An experimental study of hydrogen production by gasification of biomass in the presence of a CO2 sorbent

The paper presents a novel technique that enhances the hydrogen yield of conventional biomass steam gasification. This is done by integrating the gasification and absorption reactions. The method involves steam gasification of a carbonaceous fuel (biomass) in presence of a CO2 sorbent. Experiments were conducted by gasifying pine bark in presence of calcium oxide. The gasification was carried out at atmospheric pressure in the temperature range 500-700 degrees C. The hydrogen yield, total gas yield and carbon conversion efficiency increased by 48.6%, 62.2% and 83.5%, respectively, in the presence of sorbent at a gasification temperature of 600 degrees C. This was attributed to the reforming of tars and hydrocarbons in the raw product gas in presence of calcium oxide. The CO and CH4 concentrations in the product gas were lower while using the sorbent. The calcium oxide played the dual role of sorbent and catalyst. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.