In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream proces...In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream processes.This study developed a coupled process of biomass chemical looping H2 production and reductive calcination of CaCO_(3).Firstly,a mass and energy balance of the coupled process was established in Aspen Plus.Following this,process optimization and energy integration were implemented to provide optimized operation conditions.Lastly,a life cycle assessment was carried out to assess the carbon footprint of the coupled process.Results reveal that the decomposition temperature of CaCO_(3)in an H_(2)atmosphere can be reduced to 780℃(generally around 900℃),and the conversion of CO_(2)from CaCO_(3)decomposition reached 81.33%with an H2:CO ratio of 2.49 in gaseous products.By optimizing systemic energy through heat integration,an energy efficiency of 86.30%was achieved.Additionally,the carbon footprint analysis revealed that the process with energy integration had a low global warming potential(GWP)of-2.624 kg·kg^(-1)(CO_(2)/CaO).Conclusively,this work performed a systematic analysis of introducing biomass-derived H_(2)into CaCO_(3)calcination and demonstrated the positive role of reductive calcination using green H_(2)in mitigating CO_(2)emissions within the carbonate industry.展开更多
The chemical looping process,where an oxygen carrier is reduced and oxidized in a cyclic manner,offers a promising option for hydrogen production through splitting water because of the much higher water splitting effi...The chemical looping process,where an oxygen carrier is reduced and oxidized in a cyclic manner,offers a promising option for hydrogen production through splitting water because of the much higher water splitting efficiency than solar electrocatalytic and photocatalytic process.A typical oxygen carrier has to comprise a significant amount of inert support,to maintain stability in multiple redox cycles,thereby resulting in a trade-off between the reaction reactivity and stability.Herein,we proposed the use of ion-conductive yttria-stabilized zirconia(YSZ)support Fe_(2)O_(3)to prepare oxygen carriers materials.The obtained Fe_(2)O_(3)/YSZ composites showed high reactivity and stability.Particularly,Fe_(2)O_(3)/YSZ-20(oxygen storage capacity,24.13%)exhibited high hydrogen yield of~10.30 mmol g^(-1) and hydrogen production rate of~0.66 mmol g^(-1) min^(-1) which was twice as high as that of Fe_(2)O_(3)/Al_(2)O_(3).Further,the transient pulse test indicated that active oxygen diffusion was the ratelimiting step during the redox process.The electrochemical impedance spectroscopy(EIS)measurement revealed that the YSZ support addition facilitated oxygen diffusion of materials,which contributed to the improved hydrogen production performance.The support effect obtained in this work provides a potentially efficient route for the modification of oxygen carrier materials.展开更多
Operating chemical looping process at mid-temperatures(550–750℃)presents exciting potential for the stable production of hydrogen.However,the reactivity of oxygen carriers is compromised by the detrimental effect of...Operating chemical looping process at mid-temperatures(550–750℃)presents exciting potential for the stable production of hydrogen.However,the reactivity of oxygen carriers is compromised by the detrimental effect of the relatively low temperatures on the redox kinetics.Although the reactivity at mid-temperature can be improved by the addition of noble metals,the high cost of these noble metal containing materials significantly hindered their scalable applications.In the current work,we propose to incorporate earth-abundant metals into the ironbased spinel for hydrogen production in a chemical looping scheme at mid-temperatures.Mn0.2Co0.4Fe2.4O4 shows a high hydrogen production performance at the average rate of~0.62 mmol g^(-1) min^(-1) and a hydrogen yield of~9.29 mmol g^(-1) with satisfactory stability over 20 cycles at 550℃.The mechanism studies manifest that the enhanced hydrogen production performance is a result of the improved oxygen-ion conductivity to enhance reduction reaction and high reactivity of reduced samples with steam.The performance of the oxygen carriers in this work is comparable to those noble-metal containing materials,enabling their potential for industrial applications.展开更多
Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an ...Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an intermediate carrier for hydrogen supplies,providing hydrogen energy through instant methanol conversion.In this study,a sorption-enhanced,chemical-looping,oxidative steam methanol-reforming(SECLOSRM)process is proposed using CuO–MgO for the on-board hydrogen supply,which could be a promising method for safe and efficient hydrogen production.Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process.The effects of CuO/CH_(3)OH,MgO/CH_(3)OH,and H_(2)O/CH_(3)OH mole ratios and of temperature on H_(2)production rate,H utilization efficiency,CH_(3)OH conversion,CO concentration,and system heat balance are discussed thoroughly.The results indicate that the system can be operated in autothermal conditions with high-purity hydrogen(99.50 vol%)and ultra-low-concentration CO(<50 ppm)generation,which confirms the possibility of integrating low-temperature proton-exchange membrane fuel cells(LT-PEFMCs)with the SECL-OSRM process.The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H_(2)O/CH_(3)OH and MgO/CH_(3)OH mole ratios.展开更多
