Damage statistical mechanics model of horizontal section height in the top caving was constructed in the paper. The influence factors including supporting pressure, dip angle and characteristic of coal on horizontal s...Damage statistical mechanics model of horizontal section height in the top caving was constructed in the paper. The influence factors including supporting pressure, dip angle and characteristic of coal on horizontal section height were analyzed as well. By terms of the practice project analysis, the horizontal section height increases with the increase of dip angle β and thickness of coal seam M. Dip angle of coal seam β has tremendous impact on horizontal section height, while thickness of coal seam M has slight impact. When thickness of coal seam is below 10m, horizontal section height increases sharply. While thickness exceeds 15m, it is not major factor influencing on horizontal section height any long.展开更多
Given the analysis of underground pressure, a stress calculation model of coal floor stress has been established based on a theory of elasticity. The model presents the law of stress distribution on the relatively fix...Given the analysis of underground pressure, a stress calculation model of coal floor stress has been established based on a theory of elasticity. The model presents the law of stress distribution on the relatively fixed position of the mining coal floor: the extent of stress variation in a fixed floor position decreases gradually along with depth, the decreasing rate of the vertical stress is clearly larger than that of the horizontal stress at a specific depth. The direction of the maximum principal stress changes gradually from a vertical direction to a horizontal direction with the advance of the working face. The deformation and permeability of the rock mass of the coal floor are obtained by contrasting the difference of the principal stress established from theoretical calculations with curves of stress-strain and permeability-strain from tests, which is an important mechanical basis for preventing water inrush from confined aquifers.展开更多
Coal-formed gas generated from the Permo-Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin,offshore eastern China.However,the proven gas r...Coal-formed gas generated from the Permo-Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin,offshore eastern China.However,the proven gas reserves from this source rock remain low to date,and the distribution characteristics and accumulation model for the coal-formed gas are not clear.Here we review the coal-formed gas deposits formed from the Permo-Carboniferous coal measures in the Bohai Bay Basin.The accumulations are scattered,and dominated by middle-small sized gas fields,of which the proven reserves ranging from 0.002 to 149.4×108 m3 with an average of 44.30×108 m3 and a mid-point of 8.16×108 m3.The commercially valuable gas fields are mainly found in the central and southern parts of the basin.Vertically,the coal-formed gas is accumulated at multiple stratigraphic levels from Paleogene to Archaeozoic,among which the Paleogene and PermoCarboniferous are the main reservoir strata.According to the transporting pathway,filling mechanism and the relationship between source rocks and reservoir,the coal-formed gas accumulation model can be defined into three types:"Upward migrated,fault transported gas"accumulation model,"Laterally migrated,sandbody transported gas"accumulation model,and"Downward migrated,sub-source,fracture transported gas"accumulation model.Source rock distribution,thermal evolution and hydrocarbon generation capacity are the fundamental controlling factors for the macro distribution and enrichment of the coal-formed gas.The fault activity and the configuration of fault and caprock control the vertical enrichment pattern.展开更多
Isothermal and non-isothermal gasification kinetics of coal char were investigated by using thermogravimetric analysis(TGA) in CO2 atmosphere, and the experimental data were interpreted with the aids of random pore mo...Isothermal and non-isothermal gasification kinetics of coal char were investigated by using thermogravimetric analysis(TGA) in CO2 atmosphere, and the experimental data were interpreted with the aids of random pore model(RPM), unreacted shrinking core model(URCM) and volume model(VM). With the increase of heating rate, gasification curve moves into high temperature zone and peak rate of gasification increases; with the increase of gasification temperature, gasification rate increases and the total time of gasification is shortened. The increase of both heating rate and gasification temperature could improve gasification process of coal char. Kinetics analysis indicates that experimental data agree better with the RPM than with the other two models. The apparent activation energy of non-isothermal and isothermal gasification of coal char using RPM is 193.9 k J/mol and 212.6 k J/mol respectively, which are in accordance with reported data. Gasification process of coal char under different heating rates and different temperatures are predicted by the RPM derived in this study, and it is found that the RPM predicts the reaction process satisfactorily.展开更多
