WorldWideScience

Sample records for coal combustion residues

  1. Radioactivity of combustion residues from coal-fired power stations

    International Nuclear Information System (INIS)

    Vom Berg, W.; Puch, K.H.

    1996-01-01

    Each year in Germany, about 18 mill. t of combustion residues are produced from the combustion of bituminous coal and lignite. They are utilized to a great extent in the construction industry and in mining. During the combustion of coal, the radio-nuclides remain predominantly in the ash. The radionuclide concentration in lignite ash is within the range of that in natural soil. The combustion residues of bituminous coal contain radio-nuclides of a similar order of magnitude as also can occur in natural rock. The utilization of combustion residues in construction materials makes a negligible contribution to radiation exposure through retention in buildings. (orig.) [de

  2. Methodology for Evaluating Encapsulated Beneficial Uses of Coal Combustion Residuals

    Science.gov (United States)

    The primary purpose of this document is to present an evaluation methodology developed by the EPA for making determinations about environmental releases from encapsulated products containing coal combustion residuals.

  3. Fluidized bed and pulverized coal combustion residues for secondary pavements

    International Nuclear Information System (INIS)

    Ghafoori, N.; Diawara, H.; Wang, L.

    2009-01-01

    The United States produced nearly 125 million tons of coal combustion products in 2006. These by-products include fly ash, flue gas desulphurization materials, bottom ash, boiler slag, and other power plant by-products. The expense associated with waste disposal, lack of disposal sites, and significant environmental damage linked with the disposal of coal combustion residues have encouraged innovative utilization strategies such as the fluidized bed combustion (FBC) unit. This paper presented the results of a laboratory investigation that examined the properties of composites developed with different proportions of pre-conditioned FBC spent bed, pulverized coal combustion fly ash, natural fine aggregate, and Portland cement. The purpose of the study was to examine the extent to which the by-product composites could replace currently used materials in secondary roads. The paper presented the research objectives and experimental programs, including matrix constituent and proportions; mixture proportions; and mixing, curing, sampling, and testing. The discussion of results centered around compressive strength and expansion by internal sulfate attack. It was concluded that with proper proportioning, by-products of pulverized and fluidized bed combustion promote binding of sand particles and provide adequate strength under various curing and moisture conditions 4 refs., 6 tabs.

  4. Selective leaching of coal and coal combustion solid residues

    Energy Technology Data Exchange (ETDEWEB)

    O`Keefe, C.A. [University of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center

    1996-12-31

    Selective leaching of coal and fly ash were carried out in order to predict the potential for environmental impact as well as other properties related to the aqueous solubility of inorganic constituents. Chemical fractionation can help to identify the distribution of major, minor, and trace constituents. 35 refs., 10 tabs.

  5. Naturally Occurring Radioactive Materials in Uranium-Rich Coals and Associated Coal Combustion Residues from China.

    Science.gov (United States)

    Lauer, Nancy; Vengosh, Avner; Dai, Shifeng

    2017-11-21

    Most coals in China have uranium concentrations up to 3 ppm, yet several coal deposits are known to be enriched in uranium. Naturally occurring radioactive materials (NORM) in these U-rich coals and associated coal combustion residues (CCRs) have not been well characterized. Here we measure NORM (Th, U, 228 Ra, 226 Ra, and 210 Pb) in coals from eight U-rich coal deposits in China and the associated CCRs from one of these deposits. We compared NORM in these U-rich coals and associated CCRs to CCRs collected from the Beijing area and natural loess sediments from northeastern China. We found elevated U concentrations (up to 476 ppm) that correspond to low 232 Th/ 238 U and 228 Ra/ 226 Ra activity ratios (≪1) in the coal samples. 226 Ra and 228 Ra activities correlate with 238 U and 232 Th activities, respectively, and 226 Ra activities correlate well with 210 Pb activities across all coal samples. We used measured NORM activities and ash yields in coals to model the activities of CCRs from all U-rich coals analyzed in this study. The activities of measured and modeled CCRs derived from U-rich coals exceed the standards for radiation in building materials, particularly for CCRs originating from coals with U > 10 ppm. Since beneficial use of high-U Chinese CCRs in building materials is not a suitable option, careful consideration needs to be taken to limit potential air and water contamination upon disposal of U- and Ra-rich CCRs.

  6. Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard

    Science.gov (United States)

    This page contains documents related to the evaluation of coal combustion residual beneficial use of fly ash concrete and FGD gypsum wallboard including the evaluation itself and the accompanying appendices

  7. Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions

    Science.gov (United States)

    Abstract for presentation on Characterizing the Leaching Behavior of Coal Combustion Residues using the Leaching Environmental Assessment Framework (LEAF) to Inform Future Management Decisions. The abstract is attached.

  8. Management of high sulfur coal combustion residues, issues and practices: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Chugh, Y.P.; Beasley, G.A. [eds.

    1994-10-01

    Papers presented at the following sessions are included in this proceedings: (1) overview topic; (2) characterization of coal combustion residues; (3) environmental impacts of residues management; (4) materials handling and utilization, Part I; and (5) materials handling and utilization, Part II. Selected paper have been processed separately for inclusion in the Energy Science and Technology Database.

  9. Characterization, leachability and valorization through combustion of residual chars from gasification of coals with pine.

    Science.gov (United States)

    Galhetas, Margarida; Lopes, Helena; Freire, Márcia; Abelha, Pedro; Pinto, Filomena; Gulyurtlu, Ibrahim

    2012-04-01

    This paper presents the study of the combustion of char residues produced during co-gasification of coal with pine with the aim of characterizing them for their potential use for energy. These residues are generally rich in carbon with the presence of other elements, with particular concern for heavy metals and pollutant precursors, depending on the original fuel used. The evaluation of environmental toxicity of the char residues was performed through application of different leaching tests (EN12457-2, US EPA-1311 TCLP and EA NEN 7371:2004). The results showed that the residues present quite low toxicity for some of pollutants. However, depending on the fuel used, possible presence of other pollutants may bring environmental risks. The utilization of these char residues for energy was in this study evaluated, by burning them as a first step pre-treatment prior to landfilling. The thermo-gravimetric analysis and ash fusibility studies revealed an adequate thermochemical behavior, without presenting any major operational risks. Fluidized bed combustion was applied to char residues. Above 700°C, very high carbon conversion ratios were obtained and it seemed that the thermal oxidation of char residues was easier than that of the coals. It was found that the char tendency for releasing SO(2) during its oxidation was lower than for the parent coal, while for NO(X) emissions, the trend was observed to increase NO(X) formation. However, for both pollutants the same control techniques might be applied during char combustion, as for coal. Furthermore, the leachability of ashes resulting from the combustion of char residues appeared to be lower than those produced from direct coal combustion. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Instrumental neutron activation analysis of coal and its combustion residues from a power plant

    International Nuclear Information System (INIS)

    Lim, J.M.; Jeong, J.H.; Lee, J.H.

    2013-01-01

    A growing demand of electrical energy derived from coal combustion led to a significant increase of coal ash as residues. Approximately 70 % of the fly ashes are recycled, while most of the bottom ashes have been land-filled in the ash pond in Korea. In this work, to evaluate the potential impacts of the residues from a coal power plant on the environment, its inorganic elemental components were determined by INAA and PGAA. Coal ash samples were collected from the biggest power plant complex in Korea. These samples were analyzed by using the NAA facilities in the HANARO research reactor of the Korea Atomic Energy Research Institute. A total of 31 elements were analyzed in the samples, and certified reference materials were used for the analytical quality control. The enrichment status of a given metal in fuel coal and ashes was investigated by its concentration ratio. In order to assess the impact of the coal combustion residues on ecosystem, their concentrations determined for each respective type of the samples were compared to both reference data and nearby beach sand samples. (author)

  11. Leaching and soil/groundwater transport of contaminants from coal combustion residues

    International Nuclear Information System (INIS)

    Hjelmar, O.; Hansen, E.A.; Larsen, F.; Thomassen, H.

    1992-01-01

    In this project the results of accelerated laboratory leaching tests on coal fly ash and flue gas desulfurization (FGD) products from the spray dryer absorption process (SDA) were evaluated by comparison to the results of large scale lysimeter leaching tests on the same residues. The mobility of chromium and molybdenum - two of the kev contaminants of coal combustion residue leachates - in various typical soil types was investigated by batch and column methods in the laboratory. Some of the results were confirmed by field observations at an old coal fly ash disposal site and by a lysimeter attenuation test with coal fly ash leachate on a clayed till. A large number of groundwater transport models and geochemical models were reviewed, and two of the models (Gove-Stollenwerk and CHMTRNS) were modified and adjusted and used to simulate column attenuation tests performed in the laboratory. One of the models (Grove-Stollenwerk) was used to illustrate a recommended method of environmental impact assessment, using lysimeter leaching data and laboratory column attenuation data to describe the emission and migration of Mo from a coal fly ash disposal site

  12. Disposing of coal combustion residues in inactive surface mines: Effects on water quality

    International Nuclear Information System (INIS)

    Kim, A.G.; Ackman, T.E.

    1994-01-01

    The disposal of coal combustion residues (CCR) in surface and underground coal mines can provide a stable, low-maintenance alternative to landfills, benefiting the mining and electric power industries. The material may be able to improve water quality at acid generating abandoned or reclaimed coal mine sites. Most combustion residues are alkaline, and their addition to the subsurface environment could raise the pH, limiting the propagation of pyrite oxidizing bacteria and reducing the rate of acid generation. Many of these CCR are also pozzolanic, capable of forming cementitious grouts. Grouts injected into the buried spoil may decrease its permeability and porosity, diverting water away from the pyritic material. Both mechanisms, alkaline addition and water diversion, are capable of reducing the amount of acid produced at the disposal site. The US Bureau of Mines is cooperating in a test of subsurface injection of CCR into a reclaimed surface mine. Initially, a mixture of fly ash, lime, and acid mine drainage (AMD) sludge was injected. Lime was the source of calcium for the formation of the pozzolanic grout. Changes in water quality parameters (pH, acidity, anions, and trace metals) in water samples from wells and seeps indicate a small but significant improvement after CCR injection. Changes in the concentration of heavy metals in the water flowing across the site were apparently influenced by the presence of flyash

  13. Solid-state nuclear magnetic resonance studies of phosphorus and boron in coals and combustion residues

    Energy Technology Data Exchange (ETDEWEB)

    Burchill, P.; Howarth, O.W.; Richards, D.G.; Sword, B.J. (British Coal Corporation, Stoke Orchard (UK). Coal Research Establishment)

    1990-04-01

    Solid-state nuclear magnetic resonance spectroscopy with magic angle spinning (MAS-n.m.r.) was used to study the occurrence of phosphorus and boron in coal, and their fate on combustion. These elements are only minor components of coal, but may significantly influence the utilization properties. {sup 31} P MAS-n.m.r. spectroscopy has confirmed that phosphorus is present in coal predominantly as apatite. This mineral is thermally stable under oxidizing conditions, and survives largely unaltered in high temperature ashes. However, under the semi-reducing bed conditions of certain stoker-fired boilers, it may be decomposed, volatilizing the phosphorus. The {sup 31}P MAS-n.m.r. spectra of bonded deposits show phosphorus in a markedly different coordination environment to that in apatite, the chemical shift suggesting aluminium phosphate or boron phosphate. {sup 11}B MAS-n.m.r. spectra of coals exhibit resonances due to both trigonal and tetrahedrally coordinated boron. Trigonal boron is probably present as tourmaline, but the nature of the tetrahedral boron is less certain; it may be held in tetrahedral sites within certain clay minerals. In common with phosphorus, boron may be volatilized during combustion. The {sup 11}B MAS-n.m.r. spectra of bonded deposits show a tetrahedral resonance with a chemical shift quite consistent with that of boron phosphate. 39 refs., 9 figs., 5 tabs.

  14. Evaluating the thermal stability of mercury and other metals in coal combustion residues used in the production of cement clinker, asphalt, and wallboard

    Science.gov (United States)

    Research is underway by the U.S. Environmental Protection Agency (EPA) to document any changes that may occur to coal combustion residues (CCRs) as a result of implementation of mercury and multiipollutant control technology at coal-fired power plants. This work was cited as a pr...

  15. Increase in efficiency and reduction of generation cost at hard coal-fired power plants. Post-combustion of combustion residues from co-firing of RDF and biomass during dry ash removal

    Energy Technology Data Exchange (ETDEWEB)

    Baur, Guenter [Magaldi Power GmbH, Esslingen (Germany); Spindeldreher, Olaf [RWE Generation SE, Werne (Germany); RWE Generation SE, Essen (Germany)

    2013-09-01

    Secondary as well as substitute fuels are being used in hard coal-fired power plants to improve efficiency and to enlarge fuel flexibility. However, grinding and firing systems of the existing coal-fired plants are not designed for those co-fuels. Any deterioration of the combustion performance would reduce the power output and increase ash disposal costs by increased content of combustion residues. The application of air-cooled ash removal, with simultaneous and controlled post-combustion of unburned residues on the conveyor belt, enlarges the furnace and maintains combustion efficiency even with different fuel qualities. Plant efficiency can also be increased through heat recovery. (orig.)

  16. Recovery of Trace and Heavy Metals from Coal Combustion Residues for Reuse and Safe Disposal: A Review

    Science.gov (United States)

    Kumar, Ashvani; Samadder, Sukha Ranjan; Elumalai, Suresh Pandian

    2016-09-01

    The safe disposal of coal combustion residues (CCRs) will remain a major public issue as long as coal is used as a fuel for energy production. Both dry and wet disposal methods of CCRs create serious environmental problems. The dry disposal method creates air pollution initially, and the wet disposal method creates water pollution as a result of the presence of trace and heavy metals. These leached heavy metals from fly ash may become more hazardous when they form toxic compounds such as arsenic sulfite (As2S3) and lead nitrate (N2O6Pb). The available studies on trace and heavy metals present in CCRs cannot ensure environmentally safe utilization. In this work, a novel approach has been offered for the retrieval of trace and heavy metals from CCRs. If the proposed method becomes successful, then the recovered trace and heavy metals may become a resource and environmentally safe use of CCRs may be possible.

  17. Emission factors of polycyclic and nitro-polycyclic aromatic hydrocarbons from residential combustion of coal and crop residue pellets.

    Science.gov (United States)

    Yang, Xiaoyang; Liu, Shijie; Xu, Yisheng; Liu, Yu; Chen, Lijiang; Tang, Ning; Hayakawa, Kazuichi

    2017-12-01

    Polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) are toxic pollutants mainly produced during fossil fuel combustion. Domestic coal stoves, which emit large amounts of PAHs and NPAHs, are widely used in the Chinese countryside. In this study, emission factors (Efs) for 13 PAH species and 21 NPAH species for four raw coal (three bituminous and one anthracite), one honeycomb briquette, and one crop residue pellet (peanut hulls) samples burned in a typical Chinese rural cooking stove were determined experimentally. The PAH and NPAH Efs for the six fuels were 3.15-49 mg/kg and 0.32-100 μg/kg, respectively. Peanut hulls had very high Efs for both PAHs and NPAHs, and honeycomb briquettes had the lowest Efs. 2-Nitropyrene and 2-nitrofluoranthene, which are NPAHs typically found in secondary organic aerosol, were detected in the emissions from some fuels, suggesting that chemical reactions may have occurred in the dilution tunnel between the flue gas leaving the stove and entering the sampler. The 1-nitropyrene to pyrene diagnostic ratios for coal and peanut hulls were 0.0001 ± 0.0001 and 0.0005, respectively. These were in the same order of magnitude as reference ratios for emissions during coal combustion. The 6-nitrobenzo[a]pyrene to benzo[a]pyrene ratios for the fuels were determined, and the ratios for coal and peanut hulls were 0.0010 ± 0.0001 and 0.0014, respectively. The calculated potential toxic risks indicated that peanut hull emissions were very toxic, especially in terms of NPAHs, compared with emissions from the other fuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Thermogravimetric analysis of the behavior of sub-bituminous coal and cellulosic ethanol residue during co-combustion.

    Science.gov (United States)

    Buratti, C; Barbanera, M; Bartocci, P; Fantozzi, F

    2015-06-01

    The influence of the addition of cellulosic ethanol residue (CER) on the combustion of Indonesian sub-bituminous coal was analyzed by non isothermal thermo-gravimetric analysis (TGA). The effect of blends ratio (5%, 10%, 15% and 20%), interaction mechanism, and heating rate (5°C/min, 10°C/min, 15°C/min, 20°C/min) on the combustion process was studied. The results show that the increase of the blending ratio allows to achieve the increase of the combustibility index from 7.49E-08 to 5.26E-07 at the blending ratio of 20%. Two types of non-isothermal kinetic analysis methods (Ozawa-Flynn-Wall and Vyazovkin) were also applied. Results indicate that the activation energy of the blends decreases with increasing the conversion rate. In particular, the blending ratio of 20% confirms to have the better combustion performance, with the average value of the activation energy equal to 41.10 kJ/mol obtained by Ozawa-Flynn-Wall model and 31.17 kJ/mol obtained by Vyazovkin model. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Coal combustion technology in China

    International Nuclear Information System (INIS)

    Huang, Z.X.

    1994-01-01

    Coal is the most important energy source in China, the environmental pollution problem derived from coal burning is rather serious in China. The present author discusses coal burning technologies both in boilers and industrial furnaces and their relations with environmental protection problems in China. The technological situations of Circulating Fluidized Bed Coal Combustor, Pulverized Coal Combustor with Aerodynamic Flame Holder and Coal Water Slurry Combustion have been discussed here as some of the interesting problems in China only. (author). 3 refs

  20. Growth and developmental effects of coal combustion residues on Southern Leopard Frog (Rana sphenocephala) tadpoles exposed throughout metamorphosis

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J.D.; Peterson, V.A.; Mendonca, M.T. [Auburn University, Auburn, AL (United States). Dept. for Biological Science

    2008-09-15

    The effects of aquatic deposition of coal combustion residues (CCRs) on amphibian life histories have been the focus of many recent studies. In summer 2005, we raised larval Southern Leopard Frogs, Rana sphenocephala, on either sand or CCR substrate (approximately 1 cm deep within plastic bins) and documented effects of sediment type on oral disc condition, as well as time to, mass at, and total body length at key developmental stages, including metamorphosis (Gosner stages (GS) 37, 42, and 46). We found no significant difference in mortality between the two treatments and mortality was relatively low (eight of 48 in the control group and four of 48 in the CCR group). Ninety percent of exposed tadpoles displayed oral disc abnormalities, while no control individuals displayed abnormalities. Tadpoles raised on CCR-contaminated sediment had decreased developmental rates and weighed significantly less at all developmental stages, on average, when compared to controls. The CCR treatment group was also significantly shorter In length than controls at the completion of metamorphosis (GS 46). Collectively, these findings are the most severe sub-lethal effects noted for any amphibian exposed to CCRs to date. More research is needed to understand how these long term effects may contribute to the dynamics of local amphibian populations.

  1. Exposure to coal combustion residues during metamorphosis elevates corticosterone content and adversely affects oral morphology, growth, and development in Rana sphenocephala

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J.D.; Peterson, V.A.; Mendonca, M.T. [Auburn University, Auburn, AL (USA). Dept. of Biological Science

    2009-01-15

    Coal combustion residues (CCRs) are documented to negatively impact oral morphology, growth, and development in larval amphibians. It is currently unclear what physiological mechanisms may mediate these effects. Corticosterone, a glucocorticoid hormone, is a likely mediator because when administered exogenously it, like CCRs, also negatively influences oral morphology, growth, and development in larval amphibians. In an attempt to identify if corticosterone mediates these effects, we raised larval Southern Leopard Frogs, Rana sphenocephala, on either sand or CCR substrate and documented effects of sediment type on whole body corticosterone, oral morphology, and time to and mass at key metamorphic stages. Coal combustion residue treated tadpoles contained significantly more corticosterone than controls throughout metamorphosis. However, significantly more oral abnormalities occurred early in metamorphosis when differences in corticosterone levels between treatments were minimal. Overall, CCR-treated tadpoles took significantly more time to transition between key stages and gained less mass between stages than controls, but these differences between treatments decreased during later stages when corticosterone differences between treatments were greatest. Our results suggest endogenous increase in corticosterone content and its influence on oral morphology, growth and development is more complex than previously thought.

  2. Coal combustion waste management study

    International Nuclear Information System (INIS)

    1993-02-01

    Coal-fired generation accounted for almost 55 percent of the production of electricity in the United States in 1990. Coal combustion generates high volumes of ash and flue gas desulfurization (FGD) wastes, estimated at almost 90 million tons. The amount of ash and flue gas desulfurization wastes generated by coal-fired power plants is expected to increase as a result of future demand growth, and as more plants comply with Title IV of the 1990 Clean Air Act Amendments. Nationwide, on average, over 30 percent of coal combustion wastes is currently recycled for use in various applications; the remaining percentage is ultimately disposed in waste management units. There are a significant number of on-site and off-site waste management units that are utilized by the electric utility industry to store or dispose of coal combustion waste. Table ES-1 summarizes the number of disposal units and estimates of waste contained at these unites by disposal unit operating status (i.e, operating or retired). Further, ICF Resources estimates that up to 120 new or replacement units may need to be constructed to service existing and new coal capacity by the year 2000. The two primary types of waste management units used by the industry are landfills and surface impoundments. Utility wastes have been exempted by Congress from RCRA Subtitle C hazardous waste regulation since 1980. As a result of this exemption, coal combustion wastes are currently being regulated under Subtitle D of RCRA. As provided under Subtitle D, wastes not classified as hazardous under Subtitle C are subject to State regulation. At the same time Congress developed this exemption, also known as the ''Bevill Exclusion,'' it directed EPA to prepare a report on coal combustion wastes and make recommendations on how they should be managed

  3. Oxy-coal Combustion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J. [Univ. of Utah, Salt Lake City, UT (United States); Eddings, E. [Univ. of Utah, Salt Lake City, UT (United States); Lighty, J. [Univ. of Utah, Salt Lake City, UT (United States); Ring, T. [Univ. of Utah, Salt Lake City, UT (United States); Smith, P. [Univ. of Utah, Salt Lake City, UT (United States); Thornock, J. [Univ. of Utah, Salt Lake City, UT (United States); Y Jia, W. Morris [Univ. of Utah, Salt Lake City, UT (United States); Pedel, J. [Univ. of Utah, Salt Lake City, UT (United States); Rezeai, D. [Univ. of Utah, Salt Lake City, UT (United States); Wang, L. [Univ. of Utah, Salt Lake City, UT (United States); Zhang, J. [Univ. of Utah, Salt Lake City, UT (United States); Kelly, K. [Univ. of Utah, Salt Lake City, UT (United States)

    2012-01-06

    The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol.

  4. Study of mechanically activated coal combustion

    Directory of Open Access Journals (Sweden)

    Burdukov Anatolij P.

    2009-01-01

    Full Text Available Combustion and air gasification of mechanically activated micro-ground coals in the flux have been studied. Influence of mechanically activated methods at coals grinding on their chemical activeness at combustion and gasification has been determined. Intense mechanical activation of coals increases their chemical activeness that enables development of new highly boosted processing methods for coals with various levels of metamorphism.

  5. Combustion demonstration plant in circulant fluidized bed of residual coal; Planta de Demostracion de Combustion en Lecho Fluido Circulante de Carbones Residuales

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This report incorporates a summary of the operation results during the period of demonstration after started up. The report pretend to give an overview of the operation conditions along of the first year: Running hours, availability, electricity production, shooting downs, incidences, efficiency, fuel characteristics influence, pollutants emissions and standards comparations, etc. The main operation conclusions are: High availability, great number of running hours at full equivalent load; some months even over 100% regarding time scheduled. High reduction of gaseous emissions, really very low respecting the required by the applicable standards. It has been developed the engineering of a prototype project, by 30MW, using mixtures of solid fuels, residues and coals. (Author)

  6. Management of coal combustion wastes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-02-01

    It has been estimated that 780 Mt of coal combustion products (CCPs) were produced worldwide in 2010. Only about 53.5% were utilised, the rest went to storage or disposal sites. Disposal of coal combustion waste (CCW) on-site at a power plant may involve decades-long accumulation of waste, with hundreds of thousands, if not millions, of tonnes of dry ash or wet ash slurry being stored. In December 2008, a coal combustion waste pond in Kingston, Tennessee, USA burst. Over 4 million cubic metres of ash sludge poured out, burying houses and rivers in tonnes of toxic waste. Clean-up is expected to continue into 2014 and will cost $1.2 billion. The incident drew worldwide attention to the risk of CCW disposal. This caused a number of countries to review CCW management methods and regulations. The report begins by outlining the physical and chemical characteristics of the different type of ashes generated in a coal-fired power plant. The amounts of CCPs produced and regulations on CCW management in selected countries have been compiled. The CCW disposal methods are then discussed. Finally, the potential environmental impacts and human health risks of CCW disposal, together with the methods used to prevent them, are reviewed.

  7. Effects of coal combustion residues on survival, antioxidant potential, and genotoxicity resulting from full-lifecycle exposure of grass shrimp (Palaemonetes pugio Holthius)

    International Nuclear Information System (INIS)

    Kuzmick, Danika M.; Mitchelmore, Carys L.; Hopkins, William A.; Rowe, Christopher L.

    2007-01-01

    Coal combustion residues (CCRs), largely derived from coal-fired electrical generation, are rich in numerous trace elements that have the potential to induce sublethal effects including oxidative stress, alterations in antioxidant status and DNA single strand breaks (SSB). CCRs are frequently discharged into natural and man-made aquatic systems. As the effects of CCRs have received relatively little attention in estuarine systems, the estuarine grass shrimp, Palaemonetes pugio, was chosen for this study. Grass shrimp were exposed in the laboratory to CCR-enriched sediments and food over a full life cycle. Survival to metamorphosis was significantly reduced in CCR-exposed larvae (17 ± 4 versus 70 ± 13% in the controls) but not in the juveniles or adults. The COMET assay, a general but sensitive assay for genotoxicity, was used to quantify DNA SSB in the adults. Total antioxidant potential was examined to assess the overall antioxidant scavenging capacity of CCR-exposed and non-exposed adult grass shrimp. Grass shrimp exposed to CCR significantly accumulated selenium and cadmium compared to unexposed shrimp, although an inverse relationship was seen for mercury accumulation. Chronic CCR exposure caused DNA SSB in hepatopancreas cells, as evidenced by the significantly increased percent tail DNA, tail moment, and tail length as compared to reference shrimp. However, no significant difference was observed in total antioxidant potential. Our findings suggest that genotoxicity may be an important mode of toxicity of CCR, and that DNA SSB may serve as a useful biomarker of exposure and effect of this very common, complex waste stream

  8. Effects of coal combustion residues on survival, antioxidant potential, and genotoxicity resulting from full-lifecycle exposure of grass shrimp (Palaemonetes pugio Holthius)

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmick, Danika M.; Mitchelmore, Carys L.; Rowe, Christopher L. [University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 1, Williams Street, PO Box 38, Solomons, MD, 20688 (United States); Hopkins, William A. [Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, 100 Cheatham Hall, Blacksburg, VA (United States)

    2007-02-01

    Coal combustion residues (CCRs), largely derived from coal-fired electrical generation, are rich in numerous trace elements that have the potential to induce sublethal effects including oxidative stress, alterations in antioxidant status and DNA single strand breaks (SSB). CCRs are frequently discharged into natural and man-made aquatic systems. As the effects of CCRs have received relatively little attention in estuarine systems, the estuarine grass shrimp, Palaemonetes pugio, was chosen for this study. Grass shrimp were exposed in the laboratory to CCR-enriched sediments and food over a full life cycle. Survival to metamorphosis was significantly reduced in CCR-exposed larvae (17 {+-} 4 versus 70 {+-} 13% in the controls) but not in the juveniles or adults. The COMET assay, a general but sensitive assay for genotoxicity, was used to quantify DNA SSB in the adults. Total antioxidant potential was examined to assess the overall antioxidant scavenging capacity of CCR-exposed and non-exposed adult grass shrimp. Grass shrimp exposed to CCR significantly accumulated selenium and cadmium compared to unexposed shrimp, although an inverse relationship was seen for mercury accumulation. Chronic CCR exposure caused DNA SSB in hepatopancreas cells, as evidenced by the significantly increased percent tail DNA, tail moment, and tail length as compared to reference shrimp. However, no significant difference was observed in total antioxidant potential. Our findings suggest that genotoxicity may be an important mode of toxicity of CCR, and that DNA SSB may serve as a useful biomarker of exposure and effect of this very common, complex waste stream. (author)

  9. Kinetics of gasification and combustion of residues, biomass and coal in a bubbling fluidized bed; Die Kinetik der Vergasung und Verbrennung unterschiedlicher Abfaelle, Biomassen und Kohlen in der blasenbildenden Wirbelschicht

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, S; Krumm, W [Siegen Univ. (Gesamthochschule) (Germany). Lehrstuhl fuer Energie- und Umweltverfahrenstechnik

    1998-09-01

    The combustion and gasification characteristics of Rhenish brown coal, domestic waste, waste plastics, wood and sewage sludge were investigated in a bubbling atmospheric fluidized bed in the laboratory scale. The materials were pyrolyzed in the fluidized bed in a nitrogen atmosphere. The residual coke was combuted in the presence of oxygen with varying operating parameters or else gasified in the presence of carbon dioxide. The different materials were characterized by global combustion rates, and kinetic parameters were determined for residual coke combustion. (orig.) [Deutsch] Das Verbrennungs- und Vergasungsverhalten von Rheinischer Braunkohle, Hausmuell, Restkunststoff, Holz und Klaerschlamm wurde in einer blasenbildenden, atmosphaerischen Laborwirbelschicht untersucht. Die Einsatzstoffe wurden in der mit Stickstoff fluidisierten Wirbelschicht pyrolysiert. Der verbleibende Restkoks wurde anschliessend unter Variation der Betriebsparameter mit Sauerstoff verbrannt oder mit Kohlendioxid vergast. Die unterschiedlichen Einsatzstoffe wurden durch globale Vebrennungsraten charakterisiert. Fuer die Restkoksverbrennung wurden kinetische Parameter ermittelt. (orig.)

  10. Coal Combustion Products Extension Program

    Energy Technology Data Exchange (ETDEWEB)

    Tarunjit S. Butalia; William E. Wolfe

    2006-01-11

    This final project report presents the activities and accomplishments of the ''Coal Combustion Products Extension Program'' conducted at The Ohio State University from August 1, 2000 to June 30, 2005 to advance the beneficial uses of coal combustion products (CCPs) in highway and construction, mine reclamation, agricultural, and manufacturing sectors. The objective of this technology transfer/research program at The Ohio State University was to promote the increased use of Ohio CCPs (fly ash, FGD material, bottom ash, and boiler slag) in applications that are technically sound, environmentally benign, and commercially competitive. The project objective was accomplished by housing the CCP Extension Program within The Ohio State University College of Engineering with support from the university Extension Service and The Ohio State University Research Foundation. Dr. Tarunjit S. Butalia, an internationally reputed CCP expert and registered professional engineer, was the program coordinator. The program coordinator acted as liaison among CCP stakeholders in the state, produced information sheets, provided expertise in the field to those who desired it, sponsored and co-sponsored seminars, meetings, and speaking at these events, and generally worked to promote knowledge about the productive and proper application of CCPs as useful raw materials. The major accomplishments of the program were: (1) Increase in FGD material utilization rate from 8% in 1997 to more than 20% in 2005, and an increase in overall CCP utilization rate of 21% in 1997 to just under 30% in 2005 for the State of Ohio. (2) Recognition as a ''voice of trust'' among Ohio and national CCP stakeholders (particularly regulatory agencies). (3) Establishment of a national and international reputation, especially for the use of FGD materials and fly ash in construction applications. It is recommended that to increase Ohio's CCP utilization rate from 30% in 2005 to

  11. Coal slurry combustion and technology. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    Volume II contains papers presented at the following sessions of the Coal Slurry Combustion and Technology Symposium: (1) bench-scale testing; (2) pilot testing; (3) combustion; and (4) rheology and characterization. Thirty-three papers have been processed for inclusion in the Energy Data Base. (ATT)

  12. Co-combustion of risk husk with coal in a fluidized bed

    International Nuclear Information System (INIS)

    Ghani, A.K.; Alias, A.B.; Savory, R.M.; Cliffe, K.R.

    2006-01-01

    Power generation from biomass is an attractive technology which utilizes agricultural residue waste. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from agricultural residues (rice husk) was co-fired with coal in a 0.15 m diameter and 2.3 m high fluidized bed combustor. The combustion efficiency and CO emissions were studied and compared with those for pure coal combustion. Biomass waste with up to 70% mass fraction can be co-combusted in a fluidized bed combustor designed for coal combustion with a maximum drop of efficiency of 20% depending upon excess air levels. CO levels fluctuated between 200-700 ppm were observed when coal is added. It is evident from this research that efficient co-firing of rice husk with coal can be achieved with minimum modification of existing coal-fired boilers. (Author)

  13. Influence of Coal Quality on Combustion Performance

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der; Glarborg, Peter; Dam-Johansen, Kim

    1998-01-01

    mixing pattern on NO formation under these conditions. Emissions from the opposed fired plant with all combustion air introduced through the burners could only be qualitatively reproduced by the pilot furnace. Under single stage conditions the test rig provided higher NO levels. Carbon in ash levels did...... not show any correlation between the coals and the furnaces. An engineering, mathematical model has been developed describing radiation heat transfer and coal combustion in full scale furnaces. The model has been validated against measured temperatures and the amount of carbon in fly ash. The model...

  14. Coal combustion aerothermochemistry research. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Witte, A.B.; Gat, N.; Denison, M.R.; Cohen, L.M.

    1980-12-15

    On the basis of extensive aerothermochemistry analyses, laboratory investigations, and combustor tests, significant headway has been made toward improving the understanding of combustion phenomena and scaling of high swirl pulverized coal combustors. A special attempt has been made to address the gap between scientific data available on combustion and hardware design and scaling needs. Both experimental and theoretical investigations were conducted to improve the predictive capability of combustor scaling laws. The scaling laws derived apply to volume and wall burning of pulverized coal in a slagging high-swirl combustor. They incorporate the findings of this investigation as follows: laser pyrolysis of coal at 10/sup 6/ K/sec and 2500K; effect of coal particle shape on aerodynamic drag and combustion; effect of swirl on heat transfer; coal burnout and slag capture for 20 MW/sub T/ combustor tests for fine and coarse coals; burning particle trajectories and slag capture; particle size and aerodynamic size; volatilization extent and burnout fraction; and preheat level. As a result of this work, the following has been gained: an increased understanding of basic burning mechanisms in high-swirl combustors and an improved model for predicting combustor performance which is intended to impact hardware design and scaling in the near term.

  15. Coal combustion ashes: A radioactive Waste?

    International Nuclear Information System (INIS)

    Michetti, F.P.; Tocci, M.

    1992-01-01

    The radioactive substances naturally hold in fossil fuels, such as Uranium and Thorium, after the combustion, are subjected to an increase of concentration in the residual combustion products as flying ashes or as firebox ashes. A significant percentage of the waste should be classified as radioactive waste, while the political strategies seems to be setted to declassify it as non-radioactive waste. (Author)

  16. Combustion and environmental performance of clean coal end products

    Energy Technology Data Exchange (ETDEWEB)

    Skodras, G.; Sakellaropoulos, G. [Centre for Research and Technology, Hellas, Ptolemaidas-Kozanis, Ptolemaida (Greece). Inst. for Solid Fuel Technolgy and Applications]|[Aristotle Univ. of Thessaloniki, Thessaloniki (Greece). Dept. of Chemical Engineering, Chemical Process Engineering Lab]|[Chemical Process Engineering Research Inst., Thessaloniki (Greece). Lab. of Solid Fuels and Environment; Someus, E. [Thermal Desorption Technology Group (Greece); Grammelis, P.; Amarantos, P.S. [Centre for Research and Technology, Hellas, Ptolemaidas-Kozanis, Ptolemaida (Greece). Inst. for Solid Fuel Technolgy and Applications; Palladas, A.; Basinas, P.; Natas, P.; Prokopidou, M.; Diamantopoulou, I.; Sakellaropoulos, G. [Aristotle Univ. of Thessaloniki, Thessaloniki (Greece). Dept. of Chemical Engineering, Chemical Process Engineering Lab

    2006-07-01

    Clean and affordable power production is needed in order to achieve sustainable economic development. This paper focused on clean coal technologies in which coal-fired power plants are used in conjunction with large amounts of renewable energy sources to offer a high level of process safety and long term management of all residual operation streams. Thermal Desorption Recycle-Reduce-Reuse Technology (TDT-3R) was described as being a promising solid fuel pretreatment process for clean energy production up to 300 MWe capacities. TDT-3R is based on low temperature carbonisation fuel pre-treatment principles, which produce cleansed anthracite type fuels from coal and other carbonaceous material such as biomass and organic wastes. The combustion efficiency of such clean coals and the environmental performance of the TDT-3R process were investigated in this study via pilot scale tests of clean fuel production. Tests included flue gas emissions monitoring, raw fuel and product characterisation and thermogravimetric tests, polychlorinated dibenzo-p-dioxins and dibenzo-furans, and heavy metals analyses, and toxicity tests. Raw material included coal and biomass, such as willow, straw and demolition wood. The fuels were heated in a rotary kiln operating at 550 degrees C under slightly vacuum conditions. Clean coals were tested either alone or in conjunction with biomass fuels in a pilot scale combustion facility at Dresden, Germany. The clean coal samples were shown to have higher fixed carbon and ash content and lower volatiles compared to the respective raw coal samples. The major advantage of the TDT-3R process is the production of fuels with much lower pollutants content. Low nitrogen, sulphur, chlorine and heavy metal contents result in produced fuels that have excellent environmental performance, allow boiler operation in higher temperatures and overall better efficiency. Moreover, the use of clean fuels reduces deposition problems in the combustion chamber due to the

  17. 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

    For more than two decades, Alstom Power Inc. (Alstom) has developed a range of low cost, infurnace technologies for NOx emissions control for the domestic U.S. pulverized coal fired boiler market. This includes Alstom's internally developed TFS 2000{trademark} firing system, and various enhancements to it developed in concert with the U.S. Department of Energy. As of the date of this report, more than 270 units representing approximately 80,000 MWe of domestic coal fired capacity have been retrofit with Alstom low NOx technology. Best of class emissions range from 0.18 lb/MMBtu for bituminous coal to 0.10 lb/MMBtu for subbituminous coal, with typical levels at 0.24 lb/MMBtu and 0.13 lb/MMBtu, respectively. Despite these gains, NOx emissions limits in the U.S. continue to ratchet down for new and existing boiler equipment. On March 10, 2005, the Environmental Protection Agency (EPA) announced the Clean Air Interstate Rule (CAIR). CAIR requires 25 Eastern states to reduce NOx emissions from the power generation sector by 1.7 million tons in 2009 and 2.0 million tons by 2015. Low cost solutions to meet such regulations, and in particular those that can avoid the need for a costly selective catalytic reduction system (SCR), provide a strong incentive to continue to improve low NOx firing system technology to meet current and anticipated NOx control regulations. The overall objective of the work is to develop an enhanced combustion, low NOx pulverized coal burner, which, when integrated with Alstom's state-of-the-art, globally air staged low NOx firing systems will provide a means to achieve: Less than 0.15 lb/MMBtu NOx emissions when firing a high volatile Eastern or Western bituminous coal, Less than 0.10 lb/MMBtu NOx emissions when firing a subbituminous coal, NOx reduction costs at least 25% lower than the costs of an SCR, Validation of the NOx control technology developed through large (15 MWt) pilot scale demonstration, and Documentation required for

  18. Environmental care in coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Kvaerner Power will supply a CYMIC{reg_sign} circulating fluidized bed (CFB) boiler with a 63 MW electricity capacity to Manitowoc Public Utilities, in Manitowoc, Wisconsin, USA in 2006. This boiler is designed to burn bituminous coal and petroleum coke, with minimised emissions of SO{sub 2} and NOx. Kvaerner Power CFBs are capable of burning either coal or biomass (eg paper pellets) in any combination. Recent deliveries, to Indonesia and China as well as the USA, are listed. 1 tab., 5 photos.

  19. Predicting the combustion kinetics of Chinese coals

    Energy Technology Data Exchange (ETDEWEB)

    Niksa, Stephen [Niksa Energy Associates LLC, Belmont, CA (United States); Fujiwara, Naoki [Idemitsu Kosan Co., Ltd, Chiba (Japan). Coal and Environment Research Lab.

    2013-07-01

    The database on the devolatilization of Chinese coals in the English literature represents coals from all ranks and the major Chinese mines. It was mostly acquired with TGAs. There are sufficient datasets from devices that imposed rapid heating rates to bracket combustor behavior. The domains of heating rate, temperature, pressure, and particle size are either directly relevant to combustion conditions, or close enough to manage with modest extrapolations. Whereas the data on ultimate total yields is sufficient to validate a model for any coal type, more detailed product distributions and char compositions would be desirable. Based on the accurate interpretation of this database, there are few unresolved issues surrounding the applicability of FLASHCHAIN {sup registered} for combustion applications in China. The sub-database on devolatilization under rapid heating conditions represents 34 samples. The predicted yields were within the measurement uncertainties of 4 daf wt. % for 29 of these coals. Among the five ultimate yields that were not accurately predicted, three had measured values less than the proximate volatile matter (PVM), despite the rapid heating rates in the tests. Similarly, the sub-database on devolatilization under slow heating conditions characterizes ultimate devolatilization yields of 30 samples. The predicted yields were within the measurement uncertainties for 22 of these coals. Among the eight that were not accurately predicted, three had measured values that were much lower than the PVM (which is a problem even after accounting for the slow heating rates in the tests) and three were in studies that did not report ultimate analyses for the coals tested. Unfortunately, the database on the combustion behavior of the chars from Chinese coals is insufficient to specify char oxidation kinetics.

  20. A new power station with clean combustion of coal residues financed by the Commission wins an international prize. Una nueva central electrica de combustion limpia de residuos de carbon financiada por la Comision gana un premio internacional

    Energy Technology Data Exchange (ETDEWEB)

    Furfari, S. (Commission of the European Communities, Brussels (Belgium). Directorate General for Energy, Energy Technology Unit)

    1993-07-01

    Between 1987 and 1989 10,55 million ecus were given by the European Commission's Demonstration Programme for the construction of the Emile Huchet power station using circulating fluidized bed combustion technology. The power station was constructed jointly by Charbonnages de France, COREAL, Stein Industrie and Lurgi. An important feature was its ability to burn coal preparation wastes cleanly. Despite burning poor quality fuel its emissions are well below the maximum standards. Other stations of this type are now planned in France.

  1. Modification of combustion behaviour and NO emissions by coal blending

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, Fernando; Arenillas, Ana; Arias, Borja; Pis, Jose J. [Department of Energy and Environment, Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

    2002-06-20

    Combustion profiles determined by TGA and experiments in a laminar entrained flow reactor (EFR) were used in this work to assess the relative combustion reactivities of different rank coals and their binary coal blends. The combustion behaviour of coal blends in TGA was greatly influenced by coal rank and the proportion of each component in the blend. Higher volatile coals exerted more influence in the low-temperature region and less reactive coals in the char combustion zone. The results in the EFR indicated that coal blends burnout and NO emissions show additivity in the case of similar nature coals. When one of the components was a high-rank coal, the burnout of the blend exhibited, in some cases, positive synergistic effects, while a clear deviation from linearity was found in NO emissions.

  2. Slagging behavior of upgraded brown coal and bituminous coal in 145 MW practical coal combustion boiler

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Katsuya; Pak, Haeyang; Takubo, Yoji [Kobe Steel, Ltd, Kobe (Japan). Mechanical Engineering Research Lab.; Tada, Toshiya [Kobe Steel, Ltd, Takasago (Japan). Coal and Energy Technology Dept.; Ueki, Yasuaki [Nagoya Univ. (Japan). Energy Science Div.; Yoshiie, Ryo; Naruse, Ichiro [Nagoya Univ. (Japan). Dept. of Mechanical Science and Engineering

    2013-07-01

    The purpose of this study is to quantitatively evaluate behaviors of ash deposition during combustion of Upgraded Brown Coal (UBC) and bituminous coal in a 145 MW practical coal combustion boiler. A blended coal consisting 20 wt% of the UBC and 80 wt% of the bituminous coal was burned for the combustion tests. Before the actual ash deposition tests, the molten slag fractions of ash calculated by chemical equilibrium calculations under the combustion condition was adopted as one of the indices to estimate the tendency of ash deposition. The calculation results showed that the molten slag fraction for UBC ash reached approximately 90% at 1,523 K. However, that for the blended coal ash became about 50%. These calculation results mean that blending the UBC with a bituminous coal played a role in decreasing the molten slag fraction. Next, the ash deposition tests were conducted, using a practical pulverized coal combustion boiler. A water-cooled stainless-steel tube was inserted in locations at 1,523 K in the boiler to measure the amount of ash deposits. The results showed that the mass of deposited ash for the blended coal increased and shape of the deposited ash particles on the tube became large and spherical. This is because the molten slag fraction in ash for the blended coal at 1,523 K increased and the surface of deposited ash became sticky. However, the mass of the deposited ash for the blended coal did not greatly increase and no slagging problems occurred for 8 days of boiler operation under the present blending conditions. Therefore, appropriate blending of the UBC with a bituminous coal enables the UBC to be used with a low ash melting point without any ash deposition problems in a practical boiler.

  3. Balance of natural radionuclides in the brown coal based power generation and harmlessness of the residues and side product utilization

    International Nuclear Information System (INIS)

    Schulz, Hartmut; Kunze, Christian; Hummrich, Holger

    2017-01-01

    During brown coal combustion a partial enrichment of natural radionuclides occurs in different residues. Residues and side product from brown coal based power generation are used in different ways, for example filter ashes and gypsum from flue gas desulfurization facilities are used in the construction materials fabrication and slags for road construction. Detailed measurement and accounting of radionuclides in the mass throughputs in coal combustion power plants have shown that the utilized gypsum and filter ashes are harmless in radiologic aspects.

  4. Comparative Study of Coal and Biomass Co-Combustion With Coal Burning Separately Through Emissions Analysis

    OpenAIRE

    Mohammad Siddique; Suhail Ahmed Soomro; Aziza Aftab; Zahid Naeem Qaisrani; Abdul Sattar Jatoi; Asadullah; Ghulamullah Khan; Ehsanullah Kakar

    2016-01-01

    Appropriate eco-friendly methods to mitigate the problem of emissions from combustion of fossil fuel are highly demanded. The current study was focused on the effect of using coal & coal-biomass co-combustion on the gaseous emissions. Different biomass' were used along with coal. The coal used was lignite coal and the biomass' were tree waste, cow dung and banana tree leaves. Various ratios of coal and biomass were used to investigate the combustion behavior of coal-biomass blends and their ...

  5. Indoor Emissions from the Household Combustion of Coal

    Science.gov (United States)

    Learn about the lung cancer risk associated with burning coal inside your home. Indoor emissions from the household combustion of coal contain harmful chemicals such as benzene, carbon monoxide, and formaldehyde.

  6. Coal combustion products: trash or treasure?

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, T.

    2006-07-15

    Coal combustion by-products can be a valuable resource to various industries. The American Coal Ash Association (ACAA) collects data on production and uses of coal combustion products (CCPs). 122.5 million tons of CCPs were produced in 2004. The article discusses the results of the ACCA's 2004 survey. Fly ash is predominantly used as a substitute for Portland cement; bottom ash for structural fill, embankments and paved road cases. Synthetic gypsum from the FGD process is commonly used in wallboard. Plant owners are only likely to have a buyer for a portion of their CCPs. Although sale of hot water (from Antelope Valley Station) from condensers for use in a fish farm to raise tilapia proved unviable, the Great Plains Synfuels Plant which manufactures natural gas from lignite produces a wide range of products including anhydrous ammonia, phenol, krypton, carbon dioxide (for enhanced oil recovery), tar oils and liquid nitrogen. ACCA's goal is to educate people about CCPs and how to make them into useful products, and market them, in order to reduce waste disposal and enhance revenue. The article lists members of the ACCA. 2 photos., 1 tab.

  7. SELECTION OF SUSTAINABLE TECHNOLOGIES FOR COMBUSTION OF BOSNIAN COALS

    Directory of Open Access Journals (Sweden)

    Anes Kazagić

    2010-01-01

    Full Text Available This paper deals with optimization of coal combustion conditions to support selection a sustainable combustion technology and an optimal furnace and boiler design. A methodology for optimization of coal combustion conditions is proposed and demonstrated on the example of Bosnian coals. The properties of Bosnian coals vary widely from one coal basin to the next, even between coal mines within the same basin. Very high percentage of ash (particularly in Bosnian brown coal makes clear certain differences between Bosnian coal types and other world coal types, providing a strong argument for investigating specific problems related to the combustion of Bosnian coals, as well as ways to improve their combustion behaviour. In this work, options of the referent energy system (boiler with different process temperatures, corresponding to the different combustion technologies; pulverised fuel combustion (slag tap or dry bottom furnace and fluidized bed combustion, are under consideration for the coals tested. Sustainability assessment, based on calculation economic and environment indicators, in combination with common low cost planning method, is used for the optimization. The total costs in the lifetime are presented by General index of total costs, calculated on the base of agglomeration of basic economic indicators and the economic indicators derived from environmental indicators. So, proposed methodology is based on identification of those combustion technologies and combustion conditions for coals tested for which the total costs in lifetime of the system under consideration are lowest, provided that all environmental issues of the energy system is fulfilled during the lifetime. Inputs for calculation of the sustainability indicators are provided by the measurements on an experimental furnace with possibility of infinite variation of process temperature, supported by good praxis from the power plants which use the fuels tested and by thermal

  8. A study on the combustion behaviour of coal blends

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Fuente, E.; Arenillas, A.; Pis, J.J. [Instituto Nacional del Carbon, Oviedo (Spain)

    1999-07-01

    Combustion behaviour of four coals of varying rank and their binary blends was studied using temperature programmed combustion tests, and thermogravimetric analysis. Characteristic parameters could not be predicted from the weight percentage of individual coals in the blend. 6 refs., 4 figs., 1 tab.

  9. Oxy-Fuel Combustion of Coal

    DEFF Research Database (Denmark)

    Brix, Jacob

    This Ph.D. thesis describes an experimental and modeling investigation of the thermal conversion of coal and an experimental investigation of the emission of NO from char combustion in O2/N2 and O2/CO2 atmospheres. The motivation for the work has been the prospective use of the technology “Oxy......-Fuel Combustion” as a mean of CO2 abatement in large scale energy conversion. Entrained Flow Reactor (EFR) experiments have been conducted in O2/N2 and O2/CO2 mixtures in the temperature interval 1173 K – 1673 K using inlet O2 concentrations between 5 – 28 vol. %. Bituminous coal has been used as fuel in all....... % it was found that char conversion rate was lowered in O2/CO2 compared to O2/N2. This is caused by the lower diffusion coefficient of O2 in CO2 (~ 22 %) that limits the reaction rate in zone III compared to combustion in O2/N2. Using char sampled in the EFR experiments ThermoGravimetric Analyzer (TGA...

  10. Identification and quantification of priority species from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.; Zheng, L.; Hlavacek, T. [Canada Centre for Mineral and Energy Technology, Ottawa, ON (Canada). Energy Research Laboratories

    1996-07-01

    The objective is to quantify and characterize emissions from pulverized coal combustion of seven coals and the circulating fluidized bed combustion of four coals. The species of particular interest are sulphur, nitrogen, chlorine, arsenic, mercury, lead, cadmium, potassium, and sodium. The Facility for Analysis of Chemical Thermodynamics (F{asterisk}A{asterisk}C{asterisk}T) method is used to predict type and amount of priority species. Prediction is made for combustion with and without the presence of limestone. The results show that the combustion technology used influences the amount of priority species emitted. 16 tabs., 3 apps.

  11. Coal Combustion Wastes Reuse in Low Energy Artificial Aggregates Manufacturing

    Science.gov (United States)

    Ferone, Claudio; Colangelo, Francesco; Messina, Francesco; Iucolano, Fabio; Liguori, Barbara; Cioffi, Raffaele

    2013-01-01

    Sustainable building material design relies mostly on energy saving processes, decrease of raw materials consumption, and increase of waste and by-products recycling. Natural and lightweight artificial aggregates production implies relevant environmental impact. This paper addresses both the issues of residues recycling and energy optimization. Particularly, three coal combustion wastes (Weathered Fly Ash, WFA; Wastewater Treatment Sludge, WTS; Desulfurization Device Sludge, DDS) supplied by the Italian electric utility company (ENEL) have been employed in the manufacture of cold bonded artificial aggregates. Previously, the residues have been characterized in terms of chemical and mineralogical compositions, water content, particle size distribution, and heavy metal release behavior. These wastes have been used in the mix design of binding systems with the only addition of lime. Finally, the artificial aggregates have been submitted to physical, mechanical, and leaching testing, revealing that they are potentially suitable for many civil engineering applications. PMID:28788372

  12. Coal Combustion Wastes Reuse in Low Energy Artificial Aggregates Manufacturing.

    Science.gov (United States)

    Ferone, Claudio; Colangelo, Francesco; Messina, Francesco; Iucolano, Fabio; Liguori, Barbara; Cioffi, Raffaele

    2013-10-31

    Sustainable building material design relies mostly on energy saving processes, decrease of raw materials consumption, and increase of waste and by-products recycling. Natural and lightweight artificial aggregates production implies relevant environmental impact. This paper addresses both the issues of residues recycling and energy optimization. Particularly, three coal combustion wastes (Weathered Fly Ash, WFA; Wastewater Treatment Sludge, WTS; Desulfurization Device Sludge, DDS) supplied by the Italian electric utility company (ENEL) have been employed in the manufacture of cold bonded artificial aggregates. Previously, the residues have been characterized in terms of chemical and mineralogical compositions, water content, particle size distribution, and heavy metal release behavior. These wastes have been used in the mix design of binding systems with the only addition of lime. Finally, the artificial aggregates have been submitted to physical, mechanical, and leaching testing, revealing that they are potentially suitable for many civil engineering applications.

  13. Coal Combustion Wastes Reuse in Low Energy Artificial Aggregates Manufacturing

    Directory of Open Access Journals (Sweden)

    Raffaele Cioffi

    2013-10-01

    Full Text Available Sustainable building material design relies mostly on energy saving processes, decrease of raw materials consumption, and increase of waste and by-products recycling. Natural and lightweight artificial aggregates production implies relevant environmental impact. This paper addresses both the issues of residues recycling and energy optimization. Particularly, three coal combustion wastes (Weathered Fly Ash, WFA; Wastewater Treatment Sludge, WTS; Desulfurization Device Sludge, DDS supplied by the Italian electric utility company (ENEL have been employed in the manufacture of cold bonded artificial aggregates. Previously, the residues have been characterized in terms of chemical and mineralogical compositions, water content, particle size distribution, and heavy metal release behavior. These wastes have been used in the mix design of binding systems with the only addition of lime. Finally, the artificial aggregates have been submitted to physical, mechanical, and leaching testing, revealing that they are potentially suitable for many civil engineering applications.

  14. DEVELOPMENT OF A VORTEX CONTAINMENT COMBUSTOR FOR COAL COMBUSTION SYTEMS

    Science.gov (United States)

    The report describes the development of a vortex containment combustor (VCC) for coal combustion systems, designed to solve major problems facing the conversion of oil- and gas-fired boilers to coal (e.g., derating, inorganic impurities in coal, and excessive formation of NOx and...

  15. Geochemistry of coals, coal ashes and combustion wastes from coal-fired power stations

    International Nuclear Information System (INIS)

    Vassilev, S.V.; Vassileva, C.G.

    1997-01-01

    Contents, concentration trends, and modes of occurrence of 67 elements in coals, coal ashes, and combustion wastes at eleven Bulgarian thermoelectric power stations (TPS) were studied. A number of trace elements in coal and coal ash have concentrations greater than their respective worldwide average contents (Clarke values). Trace elements are concentrated mainly in the heavy accessory minerals and organic matter in coal. In decreasing order of significance, the trace elements in coal may occur as: element-organic compounds; impurities in the mineral matter; major components in the mineral matter; major and impurity components in the inorganic amorphous matter; and elements in the fluid constituent. A number of trace elements in the waste products, similar to coal ashes, exceed known Clarke contents. Trace elements are mainly enriched in non-magnetic, heavy and fine-grained fractions of fly ash. They are commonly present as impurities in the glass phases, and are included in the crystalline components. Their accessory crystalline phases, element-organic compounds, liquid and gas forms, are of subordinate importance. Some elements from the chalcophile, lithophile and siderophile groups may release into the atmosphere during coal burning. For others, the combustion process appears to be a powerful factor causing their relative enrichment in the fly ash and rarely in the bottom ash and slag. 65 refs., 1 fig., 11 tabs

  16. Large-eddy simulation of swirling pulverized-coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hu, L.Y.; Luo, Y.H. [Shanghai Jiaotong Univ. (China). School of Mechanical Engineering; Zhou, L.X.; Xu, C.S. [Tsinghua Univ., Beijing (China). Dept. of Engineering Mechanics

    2013-07-01

    A Eulerian-Lagrangian large-eddy simulation (LES) with a Smagorinsky-Lilly sub-grid scale stress model, presumed-PDF fast chemistry and EBU gas combustion models, particle devolatilization and particle combustion models are used to study the turbulence and flame structures of swirling pulverized-coal combustion. The LES statistical results are validated by the measurement results. The instantaneous LES results show that the coherent structures for pulverized coal combustion is stronger than that for swirling gas combustion. The particles are concentrated in the periphery of the coherent structures. The flame is located at the high vorticity and high particle concentration zone.

  17. The release of nitrogen in coal combustion and pyrolysis

    International Nuclear Information System (INIS)

    Varey, J.E.; Hindmarsh, C.J.; Thomas, K.M.

    1994-01-01

    Environmental aspects of coal utilization are a major concern. Recent advances in the development of low NO x burners and the emerging technologies of fluidized bed combustion have led to the identification of coal char nitrogen as the major contributor to the nitrogen oxides released during combustion. The temperature programmed combustion and pyrolysis of a series of coals covering a wide range of rank have been investigated. In addition, maceral concentrates have been investigated to assess the variation in the combustion behavior and the release of nitrogen in the pyrolysis and combustion of macerals. This investigation has involved the use of thermogravimetric analysis - mass spectrometry (TG-MS) with two sampling options: (1) ∼1cm from the sample and (2) at the exit of the TG. The former allows reactive species to be identified in the combustion of the coals. These temperature programmed combustion results have been compared with similar measurements carried out at the exit of the TG where the products are at equilibrium. In addition, pyrolysis studies have been carried out under similar conditions. The results show that reactive intermediate species such as HCN, (CN) 2 , COS etc. can be detected in the combustion products. The evolution of these species during combustion are compared with the pyrolysis products of the coal. The results are discussed in relation to the structure of the coals and the conversion of volatile species and char nitrogen to nitrogen oxides

  18. Combustion behaviour of ultra clean coal obtained by chemical demineralisation

    Energy Technology Data Exchange (ETDEWEB)

    F. Rubiera; A. Arenillas; B. Arias; J.J. Pis; I. Suarez-Ruiz; K.M. Steel; J.W. Patrick [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2003-10-01

    The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new coal cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from coal either by physical or chemical methods can be annulled if poor coal combustibility characteristics are attained. In this work a high volatile bituminous coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the clean coal was reduced to 0.3%. The original and treated coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system. Comparison of the combustion behaviour and pollutant emissions of both coals was conducted in a drop tube furnace operating at 1000{sup o}C. The results of this work indicate that the char obtained from the chemically treated coal presents very different structure, morphology and reactivity behaviour than the char from the original coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised coal.

  19. Burnout synergic or inhibiting effects in combustion assays of coal/sawdust blends

    Energy Technology Data Exchange (ETDEWEB)

    Ximena Garcia; Ximena Matus; Claudia Ulloa; Alfredo L. Gordon [University of Concepcion, Concepcion (Chile). Dept. of Chemical Engineering

    2007-07-01

    Characterization of chars and charcoal and combustion assays of coal/ pine sawdust blends were carried on to evaluate the burnout, under conditions similar to those found in pulverized coal combustion. A drop tube furnace (DTF) was used to generate chars from three coals of different rank (Bitsch, a lignite; Lemington, a bituminous HV coal; and LD, a semianthracite) and charcoal from sawdust (S). Burning profiles, as well as morphological and optical characterization of these chars were obtained and discussed. Pulverized samples of pure constituents and sawdust/coal blends (5, 10 and 20%wt of S) were burned in the DTF reactor. Samples of combustion residues were collected for characterization. Depending on blend composition and the rank of the coal being blended, positive and negative deviations with respect to the expected weighted average value of the burnout were measured. This behavior is related both, to the duration of the step by which simultaneous burning of char and charcoal take place, and to the sawdust content in the blend. The optical analysis of combustion residues supports this conclusion. 7 refs., 6 figs., 3 tabs.

  20. Effect of the grinding behaviour of coal blends on coal utilisation for combustion

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Arenillas, A.; Fuente, E.; Pis, J.J. [Inst. Nacional del Carbon, CSIC, Oviedo (Spain); Miles, N. [School of Chemical, Environmental and Mining Engineering, Nottingham Univ. (United Kingdom)

    1999-11-01

    Grinding of a high volatile bituminous coal was performed in three comminution devices: Raymond Mill (RM), Rolls Crusher (RC) and Ball Mill (BM). The pulverised samples were sieved to obtain four particle size fractions, and temperature-programmed combustion (TPC) was used for the evaluation of their combustion behaviour. In addition, three coals of different hardness and rank were mixed in various proportions in order to compare the combustibility characteristics of the binary coal blends with those of the individual coals. The effect of coal blending on grindability was also studied. It was found that grindability was non-additive especially when coals of very different hardgrove grindability index (HGI) were blended. The combustion studies also suggested that there exists an interaction between individual coals when they are burnt as a blend. (orig.)

  1. Fluidised-bed combustion of gasification residue

    Energy Technology Data Exchange (ETDEWEB)

    Korpela, T.; Kudjoi, A.; Hippinen, I.; Heinolainen, A.; Suominen, M.; Lu Yong [Helsinki Univ. of Technology (Finland). Lab of Energy Economics and Power Plant Engineering

    1996-12-01

    Partial gasification processes have been presented as possibilities for future power production. In the processes, the solid materials removed from a gasifier (i.e. fly ash and bed material) contain unburnt fuel and the fuel conversion is increased by burning this gasification residue either in an atmospheric or a pressurised fluidised-bed. In this project, which is a part of European JOULE 2 EXTENSION research programme, the main research objectives are the behaviour of calcium and sulphur compounds in solids and the emissions of sulphur dioxide and nitrogen oxides (NO{sub x} and N{sub 2}O) in pressurised fluidised-bed combustion of gasification residues. (author)

  2. Possibility of Coal Combustion Product Conditioning

    Science.gov (United States)

    Błaszczyński, Tomasz Z.; Król, Maciej R.

    2018-03-01

    This paper is focused on properties of materials known as green binders. They can be used to produce aluminium-siliceous concrete and binders known also as geopolymers. Comparing new ecological binders to ordinary cements we can see huge possibility of reducing amount of main greenhouse gas which is emitted to atmosphere by 3 to even 10 times depending of substrate type used to new green material production. Main ecological source of new materials obtaining possibility is to use already available products which are created in coal combustion and steel smelting process. Most of them are already used in many branches of industry. They are mostly civil engineering, chemistry or agriculture. Conducted research was based on less popular in civil engineering fly ash based on lignite combustion. Materials were examine in order to verify possibility of obtaining hardened mortars based of different factors connected with process of geopolymerization, which are temperature, amount of reaction reagent and time of heat treatment. After systematizing the matrices for the basic parameters affecting the strength of the hardened mortars, the influence of the fly ash treatment for increasing the strength was tested.

  3. Application of coal combustion residues to the stabilization/solidification of industrial wastes (IRIS); Desarrollo de un Proceso, a Escala Piloto de Inertizacion de Residuos Industriales con Cenizas Volantes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    Stabilization/solidification (S/S) processes, also called inertization processes, are a group of techniques which employ additives to reduce the mobility of the hazardous components from the waste and make possible for the residue to be accepted for its disposal in a safe way. These processes, mainly applied to wastes that contain heavy metals (such as lead, zinc, cadminum, mercury, copper, nickel, titanium, chromium-III, chromium-VI, arsenic,....) change the waste into a solid-like material in which the metals are trapped (nets and matrix) by physical or chemical links. The IRIS Project, carried out by AICIA through the ECSC Coal Programme with the participation of two industrial partners (Sevillana de Electricidad and EGMASA, a public-owned company for waste treatment), has developed, at pilot scale, a new S/S process for inorganic industrial wastes that uses great quantities of fly ash in the place of other more commonly used and expansive reagents. A pilot plant for 200 kg/h has been designed, built and operated. This facility has allowed to add improvements and scientific foundations to existing S/S technology. It has also allowed to obtain industrial scale parameters for fixed and portable plants. Experiencie have been mainly carried out using fly ash from high quality coals, but types of ash have been tested coming from coals with a greater calcium content, from fluidised bed combustion boilers and from desulphurisation processes, giving very suitable characteristics for their application to S/S processes. The addition of fly ash (up to 30%) in the IRIS process improves the results in comparison with the S/S processes that use only cement, because the final pH obtained (8-11) does not allow amphoteric metallic ions to escape in the leachate. The same as other S/S processes, IRIS can be applied also to wastes that contain certain metals (chromium-VI, arsenic, for example) with specific pre-treatments (redox, for example). The efficiency of the IRIS treatment

  4. Residual coal exploitation and its impact on sustainable development of the coal industry in China

    International Nuclear Information System (INIS)

    Zhang, Yujiang; Feng, Guorui; Zhang, Min; Ren, Hongrui; Bai, Jinwen; Guo, Yuxia; Jiang, Haina; Kang, Lixun

    2016-01-01

    Although China owns large coal reserves, it now faces the problem of depletion of its coal resources in advance. The coal-based energy mix in China will not change in the short term, and a means of delaying the coal resources depletion is therefore urgently required. The residual coal was exploited first with a lower recovery percentage and was evaluated as commercially valuable damaged coal. This approach is in comparison to past evaluations when the residual coal was allocated as exploitation losses. Coal recovery rates, the calculation method of residual coal reserves and statistics of its mines in China were given. On this basis, a discussion concerning the impacts on the delay of China's coal depletion, development of coal exploitation and sustainable developments, as well as technologies and relevant policies, were presented. It is considered that the exploitation of residual coal can effectively delay China's coal depletion, inhibit the construction of new mines, redress the imbalance between supply and demand of coal in eastern China, improve the mining area environment and guarantee social stability. The Chinese government supports the exploitation technologies of residual coal. Hence, exploiting residual coal is of considerable importance in sustainable development of the coal industry in China. - Highlights: •Pay attention to residual coal under changing energy-mix environment in China. •Estimate residual coal reserves and investigate its exploitation mines. •Discuss impacts of residual coal exploitation on delay of coal depletion in China. •Discuss impacts on coal mining industry and residual coal exploitation technology. •Give corresponding policy prescriptions.

