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Sample records for assessing coal combustion

  1. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Senior, C.L.; Panagiotou, T.; Huggins, F.E.; Huffman, G.P.; Yap, N.; Wendt, J.O.L.; Seames, W.; Ames, M.R.; Sarofim, A.F.; Lighty, J.; Kolker, A.; Finkelman, R.; Palmer, C.A.; Mroczkowsky, S.J.; Helble, J.J.; Mamani-Paco, R.

    1999-07-30

    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 Federal Energy Technology Center (FETC), 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). This report covers the period from 1 April 1999 to 30 June 1999. During this quarter low temperature ashing and elemental analysis of the three Phase II coals were completed. Results from MIT and USGS are comparable. Plans were made for measurements of loss of trace elements during devolatilization and for single particle combustion studies at the University of Utah. The iodated charcoal trap was tested on coal combustion flue gas and was shown to collect both Hg and Se in from the vapor phase with 100% efficiency. Data from the University of Arizona self-sustained combustor were analyzed from the combustion of three coals: Ohio, Wyodak and Illinois No. 6. Ash size distributions and enrichment factors for selected trace elements were calculated. The correlation between the concentration of the more volatile trace elements in the ash and the

  3. TOXIC SUBSTANCES FROM COAL COMBUSTION A COMPREHENSIVE ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    A KOLKER; AF SAROFIM; CA PALMER; FE HUGGINS; GP HUFFMAN; J LIGHTY; JJ HELBLE; JOL WENDT; MR AMES; N YAP; R FINKELMAN; R. MAMANI-PACO; SJ MROCZKOWSKY; T PANAGIOTOU; W SEAMES

    1999-01-28

    The technical objectives of this project are: (a) To identify the effect of the mode-of-occurrence of toxic elements in coal on the partitioning of these elements among vapor, submicron fume, and fly ash during the combustion of pulverized coal, (b) To identify the mechanisms governing the post-vaporization interaction of toxic elements and major minerals or unburnt char, (c) To determine the effect of combustion environment (i.e., fuel rich or fuel lean) on the partitioning of trace elements among vapor, submicron fume, and fly ash during the combustion of pulverized coal, (d) To model the partitioning of toxic elements among various chemical species in the vapor phase and between the vapor phase and complex aluminosilicate melts, (e) To develop the new Toxics Partitioning Engineering Model (ToPEM), applicable to all combustion conditions including new fuels and coal blends, low-NO{sub x} combustion systems, and new power generation plants. A description of the work plan for accomplishing these objectives is presented in Section 2.1 of this report. The work discussed in this report covers the reporting period from 1 October 1998 to 31 December 1998. During this quarter, basic coal testing at USGS was completed. Total sulfur contents range from 0.43 wt-% in the Wyodak to 2.68 wt-% in the Ohio sample. In the North Dakota and Ohio samples, about half of the total sulfur is pyritic and half is organic. The North Dakota sample also contains a minor amount of sulfate, consistent with the presence of barite in this sample. In the Wyodak sample, the majority of the sulfur is organic. Preliminary mineralogy of the three Phase II coals was determined by SEM/EDX. The Ohio coal contains all of the five most common major phases: quartz, illitic clay, kaolinitic clay, pyrite and calcite. Based on this preliminary work, the North Dakota sample appears to lack both kaolinite and calcite, and the Wyodak sample appears to lack calcite. Subsequent SEM work will attempt to reconfirm

  4. 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

  5. Coal combustion products

    Science.gov (United States)

    Kalyoncu, R.S.; Olson, D.W.

    2001-01-01

    Coal-burning powerplants, which supply more than half of U.S. electricity, also generate coal combustion products, which can be both a resource and a disposal problem. The U.S. Geological Survey collaborates with the American Coal Ash Association in preparing its annual report on coal combustion products. This Fact Sheet answers questions about present and potential uses of coal combustion products.

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

    Science.gov (United States)

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

  7. Coal Combustion Science

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. (ed.); Fletcher, T.H.; Hurt, R.H.; Baxter, L.L. (Sandia National Labs., Livermore, CA (United States))

    1991-08-01

    The objective of this activity is to support the Office of Fossil Energy in executing research on coal combustion science. This activity consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency Coal Combustion Science Project. Specific tasks for this activity include: (1) coal devolatilization - the objective of this risk is to characterize the physical and chemical processes that constitute the early devolatilization phase of coal combustion as a function of coal type, heating rate, particle size and temperature, and gas phase temperature and oxidizer concentration; (2) coal char combustion -the objective of this task is to characterize the physical and chemical processes involved during coal char combustion as a function of coal type, particle size and temperature, and gas phase temperature and oxygen concentration; (3) fate of mineral matter during coal combustion - the objective of this task is to establish a quantitative understanding of the mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distribution of mineral species in the unreacted coal, and the local gas temperature and composition.

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

    Energy Technology Data Exchange (ETDEWEB)

    C.L. Senior; T. Panagiotou; F.E. Huggins; G.P. Huffman; N. Yap; J.O.L. Wendt; W. Seames; M.R. Ames; A.F Sarofim; J. Lighty; A. Kolker; R. Finkelman; C.A. Palmer; S.J. Mroczkowsky; J.J. Helble; R. Mamani-Paco

    1999-11-01

    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 Federal Energy Technology Center (FETC), 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). This report covers the reporting period from 1 July 1999 to 30 September 1999. During this period the MIT INAA procedures were revised to improve the quality of the analytical results. Two steps have been taken to reduce the analytical errors. A new nitric acid leaching procedure, modified from ASTM procedure D2492, section 7.3.1 for determination of pyritic sulfur, was developed by USGS and validated. To date, analytical results have been returned for all but the last complete round of the four-step leaching procedure. USGS analysts in Denver have halted development of the cold vapor atomic fluorescence technique for mercury analysis procedure in favor of a new direct analyzer for Hg that the USGS is in the process of acquiring. Since early June, emphasis at USGS has been placed on microanalysis of clay minerals in project coals in

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-08-17

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

  10. Fluidized coal combustion

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L.

    1979-01-01

    Fluidized-bed coal combustion process, in which pulverized coal and limestone are burned in presence of forced air, may lead to efficient, reliable boilers with low sulfur dioxide and nitrogen dioxide emissions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-05-01

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

  12. Assessing coal burnout

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, A. [Pacific Power, Sydney, NSW (Australia)

    1999-11-01

    Recent research has allowed a quantitative description of the basic process of burnout for pulverized coals to be made. The Cooperative Research Centre for Black Coal Utilization has built on this work to develop a coal combustion model which will allow plant engineers and coal company representatives to assess their coals for combustion performance. The paper describes the model and its validation and outlines how it is run. 2 figs.

  13. Coal combustion research

    Energy Technology Data Exchange (ETDEWEB)

    Daw, C.S.

    1996-06-01

    This section describes research and development related to coal combustion being performed for the Fossil Energy Program under the direction of the Morgantown Energy Technology Center. The key activity involves the application of chaos theory for the diagnosis and control of fossil energy processes.

  14. Assessing the Role of Particles in Radiative Heat Transfer during Oxy-Combustion of Coal and Biomass Blends

    Directory of Open Access Journals (Sweden)

    Gautham Krishnamoorthy

    2015-01-01

    Full Text Available This study assesses the required fidelities in modeling particle radiative properties and particle size distributions (PSDs of combusting particles in Computational Fluid Dynamics (CFD investigations of radiative heat transfer during oxy-combustion of coal and biomass blends. Simulations of air and oxy-combustion of coal/biomass blends in a 0.5 MW combustion test facility were carried out and compared against recent measurements of incident radiative fluxes. The prediction variations to the combusting particle radiative properties, particle swelling during devolatilization, scattering phase function, biomass devolatilization models, and the resolution (diameter intervals employed in the fuel PSD were assessed. While the wall incident radiative flux predictions compared reasonably well with the experimental measurements, accounting for the variations in the fuel, char and ash radiative properties were deemed to be important as they strongly influenced the incident radiative fluxes and the temperature predictions in these strongly radiating flames. In addition, particle swelling and the diameter intervals also influenced the incident radiative fluxes primarily by impacting the particle extinction coefficients. This study highlights the necessity for careful selection of particle radiative property, and diameter interval parameters and the need for fuel fragmentation models to adequately predict the fly ash PSD in CFD simulations of coal/biomass combustion.

  15. Nanominerals, fullerene aggregates, and hazardous elements in coal and coal combustion-generated aerosols: An environmental and toxicological assessment.

    Science.gov (United States)

    Saikia, Jyotilima; Narzary, Bardwi; Roy, Sonali; Bordoloi, Manobjyoti; Saikia, Prasenjit; Saikia, Binoy K

    2016-12-01

    Studies on coal-derived nanoparticles as well as nano-minerals are important in the context of the human health and the environment. The coal combustion-generated aerosols also affect human health and environmental quality aspects in any coal-fired station. In this study, the feed coals and their combustion-generated aerosols from coal-fired boilers of two tea industry facilities were investigated for the presence of nanoparticles/nano minerals, fullerene aggregates, and potentially hazardous elements (PHEs). The samples were characterized by using X-ray diffraction (XRD), Time-of-flight secondary ion mass spectroscopy (TOF-SIMS), High resolution-transmission electron microscopy/energy dispersive spectroscopy (HR-TEM/EDS) and Ultra Violet-visible spectroscopy (UV-Vis) to know their extent of environmental risks to the human health when present in coals and aerosols. The feed coals contain mainly clay minerals, whilst glass fragments, spinel, quartz, and other minerals occur in lesser quantities. The PM samples contain potentially hazardous elements (PHEs) like As, Pb, Cd and Hg. Enrichment factor of the trace elements in particulate matters (PMs) was calculated to determine their sources. The aerosol samples were also found to contain nanomaterials and ultrafine particles. The fullerene aggregates along with potentially hazardous elements were also detected in the aerosol samples. The cytotoxicity studies on the coal combustion-generated PM samples show their potential risk to the human health. This detailed investigation on the inter-relationship between the feed coals and their aerosol chemistry will be useful for understanding the extent of environmental hazards and related human health risk.

  16. Coal char fragmentation during pulverized coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L.

    1995-07-01

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

  17. TOXIC SUBSTANCES FROM COAL COMBUSTION--A COMPREHENSIVE ASSESSMENT, PHASE II: ELEMENT MODES OF OCCURRENCE FOR THE OHIO 5/6/7, WYODAK AND NORTH DAKOTA COAL SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Allan Kolker; Stanley J. Mroczkowski; Curtis A. Palmer; Kristen O. Dennen; Robert B. Finkelman; John H. Bullock Jr.

    2002-05-30

    This study reports on the second phase (Phase II) of USGS research activities in support of DOE contract DE-AC22-95PC95101 ''Toxic Substances From Coal Combustion--A Comprehensive Assessment'', funded under DOE Interagency Agreement DE-AI22-95PC95145. The purpose of the study was to provide a quantitative and semi-quantitative characterization of the modes of occurrence of trace elements in coal samples investigated under Phase II, including (1) Ohio 5/6/7, an Ohio bituminous coal sample blended from the No.5, No.6, and No.7 beds; (2) North Dakota, a lignite sample from the Falkirk Mine, Underwood, ND, and (3) Wyodak, a sub-bituminous coal sample from the Cordero Mine, Gillette, WY. Samples from these coal beds were selected for their range in rank and commercial applicability. Results of this research provide basic information on the distribution of elements in Phase II coal samples, information needed for development of a commercial predictive model for trace-element behavior during coal combustion.

  18. Oxy-coal Combustion Studies

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-06

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

  19. Basic theory research of coal spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    WANG Ji-ren; SUN Yan-qiu; ZHAO Qing-fu; DENG Cun-bao; DENG Han-zhong

    2008-01-01

    Discussed latest research results of basic theory research of coal spontaneous combustion in detail, with quantum chemical theory and method and experiment systematically studied chemical structure of coal molecule, adsorption mechanism of coal surface to oxygen molecule and chemical reaction mechanism and process of spontaneous combustion of organic macromolecule and low molecular weight compound in coal from microcosmic view, and established complete theoretical system of the mechanism of coal spontaneous combustion.

  20. Oxy Coal Combustion at the US EPA

    Science.gov (United States)

    Oxygen enriched coal (oxy-coal) combustion is a developing, and potentially a strategically key technology intended to accommodate direct CO2 recovery and sequestration. Oxy-coal combustion is also intended for retrofit application to existing power plants. During oxy-coal comb...

  1. Nitrogen release during coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L.; Mitchell, R.E.; Fletcher, T.H.; Hurt, R.H.

    1995-02-01

    Experiments in entrained flow reactors at combustion temperatures are performed to resolve the rank dependence of nitrogen release on an elemental basis for a suite of 15 U.S. coals ranging from lignite to low-volatile bituminous. Data were obtained as a function of particle conversion, with overall mass loss up to 99% on a dry, ash-free basis. Nitrogen release rates are presented relative to both carbon loss and overall mass loss. During devolatilization, fractional nitrogen release from low-rank coals is much slower than fractional mass release and noticeably slower than fractional carbon release. As coal rank increases, fractional nitrogen release rate relative to that of carbon and mass increases, with fractional nitrogen release rates exceeding fractional mass and fractional carbon release rates during devolatilization for high-rank (low-volatile bituminous) coals. At the onset of combustion, nitrogen release rates increase significantly. For all coals investigated, cumulative fractional nitrogen loss rates relative to those of mass and carbon passes through a maximum during the earliest stages of oxidation. The mechanism for generating this maximum is postulated to involve nascent thermal rupture of nitrogen-containing compounds and possible preferential oxidation of nitrogen sites. During later stages of oxidation, the cumulative fractional loss of nitrogen approaches that of carbon for all coals. Changes in the relative release rates of nitrogen compared to those of both overall mass and carbon during all stages of combustion are attributed to a combination of the chemical structure of coals, temperature histories during combustion, and char chemistry.

  2. 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.

  3. TOXIC SUBSTANCES FROM COAL COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    A KOLKER; AF SAROFIM; CL SENIOR; FE HUGGINS; GP HUFFMAN; I OLMEZ; J LIGHTY; JOL WENDT; JOSEPH J HELBLE; MR AMES; N YAP; R FINKELMAN; T PANAGIOTOU; W SEAMES

    1998-12-08

    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 Federal Energy Technology Center (FETC), the Electric Power Research Institute, the Lignite Research Council, 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-NO combustion systems, and new power generation x plants. Development of ToPEM will be based on PSI's existing Engineering Model for Ash Formation (EMAF). This report covers the reporting period from 1 July 1998 through 30 September 1998. During this period distribution of all three Phase II coals was completed. Standard analyses for the whole coal samples were also completed. Mössbauer analysis of all project coals and fractions received to date has been completed in order to obtain details of the iron mineralogy. The analyses of arsenic XAFS data for two of the project coals and for some high arsenic coals have been completed. Duplicate splits of the Ohio 5,6,7 and North Dakota lignite samples were taken through all four steps of the selective leaching procedure. Leaching analysis of the Wyodak coal has recently commenced. Preparation of polished coal/epoxy pellets for probe/SEM studies is underway. Some exploratory mercury LIII XAFS work was

  4. 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

  5. Atmospheric fluidized-bed combustion (AFBC) co-firing of coal and hospital waste. Environmental Assessment

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    The proposed project involves co-firing of coal and medical waste (including infectious medical waste) in an atmospheric fluidized-bed combustor (AFBC) to safely dispose of medical waste and produce steam for hospital needs. Combustion at the design temperature and residence time (duration) in the AFBC has been proven to render infectious medical waste free of disease producing organisms. The project would be located at the Veterans Affairs (VA) Medical Center in Lebanon, Pennsylvania. The estimated cost of the proposed AFBC facility is nearly $4 million. It would be jointly funded by DOE, Veterans Affairs, and Donlee Technologies, Inc., of York, Pennsylvania, under a cooperative agreement between DOE and Donlee. Under the terms of this agreement, $3.708 million in cost-shared financial assistance would be jointly provided by DOE and the Veterans Affairs (50/50), with $278,000 provided by Donlee. The purposes of the proposed project are to: (1) provide the VA Medical Center and the Good Samaritan Hospital (GSH), also of Lebanon, Pennsylvania, with a solution for disposal of their medical waste; and (2) demonstrate that a new coal-burning technology can safely incinerate infectious medical waste, produce steam to meet hospital needs, and comply with environmental regulations.

  6. Relationship Between Coal Powder and Its Combustibility

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Coal's volatile component,ash and fixed carbon content have different functions in different stages of a combustion process, but the traditional coal classification can precisely show its combustion property.In this experiment coal's evaluation indexes (ignition index Di),(burn off index Df) were used to qualitatively show the ignition property and combustion ending property of coal samples.Meanwhile,considering actual heating circumstances in calciner (in cement plants),this thesis established the relationship among the ignition index,burn off index and coal's industrial analysis value, which makes it possible for the user to predict the quality of coal before using it and is very valuable in practice.

  7. Fluidized bed coal combustion reactor

    Science.gov (United States)

    Moynihan, P. I.; Young, D. L. (Inventor)

    1981-01-01

    A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

  8. Microwave plasma combustion of coal

    Energy Technology Data Exchange (ETDEWEB)

    P.M. Kanilo; V.I. Kazantsev; N.I. Rasyuk; K. Schuenemann; D.M. Vavriv [Institute of Machine Building Problems of the National Academy of Sciences of Ukraine, Kharkov (Ukraine)

    2003-01-01

    Microwave plasma is studied as an alternative to oil or gas fuel for ignition and stabilisation of burning of lean coal. The study is performed on an experimental set-up, which includes a burner with a microwave plasma generator, coal and air supply systems, and measurement equipment. Power and thermochemical characteristics of the coal-plasma interaction have been measured and analysed. The obtained results indicate an essential intensification of ignition and combustion processes in the microwave burner compared to those in conventional burners. In particular, it has been demonstrated that the microwave energy consumption is only about 10% of the required expenditure of oil or gas, measured in heat equivalent. A design of an industrial microwave-plasma burner is proposed. Prospects of such burner for applications at industrial boilers of power plants are discussed. 6 refs., 4 figs., 2 tabs.

  9. Study of mechanically activated coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Anatolij P. Burdukov; Vitalij A. Popov; Valentin A. Faleev [Institute of Thermophysics, Novosibirsk (Russian Federation)

    2009-07-01

    Combustion and air gasification of mechanically activated micro-ground coals in the flux have been studied. Influence of mechanically activated methods of coal grinding on their chemical activity at combustion and gasification has been determined. Intense mechanical activation of coals increases their chemical activity that enables development of new highly boosted processing methods for coals with various levels of metamorphism. 10 refs., 14 figs., 1 tab.

  10. A systems approach to risk assessment: Application to methylmercury from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Saroff, L. [Dept. of Energy, Washington, DC (United States); Lipfert, F.W.; Moskowitz, P.D. [Brookhaven National Lab., Upton, NY (United States)

    1995-01-01

    The Department of Energy (DOE) asked Brookhaven National Laboratory (BNL) to perform a probabilistic assessment of the health risks associated with Hg from coal-fired power plants. The objective of the assessment is to estimate the incremental health risks that might ensue from a typical coal-fired power plant, together with their uncertainties, taking into account existing background levels and the actual adverse health effects that have previously been associated with exposure to various Hg species. Mercury has a long history of association with adverse neurological effects at high exposure levels. The most important current exposure pathway has been found to be ingestion of fish containing methylmercury (MeHg), which is the end product of bioconcentration moving up the aquatic food chain. Mercury can enter natural waters from either industrial discharges or from atmospheric deposition of various inorganic Ho. compounds. Because of the worldwide background and the existence of local emissions sources, Hg deposition must be considered on local, regional and global scales. The regulatory technical challenge presented by methy1mercury is to protect public health without foreclosing an appreciable a portion of the food supply or impacting on the lifestyles of North American native populations. This paper presents an abbreviated account of the DOE/BNL risk assessment, as viewed from a systems perspective. We review the structure of the model, the sources of data used, the assumptions that were made, and the interpretation of the findings. Since publication of the first risk assessment report, we have refined our estimates of local atmospheric dispersion and deposition and {open_quotes}calibrated{close_quotes} the pharmacokinetic portion of the model against observations.

  11. Environmental and socio-economic assessment of co-combustion of coal, biomass and non-hazardous wastes in a full scale power plant

    Energy Technology Data Exchange (ETDEWEB)

    Morais, J.; N. Lapa, N.; Barbosa, R.; Santos, A.; Mendes, B.; Oliveira, J.F. Santos [Environmental Biotechnology Researching, Faculty of Science and Technology, New University of Lisboa (Portugal)

    2008-07-01

    A European project (COPOWER) was developed to assess the possibility to partially replace the coal used in a 243 MWth Power Plant by biomass and non-toxic wastes for the production of electricity. Three combustion scenarios were studied, based on the combustion tests performed at the Stadtwerke Duisburg Power Plant: Scenario 0 (Sc0) - combustion of coal; Scenario 1 (Sc1) - combustion of coal + Sewage Sludge (SS) + Meat and Bone Meal (MBM); Scenario 2 (Sc2) - coal + SS + Wood Pellets (WP). A socio-economic and environmental assessment was performed. In the environmental point of view, Sc0 was the worst scenario, mainly due to the emission of greenhouse gases (GHG). Sc1 was the best scenario, mainly due to the reduction on the GHG emission, substances that contribute for eutrophication and ozone depletion gases. In the socio-economic point of view, Sc0 was the worst scenario, mainly due to the absence of GHG abatement, and Sc1 was the best scenario due to the best cost of the electricity production and negative cost of avoided emissions.

  12. Assessing coal combustion and sourcing strategies using EPRI`s CQIM{sup {trademark}}

    Energy Technology Data Exchange (ETDEWEB)

    Stallard, G.S.; Jennison, K.D. [Black & Veatch, Overland Park, KS (United States)

    1995-12-01

    Understanding the cost and performance issues associated with coal quality or, more precisely, specific constituents within coal is an important ingredient of engineering and planning processes. Such processes can cover a wide range of activities, including how to most cost-effectively burn local coal supplies, how to identify what technologies or designs should be employed for new facilities, and how to identify potentially viable {open_quotes}new{close_quotes} coal supplies. Selection of coals, coal blends, or coal benefication processes is a complex problem. Similarly, it is difficult for industry participants (ministries, regulators, distribution companies, etc.) To correlate fuel selection strategies to overall power system performance costs. The underlying need to understand coal quality impacts on the financial efficiency of a plant is increasingly important in light of economic and environmental pressures faced by today`s power industry. The Coal Quality Impact Model (CQIM{reg_sign}) offers an ideal platform for understanding and evaluating coal quality impacts. Developed by Black & Veatch for the electric Power Research Institute (EPRI), CQIM is a computer {open_quotes}tool{close_quotes} that is dedicated to maintaining state-of-the-art status by continually incorporating the latest technologies or modeling techniques as they become available. By taking advantage of research efforts and a sound engineering modeling approach, the CQIM is capable of predicting plant-wide performance impacts and translating them into costs.

  13. Study on combustion characteristics of blended coals

    Energy Technology Data Exchange (ETDEWEB)

    Li Yonghua; Wang Chunbo; Chen Hongwei [North China Electric Power University, Baoding (China)

    2007-02-15

    Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons. So it is of great necessity to investigate the combustion of blended coals. Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system, characteristics such as burnout, slag, and pollution of some blended coals were investigated. The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced. The results show that the blending of coal has some effect on NOx but there is no obvious rule. SOx emission can be reduced by blending low sulfur coal.

  14. Measurement and simulation of swirling coal combustion

    Institute of Scientific and Technical Information of China (English)

    Liyuan Hu; Lixing Zhou; Yonghao Luo; Caisong Xu

    2013-01-01

    Particle image velocimetry (PIV),thermocouples and flue gas analyzer are used to study swirling coal combustion and NO formation under different secondary-air ratios.Eulerian-Lagrangian large-eddy simulation (LES) using the Smagorinsky-Lilly sub-grid scale stress model,presumed-PDF fast chemistry and eddy-break-up (EBU) gas combustion models,particle devolatilization and particle combustion models,are simultaneously used to simulate swirling coal combustion.Statistical LES results are validated by measurement results.Instantaneous LES results show that the coherent structures for swirling coal combustion are stronger than those for swirling gas combustion.Particles are shown to concentrate along the periphery of the coherent structures.Combustion flame is located in the high vorticity and high particle concentration zones.Measurement shows that secondary-air ratios have little effect on final NO formation at the exit of the combustor.

  15. An assessment of adult risks of paresthesia due to mercury from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Lipfert, F.W.; Moskowitz, P.D.; Fthenakis, V.; Dephillips, M.; Viren, J.; Saroff, L. [Brookhaven National Laboratory, Upton, NY (United States). Dept. of Applied Science

    1995-02-01

    This paper presents a probabilistic assessment of the risks of transient adult paresthesia (tingling of the extremities) resulting from ingestion of methylmercury (MeHg) in fish and shellfish. Two scenarios are evaluated: the baseline, in which the MeHg dose results from the combined effects of eating canned tuna fish, various marine seafood, and freshwater sportfish, and an impact scenario in which the Hg content of the freshwater sportfish is increased due to local deposition from a hypothetical 1000 Mw{sub e} coal-fired power plant. Measurements from the literature are used to establish the parameters of the baseline, including atmospheric rates of Hg deposition and the distributions of MeHg in fish. The Hg intake for the impact scenario is then based on linear scaling of the additional annual Hg deposition as estimated from a Guassian plume dispersion model. Human health responses are based on a logistic fit to the frequencies of paresthesia observed during a grain poisoning incident in Iraq 1971-2. Based on a background prevalence rate of 2.2% for adult paresthesia, the assessment predicts a 5% chance that the increase in paresthesia prevalence due to either baseline or incremental MeHg doses might approach about 1% of the background prevalence rate. 15 refs., 3 figs., 3 tabs.

  16. Recycling of coal combustion wastes.

    Science.gov (United States)

    Oz, Derya; Koca, Sabina; Koca, Huseyin

    2009-05-01

    The separation of unburned carbon from coal-fired power plant bottom ashes was conducted in order to increase the possibility of the recycling of coal combustion wastes. A two-stage flotation technique was used for this study. In the rougher flotation experiments the amounts of collector, dispersant and frother, pulp density, pH, particle size distribution, flotation time and flotation temperature were tested as variables. After rougher flotation experiments, at optimum conditions, the carbon content of the concentrate increased from 13.85 to 51.54% at a carbon recovery of 54.54%. Under the same conditions, the carbon content was reduced to 4.54% at a weight yield of over 80% in the tailings fraction. This fraction meets the industrial specifications and can be utilized as a cement additive. After the cleaner flotation experiment the carbon content of the product was enhanced to 64.81% with a 52.16% carbon recovery. This fraction can be blended back into the coal feed to the power plant boilers.

  17. Coal Combustion Science quarterly progress report, April--June 1990

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. (ed.); Baxter, L.L.; Fletcher, T.H.; Mitchell, R.E.

    1990-11-01

    This document provides a quarterly status report of the Coal Combustion Science Program that is being conducted at the Combustion, Research Facility, Sandia National Laboratories, Livermore, California. Coal devolatilization, coal char combustion, and fate of mineral matter during coal combustion. 56 refs., 25 figs., 13 tabs.

  18. SPONTANEOUS COAL COMBUSTION; MECHANISMS AND PREDICTION.

    Science.gov (United States)

    Herring, James R.; Rich, Fredrick J.

    1983-01-01

    Spontaneous ignition and combustion of coal is a major problem to the coal mining, shipping, and use industries; unintentional combustion causes loss of the resource as well as jeopardy to life and property. The hazard to life is especially acute in the case of underground coal mine fires that start by spontaneous ignition. It is the intention of this research to examine previously suggested causes of spontaneous ignition, to consider new evidence, and to suggest an experimental approach to determine which of these suggested causes is relevant to western U. S. coal. This discussion focuses only on causes and mechanism of spontaneous ignition.

  19. Combustion of Coal/Oil/Water Slurries

    Science.gov (United States)

    Kushida, R. O.

    1982-01-01

    Proposed test setup would measure combustion performance of new fuels by rapidly heating a droplet of coal/oil/water mixture and recording resulting explosion. Such mixtures are being considered as petroleum substitutes in oil-fired furnaces.

  20. 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)

  1. Coal Combustion Products Extension Program

    Energy Technology Data Exchange (ETDEWEB)

    Tarunjit S. Butalia; William E. Wolfe

    2006-01-11

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

  2. Isotopic signature of atmospheric phosphate emitted from coal combustion

    Science.gov (United States)

    Weinberger, Roi; Weiner, Tal; Angert, Alon

    2016-07-01

    Atmospheric deposition of phosphorus (P) serves as an important nutrient input for many terrestrial, marine and freshwater ecosystems, influencing their biogeochemistry and primary production. Fossil fuel combustion, principally coal, is estimated to be a major source of atmospheric-P in industrialized regions. In this research, we aim to find a distinct isotopic signature for fly coal ash, the by-product of coal combustion that is emitted to the atmosphere. This signature could be used to identify coal's contribution to atmospheric-P. For this aim, ten fly coal ash samples from different coal sources, collected by power station filters, were analyzed for P concentrations and stable oxygen isotopic composition (δ18OP). Two inorganic phosphate fractions were analyzed: HCl-extractable and resin-extractable (bioavailable P). High HCl-P concentrations of up to 3500 μg P/g ash were found with a distinct δ18OP range of 17.1-20.5‰. The resin-P concentrations were substantially lower (biosphere since these combustion products likely acidify in the atmosphere to become bioavailable. This is also supported by our finding that smaller particles, which are more indicative of the particles actually emitted to the atmosphere, are significantly P-richer. Natural dust sources' δ18OP overlap fly ash's range, complicating the assessment of coal's contribution. Nonetheless, our results provide a new tool for identification of fossil fuel combustion sources in local and global atmospheric P deposition.

  3. STUDY ON MAJOR FACTORS INFLUENCING SPONTANEOUS COMBUSTION OF COAL

    Institute of Scientific and Technical Information of China (English)

    Deng Jun; Xu Jingcai; Zhang Xinghai

    2000-01-01

    This paper theoretically analyzes major factors influencing spontaneous combustion of coal, such as molecule structure of coal, porosity, temperature, concentration of oxygen, coal thickness, velocity of face advance, and so on; and probes into how they affect the process of spontaneous combustion of coal, which is of momentous significance to predict or control self-ignition of coal.

  4. Health impacts of domestic coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Finkelman, R.B.

    1999-07-01

    The US Environmental Protection Agency (EPA) has concluded that, with the possible exception of mercury, there is no compelling evidence to indicate that emissions from coal-burning electric utility generators cause human health problems. The absence of detectable health problems is in part due to the fact that the coals burned in the US generally contain low to modest concentrations of potentially toxic trace elements and that many coal-burning utilities employ sophisticated pollution control systems that efficiently reduce the emissions of hazardous elements. This is not so in many developing countries, especially in homes where coal is used for heating and cooking. Domestic use of coal can present serious human health problems because the coals are generally mined locally with little regard to their composition and the coals are commonly burned in poorly vented or unvented stoves directly exposing residents to the emissions. In China alone several hundred million people commonly burn raw coal in unvented stoves that permeate their homes with high levels of toxic metals and organic compounds. At least 3,000 people in Guizhou Province in southwest China are suffering from severe arsenic poisoning. The primary source of the arsenic appears to be consumption of chili peppers dried over fires fueled with high-arsenic coal. Coal's in the region contain up to 35,000 ppm arsenic. Chili peppers dried over these high-arsenic coal fires absorb 500 ppm arsenic on average. More than 10 million people in Guizhou Province and surrounding areas suffer from dental and skeletal fluorosis. The excess fluorine is due to eating corn dried over burning briquettes made from high-fluorine coals and high-fluoring clay binders. Polycyclic aromatic hydrocarbons formed during coal combustion are believed to cause or contribute to the high incidence of esophageal and lung cancers in parts of China. Domestic coal combustion has also caused selenium poisoning and possibly mercury

  5. Study on combustion characteristics of blended coals

    Institute of Scientific and Technical Information of China (English)

    LI Yonghua; WANG Chunbo; CHEN Hongwei

    2007-01-01

    Power plants in China have to burn blended coal instead of one specific coal for a variety of reasons.So it is of great necessity to investigate the combustion of blended coals.Using a test rig with a capacity of 640 MJ/h with an absolute milling system and flue gas online analysis system,characteristics such as burnout,slag,and pollution of some blended coals were investigated.The ratio of coke and slag as a method of distinguishing coal slagging characteristic was introduced.The results show that the blending of coal has some effect on NOx but there is no obvious rule.SOx emission can be reduced by blending low sulfur coal.

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

    OpenAIRE

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

    2015-01-01

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

  7. Assessment of Research Needs for Coal Utilization

    Energy Technology Data Exchange (ETDEWEB)

    Penner, S.S.

    1983-08-01

    The Coal Combustion and Applications Working Group (CCAWG), at the request of J.W. Mares (Assistant Secretary for Fossil Energy) and A.W. Trivelpiece (Director, Office of Energy Research), has reviewed and evaluated the U.S. programs on coal combustion and utilization. The important topical areas of coal gasification and coal liquefaction have been deliberately excluded because R and D needs for these technologies were reviewed previously by the DOE Fossil Energy Research Working Group. The CCAWG studies were performed in order to provide an independent assessment of research areas that affect prospects for augmented coal utilization. In this report, we summarize the findings and research recommendations of CCAWG.

  8. USGS TOXIC SUBSTANCES FROM COAL COMBUSTION -- FORMS OF OCCURRENCE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Allan Kolker; Stanley J. Mroczkowski; Curtis A. Palmer; Robert B. Finkelman

    1999-04-01

    Detailed information on trace-element modes of occurrence in coal is essential to understanding and predicting trace-element transformations taking place during coal combustion. The USGS has developed quantitative and semi-quantitative methods for determining the mode of occurrence of trace elements in coal. This information is needed to generate predictive models for trace-element behavior, the ultimate goal of DOE contract DE-AC22-95PC95101 ``Toxic Substances From Coal Combustion--A Comprehensive Assessment'' awarded to PSI, Inc. USGS activities in support of this contract have a direct bearing on the predictive equations being developed as the primary product of the PSI program.

  9. 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...

  10. Combustion char morphology related to combustion temperature and coal petrography

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, P.; Petersen, H.I.; Thomsen, E. [Geological Survey of Denmark, Copenhagen (Denmark)

    1996-07-01

    Chars produced from different reactors were found to lack consistency of morphological charactersitics. Therefore, the morphology of chars sampled from various laboratory-scale reactors operating at temperatures from 800 to {gt} 1400{degree}C, together with chars collected directly in the flame zone in a full-scale pulverised fuel combustion experiment, was examined. A coal and coal blend dominated by vitrinite-rich microlithotypes together with four coals dominated by inertinite-rich microlithotypes were used to produce the combustion chars. Char samples produced at temperatures above {approximately} 1300{degree}C have a morphotype composition very similar to the composition of the full-scale char samples, whereas the morphotype compositions of those produced at {approximately} 1550{degree}C or lower are significantly different. Correlation between coal petrography and char morphology and determination of char reactivity should thus be attempted only using chars produced at temperatures comparable with those for the intended use of the coal. A clear distinction between the high-temperature char samples (burnout 50-60wt% daf) emerges which is related mainly to the parent coal petrography and probably secondarily to the rank. Vitrite, clarite and vitrinertie V may be correlated with the porous tenuisphere and crassisphere morphotypes, whereas inertite, durite, vitrinertite I, duroclarite and charodurite may be correlated with the crassinetwork-mixed-network-mixed morphotype group. 29 refs., 7 figs., 7 tabs.

  11. COAL COMBUSTION EFFICIENCY IN CFB BOILER

    Institute of Scientific and Technical Information of China (English)

    Hairui Yang; Guangxi Yue

    2005-01-01

    The carbon content in the fly ash from most Chinese circulating fluidized bed (CFB) boilers is much higher than expected, thus directly influencing the combustion efficiency. In the present paper, carbon burnout was investigated both in field tests and laboratory experiments. The effect of coal property, operation condition, gas-solid mixing, char deactivation,residence time and cyclone performance are analyzed seriatim based on large amount of experimental results.A coal index is proposed to describe the coal rank, defined by the ratio of the volatile content to the coal heat value, is a useful parameter to analyze the char burnout. The carbon content in the fly ash depends on the coal rank strongly. CFB boilers burning anthracite, which has low coal index, usually have high carbon content in the fly ash. On the contrary, the CFB boilers burning brown coal, which has high coal index, normally have low carbon content.Poor gas-solid mixing in the furnace is another important reason of the higher carbon content in the fly ash. Increasing the velocity and rigidity of the secondary air could extend the penetration depth and induce more oxygen into the furnace center. Better gas solid mixing will decrease the lean oxygen core area and increase char combustion efficiency.The fine char particles could be divided into two groups according to their reactivity. One group is "fresh" char particles with high reactivity and certain amount of volatile content. The other group of char particles has experienced sufficient combustion time both in the furnace and in the cyclone, with nearly no volatile. These "old" chars in the fly ash will be deactivated during combustion of large coal particles and have very low carbon reactivity. The generated fine inert char particles by attrition of large coal particles could not easily burn out even with the fly ash recirculation. The fraction of large coal particles in coal feed should be reduced during fuel preparation process.The cyclone

  12. Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix D. Assessment of NO/sub x/ control technology for coal fired utility boilers. [Low-excess-air, staged combustion, flu gas recirculation and burner design

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    An NOx control technology assessment study was conducted to examine the effectiveness of low-excess-air firing, staged combustion, flue gas recirculation, and current burner/boiler designs as applied to coal-fired utility boilers. Significant variations in NOx emissions exist with boiler type, firing method, and coal type, but a relative comparison of emissions control performance, cost, and operational considerations is presented for each method. The study emphasized the numerous operational factors that are of major importance to the user in selecting and implementing a combustion modification technique. Staged combustion and low-excess-air operation were identified as the most cost-effective methods for existing units. Close control of local air/fuel ratios and rigorous combustion equipment maintenance are essential to the success of both methods. Flue gas recirculation is relatively ineffective and has the added concern of tube erosion. More research is needed to resolve potential corrosion concerns with low-NOx operating modes. Low-NOx burners in conjunction with a compartmentalized windbox are capable of meeting a 0.6-lb/million Btu emission level on new units. Advanced burner designs are being developed to meet research emission goals of approximately 0.25 lb/MBtu.

  13. Combustion Characteristics of Polyethylene and Coal Powder at High Temperature

    Institute of Scientific and Technical Information of China (English)

    LONG Shi-gang; CAO Feng; WANG Si-wei; SUN Liu-heng; PANG Jian-ming; SUN Yu-ping

    2008-01-01

    To study the combustion characteristics of the polyethylene (PE) particle and coal powder at blast temperature of the blast furnace, the contents of CO and CO2 of off-gas during the combustion of PE particle and coal powder at the 1 200 ℃ and 1 250 ℃ were measured using carbon monoxide and carbon dioxide infrared analyzer, and then the corresponding combustion ratio was calculated. The results showed that when the temperature is high, the combustion speed of PE and coal powder is high and the corresponding combustion ratio is high. Whereas, the combustion speed and ratio of PE are much higher than those of coal powder.

  14. 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

  15. 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.

  16. Combustion enhancing additives for coal firing

    Energy Technology Data Exchange (ETDEWEB)

    Katherine Le Manquais; Colin Snape; Ian McRobbie; Jim Barker [University of Nottingham, Nottingham (United Kingdom). School of Chemical, Environmental and Mining Engineering (SChEME)

    2007-07-01

    For pulverised fuel (pf) combustion, the level of unburnt carbon in fly ash is now considerably more problematic worldwide than a decade ago, because of the introduction of low NOx burners and the increased level of high inertinite in internationally traded coals. Thus, there is a major opportunity to develop an effective additive to improve carbon burnout and obviate the need for post-treatment of fly ash, which endeavours to meet specifications for filler/building materials applications and thereby avoid landfill. A robust comparison of the reactivity of different coals and their corresponding chars is necessary, in order to estimate the effects of such an additive on pf combustion. Coal chars have been generated on a laboratory scale using thermal gravimetric analysis (TGA) and on a larger scale using a drop tube furnace (DTF), which is more representative of the rapid heating rates and mixing achieved on pf combustion. The TGA results indicate that chars have varying levels of reactivity, dependent on the parent coal properties. When physically mixed with a propriety metal additive, the degree of enhancement to the reactivity of these chars also appeared reliant on the parent coal characteristics. Additionally it was demonstrated that DTF chars, whilst showing similar reactivity trends, are less reactive than the equivalent coal chars produced by the TGA. However, when mixed with the metal additive the DTF chars show a significantly greater improvement in reactivity than their analogous TGA chars, indicating the additive may have the greatest impact on the most unreactive carbon in the coal. 42 refs., 6 figs., 1 tab.

  17. Ash formation under pressurized pulverized coal combustion conditions

    Science.gov (United States)

    Davila Latorre, Aura Cecilia

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

  18. Stabilization of pulverized coal combustion by plasma assist

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-03-01

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

  19. Coal combustion science. Quarterly progress report, July--September 1994

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.; Baxter, L.L.; Davis, K.A.; Hurt, R.H.; Yang, N.Y.C.

    1995-09-01

    This document is a quarterly status report of the Coal Combustion Science Project that is being conducted at the Combustion Research Facility, Sandia National Laboratories, Livermore, California. The information reported is for the period July-September 1994. The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project.

  20. Coal combustion products. A global perspective

    Energy Technology Data Exchange (ETDEWEB)

    Heidrich, Craig [Ash Development Association Australia, Wollongong (Australia); Feuerborn, Hans-Joachim [European Coal Combustion Products Association, Essen (Germany); Weir, Anne [Association of Canadian Industries Recycling Coal Ash (CIRCA), London (Canada)

    2013-07-01

    Large-scale use of coal in power generation gives rise to significant quantities of coal combustion products (CCP) from which important 'hard won' end use markets have been established. Current global CCP production and utilisation including volume and value of international trade will be discussed. An overview of country-specific classification systems for CCPs will be discussed, moreover the important role of legislation in creating legal certainty for the ongoing investment in CCPs management and market development. (orig.)

  1. Coal combustion science. Quarterly progress report, April 1993--June 1993

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.

    1994-05-01

    This document is a quarterly status report of the Coal Combustion Science Project that is being conducted at the Combustion Research Facility, Sandia National Laboratories. The information reported is for Apr-Jun 1993. The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the PETC Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency Coal Combustion Science Project. The objective of the kinetics and mechanisms of pulverized coal char combustion task is to characterize the combustion behavior of selected US coals under conditions relevant to industrial pulverized coal-fired furnaces. Work is being done in four areas: kinetics of heterogeneous fuel particle populations; char combustion kinetics at high carbon conversion; the role of particle structure and the char formation process in combustion and; unification of the Sandia char combustion data base. This data base on the high temperature reactivities of chars from strategic US coals will permit identification of important fuel-specific trends and development of predictive capabilities for advanced coal combustion systems. The objective of the fate of inorganic material during coal combustion task is the establish a quantitative understanding of the mechanisms and rates of transformation, fragmentation, and deposition of inorganic material during coal combustion as a function of coal type, particle size and temperature, the initial forms and distribution of inorganic species in the unreacted coal, and the local gas temperature and composition. In addition, optical diagnostic capabilities are being developed for in situ, real-time detection of inorganic vapor species and surface species during ash deposition. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  2. Combustion velocity of coal in seat of an underground fire

    Energy Technology Data Exchange (ETDEWEB)

    Yanchenko, G.A.; Kuzyaev, L.S.; Serra-Suares, L.Kh.

    1988-02-01

    Using the example of an underground fire in a very long coal channel, analyzes the processes of energy interchange between the gas phase and the coal surface in the channel and explains that calculations to assess the duration of burning (and hence assist in extinguishing or containing the fire) need to be able to account for the speed of transition of the coal from the solid phase (burning mass) to the gaseous phase in conditions of oxygen (in the form of products of complete combustion), reduction and dry distillation (in the form of products of incomplete combustion). Demonstrates in formulaic form the correlation between the mass velocity of the coal burning, the volume velocity of the arrival of air at the seat of the fire, the excess oxidant coefficient and the volume of air which is theoretically required to completely burn 1 kg of coal and presents the coefficients of excess oxygen and a generalized, statistical coefficient averaged for eight basic coal groups in tabular form. 1 ref.

  3. Assessment of an atmospheric fluidized-bed coal-combustion gas-turbine cogeneration system for industrial application

    Energy Technology Data Exchange (ETDEWEB)

    Graves, R. L.; Holcomb, R. S.; Tallackson, J. R.

    1979-10-01

    This study was initiated to provide information on the future potential industrial market for a cogeneration system consisting of a fluidized-bed coal combustor coupled to a gas-turbine (Brayton cycle) power system that uses air as the working fluid. In assessing the potential applications for the system, the process heat energy consumption by industry is identified, with special detail included on the six most energy-intensive industries. The potential impact on the nation's oil and natural gas consumption that would result from wide-spread utilization of coal for process heat is also estimated. The fraction of industrial process heat that the system could feasibly satisfy from a thermodynamic viewpoint is estimated, and the performance (potential fuel efficiency and heat/power ratio) of the atmospheric fluidized-bed gas-turbine system is calculated. Also treated are several specific case studies of industries in which the system could be incorporated. Major parameters are specified, and flow sheets are derived for systems that would satisfy the heat and power requirements of the process or industry. The overall fuel utilization efficiency, thermal power rating, and potential number of installations are specified for these case studies. The findings of the study indicate that there is a sizable potential market for the system, with over 1000 possible installations disclosed after reviewing only 8 specific industries from 6 major Standard Industrial Classification (SIC) groups. The potential displacement of oil and gas by coal in process heating is shown to be about 1.60 m/sup 3//sec (870,000 bbl/d) of oil and 4590 m/sup 3//sec (14.0 billion ft/sup 3//d) of natural gas for all industries combined. Continued development of the fluidized-bed coal combustor and power system is recommended so that this potential may be at least partially realized.

  4. Coal Combustion Products Extension Program

    Energy Technology Data Exchange (ETDEWEB)

    Tarunjit S. Butalia; William E. Wolfe

    2003-12-31

    The primary objective of the CCP Extension Program is to promote the responsible uses of Ohio CCPs that are technically sound, environmentally safe, and commercially competitive. A secondary objective is to assist other CCP generating states (particularly neighboring states) in establishing CCP use programs within their states. The goal of the CCP extension program at OSU is to work with CCP stakeholders to increase the overall CCP state utilization rate to more than 30% by the year 2005. The program aims to increase FGD utilization for Ohio to more than 20% by the year 2005. The increased utilization rates are expected to be achieved through increased use of CCPs for highway, mine reclamation, agricultural, manufacturing, and other civil engineering uses. In order to accomplish these objectives and goals, the highly successful CCP pilot extension program previously in place at the university has been expanded and adopted by the university as a part of its outreach and engagement mission. The extension program is an innovative technology transfer program with multiple sponsors. The program is a collaborative effort between The Ohio State University (College of Engineering and University Extension Service), United States Department of Energy's National Energy Technology Laboratory, Ohio Department of Development's Coal Development Office, and trade associations such as the American Coal Ash Association as well as the Midwest Coal Ash Association. Industry co-sponsors include American Electric Power, Dravo Lime Company, and ISG Resources. Implementation of the proposed project results in both direct and indirect as well as societal benefits. These benefits include (1) increased utilization of CCPs instead of landfilling, (2) development of proper construction and installation procedures, (3) education of regulators, specification-writers, designers, construction contractors, and the public, (4) emphasis on recycling and decrease in the need for landfill

  5. Performance of PAHs emission from bituminous coal combustion

    Institute of Scientific and Technical Information of China (English)

    严建华; 尤孝方; 李晓东; 倪明江; 尹雪峰; 岑可法

    2004-01-01

    Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion.

