Effect of phosphorus on novel bifunctional additives for enhancing the production of propylene and removal of SO2 in FCC process

Journal of Molecular Catalysis A: Chemical, Volume 340, Issues 1-2, 23 April 2011, Pages 99-107
Effect of phosphorus on novel bifunctional additives for enhancing the production of propylene and removal of SO2 in FCC process
Xiaoling Xu, Chunyi Li, Honghong Shan
muzixxl@163.com
chuli@upc.edu.cn
State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266555, Shandong, China
Abstract
The performance of magnesium-aluminate spinels as additives to a commercial equilibrium USY FCC catalyst for vacuum gas oil cracking and activity in oxidative adsorption of SO2 under similar FCC regenerator conditions were investigated.
The spinels were introduced into the matrix of typical propylene additives (ZSM-5 as the active component) to obtain a series of novel bifunctional additives for enhancing the production of propylene and removal of SO2. The substitution of MgAl2O4 for Kaolin clay in propylene additives causes the migration of Mg2+ into ZSM-5 zeolite, which evidently lowers the activity of ZSM-5 as an FCC additive, creating a bottleneck.. However, pretreating MgAl2O4 with phosphoric acid either by extraction or by impregnation method which weakened the interaction between MgAl2O4 and ZSM-5 during the steaming and calcination processes, respectively, proved to be effective in enhancing the efficiency of ZSM-5 for increasing propylene yield.
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