Occurrence of trace elements in respirable coal dust

International Nuclear Information System (INIS)

Sahoo, B.N.

1991-01-01

Inhalation of fine particles of coal dust contributes significantly to the occurrence of the disease, pneumoconiosis, prevailing in coal mining community. It is not presently known whether only the coal dust or specific chemical compounds or synergistic effects of several compounds associated with respirable coal dust is responsible for the disease, pneumoconiosis. The present paper describes the quantitative determination of ten minor and trace elements in respirable coal dust particles by atomic absorption spectrophotometric methods. The respirable coal dust samples are collected at the mine atmosphere during drilling in coal scams by using Messrs. Casella's Hexlet apparatus specially designed and fitted with horizontal elutriator to collect the respirable coal dust fraction simulating as near as possible to the lung's retention of the coal miners. After destruction of organic matter by wet oxidation and filtering off clay and silica, Fe, Ca, Mg, Na, K, Mn, Cu, Zn, Cd, and Ni were determined directly in the resulting solution by atomic absorption spectrophotometric procedures. The results show that the trace metals are more acute in lower range of size spectrum. Correlation coefficient, enrichment factor and linear regression values and their inverse relationship between the slope and EF values suggest that, in general, the trace metals in respirable particulates are likely to be from coal derived source if their concentrations are likewise high in the coal. The trace metal analytical data of respirable particulates fitted well to the linear regressive equation. The results of the studies are of importance as it may throw some light on the respirable lung disease 'pneumoconiosis' which are predominant in coal mining community. (author). 13 refs., 6 tabs

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.)

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures.

Science.gov (United States)

Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

2016-04-15

The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Dust Combustion Safety Issues for Fusion Applications

Energy Technology Data Exchange (ETDEWEB)

L. C. Cadwallader

2003-05-01

This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

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

The fate of injectant coal in blast furnaces: The origin of extractable materials of high molecular mass in blast furnace carryover dusts

Energy Technology Data Exchange (ETDEWEB)

Dong, S.N.; Wu, L.; Paterson, N.; Herod, A.A.; Dugwell, D.R.; Kandiyoti, R. [University of London Imperial College of Science & Technology, London (United Kingdom). Dept. of Chemical Engineering

2005-07-01

The aim of the work was to investigate the fate of injectant coal in blast furnaces and the origin of extractable materials in blast furnace carryover dusts. Two sets of samples including injectant coal and the corresponding carryover dusts from a full sized blast furnace and a pilot scale rig have been examined. The samples were extracted using 1-methyl-2-pyrrolidinone (NMP) solvent and the extracts studied by size exclusion chromatography (SEC). The blast furnace carryover dust extracts contained high molecular weight carbonaceous material, of apparent mass corresponding to 10{sup 7}-10{sup 8} u, by polystyrene calibration. In contrast, the feed coke and char prepared in a wire mesh reactor under high temperature conditions did not give any extractable material. Meanwhile, controlled combustion experiments in a high-pressure wire mesh reactor suggest that the extent of combustion of injectant coal in the blast furnace tuyeres and raceways is limited by time of exposure and very low oxygen concentration. It is thus likely that the extractable, soot-like material in the blast furnace dust originated in tars is released by the injectant coal. Our results suggest that the unburned tars were thermally altered during the upward path within the furnace, giving rise to the formation of heavy molecular weight (soot-like) materials.

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures

Energy Technology Data Exchange (ETDEWEB)

Addai, Emmanuel Kwasi, E-mail: emmanueladdai41@yahoo.com; Gabel, Dieter; Krause, Ulrich

2016-04-15

Highlights: • Ignition sensitivity of a highly flammable dust decreases upon addition of inert dust. • Minimum ignition temperature of a highly flammable dust increases when inert concentration increase. • Minimum ignition energy of a highly flammable dust increases when inert concentration increase. • The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. - Abstract: The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%.

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures

International Nuclear Information System (INIS)

Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

2016-01-01

Highlights: • Ignition sensitivity of a highly flammable dust decreases upon addition of inert dust. • Minimum ignition temperature of a highly flammable dust increases when inert concentration increase. • Minimum ignition energy of a highly flammable dust increases when inert concentration increase. • The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. - Abstract: The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%.

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.

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 ...

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.

Research on the Combustion Characteristics and Kinetic Analysis of the Recycling Dust for a COREX Furnace

Directory of Open Access Journals (Sweden)

Haiyang Wang

2017-02-01

Full Text Available Thermogravimetric analysis of recycling dust (RD from the melter gasifier of COREX, coke1 (C-1, coke2 (C-2 and coal char (CC under 70% oxygen atmosphere was carried out using thermal balance. The chemical composition and physical structure of the samples were investigated. The characteristic temperatures and comprehensive combustion characteristic indexes were calculated and kinetic parameters during the combustion process were calculated as well using a distributed activation energy model (DAEM. The results show that the carbon in the recycling dust originates from unconsumed CC and coke fines, and the average stacking height of carbon in RD is larger than that of C-1, C-2 and CC. The conversion curves of RD are different from those of C-1, C-2 and CC, and there are two peaks in the RD conversion rate curves. The combustion profiles of RD moves to a higher temperature zone with increasing heating rates. The average activation energies of their combustion process for RD, C-1, C-2 and CC range from 191.84 kJ/mol to 128.31 kJ/mol. The activation energy for recycling dust increases as the fractional conversion increases, but the value for C-1, C-2 and CC decreases with increasing conversion, indicating different combustion mechanisms.

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

Mice housed on coal dust-contaminated sand: A model to evaluate the impacts of coal mining on health

Energy Technology Data Exchange (ETDEWEB)

Caballero-Gallardo, Karina, E-mail: kcaballerog@unicartagena.edu.co; Olivero-Verbel, Jesus, E-mail: joliverov@unicartagena.edu.co

2016-03-01

Coal dust is the most important air pollutant in coal mining in regards to producing deleterious health effects. It permeates the surrounding environment threatening public health. The aim of this study was to evaluate the toxic effects associated with exposure to sand contaminated with coal dust particles below 38 μm in diameter, obtained from a mineral sample collected in the largest coal mine in South America, La Loma, Cesar, Colombia. Sterilized sand was spiked with coal dust to obtain concentrations ranging from zero to 4% coal dust. To model natural exposure, mice were housed for eight weeks in boxes containing this mixture as bedding after which, they were euthanized and blood and tissue samples were collected. Real time PCR analysis revealed an increase in Cyp1A1 mRNA for living on sand with coal dust concentrations greater than 2% compared to mice living on sand without coal dust. Unexpectedly, for mice on coal dust-polluted sand, Sod1, Scd1 and Nqo1 hepatic mRNA were downregulated. The Comet assay in peripheral blood cells and the micronucleus test in blood smears, showed a significant potential genotoxic effect only at the highest coal dust concentration. Histopathological analysis revealed vascular congestion and peribronchial inflammation in the lungs. A dose–response relationship for the presence of hepatic steatosis, vacuolization and nuclei enlargements was observed in the exposed animals. The data suggest living on a soil polluted with coal dust induces molecular, cellular and histopathological changes in mice. Accordingly, the proposed model can be used to identify deleterious effects of exposure to coal dust deposited in soils that may pose health risks for surrounding wildlife populations. - Highlights: • Mice were exposed to coal dust-contaminated sand. • mRNA Markers for PAH exposure, lipid metabolism and oxidative stress increased. • ALT activity in plasma increased at the highest exposure to coal dust. • Liver tissues of exposed

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

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.

Preparation and co-combustion of whole plants in a coal dust furnace; Aufbereitung und Mitverbrennung von Ganzpflanzen mit Steinkohle in einer Staubfeuerung

Energy Technology Data Exchange (ETDEWEB)

Siegle, V; Spliethoff, H; Hein, K R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen (IVD)

1997-12-31

Co-combustion is a favourable and simple way of utilizing biomass. Owing to the high energy density of grains, whole plants must be ground very thoroughly for use in a coal dust furnace. This can be done with low energy consumption in a hammer mill. In addition, multifuel swirl burners permit selective supply of fuel and low-NO{sub x} combustion. The fuel with the highest nitrogen content should be blown into the inner recirculation zone. (orig) [Deutsch] Die Mitverbrennung von Biomasse ist eine guenstige und schnell zu realisierende Moeglichkeit, Biomasse in grossem Umfang zu nutzen. Um Ganzpflanzen in einer Staubfeuerung mitverbrennen zu koennen, muessen diese aufgrund der hohen Energiedichte der Koerner sehr fein aufgemahlen werden. Dies ist mit einer Hammermuehle mit geringem Energieeinsatz moeglich. Durch eine geeignete Sichtung muss diese jedoch noch weiter optimiert werden. Mit Multi-Fuel-Drallbrennern ist eine stickoxidarme Verbrennung moeglich. Der Brennstoff, der den groesseren Stickstoffeintrag in die Flamme bewirkt, soltle in die innere Rezirkulationszone eingeblasen werden. (orig)

Preparation and co-combustion of whole plants in a coal dust furnace; Aufbereitung und Mitverbrennung von Ganzpflanzen mit Steinkohle in einer Staubfeuerung

Energy Technology Data Exchange (ETDEWEB)

Siegle, V.; Spliethoff, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen (IVD)

1996-12-31

Co-combustion is a favourable and simple way of utilizing biomass. Owing to the high energy density of grains, whole plants must be ground very thoroughly for use in a coal dust furnace. This can be done with low energy consumption in a hammer mill. In addition, multifuel swirl burners permit selective supply of fuel and low-NO{sub x} combustion. The fuel with the highest nitrogen content should be blown into the inner recirculation zone. (orig) [Deutsch] Die Mitverbrennung von Biomasse ist eine guenstige und schnell zu realisierende Moeglichkeit, Biomasse in grossem Umfang zu nutzen. Um Ganzpflanzen in einer Staubfeuerung mitverbrennen zu koennen, muessen diese aufgrund der hohen Energiedichte der Koerner sehr fein aufgemahlen werden. Dies ist mit einer Hammermuehle mit geringem Energieeinsatz moeglich. Durch eine geeignete Sichtung muss diese jedoch noch weiter optimiert werden. Mit Multi-Fuel-Drallbrennern ist eine stickoxidarme Verbrennung moeglich. Der Brennstoff, der den groesseren Stickstoffeintrag in die Flamme bewirkt, soltle in die innere Rezirkulationszone eingeblasen werden. (orig)

The causes and consequences of blown-up coal dust

International Nuclear Information System (INIS)

Vrins, E.L.M.; Van Zuylen, E.J.

1991-11-01

The goal of the Dutch National Research Program Coal (NOK), which started in 1983, is to eliminate technical, economic and ecological objections, connected with the large-scale use of coal. The Blown-up Coal Dust program, which is completed in 1991, aimed at problems that arise, due to the dispersion of coal dust in the vicinity of coal storage and transshipment areas. The accumulated knowledge is categorized according to the route the dust itself follows, starting with activities that cause the dust and continuing up to the effects, of which nuisance in the neighborhood is the most important. The successive chapters are: Activities, Emission, Concentration, Deposition, Pollution and Nuisance and other effects. Inventories of available knowledge, models and measuring equipment have been carried out for each part. The models describe the connection between the various stages of the progress of the dust, from cause to consequence. Newly developed measuring equipment was tested in practice. Various analysis techniques were used and evaluated, such as gravimetric, chemical and optical analysis. A specific coal dust analysis technique is not available. 15 figs., 23 tabs., 1 appendix, 263 refs

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.

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.

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.

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

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.

Coal, energy of the future

International Nuclear Information System (INIS)

Lepetit, V.; Guezel, J.Ch.

2006-01-01

Coal is no longer considered as a 'has been' energy source. The production and demand of coal is growing up everywhere in the world because it has some strategic and technological advantages with respect to other energy sources: cheap, abundant, available everywhere over the world, in particular in countries with no geopolitical problems, and it is independent of supplying infrastructures (pipelines, terminals). Its main drawback is its polluting impact (dusts, nitrogen and sulfur oxides, mercury and CO 2 ). The challenge is to develop clean and high efficiency coal technologies like supercritical steam power plants or combined cycle coal gasification plants with a 50% efficiency, and CO 2 capture and sequestration techniques (post-combustion, oxy-combustion, chemical loop, integrated gasification gas combined cycle (pre-combustion)). Germany, who will abandon nuclear energy by 2021, is massively investing in the construction of high efficiency coal- and lignite-fired power plants with pollution control systems (denitrification and desulfurization processes, dust precipitators). (J.S.)

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

Mice housed on coal dust-contaminated sand: A model to evaluate the impacts of coal mining on health.

Science.gov (United States)

Caballero-Gallardo, Karina; Olivero-Verbel, Jesus

2016-03-01

Coal dust is the most important air pollutant in coal mining in regards to producing deleterious health effects. It permeates the surrounding environment threatening public health. The aim of this study was to evaluate the toxic effects associated with exposure to sand contaminated with coal dust particles below 38 μm in diameter, obtained from a mineral sample collected in the largest coal mine in South America, La Loma, Cesar, Colombia. Sterilized sand was spiked with coal dust to obtain concentrations ranging from zero to 4% coal dust. To model natural exposure, mice were housed for eight weeks in boxes containing this mixture as bedding after which, they were euthanized and blood and tissue samples were collected. Real time PCR analysis revealed an increase in Cyp1A1 mRNA for living on sand with coal dust concentrations greater than 2% compared to mice living on sand without coal dust. Unexpectedly, for mice on coal dust-polluted sand, Sod1, Scd1 and Nqo1 hepatic mRNA were downregulated. The Comet assay in peripheral blood cells and the micronucleus test in blood smears, showed a significant potential genotoxic effect only at the highest coal dust concentration. Histopathological analysis revealed vascular congestion and peribronchial inflammation in the lungs. A dose-response relationship for the presence of hepatic steatosis, vacuolization and nuclei enlargements was observed in the exposed animals. The data suggest living on a soil polluted with coal dust induces molecular, cellular and histopathological changes in mice. Accordingly, the proposed model can be used to identify deleterious effects of exposure to coal dust deposited in soils that may pose health risks for surrounding wildlife populations. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

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.

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.

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

Using proximate analysis to characterize airborne dust generation from bituminous coals

Energy Technology Data Exchange (ETDEWEB)

Page, S.J.; Organiscak, J.A.

2005-11-01

Prolonged exposure to airborne respirable coal dust is responsible for coal workers pneumoconiosis (CWP), commonly called black lung. Health research studies have identified that the prevalence and severity of CWP are directly related to both the amount of dust exposure and the coal rank. The amount of airborne respirable dust (ARD) smaller than 10 micrometers generated from breakage of different coals varies widely. To investigate the cause, researchers for the National Institute for Occupational Safety and Health (NIOSH) have conducted experiments to identify the causes of airborne respirable dust liberation. Laboratory crushing experiments were conducted on a range of low to high volatile bituminous coals from eight mines. The results indicate that the proximate analysis of a coal sample can provide a very good indicator of the potential for a dust problem. For application to the coal mining, processing, and utilization industries, data from 977 US coal seams compiled by the Department of Energy (DoE) has been used to calculate this dust generation potential from an equation based on the NIOSH measured data. A simple procedure for this calculation is provided. 1 fig.