  6. Combustion and NOx Emission Behavior of Chinese Coals

    Institute of Scientific and Technical Information of China (English)

    CHENHonggang; XIEKechang

    2002-01-01

    Seven Chinese coals ranking from anthracite to sub-bituminous from the Shanxi province were selected for study to forecast the combustion and NOx emission behavior.Three UK,one Indonesia and one South Africa coal was included in the study for reference.A flat flame-turbulent jet apparatus was employed to assess flame stability,ignition performance and NOx emission behavior for the initial stage of devolatilization and combustion. This apparatus can simulate particle heating rates,maximum temperatures and the influence of the turbulent fluid interactionson the fate of volatiles.To simulate processes occurring over longer residence time, additional devolatilization experiments were performed in a drop tube furnace.Char reactivity was studied through thermogravimetric analysis.Finally,fouling propensity was studied with the aid of a purpose-built laboratory combustor that enabled the characteristics of the ash deposit to be assessed empirically.The results show that Chinese coals do not appear to possess unusual features in respect of NOx formation,flame stability and ignition,char burnout and ash slagging.The range of coals available in China appears sufficiently broad that suits all requirements.In particular,Shenfu coal,with its initial fast devolatilization and nitrogen release rates and its low initial nitrogen content and high char reactivity,will perform well when fired in industrial boilers as far as NOx emission,flame stability and combustion efficiency are concerned.Pingshuo coal exhibits high char reactivity and an attractive slagging performance suggesting that this fuel represents a good compromise between NOx emission and overall plant efficiency.

  7. 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.

  8. Organic emissions in coal combustion in relation to coal structure and combustion temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bruinsma, O.S.L.; Verhagen, E.J.H.; Moulijn, J.A.

    1985-10-01

    The pulsed combustion of coal has been studied in a small fluidized-bed reactor. The effect of combustion temperature and coal rank on the organic composition of the off-gas was investigated. Results are presented for the combustion of an anthracite, a medium-volatile bituminous coal and a high-volatile bituminous coal at 700, 800 and 900 C. The analytical techniques used include on-line FT-IR, O2 monitoring, FID and off-line GC-MS using Tenax as adsorbent. About 120 hydrocarbons were found, of which over 80% have been identified. Overall combustion characteristics such as oxygen consumption, total amount of unburned hydrocarbons and swelling properties of the coal have been related to the composition of the organic substances in the off-gas. The distribution of the polycyclic aromatics, from benzene to chrysene, and of alkylated derivatives is discussed in detail. Oxygen-containing compounds have also been analysed, although detailed discussion would be premature. 20 references.

  9. 75 FR 64974 - Notice of Data Availability on Coal Combustion Residual Surface Impoundments

    Science.gov (United States)

    2010-10-21

    ... Coal Combustion Residual Surface Impoundments AGENCY: Environmental Protection Agency (EPA). ACTION... of Coal Combustion Residuals from Electric Utilities. The Agency is seeking public comment on how, if...; Disposal of Coal Combustion Residuals From Electric Utilities Docket, Attention Docket ID No.,...

  10. 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.

  11. OxyFuel combustion of Coal and Biomass

    DEFF Research Database (Denmark)

    Toftegaard, Maja Bøg

    investigations on the combustion of coal, biomass (straw), and blends of coal and straw in air and O2/CO2 mixtures. The experiments have been performed in semi-technical scale in a once-through 30 kWth swirl-stabilized flame. The work has focused on improving the fundamental knowledge on oxyfuel combustion...... the important aspects of ash and deposit formation during co-firing of coal and biomass and combustion of pure biomass in oxyfuel atmospheres in semi-technical scale. The presented work has lead to the identification of reference operating conditions which enables a direct comparison of combustion in air...... and oxyfuel atmospheres. Apart from slightly improved burnout and reduced emissions of NO during oxyfuel combustion these operating conditions yield similar combustion characteristics in both environments. Co-firing coal and biomass or combustion of pure biomass in an oxyfuel power plant could yield...

  12. Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    QI Qing-jie; LIN Zhi-yan; LIU Jian-zhong; WU Xian; ZHOU Jun-hu; CEN Ke-fa

    2008-01-01

    In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermo-dynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention.

  13. Coal Combustion Science. Quarterly progress report, October--December 1994

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.; Baxter, L.L.; Davis, K.A.; Hurt, R.H.; Yang, N.Y.C.

    1996-02-01

    The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project. Specific tasks include: Task 1--Kinetics and mechanisms of pulverized coal char combustion; and Task 2--deposit growth and property development in coal-fired furnaces. The objective of task 1 is to characterize the combustion behavior of selected US coals under conditions relevant to industrial pulverized coal-fired furnaces. Work is being done in four areas: (a) kinetics of heterogeneous fuel particle populations; (b) char combustion kinetics at high carbon conversion; (c) the role of particle structure and the char formation process in combustion and; (d) unification of the Sandia char combustion data base. The objectives of Task 2 are to provide a self-consistent database of simultaneously measured, time-resolved, ash deposit properties in well-controlled and well-defined environments and to provide analytical expressions that relate deposit composition and structure to deposit properties of immediate relevance to PETC`s Combustion 2000 program. The task include the development and use of diagnostics to monitor, in situ and in real time, deposit properties, including information on both the structure and composition of the deposits.

  14. Energy Saving and Pollution Reducing Effects of Coal Combustion Catalysts

    Institute of Scientific and Technical Information of China (English)

    WU Zenghua; YU Zhiwu; ZHU Wentao; ZHOU Rui

    2001-01-01

    Coal catalytic agents (CCS type) have been prepared to improve coal combustion and reduce air pollution.The energy and pollution reductions resulting from the catalysts have been examined with thermal analysis and chromatography.The CCS agents lower the ignition temperature by 30-80℃ and improve the coal combustion efficiency by 10%-25%.The agents also reduce the release of carbon monoxide,sulfur dioxide,and coal particles to environment.The working mechanisms of the catalysts are discussed in terms of their participation in various physico-chemical processes during combustion.

  15. 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...

  16. Effects of pyrite on the spontaneous combustion of coal

    Institute of Scientific and Technical Information of China (English)

    Jun Deng; Xiaofeng Ma; Yutao Zhang; Yaqing Li; Wenwen Zhu

    2015-01-01

    Pyrite has a significant effect on the spontaneous combustion of coal. The presence of pyrite can change the propensity of coal towards spontaneous combustion. The influences of various pyrite contents on the parameters of spontaneous combustion, such as index gases, temperature and released heat etc., were investigated in this study. Coal samples with different pyrite contents (0%, 3%, 5%, 7%and 9%) were made by mixing coal and pyrite. The oxidation experiments under temperature-programmed condition were carried out to test the release rate of gaseous oxidation products at different temperatures. Differential scanning calorimeter (DSC) was employed to measure the intensity of heat release during coal oxidation for various pyrite contents. The results indicate that pyrite can nonlinearly accelerate the process of spontaneous combustion. The coal sample with a pyrite content of 5% has the largest CO release rate and oxygen adsorption as well. However, the coal sample with a pyrite content of 7% has the largest rate of heat flow according to the results from the DSC tests. Pyrite contents of 5%–7% in coal has the most significant effects on spontaneous combustion within the range of this study. The conclusions are conducive to the evaluation and control for the spontaneous combustion of coal.

  17. Enhancement of pulverized coal combustion by plasma technology

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

  18. Desulfurization kinetics of coal combustion gases

    Directory of Open Access Journals (Sweden)

    S.R. Bragança

    2003-06-01

    Full Text Available Desulfurization of the gases from coal combustion was studied, using limestone (marble as the sorbent in a fluidized-bed reactor. The kinetic parameter, k, was measured by analyzing the reduction in SO2 emissions in relation to time when a batch of limestone was introduced directly into the combustor chamber. The influence of sorbent composition and particle size was also studied. The CaO content in the limestone was more important than the MgO content. Sorbent particle size showed a strong influence on the reaction time and efficiency of desulfurization. The results of this work prove that marble type is very important in the choice of sorbent for a desulfurization process. A magnesian limestone showed a better performance than a dolomite. Therefore, the magnesian limestone is more efficient for a shorter particle residence time, which is characteristic of the bubbling fluidized bed.

  19. Desulfurization kinetics of coal combustion gases

    Energy Technology Data Exchange (ETDEWEB)

    Braganca, S.R.; Jablonski, A.; Castellan, J.L. [Universidade Federal Rio Grande do Sul, Porto Alegre (Brazil)

    2003-06-01

    Desulfurization of the gases from coal combustion was studied, using limestone (marble) as the sorbent in a fluidized-bed reactor. The kinetic parameter, k, was measured by analyzing the reduction in SO{sub 2} emissions in relation to time when a batch of limestone was introduced directly into the combustor chamber. The influence of sorbent composition and particle size was also studied. The CaO content in the limestone was more important than the MgO content. Sorbent particle size showed a strong influence on the reaction time and efficiency of desulfurization. The results of this work prove that marble type is very important in the choice of sorbent for a desulfurization process. A magnesian limestone showed a better performance than a dolomite. Therefore, the magnesian limestone is more efficient for a shorter particle residence time, which is characteristic of the bubbling fluidized bed.

  20. Thermally induced structural changes in coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Flagan, R.C.; Gavalas, G.R.

    1992-01-01

    The effects of the temperature-time history during coal devolitization and oxidation on the physical properties and the reactivity of resulting char were studied experimentally for temperatures and residence times typical of pulverized combustion. Experiments were also carried out at somewhat lower temperatures and correspondingly longer residence times. An electrically heated laminar flow reactor was used to generate char and measure the rates of oxidation at gas temperatures about 1600K. Partially oxidized chars were extracted and characterized by gas adsorption and mercury porosimetry, optical and scanning electron microscopy, and oxidation in a thermogravimetric analysis system (TGA). A different series of experiments was conducted using a quadrople electrodynamic balance. Single particles were suspended electrodynamically and heated by an infrared laser in an inert or oxygen-containing atmosphere. During the laser heating, measurements were taken of particle mass, size/shape, and temperature.

  1. Plasma-supported coal combustion in boiler furnace

    Energy Technology Data Exchange (ETDEWEB)

    Askarova, A.S.; Karpenko, E.I.; Lavrishcheva, Y.I.; Messerle, V.E.; Ustimenko, A.B. [Kazakh National University, Alma Ata (Kazakhstan). Dept. of Physics

    2007-12-15

    Plasma activation promotes more effective and environmentally friendly low-rank coal combustion. This paper presents Plasma Fuel Systems that increase the burning efficiency of coal. The systems were tested for fuel oil-free start-up of coal-fired boilers and stabilization of a pulverized-coal flame in power-generating boilers equipped with different types of burners, and burning all types of power-generating coal. Also, numerical modeling results of a plasma thermochemical preparation of pulverized coal for ignition and combustion in the furnace of a utility boiler are discussed in this paper. Two kinetic mathematical models were used in the investigation of the processes of air/fuel mixture plasma activation: ignition and combustion. A I-D kinetic code PLASMA-COAL calculates the concentrations of species, temperatures, and velocities of the treated coal/air mixture in a burner incorporating a plasma source. The I-D simulation results are initial data for the 3-D-modeling of power boiler furnaces by the code FLOREAN. A comprehensive image of plasma-activated coal combustion processes in a furnace of a pulverized-coal-fired boiler was obtained. The advantages of the plasma technology are clearly demonstrated.

  2. Carbon dioxide from coal combustion: Variation with rank of US coal

    Science.gov (United States)

    Quick, J.C.; Glick, D.C.

    2000-01-01

    Carbon dioxide from combustion of US coal systematically varies with ASTM rank indices, allowing the amount of CO2 produced per net unit of energy to be predicted for individual coals. No single predictive equation is applicable to all coals. Accordingly, we provide one equation for coals above high volatile bituminous rank and another for lower rank coals. When applied to public data for commercial coals from western US mines these equations show a 15% variation of kg CO2 (net GJ)-1. This range of variation suggests reduction of US CO2 emissions is possible by prudent selection of coal for combustion. Maceral and mineral content are shown to slightly affect CO2 emissions from US coal. We also suggest that CO2 emissions increased between 6 and 8% in instances where Midwestern US power plants stopped burning local, high-sulfur bituminous coal and started burning low-sulfur, subbituminous C rank coal from the western US.

  3. Effect of oxydesulphurization on the combustion characteristics of coal

    Energy Technology Data Exchange (ETDEWEB)

    Yaman, S.; Kucukbayrak, S. [Technical University of Istanbul, Istanbul (Turkey). Dept. of Chemical Engineering

    1997-06-01

    Desulphurization of a Turkish lignite by oxydesulphurization using dilute alkaline solutions, obtained by the extraction of fly ash with water, was carried out under 0-1.5 MPa partial pressure of oxygen at temperatures between 403 and 498 K for 30-90 min time intervals. The combustion characteristics of original and desulphurized lignite samples are compared using TGA. DTG curves were derived and the effects of desulphurization conditions such as temperature, partial pressure of oxygen and time on coal reactivity were studied. Ignition temperature, maximum combustion rate, combustion period, and the end temperature of combustion were considered. Relations between coal reactivity and removals of sulphur and ash contents were also studied.

  4. Study on Environmental Impact Assessment of Heavy Metals in Coal Combustion Products%电厂燃煤产物中重金属元素的环境影响评价研究

    Institute of Scientific and Technical Information of China (English)

    王馨; 冯启言; 武旭仁; 孟庆俊

    2013-01-01

    Taking coal combustion products from two coal -fired power plants in Shandong as example , the envi-ronmental impact assessment method of heavy metals in coal combustion products was studied .4 heavy metals of As, Cu, Zn, Pb, Hg in raw coal, fly ash,bottom ash of the power plants were determined .The leaching rate of heavy metals in the coal combustion products were determined by immersion test .Atmospheric pollution index, water pollution index were calculated .The results showed that the volatility of the heavy metals in the coal during coal combustion is high.The integrated pollution indices of the heavy metals in the coal from the two plants to at-mospheric environment are 6.83 and 7.93, which belong to heavy pollution indices.The integrated pollution in-dices of heavy metals in the coal -fired products to water environment are 4.35 and 3.38 respectively, belonging to heavy pollution indeces.%  以山东矿区某两个电厂燃煤为例,探讨了燃煤产物中重金属元素的环境影响评价方法。测定了电厂原煤、飞灰、底灰中As、Cu、Zn、Pb这4种重金属元素的含量,通过浸泡实验测得了燃煤产物中重金属元素的浸溶率,计算出了燃煤产物中重金属元素对大气、水环境的污染因子。结果表明,电厂燃煤过程中,重金属元素挥发性较高,两电厂对大气环境的综合污染因子分别为6.83和7.93,污染等级为重污染。对于水环境的综合污染因子为4.35与3.38,也属重污染。

  5. MECHANISMS AND OPTIMIZATION OF COAL COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacos Zygourakis

    2000-10-31

    The completed research project has made some significant contributions that will help us meet the challenges outlined in the previous section. One of the major novelties of our experimental approach involves the application of video microscopy and digital image analysis to study important transient phenomena (like particle swelling and ignitions) occurring during coal pyrolysis and combustion. Image analysis was also used to analyze the macropore structure of chars, a dominant factor in determining char reactivity and ignition behavior at high temperatures where all the commercial processes operate. By combining advanced experimental techniques with mathematical modeling, we were able to achieve the main objectives of our project. More specifically: (1) We accurately quantified the effect of several important process conditions (like pyrolysis heating rate, particle size, heat treatment temperature and soak time) on the combustion behavior of chars. These measurements shed new light into the fundamental mechanisms of important transient processes like particle swelling and ignitions. (2) We developed and tested theoretical models that can predict the ignition behavior of char particles and their burn-off times at high temperatures where intraparticle diffusional limitations are very important.

  6. EXPERIMENTAL STUDY ON HORIZONTAL COMBUSTION TECHNIQUE FOR BITUMINOUS COAL BRIQUET

    Institute of Scientific and Technical Information of China (English)

    路春美; 程世庆; 邵延玲; 张晔

    1997-01-01

    Through a lot of experiments, a new kind of stove using horizontal combustion technique for bituminous coal briquet has been developed. Making use of this stove, studies have been made on burning process of bituminous coal briquet, distribution of temperature field in the stove, the regularities of evolution and combustion of volatile matter, the burning rate and efficiency of bituminous coal briquet, characteristics of fire-sealing and sulfur-retention. The results show that, with the technique, some achievements can be obtained in combustion of bituminous coal briquet, such as lower pollution that the flue gas black degree is below 0.5R and dust concentration is below 90mg/m3 . The stove's combustion efficiency reaches 90%, sulfur fixing efficiency is 60%, and CO concentration is decreased by 40% compared with other traditional stoves. With so many advantages, the stove can be used extensively in civil stoves and smaller industrial boilers.

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

    Science.gov (United States)

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

    2010-09-01

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

  8. 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.

  9. EVALUATION OF BROWN COAL SPONTANEOUS COMBUSTION AND SOURCES GENESIS PROGNOSES

    Directory of Open Access Journals (Sweden)

    Vlastimil MONI

    2014-10-01

    Full Text Available This article presents summarizing information about the solution of partial part of research problem of prognoses of deposited brown coal spontaneous combustion sources genesis as a part of project TA01020351 – program ALFA. We will gradually describe the results of long term measurements carried out on selected brown coal heaps realized from 2011 to 2013. The attention is devoted to characterization of key parameters. These parameters influence the genesis of combustion. The second problem is the comparison of results of thermal imaging with laboratory results of gas and coal samples sampled in situ, with the influence of atmospheric conditions (insolation, aeration, rainfall, atmospheric pressure changes etc., with influence of coal mass degradation, physical and chemical factors and another failure factors to brown coal spontaneous combustion processes.

  10. Coal power and combustion. Quarterly report, January--March 1977

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-12-01

    ERDA's coal combustion and power program has focused on two major areas: Direct combustion of coal and advanced power systems. Efforts in the area of direct combustion are concentrated on: Development of atmospheric and pressurized systems capable of burning high-sulfur coal of all rank and quality in fluidized-bed combustors; development of advanced technology power systems to generate power more economically than present technology permits while using medium- and high-sulfur coal in an environmentally-acceptable manner; development of the technology enabling coal-oil slurries to be substituted as feedstock for gas or oil-fired combustors; and improvement of the efficiency of present boilers. Compared with conventional coal-fired systems, fluidized-bed combustion systems give higher power generation efficiencies and cleaner exhaust gases, even when burning high-sulfur coals. If the fluidized-bed system is pressurized, additional economies in capital and operating costs may be realized. The benefits from high-pressure combustion are a reduction of furnace size due to decreased gas volume and better sulfur removal. High-pressure combustion, however, requires the development of equipment to clean the hot combustion products to make them suitable for use in power generation turbines. The advanced power systems program is directed toward developing electric power systems capable of operating on coal or coal-derived fuels. These systems involve the use of high temperature gas turbines burning low-Btu gas and turbine systems using inert gases and alkali metal vapors. Some 25 projects in these areas are described, including a brief summary of progress during the quarter. (LTN)

  11. Analysis of combustion efficiency in CFB coal combustors

    Energy Technology Data Exchange (ETDEWEB)

    Afsin Gungor [Nigde University, Nigde (Turkey). Department of Mechanical Engineering, Faculty of Engineering and Architecture

    2008-06-15

    Fluidized bed technology is well known for its high combustion efficiency and is widely used in coal combustion. In this study, the combustor efficiency has been defined and investigated for CFB coal combustor based on the losses using a dynamic 2D model. The model is shown to agree well with the published data. The effect of operating parameters such as excess air ratio, bed operational velocity, coal particle diameter and combustor load and the effect of design variables such as bed height and bed diameter on the mean bed temperature, the overall CO emission and the combustion efficiency are analyzed for the small-scale of CFBC in the presently developed model. As a result of this analysis, it is observed that the combustion efficiency decreases with increasing excess air value. The combustion efficiency increases with the bed operational velocity. Increasing coal particle size results in higher combustion efficiency values. The coal feed rate has negative effect on the combustion efficiency. The combustor efficiency considerably increases with increasing combustor height and diameter if other parameters are kept unchanged. 46 refs., 16 figs., 6 tabs.

  12. 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

  13. Reserch process geomigration during underground gasification and coal combustion

    Directory of Open Access Journals (Sweden)

    Zholudyev S.V.

    2014-12-01

    Full Text Available The chemical composition of subsoil water in the over- and subcoal deposits during underground combustion of brown coal can vary under coals thermal development product and pollution. Analysis of the substances-contaminants migratory in water is one of the main issues of further implementation of technologies UCG and UCC.

  14. The Production and Release of CFCs from Coal Combustion

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The destruction of the ozone layer in the atmosphere caused by industrially synthesized CFCs has aroused greatest concerns from the international society, but the CFCs formed from burning of coal containing fluorine have not been recognized by the world yet. In the present study, we condensed the gas through cold traps and used the GC-MS to measure the gas composition, and found that the content of CFC-12 in the smog from coal combustion was significantly higher than the background value of the local atmosphere. This proves that CFC-12 is formed in the process of coal combustion. This paper discusses a new source of non-synthesized CFCs.

  15. 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

  16. Compilation of Sandia coal char combustion data and kinetic analyses

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.E.; Hurt, R.H.; Baxter, L.L.; Hardesty, D.R.

    1992-06-01

    An experimental project was undertaken to characterize the physical and chemical processes that govern the combustion of pulverized coal chars. The experimental endeavor establishes a database on the reactivities of coal chars as a function of coal type, particle size, particle temperature, gas temperature, and gas and composition. The project also provides a better understanding of the mechanism of char oxidation, and yields quantitative information on the release rates of nitrogen- and sulfur-containing species during char combustion. An accurate predictive engineering model of the overall char combustion process under technologically relevant conditions in a primary product of this experimental effort. This document summarizes the experimental effort, the approach used to analyze the data, and individual compilations of data and kinetic analyses for each of the parent coals investigates.

  17. Chemical looping combustion of coal in interconnected fluidized beds

    Institute of Scientific and Technical Information of China (English)

    SHEN LaiHong; ZHENG Min; XIAO Jun; ZHANG Hui; XIAO Rui

    2007-01-01

    Chemical looping combustion is the indirect combustion by use of oxygen carrier.It can be used for CO2 capture in power generating processes. In this paper,chemical looping combustion of coal in interconnected fluidized beds with inherent separation of CO2 is proposed. It consists of a high velocity fluidized bed as an air reactor in which oxygen carrier is oxidized, a cyclone, and a bubbling fluidized bed as a fuel reactor in which oxygen carrier is reduced by direct and indirect reactions with coal. The air reactor is connected to the fuel reactor through the cyclone. To raise the high carbon conversion efficiency and separate oxygen carrier particle from ash, coal slurry instead of coal particle is introduced into the bottom of the bubbling fluidized bed. Coal gasification and the reduction of oxygen carrier with the water gas take place simultaneously in the fuel reactor. The flue gas from the fuel reactor is CO2 and water. Almost pure CO2 could be obtained after the condensation of water. The reduced oxygen carrier is then returned back to the air reactor, where it is oxidized with air. Thermodyanmics analysis indicates that NiO/Ni oxygen carrier is the optimal one for chemical looping combustion of coal.Simulation of the processes for chemical looping combustion of coal, including coal gasification and reduction of oxygen carrier, is carried out with Aspen Plus software. The effects of air reactor temperature, fuel reactor temperature, and ratio of water to coal on the composition of fuel gas, recirculation of oxygen carrier particles, etc., are discussed. Some useful results are achieved. The suitable temperature of air reactor should be between 1050-1150Cand the optimal temperature of the fuel reactor be between 900-950℃.

  18. Chemical looping combustion of coal in interconnected fluidized beds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chemical looping combustion is the indirect combustion by use of oxygen carrier. It can be used for CO2 capture in power generating processes. In this paper, chemical looping combustion of coal in interconnected fluidized beds with inherent separation of CO2 is proposed. It consists of a high velocity fluidized bed as an air reactor in which oxygen carrier is oxidized, a cyclone, and a bubbling fluidized bed as a fuel reactor in which oxygen carrier is reduced by direct and indirect reactions with coal. The air reactor is connected to the fuel reactor through the cyclone. To raise the high carbon conversion efficiency and separate oxygen carrier particle from ash, coal slurry instead of coal particle is introduced into the bottom of the bubbling fluidized bed. Coal gasification and the reduction of oxygen carrier with the water gas take place simultaneously in the fuel reactor. The flue gas from the fuel reactor is CO2 and water. Almost pure CO2 could be obtained after the con- densation of water. The reduced oxygen carrier is then returned back to the air reactor, where it is oxidized with air. Thermodyanmics analysis indicates that NiO/Ni oxygen carrier is the optimal one for chemical looping combustion of coal. Simulation of the processes for chemical looping combustion of coal, including coal gasification and reduction of oxygen carrier, is carried out with Aspen Plus software. The effects of air reactor temperature, fuel reactor temperature, and ratio of water to coal on the composition of fuel gas, recirculation of oxygen carrier par- ticles, etc., are discussed. Some useful results are achieved. The suitable tem- perature of air reactor should be between 1050―1150℃and the optimal temperature of the fuel reactor be between 900―950℃.

  19. Experimental study on pollution emission from combustion of blended coals

    Energy Technology Data Exchange (ETDEWEB)

    Li Yonghua; Chen Hongwei; Zhen Zhi; Liu Jizhen; Feng Zhaoxing; Dong Jianxun [North China Electric Power University, Baoding (China)

    2003-07-01

    The pollution brought by NOx and SOx produced by coal combustion is getting recognition by each country in the world. This paper adopts an experimental method, selects four kinds of lignite and three kinds of soft coal that are mainly used by some power plant and reports a study of the pollution emission characteristics of component and blended coals. The test rig is introduced from Canada with a capacity of 640 MJ/h with a complete milling system and flue gas online analysis system. The study focuses on the influence of oxygen concentration, pulverized coal fineness and pulverized coal nitrogen content on the pollution emission. The study is useful for achieving clean combustion in large power plants. 5 refs., 4 figs., 7 tabs.

  20. Assessment of the radiological impacts of utilizing coal combustion fly ash as main constituent in the production of cement.

    Science.gov (United States)

    Turhan, Seref; Arıkan, Ismail H; Köse, Abdullah; Varinlioğlu, Ahmet

    2011-06-01

    The purpose of this study is to assess potential radiological impacts of utilizing pulverized fly ash (PFA) as a constituent in ordinary Portland cement. For this purpose, the activity concentrations of (226)Ra, (232)Th, and (40)K in samples of PFA and Portland cement containing 15%, 20%, and 25% by mass PFA were measured using gamma-ray spectrometry with HPGe detector. The mean activity concentrations of (226)Ra, (232)Th, and (40)K were found as 366.6, 113.7, and 460.2 Bq kg( - 1), 94.2, 25.9, and 215.3 Bq kg( - 1), 113.7, 34.3, and 238.3 Bq kg( - 1), and 124.2, 41.8, and 279.3 Bq kg( - 1) for the examined samples of PFA, Portland cement with 15%, 20%, and 25% by mass PFA, respectively. Radiological parameters such as radium equivalent activity, external exposure index (activity concentration index), internal dose index (alpha index), indoor absorbed gamma dose rate, and the corresponding the annually effective dose were assessed for Portland cement samples containing three percentages (15%, 20%, and 25%) by mass PFA. The results of assessment show that all Portland cement samples are within the safe limits recommended for building materials for dwellings.

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

    Science.gov (United States)

    Kolker, A.; Senior, C.L.; Quick, J.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. ?? 2006 Elsevier Ltd. All rights reserved.

  2. The release of iron during coal combustion. Milestone report

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility

    1995-06-01

    Iron plays an important role in the formation of both fly ash and deposits in many pulverized-coal-fired boilers. Several authors indicate that iron content is a significant indicator of the slagging propensity of a majority of US bituminous coals, in particular eastern bituminous coals. The pyritic iron content of these coals is shown to be a particularly relevant consideration. A series of investigations of iron release during combustion is reported for a suite of coals ranging in rank from lignite to low-volatile bituminous coal under combustion conditions ranging from oxidizing to inert. Experimental measurements are described in which, under selected conditions, major fractions of the iron in the coal are released within a 25 ms period immediately following coal devolatilization. Mechanistic interpretation of the data suggest that the iron is released as a consequence of oxygen attack on porous pyrrhotite particles. Experimental testing of the proposed mechanism reveals that the release is dependent on the presence of both pyrite in the raw coal and oxygen in the gas phase, that slow preoxidation (weathering) of the pyrite significantly inhibits the iron release, and that iron loss increases as oxygen penetration of the particle increases. Each observation is consistent with the postulated mechanism.

  3. Chemical analyses of coal, coal-associated rocks and coal combustion products collected for the National Coal Quality Inventory

    Science.gov (United States)

    Hatch, Joseph R.; Bullock, John H.; Finkelman, Robert B.

    2006-01-01

    In 1999, the USGS initiated the National Coal Quality Inventory (NaCQI) project to address a need for quality information on coals that will be mined during the next 20-30 years. At the time this project was initiated, the publicly available USGS coal quality data was based on samples primarily collected and analyzed between 1973 and 1985. The primary objective of NaCQI was to create a database containing comprehensive, accurate and accessible chemical information on the quality of mined and prepared United States coals and their combustion byproducts. This objective was to be accomplished through maintaining the existing publicly available coal quality database, expanding the database through the acquisition of new samples from priority areas, and analysis of the samples using updated coal analytical chemistry procedures. Priorities for sampling include those areas where future sources of compliance coal are federally owned. This project was a cooperative effort between the U.S. Geological Survey (USGS), State geological surveys, universities, coal burning utilities, and the coal mining industry. Funding support came from the Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE).

  4. 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...... linearly with their content in fuel ash. This linear tendency was affected when the fuels were mixed with additives. The volatility of trace elements during combustion was assessed by applying a relative enrichment (RE) factor, and TEM–EDS analysis was conducted to provide qualitative interpretations.......%. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

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

  6. Combustion characteristics of coal and refuse from passenger trains.

    Science.gov (United States)

    Fu-min, Ren; Feng, Yue; Ming, Gao; Min, Yu

    2010-07-01

    Refuse from passenger trains is becoming a significant issue with the development of the Chinese railway. Co-firing is regarded as a promising thermal technology, both environmentally and economically, in reducing the quantity of refuse. The co-firing property of passenger train refuse with coal, however, may differ due to the differences in the composition of the refuse. In the present study, combustion properties of refuse from passenger train samples and the mixture of refuse with coal were studied in a tube furnace. Thermo analysis methods, such as thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and derivative thermogravimetry (DTG) analyses were employed to evaluate combustion performance. We found that the mixture of passenger train refuse and coal at a ratio of 1:1 has a lower ignition and burnout temperature than the coal-only sample. Moreover, refuse from railway passenger trains has more reactive combustion properties than the coal-only sample, and the addition of railway passenger train refuse to coal can promote the reactivity of coal.

  7. Pyrolysis and combustion behaviour of coal-MBM blends.

    Science.gov (United States)

    Skodras, G; Grammelis, P; Basinas, P

    2007-01-01

    In the present work, thermogravimetric analysis was employed in order to investigate the behaviour of MBM and their blends with Greek brown coal, under pyrolysis and combustion conditions. MBM presented enhanced pyrolysis rates reflecting its high volatile and low ash contents compared to Greek brown coal. Increased conversion rates were observed when MBM was added in the brown coal sample. Significant interactions were detected between the two fuel blend components leading to significant deviations from the expected behaviour. The catalytic effect of mineral matter on the pyrolysis of MBM resulted in reaction rate decrease and DTG curve shift to lower temperatures for the demineralised MBM. Alterations in the combustion process due to the mineral matter were minimal when testing the blends. Interactions maintained during combustion and lower reactivity of MBM was achieved due to the reduced oxygen content.

  8. Pyrolysis and combustion behaviour of coal-MBM blends

    Energy Technology Data Exchange (ETDEWEB)

    Skodras, G.; Grammelis, P.; Basinas, P. [Center for Research & Technology Hellas, Ptolemais (Greece)

    2007-01-15

    In the present work, thermogravimetric analysis was employed in order to investigate the behaviour of MBM (meat and bone meal) and their blends with Greek brown coal, under pyrolysis and combustion conditions. MBM presented enhanced pyrolysis rates reflecting its high volatile and low ash contents compared to Greek brown coal. Increased conversion rates were observed when MBM was added in the brown coal sample. Significant interactions were detected between the two fuel blend components leading to significant deviations from the expected behaviour. The catalytic effect of mineral matter on the pyrolysis of MBM resulted in reaction rate decrease and DTG curve shift to lower temperatures for the demineralised MBM. Alterations in the combustion process due to the mineral matter were minimal when testing the blends. Interactions maintained during combustion and lower reactivity of MBM was achieved due to the reduced oxygen content.

  9. Commercial Demonstration of Oxy-Coal Combustion Clean Power Technology

    Energy Technology Data Exchange (ETDEWEB)

    K.J. McCauley; K.C. Alexander; D.K. McDonald; N. Perrin; J.-P. Tranier [Babcock & Wilcox Power Generation Group (United Kingdom)

    2009-07-01

    Oxy-Coal Combustion is an advanced clean coal-based power generation technology with carbon capture and storage that will be Near Zero Emissions (NZEP), will capture and safely store CO{sub 2} in a geologic formation, and generate clean power for sale. This sustainable technology will utilize natural resources and support energy security goals. The unique benefits of oxy-coal combustion allow for near zero emissions of coal combustion products. The emissions of particulate matter, sulfur dioxide, nitrogen oxides and mercury will not only be below regulated levels, but all will be within the uncertainty of current industry measurement methods, essentially zero. This advanced technology will demonstrate all these reduced levels and will lead to commercially available NZEP plants for power generation. Since 1991, with the support of the US-DOE, Babcock & Wilcox Power Generation Group, Inc. (B&W PGG) and Air Liquide (AL) have worked to bring an advanced technology to the market for Carbon Capture and Storage (CCS) for coal-fired electric power generation plants. Oxy-coal combustion is now ready for at-scale demonstration leading directly to full scale commercialization and availability in the power generation marketplace. This paper will discuss the follow up of the results of the 30 MWth large pilot test program completed in December, 2008. This oxy-coal combustion technology has been through small lab pilot testing, large pilot testing, and a rigorous bottom-up integration and optimization analysis. Our paper will describe incorporating the best technological thinking for the integration of a modern PC-fired boiler, environmental control equipment, air separation unit (ASU) and compression purification unit (CPU). 5 refs., 3 figs.

  10. 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.

  11. A new theory of chemical method to prevent spontaneous combustion of coal

    Institute of Scientific and Technical Information of China (English)

    LU Wei

    2009-01-01

    In order to prevent spontaneous combustion of coal from the source, based on the study on the mechanism of spontaneous combustion of coal, especially the process of coal to self-ignite and different activate structures have different activation for oxidization, the new theory and mechanism with chemical inhibition that can change the tendency of spontaneous combustion of coal and let the activate structures deactivate were brought forward. Therefore, coal was not self-ignited under a certain temperature when being chemically inhibited.

  12. Low-rank coal research: Volume 3, Combustion research: Final report. [Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M. D.; Hajicek, D. R.; Zobeck, B. J.; Kalmanovitch, D. P.; Potas, T. A.; Maas, D. J.; Malterer, T. J.; DeWall, R. A.; Miller, B. G.; Johnson, M. D.

    1987-04-01

    Volume III, Combustion Research, contains articles on fluidized bed combustion, advanced processes for low-rank coal slurry production, low-rank coal slurry combustion, heat engine utilization of low-rank coals, and Great Plains Gasification Plant. These articles have been entered individually into EDB and ERA. (LTN)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-04-01

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

  14. MECHANISMS AND OPTIMIZATION OF COAL COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacos Zygourakis

    1998-05-01

    We report the development of a novel experimental technique that combines video microscopy and thermogravimetric analysis to optimize the detection of coal and char particle ignitions. This technique is particularly effective for detecting ignitions occurring in coal or char samples containing multiple particles, where other commonly used techniques fail. The new approach also allows for visualization of ignition mechanism. Devolatilized char particles appear to ignite heterogeneously, while coal particles may ignite homogeneously, heterogeneously or through a combination of both mechanisms.

  15. 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.

  16. Detection of Coal Mine Spontaneous Combustion by Fuzzy Inference System

    Institute of Scientific and Technical Information of China (English)

    SUN Ji-ping; SONG Shu; MA Feng-ying; ZHANG Ya-li

    2006-01-01

    The spontaneous combustion is a smoldering process and characterized by a slow burning speed and a long duration. Therefore, it is a hazard to coal mines. Early detection of coal mine spontaneous combustion is quite difficult because of the complexity of different coal mines. And the traditional threshold discriminance is not suitable for spontaneous combustion detection due to the uncertainty of coalmine combustion. Restrictions of the single detection method will also affect the detection precision in the early time of spontaneous combustion. Although multiple detection methods can be adopted as a complementarity to improve the accuracy of detection, the synthesized method will increase the complicacy of criterion, making it difficult to estimate the combustion. To solve this problem, a fuzzy inference system based on CRI (Compositional Rule of Inference) and fuzzy reasoning method FITA (First Infer Then Aggregate) are presented. And the neural network is also developed to realize the fuzzy inference system. Finally, the effectiveness of the inference system is demonstrated by means of an experiment.

  17. State-of-the-art combustion controls CO{sub 2} emissions from coal : part 1

    Energy Technology Data Exchange (ETDEWEB)

    Farzan, H.; Vecci, S.; McDonald, D.; McCauley, K. [Babcock and Wilcox Canada Ltd., Toronto, ON (Canada); Pranda, P.; Varagani, R.; Gautier, F.; Tranier, J.P.; Perrin, N. [Air Liquide Canada Inc., Montreal, PQ (Canada)

    2007-10-15

    This article provided highlights of a pilot-scale oxy coal combustion experiment for new and retrofitted boiler applications. The oxy-coal combustion technology was assessed with supercritical (SC) and ultra-supercritical (USC) steam cycles. The study was performed on bituminous coal at a 1.5 MWth pilot plant. Engineering and economic evaluations were used to demonstrate that oxy-coal combustion is less expensive than other technologies. A design and cost estimation of an oxy-coal and PC boiler was conducted to evaluate a regulatory design basis for an air separation unit (ASU) and carbon dioxide (CO{sub 2}) compression design systems. Different plant configurations considered in the study included a flue gas composition exiting system with 95 mol per cent 02 oxidant after drying specified moisture content; a flue gas composition exiting system with 99 mol per cent 02 oxidant; and flue gas purified to meet enhanced oil recovery (EOR) specifications. The results of the air-fired SC and USC boilers compared with amine scrubbing and SC and USC oxy-combustion cases showed an efficiency decrease of 11 and 12 per cent for the SC and USC cases. Oxy-combustion was also the lowest in cost of all CO{sub 2} technologies considered in the project. Results showed that conversion of air blown SC and USC designs for oxy-coal combustion facilitated CO{sub 2} capture, and resulted in net plant efficiency penalties of 11 to 12 per cent. No air emissions were released in cases modelled to meet CO{sub 2} specifications. It was concluded that the 95 per cent mole oxygen treatment is more economical than the 99 per cent mole oxygen system. 3 tabs., 3 figs.

  18. Numerical simulation of the coal combustion process initiated by a plasma source

    Science.gov (United States)

    Askarova, A. S.; Messerle, V. E.; Ustimenko, A. B.; Bolegenova, S. A.; Maksimov, V. Yu.

    2014-12-01

    Numerical experiments on the torch combustion of the coal dust prepared by a plasma-thermochemical treatment for combustion have been done using the method of three-dimensional simulation. It is shown that the plasma preparation of coal for combustion enables one to optimize the process, improve the conditions for inflammation and combustion and minimize the emissions of harmful substances.

  19. NITRIC OXIDE FORMATION DURING PULVERIZED COAL COMBUSTION

    Science.gov (United States)

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

  20. Critical Value of CO of Forecasting Coal Spontaneous Combustion

    Institute of Scientific and Technical Information of China (English)

    HE Qi-ling; DAI Guang-long; WANG De-ming

    2003-01-01

    CO has been used widely in the production process of colliery as an index gas to predict spontaneous combustion of coal. But in some collieries there are CO gas in the upper corner of the face all the times, sometime CO gas even exceeds the regulated critical index. This phenomenon is much more obvious in the fully-mechanized longwall face and fully-mechanized longwall and top-coal caving face. Although many measures of fire-proof and fire-extinguishing have been adopted, the flowing amount of CO gas can be only decreasd, but can not be eliminated completely. Using the different kinds of coal, the experiment of coal oxidation was made at the low temperature. The experiment indicates that some kinds of coal can produce CO under the condition of normal temperature oxidation, sometime the CO consistency is very high, and the intension of CO can be decreased with oxidation time prolonging. Selecting rational critical value of CO is the kev to predicting spontaneous combustion of coal correctly and reliably. The problem of selecting retional critical value of CO was studied. Finally, the amount of CO gas released by different kinds of coal was obtained under normal temperature condition.

  1. Thermochemical and trace element behavior of coal gangue, agricultural biomass and their blends during co-combustion.

    Science.gov (United States)

    Zhou, Chuncai; Liu, Guijian; Cheng, Siwei; Fang, Ting; Lam, Paul Kwan Sing

    2014-08-01

    The thermal decomposition behavior of coal gangue, peanut shell, wheat straw and their blends during combustion were determined via thermogravimetric analysis. The coal gangue/agricultural biomass blends were prepared in four weight ratios and oxidized under dynamic conditions from room temperature to 1000 °C by various heating rates. Kinetic models were carried out to evaluate the thermal reactivity. The overall mass balance was performed to assess the partition behavior of coal gangue, peanut shell and their blends during combustion in a fixed bed reactor. The decomposition processes of agricultural biomass included evaporation, release of volatile matter and combustion as well as char oxidation. The thermal reactivity of coal gangue could be improved through the addition of agricultural biomass in suitable proportion and subsequent appropriate heating rate during combustion. In combination with the heating value and base/acid ratio limitations, a blending ratio of 30% agricultural biomass is conservatively selected as optimum blending.

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

    DEFF Research Database (Denmark)

    Wu, Hao; Glarborg, Peter; Frandsen, Flemming

    2011-01-01

    Co-combustion of a bituminous coal and a solid recovered fuel (SRF) was carried out in an entrained flow reactor, and the influence of additives such as NaCl, PVC, ammonium sulphate, and kaolinite on co-combustion was investigated. The co-combustion experiments were carried out with SRF shares of 7...... corrosion potential during co-combustion of coal and SRF, except for the experiments with NaCl or PVC addition....

  3. Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

    Science.gov (United States)

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

    2016-08-01

    A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention.

  4. Nitrogen Chemistry in Fluidized Bed Combustion of Coal

    DEFF Research Database (Denmark)

    Jensen, Anker Degn

    The present Ph.D thesis describes an experimental and theoretical investigation of the formation and destruction of nitrogen oxides (NOx and N2O) in fluidized bed combustion (FBC) of coal. A review of the current knowledge of nitrogen chemistry in FBC is presented. The review covers both laboratory...... for the emission of NOx from FBC has been developed as part of a JOULE project. The model is based on the two-phase theory of fluidization for the bed with a Kunii-Levenspiel type freeboard model and includes submodels for coal devolatilization, combustion of volatiles and char and a detailed model of NO formation...... 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...

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

    Science.gov (United States)

    Zasina, Damian; Zawadzki, Jaroslaw

    2015-04-01

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

  6. Plasma Torch for Plasma Ignition and Combustion of Coal

    Science.gov (United States)

    Ustimenko, Alexandr; Messerle, Vladimir

    2015-09-01

    Plasma-fuel systems (PFS) have been developed to improve coal combustion efficiency. PFS is a pulverized coal burner equipped with arc plasma torch producing high temperature air stream of 4000 - 6000 K. Plasma activation of coal at the PFS increases the coal reactivity and provides more effective ignition and ecologically friendly incineration of low-rank coal. The main and crucial element of PFS is plasma torch. Simplicity and reliability of the industrial arc plasma torches using cylindrical copper cathode and air as plasma forming gas predestined their application at heat and power engineering for plasma aided coal combustion. Life time of these plasma torches electrodes is critical and usually limited to 200 hours. Considered in this report direct current arc plasma torch has the cathode life significantly exceeded 1000 hours. To ensure the electrodes long life the process of hydrocarbon gas dissociation in the electric arc discharge is used. In accordance to this method atoms and ions of carbon from near-electrode plasma deposit on the active surface of the electrodes and form electrode carbon condensate which operates as ``actual'' electrode. Complex physicochemical investigation showed that deposit consists of nanocarbon material.

  7. Coal blend combustion: fusibility ranking from mineral matter composition

    Energy Technology Data Exchange (ETDEWEB)

    C. Goni; S. Helle; X. Garcia; A. Gordon; R. Parra; U. Kelm; R. Jimenez; G. Alfaro [Universidad de Concepcion, Concepcion (Chile). Departamento de Ingenieria Metalurgica, Instituto de Geologia Economica Aplicada (GEA)

    2003-10-01

    Although coal blends are increasingly utilized at power plants, ash slagging propensity is a non-additive property of the pure coals and hence difficult to predict. Coal ash tendency to slag is related to its bulk chemistry and ash fusion temperatures, and the present study aims to compare the results obtained from thermodynamic simulation with characterization of samples obtained as outcomes of plant-based coal-blend combustion trials at three utilities located in the Centre and North of Chile. Pulverized coal and plant residues samples from five families of binary blends tested in an experimental program were characterized for chemistry, mineralogy and maceral composition. The slagging was evaluated by determination of fusion curves using the MTDATA software and NPLOX3 database for the main coal ash oxides. The ranking obtained was approximately the same as obtained from carbon in the fly ashes and from plant residues observations. The thermodynamic modeling was a valid option to predict the fusibility during the combustion of blends. 16 refs., 7 figs., 1 tab.

  8. 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.

  9. 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.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    . The straw and bark chars showed higher reactivity, about a factor of 4–5, than bituminous char at 850 °C. The difference in reactivity between biomass char and bituminous char decreased with increasing reaction temperature. The reaction rate expressions for NO reduction during simultaneous combustion......This paper reports an experimental study of NO reduction over chars of straw, bark, bituminous coal, and lignite. The experiments were performed in a fixed bed reactor in the temperature range 850–1150 °C. The chars were generated by in situ pyrolysis at the reaction temperature to minimize further...... thermal deactivation. The rates of NO reduction over char were studied by char combustion experiments and O2-free experiments respectively. Two simple models were applied to interpret the data from the char combustion experiments. One model assumed that combustion and NO release take place uniformly...

  11. Minimum secure speed of fully mechanized coal face based on critical temperature of coal spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    Wei LIU; Yue-Ping QIN; Yong-Jiang HAO; Tian-Zhu GUI; Jing-Yan JIA

    2013-01-01

    The critical temperature theory of spontaneous combustion of coal and the numerical simulation method are used to explore the minimum secure speed of fully mechanized coal face to prevent the spontaneous combustion in goaf.Combined with the actual situation of workface 31005 in a coal mine,the highest temperatures in goaf at different advancing speeds were obtained by the numerical simulation of spontaneous combustion in goaf,and then a power function equation between the highest temperature and the advancing speed was achieved by regression analysis.The advancing speed corresponding to the critical temperature value was taken as the minimum safe speed of workface based on the equation.Finally,the accuracy and reliability of the speed were verified by the actual advancing process of workface 31005.The results of this research show that the new judgment method of the minimum safety speed has a higher value to be applied in the field.

  12. Impact of nongray multiphase radiation in pulverized coal combustion

    Science.gov (United States)

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

    2016-11-01

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

  13. 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.

  14. 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

    Results from an experimental investigation of the mechanisms governing the ash aerosol size segregated composition resulting from the combustion of pulverized coal in a laboratory scale down-flow combustor are described. The results of modeling activities used to interpret the results of the experiments conducted under his subtask are also described in this section. Although results from the entire program are included, Phase II studies which emphasized: (1) alkali behavior, including a study of the interrelationship between potassium vaporization and sodium vaporization; and (2) iron behavior, including an examination of the extent of iron-aluminosilicate interactions, are highlighted. Idealized combustion determination of ash particle formation and surface stickiness are also described.

