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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 °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 H2/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. Download the full text: PDF | HTML

An improved process is provided for the removal of sulfur oxides from gas or vapor media containing oxygen and water by contacting said media with a catalytically-active carbonaceous char. The improvement is provided by the use of a catalytically-active carbonaceous char prepared by low-temperature carbonization and oxidation of a bituminous coal or bituminous coal-like material followed by exposure to a nitrogen-containing compound during the initial high-temperature exposure of the low-temperature oxidized char. Following this initial high-temperature treatment the material can be further calcined or activated as desired.

Calcined dolomite is a good catalyst in terms of its activity for gasification of residue derived from biomass hydrolysis for hydrogen production, whereas its fragility can cause trouble during operation. A novel modification method aimed at improving the strength of the calcined dolomite has been presented using magnesium nitrate as the modifier, which was introduced into the dolomite via a co-precipitation process. The strength of the modified dolomite can be up to 250 times as high as the unmodified one and can cause much less bed pressure drop and catalyst loss, though the activity is slightly lowered after modification. Keywords: calcined dolomite modification; catalytic gasification; hydrogen production; biomass hydrolysis; bioenergy; magnesium nitr