Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced t...Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced technologies that has potential to be used in a carbon constrained economy. However, gasification availability at several commercial demonstrations had run into problems associated with fouling of syngas coolers due to unpredictable flyash formation and unburnt carbon losses. Computer models of gasifiers are emerging as a powerful tool to predict gasifier performance and reliability, without expensive testing. Most computer models used to simulate gasifiers tend to model coal as a homogenous entity based on bulk properties. However, coal is a heterogeneous material and comminution during feedstock preparation produces particle classes with different physical and chemical properties. It is crucial to characterize the heterogeneity of the feedstocks used by entrained flow gasifiers. To this end, a low ash US bituminous coal that could be used as a gasifier feedstock was segregated into density and size fractions to represent the major mineral matter distributions in the coal. Float and sink method and sieving were employed to partition the ground coal. The organic and inorganic content of all density fractions was characterized for particle size distribution, heating value, ultimate analysis, proximate analysis, mineral matter composition, ash composition, and petrographic components, while size fractions were characterized for heating value, ash composition, ultimate and proximate analysis. The proximate, ultimate and high heating value analysis showed that variation in these values is limited across the range of size fractions, while the heterogeneity is significant over the range of density fractions. With respect to inorganics, the mineral matter in the heavy density fractions contribute significantly to the ash yield in the coal while contributing very little to its heating value. The ash yield across the size fractions exhibits a bimodal distribution. The heterogeneity is also significant with respect to the base-to-acid ratio across the size and density fractions. The results indicate that the variations in organic and inorganic content over a range of density and size classes are significant, even in the low ash, vitrinite rich coal sample characterized here. Incorporating this information appropriately into particle population models used in gasifier simulations will significantly enhance their accuracy of performance predictions.展开更多
Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensi...Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines.展开更多
This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently estab...This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently established carbon peak and carbon neutralization targets,this paper put forward the main problems associated with the green and low-carbon development and utilization of coal.Five key technological innovation directions in mining were proposed,including green coal development,intelligent and efficient mining,low-carbon utilization and conversion of coal,energy conservation and emission reduction,carbon capture,utilization and storage(CCUS).Focusing on the above technological innovation directions,it is suggested to carry out three basic theories,including the theory of green efficient intelligent mining,clean and low-carbon utilization and transformation of coal,and CCUS.Meanwhile,it is proposed to develop 12 key technologies,including green coal mining and ecological environment protection,efficient coal mining and intelligent mine construction,key technologies and equipment for efficient coal processing,underground coal gasification and mining,ultra-high parameter and ultra-supercritical power generation technology,intelligent and flexible coal-fired power generation technology,new power cycle coal-fired power generation technology,the development of coal-based special fuels,coal-based bulk and specialty chemicals,energy conservation and consumption reduction,large-scale and low-cost carbon capture,CO_(2) utilization and storage.Finally,necessary measures from the governmental perspective were also proposed.展开更多
The target of the text is to scientifically appraise dynamic development of surface deformation in subsidence area and its influence on groundwork stability of natural pipe and then adopt some technological measures t...The target of the text is to scientifically appraise dynamic development of surface deformation in subsidence area and its influence on groundwork stability of natural pipe and then adopt some technological measures to ensure safe circulation of natural pipeline. Analysed the influence on natural pipeline from coal mining subsidence in the way of pipeline grade variation, vertical curve variation, transverse deformation, horizontal pull and compression deformation and pipe stress variation etc., and described detailed surface subsidence product and its used time among initial phase, active phase and decline phase in the course of surface movement deformation time. In the context of considering surface subsidence that doesn＇t reach basic latter end and residual subsidence quantity, the text confirmed the calculation method of residual deformation in surface subsidence area, and gave the technological measures about building natural gas pipeline in subsidence area finally.展开更多
