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Sample records for pulverized fuel ash

  1. Soil and fertilizer amendments and edge effects on the floral succession of pulverized fuel ash

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, P. [Roehampton University, London (United Kingdom). Whitelands College

    2009-01-15

    Plots of fresh pulverized fuel ash (PFA, an industrial waste) were inoculated with soils from existing PFA sites and fertilizers in a factorial design, then left unmanaged for 12 years during which time the floral development and soil chemistry were monitored annually. For the first 3 years, the site supported a sparse mix of chenopods (including the scarce Chenopodium glaucum) and halophytes. As salinity declined, ruderals, legumes, and grasses plus the fire-site moss Funaria hygrometrica colonized, followed by Festuca arundinacea grassland (NVC community MG12) and Hippophae rhamnoides scrub. Dactylorhiza incarnata (orchidacea) appeared after 7 years, but only in plots that had received soil from existing orchid colonies. Four years later, a larger second generation of Dactylorhiza appeared, but only in the central zone of the site where vegetation was thinnest. By year 12, the site was dominated by coarse grasses and scrub, with early successional species persisting only in the sparsely vegetated center, where nitrate levels were lowest. This edge effect is interpreted as centripetal encroachment, a process of potentially wider concern for the conservation of low-fertility habitat patches. Overall, seed bank inoculation seems to have introduced few but desirable species (D. incarnata, Pyrola rotundifolia, some halophytes, and annuals), whereas initial application of organic fertilizer had long-lasting ({ge} 10 years) effects on cover and soil composition.

  2. Water permeabilities of pulverized fuel ash; Bifuntan sekitanbai no tosui tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, T. [Center for Coal Utilization, Japan, Tokyo (Japan); Nagataki, S. [Niigata University, Niigata (Japan); Hosoda, N. [Kumagai Gumi Co. Ltd., Tokyo (Japan); Utsuki, T. [The Coal Mining Research Center, Japan, Tokyo (Japan); Kubo, H. [Obayashi Corp., Tokyo (Japan)

    1996-09-01

    It is intended to establish a technology to utilize coal ash in bulk to deal with its increasing production. In order to expand its use into earth engineering materials, two kinds of combustion ashes produced from dust coal burning power plants were used for studies using different kinds of tests. The tests were carried out on strength properties, water permeability, and characteristics of dissolving trace amounts of chemical constituents, with regard to addition effects of cement into compacted and slurry-state dust coal burned ashes. The derived findings may be summarized as follows: as the strength properties, the strength for both of the compacted and slurry-state ashes increases as the cement addition ratio is increased; growth of the strength due to the cement addition ratio and material age varies depending on the kinds of dust coal burned ash; comparison of strengths of the compacted and the slurry-state ashes indicates the strength of the latter ash is about one-third to quarter of that of the former ash; water permeability of the ashes decreases both in the compacted and slurry- state ashes as the cement addition ratio is increased; and the cement addition ratio gives greater impact to the water permeability than the density of the ashes. 28 figs., 5 tabs.

  3. Pulverized fuel-oxygen burner

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Curtis; Patterson, Brad; Perdue, Jayson

    2017-09-05

    A burner assembly combines oxygen and fuel to produce a flame. The burner assembly includes an oxygen supply tube adapted to receive a stream of oxygen and a solid fuel conduit arranged to extend through the oxygen tube to convey a stream of fluidized, pulverized, solid fuel into a flame chamber. Oxygen flowing through the oxygen supply tube passes generally tangentially through a first set of oxygen-injection holes formed in the solid fuel conduit and off-tangentially from a second set of oxygen-injection holes formed in the solid fuel conduit and then mixes with fluidized, pulverized, solid fuel passing through the solid fuel conduit to create an oxygen-fuel mixture in a downstream portion of the solid fuel conduit. This mixture is discharged into a flame chamber and ignited in the flame chamber to produce a flame.

  4. Co-combustion of pulverized coal and solid recovered fuel in an entrained flow reactor - General combustion and ash behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Hao Wu; Peter Glarborg; Flemming Jappe Frandsen; Kim Dam-Johansen; Peter Arendt Jensen; Bo Sander [Technical University of Denmark, Lyngby (Denmark). Department of Chemical and Biochemical Engineering

    2011-05-15

    Co-combustion of a bituminous coal and a solid recovered fuel (SRF) was carried out in an entrained flow reactor, and the influence of additives such as NaCl, PVC, ammonium sulphate, and kaolinite was investigated. The experiments were carried out with SRF shares of 7.9 wt.%, 14.8 wt.% and 25 wt.%, respectively. The effect of additives was evaluated by maintaining the share of secondary fuel (mixture of SRF and additive) at 14.8 wt.%. The results showed that fuel burnout, NO and SO{sub 2} emission decreased with increasing share of SRF. The majority of the additives inhibited the burnout, except for NaCl which seemed to have a promoting effect. The impact of additives on NO emission was mostly insignificant, except for ammonium sulphate which greatly reduced NO emission. For SO{sub 2}, it was found that all of the additives increased the S-retention in ash. Analysis of the bulk composition of fly ash from different experiments indicated that the majority of S and Cl in the fuels were released to gas phase during combustion, whereas the K and Na in the fuels were mainly retained in ash in water insoluble form such as aluminosilicates or silicates. The addition of NaCl, PVC, and ammonium sulphate generally promoted the vaporization of Na and K, resulting in increased formation of water soluble alkalis such as alkali chlorides or sulphates. The vaporization degree of Na and K was found to be correlated during the experiments, suggesting an interaction between the vaporization of Na and K during combustion. By collecting deposits on an air-cooled probe, it was found that the ash deposition propensity in co-combustion decreased with increasing share of SRF. The addition of NaCl and PVC significantly increased the ash deposition propensity, whereas the addition of ammonium sulphate or kaolinite showed a slight reducing effect. 46 refs., 13 figs., 2 tabs.

  5. Co-combustion of pulverized coal and solid recovered fuel in an entrained flow reactor- General combustion and ash behavior

    DEFF Research Database (Denmark)

    Wu, Hao; Glarborg, Peter; Frandsen, Flemming

    2011-01-01

    .9 wt.%, 14.8 wt.% and 25 wt.%, respectively. The effect of additives was evaluated by maintaining the share of secondary fuel (mixture of SRF and additive) at 14.8 wt.%. The experimental results showed that the fuel burnout, NO and SO2 emission in co-combustion of coal and SRF were decreased...... with increasing share of SRF. The majority of the additives inhibited the burnout, except for NaCl which seemed to have a promoting effect. The impact of additives on NO emission was mostly insignificant, except for ammonium sulphate which greatly reduced the NO emission. For SO2 emission, it was found that all...

  6. Study on the influence of the amount of pulverized fuel ash on strength of reactive powder concrete%粉煤灰掺量对活性粉末混凝土强度影响的研究

    Institute of Scientific and Technical Information of China (English)

    鞠彦忠; 曲晶; 王德弘

    2014-01-01

    Through the experiments,it analysed the influence of curing conditions and the dosage of fly ash on mechanical properties of reactive powder concrete.Analysis results showed that the flexural strength of concrete was slightly increased with the increase of dosage of pulverized fuel ash,and the compressive strength reached the maximum when the ratio of pulverized fuel ash and cement was 0.3,steam curing of has a certain role in promoting the concrete strength.%通过试验研究了粉煤灰掺量和养护条件对活性粉末混凝土力学性能的影响。分析结果表明,混凝土的抗弯拉强度随着粉煤灰掺量的增加而略有增强,而抗压强度在粉煤灰水泥比为0.3时达到最大值,蒸汽养护对混凝土的强度有促进作用。

  7. 粉煤灰在含氟含磷废水处理中的应用%Application of Pulverized Fuel Ash in Treatment of Wastewater Contained with Fluorine and Phosphorus

    Institute of Scientific and Technical Information of China (English)

    邓慧; 李聪; 马宏飞; 杨翔华

    2012-01-01

    粉煤灰是火电厂排出的固体废弃物,其作为絮凝剂和吸附剂在废水处理方面已经得到了广泛的应用.人体长期过量摄人氟元素会导致地方性氟病,磷是引起水体富营养化的限制因素.该文叙述了粉煤灰在含氟含磷废水中的应用现状,探讨其影响因素和改性方法,并迸一步分析了粉煤灰除氟除磷的机理.结果表明,粉煤灰的组成,特别是其Ca/CaO含量和反应的操作条件对氟、磷的去除效果有较大的影响;酸、碱、盐、微波、负载、工艺改变和新材料转化等改性方法有利于提高粉煤灰对氟和磷的处理能力;粉煤灰对氟和磷的去除主要依赖于吸附作用和凝聚作用.%Pulverized fuel ash is a kind of industrial solid waste produced from thermo-electric plant, which has been widely used in waste water treatment as flocculant and adsorbent. Excessive fluorine intake for a long time causes endemic fluorosis, and phosphorus is the control (actor which results in eutrophication of water bodies as majority. The paper reviewed the current studies of pulverized fuel ash in fluorine and phosphorus removal, discussed the influencing factors and modified methods, analyzed the removal mechanism additionally. Results revealed that the constituents, especially Ca/CaO content, and operation condition affected the removal of fluorine and phosphorus a lot. Change of sour, alkali, salt, microwave, load, process and new material transformation were beneficial to improve pulverized fuel ash disposal capacities for fluorine and phosphorus. Fluorine and phosphorus removal by pulverized fuel ash depended on adsorption and agglomeration effects in most cases.

  8. Ash formation under pressurized pulverized coal combustion conditions

    Science.gov (United States)

    Davila Latorre, Aura Cecilia

    Coal combustion is a source of inorganic particulate matter (ash), which can deposit in boilers and also be emitted into the atmosphere becoming part of ambient fine particulate matter (PM 2.5). In order to decrease coal combustion emissions per unit of power produced, higher efficiency systems have been proposed, including systems operating at elevated pressures. These new operating conditions will affect pollutant formation mechanisms, particularly those associated with the conversion of mineral matter to ash. Ash particle formation mechanisms are particularly sensitive to changes in pressure as they are related to the structure of coal char particles at early stages of combustion. To assess the importance of pressure on ash particle formation, pyrolyzed chars and ash particles from pressurized pulverized combustion of two bituminous and one subbituminous U.S. coals at operating pressures up to 30 atm were studied. Pressure changes the distribution of char particle types, changing the spatial distribution of the minerals during the combustion process and therefore affecting particle formation mechanisms. Chars were examined by Scanning Electron Microscopy (SEM) and classified into two different types (cenospheric and solid) depending on porosity and wall thickness. A correlation for estimating the amount of these cenospheric char particles was then proposed for bituminous coals based on the operating conditions and coal maceral analysis. The ash particle size distribution of the coals combusted at different operating pressures was measured using Computer Controlled Scanning Electron Microscopy (CCSEM). The results of the char characterization and ash particle size distribution measurements were then incorporated into an ash particle formation algorithm that was proposed and implemented. The model predicts ash particle size and composition distributions at elevated pressures under conditions of complete char burnout. Ash predictions were calculated by first

  9. Low NOx nozzle tip for a pulverized solid fuel furnace

    Science.gov (United States)

    Donais, Richard E; Hellewell, Todd D; Lewis, Robert D; Richards, Galen H; Towle, David P

    2014-04-22

    A nozzle tip [100] for a pulverized solid fuel pipe nozzle [200] of a pulverized solid fuel-fired furnace includes: a primary air shroud [120] having an inlet [102] and an outlet [104], wherein the inlet [102] receives a fuel flow [230]; and a flow splitter [180] disposed within the primary air shroud [120], wherein the flow splitter disperses particles in the fuel flow [230] to the outlet [104] to provide a fuel flow jet which reduces NOx in the pulverized solid fuel-fired furnace. In alternative embodiments, the flow splitter [180] may be wedge shaped and extend partially or entirely across the outlet [104]. In another alternative embodiment, flow splitter [180] may be moved forward toward the inlet [102] to create a recessed design.

  10. Effect of Pulverized Fuel Ashes on Autogenous Shrinkage and Compressive Strength of Cement Pastes%粉煤灰对水泥浆体自收缩和抗压强度的影响

    Institute of Scientific and Technical Information of China (English)

    郝成伟; 邓敏; 莫立武; 刘开伟

    2011-01-01

    Autogenous shrinkage of cement pastes with different contents of pulverized fuel ashes(PFA) and different water-to-binder ratio were measured by a shrinkage test device. Compressive strength of sealed cement paste were also measured. The influence of PFA on the pore structures and micrograph of hydration products were investigated through mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM) , on which the influence mechanism was analyzed. Experimental results demonstrated that autogenous shrinkage of cement pastes decreased with the increased contents of PFA at early age (before 7 d) , this may be ascribed to inhibition of PFA on the shrinkage. After 7 d, however, both autogenous shrinkage, and compressive strength of cement pastes increased. This may be attributed to decrease of pore radius and densification of cement hydration products due to the pozzolanic reaction of fly ash.%设计组装了水泥浆体自收缩测量装置,进行了不同粉煤灰掺量和水胶比的水泥浆体自收缩和抗压强度测试,采用压汞测孔仪(MIP)、扫描电镜(SEM)等测试技术研究了粉煤灰对水泥浆体孔结构、产物形貌等微观结构的影响,并对其影响机理进行了分析.结果表明:粉煤灰能够有效抑制水泥浆体的早期自收缩,在7d前,其自收缩随着粉煤灰掺量的增加而减小;与纯硅酸盐水泥浆体相比,粉煤灰水泥浆体7d后的抗压强度增幅较大,但自收缩增长速率也趋于增大;火山灰反应引起的孔径细化、水化产物结构致密是粉煤灰影响水泥浆体自收缩和抗压强度的根本原因.

  11. On gas and particle radiation in pulverized fuel combustion furnaces

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    Radiation is the principal mode of heat transfer in a combustor. This paper presents a refined weighted sum of gray gases model for computational fluid dynamics modelling of conventional air-fuel combustion, which has greater accuracy and completeness than the existing gaseous radiative property....... Although the refined gaseous radiative property model shows great advantages in gaseous fuel combustion modelling, its impacts are largely compromised in pulverized solid fuel combustion, in which particle-radiation interaction plays the dominant role in radiation heat transfer due to high particle loading....... Use of conversion-dependent particle emissivity and scattering factor will not only change the particle heating and reaction history, but also alter the radiation intensity and thus temperature profiles in the furnace. For radiation modelling in pulverized fuel combustion, the priority needs...

  12. Effects of pulverized coal fly-ash addition as a wet-end filler in papermaking

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, A.S.K. [SLIET, Longowal (India). Dept. of Chemical Technology

    2008-09-15

    This experimental study is based on the innovative idea of using pulverized coal fly ash as a wet-end filler in papermaking. This is the first evaluation of the possible use of fly ash in the paper industry. Coal-based thermal power plants throughout the world are generating fly ash as a solid waste product. The constituents of fly ash can be used effectively in papermaking. Fly ash has a wide variation in particle size, which ranges from a few micrometers to one hundred micrometers. Fly ash acts as an inert material in acidic, neutral, and alkaline papermaking processes. Its physical properties such as bulk density (800-980 kg/m{sup 3}), porosity (45%-57%), and surface area (0.138-2.3076 m{sup 2}/g) make it suitable for use as a paper filler. Fly ash obtained from thermal power plants using pulverized coal was fractionated by a vibratory-sieve stack. The fine fraction with a particle size below 38 micrometers was used to study its effect on the important mechanical-strength and optical properties of paper. The effects of fly-ash addition on these properties were compared with those of kaolin clay. Paper opacity was found to be much higher with fly ash as a filler, whereas brightness decreased as the filler percentage increased Mechanical strength properties of the paper samples with fly ash as filler were superior to those with kaolin clay.

  13. Utilization of blended fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash in geopolymer.

    Science.gov (United States)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

    In this paper, synthesis of geopolymer from fluidized bed combustion (FBC) ash and pulverized coal combustion (PCC) fly ash was studied in order to effectively utilize both ashes. FBC-fly ash and bottom ash were inter-ground to three different finenesses. The ashes were mixed with as-received PCC-fly ash in various proportions and used as source material for synthesis of geopolymer. Sodium silicate (Na(2)SiO(3)) and 10M sodium hydroxide (NaOH) solutions at mass ratio of Na(2)SiO(3)/NaOH of 1.5 and curing temperature of 65 degrees C for 48h were used for making geopolymer. X-ray diffraction (XRD), scanning electron microscopy (SEM), degree of reaction, and thermal gravimetric analysis (TGA) were performed on the geopolymer pastes. Compressive strength was also tested on geopolymer mortars. The results show that high strength geopolymer mortars of 35.0-44.0MPa can be produced using mixture of ground FBC ash and as-received PCC-fly ash. Fine FBC ash is more reactive and results in higher degree of reaction and higher strength geopolymer as compared to the use of coarser FBC ash. Grinding increases reactivity of ash by means of increasing surface area and the amount of reactive phase of the ash. In addition, the packing effect due to fine particles also contributed to increase in strength of geopolymers.

  14. Oxy-fuel combustion of pulverized fuels: Combustion fundamentals and modeling

    DEFF Research Database (Denmark)

    Yin, Chungen; Yan, Jinyue

    2016-01-01

    Oxy-fuel combustion of pulverized fuels (PF), as a promising technology for CO2 capture from power plants, has gained a lot of concerns and also advanced considerable research, development and demonstration in the last past years worldwide. The use of CO2 or the mixture of CO2 and H2O vapor as th...

  15. Partitioning behavior of trace elements during pilot-scale combustion of pulverized coal and coal-water slurry fuel

    Science.gov (United States)

    Nodelman; Pisupati; Miller; Scaroni

    2000-05-29

    Release pathways for inorganic hazardous air pollutants (IHAPs) from a pilot-scale, down-fired combustor (DFC) when firing pulverized coal (PC) and coal-water slurry fuel (CWSF) were identified and quantified to demonstrate the effect of fuel form on IHAP partitioning, enrichment and emissions. The baghouse capturing efficiency for each element was calculated to determine the effectiveness of IHAP emission control. Most of the IHAPs were enriched in the fly ash and depleted in the bottom ash. Mercury was found to be enriched in the flue gas, and preferentially emitted in the vapor phase. When firing CWSF, more IHAPs were partitioned in the bottom ash than when firing PC. Significant reduction of Hg emissions during CWSF combustion was also observed.

  16. A simple numerical model to estimate the effect of coal selection on pulverized fuel burnout

    Energy Technology Data Exchange (ETDEWEB)

    Sun, J.K.; Hurt, R.H.; Niksa, S.; Muzio, L.; Mehta, A.; Stallings, J. [Brown University, Providence, RI (USA). Division Engineering

    2003-06-01

    The amount of unburned carbon in ash is an important performance characteristic in commercial boilers fired with pulverized coal. Unburned carbon levels are known to be sensitive to fuel selection, and there is great interest in methods of estimating the burnout propensity of coals based on proximate and ultimate analysis - the only fuel properties readily available to utility practitioners. A simple numerical model is described that is specifically designed to estimate the effects of coal selection on burnout in a way that is useful for commercial coal screening. The model is based on a highly idealized description of the combustion chamber but employs detailed descriptions of the fundamental fuel transformations. The model is validated against data from laboratory and pilot-scale combustors burning a range of international coals, and then against data obtained from full-scale units during periods of coal switching. The validated model form is then used in a series of sensitivity studies to explore the role of various individual fuel properties that influence burnout.

  17. Binary Effect of Fly Ash and Palm Oil Fuel Ash on Heat of Hydration Aerated Concrete

    Directory of Open Access Journals (Sweden)

    Taha Mehmannavaz

    2014-01-01

    Full Text Available The binary effect of pulverized fuel ash (PFA and palm oil fuel ash (POFA on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I, binary concrete made from 50% POFA (Type II, and ternary concrete containing 30% POFA and 20% PFA (Type III. It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern.

  18. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    Science.gov (United States)

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern.

  19. A Model for Nitrogen Chemistry in Oxy-Fuel Combustion of Pulverized Coal

    OpenAIRE

    Hashemi, Hamid; Hansen, Stine; Toftegaard, Maja Bøg; Pedersen, Kim Hougaard; Jensen, Anker Degn; Dam-Johansen, Kim; Glarborg, Peter

    2011-01-01

    In this work, a model for the nitrogen chemistry in the oxy-fuel combustion of pulverized coal has been developed. The model is a chemical reaction engineering type of model with a detailed reaction mechanism for the gas-phase chemistry, together with a simplified description of the mixing of flows, heating and devolatilization of particles, and gas–solid reactions. The model is validated by comparison with entrained flow reactor results from the present work and from the literature on pulver...

  20. Renewable wood fuel: Fuel feed system for a pulverized coal boiler. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    This report evaluates a pilot test program conducted by New York State Gas & Electric Corporation to evaluate the feasibility of co-firing a pulverized coal plant with renewable wood fuels. The goal was to establish that such a co-firing system can reduce air emissions while maintaining good operational procedures and cost controls. The test fuel feed system employed at Greenidge Station`s Boiler 6 was shown to be effective in feeding wood products. Emission results were promising and an economic analysis indicates that it will be beneficial to pursue further refinements to the equipment and systems. The report recommends further evaluation of the generation and emission impacts using woods of varied moisture contents and at varied Btu input rates to determine if a drying system would be a cost-effective option.

  1. Plasma system for start-up of pulverized fuel-fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Dyjakon, A.K. [Wroclaw Univ. of Technology, Wroclaw (Poland). Inst. of Power Engineering and Fluid Mechanics

    2009-07-01

    Pulverized coal combustion requires preliminary heating of the combustion chamber. Conventional heavy oil start-up systems are used during the boiler kindling, resulting in pollution, additional maintenance and high cost. This paper described the advantages of a plasma start-up system for the ignition and stabilization of a pulverized coal flame in coal-fired steam boiler. In a plasma start-up system, the heat source for ignition and stabilization of the pulverized coal combustion is a plasma at a temperature of 5,000 to 10,000 degrees C. The plasma interaction involves rapid heating of coal particles and thermal decomposition of the organic compounds resulting in fast release of the volatile matter and destruction of particles below 5 {mu}m. It also involves thermal dissociation of gaseous products with radical generation and gas ionization. The highly reactive mixture that is produced promotes flame propagation in the presence of oxygen. A continuous plasma discharge in a pulverized burner stabilizes the dust flame. This paper described the advantages associated with the use of a plasma start-up system, such as the possibility of limiting pollutant emissions to the atmosphere. It also presented laboratory study results on the influence of the fuels such as lignite, bituminous coal, wood and carbonaceous shale and their properties on the operational range of the plasma assisted pulverized coal burner. 13 refs., 2 tabs., 7 figs.

  2. Effects of moisture release and radiation properties in pulverized fuel combustion: A CFD modelling study

    DEFF Research Database (Denmark)

    Yin, Chungen

    2016-01-01

    Pulverized fuels (PF) prepared and fired in utility boilers always contain some moisture. For some fuels with high moisture contents (e.g., brown coals), the share of the evaporation enthalpy is quite significant compared to the heat released during combustion, which often needs to be reclaimed.......g., oxy-fuel or air–fuel), account for the variations in CO2 and H2O concentrations in a flame, and include the impacts of other participating gases (e.g., CO and hydrocarbons) needs to be derived for combustion CFD community....

  3. On-line tracking of pulverized coal and biomass fuels through flame spectrum analysis

    Institute of Scientific and Technical Information of China (English)

    迟天阳; 张宏建

    2007-01-01

    This paper presents a new approach to the on-line tracking of pulverized coal and biomass fuels through flame spectrum analysis. A flame detector containing four photodiodes is used to derive multiple signals covering a wide spectrum of the flame from visible, near-infrared and mid-infrared spectral bands as well as a part of far-infrared band. Different features are extracted in time and frequency domains to identify the dynamic "fingerprints" of the flame. Fuzzy logic inference techniques are employed to combine typical features together and infer the type of fuel being burnt. Four types of pulverized coal and five types of biomass are burnt on a laboratory-scale combustion test rig. Results obtained demonstrate that this approach is capable of tracking the type of fuel under steady combustion conditions.

  4. Cofiring coal-water slurry fuel with pulverized coal as a NOx reduction strategy

    Energy Technology Data Exchange (ETDEWEB)

    Miller, B.G.; Miller, S.F.; Morrison, J.L.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States)

    1997-12-31

    A low solids, low viscosity coal-water slurry fuel (CWSF) was formulated and produced from impounded bituminous coal fines and burned in a utility-scale boiler to investigate NOx emissions reduction during the cofiring of CWSF with pulverized coal. Tests were conducted at the Pennsylvania Electric Company (Penelec) Seward Station, located near Seward, Pennsylvania in a Babcock and Wilcox (B and W), front-wall fired, pulverized coal boiler (34 MWe). Two B and W pulverizers feed coal to six burners (two burner levels each containing three low-NOx burners). Approximately 20% of the thermal input was provided by CWSF, the balance by pulverized coal. There was a significant reduction of NOx emissions when cofiring CWSF and pulverized coal as compared to firing 100% pulverized coal. The level of reduction was dependent upon the cofiring configuration (i.e., cofiring in the upper three, lower three, or all six burners), with NOx emissions being reduced by as much as 26.5%. The reduction in NOx emissions was not due to the tempering effect of the water in the CWSF, because a greater reduction in NOx occurred when cofiring CWSF than when injecting the same quantity of water at the same boiler firing rate. This paper discusses the tests in detail and the proposed reburn mechanism for the NOx reduction. In addition, combustion test results from the front-wall fired unit at the Seward Station will be compared to CWSF cofire tests that have been conducted at cyclone-fired units at Tennessee Valley Authority`s (TVA) Paradise Station (704 MWe), Drakesboro, Kentucky and Southern Illinois Power Cooperative`s (SIPC) Marion, Illinois Station (33 MWe).

  5. Pulverized coal and substitute fuels for the cement manufacturing industry

    Energy Technology Data Exchange (ETDEWEB)

    Dobrowsky, F.

    1981-01-01

    This paper comprises an article of general technical interest on coal and its use in the cement industry, plus the scope for using substitute fuels. Discusses coal properties and preparation (crushing). Describes the heating systems of the cement ovens: burners, combustion and parameters governing flame-length. Looks at operation problems connected with heating of the coal: caking, fusing, clinker quality and behaviour of the refractory bricks. Also discusses substitute fuels: type of fuel, scope for utilisation and requisite precautions. 32 refs.

  6. Impacts and implementation of fuel moisture release and radiation properties in modelling of pulverized fuel combustion processes

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    Pulverized fuels (PF) prepared and fired in utility boilers usually contain a certain amount of moisture, either free moisture or chemically bound moisture. In PF furnaces, radiation which is the principal mode of heat transfer consists of contribution from both gas and particle phase. This paper...... presents different methods for fuel moisture release and new models for gas and particle radiative properties, and demonstrates their implementation, importance and impacts in PF combustion modelling via a comprehensive CFD study of a pulverized coal-fired utility boiler. To conclude, it is recommended...... to add the free moisture into the primary air stream while lump the moisture retained in the feed after the mills with volatiles in PF combustion modelling. For gas and particle radiation in PF boilers, it is found that particle radiation largely overwhelms gas radiation due to high particle loading...

  7. Impact of Coal Fly Ash Addition on Combustion Aerosols (PM2.5) from Full-Scale Suspension-Firing of Pulverized Wood

    DEFF Research Database (Denmark)

    Damø, Anne Juul; Wu, Hao; Frandsen, Flemming

    2014-01-01

    The formation of combustion aerosols was studied in an 800 MWth suspension-fired power plant boiler, during combustion of pulverized wood pellets with and without addition of coal fly ash as alkali capture additive. The aerosol particles were sampled and characterized by a low-pressure cascade...

  8. Characterization of bottom ashes from coal pulverized power plants to determine their potential use feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Menendez, E.; Alvaro, A. M.; Argiz, C.; Parra, J. L.; Moragues, A.

    2013-07-01

    The disposal of coal by products represents environmental and economical problems around the world. Therefore, the reuse and valorisation of this waste has become an important issue in the last decades. While high-value construction products containing fly ash were developed and its use is actually totally accepted as an addition to cement, the use of the bottom ash as supplementary cementitious material has not been allow. This paper examines the chemical and physical properties of fly ashes and bottom ashes from two different coal power plants in order to compare them and analyse the potential feasibility of bottom ash as cement replacement. The mechanical properties of cement mortars made with different percentages of both ashes were also study. The results obtained showed similar chemical composition of both kinds of ashes. The compressive strength values of mortars with 10 % and 25 % of cement replacement (at 28 days) were above the limits established in European standards and there were not significant differences between fly ash and bottom ash from both origins. (Author)

  9. Investigation of Fly Ash and Activated Carbon Obtained from Pulverized Coal Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Edward K. Levy; Christopher Kiely; Zheng Yao

    2006-08-31

    One of the techniques for Hg capture in coal-fired boilers involves injection of activated carbon (AC) into the boiler downstream of the air preheater. Hg is adsorbed onto the AC particles and fly ash, which are then both removed in an electrostatic precipitator or baghouse. This project addressed the issues of Hg on activated carbon and on fly ash from a materials re-use point of view. It also addressed the possible connection between SCR reactors, fly ash properties and Hg capture. The project has determined the feasibility of separating AC from fly ash in a fluidized bed and of regenerating the separated AC by heating the AC to elevated temperatures in a fluidized bed. The temperatures needed to drive off the Hg from the ash in a fluidized bed have also been determined. Finally, samples of fly ash from power plants with SCR reactors for NO{sub x} control have been analyzed in an effort to determine the effects of SCR on the ash.

  10. Behavior study of trace elements in pulverized lignite, bottom ash, and fly ash of Amyntaio power station, Greece.

    Science.gov (United States)

    Megalovasilis, Pavlos; Papastergios, Georgios; Filippidis, Anestis

    2013-07-01

    The Kozani-Ptolemais-Amyntaio basin constitutes the principal coal field of Greece. Approximately 50% of the total power production of Greece is generated by five power stations operating in the area. Lignite samples, together with the corresponding fly ash and bottom ash were collected, over a period of 3 months, from the power plant of Amyntaio and analyzed for their content in 16 trace elements. The results indicate that Y, Nb, U, Rb, Zr, Ni, Pb, Ba, Zn, Sr, Cu, and Th demonstrate an organic affinity during the combustion of lignite, while V has an inorganic affinity. Three elements (Co, Cr, and Sc) show an intermediate affinity.

  11. 论路用混凝土掺合料——粉煤灰%Road Mixes the Material with the Concretes Pulverized Coal Ash

    Institute of Scientific and Technical Information of China (English)

    李吉平

    2009-01-01

    This paper introduced the road mixes the material pulverized coal ash with the concretes the characteristic, technical performance, to pulverized coal ash quality requirement, standard, choice, design requirements and isometric substitution law and excess substitution method com-putation principle.%文章介绍了路用混凝土掺合料粉煤灰的特点、技术性能、对粉煤灰的质量要求、标准、选择,以及设计要求和配制混凝土时取代水泥的等量取代法和超量取代法的计算原理.

  12. Pyrite thermochemistry, ash agglomeration, and char fragmentation during pulverized coal combustion. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Akan-Etuk, A.; Diaz, R.; Niksa, S.

    1991-10-01

    The objective of the present work is to introduce an experimental program that will eventually lead to time-resolved iron ash composition over the technological operating domain. The preceding literature survey suggests two important stipulations on any such experimental program. The first stipulation is that good control must be established over the operating conditions, to accurately quantify their effects. The other is that data must be obtained rapidly, to thoroughly cover the important operating domain. This work presents a series of studies that has characterized the desulfurization of pyrite during the early stages of combustion. An experimental system was established and used to monitor the effects of oxygen, temperature, and residence time on the evolution of condensed phase products of the combustion of pure pyrite. (VC)

  13. Pyrite thermochemistry, ash agglomeration, and char fragmentation during pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Akan-Etuk, A.; Diaz, R.; Niksa, S.

    1991-10-01

    The objective of the present work is to introduce an experimental program that will eventually lead to time-resolved iron ash composition over the technological operating domain. The preceding literature survey suggests two important stipulations on any such experimental program. The first stipulation is that good control must be established over the operating conditions, to accurately quantify their effects. The other is that data must be obtained rapidly, to thoroughly cover the important operating domain. This work presents a series of studies that has characterized the desulfurization of pyrite during the early stages of combustion. An experimental system was established and used to monitor the effects of oxygen, temperature, and residence time on the evolution of condensed phase products of the combustion of pure pyrite. (VC)

  14. Performance appraisal of the spent fuel dry pulverizing/mixing device

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, J. H.; Youn, J. S.; Hong, D. H.; Kim, Y. H.; Jin, J. H. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    The spent fuel dry pulverizing/mixing device is used to deal with the spent fuels for the safe disposal. The separated pellets from hulls by a slitting device are put and oxidized from UO{sub 2} solid pellet to U{sub 3}O{sub 8} powder in the device. The device have been developed based on a voloxidation method which is one of several dry de-cladding methods. We have benchmarked dry de-cladding methods, analyzed applicability to the advanced spent fuel management process, integrated and compared several configuration, and finally derived detailed specifications proper to requirements for the device. Also, thermal characteristics of the device such as thermal stress and strain have been analyzed by the commercial software, I-DEAS, and the reliability of the results have been verified by the KOLAS(KOrea Laboratory Accrediation Scheme). The UO{sub 2} solid pellets are put in the device which has a capacity of 20 kgHM per a batch, heated up about 500 .deg. C in the air environment. Then, the UO{sub 2} solid pellets are oxidized into the U{sub 3}O{sub 8} powder, and the powder is collected in a special vessel. The device has been designed and developed as follows: the multi-staged fine hole meshes are used to reduce the size of the powder gradually, heat and air(oxygen) are supplied continuously to reduce the reaction time, and slight vibration effect are applied to collect powder cling to the device. Based on these results, it will be effectively applied to available data for designing and producing of the hot test facility.

  15. Mechanism development of the spent fuel dry pulverizing/mixing device

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J. H.; Hong, D. H.; Kim, Y. H.; Yoon, J. S.; Jin, J. H.; Park, K. Y.; Song, T. G. [KAERI, Taejon (Korea, Republic of)

    2002-10-01

    The spent fuel dry pulverizing/mixing device mechanism is used to deal with the spent fuels for the safe disposal. The separated pellets from hulls by a slitting device are put and oxidized from UO{sub 2} solid pellet to U{sub 3}O{sub 8} powder in the device. The device have been developed based on a voloxidation method which is one of several dry de-cladding methods. We have benchmarked dry de-cladding methods, analyzed applicability to the advanced spent fuel management process, integrated and compared several configuration, and finally derived detailed specifications proper to requirements for the device. Also, thermal characteristics of the device such as thermal stress and strain have been analyzed by the commercial software, I-DEAS, and the reliability of the results have been verified by the KOLAS(KOrea Laboratory Accreditation Scheme). The UO{sub 2} solid pellets are put in the device which has a capacity of 20 kgHM per a batch, heated up about 600 .deg. C in the air environment. Then, the UO{sub 2} solid pellets are oxidized into the U{sub 3}O{sub 8} powder, and the powder is collected in a special vessel. The device has been development as follows: the multi-staged fine hole meshes are used to reduce the size of the powder gradually, heat and air(oxygen) are supplied continuously to reduce the reaction time, and slight vibration effect are applied to collect powder cling to the device.

  16. Fly Ash Formation during Suspension-Firing of Biomass. Effects of Residence Time and Fuel-Type

    DEFF Research Database (Denmark)

    Damø, Anne Juul; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2017-01-01

    The objective of this work was to generate comprehensive data on the formation of residual fly ash during the initial stages of suspension-firing of biomass. Combustion experiments were carried out with pulverized biomass fuels (two straw fuels and two wood fuels), in an entrained flow reactor...... at 1200-1400 °C, simulating full-scale suspension-firing of biomass. By the use of a movable, cooled and quenched gas/particle sampling probe, samples were collected at different positions along the vertical axis in the reactor, corresponding to gas residence times ranging from 0.25 – 2.0s. The collected...... particles were subjected to various analyses, including char burnout level, particle size distribution, elemental composition, and particle morphology and composition. Furthermore, the transient release, i.e. the vaporization of the flame-volatile inorganic elements K, Cl and S, from the burning fuel...

  17. CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS (CFB AND CLB) FUELS IN PULVERIZED FUEL AND FIXED BED BURNERS

    Energy Technology Data Exchange (ETDEWEB)

    Kalyan Annamalai; John Sweeten; Saqib Mukhtar; Ben Thein; Gengsheng Wei; Soyuz Priyadarsan; Senthil Arumugam; Kevin Heflin

    2003-08-28

    Intensive animal feeding operations create large amounts of animal waste that must be safely disposed of in order to avoid environmental degradation. Cattle feedlots and chicken houses are two examples. In feedlots, cattle are confined to small pens and fed a high calorie grain-diet diet in preparation for slaughter. In chicken houses, thousands of chickens are kept in close proximity. In both of these operations, millions of tons of manure are produced every year. The manure could be used as a fuel by mixing it with coal in a 90:10 blend and firing it in an existing coal suspension fired combustion systems. This technique is known as co-firing, and the high temperatures produced by the coal will allow the biomass to be completely combusted. Reburn is a process where a small percentage of fuel called reburn fuel is injected above the NO{sub x} producing, conventional coal fired burners in order to reduce NO{sub x}. The manure could also be used as reburn fuel for reducing NO{sub x} in coal fired plants. An alternate approach of using animal waste is to adopt the gasification process using a fixed bed gasifier and then use the gases for firing in gas turbine combustors. In this report, the cattle manure is referred to as feedlot biomass (FB) and chicken manure as litter biomass (LB). The report generates data on FB and LB fuel characteristics. Co-firing, reburn, and gasification tests of coal, FB, LB, coal: FB blends, and coal: LB blends and modeling on cofiring, reburn systems and economics of use of FB and LB have also been conducted. The biomass fuels are higher in ash, lower in heat content, higher in moisture, and higher in nitrogen and sulfur (which can cause air pollution) compared to coal. Small-scale cofiring experiments revealed that the biomass blends can be successfully fired, and NO{sub x} emissions will be similar to or lower than pollutant emissions when firing coal. Further experiments showed that biomass is twice or more effective than coal when

  18. Application of Fly Ash from Solid Fuel Combustion in Concrete

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard

    2008-01-01

    reactor to test the impact of changes in operating conditions and fuel type on the AEA adsorption of ash and NOx formation. Increased oxidizing conditions, obtained by improved fuel-air mixing or higher excess air, decreased the AEA requirements of the produced ash by up to a factor of 25. This was due...... on a carbon black. The reactor was modeled with CFD and a relationship between oxygen concentration in the early stage of combustion and the AEA adsorption properties of the ash was observed. The NOx formation increased by up to three times with more oxidizing conditions and thus, there was a trade....... The AEA requirements of a fly ash can be suppressed by exposing it to oxidizing species, which oxidizes the carbon surface and thus prevents the AEA to be adsorbed. In the present work, two fly ashes have been ozonated in a fixed bed reactor and the results showed that ozonation is a potential post...

  19. CO-FIRING COAL, FEEDLOT, AND LITTER BIOMASS (CFB AND LFB) FUELS IN PULVERIZED FUEL AND FIXED BED BURNERS

    Energy Technology Data Exchange (ETDEWEB)

    Kalyan Annamalai; John Sweeten; Saqib Mukhtar; Ben Thien; Gengsheng Wei; Soyuz Priyadarsan

    2002-01-15

    Intensive animal feeding operations create large amounts of animal waste that must be safely disposed of in order to avoid environmental degradation. Cattle feedlots and chicken houses are two examples. In feedlots, cattle are confined to small pens and fed a high calorie grain diet in preparation for slaughter. In chicken houses, thousands of chickens are kept in close proximity. In both of these operations, millions of tons of manure are produced every year. In this project a co-firing technology is proposed which would use manure that cannot be used for fertilizer, for power generation. Since the animal manure has economic uses as both a fertilizer and as a fuel, it is properly referred to as feedlot biomass (FB) for cow manure, or litter biomass (LB) for chicken manure. The biomass will be used a as a fuel by mixing it with coal in a 90:10 blend and firing it in existing coal fired combustion devices. This technique is known as co-firing, and the high temperatures produced by the coal will allow the biomass to be completely combusted. Therefore, it is the goal of the current research to develop an animal biomass cofiring technology. A cofiring technology is being developed by performing: (1) studies on fundamental fuel characteristics, (2) small scale boiler burner experiments, (3) gasifier experiments, (4) computer simulations, and (5) an economic analysis. The fundamental fuel studies reveal that biomass is not as high a quality fuel as coal. The biomass fuels are higher in ash, higher in moisture, higher in nitrogen and sulfur (which can cause air pollution), and lower in heat content than coal. Additionally, experiments indicate that the biomass fuels have higher gas content, release gases more readily than coal, and less homogeneous. Small-scale boiler experiments revealed that the biomass blends can be successfully fired, and NO{sub x} pollutant emissions produced will be similar to or lower than pollutant emissions when firing coal. This is a surprising

  20. The aerodynamics of the near field of pressurised pulverized fuel combustors

    Energy Technology Data Exchange (ETDEWEB)

    Bergeles, G.; Anagnostopoulos, J.; Papadakis, G.; Mouzakis, F.; Voyages, C. [National Technical University of Athens, Athens (Greece). Lab. for Aerodynamics, Dept. of Mechanical Engineering

    1998-12-31

    This research aims at improving knowledge of an effective design of pressurized pulverized fuel combustors (PPFC). Problems investigated are slag, cleaning efficiency, near burner aerodynamics and effects of pressure on combustion characteristics and on NO concentration levels. The Coal Combustion Algorithm (CO. C.A.-3D code) was the basis for the numerical work performed. Several new models were developed and incorporated into the basic code; a model for the calculation of slag formation, thickness and flow inside a PPFC, three different techniques for domain decomposition by the use of locally refined, staggered or collocated grids; an improved NO postprocessor to account for elevated pressure and turbulence effects. A new version of the final code was developed to obtain solutions in 3-D, cylindrical co-ordinates. All the above models were validated using available experimental data. The slag model predictions were in agreement with the practical evidence. The advantages and disadvantages of each of the domain decomposition techniques were assessed. The best proposed technique was found to combine simplicity, increased accuracy of the predictions in complex flow regions, and significantly reduced computer memory and storage requirements. The use of cylindrical co-ordinates for calculations inside cylindrical-type combustion chambers was found to achieve a more stable convergence of the algorithm and a considerable reduction of numerical diffusion. The proposed modifications of a basic NO formation model produced very encouraging predictions in a wide range of combustion conditions examined (various pressures, temperatures and oxygen concentrations). The numerical work performed provides a engineering tool to improve the physical understanding of the effects of pressurization on the performance and efficiency of combustor design. 33 refs., 25 figs., 2 tabs.

  1. Deposit formation in a full-scale pulverized wood-fired power plant with and without coal fly ash addition

    DEFF Research Database (Denmark)

    Wu, Hao; Shafique Bashir, Muhammad; Jensen, Peter Arendt

    2013-01-01

    temperatures of ~1300oC and ~800oC, respectively. It was found that during pulverized wood combustion, the deposit formation at the hightemperature location was characterized by a slow and continuous growth of deposits followed by the shedding of a large layer of deposits, while the deposit formation...

  2. Effect of fuel properties on the bottom ash generation rate by a laboratory fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Rozelle, P.L.; Pisupati, S.V.; Scaroni, A.W. [Penn State University, University Park, PA (United States). Dept. of Energy & Geoenvironmental Engineering

    2007-06-15

    The range of fuels that can be accommodated by an FBC boiler system is affected by the ability of the fuel, sorbent, and ash-handling equipment to move the required solids through the boiler. Of specific interest is the bottom ash handling equipment, which must have sufficient capacity to remove ash from the system in order to maintain a constant bed inventory level, and must have sufficient capability to cool the ash well below the bed temperature. Quantification of a fuel's bottom ash removal requirements can be useful for plant design. The effect of fuel properties on the rate of bottom ash production in a laboratory FBC test system was examined. The work used coal products ranging in ash content from 20 to 40+ wt. %. The system's classification of solids by particle size into flyash and bottom ash was characterized using a partition curve. Fuel fractions in the size range characteristic of bottom ash were further analyzed for distributions of ash content with respect to specific gravity, using float sink tests. The fuel fractions were then ashed in a fixed bed. In each case, the highest ash content fraction produced ash with the coarsest size consist (characteristic of bottom ash). The lower ash content fractions were found to produce ash in the size range characteristic of flyash, suggesting that the high ash content fractions were largely responsible for the production of bottom ash. The contributions of the specific gravity fractions to the composite ash in the fuels were quantified. The fuels were fired in the laboratory test system. Fuels with higher amounts of high specific gravity particles, in the size ranges characteristic of bottom ash, were found to produce more bottom ash, indicating the potential utility of float sink methods in the prediction of bottom ash removal requirements.

  3. Suppression of fine ash formation in pulverized coal flames. Final technical report, September 30, 1992--January 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Kramlich, J.C.; Chenevert, B.; Park, Jungsung; Hoffman, D.A.; Butcher, E.K.

    1996-07-19

    Coal ash, and particularly fine fly ash, remain one of the principal practical and environmental problems in coal-based power generation. In particular, submicron aerosols are identified with direct inhalation risk. Submicron ash is thought to arise from mineral vaporization during char combustion, followed by nucleation, condensation and coagulation to yield an aerosol. While aerosols are predominantly made out of volatile alkali minerals, they also can include refractory oxides that are chemically reduced to more volatile forms within the char particle and vaporized. Most of the ash of size greater than 1 {mu}m is generated by agglomeration of mineral as the char particle bums out. These two principal mechanisms are thought to account for most of the ash generated in coal combustion. Previous research has shown that various forms of coal treatment can influence the yields of fine ash from combustion. The research reported here investigates various forms of treatment, including physical coal cleaning, aerodynamic sizing, degree of grinding, and combinations of these on both aerosol yields and on yields of fine residual ash (1-4 {mu}m). The work also includes results from the combustion of artificial chars that include individual mineral elements. This research shows that these various forms of coal treatment can significantly change ash characteristics. While none of the treatments affected the bulk of the residual ash size distribution significantly, the yield of the ash aerosol mode (d<0.5 {mu}m) and fine residual ash mode (1-4 {mu}m) are changed by the treatments.

  4. Ash liberation from included minerals during combustion of pulverized coal: the relationship with char structure and burnout

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H.; Wall, T.; Liu, G.; Bryant, G. [University of Newcastle, Callaghan, NSW (Australia). CRC for Black Coal Utilization and Dept. of Chemical Engineering

    1999-12-01

    In this study, the float fraction ({lt} specific gravity of 2.0) of a size cut (63-90 {mu}m) bituminous coal was combusted in a drop tube furnace (DTF) at a gas temperature of 1300{degree}C under an atmosphere of air, to investigate the ash liberation at five coal burnoff levels (35.5%, 54.3%, 70.1%, 87.1% and 95.6%). The data indicated that char structure determines the ash liberation at different burnoff levels. Fragmentation of porous char was found to be the determinative mechanism for formation of fine ash during the early and middle stages of char combustion, while coalescence of included mineral matter determines the coarse ash formed in the later stages of combustion. The investigation confirmed that the char morphology and structure play a key role in determining char fragmentation, char burnout history, and the ash liberation during combustion. 35 refs., 5 figs., 2 tabs.

  5. Plasma-fuel systems for environment and economy indexes of pulverized coal incineration and gasification improvement

    Energy Technology Data Exchange (ETDEWEB)

    E. Karpenko; V. Messerle; A. Ustimenko [United Power System of Russia, Gusinoozersk (Russian Federation). Branch Centre of Plasma-Power Technologies of Russian J.S.Co.

    2003-07-01

    Coal is one of the main energy resources. To improve efficiency of coal incineration new plasma-energy technologies are developing. Steam-productivity 75t/h 670t/h boilers were tested for their starting up by plasma ignition of pulverized coal and flame stabilization. Laboratory (coal consumption to 20kg/h) and pilot (coal consumption 300kg/h and 32000kg/h) plasma gasification experiments are given. Plasma air and steam gasification of coal with its mineral mass utilization is studied. 8 refs., 10 figs., 4 tabs.

  6. Monitoring the species of arsenic, chromium and nickel in milled coal, bottom ash and fly ash from a pulverized coal-fired power plant in western Canada.

    Science.gov (United States)

    Goodarzi, F; Huggins, F E

    2001-02-01

    The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.

  7. Application of pulverized fly-ash and spray-dry absorption products in sand/lime-brick production

    Energy Technology Data Exchange (ETDEWEB)

    Bloem, P.J.; Sciarone, B.J.

    1989-02-01

    The application of spray-dry absorption (SDA) products in sand/lime bricks was examined to find out more about the possibilities of utilizing these products that consist mainly of calcium sulphite and calcium sulphate. Sand/lime samples containing mixtures of fly-ash and SDA products in various quantities were prepared on a laboratory scale for the purpose. The green samples were autoclaved at 460 K for eight hours. The results regarding the application of these mixtures as partial substitutes for sand were encouraging with respect to strength, porosity and absorption coefficient with capillary action of water. The best results were achieved when the mixture of sand and fly-ash/SDA-product had a ratio of about one. These results were only slightly influenced by the sulphite/sulphate ratio of the SDA products and by the calcium-chloride content. It was also found that the quantity of lime necessary for the autoclaving reaction could be decreased by adding a fly-ash/SDA-product mixture. The application of fly-ashes is limited by their carbon content (about 6 wt%). Efflorescence was not found for sodium- or potassium-sulphate contents lower than 0.4 or 2.2 wt%, respectively. 15 figs., 3 refs., 2 tabs.

  8. The relationship of post-fire white ash cover to surface fuel consumption

    Science.gov (United States)

    Andrew T. Hudak; Roger D. Ottmar; Robert E. Vihnanek; Nolan W. Brewer; Alistair M. S. Smith; Penelope Morgan

    2013-01-01

    White ash results from the complete combustion of surface fuels, making it a logically simple retrospective indicator of surface fuel consumption. However, the strength of this relationship has been neither tested nor adequately demonstrated with field measurements. We measured surface fuel loads and cover fractions of white ash and four other surface materials (green...

  9. Measurements and modeling of pulverized fuel char in an entrained flow reactor

    Science.gov (United States)

    Kebria, Mazdak

    In recent years, the combustion zone of utility boilers were modified for NOx control and this made the task of maintaining low residual carbon levels in boiler fly ash much more difficult. To predict the relationships between boiler operating conditions and residual carbon-in-ash, there is a need for improvements in determining the appropriate char reactivity to use in simulating coal-fired combustors and in relating this reactivity to unburned coal characteristics. To aid in this effort, a tubular, downward-fired, refractory-lined, laminar entrained flow reactor (EFR) was built to provide a pilot scale environment with 2 seconds residence time for studying coal combustion. Using a commercial CFD code (FLUENT), a three dimensional numerical model of coal burning in the EFR was created to evaluate common char burnout kinetic modeling approaches. EFR experimental data was obtained for operating conditions adjusted to reproduce particle Lagrangian temperature and oxygen concentration time histories typically found in coal-fired utility boilers. The radial temperature profiles were measured at different axial locations in the EFR with a suction pyrometer and thermocouples. The temperature distribution in the reactor agreed well with the simulations. A gas analyzer with a quenching probe was used to measure the oxygen distribution to similarly confirm oxygen distribution in the EFR. A semi-isokinetic particulate sampling probe was used to extract ash samples at different heights in the reactor to measure the evolution of loss on ignition (LOI). Measured LOI values were used to validate the model against predicted values. Reaction kinetics rates in the model were adjusted to bring agreement between calculated LOI and the measured values from the experimental results. The LOI predictions by kinetic-diffusion and CBK model are very similar at the late stage of char burnout. The results indicate that we can achieve sufficient accuracy for the prediction of final carbon-in-ash

  10. FUNDAMENTAL INVESTIGATION OF FUEL TRANSFORMATIONS IN PULVERIZED COAL COMBUSTION AND GASIFICATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Joseph Calo; Thomas H. Fletcher; Alan Sayre

    2005-04-29

    The goal of this project was to carry out the necessary experiments and analyses to extend current capabilities for modeling fuel transformations to the new conditions anticipated in next-generation coal-based, fuel-flexible combustion and gasification processes. This multi-organization, multi-investigator project has produced data, correlations, and submodels that extend present capabilities in pressure, temperature, and fuel type. The combined experimental and theoretical/computational results are documented in detail in Chapters 1-8 of this report, with Chapter 9 serving as a brief summary of the main conclusions. Chapters 1-3 deal with the effect of elevated pressure on devolatilization, char formation, and char properties. Chapters 4 and 5 deal with advanced combustion kinetic models needed to cover the extended ranges of pressure and temperature expected in next-generation furnaces. Chapter 6 deals with the extension of kinetic data to a variety of alternative solid fuels. Chapter 7 focuses on the kinetics of gasification (rather than combustion) at elevated pressure. Finally, Chapter 8 describes the integration, testing, and use of new fuel transformation submodels into a comprehensive CFD framework. Overall, the effects of elevated pressure, temperature, heating rate, and alternative fuel use are all complex and much more work could be further undertaken in this area. Nevertheless, the current project with its new data, correlations, and computer models provides a much improved basis for model-based design of next generation systems operating under these new conditions.

  11. Gasification reactivity and ash behaviour of biomass fuels

    Energy Technology Data Exchange (ETDEWEB)

    Moilanen, A.; Kurkela, E. [VTT Energy, Espoo (Finland)

    1998-12-31

    Measuring data required for describing the reactivity and ash sintering behaviour of biomass-based solid fuels for atmospheric and pressurised gasification are discussed. The measurements were carried out in a pressurisable thermobalance and bench-scale fluidised bed reactors. The main variables were temperature and partial pressures of H{sub 2}O and H{sub 2}, and CO{sub 2} and CO. The reaction rates were determined in binary gas mixtures H{sub 2}O-H{sub 2}, and CO{sub 2}-CO as well as in product gas mixtures H{sub 2}O-H{sub 2}-CO{sub 2}-CO. The total pressure range was 1-30 bar and the temperature range 650-950 deg C. For wood, kinetic parameters were determined using the Langmuir-Hinshelwood kinetics, which takes into account the effect of the product gases on the reaction rate. The results indicated that the H{sub 2}O-H{sub 2} system was well in conformity with this kinetics, while the reaction rates measured for the CO{sub 2}-CO system required the description of the catalytic effects of the ash-forming material. In the gasification of wood as well as of other biomasses, the behaviour of catalytically active ash components is more complex during char gasification. Experimental set-ups used for gasification reactivity measurements were compared in Aabo Akademi University and in VTT. The set-ups were pressurised thermogravimetric reactor (PTG), pressurised grid heater (PGH), pressurised bench-scale fluidised bed reactor (PFB), and pressurised entrained flow reactor (PEF). In addition, the effect of stabilising heat treatment was tested. The samples used in the study were wood, black liquor, peat, and coal. The gasification reactivity measurements were carried out in the temperature range of 700-950 deg C, and in the pressure range of 1-10 bar. The gasification agent was either CO{sub 2} in N{sub 2} or CO-CO{sub 2} mixture in N{sub 2}. In the pyrolysis carried out in different devices, mainly the same pressure and temperature were used as in the char gasification

  12. High gradient magnetic beneficiation of dry pulverized coal via upwardly directed recirculating fluidization

    Science.gov (United States)

    Eissenberg, David M.; Liu, Yin-An

    1980-01-01

    This invention relates to an improved device and method for the high gradient magnetic beneficiation of dry pulverized coal, for the purpose of removing sulfur and ash from the coal whereby the product is a dry environmentally acceptable, low-sulfur fuel. The process involves upwardly directed recirculating air fluidization of selectively sized powdered coal in a separator having sections of increasing diameters in the direction of air flow, with magnetic field and flow rates chosen for optimum separations depending upon particulate size.

  13. Ash transformation during co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn;

    2007-01-01

    Co-firing straw with coal in pulverized fuel boilers can cause problems related to fly ash utilization, deposit formation, corrosion and SCR catalyst deactivation due to the high contents of Cl and K in the ash. To investigate the interaction between coal and straw ash and the effect of coal...... quality on fly ash and deposit properties, straw was co-fired with three kinds of coal in an entrained flow reactor. The compositions of the produced ashes were compared to the available literature data to find suitable scaling parameters that can be used to predict the composition of ash from straw...... importantly, by reaction with Al and Si in the fly ash. About 70-80% K in the fly ash appears as alumina silicates while the remainder K is mainly present as sulphate. Lignite/straw co-firing produces fly ash with relatively high Cl content. This is probably because of the high content of calcium...

  14. Recovered fuels - The connection between fuel preparation, combustion equipments and ash quality; Returbraenslen - kopplingen mellan braensleberedning, foerbraenningsutrustning och askkvalitet

    Energy Technology Data Exchange (ETDEWEB)

    Gyllenhammar, Marianne; Johansson, Inge [S.E.P. Scandinavian Energy Project AB, Goeteborg (Sweden)

    2004-01-01

    The lack of bio fuel and new regulations of waste treatment have increased the interest of recovered fuels. Co-combustion is of great interest, but the consequences and permit handling involved in introducing a new fuel into a plant have to be investigated. The aim of this study is to see if it is possible to affect the ash quality by pre-treatment of the fuel, or by firing in different combustion equipments. Ashes can be used in several different types of applications. Few of these have uniform requirements of ash quality. The ongoing research will hopefully help generating unified regulations and recommendations for the uses of ashes. However, right now the knowledge is limited and very specific. Every type of ash has to be analysed for the appropriate use. It is especially the requirements of leaching that are difficult to make general. The work started with a survey of recovered fuels. It contains roughly which fuels exist and which of those are accessible for the energy market in Sweden. The survey showed that there are approximately 13 Mton/y wastes partly accessible to the energy market; 50 % are used for material recycling, 32 % for energy recovery, 1.5 % for composting and the rest are used as landfill. Three recovered fuels were chosen and studied more thoroughly. These were PTP (paper, wood and plastic), tires and impregnated wood. The project showed that the recovered fuels have different qualifications as fuels and have different possibilities at co-combustion which results in variable ash quality. A pre-treated fuel is more homogeneous which give better combustion and cleaner ashes. A fluidised bed demands a more pre-treated fuel than a grate and the fluidised bed generate more ashes because the ashes contain bed material. As a result of this the ashes from a fluidised bed is generally easier to utilize. In this project the composition of ashes from co-combustion of the three recovered fuels together with wood fuel has been estimated. The aim was to

  15. Wood fuel quality of two Salix viminalis stands fertilised with sludge, ash and sludge-ash mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Adler, Anneli [Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7043, SE-750 07 Uppsala (Sweden); Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Riia 181, 51014 Tartu (Estonia); Dimitriou, Ioannis; Aronsson, Paer; Verwijst, Theo; Weih, Martin [Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7043, SE-750 07 Uppsala (Sweden)

    2008-10-15

    This study assessed the effects of stand structure and fertilisation with wood ash and/or sludge on wood fuel quality of Salix viminalis. The relative proportions of bark and wood in 1-, 2- and 3-year-old shoot populations were determined. The concentrations of essential elements (N, P, K) and heavy metals (Cu, Zn, Cd, Ni) in bark and wood were used to assess the wood fuel quality in harvestable shoot biomass. Controlled field experiments were conducted on two newly harvested commercial short-rotation willow coppice fields. Five treatments were applied: sewage sludge at the maximum legally permitted amount; ash; two sludge-ash mixtures supplying the maximum and twice the maximum permitted sludge-ash amount; and a control receiving mineral nutrients only. The proportion of bark in the willow stands was decreasing with the age of the shoot population. The shoot population with few large stems, compared to that with many small stems, had a lower proportion of element-rich bark in the harvestable shoot biomass, meaning better quality of the wood fuel. Overall, wood fuel quality in terms of mineral concentrations was influenced by the age of the shoot population at harvest, stand structure, management practices (e.g. planting density, fertilisation) and site conditions (soil type, element availability). Our results imply that harvestable shoot biomass of willows grown as few large stems have better wood fuel quality, compared to harvestable shoot biomass of many small stems. Increased length of cutting cycle improves the wood fuel quality. (author)

  16. FUNDAMENTAL INVESTIGATION OF FUEL TRANSFORMATIONS IN PULVERIZED COAL COMBUSTION AND GASIFICATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Joseph Calo; Thomas Fletcher; Alan Sayre

    2003-01-01

    The goal of this project is to carry out the necessary experiments and analyses to extend leading submodels of coal transformations to the new conditions anticipated in next-generation energy technologies. During the first project quarter, a technical kick-off meeting was held on the Brown campus involving PIs from Brown (Hurt, Calo), BYU (Fletcher), and B&W (Sayre, Burge). Following this first meeting the current version of CBK (Version 8) was transferred to B&W McDermott and the HP-CBK code developed by BYU was transferred to Brown to help guide the code development in this project. Also during the first project year, progress was reviewed at an all-hands meeting was held at Brigham Young University in August, 2001. The meeting was attended by PIs Fletcher, Hurt, Calo, and Sayre, and also by affiliated investigators Steven Burge from McDermott and Prof. William Hecker from BYU. During the first project year, significant progress was made on several fronts, as described in detail in the previous annual report. In the current second annual report, we report on progress made on two important project tasks. At Brown University: (1) Char combustion reactivities at 500 C in air were determined for a diverse set of solid fuels and organic model compound chars. These varied over 4 orders of magnitude for the chars prepared at 700 C, and over 3 orders of magnitude for the chars prepared at 1000 C. The resultant reactivities correlate poorly with organic elemental composition and with char surface area. (2) Specially-acquired model materials with minute amounts of inorganic matter exhibit low reactivities that fall in a narrow band as a function of wt-% carbon. Reactivities in this sample subset correlate reasonably well with total char surface area. (3) A hybrid chemical/statistical model was developed which explains most of the observed reactivity variation based on four variables: the amounts of nano-dispersed K, nanodispersed (Ca+Mg), elemental carbon (wt-% daf), and

  17. Durability Properties of Palm Oil Fuel Ash Self Compacting Concrete

    Directory of Open Access Journals (Sweden)

    T. Ofuyatan

    2015-02-01

    Full Text Available Self Compacting Concrete (SCC is a new innovation in technology that can flow readily into place under its own self weight and fill corner areas of reinforcement structures without the need to vibrate and without segregation of its constitute. The problem of durability of concrete structures due to inadequate compaction by skilled workers has become a source of concern globally. The shortage of skilled manpower, noise and vibration of equipment on construction sites has led to the development of self compacting concrete. This paper presents an experimental study on the durability properties of Self Compacting Concrete with partial placement of Palm Oil Fuel Ash (POFA. Twelve POFA self-compacting concretes of various strength grades were designed at varying percentages of 0, 5, 10, 15, 20, 25 and 30%. The concrete with no placement of ash served as control. Conplast SP432MS was used as superplasticiser in the mix. The experiments are carried out by adopting a water-powder ratio of 0.36. Workability of the fresh concrete is determined by using tests such as: slump flow, T50, V-funnel and L-Box tests. The durability of concrete is tested by acid resistance, sulphate attack and saturated water absorption at the age of 14, 28, 56 and 90 days.

  18. Physicochemical characterizations of nano-palm oil fuel ash

    Energy Technology Data Exchange (ETDEWEB)

    Rajak, Mohd Azrul Abdul, E-mail: azrulrajak88@gmail.com [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia); Preparatory Centre of Science and Technology, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah (Malaysia); Majid, Zaiton Abdul, E-mail: zaiton@kimia.fs.utm.my [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia); Ismail, Mohammad [Department of Structure and Material, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia)

    2015-07-22

    Palm Oil Fuel Ash (POFA) is known as a good supplementary cementing material due to its siliceous-rich content. The application of nanotechnology in the pozzolanic materials could invent new functions in the efficiency of physical and chemical properties of materials. Thus, the present study aims to generate nano-sized POFA and characterize the physicochemical properties of nano-palm oil fuel ash (nPOFA). The nPOFA was prepared by mechanically grinding micro POFA using a high intensity ball milling for 6 hours. The physicochemical properties of nPOFA were characterized via X-Ray Fluoresence (XRF), Scanning Emission microscopy- Energy Dispersive X-Ray (SEM-EDX), Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD). The particle size of nPOFA acquired from TEM analysis was in the range of 20 nm to 90 nm, while the average crystallite size calculated from XRD diffractogram was 61.5 nm. The resulting nPOFA has a BET surface area of 145.35 m{sup 2}/g, which is more than 85% increment in surface area compared to micro-sized POFA. The morphology and elemental studies showed the presence of spherical as well as irregularly shaped and fine nPOFA particles contains with high silicon content. The presence of α-quartz as the major phase of the nPOFA was identified through XRD analysis. The study concludes that nPOFA has the potential as a supplementary cementing material due to the high silica content, high surface area and the unique behaviors of nano-structured particles.

  19. Formation of fine particles in co-combustion of coal and solid recovered fuel in a pulverized coal-fired power station

    DEFF Research Database (Denmark)

    Wu, Hao; Pedersen, Anne Juul; Glarborg, Peter

    2011-01-01

    Fine particles formed from combustion of a bituminous coal and co-combustion of coal with 7 th% (thermal percentage) solid recovered fuel (SRF) in a pulverized coal-fired power plant were sampled and characterized in this study. The particles from dedicated coal combustion and co-combustion both...... appear to be an important formation mechanism. The elemental composition of the particles from coal combustion showed that S and Ca were significantly enriched in ultrafine particles and P was also enriched considerably. However, compared with supermicron particles, the contents of Al, Si and K were...

  20. Modern power station practice mechanical boilers, fuel-, and ash-handling plant

    CERN Document Server

    Sherry, A; Cruddace, AE

    2014-01-01

    Modern Power Station Practice, Second Edition, Volume 2: Mechanical (Boilers, Fuel-, and Ash-Handling Plant) focuses on the design, manufacture and operation of boiler units and fuel-and ash-handling plants.This book is organized into five main topics-furnace and combustion equipment, steam and water circuits, ancillary plant and fittings, dust extraction and draught plant, and fuel-and ash-handling plant.In these topics, this text specifically discusses the influence of nature of coal on choice of firing equipment; oil-burner arrangements, ignition and control; disposition of the heating surf

  1. Chemical composition and properties of ashes from combustion plants using Miscanthus as fuel.

    Science.gov (United States)

    Lanzerstorfer, Christof

    2017-04-01

    Miscanthus giganteus is one of the energy crops considered to show potential for a substantial contribution to sustainable energy production. In the literature there is little data available about the chemical composition of ashes from the combustion of Miscanthus and practically no data about their physical properties. However, for handling, treatment and utilization of the ashes this information is important. In this study ashes from two biomass combustion plants using Miscanthus as fuel were investigated. The density of the ashes was 2230±35kg/m(3), which was similar to the density of ashes from straw combustion. Also the bulk densities were close to those reported for straw ashes. The flowability of the ashes was a little worse than the flowability of ashes from wood combustion. The measured heavy metal concentrations were below the usual limits for utilization of the ashes as soil conditioner. The concentrations in the bottom ash were similar to those reported for ash from forest residue combustion plants. In comparison with cyclone fly ashes from forest residue combustion the measured heavy metal concentrations in the cyclone fly ash were considerably lower. Cl(-), S and Zn were enriched in the cyclone fly ash which is also known for ashes from wood combustion. In comparison with literature data obtained from Miscanthus plant material the concentrations of K, Cl(-) and S were lower. This can be attributed to the fact that the finest fly ash is not collected by the cyclone de-dusting system of the Miscanthus combustion plants. Copyright © 2016. Published by Elsevier B.V.

