Research On Hydrogen Production Process In Hydrothermal Reaction Of Biomass

With the development of human society and economy, the demands for the energy increased greatly; the traditional fossil fuels are going to be used up in this century, and the environmental problems caused by fossil fuels also get worse. The use of biomass, a regenerated energy, is very important to the sustainable development. And also, waste biomass materials consist of important parts of the solid waste. The change of waste biomass into energy or materials is significantly meaningful both to solve the energy problems and disposal the solid waste. A hydrothermal reaction process under sub-critical condition to transfer biomass to hydrogen and other useful materials is promoted in this research.Glucose was chosen as test material for carbohydrate biomass, which was studied to be transferred to formic acid under hydrothermal oxidation (HTO) condition. The hydrothermal oxidation of glucose produced great kinds of carboxylic acid and other organics. The reaction conditions were changed in a great range, to test the effect of different reaction conditions and also promote the best reaction conditions for formic acid production. In the normal hydrothermal oxidation, the best yield of formic acid, about 28% was achieved. The yield was little low according to the possible decomposition mechanisms of glucose, that hydrothermal alkali oxidation of glucose was performed to improve the yield of formic acid. Although under low alkali concentrations, formic acid yield was lower than that of normal HTO. Further increasing the alkali concentrations led to a significant increase in the formic acid yield. When KOH concentration increased to 1.25 M, a yield of formic acid about 75% was achieved. The mechanisms for hydrothermal oxidation of glucose were discussed: formic acid was supposed to be formed easily from the oxidation of glucose, but also decomposed easily and fast; the addition of alkali could prevent the decomposition of formic acid, which bring us a great yield of formic acid.Hydrogen production was detetected from the decomposition of formic acid in hydrothermal condition without oxygen supply. A great amount of hydrogen was...