  15. Notes on Contributions to the Science of Rare Earth Element Enrichment in Coal and Coal Combustion Byproducts

    Directory of Open Access Journals (Sweden)

    James C. Hower

    2016-03-01

    Full Text Available Coal and coal combustion byproducts can have significant concentrations of lanthanides (rare earth elements. Rare earths are vital in the production of modern electronics and optics, among other uses. Enrichment in coals may have been a function of a number of processes, with contributions from volcanic ash falls being among the most significant mechanisms. In this paper, we discuss some of the important coal-based deposits in China and the US and critique classification systems used to evaluate the relative value of the rare earth concentrations and the distribution of the elements within the coals and coal combustion byproducts.

  16. 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.

  17. Modeling of Pulverized Coal Combustion in Cement Rotary Kiln

    OpenAIRE

    2006-01-01

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

  18. Experimental simulation and numerical analysis of coal spontaneous combustion process at low temperature

    Institute of Scientific and Technical Information of China (English)

    文虎; 徐精彩; 葛岭梅

    2001-01-01

    The characteristic of coal spontaneous, combustion includes oxidative property and exothermic capacity. It can really simulate the process of coal spontaneous combustion to use the large-scale experimental unit loading coal ! 000 kg. According to the field change of gas concentration and coal temperature determined through experiment of coal self-ignite at low temperature stage, and on the basis of hydromechanics and heat-transfer theory, some parameters can be calculated at different low temperature stage, such as, oxygen consumption rate, heat liberation intensity. It offers a theoretic criterion for quantitatively analyzing characteristic of coal self-ignite and forecasting coal spontaneous combustion. According to coal exothermic capability and its thermal storage surroundings, thermal equilibrium is applied to deduce the computational method of limit parameter of coal self-ignite. It offers a quantitative theoretic criterion for coal self-ignite forecasting and preventing. According to the measurement and test of spontaneous combustion of Haibei coal, some token parameter of Haibei coal,spontaneous combustion is quantitatively analyzed, such as, spontaneous combustion period of coal, critical temperature, oxygen consumption rate, heat liberation intensity, and limit parameter of coal self-ignite.

  19. Experimental simulation and numerical analysis of coal spontaneous combustion process at low temperature*

    Institute of Scientific and Technical Information of China (English)

    WEN Hu; XU Jing-cai; GE Ling-mei

    2001-01-01

    The characteristic of coal spontaneous combustion includes oxidative p roperty and exothermic capacity. It can really simulate the process of coal spon taneous combustion to use the large-scale experimental unit loading coal 1 000 kg. According to the field change of gas concentration and coal temperature determi ned through experiment of coal self-ignite at low temperature stage, and on the basis of hydromechanics and heat-transfer theory, some parameters can be calcul at ed at different low temperature stage, such as, oxygen consumption rate, heat li beration intensity. It offers a theoretic criterion for quantitatively analyzing characteristic of coal self-ignite and forecasting coal spontaneous combustion . According to coal exothermic capability and its thermal storage surroundings, t hermal equilibrium is applied to deduce the computational method of limit parame ter of coal self-ignite. It offers a quantitative theoretic criterion for coal s elf-ignite forecasting and preventing. According to the measurement and test of spontaneous combustion of Haibei coal, some token parameter of Haibei coal spont aneous combustion is quantitatively analyzed, such as, spontaneous combustion pe riod of coal, critical temperature, oxygen consumption rate, heat liberation int ensity, and limit parameter of coal self-ignite.

  20. Low-NO/SUB/x combustion of coal by vertical cyclone furnace (II): slag tap combustion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, M.; Kusakabe, T.; Matsumoto, T.; Miyajima, K.; Yamazaki, M.

    1983-01-01

    Slag tap combustion of coal was investigated in the hope of developing a method of low-NOx, low-dust combustion. Miike coal (heating value 7000 kcal/kg) was combusted with air preheated to approximately 650 C in the same experimental vertical cyclone furnace as that used in the previous study. The furnace temperature rose to 1510-1740 C and trouble-free slag tap combustion was achieved. The concentration of NO in the flue gas fell sharply with decreasing excess air ratio in the primary combustion chamber. 2 references.

  1. Environmental impact assessment of combustible wastes utilization in rotary cement kilns

    OpenAIRE

    2013-01-01

    This study focuses on the environmental impact assessment of the coal combustion and its substitution by alternative fuels from combustible wastes during Portland cement clinker sinterization in rotary cement kiln. Environmental impact assessment was carried out based on the fuels chemical composition and operating parameters of a rotary cement kiln in accordance with EURITS and IMPACT 2002+ methods.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-12-01

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

  3. Co-combustion of agricultural residues with coal in a fluidized bed combustor.

    Science.gov (United States)

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

    2009-02-01

    Power generation from biomass is an attractive technology that utilizes agricultural residual waste. In order to explain the behavior of biomass-fired fluidized bed incinerator, biomass sources from agricultural residues (rice husk and palm kernel) were co-fired with coal in a 0.15m diameter and 2.3m high fluidized bed combustor. The combustion efficiency and carbon monoxide emissions were studied and compared with those for pure coal combustion. Co-combustion of a mixture of biomass with coal in a fluidized bed combustor designed for coal combustion increased combustion efficiency up to 20% depending upon excess air levels. Observed carbon monoxide levels fluctuated between 200 and 900 ppm with the addition of coal. It is evident from this research that efficient co-firing of biomass with coal can be achieved with minimal modifications to existing coal-fired boilers.

  4. 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.

  5. Development of Regression Models for Assessing Fire Risk of Some Indian Coals

    OpenAIRE

    Devidas S. Nimaje; D.P. Tripathy; Santosh Kumar Nanda

    2013-01-01

    Spontaneous combustion of coals leading to mine fires is a major problem in Indian coal mines that creates serious safety and mining risk. A number of experimental techniques based on petrological, thermal and oxygen avidity studies have been used for assessing the spontaneous heating liability of coals all over the world. Crossing point temperature (CPT) is one of the most common methods in India to assess the fire risk of coal so that appropriate strategies and effective action plans could...

  6. Thermal behaviour and kinetics of coal/biomass blends during co-combustion.

    Science.gov (United States)

    Gil, M V; Casal, D; Pevida, C; Pis, J J; Rubiera, F

    2010-07-01

    The thermal characteristics and kinetics of coal, biomass (pine sawdust) and their blends were evaluated under combustion conditions using a non-isothermal thermogravimetric method (TGA). Biomass was blended with coal in the range of 5-80 wt.% to evaluate their co-combustion behaviour. No significant interactions were detected between the coal and biomass, since no deviations from their expected behaviour were observed in these experiments. Biomass combustion takes place in two steps: between 200 and 360 degrees C the volatiles are released and burned, and at 360-490 degrees C char combustion takes place. In contrast, coal is characterized by only one combustion stage at 315-615 degrees C. The coal/biomass blends presented three combustion steps, corresponding to the sum of the biomass and coal individual stages. Several solid-state mechanisms were tested by the Coats-Redfern method in order to find out the mechanisms responsible for the oxidation of the samples. The kinetic parameters were determined assuming single separate reactions for each stage of thermal conversion. The combustion process of coal consists of one reaction, whereas, in the case of the biomass and coal/biomass blends, this process consists of two or three independent reactions, respectively. The results showed that the chemical first order reaction is the most effective mechanism for the first step of biomass oxidation and for coal combustion. However, diffusion mechanisms were found to be responsible for the second step of biomass combustion.

  7. Study and application of plasticity plaster-slurry for preventing coal spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    LIU Ai-hua(刘爱华); CAI Kang-xu(蔡康旭); GUO Da(郭达); ZHANG Fu-sheng(张复胜)

    2003-01-01

    Introduced the modulation scheme, function and mechanism of plasticity plaster-slurry preventing coal spontaneous combustion. The applications show that the plasticity plaster-slurry has good hygroscopicity and adsorptivity. To spray it on the coal wall of tunnel can shut off leakage wind fast and effectively. To press it into the coal body can absorb the heat and descend the temperature, surround the coal pieces, eliminate the possibility of the fiery district resuming combustion.

  8. Small scale experiment on the plasma assisted thermal chemical preparation and combustion of pulverized coal

    Energy Technology Data Exchange (ETDEWEB)

    Masaya, Sugimoto; Koichi, Takeda [Akita Prefectural University (Japan); Solonenko, O.P. [Institute of Theoretical and Applied Mechanics, Novosibirsk (Russian Federation); Sakashita, M.; Nakamura, M. [Japan Technical Information Service, Tokyo (Japan)

    2001-07-01

    Ignition and stable combustion of pulverized coal with Nitrogen and Air plasmas are investigated experimentally for some different types of coal. The experimental results show that air plasma has strong effect for ignition and stabilization of coal combustion. In addition, suppression of NO{sub x} production could be possible even in air plasma. It is possible to ignite and burn stably for the inferior coal that contains volatile matter in the ratio of only 10% of dry total mass. (authors)

  9. 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).

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

    Science.gov (United States)

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

    2016-06-05

    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.

  11. Effects of electrical resistance on the spontaneous combustion tendency of coal and the interaction matrix concept

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    There have been several developments in determining the spontaneous combustion liability of coal. Most of the methods of concern have purely been based on the internal properties of the coal itself. The relation between the crossing-point method and the electrical resistance of coal was examined here to outline the spontaneous combustion tendency of coal. The electrical resistance property of coal was looked into as a decision-making parameter of the interaction matrix concept for the final decision on the spontaneous combustion tendency.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-05-15

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

  13. 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.

  14. Thermally induced structural changes in coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gavalas, G.R.; Flagan, R.C.

    1990-01-17

    The effect of particle shape on char burnout is investigated in the limit of shrinking core combustion. As a first step, the particle temperature is assumed to proceed in the shrinking core regime and under conditions of negligible Stefan flow. The problem then reduces to calculating the oxygen concentration field around a non-spherical particle with the oxidation reaction taking place on the external surface. This problem has been addressed by an analytical technique and a numerical technique. An analytical technique known as domain perturbation'' was used to examine the change due to reaction in the shape of a slightly nonspherical, but axisymmetric, particle. It was found that the aspect ratio always increases with conversion, i.e., the particle becomes less spherical. A numerical technique, based on the boundary integral'' method was developed to handle the case of an axisymmetric particle with otherwise arbitrary shape. Numerical results are presented which again show the aspect ratio to increase with conversion. 8 refs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-30

    ) Assessment of oxy-combustion impacts in two full-scale coal-fired utility boiler retrofits based on computational fluid dynamics (CFD) modeling of air-fired and oxygen-fired operation. This research determined that it is technically feasible to retrofit the combustion system in an air-fired boiler for oxy-fired operation. The impacts of CO{sub 2} flue gas recycle and burner 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) were minimal, with the exception of high sulfur levels resulting from untreated flue gas recycle with medium and high-sulfur coals. This work focused on combustion in the radiant and convective sections of the boiler and did not address boiler system integration issues, plant efficiencies, impacts on downstream air pollution control devices, or CO{sub 2} capture and compression. The experimental data, oxy-firing system principles and oxy-combustion process mechanisms provided by this work can be used by electric utilities, boiler OEMs, equipment suppliers, design firms, software vendors, consultants and government agencies to assess retrofit applications of oxy-combustion technologies to existing boilers and to guide development of new designs.

  16. Analysis of irrationality of coal susceptibility to spontaneous combustion determination method with fluid oxygen adsorption

    Institute of Scientific and Technical Information of China (English)

    HE Qi-lin

    2008-01-01

    Based on experiment results and theoretical analysis,pointed out that the method of coal susceptibility to spontaneous combustion determination with fluid oxygen adsorption can not present the essence of coal oxidation process and oxidation reaction.The method is incorrect,paying attention at one aspect and ignoring the rest.The method is not reasonable for coal susceptibility to spontaneous combustion determination.Susceptibility to spontaneous combustion of coal reflects chemical property of coal oxidation with oxygen absorption and heat release at low temperature.Coal's susceptibility to spontaneous combustion is mainly decided by the number of molecules with reaction activation energy and activation molecule production rate at certain temperature.Therefore,index of susceptibility to spontaneous combustion should adopt accumulative value or trend of heat release or oxygen adsorption during oxidation process.

  17. Analysis of irrationality of coal susceptibility to spontaneous combustion determination method with fluid oxygen adsorption

    Institute of Scientific and Technical Information of China (English)

    HE Qi-lin

    2008-01-01

    Based on experiment results and theoretical analysis, pointed out that the method of coal susceptibility to spontaneous combustion determination with fluid oxygen adsorption can not present the essence of coal oxidation process and oxidation reaction. The method is incorrect, paying attention at one aspect and ignoring the rest. The method is not reasonable for coal susceptibility to spontaneous combustion determination. Sus-ceptibility to spontaneous combustion of coal reflects chemical property of coal oxidation with oxygen absorption and heat release at low temperature. Coal's susceptibility to spon-taneous combustion is mainly decided by the number of molecules with reaction activation energy and activation molecule production rate at certain temperature. Therefore, index of susceptibility to spontaneous combustion should adopt accumulative value or trend of heat release or oxygen adsorption during oxidation process.

  18. Characterization of feed coal and coal combustion products from power plants in Indiana and Kentucky

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

    The US Geological Survey, Kentucky Geological Survey, and the University of Kentucky Center for Applied Energy Research are collaborating with Indiana and Kentucky utilities to determine the physical and chemical properties of feed coal and coal combustion products (CCP) from three coal-fired power plants. These three plants are designated as Units K1, K2, and I1 and burn high-, moderate-, and low-sulfur coals, respectively. Over 200 samples of feed coal and CCP were analyzed by various chemical and mineralogical methods to determine mode of occurrence and distribution of trace elements in the CCP. Generally, feed coals from all 3 Units contain mostly well-crystallized kaolinite and quartz. Comparatively, Unit K1 feed coals have higher amounts of carbonates, pyrite and sphalerite. Unit K2 feed coals contain higher kaolinite and illite/muscovite when compared to Unit K1 coals. Unit I1 feed coals contain beta-form quartz and alumino-phosphates with minor amounts of calcite, micas, anatase, and zircon when compared to K1 and K2 feed coals. Mineralogy of feed coals indicate that the coal sources for Units K1 and K2 are highly variable, with Unit K1 displaying the greatest mineralogic variability; Unit I1 feed coal however, displayed little mineralogic variation supporting a single source. Similarly, element contents of Units K1 and K2 feed coals show more variability than those of Unit I1. Fly ash samples from Units K1 and K2 consist mostly of glass, mullite, quartz, and spines group minerals. Minor amounts of illite/muscovite, sulfates, hematite, and corundum are also present. Spinel group minerals identified include magnetite, franklinite, magnesioferrite, trevorite, jacobisite, and zincochromite. Scanning Electron Microscope analysis reveals that most of the spinel minerals are dendritic intergrowths within aluminum silicate glass. Unit I1 fly ash samples contain glass, quartz, perovskite, lime, gehlenite, and apatite with minor amounts of periclase, anhydrite

  19. On-Line Analysis and Kinetic Behavior of Arsenic Release during Coal Combustion and Pyrolysis.

    Science.gov (United States)

    Shen, Fenghua; Liu, Jing; Zhang, Zhen; Dai, Jinxin

    2015-11-17

    The kinetic behavior of arsenic (As) release during coal combustion and pyrolysis in a fluidized bed was investigated by applying an on-line analysis system of trace elements in flue gas. This system, based on inductively coupled plasma optical emission spectroscopy (ICP-OES), was developed to measure trace elements concentrations in flue gas quantitatively and continuously. Obvious variations of arsenic concentration in flue gas were observed during coal combustion and pyrolysis, indicating strong influences of atmosphere and temperature on arsenic release behavior. Kinetic laws governing the arsenic release during coal combustion and pyrolysis were determined based on the results of instantaneous arsenic concentration in flue gas. A second-order kinetic law was determined for arsenic release during coal combustion, and the arsenic release during coal pyrolysis followed a fourth-order kinetic law. The results showed that the arsenic release rate during coal pyrolysis was faster than that during coal combustion. Thermodynamic calculations were carried out to identify the forms of arsenic in vapor and solid phases during coal combustion and pyrolysis, respectively. Ca3(AsO4)2 and Ca(AsO2)2 are the possible species resulting from As-Ca interaction during coal combustion. Ca(AsO2)2 is the most probable species during coal pyrolysis.

  20. Clean coal combustion: development of clean combustion technologies for residual fuels

    Energy Technology Data Exchange (ETDEWEB)

    Montiel, M.F. [Electric Research Institute, Cuernavaca (Mexico)

    2003-07-01

    Most of the large quantities of heavy fuel oil (about 4% sulphur-content) produced in Mexican refineries are burned in power plants. More natural gas is being used, and it is estimated that by 2010, about one-third of Mexico's electricity will be produced from natural gas. As petroleum and gas reserves are depleted, power plants will consume more imported coal. To continue combustion of dirty fuels, advanced clean combustion technologies must be developed. Two feasibility projects were conducted over the period 1989-1995 on combustion of Mexican fuels in a bubbling fluidized combustor and in IGCC power plants. More recent feasibility studies for cogeneration plants in refineries are outlined. Solid fuels for IGCC and CFB are among the most important developments. Over the period 2004-2008, projects to study clean combustion of Mexican fuels will be conducted in the following areas: operational problems in IGCC plants, construction of an entrained flow gasifier for synthesis gas production and for feeding of heavy fuels and coal emulsions, and development of CFD (computational fluid dynamics) models.

  1. Natural attenuation of coal combustion waste in river sediments.

    Science.gov (United States)

    Markwiese, James T; Rogers, William J; Carriker, Neil E; Thal, David I; Vitale, Rock J; Gruzalski, Jacob G; Rodgers, Erin E; Babyak, Carol M; Ryti, Randall T

    2014-08-01

    The weathering of coal combustion products (CCPs) in a lotic environment was assessed following the Tennessee Valley Authority (Kingston, TN) fly ash release of 2008 into surrounding rivers. Sampled materials included stockpiled ash and sediment collected from 180 to 880 days following the release. Total recoverable concentrations of heavy metals and metalloids in sediment were measured, and percent ash was estimated visually or quantified by particle counts. Arsenic and selenium in sediment were positively correlated with percent ash. For samples collected 180 days after the release, total concentrations of trace elements downstream of the release were greater than reference levels but less than concentrations measured in stockpiled ash. Total concentrations of trace elements remained elevated in ash-laden sediment after almost 2.5 years. A sequential extraction procedure (SEP) was used to speciate selected fractions of arsenic, copper, lead, nickel, and selenium in decreasing order of bioavailability. Concentrations of trace elements in sequentially extracted fractions were one to two orders of magnitude lower than total recoverable trace elements. The bulk of sequentially extractable trace elements was associated with iron-manganese oxides, the least bioavailable fraction of those measured. By 780 days, trace element concentrations in the SEP fractions approached reference concentrations in the more bioavailable water soluble, ion exchangeable, and carbonate-bound fractions. For each trace element, the percentage composition of the bioavailable fractions relative to the total concentration was calculated. These SEP indices were summed and shown to significantly decrease over time. These results document the natural attenuation of leachable trace elements in CCPs in river sediment as a result of the loss of bioavailable trace elements over time.

  2. Coal combustion science: Task 1, Coal char combustion: Task 2, Fate of mineral matter. Quarterly progress report, July--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.; Hurt, R.H.; Davis, K.A.; Baxter, L.L.

    1994-07-01

    Progress reports are presented for the following tasks: (1) kinetics and mechanisms of pulverized coal char combustion and (2) fate of inorganic material during coal combustion. The objective of Task 1 is to characterize the combustion behavior of selected US coals under conditions relevant to industrial pulverized coal-fired furnaces. In Sandia`s Coal Combustion Laboratory (CCL), optical techniques are used to obtain high-resolution images of individual burning coal char particles and to measure, in situ, their temperatures, sizes, and velocities. Detailed models of combustion transport processes are then used to determine kinetic parameters describing the combustion behavior as a function of coal type and combustion environment. Partially reacted char particles are also sampled and characterized with advanced materials diagnostics to understand the critical physical and chemical transformations that influence reaction rates and burnout times. The ultimate goal of the task is the establishment of a data base of the high temperature reactivities of chars from strategic US coals, from which important trends may be identified and predictive capabilities developed. The overall objectives for task 2 are: (1) to complete experimental and theoretical investigation of ash release mechanisms; (2) to complete experimental work on char fragmentation; (3) to establish the extent of coal (as opposed to char) fragmentation as a function of coal type and particle size; (4) to develop diagnostic capabilities for in situ, real-time, qualitative indications of surface species composition during ash deposition, with work continuing into FY94; (5) to develop diagnostic capabilities for in situ, real-time qualitative detection of inorganic vapor concentrations; and (6) to conduct a literature survey on the current state of understanding of ash deposition, with work continuing into FY94.

  3. Metallic species derived from fluidized bed coal combustion. [59 references

    Energy Technology Data Exchange (ETDEWEB)

    Natusch, D.F.S.; Taylor, D.R.

    1980-01-01

    Samples of fly ash generated by the combustion of Montana Rosebud coal in an experimental 18 inch fluidized bed combustor were collected. The use of a heated cascade impactor permitted collection of size fractionated material that avoided condensation of volatile gases on the particles. Elemental concentration trends were determined as a function of size and temperature and the results compared to published reports for conventional power plants. The behavior of trace metals appears to be substantially different in the two systems due to lower operating temperatures and the addition of limestone to the fluidized bed. Corrosion of the impactor plates was observed at the highest temperature and lowest limestone feed rate sampled during the study. Data from the elemental concentration and leaching studies suggest that corrosion is most likely due to reactions involving sodium sulfate. However, it is concluded that corrosion is less of a potential problem in fluidized-bed systems than in conventional coal-fired systems.

  4. A new SOx simulation model of coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Li Yonghua; Chen Hongwei; Zhen Zhi; Feng Zhaoxing; Dong Jianxun [North China Electric Power University, Baoding (China)

    2003-07-01

    It is very important to study the emission of pollutants from a coal combustion device, and we consider the best way is to use numerical simulation for such a study. By using a mathematical model with a post-processing method and based on combustion simulation, this paper reports the calculation of the SOx distribution in a power plant boiler furnace. For the formation of SOx, a conventional chemical reaction model is adopted, and according to the principles of reaction dynamics, a model for the SOx formation is also put forward. It is the first time the calculation and on-site testing an 800MW-unit boiler have been combined in China. The test and calculation results show that the model is reasonable, and such a study will be valuable as a reference for boiler design and clean operation. 5 refs., 1 fig., 3 tabs.

  5. Healy Clean Coal Project: A DOE Assessment

    Energy Technology Data Exchange (ETDEWEB)

    National Energy Technology Laboratory

    2003-09-01

    The goal of the U.S. Department of Energy's (DOE) Clean Coal Technology (CCT) Program is to provide the energy marketplace with advanced, more efficient, and environmentally responsible coal utilization options by conducting demonstrations of new technologies. These demonstration projects are intended to establish the commercial feasibility of promising advanced coal technologies that have been developed to a level at which they are ready for demonstration testing under commercial conditions. This document serves as a DOE post-project assessment (PPA) of the Healy Clean Coal Project (HCCP), selected under Round III of the CCT Program, and described in a Report to Congress (U.S. Department of Energy, 1991). The desire to demonstrate an innovative power plant that integrates an advanced slagging combustor, a heat recovery system, and both high- and low-temperature emissions control processes prompted the Alaska Industrial Development and Export Authority (AIDEA) to submit a proposal for this project. In April 1991, AIDEA entered into a cooperative agreement with DOE to conduct this project. Other team members included Golden Valley Electric Association (GVEA), host and operator; Usibelli Coal Mine, Inc., coal supplier; TRW, Inc., Space & Technology Division, combustor technology provider; Stone & Webster Engineering Corp. (S&W), engineer; Babcock & Wilcox Company (which acquired the assets of Joy Environmental Technologies, Inc.), supplier of the spray dryer absorber technology; and Steigers Corporation, provider of environmental and permitting support. Foster Wheeler Energy Corporation supplied the boiler. GVEA provided oversight of the design and provided operators during demonstration testing. The project was sited adjacent to GVEA's Healy Unit No. 1 in Healy, Alaska. The objective of this CCT project was to demonstrate the ability of the TRW Clean Coal Combustion System to operate on a blend of run-of-mine (ROM) coal and waste coal, while meeting strict

  6. Transformations of inorganic coal constituents in combustion systems

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-04-01

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

  8. Reducing the cost of Post Combustion Capture technology for Pulverized Coal Power Plants by flexible operation

    NARCIS (Netherlands)

    De Kler, R.C.F.; Verbaan, M.; Goetheer, E.L.V.

    2013-01-01

    Currently the low carbon prices, low Spreads and regulatory uncertainties hampers the business cases for coal-fired power plants with post-combustion capture (PCC) in Europe. Improvement of the business case of coal-fired power plants with post combustion capture requires a different approach in ter

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

    Science.gov (United States)

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

  10. 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.

  11. Pyrolysis of Compositions of Mixtures of Combustible Shales and Brown Coals Deposited in Belarus

    Science.gov (United States)

    Lishtvan, I. I.; Dudarchik, V. M.; Kraiko, V. M.; Belova, Yu. V.

    2013-11-01

    This paper presents the results of investigating the pyrolysis of compositions of mixtures of brown coals and combustible shales in a close-packed and a moving layer and the yield dynamics of the pyrolysis gas and resin. A comparative analysis of the quality of pyrolysis products obtained from combustible shales and brown coal and from their mixtures has been performed.

  12. Dynamic mathematical model and numerical calculation method on spontaneous combustion of loose coal

    Institute of Scientific and Technical Information of China (English)

    WEN Hu(文虎)

    2003-01-01

    Through the experiment of coal spontaneous combustion and relationship particle size with oxidation character of loose coal, some calculation formula of characteristic parameters is got in the process of coal spontaneous combustion. According to these theories of porous medium hydrodynamics, mass transfer and heat transfer, mathematical models of air leak field, oxygen concentration field and temperature field are set up. Through experimental and theoretical analysis, 3-D dynamic mathematical model of coal spontaneous combustion is set up. The method of ascertaining boundary condition of model is analyzed, and finite difference method is adopted to solve 2-D mathematical model.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  14. Co-combustion of different sewage sludge and coal: a non-isothermal thermogravimetric kinetic analysis.

    Science.gov (United States)

    Otero, M; Calvo, L F; Gil, M V; García, A I; Morán, A

    2008-09-01

    The kinetics of the combustion of coal, two different sewage sludge and their blends (containing different dried weight percentages of sewage sludge) was studied by simultaneous thermogravimetric analysis. Once the weight percentage of sludge in the blend was 10%, the effects on the combustion of coal were hardly noticeable in terms of weight loss. The Arrhenius activation energy corresponding to the co-combustion of the blends was evaluated by non-isothermal kinetic analysis. This showed that, though differences between coal and sewage sludge, the combustion of their blends kept kinetically alike to that of the coal. This work illustrates how thermogravimetric analysis may be used as an easy rapid tool to asses, not only mass loss, but also kinetics of the co-combustion of sewage sludge and coal blends.

  15. Mercury emission, control and measurement from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  16. Modelling of coal combustion enhanced through plasma-fuel systems in full-scale boilers

    Energy Technology Data Exchange (ETDEWEB)

    A.S. Askarova; Z. Jankoski; E.I. Karpenko; E.I. Lavrischeva; F.C. Lockwood; V.E. Messerle; A.B. Ustimenko [al-Farabi Kazakh National University, Almaty (Kazakhstan). Department of Physics

    2005-07-01

    Plasma activation promotes more effective and environmental friendly low-rank coal combustion. This work presents numerical modelling results of plasma thermochemical preparation of pulverized coal for ignition and combustion in the furnace of a utility boiler. Two kinetic mathematical models were used in the investigation of the processes of air-fuel mixture plasma activation, ignition and combustion. A 1D kinetic code, PLASMA-COAL, calculates the concentrations of species, temperatures and velocities of treated coal-air mixtures in a burner incorporating a plasma source. It gives initial data for 3D-modeling of power boilers furnaces by the code FLOREAN. A comprehensive image of plasma activated coal combustion processes in a furnace of pulverised coal fired boiler was obtained. The advantages of the plasma technology are clearly demonstrated. 15 refs., 6 figs., 4 tabs.

  17. Co-combustion of waste from olive oil production with coal in a fluidised bed.

    Science.gov (United States)

    Cliffe, K R; Patumsawad, S

    2001-01-01

    Waste from olive oil production was co-fired with coal in a fluidised bed combustor to study the feasibility of using this waste as an energy source. The combustion efficiency and CO emission were investigated and compared to those of burning 100% of coal. Olive oil waste with up to 20% mass concentration can be co-fired with coal in a fluidised bed combustor designed for coal combustion with a maximum drop of efficiency of 5%. A 10% olive oil waste concentration gave a lower CO emission than 100% coal firing due to improved combustion in the freeboard region. A 20% olive oil waste mixture gave a higher CO emission than both 100% coal firing and 10% olive oil waste mixture, but the combustion efficiency was higher than the 10% olive oil waste mixture due to lower elutriation from the bed.

  18. Investigation on thermal and trace element characteristics during co-combustion biomass with coal gangue.

    Science.gov (United States)

    Zhou, Chuncai; Liu, Guijian; Fang, Ting; Lam, Paul Kwan Sing

    2015-01-01

    The thermochemical behaviors during co-combustion of coal gangue (CG), soybean stalk (SS), sawdust (SD) and their blends prepared at different ratios have been determined via thermogravimetric analysis. The simulate experiments in a fixed bed reactor were performed to investigate the partition behaviors of trace elements during co-combustion. The combustion profiles of biomass was more complicated than that of coal gangue. Ignition property and thermal reactivity of coal gangue could be enhanced by the addition of biomass. No interactions were observed between coal gangue and biomass during co-combustion. The volatilization ratios of trace elements decrease with the increasing proportions of biomass in the blends during co-combustion. Based on the results of heating value, activation energy, base/acid ratio and gaseous pollutant emissions, the blending ratio of 20-30% biomass content is regarded as optimum composition for blending and could be applied directly at current combustion application with few modifications.

  19. Evaluation of the propensity for coal spontaneous combustion based on catastrophe theory

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-tao; ZHANG Xi-chen; TIEN Jerry C; LI Ya-qing

    2011-01-01

    Generally,different prevention measures should be taken according to spontaneous combustion propensities.The current methods to evaluate the propensity of coal spontaneous combustion,such as chromatographic method of oxygen adsorption,oxidation kinetics method and activation energy method,are mostly affected by human factors.Their boundaries among different classes of propensities were all established by subjective judgments.A new evaluation method using catastrophe theory is introduced.This method can accurately depict the process of coal spontaneous combustion and the evaluation index,"catastrophe temperature",be obtained based on the model.In terms of catastrophe temperature,the spontaneous combustion propensity of different coals can be sequenced.Experimental data indicate that this method is appropriate to describe the spontaneous combustion process and to evaluate the propensity of coal spontaneous combustion.

  20. Fluorine emission from com-bustion of steam coal of North China Plate and Northwest China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    To study the amount of fluorine emission from the combustion of the steam coal (mainly Permo-Carbonif- erous coal) from the North China Plate and Northwest China, the fluorine contents of the coal, the fly ash and the cinder in high-temperature power stations as well as mid-low temperature power stations have been analyzed. This note provides a rough estimate of the total annual amount of fluorine emission as well as emission ratio from steam coal combustion in China. Our results show that by combustion of 1 t of Permo-Carboniferous coal (containing roughly 100 g fluorine), high-temperature power stations emit roughly 90 g fluorine into the atmosphere. The fluorine emission ratio of coal combustion in high-temperature power stations is about 96% and that in mid-low temperature power stations is about 78%. A total of 800 million tons of coal is burnt in China every year, and the coal comes mainly from Permo- Carboniferous deposite in the North China Plate and Northwest China coal mines. Taking the average fluorine content of the coal used at a low value of 100 mg/kg, the total annual fluorine emission from steam coal combustion into the atmosphere is estimated to be 66398 t.

  1. [Emission factors of polycyclic aromatic hydrocarbons (PAHs) in residential coal combustion and its influence factors].

    Science.gov (United States)

    Hai, Ting-Ting; Chen, Ying-Jun; Wang, Yan; Tian, Chong-Guo; Lin, Tian

    2013-07-01

    As the emission source of polycyclic aromatic hydrocarbons (PAHs), domestic coal combustion has attracted increasing attention in China. According to the coal maturity, combustion form and stove type associated with domestic coal combustion, a large-size, full-flow dilution tunnel and fractional sampling system was employed to collect the emissions from five coals with various maturities, which were burned in the form of raw-coal-chunk (RCC)/honeycomb-coal-briquettes (HCB) in different residential stoves, and then the emission factors of PAHs (EF(PAHs)) were achieved. The results indicate that the EF(PAHs) of bituminous coal ranged from 1.1 mg x kg(-1) to 3.9 mg x kg(-1) for RCC and 2.5 mg x kg(-1) to 21. 1 mg x kg(-1) for HCB, and the anthracite EF(PAH8) were 0.2 mg x kg(-1) for RCC and 0.6 mg x kg(-1) for HCB, respectively. Among all the influence factors of emission factors of PAHs from domestic coal combustion, the maturity of coal played a major role, the range of variance reaching 1 to 2 orders of magnitude in coals with different maturity. Followed by the form of combustion (RCC/HCB), the EF(PAHs) of HCB was 2-6 times higher than that of RCC for the same geological maturity of the coal. The type of stove had little influence on EF(PAHs).

  2. Structure-Based Predictive model for Coal Char Combustion.

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, R.; Colo, J [Brown Univ., Providence, RI (United States). Div. of Engineering; Essenhigh, R.; Hadad, C [Ohio State Univ., Columbus, OH (United States). Dept. of Chemistry; Stanley, E. [Boston Univ., MA (United States). Dept. of Physics

    1997-09-24

    During the third quarter of this project, progress was made on both major technical tasks. Progress was made in the chemistry department at OSU on the calculation of thermodynamic properties for a number of model organic compounds. Modelling work was carried out at Brown to adapt a thermodynamic model of carbonaceous mesophase formation, originally applied to pitch carbonization, to the prediction of coke texture in coal combustion. This latter work makes use of the FG-DVC model of coal pyrolysis developed by Advanced Fuel Research to specify the pool of aromatic clusters that participate in the order/disorder transition. This modelling approach shows promise for the mechanistic prediction of the rank dependence of char structure and will therefore be pursued further. Crystalline ordering phenomena were also observed in a model char prepared from phenol-formaldehyde carbonized at 900{degrees}C and 1300{degrees}C using high-resolution TEM fringe imaging. Dramatic changes occur in the structure between 900 and 1300{degrees}C, making this char a suitable candidate for upcoming in situ work on the hot stage TEM. Work also proceeded on molecular dynamics simulations at Boston University and on equipment modification and testing for the combustion experiments with widely varying flame types at Ohio State.

  3. The effect of fuel pyrolysis on the coal particle combustion: An analytical investigation

    OpenAIRE

    Baghsheikhi Mostafa; Rahbari Alireza; Ashrafizadeh Seyed Mehdi; Bidabadi Mehdi

    2016-01-01

    The aim of this work is to analytically investigate the symmetrical combustion of an isolated coal particle with the fuel pyrolysis effect. The modelling concept of coal particles is similar to that of the liquid droplet combustion but in the case of coal devolatilization, the particles do not shrink like droplet does due to evaporation of liquid fuel. The rate of devolatilization of volatiles can be calculated using the equation that is similar to Arrheniu...

  4. Coal combustion science quarterly progress report, October--December 1992. Task 1, Coal char combustion [and] Task 2, Fate of mineral matter

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.] [Sandia National Labs., Livermore, CA (United States); Hurt, R.H.; Baxter, L.L. [Sandia National Labs., Albuquerque, NM (United States)

    1993-06-01

    In the Coal Combustion Laboratory (CCL) this quarter, controlled laboratory experiments were carried out to better understand the late stages of coal combustion and its relation to unburned carbon levels in fly ash. Optical in situ measurements were made during char combustion at high carbon conversions and the optical data were related to particle morphologies revealed by optical microscopy on samples extracted under the same conditions. Results of this work are reported in detail below. In the data presented below, we compare the fraction of alkali metal loss to that of the alkaline earth metals as a function of coal rank to draw conclusions about the mechanism of release for the latter. Figure 2.1 illustrates the fractional release of the major alkali and alkaline earth metals (Na, K, Ca, Mg) as a function of coal rank for a series of coals and for several coal blends. All data are derived from combustion experiments in Sandia`s Multifuel Combustor (MFC) and represent the average of three to eight experiments under conditions where the mass loss on a dry, ash-free (daf) basis exceeds 95 %. There are no missing data in the figure. The several coals with no indicated result exhibited no mass loss of the alkali or alkaline earth metals in our experiments. There is a clear rank dependence indicated by the data in Fig. 2.1, reflecting the mode of occurrence of the material in the coal.

  5. Mercury speciation and emissions from coal combustion in Guiyang, Southwest China.

    Science.gov (United States)

    Tang, Shunlin; Feng, Xinbin; Qiu, Jianrong; Yin, Guoxun; Yang, Zaichan

    2007-10-01

    Although China has been regarded as one of the largest anthropogenic mercury emission source with coal combustion, so far the actual measurements of Hg species and Hg emissions from the combustion and the capture of Hg in Chinese emission control devices were very limited. Aiming at Hg mercury species measurements in Guiyang, the capital city of Guizhou province in Southwest China, we studied flue gases of medium-to-small-sized industrial steam coal-firing boiler (10-30 t/h) with no control devices, medium-to-small-sized industrial steam coal-firing boiler with WFGD and large-scale coal combustion with ESPs using Ontario Hytro method. We obtained mercury emission factors of the three representative coal combustion and estimated mercury emissions in Guiyang in 2003, as well as the whole province from 1986 to 2002. Coal combustion in Guiyang emitted 1898 kg mercury to the atmosphere, of which 36% Hg is released from power plants, 41% from industrial coal combustion, and 23% from domestic users, and 267 kg is Hg(p), 813 kg is Hg(2+) and 817 kg is Hg0. Mercury emission in Guizhou province increased sharply from 5.8 t in 1986 to 16.4 t in 2002. With the implementation of national economic strategy of China's Western Development, the annual mercury emission from coal combustion in the province is estimated to be about 32 t in 2015.

  6. 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.

  7. Experiment study of optimization on prediction index gases of coal spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    牛会永; 邓湘陵; 李石林; 蔡康旭; 朱豪; 李芳; 邓军

    2016-01-01

    The coal of Anyuan Mine has the characteristic of easy spontaneous combustion. Conventional method is difficult to predict it. Coal samples from this mine were tested in laboratory. The data obtained from laboratory determination were initialized for the value which was defined as “K”. The ratio of each index gas and value of “K”, and the ratio of combination index gases and value of “K”, were analyzed simultaneously. The research results show that for this coal mine, if there is carbon monoxide in the gas sample, the phenomenon of oxidation and temperature rising for coal exists in this mine; if there is C2H4 in the gas sample, the temperature of coal perhaps exceeds 130 °C. If the coal temperature is between 35 °C and 130 °C, prediction and forecast for coal spontaneous combustion depend on the value ofΦ(CO)/K mainly; if the temperature of coal is between 130 °C and 300 °C, prediction and forecast for coal spontaneous combustion depend on the value ofΦ(C2H6)/Φ(C2H2)andΦ(C2H6)/K. The research results provide experimental basis for the prediction of coal spontaneous combustion in Anyuan coal mine, and have better guidance on safe production of this coal mine.

  8. Evolution of Submicrometer Organic Aerosols during a Complete Residential Coal Combustion Process.

    Science.gov (United States)

    Zhou, Wei; Jiang, Jingkun; Duan, Lei; Hao, Jiming

    2016-07-19

    In the absence of particulate matter (PM) control devices, residential coal combustion contributes significantly to ambient PM pollution. Characterizing PM emissions from residential coal combustion with high time resolution is beneficial for developing control policies and evaluating the environmental impact of PM. This study reports the evolution of submicrometer organic aerosols (OA) during a complete residential coal combustion process, that is, from fire start to fire extinction. Three commonly used coal types (bituminous, anthracite, and semicoke coals) were evaluated in a typical residential stove in China. For all three types of coal, the OA emission exhibited distinct characteristics in the four stages, that is, ignition, fierce combustion, relatively stable combustion, and ember combustion. OA emissions during the ignition stage accounted for 58.2-85.4% of the total OA emission of a complete combustion process. The OA concentration decreased rapidly during the fierce combustion stage and remained low during the relatively stable combustion stage. During these two stages, a significant ion peak of m/z 73 from organic acids were observed. The degree of oxidation of the OA increased from the first stage to the last stage. Implications for ambient OA source-apportionment and residential PM emission characterization and control are discussed.

  9. STRUCTURE-BASED PREDICTIVE MODEL FOR COAL CHAR COMBUSTION

    Energy Technology Data Exchange (ETDEWEB)

    CHRISTOPHER M. HADAD; JOSEPH M. CALO; ROBERT H. ESSENHIGH; ROBERT H. HURT

    1998-06-04

    During the past quarter of this project, significant progress continued was made on both major technical tasks. Progress was made at OSU on advancing the application of computational chemistry to oxidative attack on model polyaromatic hydrocarbons (PAHs) and graphitic structures. This work is directed at the application of quantitative ab initio molecular orbital theory to address the decomposition products and mechanisms of coal char reactivity. Previously, it was shown that the �hybrid� B3LYP method can be used to provide quantitative information concerning the stability of the corresponding radicals that arise by hydrogen atom abstraction from monocyclic aromatic rings. In the most recent quarter, these approaches have been extended to larger carbocyclic ring systems, such as coronene, in order to compare the properties of a large carbonaceous PAH to that of the smaller, monocyclic aromatic systems. It was concluded that, at least for bond dissociation energy considerations, the properties of the large PAHs can be modeled reasonably well by smaller systems. In addition to the preceding work, investigations were initiated on the interaction of selected radicals in the �radical pool� with the different types of aromatic structures. In particular, the different pathways for addition vs. abstraction to benzene and furan by H and OH radicals were examined. Thus far, the addition channel appears to be significantly favored over abstraction on both kinetic and thermochemical grounds. Experimental work at Brown University in support of the development of predictive structural models of coal char combustion was focused on elucidating the role of coal mineral matter impurities on reactivity. An �inverse� approach was used where a carbon material was doped with coal mineral matter. The carbon material was derived from a high carbon content fly ash (Fly Ash 23 from the Salem Basin Power Plant. The ash was obtained from Pittsburgh #8 coal (PSOC 1451). Doped

  10. Reaction Kinetic Equation for Char Combustion of Underground Coal Gasification

    Institute of Scientific and Technical Information of China (English)

    YU Hong-guan; YANG Lan-he; FENG Wei-min; LIU Shu-qin; SONG Zhen-qi

    2006-01-01

    Based on the quasi-steady-state approximation, the dynamic equation of char combustion in the oxidation zone of underground coal gasification (UCG) was derived. The parameters of the dynamic equation were determined at 900℃ using a thermo-gravimetric (TG) analyzer connected to a flue gas analyzer and this equation. The equation was simplified for specific coals, including high ash content, low ash content, and low ash fusibility ones. The results show that 1) the apparent reaction rate constant increases with an increase in volatile matter value as dry ash-free basis, 2) the effective coefficient of diffusion decreases with an increase in ash as dry basis, and 3) the mass transfer coefficient is independent of coal quality on the whole. The apparent reaction rate constant, mass-transfer coefficient and effective coefficient of diffusion of six char samples range from 7.51×104 m/s to 8.98×104 m/s, 3.05×106 m/s to 3.23×106 m/s and 5.36×106 m2/s to 8.23×106 m2/s at 900℃, respectively.

  11. Energy recycling by co-combustion of coal and recovered paint solids from automobile paint operations.

    Science.gov (United States)

    Suriyawong, Achariya; Magee, Rogan; Peebles, Ken; Biswas, Pratim

    2009-05-01

    During the past decade, there has been substantial interest in recovering energy from many unwanted byproducts from industries and municipalities. Co-combustion of these products with coal seems to be the most cost-effective approach. The combustion process typically results in emissions of pollutants, especially fine particles and trace elements. This paper presents the results of an experimental study of particulate emission and the fate of 13 trace elements (arsenic [As], barium [Ba], cadmium [Cd], chromium [Cr], copper [Cu], cobalt [Co], manganese [Mn], molybdenum [Mo], nickel [Ni], lead [Pb], mercury [Hg], vanadium [V], and zinc [Zn]) during combustion tests of recovered paint solids (RPS) and coal. The emissions from combustions of coal or RPS alone were compared with those of co-combustion of RPS with subbituminous coal. The distribution/partitioning of these toxic elements between a coarse-mode ash (particle diameter [dp] > 0.5 microm), a submicrometer-mode ash (dp combustion of RPS alone were lower in concentration and smaller in size than that from combustion of coal. However, co-combustion of RPS and coal increased the formation of submicrometer-sized particles because of the higher reducing environment in the vicinity of burning particles and the higher volatile chlorine species. Hg was completely volatilized in all cases; however, the fraction in the oxidized state increased with co-combustion. Most trace elements, except Zn, were retained in ash during combustion of RPS alone. Mo was mostly retained in all samples. The behavior of elements, except Mn and Mo, varied depending on the fuel samples. As, Ba, Cr, Co, Cu, and Pb were vaporized to a greater extent from cocombustion of RPS and coal than from combustion of either fuel. Evidence of the enrichment of certain toxic elements in submicrometer particles has also been observed for As, Cd, Cr, Cu, and Ni during co-combustion.

  12. The effect of emission from coal combustion in nonindustrial sources on deposition of sulfur and oxidized nitrogen in Poland.

    Science.gov (United States)

    Kryza, Maciej; Werner, Małgorzata; Błaś, Marek; Dore, Anthony J; Sobik, Mieczysław

    2010-07-01

    Poland has one of the largest sulfur and nitrogen emissions in Europe. This is mainly because coal is a main fuel in industrial and nonindustrial combustion. The aim of this paper is to assess the amount of sulfur and nitrogen deposited from SNAP sector 02 (nonindustrial sources) coal combustion. To assess this issue, the Fine Resolution Atmospheric Multipollutant Exchange (FRAME) model was used. The results suggest that industrial combustion has the largest impact on deposition of oxidized sulfur, whereas the oxidized nitrogen national deposition budget is dominated by transboundary transport. The total mass of pollutants deposited in Poland, originating from nonindustrial coal combustion, is 45 Gg of sulfur and 2.5 Gg of nitrogen, which is over 18% of oxidized sulfur and nearly 2% of oxidized nitrogen deposited. SNAP 02 is responsible for up to 80% of dry-deposited sulfur and 11% of nitrogen. The contribution to wet deposition is largest in central Poland in the case of sulfur and in some areas can exceed 11%. For oxidized nitrogen, nonindustrial emissions contribute less than 1% over the whole area of Poland. The switch from coal to gas fuel in this sector will result in benefits in sulfur and nitrogen deposition reduction.

  13. Comparison of an Internal Combustion Engine Derating Operated on Producer Gas from Coal and Biomass Gasification

    Directory of Open Access Journals (Sweden)

    Muhammad Ade Andriansyah Efendi

    2016-06-01

    Full Text Available Gasification is an effective and clean way to convert coal and biomass into useful fuels and chemical feedstocks. Producer gas utilization for internal combustion engine has been studied, not only from biomass gasification but also from coal gasification. This paper compares the research that has done author using coal gasification with other research results using biomass gasification. Coal gasifier performance test conducted with capacity of 20 kg/h coal. The proximate and ultimate analysis of raw coal, ash product and producer gas was conducted and comparised. The result of analysis shows that the efficiency of the coal gasification was 61% while range of gasifier efficiency for biomass is between 50-80%. Meanwhile, the experimental results on the performance of internal combustion engines using gas producer shows that the derating for power generation using coal producer gas was 46% and biomass was 20-50% depend on compression ratio of engine and characteristic of producer gas. 

