The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimiz...The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.展开更多
In this research,molecular structure models were developed respectively for Shenhua coal vitrinite concentrates(SDV)and inertinite concentrates(SDI),on the basis of information on constitutional unit of Shenhau coal a...In this research,molecular structure models were developed respectively for Shenhua coal vitrinite concentrates(SDV)and inertinite concentrates(SDI),on the basis of information on constitutional unit of Shenhau coal and elemental analysis results obtained from^(13)C-NMR analysis characterization,FTIR analysis characterization,X-ray diffraction XRD and XPS analysis characterization.It can be observed from characterization data and molecular structure models that the structure of SDV and SDI is dominated by aromatic hydrocarbon,with aromaticity of SDI higher than that of SDV;SDV mainly consists of small molecule basic structure unit,while SDI is largely made from macromolecular structure unit.Based on bond-level parameters of the molecular model,the research found through the autoclave experiment that vitrinite liquefaction process goes under thermodynamics control and inertinite liquefaction process under dynamics control.The research developed an efficient directional direct coal liquefaction technology based on the maceral characteristics of Shenhua coal,which can effectively improve oil yield and lower gas yield.展开更多
DCLR-P was prepared by direct coal liquefaction residue (DCLR) with ash removal.In the present experiments,mesocarbon microbeads (MCMBs) were prepared by co-carbonization of coal tar pitch (CTP) and DCLR-P.With the in...DCLR-P was prepared by direct coal liquefaction residue (DCLR) with ash removal.In the present experiments,mesocarbon microbeads (MCMBs) were prepared by co-carbonization of coal tar pitch (CTP) and DCLR-P.With the increase of DCLR-P content,the yield of MCMBs increased from 47.8% to 56.8%.At the same time,the particle sizes distribution of MCMBs was narrowed,resulting in the decrease of D9o/D10 ratio from 154.88 to 6.53.The results showed that DCLR-P had a positive effect on the preparation of MCMBs.1H-NMR,FTIR,SEM and XRD were used to analyze the mechanisms and characteristics of MCMBs prepared by co-carbonization of CTP and DCLR-P.The results showed that the Proton Donor Quality Index (PDQI) of DCLR-P was 13.32,significantly higher than that of CTP (0.83).This indicated that DCLR-P had more naphthenic structure than CTP,which leads to hydrogen transferring in polycondensation reaction.The aliphatic structure of DCLR-P can improve the solubility and fusibility of mesophase,thereby making the structure of MCMBs more structured.The microstructure of the graphitized MCMBs had a substantially parallel carbon layer useful for its electrical performance.The performance of graphitized MCMBs as a negative electrode material for Li-ion batteries was tested.The particle sizes,tap density,specific surface area and initial charge-discharge efficiency of graphitized MCMBs met the requirements of CMB-I in GB/T-24533-2009.However,the initial discharge capacity of graphitized MCMB was only 296.3 mA h g-1 due to the low degree of graphitization of MCMBs.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
The compatibility between direct coal liquefaction residue(DCLR) and five kinds of pure bitumen(Shell-90,SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition...The compatibility between direct coal liquefaction residue(DCLR) and five kinds of pure bitumen(Shell-90,SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition temperatures(T_g), solubility parameters(SP) and SARA(saturates, aromatics, resins, and asphaltenes) fractions of DCLR,five kinds of pure bitumen and their blends(named as DCLR modified bitumen) were measured using the dynamic shear rheometer(DSR), differential scanning calorimetry(DSC), viscosity, and SARA tests, respectively. And the compatibility between DCLR and pure bitumen was characterized with three approaches, viz. the Cole-Cole plot,T_g, and the solubility parameter difference(SPD) method. Since each method has its own working mechanism, the compatibility ranking for the DCLR and five kinds of pure bitumen is slightly different according to the three approaches. However, the difference is pretty close and sometimes can be ignored. The general compatibility ranking decreases in the following order: Shell-90≈SK-90>DM-70≈ZSY-70>KLMY-50, which is affected by the asphaltenes content and the colloid index(I_c) value in the pure bitumen. Pure bitumen with lower asphaltenes content and colloid index(I_c) value has better compatibility with DCLR.展开更多
