Syngas to isoparaffins: Rationalizing selectivity over zeolites assisted by a predictive isomerization model

• Published in: Fuel (Guildford) Vol. 285; p. 119233
• Main Authors: Xing, Chuang, Li, Mingquan, Zhang, Guihua, Noreen, Aqsa, Fu, Yajie, Yao, Miaohong, Lu, Chengxue, Gao, Xinhua, Yang, Ruiqin, Amoo, Cederick Cyril
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2021
• Subjects: Fischer Tropsch synthesis; Hydrocarbon fuel; Isoparaffins; Zeolites; Isoparaffins; Hydrocarbon fuel; Zeolites; Fischer Tropsch synthesis
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2020.119233

•Zeolite characteristics are exploited to rationalize isoparaffin production in FTS.•Co/SiO2 is paired with ZSM-5, Beta, and SAPO-11 zeolites for this investigation.•Synthesis of isoparaffins is ideal on zeolites with large pore sizes and mild acidity.•A tertiary isomerization bed is introduced that can improve branches on isoparaffins.
Direct synthesis of branched alkanes (isoparaffins) from syngas via Fischer-Tropsch synthesis (FTS) remains a challenge and hence has attracted much attention. Although progress has been made in exploiting some solid acids as catalyst to improve selectivity, a wide scope of uncertainty still exists in determining the major influential factors. Therefore, in this work, we investigate and presented the effects of zeolite characteristics such as the acidity, pore properties, and mass ratio on the selective production of isoparaffins in FTS. Co/SiO2 catalyst was coupled with the zeolites, Beta, ZSM-5, and SAPO-11 for this investigation. The results indicated that large pore acidic zeolites have the propensity to produce more multi-branched alkanes since they allow molecule proximity to facilitate isomerization. Also, strong acid sites tend to over-crack long-chain hydrocarbons to short-chains. The results of this study provide a rationale path capable of guiding the design of catalysts for optimized isoparaffin synthesis, directly from syngas.