High temperature steam gasification of woody biomass – A combined experimental and mathematical modeling approach

• Much higher hydrogen production by high temperature pure steam gasification.
• Thermodynamic model developed to predict the syngas compositions and solid carbon deposition.
• The effects of solid carbon deposit are addressed.
• The optimal range of the steam to biomass molar ratio is recommended.
• The syngas heating value is high ranging between 9 and 10 MJ/m3.

The main objective of this study is to investigate the characteristics of woody biomass conversion to syngas using a steam allothermal gasification process. The entering steam maintained at 877 °C and 1000 °C, respectively was used as the gasifying agent. A lab scale apparatus was built to perform the gasification experiment and the produced syngas was accurately analyzed using gas chromatography. The results clearly indicate that the syngas from steam gasification contains relatively higher H2 concentrations, and the heating values of the syngas reach 9–10 MJ/m3. A thermodynamic equilibrium thermochemical model that accounts for the deposition of solid carbon as a function of the entering steam temperature and the steam to biomass molar ratio was developed. The model was successfully verified by experimental results. Based on the results of model, an optimal range of the steam to biomass molar ratio is recommended.