  14. Naturally Occurring Radioactive Materials in Coals and Coal Combustion Residuals in the United States.

    Science.gov (United States)

    Lauer, Nancy E; Hower, James C; Hsu-Kim, Heileen; Taggart, Ross K; Vengosh, Avner

    2015-09-15

    The distribution and enrichment of naturally occurring radioactive materials (NORM) in coal combustion residuals (CCRs) from different coal source basins have not been fully characterized in the United States. Here we provide a systematic analysis of the occurrence of NORM ((232)Th, (228)Ra, (238)U, (226)Ra, and (210)Pb) in coals and associated CCRs from the Illinois, Appalachian, and Powder River Basins. Illinois CCRs had the highest total Ra ((228)Ra + (226)Ra = 297 ± 46 Bq/kg) and the lowest (228)Ra/(226)Ra activity ratio (0.31 ± 0.09), followed by Appalachian CCRs (283 ± 34 Bq/kg; 0.67 ± 0.09), and Powder River CCRs (213 ± 21 Bq/kg; 0.79 ± 0.10). Total Ra and (228)Ra/(226)Ra variations in CCRs correspond to the U and Th concentrations and ash contents of their feed coals, and we show that these relationships can be used to predict total NORM concentrations in CCRs. We observed differential NORM volatility during combustion that results in (210)Pb enrichment and (210)Pb/(226)Ra ratios greater than 1 in most fly-ash samples. Overall, total NORM activities in CCRs are 7-10- and 3-5-fold higher than NORM activities in parent coals and average U.S. soil, respectively. This study lays the groundwork for future research related to the environmental and human health implications of CCR disposal and accidental release to the environment in the context of this elevated radioactivity.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-08-01

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

  16. Studying the specific features pertinent to combustion of chars obtained from coals having different degrees of metamorphism and biomass chars

    Science.gov (United States)

    Bestsennyi, I. V.; Shchudlo, T. S.; Dunaevskaya, N. I.; Topal, A. I.

    2013-12-01

    Better conditions for igniting low-reaction coal (anthracite) can be obtained, higher fuel burnout ratio can be achieved, and the problem of shortage of a certain grade of coal can be solved by firing coal mixtures and by combusting coal jointly with solid biomass in coal-fired boilers. Results from studying the synergetic effect that had been revealed previously during the combustion of coal mixtures in flames are presented. A similar effect was also obtained during joint combustion of coal and wood in a flame. The kinetics pertinent to combustion of char mixtures obtained from coals characterized by different degrees of metamorphism and the kinetics pertinent to combustion of wood chars were studied on the RSK-1D laboratory setup. It was found from the experiments that the combustion rate of char mixtures obtained from coals having close degrees of metamorphism is equal to the value determined as a weighted mean rate with respect to the content of carbon. The combustion rate of char mixtures obtained from coals having essentially different degrees of metamorphism is close to the combustion rate of more reactive coal initially in the process and to the combustion rate of less reactive coal at the end of the process. A dependence of the specific burnout rate of carbon contained in the char of two wood fractions on reciprocal temperature in the range 663—833 K is obtained. The combustion mode of an experimental sample is determined together with the reaction rate constant and activation energy.

  17. Control of combustion area using electrical resistivity method for underground coal gasification

    Institute of Scientific and Technical Information of China (English)

    Selivanova Tatiana; Grebenyuk Igor; Belov Alexey

    2012-01-01

    Underground coal gasification (UCG) is one of the clean technologies to collect heat energy and gases (hydrogen,methane,etc.) in an underground coal seam.It is necessary to further developing environmentally friendly UCG system construction.One of the most important UCG's problems is underground control of combustion area for efficient gas production,estimation of subsidence and gas leakage to the surface.For this objective,laboratory experiments were conducted according to the UCG model to identify the process of combustion cavity development by monitoring the electrical resistivity activity on the coal samples to setup fundamental data for the technology engineering to evaluate combustion area.While burning coal specimens,that had been sampled from various coal deposits,electrical resistivity was monitored.Symmetric four electrodes system (ABMN) of direct and low-frequency current electric resistance method was used.for laboratory resistivity measurement of rock samples.Made research and the results suggest that front-end of electro conductivity activity during heating and combusting of coal specimen depended on heating temperature.Combusting coal electro conductivity has complicated multistage type of change.Electrical resistivity method is expected to be a useful geophysical tool to for evaluation of combustion volume and its migration in the coal seam.

  18. Comparative analysis for performance of brown coal combustion in a vortex furnace with improved design

    Science.gov (United States)

    Krasinsky, D. V.

    2016-09-01

    Comparative study of 3D numerical simulation of fluid flow and coal-firing processes was applied for flame combustion of Kansk-Achinsk brown coal in a vortex furnace of improved design with bottom injection of secondary air. The analysis of engineering performance of this furnace was carried out for several operational modes as a function of coal grinding fineness and coal input rate. The preferable operational regime for furnace was found.

  19. 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.

  20. JV Task 108 - Circulating Fluidized-Bed Combustion and Combustion Testing of Turkish Tufanbeyli Coal

    Energy Technology Data Exchange (ETDEWEB)

    Douglas Hajicek; Jay Gunderson; Ann Henderson; Stephen Sollom; Joshua Stanislowski

    2007-08-15

    Two combustion tests were performed at the Energy & Environmental Research Center (EERC) using Tufanbeyli coal from Turkey. The tests were performed in a circulating fluidized-bed combustor (CFBC) and a pulverized coal-fired furnace, referred to as the combustion test facility (CTF). One of the goals of the project was to determine the type of furnace best suited to this coal. The coal is high in moisture, ash, and sulfur and has a low heating value. Both the moisture and the sulfur proved problematic for the CTF tests. The fuel had to be dried to less than 37% moisture before it could be pulverized and further dried to about 25% moisture to allow more uniform feeding into the combustor. During some tests, water was injected into the furnace to simulate the level of flue gas moisture had the fuel been fed without drying. A spray dryer was used downstream of the baghouse to remove sufficient sulfur to meet the EERC emission standards permitted by the North Dakota Department of Health. In addition to a test matrix varying excess air, burner swirl, and load, two longer-term tests were performed to evaluate the fouling potential of the coal at two different temperatures. At the lower temperature (1051 C), very little ash was deposited on the probes, but deposition did occur on the walls upstream of the probe bank, forcing an early end to the test after 2 hours and 40 minutes of testing. At the higher temperature (1116 C), ash deposition on the probes was significant, resulting in termination of the test after only 40 minutes. The same coal was burned in the CFBC, but because the CFBC uses a larger size of material, it was able to feed this coal at a higher moisture content (average of 40.1%) compared to the CTF (ranging from 24.2% to 26.9%). Sulfur control was achieved with the addition of limestone to the bed, although the high calcium-to-sulfur rate required to reduce SO{sub 2} emissions resulted in heat loss (through limestone calcination) and additional ash

  1. Combustion characterization of coals for industrial applications. Final technical report, January 1, 1981-May 29, 1985

    Energy Technology Data Exchange (ETDEWEB)

    Nsakala, N.; Patel, R.L.; Lao, T.C.

    1985-03-01

    In-depth fundamental information was obtained from a two-inch inner diameter laminar flow reactor referred to as the Drop Tube Furnace System (DTFS). This information consists of the following: (1) pyrolysis kinetic characteristics of four coals of various rank (Texas lignite, Montana subbituminous, Alabama high volatile bituminous, and Pennsylvania anthracite); and (2) combustion kinetic studies of chars produced from the foregoing parent coals. A number of standard ASTM and special in-house bench scale tests were also performed on the coals and chars prepared therefrom to characterize their physicochemical properties. The pilot scale (500,000 Btu/hr) Controlled Mixing History Furnace (CMHF) was used to determine the effect of staged combustion on NO/sub x/ emissions control from an overall combustion performance of the Alabama high volatile bituminous coal. The quantitative fundamental data developed from this study indicate significant differences in coal/char chemical, physical, and reactivity characteristics, which should be useful to those interested in modeling coal combustion and pyrolysis processes. These results underscore the fact that coal selection is one of the keys governing a successful coal conversion/utilization process. The combustion kinetic information obtained on the high volatile bituminous coal has been used in conjunction with combustion engineering's proprietary mathematical models to predict the combustion performance of this coal in the Controlled Mixing History Furnace. Comparison of the predicted data with the experimental results shows a virtually one-to-one scale-up from the DTFS to the CMHF. These data should provide vital information to designers in the area of carbon burnout and NO/sub x/ reduction for large scale coal utilization applications. 31 refs., 28 figs., 17 tabs.

  2. Innovative oxy-coal combustion process suitable for future and more efficient zero emission power plants

    Energy Technology Data Exchange (ETDEWEB)

    Benelli, G.; Malavasi, M.; Girardi, G. [ENEL Ricerca (Italy)

    2007-07-01

    The problem with CO{sub 2} capture from a flue gas stream is related to its low concentration, which makes the process of separation very energy-intensive, complex and, as a result, expensive. The CO{sub 2} separation process can be optimized by increasing the concentration of CO{sub 2} and reducing nitrogen concentration in the stream as it happens, in the oxy-fuel combustion process. In such a case, the oxidant flow is typically a mixture of oxygen, steam and carbon dioxide, with a very low concentration of nitrogen. Since the oxy-combustion process leads to very high temperatures, flue gases must be circulating through the chemical reactor to keep the combustion adiabatic temperature below acceptable values, due to the limits imposed by material resistance. This paper focuses on an innovative oxy-coal combustion process named ISOTHERM{reg_sign}, based on a flameless combustion technique which is mentioned in recent literature also as 'Mild' combustion. The combustion process takes place within a pressurized and refractory-lined furnace, approaching temperatures close to 2000 K. The process has been experienced at pressurized conditions up to 4 bar on a 5 MW pilot plant for thousands of hours. In this paper, starting from a detailed description of the process, results obtained by the preliminary experimental tests are presented and discussed. Then, a development and demonstration program to assess the suitability of this technology for zero emission power generation at large scale in one of the units of Brindisi power station is presented. 10 refs., 5 figs., 2 tabs.

  3. Investigation of formation of nitrogen compounds in coal combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Blair, D.W.; Crane, I.D.; Wendt, J.O.L.

    1983-10-01

    This is the final report on DOE contract number DE-AC21-80MC14061. It concerns the formation of nitrogen oxide from fuel-bound nitrogen during coal combustion. The work reported was divided into three tasks. They addressed problems of time-resolving pyrolysis rates of coal under simulated combustion conditions, the combustion of the tar that results from such pyrolysis, and theoretical modeling of the pyrolysis process. In all of these tasks, special attention was devoted to the fate of coal nitrogen. The first two tasks were performed by Exxon Research and Engineering Company. 49 references.

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

    Directory of Open Access Journals (Sweden)

    Raffaele Cioffi

    2013-10-01

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

  5. Thermally induced structural changes in coal combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Flagan, R.C.; Gavalas, G.R.

    1992-01-01

    The effects of the temperature-time history during coal devolitization and oxidation on the physical properties and the reactivity of resulting char were studied experimentally for temperatures and residence times typical of pulverized combustion. Experiments were also carried out at somewhat lower temperatures and correspondingly longer residence times. An electrically heated laminar flow reactor was used to generate char and measure the rates of oxidation at gas temperatures about 1600K. Partially oxidized chars were extracted and characterized by gas adsorption and mercury porosimetry, optical and scanning electron microscopy, and oxidation in a thermogravimetric analysis system (TGA). A different series of experiments was conducted using a quadrople electrodynamic balance. Single particles were suspended electrodynamically and heated by an infrared laser in an inert or oxygen-containing atmosphere. During the laser heating, measurements were taken of particle mass, size/shape, and temperature.

  6. Utilization of coal combustion fly ash in terracotta bodies

    Energy Technology Data Exchange (ETDEWEB)

    Kara, A.; Kurama, S. [Dept. of Materials Science and Engineering, Anadolu Univ., Eskisehir (Turkey); Kurama, H.; Kara, Y. [Osmangazi Univ., Mining Engineering Dept., Eskisehir (Turkey)

    2004-07-01

    In this present work, coal combustion fly ash from a power plant in Turkey was used in combination with a traditional raw material in terracotta production with the aim of having a product with improved physico-mechanical properties and lower production cost. Several compositions were prepared by adding different amounts of fly ash (ranging from 0 to 20%) in a yellow firing terracotta formulation and shaped by wet pressing. Following firing at a suitable temperature, some of the physical properties of the resultant tiles were determined as a function of the fly ash content. A combination of XRD, SEM and EDX techniques were also employed to correlate the properties with the phase composition. The results indicated that fly ash could be utilized easily in certain amounts in such an application. (orig.)

  7. Influence of Process Parameters on Coal Combustion Performance

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der

    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...... study has been performed in order to initiate an investigation of the potential of chemical engineering models to predict NO from pulverized fuel burners. The success of chemical engineering modeling is strongly connected to the simplification of the flow pattern into a reactor configuration...... and swirl number on the flow pattern in the near burner zone of the laboratory furnace-model were studied. Experimentally obtained residence time distributions have been used to derive a chemical reaction engineering model for the mixing process. The model is based on a combination of plug flow reactors...

  8. Chromium speciation in coal and biomass co-combustion products.

    Science.gov (United States)

    Stam, Arthur F; Meij, Ruud; Te Winkel, Henk; Eijk, Ronald J van; Huggins, Frank E; Brem, Gerrit

    2011-03-15

    Chromium speciation is vital for the toxicity of products resulting from co-combustion of coal and biomass. Therefore, understanding of formation processes has been studied using a combination of X-ray absorption fine structure (XAFS) spectroscopy and thermodynamic equilibrium calculations. The influence of cofiring on Cr speciation is very dependent on the type of fuel. Cr(VI) contents in the investigated fly ash samples from coal and cofiring average around 7% of the total chromium. An exception is cofiring 7-28% wood for which ashes exhibited Cr(VI) concentrations of 12-16% of the total chromium. Measurements are in line with thermodynamic predictions: RE factors of Cr around 1 are in line with volatile Cr only above 1400 °C; lower Cr(VI) concentrations with lower oxygen content and Cr(III) dissolved in aluminosilicate glass. Stability of Cr(VI) below 700 °C does not correlate with Cr(VI) concentrations found in the combustion products. It is indicated that Cr(VI) formation is a high-temperature process dependent on Cr evaporation (mode of occurrence in fuel, promoted by organic association), oxidation (local oxygen content), and formation of solid chromates (promoted by presence of free lime (CaO) in the ash). CaCrO(4)(s) is a probable chemical form but, given different leachable fractions (varying from 25 to 100%), different forms of Cr(VI) must be present. Clay-bound Cr is likely to dissolve in the aluminosilicate glass phase during melting of the clay.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-01

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

  10. RESEARCH OF LEVEL OF SPONTANEOUS COMBUSTION ON COAL HEAPS GENESIS DANGER

    Directory of Open Access Journals (Sweden)

    Vlastimil MONI

    2014-07-01

    Full Text Available The article presents the summary of information about the spontaneous combustion of brown coal mass on coal heaps. It describes the procedure “The evaluation of the degree of the danger for the genesis of the spontaneous combustion of coal on coal heaps”. The evaluation includes analysis of important influencing factors. The conclusion of this article contains definite text of the proposition. It will be verified in the last year of the solution of this project TA01020351 – program ALFA.

  11. Fast Ignition and Stable Combustion of Coarse Coal Particles in a Nonslagging Cyclone Combustor

    Institute of Scientific and Technical Information of China (English)

    BiaoZhou; X.L.Wang; 等

    1995-01-01

    A combustion set-up of an innovative nonalagging cyclone combustor called “Spouting-Cyclone Combustor(SCC)”,,with two-stage combustion,organized in orthogonal vortex flows,was established and the experimental studies on the fast ignition and stable combustion of coarse coal particles in this combustor were carried out.The flame temperature versus ignition time and the practical fast ignition the temperature fields in SCC were obtained.These results whow that it is possible to obtain highly efficient and clean combustion of unground coal particles by using this technology.

  12. Oxidation of Mercury in Products of Coal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Peter Walsh; Giang Tong; Neeles Bhopatkar; Thomas Gale; George Blankenship; Conrad Ingram; Selasi Blavo Tesfamariam Mehreteab; Victor Banjoko; Yohannes Ghirmazion; Heng Ban; April Sibley

    2009-09-14

    Laboratory measurements of mercury oxidation during selective catalytic reduction (SCR) of nitric oxide, simulation of pilot-scale measurements of mercury oxidation and adsorption by unburned carbon and fly ash, and synthesis of new materials for simultaneous oxidation and adsorption of mercury, were performed in support of the development of technology for control of mercury emissions from coal-fired boilers and furnaces. Conversion of gas-phase mercury from the elemental state to water-soluble oxidized form (HgCl{sub 2}) enables removal of mercury during wet flue gas desulfurization. The increase in mercury oxidation in a monolithic V{sub 2}O{sub 5}-WO{sub 3}/TiO{sub 2} SCR catalyst with increasing HCl at low levels of HCl (< 10 ppmv) and decrease in mercury oxidation with increasing NH{sub 3}/NO ratio during SCR were consistent with results of previous work by others. The most significant finding of the present work was the inhibition of mercury oxidation in the presence of CO during SCR of NO at low levels of HCl. In the presence of 2 ppmv HCl, expected in combustion products from some Powder River Basin coals, an increase in CO from 0 to 50 ppmv reduced the extent of mercury oxidation from 24 {+-} 3 to 1 {+-} 4%. Further increase in CO to 100 ppmv completely suppressed mercury oxidation. In the presence of 11-12 ppmv HCl, increasing CO from 0 to {approx}120 ppmv reduced mercury oxidation from {approx}70% to 50%. Conversion of SO{sub 2} to sulfate also decreased with increasing NH{sub 3}/NO ratio, but the effects of HCl and CO in flue gas on SO{sub 2} oxidation were unclear. Oxidation and adsorption of mercury by unburned carbon and fly ash enables mercury removal in a particulate control device. A chemical kinetic mechanism consisting of nine homogeneous and heterogeneous reactions for mercury oxidation and removal was developed to interpret pilot-scale measurements of mercury oxidation and adsorption by unburned carbon and fly ash in experiments at pilot

  13. Structure Based Predictive Model for Coal Char Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Robert Hurt; Joseph Calo; Robert Essenhigh; Christopher Hadad

    2000-12-30

    This unique collaborative project has taken a very fundamental look at the origin of structure, and combustion reactivity of coal chars. It was a combined experimental and theoretical effort involving three universities and collaborators from universities outside the U.S. and from U.S. National Laboratories and contract research companies. The project goal was to improve our understanding of char structure and behavior by examining the fundamental chemistry of its polyaromatic building blocks. The project team investigated the elementary oxidative attack on polyaromatic systems, and coupled with a study of the assembly processes that convert these polyaromatic clusters to mature carbon materials (or chars). We believe that the work done in this project has defined a powerful new science-based approach to the understanding of char behavior. The work on aromatic oxidation pathways made extensive use of computational chemistry, and was led by Professor Christopher Hadad in the Department of Chemistry at Ohio State University. Laboratory experiments on char structure, properties, and combustion reactivity were carried out at both OSU and Brown, led by Principle Investigators Joseph Calo, Robert Essenhigh, and Robert Hurt. Modeling activities were divided into two parts: first unique models of crystal structure development were formulated by the team at Brown (PI'S Hurt and Calo) with input from Boston University and significant collaboration with Dr. Alan Kerstein at Sandia and with Dr. Zhong-Ying chen at SAIC. Secondly, new combustion models were developed and tested, led by Professor Essenhigh at OSU, Dieter Foertsch (a collaborator at the University of Stuttgart), and Professor Hurt at Brown. One product of this work is the CBK8 model of carbon burnout, which has already found practical use in CFD codes and in other numerical models of pulverized fuel combustion processes, such as EPRI's NOxLOI Predictor. The remainder of the report consists of detailed

  14. Research on coal pyrolysis and combustion poly-generation system

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Mengxiang; Cen, Jianmeng; Li, Chao [Zhejiang Univ., Hangzhou (China). Inst. for Thermal Power Engineering] [and others

    2013-07-01

    A new poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal. Coal is first pyrolyzed in a fluidized bed gasifier and produced gas is then purified and used for MeOH or DME production. Tar is collected during purification and can be processed to extract monocyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons and to make liquid fuels by hydrorefining. Semi-coke from the gasifier is burned in a CFB boiler for heat or power generation. A 12MW CFB gas, tar, heat and power poly-generation system was erected by Zhejiang University in cooperation with the Huainan Mining Industry (Group) Co., Ltd. in 2007. The experimental study focused on the two fluidized bed operation and characterization of gas, tar and char yields and compositions. The results showed that the system could operate stable, and produce about 0.12Nm{sup 3}/kg gas with 22MJ/Nm{sup 3} heating value and about 10wt.% tar when pyrolysis temperature between 500 and 600 C. The produced gases were mainly H{sub 2}, CH{sub 4}, N{sub 2}, CO, CO{sub 2}, C{sub 2}H{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 6} and C{sub 3}H{sub 8}. Gas component concentrations were 24.18, 36.29, 7.96, 5.6, 7.84, 11.70 and 3.28%, respectively. The CFB boiler run steadily, whether the gasifier run or not, and produced 12MW power.

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

    Science.gov (United States)

    Warwick, Peter; 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

  16. The Simulation of Influence of Different Coals on the Circulating Fluidized Bed Boiler's Combustion Performance

    Institute of Scientific and Technical Information of China (English)

    Yumei Yong; Qinggang Lu

    2003-01-01

    The combustion performance of the boiler largely depends on the coal type. Lots of experimental research shows that different fuels have different combustion characteristics. It is obvious that fuel will change the whole operating performance of Circulating Fluidized Bed Combustion (CFBC). We know even in a pilot-scale running boiler, the measurement of some parameters is difficult and costly. Therefore, we developed the way of simulation to evaluate the combustion performance of Chinese coals in CFB. The simulation results show that,different coals will result in different coal particle diameter and comminution depending on their mineral component and the change will affect the distribution of ash in CFBC system. In a word, the computational results are in accordance with experimental results qualitatively but there are some differences quantitatively.

  17. Working of spontaneously combustible coal seams with automatic air pressure regulation in the excavation field

    Energy Technology Data Exchange (ETDEWEB)

    Golik, A.S.; Churikov, Yu.V.; Troyan, N.P.

    1980-01-01

    A demonstration is made of the effectiveness of using an automatic air pressure control system during the working of spontaneously combustible coal seams in order to control endogenic fires and gas. 2 figures.

  18. 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.

  19. The development of pollution control technology in coal combustion in China

    Institute of Scientific and Technical Information of China (English)

    XU Xuchang; ZHANG Hu; ZHUO Yuqun; TONG Huiling; WANG Shujuan; LI Yan

    2007-01-01

    The recent development of coal combustion pollution control technologies in China,including desulphurization,denitrification,particulate matters and heavy metals emission control technologies,have been reviewed.The development histories and the advantages of China's self-developed technologies have been introduced in detail.The key points of future research and development in coal combustion pollution control,e.g.,combined emission control and CO2 emission control technologies,have also been discussed.

  20. Characteristics of particulate carbon emissions from real-world Chinese coal combustion.

    Science.gov (United States)

    Zhang, Yuanxun; Schauer, James Jay; Zhang, Yuanhang; Zeng, Limin; Wei, Yongjie; Liu, Yuan; Shao, Min

    2008-07-15

    Particulate matter emissions from a series of different Chinese coal combustion systems were collected and analyzed for elemental and organic carbon (EC, OC), and molecular markers. Emissions from both industrial boilers and residential stoves were investigated. The coal used in this study included anthracite, bituminite, and brown coal, as well as commonly used coal briquettes produced in China for residential coal combustion. Results show significant differences in the contribution of carbonaceous species to particulate mass emissions. Industrial boilers had much higher burn out of carbon yielding particulate matter emissions with much lower levels of OC, EC, and speciated organic compounds, while residential stoves had significantly higher emissions of carbonaceous particulate matter with emission rates of approximately 100 times higher than that of industrial boilers. Quantified organic compounds emitted from industrial boilers were dominated by oxygenated compounds, of which 46-68% were organic acids, whereas the dominate species quantified in the emissions from residential stoves were PAHs (38%) and n-alkanes (20%). An important observation was the fact that emission factors of PAHs and the distribution of hopanoids were different among the emissions from industrial and residential coal combustion even using the same coal for combustion. Although particulate matter emissions from industrial and residential combustion were different in many regards, picene was detected in all samples with detectable OC mass concentrations, which supports the use of this organic tracer for OC from all types of coal combustion. 17alpha(H),21beta(H)-29-norhopane was the predominant hopanoid in coal combustion emissions, which is different from mobile source emissions and may be used to distinguish emissions from these different fossil fuel sources.

  1. Numerical Simulation of Oxy-coal Combustion for a Swirl Burner with EDC Model

    Institute of Scientific and Technical Information of China (English)

    崔凯; 刘冰; 吴玉新; 杨海瑞; 吕俊复; 张海

    2014-01-01

    The characteristics of oxy-coal combustion for a swirl burner with a specially designed preheating chamber are studied numerically. In order to increase the accuracy in the prediction of flame temperature and igni-tion position, eddy dissipation concept (EDC) model with a skeletal chemical reaction mechanism was adopted to describe the combustion of volatile matter. Simulation was conducted under six oxidant stream conditions with dif-ferent O2/N2/CO2 molar ratios:21/79/0, 30/70/0, 50/50/0, 21/0/79, 30/0/70 and 50/0/50. Results showed that O2 en-richment in the primary oxidant stream is in favor of combustion stabilization, acceleration of ignition and increase of maximum flame temperature, while the full substitution of N2 by CO2 in the oxidant stream delays ignition and decreases the maximum flame temperature. However, the overall flow field and flame shapes in these cases are very similar at the same flow rate of the primary oxidant stream. Combustion characteristics of the air-coal is similar to that of the oxy-coal with 30%O2 and 70%CO2 in the oxidant stream, indicating that the rear condition is suitable for retrofitting an air-coal fired boiler to an oxy-coal one. The swirl burner with a specially designed preheating chamber can increase flame temperature, accelerate ignition and enhance burning intensity of pulverized coal under oxy-coal combustion. Also, qualitative experimental validation indicated the burner can reduce the overall NOx emission under certain O2 enrichment and oxy-coal combustion conditions against the air-coal combustion.

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

    Directory of Open Access Journals (Sweden)

    Yibo Tang

    2017-01-01

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

  3. Coal slurry solids/coal fluidized bed combustion by-product mixtures as plant growth media

    Science.gov (United States)

    Darmody, R.G.; Green, W.P.; Dreher, G.B.

    1998-01-01

    Fine-textured, pyritic waste produced by coal cleaning is stored in slurry settling ponds that eventually require reclamation. Conventionally, reclamation involves covering the dewatered coal slurry solids (CSS) with 1.3 m of soil to allow plant growth and prevent acid generation by pyrite oxidation. This study was conducted to determine the feasiblity of a less costly reclamation approach that would eliminate the soil cover and allow direct seeding of plants into amended CSS materials. Potential acidity of the CSS would be neutralized by additions of fluidized-bed combustion by-product (FBCB), an alkaline by-product of coal combustion. The experiment involved two sources of CSS and FBCB materials from Illinois. Birdsfoot trefoil (Lotus corniculatus L.), tall fescue (Festuca arundinacea Schreb.), and sweet clover (Melilotus officinalis (L.) Lam.) were seeded in the greenhouse into pots containing mixtures of the materials. CSS-1 had a high CaCO3:FeS2 ratio and needed no FBCB added to compensate for its potential acidity. CSS-2 was mixed with the FBCB materials to neutralize potential acidity (labeled Mix A and B). Initial pH was 5.6, 8.8, and 9.2 for the CSS-1, Mix A, and Mix B materials, respectively. At the end of the 70-day experiment, pH was 5.9 for all mixtures. Tall fescue and sweet clover grew well in all the treatments, but birdsfoot trefoil had poor emergence and survival. Elevated tissue levels of B, Cd, and Se were found in some plants. Salinity, low moisture holding capacity, and potentially phytotoxic B may limit the efficacy of this reclamation method.

  4. Analysis of coal dust combustion and gasification in the cyclone furnace

    Directory of Open Access Journals (Sweden)

    Zarzycki Robert

    2017-01-01

    Full Text Available This study presents the design and operation of the cyclone furnace fuelled with coal dust. The main function of the furnace is coal dust gasification. The combustible gases that mainly contain CO can be used to feed a pulverized coal-fired boiler. The results of numerical calculations presented in the study demonstrated that cyclone furnace can operate over a wide range of fuel flow rates: from the conditions of coal dust combustion, which ensure maintaining the cyclone furnace in a state of hot reserve to the conditions of coal dust gasification, which allow for production of CO. Gasification process helps control temperature under conditions of elevated oxygen concentration. The results allow for the use of the furnace to improve flexibility and coal dust operation through the reduction in its technological minimum.

  5. Efficient volatile metal removal from low rank coal in gasification, combustion, and processing systems and methods

    Energy Technology Data Exchange (ETDEWEB)

    Bland, Alan E.; Sellakumar, Kumar Muthusami; Newcomer, Jesse D.

    2017-03-21

    Efficient coal pre-processing systems (69) integrated with gasification, oxy-combustion, and power plant systems include a drying chamber (28), a volatile metal removal chamber (30), recirculated gases, including recycled carbon dioxide (21), nitrogen (6), and gaseous exhaust (60) for increasing the efficiencies and lowering emissions in various coal processing systems.

  6. Characterization of Coal Combustion Residues from Electric Utilities Using Wet Scrubbers for Multi-Pollutant Control

    Science.gov (United States)

    This report evaluates changes that may occur to coal combustion residues (CCRs) in response to changes in air pollution control technology at coal-fired power plants, which will reduce emissions from the flue gas stack by transferring pollutants to fly ash and other air pollution...

  7. Membrane-integrated oxy-fuel combustion of coal: Process design and simulation

    NARCIS (Netherlands)

    Chen, Wei; Ham, van der A.G.J.; Nijmeijer, A.; Winnubst, A.J.A.

    2015-01-01

    A membrane-integrated oxy-fuel combustion process is designed and simulated in UniSim Design®. The results of the simulation indicate that a net efficiency of 31.8% is obtained for a coal-fired power plant of 182 MWth (assuming only carbon in the coal), including the compression of CO2 to 100 bar. T

  8. Co-combustion of coal and SRF in an entrained flow reactor: a preliminary study

    DEFF Research Database (Denmark)

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

    2009-01-01

    Investigations on co-firing of SRF with two kinds of bituminous coal were carried out in an entrained flow reactor. The experimental results showed that co-combustion of coal and SRF increased the unburnt carbon in fly ashes. The emissions of NO and SO2 were reduced with an increasing share of SRF...

  9. Approximate-analytical study on thermal preparation and combustion of a coal particle

    Energy Technology Data Exchange (ETDEWEB)

    Salomatov, V.V. [SB RAS, Novosibirsk (Russian Federation). Inst. of Thermophysics; Enkhjargal, Kh. [Mongolian Univ. of Science and Technology, Ulaanbaatar (Mongolia)

    2013-07-01

    The main amount of heat and electricity in the world is produced with application of coal. Following development of power engineering plans application of low-grade coals, including those of new deposits (Salomatov VV, Nature conservation technologies at thermal and atomic power plants, Novosibirsk, NSTU, 2006). Massive Shive-Ovoos open-cast is among such low developed deposits of Mongolia. This deposit requires a set of investigations on thermal preparation and combustion of coal, aimed at extensive and efficient energy utilization. Calculation of flame combustion of coals is based on dependences, which determine the whole combustion process of separate coal particles. For particles of natural coals these processes include complex transformations of organic and mineral parts of coal matrix, heating, devolatization, ignition and burning of coke residue. Such detailed elaboration requires complex physical and mathematical simulation. Five successive stages of thermal preparation and combustion of a coal particle with initial humidity and ash content were distinguished by experimental results: 1. Heating. The particle is heated; the temperature increases, and the mass stays constant. 2. Drying. Liquid inside a wet particle evaporates and mass reduces. 3. Devolatization. 4. Ignition of slightly dried carbon layer by fuel gases. Residual moisture is still kept in the particle. 5. Burning. Two successive conditions are considered: 1. simultaneous burning of dried carbon layer and evaporation; 2. burning of absolutely dry coke residue.

  10. Combustion of low grade fractions of Lubnica coal in fluidized bed

    Directory of Open Access Journals (Sweden)

    Mladenović Milica R.

    2012-01-01

    Full Text Available In this paper a method of examination of fuel suitability for fluidized bed combustion is presented. The research of combustion characteristics of low grade fractions of Lubnica brown coal in the fluidized bed by the aforementioned methodology has been carried out on a laboratory semi-industrial apparatus of 200 kWt. Description of the experimental fluidized bed combustion facility is given, as well as experimental results, with the focus on furnace temperature distribution, in order to determine the location of the zone of intensive combustion. Based on investigation results, which are focused on combustion quality (combustion completion as well as on satisfying the environmental protection criteria, it can be stated that the investigated coal is suitable for burning in bubbling, as well as in circulating fluidized bed.

  11. Slagging characteristics of molten coal ash on silicon-aluminum combustion liners of boiler

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to study the slagging characteristics of boiler combustion liners during pulverized coal stream combustion,the slag samples on the surface of combustion liner were investigated by X-ray diffractometry,scan electron microscopy and energy dispersive X-ray analysis,and the transformation characteristics of the compositions and crystal phases were studied.The results show that the size of slag granules decreases as the slagging temperature increases;the crystallinity of coal ash I reduces to about 48.6% when the temperature is increased up to 1 350 ℃,and that of the coal ash Ⅱ reduces to about 65% when the temperature is increased up to 1 500 ℃;the encroachment of molten coal ash to the combustion liner is strengthened.At the same time,the diffusion and the segregation of the compositions in combustion liners have selectivity,which is in favor of enhancing the content of crystal phases,weakening the conglutination among molten slag compositions and combustion liner,and avoiding yielding big clinkers.But the diffusion of the compositions in combustion liners increases the porosity and decreases the mechanical intensity of combustion liner,and makes the slag encroachment to the liner become more serious.

  12. NOx EMISSIONS PRODUCED WITH COMBUSTION OF POWDER RIVER BASIN COAL IN A UTILITY BOILER

    Energy Technology Data Exchange (ETDEWEB)

    John S. Nordin; Norman W. Merriam

    1997-04-01

    The objective of this report is to estimate the NOx emissions produced when Powder River Basin (PRB) coal is combusted in a utility boiler. The Clean Air Act regulations specify NOx limits of 0.45 lb/mm Btu (Phase I) and 0.40 lb/mm Btu (Phase II) for tangentially fired boilers, and 0.50 lb/mm 13tu (Phase II) and 0.46 lb/mm Btu (Phase II) for dry-bottom wall-fired boilers. The Clean Air Act regulations also specify other limits for other boiler types. Compliance for Phase I has been in effect since January 1, 1996. Compliance for Phase II goes into effect on January 1, 2000. Emission limits are expressed as equivalent NO{sub 2} even though NO (and sometimes N{sub 2}O) is the NOx species emitted during combustion. Regulatory agencies usually set even lower NOx emission limits in ozone nonattainment areas. In preparing this report, Western Research Institute (WRI) used published test results from utilities burning various coals, including PRB coal, using state-of-the art control technology for minimizing NOx emissions. Many utilities can meet Clean Air Act NOx emission limits using a combination of tight combustion control and low-NOx burners and by keeping furnaces clean (i.e., no slag buildup). In meeting these limits, some utilities also report problems such as increased carbon in their fly ash and excessive furnace tube corrosion. This report discusses utility experience. The theory of NOx emission formation during coal combustion as related to coal structure and how the coal is combusted is also discussed. From this understanding, projections are made for NOx emissions when processed PRB coal is combusted in a test similar to that done with other coals. As will be shown, there are a lot of conditions for achieving low NOx emissions, such as tight combustion control and frequent waterlancing of the furnace to avoid buildup of deposits.

  13. Prediction of combustion behavior of coal blends in industrial scale boilers from laboratory scale data

    Energy Technology Data Exchange (ETDEWEB)

    Pisupati, S.V.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States). Coal Utilization Lab.

    1997-12-31

    Thermal analytical techniques such as thermogravimetric analysis (TGA) have been used extensively in characterizing the thermal behavior of coals. Studies have shown that burning profiles are useful for evaluating laboratory scale combustion characteristics. Blending of coals is common in the utility industry to meet emission regulations and lower fuel costs. In this paper, it is shown that using burning profiles to predict carbon burnout of individual coals and blends in a practical combustor is appropriate. (orig.)

  14. Fire Risk Assessment of Some Indian Coals Using Radial Basis Function (RBF) Technique

    Science.gov (United States)

    Nimaje, Devidas; Tripathy, Debi Prasad

    2016-03-01

    Fires, whether surface or underground, pose serious and environmental problems in the global coal mining industry. It is causing huge loss of coal due to burning and loss of lives, sterilization of coal reserves and environmental pollution. Most of the instances of coal mine fires happening worldwide are mainly due to the spontaneous combustion. Hence, attention must be paid to take appropriate measures to prevent occurrence and spread of fire. In this paper, to evaluate the different properties of coals for fire risk assessment, forty-nine in situ coal samples were collected from major coalfields of India. Intrinsic properties viz. proximate and ultimate analysis; and susceptibility indices like crossing point temperature, flammability temperature, Olpinski index and wet oxidation potential method of Indian coals were carried out to ascertain the liability of coal to spontaneous combustion. Statistical regression analysis showed that the parameters of ultimate analysis provide significant correlation with all investigated susceptibility indices as compared to the parameters of proximate analysis. Best correlated parameters (ultimate analysis) were used as inputs to the radial basis function network model. The model revealed that Olpinski index can be used as a reliable method to assess the liability of Indian coals to spontaneous combustion.

  15. Fire Risk Assessment of Some Indian Coals Using Radial Basis Function (RBF) Technique

    Science.gov (United States)

    Nimaje, Devidas; Tripathy, Debi Prasad

    2017-04-01

    Fires, whether surface or underground, pose serious and environmental problems in the global coal mining industry. It is causing huge loss of coal due to burning and loss of lives, sterilization of coal reserves and environmental pollution. Most of the instances of coal mine fires happening worldwide are mainly due to the spontaneous combustion. Hence, attention must be paid to take appropriate measures to prevent occurrence and spread of fire. In this paper, to evaluate the different properties of coals for fire risk assessment, forty-nine in situ coal samples were collected from major coalfields of India. Intrinsic properties viz. proximate and ultimate analysis; and susceptibility indices like crossing point temperature, flammability temperature, Olpinski index and wet oxidation potential method of Indian coals were carried out to ascertain the liability of coal to spontaneous combustion. Statistical regression analysis showed that the parameters of ultimate analysis provide significant correlation with all investigated susceptibility indices as compared to the parameters of proximate analysis. Best correlated parameters (ultimate analysis) were used as inputs to the radial basis function network model. The model revealed that Olpinski index can be used as a reliable method to assess the liability of Indian coals to spontaneous combustion.

  16. Investigation on Pulverized Coal Combustion Behavior by Non-Isothermic Integral Thermogravimetry Method

    Institute of Scientific and Technical Information of China (English)

    QI Cheng-lin; ZHANG Jian-liang; LIN Xiang-hai; LIU Qin-yuan; WANG Xiao-liu

    2011-01-01

    The combustion process of pulverized coal was investigated by non-isothermic integral thermogravimetry. The thermogravimetry curves were fitted by the Coats-Redferm approximation function, and kinetic parameters and characteristic temperatures were obtained. The optimal mixing ratio and particle size can be ascertained. The characteristic temperature of pulverized coal can be obtained from the thermogravimetry curve, and the combustion of coal can be divided into homogeneous and heterogeneous combustion according to the differential thermal analysis curve. The activation energy of a single type of coal ranking from low to high is as follows: bituminous coal, meager-lean coal, and anthracite. In the first mixing method, with more low-price meager-lean coal B replacing high price anthracite A, the activation energy slightly decreases; with more bituminous coal replacing meager-lean coal, total tendency makes a declining of activation. In the later mixing method, with an increase in particle size, a declining activation energy can be seen in total tendency.

  17. A study of oxy-coal combustion with steam addition and biomass blending by thermogravimetric analysis

    OpenAIRE

    Gil Matellanes, María Victoria; Riaza Benito, Juan; Álvarez González, Lucía; Pevida García, Covadonga; Pis Martínez, José Juan; Rubiera González, Fernando

    2011-01-01

    The thermal characteristics of pulverized coal have been studied under oxy-fuel combustion conditions using non-isothermal thermogravimetric analysis (TG). The atmospheres used were 21%O2/79%N2, 21%O2/79%CO2, 30%O2/70%O2, and 35%O2/65%CO2. Coal blends of coal with 10 and 20% of biomass were also studied under these atmospheres. The addition of 10 and 20% of steam was evaluated for the oxy-fuel combustion atmospheres with 21 and 30% of O2 in order to study the effect of the wet recirculation o...

  18. Comparisons between oxy-fuel combustion and IGCC technologies in China coal- energy industry

    OpenAIRE

    Zhao, Xue; Clemente Jul, María del Carmen

    2010-01-01

    A comparison between oxy-fuel combustion plants and IGCC plants has been carried out. Oxy-fuel combustion performs better for the retrofit of exist pulverized coal plants after the evaluation of efficiency, retrofit cost and O&M cost. China is currently and will depending on coal for its energy for a long time. Plenty of PC plants are used in existing power plants due to its lower coal consumption. One way to reduce CO2 emission with CCS is to equip existing power plants with appliance...

  19. Numerical Simulation of NOx Formation in Coal Combustion with Inlet Natural Gas Burning

    Institute of Scientific and Technical Information of China (English)

    张宇; 周力行; 魏小林; 盛宏至

    2005-01-01

    A full two-fluid model of reacting gas-particle flows and coal combustion is used to simulate coal combustion with and without inlet natural gas added in the inlet. The simulation results for the case without natural gas burning is in fair agreement with the experimental results reported in references. The simulation results of different natural gas adding positions indicate that the natural gas burning can form lean oxygen combustion enviroment at the combustor inlet region and the NOx concentration is reduced. The same result can be obtained from chemical equilibrium analysis.

  20. Experimental study on performance that carbon dioxide inhibits coal oxidation and spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    DENG Jun; LI Shi-rong; ZHANG Yan-ni; MU Ying; ZHANG Yang

    2011-01-01

    Adopting oil-bath temperature programming experiment and gas chromatography,CO2's inhibitory performance on spontaneous combustion of Tingnan Coal Mine sample was analyzed.Through temperature rise rate test experiment,the accuracy,stability and reliability of the improved oil-bath temperature programming system applied in this experiment was proved to be superior to the traditional system.Spontaneous combustion characters parameters test of coal sample in pure air was carried out with this system and offered comparison standard for research in next stage.Temperature programming to coal sample was further conducted in oil-bath with different concentration of CO2.Testing results are compared with parameters of concentration of CO,O2,temperature,CO generation rate and O2 consumption rate tested and calculated in previous experiment in pure air.Methods of proportioning between concentration of CO and O2,CO concentration and temperature,CO generation rate and O2 consumption rate were applied to eliminate obstructions from certain external factors such as inlet of CO2; meanwhile influences of CO2 of different concentrations to coal oxidation and spontaneous combustion were investigated.Also CO2 inhibition technique was used in spontaneous combustion prevention in workface No.106 of Tingnan Coal Mine,data collected from which indicate that CO2 performs well in inhibiting coal oxidation and spontaneous combustion.

  1. Advanced coal-fueled gas turbine systems: Subscale combustion testing. Topical report, Task 3.1

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    This is the final report on the Subscale Combustor Testing performed at Textron Defense Systems` (TDS) Haverhill Combustion Laboratories for the Advanced Coal-Fueled Gas Turbine System Program of the Westinghouse Electric Corp. This program was initiated by the Department of Energy in 1986 as an R&D effort to establish the technology base for the commercial application of direct coal-fired gas turbines. The combustion system under consideration incorporates a modular staged, rich-lean-quench, Toroidal Vortex Slogging Combustor (TVC) concept. Fuel-rich conditions in the first stage inhibit NO{sub x} formation from fuel-bound nitrogen; molten coal ash and sulfated sorbent are removed, tapped and quenched from the combustion gases by inertial separation in the second stage. Final oxidation of the fuel-rich gases, and dilution to achieve the desired turbine inlet conditions are accomplished in the third stage, which is maintained sufficiently lean so that here, too, NO{sub x} formation is inhibited. The primary objective of this work was to verify the feasibility of a direct coal-fueled combustion system for combustion turbine applications. This has been accomplished by the design, fabrication, testing and operation of a subscale development-type coal-fired combustor. Because this was a complete departure from present-day turbine combustors and fuels, it was considered necessary to make a thorough evaluation of this design, and its operation in subscale, before applying it in commercial combustion turbine power systems.

  2. Application of Foam-gel Technique to Control CO Exposure Generated During Spontaneous Combustion of Coal in Coal Mines.

    Science.gov (United States)

    Ren, Xing W; Wang, Feng Z; Guo, Qing; Zuo, Zhao B; Fang, Qi S

    2015-01-01

    In China, 47.3% of state-owned coal mines are located in coal seams that are prone to spontaneous combustion. The spontaneous combustion of coal is the main cause of the generation of a large amount of carbon monoxide, which can cause serious health issues to miners. A new technique using foam-gel formation was developed to effectively control the spontaneous combustion of coal. The gel can capture more than 90% of the water in the grout and at the same time the foam can cover dangerous areas in the goaf by stacking and cooling of foam in all directions. In this study, a mechanism of foam-gel formation was introduced and the optimal proportions of additives were defined based on experiments of different foaming properties, gelling time and water loss rate as the main index parameters. The results of a field application in a coal mine promise that this new technique would effectively prevent coal oxidation in the goaf and reduce the generation of carbon monoxide.

  3. Computer controlled measurement of spontaneous combustion in coal stockpiles of the Western Lignite Corporation, Turkey

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The spontaneous combustion event in coal stockpiles is inevitable when appropriate environmental conditions are available.The objective of a computerized measurement system is to measure temperature changes existing in a coal stockpile.In order to achieve this intention, the electrical signal conversion of temperatures sensed by 20 temperature sensors placed in certain points inside the coal stockpile, the transfer of these electrical signals into computer media by using analogue-digital conversion unit after applying necessary filterization and upgrading processes and the record of these information into a database in particular time intervals are provided.Afterwards, the diagrams of these time-temperature data are plotted.With the help of these graphs, the competent company will be able to examine the behavior of coal stockpiles in terms of spontaneous combustion and take necessary precautions against self-combustion beforehand.

  4. Non-linear relationship between combustion kinetic parameters and coal quality

    Institute of Scientific and Technical Information of China (English)

    Jian-guo YANG; Xiao-long ZHANG; Hong ZHAO; Li SHEN

    2012-01-01

    Combustion kinetic parameters (i.e.,activation energy and frequency factor) of coal have been proven to relate closely to coal properties; however,the quantitative relationship between them still requires further study.This paper adopts a support vector regression machine (SVR) to generate the models of the non-linear relationship between combustion kinetic parameters and coal quality.Kinetic analyses on the thermo-gravimetry (TG) data of 80 coal samples were performed to prepare training data and testing data for the SVR.The models developed were used in the estimation of the combustion kinetic parameters of ten testing samples.The predicted results showed that the root mean square errors (RMSEs) were 2.571 for the activation energy and 0.565for the frequency factor in logarithmic form,respectively.TG curves defined by predicted kinetic parameters were fitted to the experimental data with a high degree of precision.

