ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The hydrothermal stability of the alkali-treated ZSM-5 and it’s catalytic performance in catalytic cracking of VGO

Dongmin Han, Yanhong Chen, and Chunyi Li

Shengli College China University of Petroleum, Dongying, China

E-mail: dongminzi@126.com

Abstract: To enhance the heavy oil cracking ability of ZSM-5, desilication by alkali has been adopted in this study. The results showed that desilication by NaOH, NaOH/Al(NO₃)₃, NaOH/(NH₄)₃PO₄ solutions all can induce some mesoporous structure to ZSM-5 zeolite. Among them, the sample ZSM-5/NaOH/(NH₄)₃PO₄-F showed the highest mesoporous surface area. The hydrothermal stability of the desilicated ZSM-5 samples was also measured. The NaOH-modified ZSM-5 sample exhibited worse hydrothermal stability than the parent ZSM-5, while NaOH/(NH₄)₃PO₄ modified ZSM-5 sample maintained the higher relative crystallinity and more acidic sites than the parent ZSM-5 after the hydrothermal treatment. The micro-activity tests showed that the NaOH/Al(NO₃)₃, NaOH/(NH₄)₃PO₄-modified ZSM-5 samples exhibited higher catalytic activity than the parent ZSM-5 sample and NaOH-modified ZSM-5 sample in catalytic cracking of vacuum gas oil (VGO). Especially, for the sample ZSM-5/NaOH/(NH₄)₃PO₄, the conversion of VGO increased from 78.91 to 85.13%, and the yield of propylene increased from 15.01 to 18.83% compared to the unmodified ZSM-5 catalyst.

Keywords: Alkali-treated ZSM-5 ; Mesopores ; Acidity ; Hydrothermal stability ; Phosphorus ; Catalytic cracking 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0572-x

Chemical Papers 73 (1) 215–220 (2019)