  2. Characterisation of ashes produced by co-combustion of recovered fuels and peat

    Energy Technology Data Exchange (ETDEWEB)

    Frankenhaeuser, M. [Borealis Polymers Oy, Porvoo (Finland)

    1997-10-01

    The current project focuses on eventual changes in ash characteristics during co-combustion of refuse derived fuel with coal, peat, wood or bark, which could lead to slagging, fouling and corrosion in the boiler. Ashes were produced at fluidised bed (FB) combustion conditions in the 15 kW reactor at VTT Energy, Jyvaeskylae, the fly ash captured by the cyclone was further analysed by XRF at Outokumpu Geotechnical Laboratory, Outokumpu. The sintering behaviour of these ashes was investigated using a test procedure developed at the Combustion Chemistry Research Group at Aabo Akademi University. The current extended programme includes a Danish refuse-derived fuel (RDF), co-combusted with bark/coal (5 tests) and wood/coal (2 tests), a RF from Jyvaskyla (2 tests with peat/coal) and de-inking sludges co- combusted at full-scale with wood waste or paper mill sludge (4 ashes provided by IVO Power). Ash pellets were thermally treated in nitrogen in order to avoid residual carbon combustion. The results obtained show no sintering tendencies below 600 deg C, significant changes in sintering are seen with pellets treated at 1000 deg C. Ash from 100 % RDF combustion does not sinter, 25 % RDF co-combustion with wood and peat, respectively, gives an insignificant effect. The most severe sintering occurs during co-combustion of RDF with bark. Contrary to the earlier hypothesis a 25 % coal addition seems to have a negative effect on all fuel blends. Analysis of the sintering results versus ash chemical composition shows, that (again), in general, an increased level of alkali chlorides and sulphates gives increased sintering. Finally, some results on sintering tendency measurements on ashes from full-scale CFB co-combustion of deinking sludge with wood waste and paper mill sludge are given. This shows that these ashes show very little, if any, sintering tendency, which can be explained from ash chemistry

  3. Effects of co-combustion of secondary fuels on fly ash quality

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, F.J.M.; Vissers, J.L.J.; Van den Berg, J.W. [Dutch Fly Ash Corp., (Netherlands)

    2001-07-01

    In 1995, the Netherlands considered using secondary fuels in combination with hard coal for power generation. This decision was based on both economic and environmental advantages of co-combustion of secondary fuels. The combustion of non-fossil fuels results in lower carbon dioxide emissions into the atmosphere. Initially, the Dutch government only allowed 10 per cent co-combustion of secondary fuels, but in 2000, higher percentages were allowed in favour of decreasing fossil carbon dioxide production. This paper presented the results of a complete characterization of fly ashes. In particular, to show whether the quality of fly ash was affected by co-combustion, the technical and environmental quality of concrete with fly ash was evaluated in comparison to the quality of concrete with reference fly ashes. Fly ashes from co-combustion showed no significant changes in chemical composition from their reference ashes, except for the calcium oxide contents of PA10 and the phosphate content of RWZI. Fly ashes from co-combustion were found to be enriched in trace elements. The secondary fuels that were considered besides fly ash were wood, poultry, litter, sewage sludge, coffee grounds, and cocoa shells. These all contribute to lowering the emissions of fossil carbon dioxide because they all contain short cycle carbon dioxide. Co-combustion is viewed as a way for coal fired plants in the Netherlands to reach the targets of the Kyoto Agreement on climate change. European legislation is in preparation to make utilization of fly ashes from co-combustion possible. 7 refs., 9 tabs., 8 figs.

  4. Dating and sourcing fuel ash residues from Cladh Hallan, South Uist, Scotland, using magnetic techniques

    Science.gov (United States)

    Peters, C.; Batt, C. M.

    Mineral magnetic and archaeomagnetic measurements have been carried out on fire ash deposits from a central hearth within a circular dwelling at the Late Bronze/Early Iron Age settlement site of Cladh Hallan on South Uist, Scotland. Archaeomagnetic methods date the hearths to 560-700 BC and 650-850 BC, the earliest archaeomagnetic dates produced for the Western Isles of Scotland. A range of mineral magnetic measurements have been carried out on a continually sampled profile through the hearths/ash build-ups displaying differences between the two main ash build-ups and floors. The mineral magnetic results have also been used to assess fuel sources through the application of techniques based on modern ash residues. The results show a marked change in fuel source from well-humified peat to a more mixed fuel, with a high proportion of fibrous-upper peat/peat turf.

  5. Pyrolysis and Combustion of Pulverized Wheat Straw in a Pressurized Entrained Flow Reactor

    DEFF Research Database (Denmark)

    Fjellerup, Jan Søren; Gjernes, Erik; Hansen, Lars Kresten

    1996-01-01

    Within the past decade, there has been an interest for pressurized combustion and gasification of solid fuels in power plants due to the potential for high efficiency. The utilization of new types of solid fuels for pressurized combustion and gasification depends on char yield and char reactivity...... at relevant conditions. The pressurized entrained now reactor designed at Rise is introduced. Pyrolysis and combustion at 10 and 20 bar pressure have been studied using pulverized wheat straw. Samples of partly reacted particles are collected, and the conversion is calculated using the ash tracer technique...

  6. High ash fuels for diesel engines II; Korkean tuhkapitoisuuden omaavan polttoaineen kaeyttoe dieselvoimaloissa II

    Energy Technology Data Exchange (ETDEWEB)

    Norrmen, E.; Vestergren, R.; Svahn, P. [Wartsila Diesel International Ltd, Vaasa (Finland)

    1996-12-01

    Heavy fuel oils containing a large amount of ash, that is used in some geographically restricted areas, can cause problems with deposit formation and hot corrosion, leading to burned exhaust gas valves in some diesel engines. The Liekki 2 programs Use of high ash fuel in diesel power plants I and II have been initiated to clarify the mechanisms of deposit formation, and start and propagation of hot corrosion. The aim is to get enough knowledge to enable the development of the Waertsilae diesel engines to be able to handle heavy fuel with a very high ash content. The chemistry, sintering, melting, and corrosiveness of deposits from different part of the diesel engine and on different exhaust valve materials, as well as the chemistry in different depths of the deposit have been investigated. Theories for the mechanisms mentioned above have been developed. Additives changing the sintering/melting point and physical properties of the formed deposits have been screened. Exhaust gas particle measurements have been performed when running on high ash fuel, both without deposit modifying fuel additive and with. The results have been used to verify the ABC (Aerosol Behaviour in Combustion) model, and the particle chemistry and morphology has been examined. Several tests, also high load endurance tests have been run in diesel engines with high ash fuels. (author)

  7. Ignition et oxydation des particules de combustible solide pulvérisé Ignition and Oxidation of Pulverized Solid Fuel

    Directory of Open Access Journals (Sweden)

    De Soete G. G.

    2006-11-01

    élais d'ignition ont été déterminés pour un grand nombre de combustibles solides de rang inférieur et supérieur (charbons, cokes, asphaltènes, suies, bois, graphite. L'étude de la vitesse expérimentale de la combustion hétérogène, notamment l'étude de la température apparente d'activation, et sa dépendance par rapport à la taille des particules et à la concentration d'oxygène, montre que, dans les conditions des essais, cette combustion est contrôlée par la désorption du CO et se déroule principalement en régime cinético-diffusionnel mixte. L'étude de la dépendance des délais d'ignition par rapport à la température, la taille des particules et la pression partielle d'oxygène, suggère que, pendant ces délais, les réactions se déroulent en régime cinétique pur et que le produit des réactions de désorption est principalement le CO. The heated-grid method is used to investigate the competition between (1 the devolatilization and subsequent oxidation of pyrolysis products and (2 the ignition of the solid matrix and its rapid combustion. A comparison between the instant of ignition and the start of pyrolysis is used to determine the range in which ignition of a pyrolyzable solid fuel of the whole coal ignitiontype (i. e. when ignition occurs before pyrolysis becomes measurable occurs as a function of temperature, particle size and oxygen concentration. The results suggest that this type of ignition might occur, as a general rule, under conditions involving pulverized solid fuels in industrial flames. In the case of whole coalignition, the rate of combustion of the solid matrix is inhibited during the period following ignition. This inhibition is due partly to the difficulty oxygen has of spreading through the pores during the discharge of pyrolysis products and partly to preferential oxygen consumption during the oxidation of pyrolysis products, mainly when this oxidation develops in the form of flames. t is only when pyrolysis ends that

  8. NOx control in large-scale power plant boilers through superfine pulverized coal technology

    Institute of Scientific and Technical Information of China (English)

    Jie YIN; Jianxing REN; Dunsong WEI

    2008-01-01

    Superfine pulverized coal technology can effectively reduce NOx emission in coal-fired power plant boilers. It can also economize the cost of the power plant and improve the use of the ash in the flue gas. Superfine pulverized coal technology, which will be widely used in China, includes common superfine pulverized coal technology and superfine pulverized coal reburning technology. The use of superfine pulver-ized coal instead of common coal in large-scale power plants will not only reduce more than 30% of NOx emission but also improve the thermal efficiency of the boiler.

  9. Development and numerical/experimental characterization of a lab-scale flat flame reactor allowing the analysis of pulverized solid fuel devolatilization and oxidation at high heating rates

    Science.gov (United States)

    Lemaire, R.; Menanteau, S.

    2016-01-01

    This paper deals with the thorough characterization of a new experimental test bench designed to study the devolatilization and oxidation of pulverized fuel particles in a wide range of operating conditions. This lab-scale facility is composed of a fuel feeding system, the functioning of which has been optimized by computational fluid dynamics. It allows delivering a constant and time-independent mass flow rate of fuel particles which are pneumatically transported to the central injector of a hybrid McKenna burner using a carrier gas stream that can be inert or oxidant depending on the targeted application. A premixed propane/air laminar flat flame stabilized on the porous part of the burner is used to generate the hot gases insuring the heating of the central coal/carrier-gas jet with a thermal gradient similar to those found in industrial combustors (>105 K/s). In the present work, results issued from numerical simulations performed a priori to characterize the velocity and temperature fields in the reaction chamber have been analyzed and confronted with experimental measurements carried out by coupling particle image velocimetry, thermocouple and two-color pyrometry measurements so as to validate the order of magnitude of the heating rate delivered by such a new test bench. Finally, the main features of the flat flame reactor we developed have been discussed with respect to those of another laboratory-scale system designed to study coal devolatilization at a high heating rate.

  10. Development and numerical/experimental characterization of a lab-scale flat flame reactor allowing the analysis of pulverized solid fuel devolatilization and oxidation at high heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, R., E-mail: romain.lemaire@mines-douai.fr; Menanteau, S. [Mines Douai, EI, F-59508 Douai (France)

    2016-01-15

    This paper deals with the thorough characterization of a new experimental test bench designed to study the devolatilization and oxidation of pulverized fuel particles in a wide range of operating conditions. This lab-scale facility is composed of a fuel feeding system, the functioning of which has been optimized by computational fluid dynamics. It allows delivering a constant and time-independent mass flow rate of fuel particles which are pneumatically transported to the central injector of a hybrid McKenna burner using a carrier gas stream that can be inert or oxidant depending on the targeted application. A premixed propane/air laminar flat flame stabilized on the porous part of the burner is used to generate the hot gases insuring the heating of the central coal/carrier-gas jet with a thermal gradient similar to those found in industrial combustors (>10{sup 5} K/s). In the present work, results issued from numerical simulations performed a priori to characterize the velocity and temperature fields in the reaction chamber have been analyzed and confronted with experimental measurements carried out by coupling particle image velocimetry, thermocouple and two-color pyrometry measurements so as to validate the order of magnitude of the heating rate delivered by such a new test bench. Finally, the main features of the flat flame reactor we developed have been discussed with respect to those of another laboratory-scale system designed to study coal devolatilization at a high heating rate.

  11. Modeling and full-scale tests of vortex plasma-fuel systems for igniting high-ash power plant coal

    Science.gov (United States)

    Messerle, V. E.; Ustimenko, A. B.; Karpenko, Yu. E.; Chernetskiy, M. Yu.; Dekterev, A. A.; Filimonov, S. A.

    2015-06-01

    The processes of supplying pulverized-coal fuel into a boiler equipped with plasma-fuel systems and its combustion in the furnace of this boiler are investigated. The results obtained from 3D modeling of conventional coal combustion processes and its firing with plasma-assisted activation of combustion in the furnace space are presented. The plasma-fuel system with air mixture supplied through a scroll is numerically investigated. The dependence of the swirled air mixture flow trajectory in the vortex plasma-fuel system on the scroll rotation angle is revealed, and the optimal rotation angle at which stable plasma-assisted ignition of pulverized coal flame is achieved is determined.

  12. Quantification of fusion in ashes from solid fuel combustion

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug; Frandsen, Flemming; Dam-Johansen, Kim

    1999-01-01

    . Using STA, melting is detected as an endothermic reaction involving no change in mass. The measurement signals are transferred into a fusion curve showing the melt fraction in the ash as a function of temperature. This is done either by a simple comparison of the energies used for melting in different...

  13. Recycling of ash - an important factor in the forest fuel cycle; Askaaterfoering - en viktig faktor i skogsbraenslets kretslopp

    Energy Technology Data Exchange (ETDEWEB)

    Lundborg, A.

    1997-12-31

    If energy sources are to be called renewable, they must be used on the conditions set by nature and natural balance must be maintained. The ash from biofuels from forests contains almost all the minerals and nutrients (except nitrogen) which were present in the fuel and should be recycled to the forest. This conference paper describes the composition and properties of ash, its production and handling, and its ecological effects when recycled. The chemical properties of ash depend largely on the content of minerals, nutrients and heavy metals in the fuel, and on how the combustion process is conducted. Ash from bioforests or from waste combustion may contain heavy metals and may be unsuitable for recycling. Ash is strongly alkaline and needs processing before recycling. In forests that grow on peat the addition of ash causes a strong growth of trees. On firm ground, however, the effect of adding ash is more in the nature of long-time forest care. 4 refs.

  14. Thermal and Ash Characterization of Indonesian Bamboo and Its Potential for Solid Fuel and Waste Valorization

    Directory of Open Access Journals (Sweden)

    Aprilina Purbasari

    2016-08-01

    Full Text Available Bamboo has been widely used in Indonesia for construction, handicrafts, furniture and other uses. However, the use of bamboo as a biomass for renewable energy source has not been extensively explored. This paper describes the thermal and ash characterization of three bamboo species found in Indonesia, i.e. Gigantochloa apus, Gigantochloa levis and Gigantochloa atroviolacea. Characterization of bamboo properties as a solid fuel includes proximate and ultimate analyses, calorific value measurement and thermogravimetric analysis. Ash characterization includes oxide composition analysis and phase analysis by X-Ray diffraction. The selected bamboo species have calorific value comparable with wood with low nitrogen and sulphur contents, indicating that they can be used as renewable energy sources. Bamboo ash contains high silicon so that bamboo ash has potential to be used further as building materials or engineering purposes. Ash composition analysis also indicates high alkali that can cause ash sintering and slag formation in combustion process. This implies that the combustion of bamboo requires the use of additives to reduce the risk of ash sintering and slag formation. Article History: Received May 15, 2016; Received in revised form July 2nd, 2016; Accepted July 14th, 2016; Available online How to Cite This Article: Purbasari, A., Samadhi, T.W. & Bindar, Y. (2016 Thermal and Ash Characterization of Indonesian Bamboo and its Potential for Solid Fuel and Waste Valorization. Int. Journal of Renewable Energy Development, 5(2, 95-100. http://dx.doi.org/10.14710/ijred.5.2.96-100 

  15. Volcanic ash fuels anomalous plankton bloom in subarctic northeast Pacific

    Science.gov (United States)

    Hamme, Roberta C.; Webley, Peter W.; Crawford, William R.; Whitney, Frank A.; DeGrandpre, Michael D.; Emerson, Steven R.; Eriksen, Charles C.; Giesbrecht, Karina E.; Gower, Jim F. R.; Kavanaugh, Maria T.; Peña, M. Angelica; Sabine, Christopher L.; Batten, Sonia D.; Coogan, Laurence A.; Grundle, Damian S.; Lockwood, Deirdre

    2010-10-01

    Using multiple lines of evidence, we demonstrate that volcanic ash deposition in August 2008 initiated one of the largest phytoplankton blooms observed in the subarctic North Pacific. Unusually widespread transport from a volcanic eruption in the Aleutian Islands, Alaska deposited ash over much of the subarctic NE Pacific, followed by large increases in satellite chlorophyll. Surface ocean pCO2, pH, and fluorescence reveal that the bloom started a few days after ashfall. Ship-based measurements showed increased dominance by diatoms. This evidence points toward fertilization of this normally iron-limited region by ash, a relatively new mechanism proposed for iron supply to the ocean. The observations do not support other possible mechanisms. Extrapolation of the pCO2 data to the area of the bloom suggests a modest ˜0.01 Pg carbon export from this event, implying that even large-scale iron fertilization at an optimum time of year is not very efficient at sequestering atmospheric CO2.

  16. Investigations of ash fouling with cattle wastes as reburn fuel in a small-scale boiler burner under transient conditions.

    Science.gov (United States)

    Oh, Hyukjin; Annamalai, Kalyan; Sweeten, John M

    2008-04-01

    Fouling behavior under reburn conditions was investigated with cattle wastes (termed as feedlot biomass [FB]) and coal as reburn fuels under a transient condition and short-time operation. A small-scale (30 kW or 100,000 Btu/hr) boiler burner research facility was used for the reburn experiments. The fuels considered for these experiments were natural gas (NG) for the ashless case, pure coal, pure FB, and blends of coal and FB. Two parameters that were used to characterize the ash "fouling" were (1) the overall heat-transfer coefficient (OHTC) when burning NG and solid fuels as reburn fuels, and (2) the combustible loss through ash deposited on the surfaces of heat exchanger tubes and the bottom ash in the ash port. A new methodology is presented for determining ash-fouling behavior under transient conditions. Results on the OHTCs for solid reburn fuels are compared with the OHTCs for NG. It was found that the growth of the layer of ash depositions over longer periods typically lowers OHTC, and the increased concentration of ash in gas phase promotes radiation in high-temperature zones during initial periods while decreasing the heat transfer in low-temperature zones. The ash analyses indicated that the bottom ash in the ash port contained a smaller percentage of combustibles with a higher FB percentage in the fuels, indicating better performance compared with coal because small particles in FB burn faster and the FB has higher volatile matter on a dry ash-free basis promoting more burn out.

  17. A review of the interference of carbon containing fly ash with air entrainment in concrete

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard; Jensen, Anker Degn; Skjøth-Rasmussen, Martin Skov;

    2008-01-01

    Industrial utilization of fly ash from pulverized coal combustion plays an important role in environmentally clean and cost effective power generation. Today, the primary market for fly ash utilization is as pozzolanic additive in the production of concrete. However, the residual carbon in fly ash...... on the adsorption capacity of AEAs. The type of fuel used in the combustion process influences the amount and properties of the residual carbon. Fly ash derived from bituminous coal has generally higher carbon content compared with fly ash produced from subbituminous coal or lignite, but shows a lower AEA......-treatment methods applied to improve fly ash quality are described in the review. Ozonation, thermal treatment and physical cleaning of carbon have been found to improve the fly ash performance for concrete utilization. Ultimately, recommendations for further work are outlined in the discussion....

  18. Comparison of various bioassays for dioxins measurements in fuel gas, fly ash and bottom ash

    Energy Technology Data Exchange (ETDEWEB)

    Ota, S.; Kin-ichi, S. [Ministry of the Environment, Tokyo (Japan); Masatoshi, M.; Shin-ichi, S. [National Institute for Environmental Studies, Tsukuba (Japan)

    2004-09-15

    In Japan, the control standards for dioxins (PCDDs, PCDFs and Co-PCBs) in the emission gas, fly and bottom ashes from waste incinerators have been defined in the Law Concerning Special Measures against Dioxins (Dioxins Law). Based on the Dioxins law, an installation personnel of waste incinerators of specified facilities shall measure dioxins in the emission gas and fly and bottom ashes more than once every year followed by reporting the results to their prefectural governor. The present regulating procedure has been set to use high-resolution gas chromatography/ high-resolution mass spectrometry (HRGC/HRMS, hereafter GC/MS) systems to determine dioxin-concentrations. However, the GC/MS measurements are often money- and timeconsuming, since they need complicated steps for sample preparation, expensive equipments and highly skilled technicians. Therefore, it is of high priority to develop rapid and economical alternative methods to measure dioxins. Recently, various assays using biological reactions have drawn a high degree of attention as a candidate for alternative measurement methods of dioxins. During the past decade several studies demonstrated the utility of a chemical (GC/MS) and biological (bioassays/biomarkers) control of waste thermal recycling processes like pyrolysis or incineration treatment. In this paper, we report the results of our recent examinations on the possibility to apply various bioassays to supplementary methods for the present procedure.

  19. The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

    Science.gov (United States)

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-12-01

    The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides

  20. CFD modeling of ash deposition for co-combustion of MBM with coal in a tangentially fired utility boiler

    NARCIS (Netherlands)

    Taha, T.J.; Stam, A.F.; Stam, K.; Brem, G.

    2013-01-01

    Ash deposition is one of the main challenges that needs to be tackled in response to increased percentage of biomass co-firing in pulverized fuel boilers. In this study, a model has been developed to investigate the slagging behavior of meat and bone meal (MBM) at higher co-firing rates in the Maasv

  1. COMPARISON OF PARTICLE SIZE DISTRIBUTIONS AND ELEMENTAL PARTITIONING FROM THE COMBUSTION OF PULVERIZED COAL AND RESIDUAL FUEL OIL

    Science.gov (United States)

    The paper gives results of experimental efforts in which three coals and a residual fuel oil were combusted in three different systems simulating process and utility boilers. Particloe size distributions (PSDs) were determined using atmospheric and low-pressure impaction, electr...

  2. Use of high ash fuel in diesel power plants II; Korkean tuhkapitoisuuden omaavan polttoaineen kaeyttoe dieselvoimaloissa II

    Energy Technology Data Exchange (ETDEWEB)

    Vestergren, R.; Normen, E.; Hellen, G. [Wartsila Diesel International Ltd Oy, Vaasa (Finland)] [and others

    1997-10-01

    Heavy fuel oils containing a large amount of ash are used in some geographically restricted areas. The ash components can cause problems with deposit formation and hot corrosion, leading to burned exhaust gas valves in some diesel engines. The LIEKKI 2 programs Use of high ash fuel in diesel power plants, Part I and II, have been initiated to clarify the mechanisms of deposit formation, and start and propagation of hot corrosion. The aim is to get enough knowledge to enable the development of the Waertsilae diesel engines to be able to handle heavy fuels with a very high ash content. The chemistry during combustion has been studied. The chemical and physical properties of the particles in the exhaust gas, of the deposits, and of exhaust valves have been investigated. Exhaust gas particle measurements have been performed when running on high ash fuel, both with and without deposit modifying fuel additive. Theories for the mechanisms mentioned above have been developed. On the practical side two long time field tests are going on, one with an ash/deposit modifying fuel additive (vanadium chemistry alteration), one with fuel water washing (sodium removal). Seven different reports have been written. (orig.)

  3. Characterization of ashes from a 100 kWth pilot-scale circulating fluidized bed with oxy-fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.H.; Wang, C.B.; Tan, Y.W.; Jia, L.F.; Anthony, E.J. [Natural Resources Canada, Ottawa, ON (Canada)

    2011-09-15

    Oxy-fuel combustion experiments have been carried out on an oxygen-fired 100 kW(th) mini-circulating fluidized bed combustion (CFBC) facility. Coal and petroleum coke were used as fuel together with different limestones (and fixed Ca:S molar ratios) premixed with the fuel, for in situ SO{sub 2} capture. The bed ash (BA) and fly ash (FA) samples produced from this unit were collected and characterized to obtain physical and chemical properties of the ash samples. The characterization methods used included X-ray fluorescence (XRF), X-ray diffraction (XRD), char carbon and free lime analysis, thermogravimetric analysis (TGA), and surface analysis. The main purpose of this work is to characterize the CFBC ashes from oxy-fuel firing to obtain a better understanding of the combustion process, and to identify any significant differences from the ash generated by a conventional air-fired CFBC. The primary difference in the sulfur capture mechanism between atmospheric air-fired and oxy-fuel FBC, at typical FBC temperatures (similar to 850{sup o}C), is that, in the air-fired case the limestone sorbents calcine, whereas the partial pressure of CO{sub 2} in oxy-fuel FBC is high enough to prevent calcination, and hence the sulfation process should mimic that seen in pressurized FBC (PFBC). Here, the char carbon content in the fly ash was much higher than that in the bed ash, and was also high by comparison with ash obtained from conventional commercial air-firing CFBC units. In addition, measurements of the free lime content in the bed and fly ash showed that the unreacted Ca sorbent was present primarily as CaCO{sub 3}, indicating that sulfur capture in the oxy-fuel combustor occurred via direct sulfation.

  4. Exploratory Study of Palm Oil Fuel Ash as Partial Cement Replacement in Oil Palm Shell Lightweight Aggregate Concrete

    OpenAIRE

    Muthusamy, K.; Z. Nur Azzimah

    2014-01-01

    In Malaysia, issue of environmental pollution resulting from disposal of Palm Oil Fuel Ash (POFA) which is a by-product from palm oil mill has initiated research to incorporate this waste in Oil Palm Shell (OPS) lightweight aggregate concrete production. The current study investigates the effect of palm oil fuel ash content as partial cement replacement towards compressive strength OPS lightweight aggregate concrete. Several OPS lightweight aggregate concrete mixes were produced by replacing ...

  5. Effect of Particle Size Distribution on Wall Heat Flux in Pulverized-Coal Furnaces and Boilers

    Science.gov (United States)

    Lu, Jun

    A mathematical model of combustion and heat transfer within a cylindrical enclosure firing pulverized coal has been developed and tested against two sets of measured data (one is 1993 WSU/DECO Pilot test data, the other one is the International Flame Research Foundation 1964 Test (Beer, 1964)) and one independent code FURN3D from the Argonne National Laboratory (Ahluwalia and IM, 1992). The model called PILC assumes that the system is a sequence of many well-stirred reactors. A char burnout model combining diffusion to the particle surface, pore diffusion, and surface reaction is employed for predicting the char reaction, heat release, and evolution of char. The ash formation model included relates the ash particle size distribution to the particle size distribution of pulverized coal. The optical constants of char and ash particles are calculated from dispersion relations derived from reflectivity, transmissivity and extinction measurements. The Mie theory is applied to determine the extinction and scattering coefficients. The radiation heat transfer is modeled using the virtual zone method, which leads to a set of simultaneous nonlinear algebraic equations for the temperature field within the furnace and on its walls. This enables the heat fluxes to be evaluated. In comparisons with the experimental data and one independent code, the model is successful in predicting gas temperature, wall temperature, and wall radiative flux. When the coal with greater fineness is burnt, the particle size of pulverized coal has a consistent influence on combustion performance: the temperature peak was higher and nearer to burner, the radiation flux to combustor wall increased, and also the absorption and scattering coefficients of the combustion products increased. The effect of coal particle size distribution on absorption and scattering coefficients and wall heat flux is significant. But there is only a small effect on gas temperature and fuel fraction burned; it is speculated

  6. Fuel, fire and heat: an experimental approach to highlight the potential of studying ash and char remains from archaelological contexts

    NARCIS (Netherlands)

    Braadbaart, F.; Poole, I.; Huisman, H.D.J.; Os, B. van

    2012-01-01

    As in traditional societies today ancient societies probably selected different fuels to meet specific heat requirements. Char and ash, the end products of fire, are often found in abundance in archaeological contexts. These end products can provide information regarding (i) the original fuel resour

  7. Ignition and Combustion of Pulverized Coal and Biomass under Different Oxy-fuel O2/N2 and O2/CO2 Environments

    Science.gov (United States)

    Khatami Firoozabadi, Seyed Reza

    This work studied the ignition and combustion of burning pulverized coals and biomasses particles under either conventional combustion in air or oxy-fuel combustion conditions. Oxy-fuel combustion is a 'clean-coal' process that takes place in O2/CO2 environments, which are achieved by removing nitrogen from the intake gases and recirculating large amounts of flue gases to the boiler. Removal of nitrogen from the combustion gases generates a high CO2-content, sequestration-ready gas at the boiler effluent. Flue gas recirculation moderates the high temperatures caused by the elevated oxygen partial pressure in the boiler. In this study, combustion of the fuels took place in a laboratory laminar-flow drop-tube furnace (DTF), electrically-heated to 1400 K, in environments containing various mole fractions of oxygen in either nitrogen or carbon-dioxide background gases. The experiments were conducted at two different gas conditions inside the furnace: (a) quiescent gas condition (i.e., no flow or inactive flow) and, (b) an active gas flow condition in both the injector and furnace. Eight coals from different ranks (anthracite, semi-snthracite, three bituminous, subbituminous and two lignites) and four biomasses from different sources were utilized in this work to study the ignition and combustion characteristics of solid fuels in O2/N2 or O2/CO2 environments. The main objective is to study the effect of replacing background N2 with CO2, increasing O2 mole fraction and fuel type and rank on a number of qualitative and quantitative parameters such as ignition/combustion mode, ignition temperature, ignition delay time, combustion temperatures, burnout times and envelope flame soot volume fractions. Regarding ignition, in the quiescent gas condition, bituminous and sub-bituminous coal particles experienced homogeneous ignition in both O2/N 2 and O2/CO2 atmospheres, while in the active gas flow condition, heterogeneous ignition was evident in O2/CO 2. Anthracite, semi

  8. Synthesis and characterization of palm oil fuel ash (POFA) and metakaolin based geopolymer for possible application in nanocoating

    Science.gov (United States)

    Khan, Ihsan Ullah; Bhat, A. H.; Masset, Patrick J.; Khan, Farman Ullah; Rehman, Wajid Ur

    2016-11-01

    The main aim of this study was to synthesize and characterize highly amorphous geopolymer from palm oil fuel ash (POFA) and metakaolin, to be used as nanocoating. Geopolymers are man-made aluminosilicate materials that are amorphous analogues of zeolites. The geopolymers were made by condensing a mixture of raw materials metakaolin and palm oil fuel ash (POFA) with alkaline activator at a fixed ratio at room temperature. The kaolin type clay was calcined at 700 °C for 4hrs to transform it into amorphous metakaolin which is more reactive precursor for geopolymer formation. The characteristics of metakaolin and geopolymers (metakaolin and palm oil fuel ash based geopolymers) were analyzed by using x-ray fluorescence (XRF), Fourier transform infra-red spectrometry (FTIR), Thermogravimetric analysis (TG/DTA) and scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDX). FTIR revealed the presence of Al-O and Si-O stretching vibrations of amorphous alumino-silicate structure for metakaolin, palm oil fuel ash and geopolymers. SEM-EDX images showed the presence of reaction product complementary to NASH (N = Na2O, A = Al2O3, S = SiO2, H = H2O) solid. The resulting geopolymers that were synthesized with NaOH/Na2SiO3 solution cured at 60 °C for 3 days. The results demonstrated the suitability of metakaolin and palm oil fuel ash (POFA) for synthesis of geopolymer at room temperatures.

  9. Ash deposition and high temperature corrosion at combustion of aggressive fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hede Larsen, O. [I/S Fynsvaerket, Faelleskemikerne, Odense (Denmark); Henriksen, N. [Elsamprojekt A/S, Faelleskemikerne, Fredericia (Denmark)

    1996-12-01

    In order to reduce CO{sub 2} emission, ELSAM is investigating the possibilities of using biomass - mainly straw - for combustion in high efficiency power plants. As straw has very high contents of chlorine and potassium, a fuel with high corrosion and ash deposition propensities has been introduced. ELSAM has investigated 3 ultra supercritical boiler concepts for combustion of straw alone or together with coal: (1) PF boilers with a relatively low share of straw, (2) CFB boilers with low to high share of straw and (3) vibrating grate boilers with 100% straw. These investigations has mainly been full-scale tests with straw fed into existing boilers. Corrosion tests have been performed in these boilers using temperature regulated probes and in-plant test tubes in existing superheaters. The corrosion has been determined by detailed measurements of wall thickness reduction and light optical microscopic measurements of the material degradation due to high temperature corrosion. Corrosion mechanisms have been evaluated using SEM/EDX together with thermodynamical considerations based on measurements of the chemical environment in the flue gas. Ash deposition is problematic in CFB boilers and in straw fired boilers, especially in years with high potassium and chlorine content of the straw. This ash deposition also is related to condensation of KCl and can probably only be handled by improved cleaning devices. (EG)

  10. Influence of carbonation under oxy-fuel combustion flue gas on the leachability of heavy metals in MSWI fly ash.

    Science.gov (United States)

    Ni, Peng; Xiong, Zhuo; Tian, Chong; Li, Hailong; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2017-09-01

    Due to the high cost of pure CO2, carbonation of MSWI fly ash has not been fully developed. It is essential to select a kind of reaction gas with rich CO2 instead of pure CO2. The CO2 uptake and leaching toxicity of heavy metals in three typical types of municipal solid waste incinerator (MSWI) fly ash were investigated with simulated oxy-fuel combustion flue gas under different reaction temperatures, which was compared with both pure CO2 and simulated air combustion flue gas. The CO2 uptake under simulated oxy-fuel combustion flue gas were similar to that of pure CO2. The leaching concentration of heavy metals in all MSWI fly ash samples, especially in ash from Changzhou, China (CZ), decreased after carbonation. Specifically, the leached Pb concentration of the CZ MSWI fly ash decreased 92% under oxy-fuel combustion flue gas, 95% under pure CO2 atmosphere and 84% under the air combustion flue gas. After carbonation, the leaching concentration of Pb was below the Chinese legal limit. The leaching concentration of Zn from CZ sample decreased 69% under oxy-fuel combustion flue gas, which of Cu, As, Cr and Hg decreased 25%, 33%, 11% and 21%, respectively. In the other two samples of Xuzhou, China (XZ) and Wuhan, China (WH), the leaching characteristics of heavy metals were similar to the CZ sample. The speciation of heavy metals was largely changed from the exchangeable to carbonated fraction because of the carbonation reaction under simulated oxy-fuel combustion flue gas. After carbonation reaction, most of heavy metals bound in carbonates became more stable and leached less. Therefore, oxy-fuel combustion flue gas could be a low-cost source for carbonation of MSWI fly ash. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Ashes from biofuels and mixed fuels - amount and qualities; Askor fraan biobraenslen och blandbraenslen - maengder och kvalitet

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem, Henrik; Ilskog, Elisabeth; Berg, Magnus [AaF Energikonsult AB, Stockholm (Sweden)

    2003-04-01

    In this study, ashes from biofuels used in the energy utilities, the pulp and paper industry and the wood-working industries have been inventoried. The selection of plants to which enquiries were addressed consists of about 50 utilities, all pulp and paper plants and about 20 wood-working industries (e.g. sawmills). The purpose of the study was to estimate the quantities of bio ashes that are recycled to the forests and those that could be recycled. The background to this study is that logging slash is harvested from ca 30,000 ha per year, while ash is recycled only to 2 to 4,000 ha per year. A working hypothesis has been that logging slash or clean wooden fuels are mixed with other fuels to such an extent that the ash is too contaminated to be recycled. The consequence would be that there is a shortage of suitable ash. Therefore, it was desirable that motives for mixing fuels be chartered. In Sweden, approximately one million ton ashes are produced each year and the share of the three industries that have been studied is estimated as: 200 - 340,000 tons from utilities about 275,000 tons from the pulp and paper industry and 100,000 tons from the woodworking industry. These quantities include unburned carbon, water added when the ash is extracted from the boilers etc. Additional quantities of ash are those produced by waste combustion (447,000 tons), wood-burning in residential buildings (50 - 100,000 tons) etc. In all, ash that may be recycled should total about 300,000 tons (Recyclable ash in t/a: Utilities - 80,000; Pulp and Paper Industry - 100-130,000; Woodworking Industry 100,000). Logging slash is seldom burned alone in the boilers at the utilities, but are almost always mixed with other wood fuel fractions such as waste from sawmills. The mixtures can be very complex. Clean mixtures of wood fuel fractions represent ca 4,500 GWh of the ca 7,800 GWh in this study. Other fuels that are often used in mixtures are peat and Salix, which does not necessarily lead

  12. Modeling and optimization of processes for clean and efficient pulverized coal combustion in utility boilers

    Directory of Open Access Journals (Sweden)

    Belošević Srđan V.

    2016-01-01

    Full Text Available Pulverized coal-fired power plants should provide higher efficiency of energy conversion, flexibility in terms of boiler loads and fuel characteristics and emission reduction of pollutants like nitrogen oxides. Modification of combustion process is a cost-effective technology for NOx control. For optimization of complex processes, such as turbulent reactive flow in coal-fired furnaces, mathematical modeling is regularly used. The NOx emission reduction by combustion modifications in the 350 MWe Kostolac B boiler furnace, tangentially fired by pulverized Serbian lignite, is investigated in the paper. Numerical experiments were done by an in-house developed three-dimensional differential comprehensive combustion code, with fuel- and thermal-NO formation/destruction reactions model. The code was developed to be easily used by engineering staff for process analysis in boiler units. A broad range of operating conditions was examined, such as fuel and preheated air distribution over the burners and tiers, operation mode of the burners, grinding fineness and quality of coal, boiler loads, cold air ingress, recirculation of flue gases, water-walls ash deposition and combined effect of different parameters. The predictions show that the NOx emission reduction of up to 30% can be achieved by a proper combustion organization in the case-study furnace, with the flame position control. Impact of combustion modifications on the boiler operation was evaluated by the boiler thermal calculations suggesting that the facility was to be controlled within narrow limits of operation parameters. Such a complex approach to pollutants control enables evaluating alternative solutions to achieve efficient and low emission operation of utility boiler units. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in

  13. The Swedish Ash Programme 2002-2008. Biomass, wastes, peat - any solid fuel but coal

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem, Henrik; Herbert, Roger

    2009-07-15

    In Sweden, producers of combustion residues have since 2002 implemented a collaborative applied RandD programme aimed at the utilisation of combustion residues (ash). The fuels are biomass, wastes, peat - any solid fuel but coal. In this report, the main lines of the programme are described: Covers for landfills and mine tailings; Civil works, e.g. road-buildings, where both geotechnical and environmental questions have been addressed; Cement and concrete applications; Compensating soils for removing biomass and the mineral nutrients in the biomass. The emphasis of the Programme is on environmental questions, even if technical questions have been treated. The time perspective in this context is much longer than the 3-5 years that are usual in an applied RandD programme, i.e. decades after ash has been placed on a site, e.g. in a road, or spread to forest soil. New test fields have been created in the programme and old test fields have been evaluated in order to gather available information

  14. Standard procedure for the determination of ash-fusion behavior of biomass fuels; Standardisiertes Verfahren zur Bestimmung des thermischen Ascheverhaltens biogener Brennstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Ottmann, M.; Karl, J. [Technische Univ. Muenchen, Garching bei Muenchen (Germany). Lehrstuhl Thermische Kraftanlagen; Hein, D.

    2004-07-01

    An important property of some bio fuels, particularly at combustion in fluidized bed reactors (FBC), is the very low deformation temperature of its ash. Whereas wood ash is melting at very high temperatures (approx. 1400 C to 1500 C) are ashes of grasses or residues of food industry melting at very low temperatures (<900 C). Low sintering and deformation temperatures cause coating and agglomerating of bed particles of the FBC and fouling of heat exchangers. In order to determinate relevant temperature ranges of different fuels these ashes are melted in laboratory experiments. In these experiments fuels will be burned and the ashes will be pressed to defined forms. Subsequently the ash corpus will be heated up. The change of its form will be watched via microscope and recorded. The procedure for the description of the ash-fusion behavior by ash fusion microscope is fixed in DIN 51730 'Determination of the ash fusion behavior'. This standard was developed for fossil solid fuels. With the last expenditure of this DIN in 1998 some new aspects came up regarding the attempt matrix, form of the sample, and also regarding the analysis procedure for the execution of the attempts. Likewise decisions were necessary regarding the type of ashing, the preparation of ash and the pressing power for the samples. A set of experiments was necessary, in order to place a meaningful, reproducible execution. (orig.)

  15. CO2 Rebinding by Oil Shale CFBC Ashes: Effect of Pre-Treatment

    Science.gov (United States)

    Trikkel, Andres; Keelmann, Merli; Aranson, Aljona; Kuusik, Rein

    Power production in Estonia is predominantly based on combustion of a local low-grade fossil fuel Estonian oil shale. Due to the high content of carbonaceous mineral matter in oil shale, its combustion is related to formation of lime-containing ashes (content of free CaO 10-30%) which could be utilized as sorbents for CO2. In the present research CO2 uptake by circulating fluidized bed and pulverized firing ashes from different technological devices (furnace, cyclones etc) of an operating power plant was studied and the effect of pre-treatment (grinding, calcination at different temperatures) of these ashes on their capture capacity was estimated using thermogravimetric, SEM, X-Ray and EDX analysis methods. It was found that capture capacities were determined mainly by free CaO content in the ashes, thereby, fluidized bed ashes showed higher CaO conversion levels (19.2-74.2%) as compared to pulverized firing ones (8.7-51.8%). Pre-treatment conditions influenced noticeably CO2 uptake. Grinding decreased CO2 capture capacity of fluidized bed ashes, calcination at higher temperatures decreased capture capacity of both types of ashes. Clarification of this phenomenon was given. Kinetic analysis of the process has been carried out, mechanism of the reactions and respective kinetic constants have been estimated.

  16. Comparisons of Fly Ash and Deposition Between Air and Oxy-Fuel Combustion in Bench-Scale Fluidized Bed with Limestone Addition

    Institute of Scientific and Technical Information of China (English)

    Zhimin Zheng; Hui Wang∗; Yongjun Guo; Li Yang; Shuai Guo; Shaohua Wu

    2015-01-01

    In Oxy⁃fuel circulating fluidized bed, the residual CaO particles may react with high concentration of CO2 in flue gas to form bonded deposit on heat transfer surfaces in backpass when limestone is used as a sorbent to capture SO2 .In this paper, experiments were designed on ash deposition in a bench⁃scale fluidized bed under oxy⁃fuel and air atmosphere. A novel ash deposit sampling probe was used to simulate the tubes of tail surfaces. The chemical composition of fly ash and ash deposit from both air⁃firing and oxy⁃fuel firing cases were analyzed by Inductively Coupled Plasma⁃Atomic Emission Spectrometry ( ICP⁃AES ) and Scanning Electron Microscopy ( SEM) , respectively. The degrees of carbonation reaction of ash deposits were measured by Thermo Gravimetric Analysis. The results showed that there are distinct differences in fly ash deposition rate between oxy⁃fuel and air firing cases, and oxy⁃fuel combustion with limestone addition can affect chemical composition of fly ash and ash deposit, especially for elements of Ca, Na, K, and S. However, the carbonation reaction degree of ash deposits is found weak, which is due to the relatively low CaO content in ash deposit or not long enough of the sampling time.

  17. Viscosity of ashes from energy production and municipal solid waste handling: A comparative study between two different experimental setups

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming; Folkedahl, B.

    2008-01-01

    This paper discusses the viscosity characteristics of ash fractions produced from the co-combustion of coal and biomass in a pilot-scale pulverized fuel (PF) boiler and from the incineration of municipal solid waste (MSW) in a Danish incinerator that were determined using the high-temperature rot......This paper discusses the viscosity characteristics of ash fractions produced from the co-combustion of coal and biomass in a pilot-scale pulverized fuel (PF) boiler and from the incineration of municipal solid waste (MSW) in a Danish incinerator that were determined using the high......-temperature rotational viscometer method. Two different Setups in the United States and Denmark were purchased by the same company, HAAKE, but different versions of the basic instrument were used in the study to determine the reproducibility of the method. The two sets of measurements show that the method generates...

  18. Mechanical and thermal properties of prepacked aggregate concrete incorporating palm oil fuel ash

    Indian Academy of Sciences (India)

    HOSSEIN MOHAMMADHOSSEINI; A S M ABDUL AWAL; ABDUL RAHMAN MOHD SAM

    2016-10-01

    Prepacked aggregate concrete (PAC) is a special type of concrete which is made by placing coarse aggregate in a formwork and injecting a grout either by pump or under the gravity force to fill the voids. Use of pozzolanic materials in conventional concrete has become increasingly extensive, and this trend is expected to continue in PAC as well. Palm oil fuel ash (POFA) is one of these pozzolanic ash, which has been recognized as a good pozzolanic material. This paper presents the experimental results of the performance behaviour of POFA in developing physical and mechanical properties of prepacked aggregate concrete. Four concrete mixes namely,prepacked concrete with 100% OPC as a control, and PAC with 10, 20 and 30% POFA were cast, and thetemperature growth due to heat of hydration and heat transfer in all the mixtures was recorded. It has been found that POFA significantly reduces the temperature rise in prepacked aggregate concrete and delay the transfer of heat to the concrete body. The compressive and tensile strengths, however, increased with replacement up to20% POFA. The results obtained and the observation made in this study suggest that the replacement of OPC by POFA is beneficial, particularly for prepacked mass concrete where thermal cracking due to extreme heat rise is of great concern.

  19. Influence of palm oil fuel ash on fresh and mechanical properties of self-compacting concrete

    Indian Academy of Sciences (India)

    Hossein Mohammadhosseini; A S M Abdul Awal; Abdul Haq Ehsan

    2015-09-01

    This paper presents experimental results of some fresh and hardened state properties of self-compacting concrete (SCC) incorporating palm oil fuel ash (POFA). Three concrete mixes namely ordinary Portland cement (OPC) concrete i.e. concrete with 100% OPC as control, and concrete with 30% and 60% POFA having different water/binder (w/b) ratios of 0.4, 0.45 and 0.5 were prepared. Filling ability, passing ability and segregation resistance of SCC along with strength properties were determined and compared with those of the OPC based SCC. Test results revealed that replacement of POFA in general decreased the workability of concrete with acceptable range. The compressive strength, however, increased with lower w/b ratio and lower replacement of ash. The splitting tensile and flexural strength values have also followed the same trend. The results obtained and the observation made in this study suggest that POFA can suitably be used as supplementary cementing material in SCC.

  20. Performance of High-Strength Concrete Using Palm Oil Fuel Ash as Partial Cement Replacement

    Directory of Open Access Journals (Sweden)

    Dr. M. Swaroopa Rani

    2015-04-01

    Full Text Available The advancement in material technology has led to development of concrete with higher strengths. Presence of high cementitious materials contents in high strength concrete mixes increases heat of hydration that causes higher shrinkage and leading it to potential of cracking. However, use of supplementary cementitious materials leads to control in heat of hydration which further avoids higher shrinkage. Materials such as fly ash, silica fume, metakaolin and ground granulated blast furnace slag are largely been used as supplementary cementitious materials in High strength concrete mixes. In the present study use of palm oil fuel ash (POFA as partial cement replacement in high strength concrete mixes is evaluated with an experimental study. High strength concrete mix of M60 grade is taken as a reference and the compressive strength, split tensile strength and flexural strength where performed for 7, 28 and 56 days and analyzed it with results for partial replacement mixes of POFA 5%, 10%, 15%, 20% & 25%. It has been observed that concrete with 15% replacement of POFA gave the highest strength.

  1. Utilization of Palm Oil Fuel Ash as Binder in Lightweight Oil Palm Shell Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Michael Yong Jing Liu

    2014-01-01

    Full Text Available Traditionally fly ash (FA has been used to replace cement as binder in the geopolymer concrete. The utilization of palm oil industrial waste materials known as palm oil fuel ash (POFA and oil palm shell (OPS that are abundantly available in South East Asia as binder and coarse aggregate in geopolymer concrete would give an added advantage in both the environmental and economic aspects. The mechanical properties of the OPS geopolymer concrete (OPSGC through the use of POFA, FA, and OPS are investigated and reported. A total of ten OPSGC mixtures were prepared with varying percentages of POFA and FA such as 0, 10, 20, 40, and 100%. The specimens prepared with two alkaline solution to binder (AK/B ratios of 0.35 and 0.55 were oven cured at 65°C for 48 hours. The experimental results showed that the highest compressive strength of 30 MPa was obtained for the mix with 20% replacement of FA by POFA and AK/B ratio of 0.55, which underwent oven curing. Further, the mix of up to 20% POFA (with AK/B ratio of 0.55 can be categorized as structural lightweight concrete. An increase of the POFA content beyond 20% decreases the mechanical properties, and hence this mix is recommended to be used.

  2. Ash fusion temperatures and their association with the transformations of coal ash particles to slag

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.K.; Wall, T.F.; Gupta, R.P. [Cooperative Research Centre for Black Coal Utilisation, Newcastle, NSW (Australia); Creelman, R.A. [Creelman (R.A.) and Associates, Sydney, NSW (Australia)

    1997-04-01

    Ash deposition on furnace walls in PF (pulverized fuel) furnaces is called slagging when it occurs in the high temperature areas of furnaces directly exposed to flame radiation and fouling in other regions such as tubes in the convection section of the boiler. There are well documented shortcomings of certain approaches relating to their uncertainties as predictive tools for plant performance such as poor repeatability and re-producibility of ash fusion measurements. The nature of physical and chemical changes occurring during melting of coal ash has been investigated in the current study to provide an alternative procedure to the ash fusion test. Shrinkage measurements are frequently used in metallurgy and ceramic science to study the physical properties of materials at high temperatures. The output of this experiment provides three to four `peaks` (maximum rate of shrinkage with temperature) of different intensity and at different temperatures which are related to melting characteristics of the sample. It was concluded that shrinkage extents exceeding 50 percent indicated that the effect of the ash particle size is of secondary importance compared to ash chemistry in determining shrinkage levels, with fine particles giving rapid shrinkage events 10 degrees C lower in temperature. (author). 7 figs., refs.

  3. Ash formation, deposition, corrosion, and erosion in conventional boilers

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.A.; Jones, M.L. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-12-01

    The inorganic components (ash-forming species) associated with coals significantly affect boiler design, efficiency of operation, and lifetimes of boiler parts. During combustion in conventional pulverized fuel boilers, the inorganic components are transformed into inorganic gases, liquids, and solids. This partitioning depends upon the association of the inorganic components in the coal and combustion conditions. The inorganic components are associated as mineral grains and as organically associated elements, and these associations of inorganic components in the fuel directly influence their fate upon combustion. Combustion conditions, such as temperature and atmosphere, influence the volatility and the interaction of inorganic components during combustion and gas cooling, which influences the state and size composition distribution of the particulate and condensed ash species. The intermediate species are transported with the bulk gas flow through the combustion systems, during which time the gases and entrained ash are cooled. Deposition, corrosion, and erosion occur when the ash intermediate species are transported to the heat-transfer surface, react with the surface, accumulate, sinter, and develop strength. Research over the past decade has significantly advanced understanding of ash formation, deposition, corrosion, and erosion mechanisms. Many of the advances in understanding and predicting ash-related issues can be attributed to advanced analytical methods to determine the inorganic composition of fuels and the resulting ash materials. These new analytical techniques have been the key to elucidation of the mechanisms of ash formation and deposition. This information has been used to develop algorithms and computer models to predict the effects of ash on combustion system performance.

  4. The influence of particle size, fluidization velocity and fuel type on ash-induced agglomeration in biomass combustion

    Directory of Open Access Journals (Sweden)

    Bernhard eGatternig

    2014-11-01

    Full Text Available Agglomeration of the bed material is one of the main obstacles for biomass utilization in fluidized bed combustors. Especially high-potential fuels such as fast growing energy crops or biogeneous residues are affected, due to their high content of alkaline metals. Despite ongoing research efforts, the knowledge base on what fuels are affected is still limited. This paper describes the design and installation of two lab-scale reactors for the experimental determination of agglomeration temperatures. The reactor concept and measurement method were developed under consideration of experiences from existing test rigs published in literature. Preliminary tests confirmed a reproducibility of ±5°C for both new reactors.The results of an extended measurement campaign (156 test runs of 25 fuel species at a wide range of the operational parameters bed particle size, gas velocity, bed ash accumulation, based on design of experiment criteria, showed high agglomeration tendencies for residues (e.g., dried distillery grains, corn cobs while woody energy crops (e.g., willow, alder exhibited very stable combustion behavior. The operating parameters influenced the agglomeration behavior to a lesser degree than different ash compositions of fuel species tested. An interpolation within the design of experiment factor space allowed for a subsequent comparison of our results with experiments reported in literature. Good agreement was reached for fuels of comparable ash composition considering the interpolation errors of ±32°C on average.

  5. Pulverized coal injection in blast furnaces at ArcelorMittal Tubarao (AMT)

    Energy Technology Data Exchange (ETDEWEB)

    Klein, C.A.; Fujihara, F.K.; Defendi, G.A.; Tauffer Barros, R.J. [ArcelorMittal Tubarao, Serra (Brazil). Ironmaking Dept.

    2008-07-01

    The main factors that influence the performance of coal injected into blast furnaces include coal properties, combustion conditions and the equipment used in the plants for grinding, transportation and injection of coal. This paper focused on coal properties and the main operational control changes in the no.1 blast furnace at ArcelorMittal Tubarao. The furnace was modified from an all coke operation to a pulverized coal injection (pci) operation in order to ensure high productivity, low fuel consumption and longer service life. ArcelorMittal Tubarao has developed a coal buying model based on energy balance and the chemical analysis of ash. In the energy balance, the ratio between the heat supplied by carbon combustion and the heat consumed by the cracking of water and volatiles results in the potential rate of coke replacement by coal. 5 refs., 1 tab., 10 figs.

  6. Insulating brick from fly ash of thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S.N.; Majumdar, A.; Majumdar, S.K.

    1986-04-01

    Disposal of fly ash, a major byproduct of thermal power stations burning high ash pulverized fuel, has posed a serious problem of storage space required on one hand and the cost involved on the other. Fly ash possesses pozzolanic property. R and D work on utilization of fly ash in the form of sand-lime brick or cellular concrete has been already done. Other avenues of utilization are cement and concrete industry. All these are based on pozzolanic property of fly ash which decreases with the increase of unburnt carbon content in the same. The overall present consumption of fly ash is barely 5-7 per cent of the total production. A process has been developed to utilize fly ash with comparatively higher amount of carbonaceous matter in particular, to make insulating/semi-insulating bricks of standard size through use of other normal ingredients like clay (a plastic material), sulphite lye, molasses, etc. as binder along with some propertion of saw dust. The bricks made so far have been tested for their normal properties and these conform to a product of semi-insulating type. 21 refs., 2 tabs.

  7. Feasibility of Pulverized Oyster Shell as a Cementing Material

    Directory of Open Access Journals (Sweden)

    Chou-Fu Liang

    2013-01-01

    Full Text Available This research intends to study the cementing potential of pulverized oyster shell, rich in calcium, when mixed with fly ash and soil. Cylindrical compacted soil and cubic lime specimens with different proportions of the shells and fly ash are made to study the strength variance. Soil, which is classified as CL in the USCS system, commercialized pulverized oyster shell, F-type fly ash, and lime are mixed in different weight percentages. Five sample groups are made to study the compressive strength of soil and lime specimens, respectively. The lime cubes are made with 0.45 W/B ratio and the cylindrical soils are compacted under the standard Procter compaction process with 20% moisture content. The results show that increment of shell quantity result to lower strength on both the soil and lime specimens. In a 56-day curing, the compressive strength of the lime cubes containing fly ash increases evidently while those carrying the shell get little progress in strength. The soil specimens containing fly ash gradually gain strength as curing proceeds. It suggests that mixtures of the shell and fly ash do not process any Pozzolanic reaction nor help to raise the unconfined strength of the compacted soil through the curing.

  8. Micro Fine Sized Palm Oil Fuel Ash Produced Using a Wind Tunnel Production System

    Directory of Open Access Journals (Sweden)

    R. Ahmadi

    2016-01-01

    Full Text Available Micro fine sized palm oil fuel ash (POFA is a new supplementary cementitious material that can increase the strength, durability, and workability of concrete. However, production of this material incurs high cost and is not practical for the construction industry. This paper investigates a simple methodology of producing micro fine sized POFA by means of a laboratory scale wind tunnel system. The raw POFA obtained from an oil palm factory is first calcined to remove carbon residue and then grinded in Los Angeles abrasion machine. The grinded POFA is then blown in the fabricated wind tunnel system for separation into different ranges of particle sizes. The physical, morphological, and chemical properties of the micro fine sized POFA were then investigated using Laser Particle Size Analyser (PSA, nitrogen sorption, and Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX. A total of 32.1% micro fine sized POFA were collected from each sample blown, with the size range of 1–10 micrometers. The devised laboratory scale of wind tunnel production system is successful in producing micro fine sized POFA and, with modifications, this system is envisaged applicable to be used to commercialize micro fine sized POFA production for the construction industry.

  9. Coral recruitment onto an experimental pulverised fuel ash-concrete artificial reef.

    Science.gov (United States)

    Lam, Katherine K Y

    2003-05-01

    An experimental artificial reef was deployed in December 1993 at Hoi Ha Wan Marine Park, Hong Kong. This is the first study documenting natural scleractinian coral recruitment onto a stabilised pulverised fuel ash (PFA)-concrete artificial reef. Visible recruits were first recorded 9-10 months after the placement of reef blocks, i.e., in the autumn of 1994. Two scleractinians, Oulastrea crispata and Culicia japonica, were recruited. The recruit density of the former was much greater than the latter. The spatial recruitment pattern of the corals was observed to be affected by the orientation of the attaching surface. O. crispata settled predominantly on the undersides of the reef blocks. There was an edge effect on O. crispata recruitment. C. japonica, however, had a preference for exposed surfaces. O. crispata did not show a preference for block composition whereas C. japonica favoured blocks with high (75% by volume) PFA levels. This shows that PFA-concrete is a potential substratum for artificial reef construction, especially when such reefs aim at rehabilitating corals.

  10. Intra- and inter-unit variation in fly ash petrography and mercury adsorption: Examples from a western Kentucky power station

    Science.gov (United States)

    Hower, J.C.; Finkelman, R.B.; Rathbone, R.F.; Goodman, J.

    2000-01-01

    Fly ash was collected from eight mechanical and 10 baghouse hoppers at each of the twin 150-MW wall-fired units in a western Kentucky power station. The fuel burned at that time was a blend of many low-sulfur, high-volatile bituminous Central Appalachian coals. The baghouse ash showed less variation between units than the mechanical hoppers. The mechanical fly ash, coarser than the baghouse ash, showed significant differences in the amount of total carbon and in the ratio of isotropic coke to both total carbon and total coke - the latter excluding inertinite and other unburned, uncoked coal. There was no significant variation in proportions of inorganic fly ash constituents. The inter-unit differences in the amount and forms of mechanical fly ash carbon appear to be related to differences in pulverizer efficiency, leading to greater amounts of coarse coal, therefore unburned carbon, in one of the units. Mercury capture is a function of both the total carbon content and the gas temperature at the point of fly ash separation, mercury content increasing with an increase in carbon for a specific collection system. Mercury adsorption on fly ash carbon increases at lower flue-gas temperatures. Baghouse fly ash, collected at a lower temperature than the higher-carbon mechanically separated fly ash, contains a significantly greater amount of Hg.

  11. Enhanced Combustion Low NOx Pulverized Coal Burner

    Energy Technology Data Exchange (ETDEWEB)

    David Towle; Richard Donais; Todd Hellewell; Robert Lewis; Robert Schrecengost

    2007-06-30

    economic evaluation and commercial application. During the project performance period, Alstom performed computational fluid dynamics (CFD) modeling and large pilot scale combustion testing in its Industrial Scale Burner Facility (ISBF) at its U.S. Power Plant Laboratories facility in Windsor, Connecticut in support of these objectives. The NOx reduction approach was to optimize near-field combustion to ensure that minimum NOx emissions are achieved with minimal impact on unburned carbon in ash, slagging and fouling, corrosion, and flame stability/turn-down. Several iterations of CFD and combustion testing on a Midwest coal led to an optimized design, which was extensively combustion tested on a range of coals. The data from these tests were then used to validate system costs and benefits versus SCR. Three coals were evaluated during the bench-scale and large pilot-scale testing tasks. The three coals ranged from a very reactive subbituminous coal to a moderately reactive Western bituminous coal to a much less reactive Midwest bituminous coal. Bench-scale testing was comprised of standard ASTM properties evaluation, plus more detailed characterization of fuel properties through drop tube furnace testing and thermogravimetric analysis. Bench-scale characterization of the three test coals showed that both NOx emissions and combustion performance are a strong function of coal properties. The more reactive coals evolved more of their fuel bound nitrogen in the substoichiometric main burner zone than less reactive coal, resulting in the potential for lower NOx emissions. From a combustion point of view, the more reactive coals also showed lower carbon in ash and CO values than the less reactive coal at any given main burner zone stoichiometry. According to bench-scale results, the subbituminous coal was found to be the most amenable to both low NOx, and acceptably low combustibles in the flue gas, in an air staged low NOx system. The Midwest bituminous coal, by contrast, was

  12. Ash chemistry and fuel design focusing on combustion of phosphorus-rich biomass

    OpenAIRE

    Skoglund, Nils

    2014-01-01

    Biomass is increasingly used as a feedstock in global energy production. This may present operational challenges in energy conversion processes which are related to the inorganic content of these biomasses. As a larger variety of biomass is used the need for a basic understanding of ash transformation reactions becomes increasingly important. This is not only to reduce operational problems but also to facilitate the use of ash as a nutrient source for new biomass production. Ash transformatio...

  13. Utilization of Swedish fly ash from bio fuel fired power plants as a filler material in concrete; Anvaendning av svenska flygaskor som fillermaterial i betong

    Energy Technology Data Exchange (ETDEWEB)

    Sundblom, Hillevi [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

    2006-03-15

    The tested Swedish fly ashes (FA) (FA from bio combustion) in this project proved to have good filler qualities such as improving the stability and the rheological behavior of the concrete. One of tested FA could directly replace the compared limestone filler in the concrete recipes in booth laboratory investigation and in full-scale demonstration. The other FA demanded more water. The recipes were modified in the laboratory investigation to get a functional recipe for full-scale demonstration. The process to investigate the Swedish FA has been following (this project is one part of several investigation): Basic characterization; Characterization as a filler material; Full-scale demonstration; Certification, regularly quality assurance; Continuous use of Swedish FA in the Swedish Concrete Industry. Three representatives Swedish FA have been investigated in step 1-3 according to the process above. There were two FA in a full-scale demonstration a FA from bio fuel/paper sludge fired circulated fluidized bed boiler (at a paper mill) and a FA from a peat fired pulverized boiler. The test made was basic chemical and physical characterization, investigation as a filler material and strength development of a crushed aggregate self-compacting concrete in laboratory and in a full-scale demonstration. The conclusion were following: FA from the paper mill CFB boiler changes in strength development depending on the combustion temperature. It seems the reason is in the way CaO is distribute into different chemical compounds. Higher compressive strength with higher free CaO (analyzed in XRD) Higher content of reactive SiO{sub 2} and free lime in the CFB FA comparing with the PF FA. The soundness of the FA have been tested in early research projects. The sieves curves demonstrated that the FA from the CFB boiler coarser than the other FA tested and the limestone filler compared. The coarser grain fraction could explain why the FA demanded more water in the laboratory and full

  14. The Effect of Variation of Molarity of Alkali Activator and Fine Aggregate Content on the Compressive Strength of the Fly Ash: Palm Oil Fuel Ash Based Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    Iftekhair Ibnul Bashar

    2014-01-01

    Full Text Available The effect of molarity of alkali activator, manufactured sand (M-sand, and quarry dust (QD on the compressive strength of palm oil fuel ash (POFA and fly ash (FA based geopolymer mortar was investigated and reported. The variable investigated includes the quantities of replacement levels of M-sand, QD, and conventional mining sand (N-sand in two concentrated alkaline solutions; the contents of alkaline solution, water, POFA/FA ratio, and curing condition remained constant. The results show that an average of 76% of the 28-day compressive strength was found at the age of 3 days. The rate of strength development from 3 to 7 days was found between 12 and 16% and it was found much less beyond this period. The addition of 100% M-sand and QD shows insignificant strength reduction compared to mixtures with 100% N-sand. The particle angularity and texture of fine aggregates played a significant role in the strength development due to the filling and packing ability. The rough texture and surface of QD enables stronger bond between the paste and the fine aggregate. The concentration of alkaline solution increased the reaction rate and thus enhanced the development of early age strength. The use of M-sand and QD in the development of geopolymer concrete is recommended as the strength variation between these waste materials and conventional sand is not high.

  15. Coal char fragmentation during pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L.

    1995-07-01

    A series of investigations of coal and char fragmentation during pulverized coal combustion is reported for a suite of coals ranging in rank from lignite to low-volatile (lv) bituminous coal under combustion conditions similar to those found in commercial-scale boilers. Experimental measurements are described that utilize identical particle sizing characteristics to determine initial and final size distributions. Mechanistic interpretation of the data suggest that coal fragmentation is an insignificant event and that char fragmentation is controlled by char structure. Chars forming cenospheres fragment more extensively than solid chars. Among the chars that fragment, large particles produce more fine material than small particles. In all cases, coal and char fragmentation are seen to be sufficiently minor as to be relatively insignificant factors influencing fly ash size distribution, particle loading, and char burnout.

  16. Making the most of South Africa’s low-quality coal: Converting high-ash coal to fuel gas using bubbling fluidised bed gasifiers

    CSIR Research Space (South Africa)

    Engelbrecht, AD

    2010-08-31

    Full Text Available South Africa has abundant resources of high-ash and other low-quality coals. The aim of this work is to investigate the possibility of using fluidised bed gasification technology to convert these coals into clean fuel gas. The fuel gas can be used...

  17. Ash chemistry and behavior in advanced co-combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Skrifvars, B.J. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    The purpose of this LIEKKI 2 project is to report results achieved within the EU/JOULE/OPTEB project to the Finnish combustion research community through the LIEKKI program. The purpose of the EU/JOULE/OPTEB project is to find prediction methods for evaluating ash behavior, such as slagging, fouling and corrosion propensity, in full scale combustion systems through chemical or mineralogical analyses, intelligent laboratory tests and chemistry calculations. The project focuses on coals, coal mixtures and coal biomass mixtures fired in advanced combustion systems, such as fluidized bed boilers, pulverized fuel boilers with critical steam values etc. The project will make use of (1) advanced multi-component combustion equilibrium calculations, (2) ash sintering tendency laboratory tests and (3) chemical evaluations of slagging, fouling and corrosion measurements in full scale units. (orig.)

  18. Fabrication of bricks from paper sludge and palm oil fuel ash

    Directory of Open Access Journals (Sweden)

    Mohammad Ismail

    2010-05-01

    Full Text Available Increasing amount of disposed paper sludge and palm oil fuel ash (POFA from industries has recently attracted concern for an alternative environmentally sustainable application. This paper presents results of laboratory work carried out on these by-products in order to evaluate application performance. Brick specimens made with various proportions of cement, paper sludge and POFA were fabricated and studied under laboratory conditions. Curing periods of 7, 28 and 84 days were applied followed by compressive strength test. Leaching and water absorption capacities were also assessed as prime steps towards monitoring durability in service. It was found that paper sludge-POFA brick made with 60% cement, 20% sludge and 20% POFA satisfies the strength requirements of BS 6073 Part 2: 2008 and that the amount of copper as well as lead resulting from leaching are within the acceptable limits of ‘Malaysia Environmental Waste Disposal Act’

  19. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature.

