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P A Strizhak - One of the best experts on this subject based on the ideXlab platform.
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major gas emissions from combustion of slurry fuels based on Coal Coal waste and Coal derivatives
Journal of Cleaner Production, 2018Co-Authors: Margarita A Dmitrienko, Galina S Nyashina, P A StrizhakAbstract:Abstract This research experimentally determines the major gas emissions from the industrial combustion of Coal, Coal Processing waste, and Coal derivatives in the form of traditional Coal dust as well as slurry fuels with water and flammable additives. Several types of Coal are considered: gas Coal, flame Coal, bituminous, non-coking and low-caking Coal, as well as Coal Processing waste (filter cakes), Coal derivatives (coke, semi-coke), and flammable liquids (industrial oil waste, fuel oil). Experimental data for charCoal and carbon dust from recycled car tires are presented as well. The concentration is evaluated for the most hazardous gas emissions: sulfur and nitrogen oxides. A number of factors defining the said concentrations are established: the quality of components, their elemental composition and concentration (40–60% Coal, 30–50% water, 5–15% flammable liquid); slurry preparation method (homogenizer or cavitator); Coal grind (8–250 μm); and the mass of the batch (0.5–1.5 g). In particular, changing Coal concentration in a slurry from 40 to 60% increases the emission of nitrogen oxide by 35% and sulfur oxide by 67%. Varying water concentration from 30 to 50% decreases the emission of nitrogen oxide by 17% and sulfur oxide by 62%. Increasing the flammable liquid concentration from 5 to 15% slightly lowers the emission of nitrogen oxide (by 5%), while the sulfur oxide emission grows by 28%. The advantages of Coal-water slurry containing petrochemicals combustion are identified over Coal. Moreover, the main limitations are determined for large-scale usage of slurry fuels instead of traditional heat and power industry fuels.
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Coal water slurries containing petrochemicals to solve problems of air pollution by Coal thermal power stations and boiler plants an introductory review
Science of The Total Environment, 2018Co-Authors: Margarita A Dmitrienko, P A StrizhakAbstract:Abstract This introductory study presents the analysis of the environmental, economic and energy performance indicators of burning high-potential Coal water slurries containing petrochemicals (CWSP) instead of Coal, fuel oil, and natural gas at typical thermal power stations (TPS) and a boiler plant. We focus on the most hazardous anthropogenic emissions of Coal power industry: sulfur and nitrogen oxides. The research findings show that these emissions may be several times lower if Coal and oil Processing wastes are mixed with water as compared to the combustion of traditional pulverized Coal, even of high grades. The study focuses on wastes, such as filter cakes, oil sludge, waste industrial oils, heavy Coal-tar products, resins, etc., that are produced and stored in abundance. Their deep conversion is very rare due to low economic benefit. Effective ways are necessary to recover such industrial wastes. We present the cost assessment of the changes to the heat and power generation technologies that are required from typical power plants for switching from Coal, fuel oil and natural gas to CWSPs based on Coal and oil Processing wastes. The corresponding technological changes pay off after a short time, ranging from several months to several years. The most promising components for CWSP production have been identified, which provide payback within a year. Among these are filter cakes (Coal Processing wastes), which are produced as a ready-made Coal-water slurry fuel (a mixture of flocculants, water, and fine Coal dust). These fuels have the least impact on the environment in terms of the emissions of sulfur and nitrogen oxides as well as fly ash. An important conclusion of the study is that using CWSPs based on filter cakes is worthwhile both as the main fuel for thermal power stations and boiler plants and as starting fuel.