Coal exhibits different creep behaviours when filled with different amounts of gas. Creep tests of coal filled with 0 and 0.5 MPa gas were performed, and strain under different axial stress was compared.The three cree...Coal exhibits different creep behaviours when filled with different amounts of gas. Creep tests of coal filled with 0 and 0.5 MPa gas were performed, and strain under different axial stress was compared.The three creep constitutive models which were analysed using the method fitting experimental data for determining which creep model can reflect the creep process of the test best. The results show that the deformation of coal filled with 0.5 MPa gas is more higher than that of coal filled with 0 MPa gas under the same axial stress. Gas plays a positive effect on the deformation of coal process and will accelerate creep process. And gas will reduce coal intensity and change coal creep properties.Compared with Nishihara Model and Extensional Nishihara Model, Burgers Model can reflect the three stages of creep process of coal filled with gas better. The research results can contribute to reveal coal and gas outburst mechanism.展开更多
Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical w...Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical workers. Based on the viewpoint of ‘vague/clear', the species classification and accurate analysis on coal were conducted by using the natural clustering all-component separation method. A more systematic and detailed coal embedded structure model theory which is suitable for coal of all ranks was developed from the previous one and a more complete theoretical system about the component and structure of coal was constructed. The whole establishment process of the theory was summarized and some of the main support data and analysis test results, including TEM, AFM, FTIR, GC/MS, MALDI/TOF/MS, DART/MSD, fractal analysis and so on were provided. The coal embedded structure theory fully considers both the identity and the particularity of all-rank coal, reflects the coal component and structure in the full range of coal rank, solves the systematic cognitive problem of coal component and structure on macro and micro level, and provides a valuable and meaningful theoretical approach for the coal processing and conversion technology.展开更多
Electrolytic reductions of oxygenic functional groups (OFGs) on coal surface and coal model compounds with OFGs in an aqueous NaCl solution are studied by electrochemical methods combined with GC/MS, GC and FTIR analy...Electrolytic reductions of oxygenic functional groups (OFGs) on coal surface and coal model compounds with OFGs in an aqueous NaCl solution are studied by electrochemical methods combined with GC/MS, GC and FTIR analyses. Different electrode reactions, their corresponding potentials and dynamic equations during the processes are investigated. The results show that benzoic acid, benzaldehyde, benzalcohol and hypnone are reduced to benzaldehyde and benzalcohol, methoxybenzene and benzalcohol, toluene and styrene, respectively, at the cathode. The corresponding electrode potentials and dynamic equations are determined. The electrolytic reduction also leads to an increase in the contents of hydroxyl groups and aliphatic moieties and a corresponding decrease in those of carboxyl and carbonyl groups in Nantong coal, a high-sulfur coal, an enhancement in the flotation desulfurization of the coal. ER also reduces organic sulfur and FeS2 in the coal.展开更多
The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and witho...The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and without catalysts, a series of experiments were conducted at different temperatures, pressures and reaction time. Gas chromatography-mass spectrometry and gas chromatography were used to identify and quantify the reactants and products respectively. The conversion of 2-naphthol rises with the increase of reaction temperature, initial pressure and catalyst amount. The results indicated that tem- perature had a significant effect on 2-naphthol conversion, which promoted the dehydroxylation reaction. However, initial pressure had an important influence on the hydrogenation of 2-naphthol and naphthalene. The iron catalyst plays a significant role of cracking instead of hydrogenation. It is concluded that the harsh reaction conditions of high temperature, high pressure, and more catalyst are conducive to promoting dehydroxylation of 2-naphthol. The reaction mechanism was put forward based the experimental results, in which 2-tetralone was an intermediate.展开更多