    Science.gov (United States)

    Saqib, Naeem; Bäckström, Mattias

    2014-12-01

    Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. 磨细固硫灰渣作为混合材对水泥性能的影响%Performance of Cement Blending Pulverized Ash and Slag from Fluidized Bed Combustion

    Institute of Scientific and Technical Information of China (English)

    牛茂威; 谢小莉; 林洲; 张克; 钱觉时

    2013-01-01

    Fluidized bed combustion (FBC) ash and slag with higher anhydrite and f-CaO may cause poor volume stability used as cement mixing materials. By controlling the dosage of the FBC ash and slag, grinding them to different fineness, the standard consistency requirement, linear expansion rate and mortar strength of the cement blended FBC ash and slag were tested, and compared with the ordinary Portland cement. Results show that increasing the fineness of FBC ash and slag, especially for the ash, could reduce the standard consistency requirement of the cement and delay the setting time. Variation in fineness of FBC ash and slag has no significant influence on the shrinkage in air curing, and higher fineness would accelerate the early expansion in moisture curing, which is within a safe range. The increase of the fineness of FBC ash and slag promotes remarkably the strength of the cement. It is suggested that milling is beneficial to utilization of the FBC ash and slag in cement.%  流化床固硫灰渣含有较高无水石膏和f-CaO,作为水泥混合材利用时会存在体积稳定性问题。在控制固硫灰渣掺量前提下,将固硫灰渣粉磨至不同细度,测试了掺加固硫灰渣的水泥标准稠度需水量、线性膨胀率和胶砂强度,并与普通硅酸盐水泥进行对比。结果表明,提高固硫灰渣细度,特别是固硫灰细度,能使水泥标准稠度需水量减少;固硫灰渣细度提高,水泥凝结时间有所延长;自然养护条件下,固硫灰渣细度变化对水泥收缩没有明显影响,潮湿养护下,磨细固硫灰渣早期能够释放较多膨胀,但处于可控范围;固硫灰渣细度增加,水泥强度明显提高。磨细有利于固硫灰渣作为水泥混合材利用。

  1. Enhancement of pulverized coal combustion by plasma technology

    Energy Technology Data Exchange (ETDEWEB)

    Gorokhovski, M.A.; Jankoski, Z.; Lockwood, F.C.; Karpenko, E.I.; Messerle, V.E.; Ustimenko, A.B. [University of Rouen, Rouen (France)

    2007-07-01

    Plasma-assisted pulverized coal combustion is a promising technology for thermal power plants (TPP). This article reports one- and three- dimensional numerical simulations, as well as laboratory and industrial measurements of coal combustion using a plasma-fuel system (PFS). The chemical kinetic and fluid mechanics involved in this technology are analysed. The results show that a PFS, can be used to promote early ignition and enhanced stabilization of a pulverized coal flame. It is shown that this technology, in addition to enhancing the combustion efficiency of the flame, reduces harmful emissions from power coals of all ranks (brown, bituminous, anthracite and their mixtures). Data summarising the experience of 27 pulverized coal boilers in 16 thermal power plants in several countries (Russia, Kazakhstan, Korea, Ukraine, Slovakia, Mongolia and China), embracing steam productivities from 75 to 670 tons per hour (TPH), are presented. Finally, the practical computation of the characteristics of the PFS, as function of coal properties, is discussed.

  2. Observer-Based Fuel Control Using Oxygen Measurement. A study based on a first-principles model of a pulverized coal fired Benson Boiler

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Palle; Bendtsen, Jan Dimon; Mortensen, Jan Henrik; Just Nielsen, Rene; Soendergaard Pedersen, Tom [Aalborg Univ. (Denmark). Dept. of Control Engineering

    2005-01-01

    This report describes an attempt to improve the existing control of coal mills used at the Danish power plant Nordjyllandsvaerket Unit 3. The coal mills pulverize raw coal to a fine-grained powder, which is injected into the furnace of the power plant. In the furnace the coal is combusted, producing heat, which is used for steam production. With better control of the coal mills, the power plant can be controlled more efficiently during load changes, thus improving the overall availability and efficiency of the plant. One of the main difficulties from a control point of view is that the coal mills are not equipped with sensors that detect how much coal is injected into the furnace. During the project, a fairly detailed, non-linear differential equation model of the furnace and the steam circuit was constructed and validated against data obtained at the plant. It was observed that this model was able to capture most of the important dynamics found in the data. Based on this model, it is possible to extract linearized models in various operating points. The report discusses this approach and illustrates how the model can be linearized and reduced to a lower-order linear model that is valid in the vicinity of an operating point by removing states that have little influence on the overall response. A viable adaptive control strategy would then be to design controllers for each of these simplified linear models, i.e., the control loop that sets references to the coal mills and feedwater, and use the load as a separate input to the control. The control gains should then be scheduled according to the load. However, the variations and uncertainties in the coal mill are not addressed directly in this approach. Another control approach was taken in this project, where a Kalman filter based on measurements of air flow blown into the furnace and the oxygen concentration in the flue gas is designed to estimate the actual coal flow injected into the furnace. With this estimate

  3. Influence of wheat kernel physical properties on the pulverizing process.

    Science.gov (United States)

    Dziki, Dariusz; Cacak-Pietrzak, Grażyna; Miś, Antoni; Jończyk, Krzysztof; Gawlik-Dziki, Urszula

    2014-10-01

    The physical properties of wheat kernel were determined and related to pulverizing performance by correlation analysis. Nineteen samples of wheat cultivars about similar level of protein content (11.2-12.8 % w.b.) and obtained from organic farming system were used for analysis. The kernel (moisture content 10 % w.b.) was pulverized by using the laboratory hammer mill equipped with round holes 1.0 mm screen. The specific grinding energy ranged from 120 kJkg(-1) to 159 kJkg(-1). On the basis of data obtained many of significant correlations (p kernel physical properties and pulverizing process of wheat kernel, especially wheat kernel hardness index (obtained on the basis of Single Kernel Characterization System) and vitreousness significantly and positively correlated with the grinding energy indices and the mass fraction of coarse particles (> 0.5 mm). Among the kernel mechanical properties determined on the basis of uniaxial compression test only the rapture force was correlated with the impact grinding results. The results showed also positive and significant relationships between kernel ash content and grinding energy requirements. On the basis of wheat physical properties the multiple linear regression was proposed for predicting the average particle size of pulverized kernel.

  4. Insulating capacity of fly ash pastes used for passive protection against fire

    Energy Technology Data Exchange (ETDEWEB)

    Luis F. Vilches; Carlos Leiva; Jose Vale; Constantino Fernandez-Pereira [Universidad de Sevilla, Seville (Spain). Escuela Superior de Ingenieros, Departamento de Ingenieria Quimica y Ambiental

    2005-09-01

    This study deals with the possibilities of recycling different combustion sub-products into usable products for passive protection against fire. We studied conventional combustion fly ashes from different types of pulverized coal in thermal power plants, which have a long tradition of applicability in construction, and ashes from new energy production processes based on other fuels, such as biomass, in an effort to find new applications for them. In order to be able to carry out this study, we developed a methodology that allows us to (1) predict the insulating behaviour of pastes comprising ashes, binders and other additives, (2) know what contributions each of the components makes and (3) considerably reduce the time required to test potential products with fire-resistant properties.

  5. Fundamental study of ash formation and deposition: Effect of reducing stoichiometry. Quarterly report No. 2, 1 July 1993--30 September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J.; Srinivasachar, S.: Wilemski, G.; Kang, S.G. [PSI Technology Co., Andover, MA (United States); Sarofim, A.F. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Peterson, T.W.; Bool, L.E. [Arizona Univ., Tucson, AZ (United States); Huffman, G.P.; Huggins, F.E.; Shah, N. [Kentucky Univ., Lexington, KY (United States)

    1993-11-01

    The technical objectives of this project are: To identify the partitioning of inorganic coal constituents among vapor, submicron fume, and fly ash products generated during the combustion of pulverized coal under a variety of combustion conditions. Fuel lean and fuel rich combustion conditions will be considered. To identify and quantify the fundamental processes by which the transformations of minerals and organically-associated inorganic species occur. Emphasis will be placed on identifying any changes that occur as a result of combustion under sub-stoichiometric combustion conditions. To incorporate the effects of combustion stoichiometry into an Engineering Model for Ash Formation based upon the understanding developed in (a) and (b). When completed, this model wig predict the particle size and chemical composition distributions of ash formed during the combustion of pulverized coal under a broad range of conditions. The work discussed in this report highlights the accomplishments of the second quarter of this two year project. This includes the final selection of coals by PSI PowerServe, the results of initial in-situ XAFS combustion measurements by the University of Kentucky, a review of the status of ash formation and deposition models by MIT, modeling of iron behavior during coal combustion by the University of Arizona, preliminary work on the redistribution of minerals within char during the early stages of combustion by PSI PowerServe, and the incorporation of a char fragmentation mechanism into the ash formation model by PSI PowerServe.

  6. Ash chemistry aspects of straw and coal-straw co-firing in utility boilers

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, F.; Nielsen, H.P.; Hansen, L.A.; Hansen, P.F.B.; Andersen, K.H.; Soerensen, H.S.

    1998-12-01

    Deposits formed in straw-fired grate-boilers showed significant amounts of KCl ( 40 - 80 % (w/w)) and KCl-coated Ca-Si-rich particles. CFB co-firing of straw and coal caused deposits in the convective pass containing predominantly K{sub 2}SO{sub 4} (50 - 60 % (w/w)) with small amounts of KCl close to the metal surface. In pulverized coal-straw co-fired boilers, deposits almost free of KCl were found. Most of the potassium in these deposits is derived from K-Al-Si-rich fly ash particles and the rest occurs as K{sub 2}SO{sub 4}. The presence of K-Al-Si-rich fly ash particles indicates that solid residue quality and reuse of fly ash in cement and concrete production rather than deposit formation may be of concern when utilizing straw in pulverized fuel boilers. This paper provides a review of Danish experiences with high-temperature ash deposit formation in the following full-scale utility boilers: Slagelse CHP (31 MW{sub th}), Haslev CHP (23 MW{sub th}) and Rudkoebing CHP (10.7 MW{sub th}), all straw-fired grate-boilers; Grenaa CHP (80 MW{sub th}), a coal-straw co-fired Circulating Fluidized Bed (CFB) boiler; and the Midtkraft-Studstrup Power Station, Unit l (380 MW{sub th}), a coal-straw co-fired pf-boiler. (au)

  7. Two-in-one fuel combining sugar cane with low rank coal and its CO₂ reduction effects in pulverized-coal power plants.

    Science.gov (United States)

    Lee, Dong-Wook; Bae, Jong-Soo; Lee, Young-Joo; Park, Se-Joon; Hong, Jai-Chang; Lee, Byoung-Hwa; Jeon, Chung-Hwan; Choi, Young-Chan

    2013-02-05

    Coal-fired power plants are facing to two major independent problems, namely, the burden to reduce CO(2) emission to comply with renewable portfolio standard (RPS) and cap-and-trade system, and the need to use low-rank coal due to the instability of high-rank coal supply. To address such unresolved issues, integrated gasification combined cycle (IGCC) with carbon capture and storage (CCS) has been suggested, and low rank coal has been upgraded by high-pressure and high-temperature processes. However, IGCC incurs huge construction costs, and the coal upgrading processes require fossil-fuel-derived additives and harsh operation condition. Here, we first show a hybrid coal that can solve these two problems simultaneously while using existing power plants. Hybrid coal is defined as a two-in-one fuel combining low rank coal with a sugar cane-derived bioliquid, such as molasses and sugar cane juice, by bioliquid diffusion into coal intrapores and precarbonization of the bioliquid. Unlike the simple blend of biomass and coal showing dual combustion behavior, hybrid coal provided a single coal combustion pattern. If hybrid coal (biomass/coal ratio = 28 wt %) is used as a fuel for 500 MW power generation, the net CO(2) emission is 21.2-33.1% and 12.5-25.7% lower than those for low rank coal and designed coal, and the required coal supply can be reduced by 33% compared with low rank coal. Considering high oil prices and time required before a stable renewable energy supply can be established, hybrid coal could be recognized as an innovative low-carbon-emission energy technology that can bridge the gulf between fossil fuels and renewable energy, because various water-soluble biomass could be used as an additive for hybrid coal through proper modification of preparation conditions.

  8. The characterisation of carbonaceous fly-ash particles from major European fossil-fuel types and applications to environmental samples

    Science.gov (United States)

    Rose, N. L.; Juggins, S.; Watt, J.

    This paper describes the development of a technique to characterise carbonaceous fly-ash particles produced from five major European fuel-types (coal, oil, brown coal, peat and oil shale) using individual particle chemistries derived from energy dispersive spectroscopy as part of the EU COPERNICUS funded FLAME project. The final classification employed an hierarchy of quadratic discriminant functions such that 80% of the particles could be allocated to the correct fuel-type. The technique was then applied to particles extracted from the surface sediments of 196 lakes across four countries (UK, Estonia, Czech Republic and Ireland) so that the spatial distribution of impacts from these fuel sources could be determined. Spatial trends in fuel-type showed good agreement with known emission sources but absolute percentages were low in all countries due to high allocations to the "coal" fuel-type. It is thought that these high coal values are due to mineral particles surviving the acid pre-treatment. However, the results can still be used to determine sources of pollutant deposition. The technique is applicable to particles extracted from any depositional sink including, atmospheric collectors, building stone crusts, leaves and soils.

  9. Assessment of ecotoxicological risks of element leaching from pulvarized coal ashes.

    OpenAIRE

    1995-01-01

    This thesis describes the consequences of the disposal of the combustion residues of coal, especially the uptake of elements from such residues and their effects on various organisms. The effects on benthic organisms in fresh and in seawater are considered in the first two parts. The third part looks at the uptake of elements from coal residues and their effect on the growth of plants and worms.The central theme is the combustion residue known as pulverized fuel ash (PFA), or 'flyash'. Coal i...

  10. Characterisation of ashes produced by co-combustion of recovered fuels and peat

    Energy Technology Data Exchange (ETDEWEB)

    Frankenhaeuser, M.; Zevenhoven, R. [Borealis Polymers Oy, Porvoo (Finland); Skrifvars, B.J. [Aabo Akademi, Turku (Finland); Orjala, M. [VTT Energy, Espoo (Finland); Peltola, K. [Foster Wheeler Energy (Finland)

    1996-12-01

    Source separation of combustible materials from household or municipal solid waste yields a raw material for the production of Packaging Derived Fuel (PDF). This fuel can substitute the traditional fuels in heat and power generation and is also called recycled fuel. Co-combustion of these types of fuels with coal has been studied in several LIEKKI-projects and the results have been both technically and environmentally favourable. (author)

  11. Effects of kaolin-additions in combustion of wood fuels on hardening and leaching properties of ash; Paaverkan av kaolintillsats vid foerbraenning av biobraensle paa askans haerdnings- och lakningsegenskaper

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Karlfeldt, Karin (Dept. of Chemical And Biological Engineering, Chalmers Univ. of Technology, SE-412 96 Goeteborg (Sweden)). e-mail: bms@chalmers.se

    2007-06-15

    In several investigations it has been shown that kaolin works well as an anti-agglomerating and anti-ash sintering agent in combustion of bio-fuels with a potassium rich ash in fluidised bed boilers. Combustion tests have shown that the kaolin addition may result in an ash melting temperature that is a couple of hundred degrees centigrade higher than for the original ash. This way the kaolin hinders the fouling of super heater surfaces by sticky ash. Many boiler owners treat their wood fuel ash with the aim to recycle it to forest soil as a nutrient source and acid neutralising agent. Therefore it was considered important to investigate if an addition of kaolin in the boiler would have a negative influence on the ash leaching properties. Thus, the aim of the project was to investigate the hardening reactions and leaching properties of normal wood ash and wood ash produced with addition of kaolin. The ash samples were produced in the same boiler and in similar combustion conditions. It was especially interesting to study if the ash would contain soluble aluminium due to the kaolin addition since aluminium in solution may have negative effects on the eco system. The results showed that an important difference between the normal fly ash and the fly ash with kaolin was that the release of potassium i leaching was decreased due to the kaolin addition, especially at high pH levels. This is positive, since potassium normally is released very fast in the forest. In addition, the kaolin containing ash has a faster initial setting/hardening process than the normal ash. The structure of the hardened ash particles is also more durable than that of the normal ash. This is also a positive effect since it indicates that it could be possible to handle the hardened ash after a shorter storage period. However, it has not been investigated if this effect remains in large scale operation and in a longer time perspective. The acid neutralising capacity of fly ash with kaolin is

  12. Exploratory Study of Palm Oil Fuel Ash as Partial Cement Replacement in Oil Palm Shell Lightweight Aggregate Concrete

    Directory of Open Access Journals (Sweden)

    K. Muthusamy

    2014-07-01

    Full Text Available In Malaysia, issue of environmental pollution resulting from disposal of Palm Oil Fuel Ash (POFA which is a by-product from palm oil mill has initiated research to incorporate this waste in Oil Palm Shell (OPS lightweight aggregate concrete production. The current study investigates the effect of palm oil fuel ash content as partial cement replacement towards compressive strength OPS lightweight aggregate concrete. Several OPS lightweight aggregate concrete mixes were produced by replacing various percentage of POFA ranging from 10, 20, 30, 40 and 50%, respectively by weight of cement. All the mixes were cast in form of cubes and then subjected to water curing until the testing date. The compressive strength test is conducted in accordance to BSEN 12390 (2009 at 7 and 28 days. From the results, it was observed that the combination of appropriate POFA content would enhance the compressive strength of OPS lightweight aggregate concrete. Specimen produced using 20% POFA as partial cement replacement exhibit higher value of compressive strength than that of control OPS lightweight aggregate concrete. However, mixes consisting POFA up to 50% is also suitable for structural application.

  13. Taguchi design and flower pollination algorithm application to optimize the shrinkage of triaxial porcelain containing palm oil fuel ash

    Science.gov (United States)

    Zainudin, A.; Sia, C. K.; Ong, P.; Narong, O. L. C.; Nor, N. H. M.

    2017-01-01

    In the preparation of triaxial porcelain from Palm Oil Fuel Ash (POFA), a new parameter variable must be determined. The parameters involved are the particle size of POFA, percentage of POFA in triaxial porcelain composition, moulding pressure, sintering temperature and soaking time. Meanwhile, the shrinkage is the dependent variable. The optimization process was investigated using a hybrid Taguchi design and flower pollination algorithm (FPA). The interaction model of shrinkage was derived from regression analysis and found that the shrinkage is highly dependent on the sintering temperature followed by POFA composition, moulding pressure, POFA particle size and soaking time. The interaction between sintering temperature and soaking time highly affects the shrinkage. From the FPA process, targeted shrinkage approaching zero values were predicted for 142 μm particle sizes of POFA, 22.5 wt% of POFA, 3.4 tonne moulding pressure, 948.5 °C sintering temperature and 264 minutes soaking time.

  14. Dewatering of ashes from mixed fuels. Experiences and results from Tekniska Verken in Linkoeping; Avvattning av aska fraan blandbraenslen. Erfarenheter och resultat fraan Tekniska Verken i Linkoeping

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Ulf; Fredriksson, Anders; Lindahl, Inge [Tekniska Verken i Linkoeping AB (Sweden); Arevius, Anna; Sjoeblom, Rolf [AaF-Energikonsult AB, Stockholm (Sweden)

    2003-12-01

    Unit 3 at Tekniska Verken i Linkoeping (TVL) has a grid type furnace. During the firing season 2000 - 2001, the fuel has been comprising 45 % recovered wood chip, 45 % bark and 10 % recovered plastic material. The outfeed has been wet, and flyash and bottom ash have been mixed in the process. During 1999, about 19,000 tonnes of ash with a water content of about 50 % have been generated. The procedure has implied drawbacks in the form of handling of sludge and disposal of material with a high water content. The purpose of the work carried out has been to provide a basis for design of a handling in which these drawbacks have been eliminated, and which supports other destinations for the bottom ash than disposal. The search for information showed that a number of reactions, in particular hydratisation and recrystallisation, take place when ash is in contact with water. The process is strongly dependent on the chemical composition of the ash. The result is influenced not only by the chemical reactions that occur but also by the order in which they take place. Fly ash is very reactive while bottom ash is relatively inert. The experiments in the laboratory scale showed that bottom ash drained well while fly ash as well as different mixtures of fly ash and bottom ash are relatively impermeable to water. The ageing experiments which were carried out did not indicate any particular alteration in the permeability. Tests on a reduced scale clearly showed that bottom ash drains rapidly without the aid of vacuum and that the field capacity (the relative amount of water which does not drain) is low. Mixtures of bottom ash and fly ash drained more when vacuum was applied. However, such mixtures cured within a few hours and this lead to a substantial decrease in permeability. Tests on a pilot scale were conducted using three different methods of dewatering. The tests on self-percolation showed that most of the drainage water appeared during the first few hours where after the

  15. A scanning electron microscopy study of ash, char, deposits and fuels from straw combustion and co-combustion of coal and straw

    Energy Technology Data Exchange (ETDEWEB)

    Sund Soerensen, H.

    1998-07-01

    The SEM-study of samples from straw combustion and co-combustion of straw and coal have yielded a reference selection of representative images that will be useful for future comparison. The sample material encompassed potential fuels (wheat straw and grain), bottom ash, fly ash and deposits from straw combustion as well as fuels (coal and wheat straw), chars, bottom ash, fly ash and deposits from straw + coal co-combustion. Additionally, a variety of laboratory ashes were studied. SEM and CCSEM analysis of the samples have given a broad view of the inorganic components of straw and of the distribution of elements between individual ash particles and deposits. The CCSEM technique does, however, not detect dispersed inorganic elements in biomass, so to get a more complete visualization of the distribution of inorganic elements additional analyses must be performed, for example progressive leaching. In contrast, the CCSEM technique is efficient in characterizing the distribution of elements in ash particles and between ash fractions and deposits. The data for bottom ashes and fly ashes have indicated that binding of potassium to silicates occurs to a significant extent. The silicates can either be in the form of alumino-silicates or quartz (in co-combustion) or be present as straw-derived amorphous silica (in straw combustion). This process is important for two reasons. One is that potasium lowers the melting point of silica in the fly ash, potentially leading to troublesome deposits by particle impaction and sticking to heat transfer surfaces. The other is that the reaction between potassium and silica in the bottom ash binds part of the potassium meaning that it is not available for reaction with chlorine or sulphur to form KCl or K{sub 2}SO{sub 4}. Both phases are potentially troublesome because they can condense of surfaces to form a sticky layer onto which fly ash particles can adhere and by inducing corrosion beneath the deposit. It appears that in the studied

  16. The Impact of Pollution Charges, Ash Handling and Carbon Dioxide on the Cost Competitiveness of the Fuel Sources Used for Energy Production in Estonia

    Science.gov (United States)

    Latisov, Eduard; Kleesmaa, Juri; Siirde, Andres

    2010-01-01

    The goal of this paper is to estimate the effects of pollution charges, ash handling and of the carbon dioxide quota trade on the competitiveness of natural gas, oil shale, peat and wood chips in Estonia for 2010 and 2015. The pollution charges and levels are calculated based on the Environmental Charges Act, and Regulations No 99/2004 and No 94/2004 of the Estonian Minister of the Environment. The calculations show a considerable change in the cost competitiveness of fuels. Fuel related costs of the fossil fuels with high CO2 emission factors and other environmental impacts may be doubled.

  17. Impact of nongray multiphase radiation in pulverized coal combustion

    Science.gov (United States)

    Roy, Somesh; Wu, Bifen; Modest, Michael; Zhao, Xinyu

    2016-11-01

    Detailed modeling of radiation is important for accurate modeling of pulverized coal combustion. Because of high temperature and optical properties, radiative heat transfer from coal particles is often more dominant than convective heat transfer. In this work a multiphase photon Monte Carlo radiation solver is used to investigate and to quantify the effect of nongray radiation in a laboratory-scale pulverized coal flame. The nongray radiative properties of carrier phase (gas) is modeled using HITEMP database. Three major species - CO, CO2, and H2O - are treated as participating gases. Two optical models are used to evaluate radiative properties of coal particles: a formulation based on the large particle limit and a size-dependent correlation. Effect of scattering due to coal particle is also investigated using both isotropic scattering and anisotropic scattering using a Henyey-Greenstein function. Lastly, since the optical properties of ash is very different from that of coal, the effect of ash content on the radiative properties of coal particle is examined. This work used Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number ACI-1053575.

  18. Ash Properties of Alternative Biomass

    DEFF Research Database (Denmark)

    Capablo, Joaquin; Jensen, Peter Arendt; Pedersen, Kim Hougaard

    2009-01-01

    The ash behavior during suspension firing of 12 alternative solid biofuels, such as pectin waste, mash from a beer brewery, or waste from cigarette production have been studied and compared to wood and straw ash behavior. Laboratory suspension firing tests were performed on an entrained flow...... analysis into three main groups depending upon their ash content of silica, alkali metal, and calcium and magnesium. To further detail the biomass classification, the relative molar ratio of Cl, S, and P to alkali were included. The study has led to knowledge on biomass fuel ash composition influence...... on ash transformation, ash deposit flux, and deposit chlorine content when biomass fuels are applied for suspension combustion....

  19. Advanced char burnout models for the simulation of pulverized coal fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    T. Severin; S. Wirtz; V. Scherer [Ruhr-University, Bochum (Germany). Institute of Energy Plant Technology (LEAT)

    2005-07-01

    The numerical simulation of coal combustion processes is widely used as an efficient means to predict burner or system behaviour. In this paper an approach to improve CFD simulations of pulverized coal fired boilers with advanced coal combustion models is presented. In simple coal combustion models, first order Arrhenius rate equations are used for devolatilization and char burnout. The accuracy of such simple models is sufficient for the basic aspects of heat release. The prediction of carbon-in-ash is one aspect of special interest in the simulation of pulverized coal fired boilers. To determine the carbon-in-ash levels in the fly ash of coal fired furnaces, the char burnout model has to be more detailed. It was tested, in how far changing operating conditions affect the carbon-in-ash prediction of the simulation. To run several test cases in a short time, a simplified cellnet model was applied. To use a cellnet model for simulations of pulverized coal fired boilers, it was coupled with a Lagrangian particle model, used in CFD simulations, too. 18 refs., 5 figs., 5 tabs.

  20. Effect of Additives and Fuel Blending on Emissions and Ash-Related Problems from Small-Scale Combustion of Reed Canary Grass

    Directory of Open Access Journals (Sweden)

    Sébastien Fournel

    2015-07-01

    Full Text Available Agricultural producers are interested in using biomass available on farms to substitute fossil fuels for heat production. However, energy crops like reed canary grass contain high nitrogen (N, sulfur (S, potassium (K and other ash-forming elements which lead to increased emissions of gases and particulate matter (PM and ash-related operational problems (e.g., melting during combustion. To address these problematic behaviors, reed canary grass was blended with wood (50 wt% and fuel additives (3 wt% such as aluminum silicates (sewage sludge, calcium (limestone and sulfur (lignosulfonate based additives. When burned in a top-feed pellet boiler (29 kW, the four blends resulted in a 17%–29% decrease of PM concentrations compared to pure reed canary grass probably because of a reduction of K release to flue gas. Nitrogen oxides (NOx and sulfur dioxide (SO2 emissions varied according to fuel N and S contents. This explains the lower NOx and SO2 levels obtained with wood based products and the higher SO2 generation with the grass/lignosulfonate blend. The proportion of clinkers found in combustion ash was greatly lessened (27%–98% with the use of additives, except for lignosulfonate. The positive effects of some additives may allow agricultural fuels to become viable alternatives.

  1. Direct Conversion of Chemically De-Ashed Coal in Fuel Cells (II)

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J F

    2005-07-25

    We review the technical challenges associated with the production and use of various coal chars in a direct carbon conversion fuel cell. Existing chemical and physical deashing processes remove material below levels impacting performance at minimal cost. At equilibrium, sulfur entrained is rejected from the melt as COS in the offgas.

  2. Technology for the Recovery of Fuel and Adsorbent Carbons from Coal Burning Utility Ash Ponds and Landfills

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Groppo; T.L. Robl

    2005-09-30

    marketable lightweight aggregate and recover a high-grade fuel product. Spiral concentration provided acceptable grade lightweight aggregate with yields of only 10 to 20%. Incorporating a sieve bend into the process to recover coarse, porous ash particles from the outside race of the spirals increased aggregate yield to as high as 75%, however, the carbon content of the aggregate also increased. An opening size of 28 mesh on the sieve bend appeared to be sufficient. Lightweight concrete blocks (28 to 32 lbs) were produced from bottom ash and results show that acceptable strength could be attained with a cement/concrete ratio as low as 1/4. A mobile Proof-of-Concept (POC) field unit was designed and fabricated to meet the processing objectives of the project. The POC plant consisted of two trailer-mounted modules and was completely self sufficient with respect to power and water requirements. The POC unit was hauled to Coleman Station and operated at a feed rate of 2 tph. Results showed that the spirals operated similarly to previous pilot-scale operations and a 500 lb composite sample of coarse carbon was collected with a grade of 51.7% C or 7279 Btu/lb. Flotation results compared favorably with release analysis and 500 lbs of composite froth product was collected with a grade of 35% C or 4925 Btu/lb. The froth product was dewatered to 39% moisture with vacuum filtration. Pan pelletization and briquetting were evaluated as a means of minimizing handling concerns. Rotary pan pelletization produced uniform pellets with a compressive strength of 4 lbf without the use of any binder. Briquettes were produced by blending the coarse and fine carbon products at a ratio of 1:10, which is the proportion that the two products would be produced in a commercial operation. Using 3% lime as a binder produced the most desirable briquettes with respect to strength, attrition and drop testing. Additionally, the POC carbon products compared favorably with commercial activated carbon when used

  3. Technology for the Recovery of Fuel and Adsorbent Carbons from Coal Burning Utility Ash Ponds and Landfills

    Energy Technology Data Exchange (ETDEWEB)

    J.G. Groppo; T.L. Robl

    2005-09-30

    marketable lightweight aggregate and recover a high-grade fuel product. Spiral concentration provided acceptable grade lightweight aggregate with yields of only 10 to 20%. Incorporating a sieve bend into the process to recover coarse, porous ash particles from the outside race of the spirals increased aggregate yield to as high as 75%, however, the carbon content of the aggregate also increased. An opening size of 28 mesh on the sieve bend appeared to be sufficient. Lightweight concrete blocks (28 to 32 lbs) were produced from bottom ash and results show that acceptable strength could be attained with a cement/concrete ratio as low as 1/4. A mobile Proof-of-Concept (POC) field unit was designed and fabricated to meet the processing objectives of the project. The POC plant consisted of two trailer-mounted modules and was completely self sufficient with respect to power and water requirements. The POC unit was hauled to Coleman Station and operated at a feed rate of 2 tph. Results showed that the spirals operated similarly to previous pilot-scale operations and a 500 lb composite sample of coarse carbon was collected with a grade of 51.7% C or 7279 Btu/lb. Flotation results compared favorably with release analysis and 500 lbs of composite froth product was collected with a grade of 35% C or 4925 Btu/lb. The froth product was dewatered to 39% moisture with vacuum filtration. Pan pelletization and briquetting were evaluated as a means of minimizing handling concerns. Rotary pan pelletization produced uniform pellets with a compressive strength of 4 lbf without the use of any binder. Briquettes were produced by blending the coarse and fine carbon products at a ratio of 1:10, which is the proportion that the two products would be produced in a commercial operation. Using 3% lime as a binder produced the most desirable briquettes with respect to strength, attrition and drop testing. Additionally, the POC carbon products compared favorably with commercial activated carbon when used

  4. Corrosion behavior of Fe-Si metallic coatings added with NiCrAlY in an environment of fuel oil ashes at 700 C

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Bravo, V.M.; Porcayo-Calderon, J.; Romero-Castanon, T. [Instituto de Investigaciones Electricas, Gerencia de Procesos Termicos., Av. Reforma 113, C.P. 62490 Col. Palmira. Temixco. Morelos (Mexico); Dominguez-Patino, G.; Gonzalez-Rodriguez, J.G. [U.A.E.M. Centro de Investigaciones en Ingenieria y Ciencias Aplicadas., Av. Universidad 1001, C.P. 62210, Col. Chamilpa. Cuernavaca, Morelos (Mexico)

    2005-07-01

    Electrochemical potentiodynamic polarization curves and immersion tests for 300 h at 700 C in a furnace have been used to evaluate the corrosion resistance of Fe-Si metallic coatings added with up to 50 wt.% of NiCrAIY. The corrosive environment was fuel oil ashes from a steam generator. The composition of fuel oil ashes includes high content of vanadium, sodium and sulfur. The results obtained show that only the addition of 20 wt.% NiCrAlY to the Fe-Si coating improves its corrosion resistance. The behavior of all tested coatings is explained by the results obtained from the analysis of every coating using electron microscopy and energy dispersive X-ray analysis. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  5. Activation of Rejected Fly Ash Using Flue Gas Desulphurization (FGD) Sludge

    Institute of Scientific and Technical Information of China (English)

    QIAO Xiu-chen; POON Chisun; LIN Zong-shou

    2003-01-01

    Low-grade fly ash ( rejected fly ash, rFA ), a significant portion of the pulverized fuel ash ( PFA ) produced from coal-fired power plauts and rejected from the ash classifying process, remains unused due to its high carbon content and large particle size ( > 45μm ). But it is thonght that the rejected ash may have potential uses in chemical stabilization/solidification ( S/S ) processes which need relatively lower strengths and a lower chemical reactivity. Flue Gas Desulphurisation ( FGD ) sludge is a by-product of air pollution control equipment in coal fired power plants whose chemical composition is mainly gypsum. As there is no effective usage of both of these two ntaterials , it is of interest to research on the possible octtivation of rFA using FGD . This paper presents experimental results of a study on the properties of rFA activated by the FGD in rFA-cement pastes. Different percetages of FGD were added into the mix to study the effects of the FGD on the reaction of the rFA blended cement pastes.The results show that FGD takes effect as an activator only at late curing ages. Adding Ca ( OH)2 enhances the effect of FGD on activating the hytration of rFA. Also, 10% FGD by weight of rFA is the optimal addition in the rFA-cement pastes. The results of the compressive strength measurements correlate well with the porosity results.

  6. Investigation of the particle size distribution and particle density characteristics of Douglas fir hogged fuel fly ash collected under known combustion conditions. Technical Progress Report No. 2

    Energy Technology Data Exchange (ETDEWEB)

    Lang, A.J.; Junge, D.C.

    1978-12-01

    The increased interest in wood as a fuel source, coupled with the increasing demand to control the emission generated by wood combustion, has created a need for information characterizing the emissions that occur for given combustion conditions. This investigation characterizes the carbon char and inorganic fly ash size and density distribution for each of thirty-eight Douglas fir bark samples collected under known conditions of combustion.

  7. The Impact of Pollution Charges, Ash Handling and Carbon Dioxide on the Cost Competitiveness of the Fuel Sources Used for Energy Production in Estonia

    OpenAIRE

    Latisov, E; Kleesmaa, J; A. Siirde

    2010-01-01

    The goal of this paper is to estimate the effects of pollution charges, ash handling and of the carbon dioxide quota trade on the competitiveness of natural gas, oil shale, peat and wood chips in Estonia for 2010 and 2015. The pollution charges and levels are calculated based on the Environmental Charges Act, and Regulations No 99/2004 and No 94/2004 of the Estonian Minister of the Environment. The calculations show a considerable change in the cost competitiveness of fuels. Fuel relat...

  8. Numerical study of co-firing pulverized coal and biomass inside a cement calciner.

    Science.gov (United States)

    Mikulčić, Hrvoje; von Berg, Eberhard; Vujanović, Milan; Duić, Neven

    2014-07-01

    The use of waste wood biomass as fuel is increasingly gaining significance in the cement industry. The combustion of biomass and particularly co-firing of biomass and coal in existing pulverized-fuel burners still faces significant challenges. One possibility for the ex ante control and investigation of the co-firing process are computational fluid dynamics (CFD) simulations. The purpose of this paper is to present a numerical analysis of co-firing pulverized coal and biomass in a cement calciner. Numerical models of pulverized coal and biomass combustion were developed and implemented into a commercial CFD code FIRE, which was then used for the analysis. Three-dimensional geometry of a real industrial cement calciner was used for the analysis. Three different co-firing cases were analysed. The results obtained from this study can be used for assessing different co-firing cases, and for improving the understanding of the co-firing process inside the calculated calciner.

  9. Utilization of Palm Oil Fuel Ash and Rice Husks in Unfired Bricks for Sustainable Construction Materials Development

    Directory of Open Access Journals (Sweden)

    Saleh A.M

    2014-01-01

    Full Text Available The production of sustainable construction component could prevent and control the pollution and environmental degradation in Malaysia. This is a key area in Malaysia’s Green Strategies (Ministry of Science, Technology and the environment, 2002. This paper reports on the laboratory investigation to establish the potential of utilizing Palm Oil Fuel Ash (POFA and Rice Husk (RH in developing green construction components. Malaysian Palm Oil Council (MPOC reported that currently Malaysia’s contribution to world palm oil production is 39% and has taken 44% of world exports. Consequently it will increase the POFA production in palm oil manufacturing and this waste sometimes dispose in open area near the factory. On the other hand Malaysia also producing more 300k hectares of paddy production, thus rice husk is also a concern as an agricultural waste. The research objective is to study on the potential of utilizing of agricultural waste in developing of green bricks. This research involved laboratory investigations. In this research 2% - 10% of POFA and 1% - 5% RH were used in the mix composition of the brick’s weight. Addition of POFA was aimed to reduce the cement usage and RH was added to reduce sand in the bricks. The bricks were manually pressed in Materials Laboratory in Faculty of Architecture, Planning and Surveying, UiTM Shah Alam. The result showed that the addition of POFA and RH are able to reduce the density but in contrast the compressive strength were decrease compare to the control unit.

  10. Alkali activation of recovered fuel-biofuel fly ash from fluidised-bed combustion: Stabilisation/solidification of heavy metals.

    Science.gov (United States)

    Yliniemi, Juho; Pesonen, Janne; Tiainen, Minna; Illikainen, Mirja

    2015-09-01

    Recovered fuel-biofuel fly ash from a fluidized bed boiler was alkali-activated and granulated with a sodium-silicate solution in order to immobilise the heavy metals it contains. The effect of blast-furnace slag and metakaolin as co-binders were studied. Leaching standard EN 12457-3 was applied to evaluate the immobilisation potential. The results showed that Ba, Pb and Zn were effectively immobilised. However, there was increased leaching after alkali activation for As, Cu, Mo, Sb and V. The co-binders had minimal or even negative effect on the immobilisation. One exception was found for Cr, in which the slag decreased leaching, and one was found for Cu, in which the slag increased leaching. A sequential leaching procedure was utilized to gain a deeper understanding of the immobilisation mechanism. By using a sequential leaching procedure it is possible fractionate elements into watersoluble, acid-soluble, easily-reduced and oxidisable fractions, yielding a total 'bioavailable' amount that is potentially hazardous for the environment. It was found that the total bioavailable amount was lower following alkali activation for all heavy metals, although the water-soluble fraction was higher for some metals. Evidence from leaching tests suggests the immobilisation mechanism was chemical retention, or trapping inside the alkali activation reaction products, rather than physical retention, adsorption or precipitation as hydroxides.

  11. Alkali activated solidification/stabilisation of air pollution control residues and co-fired pulverised fuel ash.

    Science.gov (United States)

    Shirley, Robin; Black, Leon

    2011-10-30

    This paper examines the potential treatment by solidification/stabilisation (S/S) of air pollution control (APC) residues using only waste materials otherwise bound for disposal, namely a pulverised fuel ash (PFA) from a co-fired power station and a waste caustic solution. The use of waste materials to stabilise hazardous wastes in order to meet waste acceptance criteria (WAC) would offer an economical and efficient method for reducing the environmental impact of the hazardous waste. The potential is examined against leach limits for chlorides, sulphates and total dissolved solids, and compressive strength performance described in the WAC for stable non-reactive (SNR) hazardous waste landfill cells in England and Wales. The work demonstrates some potential for the treatment, including suitable compressive strengths to meet regulatory limits. Monolithic leach results showed good encapsulation compared to previous work using a more traditional cement binder. However, consistent with previous work, SNR WAC for chlorides was not met, suggesting the need for a washing stage. The potential problems of using a non-EN450 PFA for S/S applications were also highlighted, as well as experimental results which demonstrate the effect of ionic interactions on the mobility of phases during regulatory leach testing.

  12. Impact of Blending on Strength Distribution of Ambient Cured Metakaolin and Palm Oil Fuel Ash Based Geopolymer Mortar

    Directory of Open Access Journals (Sweden)

    Taliat Ola Yusuf

    2014-01-01

    Full Text Available This paper investigates the influence of blending of metakaolin with silica rich palm oil fuel ash (POFA on the strength distribution of geopolymer mortar. The broadness of strength distribution of quasi-brittle to brittle materials depends strongly on the existence of flaws such as voids, microcracks, and impurities in the material. Blending of materials containing alumina and silica with the objective of improving the performance of geopolymer makes comprehensive characterization necessary. The Weibull distribution is used to study the strength distribution and the reliability of geopolymer mortar specimens prepared from 100% metakaolin, 50% and 70% palm and cured under ambient condition. Mortar prisms and cubes were used to test the materials in flexure and compression, respectively, at 28 days and the results were analyzed using Weibull distribution. In flexure, Weibull modulus increased with POFA replacement, indicating reduced broadness of strength distribution from an increased homogeneity of the material. Modulus, however, decreased with increase in replacement of POFA in the specimens tested under compression. It is concluded that Weibull distribution is suitable for analyses of the blended geopolymer system. While porous microstructure is mainly responsible for flexural failure, heterogeneity of reaction relics is responsible for the compression failure.

  13. Production and Characterisation of Microfine Sized Palm Oil Fuel Ash (POFA Originated from Bau, Lundu Palm Oil Mill

    Directory of Open Access Journals (Sweden)

    Ahmadi R.

    2017-01-01

    Full Text Available This paper investigates an effective and economical way for laboratory scale production of micro fine sized palm oil fuel ash (POFA using an electric powder grinder. The raw POFA obtained from the palm oil mill is initially grinded by using Los Angeles abrasion machine, and then sieved using 150 μm sieve before it is burned in a furnace at 500°C. The burned POFA is then grinded using electric powder grinder to obtain the targeted micro fine sized. The physical, morphological and chemical properties of the micro fine sized POFA produced are analysed in the form of cement paste using Particle Size Analyzer (PSA, nitrogen sorption by using BET method, Fourier Transform Infrared Spectroscopy (FT-IR and Scanning Electron Microscopy (SEM with Energy Dispersive Spectroscopy (EDS. The results show that 96% micro fine sized POFA is produced when using the optimum grinding process. The microstructural analyses of cement paste with 20% micro fine sized POFA replacement give the optimum results that contribute to higher compressive strength. The overall results of this research show that the optimum grinding process by using electric powder grinder is relevant and can be used as pioneering work in the concrete production industry.

  14. Oil shale fueled FBC power plant - ash deposits and fouling problems

    Energy Technology Data Exchange (ETDEWEB)

    O. Yoffe; A. Wohlfarth; Y. Nathan; S. Cohen; T. Minster [Geological Survey of Israel, Jerusalem (Israel)

    2007-12-15

    41 MWth oil shale fired demonstration power plant was built in 1989 by PAMA in Mishor Rotem, Negev, Israel. The raw material for the plant is the local 'oil shale', which is in fact organic-rich marl. Since then, and until today, the unit is operated at high reliability and availability. At first, heavy soft fouling occurred due to the Circulating Fluidized Bed Combustion (CFBC) mode of operation, which caused a considerable reduction in the heat transfer coefficient of the heat exchangers. By going over to the Fluidized Bed Combustion (FBC) mode of operation the soft fouling phenomenon stopped at once, the heat transfer coefficient improved, and the power plant could be operated at its designed values. After five months of operation at the FBC mode the boiler had to be shut down because Hard Deposits (HD) blocked physically the passes in the boiler. These deposits could be removed only with the help of mechanical devices. During the first two years the boiler had to be stopped, at least, three times a year for deposit cleaning purposes. Research conducted at the plant and in the laboratories of the Geological Survey of Israel enabled us to understand the mechanism of formation of these deposits. The results showed that the HD are formed in two stages: (1) Deposition of very fine ash particles on the pipes of the boiler, as a result of the impact of larger particles on the pipes. The fine particles adhere to the pipes and to each other, and step by step build the deposit. The growth of the deposit on the pipe surface is always perpendicular to the particles flow direction. (2) The deposits harden due to chemical reactions. 17 refs., 14 figs., 5 tabs.

  15. Efficiency of using direct-flow burners and nozzles in implementation of dry-bottom ash removal at the TPP-210A boiler furnace

    Science.gov (United States)

    Arkhipov, A. M.; Kanunnikov, A. A.; Kirichkov, V. S.; Prokhorov, V. B.; Fomenko, M. V.; Chernov, S. L.

    2017-02-01

    In reconstruction of operating pulverized coal-fired boilers, one of the main factors is the choice of a method for slag removal: dry bottom ash removal (DBAR) or slag-tap removal (STR). In this case, ecological and economic aspects should be taken into account, and also the early ignition of pulverized coal fuel, the reliability of operation of the furnace walls in the mode without slagging, and the stability of slag removal should be provided. In this work, issues of changeover of the pulverized coal-fired boilers of the TPP-210A type from the STR mode to the DBAR mode are considered. As of today, the main problems during the operation of these boilers are the high emissions of nitrogen oxides together with flue gases into the atmosphere and the appropriated payoffs, a small range of loads available, the necessity of stabilization of the pulverizedcoal flame sustainability by using the highly reactive fuel, large mechanical fuel underburning, etc. Results of studying aerodynamics of a furnace with DBAR obtained in the process of physical simulation are given; technical solutions and preliminary design (configuration of burners and nozzles in the boiler furnace, conceptual design of the pulverized coal burner, configuration of TPP-210A boiler with the low heat liberation of furnace cross-section and volumetric heat release) are set forth, which are associated with the optimization of aerodynamics of furnace volume, when the direct-flow burners and nozzles are used, and with organization of the efficient staged combustion of solid fuel. Two versions of possible modernization of a boiler unit are considered. Under conditions of the planned increase in the steam production capacity, the most promising measures are as follows: the DBAR implementation with reducing heat releases of the cross-section and volume of the furnace approximately by half, the installation of the direct-flow burners and nozzles with injection of recirculation gases into the active combustion

  16. A kinetic model of carbon burnout in pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, R.; Jian-Kuan Sun; Lunden, M. [Brown University, Providence, RI (United States). Division of Engineering

    1998-04-01

    The degree of carbon burnout is an important operating characteristic of full-scale suspension-fired coal combustion systems affecting boiler efficiency, electrostatic precipitator operation and the value of fly ash as a saleable product. Prediction of carbon loss requires special char combustion kinetics valid through the very high conversions targeted in industry (typically {gt} 99.5%), and valid for a wide-range of particle temperature histories occurring in full-scale furnaces. The paper presents high-temperature kinetic data for five coal chars in the form of time-resolved burning profiles that include the late stages of combustion. It then describes the development and validation of the Carbon Burnout Kinetic Model (CBK), a coal-general kinetics package that is specifically designed to predict the total extent of carbon burnout and ultimate fly ash carbon content for prescribed temperature/oxygen histories typical of pulverized coal combustion systems. The model combines the single-film treatment of cha oxidation with quantitative descriptions of thermal annealing, statistical kinetics, statistical densities, and ash inhibition in the late stages of combustion. In agreement with experimental observations, the CBK model predicts (1) low reactivities for unburned carbon residues extracted from commercial ash samples, (2) reactivity loss in the late stages of laboratory combustion, (3) the observed sensitivity of char reactivity to high-temperature heat treatment on second and subsecond time scales, and (4) the global reaction inhibition by mineral matter in the late stages of combustion observed in single-particle imaging studies. The model ascribes these various char deactivation phenomena to the combined effects of thermal annealing, ash inhibition, and the preferential consumption of more reactive particles (statistical kinetics), the relative contributions of which vary greatly with combustion conditions. 39 refs., 4 figs., 4 tabs., 1 app.

  17. Combustion characterization of beneficiated coal-based fuels. Quarterly report No. 17, April--June 1993

    Energy Technology Data Exchange (ETDEWEB)

    Chow, O.K.; Nsakala, N.Y.

    1993-08-01

    Pittsburgh Energy Technology Center of the US Department of Energy has contracted with Combustion Engineering, Inc. (CE) to perform a five-year project on ``Combustion Characterization of Beneficiated Coal-Based Fuels.`` The beneficiated coals are produced by other contractors under the DOE Coal Preparation Program. Several contractor-developed advanced coal cleaning processes are run at pilot-scale cleaning facilities to produce 20-ton batches of fuels for shipment to CE`s laboratory in Windsor, Connecticut. CE then processes the products into either a coal-water fuel (CWF) or a dry microfine pulverized coa1 (DMPC) form for combustion testing. The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of BCFs influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. The technical approach used to develop the technical data includes: bench-scale fuel property, combustion, and ash deposition tests; pilot-scale combustion and ash effects tests; and full-scale combustion tests. During the third quarter of 1993, the following technical progress was made: Completed modeling calculations of coal mineral matter transformations, deposition behavior, and heat transfer impacts of six test fuels; and ran pilot-scale tests of Upper Freeport feed coal, microagglomerate product, and mulled product.

  18. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt;

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome...... ash deposits which contain significant concentrations of alkali, and earth-alkali metals. The specific composition of biomass deposits give different characteristics as compared to coal ash deposits, i.e. different physical significance of the deposition mechanisms, lower melting temperatures, etc....... Low melting temperatures make straw ashes especially troublesome, since their stickiness is higher at lower temperatures, compared to coal ashes. Increased stickiness will eventually lead to a higher collection efficiency of incoming ash particles, meaning that the deposit may grow even faster...

  19. Analysis of sewage sludge ashes from air and oxy-fuel combustion in a circulating fluidized-bed

    Directory of Open Access Journals (Sweden)

    Magdziarz Aneta

    2016-01-01

    Full Text Available The ashes from sewage sludge combustion in air versus O2/CO2 atmospheres with oxygen concentrations in the range of 21–40% vol. at temperature of 850°C in a 12 kW bench-scale CFB combustor were characterised. The chemical and phase composition of ashes were studied by XRF and XRD. The morphology of studied ashes were examined by SEM method. The slagging and fouling indices were calculated to study the deposition tendencies of ash. The thermal behaviour of ashes was studied by TG-DSC techniques, focusing on the mass loss and thermic effects with the increasing of temperature up to 1200°C.

  20. Naturally occurring radioactive materials (NORM) in ashes from a fuel-oil power plant in Cienfuegos, Cuba, and the associated radiation hazards.

    Science.gov (United States)

    Alonso-Hernández, C M; Bernal-Castillo, J; Morera-Gómez, Y; Guillen-Arruebarrena, A; Cartas-Aguila, H A; Acosta-Milián, R

    2014-03-01

    The radioactivity of NORM was measured in ashes collected from a fuel-oil power plant in Cienfuegos, Cuba, using an HPGe gamma-ray spectrometer. The (226)Ra, (210)Pb, (40)K, (232)Th and (238)U activity concentrations reached 240, 77, 59, 70 and 15 Bq kg(-1), respectively. The potential radiological hazard of these residuals was assessed. The radium equivalent activities of the samples varied from 54 to 345 Bq kg(-1). The gamma index was calculated to be lower than that of the reference values, and the gamma absorbed dose rate was higher than the average reported for the earth's crust; however, the assessed annual effective dose was slightly lower than the annual effective dose limit for public, i.e. 1 mSv. Therefore, these bottom ashes were not dramatically enriched with radionuclides and may be used as an additive for building materials without restrictions from a radiological protection point of view.

  1. Fly ash quality and utilization

    Energy Technology Data Exchange (ETDEWEB)

    Barta, L.E.; Lachner, L.; Wenzel, G.B. [Inst. for Energy, Budapest (Hungary); Beer, M.J. [Massachusetts Inst. of Technology, Cambridge, MA (United States)

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  2. Investigation of migratory bird mortality associated with exposure to Soda Ash Mine tailings water in southwestern Wyoming

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Soda ash is a pulverized mineral, commonly referred to as “trona”, and harvested from underground deposits in southwestern Wyoming. Four companies own 5 mining...

  3. Bromine and Chlorine in Aerosols and Fly Ash when Co-Firing Solid Recovered Fuel, Spruce Bark and Paper Mill Sludge in a 80MWth BFB Boiler

    Science.gov (United States)

    Vainikka, P.; Silvennoinen, J.; Yrjas, P.; Frantsi, A.; Hietanen, L.; Hupa, M.; Taipale, R.

    Aerosol and fly ash sampling was carried out at a 80MWth bubbling fluidised bed (BFB) boiler plant co-firing solid recovered fuel (SRF), spruce bark and paper mill wastewater sludge in two experimental conditions. The SRF-Bark ratio in the fuel mix was kept constant at 50%-50% on dry mass basis in both experiments but two sludge proportions were used: 15% and 4% on dry mass basis. Aerosol samples were collected from the superheater region of the boiler furnace and fly ash from the electrostatic precipitator (ESP). Na, K, Cl and S were found to be in mainly water soluble compounds in the aerosols sampled by means of a Dekati type Low Pressure Impactor (DLPI). Bromine was found in several weight percentages in aerosols and it was amongst the main elements in some of the samples collected. Bromine is assumed to mainly originate from flame retarded plastics and textiles in the SRF. According to the measurements, the fate of Br seems to be analogous to the other main halogen, Cl, and its conversion from fuel to aerosols was high, indicating a strong tendency to form bromine salts.

  4. Free swell characteristics of PCC bottom ash-bentonite mixtures with curing for use as fill or liner material

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.; Burrus, N. [South Illinois University, Carbondale, IL (United States). Dept. for Civil & Environmental Engineering

    2005-07-01

    Bottom ash is a coal combustion product (CCP) obtained from burning of pulverized coal to produce electricity. Most of the bottom ash from pulverized coal combustion (PCC) plants is disposed of in landfills and/or ash ponds. Over the last decade, there has been increased attention aimed toward the use of PCC bottom ash in geotechnical applications. The particle size distribution of pulverized coal combustion (PCC) bottom ash is similar to that of natural sand. Naturals and is commonly used in the construction industry in place of cohesive soils by adding admixtures to amend its properties. Several studies have been completed to determine the properties of bottom ash amended with bentonite. However, due to significant volume change characteristics of bentonite, soils or similar granular materials amended with it need to be evaluated for their swelling behavior. In addition, studies all bottom ash-bentonite mixtures have shown that strength and stiffness characteristics of these mixtures change significantly with curing. Therefore, in order to evaluate the use of bottom ash as a fill or landfill liner material, this study was initiated to investigate the effect of curing and moisture content on the swelling: characteristics of pulverized coal combustion bottom ash amended with bentonite. Bottom ash specimens containing 15 and 20 percent bentonite and prepared at 14, 16 and 18 percent initial moisture content were tested in this investigation. Results presented show the swelling characteristics of bottom ash-bentonite mixtures with curing age up to 60 days.

  5. Formation of PCDD/PCDF - Effect of fuel and fly ash composition on the formation of PCDD/PCDF in the co-combustion of refuse-derived and packaging-derived fuels

    Energy Technology Data Exchange (ETDEWEB)

    Manninen, H. [Neste Oy, Corporate Technology, Porvoo (Finland); Perkioe, A. [Neste Oy, Corporate Technology, Porvoo (Finland); Vartiainen, T. [National Public Health Inst., Kuopio (Finland). Dept. of Environmental Health]|[Kuopio Univ. (Finland). Dept. of Envitonmental Sciences; Ruuskanen, J. [Kuopio Univ. (Finland). Dept. of Envitonmental Sciences

    1996-12-31

    One option of recycling used contaminated packaging is to recover its high energy content. This can be performed in a normal multifuel power plant by co-combustion of packaging-derived fuel (PDF) or refuse-derived fuel (RDF) with fossil fuels, such as coal or peat. This work includes the results of 17 co-combustion tests and an evaluation of the results by the Principal Component Analysis (PCA) and the Partial Least Squares Projections to Latent Structures (PLS). PCA and PLS calculations showed that especially Pb, but also Cr, and Cu correlated with lower chlorinated furans (PCDFs) in the fly ash. Correlation between Sn and lower chlorinated dioxins (PCDDs) in the fly ash was also noticed. CO and PAH emission in the flue gas correlated with total PCDD/Fs in the flue gas. In a real full-scale combustion process, a single parameter in fuel, flue gas or a combustion parameter did not provide a guide to PCDD/F formation or to a level of the total PCDD/F emission, but correlations between different parameters and PCDD/Fs could be found. Although PDFs and RDF had catalytic heavy metals and chlorine, the co-combustion results showed that they can be co-combusted with peat and coal in a fluidzed-bed boiler at least up to 26% with very low total PCDD and PCDF emissions. (orig.)

  6. A New Agro/Forestry Residues Co-Firing Model in a Large Pulverized Coal Furnace: Technical and Economic Assessments

    Directory of Open Access Journals (Sweden)

    Shien Hui

    2013-08-01

    Full Text Available Based on the existing biomass co-firing technologies and the known innate drawbacks of dedicated biomass firing, including slagging, corrosion and the dependence on fuel, a new model of agro/forestry residue pellets/shreds and coal co-fired in a large Pulverized Coal (PC furnace was proposed, and the corresponding technical and economic assessments were performed by co-firing testing in a 300 MW PC furnace and discounted cash flow technique. The developed model is more dependent on injection co-firing and combined with co-milling co-firing. Co-firing not only reduces CO2 emission, but also does not significantly affect the fly ash use in cement industry, construction industry and agriculture. Moreover, economic assessments show that in comparison with dedicated firing in grate furnace, agro/forestry residues and coal co-firing in a large PC furnace is highly economic. Otherwise, when the co-firing ratio was below 5 wt%, the boiler co-firing efficiency was 0.05%–0.31% higher than that of dedicated PC combustion, and boiler efficiencies were about 0.2% higher with agro/forestry residues co-firing in the bottom and top burner systems than that in a middle burner system.

  7. Reduced ash-related operational problems by co-combustion peat and agricultural fuels; Minskade askrelaterade driftsproblem genom inblandning av torv i aakerbraenslen

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Marcus; Bostroem, Dan; Skoglund, Nils; Grimm, Alejandro; Boman, Christoffer; Kofod-Hansen, Marie

    2010-06-15

    The objectives of the project were: To determine the admixing levels for different peat classes to various energy crops (straw, Salix and Reed canary grass) that are required to reach positive effects regarding slagging, deposit formation/(high temperature corrosion) and bed agglomeration; and, To demonstrate the possibilities to reduce the occurrence of ash related operational problems in combustion of energy crops upon admixing peat. Operational experiences and research of effects of co-firing peat and energy crops are scarce. Some previous tests in bench scale indicated though, on a strong reduction of the agglomeration tendency and lowering of the agglomeration temperature for straw and Salix at a peat admixing level corresponding to 15 - 20 weight% (on DS basis). A reduction in the amount of emitted fine particles was also observed in these experiments. However, care must be taken in the choice of peat. Some Carex dominated peats with high Si contents may cause problems with slagging. Another conclusion from the mentioned bench scale tests was that peats with relative high Ca/Si ratios should be selected to minimize the risk of slagging and bed agglomeration. Thermochemical modelling was performed to determine the effects of peat admixture, on slagging-, deposit formation- (corrosion)- and bed agglomeration tendencies during combustion of straw, willow and reed canary grass with high and low ash content. These results and previously conducted bench scale experiments were used as a basis for determining combinations of fuel and peat admixtures for the demonstration experiments. The calculations were performed with admixing levels of 0-, 5-, 15, 25-, and 40 weight% (on DS basis) of four peat samples to the investigated four crop fuels. The used peat samples were typical carex-containing Swedish peat with differences in e.g. silicon-, calcium- and sulfur contents. A number of the model calculations were qualitatively validated against previously conducted

  8. Pilot plant development of a new catalytic process for improved electrostatic separation of fly ash in coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Olivares del Valle, J.; Martinez, L.S.; Baum, B.M.; Galeano, V.C. [Universidad de Sevilla (Spain)

    1995-12-31

    The design and operation of pulverized-coal-fired power plants (PCFPP) are usually regarded as fuel range in terms of sulphur and ash contents. These units may give severe environmental problems of fly ash emissions as a result of lower SO{sub 3} contents in the flue gas (FG) because the electrical resistivity of the solid particles is correspondingly lower, with consequent adverse effects on electrostatic precipitator (ESP) efficiency. More stringent air pollution laws cause many power companies to burn lower sulphur coal under boilers in plants that formerly burned higher S coal or ran with abnormal operational conditions (only remediable by shutdown and repairs). This presentation of the GASOX process is a contribution to the improvement of existing technology for flue gas conditioning (FGC), which is defined as a control system for (ESP) efficiency in PCFPP.

  9. New computer program plots coal particle size to monitor pulverizer performance

    Energy Technology Data Exchange (ETDEWEB)

    Tartar, A.M. (Univ. of Missouri, St. Louis, MO (United States)); Mueller, W.K. (Union Electric Co., St. Louis, MO (United States)); Marrero, T.R.

    1994-11-01

    Maintaining proper coal particle size and distribution is one of many considerations in achieving efficient combustion performance. Improper pulverizer operation and maintenance can result in an excessive percentage of either coarse coal particles, which tends to increase the amount of unburned carbon in the ash, or fine coal particles, which can limit the throughput of the pulverizer and, if too fine, can affect coal burning rates and residence time in boilers. Traditionally, coal particle size plotting and distribution have been done by hand and required special graphing paper formulated using the Rosin and Rammler equation. Now there is an alternative. This article describes a computerized procedure for plotting the fineness of coal particles after the milling process developed by engineers at Union Electric Co., St. Louis, Mo., and the University of Missouri, Columbia. Known as an ANTAR-UE, this procedure is being used by the Betterment Engineering group at Union Electric to plot mill fineness data.

  10. Simplified process for leaching precious metals from fuel cell membrane electrode assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Shore, Lawrence (Edison, NJ); Matlin, Ramail (Berkeley Heights, NJ)

    2009-12-22

    The membrane electrode assemblies of fuel cells are recycled to recover the catalyst precious metals from the assemblies. The assemblies are cryogenically embrittled and pulverized to form a powder. The pulverized assemblies are then mixed with a surfactant to form a paste which is contacted with an acid solution to leach precious metals from the pulverized membranes.

  11. Pushing the pulverized coal envelope with LEBS

    Energy Technology Data Exchange (ETDEWEB)

    Regan, J.W.; Borio, R.W.; Palkes, M. [and others

    1995-11-01

    In response to challenges from technologies such as IGCC and PFBC, the ABB LEBS Team has proposed removing the barriers to very large advances in environmental and thermal performance of pulverized coal plants. Pulverized coal will continue to be the source of more than half of our electric generation well into the next century and we must develop low-risk low-cost advances that will compete with the claimed performance of other technologies. This paper describes near-term PC technologies for new and retrofit applications which will accomplish this.

  12. Relationship between Particle Size Distribution of Low-Rank Pulverized Coal and Power Plant Performance

    Directory of Open Access Journals (Sweden)

    Rajive Ganguli

    2012-01-01

    Full Text Available The impact of particle size distribution (PSD of pulverized, low rank high volatile content Alaska coal on combustion related power plant performance was studied in a series of field scale tests. Performance was gauged through efficiency (ratio of megawatt generated to energy consumed as coal, emissions (SO2, NOx, CO, and carbon content of ash (fly ash and bottom ash. The study revealed that the tested coal could be burned at a grind as coarse as 50% passing 76 microns, with no deleterious impact on power generation and emissions. The PSD’s tested in this study were in the range of 41 to 81 percent passing 76 microns. There was negligible correlation between PSD and the followings factors: efficiency, SO2, NOx, and CO. Additionally, two tests where stack mercury (Hg data was collected, did not demonstrate any real difference in Hg emissions with PSD. The results from the field tests positively impacts pulverized coal power plants that burn low rank high volatile content coals (such as Powder River Basin coal. These plants can potentially reduce in-plant load by grinding the coal less (without impacting plant performance on emissions and efficiency and thereby, increasing their marketability.

  13. Occurrence and volatility of several trace elements in pulverized coal boiler

    Institute of Scientific and Technical Information of China (English)

    HUANG Ya-ji; JIN Bao-sheng; ZHONG Zhao-ping; XIAO Rui; TANG Zhi-yong; REN Hui-feng

    2004-01-01

    The contents of eight trace elements(Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and flyash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements wereinvestigated, including fly ash diameter, furnace temperature, oxygen content and trace elements' characters. Onecoefficient of Meij was also improved to more directly show element enrichment in combustion products. Theseelements may be classified into three groups according to their distribution: Group 1: Hg, which is very volatile.Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be locatedbetween groups 1 and 2. Cr has properties of both group 1 and 3. In addition, the smaller diameter of fly ash, themore relative enrichment of trace elements( except Mn). The fly ash showed different adsorption mechanisms oftrace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of traceelements(except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen content can not alwaysimprove the volatilization of trace elements. Pb is easier to form chloride than Cd during coal combustion. Traceelements should be classified in accordance with factors.

  14. Ash chemistry in the U-GAS process: industrial medium-Btu fuel gas demonstration-plant program

    Energy Technology Data Exchange (ETDEWEB)

    1979-02-01

    The chemistry of the agglomeration of ash in IGT's U-GAS pilot plant runs on coke, run-of-mine Kentucky coal, and washed Kentucky coal has been investigated. Methods included optical and electron microscopy, chemical analyses, and fusibility tests. There is little difference in elemental composition of the ash among the three feeds. Agglomeration of ash into rounded beads occurred in runs on coke and washed coal through formation of an iron-rich, relatively low-melting matrix in which other ash is embedded. The matrix, a mixture consisting mainly of ferrous aluminum silicate, is formed by reaction of iron oxide with aluminosilicates (clay minerals) of the coal. Iron in coke is in a form suitable for this reaction to proceed. Iron in coal occurs mainly as pyrite, which loses half its sulfur to form ferrous sulfide when the coal is heated to bed temperature; the ferrous sulfide must then be oxidized to ferrous oxide before the reaction with the aluminosilicates can proceed. This oxidation occurred, and the ferrous aluminum silicate was formed in pilot plant tests with washed coal but not in tests with run-of-mine coal; however, the difference is attributed to differences in mode of operation rather than to the difference in feed. The gas composition in the reactor bed is thermodynamically unfavorable for oxidation of the ferrous sulfide except at regions near the oxygen inlet. The ferrous sulfide oxidation and ash agglomeration achieved with washed coal are attributed to the introduction of a greater portion of the oxygen into the venturi area than in previous tests.

  15. Impact of coal fly ash addition on ash transformation and deposition in a full-scale wood suspension-firing boiler

    DEFF Research Database (Denmark)

    Wu, Hao; Bashir, Muhammad Shafique; Jensen, Peter Arendt;

    2013-01-01

    Ash transformation and deposition during pulverized wood combustion in a full-scale power plant boiler of 800 MWth were studied with and without the addition of coal fly ash. The transient ash deposition behavior was characterized by using an advanced deposit probe system at two boiler locations...... constant after a few hours. The formed deposits, especially those at the location with low flue gas temperatures, contained a considerable amount of K2SO4, KCl, and KOH/K2CO3. With the addition of a large amount (about 4 times of the mass flow of wood ash) of coal fly ash to the boiler, these alkali...

  16. Pulverized glass as an alternative filter medium

    Energy Technology Data Exchange (ETDEWEB)

    Piccirillo, J.B.; Letterman, R.D.