Two Cu-Mo-Fe-Ox samples, which can store and supply pure hydrogen through repeated redox reaction （Fe3O4＋4H23Fe＋4H2O）, were prepared by co-precipitation （FCM-C） and impregnation （FCM-I） methods, respectively, ...Two Cu-Mo-Fe-Ox samples, which can store and supply pure hydrogen through repeated redox reaction （Fe3O4＋4H23Fe＋4H2O）, were prepared by co-precipitation （FCM-C） and impregnation （FCM-I） methods, respectively, and the performance of hydrogen production from water were investigated. Compared with the impregnated sample, the co-precipitation sample presented better catalytic activity. The samples were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM）, X-ray photoelectron spectroscopy （XPS）, Fourier transform infrared spectroscopy （FT-IR） and temperature-programmed reduction （H2-TPR） techniques. XRD, FE-SEM and XPS results suggest that the FCM-C sample has smaller particle size and higher dispersion of iron oxide than that of FCM-I sample. In addition, FT-IR and H2-TPR analyses indicate that the weak interaction among metal oxides in FCM-C sample may induce facile reduction of active metal and superior property of hydrogen production by decomposing water in success展开更多
The chemical looping steam reforming(CLSR)of bioethanol is an energy-efficient and carbon-neutral approach of hydrogen production.This paper describes the use of a Ni_(x)Mg_(1-x)O solid solution as the oxy-gen carrier...The chemical looping steam reforming(CLSR)of bioethanol is an energy-efficient and carbon-neutral approach of hydrogen production.This paper describes the use of a Ni_(x)Mg_(1-x)O solid solution as the oxy-gen carrier(OC)in the CLSR of bioethanol.Due to the regulation effect of Mg^(2+)in Ni_(x)Mg_(1-x)O,a three-stage reaction mechanism of the CLSR process is proposed.The surface oxygen of Ni_(x)Mg_(1-x)O initially causes complete oxidation of the ethanol.Subsequently,H_(2)O and bulk oxygen confined by Mg^(2+)react with etha-nol to form CH_(3)COO^(*)followed by H_(2) over partially reduced Ni_(x)Mg_(1-x)O.Once the bulk oxygen is con-sumed,the ethanol steam reforming process is promoted by the metallic nickel in the stage Ⅲ.As a result,Ni_(0.4)Mg_(0.6)O exhibits a high H_(2) selectivity(4.72 mol H_(2) per mole ethanol)with a low steam-to-carbon molar ratio of 1,and remains stable over 30 CLSR cycles.The design of this solid-solution OC pro-vides a versatile strategy for manipulating the chemical looping process.展开更多
Hydrogen is an attractive energy carrier due to the high conversion efficiency and low pollutant emission.Chemical looping hydrogen production(CLHP)is an available way for producing high purity hydrogen with relativel...Hydrogen is an attractive energy carrier due to the high conversion efficiency and low pollutant emission.Chemical looping hydrogen production(CLHP)is an available way for producing high purity hydrogen with relatively low penalty energy and CO_(2)is captured simultaneously.Three reactors are usually contained for CLHP system including air reactor(AR),fuel reactor(FR)and steam reactor(SR).In current work,we focus on the performance of CLHP system,which is the basement for operation and design.Numerical simulations are carried out for analyzing the flow behavior and the numerical structure is built according to the experimental unit constructed at Southeast University,China.Results show that the operation of L-valve influences most the solid circulating rate of system and particles pass L-valve easily with large aeration rate.Mass distribution results indicate that fuel reactor has the capacity for particles storage.Increase of gas inlet rate of steam reactor leads to more particles leave steam reactor and accumulate into fuel reactor.L-valve can prevent the gas leakage between reactors and it will be adopted for reactive unit.Combining the operation of fuel reactor and L-valve,the system can reach steady state and get the regulating ability.展开更多
Hydrogen generation through thermal chemical water splitting technology has recently received in- creasingly international interest in the nuclear hydrogen production field. Besides the main known sulfur-iodine (S-I) ...Hydrogen generation through thermal chemical water splitting technology has recently received in- creasingly international interest in the nuclear hydrogen production field. Besides the main known sulfur-iodine (S-I) cycle developed by the General Atomics Company and the UT3 cycle (iron, calcium, and bromine) developed at the University of Tokyo, the thermal cycle based on metal oxide two-step water splitting methods is also receiving research and development attention worldwide. In this work, copper ferrite was prepared by the co-precipitation method and oxygen-deficient copper ferrite was synthesized through first and second calcination steps for the application of hydrogen production by a two-step water splitting process. The crystal structure, properties, chemical composition and δ were investigated in detail by utilizing X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal analysis (DTA), atomic absorption spectrometer (AAS), ultraviolet spectrophotometry (UV), gas chro- matography (GC), and so on. The experimental two-step thermal chemical cycle reactor for hydrogen generation was designed and developed in this lab. The hydrogen generation process of water splitting through CuFe2O4-δ and the cycle performance of copper ferrite regeneration were firstly studied and discussed.展开更多