Due to the change of initial stress state caused by roadway excavation, the permeability of the coal body may be changed during the excavation process. In this paper, according to the different stress states, the coal...Due to the change of initial stress state caused by roadway excavation, the permeability of the coal body may be changed during the excavation process. In this paper, according to the different stress states, the coal around the roadway was divided into the seepage open zone, seepage orientation zone, seepage decay zone and original seepage zone along the radial direction of the roadway. The loaded gassy coal was treated as a viscoelastic and plastic softened medium, and the mechanical behaviors of the viscoelastic zone, plastic softened zone and broken zone around the roadway were analyzed with the consideration of the loading creep, softening and expansion effect of the gassy coal. According to the law of conservation of mass and the Darcy law, the flow-solid coupled model for the gas transportation of the coal around the roadway was established considering the dynamic evolution of the adsorption characteristics, porosity and permeability of the coal, and the simulation software COMSOL was utilized to numerically simulate the stress state and gas flow regularity around the coal, which provided meaningful reference for investigating the stability of the coal and rock around the roadway.展开更多
This paper explores possible synergies between techniques used to minimise seismicity in deep South African gold mines and their applicability to control coal bumps. The paper gives a summary of the techniques used in...This paper explores possible synergies between techniques used to minimise seismicity in deep South African gold mines and their applicability to control coal bumps. The paper gives a summary of the techniques used in the deep gold mines and a critical appraisal if these are useful in coal mines. The techniques typically include control of mining rate, preconditioning, optimisation of extraction sequences and centralised blasting. Of particular interest to the coal bump problem is an experimental limit equilibrium fracture zone model implemented in a displacement discontinuity code. This was recently developed for the gold mines to enable the interactive analysis of complex tabular mine layout extraction sequences. The model specifically accommodates energy dissipation computations in the developing fracture zone near the edges of these excavations. This allows the released energy to be used as a surrogate measure of ongoing seismic activity and addresses a number of the weaknesses in the traditional usage of this quantity as a criterion for the design of seismically active layouts. This paper investigates the application of the model to a hypothetical coal longwall layout and the specific problem of coal bumps.展开更多
In order to predict blended coal's property accurately, a new kind of hybrid prediction model based on principal component analysis (PCA) and support vector machine (SVM) was established. PCA was used to transform...In order to predict blended coal's property accurately, a new kind of hybrid prediction model based on principal component analysis (PCA) and support vector machine (SVM) was established. PCA was used to transform the high-dimensional and correlative influencing factors data to low-dimensional principal component subspace. Well-trained SVM was used to extract influencing factors as input to predict blended coal's property. Then experiments were made by using the real data, and the results were compared with weighted averaging method (WAM) and BP neural network. The results show that PCA-SVM has higher prediction accuracy in the condition of few data, thus the hybrid model is of great use in the domain of power coal blending.展开更多
This study investigated the isothermal gasification reactivity of biomass char (BC) and coal char (CC) blended at mass ratios of 1:3, 1:1, and 3:1 via isothermal thermogravimelric analysis (TGA) at 900, 950, ...This study investigated the isothermal gasification reactivity of biomass char (BC) and coal char (CC) blended at mass ratios of 1:3, 1:1, and 3:1 via isothermal thermogravimelric analysis (TGA) at 900, 950, and 1000℃ under CO2. With an increase in BC blending ra- tio, there were an increase in gasification rate and a shortening of gasification time. This could be attributed to the high specific surface area of BC and the high uniformity of carbon structures in CC when compared to those in BC. Three representative gas-solid kinetic models, namely, the volumetric model (VM), grain model (GM), and random pore model (RPM), were applied to describe the reaction behavior of the char. Among them, the RPM model was considered the best model to describe the reactivity of the char gasification reaction. The activa- tion energy of BC and CC isothermal gasification as determined using the RPM model was found to be 126.7 kJ/mol and 210.2 kJ/mol, re- spectively. The activation energy was minimum (123.1 kJ/mol) for the BC blending ratio of 75%. Synergistic effect manifested at all mass ratios of the blended char, which increased with the gasification temperature.展开更多
