37. Fundamental study of H_2-rich clean gas production from woody biomass by steam gasification using a CO_2 sorbent : Investigation of the gasification mechanism

Abstract

Production of hydrogen-rich clean gas was conducted by steam gasification of woody biomass using calcium as a CO_2 sorbent at different reaction temperatures (200-650℃), in order to examine the gasification mechanism. From the results obtained, initially (<500℃) hydrogen mainly derived from shift reactions of steam with CO obtained by thermal degradation of the biomass structure and that by reforming of water-soluble tar. Then (>500℃) decomposition of heavy tar was promoted, resulting in a large increase in product gas yield. During the experiment, CO_2 evolved was completely absorbed into calcium as CaCO_3. Moreover, water-gas shift reaction successfully proceeded, since almost no CO was detected.