Platinum Nanoparticles to Study Metal Location in Shape-Selective Hydrocracking
type: CreativeWork
description: In the petrochemical industry, bifunctional hydrocracking is used to further refine long chain hydrocarbon product molecules into smaller, more valuable fragments (such as diesel and aviation fuel). The current study is focused on using hydrocracking to increase diesel yield, as the preferred automotive fuel in terms of efficiency and environmental impact. However, even though conventional hydrocracking can significantly increase diesel yield, it is not selective to improving diesel quality. In a recent study by Brosius et al., 2016, the use of a Pt/MFI bifunctional hydrocracking catalyst in the presence of H2O has shown, for the first time, selective hydrocracking to produce not only a high yield but also high cetane number diesel product. The current study is a continuation of the work by Brosius et al., 2016, with a focus on improving the catalyst design and, in particular, the metal function, as in this study the Pt metal was supported using wet impregnation which does not allow for control of metal size and location. The hydrocracking mechanism consists of a (de)hydrogenation function at the metal sites and cracking/isomerisation steps at the acid sites. The reason a high yield of high cetane diesel is produced from hydrocracking over Pt/MFI in the presence of H2O is twofold: firstly, hydrocracking inside the MFI micropores is selective to C-type β-scission which results in linear cracking products, and secondly, H2O competes at the acid sites which allows for the desorption of the linear primary cracking products. From previous literature it is evident that metal location affects both activity and selectivity during hydrocracking over various catalyst types due to diffusion limitations. Furthermore, with hydrocracking over MFI, metal location is also expected to influence the amount of reactant molecules which crack inside the micropores. Therefore, the aim of this study was to quantify the extent that metal located inside or outside the micropores of MFI infl…
abstract: In the petrochemical industry, bifunctional hydrocracking is used to further refine long chain hydrocarbon product molecules into smaller, more valuable fragments (such as diesel and aviation fuel). The current study is focused on using hydrocracking to increase diesel yield, as the preferred automotive fuel in terms of efficiency and environmental impact. However, even though conventional hydrocracking can significantly increase diesel yield, it is not selective to improving diesel quality. In a recent study by Brosius et al., 2016, the use of a Pt/MFI bifunctional hydrocracking catalyst in the presence of H2O has shown, for the first time, selective hydrocracking to produce not only a high yield but also high cetane number diesel product. The current study is a continuation of the work by Brosius et al., 2016, with a focus on improving the catalyst design and, in particular, the metal function, as in this study the Pt metal was supported using wet impregnation which does not allow for control of metal size and location. The hydrocracking mechanism consists of a (de)hydrogenation function at the metal sites and cracking/isomerisation steps at the acid sites. The reason a high yield of high cetane diesel is produced from hydrocracking over Pt/MFI in the presence of H2O is twofold: firstly, hydrocracking inside the MFI micropores is selective to C-type β-scission which results in linear cracking products, and secondly, H2O competes at the acid sites which allows for the desorption of the linear primary cracking products. From previous literature it is evident that metal location affects both activity and selectivity during hydrocracking over various catalyst types due to diffusion limitations. Furthermore, with hydrocracking over MFI, metal location is also expected to influence the amount of reactant molecules which crack inside the micropores. Therefore, the aim of this study was to quantify the extent that metal located inside or outside the micropores of MFI infl…
author: Nel, Dayle
keywords: Chemical Engineering
date published: 2018
date modified: 2026-07-22T22:23:47Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Centre for Catalysis Research

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/36900