Catalytic Performance of Bare Supporters and Supported KVO_3 Catalysts for Cracking n-Butane to Produce Light Olefins

Supported KVO3 catalysts were prepared by impregnating different kinds of supporters (α-Al2O3, γ-Al2O3 and SiO2 powders) with a KVO3 solution. The activity of the bare supporters and supported catalysts were evaluated in a continuous micro-reactivity test unit, with n-butane as a raw material. The results show that KVO3 has no catalytic activity, but it can increase the selectivity to light olefins. The supporter of α-Al2O3 has good catalytic performance for n-butane cracking when the reaction temperature is below 700℃.

溶析结晶法制备偏钒酸钾

采用溶析结晶法制备偏钒酸钾,确定高钒浓度下偏钒酸钾存在酸度范围。试验结果表明,钒浓度150 g/L,pH值7.6～8.5,溶析结晶法制备偏钒酸钾时溶析剂采用乙醇、加入量按体积比1∶1,搅拌60 min,结晶钒收率大于95%,偏钒酸钾纯度98%以上。在溶析结晶过程中结晶收率与溶析剂配比、结晶前钒浓度、结晶时间关系密切;结晶晶体中的铬随结晶前液钒浓度增加而增加,不随结晶时间的变化而变化,硅随结晶时间的增加而降低,不随结晶浓度的变化而变化,同时通过控制溶析剂加入量可控制结晶粒度。