  5. Recognition of Spontaneous Combustion in Coal Mines Based on Genetic Clustering

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Spontaneous combustion is one of the greatest disasters in coal mines. Early recognition is important because it may be a potential inducement for other coalmine accidents. However, early recognition is difficult because of the complexity of different coal mines. Fuzzy clustering has been proposed to incorporate the uncertainty of spontaneous combustion in coal mines and it can give a clear degree of classification of combustion. Because FCM clustering tends to become trapped in local minima, a new approach of fuzzy c-means clustering based on a genetic algorithm is therefore proposed. Genetic algorithm is capable of locating optimal or near optimal solutions to difficult problems. It can be applied in many fields without first obtaining detailed knowledge about correlation. It is helpful in improving the effectiveness of fuzzy clustering in detecting spontaneous combustion. The effectiveness of the method is demonstrated by means of an experiment.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-09-30

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

  7. Preliminary study of trace element emissions and control during coal combustion

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junying; ZHAO Yongchun; DING Feng; ZENG Hancai; ZHENG Chuguang

    2007-01-01

    Hazardous trace element emissions have caused serious harm to human health in China.Several typical high-toxic trace element coals were collected from different districts and were used to investigate the emission characteristics of toxic trace elements (As,Se,Cr,Hg) and to explore preliminary control methods.Coal combustion tests were conducted in several bench-scale furnaces including drop tube furnace (DTF),circulating fluidized bed (CFB) combustion furnace,and fixed-bed combustion furnace.Calcium oxide was used to control the emission of arsenic and selenium.The granular activated carbons (AC) and activatedcarbon fibers (ACF) were used to remove mercury in the flue gas from coal combustion.The chemical composition and trace element contents of ash and particulate matter (PM)were determined by X-ray fluorescence (XRF) spectrometry and inductively coupled plasma-atomic emission spectrometry (ICP-AES),respectively.The speciation and concentration of mercury were investigated using the Ontario-Hydro method.X-ray diffraction spectrometry (XRD) was used to determine the mineral composition of production during combustion experiments.With the addition of a calciumbased sorbent,arsenic concentration in PM1 sharply decreased from 0.25-0.11 mg/m3.In fixed-bed combustion of coal,the retention rates of selenium volatiles were between 11.6% and 50.7% using lime.In the circulating fluidized-bed combustion of coal,the content of selenium in ash from the chimney was reduced to one-fourth of its original value and that in leaching water from the chimney decreased by two orders of magnitude using lime.Calcium-based sorbent is an effective additive to control the emission of As and Se during coal combustion.The emission of chromium is influenced by the occurrence mode of Cr in coal.Chromium emission in PM2.5 during coal combustion is 55.5 and 34.7 μg/m3 for Shenbei coal and mixed Pingdingshan coal,respectively.The adsorptive capacity of granular activated carbon for Hg0 is

  8. The chemical composition of tertiary Indian coal ash and its combustion behaviour – a statistical approach: Part 2

    Indian Academy of Sciences (India)

    Arpita Sharma; Ananya Saikia; Puja Khare; D K Dutta; B P Baruah

    2014-08-01

    In Part 1 of the present investigation, 37 representative Eocene coal samples of Meghalaya, India were analyzed and their physico-chemical characteristics and the major oxides and minerals present in ash samples were studied for assessing the genesis of these coals. Various statistical tools were also applied to study their genesis. The datasets from Part 1 used in this investigation (Part 2) show the contribution of major oxides towards ash fusion temperatures (AFTs). The regression analysis of high temperature ash (HTA) composition and initial deformation temperature (IDT) show a definite increasing or decreasing trend, which has been used to determine the predictive indices for slagging, fouling, and abrasion propensities during combustion practices. The increase or decrease of IDT is influenced by the increase of Fe2O3, Al2O3, SiO2, and CaO, respectively. Detrital-authigenic index (DAI) calculated from the ash composition and its relation with AFT indicates Sialoferric nature of these coals. The correlation analysis, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were used to study the possible fouling, slagging, and abrasion potentials in boilers during the coal combustion processes. A positive relationship between slagging and heating values of the coal has been found in this study.

  9. 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).

  10. 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.

  11. Co-combustion of peanut hull and coal blends: Artificial neural networks modeling, particle swarm optimization and Monte Carlo simulation.

    Science.gov (United States)

    Buyukada, Musa

    2016-09-01

    Co-combustion of coal and peanut hull (PH) were investigated using artificial neural networks (ANN), particle swarm optimization, and Monte Carlo simulation as a function of blend ratio, heating rate, and temperature. The best prediction was reached by ANN61 multi-layer perception model with a R(2) of 0.99994. Blend ratio of 90 to 10 (PH to coal, wt%), temperature of 305°C, and heating rate of 49°Cmin(-1) were determined as the optimum input values and yield of 87.4% was obtained under PSO optimized conditions. The validation experiments resulted in yields of 87.5%±0.2 after three replications. Monte Carlo simulations were used for the probabilistic assessments of stochastic variability and uncertainty associated with explanatory variables of co-combustion process.

  12. Co-combustion of coal and sewage sludge: chemical and ecotoxicological properties of ashes.

    Science.gov (United States)

    Barbosa, Rui; Lapa, Nuno; Boavida, Dulce; Lopes, Helena; Gulyurtlu, Ibrahim; Mendes, Benilde

    2009-10-30

    The co-combustion of sewage sludge (SS) and coal is widely used for the treatment and thermal valorization of SS produced in wastewater treatment plants. The chemical and ecotoxicological properties of the ashes produced in this thermal treatment have not been fully studied. Two combustion tests were performed in a fluidized bed combustor. Colombian coal was used as fuel in test A. A blend (1+1) of this coal and a stabilized SS (Biogran) was used in a second test B. Samples of the bottom and fly ashes trapped in two sequential cyclones were collected. The characterization of the ashes was focused on two main aspects: (1) the bulk content of a set of metals and (2) the characterization of eluates produced according to the European Standard leaching test EN 12457-2. The eluates were submitted to an ecotoxicological characterization for two bio-indicators. In what concerns the bulk content of ashes, both combustion tests have produced ashes with different compositions. The ashes formed during the co-combustion test have shown higher concentrations of metals, namely Cr, Cu, Ni, Pb, Zn and Fe for all ashes. The leaching test has shown low mobility of these elements from the by-products produced during the combustion and co-combustion tests. Cr and Cr(VI) were mainly detected in the eluates of the 1st cyclone ashes produced in both combustion tests and in the 2nd cyclone ashes produced in the co-combustion test. Considering the ecotoxicity assays, the eluates of bottom and fly ashes for both combustion and co-combustion tests have shown low ecotoxic levels. The micro-crustacean Daphnia magna was generally more sensitive than the bacterium Vibrio fischeri. CEMWE criterion has allowed to classify the bottom ashes for both combustion and co-combustion tests as non-toxic residues and the fly ashes collected in both cyclones as toxic.

  13. 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.

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

    Science.gov (United States)

    Borrok, David M; Gieré, Reto; Ren, Minghua; Landa, Edward R

    2010-12-01

    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.

  15. Short-term influence of coal mine reclamation using coal combustion residues on groundwater quality.

    Science.gov (United States)

    Cheng, Chin-Min; Amaya, Maria; Butalia, Tarunjit; Baker, Robert; Walker, Harold W; Massey-Norton, John; Wolfe, William

    2016-11-15

    Two full-scale coal mine reclamation projects using coal combustion residues (CCRs) were recently carried out at highwall pit complexes near the Conesville and Cardinal coal-fired power plants owned by American Electric Power. The environment impacts of the reclamation projects were examined by regularly monitoring the leaching characteristics of the backfilling CCRs and the water quality of the uppermost aquifers underlying the sites. With over five years of field monitoring, it shows that the water quality at both demonstration sites had changed since the reclamation began. By analyzing the change of the hydrogeochemical properties, it was concluded that the water quality impact observed at the Conesville Five Points site was unlikely due to the seepage of FGD material leachates. Reclamation activities, such as logging, grading, and dewatering changed the hydrogeological conditions and resulted in the observed water quality changes. The same hydrogeological effect on water quality was also found at the Cardinal Star Ridge site during the early stage of the reclamation (approximately the first 22months). Subsequent measurements showed the water quality to be strongly influenced by the water in the reclaimed highwall pit. Despite the changes to the water quality, the impacts are insignificant and temporary. None of the constitutes showed concentration levels higher than the regulatory leaching limits set by the Ohio Department of Natural Resources' Division of Mineral Resources Management for utilizing CCRs in mined land reclamation. Compared to the local aquifers, the concentrations of eleven selected constituents remained at comparable levels throughout the study period. There are four constituents (i.e., As, Be, Sb, and Tl) that exceeded their respective MCLs after the reclamation began. These detections were found shortly (i.e., within 2years) after the reclamation began and decreased to the levels either lower than the respective detection limits or similar to

  16. Development and evaluation of coal/water mixture combustion technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Scheffee, R.S.; Rossmeissl, N.P.; Skolnik, E.G.; McHale, E.T.

    1981-08-01

    The objective was to advance the technology for the preparation, storage, handling and combustion of highly-loaded coal/water mixtures. A systematic program to prepare and experimentally evaluate coal/water mixtures was conducted to develop mixtures which (1) burn efficiently using combustion chambers and burners designed for oil, (2) can be provided at a cost less than that of No. 6 oil, and (3) can be easily transported and stored. The program consisted of three principal tasks. The first was a literature survey relevant to coal/water mixture technology. The second involved slurry preparation and evaluation of rheological and stability properties, and processing techniques. The third consisted of combustion tests to characterize equipment and slurry parameters. The first task comprised a complete search of the literature, results of which are tabulated in Appendix A. Task 2 was involved with the evaluation of composition and process variables on slurry rheology and stability. Three bituminous coals, representing a range of values of volatile content, ash content, and hardness were used in the slurries. Task 3 was concerned with the combustion behavior of coal/water slurry. The studies involved first upgrading of an experimental furnace facility, which was used to burn slurry fuels, with emphasis on studying the effect on combustion of slurry properties such as viscosity and particle size, and the effect of equipment parameters such as secondary air preheat and atomization.

  17. 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.

  18. State-of-the-art combustion controls CO{sub 2} emissions from coal : part 2

    Energy Technology Data Exchange (ETDEWEB)

    Farzan, H.; Vecci, S.; McDonald, D.; McCauley, K [Babcock and Wilcox Canada Ltd., Toronto, ON (Canada); Pranda, P.; Varagani, R.; Gautier, F.; Tranier, J.P.; Perrin, N. [Air Liquide Canada Inc., Montreal, PQ (Canada)

    2007-11-15

    Power plant operators use the cost of electricity (COE) as a way to compare different generating technologies, including those that require investment into costly carbon management. This article addressed issues regarding the goals that management sets and how they are measured in terms of economic profit. It was noted that power companies are not as likely to invest in carbon management technologies until there is assurance that competing power companies will do the same, or until incentives encourage it. A few power companies are well located to provide carbon dioxide for enhanced oil recovery, but others intend to master the technology of carbon management in preparation for a time when it may be a key competitive advantage. This article described key elements of oxy-coal combustion feasibility and competitiveness. This included oxygen production and specification for oxy-coal combustion. It was shown that for oxy-coal combustion plants, the best solution to purify the flue gas from the boiler is a lower temperature partial condensation scheme as soon as oxygen removal is considered. Oxy-coal combustion technology for retrofitting coal-fired boilers was also presented. A Clean Environment Development Facility (CEDF) project in Ohio for oxy-coal combustion was described along with the proposed development of a 300 MWe commercial oxy-coal boiler by SaskPower, Babcock and Wilcox Canada and AL. It was concluded that the ability to capture carbon dioxide from power plants is feasible in advanced modes of current technology and with new technology under development. However, oxy-combustion technology requires introducing new equipment to power plants, such as the air separation unit (ASU) and the carbon dioxide central processing unit (CPU). 1 tab., 5 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-03-01

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

  20. An important missing source of atmospheric carbonyl sulfide: Domestic coal combustion

    Science.gov (United States)

    Du, Qianqian; Zhang, Chenglong; Mu, Yujing; Cheng, Ye; Zhang, Yuanyuan; Liu, Chengtang; Song, Min; Tian, Di; Liu, Pengfei; Liu, Junfeng; Xue, Chaoyang; Ye, Can

    2016-08-01

    Carbonyl sulfide (COS), carbon monoxide (CO), and sulfur dioxide (SO2) emissions generated from prevailing domestic coal stoves fueled with raw bituminous coal were studied under alternation cycles of flaming and smoldering combustion. The measurements in the laboratory and the farmer's house indicated that COS and CO emissions mainly occurred under the condition of flame extinguishment after coal loading, whereas SO2 emissions were mainly generated through combustion with flame. The COS emission factors for the domestic stoves in the laboratory and the farmer's house were recorded as 0.57 ± 0.10 g COS kg-1 and 1.43 ± 0.32 g COS kg-1, being approximately a factor of 50 and 125 greater than that generated from coal power plants, respectively. Based on the COS emission factors measured in this study, COS emission from only domestic coal combustion in China would be at least 30.5 ± 5.6 Gg S yr-1 which was 1 magnitude greater than the current COS estimation from the total coal combustion in China.

  1. 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.

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

    Science.gov (United States)

    Konopa, Stephanie Lucero; Mulholland, James A; Realff, Matthew J; Lemieux, Paul M

    2008-08-01

    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 (SO2), 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 particle-board combustion, consistent with its higher nitrogen content. SO2 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.

  3. Development and testing of commercial-scale, coal-fired combustion systems: Phase III. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Based on studies that indicated a large potential for significantly increased coal-firing in the commercial sector, the U.S. Department of Energy`s Pittsburgh Energy Technology Center (PETC) sponsored a multi-phase development effort for advanced coal combustion systems. This Final Report presents the results of the last phase (Phase III) of a project for the development of an advanced coal-fired system for the commercial sector of the economy. The project performance goals for the system included dual-fuel capability (i.e., coal as primary fuel and natural gas as secondary fuel), combustion efficiency exceeding 99 percent, thermal efficiency greater than 80 percent, turndown of at least 3:1, dust-free and semi-automatic dry ash removal, fully automatic start-up with system purge and ignition verification, emissions performance exceeding New Source Performance Standards (NSPS) and approaching those produced by oil-fired, Commercial-sized units, and reliability, safety, operability, maintainability, and service life comparable to oil-fired units. The program also involved a site demonstration at a large facility owned by Striegel Supply Company, a portion of which was leased to MTCI. The site, mostly warehouse space, was completely unheated and the advanced coal-fired combustion system was designed and sized to heat this space. Three different coals were used in the project, one low and one high sulfur pulverized Pittsburgh No. 8 coal, and a micronized low volatile, bituminous coal. The sorbents used were Pfizer dolomitic limestone and an Anvil lime. More than 100 hours of screening test`s were performed to characterize the system. The parameters examined included coal firing rate, excess air level, ash recycle rate, coal type, dolomitic limestone feed rate, and steam injection rate. These tests indicated that some additional modifications for coal burning in the system were required.

  4. Annual Change Detection by ASTER TIR Data and an Estimation of the Annual Coal Loss and CO2 Emission from Coal Seams Spontaneous Combustion

    Directory of Open Access Journals (Sweden)

    Xiaomin Du

    2014-12-01

    Full Text Available Coal fires, including both underground and coal waste pile fires, result in large losses of coal resources and emit considerable amounts of greenhouse gases. To estimate the annual intensity of greenhouse gas emissions and the loss of coal resources, estimating the annual loss from fire-influenced coal seams is a feasible approach. This study assumes that the primary cause of coal volume loss is subsurface coal seam fires. The main calculation process is divided into three modules: (1 Coal fire quantity calculations, which use change detection to determine the areas of the different coal fire stages (increase/growth, maintenance/stability and decrease/shrinkage. During every change detections, the amount of coal influenced by fires for these three stages was calculated by multiplying the coal mining residual rate, combustion efficiency, average thickness and average coal intensity. (2 The life cycle estimate is based on remote sensing long-term coal fires monitoring. The life cycles for the three coal fire stages and the corresponding life cycle proportions were calculated; (3 The diurnal burnt rates for different coal fire stages were calculated using the CO2 emission rates from spontaneous combustion experiments, the coal fire life cycle, life cycle proportions. Then, using the fire-influenced quantity aggregated across the different stages, the diurnal burn rates for the different stages and the time spans between the multi-temporal image pairs used for change detection, we estimated the annual coal loss to be 44.3 × 103 tons. After correction using a CH4 emission factor, the CO2 equivalent emissions resulting from these fires was on the order of 92.7 × 103 tons. We also discovered that the centers of these coal fires migrated from deeper to shallower parts of the coal seams or traveled in the direction of the coal seam strike. This trend also agrees with the cause of the majority coal fires: spontaneous combustion of coalmine goafs.

  5. National coal utilization assessment: modeling long-term coal production with the Argonne coal market model

    Energy Technology Data Exchange (ETDEWEB)

    Dux, C.D.; Kroh, G.C.; VanKuiken, J.C.

    1977-08-01

    The Argonne Coal Market Model was developed as part of the National Coal Utilization Assessment, a comprehensive study of coal-related environmental, health, and safety impacts. The model was used to generate long-term coal market scenarios that became the basis for comparing the impacts of coal-development options. The model has a relatively high degree of regional detail concerning both supply and demand. Coal demands are forecast by a combination of trend and econometric analysis and then input exogenously into the model. Coal supply in each region is characterized by a linearly increasing function relating increments of new mine capacity to the marginal cost of extraction. Rail-transportation costs are econometrically estimated for each supply-demand link. A quadratic programming algorithm is used to calculate flow patterns that minimize consumer costs for the system.

  6. Assessing potential fire hazard presented by coal pillars and blocks

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Eh.M.; Zakharov, E.I.; Shklover, S.V.; Panferova, I.V.

    1985-11-01

    An improved method is presented for predicting fire hazard in coal masses based on analytical studies of spontaneous combustion of coal. The origins and development of endogenic fires in coal pillars and blocks of coal in the roofs of underground roadways are described; particular reference is made to conditions in the Podmoskovnyi coalfield. Spontaneous combustion risk is greatest when spontaneous heatings progress from the stage of slow, low-temperature oxidation to the medium-temperature stage, which immediately precedes ignition and the characteristic rapid rise in heat generation. The critical temperature threshold between the two stages is studied as the pointer to spontaneous combustion risk. Factors also considered are: non-uniform oxidation of the coal in the pillar or block; coal fissure oxygen content; spasmodic fluctuations in the oxidation process once critical temperature is reached; thermal conductivity of coal and rock strata; roadway air temperature. 5 references.

  7. A comparison of co-combustion characteristics of coal with wood and hydrothermally treated municipal solid waste.

    Science.gov (United States)

    Muthuraman, Marisamy; Namioka, Tomoaki; Yoshikawa, Kunio

    2010-04-01

    In this work, thermogravimetric analysis was used to investigate the co-combustion characteristics of wood and municipal solid waste (MSW) with Indian coal. Combustion characteristics like volatile release, ignition were studied. Wood presented an enhanced reaction rate reflecting its high volatile and low ash contents, while MSW enhanced ignition behavior of Indian coal. The results indicate that blending of both, wood and MSW improves devolatization properties of coal. Significant interaction was detected between wood and Indian coal, and reactivity of coal has improved upon blending with wood. On the other hand, MSW shows a good interaction with Indian coal leading to significant reduction in ignition temperature of coal and this effect was more pronounced with higher blending ratio of MSW. Hence MSW blending could more positively support the combustion of low quality Indian coal as compared to wood, due to its property of enhancement of ignition characteristics.

  8. MUTATION SPECTRA OF SMOKY COAL COMBUSTION EMMISSIONS IN SALMONELLA REFLECTS THE TP53 AND KRAS MUTATIONS IN LUNG TUMORS FROM SMOKY COAL EXPOSED INDIVIDUALS

    Science.gov (United States)

    Mutation Spectra of Smoky Coal Combustion Emissions in Salmonella Reflect the TP53and KRAS Mutations in Lung Tumors from Smoky Coal-Exposed Individuals Abstract Nonsmoking women in Xuan Wei County, Yunnan Province, China who use smoky coal for cooking and h...

  9. 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...

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

    Institute of Scientific and Technical Information of China (English)

    JIN Jing; ZHANG Zhongxiao; LI Ruiyang

    2007-01-01

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

  11. Investigation of co-combustion of coal and olive cake in a bubbling fluidized bed with secondary air injection

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-15

    In this study, a bubbling fluidized bed of 102 mm inside diameter and 900 mm height was used to burn olive cake and coal mixtures. Tuncbilek lignite coal was used together with olive cake for the co-combustion tests. Combustion performances and emission characteristics of olive cake and coal mixtures were investigated. Various co-combustion tests of coal with olive cake were conducted with mixing ratios of 25%, 50%, and 75% of olive cake by weight in the mixture. Operational parameters (excess air ratio, secondary air injection) were changed and variation of pollutant concentrations and combustion efficiency with these operational parameters were studied. The results were compared with that of the combustion of olive cake and coal. Flue gas concentrations of O{sub 2}, CO, SO{sub 2}, NOx, and total hydrocarbons (CmHn) were measured during combustion tests. For the setup used in this study, the optimum operating conditions with respect to NOx and SO{sub 2} emissions were found to be 1.35 for excess air ratio, and 30 L/min for secondary air flowrate for the combustion of 75 wt% olive cake and 25 wt% coal mixture. The highest combustion efficiency of 99.8% was obtained with an excess air ratio of 1.7, secondary air flow rate of 40 L/min for the combustion of 25 wt% olive cake and 75 wt% coal mixture. 11 refs., 8 figs., 3 tabs.

  12. 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.

  13. [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.

  14. Numerical study of bituminous coal combustion in a boiler furnace with bottom blowing

    Science.gov (United States)

    Zroychikov, N. A.; Kaverin, A. A.

    2016-11-01

    Results obtained by the numerical study of a solid fuel combustion scheme with bottom blowing using Ekibastuz and Kuznetsk bituminous coals of different fractional makeup are presented. Furnace chambers with bottom blowing provide high-efficiency combustion of coarse-grain coals with low emissions of nitrogen oxides. Studying such a combustion scheme, identification of its technological capabilities, and its further improvement are topical issues. As the initial object of study, we selected P-57-R boiler plant designed for burning of Ekibastuz bituminous coal in a prismatic furnace with dry-ash (solid slag) removal. The proposed modernization of the furnace involves a staged air inflow under the staggered arrangement of directflow burners (angled down) and bottom blowing. The calculation results revealed the specific aerodynamics of the flue gases, the trajectories of solid particles in the furnace chamber, and the peculiarities of the fuel combustion depending on the grinding fineness. It is shown that, for coal grinding on the mill, the overall residue on the screen plate of 90 µm ( R 90 ≤ 27% for Ekibastuz coal and R 90 ≤ 15% for Kuznetsk coal) represents admissible values for fuel grind coarsening in terms of economic efficiency and functional reliability of a boiler. The increase in these values leads to the excess of regulatory heat losses and unburned combustible losses. It has been established that the change in the grade of the burned coal does not significantly affect the flow pattern of the flue gases, and the particles trajectory is essentially determined by the elemental composition of the fuel.

  15. Emission factors of gaseous carbonaceous species from residential combustion of coal and crop residue briquettes

    Institute of Scientific and Technical Information of China (English)

    Qin WANG; Chunmei GENG; Sihua LU; Wentai CHEN; Min SHAO

    2013-01-01

    Experiments were performed to measure the emission factors (EFs) of gaseous carbonaceous species, such as CO2, CO, CH4, and non-methane volatile organic compounds (NMVOCs), from the combustion of five types of coal of varying organic maturity and two types of biomass briquettes under residential burning conditions. Samples were collected in stainless steel canisters and 2,4- dinitrophenylhydrazine (DNPH) cartridges and were analyzed by GC FID/MS and HPLC, respectively. The EFs from crop residue briquette burning were generally higher than those from coals, with the exception of CO2. The dominant NMVOC species identified in coal smoke were carbonyls (41.7%), followed by C2 unsaturated hydrocarbons (29.1%) and aromatics (12.1%), while C2 unsaturated hydrocarbons were the dominant species (68.9%) emitted from the combustion of crop residue briquettes, followed by aromatics (14.4%). A comparison of burning normal crop residues in stoves and the open field indicated that briquettes emitted a larger proportion of ethene and acetylene. Both combustion efficiency and coal organic maturity had a significant impact on NMVOC EFs from burning coal: NMVOC emissions increased with increasing coal organic maturity but decreased as the combustion efficiency improved. Emissions from the combustion of crop residue briquettes from stoves occurred mainly during the smoldering process, with low combustion efficiency. Therefore, an improved stove design to allow higher combustion efficiency would be beneficial for reducing emissions of carbonaceous air pollutants.

  16. Investigation of the spraying mechanism and combustion of the suspended coal fuel

    Directory of Open Access Journals (Sweden)

    Murko Vasiliy I.

    2015-01-01

    Full Text Available This paper continues the earlier one [1]. It presents the results of the suspended coal fuel spraying with pneumo-mechanical sprayers followed by the fuel combustion in a vortex furnace. It is shown that, during the spraying, two qualitatively different systems of drops are forming. The first one with the “drops” diameter above 80 - 100 mm is presented by coal particles, the other - by water-coal drops. Different dynamics of temperature variation of the coal particle and WCF drops during their combustion is founded. The residence time of the burning particles and WCF drops in the vortex furnace is proportional to their diameter, which permits to provide their effective burn-off.

  17. Sulfur retention by ash during coal combustion. Part II. A model of the process

    Energy Technology Data Exchange (ETDEWEB)

    Vasilije Manovic; Borislav Grubor; Mladen Ilic; Branimir Jovancicevic

    2003-07-01

    An overall model for sulfur self-retention in ash during coal particle combustion is developed in this paper. It is assumed that sulfur retention during char combustion occurs due to the reaction between SO{sub 2} and CaO in the form of uniformly distributed non-porous grains. Parametric analysis shows that the process of sulfur self-retention is limited by solid diffusion through the non-porous product layer formed on the CaO grains and that the most important coal characteristics which influence sulfur self-retention are coal rank, content of sulfur forms, molar Ca/S ratio and particle radius. A comparison with the experimentally obtained values in a FB reactor showed that the model can adequately predict the kinetics of the process, the levels of the obtained values of the SSR efficiencies, as well as the influence of temperature and coal particle size.

  18. Sulfur retention by ash during coal combustion. Part II. A model of the process

    Directory of Open Access Journals (Sweden)

    BRANIMIR JOVANCICEVIC

    2003-03-01

    Full Text Available An overall model for sulfur self-retention in ash during coal particle combustion is developed in this paper. It is assumed that sulfur retention during char combustion occurs due to the reaction between SO2 and CaO in the form of uniformly distributed non-porous grains. Parametric analysis shows that the process of sulfur self-retention is limited by solid difussion through the non-porous product layer formed on the CaO grains and that the most important coal characteristics which influence sulfur self-retention are coal rank, content of sulfur forms, molar Ca/S ratio and particle radius. A comparison with the experimentally obtained values in a FB reactor showed that the model can adequately predict the kinetics of the process, the levels of the obtained values of the SSR efficiencies, as well as the influence of temperature and coal particle size.

  19. Effects of fractal surface on rheological behavior and combustion kinetics of modified brown coal water slurries

    Institute of Scientific and Technical Information of China (English)

    Zhifang Gao; Shuquan Zhu; Mingdong Zheng; Zhaojin Wu; Huihong Lu; Weiming Liu

    2015-01-01

    The paper reports the effects of surface fractal structures on the rheological behavior and combustion kinetics of raw brown coal and three modified coal water slurries (CWSs). The results show that the fractal structures and physicochemical properties of samples are dependent on various modification processes. The apparent viscosities of the coal water slurries increase with increasing surface fractal dimensions (D), especially with decreasing shear rates. Fur-thermore, it has been proved that the ignition temperatures and apparent activation energies of modified CWSs are lower than that of raw coal water slurry. Compared with the traditional qualitative analysis of the effect of pore structures on CWSs properties, D can more efficiently indicate the quantificational effect of pore structures on the rheological behavior and combustion kinetics of CWSs.

  20. Deposit Formation during Coal-Straw Co-Combustion in a Utility PF-Boiler

    DEFF Research Database (Denmark)

    Andersen, Karin Hedebo

    1998-01-01

    This Ph.D. thesis reports the research on ash deposit formation in the convective pass of a utility PF-boiler during co-combustion of coal and straw. The work was based on experimental results from a two-year full scale demonstration programme at the Studstrup Power Station, Unit 1 (MKS1), owned...... by Midtkraft Energy Company. Primarily the results from the deposition trials, but also related experimental data were used in the evaluation. In connection with the evaluation of the probe deposits collected, a visual analyses system was developed, where the physical appearence of the deposit is evaluated...... to full load) during experiments with COCERR coal. The downstream deposits were in all cases powdery deposits, which were not well attached to the probes and could easily be removed. When utilising USILI2 coal with higher content of Fe and S than COCERR, the main effect was observed for coal combustion...

  1. 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.

  2. Comparative study of cogasification and co-combustion of communal sewage sludge in brown coal fuelled plants; Vergleich der Mitvergasung und Mitverbrennung kommunaler Klaerschlaemme in braunkohlegefeuerten Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Schiffer, H.P.; Bierbaum, K.; Adlhoch, W.; Thomas, G. [Rheinbraun AG, Koeln (Germany)

    1996-12-31

    Co-combustion and cogasification of sewage sludge in brown coal fuelled plants are compared, and an economic assessment is made. (ABI) [Deutsch] Die Mitverbrennung und Mitvergasung von Klaerschlamm in braunkohlegefeuerten Anlagen werden verglichen und auf ihre Wirtschaftlichkeit hin untersucht. (ABI)

  3. Temperature Trends in Coal Char Combustion under Oxy-fuel Conditions for the Determination of Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Samira [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hecht, Ethan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    Oxy-fuel combustion technology with carbon capture and storage could significantly reduce global CO2 emissions, a greenhouse gas. Implementation can be aided by computational fluid dynamics (CFD) simulations, which require an accurate understanding of coal particle kinetics as they go through combustion in a range of environments. To understand the kinetics of pulverized coal char combustion, a heated flow reactor was operated under a wide range of experimental conditions. We varied the environment for combustion by modifying the diluent gas, oxygen concentration, gas flow rate, and temperature of the reactor/reacting gases. Measurements of reacting particle temperatures were made for a sub-bituminous and bituminous coal char, in environments with CO2 or N2 as the diluent gas, with 12, 24, and 36 vol-% oxygen concentration, at 50, 80, 100, and 200 standard liters per minute flowing through the reactor, reactor temperatures of 1200, 1400 K, at pressures slightly above atmospheric. The data shows consistent increasing particle temperature with increased oxygen concentration, reactor temperature and higher particle temperatures for N2 diluent than CO2. We also see the effects of CO2 gasification when different ranks of coal are used, and how the reduction in the temperature due to the CO2 diluent is greater for the coal char that has higher reactivity. Quantitative measurements for temperature are not yet complete due to ongoing calibration of detection systems.

  4. 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.

  5. Co-combustion of solid recovered fuels in coal-fired power plants.

    Science.gov (United States)

    Thiel, Stephanie; Thomé-Kozmiensky, Karl Joachim

    2012-04-01

    Currently, in ten coal-fired power plants in Germany solid recovered fuels from mixed municipal waste and production-specific commercial waste are co-combusted and experiments have been conducted at other locations. Overall, in 2010 approximately 800,000 tonnes of these solid recovered fuels were used. In the coming years up to 2014 a slight decline in the quantity of materials used in co-combustions is expected. The co-combustion activities are in part significantly influenced by increasing power supply from renewable sources of energy and their impact on the regime of coal-fired power plants usage. Moreover, price trends of CO₂ allowances, solid recovered fuels as well as imported coal also have significant influence. In addition to the usage of solid recovered fuels with biogenic content, the co-combustion of pure renewable biofuels has become more important in coal-fired power plants. The power plant operators make high demands on the quality of solid recovered fuels. As the operational experience shows, a set of problems may be posed by co-combustion. The key factors in process engineering are firing technique and corrosion. A significant ecological key factor is the emission of pollutants into the atmosphere. The results of this study derive from research made on the basis of an extensive literature search as well as a survey on power plant operators in Germany. The data from operators was updated in spring 2011.

  6. Carbon-Centered Free Radicals in Particulate Matter Emissions from Wood and Coal Combustion

    OpenAIRE

    2009-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used to measure the free radicals in the particulate matter (PM) emissions from wood and coal combustion. The intensity of radicals in PM dropped linearly within two months of sample storage and stabilized after that. This factor of storage time was adjusted when comparing radical intensities among different PM samples. An inverse relationship between coal rank and free radical intensities in PM emissions was observed, which was in contra...

  7. Experimental research of sewage sludge with coal and biomass co-combustion, in pellet form.

    Science.gov (United States)

    Kijo-Kleczkowska, Agnieszka; Środa, Katarzyna; Kosowska-Golachowska, Monika; Musiał, Tomasz; Wolski, Krzysztof

    2016-07-01

    Increased sewage sludge production and disposal, as well as the properties of sewage sludge, are currently affecting the environment, which has resulted in legislation changes in Poland. Based on the Economy Minister Regulation of 16 July 2015 (Regulation of the Economy Minister, 2015) regarding the criteria and procedures for releasing wastes for landfilling, the thermal disposal of sewage sludge is important due to its gross calorific value, which is greater than 6MJ/kg, and the problems that result from its use and application. Consequently, increasingly restrictive legislation that began on 1 January 2016 was introduced for sewage sludge storage in Poland. Sewage sludge thermal utilisation is an attractive option because it minimizes odours, significantly reduces the volume of starting material and thermally destroys the organic and toxic components of the off pads. Additionally, it is possible that the ash produced could be used in different ways. Currently, as many as 11 plants use sewage sludge as fuel in Poland; thus, this technology must be further developed in Poland while considering the benefits of co-combustion with other fuels. This paper presents the results of experimental studies of the mechanisms and kinetics of sewage sludge, coal and biomass combustion and their co-combustion in spherical-pellet form. Compared with biomass, a higher temperature is required to ignite sewage sludge by flame. The properties of biomass and sewage sludge result in the intensification of the combustion process (by fast ignition of volatile matter). In contrast to coal, a combustion of sewage sludge is determined not only burning the char, but also the combustion of volatiles. The addition of sewage sludge to hard coal and lignite shortens combustion times compared with coal, and the addition of sewage sludge to willow Salix viminalis produces an increase in combustion time compared with willow alone.

  8. Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix A, Part 1. Coal preparation and cleaning assessment study

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-12-01

    This report evaluates the state of the art and effectiveness of physical coal cleaning as a potential strategy for controlling SO/sub x/ emissions in coal fired power generation. Coal properties which are significantly altered by physical coal cleaning were determined. The effects of the changes in properties as they relate to pulverized coal firing, fluidized bed combustion and low Btu gasification for combined cycle powered generation were studied. Available coal washability data were integrated by computer with U.S. coal reserve data. Approximately 18% of the demonstrated coal reserve were matched with washability data. Integrated data appear in the Appendix. Current coal preparation practices were reviewed. Future trends were determined. Five process flow sheets representing increasing levels of cleaning sophistication were prepared. The clean product from each flow sheet will meet U.S. EPA New Source Performance Standards. Capital and operating costs for each case were estimated. Environmental control technology and environmental impact associated with current coal preparation and cleaning operations were assessed. Physical coal cleaning is widely practiced today. Where applicable it represents the least expensive method of coal sulfur reduction. Developmental physical and chemical coal cleaning processes were studied. The chemical methods have the advantage of being able to remove both pyritic sulfur and organic sulfur present in the coal matrix. Further R and D efforts will be required before commercialization of these processes.

  9. Development of Energy Efficient Technologies for Burning Coal in Modern Thermal Power Plants and Efficiency Assessment Tools

    Science.gov (United States)

    Dubrovskiy, Vitali; Zubova, Marina; Sedelnikov, Nikolai; Dihnova, Anna

    2016-02-01

    Universal ecological energy-efficient burner was described. The burner allows to burn different types of coal and lignite without the use of fuel oil for kindling the boiler. Efficiency assessment tools of the introduction of the burner for combustion of coal in modern thermal power plants were given.

  10. Development of Energy Efficient Technologies for Burning Coal in Modern Thermal Power Plants and Efficiency Assessment Tools

    Directory of Open Access Journals (Sweden)

    Dubrovskiy Vitali

    2016-01-01

    Full Text Available Universal ecological energy-efficient burner was described. The burner allows to burn different types of coal and lignite without the use of fuel oil for kindling the boiler. Efficiency assessment tools of the introduction of the burner for combustion of coal in modern thermal power plants were given.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

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

    Science.gov (United States)

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

    1998-01-01

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

  13. Environmental, physical and structural characterisation of geopolymer matrixes synthesised from coal (co-)combustion fly ashes.

    Science.gov (United States)

    Alvarez-Ayuso, E; Querol, X; Plana, F; Alastuey, A; Moreno, N; Izquierdo, M; Font, O; Moreno, T; Diez, S; Vázquez, E; Barra, M

    2008-06-15

    The synthesis of geopolymer matrixes from coal (co-)combustion fly ashes as the sole source of silica and alumina has been studied in order to assess both their capacity to immobilise the potentially toxic elements contained in these coal (co-)combustion by-products and their suitability to be used as cement replacements. The geopolymerisation process has been performed using (5, 8 and 12 M) NaOH solutions as activation media and different curing time (6-48 h) and temperature (40-80 degrees C) conditions. Synthesised geopolymers have been characterised with regard to their leaching behaviour, following the DIN 38414-S4 [DIN 38414-S4, Determination of leachability by water (S4), group S: sludge and sediments. German standard methods for the examination of water, waste water and sludge. Institut für Normung, Berlin, 1984] and NEN 7375 [NEN 7375, Leaching characteristics of moulded or monolithic building and waste materials. Determination of leaching of inorganic components with the diffusion test. Netherlands Normalisation Institute, Delft, 2004] procedures, and to their structural stability by means of compressive strength measurements. In addition, geopolymer mineralogy, morphology and structure have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. It was found that synthesised geopolymer matrixes were only effective in the chemical immobilisation of a number of elements of environmental concern contained in fly ashes, reducing (especially for Ba), or maintaining their leachable contents after the geopolymerisation process, but not for those elements present as oxyanions. Physical entrapment does not seem either to contribute in an important way, in general, to the immobilisation of oxyanions. The structural stability of synthesised geopolymers was mainly dependent on the glass content of fly ashes, attaining at the optimal activation conditions (12 M NaOH, 48 h, 80

  14. Emission, distribution and toxicity of polycyclic aromatic hydrocarbons (PAHs) during municipal solid waste (MSW) and coal co-combustion.

    Science.gov (United States)

    Peng, Nana; Li, Yi; Liu, Zhengang; Liu, Tingting; Gai, Chao

    2016-09-15

    Emission and distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) were investigated during municipal solid waste (MSW) and coal combustion alone and MSW/coal blend (MSW weight fraction of 25%) co-combustion within a temperature range of 500°C-900°C. The results showed that for all combustion experiments, flue gas occupied the highest proportion of total PAHs and fly ash contained more high-ring PAHs. Moreover, the 3- and 4-ring PAHs accounted for the majority of total PAHs and Ant or Phe had the highest concentrations. Compared to coal, MSW combustion generated high levels of total PAHs with the range of 111.28μg/g-10,047.22μg/g and had high toxicity equivalent value (TEQ). MSW/coal co-combustion generated the smallest amounts of total PAHs and had the lowest TEQ than MSW and coal combustion alone. Significant synergistic interactions occurred between MSW and coal during co-combustion and the interactions suppressed the formation of PAHs, especially hazardous high-ring PAHs and decreased the TEQ. The present study indicated that the reduction of the yield and toxicity of PAHs can be achieved by co-combustion of MSW and coal.

  15. Co-combustion of olive cake with lignite coal in a circulating fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-05-01

    In this study, olive cake (OC) was co-fired with coal in a circulating fluidized bed of 125 mm diameter and 1800 mm height. Olive cake is a waste from olive oil production. A lignite coal that is most widely used in Turkey (Tuncbilek lignite) was used together with OC and the combustion characteristics of olive cake (OC)+coal mixture were investigated. The combustion experiments were carried out with various excess air ratios. The excess air ratio, {lambda} has been changed between 1.1 and 2.16. Temperature distribution along the bed was measured with thermocouples. On-line concentrations of O{sub 2}, SO{sub 2}, CO{sub 2}, CO, NOx and total hydrocarbons were measured in the flue gas. Various runs were conducted with each mixture of OC and lignite, namely 25, 50 and 75 wt% OC mixed with lignite. These mixtures were burned with various excess air ratios. Combustion efficiencies of olive cake and lignite coal mixtures are calculated, and the optimum conditions for operating parameters are discussed. There is a sharp decrease observed in the combustion losses due to hydrocarbons and CO as the excess air ratio increases. The minimum emissions are observed at about {lambda} = 1.5. The combustion efficiency for lignite coal changes between 82 and 98% for various excess air ratios used in the study. The results suggest that OC is good fuel that can be mixed with lignite coal for cleaner energy production in small-scale industries by using CFB. Less than 50 wt% OC concentration in the fuel mixture is suggested in order to be within the EU limits for emissions. 11 refs., 12 figs., 7 tabs.

  16. Investigation of the combustion characteristics of Zonguldak bituminous coal using DTA and DTG

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S.; Kucukbayrak, S.; Okutan, H. [Istanbul Technical University, Istanbul (Turkey). Dept. of Chemical Engineering

    2006-06-21

    Combustion characteristics of coking, semicoking, and noncoking Turkish bituminous coal samples from Zonguldak basin were investigated applying differential thermal analysis (DTA) and differential thermogravimetry (DTG) techniques. Results were compared with that of the coke from Zonguldak bituminous coal, a Turkish lignite sample from Soma, and a Siberian bituminous coal sample. The thermal data from both techniques showed some differences depending on the proximate analyses of the samples. Noncombustible components of the volatile matter led to important changes in thermal behavior. The data front both methods were, evaluated jointly, and some thermal properties were interpreted considering these methods in a complementary combination.

  17. Coal-fired open cycle MHD combustion plasmas - Chemical equilibrium and transport properties workshop results

    Science.gov (United States)

    Sullivan, L. D.; Klepeis, J. E.; Coderre, W. J.; Fischer, W. H.

    1980-01-01

    For electrical power generation utilizing a high temperature alkali-seeded coal combustion plasma, the certainty of high electrical conductivity in the presence of coal ash and trace impurities is vitally important, especially for use in extrapolation of existing designs to higher power levels, as envisioned for commercial applications. The paper surveys the results of the workshop which provides an industry wide overview of the computational methods and analyses that are currently in use. Attention is given to uncertainty bands for plasma electrical conductivity. Also discussed are other issues such as coal, slag, seed, and conductivity. Finally, the paper gives suggested areas for further work.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  19. Coal Combustion Science quarterly progress report, January--March 1993. Task 1, Coal char combustion: Task 2,, Fate of mineral matter

    Energy Technology Data Exchange (ETDEWEB)

    Hardesty, D.R. [ed.; Hurt, R.H.; Baxter, L.L.

    1994-02-01

    The objective of this work is to obtain insights into the mechanisms of combustion, fragmentation, and final burnout, and to use the insights to aid in the interpretation of the quantitative data generated in Subtasks 1 and 2. The initial image sequences for Illinois No. 6 coal confirm the presence of an early near-extinction process (discussed in previous reports) and the asymptotic nature of the carbon burnout process. The technique also provided important new insights into the processes of particle fragmentation and reagglomeration at high burnout. During this quarter, chemical fractionation tests on coals pulverized to different sizes were completed. These data will help us to asses the accuracy of the fuels characterizations for the purpose of interpreting inorganic release during coal devolatilization. Chemical fractionation tests on mineral species are proceeding for the same purposes, but these are not yet completed.

  20. 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.

  1. Emission factors of polycyclic aromatic hydrocarbons from domestic coal combustion in China.

    Science.gov (United States)

    Geng, Chunmei; Chen, Jianhua; Yang, Xiaoyang; Ren, Lihong; Yin, Baohui; Liu, Xiaoyu; Bai, Zhipeng

    2014-01-01

    Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons (PAHs) are important in flue gas of the stove. By using dilution tunnel system, samples of both gaseous and particulate phases from domestic coal combustion were collected and 18 PAH species were analyzed by GC-MS. The average emission factors of total 18 PAH species was 171.73 mg/kg, ranging from 140.75 to 229.11 mg/kg for bituminous coals, while was 93.98 mg/kg, ranging from 58.48 to 129.47 mg/kg for anthracite coals. PAHs in gaseous phases occupied 95% of the total of PAHs emission of coal combustion. In particulate phase, 3-ring and 4-ring PAHs were the main components, accounting for 80% of the total particulate PAHs. The total toxicity potency evaluated by benzo[a]pyrene-equivalent carcinogenic power, sum of 7 carcinogenic PAH components and 2,3,7,8-tetrachlorodibenzodioxin had a similar tendency. And as a result, the toxic potential of bituminous coal was higher than that of anthracite coal. Efficient emission control should be conducted to reduce PAH emissions in order to protect ecosystem and human health.

  2. Application of rubber anti-aging agents in preventing coal spontaneous combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.; Zhang, R.; Yang, Y.; Yang, H.; Fan, X.

    1999-07-01

    Based on the mechanism of rubber aging and action of anti-aging agents in preventing rubber aging, the free radical chain reaction mechanism of the oxidation of coal was discussed and compound stopping agents were introduced in the paper. The rubber anti-aging agents of aromatic amine are selected for the stopping agent of preventing coal spontaneous combustion. The stopping action of these anti-aging agents and common inorganic salt stopping agents for long flame coal in Gengcun Colliery, Yima city, Henan province in China is researched. The anti-aging agents for the long flame coal have the prominent efficiency and fine stopping action in later period, and inorganic stopping agents containing magnesium chloride salt for the long flame coal have the prominent efficiency in early period, but the compound stopping agents that are composed of the rubber anti-aging agents and magnesium chloride have longer life.

  3. Life cycle assessment analysis of supercritical coal power units

    Science.gov (United States)

    Ziębik, Andrzej; Hoinka, Krzysztof; Liszka, Marcin

    2010-09-01

    This paper presents the Life Cycle Assessment (LCA) analysis concerning the selected options of supercritical coal power units. The investigation covers a pulverized power unit without a CCS (Carbon Capture and Storage) installation, a pulverized unit with a "post-combustion" installation (MEA type) and a pulverized power unit working in the "oxy-combustion" mode. For each variant the net electric power amounts to 600 MW. The energy component of the LCA analysis has been determined. It describes the depletion of non-renewable natural resources. The energy component is determined by the coefficient of cumulative energy consumption in the life cycle. For the calculation of the ecological component of the LCA analysis the cumulative CO2 emission has been applied. At present it is the basic emission factor for the LCA analysis of power plants. The work also presents the sensitivity analysis of calculated energy and ecological factors.

  4. Nitric oxide reduction over biomass and coal chars under fluidized bed combustion conditions: the role of thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Piero Salatino; Anna Di Somma; Roberto Solimene; Riccardo Chirone [Universita degli Studi di Napoli Federico II, Napoli (Italy). Dipartimento di Ingegneria Chimica

    2008-07-01

    The de-NOx potential of biomass-and waste-derived fuels candidate for cofiring with coal is assessed. The experimental procedure is based on operation of a bench scale fluidized bed reactor where NO-doped nitrogen is contacted with batches of the fuel. A second type of experiment has been purposely designed to assess the extent of thermodeactivation of biogenous fuels, i.e. the loss of reactivity toward the NOx-char reaction as char is annealed for pre-set times at temperatures typical of fluidized bed combustion. A simple phenomenological model is developed to shed light on the basic features of the interaction between heterogeneous char-NOx reaction and thermal annealing of the char. Results are discussed in the light of the potential exploitation of synergistic effects on NOx emission associated with cofiring with coal. 21 refs., 8 figs., 1 tab.

  5. Geochemistry of Permian Coal and Its Combustion Residues in Huainan Coalfield, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    INAA (instrumental neutron activation analysis) was used to determine the contents of trace elements in coal samples from 11 workable Permian coal seams in Huainan coalfield. With XRFS (X-ray fluorescence spectrometry), the geochemical composition of its combustion residues from Tianjiaan Power Plant and Luohe Power Plant was analyzed. In addition, the electron microprobe was employed to study the chemical composition of some fly ashes and bottom ashes. Compared with those of the coals around the world, most trace elements of the Huainan coal are characterized by a normal abundance.Like most coals worldwide, the elements Se, S, As, Sb, Br, U and Cl are enriched in Huainan coal according to Clarks value, while the other elements tend to be diluted. The large fluctuation in the contents of trace elements in this kind of coal demonstrates great differences in coal seams. On the other hand, the contents of these elements are very similar in different bottom and fly ash samples. The elements with low organic affinity tend to concentrate in fly and bottom ash than in coal, especially those elements associated with Fe. However, the elements with strong organic affinity tend to be volatile during the combustion. Moreover, the abundance of the elements in fly ash and bottom ash changes with different densities and with different particle sizes. The bottom and fly ashes consist of glass, lime,mullite, coal residues and ferrite minerals. Some residual chars contain higher contents of volatile elements, such as S, P, Cl and As, indicating that the ash containing more residual chars has a strong adsorption of some hazardous elements, suggesting a possible utilization of power plant ash in the field of water cleaning.

