Several good reviews have been published in the last decades analysing the fundamentals and comparing different reactors for the FT synthesis (Dry, 1996; Dry, 2002; Geerlings et al., 1999; Guettel and Turek, 2009; Sie and Krishna, 1999). The heterogeneously catalyzed FT reaction is highly exothermic, with the heat released per reacted carbon atom averaging at about 146 kJ (Anderson, 1956), about an order of magnitude higher than heat released in processes typically applied in the oil industry (Sie and Krishna, 1999). Due to this extremely high
exothermicity, the rapid removal of heat is one of the major considerations in the design of FT reactors that have to be able to quickly extract the heat from the catalyst particles in order to avoid catalyst overheating and catalyst deactivation and at the same time maintain good temperature control. Moreover, the reaction usually takes place in a three-phase system, gas (CO, H2, steam and gaseous hydrocarbons), liquid hydrocarbons and solid catalysts, thus imposing great demands on the effectiveness of interfacial mass transfer in the reactor (Sie and Krishna, 1999). Last but not the least, the FT process is a capital-intensive process, and therefore, for both economic and logistic reasons, it is only economically favourable on a very large scale. Easy reactor scale-up is therefore a third important requirement when considering a reactor type for the FT process. Three main reactor types, discussed in the following paragraphs, have been commercialized or are thought as promising for industrial applications: multitubular fixed bed reactors, gas/solid fluidized bed reactors and three-phase slurry reactors.