Coal-peat compositions for co-combustion in local boilers

Directory of Open Access Journals (Sweden)

А. В. Михайлов

2016-08-01

Full Text Available In article results of experiments on creation of coal and peat fuel compositions for burning in solid-fuel boilers are described. The main objective of research consisted in development of combination of coal dust and natural peat without binding additives. The role of peat consists that it increases efficiency of process of granulation, being natural binding. The method of granulation allows to utilize waste of the coal industry. Joint burning of two types of fuel – coal dust and peat reduces emission of sulfur dioxides. The cost of peat raw materials is lower, than artificial binding, applied to briquetting of coal dust. The composition of mix of coal dust and peat varied in the ratio 2:1, 1:1 and 1:2 in volume ratio at humidity of mix before extrusion of 65 %. In the course of preparatory operations of coal raw materials its crushing and sifting through sieve of 24 mesh (0,707 mm was carried out. Procedure of hashing of samples of coal and peat was carried out before receiving homogeneous mixture. After hashing mix was located in piston press for receiving granules. Coal dust and wet peat pass semifixed extrusion on piston press with formation of cylindrical granules with a diameter of 16 mm. After extrusion of granule are dried to operational humidity of 25 %. Coal and peat fuel granules showed sufficient mechanical strength for transportation and power feed in solid-fuel boilers. Burning of coal and peat fuel granules in vitro at temperature of 800 °C does not lead to ashes agglomeration. The conducted preliminary researches showed prospects of utilization of coal waste by granulation method in mix with natural peat.

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

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.

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.

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.

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)

Coal Mine Dust Desquamative Chronic Interstitial Pneumonia: A Precursor of Dust-Related Diffuse Fibrosis and of Emphysema.

Science.gov (United States)

Jelic, Tomislav M; Estalilla, Oscar C; Sawyer-Kaplan, Phyllis R; Plata, Milton J; Powers, Jeremy T; Emmett, Mary; Kuenstner, John T

2017-07-01

Diseases associated with coal mine dust continue to affect coal miners. Elucidation of initial pathological changes as a precursor of coal dust-related diffuse fibrosis and emphysema, may have a role in treatment and prevention. To identify the precursor of dust-related diffuse fibrosis and emphysema. Birefringent silica/silicate particles were counted by standard microscope under polarized light in the alveolar macrophages and fibrous tissue in 25 consecutive autopsy cases of complicated coal worker's pneumoconiosis and in 21 patients with tobacco-related respiratory bronchiolitis. Coal miners had 331 birefringent particles/high power field while smokers had 4 (pcoal miner had intra-alveolar macrophages with silica/silicate particles and interstitial fibrosis ranging from minimal to extreme. All coal miners, including those who never smoked, had emphysema. Fibrotic septa of centrilobular emphysema contained numerous silica/silicate particles while only a few were present in adjacent normal lung tissue. In coal miners who smoked, tobacco-associated interstitial fibrosis was replaced by fibrosis caused by silica/silicate particles. The presence of silica/silicate particles and anthracotic pigment-laden macrophages inside the alveoli with various degrees of interstitial fibrosis indicated a new disease: coal mine dust desquamative chronic interstitial pneumonia, a precursor of both dust-related diffuse fibrosis and emphysema. In studied coal miners, fibrosis caused by smoking is insignificant in comparison with fibrosis caused by silica/silicate particles. Counting birefringent particles in the macrophages from bronchioalveolar lavage may help detect coal mine dust desquamative chronic interstitial pneumonia, and may initiate early therapy and preventive measures.

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.

Coal Mine Dust Desquamative Chronic Interstitial Pneumonia: A Precursor of Dust-Related Diffuse Fibrosis and of Emphysema

Directory of Open Access Journals (Sweden)

Tomislav M Jelic

2017-07-01

Full Text Available Background: Diseases associated with coal mine dust continue to affect coal miners. Elucidation of initial pathological changes as a precursor of coal dust-related diffuse fibrosis and emphysema, may have a role in treatment and prevention. Objective: To identify the precursor of dust-related diffuse fibrosis and emphysema. Methods: Birefringent silica/silicate particles were counted by standard microscope under polarized light in the alveolar macrophages and fibrous tissue in 25 consecutive autopsy cases of complicated coal worker's pneumoconiosis and in 21 patients with tobacco-related respiratory bronchiolitis. Results: Coal miners had 331 birefringent particles/high power field while smokers had 4 (p<0.001. Every coal miner had intra-alveolar macrophages with silica/silicate particles and interstitial fibrosis ranging from minimal to extreme. All coal miners, including those who never smoked, had emphysema. Fibrotic septa of centrilobular emphysema contained numerous silica/silicate particles while only a few were present in adjacent normal lung tissue. In coal miners who smoked, tobacco-associated interstitial fibrosis was replaced by fibrosis caused by silica/silicate particles. Conclusion: The presence of silica/silicate particles and anthracotic pigment-laden macrophages inside the alveoli with various degrees of interstitial fibrosis indicated a new disease: coal mine dust desquamative chronic interstitial pneumonia, a precursor of both dust-related diffuse fibrosis and emphysema. In studied coal miners, fibrosis caused by smoking is insignificant in comparison with fibrosis caused by silica/silicate particles. Counting birefringent particles in the macrophages from bronchioalveolar lavage may help detect coal mine dust desquamative chronic interstitial pneumonia, and may initiate early therapy and preventive measures.

Combustible dusts: a serious industrial hazard.

Science.gov (United States)

Joseph, Giby

2007-04-11

After investigating three fatal explosions in manufacturing plants, the U.S. Chemical Safety and Hazard Investigation Board (CSB) has concluded: The explosive hazard of combustible dust is not well known, and helping industry to understand this hazard is a priority. Prompted by these three incidents in North Carolina, Kentucky and Indiana and the need to increase the hazard awareness, CSB is conducting a study to examine the nature and scope of dust explosion risks in industry and to identify initiatives that may be necessary to more effectively prevent combustible dust fires and explosions. Such initiatives may include regulatory action, voluntary consensus standards, or other measures that could be taken by industry, labor, government, and other parties. A critical task of the dust study is analyzing past incidents to determine the severity of the problem within industry. The analysis is focusing on the number of incidents, injuries and fatalities, industrial sectors affected, and regulatory oversight. This paper presents the preliminary findings from CSBs analysis of combustible dust incidents over the past 25 years. This paper has not been approved by the Board and is published for general informational purposes only. Every effort has been made to accurately present the contents of any Board-approved report mentioned in this paper. Any material in the paper that did not originate in a Board-approved report is solely the responsibility of the authors and does not represent an official finding, conclusion, or position of the Board.

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.

Characterisation of metal combustion with DUST code

Energy Technology Data Exchange (ETDEWEB)

García-Cascales, José R., E-mail: jr.garcia@upct.es [DITF, ETSII, Universidad Politécnica de Cartagena, Dr Fleming s/n, 30202 Murcia (Spain); Velasco, F.J.S. [Centro Universitario de la Defensa de San Javier, MDE-UPCT, C/Coronel Lopez Peña s/n, 30730 Murcia (Spain); Otón-Martínez, Ramón A.; Espín-Tolosa, S. [DITF, ETSII, Universidad Politécnica de Cartagena, Dr Fleming s/n, 30202 Murcia (Spain); Bentaib, Ahmed; Meynet, Nicolas; Bleyer, Alexandre [Institut de Radioprotection et Sûreté Nucléaire, BP 17, 92260 Fontenay-aux-Roses (France)

2015-10-15

Highlights: • This paper is part of the work carried out by researchers of the Technical University of Cartagena, Spain and the Institute of Radioprotection and Nuclear Security of France. • We have developed a code for the study of mobilisation and combustion that we have called DUST by using CAST3M, a multipurpose software for studying many different problems of Mechanical Engineering. • In this paper, we present the model implemented in the code to characterise metal combustion which describes the combustion model, the kinetic reaction rates adopted and includes a first comparison between experimental data and calculated ones. • The results are quite promising although suggest that improvement must be made on the kinetic of the reaction taking place. - Abstract: The code DUST is a CFD code developed by the Technical University of Cartagena, Spain and the Institute of Radioprotection and Nuclear Security, France (IRSN) with the objective to assess the dust explosion hazard in the vacuum vessel of ITER. Thus, DUST code permits the analysis of dust spatial distribution, remobilisation and entrainment, explosion, and combustion. Some assumptions such as particle incompressibility and negligible effect of pressure on the solid phase make the model quite appealing from the mathematical point of view, as the systems of equations that characterise the behaviour of the solid and gaseous phases are decoupled. The objective of this work is to present the model implemented in the code to characterise metal combustion. In order to evaluate its ability analysing reactive mixtures of multicomponent gases and multicomponent solids, two combustion problems are studied, namely H{sub 2}/N{sub 2}/O{sub 2}/C and H{sub 2}/N{sub 2}/O{sub 2}/W mixtures. The system of equations considered and finite volume approach are briefly presented. The closure relationships used are commented and special attention is paid to the reaction rate correlations used in the model. The numerical

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

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.

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

Final report on dust monitoring near Kellingley coal mine, North Yorkshire

International Nuclear Information System (INIS)

Vallack, H.W.

1992-06-01

Dust deposition was monitored at a residential location near Kellingley Coal Mine over two four-weekly periods (November/December 1991 and March/April 1992) using a wet Frisbee dust deposit gauge. The mean rates of dust deposition for both periods (696.4 and 415.5 mg m -2 day -1 respectively) were well in excess of a proposed acceptable upper limit (195 mg m -2 day -1 ) for residential conditions. Mean estimated coal dust content during both periods (80.9 and 49.7 per cent) was also high. It is concluded that coal dust from Kellingley Coal Mine gave rise to excessively high levels of dust deposition at the monitoring site, especially during the first four-weekly period. The situation would appear to have deteriorated since a similar monitoring exercise was carried out in 1989. 4 refs, 2 figs, 2 tabs

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.

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

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)

Investigation of coal dust explosion hazard at the Nikola Tesla-A thermal power station

Energy Technology Data Exchange (ETDEWEB)

Golubovic, D

1987-10-01

Reports on investigations into coal dust explosion hazards in working places with high coal dust exposure, done in the Tesla-A thermal power station by Mining Institute of Belgrade specialists. Settled and floating coal dust concentrations were monitored for six months and samples analyzed for explosibility under lab conditions. Samples from transport and preparation facilities and the power station boiler house were taken. The entire plant was divided into 4 zones, depending on intensity of dust settlement and ventilation system. Coal dust generation varied from 0.3-65 g/min. Daily dust settlement ranged between 40 and 300 g/m/sup 2/. Total quantity of accumulated coal dust in the power plant ranged from 0.8-650 kg/day; 250 g/m/sup 3/ of coal dust may cause an explosion. Thus, a dangerous amount of coal dust, depending on work-site, will settle in 3.3.-21.8 days. Disturbance of settled dust may create explodable clouds. Details of measurements taken and data evaluation are included. 4 refs.

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.

Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport.

Science.gov (United States)

Shahan, M R; Seaman, C E; Beck, T W; Colinet, J F; Mischler, S E

2017-09-01

Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8.

Oxydative stress in rats caused by coal dust plus cigarette smoke

Directory of Open Access Journals (Sweden)

Nia Kania

2016-02-01

Full Text Available Coal dust and cigarette smoke are pollutants found in coal mines that are capable of inducing oxidative stress, the effects of which on blood malondialdehyde (MDA level and serum superoxide dismutase (SOD level are still unknown. The purpose of the present study was to evaluate the effect of coal dust and cigarette smoke on levels of MDA and SOD in rats. An experimental study was done on Wistar male rats divided into the following groups: control (C, coal dust exposure (14 days (CDE, cigarette smoke exposure (14 days (CSE, coal dust exposure (7 days followed by cigarette smoke exposure (7 days (CDE+CSE, cigarette smoke exposure (7 days followed by coal dust exposure (7 days (CSE+CDE. All exposures increased MDA levels and decreased SOD activity significantly between groups (p=0.000. All exposure groups had significantly increased blood MDA levels, compared to the control group, although there was no difference between CSE + CDE and CDE + CSE. For SOD levels, all exposure groups had significantly decreased the SOD levels compared to control. But there were no significant differences between CSE vs CDE and CDE + CSE vs CSE + CDE. We conclude that exposure to cigarette smoke significantly increases blood MDA level and decreases serum SOD activity, which was not found in exposure to coal dust. Combined exposures also increase blood MDA level and decrease serum SOD activity significantly.

Oxydative stress in rats caused by coal dust plus cigarette smoke

Directory of Open Access Journals (Sweden)

Nia Kania

2011-08-01

Full Text Available Coal dust and cigarette smoke are pollutants found in coal mines that are capable of inducing oxidative stress, the effects of which on blood malondialdehyde (MDA level and serum superoxide dismutase (SOD level are still unknown. The purpose of the present study was to evaluate the effect of coal dust and cigarette smoke on levels of MDA and SOD in rats. An experimental study was done on Wistar male rats divided into the following groups: control (C, coal dust exposure (14 days (CDE, cigarette smoke exposure (14 days (CSE, coal dust exposure (7 days followed by cigarette smoke exposure (7 days (CDE+CSE, cigarette smoke exposure (7 days followed by coal dust exposure (7 days (CSE+CDE. All exposures increased MDA levels and decreased SOD activity significantly between groups (p=0.000. All exposure groups had significantly increased blood MDA levels, compared to the control group, although there was no difference between CSE + CDE and CDE + CSE. For SOD levels, all exposure groups had significantly decreased the SOD levels compared to control. But there were no significant differences between CSE vs CDE and CDE + CSE vs CSE + CDE. We conclude that exposure to cigarette smoke significantly increases blood MDA level and decreases serum SOD activity, which was not found in exposure to coal dust. Combined exposures also increase blood MDA level and decrease serum SOD activity significantly.

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.

Assessment of respirable dust exposures in an opencast coal mine.

Science.gov (United States)

Onder, M; Yigit, E

2009-05-01

All major opencast mining activities produce dust. The major operations that produce dust are drilling, blasting, loading, unloading, and transporting. Dust not only deteriorates the environmental air quality in and around the mining site but also creates serious health hazards. Therefore, assessment of dust levels that arise from various opencast mining operations is required to prevent and minimize the health risks. To achieve this objective, an opencast coal mining area was selected to generate site-specific emission data and collect respirable dust measurement samples. The study covered various mining activities in different locations including overburden loading, stock yard, coal loading, drilling, and coal handling plant. The dust levels were examined to assess miners' exposure to respirable dust in each of the opencast mining areas from 1994 to 2005. The data obtained from the dust measurement studies were evaluated by using analysis of variance (ANOVA) and the Tukey-Kramer procedure. The analyses were performed by using Minitab 14 statistical software. It was concluded that, drilling operations produce higher dust concentration levels and thus, drill operators may have higher incidence of respiratory disorders related to exposure to dust in their work environment.

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.)

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.

Quantitative detection of settled coal dust over green canopy

Science.gov (United States)

Brook, Anna; Sahar, Nir

2017-04-01

The main task of environmental and geoscience applications are efficient and accurate quantitative classification of earth surfaces and spatial phenomena. In the past decade, there has been a significant interest in employing spectral unmixing in order to retrieve accurate quantitative information latent in in situ data. Recently, the ground-truth and laboratory measured spectral signatures promoted by advanced algorithms are proposed as a new path toward solving the unmixing problem in semi-supervised fashion. This study presents a practical implementation of field spectroscopy as a quantitative tool to detect settled coal dust over green canopy in free/open environment. Coal dust is a fine powdered form of coal, which is created by the crushing, grinding, and pulverizing of coal. Since the inelastic nature of coal, coal dust can be created during transportation, or by mechanically handling coal. Coal dust, categorized at silt-clay particle size, of particular concern due to heavy metals (lead, mercury, nickel, tin, cadmium, mercury, antimony, arsenic, isotopes of thorium and strontium) which are toxic also at low concentrations. This hazard exposes risk on both environment and public health. It has been identified by medical scientist around the world as causing a range of diseases and health problems, mainly heart and respiratory diseases like asthma and lung cancer. It is due to the fact that the fine invisible coal dust particles (less than 2.5 microns) long lodge in the lungs and are not naturally expelled, so long-term exposure increases the risk of health problems. Numerus studies reported that data to conduct study of geographic distribution of the very fine coal dust (smaller than PM 2.5) and related health impacts from coal exports, is not being collected. Sediment dust load in an indoor environment can be spectrally assessed using reflectance spectroscopy (Chudnovsky and Ben-Dor, 2009). Small amounts of particulate pollution that may carry a signature

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)

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.