Gasification of extraction residue(ER) from direct coal liquefaction with pulverized coal is an efficient way for the utilization of carbonaceous wastes, which improve the overall efficiency of direct coal liquefactio...Gasification of extraction residue(ER) from direct coal liquefaction with pulverized coal is an efficient way for the utilization of carbonaceous wastes, which improve the overall efficiency of direct coal liquefaction technology. The discharge characteristics of ER mixing with pulverized coal is important paraments for its gasification process, which is seldom studied in the literature. In this study, the discharge characteristics of the pulverized coal(M1) as well as its mixture with ER(M2) were systematically investigated in an atmospheric pressure partial fluidization silo with different fluidization apparent velocity. It was observed that although M2 is a viscous powder with lower flowability than M1, the mass flow rate of M2 is 65% higher than M1 at the 3.7 mm·s-1apparent gas velocity. M2 exhibits the properties of Geldart A type powder, which improves the mass flow rate and stability of the discharged material. The mass flow rate of both M1 and M2 first increases and then slowly decreases with the increase of apparent gas velocity of the fluidizing air, which means the discharge process of M1 and M2 can be optimized by the apparent gas velocity.展开更多
To reasonably utilize the coal direct liquefaction residue(DLR), contrasting research on the co-pyrolysis between different low-rank coals and DLR was investigated using a TGA coupled with an FT-IR spectrophotometer a...To reasonably utilize the coal direct liquefaction residue(DLR), contrasting research on the co-pyrolysis between different low-rank coals and DLR was investigated using a TGA coupled with an FT-IR spectrophotometer and a fixed-bed reactor. GC–MS, FTIR, and XRD were used to explore the reaction mechanisms of the various co-pyrolysis processes. Based on the TGA results, it was confirmed that the tetrahydrofuran insoluble fraction of DLR helped to catalyze the conversion reaction of lignite. Also, the addition of DLR improved the yield of tar in the fixed-bed, with altering the composition of the tar. Moreover, a kinetic analysis during the co-pyrolysis was conducted using a distributed activation energy model. The co-pyrolysis reactions showed an approximate double-Gaussian distribution.展开更多
The production capacity of indirect coal liquefaction(ICL)in use in China has reached a level of 8 million t/a,which corresponds to a carbon footprint of>60 million t/a.ICL is facing mountainous pressure to reduce ...The production capacity of indirect coal liquefaction(ICL)in use in China has reached a level of 8 million t/a,which corresponds to a carbon footprint of>60 million t/a.ICL is facing mountainous pressure to reduce its carbon emissions when its development is planned with carbon neutrality as a background objective.This paper studies the pathways that can lead to carbon neutrality for ICL in China,constructing four carbon-neutral pathways for ICL systems with the introduction of green hydrogen,biomass as feedstock and with CCS(carbon capture and storage),which can reduce significant carbon emissions from coal-gasification and water-gas shift processes.The carbon-neutral biomass is used to replace some coal as co-feed to gasification and combustion,leading to reduced carbon emissions as well.Calculations and economic analyses are performed on different carbon-reduction pathways using a carbon-neutral ICL system on a 1 million t/a scale as an example.The results are that the pathway of direct coal substitution with biomass is the lowest carbon-reduction route at RMB 31-125/t CO_(2),substitution with green hydrogen costs the highest at RMB 84-422/t CO_(2) and CCS costs are in the middle at RMB 96-148/t CO_(2).Each pathway has its pros and cons,and a combination of the three may be used for the best outcome.Furthermore,a comprehensive study and systematic summation of the critical technological processes and their underlying challenges for carbon-neutral ICL together with direction for a technological breakthrough are presented.These ICL carbon-reduction pathways presented in this paper are capable of realizing an integrated development between fossil and renewable energy sources,helping the carbon-intense coal-chemical industries to achieve their goals of carbon peak and carbon neutrality.展开更多
