LIU Jia-xu1, LIANG Cui-cui1, XU Rui-fang1, LIU Guo-dong1, CHANG Xu-sheng1,2, GUO Hong-chen1
(1. State Key Laboratory of Fine Chemicals, Dept. of Catalytic Chemistry and Engineering，Dalian University of Technology, Dalian, Liaoning 116012
2. Shandong Qilong Chemical Co. Ltd, Zibo, Shandong 255400)
Abstract: By impregnating ions onto nano-sized HZSM-5 zeolite and carrying out the catalytic cracking of C4 liquefied petroleum gas (LPG) over the modified catalysts in a small fixed-bed reactor, the effect of different ions modification on the conversion of the butane and butene was investigated. Results show that,in the mixed C4 hydrocarbon feed,iso-butane is more active than normal-butane. However, the transformations ofbutene isomers are strongly related to their content in the feed. When the content of butenes in the feed is low, the total butene content tends to increase by formation. On the other hand, when the content of butenes in the feed is high, the total butene content tends to decrease by transformation. However, under any of these conditions, the content of butene isomers in products was seen generallyincrease at the sequence of butene-1, trans(cis)-butene-2, and iso-butene. The impregnation of the HZSM-5 zeolite with Zn2+ increases the conversion of iso-butane, but decrease the conversion of normal-butane. Zn2+ modified catalysts also show high aromatics selectivity at the cost ofgenerating more methane and ethane. The impregnation of the HZSM-5 zeolite with Fe3+ has little impact on the conversion of butane and butane, but has large effect on increasing the aromatics selectivity and decreasing the productivity of methane and ethane by-products. The combination of Zn2+ impregnation with Na+ reduces the conversion rate of iso-butane, normal-butane and 1-butene, and the selectivity of aromatics. However, it favors the productivity of ethylene and propylene obviously. The above-mentioned results provide beneficial information for the comprehensive utilization of C4 liquefied petroleum gas (LPG).
Key words: ion modification, HZSM-5 zeolite, C4 Liquefied Petroleum Gas, reactiveactivity, product distribution
E-mail: hongchenguo@163.com
Journal of Molecular Catalysis, Vol. 24, Issue 3, 2010, 208-216