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

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.

Dust characterisation for hot gas filters

Energy Technology Data Exchange (ETDEWEB)

Dockter, B.; Erickson, T.; Henderson, A.; Hurley, J.; Kuehnel, V.; Katrinak, K.; Nowok, J.; O`Keefe, C.; O`Leary, E.; Swanson, M.; Watne, T. [University of North Dakota, Grand Forks, ND (United States). Energy and Environmental Research Center (UNDEERC)

1998-03-01

Hot gas filtration to remove particulates from the gas flow upstream of the gas turbine is critical to the development of many of the advanced coal-fired power generation technologies such as the Air Blown Gasification Cycle (ABGC), a hybrid gasification combined cycle being developed in the UK. Ceramic candle filters are considered the most promising technology for this purpose. Problems of mechanical failure and of `difficult-to-clean` dusts causing high pressure losses across the filter elements need to be solved. The project investigated the behaviour of high-temperature filter dusts, and the factors determining the ease with which they can be removed from filters. The high-temperature behaviour of dusts from both combustion and gasification systems was investigated. Dust samples were obtained from full-scale demonstration and pilot-scale plant operating around the world. Dust samples were also produced from a variety of coals, and under several different operating conditions, on UNDEERC`s pilot-scale reactor. Key factors affecting dust behaviour were examined, including: the rates of tensile strength developing in dust cakes; the thermochemical equilibria pertaining under filtration conditions; dust adhesivity on representative filter materials; and the build-up and cleaning behaviour of dusts on representative filter candles. The results obtained confirmed the importance of dust temperature, dust cake porosity, cake liquid content, and particle size distribution in determining the strength of a dust cake. An algorithm was developed to indicate the likely sticking propensity of dusts as a function of coal and sorbent composition and combustion conditions. This algorithm was incorporated into a computer package which can be used to judge the degree of difficulty in filter cleaning that can be expected to arise in a real plant based on operating parameters and coal analyzes. 6 figs.

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.

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.

75 FR 3881 - Combustible Dust

Science.gov (United States)

2010-01-25

..., rubber, drugs, dried blood, dyes, certain textiles, and metals (such as aluminum and magnesium..., furniture manufacturing, metal processing, fabricated metal products and machinery manufacturing, pesticide... standard that will comprehensively address the fire and explosion hazards of combustible dust. The Agency...

75 FR 32142 - Combustible Dust

Science.gov (United States)

2010-06-07

.... Contact Mat Chibbaro, P.E., Fire Protection Engineer, Office of Safety Systems, OSHA Directorate of..., and metals (such as aluminum and magnesium). Industries that may have combustible dust hazards include..., chemical manufacturing, textile manufacturing, furniture manufacturing, metal processing, fabricated metal...

Accuracy criteria recommended for the certification of gravimetric coal-mine-dust samplers

International Nuclear Information System (INIS)

Bowman, J.D.; Bartley, D.L.; Breuer, G.M.; Doemeny, L.J.; Murdock, D.J.

1984-07-01

Procedures for testing bias and precision of gravimetric coal-mine-dust sampling units are reviewed. Performance criteria for NIOSH certification of personal coal-mine dust samplers are considered. The NIOSH criterion is an accuracy of 25% at the 95% confidence interval. Size distributions of coal-mine-dust are discussed. Methods for determining size distributions are described. Sampling and sizing methods are considered. Cyclone parameter estimation is discussed. Bias computations for general sampling units are noted. Recommended procedures for evaluating bias and precision of gravimetric coal mine dust personal samplers are given. The authors conclude that when cyclones are operated at lower rates, the NIOSH accuracy criteria can be met

Thermal coal utilization for the ESCAP region

Energy Technology Data Exchange (ETDEWEB)

1982-01-01

A selection of papers is presented originating from talks to coal utilization workshops for the ASEAN region in 1981. The papers cover: planning aspects - economic and technical aspects of coal usage, long term planning for fuel coal needs, planning and coal selection for coal-fired power plants, coal availability and marketing, and economic aspects of coal usage in developing countries; combustion and plant - changing from coal to oil, principles and problems of coal combustion, use of indigenous and imported coals and their effects on plant design, coal pulverizing mills, ash and dust disposal, environmental aspects of coal combustion, industrial sized coal-fired boilers; transport and storage -ocean shipment, coal receival facilities and associated operations, shipping and rail transport, coal handling and transport, environmental issue in the transport and handling of coal, coal preparation and blending; testing and properties - coal types, characterization properties and classification; training power plant operators; the cement industry and coal, the Australian black coal industry.

Hygienic evaluation of new technology for control of methane and dust in coal mines

Energy Technology Data Exchange (ETDEWEB)

Gadzhiev, G P; Deynega, V G; Sukhanov, V V; Levshina, I M; Yarym, N T; Petrenko, G A

1977-07-01

Exploitation of available new technology for mining is hindered by the dangers of gas evolution, and the need for maintenance of hygienic standards. The Moscow Mining Institute has developed, and proposed for industrial introduction, a new process for control of methane and dust in mine shafts; the method will help to raise significantly the productivity of excavating machines in high gas factor shafts. The process to combat methane and dust consists essentially in drilling boreholes from the side of the gallery, or from the outer surface, into the coal-bearing stratum. These boreholes are injected with a 24% solution of urea-formaldehyde resin (binder M/sub 2/), with 1% solution of ammonium chloride hardener. After several months this plastic is removed. The new technology involves the escape of toxic substances into the air, hence the need for hygienic testing. Additional study must estimate the danger of accidents, e.g., shaft fires, toxicity of combustion products of coal or binder. Study is also needed on pathologies which might occur to miners engaged in removal of the plastic with the new technology.

Investigations of co-combustion of plastics in a coal dust furnace; Untersuchungen zur Mitverbrennung von Kunststoffen in einer Kohlestaubfeuerung

Energy Technology Data Exchange (ETDEWEB)

Gerhardt, T; Spliethoff, H; Hein, K R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen (IVD); Christill, M; Kicherer, A; Seifert, H [BASF AG, Verfahrenstechnik-ZET/EH-L544, Ludwigshafen am Rhein (Germany)

1997-12-31

In a cooperation project of the Institute of Process Engineering and Power Plant TEchnology (IVD) at the University of Stuttgart and the BASF AG, investigations of co-combustion of plastic material in a coal dust furnace were carried out. The central question of the research work was the ignition and burnout of the particles in dependence of the residence time in the hot part of the furnace. Particle sizes were varied with the aim to define the largest possible particle size in order to minimize the cost of fuel preparation by grinding. On the other hand, tests were made with pure materials and synthetic mixtures of these in order to characterize the influence of different types of plastic. The investigations showed that plastics are suited as fuels for coal dust furnaces, and that the cost of fuel preparation can be reduced to an acceptable level. With polyethylene, which is difficult to ignite, an upper particle size limit of 1.25 to 1.5 mm was reached in the IVD test stand. In industrial applications with a different burner arrangement, even better results may be expected. (orig/AKB) [Deutsch] In einer Zusammenarbeit zwischen dem Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart und der BASF AG wurden Versuche zur Coverbrennung von Kunststoffen in einer Kohlenstaubfeuerung durchgefuehrt. Im Mittelpunkt der Untersuchungen standen Zuendung und Abbrand der Kunststoffpartikel in Abhaengigkeit von der Verweilzeit im heissen Bereich der Brennkanner. Variiert wurden hierzu zum einen die Partikelgroessen mit dem Ziel, den Aufbereitungsaufwand durch Zerkleinerung zu minimieren. Zur Charakterisierung der Einfluesse verschiedener Kunststoffarten wurden die Versuche mit unterschiedlichen Reinkunststoffen und synthetischen Mischungen durchgefuehrt. Die Versuche zeigen, dass sich Kunststoffe mit vertretbarem Mahlaufwand in der Staubfeuerung einsetzen lassen. Am Beispiel des Polyethylen, eines der thermogravimetrischen Analyse nach relativ

Investigations of co-combustion of plastics in a coal dust furnace; Untersuchungen zur Mitverbrennung von Kunststoffen in einer Kohlestaubfeuerung

Energy Technology Data Exchange (ETDEWEB)

Gerhardt, T.; Spliethoff, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen (IVD); Christill, M.; Kicherer, A.; Seifert, H. [BASF AG, Verfahrenstechnik-ZET/EH-L544, Ludwigshafen am Rhein (Germany)

1996-12-31

In a cooperation project of the Institute of Process Engineering and Power Plant TEchnology (IVD) at the University of Stuttgart and the BASF AG, investigations of co-combustion of plastic material in a coal dust furnace were carried out. The central question of the research work was the ignition and burnout of the particles in dependence of the residence time in the hot part of the furnace. Particle sizes were varied with the aim to define the largest possible particle size in order to minimize the cost of fuel preparation by grinding. On the other hand, tests were made with pure materials and synthetic mixtures of these in order to characterize the influence of different types of plastic. The investigations showed that plastics are suited as fuels for coal dust furnaces, and that the cost of fuel preparation can be reduced to an acceptable level. With polyethylene, which is difficult to ignite, an upper particle size limit of 1.25 to 1.5 mm was reached in the IVD test stand. In industrial applications with a different burner arrangement, even better results may be expected. (orig/AKB) [Deutsch] In einer Zusammenarbeit zwischen dem Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart und der BASF AG wurden Versuche zur Coverbrennung von Kunststoffen in einer Kohlenstaubfeuerung durchgefuehrt. Im Mittelpunkt der Untersuchungen standen Zuendung und Abbrand der Kunststoffpartikel in Abhaengigkeit von der Verweilzeit im heissen Bereich der Brennkanner. Variiert wurden hierzu zum einen die Partikelgroessen mit dem Ziel, den Aufbereitungsaufwand durch Zerkleinerung zu minimieren. Zur Charakterisierung der Einfluesse verschiedener Kunststoffarten wurden die Versuche mit unterschiedlichen Reinkunststoffen und synthetischen Mischungen durchgefuehrt. Die Versuche zeigen, dass sich Kunststoffe mit vertretbarem Mahlaufwand in der Staubfeuerung einsetzen lassen. Am Beispiel des Polyethylen, eines der thermogravimetrischen Analyse nach relativ

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

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.

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.

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...

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

Investigations into detonations of coal dust suspensions in oxygen-nitrogen

Energy Technology Data Exchange (ETDEWEB)

Edwards, D.; Fearnley, P.; Nettleton, M.

1987-03-01

The effect of particle size (practically monodispersed), volatile content and composition of gaseous oxygen-nitrogen mixtures on initiating flame acceleration rates in coal dust suspensions is investigated experimentally. Description is given of apparatus, material used and experiments carried out. The authors discusses: microwave interferograms, pressure oscillograms for various oxygen-nitrogen mixtures; development of ionization front speed in relation to distance from diaphragm; effect of composition on shock wave advance rates. It is concluded that: microwave interferometry can successfully be used in recording initiation of coal dust suspension detonations; ignition of confined coal dust suspensions by shock waves originated by detonation front in stoichiometric oxyacetylene mixtures can be explained by heating of coal particles in shock compression stream to ignition temperature (1000 K) by combined convection and radiation heat transfer. 16 refs.

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.

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.

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

78 FR 25308 - Proposed Collection; Comment Request; Coal Mine Dust Sampling Devices

Science.gov (United States)

2013-04-30

...; Coal Mine Dust Sampling Devices AGENCY: Mine Safety and Health Administration, Labor. ACTION: 60-Day... mines. CPDMs must be designed and constructed for coal miners to wear and operate without impeding their... related to Coal Mine Dust Sampling Devices. MSHA is particularly interested in comments that: Evaluate...

Source diagnostics of polycyclic aromatic hydrocarbons in urban road runoff, dust, rain and canopy throughfall.

Science.gov (United States)

Zhang, Wei; Zhang, Shucai; Wan, Chao; Yue, Dapan; Ye, Youbin; Wang, Xuejun

2008-06-01

Diagnostic ratios and multivariate analysis were utilized to apportion polycyclic aromatic hydrocarbon (PAH) sources for road runoff, road dust, rain and canopy throughfall based on samples collected in an urban area of Beijing, China. Three sampling sites representing vehicle lane, bicycle lane and branch road were selected. For road runoff and road dust, vehicular emission and coal combustion were identified as major sources, and the source contributions varied among the sampling sites. For rain, three principal components were apportioned representing coal/oil combustion (54%), vehicular emission (34%) and coking (12%). For canopy throughfall, vehicular emission (56%), coal combustion (30%) and oil combustion (14%) were identified as major sources. Overall, the PAH's source for road runoff mainly reflected that for road dust. Despite site-specific sources, the findings at the study area provided a general picture of PAHs sources for the road runoff system in urban area of Beijing.

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)

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)

Gastric cancer in coal miners: an hypothesis of coal mine dust causation

Energy Technology Data Exchange (ETDEWEB)

Ong, T M; Whong, W Z; Ames, R G

1983-10-01

An hypothesis is proposed to explain the elevated incidence of gastric cancer among coal miners. Inhaled coal mine dust, especially the larger particles, is cleared from the lung and tracheobronchial tree by mucociliary function, swallowed, and introduced into the stomach. Organic and/or inorganic materials in the dust can undergo intra-gastric nitrosation and/or interaction with exogenous chemicals to form carcinogenic compounds which in turn may lead to precancerous lesions, which may subsequently develop into gastric cancer. This sequence of events, however, depends upon occupational exposures as well as life-style features and individual genetic predisposition.

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.

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.

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.

Numerical research of reburning-process of burning of coal-dust torch

Science.gov (United States)

Trinchenko, Alexey; Paramonov, Aleksandr; Kadyrov, Marsel; Koryabkin, Aleksey

2017-10-01

This work is dedicated to numerical research of ecological indicators of technological method of decrease in emissions of nitrogen oxides at combustion of solid fuel in coal-dust torch to improve the energy efficiency of steam boilers. The technology of step burning with additional input in zone of the maximum concentration of pollutant of strongly crushed fuel for formation of molecular nitrogen on surface of the burning carbon particles is considered. Results of modeling and numerical researches of technology, their analysis and comparison with the experimental data of the reconstructed boiler are given. Results of work show that input of secondary fuel allows to reduce emissions of nitrogen oxides by boiler installation without prejudice to its economic indicators.

