Chapter 7: Fischer–Tropsch Synthesis Reactors

Reactors are key components in large-scale commercial projects where reactions convert feed to product. Fischer–Tropsch synthesis converts small molecules (CO and H₂) into a wide range of hydrocarbons over a solid catalyst with some degree of tunable selectivity. The reaction products include petrol, diesel and wax. A reactor is not only a vessel that contains the catalyst, but it also determines the interactions between the catalyst, the reaction kinetics and the process streams. The primary goal when designing and operating a reactor is to create a suitable environment for the catalyst in order to sustain the desired reaction(s). Therefore, a good reactor design always considers the thermodynamics, kinetics, mass transfer and heat transfer related to the reaction, as well as the catalyst, the flow and mixing required in the reactor and the reactor type. Furthermore, the design must consider the possible risks during start-up, normal operation and catalyst regeneration, from both the engineering perspective, as well as with regard to the science behind the engineering. In this chapter, reactors that have been used in commercial FT projects are introduced, and their characteristics are discussed. The special requirements for reactors used in biomass-to-liquid plants are described, and current developments and potential future applications are introduced and discussed.