Migration of potassium in an iron-based Fischer-Tropsch/zeolite composite catalyst

• Main Author: Gwagwa, Xoliswa Yolanda
• Format: Dissertation
• Language: English
• Published: University of Cape Town 2014
• Subjects: Chemical Engineering
• Online Access: http://hdl.handle.net/11427/5325

Includes abstract. === Includes bibliographical references (leaves 76-82). === The product of the Fischer-Tropsch synthesis is low in aromatics and as a result has relatively poor gasoline quality (with respect to the octane number). Due to the low octane value of gasoline, extensive work-up to improve the octane number is required. Thus the cracking of longer chain hydrocarbons and the oligomerisation of light olefins may increase the yield of gasoline products. The branched and aromatic products formed from skeleton isomerisation and aromatisation reaction over acid zeolites have a high octane number. Thus an alternative process proposed for the production of high quality gasoline from synthesis gas utilises a composite catalyst comprising of an alkali promoted iron based Fischer Tropsch (FT) catalyst and an acidic co-catalyst (ZSM-5) [Udaya et al, 1990; Schulz et al, 1991]. Therefore by using a zeolite combined with a Fischer Tropsch catalyst will result in an increase in the selectivity and quality of the gasoline range products [Botes and Böhringer, 2004, Schulz et al, 1991].