Source diagnostics of polycyclic aromatic hydrocarbons in urban road runoff, dust, rain and canopy throughfall

International Nuclear Information System (INIS)

Zhang Wei; Zhang Shucai; Wan Chao; Yue Dapan; Ye Youbin; Wang Xuejun

2008-01-01

Diagnostic ratios and multivariate analysis were utilized to apportion polycyclic aromatic hydrocarbon (PAH) sources for road runoff, road dust, rain and canopy throughfall based on samples collected in an urban area of Beijing, China. Three sampling sites representing vehicle lane, bicycle lane and branch road were selected. For road runoff and road dust, vehicular emission and coal combustion were identified as major sources, and the source contributions varied among the sampling sites. For rain, three principal components were apportioned representing coal/oil combustion (54%), vehicular emission (34%) and coking (12%). For canopy throughfall, vehicular emission (56%), coal combustion (30%) and oil combustion (14%) were identified as major sources. Overall, the PAH's source for road runoff mainly reflected that for road dust. Despite site-specific sources, the findings at the study area provided a general picture of PAHs sources for the road runoff system in urban area of Beijing. - Urban road runoff and road dust, canopy throughfall and rain were considered as a system for diagnostics of PAH sources

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.

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

Safety analysis of the 700-horsepower combustion test facility

Energy Technology Data Exchange (ETDEWEB)

Berkey, B.D.

1981-05-01

The objective of the program reported herein was to provide a Safety Analysis of the 700 h.p. Combustion Test Facility located in Building 93 at the Pittsburgh Energy Technology Center. Extensive safety related measures have been incorporated into the design, construction, and operation of the Combustion Test Facility. These include: nitrogen addition to the coal storage bin, slurry hopper, roller mill and pulverizer baghouse, use of low oxygen content combustion gas for coal conveying, an oxygen analyzer for the combustion gas, insulation on hot surfaces, proper classification of electrical equipment, process monitoring instrumentation and a planned remote television monitoring system. Analysis of the system considering these factors has resulted in the determination of overall probabilities of occurrence of hazards as shown in Table I. Implementation of the recommendations in this report will reduce these probabilities as indicated. The identified hazards include coal dust ignition by hot ductwork and equipment, loss of inerting within the coal conveying system leading to a coal dust fire, and ignition of hydrocarbon vapors or spilled oil, or slurry. The possibility of self-heating of coal was investigated. Implementation of the recommendations in this report will reduce the ignition probability to no more than 1 x 10/sup -6/ per event. In addition to fire and explosion hazards, there are potential exposures to materials which have been identified as hazardous to personal health, such as carbon monoxide, coal dust, hydrocarbon vapors, and oxygen deficient atmosphere, but past monitoring experience has not revealed any problem areas. The major environmental hazard is an oil spill. The facility has a comprehensive spill control plan.

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.

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

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.

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.

Lead in Chinese villager house dust: Geographical variation and influencing factors

International Nuclear Information System (INIS)

Bi, Xiangyang; Liu, Jinling; Han, Zhixuan; Yang, Wenlin

2015-01-01

House dust has been recognized as an important contributor to Pb exposure of children. Here we conducted a comprehensive study to investigate geographical variation of Pb in Chinese villager house dust. The influences of outdoor soil Pb concentrations, dates of construction, house decoration materials, heating types, and site specific pollution on Pb concentrations in house dust were evaluated. The concentrations of Pb in 477 house dust samples collected from twenty eight areas throughout China varied from 12 to 2510 mg/kg, with a median concentration of 42 mg/kg. The median Pb concentrations in different geographical areas ranged from 16 (Zhangjiakou, Hebei) to 195 mg/kg (Loudi, Hunan). No correlations were found between the house dust Pb concentrations and the age of houses, as well as house decoration materials. Whereas outdoor soil, coal combustion, and site specific pollution may be potential Pb sources. Principal component analysis (PCA) confirmed that elemental compositions of the house dust were controlled by both anthropogenic and geogenic sources. Using scanning electron microscopy (SEM), the Pb bearing particles in the house dust were also studied. - Highlights: • Geographical variation in house dust Pb concentrations were observed. • Dust Pb concentrations were not associated with house age and decoration materials. • Soil, coal combustion, and site specific pollution were potential Pb sources. • Pb bearing particles were identified by SEM-EDX. - The variations of Pb in Chinese villager house dust were controlled by outdoor soil, coal combustion, and site specific pollution sources.

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.

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.

Assessment of nitrogen oxide emission for designing boilers fired with coal dust

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.; Gusev, L.N.; Babii, V.I.

1983-09-01

A method for forecasting emission of nitrogen oxides from steam boilers fired with coal is described. The method produces accurate results when nitrogen oxide emission from furnaces with straight-flow burners and turbulent-type burners fired with coal dusts is forecast. Oxides formed by decomposition of chemical compounds in coal (so-called 'fuel' nitrogen oxides) and nitrogen oxides formed by oxidation of molecular nitrogen by atomic oxygen (so-called 'thermal' nitrogen oxides) are evaluated. Zones in which the two types of nitrogen oxide are formed in flames are characterized. Factors which influence formation of nitrogen oxides in a furnace are evaluated: excess air, flue gas recirculation, design of a furnace and burners, movement of air and coal dust mixture in a furnace, temperature, methods for coal dust preparation, coal dust properties. Equations for forecasting emission of nitrogen oxides from furnaces are derived. Nomograms for easy calculation of emission are also given. Examples of using the method for forecasting emission of nitrogen oxides from furnaces fired with coal from the Kuzbass, the Donbass and Ehkibastuz are discussed. Comparisons of emission of nitrogen oxides calculated on the basis of the method and emission determined experimentally show that forecasting accuracy is high and errors do not exceed 10%. 5 references.

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.

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.

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.

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.

Co-combustion of Fossil Fuels and Waste

DEFF Research Database (Denmark)

Wu, Hao

The Ph.D. thesis deals with the alternative and high efficiency methods of using waste-derived fuels in heat and power production. The focus is on the following subjects: 1) co-combustion of coal and solid recovered fuel (SRF) under pulverized fuel combustion conditions; 2) dust-firing of straw...

Respirable quartz hazard associated with coal mine roof bolter dust

International Nuclear Information System (INIS)

Joy, G.J.; Beck, T.W.; Listak, J.M.

2010-01-01

Pneumoconiosis has been reported to be increasing among underground coal miners in the Southern Appalachian Region. The National Institute for Occupational Safety and Health conducted a study to examine the particle size distribution and quartz content of dust generated by the installation of roof bolts in mines. Forty-six bulk samples of roof bolting machine pre-cleaner cyclone dump dust and collector box dust were collected from 26 underground coal mines. Real-time and integrated airborne respirable dust concentrations were measured on 3 mining sections in 2 mines. The real-time airborne dust concentrations profiles were examined to identify any concentration changes that might be associated with pre-cleaner cyclone dust discharge events. The study showed that bolter dust is a potential inhalation hazard due to the fraction of dust less than 10 μm in size, and the quartz content of the dust. The pre-cleaner cyclone dust was significantly larger than the collector box dust, indicating that the pre-cleaner functioned properly in removing the larger dust size fraction from the airstream. However, the pre-cleaner dust still contained a substantial amount of respirable dust. It was concluded that in order to maintain the effectiveness of a roof bolter dust collector, periodic removal of dust is required. Appropriate work procedures and equipment are necessary to minimize exposure during this cleaning task. 13 refs., 3 tabs., 2 figs.

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).

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)

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.

78 FR 79010 - Criteria to Certify Coal Mine Rescue Teams

Science.gov (United States)

2013-12-27

... coal requires more heat to combust; (3) anthracite dust does not propagate an explosion; and (4) there... to Certify Coal Mine Rescue Teams AGENCY: Mine Safety and Health Administration, Labor. ACTION... updated the coal mine rescue team certification criteria. The Mine Improvement and New Emergency Response...

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.

Contributions of dust exposure and cigarette smoking to emphysema severity in coal miners in the United States

Energy Technology Data Exchange (ETDEWEB)

Kuempel, E.D.; Wheeler, M.W.; Smith, R.J.; Vallyathan, V.; Green, F.H.Y. [NIOSH, Cincinnati, OH (United States)

2009-08-15

Previous studies have shown associations between dust exposure or lung burden and emphysema in coal miners, although the separate contributions of various predictors have not been clearly demonstrated. The objective was to quantitatively evaluate the relationship between cumulative exposure to respirable coal mine dust, cigarette smoking, and other factors on emphysema severity. The study group included 722 autopsied coal miners and nonminers in the United States. Data on work history, smoking, race, and age at death were obtained from medical records and questionnaire completed by next-of-kin. Emphysema was classified and graded using a standardized schema. Job-specific mean concentrations of respirable coal mine dust were matched with work histories to estimate cumulative exposure. Relationships between various metrics of dust exposure (including cumulative exposure and lung dust burden) and emphysema severity were investigated in weighted least squares regression models. Emphysema severity was significantly elevated in coal miners compared with nonminers among ever- and never-smokers (P < 0.0001). Cumulative exposure to respirable coal mine dust or coal dust retained in the lungs were significant predictors of emphysema severity (P < 0.0001) after accounting for cigarette smoking, age at death, and race. The contributions of coal mine dust exposure and cigarette smoking were similar in predicting emphysema severity averaged over this cohort. Coal dust exposure, cigarette smoking, age, and race are significant and additive predictors of emphysema severity in this study.

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.

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

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.

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.

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.

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...

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.

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)

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...

Coal dust contiguity-induced changes in the concentration of TNF- and NF- B p65 on the ocular surface

Energy Technology Data Exchange (ETDEWEB)

Sun, Z.Y.; Hong, J.; Liu, Z.Y.; Jin, X.D.; Gu, C.H. [China Medical University, Shenyang (China)

2009-07-01

To observe the influence of coal dust on ocular surface of coal miners and rabbits with coal dust contiguity on expression TNF- and NF- Bp65 and dry eye occurrence. Expression TNF- and NF- Bp65 in ocular surface were determined. Results showed tear production, BUT and lysozyme decreased for coal miners and rabbits with coal dust contiguity. Coal dust exposure was linked to development of xerophthalmia, and induced a higher expression of NF- B p65 and TNF- perhaps as a mechanism to resist coal dust ocular surface injury.

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.

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.

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...

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.

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

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.

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.

[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.

The evaluation and quantification of respirable coal and silica dust concentrations: a task-based approach.

Science.gov (United States)

Grové, T; Van Dyk, T; Franken, A; Du Plessis, J

2014-01-01

Silicosis and coal worker's pneumoconiosis are serious occupational respiratory diseases associated with the coal mining industry and the inhalation of respirable dusts containing crystalline silica. The purpose of this study (funded by the Mine Health and Safety Council of South Africa) was to evaluate the individual contributions of underground coal mining tasks to the respirable dust and respirable silica dust concentrations in an underground section by sampling the respirable dust concentrations at the intake and return of each task. The identified tasks were continuous miner (CM) cutting, construction, transfer of coal, tipping, and roof bolting. The respirable dust-generating hierarchy of the tasks from highest to lowest was: transfer of coal > CM right cutting > CM left cutting > CM face cutting > construction > roof bolting > tipping; and for respirable silica dust: CM left cutting > construction > transfer of coal > CM right cutting. Personal exposure levels were determined by sampling the exposures of workers performing tasks in the section. Respirable dust concentrations and low concentrations of respirable silica dust were found at the intake air side of the section, indicating that air entering the section is already contaminated. The hierarchy for personal respirable dust exposures was as follows, from highest to lowest: CM operator > cable handler > miner > roof bolt operator > shuttle car operator, and for respirable silica dust: shuttle car operator > CM operator > cable handler > roof bolt operator > miner. Dust control methods to lower exposures should include revision of the position of workers with regard to the task performed, positioning of the tasks with regard to the CM cutting, and proper use of the line curtains to direct ventilation appropriately. The correct use of respiratory protection should also be encouraged.

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

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...

30 CFR 74.5 - Tests of coal mine dust personal sampler units.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of coal mine dust personal sampler units... Personal Sampler Unit § 74.5 Tests of coal mine dust personal sampler units. (a) The National Institute for... tests and evaluations to determine whether the pump unit of a CMDPSU that is submitted for approval...

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.)

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.

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.

Dust collection capacity of plants growing in coal mining areas

International Nuclear Information System (INIS)

Maiti, S.K.

1993-01-01

Plant can act as living filter of dust pollution in coal mining areas, where the amount of suspended particulate matter and dust fall rate is very high. Therefore, plant species growing in coal mining areas are classified as evergreen or deciduous with simple and compound leaf basis. The dust arresting capacity of each leaf is measured and expressed in g/m 2 . The study indicated that evergreen plants with simple, pilose surface, like - Alstonia, Ficus cunea, F. benghalensis and Mangifera indica are good dust catcher than evergreen compound leaves of Cassia siamea, Acacia arabica and Leucaena leucocephala. Deciduous with simple leaves, such as Zizyphus mauritiana, F. religiosa, Psidium guyava are also good dust collectors. Suitable plant species also help in quick reclamation of mined out areas; one practical difficulty for establishment of trees as green belts or reclamation purpose, has been incidence of cattle grazing. This study suggested a systematic way of selecting plant species on the basis of their efficiency in dust control and resistance to cattle grazing. (author). 16 refs., 3 tabs

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.

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.

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.

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.

Increasing the dust separation efficiency by water spray during the operation of coal combines

Energy Technology Data Exchange (ETDEWEB)

Feskov, M I; Kurdyukov, A N

1974-08-01

Possibilities of efficient wet dust separation around coal combines and their working members are described. The water consumption for dust separation around working members ranges from 0.3 to 1 l/cu m dust-laden air. The working member can be isolated from his surroundings by plastic walls or shields, while water or air curtains are rather unreliable. Such isolation requires a considerable increase in the water expenditure to improve the wettability of the coal particles by humidifying the air. Laboratory experiments revealed improved wettability and sedimentability of coal particles in humid air.

Biological action of coal dust formed during excavation of seams after physicochemical treatment

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, V V; Gadzhiev, G P

1982-03-01

Destruction of the self-cleansing function of lungs by dust is important in the development of pneumoconiosis. It is expedient to study the influence of chemical substances, injected into coal seams to prevent methane bursts and reduce dust formation, on the physiologic mechanisms for the protection of the lungs from dust (macrophageal reaction of lungs, function of mucociliary transport). An investigation using 15, 24 and 50% solutions of binder KM/SUB/2 modified by polyvinyl alcohol, and 3% hydrochloric acid solution was conducted on 200 white rats. Reaction of rats treated with solutions of binder in different concentrations proved that accumulation of dust in lungs and lymph nodes was directly related to the strength of the solution. Three percent hydrochloric acid solution diminished dust accumulation in paratracheal lymph nodes and content of lipids and collagen in the lungs. Inhalation of dust treated with a 50% solution of binder KM/SUB/2 increases the deposit of dust in the lungs and increases fiber production. Therefore, solutions of more than 24% binder should not be used to treat coal. Solutions of 15% and 24% do not significantly affect the process of dust accumulation in the lungs. A 3% solution of hydrochloric acid reduces the dust-forming capacity of the coal mass. (13 refs.) (In Russian)

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...

Risk of dust explosions of combustible nanomaterials

International Nuclear Information System (INIS)

Dobashi, Ritsu

2009-01-01

Nanomaterials have several valuable properties and are widely used for various practical applications. However, safety matters are suspected such as the influence on health and environment, and fire and explosion hazards. To minimize the risk of nanomaterials, appropriate understanding of these hazards is indispensable. Nanoparticles of combustible materials have potential hazard of dust explosion accidents. However, the explosion risk of nanomaterials has not yet been understood adequately because of the lack of data for nanomaterials. In this presentation, the risk of dust explosions of nanomaterials is discussed.

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.

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...

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.

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.