    1998-07-01

    A significant amount of low-value, recycled glass is stockpiled at recycling facilities or landfilled. This study was conducted to investigate the use of pulverized recycled glass as a filter medium in slow sand filtration. The glass was pulverized using a flail mill-type pulverizer. The size distribution of the pulverizer output was adjusted by sieving to meet the grain size requirements of the Ten States Standards and the USEPA for filter media were compared to a fourth unit containing silica sand media. The filter influent was spiked with clay, coliform group bacteria and the cysts and oocyst of Giardia lamblia and Cryptosporidium parvum. Over an 8 month period of continuous operation, the performance of the glass sand filter media was as good as or better than the silica sand, with removals of 56% to 96% for turbidity; 99.78% to 100.0% for coliform bacteria; 99.995% to 99.997% for giardia cysts; and 99.92% to 99.97% for cryptosporidium oocysts. According to a cost-benefit analysis, converting waste glass into filter media may be economically advantageous for recycling facilities.

  17. X-ray powder diffraction-based method for the determination of the glass content and mineralogy of coal (co)-combustion fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    O. Font; N. Moreno; X. Querol; M. Izquierdo; E. Alvarez; S. Diez; J. Elvira; D. Antenucci; H. Nugteren; F. Plana; A. Lopez; P. Coca; F.G. Pena [Institute of Environmental Assessment and Water Research (IDA-CSIC), Barcelona (Spain)

    2010-10-15

    The relevance of Al-Si glass in a number of fly ash applications, such as use as a pozzolanic material, zeolite synthesis, and geopolymer production, necessitated research towards investigation of methods for an easy and consistent determination of the glass content in this coal (co)-combustion by-products. A glass standard-addition X-ray powder diffraction (XRD)-based method is proposed in this study as an alternative to the non straightforward procedure of conventional methods for determining the amorphous components, mainly by difference of the total mass and the addition of quantified crystalline species. A >99% Al-Si glass slag sample was selected as a standard for glass. A number of glass standard/fly ash mixtures were performed on Fluidized Bed Combustion (FBC) and pulverized coal combustion (PCC) fly ashes and subsequently analyzed by XRD. The method provides results closer to quantitative proportions of the Al-Si amorphous material of this (co)-combustion by-product, with a range of values <3% when compared with those obtained by the conventional Reference Intensity Method (RIM) method, demonstrating suitability and consistence of the procedure. The mineralogy of FBC and PCC fly ash was also investigated using the RIM method. The occurrence and proportions of the crystalline components in fly ash are in line with the combustion technology and their inherent operational parameters, especially the (co)-combustion temperature. The FBC fly ash shows the highest content of relic phases from feed coal (quartz, illite, calcite, and feldspars) and lower contents of amorphous components. The PCC fly ash are characterized by the highest proportions of mullite and Al-Si glass and low contents of quartz an other relict phases. The occurrence and distribution of anhydrite and Fe-oxide species appears to be related to the content of Ca and Fe in the feed fuels, showing slightly higher contents in FBC than in PCC fly ash. 26 refs., 3 figs., 5 tabs.

  18. Mercury speciation and its emissions from a 220 MW pulverized coal-fired boiler power plant in flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.H.; Zhuo, Y.Q.; Duan, Y.F.; Chen, L.; Yang, L.G.; Zhang, L.A.; Jiang, Y.M.; Xu, X.C. [Southeast University, Nanjing (China). Thermoenergy Engineering Research Institute

    2007-07-15

    Distributions of mercury speciation of Hg{sup 0}, Hg{sup 2+} and Hg{sup P} in flue gas and fly ash were sampled by using the Ontario Hydro Method in a 220 MW pulverized coal-fired boiler power plant in China. The mercury speciation was varied greatly when flue gas going through the electrostatic precipitator (ESP). The mercury adsorbed on fly ashes was found strongly dependent on unburnt carbon content in fly ash and slightly on the particle sizes, which implies that the physical and chemical features of some elemental substances enriched to fly ash surface also have a non-ignored effect on the mercury adsorption. The concentration of chlorine in coal, oxygen and NOx in flue gas has a positive correlation with the formation of the oxidized mercury, but the sulfur in coal has a positive influence on the formation of elemental mercury.

  19. Modeling of pulverized coal combustion stabilization by means of plasma torches

    Energy Technology Data Exchange (ETDEWEB)

    Miroslav Sijercic; Srdjan Belosevic; Predrag Stefanovic [VINCA Institute of Nuclear Science, Belgrade (Serbia and Montenegro)

    2005-07-01

    Application of plasma-system for pulverized coal ignition and combustion stabilization in utility boiler furnaces promises to achieve certain savings compared to the use of heavy oil burners. Plasma torches are built in air-coal dust mixture ducts between coal mills and burners. Characteristics of processes in the ducts with plasma-system for pulverized coal combustion stabilization are analyzed in the paper, with respect to the modeling and numerical simulation of mass, momentum and heat transfer in two-phase turbulent gas particle flow. The simulations have been performed for three different geometries of the air-coal dust mixture ducts with plasma torches, for TENT A1 utility boiler and pulverized lignite Kolubara-Field 'D'. Selected results of numerical simulation of processes are presented. The plasma-system thermal effect is discussed regarding corresponding savings of liquid fuel. The results of numerical simulations have been analyzed with respect to the processes in the duct and especially with respect to the influence of the duct shape to a temperature field at the out let cross section, as a basis for the duct geometry optimization. It has been emphasized that numerical simulation of processes can be applied in analysis and optimization of pulverized coal ignition and combustion stabilization and enables efficient and cost-effective scaling-up procedure from laboratory to industrial level. 22 refs., 4 figs.

  20. Characterization of fly ash from bio and municipal waste

    DEFF Research Database (Denmark)

    Lima, Ana T.; Ottosen, Lisbeth M.; Pedersen, Anne Juul

    2008-01-01

    Four different fly ashes are characterized in the present paper. The ashes differ in the original fuel type and were sampled at distinct plants. The investigation includes two different ashes from municipal solid waste incineration (with and without sorbents addition), a straw ash and an ash from...... potentiality to be valorized. The main conclusion of this paper regards fly ash’s profound dissimilarity, where each ash should be studied separately....

  1. Post-treatment of Fly Ash by Ozone in a Fixed Bed Reactor

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard; Melia, M. C.; Jensen, Anker Degn

    2009-01-01

    The residual carbon in fly ash produced from pulverized coal combustion can adsorb the air-entraining admixtures (AEAs) added to enhance air entrainment in concrete. This behavior of the ash can be suppressed by exposing the fly ash to oxidizing species, which oxidizes the carbon surface and thus...... prevents the AEA to be adsorbed. In the present work, two fly ashes have been ozonated in a fixed bed reactor and the results showed that ozonation is a potential post-treatment method that can lower the AEA requirements of a fly ash up to 6 times. The kinetics of the carbon oxidation by ozone was found...

  2. Fly ash-reinforced thermoplastic starch composites

    Energy Technology Data Exchange (ETDEWEB)

    Ma, X.F.; Yu, J.G.; Wang, N. [Tianjin University, Tianjin (China). School of Science

    2007-01-02

    As a by-product from the combustion of pulverized coal, fly ash was, respectively, used as the reinforcement for formamide and urea-plasticized thermoplastic starch (FUPTPS) and glycerol-plasticized thermoplastic starch (GPTPS). The introduction of fly ash improved tensile stress from 4.56 MPa to 7.78 MPa and Youngs modulus increased trebly from 26.8 MPa to 84.6 MPa for fly ash-reinforced FUPTPS (A-FUPTPS), while tensile stress increased from 4.55 MPa to 12.86 MPa and Youngs modulus increased six times from 76.4 MPa to 545 MPa for fly ash-reinforced GPTPS (A-GPTPS). X-ray diffractograms illustrated that fly ash destroyed the formation of starch ordered crystal structure, so both A-GPTPS and FUPTPS could resist the starch re-crystallization (retrogradation). Also fly ash improved water resistance of TPS. As shown by rheology, during the thermoplastic processing, the extruder screw speed effectively adjusted the flow behavior of A-FUPTPS, while the increasing of the processing temperature effectively ameliorated the flow behavior of A-GPTPS. However, superfluous ash contents (e.g., 20 wt%) worsened processing fluidity and resulted in the congregation of fly ash in FUPTPS matrix (tested by SEM) rather than in GPTPS matrix. This congregation decreased the mechanical properties and water resistance of the materials.

  3. Comparative studies on fly ash coated low heat rejection diesel engine on performance and emission characteristics fueled by rice bran and pongamia methyl ester and their blend with diesel

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed Musthafa, M.; Sivapirakasam, S.P.; Udayakumar, M. [National Institute of Technology, Tiruchchirappalli (India)

    2011-05-15

    In this study, for the first time, fly ash was used as a thermal barrier coating material in a diesel engine. The study consists of three phases. In first phase, biodiesel was prepared in a laboratory scale setup by single step base catalyzed transesterification method. In the second phase, engine combustion chamber elements such as cylinder head, cylinder liner, valves and piston crown face were coated with fly ash, which is a thermal power plant waste, to a thickness of 200{mu}m by using plasma spray coating method. In third phase, experiments were carried out on fly ash coated single cylinder diesel engine fueled by methyl ester of rice bran, pongamia oil and its blend (20% by volume) with diesel. The test run was repeated on uncoated engine under the same running conditions and the results were compared. An increase in engine power and decrease in specific fuel consumption, as well as significant improvements in exhaust gas emissions (except NOx) were observed for all test fuels used in the fly ash coated engine compared with that of the uncoated engine.

  4. Ash Management Review—Applications of Biomass Bottom Ash

    Directory of Open Access Journals (Sweden)

    Harpuneet S. Ghuman

    2012-10-01

    Full Text Available In industrialized countries, it is expected that the future generation of bioenergy will be from the direct combustion of residues and wastes obtained from biomass. Bioenergy production using woody biomass is a fast developing application since this fuel source is considered to be carbon neutral. The harnessing of bioenergy from these sources produces residue in the form of ash. As the demand for bioenergy production increases, ash and residue volumes will increase. Major challenges will arise relating to the efficient management of these byproducts. The primary concerns for ash are its storage, disposal, use and the presence of unburned carbon. The continual increase in ash volume will result in decreased ash storage facilities (in cases of limited room for landfill expansion, as well as increased handling, transporting and spreading costs. The utilization of ash has been the focus of many studies, hence this review investigates the likely environmental and technological challenges that increased ash generation may cause. The presence of alkali metals, alkaline earth metals, chlorine, sulphur and silicon influences the reactivity and leaching to the inorganic phases which may have significant impacts on soils and the recycling of soil nutrient. Discussed are some of the existing technologies for the processing of ash. Unburned carbon present in ash allows for the exploration of using ash as a fuel. The paper proposes sieve fractionation as a suitable method for the separation of unburnt carbon present in bottom ash obtained from a fixed-bed combustion system, followed by the application of the gasification technology to particle sizes of energy importance. It is hoped that this process will significantly reduce the volume of ash disposed at landfills.

  5. Biomass fly ash in concrete: SEM, EDX and ESEM analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shuangzhen Wang; Larry Baxter; Fernando Fonseca [Brigham Young University, Provo, UT (USA). Department of Chemical Engineering

    2008-03-15

    This document summarizes microscopy study of concrete prepared from cement and fly ash (25% fly ash and 75% cement by weight), which covers coal fly ash and biomass fly ash. All the fly ash concrete has the statistical equal strength from one day to one year after mix. Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) and environmental scanning electron microscopy (ESEM) analysis show that both coal and biomass fly ash particles undergo significant changes of morphology and chemical compositions in concrete due to pozzolanic reaction, although biomass fly ash differs substantially from coal fly ash in its fuel resources. 8 refs., 17 figs., 1 tab.

  6. Uptake of Cd, Cu, Ni and Zn by the water hyacinth, Eichhornia crassipes (mart.) solms from pulverised fuel ash (PFA) leachates and slurries

    Energy Technology Data Exchange (ETDEWEB)

    Cordes, K.B.; Mehra, A.; Farago, M.E.; Banerjee, D.K. [University of Derby, Derby (United Kingdom). School of Environmental and Applied Science

    2000-12-01

    The main solid waste product from coal-fired power stations is pulverised fuel ash (PFA). This study investigates the uptake of Cd, Cu, Ni and Zn by the aquatic plant E-crassipes grown in leachates and slurries prepared from two different PFA samples. PFA samples were obtained from Indraprastha Power Station (IPP stn.) in New Delhi, India and the Ratcliffe-on-Soar Power Station in the UK. Results show that E. crassipes has a high accumulation capacity for Cd, Cu, Ni and Zn from leachates and slurries generated from two different PFAs and uptake of these metals is stronger in the roots than in the tops of the plant. As the metal concentrations in the growth medium increase in the 1:5 PFA:DIW ratio as compared to the 1:50 ratio, metal accumulation (as indicated by accumulation factor (AF) values) from both leachates and slurries is higher for plants grown in the 1:50 (PFA:DIW) ratios than in the 1:5 ratios. Lower metal accumulation in the plants grown in slurries than in leachates is related to the high turbidity of growth medium in slurries resulting in ash particles adhering to the root surfaces thus reducing the surface area of metal absorption. In terms of neutralisation capacity of the pH of the growth medium, Eichhornia is seen to be able to reduce the pH of all leachates. Accumulation of Cd and Zn by the plant is higher from the lower pH IPP leachates than the Ratcliffe leachates, indicating that these metals are more soluble and bioavailable in the acidic medium. Accumulation of Cu and Ni is independent of the pH of the leachates; indicating that there may be other contributory factors. 78 refs., 7 tabs.

  7. Combustion characterization of beneficiated coal-based fuels. Quarterly report No. 15, October--December 1992

    Energy Technology Data Exchange (ETDEWEB)

    Chow, O.K.; Nsakala, N.Y.

    1993-03-01

    The Pittsburgh Energy Technology Center of the US Department of Energy has contracted with Combustion Engineering, Inc. (CE) to perform a five-year project on ``Combustion Characterization of Beneficiated Coal-Based Fuels.`` The beneficiated coals are produced by other contractors under the DOE Coal Preparation Program. Several contractor-developed advanced coal cleaning processes are run at pilot-scale cleaning facilities to produce 20-ton batches of fuels for shipment to CE`s laboratory in Windsor, Connecticut. CE then processes the products into either a coal-water fuel (CWF) or a dry microfine pulverized coa1 (DMPC) form for combustion testing. The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of BCFs influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. The technical approach used to develop the technical data includes: bench-scale fuel property, combustion, and ash deposition tests; pilot-scale combustion and ash effects tests; and full-scale combustion tests. During the third quarter of 1992, the following technical progress was made: Continued analyses of drop tube furnace samples to determine devolatilization kinetics; re-analyzed the samples from the pilot-scale ash deposition tests of the first nine feed coals and BCFs using a modified CCSEM technique; updated the topical summary report; and prepared for upcoming tests of new BCFs being produced.

  8. Pulverized coal injection at BF N5 during campaign extension period : ArcelorMittal South Africa, Newcastle Works

    Energy Technology Data Exchange (ETDEWEB)

    Scholtz, V. [ArcelorMittal South Africa, Newcastle, KwaZulu-Natal (South Africa)

    2008-07-01

    Blast furnace no. 5 at ArcelorMittal South Africa's Newcastle facility was constructed in 1976 and designed to produce 5000 thm/day, with a hearth diameter of 10.14 m and a working volume of 2017 m{sup 3}. In April 2005, it began using pulverized coal (PC) following a planned maintenance shutdown. Initially, the PC was injected at a rate of 70 kg/thm, but within 5 months, the PC injection (PCI) rate was increased to 160 kg/thm. This was achieved with good replacement ratios, despite a burden that consisted of 40 per cent lump ore. However, the success was brief because of the high rate of unprepared burden, inadequate raw material quality and an aging hearth. The coke rate was therefore increased to reduce hearth wear while maintaining decent hot metal production, resulting in a lower than expected PCI rate of 100 kg/thm. The injection coal rate of 160 kg/thm will be targeted again once the hearth is replaced. Very few changes had been made in the PCI blend in the past because of the low-cost local supply of high volatile, medium ash coals. However, a new coal mine that opened in Newcastle in July 2007 made it possible to partially replace the coal in use. This paper described the operating parameters for the campaign extension period, which required a less than standard injection practice to reduce the amount of production outages. The hearth and stave conditions during the campaign extension were found to be the major barriers to injecting high PCI rates. It was concluded that it is important to re-evaluate the raw material cost for all the fuels used on a regular basis, since the costs to produce coke for higher injection rates could outweigh the advantages at the blast furnace. 3 refs., 1 tabs., 3 figs.

  9. Ash partitioning during the oxy-fuel combustion of lignite and its dependence on the recirculation of flue gas impurities (H{sub 2}O, HCl and SO{sub 2})

    Energy Technology Data Exchange (ETDEWEB)

    Facun Jiao; Juan Chen; Lian Zhang; Yajuan Wei; Yoshihiko Ninomiya; Sankar Bhattacharya; Hong Yao [Monash University, Clayton, Vic. (Australia). Department of Chemical Engineering

    2011-06-15

    Oxy-fuel combustion of a brown coal (i.e. lignite) has been carried out at 1000{sup o}C to experimentally examine the vaporisation of organically bound metals and the agglomeration of ash particles as a function of the concentration of gaseous impurities including H{sub 2}O, HCl and SO{sub 2} in about 27% O{sub 2} balanced with CO{sub 2}. The properties of bulk ash and individual metals were investigated intensively. Particularly, attention was paid to Na which is notorious for fouling and to organically bound Al which has been less studied. The results indicate that, the organically bound metals, although possessing a very low content in the raw coal, are vital for the agglomeration of ash particles, which are also highly sensitive to the loading of gas impurities in flue gas. HCl recirculation is the most crucial factor promoting the vaporisation of metals via chlorination. Apart from alkali metals, the organically bound Al and Ti were also vaporised noticeably. Recirculation of SO{sub 2} promoted the sulfation of Na to condense into liquid droplet which increased fine ash yield. Co-existence of bulk HCl and SO{sub 2} played a synergetic role in the sulfation of Na via an initial chlorination of the char-bound Na. In contrast, co-existence of steam with HCl and SO{sub 2} favored the formation of Na alumino-silicates, which are favorable for ash agglomeration. 34 refs., 15 figs., 3 tabs.

  10. Corrosion of high temperature resisting alloys exposed to heavy fuel ash; Corrosion de aleaciones resistentes a altas temperaturas expuestas a ceniza de combustoleo pesado

    Energy Technology Data Exchange (ETDEWEB)

    Wong Moreno, Adriana del Carmen

    1998-03-01

    The objective of the performed research was to study the degradation process by high temperature corrosion of alloys exposed to heavy fuel oil ashes through a comparative experimental evaluation of its performance that allowed to establish the mechanisms involved in the phenomenon. The experimentation carried out involved the determination of the resistance to the corrosion of 14 alloys of different type (low and medium alloy steels, ferritic and austenitic stainless steels, nickel base alloys and a FeCrAl alloy of type ODS) exposed to high temperatures (580 Celsius degrees - 900 Celsius degrees) in 15 ash deposits with different corrosive potential, which were collected in the high temperature zone of boilers of thermoelectric power stations. The later studies to the corrosion tests consisted of the analysis by sweeping electron microscopy supported by microanalysis of the corroded probes, with the purpose of determining the effect of Na, V and S on the corrosivity of the ash deposits and the effect of the main alloying elements on the corrosion resistance of the alloys. Such effects are widely documented to support the proposed mechanisms of degradation that are occurring. The global analysis of the generated results has allowed to propose a model to explain the global mechanism of corrosion of alloys exposed to the high temperatures of ash deposits. The proposed model, complements the processed one by Wilson, widely accepted for fused vanadates, as far as on one hand, it considers the effect of the sodium sulfate presence (in addition to the vanadium compounds) in the deposits, and on the other hand, it extends it to temperatures higher than the point of fusion of constituent vanadium compounds of the deposits. Both aspects involve considering the roll that the process of diffusion of species has on the degradation and the capacity of protection of the alloy. The research performed allowed to confirm what the Wilson model had established for deposits with high

  11. Modeling calcium dissolution from oil shale ash: Part 2.. Continuous washing of the ash layer

    Energy Technology Data Exchange (ETDEWEB)

    Velts, O.; Kallas, J. [Tallinn University of Technology, Laboratory of Inorganic Materials, 5 Ehitajate Str., Tallinn 19086 (Estonia); Lappeenranta University of Technology, Laboratory of Separation Technology, Skinnarilankatu 34, Lappeenranta 53851 (Finland); Hautaniemi, M.; Kuosa, M. [Lappeenranta University of Technology, Laboratory of Separation Technology, Skinnarilankatu 34, Lappeenranta 53851 (Finland); Kuusik, R. [Tallinn University of Technology, Laboratory of Inorganic Materials, 5 Ehitajate Str., Tallinn 19086 (Estonia)

    2010-05-15

    In the present work a possible approach to the utilization of oil shale ash containing free lime in precipitated calcium carbonate (PCC) production is elucidated. This paper investigates the Ca (calcium) dissolution process during continuous washing of pulverized firing (PF) and fluidized bed combustion (FBC) oil shale ash layers in a packed-bed leaching column. The main characteristics of the Ca dissolution process from ash are established. The effect of water flow rate is investigated by conducting leaching experiments of oil shale ashes formed in boilers operating with different combustion technologies. The values of the overall and liquid phase mass transfer coefficients are evaluated based on experiments using the developed ash layer washing model. The model is a set of partial differential equations that describe the changes in Ca content in the stagnant layer of ash and in the water flowing through the ash layer. An example in which the model is applied to environmental assessment and estimation of Ca leaching from industrial oil shale ash fields is provided. (author)

  12. Combustion characterization of beneficiated coal-based fuels. Quarterly report No. 8, January--March 1991

    Energy Technology Data Exchange (ETDEWEB)

    Chow, O.K.; Nsakala, N.Y.

    1991-07-01

    The Pittsburgh Energy Technology Center of the US Department of Energy has contracted with Combustion Engineering, Inc. (CE) to perform a five-year project on ``Combustion Characterization of Beneficiated Coal-Based Fuels.`` The beneficiated coals are produced by other contractors under the DOE Coal Preparation Program. Several contractor-developed advanced coal cleaning processes are run at pilot-scale cleaning facilities to produce 20-ton batches of fuels for shipment to CE`s laboratory in Windsor, Connecticut. CE then processes the products into either a coal-water fuel (CWF) or a dry microfine pulverized coa1 (DMPC) form for combustion testing. The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of BCFs influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. During the third quarter of 1991, the following technical progress was made: Calculated the kinetic characteristics of chars from the combustion of spherical oil agglomeration beneficiated products; continued drop tube devolatilization tests of the spherical oil agglomeration beneficiated products; continued analyses of the data and samples from the CE pilot-scale tests of nine fuels; and started writing a summary topical report to include all results on the nine fuels tested.

  13. Nano-pulverization of poorly water soluble compounds with low melting points by a rotation/revolution pulverizer.

    Science.gov (United States)

    Yuminoki, K; Takeda, M; Kitamura, K; Numata, S; Kimura, K; Takatsuka, T; Hashimoto, N

    2012-08-01

    We report a method for pulverizing poorly water soluble compounds with low melting points to nanoparticles without producing an amorphous phase using a rotation/revolution pulverizer. Fenofibrate, flurbiprofen, and probucol were used as crystalline model compounds. They were suspended in a methylcellulose aqueous solution and pulverized with zirconia balls by the rotation/revolution pulverizer. Beeswax, an amorphous compound, was also examined to investigate whether nano-pulverization of a compound with a low melting point was possible. Beeswax was suspended in ethyl alcohol cooled with liquid nitrogen and pulverized with zirconia balls by the rotation/revolution pulverizer. By optimizing the pulverization parameters, nanoparticles (D50 revolution speed of 1000 rpm and a rotation/revolution ratio of 1.0 when the vessel was 0 degrees C. Amorphous fenofibrate and flurbiprofen were not detected by differential scanning calorimetry or powder X-ray diffraction, whereas small amounts of amorphous probucol were detected. Beeswax was pulverized to nanoparticles (D50 = 0.14 microm) with ethyl alcohol cooled with liquid nitrogen. Fine nanoparticles of these poorly water soluble compounds with low melting points were obtained by controlling the rotation/revolution speed and reducing the vessel temperature.

  14. Energy Analysis of a Biomass Co-firing Based Pulverized Coal Power Generation System

    Directory of Open Access Journals (Sweden)

    Marc A. Rosen

    2012-03-01

    Full Text Available The results are reported of an energy analysis of a biomass/coal co-firing based power generation system, carried out to investigate the impacts of biomass co-firing on system performance. The power generation system is a typical pulverized coal-fired steam cycle unit, in which four biomass fuels (rice husk, pine sawdust, chicken litter, and refuse derived fuel and two coals (bituminous coal and lignite are considered. Key system performance parameters are evaluated for various fuel combinations and co-firing ratios, using a system model and numerical simulation. The results indicate that plant energy efficiency decreases with increase of biomass proportion in the fuel mixture, and that the extent of the decrease depends on specific properties of the coal and biomass types.

  15. Pretreatment of biomass by torrefaction and carbonization for coal blend used in pulverized coal injection.

    Science.gov (United States)

    Du, Shan-Wen; Chen, Wei-Hsin; Lucas, John A

    2014-06-01

    To evaluate the utility potential of pretreated biomass in blast furnaces, the fuel properties, including fuel ratio, ignition temperature, and burnout, of bamboo, oil palm, rice husk, sugarcane bagasse, and Madagascar almond undergoing torrefaction and carbonization in a rotary furnace are analyzed and compared to those of a high-volatile coal and a low-volatile one used in pulverized coal injection (PCI). The energy densities of bamboo and Madagascar almond are improved drastically from carbonization, whereas the increase in the calorific value of rice husk from the pretreatment is not obvious. Intensifying pretreatment extent significantly increases the fuel ratio and ignition temperature of biomass, but decreases burnout. The fuel properties of pretreated biomass materials are superior to those of the low-volatile coal. For biomass torrefied at 300°C or carbonized at temperatures below 500°C, the pretreated biomass can be blended with coals for PCI.

  16. Semi-wet selective pulverizing system: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Ito, K.; Hirayama, Y.

    1975-05-01

    The operation of the semi-wet selective pulverizing system for recovering materials from municipal waste is described. In this system both pulverization and classification of materials is accomplished in one machine. This process can be used to recover paper, plastics, metals, and compostable materials. (LCL)

  17. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy

    2005-10-01

    Low rank fuels such as subbituminous coals and lignites contain significant amounts of moisture compared to higher rank coals. Typically, the moisture content of subbituminous coals ranges from 15 to 30 percent, while that for lignites is between 25 and 40 percent, where both are expressed on a wet coal basis. High fuel moisture has several adverse impacts on the operation of a pulverized coal generating unit. High fuel moisture results in fuel handling problems, and it affects heat rate, mass rate (tonnage) of emissions, and the consumption of water needed for evaporative cooling. This project deals with lignite and subbituminous coal-fired pulverized coal power plants, which are cooled by evaporative cooling towers. In particular, the project involves use of power plant waste heat to partially dry the coal before it is fed to the pulverizers. Done in a proper way, coal drying will reduce cooling tower makeup water requirements and also provide heat rate and emissions benefits. The technology addressed in this project makes use of the hot circulating cooling water leaving the condenser to heat the air used for drying the coal (Figure 1). The temperature of the circulating water leaving the condenser is usually about 49 C (120 F), and this can be used to produce an air stream at approximately 43 C (110 F). Figure 2 shows a variation of this approach, in which coal drying would be accomplished by both warm air, passing through the dryer, and a flow of hot circulating cooling water, passing through a heat exchanger located in the dryer. Higher temperature drying can be accomplished if hot flue gas from the boiler or extracted steam from the turbine cycle is used to supplement the thermal energy obtained from the circulating cooling water. Various options such as these are being examined in this investigation. This is the eleventh Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits

  18. Upgraded fuel from reed canary grass

    Energy Technology Data Exchange (ETDEWEB)

    Heiskanen, V.P.

    1995-12-31

    The feasibility of RCG for commercial utilization depends primarily on its applicability for pulp production and its use in energy production will be based on the residue that will be available after extracting the pulp fraction of the RCG. Roughly 20 ..30% of the material will be available for energy production purposes. However, the percentage may be higher/lower depending on the quality standards of the pulp fiber material. The harvesting period has a significant effect on the fuel characteristics of RCG. For instance the contents of N, S, Cl, K are clearly lower if the RCG is harvested in the spring (delayed) instead of summer/autumn. These elements affect significantly overall emission formation and ash behaviour and its melting temperature. The combustion related research in this project has been focused on the spring-harvested RCG. The project aims to evaluate the feasibility of delayed harvested RCG for energy production. In order to reach this goal, the following combustion methods will be tested and studied: combustion of pelletized RCG; gasification; combustion of pulverized RCG. In addition, pelletizing, reactivity and NO conversion of pulverized RCG will be studied. The research described here is a part of `Reed Canary Grass` project (in AIR programme). The contractors of the project are Swedish University of Agricultural Sciences (coordinator), United Milling Systems from Denmark, Jaakko Poeyry Oy and VTT Energy. In addition, there are partners from several countries participating in the project. The project has been divided in five tasks, VTT Energy being responsible for combustion related task `Upgraded fuel` that includes the research topics discussed in this paper

  19. Detailed model for practical pulverized coal furnaces and gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Philips, S.D.; Smoot, L.D.

    1989-08-01

    The need to improve efficiency and reduce pollutant emissions commercial furnaces has prompted energy companies to search for optimized operating conditions and improved designs in their fossil-fuel burning facilities. Historically, companies have relied on the use of empirical correlations and pilot-plant data to make decisions about operating conditions and design changes. The high cost of collecting data makes obtaining large amounts of data infeasible. The main objective of the data book is to provide a single source of detailed three-dimensional combustion and combustion-related data suitable for comprehensive combustion model evaluation. Five tasks were identified as requirements to achieve the main objective. First, identify the types of data needed to evaluate comprehensive combustion models, and establish criteria for selecting the data. Second, identify and document available three-dimensional combustion data related to pulverized coal combustion. Third, collect and evaluate three-dimensional data cases, and select suitable cases based on selection criteria. Fourth, organize the data sets into an easy-to-use format. Fifth, evaluate and interpret the nature and quality of the data base. 39 refs., 15 figs., 14 tabs.

  20. Experimental study on preheated combustion of pulverized semi-coke

    Science.gov (United States)

    Yao, Yao; Zhu, Jianguo; Lu, Qinggang; Zhou, Zuxu

    2015-06-01

    In a test rig, pulverized semi-coke was preheated to 850oC in a circulating fluidized bed (CFB) and then combusted at 1100oC in a down-fired combustor (DFC). Experiments were conducted to reveal the effects of three secondary air nozzle cases (co-axial jet, top circular jet and wall circular jet) on the NO emission. The results show that the optimized secondary air nozzle can reduce NO emission. O2 concentration profile is the major factor affecting NO generation and emission, which is led by the secondary air nozzle. The lower O2 concentration led to the generation of lower initial NO. The NO emission at the exit of the DFC was reduced from 189 to 92 mg/m3 (@ 6% O2) with the decrease of initial generation. The peak of NO at 100 mm below the nozzle should be attributed to the oxidization of NH3 in the syngas, rather than the oxidization of fuel-N in the char. The low and well-distributed O2 concentration contributes to the reduction of initial NO, which helps to reduce the NO emission. The combustion efficiencies of the cases of the co-axial jet, the top circular jet, and the wall circular jet are 97.88%, 98.94% and 98.74%, respectively.

  1. Soot, organics, and ultrafine ash from air- and oxy-fired coal combustion

    Science.gov (United States)

    This paper/presentation is concerned with determining the effects of oxy-combustion of coal on the composition of the ultrafine fly ash. To this end, a 10 W externally heated entrained flow furnace was modified to allow the combustion of pulverized coal in flames under practicall...

  2. Soot, organics and ultrafine ash from air- and oxy-fired coal combustion

    Science.gov (United States)

    This paper is concerned with determining the effects of oxy-combustion of coal on the composition of the ultrafine fly ash. To this end, a 10 W externally heated entrained flow furnace was modified to allow the combustion of pulverized coal in flames under practically relevant s...

  3. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy; Harun Bilirgen; Ursla Levy; John Sale; Nenad Sarunac

    2006-01-01

    This is the twelfth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture using power plant waste heat, prior to firing the coal in a pulverized coal boiler. During this last Quarter, the development of analyses to determine the costs and financial benefits of coal drying was continued. The details of the model and key assumptions being used in the economic evaluation are described in this report and results are shown for a drying system utilizing a combination of waste heat from the condenser and thermal energy extracted from boiler flue gas.

  4. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy; Harun Bilirgen; Ursla Levy; John Sale; Nenad Sarunac

    2006-01-01

    This is the twelfth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture using power plant waste heat, prior to firing the coal in a pulverized coal boiler. During this last Quarter, the development of analyses to determine the costs and financial benefits of coal drying was continued. The details of the model and key assumptions being used in the economic evaluation are described in this report and results are shown for a drying system utilizing a combination of waste heat from the condenser and thermal energy extracted from boiler flue gas.

  5. DETERMINING THE ROLE OF INDIVIDUAL FLY ASH PARTICLES IN INFLUENCING THE VARIATION IN THE OVERALL PHYSICAL, MORPHOLOGICAL, AND CHEMICAL PROPERTIES OF FLY ASH

    Directory of Open Access Journals (Sweden)

    Usman Haider

    2016-08-01

    Full Text Available The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic,where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

  6. Trace element emissions when firing pulverized coal in a pilot-scale combustion facility

    Energy Technology Data Exchange (ETDEWEB)

    Miller, S.F.; Wincek, R.T.; Miller, B.G.; Scaroni, A.W.

    1998-07-01

    Strategies are being developed at Penn State to produce ultralow emissions when firing coal-based fuels, i.e., micronized coal and coal-water slurry fuel (CWSF), in industrial boilers. The work is being conducted on the bench, pilot, and demonstration scale, and the emissions being addressed are SO{sub 2}, NO{sub x}, fine particulate matter (PM{sub 10} and PM{sub 2.5}), and air toxics (trace elements and volatile organic compounds). Technical issues related to trace element emissions that are to be addressed include: (1) the effectiveness of coal cleaning; (2) the effect of fuel form (CWSF and pulverized coal); (3) partitioning between the solid and vapor phases; (4) the effect of boiler size; (5) penetration through particulate control devices; (6) the effect of sootblowing; and (7) mercury speciation. This paper discusses the results of preliminary work to determine trace element emissions when firing a raw and cleaned pulverized coal in a pilot-scale combustor. A companion paper, which follows in the proceedings, gives the results of polynuclear aromatic hydrocarbon (PAH) emissions testing in the pilot-scale combustor and in a small industrial boiler. Results from fine particulate testing is found elsewhere in the proceedings.

  7. Environmental hazard of oil shale combustion fly ash.

    Science.gov (United States)

    Blinova, Irina; Bityukova, Liidia; Kasemets, Kaja; Ivask, Angela; Käkinen, Aleksandr; Kurvet, Imbi; Bondarenko, Olesja; Kanarbik, Liina; Sihtmäe, Mariliis; Aruoja, Villem; Schvede, Hedi; Kahru, Anne

    2012-08-30

    The combined chemical and ecotoxicological characterization of oil shale combustion fly ash was performed. Ash was sampled from the most distant point of the ash-separation systems of the Balti and Eesti Thermal Power Plants in North-Eastern Estonia. The fly ash proved potentially hazardous for tested aquatic organisms and high alkalinity of the leachates (pH>10) is apparently the key factor determining its toxicity. The leachates were not genotoxic in the Ames assay. Also, the analysis showed that despite long-term intensive oil-shale combustion accompanied by considerable fly ash emissions has not led to significant soil contamination by hazardous trace elements in North-Eastern Estonia. Comparative study of the fly ash originating from the 'new' circulating fluidized bed (CFB) combustion technology and the 'old' pulverized-fired (PF) one showed that CFB fly ash was less toxic than PF fly ash. Thus, complete transfer to the 'new' technology will reduce (i) atmospheric emission of hazardous trace elements and (ii) fly ash toxicity to aquatic organisms as compared with the 'old' technology. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Combustion of stoker ash in a CFBC

    Energy Technology Data Exchange (ETDEWEB)

    Jia, L.; Anthony, E.J. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2002-07-01

    The ash generated from petroleum coke fired stokers at Georgia Pacific in Wisconsin has an elevated carbon content and a higher fuel value. This paper presents results of a study in which the stoker ash was test fired at the CANMET Energy Technology Centre in a bench scale circulating fluidized bed combustor (CFBC). The objective was to determine if firing the stoker ash in its 'as received' state (with a 40 per cent moisture content) is a viable fuel option for Georgia Pacific's FBC boiler to save fuel costs, or if it should be co-fired with petroleum coke. Mixtures of the stoker ash and petroleum coke were also test fired. Results indicate that the stoker ash alone cannot sustain combustion. However, good ignition and even bed temperature is possible with premixed coke and 10 per cent less moisture content. Emissions of sulphur dioxides, nitrogen oxides carbon monoxide were the same as for firing petroleum coke alone. In addition, the co-firing of stoker ash and petroleum coke did not negatively affect the tendency to foul, compared to firing coke alone. The amount of ash generated from the FBC boiler was high due to the high ash content. An economic evaluation showed that firing a 20/80 coke/stoker ash mixture can save approximately 22 per cent of the limestone usage compared to coke firing alone, if the Ca/S molar ratio remain the same. 8 refs., 2 tabs., 1 fig.

  9. Ash particle erosion on steam boiler convective section

    Energy Technology Data Exchange (ETDEWEB)

    Meuronen, V.

    1997-12-31

    In this study, equations for the calculation of erosion wear caused by ash particles on convective heat exchanger tubes of steam boilers are presented. A new, three-dimensional test arrangement was used in the testing of the erosion wear of convective heat exchanger tubes of steam boilers. When using the sleeve-method, three different tube materials and three tube constructions could be tested. New results were obtained from the analyses. The main mechanisms of erosion wear phenomena and erosion wear as a function of collision conditions and material properties have been studied. Properties of fossil fuels have also been presented. When burning solid fuels, such as pulverized coal and peat in steam boilers, most of the ash is entrained by the flue gas in the furnace. In bubbling and circulating fluidized bed boilers, particle concentration in the flue gas is high because of bed material entrained in the flue gas. Hard particles, such as sharp edged quartz crystals, cause erosion wear when colliding on convective heat exchanger tubes and on the rear wall of the steam boiler. The most important ways to reduce erosion wear in steam boilers is to keep the velocity of the flue gas moderate and prevent channelling of the ash flow in a certain part of the cross section of the flue gas channel, especially near the back wall. One can do this by constructing the boiler with the following components. Screen plates can be used to make the velocity and ash flow distributions more even at the cross-section of the channel. Shield plates and plate type constructions in superheaters can also be used. Erosion testing was conducted with three types of tube constructions: a one tube row, an in- line tube bank with six tube rows, and a staggered tube bark with six tube rows. Three flow velocities and two particle concentrations were used in the tests, which were carried out at room temperature. Three particle materials were used: quartz, coal ash and peat ash particles. Mass loss

  10. Impact of petrographic properties on the burning behavior of pulverized coal using a drop tube furnace

    Energy Technology Data Exchange (ETDEWEB)

    S. Biswas; N. Choudhury; S. Ghosal; T. Mitra; A. Mukherjee; S.G. Sahu; M. Kumar [Jadavpur University, Dhanbad (India). Central Fuel Research Institute]. sb_cfri@yahoo.co.in

    2007-12-15

    The combustion behavior of three Indian coals of different rank with wide variation in ash content and maceral compositions were studied using a drop tube furnace (DTF). Each coal was pulverized into a specific size (80% below 200 mesh) and fed into the DTF separately. The DTF runs were carried out under identical conditions for all of the coals. The carbon burnout was found out from the chemical analyses of the feed coals and the char samples collected from different ports of the DTF. Char morphology analyses was carried on the burnout residues of the top port. The top port results show better burnout of the lower rank coals which however was not observed in the last port. An attempt has been made to account for this variation in terms of rank and petrographic parameters of the respective coals. 20 refs., 1 fig., 6 tabs.

  11. Temporal and spatial variations in fly ash quality

    Science.gov (United States)

    Hower, J.C.; Trimble, A.S.; Eble, C.F.

    2001-01-01

    Fly ash quality, both as the amount of petrographically distinguishable carbons and in chemistry, varies in both time and space. Temporal variations are a function of a number of variables. Variables can include variations in the coal blend organic petrography, mineralogy, and chemistry; variations in the pulverization of the coal, both as a function of the coal's Hardgrove grindability index and as a function of the maintenance and settings of the pulverizers; and variations in the operating conditions of the boiler, including changes in the pollution control system. Spatial variation, as an instantaneous measure of fly ash characteristics, should not involve changes in the first two sets of variables listed above. Spatial variations are a function of the gas flow within the boiler and ducts, certain flow conditions leading to a tendency for segregation of the less-dense carbons in one portion of the gas stream. Caution must be applied in sampling fly ash. Samples from a single bin, or series of bins, m ay not be representative of the whole fly ash, providing a biased view of the nature of the material. Further, it is generally not possible to be certain about variation until the analysis of the ash is complete. ?? 2001 Elsevier Science B.V. All rights reserved.

  12. Mercury speciation in pulverized fuel co-combustion and gasification

    NARCIS (Netherlands)

    Sable, S.P.

    2007-01-01

    Coal based power generation is a significant source of mercury emissions to the atmosphere and this has attracted huge attention in the past decade. Recently, the concerns regarding global warming and need for new energy resources introduced the concept of cofiring of biomass and waste as secondary

  13. Mercury speciation in pulverized fuel co-combustion and gasification

    NARCIS (Netherlands)

    Sable, S.P.

    2007-01-01

    Coal based power generation is a significant source of mercury emissions to the atmosphere and this has attracted huge attention in the past decade. Recently, the concerns regarding global warming and need for new energy resources introduced the concept of cofiring of biomass and waste as secondary

  14. Numerical modelling of lighting process in pulverized-coal burner of a boiler unit by the low-temperature plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Miloshevich, H.; Rychkov, A.D. [Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation). Inst. of Occupational Technologies

    1999-07-01

    The authors numerically modelled the process of aeromixture ignition in a pulverized-coal burner by a central axysymmetric jet of air that is heated in an electrical are plasma generator up to about 5000 K. The aim was to investigate the process of coal particle ignition in the flow and establish the conditions under which the independent combustion of pulverized coal mixture occurs. The results obtained showed the important role of radiation heat transfer in initiating the combustion process of solid fuel particles. 8 refs., 5 figs.

  15. Total lead (Pb) concentration in oil shale ash samples based on correlation to isotope Pb-210 gamma-spectrometric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Vaasma, T.; Kiisk, M.; Tkaczyk, A.H. [University of Tartu (Estonia); Bitjukova, L. [Tallinn University of Technology (Estonia)

    2014-07-01

    Estonian oil shale consists of organic matter and mineral material and contains various amounts of heavy metals as well as natural radionuclides (from the U-238 and Th-232 series and K-40). Previous research has shown that burning oil shale in the large power plants causes these radionuclides to become enriched in different ash fractions and be partially emitted to the atmosphere via fly ash and flue gases. The activity concentrations (Bq/kg) of these nuclides in different oil shale ash fractions vary significantly. This is influenced by the boiler parameters and combustion conditions - prevailing temperatures, pressure, ash circulating mechanisms, fly ash particle size, chemical composition of ash and coexistence of macro and micro components. As with radionuclides, various heavy metals remain concentrated in the ash fractions and are released to the atmosphere (over 20 tons of Pb per year from Estonian oil shale power plants). Lead is a heavy metal with toxic influence on the nervous system, reproductive system and different organs in human body. Depending on the exposure pathways, lead could pose a long term health hazard. Ash samples are highly heterogeneous and exhibit great variability in composition and particle size. Determining the lead concentration in ash samples by modern methods like inductively coupled plasma mass spectroscopy (ICP-MS), flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectroscopy (GFAAS) and other techniques often requires time consuming, multistage and complex chemical sample preparation. The list of possible methods to use is lengthy, but it is a challenge to choose a suitable one to meet measurement needs and practical considerations. The detection limits, capital costs and maintenance expenses vary between the instruments. This work presents the development of an alternative measurement technique for our oil shale ash samples. Oil shale ash was collected from different boilers using pulverized fuel

  16. Ashes from fluidized bed combustion of residual forest biomass

    NARCIS (Netherlands)

    Cruz, Nuno C.; Rodrigues, Sónia M.; Carvalho, Lina; Duarte, Armando C.; Pereira, Eduarda; Romkens, Paul; Tarelho, Luís A.C.

    2017-01-01

    Although bottom ash (BA) [or mixtures of bottom and fly ash (FA)] from clean biomass fuels is currently used as liming agent, additive for compost, and fertilizer on agricultural and forest soils in certain European countries, in several other countries most of the ashes are currently disposed in la

  17. Temperature, velocity and species profile measurements for reburning in a pulverized, entrained flow, coal combustor

    Energy Technology Data Exchange (ETDEWEB)

    Tree, D.R.

    1999-03-01

    Nitrogen oxide emissions from pulverized coal combustion have been and will continue to be a regulated pollutant for electric utility boilers burning pulverized coal. Full scale combustion models can help in the design of new boilers and boiler retrofits which meet emissions standards, but these models require validation before they can be used with confidence. The objective of this work was to obtain detailed combustion measurements of pulverized coal flames which implement two NO reduction strategies, namely reburning and advanced reburning, to provide data for model validation. The data were also compared to an existing comprehensive pulverized coal combustion model with a reduced mechanism for NO reduction under reburning and advanced reburning conditions. The data were obtained in a 0.2 MW, cylindrical, down-fired, variable swirl, pulverized coal reactor. The reactor had a diameter of 0.76 m and a length of 2.4 m with access ports along the axial length. A Wyodak, sub-bituminous coal was used in all of the measurements. The burner had a centrally located primary fuel and air tube surrounded by heated and variably swirled secondary air. Species of NO, NO{sub x}, CO, CO{sub 2} and O{sub 2} were measured continuously. Aqueous sampling was used to measure HCN and NH{sub 3} at specific reactor locations. Samples were drawn from the reactor using water quenched suction probes. Velocity measurements were obtained using two component laser doppler anemometry in back-scatter mode. Temperature measurements were obtained using a shielded suction pyrometer. A series of six or more radial measurements at six or more axial locations within the reactor provided a map of species, temperature, and velocity measurements. In total, seven reactor maps were obtained. Three maps were obtained at baseline conditions of 0, 0.5 and 1.5 swirl and 10% excess air. Two maps were obtained under reburning conditions of 0.78 stoichiometric ratio and 1.5 swirl and 0.9 stoichiometric ratio and

  18. Radioactivity of wood ash; Puun tuhkan radioaktiivisuus

    Energy Technology Data Exchange (ETDEWEB)

    Rantavaara, A.; Moring, M

    2000-01-01

    STUK (Finnish Radiation and Nuclear Safety Authority) has investigated natural and artificial radioactivity in wood ash and radiation exposure from radionuclides in ash since 1996. The aim was to consider both handling of ash and different ways of using ash. In all 87 ash samples were collected from 22 plants using entirely or partially wood for their energy production in 1996-1997. The sites studied represented mostly chemical forest industry, sawmills or district heat production. Most plants used fluidised bed combustion technique. Samples of both fly ash and bottom ash were studied. The activity concentrations of radionuclides in samples of, e.g., dried fly ash from fuel containing more than 80% wood were determined. The means ranged from 2000 to less than 50 Bq kg{sup -1}, in decreasing order: {sup 137}Cs, {sup 40}K, {sup 90}Sr, {sup 210}Pb,{sup 226}Ra, {sup 232}Th, {sup 134}Cs, {sup 235}U. In bott radionuclide contents decreased in the same order as in fly ash, but were smaller, and {sup 210}Pb was hardly detectable. The NH{sub 4}Ac extractable fractions of activities for isotopes of alkaline elements (K, Cs) in bottom ash were lower than in fly ash, whereas solubility of heavier isotopes was low. Safety requirements defined by STUK in ST-guide 12.2 for handling of peat ash were fulfilled at each of the sites. Use of ash for land-filling and construction of streets was minimal during the sampling period. Increasing this type of ash use had often needed further investigations, as description of the use of additional materials that attenuate radiation. Fertilisation of forests with wood ash adds slightly to the external irradiation in forests, but will mostly decrease doses received through use of timber, berries, mushrooms and game meat. (orig.)

  19. Radioactivity of wood ash; Puun tuhkan radioaktiivisuus

    Energy Technology Data Exchange (ETDEWEB)

    Rantavaara, A.; Moring, M

    2000-01-01

    STUK (Finnish Radiation and Nuclear Safety Authority) has investigated natural and artificial radioactivity in wood ash and radiation exposure from radionuclides in ash since 1996. The aim was to consider both handling of ash and different ways of using ash. In all 87 ash samples were collected from 22 plants using entirely or partially wood for their energy production in 1996-1997. The sites studied represented mostly chemical forest industry, sawmills or district heat production. Most plants used fluidised bed combustion technique. Samples of both fly ash and bottom ash were studied. The activity concentrations of radionuclides in samples of, e.g., dried fly ash from fuel containing more than 80% wood were determined. The means ranged from 2000 to less than 50 Bq kg{sup -1}, in decreasing order: {sup 137}Cs, {sup 40}K, {sup 90}Sr, {sup 210}Pb,{sup 226}Ra, {sup 232}Th, {sup 134}Cs, {sup 235}U. In bott radionuclide contents decreased in the same order as in fly ash, but were smaller, and {sup 210}Pb was hardly detectable. The NH{sub 4}Ac extractable fractions of activities for isotopes of alkaline elements (K, Cs) in bottom ash were lower than in fly ash, whereas solubility of heavier isotopes was low. Safety requirements defined by STUK in ST-guide 12.2 for handling of peat ash were fulfilled at each of the sites. Use of ash for land-filling and construction of streets was minimal during the sampling period. Increasing this type of ash use had often needed further investigations, as description of the use of additional materials that attenuate radiation. Fertilisation of forests with wood ash adds slightly to the external irradiation in forests, but will mostly decrease doses received through use of timber, berries, mushrooms and game meat. (orig.)

  20. Comparative Techno-economic assessment of biomass and coal with CCS technologies in a pulverized combustion power plant in the United Kingdom

    OpenAIRE

    Al-Qayim, K.; Nimmo, W.; Pourkashanian, M

    2015-01-01

    The technical performance and cost effectiveness of white wood pellets (WWP) combustion in comparison to three types of coal namely U.S., Russian and Colombian coals are investigated in this study. Post-combustion capture and storage (CCS) namely with amine FG+, and oxy-fuel with carbon capture and storage (oxy-fuel) are applied to a 650 MW pulverized combustion (PC) plant. The impacts of the Renewable Obligation Certificate (ROC) and carbon price (CP) policy in accelerating the CCS deploymen...

  1. Physicochemical properties and heavy metals leachability of fly ash from coal-fired power plant

    Institute of Scientific and Technical Information of China (English)

    Xiang Wei; Han Baoping; Zhou Dong; Nzihou Ange

    2012-01-01

    The physicochemical properties of fly ash from two kinds of coal-fired power plants were studied.Three aspects were examined:the micro-morphology,the mineral composition and the content of heavy met als.The results show that the fly ash from plants using a circulating fluidized bed are more irregular particles,while the particles from the plants using a pulverized coal-fired boiler are mainly spherical in shape.Quartz and mullite are the main crystalline phases in the ash.Clearly,both the technology and the coal used by a power plant can influence the mineral composition of the ash.The mineral composition of fly ash from a circulating fluidized bed is more complex than that from a pulverized coal-fired boiler.The quantity of elements found in the fly ash is greater than that found in the bottom ash for the same plant.Heavy metals are likely to be enriched in the fly ash.Heavy metal leachability was studied using two leaching methods.The results indicate that most of the heavy metals that leached during either batch leaching or column leaching experiments did not exceed the related maximum concentration standards.But Ni concentrations in the leachates from both batch and column tests exceed the standard.The highest excess rates in both tests were 572% and 497%,which levels might threaten the environment.

  2. Separation of unburned carbon from coal fly ash through froth flotation; Sekitanbai no shisshiki datsutanso gijutsu kaihatsu shiken

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, T. [Center for Coal Utilization, Japan, Tokyo (Japan); Murakami, T. [The Coal Mining Research Center, Japan, Tokyo (Japan)

    1996-09-01

    Coal ash tends to become containing more unburned carbon and porous substances depending on conditions of combustion, whose adverse effects to products due to water adsorbability, absorbability and color tones create obstacles in its utilization. Therefore, research and development works have been progressed on wet type carbon removing technology which is characterized in that coal is pulverized to preferable degrees and subjected to flotation. This paper reports the results obtained during fiscal 1995. The results may be summarized as follows: as a result of the comparison test on a column flotation machine and an FW type flotation machine of machine stirring type, the former machine showed better flotation efficiency; several methods were investigated on crushing as a treatment prior to flotation, whereas a mixer with greater circumferential speed and a homo mixer showed the highest efficiency; strength of the impact to the flotation efficiency was found to decrease in the order of pulp concentration > pretreatment time > collector addition ratio; and as a result of the evaluation on refined ash as a cement admixture and carbons as fuel, possibilities were found in them for practical application. 16 figs., 2 tabs.

  3. 1999 international ash utilization symposium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    112 papers were presented covering various aspects of the utilization of coal and other combustion products. Topics included fundamental chemistry and mineralogy, new products, health and environmental aspects, economic development issues, agricultural and mine reclamation applications, concrete and cement, and fly ash beneficiation technologies. Selected papers will be published in the journal 'Fuel'.

  4. Electrodialytic removal of Cd from biomass combustion fly ash

    DEFF Research Database (Denmark)

    Pedersen, Anne Juul; Ottosen, Lisbeth M.; Simonsen, Peter

    2004-01-01

    Due to a high concentration of Cd, biomass combustion fly ash often fails to meet the Danish legislative requirements for recycling on agricultural fields. In this work the potential of using the method Electrodialytic Remediation to reduce the concentration of Cd in different biomass combustion...... fly ashes was studied. Four fly ashes were investigated, originating from combustion of straw (two ashes), wood chips, and co-firing of wood pellets and fuel oil, respectively. One of the straw ashes had been pre-washed and was obtained suspended in water, the other ashes were obtained naturally dry...

  5. Developing Engineered Fuel (Briquettes) Using Fly Ash from the Aquila Coal-Fired Power Plant in Canon City and Locally Available Biomass Waste

    Energy Technology Data Exchange (ETDEWEB)

    H. Carrasco; H. Sarper

    2006-06-30

    The objective of this research is to explore the feasibility of producing engineered fuels from a combination of renewable and non renewable energy sources. The components are flyash (containing coal fines) and locally available biomass waste. The constraints were such that no other binder additives were to be added. Listed below are the main accomplishments of the project: (1) Determination of the carbon content of the flyash sample from the Aquila plant. It was found to be around 43%. (2) Experiments were carried out using a model which simulates the press process of a wood pellet machine, i.e. a bench press machine with a close chamber, to find out the ideal ratio of wood and fly ash to be mixed to get the desired briquette. The ideal ratio was found to have 60% wood and 40% flyash. (3) The moisture content required to produce the briquettes was found to be anything below 5.8%. (4) The most suitable pressure required to extract the lignin form the wood and cause the binding of the mixture was determined to be 3000psi. At this pressure, the briquettes withstood an average of 150psi on its lateral side. (5) An energy content analysis was performed and the BTU content was determined to be approximately 8912 BTU/lb. (6) The environmental analysis was carried out and no abnormalities were noted. (7) Industrial visits were made to pellet manufacturing plants to investigate the most suitable manufacturing process for the briquettes. (8) A simulation model of extrusion process was developed to explore the possibility of using a cattle feed plant operating on extrusion process to produce briquettes. (9) Attempt to produce 2 tons of briquettes was not successful. The research team conducted a trial production run at a Feed Mill in La Junta, CO to produce two (2) tons of briquettes using the extrusion process in place. The goal was to, immediately after producing the briquettes; send them through Aquila's current system to test the ability of the briquettes to flow

  6. Ash behavior and de-fluidization in low temperature circulating fluidized bed biomass gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas

    . It was observed that of the total fuel ash entering the system, a large fraction (40-50%) of the ash was retained in the secondary cyclone bottoms and a lower amount (8-10%) was released as dust in the exit gas; the residual ash was accumulated within the fluidized bed system. A dominant fraction of alkali...... by the ash particle size and the cut size of the primary and secondary cyclones. A model accounting for the ash collection by the plant cyclones was developed which predicted the product gas ash particle release reasonably well. The present work also aims to understand the effect of biomass fuel ash...

  7. Iron-containing phases in fly ashes from different combustion systems

    Directory of Open Access Journals (Sweden)

    Szumiata Tadeusz

    2015-03-01

    Full Text Available The investigations of iron-containing phases existing in fly ashes were performed using transmission Mössbauer spectrometry. The examined samples of fly ashes were collected from different coal combustion systems, that is, stoker-fired boiler in municipal heating plant and pulverized coal boiler in power plant. Several phases are identified in the samples: iron oxides, paramagnetic aluminosilicate glass with Fe3+ ions and Al2O4-type spinel with Fe2+ ions. It was pointed out that proportions of contents of phases strongly depend not only on the combustion temperature but also on the way of ash collection.

  8. Combustion experiments in a small furnace using natural biogenic solid fuels. Emissions and ash quality. Final report; Verbrennungsversuche mit naturbelassenen biogenen Festbrennstoffen in einer Kleinfeuerungsanlage. Emissionen und Aschequalitaet. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Launhardt, T.; Hartmann, H.; Link, H.; Schmid, V.

    2000-09-01

    Emissions and ash qualities of the fuels were compared in order to assess their pollutant emissions CO, dust, C{sub n}H{sub m}, NO{sub x}, particle size distribution of airborne dust, organic and inorganic chlorinated pollutants (including PCDD/F), PAH and heavy metals. Quality characteristics of the fuels and ashes were investigated as well (nutrient and pollutant concentrations including heavy metals, chlorine, PCDD/F, PAH). The focus was on agricultural biomass, which was compared with chopped pinewood. [German] Ziel des Messvorhabens ist eine umfassende Analyse der Emissionen und der Aschenqualitaet beim Einsatz verschiedener biogener Festbrennstoffe in einer Kleinfeuerungsanlage (50 kW{sub th}). Dadurch soll eine vergleichende Bewertung der unterschiedlichen Brennstoffarten und Aufbereitungsformen (Pellet, Haeckselgut) moeglich werden und eine generelle Aussage ueber das Niveau des Schadstoffausstosses inklusive hochtoxischer organischer Komponenten abgeleitet werden. Ergaenzend dazu soll eine Quantifizierung moeglicher Einfluesse durch den Wassergehalt im Brennstoff und die Heizlast der Feuerungsanlage vorgenommen werden. Zielgroessen der Untersuchung sind der Wirkungsgrad der Feuerungsanlage, die Standard-Emissionsgroessen CO, Staub, C{sub n}H{sub m} und NO{sub x}, die Partikelgroessenverteilung des Flugstaubes, organisch und anorganisch chlorierte Schadstoffe (u.a. PCDD/F), PAK und Schwermetalle. Zusaetzlich werden eine Reihe von Qualitaetsmerkmalen im Brennstoff und in den Aschen betrachtet (Naehr- und Schadstoffgehalte, einschliesslich Schwermetalle, Chlor, PCDD/F, PAK). Im Vordergrund stehen die Biomassebrennstoffe, die speziell in der Landwirtschaft erzeugt werden. Sie werden mit dem Referenzbrennstoff Fichtenhackgut verglichen. (orig.)

  9. Flat-flame burner studies of pulverized-coal combustion. Experimental results on char reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Peck, R.E.; Shi, L.

    1996-12-01

    Structure of laminar, premixed pulverized-coal flames in a 1-D reactor has been studied with emphasis on char reactivity. A 1.1-meter-long tube furnace accommodated high-temperature environments and long residence times for the laminar flames produced by a flat-flame, coal-dust burner. Experiments were conducted at different operating conditions (fuel type/size, fuel-air ratio). Measurements included solid sample composition, major gas species and hydrocarbon species concentrations, and gas- and particle-phase line-of-sight temperatures at different axial locations in flames. Degree of char burnout increased with coal volatiles content and decreased with coal particle size. Combustion in furnace was in oxidizer-deficient environment and higher burnout was achieved as the fuel-air ratio neared stoichiometric. For 0-45 {mu}m particles most of the fixed carbon mass loss occurred within 5 cm of the furnace inlet, and char reaction was slow downstream due to low oxidizer concentrations. Fixed carbon consumption of the 45-90 {mu}m particles generally was slower than for the small particles. About 40%-80% of the fixed carbon was oxidized in the furnace. Primary volatiles mass loss occurred within the first 4.5 cm, and more than 90% of the volatiles were consumed in the flames. The flames stabilized in the furnace produced less CH{sub 4} and H{sub 2} in the burnt gas than similar unconfined flames. NO concentrations were found to decrease along the furnace and to increase with decreasing fuel/air ratio. Temperature measurement results showed that gas-phase temperatures were higher than solid-phase temperatures. Temperatures generally decreased with decreasing volatiles content and increased as the equivalence ratio approached one. The results can be used to interpret thermochemical processes occurring in pulverized-coal combustion. (au) 15 refs.

  10. Trace element emissions when firing pulverized coal in a pilot-scale combustion facility

    Energy Technology Data Exchange (ETDEWEB)

    Miller, S.F.; Wincek, R.T.; Miller, B.G.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States)

    1998-04-01

    Title Ed of the Clean Air Act Amendments of 1990 designates 189 hazardous air pollutants (HAPs). Fourteen of the 189 substances identified are: antimony (Sb), beryllium (Be), chlorine (0), cobalt (Co), manganese (Mn), nickel (Ni), selenium (Se), fluorine (F), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and phosphorous (P). Eleven of these elements have been detected in the flue gas of pulverized coal-fired utility boilers. Currently there are no regulations that limit the emissions of these elements during coal combustion in utility- or industrial-scale boilers. Given the growing body of risk assessment data on these elements and their impact on the environment and human health, it is possible that regulations on emission levels for certain elements will be imposed. A knowledge of the occurrence of trace elements in coal and their behavior during combustion is essential to predict emissions and to develop control technologies for remediation. The partitioning of trace elements during combustion can be traced to their volatility within the system. For purposes of this paper, the classification of trace elements summarized by Clarke and Sloss will be used: Group I elements, i.e., elements that are not easily volatilized and form larger bottom ash and fly ash particles; Group H elements, i.e., elements that are partially or completely volatilization followed by condensation as small particles or on the surface of small particles; and Group III elements, i.e., elements that are readily volatilized and usually remain in the gas phase system.

  11. The behavior of ash species in suspension fired biomass boilers

    DEFF Research Database (Denmark)

    Jensen, Peter Arendt

    of advanced deposit probe measurements have been conducted on biomass powerplants. The measurements have provided insight into the relations between the chemical composition of fuel ash, fly ash and deposits. Furthermore the measurements have provided quantitative data on deposit formation rates as a function...... the interface to the steam tube metal surface. Especially an increased tube temperature makes it more demanding to remove the ash deposit. Modelling of the deposit formation process have been developed by combining sub-models of the ash formation process, the condensation of ash species on tube surfaces, ash...... particle deposition, heat transfer in the deposit and deposit sintering. The model mainly providesinformation on how changes in fuel ash composition and local conditions influences depositformation rate and deposit chemistry. Comparison of the modeling results with laboratory andfull scale data shows...

  12. Experimental investigation on NO{sub x} emission and carbon burnout from a radially biased pulverized coal whirl burner

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Shan; Hui, Shi' en; Zhou, Qulan; Xu, Tongmo; Hu, Hongli [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Taisheng [Dongfang Boiler Group Co., Ltd., Zigong, Sichuan 643001 (China)

    2009-09-15

    Experiments have been performed on 1 MW pulverized coal (pc) furnace in order to investigate the characteristics of coal combustion and NO{sub x} emission from a new type of radially biased dual register whirl burner. The burner is characterized by a primary air pipe with a continuously changing cross-section and an impact ring. The mixture of pulverized coal and air inside the primary pipe is split into two streams, which are the outer pc rich annular jet and the inner pc lean annular jet respectively. Three Chinese coals, which are high rank bituminous coal, low rank bituminous coal and meager coal respectively, are used in the experiments. We examine the influences of various parameters such as the relative position of the over-fire air (OFA) nozzle, over-fire air ratio (19.1%), primary air ratio, inner secondary air ratio, outer secondary air ratio, inner secondary air swirling intensity, and outer secondary air swirling intensity on NO{sub x} formation and unburned carbon in fly ash. With the primary air ratio increasing from 13.4% to 23.4%, the value of the NO{sub x} emission of the SH coal decreases by 26.7% at first, and then increases by 21.7%. In contrast, the value of the carbon in fly ash (C{sub FA}) increases by 40.1% at first, and then decreases by 58.3%. According to the experimental results, the influence of each individual parameter on NO{sub x} formation and unburned carbon in fly ash agrees well with the existing literature. In this study, the influences of various combinations of these parameters are also examined, thus providing some reference for the design of the radial biased whirl burner, the configuration of the furnace and the distribution of the air. (author)

  13. Experimental study on ignition characteristics of pulverized coal under high-temperature oxygen condition

    Science.gov (United States)

    Liu, G. W.; Liu, Y. H.; Dong, P.

    2016-08-01

    The high-temperature oxygen ignition technology of pulverized coal, which can replace the oil gun and achieve oil-free pulverized coal ignition by mixing the high- temperature oxygen and the pulverized coal stream directly, was proposed and a relevant ignition experimental system was built. The ignition characteristics of pulverized coal under high-temperature oxygen condition were investigated: the ignition process was described and analyzed, the influence of relevant parameters on the pulverized coal stream ignition were obtained and analyzed. The results showed: when the oxygen heating temperature is over 750 °C, the pulverized coal stream could be ignited successfully by high-temperature oxygen; increasing the pulverized coal concentration, primary air temperature and oxygen volume flow rate or decreasing the primary air velocity is helpful for the ignition and combustion of the pulverized coal stream.

  14. Pulverized coal burnout in blast furnace simulated by a drop tube furnace

    Energy Technology Data Exchange (ETDEWEB)

    Du, Shan-Wen [Steel and Aluminum Research and Development Department, China Steel Corporation, Kaohsiung 812 (China); Chen, Wei-Hsin [Department of Greenergy, National University of Tainan, Tainan 700 (China); Lucas, John A. [School of Engineering of the University of Newcastle, Callaghan, NSW 2308 (Australia)

    2010-02-15

    Reactions of pulverized coal injection (PCI) in a blast furnace were simulated using a drop tube furnace (DTF) to investigate the burnout behavior of a number of coals and coal blends. For the coals with the fuel ratio ranging from 1.36 to 6.22, the experimental results indicated that the burnout increased with decreasing the fuel ratio, except for certain coals departing from the general trend. One of the coals with the fuel ratio of 6.22 has shown its merit in combustion, implying that the blending ratio of the coal in PCI operation can be raised for a higher coke replacement ratio. The experiments also suggested that increasing blast temperature was an efficient countermeasure for promoting the combustibility of the injected coals. Higher fuel burnout could be achieved when the particle size of coal was reduced from 60-100 to 100-200 mesh. However, once the size of the tested coals was in the range of 200 and 325 mesh, the burnout could not be improved further, resulting from the agglomeration of fine particles. Considering coal blend reactions, the blending ratio of coals in PCI may be adjusted by the individual coal burnout rather than by the fuel ratio. (author)

  15. Gasification in pulverized coal flames. Final report (Part I). Pulverized coal combustion and gasification in a cyclone reactor: experiment and model

    Energy Technology Data Exchange (ETDEWEB)

    Barnhart, J. S.; Laurendeau, N. M.

