Catalytic cracking of C₅ raffinate to light olefins over lanthanum-containing phosphorous-modified porous ZSM-5: Effect of lanthanum content
2013
Lee, Joongwon | Hong, Ung Gi | Hwang, Sunhwan | Youn, Min Hye | Song, In-Kyu
Lanthanum-containing phosphorous-modified porous ZSM-5 catalysts (LaX-P/C-ZSM5) were prepared with a variation of La/Al atomic ratio (X=0.3, 0.7, 0.9, and 1.2) for use in the production of light olefins (ethylene and propylene) through catalytic cracking of C₅ raffinate. The effect of lanthanum content of LaX-P/C-ZSM5 catalysts on their physicochemical properties and catalytic activities for the cracking of C₅ raffinate was investigated. It was found that acidity of LaX-P/C-ZSM5 catalysts decreased with increasing lanthanum content, while basicity of LaX-P/C-ZSM5 catalysts increased with increasing lanthanum content. In the catalytic cracking of C₅ raffinate, acid and base properties of LaX-P/C-ZSM5 catalysts were closely related to the conversion of C₅ raffinate and selectivity for light olefins, respectively. Conversion of C₅ raffinate decreased with decreasing acidity of the catalyst and selectivity for light olefins increased with increasing basicity of the catalyst. Among the catalysts tested, La0.7-P/C-ZSM5 catalyst with moderate acidity and basicity exhibited the best catalytic performance in terms of yield for light olefins. It is concluded that an optimal lanthanum content of LaX-P/C-ZSM5 catalysts was required for maximum light olefin production in the catalytic cracking of C₅ raffinate.
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