  5. NOx emissions and combustibility characteristics of coal blends

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Arenillas, A.; Arias, B.; Pis, J.J. [CSIC, Instituto Nacional del Carbon, Oviedo (Spain). Dept. of Energy and Environment

    2001-07-01

    In this work, a series of coals with different origin and rank were blended and several aspects of the resultant blends were studied. This included determination of the grindability of individual coals and blends by means of the Hardgrove Grindability Index (HGI), and temperature programmed combustion test, which were carried out in a thermogravimetric analyser (TG) coupled to a quadruple mass spectrometer (MS) for evolved gas analysis. Special attention was paid to the combustibility parameters and the NO emissions during blends combustion. It was found that while some coal blends present interaction between the individual coals, others do not. This behaviour was assumed to be due to the differences in coal structure and functional groups composition. 18 refs., 11 figs., 2 tabs.

  6. Combustion characterization of beneficiated coal-based fuels

    Energy Technology Data Exchange (ETDEWEB)

    Chow, O.K.; Levasseur, A.A.

    1995-11-01

    The Pittsburgh Energy Technology Center (PETC) of the U.S. Department of Energy is sponsoring the development of advanced coal-cleaning technologies aimed at expanding the use of the nation`s vast coal reserves in an environmentally and economically acceptable manner. Because of the lack of practical experience with deeply beneficiated coal-based fuels, PETC has contracted Combustion Engineering, Inc. to perform a multi-year project on `Combustion Characterization of Beneficiated Coal-Based Fuels.` The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of Beneficiated Coal-Based Fuels (BCs) 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.

  7. Prevention of spontaneous combustion in coal stockpiles : Experimental results in coal storage yard

    NARCIS (Netherlands)

    Fierro, V.; Miranda, J.L.; Romero, C.; Andrés, J.M.; Arriaga, A.; Schmal, D.; Visser, G.H.

    1999-01-01

    The spontaneous ignition of coal stockpiles is a serious economic and safety problem. This paper deals with oxidation and spontaneous combustion of coal piles laid in coal storage yard and the measures to avoid the heat losses produced. Investigations on self heating were carried out with five test

  8. Atmospheric emission of mercury due to combustion of steam coal and domestic coal in China

    Science.gov (United States)

    Wang, Shaobin; Luo, Kunli

    2017-08-01

    To study the mercury emission due to the combustion of steam coal and domestic coal in China, we analyzed the mercury contents of coal, fly ash, bottom ash and sluicing water in thermal power plants, steam boilers as well as domestic coal-stoves, in Shaanxi, Shanxi, Shandong and Yunnan Provinces. This study conduct an estimate of the Hg emission rates from steam coal and domestic coal combustion based on the method of mass distribution ratio of fly ash and bottom ash. The results show that the Hg emission rate of coal combustion in thermal power plants is about 50.21% (electrostatic precipitators + wet flue gas desulfurization), and that in heating boilers is about 67.23%, and 92.28% in industrial boilers without flue gas desulphurisation equipment. Furthermore, Hg emission rate is 83.61% due to domestic coal combustion in coal-stoves. The Hg emission amount into the atmosphere from power and heat generation, industrial boilers, domestic coal-stoves and spontaneous combustion of coal gangue is roughly estimated to be 133 ± 4, 100 ± 17, 11 ± 0.1 and 47 ± 26 tons in China in 2014, respectively, and the total Hg emission amount from this paper is estimated at 292 tons. The trends of Hg emission in China from 1991 to 2014 show an accelerating growth after 2002. The proportion of mercury emission due to thermal power, heating generation and industrial energy utilization continuously increased. The atmospheric emission of mercury due to combustion of steam coal, domestic coal and coal gangue accounts nearly 50% in total anthropogenic Hg emissions in China, indicating one of the largest sources of Hg emission in China which should draw more public and scientific attention in the future.

  9. Biodesulfurization of coals of different rank: Effect on combustion behavior

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Arenillas, A.; Fuente, E.; Pis, J.J. [CSIC, Oviedo (Spain). Inst. Nacional del Carbon; Marteinz, O.; Moran, A. [Univ. de Leon (Spain). Escuela de Ingenieria Tecnica Minera

    1999-02-01

    The emission of sulfur oxides during the combustion of coal is one of the causes, among other air pollution problems, of acid rain. The contribution of coal as the mainstay of power production will be determined by whether its environmental performance is equal or superior to other supply options. In this context, desulfurization of coal before combustion by biological methods was studied. Four Spanish high-sulfur content coals of different rank were inoculated with bacteria isolated from mine-drainage waters and with naturally occurring bacteria inherent in the coals to be treated. Higher levels of desulfurization were obtained in the case of the samples treated with their own accompanying bacteria and when aeration was increased. All the samples were amenable to the biodepyritization processes. However, it is of little value to achieve large sulfur reductions if a decrease in coal combustion performance is obtained in the process. For this reason, a comparison was made between the combustibility characteristics of the original coals and those of the biodesulfurized samples. Results indicated that combustibility was not substantially modified by the overall biological treatment. The benefits of reduced sulfur emissions into the atmosphere ought to be taken into account as part of the general evaluation of the processes.

  10. Emissions of organic hazardous air pollutants during Chinese coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yan, R.; Zhu, H.J.; Zheng, C.G.; Xu, M.H. [Environmental Technology Institute, Singapore (Singapore). Innovative Center

    2002-05-01

    The emissions of organic hazardous air pollutants (HAPs) during the combustion of several typical Chinese coals were investigated. First, the distribution of four types of HAP, i.e., aliphatics, cyclic hydrocarbons, monoaromatic compounds and PAHs, in the CH{sub 2}C{sub l2} extracts of six Chinese coals were studied and the influences of the extractive times and coal varieties were also evaluated. Second, the partitioning of these HAPs in the flue gas during coal combustion in a small-scale reactor were investigated, depending on oven temperatures (500, 600, 700, 800, 900{sup o}C) and coal varieties. The behaviors of HAP in the combustion flue gas were compared with those in the CH{sub 2}, Cl{sub 2}, extracts. Finally, combustion was conducted at given conditions in two laboratory-scale reactors: a fluidized bed and a fixed bed. Two coals (Shengmu bituminous coal and Xunhuan anthracite coal) and one coke were considered. The HAP partitioning both in flue gases and in ashes were evaluated and compared between the two combustors.

  11. The rheodynamics and combustion of coal-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Burdukov, A.P.; Popov, V.I.; Tomilov, V.G.; Fedosenko, V.D. [Russian Academy of Science, Novosibirsk (Russian Federation). Inst. of Thermophysics (Siberian Branch, Russian Academy of Science)

    2002-05-01

    Investigation methods for characteristics of movement along the tubes, combustion dynamics and gasification of separate drops were developed for the coal-water mixtures (CWM). The following parameters were determined on the basis of laser heating: thermometric, pyrometric and concentration dynamics of single-drop combustion, complete combustion times, duration of temperature phases of combustion, as well as the moment and temperature of ignition. Information on the combustion mass velocity and gasification products was also obtained using laser heating. 6 refs., 13 figs., 1 tab.

  12. Gradual combustion - method for nitrogen oxide suppression during brown coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.P.; Verzakov, V.N.; Lobov, T.V.

    1990-10-01

    Discusses combustion of brown coal in BKZ-500-140-1 boilers and factors that influence emission of nitrogen oxides. Temperature distribution in the furnace was evaluated. Effects of burner position, burner number and burner type as well as air excess ratio on chemical reactions during brown coal combustion, formation of nitrogen oxides and their emission were comparatively evaluated. Analyses showed that by optimum arrangement of burners and selecting the optimum air excess ratio a part of nitrogen oxides formed during the initial phase of combustion was reduced to molecular nitrogen in the second phase. On the basis of evaluations the following recommendations for furnace design are made: use of straight-flow burners characterized by a reduced mixing ratio with secondary air, parallel arrangement of burners which guarantees mixing of the combustion products from the burners with stable and unstable combustion (products of incomplete coal combustion), reducing the air excess ratio to below 1.0. 5 refs.

  13. Electricity generation from solid biomass via co-combustion with coal. Energy and emission balances from a German case study

    International Nuclear Information System (INIS)

    Hartmann, D.; Kaltschmitt, M.

    1999-01-01

    The environmental effects of electricity production from different biofuels by means of co-combustion with hard coal in existing coal fired power plants are analysed and compared to electricity production from hard coal alone based on Life Cycle Analysis (LCA). The use of straw and residual wood at a 10% blend with coal in an existing power plant in the southern part of Germany shows that all investigated environmental effects are significantly lower if biomass is used instead of coal. Thus based on the available and proven technology of co-combustion of hard coal and biomass in existing power plants a significant contribution could be made to a more environmentally sound energy system compared to using coal alone. (author)

  14. Atmospheric fluidized bed coal combustion research, development and application

    CERN Document Server

    Valk, M

    1994-01-01

    The use of fluidized bed coal combustion technology has been developed in the past decade in The Netherlands with a view to expanding the industrial use of coal as an energy supply. Various research groups from universities, institutes for applied science and from boiler industries participated and contributed to this research area. Comprehensive results of such recent experimentation and development work on atmospheric fluidized bed combustion of coal are covered in this volume. Each chapter, written by an expert, treats one specific subject and gives both the theoretical background as well a

  15. LES and RANS modeling of pulverized coal combustion in swirl burner for air and oxy-combustion technologies

    International Nuclear Information System (INIS)

    Warzecha, Piotr; Boguslawski, Andrzej

    2014-01-01

    Combustion of pulverized coal in oxy-combustion technology is one of the effective ways to reduce the emission of greenhouse gases into the atmosphere. The process of transition from conventional combustion in air to the oxy-combustion technology, however, requires a thorough investigations of the phenomena occurring during the combustion process, that can be greatly supported by numerical modeling. The paper presents the results of numerical simulations of pulverized coal combustion process in swirl burner using RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) methods for turbulent flow. Numerical simulations have been performed for the oxyfuel test facility located at the Institute of Heat and Mass Transfer at RWTH Aachen University. Detailed analysis of the flow field inside the combustion chamber for cold flow and for the flow with combustion using different numerical methods for turbulent flows have been done. Comparison of the air and oxy-coal combustion process for pulverized coal shows significant differences in temperature, especially close to the burner exit. Additionally the influence of the combustion model on the results has been shown for oxy-combustion test case. - Highlights: • Oxy-coal combustion has been modeled for test facility operating at low oxygen ratio. • Coal combustion process has been modeled with simplified combustion models. • Comparison of oxy and air combustion process of pulverized coal has been done. • RANS (Reynolds-averaged Navier–Stokes equations) and LES (large Eddy simulation) results for pulverized coal combustion process have been compared

  16. Experimental evaluation of main emissions during coal processing waste combustion.

    Science.gov (United States)

    Dmitrienko, Margarita A; Legros, Jean C; Strizhak, Pavel A

    2018-02-01

    The total volume of the coal processing wastes (filter cakes) produced by Russia, China, and India is as high as dozens of millions of tons per year. The concentrations of CO and CO 2 in the emissions from the combustion of filter cakes have been measured directly for the first time. They are the biggest volume of coal processing wastes. There have been many discussions about using these wastes as primary or secondary components of coal-water slurries (CWS) and coal-water slurries containing petrochemicals (CWSP). Boilers have already been operationally tested in Russia for the combustion of CWSP based on filter cakes. In this work, the concentrations of hazardous emissions have been measured at temperatures ranging from 500 to 1000°С. The produced CO and CO 2 concentrations are shown to be practically constant at high temperatures (over 900°С) for all the coal processing wastes under study. Experiments have shown the feasibility to lowering the combustion temperatures of coal processing wastes down to 750-850°С. This provides sustainable combustion and reduces the CO and CO 2 emissions 1.2-1.7 times. These relatively low temperatures ensure satisfactory environmental and energy performance of combustion. Using CWS and CWSP instead of conventional solid fuels significantly reduces NO x and SO x emissions but leaves CO and CO 2 emissions practically at the same level as coal powder combustion. Therefore, the environmentally friendly future (in terms of all the main atmospheric emissions: CO, CO 2 , NO x , and SO x ) of both CWS and CWSP technologies relies on low-temperature combustion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Washability characteristics of residual coals obtained from solvent extraction: studies towards developing cleaner coal technology

    Energy Technology Data Exchange (ETDEWEB)

    Giri, C.C.; Sharma, D.K. [Indian Institute of Technology, New Delhi (India). Centre for Energy Studies

    2004-07-01

    The washability characteristics of original Indian coals and solvent-extracted residual coals were studied by the float and sink technique. The following conclusions were drawn on the basis of the present study. Anthracene oil-extracted residual coals have lower percentage of reactions in the specific gravity range of 1.4 to 1.6 than the original coals, which indicates that the mineral matter is disassociated from the organic mass, and the anthracene oil-extracted residual coal is more suitable for washing than the original coal. The floatability behaviour of coal increases during NMP (N-methyl-2-pyrrolidone) extraction. This indicates that coal changes its washability character during NMP extractions. As during NMP extraction the surface area of coal increases by creating fissures in the matrix, the chemical leaching technique would be more suitable to remove the mineral matter in the residual coals. 12 refs., 3 figs., 2 tabs.

  18. Numerical simulation of altitude impact on pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Xiaohui; He, Boshu; Ling, Ling; Wang, Lei [Beijing Jiaotong Univ., Beijing (China). Inst. of Mechanical, Electronic and Control Engineering

    2013-07-01

    A drop-tube Furnace simulation model has been developed to investigate the pulverized coal combustion characteristics under different altitudes using the commercially available software Fluent. The altitude conditions of 0, 500, 1,000, 1,500 m have been discussed. The results included the fields of temperature, pressure, velocity, the coal burnout, CO burnout and NO emission in the tube furnace. The variation of these parameters with altitude has been analyzed. The coal combustion characteristics were affected by the altitude. The time and space for coal burnout should be increased with the rise of altitude. The valuable results could be referenced in the design of coal- fired furnaces for the high altitude areas.

  19. Investigation on the transient enthalpy of coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Pei-fang; Wang, Na; Yu, Bo; Zhang, Bin; Liu, Yang; Zhou, Huai-chun [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion

    2013-07-01

    The transient enthalpy ({Delta}h) of coal/char combustion of the three different coals (including anthracite, bituminous, and lignite) during the process of combustion is determined as a function of burn-off degree by using thermo-gravimetric-differential scanning calorimeter (TG-DSC) simultaneous thermal analyzer, and The error of determining calorific values of coals/chars is less 5% compared the results of TG-DSC with that of an automatic isoperibol calorimeter. It is found that In the initial stage, all the {Delta}h of coals are greater than that of the char pyrolysized from parent coal for many of volatiles contained more a great deal of heat per unit mass oxidized at low temperature, it also imply that coal is more easily ignited than char corresponded; And in the middle stage, all the {Delta}h of coals is lower than that of the char pyrolysized, so the pyrolysized char oxidation can supply much more of thermo-energy per unit mass. {Delta}h are almost a constant when the burn-off degree is equal to between 0.35/0.15 and 0.95/0.85 for ZCY bituminous coal/char and JWY anthracite/char, between 0.35/0.35 and 0.75/0.9 for SLH lignite/char; In the later stage, the {Delta}h of the coal/char decreased with the burn-off degree, it imply that the activity of the coal/char decreases. Therefore, coal pyrolysis changes not only the structure of char, but also the property of release heat; the transient enthalpy of coal/char combustion has been in change with the burn-out degree.

  20. Comparative study of coal and biomass co-combustion with coal burning separately through emissions analysis

    International Nuclear Information System (INIS)

    Siddique, M.; Asadullah, A.; Khan, G.; Soomro, S.A.

    2016-01-01

    Appropriate eco-friendly methos to mitigate the problem of emissions from combustion of fossil fuel are highly demanded. The current study was focused on the effect of using coal and coal biomass co-combustion on the gaseous emissions. Different biomass were used along with coal. The coal used was lignite coal and the biomass' were tree waste, cow dung and banana tree leaves Various ratios of coal and biomass were used to investigate the combustion behavior of coal cow dung and 100% banana tree leaves emits less emission of CO, CO/sub 2/, NOx and SO/sub 2/ as compared to 100% coal, Maximum amount of CO emission were 1510.5 ppm for bannana tree waste and minimum amount obtained for lakhra coal and cow dung manure (70:30) of 684.667 leaves (90:10) and minimum amount of SO/sub 2/ present in samples is in lakhra coal-banana tree waste (80:20). The maximum amount of NO obtained for banana tree waste were 68 ppm whereas amount from cow dung manure (30.83 ppm). The study concludes that utilization of biomass with coal could make remedial action against environment pollution. (author)

  1. Thermal Behavior of Coal Used in Rotary Kiln and Its Combustion Intensification

    Directory of Open Access Journals (Sweden)

    Qiang Zhong

    2018-04-01

    Full Text Available Pyrolysis and combustion behaviors of three coals (A, B, and C coals were investigated and their combustion kinetics were calculated by the Freeman–Carroll method to obtain quantitative insight into their combustion behaviors. Moreover, the effects of coal size, air flow, oxygen content, and heating rate on coal combustion behaviors were analyzed. Results showed that the three coals have a similar trend of pyrolysis that occurs at about 670 K and this process continuously proceeds along with their combustion. Combustion characteristics and kinetic parameters can be applied to analyze coal combustion behaviors. Three coals having combustion characteristics of suitable ignition temperature (745–761 K, DTGmax (14.20–15.72%/min, and burnout time (7.45–8.10 min were analyzed in a rotary kiln. Combustion kinetic parameters provide quantitative insights into coal combustion behavior. The suitable particle size for coal combustion in a kiln is that the content of less than 74 μm is 60% to 80%. Low activation energy and reaction order make coal, especially C coal, have a simple combustion mechanism, great reactivity, be easily ignited, and a low peak temperature in the combustion state. Oxygen-enrichment and high heating rates enhance coal combustion, increasing combustion intensity and peak value, thus shortening burnout time.

  2. Mercury in coal and the impact of coal quality on mercury emissions from combustion systems

    International Nuclear Information System (INIS)

    Kolker, Allan; Senior, Constance L.; Quick, Jeffrey C.

    2006-01-01

    The proportion of Hg in coal feedstock that is emitted by stack gases of utility power stations is a complex function of coal chemistry and properties, combustion conditions, and the positioning and type of air pollution control devices employed. Mercury in bituminous coal is found primarily within Fe-sulfides, whereas lower rank coal tends to have a greater proportion of organic-bound Hg. Preparation of bituminous coal to reduce S generally reduces input Hg relative to in-ground concentrations, but the amount of this reduction varies according to the fraction of Hg in sulfides and the efficiency of sulfide removal. The mode of occurrence of Hg in coal does not directly affect the speciation of Hg in the combustion flue gas. However, other constituents in the coal, notably Cl and S, and the combustion characteristics of the coal, influence the species of Hg that are formed in the flue gas and enter air pollution control devices. The formation of gaseous oxidized Hg or particulate-bound Hg occurs post-combustion; these forms of Hg can be in part captured in the air pollution control devices that exist on coal-fired boilers, without modification. For a given coal type, the capture efficiency of Hg by pollution control systems varies according to type of device and the conditions of its deployment. For bituminous coal, on average, more than 60% of Hg in flue gas is captured by fabric filter (FF) and flue-gas desulfurization (FGD) systems. Key variables affecting performance for Hg control include Cl and S content of the coal, the positioning (hot side vs. cold side) of the system, and the amount of unburned C in coal ash. Knowledge of coal quality parameters and their effect on the performance of air pollution control devices allows optimization of Hg capture co-benefit

  3. Toxic substances from coal combustion -- A comprehensive assessment

    Energy Technology Data Exchange (ETDEWEB)

    Senior, C.L.; Huggins, F.E.; Huffman, G.P.; Shan, N.; Yap, N.; Wendt, J.O.L.; Seames, W.; Ames, M.R.; Sarofim, A.F.; Swenson, S.; Lighty, J.; Kolker, A.; Finkelman, R.; Palmer, C.; Mroczkowski, S.; Helble, J.; Mamani-Paco, R.; Sterling, R.; Dunham, G.; Miller, S.

    2000-08-17

    The final program review meeting of Phase II was held on June 22 in Salt Lake City. The goals of the meeting were to present work in progress and to identify the remaining critical experiments or analyses, particularly those involving collaboration among various groups. The information presented at the meeting is summarized in this report. Remaining fixed bed, bench-scale experiments at EERC were discussed. There are more ash samples which can be run. Of particular interest are high carbon ash samples to be generated by the University of Arizona this summer and some ash-derived sorbents that EERC has evaluated on a different program. The use of separation techniques (electrostatic or magnetic) was also discussed as a way to understand the active components in the ash with respect to mercury. XAFS analysis of leached and unleached ash samples from the University of Arizona was given a high priority. In order to better understand the fixed bed test results, CCSEM and Moessbauer analyses of those ash samples need to be completed. Utah plans to analyze the ash from the single particle combustion experiments for those major elements not measured by INAA. USGS must still complete mercury analyses on the whole coals and leaching residues. Priorities for further work at the SHRIMP-RG facility include arsenic on ash surfaces and mercury in sulfide minerals. Moessbauer analyses of coal samples from the University of Utah were completed; samples from the top and bottom layers of containers of five different coals showed little oxidation of pyrite in the top relative to the bottom except for Wyodak.

  4. NOx emissions from the underfeed combustion of coal and biomass

    International Nuclear Information System (INIS)

    Purvis, M.R.I.; Tadulan, E.L.; Tariq, A.S.

    2000-01-01

    Underfeed stokers have an inherent ability to minimise smoke emissions, thus providing environmental benefits in the combustion of solid fuels, such as biomass materials, which have a high volatile matter content. An evaluation of this attribute requires comparisons of the performance of combustion equipment using these fuels against reference data for coals. However, the recent literature is virtually devoid of studies of coal combustion in underfeed stokers and, in particular, information on nitrogen oxide emissions. In the UK, this reflects a lack of commercial interest in small-scale coal firing due to the wide availability of inexpensive gas and oil fuels. An experimental investigation has been carried out into the combustion of bituminous coal, anthracite and a 50:50 blend by mass of anthracite and oak wood chips on a modified commercial underfeed stoker. The intention was to obtain operational experiences in burning the fuels and reference data for nitrogen oxide emissions. Problems in the combustion of the fuels are described and related to the determination of nitrogen oxide emission values found under optimised plant conditions. These values, expressed at 6% O 2 , were 265 ppm for bituminous coal, 90 ppm for anthracite and 106 ppm for the anthracite/wood chip blend. (Author)

  5. Modelling of NO formation in the combustion of coal blends

    Energy Technology Data Exchange (ETDEWEB)

    Arenillas, A.; Backreedy, R.I.; Jones, J.M.; Pis, J.J.; Pourkashanian, M.; Rubiera, F.; Williams, A. [CSIC, Instituto Nacional del Carbon, Oviedo (Spain)

    2002-03-01

    Coal blending is becoming of increasing importance in power stations firing pulverised coal as a result of increasing competition, stricter emission legislation and is an attractive way of improving plant economic and combustion performance. Presently, the two general methods used by power station operators to assess or predict the performance of an unknown coal blend to be fired in power station boilers are by the use of experimental large scale rig tests or correlation indices derived from experience of firing other coal blends in the power station environment. The first is expensive and the second is of doubtful accuracy in some cases. This paper evaluates the application of mathematical modelling of the combustion of a series of binary coal blends in the test situation of a drop tube reactor to predict the NO emissions and degree of char burnout. Its applicability to low NOx burners used in power stations is discussed and it is concluded that present mathematical coal combustion models are not developed sufficiently to enable an adequate description of the binary blends and the physical and chemical processes, which may include interactions, during combustion of the blend. This means that accurate predictions cannot be made. 20 refs., 4 figs., 5 tabs.

  6. Automated cost modeling for coal combustion systems

    International Nuclear Information System (INIS)

    Rowe, R.M.; Anast, K.R.

    1991-01-01

    This paper reports on cost information developed at AMAX R and D Center for coal-water slurry production implemented in an automated spreadsheet (Lotus 123) for personal computer use. The spreadsheet format allows the user toe valuate impacts of various process options, coal feedstock characteristics, fuel characteristics, plant location sites, and plant sizes on fuel cost. Model flexibility reduces time and labor required to determine fuel costs and provides a basis to compare fuels manufactured by different processes. The model input includes coal characteristics, plant flowsheet definition, plant size, and market location. Based on these inputs, selected unit operations are chosen for coal processing

  7. Enrichment of trace elements in bottom ash from coal oxy-combustion: Effect of coal types

    CSIR Research Space (South Africa)

    Oboirien, BO

    2016-09-01

    Full Text Available In this study, the enrichment of trace elements in two coals under air and oxy-combustion conditions was studied. Twenty-one trace elements were evaluated. The two coal samples had a different concentration for the 21 trace elements, which was due...

  8. Comparative Study of Coal and Biomass Co-Combustion With Coal Burning Separately Through Emissions Analysis

    Directory of Open Access Journals (Sweden)

    Mohammad Siddique

    2016-06-01

    Full Text Available Appropriate eco-friendly methods to mitigate the problem of emissions from combustion of fossil fuel are highly demanded. The current study was focused on the effect of using coal & coal-biomass co-combustion on the gaseous emissions. Different biomass' were used along with coal. The coal used was lignite coal and the biomass' were tree waste, cow dung and banana tree leaves. Various ratios of coal and biomass were used to investigate the combustion behavior of coal-biomass blends and their emissions. The study revealed that the ratio of 80:20 of coal (lignite-cow dung and 100% banana tree leaves emits less emissions of CO, CO2, NOx and SO2 as compared to 100% coal. Maximum amount of CO emissions were 1510.5 ppm for banana tree waste and minimum amount obtained for lakhra coal and cow dung manure (70:30 of 684.667 ppm. Maximum percentage of SO2 (345.33 ppm was released from blend of lakhra coal and tree leaves (90:10 and minimum amount of SO2 present in samples is in lakhra coal-banana tree waste (80:20. The maximum amount of NO obtained for banana tree waste were 68 ppm whereas maximum amount of NOx was liberated from lakhra coal-tree leaves (60:40 and minimum amount from cow dung manure (30.83 ppm. The study concludes that utilization of biomass with coal could make remedial action against environment pollution.

  9. Combustion of coal gas fuels in a staged combustor

    Science.gov (United States)

    Rosfjord, T. J.; Mcvey, J. B.; Sederquist, R. A.; Schultz, D. F.

    1982-01-01

    Gaseous fuels produced from coal resources generally have heating values much lower than natural gas; the low heating value could result in unstable or inefficient combustion. Coal gas fuels may contain ammonia which if oxidized in an uncontrolled manner could result in unacceptable nitrogen oxide exhaust emission levels. Previous investigations indicate that staged, rich-lean combustion represents a desirable approach to achieve stable, efficient, low nitrogen oxide emission operation for coal-derived liquid fuels contaning up to 0.8-wt pct nitrogen. An experimental program was conducted to determine whether this fuel tolerance can be extended to include coal-derived gaseous fuels. The results of tests with three nitrogen-free fuels having heating values of 100, 250, and 350 Btu/scf and a 250 Btu/scf heating value doped to contain 0.7 pct ammonia are presented.

  10. Characterization of solid residues from coal liquefaction processes. Phase I

    Energy Technology Data Exchange (ETDEWEB)

    Potter, J.; McDougall, W.M.; Kybett, B.D.; Neufeld, C.

    1981-01-01

    Various coal liquefaction and beneficiation processes are being investigated by independent research groups sponsored by the Canadian Federal Government. These processes include the co-processing of heavy oils and bitumen with coal, oxygen removal and hydrogenation of coal and supercritical gas extraction of coal. The end products, gaseous and liquid fuels and insoluble organic residues, vary with the experimental conditions. The physical properties and origin of the insoluble residue may influence such factors as degree of conversion, efficiency of the process, and ultimately, gaseous and liquid yields. One of the most suitable methods of assessing the nature of the insoluble residues is the use of petrography. This report deals with petrographic assessment of the coals and residues from various coal conversion processes; attempts were made to characterize the solid phases in the residues; to assess them in a quantitative manner and where possible; to correlate the results with experimental data; and to assess their effects on conversion. (30 refs.)

  11. Advanced coal combustion technologies and their environmental impact

    International Nuclear Information System (INIS)

    Bozicevic, Maja; Feretic, Danilo; Tomsic, Zeljko

    1997-01-01

    Estimations of world energy reserves show that coal will remain the leading primary energy source for electricity production in the foreseeable future. In order to comply with ever stricter environmental regulations and to achieve efficient use of limited energy resources, advanced combustion technologies are being developed. The most promising are the pressurised fluidized bed combustion (PFBC) and the integrated gasification combined cycle (IGCC). By injecting sorbent in the furnace, PFBC removes more than 90 percent of SO 2 in flue gases without additional emission control device. In addition, due to lower combustion temperature, NO x emissions are around 90 percent lower than those from pulverised coal (PC) plant. IGCC plant performance is even more environmentally expectable and its high efficiency is a result of a combined cycle usage. Technical, economic and environmental characteristics of mentioned combustion technologies will be presented in this paper. Comparison of PFBC, IGCC and PC power plants economics and air impact will also be given. (Author)

  12. Char crystalline transformations during coal combustion and their implications for carbon burnout

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, R.H.

    1999-03-11

    Residual, or unburned carbon in fly ash affects many aspects of power plant performance and economy including boiler efficiency, electrostatic precipitator operation, and ash as a salable byproduct. There is a large concern in industry on the unburned carbon problem due to a variety of factors, including low-NOx combustion system and internationalization of the coal market. In recent work, it has been found that residual carbon extracted from fly ash is much less reactive than the laboratory chars on which the current kinetics are based. It has been suggested that thermal deactivation at the peak temperature in combustion is a likely phenomenon and that the structural ordering is one key mechanism. The general phenomenon of carbon thermal annealing is well known, but there is a critical need for more data on the temperature and time scale of interest to combustion. In addition, high resolution transmission electron microscopy (HRTEM) fringe imaging, which provides a wealth of information on the nature and degree of crystallinity in carbon materials such as coal chars, has become available. Motivated by these new developments, this University Coal Research project has been initiated with the following goals: to determine transient, high-temperature, thermal deactivation kinetics as a function of parent coal and temperature history; and to characterize the effect of this thermal treatment on carbon crystalline structure through high-resolution transmission electron microscopy and specialized, quantitative image analysis.

  13. Char crystalline transformations during coal combustion and their implications for carbon burnout

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, R.H.

    1999-07-07

    Residual, or unburned carbon in fly ash affects many aspects of power plant performance and economy including boiler efficiency, electrostatic precipitator operation, and ash as a salable byproduct. There is a large concern in industry on the unburned carbon problem due to a variety of factors, including low-NOx combustion system and internationalization of the coal market. In recent work, it has been found that residual carbon extracted from fly ash is much less reactive than the laboratory chars on which the current kinetics are based. It has been suggested that thermal deactivation at the peak temperature in combustion is a likely phenomenon and that the structural ordering is one key mechanism. The general phenomenon of carbon thermal annealing is well known, but there is a critical need for more data on the temperature and time scale of interest to combustion. In addition, high resolution transmission electron microscopy (HRTEM) fringe imaging, which provides a wealth of information on the nature and degree of crystallinity in carbon materials such as coal chars, has become available. Motivated by these new developments, this University Coal Research project has been initiated with the following goals: (1) To determine transient, high-temperature, thermal deactivation kinetics as a function of parent coal and temperature history. (2) To characterize the effect of the thermal treatment on carbon crystalline structure through high-resolution transmission electron microscopy and specialized, quantitative image analysis.

  14. Impacts of heavy metals and radioactivity from coal combustion

    International Nuclear Information System (INIS)

    Goldman, M.

    1977-01-01

    Coal-fueled plants appear to have the potential for a slightly higher radiologic impact on the population than do nuclear-powered plants although in both cases the impact appears to be quite small. The additional impact from trace elements in and on respirable fly ash is of concern and should be factored into the total assessment of potential health consequences associated with a major increase in coal combustion. For some time the paucity of essential data will hamper realistic evaluations

  15. Characterising the combustion behaviour of New Zealand coals by thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Benfell, K.E.; Beamish, B.B.; Rodgers, K.A. [University of Auckland, Auckland (New Zealand). Dept. of Geology

    1995-12-31

    Thirty-three New Zealand coals were subjected to thermogravimetric analysis (TG) and derivative thermogravimetric analysis (DTG) to evaluate the techniques` applicability to New Zealand coals. Generally, New Zealand sub-bituminous coals have lower burnout temperatures than bituminous coals. However, local and regional differences occur, where some sub-bituminous coals show both higher and lower char burnout temperatures than may be otherwise expected from their rank and T{sub 6} values (the peak temperature where the rate of weight loss of the sample is the greatest). There is a sizeable variations in the char burnout temperature (T{sub 8}) (465 to 636{degree}C) in coals with volatile matter contents above 40%, whereas coals with lower volatile contents have T{sub 8} values around 646{degree}C. The temperature of char burnout gives a better indication of combustion efficiency than rank or volatile matter content alone. Industrial operators could use this technique to provide an indication of burnout performance before a coal is purchased, assisting evaluation of the coal`s suitability for a particular usage. 10 refs., 4 figs., 3 tabs.

  16. Reactivity and NO emissions of coal blends during combustion

    Energy Technology Data Exchange (ETDEWEB)

    B. Arias; R.I. Backreedy; A. Arenillas; J.M. Jones; F. Rubiera; M. Pourkashanian; A. Williams; J.J. Pis [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2003-07-01

    This work is focussed on burnout and NO emissions during coal blend combustion. Two different approaches were used. In a first step, experimental work was carried out in a laminar entrained flow reactor (EFR) and then computational techniques were applied to improve the burnout prediction of coals and blend during the experiments. A preliminary study on the combustibility of the samples was made using a thermogravimetric analyser. An entrained flow reactor was employed to study the behaviour of coals and blends at high heating rate and short residence times. Burnout and NO emissions were measured during these experiments. Two methods were used to modelling the combustion in the entrained flow reactor: a commercial CFD code and an advanced char burnout model. Experiments done in the EFR showed that burnout and NO emissions of some blends can be predicted from the weighted average of the values of individual coals, especially when blended coals have the same rank. When a blend is made with coals of different rank, some deviations were observed with respect to the averaged values in burnout and especially in NOx emissions. Burnouts predicted with a commercial CFD code were higher than the experimental values. The use of an advanced char burnout model improved greatly the results, showing the advantages of coupling these two mathematical techniques. 9 refs., 7 figs., 2 tabs.

  17. Method and device for the combustion of pulverised coal

    Energy Technology Data Exchange (ETDEWEB)

    Schoppe, F

    1977-01-13

    Until now, high combustion space loadings in pulverised coal firing were only obtained with melting combustion, where the ash is fluid. The disadvantage of this is that part of the heating surface is covered by liquid slack, and this type of combustion cannot operate in 'on-off operation', as the slack solidifies when the boiler is switched off. According to the invention, however, pulverised coal, which is reluctant to react, can be burnt at high combustion space loadings of over 2000 Mcal/cu. metre. hour. atm. with dry ash extraction, so that its use is possible for the combustion in central heating plants in detached houses and blocks of flats, with 'on-off operation'. For this purpose, the pulverised coal is heated under excess pressure in an atmosphere with a maximum of 10% of oxygen with a speed of heating of 1000/sup 0/C/sec up to 100 to 150/sup 0/C above its ignition temperature, and can be blown into the combustion air. Tangentially to the flame jet, a cold gas flow is guided so that burning particles thrown out at the sides are cooled below the ash melting temperature, before they reach the walls. The burning flame jet is accelerated, by using the excess pressure, via an injector, into a zone at less than the ash melting temperature, so that dry ash extraction is guaranteed.

  18. Unburned carbon in combustion residues from mainly solid biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem H; Lind B; Lagerkvist A

    2012-02-15

    Unburned carbon in 21 combustion residues from solid biofuels is investigated using several methods of analysis (a.o. LOI and TOC), as well as micro-Raman spectroscopy. The results are used to discuss the distribution of unburned carbon in the residues from the different combustion plants and its nature (organic or elemental). The consequences of the elemental nature of carbon for environmental properties of the residue are noted

  19. Energetics of coal substitution by briquettes of agricultural residues

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, Pallav; Tripathi, Arun Kumar; Kandpal, Tara Chandra [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India)

    2006-07-15

    The suitability of using biomass briquettes to substitute coal is debatable, as a substantial amount of energy is required for briquetting of biomass. In the present work, an attempt to evaluate the energetic viability of briquetting of agricultural residues compared with the energy embodied in coal in India has been made. Briquetting of agricultural residues is not found to be an energetically viable option even for locations at a distance of about 1500km from the coal pithead (even if the briquetting unit is located very close to the place of availability of the agricultural residues). A need for transportation of agricultural residues further pushes this critical distance upwards. (author)

  20. Novel use of residue from direct coal liquefaction process

    Energy Technology Data Exchange (ETDEWEB)

    Jianli Yang; Zhaixia Wang; Zhenyu Liu; Yuzhen Zhang [Chinese Academy of Sciences, Taiyuan (China). State Key Laboratory of Coal Conversion

    2009-09-15

    Direct coal liquefaction residue (DCLR) is, commonly, designed to be used as a feed stock for gasification or combustion. Use of DCLR as a value added product is very important for improving overall economy of direct coal liquefaction processes. This study shows that the DCLR may be used as a pavement asphalt modifier. The modification ability is similar to that of Trinidad Lake Asphalt (TLA), a superior commercial modifier. Asphalts modified by two DCLRs meet the specifications of ASTM D5710 and BSI BS-3690 designated for the TLA-modified asphalts. The required addition amount for the DCLRs tested is less than that for TLA due possibly to the high content of asphaltene in DCLRs. Different compatibility was observed for the asphalts with the same penetration grade but from the different origin. Different components in the DCLR play different roles in the modification. Positive synergetic effects among the fractions were observed, which may due to the formation of the stable colloid structure. Unlike polymer-type modifier, the structure of asphalt-type modifier has a similarity with petroleum asphalts which favors the formation of a stable dispersed polar fluid (DPF) colloid structure and improves the performance of pavement asphalt. 12 refs., 1 fig., 6 tabs.

  1. Method for increasing the calorific value of gas produced by the in situ combustion of coal

    Science.gov (United States)

    Shuck, Lowell Z.

    1978-01-01

    The present invention relates to the production of relatively high Btu gas by the in situ combustion of subterranean coal. The coal bed is penetrated with a horizontally-extending borehole and combustion is initiated in the coal bed contiguous to the borehole. The absolute pressure within the resulting combustion zone is then regulated at a desired value near the pore pressure within the coal bed so that selected quantities of water naturally present in the coal will flow into the combustion zone to effect a hydrogen and carbon monoxide-producing steam-carbon reaction with the hot carbon in the combustion zone for increasing the calorific value of the product gas.

  2. Sulfur retention by ash during coal combustion. Part I. A model of char particle combustion

    Directory of Open Access Journals (Sweden)

    BORISLAV GRUBOR

    2003-02-01

    Full Text Available A model for the combustion of porous char particles as a basis for modeling the process of sulfur retention by ash during coal combustion is developed in this paper. The model belongs to the microscopic intrinsic models and describes the dynamic behavior of a porous char particle during comustion, taking into account temporal and spatial changes of all important physical properties of the char particle and various combustion parameters. The parametric analysis of the enhanced model shows that the model represents a good basis for the development of a model for the process of sulfur retention by ash during coal combustion. The model enables the prediction of the values of all parameters necessary for the introduction of reactions between sulfur compounds and mineral components in ash, primarily calcium oxide.

  3. Experimental research on combustion fluorine retention using calcium-based sorbents during coal combustion (II)

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Q.; Ma, X.; Liu, J.; Wu, X.; Zhou, J.; Cen, K. [Liaoning Technical University, Fuxin (China). College of Resource and Environment Engineering

    2008-12-15

    Fluoride pollution produced by coal burning can be controlled with the calcium-based sorbent combustion fluorine technique in which calcium-based sorbents are mixed with the coal or sprayed into the combustion chamber. In a fixed bed tube furnace combustion experiment using one calcium-based natural mineral, limestone and one calcium-based building material, it was shown that the calcium-based sorbent particle grain size and pore structure have a big influence on the combustion fluorine retention effect. Reducing the calcium-based sorbent particle grain size and improving the calcium sorbent structure characteristics at very high temperature to enhance the fluorine retention effect is the important approach to the fluorine retention agent development. 8 refs., 1 fig., 5 tabs.

  4. Transformations of inorganic coal constituents in combustion systems

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J. (ed.); Srinivasachar, S.; Wilemski, G.; Boni, A.A. (PSI Technology Co., Andover, MA (United States)); Kang, Shin-Gyoo; Sarofim, A.F.; Graham, K.A.; Beer, J.M. (Massachusetts Inst. of Tech., Cambridge, MA (United States)); Peterson, T.W.; Wendt, J.O.L.; Gallagher, N.B.; Bool, L. (Arizona Univ., Tucson, AZ (United States)); Huggins, F.E.; Huffman, G.P.; Shah, N.; Shah, A. (Kentucky Univ., Lexingt

    1992-11-01

    The inorganic constituents or ash contained in pulverized coal significantly increase the environmental and economic costs of coal utilization. For example, ash particles produced during combustion may deposit on heat transfer surfaces, decreasing heat transfer rates and increasing maintenance costs. The minimization of particulate emissions often requires the installation of cleanup devices such as electrostatic precipitators, also adding to the expense of coal utilization. Despite these costly problems, a comprehensive assessment of the ash formation and had never been attempted. At the start of this program, it was hypothesized that ash deposition and ash particle emissions both depended upon the size and chemical composition of individual ash particles. Questions such as: What determines the size of individual ash particles What determines their composition Whether or not particles deposit How combustion conditions, including reactor size, affect these processes remained to be answered. In this 6-year multidisciplinary study, these issues were addressed in detail. The ambitious overall goal was the development of a comprehensive model to predict the size and chemical composition distributions of ash produced during pulverized coal combustion. Results are described.

  5. Co-combustion of anthracite coal and wood pellets: Thermodynamic analysis, combustion efficiency, pollutant emissions and ash slagging.

    Science.gov (United States)

    Guo, Feihong; Zhong, Zhaoping

    2018-08-01

    This work presents studies on the co-combustion of anthracite coal and wood pellets in fluidized bed. Prior to the fluidized bed combustion, thermogravimetric analysis are performed to investigate the thermodynamic behavior of coal and wood pellets. The results show that the thermal decomposition of blends is divided into four stages. The co-firing of coal and wood pellets can promote the combustion reaction and reduce the emission of gaseous pollutants, such as SO 2 and NO. It is important to choose the proportion of wood pellets during co-combustion due to the low combustion efficiency caused by large pellets with poor fluidization. Wood pellets can inhibit the volatilization of trace elements, especially for Cr, Ni and V. In addition, the slagging ratio of wood pellets ash is reduced by co-firing with coal. The research on combustion of coal and wood pellets is of great significance in engineering. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Nitrogen Chemistry in Fluidized Bed Combustion of Coal

    DEFF Research Database (Denmark)

    Jensen, Anker Degn

    and reduction by homogeneous and heterogeneous reactions. The data for the estimation of kinetics of the heterogeneous reactions were measured by one of the partners in the project for char and bed material sampled from a pressurized FBC pilot plant burning Kiveton Park coal. Experimental data from the pilot...... plant were used for model verification. The simulations of the NO emission during staged combustion and NH3 injection for NO reduction were in qualitative agreement with the experimental data. A parametric study of the influence of operating conditions on the conversion of fuel-N to NO showed......, the gas interchange coefficient, the bubble size and the bubble rise velocity. The most important combustion parameters were the rate of CO and CH4 combustion and the fraction of CO produced from char combustion. By using a rate of production analysis, the important reactions in the NO model were...

  7. Grindability and combustion behavior of coal and torrefied biomass blends.

    Science.gov (United States)

    Gil, M V; García, R; Pevida, C; Rubiera, F

    2015-09-01

    Biomass samples (pine, black poplar and chestnut woodchips) were torrefied to improve their grindability before being combusted in blends with coal. Torrefaction temperatures between 240 and 300 °C and residence times between 11 and 43 min were studied. The grindability of the torrefied biomass, evaluated from the particle size distribution of the ground sample, significantly improved compared to raw biomass. Higher temperatures increased the proportion of smaller-sized particles after grinding. Torrefied chestnut woodchips (280 °C, 22 min) showed the best grinding properties. This sample was blended with coal (5-55 wt.% biomass). The addition of torrefied biomass to coal up to 15 wt.% did not significantly increase the proportion of large-sized particles after grinding. No relevant differences in the burnout value were detected between the coal and coal/torrefied biomass blends due to the high reactivity of the coal. NO and SO2 emissions decreased as the percentage of torrefied biomass in the blend with coal increased. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Ultrafine ash aerosols from coal combustion: Characterization and health effects

    Energy Technology Data Exchange (ETDEWEB)

    William P. Linak; Jong-Ik Yoo; Shirley J. Wasson; Weiyan Zhu; Jost O.L. Wendt; Frank E. Huggins; Yuanzhi Chen; Naresh Shah; Gerald P. Huffman; M. Ian Gilmour [US Environmental Protection Agency, Research Triangle Park, NC (United States). National Risk Management Research Laboratory

    2007-07-01

    Ultrafine coal fly-ash particles withdiameters less than 0.5 {mu}m typically comprise less than 1% of the total fly-ash mass. This paper reports research focused on both characterization and health effects of primary ultrafine coal ash aerosols alone. Ultrafine, fine, and coarse ash particles were segregated and collected from a coal burned in a 20 kW laboratory combustor and two additional coals burned in an externally heated drop tube furnace. Extracted samples from both combustors were characterized by transmission electron microscopy (TEM), wavelength dispersive X-ray fluorescence(WD-XRF) spectroscopy, Moessbauer spectroscopy, and X-ray absorption fine structure (XAFS) spectroscopy. Pulmonary inflammation was characterized by albumin concentrations in mouse lung lavage fluid after instillation of collected particles in saline solutions and a single direct inhalation exposure. Results indicate that coal ultrafine ash sometimes contains significant amounts of carbon, probably soot originating from coal tar volatiles, depending on coal type and combustion device. Surprisingly, XAFS results revealed the presence of chromium and thiophenic sulfur in the ultrafine ash particles. The instillation results suggested potential lung injury, the severity of which could be correlated with the carbon (soot) content of the ultrafines. This increased toxicity is consistent with theories in which the presence of carbon mediates transition metal (i.e., Fe) complexes, as revealed in this work by TEM and XAFS spectroscopy, promoting reactive oxygenspecies, oxidation-reduction cycling, and oxidative stress. 24 refs., 7 figs.

  9. Partitioning of elements during coal combustion and leaching experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wen-feng; Qin Yong; Song Dang-yu; Wang Jun-yi [China University of Mining & Technology, Xuzhou (China). School of Resources and Earth Science

    2009-04-15

    The mineral component and content of sulfur and 42 major and trace elements of the feed coal, fly and bottom ashes collected from Shizuishan coal-fired power plant, Ningxia, China were analyzed using AFS, INAA, ICP-MS, ICP-AES, XRD. Based on the coal combustion and leaching experiments, the partitioning of these elements during coal combustion and the leaching behavior of the 11 potentially hazardous elements, including As, Cd, Co, Cr, Hg, Mo, Ni, Pb, Se, Th and U were investigated. The results show that the distribution of elements in the fly and bottom ashes is controlled by their volatilities and modes of occurrence in the coal. The degree of volatilization of elements may be mainly associated with boiling/melting points of these elements and their compounds. The elements easily volatilized, organically bound or associated with sub-micrometer and nano minerals (e.g. Al and Na) tend to be enriched in the fine fractions of fly ash, and most elements do not vaporize which are approximately equally partitioned in the fly and bottom ashes. The emission rates of As, Cr, K, Mg, Mn, Mo, Pb, Sb, and Zn are notably influenced by the temperature ranging from 877 to 1300{sup o}C. The leaching behavior of elements depend significantly on their geochemical properties and modes of occurrence. The elements with a low degree of volatilization are not easily leached, while volatile elements easily leached under the acid conditions. Arsenic, B Br, Cd, Cu, Hg, Pb, S, Sb and Se show a higher emission rate during coal combustion, and the leached concentrations of Cd, Co, Mo, Ni and U in the acid media exceed their limited concentrations recommended in relevant environment quality standards for water, which will harm the environment. 32 refs., 4 figs., 4 tabs.

  10. Pressurized oxy-coal combustion: Ideally flexible to uncertainties

    International Nuclear Information System (INIS)

    Zebian, Hussam; Mitsos, Alexander

    2013-01-01

    Simultaneous multi-variable gradient-based optimization with multi-start is performed on a 300 MWe wet-recycling pressurized oxy-coal combustion process with carbon capture and sequestration, subject to uncertainty in fuel, ambient conditions, and other input specifications. Two forms of flue gas thermal recovery are studied, a surface heat exchanger and a direct contact separation column. Optimization enables ideal flexibility in the processes: when changing the coal utilized, the performance is not compromised compared to the optimum performance of a process specifically designed for that coal. Similarly, the processes are immune to other uncertainties like ambient conditions, air flow, slurry water flow, atomizer stream flow and the oxidizer stream oxygen purity. Consequently, stochastic programming is shown to be unnecessary. Close to optimum design, the processes are also shown to be insensitive towards design variables such as the areas of the feedwater heaters. Recently proposed thermodynamic criteria are used as embedded design specifications in the optimization process, rendering it faster and more robust. - Highlights: • Proposed formulation to assess the flexibility of power generation processes facing uncertainties. • Obtained ideal flexibility of pressurized oxy-coal combustion with respect to coal type. • Performance of processes under uncertainty match performance of optimal processes for specific set of inputs. • Stochastic programming is not required and instead hierarchic optimization is utilized

  11. Study on the influence of electromagnetic field on the property of coal combustion burnout in circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Y. [Ruiping Coal and Electric Power Ltd. Co., Ruzhou (China)

    2008-08-15

    To study the influences of electromagnetism field pretreatment of pulverized Coal (EFPPC) on the properties of its combustion, thermogravimetric analysis, a Muffle furnace experiment and an X-ray diffraction experiment were carried out for three Coal banks. It was shown that EFPPC will induce the molecular structure of Coal to change into amorphous carbon, which causes an increase in the rate of oxygen absorption during the initial stages of Coal burning and reaction activity. It is also shown that the residual carbon of bituminous Coal would be increased by about 0.33% - 0.41%, i.e, the loss of standard Coal is about 3,000 t/a for double 480 t/h boilers, when applying EFPPC for 1 min at a temperature of 800 - 1,000 {sup o}C. When the temperature increases 200 {sup o}C, the residual carbon increases by about 2.07% but the effect of EFPPC is less than 0.21% for bituminous Coal and residual carbon is about 1.47% and the effect of EFPPC is less than 0.05% for lean Coal. Therefore the effect of increasing the temperature of EFPPC on residual carbon is less than that of increasing the time of EFPPC. 9 refs., 4 figs., 2 tabs.

  12. Coal-water slurry fuel internal combustion engine and method for operating same

    Science.gov (United States)

    McMillian, Michael H.

    1992-01-01

    An internal combustion engine fueled with a coal-water slurry is described. About 90 percent of the coal-water slurry charge utilized in the power cycle of the engine is directly injected into the main combustion chamber where it is ignited by a hot stream of combustion gases discharged from a pilot combustion chamber of a size less than about 10 percent of the total clearance volume of main combustion chamber with the piston at top dead center. The stream of hot combustion gases is provided by injecting less than about 10 percent of the total coal-water slurry charge into the pilot combustion chamber and using a portion of the air from the main combustion chamber that has been heated by the walls defining the pilot combustion chamber as the ignition source for the coal-water slurry injected into the pilot combustion chamber.

  13. Evaluation of catalytic combustion of actual coal-derived gas

    Science.gov (United States)

    Blanton, J. C.; Shisler, R. A.

    1982-01-01

    The combustion characteristics of a Pt-Pl catalytic reactor burning coal-derived, low-Btu gas were investigated. A large matrix of test conditions was explored involving variations in fuel/air inlet temperature and velocity, reactor pressure, and combustor exit temperature. Other data recorded included fuel gas composition, reactor temperatures, and exhaust emissions. Operating experience with the reactor was satisfactory. Combustion efficiencies were quite high (over 95 percent) over most of the operating range. Emissions of NOx were quite high (up to 500 ppm V and greater), owing to the high ammonia content of the fuel gas.

  14. TOXIC SUBSTANCES FROM COAL COMBUSTION-A COMPREHENSIVE ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    C.L. Senior; F. Huggins; G.P. Huffman; N. Shah; N. Yap; J.O.L. Wendt; W. Seames; M.R. Ames; A.F. Sarofim; S. Swenson; J.S. Lighty; A. Kolker; R. Finkelman; C.A. Palmer; S.J. Mroczkowski; J.J. Helble; R. Mamani-Paco; R. Sterling; G. Dunham; S. Miller

    2001-06-30

    The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. With support from the National Energy Technology Laboratory (NETL), the Electric Power Research Institute, and VTT (Finland), Physical Sciences Inc. (PSI) has teamed with researchers from USGS, MIT, the University of Arizona (UA), the University of Kentucky (UK), the University of Connecticut (UC), the University of Utah (UU) and the University of North Dakota Energy and Environmental Research Center (EERC) to develop a broadly applicable emissions model useful to regulators and utility planners. The new Toxics Partitioning Engineering Model (ToPEM) will be applicable to all combustion conditions including new fuels and coal blends, low-NOx combustion systems, and new power generation plants. Development of ToPEM will be based on PSI's existing Engineering Model for Ash Formation (EMAF). The work discussed in this report covers the Phase II program. Five coals were studied (three in Phase I and two new ones in Phase II). In this work UK has used XAFS and Moessbauer spectroscopies to characterize elements in project coals. For coals, the principal use was to supply direct information about certain hazardous and other key elements (iron) to complement the more complete indirect investigation of elemental modes of occurrence being carried out by colleagues at USGS. Iterative selective leaching using ammonium acetate, HCl, HF, and HNO3, used in conjunction with mineral identification/quantification, and microanalysis of individual mineral grains, has allowed USGS to delineate modes of occurrence for 44 elements. The Phase II coals show rank-dependent systematic differences in trace-element modes of occurrence. The work at

  15. Mercury speciation in air-coal and oxy-coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hui; Duan, Yufeng; Mao, Yongqiu [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    To study the effect of air-coal and oxy-coal combustion on mercury emission, Xuzhou bituminous coal was burnt in a 6 kWth fluidized bed at 800 and 850 C in four atmospheres: air, 21%O{sub 2}/79%CO{sub 2}, 30%O{sub 2}/70%CO{sub 2}, 40%O{sub 2}/60%CO{sub 2} analysed with an online flue gas analyzer. Ontario Hydro method (OHM) was employed to measure mercury speciation in flue gas. The result indicated that more elemental mercury and oxidized mercury are released when burned in O{sub 2}/CO{sub 2} atmosphere than in air at 800 C, while the situation is just opposite, when coal was burnt at 850 C, less Hg{sup 0} and Hg{sup 2+} in O{sub 2}/CO{sub 2} atmosphere than in air. The concentration of Hg{sup 0} rises as temperature increases both in the conditions of the air combustion and oxy-coal combustion, but the concentration of Hg{sup 2+} increases with the increase of temperature only in the condition of air combustion and decreases in the oxy-coal combustion. With the increase of the oxygen concentration which is in the range of 21-40%, the concentrations of Hg{sup 0} and Hg{sup 2+} decrease first and then increase. When excess air coefficient increases, the oxygen content is higher and the vaporization rate of Hg{sup 0} and Hg{sup 2+} decrease.

  16. Effect of combustion characteristics on wall radiative heat flux in a 100 MWe oxy-coal combustion plant

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.; Ryu, C. [Sungkyunkwan Univ., Suwon (Korea, Republic of). School of Mechanical Engineering; Chae, T.Y. [Sungkyunkwan Univ., Suwon (Korea, Republic of). School of Mechanical Engineering; Korea Institute of Industrial Technology, Cheonan (Korea, Republic of). Energy System R and D Group; Yang, W. [Korea Institute of Industrial Technology, Cheonan (Korea, Republic of). Energy System R and D Group; Kim, Y.; Lee, S.; Seo, S. [Korea Electric Power Research Institute (KEPRI), Daejeon (Korea, Republic of). Power Generation Lab.

    2013-07-01

    Oxy-coal combustion exhibits different reaction, flow and heat transfer characteristics from air-coal combustion due to different properties of oxidizer and flue gas composition. This study investigated the wall radiative heat flux (WRHF) of air- and oxy-coal combustion in a simple hexahedral furnace and in a 100 MWe single-wall-fired boiler using computational modeling. The hexahedral furnace had similar operation conditions with the boiler, but the coal combustion was ignored by prescribing the gas properties after complete combustion at the inlet. The concentrations of O{sub 2} in the oxidizers ranging between 26 and 30% and different flue gas recirculation (FGR) methods were considered in the furnace. In the hexahedral furnace, the oxy-coal case with 28% of O{sub 2} and wet FGR had a similar value of T{sub af} with the air-coal combustion case, but its WRHF was 12% higher. The mixed FGR case with about 27% O{sub 2} in the oxidizer exhibited the WRHF similar to the air-coal case. During the actual combustion in the 100 MWe boiler using mixed FGR, the reduced volumetric flow rates in the oxy-coal cases lowered the swirl strength of the burners. This stretched the flames and moved the high temperature region farther to the downstream. Due to this reason, the case with 30% O{sub 2} in the oxidizers achieved a WRHF close to that of air-coal combustion, although its adiabatic flame temperature (T{sub af}) and WHRF predicted in the simplified hexahedral furnace was 103 K and 10% higher, respectively. Therefore, the combustion characteristics and temperature distribution significantly influences the WRHF, which should be assessed to determine the ideal operating conditions of oxy- coal combustion. The choice of the weighted sum of gray gases model (WSGGM) was not critical in the large coal-fired boiler.

  17. Influence of the microwave irradiation dewatering on the combustion characteristics of Chinese brown coals

    Science.gov (United States)

    Ge, Lichao; Feng, Hongcui; Xu, Chang; Zhang, Yanwei; Wang, Zhihua

    2018-02-01

    This study investigates the influence of microwave irradiation on coal composition, pore structure, coal rank, and combustion characteristics of typical brown coals in China. Results show that the upgrading process significantly decreased the inherent moisture, and increased calorific value and fixed carbon content. After upgrading, pore distribution extended to micropore region, oxygen functional groups were reduced and destroyed, and the apparent aromaticity increased suggesting an improvement in the coal rank. Based on thermogravimetric analysis, the combustion processes of upgraded coals were delayed toward the high temperature region, and the temperatures of ignition, peak and burnout increased. Based on the average combustion rate and comprehensive combustion parameter, the upgraded coals performed better compared with raw brown coals and a high rank coal. In ignition and burnout segments, the activation energy increased but exhibited a decrease in the combustion stage.

  18. Speciation of arsenic in Canadian feed-coal and combustion by-products

    Energy Technology Data Exchange (ETDEWEB)

    F. Goodarzi; F.E. Huggins [Natural Resourses Canada (Canada). Geological Survey of Canada-Calgary Division

    2003-07-01

    It is important to determine the oxidation state of arsenic in coal and coal combustion products, as this is generally the single most critical factor determining the toxicity of this element towards humans. However, the same factor is also important for understanding the volatility and reactions of arsenic forms in combustion and their leachability and mobility in ash-disposal situations. In this work, XAFS spectroscopy has been used to examine the speciation of arsenic in Canadian subbituminous and bituminous feed-coals and their combustion products. The concentration of arsenic in the feed-coals varied from < 2 ppm for subbituminous to 54 ppm for bituminous coals. Significant differences were noted in how arsenic occurs in subbituminous and bituminous coals, but, although such differences might influence the initial volatility and reactions of arsenic during coal combustion, arsenic is found almost entirely in the less toxic As{sup 5+} oxidation state in combustion products from both types of coal. (Abstract only)

  19. Role of coal combustion products in sustainable construction materials

    Energy Technology Data Exchange (ETDEWEB)

    Naik, T.R.; Siddique, R.; Vaniker, S. [University of Wisconsin-Milwaukee, Milwaukee, WI (USA). UWM Center for Products Utilization, College of Engineering and Applied Science

    2003-07-01

    The paper describes various coal combustion products, CCPs produced in the process of power generation. These include fly ash, bottom ash, boiler slag and flue gas desulfurization products. Typical test protocol used for testing, analysis and evaluation of CCPs, as well as the current best recycling use options for these materials are discussed. Materials, productions, properties, and potential applications in the manufacture of emerging materials for sustainable construction, as well as environmental impact are also briefly discussed. 47 refs., 16 figs., 8 tabs.

  20. Study experimental of the combustion of coal in grill

    International Nuclear Information System (INIS)

    Chejne j, Farid; Florez E, Whady and others

    1997-01-01

    In this article, experiments in which the temperature of the bed and emissions in the combustion chamber were registered were carried out in pilot plant. Also proximate analyses of coal sizing over the average of unburned carbon was studied in pilot plant and industrial boilers. Finally, graphics of CO vs O2, Nox vs temperature and Sox vs temperature were analyzed in order to determinate their kinetic behavior

  1. Combustion characteristics of intensively cleaned coal fractions. Effect of mineral matter

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Arenillas, A.; Fuente, E.; Pis, J.J. [Inst. Nacional de Carbon, Oviedo (Spain); Ivatt, S. [ETSU, Harwell, Didcot (United Kingdom)

    1997-12-31

    The purpose of this work has been to assess the effect that intensive coal cleaning exerts on the combustion behaviour of different density-separated coal fractions. Samples with ash contents varying from 39% for the raw coal, to 2% for the cleanest fraction were obtained after density separation. Temperature-programmed combustion and isothermal gasification in air were used to measure the reactivities of the parent coal and the cleaned fractions. Coal and char reactivities increased with increasing ash content of the samples. Thermal analysis-mass spectrometry of the low-temperature ashes was also carried out in order to study the reactions of coal minerals under combustion conditions. (orig.)

  2. Co-combustion of coal and meat and bone meal

    Energy Technology Data Exchange (ETDEWEB)

    I. Gulyurtlu; D. Boavida; P. Abelha; M.H. Lopes; I. Cabrita [DEECA-INETI, Lisbon (Portugal)

    2005-12-01

    Feeding meat and bone meal (MBM) to cattle, sheep or other animals has been banned within the EU since 1 of July 1994. The quantities to be eliminated are measured in millions of tons. Disposal to landfill is not an option, as simply burying the material cannot destroy any potential bovine spongiform encephalopathy (BSE) pathogens. One disposal option is the co-combustion of coal and MBM, to ensure that any living organism is totally thermally destroyed and at the same time valorising its energetic potential. Fluidised bed co-combustion of MBM is considered a viable technological option as it has the flexibility to burn coal with different materials in an efficient way, at relatively low temperatures (750-850{sup o}C) with lower environmental impact. For this purpose, co-combustion tests of coal and MBM were carried out on a pilot scale FBC, to investigate the implications of the results. This involved the determination of the emissions of pollutants like NOx, N{sub 2}O, VOC, CO{sub 2}, as well as the composition and the valorisation of the ashes produced. The ashes from the bed, the cyclones and the stack were collected and analyzed for biological activity, ecotoxicity, heavy metal concentration and leachability. The results obtained suggest that the ashes were suitable to be deposited in municipal landfills. 23 refs., 10 figs., 10 tabs.

  3. Influence of Process Parameters on Coal Combustion Performance

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der

    investigated experimentally in a 400 MWe corner fired boiler with over fire air, a 350 MWe opposed fired boiler, and in a 160 kWt pilot scale test rig. Three different coals were fired in each of the furnaces as part of the activities in group 3 of the European Union JOULE 2 Extension project "Atmospheric......The objective of this study is to improve the understanding of nitrogen oxide formation and carbon burnout during the combustion of pulverized coal, and to contribute to addressing the potential of chemical engineering models for the prediction of furnace temperatures, NO emissions and the amount...... of carbon in ash. To this purpose, the effect of coal quality on NO and burnout has been investigated experimentally, a radiation heat balance has been developed based on simple chemical engineering methodology, and a mixing study has been conducted in order to describe the near burner macro mixing in terms...

  4. Balance of natural radionuclides in the brown coal based power generation and harmlessness of the residues and side product utilization; Bilanz natuerlicher Radionuklide in der Braunkohleverstromung und Unbedenklichkeit bei der Verwendung von Rueckstaenden und Nebenprodukten

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Hartmut; Kunze, Christian; Hummrich, Holger [IAF-Radiooekologie GmbH, Radeberg (Germany)

    2017-04-01

    During brown coal combustion a partial enrichment of natural radionuclides occurs in different residues. Residues and side product from brown coal based power generation are used in different ways, for example filter ashes and gypsum from flue gas desulfurization facilities are used in the construction materials fabrication and slags for road construction. Detailed measurement and accounting of radionuclides in the mass throughputs in coal combustion power plants have shown that the utilized gypsum and filter ashes are harmless in radiologic aspects.

