Influences of metal-modification and lamellar zeolite structure on ethylene to liquid aromatics conversion reaction using MFI catalysts

FUEL

卷:256

Article

Mahoney, Luther¹  Emdadi, Laleh¹  Leff, Asher C.¹  Tran, Dat T.¹  Wu, Wei²  Cheng, Sichao²  Liu, Dongxia²  Nguyen, Chi K.³  Lee, Ivan C.¹ 

[1] CCDC Army Res Lab, FCDD RLS, Sensor & Electron Devices Directorate, 2800 Powder Mill Rd, Adelphi, MD 20783 USA

[2] Univ Maryland, Dept Chem & Biomol Engn, College Pk, MD 20742 USA

[3] US Mil Acad, Dept Chem & Life Sci, 646 Swift Rd, West Point, NY 10996 USA

关键词: Lamellar zeolite;    Metal doping;    Ethylene conversion to aromatics;    MFI zeolite;    Hierarchical zeolites;   

DOI  :  10.1016/j.fuel.2019.115953

来源: Elsevier

【 摘 要 】

The effects of meso-/microporous structure and metal-modification with gallium or zinc on catalytic performances of lamellar MFI zeolites in ethylene conversion reaction to liquid aromatics were investigated. TEM, XRD, Ar adsorption-desorption, UV-Visible spectroscopy, and H-2-TPR measurements showed that the zeolite structure is a pivotal factor for controlling the type of metal dopant species forming on zeolite, their size, and their distribution. Adding metal dopants to zeolite structure decreased the Bronsted to Lewis (B/L) acid site ratio in the zeolites and improved their catalytic performance. As a result, metal-modified lamellar MFI zeolites showed higher liquid aromatics yield and selectivity for mono-benzene alkylated aromatics and lower coke formation rate compared to their microporous commercial MFI analogies. Zinc-loaded lamellar MFI had the most efficient catalytic performance among all studied catalysts. This phenomenon can be explained by higher accessibility of reactants to active sites and facilitated transport of products from lamellar structure of this zeolite and the low B/L acid site ratio of this catalyst provided by metal-modification, which is more suitable for ethylene aromatization. A bifunctional reaction mechanism has been proposed based on the analysis results of reaction product distributions that demonstrates the effect of both zeolite acid sites and metal sites in conversion of ethylene to liquid aromatics over MFI zeolite catalysts.

【 授权许可】

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