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

75 FR 64411 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

Science.gov (United States)

2010-10-19

... industries, such as mining, by reducing workplace deaths and improving the health of coal miners. This..., enhanced enforcement, collaborative outreach, and education and training. The initiative will reduce, and... reducing the respirable coal mine dust levels, miners continue to develop black lung. Based on recent data...

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

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.

The effects of coal dust on photosynthetic performance of the mangrove, Avicennia marina in Richards Bay, South Africa

International Nuclear Information System (INIS)

Naidoo, G.; Chirkoot, D.

2004-01-01

Richards Bay, on the northern KwaZulu-Natal coast, is the largest coal exporting port in South Africa. The coal is stored at the Richards Bay Coal Terminal (RBCT) prior to export. Dust from coal operations is a major problem in the Richards Bay area. In this study, we tested the hypothesis that coal dust adversely affects photosynthetic performance of Avicennia marina (Forssk.) Vierh., the dominant mangrove species in the harbour. Photosynthetic performance was determined on 10 trees by measuring carbon dioxide uptake and chlorophyll fluorescence parameters at two elevation sites and on upper and lower leaf surfaces that were covered or uncovered with coal dust. Measurements were made on five clear, sunny days at saturating light (>1000 μmol m -2 s -1 ) and high temperature (28-30 deg. C). Coal dust significantly reduced carbon dioxide exchange of upper and lower leaf surfaces by 17-39%, the reduction being generally greater on the lower leaf surface that is covered by a dense mat of trichomes and salt glands. The reduction in carbon dioxide exchange by coal dust was higher at the high elevation site that supported isolated dwarfed trees. The chlorophyll fluorescence data indicated that leaves coated with dust exhibited significantly lower photosystem II (PS II) quantum yield, lower electron transport rate (ETR) through PSII and reduced quantum efficiency of PSII (F v F m ). The chlorophyll fluorescence data supported the gas exchange measurements and are consistent with reduced photosynthetic performance of leaves coated with coal dust. - Coal dust reduced photosynthetic performance of the mangrove, Avicennia marina

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.

77 FR 38323 - Proposed Extension of Existing Information Collection; Respirable Coal Mine Dust Sampling

Science.gov (United States)

2012-06-27

... Information Collection; Respirable Coal Mine Dust Sampling AGENCY: Mine Safety and Health Administration... Sampling'' to more accurately reflect the type of information that is collected. Chronic exposure to... dust levels since 1970 and, consequently, the prevalence rate of black lung among coal miners, severe...

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

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

Experimental Investigation of Coal Dust Wettability Based on Surface Contact Angle

Directory of Open Access Journals (Sweden)

Gang Zhou

2016-01-01

Full Text Available Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.

From explosions to black lung: a history of efforts to control coal mine dust.

Science.gov (United States)

Weeks, J L

1993-01-01

Highlights in the history of efforts to prevent occupational lung disease among coal miners in the United States are reviewed. The Federal Coal Mine Health and Safety Act of 1969 is summarized, and the sources and effects of its provisions to prevent coal workers' pneumoconiosis are examined. Descriptions follow of the identification of coal workers' pneumoconiosis as a disease, identification of respirable coal mine dust as its cause, and establishment and enforcement of an exposure limit. The development of prevention efforts focusing on surveillance of both exposure and outcome and of enforcement of dust control methods is examined.

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.

Phytotoxicity assessment of a methanolic coal dust extract in Lemna minor.

Science.gov (United States)

Coronado-Posada, Nadia; Cabarcas-Montalvo, Maria; Olivero-Verbel, Jesus

2013-09-01

Coal mining generates negative effects on environment, human health, hydrodynamics of mining areas and biodiversity. However, the impacts of this activity are less known in plants. Lemna minor is one of the most commonly used plants in aquatic toxicity tests due to its ubiquitous distribution in ponds and lakes, culture conditions and the free-floating habitat that exposes it to hydrophobic as well as dissolved compounds. The goal of this research was to evaluate the effects of a methanolic coal dust extract on L. minor. Macrophytes were exposed to six different concentrations of coal extract (from 7.81 to 250 mg/L) for 5 days, following the OECD test guideline 221. The coal extract had a half inhibitory concentration (IC50) of 99.66 (184.95-54.59) mg/L for the number of fronds. Several signs of toxicity such as chlorosis, reduction in the size of the fronds, abscission of fronds and roots, and the presence of necrotic tissues were observed at concentrations lower than the IC50. Preliminary Gas Chromatography-Mass Spectrometry analysis of the coal dust extract revealed the presence of several compounds, including, among others, alkanes, carboxylic acids and polycyclic aromatic hydrocarbons (PAHs), these lasts, may be responsible for some of the observed effects. These results demonstrated that coal dust has phytotoxic effects and should not be considered as an inert material. Copyright © 2013 Elsevier Inc. All rights reserved.

Research into properties of dust from domestic central heating boiler fired with coal and solid biofuels

Directory of Open Access Journals (Sweden)

Konieczyński Jan

2017-06-01

Full Text Available The aim of this research was to assess the content and composition of the pollutants emitted by domestic central heating boilers equipped with an automatic underfeed fuel delivery system for the combustion chamber. The comparative research was conducted. It concerned fuel properties, flue gas parameters, contents of dust (fl y ash and gaseous substances polluting the air in the flue gases emitted from a domestic CH boiler burning bituminous coal, pellets from coniferous wood, cereal straw, miscanthus, and sunflower husks, coniferous tree bark, and oats and barley grain. The emission factors for dust and gaseous air pollutants were established as they are helpful to assess the contribution of such boilers in the atmospheric air pollution. When assessing the researched boiler, it was found out that despite the development in design and construction, flue gases contained fly ash with a significant EC content, which affected the air quality.

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.

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.

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

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.

A Standard Characterization Methodology for Respirable Coal Mine Dust Using SEM-EDX

Directory of Open Access Journals (Sweden)

Rachel Sellaro

2015-12-01

Full Text Available A key consideration for responsible development of mineral and energy resources is the well-being of workers. Respirable dust in mining environments represents a serious concern for occupational health. In particular, coal miners can be exposed to a variety of dust characteristics depending on their work activities, and some exposures may pose risk for lung diseases like CWP and silicosis. As underscored by common regulatory frameworks, respirable dust exposures are generally characterized on the basis of total mass concentration, and also the silica mass fraction. However, relatively little emphasis has been placed on other dust characteristics that may be important in terms of identifying health risks. Comprehensive particle-level analysis to estimate chemistry, size, and shape distributions of particles is possible. This paper describes a standard methodology for characterization of respirable coal mine dust using scanning electron microscopy (SEM with energy dispersive X-ray (EDX. Preliminary verification of the method is shown based several dust samples collected from an underground mine in Central Appalachia.

Combustion means for solid fuels

Energy Technology Data Exchange (ETDEWEB)

Murase, D.

1987-09-23

A combustion device for solid fuel, suitable for coal, coke, charcoal, coal-dust briquettes etc., comprising:- a base stand with an opening therein, an imperforate heat resistant holding board locatable to close said opening; a combustion chamber standing on the base stand with the holding board forming the base of the combustion chamber; a wiper arm pivoted for horizontal wiping movement over the upper surface of the holding board; an inlet means at a lower edge of said chamber above the base stand, and/or in a surrounding wall of said chamber, whereby combustion air may enter as exhaust gases leave the combustion chamber; an exhaust pipe for the exhaust gases; generally tubular gas-flow heat-exchange ducting putting the combustion chamber and exhaust pipe into communication; and means capable of moving the holding board into and out of the opening for removal of ash or other residue. The invention can be used for a heating system in a house or in a greenhouse or for a boiler.

Continuous dust monitoring in headings in underground coal mines

Directory of Open Access Journals (Sweden)

Kazimierz Lebecki

2016-01-01

Full Text Available The article presents hazardous conditions of airborne dust based on the results of measurements of dust concentration taken at work-places at a underground rock-coal face drilled by a heading machine with combined ventilation (suction and forced ventilation with dust collector. The measurements were taken using three methods in order to examine and assess the actual conditions within the excavation subject to the study. The measurement results and conclusions show major difficulties in achieving MAC levels. Research conclusions indicate the low efficiency of collective and personal measures applied to protect against dust harmful to health as well as the need to improve them.

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.

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.

Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

Science.gov (United States)

Patts, Justin R; Barone, Teresa L

2017-05-01

Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may

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.

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

Open-air sprays for capturing and controlling airborne float coal dust on longwall faces

Science.gov (United States)

Beck, T.W.; Seaman, C.E.; Shahan, M.R.; Mischler, S.E.

2018-01-01

Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce the risk of coal-dust-fueled explosions. The goal of this U.S. National Institute for Occupational Safety and Health study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust, smaller than 75 µm in diameter, in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity of 3.6 m/s (700 fpm). Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle should be operated at high fluid pressures to produce smaller droplets and move more air. These findings agree with past respirable dust control research, providing guidance on spray selection and spray array design in ongoing efforts to control airborne float dust over the entire longwall ventilated opening. PMID:29348700

Open-air sprays for capturing and controlling airborne float coal dust on longwall faces.

Science.gov (United States)

Beck, T W; Seaman, C E; Shahan, M R; Mischler, S E

2018-01-01

Float dust deposits in coal mine return airways pose a risk in the event of a methane ignition. Controlling airborne dust prior to deposition in the return would make current rock dusting practices more effective and reduce the risk of coal-dust-fueled explosions. The goal of this U.S. National Institute for Occupational Safety and Health study is to determine the potential of open-air water sprays to reduce concentrations of airborne float coal dust, smaller than 75 µm in diameter, in longwall face airstreams. This study evaluated unconfined water sprays in a featureless tunnel ventilated at a typical longwall face velocity of 3.6 m/s (700 fpm). Experiments were conducted for two nozzle orientations and two water pressures for hollow cone, full cone, flat fan, air atomizing and hydraulic atomizing spray nozzles. Gravimetric samples show that airborne float dust removal efficiencies averaged 19.6 percent for all sprays under all conditions. The results indicate that the preferred spray nozzle should be operated at high fluid pressures to produce smaller droplets and move more air. These findings agree with past respirable dust control research, providing guidance on spray selection and spray array design in ongoing efforts to control airborne float dust over the entire longwall ventilated opening.

The theory and technology of enclosure dust-laying model in speeded advance of coal road

Energy Technology Data Exchange (ETDEWEB)

Wei-Min Cheng; Xiang-Sheng Liu; Guo-Qiang Ruan; Yun-Xiang Guo; Gang Wang [Shandong University of Science and Technology, Qingdao (China). Key Laboratory of Mine Disaster Prevention and Control

2009-02-15

In order to solve the problem of high dust concentration caused by the rapid advance of coal roadways using the ABM20 development machine, a method suitable for the rapid advance of coal roadways in China was proposed. By using the mathematic model method to contrast the wind current field and dust field of the drivage face under different drivage velocities, an optimized drivage velocity of the fully-mechanized development machine was obtained. The theories were tested in an industry experiment. Analysis of the data indicates that the proposed enclosure dust-laying system can significantly lower the dust concentration at the heading face. It also has some advantages in accomplishing the effective advance of coal mines. 9 refs., 5 figs.

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.

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.

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.

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

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.

Effect of catalysts on heterogeneous oxidation of coal

Energy Technology Data Exchange (ETDEWEB)

Glazkova, A P; Kazarova, Yu A; Suslov, A V

1978-01-01

Analyzes the effects of catalysts on the heterogeneous oxidation of coal in deflagration processes of stoichiometric mixtures. The following substances are studied as catalysts: alkali and alkaline-earth metals, and compounds of copper, lead, chromium, iron, and sulfur. In the first case the catalysts are used in the form of nitrates and the nitrate simultaneously plays the role of an oxidizer. In the second case the catalysts are added to stoichiometric mixtures of ammonium nitrate with carbon. It is shown that during carbon oxidation by nitrates the catalytic efficiency of the metals studied forms the following order: sodium > lead > potassium > barium > aluminium > calcium > magnesium > copper. The calculated and experimental parameters of combustion are given. The problem of dependence of combustion rate on combustion heat, the mechanism of the combustion reaction and the catalytic effects of the additives are discussed. Features of heterogeneous catalysis in the oxidation process of carbon by various oxidizers are analyzed. The investigations on the combustion process are important as the process takes place during explosion of coal dust in underground coal mines and during burning of coal in industrial furnaces. (34 refs.) (In Russian)

Health impacts of coal and coal use: Possible solutions

Science.gov (United States)

Finkelman, R.B.; Orem, W.; Castranova, V.; Tatu, C.A.; Belkin, H.E.; Zheng, B.; Lerch, H.E.; Maharaj, S.V.; Bates, A.L.

2002-01-01

Coal will be a dominant energy source in both developed and developing countries for at least the first half of the 21st century. Environmental problems associated with coal, before mining, during mining, in storage, during combustion, and postcombustion waste products are well known and are being addressed by ongoing research. The connection between potential environmental problems with human health is a fairly new field and requires the cooperation of both the geoscience and medical disciplines. Three research programs that illustrate this collaboration are described and used to present a range of human health problems that are potentially caused by coal. Domestic combustion of coal in China has, in some cases, severely affected human health. Both on a local and regional scale, human health has been adversely affected by coals containing arsenic, fluorine, selenium, and possibly, mercury. Balkan endemic nephropathy (BEN), an irreversible kidney disease of unknown origin, has been related to the proximity of Pliocene lignite deposits. The working hypothesis is that groundwater is leaching toxic organic compounds as it passes through the lignites and that these organics are then ingested by the local population contributing to this health problem. Human disease associated with coal mining mainly results from inhalation of particulate matter during the mining process. The disease is Coal Worker's Pneumoconiosis characterized by coal dust-induced lesions in the gas exchange regions of the lung; the coal worker's "black lung disease". ?? 2002 Elsevier Science B.V. All rights reserved.

Disposal of coal and hematite dusts inhaled successively

Energy Technology Data Exchange (ETDEWEB)

Heppleston, A G

1958-01-01

Rabbits and rats were exposed in a chamber to coal (20,000 and 10,000 particles/ml) and hematite (20,000 and 37,000 particles/ml) in succession to follow deposition and clearance by color. Exposures were 5 days/wk, 20 hr/day. Generally, there was dust widely but not uniformly distributed in peripheral alveoli, tending to aggregate and clump in more proximal alveoli with time. There was initial nonuniform distribution more uniform with exposure time. Aggregation mostly through phagocyte activities and more evident in rabbits than rats was observed. There was eventual mixing of two dusts inhaled up to 7 months apart. Dust deposited last is cleared first because of less tortuous route.

Estimation of respirable dust exposure among coal miners in South Africa.

Science.gov (United States)

Naidoo, Rajen; Seixas, Noah; Robins, Thomas

2006-06-01

The use of retrospective occupational hygiene data for epidemiologic studies is useful in determining exposure-outcome relationships, but the potential for exposure misclassification is high. Although dust sampling in the South African coal industry has been a legal requirement for several decades, these historical data are not readily adequate for estimating past exposures. This study describes the respirable coal mine dust levels in three South African coal mines over time. Each of the participating mining operations had well-documented dust sampling information that was used to describe historical trends in dust exposure. Investigator-collected personal dust samples were taken using standardized techniques from the face, backbye (underground jobs not at the coal face), and surface from 50 miners at each mine, repeated over three sampling cycles. Job histories and exposure information was obtained from a sample of 684 current miners and 188 ex-miners. Linear models were developed to estimate the exposure levels associated with work in each mine, exposure zone, and over time using a combination of operator-collected historical data and investigator-collected samples. The estimated levels were then combined with work history information to calculate cumulative exposure metrics for the miner cohort. The mean historical and investigator-collected respirable dust levels were within international norms and South African standards. Silica content of the dust samples was also below the 5% regulatory action level. Mean respirable dust concentrations at the face, based on investigator-collected samples, were 0.9 mg/m(3), 1.3 mg/m(3), and 1.9 mg/m(3) at Mines 1, 2, and 3, respectively. The operator-collected samples showed considerable variability across exposure zones, mines, and time, with the annual means at the face ranging from 0.4 mg/m(3) to 2.9 mg/m(3). Statistically significant findings were found between operator- and investigator-collected dust samples. Model

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,...

