硫酸铵改性Al_2O_3负载Ni基催化剂的异丁烷脱氢性能

Catalytic performance of nickel catalysts supported on Al_2O_3 and sulfate modified Al_2O_3 in isobutane dehydrogenation

采用浸渍法制备了含NiO质量分数为20%的NiO/(SO2-4)w-Al2O3(w为SO2-4质量分数)催化剂,借助X射线衍射仪、热重分析仪等对催化剂的性能进行了表征,同时考察了催化剂在560℃时的异丁烷脱氢反应性能。结果表明,NiO/Al2O3催化异丁烷脱氢时,异丁烷几乎全部转化为CH4和积炭,目的产物异丁烯收率为零。以硫酸铵改性NiO/Al2O3作为催化剂,不仅能明显改善异丁烷脱氢产物分布,大幅度提高异丁烯的选择性,还能抑制积炭生成;NiO/(SO2-4)32-Al2O3催化异丁烷脱氢反应性能为最佳,在反应7 h时,异丁烷转化率和异丁烯收率可分别达到34.5%,23.8%。

NiO/（SO24- ） w - Al2O3 （w was the mass fraction of SO^-）catalysts with the mass fraction of 20% NiO were prepared by the incipient wetness im- pregnation method. The properties of catalysts were characterized by X - ray diffraction （ XRD ） and ther- mogravimetric analysis （TG）. Their dehydrogenation activities of isobutane were investigated at 560 ℃. The results showed that in the absence of sulfate modification,NiO/Al203 catalyzed the rapid rupture of C--C bond in isobutane which led to abundant for- mation of CH4 and coke. However, the treatment ofnickel catalysts with sulfate not only dramatically im- proved dehydrogenated product distribution and se- lectivity towards isobutylene but also decreased the rate of coke formation. With the optimal NiO/ （SO24- ）32 -Al2O3,the conversion of isobutane and yield of isobutylene achieved 34.5% and 23.8% re- spectively after 7 h.