Understanding coke formation and deactivation mechanism on zeolite based acid catalysts = 제올라이트 산촉매의 코크 생성 및 비활성화 메커니즘에 관한 연구

Cited 0 time in webofscience Cited 0 time in scopus
  • Hit : 24
  • Download : 0
Zeolite, a crystalline microporous aluminosilicate, is one of the most important solid acid catalysts applied in oil refinery, petrochemistry, and fine chemical synthesis due to its shape selectivity, strong acidity, and high thermochemical stabilities. Like other solid acid catalysts, zeolites suffer from deactivation resulting from coke formation during various hydrocarbon conversions. It serves as a major drawback in the application of the zeolite materials in high-demand catalytic processes. In this study, coke formation and deactivation mechanism of zeolite were rigorously investigated in the various acid-catalyzed reactions by analyzing the amount, composition, chemical nature, and location of coke generated on the zeolites having different crystallite sizes, secondary mesoporosity, and defect sites. Regardless of the types of the reaction or the reaction conditions, mass transfer of hydrocarbons within the zeolite crystals significantly affected the location of coke, whereas the amount of defect sites determined the total amount of coke deposited on the zeolite catalyst. By combining a variety of complementary analytic techniques, it is possible to propose that the internal coke (i.e. coke deposited within the zeolite micropore) is likely to have the polymeric structures of the methylated acenes connected via methylene bridges. On the other hand, the external coke (i.e. coke deposited on the external surface of the zeolite) is highly polyaromatic with many fused rings. In terms of catalyst deactivation, the internal coke proved to be more detrimental than the external coke. Overall, zeolite having a thin zeolite framework and minimized defect sites can hinder deposition of both internal and total coke amount, thus can serve as a long-lived solid acid catalyst. The present work would provide an important insights for understanding the deactivation behaviors of the zeolite catalysts and improving the eÿciency in various zeolite-based acid-catalyzed reactions.
Advisors
Choi, Minkeeresearcher최민기researcher
Description
한국과학기술원 :생명화학공학과,
Publisher
한국과학기술원
Issue Date
2020
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 생명화학공학과, 2020.8,[vi, 95 p. :]

Keywords

zeolite▼adeactivation▼acoke▼amesoporosity▼adefect site; 제올라이트▼a비활성화▼a코크▼a메조기공▼a구조결함

URI
http://hdl.handle.net/10203/284468
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=924557&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
Files in This Item
There are no files associated with this item.

qr_code

  • mendeley

    citeulike


rss_1.0 rss_2.0 atom_1.0