  6. 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.

  7. Oxy-fuel combustion of millimeter-sized coal char: Particle temperatures and NO formation

    DEFF Research Database (Denmark)

    Brix, Jacob; Navascués, Leyre Gómez; Nielsen, Joachim Bachmann;

    2013-01-01

    In this work, differences in particle temperature and NO yield during char oxidation in O2/N2 and O2/CO2 atmospheres, respectively, have been examined. A laboratory scale fixed bed reactor, operated isothermally at 1073 K, was used for combustion of millimeter-sized lignite and bituminous coal ch...

  8. 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.

  9. Studying flame combustion of coal-water slurries in the furnaces of power-generating boilers

    Science.gov (United States)

    Osintsev, K. V.

    2012-06-01

    Matters concerned with organizing combustion of different types of coal-water slurries in coalfired boilers at thermal power stations are considered. Recommendations for improving the economic and environmental indicators and for achieving more reliable operation of furnace devices and boiler as a whole are given.

  10. 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 vario...

  11. Effects of coal combustion and gasification upon lung structure and function. Quarterly progress report

    Energy Technology Data Exchange (ETDEWEB)

    Hinton, Dr., David E.

    1980-12-12

    The effects on lungs of emissions from fluidized-bed combustion and coal gasification on man are being studied by inhalation experiments and intratracheal administration of fly ash to hamsters. The hamsters are sacrificed at 1, 3, 6, 9 and 30 days and the lungs examined by methods which are described. (LTN)

  12. Modeling the temperature in coal char particle during fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Vasilije Manovic; Mirko Komatina; Simeon Oka [University of Belgrade, Belgrade (Serbia)

    2008-05-15

    The temperatures of a coal char particle in hot bubbling fluidized bed (FB) were analyzed by a model of combustion. The unsteady model includes phenomena of heat and mass transfer through a porous char particle, as well as heterogeneous reaction at the interior char surface and homogeneous reaction in the pores. The parametric analysis of the model has shown that above 550{sup o}C combustion occurs under the regime limited by diffusion. The experimental results of temperature measurements by thermocouple in the particle center during FB combustion at temperatures in the range 590-710{sup o}C were compared with the model predictions. Two coals of different rank were used: lignite and brown coal, with particle size in the range 5-10 mm. The comparisons have shown that the model can adequately predict the histories of temperatures in char particles during combustion in FB. In the first order, the model predicts the influence of the particle size, coal rank (via porosity), and oxygen concentration in its surroundings. 53 refs., 6 figs., 2 tabs.

  13. Control of mercury emissions from stationary coal combustion sources in China: Current status and recommendations.

    Science.gov (United States)

    Hu, Yuanan; Cheng, Hefa

    2016-11-01

    Coal burning in power plants and industrial boilers is the largest combustion source of mercury emissions in China. Together, power plants and industrial boilers emit around 250 tonnes of mercury each year, or around half of atmospheric mercury emissions from anthropogenic sources in the country. Power plants in China are generally equipped with multi-pollutant control technologies, which offer the co-benefit of mercury removal, while mercury-specific control technologies have been installed in some facilities. In contrast, most industrial boilers have only basic or no flue gas cleaning. A combination of measures, including energy conservation, coal switching and blending, reducing the mercury contents of coals through washing, combustion controls, and flue gas cleaning, can be used to reduce mercury emissions from these stationary combustion sources. More stringent emission standards for the major air pollutants from coal-fired power plants and industrial boiler, along with standards for the previously unregulated mercury, were implemented recently, which is expected to bring significant reduction in their mercury emissions through the necessary upgrades of multi-pollutant and mercury-specific control technologies. Meanwhile, strong monitoring capacity and strict enforcement are necessary to ensure that the combustion sources operate in compliance with the new emission standards and achieve significant reduction in the emissions of mercury and other air pollutants.

  14. Lung X-ray changes in skeletal fluorosis caused by coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.K. [Hubei Sanitary-Epidemiological Station, Wuhan (China)

    1996-02-01

    Lung X-ray findings are reported in 45 cases with skeletal fluorosis in an area contaminated by coal combustion. The findings include chronic bronchitis, with diffuse interstitial fibrosis and pulmonary emphysema. The degree of pulmonary pathological findings and skeletal fluorosis is correlated with patient age. Among the 45 cases were 5 with cardio-pulmonary disease and 5 with tuberculosis.

  15. Behavior of fluorine in the combustion of Chinese coal in small furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Dan Liu; Yuji Sakai; Mitsuo Yamamoto; Masayoshi Sadakata [Ariake National College of Technology, Fukuoka (Japan). Department of Chemistry Science and Engineering

    2006-08-15

    Research into fluoride emissions from coal-combustion systems is becoming increasingly important as the issue of fluoride pollution in China becomes more serious. In some rural areas in China, indoor fluoride pollution has particularly been caused by the use of high fluorine content coal in stoves. As a result, many residents suffer from dental fluorosis and bone fluorosis. In this study, X-ray diffraction (XRD) analysis was carried out to confirm the mode by which inorganic fluorides exist in such coals. Analytical results showed that inorganic fluorides in Chinese coals exist mainly as muscovite and apatite. The fluorine concentration in gases emitted from a boat in a quartz tube furnace was measured during combustion of volatile matter and char. The times for volatile matter and char combustions were determined through continuous monitoring of SO{sub 2}. Experimental results under different combustion conditions showed that fluoride in the emitted gas increased with an increase in oxygen concentration and temperature, while fluoride in the residue decreased with the increase in oxygen concentration and temperature. 23 refs., 8 figs., 2 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-10-01

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

  17. Reducing Power Penalty Related to PostCombustion CO2 Capture in Coal Power Plants

    Directory of Open Access Journals (Sweden)

    Ramona Mihaela Negoi

    2011-09-01

    Full Text Available Considering the important role of coal in energy security and in the same time the growing need to reduce CO2 emissions, amine-based post-combustion CO2 capture is considered as one of the most proper technologies to be implemented in coal fired power plants as well in natural gas fired plants, refinery gas, cement plants etc.. The main challenge for CO2 post-combustion is reducing the energy demand of the process, especially for solvent regeneration. In this paper, the energy reduction potential when waste heat of flue gases is integrated in the CO2 capture configuration scheme is discussed. The results are compared with a conventional coal power plant configuration when low-steam pressure is extracted from the water-steam cycle of the power plant.

  18. The effect of fuel pyrolysis on the coal particle combustion: An analytical investigation

    Directory of Open Access Journals (Sweden)

    Baghsheikhi Mostafa

    2016-01-01

    Full Text Available The aim of this work is to analytically investigate the symmetrical combustion of an isolated coal particle with the fuel pyrolysis effect. The modelling concept of coal particles is similar to that of the liquid droplet combustion but in the case of coal devolatilization, the particles do not shrink like droplet does due to evaporation of liquid fuel. The rate of devolatilization of volatiles can be calculated using the equation that is similar to Arrhenius equation. This model is based on an assumption of combined quasi-steady and transient behaviour of the process and especially focuses on predicting the variations of temperature profile, radius of pyrolysis and transfer number. It is revealed that the entrance of pyrolysis effect into the governing equations leads to the reduction in the film radius and consequently a reduction in the stand-off ratio and transfer number.

  19. Development and testing of commercial-scale, coal-fired combustion systems, Phase 3

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The US Department of Energy's Pittsburgh Energy Technology Center (PETC) is actively pursuing the development and testing of coal-fired combustion systems for residential, commercial, and industrial market sectors. In response, MTCI initiated the development of a new combustor technology based on the principle of pulse combustion under the sponsorship of PETC (Contract No. AC22-83PC60419). The initial pulse combustor development program was conducted in three phases (MTCI, Development of a Pulsed Coal Combustor Fired with CWM, Phase III Final Report, DOE Contract No. AC22-83PC60419, November 1986). Phase I included a review of the prior art in the area of pulse combustion and the development of pulse combustor design concepts. It led to the conclusion that pulse combustors offer technical and base-of-operation advantages over conventional burners and also indicated favorable economics for replacement of oil- and gas-fired equipment.

  20. Non-linear models: coal combustion efficiency and emissions control

    Energy Technology Data Exchange (ETDEWEB)

    Bulsari, A.; Wemberg, A.; Anttila, A.; Multas, A. [Nonlinear Solutions Oy, Turku (Finland)

    2009-04-15

    Today's power plants feel the pressure to limit their NOx emissions and improve their production economics. The article describes how nonlinear models are effective for process guidance of various kinds of processes, including coal fired boilers. These models were developed for the Naantati 2 boiler at the electricity and heat generating coal-fired plant in Naantali, near Turku, Finland. 4 refs., 6 figs.

  1. National Coal Utilization Assessment: a preliminary assessment of coal utilizaton in the South. [Southern USA to 2020; forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Berry, L. B.; Bjornstad, D. J.; Boercker, F. D.

    1978-01-01

    Some of the major problems and issues related to coal development and use in the South are identified and assessed assuming a base-case energy scenario for the next 45 years. This scenario assumes a midrange of coal use and a relatively high rate of nuclear use over the forecast period. The potential impacts from coal development and use are significant, particularly in the 1990-2020 time period. Practically all available sites suitable for power plant development in the assessment will be utilized by 2020. Overall, sulfur dioxide will be well below the annual primary standard; however, several local hot-spot areas were identified. In addition, sulfate concentrations will be increased significantly, particularly over Virginia, West Virginia, and northern Kentucky. Coal mining is expected to affect 6 of the 12 major ecological regions. Coal mining will lead to increased average suspended sediment concentrations in some river basins, and special measures will be required to control acid discharges from active mines in pyritic regions. The increased mining of coal and subsequent sulfur dioxide increases from its combustion may also give rise to a land-use confrontation with food and fiber production. Potential health effects from exposure to sulfur dioxide and sulfates are expected to increase rapidly in several areas, particularly in parts of Kentucky, Maryland, District of Columbia, and Georgia. Regional social costs should be relatively low, although some site-specific costs are expected to be very high. Alternative energy technologies, careful siting selection, and deployment of environmental control technologies and operating policies will be required to reduce or mitigate these potential impacts.

  2. 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.

  3. 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

    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...

  4. 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.

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

    OpenAIRE

    Dhungel, Bhupesh

    2010-01-01

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

  6. Arsenic in coal of the Thar coalfield, Pakistan, and its behavior during combustion.

    Science.gov (United States)

    Ali, Jamshed; Kazi, Tasneem G; Baig, Jameel A; Afridi, Hassan I; Arain, Mariam S; Brahman, Kapil D; Naeemullah; Panhwar, Abdul H

    2015-06-01

    The aim of the current study is to evaluate the occurrence of arsenic in coal collected from Thar coalfield, Pakistan, and its behavior during the combustion. Fractionation of arsenic (As) in coal samples was carried out by Community Bureau of Reference sequential extraction scheme (BCR-SES) and single-step-based BCR method (BCR-SS). These methods are validated using the certified reference material of sediment BCR 701 and standard addition method. The stepwise fractions of As in laboratory-made ash (LMA) have been also investigated. The extractable As content associated with different phases in coal and LMA samples were analyzed by electrothermal atomic absorption spectrophotometer. The extraction efficiency of As by BCR-SS was slightly higher than BCR-SES, while the difference was not significant (p combustion of the coal, >85 % of As may be released into atmosphere. The relative mobility of As in the coal samples was found in increasing order as follows: oxidizable fraction coal samples of block III as compared to block V (p > 0.05).

  7. 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.

  8. Combustion of olive cake and coal in a bubbling fluidized bed with secondary air injection

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-15

    Combustion performances and emission characteristics of olive cake and coal are investigated in a bubbling fluidized bed. Flue gas concentrations of O{sub 2}, CO, SO{sub 2}, NOx, and total hydrocarbons (C{sub m}H{sub n}) were measured during combustion experiments. Operational parameters (excess air ratio {lambda}, secondary air injection) were changed and variation of pollutant concentrations and combustion efficiency with these operational parameters were studied. The temperature profiles measured along the combustor column was found higher in the freeboard for olive cake than coal due to combustion of hydrocarbons mostly in the freeboard. Combustion efficiencies in the range of 83.6-90.1% were obtained for olive cake with {lambda} of 1.12-2.30. For the setup used in this study, the optimum operating conditions with respect to NOx and SO{sub 2} emissions were found as 1.2 for {lambda}, and 50 L/min for secondary air flowrate for the combustion of olive cake. 10 refs., 8 figs., 3 tabs.

  9. 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.

  10. 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.

  11. Assessment of Literature Related to Combustion Appliance Venting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, V. H.; Less, B. D.; Singer, B. C.; Stratton, J. C.; Wray, C. P.

    2015-02-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents their technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.

  12. Application of fault tree approach for the causation mechanism of urban haze in Beijing--Considering the risk events related with exhausts of coal combustion.

    Science.gov (United States)

    Huang, Weiqing; Fan, Hongbo; Qiu, Yongfu; Cheng, Zhiyu; Qian, Yu

    2016-02-15

    Haze weather has become a serious environmental pollution problem which occurs in many Chinese cities. One of the most critical factors for the formation of haze weather is the exhausts of coal combustion, thus it is meaningful to figure out the causation mechanism between urban haze and the exhausts of coal combustion. Based on above considerations, the fault tree analysis (FAT) approach was employed for the causation mechanism of urban haze in Beijing by considering the risk events related with the exhausts of coal combustion for the first time. Using this approach, firstly the fault tree of the urban haze causation system connecting with coal combustion exhausts was established; consequently the risk events were discussed and identified; then, the minimal cut sets were successfully determined using Boolean algebra; finally, the structure, probability and critical importance degree analysis of the risk events were completed for the qualitative and quantitative assessment. The study results proved that the FTA was an effective and simple tool for the causation mechanism analysis and risk management of urban haze in China.

  13. 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)

  14. 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

  15. Flame radiant image numeralization for pulverized coal combustion in BF raceway

    Institute of Scientific and Technical Information of China (English)

    WEN Liang-ying; OU Yang-qi; BAI Chen-guang; WANG Hua

    2005-01-01

    In order to establish correlativity between pulverized coal combustion in a blast furnace raceway and its radiant image, we investigated the relationships between two dimensional radiant images and three dimensional radiant energy in a blast furnace raceway, focusing on the correlativity of the numerical simulation of combustion processes with the connection of radiant images information and space temperature distribution. We calculated the uneven radiate characteristic parameterby taking radiant images as a kind of radiative boundary for numerical simulation of combustion processes, and put forward a method to examine three-dimensional temperatures distribution in blast furnace raceway by radiant image processing. The numeral temperature fields matching the real combustion can be got by the numeric image processing technique.

  16. Comprehensive Mathematical Model for Coal Combustion in a Circulating Fluidized Bed Combustor

    Institute of Scientific and Technical Information of China (English)

    金晓钟; 吕俊复; 杨海瑞; 刘青; 岳光溪; 冯俊凯

    2001-01-01

    Char combustion is on a special reducing condition in the dense bed of a circulating fluidized bedcombustor. Experimental findings were used to develop a comprehensive mathematical model to simulate thehydrodynamic and combustion processes in a circulating fluidized bed combustor. In the model, gas-solidinteraction was used to account for the mass transfer between the bubble phase and the emulsion phase in thedense bed, which contributes to the reducing atmosphere in the dense bed. A core-annular structure wasassumed in the dilute area rather than a one-dimensional model. The submodels were combined to build thecomprehensive model to analyze the combustion in a circulating fluidized bed combustor and the effect ofoperating parameters on the coal combustion. The model predictions agree well with experimental results.

  17. 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.

  18. 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.

  19. The spontaneous combustion of coal and its by-products in the Witbank and Sasolburg coalfields of South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Pone, J. Denis N. [Energy and Geo-Environmental Engineering, The Pennsylvania State University, 228 Housler Building, University Park, PA 16802 (United States); Hein, Kim A.A. [School of Geosciences, University of the Witwatersrand Johannesburg, P/Bag 3, 2050, WITS (South Africa); Stracher, Glenn B. [Division of Science and Mathematics, East Georgia College, Swainsboro, Georgia 30401 (United States); Annegarn, Harold J. [Department of Geography and Environmental Management, University of Johannesburg, P.O. Box 524, Auckland Park, 2006 (South Africa); Finkleman, Robert B. [University of Texas at Dallas, Department of Geosciences, Richardson, TX 75083-0688 (United States); Blake, Donald R. [Department of Chemistry, 570 Rowland Hall, University of California, Irvine, CA 92697-2025 (United States); McCormack, John K. [Electron Microbeam Facility, Department of Geological Sciences, MS 172, Mackay School of Mines, University of Nevada, Reno, Navada 8955-0047 (United States); Schroeder, Paul [Department of Geology, University of Georgia, 210 Field Street, Athens, GA 30602-2501 (United States)

    2007-10-01

    nature of the risks to human health and the environment of most of the compounds in gas and CFGM by-products of spontaneous combustion at the Witbank and Sasolburg coalfields are unknown and merit investigation. Fires caused by spontaneously combusted coal are pervasive in the coalfields and the health consequences of exposure to hazardous elements are a serious risk. It would be prudent to undertake an environmental impact assessment of these elements in order to determine the extent of their impact on mine workers and the environment in the Witbank and Sasolburg coalfields. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

  1. 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.)

  2. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

  4. The US Geological Survey's national coal resource assessment: The results

    Science.gov (United States)

    Ruppert, L.F.; Kirschbaum, M.A.; Warwick, P.D.; Flores, R.M.; Affolter, R.H.; Hatch, J.R.

    2002-01-01

    The US Geological Survey and the State geological surveys of many coal-bearing States recently completed a new assessment of the top producing coal beds and coal zones in five major producing coal regions the Appalachian Basin, Gulf Coast, Illinois Basin, Colorado Plateau, and Northern Rocky Mountains and Great Plains. The assessments, which focused on both coal quality and quantity, utilized geographic information system technology and large databases. Over 1,600,000 million short tons of coal remain in over 60 coal beds and coal zones that were assessed. Given current economic, environmental, and technological restrictions, the majority of US coal production will occur in that portion of the assessed coal resource that is lowest in sulfur content. These resources are concentrated in parts of the central Appalachian Basin, Colorado Plateau, and the Northern Rocky Mountains. ?? Elsevier Science B.V. All rights reserved.

  5. 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.

  6. Optical and chemical characterization of aerosols emitted from coal, heavy and light fuel oil, and small-scale wood combustion.

    Science.gov (United States)

    Frey, Anna K; Saarnio, Karri; Lamberg, Heikki; Mylläri, Fanni; Karjalainen, Panu; Teinilä, Kimmo; Carbone, Samara; Tissari, Jarkko; Niemelä, Ville; Häyrinen, Anna; Rautiainen, Jani; Kytömäki, Jorma; Artaxo, Paulo; Virkkula, Aki; Pirjola, Liisa; Rönkkö, Topi; Keskinen, Jorma; Jokiniemi, Jorma; Hillamo, Risto

    2014-01-01

    Particle emissions affect radiative forcing in the atmosphere. Therefore, it is essential to know the physical and chemical characteristics of them. This work studied the chemical, physical, and optical characteristics of particle emissions from small-scale wood combustion, coal combustion of a heating and power plant, as well as heavy and light fuel oil combustion at a district heating station. Fine particle (PM1) emissions were the highest in wood combustion with a high fraction of absorbing material. The emissions were lowest from coal combustion mostly because of efficient cleaning techniques used at the power plant. The chemical composition of aerosols from coal and oil combustion included mostly ions and trace elements with a rather low fraction of absorbing material. The single scattering albedo and aerosol forcing efficiency showed that primary particles emitted from wood combustion and some cases of oil combustion would have a clear climate warming effect even over dark earth surfaces. Instead, coal combustion particle emissions had a cooling effect. Secondary processes in the atmosphere will further change the radiative properties of these emissions but are not considered in this study.

  7. 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.

  8. Study on emission and retention of fluorine during coal combustion in the chain-grate furnace

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.; Wu, X.; Yao, Q.; Cao, X.; Zhao, X.; Cen, K.

    1998-07-01

    The experimental results of emission and retention of fluorine during coal combustion in a pilot-scale test facility--0.5 tons steam/per hour chain-grate furnace are reported in this paper. The test coal is mixed coal of Yanzhou coal and Changguan coal. The fluorine content in the coal is 150 ppm. The fuel-bed temperature is 1,000--1,250 C. The results show about 80% fluorine in coal releases into the atmosphere. The gaseous state fluorine exists mainly as HF and SiF{sub 4}. In addition, the ratio of gas-fluorine and dust-fluorine in flue gas is obtained. The retention of fluorine by Calcium-based sorbent is the main work in this paper. An efficient sorbent for retention of fluorine is developed. The sorbent is mainly composed of industrial waste material with Calcium, such as carbide slag, white mud, steel residue, lime kiln residue and so on. The experimental results show that the retention of fluorine is related to the kind of sorbent, amount of sorbent, firing temperature. The efficiency of fluorine retention is about 70--80% for adding the sorbent of 7--12% by wt.

  9. Study on emission and retention of fluorine during coal combustion in the chain-grate furnace

    Energy Technology Data Exchange (ETDEWEB)

    Jianzhong Liu; Xiaorong Wu; Qiang Yao [Zhejiang Univ., Hangzhou (China)] [and others

    1998-04-01

    The experimental results of emission and retention of fluorine during coal combustion in a pilot-scale test facility--0.5 tons steam/per hour chain-grate furnace are reported in this paper. The test coal is mixed coal of Yanzhou coal and Changguan coal. The fluorine content in the coal is 150ppm. The fuel-bed temperature is 1000-1250{degrees}C. The results show about 80% fluorine in coal releases into the atmosphere. The gaseous state fluorine exists mainly as HF and SiF{sub 4}. In addition, the ratio of gas-fluorine and dust-fluorine in flue gas is obtained. The retention of fluorine by Calcium-based sorbent is main work in this paper. A efficient sorbent for retention of fluorine is developed. The sorbent is mainly composed of industrial waste material with Calcium, such as carbide slag, white mud, steel residue, limekiln residue and so on. The experimental results show that the retention of fluorine is related to the kind of sorbent, amount of sorbent, firing temperature. The efficiency of fluorine retention is about 70%-80% for adding the sorbent of 7-12% by wt.

  10. Combustion and leaching behavior of elements in the argonne premium coal samples

    Science.gov (United States)

    Finkelman, R.B.; Palmer, C.A.; Krasnow, M.R.; Aruscavage, P. J.; Sellers, G.A.; Dulong, F.T.

    1990-01-01

    Eight Argonne Premium Coal samples and two other coal samples were used to observe the effects of combustion and leaching on 30 elements. The results were used to infer the modes of occurrence of these elements. Instrumental neutron activation analysis indicates that the effects of combustion and leaching on many elements varied markedly among the samples. As much as 90% of the selenium and bromine is volatilized from the bituminous coal samples, but substantially less is volatilized from the low-rank coals. We interpret the combustion and leaching behavior of these elements to indicate that they are associated with the organic fraction. Sodium, although nonvolatile, is ion-exchangeable in most samples, particularly in the low-rank coal samples where it is likely to be associated with the organic constituents. Potassium is primarily in an ion-exchangeable form in the Wypdak coal but is in HF-soluble phases (probably silicates) in most other samples. Cesium is in an unidentified HNO3-soluble phase in most samples. Virtually all the strontium and barium in the low-rank coal samples is removed by NH4OAc followed by HCl, indicating that these elements probably occur in both organic and inorganic phases. Most tungsten and tantalum are in insoluble phases, perhaps as oxides or in organic association. Hafnium is generally insoluble, but as much as 65% is HF soluble, perhaps due to the presence of very fine grained or metamict zircon. We interpret the leaching behavior of uranium to indicate its occurrence in chelates and its association with silicates and with zircon. Most of the rare-earth elements (REE) and thorium appear to be associated with phosphates. Differences in textural relationships may account for some of the differences in leaching behavior of the REE among samples. Zinc occurs predominantly in sphalerite. Either the remaining elements occur in several different modes of occurrence (scandium, iron), or the leaching data are equivocal (arsenic, antimony

  11. Use of anti-pyrogenic powder to prevent spontaneous combustion of coal

    Energy Technology Data Exchange (ETDEWEB)

    Maevskaya, V.M.; Baskakov, V.I.; Boldin, V.A.

    1986-07-01

    The paper describes the generation of endogenic fires during extraction, by the shield method, of thick seams of coal prone to spontaneous combustion, outlines the disadvantages of current system of extinguishing and preventing such fires and proposes the use of anti-pyrogenic powder for this purpose. The powder, which is composed of carbanide and diammonia phosphate and is non-toxic, inexpensive and readily available, is pumped via boreholes under pressure into the coal pillar between horizons prior to its being caved in order to prevent generation of endogenic fires in the caved area of the extraction pillar by starving the fire zone of oxygen. Successful applications of this method are described.

  12. Transformations of inorganic coal constituents in combustion systems. Volume 2, Sections 6 and 7: 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

    Results from an experimental investigation of the mechanisms governing the ash aerosol size segregated composition resulting from the combustion of pulverized coal in a laboratory scale down-flow combustor are described. The results of modeling activities used to interpret the results of the experiments conducted under his subtask are also described in this section. Although results from the entire program are included, Phase II studies which emphasized: (1) alkali behavior, including a study of the interrelationship between potassium vaporization and sodium vaporization; and (2) iron behavior, including an examination of the extent of iron-aluminosilicate interactions, are highlighted. Idealized combustion determination of ash particle formation and surface stickiness are also described.

  13. Structure-Based Predictive Model for Coal Char Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Christopher Hadad; Joseph Calo; Robert Essenhigh; Robert Hurt

    1998-04-08

    Progress was made this period on a number of separate experimental and modelling activities. At Brown, the models of carbon nanostructure evolution were expanded to consider high-rank materials with initial anisotropy. The report presents detailed results of Monte Carlo simulations with non-zero initial layer length and with statistically oriented initial states. The expanded simulations are now capable of describing the development of nanostructure during carbonization of most coals. Work next quarter will address the remaining challenge of isotropic coke-forming coals. Experiments at Brown yielded important data on the "memory loss" phenomenon in carbon annealing, and on the effect of mineral matter on high-temperature reactivity. The experimental aspects of the Brown work will be discussed in detail in the next report.

  14. PAH emissions from coal combustion and waste incineration.

    Science.gov (United States)

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

    2016-11-15

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

  15. UTILIZATION OF LOW NOx COAL COMBUSTION BY-PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-01

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

  16. Effect of freeboard extension on co-combustion of coal and olive cake in a fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Akpulat, O.; Varol, M.; Atimtay, A.T. [Middle East Technical University, Ankara (Turkey). Dept. of Environmental Engineering

    2010-08-15

    In this study, flue gas emissions and combustion efficiencies during combustion and co-combustion of olive cake and coal were investigated in a bubbling fluidized bed. Temperature distributions along the combustion column and flue gas concentrations of O{sub 2}, CO, SO{sub 2} and NOx were measured during combustion experiments. Two sets of experiments were performed to examine the effect of fuel composition, excess air ratio and freeboard extension on flue gas emissions and combustion efficiency. The results of the experiments showed that coal combustion occurs at lower parts of the combustion column whereas olive cake combustion takes place more in the freeboard region. As olive cake percentage in the fuel mixture increased, CO emissions increased, SO{sub 2} and NOx emissions decreased. Additionally, flue gas emissions could be lowered with the freeboard extension while burning biomass or biomass/coal mixtures. Noticeable decrease in CO emissions and slight increase in combustion efficiencies were observed with a column height of 1900 mm instead of 900 mm.

  17. Effect of freeboard extension on co-combustion of coal and olive cake in a fluidized bed combustor.

    Science.gov (United States)

    Akpulat, Onur; Varol, Murat; Atimtay, Aysel T

    2010-08-01

    In this study, flue gas emissions and combustion efficiencies during combustion and co-combustion of olive cake and coal were investigated in a bubbling fluidized bed. Temperature distributions along the combustion column and flue gas concentrations of O(2), CO, SO(2) and NO(x) were measured during combustion experiments. Two sets of experiments were performed to examine the effect of fuel composition, excess air ratio and freeboard extension on flue gas emissions and combustion efficiency. The results of the experiments showed that coal combustion occurs at lower parts of the combustion column whereas olive cake combustion takes place more in the freeboard region. As olive cake percentage in the fuel mixture increased, CO emissions increased, SO(2) and NO(x) emissions decreased. Additionally, flue gas emissions could be lowered with the freeboard extension while burning biomass or biomass/coal mixtures. Noticeable decrease in CO emissions and slight increase in combustion efficiencies were observed with a column height of 1900 mm instead of 900 mm.

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

    Directory of Open Access Journals (Sweden)

    Vidian Fajri

    2017-01-01

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

  19. Low—NOx Combustion and Experimental Investigation in a ROtary Type Pulverized Coal Classifier

    Institute of Scientific and Technical Information of China (English)

    WenjunKong; ShangmoCheng; 等

    1995-01-01

    In order to improve the combustion conditions,maximize the carbon burnout for low-NOx firing systems and meet the requirements for ignition and flame stabilization as low volatile and low quality coal are burned in boilers,finer pulverzed coal should be used .Hence.it is of great practical importance to study the rotary type classifier for the MPS type medium-speed mill.In this pper,we first review the low-NOx combustion technology,then some model tests of rotating classifier are completed.The results show that the classifier performances are very satisfactory,with the fineness of the finished produce being R90f<10%,Rules for designing and controlling rotating classifier are also developed in this paper.

  20. Experimental Study on the Changing Rules of Coal Fire Indictor Gases of the Whole Combustion Phases in Confined Space

    Directory of Open Access Journals (Sweden)

    Baiwei Lei

    Full Text Available ABSTRACT When the coal mine fire occurs, it is crucial to judge the fire combustion state by analyzing indicator gases concentration and changing trends of various gas ratios in order to formulate proper rescue measures. It's an effective methodology to estimate the changes of combustion state in coal mine fire accurately by the trends analysis of indicator gases and gas ratios independent of the external environment disturbs, such as air leakage and inner gases injection. However, there are few experimental researches about the changing rules of indicator gases and gas ratios at different combustion phases at present. Therefore, this paper has established a small-sized coal combustion experimental platform in confined space, on which the experimental studies on variation trends about indicator gases and gas ratios of the whole combustion phases are conducted. The experiment results have shown that the coal combustion trends could be accurately estimated by analyzing the relationship between indicator gases and gas ratios among different combustion phases. In the end of this paper, the conclusions are verified by a real coal mine fire disaster relief case, and the practical results are in agreement with the experimental analysis.

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

    Science.gov (United States)

    Nodelman; Pisupati; Miller; Scaroni

    2000-05-29

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

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

    OpenAIRE

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

    2011-01-01

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

  3. Fluidized-bed reactor model with generalized particle balances. Part 2. Coal combustion application

    Energy Technology Data Exchange (ETDEWEB)

    Overturf, B.W.; Reklaitis, G.V.

    1983-09-01

    In the second part, the model is applied to the study of an atmospheric fluidized-bed coal combustor. Case studies are investigated to show the effects of a number of parameters. Proper representation of the grid region and use of actual feed distributions are shown to be essential to the prediction of combustor performance. Better particle elutriation and single-particle combustion sub-models are found to be key requirements for improved combustor modelling.

  4. Systems of ignition and combustion stabilization for water-coal fuel

    Directory of Open Access Journals (Sweden)

    Zasypkin Ivan M.

    2012-01-01

    Full Text Available The paper presents the review of researches of the ignition and combustion stabilization of the water-coal fuel. Working models of plants are described, the results of their tests in laboratory and industrial conditions are given. Two schemes of the WCF ignition are presented - one with burners with hydrocarbon (solar fuel, and the other with the system of plasma ignition. Advantages of these two systems are described. The promising future of the SPI application in industrial conditions is demonstrated.

  5. Alkali-Alumina Sorbents for Regenerable SO_2 Removal in Fluidized-Coal Combustion

    OpenAIRE

    Gavalas, George R.; Weston, Theresa A.; Stephanopoulos, Maria F.

    1985-01-01

    Sodium and sodium-lithium oxides supported on porous alumina have been investigated as regenerable SO_2 sorbents for fluidized coal combustion. In adsorption the oxides are converted to sulfates. In regeneration, carried out by reduction with CO, the sulfates are converted back to oxides while sulfur is removed in elemental form (S_2), SO_2 and COS. The transient composition of sorbent and gaseous products was measured in a thermogravimetric analyzer and a packed-bed microreactor in order to ...

  6. Signal Processing Methods for Liquid Rocket Engine Combustion Spontaneous Stability and Rough Combustion Assessments

    Science.gov (United States)

    Kenny, R. Jeremy; Casiano, Matthew; Fischbach, Sean; Hulka, James R.

    2012-01-01

    Liquid rocket engine combustion stability assessments are traditionally broken into three categories: dynamic stability, spontaneous stability, and rough combustion. This work focuses on comparing the spontaneous stability and rough combustion assessments for several liquid engine programs. The techniques used are those developed at Marshall Space Flight Center (MSFC) for the J-2X Workhorse Gas Generator program. Stability assessment data from the Integrated Powerhead Demonstrator (IPD), FASTRAC, and Common Extensible Cryogenic Engine (CECE) programs are compared against previously processed J-2X Gas Generator data. Prior metrics for spontaneous stability assessments are updated based on the compilation of all data sets.

  7. LUNG TUMOR KRAS AND TP53 MUTATIONS IN NONSMOKERS REFLECT EXPOSURE TO PAH-RICH COAL COMBUSTION EMISSIONS

    Science.gov (United States)

    Lung Tumor KRAS and TP53 Mutations in Nonsmokers Reflect Exposure to PAH-Rich Coal Combustion Emissions Use of smoky coal in unvented homes in Xuan Wei County, Yunnan Province, China, is associated with lung cancer among nonsmoking females. Such women have the highest...

  8. Progression in sulfur isotopic compositions from coal to fly ash: Examples from single-source combustion in Indiana

    Science.gov (United States)

    Yaofa, Jiang; Elswick, E.R.; Mastalerz, Maria

    2008-01-01

    Sulfur occurs in multiple mineral forms in coals, and its fate in coal combustion is still not well understood. The sulfur isotopic composition of coal from two coal mines in Indiana and fly ash from two power plants that use these coals were studied using geological and geochemical methods. The two coal beds are Middle Pennsylvanian in age; one seam is the low-sulfur ( 5%) Springfield Coal Member of the Petersburg Formation. Both seams have ash contents of approximately 11%. Fly-ash samples were collected at various points in the ash-collection system in the two plants. The results show notable difference in ??34S for sulfur species within and between the low-sulfur and high-sulfur coal. The ??34S values for all sulfur species are exclusively positive in the low-sulfur Danville coal, whereas the ??34S values for sulfate, pyritic, and organic sulfur are both positive and negative in the high-sulfur Springfield coal. Each coal exhibits a distinct pattern of stratigraphic variation in sulfur isotopic composition. Overall, the ??34S for sulfur species values increase up the section in the low-sulfur Danville coal, whereas they show a decrease up the vertical section in the high-sulfur Springfield coal. Based on the evolution of ??34S for sulfur species, it is suggested that there was influence of seawater on peat swamp, with two marine incursions occurring during peat accumulation of the high-sulfur Springfield coal. Therefore, bacterial sulfate reduction played a key role in converting sulfate into hydrogen sulfide, sulfide minerals, and elemental sulfur. The differences in ??34S between sulfate sulfur and pyritic sulfur is very small between individual benches of both coals, implying that some oxidation occurred during deposition or postdeposition. The ??34S values for fly ash from the high-sulfur Springfield coal (averaging 9.7???) are greatly enriched in 34S relative to those in the parent coal (averaging 2.2???). This indicates a fractionation of sulfur isotopes

  9. The development of low NOx burners under the IEA Coal Combustion Sciences agreement

    Energy Technology Data Exchange (ETDEWEB)

    Whaley, H. [CANMET Energy Technology Centre, Ottawa, Ontario (Canada)

    1997-09-01

    Canada has been involved in the International Energy Agency (IEA) implementing agreement on coal combustion sciences since 1985. The other countries belonging to this agreement are Australia, Germany, Denmark, Finland, Italy, the Netherlands, Sweden, the United Kingdom and the US. There are two operating annexes, the first, Annex 1 being task-shared, in which designated research projects within the participating countries are reported on an annual basis. Annex 2 is cost-shared and the research is conducted at the International Flame Research Foundation (IFRF) in the Netherlands and paid for by the participants, Canada, Germany, the Netherlands and the UK. The objectives of Annex 2 are to develop advanced low NOx coal burners for power boilers and to characterize their performance with a wide range of coals and coal blends. Two burners have been selected as showing great promise in suppressing NOx formation, thereby reducing emissions to below regulatory levels. One is an aerodynamically air-staged burner (AASB) and the other an internally fuel-staged burner (IFSB). Both can utilize a single boiler entry port, which makes them ideal for retrofitting, the former relies on combustion air staging, the latter on fuel staging or reburning. The IFSB, when developed to a commercial stage, is anticipated to meet projected Canadian NOx regulations for the foreseeable future. Supplementary aspects of the program have been coal characterization, ash behavior and deposition, advanced in-flame measurement technique development and validation data bases for flame, combustion and NOx modeling. This presentation will focus on the two low NOx burners developed under the Annex 2 program.

  10. Performance Analysis of a Coal-Fired External Combustion Compressed Air Energy Storage System

    Directory of Open Access Journals (Sweden)

    Wenyi Liu

    2014-11-01

    Full Text Available Compressed air energy storage (CAES is one of the large-scale energy storage technologies utilized to provide effective power peak load shaving. In this paper, a coal-fired external combustion CAES, which only uses coal as fuel, is proposed. Unlike the traditional CAES, the combustion chamber is substituted with an external combustion heater in which high-pressure air is heated before entering turbines to expand in the proposed system. A thermodynamic analysis of the proposed CAES is conducted on the basis of the process simulation. The overall efficiency and the efficiency of electricity storage are 48.37% and 81.50%, respectively. Furthermore, the exergy analysis is then derived and forecasted, and the exergy efficiency of the proposed system is 47.22%. The results show that the proposed CAES has more performance advantages than Huntorf CAES (the first CAES plant in the world. Techno-economic analysis of the coal-fired CAES shows that the cost of electricity (COE is $106.33/MWh, which is relatively high in the rapidly developing power market. However, CAES will be more likely to be competitive if the power grid is improved and suitable geographical conditions for storage caverns are satisfied. This research provides a new approach for developing CAES in China.

  11. National Coal Utilization Assessment. a preliminary assessment of the health and environmental effects of coal utilization in the Midwest. Volume I. Energy scenarios, technology characterizations, air and water resource impacts, and health effects

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    This report presents an initial evaluation of the major health and environmental issues associated with increased coal use in the six midwestern states of Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin. Using an integrated assessment approach, the evaluation proceeds from a base-line scenario of energy demand and facility siting for 1975-2020. Emphasis is placed on impacts from coal extraction, land reclamation, coal combustion for electrical generation, and coal gasification. The range of potential impacts and constraints is illustrated by a second scenario that represents an expected upper limit for coal utilization in Illinois. The following are among the more significant issues identified and evaluated in this study: If environmental and related issues can be resolved, coal will continue to be a major source of energy for the Midwest; existing sulfur emission constraints will increase use of western coal; the resource requirements and environmental impacts of coal utilization will require major significant environmental and economic tradeoffs in site selection; short-term (24-hr) ambient standards for sulfur dioxide will limit the sizes of coal facilities or require advanced control technologies; an impact on public health may result from long-range transport of airborne sulfur emissions from coal facilities in the Midwest; inadequately controlled effluents from coal gasification may cause violations of water-quality standards; the major ecological effects of coal extraction are from pre-mining and post-reclamation land use; and sulfur dioxide is the major potential contributor to effects on vegetation of atmospheric emissions from coal facilities.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

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

  13. USGS TOXIC SUBSTANCES FROM COAL COMBUSTION -- FORMS OF OCCURRENCE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Allan Kolker; Stanley J. Mroczkowski; Curtis A. Palmer; Robert B. Finkelman

    1999-10-01

    Leaching procedures have been completed for the three Phase 2 coals. Chemical analyses have been returned for the whole coals, allowing leaching results to be determined as data on the leachates and solid residues become available. Problems with the nitric acid leaching step twice necessitated repeating the entire procedure for the Ohio and North Dakota samples. Similarly, leaching of the Wyodak sample was repeated once. Analytical results have been returned for all but the last complete round of leaching, which was conducted after modification of the procedure for the nitric acid step. Re-leaching of solid residues prepared under the old procedure confirms that pyrite recovery using the new method is complete. Development of an improved analytical method for Hg continues, but emphasis has shifted from the atomic fluorescence method to an automated direct analysis method that offers similar or better sensitivity. The cold vapor atomic absorption (CVAA) method has been used in the interim for whole coals. During the reporting period Dr. Kolker traveled to Stanford University to evaluate the Stanford/USGS SHRIMP-RG ion microprobe for project purposes and generate trace-element results for illite/smectite in project coals. Initial SHRIMP results for Cr in these samples confirm the Phase 1 conclusion that its concentration in clays is just below the detection limit ({approximately} 100--200 ppm) for electron microprobe analysis. The SHRIMP-RG offers promise for other project priorities, including determination of Hg in sulfides and of As in fly-ash. Use of the SEM and electron microprobe continued during the last half-year, and has been especially useful in support of the ion probe effort. Among other procedures conducted, low temperature ashing has been completed and XRD determinations are underway. Splits of leached residues have been taken for XAFS analysis. The authors expect the first of these to be determined shortly by their Univ. of Kentucky colleagues. These

  14. Mathematical modeling of the heat treatment and combustion of a coal particle. III. Volatile escape stage

    Science.gov (United States)

    Enkhjargal, Kh.; Salomatov, V. V.

    2011-05-01

    The present paper is a continuation of previous publications of the authors in this journal in which two phases of the multistage process of combustion of a coal particle were considered in detail with the help of mathematical modeling: its radiation-convection heating and drying. In the present work, the escape dynamics of volatiles is investigated. The physico-mathematical model of the thermodestruction of an individual coal particle with a dominant influence of endothermal effects has been formulated. Approximate-analytical solutions of this model that are of paramount importance for detailed analysis of the influence of the physical and regime parameters on the escape dynamics of volatiles have been found. The results obtained form the basis for engineering calculations of the volatile escape stage and can be used successfully in the search for effective regimes of burning of various solid fuels, in particular, Shivé-Ovoos coal of Mongolia.

  15. Carbon-centered free radicals in particulate matter emissions from wood and coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Linwei Tian; Catherine P. Koshland; Junko Yano; Vittal K. Yachandra; Ignatius T.S. Yu; S.C. Lee; Donald Lucas [Chinese University of Hong Kong, Hong Kong (China). School of Public Health

    2009-05-15

    Electron paramagnetic resonance (EPR) spectroscopy was used to measure the free radicals in the particulate matter (PM) emissions from wood and coal combustion. The intensity of radicals in PM dropped linearly within two months of sample storage and stabilized after that. This factor of storage time was adjusted when comparing radical intensities among different PM samples. An inverse relationship between coal rank and free radical intensities in PM emissions was observed, which was in contrast with the pattern of radical intensities in the source coals. The strong correlation between intensities of free radical and elemental carbon in PM emissions suggests that the radical species may be carbon-centered. The increased g-factors, 2.0029-2.0039, over that of purely carbon-centered radicals may indicate the presence of vicinal oxygen heteroatom. The redox and biology activities of these carbon-centered radicals are worthy of evaluation. 22 refs., 4 figs., 1 tab.

  16. Advances in LES of Two-phase Combustion (II) LES of Complex Gas-Particle Flows and Coal Combustion

    Institute of Scientific and Technical Information of China (English)

    周力行; 胡璨元

    2012-01-01

    Large-eddy simulation (LES) is under its rapid development and is recognized as a possible second gen- eration of CFD methods used in engineering. Large-eddy simulation of two-phase flows and combustion is particu- larly important for engineering applications. Some investigators, including the present authors, give their review on LES of spray combustion in gas-turbine combustors and internal combustion engines. However, up to now only a few papers are related to the state-of-the-art on LES of gas-particle flows and combustion. In this paper a review of the advances in LES of complex gas-particle flows and coal combustion is presented. Different sub-grid scale (SGS) stress models and combustion models are described, some of the main results are summarized, and some research needs are discussed.

  17. Modelling of the pulverised coal preparation for combustion in a plasma chamber

    Energy Technology Data Exchange (ETDEWEB)

    Z. Jankoski; F.C. Lockwood; V. Messerle; E. Karpenko; A. Ustimenko [Imperial College London, London (United Kingdom). Department of Mechanical Engineering

    2003-07-01

    The objective of this study is to simulate the behaviour of pulverized coal in the plasma chamber through numerical experiments carried out with the aid of developed thermodynamic, kinetic and multi dimensional computational fluid dynamics based mathematical models. The data needed for the validation of the numerical procedure were obtained from a cylindrical direct flow burner equipped with a plasmatron (plasma generator) with 100 kW of electric power and mounted on a full-scale boiler (Gusinoozersk TPP, Eastern Siberia). The experiments were carried out using 'Tugnuisk' bituminous coal. Two mathematical models were employed: the one ('1D Plasma-Coal') being one dimensional, but with an emphasis on complex chemistry, the other (3D FAFNIR) being fully three-dimensional with emphasis on the geometry and overall combustion processes. 1D Plasma-Coal numerical experiments gave the predicted temperatures and velocities of gas and solids along the chamber length; while the concentrations of the gas components (CO, CO{sub 2}, H{sub 2}, CH{sub 4}, C{sub 6}H{sub 6}, N{sub 2}, H{sub 2}O) were reported for the chamber exit. The degree of coal gasification showed that 54% of coal carbon was gasified within the plasma chamber. 3D numerical results for plasma jet spreading length were in good agreement with the measured data, while the temperature profiles within the plasma chamber were over predicted. The predictions of main species concentrations reveal that oxygen was completely consumed with the exit product stream consisting of combustible gases, un-burnt volatiles and char particles.

  18. Evaluation of the use of different coals in chemical looping combustion using a bauxite waste as oxygen carrier

    OpenAIRE

    Mendiara, Teresa; García Labiano, Francisco; Gayán Sanz, Pilar; Abad Secades, Alberto; Diego Poza, Luis F. de; Adánez Elorza, Juan

    2013-01-01

    The interest in the use of solid fuels such as coal in Chemical Looping Combustion is growing because of the benefits of the direct use of coal in this technology on the reduction of the costs linked to carbon dioxide capture. In CLC, the oxygen needed for the combustion is supplied by a solid oxygen carrier therefore avoiding the direct contact between fuel and air. Focusing on the use of solid fuels in the In-Situ Gasification Chemical Looping Combustion (iG-CLC), the oxygen ...

  19. Estimate of sulfur, arsenic, mercury, fluorine emissions due to spontaneous combustion of coal gangue: An important part of Chinese emission inventories.

    Science.gov (United States)

    Wang, Shaobin; Luo, Kunli; Wang, Xing; Sun, Yuzhuang

    2016-02-01

    A rough estimate of the annual amount of sulfur, arsenic, mercury and fluoride emission from spontaneous combustion of coal gangue in China was determined. The weighted mean concentrations of S, As, Hg, and F in coal gangue are 1.01%, 7.98, 0.18, and 365.54 mg/kg, respectively. Amounts of S, As, Hg, and F emissions from coal gangue spontaneous combustion show approximately 1.13 Mt, and 246, 45, and 63,298 tons in 2013, respectively. The atmospheric release amount of sulfur from coal gangue is more than one tenth of this from coal combustion, and the amounts of As, Hg, and F are close to or even exceed those from coal combustion. China's coal gangue production growth from 1992 to 2013 show an obvious growth since 2002. It may indicate that Chinese coal gangue has become a potential source of air pollution, which should be included in emission inventories.