Electrochemical water splitting has been demonstrated as a promising technology for the renewable generation of green hydrogen from water.Despite the extensive progress in materials science,one particular challenge fo...Electrochemical water splitting has been demonstrated as a promising technology for the renewable generation of green hydrogen from water.Despite the extensive progress in materials science,one particular challenge for further development towards industrial application lies in the rational design and exploitation of efficient and cost-effective materials,especially oxygen evolution reaction(OER)electrocatalysts at the anode.In addition,attempts to replace the OER with other more oxidizable anode reactions are being evaluated as a groundbreaking strategy for generating hydrogen at lower potentials and reducing overall energy costs while producing valuable chemicals simultaneously.Compared with Fe/Co/Ni-based compounds,Cu-based materials have not received extensive research attention for electrode designs despite their high conductivity and abundant earth reserves.In this review,combining with the advantages of a three-dimensional network structure of metal foams,we summarize recent progress on Cu foam(CF)-derived materials as efficient electrocatalysts towards pure water electrolysis and hybrid water electrolysis.The advantages of CF and design strategies to enhance the electrocatalytic activity and operational durability are presented first.Catalyst design and fabrication strategies are then highlighted and the structure-activity relationship is also discussed.Finally,we propose challenges and perspectives on self-supported electrodes beyond CF-derived materials.展开更多
基金support from the National Natural Science Foundation of China(21978128,91934302)partial support from the State Key Laboratory of Materials-oriented Chemical Engineering(ZK202006)also acknowledged.Additionallysupported by the“Cultivation Program for The Excellent Doctoral Dissertation of Nanjing Tech University(3800124701)”.
文摘In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream processes.This study developed a coupled process of biomass chemical looping H2 production and reductive calcination of CaCO_(3).Firstly,a mass and energy balance of the coupled process was established in Aspen Plus.Following this,process optimization and energy integration were implemented to provide optimized operation conditions.Lastly,a life cycle assessment was carried out to assess the carbon footprint of the coupled process.Results reveal that the decomposition temperature of CaCO_(3)in an H_(2)atmosphere can be reduced to 780℃(generally around 900℃),and the conversion of CO_(2)from CaCO_(3)decomposition reached 81.33%with an H2:CO ratio of 2.49 in gaseous products.By optimizing systemic energy through heat integration,an energy efficiency of 86.30%was achieved.Additionally,the carbon footprint analysis revealed that the process with energy integration had a low global warming potential(GWP)of-2.624 kg·kg^(-1)(CO_(2)/CaO).Conclusively,this work performed a systematic analysis of introducing biomass-derived H_(2)into CaCO_(3)calcination and demonstrated the positive role of reductive calcination using green H_(2)in mitigating CO_(2)emissions within the carbonate industry.
基金the National Natural Science Foundation of China(Grant No.51906041)the Natural Science Foundation of Jiangsu Province(Grant NO.BK20190360)the National Science Foundation for Distinguished Young Scholars of China(Grant No.51525601)。
文摘The chemical looping process,where an oxygen carrier is reduced and oxidized in a cyclic manner,offers a promising option for hydrogen production through splitting water because of the much higher water splitting efficiency than solar electrocatalytic and photocatalytic process.A typical oxygen carrier has to comprise a significant amount of inert support,to maintain stability in multiple redox cycles,thereby resulting in a trade-off between the reaction reactivity and stability.Herein,we proposed the use of ion-conductive yttria-stabilized zirconia(YSZ)support Fe_(2)O_(3)to prepare oxygen carriers materials.The obtained Fe_(2)O_(3)/YSZ composites showed high reactivity and stability.Particularly,Fe_(2)O_(3)/YSZ-20(oxygen storage capacity,24.13%)exhibited high hydrogen yield of~10.30 mmol g^(-1) and hydrogen production rate of~0.66 mmol g^(-1) min^(-1) which was twice as high as that of Fe_(2)O_(3)/Al_(2)O_(3).Further,the transient pulse test indicated that active oxygen diffusion was the ratelimiting step during the redox process.The electrochemical impedance spectroscopy(EIS)measurement revealed that the YSZ support addition facilitated oxygen diffusion of materials,which contributed to the improved hydrogen production performance.The support effect obtained in this work provides a potentially efficient route for the modification of oxygen carrier materials.
