关键词: 生物质, 催化, 高铝矾土, 稻草, 热解气, 焦油

Abstract: The effects of modifiers of bauxite and its concentration and reaction temperature on the pyrolysis of rice straw were investigated in the fixed bed reactor. According to the results, the optimum modifiers and concentration and reaction temperature were selected for the rice straw gasification experiment, which was conducted in the bubbling fluidized bed reactor. The influences of modified bauxite on the gasification characteristics and the tar yield of rice straw were studied in a bubbling fluidized bed reactor. The results showed that the effects of bauxite modified by different modifiers on the gasification characteristics of rice straw were different, and the four kinds of modifiers catalytic ability were CaCl2<Fe(NO3)3<CuCl2≈Ni(NO3)2. The effective coating of bauxite multiplied with the concentration increasing of CuCl2 modifier, and the amount of pyrolysis gas rose correspondingly. The low heat value of rice straw pyrolysis gas increased from 2.93 MJ/Nm3 to 3.89 MJ/Nm3. Furthermore, the increase of reaction temperature improved the components of pyrolysis gas. Compared with 650℃, the gas production of CO, H2 and CH4 increased by 40.6%, 110.8% and 70.0% at 800℃, and the low heat value of rice straw pyrolysis gas increased from 1.74 MJ/Nm3 to 4.09 MJ/Nm3. The modified bauxite improved the gas components of rice straw and reduced tar component and tar production rate. The content of tar decreased from 27.01 g/m3 to 20.09 g/m3 and tar production rate decreased from 29.06 g/kg to 23.10 g/kg. Meanwhile, the low calorific value of rice straw gasification gas increased from 3.74 MJ/Nm3 to 4.28 MJ/Nm3, and the gasification efficiency increased by 22.3%.

Key words: biomass, catalysis, bauxite, rice straw, pyrolysis gas, tar