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experimental evaluation of main emissions during Coal Processing waste combustion
Environmental Pollution, 2018Co-Authors: Margarita A Dmitrienko, Jean Claude Legros, P A StrizhakAbstract:Abstract The total volume of the Coal Processing wastes (filter cakes) produced by Russia, China, and India is as high as dozens of millions of tons per year. The concentrations of CO and CO2 in the emissions from the combustion of filter cakes have been measured directly for the first time. They are the biggest volume of Coal Processing wastes. There have been many discussions about using these wastes as primary or secondary components of Coal-water slurries (CWS) and Coal-water slurries containing petrochemicals (CWSP). Boilers have already been operationally tested in Russia for the combustion of CWSP based on filter cakes. In this work, the concentrations of hazardous emissions have been measured at temperatures ranging from 500 to 1000°С. The produced CO and CO2 concentrations are shown to be practically constant at high temperatures (over 900°С) for all the Coal Processing wastes under study. Experiments have shown the feasibility to lowering the combustion temperatures of Coal Processing wastes down to 750–850°С. This provides sustainable combustion and reduces the CO and CO2 emissions 1.2–1.7 times. These relatively low temperatures ensure satisfactory environmental and energy performance of combustion. Using CWS and CWSP instead of conventional solid fuels significantly reduces NOx and SOx emissions but leaves CO and CO2 emissions practically at the same level as Coal powder combustion. Therefore, the environmentally friendly future (in terms of all the main atmospheric emissions: CO, CO2, NOx, and SOx) of both CWS and CWSP technologies relies on low-temperature combustion.
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environmentally and economically efficient utilization of Coal Processing waste
Science of The Total Environment, 2017Co-Authors: Margarita A Dmitrienko, P A StrizhakAbstract:Abstract High concentrations of hazardous anthropogenic emissions (sulfur, nitrogen and carbon oxides) from solid fuel combustion in Coal burning plants cause environmental problems that have been especially pressing over the last 20–30 years. A promising solution to these problems is a switch from conventional pulverized Coal combustion to Coal-water slurry fuel. In this paper, we pay special attention to the environmental indicators characterizing the combustion of different Coal ranks (gas, flame, coking, low-caking, and nonbaking Coals) and Coal-water slurry fuels based on the Coal Processing waste – filter cakes. There have been no consistent data so far on the acceptable intervals for the anthropogenic emissions of sulfur (SO x ), nitrogen (NO x ) and carbon (CO, CO 2 ) oxides. Using a specialized combustion chamber and gas analyzing system, we have measured the concentrations of typical Coal and filter-cake-based CWS combustion products. We have also calculated the typical combustion heat of the fuels under study and measured the ratio between environmental and energy attributes. The research findings show that the use of filter cakes in the form of CWS is even better than Coals in terms of environment and economy. Wide utilization of filter cakes solves many environmental problems: the areas of contaminated sites shrink, anthropogenic emissions decrease, and there is no need to develop new Coal mines anymore.
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environmental indicators of the combustion of prospective Coal water slurry containing petrochemicals
Journal of Hazardous Materials, 2017Co-Authors: Margarita A Dmitrienko, Galina S Nyashina, P A StrizhakAbstract:Negative environmental impact of Coal combustion has been known to humankind for a fairly long time. Sulfur and nitrogen oxides are considered the most dangerous anthropogenic emissions. A possible solution to this problem is replacing Coal dust combustion with that of Coal water slurry containing petrochemicals (CWSP). Coal Processing wastes and used combustible liquids (oils, sludge, resins) are promising in terms of their economic and energy yield characteristics. However, no research has yet been conducted on the environmental indicators of fuels based on CWSP. The present work contains the findings of the research of CO, CO2, NOx, SOx emissions from the combustion of Coals and CWSPs produced from Coal Processing waste (filter cakes). It is demonstrated for the first time that the concentrations of dangerous emissions from the combustion of CWSPs (carbon oxide and dioxide), even when combustible heavy liquid fractions are added, are not worse than those of Coal. As for the concentration of sulfur and nitrogen oxides, it is significantly lower for CWSPs combustion as compared to Coals. The presented research findings illustrate the prospects of the wide use of CWSPs as a fuel that is cheap and beneficial, in terms of both energy output and ecology, as compared to Coal.
Margarita A Dmitrienko - One of the best experts on this subject based on the ideXlab platform.