    1979-05-01

    A unified experimental and analytical study of pulverized coal combustion and low-BTU gasification in an atmospheric cyclone reactor was performed. Experimental results include several series of coal combustion tests and a coal gasification test carried out via fuel-rich combustion without steam addition. Reactor stability was excellent over a range of equivalence ratios from .67 to 2.4 and air flowrates from 60 to 220 lb/hr. Typical carbon efficiencies were 95% for air-rich and stoichiometric tests and 80% for gasification tests. The best gasification results were achieved at an equivalence ratio of 2.0, where the carbon, cold gas and hot gas efficiencies were 83, 45 and 75%, respectively. The corresponding product gas heating value was 70 BTU/scf. A macroscopic model of coal combustion in the cyclone has been developed. Fuel-rich gasification can also be modeled through a gas-phase equilibrium treatment. Fluid mechanics are modeled by a particle force balance and a series combination of a perfectly stirred reactor and a plug flow reactor. Kinetic treatments of coal pyrolysis, char oxidation and carbon monoxide oxidation are included. Gas composition and temperature are checked against equilibrium values. The model predicts carbon efficiency, gas composition and temperature and reactor heat loss; gasification parameters, such as cold and hot gas efficiency and make gas heating value, are calculated for fuel-rich conditions. Good agreement exists between experiment and theory for conditions of this investigation.

  16. Pb-210 and Po-210 atmospheric releases via fly ash from oil shale-fired power plants.

    Science.gov (United States)

    Vaasma, Taavi; Loosaar, Jüri; Gyakwaa, Francis; Kiisk, Madis; Özden, Banu; Tkaczyk, Alan H

    2017-03-01

    During high temperature processes in the furnace volatile and semi-volatile elements and radionuclides are partially emitted to the environment, depending on their chemical form in the original fuel, the technological set-up of the combustion system, and the prevailing combustion conditions. Two of the world's largest oil shale-fired power plants (PPs) have been operational in Estonia from the 1960s, during which time creation of significant environmental emissions and waste containing naturally occurring radionuclides has occurred. Pb-210 and (210)Po are considered natural radionuclides with the highest emission rates from PPs and possess elevated potential radiation exposure risks to humans and the environment. These radionuclides have the highest activity concentration values in fine ash fractions, especially in fractions remaining below 2.5 μm. To determine the activity concentrations of (210)Pb and (210)Po in the PPs' outlet, sampling was conducted from boilers operating on pulverized fuel (PF) technology with novel integrated desulphurization (NID) system and bag filters as well as with electrostatic precipitators (ESPs). The (210)Pb and (210)Po activity concentrations remained around 300 Bq kg(-1) for the NID system compared to 60-80 Bq kg(-1) in the ESP system. The dominant ash fraction in both systems was PM2.5, constituting over 50% of the fly ash mass collected from the outlet. The authors estimate that the total atmospherically emitted activity for the modernized PPs remains dominantly below 1% of the activity that is inserted via fuel. The implementation of higher efficiency purifications systems has significantly reduced the negative effect of these PPs. Based on annually emitted fly ash and boilers' working hours, the (210)Pb and (210)Po activity released relative to energy production were up to 68.3 kBq GWhel(-1) for (210)Pb and 64.6 kBq GWhel(-1) for (210)Po. These values are 1 to 2 orders of magnitude lower compared to the situation in the 1980s

  17. The Nano Pulverization of Traditional Chinese Medicine Liuwei Dihuang

    Institute of Scientific and Technical Information of China (English)

    MA Peiyan; FU Zhengyi; SU Yanli; MA Jingjing

    2006-01-01

    The crude drug of Liuwei Dihuang was pulverized to nano particles to improve its bioavailability. The appropriate technique parameters were studied. Paeonol, typical marker of Liuwei Dihuang, was extracted with organic solvent in ultrasonic and its content was determined by HPLC. The appropriate techniques parameters are as follows: rotating speed control 1200 r/min, grinding time control 50min and mass percent concentration control 3.8%. The experimental results show that the average particle diameter is 161.9 nm and the great majority of the plant cell wall is broken into pieces after nano pulverization. The extraction efficiency of paeonol is increased by 23.5%.

  18. Comparison of Charging Characteristics of Polymerized and Pulverized Toners

    Institute of Scientific and Technical Information of China (English)

    Yasushi Hoshino; Tsunenori Nakanishi; Ye Zhou; Hidetaka Ishihara

    2004-01-01

    Toner charge is very important in electrophotographic printing process. Although many studies on toner charging mechanism have been carried out, the mechanism is very complex and the understanding of toner charging characteristics is not yet sufficient. Toner charge distribution is measured by E-SPART (electrical single particle aerodynamic relaxation time) analyzer, which can measure the size and charge of toner. The measured toners are polymerized and pulverized type. Charging is carried out as follows: the toner is mixed with the carrier and the mixture is bottled into the roller, and mixed by rotating the roller. Toner charge dependences on toner wt% are compared between polymerized and pulverized toner.

  19. Development of Small-Scale CHP Plant with a Wood Powder-Fueled Stirling Engine

    Science.gov (United States)

    Sato, Katsura; Ohiwa, Norio; Ishikawa, Akira; Shimojima, Hidetoshi; Nishiyama, Akio; Moriya, Yoichi

    Small-scale biomass CHP (combined heat and power) plants are in demand for environmental reasons - particularly systems fueled by wood waste, which are simple to operate and require no maintenance while having high thermal efficiency similar to oil-fired units. A 55kWe Stirling engine CHP system, combined with a simplified biomass combustion process that uses pulverized wood powder has been developed to meet these requirements. Wood powder of less than 500 μm was mainly used in these tests, and a combustion chamber length of 3 m was applied. Under these conditions, the air ratio can be reduced to 1.1 without increasing CO emissions by less than 10 ppm, and with combustion efficiency of 99.9%. Under the same conditions, NOx emissions are estimated to be less than 120 ppm (on the basis of 6% O2). Wood powder was confirmed to have excellent properties as a fuel for Stirling engines. The 55 kWe Stirling engine performance test was carried out to optimize the operating condition of wood powder burners. The status of Stirling engine operation at a full load with 55 kWe was stable, and start-up and shut -down operations were easy to perform. Operational status was evaluated as being excellent, except for an ash fouling problem in the Stirling engine heater tubes. Ash fouling characteristics were considered in the final stage of the demonstration test. This paper summarizes the wood powder combustion test and Stirling engine performance test. Furthermore, the ash fouling data is shown and the mechanism of ash fouling in heater tubes is discussed.

  20. Oil ash corrosion; A review of utility boiler experience

    Energy Technology Data Exchange (ETDEWEB)

    Paul, L.D. (Babcock and Wilcox Co., Alliance, OH (United States)); Seeley, R.R. (Babcock and Wilcox Canada Ltd., Cambridge, ON (Canada))

    1991-02-01

    In this paper a review of experience with oil ash corrosion is presented along with current design practices used to avoid excessive tube wastage. Factors influencing oil ash corrosion include fuel chemistry, boiler operation, and boiler design. These factors are interdependent and determine the corrosion behavior in utility boilers. Oil ash corrosion occurs when vanadium-containing ash deposits on boiler tube surfaces become molten. These molten ash deposits dissolve protective oxides and scales causing accelerated tube wastage. Vanadium is the major fuel constituent responsible for oil ash corrosion. Vanadium reacts with sodium, sulfur, and chlorine during combustion to produce lower melting temperature ash compositions, which accelerate tube wastage. Limiting tube metal temperatures will prevent ash deposits from becoming molten, thereby avoiding the onset of oil ash corrosion. Tube metal temperatures are limited by the use of a parallel stream flow and by limiting steam outlet temperatures. Operating a boiler with low excess air has helped avoid oil ash corrosion by altering the corrosive combustion products. Air mixing and distribution are essential to the success of this palliative action. High chromium alloys and coatings form more stable protective scaled on tubing surfaces, which result in lower oil ash corrosion rates. However, there is not material totally resistant to oil ash corrosion.

  1. The pulverization and handling of soft plastics for energy recovery; Soenderdelning och hantering av mjuka plaster foer energiutvinning

    Energy Technology Data Exchange (ETDEWEB)

    Wiklund, Sven-Erik

    2000-10-01

    The purpose of the project has primarily been to investigate suitable equipment (mills, crushers, shredders) for the pulverization of different types of soft plastics from the agricultural sector (large sacks and silage plastic) and the peat extraction industry (plastic covers) with the aim of being able to use the plastic material as fuel in conventional solid waste-fired plants. Many of the mills that are used for pulverizing different types of biofuel have proved not to be particularly suitable for soft plastics. The project has comprised the following: * Contact with a number of plant owners with different types of plants (grate, CFB and BFB boilers) for a review of existing fuel handling and fuel feed equipment as well as the demands they make on the fuel that is to be fired. * Contact with Trio Plast concerning previous tests carried out in connection with the collection, baling, handling, pulverization and combustion of plastics from the agricultural sector. * Contact with mill suppliers for participation in the tests and for feedback on experience gained in connection with the pulverization of soft plastics. * Choice of a suitable plant for practical trials based on contact with the above plant owners as a reference group. * Practical trials in 5 mills with the pulverization of soft plastics from agriculture (silage plastic and large sacks) as well as plastic from peat extraction (plastic covers) and * Evaluation of technical, economic, energy-related and environmental preconditions. Following contact with several owners of solid waste-fired combustion plants, and after hearing their opinions, it became clear that many of them were doubtful about the combustion of plastic. They are primarily afraid of tripping superheaters, etc. Consequently, two plants without superheaters, one in Oestersund and the other in Malmoe, were chosen for the tests. The mills that were tested were: * A SIM mill from WahIkvist, Oedeshoeg Plant - a mobile slow-action pulverizer for

  2. Numerical Simulation of Combustion Characteristics of a 300 MW Blast Furnace Gas/Pulverized Coal Combined Combustion Boiler%300MW煤粉/高炉煤气混燃锅炉燃烧特性数值模拟

    Institute of Scientific and Technical Information of China (English)

    王春波; 魏建国; 盛金贵; 李艳奇

    2012-01-01

    Blast furnace gas(BFG) produced from steel mill is a low heat value fuel,which combined with pulverized coal to combust in boiler is one of effective ways.However,the combustion characteristics would be changed greatly when compared with only pulverized coal combustion.For example,superheaters and reheaters are easy to excess rated temperatures and carbon content in fly ash will become higher,etc.All these problems lead to its limited application today.Take a 300MW BFG/pulverized coal boiler for example,the combustion characteristics were simulated by means of two mixture fractions way.The pure coal condition and three BFG ratio: 10%,20% and 30% conditions were investigated.It shows the temperature level in boiler is lowered obviously when BFG was mixed into boiler.For example,the maximal temperature is lowered about 81K when BFG ratio is 10% for a boiler section.Also,the temperature becomes lower with the BFG ratio.When BFG was mixed into boiler the flue gases volume would be increased.So,the actual stay time for pulverized coal in boiler will be shortened and it is more difficulty for coal to combust completely.Aslo,it is helpfully for control NO emission when BFG was mixed into boiler.%钢厂高炉煤气是一种低热值燃料,它和煤粉在炉内掺烧是其一种有效的利用途径。但煤粉掺烧高炉煤气后燃烧特性与纯煤粉燃烧有很大不同,掺烧过程中易发生过/再热器超温、飞灰含碳量过高等问题,导致其在大型锅炉上的应用很少。针对某钢厂300MW四角切圆煤粉/高炉煤气混燃锅炉,使用二混合分数法对其燃烧特性进行数值模拟。对比研究了纯燃煤工况和高炉煤气掺烧量分别为10%、20%、30%的工况,发现掺烧高炉煤气时炉内温度水平有明显下降(如,掺烧10%高炉煤气时截面最高温度降低81K),且随着掺烧量的增加而加剧,但下降的趋势变缓。掺烧高炉煤气后产生烟气量增多,炉膛出口烟速有明显增加,

  3. NITRIC OXIDE FORMATION DURING PULVERIZED COAL COMBUSTION

    Science.gov (United States)

    Data on the overall conversion of coal-nitrogen to NOx were obtained at 1250 K and 1750 K for a residence time of one second. The conversion of coal-nitrogen to NOx decreased monotonically with increasing fuel/oxygen equivalence ratio and decreased slightly with increasing temper...

  4. Associative properties of {sup 137}Cs in biofuel ashes

    Energy Technology Data Exchange (ETDEWEB)

    Ravila, A.; Holm, E. [Lund Univ. (Sweden). Dept. of Radiation Physics

    1999-07-01

    The present study aims to reveal how radiocesium is associated to the ash particles derived from biofuel combustion. A sequential extraction procedure was carried out for the characterisation of radiocesium speciation in ash generated by different fuels and burner types. The ash types considered were fly ash and bottom ash collected from Swedish district heating plants using bark wood or peat as fuel. A fraction of the radiocesium in biofuel ash can easily become solubilised and mobilised by water and also, a significant fraction of the radionuclides can be bound to the ash particles in cation-exchangeable forms. Therefore, at using the ash derived from biofuels to recycle mineral nutrients for forestry or short rotation coppicing, radiocesium solubilised and leached from the ash by rains has a potential to rather quickly enter the rooting zone of forest vegetation or energy crops. On the other hand, radiocesium strongly bound to the ash will migrate slowly into the soil column with the successive accumulation of litter and in the process act to maintain the external dose rate at an elevated level for a long time. The results of the sequential extraction procedure and activity determination of the different extracted fractions implies that the bioavailable fraction of radiocesium in ash from bark, wood or peat is in the range between 20-85% of the total ash contents. Peat ash collected from a powder burner strongly retained a large fraction (70-90%) of its radiocesium content while the peat ash from a continuos fluidized bed type burner retained nearly 100% of the radiocesium in the bottom ash and only about 15% in the fly ash.

  5. Characterization of ashes from biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, F.J.; Hansen, L.A. [Technical Univ. of Denmark. Dept. of Chemical Engineering (Denmark); Soerensen, H.S. [Geological Survey of Denmark and Greenland (Denmark); Hjuler, K. [dk-TEKNIK. Energy and Environment (Denmark)

    1998-02-01

    One motivation for initiating the present project was that the international standard method of estimating the deposit propensity of solid fuels, of which a number of variants exist (e.g. ISO, ASTM, SD, DIN), has shown to be unsuitable for biomass ashes. This goal was addressed by the development of two new methods for the detection of ash fusibility behaviour based on Simultaneous Thermal Analysis (STA) and High Temperature Light Microscopy (HTLM), respectively. The methods were developed specifically for ashes from biofuels, but are suitable for coal ashes as well. They have been tested using simple salt mixtures, geological standards and samples from straw CHP and coal-straw PF combustion plants. All samples were run in a nitrogen atmosphere at a heating rate of 10 deg. C/min. In comparison with the standard method, the new methods are objective and have superior repeatability and sensitivity. Furthermore, the two methods enable the melting behavior to be characterized by a continuous measurement of melt fraction versus temperature. Due to this two-dimensional resolution of the results, the STA and HTLM methods provide more information than the standard method. The study of bottom ash and fly ash as well as deposit samples from straw test firings at the Haslev and Slagelse Combined Heat and Power plants resulted in a better understanding of mineral behaviour during straw grate firing. In these tests a number of straws were fired which had been carefully selected for having different qualities with respect to sort and potassium and chlorine contents. By studying bottom ashes from Slagelse it was found that the melting behaviour correlated with the deposition rate on a probe situated at the outlet part of the combustion zone. (EG)

  6. The effect of pulverization on the albedo of lunar rocks

    NARCIS (Netherlands)

    Minnaert, Marcel Gilles Jozef

    1969-01-01

    Measures of the albedo under full-moon conditions have been made on two samples of very dark rocks, pulverized and sieved so as to obtain powders of different grain size. Below a size of 0.05 mm the albedo suddenly increases, obviously because the individual grains become transparent. By a rough cal

  7. PROJECT OF COAGULANT DISPENSER IN PULVERIZATION AERATOR WITH WIND DRIVE

    Directory of Open Access Journals (Sweden)

    Ewa Osuch

    2017-09-01

    Full Text Available Lakes are one of most important freshwater ecosystems, playing significant role in functioning of nature and human economy. Swarzędzkie Lake is good example of ecosystem, which in last half-century was exposed to the influence of strong anthropopressure. Direct inflow of sewage with large number of biogens coming to the lake with water of inflows caused distinct disturbance of its functioning. In autumn 2011 restoration begined on Swarzędzkie Lake for reduction of lake trophy and improvement of water quality. For achieving better and quicker effect, simultaneously combination of some methods was applied, among others method of oxygenation of over-bottom water with help of pulverization aerator and method of precise inactivation of phosphorus in water depths. Characterization and analysis of improved coagulant dispenser applying active substance only during work of pulverization aerator is the aim of this thesis. Principle of dispenser work, its structure and location in pulverization aerator were explained. It was stated, that introduction to water a factor initiating process of phosphorus inactivation causes significant reduction of mineral phosphorus in water and size of coagulant dose correlates with intensity of work of pulverization aerator with wind drive.

  8. The effect of pulverization on the albedo of lunar rocks

    NARCIS (Netherlands)

    Minnaert, Marcel Gilles Jozef

    Measures of the albedo under full-moon conditions have been made on two samples of very dark rocks, pulverized and sieved so as to obtain powders of different grain size. Below a size of 0.05 mm the albedo suddenly increases, obviously because the individual grains become transparent. By a rough

  9. Ash and heavy metals in fluidized bed-combustion; Tuhka ja raskasmetallit puuperaeisen jaetteen kerrosleijupoltossa

    Energy Technology Data Exchange (ETDEWEB)

    Kaessi, T.; Aittoniemi, P. [IVO International, Vantaa (Finland)

    1996-12-01

    Combustion ashes and submicron fly ash particles were characterized in two industrial boilers (bubbling vs. circulating fluidized bed) burning paper mill deinking sludge and bark or wood as support fuel. Bulk samples from fly ash, circulating ash and bottom ash were analyzed. Fine particles in fly ash were monitored and sampled for microscopic studies. The mass size distribution of fly ash was measured and the chemical composition according to particle size was analyzed. The results showed that ash consists of large and friable clusters formed by sintering of small mineral particles originating from paper fillers. Very few ash particles were fused and they were found only among the smallest particles. No agglomerates of fused particles were found. If the residence time in furnace is long enough sintering may proceed further and ash structure grows more dense. No indication of ash vaporization was detected. These results were similar for bubbling and circulating fluidized bed boilers. (author)

  10. Ash chemistry and sintering, verification of the mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Skrifvars, B.J. [Aabo Akademi, Turku (Finland)

    1996-12-01

    In this project four sintering mechanisms have been studied, i.e., partial melting with a viscous liquid, partial melting with a non-viscous liquid, chemical reaction sintering and solid state sintering. The work has aimed at improving the understanding of ash sintering mechanisms and quantifying their role in combustion and gasification. The work has been oriented in particular on the understanding of biomass ash behavior. The work has not directly focused on any specific technical application. However, results can also be applied on other fuels such as brown coal, petroleum coke, black liquor and different types of wastes (PDF, RDF, MSW). In one part of study the melting behavior was calculated for ten biomass ashes and compared with lab measurements of sintering tendencies. The comparison showed that the T{sub 15} temperatures, i.e. those temperatures at which the ashes contained 15 % molten phase, correlated fairly well with the temperature at which the sintering measurements detected sintering. This suggests that partial melting can be predicted fairly accurate for some ashes already with the today existing thermodynamic calculation routines. In some cases, however the melting calculations did not correlate with the detected sintering temperatures. In a second part detailed measurements on ash behavior was conducted both in a semi full scale CFB and a lab scale FBC. Ashes and deposits were collected and analyzed in several different ways. These analyses show that the ash chemistry shifts radically when the fuel is shifted. Fuels with silicate based ashes behaved totally different than those with an oxide or salt based ash. The chemistry was also affected by fuel blending. The ultimate goal has been to be able to predict the ash thermal behavior during biomass thermal conversion, using the fuel and ash elemental analyses and a few operational key parameters as the only input data. This goal has not yet today been achieved. (author)

  11. Modelling of pulverized coal boilers: review and validation of on-line simulation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Diez, L.I.; Cortes, C.; Campo, A. [University of Zaragoza, Zaragoza (Spain). Centro de Investigacion de Recursos y Consumos Energeticos (CIRCE)

    2005-07-01

    Thermal modelling of large pulverized fuel utility boilers has reached a very remarkable development, through the application of CFD techniques and other advanced mathematical methods. However, due to the computational requirements, on-line monitoring and simulation tools still rely on lumped models and semiempirical approaches, which are often strongly simplified and not well connected with sound theoretical basis. This paper reviews on-line modelling techniques, aiming at the improvement of their capabilities, by means of the revision and modification of conventional lumped models and the integration of off-line CFD predictions. The paper illustrates the coherence of monitoring calculations as well as the validation of the on-line thermal simulator, starting from real operation data from a case-study unit. The outcome is that it is possible to significantly improve the accuracy of on-line calculations provided by conventional models, taking into account the singularities of large combustion systems and coupling offline CFD predictions for selected scenarios.

  12. Pulverized coal torch combustion in a furnace with plasma-coal system

    Science.gov (United States)

    Messerle, V. E.; Ustimenko, A. B.; Askarova, A. S.; Nagibin, A. O.

    2010-09-01

    Combustion of a pulverized coal torch has been numerically simulated on the basis of the equations of multicomponent turbulent two-phase flows. The results of three-dimensional simulation of conventional and plasma activated coal combustion in a furnace are presented. Computer code Cinar ICE was verified at coal combustion in the experimental furnace with thermal power of 3 MW that was equipped with plasma-fuel system. Operation of the furnace has been studied at the conventional combustion mode and with plasma activation of coal combustion. Influence of plasma activation of combustion on thermotechnical characteristics of the torch and decrease of carbon loss and nitrogen oxides concentration at the furnace outlet has been revealed.

  13. A numerical study of pulverized coal ignition by means of plasma torches in air-coal dust mixture ducts of utility boiler furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Belosevic, S.; Sijercic, M.; Stefanovic, P. [Institute for Nuclear Science Vinca, Belgrade (Serbia)

    2008-04-15

    Paper presents selected results of numerical simulation of processes in air-coal dust mixture duct of pulverized coal utility boiler furnace with plasma-system for pulverized coal ignition and combustion stabilization. Application of the system in utility boiler furnaces promises to achieve important savings compared with the use of heavy oil burners. Plasma torches are built in air-coal dust mixture ducts between coal mills and burners. Calculations have been performed for one of rectangular air-coal dust mixture ducts with two opposite plasma torches, used in 210 MWe utility boiler firing pulverized Serbian lignite. The simulations are based on a three-dimensional mathematical model of mass, momentum and heat transfer in reacting turbulent gas-particle flow, specially developed for the purpose. Characteristics of processes in the duct are analyzed in the paper, with respect to the numerical results. The plasma-system thermal effect is discussed as well, regarding corresponding savings of liquid fuel. It has been emphasized that numerical simulation of the processes can be applied in optimization of pulverized coal ignition and combustion stabilization and enables efficient and cost-effective scaling-up procedure from laboratory to industrial scale.

  14. Physical Parameters Affecting the Emanation of RADON-222 from Coal Ash.

    Science.gov (United States)

    Barton, Terence Patrick

    The Rn-222 emanation coefficients for coal ash and parameters which affected them were measured. Samples of ash from both stoker fired and pulverized coal fired boilers were obtained. The stoker ash samples were mechanically separated into size fractions. The pulverized samples were too fine for mechanical sizing and were categorized qualitatively according to origin. Bulk density of the stoker fractions was measured and ranged from .488 to .944 g-cm('-3), increasing as a function of decreasing particle size. Bulk density of the pulverized ash ranged from 1.254 to 1.520 g-cm('-3). Specific gravity of the stoker fractions ranged from 2.017 to 2.390 g-cm('-3), also increasing as a function of decreasing particle size. Specific gravity of the pulverized ash ranged from 2.357 to 2.588 g-cm(' -3). Ra-226 content of the samples was determined by gamma spectrometric analysis of the 352-KeV gamma of Pb -214 and the 609-KeV gamma of Bi-214 from sealed samples of ash. Ra-226 concentrations in the stoker fractions ranged from 11.82 to 16.77 dpm-g('-1), increasing as a function of decreasing particle size. Ra-226 concentrations in the pulverized ash ranged from 6.44 to 7.59 dpm-g(' -1). Scintillation cells were constructed out of commonly available materials and a commercial preparation of ZnS(Ag) scintillator. Emanation chambers which allowed for moderately large sample masses were constructed. The procedure used to measure emanation coefficients was shown to be insensitive to ingrowth time at greater than 3 days ingrowth and relatively insensitive to variations in sample porosity. Emanation coefficients of the stoker fractions were measured at moisture contents of 0, 1.0, 10, 20, and 40 percent by weight. Within each size fraction the emanation coefficient increased as a function of moisture content, ranging from 9.58 x 10('-4) to 4.13 x 10('-2) between 0 and 20 percent moisture, respectively. Emanation coefficients also increased as a function of decreasing particle size

  15. The effects of unburned carbon on radiative heat transfer in a pilot pulverized coal furnace -- Numerical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Liu Zhaohui; Xing Huawei; Zhou Yingbiao; Zheng Chuguang [National Lab. of Coal Combustion, Wuhan (China)

    1997-12-31

    This paper investigates the possible effect of residue char on the radiative heat transfer in a pilot furnace. Firstly, a program is constructed to incorporate radiative properties of particles in solving the radiative heat transfer, based on a computer code for predicting turbulent gas-solid flow and combustion. The radiative properties of single unburnt char are modeled by coated sphere model of Mie theory, while the local Planck average radiative properties of particle could be obtained by a scheme based on Lagrangian approach with particle turbulent dispersion, and the radiative heat transfer is solved by Discrete Transfer method. Then, comparisons are made among predicted results for a pilot-scale pulverized coal furnace by several particulate radiative properties models. It shows even for the pilot-scale furnace, the effect of particle concentration is more important than that of distinguishing between particles of char and ash. The residue carbon in ash has a tendency to enhance the radiative heat transfer for this case. The optimized burn-off rate to separate ash from char is near 0.65.

  16. Possibilities of utilizing power plant fly ashes

    Directory of Open Access Journals (Sweden)

    Mezencevová Andrea

    2003-09-01

    Full Text Available The burning of fossil fuels in industrial power stations plays a significant role in the production of thermal and electrical energy. Modern thermal power plants are producing large amounts of solid waste, mainly fly ashes. The disposal of power plant waste is a large environmental problem at the present time. In this paper, possibilities of utilization of power plant fly ashes in industry, especially in civil engineering, are presented. The fly ash is a heterogeneous material with various physical, chemical and mineralogical properties, depending on the mineralogical composition of burned coal and on the used combustion technology. The utilization of fly ashes is determined of their properties. The fineness, specific surface area, particle shape, density, hardness, freeze-thaw resistance, etc. are decisive. The building trade is a branch of industry, which employs fly ash in large quantities for several decades.The best utilization of fluid fly ashes is mainly in the production of cement and concrete, due to the excellent pozzolanic and cementitious properties of this waste. In the concrete processing, the fly ash is utilized as a replacement of the fine aggregate (fine filler or a partial replacement for cement (active admixture. In addition to economic and ecological benefits, the use of fly ash in concrete improves its workability and durability, increases compressive and flexural strength, reduces segregation, bleeding, shrinkage, heat evolution and permeability and enhances sulfate resistance of concrete.The aim of current research is to search for new technologies for the fly ash utilization. The very interesting are biotechnological methods to recovery useful components of fly ashes and unconventional methods of modification of fly ash properties such as hydrothermal zeolitization and mechanochemical modification of its properties. Mechanochemistry deals with physico - chemical transformations and chemical reactions of solids induced by

  17. Volcanic ash impacts on critical infrastructure

    Science.gov (United States)

    Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

    2012-01-01

    Volcanic eruptions can produce a wide range of hazards. Although phenomena such as pyroclastic flows and surges, sector collapses, lahars and ballistic blocks are the most destructive and dangerous, volcanic ash is by far the most widely distributed eruption product. Although ash falls rarely endanger human life directly, threats to public health and disruption to critical infrastructure services, aviation and primary production can lead to significant societal impacts. Even relatively small eruptions can cause widespread disruption, damage and economic loss. Volcanic eruptions are, in general, infrequent and somewhat exotic occurrences, and consequently in many parts of the world, the management of critical infrastructure during volcanic crises can be improved with greater knowledge of the likely impacts. This article presents an overview of volcanic ash impacts on critical infrastructure, other than aviation and fuel supply, illustrated by findings from impact assessment reconnaissance trips carried out to a wide range of locations worldwide by our international research group and local collaborators. ‘Critical infrastructure’ includes those assets, frequently taken for granted, which are essential for the functioning of a society and economy. Electricity networks are very vulnerable to disruption from volcanic ash falls. This is particularly the case when fine ash is erupted because it has a greater tendency to adhere to line and substation insulators, where it can cause flashover (unintended electrical discharge) which can in turn cause widespread and disruptive outages. Weather conditions are a major determinant of flashover risk. Dry ash is not conductive, and heavy rain will wash ash from insulators, but light rain/mist will mobilise readily-soluble salts on the surface of the ash grains and lower the ash layer’s resistivity. Wet ash is also heavier than dry ash, increasing the risk of line breakage or tower/pole collapse. Particular issues for water

  18. Low temperature magnetic characterisation of fire ash residues

    Science.gov (United States)

    Peters, C.; Thompson, R.; Harrison, A.; Church, M. J.

    Fire ash is ideally suited to mineral magnetic studies. Both modern (generated by controlled burning experiments) and archaeological ash deposits have been studied, with the aim of identifying and quantifying fuel types used in prehistory. Low temperature magnetic measurements were carried out on the ash samples using an MPMS 2 SQUID magnetometer. The low temperature thermo-remanence cooling curves of the modern ash display differences between fuel sources. Wood and well-humified peat ash display an increase in remanence with cooling probably related to a high superparamagnetic component, consistent with room temperature frequency dependent susceptibilities of over 7%. In comparison fibrous-upper peat and peat turf display an unusual decrease in remanence, possibly due to an isotropic point of grains larger than superparamagnetic in size. The differences have been successfully utilised in unmixing calculations to quantify fuel components within four archaeological deposits from the Northern and Western Isles of Scotland.

  19. Assessment of ecotoxicological risks of element leaching from pulverized coal ashes

    NARCIS (Netherlands)

    Jenner, H.A.

    1995-01-01

    This thesis describes the consequences of the disposal of the combustion residues of coal, especially the uptake of elements from such residues and their effects on various organisms. The effects on benthic organisms in fresh and in seawater are considered in the first two parts. The third

  20. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Edward K. Levy; Nenad Sarunac; Harun Bilirgen; Hugo Caram

    2006-03-01

    U.S. low rank coals contain relatively large amounts of moisture, with the moisture content of subbituminous coals typically ranging from 15 to 30 percent and that for lignites from 25 and 40 percent. High fuel moisture has several adverse impacts on the operation of a pulverized coal generating unit, for it can result in fuel handling problems and it affects heat rate, stack emissions and maintenance costs. Theoretical analyses and coal test burns performed at a lignite fired power plant show that by reducing the fuel moisture, it is possible to improve boiler performance and unit heat rate, reduce emissions and reduce water consumption by the evaporative cooling tower. The economic viability of the approach and the actual impact of the drying system on water consumption, unit heat rate and stack emissions will depend critically on the design and operating conditions of the drying system. The present project evaluated the low temperature drying of high moisture coals using power plant waste heat to provide the energy required for drying. Coal drying studies were performed in a laboratory scale fluidized bed dryer to gather data and develop models on drying kinetics. In addition, analyses were carried out to determine the relative costs and performance impacts (in terms of heat rate, cooling tower water consumption and emissions) of drying along with the development of optimized drying system designs and recommended operating conditions.

  1. Dynamic fracturing by successive coseismic loadings leads to pulverization in active fault zones

    Science.gov (United States)

    Aben, F. M.; Doan, M.-L.; Mitchell, T. M.; Toussaint, R.; Reuschlé, T.; Fondriest, M.; Gratier, J.-P.; Renard, F.

    2016-04-01

    Previous studies show that pulverized rocks observed along large faults can be created by single high-strain rate loadings in the laboratory, provided that the strain rate is higher than a certain pulverization threshold. Such loadings are analogous to large seismic events. In reality, pulverized rocks have been subject to numerous seismic events rather than one single event. Therefore, the effect of successive "milder" high-strain rate loadings on the pulverization threshold is investigated by applying loading conditions below the initial pulverization threshold. Single and successive loading experiments were performed on quartz-monzonite using a Split Hopkinson Pressure Bar apparatus. Damage-dependent petrophysical properties and elastic moduli were monitored by applying incremental strains. Furthermore, it is shown that the pulverization threshold can be reduced by successive "milder" dynamic loadings from strain rates of ~180 s-1 to ~90 s-1. To do so, it is imperative that the rock experiences dynamic fracturing during the successive loadings prior to pulverization. Combined with loading conditions during an earthquake rupture event, the following generalized fault damage zone structure perpendicular to the fault will develop: furthest from the fault plane, there is a stationary outer boundary that bounds a zone of dynamically fractured rocks. Closer to the fault, a pulverization boundary delimits a band of pulverized rock. Consecutive seismic events will cause progressive broadening of the band of pulverized rocks, eventually creating a wider damage zone observed in mature faults.

  2. Three Dimensional Modeling of Pulverized Coal combustion in a 600MW Corner Fired Boiler

    Institute of Scientific and Technical Information of China (English)

    SandroDal-Secco

    2000-01-01

    The three-dimensional code ESTET developed at the LNH has been used to predict the reactive flow in a 600 W coal fired boiler,Assuming a no-slip condition between the gas and the coal,the equations for a gas-particle mixture can e written.The pulverized coal particle size distribution is represented by a discrete number of particle size groups determined by the measured fineness distrbution.The combustion models taking into account the pyrolysis of the particle and the heterogeneous combustion of char have been validated using intensive measurements performed on the 600MW utility boiler.Heat fluxes were measured along the walls of the furnace and satisfactory agreement between computation and measurements has been achieved in terms of maximum flux location and heat flux intensity.Local measurements of velocities using LDV probe.gas temperature and gas species concentrations were performed in the vicinity of one burner and compared with the computed variables.Again we have observed a good agreement between the computations and the measurements in terms of jet penetration,temperature distribution.oxygen concentration and ash content.

  3. Effective identification of the three particle modes generated during pulverized coal combustion

    Institute of Scientific and Technical Information of China (English)

    YU DunXi; XU MingHou; YAO Hong; LIU XiaoWei; ZHOU Ke

    2008-01-01

    Based on the mass fraction size distribution of aluminum (AI), an improved method for effectively identifying the modes of particulate matter from pulverized coal combustion is proposed in this study. It is found that the particle size distributions of coal-derived particulate matter actually have three modes, rather than just mere two. The ultrafine mode is mainly generated through the vaporization and condensation processes. The coarse mode is primarily formed by the coalescence of molten minerals, while the newly-found central mode is attributed to the heterogeneous condensation or adsorption of vaporized species on fine residual ash particles. The detailed investigation of the mass fraction size distribution of sulfur (S) further demonstrates the rationality and effectiveness of the mass fraction size distribution of the AI in identifying three particle modes. The results show that not only can the number of particle modes be identified in the mass fraction size distributions of the AI but also can their size boundaries be more accurately defined. This method provides new insights in elucidating particle formation mechanisms and their physico-chemical characteristics.

  4. Stabilization of pulverized coal combustion by plasma assist

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, M.; Maruta, K.; Takeda, K.; Solonenko, O.P.; Sakashita, M.; Nakamura, M. [Akita Prefectural University, Akita (Japan). Faculty of System Science & Technology

    2002-03-01

    Ignition and stabilization of pulverized coal combustion by plasma assist is investigated with a 10 kW plasma torch for three different kinds of coal, such as high, medium and low volatile matter coals. Not only high volatile matter coal but also low quality coal can be successfully burned with plasma assist. Research for volatile component of coal shows that a higher temperature field is necessary to extract the volatile matter from inferior coal, while their compositions are almost the same.

  5. Modeling of Pulverized Coal Combustion in Cement Rotary Kiln

    OpenAIRE

    2006-01-01

    In this paper, based on analysis of the chemical and physical processes of clinker formation, a heat flux function was introduced to take account of the thermal effect of clinker formation. Combining the models of gas-solid flow, heat and mass transfer, and pulverized coal combustion, a set of mathematical models for a full-scale cement rotary kiln were established. In terms of commercial CFD code (FLUENT), the distributions of gas velocity, gas temperature, and gas components in a cement rot...

  6. Development of automobile brake lining using pulverized cow hooves

    Directory of Open Access Journals (Sweden)

    Katsina C. BALA

    2016-06-01

    Full Text Available Asbestos has been used for so long as automobile brake lining material because of its good physical and chemical properties. However, due to the health hazard associated with its handling, it has lost favour and several alternative materials are being increasingly used. Asbestos-free brake lining was developed in this work using pulverized cow hooves along with epoxy resin, barium sulphate, graphite and aluminium oxide. This was with a view to exploiting the characteristics of cow hooves, which are largely discarded as waste materials to replace asbestos which has been found to be carcinogenic. Samples of brake linings were produced using compressive moulding in which the physical and mechanical properties of the samples were studied. The results obtained showed that proper bonding was achieved as the percentage by weight of epoxy resin increased and percentage by weight of pulverized cow hooves decreased. The hardness, compressive strength, coefficient of friction, water and oil absorption, relative density and wear rate of the brake linings were determined and compared with existing brake lining properties. The result indicates that pulverized cow hooves can be used as brake lining material for automobiles.

  7. Chemical and toxicological characterization of organic constituents in fluidized-bed and pulverized coal combustion: a topical report

    Energy Technology Data Exchange (ETDEWEB)

    Chess, E.K.; Later, D.W.; Wilson, B.W.; Harris, W.R.; Remsen, J.F.

    1984-04-01

    Coal combustion fly ash from both conventional pulverized coal combustion (PCC) and fluidized-bed combustion (FBC) have been characterized as to their organic constituents and microbial mutagenic activity. The PCC fly ash was collected from a commercial utility generating plant using a low sulfur coal. The FBC fly ash was from a bench-scale developmental unit at the Grand Forks Energy Technology Center. Bulk samples of each fly ash were extracted using benzene/methanol and further separated using high performance liquid chromatography (HPLC). Subfractions from the HPLC separation were analyzed by gas chromatography using both element-specific nitrogen-phosphorus detectors and flame ionization detectors. Microbial mutagenicity assay results indicated that the crude organic extracts were mutagenic, and that both the specific activity and the overall activity of the PCC material was greater than that of the FBC material. Comparison of results from assays using S. typhimurium, TA1538NR indicated that nitrated polycyclic aromatic compounds (PAC) were responsible for much of the mutagenic activity of the PCC material. Similar results were obtained for assays of the FBC organic extract with standard and nitroreductase-deficient strains of S. typhimurium, TA100 and TA1538. Mutagenically active HPLC fractions were analyzed using high resolution gas chromatography (HRGC) and GC mass spectrometry (GC/MS), as well as probe inlet low and high resolutions MS. The discovery and identification of nitrated, oxygenated PAC are important because the presence of both nitro and/or keto functionalities on certain PAC has been shown to confer or enhance mutagenic activity.

  8. Oxy-fuel combustion of solid fuels

    DEFF Research Database (Denmark)

    Toftegaard, Maja Bøg; Brix, Jacob; Jensen, Peter Arendt

    2010-01-01

    Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO2 from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame...... temperature. The flue gas produced thus consists primarily of carbon dioxide and water. Much research on the different aspects of an oxy-fuel power plant has been performed during the last decade. Focus has mainly been on retrofits of existing pulverized-coal-fired power plant units. Green-field plants which...... provide additional options for improvement of process economics are however likewise investigated. Of particular interest is the change of the combustion process induced by the exchange of carbon dioxide and water vapor for nitrogen as diluent. This paper reviews the published knowledge on the oxy-fuel...

  9. Applied investigation on the interaction of hazardous elements binding on ultrafine and nanoparticles in Chinese anthracite-derived fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis F.O., E-mail: lfsoliveira@univates.br [Centro Universitario Univates, Programa de Pos Graduacao Ambiente e Desenvolvimento, Rua Avelino Tallini, 171, Universitario, 95900-000 Lajeado, RS (Brazil); Environmental Science and Nanotechnology Department, Catarinense Institute of Environmental Research and Human Development - IPADHC, Capivari de Baixo, Santa Catarina (Brazil); Jasper, Andre [Centro Universitario Univates, Programa de Pos Graduacao Ambiente e Desenvolvimento, Rua Avelino Tallini, 171, Universitario, 95900-000 Lajeado, RS (Brazil); Andrade, Maria L. [Department of Plant Biology and Soil Science, University of Vigo, 36310 Vigo (Spain); Sampaio, Carlos H. [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Goncalves, 9500, Bairro Agronomia, CEP: 91501-970, Porto Alegre, RS (Brazil); Dai, Shifeng; Li, Xiao; Li, Tian; Chen, Weimei; Wang, Xibo; Liu, Huidong; Zhao, Lixin [China University of Mining and Technology, Beijing (China); Hopps, Shelley G.; Jewell, Robert F. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Hower, James C., E-mail: james.hower@uky.edu [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States)

    2012-03-01

    A multifaceted instrumental approach was employed to determine the chemistry and mineralogy of pulverized-coal-combustion fly ashes from two Chinese power plants. Techniques included traditional optical microscopy, X-ray diffraction, and chemical analysis along with a variety of electron beam methods. The aim is to demonstrate and bring together the wide variety of procedures dealing with F as the key element of concern, and determining its location in the mineral nanoparticles. The Hg content of the Anwen (Songzao coalfield) fly ashes is higher than that of the Diandong (East Yunnan) fly ashes, possibly owing to the greater C and Cl in the Anwen fly ashes. Both fly ash sources contain a variety of amorphous and nano-crystalline trace-element-bearing particles, both associated with multi-walled carbon nanotubes and as particles independent of carbons.

  10. The effect of fuel form on trace element emissions in an industrial-scale coal fired boiler

    Energy Technology Data Exchange (ETDEWEB)

    Miller, S.F.; Wincek, R.T.; Miller, B.G.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States). Coal Utilization Lab.

    1998-12-31

    Eleven of the fourteen inorganic hazardous air pollutants identified in Title 3 of the Clean Air Act Amendments of 1990 are present in the flue gas of pulverized coal-fired boilers. The designated elements include: antimony (Sb), beryllium (Be), chlorine (Cl), cobalt (Co), manganese (Mn), nickel (Ni), selenium (Se), fluorine (F), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and phosphorus (P). Determining the risk of these elements in the environment is difficult at best. However, regulating their emission into the environment has some scientific basis and merit. Approximately 137.5 tons of mercury were emitted in the US by combustion sources in 1994--1995, with coal-fired utility boilers accounting for 37.4% (or 51.6 tons) of the total. Control of trace element emissions from coal-fired utility boilers requires an understanding of the manner in which they occur in coal, their behavior during and after combustion and their form in the stack gas. The multimedia behavior of trace elements during combustion can be traced to their volatility within the combustion and post-combustion environment. The temperature distribution within the combustion system, the mechanism of char and ash formation (e.g. duration of char burnout and char and cenosphere morphology) and the combustion efficiency determine the partitioning of trace elements during combustion. These factors can be affected by the form in which a fuel is fired, e.g., pulverized coal (PC) versus coal-water slurry fuel (CWSF). This paper presents preliminary results of emissions testing aimed at determining the effect of fuel form on the penetration and partitioning of trace elements in an industrial-scale boiler. The tests were conducted on a 2 MMBtu/hr research boiler, in which Middle Kittanning Seam coal (hvA bituminous) from Jefferson County, Pennsylvania was burned in pulverized form and as a CWSF. The tests were conducted in accordance with the procedure outlined in EPA Methods 5 and 29

  11. Utilization Of Rice Husk Ash

    Directory of Open Access Journals (Sweden)

    S. D. Nagrale

    2012-07-01

    Full Text Available India is a major rice producing country, and the husk generated during milling is mostly used as a fuel in the boilers for processing paddy, producing energy through direct combustion and / or by gasification. About 20 million tones of Rice Husk Ash (RHA is produced annually. This RHA is a great environment threat causing damage to the land and the surrounding area in which it is dumped. Lots of ways are being thought of for disposing them by making commercial use of this RHA. RHA can be used as a replacement for concrete (15 to 25%.This paper evaluates how different contents of Rice Husk Ash added to concrete may influence its physical and mechanical properties. Sample Cubes were tested with different percentage of RHA and different w/c ratio, replacing in mass the cement. Properties like Compressive strength, Water absorption and Slump retention were evaluated.

  12. Thermodynamic Characteristics and Economic Analysis of a BFG/Pulverized Coal Mixed Combustion Boiler%300MW高炉煤气与煤粉混燃锅炉热力特性及经济性分析

    Institute of Scientific and Technical Information of China (English)

    王春波; 魏建国; 黄江城

    2012-01-01

    针对高炉煤气与煤粉混燃易发生过(再)热器超温、飞灰含碳量高等问题,对某300MW机组四角切圆高炉煤气/煤粉混燃锅炉进行了热力特性计算,并对掺烧高炉煤气后机组的经济性进行了分析.结果表明:掺烧高炉煤气后炉内温度降低,烟气量增加,辐射吸热量减少而对流吸热量增加,炉膛出口烟温及其后受热面区域的烟温升高,排烟温度升高,锅炉效率降低;掺烧高炉煤气后厂用电率有所升高,但发电煤耗降低,使发电成本降低.%To solve the problems occurring in a 300 MW tangential blast furnace gas (BFG)/pulverized coal blended combustion boiler, such as overheating of its superheater/reheater and high carbon content in the fly ash, etc. , thermodynamic calculations and an economic analysis were carried out. Results show that af- ter the fuel coal is blended with BFG, the in-furnace temperature drops, the exhaust gas volume rises, the absorption of radiation heat reduces, the absorption of convection heat increases, the gas temperatures at and after furnace outlet rise, the exhaust gas temperature increases and the boiler efficiency decreases; af- ter mixing with BFG, the house power consumption rises, but the coal consumption for power generation reduces, which helps to reduce the power generating cost.

  13. Comparative study of semi-industrial-scale flames of pulverized coals and biomass

    Energy Technology Data Exchange (ETDEWEB)

    Ballester, J.; Barroso, J.; Cerecedo, L.M.; Ichaso, R. [University of Zaragoza, Zaragoza (Spain)

    2005-05-01

    Three p.f. flames have been studied in a semi-industrial furnace, using different fuels: a bituminous coal, a lignite, and a biomass (oak sawdust). The operating conditions were exactly the same for the two coals, and very similar to those for the biornass flame. The objective was to evaluate the impact of differences in fuel composition on flame characteristics, through measurement of the spatial distribution of the main parameters: temperature and concentrations of O{sub 2}, CO, NOx, unburnt hydrocarbons, and N{sub 2}O. The higher volatiles content in the lignite leads to higher temperatures and more intense combustion than the bituminous coal. Nevertheless, as might be expected, more marked differences are observed between the flames from the biomass and coals. The much higher volatiles content of the wood results in a more intense flame close to the burner, as indicated by visual observations and by concentrations of unburnt gases (CO and unburnt hydrocarbons) in that zone. It is remarkable that the combustion zone extends further for the biomass; while unburnt species were very low for the coals at an axial distance of 1 m, high values were detected for the pulverized oak. The measurements suggest that two stages can be distinguished in the biomass flame: a zone of intense combustion close to the burner, followed by a second region where the large biomass particles gradually devolatilize and are consumed.

  14. [Ash Meadows Purchase Proposal

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A proposal sent to the Richard King Mellon Foundation for a loan to fund the purchase of Ash Meadows by the Nature Conservancy. Ash Meadows, set outside of Las Vegas...

  15. STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Eric Suuberg; John Veranth; Xu Chen

    2003-05-20

    The overall objective of the present project is to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific research issues to be addressed include: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity; and (3) the kinetics and mechanism of ash ozonation. This data will provide scientific and engineering support of the ongoing process development activities. During this fourth project period we completed the characterization of ozone-treated carbon surfaces and wrote a comprehensive report on the mechanism through which ozone suppresses the adsorption of concrete surfactants.

  16. STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Eric Suuberg; John Veranth; Xu Chen

    2002-09-10

    The overall objective of the present project is to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific research issues to be addressed include: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity; and (3) the kinetics and mechanism of ash ozonation. This data will provide scientific and engineering support of the ongoing process development activities. During this fourth project period we completed the characterization of ozone-treated carbon surfaces and wrote a comprehensive report on the mechanism through which ozone suppresses the adsorption of concrete surfactants.

  17. Sulphation characteristics of paper sludge ash

    Energy Technology Data Exchange (ETDEWEB)

    Roh, S.A. [Environmental Systems Research Center, Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of); Kim, S.D. [Environmental Systems Research Center, Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of). Dept. of Chemical and Biomolecular Engineering

    2007-04-15

    Landfills are no longer a viable solution for the disposal of sludge produced from waste water treatment plants because of the decrease in available space, rising fees and growing environmental concerns. However, thermal utilization of this waste may be an economic and sustainable disposal solution. Co-combustion of low heating value sludge with fossil fuels has a positive effect for sulfur dioxide (SO{sub 2}) emissions due to the low sulphur content of biomass fuels and increased sulphur retention in the ash. The sulphur retention is attributed to the formation of sulphates, such as CaSO{sub 4}, K{sub 2}SO{sub 4} and Na{sub 2}SO{sub 4}. The amount of fuel-ash-related sulphur sorption increases during co-combustion. Therefore, sorbents for sulphur reduction may not be required if proper control of the biomass feed is maintained. This paper presented a study in which the sulphation characteristics of calcium-rich paper sludge ash were determined for the use of co-combustion of biomass and coal. The calcium in the paper sludge ash came from the limestone filler used in the manufacturing process to increase the density and whiteness of the paper at 2 paper mills in Korea. A thermobalance reactor along with XRD and SEM-EDX were used for the analysis of sulphated ash to determine the effects of sulphation temperature, particle size and SO{sub 2} concentration on sulphation conversion. The activation energy and pre-exponential factor of sulphation reaction of sludge ash were determined based on the uniform-reaction model. X-ray diffraction analysis revealed that most of the sulphation compounds were CaSO{sub 4}. The sulphation occurred uniformly throughout the ash and the CaSO{sub 4} did not block the outer pore of the sludge ash. The uniform distributions of CaO and other inert minerals in the ash resulted in uniform sulphation with good penetration of SO{sub 2} into pores of the sludge ash without pore blocking during sulphation of CaO. 13 refs., 1 tab., 9 figs.

  18. Nitric oxide formation mechanisms, and their computation in pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Flour, I.; Dal Secco, S.

    1995-10-01

    This report consists of a review of several articles on nitric oxide emissions from coal-fired furnace. Three mechanisms have been identified, depending on the initial nitrogen sources and the composition of specific flame regions: - thermal-NO, formed from molecular nitrogen in the combustion products region at high temperature, - prompt-NO, formed from molecular nitrogen in the oxidation zone, - fuel-NO, formed from the fuel-bound nitrogen, partly during the coal pyrolysis (homogeneous reactions) and partly through reactions on the surface of the particle. In the combustion of pulverized coal, the fuel-NO mechanism accounts for the main source of nitric oxide formed. Detailed schemes of those reactions - when available - are too much complex to be used in tri-dimensional computation of pollutant emissions in furnaces of practical interest. According to the literature, reduced schemes seem to have been applied most frequently. The reaction schemes for the fuel-NO and the prompt-NO are based on the results of De Soete. For the homogeneous reactions, the intermediate species formed is assumed to be mainly HCN, leading to both formation and reduction reactions for NO, depending on the flame region. The formation of nitric oxide from the char-bound nitrogen, through heterogeneous reactions on the surface on the particle, is modelled by assuming the char-bound nitrogen to be released as HCN, with a rate proportional to char combustion. The released char nitrogen then reacts through the same path as the HCN released during pyrolysis. In the thermal-NO mechanism, nitric oxide is formed from molecular nitrogen, through the extended Zeldovich mechanism. This scheme contains radical species (O, N), which concentrations are assumed to be determined from the stationary condition or the equilibrium assumption. However, in spite of the use of reduced schemes for NO formation, the modelling of the important effect of the turbulent fluctuations has to be taken into account.

  19. Combustion characteristics of pulverized coal and air/gas premixed flame in a double swirl combustor

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, M.M. [Ain Shams University, Cairo (Egypt). Faculty of Education

    2009-07-01

    An experimental work was performed to investigate the co-firing of pulverized coal and premixed gas/air streams in a double swirl combustor. The results showed that the NOx emissions are affected by the relative rates of thermal NOx formation and destruction via the pyrolysis of the fuel-N species in high temperature fuel-rich zones. Various burner designs were tested in order to vary the temperature history and the residence time across both coal and gas flames inside the furnace. It was found that by injecting the coal with a gas/air mixture as a combined central jet surrounded by a swirled air stream, a double flame envelope develops with high temperature fuel-rich conditions in between the two reaction zones such that the pyrolysis reactions to N{sub 2} are accelerated. A further reduction in the minimum NOx emissions, as well as in the minimum CO concentrations, was reported for the case where the coal particles are fed with the gas/air mixture in the region between the two swirled air streams. On the other hand, allocating the gas/air mixture around the swirled air-coal combustion zone provides an earlier contact with air and retards the NOx reduction mechanism in such a way that the elevated temperatures around the coal particles allow higher overall NOx emissions. The downstream impingement of opposing air jets was found more efficient than the impinging of particle non-laden premixed flames for effective NOx reduction. In both cases, there is an upstream flow from the stagnation region to the coal primary combustion region, but with the case of air impingement, the hot fuel-rich zone develops earlier. The optimum configuration was found by impinging all jets of air and coal-gas/air mixtures that pronounced minimum NOx and CO concentrations of 310 and 480ppm, respectively.

  20. Probe Measurements of Ash Deposit Formation Rate and Shedding in a Biomass Suspension-Fired boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming;

    The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension-fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share...

  1. Experimental study on the angle of repose of pulverized coal

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Jiansheng Zhang; Shi Yang; Hai Zhang; Hairui Yang; Guangxi Yue

    2010-01-01

    An experimental study on the angle of repose(AoR)of pulverized coal with different particle sizes and different moisture contents(MC)was conducted.Three different measurement methods,free-base piling,fixed-base piling and sliding,were used.The data were analyzed by one-way and two-way analysis of variance.The results showed that the AoRs of pulverized coal with particle sizes smaller than 150 μm were in the range of 30-50°.The characterization of the flowability of pulverized coal was some cohesiveness or true cohesiveness.The increase of MC will increase AoR and thus decrease the flowability of the powder.However,the particle size effect is bifurcated.Below a critical size,the decrease of particle size decreases the flowability; while above the critical size,the decrease of particle size increases the flowability.It was found that the value of the critical size strongly depends on the powder density.Moreover,the AoR dependence on particle size could be linked with the Geldart's particle classification.The critical size at the turning point is on the boundary between Group A and Group B in Geldart's classification diagram.Based on the experimental results,there is no significant cross interaction between particle size and MC.The AoRs measured by free-base method and fixed-base method are close,but both remarkably smaller than that measured by the sliding method.

  2. Characterization of char derived from various types of solid wastes from the standpoint of fuel recovery and pretreatment before landfilling.

    Science.gov (United States)

    Hwang, I H; Matsuto, T; Tanaka, N; Sasaki, Y; Tanaami, K

    2007-01-01

    Carbonization is a kind of pyrolysis process to produce char from organic materials under an inert atmosphere. In this work, chars derived from various solid wastes were characterized from the standpoint of fuel recovery and pretreatment of waste before landfilling. Sixteen kinds of municipal and industrial solid wastes such as residential combustible wastes, non-combustible wastes, bulky wastes, construction and demolition wastes, auto shredder residue, and sludges were carbonized at 500 degrees C for 1h under nitrogen atmosphere. In order to evaluate the quality of char as fuel, proximate analysis and heating value were examined. The composition of raw waste had a significant influence on the quality of produced char. The higher the ratio of woody biomass in waste, the higher heating value of char produced. Moreover, an equation to estimate heating value of char was developed by using the weight fraction of fixed carbon and volatile matter in char. De-ashing and chlorine removal were performed to improve the quality of char. The pulverization and sieving method seems to be effective for separation of incombustibles such as metal rather than ash. Most char met a 0.5 wt% chlorine criterion for utilization as fuel in a shaft blast furnace after it was subjected to repeated water-washing. Carbonization could remove a considerable amount of organic matter from raw waste. In addition, the leaching of heavy metals such as chrome, cadmium, and lead appears to be significantly suppressed by carbonization regardless of the type of raw waste. From these results, carbonization could be considered as a pretreatment method for waste before landfilling, as well as for fuel recovery.

  3. A new approach to study fast pyrolysis of pulverized coal

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Yao, J.; Lin, W. [Chinese Academy of Sciences, Institute of Chemical Metallurgy Fast Reactions Laboratory, Beijing, BJ (China)

    2002-07-01

    An experimental study of the effects of varying bed temperature and coal particle size on the fast pyrolysis of pulverized coal in a downer reactor is described. A Datong bituminous coal (particle size 0.5 and 0.34 mm) was studied at temperatures ranging from 592{sup o} C to 720{sup o} C. The experiments were conducted in a batch apparatus. An on-line gas analyzer was used to measure carbon dioxide release curves. The experimental data were used to develop a pyrolysis model that quantifies the fast heating of fine coal particles. 14 refs., 4 figs., 2 tabs.

  4. Amphiphilic semi-interpenetrating polymer networks using pulverized rubber

    Science.gov (United States)

    Shahidi, Nima

    Scrap rubber materials provide a significant challenge to either reuse or safe disposal. Every year, millions of tires are discarded to landfills in the United States, consuming a staggering amount of land space, creating a high risk for large fires, breeding mosquitoes that spread diseases, and wasting the planet's natural resources. This situation cannot be sustained. The challenge of reusing scrap rubber materials is mainly due to the crosslinked structure of vulcanized rubber that prevent them from melting and further processing for reuse. The most feasible recycling approach is believed to be a process in which the vulcanized rubber is first pulverized into a fine powder and then incorporated into new products. The production of fine rubber particles is generally accomplished through the use of a cryogenic process that is costly. Therefore, development of a cost effective technology that utilizes a large quantity of the scrap rubber materials to produce high value added materials is an essential element in maintaining a sustainable solution to rubber recycling. In this research, a cost effective pulverization process, solid state shear extrusion (SSSE), was modified and used for continuous pulverization of the rubber into fine particles. In the modified SSSE process, pulverization takes place at high compressive shear forces and a controlled temperature. Furthermore, an innovative particle modification process was developed to enhance the chemical structure and surface properties of the rubber particles for manufacturing of high value added products. Modification of rubber particles was accomplished through the polymerization of a hydrophilic monomer mixture within the intermolecular structure of the hydrophobic rubber particles. The resulting composite particles are considered as amphiphilic particulate phase semi-interpenetrating polymer networks (PPSIPNs). The modified rubber particles are water dispersible and suitable for use in a variety of aqueous media

  5. Properties of concrete modified with waste Low Density Polyethylene and saw dust ash

    Science.gov (United States)

    Srimanikandan, P.; Sreenath, S.

    2017-07-01

    The increase in industrialization creates need for disposal of large quantity of by-products. To overcome the difficulty of disposal, these by-products can be used as a replacement for raw material. In this concern, non-conventional industrial wastes such as plastic bags, PET bottles, pulverized waste Low Density Polyethylene (LDPE) and biological waste such as saw-dust ash, coconut coir were used as a replacement in concrete. In this project, saw-dust ash and pulverized waste LDPE were introduced as the partial replacement for cement and fine aggregates respectively. 0%, 5%, 10%, 15% and 20% of sand by volume was replaced with LDPE and 0%, 1%, 3%, 5% and 10% of cement by volume was replaced with saw dust ash. Standard cube, cylinder and prism specimens were cast to assess the compressive strength, split tensile strength and flexural strength of modified concrete after 28 days of curing. Optimum percentage of replacement was found by comparing the test results. The mix with 5% of LDPE and 3% of saw dust ash showed a better result among the other mixes.

  6. Water Diffusion Modelling of CFB Fly Ash Thermoset Composite

    Directory of Open Access Journals (Sweden)

    Villa Ralph P.

    2016-01-01

    Full Text Available The shift in coal-fired power plants from pulverized coal (PC boiler technology into the greener circulating fluidized bed (CFB boiler technology resulted into a major deviation in the properties of the waste fly ash generated making it less suitable for its previous application as additives for construction materials. A new market for CFB fly ash had to be found for it not to end up as a zero value by-product. Using CFB fly ash as filler for thermoset composites is a new and remarkable application. Only a few studies, however, have been done to characterize the properties of this new material. Further experimentation and analysis may be costly and time-consuming since common procedures are material destructive. A computer-aided modeling of the composite’s water sorption behavior was done. The effect of particle loading, size and shape were considered. These properties were varied and the resulting overall diffusivities were compared to previous experimental studies. The comparison of the model and experimental diffusivity values showed satisfactory results. This model may then provide a cheaper and more time-efficient method for the characterization of the water sorption properties of CFB fly ash thermoset composites. In the future, this may lead to further studies on its application as a green material.

  7. Pulverized coal injection on the blast furnaces at U.S. Steel Kosice, S.R.O.

    Energy Technology Data Exchange (ETDEWEB)

    Baran, P.; McCoy, M.; Szalona, T. [United States Steel Corp., Kosice (Slovakia)

    2008-07-01

    United States Steel Corporation at Kosice built a new modern PCI facility that meets environmental criteria and provides a replacement for financially demanding metallurgical coke with a less expensive pulverized coal. The pulverized coal injection (PCI) technology was applied to blast furnaces no. 2 and 3 in 1993 and has resulted in the following improvements: production has increased an average of 400 to 500 tons/day; pig iron production economics have improved not only because of replacing the metallurgical coke with PCI, but also due to a decrease in the total fuel rate for producing 1 ton of hot metal; blast furnace gas utilization increased with ETA CO values around 48 per cent; and the blast furnace operation is more stable by regular burden descend. The most distinguished change has been in the way raw materials are charged to the furnaces. This paper outlined the coal quality requirements for PCI and presented a basic technological description of PCI preparation. The operational experience of the 2 blast furnaces were presented for the period of 2000 to 2007. Recommendations for PCI rate increase were also presented. It was concluded that using PCI technology in blast furnace no. 1 may bring the greatest economic efficiency for United Steel Corporation at Kosice. 4 refs., 2 tabs., 8 figs.

  8. Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Peter Y. [National Energy Technology Lab. (NETL), Albany, OR (United States); Kwong, Kyei-Sing [National Energy Technology Lab. (NETL), Albany, OR (United States); Bennett, James [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2015-09-27

    Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. Here, we measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and their ash fusion temperatures through optical image analysis. We made all measurements in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. Finally, an understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.

  9. An investigation on polycyclic aromatic hydrocarbon emissions from pulverized coal combustion systems

    Science.gov (United States)

    Pisupati; Wasco; Scaroni

    2000-05-29

    Results from a series of tests conducted to study the emission of polynuclear or polycyclic aromatic hydrocarbons (PAHs) from bench-scale and small industrial, water-tube boiler are discussed. A Middle Kittanning, and Upper Freeport seam coals were used in the study. Samples were extracted from the reactor outlet and from the inlet and outlet sides of the research boiler's (RB) baghouse using EPA promulgated methods.Only acenaphthene and fluoranthene were detected in down-fired combustor (DFC) samples. In addition to these two, naphthalene was detected in the RB samples. Emission factors ranged from 80 to 320 &mgr;g/kg of fuel fired. Although there were minor trends in the emissions' data, given the reproducibility limits for PAH compounds, no significant differences were found in the emissions with respect to the fuel type or form (pulverized coal (PC) vs. coal-water slurry fuel (CWSF), and raw vs. cleaned coal) and firing conditions (high and low excess air). The PAH emissions showed a decrease with increase in the firing rate.A bench-scale drop-tube reactor (DTR) was used to study the effects of temperature and residence time on PAH formation. The results revealed near constant PAH concentrations in the solid-phase samples, while the PAH concentrations in the vapor-phase samples increased as a function of temperature. At a temperature of around 1300 degrees C, the rate of PAH formation was exceeded by the rate of PAH oxidation, and PAH concentrations in the vapor phase began to decrease.

  10. Fuel nitrogen conversion in solid fuel fired systems

    Energy Technology Data Exchange (ETDEWEB)

    P. Glarborg; A.D. Jensen; J.E. Johnsson [Technical University of Denmark, Lyngby (Denmark). Department of Chemical Engineering

    2003-07-01

    Understanding of the chemical and physical processes that govern formation and destruction of nitrogen oxides (NOx) in combustion of solid fuels continues to be a challenge. There are still unresolved issues that may limit the potential of primary measures for NOx control. In most solid fuel fired systems oxidation of fuel-bound nitrogen constitutes the dominating source of nitrogen oxides. The paper reviews some fundamental aspects of fuel nitrogen conversion in these systems, emphasizing combustion of coal since most previous work deal with this fuel. Results on biomass combustion are also discussed. Homogeneous and heterogeneous pathways in fuel NO formation and destruction are discussed and the effect of fuel characteristics, devolatilization conditions and combustion mode on the oxidation selectivity towards NO and N{sub 2} is evaluated. Results indicate that even under idealized conditions, such as a laminar pulverized-fuel flame, the governing mechanisms for fuel nitrogen conversion are not completely understood. Light gases, tar, char and soot may all be important vehicles for fuel-N conversion, with their relative importance depending on fuel rank and reaction conditions. Oxygen availability and fuel-nitrogen level are major parameters determining the oxidation selectivity of fuel-N towards NO and N{sub 2}, but also the ability of char and soot to reduce NO is potentially important. The impact of fuel/oxidizer mixing pattern on NO formation appears to be less important in solid-fuel flames than in homogeneous flames. 247 refs., 14 figs., 2 tabs.

  11. Effect of multiphase radiation on coal combustion in a pulverized coal jet flame

    Science.gov (United States)

    Wu, Bifen; Roy, Somesh P.; Zhao, Xinyu; Modest, Michael F.

    2017-08-01

    The accurate modeling of coal combustion requires detailed radiative heat transfer models for both gaseous combustion products and solid coal particles. A multiphase Monte Carlo ray tracing (MCRT) radiation solver is developed in this work to simulate a laboratory-scale pulverized coal flame. The MCRT solver considers radiative interactions between coal particles and three major combustion products (CO2, H2O, and CO). A line-by-line spectral database for the gas phase and a size-dependent nongray correlation for the solid phase are employed to account for the nongray effects. The flame structure is significantly altered by considering nongray radiation and the lift-off height of the flame increases by approximately 35%, compared to the simulation without radiation. Radiation is also found to affect the evolution of coal particles considerably as it takes over as the dominant mode of heat transfer for medium-to-large coal particles downstream of the flame. To investigate the respective effects of spectral models for the gas and solid phases, a Planck-mean-based gray gas model and a size-independent gray particle model are applied in a frozen-field analysis of a steady-state snapshot of the flame. The gray gas approximation considerably underestimates the radiative source terms for both the gas phase and the solid phase. The gray coal approximation also leads to under-prediction of the particle emission and absorption. However, the level of under-prediction is not as significant as that resulting from the employment of the gray gas model. Finally, the effect of the spectral property of ash on radiation is also investigated and found to be insignificant for the present target flame.