Diesel from direct coal liquefaction(DDCL) is a new type of engine alternative energy. But its hydrocarbon composition and physicochemical properties are quite different from those of Petro diesel. In this study, a pr...Diesel from direct coal liquefaction(DDCL) is a new type of engine alternative energy. But its hydrocarbon composition and physicochemical properties are quite different from those of Petro diesel. In this study, a premixed constant volume combustion chamber(CVCC) system with soot particle sampling devices was built. The soot particles in the spray flame were sampled and photographed by thermophoresis probe and transmission electron microscope(TEM). An automatic processing code based on Matlab software was developed to process the TEM images and extract the micro morphology parameters of the soot particles. This study has systematically studied the effects of sampling location, injection pressure, ambient density and oxygen concentration on the micro morphology of soot particles. The ambient density refers to the initial gas density in the CVCC. The results showed that various morphologies and sizes of soot particles coexisted in the upstream of the spray flame. During the evolution of soot particles from upstream to downstream in the flame, the size of soot aggregates gradually decreased, while the maturity of soot aggregates increased. With the increase of injection pressure, ambient density and oxygen concentration, the average sizes of soot aggregates and primary soot particles decreased, but the fractal dimensions of soot aggregates increased gradually. Under the same combustion condition and in-flame sampling location, the average projection area, gyration radius and primary soot diameter of soot aggregates produced by DDCL were significantly lower than those of Petro diesel. The structure of soot particles from DDCL was more compact than that of Petro diesel.展开更多
Radicals are important intermediates in direct coal liquefaction.Certain radicals can cause the cleavage of chemical bonds.At high temperatures,radical fragments can be produced by the splitting of large organic molec...Radicals are important intermediates in direct coal liquefaction.Certain radicals can cause the cleavage of chemical bonds.At high temperatures,radical fragments can be produced by the splitting of large organic molecules,which can break strong chemical bonds through the induction pyrolysis of radicals.The reaction between the formation and annihilation of coal radical fragments and the effect of hydrogen-donor solvents on the radical fragments are discussed in lignite hydrogenolysis.Using the hydroxyl and ether bonds as indicators,the effects of different radicals on the cleavage of chemical bond were investigated employing density functional theory calculations and lignite hydrogenolysis experiments.Results showed that the adjustment of the coal radical fragments could be made by the addition of hydrogendonor solvents.Results showed that the transition from coal radical fragment to H radical leads to the variation of product distribution.The synergistic mechanism of hydrogen supply and hydrogenolysis of hydrogen-donor solvent was proposed.展开更多
Utilizing the extraction residue(ER)of direct coal liquefaction residue as a gasification feedstock has significant economic value.But the characteristic of high ash and iron in the ER would increase the risk of corro...Utilizing the extraction residue(ER)of direct coal liquefaction residue as a gasification feedstock has significant economic value.But the characteristic of high ash and iron in the ER would increase the risk of corrosion of the refractory materials and affect the long-term operation of the gasifier.In this work,corrosion experiments of molten slag derived from a mixture of 20 wt%ER and 80 wt%coal on a high-chromia refractory brick and SiC brick were carried out using a rotary-drum furnace in a simulated gasification atmosphere.The experimental results show that the viscosity of the poured slag is larger as compared to the initial ash sample at the same temperature,which suggests that the viscosity-temperature relationship of the poured slag should be used as the reference for the operation temperature of the gasifier to ensure that the slag can flow during operation.For a high-chromia refractory brick,iron oxides in molten slag could react with Cr_(2)O_(3) in the refractory matrix but,because the aggregate was not found to be damaged,the damage to the matrix structure was the key factor for causing the corrosion of the high-chromia refractory brick.Metallic iron was observed in the exposed SiC brick,which indicated that the reaction between the iron oxides in the slag and SiC occurred,forming metallic iron and SiO_(2).The corrosion of a SiC brick by molten slag depended mainly on the dissolution of Al_(2)O_(3) particles and the reaction between iron oxides in the molten slag and SiC particles.Therefore,the high iron content in coal ash had a serious influence on the corrosion of refractory materials.More efforts need to be made on coal blended with ER as a gasification feedstock in the future.展开更多
