A solid oxide electrolysis cell(SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational principle ...A solid oxide electrolysis cell(SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational principle of an SOEC for co-electrolyzing H2O and CO2to generate syngas was reviewed. The recent development of high temperature H2O/CO2co-electrolysis from solid oxide single electrolysis cell was introduced. Also investigated was H2O/CO2co-electrolysis research using hydrogen electrode-supported nickel(Ni)-yttria-stabilized zirconia(YSZ)/YSZ/Sr-doped LaMnO3(LSM)-YSZ cells in our group. With 50 % H2O,15.6 % H2and 34.4 % CO2inlet gas to Ni- YSZ electrode,polarization curves(I- U curves) and electrochemical impedance spectra(EIS) were measured at 800 ℃ and 900 ℃. Long-term durability of electrolysis was carried out with the same inlet gas at 900 ℃ and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.展开更多
The supercritical H2O/CO2 mixture is the working fluid to drive a turbine in a novel power generation system with coal gasified in supercritical water.This system is promising because of zero pollution emission in con...The supercritical H2O/CO2 mixture is the working fluid to drive a turbine in a novel power generation system with coal gasified in supercritical water.This system is promising because of zero pollution emission in contrast to the conventional coal-fired power plant.Heat transfer coefficients of the supercritical H2O/CO2 mixtures are important to design heat transfer devices in this system,which is similar to the role of heat transfer to supercritical water in conventional systems.However,heat transfer to supercritical mixtures has received less attention.Here,we show that the supercritical mixtures with H2O being one of the components,have similar convection heat transfer behavior to supercritical pure fluids for temperatures and pressures above the critical point of H2O.This phenomenon was demonstrated from two aspects.Firstly,the forced convection heat transfer coefficients of supercritical mixtures were numerically calculated using the simulation model for supercritical pure fluids and using the thermophysical properties(density,heat capacity,thermal conductivity and viscosity)of supercritical mixtures as input.The calculated results agree well with experimental data in the supercritical region.Secondly,the calculated results also agree well with the correlations for supercritical pure fluids.The mechanisms were investigated by molecular dynamics simulations on the diffusion of supercritical mixtures.These results lay the foundation for predicting convection heat transfer coefficients of supercritical mixtures and for designing heat transfer devices with supercritical mixtures as heat transfer fluids.展开更多
The chemical looping reforming of methane through the nonstoichiometric ceria redox cycle(CeO2/CeO2-δ) has been experimentally investigated in a directly irradiated solar reactor to convert both solar energy and meth...The chemical looping reforming of methane through the nonstoichiometric ceria redox cycle(CeO2/CeO2-δ) has been experimentally investigated in a directly irradiated solar reactor to convert both solar energy and methane to syngas in the temperature range 900–1050 °C. Experiments were carried out with different ceria shapes via two-step redox cycling composed of endothermic partial reduction of ceria with methane and complete exothermic re-oxidation of reduced ceria with H2 O/CO2 at the same operating temperature, thereby demonstrating the capability to operate the cycle isothermally. A parametric study considering different ceria macrostructure variants(ceria packed powder, ceria packed powder mixed with inert Al2 O3 particles, and ceria reticulated porous foam) and operating parameters(methane flow-rate, reduction temperature, or sintering temperature) was conducted in order to unravel their impact on the bed-averaged oxygen non-stoichiometry(δ), syngas yield, methane conversion, and solar reactor performance. The ceria cycling stability was also experimentally investigated to demonstrate repeatable syngas production by alternating the flow between CH4 and H2 O(or CO2). A decrease in sintering temperature of the ceria foam was beneficial for increasing syngas selectivity, methane conversion,and reactor performance. Increasing both CH4 concentration and reduction temperature enhanced δ with the maximum value up to 0.41 but concomitantly favored CH4 cracking reaction. The ceria reticulated porous foam showed better performance in terms of effective heat transfer, due to volumetric absorption of concentrated solar radiation and uniform heating with lower solar power consumption, thereby promoting the solar-to-fuel energy conversion efficiency that reached up to 5.60%. The energy upgrade factor achieved during cycle was up to 1.19. Stable patterns in the δ and syngas yield for consecutive cycles with the ceria foam validated material performance stability.展开更多
