Analysis of the catalytic steam gasification mechanism of biomass

•The inner reaction of oxygen with carbon contained in the biomass is inevitable.•The gasification of biomass can result in the formation of residual carbon.•The methanation of CO2 is inevitable when almost all of CO is converted to CO2.•The theoretical maximum hydrogen and syngas yield cannot be actually achieved.•The series gasification technique of biomass and coal should be developed.

The gasification of cellulose was here used to prove that the inner reaction of oxygen with carbon contained in the biomass was unavoidable during the gasification of biomass. It was also proven that the dehydrogenation reaction and conversion of oxygen in biomass to CO always caused the formation of residual carbon. Although, almost all of oxygen contained in the biomass could be converted into CO by the catalytic effect of ions, which in turn could be converted to CO2, but the CO2 was always methanized. This indicated that the hydrogen and syngas yield contained in the product gas of biomass could not practically achieve to the theoretical maximum hydrogen and syngas yield from biomass. The present study showed biomass gasification connected in series with coal gasification to be an excellent approach to large-scale conversion of biomass to hydrogen and syngas.