Oil-coal slurry prepared in coal direct liquefaction is a dispersed solid-liquid suspension system. In this paper, some factors such as solvent properties, solid concentrations and temperatures, which affect viscosity...Oil-coal slurry prepared in coal direct liquefaction is a dispersed solid-liquid suspension system. In this paper, some factors such as solvent properties, solid concentrations and temperatures, which affect viscosity change of oil-coal slurry, were studied. The viscosity of coal slurry was measured using rotary viscometer, and the rheological properties have been investigated. The viscosity and rheological curves were plotted and regressed, respectively. The results show that the coal slurry behaves a pseudoplastic and thixotropic property. The rheological type of coal slurry was ascertained and its rheological equations were educed. The oil-coal slurry changes to non-Newtonian fluid from Newtonian fluid with the increasing of solid concentration.展开更多
We report the results from systematic studies of Shengli lignite coal-solvent slurries. Solvent type, temperature, coal to solvent ratio, particle granularity, shear rate and shear time were investigated. The viscosit...We report the results from systematic studies of Shengli lignite coal-solvent slurries. Solvent type, temperature, coal to solvent ratio, particle granularity, shear rate and shear time were investigated. The viscosity of the solvents is time independent. However, the slurries are thixotropic. A change from pseudo-plastic to Newtonian behavior occurs as the temperature, or as the solvent to coal ratio, increases. The solvent used in the slurry affects the point at which the rheology changes from pseudo-plastic to Newtonian. The REC slurry changes at 1:1.2 coal to solvent ratio and at 40 °C. The HAR slurry changes at a 1:1.5 ratio and at 60 °C. The rheology of the slurries is pseudo-plastic at low shear rates but Newtonian at high shear rates.展开更多
The composition of coal-derived light oil (IBP-220℃) was separated into 5 fractions by atmospheric distillation and analyzed by gas chromatography/mass spec- trometry (GC/MS).The light oil was made at 0.1 t/d coal di...The composition of coal-derived light oil (IBP-220℃) was separated into 5 fractions by atmospheric distillation and analyzed by gas chromatography/mass spec- trometry (GC/MS).The light oil was made at 0.1 t/d coal direct liquefaction bench scale unit (BSU) at China Coal Research Institute (CCRI).Six groups of organics,including acyclic hydrocarbon,alicyclic hydrocarbon,aromatics,phenols,polynuclear aromatics and heterocyclics,were found and 80 compounds were tentatively identified in total.Alicyclic hydrocarbon is the main component of the light oil compared to other groups whether in relative mass percentage or the number of compounds in group.The predominant oxy- gen-contained compound is phenols,and the nitrogen-containing compound is pyridine. No sulfur-containing compound is detected.展开更多
基金the financial support from the National Key Research and Development Program of China(2022YFB4101302-01)the National Natural Science Foundation of China(22178243)the science and technology innovation project of China Shenhua Coal to Liquid and Chemical Company Limited(MZYHG-22–02).
文摘The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.
基金Supported by the National Engineering Labo-ratory of Direct Coal Liquefaction(MZY-16).
文摘In this research,molecular structure models were developed respectively for Shenhua coal vitrinite concentrates(SDV)and inertinite concentrates(SDI),on the basis of information on constitutional unit of Shenhau coal and elemental analysis results obtained from^(13)C-NMR analysis characterization,FTIR analysis characterization,X-ray diffraction XRD and XPS analysis characterization.It can be observed from characterization data and molecular structure models that the structure of SDV and SDI is dominated by aromatic hydrocarbon,with aromaticity of SDI higher than that of SDV;SDV mainly consists of small molecule basic structure unit,while SDI is largely made from macromolecular structure unit.Based on bond-level parameters of the molecular model,the research found through the autoclave experiment that vitrinite liquefaction process goes under thermodynamics control and inertinite liquefaction process under dynamics control.The research developed an efficient directional direct coal liquefaction technology based on the maceral characteristics of Shenhua coal,which can effectively improve oil yield and lower gas yield.
基金Supported by National Key Research and Development Program of China(2018YFB0604601)and the Technology Innovation Fund of China coal research institute(2016CX01).