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

    Science.gov (United States)

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

    2013-01-01

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

  1. Emission of polycyclic aromatic hydrocarbons from coal and sewage sludge co-combustion in a drop tube furnace.

    Science.gov (United States)

    Han, Jun; Qin, Linbo; Ye, Wei; Li, Yuqi; Liu, Long; Wang, Hao; Yao, Hong

    2012-09-01

    The emission characteristics of polycyclic aromatic hydrocarbons (PAHs) during coal and sewage sludge co-combustion were investigated in a laboratory-scale drop tube furnace. The experimental results demonstrated that coal and sewage sludge co-combustion was beneficial in reducing PAH emissions and PAH toxic equivalent (TEQ) concentrations. Meanwhile, the five-ring PAHs were the main contributor in reducing the concentration of PAHs and TEQ. Moreover, the two- and five-ring PAH concentrations decreased as the mass fraction of sewage sludge in the mixture increased from 0% to 100%. It was also found that PAHs from coal mono-combustion was dominated by the four- and five-ring PAHs. As for the sewage sludge mono-combustion, the three- and four-ring PAHs were the principal components.

  2. Pressurised fluidised bed combustion: an alternative clean coal technology. La combustion en lecho fluido a presion, una alternativa de uso limpio del carbon en desarollo

    Energy Technology Data Exchange (ETDEWEB)

    Bencomo Perez-Zamora, V.; Menendez Perez, J.A.E. (ENDESA, Madrid (Spain))

    1988-11-01

    The primary aim of thistechnology is to reduce emissions of sulphur and nitrous oxides. Pilot plant tests have achieved a sulphur fixing rate of over 95%. Pressurised fluidised bed combustion also has advantages with regard to the emission of contaminants. Halogens, fluorine and chlorine, which in conventional combustion methods are released in the gases, to a large degree remain in the ash as do trace elements, such as arsenic, which usually vapourise at high temperatures in pulverised coal combustors. This technology also has a high output of between 38 and 40% net according to the type of coal used. 10 figs., 10 tabs.

  3. Fireside Corrosion in Oxy-fuel Combustion of Coal

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R [National Energy Technology Laboratory; Tylczak, Joseph [National Energy Technology Laboratory; Meier, Gerald H [University of Pittsburgh; Lutz, Bradley [University of Pittsburgh; Jung, Keeyoung [Institute of Industrial Science and Technology, Korea; Mu, Nan; Yanar, Nazik M [University of Pittsburgh; Pettit, Frederick S [University of Pittsburgh; Zhu, Jingxi [Carnegie Mellon University; Wise, Adam [Carnegie Mellon University; Laughlin, David E. [Carnegie Mellon University; Sridhar, Seetharaman [Carnegie Mellon University

    2013-11-25

    Oxy-fuel combustion is burning a fuel in oxygen rather than air for ease of capture of CO2 from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N2 with CO2 and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe–Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions. Evidence was found for a hreshold for severe attack between 10-4 and 10-3 atm of SO3 at 700ºC.

  4. 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.

  5. Raton Coal Basin boundary, 1999 Coal Resource Assessment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This ArcView shape file contains a polygon representing the extent of the Raton Coal Basin boundary. This theme was created specifically for the National Coal...

  6. Influence of different types of coals and stoves on the emissions of parent and oxygenated PAHs from residential coal combustion in China.

    Science.gov (United States)

    Wang, Yan; Xu, Yue; Chen, Yingjun; Tian, Chongguo; Feng, Yanli; Chen, Tian; Li, Jun; Zhang, Gan

    2016-05-01

    To evaluate the influence of coal property and stove efficiency on the emissions of parent polycyclic aromatic hydrocarbons (pPAHs) and oxygenated PAHs (oPAHs) during the combustion, fifteen coal/stove combinations were tested in this study, including five coals of different geological maturities in briquette and chunk forms burned in two residential stoves. The emission factors (EFs) of pPAHs and oPAHs were in the range of 0.129-16.7 mg/kg and 0.059-0.882 mg/kg, respectively. The geological maturity of coal significantly affected the emissions of pPAHs and oPAHs with the lower maturity coals yielding the higher emissions. The chunk-to-briquette transformation of coal dramatically increased the emissions of pPAHs and oPAHs during the combustion of anthracite, whereas this transformation only elevated the emissions of high molecular weight PAHs for bituminous coals. The influence of stove type on the emissions of pPAHs and oPAHs was also geological-maturity-dependent. High efficiency stove significantly reduced the emissions of PAHs from those relatively high-maturity coals, but its influences on low-maturity coals were inconstant.

  7. Nitrogen oxides, sulfur trioxide, and mercury emissions during oxy-fuel fluidized bed combustion of Victorian brown coal.

    Science.gov (United States)

    Roy, Bithi; Chen, Luguang; Bhattacharya, Sankar

    2014-12-16

    This study investigates, for the first time, the NOx, N2O, SO3, and Hg emissions from combustion of a Victorian brown coal in a 10 kWth fluidized bed unit under oxy-fuel combustion conditions. Compared to air combustion, lower NOx emissions and higher N2O formation were observed in the oxy-fuel atmosphere. These NOx reduction and N2O formations were further enhanced with steam in the combustion environment. The NOx concentration level in the flue gas was within the permissible limit in coal-fired power plants in Victoria. Therefore, an additional NOx removal system will not be required using this coal. In contrast, both SO3 and gaseous mercury concentrations were considerably higher under oxy-fuel combustion compared to that in the air combustion. Around 83% of total gaseous mercury released was Hg(0), with the rest emitted as Hg(2+). Therefore, to control harmful Hg(0), a mercury removal system may need to be considered to avoid corrosion in the boiler and CO2 separation units during the oxy-fuel fluidized-bed combustion using this coal.

  8. Revised users manual, Pulverized Coal Gasification or Combustion: 2-dimensional (87-PCGC-2): Final report, Volume 2. [87-PCGC-2

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.J.; Smoot, L.D.; Brewster, B.S.

    1987-12-01

    A two-dimensional, steady-state model for describing a variety of reactive and non-reactive flows, including pulverized coal combustion and gasification, is presented. Recent code revisions and additions are described. The model, referred to as 87-PCGC-2, is applicable to cylindrical axi-symmetric systems. Turbulence is accounted for in both the fluid mechanics equations and the combustion scheme. Radiation from gases, walls, and particles is taken into account using either a flux method or discrete ordinates method. The particle phase is modeled in a Lagrangian framework, such that mean paths of particle groups are followed. Several multi-step coal devolatilization schemes are included along with a heterogeneous reaction scheme that allows for both diffusion and chemical reaction. Major gas-phase reactions are modeled assuming local instantaneous equilibrium, and thus the reaction rates are limited by the turbulent rate mixing. A NO/sub x/ finite rate chemistry submodel is included which integrates chemical kinetics and the statistics of the turbulence. The gas phase is described by elliptic partial differential equations that are solved by an iterative line-by-line technique. Under-relaxation is used to achieve numerical stability. The generalized nature of the model allows for calculation of isothermal fluid mechanicsgaseous combustion, droplet combustion, particulate combustion and various mixtures of the above, including combustion of coal-water and coal-oil slurries. Both combustion and gasification environments are permissible. User information and theory are presented, along with sample problems. 106 refs.

  9. Assessment of Advanced Coal Gasification Processes

    Science.gov (United States)

    McCarthy, John; Ferrall, Joseph; Charng, Thomas; Houseman, John

    1981-01-01

    This report represents a technical assessment of the following advanced coal gasification processes: AVCO High Throughput Gasification (HTG) Process; Bell Single-Stage High Mass Flux (HMF) Process; Cities Service/Rockwell (CS/R) Hydrogasification Process; Exxon Catalytic Coal Gasification (CCG) Process. Each process is evaluated for its potential to produce SNG from a bituminous coal. In addition to identifying the new technology these processes represent, key similarities/differences, strengths/weaknesses, and potential improvements to each process are identified. The AVCO HTG and the Bell HMF gasifiers share similarities with respect to: short residence time (SRT), high throughput rate, slagging and syngas as the initial raw product gas. The CS/R Hydrogasifier is also SRT but is non-slagging and produces a raw gas high in methane content. The Exxon CCG gasifier is a long residence time, catalytic, fluidbed reactor producing all of the raw product methane in the gasifier. The report makes the following assessments: 1) while each process has significant potential as coal gasifiers, the CS/R and Exxon processes are better suited for SNG production; 2) the Exxon process is the closest to a commercial level for near-term SNG production; and 3) the SRT processes require significant development including scale-up and turndown demonstration, char processing and/or utilization demonstration, and reactor control and safety features development.

  10. Coal blend combustion. Link between unburnt carbon in fly ashes and maceral composition

    Energy Technology Data Exchange (ETDEWEB)

    Helle, Sonia; Alfaro, Guillermo [Instituto de Geologia Economica Aplicada GEA, Universidad de Concepcion, P.O.B. 160-C, Casilla (Chile); Gordon, Alfredo; Garcia, Ximena; Ulloa, Claudia [Departamento de Ingenieria Quimica, Universidad de Concepcion, P.O.B. 160-C, Casilla (Chile)

    2003-03-15

    Coal blends are increasingly utilised at power plants with significant savings and without breaking environment regulations. However, evidence of interaction among the coals requires the study of some parameters that affect combustion efficiency and related opacity of emissions. Actual plant data was available for the combustion of five families of binary blends (single coals and approximately 25%/75%, 50%/50% and 75%/25% blends) with variable contents of ash, volatiles and maceral composition. Size distribution of particles was determined for the coals fed to the plant boilers and the fly ashes, as well as for unburnt carbon in the latter. The almost homogeneously sized feed from different coals generates a size distribution in the fly ash where 250-{mu}m particles vary up to 1.29%, while particles smaller than 38 {mu}m vary between 21.74% and 62.41%. Unburnt carbon increases with size of ash particles from a maximum of 12.2% for fractions smaller than 38 {mu}m up to 73.9% for the fraction bigger than 150 {mu}m. Total content of unburnt carbon in the fly ash from combustion of coal blends show deviations from the expected weighted average of the constituent coals (K, L, T, P, F, S and N). These deviations are related to maceral composition and rank based on reflectance values. The smallest deviation is shown by the blend (T/P) with coals having low values of reflectance and homogeneity of maceral contents. Larger deviations were found for blends K/L, P/F and S/N with higher difference of rank and greater heterogeneity of maceral composition. The K/L, R/N and S/N blends show positive deviations with respect to the expected weighted average, that is, blending was detrimental to the combustion efficiency, while blend P-F showed an enhance of the combustion efficiency as measured by unburnt carbon in the fly ash. A 'reactive maceral index' introduced in this work plays a useful role. If a ratio of reactive maceral index is established for a binary blend as

  11. Coal flotation optimization using modified flotation parameters and combustible recovery in a Jameson cell

    Energy Technology Data Exchange (ETDEWEB)

    Vapur, Hueseyin; Bayat, Oktay [Cukurova University, Mining Engineering Department, Balcali, 01330 Adana (Turkey); Ucurum, Metin [Nigde University, Mining Engineering Department, 51100 Nigde (Turkey)

    2010-10-15

    This study discusses a new coal flotation optimization approach. It is conducted using modified flotation parameters and combustible recovery. The experimental work was evaluated in two stages. In the first stage, recoveries (1, 2, 3, 5 and 8 min of flotation times) of Jameson flotation operating parameters were fitted to first-order kinetic model, R = R{sub {infinity}} [1 - exp (-kt)] where R was recovery at t time, R{sub {infinity}} was ultimate recovery and k was the first-order rate constant to draw the time recovery curves in the experimental study. Two parameters, the ultimate recovery (R{sub {infinity}}) and first-order rate constant (k), were then obtained from the model to fit an experimental time recovery curve. A modified flotation rate constant (K{sub m}) defined as product of R{sub {infinity}} and k, i.e., K{sub m} = R{sub {infinity}}{sup *} k, and selectivity index (SI) defined as the ratio of the modified rate constant of coal to the modified rate constant of ash ((SI)=K{sub m} of Coal/K{sub m} of Ash), which could be collectively called ''modified flotation parameters''. It was used to determine of the sub and upper values of operation variables. In the second one, combustible recovery (%) and ash content (%) were used to optimization of the Jameson flotation variables and it was found that d{sub 80} = 0.250 mm particle size, 1/1 vegetable oil acids/kerosene ratio, 20% solids pulp density, 0.600 L/min wash water rate and 40 cm downcomer immersion dept could be used to separate efficiently coal from ash. Final concentrate was obtained with 94.83% combustible recovery and 17.86% ash content at optimum conditions after 8 min flotation time. (author)

  12. Combustion characteristics of semicokes derived from pyrolysis of low rank bituminous coal

    Institute of Scientific and Technical Information of China (English)

    Qian Wei; Xie Qiang; Huang Yuyi; Dang Jiatao; Sun Kaidi; Yang Qian; Wang Jincao

    2012-01-01

    Various semicokes were obtained from medium-low temperature pyrolysis of Dongrong long flame coal.The proximate analysis,calorific value and Hardgrove grindability index (HGI) of semicokes were determined,and the ignition temperature,burnout temperature,ignition index,burnout index,burnout ratio,combustion characteristic index of semicokes were measured and analyzed using thermogravimetry analysis (TGA).The effects of pyrolysis temperature,heating rate,and pyrolysis time on yield,composition and calorific value of long flame coal derived semicokes were investigated,especially the influence of pyrolysis temperature on combustion characteristics and grindability of the semicokes was studied combined with X-ray diffraction (XRD) analysis of semicokes.The results show that the volatile content,ash content and calorific value of semicokes pyrolyzed at all process parameters studied meet the technical specifications of the pulverized coal-fired furnaces (PCFF) referring to China Standards GB/T 7562-1998.The pyrolysis temperature is the most influential factor among pyrolysis process parameters.As pyrolysis temperature increases,the yield,ignition index,combustion reactivity and burnout index of semicokes show a decreasing tend,but the ash content increases.In the range of 400 and 450 ℃,the grindability of semicokes is rational,especially the grindability of semicokes pyrolyzed at 450 ℃ is suitable.Except for the decrease of volatile content and increase of ash content,the decrease of combustion performance of semicokes pyrolyzed at higher temperature should be attributed to the improvement of the degree of structural ordering and the increase of aromaticity and average crystallite size of char.It is concluded that the semicokes pyrolyzed at the temperature of 450 ℃ is the proper fuel for PCFF.

  13. Cadmium contamination in Tianjin agricultural soils and sediments: relative importance of atmospheric deposition from coal combustion.

    Science.gov (United States)

    Wu, Guanghong; Yang, Cancan; Guo, Lan; Wang, Zhongliang

    2013-06-01

    Cadmium (Cd) in coal, fly ash, slag, atmospheric deposition, soils and sediments collected from Tianjin, northern China, were measured to provide baseline information and determine possible Cd sources and potential risk. The concentrations of Cd in coal, fly ash and atmospheric deposition were much higher than the soil background values. Fallout from coal-fired thermal power plants, heating boilers and industrial furnaces has increased the Cd concentration in soils and sediments in Tianjin. The concentrations of Cd in soils of suburban areas were significantly higher than in rural areas, suggesting that coal burning in Tianjin may have an important impact on the local physical environment. Cd from coal combustion is readily mobilized in soils. It is soluble and can form aqueous complexes and permeate river sediments. The high proportion of mobile Cd affects the migration of Cd in soils and sediments, which may pose an environmental threat in Tianjin due to the exposure to Cd and Cd compounds via the food chain. This study may provide a window for understanding and tracing sources of Cd in the local environment and the risk associated with Cd bioaccessibility.

  14. Effect of biomass blending on coal ignition and burnout during oxy-fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    B. Arias; C. Pevida; F. Rubiera; J.J. Pis [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2008-09-15

    Oxy-fuel combustion is a GHG abatement technology in which coal is burned using a mixture of oxygen and recycled flue gas, to obtain a rich stream of CO{sub 2} ready for sequestration. An entrained flow reactor was used in this work to study the ignition and burnout of coals and blends with biomass under oxy-fuel conditions. Mixtures of CO{sub 2}/O{sub 2} of different concentrations were used and compared with air as reference. A worsening of the ignition temperature was detected in CO{sub 2}/O{sub 2} mixtures when the oxygen concentration was the same as that of the air. However, at an oxygen concentration of 30% or higher, an improvement in ignition was observed. The blending of biomass clearly improves the ignition properties of coal in air. The burnout of coals and blends with a mixture of 79%CO{sub 2}-21%O{sub 2} is lower than in air, but an improvement is achieved when the oxygen concentration is 30 or 35%. The results of this work indicate that coal burnout can be improved by blending biomass in CO{sub 2}/O{sub 2} mixtures. 26 refs., 7 figs., 1 tab.

  15. FutureGen 2.0 Oxy-Coal Combustion Carbon Capture Plant Pre-FEED Design and Cost

    Energy Technology Data Exchange (ETDEWEB)

    Flanigan, Tom; Pybus, Craig; Roy, Sonya; Lockwood, Frederick; McDonald, Denny; Maclnnis, Jim

    2011-09-30

    This report summarizes the results of the Pre-Front End Engineering Design (pre-FEED) phase of a proposed advanced oxy-combustion power generation plant to repower the existing 200 MWe Unit 4 at Ameren Energy Resources’ (AER) Meredosia Power Plant. AER has formed an alliance with Air Liquide Process and Construction, Inc. (ALPC) and Babcock & Wilcox Power Generation Group (B&W PGG) for the design, construction, and testing of the facility, and has contracted with URS Corporation (URS) for preliminary design and Owner’s engineering services. The Project employs oxy-combustion technology – combustion of coal with nearly pure oxygen and recycled flue gas (instead of air) – to capture approximately 90% of the flue gas CO2 for transport and sequestration by another Project. Plant capacity and configuration has been developed based on the B&W PGG-ALPC cool recycle process firing high-sulfur bituminous coal fuel, assuming baseload plant operation to maximize existing steam turbine capability, with limited consideration for plant redundancy and performance optimization in order to keep plant costs as low as practical. Activities and preliminary results from the pre-FEED phase addressed in this report include the following: Overall plant thermal performance; Equipment sizing and system configuration; Plant operation and control philosophy; Plant emissions and effluents; CO2 production and recovery characteristics; Project cost estimate and economic evaluation; Integrated project engineering and construction schedule; Project risk and opportunity assessment; Development of Project permitting strategy and requirements During the Phase 2 of the Project, additional design details will be developed and the Phase 1 work products updated to support actual construction and operation of the facility in Phase 3. Additional information will be provided early in Phase 2 to support Ameren-Environmental in finalizing the appropriate permitting strategies and permit

  16. 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.

  17. 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.

  18. Smog chamber study on the evolution of fume from residential coal combustion.

    Science.gov (United States)

    Geng, Chunmei; Wang, Kun; Wang, Wei; Chen, Jianhua; Liu, Xiaoyu; Liu, Hongjie

    2012-01-01

    Domestic coal stoves are widely used in countryside and greenbelt residents in China for heating and cooking, and emit considerable pollutants to the atmosphere because of no treatment of their exhaust, which can result in deteriorating local air quality. In this study, a dynamic smog chamber was used to investigate the real-time emissions of gaseous and particulate pollutants during the combustion process and a static smog chamber was used to investigate the fume evolution under simulate light irradiation. The real-time emissions revealed that the total hydrocarbon (THC) and CO increased sharply after ignition, and then quickly decreased, indicating volatilization of hydrocarbons with low molecular weight and incomplete combustion at the beginning stage of combustion made great contribution to these pollutants. There was evident shoulder peak around 10 min combustion for both THC and CO, revealing the emissions from vitrinite combustion. Additionally, another broad emission peak of CO after 30 min was also observed, which was ascribed to the incomplete combustion of the inertinite. Compared with THC and CO, there was only one emission peak for NOx, SO2 and particular matters at the beginning stage of combustion. The fume evolution with static chamber simulation indicated that evident consumption of SO2 and NOx as well as new particle formation were observed. The consumption rates for SO2 and NOx were about 3.44% hr(-1) and 3.68% hr(-1), the new particle formation of nuclei particles grew at a rate of 16.03 nm/hr during the first reaction hour, and the increase of the diameter of accumulation mode particles was evident. The addition of isoprene to the diluted mixture of the fume could promote 03 and secondary particle formation.

  19. Smog chamber study on the evolution of fume from residential coal combustion

    Institute of Scientific and Technical Information of China (English)

    Chunmei Geng; Kun Wang; Wei Wang; Jianhua Chen; Xiaoyu Liu; Hongjie Liu

    2012-01-01

    Domestic coal stoves are widely used in countryside and greenbelt residents in China for heating and cooking,and emit considerable pollutants to the atmosphere because of no treatment of their exhaust,which can result in deteriorating local air quality.In this study,a dynamic smog chamber was used to investigate the real-time emissions of gaseous and particulate pollutants during the combustion process and a static smog chamber was used to investigate the fume evolution under simulate light irradiation.The real-time emissions revealed that the total hydrocarbon (THC) and CO increased sharply after ignition,and then quickly decreased indicating volatilization of hydrocarbons with low molecular weight and incomplete combustion at the beginning stage of combustion made great contribution to these pollutants.There was evident shoulder peak around 10 min combustion for both THC and CO,revealing the emissions from vitrinite combustion.Additionally,another broad emission peak of CO after 30 min was also observed,which was ascribed to the incomplete combustion of the inertinite.Compared with THC and CO,there was only one emission peak for NOx,SO2 and particular matters at the beginning stage of combustion.The fume evolution with static chamber simulation indicated that evident consumption of SO2 and NOx as well as new particle formation were observed.The consumption rates for SO2 and NOx were about 3.44% hr-1 and 3.68% hr-1,the new particle formation of nuclei particles grew at a rate of 16.03 nm/hr during the first reaction hour,and the increase of the diameter of accumulation mode particles was evident.The addition of isoprene to the diluted mixture of the fume could promote O3 and secondary particle formation.

  20. Analysis and Processing about Spontaneous Combustion of Coal in Enclosed Circular Coal Yard with Large Coal Reserves%封闭式大储量圆形煤场储煤自燃分析及处理

    Institute of Scientific and Technical Information of China (English)

    金建华; 沈建军; 龚福; 黄健

    2014-01-01

    Due to many spontaneous combustions of coal in enclosed circular coal yard with large coal reserves, it is imminent to know how to prevent and control coal spontaneous combustion.As analysised,the main rea-sons of coal spontaneous combustion are Coal stocks,high coal volatile,increase of coal oxidation layer and water catalytic.So,the keys to prevent and control coal spontaneous combustion are reduce of the contact area of the air and coal,control of moisture content in coal,good ventilation cooling measures and so on.There-fore,,putting forward the establishment of a sound quality management files,“first in first out,burn the old new,regular replacement”,control of the oxygen supply for spontaneous combustion of coal,timely treatment once finding the signs,strict control of time of spontaneous combustion of coal entry storage and measures on how to treat the spontaneous combustion of coal strategy measures can greatly improve the safety factor of the coal yard and the economic benefits of the power plant.%针对燃煤电厂发生多起封闭式大储量圆形煤场储煤自燃问题,如何防止和治理煤炭自燃迫在眉睫。分析认为,煤炭自燃的主要原因是煤场库存量大、煤炭挥发分高、堆煤氧化层增大和水分催化,而减少空气与煤的接触面,控制煤中的水分含量,做好通风散热等措施,是预防和治理圆形煤场储煤自燃的关键。为此,提出建立健全煤质管理档案、“先进先出,烧旧存新,定期置换”、控制煤炭自燃的供氧量、发现自燃征兆及时处理、严控自燃煤的入场堆存时间和处理煤炭自燃的策略等措施,提高煤场的安全运行和电厂的经济效益。

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

    Institute of Scientific and Technical Information of China (English)

    SandroDal-Secco

    2000-01-01

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

  2. The impact of coal combustion residue effluent on water resources: a North Carolina example.

    Science.gov (United States)

    Ruhl, Laura; Vengosh, Avner; Dwyer, Gary S; Hsu-Kim, Heileen; Schwartz, Grace; Romanski, Autumn; Smith, S Daniel

    2012-11-06

    The combustion of coal to generate electricity produces about 130 million tons of coal combustion residues (CCRs) each year in the United States; yet their environmental implications are not well constrained. This study systematically documents the quality of effluents discharged from CCR settling ponds or cooling water at ten sites and the impact on associated waterways in North Carolina, compared to a reference lake. We measured the concentrations of major and trace elements in over 300 samples from CCR effluents, surface water from lakes and rivers at different downstream and upstream points, and pore water extracted from lake sediments. The data show that CCR effluents contain high levels of contaminants that in several cases exceed the U.S. EPA guidelines for drinking water and ecological effects. This investigation demonstrates the quality of receiving waters in North Carolina depends on (1) the ratio between effluent flux and freshwater resource volumes and (2) recycling of trace elements through adsorption on suspended particles and release to deep surface water or pore water in bottom sediments during periods of thermal water stratification and anoxic conditions. The impact of CCRs is long-term, which influences contaminant accumulation and the health of aquatic life in water associated with coal-fired power plants.

  3. Coal selection for NO{sub x} reduction in pulverized fuel combustion

    Energy Technology Data Exchange (ETDEWEB)

    Gibbins, J.R.; Lockwood, F.C.; Man, C.K.; Williamson, J.; Hesselman, G.J.; Downer, B.M.; Skorupska, N.M. [Imperial College of Science, Technology and Medicine, London (United Kingdom)

    1995-12-31

    A major factor affecting a coal`s performance in air-staged low-NO{sub x} burners is the amount of nitrogen remaining in the char after devolatilisation. Current standard proximate devolatilisation tests do not apply realistic heating conditions for PF combustion, but a recently-developed high-temperature wire-mesh reactor now allows relatively simple captive-sample measurements at heating rates of 10{sup 4} K/s. Char nitrogen data is reported for devolatilisation temperatures from 400{degree}C to 1800{degree}C, including values for a range of UK and world-traded coals for which NO{sub x} measurements from three full-scale low-NO{sub x} utility plants and/or a pilot combustor are available. The most general correlation between char nitrogen and combustion NO{sub x} is observed for a peak preparation temperature of 1800{degree}C with 0.15 s (or 2 s) hold time or 1600{degree}C with 2 s hold, conditions which give the maximum release of nitrogen from the char. 18 refs., 8 figs.

  4. Possibility of Reducing Formations of NOx and SO2 Simultaneously during Coal Combustion

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Comparing with other NOx and SO2 control technologies, in-bed reducing NOx and SO2 simultaneously during coal combustion may lower the investment and operation cost. However, there are several possible contradictions between the reduction of NOx and the capture of SO2 during combustion: 1) CO rich atmosphere is favorable for the reduction of NOx, whereas O2 rich favorable for the capture of SO2; 2) higher preheating temperature of coal is favorable for reducing NOx, but unfavorable for reducing SO2; 3) sulphation of some minerals may deactivate their catalytic effect on the reduction of NOx. The attempts to eliminate such contradictions by coating coal granules with thin layer of monometallic oxides and mixed oxides were proposed. Ni2O3 and Fe2O3 showed high activity on NOx reduction and CaO and Cr2O3 showed good effect on sulfur capture. The mixed metallic oxides, e.g., Fe2O3NiO, etc., showed effective for both NOx reduction and SO2 retention. It is possible to in-bed reduce NOx and SO2 simultaneously if the adhering materials are properly chosen to be difunctional materials of both active catalysts for NOx reduction reactions and better sorbents for SO2 retention.

  5. DYNAMICS OF CHANGES IN VEGETATION OF A MODEL EXPERIMENT ON COAL COMBUSTION WASTE DEPOSITS

    Directory of Open Access Journals (Sweden)

    Kazimierz H. Dyguś

    2014-11-01

    Full Text Available The paper contains the evaluation of the reclamation efficiencyon coal combustion waste deposits fertilized with composts and sewage sludge. Based on multiannual studies, the dynamics of changes in vegetation in the performed experiment have been shown. The firstphase of the experiment concerning the reclamation efficiencyof the employed fertilizers was carried out from 2006 to 2007. The second phase was carried out between 2011 and 2012. In order to show a broader spectrum of dynamics of changes in vegetation, the floristicobservation was repeated in 2013 and this paper is the presentation of its outcome. Based on the observation (2011–2013 and its results it was found that apart from plants cultivated in experimental containers also a self-sown florahas had a significantcontribution in shap-ing the vegetation cover. The results of floristic and ecological research have proven that composts and sewage sludge constitute a favorable environment for the development of spontaneous vegetation cover on coal combustion waste deposits. Based on the evaluation of the vegetation cover level in particular models it was shown that models with Complex composts (kC and Radiowo ones (kRa as well as the model with sewage sludge have pre-sented the highest reclamation efficienc. The lowest efficiencyhas been shown in models with ZUSOK composts (kZ and the plant ones (kr. The conclusions have highlighted the share of ecological, systematic and syntaxonomic plant groups in the process of reclamation of combustion waste deposits.

  6. Factors affecting the corrosion rates of ceramics in coal combustion systems

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.P. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-08-01

    The concentrations of approximately a dozen elements in the products of coal combustion affect the corrosion rates of ceramics used to construct the combustion system. The elements, including H, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, and Fe, affect corrosion rates in three ways: as primary corrodants of the materials, as secondary corrodants that affect the activities of the primary corrodants, and by affecting the mass transport rate of the primary corrodants. A full factorial study of corrosion rates performed by varying the concentrations of these elements would involve X{sup n} tests, where X is the number of variations of each element and n is the number of different elements. For three variations (low, medium, and high concentrations) of each of 12 elements, the number of tests is 531,441 for a single temperature and pressure condition. The numbers can be reduced with the use of a fractional factorial test matrix, but the most effective way to perform corrosion tests is to base them on realistic system conditions. In this paper, the effects of the composition and physical state of the products of coal combustion on ceramic corrosion rates are given along with suggestions of appropriate test conditions for specific system components.

  7. Numerical comparison of coal spontaneous combustion danger influenced by different methane drainage patterns in gob area

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong-qing; LIU Xing-kui; ZHANG Ru-ming; ZHANG Sheng-zhu

    2011-01-01

    The influence of gas drainage on float coal spontaneous combustion in the work face with "U" style ventilation was studied. Numerical simulation was used to compare the mutative law of steady flow and density field in the gob area under different drainage conditions by solving the equation set, including mass, momentum, and component transition. Consequently, the sequence of drainage effect and safety was obtained. The result manifests that the more effective the drainage pattern is, the easier float coal spontaneous combustion is caused due to air being guided into the depth of the gob area when the drainage position is arranged in the gas accumulation area. If the widened scope of oxidation zone exceeds the upper limit of the work face advancing speed, nitrogen injection should be applied to decrease the probability of spontaneous combustion. Then, the pipe laying drainage in the upper angle is most economical and safe compared with other drainage patterns when only the situation of gas accumulation is controlled in the upper angle. Finally, drainage pressure must not be too great. Otherwise the drainage density will decrease even if hazard is caused by back flow possibly happening in the return outlet when the drainage position is arranged near the work face.

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

    Science.gov (United States)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk

    2010-04-01

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

  9. Volatilization behavior of Cd and Zn based on continuous emission measurement of flue gas from laboratory-scale coal combustion.

    Science.gov (United States)

    Liu, J; Falcoz, Q; Gauthier, D; Flamant, G; Zheng, C Z

    2010-06-01

    The accumulation of toxic metals generated by coal-fired power stations presents a serious threat to the environment. The volatilization behavior of two representative metals (Cd and Zn), and the influence of temperature were investigated during coal combustion. An inductively coupled plasma atomic emission spectrometric (ICP-AES) method was developed to continuously measure the heavy metal concentrations quantitatively in flue gas under combustion conditions in order to track the metal release process. This continuous heavy metal analysis system was implemented by coupling it to two types of high temperature reactors: a bubbling fluidized bed reactor and a fixed bed reactor with diameter of 0.1 m and 0.08 m respectively. For the two metals considered in this study (Cd and Zn), the experimental setup was successfully used to continuously monitor the metal vaporization process during coal combustion independent of reactor design, and at different temperatures. Cd is more easily vaporized than Zn during coal combustion. Temperature significantly influences the metal vaporization process. In general, the higher the temperature, the higher the metal vaporization, although the vaporization is not proportional to temperature. In addition to the experimental study, a thermodynamic calculation was carried out to simulate the heavy metal speciation during coal combustion process. The theoretical volatilization tendency is consistent with the experiment. The thermodynamic calculation identified the formation of binary oxides retarding heavy metal vaporization.

  10. Emission of volatile organic compounds from domestic coal stove with the actual alternation of flaming and smoldering combustion processes.

    Science.gov (United States)

    Liu, Chengtang; Zhang, Chenglong; Mu, Yujing; Liu, Junfeng; Zhang, Yuanyuan

    2017-02-01

    Volatile organic compounds (VOCs) emissions from the chimney of a prevailing domestic stove fuelled with raw bituminous coal were measured under flaming and smoldering combustion processes in a farmer's house. The results indicated that the concentrations of VOCs quickly increased after the coal loading and achieved their peak values in a few minutes. The peak concentrations of the VOCs under the smoldering combustion process were significantly higher than those under the flaming combustion process. Alkanes accounted for the largest proportion (43.05%) under the smoldering combustion, followed by aromatics (28.86%), alkenes (21.91%), carbonyls (5.81%) and acetylene (0.37%). The emission factors of the total VOCs under the smoldering combustion processes (5402.9 ± 2031.8 mg kg(-1)) were nearly one order of magnitude greater than those under the flaming combustion processes (559.2 ± 385.9 mg kg(-1)). Based on the VOCs emission factors obtained in this study and the regional domestic coal consumption, the total VOCs emissions from domestic coal stoves was roughly estimated to be 1.25 × 10(8) kg a(-1) in the Beijing-Tianjin-Hebei region.

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

    Science.gov (United States)

    Kolker, Allan; Senior, Constance L.; van Alphen, Chris

    2014-12-15

    Mercury (Hg) analyses were obtained for 42 samples of feed coal provided by Eskom, the national electric utility of South Africa, representing all 13 coal-fired power stations operated by Eskom in South Africa. This sampling includes results for three older power stations returned to service starting in the late 2000s. These stations were not sampled in the most recent previous study. Mercury concentrations determined in the present study are similar to or slightly lower than those previously reported, and input Hg for the three stations returned to service is comparable to that for the other 10 power stations. Determination of halogen contents of the 42 feed coals confirms that chlorine contents are generally low, and as such, the extent of Hg self-capture by particulate control devices (PCDs) is rather limited. Eight density separates of a South African Highveld (#4) coal were also provided by Eskom, and these show a strong mineralogical association of Hg (and arsenic) with pyrite. The density separates were used to predict Hg and ash contents of coal products used in South Africa or exported. A suite of 48 paired samples of pulverization-mill feed coal and fly ash collected in a previous (2010) United Nations Environment Programme-sponsored study of emissions from the Duvha and Kendal power stations was obtained for further investigation in the present study. These samples show that in each station, Hg capture varies by boiler unit and confirms that units equipped with fabric filters for air pollution control are much more effective in capturing Hg than those equipped with electrostatic precipitators. Apart from tracking the performance of PCDs individually, changes resulting in improved mercury capture of the Eskom fleet are discussed. These include Hg reduction through coal selection and washing, as well as through optimization of equipment and operational parameters. Operational changes leading to increased mercury capture include increasing mercury

  12. Assessment of Literature Related to Combustion Appliance Venting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Vi H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Stratton, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wray, Craig P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-06-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is constrained by concerns about related impacts on the safety of naturally vented combustion appliances. Tighter housing units more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spillage. Several test methods purportedly assess the potential for depressurization-induced backdrafting and spillage, but these tests are not robustly reliable and repeatable predictors of venting performance, in part because they do not fully capture weather effects on venting performance. The purpose of this literature review is to investigate combustion safety diagnostics in existing codes, standards, and guidelines related to combustion appliances. This review summarizes existing combustion safety test methods, evaluations of these test methods, and also discusses research related to wind effects and the simulation of vent system performance. Current codes and standards related to combustion appliance installation provide little information on assessing backdrafting or spillage potential. A substantial amount of research has been conducted to assess combustion appliance backdrafting and spillage test methods, but primarily focuses on comparing short-term (stress) induced tests and monitoring results. Monitoring, typically performed over one week, indicated that combinations of environmental and house operation characteristics most conducive to combustion spillage were rare. Research, to an extent, has assessed existing combustion safety diagnostics for house depressurization, but the objectives of the diagnostics, both stress and monitoring, are not clearly defined. More research is also needed to quantify the frequency of test “failure” occurrence throughout the building stock and assess the statistical effects of weather (especially wind) on house depressurization and in turn on combustion appliance venting

  13. CHAR CRYSTALLINE TRANSFORMATIONS DURING COAL COMBUSTION AND THEIR IMPLICATIONS FOR CARBON BURNOUT

    Energy Technology Data Exchange (ETDEWEB)

    ROBERT H. HURT

    1998-09-08

    temperatures approaching 3000 o C. For the measurement of temperature histories an optical diagnostic is being developed that offers sufficient spatial resolution to distinguish the sample temperature from the substrate temperature. The optical diagnostic is based on a CID camera, a high-power lens, and movable mirrors to projecting multiple, filtered images onto a single chip. Oxidation kinetics are measured on the heat treated samples by a nonisothermal TGA technique. Task 2 Thermal deactivation kinetics. The goal of this task is to quantify thermal char deactivation as a function of temperature history and parent coal, with an emphasis on inert environments at temperatures and times found in combustion systems. The results are to be cast in the form of deactivation kinetics useful for incorporation in combustion models. Task 3 Crystal structure characterization. Crystal structure characterization provides important insight into the mechanisms of thermal char deactivation, and the degree of crystalline transformations has shown a strong correlation with reactivity changes in recent combustion studies [Davis et al., 1992, Beeley et al., 1996]. This task seeks to improve our understanding of char carbon crystalline transformations under combustion conditions by analyzing a large set of HRTEM fringe images for a series of flame-generated chars whose reactivities have been previously reported [Hurt et al., 1995, Beeley et al., 1996]. As a first step, a new technique is being developed for the quantitative analysis of fringe images, extending previous work to allow measurement of a complete set of crystal structure parameters including mean layer size, mean stacking height, interlayer spacing, layer curvature, amorphous fraction, and degree of anisotropy. The resulting database will revealing, at a very fundamental level, the basic differences in char crystal structure due to parent coal rank and to temperature history in the range of interest to combustion systems.

  14. Evaluation of a sequential extraction process used for determining mercury binding mechanisms to coal combustion byproducts.

    Science.gov (United States)

    Noel, James D; Biswas, Pratim; Giammar, Daniel E

    2007-07-01

    Leaching of mercury from coal combustion byproducts is a concern because of the toxicity of mercury. Leachability of mercury can be assessed by using sequential extraction procedures. Sequential extraction procedures are commonly used to determine the speciation and mobility of trace metals in solid samples and are designed to differentiate among metals bound by different mechanisms and to different solid phases. This study evaluated the selectivity and effectiveness of a sequential extraction process used to determine mercury binding mechanisms to various materials. A six-step sequential extraction process was applied to laboratory-synthesized materials with known mercury concentrations and binding mechanisms. These materials were calcite, hematite, goethite, and titanium dioxide. Fly ash from a full-scale power plant was also investigated. The concentrations of mercury were measured using inductively coupled plasma (ICP) mass spectrometry, whereas the major elements were measured by ICP atomic emission spectrometry. The materials were characterized by X-ray powder diffraction and scanning electron microscopy with energy dispersive spectroscopy. The sequential extraction procedure provided information about the solid phases with which mercury was associated in the solid sample. The procedure effectively extracted mercury from the target phases. The procedure was generally selective in extracting mercury. However, some steps in the procedure extracted mercury from nontarget phases, and others resulted in mercury redistribution. Iron from hematite and goethite was only leached in the reducible and residual extraction steps. Some mercury associated with goethite was extracted in the ion exchangeable step, whereas mercury associated with hematite was extracted almost entirely in the residual step. Calcium in calcite and mercury associated with calcite were primarily removed in the acid-soluble extraction step. Titanium in titanium dioxide and mercury adsorbed onto

  15. What should be the apparent viscosity target of a coal-water slurry fuel for combustion?

    Energy Technology Data Exchange (ETDEWEB)

    Pisupati, S.V.; Morrison, J.L.; Scaroni, A.W. [Pennsylvania State Univ., University Park, PA (United States)

    1997-12-31

    The rheological properties of a coal water slurry fuel (CWSF) affect its handling, atomization, and combustion behavior. The flow behavior and apparent viscosity are two rheological properties that are often specified by the end user. A pseudoplastic (shear thinning) flow behavior is preferred since there is a decrease in the apparent viscosity as the fuel is pumped to, and then atomized into the boiler. Specifying an apparent viscosity target for the CWSF is more problematic since there are often competing forces to maximize the solids loading of the fuel while minimizing the apparent viscosity. The apparent viscosity is a function of the particle size distribution of the coal, the solids loading of the CWSF, the physical and chemical properties of the coal, and the additive package used to prepare the CWSF. Targeting an apparent viscosity is necessary during the formulation and production of a CWSF. The trade off between maximizing the solids loading in order to increase the BTU content and maintaining an acceptable apparent viscosity to ensure good atomization behavior is not well established. In order to better define this trade-off, an investigation was carried out to examine the interrelationship between solids loading, apparent viscosity, atomization behavior, and the combustion performance of a CWSF. The CWSF was prepared in a continuous ball mill and isolated in a storage tank. Small batches of CWSF were taken from the storage tank and then diluted to determine how the changes in the CWSF`s rheology and solids loading affected it`s atomization and combustion behavior.

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

    Energy Technology Data Exchange (ETDEWEB)

    Flour, I.; Dal Secco, S.

    1995-10-01

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

  17. 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.

  18. Combined-cycle power stations using ``clean-coal-technologies``: Thermodynamic analysis of full gasification vs. fluidized bed combustion with partial gasification

    Energy Technology Data Exchange (ETDEWEB)

    Lozza, G.; Chiesa, P. [Politecnico di Milano, Milan (Italy). Dept. of Energetics; DeVita, L. [Eniricerche, Milan (Italy)

    1994-12-31

    A novel class of power plants for clean conversion of coal into power has been recently proposed, based on the concept of partial coal gasification and fluidized-bed combustion of unconverted char from gasification. This paper focuses on the thermodynamic aspects of these plants, in comparison with full gasification cycles, assessing their performance on the basis of a common advanced power plant technology level. Several plant configurations are considered, including pressurized or atmospheric fluidized-bed, air- or steam-cooled, with different carbon conversion in the gasifier. The calculation method, used for reproducing plant energy balances and for performance prediction, is described in the paper. A complete second-law analysis is carried out, pointing out the efficiency loss breakdown for both technologies. Results show that partial gasification plants can achieve efficiencies consistently higher than IGCC, depending on plant configuration and carbon conversion, making this solution a viable and attractive option for efficient coal utilization.

  19. Combined-cycle power stations using clean-coal technologies: Thermodynamic analysis of full gasification versus fluidized bed combustion with partial gasification

    Energy Technology Data Exchange (ETDEWEB)

    Lozza, G.; Chiesa, P. [Politecnico di Milano, Milan (Italy). Dept. of Energetics; DeVita, L. [Eniricerche, Milan (Italy)

    1996-10-01

    A novel class of power plants for clean conversion of coal into power has been recently proposed, based on the concept of partial coal gasification and fluidized-bed combustion of unconverted char from gasification. This paper focuses on the thermodynamic aspects of these plants, in comparison with full gasification cycles, assessing their performance on the basis of a common advanced power plant technology level. Several plant configurations are considered, including pressurized or atmospheric fluidized-bed, air- or steam-cooled, with different carbon conversion in the gasifier. The calculation method, used for reproducing plant energy balances and for performance prediction, is described in the paper. A complete second-law analysis is carried out, pointing out the efficiency loss breakdown for both technologies. Results show that partial gasification plants can achieve efficiencies consistently higher than IGCC, depending on plant configuration and carbon conversion, making this solution a viable and attractive option for efficient coal utilization.

  20. Regenerable sorbents for mercury capture in simulated coal combustion flue gas.

    Science.gov (United States)

    Rodríguez-Pérez, Jorge; López-Antón, M Antonia; Díaz-Somoano, Mercedes; García, Roberto; Martínez-Tarazona, M Rosa

    2013-09-15

    This work demonstrates that regenerable sorbents containing nano-particles of gold dispersed on an activated carbon are efficient and long-life materials for capturing mercury species from coal combustion flue gases. These sorbents can be used in such a way that the high investment entailed in their preparation will be compensated for by the recovery of all valuable materials. The characteristics of the support and dispersion of gold in the carbon surface influence the efficiency and lifetime of the sorbents. The main factor that determines the retention of mercury and the regeneration of the sorbent is the presence of reactive gases that enhance mercury retention capacity. The capture of mercury is a consequence of two mechanisms: (i) the retention of elemental mercury by amalgamation with gold and (ii) the retention of oxidized mercury on the activated carbon support. These sorbents were specifically designed for retaining the mercury remaining in gas phase after the desulfurization units in coal power plants.

  1. Influence of constricted air distribution on NOx emissions in pulverized coal combustion boiler

    Institute of Scientific and Technical Information of China (English)

    WEI Feng(魏风); ZHANG Jun-ying(张军营); TANG Bi-guang(唐必光); ZHENG Chu-guang(郑楚光)

    2003-01-01

    This paper reports a field testing of full scale PCC (Pulverized Coal Combustion) boiler study into the influence of constricted air distribution on NOx emissions at unit 3 (125 MW power units, 420 t/h boiler) of Guixi power station, Jiangxi and puts forward the methods to decrease NOx emissions and the principle of boiler operation and regulation through analyzing NOx emissions state under real running condition. Based on boiler constricted air distribution, the experiment mainly tested the influence of primary air, excessive air, boiler load and milling sets (tertiary air) on NOx emissions and found its influence characteristics. A degraded bituminous coal is simply adopted to avoid the test results from other factors.

  2. Development of a database management system for Coal Combustion By-Products (CCBs)

    Energy Technology Data Exchange (ETDEWEB)

    O`Leary, E.M.; Peck, W.D.; Pflughoeft-Hassett, D.F. [and others

    1997-06-01

    Coal combustion by-products (CCBs) are produced in high volumes worldwide. Utilization of these materials is economically and environmentally advantageous and is expected to increase as disposal costs increase. The American Coal Ash Association (ACAA) is developing a database to contain characterization and utilization information on CCBs. This database will provide information for use by managers, marketers, operations personnel, and researchers that will aid in their decision making and long-term planning for issues related to CCBs. The comprehensive nature of the database and the interactive user application will enable ACAA members to efficiently and economically access a wealth of data on CCBs and will promote the technically sound, environmentally safe, and commercially competitive use of CCBs.

  3. Boron and strontium isotopic characterization of coal combustion residuals: validation of new environmental tracers.

    Science.gov (United States)

    Ruhl, Laura S; Dwyer, Gary S; Hsu-Kim, Heileen; Hower, James C; Vengosh, Avner

    2014-12-16

    In the U.S., coal fired power plants produce over 136 million tons of coal combustion residuals (CCRs) annually. CCRs are enriched in toxic elements, and their leachates can have significant impacts on water quality. Here we report the boron and strontium isotopic ratios of leaching experiments on CCRs from a variety of coal sources (Appalachian, Illinois, and Powder River Basins). CCR leachates had a mostly negative δ(11)B, ranging from -17.6 to +6.3‰, and (87)Sr/(86)Sr ranging from 0.70975 to 0.71251. Additionally, we utilized these isotopic ratios for tracing CCR contaminants in different environments: (1) the 2008 Tennessee Valley Authority (TVA) coal ash spill affected waters; (2) CCR effluents from power plants in Tennessee and North Carolina; (3) lakes and rivers affected by CCR effluents in North Carolina; and (4) porewater extracted from sediments in lakes affected by CCRs. The boron isotopes measured in these environments had a distinctive negative δ(11)B signature relative to background waters. In contrast (87)Sr/(86)Sr ratios in CCRs were not always exclusively different from background, limiting their use as a CCR tracer. This investigation demonstrates the validity of the combined geochemical and isotopic approach as a unique and practical identification method for delineating and evaluating the environmental impact of CCRs.