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major gas emissions from combustion of slurry fuels based on Coal Coal waste and Coal derivatives
Journal of Cleaner Production, 2018Co-Authors: Margarita A Dmitrienko, Galina S Nyashina, P A StrizhakAbstract:Abstract This research experimentally determines the major gas emissions from the industrial combustion of Coal, Coal Processing waste, and Coal derivatives in the form of traditional Coal dust as well as slurry fuels with water and flammable additives. Several types of Coal are considered: gas Coal, flame Coal, bituminous, non-coking and low-caking Coal, as well as Coal Processing waste (filter cakes), Coal derivatives (coke, semi-coke), and flammable liquids (industrial oil waste, fuel oil). Experimental data for charCoal and carbon dust from recycled car tires are presented as well. The concentration is evaluated for the most hazardous gas emissions: sulfur and nitrogen oxides. A number of factors defining the said concentrations are established: the quality of components, their elemental composition and concentration (40–60% Coal, 30–50% water, 5–15% flammable liquid); slurry preparation method (homogenizer or cavitator); Coal grind (8–250 μm); and the mass of the batch (0.5–1.5 g). In particular, changing Coal concentration in a slurry from 40 to 60% increases the emission of nitrogen oxide by 35% and sulfur oxide by 67%. Varying water concentration from 30 to 50% decreases the emission of nitrogen oxide by 17% and sulfur oxide by 62%. Increasing the flammable liquid concentration from 5 to 15% slightly lowers the emission of nitrogen oxide (by 5%), while the sulfur oxide emission grows by 28%. The advantages of Coal-water slurry containing petrochemicals combustion are identified over Coal. Moreover, the main limitations are determined for large-scale usage of slurry fuels instead of traditional heat and power industry fuels.
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Coal water slurries containing petrochemicals to solve problems of air pollution by Coal thermal power stations and boiler plants an introductory review
Science of The Total Environment, 2018Co-Authors: Margarita A Dmitrienko, P A StrizhakAbstract:Abstract This introductory study presents the analysis of the environmental, economic and energy performance indicators of burning high-potential Coal water slurries containing petrochemicals (CWSP) instead of Coal, fuel oil, and natural gas at typical thermal power stations (TPS) and a boiler plant. We focus on the most hazardous anthropogenic emissions of Coal power industry: sulfur and nitrogen oxides. The research findings show that these emissions may be several times lower if Coal and oil Processing wastes are mixed with water as compared to the combustion of traditional pulverized Coal, even of high grades. The study focuses on wastes, such as filter cakes, oil sludge, waste industrial oils, heavy Coal-tar products, resins, etc., that are produced and stored in abundance. Their deep conversion is very rare due to low economic benefit. Effective ways are necessary to recover such industrial wastes. We present the cost assessment of the changes to the heat and power generation technologies that are required from typical power plants for switching from Coal, fuel oil and natural gas to CWSPs based on Coal and oil Processing wastes. The corresponding technological changes pay off after a short time, ranging from several months to several years. The most promising components for CWSP production have been identified, which provide payback within a year. Among these are filter cakes (Coal Processing wastes), which are produced as a ready-made Coal-water slurry fuel (a mixture of flocculants, water, and fine Coal dust). These fuels have the least impact on the environment in terms of the emissions of sulfur and nitrogen oxides as well as fly ash. An important conclusion of the study is that using CWSPs based on filter cakes is worthwhile both as the main fuel for thermal power stations and boiler plants and as starting fuel.
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experimental evaluation of main emissions during Coal Processing waste combustion
Environmental Pollution, 2018Co-Authors: Margarita A Dmitrienko, Jean Claude Legros, P A StrizhakAbstract:Abstract The total volume of the Coal Processing wastes (filter cakes) produced by Russia, China, and India is as high as dozens of millions of tons per year. The concentrations of CO and CO2 in the emissions from the combustion of filter cakes have been measured directly for the first time. They are the biggest volume of Coal Processing wastes. There have been many discussions about using these wastes as primary or secondary components of Coal-water slurries (CWS) and Coal-water slurries containing petrochemicals (CWSP). Boilers have already been operationally tested in Russia for the combustion of CWSP based on filter cakes. In this work, the concentrations of hazardous emissions have been measured at temperatures ranging from 500 to 1000°С. The produced CO and CO2 concentrations are shown to be practically constant at high temperatures (over 900°С) for all the Coal Processing wastes under study. Experiments have shown the feasibility to lowering the combustion temperatures of Coal Processing wastes down to 750–850°С. This provides sustainable combustion and reduces the CO and CO2 emissions 1.2–1.7 times. These relatively low temperatures ensure satisfactory environmental and energy performance of combustion. Using CWS and CWSP instead of conventional solid fuels significantly reduces NOx and SOx emissions but leaves CO and CO2 emissions practically at the same level as Coal powder combustion. Therefore, the environmentally friendly future (in terms of all the main atmospheric emissions: CO, CO2, NOx, and SOx) of both CWS and CWSP technologies relies on low-temperature combustion.