文摘DCLR-P was prepared by direct coal liquefaction residue (DCLR) with ash removal.In the present experiments,mesocarbon microbeads (MCMBs) were prepared by co-carbonization of coal tar pitch (CTP) and DCLR-P.With the increase of DCLR-P content,the yield of MCMBs increased from 47.8% to 56.8%.At the same time,the particle sizes distribution of MCMBs was narrowed,resulting in the decrease of D9o/D10 ratio from 154.88 to 6.53.The results showed that DCLR-P had a positive effect on the preparation of MCMBs.1H-NMR,FTIR,SEM and XRD were used to analyze the mechanisms and characteristics of MCMBs prepared by co-carbonization of CTP and DCLR-P.The results showed that the Proton Donor Quality Index (PDQI) of DCLR-P was 13.32,significantly higher than that of CTP (0.83).This indicated that DCLR-P had more naphthenic structure than CTP,which leads to hydrogen transferring in polycondensation reaction.The aliphatic structure of DCLR-P can improve the solubility and fusibility of mesophase,thereby making the structure of MCMBs more structured.The microstructure of the graphitized MCMBs had a substantially parallel carbon layer useful for its electrical performance.The performance of graphitized MCMBs as a negative electrode material for Li-ion batteries was tested.The particle sizes,tap density,specific surface area and initial charge-discharge efficiency of graphitized MCMBs met the requirements of CMB-I in GB/T-24533-2009.However,the initial discharge capacity of graphitized MCMB was only 296.3 mA h g-1 due to the low degree of graphitization of MCMBs.
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sponsored by the National Natural Science Foundation of China (51478028 and 51778038)the Program for Changjiang Scholars and Innovative Research Team in Universities(IRT-17R06)
文摘The compatibility between direct coal liquefaction residue(DCLR) and five kinds of pure bitumen(Shell-90,SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition temperatures(T_g), solubility parameters(SP) and SARA(saturates, aromatics, resins, and asphaltenes) fractions of DCLR,five kinds of pure bitumen and their blends(named as DCLR modified bitumen) were measured using the dynamic shear rheometer(DSR), differential scanning calorimetry(DSC), viscosity, and SARA tests, respectively. And the compatibility between DCLR and pure bitumen was characterized with three approaches, viz. the Cole-Cole plot,T_g, and the solubility parameter difference(SPD) method. Since each method has its own working mechanism, the compatibility ranking for the DCLR and five kinds of pure bitumen is slightly different according to the three approaches. However, the difference is pretty close and sometimes can be ignored. The general compatibility ranking decreases in the following order: Shell-90≈SK-90>DM-70≈ZSY-70>KLMY-50, which is affected by the asphaltenes content and the colloid index(I_c) value in the pure bitumen. Pure bitumen with lower asphaltenes content and colloid index(I_c) value has better compatibility with DCLR.
文摘Gasification of extraction residue(ER) from direct coal liquefaction with pulverized coal is an efficient way for the utilization of carbonaceous wastes, which improve the overall efficiency of direct coal liquefaction technology. The discharge characteristics of ER mixing with pulverized coal is important paraments for its gasification process, which is seldom studied in the literature. In this study, the discharge characteristics of the pulverized coal(M1) as well as its mixture with ER(M2) were systematically investigated in an atmospheric pressure partial fluidization silo with different fluidization apparent velocity. It was observed that although M2 is a viscous powder with lower flowability than M1, the mass flow rate of M2 is 65% higher than M1 at the 3.7 mm·s-1apparent gas velocity. M2 exhibits the properties of Geldart A type powder, which improves the mass flow rate and stability of the discharged material. The mass flow rate of both M1 and M2 first increases and then slowly decreases with the increase of apparent gas velocity of the fluidizing air, which means the discharge process of M1 and M2 can be optimized by the apparent gas velocity.
基金Supported by National High-tech Research and Development Program of China(2011AA05A2021)the National Natural Science Foundation of China(21536009)Science and Technology Plan Projects of Shaanxi Province(2017ZDCXL-GY-10-03).
文摘To reasonably utilize the coal direct liquefaction residue(DLR), contrasting research on the co-pyrolysis between different low-rank coals and DLR was investigated using a TGA coupled with an FT-IR spectrophotometer and a fixed-bed reactor. GC–MS, FTIR, and XRD were used to explore the reaction mechanisms of the various co-pyrolysis processes. Based on the TGA results, it was confirmed that the tetrahydrofuran insoluble fraction of DLR helped to catalyze the conversion reaction of lignite. Also, the addition of DLR improved the yield of tar in the fixed-bed, with altering the composition of the tar. Moreover, a kinetic analysis during the co-pyrolysis was conducted using a distributed activation energy model. The co-pyrolysis reactions showed an approximate double-Gaussian distribution.