On the basis of the study on the occurrence and distribution of sulfur in the Late Permiau high-sulrur coals of Sichuan .Southwest China,the paper discusses the geological ractors influencing sulfur occurrence in coal...On the basis of the study on the occurrence and distribution of sulfur in the Late Permiau high-sulrur coals of Sichuan .Southwest China,the paper discusses the geological ractors influencing sulfur occurrence in coals, and suggests two evolutionary motlels, i. e. a directly depositional pyrite series(euhedral crystal→aggregate→glomerocryst ) and complex genetic series (mini→granular, framboid→spherical→nodular,lumpy pyrite). They are of theoretically and actually important significance not only in the explanation to the difference in composition of varioas types of coal pyrites,but also in the understanding of the mechanism of physical properties (magnetic,surface property) of pyrites. By a comprehansive analysis,a genetic model of sulfur in the Late Permian coal of Sichuan has been established.展开更多
In mining industries no mines are identical and each mine has its own unique set of mining conditions. In order to study thecondition of mines for efficiency, safety and economy reasons, a fuzzy model is presented bas...In mining industries no mines are identical and each mine has its own unique set of mining conditions. In order to study thecondition of mines for efficiency, safety and economy reasons, a fuzzy model is presented based on fuzzy evaluation. Relevant data fromfive mines were collected and the model was used to evaluate the mining condition of these mines. The evaluation results are in conformity with the real situation.展开更多
The data on the coal production and consumption in Jilin Province for the last ten years were collected,and the Grey System GM( 1,1) model and unary linear regression model were applied to predict the coal consumption...The data on the coal production and consumption in Jilin Province for the last ten years were collected,and the Grey System GM( 1,1) model and unary linear regression model were applied to predict the coal consumption of Jilin Production in 2014 and 2015. Through calculation,the predictive value on the coal consumption of Jilin Province was attained,namely consumption of 2014 is 114. 84 × 106 t and of 2015 is 117. 98 ×106t,respectively. Analysis of error data indicated that the predicted accuracy of Grey System GM( 1,1) model on the coal consumption in Jilin Province improved 0. 21% in comparison to unary linear regression model.展开更多
The Qinshui Basin in southeastern Shanxi Province is an important base for coalbed methane exploration and production in China.The methane reservoirs in this area are the Carboniferous and Permian coals and their thic...The Qinshui Basin in southeastern Shanxi Province is an important base for coalbed methane exploration and production in China.The methane reservoirs in this area are the Carboniferous and Permian coals and their thickness are strongly controlled by the depositional environments and the sequence stratigraphic framework.This paper analyzes the high-resolution sequence stratigraphy of the Permo-Carbo-展开更多
基金This work was financially supported by the National Natural Science fund of China (No.50274058).
文摘Damage statistical mechanics model of horizontal section height in the top caving was constructed in the paper. The influence factors including supporting pressure, dip angle and characteristic of coal on horizontal section height were analyzed as well. By terms of the practice project analysis, the horizontal section height increases with the increase of dip angle β and thickness of coal seam M. Dip angle of coal seam β has tremendous impact on horizontal section height, while thickness of coal seam M has slight impact. When thickness of coal seam is below 10m, horizontal section height increases sharply. While thickness exceeds 15m, it is not major factor influencing on horizontal section height any long.
文摘Given the analysis of underground pressure, a stress calculation model of coal floor stress has been established based on a theory of elasticity. The model presents the law of stress distribution on the relatively fixed position of the mining coal floor: the extent of stress variation in a fixed floor position decreases gradually along with depth, the decreasing rate of the vertical stress is clearly larger than that of the horizontal stress at a specific depth. The direction of the maximum principal stress changes gradually from a vertical direction to a horizontal direction with the advance of the working face. The deformation and permeability of the rock mass of the coal floor are obtained by contrasting the difference of the principal stress established from theoretical calculations with curves of stress-strain and permeability-strain from tests, which is an important mechanical basis for preventing water inrush from confined aquifers.