  5. Coal-char combustion in a fluidised bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mehrotra, S.P.; Pande, M. [Indian Institute of Technolgy, Kanpur (India)

    2001-12-01

    Combustion of bituminous coal chars ranging from 0.8 mm to 1.8 mm has been studied in a fluidised bed reactor at temperatures ranging from 500 to 850{sup o}C. The fluidised bed consists of inert sand particles of average size of 0.5 mm and reactive coal char particles. A heat balance has been worked out to calculate the rate of combustion of char from measured incremental changes in the bed temperature during combustion. Investigations on partially burnt particles suggest that the ash layer which builds up around the burning core of char particles is non-flaking and the particles burn in a shrinking core manner. Analysis of rate data indicates that the rate of combustion is controlled by chemical reaction kinetics, though diffusion of oxygen through the bundary layer begins to influence the overall reaction kinetics at higher temperatures. The burnt out time varies linearly with particle size. Activation energy for the chemical reaction control regime is found to be around 68 kJ/mole.

  6. Combustion studies of coal derived solid fuels by thermogravimetric analysis. III. Correlation between burnout temperature and carbon combustion efficiency

    Science.gov (United States)

    Rostam-Abadi, M.; DeBarr, J.A.; Chen, W.T.

    1990-01-01

    Burning profiles of 35-53 ??m size fractions of an Illinois coal and three partially devolatilized coals prepared from the original coal were obtained using a thermogravimetric analyzer. The burning profile burnout temperatures were higher for lower volatile fuels and correlated well with carbon combustion efficiencies of the fuels when burned in a laboratory-scale laminar flow reactor. Fuels with higher burnout temperatures had lower carbon combustion efficiencies under various time-temperature conditions in the laboratory-scale reactor. ?? 1990.

  7. Aspects of combustion behaviour of coals from some New Zealand lignite-coal regions determined by thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Benfell, K.E.; Beamish, B.B.; Rodgers, K.A. [University of Newcastle, Callaghan, NSW (Australia). Dept. of Geology

    1997-08-25

    The papers describes how thermogravimetric analysis of five Late Cretaceous and Cenozoic New Zealand lignites demonstrate that their combustion behaviour is distinct from that of subbituminous coals and may be characterised by peak temperature of 377-416{degree}C, maximum rate of combustion of 25-31 wt% min{sup -1}, and temperature of char burnout 421-497{degree}C. These parameters reflect variation in thermal behaviour associated with both the organic and inorganic constituents of the coal. The information obtained is additional to that provided by proximate analysis; the latter is insufficient to predict the combustion behaviour of the coals relative to one another. A post-combustion thermal event is seen among the lignites as in other low-rank coals combusting below 600{degree}C, which appears to be related to the organic sulphur content of the coal.

  8. Mercury stable isotope signatures of world coal deposits and historical coal combustion emissions.

    Science.gov (United States)

    Sun, Ruoyu; Sonke, Jeroen E; Heimbürger, Lars-Eric; Belkin, Harvey E; Liu, Guijian; Shome, Debasish; Cukrowska, Ewa; Liousse, Catherine; Pokrovsky, Oleg S; Streets, David G

    2014-07-01

    Mercury (Hg) emissions from coal combustion contribute approximately half of anthropogenic Hg emissions to the atmosphere. With the implementation of the first legally binding UNEP treaty aimed at reducing anthropogenic Hg emissions, the identification and traceability of Hg emissions from different countries/regions are critically important. Here, we present a comprehensive world coal Hg stable isotope database including 108 new coal samples from major coal-producing deposits in South Africa, China, Europe, India, Indonesia, Mongolia, former USSR, and the U.S. A 4.7‰ range in δ(202)Hg (-3.9 to 0.8‰) and a 1‰ range in Δ(199)Hg (-0.6 to 0.4‰) are observed. Fourteen (p coal Hg emissions tracing. A revised coal combustion Hg isotope fractionation model is presented, and suggests that gaseous elemental coal Hg emissions are enriched in the heavier Hg isotopes relative to oxidized forms of emitted Hg. The model explains to first order the published δ(202)Hg observations on near-field Hg deposition from a power plant and global scale atmospheric gaseous Hg. Yet, model uncertainties appear too large at present to permit straightforward Hg isotope source identification of atmospheric forms of Hg. Finally, global historical (1850-2008) coal Hg isotope emission curves were modeled and indicate modern-day mean δ(202)Hg and Δ(199)Hg values for bulk coal emissions of -1.2 ± 0.5‰ (1SD) and 0.05 ± 0.06‰ (1SD).

  9. Catalysts for cleaner combustion of coal, wood and briquettes sulfur dioxide reduction options for low emission sources

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.V. [Global Environmental Solutions, Inc., Morton Grove, IL (United States)

    1995-12-31

    Coal fired, low emission sources are a major factor in the air quality problems facing eastern European cities. These sources include: stoker-fired boilers which feed district heating systems and also meet local industrial steam demand, hand-fired boilers which provide heat for one building or a small group of buildings, and masonary tile stoves which heat individual rooms. Global Environmental Systems is marketing through Global Environmental Systems of Polane, Inc. catalysts to improve the combustion of coal, wood or fuel oils in these combustion systems. PCCL-II Combustion Catalysts promotes more complete combustion, reduces or eliminates slag formations, soot, corrosion and some air pollution emissions and is especially effective on high sulfur-high vanadium residual oils. Glo-Klen is a semi-dry powder continuous acting catalyst that is injected directly into the furnace of boilers by operating personnel. It is a multi-purpose catalyst that is a furnace combustion catalyst that saves fuel by increasing combustion efficiency, a cleaner of heat transfer surfaces that saves additional fuel by increasing the absorption of heat, a corrosion-inhibiting catalyst that reduces costly corrosion damage and an air pollution reducing catalyst that reduces air pollution type stack emissions. The reduction of sulfur dioxides from coal or oil-fired boilers of the hand fired stoker design and larger, can be controlled by the induction of the Glo-Klen combustion catalyst and either hydrated lime or pulverized limestone.

  10. Numerical simulation of pulverized coal combustion to reduce pollutants

    International Nuclear Information System (INIS)

    Mohammad Bagher Ayani; Behnam Rahmanian

    2010-01-01

    Full text: In this research, the numerical simulation of pollutant reduction and in a pulverized coal combustion at 2D combustion chamber have been studied. Finite volume method using structured grid arrangement was utilized for modeling the pulverized coal combustion. The pressure base algorithm and implicit solver has been employed to simulate non-premix combustion model. The air was diluted by some participative gaseous such as whose percentages varied from 0 % to 20 %. Participative gases and air were preheated by a high-temperature gas generator, and the preheated oxidizer temperature could achieve. The combustion simulation with the generalized finite rate chemistry model, referred to as the Magnussen model and the reacting flow with the mixture fraction PDF/ equilibrium chemistry model, referred to as the PDF model are studied. Quick scheme was adopted for the discretization of all convective terms of the advective transport equations. So, as a result of addition participative gases into oxidizer the rate of formation of pollutants as well as NO x suppressed. The addition only a few percent of halogen components can make some systems nonflammable. The effects of addition halogen components and non-reaction gaseous such as Helium and Argon are fuel dilution and its acts as catalysts in reducing the H atom concentration necessary for the chain branching reaction sequence. Moreover, they act like surface and they make the increment of surface ratio versus volume. Because of this, the number of radical conflicts and hence destruction them will be increase. Furthermore, the rate of formation of pollutants will be decreased if the halogen components and non-reaction gaseous injection will be increased. However, as a result of this research, in the case of injection in pulverized coal combustion the flame temperature is lower than Steam, Argon and Helium. So, the emission levels of carbon dioxide is significantly lower than other participative gases, but in this

  11. CFD simulation of thermodynamic and temperature effects on spontaneous combustion of coal stockpiles and dumps

    CSIR Research Space (South Africa)

    Kekana, J

    2011-01-01

    Full Text Available and energy conservation equations through the porous media. Combustion processes under consideration included physical absorption and desorption of atmospheric species in the coal matrix, formation of coal-oxygen complexes and oxygenated carbon species...

  12. Chemical analysis of solid residue from liquid and solid fuel combustion: Method development and validation

    Energy Technology Data Exchange (ETDEWEB)

    Trkmic, M. [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecturek Zagreb (Croatia); Curkovic, L. [University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb (Croatia); Asperger, D. [HEP-Proizvodnja, Thermal Power Plant Department, Zagreb (Croatia)

    2012-06-15

    This paper deals with the development and validation of methods for identifying the composition of solid residue after liquid and solid fuel combustion in thermal power plant furnaces. The methods were developed for energy dispersive X-ray fluorescence (EDXRF) spectrometer analysis. Due to the fuels used, the different composition and the location of creation of solid residue, it was necessary to develop two methods. The first method is used for identifying solid residue composition after fuel oil combustion (Method 1), while the second method is used for identifying solid residue composition after the combustion of solid fuels, i. e. coal (Method 2). Method calibration was performed on sets of 12 (Method 1) and 6 (Method 2) certified reference materials (CRM). CRMs and analysis test samples were prepared in pellet form using hydraulic press. For the purpose of method validation the linearity, accuracy, precision and specificity were determined, and the measurement uncertainty of methods for each analyte separately was assessed. The methods were applied in the analysis of real furnace residue samples. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    Data.gov (United States)

    U.S. Environmental Protection Agency — Pulverized bituminous coal was burned in a 10W externally heated entrained flow furnace under air-combustion and three oxy-combustion inlet oxygen conditions (28,...

  14. OxyFuel combustion of Coal and Biomass

    DEFF Research Database (Denmark)

    Toftegaard, Maja Bøg

    The power and heat producing sector is facing a continuously increasing demand to reduce its emissions of CO2. Oxyfuel combustion combined with CO2 storage is suggested as one of the possible, promising technologies which will enable the continuous use of the existing fleet of suspension-fired po......The power and heat producing sector is facing a continuously increasing demand to reduce its emissions of CO2. Oxyfuel combustion combined with CO2 storage is suggested as one of the possible, promising technologies which will enable the continuous use of the existing fleet of suspension......-fired power plants burning coal or other fuels during the period of transition to renewable energy sources. The oxyfuel combustion process introduces several changes to the power plant configuration. Most important, the main part of the flue gas is recirculated to the boiler and mixed with pure oxygen....... The oxidant thus contains little or no nitrogen and a near-pure CO2 stream can be produced by cooling the flue gas to remove water. The change to the oxidant composition compared to combustion in air will induce significant changes to the combustion process. This Ph.D. thesis presents experimental...

  15. Applying Rock Engineering Systems (RES approach to Evaluate and Classify the Coal Spontaneous Combustion Potential in Eastern Alborz Coal Mines

    Directory of Open Access Journals (Sweden)

    Amir Saffari

    2013-12-01

    Full Text Available Subject analysis of the potential of spontaneous combustion in coal layers with analytical and numerical methods has been always considered as a difficult task because of the complexity of the coal behavior and the number of factors influencing it. Empirical methods, due to accounting for certain and specific factors, have not accuracy and efficiency for all positions. The Rock Engineering Systems (RES approach as a systematic method for analyzing and classifying is proposed in engineering projects. The present study is concerned with employing the RES approach to categorize coal spontaneous combustion in coal regions. Using this approach, the interaction of parameters affecting each other in an equal scale on the coal spontaneous combustion was evaluated. The Intrinsic, geological and mining characteristics of coal seams were studied in order to identifying important parameters. Then, the main stages of implementation of the RES method i.e. interaction matrix formation, coding matrix and forming a list category were performed. Later, an index of Coal Spontaneous Combustion Potential (CSCPi was determined to format the mathematical equation. Then, the obtained data related to the intrinsic, geological and mining, and special index were calculated for each layer in the case study (Pashkalat coal region, Iran. So, the study offers a perfect and comprehensive classification of the layers. Finally, by using the event of spontaneous combustion occurred in Pashkalat coal region, an initial validation for this systematic approach in the study area was conducted, which suggested relatively good concordance in Pashkalat coal region.

  16. The effect of biomass on pollutant emission and burnout in co-combustion with coal

    Energy Technology Data Exchange (ETDEWEB)

    Kruczek, H.; Raczka, P.; Tatarek, A. [Wroclaw Technical University, Wroclaw (Poland)

    2006-08-15

    This paper presents experimental and numerical results on the co-combustion of different types of biomass with hard and brown coal. The main aim of this work was to assess the impact of the cocombustion of biomass in brown and hard coal-fired systems on the combustion process itself and on the level of pollutant formation and its dependence on combustion temperature stoichiometry. The experimental results obtained have shown that in general biomass addition leads to decreased NO and SO{sub 2} emissions, except with the hard coal Bogdanka. In addition, the biomass has a beneficial effect on the burnout of the coal/biomass mixture. To help to account for this effect, the behaviour of coal and biomass, the coal/biomass mixture and of fuel-N was studied by thermal analysis, in nitrogen and in air. The results obtained have shown that gas phase interactions are dominant in the combustion of biomass/coal mixtures.

  17. Thermo-optical properties of residential coals and combustion aerosols

    Science.gov (United States)

    Pintér, Máté; Ajtai, Tibor; Kiss-Albert, Gergely; Kiss, Diána; Utry, Noémi; Janovszky, Patrik; Palásti, Dávid; Smausz, Tomi; Kohut, Attila; Hopp, Béla; Galbács, Gábor; Kukovecz, Ákos; Kónya, Zoltán; Szabó, Gábor; Bozóki, Zoltán

    2018-04-01

    In this study, we present the inherent optical properties of carbonaceous aerosols generated from various coals (hard through bituminous to lignite) and their correlation with the thermochemical and energetic properties of the bulk coal samples. The nanoablation method provided a unique opportunity for the comprehensive investigation of the generated particles under well controlled laboratory circumstances. First, the wavelength dependent radiative features (optical absorption and scattering) and the size distribution (SD) of the generated particulate matter were measured in-situ in aerosol phase using in-house developed and customised state-of-the-art instrumentation. We also investigated the morphology and microstructure of the generated particles using Transmission Electron Microscopy (TEM) and Electron Diffraction (ED). The absorption spectra of the measured samples (quantified by Absorption Angström Exponent (AAE)) were observed to be distinctive. The correlation between the thermochemical features of bulk coal samples (fixed carbon (FC) to volatile matter (VM) ratio and calorific value (CV)) and the AAE of aerosol assembly were found to be (r2 = 0.97 and r2 = 0.97) respectively. Lignite was off the fitted curves in both cases most probably due to its high optically inactive volatile material content. Although more samples are necessary to be investigated to draw statistically relevant conclusion, the revealed correlation between CV and Single Scattering Albedo (SSA) implies that climatic impact of coal combusted aerosol could depend on the thermal and energetic properties of the bulk material.

  18. Kinetics of coal combustion: Part 3, Mechanisms and kinetics of char combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gavalas, G. R.; Flagan, R. C. [California Inst. of Tech., Pasadena, CA (USA)

    1988-09-01

    This report summarizes a three-year research program aimed at developing this level of understanding of char combustion through a combination of detailed analysis of chars as produced during devolatilization and as they evolve during oxidation, and theoretical studies of the porous microstructures and of pore diffusion and reaction within the coal particles. A small number of coals have been studied in detail, namely a HVA bituminous (PSOC 1451), a sub-bituminous (PSOC 1488), and a lignite (PSOC 1443). Chars have been generated from size-classified samples of these coals by pyrolysis in an inert atmosphere in a drop tube furnace. The chars were then characterized both chemically and physically. Subsequent oxidation studies were performed on these chars. 42 refs., 54 figs., 4 tabs.

  19. NO emission characteristics of superfine pulverized coal combustion in the O2/CO2 atmosphere

    International Nuclear Information System (INIS)

    Liu, Jiaxun; Gao, Shan; Jiang, Xiumin; Shen, Jun; Zhang, Hai

    2014-01-01

    Highlights: • Superfine pulverized coal combustion in O 2 /CO 2 atmosphere is a new promising technology. • NO emissions of superfine pulverized coal combustion in O 2 /CO 2 mixture were focused. • Coal particle sizes have significant effects on NO emissions in O 2 /CO 2 combustion. - Abstract: The combination of O 2 /CO 2 combustion and superfine pulverized coal combustion technology can make full use of their respective merits, and solve certain inherent disadvantages of each technology. The technology of superfine pulverized coal combustion in the O 2 /CO 2 atmosphere is easy and feasible to be retrofitted with few reconstructions on the existing devices. It will become a useful and promising method in the future. In this paper, a one-dimensional drop-tube furnace system was adopted to study the NO emission characteristics of superfine pulverized coal combustion in the O 2 /CO 2 atmosphere. The effects of coal particle size, coal quality, furnace temperature, stoichiometric ratio, etc. were analyzed. It is important to note that coal particle sizes have significant influence on NO emissions in the O 2 /CO 2 combustion. For the homogeneous NO reduction, smaller coal particles can inhibit the homogeneous NO formations under fuel-rich combustion conditions, while it becomes disadvantageous for fuel-lean combustion. However, under any conditions, heterogeneous reduction is always more significant for smaller coal particle sizes, which have smoother pore surfaces and simpler pore structures. The results from this fundamental research will provide technical support for better understanding and developing this new combustion process

  20. Numerical investigation of heat transfer characteristics in utility boilers of oxy-coal combustion

    International Nuclear Information System (INIS)

    Hu, Yukun; Li, Hailong; Yan, Jinyue

    2014-01-01

    Highlights: • Air-coal and oxy-coal combustion in an industrial scale PF boiler were simulated in ANSYS FLUENT. • The O 2 concentration of 33 vol% in the oxy-coal combustion case matches the air-coal combustion case most closely. • The moisture in the flue gas has little impact on flame temperature, but positive impact on surface incident radiation. - Abstract: Oxy-coal combustion has different flue gas composition from the conventional air-coal combustion. The different composition further results in different properties, such as the absorption coefficient, emissivity, and density, which can directly affect the heat transfer in both radiation and convection zones of utility boilers. This paper numerically studied a utility boiler of oxy-coal combustion and compares with air-coal combustion in terms of flame profile and heat transferred through boiler side walls in order to understand the effects of different operating conditions on oxy-coal boiler retrofitting and design. Based on the results, it was found that around 33 vol% of effective O 2 concentration ([O 2 ] effective ) the highest flame temperature and total heat transferred through boiler side walls in the oxy-coal combustion case match to those in the air-coal combustion case most; therefore, the 33 vol% of [O 2 ] effective could result in the minimal change for the oxy-coal combustion retrofitting of the existing boiler. In addition, the increase of the moisture content in the flue gas has little impact on the flame temperature, but results in a higher surface incident radiation on boiler side walls. The area of heat exchangers in the boiler was also investigated regarding retrofitting. If boiler operates under a higher [O 2 ] effective , to rebalance the load of each heat exchanger in the boiler, the feed water temperature after economizer can be reduced or part of superheating surfaces can be moved into the radiation zone to replace part of the evaporators

  1. Transformations of inorganic coal constituents in combustion systems

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J. (ed.); Srinivasachar, S.; Wilemski, G.; Boni, A.A. (PSI Technology Co., Andover, MA (United States)); Kang, Shim-Gyoo; Sarofim, A.F.; Graham, K.A.; Beer, J.M. (Massachusetts Inst. of Tech., Cambridge, MA (United States)); Peterson, T.W.; Wendt, O.L.; Gallagher, N.B.; Bool, L. (Arizona Univ., Tucson, AZ (United States)); Huggins, F.E.; Huffman, G.P.; Shah, N.; Shah, A. (Kentucky Univ., Lexington

    1992-11-01

    This report contains the computer codes developed for the coal combustion project. In Subsection B.1 the FORTRAN code developed for the percolative fragmentation model (or the discrete model, since a char is expressed as a collection of discrete elements in a discrete space) is presented. In Subsection B.2 the code for the continuum model (thus named because mineral inclusions are distributed in a continuum space) is presented. A stereological model code developed to obtain the pore size distribution from a two-dimensional data is presented in Subsection B.3.

  2. Catalytic Unmixed Combustion of Coal with Zero Pollution

    Energy Technology Data Exchange (ETDEWEB)

    George Rizeq; Parag Kulkarni; Raul Subia; Wei Wei

    2005-12-01

    GE Global Research is developing an innovative energy-based technology for coal combustion with high efficiency and near-zero pollution. This Unmixed Combustion of coal (UMC-Coal) technology simultaneously converts coal, steam and air into two separate streams of high pressure CO{sub 2}-rich gas for sequestration, and high-temperature, high-pressure vitiated air for producing electricity in gas turbine expanders. The UMC process utilizes an oxygen transfer material (OTM) and eliminates the need for an air separation unit (ASU) and a CO{sub 2} separation unit as compared to conventional gasification based processes. This is the final report for the two-year DOE-funded program (DE-FC26-03NT41842) on this technology that ended in September 30, 2005. The UMC technology development program encompassed lab- and pilot-scale studies to demonstrate the UMC concept. The chemical feasibility of the individual UMC steps was established via lab-scale testing. A pilot plant, designed in a related DOE funded program (DE-FC26-00FT40974), was reconstructed and operated to demonstrate the chemistry of UMC process in a pilot-scale system. The risks associated with this promising technology including cost, lifetime and durability OTM and the impact of contaminants on turbine performance are currently being addressed in detail in a related ongoing DOE funded program (DE-FC26-00FT40974, Phase II). Results obtained to date suggest that this technology has the potential to economically meet future efficiency and environmental performance goals.

  3. Temporal measurements and kinetics of selenium release during coal combustion and gasification in a fluidized bed

    International Nuclear Information System (INIS)

    Shen, Fenghua; Liu, Jing; Zhang, Zhen; Yang, Yingju

    2016-01-01

    Highlights: • The temporal release of Se from coal combustion and gasification was measured. • Kinetic laws for Se release from coal combustion and gasification were determined. • The influences of temperature and chemical composition of flue gas were clarified. • The interactions of Se species with mineral affect the release kinetics of Se. - Abstract: The temporal release of selenium from coal during combustion and gasification in a fluidized bed was measured in situ by an on-line analysis system of trace elements in flue gas. The on-line analysis system is based on an inductively coupled plasma optical emission spectroscopy (ICP-OES), and can measure concentrations of trace elements in flue gas quantitatively and continuously. The results of on-line analysis suggest that the concentration of selenium in flue gas during coal gasification is higher than that during coal combustion. Based on the results of on-line analysis, a second-order kinetic law r(x) = 0.94e −26.58/RT (−0.56 x 2 −0.51 x + 1.05) was determined for selenium release during coal combustion, and r(x) = 11.96e −45.03/RT (−0.53 x 2 −0.56 x + 1.09) for selenium release during coal gasification. These two kinetic laws can predict respectively the temporal release of selenium during coal combustion and gasification with an acceptable accuracy. Thermodynamic calculations were conducted to predict selenium species during coal combustion and gasification. The speciation of selenium in flue gas during coal combustion differs from that during coal gasification, indicating that selenium volatilization is different. The gaseous selenium species can react with CaO during coal combustion, but it is not likely to interact with mineral during coal gasification.

  4. Swelling kinetics of several residues from Shenhua coal extraction

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Mei-xia; Shui, Heng-fu; Wang, Zhi-cai [Anhui University of Technology, Maanshan (China). School of Chemistry and Chemical Engineering

    2008-08-15

    In order to understand the mechanism of swelling and the relation between swelling behavior and solvent extraction, the swelling kinetics of residues from Shenhua coal extracted by CS{sub 2}/NMP with different mixing ratios were studied in different solvents. The result shows that the swelling rates of extraction residues increase along with swelling temperature. The swelling rate in polar solvent NMP is much higher than that in non-polar solvent THN. Solvent extraction has a great effect on the swelling of extraction residues. The swelling activation energy of extraction residues increases and the swelling rate decreases with the increase of extraction yield. The swelling activation energies of extraction residues in NMP and THN are less than 10 kJ/mol, suggesting that the swelling process is controlled by solvent molecular diffusion in coal structure. 22 refs., 2 figs., 7 tabs.

  5. Influence of the hydrothermal dewatering on the combustion characteristics of Chinese low-rank coals

    International Nuclear Information System (INIS)

    Ge, Lichao; Zhang, Yanwei; Xu, Chang; Wang, Zhihua; Zhou, Junhu; Cen, Kefa

    2015-01-01

    This study investigates the influence of hydrothermal dewatering performed at different temperatures on the combustion characteristics of Chinese low-rank coals with different coalification maturities. It was found that the upgrading process significantly decreased the inherent moisture and oxygen content, increased the calorific value and fixed carbon content, and promoted the damage of the hydrophilic oxygen functional groups. The results of oxygen/carbon atomic ratio indicated that the upgrading process converted the low-rank coals near to high-rank coals which can also be gained using the Fourier transform infrared spectroscopy. The thermogravimetric analysis showed that the combustion processes of upgraded coals were delayed toward the high temperature region, and the upgraded coals had higher ignition and burnout temperature. On the other hand, based on the higher average combustion rate and comprehensive combustion parameter, the upgraded coals performed better compared with raw brown coals and the Da Tong bituminous coal. In ignition segment, the activation energy increased after treatment but decreased in the combustion stage. The changes in coal compositions, microstructure, rank, and combustion characteristics were more notable as the temperature in hydrothermal dewatering increased from 250 to 300 °C or coals of lower ranks were used. - Highlights: • Typical Chinese lignites with various ranks are upgraded by hydrothermal dewatering. • Upgraded coals exhibit chemical compositions comparable with that of bituminous coal. • FTIR show the change of microstructure and improvement in coal rank after upgrading. • Upgraded coals exhibit difficulty in ignition but combust easily. • More evident effects are obtained for raw brown coal with relative lower rank.

  6. Mercury emission, control and measurement from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Wei-Ping [North China Electric Power Univ., Beijing (China). School of Energy and Power Engineering; Western Kentucky Univ., Bowling Green, KY (United States). Inst. for Combustion Science and Environmental Technology; Cao, Yan [Western Kentucky Univ., Bowling Green, KY (United States). Inst. for Combustion Science and Environmental Technology; Zhang, Kai [North China Electric Power Univ., Beijing (China). School of Energy and Power Engineering

    2013-07-01

    Coal-fired electric power generation accounts for 65% of U.S. emissions of sulfur dioxide (SO2), 22% of nitrogen oxides (NOx), and 37% of mercury (Hg). The proposed Clear Air Interstate Rule (CAIR) and Clean Air Mercury Rule (CAMR) will attempt to regulate these emissions using a cap-and-trade program to replace a number of existing regulatory requirements that will impact this industry over the next decade. Mercury emissions remain the largest source that has not yet been efficiently controlled, in part because this is one of the most expensive to control. Mercury is a toxic, persistent pollutant that accumulates in the food chain. During the coal combustion process, when both sampling and accurate measurements are challenging, we know that mercury is present in three species: elemental, oxidized and particulate. There are three basic types of mercury measurement methods: Ontario Hydro Method, mercury continuous emission monitoring systems (CEMS) and sorbent-based monitoring. Particulate mercury is best captured by electrostatic precipitators (ESP). Oxidized mercury is best captured in wet scrubbers. Elemental mercury is the most difficult to capture, but selective catalytic reduction units (SCRs) are able to convert elemental mercury to oxidized mercury allowing it to be captured by wet flue gas desulfurization (FGD). This works well for eastern coals with high chlorine contents, but this does not work well on the Wyoming Powder River Basin (PRB) coals. However, no good explanation for its mechanism, correlations of chlorine content in coal with SCR performance, and impacts of higher chlorine content in coal on FGD re-emission are available. The combination of SCR and FGD affords more than an 80% reduction in mercury emissions in the case of high chlorine content coals. The mercury emission results from different coal ranks, boilers, and the air pollution control device (APCD) in power plant will be discussed. Based on this UAEPA new regulation, most power plants

  7. Cement production from coal conversion residues

    International Nuclear Information System (INIS)

    Brown, L.D.; Clavenna, L.R.; Eakman, J.M.; Nahas, N.C.

    1981-01-01

    Cement is produced by feeding residue solids containing carbonaceous material and ash constituents obtained from converting a carbonaceous feed material into liquids and/or gases into a cement-making zone and burning the carbon in the residue solids to supply at least a portion of the energy required to convert the solids into cement

  8. A Reduced Order Model for the Design of Oxy-Coal Combustion Systems

    Directory of Open Access Journals (Sweden)

    Steven L. Rowan

    2015-01-01

    Full Text Available Oxy-coal combustion is one of the more promising technologies currently under development for addressing the issues associated with greenhouse gas emissions from coal-fired power plants. Oxy-coal combustion involves combusting the coal fuel in mixtures of pure oxygen and recycled flue gas (RFG consisting of mainly carbon dioxide (CO2. As a consequence, many researchers and power plant designers have turned to CFD simulations for the study and design of new oxy-coal combustion power plants, as well as refitting existing air-coal combustion facilities to oxy-coal combustion operations. While CFD is a powerful tool that can provide a vast amount of information, the simulations themselves can be quite expensive in terms of computational resources and time investment. As a remedy, a reduced order model (ROM for oxy-coal combustion has been developed to supplement the CFD simulations. With this model, it is possible to quickly estimate the average outlet temperature of combustion flue gases given a known set of mass flow rates of fuel and oxidant entering the power plant boiler as well as determine the required reactor inlet mass flow rates for a desired outlet temperature. Several cases have been examined with this model. The results compare quite favorably to full CFD simulation results.

  9. 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...

  10. Combustion behaviour of Sydney and Bowen Basin coals determined by thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Benfell, K.E.; Beamish, B.B.; Rodgers, K.A.; Crosdale, P.J. [University of Auckland, Auckland (New Zealand). Department of Geology

    1996-08-01

    Assesses the suitability of thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis techniques to characterise the combustion behaviour of Sydney and Bowen basin coals. Results indicate that the thermogravimetric technique is suitable for characterising the effects of rank, maceral, sub-maceral and seam variations on the combustion behaviour of these coals. 6 refs., 6 figs., 2 tabs.

  11. Environmental indicators of the combustion of prospective coal water slurry containing petrochemicals.

    Science.gov (United States)

    Dmitrienko, Margarita A; Nyashina, Galina S; Strizhak, Pavel A

    2017-09-15

    Negative environmental impact of coal combustion has been known to humankind for a fairly long time. Sulfur and nitrogen oxides are considered the most dangerous anthropogenic emissions. A possible solution to this problem is replacing coal dust combustion with that of coal water slurry containing petrochemicals (CWSP). Coal processing wastes and used combustible liquids (oils, sludge, resins) are promising in terms of their economic and energy yield characteristics. However, no research has yet been conducted on the environmental indicators of fuels based on CWSP. The present work contains the findings of the research of CO, CO2, NOx, SOx emissions from the combustion of coals and CWSPs produced from coal processing waste (filter cakes). It is demonstrated for the first time that the concentrations of dangerous emissions from the combustion of CWSPs (carbon oxide and dioxide), even when combustible heavy liquid fractions are added, are not worse than those of coal. As for the concentration of sulfur and nitrogen oxides, it is significantly lower for CWSPs combustion as compared to coals. The presented research findings illustrate the prospects of the wide use of CWSPs as a fuel that is cheap and beneficial, in terms of both energy output and ecology, as compared to coal. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2017-01-01

    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 (CO 2 , H 2 O, 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. - Highlights: • A Monte Carlo–based nongray radiation solver is developed to study effects of radiation. • Radiation alters the lift-off height, and the distribution of temperature andspecies for the target flame. • Radiation alters the heat transfer mechanism of medium

  13. Influence of inorganic compounds on the combustion of coal. III. The effect of water of constitution of added compounds, moisture, and mineral matter in coal

    Energy Technology Data Exchange (ETDEWEB)

    Newall, H F

    1939-01-01

    The effects on the combustion rate from excess moisture and the addition of selected inorganic substances to powdered coals were determined. The catalytic effect of 19 known inorganic ash constituents on combustion rates was also examined. Alumina and silica were found to inhibit combustion while ferric oxide accelerated it. Titanium, Ge, and B oxides, along with gypsum and calcium phosphate, decreased the rate of combusion, while Ca, Mg, Mn, and V oxides increased combustion rates. Although several of the ash constituents in coal directly affected combustion rates, the effect of adding them to the coal prior to combustion did not correlate with the effect of the mineral matter already in the coal.

  14. The combustion of coal blends in a fluidised bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Boavida, Dulce; Abelha, Pedro; Gulyurtlu, Ibrahim; Cabrita, Isabel

    1999-07-01

    Combustion studies of five coals of different origin were carried out in a laboratory scale fluidised bed combustor. Five blends prepared by mixing two coals based on their petrological characterisation, in varying amounts, were selected to study the possibility of reduction NO{sub x}, N{sub 2}O and SO{sub 2} emissions. The results showed that some blends had the opposite behaviour concerning the release of NO{sub x} and SO{sub 2} in relation to parent coals, and the emissions were higher than expected. The N{sub 2}O amounts observed were, however, in almost all blends tested, lower than predicted values. With some blends, the mixing levels intended to reduce SO{sub 2} were not always found to correspond to those for simultaneous decrease of Nox. Most of the blends studied showed some evidence of interaction between them. Varying the proportion of the blend components was observed to alter the temperatures at which interactions were stronger.

  15. Co-combustion of waste with coal in a circulating fluidised bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Gulyurtlu, I.; Boavida, D.; Abelha, P.; Lopes, H.; Cabrita, I. [DEECA-INETI, Lisboa (Portugal)

    2002-07-01

    The results of a study of cocombustion of waste with coal is described. Various wastes (biomass, sludge, and refuse derived fuel) were burned with coal in a circulating fluidised bed combustor. Conditions that prevent segregated combustion, reduce production of nitrogen oxides, and attain high combustion efficiency were studied. The effects of variations in air staging in the riser, mixing of air with volatiles, coal/biomass ratio, methods of feeding biomass, and temperature are described. 5 refs., 3 figs., 5 tabs.

  16. Low temperature oxidation and spontaneous combustion characteristics of upgraded low rank coal

    Energy Technology Data Exchange (ETDEWEB)

    Choi, H.K.; Kim, S.D.; Yoo, J.H.; Chun, D.H.; Rhim, Y.J.; Lee, S.H. [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2013-07-01

    The low temperature oxidation and spontaneous combustion characteristics of dried coal produced from low rank coal using the upgraded brown coal (UBC) process were investigated. To this end, proximate properties, crossing-point temperature (CPT), and isothermal oxidation characteristics of the coal were analyzed. The isothermal oxidation characteristics were estimated by considering the formation rates of CO and CO{sub 2} at low temperatures. The upgraded low rank coal had higher heating values than the raw coal. It also had less susceptibility to low temperature oxidation and spontaneous combustion. This seemed to result from the coating of the asphalt on the surface of the coal, which suppressed the active functional groups from reacting with oxygen in the air. The increasing upgrading pressure negatively affected the low temperature oxidation and spontaneous combustion.

  17. Recent advances in the use of synchrotron radiation for the analysis of coal combustion products

    Energy Technology Data Exchange (ETDEWEB)

    Manowitz, B. [Brookhaven National Lab., Upton, NY (United States)

    1995-11-01

    Two major coal combustion problems are the formation and build-up of slag deposits on heat transfer surfaces and the production and control of toxic species in coal combustion emissions. The use of synchrotron radiation for the analysis of coal combustion products can play a role in the better understanding of both these phenomena. An understanding of the chemical composition of such slags under boiler operating conditions and as a function of the mineral composition of various coals is one ultimate goal of this program. The principal constituents in the ash of many coals are the oxides of Si, Al, Fe, Ca, K, S, and Na. The analytical method required must be able to determine the functional forms of all these elements both in coal and in coal ash at elevated temperatures. One unique way of conducting these analyses is by x-ray spectroscopy.

  18. Combustion reactivity of chars from copyrolysis of coal with coke-oven gas

    Energy Technology Data Exchange (ETDEWEB)

    Liao Hongqiang; Sun Chenggong; Li Baoqing [Chinese Academy of Sciences, Taiyuan (China). State Key Lab. of Coal Conversion

    1997-12-31

    The combustion reactivity of char from pyrolysis of Xianfeng lignite with coke-oven gas (COG) is related to the pyrolysis pressure and heating rate. Decreasing pressure and increasing heating rate enhance the char yields and combustion reactivity. The combustion reactivities of char from coal pyrolysis with COG nearly reach to that of char from hydropyrolysis, but lower than those of char from coal pyrolysis under N{sub 2}. (orig.)

  19. Co-combustion of low rank coal/waste biomass blends using dry air or oxygen

    International Nuclear Information System (INIS)

    Haykiri-Acma, H.; Yaman, S.; Kucukbayrak, S.

    2013-01-01

    Biomass species such as the rice husk and the olive milling residue, and a low quality Turkish coal, Soma Denis lignite, were burned in a thermal analyzer under pure oxygen and dry air up to 900 °C, and differential thermal analysis (DTA) and derivative thermogravimetric (DTG) analysis profiles were obtained. Co-combustion experiments of lignite/biomass blends containing 5–20 wt% of biomass were also performed. The effects of the oxidizer type and the blending ratio of biomass were evaluated considering some thermal reactivity indicators such as the maximum burning rate and its temperature, the maximum heat flow temperature, and the burnout levels. FTIR (Fourier transform infrared) spectroscopy and SEM (scanning electron microscopy) were used to characterize the samples, and the variations in the combustion characteristics of the samples were interpreted based on the differences in the intrinsic properties of the samples. - Highlights: ► Co-combustion of lignite/biomass blends. ► The effects of the oxidizer type and the blending ratio. ► Effects of intrinsic properties on combustion characteristics.

  20. Numerical investigation for combustion characteristics of vacuum residue (VR) in a test furnace

    International Nuclear Information System (INIS)

    Sreedhara, S.; Huh, Kang Y.; Park, Hoyoung

    2007-01-01

    It has become inevitable to search for alternative fuels due to current worldwide energy crisis. In this paper combustion characteristics of vacuum residue (VR) is investigated numerically against experimental data in typical operating conditions of a furnace. Heat release reaction is modeled as sequential steps of devolatilization, simplified gas phase reaction and char oxidation as for pulverized coal. Thermal and fuel NO are predicted by the conditional moment closure (CMC) method for estimation of elementary reaction rates. It turns out that Sauter mean diameter (SMD) of VR droplets is a crucial parameter for better combustion efficiency and lower NO. Reasonable agreement is achieved for spatial distributions of major species, temperature and NO for all test cases with different fuel and steam flow rates

  1. Volcanic ash in feed coal and its influence on coal combustion products

    Energy Technology Data Exchange (ETDEWEB)

    Brownfield, M.E.; Affolter, R.H.; Cathcart, J.D.; Brownfield, I.K.; Hower, J.C.; Stricker, G.D.; O' Connor, J.T.

    2000-07-01

    The US Geological Survey and the University of Kentucky Center for Applied Energy Research are collaborating with an Indiana Utility to determine the physical and chemical properties of feed coal and coal combustion products (CCPs) from a coal-fired power plant. The plant utilizes a low-sulfur (.23--.47 weight percent S) coal from the Powder River Basin, Wyoming. Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) analysis of feed coal samples identified two mineral suites. A primary suite (not authigenic) consisting of quartz (detrital and volcanic beta-form grains), biotite, and minor zircon and a secondary authigenic mineral suite containing calcite, alumino-phosphates (crandallite and gorceixite), kaolinite, quartz, anatase, barite, and pyrite. The authigenic minerals are attributed to air-fall and reworked volcanic ash that was deposited in peat-forming mires. The Powder River Basin feed coals contain higher amounts of Ba, Ca, Mg, Na, Sr, and P compared to other analyzed eastern coals. These elements are associated with alumino-phosphate, biotite, calcite, and clay minerals. The element associations are indicative of coal that incorporated volcanic ash during deposition. XRD analysis of CCPs revealed a predominance of glass, perovskite, lime, gehlenite, quartz, and phosphates with minor amounts of periclase, anhydrite, hematite, and spinel group minerals in the fly ash; and quartz, plagioclase (albite and anorthite), pyroxene (augite and fassaite), rhodonite, and akermanite in the bottom ash. Microprobe and SEM analysis of fly ash samples revealed quartz, zircon, monazite, euhedral laths of corundum with merrillite, hematite, dendritic spinels/ferrites, and rounded grains of wollastonite with periclase. The abundant Ca and Mg mineral phases in the fly ashes are related to the presence of carbonate, clay, and phosphate minerals in the feed coal. The Ca- and Mg-rich mineral phases in the CCPs can be attributed to volcanic minerals deposited in the

  2. Dioxin emissions from coal combustion in domestic stove: Formation in the chimney and coal chlorine content influence

    Directory of Open Access Journals (Sweden)

    Paradiz Bostjan

    2015-01-01

    Full Text Available Combustion experiments conducted in domestic stove burning hard coal demonstrated a predominant influence of the coal chlorine content on the PCDD/F emissions, together with a pronounced effect of the flue gas temperature. PCDD/F concentrations of over 100 ng TEQ/m3, three orders of magnitude higher than in a modern waste incinerator, were measured in the flue gases of a domestic stove when combusting high chlorine coal (0.31 %. The PCDD/F concentrations in the flue gases dropped below 0,5 ng TEQ/m3, when low chlorine coal (0.07 % was used. When low chlorine coal was impregnated with NaCl to obtain 0.38 % chlorine content, the emission of the PCDD/Fs increased by two orders of magnitude. Pronounced nonlinearity of the PCDD/F concentrations related to chlorine content in the coal was observed. The combustion of the high chlorine coal yielded PCDD/F concentrations in flue gases one order of magnitude lower in a fan cooled chimney when compared to an insulated one, thus indicating formation in the chimney. The influence of flue gas temperature on the PCDD/F emissions was less pronounced when burning low chlorine coal. The predominant pathway of the PCDD/F emissions is via flue gases, 99 % of the TEQ in the case of the high chlorine coal for insulated chimney.

  3. Decrease of noxious emissions in the residual fuel oil combustion; Disminucion de emisiones nocivas en la combustion de aceite combustible residual

    Energy Technology Data Exchange (ETDEWEB)

    Mandoki W, Jorge [Econergia S. de R. L. de C. V. Mexico, D. F. (Mexico)

    1994-12-31

    The residual fuel oil combustion emits noxious substances such as carbonaceous particulate, nitrogen oxides, and sulfur trioxide at unacceptable levels. Water emulsified in the fuel substantially reduces such emissions, achieving besides, in most of the cases, a net saving in the fuel consumption. The beneficial effects are shown in burning the residual fuel oil as a water emulsion, as well as the method to produce an adequate emulsion. The emulsified fuel technology offers a low cost option to reduce air pollution. The fuel oil quality has been declining during the last decades due to: 1. Increase in the production of crude heavy oils, generally with higher content of asphaltens and sulfur. 2. Less availability of vacuum distillation residues due to its conversion into greater value products. 3. More intensive conversion processes such as catalytic cracking, visbreaking, etc. that increase the asphaltenes concentration in the bottoms, causing instability problems. 4. The increase in the vanadium and other metals content as the concentration of asphaltenes increases. The use of emulsified fuel oil provides an efficient and economical method to substantially reduce the noxious emissions to the atmosphere. The emulsion contains water particles in a diameter between 2 and 20 microns, uniformly distributed in the fuel oil, generally in a proportion generally of 5 to 10%; besides, it contains a tensioactive agent to assure a stable emulsion capable of withstanding the shearing forces of the pumping and distribution systems. When the atomized oil drops get into the combustion chamber, the emulsified water flashes into high pressure steam, originating a violent secondary atomization. The effect of this secondary atomization is the rupture of the oil drops of various hundred microns, producing drops of 5 to 15 microns in diameter. Since the necessary time for combustion is an exponential function of the drop diameter, a very substantial improvement in the combustion is

  4. Monitoring temperatures in coal conversion and combustion processes via ultrasound

    Science.gov (United States)

    Gopalsami, N.; Raptis, A. C.; Mulcahey, T. P.

    1980-02-01

    The state of the art of instrumentation for monitoring temperatures in coal conversion and combustion systems is examined. The instrumentation types studied include thermocouples, radiation pyrometers, and acoustical thermometers. The capabilities and limitations of each type are reviewed. A feasibility study of the ultrasonic thermometry is described. A mathematical model of a pulse-echo ultrasonic temperature measurement system is developed using linear system theory. The mathematical model lends itself to the adaptation of generalized correlation techniques for the estimation of propagation delays. Computer simulations are made to test the efficacy of the signal processing techniques for noise-free as well as noisy signals. Based on the theoretical study, acoustic techniques to measure temperature in reactors and combustors are feasible.

  5. Combustion Characteristics Of Agricultural Waste-Coal Char Blends

    International Nuclear Information System (INIS)

    Akpabio, I. O; Danbature W

    2002-01-01

    Shortage of petroleum products, depletion of huge forest reserves for fuel purposes with its attendant erosion problems and other environmental considerations have necessitated investigations into other sources of fuel. In this wise. a set of seven types of briquettes were prepared from agricultural wastes such as rice husk, maize husk and saw-dust and blends of carbonized coal char. Strong and well-formed briquettes with good combustion characteristics were obtained. The results obtained from water boiling tests show that 2 litres of water could be boiled just under 23 minutes. Moisture contents and strengths of these briquettes were also determined and are discussed. The results show that wastes could be converted into useful fuel

  6. Studies of MHD generator performance with oxygen enriched coal combustion

    Science.gov (United States)

    Wormhoudt, J.; Yousefian, V.; Kolb, C. E.; Martinez-Sanchez, M.

    1980-07-01

    This paper presents calculations made using the Aerodyne PACKAGE (Plasma Analysis, Chemical Kinetics, and Generator Efficiency) computer code which bear on two questions which arise in connection with choices between oxygen enrichment and air preheating to attain the high combustion temperatures needed for open-cycle, coal-fired MHD power generation. The first question is which method produces the highest enthalpy extraction per unit channel length. The second is, in test facilities intended to study tradeoffs between oxygen enrichment and preheated air, can good generator performance be obtained from the same physical channel for different combustor compositions. The answer to the first question is found to depend on what combustor conditions are taken to be comparable. As for the second question, it is found that operation with channel input from off-design combustor conditions can cause serious problems, which can be partially alleviated by changing the channel load factors.

  7. Preparation and combustion of coal-water fuel from the Sin Pun coal deposit, southern Thailand

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    In response to an inquiry by the Department of Mineral Resources in Thailand, the Energy & Environmental Research Center (EERC) prepared a program to assess the responsiveness of Sin Pun lignite to the temperature and pressure conditions of hot-water drying. The results indicate that drying made several improvements in the coal, notably increases in heating value and carbon content and reductions in equilibrium moisture and oxygen content. The equilibrium moisture content decreased from 27 wt% for the raw coal to about 15 wt% for the hot-water-dried (HWD) coals. The energy density for a pumpable coal-water fuel (CWF) indicates an increase from 4500 to 6100 Btu/lb by hot-water drying. Approximately 650 lb of HWD Sin Pun CWF were fired in the EERC`s combustion test facility. The fuel burned extremely well, with no feed problems noted during the course of the test. Fouling and slagging deposits each indicated a very low rate of ash deposition, with only a dusty layer formed on the cooled metal surfaces. The combustor was operated at between 20% and 25% excess air, resulting in a flue gas SO{sub 2} concentration averaging approximately 6500 parts per million.

  8. Characterization of products of combustion of mineral coal

    International Nuclear Information System (INIS)

    Pinheiro, H.S.; Albuquerque, J. S. V.; Sales, J.C.; Nogueira, R.E.F.Q.

    2011-01-01

    During the burning of coal in power plants, various types of waste or by products are generated. These materials have been the subject of several studies. They contain ashes and have many technological applications, such as in the production of various types of ceramic pieces. The objective of this work was to study the feasibility of adding the coal combustion products as filler for ceramics. X-ray fluorescence analysis was used to identify and quantify the proportions of the elements contained in the sample and x-ray diffraction to identify the phases present. The analysis by X-ray diffraction revealed a diffraction pattern of silicon sulfide, calcium silicate and sulfide phases of Aluminium, Potassium and Titanium. X-ray fluorescence analysis showed silica (37.14%), calcium (21.86%), aluminum (14.69%) and sulfur (8.70%). These results show characteristics of materials with potential for incorporation in ceramic bodies, provided that some processing is done to eliminate the sulfur. (author)

  9. UTILIZATION OF LOW NOx COAL COMBUSTION BY-PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    J.Y. Hwang; X. Huang; M.G. McKimpson; R.E. Tieder; A.M. Hein; J.M. Gillis; D.C. Popko; K.L. Paxton; Z. Li; X. Liu; X. Song; R.I. Kramer

    1998-12-01

    Low NO{sub x} combustion practices are critical for reducing NO{sub x} emissions from power plants. These low NO{sub x} combustion practices, however, generate high residual carbon contents in the fly ash produced. These high carbon contents threaten utilization of this combustion by-product. This research has successfully developed a separation technology to render fly ash into useful, quality-controlled materials. This technology offers great flexibility and has been shown to be applicable to all of the fly ashes tested (more than 10). The separated materials can be utilized in traditional fly ash applications, such as cement and concrete, as well as in nontraditional applications such as plastic fillers, metal matrix composites, refractories, and carbon adsorbents. Technologies to use beneficiated fly ash in these applications are being successfully developed. In the future, we will continue to refine the separation and utilization technologies to expand the utilization of fly ash. The disposal of more than 31 million tons of fly ash per year is an important environmental issue. With continued development, it will be possible to increase economic, energy and environmental benefits by re-directing more of this fly ash into useful materials.

  10. Chemical characterization of bottom ashes generated during combustion of a Colombian mineral coal in a thermal power plant

    International Nuclear Information System (INIS)

    Pinheiro, H.S.; Nogueira, R.E.F.Q.; Lobo, C.J.S.; Nobre, A.I.S.; Sales, J.C.; Silva, C.J.M.

    2012-01-01

    Bottom ashes generated during combustion of a mineral coal from Colombia were characterized by X-ray fluorescence spectrometry and X-ray diffraction. The interest in this particular coal is due to the fact that it will be used by a thermal power plant in Ceara, Northeastern Brazil, where it could produce over 900 tons of different residues/combustion products every day. Results from Xray fluorescence allowed identification and quantification of elements present in the sample: silicon (59,17%), aluminum (13,17%), iron (10,74%), potassium (6,11%), titanium (2,91%), calcium (4,97%), sulphur (0,84%) and others (2,09%). The X-ray diffraction revealed patterns from silica, mullite, calcium sulphate and hydrated sodium. Results obtained so far indicate that the material is a potential raw-material for use in the formulation of ceramic components (author)

  11. Mercury emissions from coal combustion in Silesia, analysis using geostatistics

    Science.gov (United States)

    Zasina, Damian; Zawadzki, Jaroslaw

    2015-04-01

    Data provided by the UNEP's report on mercury [1] shows that solid fuel combustion in significant source of mercury emission to air. Silesia, located in southwestern Poland, is notably affected by mercury emission due to being one of the most industrialized Polish regions: the place of coal mining, production of metals, stone mining, mineral quarrying and chemical industry. Moreover, Silesia is the region with high population density. People are exposed to severe risk of mercury emitted from both: industrial and domestic sources (i.e. small household furnaces). Small sources have significant contribution to total emission of mercury. Official and statistical analysis, including prepared for international purposes [2] did not provide data about spatial distribution of the mercury emitted to air, however number of analysis on Polish public power and energy sector had been prepared so far [3; 4]. The distribution of locations exposed for mercury emission from small domestic sources is interesting matter merging information from various sources: statistical, economical and environmental. This paper presents geostatistical approach to distibution of mercury emission from coal combustion. Analysed data organized in 2 independent levels: individual, bottom-up approach derived from national emission reporting system [5; 6] and top down - regional data calculated basing on official statistics [7]. Analysis, that will be presented, will include comparison of spatial distributions of mercury emission using data derived from sources mentioned above. Investigation will include three voivodeships of Poland: Lower Silesian, Opole (voivodeship) and Silesian using selected geostatistical methodologies including ordinary kriging [8]. References [1] UNEP. Global Mercury Assessment 2013: Sources, Emissions, Releases and Environmental Transport. UNEP Chemicals Branch, Geneva, Switzerland, 2013. [2] NCEM. Poland's Informative Inventory Report 2014. NCEM at the IEP-NRI, 2014. http

  12. Carbon and oxygen isotopic composition of coal and carbon dioxide derived from laboratory coal combustion: A preliminary study

    Science.gov (United States)

    Warwick, Peter D.; Ruppert, Leslie F.

    2016-01-01

    The concentration of carbon dioxide (CO2) in the atmosphere has dramatically increased from the start of the industrial revolution in the mid-1700s to present levels exceeding 400 ppm. Carbon dioxide derived from fossil fuel combustion is a greenhouse gas and a major contributor to on-going climate change. Carbon and oxygen stable isotope geochemistry is a useful tool to help model and predict the contributions of anthropogenic sources of CO2 in the global carbon cycle. Surprisingly few studies have addressed the carbon and oxygen isotopic composition of CO2 derived from coal combustion. The goal of this study is to document the relationships between the carbon and oxygen isotope signatures of coal and signatures of the CO2 produced from laboratory coal combustion in atmospheric conditions.Six coal samples were selected that represent various geologic ages (Carboniferous to Tertiary) and coal ranks (lignite to bituminous). Duplicate splits of the six coal samples were ignited and partially combusted in the laboratory at atmospheric conditions. The resulting coal-combustion gases were collected and the molecular composition of the collected gases and isotopic analyses of δ13C of CO2, δ13C of CH4, and δ18O of CO2 were analysed by a commercial laboratory. Splits (~ 1 g) of the un-combusted dried ground coal samples were analyzed for δ13C and δ18O by the U.S. Geological Survey Reston Stable Isotope Laboratory.The major findings of this preliminary work indicate that the isotopic signatures of δ13C (relative to the Vienna Pee Dee Belemnite scale, VPDB) of CO2 resulting from coal combustion are similar to the δ13CVPDB signature of the bulk coal (− 28.46 to − 23.86 ‰) and are not similar to atmospheric δ13CVPDB of CO2 (~ − 8 ‰, see http://www.esrl.noaa.gov/gmd/outreach/isotopes/c13tellsus.html). The δ18O values of bulk coal are strongly correlated to the coal dry ash yields and appear to have little or no influence on the δ18O values of CO2

  13. Aqueous clay suspensions stabilized by alginate fluid gels for coal spontaneous combustion prevention and control.

    Science.gov (United States)

    Qin, Botao; Ma, Dong; Li, Fanglei; Li, Yong

    2017-11-01

    We have developed aqueous clay suspensions stabilized by alginate fluid gels (AFG) for coal spontaneous combustion prevention and control. Specially, this study aimed to characterize the effect of AFG on the microstructure, static and dynamic stability, and coal fire inhibition performances of the prepared AFG-stabilized clay suspensions. Compared with aqueous clay suspensions, the AFG-stabilized clay suspensions manifest high static and dynamic stability, which can be ascribed to the formation of a robust three-dimensional gel network by AFG. The coal acceleration oxidation experimental results show that the prepared AFG-stabilized clay suspensions can improve the coal thermal stability and effectively inhibit the coal spontaneous oxidation process by increasing crossing point temperature (CPT) and reducing CO emission. The prepared low-cost and nontoxic AFG-stabilized clay suspensions, exhibiting excellent coal fire extinguishing performances, indicate great application potentials in coal spontaneous combustion prevention and control.

  14. A comparison of spontaneous combustion susceptibility of coal from ...

    African Journals Online (AJOL)

    Although the CPT of Onyeama coal and Owukpa coal is identical to each other as they are the sub-bituminous, Owukpa coal has a lower initial oxidation temperature (IOT) and maximum oxidation temperature (MOT) than those of Onyeama coal. This means that although each coal has the same rank and CPT, spontaneous ...

  15. Low temperature combustion of organic coal-water fuel droplets containing petrochemicals while soaring in a combustion chamber model

    Directory of Open Access Journals (Sweden)

    Valiullin Timur R.

    2017-01-01

    Full Text Available The paper examines the integral characteristics (minimum temperature, ignition delay times of stable combustion initiation of organic coal-water fuel droplets (initial radius is 0.3-1.5 mm in the oxidizer flow (the temperature and velocity varied in ranges 500-900 K, 0.5-3 m/s. The main components of organic coal-water fuel were: brown coal particles, filter-cakes obtained in coal processing, waste engine, and turbine oils. The different modes of soaring and ignition of organic coal-water fuel have been established. The conditions have been set under which it is possible to implement the sustainable soaring and ignition of organic coal-water fuel droplets. We have compared the ignition characteristics with those defined in the traditional approach (based on placing the droplets on a low-inertia thermocouple junction into the combustion chamber. The paper shows the scale of the influence of heat sink over the thermocouple junction on ignition inertia. An original technique for releasing organic coal-water fuel droplets to the combustion chamber was proposed and tested. The limitations of this technique and the prospects of experimental results for the optimization of energy equipment operation were also formulated.

  16. Thermogravimetric Analysis of Textile Dyeing Sludge (TDS) in N₂/CO₂/O₂ Atmospheres and its Combustion Model with Coal.

    Science.gov (United States)

    Zhuo, Zhongxu; Liu, Jingyong; Sun, Shuiyu; Kuo, Jiahong; Sun, Jian; Chang, Ken-Lin; Fu, Jiewen

    2018-01-01

      The combustion characteristics of textile dyeing sludge (TDS) in N2/O2, CO2/O2, and N2/CO2 atmospheres, and blends of TDS with coal were analyzed using TGA (thermogravimetric analysis). Results showed that the replacement of N2 by CO2 resulted in negative effects on the combustion and pyrolysis of TDS. Comparing N2/O2 and CO2/O2 atmospheres, combustion of TDS was easier in a N2/O2 atmosphere, but the residual mass after TDS pyrolysis in pure CO2 was less than that in N2 by approximately 4.51%. When the proportion of TDS was 30-50% in the blends of coal with TDS, a synergistic interaction clearly occurred, and it significantly promoted combustion. In considering different combustion parameters, the optimal proportion of TDS may be between 20-30%. The activation energy Ea value decreased from 155.6 kJ/mol to 53.35 kJ/mol with an increasing TDS proportion from 0% to 50%, and it rapidly decreased when the TDS proportion was below 20%.

  17. Effect of coal blending on the leaching characteristics of arsenic and selenium in fly ash from fluidized bed coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, F.; Yamada, N.; Sato, A.; Ninomiya, Yoshihiko [Chubu Univ., Aichi (Japan). Dept. of Applied Chemistry; Zhang, L. [Monash Univ., Clayton, VIC (Australia). Dept. of Chemical Engineering

    2013-07-01

    The capture ability of fly ash to arsenic (As) and selenium (Se) was investigated through the combustion of two single bituminous coals A and B and their mixture (blending ratio of 1:1, wt/wt) in a lab-scale fluidized bed reactor. The leaching characteristics of As and Se in corresponding fly ash were also conducted according to Japanese Industrial Standard (JIS). Speciation of As and Se during fly ash leaching test were predicted from the perspective of thermodynamic equilibrium. The results indicate that, combustion of coal B, containing abundant calcium, possesses a higher capture ability of As and Se than that of coal A through possible chemical reaction between As/Se with CaO. Leaching behavior of As and Se from fly ash is strongly dependent on the pH of the leachate. Free calcium in fly ash generates an alkaline leachate during leaching test and subsequently reduces As and Se leaching, which cause the leaching ratio of As and Se in fly ash derived from the combustion of coal B was much lower, relative to that in coal A. Combustion of blending coal promotes the overall capture ability of the fly ash to As/Se and reduces their leaching from fly ash through the synergy of free CaO between this two kind of fly ash.

  18. Coal char combustion under a CO{sub 2}-rich atmosphere: Implications for pulverized coal injection in a blast furnace

    Energy Technology Data Exchange (ETDEWEB)

    Borrego, A.G.; Casal, M.D. [Instituto Nacional del Carbon, CSIC. P.O. Box 73, 33080 Oviedo (Spain); Osorio, E.; Vilela, A.C.F. [Laboratorio de Siderurgia, DEMET/PPGEM - Universidade Federal do Rio Grande do Sul. P.O. Box 15021, 91501-970 Porto Alegre (Brazil)

    2008-11-15

    Pulverized coal injection (PCI) is employed in blast furnace tuyeres attempting to maximize the injection rate without increasing the amount of unburned char inside the stack of the blast furnace. When coal is injected with air through the injection lance, the resolidified char will burn in an atmosphere with a progressively lower oxygen content and higher CO{sub 2} concentration. In this study an experimental approach was followed to separate the combustion process into two distinct devolatilization and combustion steps. Initially coal was injected into a drop tube furnace (DTF) operating at 1300 C in an atmosphere with a low oxygen concentration to ensure the combustion of volatiles and prevent the formation of soot. Then the char was refired into the DTF at the same temperature under two different atmospheres O{sub 2}/N{sub 2} (typical combustion) and O{sub 2}/CO{sub 2} (oxy-combustion) with the same oxygen concentration. Coal injection was also performed under a higher oxygen concentration in atmospheres typical for both combustion and oxy-combustion. The fuels tested comprised a petroleum coke and coals currently used for PCI injection ranging from high volatile to low volatile bituminous rank. Thermogravimetric analyses and microscopy techniques were used to establish the reactivity and appearance of the chars. Overall similar burnouts were achieved with N{sub 2} and CO{sub 2} for similar oxygen concentrations and therefore no loss in burnout should be expected as a result of enrichment in CO{sub 2} in the blast furnace gas. The advantage of increasing the amount of oxygen in a reacting atmosphere during burnout was found to be greater, the higher the rank of the coal. (author)

  19. CO-COMBUSTION OF REFUSE DERIVED FUEL WITH COAL IN A FLUIDISED BED COMBUSTOR

    Directory of Open Access Journals (Sweden)

    W. A. WAN AB KARIM GHANI

    2009-03-01

    Full Text Available Power generation from biomass is an attractive technology which utilizes municipal solid waste-based refused derived fuel. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from refuse derived fuel was co-fired with coal in a 0.15 m diameter and 2.3 m high fluidized bed combustor. The combustion efficiency and carbon monoxide emissions were studied and compared with those from pure coal combustion. This study proved that the blending effect had increased the carbon combustion efficiency up to 12% as compared to single MSW-based RDF. Carbon monoxide levels fluctuated between 200-1600 ppm were observed when coal is added. It is evident from this research that efficient co-firing of biomass with coal can be achieved with minimum modification of existing coal-fired boilers.

  20. Three-dimensional simulation of flow and combustion for pulverised coal injection

    Energy Technology Data Exchange (ETDEWEB)

    Guo, B.Y.; Zulli, P.; Rogers, H.; Mathieson, J.G.; Yu, A.B. [BlueScope Steel Research, Port Kembla, NSW (Australia)

    2005-07-01

    A three-dimensional numerical model of pulverised coal injection has been developed for simulating coal flow and combustion in the tuyere and raceway of a blast furnace. The model has been used to simulate previously reported combustion tests, which feature an inclined co-axial lance with an annular cooling gas. The predicted coal burnout agrees well with that measured for three coals with volatile contents and particle size ranging between 20.2-36.4% and particle sizes 1-200 {mu}m. Many important phenomena including flow asymmetry, recirculating flow and particle dispersion in the combustion chamber have been predicted. The current model can reproduce the experimental observations including the effects on burnout of coal flowrate and the introduction of methane for lance cooling.

  1. Effect of resinite on the combustion of New Zealand subbituminous coal

    Energy Technology Data Exchange (ETDEWEB)

    Benfell, K.E.; Beamish, B.B.; Rodgers, K.A. [University of Newcastle, Callaghan, NSW (Australia). Dept. of Geology

    1997-09-01

    This paper shows that Oligocene resin from New Zealand`s Rotowaro coalfield displays DTA and DTG traces similar to those of other fossil resins. It modifies the thermal behaviour of low rank coal raising the peak combustion temperature and lowering its rate of combustion; this behaviour may be common among liptinite macerals. The effect is not additive and unlike other coal constituents the resinite component does not deteriorate with time.

  2. Inhibition Effect of Phosphorus Flame Retardants on the Fire Disasters Induced by Spontaneous Combustion of Coal

    Directory of Open Access Journals (Sweden)

    Yibo Tang

    2017-01-01

    Full Text Available Coal spontaneous combustion (CSC generally induces fire disasters in underground mines, thus causing serious casualties, environmental pollution, and property loss around the world. By using six P-containing additives to process three typical coal samples, this study investigated the variations of the self-ignition characteristics of the coal samples before and after treatment. The analysis was performed by combining thermogravimetric analysis/differential scanning calorimetry (TG/DSC Fourier transform infrared spectrometer (FTIR and low temperature oxidation. Experimental results showed that P-containing inhibitors could effectively restrain the heat emitted in the combustion of coal samples and therefore the ignition temperature of the coal samples was delayed at varying degrees. The combustion rate of the coal samples was reduced as well. At the temperatures ranging from 50°C to 150°C, the activation energy of the coal samples after the treatment was found to increase, which indicated that the coal samples were more difficult to be oxidized. After being treated with phosphorus flame retardants (PFRs, the content of several active groups represented by the C-O structure in the three coal samples was proved to be obviously changed. This suggested that PFRs could significantly inhibit the content of CO generated by the low temperature oxidation of coal, and the flame-retardant efficiency grew with the increasing temperature. At 200°C, the maximal inhibition efficiency reached approximately 85%.

  3. Two-stage catalytic up-grading of vacuum residue of a Wandoan coal liquid. [Vacuum residue of coal liquid

    Energy Technology Data Exchange (ETDEWEB)

    Mochida, I.; Sakanishi, K.; Korai, Y.; Fujitsu, H.