Methane and carbon dioxide hydrates are one of the possible forms in which these gases exist in natural coal(for more detailed discussion see Refs [1,2]). In this work, the decomposition of carbon dioxide hydrate in f...Methane and carbon dioxide hydrates are one of the possible forms in which these gases exist in natural coal(for more detailed discussion see Refs [1,2]). In this work, the decomposition of carbon dioxide hydrate in five samples of natural coal differing from each other in metamorphism degree was investigated experimentally. Carbon dioxide hydrate dispersed in coals was synthesized from water adsorbed in these coals. During a linear temperature rise in an autoclave with the coal + hydrate sample the hydrate decomposition manifests itself as a step of increase in gas pressure, accompanied by a decrease/stabilization of the temperature of coal sample. The dependencies of the amount of hydrate formed on initial coal humidity and on gas pressure during hydrate formation were studied. It was demonstrated that each coal sample is characterized by its own humidity threshold below which hydrate formation in natural coal is impossible. With an increase in gas pressure, the amount of water transformed into hydrate increases. For the studied coal samples, the decomposition of carbon dioxide hydrates proceeds within a definite temperature and pressure range, and this range is close to the curve of phase equilibrium for bulk hydrate.展开更多
This paper briefs the current clean production and consumption levels of coal in China and the pollution harmbrought to the atmospheric environment, present status and orientation of clean coal technology development ...This paper briefs the current clean production and consumption levels of coal in China and the pollution harmbrought to the atmospheric environment, present status and orientation of clean coal technology development in Chinacoal industry, progress and perspective of clean coal power generation technology in China, as well as application andmarket of flue gas desulphurization technology in coal-fired power plants.[展开更多
Coal is the primary fossil fuel most used in the world for the electricity generation, iron making, and cement/concrete and chemical production. However, utilization of coal also results in emissions of CO_2, SO_x, NO...Coal is the primary fossil fuel most used in the world for the electricity generation, iron making, and cement/concrete and chemical production. However, utilization of coal also results in emissions of CO_2, SO_x, NO_x and other noxious compounds. The development of clean coal technology(CCT) is a main issue to maintain a clean environment. CCT in Japan is considered the highest level in the world. In this review, the developing CCTs in Japan including high efficiency combustion technologies, advanced gasification technologies, CO_2 recovery and utilization technologies, and flue gas cleaning technologies are introduced and discussed. It is expected to provide some new view-of-points for CCT development.展开更多
文摘Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced technologies that has potential to be used in a carbon constrained economy. However, gasification availability at several commercial demonstrations had run into problems associated with fouling of syngas coolers due to unpredictable flyash formation and unburnt carbon losses. Computer models of gasifiers are emerging as a powerful tool to predict gasifier performance and reliability, without expensive testing. Most computer models used to simulate gasifiers tend to model coal as a homogenous entity based on bulk properties. However, coal is a heterogeneous material and comminution during feedstock preparation produces particle classes with different physical and chemical properties. It is crucial to characterize the heterogeneity of the feedstocks used by entrained flow gasifiers. To this end, a low ash US bituminous coal that could be used as a gasifier feedstock was segregated into density and size fractions to represent the major mineral matter distributions in the coal. Float and sink method and sieving were employed to partition the ground coal. The organic and inorganic content of all density fractions was characterized for particle size distribution, heating value, ultimate analysis, proximate analysis, mineral matter composition, ash composition, and petrographic components, while size fractions were characterized for heating value, ash composition, ultimate and proximate analysis. The proximate, ultimate and high heating value analysis showed that variation in these values is limited across the range of size fractions, while the heterogeneity is significant over the range of density fractions. With respect to inorganics, the mineral matter in the heavy density fractions contribute significantly to the ash yield in the coal while contributing very little to its heating value. The ash yield across the size fractions exhibits a bimodal distribution. The heterogeneity is also significant with respect to the base-to-acid ratio across the size and density fractions. The results indicate that the variations in organic and inorganic content over a range of density and size classes are significant, even in the low ash, vitrinite rich coal sample characterized here. Incorporating this information appropriately into particle population models used in gasifier simulations will significantly enhance their accuracy of performance predictions.
基金Projects 50574072, 50874089 and 50534049 supported by the National Natural Science Foundation of China08JK366 by the Special Scientific Foundation of Educational Committee of Shaanxi Province
文摘Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines.