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environmentally and economically efficient utilization of Coal Processing waste
Science of The Total Environment, 2017Co-Authors: Margarita A Dmitrienko, P A StrizhakAbstract:Abstract High concentrations of hazardous anthropogenic emissions (sulfur, nitrogen and carbon oxides) from solid fuel combustion in Coal burning plants cause environmental problems that have been especially pressing over the last 20–30 years. A promising solution to these problems is a switch from conventional pulverized Coal combustion to Coal-water slurry fuel. In this paper, we pay special attention to the environmental indicators characterizing the combustion of different Coal ranks (gas, flame, coking, low-caking, and nonbaking Coals) and Coal-water slurry fuels based on the Coal Processing waste – filter cakes. There have been no consistent data so far on the acceptable intervals for the anthropogenic emissions of sulfur (SO x ), nitrogen (NO x ) and carbon (CO, CO 2 ) oxides. Using a specialized combustion chamber and gas analyzing system, we have measured the concentrations of typical Coal and filter-cake-based CWS combustion products. We have also calculated the typical combustion heat of the fuels under study and measured the ratio between environmental and energy attributes. The research findings show that the use of filter cakes in the form of CWS is even better than Coals in terms of environment and economy. Wide utilization of filter cakes solves many environmental problems: the areas of contaminated sites shrink, anthropogenic emissions decrease, and there is no need to develop new Coal mines anymore.
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environmental indicators of the combustion of prospective Coal water slurry containing petrochemicals
Journal of Hazardous Materials, 2017Co-Authors: Margarita A Dmitrienko, Galina S Nyashina, P A StrizhakAbstract:Negative environmental impact of Coal combustion has been known to humankind for a fairly long time. Sulfur and nitrogen oxides are considered the most dangerous anthropogenic emissions. A possible solution to this problem is replacing Coal dust combustion with that of Coal water slurry containing petrochemicals (CWSP). Coal Processing wastes and used combustible liquids (oils, sludge, resins) are promising in terms of their economic and energy yield characteristics. However, no research has yet been conducted on the environmental indicators of fuels based on CWSP. The present work contains the findings of the research of CO, CO2, NOx, SOx emissions from the combustion of Coals and CWSPs produced from Coal Processing waste (filter cakes). It is demonstrated for the first time that the concentrations of dangerous emissions from the combustion of CWSPs (carbon oxide and dioxide), even when combustible heavy liquid fractions are added, are not worse than those of Coal. As for the concentration of sulfur and nitrogen oxides, it is significantly lower for CWSPs combustion as compared to Coals. The presented research findings illustrate the prospects of the wide use of CWSPs as a fuel that is cheap and beneficial, in terms of both energy output and ecology, as compared to Coal.
Li Yuan - One of the best experts on this subject based on the ideXlab platform.