    1986-08-01

    A successive two-stage hydrotreatment using a commercial Ni-Mo/Al/sub 2/O/sub 3/ catalyst (HDN-30) was applied to the vacuum residue of a Wandoan coal liquid to achieve high levels of hydrocracking, hydrodenitrogenation and hydrodeoxygenation. Two-stage hydrotreatment in 1-methylnaphthalene containing 20wt% fluoranthene as a solvent at solvent/coal liquid ratio of unity removed 83% (overall) of nitrogen and 90% (overall) of oxygen in the asphaltene (benzene-soluble fraction) at 380/sup 0/C for 3 h and at 420/sup 0/C for 3h under hydrogen pressure of 15 MPa and 14 MPa, respectively, while the single stage treatment at 420/sup 0/C for 3 h removed only 41% and 46%, respectively. The same two-stage treatment allowed the overall denitrogenation of 51% and the overall deoxygenation of 67% from a mixture of asphaltene and preasphaltene (THF-soluble fraction). Addition of the catalyst prior to the second stage reaction increased the removal of nitrogen and oxygen to 75 and 82%, respectively, indicating significant catalyst deactivation by the preasphaltene fraction in the first stage. Increasing the solvent/coal liquid ratio to 2 or addition of tetrahydrofluoranthene as a component of the solvent increased the removal of nitrogen and oxygen to 70 and 80%, respectively. Such two-stage hydrotreatment was also effective in refining the whole residue, allowing denitrogenations and deoxygenations of 68 and 75% respectively using tetrahydrofluoranthene. The coke, unreacted coal and minerals in the residue may not cause acute catalyst deactivation. High dissolving ability of the reaction solvents is very effective to decrease catalyst deactivation by carbon deposition. The successive two-stage hydrotreatment also enhanced hydrocracking of polar and resin fractions in the residue into oils (conversion, 65%). (Abstract Truncated)

  4. Predictions of the impurities in the CO2 stream of an oxy-coal combustion plant

    International Nuclear Information System (INIS)

    Liu, Hao; Shao, Yingjuan

    2010-01-01

    Whilst all three main carbon capture technologies (post-combustion, pre-combustion and oxy-fuel combustion) can produce a CO 2 dominant stream, other impurities are expected to be present in the CO 2 stream. The impurities in the CO 2 stream can adversely affect other processes of the carbon capture and storage (CCS) chain including the purification, compression, transportation and storage of the CO 2 stream. Both the nature and the concentrations of potential impurities expected to be present in the CO 2 stream of a CCS-integrated power plant depend on not only the type of the power plant but also the carbon capture method used. The present paper focuses on the predictions of impurities expected to be present in the CO 2 stream of an oxy-coal combustion plant. The main gaseous impurities of the CO 2 stream of oxy-coal combustion are N 2 /Ar, O 2 and H 2 O. Even the air ingress to the boiler and its auxiliaries is small enough to be neglected, the N 2 /Ar concentration of the CO 2 stream can vary between ca. 1% and 6%, mainly depending on the O 2 purity of the air separation unit, and the O 2 concentration can vary between ca. 3% and 5%, mainly depending on the combustion stoichiometry of the boiler. The H 2 O concentration of the CO 2 stream can vary from ca. 10% to over 40%, mainly depending on the fuel moisture and the partitioning of recycling flue gas (RFG) between wet-RFG and dry-RFG. NO x and SO 2 are the two main polluting impurities of the CO 2 stream of an oxy-coal combustion plant and their concentrations are expected to be well above those found in the flue gas of an air-coal combustion plant. The concentration of NO x in the flue gas of an oxy-coal combustion plant can be up to ca. two times to that of an equivalent air-coal combustion plant. The amount of NO x emitted by the oxy-coal combustion plant, however, is expected to be much smaller than that of the air-coal combustion plant. The reductions of the recirculated NO x within the combustion

  5. Unconventional Coal in Wyoming: IGCC and Gasification of Direct Coal Liquefaction Residue

    Science.gov (United States)

    Schaffers, William Clemens

    Two unconventional uses for Wyoming Powder River Basin coal were investigated in this study. The first was the use of coal fired integrated gasification combined cycle (IGCC) plants to generate electricity. Twenty-eight different scenarios were modeled using AspenPlusRTM software. These included slurry, mechanical and dried fed gasifiers; Wyodak and Green River coals, 0%, 70%, and 90% CO2 capture; and conventional evaporative vs air cooling. All of the models were constructed on a feed basis of 6,900 tons of coal per day on an "as received basis". The AspenPlus RTM results were then used to create economic models using Microsoft RTM Excel for each configuration. These models assumed a 3 year construction period and a 30 year plant life. Results for capital and operating costs, yearly income, and internal rates of return (IRR) were compared. In addition, the scenarios were evaluated to compare electricity sales prices required to obtain a 12% IRR and to determine the effects of a carbon emissions tax on the sales price. The second part of the study investigated the gasification potential of residue remaining from solvent extraction or liquefaction of Powder River Basin Coal. Coal samples from the Decker mine on the Wyoming-Montana border were extracted with tetralin at a temperature of 360°C and pressure of 250 psi. Residue from the extraction was gasified with CO2 or steam at 833°C, 900°C and 975°C at pressures of 0.1 and 0.4 MPa. Product gases were analyzed with a mass spectrometer. Results were used to determine activation energies, reaction order, reaction rates and diffusion effects. Surface area and electron microscopic analyses were also performed on char produced from the solvent extraction residue.

  6. Development and testing of synthetic riprap constructed from coal combustion products (CCPs).

    Science.gov (United States)

    2014-07-01

    Even with an increase in the amount of coal combustion products (CCPs) used in concrete con-struction, soil stabilization, and other : applications, the coal power industry must dispose of a sig-nificant amount of fly ash and bottom ash. One potentia...

  7. Comparative study of two co-combustion concepts for sewage sludge in coal dust furnaces; Vergleich zweier Mitverbrennungskonzepte fuer Klaerschlamm in Kohlestaubfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Spliethoff, H.; Gerhardt, T.; Ruediger, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    1996-12-31

    Processes for thermal use of sewage sludge in coal dust furnaces were investigated at the Institute of Chemical Engineering and Boiler Technology (IVD) of Stuttgart university. Direct co-combustion of sewage sludge in coal dust furnaces is a simple concept, but it is useful provided that co-combustion has no negative effects in terms of performance, emissions and residue disposal. Externally dried sewage sludge has a residual water content in the same range as coal dust. The effects of co-combustion are discussed, and the experimentally determined effect in terms of emissions and residues is presented. Pyrolysis of the sewage sludge and use of the resulting gas as a reduction agent for denitrification may reduce negative effects of co-combustion on performance, emissions and residues.(orig) [Deutsch] Am Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart werden an Versuchsanlagen verschiedene Verfahren zur thermischen Nutzung von Klaerschlaemmen in Verbindung mit Kohlenstaufeuerungen untersucht. Die direkte Mitverbrennung von Klaerschlamm in Kohlestaubfeuerungen ist ein einfaches Konzept, das dann sinnvoll ist, wenn die Mitverbrennung keine negativen Auswirkungen auf Betrieb, Emissionen und Verwertung der Rueckstaende mit sich bringt. Bei einer externen Trockung weist der Klaerschlamm einen aehnlichen Wassergehalt wie der Auslegungsbrennstoff von Steinkohlenstaubfeuerungen auf. Die moeglichen Auswirkungen der Mitverbrennung von Klaerschlamm werden diskutiert und der im Versuch ermittelte Einfluss auf Emissionen und Reststoffe vogestellt. Durch Vorschaltung einer Pyrolyse des Klaerschlamms und Nutzung des erzeugten Gases als Reduktionsmittel zur Entsticklung kann die Auswirkung der Mitverbrennung auf Betrieb, Emissionen und Reststoffe der Feuerungsanlage vermindert werden. (orig)

  8. Comparative study of two co-combustion concepts for sewage sludge in coal dust furnaces; Vergleich zweier Mitverbrennungskonzepte fuer Klaerschlamm in Kohlestaubfeuerungen

    Energy Technology Data Exchange (ETDEWEB)

    Spliethoff, H; Gerhardt, T; Ruediger, H; Hein, K R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    1997-12-31

    Processes for thermal use of sewage sludge in coal dust furnaces were investigated at the Institute of Chemical Engineering and Boiler Technology (IVD) of Stuttgart university. Direct co-combustion of sewage sludge in coal dust furnaces is a simple concept, but it is useful provided that co-combustion has no negative effects in terms of performance, emissions and residue disposal. Externally dried sewage sludge has a residual water content in the same range as coal dust. The effects of co-combustion are discussed, and the experimentally determined effect in terms of emissions and residues is presented. Pyrolysis of the sewage sludge and use of the resulting gas as a reduction agent for denitrification may reduce negative effects of co-combustion on performance, emissions and residues.(orig) [Deutsch] Am Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart werden an Versuchsanlagen verschiedene Verfahren zur thermischen Nutzung von Klaerschlaemmen in Verbindung mit Kohlenstaufeuerungen untersucht. Die direkte Mitverbrennung von Klaerschlamm in Kohlestaubfeuerungen ist ein einfaches Konzept, das dann sinnvoll ist, wenn die Mitverbrennung keine negativen Auswirkungen auf Betrieb, Emissionen und Verwertung der Rueckstaende mit sich bringt. Bei einer externen Trockung weist der Klaerschlamm einen aehnlichen Wassergehalt wie der Auslegungsbrennstoff von Steinkohlenstaubfeuerungen auf. Die moeglichen Auswirkungen der Mitverbrennung von Klaerschlamm werden diskutiert und der im Versuch ermittelte Einfluss auf Emissionen und Reststoffe vogestellt. Durch Vorschaltung einer Pyrolyse des Klaerschlamms und Nutzung des erzeugten Gases als Reduktionsmittel zur Entsticklung kann die Auswirkung der Mitverbrennung auf Betrieb, Emissionen und Reststoffe der Feuerungsanlage vermindert werden. (orig)

  9. Influence of Environmentally Friendly and High-Efficiency Composite Additives on Pulverized Coal Combustion in Cement Industry

    Directory of Open Access Journals (Sweden)

    Zhiyong Wang

    2016-01-01

    Full Text Available 4 kinds of chemical reagents and 3 kinds of industrial wastes were selected as burning additives for 2 kinds of coals in cement industry. The work focused on the replacement of partial chemical reagents by industrial wastes, which not only reduced the cost and took full advantage of industrial wastes, but also guaranteed the high combustion efficiency and removed the NOX and SO2 simultaneously. The experiments were carried out in DTF. The combustion residues were analyzed by SEM and XRD. The results showed that the burnout rate was increased after adding the additives; meanwhile, the NOX and SO2 release concentration were reduced, but the degree of action varied for different additives and coals. The substitute of chemical reagents by industrial wastes was very effective; overall, the cold-rolled iron oxide worked better than others; the particles surface was tougher and the peaks of crystalline phase were lower than raw coal, which indicated that the additives played good roles in combustion process.

  10. DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    Harold H. Schobert; M. Mercedes Maroto-Valer; Zhe Lu

    2003-09-30

    The increasing role of coal as a source of energy in the 21st century will demand environmental and cost-effective strategies for the use of coal combustion by-products (CCBPs), mainly unburned carbon in fly ash. Unburned carbon is nowadays regarded as a waste product and its fate is mainly disposal, due to the present lack of efficient routes for its utilization. However, unburned carbon is a potential precursor for the production of adsorbent carbons, since it has gone through a devolatilization process while in the combustor, and therefore, only requires to be activated. Accordingly, the principal objective of this work was to characterize and utilize the unburned carbon in fly ash for the production of activated carbons. The unburned carbon samples were collected from different combustion systems, including pulverized utility boilers, a utility cyclone, a stoker, and a fluidized bed combustor. LOI (loss-on-ignition), proximate, ultimate, and petrographic analyses were conducted, and the surface areas of the samples were characterized by N2 adsorption isotherms at 77K. The LOIs of the unburned carbon samples varied between 21.79-84.52%. The proximate analyses showed that all the samples had very low moisture contents (0.17 to 3.39 wt %), while the volatile matter contents varied between 0.45 to 24.82 wt%. The elemental analyses show that all the unburned carbon samples consist mainly of carbon with very little hydrogen, nitrogen, sulfur and oxygen In addition, the potential use of unburned carbon as precursor for activated carbon (AC) was investigated. Activated carbons with specific surface area up to 1075m{sup 2}/g were produced from the unburned carbon. The porosity of the resultant activated carbons was related to the properties of the unburned carbon feedstock and the activation conditions used. It was found that not all the unburned carbon samples are equally suited for activation, and furthermore, their potential as activated carbons precursors could be

  11. Analysis of oxy-fuel combustion power cycle utilizing a pressurized coal combustor

    OpenAIRE

    Gazzino, Marco; Hong, Jongsup; Chaudhry, Gunaranjan; Brisson II, John G; Field, Randall; Ghoniem, Ahmed F

    2009-01-01

    Growing concerns over greenhouse gas emissions have driven extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology in which fuels are burned in an environment of oxygen and recycled combustion gases. In this paper, an oxy-fuel combustion power cycle that utilizes a pressurized coal combustor is analyzed. We show that this approach recovers more thermal energy from the flue gases...

  12. Good news to use from the environmental front: coal combustion products as an environmental success story

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.N. [ISG Resources, Inc., Salt Lake City, UT (United States)

    2002-07-01

    ISG Resources in the USA's largest manager and marketer of coal combustion products, involved also in developing new technologies and applications for treatment and use of fly ash, bottom ash, boiler slag and FGD by-products. The paper, outlined in a series of 14 overheads, describes the USA's successes and initiatives so far in coal combustion products utilization. Further opportunities for the coal industry were discussed. The industry is encouraged to become involved now in carbon trading mechanisms for fly ash utilization displacing cement production.

  13. Using X-ray methods to evaluate the combustion sulfur minerals and graphitic carbon in coals and ashes

    International Nuclear Information System (INIS)

    Wertz, D.L.; Collins, L.W.

    1988-01-01

    Coals are complex mixtures of vastly different materials whose combustion kinetics may well exhibit symbiotic effects. Although the sulfur oxide gases produced during the combustion of coals may have a variety of sources, they are frequently caused by the thermal degradation of inorganic minerals to produce ''acid rain''. Since many of the minerals involved either as reactants or products in coal combustion produce well defined x-ray power diffraction (XRPD) patterns, the fate of these minerals may be followed by measuring the XRPD patterns of combustion products. Coal 1368P, a coal with an unusually high pyrite (FeS/sub 2/) fraction, has been the subject materials in our investigations of the fate of the inorganic minerals during combustion. These studies include measuring the fate of pyrite and of graphitic carbon in coal 1368P under varying combustion conditions. The results discussed in this paper were obtained by standard XRPD methods

  14. Fluidized bed combustion of low-grade coal and wastes: Research and development

    Energy Technology Data Exchange (ETDEWEB)

    Borodulya, V.A.; Dikalenko, V.I.; Palchonok, G.I.; Vinogradov, L.M. [Academy of Sciences of Belarus, Minsk (Belarus). A.V. Luikov Heat and Mass Transfer Inst.; Dobkin, S.M.; Telegin, E.M. [Special Design Office, Brest (Belarus)

    1994-12-31

    Experimental studies were carried out to investigate devolatilization of fuel as single spherical particles of wood, hydrolytic lignin, leather sewage sludge and Belarussian brown coals in a fluidized bed of sand. It is found that the devolatilization process depends on moisture and ash contents in fuel and on the external heat and mass transfer rate. The char combustion occurs largely in the intermediate region. Kinetic parameters of the devolatilization and char combustion are obtained. A low-capacity fluidized bed boiler suitable for combustion of coal and different wastes is described.

  15. Air toxic emissions from the combustion of coal: Identifying and quantifying hazardous air pollutants from US coals

    Energy Technology Data Exchange (ETDEWEB)

    Szpunar, C.B.

    1992-09-01

    This report addresses the key air toxic emissions likely to emanate from continued and expanded use of domestic coal. It identifies and quantifies those trace elements specified in the US 1990 Clean Air Act Amendments, by tabulating selected characterization data on various source coals by region, state, and rank. On the basis of measurements by various researchers, this report also identifies those organic compounds likely to be derived from the coal combustion process (although their formation is highly dependent on specific boiler configurations and operating conditions).

  16. Air toxic emissions from the combustion of coal: Identifying and quantifying hazardous air pollutants from US coals

    International Nuclear Information System (INIS)

    Szpunar, C.B.

    1992-09-01

    This report addresses the key air toxic emissions likely to emanate from continued and expanded use of domestic coal. It identifies and quantifies those trace elements specified in the US 1990 Clean Air Act Amendments, by tabulating selected characterization data on various source coals by region, state, and rank. On the basis of measurements by various researchers, this report also identifies those organic compounds likely to be derived from the coal combustion process (although their formation is highly dependent on specific boiler configurations and operating conditions)

  17. Assessment of the content of arsenic in solid by-products from coal combustion

    Directory of Open Access Journals (Sweden)

    Wierońska Faustyna

    2017-01-01

    Full Text Available The coal combustion processes constitute one of the major sources of heavy metals emission into the atmosphere. From the point of view of the reduction of the emission of heavy metals and the selection of the correct exhaust gas treatment system, it is important to monitor the amount of trace elements in the solid fuels and in the solid by-products from coal combustion. One of these highly toxic elements is arsenic. The average content of arsenic in Polish hard coals and lignites is 0 ÷ 40 mg/kg [1] and 5 ÷ 15 mg/kg [2], respectively. The world average content of arsenic in hard coals and lignites, is equal to 9.0 ± 0.8 and 7.4 ± 1.4 mg/kg [3], respectively. During coal combustion processes, a significant amount of arsenic enters the atmosphere through gases and fly ashes. The proportions in which those two forms of arsenic occur in exhaust gases depend on the conditions of combustion processes [4]. The aim of the research was to determine the content of arsenic in coal blends and by-products of their combustion (slag, fly ash, gypsum, filter cakes. The determination of the arsenic quantity was performed using the Atomic Absorption Spectrometry with the electrothermal atomization.

  18. Determination of properties of clean coal technology post-process residue

    Directory of Open Access Journals (Sweden)

    Agnieszka Klupa

    2016-01-01

    Full Text Available This article presents the possibilities of using modern measuring devices to determine the properties of process residues (Polish acronym: UPP. UPP was taken from the combustion process from a power plant in Silesia. Determining the properties of UPP is the basis for making decisions about its practical application, for example, as a raw material to obtain useful products such as: pozzolan, cenosphere or zeolite, for which there is demand. The development of advanced technology and science has given rise to modern and precise research tools that contribute to the development of appropriate methods to assess the properties of post-process residue. For this study the following were used: scanning electron microscope with EDS microanalysis and an analyzer for particle size-, shape- and number- analysis. The study conducted confirms the effectiveness of SEM analysis to determine the properties of post-process residue from Clean Coal Technologies (CCT. The results obtained are an introduction to further research on the determination of properties of CCT post-process residue. Research to determine the properties of CCT post-process residue only began relatively recently.

  19. Release of nitrogen precursors from coal and biomass residues in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    P. Abelha; I. Gulyurtlu; I. Cabrita [Instituto Nacional de Engenharia, Lisbon (Portugal)

    2008-01-15

    This work was undertaken with the aim of quantifying the relative amounts of NH{sub 3} and HCN released from different residues during their devolatilization under fluidized bed conditions. The results were compared with data collected for bituminous coals of different origin. The relation between amounts of HCN and NH{sub 3} released and the levels of NOX and N{sub 2}O formed during cocombustion was also addressed. The partitioning of nitrogen between volatiles and char was also quantified. The pyrolysis studies were undertaken in a small fluidized bed reactor of 80 mm of ID and 500 mm high using an inert atmosphere (N{sub 2}). The HCN and NH{sub 3} were quantified by bubbling the pyrolysis gases in absorbing solutions which were subsequently analyzed with selective electrodes. The combustion studies were carried out on a pilot installation. The fluidized bed combustor is square in cross section with each side being 300 mm long. There is secondary air supply to the freeboard at different heights to deal with high volatile fuels as almost all waste materials are. The temperatures in the bed and in the freeboard and that of the flue gases leaving the reactor were continuously monitored. The results obtained suggest that, while coal releases nitrogen mostly as HCN, residues like RDF and sewage sludge give out fuel-N in greater quantities as NH{sub 3}. Residues at fluidized bed combustion (FBC) temperatures release more than 80% of the fuel-N with the volatiles. The NH{sub 3} evolved during pyrolysis acted as a reducing agent on NOX emissions. The presence of calcium significantly reduces the emission of N{sub 2}O probably by interfering with HCN chemistry. With high amounts of residues in the fuel mixture, the relative importance of char on the nitrogen chemistry substantially decreases. By using cocombustion, it is possible to reduce fuel-N conversion to NOX and N{sub 2}O, by tuning the amounts of coal and residue in the mixture. 29 refs., 18 figs., 3 tabs.

  20. Prevention of trace and major element leaching from coal combustion products by hydrothermally-treated coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Adnadjevic, B.; Popovic, A.; Mikasinovic, B. [University of Belgrade, Belgrade (Serbia). Dept. of Chemistry

    2009-07-01

    The most important structural components of coal ash obtained by coal combustion in 'Nikola Tesla A' power plant located near Belgrade (Serbia) are amorphous alumosilicate, alpha-quartz, and mullite. The phase composition of coal ash can be altered to obtain zeolite type NaA that crystallizes in a narrow crystallization field (SiO{sub 2}/Al{sub 2}O{sub 3}; Na{sub 2}O/SiO{sub 2}; H{sub 2}O/Na{sub 2}O ratios). Basic properties (crystallization degree, chemical composition, the energy of activation) of obtained zeolites were established. Coal ash extracts treated with obtained ion-exchange material showed that zeolites obtained from coal ash were able to reduce the amounts of iron, chromium, nickel, zinc, copper, lead, and manganese in ash extracts, thus proving its potential in preventing pollution from dump effluent waters.

  1. Characteristics of fundamental combustion and NOx emission using various rank coals.

    Science.gov (United States)

    Kim, Sung Su; Kang, Youn Suk; Lee, Hyun Dong; Kim, Jae-Kwan; Hong, Sung Chang

    2011-03-01

    Eight types of coals of different rank were selected and their fundamental combustion characteristics were examined along with the conversion of volatile nitrogen (N) to nitrogen oxides (NOx)/fuel N to NOx. The activation energy, onset temperature, and burnout temperature were obtained from the differential thermogravimetry curve and Arrhenius plot, which were derived through thermo-gravimetric analysis. In addition, to derive the combustion of volatile N to NOx/fuel N to NOx, the coal sample, which was pretreated at various temperatures, was burned, and the results were compared with previously derived fundamental combustion characteristics. The authors' experimental results confirmed that coal rank was highly correlated with the combustion of volatile N to NOx/fuel N to NOx.

  2. Dew point of flue gas in the combustion of brown coal briquettes

    Energy Technology Data Exchange (ETDEWEB)

    Schinkel, W

    1977-08-01

    Economical operation of small steam generators can follow two courses, viz. to channel the emitted gases through the plant and reduce waste gas loss. Two possibilities exist to achieve this: firstly a steam generating process with only slight excess air; secondly a reduction of the emitted gas temperature. The lowest waste gas temperature found in sulphur-containing combustion materials is measured by finding the acid dew-point of the waste gas. The following results in the case of brown coal briquettes were found. Measurements of the dew point of flue gas in two steam generators, both of the double flue type, one having a capacity of 12.5 t/h, the other 25 t/h, one using brown coal briquettes with 1% sulphur content, the other with 3%, resulted in the fact that the dew point can be measured. It was shown that a low air ratio leads to a lowering of the dew point. However this process is unfortunately economically unviable in chain grate generators as the waste gas becomes so thin under a high air ratio that the dew point can only be minimally reduced. Further the acid dew point is only slightly influenced by partial operation of the generator and the infusion of briquette residue.

  3. Zinc isotopic composition of particulate matter generated during the combustion of coal and coal + tire-derived fuels

    Science.gov (United States)

    Borrok, D.M.; Gieré, R.; Ren, M.; Landa, E.R.

    2010-01-01

    Atmospheric Zn emissions from the burning of coal and tire-derived fuel (TDF) for power generation can be considerable. In an effort to lay the foundation for tracking these contributions, we evaluated the Zn isotopes of coal, a mixture of 95 wt % coal + 5 wt % TDF, and the particulate matter (PM) derived from their combustion in a power-generating plant. The average Zn concentrations and δ(66)Zn were 36 mg/kg and 183 mg/kg and +0.24‰ and +0.13‰ for the coal and coal + TDF, respectively. The δ(66)Zn of the PM sequestered in the cyclone-type mechanical separator was the lightest measured, -0.48‰ for coal and -0.81‰ for coal+TDF. The δ(66)Zn of the PM from the electrostatic precipitator showed a slight enrichment in the heavier Zn isotopes relative to the starting material. PM collected from the stack had the heaviest δ(66)Zn in the system, +0.63‰ and +0.50‰ for the coal and coal + TDF, respectively. Initial fractionation during the generation of a Zn-rich vapor is followed by temperature-dependent fractionation as Zn condenses onto the PM. The isotopic changes of the two fuel types are similar, suggesting that their inherent chemical differences have only a secondary impact on the isotopic fractionation process.

  4. Thermal effects from the release of selenium from a coal combustion during high-temperature processing: a review.

    Science.gov (United States)

    Hu, Jianjun; Sun, Qiang; He, Huan

    2018-04-11

    The release of selenium (Se) during coal combustion can have serious impacts on the ecological environment and human health. Therefore, it is very important to study the factors that concern the release of Se from coal combustion. In this paper, the characteristics of the release of Se from coal combustion, pyrolysis, and gasification of different coal species under different conditions are studied. The results show that the amount of released Se increases at higher combustion temperatures. There are obvious increases in the amount of released Se especially in the temperature range of 300 to 800 °C. In addition, more Se is released from the coal gasification than coal combustion process, but more Se is released from coal combustion than pyrolysis. The type of coal, rate of heating, type of mineral ions, and combustion atmosphere have different effects on the released percentage of Se. Therefore, having a good understanding of the factors that surround the release of Se during coal combustion, and then establishing the combustion conditions can reduce the impacts of this toxic element to humans and the environment.

  5. Evaluation of coal combustion byproducts as soil liming materials - their influence on soil pH and enzyme activities

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, G W; Siddaramappa, R; Wright, R J; Codling, E E; Gao, G

    1994-03-01

    To evaluate coal combustion byproducts as liming materials and address issues related to soil quality, the authors compared the influence of different amounts of four combustion byproducts (fly ash and bed ash from a fluidized bed combustion furnace, lime-injected multistage burner residue, and spray dryer residue) and CaCO[sub 3] on soil pH and activities of urease, phosphatase, arylsulfatase, and dehydrogenase in an acidic soil. Studies comparing the influence of the combustion byproducts and CaCO[sub 3] on soil pH showed that on weight basis of application, substantial differences were observed in the ability of these materials to influence soil pH but that such differences decreased markedly after the data were transformed to a CaCO[sub 3] equivalent basis of application. Analysis of covariance for these transformed data indicated that whereas the liming abilities of fly ash and CaCO[sub 3] were not significantly different when compared on the CaCO[sub 3] equivalent basis, those of bed ash, multistage burner residue, and spray dryer residue were less than that of CaCO[sub 3]. Studies comparing the influence of the byproducts and CaCO[sub 3] on soil enzyme activities showed that the effect of these liming materials on the enzyme activities studied was largely due to their influence on soil pH. These studies showed that the combustion byproducts tested functioned as soil liming materials in a manner similar to that of CaCO[sub 3] and seemed to have little adverse effect on soil quality.

  6. Production of Indigenous and Enriched Khyber Pakhtunkhwa Coal Briquettes: Combustion and Disintegration Strength Analysis

    International Nuclear Information System (INIS)

    Habib, M.; Khan, A.U.; Habib, U.; Memon, A.R.

    2013-01-01

    Khyber Pakhtun Khwa province of Pakistan has considerable amounts of low ranked coal. However, due to the absence of any centrally administered power generation system there is a need to explore indigenous methods for effectively using this valuable energy resource. In the present study an indigenous coal briquetting technology has been developed and evaluated in terms of combustion characteristics such as moisture content, volatile matter, ash, fixed carbon and calorific value of the resulting coal briquette and disintegration strength using polyvinyl acetate (PVA) in combination with calcium carbonate (sample no 3 with highest disintegration strength value of 2059N). Comparison of test samples with the commercially available coal briquettes revealed improved combustion characteristics for the PVA bonded (sample no 1 and 5) coal briquettes having higher fixed carbon content and calorific value, lower ash contents as well as lower initial ignition time. (author)

  7. Production of Indigenous and Enriched Khyber Pakhtunkhwa Coal Briquettes: Combustion and Disintegration Strength Analysis

    Directory of Open Access Journals (Sweden)

    Unsia Habib

    2013-06-01

    Full Text Available Khyber Pakhtun Khwa province of Pakistan has considerable amounts of low ranked coal. However, due to the absence of any centrally administered power generation system there is a need to explore indigenous methods for effectively using this valuable energy resource. In the present study an indigenous coal briquetting technology has been developed and evaluated in terms of combustion characteristics such as moisture content, volatile matter, ash, fixed carbon and calorific value of the resulting coal briquette and disintegration strength using polyvinyl acetate (PVA in combination with calcium carbonate (sample no 3 with highest disintegration strength value of 2059N. Comparison of test samples with the commercially available coal briquettes revealed improved combustion characteristics for the PVA bonded (sample no 1 and 5 coal briquettes having higher fixed carbon content and calorific value, lower ash contents as well as lower initial ignition time.

  8. Boron availability to plants from coal combustion by-products

    International Nuclear Information System (INIS)

    Kukier, U.; Sumner, M.E.

    1996-01-01

    Agronomic use of coal combustion by-products is often associated with boron (B) excess in amended soils and subsequently in plants. A greenhouse study with corn (Zea mays L.) as test plant was conducted to determine safe application rates of five fly ashes and one flue gas desulfurization gypsum (FDG). All by-products increased soil and corn tissue B concentration, in some cases above toxicity levels which are 5 mg hot water soluble B (hwsB)kg -1 soil and 100 mg B kg -1 in corn tissue. Acceptable application rates varied from 4 to 100 Mg ha -1 for different by-products. Leaching and weathering of a high B fly ash under ponding conditions decreased its B content and that of corn grown in fly ash amended soil, while leaching of the same fly ash under laboratory conditions increased fly ash B availability to corn in comparison to the fresh fly ash. Hot water soluble B in fly ash or FDG amended soil correlated very well with corn tissue B. Hot water soluble B in fly ash amended soil could be predicted based on soil pH and B solubility in ash at different pH values but not so in the case of FDG. Another greenhouse study was conducted to compare the influence of FDG and Ca(OH 2 ) on B concentration in spinach (Spinacia oleracea L.) leaves grown in soil amended with the high B fly ash. The Ca(OH) 2 significantly decreased tissue B content, while FDG did not affect B uptake from fly ash amended soil. 41 refs., 6 figs., 5 tabs

  9. Disposal of coal combustion wastes in the hydraulic backfill process

    Science.gov (United States)

    Pierzyna, Piotr

    2017-11-01

    This article presents the results of studies regarding the physical properties of selected combustion by-products (CCPs) currently produced in the energy production industry. These properties have been compared with the requirements of the technologies applied in the Polish underground mines. The article gives special consideration to the application of the products in the hydraulic backfill technology. The possibility of using bottom-ashes and slags was considered. The amount of CCPs disposed in Polish hard coal mines is approximately 1.1 million Mg and the tendency is decreasing. In the past two years, approximately 100-150 thousand Mg of CCPs was used in the hydraulic backfill technology. The percentage of the fraction smaller than 0.1 mm is determining for the possibility of using a given type of CCPs in the backfill material. This practically excludes the possibility of using any fly ashes in that technology. In slags from conventional boilers and bottom ashes from fluidized bed boilers the fraction below 0.1 mm constitutes 25% of the total at maximum, which allows for their use in the materials used in hydraulic backfill as a component comprising from 30% to 60%, respectively. Slags (10 01 01) are characterized by the lack of bonding properties, which, in case of open backfill systems that are exposed to atmospheric conditions, constitutes an advantage in comparison to bottom ashes (10 01 24), which in turn definitely exhibit bonding properties. The solution of the problem of using bottom ashes is their supply and application on a current basis.

  10. Problem of formation of nitrogen oxides during coal combustion in power plant steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Kuvaev, Yu.V.

    1992-07-01

    Analyzes a study of physical and chemical processes of nitrogen oxide formation during coal combustion conducted at Stanford University (USA). Experimental installation, pulverized coal feeding as well as measuring techniques and equipment are described. Experiments were conducted with 55 micron particles of semibituminous coal. An equation for the percentage of coal carbon converted to gaseous products is given. Active formation of NO from nitrogen content in the fuel was observed when oxygen content was under 4%. Conversion of the fuel nitrogen to NO[sub x] in the 1,350-1,850 K temperature range did not depend on gas temperature but rather on oxygen content. 2 refs.

  11. Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions

    DEFF Research Database (Denmark)

    Álvarez, L.; Yin, Chungen; Riaza, J.

    2013-01-01

    The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation....... In this work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property model, gas-phase combustion mechanism and heterogeneous char reaction model. The sub-models were...... implemented in CFD (Computational Fluid Dynamics) simulations of combustion of three coals under air-firing and various oxy-firing (21-35% vol O2 in O2/CO2 mixture) conditions in an EFR (entrained flow reactor). The predicted coal burnouts and gaseous emissions were compared against experimental results...

  12. Reduction of NOx and particulate emissions from coal-fired boilers by modification of coal nozzles and combustion tuning

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, B.; Talanker, A.; Mugenstein, A.; Shpon, G.; Vikhansky, A.; Elperin, T.; Bar-Ziv, E.; Bockelie, M.; Eddings, E.; Sarofim, A.F. [Israel Electric Corporation, Haifa (Israel). Engineering Division

    2001-07-01

    In the present paper two issues are discussed: the effect of the burner replacement on boiler performance and NOx emissions and the effect of the burner replacement on performance and efficiency of electrostatic precipitators (ESP). We also have experimented with different coal types and found the coals that together with combustion tuning met commonly accepted emission limits for NOx (less than 600 mg/dNm{sup 3}) and levels of carbon in fly ash (LOI) (approximately 5-6%) for existing boilers without low NOx burners. Our measurements were accompanied by computer simulations of the combustion of the combustion process in the boiler. Special attention was paid to detailed simulation of the flow and ignition in the near-burner zone. 7 refs., 12 figs., 5 tabs.

  13. Tracing the combustion of coal blends in a thermobalance by optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    E. Osorio; M.L.F. Ghiggi; A.C.F. Vilela; W.D. Kalkreuth; D. Alvarez; A.G. Borrego [Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil). Laboratorio de Siderurgia

    2007-07-01

    Combustion at programmed temperature in a thermobalance is a common test for the rapid assessment of coal combustibility. In this study two series of blends (low rank/medium rank coal-AB and low rank /petroleum coke-AC) with the low rank coal in three different proportions (1/4, 2/4 and 3/4) have been tested. Samples have been ground and sieved to 20-75 m prior to blend preparation. The combustion profiles indicated different behaviour for the two series of samples: the AB series showed wide curves with the presence of shoulders whereas the AC series showed two maxima corresponding to the component fuels. The comparison of the calculated and experimental curves indicated different effects of blending on the relevant temperatures and reactivity of the blends. In the AB blend both initial and peak temperatures were lower than expected and the higher the proportion of low rank coal, the larger the difference. In the AC series the burnout temperature was the parameter departing more from the expected values. In order to visualize relative combustibility of the coals the reaction was stopped at 50% conversion and the samples were examined through the microscope. The combustion of the particles followed a shrinking core pattern in which the core of the low rank particles remained isotropic whereas anisotropy development was observed in the medium rank coal. The reflectance of the coals increased with increasing the temperature at which the reaction was stopped regardless the rank of the parent coal following a linear trend. 5 refs., 5 figs., 1 tab.

  14. Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA).

    Science.gov (United States)

    Idris, Siti Shawalliah; Rahman, Norazah Abd; Ismail, Khudzir

    2012-11-01

    The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Emissions from carpet combustion in a pilot-scale rotary kiln: comparison with coal and particle-board combustion

    Energy Technology Data Exchange (ETDEWEB)

    Stephanie Lucero Konopa; James A. Mulholland; Matthew J. Realff; Paul M. Lemieux [Georgia Institute of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering

    2008-08-15

    The use of post-consumer carpet as a potential fuel substitute in cement kilns and other high-temperature processes is being considered to address the problem of huge volumes of carpet waste and the opportunity of waste-to-energy recovery. Carpet represents a high volume waste stream, provides high energy value, and contains other recoverable materials for the production of cement. This research studied the emission characteristics of burning 0.46-kg charges of chopped nylon carpet squares, pulverized coal, and particle-board pellets in a pilot-scale natural gas-fired rotary kiln. Carpet was tested with different amounts of water added. Emissions of oxygen, carbon dioxide, nitric oxide (NO), sulfur dioxide (SO{sub 2}), carbon monoxide (CO), and total hydrocarbons and temperatures were continuously monitored. It was found that carpet burned faster and more completely than coal and particle board, with a rapid volatile release that resulted in large and variable transient emission peaks. NO emissions from carpet combustion ranged from 0.06 to 0.15 g/MJ and were inversely related to CO emissions. Carpet combustion yielded higher NO emissions than coal and particleboard combustion, consistent with its higher nitrogen content. S{sub 2} emissions were highest for coal combustion, consistent with its higher sulfur content than carpet or particle board. Adding water to carpet slowed its burn time and reduced variability in the emission transients, reducing the CO peak but increasing NO emissions. Results of this study indicate that carpet waste can be used as an effective alternative fuel, with the caveats that it might be necessary to wet carpet or chop it finely to avoid excessive transient puff emissions due to its high volatility compared with other solid fuels, and that controlled mixing of combustion air might be used to control NO emissions from nylon carpet. 13 refs., 5 figs., 1 tab.

  16. Low-rank coal research

    Energy Technology Data Exchange (ETDEWEB)

    Weber, G. F.; Laudal, D. L.

    1989-01-01

    This work is a compilation of reports on ongoing research at the University of North Dakota. Topics include: Control Technology and Coal Preparation Research (SO{sub x}/NO{sub x} control, waste management), Advanced Research and Technology Development (turbine combustion phenomena, combustion inorganic transformation, coal/char reactivity, liquefaction reactivity of low-rank coals, gasification ash and slag characterization, fine particulate emissions), Combustion Research (fluidized bed combustion, beneficiation of low-rank coals, combustion characterization of low-rank coal fuels, diesel utilization of low-rank coals), Liquefaction Research (low-rank coal direct liquefaction), and Gasification Research (hydrogen production from low-rank coals, advanced wastewater treatment, mild gasification, color and residual COD removal from Synfuel wastewaters, Great Plains Gasification Plant, gasifier optimization).

  17. 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

    , 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 pulverized coal combustion in O2/CO2 and air, covering the effects of fuel, mixing conditions, temperature......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......, stoichiometry, and inlet NO level. In general, the model provides a satisfactory description of NO formation in air and oxy-fuel combustion of coal, but under some conditions, it underestimates the impact on NO of replacing N2 with CO2. According to the model, differences in the NO yield between the oxy...

  18. Simultaneous determination of devolatilization and char burnout times during fluidized bed combustion of coal

    International Nuclear Information System (INIS)

    Christofiedes, N.; Brown, R.C.

    1992-01-01

    In this paper, the authors investigate a method for simultaneous determination of devolatilization and char burnout times based on the analysis of CO 2 emissions from a fluidized bed combustor. The technique is non-intrusive and can be performed under realistic combustion conditions. The authors' method involves batching single-size coal samples in a fluidized bed combustor that is heated with propane gas or other fuel. Carbon dioxide profiles versus time for the batch tests are analyzed with a linear model to obtain characteristic time constants for coal devolatilization and char combustion which can be related to total devolatilization time and burnout time for a coal sample. The authors' approach does not require special sample preparation, can be performed in actual combustion equipment and employs standard boiler instrumentation

  19. Combustion of wet pulverized coal in reactor flow; Combustao de particulas de carvao pulverizado contendo umidade em seu interior

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Valdeci Jose [Universidade do Planalto Catarinense (UNIPLAC), Lages, SC (Brazil). Dept. de Ciencias Exatas e Tecnologicas]. E-mail: vcosta@iscc.com.br; Krioukov, Viktor [Universidade Regional do Estado do Rio Grande do Sul (UNIJUI), Ijui, RS (Brazil). Programa de Pos-Graduacao em Modelagem Matematica]. E-mail: krioukov@main.unijui.tche.br; Maliska, Clovis Raimundo [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica]. E-mail: maliska@sinmec.ufsc.br

    2000-07-01

    In this work I propose a numeric study destined to the combustion of wet pulverized coal in reacting flow. The mathematical model is composed by equations for the concentration of the substances in the reacting flow, written based in the chemical kinetics and exponential form, conservation equations and devolatilization equations, combustion of the carbon and residues. The study detects fluctuation among the temperatures of the gas and of the particles. The inclusion of the humidity as constituent part of the volatile matter doesn't affect the performance of the model, however, its presence alters the temperature profiles and the gaseous composition. With the increase of the humidity in the coal have a slight reduction in the time of combustion of the particle, what agrees with experimental data. The model foresees an increment in the difference Tp-Tg and a smaller production of CO with the increase of the wetness rate. The volatile ones, in spite of they have its fraction relatively reduced with the wetness presence they are liberated more slowly with its increment, provoking change in the position of front flame. (author)

  20. Mercury speciation and fine particle size distribution on combustion of Chinese coals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; Wang, Shuxiao; Hao, Jiming [Tsinghua Univ., Beijing (China). Dept. of Environmental Science and Engineering and State Key Joint Lab. of Environment Simulation and Pollution Control; Daukoru, Michael; Torkamani, Sarah; Biswas, Pratim [Washington Univ., St. Louis, MO (United States). Aerosol and Air Quality Research Lab.

    2013-07-01

    Coal combustion is the dominant anthropogenic mercury emission source of the world. Electrostatic precipitator (ESP) can remove almost all the particulate mercury (Hg{sub p}), and wet flue gas desulfurization (WFGD) can retain a large part of the gaseous oxidized mercury (Hg{sup 2+}). Only a small percentage of gaseous elemental mercury (Hg{sup 0}) can be abated by the air pollution control devices (APCDs). Therefore, the mercury behavior across APCDs largely depends on the mercury speciation in the flue gas exhausting from the coal combustor. To better understand the formation process of three mercury species, i.e. Hg{sup 0}, Hg{sup 2+} and Hg{sub p}, in gaseous phase and fine particles, bench-scale measurements for the flue gas exhausting from combustion of different types of coal in a drop-tube furnace set-up, were carried out. It was observed that with the limitation of reaction kinetics, higher mercury concentration in flue gas will lead to lower Hg{sup 2+} proportion. The concentration of chlorine has the opposite effect, not as significantly as that of mercury though. With the chlorine concentration increasing, the proportion of Hg{sup 2+} increases. Combusting the finer coal powder results in the formation of more Hg{sup 2+}. Mineral composition of coal and coal particle size has a great impact on fine particle formation. Al in coal is in favor of finer particle formation, while Fe in coal can benefit the formation of larger particles. The coexistence of Al and Si can strengthen the particle coagulation process. This process can also be improved by the feeding of more or finer coal powder. The oxy-coal condition can make for both the mercury oxidation process and the metal oxidation in the fine particle formation process.

  1. Thermogravimetric investigation of the co-combustion between the pyrolysis oil distillation residue and lignite.

    Science.gov (United States)

    Li, Hao; Xia, Shuqian; Ma, Peisheng

    2016-10-01

    Co-combustion of lignite with distillation residue derived from rice straw pyrolysis oil was investigated by non-isothermal thermogravimetric analysis (TGA). The addition of distillation residue improved the reactivity and combustion efficiency of lignite, such as increasing the weight loss rate at peak temperature and decreasing the burnout temperature and the total burnout. With increasing distillation residue content in the blended fuels, the synergistic interactions between distillation residue and lignite firstly increased and then decreased during co-combustion stage. Results of XRF, FTIR, (13)C NMR and SEM analysis indicated that chemical structure, mineral components and morphology of samples have great influence on the synergistic interactions. The combustion mechanisms and kinetic parameters were calculated by the Coats Redfern model, suggesting that the lowest apparent activation energy (120.19kJ/mol) for the blended fuels was obtained by blending 60wt.% distillation residue during main co-combustion stage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Coal Combustion Behavior in New Ironmaking Process of Top Gas Recycling Oxygen Blast Furnace

    Science.gov (United States)

    Zhou, Zhenfeng; Xue, Qingguo; Tang, Huiqing; Wang, Guang; Wang, Jingsong

    2017-10-01

    The top gas recycling oxygen blast furnace (TGR-OBF) is a new ironmaking process which can significantly reduce the coke ratio and emissions of carbon dioxide. To better understand the coal combustion characteristics in the TGR-OBF, a three dimensional model was developed to simulate the lance-blowpipe-tuyere-raceway of a TGR-OBF. The combustion characteristics of pulverized coal in TGR-OBF were investigated. Furthermore, the effects of oxygen concentration and temperature were also analyzed. The simulation results show that the coal burnout increased by 16.23% compared to that of the TBF. The oxygen content has an obvious effect on the burnout. At 70% oxygen content, the coal burnout is only 21.64%, with a decrease of 50.14% compared to that of TBF. Moreover, the effect of oxygen temperature is also very obvious.

  3. [Inventories of atmospheric arsenic emissions from coal combustion in China, 2005].

    Science.gov (United States)

    Tian, He-Zhong; Qu, Yi-Ping

    2009-04-15

    Anthropogenic arsenic (As) emitted from coal combustion is one of key trace elements leading to negative air pollution and national economy loss. It is of great significance to estimate the atmospheric arsenic emission for proposing relevant laws or regulations and selecting proper pollution control technologies. The inventories of atmospheric arsenic emissions from coal combustion in China were evaluated by adopting the emission factor method based on fuel consumption. Arsenic emission sources were firstly classified into several categories by economic sectors, combustion types and pollution control technologies. Then, according to provincial coal consumption and averaged arsenic concentration in the feed fuel, the inventories of atmospheric arsenic emission from coal combustion in China in 2005 were established. Coal outputand consumption in China in 2005 were 2,119.8 and 2,099.8 Mt, respectively. The total emissions of arsenic released into the atmosphere in 2005 in China were estimated at about 1,564.4 t, and Shandong ranked the largest province with 144.4 t arsenic release, followed by Hunan (141.1 t), Hebei (108.5 t), Henan (77.7 t), and Jiangsu (77.0 t), which were mainly concentrated in the eastern and central provinces of China. The arsenic emissions were largely emitted by industry sector (818.8 t) and thermal power generation sector (303.4 t), contributing 52.3% and 19.4% of the totals, respectively. About 375.5 t arsenic was estimated to be released into the atmosphere in the form of gas phase in China in 2005, with a share of 24% of the totals. In general, arsenic pollution control from coal combustion should be highlighted for the power and industry sectors in the whole country. However, arsenic poisoning caused by residential coal burning should also be paid great attention in some areas such as Xinjiang, Gansu, Qinghai and Guishou.

  4. Modeling coal combustion behavior in an ironmaking blast furnace raceway: model development and applications

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, D.; Austin, P.R.; Zulli, P.; Guo B. [BlueScope Steel Research Laboratories, Port Kembla, NSW (Australia)

    2009-03-15

    A numerical model has been developed and validated for the investigation of coal combustion phenomena under blast furnace operating conditions. The model is fully three-dimensional, with a broad capacity to analyze significant operational and equipment design changes. The model was used in a number of studies, including: Effect of cooling gas type in coaxial lance arrangements. It was found that oxygen cooling improves coal burnout by 7% compared with natural gas cooling under conditions that have the same amount of oxygen enrichment in the hot blast. Effect of coal particle size distribution. It was found that during two similar periods of operation at Port Kembla's BF6, a difference in PCI capability could be attributed to the difference in coal size distribution. Effect of longer tuyeres. Longer tuyeres were installed at Port Kembla's BF5, leading to its reline scheduled for March 2009. The model predicted an increase in blast velocity at the tuyere nose due to the combustion of volatiles within the tuyere, with implications for tuyere pressure drop and PCI capability. Effect of lance tip geometry. A number of alternate designs were studied, with the best-performing designs promoting the dispersion of the coal particles. It was also found that the base case design promoted size segregation of the coal particles, forcing smaller coal particles to one side of the plume, leaving larger coal particles on the other side. 11 refs., 15 figs., 4 tabs.

  5. Preparation and evaluation of coal-derived activated carbons for removal of mercury vapor from simulated coal combustion flue fases

    Science.gov (United States)

    Hsi, H.-C.; Chen, S.; Rostam-Abadi, M.; Rood, M.J.; Richardson, C.F.; Carey, T.R.; Chang, R.

    1998-01-01

    Coal-derived activated carbons (CDACs) were tested for their suitability in removing trace amounts of vapor-phase mercury from simulated flue gases generated by coal combustion. CDACs were prepared in bench-scale and pilot-scale fluidized-bed reactors with a three-step process, including coal preoxidation, carbonization, and then steam activation. CDACs from high-organicsulfur Illinois coals had a greater equilibrium Hg0 adsorption capacity than activated carbons prepared from a low-organic-sulfur Illinois coal. When a low-organic-sulfur CDAC was impregnated with elemental sulfur at 600 ??C, its equilibrium Hg0 adsorption capacity was comparable to the adsorption capacity of the activated carbon prepared from the high-organicsulfur coal. X-ray diffraction and sulfur K-edge X-ray absorption near-edge structure examinations showed that the sulfur in the CDACs was mainly in organic forms. These results suggested that a portion of the inherent organic sulfur in the starting coal, which remained in the CDACs, played an important role in adsorption of Hg0. Besides organic sulfur, the BET surface area and micropore area of the CDACs also influenced Hg0 adsorption capacity. The HgCl2 adsorption capacity was not as dependent on the surface area and concentration of sulfur in the CDACs as was adsorption of Hg0. The properties and mercury adsorption capacities of the CDACs were compared with those obtained for commercial Darco FGD carbon.

  6. Experimental kinetic parameters in the thermo-fluid-dynamic modelling of coal combustion

    International Nuclear Information System (INIS)

    Migliavacca, G.; Perini, M.; Parodi, E.

    2001-01-01

    The designing and the optimisation of modern and efficient combustion systems are nowadays frequently based on calculation tools for mathematical modelling, which are able to predict the evolution of the process starting from the first principles of physics. Otherwise, in many cases, specific experimental parameters are needed to describe the specific nature of the materials considered in the calculations. It is especially true in the modelling of coal combustion, which is a complex process strongly dependent on the chemical and physical features of the fuel. This paper describes some experimental techniques used to estimate the fundamental kinetic parameters of coal combustion and shows how this data may be introduced in a model calculation to predict the pollutant emissions from a real scale combustion plant [it

  7. A Pulverized Coal-Fired Boiler Optimized for Oxyfuel Combustion Technology

    Directory of Open Access Journals (Sweden)

    Tomáš Dlouhý

    2012-01-01

    Full Text Available This paper presents the results of a study on modifying a pulverized coal-fired steam boiler in a 250 MWe power plant for oxygen combustion conditions. The entry point of the study is a boiler that was designed for standard air combustion. It has been proven that simply substituting air by oxygen as an oxidizer is not sufficient for maintaining a satisfactory operating mode, not even with flue gas recycling. Boiler design optimization aggregating modifications to the boiler’s dimensions, heating surfaces and recycled flue gas flow rate, and specification of a flue gas recycling extraction point is therefore necessary in order to achieve suitable conditions for oxygen combustion. Attention is given to reducing boiler leakage, to which external pre-combustion coal drying makes a major contribution. The optimization is carried out with regard to an overall power plant conception for which a decrease in efficiency due to CO2 separation is formulated.

  8. Geochemical database of feed coal and coal combustion products (CCPs) from five power plants in the United States

    Science.gov (United States)

    Affolter, Ronald H.; Groves, Steve; Betterton, William J.; William, Benzel; Conrad, Kelly L.; Swanson, Sharon M.; Ruppert, Leslie F.; Clough, James G.; Belkin, Harvey E.; Kolker, Allan; Hower, James C.

    2011-01-01

    The principal mission of the U.S. Geological Survey (USGS) Energy Resources Program (ERP) is to (1) understand the processes critical to the formation, accumulation, occurrence, and alteration of geologically based energy resources; (2) conduct scientifically robust assessments of those resources; and (3) study the impacts of energy resource occurrence and (or) their production and use on both the environment and human health. The ERP promotes and supports research resulting in original, geology-based, non-biased energy information products for policy and decision makers, land and resource managers, other Federal and State agencies, the domestic energy industry, foreign governments, non-governmental groups, and academia. Investigations include research on the geology of oil, gas, and coal, and the impacts associated with energy resource occurrence, production, quality, and utilization. The ERP's focus on coal is to support investigations into current issues pertaining to coal production, beneficiation and (or) conversion, and the environmental impact of the coal combustion process and coal combustion products (CCPs). To accomplish these studies, the USGS combines its activities with other organizations to address domestic and international issues that relate to the development and use of energy resources.

  9. The chemical transformation of calcium in Shenhua coal during combustion in a muffle furnace

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Sida [North China Electric Power Univ., Beijing (China). School of Energy, Power and Mechanical Engineering; Ministry of Education, Beijing (China). Key Lab. of Condition Monitoring and Control for Power Plant Equipment; Zhuo, Yuqun; Chen, Changhe [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering; Shu, Xinqian [China Univ. of Mining and Technology, Beijing (China). School of Chemical and Environmental Engineering

    2013-07-01

    The chemical reaction characteristics of calcium in three samples of Shenhua coal, i.e. raw sample, hydrochloric acid washed sample and hydrochloric acid washed light fraction, during combustion in a muffle furnace have been investigated in this paper. Ca is bound by calcite and organic matter in Shenhua coal. X ray diffraction (XRD) phase analysis has been conducted to these samples' combustion products obtained by heating at different temperatures. It has been found that the organically-bound calcium could easily react with clays and transform into gehlenite and anorthite partially if combusted under 815 C, whilst the excluded minerals promoted the conversion of gehlenite to anorthite. Calcite in Shenhua coal decomposed into calcium oxide and partially transformed into calcium sulfate under 815 C, and formed gehlenite and anorthite under 1,050 C. Calcite and other HCl-dissolved minerals in Shenhua coal were responsible mainly for the characteristic that the clay minerals in Shenhua coal hardly became mullite during combustion.

  10. Formation of the gaseous phase of impurity elements from coal combustion at a thermal power plant

    International Nuclear Information System (INIS)

    Kizil'shtein, L.Ya.; Levchenko, S.V.; Peretyakt'ko, A.G.

    1991-01-01

    Data are reported on the distribution of impurity elements in their principal carriers: organic matter, iron sulfides, and clays. Tests with high-temperature combustion of coals and argillites indicate that elements associated with clay minerals largely remain in ash and slag. They do not pass to the gas phase - a factor to be considered in assessment of environmental impact from thermal power plants and specification of toxic concentration levels of impurity elements in coal

  11. Study of flame combustion of off-design binary coal blends in steam boilers

    Science.gov (United States)

    Kapustyanskii, A. A.

    2017-07-01

    Changes in the structure of the fuel consumption by the thermal power stations of Ukraine caused by failure in supplying anthracite from the Donets Basin are analyzed and the major tasks of maintaining the functioning of the coal industry are formulated. The possibility of using, in the near future, the flame combustion of off-design solid fuels in the power boilers of the thermal power plants and combined heat and power plants is studied. The article presents results of expert tests of the TPP-210A and TP-15 boilers under flame combustion of mixtures of anthracites, lean coal, and the coal from the RSA in various combinations. When combusting, such mixtures have higher values of the combustibles yield and the ash fusibility temperature. The existence of the synergetic effect in the flame combustion of binary coal blends with different degrees of metamorphism is discussed. A number of top-priority measures have been worked out that allow for switching over the boilers designed to be fired with anthracite to using blends of coals of different ranks. Zoned thermal analysis of the TP-15 boiler furnace was performed for numerical investigation of the temperature distribution between the furnace chamber zones and exploration of the possibility of the liquid slag disposal and the temperature conditions for realization of this process. A positive result was achieved by combusting anthracite culm (AC), the coal from the RSA, and their mixtures with lean coal within the entire range of the working loads of the boilers in question. The problems of normalization of the liquid slag flow were also successfully solved without closing the slag notch. The results obtained by balance experiments suggest that the characteristics of the flame combustion of a binary blend, i.e., the temperature conditions in the furnace, the support flame values, and the degree of the fuel burnout, are similar to the characteristics of the flame of the coal with a higher reactive capacity, which

  12. Thermal analysis and kinetics of coal during oxy-fuel combustion

    Science.gov (United States)

    Kosowska-Golachowska, Monika

    2017-08-01

    The pyrolysis and oxy-fuel combustion characteristics of Polish bituminous coal were studied using non-isothermal thermogravimetric analysis. Pyrolysis tests showed that the mass loss profiles were almost similar up to 870°C in both N2 and CO2 atmospheres, while further mass loss occurred in CO2 atmosphere at higher temperatures due to char-CO2 gasification. Replacement of N2 in the combustion environment by CO2 delayed the combustion of bituminous coal. At elevated oxygen levels, TG/DTG profiles shifted through lower temperature zone, ignition and burnout temperatures decreased and mass loss rate significantly increased and complete combustion was achieved at lower temperatures and shorter times. Kinetic analysis for the tested coal was performed using Kissinger-Akahira-Sunose (KAS) method. The activation energies of bituminous coal combustion at the similar oxygen content in oxy-fuel with that of air were higher than that in air atmosphere. The results indicated that, with O2 concentration increasing, the activation energies decreased.

  13. Combustion characteristics and kinetic analysis of pulverized coal under different pressure grades

    Directory of Open Access Journals (Sweden)

    Qiwei ZUO

    2016-02-01

    Full Text Available By using thermo gravimetric balance, experimental research on combustion characteristics and dynamics parameters of the typical coal injection from some domestic steelworks are conducted with non-isothermal method. The combustion characteristic parameters of the sample pulverized coal such as ignition temperature, peak temperature at maximum weight loss rate, burnout temperature, general burn exponent(S, and maximum combustion rate are studied under pressure grades of 0.1, 1.1, 2.1, 3.1 and 4.1 MPa, the activation energy (E and pre-exponential factor in the combustion process are calculated. The results show that when the pressure increases from 0.1 to 4.1 MPa, ignition temperature decreases by 85.7 K at most, peak temperature at maximum weight loss rate decreases by 249.3 K at most, burnout temperature decreases by 375 K at most, maximum weight loss rate increases by 10 times, and S increases by 33.6 times at most. It is also shown that there exists a kinetic complementation between E and ln A from the view point of dynamics, and the critical pressure of pulverized coal reaction control requirement and combustion mode transform is 3.1 MPa for the pulverized coal.

  14. Combustion and emissions characterization of pelletized coal fuels. Technical report, December 1, 1992--February 28, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, S. [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Mechanical Engineering and Energy Processes

    1993-05-01

    The aim of this project is to demonstrate that sorbent-containing coal pellets made from low grade coal or coal wastes are viable clean burning fuels, and to compare their performance with that of standard run-of-mine coal. Fuels to be investigated are: (a) carbonated pellets containing calcium hydroxide sorbent, (b) coal fines-limestone pellets with cornstarch as binder, (c) pellets made from preparation plant recovered coal containing limestone sorbent and gasification tar as binder, and (d) a standard run-of-mine Illinois seam coal. The fuels will be tested in a laboratory scale 411 diameter circulating fluidized bed combustor. Progress this quarter has centered on the development of a hydraulic press based pellet mill capable of the high compaction pressures necessary to produce the gasification tar containing pellets outlined in (c) above. Limited quantities of the pellets have been made, and the process is being fine tuned before proceeding into the production mode. Tests show that the moisture content of the coal is an important parameter that needs to be fixed within narrow limits for a given coal and binder combination to produce acceptable pellets. Combustion tests with these pellet fuels and the standard coal are scheduled for the next quarter.

  15. Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Teats, F.G.; Swift, W.M. (Argonne National Lab., IL (United States)); Banerjee, D.D. (Illinois Clean Coal Inst., Carterville, IL (United States))

    1993-01-01

    Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950[degree]C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

  16. Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Teats, F.G.; Swift, W.M. [Argonne National Lab., IL (United States); Banerjee, D.D. [Illinois Clean Coal Inst., Carterville, IL (United States)

    1993-04-01

    Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950{degree}C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

  17. Effects of catalysts on combustion characteristics and kinetics of coal-char blends

    Science.gov (United States)

    Hu, Yingjie; Wang, Zhiqiang; Cheng, Xingxing; Liu, Ming; Ma, Chunyuan

    2018-04-01

    The effects of Fe2O3, CaO, and MnO2 on the combustion characteristics and kinetics of coal-char blends were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicated that catalysts exhibited positive effects on the combustion characteristics of coal-char blends, especially in the initial period of coal-char blends combustion. With catalysts addition (mass 1.5%), it could improves volatile matter release, and reduces ignition point, promotes char to begin burning under lower temperature. The ignition index (C) was increased, respectively, by 27% for Fe2O3, 6% for CaO, 11.3% for MnO2, and the combustion characteristic index ( S ) was increased respectively, by 29% for Fe2O3, 5% for CaO, 8.3% for MnO2. In addition, two kinetic models (R2 and F1) were adopted to calculate the kinetic parameters in different stage of combustion processes. The results showed that with Fe2O3 or CaO addition, the activation energy at second stage decreases from 86.0 KJ/mol to 76.92 KJ/mol and 75.12 KJ/mol, respectively. There are no obvious decreases at the third stage of samples combustion process.

  18. Comparative study of combustion product emissions of Pakistani coal briquettes and traditional Pakistani domestic fuels

    International Nuclear Information System (INIS)

    Wachter, E.A.; Gammage, R.B.; Haas, J.W. III; Wilson, D.L.; DePriest, J.C.; Wade, J.; Ahmad, N.; Sibtain, F.; Zahid Raza, M.

    1992-10-01

    A comparative emissions study was conducted on combustion products of various solid domestic cooking fuels; the objective was to compare relative levels of organic and inorganic toxic emissions from traditional Pakistani fuels (wood, wood charcoal, and dried animal dung) with manufactured low-rank coal briquettes (Lakhra and Sor- Range coals) under conditions simulating domestic cooking. A small combustion shed 12 m 3 internal volume, air exchange rate 14 h -1 was used to simulate south Asian cooking rooms. 200-g charges of the various fuels were ignited in an Angethi stove located inside the shed, then combusted to completion; effluents from this combustion were monitored as a function of time. Measurements were made of respirable particulates, volatile and semi-volatile organics, CO, SO 2 , and NO x . Overall it appears that emissions from coal briquettes containing combustion amendments (slaked lime, clay, and potassium nitrate oxidizer) are no greater than emissions from traditional fuels, and in some cases are significantly lower; generally, emissions are highest for all fuels in the early stages of combustion

  19. Status of Westinghouse coal-fueled combustion turbine programs

    International Nuclear Information System (INIS)

    Scalzo, A.J.; Amos, D.J.; Bannister, R.L.; Garland, R.V.

    1992-01-01

    Developing clean, efficient, cost effective coal utilization technologies for future power generation is an essential part of our National Energy Strategy. Westinghouse is actively developing power plants utilizing advanced gasification, atmospheric fluidized beds (AFB), pressurized fluidized beds (PFB), and direct firing technology through programs sponsored by the U.S. Dept. of Energy (DOE). The DOE Office of Fossil Energy is sponsoring the Direct Coal-Fired Turbine program. This paper presents the status of current and potential Westinghouse Power Generation Business Unit advanced coal-fueled power generation programs as well as commercial plans

  20. Fluidized bed combustion of refuse-derived fuel in presence of protective coal ash

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer, Eduardo [CIRCE, Universidad de Zaragoza, Maria de Luna, 3, Zaragoza (Spain); Aho, Martti [VTT Processes, P.O. Box 1603, 40101 Jyvaeskylae (Finland); Silvennoinen, Jaani; Nurminen, Riku-Ville [Kvaerner Power, P.O.Box 109, FIN-33101 Tampere (Finland)

    2005-12-15

    Combustion of refuse-derived fuel (RDF) alone or together with other biomass leads to superheater fouling and corrosion in efficient power plants (with high steam values) due to vaporization and condensation of alkali chlorides. In this study, means were found to raise the portion of RDF to 40% enb without risk to boilers. This was done by co-firing RDF with coal and optimizing coal quality. Free aluminum silicate in coal captured alkalies from vaporized alkali chlorides preventing Cl condensation to superheaters. Strong fouling and corrosion were simultaneously averted. Results from 100 kW and 4 MW CFB reactors are reported. (author)

  1. Integrated engineering and cost model for management of coal combustion byproducts

    Energy Technology Data Exchange (ETDEWEB)

    Sevim, H. [Department of Mining Engineering, Southern Illinois University at Carbondale, Carbondale, Illinois (United States); Renninger, S. [US Department of Energy, Morgantown Energy Technology Center, Morgantown, West Virginia (United States)

    1998-07-01

    An integrated engineering and cost model has been developed as a part of an overall research project for exploring the technical, environmental and economic feasibility of disposing coal combustion byproducts and flue gas desulfurisation products in underground coal mines in Illinois. The features of the model have been keyed in user-friendly software. In this paper, the purpose and the structure of the model are described. The capabilities of the software are illustrated through an example involving transportation of byproducts in containers from a power plant to a mine site, and subsequent placement of the byproducts in a abandoned underground coal mine using a hydraulic injection system. 3 refs.

  2. Strength and corrosion behavior of SiC - based ceramics in hot coal combustion environments

    Energy Technology Data Exchange (ETDEWEB)

    Breder, K.; Parten, R.J. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    As part of an effort to evaluate the use of advanced ceramics in a new generation of coal-fired power plants, four SiC-based ceramics have been exposed to corrosive coal slag in a laboratory furnace and two pilot scale combustors. Initial results indicate that the laboratory experiments are valuable additions to more expensive pilot plant experiments. The results show increased corrosive attack with increased temperature, and that only slight changes in temperature may significantly alter the degree of strength degradation due to corrosive attack. The present results are part of a larger experimental matrix evaluating the behavior of ceramics in the coal combustion environment.