  12. Fly ash carbon passivation

    Science.gov (United States)

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  13. Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus

    Science.gov (United States)

    2014-01-01

    This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and

  14. Numerical simulation of the influence of stationary louver and coal particle size on distribution of pulverized coal to the feed ducts of a power plant burner

    Directory of Open Access Journals (Sweden)

    Živković Goran

    2009-01-01

    Full Text Available One of the key requirements related to successful utilization of plasma technology as an oil-free backup system for coal ignition and combustion stabilization in power plant boilers is provision of properly regulated pulverized coal distribution to the feed ducts leading the fuel mixture to a burner. Proper regulation of coal distribution is deemed essential for achieving an adequate pulverized coal concentration in the zone where thermal plasma is being introduced. The said can be efficiently achieved by installation of stationary louver in the coal-air mixing duct ahead of the feed ducts of a burner. The paper addresses numerical simulation of a two-phase flow of air-pulverized coal mixture in the mixing ducts, analyzing the effects of particle size distribution on pulverized coal distribution to the burner feed ducts. Numerical simulation was performed using the FLUENT 6.3 commercial code and related poly-dispersed flow module, based on the PSI-CELL approach. Numerical experiments have been performed assuming a mono-dispersed solid phase with particle diameter ranging from 45 mm to 1200 mm. Distance between the louver blades and the resulting effect on the flow profile was analyzed as well. Results obtained indicate that the size of coal particles considerably influence the overall solid phase distribution. While fine particles, with diameters at the lower end of the above specified range, almost fully follow the streamlines of the continuous phase, coarser particles, which hit the louver blades, deflect towards the thermal plasma zone. In this manner, a desired phase concentration in the considered zone can be reached. For the said reason, installation of stationary louver have been deemed a very efficient way to induce phase separation, primarily due to more pronounced impact of the installed louver on discrete phase flow then the impact on the flow of the continuous phase.

  15. Combustion and economics of coal slurry fuels: a look at coal-fuel oil slurries

    Energy Technology Data Exchange (ETDEWEB)

    Murayama, T.; Matsuoka, H.

    1984-01-01

    With the aim of reducing dependence on petroleum, research has been going ahead into the development of various alternative fuels. Of these, coal slurry fuels are regarded as being first in line for commercialization. The authors discuss the combustion of coal-oil fuels. The combustion of fuel oil, pulverized coal and coal-water slurry is also examined. In each case, combustion properties and associated problems are discussed. Finally, the economics of these fuels are examined and trends in research and development surveyed. 23 references.

  16. Testing exposure of a jet engine to a dilute volcanic-ash cloud

    Science.gov (United States)

    Guffanti, M.; Mastin, L. G.; Schneider, D. J.; Holliday, C. R.; Murray, J. J.

    2013-12-01

    An experiment to test the effects of volcanic-ash ingestion by a jet engine is being planned for 2014 by a consortium of U.S. Government agencies and engine manufacturers, under the auspices of NASA's Vehicle Integrated Propulsion Research Program. The experiment, using a 757-type engine, will be an on-ground, on-wing test carried out at Edwards Air Force Base, California. The experiment will involve the use of advanced jet-engine sensor technology for detecting and diagnosing engine health. A primary test objective is to determine the effect on the engine of many hours of exposure to ash concentrations (1 and 10 mg/cu m) representative of ash clouds many 100's to >1000 km from a volcanic source, an aviation environment of great interest since the 2010 Eyjafjallajökull, Iceland, eruption. A natural volcanic ash will be used; candidate sources are being evaluated. Data from previous ash/aircraft encounters, as well as published airborne measurements of the Eyjafjallajökull ash cloud, suggest the ash used should be composed primarily of glassy particles of andesitic to rhyolitic composition (SiO2 of 57-77%), with some mineral crystals, and a few tens of microns in size. Collected ash will be commercially processed less than 63 microns in size with the expectation that the ash particles will be further pulverized to smaller sizes in the engine during the test. For a nominally planned 80 hour test at multiple ash-concentration levels, the test will require roughly 500 kg of processed (appropriately sized) ash to be introduced into the engine core. Although volcanic ash clouds commonly contain volcanic gases such as sulfur dioxide, testing will not include volcanic gas or aerosol interactions as these present complex processes beyond the scope of the planned experiment. The viscous behavior of ash particles in the engine is a key issue in the experiment. The small glassy ash particles are expected to soften in the engine's hot combustion chamber, then stick to cooler

  17. Application of the NOx Reaction Model for Development of Low-NOx Combustion Technology for Pulverized Coals by Using the Gas Phase Stoichiometric Ratio Index

    Directory of Open Access Journals (Sweden)

    Kenji Yamamoto

    2011-03-01

    Full Text Available We previously proposed the gas phase stoichiometric ratio (SRgas as an index to evaluate NOx concentration in fuel-rich flames. The SRgas index was defined as the amount of fuel required for stoichiometric combustion/amount of gasified fuel, where the amount of gasified fuel was the amount of fuel which had been released to the gas phase by pyrolysis, oxidation and gasification reactions. In the present study we found that SRgas was a good index to consider the gas phase reaction mechanism in fuel-rich pulverized coal flames. When SRgas < 1.0, NOx concentration was strongly influenced by the SRgas value. NOx concentration was also calculated by using a reaction model. The model was verified for various coals, particle diameters, reaction times, and initial oxygen concentrations. The most important reactions were gas phase NOx reduction reactions by hydrocarbons. The hydrocarbon concentration was estimated based on SRgas. We also investigated the ratio as an index to develop a new low-NOx combustion technology for pulverized coals. We examined the relation between local SRgas distribution in the fuel-rich region in the low-NOx flame and NOx emissions at the furnace exit, by varying burner structures. The relationship between local SRgas value and local NOx concentration was also examined. When a low-NOx type burner was used, the value of SRgas in the flame was readily decreased. When the local SRgas value was the same, it was difficult to influence the local NOx concentration by changing the burner structure. For staged combustion, the most important item was to design the burner structure and arrangement so that SRgas could be lowered as much as possible just before mixing with staged air.

  18. Regular Recycling of Wood Ash to Prevent Waste Production (RecAsh). Technical Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Lars E-mail: lars.t.andersson@skogsstyreslen.se

    2007-03-15

    At present, the extraction of harvest residues is predicted to increase in Sweden and Finland. As an effect of the intensified harvesting, the export of nutrients and acid buffering substances from the growth site is also increased. Wood ash could be used to compensate forest soils for such losses. Most wood fuel ash is today often deposited in landfills. If the wood ash is recycled, wood energy is produced without any significant waste production. Ash recycling would therefore contribute to decreasing the production of waste, and to maintaining the chemical quality of forest waters and biological productivity of forest soils in the long term. The project has developed, analysed and demonstrated two regular ash-recycling systems. It has also distributed knowledge gathered about motives for ash recycling as well as technical and administrative solutions through a range of media (handbooks, workshops, field demonstrations, reports, web page and information videos). Hopefully, the project will contribute to decreasing waste problems related to bio-energy production in the EU at large. The project has been organised as a separate structure at the beneficiary and divided in four geographically defined subprojects, one in Finland and three in Sweden (Central Sweden, Northern Sweden, and South-western Sweden). The work in each subproject has been lead by a subproject leader. Each subproject has organised a regional reference group. A project steering committee has been established consisting of senior officials from all concerned partners. The project had nine main tasks with the following main expected deliverables and output: 1. Development of two complete full-scale ash-recycling systems; 2. Production of handbooks of the ash recycling system; 3. Ash classification study to support national actions for recommendations; 4. Organise regional demonstrations of various technical options for ash treatment and spreading; 5. Organise national seminars and demonstrations of

  19. Assessment against Experiments of Devolatilization and Char Burnout Models for the Simulation of an Aerodynamically Staged Swirled Low-NOx Pulverized Coal Burner

    Directory of Open Access Journals (Sweden)

    Marco Torresi

    2017-01-01

    Full Text Available In the next few years, even though there will be a continuous growth of renewables and a loss of the share of fossil fuel, energy production will still be strongly dependent on fossil fuels. It is expected that coal will continue to play an important role as a primary energy source in the next few decades due to its lower cost and higher availability with respect to other fossil fuels. However, in order to improve the sustainability of energy production from fossil fuels, in terms of pollutant emissions and energy efficiency, the development of advanced investigation tools is crucial. In particular, computational fluid dynamics (CFD simulations are needed in order to support the design process of low emission burners. Even if in the literature several combustion models can be found, the assessment of their performance against detailed experimental measurements on full-scale pulverized coal burners is lacking. In this paper, the numerical simulation of a full-scale low-NO x , aerodynamically-staged, pulverized coal burner for electric utilities tested in the 48 MW th plant at the Combustion Environment Research Centre (CCA - Centro Combustione e Ambiente of Ansaldo Caldaie S.p.A. in Gioia del Colle (Italy is presented. In particular, this paper is focused on both devolatilization and char burnout models. The parameters of each model have been set according to the coal characteristics without any tuning based on the experimental data. Thanks to a detailed description of the complex geometry of the actual industrial burner and, in particular, of the pulverized coal inlet distribution (considering the entire primary air duct, in order to avoid any unrealistic assumption, a correct selection of both devolatilization and char burnout models and a selection of suited parameters for the NO x modeling, accurate results have been obtained in terms of NO x formation. Since the model parameters have been evaluated a priori, the numerical approach proposed

  20. Industrial Experimental Study and Application of Plasma Pulverized Coal Ignition Burner%等离子煤粉点火燃烧器工业性试验研究及应用

    Institute of Scientific and Technical Information of China (English)

    崔凤誉; 张玉周

    2001-01-01

    This paper systematically explains the content and method of industrial experiment in plasma pulverized coal ignition burner analyzes the experiment results,and puts forward the two-parameter concentration of pulverized coal and fuel ratio combustion regulation-control of plasma pulverized coal ignition burner.On the basis of the industrial experiment,Shandong Yantai Coal-fired Power Plant has realized successfully the boiler ignition without oil aid by using plasma pulverized coal ignition burner for the first time.%阐释等离子煤粉点火燃烧器工业试验的内容及方法,并对其试验结果进行分析。提出等离子煤粉点火燃烧器燃烧调整的双参数煤粉浓度、燃功比控制法。在对等离子煤粉点火燃烧器工业试验基础上,2000年2月15日,山东烟台发电厂利用等离子煤粉点火燃烧器首次实现了机组无油点火。

  1. EVALUATION OF BIOMSS AND COAL SLURRIES AS FUEL-LEAN REBURN FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Vijay K. Sethi

    2006-11-06

    Breen Energy Solutions (BES) and Western Research Institute (WRI) tested biomass and coal slurries and other carbonaceous substances such as fuel oil/water emulsions as NO{sub x} reburn fuel in the combustion test facility (CTF). The overall goal of the project was to determine the NO{sub x} reduction potential of various biomass and coal reburn fuels, and to identify the optimum conditions for NO{sub x} control. Specific objectives were to inject biomass, biosolids, coal, biomass/coal, and biosolids/coal slurries into the upper furnace of CTF and determine the resulting NO{sub x} reductions and CO emissions, to identify optimum injection rates and injection locations for these reburn fuels, and to install a reaction zone stabilizer device in CTF and determine its effectiveness in reducing CO and further reducing NO{sub x}. Combustion tests achieved 40% to 60% NO{sub x} reductions with 10% to 20% reburn fuel heat input. The project has demonstrated the technical feasibility of in-situ gasification of slurries including pulverized coal and 75% pulverized coal/25% biosolids by weight, and the ability to utilize the gasification products as NO{sub x} reburn fuel. This work also demonstrated that pulverized coal/water slurries can be successfully gasified and used as reburn fuels, and there is no need for use of micronized coal. Very good burnout of the pulverized coal slurry was demonstrated in this work. Similarly, the project has demonstrated the technical feasibility of in-situ gasification of oil/water emulsion and the ability to utilize the associated gasification products as NO{sub x} reburn fuel.

  2. Effect of CO2 gasification reaction on oxycombustion of pulverized coal char.

    Energy Technology Data Exchange (ETDEWEB)

    Molina, Alejandro (Universidad Nacional de Colombia, Medellin, Colombia); Hecht, Ethan S.; Shaddix, Christopher R.; Haynes, Brian S. (University of Sydney, New South Wales, Australia)

    2010-07-01

    For oxy-combustion with flue gas recirculation, as is commonly employed, it is recognized that elevated CO{sub 2} levels affect radiant transport, the heat capacity of the gas, and other gas transport properties. A topic of widespread speculation has concerned the effect of the CO{sub 2} gasification reaction with coal char on the char burning rate. To give clarity to the likely impact of this reaction on the oxy-fuel combustion of pulverized coal char, the Surface Kinetics in Porous Particles (SKIPPY) code was employed for a range of potential CO{sub 2} reaction rates for a high-volatile bituminous coal char particle (130 {micro}m diameter) reacting in several O{sub 2} concentration environments. The effects of boundary layer chemistry are also examined in this analysis. Under oxygen-enriched conditions, boundary layer reactions (converting CO to CO{sub 2}, with concomitant heat release) are shown to increase the char particle temperature and burning rate, while decreasing the O{sub 2} concentration at the particle surface. The CO{sub 2} gasification reaction acts to reduce the char particle temperature (because of the reaction endothermicity) and thereby reduces the rate of char oxidation. Interestingly, the presence of the CO{sub 2} gasification reaction increases the char conversion rate for combustion at low O{sub 2} concentrations, but decreases char conversion for combustion at high O{sub 2} concentrations. These calculations give new insight into the complexity of the effects from the CO{sub 2} gasification reaction and should help improve the understanding of experimentally measured oxy-fuel char combustion and burnout trends in the literature.

  3. Design and manufacture of the dry pulverizing{center_dot}mixing device

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae Hoo; Yoon, Ji Sup; Kim, Young Hwan; Jin, Jae Hyoun [KAERI, Taejon (Korea, Republic of)

    2002-07-01

    The dry pulverizing/mixing device is used to deal with the spent fuels for the safe disposal. The separated pellets from hulls by a slitting device are put and oxidized from UO{sub 2} solid pellet to U{sub 3}O{sub 8} powder in the device. The device have been developed based on a voloxidation method which is one of several dry de-cladding methods. We have benchmarked dry de-cladding methods, analyzed applicability to the advanced spent fuel management process, integrated and compared several configuration, and finally derived detailed specifications proper to requirements for the device. Also, thermal characteristics of the device such as thermal stress and strain have been analyzed by the commercial software, I-DEAS, and the reliability of the results have been verified by the KOLAS(KOrea Laboratory Accreditation Scheme). The UO{sub 2} solid pellets are put in the device which has a capacity of 20 kgHM per a batch, heated up about 600 .deg. C in the air environment. Then, the UO{sub 2} solid pellets are oxidized into the U{sub 3}O{sub 8} powder, and the powder is collected in a special vessel. The device has been designed and developed as follows: the multi-staged fine hole meshes are used to reduce the size of the powder gradually, heat and air(oxygen) are supplied continuously to reduce the reaction time, and slight vibration effect are applied to collect powder cling to the device.

  4. Mswi bottom ash for upgrading of biogas and landfill gas.

    Science.gov (United States)

    Mostbauer, P; Lenz, S; Lechner, P

    2008-07-01

    A new upgrading process for biogas and landfill gas (LFG) has been designed recently by the authors' institute. The process uses the alkalinity of the fine fraction of bottom ash from municipal solid waste incineration (MSWI) for sorbing CO2 and H2S. Results from process development and optimisation are presented in this paper. It is expected that nearly pure CH4 can be produced for substitution of fossil fuels. Simultaneously, the leachability of MSWI bottom ash is clearly reduced.

  5. Trace elements in coal ash

    Science.gov (United States)

    Deonarine, Amrika; Kolker, Allan; Doughten, Michael W.

    2015-01-01

    Coal ash is a residual waste product primarily produced by coal combustion for electric power generation. Coal ash includes fly ash, bottom ash, and flue-gas desulfurization products (at powerplants equipped with flue-gas desulfurization systems). Fly ash, the most common form of coal ash, is used in a range of products, especially construction materials. A new Environmental Protection Agency ruling upholds designation of coal ash as a non-hazardous waste under Subtitle D of the Resource Conservation and Recovery Act, allowing for the continued beneficial use of coal ash and also designating procedures and requirements for its storage.

  6. Electrochemical removal of cadmium from bio-ash; Elektrokemisk fjernelse af cadmium fra bioasker

    Energy Technology Data Exchange (ETDEWEB)

    Juul Pedersen, Anne; Ottosen, Lisbeth M.; Simonsen, Peter; Christensen, Terkel C.

    2004-07-01

    The potential of using the method electrodialytic remediation for removal of cadmium from bioashes has been investigated. Five different types of fly ash from biomass combustion were included in the study: 1) A straw combustion fly ash from grate-firing at Avedoere power plant. 2) A fly ash from co-firing of wood and fuel oil at Avedoere power plant. 3) A suspended, grain size fractionated straw fly ash, obtained from PSO project FU 2201, fine and coarse size fraction. The ash was originally produced at Avedoere power plant. 4) A straw pellet fly ash from dust-firing at Amager power plant. Thr five ashes were characterised, and a series of preliminary elekctrodialytic remediation experiments were conducted on each ash. In spite a significant differences between the five ashes with respect to parameters such as pH and content of cadmium, all ashes showed promising remediation potential. For all ashes cadmium concentrations below the regulatory limits for recycling were reached in one or more of the preliminary remediation experiements. The best results were obtained with the suspended straw ash from PSO FU 2201, whereas the results with the wood chips ash, due to a high initial pH value, were less sucessful, meaning that the remediation process was progressing more slowly. (BA)

  7. Reed as a gasification fuel: a comparison with woody fuels

    Directory of Open Access Journals (Sweden)

    S. Link

    2013-10-01

    Full Text Available Reed and coniferous wood can be used for energy production via thermochemical conversion, for instance by gasification. The rate-determining step of the gasification process is the reaction between the char and the gaseous environment in the gasifier, whose rate depends on variables such as pressure, temperature, particle size, mineral matter content, porosity, etc. It is known that reactivity can be improved by increasing the temperature, but on the other hand the temperature achieved in the reactor is limited due to the ash fusion characteristics. Usually, the availability of reed as a fuel is locally modest and, therefore, it must be blended with other fuels such as wood. Blending of fuels brings together several problems relating to ash behaviour, i.e. ash fusion issues. Because there is no correlation between the ash fusion characteristics of biomass blends and their individual components, it is essential to carry out prior laboratory-scale ash fusion tests on the blends. This study compares the reactivity of reed and coniferous wood, and the ash fusion characteristics of blends of reed and coniferous wood ashes. When compared with Douglas fir and reed chars, pine pellets have the highest reactivity. Reed char exhibits the lowest reactivity and, therefore, it is advantageous to gasify reed alone at higher gasification temperatures because the ash fusion temperatures of reed are higher than those of woody fuels. The ash produced by reed and wood blends can melt at lower temperatures than ash from both reed and wood gasified separately. Due to this circumstance the gasification temperature should be chosen carefully when gasification of blends is carried out.

  8. Quantification of Ash Deposit Build-up and Removal in a Straw and Wood Suspension-Fired Boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming

    2011-01-01

    The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension­fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share in...

  9. Application of advanced technologies to ash-related problems in boilers

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L. [Sandia National Labs., Livermore, CA (United States); Richards, G.; Harb, J. [Brigham Young Univ., Provo, UT (United States). Chemical Engineering Dept.

    1995-01-01

    Prediction of ash behavior in boilers has, for many years, been based on relatively simple relationships involving the composition of inorganic material in fuels. In recent years, advanced analyses for both fuels and deposits have seen increasing use in the solid fuel combustion community. The combination of the standard and advanced analyses, together with a knowledge of boiler design and operating conditions, allow better interpretation of ash behavior in boilers than has previously been possible. This paper discusses several case histories where advanced technologies have been applied to interpret ash behavior in boilers where standard techniques were insufficient. Included in the discussion are: (1) the behavior of blends of fuels; (2) explanations for markedly different behavior between fuels with similar ASTM characteristics; and (3) effects of boiler operating conditions on ash deposit formation.

  10. Melting and Sintering of Ashes

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug

    1997-01-01

    The thesis contains an experimental study of the fusion and sintering of ashes collected during straw and coal/straw co-firing.A laboratory technique for quantitative determination of ash fusion has been developed based on Simultaneous Thermal Analysis (STA). By means of this method the fraction...... of melt in the investigated ashes has been determined as a function of temperature. Ash fusion results have been correlated to the chemical and mineralogical composition of the ashes, to results from a standard ash fusion test and to results from sintering experiments. Furthermore, the ash fusion results......-firing, the model only had a qualitative agreement with the measured ash deposit formation rates.Sintering measurements were carried out by means of compression strength testing of ash pellets. This method showed to not be applicable for the salt rich fly ash derived from straw combustion. For the fly ashes...

  11. Gas generation in incinerator ash; Gasbildning i aska

    Energy Technology Data Exchange (ETDEWEB)

    Arm, Maria; Lindeberg, Johanna; Rodin, Aasa; Oehrstroem, Anna; Backman, Rainer; Oehman, Marcus; Bostroem, Dan

    2006-02-15

    In recent years, explosions have occurred in certain phases of ash handling in Sweden. Investigations have revealed that hydrogen may have been present in all cases. The hydrogen is believed to be generated by chemical reactions of aluminium and other metals within the ash in the presence of water. The purpose with this study is to increase the knowledge of gas generation of incinerator ash. Thereby, guides for appropriate ash management can be introduced and the risk for further explosions prevented. The study has comprised analyses of the ash properties, such as chemical and physical composition and the pH, of ash from 14 incineration plants (mostly waste incineration plants). Different fractions of ash materials representing different parts of the process in each plant have been analysed. Furthermore, the fuel and the technical differences between the plants have been analysed. A tool for measuring the gas generation in the laboratory has been developed and the gas generation of the different ash materials at natural and increased pH was measured. Gas analyses and thermodynamic calculations have also been performed. The results showed that: bottom ash from fluidised bed boilers generated small amounts of gas at increased pH, much smaller amounts than the idle pass, cyclone and filter ash did, bottom ash from grate fired boilers generated more gas at increased pH than their cyclone ash and filter ash, with exception of the Linkoeping plant, all bio waste incineration plants generated ash with low gas generation potential, all fly ash materials with a gas generation potential of more than 10 l/kg originated from municipal waste incineration plants, filter ash that had been stored in oxygen rich environment generated significant less gas than fresh filter ash of the same origin, hardly any other gases were generated apart from hydrogen (very small amounts of acetone, furane, benzene and most likely methane were detected in some of the ash materials), there were no

  12. Study on the NOx release rule along the boiler during pulverized coal combustion

    Institute of Scientific and Technical Information of China (English)

    JIN Jing; ZHANG Zhongxiao; LI Ruiyang

    2007-01-01

    Numerical simulation and experimental study on NOx release along the boiler during pulverized coal combustion have been conducted.With the increase of temperature the NOx emission increased and the peak value of NOx release moved forward.But when the temperature increased to a certain degree,NOx emission began to reduce.NOx emission increased with the increase of nitrogen content of coal.The peak value of NOx release moved backwards with the increase of coal rank.NOx emission increased obviously with the increase of stoichiometric ratio.There existed a critical average diameter of the pulverized coal (de).If d≤dc,NOx emission reduced with the decrease of pulverized coal size.If d>de,NOx emission reduced with the increase of the pulverized coal size.The results showed that the simulation results are in agreement with the experimental results for concentration distribution of NOx along the axis of the furnace.

  13. Measurement of temperature conditions in grate zone of a 1 MW wood-pellets boiler fired with high ash content wood-pellets

    OpenAIRE

    Skotland, Christer Heen

    2009-01-01

    The combustion of biomass could in some cases lead to ash problems induced by high temperatures such as ash sintering, agglomeration and melting. The degrees of these problems depend on the fuel feedstock and are highly dependent on the amount of potassium, sodium and chlorine in the biomass. Straw, grass, bark, branches and wood residues are typical examples of biomass fuels that are connected to the mentioned ash problems.Addition of additives in the problematic fuels is a possible measure ...

  14. Comparison of efficacy of pulverization and sterile paper point techniques for sampling root canals.

    Science.gov (United States)

    Tran, Kenny T; Torabinejad, Mahmoud; Shabahang, Shahrokh; Retamozo, Bonnie; Aprecio, Raydolfo M; Chen, Jung-Wei

    2013-08-01

    The purpose of this study was to compare the efficacy of the pulverization and sterile paper point techniques for sampling root canals using 5.25% NaOCl/17% EDTA and 1.3% NaOCl/MTAD (Dentsply, Tulsa, OK) as irrigation regimens. Single-canal extracted human teeth were decoronated and infected with Enterococcus faecalis. Roots were randomly assigned to 2 irrigation regimens: group A with 5.25% NaOCl/17% EDTA (n = 30) and group B with 1.3% NaOCl/MTAD (n = 30). After chemomechanical debridement, bacterial samplings were taken using sterile paper points and pulverized powder of the apical 5 mm root ends. The sterile paper point technique did not show growth in any samples. The pulverization technique showed growth in 24 of the 60 samples. The Fisher exact test showed significant differences between sampling techniques (P technique showed no difference between irrigation regimens. However, 17 of the 30 roots in group A and 7 of the 30 roots in group B resulted in growth as detected by pulverization technique. Data showed a significant difference between irrigation regimens (P = .03) in pulverization technique. The pulverization technique was more efficacious in detecting viable bacteria. Furthermore, this technique showed that 1.3% NaOCl/MTAD regimen was more effective in disinfecting root canals. Published by Elsevier Inc.

  15. Liquefaction behavior of finely pulverized coal. Chobifunsaitan no ekika hanno kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Y.; Kamo, T.; Miki, K.; Yamamoto, Y. (National Institute for Resources and Environment, Tsukuba (Japan))

    1992-11-05

    The reaction process of coal liquefaction which uses ultrafine pulverized coal having a particle diameter of several micrometers was investigated in order to improve the catalytic efficiency between coal and catalyst. Two kinds of samples were prepared by crushing Taiheiyo-coal into less than 100-mesh by usual technique and further pulverizing the crushed coal to several [mu]m. When iron oxide catalyst, sulfur and tetralin solvent were used, pulverizing does not bring a significant improvement in conversion rate and the yield of liquefaction oil capable of being distillated. This is considered to be due to the coagulation between fine particles before or during reaction, suggesting the importance of selecting reaction conditions etc. In the case of pulverized coal, hydrogen consumption is high and hydrogenation of heavy fractions such as SRC proceeds. When liquefaction-oil circulating solvent and red mud-sulfur-based catalyst were used, gas yield was low in pulverized coal, but no significant improvement was not shown in oil yield of liquefaction oil. The conversion rate and SRC yield were somewhat high in the case of pulverized coal. 3 figs., 2 tabs.

  16. Numerical analysis of loads effect on combustion performance and NO{sub x} emissions of a 220 MW pulverized coal boiler

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jun; Yang, Weihong; Blasiak, Wlodzimierz [Royal Institute of Technology (KTH), Stockholm (Sweden). Div. of Energy and Furnace Technology; Jankowski, Radoslaw; Kotecki, Michal; Szewczyk, Dariusz [Industrial Combustion Systems (ICS) Company, Poznan (Poland); Brzdekiewicz, Artur [Remak-Rozruch SA, Opole (Poland)

    2013-07-01

    This paper presents numerical study on the combustion performance and NO{sub x} emissions of a 220 MW pulverized coal boiler. Three different loads have been simulated with combusting coal, 200, 170 and 140 MW, respectively. In order to get as precise as possible numerical analysis results, two-step simulation method has been adopted in this work, namely, air supply system simulation and furnace simulation. After air supply system simulation, the results have been taken as the initial and boundary conditions for furnace simulation. The comparison between the measured values and predicted results from 200 MW case shows much better agreement. According to the simulation results, the adopted two-step simulation method is reasonable and suitable for predicting the characters of the flow and combustion process. It is concluded that the distributions of temperature, O{sub 2} and CO concentration inside furnace with different loads shows good similarly. The total NOx emissions decreased with the boiler load reducing, and fuel NO{sub x} has the same trend as total NO{sub x}, and fuel NO{sub x} account for about 66% in total NO{sub x} in all the three cases. More important, thermal NO{sub x} slowly decreased with the rise of boiler load. More detailed results presented in this paper enhance the understanding of combustion processes and complex flow patterns of front-wall pulverized coal boilers.

  17. Influence of staged-air on airflow, combustion characteristics and NO(x) emissions of a down-fired pulverized-coal 300 MW(e) utility boiler with direct flow split burners.

    Science.gov (United States)

    Li, Zhengqi; Kuang, Min; Zhang, Jia; Han, Yunfeng; Zhu, Qunyi; Yang, Lianjie; Kong, Weiguang

    2010-02-01

    Cold airflow experiments were conducted to investigate the aerodynamic field in a small-scale furnace of a down-fired pulverized-coal 300 MW(e) utility boiler arranged with direct flow split burners enriched by cyclones. By increasing the staged-air ratio, a deflected flow field appeared in the lower furnace; larger staged-air ratios produced larger deflections. Industrial-sized experiments on a full-scale boiler were also performed at different staged-air damper openings with measurements taken of gas temperatures in the burner region and near the right-side wall, wall heat fluxes, and gas components (O(2), CO, and NO(x)) in the near-wall region. Combustion was unstable at staged-air damper openings below 30%. For openings of 30% and 40%, late ignition of the pulverized coal developed and large differences arose in gas temperatures and heat fluxes between the regions near the front and rear walls. In conjunction, carbon content in the fly ash was high and boiler efficiency was low with high NO(x) emission above 1200 mg/m(3) (at 6% O(2) dry). For fully open dampers, differences in gas temperatures and heat fluxes, carbon in fly ash and NO(x) emission decreased yielding an increase in boiler efficiency. The optimal setting is fully open staged-air dampers.

  18. Solid fuels as engine fuels. Kiinteiden polttoaineiden kaeyttoemahdollisuudet moottoripolttoaineena

    Energy Technology Data Exchange (ETDEWEB)

    Vakkilainen, A.; Nylund, N.-O.

    1986-07-01

    The use of solid fuels as engine fuels is discussed in this literature study. The present liquid fuel engines require extensive and expensive changes to overcome difficulties due to solid fuels. The solid particles result in increasing wear in the engine, in the fuel feed system and everywhere, where the particles come into touch with moving surfaces. The rate of wear has been as high as 100-fold compared to that caused by liquid fuels. Large medium-fast or slow diesel engines seem to meet best the requirements set by solid fuels. The experiment carried out by the Swiss Sulzer Engine Works are the most promising engine experiments carried out so far. In Sulzer's experiments, coal-water slurries containing 50-70 wt-% coal have been used as the fuel. Burning has been rather complete, but wear and the high price of the coal-water slurry seem to be unsolvable problems. The development work on enines is still at an early stage and a solid fuel engine will not be manufactured in series in the near future. The pulverous fuel of the future will be a mixture of some liquid and of some solid fuel powder, and hence the handling-technical problems will be considerably smaller than using powder only. Powder manufacture with the present techniques is energy-wasting. Most engine experiments have been carried out on on coal slurries with < 30 ..mu..m particle size. It is not economic to produce such powders at present.

  19. Analysis of Chemical Reaction Kinetics Behavior of Nitrogen Oxide During Air-staged Combustion in Pulverized Boiler

    Directory of Open Access Journals (Sweden)

    Jun-Xia Zhang

    2016-03-01

    Full Text Available Because the air-staged combustion technology is one of the key technologies with low investment running costs and high emission reduction efficiency for the pulverized boiler, it is important to reveal the chemical reaction kinetics mechanism for developing various technologies of nitrogen oxide reduction emissions. At the present work, a three-dimensional mesh model of the large-scale four corner tangentially fired boiler furnace is established with the GAMBIT pre-processing of the FLUENT software. The partial turbulent premixed and diffusion flame was simulated for the air-staged combustion processing. Parameters distributions for the air-staged and no the air-staged were obtained, including in-furnace flow field, temperature field and nitrogen oxide concentration field. The results show that the air-staged has more regular velocity field, higher velocity of flue gas, higher turbulence intensity and more uniform temperature of flue gas. In addition, a lower negative pressure zone and lower O2 concentration zone is formed in the main combustion zone, which is conducive to the NO of fuel type reduced to N2, enhanced the effect of NOx reduction. Copyright © 2016 BCREC GROUP. All rights reserved Received: 5th November 2015; Revised: 14th January 2016; Accepted: 16th January 2016  How to Cite: Zhang, J.X., Zhang, J.F. (2016. Analysis of Chemical Reaction Kinetics Behavior of Nitrogen Oxide During Air-staged Combustion in Pulverized Boiler. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 100-108. (doi:10.9767/bcrec.11.1.431.100-108 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.431.100-108

  20. Physicochemical characterization of pulverized phyllite rocks to geopolymer resin synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Melo, L.G.A. [Instituto Militar de Enegenharia (IME), Rio de Janeiro, RJ (Brazil); Pires, E.F.C. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Pereira, R.A.; Silva, F.J. [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio de Raneiro (IFRJ), RJ (Brazil)

    2016-07-01

    Full text: Geopolymeric materials have common properties considered unique, such as: early-high compressive strength, durability, high chemical resistance to acids and sulfates attacks, ability to immobilize toxic and radioactive compounds, low porosity, low permeability, and resistance to high temperatures. Together with its environmental benefits, such as low energy consumption and low carbon dioxide emissions during production, these inorganic polymers are strategic materials for sustainable development and a good alternative to Portland cement. The main objective for introducing alternative materials is to lower the associated costs of its industrial process. Thus, the use of phyllite as the geopolymer precursor, is encouraged by its abundance, low cost, and the fact that it already is applied to the ceramic industries as kaolin substitute. This paper presents a physical characterization using TEM, SEM, XRD and XRF techniques of two pulverized phyllite rocks used as geopolymer precursors for refractory applications. It was found that both phyllite rocks studied have a high quartz content of approximately 50% that can be explored as 'filler' function in the microstructure, which stabilizes residual tensions after curing. Kaolinite and muscovite minerals are present up to 40% and are responsible for the high strengths in the geopolymer resins, as determined by compressive strength tests. (author)

  1. Agglomeration in Stripper Ash Coolers and Its Possible Remedial Solutions: a Case Study

    Science.gov (United States)

    Singh, Ravi Inder

    2016-04-01

    The bottom ash of circulating fluidized bed (CFB) boiler contains large amounts of physical heat. When low quality coals are used in these types of boilers, the ash content is normally more than 40 % and the physical heat loss is approximately 3 % if the bottom ash is discharged without cooling. Bottom ash cooler (BAC) is often used to treat the high temperature bottom ash to reclaim heat, and to facilitate the easily handling and transportation of ash. The CFB boiler at BLA Power, Newari, MP (India) is facing problems of clinker formation in strip ash coolers of plant since the installation of unit. These clinkers are basically agglomerates, which leads to defluidization of stripper ash cooler (BAC) units. There are two strip ash coolers in unit. Each strip ash cooler is capable of working independently. The proper functioning of both strip coolers is very important as it is going to increase the combustion efficiency of boiler by stripping of fine unburnt coal particles from ash, which are injected into the furnace. In this paper causes, characterization of agglomerates, thermo gravimetric analysis of fuel used, particular size distribution of coal and sand and possible remedial solution to overcome these agglomerates in strip ash coolers has also been presented. High temperature in compact separators, non uniform supply of coal and not removing small agglomerates from stripper ash cooler are among main causes of agglomeration in stripper ash cooler. Control of compact separator temperature, replacing 10-12 % of bed material and cleaning stripper ash cooler periodically will decrease agglomeration in stripper ash cooler of unit.

  2. Rheology of fly ashes from coal and biomass co-combustion

    DEFF Research Database (Denmark)

    Arvelakis, Stelios; Frandsen, Flemming

    2010-01-01

    The presence of large amounts of alkali metals, chlorine and sulphur in most biomass fuels - compared to coal - can create serious ash-related problems such as deposition, agglomeration and/or corrosion. This paper discusses the viscosity characteristics of fly ash from the co-combustion of various...

  3. Ash cloud aviation advisories

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T.J.; Ellis, J.S. [Lawrence Livermore National Lab., CA (United States); Schalk, W.W.; Nasstrom, J.S. [EG and G, Inc., Pleasanton, CA (United States)

    1992-06-25

    During the recent (12--22 June 1991) Mount Pinatubo volcano eruptions, the US Air Force Global Weather Central (AFGWC) requested assistance of the US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) in creating volcanic ash cloud aviation advisories for the region of the Philippine Islands. Through application of its three-dimensional material transport and diffusion models using AFGWC meteorological analysis and forecast wind fields ARAC developed extensive analysis and 12-hourly forecast ash cloud position advisories extending to 48 hours for a period of five days. The advisories consisted of ``relative`` ash cloud concentrations in ten layers (surface-5,000 feet, 5,000--10,000 feet and every 10,000 feet to 90,000 feet). The ash was represented as a log-normal size distribution of 10--200 {mu}m diameter solid particles. Size-dependent ``ashfall`` was simulated over time as the eruption clouds dispersed. Except for an internal experimental attempt to model one of the Mount Redoubt, Alaska, eruptions (12/89), ARAC had no prior experience in modeling volcanic eruption ash hazards. For the cataclysmic eruption of 15--16 June, the complex three-dimensional atmospheric structure of the region produced dramatically divergent ash cloud patterns. The large eruptions (> 7--10 km) produced ash plume clouds with strong westward transport over the South China Sea, Southeast Asia, India and beyond. The low-level eruptions (< 7 km) and quasi-steady-state venting produced a plume which generally dispersed to the north and east throughout the support period. Modeling the sequence of eruptions presented a unique challenge. Although the initial approach proved viable, further refinement is necessary and possible. A distinct need exists to quantify eruptions consistently such that ``relative`` ash concentrations relate to specific aviation hazard categories.

  4. Reuse of Partially Sulphated CFBC Ash as an SO2 Sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yinghai; Jia, Lufei; Anthony, E.J. [CanmetENERGY, 1 Haanel Drive, Ottawa, Ontario, K1A1M1 (Canada); Nobili, M.; Telesca, A. [Department of Environmental Engineering and Physics, University of Basilicata, Viale dell' Ateneo, Lucano 10, 85100 Potenza (Italy); Montagnaro, F. [Department of Chemistry, University of Naples ' Federico II' , Monte Sant' Angelo, 80126 Naples (Italy)

    2010-06-15

    Ashes produced from fluidized bed combustors (FBC) burning high-sulphur fuels often contain 20-30 % unreacted CaO because of the limestone added to remove SO2 in situ. This paper presents the results from experiments into reactivating partially sulphated FBC ash (both bed ash and fly ash) with liquid water, steam and sodium carbonate. The water- or steam-hydrated ashes were subsequently re-sulphated in a thermogravimetric analyzer (TGA) with simulated flue gas. The TGA results show that, while liquid water and steam successfully hydrate and reactivate the unreacted CaO in the bed ash, the treated ashes sulphated to widely different extents. Attempts to reactivate fly ash with hydration failed, although fly ash by itself is extremely reactive. A pilot-scale mini-circulating FBC (CFBC) was also used to evaluate the results of reactivation on the bed ash by hydrating with liquid water and admixtures of inorganic salt (Na2CO3) in the form of either powder or solution. When the treated ash was re-injected into the combustor with the fuel, the effect on SO2 removal efficiency was negligible if Na2CO3 was added as powder. Doping with aqueous solution resulted in enhanced SO2 removal; however, the extent was lower than the level achieved if only water hydration was employed. Increasing the amount of water (from 10% to 30%) to reactivate the ash did not improve the sulphur capture capacity in the mini-CFBC. Overall, this study suggests that the most practical way for re-use of the partially sulphated bed ash as a sulphur sorbent is reactivation by water. A proposal for utilization of the fly ash in an economically reasonable way is also discussed.

  5. COMPUTATIONAL MODELING AND EXPERIMENTAL STUDIES ON NOx REDUCTION UNDER PULVERIZED COAL COMBUSTION CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Subha K. Kumpaty; Kannikeswaran Subramanian; Victor P. Nokku; Tyrus L. Hodges; Adel Hassouneh; Ansumana Darboe; Sravan K. Kumpati

    1998-06-01

    In this work, both computer simulation and experimental studies were conducted to investigate several strategies for NO{sub x} reduction under pulverized coal combustion conditions with an aim to meet the stringent environmental standards for NO{sub x} control. Both computer predictions and reburning experiments yielded favorable results in terms of NO{sub x} control by reburning with a combination of methane and acetylene as well as non-selective catalytic reduction of NO{sub x} with ammonia following reburning with methane. The greatest reduction was achieved at the reburning stoichiometric ratio of 0.9; the reduction was very significant, as clearly shown in Chapters III and V. Both the experimental and computational results favored mixing gases: methane and acetylene (90% and 10% respectively) and methane and ammonia (98% and 2%) in order to get optimum reduction levels which can not be achieved by individual gases at any amounts. Also, the above gaseous compositions as reburning fuels seemed to have a larger window of stoichiometric ratio (SR2 < 0.9) as opposed to just methane (SR2=0.9) so as to reduce and keep NO{sub x} at low ppm levels. From the various computational runs, it has been observed that although there are several pathways that contribute to NO{sub x} reduction, the key pathway is NO {r_arrow} HCN {r_arrow} NH{sub 3} {r_arrow} N{sub 2} + H{sub 2}. With the trends established in this work, it is possible to scale the experimental results to real time industrial applications using computational calculations.

  6. Comparison of Ash from PF and CFB Boilers and Behaviour of Ash in Ash Fields

    Science.gov (United States)

    Arro, H.; Pihu, T.; Prikk, A.; Rootamm, R.; Konist, A.

    Over 90% of electricity produced in Estonia is made by power plants firing local oil shale and 25% of the boilers are of the circulating fluidised bed (CFB) variety. In 2007 approximately 6.5 million tons of ash was acquired as a byproduct of using oil shale for energy production. Approximately 1.5 million tons of that was ash from CFB boilers. Such ash is deposited in ash fields by means ofhydro ash removal.

  7. STRATEGIES AND TECHNOLOGY FOR MANAGING HIGH-CARBON ASH

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Eric Suuberg; John Veranth; Xu Chen; Indrek Kulaots

    2004-02-13

    The overall objective of the present project was to identify and assess strategies and solutions for the management of industry problems related to carbon in ash. Specific issues addressed included: (1) the effect of parent fuel selection on ash properties and adsorptivity, including a first ever examination of the air entrainment behavior of ashes from alternative (non-coal) fuels; (2) the effect of various low-NOx firing modes on ash properties and adsorptivity based on pilot-plant studies; and (3) the kinetics and mechanism of ash ozonation. This laboratory data has provided scientific and engineering support and underpinning for parallel process development activities. The development work on the ash ozonation process has now transitioned into a scale-up and commercialization project involving a multi-industry team and scheduled to begin in 2004. This report describes and documents the laboratory and pilot-scale work in the above three areas done at Brown University and the University of Utah during this three-year project.

  8. Fusion characterization of biomass ash

    DEFF Research Database (Denmark)

    Ma, Teng; Fan, Chuigang; Hao, Lifang

    2016-01-01

    The ash fusion characteristics are important parameters for thermochemical utilization of biomass. In this research, a method for measuring the fusion characteristics of biomass ash by Thermo-mechanical Analyzer, TMA, is described. The typical TMA shrinking ratio curve can be divided into two...... stages, which are closely related to ash melting behaviors. Several characteristics temperatures based on the TMA curves are used to assess the ash fusion characteristics. A new characteristics temperature, Tm, is proposed to represent the severe melting temperature of biomass ash. The fusion...... characteristics of six types of biomass ash have been measured by TMA. Compared with standard ash fusibility temperatures (AFT) test, TMA is more suitable for measuring the fusion characteristics of biomass ash. The glassy molten areas of the ash samples are sticky and mainly consist of K-Ca-silicates....

  9. Ash formation, transformations and deposition during fluidized bed combustion and gasification

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, E.; Lind, T.; Kurkela, J.; Latva-Somppi, J.; Lyyraenen, J.; Valmari, T. [VTT Chemical Technology, Espoo (Finland). Aerosol Technology Group

    1998-12-31

    In this work, ash formation and transformations as well as bed agglomeration and fly ash deposition onto the heat exchanger tubes during fluidised bed combustion and gasification were studied using experimental methods and chemical equilibrium calculations. The fuels were coal and pulp and paper mill sludges as well as different wood-based waste materials. The volatilized heavy metal behaviour during pressurized combustion and gasification was studied using chemical equilibrium calculations. The classification of trace elements into four groups presented in this report matched well with the former studies. The release of ash-forming compounds during pyrolysis was studied experimentally in a heated grid reactor. Very small fractions of Si, Al, Fe, Ca, Mg, Na, and K were released from the biomass fuels, peat, and coals during pyrolysis at 900 deg C. Bottom ash during combustion of biomass fuels was found to be formed from bed material and ash-forming compounds. Ash-forming compounds were found to adhere to the bed material by two mechanisms: (i) by deposition of the non-volatile ash compounds as particles onto the bed particle surface, and (ii) by chemical reactions of the volatile ash compounds, e.g., K and Pb, with the bed particles. The size distributions of the fly ash particles were bimodal. The fine mode particles (Dp < 1 {mu}m) were formed by nucleation of the volatilised refractory oxides, e.g., SiO{sub 2}. The nucleated particles grew further by coagulation and condensation of the volatile ash compounds. The coarse fly ash fraction (Dp > 1 {mu}m) was formed from the non-volatile ash compounds, e.g., Ca and Si. The coarse mode particles were agglomerated and irregular in shape. During sludge combustion, the fly ash was mostly in the supermicron size range. This is beneficial for conventional flue gas cleaning devices that are most effective in this particle size. This is especially true for paper mill sludges, producing negligible concentrations of submicron

  10. Effect of mixes made of coal bottom ash and fly ash on the mechanical strength and porosity of Portland cement

    Directory of Open Access Journals (Sweden)

    Argiz, C.

    2013-03-01

    Full Text Available New additions to the cement are needed to achieve a more sustainable and durable construction material. Within this context, bottom ashes can be used as a main constituent of Portland cements when it is mixed in an optimized proportion with fly ashes. The mechanical characteristics of standarized mortars made of mixes of pulverized coal combustion bottom and fly ashes are studied. The mortars were made of ordinary Portland cement (CEM I 42.5 N and mixes of bottom ashes with fly ashes in similar proportions to those of CEM II/A-V, CEM II/B-V and CEM IV/A (V. Summing up, it can be said that the utilization of bottom ashes mixed with fly ashes in replacement levels from 0% to 100% do not affect significantively on the mechanical caracteristics of the mortars considered in the present study which had an addition maximum content of 35%.

    La utilización de nuevas adiciones en el cemento es necesaria con el fin de obtener un material más sostenible y durable. En este sentido, las cenizas de fondo o cenicero de las centrales termoeléctricas de carbón se podrían reciclar siendo empleadas como un componente principal de los cementos Portland. Se han estudiado las propiedades mecánicas de unos morteros normalizados elaborados con mezclas de cenizas volantes con cenizas de fondo fabricados con unos porcentajes similares a los correspondientes de los CEM II/A-V, CEM II/B-V y CEM IV/A (V. En conclusión, la utilización de mezclas de cenizas de fondo o cenicero con cenizas volantes sustituyendo a éstas últimas entre el 0% y el 100%, no influye significativamente en el comportamiento mecánico de los morteros estudiados en los que el contenido máximo de adición ha sido del 35%, si bien afecta a determinados aspectos microestructurales, como la cantidad y distribución de poros capilares.

  11. Ash properties of some dominant Greek forest species

    Energy Technology Data Exchange (ETDEWEB)

    Liodakis, S. [Laboratory of Inorganic and Analytical Chemistry, Department of Chemical Engineering, National Technical University of Athens (NTUA), 9 Iroon Polytechniou Street, Athens 157 73 (Greece)]. E-mail: liodakis@central.ntua.gr; Katsigiannis, G. [Laboratory of Inorganic and Analytical Chemistry, Department of Chemical Engineering, National Technical University of Athens (NTUA), 9 Iroon Polytechniou Street, Athens 157 73 (Greece); Kakali, G. [Laboratory of Inorganic and Analytical Chemistry, Department of Chemical Engineering, National Technical University of Athens (NTUA), 9 Iroon Polytechniou Street, Athens 157 73 (Greece)

    2005-10-15

    The elemental and chemical wood ash compositions of six dominant Greek fuels was investigated using a variety of techniques, including thermal gravimetric analysis (TG), differential thermal analysis (DTA), atomic absorption spectroscopy (AAS) and X-ray diffraction (XRD). In addition, the alkalinity of wood ash was determined by titration. The ash was prepared by combustion at low (600 deg. C), middle (800 deg. C) and high temperatures (1000 deg. C). The ash composition is very important because thousands of hectares of wildlands are burned annually in Greece. The resulting deposits affect soil properties (i.e., pH) and provide a source of inorganic constituents (i.e., Ca, K, Na, Mg, etc.), while the most soluble compounds (i.e., sodium and potassium hydroxides and carbonates) do not persist through the wet season. The samples selected were: Pinus halepensis (Aleppo pine), Pinus brutia (Calabrian pine), Olea europaea (Olive), Cupressus sempervirens (Italian cypress), Pistacia lentiscus (Mastic tree), Quercus coccifera (Holly oak)

  12. Behaviour of peat ash in high-temperature processes

    Energy Technology Data Exchange (ETDEWEB)

    Moilanen, A.

    1986-01-01

    The ash-forming constituents are in peat as minerals and bound in the organic framework. The kind of binding is dependent on peat type, plant species composition, acidity of the peatland, etc. Studies carried out with brown coal have indicated that the forms of ash occurrence in the fuel have an influence on the slagging ehaviour of ash in the process. The behaviour is also dependent on the reactor type and conditions in the reactor, for example, on the composition of gas atmosphere, on temperature, and gas flows. For example, the reducing conditions affect especially the occurrence of iron in different oxidation degrees in gasification, and this affects further the melting behaviour of ash. In brown coal gasification, as much as a third of the iron content was found to be reduced to metallic iron in the fluid-bed gasifier. To forecast the slagging behaviour of ash, the melting temperatures of ash are measured. Fouling or partial melting of ash cannot always be monitored with standard measuring methods, as these phenomena may start already at temperatures 200 deg C lower than the lowest melting temperature. THey can be studied for example with thermochemical methods.

  13. Scrap tire ashes in portland cement production

    Directory of Open Access Journals (Sweden)

    Mónica Adriana Trezza

    2009-01-01

    Full Text Available Scrap tires are not considered harmful waste, but their stocking and disposal are a potential health and environmental risk. Properly controlled calcinations at high temperatures make tire combustion an interesting alternative due to its high calorific power, comparable to that of fuel-oil. Consequently, using them as an alternative combustible material in cement kilns makes it possible to give it a valuable use. However, it remains to be assured whether the impurities added to the clinker through these fuels do not affect its structure or properties.This paper shows the studies carried out on different clinkers under laboratory conditions with different levels of addition of scrap tire ashes, added by partially replacing traditional fuel in cement kilns.

  14. Re-burning of ash in grate boilers; Omfoerbraenning av askor i rosterpannor

    Energy Technology Data Exchange (ETDEWEB)

    Bergqvist, Kristina; Myringer, Aase; Nordgren, Daniel; Rydberg, Stina [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

    2005-03-01

    High contents of unburnt carbon in ashes that are dumped or recycled, is questionable from both an economical and an environmental point of view. The content of unburnt carbon in bottom and fly ash from grate boilers varies greatly between different plants but can sometimes exceed 50 %. Re-burning of ash that is separated before a final dust separation, is a relatively cheep and simple method for reducing the content of unburnt carbon in ash, which both reduces the fuel cost and the deposit cost, i.e. the cost of landfilling or recycling. As from 2005 it is prohibited to deposit ash with a too high content of unburnt organic material; the content is limited to 18 weight % of unburnt carbon. The study was carried out in two phases. The aim of the first phase was to map the different techniques used for re-burning ash that are used in grate boilers today. The mapping was done through telephone interviews and comprises technical descriptions of the systems, gathering of operational know-how, installations costs and the effect of the systems on the amount of ash generated at the plants and the content of unburnt carbon in the ash. In order to accomplish a deeper technical and economical evaluation of ash re-burning systems, the second phase involved field studies at two plants. In addition screening tests were done to investigate the connection between the content of unburnt carbon and particle size. The potential of reducing the amount of circulated inorganic material by sieving the ash before bringing it back to the furnace could thereby be determined. 13 plants that utilize re-burning of ash were identified, of which two plants re-burn the bottom ash that floats up to the surface in the wet ash removal system. The remaining 11 plants re-burn fly ash. At three plants the fly ash is first separated in a mesh sieve or similar equipment and only the coarser fly ash is re-burnt. As the amount of bottom ash that surfaces in the wet ash-removal is relatively small

  15. Behavior of Alkali Metals and Ash in a Low-Temperature Circulating Fluidized Bed (LTCFB) Gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk

    2016-01-01

    W and a 6 MW LTCFBgasifier. Of the total fuel ash entering the system, the largest fraction (40−50%) was retained in the secondary cyclone bottoms,while a lower amount (8−10%) was released as dust in the exit gas. Most of the alkali and alkaline earth metals were retained inthe solid ash, along with Si...... by the particle size and the cut size ofthe primary and secondary cyclones. A model accounting for the ash collection by the plant cyclones was shown to predict theproduct gas ash particle release reasonably well....

  16. Ash transformation in suspension fired boilers co-firing coal and straw

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn;

    The properties of the ash from co-firing of coal and straw have a large influence on boiler operation, flue gas cleaning equipment and appropriate utilization of the fly ash. A study on the fuel composition and local conditions influence on fly ash properties has been done by making entrained flow...... reactor experiments with co-firing of coal and straw, making mineral and alkali vapor laboratory reactor experiments and by developing a model of KCl reaction with kaolin. The results include correlations that can be used to estimate the speciation of potassium in the fly ash when co-firing straw...

  17. Technology for processing ash from thermal/electric plants without waste products

    Energy Technology Data Exchange (ETDEWEB)

    Tyurnikova, V.I.; Krasnikova, N.A.; Panin, A.S.; Konovalenko, P.F.

    1979-07-01

    Possibility of using flotation for enriching volatile ash from heating/electric power stations are investigated. On ash samples containing 9 percent carbon from the Nikolaev thermal/ electric plant, it was demonstrated that by using flotation with an apolar collector and T-66 reagent, the ash content was increased to 98.6% permitting it to be used for producing high ash construction materials. A foam carbon-containing product from the process has a heat of combustion of 4,000 kilocalories/ kilogram and can be reused as a fuel. Flowsheet for the flotation process is presented.

  18. TASK 3.4--IMPACTS OF COFIRING BIOMASS WITH FOSSIL FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Christopher J. Zygarlicke; Donald P. McCollor; Kurt E. Eylands; Melanie D. Hetland; Mark A. Musich; Charlene R. Crocker; Jonas Dahl; Stacie Laducer

    2001-08-01

    With a major worldwide effort now ongoing to reduce greenhouse gas emissions, cofiring of renewable biomass fuels at conventional coal-fired utilities is seen as one of the lower-cost options to achieve such reductions. The Energy & Environmental Research Center has undertaken a fundamental study to address the viability of cofiring biomass with coal in a pulverized coal (pc)-fired boiler for power production. Wheat straw, alfalfa stems, and hybrid poplar were selected as candidate biomass materials for blending at a 20 wt% level with an Illinois bituminous coal and an Absaloka subbituminous coal. The biomass materials were found to be easily processed by shredding and pulverizing to a size suitable for cofiring with pc in a bench-scale downfired furnace. A literature investigation was undertaken on mineral uptake and storage by plants considered for biomass cofiring in order to understand the modes of occurrence of inorganic elements in plant matter. Sixteen essential elements, C, H, O, N, P, K, Ca, Mg, S, Zn, Cu, Fe, Mn, B, Mo, and Cl, are found throughout plants. The predominant inorganic elements are K and Ca, which are essential to the function of all plant cells and will, therefore, be evenly distributed throughout the nonreproductive, aerial portions of herbaceous biomass. Some inorganic constituents, e.g., N, P, Ca, and Cl, are organically associated and incorporated into the structure of the plant. Cell vacuoles are the repository for excess ions in the plant. Minerals deposited in these ubiquitous organelles are expected to be most easily leached from dry material. Other elements may not have specific functions within the plant, but are nevertheless absorbed and fill a need, such as silica. Other elements, such as Na, are nonessential, but are deposited throughout the plant. Their concentration will depend entirely on extrinsic factors regulating their availability in the soil solution, i.e., moisture and soil content. Similarly, Cl content is determined

  19. TASK 3.4--IMPACTS OF COFIRING BIOMASS WITH FOSSIL FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Christopher J. Zygarlicke; Donald P. McCollor; Kurt E. Eylands; Melanie D. Hetland; Mark A. Musich; Charlene R. Crocker; Jonas Dahl; Stacie Laducer

    2001-08-01

    With a major worldwide effort now ongoing to reduce greenhouse gas emissions, cofiring of renewable biomass fuels at conventional coal-fired utilities is seen as one of the lower-cost options to achieve such reductions. The Energy & Environmental Research Center has undertaken a fundamental study to address the viability of cofiring biomass with coal in a pulverized coal (pc)-fired boiler for power production. Wheat straw, alfalfa stems, and hybrid poplar were selected as candidate biomass materials for blending at a 20 wt% level with an Illinois bituminous coal and an Absaloka subbituminous coal. The biomass materials were found to be easily processed by shredding and pulverizing to a size suitable for cofiring with pc in a bench-scale downfired furnace. A literature investigation was undertaken on mineral uptake and storage by plants considered for biomass cofiring in order to understand the modes of occurrence of inorganic elements in plant matter. Sixteen essential elements, C, H, O, N, P, K, Ca, Mg, S, Zn, Cu, Fe, Mn, B, Mo, and Cl, are found throughout plants. The predominant inorganic elements are K and Ca, which are essential to the function of all plant cells and will, therefore, be evenly distributed throughout the nonreproductive, aerial portions of herbaceous biomass. Some inorganic constituents, e.g., N, P, Ca, and Cl, are organically associated and incorporated into the structure of the plant. Cell vacuoles are the repository for excess ions in the plant. Minerals deposited in these ubiquitous organelles are expected to be most easily leached from dry material. Other elements may not have specific functions within the plant, but are nevertheless absorbed and fill a need, such as silica. Other elements, such as Na, are nonessential, but are deposited throughout the plant. Their concentration will depend entirely on extrinsic factors regulating their availability in the soil solution, i.e., moisture and soil content. Similarly, Cl content is determined

  20. Co-combustion of fossil fuels and waste

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao

    2011-05-15

    The Ph.D. thesis deals with the alternative and high efficiency methods of using waste-derived fuels in heat and power production. The focus is on the following subjects: 1) co-combustion of coal and solid recovered fuel (SRF) under pulverized fuel combustion conditions; 2) dust-firing of straw and the utilization of a waste-derived material as an additive; 3) the combustion of a biomass residue rich in phosphorus. Co-combustion of coal and SRF was conducted in an entrained flow reactor (EFR). The work revealed that when coal was co-fired with up to 25 wt% SRF, the burnout and the emissions of SO{sub 2} and NO were decreased with increasing share of SRF. The Cl content in the fly ash was very low (<0.07 wt%) when coal was co-fired up to 25 wt% SRF, indicating that the majority of the Cl in the SRF were released to gas phase during cocombustion. The formation of fouling deposits on a probe was reduced with increasing share of SRF and the resulting deposits had a very small Cl content (<0.01 wt%). On the other hand, when NaCl or PVC was added to the mixture of coal and SRF, the formation of alkali chlorides was significantly promoted. The partitioning of trace elements (As, Cd, Cr, Pb, Sb and Zn) during co-combustion of coal and SRF was investigated through the experiments in the EFR. They revealed that As, Cd, Pb, Sb and Zn were highly volatile during combustion, while the volatility of Cr was relatively low. The volatility of Cd, Pb and Zn increased significantly with the injection of Cl based additives such as PVC and NaCl, while the addition of ammonium sulphate generally decreased the volatility of trace elements. The addition of kaolinite reduced the volatility of Pb, while the effect on other trace elements was insignificant. Full-scale tests on co-combustion of coal and SRF were carried out in a pulverized coal-fired power plant, and the formation of fine particles was evaluated by applying a low-pressure cascade impactor. Compared to dedicated coal

  1. Fuel nitrogen conversion in solid fuel fired systems

    Energy Technology Data Exchange (ETDEWEB)

    Glarborg, P.; Jensen, A.D.; Johnsson, J.E. [Technical University of Denmark, Lyngby (Denmark). Department of Chemical Engineering

    2003-07-01

    Understanding of the chemical and physical processes that govern formation and destruction of nitrogen oxides (NO{sub x}) in combustion of solid fuels continues to be a challenge. Even though this area has been the subject of extensive research over the last three decades, there are still unresolved issues that may limit the potential of primary measures for NO{sub x} control. In most solid fuel fired systems oxidation of fuel-bound nitrogen constitutes the dominating source of nitrogen oxides. The present paper reviews some fundamental aspects of fuel nitrogen conversion in these systems, emphasizing mostly combustion of coal since most previous work deal with this fuel. However, also results on biomass combustion is discussed. Homogeneous and heterogeneous pathways in fuel NO formation and destruction are discussed and the effect of fuel characteristics, devolatilization conditions and combustion mode on the oxidation selectivity towards NO and N{sub 2} is evaluated. Results indicate that even under idealized conditions, such as a laminar pulverized-fuel flame, the governing mechanisms for fuel nitrogen conversion are not completely understood. Light gases, tar, char and soot may all be important vehicles for fuel-N conversion, with their relative importance depending on fuel rank and reaction conditions. Oxygen availability and fuel-nitrogen level are major parameters determining the oxidation selectivity of fuel-N towards NO and N{sub 2}, but also the ability of char and soot to reduce NO is potentially important. The impact of fuel/oxidizer mixing pattern on NO formation appears to be less important in solid-fuel flames than in homogeneous flames. (author)

  2. MAT 126 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    stylia

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MAT 126 Week 1 DQ 1 (Ash) MAT 126 Week 1 Quiz (Ash) MAT 126 Week 1 Written Assignment (Arithmetic and geometric sequence) (Ash) MAT 126 Week 2 DQ 1 (Ash) MAT 126 Week 2 DQ 2 (Ash) MAT 126 Week 2 Assignment Is It Fat Free (Ash) MAT 126 Week 2 Quiz (Ash) MAT 126 Week 3 DQ 1 (Ash) MAT 126 Week 3 DQ 2 (Ash) MAT 126 Week 3 Assignment Quadratic Equations (Ash) MAT 126 Week 3 Quiz (Ash) MAT 126...

  3. Fuel related risks; Braenslerisker

    Energy Technology Data Exchange (ETDEWEB)

    Englund, Jessica; Sernhed, Kerstin; Nystroem, Olle; Graveus, Frank (Grontmij AB, (Sweden))

    2012-02-15

    The project, within which this work report was prepared, aimed to complement the Vaermeforsk publication 'Handbook of fuels' on fuel related risks and measures to reduce the risks. The fuels examined in this project where the fuels included in the first version of the handbook from 2005 plus four additional fuels that will be included in the second and next edition of the handbook. Following fuels were included: woodfuels (sawdust, wood chips, powder, briquettes), slash, recycled wood, salix, bark, hardwood, stumps, straw, reed canary grass, hemp, cereal, cereal waste, olive waste, cocoa beans, citrus waste, shea, sludge, forest industrial sludge, manure, Paper Wood Plastic, tyre, leather waste, cardboard rejects, meat and bone meal, liquid animal and vegetable wastes, tall oil pitch, peat, residues from food industry, biomal (including slaughterhouse waste) and lignin. The report includes two main chapters; a general risk chapter and a chapter of fuel specific risks. The first one deals with the general concept of risk, it highlights laws and rules relevant for risk management and it discuss general risks that are related to the different steps of fuel handling, i.e. unloading, storing, processing the fuel, transportation within the facility, combustion and handling of ashes. The information that was used to produce this chapter was gathered through a literature review, site visits, and the project group's experience from risk management. The other main chapter deals with fuel-specific risks and the measures to reduce the risks for the steps of unloading, storing, processing the fuel, internal transportation, combustion and handling of the ashes. Risks and measures were considered for all the biofuels included in the second version in the handbook of fuels. Information about the risks and risk management was gathered through interviews with people working with different kinds of fuels in electricity and heat plants in Sweden. The information from

  4. Characteristics of fly ashes from full-scale coal-fired power plants and their relationship to mercury adsorption

    Science.gov (United States)

    Lu, Y.; Rostam-Abadi, M.; Chang, R.; Richardson, C.; Paradis, J.

    2007-01-01

    Nine fly ash samples were collected from the particulate collection devices (baghouse or electrostatic precipitator) of four full-scale pulverized coal (PC) utility boilers burning eastern bituminous coals (EB-PC ashes) and three cyclone utility boilers burning either Powder River Basin (PRB) coals or PRB blends,(PRB-CYC ashes). As-received fly ash samples were mechanically sieved to obtain six size fractions. Unburned carbon (UBC) content, mercury content, and Brunauer-Emmett-Teller (BET)-N2 surface areas of as-received fly ashes and their size fractions were measured. In addition, UBC particles were examined by scanning electron microscopy, high-resolution transmission microscopy, and thermogravimetry to obtain information on their surface morphology, structure, and oxidation reactivity. It was found that the UBC particles contained amorphous carbon, ribbon-shaped graphitic carbon, and highly ordered graphite structures. The mercury contents of the UBCs (Hg/UBC, in ppm) in raw ash samples were comparable to those of the UBC-enriched samples, indicating that mercury was mainly adsorbed on the UBC in fly ash. The UBC content decreased with a decreasing particle size range for all nine ashes. There was no correlation between the mercury and UBC contents of different size fractions of as-received ashes. The mercury content of the UBCs in each size fraction, however, generally increased with a decreasing particle size for the nine ashes. The mercury contents and surface areas of the UBCs in the PRB-CYC ashes were about 8 and 3 times higher than UBCs in the EB-PC ashes, respectively. It appeared that both the particle size and surface area of UBC could contribute to mercury capture. The particle size of the UBC in PRB-CYC ash and thus the external mass transfer was found to be the major factor impacting the mercury adsorption. Both the particle size and surface reactivity of the UBC in EB-PC ash, which generally had a lower carbon oxidation reactivity than the PRB

  5. Gasification in pulverized coal flames. First annual progress report, July 1975--June 1976

    Energy Technology Data Exchange (ETDEWEB)

    Lenzer, R. C.; George, P. E.; Thomas, J. F.; Laurendeau, N. M.

    1976-07-01

    This project concerns the production of power and synthesis gas from pulverized coal via suspension gasification. Swirling flow in both concentric jet and cyclone gasifiers will separate oxidation and reduction zones. Gasifier performance will be correlated with internally measured temperature and concentration profiles. A literature review of vortex and cyclone reactors is complete. Preliminary reviews of confined jet reactors and pulverized coal reaction models have also been completed. A simple equilibrium model for power gas production is in agreement with literature correlations. Cold gas efficiency is not a suitable performance parameter for combined cycle operation. The coal handling facility, equipped with crusher, pulverizer and sieve shaker, is in working order. Test cell flow and electrical systems have been designed, and most of the equipment has been received. Construction of the cyclone gasifier has begun. A preliminary design for the gas sampling system, which will utilize a UTI Q-30C mass spectrometer, has been developed.