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.

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.

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.

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...

Use of pyrolysis gases from biogenic fuels as reductionfuels in coal dust furnaces; Einsatz von Pyrolysegasen aus biogenen Brennstoffen als Reduktionsbrennstoff in Kohlestaubfeuerungen

Energy Technology Data Exchange (ETDEWEB)

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

1997-12-31

Co-combustion of refuse-derived fuels in the form of pyrolysis gases, with coal as primary fuel, has advantages in terms of fuel ash separation and nitric oxide emissions. Biomass or sewage sludge is degassed in a pyrolysis reactor, and the gas is used as secondary fuel in a coal dust furnace. The authors investigated the influence of reaction temperature, fuel moisture and reaction atmosphere in the pyrolysis stage on the product fractions gas, tar, and residual fuel, as well as the suitability of the resulting pyrolysis gas as secondary fuel in a coal dust furnace for the purpose of reducing nitric oxide emissions. (orig) [Deutsch] Ein am IVD betriebenes Konzept der Mitverbrennung von Brennstoffen in Form von Pyrolysegasen bietet Vorteile bezueglich der Trennung der Brennstoffaschen und Stickoxidemissionen bei der Feuerung des Primaerbrennstoffes Steinkohle. Biomasse oder Klaerschlamm wird hierbei in einem Pyrolysereaktor engast und gasfoermig als Sekundaerbrennstoff in einer Kohlenstaubfeuerung eingesetzt. Untersuchungsschwerpunkte in der Pyrolysestufe des Prozesses waren die Einfluesse von Reaktionstemperatur, Brennstofffeuchte und Reaktionsatmosphaere auf die Produktfraktionen Gas, Teer und Restbrennstoff sowie die Eignung des erzeugten Pyrolysegases als Sekundaerbrennstoff in einer Kohlenstaubfeuerung zur Senkung derKohlendioxidemissione. (orig)

Use of pyrolysis gases from biogenic fuels as reductionfuels in coal dust furnaces; Einsatz von Pyrolysegasen aus biogenen Brennstoffen als Reduktionsbrennstoff in Kohlestaubfeuerungen

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

Co-combustion of refuse-derived fuels in the form of pyrolysis gases, with coal as primary fuel, has advantages in terms of fuel ash separation and nitric oxide emissions. Biomass or sewage sludge is degassed in a pyrolysis reactor, and the gas is used as secondary fuel in a coal dust furnace. The authors investigated the influence of reaction temperature, fuel moisture and reaction atmosphere in the pyrolysis stage on the product fractions gas, tar, and residual fuel, as well as the suitability of the resulting pyrolysis gas as secondary fuel in a coal dust furnace for the purpose of reducing nitric oxide emissions. (orig) [Deutsch] Ein am IVD betriebenes Konzept der Mitverbrennung von Brennstoffen in Form von Pyrolysegasen bietet Vorteile bezueglich der Trennung der Brennstoffaschen und Stickoxidemissionen bei der Feuerung des Primaerbrennstoffes Steinkohle. Biomasse oder Klaerschlamm wird hierbei in einem Pyrolysereaktor engast und gasfoermig als Sekundaerbrennstoff in einer Kohlenstaubfeuerung eingesetzt. Untersuchungsschwerpunkte in der Pyrolysestufe des Prozesses waren die Einfluesse von Reaktionstemperatur, Brennstofffeuchte und Reaktionsatmosphaere auf die Produktfraktionen Gas, Teer und Restbrennstoff sowie die Eignung des erzeugten Pyrolysegases als Sekundaerbrennstoff in einer Kohlenstaubfeuerung zur Senkung derKohlendioxidemissione. (orig)

Environmental benefits and drawbacks of composite fuels based on industrial wastes and different ranks of coal.

Science.gov (United States)

Nyashina, G S; Vershinina, K Yu; Dmitrienko, M A; Strizhak, P A

2018-04-05

A promising solution to many problems that thermal power industry is facing today would be switching from conventional coal dust combustion to coal-water slurries containing petrochemicals (CWSP). Here, we perform an experimental study of the most hazardous anthropogenic emissions (sulfur and nitrogen oxides) from the combustion of high-potential CWSP. We identify the main benefits and potential drawbacks of using CWSP in thermal power industry. A set of components and additives to CWSP are explored that significantly affect the environmental and energy performance of fuels. The anthropogenic emissions from the combustion of CWSP made of widespread coal and oil processing wastes are no higher than those from coal dust combustion. Using specialized additives to CWSP, we can change the concentrations of NO x and SO x several times. The most appealing additives to CWSP are sawdust, straw, charcoal, limestone, and glycerol. They provide better environmental, economic, and energy performance and improve the rheological properties of CWSP. Waste oils and oil sludge added to CWSP may impair the environmental performance but boost the cost and energy efficiency. Using coal-water slurries containing petrochemicals as a fuel at thermal power plants is an environmentally friendly as well as cost- and energy-efficient way to recover industrial wastes. Copyright © 2018 Elsevier B.V. All rights reserved.

Waste and dust utilisation in shaft furnaces

Energy Technology Data Exchange (ETDEWEB)

Senk, D.; Babich, A.; Gudenau, H.W. [Rhein Westfal TH Aachen, Aachen (Germany)

2005-07-01

Wastes and dusts from steel industry, non-ferrous metallurgy and other branches can be utilised e.g. in agglomeration processes (sintering, pelletising or briquetting) and by injection into shaft furnaces. This paper deals with the second way. Combustion and reduction behaviour of iron- and carbon-rich metallurgical dusts and sludges containing lead, zinc and alkali as well as other wastes with and without pulverised coal (PC) has been studied when injecting into shaft furnaces. Following shaft furnaces have been examined: blast furnace, cupola furnace, OxiCup furnace and imperial-smelting furnace. Investigations have been done at laboratory and industrial scale. Some dusts and wastes under certain conditions can be not only reused but can also improve combustion efficiency at the tuyeres as well as furnace performance and productivity.

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...

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.

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.

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.

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)

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.

The Spontaneous Combustion of Railway Ties and Asphalt Shingles

Science.gov (United States)

Leslie, Geoffrey

Many Low Carbon Fuels (LCFs) present unknown spontaneous combustion risks, which must be quantified before their use as fossil fuel replacements. Wood and coal spontaneous combustion is well understood; however, LCFs weather, and subsequent chemical changes could affect their spontaneous combustion properties. LCF spontaneous combustion could lead to accidental fires with possible loss of life, limb and property. The spontaneous combustion risks of two LCFs, discarded creosote-treated wooden railway ties and roofing asphalt shingles, were investigated with calorimetry and heat transfer experiments. Chemical changes due to weathering were studied with pyrolysis-Gas Chromatography/Mass Spectrometry (py-GC/MS). Creosote-treated wooden railway tie dust, roofing asphalt shingle particles, poplar wood pellets, and petroleum coke self-heating were studied with isothermal calorimetry. Railway tie dust and asphalt shingle heat transfer were characterized with a guarded hot plate. Petroleum coke self-heating was consistent with coal, while both poplar pellets and railway tie dust were found to be more reactive compared to oven test results of similar materials. The observed increase in reactivity was probably a result of significant moisture contenint in the pellet and railway tie dust. Critical conditions for spontaneous combustion were evaluated with the Frank-Kamenetskii parameter, assuming an ambient temperature of 40°C and constant moisture content. Kamenetskii calculations indicate that a 1.6 m cube of railway tie dust, or a 58 m cube of asphalt particles, would be unstable and combust. LCF chemistry may have been affected by weathering, which would cause chemical changes that affect their spontaneous combustion properties. Therefore, railway tie wood and roofing asphalt shingle chemistry were investigated by identifying products of 250° and 550°C pyrolysis with py-GC/MS. Railway tie wood pyrolyzates did not show signs of weathering; in contrast, asphalt pyrolysis

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

Dust control in Belgian coal mines. Position at the beginning of 1975

Energy Technology Data Exchange (ETDEWEB)

Preat, B; Vanstraelen, M

1975-01-01

A general view is given of dust control in Belgian coal mines at the beginning of 1975. The statistical data received from the mines are presented in tabular form. The length and the output of coal faces treated by the classical methods of pre-spraying of the wall, wet cutting, water infusion and wet pneumatic picks are given separately; in some cases two or more of these techniques are used together on the same coalface. The number of rock headings in which different methods of dust control are used is also given.

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...

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.

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

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.

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.

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.

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.

Miners' lung: a history of dust disease in British coal mining

Energy Technology Data Exchange (ETDEWEB)

Arthur McIvor; Ronald Johnston

2007-02-15

The authors explore the experience of coal miners' lung diseases and the attempts at voluntary and legal control of dusty conditions in British mining from the late nineteenth century to the present. In this way, the book addresses the important issues of occupational health and safety within the mining industry. The authors examine the prevalent diseases, notably pneumoconiosis, emphysema and bronchitis, and evaluate the roles of key players such as the doctors, management and employers, the state and the trade unions. Contents are: General editor's preface; Introduction. Part 1 Interpretations and Context: Methodology and historiography; Work and the body in coalmining. Part 2 Advancing Medical Knowledge on Dust Disease: Coal workers' pneumoconiosis: discovery and denial; Social medicine and pioneering epidemiology; The last gasp: bronchitis and emphysema. Part 3 The Industrial Politics of Miners' Lung: 'Enlightened management'? The NCB, the state and dust; The trade unions and dust. Part 4 Miners' Testimonies: Dust and Disability Narratives: Workplace culture: risk and masculinity; Breathless men: living and dying with dust disease. Conclusion. 3 figs., 10 tabs., 1 app.

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.

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...

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.

78 FR 27442 - Coal Mine Dust Sampling Devices; Correction

Science.gov (United States)

2013-05-10

... DEPARTMENT OF LABOR Mine Safety and Health Administration Coal Mine Dust Sampling Devices; Correction AGENCY: Mine Safety and Health Administration, Labor. ACTION: Notice; correction. SUMMARY: On April 30, 2013, Mine Safety and Health Administration (MSHA) published a notice in the Federal Register...

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...

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

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.

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

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.)

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...

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.

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

Result of design and test operation of a coal boiler at Hyogo Refinery

Energy Technology Data Exchange (ETDEWEB)

Miura, Yasuhiko; Sato, Noriyuki

1987-05-01

This boiler is the first coal boiler for the oil refineries in Japan (Installed in Oct., 1986 at Idemitsu Petrochemical Co.) Causes for using coal as a fuel are a conversion to less expensive fuel and offering a technical service to the users of coal through the combustion of coal and learning of a handling technique. The type of boiler is Babcock single barrel radiant type and has 150 t/d capacity with single fuel combustion of coal. Auxiliary equipments are a pulverizer, a transportation and storage unit, a denitration unit, a dust collector, a desulfurization unit, and an ash disposal unit. Main considerations in the design are measures for the security of finely pulverized coal, clogging prevention for coal and ash. A test operation revealed 7 % of combustible loss and 160 - 250 ppm of NOx content at a charge inlet of denitration unit. Actual operation exhibited no clogging at the denitration unit of troubles due to scaling. Design for raw materials is to blend 4 imported coals (from Australia and Canada, etc) and 3 Japanese ones. (7 figs, 2 tabs)

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...

Genotoxic Evaluation of Mikania laevigata Extract on DNA Damage Caused by Acute Coal Dust Exposure

Energy Technology Data Exchange (ETDEWEB)

Freitas, T.P.; Heuser, V.D.; Tavares, P.; Leffa, D.D.; da Silva, G.A.; Citadini-Zanette, V.; Romao, P.R.T.; Pinho, R.A.; Streck, E.L.; Andrade,V.M. [University of Extremo Catarinense, Criciuma, SC (Brazil)

2009-06-15

We report data on the possible antigenotoxic activity of Mikania laevigata extract (MLE) after acute intratracheal instillation of coal dust using the comet assay in peripheral blood, bone marrow, and liver cells and the micronucleus test in peripheral blood of Wistar rats. The animals were pretreated for 2 weeks with saline solution (groups 1 and 2) or MLE (100 mg/kg) (groups 3 and 4). On day 15, the animals were anesthetized with ketamine (80 mg/kg) and xylazine (20 mg/kg), and gross mineral coal dust (3 mg/0.3 mL saline) (groups 2 and 4) or saline solution (0.3 mL) (groups 1 and 3) was administered directly in the lung by intratracheal administration. Fifteen days after coal dust or saline instillation, the animals were sacrificed, and the femur, liver, and peripheral blood were removed. The results showed a general increase in the DNA damage values at 8 hours for all treatment groups, probably related to surgical procedures that had stressed the animals. Also, liver cells from rats treated with coal dust, pretreated or not with MLE, showed statistically higher comet assay values compared to the control group at 14 days after exposure. These results could be expected because the liver metabolizes a variety of organic compounds to more polar by-products. On the other hand, the micronucleus assay results did not show significant differences among groups. Therefore, our data do not support the antimutagenic activity of M. laevigata as a modulator of DNA damage after acute coal dust instillation.

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.

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

PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States

Science.gov (United States)

Van Metre, P.C.; Mahler, B.J.; Wilson, J.T.

2009-01-01

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-tar-based sealcoat dominates use, and three cities in the western U. S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2. 1 and 0. 8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

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.

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.

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.

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.

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.

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)

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.

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).

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)

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

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.

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%.

Innovation Developments of Coal Chemistry Science in L.M. Litvinenko Institute of Physical-Organic Chemistry and Coal Chemistry of NAS of Ukraine

Directory of Open Access Journals (Sweden)

Shendrik, T.G.

2015-11-01

Full Text Available The article presents short historical review and innovation developments of Coal Chemistry Department of L.M. Litvinenko Institute, NAS of Ukraine connected with coal mine exploitation problems, search for decisions toward prevention of spontaneous combustion, dust control in mines, establishing structural chemical features of coal with different genesis and stages of metamorphism with the aim to develop new methods of their modification and rational use. The methods of obtaining inexpensive sorbents from Ukrainian raw materials (including carbon containing waste are proposed. The problems of modern coal chemistry science in IPOCC of NAS of Ukraine are outlined.

Determine the feasibility of techniques for simulating coal dust explosions

CSIR Research Space (South Africa)

Kirsten, JT

1994-07-01

Full Text Available The primary objective of this work is to assess the feasibility of reliably simulating the coal dust explosion process taking place in the Kloppersbos tunnel with a computer model. Secondary objectives are to investigate the viability of simulating...

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.

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.

PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States

Energy Technology Data Exchange (ETDEWEB)

Peter C. Van Metre; Barbara J. Mahler; Jennifer T. Wilson [U.S. Geological Survey, Austin, TX (USA)

2009-01-15

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U.S. cities that show nationwide patterns in concentrations of {Sigma}PAHs associated with sealcoat. Dust was swept from parking lots in six cities in the central and eastern U.S., where coal-tar-based sealcoat dominates use, and three cities in the western U.S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2.1 and 0.8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo(a)pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted. 30 refs., 4 figs., 2 tabs.