  3. Thermodynamic evaluation of chemical looping combustion for combined cooling heating and power production driven by coal

    International Nuclear Information System (INIS)

    Fan, Junming; Hong, Hui; Zhu, Lin; Wang, Zefeng; Jin, Hongguang

    2017-01-01

    Highlights: • An ex-situ coal gasification chemical looping combustion integrated with CCHP process has been presented. • This novel process maintains a maximum energy efficiency of 60.34%. • The fossil energy saving ratio of this process is optimize to be 27.20%. - Abstract: This study carries out an investigation concerning on the benefits of ex-situ coal gasification chemical looping combustion integrated with combined cooling, heating and power generation (CCHP-CLC) by means of thermodynamic evaluation. The coal gasification syngas is introduced into chemical looping combustion for inherent separation of CO_2 without extra energy consumed. The combustion flue gases from both air reactor and fuel reactor are sequentially fed into gas turbines for electricity production, a heat recovery vapor generator unit for further electricity generation with driving a LiBr-H_2O absorption chiller for cooling production in summer and finally a heat exchanger for daily heat water production. A preliminary parameter analysis helps to obtain the optimum operating condition, as steam-to-coal ratio (S/C) of 0.05, oxygen-to-coal ratio (O/C) of 0.75, and operating pressure of chemical looping combustion process of 5 bar. The overall energy efficiency of the CCHP-CLC process is calculated equal to 58.20% in summer compared with that of 60.34% in winter. Importantly, by utilization of such process, the reduction potential of fossil fuel (coal) consumption has been demonstrated to be 23.36% in summer and 27.20% in winter.

  4. Process to improve combustion and coalescing characteristics of coal pellets

    Energy Technology Data Exchange (ETDEWEB)

    Ban, T.E.; Marlowe, W.H.

    1980-10-23

    Baking types of coal, which occur mainly in the Midwestern States of the USA, tend to form solid layers when heated to remove tar. In order to prevent this, it is proposed to pulverize the coal, to form small pellets and to coat these pellets. A suitable coating material mentioned here is sodium carbonate. Variants of the coating process are given. The coated pellets are heated.

  5. 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.

  6. Low NOx combustion and SCR flow field optimization in a low volatile coal fired boiler.

    Science.gov (United States)

    Liu, Xing; Tan, Houzhang; Wang, Yibin; Yang, Fuxin; Mikulčić, Hrvoje; Vujanović, Milan; Duić, Neven

    2018-08-15

    Low NO x burner redesign and deep air staging have been carried out to optimize the poor ignition and reduce the NO x emissions in a low volatile coal fired 330 MW e boiler. Residual swirling flow in the tangentially-fired furnace caused flue gas velocity deviations at furnace exit, leading to flow field unevenness in the SCR (selective catalytic reduction) system and poor denitrification efficiency. Numerical simulations on the velocity field in the SCR system were carried out to determine the optimal flow deflector arrangement to improve flow field uniformity of SCR system. Full-scale experiment was performed to investigate the effect of low NO x combustion and SCR flow field optimization. Compared with the results before the optimization, the NO x emissions at furnace exit decreased from 550 to 650 mg/Nm³ to 330-430 mg/Nm³. The sample standard deviation of the NO x emissions at the outlet section of SCR decreased from 34.8 mg/Nm³ to 7.8 mg/Nm³. The consumption of liquid ammonia reduced from 150 to 200 kg/h to 100-150 kg/h after optimization. Copyright © 2018. Published by Elsevier Ltd.

  7. Study of boron behaviour in two Spanish coal combustion power plants.

    Science.gov (United States)

    Ochoa-González, Raquel; Cuesta, Aida Fuente; Córdoba, Patricia; Díaz-Somoano, Mercedes; Font, Oriol; López-Antón, M Antonia; Querol, Xavier; Martínez-Tarazona, M Rosa; Giménez, Antonio

    2011-10-01

    A full-scale field study was carried out at two Spanish coal-fired power plants equipped with electrostatic precipitator (ESP) and wet flue gas desulfurisation (FGD) systems to investigate the distribution of boron in coals, solid by-products, wastewater streams and flue gases. The results were obtained from the simultaneous sampling of solid, liquid and gaseous streams and their subsequent analysis in two different laboratories for purposes of comparison. Although the final aim of this study was to evaluate the partitioning of boron in a (co-)combustion power plant, special attention was paid to the analytical procedure for boron determination. A sample preparation procedure was optimised for coal and combustion by-products to overcome some specific shortcomings of the currently used acid digestion methods. In addition boron mass balances and removal efficiencies in ESP and FGD devices were calculated. Mass balance closures between 83 and 149% were obtained. During coal combustion, 95% of the incoming boron was collected in the fly ashes. The use of petroleum coke as co-combustible produced a decrease in the removal efficiency of the ESP (87%). Nevertheless, more than 90% of the remaining gaseous boron was eliminated via the FGD in the wastewater discharged from the scrubber, thereby causing environmental problems. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Influence of quality coal combustion and domestic stoves outbreaks steam generators and the environmental pollution

    OpenAIRE

    Petrilean, Dan Codrut

    2008-01-01

    It was drawn balance a steam generator. We determined the pollutant emissions from coal combustion in the furnace Jiu Valley steam generator with an output of 150 MW. As an example of the steam generator was considered the type BabkoK Hitachi with turbine Turbao + Atom, in cogeneration.

  9. The critical assessment of the carbon dioxide purification technologies after Oxyfuel combustion of coals

    International Nuclear Information System (INIS)

    Iovchev, M.; Gadjanov, P.; Tzvetkov, N.

    2012-01-01

    The critical assessment of the two carbon dioxide purification technologies after Oxyfuel - combustion of coals are discussed in the report. It is noticed that these technologies proposed by 'Foster Wheeler' and 'Air Products' companies are under development now (2012) and their presence in the international market is to be expected in the next years. (authors)

  10. Presentation of the health impact evaluation study of atmospheric emissions of a major coal combustion installation

    International Nuclear Information System (INIS)

    Bonnard, R.

    2004-12-01

    In the framework of a working group on the major installations, a study has been realized on a today coal combustion installation. The direct risk by inhalation and the risks bond to indirect exposure of atmospheric releases were analyzed. The calculation method is explained and the uncertainties are discussed to present the results. (A.L.B.)

  11. Analysis of Index Gases of Coal Spontaneous Combustion Using Fourier Transform Infrared Spectrometer

    Directory of Open Access Journals (Sweden)

    Xiaojun Tang

    2014-01-01

    Full Text Available Analysis of the index gases of coal for the prevention of spontaneous combustion is of great importance for the enhancement of coal mine safety. In this work, Fourier Transform Infrared Spectrometer (FTIRS is presented to be used to analyze the index gases of coal in real time to monitor spontaneous combustion conditions. Both the instrument parameters and the analysis method are introduced at first by combining characteristics of the absorption spectra of the target analyte with the analysis requirements. Next, more than ten sets of the gas mixture containing ten components (CH4, C2H6, C3H8, iso-C4H10, n-C4H10, C2H4, C3H6, C2H2, CO, and CO2 are included and analyzed with a Spectrum Two FTIRS made by Perkin Elmer. The testing results show that the detection limit of most analytes is less than 2×10-6. All the detection limits meet the monitoring requirements of coal spontaneous combustion in China, which means that FTIRS may be an ideal instrument and the analysis method used in this paper is sufficient for spontaneous combustion gas monitoring on-line and even in situ, since FTIRS has many advantages such as fast analysis, being maintenance-free, and good safety.

  12. Sulfur emission from Victorian brown coal under pyrolysis, oxy-fuel combustion and gasification conditions.

    Science.gov (United States)

    Chen, Luguang; Bhattacharya, Sankar

    2013-02-05

    Sulfur emission from a Victorian brown coal was quantitatively determined through controlled experiments in a continuously fed drop-tube furnace under three different atmospheres: pyrolysis, oxy-fuel combustion, and carbon dioxide gasification conditions. The species measured were H(2)S, SO(2), COS, CS(2), and more importantly SO(3). The temperature (873-1273 K) and gas environment effects on the sulfur species emission were investigated. The effect of residence time on the emission of those species was also assessed under oxy-fuel condition. The emission of the sulfur species depended on the reaction environment. H(2)S, SO(2), and CS(2) are the major species during pyrolysis, oxy-fuel, and gasification. Up to 10% of coal sulfur was found to be converted to SO(3) under oxy-fuel combustion, whereas SO(3) was undetectable during pyrolysis and gasification. The trend of the experimental results was qualitatively matched by thermodynamic predictions. The residence time had little effect on the release of those species. The release of sulfur oxides, in particular both SO(2) and SO(3), is considerably high during oxy-fuel combustion even though the sulfur content in Morwell coal is only 0.80%. Therefore, for Morwell coal utilization during oxy-fuel combustion, additional sulfur removal, or polishing systems will be required in order to avoid corrosion in the boiler and in the CO(2) separation units of the CO(2) capture systems.

  13. Characteristics of carbonized sludge for co-combustion in pulverized coal power plants.

    Science.gov (United States)

    Park, Sang-Woo; Jang, Cheol-Hyeon

    2011-03-01

    Co-combustion of sewage sludge can destabilize its combustion profile due to high volatility, which results in unstable flame. We carried out fuel reforming for sewage sludge by way of carbonization at pyrolysis temperature of 300-500°C. Fuel characteristics of carbonized sludge at each temperature were analyzed. As carbonization temperature increased, fuel ratio increased, volatile content reduced, and atomic ratio relation of H/C and O/C was similar to that of lignite. The analysis result of FT-IR showed the decrease of aliphatic C-H bond and O-C bond in carbonization. In the analysis result of TG-DTG, the thermogravimetry reduction temperature of carbonized sludge (CS400) was proven to be higher than that of dried sludge, but lower than that of sub-bituminous coal. Hardgrove grindability index increased in proportion to fuel ratio increase, where the carbonized sludge value of 43-110 was similar or higher than the coal value of 49-63. As for ash deposits, slagging and fouling index were higher than that of coal. When carbonized sludge (CS400) and coal were co-combusted in 1-10% according to calorific value, slagging tendency was low in all conditions, and fouling tendency was medium or high according to the compositions of coal. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Characteristics of carbonized sludge for co-combustion in pulverized coal power plants

    International Nuclear Information System (INIS)

    Park, Sang-Woo; Jang, Cheol-Hyeon

    2011-01-01

    Co-combustion of sewage sludge can destabilize its combustion profile due to high volatility, which results in unstable flame. We carried out fuel reforming for sewage sludge by way of carbonization at pyrolysis temperature of 300-500 deg. C. Fuel characteristics of carbonized sludge at each temperature were analyzed. As carbonization temperature increased, fuel ratio increased, volatile content reduced, and atomic ratio relation of H/C and O/C was similar to that of lignite. The analysis result of FT-IR showed the decrease of aliphatic C-H bond and O-C bond in carbonization. In the analysis result of TG-DTG, the thermogravimetry reduction temperature of carbonized sludge (CS400) was proven to be higher than that of dried sludge, but lower than that of sub-bituminous coal. Hardgrove grindability index increased in proportion to fuel ratio increase, where the carbonized sludge value of 43-110 was similar or higher than the coal value of 49-63. As for ash deposits, slagging and fouling index were higher than that of coal. When carbonized sludge (CS400) and coal were co-combusted in 1-10% according to calorific value, slagging tendency was low in all conditions, and fouling tendency was medium or high according to the compositions of coal.

  15. Some environmental aspects related to sulphur emissions during combustion of Bulgarian coals

    International Nuclear Information System (INIS)

    Vassileva, C.; Vassilev, S.

    2004-01-01

    The mechanism of S emissions and their capture during combustion of some Bulgarian coals (Maritza East, Maritza West, Sofia, Pernik, Bobov Dol, Balkan) was studied based on the phase-mineral transformations in the inorganic matter during gradual heating of these coals. It was found that: 1) the organic, elemental and sulphide S is released from coal at 200-700 0 C; 2) the volatile S is initially captured by intermediate Ca-, Mg-, K-, Na-, Fc-, and Ba-oxides (mainly from decomposed organic matter and carbonates) with formation of their sulphates at 200-1000 0 C; 3) the decomposition of original and newly-formed sulphates occurs at 800-1300 0 C and they are the major source of volatile SO 2 from stack emissions of thermoelectric power stations (TPSs). The described mechanism of S emissions and their capture indicates that the traditional pulverized combustion (1200-1600 0 C) of the high-sulphur Bulgarian coals in TPSs is inadequate from an environmental point of view and other alternatives should be applied. Some of them such as fluidized-bed combustion and selective blending of the coals are proposed

  16. A model of the enhancement of coal combustion using high intensity acoustic fields

    International Nuclear Information System (INIS)

    Yavuzkurt, S.; Ha, M.Y.; Koopmann, G.H.; Scaroni, A.

    1989-01-01

    In this paper a model for the enhancement of coal combustion in the presence of high intensity acoustics is developed. A high intensity acoustic field induces an oscillating velocity over pulverized coal particles otherwise entrained in the main gas stream, resulting in increased heat and mass transfer. The augmented heat and mass transfer coefficients, expressed as space- and time-averaged Nusselt and Sherwood numbers for the oscillating flow, were implemented in an existing computer code (PCGC-2) capable of predicting various aspects of pulverized coal combustion and gasification. Increases in the Nusselt and Sherwood numbers of about 45, 60 and 82.5% at sound pressure levels of 160, 165, and 170 dB for 100 μm coal particles were obtained due to increases in the acoustic slop velocity associated with the increased sound pressure levels. The main effect of the acoustic field was observed during the char combustion phase in a diffusionally controlled situation. A decrease in the char burnout length (time) of 15.7% at 160 dB and 30.2% at 170 dB was obtained compared to the case with no sound for the 100 μm coal particles

  17. Nitric oxide reduction in coal combustion: role of char surface complexes in heterogeneous reactions

    Energy Technology Data Exchange (ETDEWEB)

    Arenillas, A.; Rubiera, F.; Pis, J.J. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2002-12-15

    Nitrogen oxides are one of the major environmental problems arising from fossil fuel combustion. Coal char is relatively rich in nitrogen, and so this is an important source of nitrogen oxides during coal combustion. However, due to its carbonaceous nature, char can also reduce NO through heterogeneous reduction. The objectives of this work were on one hand to compare NO emissions from coal combustion in two different types of equipment and on the other hand to study the influence of char surface chemistry on NO reduction. A series of combustion tests were carried out in two different scale devices: a thermogravimetric analyzer coupled to a mass spectrometer and an FTIR (TG-MS-FTIR) and a fluidized bed reactor with on-line battery of analyzers. According to the results obtained, it can be said that the TG-MS-FTIR system provides valuable information about NO heterogeneous reduction and it can give good trends of the behaviour in other combustion equipments, i.e. fluidized bed combustors. It has been also pointed out that NO-char interaction depends to a large extent on temperature. In the low-temperature range NO heterogeneous reduction seems to be controlled by the evolution of surface complexes. In the high-temperature range a different mechanism is involved in NO heterogeneous reduction, the nature of the carbon matrix being a key factor. 27 refs., 6 figs., 1 tab.

  18. Nitric oxide reduction in coal combustion: role of char surface complexes in heterogeneous reactions.

    Science.gov (United States)

    Arenillas, Ana; Rubiera, Fernando; Pis, José J

    2002-12-15

    Nitrogen oxides are one of the major environmental problems arising from fossil fuel combustion. Coal char is relatively rich in nitrogen, and so this is an important source of nitrogen oxides during coal combustion. However, due to its carbonaceous nature, char can also reduce NO through heterogeneous reduction. The objectives of this work were on one hand to compare NO emissions from coal combustion in two different types of equipment and on the other hand to study the influence of char surface chemistry on NO reduction. A series of combustion tests were carried out in two different scale devices: a thermogravimetric analyzer coupled to a mass spectrometer and an FTIR (TG-MS-FTIR) and a fluidized bed reactor with an on line battery of analyzers. The TG-MS-FTIR system was also used to perform a specific study on NO heterogeneous reduction reactions using chars with different surface chemistry. According to the results obtained, it can be said that the TG-MS-FTIR system provides valuable information about NO heterogeneous reduction and it can give good trends of the behavior in other combustion equipments (i.e., fluidized bed combustors). It has been also pointed out that NO-char interaction depends to a large extent on temperature. In the low-temperature range (800 degrees C), a different mechanism is involved in NO heterogeneous reduction, the nature of the carbon matrix being a key factor.

  19. Computational fluid dynamics simulation for chemical looping combustion of coal in a dual circulation fluidized bed

    International Nuclear Information System (INIS)

    Su, Mingze; Zhao, Haibo; Ma, Jinchen

    2015-01-01

    Highlights: • CFD simulation of a 5 kW_t_h CLC reactor of coal was conducted. • Gas leakage, flow pattern and combustion efficiency of the reactor was analyzed. • Optimal condition was achieved based on operation characteristics understanding. - Abstract: A dual circulation fluidized bed system is widely accepted for chemical looping combustion (CLC) for enriching CO_2 from the utilization of fossil fuels. Due to the limitations of the measurement, the details of multiphase reactive flows in the interconnected fluidized bed reactors are difficult to obtain. Computational Fluid Dynamics (CFD) simulation provides a promising method to understand the hydrodynamics, chemical reaction, and heat and mass transfers in CLC reactors, which are very important for the rational design, optimal operation, and scaling-up of the CLC system. In this work, a 5 kW_t_h coal-fired CLC dual circulation fluidized bed system, which was developed by our research group, was first simulated for understanding gas leakage, flow pattern and combustion efficiency. The simulation results achieved good agreement with the experimental measurements, which validates the simulation model. Subsequently, to improve the combustion efficiency, a new operation condition was simulated by increasing the reactor temperature and decreasing the coal feeding. An improvement in the combustion efficiency was attained, and the simulation results for the new operation condition were also validated by the experimental measurements in the same CLC combustor. All of the above processes demonstrated the validity and usefulness of the simulation results to improve the CLC reactor operation.

  20. Toward an understanding of coal combustion in blast furnace tuyere injection

    Energy Technology Data Exchange (ETDEWEB)

    John G. Mathieson; John S. Truelove; Harold Rogers [BlueScope Steel Research, Port Kembla, NSW (Australia)

    2005-07-01

    The former Broken Hill Proprietary Company Limited, along with its successors BlueScope Steel and BHP Billiton, like many of their iron and steel making counterparts, has had a long history of investigating pulverised coal injection and combustion under the conditions of blast furnace tuyere injection. A succession of pilot scale hot models and combustion test rigs have been constructed and operated at the company's Newcastle Laboratories beginning with the pilot scale hot raceway model in 1981. Each successive generation of test rig has attempted to provide a closer approximation to the actual blast furnace situation with the current test rig (1998 to present) seeking to promote an 'expanding' combusting coal plume. Test rig configuration is demonstrated to have a significant effect on coal burnout at a nominal transit time of 20 ms. The development of the combustion test rigs has been supported through the co-development of a range of sampling and measuring techniques and the application of a number of numerical combustion models. This paper reviews some of the milestones along the path of these investigations, the current understandings and what the future potentially holds. It's not solved yet! 17 refs., 11 figs.

  1. Efficiency and emissions of coal combustion in two unvented cookstoves

    International Nuclear Information System (INIS)

    Kaoma, J.; Kasali, G.B.; Ellegaard, A.

    1994-01-01

    An improved chamber method was employed in the evaluation of the energy conversion and emission characteristics of coal in two unvented cookstoves known as the clay stove and the Maamba stove. Burn rate and stove efficiency were determined together with mission factors for carbon monoxide (CO), nitric oxide (NO) and respirable suspended particulates (RSP). Compared to Maamba stove, the clay stove exhibited a lower burn rate but higher efficiency. The clay stove recorded mean CO, SO 2 , NO 2 , NO and RSP emission factors of 200, 47, 10, 0.4 and 2.4 g/kg, respectively. The Maamba stove emission factors for the same pollutants were 170, 36, n.d., 1.2 and 8.0 g/kg, respectively. The emissions and concentrations of carbon monoxide were less than those previously found with charcoal use, but still exceeded air pollution guidelines by orders of magnitude. Thus the use of coal would not constitute any appreciable improvement over the present charcoal use. Sulphur dioxide emissions and concentrations are quite high, and would constitute a new pollutant in residential areas of Zambia. Particulate emissions and concentrations from coal are higher than from charcoal. In view of specific health risks associated with particulates from coal smoke the domestic use of raw coal is not recommended. 16 refs, 8 figs, 20 tabs

  2. Experimental investigations on combustion and emission behaviour during oxy-coal combustion

    OpenAIRE

    Dhungel, Bhupesh

    2010-01-01

    As the most abundant non-renewable energy source available, coal has traditionally played a major role in ensuring the security of energy, and will continue to play a key role in the world energy mix. The burning of coal has however always been a subject of environmental concern. In recent years, the emission of green house gases and global climate change has emerged as the largest environmental challenge. As coal fired power plants are categorised among the least carbon efficient energy prod...

  3. Numerical investigation of influence thermal preparation coal on nitric oxides formation in combustion process

    Energy Technology Data Exchange (ETDEWEB)

    Chernetskaya, N. [Siberian Federal Univ., Krasnoyarsk (Russian Federation); Chernetsky, M.; Dekterev, A. [Siberian Federal Univ., Krasnoyarsk (Russian Federation); Kutateladze Institute of Thermophysics, Novosibirsk (Russian Federation)

    2013-07-01

    Emissions of nitrogen oxides from coal combustion are a major environmental problem because they have been shown to contribute to the formation of acid rain and photochemical smog. Coal thermalpreparation before furnace delivery is effective method to reduce NOx emissions, shown by experiments in small-scale facilities (Babiy VI, Alaverdov PI, Influence of thermal preparation pulverized coal on nitric oxides outlet for combustion different metamorphized coal. ATI, 1983). This paper presents the mathematical model of burning thermal preparation coal. Validation of the model was carried out on laboratory-scale plant of All-Russia thermal engineering institute. Modeling of low-emissive burner with preliminary heating coal dust is made for the purpose of search of burner optimal constructions which provides low concentration of nitric oxides in the boiler. For modeling are used in-house CFD code ''{sigma}Flow'' (Dekterev AA, Gavrilov AA, Harlamov EB, Litvintcev KY, J Comput Technol 8(Part 1):250-255, 2003).

  4. Chemical-Looping Combustion and Gasification of Coals and Oxygen Carrier Development: A Brief Review

    Directory of Open Access Journals (Sweden)

    Ping Wang

    2015-09-01

    Full Text Available Chemical-looping technology is one of the promising CO2 capture technologies. It generates a CO2 enriched flue gas, which will greatly benefit CO2 capture, utilization or sequestration. Both chemical-looping combustion (CLC and chemical-looping gasification (CLG have the potential to be used to generate power, chemicals, and liquid fuels. Chemical-looping is an oxygen transporting process using oxygen carriers. Recently, attention has focused on solid fuels such as coal. Coal chemical-looping reactions are more complicated than gaseous fuels due to coal properties (like mineral matter and the complex reaction pathways involving solid fuels. The mineral matter/ash and sulfur in coal may affect the activity of oxygen carriers. Oxygen carriers are the key issue in chemical-looping processes. Thermogravimetric analysis (TGA has been widely used for the development of oxygen carriers (e.g., oxide reactivity. Two proposed processes for the CLC of solid fuels are in-situ Gasification Chemical-Looping Combustion (iG-CLC and Chemical-Looping with Oxygen Uncoupling (CLOU. The objectives of this review are to discuss various chemical-looping processes with coal, summarize TGA applications in oxygen carrier development, and outline the major challenges associated with coal chemical-looping in iG-CLC and CLOU.

  5. Combustion behaviors and kinetics of sewage sludge blended with pulverized coal: With and without catalysts.

    Science.gov (United States)

    Wang, Zhiqiang; Hong, Chen; Xing, Yi; Li, Yifei; Feng, Lihui; Jia, Mengmeng

    2018-04-01

    The combustion behaviors of sewage sludge (SS), pulverized coal (PC), and their blends were studied using a thermogravimetric analyzer. The effect of the mass ratio of SS to PC on the co-combustion characteristics was analyzed. The experiments showed that the ignition performance of the blends improved significantly as the mass percentage of SS increased, but its combustion intensity decreased. The burnout temperature (T b ) and comprehensive combustibility index (S) of the blends were almost unchanged when the mass percentage of SS was less than 10%. However, a high mass percentage of SS (>10%) resulted in a great increase in T b and a notable decrease in S. Subsequently, the effects of different catalysts (CaO, CeO 2 , MnO 2 , and Fe 2 O 3 ) on the combustion characteristics and activation energy of the SS/PC blend were investigated. The four catalysts promoted the release and combustion of volatile matters in the blended fuels and shifted their combustion profiles to a low temperature. In addition, their peak separating tendencies were obvious at 350-550 C, resulting in high peak widths. All the catalysts improved combustion activity of the blended fuel and accelerated fixed carbon combustion, which decreased the ignition temperature and burnout temperature of the fuels. CeO 2 had the best catalytic effects in terms of the comprehensive combustion performance and activation energy, followed closely by Fe 2 O 3 . However, the rare-earth compounds are expensive to be applied in the catalytic combustion process of SS/PC blend at present. Based on both catalytic effects and economy, Fe 2 O 3 was potentially an optimal option for catalytic combustion among the tested catalysts. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Qualitative analysis of coal combusted in boilers of the thermal power plants in Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Đurić Slavko N.

    2012-01-01

    Full Text Available In this paper we have looked into the qualitative analysis of coals in Bosnia and Herzegovina (B-H. The analysis includes the following characteristics: moisture (W, ash (A, combustible matter (Vg and lower heating value (Hd. From the statistic parameters we have determined: absolute range (R, arithmetic mean (X, standard deviation (S and variations coefficient (Cv. It has been shown that the coal characteristics (W, A, Vg, Hd have normal distribution. The analysis show that there are considerable deviations of ash characteristics: moisture (36.23%, ash (34.21%, combustible matter (16.15% and lower heating value (25.16% from the mean value which is shown by the variations coefficient (Cv. Large oscilations of mass portions: W, A, Vg and Hd around the mean value can adversely influence the function of a boiler plant and an electric filter plant in thermal power plants in B-H in which the mentioned types of coal burn. Large ash oscilations (34.21% around the mean value point out to the inability of application of dry procedures of desulphurisation of smoke gasses (FGD due to the additional quantity of ash. It has been shown that the characteristics of Bosnian types of coal do not deviate a lot from the characteristics of coal in the surrounding countries (coals of Serbia and Monte Negro. The results can be used in analysis of coal combustion in thermal power plants, optimisation of electrical-filtre, reduction of SO2 in smoke gas and other practical problems.

  7. Interactions of coal gangue and pine sawdust during combustion of their blends studied using differential thermogravimetric analysis.

    Science.gov (United States)

    Zhang, Yuanyuan; Zhang, Zhezi; Zhu, Mingming; Cheng, Fangqin; Zhang, Dongke

    2016-08-01

    The interactions between coal gangue and pine sawdust during the combustion process were studied using thermogravimetric analysis. The effect of the blending ratio, oxygen concentration and heating rate on the weight loss (TG) and differential thermogravimetric (TGA) profiles was examined. The TG and DTG curves of the blends were not additives of those of the individual materials, suggesting that interactions between coal gangue and pine sawdust had occurred during the combustion, especially in the temperature range of 400-600°C. Kinetic analysis confirmed that the combustion of coal gangue, pine sawdust and their blends was chemical reaction controlled. Further analysis revealed that the interactions between coal gangue and pine sawdust were primarily due to thermal effects rather than structural changes, with the thermal inertia of coal gangue dominating over the behaviour of the blends. The interactions decreased with decreasing the coal gangue ratio in the blend, oxygen concentration and heating rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Early detection of spontaneous combustion of coal in underground coal mines with development of an ethylene enriching system

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Jun; Xue, Sheng [CSIRO Earth Science and Resource Engineering, Kenmore (Australia); Cheng, Weimin; Wang, Gang [Shandong University of Science and Technology, Qingdao (China)

    2011-01-01

    Spontaneous combustion of coal (sponcom) is a major hazard in underground coal mining operations. If not detected early and managed properly, it can seriously affect mine safety and productivity. Gaseous products of sponcom, such as carbon monoxide, ethylene and hydrogen, are commonly used in coal mines as indicators to reflect the state of the sponcom. Studies have shown that ethylene starts to occur when sponcom reaches a characteristic temperature. However, due to dilution of ventilation air and detection limits of the instruments used for gas analysis at coal mines, ethylene cannot be detected until the sponcom has developed past its early stage, missing an optimum opportunity for mine operators to control the hazard. To address the issue, an ethylene-enriching system, based on its physical adsorption and desorption properties, has been developed to increase detection sensitivity of the ethylene concentration in mine air by about 10 times. This system has successfully been applied in a number of underground coal mines in China to detect sponcom at its early stage and enable mine operators to take effective control measures. This paper describes the ethylene enriching system and its application. (author)

  9. Use of artificial intelligence techniques for optimisation of co-combustion of coal with biomass

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.K.; Wilcox, S.J.; Ward, J. [University of Glamorgan, Pontypridd (United Kingdom). Division of Mechanical Engineering

    2006-03-15

    The optimisation of burner operation in conventional pulverised-coal-fired boilers for co-combustion applications represents a significant challenge This paper describes a strategic framework in which Artificial Intelligence (AI) techniques can be applied to solve such an optimisation problem. The effectiveness of the proposed system is demonstrated by a case study that simulates the co-combustion of coal with sewage sludge in a 500-kW pilot-scale combustion rig equipped with a swirl stabilised low-NOx burner. A series of Computational Fluid Dynamics (CFD) simulations were performed to generate data for different operating conditions, which were then used to train several Artificial Neural Networks (ANNs) to predict the co-combustion performance. Once trained, the ANNs were able to make estimations of unseen situations in a fraction of the time taken by the CFD simulation. Consequently, the networks were capable of representing the underlying physics of the CFD models and could be executed efficiently for a large number of iterations as required by optimisation techniques based on Evolutionary Algorithms (EAs). Four operating parameters of the burner, namely the swirl angles and flow rates of the secondary and tertiary combustion air were optimised with the objective of minimising the NOx and CO emissions as well as the unburned carbon at the furnace exit. The results suggest that ANNs combined with EAs provide a useful tool for optimising co-combustion processes.

  10. Characteristics estimation of coal liquefaction residue; Sekitan ekika zansa seijo no suisan ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Itonaga, M.; Imada, K. [Nippon Steel Corp., Tokyo (Japan); Okada, Y.; Inokuchi, K. [Mitsui SRC Development Co. Ltd., Tokyo (Japan)

    1996-10-28

    The paper studied a possibility of estimating characteristics of coal liquefaction residue from liquefaction conditions in the case of fixing coal kind in the NEDOL process coal liquefaction PSU. Wyoming coal was used for the study, and the already proposed simplified liquefaction reaction models were used. Among material balances explained by the models, those of asphaltene, preasphaltene, THF insoluble matters are concerned with residue composition. Ash content is separately calculated from ash balance. Reaction velocity constants of simplified liquefaction reaction models which influence the residue composition were obtained by the multiple regression method from experimental results in the past. The estimation expression of residue viscosity was introduced from residue ash/composition. When the residue composition is estimated by the model from liquefaction conditions, and the residue viscosity is obtained using it, the higher the liquefaction temperature is, the higher the residue viscosity is. The result obtained well agreed the measuring result. The simplified liquefaction model of a certain coal kind has been established, and characteristics of residue can be estimated even at liquefaction conditions which have never been experienced before if there is a certain amount of the accumulated data on residue composition/characteristics. 4 refs., 4 figs., 4 tabs.

  11. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2002-08-15

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO2 control, NOx control, and inorganic fine particle and toxic metal emissions will be determined. Previous research has yielded data on trace metal partitioning for MSS by itself, with natural gas assist, for coal plus MSS combustion together, and for coal alone. We have re-evaluated the inhalation health effects of ash aerosol from combustion of MSS both by itself and also together with coal. We have concluded that ash from the co-combustion of MSS and coal is very much worse from an inhalation health point of view, than ash from either MSS by itself or coal by itself. The reason is that ZnO is not the ''bad actor'' as had been suspected before, but the culprit is, rather, sulfated Zn. The MSS supplies the Zn and the coal supplies the sulfur, and so it is the combination of coal and MSS that makes that process environmentally bad. If MSS is to be burned, it should be burned without coal, in the absence of sulfur.

  12. Lab-scale investigation of Middle-Bosnia coals to achieve high-efficient and clean combustion technology

    Directory of Open Access Journals (Sweden)

    Smajevic Izet

    2014-01-01

    Full Text Available This paper describes full lab-scale investigation of Middle-Bosnia coals launched to support selection an appropriate combustion technology and to support optimization of the boiler design. Tested mix of Middle-Bosnia brown coals is projected coal for new co-generation power plant Kakanj Unit 8 (300-450 MWe, EP B&H electricity utility. The basic coal blend consisting of the coals Kakanj: Breza: Zenica at approximate mass ratio of 70:20:10 is low grade brown coal with very high percentage of ash - over 40%. Testing that coal in circulated fluidized bed combustion technique, performed at Ruhr-University Bohum and Doosan Lentjes GmbH, has shown its inconveniency for fluidized bed combustion technology, primarily due to the agglomeration problems. Tests of these coals in PFC (pulverized fuel combustion technology have been performed in referent laboratory at Faculty of Mechanical Engineering of Sarajevo University, on a lab-scale PFC furnace, to provide reliable data for further analysis. The PFC tests results are fitted well with previously obtained results of the burning similar Bosnian coal blends in the PFC dry bottom furnace technique. Combination of the coals shares, the process temperature and the air combustion distribution for the lowest NOx and SO2 emissions was found in this work, provided that combustion efficiency and CO emissions are within very strict criteria, considering specific settlement of lab-scale furnace. Sustainability assessment based on calculation economic and environmental indicators, in combination with Low Cost Planning method, is used for optimization the power plant design. The results of the full lab-scale investigation will help in selection optimal Boiler design, to achieve sustainable energy system with high-efficient and clean combustion technology applied for given coals.

  13. NO Reduction over Biomass and Coal Char during Simultaneous Combustion

    DEFF Research Database (Denmark)

    Zhao, Ke; Glarborg, Peter; Jensen, Anker Degn

    2013-01-01

    This paper reports an experimental study of NO reduction over chars of straw, bark, bituminous coal, and lignite. The experiments were performed in a fixed bed reactor in the temperature range 850–1150 °C. The chars were generated by in situ pyrolysis at the reaction temperature to minimize further...

  14. Fractionation of mercury stable isotopes during coal combustion and seawater flue gas desulfurization

    International Nuclear Information System (INIS)

    Huang, Shuyuan; Yuan, Dongxing; Lin, Haiying; Sun, Lumin; Lin, Shanshan

    2017-01-01

    In the current study, fractionation of mercury isotopes during coal combustion and seawater flue gas desulfurization (SFGD) in a coal-fired power plant using a SFGD system was investigated. Fourteen samples were collected from the power plant. The samples were pretreated with a combustion-trapping method and were analyzed with a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Compared with the raw coal, the bottom ash was enriched with lighter mercury isotopes with δ 202 Hg values ranging from −0.45 to −0.03‰. The fly ash was enriched with lighter mercury isotopes with δ 202 Hg values ranging from −1.49 to −0.73‰ for Chinese coal and from −1.47 to −0.62‰ for Indonesian coal. The δ 202 Hg of fresh seawater and desulfurized seawater was found to be −1.32 and −0.32‰ respectively. These δ 202 Hg values indicated that the desulfurized seawater was enriched with heavier mercury isotopes. Based upon the calculated results obtained from the mass balance equation, it was suggested that the stack emissions were enriched with lighter mercury isotopes. Mass independent fractionation was observed in most of the samples with a Δ 199 Hg/Δ 201 Hg ratio of approximately 0.96. The results help in improving the understanding of mercury isotope fractionation during coal combustion and SFGD, and are also useful in tracing the mercury emissions from coal fired power plants. - Highlights: • Spread of 1.5‰ was observed in δ 202 Hg values of raw coals and coal related samples. • The δ 202 Hg values were more negative in fly ash than those in the raw coal. • The flue gas had a significant Hg fractionation after desulfurization. • The stack emissions were enriched with lighter isotopes compared with the raw coal.

  15. Effect of the Reburning Zone Stoichiometry on the Nox Concentration at the Three-Stage Combustion of Pulverized Coal

    Directory of Open Access Journals (Sweden)

    Chernetskaya Nelya

    2016-01-01

    Full Text Available Numerical study of heat and mass transfer taking into account the combustion of coal particles in the furnace at the three-stage combustion of pulverized coal was performed. Analysis of the reburning zone stoichiometry on the concentration of nitrogen oxides at the furnace outlet was made. The values of excess air in the primary and reburning combustion zones, providing for the concentration of nitrogen oxides at the furnace outlet is not more than 350 mg/m3 and unburned carbon not more than 1 % when burning coal with a high content of nitrogen were established.

  16. Computational fluid dynamics (CFD) analysis of the coal combustion in a boiler of a thermal power plant using different kinds of the manufactured coals

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cristiano Vitorino da; Lazzari, Luis Carlos; Ziemniczak, Aline; Beskow, Arthur Bortolin [Universidade Regional Integrada do Alto Uruguai e das Missoes (URI), Erechim, RS (Brazil)], E-mails: cristiano@uricer.edu.br, arthur@uricer.edu.br

    2010-07-01

    The state of the art in computational fluid dynamics and the availability of commercial codes encourage numerical studies of combustion processes. In the present work the commercial software CFX Ansys Europe Ltd. has been used to study the combustion of pulverized coal into the boiler of a thermal power plant. The objective of this work is to obtain new information for process optimization. Different kinds of manufactured coals were numerically tested in a thermal power plant installed at the southeast region of Brazil. The simulations were made using the actual burning conditions of the boiler. Results include the residence time of the fuel into the combustion chamber, temperature fields, flow fluid mechanics, heat transfer and pollutant formation, as well as the CO and NOx concentrations, aiming to determinate the best conditions to burn the investigated coals. The numerical investigation of the phenomena involved on the coal combustion processes are used to complete the experimental information obtained in operational tests. Considering the characteristics of different kinds of manufactured coals used, with this study is possible to achieve the most efficient boiler operation parameters, with decreasing costs of electricity production and reduction of environmentally harmful emissions. It was verified that the different kinds of manufactured coals demand different operation conditions, and the kind of manufactured coal used on the combustion process has a significant effect on the pollutant formation, mainly in rel action with ash concentration. (author)

  17. [Quantitative spectrum analysis of characteristic gases of spontaneous combustion coal].

    Science.gov (United States)

    Liang, Yun-Tao; Tang, Xiao-Jun; Luo, Hai-Zhu; Sun, Yong

    2011-09-01

    Aimed at the characteristics of spontaneous combustion gas such as a variety of gases, lou limit of detection, and critical requirement of safety, Fourier transform infrared (FTIR) spectral analysis is presented to analyze characteristic gases of spontaneous combustion In this paper, analysis method is introduced at first by combing characteristics of absorption spectra of analyte and analysis requirement. Parameter setting method, sample preparation, feature variable abstract and analysis model building are taken into consideration. The methods of sample preparation, feature abstraction and analysis model are introduced in detail. And then, eleven kinds of gases were tested with Tensor 27 spectrometer. CH4, C2H6, C3H8, iC4H10, nC4H10, C2 H4, C3 H6, C3 H2, SF6, CO and CO2 were included. The optical path length was 10 cm while the spectra resolution was set as 1 cm(-1). The testing results show that the detection limit of all analytes is less than 2 x 10(-6). All the detection limits fit the measurement requirement of spontaneous combustion gas, which means that FTIR may be an ideal instrument and the analysis method used in this paper is competent for spontaneous combustion gas measurement on line.

  18. Properties of Direct Coal Liquefaction Residue Modified Asphalt Mixture

    Directory of Open Access Journals (Sweden)

    Jie Ji

    2017-01-01

    Full Text Available The objectives of this paper are to use Direct Coal Liquefaction Residue (DLCR to modify the asphalt binders and mixtures and to evaluate the performance of modified asphalt mixtures. The dynamic modulus and phase angle of DCLR and DCLR-composite modified asphalt mixture were analyzed, and the viscoelastic properties of these modified asphalt mixtures were compared to the base asphalt binder SK-90 and Styrene-Butadiene-Styrene (SBS modified asphalt mixtures. The master curves of the asphalt mixtures were shown, and dynamic and viscoelastic behaviors of asphalt mixtures were described using the Christensen-Anderson-Marasteanu (CAM model. The test results show that the dynamic moduli of DCLR and DCLR-composite asphalt mixtures are higher than those of the SK-90 and SBS modified asphalt mixtures. Based on the viscoelastic parameters of CAM models of the asphalt mixtures, the high- and low-temperature performance of DLCR and DCLR-composite modified asphalt mixtures are obviously better than the SK-90 and SBS modified asphalt mixtures. In addition, the DCLR and DCLR-composite modified asphalt mixtures are more insensitive to the frequency compared to SK-90 and SBS modified asphalt mixtures.

  19. Transformations of inorganic coal constituents in combustion systems. Volume 1, sections 1--5: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J. [ed.; Srinivasachar, S.; Wilemski, G.; Boni, A.A. [PSI Technology Co., Andover, MA (United States); Kang, Shin-Gyoo; Sarofim, A.F.; Graham, K.A.; Beer, J.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Peterson, T.W.; Wendt, J.O.L.; Gallagher, N.B.; Bool, L. [Arizona Univ., Tucson, AZ (United States); Huggins, F.E.; Huffman, G.P.; Shah, N.; Shah, A. [Kentucky Univ., Lexington, KY (United States)

    1992-11-01

    The inorganic constituents or ash contained in pulverized coal significantly increase the environmental and economic costs of coal utilization. For example, ash particles produced during combustion may deposit on heat transfer surfaces, decreasing heat transfer rates and increasing maintenance costs. The minimization of particulate emissions often requires the installation of cleanup devices such as electrostatic precipitators, also adding to the expense of coal utilization. Despite these costly problems, a comprehensive assessment of the ash formation and had never been attempted. At the start of this program, it was hypothesized that ash deposition and ash particle emissions both depended upon the size and chemical composition of individual ash particles. Questions such as: What determines the size of individual ash particles? What determines their composition? Whether or not particles deposit? How combustion conditions, including reactor size, affect these processes? remained to be answered. In this 6-year multidisciplinary study, these issues were addressed in detail. The ambitious overall goal was the development of a comprehensive model to predict the size and chemical composition distributions of ash produced during pulverized coal combustion. Results are described.

  20. Co-combustion of peach and apricot stone with coal in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Atimtay, Aysel T.; Kaynak, Burcak [Department of Environmental Engineering, Middle East Technical University, Ankara 06531 (Turkey)

    2008-02-15

    In this study a bubbling fluidized bed combustor (BFBC) having an inside diameter of 102 mm and a height of 900 mm was used to investigate the co-combustion characteristics of peach and apricot stones produced as a waste from the fruit juice industry with coal. A lignite coal was used for co-combustion. On-line concentrations of O{sub 2}, CO, CO{sub 2}, SO{sub 2}, NO{sub X} and total hydrocarbons (C{sub m}H{sub n}) were measured in the flue gas during combustion experiments. Variations of emissions of various pollutants were studied by changing the operating parameters (excess air ratio, fluidization velocity, and fuel feed rate). Temperature distribution along the bed was measured with thermocouples. For co-combustion of apricot and peach fruit stones with a lignite coal, various ratios of biomass to coal ranging from 0 to 100 wt.% were tested. For the peach stone co-combustion tests, efficiencies are about 98% and for the apricot stone co-combustion tests, efficiencies ranged between 94.7% and 96.9% for 25%, 50% and 75% of apricot stone in the fuel mixture. The results of this study have shown that as the biomass ratio in the fuel mixture increases, the combustion takes place at the upper regions of the main column. This causes higher temperatures in the freeboard than the bed. Also the CO and hydrocarbon (C{sub m}H{sub n}) emissions increase as the biomass percentage increases in the fuel mixture. This causes decrease in the combustion efficiency. These results suggest that peach and apricot stones are potential fuels that can be utilized for clean energy production in small-scale fruit juice industries by using BFBC. The percentage of peach stones or apricot stones in the fuel mixture is suggested to be below 50 wt.% in order to obtain the emission limits of EU. During the design of the BFBC, one has to be careful about the volatile matter (VM) content of the biomass. For the complete combustion of the VM, longer freeboard or secondary air addition should be

  1. Measurement of O2 in the Combustion Chamber of Apulverized Coal Boiler

    Directory of Open Access Journals (Sweden)

    Břetislav Janeba

    2012-01-01

    Full Text Available Operational measurements of the O2 concentration in the combustion chamber of a pulverized coal boiler are not yet common practice. Operators are generally satisfied with measuring the O2 concentration in the second pass of the boiler, usually behind the economizer, where a flue gas sample is extracted for analysis in a classical analyzer. A disadvantage of this approach is that there is a very weak relation between the measured value and the condition in specific locations in the fireplace, e.g. the function of the individual burners and the combustion process as a whole. A new extractionline was developed for measuring the O2 concentration in the combustion chamber. A planar lambda probe is used in this approach. The extraction line is designed to get outputs that can be used directly for diagnosis or management of the combustion in the boiler.

  2. Combustion of pulverized coal in counter-current flow

    Energy Technology Data Exchange (ETDEWEB)

    Timnat, Y M; Goldman, Y [Technion-Israel Inst. of Tech., Haifa (Israel). Faculty of Aerospace Engineering

    1991-01-01

    In this report we describe the results obtained with two prototypes of pulverized coal combustors operating in counter-current flow, one at atmospheric pressure, the other at higher pressure and compare them to the predictions of a theoretical-numerical model, we have developed. The first prototype treats a vertical configuration, eight times larger than the one treated before (Hazanov et al. 1985), while in the second a horizontal arrangement with a smaller volume is studied. Attention was focused on particle trajectories, burnout, angle of injection, ash separation by rotational motion, effects of initial particle size and temperature, impingement velocity and the effect of gravity. Main development activity was directed to achieving stable and reliable coal burning in the combustors.

  3. Considerations on valorization of biomass origin materials in co-combustion with coal in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    I. Gulyurtlu; P. Abelha; H. Lopes; A. Crujeira; I. Cabrita [DEECA-INETI, Lisbon (Portugal)

    2007-07-01

    Co-combustion of biomass materials with coal is currently gaining increasing importance, in order to meet the targets on greenhouse gas emissions, defined in the Kyoto protocol. Co-firing of coal with biomass materials could be the short-term solution in reducing CO{sub 2} emissions from power stations. The work undertaken studied co-firing of meat and bone meal (MBM), olive cake and straw pellets with bituminous coals from Colombia (CC) and Poland (PC), which are commonly used in European power stations. The co-combustion studies were carried out on the pilot fluidized bed installation of INETI. Gaseous pollutants and solid concentration in flue gases and ashes from different locations were monitored. Results obtained indicate that the co-feeding of biomass materials did not present any problem and ensured stable combustion conditions and high efficiency. However, for temperatures above 800{sup o}C, bed agglomeration could be observed for all biomass species studied. Most of the combustion of biomass material, contrary to that of coal, was observed to take place in the riser where the temperature was as high as 150-250{sup o}C above that of the bed. SO{sub 2} and NOx levels were found to be lower. The emissions of dioxins could be considerable with fuels with high Cl as is the case with straw. However, mixing of fuels with high S content could lead to a strong reduction in dioxin emissions. Ashes produced from biomass combustion may be considered for further reutilization or landfilling. Other options depend on their characteristics, chemical composition and leaching behaviour. This was evaluated in this study.

  4. 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

  5. Historical releases of mercury to air, land, and water from coal combustion.

    Science.gov (United States)

    Streets, David G; Lu, Zifeng; Levin, Leonard; Ter Schure, Arnout F H; Sunderland, Elsie M

    2018-02-15

    Coal combustion is one of the largest contemporary sources of anthropogenic mercury (Hg). It releases geologically sequestered Hg to the atmosphere, and fly ash can contaminate terrestrial and aquatic systems. We estimate that coal combustion has released a cumulative total of 38.0 (14.8-98.9, 80% C.I.) Gg (gigagrams, 10 9 g or thousand tonnes) of Hg to air, land, and water up to the year 2010, most of which (97%) has occurred since 1850. The rate of release has grown by two orders of magnitude from 0.01Ggyr -1 in 1850 to 1Ggyr -1 in 2010. Geographically, Asia and Europe each account for 32% of cumulative releases and an additional 18% is from North America. About 26.3 (10.2-68.3) Gg, 71% of the total, were directly emitted to the atmosphere, mostly from the industrial (45%) and power generation (36%) sectors, while the remainder was disposed of to land and water bodies. While Europe and North America were the major contributing regions until 1950, Asia has surpassed both in recent decades. By 2010, Asia was responsible for 69% of the total releases of Hg from coal combustion to the environment. Control technologies installed on major emitting sources capture mainly particulate and divalent Hg, and therefore the fraction of elemental Hg in emissions from coal combustion has increased over time from 0.46 in 1850 to 0.61 in 2010. About 11.8 (4.6-30.6) Gg of Hg, 31% of the total, have been transferred to land and water bodies through the disposal or utilization of Hg-containing combustion waste and collected fly ash/FGD waste; approximately 8.8Gg of this Hg have simply been discarded to waste piles or ash ponds or rivers. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Deposit Formation in a 150 MWe Utility PF-Boiler during Co-combustion of Coal and Straw

    DEFF Research Database (Denmark)

    Andersen, Karin Hedebo; Frandsen, Flemming; Hansen, P. F. B.

    2000-01-01

    A conventional pc-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion, and a 2 year demonstration program was initiated in January 1996, addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part of the demon......A conventional pc-fired boiler at the Danish energy company I/S Midtkraft has been converted to coal-straw co-combustion, and a 2 year demonstration program was initiated in January 1996, addressing several aspects of coal-straw co-combustion. Deposition trials were performed as part...... problematic deposits. Go-firing straw also caused a change in the structure of the upstream deposits. During coal combustion an ordered, "finger" structure of the larger particles with small particles between was observed, whereas during co-combustion a more random deposition of the larger particles among...... arise when burning other coals, particularly coals with a high S or alkali metal content or a low content of ash. The behavior of K, Ca, S, and Cl was evaluated by use of thermodynamic calculations. The thermodynamically stable species agree with the observed behavior in the experiments, i.e. formation...

  7. Assessment of mercury health risks to adults from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lipfert, F.W.; Moskowitz, P.D.; Fthenakis, V.M.; DePhillips, M.P.; Viren, J.; Saroff, L.

    1994-05-01

    The U.S. Environmental Protection Agency (EPA) is preparing, for the U.S. Congress, a report evaluating the need to regulate mercury (Hg) emissions from electric utilities. This study, to be completed in 1995, will have important health and economic implications. In support of these efforts, the U.S. Department of Energy, Office of Fossil Energy, sponsored a risk assessment project at Brookhaven National Laboratory (BNL) to evaluate methylmercury (MeHg) hazards independently. In the BNL study, health risks to adults resulting from Hg emissions from a hypothetical 1000 MW{sub e} coal-fired power plant were estimated using probabilistic risk assessment techniques. The approach draws on the extant knowledge in each of the important steps in the calculation chain from emissions to health effects. Estimated results at key points in the chain were compared with actual measurements to help validate the modeled estimates. Two cases were considered: the baseline case (no local impacts), and the impact case (maximum local power-plant impact). The BNL study showed that the effects of emissions of a single power plant may double the background exposures to MeHg resulting from consuming fish obtained from a localized area near the power plant. Many implicit and explicit sources of uncertainty exist in this analysis. Those that appear to be most in need of improvement include data on doses and responses for potentially sensitive subpopulations (e.g., fetal exposures). Rather than considering hypothetical situations, it would also be preferable to assess the risks associated with actual coal-fired power plants and the nearby sensitive water bodies and susceptible subpopulations. Finally, annual total Hg emissions from coal burning and from other anthropogenic sources are still uncertain; this makes it difficult to estimate the effects of U.S. coal burning on global Hg concentration levels, especially over the long term.

  8. PAH emissions from coal combustion and waste incineration.

    Science.gov (United States)

    Hsu, Wei Ting; Liu, Mei Chen; Hung, Pao Chen; Chang, Shu Hao; Chang, Moo Been

    2016-11-15

    The characteristics of PAHs that are emitted by a municipal waste incinerator (MWI) and coal-fired power plant are examined via intensive sampling. Results of flue gas sampling reveal the potential for PAH formation within the selective catalytic reduction (SCR) system of a coal-fired power plant. In the large-scale MWI, the removal efficiency of PAHs achieved with the pilot-scaled catalytic filter (CF) exceeds that achieved by activated carbon injection with a bag filter (ACI+BF) owing to the effective destruction of gas-phase contaminants by a catalyst. A significantly lower PAH concentration (1640ng/g) was measured in fly ash from a CF module than from an ACI+BF system (5650ng/g). Replacing the ACI+BF system with CF technology would significantly reduce the discharge factor (including emission and fly ash) of PAHs from 251.6 to 77.8mg/ton-waste. The emission factors of PAHs that are obtained using ACI+BF and the CF system in the MWI are 8.05 and 7.13mg/ton, respectively. However, the emission factor of MWI is significantly higher than that of coal-fired power plant (1.56mg/ton). From the perspective of total environmental management to reduce PAH emissions, replacing the original ACI+BF process with a CF system is expected to reduce environmental impact thereof. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Combustion of agro-waste with coal in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Atimtay, Aysel T. [Middle East Technical University, Department of Environmental Engineering, Ankara (Turkey)

    2010-02-15

    In this study, a review of the studies done on the co-combustion of some agro-waste in a bubbling fluidized bed combustor (BFBC) having an inside diameter of 102 mm and a height of 900 mm is given. The agro-waste used to investigate the co-combustion characteristics were peach and apricot stones produced as a waste from the fruit juice industry, and olive cake produced as a waste from the olive oil industry. These are typical wastes for a Mediterranean country. A lignite coal was used for co-combustion. On-line concentrations of O{sub 2}, CO, CO{sub 2}, SO{sub 2}, NO{sub x} and total hydrocarbons (C{sub m} H{sub n}) were measured in the flue gas during combustion experiments. Variations of emissions of various pollutants were studied by changing the operating parameters (excess air ratio, fluidization velocity and fuel feed rate). Temperature distribution along the bed was measured with thermocouples. Emissions were also monitored from the exhaust. Various combinations of coal and biomass mixtures were tested. During the combustion tests, it was observed that the volatile matter from the biomass quickly volatilizes and mostly burns in the freeboard. The temperature profiles along the bed and the freeboard also confirmed this phenomenon. It was found that as the volatile matter of the biomass increases, combustion takes place more in the freeboard region. Better combustion conditions occur at higher excess air ratios. The results showed that co-combustion with these three proposed biomasses lowers the SO{sub 2} and NO{sub x} emissions considerably. CO and hydrocarbon emissions are lower at the higher excess air ratios. (orig.)

  10. The effects of pf grind quality on coal burnout in a 1 MW combustion test facility

    Energy Technology Data Exchange (ETDEWEB)

    Richelieu Barranco; Michael Colechin; Michael Cloke; Will Gibb; Edward Lester [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering, Nottingham Fuel and Energy Centre

    2006-05-15

    A study was carried out to determine the effect of pf particle size distribution on coal burnout propensity in a 1 MW pulverised fuel burner. The specific aim of the work was to assess the improvement in combustion performance achievable by retrofitting commercially available high performance static or dynamic classifiers to existing plants. Two coals were used and were selected as representative of extremes in fuel characteristics experienced by coal importing utilities in Europe. Each coal was fired in the unit at a range of grind sizes to determine the overall impact of a variable performance from a mill. The levels of unburnt carbon in the resultant flyashes for the two coals showed significantly different behaviour. For the higher volatile coal, the unburnt carbon was found to be insensitive to grind quality. However, the coarser grinds of the other coal produced significantly lower unburnt carbon than expected when compared with the finest grinds. Generally the results indicate that the installation of improved classification technology, leading to a finer product, will help to lower unburnt carbon levels. Nevertheless, further work will be necessary to establish the levels of diminishing returns for grind size, burnout performance and grind costs. 21 refs., 4 figs., 4 tabs.

  11. 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...

  12. Influence of process parameters on coal combustion performance. Review, experiments and engineering modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lans, R.P. van der

    1997-04-01

    The objective of this study is to improve the understanding of nitrogen oxide formation and carbon burnout during the combustion of pulverized coal, and to contribute to addressing the potential of chemical engineering models for the prediction of furnace temperatures, NO emissions and the amount of carbon in ash. To this purpose, the effect of coal quality on NO and burnout has been investigated experimentally, a radiation heat balance has been developed based on a simple chemical engineering methodology, and a mixing study has been conducted in order to describe the near burner macro mixing in terms of a reactor configuration. The influence of coal type and process conditions on NO formation and carbon burnout has been investigated experimentally in a 400 MW{sub e} corner fired boiler with over fire air, a 350 MW{sub e} opposed fired boiler, and in a 160 kW{sub t} pilot scale test rig. Three different coals were fired in each of the furnaces as part of the activities in group 3 of the European Union JOULE 2 Extension project `Atmospheric Pressure Combustion of Pulverized Coal and Coal Based Blends for Power Generation`. On the pilot scale test both single stage and air staged tests were performed. A simple, one-dimensional combustion and radiation heat transfer model has been developed for the furnace of full scale boilers. The model has been applied to the two boilers mentioned above, and is validated against measured temperatures and carbon in ash concentrations. A mixing study has been performed in order to initiate an investigation of the potential of chemical engineering models to predict NO from pulverized fuel burners. (EG) 11 refs.

  13. Burnout behaviour of bituminous coals in air-staged combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kluger, F.; Spliethoff, H.; Hein, K.R.G. [University of Stuttgart, Stuttgart (Germany). Inst. of Process Engineering and Power Plant (IVD)

    2001-07-01

    In order to determine the influence on burnout by the combustion conditions and the coal preparation, three bituminous coals sold on the world market, from three different locations in Poland, South Africa, and Australia, were studied more closely. For this purpose, the coals were ground in two different particle size ranges, which, besides the influence of the combustion conditions, such a temperature, residence time, and stoichiometry, made it possible to also investigate the impact on burnout by the coal preparation. The experiments were carried out in an electrically heated entrained-flow reactor with a thermal input of 8.5 kW. The parameters for the experiments are wall temperature (1000-1350{degree}C), air ratio (0.6-1.15) and two particle sizes (70% {lt} 75 {mu}m, 90% {lt} 75 {mu}m). The results show that in general, for increasing temperatures, the burnout quality will improve. For the Australian Illawara coal, another outcome is increased NOx emissions. Lowering the air ratio in the reduction zone leads to less NOx emission but to increased unburnt matter in ash. For the smaller particle size fraction, the analysis of the different particle sizes shows an improvement of the burnout without a change in NOx emissions. 10 refs., 10 figs., 2 tabs.

  14. Coal combustion products in Europe valuable raw materials for the construction industry

    Energy Technology Data Exchange (ETDEWEB)

    Berg, W. vom; Feuerborn, H.J. [European Coal Combustion Products Association e.V., Essen (Germany)

    2005-07-01

    Coal combustion products (CCPs) are formed with the production of electricity in coal-fired power plants. The production of these CCPs has been increased by the years due to legal requirements for flue gas cleaning. The utilisation of CCPS is well is established in some European countries, based on long term experience and technical as well as environmental benefits. As CCPs are defined as waste materials by existing legislation the power industry has to handle the stigma put on the products and hamper the beneficial use. (orig.)

  15. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bradley [Univ. of Utah, Salt Lake City, UT (United States); Davis, Kevin [Univ. of Utah, Salt Lake City, UT (United States); Senior, Constance [Univ. of Utah, Salt Lake City, UT (United States); Shim, Hong Shim [Univ. of Utah, Salt Lake City, UT (United States); Otten, Brydger Van [Univ. of Utah, Salt Lake City, UT (United States); Fry, Andrew [Univ. of Utah, Salt Lake City, UT (United States); Wendt, Jost [Univ. of Utah, Salt Lake City, UT (United States); Eddings, Eric [Univ. of Utah, Salt Lake City, UT (United States); Paschedag, Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shaddix, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cox, William [Brigham Young Univ., Provo, UT (United States); Tree, Dale [Brigham Young Univ., Provo, UT (United States)

    2013-09-30

    Reaction Engineering International (REI) managed a team of experts from University of Utah, Siemens Energy, Praxair, Vattenfall AB, Sandia National Laboratories, Brigham Young University (BYU) and Corrosion Management Ltd. to perform multi-scale experiments, coupled with mechanism development, process modeling and CFD modeling, for both applied and fundamental investigations. The primary objective of this program was to acquire data and develop tools to characterize and predict impacts of CO{sub 2} flue gas recycle and burner feed design on flame characteristics (burnout, NO{sub x}, SO{sub x}, mercury and fine particle emissions, heat transfer) and operational concerns (fouling, slagging and corrosion) inherent in the retrofit of existing coal-fired boilers for oxy-coal combustion. Experimental work was conducted at Sandia National Laboratories’ Entrained Flow Reactor, the University of Utah Industrial Combustion Research Facility, and Brigham Young University. Process modeling and computational fluid dynamics (CFD) modeling was performed at REI. Successful completion of the project objectives resulted in the following key deliverables: 1) Multi-scale test data from 0.1 kW bench-scale, 100 kW and 200 kW laboratory-scale, and 1 MW semi-industrial scale combustors that describe differences in flame characteristics, fouling, slagging and corrosion for coal combustion under air-firing and oxygen-firing conditions, including sensitivity to oxy-burner design and flue gas recycle composition. 2) Validated mechanisms developed from test data that describe fouling, slagging, waterwall corrosion, heat transfer, char burnout and sooting under coal oxy-combustion conditions. The mechanisms were presented in a form suitable for inclusion in CFD models or process models. 3) Principles to guide design of pilot-scale and full-scale coal oxy-firing systems and flue gas recycle configurations, such that boiler operational impacts from oxy-combustion retrofits are minimized. 4

  16. Emission of pollutants from coal combustion in Republic of Macedonia

    International Nuclear Information System (INIS)

    Popovski, Kiril; Armenski, Slave; Dimitrova, Jasminka

    1997-01-01

    It is shown the energy consumption picture of the Republic of Macedonia. It is determined the ratio of different kind of primary energy in meeting the needs of the state. It is used a common method for determination of air pollution during coal incineration. The results of this investigation should be analysed additionally, to ensure receiving of relevant conclusions for further activities in the field of environmental protection. There are given suggestions and means for instant activities, without financial support Tere are not analysed means and methods for environmental protections which are connected with big financial investments. (Author)

  17. Co-combustion of coal and non-recyclable paper and plastic waste in a fluidised bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    D. Boavida; P. Abelha; I. Gulyurtlu; I. Cabrita [DEECA-INETI, Lisbon (Portugal)

    2003-10-01

    Co-combustion of waste with coal was carried out using a fluidised bed combustor with the aim of achieving a fuel mixture with little variations in its heating value and simultaneously reducing the accumulation of non-toxic waste material by upgrading them for energy purposes. Results obtained indicate that the feeding of waste materials plays an important role to achieve conditions for a stable combustion. The form in which the fuel is fed to the combustor makes a significant contribution to achieve desirable combustion performance and differences were observed in results regarding the combustion efficiency and emissions when waste was fed densified or in a fluffy state when it was burned mixed with coal. Part of the combustion of waste material, contrary to that of coal, was observed to take place in the freeboard where the temperature was as much as 150{sup o}C above that of the bed. 15 refs., 8 figs., 8 tabs.

  18. Dew point of combustion products of coal from the Berezovo deposit

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, V.A. (UralVTI (USSR))

    1990-11-01

    Evaluates properties of brown coal from the Berezovo deposit, Kansk-Achinsk basin, and properties of its combustion products. Coal properties are the following: sulfur content from 0.26 to 0.49%, ash content from 3.49 to 6.58%, moisture content from 31.6 to 36.9%, calorific value from 14,200 to 15,840 kJ/kg. Dew point of the combustion products amounts to 51 C and is equal to that of water vapor present in flue gases. Changing boiler output does not influence dew point. Increase in the excess air coefficient from 1.2 to 1.4 results in an increase in dew point by 2-3 K; further increase in air excess coefficient to 1.64 causes a decline in dew point by 3-4 K. 2 refs.

  19. Investigation of combustion of coal briquettes in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Boavida, Dulce; Abelha, Pedro; Gulyurtlu, Ibrahim; Cabrita, Isabel

    1999-07-01

    This paper discusses the results obtained from an experimental combustion work undertaken to investigate the behaviour of multicomponent briquettes, prepared by mixing two different particle sizes of coal and two different types of binder species. single briquettes were burned over a wide range of temperatures in a laboratory scale fluidised bed combustor facility. Nitrogen (NO{sub x}, and N{sub 2}O) and Sulphur (SO{sub 2}) oxides emissions resulting from the combustion of these briquettes were constantly monitored during the time of burning. The levels of O{sub 2}, CO{sub 2} and CO were also recorded during the same period. Experimental results showed that coal particle size influenced burn-out times and emissions levels of some of gaseous species. The hinder type was also found to have a major influence on the emissions of different pollutants.The temperature was observed to significantly influence the extent of the effects of the other operating parameters studied.

  20. Combustion of producer gas from gasification of south Sumatera lignite coal using CFD simulation

    Directory of Open Access Journals (Sweden)

    Vidian Fajri

    2017-01-01

    Full Text Available The production of gasses from lignite coal gasification is one of alternative fuel for the boiler or gas turbine. The prediction of temperature distribution inside the burner is important for the application and optimization of the producer gas. This research aims to provide the information about the influence of excess air on the temperature distribution and combustion product in the non-premixed burner. The process was carried out using producer gas from lignite coal gasification of BA 59 was produced by the updraft gasifier which is located on Energy Conversion Laboratory Mechanical Engineering Department Universitas Sriwijaya. The excess air used in the combustion process were respectively 10%, 30% and 50%. CFD Simulations was performed in this work using two-dimensional model of the burner. The result of the simulation showed an increase of excess air, a reduction in the gas burner temperature and the composition of gas (carbon dioxide, nitric oxide and water vapor.