The Wulasigou Cu-Pb-Zn deposit,located 15 km northwest of Altay city in Xinjiang,is one of many Cu-Pb-Zn polymetallic deposits in the Devonian Kelan volcanic-sedimentary basin in southern Altaids.Two mineralizing peri...The Wulasigou Cu-Pb-Zn deposit,located 15 km northwest of Altay city in Xinjiang,is one of many Cu-Pb-Zn polymetallic deposits in the Devonian Kelan volcanic-sedimentary basin in southern Altaids.Two mineralizing periods can be distinguished：the marine volcanic sedimentary PbZn mineralization period,and the metamorphic hydrothermal Cu mineralization period,which is further divided into an early bedded foliated quartz vein stage（Q1） and a late sulfide-quartz vein stage（Q2） crosscutting the foliation.Four types of fluid inclusions were recognized in the Q1 and Q2 quartz from the east orebodies of the Wulasigou deposit：H2O-CO2 inclusions,carbonic fluid inclusions,aqueous fluid inclusions,and daughter mineral-bearing fluid inclusions.Microthermometric studies show that solid CO2 melting temperatures（T（m,CO2）） of H2O-CO2 inclusions in Ql are from-62.3℃ to-58.5C,clathrate melting temperatures（T（m,clath）l） are from 0.5 C to 7.5 C,partial homogenization temperatures（T（h,CO2）） vary from 3.3℃ to 25.9℃（to liquid）,and the total homogenization temperatures（T（h,tot）） vary from 285℃ to 378℃,with the salinities being 4.9%-15.1%NaCl eqv.and the CO2-phase densities being 0.50-0.86 g/cm-3.H2O-CO2 inclusions in Q2 have T（m,CO2） from-61.9℃ to-56.9℃,T（m,clath）from 1.3℃ to 9.5℃,T（h,CO2） from 3.4℃ to 28.7℃（to liquid）,and T（h,tot） from 242℃ to 388℃,with the salinities being 1.0%-15.5%NaCl eqv.and the CO2-phase densities being 0.48-0.89 g/cm-3.The minimum trapping pressures of fluid inclusions in Q1 and Q2 are estimated to be 260-360 MPa and180-370 MPa,respectively.The δ-（34）S values of pyrite from the volcanic sedimentary period vary from2.3‰ to 2.8‰（CDT）,and those from the sulfide-quartz veins fall in a narrow range of-1.9‰ to 2.6‰（CDT）.The δD values of fluid inclusions in Q2 range from-121.0‰ to-100.8‰（SMOW）,and theδ-（18）O（H2O） values calculated from δ-（18）O of quartz range from-0.2‰ to 8.3‰（SM展开更多
文摘A solid oxide electrolysis cell(SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational principle of an SOEC for co-electrolyzing H2O and CO2to generate syngas was reviewed. The recent development of high temperature H2O/CO2co-electrolysis from solid oxide single electrolysis cell was introduced. Also investigated was H2O/CO2co-electrolysis research using hydrogen electrode-supported nickel(Ni)-yttria-stabilized zirconia(YSZ)/YSZ/Sr-doped LaMnO3(LSM)-YSZ cells in our group. With 50 % H2O,15.6 % H2and 34.4 % CO2inlet gas to Ni- YSZ electrode,polarization curves(I- U curves) and electrochemical impedance spectra(EIS) were measured at 800 ℃ and 900 ℃. Long-term durability of electrolysis was carried out with the same inlet gas at 900 ℃ and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.
基金supported by the National Key R&D Program of China(Grant No.2016YFB0600100)the Fundamental Research Funds for the Central Universities(Grant No.30919011403)。
文摘The supercritical H2O/CO2 mixture is the working fluid to drive a turbine in a novel power generation system with coal gasified in supercritical water.This system is promising because of zero pollution emission in contrast to the conventional coal-fired power plant.Heat transfer coefficients of the supercritical H2O/CO2 mixtures are important to design heat transfer devices in this system,which is similar to the role of heat transfer to supercritical water in conventional systems.However,heat transfer to supercritical mixtures has received less attention.Here,we show that the supercritical mixtures with H2O being one of the components,have similar convection heat transfer behavior to supercritical pure fluids for temperatures and pressures above the critical point of H2O.This phenomenon was demonstrated from two aspects.Firstly,the forced convection heat transfer coefficients of supercritical mixtures were numerically calculated using the simulation model for supercritical pure fluids and using the thermophysical properties(density,heat capacity,thermal conductivity and viscosity)of supercritical mixtures as input.The calculated results agree well with experimental data in the supercritical region.Secondly,the calculated results also agree well with the correlations for supercritical pure fluids.The mechanisms were investigated by molecular dynamics simulations on the diffusion of supercritical mixtures.These results lay the foundation for predicting convection heat transfer coefficients of supercritical mixtures and for designing heat transfer devices with supercritical mixtures as heat transfer fluids.
