Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature operation.However,the membrane performance was strongly limited by the trade-...Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature operation.However,the membrane performance was strongly limited by the trade-off between permeance and selectivity.Herein,novel 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)-2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(APAF)-5-amino-2-(4-aminobenzene)benzimidazole(BIA)asymmetric membranes with a thickness of 300 nm were successfully prepared by the non-solvent induced phase separation method.The membrane performance was modulated by regulating dope solution compositions(e.g.,tetrahydrofuran and polymer concentration).The ideal He/CH_(4) selectivity was 124 and the optimized He permeance reached 87 GPU,beyond the current upper bound.He/CH_(4) selectivity was 75 and He permeance was 73 GPU for the binary mixture feed containing 0.2 mol%He.The membrane showed good resistance to CO_(2) and C_(2)H_(6),which are the typical impurities in natural gas.The 6FDA-APAF-BIA membranes have good stability(>160 h),which can provide great potential in He extraction from natural gas.展开更多
The separation of He/H_(2)using membrane technology has gained significant interest in the field of He extraction from natural gas.One of the greatest challenges associated with this process is the extremely close kin...The separation of He/H_(2)using membrane technology has gained significant interest in the field of He extraction from natural gas.One of the greatest challenges associated with this process is the extremely close kinetic diameters of the two gas molecules,resulting in low membrane selectivity.In this study,we investigated the structure-performance relationship of metal-organic framework(MOF)membranes for He/H_(2)separation through molecular simulations and machine learning approaches.By conducting molecular simulations,we identified the potential MOF membranes with high separation performance from the Computation-Ready Experimental(Co RE)MOF database,and the diffusion-dominated mechanism was further elucidated.Moreover,random forest(RF)-based machine learning models were established to identify the crucial factors influencing the He/H_(2)separation performance of MOF membranes.The pore limiting diameter(PLD)and void fraction(φ),are revealed as the most important physical features for determining the membrane selectivity and He permeability,respectively.Additionally,density functional theory(DFT)calculations were carried out to validate the molecular simulation results and suggested that the electronegative atoms on the pore surfaces can enhance the diffusion-based separation of He/H_(2),which is critical for improving the membrane selectivities of He/H_(2).This study offers useful insights for designing and developing novel MOF membranes for the separation of He/H_(2)at the molecular level.展开更多
Helium(He)is commercially produced from natural gas by low-temperature condensation.The process is energy extensive because of the extremely low He concentration(<0.3%)and the operation at cryogenic temperature.Her...Helium(He)is commercially produced from natural gas by low-temperature condensation.The process is energy extensive because of the extremely low He concentration(<0.3%)and the operation at cryogenic temperature.Herein we demonstrated DD3R zeolite membrane was efficient to extract He from natural gas at atmosphere temperature.The membrane performance was evaluated in terms of temperature,pressure and molar fractions.The overall membrane performance was dominated by the diffusivity selectivity.The single He permeance and ideal He/CH_(4) selectivity were 5.8×10^(-9)mol·m^(-2)·s^(-1)·Pa^(-1)and 79 under a feed pressure of 1.3 MPa.Even though He concentration was as low as 0.22%,the He permeance and He/CH_(4) mixture selectivity were 3.0×10^(-9)mol·m^(-2)·s^(-1)·Pa^(-1)and 44 at 0.7 MPa.During the longterm operation(~130 h)the membrane performance was stable even the feed mixture containing3.6%ethane as contaminations.The results approved the feasibility of DD3R zeolite membranes for He extraction from natural gas.展开更多
基金sponsored by the National Key Research and Development Program of China(Grant No.2021YFC2101203)the National Natural Science Foundation of China(Grant Nos.22178164 and U22B20148)+2 种基金the Jiangsu Provincial Carbon Peak Carbon Neutral Science and Technology Innovation Special Fund(Grant No.BE2022033)the Jiangsu Specially-Appointed Professors Programthe State Key Laboratory of Materials-Oriented Chemical Engineering(Grant No.ZK202002).
文摘Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature operation.However,the membrane performance was strongly limited by the trade-off between permeance and selectivity.Herein,novel 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)-2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(APAF)-5-amino-2-(4-aminobenzene)benzimidazole(BIA)asymmetric membranes with a thickness of 300 nm were successfully prepared by the non-solvent induced phase separation method.The membrane performance was modulated by regulating dope solution compositions(e.g.,tetrahydrofuran and polymer concentration).The ideal He/CH_(4) selectivity was 124 and the optimized He permeance reached 87 GPU,beyond the current upper bound.He/CH_(4) selectivity was 75 and He permeance was 73 GPU for the binary mixture feed containing 0.2 mol%He.The membrane showed good resistance to CO_(2) and C_(2)H_(6),which are the typical impurities in natural gas.The 6FDA-APAF-BIA membranes have good stability(>160 h),which can provide great potential in He extraction from natural gas.
基金supported by the National Natural Science Foundation of China(Nos.22141001 and 22108202)
文摘The separation of He/H_(2)using membrane technology has gained significant interest in the field of He extraction from natural gas.One of the greatest challenges associated with this process is the extremely close kinetic diameters of the two gas molecules,resulting in low membrane selectivity.In this study,we investigated the structure-performance relationship of metal-organic framework(MOF)membranes for He/H_(2)separation through molecular simulations and machine learning approaches.By conducting molecular simulations,we identified the potential MOF membranes with high separation performance from the Computation-Ready Experimental(Co RE)MOF database,and the diffusion-dominated mechanism was further elucidated.Moreover,random forest(RF)-based machine learning models were established to identify the crucial factors influencing the He/H_(2)separation performance of MOF membranes.The pore limiting diameter(PLD)and void fraction(φ),are revealed as the most important physical features for determining the membrane selectivity and He permeability,respectively.Additionally,density functional theory(DFT)calculations were carried out to validate the molecular simulation results and suggested that the electronegative atoms on the pore surfaces can enhance the diffusion-based separation of He/H_(2),which is critical for improving the membrane selectivities of He/H_(2).This study offers useful insights for designing and developing novel MOF membranes for the separation of He/H_(2)at the molecular level.
基金sponsored by the National Natural Science Foundation of China(21908097,22035002)the National Key Research and Development Program of China(2021YFC2101203)+1 种基金Jiangsu Specially-Appointed Professors Program and"333 Talent Project"of Jiangsu ProvinceState Key Laboratory of Materials-Oriented Chemical Engineering(ZK202002)。
文摘Helium(He)is commercially produced from natural gas by low-temperature condensation.The process is energy extensive because of the extremely low He concentration(<0.3%)and the operation at cryogenic temperature.Herein we demonstrated DD3R zeolite membrane was efficient to extract He from natural gas at atmosphere temperature.The membrane performance was evaluated in terms of temperature,pressure and molar fractions.The overall membrane performance was dominated by the diffusivity selectivity.The single He permeance and ideal He/CH_(4) selectivity were 5.8×10^(-9)mol·m^(-2)·s^(-1)·Pa^(-1)and 79 under a feed pressure of 1.3 MPa.Even though He concentration was as low as 0.22%,the He permeance and He/CH_(4) mixture selectivity were 3.0×10^(-9)mol·m^(-2)·s^(-1)·Pa^(-1)and 44 at 0.7 MPa.During the longterm operation(~130 h)the membrane performance was stable even the feed mixture containing3.6%ethane as contaminations.The results approved the feasibility of DD3R zeolite membranes for He extraction from natural gas.
