过渡金属氧化物催化剂上水煤气还原冶炼烟气中SO_2

Investigation on reduction of SO_2 smelter off-gas with water-gas over transition metal oxide catalysts

采用浸渍法制备出系列过渡金属氧化物催化剂(Cu、Co、Fe和Ni),以模拟水煤气和模拟冶炼烟气为原料气,考察了活性组分、温度、空速、气配比和预硫化处理等对SO_2转化率和硫收率的影响。结果表明,Fe催化剂为最佳催化剂,SO_2转化率和硫收率均随温度的升高而增加,但温度过高,选择性变差,导致硫收率下降,最佳温度400℃;空速过大或过小均不利于反应进行,温度较高时,空速的影响较小,最佳空速3 000 h^(-1);气配比对反应的影响较大,SO_2烟气与水煤气体积比应控制在1.7左右。研究表明,金属硫化物是催化SO_2还原的活性相,反应机理应为中间产物机理。

A series of transition metal oxide catalysts （Cu, Co, Fe, Ni） were prepared by impregnation method. Effects of active components, temperature, GHSV, gas proportion and sulfiding on SO2 conversion and sulfur yield were investigated over the catalysts, using simulated water gas and smelter off-gas as the feed gas. The experimental results showed that iron oxide catalyst exhibited the best; SO2 conversion and sulfur yield increased with temperature, sulfur yield declined at excessively high temperature due to declining selectivity; excessively low or high GHSV would not favor the reaction, and influence of GHSV became minor at higher temperature; the optimal temperature and GHSV were 400℃ and 3 000 h^-1, respectively; smelter off-gas/water gas ratio had much influence on the reaction and should be kept at about 1.7. The results indicated that metal sulfides were the active components for catalytic reduction of sulfur dioxide and the reaction followed an intermediate mechanism.