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aerobic and anaerobic microbial degradation of crude 4 methylcyclohexyl methanol in river sediments
Science of The Total Environment, 2016Co-Authors: Li Yuan, Xi Chen, Wei Zhi, Yangsheng Liu, Elizabeth Smiley, Daniel L Gallagher, Andrea M Dietrich, Husen ZhangAbstract:Cyclohexane and some of its derivatives have been a major concern because of their significant adverse human health effects and widespread occurrence in the environment. The 2014 West Virginia chemical spill has raised public attention to (4-methylcyclohexyl)methanol (4-MCHM), one cyclohexane derivative, which is widely used in Coal Processing but largely ignored. In particular, the environmental fate of its primary components, cis- and trans-4-MCHM, remains largely unexplored. This study aimed to investigate the degradation kinetics and mineralization of cis- and trans-4-MCHM by sediment microorganisms under aerobic and anaerobic conditions. We found the removal of cis- and trans-4-MCHM was mainly attributed to biodegradation with little contribution from sorption. A nearly complete aerobic degradation of 4-MCHM occurred within 14 days, whereas the anaerobic degradation was reluctant with residual percentages of 62.6% of cis-4-MCHM and 85.0% of trans-4-MCHM after 16-day incubation. The cis-4-MCHM was degraded faster than the trans under both aerobic and anaerobic conditions, indicating an isomer-specific degradation could occur during the 4-MCHM degradation. Nitrate addition enhanced 4-MCHM mineralization by about 50% under both aerobic and anaerobic conditions. Both cis- and trans-4-MCHM fit well with the first-order kinetic model with respective degradation rates of 0.46-0.52 and 0.19-0.31 day(-)(1) under aerobic condition. Respective degradation rates of 0.041-0.095 and 0.013-0.052 day(-)(1) occurred under anaerobic condition. One bacterial strain capable of effectively degrading 4-MCHM isomers was isolated from river sediments and identified as Bacillus pumilus at the species level based on 16S rRNA gene sequence and 97% identity. Our findings will provide critical information for improving the prediction of the environmental fate of 4-MCHM and other cyclohexane derivatives with similar structure as well as enhancing the development of feasible treatment technologies to mitigate these compounds.
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Aerobic and anaerobic microbial degradation of crude (4-methylcyclohexyl) methanol in river sediments
SCIENCE OF THE TOTAL ENVIRONMENT, 2016Co-Authors: Li Yuan, Zhi Wei, Liu Yangsheng, Smiley Elizabeth, Gallagher Daniel, Xi Chen, Dietrich Andrea, Zhang HusenAbstract:Cyclohexane and some of its derivatives have been a major concern because of their significant adverse human health effects and widespread occurrence in the environment. The 2014 West Virginia chemical spill has raised public attention to (4-methylcyclohexyl) methanol (4-MCHM), one cyclohexane derivative, which is widely used in Coal Processing but largely ignored. In particular, the environmental fate of its primary components, cis- and trans-4-MCHM, remains largely unexplored. This study aimed to investigate the degradation kinetics and mineralization of cis- and trans-4-MCHM by sediment microorganisms under aerobic and anaerobic conditions. We found the removal of cis- and trans-4-MCHM was mainly attributed to biodegradation with little contribution from sorption. A nearly complete aerobic degradation of 4-MCHM occurred within 14 days, whereas the anaerobic degradation was reluctant with residual percentages of 62.6% of cis-4-MCHM and 85.0% of trans-4MCHM after 16-day incubation. The cis-4-MCHM was degraded faster than the trans under both aerobic and anaerobic conditions, indicating an isomer-specific degradation could occur during the 4-MCHM degradation. Nitrate addition enhanced 4-MCHM mineralization by about 50% under both aerobic and anaerobic conditions. Both cis- and trans-4-MCHM fit well with the first-order kinetic model with respective degradation rates of 0.46-0.52 and 0.19-0.31 day(-1) under aerobic condition. Respective degradation rates of 0.041-0.095 and 0.013-0.052 day(-1) occurred under anaerobic condition. One bacterial strain capable of effectively degrading 4MCHM isomers was isolated from river sediments and identified as Bacillus pumilus at the species level based on 16S rRNA gene sequence and 97% identity. Our findings will provide critical information for improving the prediction of the environmental fate of 4-MCHM and other cyclohexane derivatives with similar structure as well as enhancing the development of feasible treatment technologies to mitigate these compounds. (C) 2015 Elsevier B.V. All rights reserved.Virginia Tech College of Engineering; China Scholarship Council; National Science Foundation [1424234]SCI(E)EIPubMedARTICLEyshliu@pku.edu.cn; husen@vt.edu78-8654
Adam Smolinski - One of the best experts on this subject based on the ideXlab platform.
