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Catalytic Cracking of Endothermic Fuels over Meso-HZSM-5/MCM-41 Coatings
journal contribution
posted on 2019-12-02, 23:13 authored by Zhenheng Diao, Di Rong, Xu Hou, Yinli Chen, Pengfei Zheng, Yingqian Liu, De SunNovel structured catalysts of meso-HZSM-5/MCM-41 composite
coatings
were synthesized via a two-step process: washcoating HZSM-5 powder
on the internal surface of a stainless steel tube and subsequently
converting SiO2 binder into MCM-41 by sequential desilication
and recrystallization. Additional Fe and Al species were incorporated
into the MCM-41 framework for increasing the active sites. It was
found that the adherence strength of composite coating was remarkably
improved, as a result of encapsulation of HZSM-5 crystals into the
successive MCM-41 network. Catalytic cracking of supercritical n-dodecane (500 °C and 4 MPa) was employed to test
the catalytic performance of the coatings. The ZC-Al/Fe coating with
both Fe and Al species incorporated into the MCM-41 framework showed
an excellent catalytic performance, with the initial conversion of n-dodecane enhancement by 50.6%, the deactivation rate reduction
by 64.5%, and the heat sink improvement by 14.5%, compared to the
parent HZSM-5 coating. The performance enhancement for ZC-Al/Fe coating
may result from the sequential precracking–cracking–dehydrogenation
reaction process catalyzed by acid sites in MCM-41, acid sites in
meso-HZSM-5, and redox sites in MCM-41, respectively.