  1. NO formation during oxy-fuel combustion of coal and biomass chars

    DEFF Research Database (Denmark)

    Zhao, Ke; Jensen, Anker Degn; Glarborg, Peter

    2014-01-01

    The yields of NO from combustion of bituminous coal, lignite, and biomass chars were investigated in O2/N2 and O2/CO 2 atmospheres. The experiments were performed in a laboratory-scale fixed-bed reactor in the temperature range of 850-1150 °C. To minimize thermal deactivation during char preparat......The yields of NO from combustion of bituminous coal, lignite, and biomass chars were investigated in O2/N2 and O2/CO 2 atmospheres. The experiments were performed in a laboratory-scale fixed-bed reactor in the temperature range of 850-1150 °C. To minimize thermal deactivation during char...

  2. Analytical methods relating to mineral matter in coal and ash from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Creelman, R.A. [Ultra-Systems Technology Pty. Ltd., Indooroopilly, Qld. (Australia)

    2002-07-01

    The paper begins by describing the minerals that occur in coal, as well as trace elements. The testing methods that are then described include those that are in the main the standard tools for the examination and assessment of minerals in coal and ash. The techniques discussed include optical and beam techniques, X-ray methods and a variety of other useful methods. 12 refs.

  3. 3-DIMENSIONAL SIMULATION AND FEASIBILITY STUDY OF BIOMASS/COAL CO-COMBUSTION BURNER

    Directory of Open Access Journals (Sweden)

    Nataliya DUNAYEVSKA

    2017-06-01

    Full Text Available Combustion of solid biomass mixed with coal in existing boilers not only reduces harmful emissions, but also allows diversifying the available fuel base. Such technology allows to implement the efficient use of food industry solid wastes, which otherwise would be dumped in piles, and thus produce harmful environmental impact. The geometrical models of research reactor and a burner thermal preprocessing of pulverized coal were developed and calculational meshes were generated. The geometrical model of the VGP-100Vpresents only fluid domain whereas the effect of cooled walls was substituted by the equivalent biudary conditions deruved on the basis of direct experimentation. The model of the VGP-100V allowed accounting for the specifics of radiative heat transfer by comparison of experimental thermo-couple measurements to the simulated by the model one. A model has been developed allowing the determination of actual temperatures of combustion gases flow based upon the reading of unsheathed thermo-couples by taking into account the reradiation of the thermo-couple beads to the channel walls. Based on the ANSYS 3-D process model in the burner of the Trypilska Thermal Power Plant (TPP for the combustion of low-reactive coal with the thermochemical preparation of the design of an actual burner has been developed. On the basis of the experimental studies of the actual burner and the above-mentioned CFD calculations, the burner draft of the 65 MW for TPP-210A boiler aimed at the implementation of biomass-coal co-combustion was designed.

  4. Pressurized fluidized bed combustion combined cycle power plant with coal gasification: Second generation pilot plant

    International Nuclear Information System (INIS)

    Farina, G.L.; Bressan, L.

    1991-01-01

    This paper presents the technical and economical background of a research and development program of a novel power generation scheme, which is based on coal gasification, pressurized fluid bed combustion and combined cycles. The participants in this program are: Foster Wheeler (project leader), Westinghouse, IGT and the USA Dept. of Energy. The paper describes the characteristics of the plant, the research program in course of implementation, the components of the pilot plant and the first results obtained

  5. Effect of oxy-fuel combustion with steam addition on coal ignition and burnout in an entrained flow reactor

    International Nuclear Information System (INIS)

    Riaza, J.; Alvarez, L.; Gil, M.V.; Pevida, C.; Pis, J.J.; Rubiera, F.

    2011-01-01

    The ignition temperature and burnout of a semi-anthracite and a high-volatile bituminous coal were studied under oxy-fuel combustion conditions in an entrained flow reactor (EFR). The results obtained under oxy-fuel atmospheres (21%O 2 -79%CO 2 , 30%O 2 -70% O 2 and 35%O 2 -65%CO 2 ) were compared with those attained in air. The replacement of CO 2 by 5, 10 and 20% of steam in the oxy-fuel combustion atmospheres was also evaluated in order to study the wet recirculation of flue gas. For the 21%O 2 -79%CO 2 atmosphere, the results indicated that the ignition temperature was higher and the coal burnout was lower than in air. However, when the O 2 concentration was increased to 30 and 35% in the oxy-fuel combustion atmosphere, the ignition temperature was lower and coal burnout was improved in comparison with air conditions. On the other hand, an increase in ignition temperature and a worsening of the coal burnout was observed when steam was added to the oxy-fuel combustion atmospheres though no relevant differences between the different steam concentrations were detected. -- Highlights: → The ignition temperature and the burnout of two thermal coals under oxy-fuel combustion conditions were determined. → The effect of the wet recirculation of flue gas on combustion behaviour was evaluated. → Addition of steam caused a worsening of the ignition temperature and coal burnout.

  6. Effect of reaction temperature on the PM10 features during coal combustion

    International Nuclear Information System (INIS)

    Sui, J.C.; Du, Y.G.; Liu, Q.C.

    2008-01-01

    Coal-fired power plants produce fine fly ash consisting of particulate matter (PM). Particulate matter less than 10 micrometers in aerodynamic diameter (PM 1 0) is of significant concern because of its adverse environmental and health impacts. This paper studied the effect of reaction temperature on particulate matter (PM 1 0) emission and its chemical composition. The emission characteristics and elemental partition of PM 1 0 from coal combustion were investigated in a drop tube furnace. The paper discussed the experimental apparatus and conditions as well as the coal properties and sample analysis. Liupanshui (LPS) bituminous coal from China was used for the study. The fuel composition of LPS coal and the composition of low temperature ash of Chinese LPS coal were described. The paper also presented the results of the study with reference to particle size distribution and emission characteristic of PM 1 0; elemental partition within PM 1 0; and effect of the reaction temperature on elemental partition within PM 1 0. The PM mass size distribution was found to be bimodal. 14 refs., 2 tabs., 6 figs

  7. FINE PARTICAL AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt; Wayne S. Seames; Art Fernandez

    2003-09-21

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and pulverized coal. The objective was to determine potential tradeoffs between CO{sub 2} mitigation through using a CO{sub 2} neutral fuel, such as municipal sewage sludge, and the emergence of other potential problems such as the emission of toxic fly ash particles. The work led to new insight into mechanisms governing the partitioning of major and trace metals from the combustion of sewage sludge, and mixtures of coal and sewage sludge. The research also showed that the co-combustion of coal and sewage sludge emitted fine particulate matter that might potentially cause greater lung injury than that from the combustion of either coal alone or municipal sewage sludge alone. The reason appeared to be that the toxicity measured required the presence of large amounts of both zinc and sulfur in particles that were inhaled. MSS provided the zinc while coal provided the sulfur. Additional research showed that the toxic effects could most likely be engineered out of the process, through the introduction of kaolinite sorbent downstream of the combustion zone, or removing the sulfur from the fuel. These results are consequences of applying ''Health Effects Engineering'' to this issue. Health Effects Engineering is a new discipline arising out of this work, and is derived from using a collaboration of combustion engineers and toxicologists to mitigate the potentially bad health effects from combustion of this biomass fuel.

  8. Characteristic Study of Shenmu Bituminous Coal Combustion with Online TG-MS-FTIR

    Science.gov (United States)

    Pan, Guanfu

    2018-01-01

    The combustion characteristics of Shenmu bituminous pulverized coal (SBC) were comprehensively investigated with a combined TG-MS-FTIR system by considering the effect of particle size, heating rate and total flowrate. The combustion products were accurately quantified by normalization and numerical analysis of MS results. The results indicate that the decrease of the particle size, heating rate and total flowrate result in lower ignition and burnout temperatures. The activation energy tends to be lower with smaller particle size, lower heating rate and total flowrate. The MS and FTIR results demonstrate that lower concentrations of different products, such as NO, NO2, HCN, CH4 and SO2 were produced with smaller particle size, slower heating rate and lower total flowrate. The decrease of particle size would lead to more contact area with oxygen and slower heating rate could provide more sufficient time for the diffusion. High total flowrate would reduce the oxygen adsorbability on the coal particle surface and shorten the residence time of oxygen, which makes the ignition difficult to occur. This work will guide to understand the combustion kinetics of pulverized coals and be beneficial to control the formation of pollutants.

  9. Combustion properties, water absorption and grindability of raw/torrefied biomass pellets and Silantek coal

    Science.gov (United States)

    Matali, Sharmeela; Rahman, Norazah Abdul; Idris, Siti Shawaliah; Yaacob, Nurhafizah

    2017-12-01

    Torrefaction, also known as mild pyrolysis, is proven to convert raw biomass into a value-added energy commodity particularly for application in combustion and co-firing systems with improved storage and handling properties. This paper aims to compare the characteristics of Malaysian bituminous coal i.e. Silantek coal with raw and torrefied biomass pellet originated from oil palm frond and fast growing tree species, Leucaena Leucocephala. Biomass samples were initially torrefied at 300 °C for 60 minutes. Resulting torrefied biomass pellets were analysed using a number of standard fuel characterisation analyses i.e. elemental analysis, proximate analysis and calorific content (high heating values) experiments. Investigations on combustion characteristics via dynamic thermogravimetric analysis (TGA), grindability and moisture uptake tests were also performed on the torrefied biomass pellets. Better quality bio-chars were produced as compared to its raw forms and with optimal process conditions, torrefaction may potentially produces a solid fuel with combustion reactivity and porosity equivalent to raw biomass while having compatible energy density and grindability to coal.

  10. Reducing emission of nitrogen oxides during combustion of black coal from the Kuzbass

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Lobov, G.V.; Gedike, I.A.

    1983-02-01

    Black coal from the Kuzbass used as fuel by the ZapSibTEhTs fossil-fuel power plant is rich in nitrogen: nitrogen content ranges from 2.8% to 3.5%. Under these conditions conventional methods of combustion cause air pollution exceeding permissible levels. A method for combustion of coal dust in stages has been successfully tested at the plant: some of the burners located in the top zone of the furnace (the BKZ-210-140F boiler) are used for air supply. From 16% to 18% of air supplied to the furnace is directed to the upper burners. Use of this system (called tertiary air supply as opposed to the secondary air system) reduced nitrogen oxide emission by 1.5 times (from 0.87 to 0.57 g/m/sup 3/). Position of nozzles used for tertiary air supply in relation to the burners used for supply of coal dust in the tangential shaped furnace is shown in a scheme. The optimum position of tertiary air supply system in relation to burners taking into account corrosion hazards as well as the hazards of reducing combustion efficiency is discussed. Recommendation on furnace design and burner position which prevent efficiency decrease and corrosion hazards are made.

  11. Immersion Freezing of Coal Combustion Ash Particles from the Texas Panhandle

    Science.gov (United States)

    Whiteside, C. L.; Tobo, Y.; Mulamba, O.; Brooks, S. D.; Mirrielees, J.; Hiranuma, N.

    2017-12-01

    Coal combustion aerosol particles contribute to the concentrations of ice-nucleating particles (INPs) in the atmosphere. Especially, immersion freezing can be considered as one of the most important mechanisms for INP formation in supercooled tropospheric clouds that exist at temperatures between 0°C and -38°C. The U.S. contains more than 550 operating coal-burning plants consuming 7.2 x 108 metric tons of coal (in 2016) to generate a total annual electricity of >2 billion MW-h, resulting in the emission of at least 4.9 x 105 metric tons of PM10 (particulate matter smaller than 10 µm in diameter). In Texas alone, 19 combustion plants generate 0.15 billion MW-h electricity and >2.4 x 104 metric tons of PM10. Here we present the immersion freezing behavior of combustion fly ash and bottom ash particles collected in the Texas Panhandle region. Two types of particulate samples, namely electron microscopy on both ash types will also be presented to relate the crystallographic and chemical properties to their ice nucleation abilities.

  12. Determination of combustible volatile matter in coal mine roadway dusts by backscatter of x-rays from a radioisotope source

    International Nuclear Information System (INIS)

    Ailwood, C.R.; Bunch, K.; Fookes, R.A.; Gravitis, V.L.; Watt, J.S.

    1977-01-01

    The combustible volatile matter in coal mine roadway dusts (CVM) has been determined using x-ray backscatter techniques. The correlation between x-ray and chemical techniques is reasonably good for the 92 samples from collieries on the Bulli seam, and the maximum error expected at the maximum level of 11.5 weight per cent CVM permitted in the N.S.W. Coal Mines Regulation Act, 1912, as amended, is about +- 2.5 weight per cent. This x-ray technique can be used only when the combustible volatile content of the coal matter (CVM) varies within a limited range, and a separate calibration is required for each coal seam. Portable equipment based on a radioisotope x-ray source and digital ratemeter makes possible simple and rapid analysis, and with adaptation to use in coal mines should lead to much more comprehensive testing of roadways and hence improved overall prevention of coal dust explosions. (author)

  13. Partitioning of selected trace elements in coal combustion products from two coal-burning power plants in the United States

    Science.gov (United States)

    Swanson, Sharon M.; Engle, Mark A.; Ruppert, Leslie F.; Affolter, Ronald H.; Jones, Kevin B.

    2013-01-01

    Samples of feed coal (FC), bottom ash (BA), economizer fly ash (EFA), and fly ash (FA) were collected from power plants in the Central Appalachian basin and Colorado Plateau to determine the partitioning of As, Cr, Hg, Pb, and Se in coal combustion products (CCPs). The Appalachian plant burns a high-sulfur (about 3.9 wt.%) bituminous coal from the Upper Pennsylvanian Pittsburgh coal bed and operates with electrostatic precipitators (ESPs), with flue gas temperatures of about 163 °C in the ESPs. At this plant, As, Pb, Hg, and Se have the greatest median concentrations in FA samples, compared to BA and EFA. A mass balance (not including the FGD process) suggests that the following percentages of trace elements are captured in FA: As (48%), Cr (58%), Pb (54%), Se (20%), and Hg (2%). The relatively high temperatures of the flue gas in the ESPs and low amounts of unburned C in FA (0.5% loss-on-ignition for FA) may have led to the low amount of Hg captured in FA. The Colorado Plateau plant burns a blend of three low-S (about 0.74 wt.%) bituminous coals from the Upper Cretaceous Fruitland Formation and operates with fabric filters (FFs). Flue gas temperatures in the baghouses are about 104 °C. The elements As, Cr, Pb, Hg, and Se have the greatest median concentrations in the fine-grained fly ash product (FAP) produced by cyclone separators, compared to the other CCPs at this plant. The median concentration of Hg in FA (0.0983 ppm) at the Colorado Plateau plant is significantly higher than that for the Appalachian plant (0.0315 ppm); this higher concentration is related to the efficiency of FFs in Hg capture, the relatively low temperatures of flue gas in the baghouses (particularly in downstream compartments), and the amount of unburned C in FA (0.29% loss-on-ignition for FA).

  14. 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...... coal/biomass blends in a pilot scale pf-boiler. The produced data provide information on the melting of the ash and its flow characteristics, as a function of temperature, which may be used to modify the temperature profile of the boiler in order to avoid slagging. Straw co-firing lowers the ash...... viscosity leading to higher stickiness of the ash particles. Wood co-firing has only minor effects, due to the composition of wood ash and the low percentage of wood in the coal/biomass blend....

  15. Generating a representative signal of coal moisture content to anticipate combustion control in thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Prieto-Fernandez, Ismael; Luengo-Garcia, J. Carlos; Alonso-Hidalgo, Manuela; Ponte-Gutierrez, Daniel [Area de Maquinas y Motores Termicos, Universidad de Oviedo, Campus Universitario s/n 33203, Asturias Gijon (Spain)

    2002-06-01

    This article describes the possibilities of continuously measuring coal moisture in the boiler feeding circuit of a thermal power station so that the measurement can be used as a signal for the boiler combustion control system. To do so, in the first place, the point through which coal would be fed into the boiler was chosen. After studying the different parts of the circuit, the feeder was selected. Then, an installation was designed, at semi-industrial scale, faithfully reproducing the operation of a belt conveyor. In order to measure the moisture content, a microwave system was installed, and a large number of coal samples with different ranks and grain sizes was tested showing eventually the likelihood of the objective.

  16. N2 O A greenhouse gas released from the combustion of coals in fluidized beds

    International Nuclear Information System (INIS)

    Boavida, D.; Lobo, L. S.; Gulyurtlu, I.; Cabrita, I.

    1996-01-01

    This paper discusses the results of the experimental work investigating the formation of N-2 O and NO during fluidized bed combustion of coals, and of chars and volatiles produced from the pyrolysis of these coals. Ammonia (N H 3 ) and hydrogen cyanide (HCN) are shown to play important roles as gas phase precursors of both NO and N 2 O. The conversion of fuel-N through N H 3 and HCN to N 2 O and NO was studied using a fluidized bed combustor in the temperature range between 973 K and 1273 K, for two different coals. The results suggest that the principal contribution to N 2 O emission Originated from volatile-N, however, char-N could also have an important role, depending upon the temperature. 1 fig., 8 tabs

  17. Trace elements in co-combustion of solid recovered fuel and coal

    DEFF Research Database (Denmark)

    Wu, Hao; Glarborg, Peter; Jappe Frandsen, Flemming

    2013-01-01

    Trace element partitioning in co-combustion of a bituminous coal and a solid recovered fuel (SRF) was studied in an entrained flow reactor. The experiments were carried out at conditions similar to pulverized coal combustion, with SRF shares of 7.9 wt.% (wet basis), 14.8 wt.% and 25.0 wt.......%. In addition, the effect of additives such as NaCl, PVC, ammonium sulphate, and kaolinite on trace element partitioning was investigated. The trace elements studied were As, Cd, Cr, Pb, Sb and Zn, since these elements were significantly enriched in SRF as compared to coal. During the experiments, bottom ash...... was collected in a chamber, large fly ash particles were collected by a cyclone with a cut-off diameter of ~2.5 μm, and the remaining fly ash particles were gathered in a filter. It was found that when coal was co-fired with SRF, the As, Cd, Pb, Sb and Zn content in filter ash/cyclone ash increased almost...

  18. Controlling the excess heat from oxy-combustion of coal by blending with biomass

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Turan, A.Z.; Yaman, S.; Kucukbayrak, S. [Istanbul Technical University, Chemical and Metallurgical Engineering Faculty, Chemical Engineering Department, 34469, Maslak, Istanbul (Turkey)

    2010-11-15

    Two different biomass species such as sunflower seed shell and hazelnut shell were blended with Soma-Denis lignite to determine the effects of co-combustion on the thermal reactivity and the burnout of the lignite sample. For this purpose, Thermogravimetric Analysis and Differential Scanning Calorimetry techniques were applied from ambient to 900 C with a heating rate of 40 C/min under dry air and pure oxygen conditions. It was found that the thermal reactivities of the biomass materials and the lignite are highly different from each other under each oxidizing medium. On the other hand, the presence of biomass in the burning medium led to important influences not only on the burnout levels but also on the heat flows. The heat flow from the burning of lignite increased fivefold when the oxidizing medium was altered from dry air to pure oxygen. But, in case of co-combustion under oxygen, the excess heat arising from combustion of lignite could be reduced and this may be helpful to control the temperature of the combustion chamber. Based on this, co-combustion of coal/biomass blends under oxygen may be suggested as an alternative method to the ''Carbon Dioxide Recycle Method'' encountered in the oxyfuel combustion systems. (author)

  19. Assessment of coal combustion in O{sub 2}+CO{sub 2} by equilibrium calculations

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Ligang [Natural Resources Canada, CANMET Energy Technology Centre, 1 Haanel Drive, Nepean, ON (Canada); Furimsky, Edward [IMAF Group, 184 Marlborough Avenue, Ottawa, ON (Canada)

    2003-04-15

    The facility for analysis of chemical thermodynamics (F*A*C*T) method based on the Gibbs energy minimization principle was used for the environmental assessment of coal combustion in O{sub 2}+CO{sub 2} mixture compared with that in air. For the former case, the calculations predict higher emissions of CO and lower emissions of NO{sub x}. For both combustion media, SO{sub x} emissions are governed by O{sub 2} concentration, whereas distribution of trace metals was unaffected when O{sub 2} concentration in the O{sub 2}+CO{sub 2} mixture approached that in air. The effect of O{sub 2}+CO{sub 2} mixture on the distribution of chlorine- and alkali-containing compounds in the vapor phase was minor compared with that in air. In spite of the large excess of CO{sub 2} in combustion medium, sulfation was the predominant reaction occurring in ash.

  20. Investigation on the ignition, thermal acceleration and characteristic temperatures of coal char combustion

    International Nuclear Information System (INIS)

    Zhang, Bin; Fu, Peifang; Liu, Yang; Yue, Fang; Chen, Jing; Zhou, Huaichun; Zheng, Chuguang

    2017-01-01

    Highlights: • A new thermal model and measuring method for the ignition temperature are proposed. • Ignition occurs in a region but not a point with ambient conditions changing. • Ignition region is measured from the minimum to maximum ignition temperature. • T_i_g_,_m_a_x of coal char in TG-DSC is in line with the ignition temperature of EFR. - Abstract: Through using a new thermal analysis model and a method of coal/char combustion, the minimum ignition temperature and minimum ignition heat of three different ranks of pulverized coal char were measured by simultaneous Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) experiments. The results show that the ignition of coal char occurs in the range between the minimum ignition temperature and the inflection-point temperature. The thermal acceleration and its gradient G_T increase with increasing heating rate and decrease with increasing coal char rank. The higher the G_T of the coal char, the more easily the ignition occurs and more rapidly the burning and burnout occur. The data show that the G_T of coal char of SLH lignite is 1.6 times more than that of coal char of ZCY bituminous and JWY anthracite in ignition zone, and 3.4 times in burning zone. The characteristic temperatures increase with increasing temperature of prepared char, heating rate and char rank. Moreover, the T_i_g_,_m_a_x calculated in DSC experiment is approximately in line with the ignition temperature obtained in the entrained flow reactor, which demonstrates the feasibility of the proposed theory.

  1. Investigation of combustion and gasification mechanically activated coal fuel of various degrees of metamorphism on the 5-MW heat setup

    Directory of Open Access Journals (Sweden)

    Butakov Evgenii

    2017-01-01

    Full Text Available The technology of mechanochemical activation of combustion and gasification of coals is of unquestionable scientific and technical interest; an increase in chemical activity of coals at their mechanically activated grinding is associated with an increase in the rate of reaction of the coal substance. To study the combustion and gasification process, the reactor model with tangential scroll input of coal-air suspension and cylindrical reaction chamber was used at the 5-MW thermal power plant. The experiments were carried out with coals of G and SS grades of the Kuznetsk deposit. Coal, ground after the boiler’s standard mill, is fed by a feeder to the disintegrator; then, it enters the scroll inlet of the reactor burner with transport air. The suspension is ignited by a gas igniting device with the power of 50 kW. In experiments on combustion and gasification of fine coal performed at the temperature in the reaction chamber of 1000-1300°C and air excess α = 0.5-0.7, the data on concentrations of CO and H2 were obtained: for coal of grade G, concentration of H2 was 6.3% and concentration of CO was 15.3%; for coal of SS grade, concentration of H2 was 9.5% and concentration of CO was 15.6%.

  2. Numerical study of flow, combustion and emissions characteristics in a 625 MWe tangentially fired boiler with composition of coal 70% LRC and 30% MRC

    Science.gov (United States)

    Sa'adiyah, Devy; Bangga, Galih; Widodo, Wawan; Ikhwan, Nur

    2017-08-01

    Tangential fired boiler is one of the methods that can produce more complete combustion. This method applied in Suralaya Power Plant, Indonesia. However, the boiler where supposed to use low rank coal (LRC), but at a given time must be mixed with medium rank coal (MRC) from another unit because of lack of LRC coal. Accordingly to the situation, the study about choosing the right position of LRC and MRC in the burner elevation must be investigated. The composition of coal is 70%LRC / 30%MRC where MRC will be placed at the lower (A & C - Case I)) or higher (E & G - Case II) elevation as the cases in this study. The study is carried out using Computational Fluid Dynamics (CFD) method. The simulation with original case (100%LRC) has a good agreement with the measurement data. As the results, MRC is more recommended at the burner elevation A & C rather than burner elevation E & G because it has closer temperature (880 K) compared with 100%LRC and has smaller local heating area between upper side wall and front wall with the range of temperature 1900 - 2000 K. For emissions, case I has smaller NOx and higher CO2 with 104 ppm and 15,6%. Moreover, it has samller O2 residue with 5,8% due to more complete combustion.

  3. Radiation and convective heat transfer, and burnout in oxy-coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    J.P. Smart; P. O' Nions; G.S. Riley [RWE npower, Swindon (United Kingdom)

    2010-09-15

    Measurements of radiative and convective heat transfer, and carbon-in-ash have been taken on the RWEn 0.5 MWth combustion test facility (CTF) firing two different coals under oxy-fuel firing conditions. The two coals fired were a Russian Coal and a South African Coal. Recycle ratios were varied within the range of 65-75% dependent on coal. Furnace exit O{sub 2} values were maintained at 3% and 6% for the majority of tests. Air firing tests were also performed to generate baseline data. The work gives a comprehensive insight into the effect of oxy-fuel combustion on both radiative and convective heat transfer, and carbon-in-ash compared to air under dry simulated recycle conditions. Results have shown peak radiative heat flux values are inversely related to the recycle ratio for the two coals studied. Conversely, the convective heat flux values increase with increasing recycle ratio. It was also observed that the axial position of the peak in radiative heat flux moves downstream away from the burner as recycle ratio is increased. A 'working range' of recycle ratios exists where both the radiative and convective heat fluxes are comparable with air. Carbon-in-ash (CIA) was measured for selected conditions. For air firing of Russian Coal, the CIA for follows and expected trend with CIA decreasing with increasing furnace exit O{sub 2}. The CIA data for the two recycle ratios of 72% and 68% for the same coal show that the CIA values are lower than for air firing for corresponding furnace exit O{sub 2} levels and vary little with the value of furnace exit O{sub 2}. CIA measurements were taken for the South African Coal for a range of recycle ratios at 3% and 6% furnace exit O{sub 2} levels. Results indicate that the CIA values are lower for higher furnace exit O{sub 2}. 32 refs., 11 figs., 1 tab.

  4. Control of spontaneous combustion of coal in goaf at high geotemperatureby injecting liquid carbon dioxide: inertand cooling characteristics of coal

    Science.gov (United States)

    Liu, Zhenling; Wen, Hu; Yu, Zhijin; Wang, Chao; Ma, Li

    2018-02-01

    The spontaneous combustion of coal in goaf at high geo temperatures is threatening safety production in coalmine. The TG-DSC is employed to study the variation of mass and energy at 4 atmospheres (mixed gases of N2, O2 and CO2) and heating rates (10°C/min) during oxidation of coal samples. The apparent activation energy and pre-exponential factor of coal oxidation decrease rapidly with increasing theCO2 concentration. Furthermore, its reaction rate is slow, its heat released reduces. Based on the conditions of 1301 face in the Longgucoalmine, a three-dimensional geometry model is developed to simulate the distributions stream field and temperature field and the variation characteristics ofCO2 concentration field after injecting liquidCO2. The results indicate that oxygen reached to depths of˜120m in goaf, 100m in the side of inlet air, and 10m in the side of outlet air before injecting liquidCO2. After injecting liquidCO2for 28.8min, the width of oxidation and heat accumulation zone is shortened by 20m, and the distance is 80m in the side of working face and 40˜60m in goafin the direction of dip affected by temperature.

  5. 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......Fly ash from pulverized coal combustion contains residual carbon that can adsorb the air-entraining admixtures (AEAs) added to control the air entrainment in concrete. This is a problem that has increased by the implementation of low-NOx combustion technologies. In this work, pulverized fuel has...... by up to a factor of 25. This was due to a lower carbon content in the ash and a lower specific AEA adsorptivity of the carbon. The latter was suggested to be caused by changes in the adsorption properties of the unburned char and a decreased formation of soot, which was found to have a large AEA...

  6. The study of partitioning of heavy metals during fluidized bed combustion of sewage sludge and coal

    Energy Technology Data Exchange (ETDEWEB)

    Gulyurtlu, I.; Lopes, M.H.; Abelha, P.; Cabrita, I.; Oliveira, J.F.S. [INETI, Lisbon (Portugal)

    2006-06-15

    The behavior of Cd, Cr, Cu, Co, Mn, Ni, Pb, Zn, and Hg during the combustion tests of a dry granular sewage sludge on a fluidized bed combustor pilot (FBC) of about 0.3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals (HM). Heavy metals were collected and analyzed from different locations of the installation, which included the stack, the two cyclones, and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40% and 80%. It is believed that in this latter case, a slightly higher temperature could have enhanced the volatilization, especially of Cd and Pb. However these metals were then retained in fly ashes captured in the cyclones. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of Hg was retained in the cyclones and the rest was emitted either with fine ash particles or in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted, for about 50%. This appeared to have significantly decreased in the case of co-combustion, as only about 75% has been emitted, due to the retention effect of cyclone ashes.

  7. The study of partitioning of heavy metals during fluidized bed combustion of sewage sludge and coal

    Energy Technology Data Exchange (ETDEWEB)

    Gulyurtlu, Ibrahim; Lopes, M. Helena; Abelha, Pedro; Cabrita, Isabel; Oliveira, J.F. Santos

    2003-07-01

    The behaviour of Cd, Cr, Cu, Co, Mn, Pb, Zn and Hg during the combustion tests of granular dry sewage sludges on a pilot FBC of about 0,3 MW was evaluated. The emissions of these heavy metals from mono-combustion were compared with those of co-combustion of the sludge with a bituminous coal. The effect of the addition of limestone was also studied in order to retain sulphur compounds and to verify its influence on the retention of heavy metals. Heavy metals were collected and analysed from different locations of the installation, which included the stack, the two cyclones and the material removed from the bed. The results showed that the volatility of metals was rather low, resulting in emissions below the legal limits of the new directive on incineration, with the exception of Hg during the mono-combustion tests. The partitioning of metals, except for Hg, appeared to follow that of ashes, amounting to levels above 90% in the bed streams in the mono-combustion case. For co-combustion, there was a lower fixation of HM in the bed ashes, mostly originating essentially from the sewage sludge, ranging between 40 and 80%. It is believed that in this latter case, a slightly higher bed temperature could have enhanced the volatilisation, especially of Cd and Pb. However these metals were then retained in cyclone ashes. In the case of Hg, the volatilisation was complete. The bed ashes were free of Hg and part of it was retained in the cyclone and emitted as both fine ash particles and in gaseous forms. In mono-combustion the Hg emissions from the stack (particles and gas) accounted for about 50%, although there was a significant amount unaccounted for. This appeared to have significantly decreased in the case of co-combustion, as only about 15% has been emitted, due to the retention effect of cyclone ashes which presented high quantities of unburned carton and possibly condensed sulphur species.

  8. Thermal behavior and kinetics of bio-ferment residue/coal blends during co-pyrolysis

    International Nuclear Information System (INIS)

    Du, Yuying; Jiang, Xuguang; Lv, Guojun; Ma, Xiaojun; Jin, Yuqi; Wang, Fei; Chi, Yong; Yan, Jianhua

    2014-01-01

    Highlights: • The Activation energy for the blends is lower than that of BR and coal when BR < 50%. • The BR/coal blends start to decompose at approximately 45 °C releasing ammonia. • The yield of gaseous products increases with increasing BR blending ratio. • NH 3 , alkanes and CO 2 increase with increasing BR blending ratio. • Interactions most likely occur between the BR and the coal during co-pyrolysis. - Abstract: In this work, the thermal behavior and kinetics of bio-ferment residue (BR) and coal blends during co-pyrolysis were investigated using TG-FTIR and kinetic analysis. The co-pyrolysis of BR and coal occurred in three major stages. The BR/coal blends lost most of their weight during the devolatilization stage. The kinetics of the BR/coal blends in this stage implied that the activation energy was lower than that of BR and coal below a certain BR blending ratio. The BR/coal blends started to decompose at approximately 45 °C, releasing ammonia followed by alkanes, carbon dioxide, methane and carbon monoxide. The total yield of gaseous products (primarily ammonia, alkanes and carbon dioxide) increased with increasing BR blending ratio. Moreover, interactions most likely occurred between the BR and the coal during co-pyrolysis

  9. Collaborative Studies for Mercury Characterization in Coal and Coal Combustion Products, Republic of South Africa

    Science.gov (United States)

    Kolker, Allan; Senior, Constance L.; van Alphen, Chris

    2014-12-15

    Mercury (Hg) analyses were obtained for 42 samples of feed coal provided by Eskom, the national electric utility of South Africa, representing all 13 coal-fired power stations operated by Eskom in South Africa. This sampling includes results for three older power stations returned to service starting in the late 2000s. These stations were not sampled in the most recent previous study. Mercury concentrations determined in the present study are similar to or slightly lower than those previously reported, and input Hg for the three stations returned to service is comparable to that for the other 10 power stations. Determination of halogen contents of the 42 feed coals confirms that chlorine contents are generally low, and as such, the extent of Hg self-capture by particulate control devices (PCDs) is rather limited. Eight density separates of a South African Highveld (#4) coal were also provided by Eskom, and these show a strong mineralogical association of Hg (and arsenic) with pyrite. The density separates were used to predict Hg and ash contents of coal products used in South Africa or exported. A suite of 48 paired samples of pulverization-mill feed coal and fly ash collected in a previous (2010) United Nations Environment Programme-sponsored study of emissions from the Duvha and Kendal power stations was obtained for further investigation in the present study. These samples show that in each station, Hg capture varies by boiler unit and confirms that units equipped with fabric filters for air pollution control are much more effective in capturing Hg than those equipped with electrostatic precipitators. Apart from tracking the performance of PCDs individually, changes resulting in improved mercury capture of the Eskom fleet are discussed. These include Hg reduction through coal selection and washing, as well as through optimization of equipment and operational parameters. Operational changes leading to increased mercury capture include increasing mercury

  10. Coal combustion by-products: A survey of use and disposal provisions

    International Nuclear Information System (INIS)

    Jagiella, D.M.

    1993-01-01

    Over 50% of all electricity in the United States is generated by the combustion of coal. Currently, coal fired power plants produce approximately 85 million to 100 million tons of coal combustion byproducts each year. The generation of these byproducts is expected to increase to 120 million tons by the year 2000, an increase of about 72% over 1984 levels. There are four basic types of byproducts produced by coal combustion - fly as, bottom ash, boiler slag, and flue gas desulfurization sludge (FGD), and are useful as engineering materials in a variety of applications. Fly ash represents nearly 75% of all ash wastes generated in the United States. Fly ash is a powder like substance with bonding properties. The properties of fly ash depend on the type of boiler utilized. The collected fly ash can be used to partially replace cement in concrete or the clay tit bricks or as part of nine reclamation. The technology for use of fly ash in cement concrete and road bases is well developed and has been practical for many years. The United States Environmental Protection Agency (USEPA) has recognized the applications of fly ash and promulgated a federal procurement guideline for the use of fly ash in cement and concrete. Although fly ash is the second most widely used waste product, much opportunity remains to expand the use of this product, In 1984, 80% of all fly ash was not recycled but rather disposed of, Ash particles that do not escape in flue gas as fly ash become bottom ash or boiler slag. Bottom ash and boiler slag settles on the bottom of the power plant's boiler. Bottom ash is a sand like substance which has some bonding capability. Depending on the type of boiler, tile bottom ash may be open-quotes dry bottom ashclose quotes or open-quotes wet bottom ashclose quotes, Wet bottom ash falls in a molten state into water

  11. Coal flotation optimization using modified flotation parameters and combustible recovery in a Jameson cell

    International Nuclear Information System (INIS)

    Vapur, Hueseyin; Bayat, Oktay; Ucurum, Metin

    2010-01-01

    This study discusses a new coal flotation optimization approach. It is conducted using modified flotation parameters and combustible recovery. The experimental work was evaluated in two stages. In the first stage, recoveries (1, 2, 3, 5 and 8 min of flotation times) of Jameson flotation operating parameters were fitted to first-order kinetic model, R = R ∞ [1 - exp (-kt)] where R was recovery at t time, R ∞ was ultimate recovery and k was the first-order rate constant to draw the time recovery curves in the experimental study. Two parameters, the ultimate recovery (R ∞ ) and first-order rate constant (k), were then obtained from the model to fit an experimental time recovery curve. A modified flotation rate constant (K m ) defined as product of R ∞ and k, i.e., K m = R ∞ * k, and selectivity index (SI) defined as the ratio of the modified rate constant of coal to the modified rate constant of ash (SI)=K m of Coal/K m of Ash), which could be collectively called 'modified flotation parameters'. It was used to determine of the sub and upper values of operation variables. In the second one, combustible recovery (%) and ash content (%) were used to optimization of the Jameson flotation variables and it was found that d 80 = 0.250 mm particle size, 1/1 vegetable oil acids/kerosene ratio, 20% solids pulp density, 0.600 L/min wash water rate and 40 cm downcomer immersion dept could be used to separate efficiently coal from ash. Final concentrate was obtained with 94.83% combustible recovery and 17.86% ash content at optimum conditions after 8 min flotation time.

  12. Partitioning behaviour of natural radionuclides during combustion of coal in thermal power plants

    International Nuclear Information System (INIS)

    Sahu, S.K.; Tiwari, M.; Bhangare, R.C.; Ajmal, P.Y.; Pandit, G.G.

    2014-01-01

    All fossil fuels contain low levels of naturally occurring radioactive substances. The environmental impact of radionuclide-containing waste products from coal combustion is an important issue. These radionuclides vaporize in the hot portions of the coal combustor and then return to the solid phase in cooler downstream zones. Indian coal used in power plants generally has high ash yield (35-45%) and is of low quality. In the burning process of coal, minerals undergo thermal decomposition, fusion, disintegration, and agglomeration. A major portion of elements in the boiler enter into slag or bottom ash, and the rest of the inorganic materials find their way into the flue gas, in fly ash or vapor. Fly and bottom ash are significant sources of exposure to these radionuclides. In the present study, coal and ash samples collected from six thermal power stations were analyzed to determine their natural radioactivity content and the partitioning behavior of these radionuclides was carried out by tracing their activities in fly and bottom ashes. The partitioning of radionuclides is strongly dependent on the size of associated ash particle. Polonium-210 was mostly associated with the finest fraction and showed large variation with particle size whereas 232 Th showed least dependence on the particle size. The high activities of all radionuclides in fly ashes than that of bottom ashes thus may be due to strong affinity of the nuclides towards the finer particle fractions. All the radionuclide distribution favored small particle sizes

  13. Effect of biomass blending on coal ignition and burnout during oxy-fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    B. Arias; C. Pevida; F. Rubiera; J.J. Pis [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2008-09-15

    Oxy-fuel combustion is a GHG abatement technology in which coal is burned using a mixture of oxygen and recycled flue gas, to obtain a rich stream of CO{sub 2} ready for sequestration. An entrained flow reactor was used in this work to study the ignition and burnout of coals and blends with biomass under oxy-fuel conditions. Mixtures of CO{sub 2}/O{sub 2} of different concentrations were used and compared with air as reference. A worsening of the ignition temperature was detected in CO{sub 2}/O{sub 2} mixtures when the oxygen concentration was the same as that of the air. However, at an oxygen concentration of 30% or higher, an improvement in ignition was observed. The blending of biomass clearly improves the ignition properties of coal in air. The burnout of coals and blends with a mixture of 79%CO{sub 2}-21%O{sub 2} is lower than in air, but an improvement is achieved when the oxygen concentration is 30 or 35%. The results of this work indicate that coal burnout can be improved by blending biomass in CO{sub 2}/O{sub 2} mixtures. 26 refs., 7 figs., 1 tab.

  14. Co-combustion of coal and non-recyclable paper & plastic waste in a fluidised bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Boavida, D.; Abelha, P.; Gulyurtlu, I.; Cabrita, I. [DEECA-INETI, Lisbon (Portugal)

    2002-07-01

    Co-combustion of waste with coal was carried out using a fluidised bed combustor with the aim of achieving a fuel mixture with little variations in its heating value and simultaneously reducing the accumulation of non-toxic waste material by upgrading them for energy purposes. Results obtained indicate that the feeding of waste materials could present serious problems which could render conditions for a stable combustion difficult to achieve. The waste was fed mixed with coal and there was some difference observed in results regarding the combustion efficiency and emissions. Part of the combustion of waste material, contrary to that of coal, was observed to take place in the freeboard where the temperature was as much as 150{degree}C above that of the bed. 6 refs., 8 figs., 8 tabs.

  15. 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...

  16. Revised users manual, Pulverized Coal Gasification or Combustion: 2-dimensional (87-PCGC-2): Final report, Volume 2. [87-PCGC-2

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.J.; Smoot, L.D.; Brewster, B.S.

    1987-12-01

    A two-dimensional, steady-state model for describing a variety of reactive and non-reactive flows, including pulverized coal combustion and gasification, is presented. Recent code revisions and additions are described. The model, referred to as 87-PCGC-2, is applicable to cylindrical axi-symmetric systems. Turbulence is accounted for in both the fluid mechanics equations and the combustion scheme. Radiation from gases, walls, and particles is taken into account using either a flux method or discrete ordinates method. The particle phase is modeled in a Lagrangian framework, such that mean paths of particle groups are followed. Several multi-step coal devolatilization schemes are included along with a heterogeneous reaction scheme that allows for both diffusion and chemical reaction. Major gas-phase reactions are modeled assuming local instantaneous equilibrium, and thus the reaction rates are limited by the turbulent rate mixing. A NO/sub x/ finite rate chemistry submodel is included which integrates chemical kinetics and the statistics of the turbulence. The gas phase is described by elliptic partial differential equations that are solved by an iterative line-by-line technique. Under-relaxation is used to achieve numerical stability. The generalized nature of the model allows for calculation of isothermal fluid mechanicsgaseous combustion, droplet combustion, particulate combustion and various mixtures of the above, including combustion of coal-water and coal-oil slurries. Both combustion and gasification environments are permissible. User information and theory are presented, along with sample problems. 106 refs.

  17. Operational experiences of (in)direct co-combustion in coal and gas fired power plants in Europe

    International Nuclear Information System (INIS)

    Van Ree, R.; Korbee, R.; Meijer, R.; Konings, T.; Van Aart, F.

    2001-02-01

    The operational experiences of direct and indirect co-combustion of biomass/waste in European coal and natural gas fired power plants are addressed. The operational experiences of mainly Dutch direct co-combustion activities in coal fired power plants are discussed; whereas an overview of European indirect co-combustion activities is presented. The technical, environmental, and economic feasibility of different indirect co-combustion concepts (i.e. upstream gasification, pyrolysis, combustion with steam-side integration) is investigated, and the results are compared with the economic preferable concept of direct co-combustion. Main technical constraints that limit the co-combustion capacity of biomass/waste in conventional coal fired power plants are: the grindability of the biomass/coal blend, the capacity of available unit components, and the danger of severe slagging, fouling, corrosion and erosion. The main environmental constraints that have to be taken into account are the quality of produced solid waste streams (fly ash, bottom ash, gypsum) and the applicable air emission regulations. 6 refs

  18. 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

    showed an ultrafine mode centered at approximately 0.1 μm. Compared with coal combustion, co-combustion of coal and SRF increased the formation of submicron particles, especially ultrafine particles below 0.2 μm. The morphology of the particles indicated that supermicron particles were primarily formed...... by the melting of minerals. The ultrafine particles were generated through nucleation and coagulation of vaporized inorganic species, while for the particles in between supermicron and ultrafine particles, condensation of vaporized species or aggregation of nucleates on the existing spherical submicron particles...... 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...

  19. Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes.

    Science.gov (United States)

    Taggart, Ross K; Hower, James C; Dwyer, Gary S; Hsu-Kim, Heileen

    2016-06-07

    Rare earth elements (REEs) are critical and strategic materials in the defense, energy, electronics, and automotive industries. The reclamation of REEs from coal combustion fly ash has been proposed as a way to supplement REE mining. However, the typical REE contents in coal fly ash, particularly in the United States, have not been comprehensively documented or compared among the major types of coal feedstocks that determine fly ash composition. The objective of this study was to characterize a broad selection of U.S. fly ashes of varied geological origin in order to rank their potential for REE recovery. The total and nitric acid-extractable REE content for more than 100 ash samples were correlated with characteristics such as the major element content and coal basin to elucidate trends in REE enrichment. Average total REE content (defined as the sum of the lanthanides, yttrium, and scandium) for ashes derived from Appalachian sources was 591 mg kg(-1) and significantly greater than in ashes from Illinois and Powder River basin coals (403 and 337 mg kg(-1), respectively). The fraction of critical REEs (Nd, Eu, Tb, Dy, Y, and Er) in the fly ashes was 34-38% of the total and considerably higher than in conventional ores (typically less than 15%). Powder River Basin ashes had the highest extractable REE content, with 70% of the total REE recovered by heated nitric acid digestion. This is likely due to the higher calcium content of Powder River Basin ashes, which enhances their solubility in nitric acid. Sc, Nd, and Dy were the major contributors to the total REE value in fly ash, based on their contents and recent market prices. Overall, this study shows that coal fly ash production could provide a substantial domestic supply of REEs, but the feasibility of recovery depends on the development of extraction technologies that could be tailored to the major mineral content and origins of the feed coal for the ash.

  20. 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.

  1. Co-combustion performance of coal with rice husks and bamboo

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, P.C.W.; Chao, C.Y.H.; Wang, J.H.; Cheung, C.W.; Kendall, G. [Hong Kong University of Science & Technology, Kowloon (China). Dept. of Mechanical Engineering

    2007-11-15

    Biomass has been regarded as an important form of renewable energy due to the reduction of greenhouse gas emission such as carbon dioxide. An experimental study of co-combustion of coal and biomass was performed in a laboratory-scale combustion facility. Rice husks and bamboo were the selected biomass fuels in this study due to their abundance in the Asia-Pacific region. Experimental parameters including the biomass blending ratio in the fuel mixture, relative moisture content and biomass grinding size were investigated. Both energy release data and pollutant emission information were obtained. Due to the decrease in the heating value from adding biomass in the fuel mixture, the combustion temperature and energy output from the co-firing process were reduced compared with coal combustion. On the other hand, gaseous pollutant emissions including carbon monoxide (CO), carbon dioxide (CO{sub 2}), nitrogen oxides (NOx) and sulfur dioxide (SO{sub 2}) were reduced and minimum energy-based emission factors were found in the range of 10-30% biomass blending ratio. With an increase in the moisture content in the biomass, decreases in combustion temperature, SO{sub 2}, NOx and CO{sub 2} emissions were observed, while an increase in CO emissions was found. It has also been observed that chemical kinetics may play an important role compared to mass diffusion in the co-firing process and the change in biomass grinding size does not have much effect on the fuel burning rate and pollutant emissions tinder the current experimental conditions.

  2. Smog chamber study on the evolution of fume from residential coal combustion.

    Science.gov (United States)

    Geng, Chunmei; Wang, Kun; Wang, Wei; Chen, Jianhua; Liu, Xiaoyu; Liu, Hongjie

    2012-01-01

    Domestic coal stoves are widely used in countryside and greenbelt residents in China for heating and cooking, and emit considerable pollutants to the atmosphere because of no treatment of their exhaust, which can result in deteriorating local air quality. In this study, a dynamic smog chamber was used to investigate the real-time emissions of gaseous and particulate pollutants during the combustion process and a static smog chamber was used to investigate the fume evolution under simulate light irradiation. The real-time emissions revealed that the total hydrocarbon (THC) and CO increased sharply after ignition, and then quickly decreased, indicating volatilization of hydrocarbons with low molecular weight and incomplete combustion at the beginning stage of combustion made great contribution to these pollutants. There was evident shoulder peak around 10 min combustion for both THC and CO, revealing the emissions from vitrinite combustion. Additionally, another broad emission peak of CO after 30 min was also observed, which was ascribed to the incomplete combustion of the inertinite. Compared with THC and CO, there was only one emission peak for NOx, SO2 and particular matters at the beginning stage of combustion. The fume evolution with static chamber simulation indicated that evident consumption of SO2 and NOx as well as new particle formation were observed. The consumption rates for SO2 and NOx were about 3.44% hr(-1) and 3.68% hr(-1), the new particle formation of nuclei particles grew at a rate of 16.03 nm/hr during the first reaction hour, and the increase of the diameter of accumulation mode particles was evident. The addition of isoprene to the diluted mixture of the fume could promote 03 and secondary particle formation.

  3. Appendices 1-3 - the effects of combustion on ash and deposits from low rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Ledger, R.C.; Ottrey, A.L.; Mackay, G.H.

    1985-12-01

    Thermomechanical analyses (TMA) of ashes derived from combustion of fourteen coal samples from Victorian and South Australian coalfields are presented in the results volumes of this report (Volume 2-4). This appendix describes the analytical equipment used, the modifications that were incorporated and the technique developed for analysis and interpretation of the data. To aid identification, limited numbers of analyses were performed on reference materials, the results of which are presented in this appendix. Analyses were performed on a modified Stanton Redcroft 790 series thermomechanical analyser. The aim was to identify components in the ashes and to gain an understanding of the sintering and fusion behaviour of the ashes up to temperatures encountered in large scale boilers. As part of the main project, ashes were also submitted to simultaneous Differential Thermal Analysis and Thermogravimetry (DTA-TG). For each coal burnt in this investigation the Test Bank 1 and precipitator ashes produced at a flame temperature of 1200/sup o/C and 3% excess oxygen were examined by TMA, as were ashes from tests at other flame temperatures and at 3% excess oxygen for four of the coals. This was to investigate the effects of variation in combustion conditions on ash properties. The results are presented in Volume 2-4 of this report as tables, giving details of events and assignments and as a formalised TMA pattern for each ash tested.

  4. Dew point measurements of flue gases in steam generators with brown coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Schinkel, W.

    1980-01-01

    This paper examines empirical data on sulfuric acid condensation and resulting internal corrosion in brown coal fired steam generators. Due to the high sulfur content in brown coal (0.5% to 5.0%) and relative short duration of the gases in the combustion chamber the concentrations of sulfur trioxide present in the flue gases can condense at the heat exchange surfaces of the steam generators. A number of diagrams show sulfuric acid dew point temperatures depending on brown coal sulfur content, the influence of combustion air supply on the dew point, and condensing speed and the rate of corrosion in relation to different heat exchange surface temperatures. The conclusion is made that a five-fold increase in corrosion can be caused by a 10 K higher flue gas dew point, a 5 K cooling of heating surfaces can also cause heavy corrosion at a certain dew point. Maximum corrosion results at 20 to 50 K differences between flue gas dew point and heat exchange surfaces. Optimum operation of steam generators with minimal internal corrosion requires the consideration of flue gas and heating surface temperatures as well as flue gas sulfur acid dew points. (10 refs.) (In German)

  5. Effect of primary air content on formation of nitrogen oxides during combustion of Ehkibastuz coal

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Imankulov, Eh.R.

    1986-01-01

    Investigations are discussed carried out in a pilot plant at the Kaz. Power Engineering Scientific Research Institute into the effect of the amount of primary air in coal-dust flame on the final concentration of nitrogen oxides in flue gases. The tests were carried out in a 7500 mm high, 1600 mm dia vertical cylindrical combustion chamber having type P-57 burner, and air dispersed fuel plus additional air supplies located at the top. Amounts of coal dust fed by a drum feeder along the air pipe varied from 100-600 kg/h. The required air was supplied by 5000 m/sup 3//h Type TK-700/5 blowers at 0.04 MPa. Ehkibastuz coal samples contained: 1.3% moisture; 48.1% ash; 38.02% carbon; 2.56% hydrogen; 0.73% sulfur; 0.60% nitrogen; heat of combustion was 14.3 MJ/kg. Results obtained indicate that variations in the amount of primary air in swirl flow burners affect formation of fuel nitrogen; there is an optimum volume at which minimum quantities of nitrogen oxides are formed. Either an increase or decrease in the primary air results in a rise in nitrogen oxide concentration. 3 references.

  6. Utilization of coal ash/coal combustion products for mine reclamation

    International Nuclear Information System (INIS)

    Dolence, R.C.; Giovannitti, E.

    1997-01-01

    Society's demand for an inexpensive fuel, combined with ignorance of the long term impacts, has left numerous scars on the Pennsylvania landscape. There are over 250,000 acres of abandoned surface mines with dangerous highwalls and water filled pits. About 2,400 miles of streams do not meet water quality standards because of drainage from abandoned mines. There are uncounted households without an adequate water supply due to past mining practices. Mine fires and mine subsidence plague many Pennsylvania communities. The estimated cost to reclaim these past scars is over $15 billion. The beneficial use of coal ash in Pennsylvania for mine reclamation and mine drainage pollution abatement projects increased during the past ten years. The increase is primarily due to procedural and regulatory changes by the Department of Environmental Protection (DEP). Prior to 1986, DEP required a mining permit and a separate waste disposal permit for the use of coal ash in backfilling and reclaiming a surface mine site. In order to eliminate the dual permitting requirements and promote mine reclamation, procedural changes now allow a single permit which authorize both mining and the use of coal ash in reclaiming active and abandoned pits. The actual ash placement, however, must be conducted in accordance with the technical specifications in the solid waste regulations

  7. Stabilization of Rocky Flats combustible residues contaminated with plutonium metal and organic solvents

    International Nuclear Information System (INIS)

    Bowen, S.M.; Cisneros, M.R.; Jacobson, L.L.; Schroeder, N.C.; Ames, R.L.

    1998-01-01

    This report describes tests on a proposed flowsheet designed to stabilize combustible residues that were generated at the Rocky Flats Environmental Technology Site (RFETS) during the machining of plutonium metal. Combustible residues are essentially laboratory trash contaminated with halogenated organic solvents and plutonium metal. The proposed flowsheet, designed by RFETS, follows a glovebox procedure that includes (1) the sorting and shredding of materials, (2) a low temperature thermal desorption of solvents from the combustible materials, (3) an oxidation of plutonium metal with steam, and (4) packaging of the stabilized residues. The role of Los Alamos National Laboratory (LANL) in this study was to determine parameters for the low temperature thermal desorption and steam oxidation steps. Thermal desorption of carbon tetrachloride (CCl 4 ) was examined using a heated air stream on a Rocky Flats combustible residue surrogate contaminated with CCl 4 . Three types of plutonium metal were oxidized with steam in a LANL glovebox to determine the effectiveness of this procedure for residue stabilization. The results from these LANL experiments are used to recommend parameters for the proposed RFETS stabilization flowsheet

  8. 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.

  9. Mercury and halogens in coal--Their role in determining mercury emissions from coal combustion

    Science.gov (United States)

    Kolker, Allan; Quick, Jeffrey C.; Senior, Connie L.; Belkin, Harvey E.

    2012-01-01

    Mercury is a toxic pollutant. In its elemental form, gaseous mercury has a long residence time in the atmosphere, up to a year, allowing it to be transported long distances from emission sources. Mercury can be emitted from natural sources such as volcanoes, or from anthropogenic sources, such as coal-fired powerplants. In addition, all sources of mercury on the Earth's surface can re-emit it from land and sea back to the atmosphere, from which it is then redeposited. Mercury in the atmosphere is present in such low concentrations that it is not considered harmful. Once mercury enters the aquatic environment, however, it can undergo a series of biochemical transformations that convert a portion of the mercury originally present to methylmercury, a highly toxic organic form of mercury that accumulates in fish and birds. Many factors contribute to creation of methylmercury in aquatic ecosystems, including mercury availability, sediment and nutrient load, bacterial influence, and chemical conditions. In the United States, consumption of fish with high levels of methylmercury is the most common pathway for human exposure to mercury, leading the U.S. Environmental Protection Agency (EPA) to issue fish consumption advisories in every State. The EPA estimates that 50 percent of the mercury entering the atmosphere in the United States is emitted from coal-burning utility powerplants. An EPA rule, known as MATS (for Mercury and Air Toxics Standards), to reduce emissions of mercury and other toxic pollutants from powerplants, was signed in December 2011. The rule, which is currently under review, specifies limits for mercury and other toxic elements, such as arsenic, chromium, and nickel. MATS also places limits on emission of harmful acid gases, such as hydrochloric acid and hydrofluoric acid. These standards are the result of a 2010 detailed nationwide program by the EPA to sample stack emissions and thousands of shipments of coal to coal-burning powerplants. The United

  10. A study on the hydrotreating of coal hydro liquefaction residue and its kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.; Lu, X.; Zhang, D.; Gao, J. [Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai (China)

    2010-09-15

    Hydro-conversion of coal hydro liquefaction residue obtained from a 6 t/day pilot plant of Shenhua Group in Shanghai was carried out under the hydrotreating condition. The coal hydro liquefaction residue and its product were extracted in sequence with n-hexane, toluene and tetrahydrofuran in a Soxhlet apparatus. The n-hexane soluble fractions increased with the increase of reaction temperature and time. Its amount increased from 14.14% to a maximum of 40.86% under the conditions of 470 {sup o}C and 30 min, which meant that moderate extension of coal residence time in the coal hydro liquefaction reactor is beneficial to the increase of oil yield. A 4-lumped kinetic model of coal hydro liquefaction residue hydro-conversion was performed using solubility-based lumped fractions. In the model, the tetrahydrofuran insoluble fractions were classified into two parts: easily reactive part and unreactive part. The kinetic parameters were estimated by a fourth-order Runge-Kutta method and a nonlinear least squares method, and the apparent activation energies were calculated according to the Arrhenius Equation. A large quantity of total catalyst consisting of remained liquefaction catalyst, part of the mineral from raw coal and additive Fe-based catalyst could considerably reduce the apparent activation energy of hydro-conversion for the toluene insoluble/tetrahydrofuran insoluble fractions to 36.79 kJ-mol{sup -1}. The calculated values of the model coincided well with the experimental values. (authors)

  11. A Study on the Hydrotreating of Coal Hydroliquefaction Residue and its Kinetics

    Directory of Open Access Journals (Sweden)

    Jinsheng Gao

    2010-09-01

    Full Text Available Hydro-conversion of coal hydroliquefaction residue obtained from a 6t/day pilot plant of Shenhua Group in Shanghai was carried out under the hydrotreating condition. The coal hydroliquefaction residue and its product were extracted in sequence with n-hexane, toluene and tetrahydrofuran in a Soxhlet apparatus. The n-hexane soluble fractions increased with the increase of reaction temperature and time. Its amount increased from 14.14% to a maximum of 40.86% under the conditions of 470 °C and 30 min, which meant that moderate extension of coal residence time in the coal hydroliquefaction reactor is beneficial to the increase of oil yield. A 4-lumped kinetic model of coal hydroliquefaction residue hydro-conversion was performed using solubility-based lumped fractions. In the model, the tetrahydrofuran insoluble fractions were classified into two parts: easily reactive part and unreactive part. The kinetic parameters were estimated by a fourth-order Runge-Kutta method and a nonlinear least squares method, and the apparent activation energies were calculated according to the Arrhenius Equation. A large quantity of total catalyst consisting of remained liquefaction catalyst, part of the mineral from raw coal and additive Fe-based catalyst could considerably reduce the apparent activation energy of hydro-conversion for the toluene insoluble/tetrahydrofuran insoluble fractions to 36.79 kJ•mol-1. The calculated values of the model coincided well with the experimental values.

  12. Evaluation of thermal degradation of coal with residual salts

    Czech Academy of Sciences Publication Activity Database

    Plevová, Eva; Kaloč, M.; Šugárková, Věra; Vaculíková, Lenka; Vallová, S.

    2010-01-01

    Roč. 1, č. 1 (2010), s. 15-19 ISSN 0976-6294 R&D Projects: GA ČR GA105/08/1398; GA ČR GP105/07/P416 Institutional research plan: CEZ:AV0Z30860518 Keywords : chlorides * impregnation * coal Subject RIV: CA - Inorganic Chemistry

  13. CHAR CRYSTALLINE TRANSFORMATIONS DURING COAL COMBUSTION AND THEIR IMPLICATIONS FOR CARBON BURNOUT

    Energy Technology Data Exchange (ETDEWEB)

    ROBERT H. HURT

    1998-09-08

    temperatures approaching 3000 o C. For the measurement of temperature histories an optical diagnostic is being developed that offers sufficient spatial resolution to distinguish the sample temperature from the substrate temperature. The optical diagnostic is based on a CID camera, a high-power lens, and movable mirrors to projecting multiple, filtered images onto a single chip. Oxidation kinetics are measured on the heat treated samples by a nonisothermal TGA technique. Task 2 Thermal deactivation kinetics. The goal of this task is to quantify thermal char deactivation as a function of temperature history and parent coal, with an emphasis on inert environments at temperatures and times found in combustion systems. The results are to be cast in the form of deactivation kinetics useful for incorporation in combustion models. Task 3 Crystal structure characterization. Crystal structure characterization provides important insight into the mechanisms of thermal char deactivation, and the degree of crystalline transformations has shown a strong correlation with reactivity changes in recent combustion studies [Davis et al., 1992, Beeley et al., 1996]. This task seeks to improve our understanding of char carbon crystalline transformations under combustion conditions by analyzing a large set of HRTEM fringe images for a series of flame-generated chars whose reactivities have been previously reported [Hurt et al., 1995, Beeley et al., 1996]. As a first step, a new technique is being developed for the quantitative analysis of fringe images, extending previous work to allow measurement of a complete set of crystal structure parameters including mean layer size, mean stacking height, interlayer spacing, layer curvature, amorphous fraction, and degree of anisotropy. The resulting database will revealing, at a very fundamental level, the basic differences in char crystal structure due to parent coal rank and to temperature history in the range of interest to combustion systems.

  14. Co-gasification of coal and biomass: Synergy, characterization and reactivity of the residual char.

    Science.gov (United States)

    Hu, Junhao; Shao, Jingai; Yang, Haiping; Lin, Guiying; Chen, Yingquan; Wang, Xianhua; Zhang, Wennan; Chen, Hanping

    2017-11-01

    The synergy effect between coal and biomass in their co-gasification was studied in a vertical fixed bed reactor, and the physic-chemical structural characteristics and gasification reactivity of the residual char obtained from co-gasification were also investigated. The results shows that, conversion of the residual char and tar into gas is enhanced due to the synergy effect between coal and biomass. The physical structure of residual char shows more pore on coal char when more biomass is added in the co-gasification. The migration of inorganic elements between coal and biomass was found, the formation and competitive role of K 2 SiO 3 , KAlSiO 4 , and Ca 3 Al 2 (SiO 4 ) 3 is a mechanism behind the synergy. The graphization degree is enhanced but size of graphite crystallite in the residual char decreases with biomass blending ratio increasing. TGA results strongly suggest the big difference in the reactivity of chars derived from coal and biomass in spite of influence from co-gasification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Modelling NO[sub x] formation in coal particle combustion at high temperature: an investigation of the devolatilisation kinetic factors

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.M.; Patterson, P.M.; Pourkashanian, M.; Williams, A.; Arenillas, A.; Rubiera, F.; Pis, J.J. (University of Leeds, Leeds (United Kingdom). Dept. of Fuel and Energy)

    1999-08-01

    Coal combustion computational fluid dynamic (CFD) models are a powerful predictive tool in combustion research. In existing coal combustion CFD models, the process is described by three kinetic rates: coal devolatilizaton, volatile combustion and char combustion. A general, representative devolatilisation rate for coal is a matter of some contention, and measured rates depend upon the type of experimental system employed in their determination. Thus the reported rates vary considerably, causing difficulties in the choice of rate expression for CFD modelling applications. In this investigation, a laminar flow CFD model of a drop-tube furnace was used to assess the influence of global devolatilisation rates on overall combustion behaviour, and in particular, NOx emissions. The rates chosen include some of the common expressions employed by researchers in the field. Analysis, and comparison of the modelling results with those of the experimental indicated that a single-step devolatilisation rate can give satisfactory profiles. This rate can be calculated from the tar release rate using a network model such as FG-DVC (functional group, depolymerisation, vaporisation and cross-linking) together with the nitrogen partitioning between gas and char during pyrolysis. The use of these single-step models result in good predictions of NOx, and the inclusion of soot/NOx interactions can improve the mode significantly to give an excellent agreement with experimental results. 2 refs., 4 figs., 3 tabs.

  16. Production of fines during co-combustion of coal with biomass fuels by fragmentation and attrition

    Energy Technology Data Exchange (ETDEWEB)

    I. Gulyurtlu; D. Boavida; H. Lopes (and others) [DEECA-INETI, Lisbon (Portugal)

    2005-07-01

    Results are reported from a project funded by the RFCS Programme of the European Union. The aim is to investigate, experimentally and by modeling, the production of fine char and ash particles during co-combustion of coal with wastes and biofuels in circulating fluidized bed. Work was undertaken at installations of different scales. Polish and Colombian coals were base fuels. The additional fuels were two sewage sludges. Bed temperature, feeding system, sand particle size, devolatilisation behaviour and char burn-out were studied to verify their influence on the fine particle production. Modeling was also carried out to understand the mechanisms of fragmentation and attrition. Samples from bed and cyclone were collected to determine particle size distributions. 11 refs.

  17. Some aspects of emission and volatization of trace elements on coal combustion

    International Nuclear Information System (INIS)

    Sanchez, J.C.D.; Formoso, M.L.L.; Bristoti, A.

    1987-01-01

    The present research work was carried out an industrial plant which uses a mixture of coals from Leao and Recreio mines for steam generation in a bioler with a capacity of 160t/h of steam. Coal samples from Leao, Recreio and the correspondent mixture were taken, as well as samples from the products of combustion. The present study fundamentally aims at assessing the emission of trace elements and major components of mineral matter, present in coal, in order to bring subsidies for a more efficient control over atmospheric, terrestrial and water pollution. Emissions of trace elements: As, B, Be, Cd, Cl, Co, Cr, Cu, F, Ga, Hg, Mn, Mo, Ni, Pb, S, Sn, V, Zn, Zr, and major elements: Si, Al, Ca, Mg, Ti, Fe, K and P, were calculated. Moreover, the average emission of particulate matter to the atmosphere was evaluated. In the present work, analytical procedures as X-ray spectroscopy and absorption spectroscopy and techniques used for the determination of F and Cl in Brazilian coals are cited. (author) [pt

  18. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bradley R. [Univ. of Utah, Salt Lake City, UT (United States); Fry, Andrew R. [Univ. of Utah, Salt Lake City, UT (United States); Senior, Constance L. [Univ. of Utah, Salt Lake City, UT (United States); Shim, Hong Shig [Univ. of Utah, Salt Lake City, UT (United States); Otten, Brydger Van [Univ. of Utah, Salt Lake City, UT (United States); Wendt, Jost [Univ. of Utah, Salt Lake City, UT (United States); Shaddix, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tree, Dale [Brigham Young Univ., Provo, UT (United States)

    2010-06-01

    This report summarizes Year 2 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Year 2 focused extensively on obtaining experimental data from the bench-scale, lab-scale and pilot-scale reactors. These data will be used to refine and validate submodels to be implemented in CFD simulations of full-scale boiler retrofits. Program tasks are on schedule for Year 3 completion. Both Year 2 milestones were completed on schedule and within budget.