  6. Use of disposed waste ash from landfills to replace Portland cement.

    Science.gov (United States)

    Rukzon, Sumrerng; Chindaprasirt, Prinya

    2009-09-01

    In this study, waste ash was utilized as a pozzolanic material in blended Portland cement in order to reduce negative environmental effects and landfill volume required to dispose of waste ash. The influence of waste ash, namely palm oil fuel ash, rice husk ash and fly ash on compressive strength and sulfate resistance in mortar were studied and evaluated by some accelerated short-term techniques in sodium sulfate solutions. Ordinary Portland cement (OPC) was partially replaced with ground palm oil fuel ash (POA), ground rice husk ash (RHA) and classified fly ash (FA). Single pozzolan and a blend of equal weight portions of POA, RHA and FA were also used. The resistance to sulfate attack of mortar improves substantially with partial replacement of OPC with POA, RHA and FA. The use of a blend of equal weight portions of FA and POA or RHA produced mixes with good strength and resistance to sulfate attack. POA, RHA and FA have a high potential to be used as a pozzolanic material.

  7. Wildland fire ash: Production, composition and eco-hydro-geomorphic effects

    Science.gov (United States)

    Bodi, Merche B.; Martin, Deborah; Balfour, Victoria N.; Santin, Cristina; Doerr, Stefan H.; Pereira, Paulo; Cerda, Artemi; Mataix-Solera, Jorge

    2014-01-01

    Fire transforms fuels (i.e. biomass, necromass, soil organic matter) into materials with different chemical and physical properties. One of these materials is ash, which is the particulate residue remaining or deposited on the ground that consists of mineral materials and charred organic components. The quantity and characteristics of ash produced during a wildland fire depend mainly on (1) the total burned fuel (i.e. fuel load), (2) fuel type and (3) its combustion completeness. For a given fuel load and type, a higher combustion completeness will reduce the ash organic carbon content, increasing the relative mineral content, and hence reducing total mass of ash produced. The homogeneity and thickness of the ash layer can vary substantially in space and time and reported average thicknesses range from close to 0 to 50 mm. Ash is a highly mobile material that, after its deposition, may be incorporated into the soil profile, redistributed or removed from a burned site within days or weeks by wind and water erosion to surface depressions, footslopes, streams, lakes, reservoirs and, potentially, into marine deposits.Research on the composition, properties and effects of ash on the burned ecosystem has been conducted on material collected in the field after wildland and prescribed fires as well as on material produced in the laboratory. At low combustion completeness (typically T  450 °C), most organic carbon is volatized and the remaining mineral ash has elevated pH when in solution. It is composed mainly of calcium, magnesium, sodium, potassium, silicon and phosphorous in the form of inorganic carbonates, whereas at T > 580 °C the most common forms are oxides. Ash produced under lower combustion completeness is usually darker, coarser, and less dense and has a higher saturated hydraulic conductivity than ash with higher combustion completeness, although physical reactions with CO2 and when moistened produce further changes in ash characteristics.As a new

  8. Application and Operational Maintenance Experience of Plasma Pulverized Coal Ignition Combustion Technology%等离子煤粉点火燃烧技术的应用及运维经验

    Institute of Scientific and Technical Information of China (English)

    刘俊臻

    2012-01-01

    介绍了交流等离子煤粉点火系统的工作原理、点火燃烧器功能、点火燃烧机理以及在上海吴泾热电厂2台1125t/h锅炉上的应用情况。总结了等离子煤粉点火装置和稳燃系统的安装、调试与日常运维经验。实践表明,等离子煤粉点火技术是一种节能、环保、快速升负荷的技术。锅炉点火燃油零消耗,既提高了煤粉燃烧的经济性,又减少了燃煤电厂的烟尘排放;既改善了厂区周边环境,又降低了生产成本。交流等离子煤粉点火系统的应用,可以获得较好的经济及社会效益。%The essay introduces operational principle of alternating plasma pulverized coal ignition system, the function of ignition burner, mechanization of ignition combustion and the application of plasma pulverized coal ignition combustion technology on two 1 125 t/h boilers in Shanghai Wujing Thermal Power Plant. It also makes a summary of installation, debugging and routine operational maintenance experience for plasma pulverized coal ignition device and stabilized combustion system. The practice proves that plasma pulverized coal ignition technology is a new technology with conservation of energy, environmental protection and quick power increasing. With ignition fuel oil zero consumption, it not only raises economical efficiency of pulverized coal burning, but also reduces smoke dust discharging in coal fired power plant, and improves power plant's surroundings as well as lowers the production cost effectively. The application of alternating plasma pulverized coal ignition system brings better economic and social benefits.

  9. Hydration of fly ash cement

    Energy Technology Data Exchange (ETDEWEB)

    Etsuo Sakai; Shigeyoshi Miyahara; Shigenari Ohsawa; Seung-Heun Lee; Masaki Daimon [Tokyo Institute of Technology, Tokyo (Japan). Department of Metallurgy and Ceramics Science, Graduate School of Science and Engineering

    2005-06-01

    It is necessary to establish the material design system for the utilization of large amounts of fly ash as blended cement instead of disposing of it as a waste. Cement blended with fly ash is also required as a countermeasure to reduce the amount of CO{sub 2} generation. In this study, the influences of the glass content and the basicity of glass phase on the hydration of fly ash cement were clarified and hydration over a long curing time was characterized. Two kinds of fly ash with different glass content, one with 38.2% and another with 76.6%, were used. The hydration ratio of fly ash was increased by increasing the glass content in fly ash in the specimens cured for 270 days. When the glass content of fly ash is low, the basicity of glass phase tends to decrease. Reactivity of fly ash is controlled by the basicity of the glass phase in fly ash during a period from 28 to 270 days. However, at an age of 360 days, the reaction ratios of fly ash show almost identical values with different glass contents. Fly ash also affected the hydration of cement clinker minerals in fly ash cement. While the hydration of alite was accelerated, that of belite was retarded at a late stage.

  10. Fusion characterization of biomass ash

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Teng [State Key Laboratory ofMultiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Zhongguancun North Second Street, Beijing 100190 (China); Sino-Danish Center for Education and Research, Beijing, 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Fan, Chuigang; Hao, Lifang [State Key Laboratory ofMultiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Zhongguancun North Second Street, Beijing 100190 (China); Li, Songgeng, E-mail: sgli@ipe.ac.cn [State Key Laboratory ofMultiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Zhongguancun North Second Street, Beijing 100190 (China); Song, Wenli [State Key Laboratory ofMultiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Zhongguancun North Second Street, Beijing 100190 (China); Lin, Weigang [State Key Laboratory ofMultiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Zhongguancun North Second Street, Beijing 100190 (China); Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)

    2016-08-20

    Highlights: • A novel method is proposed to analyze fusion characteristics of biomass ash. • T{sub m} can represent the severe melting temperature of biomass ash. • Compared with AFT, TMA is the better choice to analyze the fusion characteristics of biomass ash. - Abstract: The ash fusion characteristics are important parameters for thermochemical utilization of biomass. In this research, a method for measuring the fusion characteristics of biomass ash by Thermo-mechanical Analyzer, TMA, is described. The typical TMA shrinking ratio curve can be divided into two stages, which are closely related to ash melting behaviors. Several characteristics temperatures based on the TMA curves are used to assess the ash fusion characteristics. A new characteristics temperature, T{sub m}, is proposed to represent the severe melting temperature of biomass ash. The fusion characteristics of six types of biomass ash have been measured by TMA. Compared with standard ash fusibility temperatures (AFT) test, TMA is more suitable for measuring the fusion characteristics of biomass ash. The glassy molten areas of the ash samples are sticky and mainly consist of K-Ca-silicates.

  11. Electrodialytic treatment of fly ash

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Pedersen, Anne Juul; Kirkelund, Gunvor Marie

    Heavy metals are removed from the fly ashes by an electrodialytic treatment with the aim of up-grading the ashes for reuse in stead of disposal in landfill.A great potential for upgrading of bio- and waste incineration ashes by electrodialytic treatment exists. In the future, the applicability...

  12. Simulation of low-temperature plasma interaction with pulverized coal for incineration improvement

    Energy Technology Data Exchange (ETDEWEB)

    A. Askarova; E. Karpenko; V. Messerle; A. Ustimenko [Al-Farabi Kazakh National University, Almaty (Kazakhstan). Department of Physics

    2003-07-01

    Plasma activation promotes more effective and environmental friendly low-grade coals incineration. The work presents numerical modeling results of plasma ignition, gasification and thermochemical preparation of a pulverized coal for incineration at power boilers. Thermodynamic code TERRA allows calculating products compound of plasma activated pulverized coal depended on temperature, pressure and plasma source power. Considering plasma source kinetic code PLASMA-COAL gives initial data for 3D-modeling of power boilers furnaces by FLOREAN code. 5 refs., 13 figs., 5 tabs.

  13. The effect of low-NOx combustion on residual carbon in fly ash and its adsorption capacity for air entrainment admixtures in concrete

    DEFF Research Database (Denmark)

    Pedersen, Kim Hougaard; Jensen, Anker Degn; Dam-Johansen, Kim

    2010-01-01

    been combusted in an entrained flow reactor to test the impact of changes in operating conditions and fuel type on the AEA adsorption of ash and NOx formation. Increased oxidizing conditions, obtained by improved fuel-air mixing or higher excess air, decreased the AEA requirements of the produced ash...

  14. Influence of the gray gases number in the weighted sum of gray gases model on the radiative heat exchange calculation inside pulverized coal-fired furnaces

    Directory of Open Access Journals (Sweden)

    Crnomarković Nenad Đ.

    2016-01-01

    Full Text Available The influence of the number of gray gases in the weighted sum in the gray gases model on the calculation of the radiative heat transfer is discussed in the paper. A computer code which solved the set of equations of the mathematical model describing the reactive two-phase turbulent flow with radiative heat exchange and with thermal equilibrium between phases inside the pulverized coal-fired furnace was used. Gas-phase radiative properties were determined by the simple gray gas model and two combinations of the weighted sum of the gray gases models: one gray gas plus a clear gas and two gray gases plus a clear gas. Investigation was carried out for two values of the total extinction coefficient of the dispersed phase, for the clean furnace walls and furnace walls covered by an ash layer deposit, and for three levels of the approximation accuracy of the weighting coefficients. The influence of the number of gray gases was analyzed through the relative differences of the wall fluxes, wall temperatures, medium temperatures, and heat transfer rate through all furnace walls. The investigation showed that there were conditions of the numerical investigations for which the relative differences of the variables describing the radiative heat exchange decrease with the increase in the number of gray gases. The results of this investigation show that if the weighted sum of the gray gases model is used, the complexity of the computer code and calculation time can be reduced by optimizing the number of gray gases. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in-house developed software tools

  15. A FUEL-RICH PRECOMBUSTOR. FIELD EVALUATION OF LOW-EMISSION COAL BURNER TECHNOLOGY ON UTILITY BOILERS - VOLUME IV. ALTERNATE CON- CEPTS FOR SOX, NOX, AND PARTICULATE EMISSIONS CONTROL FROM

    Science.gov (United States)

    The report gives results a study of the use of precombustors for the simultaneous control of S02, NOx, and ash emissions from coal combustion. In Phase 1, exploratory testing was conducted on a small pilot scale--293 kW (million Btu/hr)-pulverized-coal-fired precombustor to ident...

  16. The normalised wildfire ash index (NWAI): a remote sensing approach for quantifying post-wildfire ash loads

    Science.gov (United States)

    Chris, Chafer; Doerr, Stefan; Santin, Cristina

    2017-04-01

    The impacts of wildfire ash, the powdery residue from fuel burning, on post-fire ecosystems are many and diverse. Ash is a source of nutrients and can help the recovery of vegetation. It can also contain substantial amounts of recalcitrant carbon and thus contribute to long-term carbon storage. In its initial state, the ash layer on the ground can protect the bare soil, mitigating post-fire water erosion by runoff. However, when the adsorbent capability of this layer is exceeded, ash can be transported into the hydrological network and be a major contributor to water contamination. Ash can also contribute to post-fire mass movements such as debris flows. The eco-hydro-geomorphic impacts of ash on post-fire ecosystems are therefore important, but remain poorly quantified. A fundamental step in that direction is the understanding of ash production and distribution at the landscape scale, which would allow incorporating ash as a key parameter into post-fire risk models. We have developed a new spectral index (NWAI) using Landsat imagery to model the spatial distribution of ash loads in the post-fire landscape. It was developed based on a severe wildfire that burnt 13,000 ha of dry eucalyptus forest near Sydney and has also been tested for a forested area burnt by the catastrophic 2009 Black Saturday fires near Melbourne. Although ecosystem and fire characteristics differed substantially between the Sydney and Melbourne fires, our NWAI index performs well. In this contribution we will discuss the (i) the principles of the NWAI and (ii) its potential for pollution risk forecasting.

  17. A Study of Anti-seepage Design for Ash Area of Fossil Fuel Power Plant%燃煤电厂干式贮灰场防渗设计探讨

    Institute of Scientific and Technical Information of China (English)

    丁海容; 饶俊勇

    2011-01-01

    干式贮灰场可能引起的环保问题主要有对地下水、地表水、扬尘、噪声等,其中对地下水的影响往往更严重.对于式贮灰场进行防渗处理,是避免污染地下水环境,达到环保标准的重要方法.以此为思路,探讨了灰场可能污染方式、干灰场防渗的规定、作法,并对扩建灰场的防渗问题进行了深入探讨.%Problems caused by a dry ash disposal area include the pollution of underground water, the pollution of ground water, the pollution of fugitive dust and noise during construction, of which the pollution of underground water is the most serious hazard. To prevent underground water from being contaminated and to meet the environmental standard, anti-seepage system is the important design for dry ash disposal area. Possible pollution types, environmental standards and practice and anti-seepage system design for extensive ash disposal area are discussed in the paper.

  18. Co-Firing Oil Shale with Coal and Other Fuels for Improved Efficiency and Multi-Pollutant Control

    Energy Technology Data Exchange (ETDEWEB)

    Robert A. Carrington; William C. Hecker; Reed Clayson

    2008-06-01

    Oil shale is an abundant, undeveloped natural resource which has natural sorbent properties, and its ash has natural cementitious properties. Oil shale may be blended with coal, biomass, municipal wastes, waste tires, or other waste feedstock materials to provide the joint benefit of adding energy content while adsorbing and removing sulfur, halides, and volatile metal pollutants, and while also reducing nitrogen oxide pollutants. Oil shale depolymerization-pyrolysis-devolatilization and sorption scoping studies indicate oil shale particle sorption rates and sorption capacity can be comparable to limestone sorbents for capture of SO2 and SO3. Additionally, kerogen released from the shale was shown to have the potential to reduce NOx emissions through the well established “reburning” chemistry similar to natural gas, fuel oil, and micronized coal. Productive mercury adsorption is also possible by the oil shale particles as a result of residual fixed-carbon and other observed mercury capture sorbent properties. Sorption properties were found to be a function particle heating rate, peak particle temperature, residence time, and gas-phase stoichmetry. High surface area sorbents with high calcium reactivity and with some adsorbent fixed/activated carbon can be produced in the corresponding reaction zones that exist in a standard pulverized-coal or in a fluidized-bed combustor.

  19. MGT 330 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    alfoniz

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MGT 330 Week 1 Individual Assignment Functions of Management Paper (Ash) MGT 330 Week 1 DQ 1 (Ash) MGT 330 Week 1 DQ 2 (Ash) MGT 330 Week 1 DQ 3 (Ash) MGT 330 Week 1 Summary (Ash) MGT 330 Week 2 Team Assignment External Internal Factors Paper (Ash) MGT 330 Week 2 Individual Assignment Delegation (Ash) MGT 330 Week 2 Summary (Ash) MGT 330 Week 2 DQ 1 (Ash) MGT 330 Week 2 DQ 2 (Ash) MGT 330 W...

  20. Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments

    Energy Technology Data Exchange (ETDEWEB)

    Motlep, Riho, E-mail: riho.motlep@ut.ee [Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Sild, Terje, E-mail: terje.sild@maaamet.ee [Estonian Land Board, Mustamaee tee 51, 10621 Tallinn (Estonia); Puura, Erik, E-mail: erik.puura@ut.ee [Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu (Estonia); Kirsimaee, Kalle, E-mail: kalle.kirsimae@ut.ee [Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu (Estonia)

    2010-12-15

    Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years.

  1. DETERMINATION OF GRANULOMETRIC COMPOSITION OF PULVERIZED COAL BY AUTOMATED SYSTEM

    Directory of Open Access Journals (Sweden)

    A. S. Chernenko

    2015-01-01

    Full Text Available The method of granulometric composition determination of dry powders by a shadow method in the automated system of determination of quantitative structure is described. The granulometric analysis of coal-dust fuel particles is carried out. Comparison with results of digital microscopy allowed to establish a variety of used method advantages.

  2. FUNDAMENTAL INVESTIGATION OF FUEL TRANSFORMATIONS IN PULVERIZED COAL COMBUSTION AND GASIFICATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Joseph Calo; Thomas Fletcher; Alan Sayre

    2004-01-01

    The goal of this project is to carry out the necessary experiments and analyses to extend leading submodels of coal transformations to the new conditions anticipated in next-generation energy technologies. During the first two projects years, significant progress was made on most of the tasks, as described in detail in the two previous annual reports. In the current third annual report, we report in detail on the BYU task on the properties and intrinsic reactivities of chars prepared at high-pressure. A flat-flame burner was used in a high pressure laminar flow facility to conduct high temperature, high heating rate coal pyrolysis experiments. Heating rates were approximately 10{sup 5} K/s, which is higher than in conventional drop tube experiments. Char samples from a Pitt No.8 coal and lignite were collected at 1300 C at 1, 6, 10, and 15 atm. Swelling ratios of the lignite were less than 1.0, and only about 1.3 for the Pitt No.8 coal. All coals showed slight increases in swelling behavior as pressure increased. The swelling behavior observed for the Pitt No.8 coal at each pressure was lower than reported in high pressure drop tube experiments, indicating the effect of heating rate on particle swelling. This heating rate effect was similar to that observed previously at atmospheric pressure. SEM photos revealed that bituminous coal has large physical structure transformations, with popped bubbles due to the high heating rate. TGA char oxidation reactivities were measured at the same total pressure as the char preparation pressure. The general trend was that the TGA reactivity on a gram per gram available basis decreased for both Pitt No.8 and Knife River lignite coal chars with increasing char formation pressure. The Pitt No.8 char intrinsic activation energy and oxygen reaction order remained relatively constant with increasing pressure. This new data provides some of the only information available on the morphology, structure, and reactivity of chars prepared in high pressure flames.

  3. Coal selection for NO{sub x} reduction in pulverized fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gibbins, J.R.; Lockwood, F.C.; Man, C.K.; Williamson, J.; Hesselman, G.J.; Downer, B.M.; Skorupska, N.M. [Imperial College of Science, Technology and Medicine, London (United Kingdom)

    1995-12-31

    A major factor affecting a coal`s performance in air-staged low-NO{sub x} burners is the amount of nitrogen remaining in the char after devolatilisation. Current standard proximate devolatilisation tests do not apply realistic heating conditions for PF combustion, but a recently-developed high-temperature wire-mesh reactor now allows relatively simple captive-sample measurements at heating rates of 10{sup 4} K/s. Char nitrogen data is reported for devolatilisation temperatures from 400{degree}C to 1800{degree}C, including values for a range of UK and world-traded coals for which NO{sub x} measurements from three full-scale low-NO{sub x} utility plants and/or a pilot combustor are available. The most general correlation between char nitrogen and combustion NO{sub x} is observed for a peak preparation temperature of 1800{degree}C with 0.15 s (or 2 s) hold time or 1600{degree}C with 2 s hold, conditions which give the maximum release of nitrogen from the char. 18 refs., 8 figs.

  4. Danish Experiences with Deposit Probe Measurements in Grate and Pulverized Fuel Biomass Power Boilers

    DEFF Research Database (Denmark)

    Hansen, Stine Broholm; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2012-01-01

    Several measuring campaigns with focus on deposition behavior have been conducted at full-scale power plants firing biomass in Denmark. These campaigns have been reviewed in this work. The focus is the obtained experiences on deposit formation, shedding and chemistry. When comparing results from...

  5. Deposit Probe Measurements in Danish Grate and Pulverized Fuel Biomass Power Boilers

    DEFF Research Database (Denmark)

    Hansen, Stine Broholm; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2012-01-01

    Several measuring campaigns with focus on deposition behavior have been conducted at full-scale power plants firing biomass in Denmark. These measuring campaigns have been reviewed in this work. The focus of the review is the obtained experiences on deposit formation, chemistry and shedding...

  6. A Model for Nitrogen Chemistry in Oxy-Fuel Combustion of Pulverized Coal

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Hansen, Stine; Toftegaard, Maja Bøg

    2011-01-01

    involving both char and soot. Here, the tar yield of the volatiles is mainly converted to soot and H2, limiting the concentration of hydrocarbons and thereby the importance of gas-phase removal of NO. Our work emphasizes the need for accurate descriptions of mixing, volatile composition (fate of tar...

  7. Pyrometric fuel particle measurements in pressurised reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Joutsenoja, T. [Tampere Univ. of Technology (Finland)

    1996-12-01

    A fiberoptic two-colour pyrometric technique for fuel particle temperature and size measurement is modified and applied to three pressurized reactors of different type in Finland, Germany and France. A modification of the pyrometric method for simultaneous in situ measurement of the temperature and size of individual pulverized coal particles at the pressurized entrained flow reactor in Jyvaeskylae was developed and several series of measurements were made. In Orleans a fiberoptic pyrometric device was installed to a pressurised thermogravimetric reactor and the two-colour temperatures of fuel samples were measured. Some results of these measurements are presented. The project belongs to EU`s Joule 2 extension research programme. (author)

  8. Taste acceptability of pulverized brand-name and generic drugs containing amlodipine or candesartan.

    Science.gov (United States)

    Uestuener, Peter; Ferrarini, Alessandra; Santi, Maristella; Mardegan, Chiara; Bianchetti, Mario G; Simonetti, Giacomo D; Milani, Gregorio P; Lava, Sebastiano A G

    2014-07-01

    Trials with pulverized brand-name antihypertensive drugs suggest that, from the perspective of taste acceptability, crushed candesartan, chlortalidon, hydrochlorothiazide, lercanidipine and lisinopril should be preferred to pulverized amlodipine, atenolol, bisoprolol, enalapril, irbesartan, losartan, ramipril, telmisartan and valsartan. Brand-name antihypertensive drugs and the corresponding generic medicines have never been compared with respect to their taste acceptability. We therefore investigated among healthy health care workers the taste acceptability of a pulverized 1 mg-test dose of the brand-name and two generics containing either the dihydropyridine calcium-channel blocker amlodipine (Norvasc(®), Amlodipin-Mepha(®) and Amlodipin Pfizer(®)) or the angiotensin receptor antagonist candesartan (Atacand(®), Cansartan-Mepha(®) and Pemzek(®)). For this purpose, a smiley-face scale depicting four degrees of pleasure was used. Between November and December 2013, the taste test was performed among 19 nurses (15 female and 4 male subjects) and 12 physicians (5 female and 7 male subjects) aged between 25 and 49 years. Pulverized brand-names and generics containing either amlodipine or candesartan did not differ with respect to their taste acceptability.

  9. CFD simulation and experimental validation of co-combustion of chicken litter and MBM with pulverized coal in a flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Heikkinen, J.M.; Venneker, B.C.H.; di Nola, G.; de Jong, W.; Spliethoff, H. [Energy Technology section, Delft University of Technology, Leeghwaterstraat 44, NL-2628 CA Delft (Netherlands)

    2008-09-15

    The influence of co-combustion of solid biomass fuels with pulverized coal on burnout and CO emissions was studied using a flow reactor. The thermal input on a fuel feeding basis of the test rig was approximately 7 kW. Accompanied with the measurements, a reactor model using the CFD code AIOLOS was set up and first applied for two pure coal flames (with and without air staging). Reasonable agreement between measurements and simulations was found. An exception was the prediction of the CO concentration under sub-stoichiometric conditions (primary zone). As model input for the volatile matter release, the HTVM (high temperature volatile matter as defined by IFRF [IFRF, www.handbook.ifrf.net/handbook/glossary.html. ]) was used. Furthermore, a relatively slow CO oxidation rate obtained from the literature and the ERE (Extended Resistance Equation) model for char combustion were selected. Furthermore, the model was used for simulating co-firing of coal with chicken litter (CL) and meat and bone meal (MBM). The conditions applied are relevant for future co-firing practice with high thermal shares of secondary fuels (larger than 20%). The major flue gas concentrations were quite well described, however, CO emission predictions were only qualitatively following the measured trends when O{sub 2} is available and severely under-predicted under substoichiometric conditions. However, on an engineering level of accuracy, and concerning burnout, this work shows that co-combustion of the fuels can reasonably well be described with coal combustion sub-models. (author)

  10. Ash reduction system using electrically heated particulate matter filter

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI; Paratore, Jr., Michael J; He, Yongsheng [Sterling Heights, MI

    2011-08-16

    A control system for reducing ash comprises a temperature estimator module that estimates a temperature of an electrically heated particulate matter (PM) filter. A temperature and position estimator module estimates a position and temperature of an oxidation wave within the electrically heated PM filter. An ash reduction control module adjusts at least one of exhaust flow, fuel and oxygen levels in the electrically heated PM filter to adjust a position of the oxidation wave within the electrically heated PM filter based on the oxidation wave temperature and position.

  11. Fuel flexible fuel injector

    Science.gov (United States)

    Tuthill, Richard S; Davis, Dustin W; Dai, Zhongtao

    2015-02-03

    A disclosed fuel injector provides mixing of fuel with airflow by surrounding a swirled fuel flow with first and second swirled airflows that ensures mixing prior to or upon entering the combustion chamber. Fuel tubes produce a central fuel flow along with a central airflow through a plurality of openings to generate the high velocity fuel/air mixture along the axis of the fuel injector in addition to the swirled fuel/air mixture.

  12. CFD analysis of the pulverized coal combustion processes in a 160 MWe tangentially-fired-boiler of a thermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cristiano V. da; Beskow, Arthur B. [Universidade Regional Integrada do Alto Uruguai e das Misses (LABSIM/GEAPI/URI), Erechim, RS (Brazil). Dept. de Engenharia e Ciencia da Computacao. Grupo de Engenharia Aplicada a Processos Industriais], Emails: cristiano@uricer.edu.br, Arthur@uricer.edu.br; Indrusiak, Maria Luiza S. [Universidade do Vale do Rio dos Sinos (UNISINOS), Sao Leopoldo, RS (Brazil). Programa de Engenharia Mecanica], E-mail: sperbindrusiak@via-rs.net

    2010-10-15

    The strategic role of energy and the current concern with greenhouse effects, energetic and exegetic efficiency of fossil fuel combustion greatly enhance the importance of the studies of complex physical and chemical processes occurring inside boilers of thermal power plants. The state of the art in computational fluid dynamics and the availability of commercial codes encourage numeric studies of the combustion processes. In the present work the commercial software CFX Ansys Europe Ltd. was used to study the combustion of coal in a 160 MWe commercial thermal power plant with the objective of simulating the operational conditions and identifying factors of inefficiency. The behavior of the flow of air and pulverized coal through the burners was analyzed, and the three-dimensional flue gas flow through the combustion chamber and heat exchangers was reproduced in the numeric simulation. (author)

  13. Use of fly ash with no water consumption for cold regions transportation infrastructure

    Institute of Scientific and Technical Information of China (English)

    Gokhan Baykal

    2015-01-01

    The construction period in cold regions is very short due to problems related to excavation and use of frozen soils in embankment construction, which leads to excessive deformations upon thawing. Also, handling of compaction water is critical due to freezing temperatures. Coalburning thermal power plants are very common in cold regions to supply electricity. The inorganic part of the pulverized coal after burning produces fly ash, which is available in large volumes. Due to excavation difficulties and the poor engineering behavior of frozen soils in cold regions, the utilization of fly ash when it is readily available must be promoted. Any construction technique which utilizes alternative materials like fly ash and minimizes water consumption has a potential to extend the short construction season and even allow service and maintenance during extreme weather conditions. This paper presents two potential techniques to solve the moisture affinity of silt-sized materials like fly ash. One technique involves in-plant production of fly ash pellets using cold-bonding pelletization to manufacture aggregates of up to 40,000-μm diameter from 15-to 60-μm-diameter fly ash grains. Large disc pelletizers have annual production capacities of up to one million ton at a reasonable cost. The product has adequate strength for embankment construction even when no water is used and no compaction is applied. The second technique is an in situ mixing technique which uses snow instead of compaction water for fly ash. The snow is the main element in this technique to compact the embankment. Water is needed for the hydration reactions to form cementitious minerals in fly ash. The slower the hydration reaction, the greater the crystal growth of cementitious minerals. In the proposed technique, in situ snow is mixed with fly ash and is compacted on-site. The temperature increase due to the hydration reaction of fly ash upon contact with snow crystals provides water for continued long

  14. Ecological and economic solution for removing and dumping the slag and ash from coal-fired low capacity boilers

    Energy Technology Data Exchange (ETDEWEB)

    Dumitru Gardan; Laurentiu Maier; Nistor Bujdei; Maria Gardan [Institute of Power Studies and Design, Timisoara (Romania)

    2003-07-01

    The removal of ash and slags from fossil-fuel power plants and their transport to and storage on dumps are discussed. A new dense slurry ash removal process developed by IPSE and Termoelectrica is described. This was successfully tested at Timisoara coal-fired power plant, Romania. 2 figs., 1 tab.

  15. [An investigation of the formation of] polycyclic aromatic hydrocarbon (PAH) emissions when firing pulverized coal in a bench-scale drop tube reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pisupati, S.V.; Wasco, R.S.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States). Combustion Lab.

    1998-12-31

    The Clean Air Act Amendments (CAAA) of 1990 contain provisions which will set standards for the allowable emissions of 188 analytes designated as hazardous air pollutants (HAPs). This list of HAPs was used to establish an initial list of source categories for which EPA would be required to establish technology-based emission standards, which would result in regulated sources sharply reducing routine emissions of toxic air pollutants. Polycyclic organic matter (POM) has also been referred to as polynuclear or polycyclic aromatic compounds (PACs). Nine major categories of POM have been defined by EPA. The study of organic compounds from coal combustion is complex and the results obtained so far are inconclusive with respect to emission factors. The most common organic compounds in the flue gas of coal-fired power plants are polycyclic aromatic hydrocarbons (PAHs). Furthermore, EPA has specified 16 PAH compounds as priority pollutants. These are naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene, and dibenz[ah]anthracene. Penn State`s Combustion Laboratory is equipped to collect and analyze the HAPs in the flue gas from fossil fuels combustion. The overall objective of this study was to examine the effect of unit temperature on PAH emissions. A Modified Method 5 sampling train was used to isokinetically collect samples at desired locations in flue gas streams. The collected sample can be separated into solid, condensed liquid and gaseous phases. The PAHs of interest are extracted from the collected sample, concentrated, then separated and quantified by gas chromatography/mass spectrometry (GC/MS). This study was conducted using a bench-scale drop-tube reactor (DTR). The fuel selected for this study was a Middle Kittanning seam coal pulverized to 80% passing US Standard 200 mesh (commonly

  16. Volcanic ash melting under conditions relevant to ash turbine interactions.

    Science.gov (United States)

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B

    2016-03-02

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines.

  17. Influence of the co-firing on the leaching of trace pollutants from coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Maria Izquierdo; Natalia Moreno; Oriol Font; Xavier Querol; Esther Alvarez; Diano Antenucci; Henk Nugteren; Yolanda Luna; Constantino Fernandez-Pereira [Institute of Earth Sciences ' Jaume Almera' (CSIC), Barcelona (Spain)

    2008-08-15

    The (co)-firing of low-cost alternative fuels is expected to increase in the forthcoming years in the EU because of the economic and environmental benefits provided by this technology. This study deals with the impact of the different coal/waste fuel ratio of the feed blend on the mineralogy, the chemical composition and especially on the leaching properties of fly ash. Different blends of coal, petroleum coke, sewage sludge, wood pellets, coal tailings and other minor biomass fuels were tested in PCC (pulverised coal combustion) and FBC (fluidized bed combustion) power plants. The co-firing of the studied blends did not drastically modify the mineralogy, bulk composition or the overall leaching of the fly ash obtained. This suggests that the co-firing process using the alternative fuels studied does not entail significant limitations in the re-use or management strategies of fly ash. 34 refs., 4 figs., 3 tabs.

  18. MGT 401 ASH Course Tutorial / Tutorialoutlet

    OpenAIRE

    kennith

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   MGT 401 Week 1 Individual Assignment Strategic Management Process Paper (Ash) MGT 401 Week 1 Class Activity Week 1 (Ash) MGT 401 Week 1 DQ 1 (Ash) MGT 401 Week 1 DQ 2 (Ash) MGT 401 Week 2 Learning Team Business Model Comparison Example (Ash) MGT 401 Week 2 DQ 1 (Ash) MGT 401 Week 2 DQ 2 (Ash) MGT 401 Week 2 Class Activity (Ash) MGT 401 Week 3 Individual Assignment Business Plan Evaluation (Ash) ...

  19. Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

    Science.gov (United States)

    Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

    2013-12-01

    Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to

  20. Ash in the Soil System

    Science.gov (United States)

    Pereira, P.

    2012-04-01

    Ash is the organic and inorganic residue produced by combustion, under laboratory and field conditions. This definition is far away to be accepted. Some researchers consider ash only as the inorganic part, others include also the material not completely combusted as charcoal or biochar. There is a need to have a convergence about this question and define clear "what means ash". After the fire and after spread ash onto soil surface, soil properties can be substantially changed depending on ash properties, that can be different according to the burned residue (e.g wood, coal, solid waste, peppermill, animal residues), material treatment before burning, time of exposition and storage conditions. Ash produced in boilers is different from the produced in fires because of the material diferent propertie and burning conditions. In addition, the ash produced in boilers is frequently treated (e.g pelletization, granulation, self curing) previously to application, to reduce the negative effects on soil (e.g rapid increase of pH, mycorrhiza, fine roots of trees and microfauna). These treatments normally reduce the rate of nutrients dissolution. In fires this does not happen. Thus the implications on soil properties are logically different. Depending on the combustion temperature and/or severity, ash could have different physical (e.g texture, wettability) and chemical properties (e.g amount and type of total and leached nutrients) and this will have implications on soil. Ash can increase and decrease soil aggregation, wettablity and water retention, bulk density, runoff and water infiltration. Normally, ash increases soil pH, Electrical Conductivity, and the amount of some basic nutrients as calcium, magnesium, sodium and potassium. However it is also a potential source of heavy metals, especially if ash pH is low. However the effect of ash on soil in space and time depends especially of the ash amount and characteristics, fire temperature, severity, topography, aspect

  1. Ash Aggregates in Proximal Settings

    Science.gov (United States)

    Porritt, L. A.; Russell, K.

    2012-12-01

    Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (sustained plume attended by concomitant production of pyroclastic density currents. The size and internal structure of the armoured lapilli provide constraints on the nature of the initial explosive phase of eruption at Kima'Kho. Their proximity to the vent also indicates rapid aggregation within the eruption plume. Within both sequences rapid aggregation of ash particles occurred in proximity to the vent. However, the conditions were substantially different leading to the production of armoured

  2. Dielectric properties of fly ash

    Indian Academy of Sciences (India)

    S C Raghavendra; R L Raibagkar; A B Kulkarni

    2002-02-01

    This paper reports the dielectric properties of fly ash. The dielectric measurements were performed as a function of frequency and temperature. The sample of fly ash shows almost similar behaviour in the frequency and temperature range studied. The large value of dielectric constant in the typical frequency range is because of orientation polarization and tight binding force between the ions or atoms in the fly ash. The sample of fly ash is of great scientific and technological interest because of its high value of dielectric constant (104).

  3. Utilization of ash fractions from alternative biofuels used in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaisen, L.; Hinge, J.; Christensen, I. (Danish Technological Inst., Aarhus (Denmark)); Dahl, J. (Force Technology, Broendby (Denmark)); Arendt Jensen, P. (DTU-CHEC, Kgs. Lyngby (Denmark)); Soendergaard Birkmose, T. (Dansk Landbrugsraadgivning, Landscentret, Aarhus (Denmark)); Sander, B. (DONG Energy, Fredericia (Denmark)); Kristensen, O. (Kommunekemi A/S, Nyborg (Denmark))

    2008-07-15

    It is expected, that demand for the traditional biomass resources wood and straw will increase over the next years. In other projects a number of agro industrial waste products has been tested and characterized as fuels for power plants. The annual production in Denmark of these fuels is estimated at roughly 400.000 tons of Dry Matter per year, so the potential is substantial. The agro industrial biomass products include: Grain screening waste, pea shells, soy waste, cocoa waste, sugar beet waste, sunflower waste, shea waste, coffee waste, olive waste, rice shell waste, potato waste, pectin waste, carrageen waste, tobacco waste, rape seed waste and mash from breweries. In the PSO project 5075, 5 different types of fuel pellets was produced, which were rendered suitable for combustion in power plants. In this project, ash is produced from the above mentioned 5 mixtures together with another 2 mixtures produced especially for this project. From the 5 mixtures from PSO 5075, ash is produced at Danish Technological Institute's slag analyzer. These ash products are rendered comparable to ash from grate fired boilers at power plants. The ash/slag from the combustion in the slag analyzer was then grinded - thus resulting in a total of 5 ash products. At DTU CHEC's Entrained Flow Reactor, ash products from the 5+2 mixtures were produced. These ash products are rendered comparable to ash produced form suspension fired boilers at power plants. For each of the 7 mixtures, bottom-, cyclone and filter ash was taken out separately resulting in a total of 21 ash samples. The produced ashes have been evaluated for their properties as directly applied fertilizer. Furthermore, scenarios have been set up to assess the feasibility in producing artificial fertilizer from the ash products, based on known processes. In the main components the content of Na, S, Cl and K is significantly higher in filter ashes, whereas the content of Mg, Al, Si and Ca is significantly lower. The

  4. FY 1999 report of the project on the waste-fueled power generation in the north area of Malaysia; 1999 nendo Malaysia hokubu chiiki gomi hatsuden project seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Penang Island, in the northern part of Malaysia, where the urbanization is well advanced and sites for waste disposal are scarce, was selected as a target area for the research on introduction of solid waste (henceforth called reuse) power generation system. About 500 tons of refuse are generated daily in Penang Island, and are disposed of in a coastal landfill site at Jelutong near the center of George Town, the state capital. Although the landfill site is already beyond its capacity, it is still in use because there are no other disposal sites in the island. For this reason, there is widespread concern about coastal environmental pollution. Therefore, the Municipal Council of Penang Island has studied feasibility of transferring refuse to a new landfill site at the peninsula side of Penang State across the Penang Bridge over the sea channel which separates the island and the peninsula. However, this transfer and landfill method has not been realized yet. In view of improvement of these situations regarding solid waste management is Penang Island, it is proposed in this report, as the result of the research, introduction of power generation system fueled already-accumulated refuse in this disposal site together with refuse to be collected every day. The study was started in September 1999 and was completed in March 2000. Japan Environmental Consultants, Ltd. investigated the present situation of solid waste management in Penang Island, analyzed refuse properties, and studied the refuse fueled power generation technology with the cooperation of SIRIM (Environmental and Energy Technology Centre) and PTM (Pusat Tenaga Malaysia, Malaysia Energy Centre) in Malaysia. In concrete, the research team established a scheme of an integrated system most suitable for the refuse treatment including refuse power generation in Penang Island, the famous resort of northern Malaysia, and studied its feasibility. The proposed system is combination of selective pulverizing classifiers

  5. Volcanic ash infrared signature: realistic ash particle shapes compared to spherical ash particles

    Directory of Open Access Journals (Sweden)

    A. Kylling

    2013-10-01

    Full Text Available The reverse absorption technique is often used to detect volcanic clouds from thermal infrared satellite measurements. From these measurements particle size and mass loading may also be estimated using radiative transfer modelling. The radiative transfer modelling usually assumes that the ash particles are spherical. We calculate thermal infrared optical properties of highly irregular and porous ash particles and compare these with mass- and volume-equivalent spherical models. Furthermore, brightness temperatures pertinent to satellite observing geometry are calculated for the different ash particle shapes. Non-spherical shapes and volume-equivalent spheres are found to produce a detectable ash signal for larger particle sizes than mass-equivalent spheres. The assumption of mass-equivalent spheres for ash mass loading estimates will underestimate the mass loading by several tens of percent compared to morphologically complex inhomogeneous ash particles.

  6. Volcanic ash infrared signature: realistic ash particle shapes compared to spherical ash particles

    Science.gov (United States)

    Kylling, A.; Kahnert, M.; Lindqvist, H.; Nousiainen, T.

    2013-10-01

    The reverse absorption technique is often used to detect volcanic clouds from thermal infrared satellite measurements. From these measurements particle size and mass loading may also be estimated using radiative transfer modelling. The radiative transfer modelling usually assumes that the ash particles are spherical. We calculate thermal infrared optical properties of highly irregular and porous ash particles and compare these with mass- and volume-equivalent spherical models. Furthermore, brightness temperatures pertinent to satellite observing geometry are calculated for the different ash particle shapes. Non-spherical shapes and volume-equivalent spheres are found to produce a detectable ash signal for larger particle sizes than mass-equivalent spheres. The assumption of mass-equivalent spheres for ash mass loading estimates will underestimate the mass loading by several tens of percent compared to morphologically complex inhomogeneous ash particles.

  7. Spreading dynamic of viscous volcanic ash in stimulated jet engine conditions

    Science.gov (United States)

    song, wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado

    2016-04-01

    The ingestion of volcanic ash is widely recognised as a potentially fatal hazard for aircraft operation. The volcanic ash deposition process in a jet turbine is potentially complex. Volcanic ash in the air stream enters the inner liners of the combustors and partially or completely melts under the flames up to 2000 °C, at which point part of the ash deposits in the combustor fuel nozzle. Molten volcanic particles within high energy airflow escape the combustor to enter the turbine and impact the stationary (e.g., inlet nozzle guide vanes) and rotating airfoils (e.g., first stage high-pressure turbine blades) at high speed (up to Mach 1.25) in different directions, with the result that ash may stick, flow and remain liquid or solidify. Thus, the wetting behaviour of molten volcanic ash particle is fundamental to investigate impingement phenomena of ash droplet on the surface of real jet engine operation. The topic of wetting has received tremendous interest from both fundamental and applied points of view. However, due to the interdisciplinary gap between jet engine engineering and geology science, explicit investigation of wetting behaviour of volcanic ash at high temperature is in its infancy. We have taken a big step towards meeting this challenge. Here, we experimentally and theoretically investigate the wetting behaviour of viscous volcanic ash over a wide temperature range from 1100 to 1550 °C using an improved sessile-drop method. The results of our experiment demonstrate that temperature and viscosity play a critical role in determining the wetting possibility and governing the spreading kinetics of volcanic ash at high temperatures. Our systemic analysis of spreading of molten volcanic ash systems allows us to report on the fundamental differences between the mechanisms controlling spreading of organic liquids at room temperature and molten volcanic ash droplets.

  8. Co-combustion of coal and sewage sludge: chemical and ecotoxicological properties of ashes.

    Science.gov (United States)

    Barbosa, Rui; Lapa, Nuno; Boavida, Dulce; Lopes, Helena; Gulyurtlu, Ibrahim; Mendes, Benilde

    2009-10-30

    The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal treatment have not been fully studied. Two combustion tests were performed in a fluidized bed combustor. Colombian coal was used as fuel in test A. A blend (1+1) of this coal and a stabilized SS (Biogran) was used in a second test B. Samples of the bottom and fly ashes trapped in two sequential cyclones were collected. The characterization of the ashes was focused on two main aspects: (1) the bulk content of a set of metals and (2) the characterization of eluates produced according to the European Standard leaching test EN 12457-2. The eluates were submitted to an ecotoxicological characterization for two bio-indicators. In what concerns the bulk content of ashes, both combustion tests have produced ashes with different compositions. The ashes formed during the co-combustion test have shown higher concentrations of metals, namely Cr, Cu, Ni, Pb, Zn and Fe for all ashes. The leaching test has shown low mobility of these elements from the by-products produced during the combustion and co-combustion tests. Cr and Cr(VI) were mainly detected in the eluates of the 1st cyclone ashes produced in both combustion tests and in the 2nd cyclone ashes produced in the co-combustion test. Considering the ecotoxicity assays, the eluates of bottom and fly ashes for both combustion and co-combustion tests have shown low ecotoxic levels. The micro-crustacean Daphnia magna was generally more sensitive than the bacterium Vibrio fischeri. CEMWE criterion has allowed to classify the bottom ashes for both combustion and co-combustion tests as non-toxic residues and the fly ashes collected in both cyclones as toxic.

  9. OPTIMIZED FUEL INJECTOR DESIGN FOR MAXIMUM IN-FURNACE NOx REDUCTION AND MINIMUM UNBURNED CARBON

    Energy Technology Data Exchange (ETDEWEB)

    SAROFIM, A F; LISAUSKAS, R; RILEY, D; EDDINGS, E G; BROUWER, J; KLEWICKI, J P; DAVIS, K A; BOCKELIE, M J; HEAP, M P; PERSHING, D

    1998-01-01

    Reaction Engineering International (REI) has established a project team of experts to develop a technology for combustion systems which will minimize NO x emissions and minimize carbon in the fly ash. This much need technology will allow users to meet environmental compliance and produce a saleable by-product. This study is concerned with the NO x control technology of choice for pulverized coal fired boilers,"in-furnace NOx control," which includes: staged low-NOx burners, reburning, selective non-catalytic reduction (SNCR) and hybrid approaches (e.g., reburning with SNCR). The program has two primary objectives: 1) To improve the performance of "in-furnace" NOx control, processes. 2) To devise new, or improve existing, approaches for maximum "in-furnace" NOx control and minimum unburned carbon. The program involves: 1) fundamental studies at laboratory- and bench-scale to define NO reduction mechanisms in flames and reburning jets; 2) laboratory experiments and computer modeling to improve our two-phase mixing predictive capability; 3) evaluation of commercial low-NOx burner fuel injectors to develop improved designs, and 4) demonstration of coal injectors for reburning and low-NOx burners at commercial scale. The specific objectives of the two-phase program are to: 1 Conduct research to better understand the interaction of heterogeneous chemistry and two phase mixing on NO reduction processes in pulverized coal combustion. 2 Improve our ability to predict combusting coal jets by verifying two phase mixing models under conditions that simulate the near field of low-NOx burners. 3 Determine the limits on NO control by in-furnace NOx control technologies as a function of furnace design and coal type. 5 Develop and demonstrate improved coal injector designs for commercial low-NOx burners and coal reburning systems. 6 Modify the char burnout model in REI's coal

  10. The Influencing Factors and Countermeasures for Self-ignition of Pulverized Coal Warehouse in Pulverized Coal Milling System%中间储仓式制粉系统粉仓自燃影响因素及对策

    Institute of Scientific and Technical Information of China (English)

    金帆; 李善涛

    2012-01-01

    针对中国石化上海石油化工股份有限公司热电部410 t/h煤粉炉在停炉抢修期间中间储仓式的粉仓内温度急剧上升、煤粉自燃的现象,分析了引起煤粉自燃的影响因素。根据实际情况,提出了煤粉自燃的防治措施和预防粉仓温度升高的方法。%Regarding the quick rising of temperature in the middle-warehouse pulverized coal house and self-ignition of pulverized coal in 410 t/a pulverized coal furnace during shutdown and emergency repairing period,the influencing factors causing self-ignition of pulverized coal were analyzed.Based on the practical situation,the preventions for self-ignition of pulverized coal and methods for preventing temperature in pulverized coal house from rising were raised.

  11. Influence of Bed Ash and Fly Ash Replacement in Mortars

    Directory of Open Access Journals (Sweden)

    S. L. Summoogum-Utchanah

    2015-03-01

    Full Text Available The study evaluates the influence of fly ash and bottom ash as partial cement substitutes in mortars by studying the particle size distribution, consistency, flow, fresh density, air content, compressive strength and flexural strength characteristics. The results revealed that fly ash and cement had relatively the same particle size distribution unlike bottom ash. In the fresh state, as the amount of pozzolans increased in the mixtures, the mortars showed an enhancement in workability, were susceptible to water loss by bleeding, and exhibited a decline in fresh density. The early strength gains of the fly ash samples were low but reached higher than the control after 28 days of curing. The flexural strength increased as the fly ash content rose to reach a maximum at 20 % replacement. However, the 2-day compressive strength of bottom ash samples was higher than the control but decreased after 28 days of curing while the flexural strength declined with addition of bottom ash except at 5 % substitution.

  12. Utilization of fly ash from coal-fired power plants in China

    Institute of Scientific and Technical Information of China (English)

    Da-zuo CAO; Eva SELIC; Jan-Dirk HERBELL

    2008-01-01

    The rapidly increasing demand for energy in China leads to the construction of new power plants all over the country. Coal, as the main fuel resource of those power plants, results in increasing problems with the disposal of solid residues from combustion and off gas cleaning. This investigation describes chances for the utilization of fly ash from coal-fired power plants in China. After briefly comparing the situation in China and Germany, the status of aluminum recycling from fly ash and the advantages for using fly ash in concrete products are introduced. Chemical and physical analyses of Chinese fly ash samples, e.g., X-ray diffraction (XRD), ICP (Inductive Coupled Plasma) and particle size analysis, water requirement, etc. are presented. Reasonable amounts of aluminum were detected in the samples under investigation, but for recovery only sophisticated procedures are available up to now. Therefore, simpler techniques are suggested for the first steps in the utilization of Chinese fly ash.

  13. Circulating fluidized bed combustion ash characterization. The case of the Provence 250 MW unit

    Energy Technology Data Exchange (ETDEWEB)

    Lecuyer, I.; Leduc, M. [Electricite de France (EDF), 78 - Chatou (France). Direction des Etudes et Recherches; Lefevre, R.; Ausset, P. [Paris-12 Univ., Creteil (France). Lab. Interuniversitaire des Systemes Atmospheriques

    1997-05-01

    The Provence 250 MW Circulating Fluidized Bed Combustion Unit (Gardanne, France) is burning a high sulfur (2 to 4%), high ash content (30%) local lignite. This peculiar fuel already contains about 15% of CaO which allows it to capture the sulfur dioxide in situ without adding any complementary sorbent. The ash chemical composition (bed ash and ESP ash) that reflects the particularities of the coal is presented. SEM and DRX observations confirm the presence of anhydrite CaSO{sub 4}, lime, CaS, quartz and traces of hematite. Most of particles are roughly-shaped but microspheres can also be detected in fly ash. The very high sulfate content may be worrying for the environment in disposals. Hardened samples do not seem to retain compounds from leaching: high quantities of calcium and sulfates are still leached from these crushed samples. (author) 10 refs.

  14. Electrodialytic remediation of fly ash from co-combustion of wood and straw

    DEFF Research Database (Denmark)

    Chen, Wan; Jensen, Pernille Erland; Ottosen, Lisbeth M.

    2015-01-01

    The heavy metal content in fly ash from biomass combustion, such as straw, wood and sludge, often needs reducing before the ash can be used as fertilizer for agricultural land or as a component in the production of construction materials. In this study, fly ash from a boiler fueled with wood chips...... and straw was treated either by electrodialytic remediation (EDR) directly or by a combination of EDR and pre-wash with distilled water to investigate the possibilities of reducing the heavy metal content and reusing nutrients as fertilizer and bulk material in construction materials. Different experimental....../pre-wash-EDR treated ash mainly contained quartz, and the X-ray diffraction (XRD) peaks of K salts had disappeared. This shows that the potassium fertilizer potential was lost in the treated ashes, but the quartz mineral is beneficial in construction materials, such as ceramics. The K fertilizer could be recovered...

  15. Development of metabarcoding for tracking changes of soil fauna community under stress by application of ash

    DEFF Research Database (Denmark)

    Qin, J; de Groot, G.A.; Hansen, L. H.

    developed. We therefore will start out by comparing the morphospecies approach with three molecular approaches, differing in the types of DNA extracted from soil samples: total soil DNA, extracellular DNA and DNA gained from animals collected from the soil. In order to target all faunal groups, we use a set......Ash is a waste product from combustion of bio-fuel in power plants. Application of ash on soil ensures nutrient recycling, but detrimental ecotoxicological consequences may arise since ash is a complex mixture that may contain compounds affecting soil invertebrates and their food and habitat...... condition. Here, we study the effects of ash on the abundance and composition of the soil fauna community. Over time, we will compare control plots with plots receiving three different concentrations of ash. Targeting soil fauna community includes protozoa, nematodes, enchytraeids, collembolans, mites...

  16. HIS 103 ASH course tutorial/tutorialoutlet

    OpenAIRE

    NARESH 1

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com   HIS 103 Week 1 DQ 1 (Transition to Agriculture) (Ash) HIS 103 Week 1 DQ 2 (Early Complex Societies) (Ash) HIS 103 Week 1 Quiz (Ash) HIS 103 Week 1 Assignment (Ash) HIS 103 Week 2 Assignment Greco Roman Influence Paper (Ash) HIS 103 Week 2 DQ 1 Chinese Social and Political Order Systems (Ash) HIS 103 Week 2 DQ 2 Caste System (Ash) HIS 103 Week 2 Quiz (Ash) HIS 103 Week 3 Assignment Black Death Dra...

  17. Cold Gas-particle Flows in a New Swirl Pulverized-coal Burner by PDPA Measurement

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new type of swirl burner has been developed to stabilize pulverized-coal combustion by burning different types of coal at different loads and to reduce NOx formation during combustion. The burner uses a device to concentrate the coal powder in the primary-air tube that divides the primary coal-air into two streams with different pulverized-coal concentrations. This paper reports the measurement of gas-particle flows at the exit of the different swirl burners using a 3-D Phase Doppler Particle Anemometer (PDPA). The effect of different geometrical configurations on the two-phase flow field is studied. The results that give the two-phase flow fields and particle concentrations show the superiority of the new swirl burner.

  18. XRF Analysis of mineralogical matrix effects and differences between pulverized and fused ferromanganese slag

    Directory of Open Access Journals (Sweden)

    VALENTINA ZIVANOVIC

    2011-06-01

    Full Text Available Determination and analysis is only as good as the sample preparation that preceded it. Even the most sophisticated analysis is worthless if it follows sloppy sampling and poor preparation. Whether one does plasma emission, infrared or X-ray fluorescence or another spectroscopic technique, it is essential to get reproducible and accurate analysis. This paper shows the effect of mineralogical matrix differences in quantitative measurements by XRF of the main elements (Al, Ca, Mg, Si, Mn and K as oxides of ferromanganese alloy slag. Fused and pulverized slag show a significant difference in XRF microstructure, micro heterogeneity and mineralogy although the results of measurements between pulverized and fused slag, expressed as a percentage of the main elements, is not different. Other analytical techniques such as ICP-OES and classical gravimetric and titrimetric were also used for checking the XRF calibration accuracy

  19. Emerald Ash Borer (Coleoptera: Buprestidae)

    Science.gov (United States)

    The emerald ash borer, Agrilus planipennis Fairmaire, is an invasive beetle from Asia that has caused large scale ash (Fraxinus spp.) mortality in North America. This book chapter reviews the taxonomy, biology, life history of this invasive pest and its associated natural enemies in both its native ...

  20. Leaching from biomass combustion ash

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2014-01-01

    The use of biomass combustion ashes for fertilizing and liming purposes has been widely addressed in scientific literature. Nevertheless, the content of potentially toxic compounds raises concerns for a possible contamination of the soil. During this study five ash samples generated at four...

  1. Recycling municipal incinerator fly- and scrubber-ash into fused slag for the substantial replacement of cement in cement-mortars.

    Science.gov (United States)

    Lee, Tzen-Chin; Rao, Ming-Kang

    2009-06-01

    Fly- and scrubber-ash (weight ratio of approximately 1:3) from municipal solid waste incinerators (MSWI) are a major land-fill disposal problem due to their leaching of heavy metals. We uniformly mixed both types of ash with optimal amounts of waste glass frit, which was then melted into a glassy slag. The glassy slag was then pulverized to a particle size smaller than 38microm for use as a cement substitute (20-40% of total cement) and blended with sand and cement to produce slag-blended cement-mortar (SCM) specimens. The toxicity characteristics of the leaching procedure tests on the pulverized slag samples revealed that the amount of leached heavy metals was far below regulatory thresholds. The compressive strength of the 28-day cured SCM specimens was comparable to that of ordinary Portland cement mortars, while the compressive strength of specimens cured for 60 or 90 days were 3-11% greater. The observed enhanced strength is achieved by Pozzolanic reaction. Preliminary evaluation shows that the combination of MSWI fly- and scrubber-ash with waste glass yields a cost effective and environmentally friendly cement replacement in cement-mortars.

  2. Separation and characterization of magnetic fractions from waste-to-energy bottom ash with an emphasis on the leachability of heavy metals.

    Science.gov (United States)

    Wei, Yunmei; Mei, Xiaoxia; Shi, Dezhi; Liu, Guotao; Li, Li; Shimaoka, Takayuki

    2017-06-01

    Magnetic fractions were extracted from pulverized waste-to-energy (WTE) bottom ashes using a combined wet-dry extraction method. The resulting magnetic and non-magnetic fractions were subjected to compositional, mineralogical, and redox state analyses by X-ray diffraction (XRD), X-ray fluorescence, and X-ray photoelectron spectroscopy (XPS), respectively. The distribution and leaching toxicity of heavy metals were assessed to evaluate potential effects on the environment. Compositional analyses revealed that Fe accounted for 35% of the magnetic fraction of pulverized ashes, which was approximately seven times that of the raw ash. In addition to Fe, elemental Ni, Mn, and Cr were also significantly enriched in the magnetic fractions. The mineralogical analysis determined that Fe was primarily present as hematite and magnetite, and metallic iron was also identified in the magnetic fraction samples. The XPS analysis further proved the existence of zero-valence Fe. However, a significant amount of Fe remained in the non-magnetic fractions, which could partially be ascribed to the intergrowth structure of the various minerals. The elevated concentrations of toxicity characteristic leaching procedure (TCLP)-extracted Mn, Ni, Cr, Cu, Pb, and Zn were primarily ascribed to the lower buffering capability of the magnetic fractions, with the enrichment of Mn, Ni, and Cr in the magnetic fractions also contributing to this elevation.

  3. DNA damage induced by coal dust, fly and bottom ash from coal combustion evaluated using the micronucleus test and comet assay in vitro.

    Science.gov (United States)

    Matzenbacher, Cristina Araujo; Garcia, Ana Letícia Hilario; Dos Santos, Marcela Silva; Nicolau, Caroline Cardoso; Premoli, Suziane; Corrêa, Dione Silva; de Souza, Claudia Telles; Niekraszewicz, Liana; Dias, Johnny Ferraz; Delgado, Tânia Valéria; Kalkreuth, Wolfgang; Grivicich, Ivana; da Silva, Juliana

    2017-02-15

    Coal mining and combustion generating huge amounts of bottom and fly ash are major causes of environmental pollution and health hazards due to the release of polycyclic aromatic hydrocarbons (PAH) and heavy metals. The Candiota coalfield in Rio Grande do Sul, is one of the largest open-cast coal mines in Brazil. The aim of this study was to evaluate genotoxic and mutagenic effects of coal, bottom ash and fly ash samples from Candiota with the comet assay (alkaline and modified version) and micronucleus test using the lung fibroblast cell line (V79). Qualitative and quantitative analysis of PAH and inorganic elements was carried out by High Performance Liquid Chromatography (HPLC) and by Particle-Induced X-ray Emission (PIXE) techniques respectively. The samples demonstrated genotoxic and mutagenic effects. The comet assay modified using DNA-glicosilase formamidopirimidina (FPG) endonuclease showed damage related to oxidative stress mechanisms. The amount of PAHs was higher in fly ash followed by pulverized coal. The amount of inorganic elements was highest in fly ash, followed by bottom ash. It is concluded that the samples induce DNA damage by mechanisms that include oxidative stress, due to their complex composition, and that protective measures have to be taken regarding occupational and environmental hazards.

  4. Pulverized-coal-firing small-size boiler for coal-cartridge system

    Energy Technology Data Exchange (ETDEWEB)

    1986-12-01

    Kawasaki Heavy Industries, Ltd. supplied a test boiler plant to the Iwakuni Experimental Station of the Coal Cartridge System (CCS) Promotion Association in September 1985; this was the first pulverized-coal-fired small industrial boiler in Japan. Tests will be performed for two years, until fiscal 1987, at the CCS Iwakuni Experimental Station to establish a method of coal-firing with a performance comparable to heavy oil firing. The boiler plant has been operating satisfactorily.

  5. Small scale experiment on the plasma assisted thermal chemical preparation and combustion of pulverized coal

    Energy Technology Data Exchange (ETDEWEB)

    Masaya, Sugimoto; Koichi, Takeda [Akita Prefectural University (Japan); Solonenko, O.P. [Institute of Theoretical and Applied Mechanics, Novosibirsk (Russian Federation); Sakashita, M.; Nakamura, M. [Japan Technical Information Service, Tokyo (Japan)

    2001-07-01

    Ignition and stable combustion of pulverized coal with Nitrogen and Air plasmas are investigated experimentally for some different types of coal. The experimental results show that air plasma has strong effect for ignition and stabilization of coal combustion. In addition, suppression of NO{sub x} production could be possible even in air plasma. It is possible to ignite and burn stably for the inferior coal that contains volatile matter in the ratio of only 10% of dry total mass. (authors)

  6. Analysis of Fracture Pattern of Pulverized Quartz Formed by Stick Slip Experiment

    Science.gov (United States)

    Nishikawa, Osamu; Muto, Jun; Otsuki, Kenshiro; Kano, Harumasa; Sasaki, Osamu

    2013-04-01

    In order to clarify how wall rocks of faults are damaged, fracture pattern analysis was performed imaging experimentally pulverized rocks by a micro-focus X-ray CT. Analyzed samples are core (diameter of 2cm) of single crystals of synthetic quartz and natural quartzites, which were pre-cut 50° to the core axis and mirror-polished. Experiments were conducted with axial strain rate of 10-3/s under the confining pressure of 180 MPa and room temperature using gas apparatus. Intense fracturing of the core occurred during the stick-slip with very large stress drop. Although thin melt layer is formed on the slip plane, the core is pulverized overall by tensile fracturing characterized by apparent lack of shear deformation. X-ray CT images demonstrate the fracture pattern being strongly controlled by slip direction and shear sense. Cracks are exponentially increased toward the slip plane and concentrated in the central portion rather than outer margin of core. Cracks tend to develop parallel to core axis and at high to moderate angles (90° ~ ±50°) with the plane including both core axis and slip direction, and lean to be higher angle to the surface near the slip plane. Due to this fracture pattern, the pulverized fragments show polygonal column or needle in shape with sharp and curving edges irrespective of their sizes, and the intensely fractured slip surface exhibit distinct rugged topography of an array of ridges developed perpendicular to slip direction. Mode and distribution pattern of fractures indicate that the stress concentration at the rupture front during dynamic rupture propagation or the constructive interference of reflected seismic waves focused at the center of core are possible mechanisms of pulverization.

  7. Bottom ash from fluidising bed boilers as filler material in district heating pipe culverts. Chemical and geotechnical characterisation; Pannsand som kringfyllnadsmaterial foer fjaerrvaermeroergravar. Kemisk och geoteknisk karaktaerisering av fluidbaeddsand

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Roger; Rogbeck, Jan; Suer, Pascal

    2004-01-01

    Bottom ashes from fluid bed boilers have been characterised, both geotechnically and chemically, in order to investigate the possibility to use them as filler material in district heating pipe culverts. Bottom ashes from both biofuel boilers and waste boilers are represented in this project. The companies which ashes have been characterised are Sundsvall Energi AB, Sydkraft OestVaerme AB, Sydkraft MaelarVaerme AB, Eskilstuna Miljoe och Energi, Stora Enso Fors, Soederenergi and Fortum Vaerme. A total of ten ashes have been analysed where three ashes originates from Sundsvall Energi AB, two from Sydkraft OestVaerme AB and one from the each of the remaining companies. The chemical analyses have been performed both on fresh ashes and on ashes aged for three months. The geotechnical analyses performed are grain size distribution, packing abilities and permeability. Chemical analyses performed are total content, available content, leaching tests (leaching both by shaking method and column procedure) and organic analyses (PAH, EOX, TOC, dioxin and fenol). The geotechnical analyses show that the ashes fulfils the demands that are put on the filler material used in district heating pipe culverts. When using the ashes in applications, light compaction should be performed due to the risk of crushing the material which may cause an increased amount of fine material. The leachability of fine material is larger than for coarse material. The ashes are relatively insensitive to precipitation. Bio fuel based bottom ashes have a lower content of environmental affecting substances than waste fuel based ashes. This is also shown in the leaching analyses. The leaching water from fresh ashes contains a higher concentration of leachable components than aged ashes. When aged the pH in the ashes decreases due to carbon uptake and hydration and this makes metals as Pb, Cu, Cr and Zn less mobile. On the other hand, an increase in leachability of Sb, Mo and SO{sub 4} is shown when the ashes

  8. Partial oxidation of methane to methanol over catalyst ZSM-5 from coal fly ash and rice husk ash

    Directory of Open Access Journals (Sweden)

    Mirda Yanti Fusia

    2017-01-01

    Full Text Available Methane is one of the greenhouse gases that can be converted into liquid fuels such as methanol to retain most of the energy of methane and produce a cleaner environment. The conversion of methane to methanol using ZMS-5 represents a breakthrough in the utilization of methane. However, material sources for zeolite synthesis as catalyst usually are pro-analysis grade materials, which are expensive. Therefore, in this research, coal fly ash and rice husk ash were used as raw materials for mesoporous ZSM-5 zeolite synthesis. First, coal fly ash and rice husk were subjected to pre-treatment to extract silicate (SiO44− and aluminate (AlO45− and impurities separation. The ZSM-5 zeolite was synthesized through hydrothermal treatment using two types of templates. After ZSM-5 was synthesized, it was modified with Cobalt through impregnation method. The catalytic activity of both ZSM-5 and Co/ZSM-5 zeolites as heterogeneous catalysts in partial oxidation of methane were preliminary tested and compared with that commercial one. The result showed that the zeolite catalyst ZSM-5 from fly ash coal and rice husk ash has the potential to be used as catalysts in the partial oxidation of methane to methanol.

  9. Co-sintering of treated APC-residues with bottom ash

    DEFF Research Database (Denmark)

    Bergfeldt, B.; Jensen, Dorthe Lærke; Vehlow, J.;

    2001-01-01

    the influence of co-sintering of Ferrox products with bottom ashes on the quality of the residues and the effects on the combustion process. Only few elements showed higher concentrations in the bottom ashes of these co-combustion tests compared to reference tests. No significant effect on the leaching...... behaviour of the bottom ashes could be found. During the co-combustion process an increase in SO2 concentrations in the raw gas and slightly lower temperatures in the fuel bed could be observed....

  10. Fundamental study of ash formation and deposition: Effect of reducing stoichiometry

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J.; Bool, L.E.; Kang, S.G. [and others

    1995-11-01

    This project is designed to examine the effects of combustion stoichiometry on the fundamental aspects of ash formation and ash deposit initiation. Emphasis is being placed on reducing stoichiometries associated with low-NOx combustion, although a range of oxidant/fuel ratios are being considered. Previous work has demonstrated that ash formation depends strongly upon coal mineralogy, including mineral type, size, amount, and the presence of organically associated inorganic species. Combustion temperature and the oxidation state of iron also play a significant role. As these latter items will vary with changes in stoichiometry, research to determine the net effect on deposition is required.