基金The King Mongkut’s Institute of Technology Ladkrabang(KMITL),Thailandthe Franco-Thai scholarship program。
文摘The chemical looping reforming of methane through the nonstoichiometric ceria redox cycle(CeO2/CeO2-δ) has been experimentally investigated in a directly irradiated solar reactor to convert both solar energy and methane to syngas in the temperature range 900–1050 °C. Experiments were carried out with different ceria shapes via two-step redox cycling composed of endothermic partial reduction of ceria with methane and complete exothermic re-oxidation of reduced ceria with H2 O/CO2 at the same operating temperature, thereby demonstrating the capability to operate the cycle isothermally. A parametric study considering different ceria macrostructure variants(ceria packed powder, ceria packed powder mixed with inert Al2 O3 particles, and ceria reticulated porous foam) and operating parameters(methane flow-rate, reduction temperature, or sintering temperature) was conducted in order to unravel their impact on the bed-averaged oxygen non-stoichiometry(δ), syngas yield, methane conversion, and solar reactor performance. The ceria cycling stability was also experimentally investigated to demonstrate repeatable syngas production by alternating the flow between CH4 and H2 O(or CO2). A decrease in sintering temperature of the ceria foam was beneficial for increasing syngas selectivity, methane conversion,and reactor performance. Increasing both CH4 concentration and reduction temperature enhanced δ with the maximum value up to 0.41 but concomitantly favored CH4 cracking reaction. The ceria reticulated porous foam showed better performance in terms of effective heat transfer, due to volumetric absorption of concentrated solar radiation and uniform heating with lower solar power consumption, thereby promoting the solar-to-fuel energy conversion efficiency that reached up to 5.60%. The energy upgrade factor achieved during cycle was up to 1.19. Stable patterns in the δ and syngas yield for consecutive cycles with the ceria foam validated material performance stability.
基金funded by National Nature Science Foundation of China(41372096)
文摘The Wulasigou Cu-Pb-Zn deposit,located 15 km northwest of Altay city in Xinjiang,is one of many Cu-Pb-Zn polymetallic deposits in the Devonian Kelan volcanic-sedimentary basin in southern Altaids.Two mineralizing periods can be distinguished：the marine volcanic sedimentary PbZn mineralization period,and the metamorphic hydrothermal Cu mineralization period,which is further divided into an early bedded foliated quartz vein stage（Q1） and a late sulfide-quartz vein stage（Q2） crosscutting the foliation.Four types of fluid inclusions were recognized in the Q1 and Q2 quartz from the east orebodies of the Wulasigou deposit：H2O-CO2 inclusions,carbonic fluid inclusions,aqueous fluid inclusions,and daughter mineral-bearing fluid inclusions.Microthermometric studies show that solid CO2 melting temperatures（T（m,CO2）） of H2O-CO2 inclusions in Ql are from-62.3℃ to-58.5C,clathrate melting temperatures（T（m,clath）l） are from 0.5 C to 7.5 C,partial homogenization temperatures（T（h,CO2）） vary from 3.3℃ to 25.9℃（to liquid）,and the total homogenization temperatures（T（h,tot）） vary from 285℃ to 378℃,with the salinities being 4.9%-15.1%NaCl eqv.and the CO2-phase densities being 0.50-0.86 g/cm-3.H2O-CO2 inclusions in Q2 have T（m,CO2） from-61.9℃ to-56.9℃,T（m,clath）from 1.3℃ to 9.5℃,T（h,CO2） from 3.4℃ to 28.7℃（to liquid）,and T（h,tot） from 242℃ to 388℃,with the salinities being 1.0%-15.5%NaCl eqv.and the CO2-phase densities being 0.48-0.89 g/cm-3.The minimum trapping pressures of fluid inclusions in Q1 and Q2 are estimated to be 260-360 MPa and180-370 MPa,respectively.The δ-（34）S values of pyrite from the volcanic sedimentary period vary from2.3‰ to 2.8‰（CDT）,and those from the sulfide-quartz veins fall in a narrow range of-1.9‰ to 2.6‰（CDT）.The δD values of fluid inclusions in Q2 range from-121.0‰ to-100.8‰（SMOW）,and theδ-（18）O（H2O） values calculated from δ-（18）O of quartz range from-0.2‰ to 8.3‰（SM
