Gasification of organic material/CaO pellets with high-pressure steam

Pellets made from subbituminous coal, lignite and wood mixed with CaO were steam gasified with high-pressure steam (4.2 MPa) at various temperatures. The product gas was composed mainly of H-2 with a few other gases (CH4, CO2). Pellet reaction rates decreased in the following order: wood > lignite > subbituminous coal; however, the amount of H-2 produced decreased in the order: subbituminous coal > lignite > wood. Pellet size and morphology did not change significantly during pyrolysis and gasification at 923 K, but they did change significantly during gasification at 973 K. Eutectically melted calcium compounds were expelled from the pellets. The compressive strengths of the subbituminous coal pellets increased after pyrolysis and gasification, and the increase in pellet strength was promoted by increased gasification temperature. H-2 production seemed unaffected by CaO reuse.