文摘The production capacity of indirect coal liquefaction(ICL)in use in China has reached a level of 8 million t/a,which corresponds to a carbon footprint of>60 million t/a.ICL is facing mountainous pressure to reduce its carbon emissions when its development is planned with carbon neutrality as a background objective.This paper studies the pathways that can lead to carbon neutrality for ICL in China,constructing four carbon-neutral pathways for ICL systems with the introduction of green hydrogen,biomass as feedstock and with CCS(carbon capture and storage),which can reduce significant carbon emissions from coal-gasification and water-gas shift processes.The carbon-neutral biomass is used to replace some coal as co-feed to gasification and combustion,leading to reduced carbon emissions as well.Calculations and economic analyses are performed on different carbon-reduction pathways using a carbon-neutral ICL system on a 1 million t/a scale as an example.The results are that the pathway of direct coal substitution with biomass is the lowest carbon-reduction route at RMB 31-125/t CO_(2),substitution with green hydrogen costs the highest at RMB 84-422/t CO_(2) and CCS costs are in the middle at RMB 96-148/t CO_(2).Each pathway has its pros and cons,and a combination of the three may be used for the best outcome.Furthermore,a comprehensive study and systematic summation of the critical technological processes and their underlying challenges for carbon-neutral ICL together with direction for a technological breakthrough are presented.These ICL carbon-reduction pathways presented in this paper are capable of realizing an integrated development between fossil and renewable energy sources,helping the carbon-intense coal-chemical industries to achieve their goals of carbon peak and carbon neutrality.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFE0130800)National Natural Science Foundation of China(Grant No.91741122)。
文摘Diesel from direct coal liquefaction(DDCL) is a new type of engine alternative energy. But its hydrocarbon composition and physicochemical properties are quite different from those of Petro diesel. In this study, a premixed constant volume combustion chamber(CVCC) system with soot particle sampling devices was built. The soot particles in the spray flame were sampled and photographed by thermophoresis probe and transmission electron microscope(TEM). An automatic processing code based on Matlab software was developed to process the TEM images and extract the micro morphology parameters of the soot particles. This study has systematically studied the effects of sampling location, injection pressure, ambient density and oxygen concentration on the micro morphology of soot particles. The ambient density refers to the initial gas density in the CVCC. The results showed that various morphologies and sizes of soot particles coexisted in the upstream of the spray flame. During the evolution of soot particles from upstream to downstream in the flame, the size of soot aggregates gradually decreased, while the maturity of soot aggregates increased. With the increase of injection pressure, ambient density and oxygen concentration, the average sizes of soot aggregates and primary soot particles decreased, but the fractal dimensions of soot aggregates increased gradually. Under the same combustion condition and in-flame sampling location, the average projection area, gyration radius and primary soot diameter of soot aggregates produced by DDCL were significantly lower than those of Petro diesel. The structure of soot particles from DDCL was more compact than that of Petro diesel.
基金The authors are grateful to the National Natural Science Foundation of China(Grant No.22038008)the 2030 Major Project Pilot Project from CHN Energy,China(Grant No.GJNY2030XDXM-19-13,2)for the financial suppor。
文摘Radicals are important intermediates in direct coal liquefaction.Certain radicals can cause the cleavage of chemical bonds.At high temperatures,radical fragments can be produced by the splitting of large organic molecules,which can break strong chemical bonds through the induction pyrolysis of radicals.The reaction between the formation and annihilation of coal radical fragments and the effect of hydrogen-donor solvents on the radical fragments are discussed in lignite hydrogenolysis.Using the hydroxyl and ether bonds as indicators,the effects of different radicals on the cleavage of chemical bond were investigated employing density functional theory calculations and lignite hydrogenolysis experiments.Results showed that the adjustment of the coal radical fragments could be made by the addition of hydrogendonor solvents.Results showed that the transition from coal radical fragment to H radical leads to the variation of product distribution.The synergistic mechanism of hydrogen supply and hydrogenolysis of hydrogen-donor solvent was proposed.