  19. Transformations of inorganic coal constituents in combustion systems. Volume 3, Appendices: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Helble, J.J. [ed.; Srinivasachar, S.; Wilemski, G.; Boni, A.A. [PSI Technology Co., Andover, MA (United States); Kang, Shim-Gyoo; Sarofim, A.F.; Graham, K.A.; Beer, J.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Peterson, T.W.; Wendt, O.L.; Gallagher, N.B.; Bool, L. [Arizona Univ., Tucson, AZ (United States); Huggins, F.E.; Huffman, G.P.; Shah, N.; Shah, A. [Kentucky Univ., Lexington, KY (United States)

    1992-11-01

    This report contains the computer codes developed for the coal combustion project. In Subsection B.1 the FORTRAN code developed for the percolative fragmentation model (or the discrete model, since a char is expressed as a collection of discrete elements in a discrete space) is presented. In Subsection B.2 the code for the continuum model (thus named because mineral inclusions are distributed in a continuum space) is presented. A stereological model code developed to obtain the pore size distribution from a two-dimensional data is presented in Subsection B.3.

  20. Deposit Formation during Coal-Straw Co-Combustion in a Utility PF-Boiler

    DEFF Research Database (Denmark)

    Andersen, Karin Hedebo

    1998-01-01

    the combustion conditions, including the method of introduction of the straw to the boiler, as well as the amount of Fe introduced as Pyrite with the coal.No significant effect could be found in the deposition probe samples for an increase in probe metal temperature from 540°C to 620°C. The importance of deposit...... area. The evaluation was performed for an opposed-wall fired and tangentially fired boiler, which are compared to the wall-fired MKS1. Two major aspects were evaluated: The effect of flue gas temperatures and the effect of mixing. However, no final recommandation for choise of boilertype can be given...

  1. Numerical study of aerodynamics and brown coal combustion in the vortex furnace with air excess variation

    Directory of Open Access Journals (Sweden)

    Krasinsky Denis

    2017-01-01

    Full Text Available The results of numerical modelling of 3D turbulent two-phase reacting flow with account for all the principal heat and mass transfer processes during the pulverized brown coal combustion in the vortex furnace of a power plant boiler unit have been presented. For two computational cases where air excess coefficient α was varied (set to 1.15 and 1.25, the detailed aerothermochemical 3D structure of reacting flow in the furnace volume has been revealed. The comparison of integral heat engineering parameters and NOx emissions obtained in the two cases has shown a slightly improved vortex furnace performance in the case α=1.25.

  2. Health Effects of Subchronic Inhalation of Simulated Downwind Coal Combustion Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Joe Mauderly

    2009-01-07

    The purpose of this project was to conduct a comprehensive laboratory-based evaluation of selected respiratory and cardiac health hazards of subchronic (up to 6 months) inhalation of simulated key components of 'downwind plume' emissions of coal combustion. This project was performed as an integral part of a joint government-industry program termed the 'National Environmental Respiratory Center' (NERC), which is aimed at disentangling the roles of different physical-chemical air pollutants and their sources in the health effects associated statistically with air pollution. The characterization of the exposure atmosphere and the health assays were identical to those employed in the NERC protocols used to evaluate other pollution source emissions, such as diesel, gasoline, and wood combustion. The project had two phases, each encompassing multiple tasks. Guidelines for the composition of the exposure atmosphere were set by consensus of an expert workshop. Development of the capability to generate the exposure atmosphere and pilot studies of the comparative exposure composition using two coal types were accomplished in Phase 1. In Phase 2, the toxicological study was conducted using Powder River Basin Sub-bituminous coal. NETL provided 50% support for the work in Phase 1 and had intended to provide 20% support for the work in Phase 2. Phase 1 is completed and Phase 2 is in the final stages. All animal exposures were completed without incident, and the composition of the exposure atmospheres met the targets. All of the health sample collections are completed, but some samples remain to be analyzed. Data summaries and final statistical analysis of results remain to be completed. The goal is to submit all publications before the end of FY-08. Repeated exposure to simulated downwind coal emissions caused some significant health effects, but the number of effects tended to be fewer than those caused by the other NERC exposures (diesel and gasoline

  3. Analysis of oxy-fuel combustion power cycle utilizing a pressurized coal combustor

    International Nuclear Information System (INIS)

    Hong, Jongsup; Chaudhry, Gunaranjan; Brisson, J.G.; Field, Randall; Gazzino, Marco; Ghoniem, Ahmed F.

    2009-01-01

    Growing concerns over greenhouse gas emissions have driven extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology in which fuels are burned in an environment of oxygen and recycled combustion gases. In this paper, an oxy-fuel combustion power cycle that utilizes a pressurized coal combustor is analyzed. We show that this approach recovers more thermal energy from the flue gases because the elevated flue gas pressure raises the dew point and the available latent enthalpy in the flue gases. The high-pressure water-condensing flue gas thermal energy recovery system reduces steam bleeding which is typically used in conventional steam cycles and enables the cycle to achieve higher efficiency. The pressurized combustion process provides the purification and compression unit with a concentrated carbon dioxide stream. For the purpose of our analysis, a flue gas purification and compression process including de-SO x , de-NO x , and low temperature flash unit is examined. We compare a case in which the combustor operates at 1.1 bars with a base case in which the combustor operates at 10 bars. Results show nearly 3% point increase in the net efficiency for the latter case.

  4. Staged combustion - main method for suppressing nitrogen oxides in pulverized-coal fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R. (Vsesoyuznyi Teplotekhnicheskii Institut (USSR))

    1989-08-01

    Describes principles behind staged combustion, which is based on organizing furnace operations so that only part of the air from the fuel is taken into the furnace. The remaining air, which is needed for combustion, is fed as a tertiary blast jet into the intermediate flame zone. Following inflammation and combustion of the volatile matter, the oxygen concentration in the flame drops sharply causing a retardation of the oxidation reactions forming NO and an intensification of the reactions causing the nitrogen-containing radicals NH{sub i} and CN to be converted into N{sub 2}. When the reducing agents CO, H{sub 2} and CH{sub 4} are present in certain flame zones, even the nitrogen oxide is reduced to N{sub 2}. The NO concentrations in the flame are reduced until the jet of tertiary air is introduced. Discusses with reference to practice in the USA and Western Europe how to achieve maximum effect of this method for different types of boiler and presents the results of observations of the introduction of staged combustion to the BKZ-210-140 boiler burning Kuznetsk gassy coal. 5 refs.

  5. Optimization of pulverised coal combustion by means of CFD/CTA modeling

    Directory of Open Access Journals (Sweden)

    Filkoski Risto V.

    2006-01-01

    Full Text Available The objective of the work presented in this paper was to apply a method for handling two-phase reacting flow for prediction of pulverized coal combustion in large-scale boiler furnace and to assess the ability of the model to predict existing power plant data. The paper presents the principal steps and results of the numerical modeling of power boiler furnace with tangential disposition of the burners. The computational fluid dynamics/computational thermal analysis (CFD/CTA approach is utilized for creation of a three-dimensional model of the boiler furnace, including the platen superheater in the upper part of the furnace. Standard k-e model is employed for description of the turbulent flow. Coal combustion is modeled by the mixture fraction/probability density function approach for the reaction chemistry, with equilibrium assumption applied for description of the system chemistry. Radiation heat transfer is computed by means of the simplified P-N model, based on the expansion of the radiation intensity into an orthogonal series of spherical harmonics. Some distinctive results regarding the examined boiler performance in capacity range between 65 and 95% are presented graphically. Comparing the simulation predictions and available site measurements concerning temperature, heat flux and combustion efficiency, a conclusion can be drawn that the model produces realistic insight into the furnace processes. Qualitative agreement indicates reasonability of the calculations and validates the employed sub-models. After the validation and verification of the model it was used to check the combustion efficiency as a function of coal dust sieve characteristics, as well as the impact of burners modification with introduction of over fire air ports to the appearance of incomplete combustion, including CO concentration, as well as to the NOx concentration. The described case and other experiences with CFD/CTA stress the advantages of numerical modeling and

  6. Morphology, composition, and mixing state of primary particles from combustion sources ? crop residue, wood, and solid waste

    OpenAIRE

    Liu, Lei; Kong, Shaofei; Zhang, Yinxiao; Wang, Yuanyuan; Xu, Liang; Yan, Qin; Lingaswamy, A. P.; Shi, Zongbo; Lv, Senlin; Niu, Hongya; Shao, Longyi; Hu, Min; Zhang, Daizhou; Chen, Jianmin; Zhang, Xiaoye

    2017-01-01

    Morphology, composition, and mixing state of individual particles emitted from crop residue, wood, and solid waste combustion in a residential stove were analyzed using transmission electron microscopy (TEM). Our study showed that particles from crop residue and apple wood combustion were mainly organic matter (OM) in smoldering phase, whereas soot-OM internally mixed with K in flaming phase. Wild grass combustion in flaming phase released some Cl-rich-OM/soot particles and cardboard combusti...

  7. 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.

  8. Development and Testing of Industrial Scale Coal Fired Combustion System, Phase 3

    Energy Technology Data Exchange (ETDEWEB)

    Bert Zauderer

    1998-09-30

    Coal Tech Corp's mission is to develop, license & sell innovative, lowest cost, solid fuel fired power systems & total emission control processes using proprietary and patented technology for domestic and international markets. The present project 'DEVELOPMENT & TESTING OF INDUSTRIAL SCALE, COAL FIRED COMBUSTION SYSTEM, PHASE 3' on DOE Contract DE-AC22-91PC91162 was a key element in achieving this objective. The project consisted of five tasks that were divided into three phases. The first phase, 'Optimization of First Generation 20 MMBtu/hr Air-Cooled Slagging Coal Tech Combustor', consisted of three tasks, which are detailed in Appendix 'A' of this report. They were implemented in 1992 and 1993 at the first generation, 20 MMBtu/hour, combustor-boiler test site in Williamsport, PA. It consisted of substantial combustor modifications and coal-fired tests designed to improve the combustor's wall cooling, slag and ash management, automating of its operation, and correcting severe deficiencies in the coal feeding to the combustor. The need for these changes was indicated during the prior 900-hour test effort on this combustor that was conducted as part of the DOE Clean Coal Program. A combination of combustor changes, auxiliary equipment changes, sophisticated multi-dimensional combustion analysis, computer controlled automation, and series of single and double day shift tests totaling about 300 hours, either resolved these operational issues or indicated that further corrective changes were needed in the combustor design. The key result from both analyses and tests was that the combustor must be substantially lengthened to maximize combustion efficiency and sharply increase slag retention in the combustor. A measure of the success of these modifications was realized in the third phase of this project, consisting of task 5 entitled: 'Site Demonstration with the Second Generation 20 MMBtu/hr Air-Cooled Slagging Coal Tech

  9. Shea meal and cotton stalk as potential fuels for co-combustion with coal.

    Science.gov (United States)

    Munir, S; Nimmo, W; Gibbs, B M

    2010-10-01

    The efficient management of waste biomass is an important environmental problem in agricultural countries. Often land-fill is the main disposal route with ramifications including CH(4) release having 21 times greater global warming potential per molecule than CO(2). Biomasses are considered to be CO(2)-neutral fuels when combusted. Moreover, they are renewable and covered by the renewable obligation scheme and eligible for certificates in the UK. The overall objective of the investigation is to assess the performance of selected biomass and coal co-firing under two different modes of operation, air-staging and fuel-staging with the benefit of reduced-NO(x) and SO(2) emissions in power plant. The biomasses chosen for the study, shea meal (SM) and cotton stalk (CS) have very different cellulose/lignin compositions and different reported thermal behaviour. A series of experiments have been carried out in a 20 kW, down fired combustor using coal, shea meal-coal and cotton stalk-coal blends under un-staged, air-staged and fuel-staged co-combustion configurations. For air-staging, an optimum value of primary zone stoichiometry SR(1)=0.9 was found. Keeping it fixed, the shea meal and cotton stalk content in the coal-biomass blends was set to 5%, 10% and 15% on thermal basis. NO reductions of 51% and 60% were achieved using SM and CS, respectively, with an optimum thermal biomass blending ratio (BBR) of 10%. The results obtained were compared with un-staged and air-staged results for coal without the addition of biomass. Similarly for fuel-staging, keeping the length of the reburn and burnout zone fixed, SM and CS were evaluated as reductive fuel using different reburn fuel fractions (R(ff)) of 5%, 10%, 15% and 20%. NO reductions of 83% and 84% were obtained with an optimum R(ff) of 15% with an optimum reburn zone stoichiometry of SR(2)=0.8 for both SM and CS, respectively. SO(2) reduction and char burnout efficiency were also evaluated. It was found that addition of

  10. The Method of Validity Evaluation of Hard Coal Excavation in Residual Seam Parts

    Science.gov (United States)

    Wodarski, Krzysztof; Bijańska, Jolanta; Gumiński, Adam

    2017-12-01

    The excavation of residual seam parts should be justified by positive assessment of the purposefulness, technical feasibility and economic effectiveness. The results of the profitability evaluation are crucial in a decision making process. The excavation of residual seam parts, even if it is possible from a technical point of view, should not be implemented if it is economically inefficient or when accompanied by a very high risk of non-recovery of invested capital resources. The article presents the evaluation method of possibilities of excavating hard coal from residual seam parts, and the example of its use in one of collieries in the Upper Silesian Coal Basin. Working in line with the developed method, allows to indicate the variant of residual seam part exploitation, which is feasible to implement from a technical point of view, and which is characterized by the highest economic effectiveness and lowest risk.

  11. Residual subsidence analysis after the end of coal mine work. Example from Lorraine Colliery, France

    International Nuclear Information System (INIS)

    Al Heib, M.; Nicolas, M.; Noirel, J.F.; Wojtkowiak, F.

    2005-01-01

    This paper describes the residual movements associated with the deep coal mines. The studied case relates to works located into Lorraine coal basin. The paper is divided into two sections. The first one describes subsidence phenomena, especially the residual phase in terms of amplitude, duration and localization. The second one focus on Morsbach case: the total and residual subsidence measurements will be analyzed and compared to the state of the art as well as the currant knowledge. The results of the analysis show that the duration of residual movements does not exceed 24 months and their amplitude is about 5% of total subsidence. We analyze also the declarations of the mining damage during and after the mining period. Damages occur, after this period are probably due to late observations. (authors)

  12. Preliminary assessment of the health and environmental impacts of fluidized-bed combustion of coal as applied to electrical utility systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-02-01

    The objective of this study was to assess the health and environmental impacts of fluidized-bed combustion of coal (FBC), specifically as applied to base-load generation of electrical energy by utilities. The public health impacts of Fluidized-Bed Combustion (FBC) plants are expected to be quite similar to those for Low Sulfur Coal (LSC) and Flue Gas Desulfurization (FGD) plants because all appear to be able to meet Federal emission standards; however, there are emissions not covered by standards. Hydrocarbon emissions are higher and trace element emissions are lower for FBC than for conventional technologies. For FBC, based on an analytical model and a single emission data point, the polycyclic organic material decreases the anticipated lifespan of the highly exposed public very slightly. Added health protection due to lower trace element emissions is not known. Although there is a large quantity of solid wastes from the generating plant, the environmental impact of the FBC technology due to solid residue appears lower than for FGD, where sludge management requires larger land areas and presents problems due to the environmentally noxious calcium sulfite in the waste. Fixing the sludge may become a requirement that increases the cost of wet-limestone FGD but makes that system more acceptable. The potential for aquatic or terrestrial impacts from hydrocarbon emissions is low. If application of AFBC technology increases the use of local high-sulfur coals to the detriment of western low-sulfur coal, a sociological benefit could accrue to the FBC (or FGD) technology, because impacts caused by western boom towns would decrease. The infrastructure of areas that mine high-sulfur coal in the Midwest are better equipped to handle increased mining than the West.

  13. Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David

    2013-09-30

    The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

  14. Numerical study on NO formation in a pulverized coal-fired furnace using oxy-fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Aiyue; Chen, Yuan; Sheng, Changdong [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Computational fluid dynamics (CFD) approach was employed to numerically investigate NO formation in a 600 MW wall-fired pulverized coal-fired furnace retrofitted for oxy-coal combustion, aimed at the impacts of flue gas recycle ratio, O{sub 2} staging and recycled NO with the recycled flue gas (RFG) on NO formation and emission. An in-house CFD research code for conventional air combustion was developed and extended to simulate O{sub 2}/RFG combustion with specific considerations of the change of gas properties and its impact on coal particle combustion processes. The extended De Soete mechanisms including NO reburning mechanism were applied to describe transformations of fuel nitrogen. It was shown that CFD simulation represented the significant reduction of NO formation during O{sub 2}/RFG combustion compared to that during air combustion. The in-burner and particularly the in-furnace O{sub 2} staging were confirmed still to play very important roles in NO formation control. Changing the recycle ratio had significant impact on the combustion performance and consequently on NO formation and emission. With the combustion performance ensured, decreasing the flue gas recycle ratio or increasing the inlet O{sub 2} concentration of combustion gas led to reduction of NO formation and emission. Although NO formation and emission was found to increase with increasing the inlet NO concentration of combustion gas, CFD simulation indicated that {proportional_to}74% of the inlet NO was reduced in the furnace, consistent with the experimental data reported in the literature. This demonstrated the significant contribution of reburning mechanism to the reduction of the recycled NO in the furnace.

  15. Polycyclic aromatic hydrocarbons and organic matter associated to particulate matter emitted from atmospheric fluidized bed coal combustion

    International Nuclear Information System (INIS)

    Mastral, A.M.; Callen, M.S.; Garcia, T.

    1999-01-01

    The polycyclic aromatic hydrocarbons (PAH) and the organic matter (OM) content associated with particulate matter (PM) emissions from atmospheric fluidized bed coal combustion have been studied. The two main aims of the work have been (a) to study OM and PAH emissions as a function of the coal fluidized bed combustion (FBC) variables in solid phase and (b) to check if there is any correlation between OM and PAH contained in the PM. The combustion was carried out in a laboratory scale plant at different combustion conditions: temperature, percentage of oxygen excess, and total air flow. PAH associated on the particulate matter have been analyzed by fluorescence spectroscopy in the synchronous mode (FS) after PM extraction by sonication with dimethylformamide (DMF). It can be concluded that there is not a direct relationship between the OM content and the PAH supported in the PM emitted. In addition, neither PM or OM show dependence between themselves

  16. 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.

  17. The comparative analysis of heat transfer efficiency in the conditions of formation of ash deposits in the boiler furnaces, with taking into account the crystallization of slag during combustion of coal and water-coal fuel

    Science.gov (United States)

    Salomatov, V. V.; Kuznetsov, G. V.; Syrodoy, S. V.

    2017-11-01

    The results of the numerical simulation of heat transfer from the combustion products of coal and coal-water fuels (CWF) to the internal environment. The mathematical simulation has been carried out on the sample of the pipe surfaces of the combustion chamber of the boiler unit. The change in the characteristics of heat transfer (change of thermochemical characteristics) in the conditions of formation of the ash deposits have been taken into account. According to the results of the numerical simulation, the comparative analysis of the efficiency of heat transfer has been carried out from the furnace environment to the inside pipe coolant (water, air, or water vapor) from the combustion of coal and coal-water fuels. It has been established that, in the initial period of the boiler unit operation during coal fuel combustion the efficiency of heat transfer from the combustion products of the internal environment is higher than when using CWF. The efficiency of heat transfer in CWF combustion conditions is more at large times (τ≥1.5 hours) of the boiler unit. A significant decrease in heat flux from the combustion products to the inside pipe coolant in the case of coal combustion compared to CWF has been found. It has been proved that this is due primarily to the fact that massive and strong ash deposits are formed during coal combustion.

  18. The atomization and the flame structure in the combustion of residual fuel oils; La atomizacion y estructura de flama en la combustion de combustibles residuales

    Energy Technology Data Exchange (ETDEWEB)

    Bolado Estandia, Ramon [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    In this article a research on the combustion of heavy residual fuel oils is presented. The type of flames studied were obtained by means of the burning of sprays produced by an atomizer designed and calibrated specially for the research purpose. The flame characteristics that were analyzed are its length, its luminosity, the temperature, the distribution of the droplets size and mainly the burning regime of the droplets in the flame. The experimental techniques that were used for these studies were shadow micro-photography, suction pyrometry and of total radiation, laser diffraction, 35 mm photography, and impact push. The analysis of the experimental results, together with the results of the application of a mathematical model, permitted to establish two parameters, that quantitatively related determine the burning regime of the droplets in a flame of sprays of residual heavy fuel oil. [Espanol] En este articulo se presenta una investigacion sobre la combustion de combustibles residuales pesados. El tipo de flamas estudiadas se obtuvieron mediante el quemado de sprays producidos por un atomizador disenado y calibrado especialmente para el proposito de la investigacion. Las caracteristicas de flama que se analizaron son la longitud, la luminosidad, la temperatura, la distribucion de tamano de gotas y, principalmente, el regimen de quemado de gotas en la flama. Las tecnicas experimentales que se usaron para estos estudios fueron microfotografia de sombras, pirometria de succion y de radiacion total, difraccion laser, fotografia de 35 mm y empuje de impacto. El analisis de resultados experimentales, junto con los resultados de la aplicacion de un modelo matematico, permitio establecer dos parametros, que relacionados cuantitativamente, determinan el regimen de quemado de gotas en una flama de sprays de combustible residual pesado.

  19. The atomization and the flame structure in the combustion of residual fuel oils; La atomizacion y estructura de flama en la combustion de combustibles residuales

    Energy Technology Data Exchange (ETDEWEB)

    Bolado Estandia, Ramon [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1985-12-31

    In this article a research on the combustion of heavy residual fuel oils is presented. The type of flames studied were obtained by means of the burning of sprays produced by an atomizer designed and calibrated specially for the research purpose. The flame characteristics that were analyzed are its length, its luminosity, the temperature, the distribution of the droplets size and mainly the burning regime of the droplets in the flame. The experimental techniques that were used for these studies were shadow micro-photography, suction pyrometry and of total radiation, laser diffraction, 35 mm photography, and impact push. The analysis of the experimental results, together with the results of the application of a mathematical model, permitted to establish two parameters, that quantitatively related determine the burning regime of the droplets in a flame of sprays of residual heavy fuel oil. [Espanol] En este articulo se presenta una investigacion sobre la combustion de combustibles residuales pesados. El tipo de flamas estudiadas se obtuvieron mediante el quemado de sprays producidos por un atomizador disenado y calibrado especialmente para el proposito de la investigacion. Las caracteristicas de flama que se analizaron son la longitud, la luminosidad, la temperatura, la distribucion de tamano de gotas y, principalmente, el regimen de quemado de gotas en la flama. Las tecnicas experimentales que se usaron para estos estudios fueron microfotografia de sombras, pirometria de succion y de radiacion total, difraccion laser, fotografia de 35 mm y empuje de impacto. El analisis de resultados experimentales, junto con los resultados de la aplicacion de un modelo matematico, permitio establecer dos parametros, que relacionados cuantitativamente, determinan el regimen de quemado de gotas en una flama de sprays de combustible residual pesado.

  20. Analysis of briquetting process of sewage sludge with coal to combustion process

    Directory of Open Access Journals (Sweden)

    Kosturkiewicz Bogdan

    2016-01-01

    Full Text Available Energy recovery from sewage sludge can be achieved by several thermal technologies, but before those processes sewage sludge requires special pretreatment. The paper presents the investigation of the sewage sludge with coal briquettes as a fuel for combustion process. Research is conducted at Department of Manufacturing Systems and Department of Thermal Engineering and Environmental Protection, AGH University of Science and Technology to develop a technology of briquette preparation. The obtained results showed possibility of briquetting of municipal sewage sludge with coal in roll presses, equipped with asymmetric thickening gravity feed system. The following properties were determined for the obtained briquettes: density, drop strength and compressive strength. Based on physical and chemical analysis of prepared briquettes it was confirmed that briquettes have good fuel properties to combustion process. Thermal behaviour of studied sewage sludge and prepared mixture was investigated by thermogravimetric analysis (TG. For the thermo gravimetric analysis (TG the samples were heated in an alumina crucible from an ambient temperature up to 1000 °C at a constant rates: 10 °C/min, 40 °C/min and 100 °C/min in a 40 ml/min flow of air.

  1. Co-Combustion of Municipal Sewage Sludge and Hard Coal on Fluidized Bed Boiler WF-6

    Directory of Open Access Journals (Sweden)

    Rajczyk Rafał

    2014-12-01

    Full Text Available According to data of the Central Statistical Office, the amount of sludge produced in municipal wastewater treatment plants in 2010 amounted to 526000 Mg d.m. The forecast of municipal sewage sludge amount in 2015 according to KPGO2014 will reach 642400 Mg d.m. and is expected to increase in subsequent years. Significant amounts of sludge will create problems due to its utilization. In order to solve this problem the use of thermal methods for sludge utilization is expected. According to the National Waste Management Plan nearly 30% of sewage sludge mass should be thermally utilized by 2022. The article presents the results of co-combustion of coal and municipal sewage sludge in a bubbling fluidized bed boiler made by SEFAKO and located in the Municipal Heating Company in Morag. Four tests of hard coal and sewage sludge co-combustion have been conducted. Boiler performance, emissions and ash quality were investigated.

  2. Application study of Bio-FGD based on environmental safety during the coal combustion

    Science.gov (United States)

    Zhang, Pin

    2018-05-01

    Coal combustion produces a large amount of acidic gas, which is the main cause of acid rain and other natural disasters. Flue Gas Desulfurization (FGD) is a necessary requirement for clean coal combustion. Compared with the traditional chemical desulfurization technology, biological desulfurization has the advantages of low operating cost, without secondary pollution, low carbon emission and the additional economic benefits. The process and structure of BioDeSOx which as one of Bio-FGD technology is introduced. The major factors that influent BioDeSOx Bio- FGD system is the pH, oxidation reduction potential (-300 MV to -400MV), electrical conductivity, the adding amount of nutrient and temperature (30°C-40°C). Taking the Bio- FGD project of Yixing xielian thermal power plant as an example, the BioDeSOx technology was applied in this project. The environmental and economic benefits of the project were greater than the traditional desulfurization technology. With the continuous improvement of environmental safety standards, Bio- FGD technology will have broad application prospects.

  3. The application of zonal trademark combustion monitoring and tuning system to coal boilers for efficiency improvement and emissions reduction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Guang; Zhou, Wei; Widmer, Neil C.; Moyeda, David K. [GE Energy, Irvine, CA (United States)

    2013-07-01

    Coal-fired boilers equipped with Low NO{sub x} Burner (LNB) and Overfire Air (OFA) are challenged with maintaining good combustion conditions. In many cases, the significant increases in carbon monoxide (CO) and unburned carbon levels can be attributed to local poor combustion conditions as a result of poorly controlled fuel-air distribution within the furnace. The Zonal trademark combustion monitoring and tuning system developed by GE is available to detect and correct the furnace air-fuel distribution imbalance. The system monitors the boiler excess oxygen (O{sub 2}) and combustible gases, primarily carbon monoxide (CO), by using spatially distributed multipoint sensors located in the boiler's high temperature upper convective backpass region. At these locations, the furnace flow is still significantly stratified allowing tracing of poor combustion zones to specific burners and OFA ports. Using a model-based tuning system, operators can rapidly respond to poor combustion conditions by redistributing airflows to select burners and OFA ports. By improving combustion at every point within the furnace, the boiler can operate at reduced excess O{sub 2} and reduced furnace exit gas temperature (FEGT) while also reducing localized hot spots, corrosive gas conditions, slag formation, and carbon-in-ash. Benefits include improving efficiency, reducing NO{sub X} emissions, increasing output and maximizing availability. This chapter presents the results from implementing the Zonal combustion monitoring and tuning system on a 460 MW tangential-fired coal boiler in the Western United States.

  4. Process from removing benzine, toluene, etc. , from petroleum residues, coal tar, and shale tar, etc

    Energy Technology Data Exchange (ETDEWEB)

    Hlawaty, F

    1888-08-11

    A process is described for the preparation of ligroin and its homologs as well as naphthalene and anthracene consisting in leading superheated water vapor into a mixture of petroleum residues (or mineral coal tar, etc.) heated to about 400/sup 0/C with cellulosic substances as sage shreds, sea grass, or straw, with addition of caustic alkali.

  5. Characterization of Oxy-combustion Impacts in Existing Coal-fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Bradley Adams; Andrew Fry; Constance Senior; Hong Shim; Huafeng Wang; Jost Wendt; Christopher Shaddix

    2009-06-30

    This report summarizes Year 1 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Through the course of Year 1 activities, great progress was made toward understanding the issues associated with oxy-combustion retrofit of coal-fired boilers. All four Year 1 milestones and objectives have been, or will be, completed on schedule and within budget. Progress in the four milestone areas may be summarized as follows: • University of Utah has performed size segregated ash composition measurements in the Oxy-Fuel Combustor (OFC). These experiments indicate that oxy-combustion retrofit may impact ash aerosol mineral matter composition. Both flame temperature and flue gas composition have been observed to influence the concentration of calcium, magnesium and iron in the fine particulate. This could in turn impact boiler fouling and slagging. • Sandia National Labs has shown that char oxidation rate is dependent on particle size (for sizes between 60 and 100 microns) by performing fundamental simulations of reacting char particles. These predictions will be verified by making time-resolved optical measurements of char particle temperature, velocity and size in bench-scale experiments before the end of Year 1. • REI and Siemens have completed the design of an oxy-research burner that will be mounted on University of Utah’s pilot-scale furnace, the L1500. This burner will accommodate a wide range of O2, FGR and mixing strategies under conditions relevant for utility boiler operation. Through CFD modeling of the different burner designs, it was determined that the key factor influencing flame stabilization location is particle heat-up rate. The new oxy-research burner and associated equipment is scheduled for delivery before the end of Year 1. • REI has completed a literature survey of slagging and

  6. Trace element emissions from spontaneous combustion of gob piles in coal mines, Shanxi, China

    Science.gov (United States)

    Zhao, Y.; Zhang, Jiahua; Chou, C.-L.; Li, Y.; Wang, Z.; Ge, Y.; Zheng, C.

    2008-01-01

    The emissions of potentially hazardous trace elements from spontaneous combustion of gob piles from coal mining in Shanxi Province, China, have been studied. More than ninety samples of solid waste from gob piles in Shanxi were collected and the contents of twenty potentially hazardous trace elements (Be, F, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sn, Sb, Hg, Tl, Pb, Th, and U) in these samples were determined. Trace element contents in solid waste samples showed wide ranges. As compared with the upper continental crust, the solid waste samples are significantly enriched in Se (20x) and Tl (12x) and are moderately enriched in F, As, Mo, Sn, Sb, Hg, Th, and U (2-5x). The solid waste samples are depleted in V, Cr, Mn, Co, Ni, Cu, and Zn. The solid waste samples are enriched in F, V, Mn, Cr, Co, Ni, Cu, Zn, Sb, Th, and U as compared with the Shanxi coals. Most trace elements are higher in the clinker than in the unburnt solid waste except F, Sn, and Hg. Trace element abundances are related to the ash content and composition of the samples. The content of F is negatively correlated with the ash content, while Pb is positively correlated with the ash. The concentrations of As, Mn, Zn, and Cd are highly positively correlated with Fe2O3 in the solid waste. The As content increases with increasing sulfur content in the solid waste. The trace element emissions are calculated for mass balance. The emission factors of trace elements during the spontaneous combustion of the gobs are determined and the trace element concentrations in the flue gas from the spontaneous combustion of solid waste are calculated. More than a half of F, Se, Hg and Pb are released to the atmosphere during spontaneous combustion. Some trace element concentrations in flue gas are higher than the national emission standards. Thus, gob piles from coal mining pose a serious environmental problem. ?? 2007 Elsevier B.V. All rights reserved.

  7. Renew, reduce or become more efficient? The climate contribution of biomass co-combustion in a coal-fired power plant

    International Nuclear Information System (INIS)

    Miedema, Jan H.; Benders, René M.J.; Moll, Henri C.; Pierie, Frank

    2017-01-01

    Highlights: • Coal mining is more energy and CO_2 efficient than biomass production. • Co-combustion of 60% biomass with coal doubles mass transport compared to 100% coal. • Low co-combustion levels reduce GHG emissions, but the margins are small. • Total supply chain efficiency is the highest for the coal reference at 41.2%. - Abstract: Within this paper, biomass supply chains, with different shares of biomass co-combustion in coal fired power plants, are analysed on energy efficiency, energy consumption, renewable energy production, and greenhouse gas (GHG) emissions and compared with the performance of a 100% coal supply chain scenario, for a Dutch situation. The 60% biomass co-combustion supply chain scenarios show possibilities to reduce emissions up to 48%. The low co-combustion levels are effective to reduce GHG emissions, but the margins are small. Currently co-combustion of pellets is the norm. Co-combustion of combined torrefaction and pelleting (TOP) shows the best results, but is also the most speculative. The indicators from the renewable energy directive cannot be aligned. When biomass is regarded as scarce, co-combustion of small shares or no co-combustion is the best option from an energy perspective. When biomass is regarded as abundant, co-combustion of large shares is the best option from a GHG reduction perspective.

  8. Examinations of the process of hard coal and biomass blend combustion in OEA (oxygen enriched atmosphere)

    International Nuclear Information System (INIS)

    Pawlak-Kruczek, Halina; Ostrycharczyk, Michał; Czerep, Michał; Baranowski, Marcin; Zgóra, Jacek

    2015-01-01

    The benefits of oxygen enrichment have been demonstrated in a variety of industrial combustion applications, but to date no implementation of oxygen enrichment in boilers has been reported, primarily due to their already high thermal efficiencies and a very large scale of such systems, which require significant amounts of oxygen. But recently, oxygen combustion in boilers has become one of the CCS technologies which can be an effective tool for reducing greenhouse gases emissions, and oxygen enriched combustion is suitable for low-calorific fuels, including biomass. This paper analyses the use of oxygen enrichment in a furnace for co-firing of different kinds of biomass with hard coal in terms of emission and burnout impact (LOI). As a part of this research, the effect of injection oxygen mode and total oxygen concentration on the flue gas emission (SO_2, NO_x) and burnout from co-firing of straw and wooden biomass in different proportions (20% and 40%) with hard coal were studied. The co-firing tests were carried out in an isothermal flow reactor. One of the benefits from the OEA (oxygen enriched atmosphere) technology is more effective separation of CO_2 owing to the higher CO_2 concentration in the flue gas. The additional advantage of the OEA combustion technology in comparison with oxy-fuel combustion is that the OEA process needs lower O_2 purities and therefore it is cost-effective. Experimental tests on co-firing of 20% straw-hard coal blend were conducted in oxygen enriched (up to 25 and 30%) atmospheres with three variants of O_2 injection modes. NO_x, SO_2 emissions and burnout for the various atmospheres in the combustion chamber were studied. Moreover, co-firing tests were performed with 40% share of wooden biomass to examine the effect of the biomass share and a type on emission of NO_x and SO_2 in OEA. The two O_2 injection modes were investigated. In each case, the emission of SO_2 increases alongside an increase of oxygen concentration in

  9. Effect of organic calcium compounds on combustion characteristics of rice husk, sewage sludge, and bituminous coal: thermogravimetric investigation.

    Science.gov (United States)

    Zhang, Lihui; Duan, Feng; Huang, Yaji

    2015-04-01

    Experiments were conducted in a thermogravimetric analyzer to assess the enhancement of combustion characteristics of different solid fuels blended with organic calcium compounds (OCCs). Rice husk, sewage sludge, and bituminous coal, and two OCC were used in this study. Effect of different mole ratios of calcium to sulfur (Ca/S ratio) on the combustion characteristics were also investigated. Results indicated that combustion performance indexes for bituminous coal impregnated by OCC were improved, however, an inverse trend was found for sewage sludge because sewage sludge has lower ignition temperature and higher volatile matter content compared to those of OCC. For rice husk, effect of added OCC on the combustion characteristics is not obvious. Different solid fuels show different combustion characteristics with increases of Ca/S ratio. The maximum combustion performance indexes appear at Ca/S ratios of 1:1, 2:1, and 3:1 for OCC blended with Shenhua coal, rice husk, and sewage sludge, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Experimental analysis of a combustion reactor under co-firing coal with biomass

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Fabyo Luiz; Bazzo, Edson; Oliveira Junior, Amir Antonio Martins de [Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil). LabCET], e-mail: ebazzo@emc.ufsc.br; Bzuneck, Marcelo [Tractebel Energia S.A., Complexo Termeletrico Jorge Lacerda, Capivari de Baixo, SC (Brazil)], e-mail: marcelob@tractebelenergia.com.br

    2010-07-01

    Mitigation of greenhouse gases emission is one of the most important issues in energy engineering. Biomass is a potential renewable source but with limited use in large scale energy production because of the relative smaller availability as compared to fossil fuels, mainly to coal. Besides, the costs concerning transportation must be well analysed to determine its economic viability. An alternative for the use of biomass as a primary source of energy is the co-firing, that is the possibility of using two or more types of fuels combined in the combustion process. Biomass can be co-fired with coal in a fraction between 10 to 25% in mass basis (or 4 to 10% in heat-input basis) without seriously impacting the heat release characteristics of most boilers. Another advantage of cofiring, besides the significant reductions in fossil CO{sub 2} emissions, is the reduced emissions of NO{sub x} and SO{sub x}. As a result, co-firing is becoming attractive for power companies worldwide. This paper presents results of some experimental analysis on co-firing coal with rice straw in a combustion reactor. The influence of biomass thermal share in ash composition is also discussed, showing that alkali and earth alkaline compounds play the most important role on the fouling and slagging behavior when co-firing. Some fusibility correlations that can assist in the elucidation of these behavior are presented and discussed, and then applied to the present study. Results show that for a biomass thermal share up to 20%, significant changes are not expected in fouling and slagging behavior of ash. (author)

  11. Oxy-fuel combustion of millimeter-sized coal char: Particle temperatures and NO formation

    DEFF Research Database (Denmark)

    Brix, Jacob; Navascués, Leyre Gómez; Nielsen, Joachim Bachmann

    2013-01-01

    In this work, differences in particle temperature and NO yield during char oxidation in O2/N2 and O2/CO2 atmospheres, respectively, have been examined. A laboratory scale fixed bed reactor, operated isothermally at 1073 K, was used for combustion of millimeter-sized lignite and bituminous coal char...... increased with mass loading, by as much as 700 K above the furnace set point. The formation of NO from lignite char was not influenced by the change from N2 to CO2 whereas the NO yield from bituminous coal char was considerably lower in O2/CO2 compared O2/N2. For both chars the conversion to NO decreased...... as the O2 concentration or the particle size increased. However, for the bituminous coal char, a peak in NO yield was observed at an intermediate particle size of 0.1–0.2 g. The differences in the effect of gas atmosphere, O2 concentration, and particle mass on the NO yield from oxidation of bituminous...

  12. Direct recovery of boiler residue by combustion synthesis.

    Science.gov (United States)

    Nourbaghaee, Homan; Ghaderi Hamidi, Ahmad; Pourabdoli, Mahdi

    2018-04-01

    Boiler residue (BR) of thermal power plants is one of the important secondary sources for vanadium production. In this research, the aluminothermic self-propagating high-temperature synthesis (SHS) was used for recovering the transition metals of BR for the first time. The effects of extra aluminum as reducing agent and flux to aluminum ratio (CaO/Al) were studied and the efficiency of recovery and presence of impurities were measured. Aluminothermic reduction of vanadium and other metals was carried out successfully by SHS without any foreign heat source. Vanadium, iron, and nickel principally were reduced and gone into metallic master alloy as SHS product. High levels of efficiency (>80%) were achieved and the results showed that SHS has a great potential to be an industrial process for BR recovery. SHS produced two useful products. Metallic master alloy and fused glass slag that is applicable for ceramic industries. SHS can also neutralize the environmental threats of BR by a one step process. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Prediction method of unburnt carbon for coal fired utility boiler using image processing technique of combustion flame

    International Nuclear Information System (INIS)

    Shimoda, M.; Sugano, A.; Kimura, T.; Watanabe, Y.; Ishiyama, K.

    1990-01-01

    This paper reports on a method predicting unburnt carbon in a coal fired utility boiler developed using an image processing technique. The method consists of an image processing unit and a furnace model unit. temperature distribution of combustion flames can be obtained through the former unit. The later calculates dynamics of the carbon reduction from the burner stages to the furnace outlet using coal feed rate, air flow rate, chemical and ash content of coal. An experimental study shows that the prediction error of the unburnt carbon can be reduced to 10%

  14. 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.

  15. Application of dry separative methods for decreasing content the residues unburned coal and separation Fe from black coal flies ash

    Directory of Open Access Journals (Sweden)

    František Kaľavský

    2008-06-01

    Full Text Available Main obstacle using of fly ashes in building, that is its main consumer, is the residue of unburned coal; it is expressed of loss onignition - LOI. In present, the valid STN and EU standard limits the content of LOI to 3 – 5 %, in national conditions maximum 7 %.Application of processing technologies also has to assure utilization of fly ash that provides a possibility of complex utilizationof individual products obtained by modification.By means of corona separation, based on different conductivity of individual fly ash elements, it is possible to separate unburnedcoal particles. The fly ash sample from black coal burning in melting boiler that was deposited on fly ash deposit, content of LOIof dielectric particle 6,45 % at 61 % weight yield was achieved. In the samples taken from dry taking of fly ash the non-conductingproduct contained 7,72 % of LOI at 73 % of weight yield.

  16. Next-generation coal utilization technology development study. Environmentally-friendly coal combustion technology; O2/CO2 combustion technology; Sekitan riyo jisedai gijutsu kaihatsu chosa. Kankyo chowagata sekitan nensho gijutsu (sanso nensho gijutsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    For the purpose of developing combustion systems in which environmental pollutants are less emitted from coal-fired boilers, conducted in fiscal 1994 were a study of load followability of oxygen producing equipment, and element and basic tests on oxygen combustion systems. Dynamic simulations were made to confirm load followability of low-purity oxygen producing equipment. Further, a test was made on starting time of oxygen producing equipment. As a result of the simulation, favorable load followability was confirmed except for some of the process. The width of variation of the product oxygen purity was {plus_minus} 0.7% at maximum. In the element test on oxygen combustion systems, an experiment on the oxygen combustion using pulverized coal was conducted to study heat collection characteristics of furnace and response to multi-kind of coal. A study of balance of S content, experiments on characteristics of crushing/transporting pulverized coal, etc. were added. There were seen no peculiar differences in CO2 transport and air transport. 216 figs., 31 tabs.

  17. Roof instability characteristics and pre-grouting of the roof caving zone in residual coal mining

    Science.gov (United States)

    Zhao, Tong; Liu, Changyou

    2017-12-01

    Abandoned roadways and roof caving zones are commonly found in residual coal, and can destroy the integrity of the coal seam and roof. Resulting from mining-induced stress, continuous collapse and fracture instability in roof caving zones (RCZs) jeopardize the safety and efficiency of residual coal mining. Based on the engineering geology conditions of remining face 3101 in Shenghua Mine, the roof fracture and instability features of the RCZ were analyzed through physical simulation, theoretical analysis, and field measurements. In this case, influenced by the RCZ, the main roof across the RCZ fractured and rotated towards the goaf, greatly increasing the working resistance, and crushing the supports. The sudden instability of the coal pillars weakened its support of the main roof, thus resulting in long-key blocks across the RCZ and hinged roof structures, which significantly decreased the stability of the underlying immediate roof. This study establishes a mechanical model for the interactions between the surrounding rock and the supports in the RCZ, determines the reasonable working resistance, and examines the use of pre-grouting solidification restoration technology (PSRT) to solidify the RCZ and reinforce the coal pillars—thus increasing their bearing capacity. Field measurements revealed no roof flaking, inhomogeneous loading or support crushing, indicating that the PSRT effectively controlled the surrounding rock of the RCZ.

  18. The rates of production of CO and CO2 from the combustion of pulverized coal particles in a shock tube

    NARCIS (Netherlands)

    Commissaris, F.A.C.M.; Banine, V.Y.; Roekaerts, D.J.E.M.; Veefkind, A.

    1998-01-01

    This work presents some results of experiments on coal combustion in a shock tube, as well as a time-dependent model of the boundary layer of a single, burning char particle under similar conditions. The partial pressure of O2 in a shock tube was varied between 0 and 10 bar, with gas temperatures

  19. Utilization of stabilized municipal waste combustion ash residues as construction material

    International Nuclear Information System (INIS)

    Shieh, C.S.

    1992-01-01

    Stabilized municipal waste combustion (MWC) ash residues were investigated for their potential as construction material that can be beneficially used in terrestrial and marine environments. End-use products, such as patio stones, brick pavers, solid blocks, and reef units, were fabricated and tested for their engineering and chemical characteristics. engineering feasibility and environmental acceptability of using stabilized ash residues as construction material are discussed in this paper. Ash samples were collected from two mass-burn facilities and one refuse derived fuel (RDF) facility in Florida

  20. Experimental and Numerical Investigation of Effect of Coal Rank on Burn-off Time in Pulverized Coal Combustion

    OpenAIRE

    Nozawa, Sohei; Wada, Nozomi; Matsushita, Yosuke; Yamamoto, Tsuyoshi; Omori, Motohira; Harada, Tatsuro

    2012-01-01

    Thermogravimetry (TG) for two different coal ranks, Loy Yang coal and Newlands coal, was carried out in an atmospheric air environment. Detailed parameters of the heterogeneous oxidation reaction for each coal rank were estimated by analyzing the TG results. Heat and mass transfer of a single pulverized coal particle that was heated at a constant temperature were numerically simulated. In this calculation, the decrease in the mass ratio caused by the oxidation reaction was considered. The num...

  1. Application of activated carbons from coal and coconut shell for removing free residual chlorine.

    Science.gov (United States)

    Ogata, Fumihiko; Tominaga, Hisato; Ueda, Ayaka; Tanaka, Yuko; Iwata, Yuka; Kawasaki, Naohito

    2013-01-01

    This study investigated the removal of free residual chlorine by activated carbon (AC). ACs were prepared from coal (AC1) and coconut shell (AC2). The specific surface area of AC1 was larger than that of AC2. The removal of free residual chlorine increased with elapsed time and amount of adsorbent. The removal mechanism of free residual chlorine was the dechlorination reaction between hypochlorous acid or hypochlorite ion and AC. Moreover, AC1 was useful in the removal of free residual chlorine in tap water. The optimum condition for the removal of free residual chlorine using a column is space velocity 306 1/h; liner velocity 6.1 m/h.

  2. Recovery of plutonium from the combustion residues of alpha-bearing solid wastes

    International Nuclear Information System (INIS)

    Gompper, K.; Wieczorek, H.

    1991-01-01

    Experimental researches on plutonium dioxide dissolution in nitric acid in inactive and alpha-bearing wastes are presented in this report. After a review of the literature published on dissolution methods of PuO 2 combustion residues. Then results obtained in the ALONA plant on the dissolution of plutonium containing ashes in sulfuric acid and nitric acid are presented. Plutonium purification is studied. At last a simplified scheme of processing based on results obtained

  3. Beneficial Use and Recycling of Municipal Waste Combustion Residues - A Comprehensive Resource Document

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, C.; Shepherd, P.

    1999-04-26

    This document summarizes information from worldwide sources on the beneficial use of residues from the combustion of municipal. The information presented, including results of numerous research projects, field demonstrations, and actual full-scale projects, demonstrates that the ash can be safely used. It includes data on ash characteristics, environmental considerations, guidance on selected ash use applications, and information on federal and state regulations and policies affecting ash use.

  4. Energy and emission aspects of co-combustion solid recovered fuel with coal in a stoker boiler

    Science.gov (United States)

    Wasielewski, Ryszard; Głód, Krzysztof; Telenga-Kopyczyńska, Jolanta

    2018-01-01

    The results of industrial research on co-combustion of solid recovered fuel (SRF) with hard coal in a stoker boiler type WR-25 has been presented. The share of SRF in the fuel mixture was 10%. During the co-combustion of SRF, no technological disturbances or significant reduction in energy efficiency of the boiler were noted. Obtained SO2, NOx and CO emissions were comparable with coal combustion but dust emissions increased. During combustion of the coal mixture with a 10% share of SRF in the test boiler WR-25, the emission standards established for the combustion of the dedicated fuel were met. However, comparison of obtained emission results with the emission standards established for co-incineration of waste, revealed the exceedance of permissible levels of HCl, dust, heavy metals, dioxins and furans. Additionally, the residence time of flue gases in over 850°C conditions for the test boiler WR-25 was too short (1.3 seconds) in refer to the legislative requirements (2 seconds) for the thermal conversion of waste.

  5. Energy and emission aspects of co-combustion solid recovered fuel with coal in a stoker boiler

    Directory of Open Access Journals (Sweden)

    Wasielewski Ryszard

    2018-01-01

    Full Text Available The results of industrial research on co-combustion of solid recovered fuel (SRF with hard coal in a stoker boiler type WR-25 has been presented. The share of SRF in the fuel mixture was 10%. During the co-combustion of SRF, no technological disturbances or significant reduction in energy efficiency of the boiler were noted. Obtained SO2, NOx and CO emissions were comparable with coal combustion but dust emissions increased. During combustion of the coal mixture with a 10% share of SRF in the test boiler WR-25, the emission standards established for the combustion of the dedicated fuel were met. However, comparison of obtained emission results with the emission standards established for co-incineration of waste, revealed the exceedance of permissible levels of HCl, dust, heavy metals, dioxins and furans. Additionally, the residence time of flue gases in over 850°C conditions for the test boiler WR-25 was too short (1.3 seconds in refer to the legislative requirements (2 seconds for the thermal conversion of waste.

  6. The effect of char structure on burnout during pulverized coal combustion at pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G.; Wu, H.; Benfell, K.E.; Lucas, J.A.; Wall, T.F.

    1999-07-01

    An Australian bituminous coal sample was burnt in a drop tube furnace (DTF) at 1 atm and a pressurized drop tube furnace (PDTF) at 15 atm. The char samples were collected at different burnout levels, and a scanning electron microscope was used to examine the structures of chars. A model was developed to predict the burnout of char particles with different structures. The model accounts for combustion of the thin-walled structure of cenospheric char and its fragmentation during burnout. The effect of pressure on reaction rate was also considered in the model. As a result, approximately 40% and 70% cenospheric char particles were observed in the char samples collected after coal pyrolysis in the DTF and PDTF respectively. A large number of fine particles (< 30 mm) were observed in the 1 atm char samples at burnout levels between 30% and 50%, which suggests that significant fragmentation occurred during early combustion. Ash particle size distributions show that a large number of small ash particles formed during burnout at high pressure. The time needed for 70% char burnout at 15 atm is approximately 1.6 times that at 1 atm under the same temperature and gas environment conditions, which is attributed to the different pressures as well as char structures. The overall reaction rate for cenospheric char was predicted to be approximately 2 times that of the dense chars, which is consistent with previous experimental results. The predicted char burnout including char structures agrees reasonably well with the experimental measurements that were obtained at 1 atm and 15 atm pressures.

  7. Environmental, physical and structural characterisation of geopolymer matrixes synthesised from coal (co-)combustion fly ashes

    International Nuclear Information System (INIS)

    Alvarez-Ayuso, E.; Querol, X.; Plana, F.; Alastuey, A.; Moreno, N.; Izquierdo, M.; Font, O.; Moreno, T.; Diez, S.; Vazquez, E.; Barra, M.

    2008-01-01

    The synthesis of geopolymer matrixes from coal (co-)combustion fly ashes as the sole source of silica and alumina has been studied in order to assess both their capacity to immobilise the potentially toxic elements contained in these coal (co-)combustion by-products and their suitability to be used as cement replacements. The geopolymerisation process has been performed using (5, 8 and 12 M) NaOH solutions as activation media and different curing time (6-48 h) and temperature (40-80 o C) conditions. Synthesised geopolymers have been characterised with regard to their leaching behaviour, following the DIN 38414-S4 [DIN 38414-S4, Determination of leachability by water (S4), group S: sludge and sediments. German standard methods for the examination of water, waste water and sludge. Institut fuer Normung, Berlin, 1984] and NEN 7375 [NEN 7375, Leaching characteristics of moulded or monolithic building and waste materials. Determination of leaching of inorganic components with the diffusion test. Netherlands Normalisation Institute, Delft, 2004] procedures, and to their structural stability by means of compressive strength measurements. In addition, geopolymer mineralogy, morphology and structure have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. It was found that synthesised geopolymer matrixes were only effective in the chemical immobilisation of a number of elements of environmental concern contained in fly ashes, reducing (especially for Ba), or maintaining their leachable contents after the geopolymerisation process, but not for those elements present as oxyanions. Physical entrapment does not seem either to contribute in an important way, in general, to the immobilisation of oxyanions. The structural stability of synthesised geopolymers was mainly dependent on the glass content of fly ashes, attaining at the optimal activation conditions (12 M NaOH, 48 h, 80 o C

  8. Regenerable sorbents for mercury capture in simulated coal combustion flue gas.

    Science.gov (United States)

    Rodríguez-Pérez, Jorge; López-Antón, M Antonia; Díaz-Somoano, Mercedes; García, Roberto; Martínez-Tarazona, M Rosa

    2013-09-15

    This work demonstrates that regenerable sorbents containing nano-particles of gold dispersed on an activated carbon are efficient and long-life materials for capturing mercury species from coal combustion flue gases. These sorbents can be used in such a way that the high investment entailed in their preparation will be compensated for by the recovery of all valuable materials. The characteristics of the support and dispersion of gold in the carbon surface influence the efficiency and lifetime of the sorbents. The main factor that determines the retention of mercury and the regeneration of the sorbent is the presence of reactive gases that enhance mercury retention capacity. The capture of mercury is a consequence of two mechanisms: (i) the retention of elemental mercury by amalgamation with gold and (ii) the retention of oxidized mercury on the activated carbon support. These sorbents were specifically designed for retaining the mercury remaining in gas phase after the desulfurization units in coal power plants. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Bioextraction of copper and zinc from fly ash from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wilczok, T; Cwalina, B; Chrostowska, D

    1986-02-01

    Results are evaluated of investigations carried out by the Institute of Chemistry and Physics of the Silesia Medical Academy in Sosnowiec into feasibility of bacterial leaching for utilization of fly ash from combustion of black coal. Fly ash separated by electrostatic precipitators in the Dolna Odra power plant fired with black coal was used. Copper content in the fly ash on the average was 0.012%, that of zinc was 0.025%. When Thiobacillus ferroxidans, Thiobacillus thiooxidans and bacteria separated from fly ash were used leaching efficiency after 21 days ranged from 69 to 87% in the case of copper and from 48 to 72% in the case of zinc. Origin of bacteria separated from fly ash was unclear. Autochthonous bacteria in the fly ash being leached increased efficiency of bacterial leaching. Effects of autochthonous bacteria were similar to those of the bacterial culture of Thiobacillus ferroxidans and Thiobacillus thiooxidans. Investigation results were shown in a table and 2 diagrams. 19 references.

  10. Atmospheric fluidized-bed combustion (AFBC) co-firing of coal and hospital waste

    International Nuclear Information System (INIS)

    1993-02-01

    The proposed project involves co-firing of coal and medical waste (including infectious medical waste) in an atmospheric fluidized-bed combustor (AFBC) to safely dispose of medical waste and produce steam for hospital needs. Combustion at the design temperature and residence time (duration) in the AFBC has been proven to render infectious medical waste free of disease producing organisms. The project would be located at the Veterans Affairs (VA) Medical Center in Lebanon, Pennsylvania. The estimated cost of the proposed AFBC facility is nearly $4 million. It would be jointly funded by DOE, Veterans Affairs, and Donlee Technologies, Inc., of York, Pennsylvania, under a cooperative agreement between DOE and Donlee. Under the terms of this agreement, $3.708 million in cost-shared financial assistance would be jointly provided by DOE and the Veterans Affairs (50/50), with $278,000 provided by Donlee. The purposes of the proposed project are to: (1) provide the VA Medical Center and the Good Samaritan Hospital (GSH), also of Lebanon, Pennsylvania, with a solution for disposal of their medical waste; and (2) demonstrate that a new coal-burning technology can safely incinerate infectious medical waste, produce steam to meet hospital needs, and comply with environmental regulations

  11. Removal of unburned carbon in fly ash produced in coal combustion process

    International Nuclear Information System (INIS)

    Velasquez V, Leonardo F; De La Cruz M, Javier F; Sanchez M, Jhon F

    2007-01-01

    The coal unburned in flying ashes obtained in the processes of coal combustion is the main disadvantage for its use in the industry of the construction. This material normally has a size of particle greater than the mineral material, therefore it is possible to be separated in a considerable percentage, obtaining double benefit: the reusability of unburned like fuel or precursor for the activated charcoal production and the use of the mineral material in the industry of the construction since the organic matter has retired him that disables its use. In this work it is experienced with a sifted technique of separation by for three obtained flying ash samples with different technology (travelling Grill, pneumatic injection and overturning grill), were made grain sized analyses with meshes of a diameter of particle greater to 0,589 mm, the short analyses were made to them next to the retained material in each mesh and the unburned percentage of removal was determined of. The technique was compared with other developing.

  12. Combustion of pulverized coal in vortex structures. Final report, October 1, 1993--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Gollahalli, S.R.; Butuk, N.

    1996-03-01

    The objectives of the project were: (i) to understand the effects of heating one of the streams on the characteristics of shear layers, (ii) to investigate the changes in the characteristics of large scale vortex structures in the shear layer caused by the introduction of inert solid particles in one of the feed streams; (iii) to understand the effects of pyrolyzing solids on the shear layer behavior; and (iv) to study the effects of combustion of particles and their pyrolysis products on the shear layer structure, heat release rate, and pollutant emission characteristics. An experimental facility for generating two-dimensional shear layers containing vortex structures has been designed and fabricated. The experimental facility is essentially a low speed wind tunnel designed to (i) provide two gas streams, initially with uniform velocity profiles and isotropic turbulence, mixing at the end of a splitter plate, (ii) introduce vorticity by passively perturbing one of the streams, (iii) allow heating of one of the streams to temperatures high enough to cause pyrolysis of coal particles, and (iv) provide a natural gas flame in one of the streams to result in ignition and burning of coal particles.

  13. SO2 emission reducing by Ca(OH)2 using at combustion of coal from East-Maritsa basin

    International Nuclear Information System (INIS)

    Batov, S.; Gadzhanov, P.; Popov, D.; Panchev, T.; Mikhajlov, Ya.; Shushulov, D.; Grozev, A.

    1997-01-01

    The 'Maritsa-Iztok' coal field contains about 65% of the lignite and 57% of the Bulgarian coal resources.The 'Maritsa-Iztok' lignite coal have a low combustion temperature and high concentration of ashes, moisture and sulfur. The concentration of sulphur oxides emitted is about 800 000 t per year, which is among the highest concentrations for Europe. In order to reduce the sulphur concentration, theoretical and experimental studies have been performed. A determination of the efficiency of some new methods for SO 2 reduction has been done. In this paper the results from experiments using Ca(OH) 2 as reagent, are presented. The experimental facility is a non-cooled combustion chamber which provides the same conditions as in the lignite coal boilers. In the experiments ground and dried lignite coal have been used. The controlled values are O 2 , CO, NO x , SO 2 , as well as the temperature of the hot and cold air and the combustion products after the cooler and absorber. Four different technologies have been performed. The first is adding of Ca(OH) 2 which give about 30% maximal SO 2 reducing for grain size 45μm and Ca/S=1.6. The obtaining of this small size is now difficult. The second technology is introduction of Ca(OH) 2 in the combustion chamber at a temperature 900-1050 o C. The cleaning efficiency is about 48.5% for the optimal concentration of the additive. As a washing of the combustion product with water in the absorber after the desulfurization. The second phase give 20% additional cleaning. Thus the total cleaning effect is 65-70%. The third method used lime washing of the combustion products. For the Bulgarian coal with a great S content it is the most suitable method. It gives a SO 2 cleaning up to 95%. Lime wash with pH=12.3 has been used with various amounts of the reagent. Experiments with different amounts of lime wash and different quality of the coal are performed and the specific reagent consumption has been determined

  14. Integrating multi-objective optimization with computational fluid dynamics to optimize boiler combustion process of a coal fired power plant

    International Nuclear Information System (INIS)

    Liu, Xingrang; Bansal, R.C.

    2014-01-01

    Highlights: • A coal fired power plant boiler combustion process model based on real data. • We propose multi-objective optimization with CFD to optimize boiler combustion. • The proposed method uses software CORBA C++ and ANSYS Fluent 14.5 with AI. • It optimizes heat flux transfers and maintains temperature to avoid ash melt. - Abstract: The dominant role of electricity generation and environment consideration have placed strong requirements on coal fired power plants, requiring them to improve boiler combustion efficiency and decrease carbon emission. Although neural network based optimization strategies are often applied to improve the coal fired power plant boiler efficiency, they are limited by some combustion related problems such as slagging. Slagging can seriously influence heat transfer rate and decrease the boiler efficiency. In addition, it is difficult to measure slag build-up. The lack of measurement for slagging can restrict conventional neural network based coal fired boiler optimization, because no data can be used to train the neural network. This paper proposes a novel method of integrating non-dominated sorting genetic algorithm (NSGA II) based multi-objective optimization with computational fluid dynamics (CFD) to decrease or even avoid slagging inside a coal fired boiler furnace and improve boiler combustion efficiency. Compared with conventional neural network based boiler optimization methods, the method developed in the work can control and optimize the fields of flue gas properties such as temperature field inside a boiler by adjusting the temperature and velocity of primary and secondary air in coal fired power plant boiler control systems. The temperature in the vicinity of water wall tubes of a boiler can be maintained within the ash melting temperature limit. The incoming ash particles cannot melt and bond to surface of heat transfer equipment of a boiler. So the trend of slagging inside furnace is controlled. Furthermore, the

  15. Fluidized bed combustion of single coal char particles at high CO{sub 2} concentration

    Energy Technology Data Exchange (ETDEWEB)

    Scala, F.; Chirone, R. [CNR, Naples (Italy)

    2010-12-15

    Combustion of single coal char particles was studied at 850{sup o}C in a lab-scale fluidized bed at high CO{sub 2} concentration, typical of oxyfiring conditions. The burning rate of the particles was followed as a function of time by continuously measuring the outlet CO and O{sub 2} concentrations. Some preliminary evaluations on the significance of homogeneous CO oxidation in the reactor and of carbon gasification by CO{sub 2} in the char were also carried out. Results showed that the carbon burning rate increases with oxygen concentration and char particle size. The particle temperature is approximately equal to that of the bed up to an oxygen concentration of 2%, but it is considerably higher for larger oxygen concentrations. Both CO{sub 2} gasification of char and homogeneous CO oxidation are not negligible. The gasification reaction rate is slow and it is likely to be controlled by intrinsic kinetics. During purely gasification conditions the extent of carbon loss due to particle attrition by abrasion (estimated from the carbon mass balance) appears to be much more important than under combustion conditions.

  16. Multifunctional (NOx/CO/O2) Solid-State Sensors For Coal Combustion Control

    Energy Technology Data Exchange (ETDEWEB)

    Eric D. Wachsman

    2006-12-31

    Solid-state sensors were developed for coal combustion control and the understanding of sensing mechanisms was advanced. Several semiconducting metal oxides (p-type and n-type) were used to fabricate sensor electrodes. The adsorption/desorption characteristics and catalytic activities of these materials were measured with Temperature Programmed Desorption (TPD) and Temperature Programmed Reaction (TPR) experiments. The sensitivity, selectivity, and response time of these sensors were measured for steps of NO, NO{sub 2}, CO, CO{sub 2}, O{sub 2}, and H{sub 2}O vapor in simple N{sub 2}-balanced and multi-component, simulated combustion-exhaust streams. The role of electrode microstructure and fabrication parameters on sensing performance was investigated. Proof for the proposed sensing mechanism, Differential Electrode Equilibria, was demonstrated by relating the sensing behavior (sensitivities and cross-sensitivities) of the various electrode materials to their gas adsorption/desorption behaviors and catalytic activities. A multifunctional sensor array consisting of three sensing electrodes and an integrated heater and temperature sensors was fabricated with tape-casting and screen-printing and its NO{sub x} sensing performance was measured. The multifunctional sensor demonstrated it was possible to measure NO{sub 2} independent of NO by locally heating one of the sensing electrodes. The sensor technology was licensed to Fuel FX International, Inc. Fuel FX has obtained investor funding and is developing prototype sensors as a first step in their commercialization strategy for this technology.

  17. Fly ashes from coal and petroleum coke combustion: current and innovative potential applications.

    Science.gov (United States)

    González, Aixa; Navia, Rodrigo; Moreno, Natalia

    2009-12-01

    Coal fly ashes (CFA) are generated in large amounts worldwide. Current combustion technologies allow the burning of fuels with high sulfur content such as petroleum coke, generating non-CFA, such as petroleum coke fly ash (PCFA), mainly from fluidized bed combustion processes. The disposal of CFA and PCFA fly ashes can have severe impacts in the environment such as a potential groundwater contamination by the leaching of heavy metals and/or particulate matter emissions; making it necessary to treat or reuse them. At present CFA are utilized in several applications fields such as cement and concrete production, agriculture and soil stabilization. However, their reuse is restricted by the quality parameters of the end-product or requirements defined by the production process. Therefore, secondary material markets can use a limited amount of CFA, which implies the necessity of new markets for the unused CFA. Some potential future utilization options reviewed herein are zeolite synthesis and valuable metals extraction. In comparison to CFA, PCFA are characterized by a high Ca content, suggesting a possible use as neutralizers of acid wastewaters from mining operations, opening a new potential application area for PCFA that could solve contamination problems in emergent and mining countries such as Chile. However, this potential application may be limited by PCFA heavy metals leaching, mainly V and Ni, which are present in PCFA in high concentrations.