基金financial support from the National major projects (Item No.2016ZX05006-003)
文摘Coal-formed gas generated from the Permo-Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin,offshore eastern China.However,the proven gas reserves from this source rock remain low to date,and the distribution characteristics and accumulation model for the coal-formed gas are not clear.Here we review the coal-formed gas deposits formed from the Permo-Carboniferous coal measures in the Bohai Bay Basin.The accumulations are scattered,and dominated by middle-small sized gas fields,of which the proven reserves ranging from 0.002 to 149.4×108 m3 with an average of 44.30×108 m3 and a mid-point of 8.16×108 m3.The commercially valuable gas fields are mainly found in the central and southern parts of the basin.Vertically,the coal-formed gas is accumulated at multiple stratigraphic levels from Paleogene to Archaeozoic,among which the Paleogene and PermoCarboniferous are the main reservoir strata.According to the transporting pathway,filling mechanism and the relationship between source rocks and reservoir,the coal-formed gas accumulation model can be defined into three types:"Upward migrated,fault transported gas"accumulation model,"Laterally migrated,sandbody transported gas"accumulation model,and"Downward migrated,sub-source,fracture transported gas"accumulation model.Source rock distribution,thermal evolution and hydrocarbon generation capacity are the fundamental controlling factors for the macro distribution and enrichment of the coal-formed gas.The fault activity and the configuration of fault and caprock control the vertical enrichment pattern.
基金supported by the National Science Foundation of China & Baosteel under Grant (No. 51134008)the National Key Technology R&D Program in the 12th Five year Plan of China (No. 2011BAC01B02)
文摘Isothermal and non-isothermal gasification kinetics of coal char were investigated by using thermogravimetric analysis(TGA) in CO2 atmosphere, and the experimental data were interpreted with the aids of random pore model(RPM), unreacted shrinking core model(URCM) and volume model(VM). With the increase of heating rate, gasification curve moves into high temperature zone and peak rate of gasification increases; with the increase of gasification temperature, gasification rate increases and the total time of gasification is shortened. The increase of both heating rate and gasification temperature could improve gasification process of coal char. Kinetics analysis indicates that experimental data agree better with the RPM than with the other two models. The apparent activation energy of non-isothermal and isothermal gasification of coal char using RPM is 193.9 k J/mol and 212.6 k J/mol respectively, which are in accordance with reported data. Gasification process of coal char under different heating rates and different temperatures are predicted by the RPM derived in this study, and it is found that the RPM predicts the reaction process satisfactorily.
基金supported by National Natural Science Funds of China (No. 51304212)Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120023120005)+2 种基金Beijing Higher Education Young Elite Teacher Project (No. YETP0930)Fun-damental Research Funds for the Central Universities (No. 2009QZ09)Open Foundation of State Key Laboratory of Coal Resources and Safe Mining (No. SKLCRSM11KFB04)
文摘Coal exhibits different creep behaviours when filled with different amounts of gas. Creep tests of coal filled with 0 and 0.5 MPa gas were performed, and strain under different axial stress was compared.The three creep constitutive models which were analysed using the method fitting experimental data for determining which creep model can reflect the creep process of the test best. The results show that the deformation of coal filled with 0.5 MPa gas is more higher than that of coal filled with 0 MPa gas under the same axial stress. Gas plays a positive effect on the deformation of coal process and will accelerate creep process. And gas will reduce coal intensity and change coal creep properties.Compared with Nishihara Model and Extensional Nishihara Model, Burgers Model can reflect the three stages of creep process of coal filled with gas better. The research results can contribute to reveal coal and gas outburst mechanism.
基金financial provided by the National Natural Science Foundation of China (Nos. 50474066, 50874108, 51274201, and 51674260)the Coal Joint Fund from National Natural Science Foundation of China and Shenhua Group Corporation Limited (No. U1361116)the National Basic Research Program of China (No. 2012CB214900)
文摘Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical workers. Based on the viewpoint of ‘vague/clear', the species classification and accurate analysis on coal were conducted by using the natural clustering all-component separation method. A more systematic and detailed coal embedded structure model theory which is suitable for coal of all ranks was developed from the previous one and a more complete theoretical system about the component and structure of coal was constructed. The whole establishment process of the theory was summarized and some of the main support data and analysis test results, including TEM, AFM, FTIR, GC/MS, MALDI/TOF/MS, DART/MSD, fractal analysis and so on were provided. The coal embedded structure theory fully considers both the identity and the particularity of all-rank coal, reflects the coal component and structure in the full range of coal rank, solves the systematic cognitive problem of coal component and structure on macro and micro level, and provides a valuable and meaningful theoretical approach for the coal processing and conversion technology.