  11. DEVELOPMENT OF A NOVEL RADIATIVELY/CONDUCTIVELY STABILIZED BURNER FOR SIGNIFICANT REDUCTION OF NOx EMISSIONS AND FOR ADVANCING THE MODELING AND UNDERSTANDING OF PULVERIZED COAL COMBUSTION AND EMISSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Noam Lior; Stuart W. Churchill

    2003-10-01

    The primary objective of the proposed study was the study and analysis of, and design recommendations for, a novel radiatively-conductively stabilized combustion (RCSC) process for pulverized coal, which, based on our prior studies with both fluid fuels and pulverized coal, holds a high promise to reduce NO{sub x} production significantly. We have primarily engaged in continuing and improving our process modeling and analysis, obtained a large amount of quantitative information about the effects of the major parameters on NO{sub x} production, conducted an extensive exergy analysis of the process, evaluated the practicalities of employing the Radiatively-Conductively Stabilized Combustor (RCSC) to large power and heat plants, and improved the experimental facility. Prior experimental work has proven the feasibility of the combustor, but slagging during coal combustion was observed and should be dealt with. The primary outcomes and conclusions from the study are: (1) we developed a model and computer program that represents the pulverized coal combustion in the RCSC, (2) the model predicts that NO{sub x} emissions can be reduced by a number of methods, detailed in the report. (3) the exergy analysis points out at least a couple of possible ways to improve the exergetic efficiency in this combustor: increasing the effectiveness of thermal feedback, and adjusting the combustor mixture exit location, (4) because of the low coal flow rates necessitated in this study to obtain complete combustion in the burner, the size of a burner operating under the considered conditions would have to be up to an order of magnitude, larger than comparable commercial burners, but different flow configurations of the RCSC can yield higher feed rates and smaller dimensions, and should be investigated. Related to this contract, eleven papers were published in journals and conference proceedings, and ten invited presentations were given at university and research institutions, as well as at

  12. Insights into pulverized rock formation from dynamic rupture models of earthquakes

    Science.gov (United States)

    Payne, R. M.; Duan, B.

    2017-02-01

    Pulverized rocks (PR) are extremely incohesive and highly fractured rocks found within the damage zones of several large strike-slip faults around the world. They maintain their crystal structure, show little evidence of shearing or chemical alteration, and are believed to be produced by strong tensile forces. Several mechanisms for pulverization have been proposed based on simple qualitative analyses or laboratory experiments under simplified loading conditions. Numerical modelling, however, can offer new insights into what is needed to produce PR and likely conditions of formation. We perform dynamic rupture simulations of different earthquakes, varying the magnitude, the slip distribution, and the rupture speed (supershear and subshear), while measuring the stresses produced away from the fault. To contextualize our results, a basic threshold of 10 MPa is set as the tensile strength of the rock mass and recordings are made of where, when, and by how much this threshold is exceeded for each earthquake type. Guided by field observations, we discern that a large (>Mw 7.1) subshear earthquake along a bimaterial fault produces a pulverized rock distribution most consistent with observations. The damage is asymmetric with the majority on the stiffer side of the fault extending out for several hundred metres. Within this zone there is a large and sudden volumetric expansion in all directions as the rupture passes. We propose that such an extreme tensile stress state, repeated for every earthquake, eventually produces the PR seen in the field.

  13. Effect of microstructure on the breakage of tin bronze machining chips during pulverization via jet milling

    Science.gov (United States)

    Afshari, Elham; Ghambari, Mohammad; Farhangi, Hasan

    2016-11-01

    In this study, jet milling was used to recycle tin bronze machining chips into powder. The main purpose of this study was to assess the effect of the microstructure of tin bronze machining chips on their breakage behavior. An experimental target jet mill was used to pulverize machining chips of three different tin bronze alloys containing 7wt%, 10wt%, and 12wt% of tin. Optical and electron microscopy, as well as sieve analysis, were used to follow the trend of pulverization. Each alloy exhibited a distinct rate of size reduction, particle size distribution, and fracture surface appearance. The results showed that the degree of pulverization substantially increased with increasing tin content. This behavior was attributed to the higher number of machining cracks as well as the increased volume fraction of brittle δ phase in the alloys with higher tin contents. The δ phase was observed to strongly influence the creation of machining cracks as well as the nucleation and propagation of cracks during jet milling. In addition, a direct relationship was observed between the mean δ-phase spacing and the mean size of the jet-milled product; i.e., a decrease in the δ-phase spacing resulted in smaller particles.

  14. Scaling up nano-milling of poorly water soluble compounds using a rotation/revolution pulverizer.

    Science.gov (United States)

    Yuminoki, K; Tachibana, S; Nishimura, Y; Mori, H; Takatsuka, T; Hashimoto, N

    2016-02-01

    We previously reported that a rotation/revolution pulverizer (NP-100) could mill a small amount of a drug (0.1 g) into nanoparticles in several minutes. In this investigation, scale up from the milligram to the kilogram scale of the nano-milling process by the rotation/revolution pulverizer was studied. Phenytoin was used as a model drug with low solubility in water. After confirming the improvement of the phenytoin bioavailability by milling to nanoparticles using NP-100, scaling parameters were evaluated using NP-100 and the middle scale model of NP-100 (ARV-3000T). A theoretical equation for the specific collisional energy was adapted for wet milling; this suggested that the relative centrifugal acceleration of revolution (revolution G) and the drug concentration in the suspension were the two most important parameters. The results obtained using NP-100 and ARV-3000T correlated well when these two parameters were identical. These results were applied to the large scale model of NP-100 (ARV-10KT), where 2 kg (1 kg x 2) of phenytoin nanoparticles were obtained in 60 min. The results from PXRD and DSC indicated that the milled phenytoin by ARV-3000T and ARV-10KT maintained its crystallinity. These results suggest nano-milling using a rotation/revolution pulverizer will be widely applicable to the development of nano-medicine.

  15. Slagging characteristics of molten coal ash on silicon-aluminum combustion liners of boiler

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to study the slagging characteristics of boiler combustion liners during pulverized coal stream combustion,the slag samples on the surface of combustion liner were investigated by X-ray diffractometry,scan electron microscopy and energy dispersive X-ray analysis,and the transformation characteristics of the compositions and crystal phases were studied.The results show that the size of slag granules decreases as the slagging temperature increases;the crystallinity of coal ash I reduces to about 48.6% when the temperature is increased up to 1 350 ℃,and that of the coal ash Ⅱ reduces to about 65% when the temperature is increased up to 1 500 ℃;the encroachment of molten coal ash to the combustion liner is strengthened.At the same time,the diffusion and the segregation of the compositions in combustion liners have selectivity,which is in favor of enhancing the content of crystal phases,weakening the conglutination among molten slag compositions and combustion liner,and avoiding yielding big clinkers.But the diffusion of the compositions in combustion liners increases the porosity and decreases the mechanical intensity of combustion liner,and makes the slag encroachment to the liner become more serious.

  16. Ash in composting of source-separated catering waste.

    Science.gov (United States)

    Koivula, Niina; Räikkönen, Tarja; Urpilainen, Sari; Ranta, Jussi; Hänninen, Kari

    2004-07-01

    Our earlier experiments in small composters (220 l) indicated the favourable effect of ash from co-incineration of sorted dry waste on the composting of catering waste. The aim of this new study was to clarify further, at a scale of 10 m3, the feasibility of using similar ash as an additive in composting. Source-separated catering waste was mixed with bulking agent (peat and wood chips) and fuel ash from a small (4 MW) district heating power plant. Three compost mixes (CM) were obtained: CM I with 0%, CM II with 10% and CM III with 20 wt.% of fuel ash. These three different mixes were composted in a 10-m3 drum composter as three parallel experiments for 2 weeks each, from January to April 2000. After drum composting, masses were placed according to mixing proportions in separate curing piles. The catering waste fed to the drum was cold, sometimes icy. Even then the temperature rapidly increased to over 50 degrees C. In CM III, the temperature rose as high as 80 degrees C, and after the first week of composting the temperature was about 20 degrees C higher in the CMs II and III than in the CM I. It also improved the oxygen concentrations at the feeding end of the drum and obviously prevented the formation of H2S. No odour problems arose during the composting. Addition of ash increased the heavy metal contents of the composting masses, but the compost was suitable for cultivation or green area construction. Ash clearly decreased the loss of total nitrogen in a time span of 2 years. The lower amounts of nitrogen mean that the amounts applied per hectare can be greater than for normal composts. Measured by mineralization, the breaking down of the organic matter was more rapid in the CM III than in the CM I. Humic acid increased steadily during first 12 months composting, from the initial 39 mg/g organic matter to 115 and 137 mg/g in CMs II and III. Measured by temperature, mineralization and humification the addition of ash appeared to boost the composting. Ash had

  17. Preparation and characterization of carbon-enriched coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, B.; Izquierdo, M.T.; Mayoral, M.C.; Bona, M.T.; Martinez-Tarazona, R.M. [CSIC, Zaragoza (Spain)

    2008-09-15

    Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil-water. Yield in weight after sieving, unburned carbon content, and several physicochemical characteristics, of the obtained fractions were used to compare the performance of the beneficiation methods. Low carbon concentration was obtained by sieving. particularly in the case of Escucha FA. However, after acid demineralization or oil agglomeration, fractions containing unburned carbon in a range of 63% to 68% were obtained. These fractions showed differences in mineral phase composition and distribution depending on the FA and oil the beneficiation method used. The textural properties of the obtained fractions varied as a function of their carbon content and the beneficiation method used. However, no significant differences in morphology of the carbonaceous particles were found

  18. Experimental and theoretical analyses of pulverization and recycling of vulcanized rubber

    Science.gov (United States)

    Bilgili, Ecevit Atalay

    A two-stage process for recycling of vulcanized rubber was proposed. In the first stage, the vulcanized rubber was shredded into granulates, and then the granulates were pulverized into fine particles using a single screw extruder in the solid state shear extrusion (SSSE) process. In the second stage, the produced rubber powder was compression molded to produce new items. The major objective of this research is to understand the fundamental aspects of the pulverization and the compression molding of the rubber powder. Fine rubber particles were obtained using the SSSE process when the granulates were compressed sufficiently, and loss of strain energy due to viscoelastic stress relaxation was minimized by significant cooling in the pulverization zone. Agglomeration of rubber particles was found to be competing with the pulverization process. A sharp temperature gradient in the rubber was experimentally determined, which was qualitatively predicted by our heat transfer computer simulation. The rubber particles produced by the SSSE process and the unprocessed rubber granulates were analyzed using physical, thermal, and chemical characterization methods. The characterization study showed that the particles had irregular shapes with convoluted surfaces, and that the powder had a larger specific surface area compared with a cryogenically produced powder. The particles had lower crosslink density than the granulates indicating the breakage of sulfur crosslinks in the rubber, which makes the SSSE powder very suitable for many recycling applications. In the second stage, the produced powder within several size ranges was compression molded at various processing conditions. Rubber slabs with low-medium tensile strength were obtained without using any virgin rubber. It was found that the strength of the slabs is strongly dependent on the degree of particle bonding. Inhomogeneous shearing deformations of a homogeneous thermoelastic slab and a non-homogeneous rubber-like slab

  19. Reuse of partially sulphated CFBC ash as an SO{sub 2} sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Jia, L.; Anthony, E.J. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy; Nobili, M.; Telesca, A. [Basilicata Univ., Potenza (Italy). Dept. of Environmental Engineering and Physics; Montagnaro, F. [Naples Univ., Naples (Italy). Dept. of Chemistry

    2010-06-15

    Ash produced from circulating fluidized bed combustion (CFBC) boilers typically contains large amounts of unreacted calcium oxide (CaO) when limestone is added into the combustor for in situ removal of sulphur dioxide (SO{sub 2}). This paper reported on a study that evaluated the reactivation of partially sulphated ash obtained from an industrial circulating fluidized bed combustion (CFBC) boiler by hydration with liquid water and steam. A pilot-scale mini-CFBC was used to evaluate the results of reactivation on the bed ash by hydrating with liquid water and admixtures of sodium carbonate (Na{sub 2}CO{sub 3}) in solution or as powder. Re-sulphation tests on the hydrated samples were performed in a Cahn 1000 thermogravimetric analyzer (TGA) at 850 degrees C for 90 minutes in a simulated flue gas environment with sulphur dioxide (SO{sub 2}) concentration at 5000 ppm. Re-sulphation was carried out on unhydrated ash at the same conditions used in the baseline test. The TGA results showed that although liquid water and steam successfully hydrate and reactivate the unreacted CaO in the bed ash, the treated ashes sulphated to widely different extents. Attempts to reactivate fly ash with hydration failed, but the fly ash by itself was extremely reactive. When the treated ash was re-injected into the combustor with the fuel, the effect on SO{sub 2} removal efficiency was negligible if Na{sub 2}CO{sub 3} was added as powder. Doping with aqueous solution improved SO{sub 2} removal, but to a lesser extent than if only water hydration was used. Increasing the amount of water to reactivate the ash did not improve the sulphur capture capacity in the mini-CFBC. It was concluded that reactivation by water is the most practical way to reuse the partially sulphated bed ash as a sulphur sorbent. 21 refs., 7 tabs., 3 figs.

  20. Faecal-wood biomass co-combustion and ash composition analysis.

    Science.gov (United States)

    Somorin, Tosin Onabanjo; Kolios, Athanasios J; Parker, Alison; McAdam, Ewan; Williams, Leon; Tyrrel, Sean

    2017-09-01

    Fuel blending is a widely used approach in biomass combustion, particularly for feedstocks with low calorific value and high moisture content. In on-site sanitation technologies, fuel blending is proposed as a pre-treatment requirement to reduce moisture levels and improve the physiochemical properties of raw faeces prior to drying. This study investigates the co-combustion performance of wood dust: raw human faeces blends at varying air-to-fuel ratios in a bench-scale combustor test rig. It concludes with ash composition analyses and discusses their potential application and related problems. The study shows that a 50:50 wood dust (WD): raw human faeces (FC) can reduce moisture levels in raw human faeces by ∼40% prior to drying. The minimum acceptable blend for treating moist faeces without prior drying at a combustion air flow rate of 14-18 L/min is 30:70 WD: FC. For self-sustained ignition and flame propagation, the minimum combustion temperature required for conversion of the fuel to ash is ∼400 °C. The most abundant elements in faecal ash are potassium and calcium, while elements such as nickel, aluminium and iron are in trace quantities. This suggests the potential use of faecal ash as a soil conditioner, but increases the tendency for fly ash formation and sintering problems.

  1. Character of the Si and Al Phases in Coal Gangue and Its Ash

    Institute of Scientific and Technical Information of China (English)

    WANG Lihua; ZHAO Pengda; LI Geng

    2009-01-01

    Analysis of the Si and Al phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X-ray diffraction and Infrared Spectroscopy has been made in the present article to explore the diagram of the Si and Al phases in coal gangue fuel and its ashes. It is found that kaolinite and quartz are the main phases in coal gangue fuel. The ratio of moles Al_2O_3 to SiO_2 (i.e., Al_2O_(3(mole))/ SiO_(2(mole)) is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinit at about 984°C releases a large quantity of SiO_2, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio Al_2O_(3(mole))/SiO_(2(mole))and the components of coal gangue ash is analyzed, resulting in a formula to calculate the quantity of each phase. Applying the formula to the testing samples from an electric plant in north China supports the above conclusions.

  2. Ecological aspects of water coal fuel transportation and application

    Directory of Open Access Journals (Sweden)

    Anna SHVORNIKOVA

    2010-01-01

    Full Text Available This paper deals with the aspects of influence of transportation process and burning of water coal fuel on an ecological condition of environment. Also mathematical dependences between coal ash level and power consumption for transportation are presented.

  3. Hot-Gas Filter Ash Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, M.L.; Hurley, J.P.; Dockter, B.A.; O`Keefe, C.A.

    1997-07-01

    Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.

  4. 49 CFR 230.69 - Ash pans.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Ash pans. 230.69 Section 230.69 Transportation... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans § 230.69 Ash pans. Ash pans shall be securely supported from mud-rings or frames with no part less than...

  5. Assessment of pulverized-coal-fired combustion performance: Final report for the period September 1980--September 1983

    Energy Technology Data Exchange (ETDEWEB)

    Richter, W.F.; Clark, W.; Pohl, J.H.; Payne, R.

    1987-06-01

    The purpose of this program was to evaluate an engineering analysis procedure which could be used to assess the impact on thermal performance of converting gas and oil fired equipment to coal. The program consisted of four major tasks: (1) Engineering Analysis. The objective was to evaluate currently available models which could be used to predict combustor performance and to define a procedure which could be used to assess the impact of a coal firing in a boiler or furnace; (2) Reactor Studies. The purpose was to evaluate, under controlled conditions, the radiative properties of fly ash clouds; (3) Pilot Scale Experiments. This involved a combustion trial with gas and coals which were burned at 0.7 /times/ 10/sup 6/ Btu/hr in a pilot-scale combustor. The purpose was to verify and supplement the results of the small-scale reactor studies on the radiant properties of coal flames at larger scale; (4) Reporting. Engineering analysis procedures were used to identify those fuels related properties which had a major impact on the thermal performance of furnaces. The major result of the study is that thermal performance of coal-fired furnaces is dominated by the formation of fly ash deposits on the heat transfer surfaces. The key parameters which influence thermal performance are: thickness, thermal conductivity, and surface emissivity or absorptivity. 105 refs., 170 figs., 29 tabs.

  6. Utilization of ash products from combustion of shredded solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, P.F.; Mullen, J.F. (Energy Answers Corp, Albany, NY (US))

    1988-01-01

    One of the major problems with the siting, permitting, construction, and operation of a municipal solid waste-to- energy facility is the disposal of residues. As resource recovery increasingly becomes the disposal option of choice and necessity for municipalities across the country, the foci of environmental concerns has switched from groundwater contamination and inappropriate land use issues associated with landfilling, to air pollution control and residue disposal issues associated with waste combustion. It is suggested that the two separate ash streams can no longer reasonably be considered one and should be analyzed and treated separately, thereby increasing and enhancing the opportunity to recycle from the bottom ash (75 percent) and to focus on a reduced quantity of fly ash material (25 percent) for fixation and reuse or disposal. Such action would conform to the principles of, and the present regulatory trend towards waste minimization. However, there are many regulatory, institutional, and logistical barriers to such promising and seemingly simple waste reduction strategies. While the spirit of solid and hazardous waste legislation may emphasize waste minimization, ambiguities in the regulations have undermined the actual intent, creating an environment of confusion and indecisiveness with respect to treatment and disposal of ash from resource recovery facilities. This book reports on a research and development program to assess the feasibility and possible environmental impacts of utilizing a selected fraction of the bottom ash stream from processed refuse fuel-fired boilers as an aggregate substitute. The purpose of the research program is to develop data on the characteristics of bottom ash during exposure to rain and weathering in proposed applications.

  7. Energy properties of solid fossil fuels and solid biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Holubcik, Michal, E-mail: michal.holubcik@fstroj.uniza.sk; Jandacka, Jozef, E-mail: jozef.jandacka@fstroj.uniza.sk [University of Žilina, Faculty of Mechanical Engineering, Department of Power Engineering, Univerzitná 8215/1, 010 26 Žilina (Slovakia); Kolkova, Zuzana, E-mail: zuzana.kolkova@rc.uniza.sk [Research centre, University of Žilina, Univerzitna 8215/1, 010 26 Žilina (Slovakia)

    2016-06-30

    The paper deals about the problematic of energy properties of solid biofuels in comparison with solid fossil fuels. Biofuels are alternative to fossil fuels and their properties are very similar. During the experiments were done in detail experiments to obtain various properties of spruce wood pellets and wheat straw pellets like biofuels in comparison with brown coal and black coal like fossil fuels. There were tested moisture content, volatile content, fixed carbon content, ash content, elementary analysis (C, H, N, S content) and ash fusion temperatures. The results show that biofuels have some advantages and also disadvantages in comparison with solid fossil fuels.

  8. Energy properties of solid fossil fuels and solid biofuels

    Science.gov (United States)

    Holubcik, Michal; Kolkova, Zuzana; Jandacka, Jozef

    2016-06-01

    The paper deals about the problematic of energy properties of solid biofuels in comparison with solid fossil fuels. Biofuels are alternative to fossil fuels and their properties are very similar. During the experiments were done in detail experiments to obtain various properties of spruce wood pellets and wheat straw pellets like biofuels in comparison with brown coal and black coal like fossil fuels. There were tested moisture content, volatile content, fixed carbon content, ash content, elementary analysis (C, H, N, S content) and ash fusion temperatures. The results show that biofuels have some advantages and also disadvantages in comparison with solid fossil fuels.

  9. AshMeadowsNaucorid_CH

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify the areas where final critical habitat for the Ash Meadows Naucorid (Ambrysus amargosus) occur. "Nevada, Nye County. Point of Rocks Springs and...

  10. AshMeadowsNaucorid_CH

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify the areas where final critical habitat for the Ash Meadows Naucorid (Ambrysus amargosus) occur. "Nevada, Nye County. Point of Rocks Springs and...

  11. Nitrogen oxide abatement by distributed fuel addition

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.O.L.; Mereb, J.B.

    1991-09-20

    Reburning is examined as a means of NO{sub x} destruction in a 17 kW down-fired pulverized coal combustor. In reburning, a secondary fuel is introduced downstream of the primary flame to produce a reducing zone, favorable to NO destruction, and air is introduced further downstream to complete the combustion. Emphasis is on natural gas reburning and a bituminous coal primary flame. A parametric examination of reburning employing a statistical experimental design, is conducted, complemented by detailed experiments. Mechanisms governing the inter-conversion of nitrogenous species in the fuel rich reburn zone is explored. The effect of reburning on N{sub 2}O emissions, the effect of primary flame mode (premixed and diffusion) and the effect of distributing the reburning fuel, are also investigated.

  12. Thermal co-treatment of combustible hazardous waste and waste incineration fly ash in a rotary kiln.

    Science.gov (United States)

    Huber, Florian; Blasenbauer, Dominik; Mallow, Ole; Lederer, Jakob; Winter, Franz; Fellner, Johann

    2016-12-01

    As current disposal practices for municipal solid waste incineration (MSWI) fly ash are either associated with significant costs or negative environmental impacts, an alternative treatment was investigated in a field scale experiment. Thereto, two rotary kilns were fed with hazardous waste, and moistened MSWI fly ash (water content of 23%) was added to the fuel of one kiln with a ratio of 169kg/Mg hazardous waste for 54h and 300kg/Mg hazardous waste for 48h while the other kiln was used as a reference. It was shown that the vast majority (>90%) of the inserted MSWI fly ash was transferred to the bottom ash of the rotary kiln. This bottom ash complied with the legal limits for non-hazardous waste landfills, thereby demonstrating the potential of the investigated method to transfer hazardous waste (MSWI fly ash) into non-hazardous waste (bottom ash). The results of a simple mixing test (MSWI fly ash and rotary kiln bottom ash have been mixed accordingly without thermal treatment) revealed that the observed transformation of hazardous MSWI fly ash into non-hazardous bottom ash during thermal co-treatment cannot be referred to dilution, as the mixture did not comply with legal limits for non-hazardous waste landfills. For the newly generated fly ash of the kiln, an increase in the concentration of Cd, K and Pb by 54%, 57% and 22%, respectively, was observed. In general, the operation of the rotary kiln was not impaired by the MSWI fly ash addition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Synthesis of cracked Calophyllum inophyllum oil using fly ash catalyst for diesel engine application

    KAUST Repository

    Muthukumaran, N.

    2015-04-16

    In this study, production of hydrocarbon fuel from Calophyllum inophyllum oil has been characterized for diesel engine application, by appraising essential fuel processing parameters. As opposed to traditional trans-esterification process, the reported oil was cracked using a catalyst, as the latter improves the fuel properties better than the former. In a bid to make the production process economically viable, a waste and cheap catalyst, RFA (raw fly ash), has been capitalized for the cracking process as against the conventional zeolite catalyst. The fuel production process, which is performed in a fixed bed catalytic reactor, was done methodologically after comprehensively studying the characteristics of fly ash catalyst. Significantly, fly ash characterization was realized using SEM and EDS, which demarcated the surface and internal structures of fly ash particles before and after cracking. After the production of hydrocarbon fuel from C. inophyllum oil, the performed compositional analysis in GC-MS revealed the presence of esters, parfins and olefins. Followed by the characterization of catalytically cracked C. inophyllum oil, suitable blends of it with diesel were tested in a single cylinder diesel engine. From the engine experimental results, BTE (brake thermal efficiency) of the engine for B25 (25% cracked C. inophyllum oil and 75% diesel) was observed to be closer to diesel, while it decreased for higher blends. On the other hand, emissions such as HC (hydrocarbon), CO (carbon monoxide) and smoke were found to be comparable for B25 with diesel. © 2015 Elsevier Ltd. All rights reserved.

  14. pulver: an R package for parallel ultra-rapid p-value computation for linear regression interaction terms.

    Science.gov (United States)

    Molnos, Sophie; Baumbach, Clemens; Wahl, Simone; Müller-Nurasyid, Martina; Strauch, Konstantin; Wang-Sattler, Rui; Waldenberger, Melanie; Meitinger, Thomas; Adamski, Jerzy; Kastenmüller, Gabi; Suhre, Karsten; Peters, Annette; Grallert, Harald; Theis, Fabian J; Gieger, Christian

    2017-09-29

    Genome-wide association studies allow us to understand the genetics of complex diseases. Human metabolism provides information about the disease-causing mechanisms, so it is usual to investigate the associations between genetic variants and metabolite levels. However, only considering genetic variants and their effects on one trait ignores the possible interplay between different "omics" layers. Existing tools only consider single-nucleotide polymorphism (SNP)-SNP interactions, and no practical tool is available for large-scale investigations of the interactions between pairs of arbitrary quantitative variables. We developed an R package called pulver to compute p-values for the interaction term in a very large number of linear regression models. Comparisons based on simulated data showed that pulver is much faster than the existing tools. This is achieved by using the correlation coefficient to test the null-hypothesis, which avoids the costly computation of inversions. Additional tricks are a rearrangement of the order, when iterating through the different "omics" layers, and implementing this algorithm in the fast programming language C++. Furthermore, we applied our algorithm to data from the German KORA study to investigate a real-world problem involving the interplay among DNA methylation, genetic variants, and metabolite levels. The pulver package is a convenient and rapid tool for screening huge numbers of linear regression models for significant interaction terms in arbitrary pairs of quantitative variables. pulver is written in R and C++, and can be downloaded freely from CRAN at https://cran.r-project.org/web/packages/pulver/ .

  15. Fly ash. Quality recycling material

    Energy Technology Data Exchange (ETDEWEB)

    Blomster, D.; Leisio, C.

    1996-11-01

    Imatran Voima`s coal-fired power plants not only generate power and heat but also produce fly ash which is suitable raw material for recycling. This material for recycling is produced in the flue gas cleaning process. It is economical and, thanks to close quality control, is suitable for use as a raw material in the building materials industry, in asphalt production, and in earthworks. Structures made from fly ash are also safe from an environmental point of view. (orig.)

  16. Fly ash. Quality recycling material

    Energy Technology Data Exchange (ETDEWEB)

    Blomster, D.; Leisio, C.

    1996-11-01

    Imatran Voima`s coal-fired power plants not only generate power and heat but also produce fly ash which is suitable raw material for recycling. This material for recycling is produced in the flue gas cleaning process. It is economical and, thanks to close quality control, is suitable for use as a raw material in the building materials industry, in asphalt production, and in earthworks. Structures made from fly ash are also safe from an environmental point of view. (orig.)

  17. Iron making technology with fuels and other materials injection in blast furnace tuyeres. Part 1. Auxiliary fuels characteristics and its influence in the blast furnace process; Tecnologia de fabricacion de arrabio con la inyeccion de combustibles y otros materiales por toberas en el horno alto. I parte. Caracteristicas de los combustibles auxiliares y su influencia en el proceso del horno alto

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, L. [Union de Empresas de Recuperacion de Materias Primas. Ciudad de La Habana (Cuba); Cores, A.; Formoso, A. [Centro Nacional de Investigaciones Metalurgicas. Madrid (Spain); Babich, A.; Yaroshevskii, S. [Universidad Estatal Tecnologica de Donetsk. Ucrania (Ukraine)

    1998-06-01

    The injection of fuels by tuyeres in the blast furnace is a used practice in most furnaces with the principal aim to reduce the coke consumption by ton of pig iron produced. The nature of these fuels is very diverse and depends on the resources of each country and of the fuel price. At this moment the coal injection (pulverized and granular) is the most extended practice, and the number of furnaces with facilities for coal injection increases continuously. (Author) 14 refs.

  18. Ash characteristics and plant nutrients in some aquatic biomasses

    Science.gov (United States)

    Masto, Reginald; Pandit, Ankita; George, Joshy; Mukhopadhyay, Sangeeta; Selvi, Vetrivel; Ram, Lal

    2016-04-01

    Aquatic biomasses are explored as potential fuel source for direct combustion because of their faster growth and no land requirement. The energy density and the ash characteristics of the aquatic biomasses are to be evaluated for their suitability for energy extraction. In the study, four aquatic plant samples namely Eichornia crassipes, Hydrilla verticilleta, Lemna minor, Spirogyra spp were collected from a pond in Digwadih Campus of Central Institute of Mining and Fuel Research, Dhanbad. The biomasses were air dried, powdered and ashed at different temperatures. Volatile C was relatively lower in Spirogyra and Hydrilla (53 %) than Eichornia (62.6 %) or Lemna (59.7 %), whereas fixed C was higher for Eichornia and Lemna (about 10 %) and lower for Hydrilla (1 %). Ultimate analysis showed that the carbon content was in the order Eichornia > Lemna > Spirogyra > Hydrilla. The IR spectra of each raw biomass is compared to their respective ashes obtained at different temperatures (500-900°C). With increase in ashing temperature from 500-900°C there is gradual breakdown of the cellulosic structure hence, peaks around 2900-2800cm-1 caused by aliphatic C-H vibration tends to disappear slowly in ash. More number of peaks appears at lower wavenumbers in ashes of all the biomass samples indicating towards increased percentage of inorganic ion species. Considerable enrichment of SiO2 is validated with prominent peaks at 1100-900 cm-1 in all the ashes. Lemna and Spirogyra has a similar ash composition (Si > Al > Ca > K), whereas, Ca was higher in Hydrilla (Si > Ca > K > Al). Eichornia (Si > K > Ca > Al) has higher K and Ca than Al. SiO2 and Al2O3 were higher in Spirogyra, while SiO2 and CaO in Eichornia and Hydrilla. K first increased from 500-700/800⁰C, and then decreased from 800-900⁰C. Cl is lost slowly in ash from 500-700/800⁰C and then by a drastic reduction from 800-900⁰C. S is enhanced in ash at all temperatures although the change is quite small. Most of the Cl

  19. Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments.

    Science.gov (United States)

    Mõtlep, Riho; Sild, Terje; Puura, Erik; Kirsimäe, Kalle

    2010-12-15

    Oil shale is a primary fuel in the Estonian energy sector. After combustion 45-48% of the oil shale is left over as ash, producing about 5-7 Mt of ash, which is deposited on ash plateaus annually almost without any reuse. This study focuses on oil shale ash plateau sediment mineralogy, its hydration and diagenetic transformations, a study that has not been addressed. Oil shale ash wastes are considered as the biggest pollution sources in Estonia and thus determining the composition and properties of oil shale ash sediment are important to assess its environmental implications and also its possible reusability. A study of fresh ash and drillcore samples from ash plateau sediment was conducted by X-ray diffractometry and scanning electron microscopy. The oil shale is highly calcareous, and the ash that remains after combustion is derived from the decomposition of carbonate minerals. It is rich in lime and anhydrite that are unstable phases under hydrous conditions. These processes and the diagenetic alteration of other phases determine the composition of the plateau sediment. Dominant phases in the ash are hydration and associated transformation products: calcite, ettringite, portlandite and hydrocalumite. The prevailing mineral phases (portlandite, ettringite) cause highly alkaline leachates, pH 12-13. Neutralization of these leachates under natural conditions, by rainwater leaching/neutralization and slow transformation (e.g. carbonation) of the aforementioned unstable phases into more stable forms, takes, at best, hundreds or even hundreds of thousands of years. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. The immersion freezing behavior of ash particles from wood and brown coal burning

    Science.gov (United States)

    Grawe, Sarah; Augustin-Bauditz, Stefanie; Hartmann, Susan; Hellner, Lisa; Pettersson, Jan B. C.; Prager, Andrea; Stratmann, Frank; Wex, Heike

    2016-11-01

    It is generally known that ash particles from coal combustion can trigger ice nucleation when they interact with water vapor and/or supercooled droplets. However, data on the ice nucleation of ash particles from different sources, including both anthropogenic and natural combustion processes, are still scarce. As fossil energy sources still fuel the largest proportion of electric power production worldwide, and biomass burning contributes significantly to the global aerosol loading, further data are needed to better assess the ice nucleating efficiency of ash particles. In the framework of this study, we found that ash particles from brown coal (i.e., lignite) burning are up to 2 orders of magnitude more ice active in the immersion mode below -32 °C than those from wood burning. Fly ash from a coal-fired power plant was shown to be the most efficient at nucleating ice. Furthermore, the influence of various particle generation methods on the freezing behavior was studied. For instance, particles were generated either by dispersion of dry sample material, or by atomization of ash-water suspensions, and then led into the Leipzig Aerosol Cloud Interaction Simulator (LACIS) where the immersion freezing behavior was examined. Whereas the immersion freezing behavior of ashes from wood burning was not affected by the particle generation method, it depended on the type of particle generation for ash from brown coal. It was also found that the common practice of treating prepared suspensions in an ultrasonic bath to avoid aggregation of particles led to an enhanced ice nucleation activity. The findings of this study suggest (a) that ash from brown coal burning may influence immersion freezing in clouds close to the source and (b) that the freezing behavior of ash particles may be altered by a change in sample preparation and/or particle generation.

  1. Anatomy of an upgraded pulverized coal facility: Combustion modification through flue gas scrubbing

    Energy Technology Data Exchange (ETDEWEB)

    Watts, J.U. [Dept. of Energy, Pittsburgh, PA (United States). Federal Energy Technology Center; Savichky, W.J.; O`Dea, D.T. [New York State Electric and Gas Corp., Binghamton, NY (United States)

    1997-12-31

    Regeneration is a biological term for formation or creating anew. In the case of Milliken station, a species of steam generation (Tangentus coali) regeneration refers to refitting critical systems with the latest technological advances to reduce emissions while maintaining or improving performance. The plant has undergone a series of operations which provided anatomical changes as well as a face lift. Each of the two units were place in suspended animation (outage) to allow these changes to be made. The paper describes the project which includes retrofitting combustion systems, pulverizers, boiler liners, scrubbers, and control room. This retrofit is meant to increase thermal efficiency while reducing the formation of nitrogen oxides.

  2. ITER helium ash accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. (Oak Ridge National Lab., TN (USA)); Dippel, K.H.; Finken, K.H. (Forschungszentrum Juelich GmbH (Germany, F.R.). Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  3. Soot, organics, and ultrafine ash from air- and oxy-fired coal combustion

    KAUST Repository

    Andersen, Myrrha E.

    2016-10-19

    Pulverized bituminous coal was burned in a 10. W externally heated entrained flow furnace under air-combustion and three oxy-combustion inlet oxygen conditions (28, 32, and 36%). Experiments were designed to produce flames with practically relevant stoichiometric ratios (SR. =1.2-1.4) and constant residence times (2.3. s). Size-classified fly ash samples were collected, and measurements focused on the soot, elemental carbon (EC), and organic carbon (OC) composition of the total and ultrafine (<0.6. μm) fly ash. Results indicate that although the total fly ash carbon, as measured by loss on ignition, was always acceptably low (<2%) with all three oxy-combustion conditions lower than air-combustion, the ultrafine fly ash for both air-fired and oxy-fired combustion conditions consists primarily of carbonaceous material (50-95%). Carbonaceous components on particles <0.6. μm measured by a thermal optical method showed that large fractions (52-93%) consisted of OC rather than EC, as expected. This observation was supported by thermogravimetric analysis indicating that for the air, 28% oxy, and 32% oxy conditions, 14-71% of this material may be OC volatilizing between 100. C and 550. C with the remaining 29-86% being EC/soot. However, for the 36% oxy condition, OC may comprise over 90% of the ultrafine carbon with a much smaller EC/soot contribution. These data were interpreted by considering the effects of oxy-combustion on flame attachment, ignition delay, and soot oxidation of a bituminous coal, and the effects of these processes on OC and EC emissions. Flame aerodynamics and inlet oxidant composition may influence emissions of organic hazardous air pollutants (HAPs) from a bituminous coal. During oxy-coal combustion, judicious control of inlet oxygen concentration and placement may be used to minimize organic HAP and soot emissions.

  4. Volcanic ash infrared signature: realistic ash particle shapes compared to spherical ash particles

    OpenAIRE

    A. Kylling; Kahnert, M.; Lindqvist, H.; T. Nousiainen

    2013-01-01

    The reverse absorption technique is often used to detect volcanic clouds from thermal infrared satellite measurements. From these measurements particle size and mass loading may also be estimated using radiative transfer modelling. The radiative transfer modelling usually assumes that the ash particles are spherical. We calculate thermal infrared optical properties of highly irregular and porous ash particles and compare these with mass- and volume-equivalent spherical models. Furtherm...

  5. A novel model for cost performance evaluation of pulverized coal injected into blast furnace based on effective calorific value

    Institute of Scientific and Technical Information of China (English)

    徐润生; 张建良; 左海滨; 李克江; 宋腾飞; 邵久刚

    2015-01-01

    The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.

  6. Uptake of {sup 137}Cs by berries, mushrooms and needles of Scots pine in peatland forests after wood ash application

    Energy Technology Data Exchange (ETDEWEB)

    Vetikko, Virve, E-mail: virve.vetikko@stuk.f [STUK, Radiation and Nuclear Safety Authority, Research and Environmental Surveillance, P.O.Box 14, FI-00881 Helsinki (Finland); Rantavaara, Aino, E-mail: aino.rantavaara@stuk.f [STUK, Radiation and Nuclear Safety Authority, Research and Environmental Surveillance, P.O.Box 14, FI-00881 Helsinki (Finland); Moilanen, Mikko, E-mail: mikko.moilanen@metla.f [Finnish Forest Research Institute (METLA), Muhos Research Unit, Kirkkosaarentie 7, FI-91500 Muhos (Finland)

    2010-12-15

    Increasing use of wood fuels for energy production in Finland since the 1990s implies that large quantities of the generated ashes will be available for forest fertilization. The aim of this study was to analyse the effect of wood ash application on {sup 137}Cs activity concentrations in Scots pine (Pinus sylvestris L.) needles and certain berries and mushrooms on drained peatlands. The study was based on field experiments carried out on two mires in Finland in 1997-1998. Two different types of wood ash were applied at dosages of 3500, 3700, 10 500 and 11 100 kg ha{sup -1}. Wood ash did not increase {sup 137}Cs activity concentration in plants in the second growing season following application. On the contrary, a decrease in {sup 137}Cs activity concentration was seen in the plants of the ecosystem on drained peatlands. This result is of importance, for instance, when recycling of ash is being planned. -- Research highlights: {yields} The study confirmed the fast response of Scots pine to ash application. {yields} Wood ash decreased the 137Cs activity concentration in Scots pine needles. {yields} Wood ash did not increase the 137Cs contamination in wild berries and mushrooms. {yields} The results are of importance when recycling of ash is being planned.

  7. Electrodialytic remediation of fly ash from co-combustion of wood and straw

    DEFF Research Database (Denmark)

    Chen, Wan; Jensen, Pernille Erland; Ottosen, Lisbeth M.

    2015-01-01

    The heavy metal content in fly ash from biomass combustion, such as straw, wood and sludge, often needs reducing before the ash can be used as fertilizer for agricultural land or as a component in the production of construction materials. In this study, fly ash from a boiler fueled with wood chips...... and straw was treated either by electrodialytic remediation (EDR) directly or by a combination of EDR and pre-wash with distilled water to investigate the possibilities of reducing the heavy metal content and reusing nutrients as fertilizer and bulk material in construction materials. Different experimental...... set-ups were tested for EDR treatment primarily of Cd and Pb as well as of Cu and Zn. Elemental contents such as K, P and Ni were compared in ash samples before and after treatment. The results showed that pre-washing caused an increase in total concentrations of most heavy metals because the highly...

  8. Effect of circulating ash from CFB boilers on NO and N20 emission

    Institute of Scientific and Technical Information of China (English)

    Xiangsong HOU; Shi YANG; Junfu LU; Hai ZHANG; Guangxi YUE

    2009-01-01

    NO and N2O emissions from circulating fluidized bed (CFB) boilers are determined by their formation and destruction rates in the furnace. The effect of circulating ash from a CFB boiler on NO and N2O emissions were investigated in a laboratory-scale fluidized bed reactor. The results show that the residue char in circulating ash and the CO generated from the char play an important role in NO reduction and N2O formation; however, active components of circulating ash such as CaO, Fe2O3 accelerate the decomposition of N2O. Experiment was also conducted on a 75 t/h CFB boiler fueled with the mixture of anthracite and biomass. The lower residue carbon content of circulating ash in this experiment is lower; therefore, the reacting rate of NO deoxidize is limited. This result verified the conclusion of laboratory research.

  9. Fuel Handbook[Wood and other renewable fuels

    Energy Technology Data Exchange (ETDEWEB)

    Stroemberg, Birgitta [TPS Termiska Processer AB, Nykoeping (SE)] (ed.)

    2006-03-15

    This handbook on renewable fuels is intended for power and heat producers in Sweden. This fuel handbook provides, from a plant owner's perspective, a method to evaluate different fuels on the market. The fuel handbook concerns renewable fuels (but does not include household waste) that are available on the Swedish market today or fuels that have potential to be available within the next ten years. The handbook covers 26 different fuels. Analysis data, special properties, operating experiences and literature references are outlined for each fuel. [Special properties, operating experiences and literature references are not included in this English version] The handbook also contains: A proposed methodology for introduction of new fuels. A recommendation of analyses and tests to perform in order to reduce the risk of problems is presented. [The recommendation of analyses and tests is not included in the English version] A summary of relevant laws and taxes for energy production, with references to relevant documentation. [Only laws and taxes regarding EU are included] Theory and background to evaluate a fuel with respect to combustion, ash and corrosion properties and methods that can be used for such evaluations. Summary of standards, databases and handbooks on biomass fuels and other solid fuels, and links to web sites where further information about the fuels can be found. The appendices includes: A methodology for trial firing of fuels. Calculations procedures for, amongst others, heating value, flue gas composition, key number and free fall velocity [Free fall velocity is not included in the English version]. In addition, conversion routines between different units for a number of different applications are provided. Fuel analyses are presented in the appendix. (The report is a translation of parts of the report VARMEFORSK--911 published in 2005)

  10. Controlling formaldehyde emissions with boiler ash.

    Science.gov (United States)

    Cowan, Jennifer; Abu-Daabes, Malyuba; Banerjee, Sujit

    2005-07-01

    Fluidized wood ash reduces formaldehyde in air from about 20 to formaldehyde reduction increases with increasing moisture content of the ash. Sorption of formaldehyde to ash can be substantially accounted for by partitioning to the water contained in the ash followed by rate-controlling binding to the ash solids. Adsorption occurs at temperatures of up to 165 degrees C; oxidation predominates thereafter. It is proposed that formaldehyde could be stripped from an air stream in a fluidized bed containing ash, which could then be returned to a boiler to incinerate the formaldehyde.

  11. 小型常压煤粉仓惰性气体保护系统设计及应用%Design and Application of Inert Gas Protection System to Small-Scale Atmospheric Pressure Pulverized Coal Bunker

    Institute of Scientific and Technical Information of China (English)

    徐尧; 王乃继; 肖翠微

    2012-01-01

    According to the fuel safety storage requirements of the pulverized coal-fired industrial boiler, in order to solve the coal spon- taneous combustion problems caused by CO content and the temperature increased in the coal bunker, with the related national standards and overseas design handbook, the design calculation method and system control plan of the inert gas protection system was provided for the small-scale atmospheric pressure pulverized coal bunker. According to the two coal bunkers with volume of 40 m^3 , an inert gas pro- tection system of the small-scale atmospheric pressure pulverized coal bunker was designed. When the CO content in the pulverized coal bunker reached at 1 200×10^-6 or the temperature at the any location of the bunker was over 70 ℃, the inert gas protection system would have a protection to the coal bunker with the automatic start, manual start or mechanical emergency start. The project cases were applied to verify the inert gas protection system. The result showed that when the storage value of the protective gas CO2 would be 355 kg, the low pressure CO2 inerting system applied to the protection of the pulverized coal bunker could remarkably reduce the risks of the pulverized coal spontaneous combustion.%为解决煤粉仓CO浓度或温度增高导致的自燃问题,根据煤粉工业锅炉系统燃料安全储存需求,参照相关国家标准和国外设计手册,提出了小型常压煤粉仓惰性气体保护系统设计计算方法和系统控制方案。针对2台容积40m^3的煤粉仓设计了小型常压煤粉仓惰性气体保护系统,当检测到煤粉仓内CO体积分数达1200×10^-6或任意一处温度高于70℃时,系统可通过自动启动、手动启动、机械应急启动3种方式对煤粉仓保护,结合工程实例对该系统予以验证。结果表明:采用低压CO2惰化系统对煤粉仓实施保护,当保护气体CO2的储存量为355kg,可明显降低煤粉自燃的风险。

  12. Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

    Science.gov (United States)

    Brook, Anna; Hamzi, Seham; Wittenberg, Lea

    2015-04-01

    produced ash has significant and not always constructive pedological, ecological, hydrological and geomorphological effects and impacts (Shakesby, 2011). Abundant scientific information is assembled either from control fires by collecting samples before and after wildfire event, or conducting laboratory experiments exanimating data under truly isolated conditions (Lugassi et al., 2013). However, an integration and synthesis of the knowledge about ash including deeper understanding of inter-correlation between chemical, physical and morphological compounds in open post-burn environment and its possible interactions in soil formation or impact on soil composition are highly needed. The main aim of the presented study was to advance the science of soil-fire relationship by recognizing the remains ash as a new soil-forming factor, on par with the traditionally recognized factors: parent material, topography, time, climate, organisms, and recently recognized human activity as the sixth factor. This research was conducted to develop new methods to assess impacts and quantify the contributions/influences of post-fire products, mainly ash, on soil composition and soil properties in post-burned environment. We conducted several controlled experiments using 40 soil samples (typical Mediterranean Rendzina soil, pH 6.84, a grayish-brown, humus- and free calcium carbonate- rich, intra-zonal). The samples include bare soils and different types and loads of forest litter, were exposed to different temperatures (200° C, 400° C and 600° C) in a muffle furnace for 2 hours (Pereira et al. 2011) as fire temperature plays a key role in determining ash properties. The ash produced at a low temperatures (50% carbon and retains many of the structural characteristics of the parent material. At higher temperatures, the residue ash is greyish, consisted of very fine particles that preserve almost none of the original structural characteristics of the fuel (Woods and Balfour, 2008) creating

  13. Engineering and organizational solutions for improvement of engineering and economic characteristics of the TPE-216 boilers equipped with MV-3300/800/490 pulverizing fans

    Science.gov (United States)

    Kirillov, M. V.; Safronov, P. G.

    2014-07-01

    Efficiency of coal-fired boilers is determined in many respects by optimal operation of the coal-pulverizing plants that are increasingly frequently equipped with pulverizing fans. By an example of retrofitted MV-3300/800/490 pulverizing fans, the effects of different factors on the performance and economic efficiency of the coal-pulverizing plants are analyzed. The experience gained in retrofitting MV-3300/800/490 pulverizing fans by introducing the three-crusher operation mode of a TPE-216 boiler employing the internal recirculation and a blading device in the classifier was also studied. Optimization of the boiler's operation mode was made when switching over from the four-crusher to the three-crusher mode, which considerably improved the engineering and economic characteristics.

  14. Lignite Fuel Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Charles Bullinger; Nenad Sarunac

    2010-03-31

    Pulverized coal power plants which fire lignites and other low-rank high-moisture coals generally operate with reduced efficiencies and increased stack emissions due to the impacts of high fuel moisture on stack heat loss and pulverizer and fan power. A process that uses plant waste heat sources to evaporate a portion of the fuel moisture from the lignite feedstock in a moving bed fluidized bed dryer (FBD) was developed in the U.S. by a team led by Great River Energy (GRE). The demonstration was conducted with Department of Energy (DOE) funding under DOE Award Number DE-FC26-04NT41763. The objectives of GRE's Lignite Fuel Enhancement project were to demonstrate reduction in lignite moisture content by using heat rejected from the power plant, apply technology at full scale at Coal Creek Station (CCS), and commercialize it. The Coal Creek Project has involved several stages, beginning with lignite drying tests in a laboratory-scale FBD at the Energy Research Center (ERC) and development of theoretical models for predicting dryer performance. Using results from these early stage research efforts, GRE built a 2 ton/hour pilot-scale dryer, and a 75 ton/hour prototype drying system at Coal Creek Station. Operated over a range of drying conditions, the results from the pilot-scale and prototype-scale dryers confirmed the performance of the basic dryer design concept and provided the knowledge base needed to scale the process up to commercial size. Phase 2 of the GRE's Lignite Fuel Enhancement project included design, construction and integration of a full-scale commercial coal drying system (four FBDs per unit) with Coal Creek Units 1 and 2 heat sources and coal handling system. Two series of controlled tests were conducted at Coal Creek Unit 1 with wet and dried lignite to determine effect of dried lignite on unit performance and emissions. Wet lignite was fired during the first, wet baseline, test series conducted in September 2009. The second test series was

  15. Ash chemistry and sintering, verification of the mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Skrifvars, B.J.; Backman, R.; Lauren, T.; Uusikartano, T.; Malm, H.; Stenstroem, P.; Vesterkvist, M. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    In this project four sintering mechanisms have been studied, i.e., partial melting with a viscous liquid, partial melting with a non-viscous liquid, chemical reaction sintering and solid state sintering. The work has aimed at improving the understanding of ash sintering mechanisms and quantifying their role in combustion and gasification. The work has been oriented in particular on the understanding of biomass ash behavior. The work has not directly focused on any specific technical application. However, results can also be applied on other fuels such as brown coal, petroleum coke, black liquor and different types of wastes (PDF, RDF, MSW). During 1996 the work has focused on identifying bed agglomeration mechanisms and analysing bed agglomerates in both full scale and lab scale FB reactors, as well as comparing how well the compression strength based sintering test can predict bed agglomeration in an FB furnace. (orig.)

  16. Investigation on Pulverized Coal Combustion Behavior by Non-Isothermic Integral Thermogravimetry Method

    Institute of Scientific and Technical Information of China (English)

    QI Cheng-lin; ZHANG Jian-liang; LIN Xiang-hai; LIU Qin-yuan; WANG Xiao-liu

    2011-01-01

    The combustion process of pulverized coal was investigated by non-isothermic integral thermogravimetry. The thermogravimetry curves were fitted by the Coats-Redferm approximation function, and kinetic parameters and characteristic temperatures were obtained. The optimal mixing ratio and particle size can be ascertained. The characteristic temperature of pulverized coal can be obtained from the thermogravimetry curve, and the combustion of coal can be divided into homogeneous and heterogeneous combustion according to the differential thermal analysis curve. The activation energy of a single type of coal ranking from low to high is as follows: bituminous coal, meager-lean coal, and anthracite. In the first mixing method, with more low-price meager-lean coal B replacing high price anthracite A, the activation energy slightly decreases; with more bituminous coal replacing meager-lean coal, total tendency makes a declining of activation. In the later mixing method, with an increase in particle size, a declining activation energy can be seen in total tendency.

  17. SYSTEM OF PRECISE DOSING OF COAGULANT IN THE PULVERIZING AERATOR POWERED BY WIND USING FUZZY LOGIC

    Directory of Open Access Journals (Sweden)

    Andrzej Osuch

    2017-06-01

    Full Text Available One of the methods used to support land restoration lakes is the method of pulverizing aeration. Use of aerators powered exclusively by wind improves the condition of reservoirs, while not compromising the environment. The pulverizing aeration process drive is windy on the water aeration zone near bottom, while removing harmful gases anaerobic metabolism. Aerators of this type due to the unique method of operation also enable dosing of inactivation coagulants with oxygenated water to the depths of the lake. Mileage coagulant dosing can be made dependent on the speed of the wind, which has an impact on the performance of his work, because with the increase of wind speed dispensing valve coagulants should be stronger open. One of the methods for assessing the state of lakes is to measure water transparency. The softer visibility, the most likely state of the water is better. Dosage of coagulant so you can make the transparency of the water. Similarly, with increasing transparency water dispensing valve should be more covered up. Control of the drain valve dispenser coagulant can be simultaneously dependent on two factors. The study was designed method of control drain valve dispenser coagulant using fuzzy inference.

  18. Ash in fire affected ecosystems

    Science.gov (United States)

    Pereira, Paulo; Jordan, Antonio; Cerda, Artemi; Martin, Deborah

    2015-04-01

    Ash in fire affected ecosystems Ash lefts an important footprint in the ecosystems and has a key role in the immediate period after the fire (Bodi et al., 2014; Pereira et al., 2015). It is an important source of nutrients for plant recover (Pereira et al., 2014a), protects soil from erosion and controls soil hydrological process as runoff, infiltration and water repellency (Cerda and Doerr, 2008; Bodi et al., 2012, Pereira et al., 2014b). Despite the recognition of ash impact and contribution to ecosystems recuperation, it is assumed that we still have little knowledge about the implications of ash in fire affected areas. Regarding this situation we wanted to improve our knowledge in this field and understand the state of the research about fire ash around world. The special issue about "The role of ash in fire affected ecosystems" currently in publication in CATENA born from the necessity of joint efforts, identify research gaps, and discuss future cooperation in this interdisciplinary field. This is the first special issue about fire ash in the international literature. In total it will be published 10 papers focused in different aspects of the impacts of ash in fire affected ecosystems from several parts of the world: • Fire reconstruction using charcoal particles (Burjachs and Espositio, in press) • Ash slurries impact on rheological properties of Runoff (Burns and Gabet, in press) • Methods to analyse ash conductivity and sorbtivity in the laboratory and in the field (Balfour et al., in press) • Termogravimetric and hydrological properties of ash (Dlapa et al. in press) • Effects of ash cover in water infiltration (Leon et al., in press) • Impact of ash in volcanic soils (Dorta Almenar et al., in press; Escuday et al., in press) • Ash PAH and Chemical extracts (Silva et al., in press) • Microbiology (Barreiro et al., in press; Lombao et al., in press) We believe that this special issue will contribute importantly to the better understanding of

  19. Lye From Wood Ash. What We Make. Science and Technology Education in Philippine Society.

    Science.gov (United States)

    Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

    With the high cost of gas and electricity, more people are turning to wood or charcoal for fuel. The ash that remains after the wood or charcoal has been thoroughly burned can be used to prepare lye. "Suman sa lihiya,""cuchinta," and soap can be made with the use of this lye. Procedures for making these materials as well as the…

  20. Major and trace elements in coal bottom ash at different oxy coal combustion conditions

    CSIR Research Space (South Africa)

    Oboirien, BO

    2014-09-01

    Full Text Available This paper presents a detailed study on the effect of temperature on the concentration of 27 major and trace elements in bottom ash generated from oxy fuel-combustion. The major elements are Na, Mg, Al, K, Ca and Fe and the minor and trace elements...

  1. Temporal evolution of wildfire ash and its implications for water pollution

    Science.gov (United States)

    Santin, Cristina; Doerr, Stefan H.; Otero, Xose L.; Chafer, Chris J.

    2015-04-01

    Ash, the burnt residue generated from combustion of vegetation, litter and surface soil, covers the ground after every wildfire. The effects of wildfire ash on the post-fire landscape are many and very diverse. It is a source of nutrients and can, therefore, help the recovery of vegetation after fire. Furthermore, in its initial state, the ash layer on the ground can protect the bare soil from rain splash erosion and can act as an adsorbent layer, preventing or delaying post-fire water erosion by runoff. However, when the adsorbent capability of the ash layer is exceeded, this highly erodible material can be transported into the hydrological network and be a major contributor to water contamination. Most previous studies on post-fire erosion and water contamination have focused on soil erosion and associated sediment transfer and overlooked the ash component or, when considered, ash has been included as an unidentified part of the eroded sediment. One of the reasons for overlooking this key post-fire component is the difficulty of ash sampling before it is lost by wind or water erosion or altered by aging on-site. Here we compare the water contamination potential of ash obtained from two fires in the dry eucalyptus forest environment of the Sydney tablelands, Australia: i) 'aged ash' produced during the severe Balmoral wildfire and sampled two months after the event (Jan. 2014) and ii) 'fresh ash' sampled immediately after a high-intensity experimental fire in the same region (Sept. 2014). At the time of sampling, neither of the ash types had been affected by water erosion, however, the aged ash had been subjected to rainfall events and, potentially, to wind erosion during the two months of exposure. Vegetation type, fuel loads and fire severity, determined using remote sensing and on-site observations, were comparable between both areas sampled. Ash physicochemical properties differed, with 'fresh ash' having higher pH and EC values and higher concentration of

  2. Emerald ash borer biocontrol in ash saplings: the potential for early stage recovery of North American ash

    Science.gov (United States)

    In many parts of North America, ash stands have been reduced by the emerald ash borer (Agrilus planipennis) invasion to a few surviving mature trees and young basal sprouts, saplings, and seedlings. Without a seed bank, ash tree recovery will require survival and maturation of these younger cohorts...

  3. Pulverizing Portraits

    DEFF Research Database (Denmark)

    Elias, Camelia

    on interdisciplinary approaches to poetry via visual aesthetics, poststructuralist literary and theoretical perspectives, and philosophy. Camelia Elias takes a look at what characterizes contemporary American prose poetry, namely an intensified awareness of being close to something. Poets such as Lynn Emanuel have...

  4. Geochemistry of ultra-fine and nano-compounds in coal gasification ashes: a synoptic view.

    Science.gov (United States)

    Kronbauer, Marcio A; Izquierdo, Maria; Dai, Shifeng; Waanders, Frans B; Wagner, Nicola J; Mastalerz, Maria; Hower, James C; Oliveira, Marcos L S; Taffarel, Silvio R; Bizani, Delmar; Silva, Luis F O

    2013-07-01

    The nano-mineralogy, petrology, and chemistry of coal gasification products have not been studied as extensively as the products of the more widely used pulverized-coal combustion. The solid residues from the gasification of a low- to medium-sulfur, inertinite-rich, volatile A bituminous coal, and a high sulfur, vitrinite-rich, volatile C bituminous coal were investigated. Multifaceted chemical characterization by XRD, Raman spectroscopy, petrology, FE-SEM/EDS, and HR-TEM/SEAD/FFT/EDS provided an in-depth understanding of coal gasification ash-forming processes. The petrology of the residues generally reflected the rank and maceral composition of the feed coals, with the higher rank, high-inertinite coal having anisotropic carbons and inertinite in the residue, and the lower rank coal-derived residue containing isotropic carbons. The feed coal chemistry determines the mineralogy of the non-glass, non-carbon portions of the residues, with the proportions of CaCO₃ versus Al₂O₃ determining the tendency towards the neoformation of anorthite versus mullite, respectively. Electron beam studies showed the presence of a number of potentially hazardous elements in nanoparticles. Some of the neoformed ultra-fine/nano-minerals found in the coal ashes are the same as those commonly associated with oxidation/transformation of sulfides and sulfates.

  5. Dust separation at high temperatures a method for cleaning fly ashes? Final report; Stoftavskiljning vid hoeg temperatur en metod foer rening av flygaska? Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Zintl, Frank [TPS Termiska Processer AB, Nykoeping (Sweden)

    2002-12-01

    An experimental study of separation of fly ashes by a filter at high temperatures, 300-650 deg C, with the purpose to study: Capture of heavy metals (Cd, Hg, Pb, Zn) in the fly ash; Relation between heavy metal capture and temperature; Relation between heavy metal capture and the availability of fuel chlorine. Pelletized forestry waste fuel was doped with heavy metals in two different forms. Pelletized Salix was also used, without doping. The study shows that: There is a strong inverse relation between the capture of heavy metals and the filter temperature; There is a strong relation between the availability of chlorine and the capture of heavy metals. Separation at 300-650 deg C gives much less heavy metals in the fly ash, however the ash is not clean enough to allow disposal in ordinary landfills. Thus, high temperature filtering does not seem to be a promising solution for producing 'clean' fly ash.

  6. Organic coal-water fuel: Problems and advances (Review)

    Science.gov (United States)

    Glushkov, D. O.; Strizhak, P. A.; Chernetskii, M. Yu.

    2016-10-01

    The study results of ignition of organic coal-water fuel (OCWF) compositions were considered. The main problems associated with investigation of these processes were identified. Historical perspectives of the development of coal-water composite fuel technologies in Russia and worldwide are presented. The advantages of the OCWF use as a power-plant fuel in comparison with the common coal-water fuels (CWF) were emphasized. The factors (component ratio, grinding degree of solid (coal) component, limiting temperature of oxidizer, properties of liquid and solid components, procedure and time of suspension preparation, etc.) affecting inertia and stability of the ignition processes of suspensions based on the products of coaland oil processing (coals of various types and metamorphism degree, filter cakes, waste motor, transformer, and turbine oils, water-oil emulsions, fuel-oil, etc.) were analyzed. The promising directions for the development of modern notions on the OCWF ignition processes were determined. The main reasons limiting active application of the OCWF in power generation were identified. Characteristics of ignition and combustion of coal-water and organic coal-water slurry fuels were compared. The effect of water in the composite coal fuels on the energy characteristics of their ignition and combustion, as well as ecological features of these processes, were elucidated. The current problems associated with pulverization of composite coal fuels in power plants, as well as the effect of characteristics of the pulverization process on the combustion parameters of fuel, were considered. The problems hindering the development of models of ignition and combustion of OCWF were analyzed. It was established that the main one was the lack of reliable experimental data on the processes of heating, evaporation, ignition, and combustion of OCWF droplets. It was concluded that the use of high-speed video recording systems and low-inertia sensors of temperature and gas

  7. Transcriptomic signatures of ash (Fraxinus spp. phloem.

    Directory of Open Access Journals (Sweden)

    Xiaodong Bai

    Full Text Available BACKGROUND: Ash (Fraxinus spp. is a dominant tree species throughout urban and forested landscapes of North America (NA. The rapid invasion of NA by emerald ash borer (Agrilus planipennis, a wood-boring beetle endemic to Eastern Asia, has resulted in the death of millions of ash trees and threatens billions more. Larvae feed primarily on phloem tissue, which girdles and kills the tree. While NA ash species including black (F. nigra, green (F. pennsylvannica and white (F. americana are highly susceptible, the Asian species Manchurian ash (F. mandshurica is resistant to A. planipennis perhaps due to their co-evolutionary history. Little is known about the molecular genetics of ash. Hence, we undertook a functional genomics approach to identify the repertoire of genes expressed in ash phloem. METHODOLOGY AND PRINCIPAL FINDINGS: Using 454 pyrosequencing we obtained 58,673 high quality ash sequences from pooled phloem samples of green, white, black, blue and Manchurian ash. Intriguingly, 45% of the deduced proteins were not significantly similar to any sequences in the GenBank non-redundant database. KEGG analysis of the ash sequences revealed a high occurrence of defense related genes. Expression analysis of early regulators potentially involved in plant defense (i.e. transcription factors, calcium dependent protein kinases and a lipoxygenase 3 revealed higher mRNA levels in resistant ash compared to susceptible ash species. Lastly, we predicted a total of 1,272 single nucleotide polymorphisms and 980 microsatellite loci, among which seven microsatellite loci showed polymorphism between different ash species. CONCLUSIONS AND SIGNIFICANCE: The current transcriptomic data provide an invaluable resource for understanding the genetic make-up of ash phloem, the target tissue of A. planipennis. These data along with future functional studies could lead to the identification/characterization of defense genes involved in resistance of ash to A. planipennis

  8. Settling characteristics of some Indian fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Jain, M.K.; Sastry, B.S. [Indian Institute of Technology, Kharapur (India). Dept. of Mining Engineering

    2003-07-01

    The paper examines the aspects of the solid liquid separation (settling characteristics) of some of the fly ash obtained from coal-fired power plants in India. The application of a coagulating or flocculating agent (polymer) to improve the two properties as indicated is a typical industrial practice. The sources for this study comprise of fly ash, pond ash, and bottom ash and the settling characteristics are studied in conjunction with the flocculating agent polyacrylamide. 4 refs., 4 figs., 3 tabs.

  9. Gasification of high ash, high ash fusion temperature bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  10. Gasification of high ash, high ash fusion temperature bituminous coals

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  11. The effect of palm kernel shell ash on the mechanical properties of as-cast aluminium alloy matrix composites

    Directory of Open Access Journals (Sweden)

    Isiaka Oluwole OLADELE

    2016-06-01

    Full Text Available The present work describes the effect of palm kernel shell ash (PKSA as reinforcement on the mechanical properties of As-cast aluminium alloy. Recycled aluminium alloy from cylinder of an automotive engine block was degreased by using premium motor spirit (PMS also known as petrol, washed thoroughly with soap and water and sun dried for 5 days. The palm kernel shell was screened of dirt and other unwanted foreign materials before being roasted in furnace. The ash was further pulverized by laboratory ball mill machine followed by sieving to obtain particle sizes of 106 µm and divided into two parts. One portion was treated with NaOH solution while the other part was left as untreated before they are used to reinforced molten aluminium alloy in predetermined proportions. The newly developed composites were characterized with respect to their mechanical properties in response to the tests that were carried out on them. The results indicate that palm kernel shell ash can be used as potential reinforcing material for automobile applications.

  12. DURABILITY OF HARDENED FLY ASH PASTE

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The mechanical properties and durability ( mainly frost-resistance and carbonation resistance ) of fly ash-CaO-CaSO4 .2H2O hardened paste are studied. The relationship among durability of harden ed fly ash paste, the quantity and distribution of hydrates and the initial p aste texture of hardened fly ash paste is presented.

  13. A method for treating bottom ash

    NARCIS (Netherlands)

    Rem, P.C.; Van Craaikamp, H.; Berkhout, S.P.M.; Sierhuis, W.; Van Kooy, L.A.

    2007-01-01

    A method for treating bottom ash from a waste incineration plant. The invention relates in particular to a method for treating bottom ash from a domestic waste incineration plant. In accordance with the invention bottom ash having a size ranging up to 2 mm is treated by removing a previously determi

  14. Optimize to pulverizing system control method for the Indonesian high moisture lignite coal%针对印尼高水分褐煤的制粉系统优化控制方法

    Institute of Scientific and Technical Information of China (English)

    程学安

    2012-01-01

      This paper introduces the main problem of the lignite pulverizing system of large power stations, the use of actual production experience in Indonesia, for high-moisture lignite explosive the drying capacity demand large, the optimal control method. Domestic medium-speed mill boilers fueled with high moisture lignite certain reference.%  该文介绍了现有燃用褐煤的大型电站的制粉系统出现的主要问题,并利用在印尼实际的生产经验,针对高水分褐煤易爆炸,干