Energy & Fuels, Vol.22, No.2, 1233-1238, 2008
Preparation of hydrogen via catalytic gasification of residues from biomass hydrolysis with a novel high strength catalyst
Producing fuel alcohol via hydrolysis of lignocellulosic biomass leaves a considerable amount of residues waiting for treatment. A study was carried out on the preparation of hydrogen via catalytic gasification of residues from biomass hydrolysis with a novel Ni/modified dolomite binary catalyst, which was prepared by a two-step coprecipitation method and proved available for hydrogen production in terms of both activity and strength. The effects of four operation parameters, that is, the fluidized bed temperature, the catalytic fixed bed temperature, the particle size of the catalyst, and S/B (i.e., the mass ratio of steam to biomass material fed into the fluidized bed per unit time), on hydrogen yield were investigated. The results indicate that hydrogen yield increases with an increase in the temperature of either the fluidized bed or the downstream catalytic fixed bed or the S/B ratio or a reduction in the particle size of the catalyst. The optimum range for each of the four operation parameters from a comprehensive consideration is as follows: 800-850 degrees C for both the fluidized bed temperature and the catalytic fixed bed temperature, 1.5-2 for the S/B ratio, and 2.0-3.0 mm for the particle size of the catalyst. Furthermore, the gas product from catalytic gasification of residues from biomass hydrolysis contains less CO and CO2 and has a higher H-2/CO ratio compared with that of the sawdust. The hydrogen yield of the former is also much higher than that of the latter. These suggest that residues from biomass hydrolysis are an even better gasification material than the original sawdust. This paper provides A novel effective method for modifying the calcined dolomite, which endows the catalyst with satisfactory strength while retaining high activity, and opens a new promising way for utilizing the residues from biomass hydrolysis.