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

Detonation limits of clouds of coal dust in mixtures of oxygen and nitrogen

Energy Technology Data Exchange (ETDEWEB)

Edwards, D.H.; Fearnley, P.J.; Nettleton, M.A.

1987-09-01

Ignition and the subsequent acceleration of flame in clouds of coal dust dispersed in mixtures of oxygen and nitrogen have been studied. Two coal sizes, 24 and 54 ..mu..m, in concentrations ranging from 0.05 to 0.22 kg/m/sup 3/ were employed. Flame acceleration and the approach to transition to a stable detonation were monitored by a combination of microwave interferometry and pressure measurements. Flame and shock velocities up to 1.85 km/sec were observed. Ignition distances were found to be independent of the concentrations of dust and oxygen and particle size.

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.

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.

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.

Comparison of the CAS-POL and IOM samplers for determining the knockdown efficiencies of water sprays on float coal dust.

Science.gov (United States)

Seaman, Clara E; Shahan, Michael R; Beck, Timothy W; Mischler, Steven E

2018-03-01

Float coal dust, generated by mining operations, is distributed throughout mine airways by ventilating air designed to purge gases and respirable dust. Float coal dust poses an explosion hazard in the event of a methane ignition. Current regulation requires the application of inert rock dust in areas subjected to float coal dust in order to mitigate the hazard. An alternate method using water sprays, which have been effective in controlling respirable dust hazards, has been proposed as a way to control float coal dust generated on longwall faces. However, the knockdown efficiency of the proposed water sprays on float coal dust needs to be verified. This study used gravimetric isokinetic Institute of Occupational Medicine (IOM) samplers alongside a real-time aerosol monitor (Cloud Aerosol Spectrometer with polarization; CAS-POL) to study the effects of spray type, operating pressure, and spray orientation on knockdown efficiencies for seven different water sprays. Because the CAS-POL has not been used to study mining dust, the CAS-POL measurements were validated with respect to the IOM samplers. This study found that the CAS-POL was able to resolve the same trends measured by the IOM samplers, while providing additional knockdown information for specific particle size ranges and locations in the test area. In addition, the CAS-POL data was not prone to the same process errors, which may occur due to the handling of the IOM filter media, and was able to provide a faster analysis of the data after testing. This study also determined that pressure was the leading design criteria influencing spray knockdown efficiency, with spray type also having some effect and orientation having little to no effect. The results of this study will be used to design future full-scale float coal dust capture tests involving multiple sprays, which will be evaluated using the CAS-POL.

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.

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.

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

A systematic review of occupational exposure to coal dust and the risk of interstitial lung diseases

DEFF Research Database (Denmark)

Beer, Christiane; Kolstad, Henrik A; Søndergaard, Klaus

2017-01-01

Objective: Exposure to coal dust can cause interstitial lung disease (ILD), but whether this is due to pure coal or to the contents of quartz in coal is less clear. Here, we systematically reviewed the relation between 'pure coal' and ILD. Methods: In a systematic review based on PRISMA criteria...

A systematic review of occupational exposure to coal dust and the risk of interstitial lung diseases

NARCIS (Netherlands)

Beer, Christiane; Kolstad, Henrik A; Søndergaard, Klaus; Bendstrup, Elisabeth; Heederik, Dick; Olsen, Karen E; Omland, Øyvind; Petsonk, Edward; Sigsgaard, Torben; Sherson, David L; Schlünssen, Vivi

2017-01-01

Objective: Exposure to coal dust can cause interstitial lung disease (ILD), but whether this is due to pure coal or to the contents of quartz in coal is less clear. Here, we systematically reviewed the relation between 'pure coal' and ILD. Methods: In a systematic review based on PRISMA criteria

Evaluation of laser-induced breakdown spectroscopy (LIBS) for measurement of silica on filter samples of coal dust.

Science.gov (United States)

Stipe, Christopher B; Miller, Arthur L; Brown, Jonathan; Guevara, Edward; Cauda, Emanuele

2012-11-01

Airborne silica dust (quartz) is common in coal mines and represents a respiratory hazard that can lead to silicosis, a potentially fatal lung disease. With an eye toward developing a portable monitoring device for rapid analysis of silica dust, laser-induced breakdown spectroscopy (LIBS) was used to quantify quartz in coal dust samples collected on filter media. Pure silica (Min-U-Sil™ 5), Georgia kaolin, and Pittsburgh-4 and Illinois-6 coal dusts were deposited separately and at multiple mass loadings onto 37-mm polyvinylchloride (PVC) filters. LIBS-generated silicon emission was monitored at 288.16 nm, and non-silica contributions to that signal from kaolinite were removed by simultaneously detecting aluminum. Measurements of the four samples were used to calculate limits of detection (LOD) for silicon and aluminum of approximately 0.08 μg/cm(2) and 0.05 μg/cm(2), respectively (corresponding to 0.16 μg/cm(2) and 0.20 μg/cm(2) for silica and kaolinite, respectively). Relative errors of prediction are around 10%. Results demonstrate that LIBS can dependably quantify silica on filter samples of coal dust and confirm that accurate quantification can be achieved for very lightly loaded samples, which supports the potential application of LIBS for rapid, in-field monitoring.

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)

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

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.

Regulator of Dust and Coal Burner of Power Boilers

Directory of Open Access Journals (Sweden)

W. Wujcik

2004-01-01

Full Text Available The papers considers problems concerning introduction of neutron regulator into engineering practice. The regulator makes it possible to regulate CO, N0^ and O2 values with the purpose to optimize ejections into environment. The paper contains scheme of automation control of cyclone dust and coal burner with the help of a neutron regulator.

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...

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Emphysema and pulmonary impairment in coal miners: Quantitative relationship with dust exposure and cigarette smoking

Science.gov (United States)

Kuempel, E. D.; Vallyathan, V.; Green, F. H. Y.

2009-02-01

Coal miners have been shown to be at increased risk of developing chronic obstructive pulmonary diseases including emphysema. The objective of this study was to determine whether lifetime cumulative exposure to respirable coal mine dust is a significant predictor of developing emphysema at a clinically-relevant level of severity by the end of life, after controlling for cigarette smoking and other covariates. Clinically-relevant emphysema severity was determined from the association between individuals' lung function during life (forced expiratory volume in one second, FEV1, as a percentage of predicted normal values) and emphysema severity at autopsy (as the proportion of lung tissue affected). In a logistic regression model, cumulative exposure to respirable coal mine dust was a statistically significant predictor of developing clinically-relevant emphysema severity, among both ever-smokers and never-smokers. The odds ratio for developing emphysema associated with FEV1 <80% at the cohort mean cumulative coal dust exposure (87 mg/m3 x yr) was 2.30 (1.46-3.64, 95% confidence limits), and at the cohort mean cigarette smoking (among smokers: 42 pack-years) was 1.95 (1.39-2.79).

Emphysema and pulmonary impairment in coal miners: quantitative relationship with dust exposure and cigarette smoking

Energy Technology Data Exchange (ETDEWEB)

E.D. Kuempel; V. Vallyathan; F.H.Y. Green [National Institute for Occupational Safety and Health, Cincinnati, OH (United States)

2009-07-01

Coal miners have been shown to be at increased risk of developing chronic obstructive pulmonary diseases including emphysema. The objective of this study was to determine whether lifetime cumulative exposure to respirable coal mine dust is a significant predictor of developing emphysema at a clinically-relevant level of severity by the end of life, after controlling for cigarette smoking and other covariates. Clinically-relevant emphysema severity was determined from the association between individuals' lung function during life (forced expiratory volume in one second, FEV{sub 1}, as a percentage of predicted normal values) and emphysema severity at autopsy (as the proportion of lung tissue affected). In a logistic regression model, cumulative exposure to respirable coal mine dust was a statistically significant predictor of developing clinically-relevant emphysema severity, among both ever-smokers and never-smokers. The odds ratio for developing emphysema associated with FEV1 <80% at the cohort mean cumulative coal dust exposure (87 mg/m{sup 3} x yr) was 2.30 (1.46-3.64, 95% confidence limits), and at the cohort mean cigarette smoking (among smokers: 42 pack-years) was 1.95 (1.39-2.79). 20 refs., 2 figs., 2 tabs.

Emphysema and pulmonary impairment in coal miners: Quantitative relationship with dust exposure and cigarette smoking

Energy Technology Data Exchange (ETDEWEB)

Kuempel, E D [National Institute for Occupational Safety and Health, Education and Information Division, Risk Evaluation Branch, Cincinnati, Ohio (United States); Vallyathan, V [National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Pathology and Physiology Research Branch, Morgantown, West Virginia (United States); Green, F H Y, E-mail: ekuempel@cdc.go [Department of Pathology, Faculty of Medicine, University of Calgary, Calgary, Alberta (Canada)

2009-02-01

Coal miners have been shown to be at increased risk of developing chronic obstructive pulmonary diseases including emphysema. The objective of this study was to determine whether lifetime cumulative exposure to respirable coal mine dust is a significant predictor of developing emphysema at a clinically-relevant level of severity by the end of life, after controlling for cigarette smoking and other covariates. Clinically-relevant emphysema severity was determined from the association between individuals' lung function during life (forced expiratory volume in one second, FEV{sub 1}, as a percentage of predicted normal values) and emphysema severity at autopsy (as the proportion of lung tissue affected). In a logistic regression model, cumulative exposure to respirable coal mine dust was a statistically significant predictor of developing clinically-relevant emphysema severity, among both ever-smokers and never-smokers. The odds ratio for developing emphysema associated with FEV{sub 1} <80% at the cohort mean cumulative coal dust exposure (87 mg/m{sup 3} x yr) was 2.30 (1.46-3.64, 95% confidence limits), and at the cohort mean cigarette smoking (among smokers: 42 pack-years) was 1.95 (1.39-2.79).

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.

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.

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.

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.

Investigations of coal ignition in a short-range flame burner using optical measuring systems; Untersuchungen zur Kohlezuendung am Flachflammenbrenner unter Verwendung optischer Messtechnik

Energy Technology Data Exchange (ETDEWEB)

Hackert, G.; Kremer, H.; Wirtz, S. [Bochum Univ. (Germany). Lehrstuhl fuer Energieanlagentechnik

1999-09-01

The short-range flame burner and the KOALA reactor of DMT are experimental facilities for realistic simulation of coal conversion processes at high temperatures and pressures in atmospheric conditions. The TOSCA system enable measurements of temperatures, sizes, shapes and velocities of the fuel particles, which serve as a basis for a three-dimensional simulation model of coal combustion. In the future, further parameter studies will deepen the present knowledge of coal dust combustion under pressure and enable optimisation of the numerical models for simulation of industrial-scale systems for coal dust combustion under pressure. [Deutsch] Mit dem Flachflammenbrenner und dem KOALA-Reaktor der DMT stehen Versuchsapparaturen zur Verfuegung, mit deren Hilfe die Kohleumwandlungsprozesse bei hohen Temperaturen unter Druck und unter atmosphaerischen Bedingungen realistisch wiedergegeben werden. Das TOSCA-System erlaubt dabei die Bestimmung von Temperaturen, Groessen, Formen und Geschwindigkeiten der Brennstoffpartikel. Diese Daten liefern die Grundlage fuer die Erstellung eines dreidimensionalen Simulationsmodells zur Modellierung der Kohleverbrennung. In Zukunft werden weitere Parameterstudien das Verstaendnis der Kohlenstaubdruckverbrennung vertiefen und ein Optimierung der numerischen Modelle ermoeglichen, so dass die Simulation grosstechnischer Kohlenstaubdruckverbrennungsanlagen realisiert werden kann. (orig.)

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.

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

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...

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.

Quantification of Inherent Respirable Dust Generation Potential (IRDGP) of South African Coals

CSIR Research Space (South Africa)

Phillips, H

2003-08-01

Full Text Available Advisory Committee Project Summary Project Title: Inherent Respirable Dust Generation Potential (IRDGP) of South African Coals-SIM020604 Author(s): H.R.Phillips and B. K. Belle Agency: University of Witwatersrand Report Date: July2003... Related Projects: Health 607, Sim 02-06-03 Category: Occupational Health Applied Research Occupational Hygiene Summary Project SIM020604 was formulated to determine the Inherent Respirable Dust Generation Potential (IRDGP) of various South...

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.

Carbon formation and metal dusting in hot-gas cleanup systems of coal gasifiers

Energy Technology Data Exchange (ETDEWEB)

Judkins, R.R.; Tortorelli, P.F.; Judkins, R.R.; DeVan, J.H.; Wright, I.G. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1995-11-01

The product gas resulting from the partial oxidation of Carboniferous materials in a gasifier is typically characterized by high carbon and sulfur, but low oxygen, activities and, consequently, severe degradation of the structural and functional materials can occur. The objective of this task was to establish the potential risks of carbon deposition and metal dusting in advanced coal gasification processes by examining the current state of knowledge regarding these phenomena, making appropriate thermochemical calculations for representative coal gasifiers, and addressing possible mitigation methods. The paper discusses carbon activities, iron-based phase stabilities, steam injection, conditions that influence kinetics of carbon deposition, and influence of system operating parameters on carbon deposition and metal dusting.

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...

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)

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.

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

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.

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.

Effect of phosphorous transformation on the reduction of PM{sub 10} formation during Co-combustion of coal and sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Zhuo, J.K.; Dong, M.; Li, G.D.; Li, S.Q.; Song, Q.; Yao, Q. [Tsinghua Univ., Beijing (China). Key Lab. of Thermal Science and Power Engineering; Duan, L. [Tsinghua Univ., Beijing (China). Dept. of Environmental Science and Engineering

2013-07-01

Co-combustion of Municipal Sewage Sludge with coal will become increasingly widely used, regarded as an important incineration method with the high thermal efficiency, low emissions, low investment and operating costs. However, the presence of phosphorus in fine particle has gained increased attention due to its environmental adverse affection and deactivation of SCR DeNOx catalysts. Therefore, the behavior of phosphorus in fine particles during co-combustion of coal and sewage sludge was investigated in a 25 kW quasi one-dimensional down-fired pulverized coal combustor, where PM{sub 10} was collected from the furnace centerline in the outlet of flue gas cooler by using a two-stage nitrogen-aspirated, water-cooling isokinetic sampling probe followed a 13-stage electric low pressure impactor. Then the formation mechanism of PM{sub 10} was investigated by observing the different fractions of sewage sludge in the coal. Similar to the coal combustion, the particle-size-distributions (PSD) of PM{sub 10} mass concentration by co-combustion of sewage sludge with coal exhibit two distinct modes separated by a fraction of 0.157-0.263 {mu}m, ultrafine mode and intermediate mode. With the sewage sludge blended sludge up to 15% (thermal ratio), the mass concentration of the total fly ash and PM{sub 10+} (Dp > 10 {mu}m) vastly increased from 1,088 and 547 mg/Nm{sup 3} (during coal combustion) to 5,059 and 4,403 mg/Nm{sup 3}. However, the mass concentration of fine particulates, such as PM{sub 1}, PM{sub 2.5} and PM{sub 10} was maintained at the emission level of coal combustion. When the fraction of sewage sludge less than 15%, the mass concentration of fine particle is higher than the emission during coal combustion, while the growth rate is only by the 3.6, 7.9 and 4.8% of the total concentration of fly ash (5% thermal). The change of the PSD of mass concentration during co- combustion of sewage sludge and coal, mainly was caused by the interaction between Si, Al and Ca, Fe

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

Investigation into the potential for dust and gas explosions in underground coal mines with reference to pick tip geometry

International Nuclear Information System (INIS)

Dawood, Albert D.