基金This work was supported by the Science and Technology Innovation Project of CHN Energy(grant number GJNY-21-91)the Science and Technology Innovation Project of CHN Energy(grant number GJNY-20-119)the National Key R&D program of China(grant number 2017YFB0602603).
文摘Utilizing the extraction residue(ER)of direct coal liquefaction residue as a gasification feedstock has significant economic value.But the characteristic of high ash and iron in the ER would increase the risk of corrosion of the refractory materials and affect the long-term operation of the gasifier.In this work,corrosion experiments of molten slag derived from a mixture of 20 wt%ER and 80 wt%coal on a high-chromia refractory brick and SiC brick were carried out using a rotary-drum furnace in a simulated gasification atmosphere.The experimental results show that the viscosity of the poured slag is larger as compared to the initial ash sample at the same temperature,which suggests that the viscosity-temperature relationship of the poured slag should be used as the reference for the operation temperature of the gasifier to ensure that the slag can flow during operation.For a high-chromia refractory brick,iron oxides in molten slag could react with Cr_(2)O_(3) in the refractory matrix but,because the aggregate was not found to be damaged,the damage to the matrix structure was the key factor for causing the corrosion of the high-chromia refractory brick.Metallic iron was observed in the exposed SiC brick,which indicated that the reaction between the iron oxides in the slag and SiC occurred,forming metallic iron and SiO_(2).The corrosion of a SiC brick by molten slag depended mainly on the dissolution of Al_(2)O_(3) particles and the reaction between iron oxides in the molten slag and SiC particles.Therefore,the high iron content in coal ash had a serious influence on the corrosion of refractory materials.More efforts need to be made on coal blended with ER as a gasification feedstock in the future.
基金Project 2004CB217601 supported by the National Key Basic Research Development Plan (973) of China
文摘Oil-coal slurry prepared in coal direct liquefaction is a dispersed solid-liquid suspension system. In this paper, some factors such as solvent properties, solid concentrations and temperatures, which affect viscosity change of oil-coal slurry, were studied. The viscosity of coal slurry was measured using rotary viscometer, and the rheological properties have been investigated. The viscosity and rheological curves were plotted and regressed, respectively. The results show that the coal slurry behaves a pseudoplastic and thixotropic property. The rheological type of coal slurry was ascertained and its rheological equations were educed. The oil-coal slurry changes to non-Newtonian fluid from Newtonian fluid with the increasing of solid concentration.
基金Project 2004CB217601 supported by the National Basic Research Program of China
文摘We report the results from systematic studies of Shengli lignite coal-solvent slurries. Solvent type, temperature, coal to solvent ratio, particle granularity, shear rate and shear time were investigated. The viscosity of the solvents is time independent. However, the slurries are thixotropic. A change from pseudo-plastic to Newtonian behavior occurs as the temperature, or as the solvent to coal ratio, increases. The solvent used in the slurry affects the point at which the rheology changes from pseudo-plastic to Newtonian. The REC slurry changes at 1:1.2 coal to solvent ratio and at 40 °C. The HAR slurry changes at a 1:1.5 ratio and at 60 °C. The rheology of the slurries is pseudo-plastic at low shear rates but Newtonian at high shear rates.
基金the National Basic Reserch Program of China(2004CB217605)
文摘The composition of coal-derived light oil (IBP-220℃) was separated into 5 fractions by atmospheric distillation and analyzed by gas chromatography/mass spec- trometry (GC/MS).The light oil was made at 0.1 t/d coal direct liquefaction bench scale unit (BSU) at China Coal Research Institute (CCRI).Six groups of organics,including acyclic hydrocarbon,alicyclic hydrocarbon,aromatics,phenols,polynuclear aromatics and heterocyclics,were found and 80 compounds were tentatively identified in total.Alicyclic hydrocarbon is the main component of the light oil compared to other groups whether in relative mass percentage or the number of compounds in group.The predominant oxy- gen-contained compound is phenols,and the nitrogen-containing compound is pyridine. No sulfur-containing compound is detected.