基金Project 2004CB217601 supported by the Special Fund for Major State Basic Research Projects
文摘Electrolytic reductions of oxygenic functional groups (OFGs) on coal surface and coal model compounds with OFGs in an aqueous NaCl solution are studied by electrochemical methods combined with GC/MS, GC and FTIR analyses. Different electrode reactions, their corresponding potentials and dynamic equations during the processes are investigated. The results show that benzoic acid, benzaldehyde, benzalcohol and hypnone are reduced to benzaldehyde and benzalcohol, methoxybenzene and benzalcohol, toluene and styrene, respectively, at the cathode. The corresponding electrode potentials and dynamic equations are determined. The electrolytic reduction also leads to an increase in the contents of hydroxyl groups and aliphatic moieties and a corresponding decrease in those of carboxyl and carbonyl groups in Nantong coal, a high-sulfur coal, an enhancement in the flotation desulfurization of the coal. ER also reduces organic sulfur and FeS2 in the coal.
文摘The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and without catalysts, a series of experiments were conducted at different temperatures, pressures and reaction time. Gas chromatography-mass spectrometry and gas chromatography were used to identify and quantify the reactants and products respectively. The conversion of 2-naphthol rises with the increase of reaction temperature, initial pressure and catalyst amount. The results indicated that tem- perature had a significant effect on 2-naphthol conversion, which promoted the dehydroxylation reaction. However, initial pressure had an important influence on the hydrogenation of 2-naphthol and naphthalene. The iron catalyst plays a significant role of cracking instead of hydrogenation. It is concluded that the harsh reaction conditions of high temperature, high pressure, and more catalyst are conducive to promoting dehydroxylation of 2-naphthol. The reaction mechanism was put forward based the experimental results, in which 2-tetralone was an intermediate.
基金the financial support from the National Natural Science Foundation for Young Scientists of China (Nos.51604116 and 51604096)Natural Science Foundation ofHenbei Province (No.E2016508036)+1 种基金Hebei State Key Laboratory of Mine Disaster Prevention (No.KJZH2017K08)Basic and Frontier Technology Research Project of Henan Province in 2016 (No.162300410031)
文摘Due to the change of initial stress state caused by roadway excavation, the permeability of the coal body may be changed during the excavation process. In this paper, according to the different stress states, the coal around the roadway was divided into the seepage open zone, seepage orientation zone, seepage decay zone and original seepage zone along the radial direction of the roadway. The loaded gassy coal was treated as a viscoelastic and plastic softened medium, and the mechanical behaviors of the viscoelastic zone, plastic softened zone and broken zone around the roadway were analyzed with the consideration of the loading creep, softening and expansion effect of the gassy coal. According to the law of conservation of mass and the Darcy law, the flow-solid coupled model for the gas transportation of the coal around the roadway was established considering the dynamic evolution of the adsorption characteristics, porosity and permeability of the coal, and the simulation software COMSOL was utilized to numerically simulate the stress state and gas flow regularity around the coal, which provided meaningful reference for investigating the stability of the coal and rock around the roadway.
文摘This paper explores possible synergies between techniques used to minimise seismicity in deep South African gold mines and their applicability to control coal bumps. The paper gives a summary of the techniques used in the deep gold mines and a critical appraisal if these are useful in coal mines. The techniques typically include control of mining rate, preconditioning, optimisation of extraction sequences and centralised blasting. Of particular interest to the coal bump problem is an experimental limit equilibrium fracture zone model implemented in a displacement discontinuity code. This was recently developed for the gold mines to enable the interactive analysis of complex tabular mine layout extraction sequences. The model specifically accommodates energy dissipation computations in the developing fracture zone near the edges of these excavations. This allows the released energy to be used as a surrogate measure of ongoing seismic activity and addresses a number of the weaknesses in the traditional usage of this quantity as a criterion for the design of seismically active layouts. This paper investigates the application of the model to a hypothetical coal longwall layout and the specific problem of coal bumps.