  4. Multi-objective Optimization of Coal-fired Boiler Combustion Based on NSGA-II

    Directory of Open Access Journals (Sweden)

    Tingfang Yu

    2013-06-01

    Full Text Available NOx emission characteristics and overall heat loss model for a 300MW coal-fired boiler were established by Back Propagation (BP neural network, by which the the functional relationship between outputs (NOx emissions & overall heat loss of the boiler and inputs (operational parameters of the boiler of a coal-fired boiler can be predicted. A number of field test data from a full-scale operating 300MWe boiler were used to train and verify the BP model. The NOx emissions & heat loss predicted by the BP neural network model showed good agreement with the measured. Then, BP model and the non-dominated sorting genetic algorithm II (NSGA-II were combined to gain the optimal operating parameters which lead to lower NOx emissions and overall heat loss boiler. The optimization results showed that hybrid algorithm by combining BP neural network with NSGA-II can be a good tool to solve the problem of multi-objective optimization of a coal-fired combustion, which can reduce NOx emissions and overall heat loss effectively for the coal-fired boiler.

  5. Chemical Fixation of CO2 in Coal Combustion Products and Recycling through Biosystems

    Energy Technology Data Exchange (ETDEWEB)

    C. Henry Copeland; Paul Pier; Samantha Whitehead; David Behel

    2001-09-30

    This Annual Technical Progress Report presents the principle results in enhanced growth of algae using coal combustion products as a catalyst to increase bicarbonate levels in solution. A co-current reactor is present that increases the gas phase to bicarbonate transfer rate by a factor of five to nine. The bicarbonate concentration at a given pH is approximately double that obtained using a control column of similar construction. Algae growth experiments were performed under laboratory conditions to obtain baseline production rates and to perfect experimental methods. The final product of this initial phase in algae production is presented.

  6. Cleaner phosphogypsum, coal combustion ashes and waste incineration ashes for application in building materials: A review

    Energy Technology Data Exchange (ETDEWEB)

    L. Reijnders [University of Amsterdam, Amsterdam (Netherlands)

    2007-02-15

    Application of phosphogypsum, coal combustion ashes and waste incineration ashes in building materials has been limited by the presence of minor components that are hazardous, such as radioactive substances, chlorinated dioxins and heavy metals, or have a negative impact on product quality or production economics, such as phosphate, fluoride, carbon and chloride. Source reduction, destruction of persistent organics and separation techniques may reduce the concentrations of such components. With a few exceptions, separation techniques currently lead to significantly higher (private) costs. Higher waste disposal costs, tighter regulations and higher prices for competing virgin minerals could make the use of the purified phosphogypsum and ashes in building materials more attractive.

  7. Numerical simulation of excess-enthalpy combustion flame propagation of coal mine methane in ceramic foam

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the assumption of a local non-equilibrium of heat transfer between a solid matrix and gas,a mathematic model of coal mine methane combustion in a porous medium was established,as well the solid-gas boundary conditions.We simulated numerically the flame propagation characteristics.The results show that the flame velocity in ceramic foam is higher than that of free laminar flows;the maximum flame velocity depends on the combined effects of a radiation extinction coefficient and convection heat transf...

  8. Transformations of inorganic coal constituents in combustion systems. Volume 3, Appendices: Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bradley R. [Univ. of Utah, Salt Lake City, UT (United States); Fry, Andrew R. [Univ. of Utah, Salt Lake City, UT (United States); Senior, Constance L. [Univ. of Utah, Salt Lake City, UT (United States); Shim, Hong Shig [Univ. of Utah, Salt Lake City, UT (United States); Otten, Brydger Van [Univ. of Utah, Salt Lake City, UT (United States); Wendt, Jost [Univ. of Utah, Salt Lake City, UT (United States); Shaddix, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tree, Dale [Brigham Young Univ., Provo, UT (United States)

    2010-06-01

    This report summarizes Year 2 results of a research program designed to use multi-scale experimental studies and fundamental theoretical models to characterize and predict the impacts of retrofit of existing coal-fired utility boilers for oxy-combustion. Year 2 focused extensively on obtaining experimental data from the bench-scale, lab-scale and pilot-scale reactors. These data will be used to refine and validate submodels to be implemented in CFD simulations of full-scale boiler retrofits. Program tasks are on schedule for Year 3 completion. Both Year 2 milestones were completed on schedule and within budget.

  10. Combustion characteristics of low concentration coal mine methane in divergent porous media burner

    Institute of Scientific and Technical Information of China (English)

    Lin Baiquan; Dai Huaming⇑; Wang Chaoqun; Li Qingzhao; Wang Ke; Zheng Yuanzhen

    2014-01-01

    Low-concentration methane (LCM) has been one of the biggest difficulties in using coal mine methane. And previous studies found that premixed combustion in porous media is an effective method of low cal-orific gas utilization. This paper studied the combustion of LCM in a divergent porous medium burner (DPMB) by using computational fluid dynamics (CFD), and investigated the effect of gas initial tempera-ture on combustion characteristic, the distribution of temperature and pollutant at different equivalence ratios in detail. Besides, the comparison of divergent and cylindrical burners was also performed in this paper. The results show that:the peak temperature in DPMB increases as the increasing of equivalence ratio, which is also suitable for the outlet NO discharge;the linear correlation is also discovered between peak temperature and equivalence ratios;NO emission at the initial temperature of 525 K is 5.64 times, larger than NO emission at the initial temperature of 300 K. Thus, it is preferable to balance the effect of thermal efficiency and environment simultaneously when determining the optimal initial temperature range. The working parameter limits of divergent burner are wider than that of cylindrical one which contributes to reducing the influence of LCM concentration and volume fluctuation on combustion.

  11. Health Effects of Subchronic Inhalation of Simulated Downwind Coal Combustion Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Joe Mauderly

    2009-01-07

    The purpose of this project was to conduct a comprehensive laboratory-based evaluation of selected respiratory and cardiac health hazards of subchronic (up to 6 months) inhalation of simulated key components of 'downwind plume' emissions of coal combustion. This project was performed as an integral part of a joint government-industry program termed the 'National Environmental Respiratory Center' (NERC), which is aimed at disentangling the roles of different physical-chemical air pollutants and their sources in the health effects associated statistically with air pollution. The characterization of the exposure atmosphere and the health assays were identical to those employed in the NERC protocols used to evaluate other pollution source emissions, such as diesel, gasoline, and wood combustion. The project had two phases, each encompassing multiple tasks. Guidelines for the composition of the exposure atmosphere were set by consensus of an expert workshop. Development of the capability to generate the exposure atmosphere and pilot studies of the comparative exposure composition using two coal types were accomplished in Phase 1. In Phase 2, the toxicological study was conducted using Powder River Basin Sub-bituminous coal. NETL provided 50% support for the work in Phase 1 and had intended to provide 20% support for the work in Phase 2. Phase 1 is completed and Phase 2 is in the final stages. All animal exposures were completed without incident, and the composition of the exposure atmospheres met the targets. All of the health sample collections are completed, but some samples remain to be analyzed. Data summaries and final statistical analysis of results remain to be completed. The goal is to submit all publications before the end of FY-08. Repeated exposure to simulated downwind coal emissions caused some significant health effects, but the number of effects tended to be fewer than those caused by the other NERC exposures (diesel and gasoline

  12. Effect of coal combustion fly ash use in concrete on the mass transport release of constituents of potential concern.

    Science.gov (United States)

    Garrabrants, Andrew C; Kosson, David S; DeLapp, Rossane; van der Sloot, Hans A

    2014-05-01

    Concerns about the environmental safety of coal combustion fly ash use as a supplemental cementitious material have necessitated comprehensive evaluation of the potential for leaching concrete materials containing fly ash used as a cement replacement. Using concrete formulations representative of US residential and commercial applications, test monoliths were made without fly ash replacement (i.e., controls) and with 20% or 45% of the portland cement fraction replaced by fly ash from four coal combustion sources. In addition, microconcrete materials were created with 45% fly ash replacement based on the commercial concrete formulation but with no coarse aggregate and an increased fine aggregate fraction to maintain aggregate-paste interfacial area. All materials were cured for 3 months prior to mass transport-based leach testing of constituents of potential concern (i.e., Sb, As, B, Ba, Cd, Cr, Mo, Pb, Se, Tl and V) according to EPA Method 1315. The cumulative release results were consistent with previously tested samples of concretes and mortars from international sources. Of the 11 constituents tested, only Sb, Ba, B, Cr and V were measured in quantifiable amounts. Microconcretes without coarse aggregate were determined to be conservative surrogates for concrete in leaching assessment since cumulative release from microconcretes were only slightly greater than the associated concrete materials. Relative to control materials without fly ash, concretes and microconcretes with fly ash replacement of cement had increased 28-d and 63-d cumulative release for a limited number 10 comparison cases: 2 cases for Sb, 7 cases for Ba and 1 case for Cr. The overall results suggest minimal leaching impact from fly ash use as a replacement for up to 45% of the cement fraction in typical US concrete formulations; however, scenario-specific assessment based on this leaching evaluation should be used to determine if potential environmental impacts exist.

  13. Mercury and halogens in coal--Their role in determining mercury emissions from coal combustion

    Science.gov (United States)

    Kolker, Allan; Quick, Jeffrey C.; Senior, Connie L.; Belkin, Harvey E.

    2012-01-01

    Mercury is a toxic pollutant. In its elemental form, gaseous mercury has a long residence time in the atmosphere, up to a year, allowing it to be transported long distances from emission sources. Mercury can be emitted from natural sources such as volcanoes, or from anthropogenic sources, such as coal-fired powerplants. In addition, all sources of mercury on the Earth's surface can re-emit it from land and sea back to the atmosphere, from which it is then redeposited. Mercury in the atmosphere is present in such low concentrations that it is not considered harmful. Once mercury enters the aquatic environment, however, it can undergo a series of biochemical transformations that convert a portion of the mercury originally present to methylmercury, a highly toxic organic form of mercury that accumulates in fish and birds. Many factors contribute to creation of methylmercury in aquatic ecosystems, including mercury availability, sediment and nutrient load, bacterial influence, and chemical conditions. In the United States, consumption of fish with high levels of methylmercury is the most common pathway for human exposure to mercury, leading the U.S. Environmental Protection Agency (EPA) to issue fish consumption advisories in every State. The EPA estimates that 50 percent of the mercury entering the atmosphere in the United States is emitted from coal-burning utility powerplants. An EPA rule, known as MATS (for Mercury and Air Toxics Standards), to reduce emissions of mercury and other toxic pollutants from powerplants, was signed in December 2011. The rule, which is currently under review, specifies limits for mercury and other toxic elements, such as arsenic, chromium, and nickel. MATS also places limits on emission of harmful acid gases, such as hydrochloric acid and hydrofluoric acid. These standards are the result of a 2010 detailed nationwide program by the EPA to sample stack emissions and thousands of shipments of coal to coal-burning powerplants. The United

  14. Predictions of full-scale NO{sub x} emissions and LOI from coal and coal blends in pilot combustion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Monroe, L.S. [Southern Research Institute, Birmingham, AL (United States); Clarkson, R.J. [Southern Company Services, Inc., Birmingham, AL (United States); Stallings, J.W. [Electric Power Research Institute, Palo Alto, CA (United States)

    1995-03-01

    A research program designed to predict the NO{sub x} emissions and unburned carbon levels from low sulfur CAAA compliance coals in low NO{sub x} firing is continuing. Sponsored by Alabama Power and EPRI, the program is performed in the Southern Company and Southern Research Institute pilot-scale combustion facility. The coals are tested in the pilot furnace and predictions for the full-scale plants are made from the pilot data. In this paper, results relating to predicting NO{sub x} emissions and LOI for a coal blend from results on the parent coals are presented. Also, five different grinds of a Venezuelan coal, known to be particularly difficult to burn out, were burned with a low NO{sub x} burner. The LOI and NO{sub x} results for the various grinds are shown.

  15. 圆形煤场自燃解决方案%Solutions for Spontaneous Combustion in Round Coal Yards

    Institute of Scientific and Technical Information of China (English)

    潘宏生

    2014-01-01

    近年环保要求严苛,圆形煤场因其突出优点成为趋势,但煤场管理问题也逐渐显现,煤炭自燃问题时有发生。根据多年生产经验对圆形煤场自燃控制方法进行阐述。%In recent years, the requirement for environmental protection is stringent, so the round coal yards are becoming the trend for their outstanding advantages. However, the problems in coal yard management are becoming increasingly apparent, and spontaneous combustion of coal occurs from time to time. The control methods of spontaneous combustion of round coal yards are elaborated based on years of production experience.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-01

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

  17. 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

  18. Co-combustion of bituminous coal and biomass fuel blends: Thermochemical characterization, potential utilization and environmental advantage.

    Science.gov (United States)

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui

    2016-10-01

    The thermochemical characteristics and gaseous trace pollutant behaviors during co-combustion medium-to-low ash bituminous coal with typical biomass residues (corn stalk and sawdust) were investigated. Lowering of ignition index, burnout temperature and activation energy in the major combustion stage are observed in the coal/biomass blends. The blending proportion of 20% and 30% are regarded as the optimum blends for corn stalk and sawdust, respectively, in according the limitations of heating value, activation energy, flame stability and base/acid ratio. The reductions of gaseous As, Cd, Cu, Pb, Zn and polycyclic aromatic hydrocarbon (PAHs) were 4.5%, 7.8%, 6.3%, 9.8%, 9.4% and 17.4%, respectively, when co-combustion coal with 20% corn stalk. The elevated capture of trace elements were found in coal/corn stalk blend, while the coal/sawdust blend has the better PAHs control potential. The reduction mechanisms of gaseous trace pollutants were attributed to the fuel property, ash composition and relative residence time during combustion.

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

    OpenAIRE

    2016-01-01

    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 ...

  20. Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David

    2013-09-30

    The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

  1. Experimental studies on Gas—Particle Flows and Coal Combustion in New Generation Spouting—Cyclone COmbustor

    Institute of Scientific and Technical Information of China (English)

    D.X.Wang; Z.H.Ma; 等

    1996-01-01

    Besed on previous studies,an improved non-slagging spouting-cyclone combustor with two-stage combustion,organized in perpendicularly vortexing flows,is developed for clean coal combustion applied is small-size industrial furnaces and domestic furnaces.The isothermal model test and the combustion test give some encouraging results.In this study,further improvement of the gemoetrical configuration was made,a visualization method and a LDA system were used to study the gas-particle flow behavior and the temperature and gas composition in combustion experiments were measured by using thermocouples and a COSA-6000-CD Portable Stack Analyzer.Stronger recirculation in the sopouting zone and the strongly swirling efect in the cyclone zone were obtained in the improved combustor.The combustion temperature distribution is uniform.These results indicate that the improved geometrical configuration of the combustor is favorable to the stabilization of coal flame and the intensification of coal combustion.and is provides a basis for the practical application of this technique.

  2. Analysis of naturally-occurring radionuclides in coal combustion fly ash, gypsum, and scrubber residue samples.

    Science.gov (United States)

    Roper, Angela R; Stabin, Michael G; Delapp, Rossane C; Kosson, David S

    2013-03-01

    Coal combustion residues from coal-fired power plants can be advantageous for use in building and construction materials. These by-products contain trace quantities of naturally occurring radionuclides from the uranium and thorium series, as well as other naturally occurring radionuclides such as K. Analysis was performed on samples of coal fly ash, flue gas desulfurization, gypsum and scrubber sludges, fixated scrubber sludges, and waste water filter cakes sampled from multiple coal-fired power plants in the United States. The radioactive content of U and Th decay series nuclides was determined using gamma photopeaks from progeny Pb at 352 keV and Tl at 583 keV, respectively; K specific activities were determined using the 1,461 keV photopeak. The samples were hermetically sealed to allow for secular equilibrium between the radium parents and the radon and subsequent progeny. Samples were analyzed in a common geometry using two high purity germanium photon detectors with low energy detection capabilities. The specific activities (Bq kg) were compared to results from literature studies including different building materials and fly ash specific activities. Fly ash from bituminous and subbituminous coals had U specific activities varying from 30-217 Bq kg (mean + 1 s.d. 119 ± 45 Bq kg) and 72-209 Bq kg (115 ± 40 Bq kg), respectively; Th specific activities from 10-120 Bq kg (73 ± 26 Bq kg) and 53-110 Bq kg (81 ± 18 Bq kg), respectively; and K specific activities from 177 to 928 Bq kg (569 ± 184 Bq kg) and 87-303 Bq kg (171 ± 69 Bq kg), respectively. Gypsum samples had U, Th, and K specific activities approximately one order of magnitude less than measured for fly ash samples.

  3. Analysis of Combustion Process of Sewage Sludge in Reference to Coals and Biomass

    Science.gov (United States)

    Środa, Katarzyna; Kijo-Kleczkowska, Agnieszka

    2016-06-01

    Production of sewage sludge is an inseparable part of the treatment process. The chemical and sanitary composition of sewage sludge flowing into the treatment plant is a very important factor determining the further use of the final product obtained in these plants. The sewage sludge is characterized by heterogeneity and multi-components properties, because they have characteristics of the classical and fertilizer wastes and energetic fuels. The thermal utilization of sewage sludge is necessary due to the unfavorable sanitary characteristics and the addition of the industrial sewage. This method ensures use of sewage sludge energy and return of expenditure incurred for the treatment of these wastes and their disposal. Sewage sludge should be analyzed in relation to conventional fuels (coals and biomass). They must comply with the applicable requirements, for example by an appropriate degree of dehydration, which guarantee the stable and efficient combustion. This paper takes the issue of the combustion process of the different sewage sludge and their comparison of the coal and biomass fuels.

  4. [Experimental study on the size spectra and emission factor of ultrafine particle from coal combustion].

    Science.gov (United States)

    Sun, Zai; Yang, Wen-jun; Xie, Xiao-fang; Chen, Qiu-fang; Cai, Zhi-liang

    2014-12-01

    The emission characteristics of ultrafine particles released from pulverized coal combustion were studied, the size spectra of ultrafine particles (5.6-560 nm) were measured with FMPS (fast mobility particle sizer) on a self-built aerosol experiment platform. Meanwhile, a particle dynamic evolution model was established to obtain the particle deposition rate and the emission rate through the optimized algorithm. Finally, the emission factor was calculated. The results showed that at the beginning of particle generation, the size spectra were polydisperse and complex, the initial size spectra was mainly composed of three modes including 10 nm, 30-40 nm and 100-200 nm. Among them, the number concentration of mode around 10 nm was higher than those of other modes, the size spectrum of around 100-200 nm was lognormal distributed, with a CMD (count median diameter) of around 16 nm. Then, as time went on, the total number concentration was decayed by exponential law, the CMD first increased and then tended to be stable gradually. The calculation results showed that the emission factor of particles from coal combustion under laboratory condition was (5.54 x 10(12) ± 2.18 x 10(12)) unit x g(-1).

  5. Size distributions of major elements in residual ash particles from coal combustion

    Institute of Scientific and Technical Information of China (English)

    YU DunXi; XU MingHou; YAO Hong; LIU XiaoWei

    2009-01-01

    Combustion experiments for three coals of different ranks were conducted in an electrically-heated drop tube furnace. The size distributions of major elements in the residual ash particles (>0.4μm) such as AI, Si, S, P, Na, Mg, K, Ca and Fe were investigated. The experimental results showed that the concentrations of AI and Si in the residual ash particles decreased with decreasing particle size, while the concentrations of S and P increased with decreasing particle size. No consistent size distributions were obtained for Na, Mg, K, Ca and Fe. The established deposition model accounting for trace element distributions was demonstrated to be applicable to some major elements as well. The modeling results indicated that the size distributions of the refractory elements, AI and Si, were mainly influenced by the deposition of vaporized elements on particle surfaces. A dominant fraction of S and P vaporized during coal combustion. Their size distributions were determined by surface condensation, reaction or adsorption. The partitioning mechanisms of Na, Mg, K, Ca and Fe were more complex.

  6. Chemical analysis of soil and leachate from experimental wetland mesocosms lined with coal combustion products

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, C.; Mitsch, W.J. [Ohio State University, Columbus, OH (USA). Environmental Science Graduate Program and School of Natural Resources

    2001-08-01

    Small-scale (1 m{sup 2}) wetland mesocosm experiments were conducted over two consecutive growing seasons to investigate the effects on soil and leachate chemistry of using a recycled coal combustion product as a liner. The coal combustion product used as a liner consisted of flue gas desulfurization (FGD) by-products and fly ash. This paper provides the chemical characteristics of mesocosm soil and leachate after 2 yr of experimentation. Arsenic, Ca and pH were higher in FGD-lined mesocosm surface soil relative to unlined mesocosms. Aluminium was higher in the soils of unlined mesocosms relative to FGD-lined mesocosms. No significant difference of potentially phytotoxic B was observed between lined and unlined mesocosms in the soil. Higher pH, conductivity and concentrations of Al, B, Ca, K and S (SO{sub 4}-S) were observed in leachate from lined mesocosms compared with unlined controls while Fe, Mg and Mn were higher in leachate from unlined mesocosms. Concentrations of most elements analyzed in the leachate were below national primary and secondary drinking water standards after 2 yr of experimentation. Initially high pH and soluble salt concentrations measured in the leachate from the lined mesocosms may indicate the reason for early effects noted on the development of wetland vegetation in the mesocosms. 32 refs., 2 figs., 3 tabs.

  7. Use of coal combustion by-products for solidification/stabilization of hazardous wastes

    Energy Technology Data Exchange (ETDEWEB)

    Hassett, D.J.; Pflughoeft-Hassett, D.F.

    1997-05-01

    Five low-rank coal combustion fly ash samples extensively characterized in previous projects were used as a pool of candidate materials for potential use as waste stabilization agents. Two of these fly ash samples were selected because ettringite formed in the solid in long-term leaching experiments, and an associated reduction in leachate concentration of at least one trace element was noted for each sample. The stabilization experiments were designed to evaluate the removal of relatively high concentrations of boron and selenium from a simulated wastewater. Sulfate was added as one variable in order to determine if high concentrations of sulfate would impact the ability of the ettringite to include trace elements in its structure. The following conclusions can be drawn from the information obtained in this research: CCBs (coal combustion by-products) can be useful in the chemical fixation of potentially hazardous trace elements; indication of ettringite formation alone is not adequate for selecting a CCB for waste stabilization applications; moderate sulfate concentrations do not promote or inhibit trace element sorption; ettringite formation mechanisms may impact trace element fixation and need to be elucidated; laboratory demonstration of the CCB with the stabilization process being proposed is necessary to verify the efficacy of the material and process; and the final waste form must be evaluated prior to management according to the required regulatory procedures.

  8. Experimental study on cement clinker co-generation in pulverized coal combustion boilers of power plants.

    Science.gov (United States)

    Wang, Wenlong; Luo, Zhongyang; Shi, Zhenglun; Cen, Kefa

    2006-06-01

    The idea to co-generate cement clinker in pulverized coal combustion (PCC) boilers of power plants is introduced and discussed. An experimental study and theoretical analysis showed this idea to be feasible and promising. By adding quick lime as well as other mineralizers to the coal and grinding the mixture before combustion, sulfoaluminate cement clinker with a high content of silicate (SCCHS) could be generated. The main mineral phases in SCCHS are 2CaO x SiO2 (dicalcium-silicate), 3CaO x 3Al2O3 x CaSO4 (calcium-sulfoaluminate) and 2CaO x A12O3 SiO2 (gehlenite). Performance tests showed that the SCCHS met the requirements for utilization in common construction. Based on this idea, zero solid waste generation from PCC would be realized. Furthermore, thermal power production and cement production could be combined, and this would have a significant effect on both environmental protection and natural resource saving.

  9. Deposit formation during coal-straw co-combustion in a utility PF-boiler

    Energy Technology Data Exchange (ETDEWEB)

    Hedebo Andersen, K.

    1998-08-01

    This work was based on experimental results from a two-year, full scale demonstration programme at the Strudstrup Power Station, Unit 1 (MKS1), owned by Midtkraft Energy Company. Primarily the results from the deposition trials, but also related experimental data, were used in the evaluation. Based upon the visual analyses of the upstream deposits it was found that the deposit amount and tenacity increased with increased exposure time, increased straw share, increased flue gas temperature and increased load (part to full load) during experiments with COCERR coal. The downstream deposits were in all cases powdery deposits, which could easily be removed. When utilising USILI2 coal with higher content of Fe and S than COCERR, the main effect was observed for coal combustion, where both deposit amount and tenacity increased compared to COCERR. From these results, the formation of possibly problematic upstream fouling deposits during coal-straw co-combustion is expected to occur primarily in the first pass. Based on the SEM analyses, the upstream probe deposits collected from the two hottest measuring positions were found to show different structural characteristics at 0 and 20% straw share. Without straw addition, a porous deposit with Fe-based fingerformation with a well-defined structural build-up was formed. At 20% straw share, a porous deposit without Fe-based fingerformation was formed, where large and small particles were deposited in a more random manner. No significant effect could be found in the deposition probe samples for an increase in probe metal temperature from 540 deg. C to 620 deg. C. The importance of deposit shedding was recognised from the experimental data, particularly for the upstream deposits at high flue gas temperatures, 20% straw share and 100% load. The probe deposits were in all cases smaller than those collected from the superheaters during outages after co-combustion at 10 and 20% straw share. However, at 10% straw share, the probe

  10. Air Pollution Assessment Combusting Fermented Waste

    Directory of Open Access Journals (Sweden)

    Violeta Čepanko

    2011-04-01

    Full Text Available This work examines the problem of air pollution burning organic waste from agricultural and drinks production sectors. Chicken and pig manure and biogas dregs after extraction, i.e. after the process of fermentation in laboratory bioreactors were selected as an object of research. The article presents the method of fermented waste incineration and the experimental results of waste incineration. Periodic surveys of kiln load disclosed that under combustion, pollutant concentrations change over time depending on the stage of combustion.Article in Lithuanian

  11. Influence of Coal nature and Structure on Ash Size Formation Characteristic and Related pollutant Emissions During CFB Combustion

    Institute of Scientific and Technical Information of China (English)

    MinQIAN; YongjieNA; 等

    2000-01-01

    The size distribution of coal particles in a Circulating Fluidized Bed(CFB) boiler plays a crucial role in the complicated combustion,heat exchange and pollutant emissions in such a plant.Therefore,it is fundamental to study the different factors having influence on the size distribution of coal particles.Above all,the coal itself and in particular,the coal comminution phenomenon is a very influent factor.In the frame of this work,the coal nature (eleentary compostion) and coal internal structure (mineral componeents) are studied in detail.At this intermediary stage,experients on three typical Chinese coals on a 1.5 MWt CFBC pilot plant have been made.Some primary fragmentation test hae also been made in a small lab scale fluidized bed reactor.The resutls from the hot pilot test show i)the variation of coal ash distributions and other CFB performance data due to the cyclone and the coal characteristics and ii) the variation of desulfurization efficiency with limestone.Whereas the bench scale primary fragmentation test,likely linked to the caking propriety of a coal,does not seem to change considerable the char size distribution.

  12. Trace element emissions from spontaneous combustion of gob piles in coal mines, Shanxi, China

    Science.gov (United States)

    Zhao, Y.; Zhang, Jiahua; Chou, C.-L.; Li, Y.; Wang, Z.; Ge, Y.; Zheng, C.

    2008-01-01

    The emissions of potentially hazardous trace elements from spontaneous combustion of gob piles from coal mining in Shanxi Province, China, have been studied. More than ninety samples of solid waste from gob piles in Shanxi were collected and the contents of twenty potentially hazardous trace elements (Be, F, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sn, Sb, Hg, Tl, Pb, Th, and U) in these samples were determined. Trace element contents in solid waste samples showed wide ranges. As compared with the upper continental crust, the solid waste samples are significantly enriched in Se (20x) and Tl (12x) and are moderately enriched in F, As, Mo, Sn, Sb, Hg, Th, and U (2-5x). The solid waste samples are depleted in V, Cr, Mn, Co, Ni, Cu, and Zn. The solid waste samples are enriched in F, V, Mn, Cr, Co, Ni, Cu, Zn, Sb, Th, and U as compared with the Shanxi coals. Most trace elements are higher in the clinker than in the unburnt solid waste except F, Sn, and Hg. Trace element abundances are related to the ash content and composition of the samples. The content of F is negatively correlated with the ash content, while Pb is positively correlated with the ash. The concentrations of As, Mn, Zn, and Cd are highly positively correlated with Fe2O3 in the solid waste. The As content increases with increasing sulfur content in the solid waste. The trace element emissions are calculated for mass balance. The emission factors of trace elements during the spontaneous combustion of the gobs are determined and the trace element concentrations in the flue gas from the spontaneous combustion of solid waste are calculated. More than a half of F, Se, Hg and Pb are released to the atmosphere during spontaneous combustion. Some trace element concentrations in flue gas are higher than the national emission standards. Thus, gob piles from coal mining pose a serious environmental problem. ?? 2007 Elsevier B.V. All rights reserved.

  13. Zinc Isotope Variability in Three Coal-Fired Power Plants: A Predictive Model for Determining Isotopic Fractionation during Combustion.

    Science.gov (United States)

    Ochoa Gonzalez, R; Weiss, D

    2015-10-20

    The zinc (Zn) isotope compositions of feed materials and combustion byproducts were investigated in three different coal-fired power plants, and the results were used to develop a generalized model that can account for Zn isotopic fractionation during coal combustion. The isotope signatures in the coal (δ(66)ZnIRMM) ranged between +0.73 and +1.18‰, values that fall well within those previously determined for peat (+0.6 ±2.0‰). We therefore propose that the speciation of Zn in peat determines the isotope fingerprint in coal. All of the bottom ashes collected in these power plants were isotopically depleted in the heavy isotopes relative to the coals, with δ(66)ZnIRMM values ranging between +0.26‰ and +0.64‰. This suggests that the heavy isotopes, possibly associated with the organic matter of the coal, may be preferentially released into the vapor phase. The fly ash in all of these power plants was, in contrast, enriched in the heavy isotopes relative to coal. The signatures in the fly ash can be accounted for using a simple unidirectional fractionation model with isotope fractionation factors (αsolid-vapor) ranging between 1.0003 and 1.0007, and we suggest that condensation is the controlling process. The model proposed allows, once the isotope composition of the feed coal is known, the constraining of the Zn signatures in the byproducts. This will now enable the integration of Zn isotopes as a quantitative tool for the source apportionment of this metal from coal combustion in the atmosphere.

  14. The Cellular Toxicity of PM2.5 Emitted from Coal Combustion in Human Umbilical Vein Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    WANGFeiFei; GENGChunMei; HAO WeiDong; ZHAO YongDong; LIQin; WANG HongMei; QIAN Yan

    2016-01-01

    ObjectiveTo explore the relationship between different components offineparticulate matter (PM2.5) emitted from coal combustion and their cytotoxic effect in the vascular endothelial cells. MethodsCoal-fired PM2.5was sampled using a fixed-source dilution channel and flow sampler. The sample components were analyzed by ion chromatography and inductively coupled plasma atomic emission spectroscopy(ICP-AES). The PM2.5suspension was extracted using an ultrasonic water-bath method and thenhuman umbilical vein endothelial cells (EA.hy926) were treated withvarious concentrations of the PM2.5 suspension. Cell proliferation,oxidativeDNA damage, and global DNA methylation levelswere used to measurethe cellulartoxicity of PM2.5emitted fromcoalcombustion. ResultsComparedtoothertypesof coal-fired PM2.5preparations,thePM2.5 suspension from Yinchuan coal had the highest cytotoxicity.PM2.5 suspension from Datong coal hadthe highest toxic effectwhile that fromYinchuan coal had the lowest.Exposure to coal-fired PM2.5 from Jingxi coalresulted inlower 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. At the same dose, PM2.5 emitted from coal combustion could produce more severeDNAimpairmentcompared to that produced by carbon black.Cell survival rate was negatively correlated with chloride and potassiumionscontent.The5-methylcytosine(5-mC) level waspositively correlated withMnandnegatively correlated withZn levels.The 8-OHdG% level was positively correlated withboth MnandFe. ConclusionPM2.5 emitted from coal combustion can decrease cell viability, increase global DNA methylation, and causeoxidativeDNA damage inEA.hy926 cells. Metalcomponentsmay be important factors that influence cellular toxicity.

  15. 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

  16. Emission characteristics of co-combustion of sewage sludge with olive cake and lignite coal in a circulating fluidized bed.

    Science.gov (United States)

    Toraman, Oner Yusuf; Topal, Hüseyin; Bayat, Oktay; Atimtay, Aysel T

    2004-01-01

    In this study, a circulating fluidized bed (CFB) of 125 mm diameter and 1800mm height was used to find the combustion characteristics of sewage sludge (SS) produced in Turkey. Sludge + olive cake, and sludge + lignite coal mixtures were burned separately. Various sludge-to-lignite coal and sludge-to-olive cake ratios (5/95, 10/90, 15/85, 20/80) were tried. On-line concentrations of major components (O2, SO2, CO2, CO, NOx, CmHn) were measured in the flue gas, as well as temperature and pressure distributions along the bed. Combustion efficiencies of sludge + olive cake and sludge + lignite coal mixtures were calculated, and the optimum conditions for operating parameters were discussed. The results have shown that the combustion mainly takes place in the upper regions of the main column where the temperature reaches 900 degrees C. SS + Coal burn in the CFB with an efficiency of 95.14% to 96.18%, which is considered to be quite good. When burning sludge mixed with olive cake, appreciable amounts of CO and unburned hydrocarbons are formed and the combustion efficiency drops to 92.93%. CO and CmHn emissions are lower when lignite coal is mixed with various amounts of SS than the emissions when the coal is burned alone. As the %SS is increased in the fuel mixture, the SO2 emission decreases. NOx emissions are slightly higher. When burning sludge mixed with olive cake, SO2 and NOx emissions are slightly higher. CO and CmHn emissions decrease sharply when SS is mixed with 5%wt. olive cake. With increasing sludge ratio these emissions increase due to the unburned hydrocarbons. As a result of this study, it is believed that SS can be burned effectively in a CFBC together with other fuels, especially with olive cake (OC). OC will be a good additive fuel for the combustion of lower quality fuels.

  17. Experimental analysis of a combustion reactor under co-firing coal with biomass

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Fabyo Luiz; Bazzo, Edson; Oliveira Junior, Amir Antonio Martins de [Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil). LabCET], e-mail: ebazzo@emc.ufsc.br; Bzuneck, Marcelo [Tractebel Energia S.A., Complexo Termeletrico Jorge Lacerda, Capivari de Baixo, SC (Brazil)], e-mail: marcelob@tractebelenergia.com.br

    2010-07-01

    Mitigation of greenhouse gases emission is one of the most important issues in energy engineering. Biomass is a potential renewable source but with limited use in large scale energy production because of the relative smaller availability as compared to fossil fuels, mainly to coal. Besides, the costs concerning transportation must be well analysed to determine its economic viability. An alternative for the use of biomass as a primary source of energy is the co-firing, that is the possibility of using two or more types of fuels combined in the combustion process. Biomass can be co-fired with coal in a fraction between 10 to 25% in mass basis (or 4 to 10% in heat-input basis) without seriously impacting the heat release characteristics of most boilers. Another advantage of cofiring, besides the significant reductions in fossil CO{sub 2} emissions, is the reduced emissions of NO{sub x} and SO{sub x}. As a result, co-firing is becoming attractive for power companies worldwide. This paper presents results of some experimental analysis on co-firing coal with rice straw in a combustion reactor. The influence of biomass thermal share in ash composition is also discussed, showing that alkali and earth alkaline compounds play the most important role on the fouling and slagging behavior when co-firing. Some fusibility correlations that can assist in the elucidation of these behavior are presented and discussed, and then applied to the present study. Results show that for a biomass thermal share up to 20%, significant changes are not expected in fouling and slagging behavior of ash. (author)

  18. Influence of mineral transformation on emission of particulate matters during coal combustion

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaowei; XU Minghou; YU Dunxi; GAO Xiangpeng; CAO Qian; HAO Wei

    2007-01-01

    Combustion of pulverized coal was studied in a drop tube furnace to understand coal mineral properties with the emission of particulate matters (PM). Experimental conditions were selected as follows: coal particle size was smaller than 63 μm; reaction temperature was 1 100℃, 1 250℃ and 1 400℃ respectively; oxygen content was 20% and 50% respectively, PM was collected with a 13-stagelow pressure impactor (LPI) having an aerodynamic cut-off diameter ranging from 10.0 μm to 0.03 μm for a size-segregated collection. Such properties as concentration, particle size distribution and elemental composition of PM were investigated. The experimental results indicate that the emitted PM has a bimodal distribution having two peaks around 4.0 μm and 0.1 μm Increasing temperature leads to the formation of more PM; varied oxygen content leads to much change of emitted PM. PM was also subjected to XRF analysis to quantify the elemental composition. The results show that PM of 0.1 μm is rich in sulfates. Meanwhile, SiO2 and Al2O3 are prevalent in PM of 4.0 μm, which means that the last peak around 4.0 μm is mainly aluminosilicate salts.

  19. Selenium Ecotoxicology in Freshwater Lakes Receiving Coal Combustion Residual Effluents: A North Carolina Example.

    Science.gov (United States)

    Brandt, Jessica E; Bernhardt, Emily S; Dwyer, Gary S; Di Giulio, Richard T

    2017-02-21

    Anthropogenic activities resulting in releases of selenium-laden waste streams threaten freshwater ecosystems. Lake ecosystems demand special consideration because they are characterized by prolonged retention of selenium and continuous cycling of the element through the food chain, through which it becomes available to toxicologically susceptible egg-laying vertebrates. This study documents the current selenium burden of lakes in North Carolina (NC) with historic selenium inputs from nearby coal-fired power plants. We measured selenium concentrations in surface waters, sediment pore waters, and resident fish species from coal combustion residual (CCR)-impacted lakes and paired reference lakes. The data are related to levels of recent selenium inputs and analyzed in the context of recently updated federal criteria for the protection of aquatic life. We show that the Se content of fish from lakes with the highest selenium inputs regularly exceed these criteria and are comparable to those measured during historic fish extirpation events in the United States. Large legacy depositions of CCRs within reservoir sediments are likely to sustain Se toxicity for many years despite recent laws to limit CCR discharge into surface waters in NC. Importantly, the widespread use of high-selenium coals for electricity generation extends the potential risk for aquatic ecosystem impacts beyond U.S. borders.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-04-29

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

  1. Environmental investigation on co-combustion of sewage sludge and coal gangue: SO2, NOx and trace elements emissions.

    Science.gov (United States)

    Yang, Zhenzhou; Zhang, Yingyi; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2016-04-01

    To promote the utilization of waste material as alternative fuel, the mono- and co-combustion characteristics of sewage sludge (SS) and coal gangue (CG) were systematically investigated, with emphasis on environmental influences. The emission of SO2, NOx as well as the trace elements during combustion of SS and CG were studied with regard to the effects of their chemistries, structures and interactions. Results showed that co-combustion can be beneficial for ignition performance. A synergic effect on both desulfurization and denitrification can be expected at ca. 800°C. Further, an enhanced retention of trace elements during co-combustion was also observed, especially for Pb and Zn. On the basis of the results, it can be expected that, with proper operation, co-combustion of SS and CG can be a promising method for the disposal of these two wastes.

  2. CHARACTERIZATION OF MERCURY-ENRICHED COAL COMBUSTION RESIDUES FROM ELECTRIC UTILITIES USING ENHANCED SORBENTS FOR MERCURY CONTROL

    Science.gov (United States)

    Leaching of mercury and other constituents of potential concern during land disposal or beneficial use of coal combustion residues (CCRs) is the environmental impact pathway evaluated in this report. The specific objectives of the research was to: (1) evaluate mercury, arsenic an...

  3. Dry sorbent injection of trona to control acid gases from a pilot-scale coal-fired combustion facility

    Science.gov (United States)

    Gaseous and particulate emissions from the combustion of coal have been associated with adverse effects on human and environmental health, and have for that reason been subject to regulation by federal and state governments. Recent regulations by the United States Environmental ...

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

    Science.gov (United States)

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

  5. MERCURY OXIDATION PROMOTED BY A SELECTIVE CATALYTIC REDUCTION CATALYST UNDER SIMULATED POWDER RIVER BASIN COAL COMBUSTION CONDITIONS

    Science.gov (United States)

    A bench-scale reactor consisting of a natural gas burner and an electrically heated reactor housing a selective catalytic reduction (SCR) catalyst was constructed for studying elemental mercury oxidation under SCR conditions. A low sulfur Power River Basin (PRB) coal combustion ...

  6. Coal combustion waste management at landfills and surface impoundments 1994-2004.

    Energy Technology Data Exchange (ETDEWEB)

    Elcock, D.; Ranek, N. L.; Environmental Science Division

    2006-09-08

    On May 22, 2000, as required by Congress in its 1980 Amendments to the Resource Conservation and Recovery Act (RCRA), the U.S. Environmental Protection Agency (EPA) issued a Regulatory Determination on Wastes from the Combustion of Fossil Fuels. On the basis of information contained in its 1999 Report to Congress: Wastes from the Combustion of Fossil Fuels, the EPA concluded that coal combustion wastes (CCWs), also known as coal combustion by-products (CCBs), did not warrant regulation under Subtitle C of RCRA, and it retained the existing hazardous waste exemption for these materials under RCRA Section 3001(b)(3)(C). However, the EPA also determined that national regulations under Subtitle D of RCRA were warranted for CCWs that are disposed of in landfills or surface impoundments. The EPA made this determination in part on the basis of its findings that 'present disposal practices are such that, in 1995, these wastes were being managed in 40 percent to 70 percent of landfills and surface impoundments without reasonable controls in place, particularly in the area of groundwater monitoring; and while there have been substantive improvements in state regulatory programs, we have also identified gaps in State oversight' (EPA 2000). The 1999 Report to Congress (RTC), however, may not have reflected the changes in CCW disposal practices that occurred since the cutoff date (1995) of its database and subsequent developments. The U.S. Department of Energy (DOE) and the EPA discussed this issue and decided to conduct a joint DOE/EPA study to collect new information on the recent CCW management practices by the power industry. It was agreed that such information would provide a perspective on the chronological adoption of control measures in CCW units based on State regulations. A team of experts from the EPA, industry, and DOE (with support from Argonne National Laboratory) was established to develop a mutually acceptable approach for collecting and analyzing data

  7. CFD investigation on the flow and combustion in a 300 MWe tangentially fired pulverized-coal furnace

    Science.gov (United States)

    Khaldi, Nawel; Chouari, Yoldoss; Mhiri, Hatem; Bournot, Philippe

    2016-09-01

    The characteristics of the flow, combustion and temperature in a 300 MWe tangentially fired pulverized-coal furnace are numerically studied using computational fluid dynamics. The mathematical model is based on a Eulerian description for the continuum phase and a Lagrangian description for coal particles. The combustion reaction scheme was modeled using eddy dissipation concept. The application of a proper turbulence model is mandatory to generate accurate predictions of flow and heat transfer during combustion. The current work presents a comparative study to identify the suitable turbulence model for tangentially fired furnace problem. Three turbulence models including the standard k-ɛ model, the RNG k-ɛ model and the Reynolds Stress model, RSM are examined. The predictions are compared with the published experimental data of Zheng et al. (Proc Combust Inst 29: 811-818, 2002). The RNG k-ɛ model proves to be the most suitable turbulence model, offering a satisfactory prediction of the velocity, temperature and species fields. The detailed results presented in this paper may enhance the understanding of complex flow patterns and combustion processes in tangentially fired pulverized-coal furnaces.

  8. Characterization of single coal particle combustion within oxygen-enriched environments using high-speed OH-PLIF

    Science.gov (United States)

    Köser, J.; Becker, L. G.; Vorobiev, N.; Schiemann, M.; Scherer, V.; Böhm, B.; Dreizler, A.

    2015-12-01

    This work presents first-of-its-kind high-speed planar laser-induced fluorescence measurements of the hydroxyl radical in the boundary layer of single coal particles. Experiments were performed in a laminar flow reactor providing an oxygen-enriched exhaust gas environment at elevated temperatures. Single coal particles in a sieve fraction of 90-125 µm and a significant amount of volatiles (36 wt%) were injected along the burner's centerline. Coherent anti-Stokes Raman spectroscopy measurements were taken to characterize the gas-phase temperature. Time-resolved imaging of the OH distribution at 10 kHz allowed identifying reaction and post-flame zones and gave access to the temporal evolution of burning coal particles. During volatile combustion, a symmetric diffusion flame was observed around the particle starting from a distance of ~150 µm from the particle surface. For subsequent char combustion, this distance decreased and the highest OH signals appeared close to the particle surface.

  9. Simulation on Different Proportions of Coal and Natural Gas Co-combustion in a Rotary Lime Kiln

    Directory of Open Access Journals (Sweden)

    Hongyu Gu

    2011-06-01

    Full Text Available Co-combustion of coal and natural gas is a promising technology in the production of active lime. For this technology, proper fuel proportion of coal and natural gas (α is one of the key parameters that requires significant thought. By means of numerical simulation, contrast studies on co-combustion with five different fuel proportions were carried out. This paper firstly puts forward the models used to describe the system based on the actual conditions. Then, numerical simulation results were analysed in detail to illustrate the co-combustion process and the velocity and temperature distribution in the kiln. Finally, comparisons of high temperature region, char conversion, length of calcining zone, CO and NOx emission and total heat transfer rate to the material bed were made in order to make a decision on fuel proportion. Synthetically considering, α=30% is a balance between benefits and costs for the rotary lime kiln studied.

  10. Pilot Testing of WRI'S Novel Mercury Control Technology by Pre-Combustion Thermal Treatment of Coal

    Energy Technology Data Exchange (ETDEWEB)

    Alan Bland; Jesse Newcomer; Kumar Sellakumar

    2008-08-17

    The challenges to the coal-fired power industry continue to focus on the emission control technologies, such as mercury, and plant efficiency improvements. An alternate approach to post-combustion control of mercury, while improving plant efficiency deals with Western Research Institute's (WRI)'s patented pre-combustion mercury removal and coal upgrading technology. WRI was awarded under the DOE's Phase III Mercury program, to evaluate the effectiveness of WRI's novel thermal pretreatment process to achieve >50% mercury removal, and at costs of <$30,000/lb of Hg removed. WRI has teamed with Etaa Energy, Energy and Environmental Research Center (EERC), Foster Wheeler North America Corp. (FWNA), and Washington Division of URS (WD-URS), and with project co-sponsors including Electric Power Research Institute (EPRI), Southern Company, Basin Electric Power Cooperative (BEPC), Montana-Dakota Utilities (MDU), North Dakota Industrial Commission (NDIC), Detroit Edison (DTE), and SaskPower to undertake this evaluation. The technical objectives of the project were structured in two phases: Phase I--coal selection and characterization, and bench-and PDU-scale WRI process testing and; and Phase II--pilot-scale pc combustion testing, design of an integrated boiler commercial configuration, its impacts on the boiler performance and the economics of the technology related to market applications. This report covers the results of the Phase I testing. The conclusion of the Phase I testing was that the WRI process is a technically viable technology for (1) removing essentially all of the moisture from low rank coals, thereby raising the heating value of the coal by about 30% for subbituminous coals and up to 40% for lignite coals, and (2) for removing volatile trace mercury species (up to 89%) from the coal prior to combustion. The results established that the process meets the goals of DOE of removing <50% of the mercury from the coals by pre-combustion methods

  11. Quality and Environmental Impact Assessment of Coal Deposits of Punjab Pakistan

    Directory of Open Access Journals (Sweden)

    *1S. Imad

    2014-12-01

    Full Text Available Major coal fields in Punjab Province are located in t