Chapter 4: Fischer–Tropsch Syncrude

Fischer–Tropsch syncrude is a complex multi-phase mixture and the syncrude composition depends on various factors related to the Fischer–Tropsch synthesis. The syncrude may contain synthesis catalyst and other undesirable compounds and pre-treatment of the syncrude is briefly discussed. After Fischer–Tropsch synthesis, different syncrude fractions are obtained from stepwise cooling of the primary products. The syncrude fractions that are typically obtained during industrial operation are described. Gaseous, liquid and solid (wax) hydrocarbons and the oxygenates present in the organic and aqueous phase products are reviewed with reference to the three main syncrude types, namely iron-based low temperature Fischer–Tropsch (Fe-LTFT), iron-based high temperature Fischer–Tropsch (Fe-HTFT) and cobalt-based low temperature Fischer–Tropsch (Co-LTFT) synthesis. Fischer–Tropsch syncrude, like conventional crude oil, has to be refined in order to obtain useful products. Major differences between syncrude and crude oil are highlighted, while pointing out how these differences affect the catalysis that is needed to upgrade each. From this discussion it is clear that Fischer–Tropsch refining catalysis is a different topic from crude oil refining catalysis, which serves as justification for this book. Fischer–Tropsch refining requirements are briefly discussed to serve as introduction to the chapters on catalysis.