基金The authors gratefully acknowledge the National Natural Science Foundation of China(Grant No.51906041)the Natural Science Foundation of Jiangsu Province(Grant NO.BK20190360)the National Science Foundation for Distinguished Young Scholars of China(Grant No.51525601).
文摘Operating chemical looping process at mid-temperatures(550–750℃)presents exciting potential for the stable production of hydrogen.However,the reactivity of oxygen carriers is compromised by the detrimental effect of the relatively low temperatures on the redox kinetics.Although the reactivity at mid-temperature can be improved by the addition of noble metals,the high cost of these noble metal containing materials significantly hindered their scalable applications.In the current work,we propose to incorporate earth-abundant metals into the ironbased spinel for hydrogen production in a chemical looping scheme at mid-temperatures.Mn0.2Co0.4Fe2.4O4 shows a high hydrogen production performance at the average rate of~0.62 mmol g^(-1) min^(-1) and a hydrogen yield of~9.29 mmol g^(-1) with satisfactory stability over 20 cycles at 550℃.The mechanism studies manifest that the enhanced hydrogen production performance is a result of the improved oxygen-ion conductivity to enhance reduction reaction and high reactivity of reduced samples with steam.The performance of the oxygen carriers in this work is comparable to those noble-metal containing materials,enabling their potential for industrial applications.
基金supported by the National Key R&D Program of China(2018YFE0111100)National Natural Science Foundation of China(52106193,21908162)+2 种基金the Natural Science Foundation of Hunan Province(2021JJ40756)the Science and Technology Innovation Program of Hunan Province(2020GK2070)the Innovation-Driven Project of Central South University(2020CX008)
文摘Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an intermediate carrier for hydrogen supplies,providing hydrogen energy through instant methanol conversion.In this study,a sorption-enhanced,chemical-looping,oxidative steam methanol-reforming(SECLOSRM)process is proposed using CuO–MgO for the on-board hydrogen supply,which could be a promising method for safe and efficient hydrogen production.Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process.The effects of CuO/CH_(3)OH,MgO/CH_(3)OH,and H_(2)O/CH_(3)OH mole ratios and of temperature on H_(2)production rate,H utilization efficiency,CH_(3)OH conversion,CO concentration,and system heat balance are discussed thoroughly.The results indicate that the system can be operated in autothermal conditions with high-purity hydrogen(99.50 vol%)and ultra-low-concentration CO(<50 ppm)generation,which confirms the possibility of integrating low-temperature proton-exchange membrane fuel cells(LT-PEFMCs)with the SECL-OSRM process.The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H_(2)O/CH_(3)OH and MgO/CH_(3)OH mole ratios.
基金supported by the National Basic Research Program of China(973 Program,2011CB201202)of Ministry of Science and Technology of China(MOST)
文摘Two Cu-Mo-Fe-Ox samples, which can store and supply pure hydrogen through repeated redox reaction （Fe3O4＋4H23Fe＋4H2O）, were prepared by co-precipitation （FCM-C） and impregnation （FCM-I） methods, respectively, and the performance of hydrogen production from water were investigated. Compared with the impregnated sample, the co-precipitation sample presented better catalytic activity. The samples were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM）, X-ray photoelectron spectroscopy （XPS）, Fourier transform infrared spectroscopy （FT-IR） and temperature-programmed reduction （H2-TPR） techniques. XRD, FE-SEM and XPS results suggest that the FCM-C sample has smaller particle size and higher dispersion of iron oxide than that of FCM-I sample. In addition, FT-IR and H2-TPR analyses indicate that the weak interaction among metal oxides in FCM-C sample may induce facile reduction of active metal and superior property of hydrogen production by decomposing water in success
基金supported by National Natural Science Foundation of China (U20B6002, 51761145012, and 21525626)the Program of Introducing Talents of Discipline to Universities (BP0618007) for financial support
文摘The chemical looping steam reforming(CLSR)of bioethanol is an energy-efficient and carbon-neutral approach of hydrogen production.This paper describes the use of a Ni_(x)Mg_(1-x)O solid solution as the oxy-gen carrier(OC)in the CLSR of bioethanol.Due to the regulation effect of Mg^(2+)in Ni_(x)Mg_(1-x)O,a three-stage reaction mechanism of the CLSR process is proposed.The surface oxygen of Ni_(x)Mg_(1-x)O initially causes complete oxidation of the ethanol.Subsequently,H_(2)O and bulk oxygen confined by Mg^(2+)react with etha-nol to form CH_(3)COO^(*)followed by H_(2) over partially reduced Ni_(x)Mg_(1-x)O.Once the bulk oxygen is con-sumed,the ethanol steam reforming process is promoted by the metallic nickel in the stage Ⅲ.As a result,Ni_(0.4)Mg_(0.6)O exhibits a high H_(2) selectivity(4.72 mol H_(2) per mole ethanol)with a low steam-to-carbon molar ratio of 1,and remains stable over 30 CLSR cycles.The design of this solid-solution OC pro-vides a versatile strategy for manipulating the chemical looping process.
