Thermochemical methane reforming using a reactive WO3/W redox system

The methane reforming process combined with metal oxide reduction was evaluated, for the purpose of converting solar high-temperature heat to chemicals below 1273 K. The metal oxide was endothermically reacted with methane, to produce CO, hydrogen and the component metal in the temperature range of 1173–1273 K. Of the metal oxide candidates, WO3 and V2O5 were found to be reactive and selective metal oxides for the purposes of methane reforming. The metallic tungsten produced by methane reforming could be used to split water and to generate hydrogen at a lower temperature of 1073 K. To improve the reactivities of WO3 for methane reforming and the subsequent splitting of water, supported tungsten oxides were examined in the temperature range of 1073–1273 K. The reactivities were much improved with the ZrO2-supported WO3, giving a methane conversion of 70% and a CO selectivity of 86%. Our findings indicate the possibility that the proposed two-step process using a WO3/W redox system may be a potentially new thermochemical path that produces useful energy carriers of processed metal, syngas and methanol for storing and transporting solar energy from the sun belt to remote population centers.

[1]  A. Steinfeld,et al.  The coal/Fe3O4 system for mixing of solar and fossil energies , 1997 .

[2]  T. Kodama,et al.  Efficient thermochemical cycle for CO2 gasification of coal using a redox system of reactive iron-based oxide , 1998 .

[3]  R. Palumbo.  Solar thermal chemical processing : Challenges and changes , 1999 .

[4]  A. Steinfeld,et al.  Coal Gasification Using the ZnO/Zn Redox System , 1996 .

[5]  Aldo Steinfeld,et al.  Optimum aperture size and operating temperature of a solar cavity-receiver , 1993 .

[6]  D. W. Gregg,et al.  Solar gasification of coal, activated carbon, coke and coal and biomass mixtures☆ , 1980 .

[7]  M Lundberg.  Model calculations on some feasible two-step water splitting processes , 1993 .

[8]  Aldo Steinfeld,et al.  Solar thermal production of zinc and syngas via combined ZnO-reduction and CH4-reforming processes , 1995 .

[9]  Y. Tamaura.  Starting scenario for global solar methanol delivery system, where solar energy is hybridized with coal by solar chemical process of coal gasification , 1998 .

[10]  K.-H. Funken,et al.  Catalytic thermochemical reactor/receiver for solar reforming of natural gas: Design and performance , 1998 .

[11]  R. Sizmann.  Solar Driven Chemistry , 1990 .

[12]  S. Yamauchi.  MALT: MAterials-oriented Little Thermodynamic Data Base for Personal Computers , 1985 .

[13]  Bernard M. Abraham,et al.  General Principles Underlying Chemical Cycles Which Thermally Decompose Water into the Elements , 1974 .

[14]  T. Kodama,et al.  Thermochemical conversion of coal and water to CO and H2 by a two-step redox cycle of ferrite , 1997 .

[15]  Anke Weidenkaff,et al.  A solar chemical reactor for co-production of zinc and synthesis gas , 1998 .

[16]  Antje Wörner,et al.  CO2 reforming of methane in a solar driven volumetric receiver–reactor , 1998 .

[17]  J. J. Ambriz,et al.  High temperature experiments with a solar furnace: The decomposition of Fe3O4, Mn3O4, CdO , 1982 .

[18]  Aldo Steinfeld,et al.  High-temperature solar thermochemistry: Production of iron and synthesis gas by Fe3O4-reduction with methane , 1993 .

[19]  T. Nakamura,et al.  Hydrogen production from water utilizing solar heat at high temperatures , 1977 .

[20]  E. Bilgen,et al.  An assessment of solar hydrogen production using the mark 13 hybrid process , 1985 .

[21]  Martin Flechsenhar,et al.  Solar Gasification of Biomass Using Oil Shale and Coal as Candidate Materials. , 1995 .