A kind of solar thermochemical cycle based on methanothermal reduction of SnO2 is proposed for H2 and CO production. We find that the oxygen release capacity and thermodynamic driven force for methanothermal reduction...A kind of solar thermochemical cycle based on methanothermal reduction of SnO2 is proposed for H2 and CO production. We find that the oxygen release capacity and thermodynamic driven force for methanothermal reduction of SnO2 are large, and suggest CH4 :SnO2 = 2:1 as the feasible reduction condition for achieving high purities of syngas and avoiding vaporization of produced Sn. Subsequently, the amount of H2 and energetic upgrade factors under different oxidation conditions are compared, in which excess water vapor is found beneficial for hydrogen production and fuel energetic upgradation. Moreover, the effect of incom plete recovery of SnO2 on the subsequent cycle is underscored and explained. After accounting for factors such as isothermal operation and cycle stability, CH4 :SnO2 = 2:1 and H2O:Sn = 4:1 are suggested for highest solar-to-fuel efficiency of 46.1% at nonisothermal condition, where the reduction and oxidation temperature are 1400 and 600 K, respectively.展开更多
Inspired by the promising hydrogen production in the solar thermochemical(STC)cycle based on non-stoichiometric oxides and the operation temperature decreasing effect of methane reduction,a high-fuel-selectivity and C...Inspired by the promising hydrogen production in the solar thermochemical(STC)cycle based on non-stoichiometric oxides and the operation temperature decreasing effect of methane reduction,a high-fuel-selectivity and CH4-introduced solar thermochemical cycle based on MoO2/Mo is studied.By performing HSC simulations,the energy upgradation and energy conversion potential under isothermal and non-isothermal operating conditions are compared.In the reduction step,MoO2:CH4=2 and 1020 K<Tred<1600 K are found to be most favorable for syngas selectivity and methane conversion.Compared to the STC cycle without CH4,the introduction of methane yields a much higher hydrogen production,especially at the lower temperature range and atmospheric pressure.In the oxidation step,a moderately excessive water is beneficial for energy conversion whether in isothermal or non-isothermal operations,especially at H2O:Mo=4.In the whole STC cycle,the maximum non-isothermal and isothermal efficiency can reach 0.417 and 0.391 respectively.In addition,the predicted efficiency of the second cycle is also as high as 0.454 at Tred=1200 K and Toxi=400 K,indicating that MoO2 could be a new and potential candidate for obtaining solar fuel by methane reduction.展开更多
基金supported by the National Key R&D Program of China (Grant no. 2018YFB1502005)the National Natural Science Foundation of China (Grant nos. 51476163 , 51806209 and 81801768)Institute of Electrical Engineering, Chinese Academy of Sciences (No.Y770111CSC)
文摘A kind of solar thermochemical cycle based on methanothermal reduction of SnO2 is proposed for H2 and CO production. We find that the oxygen release capacity and thermodynamic driven force for methanothermal reduction of SnO2 are large, and suggest CH4 :SnO2 = 2:1 as the feasible reduction condition for achieving high purities of syngas and avoiding vaporization of produced Sn. Subsequently, the amount of H2 and energetic upgrade factors under different oxidation conditions are compared, in which excess water vapor is found beneficial for hydrogen production and fuel energetic upgradation. Moreover, the effect of incom plete recovery of SnO2 on the subsequent cycle is underscored and explained. After accounting for factors such as isothermal operation and cycle stability, CH4 :SnO2 = 2:1 and H2O:Sn = 4:1 are suggested for highest solar-to-fuel efficiency of 46.1% at nonisothermal condition, where the reduction and oxidation temperature are 1400 and 600 K, respectively.
基金supported by the Innovation Practice Training Program of College Students,Chinese Academy of Sciences(Application No.20184000028)the Practical Training Program of Beijing University of Higher Education High-level Talents Cross-cultivation(No.16053225)the National Natural Science Foundation of China(Grant Nos.51476163,51806209 and 81801768).
文摘Inspired by the promising hydrogen production in the solar thermochemical(STC)cycle based on non-stoichiometric oxides and the operation temperature decreasing effect of methane reduction,a high-fuel-selectivity and CH4-introduced solar thermochemical cycle based on MoO2/Mo is studied.By performing HSC simulations,the energy upgradation and energy conversion potential under isothermal and non-isothermal operating conditions are compared.In the reduction step,MoO2:CH4=2 and 1020 K<Tred<1600 K are found to be most favorable for syngas selectivity and methane conversion.Compared to the STC cycle without CH4,the introduction of methane yields a much higher hydrogen production,especially at the lower temperature range and atmospheric pressure.In the oxidation step,a moderately excessive water is beneficial for energy conversion whether in isothermal or non-isothermal operations,especially at H2O:Mo=4.In the whole STC cycle,the maximum non-isothermal and isothermal efficiency can reach 0.417 and 0.391 respectively.In addition,the predicted efficiency of the second cycle is also as high as 0.454 at Tred=1200 K and Toxi=400 K,indicating that MoO2 could be a new and potential candidate for obtaining solar fuel by methane reduction.
