Fischer–Tropsch refining: technology selection to match molecules

Abstract

On a molecular level Fischer–Tropsch syncrude is significantly different from crude oil. When syncrude is treated as if it is a crude oil, its refining becomes inefficient. Refining technologies developed for crude oil can be employed to refine Fischer–Tropsch syncrude, but in order to conform to green chemistry principles (preventing waste; maximising atom economy; increasing energy efficiency) the technology selection must be compatible with the syncrude composition. The composition of Fischer–Tropsch syncrude is discussed in relation to the molecular requirements of transportation fuels and the refining gap that needs to be bridged. Conversion technologies are evaluated in terms of their refining objective, chemistry, catalysts, environmental issues, feed requirements, and compatibility to Fischer–Tropsch syncrude, in order to suggest appropriate technologies for efficient refining of Fischer–Tropsch products. The conversion technologies considered are: double bond isomerisation, dimerisation/oligomerisation, skeletal isomerisation, etherification, aliphatic alkylation, aromatic alkylation, metathesis, hydrogenation/hydrotreating, hydroisomerisation, hydrocracking, catalytic cracking, coking, thermal cracking, catalytic reforming, aromatisation, alcohol dehydration and olefin hydration.