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Utilization of Carbon Dioxide in Coal Gasification—An Experimental Study
'MDPI AG', 2019Co-Authors: Janusz Zdeb, Natalia Howaniec, Adam SmolinskiAbstract:Utilization of Coal in the current energy sector requires implementation of highly-efficient technologies to meet the dual targets of increased energy-efficiency and reduced carbon footprint. Efforts are being made to develop gasification systems with lower unit emissions of carbon dioxide and other contaminants, capable of handling various feedstocks and flexible in terms of products generated (synthesis gas, hydrogen, heat and electricity). The utilization of captured carbon dioxide and waste heat in industrial processes are considered to further contribute to the advancements in energy-efficient and low-emission technological solutions. This paper presents the experimental results on the incorporation of carbon dioxide into the valorization cycle as a reactant in Coal gasification. Tests were performed on a laboratory scale moving bed gasifier using three system configurations with various simulated waste heat utilization scenarios. The temperature range covered 700, 800 and 900 °C and the gasification agents used were carbon dioxide, oxygen and the mixture of 30 vol.% carbon dioxide in oxygen. The combined effect of the process parameters applied on the efficiency of Coal Processing in terms of the gas yields, composition and calorific value was studied and the experimental data were explored using Principal Component Analysis
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assessment of emission of selected gaseous components from Coal Processing waste storage site
Sustainability, 2018Co-Authors: Natalia Howaniec, Patrycja Kunagwoździewicz, Adam SmolinskiAbstract:Coal mine waste dumps are often thermally active objects with exhalation zones emitting exhaust gases, both inorganic and organic, including polycyclic aromatic hydrocarbons, phenols and BTEX hydrocarbons. The genotoxic, mutagenic and carcinogenic properties of polycyclic aromatic hydrocarbons make the monitoring of their emissions of particular importance. In this paper, the emissions of polycyclic aromatic hydrocarbons from exhalation zones of selected mine waste dumps located in Poland are presented. The experimental data set was analyzed with the application of the Hierarchical Clustering Analysis. The compounds of two- and three-cyclic hydrocarbons, such as naphthalene, acenaphthene, fluorene, phenanthrene and anthracene, were quantified in the gaseous samples tested. The compounds with a greater number of aromatic rings, such as fluoranthene, pyrene, benzo[a]anthracene and chrysene were characteristic only for some of the mine waste dumps tested.
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Reactivity of chars gasified in a fixed bed reactor with the potential utilization of excess process heat
Elsevier, 2017Co-Authors: Magdalena Cempa, Adam SmolinskiAbstract:The aim of the work presented in this paper was to determine the reactivity of chars and their selection for further research purposes concerning Coal gasification processes with the utilization of process excess heat. Char reactivity can be defined as the ability of Coal to react with such reactants as steam, oxygen or carbon dioxide. Reactivity determines reaction rates and therefore it is a decisive factor relating to the efficiency of combustion and gasification processes. In light of the above, reactivity may be regarded as an important parameter to be considered in the design and operation of the industrial systems of Coal Processing. The experimental work was conducted by means of a thermogravimetric analyzer (TGA) at temperature ranges of 700, 800 and 900 °C, with oxygen as a gasifying agent. The parameters of maximum reactivity Rmax as well as of 50% of the conversion reactivity R50 were calculated. The times tmax and t50 necessary for attaining the maximum reactivity Rmax and 50% conversion reactivity R50 were also determined. The correlation between the experimentally determined values of Rmax, R50, tmax and t50,additionally the physico-chemical parameters of the Coals were examined by means of PCA analysis
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steam co gasification of Coal and biomass synergy in reactivity of fuel blends chars
International Journal of Hydrogen Energy, 2013Co-Authors: Natalia Howaniec, Adam SmolinskiAbstract:Abstract Development of clean Coal technologies is the answer to increasing energy demand and environmental concerns related to conventional Coal Processing technologies. The technologies of fossil fuel gasification are technically proven and commercially available. Attempts of utilization of waste materials and renewable energy resources in gasification-based energy generation systems has been made, but wide application of such systems is still hindered by issues inherently combined with the characteristics of the materials. These include discontinuous supplies of a fuel of limited resources and varying composition resulting in poor economy of small-scale systems and operating problems related to tars formation and corrosion, especially when biomass utilization is considered. In the light of the above co-gasification seems to offer several advantages through mitigation of undesired effects of both carbon-intensive utilization of Coal and low efficient and troublesome operation of biomass/waste-fed gasification systems. The experimental results presented in the paper address the issues of determination of potential synergy effects resulting from the utilization of fuel blends composed of materials of various physical and chemical characteristics, which are still insufficiently discussed in the literature, especially when hydrogen-rich gas production in co-gasification is concerned. The results of reactivity tests of fuel blends of Coal and energy crops biomass in the process of steam co-gasification in a laboratory scale fixed bed reactor at 700, 800 and 900 °C are given proving the synergy effect in co-gasification reflected in increased reactivity of fuel blends when compared to Coal and biomass chars reactivity under similar process conditions.
