高铝矾土改性对稻草热解与气化特性的影响

Effects of modified bauxite on the pyrolysis and gasification of rice straw

在固定床中研究了高铝矾土改性剂及其浓度和反应温度对稻草热解产气特性的影响,选取固定床中最佳实验条件,在流化床中研究了改性高铝矾土床料对稻草气化特性及焦油产率的影响。结果表明,不同物质改性的高铝矾土对稻草热解产气特性的影响不同,4种物质提高稻草热解产气能力的顺序为CaCl2<Fe(NO3)3<CuCl2≈Ni(NO3)2。增加CuCl2改性剂浓度,其在高铝矾土上的有效负载量成倍增加,稻草热解产气量也增加,热解气低位热值由2.93 MJ/Nm3提高至3.89 MJ/Nm^3;反应温度提高对改善稻草热解产气组分有促进作用,800℃下CO,H2和CH4产量分别比650℃下增加40.6%,110.8%和70.0%,热解气低位热值从1.74 MJ/Nm^3升至4.09 MJ/Nm3。改性高铝矾土提高了稻草气化产气量,减少了焦油含量,焦油含量从27.01g/m^3降至20.09 g/m^3,气化产气低位热值由3.74 MJ/Nm3升至4.28 MJ/Nm3,气化率由28.25%提升至34.51%。

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 strawwere 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 theconcentration 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%.