2011-01-01

In underground coal mines, methane gas, if present in sufficient concentration, may be ignited by sparks from hot spots on the picks of coal cutting machines striking hard bands of rock. During the coal cutting, wear-flat areas develop on the trailing side of the tips of picks. As pick wear progresses, the generation of frictional heat and coal dust increases and the development of hot spots at the cutting tips may lead to an explosion of methane gas. Field experience and research work over the last few years have facilitated excellent cutting performance for certain picks through the optimisation of the cutting parameters. Such performance improvements show great promise in preventing the incidence of gas or dust explosions occurring at the coal face area. This study sets out some of the fundamentals of pick geometry and cutting parameters and the methods which have been employed to achieve improvements in reducing the hazards of gas or dust explosions. It is based on the comparative trial results of two types of picks with different designs and on a range of available research information on the subject. My investigation looked at the fundamentals of pick geometry and cutting parameters and the current suppression techniques in place to control the dust and gas explosions on the coal operating face.

Identifying sources of respirable quartz and silica dust in underground coal mines in southern West Virginia, western Virginia, and eastern Kentucky

Energy Technology Data Exchange (ETDEWEB)

Schatzel, Steven J. [National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, 626 Cochrans Mill Road, PO Box 18070, Pittsburgh, PA 15236 (United States)

2009-04-01

Prior research has suggested that the source of respirable silica dust in underground coal mines is typically the immediate top or bottom lithology adjacent to the mined seam, not mineral matter bound within the mined coal bed. Geochemical analyses were applied in an effort to identify the specific source rock of respirable quartz dust in coal mines. The analyses also demonstrate the compositional changes that take place in the generation of the respirable dust fraction from parent rock material. All six mine sites were mining coal with relatively low mineral matter content, although two mines were operating in the Fire Clay coal bed which contains a persistent tonstein. Interpretations of Ca, Mg, Mn, Na, and K concentrations strongly suggest that the top strata above the mined seam is the primary source of mineral dust produced during mining. One site indicates a mixed or bottom source, possibly due to site specific conditions. Respirable dust compositional analyses suggest a direct relationship between the quantity of mineral Si and the quantity of quartz Si. A similar relationship was not found in either the top or bottom rocks adjacent to the mined seam. An apparent loss of elemental Al was noted in the respirable dust fraction when compared to potential parent rock sources. Elemental Al is present in top and bottom rock strata within illite, kaolinite, feldspar, and chlorite. A possible explanation for loss of Al in the respirable dust samples is the removal of clays and possibly chlorite minerals. It is expected that removal of this portion of the Al bearing mineral matter occurs during rock abrasion and dust transport prior to dust capture on the samplers. (author)

Occurrence of lead, copper, zinc, and arsenic compounds in atmospheric dusts, and the sources of these impurities

Energy Technology Data Exchange (ETDEWEB)

Dunn, J T; Bloxam, H C.L.

1933-06-30

The authors indicate that the combustion of fossil fuels such as coal for industrial and electrical power causes the deposition of zinc, arsenic, copper, and lead which are then found in the dust and soots of most urban areas. They express the fear that these dusts, if not poisonous, may be expected to be injurious to the health of man, animals, and plants.

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.

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.

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.

Control of coal-dust in mines. Second edition. Bor'ba s ugol'noi i porodnoi pyl'yu v shakhtakh

Energy Technology Data Exchange (ETDEWEB)

Pemrukhin, P.M.; Grodel, G.S.; Zhilyaev, N.I.; Korenev, A.P.; Krivokhizha, B.M.; Kul' bachnyi, A.N.; Lyubimoba, A.I.; Medvedev, E.N.; Yaremachenko, P.P.

1981-01-01

An examination is made of problems concerned with over-all removal of dust from the air in mines. A description is given of physical and physico-chemical properties of ore mine dust that are of importance to evaluating processes in the formation, propagation and suppression of dust. Results are given for theoretical and on-site studies of dust aerodynamics in mines. A presentation is made of contemporary measures for controlling coal and rock dust in mines as well as means and methods of controlling air dust-level. Technical characteristics are given for new instruments for measuring air dust level. Brief data are given on preliminary wetting of coal in a massif, and a discussion is made of theoretical and practical problems related to hydro-dedusting, dust suppression, and dust removal during the operation of mining machinery as well as instruments for dedusting air on the surface complex of a mine. The book is intended for engineering-technical personnel in coal mines, design-planning and scientific-research institutes. 52 references, 61 tables.

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....

Cooperation in simulating a pressurized coal dust reactor with different simulation programs; Kooperation bei der Simulation eines Druckkohlenstaubreaktors mit unterschiedlichen Simulationsprogrammen

Energy Technology Data Exchange (ETDEWEB)

Ayar, A.; Hecken, M. [Technische Hochschule Aachen (Germany). Lehrstuhl fuer Waermeuebertragung und Klimatechnik; Mohr, M.; Murza, S. [Bochum Univ. (Germany). Lehrstuhl fuer Energieanlagentechnik; Richter, S.; Stroehle, J. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

1999-09-01

The contribution presents the results of a cooperative project of three different universities - Department of Heat Transfer and Air Conditioning Engineering (WUeK) of RWTH Aachen, Department of Power Sytems Engineering (LEAT) of Ruhr-Universitaet Bochum, Institute of Chemical Engineering and Steam Boiler Engineering (IVD) of Stuttgart University - which involved modellilng a benchmark flame of the pressurized coal dust reactor of the Departmentof Heat Transfer and Air Conditioning Engineering. The conditions of the benchmark flame reflect a real firnace condition which so far has never been investigated experimentally. The contribution compares the results of the three different simulation programs and presents an outlook to the necessary further developments of the programs for modelling plants for pressurized coal dust combustion. [Deutsch] Es werden die Ergebnisse der Zusammenarbeit der drei beteiligten Institute - Lehrstuhl fuer Waermeuebertragung und Klimatechnik (WUeK) der RWTH Aachen, Lehrstuhl fuer Energieanlagentechnik (LEAT) der Ruhr-Uni Bochum und Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Uni Stuttgart - bei der Modellierung einer Benchmarkflamme des Druckkohlenstaubreaktors am Lehrstuhl fuer Waermeuebertragung und Klimatechnik dargestellt. Diese Bedingungen fuer diese Benchmarkflamme sind einem realen, bis dato noch nicht experimentell untersuchten Feuerungszustand nachempfunden. Der Beitrag beinhaltet den Vergleich der mit drei unterschiedlichen Simulationsprogrammen erzielten Ergebnisse und gibt einen Ausblick auf die notwendigen Weiterentwicklungen der Programme hinsichtlich der Modellierung druckkohlenstaubgefeuerter Anlagen. (orig.)

Modeling the biogeochemical impact of atmospheric phosphate deposition from desert dust and combustion sources to the Mediterranean Sea

Science.gov (United States)

Richon, Camille; Dutay, Jean-Claude; Dulac, François; Wang, Rong; Balkanski, Yves

2018-04-01

Daily modeled fields of phosphate deposition to the Mediterranean from natural dust, anthropogenic combustion and wildfires were used to assess the effect of this external nutrient on marine biogeochemistry. The ocean model used is a high-resolution (1/12°) regional coupled dynamical-biogeochemical model of the Mediterranean Sea (NEMO-MED12/PISCES). The input fields of phosphorus are for 2005, which are the only available daily resolved deposition fields from the global atmospheric chemical transport model LMDz-INCA. Traditionally, dust has been suggested to be the main atmospheric source of phosphorus, but the LMDz-INCA model suggests that combustion is dominant over natural dust as an atmospheric source of phosphate (PO4, the bioavailable form of phosphorus in seawater) for the Mediterranean Sea. According to the atmospheric transport model, phosphate deposition from combustion (Pcomb) brings on average 40.5×10-6 mol PO4 m-2 yr-1 over the entire Mediterranean Sea for the year 2005 and is the primary source over the northern part (e.g., 101×10-6 mol PO4 m-2 yr-1 from combustion deposited in 2005 over the north Adriatic against 12.4×10-6 from dust). Lithogenic dust brings 17.2×10-6 mol PO4 m-2 yr-1 on average over the Mediterranean Sea in 2005 and is the primary source of atmospheric phosphate to the southern Mediterranean Basin in our simulations (e.g., 31.8×10-6 mol PO4 m-2 yr-1 from dust deposited in 2005 on average over the south Ionian basin against 12.4×10-6 from combustion). The evaluation of monthly averaged deposition flux variability of Pdust and Pcomb for the 1997-2012 period indicates that these conclusions may hold true for different years. We examine separately the two atmospheric phosphate sources and their respective flux variability and evaluate their impacts on marine surface biogeochemistry (phosphate concentration, chlorophyll a, primary production). The impacts of the different phosphate deposition sources on the biogeochemistry of the

Combustion and environment. The answers from the energy and equipment suppliers; Combustion et environnement. Les reponses des fournisseurs d`energie et d`equipements

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

This paper is a reprint of an article published in `Energie Plus` magazine which questions the capability of commercial fuels and combustion equipments (central heating plants, burners, turbines and engines) available today of respecting the limit values of pollutant emissions (SO{sub x}, NO{sub x}, CO, dusts) of forthcoming regulations. An analysis of the situation is given separately for the fuels (natural gas, coal, heavy fuels) with a stress on the competition aspects, and for the combustion systems (turbines, diesel and gas engines, central heating plants). (J.S.)

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

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

Increased occupational coal dust toxicity in blood of central heating system workers.

Science.gov (United States)

Tuluce, Yasin; Ozkol, Halil; Koyuncu, Ismail; Ine, Hatice

2011-02-01

Coal dust causes lung diseases in occupational exposure. Reactive oxygen species have been implicated in the pathogenesis of its toxicity. In this study, serum enzymes, lipid profile and other biochemical values with oxidant/antioxidant status in whole blood and serum of central heating system workers (CHSW; the persons responsible for heating the apartment with coal) were determined to reflect the cell injury. Blood samples were obtained from CHSW (n = 25) and healthy individuals (n = 25). All values were measured in whole blood and serum. ANOVA was used for the estimation of statistical data. In the group of CHSW, creatinine, ferritin, alanin aminotransferase, aspartate aminotransferase, creatine phosphokinase, gamma glutamyl transferase, lactate dehydrogenase and glutathione reductase activities as well as triglyceride, very low density lipoprotein, protein carbonyl and malondialdehide were significantly higher, while transferrin, high density lipoprotein and catalase (CAT) activities were lower than the group of healthy individuals. This result is consistent with hypothesis that respirable coal dust generates lipid and protein oxidation and induces leakage of serum enzymes by cell damage. It also leads to imbalance in antioxidant defense system, lipid profile and other biochemical parameters.

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.

Subchronic inhalation of coal dust particulate matter 10 induces bronchoalveolar hyperplasia and decreases MUC5AC expression in male Wistar rats.

Science.gov (United States)

Kania, Nia; Setiawan, Bambang; Widjadjanto, Edi; Nurdiana, Nurdiana; Widodo, M Aris; Kusuma, H M S Chandra

2014-10-01

Coal dust is a pollutant found in coal mines that are capable of inducing oxidative stress and inflammation, but the effects on lung metaplasia as an early step of carcinogenesis remain unknown. The purpose of the present study was to evaluate the effects of PM10 coal dust on lung histology, MUC5AC expression, epidermal growth factor (EGF) expression, and epidermal growth factor receptor (EGFR) expression. An experimental study was done on male Wistar rats, which were divided into the following groups: control groups exposed to coal dust for 14 days (at doses of 6.25 mg/m(3), 12.5 mg/m(3), and 25 mg/m(3)), and the groups exposed to coal dust for 28 days (at doses of 6.25 mg/m(3), 12.5 mg/m(3), and 25 mg/m(3)). EGF expressions in rat lungs were measured by ELISA. EGFR and MUC5AC were measured by a confocal laser scanning microscope. The bronchoalveolar epithelial image of the group exposed to coal dust for 14 and 28 days showed a epithelial rearrangement, hyperplastic (metaplastic) goblet cells, and scattered massive inflammatory cells. The pulmonary parenchymal image of the group of exposed to coal dust for 14 and 28 days showed scattered inflammatory cells filling up the pulmonary alveolar networks, leading to an appearance of thickened parenchymal alveoli until emphysema-like structure. There was no significant difference in MUC5AC, EGF, and EGFR expressions for 14-d exposure (p>0.05). There was no significant difference in EGF and EGFR expressions for 28-d exposure (p>0.05), but there was a significant difference in MUC5AC expression (phyperplasia and rearrangement of epithelial cells which accompanied by decrease expression MUC5AC in male rats. Copyright © 2014 Elsevier GmbH. All rights reserved.

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).

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.

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

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.

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

Initiation, Combustion and Transition to Detonation in Homogeneous and Heterogeneous Reactive Mixtures: A Summary

Science.gov (United States)

1981-09-01

undoubtedly associ- uid expanding-vapor explosions, or’ course of an explosion. In buildings ated with the manufacture, handling, BLEVEs , and unconfined...with its need for fossil fuel away, owing to atmospheric inhomo- energy, introduced coal mine explo- geneities, it is heard as a "boom." The blast wave...1947, when the fuels in enclosures compressed-air lines ship Grand Camp caught fire Combustion explosions of dusts In enclosures Coal mines , grain

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.

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.

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.

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.

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

Modeling of the flame propagation in coal-dust- methane air mixture in an enclosed sphere volume

International Nuclear Information System (INIS)

Krainov, A Yu; Moiseeva, K M

2016-01-01

The results of the numerical simulation of the flame front propagation in coal-dust- methane-air mixture in an enclosed volume with the ignition source in the center of the volume are presented. The mathematical model is based on a dual-velocity two-phase model of the reacting gas-dispersion medium. The system of equations includes the mass-conversation equation, the impulse-conversation equation, the total energy-conversation equation of the gas and particles taking into account the thermal conductivity and chemical reactions in the gas and on the particle surface, mass-conversation equation of the mixture gas components considering the diffusion and the burn-out and the particle burn-out equation. The influence of the coal particle mass on the pressure in the volume after the mixture burn out and on the burn-out time has been investigated. It has been shown that the burning rate of the coal-dust methane air mixtures depends on the coal particle size. (paper)

Battling coal and rock dust in mines. Bor'ba s ugol'noi i porodnoi pyl'yu v shakhtakh

Energy Technology Data Exchange (ETDEWEB)

Petrukhin, P.M.; Grodel, G.S.; Korenev, A.P.; Krivokhizha, B.M.; Kul' bachnyi, A.N.; Lyubimova, A.I.; Medvedev, E.N.; Yaremachenko, P.P.; Zhilyaev, N.I.

1981-01-01

The problems of comprehensive removal of dust from the atmosphere in mines are discussed. Physical and pnysicochemical properties of mine dust are described, which are important for estimating the processes of its formation, spread, and suppression. Presented are the results of theoretical and natural studies of dust aerodynamics of mines. Modern methods for battling coal and rock dust in mines, as well as means of monitoring the dust level of the air are outlined. Technical descriptions are given for new instruments for changing the dust level of the air. Brief reports are given on the preliminary wetting of coal in the massif, and theoretical and practical problems are discussed concerning hydrological methods of dust removal, dust suppression by foam, and dust trapping during the operation of mining equipment, and also on removal of dust from the air at the surface complex of a mine.

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

Possibility of Coal Combustion Product Conditioning