R Q Honaker - One of the best experts on this subject based on the ideXlab platform.
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long term leaching characteristic study of Coal Processing waste streams
Chemosphere, 2020Co-Authors: Mohammad Rezaee, R Q HonakerAbstract:Abstract A study of the mobility of major and potentially hazardous trace elements from Coal Processing waste materials was conducted using two types of leaching tests. The baseline leaching test simulates stable waste storage under water, whereas the kinetic test models the storage of waste under more variable conditions including intermittent exposure to air and variations in humidity. Coarse and fine refuse materials were obtained from three commercial Coal preparation plants that were being used to upgrade US bituminous run-of-mine Coal containing low-to-high amounts of pyritic sulfur. X-ray diffraction analyses revealed a large variation in mineralogy between the coarse and fine refuse streams due to the mineral fractionation that occurs in the Processing units and plant. The coarse refuse samples contained higher pyrite contents while the fine refuse samples had high clay content and a minor amount of calcite. This variation in mineralogy resulted in relatively large difference in the leaching characteristics of the waste streams. The most acidic pH and highest release of trace elements were observed in the leachate of coarse refuse containing medium-to-high amounts of Coal pyrite, while the fine refuse samples released lower amounts of trace elements in their circumneutral leachate. The least amount of trace elements was observed in the leachate of low pyritic refuse streams. The test data suggested that the most effective disposal practice for Coal waste material is segregation and isolation of the Coal pyrite and co-disposal of the coarse and fine refuse streams.
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leaching of rare earth elements from an illinois basin Coal source
Journal of Rare Earths, 2019Co-Authors: Xinbo Yang, Joshua M Werner, R Q HonakerAbstract:Abstract The existence of rare earth elements (REEs) in Coal sources at elevated concentrations has been the focus of several studies over the past decade. However, limited research has been conducted on methods to recover and refine the REEs. This paper reports the results of a detailed study into the potential of selectively recovering REEs in an Illinois basin Coal source by leaching. Leaching characteristics are obtained for several segments obtained from a core sample as well as three different reject materials collected at a Coal Processing plant. Using a 1.2 mol/L sulfuric acid solution at 75 °C, over 60% REE recovery is achieved from the direct floor and an inner parting material as well as the Coal-rich core segments that are pretreated by low-temperature plasma oxidation to obtain access to the micro-dispersed mineral matter. In the leachable parting material, fluorapatite is detected by XRD analysis, which is one of the more soluble phosphate minerals with a documented association with REEs. For the three plant reject samples, the leaching recovery values obtained for the heavy REEs are higher than those obtained for the light REEs under the standard leaching conditions and when 0.1 mol/L (NH4)2SO4 was used to extract REEs by an ion exchange mechanism. Thermal activation by roasting or chemical activation by pretreatment using 8 mol/L NaOH solution increases the total REE recovery with significantly higher gains obtained for the light REEs. Leaching kinetics are relatively fast within the first 2 h and then slow to provide relatively low overall recovery values under the standard test conditions for the coarse and fine reject samples. However, significantly higher recovery values are realized when treating mixed-phase (middling) particles existing within the coarse reject material.
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designing and operating fine Coal Processing circuits to meet market specifications
International Journal of Coal Preparation and Utilization, 2014Co-Authors: G H Luttrell, Peter Bethell, R Q HonakerAbstract:Fine Coal cleaning circuits in operating preparation plants worldwide vary significantly in the technologies used for upgrading and dewatering Coal as well as the overall circuit layout. The differences are often due to the cleanability characteristics of the Coal and the varying market specifications. This article presents the use of plant optimization methodology based on the constant incremental quality concept toward selection of the fine Coal cleaning and dewatering technologies required for maximizing plant yield. The applications of the technologies in various circuit layouts are presented with respect to targeted markets and discussed using case studies.