  18. Wood pellets in a power plant - mixed combustion of coal and wood pellets

    International Nuclear Information System (INIS)

    Nupponen, M.

    2001-01-01

    The author reviews in his presentation the development of Turku Energia, the organization of the company, the key figures of the company in 2000, as well as the purchase of energy in 2000. He also presents the purchase of basic heat load, the energy production plants of the company, the sales of heat in 2000, the emissions of the plants, and the fuel consumption of the plants in 2000. The operating experiences of the plants are also presented. The experiences gained in Turku Energia on mixed combustion of coal and wood pellets show that the mixing ratios, used at the plants, have no effect on the burning properties of the boiler, and the use of wood pellets with coal reduce the SO 2 and NO x emissions slightly. Simultaneously the CO 2 share of the wood pellets is removed from the emissions calculations. Several positive effects were observed, including the disappearance of the coal smell of the bunker, positive publicity of the utilization of wood pellets, and the subsidies for utilization of indigenous fuels in power generation. The problems seen include the tendency of wood pellets to arc the silos, especially when the pellets include high quantities of dust, and the loading of the trucks and the pneumatic unloading of the trucks break the pellets. Additionally the wood pellets bounce on the conveyor so they drop easily from the conveyor, the screw conveyors designed for conveying grain are too weak and they get stuck easily, and static electricity is easily generated in the plastic pipe used as the discharge pipe for wood pellet (sparkling tendency). This disadvantage has been overcome by using metal net and grounding

  19. Removal of mercury from coal-combustion flue gas using regenerable sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, C S; Albiston, J; Broderick, T E; Stewart, R M

    1999-07-01

    The US EPA estimates that coal-fired power plants constitute the largest anthropogenic source of mercury emissions in the US. The Agency has contemplated emission regulations for power plants, but the large gas-flow rates and low mercury concentrations involved have made current treatment options prohibitively expensive. ADA Technologies, Inc. (Englewood, Colorado), in conjunction with the US DOE, is developing regenerable sorbents for the removal and recovery of mercury from flue gas. These sorbents are based on the ability of noble metals to amalgamate mercury at typical flue-gas temperatures and release mercury at higher temperatures. The process allows for recovery of mercury with minimal volumes of secondary wastes and no impact on fly ash quality. In 1997 and 1998, ADA tested a 20-cfm sorbent unit at CONSOL Inc.'s coal-combustion test facility in Library, PA. Results from the 1997 tests indicated that the sorbent can remove elemental and oxidized mercury and can be regenerated without loss of capacity. Design changes were implemented in 1998 to enhance the thermal efficiency of the process and to recover the mercury in a stable form. Testing during autumn, 1998 demonstrated 60% to 90% removal efficiency of mercury from a variety of different coals. However, contradictory removal results were obtained at the end of the test period. Subsequent laboratory analyses indicated that the sorbent had lost over half its capacity for mercury due to a decrease in available sites for mercury sorption. The presence of sulfur compounds on the sorbent suggests that thermal cycling may have condensed acid gases on the sorbent leading to deterioration of the active sorption sites. The regeneration time/temperature profile has been altered to minimize this potential in the upcoming power plant tests.

  20. Disposal of residue from sifting of combustible waste; Avsaettning av siktrest fraan foerbehandling av braennbart avfall

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik

    2012-11-01

    In waste to energy plants, unwanted species in the fuel may cause corrosion, deposits, agglomeration in the fuel bed, and emissions of pollutants. Countermeasures to such problems are often costly. For at least some of the waste, the fuel properties can be improved by introducing a pretreatment system in which the fine fraction is separated from the waste by sifting. This method has been studied in an earlier Waste Refinery project, WR-06. That study pointed at advantages in performance of the boiler plant and a rough economical analysis indicated substantial benefits. The drawback of the pretreatment was that the residue (the fine fraction) showed as high content of total organic carbon (TOC) as 37 %, by weight. Such a waste fraction is not allowed to be landfilled in Sweden. High TOC content is also a limiting factor for usage as a secondary construction material. To become an applicable pretreatment method, it is necessary to find an appropriate disposal method for the residue material. Present work investigates different possibilities to handle the sifting residue, assuming it has the same properties as in previous study. The residue from sifting needs further treatment, preferably with energy recovery. There are some alternatives, such as combustion, gasification, anaerobic or aerobic digestion. To reduce problems associated by combustion, the waste may be burnt in another more suitable furnace. An alternative is gasification, but that treatment method is not yet an established process for waste fuels. Another option is treatment by anaerobic or aerobic digestion. The high concentrations of metals, however, limit the use of the biologically treated waste to landfilling sites, where it may be utilized as a construction material. The high metal concentrations in the sifting residue imply that it must be kept separate from other biodegradable wastes which are used to produce fertilizers. Thus, this treatment alternative will likely require substantial new

  1. Chemical characterization of bottom ashes generated during combustion of a Colombian mineral coal in a thermal power plant; Caracterizacao quimica das cinzas de fundo originadas pela combustao, em usina termoeletrica, de um carvao mineral do nordeste da Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, H.S.; Nogueira, R.E.F.Q.; Lobo, C.J.S.; Nobre, A.I.S.; Sales, J.C.; Silva, C.J.M., E-mail: hspfisica@hotmail.com [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Centro de Tecnologia. Dept. de Engenharia Metalurgica e de Materiais

    2012-07-01

    Bottom ashes generated during combustion of a mineral coal from Colombia were characterized by X-ray fluorescence spectrometry and X-ray diffraction. The interest in this particular coal is due to the fact that it will be used by a thermal power plant in Ceara, Northeastern Brazil, where it could produce over 900 tons of different residues/combustion products every day. Results from Xray fluorescence allowed identification and quantification of elements present in the sample: silicon (59,17%), aluminum (13,17%), iron (10,74%), potassium (6,11%), titanium (2,91%), calcium (4,97%), sulphur (0,84%) and others (2,09%). The X-ray diffraction revealed patterns from silica, mullite, calcium sulphate and hydrated sodium. Results obtained so far indicate that the material is a potential raw-material for use in the formulation of ceramic components (author)

  2. Combustion of Coal-Mule Briquettes / Spalanie Brykietów Z Mułu Węglowego

    Science.gov (United States)

    Kijo-Kleczkowska, Agnieszka

    2013-09-01

    Combustion technologies coal-mule fuels create a number of new possibilities for organising combustion processes so that they fulfil contemporary requirements (e.g., in terms of the environment protection- related issues). The paper describes the problems of coal-mule fuel combustion that have acquired a wider significance as the quality requirements of coal combustion in power plants have been growing. Coal mines that want to fulfill expectations of power industry workers have been forced to develop and modernize plants of coal wet cleaning. It all results in the growing amount of waste arising in the process of coal wet cleaning which contains smaller and smaller coal undersizes. In this situation the concept of direct combustion of the above mentioned waste and their co-combustion with other fuels, coal and biomass, seems to be attractive. Biomass is one from the most promising sources of renewable energy. The main aim of the paper is to identify the mechanism and kinetics of combustion of coal-mule fuels and their co- -combustion with coal and biomass in the briquettes form based on extensive experimental research in air. Niekorzystny bilans paliwowy naszego kraju powoduje nadmierne obciążenie środowiska, wywołane emisją CO2, NOx, SO2 i pyłów, a także powiększeniem powierzchni koniecznych na składowanie wciąż narastających stałych odpadów paleniskowych. Górnictwo, od którego energetyka oczekuje coraz lepszego paliwa, musi stosować głębsze wzbogacanie węgla. Powoduje to ciągłą produkcję odpadów w postaci mułów poflotacyjnych. Najlepszą metodą utylizacji tych mułów jest ich spalanie w postaci zawiesin, a także ich współspalanie z innymi paliwami, węglem czy biomasą. Biomasa jest bowiem jednym z najbardziej obiecujących źródeł OZE, a jej współspalanie z paliwami węglowymi znajduje w ostatnich latach coraz szersze zastosowanie zarówno w kraju, jak i na świecie. W tej sytuacji istotne jest prowadzenie badań naukowych

  3. Differential pulmonary inflammation and in vitro cytotoxicity of size-fractionated fly ash particles from pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    M. Ian Gilmour; Silvia O' Connor; Colin A.J. Dick; C. Andrew Miller; William P. Linak [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States). National Health and Environmental Effects Research Laboratory

    2004-03-01

    Exposure to airborne particulate matter (PM) has been associated with adverse health effects in humans. Pulmonary inflammatory responses were examined in CD1 mice after intratracheal instillation of 25 or 100 {mu}g of ultrafine ({lt}0.2 {mu}m), fine ({lt}2.5 {mu}m), and coarse ({gt}2.5 {mu}m) coal fly ash from a combusted Montana subbituminous coal, and of fine and coarse fractions from a combusted western Kentucky bituminous coal. After 18 hr, the lungs were lavaged and the bronchoalveolar fluid was assessed for cellular influx, biochemical markers, and pro-inflammatory cytokines. The responses were compared with saline and endotoxin as negative and positive controls, respectively. On an equal mass basis, the ultrafine particles from combusted Montana coal induced a higher degree of neutrophil inflammation and cytokine levels than did the fine or coarse PM. The western Kentucky fine PM caused a moderate degree of inflammation and protein levels in bronchoalveolar fluid that were higher than the Montana fine PM. Coarse PM did not produce any significant effects. In vitro experiments with rat alveolar macrophages showed that of the particles tested, only the Montana ultrafine displayed significant cytotoxicity. It is concluded that fly ash toxicity is inversely related with particle size and is associated with increased sulfur and trace element content. 42 refs., 5 figs., 3 tabs.

  4. The synergistic effect in coal/biomass blend briquettes combustion on elements behavior in bottom ash using ICP-OES

    Energy Technology Data Exchange (ETDEWEB)

    Lazaroiu, G.; Frentiu, T.; Maescu, L.; Mihaltan, A.; Ponta, M.; Frentiu, M.; Cordos, E. [Universitatea Politehnica din Bucuresti, Bucharest (Romania)

    2009-05-15

    This paper focuses on the study of the synergistic effect in coal/biomass blend briquettes combustion on behavior of Al, As, Ba, Cd, Co. Cr, Cu, Fe, Ga, K, Mn, Mo, Ni, P, Pb, Si, V, W, Zn, Zr and characterization of raw materials and bottom ashes. The manufacturing of coal/biomass briquettes although not commonly used is an attractive approach, as briquettes combustion is more technologically advantageous than the fluidized bed combustion. In the same time this technology is a way to render valuable materials of low calorific power and results in diminishing polluting emission. Raw materials and briquettes from different blends of pitcoal/sawdust were subjected to combustion in a 55 kW-boiler. The total content of elements after digestion in the HNO{sub 3} - HF mixture and the content in water leachate at a solid/liquid ratio of 1:2 were determined both in raw materials and bottom ash by ICP-OES. The total content of elements was higher in pitcoal than in sawdust. The synergistic effect depends both on coal/biomass ratio in blend and element nature. The water leachable fraction of elements from ash decreased along with the increase of sawdust weight excepting macronutrients (K, P) and Si.

  5. Dry sorbent injection of trona to control acid gases from a pilot-scale coal-fired combustion facility

    Directory of Open Access Journals (Sweden)

    Tiffany L. B. Yelverton

    2016-01-01

    Full Text Available  Gaseous and particulate emissions from the combustion of coal have been associated with adverse effects on human and environmental health, and have for that reason been subject to regulation by federal and state governments. Recent regulations by the United States Environmental Protection Agency have further restricted the emissions of acid gases from electricity generating facilities and other industrial facilities, and upcoming deadlines are forcing industry to consider both pre- and post-combustion controls to maintain compliance. As a result of these recent regulations, dry sorbent injection of trona to remove acid gas emissions (e.g. HCl, SO2, and NOx from coal combustion, specifically 90% removal of HCl, was the focus of the current investigation. Along with the measurement of HCl, SO2, and NOx, measurements of particulate matter (PM, elemental (EC, and organic carbon (OC were also accomplished on a pilot-scale coal-fired combustion facility. Gaseous and particulate emissions from a coal-fired combustor burning bituminous coal and using dry sorbent injection were the focus of the current study. From this investigation it was shown that high levels of trona were needed to achieve the goal of 90% HCl removal, but with this increased level of trona injection the ESP and BH were still able to achieve greater than 95% fine PM control. In addition to emissions reported, measurement of acid gases by standard EPA methods were compared to those of an infrared multi-component gas analyzer. This comparison revealed good correlation for emissions of HCl and SO2, but poor correlation in the measurement of NOx emissions.

  6. Modeling and Simulation on NOx and N2O Formation in Co-combustion of Low-rank Coal and Palm Kernel Shell

    Directory of Open Access Journals (Sweden)

    Mahidin Mahidin

    2012-12-01

    Full Text Available NOx and N2O emissions from coal combustion are claimed as the major contributors for the acid rain, photochemical smog, green house and ozone depletion problems. Based on the facts, study on those emissions formation is interest topic in the combustion area. In this paper, theoretical study by modeling and simulation on NOx and N2O formation in co-combustion of low-rank coal and palm kernel shell has been done. Combustion model was developed by using the principle of chemical-reaction equilibrium. Simulation on the model in order to evaluate the composition of the flue gas was performed by minimization the Gibbs free energy. The results showed that by introduced of biomass in coal combustion can reduce the NOx concentration in considerably level. Maximum NO level in co-combustion of low-rank coal and palm kernel shell with fuel composition 1:1 is 2,350 ppm, low enough compared to single low-rank coal combustion up to 3,150 ppm. Moreover, N2O is less than 0.25 ppm in all cases. Keywords: low-rank coal, N2O emission, NOx emission, palm kernel shell

  7. Thermogravimetric study of the combustion of Tetraselmis suecica microalgae and its blend with a Victorian brown coal in O2/N2 and O2/CO2 atmospheres.

    Science.gov (United States)

    Tahmasebi, Arash; Kassim, Mohd Asyraf; Yu, Jianglong; Bhattacharya, Sankar

    2013-12-01

    The combustion characteristics of microalgae, brown coal and their blends under O2/N2 and O2/CO2 atmospheres were studied using thermogravimetry. In microalgae combustion, two peaks at 265 and 485°C were attributable to combustion of protein and carbohydrate with lipid, respectively. The DTG profile of coal showed one peak with maximum mass loss rate at 360°C. Replacement of N2 by CO2 delayed the combustion of coal and microalgae. The increase in O2 concentration did not show any effect on combustion of protein at the first stage of microalgae combustion. However, between 400 and 600°C, with the increase of O2 partial pressure the mass loss rate of microalgae increased and TG and DTG curves of brown coal combustion shifted to lower temperature zone. The lowest and highest activation energy values were obtained for coal and microalgae, respectively. With increased microalgae/coal ratio in the blends, the activation energy increased due to synergy effect. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Trends of multiple air pollutants emissions from residential coal combustion in Beijing and its implication on improving air quality for control measures

    Science.gov (United States)

    Xue, Yifeng; Zhou, Zhen; Nie, Teng; Wang, Kun; Nie, Lei; Pan, Tao; Wu, Xiaoqing; Tian, Hezhong; Zhong, Lianhong; Li, Jing; Liu, Huanjia; Liu, Shuhan; Shao, Panyang

    2016-10-01

    Residential coal combustion is considered to be an important source of air pollution in Beijing. However, knowledge regarding the emission characteristics of residential coal combustion and the related impacts on the air quality is very limited. In this study, we have developed an emission inventory for multiple hazardous air pollutants (HAPs) associated with residential coal combustion in Beijing for the period of 2000-2012. Furthermore, a widely used regional air quality model, the Community Multi-Scale Air Quality model (CMAQ), is applied to analyze the impact of residential coal combustion on the air quality in Beijing in 2012. The results show that the emissions of primary air pollutants from residential coal combustion have basically remained the same levels during the past decade, however, along with the strict emission control imposed on major industrial sources, the contribution of residential coal combustion emissions to the overall emissions from anthropogenic sources have increased obviously. In particular, the contributions of residential coal combustion to the total air pollutants concentrations of PM10, SO2, NOX, and CO represent approximately 11.6%, 27.5%, 2.8% and 7.3%, respectively, during the winter heating season. In terms of impact on the spatial variation patterns, the distributions of the pollutants concentrations are similar to the distribution of the associated primary HAPs emissions, which are highly concentrated in the rural-urban fringe zones and rural suburb areas. In addition, emissions of primary pollutants from residential coal combustion are forecasted by using a scenario analysis. Generally, comprehensive measures must be taken to control residential coal combustion in Beijing. The best way to reduce the associated emissions from residential coal combustion is to use economic incentive means to promote the conversion to clean energy sources for residential heating and cooking. In areas with reliable energy supplies, the coal used

  9. Generating a representative signal of coal ash content to anticipate combustion control in a thermal power station

    International Nuclear Information System (INIS)

    Prieto-Fernandez, Ismael; Santurio-Diaz, J.M.; Folgueras-Diaz, B.; Lopez-Bobo, M. Rosario; Fernandez-Viar, P.

    2004-01-01

    This paper describes the possibilities of continuously measuring coal ash in the boiler feeding circuit of a thermal power station so that the measurement can be used as a signal for the boiler combustion control system. An installation was designed, at semi-industrial scale, that could faithfully reproduce the operation of a belt feeder. In order to measure the ash content, a natural radioactivity meter was installed and a large number of coal samples with different ranks and grain sizes were tested, eventually showing the possibility of achieving the objective

  10. High-calcium coal combustion by-products: Engineering properties, ettringite formation, and potential application in solidification and stabilization of selenium and boron

    Energy Technology Data Exchange (ETDEWEB)

    Solem-Tishmack, J.K.; McCarthy, G.J. [North Dakota State Univ., Fargo, ND (United States). Dept. of Chemistry; Docktor, B.; Eylands, K.E.; Thompson, J.S.; Hassett, D.J. [Univ. of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center

    1995-04-01

    Four high-calcium coal combustion by-products (two pulverized coal fly ashes (PCFA), a flue gas desulfurization (FGD) residue, and an atmospheric fluidized bed combustion (AFBC) fly ash), were tested for engineering properties and ability to immobilize boron and selenium. These data are needed to explore high-volume utilization in engineered structure or in solidification/stabilization (S/S) technology. Strengths of cured pastes (91 days), varied from as much as 27 MPa (3,900 psi) for one of the PCFA specimens to 4.6 MPa (670 psi) for the FGD specimen. All of the coal by-product pastes developed more than the 0.34 MPa (50 psi) required for S/S applications. Ettringite formation is important to engineering properties and S/S mechanisms. XRD on plain specimens cured for 91 days indicated that the two PCFA pastes formed 5--6% ettringite, the FGD paste formed 22%, and the AFBC paste formed 32%. The hydrating PCFA pastes showed little expansion, the FGD paste contracted slightly, and the AFBC paste expanded by 2.9% over 91 days. Se and B were spiked into the mixing water as sodium selenite, selenate and borate, and for most pastes this had little effect on strength, workability, and expansion. Leaching of ground specimens (cured for 91 days) showed a generally positive correlation between the amount of ettringite formed and resistance to Se and B leaching. Se spiked as selenate was more readily leached than Se spiked as selenite. B showed a high level of fixation.

  11. Morphology, composition, and mixing state of primary particles from combustion sources - crop residue, wood, and solid waste.

    Science.gov (United States)

    Liu, Lei; Kong, Shaofei; Zhang, Yinxiao; Wang, Yuanyuan; Xu, Liang; Yan, Qin; Lingaswamy, A P; Shi, Zongbo; Lv, Senlin; Niu, Hongya; Shao, Longyi; Hu, Min; Zhang, Daizhou; Chen, Jianmin; Zhang, Xiaoye; Li, Weijun

    2017-07-11

    Morphology, composition, and mixing state of individual particles emitted from crop residue, wood, and solid waste combustion in a residential stove were analyzed using transmission electron microscopy (TEM). Our study showed that particles from crop residue and apple wood combustion were mainly organic matter (OM) in smoldering phase, whereas soot-OM internally mixed with K in flaming phase. Wild grass combustion in flaming phase released some Cl-rich-OM/soot particles and cardboard combustion released OM and S-rich particles. Interestingly, particles from hardwood (pear wood and bamboo) and softwood (cypress and pine wood) combustion were mainly soot and OM in the flaming phase, respectively. The combustion of foam boxes, rubber tires, and plastic bottles/bags in the flaming phase released large amounts of soot internally mixed with a small amount of OM, whereas the combustion of printed circuit boards and copper-core cables emitted large amounts of OM with Br-rich inclusions. In addition, the printed circuit board combustion released toxic metals containing Pb, Zn, Sn, and Sb. The results are important to document properties of primary particles from combustion sources, which can be used to trace the sources of ambient particles and to know their potential impacts in human health and radiative forcing in the air.

  12. 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

  13. Co-combustion of peanut hull and coal blends: Artificial neural networks modeling, particle swarm optimization and Monte Carlo simulation.

    Science.gov (United States)

    Buyukada, Musa

    2016-09-01

    Co-combustion of coal and peanut hull (PH) were investigated using artificial neural networks (ANN), particle swarm optimization, and Monte Carlo simulation as a function of blend ratio, heating rate, and temperature. The best prediction was reached by ANN61 multi-layer perception model with a R(2) of 0.99994. Blend ratio of 90 to 10 (PH to coal, wt%), temperature of 305°C, and heating rate of 49°Cmin(-1) were determined as the optimum input values and yield of 87.4% was obtained under PSO optimized conditions. The validation experiments resulted in yields of 87.5%±0.2 after three replications. Monte Carlo simulations were used for the probabilistic assessments of stochastic variability and uncertainty associated with explanatory variables of co-combustion process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Optimized scheme in coal-fired boiler combustion based on information entropy and modified K-prototypes algorithm

    Science.gov (United States)

    Gu, Hui; Zhu, Hongxia; Cui, Yanfeng; Si, Fengqi; Xue, Rui; Xi, Han; Zhang, Jiayu

    2018-06-01

    An integrated combustion optimization scheme is proposed for the combined considering the restriction in coal-fired boiler combustion efficiency and outlet NOx emissions. Continuous attribute discretization and reduction techniques are handled as optimization preparation by E-Cluster and C_RED methods, in which the segmentation numbers don't need to be provided in advance and can be continuously adapted with data characters. In order to obtain results of multi-objections with clustering method for mixed data, a modified K-prototypes algorithm is then proposed. This algorithm can be divided into two stages as K-prototypes algorithm for clustering number self-adaptation and clustering for multi-objective optimization, respectively. Field tests were carried out at a 660 MW coal-fired boiler to provide real data as a case study for controllable attribute discretization and reduction in boiler system and obtaining optimization parameters considering [ maxηb, minyNOx ] multi-objective rule.

  15. Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes

    International Nuclear Information System (INIS)

    Hopkins, W.A.; Mendonca, M.T.; Congdon, J.D.

    1999-01-01

    To assess the responsiveness of the interrenal axis to stress, we injected toads exposed to coal combustion wastes and toads from an unpolluted reference site with adrenocorticotropic hormone (ACTH), as well as the vehicle alone (saline). Initial circulating levels of corticosterone in toads captured at the polluted area were significantly higher than levels in toads from the reference site. Corticosterone levels in toads from the polluted site remained high even after 2 weeks of laboratory acclimation and injection with saline. The results may suggest disruption of hepatic enzymes responsible for the metabolic clearance of steroid hormones. Injection of toads from the polluted site with ACTH had no effect on plasma corticosterone levels, whereas a similar treatment of toads from the reference site stimulated a marked increase in corticosterone. Our study provides evidence that toads exposed to coal combustion wastes may be less efficient at responding to additional environmental stressors. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Coal combustion waste management at landfills and surface impoundments 1994-2004.

    Energy Technology Data Exchange (ETDEWEB)

    Elcock, D.; Ranek, N. L.; Environmental Science Division

    2006-09-08

    On May 22, 2000, as required by Congress in its 1980 Amendments to the Resource Conservation and Recovery Act (RCRA), the U.S. Environmental Protection Agency (EPA) issued a Regulatory Determination on Wastes from the Combustion of Fossil Fuels. On the basis of information contained in its 1999 Report to Congress: Wastes from the Combustion of Fossil Fuels, the EPA concluded that coal combustion wastes (CCWs), also known as coal combustion by-products (CCBs), did not warrant regulation under Subtitle C of RCRA, and it retained the existing hazardous waste exemption for these materials under RCRA Section 3001(b)(3)(C). However, the EPA also determined that national regulations under Subtitle D of RCRA were warranted for CCWs that are disposed of in landfills or surface impoundments. The EPA made this determination in part on the basis of its findings that 'present disposal practices are such that, in 1995, these wastes were being managed in 40 percent to 70 percent of landfills and surface impoundments without reasonable controls in place, particularly in the area of groundwater monitoring; and while there have been substantive improvements in state regulatory programs, we have also identified gaps in State oversight' (EPA 2000). The 1999 Report to Congress (RTC), however, may not have reflected the changes in CCW disposal practices that occurred since the cutoff date (1995) of its database and subsequent developments. The U.S. Department of Energy (DOE) and the EPA discussed this issue and decided to conduct a joint DOE/EPA study to collect new information on the recent CCW management practices by the power industry. It was agreed that such information would provide a perspective on the chronological adoption of control measures in CCW units based on State regulations. A team of experts from the EPA, industry, and DOE (with support from Argonne National Laboratory) was established to develop a mutually acceptable approach for collecting and analyzing data

  17. Application of wasted sea-shell to desulfurizer in fluidized bed coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Naruse, Ichiro; Saito, Katsuhiro; Murakami, Takahiro

    1999-07-01

    Almost all wasted seashells consist of CaCo{sub 3}, and are similar to limestone. It would be proposed that the seashell could be applied as a desulfurizer. In this study, desulfurization characteristics of the seashell are fundamentally studied by using a thermobalance and a bubbling fluidized coal combustor with comparing the results obtained by limestone as a reference. Under the constant calcination temperature, the desulfurization efficiency for the seashells attains more than about 70% after the desulfurization period of 30 h. For the limestones, on the other hand, the desulfurization efficiency becomes only 38%. Under practical conditions of fluidized bed coal combustion, the desulfurization efficiency for the seashells also indicates higher value than that for the limestones. The desulfurization efficiency depends on the pore size distribution of CaO rather than its specific surface area. The mean pore size of the calcined seashell is about 10 times as large as that of the calcined limestones. from Scanning Electro-Microscope (SEM) photos of the surface of CaCO{sub 3}, CaO and the sulfurized particles of the seashells the large pores can be observed. In measuring cross-sectional distribution of sulfur inside the particles by using an Energy Dispersed X-ray (EDX) system, the sulfur in the sulfurized particle of limestone is only trapped near the particle surface. For the seashells, whereas, the sulfur is distributed over the whole body of particle. Desulfurization efficiency for the limestone, into which some alkali metal compounds are added, increases with increasing the concentration of alkali metal compounds added. In order of increasing effect the key elemental species to enhance the desulfurization activities are Cl, Na and K. Alkali metal compounds can enhance the desulfurization activities, due to solution of CaO in molten NaCl. This is one of the reasons why the desulfurization efficiency for the seashells improves.

  18. Plant growth response in experimental soilless mixes prepared from coal combustion products and organic waste materials

    Energy Technology Data Exchange (ETDEWEB)

    Bardhan, S.; Watson, M.; Dick, W.A. [Ohio State University, Wooster, OH (United States)

    2008-07-15

    Large quantities of organic materials such as animal manures, yard trimmings, and biosolids are produced each year. Beneficial use options for them are often limited, and composting has been proposed as a way to better manage these organic materials. Similarly, burning of coal created 125 million tons of coal combustion products (CCP) in the United States in 2006. An estimated 53 million tons of CCP were reused, whereas the remainder was deposited in landfills. By combining CCP and composted organic materials (COM), we were able to create soilless plant growth mixes with physicochemical conditions that can support excellent plant growth. An additional benefit is the conservation of natural raw materials, such as peat, which is generally used for making soilless mixes. Experimental mixes were formulated by combining CCP and COM at ratios ranging from 2:8 to 8:2 (vol/vol), respectively. Water content at saturation for the created mixes was 63% to 72%, whereas for the commercial control, it was 77%. pH values for the best performing mixes ranged between 5.9 and 6.8. Electrical conductivity and concentrations of required plant nutrient were also within plant growth recommendations for container media. Significantly (P < 0.0001) higher plant biomass growth (7%-130%) was observed in the experimental mixes compared with a commercial mix. No additional fertilizers were provided during the experiment, and reduced fertilization costs can thus accrue as an added benefit to the grower. In summary, combining CCP and COM, derived from source materials often viewed as wastes, can create highly productive plant growth mixes.

  19. Advanced coal-fueled industrial cogeneration gas turbine system -- combustion development

    Energy Technology Data Exchange (ETDEWEB)

    LeCren, R.T.

    1994-06-01

    This topical report summarizes the combustor development work accomplished under the subject contract. The objective was to develop a combustion system for the Solar 4MW Type H Centaur gas turbine generator set which was to be used to demonstrate the economic, technical and environmental feasibility of a direct coal-fueled gas turbine in a 100 hour proof-of-concept test. This program started with a design configuration derived during the CSC program. The design went through the following evolution: CSC design which had some known shortcomings, redesigned CSC now designated as the Two Stage Slagging Combustor (TSSC), improved TSSC with the PRIS evaluated in the IBSTF, and full scale design. Supporting and complimentary activities included computer modelling, flow visualization, slag removal, SO{sub x} removal, fuel injector development and fuel properties evaluation. Three combustor rigs were utilized: the TSSC, the IBSTF and the full scale rig at Peoria. The TSSC rig, which was 1/10th scale of the proposed system, consisted of a primary and secondary zone and was used to develop the primary zone performance and to evaluate SO{sub x} and slag removal and fuel properties variations. The IBSTF rig which included all the components of the proposed system was also 1/10th scale except for the particulate removal system which was about 1/30th scale. This rig was used to verify combustor performance data obtained on the TSSC and to develop the PRIS and the particulate removal system. The full scale rig initially included the primary and secondary zones and was later modified to incorporate the PRIS. The purpose of the full scale testing was to verify the scale up calculations and to provide a combustion system for the proof-of-concept engine test that was initially planned in the program.

  20. Techno-economic analysis of oxy-combustion coal-fired power plant with cryogenic oxygen storage

    OpenAIRE

    Hanak, Dawid Piotr; Manovic, Vasilije

    2017-01-01

    Around 43% of the cumulative CO2 emissions from the power sector between 2012 and 2050 could be mitigated through implementation of carbon capture and storage, and utilisation of renewable energy sources. Energy storage technologies can increase the efficiency of energy utilisation and thus should be widely deployed along with low-emission technologies. This study evaluates the techno-economic performance of cryogenic O2 storage implemented in an oxy-combustion coal-fired power plant as a mea...

  1. Geochemical characterization of arsenic-rich coal-combustion ashes buried under agricultural soils and the release of arsenic

    International Nuclear Information System (INIS)

    Veselská, Veronika; Majzlan, Juraj; Hiller, Edgar; Peťková, Katarína; Jurkovič, Ľubomír; Ďurža, Ondrej; Voleková-Lalinská, Bronislava

    2013-01-01

    Highlights: ► Sources, mineralogy and mobility of As in coal-combustion ashes were investigated. ► After a dam failure in 1965, the spilled ashes were buried under agricultural soils. ► Primary carriers of As within coal-combustion ashes are aluminosilicate glasses. ► The most probable secondary carriers of labile As are oxyhydroxides of Si, Al, and Fe. ► Arsenic stored in ashes is a long-term contamination source for the environment. - Abstract: A combination of geochemical and mineralogical methods was used to determine the concentrations, mobility, and sources of As in coal-combustion ashes and soils in the vicinity of a thermal power plant at Nováky, central Slovakia. Fresh lagooned ash, ashes buried under agricultural soils for 45 a, and the overlying soils, contain high concentrations of As ranging from 61 to 1535 mg/kg. There is no differences in the water extractable percentages of As between the fresh lagooned ash and buried ashes, which range from 3.80% to 6.70% of the total As. This small amount of As may perhaps reside on the surfaces of the ash particles, as postulated in the earlier literature, but no evidence was found to support this claim. Electron microprobe analyses show that the dominant primary As carriers are the aluminosilicate glasses enriched in Ca and Fe. The acid NH 4 + -oxalate extraction hints that the oxyhydroxides of Si, Al, and Fe are the most probable secondary carriers of labile As. The X-ray absorption spectroscopy (XAS) analyses show that As in the lagooned and buried ashes occurs mostly as As(V). The long-term burial of the coal-combustion ash under agricultural soil did not cause any major change of its chemical composition or As lability compared to the fresh lagooned ash

  2. Identification of accelerants, fuels and post-combustion residues using a colorimetric sensor array.

    Science.gov (United States)

    Li, Zheng; Jang, Minseok; Askim, Jon R; Suslick, Kenneth S

    2015-09-07

    A linear (1 × 36) colorimetric sensor array has been integrated with a pre-oxidation technique for detection and identification of a variety of fuels and post-combustion residues. The pre-oxidation method permits the conversion of fuel vapor into more detectable species and therefore greatly enhances the sensitivity of the sensor array. The pre-oxidation technique used a packed tube of chromic acid on an oxide support and was optimized in terms of the support and concentration. Excellent batch to batch reproducibility was observed for preparation and use of the disposable pre-oxidation tubes. Twenty automotive fuels including gasolines and diesel from five gasoline retailers were individually identifiable with no confusions or misclassifications in quintuplicate trials. Limits of detection were at sub-ppm concentrations for gasoline and diesel fuels. In addition, burning tests were performed on commonly used fire accelerants, and clear differentiation was achieved among both the fuels themselves and their volatile residues after burning.

  3. Effects of calcium magnesium acetate on the combustion of coal-water slurries. Final project report, 1 September 1989--28 February 1993

    Energy Technology Data Exchange (ETDEWEB)

    Levendis, Y.A.; Wise, D.; Metghalchi, H.; Cumper, J.; Atal, A.; Estrada, K.R.; Murphy, B.; Steciak, J.; Hottel, H.C.; Simons, G.

    1993-07-01

    To conduct studies on the combustion of coal water fuels (CWFs) an appropriate facility was designed and constructed. The main components were (1) a high-temperature isothermal laminar flow furnace that facilitates observation of combustion events in its interior. The design of this system and its characterization are described in Chapter 1. (2) Apparatus for slurry droplet/agglomerate particle generation and introduction in the furnace. These devices are described in Chapters 1 and 3 and other attached publications. (3) An electronic optical pyrometer whose design, construction theory of operation, calibration and performance are presented in Chapter 2. (4) A multitude of other accessories, such as particle fluidization devices, a suction thermometer, a velocimeter, high speed photographic equipment, calibration devices for the pyrometer, etc., are described throughout this report. Results on the combustion of CWF droplets and CWF agglomerates made from micronized coal are described in Chapter 3. In the same chapter the combustion of CWF containing dissolved calcium magnesium acetate (CMA) axe described. The combustion behavior of pre-dried CWF agglomerates of pulverized grain coal is contrasted to that of agglomerates of micronized coal in Chapter 4. In the same chapter the combustion of agglomerates of carbon black and diesel soot is discussed as well. The effect of CMA on the combustion of the above materials is also discussed. Finally, the sulfur capture capability of CMA impregnated micronized and pulverized bituminous coals is examined in Chapter 5.

  4. Characterization and quantification of corticosteroid-binding globulin in a southern toad, Bufo terrestris, exposed to coal-combustion-waste

    Energy Technology Data Exchange (ETDEWEB)

    Ward, C.K.; Fontes, C.; Breuner, C.W.; Mendonca, M.T. [Auburn University, Auburn, AL (USA). Dept. of Biological Science

    2007-05-15

    Corticosteroid-binding globulin (CBG) is a plasma protein that binds corticosterone and may regulate access of hormone to tissues. The role of CBG during a stress response is not clear. In this study, southern toads, Bufo terrestris, were exposed to a chronic pollutant (coal-combustion-waste), to determine changes in CBG and free corticosterone levels. Since toads exposed to chronic pollutants in previous studies did not exhibit the predicted changes in metabolic rate and mass, but did experience a significant elevation in total corticosterone, we hypothesized that CBG would likewise increase and thus, mitigate the effects of a chronic (i.e. 2 months) pollutant stressor. To conduct this study, we first characterized the properties of CBG in southern toads. After characterization, we monitored the changes in CBG, total corticosterone, and free corticosterone in male toads that were exposed to either coal-combustion-waste or control conditions. CBG increased in all groups throughout the experiment. Total corticosterone, on the other hand, was only significantly elevated at four weeks of exposure to coal-combustion-waste. The increase in CBG did not parallel the increase in total corticosterone; as a result, free corticosterone levels were not buffered by CBG, but showed a peak at four weeks similar to total corticosterone. This finding indicates that, in this species, CBG may not provide a protective mechanism during long-term pollution exposure.

  5. Use of Green Mussel Shell as a Desulfurizer in the Blending of Low Rank Coal-Biomass Briquette Combustion

    Directory of Open Access Journals (Sweden)

    Mahidin Mahidin

    2016-08-01

    Full Text Available Calcium oxide-based material is available abundantly and naturally. A potential resource of that material comes from marine mollusk shell such as clams, scallops, mussels, oysters, winkles and nerites. The CaO-based material has exhibited a good performance as the desulfurizer oradsorbent in coal combustion in order to reduce SO2 emission. In this study, pulverized green mussel shell, without calcination, was utilized as the desulfurizer in the briquette produced from a mixture of low rank coal and palm kernel shell (PKS, also known as bio-briquette. The ratio ofcoal to PKS in the briquette was 90:10 (wt/wt. The influence of green mussel shell contents and combustion temperature were examined to prove the possible use of that materialas a desulfurizer. The ratio of Ca to S (Ca = calcium content in desulfurizer; S = sulfur content in briquette werefixed at 1:1, 1.25:1, 1.5:1, 1.75:1, and 2:1 (mole/mole. The burning (or desulfurization temperature range was 300-500 °C; the reaction time was 720 seconds and the air flow rate was 1.2 L/min. The results showed that green mussel shell can be introduced as a desulfurizer in coal briquette or bio-briquette combustions. The desulfurization process using that desulfurizer exhibited the first order reaction and the highest average efficiency of 84.5%.

  6. Mercury and Air Toxic Element Impacts of Coal Combustion By-Product Disposal and Utilizaton

    Energy Technology Data Exchange (ETDEWEB)

    David Hassett; Loreal Heebink; Debra Pflughoeft-Hassett; Tera Buckley; Erick Zacher; Mei Xin; Mae Sexauer Gustin; Rob Jung

    2007-03-31

    The University of North Dakota Energy & Environmental Research Center (EERC) conducted a multiyear study to evaluate the impact of mercury and other air toxic elements (ATEs) on the management of coal combustion by-products (CCBs). The ATEs evaluated in this project were arsenic, cadmium, chromium, lead, nickel, and selenium. The study included laboratory tasks to develop measurement techniques for mercury and ATE releases, sample characterization, and release experiments. A field task was also performed to measure mercury releases at a field site. Samples of fly ash and flue gas desulfurization (FGD) materials were collected preferentially from full-scale coal-fired power plants operating both without and with mercury control technologies in place. In some cases, samples from pilot- and bench-scale emission control tests were included in the laboratory studies. Several sets of 'paired' baseline and test fly ash and FGD materials collected during full-scale mercury emission control tests were also included in laboratory evaluations. Samples from mercury emission control tests all contained activated carbon (AC) and some also incorporated a sorbent-enhancing agent (EA). Laboratory release experiments focused on measuring releases of mercury under conditions designed to simulate CCB exposure to water, ambient-temperature air, elevated temperatures, and microbes in both wet and dry conditions. Results of laboratory evaluations indicated that: (1) Mercury and sometimes selenium are collected with AC used for mercury emission control and, therefore, present at higher concentrations than samples collected without mercury emission controls present. (2) Mercury is stable on CCBs collected from systems both without and with mercury emission controls present under most conditions tested, with the exception of vapor-phase releases of mercury exposed to elevated temperatures. (3) The presence of carbon either from added AC or from unburned coal can result in mercury

  7. Renew, reduce or become more efficient? The climate contribution of biomass co-combustion in a coal-fired power plant

    NARCIS (Netherlands)

    Miedema, Jan H.; Benders, Rene M. J.; Moll, Henri C.; Pierie, Frank

    2017-01-01

    Within this paper, biomass supply chains, with different shares of biomass co-combustion in coal fired power plants, are analysed on energy efficiency, energy consumption, renewable energy production, and greenhouse gas (GHG) emissions and compared with the performance of a 100% coal supply chain

  8. Study on the Relationship between the Inhalable Fine Particulate Matter of Xuanwei Coal Combustion and Lung Cancer

    Directory of Open Access Journals (Sweden)

    Jiapeng YANG

    2015-07-01

    Full Text Available Background and objective The high incidence of lung cancer in Xuanwei, China, has become an important restricting factor for livelihood development, thus exerting local social and economic impacts. Coal is the main fuel of the local community and also the main source of indoor pollution. This study aims to explore the coal combustion inhalable fine particulate matter (PM2.5 and its component output differences in different areas of Xuanwei, Yunnan. Moreover, the aim of this study is to investigate the relationship between inhalation of fine particles and high incidence of local lung cancer. Methods For combustion test, coal mines designated as C1, K7 and M30 were collected from LaoLin Colliery of Laibing Town, Huchang Colliery of Baoshan Town, and Taiping Colliery of Wenxing Town in Xuanwei, respectively. PM2.5 of indoor air was weighed, analyzed for elemental composition, and morphologically compared. The pathological specimen of lung cancer patients in Xuanwei who underwent operation was observed through electron microscope. Results The PM2.5 concentrations in indoor air were (8.244 ±1.460 mg/m3 (C1, (5.066±0.984 mg/m3 (K7, and (5.071±1.460 mg/m3 (M30. The differences among pairwise comparisons were statistically significant (P=0.029. The filter impurities of C1 coal seam primarily include Si- and O-enriched compounds. Moreover, three membranes that comprised other elements, including C, S, and Si, were observed. These membranes were evident from the aggregation of silica and a Ca-Al membrane. Compared with that of other coal seams, C1 coal generated a mass of impurities, in which several particles have irregular shape. We found nanoscale fine particles in some specimens of Xuanwei lung cancer patients. Conclusion The produced combustion of C1 coal was different from that of K7 and M30 coal. PM2.5 composition may be associated with the high local incidence of lung cancer.

  9. Characterization of residues from waste combustion in fluidized bed boilers. Evaluation report

    International Nuclear Information System (INIS)

    Hagman, U.; Elander, P.

    1996-04-01

    In this report a thorough characterization of the solid residues from municipal solid waste combustion in a Kvaerner EnviroPower bubbling fluidized bed boiler in Lidkoeping, is presented. Three different end products are generated, namely bottom ash, cyclone ash, and filter ash. The bottom ash, consisting of bed ash and hopper ash, is screened and useful bed material recycled. In the characterization, also the primary constituents bed ash and hopper ash have been included. A chemical characterization have been performed including total inorganic contents, content of unburnt matter, leaching behaviour (availability tests, column tests, pH-static tests) and leaching tests according to certain standards for classification (AFX31-210, DIN38414, TCLP). Physical characterization have included grain size distribution, grain density, compaction properties and stabilization of cyclone ash with subsequent testing of comprehensive strength and saturated hydraulic conductivity. From an environmental point of view, the quality of the bottom ash and probably the cyclone ash from fluidized bed combustion as determined in this study, indicate a potential for utilization. Utilization of the bottom ash could be accepted in certain countries, e.g. France, according to their current limit values. In other countries, e.g. Sweden, no general limit values are given and utilization have to be applied for in each case. The judgement is then based, not only on total contents in the residue and its leaching behaviour, but also on the specific environmental conditions at the site. 7 refs, 17 figs, 12 tabs

  10. Coal combustion by-product quality at two stoker boilers: Coal source vs. fly ash collection system design

    Energy Technology Data Exchange (ETDEWEB)

    Mardon, Sarah M. [Kentucky Department for Environmental Protection, Division of Water, Frankfort, KY 40601 (United States); Hower, James C. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); O' Keefe, Jennifer M.K. [Morehead State University, Department of Physical Sciences, Morehead, KY 40351 (United States); Marks, Maria N. [Environmental Consulting Services, Lexington, KY 40508 (United States); Hedges, Daniel H. [University of Kentucky, Department of Earth and Environmental Sciences, Lexington, KY 40506 (United States)

    2008-09-15

    Fly ashes from two stoker boilers burning Pennsylvanian Eastern Kentucky high volatile A bituminous coal blends were examined for their petrology and chemistry. The source coals have similar trace element contents. One of the ash collection systems was retrofitted with a baghouse (fabric filter) system, collecting a finer fly ash at a cooler flue gas temperature than the plant that has not been reconfigured. The baghouse ash has a markedly higher trace element content than the coarser fly ash from the other plant. The enhanced trace element content is most notable in the As concentration, reaching nearly 9000 ppm (ash basis) for one of the collection units. Differences in the ash chemistry are not due to any substantial differences in the coal source, even though the coal sources were from different counties and from different coal beds, but rather to the improved pollution control system in the steam plant with the higher trace element contents. (author)

  11. The identification of unusual microscopic features in coal and their derived chars: Influence on coal fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Valentim, B. [Centro de Geologia da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Lemos de Sousa, M.J. [Centro de Geologia da Universidade do Porto, Praca de Gomes Teixeira, 4099-002 Porto (Portugal); Abelha, P.; Boavida, D.; Gulyurtlu, I. [Departamento de Engenharia Energetica e Controlo Ambiental (DEECA), Instituto Nacional de Engenharia, Tecnologia e Inovacao (INETI), Estrada do Paco do Lumiar, 22, Edif. J, 1649-038, Lisboa (Portugal)

    2006-06-06

    During the petrographic study of seven feed coals from different origins, it was found that these coals presented microfeatures such as: material size, shape, weathering, thermally affected particles and contamination. After devolatilization under fluidized bed conditions, some chars presented the consequences of the above mentioned microfeatures, i.e., unreacted coal, unswelled particles, coatings and microstratification. Since the amounts of the microfeatures observed were low (less than 1%), the present study is essentially observational/descriptional. However, it seems very likely, from the observations that were made, that the occurrence of one or more of these microfeatures in coal, depending on their kind and abundance, may have significant effect on the coal devolatilization. (author)

  12. 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 im...

  13. Correlation between the coal quality from 'Suvodol' and briquetting processes for coals, peat and other combustible materials (coal deposit in Macedonia)

    International Nuclear Information System (INIS)

    Damjanovski, Dragan; Popovski, Dushko; Mitrevski, Pece

    1997-01-01

    In this paper the regression equations for the characteristics of Suvodol coal and the technological parameters of obtained briquets are given. It is shown that correlations between the coal characteristics are linear, while correlations between briquetting parameters are nonlinear

  14. The emissions of VOCs during co-combustion of coal with different waste materials in a fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    I. Gulyurtlu; P. Abelha; A. Gregorio; A. Garcia-Garcia; D. Boavida; A. Crujeira; I. Cabrita [DEECA-INETI, Lisbon (Portugal)

    2004-06-01

    The combustion of different fuels gives rise to the formation of small but appreciable amounts of volatile organic compounds (VOCs). They basically result from incomplete combustion and their emissions have negative repercussions on health and on the environment in general. As their measurement is difficult, costly, and very time-consuming, very little is reported on the emissions of VOCs from combustion installations. In this study, various blends of two different coals with several wastes were burned in a pilot-scale fluidized bed combustor and measurements of VOCs at several locations along the combustor height as well as just before the stack were carried out. The results demonstrate that the parameters important for the formation of VOCs are temperature, excess air levels, and the effectiveness of the mixing of air with fuel. Furthermore, it was observed that coal was the principal source of VOCs, but the combustion of volatiles from fuels such as biomass, occurring in the freeboard, was important in reducing the emissions of VOCs to almost zero. 8 refs., 6 figs., 6 tabs.

  15. Prediction of oxy-coal combustion through an optimized weighted sum of gray gases model

    International Nuclear Information System (INIS)

    Kangwanpongpan, Tanin; Corrêa da Silva, Rodrigo; Krautz, Hans Joachim

    2012-01-01

    Oxy-fuel combustion is considered as one of promising options for carbon dioxide capture in future coal power plants. Currently models available in CFD codes fail to predict accurately the radiative heat transfer in oxy-fuel cases due to higher pressure of carbon dioxide and water vapor. This paper concerns numerical investigation applying three band formulations aiming an accurate prediction of radiative properties. The radiative heat transfer is calculated by discrete ordinate method coupled with a weighted sum of gray gases model. The first case relates to the domain-based approach using air-fired parameters. In the last two cases, the optimized parameters of 3 and 4 gray gases fitted to oxy-fired conditions are implemented through a non-gray gases approach. Results applying these set of parameters are evaluated through a comparison with experimental data. Discrepancies between the predicted and measured velocity and O 2 concentration are found mainly close to the burner due to shortcomings of the turbulence model and inaccurate thermochemical closure. The gas flame temperatures are better predicted by the optimized parameters for oxy-fuel conditions, which are considerably lower than the values calculated by the air-fired parameters. Similar trends are observed when the radiative heat fluxes at the lateral wall are compared.

  16. A preliminary high-pressure thermogravimetric study of combustion reactivity of a Collie coal char

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Yii Leng; Zhang, Zhezi; Zhu, Mingming; Zhang, Dongke [Western Australia Univ., Crawley, WA (Australia). Centre for Energy (M473); Luan, Chao [Western Australia Univ., Crawley, WA (Australia). Centre for Energy (M473); Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering; You, Changfu [Tsinghua Univ., Beijing (China). Inst. of Thermal Engineering

    2013-07-01

    The effect of pressure(up to 20 bar)on the reactivity of a char(150-160 {mu}m) produced from Western Australian Collie coal has been studied using a high-pressure thermogravimetric analyser (HP TGA). The pressure demonstrated a positive effect in enhancing char combustion reactivities.Kinetic parameters have been determined from the experimental data.The apparent reaction order was found to be approximately 0.7 and the apparent activation energies were 91.0 kJ/mol at atmospheric pressure and 1.5 kJ/mol at an elevated pressure(10 bar),indicating a shift in the control regimes of the reaction at elevated pressures.The lumped effect of the sample size, bulk diffusion,interparticle and intraparticle diffusion at the elevated pressures played an important role in reducing the mass transfer during the HP-TGA experimentation.Thus the activation energy calculated at elevated pressures may not represent the intrinsic activation energy of the char particles but the apparent values of the bulk of the samples.

  17. Investigation of coal combustion by-product utilization for oyster reef development in Texas bay waters

    International Nuclear Information System (INIS)

    Baker, W.B. Jr.; Ray, S.M.; Landry, A.M. Jr.

    1991-01-01

    Houston Lighting and Power Company (HL and P), Texas A and M University at Galveston and JTM Industries, Inc. initiated research in May 1988 and coordinated it with state and federal resource protection agencies to investigate the use of certain HL and P coal combustion by-products (CCBP) for enhancing and creating oyster reefs. Initial research involved determining and optimum mix design based on compressive strength, leaching potential, biofouling success, and cost. CCBP material was found to exceed compressive strength criterion (300 psi for at sign 14 days) and was not a significant leaching source. Candidate mix designs and oyster shell controls were exposed to hatchery-reared oyster larvae to determine spat setability and biofouling success. Larvae setting on CCBP substrate developed into spat and grew at a rate comparable to that for larvae on controls. Since all candidate mix designs exhibited excellent biofouling, an optimum design was chosen based on strength and material cost factors. Chemical analyses conducted to determine materials did not significantly contribute to the trace element load in oysters. Development of oyster cultch material was initiated with input from commercial 2.5 to 7.6 cm (1 to 3 inch) diameter pellets which are irregularly shaped and rough textured. These pellets greatly enhance water circulation, provide maximum setting potential for oyster larvae, and maximize the surface area to volume potential of the CCBP material

  18. Improving lithium-ion battery performances by adding fly ash from coal combustion on cathode film

    Energy Technology Data Exchange (ETDEWEB)

    Dyartanti, Endah Retno; Jumari, Arif, E-mail: arifjumari@yahoo.com; Nur, Adrian; Purwanto, Agus [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    A lithium battery is composed of anode, cathode and a separator. The performance of lithium battery is also influenced by the conductive material of cathode film. In this research, the use of fly ash from coal combustion as conductive enhancer for increasing the performances of lithium battery was investigated. Lithium iron phosphate (LiFePO{sub 4}) was used as the active material of cathode. The dry fly ash passed through 200 mesh screen, LiFePO{sub 4} and acethylene black (AB), polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent were mixed to form slurry. The slurry was then coated, dried and hot pressed to obtain the cathode film. The ratio of fly ash and AB were varied at the values of 1%, 2%, 3%, 4% and 5% while the other components were at constant. The anode film was casted with certain thickness and composition. The performance of battery lithium was examined by Eight Channel Battery Analyzer, the composition of the cathode film was examined by XRD (X-Ray Diffraction), and the structure and morphology of the anode film was analyzed by SEM (Scanning Electron Microscope). The composition, structure and morphology of cathode film was only different when fly ash added was 4% of AB or more. The addition of 2% of AB on cathode film gave the best performance of 81.712 mAh/g on charging and 79.412 mAh/g on discharging.

  19. Fundamental study of the pulverized coal char combustion in oxyfuel mode with drop tube furnace

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Takamasa; Takafuji, Makoto; Suda, Toshiyuki; Fujimori, Toshiro [Heat and Fluid Dynamics Department, Yokohama (Japan)

    2013-07-01

    The combustion characteristics of coal char particles in either O{sub 2}/N{sub 2} or O{sub 2}/CO{sub 2} conditions were experimentally investigated. Especially, the char burnout, the char particle temperature and the shrinkage of the char particles were discussed. A Drop Tube Furnace (DTF: whose wall temperature was set at 873, 923 and 973 K) was used as the experimental apparatus. The experimental results revealed that, in equivalent oxygen concentration, the char burnout and the char particle temperature were higher in O{sub 2}/N{sub 2} conditions than those in O{sub 2}/CO{sub 2} conditions. The shrinkage of the char particle did not show the large difference in either O{sub 2}/N{sub 2} or O{sub 2}/CO{sub 2} conditions. Up to 15% of char burnout, the char particle diameters were reduced gradually. Up to 80% of char burnout, the char particle diameters were not changed. This is supposed that the chemical reaction is mainly occurred not on the external surface but on the internal surface of the char particle. Over 80% of char burnout, sudden shrinkage could be seen. Finally, an empirical equation for the prediction of the char particle shrinkage was introduced. Further investigation is required in high operating temperature, where CO{sub 2} gasification may have a large influence on the char burnout.

  20. Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

    Energy Technology Data Exchange (ETDEWEB)

    K. Ladwig

    2005-12-31

    The overall objective of this project was to evaluate the impact of key constituents captured from power plant air streams (principally arsenic and selenium) on the disposal and utilization of coal combustion products (CCPs). Specific objectives of the project were: (1) to develop a comprehensive database of field leachate concentrations at a wide range of CCP management sites, including speciation of arsenic and selenium, and low-detection limit analyses for mercury; (2) to perform detailed evaluations of the release and attenuation of arsenic species at three CCP sites; and (3) to perform detailed evaluations of the release and attenuation of selenium species at three CCP sites. Each of these objectives was accomplished using a combination of field sampling and laboratory analysis and experimentation. All of the methods used and results obtained are contained in this report. For ease of use, the report is subdivided into three parts. Volume 1 contains methods and results for the field leachate characterization. Volume 2 contains methods and results for arsenic adsorption. Volume 3 contains methods and results for selenium adsorption.

  1. Coal combustion by-product (CCB) utilization in turfgrass sod production

    Energy Technology Data Exchange (ETDEWEB)

    Schlossberg, M.J.; Miller, W.P. [University of Georgia, Athens, GA (United States). Dept. of Crop & Soil Science

    2004-04-01

    Coal combustion by-products (CCB) are produced nationwide, generating 101 Mg of waste annually. Though varied, the majority of CCB are crystalline alumino-silicate minerals. Both disposal costs of CCB and interest in alternative horticultural/agricultural production systems have increased recently. Field studies assessed the benefit of CCB and organic waste/product mixtures as supplemental soil/growth media for production of hybrid bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy) sod. Growth media were applied at depths of 2 to 4 cm (200 to 400 m{sup 3}{center_dot}ha{sup -1}) and vegetatively established by sprigging. Cultural practices typical of commercial methods were employed over 99- or 114-day growth periods. Sod was monitored during these propagation cycles, then harvested, evaluated, and installed offsite in a typical lawn-establishment method. Results showed mixtures of CCB and biosolids as growth media increased yield of biomass, with both media and tissue having greater nutrient content than the control media. Volumetric water content of CCB-containing media significantly exceeded that of control media and soil included with a purchased bermudagrass sod. Once installed, sod grown on CCB-media did not differ in rooting strength from control or purchased sod. When applied as described, physicochemical characteristics of CCB-media are favorable and pose little environmental risk to soil or water resources.

  2. Impact of coal combustion waste on the microbiology of a model aquifer

    International Nuclear Information System (INIS)

    Brunning, J.S.; Caldwell, D.E.; Lawrence, J.R.; Roberts, R.D.

    1994-01-01

    The effects of water infiltration into an alkaline coal combustion waste burial site on the chemical and microbiological aspects of a meso-scale (2,44 m diameter x 4.6 m, height, 65 tonne) model aquifer were analyzed. The spatial and temporal effects of the alkaline leachate on microbial activity, numbers and diversity were examined in the model and compared with uncontaminated control materials. Within the saturated zone below the waste there was a pH gradient from 12.4 at the water table, immediately below the waste, to 6.0 at 3.5 meters from the waste, and elevated levels of arsenic and strontium in the pore waters. Microtox testing of the contaminated pore waters indicated high toxicity (a gamma value of 1 at dilutions of 45 to 110 fold). The leachate contamination was associated with a reduction in bacterial ( 3 H) leucine incorporation from a high of 265 fmol g -1 h -1 in sediments below the contaminant plume to undetectable in the contaminated zone. In comparison, leucine incorporation rates in control column sediments were 899 fmol g -1 h -1 . Similar toxic effects were evident in reduced total direct and culturable counts of bacteria. Observations also indicated a reduction in microbial diversity and development of alkaline-tolerant microbial communities. These results indicated that any failure of confinement technologies at disposal sites would adversely affect both the chemistry and microbiology of the underlying saturated zone. 43 refs., 7 figs., 2 tabs

  3. Use of nitrogen stable isotope analysis to understand char nitrogen evolution during the fluidized-bed co-combustion of coal and sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Ana Arenillas; Roberto Garcia; Chenggong Sun; Colin E. Snape; Angel H. Moreno; Fernando Rubiera; Jose J. Pis [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

    2005-04-01

    NOx emissions from sewage sludge combustion are a concern, because of the usually high nitrogen content of this fuel. The interactions during co-combustion in a fluidized-bed reactor of sewage sludge and a bituminous coal were evaluated, in relation to the nitrogen evolution during the combustion process. The nitrogen stable isotope measurements provide novel results regarding the tracing of nitrogen during combustion. Our preliminary results show that the co-combustion chars retain more nitrogen than expected, with the additional nitrogen being mainly derived from the sludge. Additional measurements are planned on the resultant co-combustion gases, to aid source apportionment of the NOx arising from coal/sewage interactions. 14 refs., 3 figs., 2 tabs.

  4. Oxy-fuel combustion of coal and biomass, the effect on radiative and convective heat transfer and burnout

    Energy Technology Data Exchange (ETDEWEB)

    Smart, John P.; Patel, Rajeshriben; Riley, Gerry S. [RWEnpower, Windmill Hill Business Park, Whitehill Way, Swindon, Wiltshire SN5 6PB, England (United Kingdom)

    2010-12-15

    This paper focuses on results of co-firing coal and biomass under oxy-fuel combustion conditions on the RWEn 0.5 MWt Combustion Test Facility (CTF). Results are presented of radiative and convective heat transfer and burnout measurements. Two coals were fired: a South African coal and a Russian Coal under air and oxy-fuel firing conditions. The two coals were also co-fired with Shea Meal at a co-firing mass fraction of 20%. Shea Meal was also co-fired at a mass fraction of 40% and sawdust at 20% with the Russian Coal. An IFRF Aerodynamically Air Staged Burner (AASB) was used. The thermal input was maintained at 0.5 MWt for all conditions studied. The test matrix comprised of varying the Recycle Ratio (RR) between 65% and 75% and furnace exit O{sub 2} was maintained at 3%. Carbon-in-ash samples for burnout determination were also taken. Results show that the highest peak radiative heat flux and highest flame luminosity corresponded to the lowest recycle ratio. The effect of co-firing of biomass resulted in lower radiative heat fluxes for corresponding recycle ratios. Furthermore, the highest levels of radiative heat flux corresponded to the lowest convective heat flux. Results are compared to air firing and the air equivalent radiative and convective heat fluxes are fuel type dependent. Reasons for these differences are discussed in the main text. Burnout improves with biomass co-firing under both air and oxy-fuel firing conditions and burnout is also seen to improve under oxy-fuel firing conditions compared to air. (author)

  5. Combustion

    CERN Document Server

    Glassman, Irvin

    1987-01-01

    Combustion, Second Edition focuses on the underlying principles of combustion and covers topics ranging from chemical thermodynamics and flame temperatures to chemical kinetics, detonation, ignition, and oxidation characteristics of fuels. Diffusion flames, flame phenomena in premixed combustible gases, and combustion of nonvolatile fuels are also discussed. This book consists of nine chapters and begins by introducing the reader to heats of reaction and formation, free energy and the equilibrium constants, and flame temperature calculations. The next chapter explores the rates of reactio

  6. Distribution of Clay Minerals in Light Coal Fractions and the Thermal Reaction Products of These Clay Minerals during Combustion in a Drop Tube Furnace

    Directory of Open Access Journals (Sweden)

    Sida Tian

    2016-06-01

    Full Text Available To estimate the contribution of clay minerals in light coal fractions to ash deposition in furnaces, we investigated their distribution and thermal reaction products. The light fractions of two Chinese coals were prepared using a 1.5 g·cm−3 ZnCl2 solution as a density separation medium and were burned in a drop-tube furnace (DTF. The mineral matter in each of the light coal fractions was compared to that of the relevant raw coal. The DTF ash from light coal fractions was analysed using hydrochloric acid separation. The acid-soluble aluminium fractions of DTF ash samples were used to determine changes in the amorphous aluminosilicate products with increasing combustion temperature. The results show that the clay mineral contents in the mineral matter of both light coal fractions were higher than those in the respective raw coals. For the coal with a high ash melting point, clay minerals in the light coal fraction thermally transformed more dehydroxylation products compared with those in the raw coal, possibly contributing to solid-state reactions of ash particles. For the coal with a low ash melting point, clay minerals in the light coal fraction produced more easily-slagging material compared with those in the raw coal, playing an important role in the occurrence of slagging. Additionally, ferrous oxide often produces low-melting substances in coal ash. Due to the similarities of zinc oxide and ferrous oxide in silicate reactions, we also investigated the interactions of clay minerals in light coal fractions with zinc oxide introduced by a zinc chloride solution. The extraneous zinc oxide could react, to a small extent, with clay minerals in the coal during DTF combustion.

  7. Thermal behavior of the major constituents of some agricultural biomass residues during pyrolysis and combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Haykiri-Acma, H. [Istanbul Technical Univ., Istanbul (Turkey). Dept. of Chemical Engineering, Chemical and Metallurgical Engineering Faculty

    2006-07-01

    The importance of woody agricultural waste as a renewable energy source was discussed with reference to its low cost, abundance, and carbon dioxide neutrality. Direct combustion of biomass waste fuels is not recommended due to its low density, high moisture content and low calorific energy. Rather, thermal conversion processes such as pyrolysis, gasification or carbonization are preferred for biomass. The performance and the energy recovery potentials of these processes depend on the process conditions as well as the physical and chemical properties of the biomass species. Therefore, the structure and components of biomass must be known. In this study, agricultural biomass samples of almond shell, walnut shell, hazelnut shell, rapeseed, olive residue, and tobacco waste were first analytically treated to remove extractive matter to obtain extractive-free samples. Specific analytic procedures were then applied to biomass samples in order to isolate their individual biomass constituents such as lignin and holocellulose. Untreated biomass samples and their isolated constituents were exposed to non-isothermal pyrolysis and combustion processes in a thermogravimetric analyzer. Pyrolysis experiments were conducted under dynamic nitrogen atmospheres of 40 mL-min, while dynamic dry air atmosphere with the same flow rate was applied in the combustion experiments. The study showed that the pyrolysis and combustion characteristics of the biomass samples differed depending on their properties. Aliphatic and oxygen rich holocellulose and cellulose were found to be the reactive components in biomass. Lignin was more stable during thermal processes. When extractive matter from the biomass samples was removed, pyrolysis at lower temperatures was terminated. 10 refs., 4 tabs., 3 figs.

  8. Solid residues

    International Nuclear Information System (INIS)

    Mulder, E.; Duin, P.J. van; Grootenboer, G.J.

    1995-01-01

    A summary is presented of the many investigations that have been done on solid residues of atmospheric fluid bed combustion (AFBC). These residues are bed ash, cyclone ash and bag filter ash. Physical and chemical properties are discussed and then the various uses of residues (in fillers, bricks, gravel, and for recovery of aluminium) are summarised. Toxicological properties of fly ash and stack ash are discussed as are risks of pneumoconiosis for workers handling fly ash, and contamination of water by ashes. On the basis of present information it is concluded that risks to public health from exposure to emissions of coal fly ash from AFBC appear small or negligible as are health risk to workers in the coal fly ash processing industry. 35 refs., 5 figs., 12 tabs