文摘This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently established carbon peak and carbon neutralization targets,this paper put forward the main problems associated with the green and low-carbon development and utilization of coal.Five key technological innovation directions in mining were proposed,including green coal development,intelligent and efficient mining,low-carbon utilization and conversion of coal,energy conservation and emission reduction,carbon capture,utilization and storage(CCUS).Focusing on the above technological innovation directions,it is suggested to carry out three basic theories,including the theory of green efficient intelligent mining,clean and low-carbon utilization and transformation of coal,and CCUS.Meanwhile,it is proposed to develop 12 key technologies,including green coal mining and ecological environment protection,efficient coal mining and intelligent mine construction,key technologies and equipment for efficient coal processing,underground coal gasification and mining,ultra-high parameter and ultra-supercritical power generation technology,intelligent and flexible coal-fired power generation technology,new power cycle coal-fired power generation technology,the development of coal-based special fuels,coal-based bulk and specialty chemicals,energy conservation and consumption reduction,large-scale and low-cost carbon capture,CO_(2) utilization and storage.Finally,necessary measures from the governmental perspective were also proposed.
文摘The target of the text is to scientifically appraise dynamic development of surface deformation in subsidence area and its influence on groundwork stability of natural pipe and then adopt some technological measures to ensure safe circulation of natural pipeline. Analysed the influence on natural pipeline from coal mining subsidence in the way of pipeline grade variation, vertical curve variation, transverse deformation, horizontal pull and compression deformation and pipe stress variation etc., and described detailed surface subsidence product and its used time among initial phase, active phase and decline phase in the course of surface movement deformation time. In the context of considering surface subsidence that doesn＇t reach basic latter end and residual subsidence quantity, the text confirmed the calculation method of residual deformation in surface subsidence area, and gave the technological measures about building natural gas pipeline in subsidence area finally.
基金supported by the project №18 "Study of the physicochemical properties of hydrate-containing rocks for the development of remote sensing methods and the characteristics of natural accumulations of gas hydrates" of the Integrated Basic Research Program of the Siberian Branch of the Russian Academy of Sciences.
文摘Methane and carbon dioxide hydrates are one of the possible forms in which these gases exist in natural coal(for more detailed discussion see Refs [1,2]). In this work, the decomposition of carbon dioxide hydrate in five samples of natural coal differing from each other in metamorphism degree was investigated experimentally. Carbon dioxide hydrate dispersed in coals was synthesized from water adsorbed in these coals. During a linear temperature rise in an autoclave with the coal + hydrate sample the hydrate decomposition manifests itself as a step of increase in gas pressure, accompanied by a decrease/stabilization of the temperature of coal sample. The dependencies of the amount of hydrate formed on initial coal humidity and on gas pressure during hydrate formation were studied. It was demonstrated that each coal sample is characterized by its own humidity threshold below which hydrate formation in natural coal is impossible. With an increase in gas pressure, the amount of water transformed into hydrate increases. For the studied coal samples, the decomposition of carbon dioxide hydrates proceeds within a definite temperature and pressure range, and this range is close to the curve of phase equilibrium for bulk hydrate.
文摘This paper briefs the current clean production and consumption levels of coal in China and the pollution harmbrought to the atmospheric environment, present status and orientation of clean coal technology development in Chinacoal industry, progress and perspective of clean coal power generation technology in China, as well as application andmarket of flue gas desulphurization technology in coal-fired power plants.[
文摘Coal is the primary fossil fuel most used in the world for the electricity generation, iron making, and cement/concrete and chemical production. However, utilization of coal also results in emissions of CO_2, SO_x, NO_x and other noxious compounds. The development of clean coal technology(CCT) is a main issue to maintain a clean environment. CCT in Japan is considered the highest level in the world. In this review, the developing CCTs in Japan including high efficiency combustion technologies, advanced gasification technologies, CO_2 recovery and utilization technologies, and flue gas cleaning technologies are introduced and discussed. It is expected to provide some new view-of-points for CCT development.