基金the National Key Research and Development Plan(No.2017YFE0112500)State Key Laboratory of Clean Energy Utilization(Open Fund Project No.ZJUCUE2022018)National Natural Science Foundation of China(No.51806192)。
文摘Hydrogen is an attractive energy carrier due to the high conversion efficiency and low pollutant emission.Chemical looping hydrogen production(CLHP)is an available way for producing high purity hydrogen with relatively low penalty energy and CO_(2)is captured simultaneously.Three reactors are usually contained for CLHP system including air reactor(AR),fuel reactor(FR)and steam reactor(SR).In current work,we focus on the performance of CLHP system,which is the basement for operation and design.Numerical simulations are carried out for analyzing the flow behavior and the numerical structure is built according to the experimental unit constructed at Southeast University,China.Results show that the operation of L-valve influences most the solid circulating rate of system and particles pass L-valve easily with large aeration rate.Mass distribution results indicate that fuel reactor has the capacity for particles storage.Increase of gas inlet rate of steam reactor leads to more particles leave steam reactor and accumulate into fuel reactor.L-valve can prevent the gas leakage between reactors and it will be adopted for reactive unit.Combining the operation of fuel reactor and L-valve,the system can reach steady state and get the regulating ability.
基金the specialized research fund for the Doctoral Program of Higher Education, Ministry of Education of China (Grant No. 20070003033)
文摘Hydrogen generation through thermal chemical water splitting technology has recently received in- creasingly international interest in the nuclear hydrogen production field. Besides the main known sulfur-iodine (S-I) cycle developed by the General Atomics Company and the UT3 cycle (iron, calcium, and bromine) developed at the University of Tokyo, the thermal cycle based on metal oxide two-step water splitting methods is also receiving research and development attention worldwide. In this work, copper ferrite was prepared by the co-precipitation method and oxygen-deficient copper ferrite was synthesized through first and second calcination steps for the application of hydrogen production by a two-step water splitting process. The crystal structure, properties, chemical composition and δ were investigated in detail by utilizing X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal analysis (DTA), atomic absorption spectrometer (AAS), ultraviolet spectrophotometry (UV), gas chro- matography (GC), and so on. The experimental two-step thermal chemical cycle reactor for hydrogen generation was designed and developed in this lab. The hydrogen generation process of water splitting through CuFe2O4-δ and the cycle performance of copper ferrite regeneration were firstly studied and discussed.
基金supported by National R&D Program through the National Research Foundation of Korea,grant number 2021M3H4A1A01079300the Korea Research Institute of Chemical Technology Core Research Program funded by the Korea Research Council for Industrial Science and Technology,grant number KS2222-10National Natural Science Foundation of China(22109169).
文摘Electrochemical water splitting has been demonstrated as a promising technology for the renewable generation of green hydrogen from water.Despite the extensive progress in materials science,one particular challenge for further development towards industrial application lies in the rational design and exploitation of efficient and cost-effective materials,especially oxygen evolution reaction(OER)electrocatalysts at the anode.In addition,attempts to replace the OER with other more oxidizable anode reactions are being evaluated as a groundbreaking strategy for generating hydrogen at lower potentials and reducing overall energy costs while producing valuable chemicals simultaneously.Compared with Fe/Co/Ni-based compounds,Cu-based materials have not received extensive research attention for electrode designs despite their high conductivity and abundant earth reserves.In this review,combining with the advantages of a three-dimensional network structure of metal foams,we summarize recent progress on Cu foam(CF)-derived materials as efficient electrocatalysts towards pure water electrolysis and hybrid water electrolysis.The advantages of CF and design strategies to enhance the electrocatalytic activity and operational durability are presented first.Catalyst design and fabrication strategies are then highlighted and the structure-activity relationship is also discussed.Finally,we propose challenges and perspectives on self-supported electrodes beyond CF-derived materials.
