Hydrogen production from woody biomass by steam gasification using a CO2 sorbent

In H2 production from woody biomass by steam gasification using CaO as a CO2 sorbent, the effect of reaction parameters such as the molar ratio of CaO to carbon in the woody biomass ([Ca]/[C]), reaction pressure, and reaction temperature was investigated on H2 yield and conversion to gas. In the absence of CaO, the product gas contained CO2. On the other hand, in the presence of CaO ([Ca]/[C]=1,2, and 4), no CO2 was detected in the product gas. At a [Ca]/[C] of 2, the maximum yield of H2 was obtained. The H2 yield and conversion to gas were largely dependent on the reaction pressure, and exhibited the maximum value at 0.6MPa. It is noteworthy that H2 was obtained from woody biomass at a much lower pressure compared to other carbonaceous materials such as coal (>12MPa) and heavy oil (>4.2MPa) in steam gasification using a CO2 sorbent. H2 yield increased with increasing reaction temperature. Woody biomass is the one of the most appropriate carbonaceous materials in H2 production by steam gasification using CaO as a CO2 sorbent, taking the reaction pressure into account.