基金Project(50579101) supported by the National Natural Science Foundation of China
文摘In order to predict blended coal's property accurately, a new kind of hybrid prediction model based on principal component analysis (PCA) and support vector machine (SVM) was established. PCA was used to transform the high-dimensional and correlative influencing factors data to low-dimensional principal component subspace. Well-trained SVM was used to extract influencing factors as input to predict blended coal's property. Then experiments were made by using the real data, and the results were compared with weighted averaging method (WAM) and BP neural network. The results show that PCA-SVM has higher prediction accuracy in the condition of few data, thus the hybrid model is of great use in the domain of power coal blending.
基金financially supported by the National Natural Science Foundation of China (No. 51104014)
文摘This study investigated the isothermal gasification reactivity of biomass char (BC) and coal char (CC) blended at mass ratios of 1:3, 1:1, and 3:1 via isothermal thermogravimelric analysis (TGA) at 900, 950, and 1000℃ under CO2. With an increase in BC blending ra- tio, there were an increase in gasification rate and a shortening of gasification time. This could be attributed to the high specific surface area of BC and the high uniformity of carbon structures in CC when compared to those in BC. Three representative gas-solid kinetic models, namely, the volumetric model (VM), grain model (GM), and random pore model (RPM), were applied to describe the reaction behavior of the char. Among them, the RPM model was considered the best model to describe the reactivity of the char gasification reaction. The activa- tion energy of BC and CC isothermal gasification as determined using the RPM model was found to be 126.7 kJ/mol and 210.2 kJ/mol, re- spectively. The activation energy was minimum (123.1 kJ/mol) for the BC blending ratio of 75%. Synergistic effect manifested at all mass ratios of the blended char, which increased with the gasification temperature.
文摘On the basis of the study on the occurrence and distribution of sulfur in the Late Permiau high-sulrur coals of Sichuan .Southwest China,the paper discusses the geological ractors influencing sulfur occurrence in coals, and suggests two evolutionary motlels, i. e. a directly depositional pyrite series(euhedral crystal→aggregate→glomerocryst ) and complex genetic series (mini→granular, framboid→spherical→nodular,lumpy pyrite). They are of theoretically and actually important significance not only in the explanation to the difference in composition of varioas types of coal pyrites,but also in the understanding of the mechanism of physical properties (magnetic,surface property) of pyrites. By a comprehansive analysis,a genetic model of sulfur in the Late Permian coal of Sichuan has been established.
文摘In mining industries no mines are identical and each mine has its own unique set of mining conditions. In order to study thecondition of mines for efficiency, safety and economy reasons, a fuzzy model is presented based on fuzzy evaluation. Relevant data fromfive mines were collected and the model was used to evaluate the mining condition of these mines. The evaluation results are in conformity with the real situation.
基金Supported by project of National Natural Science Foundation of China(No.41272360)
文摘The data on the coal production and consumption in Jilin Province for the last ten years were collected,and the Grey System GM( 1,1) model and unary linear regression model were applied to predict the coal consumption of Jilin Production in 2014 and 2015. Through calculation,the predictive value on the coal consumption of Jilin Province was attained,namely consumption of 2014 is 114. 84 × 106 t and of 2015 is 117. 98 ×106t,respectively. Analysis of error data indicated that the predicted accuracy of Grey System GM( 1,1) model on the coal consumption in Jilin Province improved 0. 21% in comparison to unary linear regression model.
文摘The Qinshui Basin in southeastern Shanxi Province is an important base for coalbed methane exploration and production in China.The methane reservoirs in this area are the Carboniferous and Permian coals and their thickness are strongly controlled by the depositional environments and the sequence stratigraphic framework.This paper analyzes the high-resolution sequence stratigraphy of the Permo-Carbo-