Utilization of cyclohexanol dehydrogenation in a novel thermally coupled reactor for Fischer–Tropsch synthesis in gas to liquid technology

In this study, the dehydrogenation of cyclohexanol (CLL) and its utilization in a novel thermally coupled reactor for Fischer–Tropsch synthesis (FTS) has been investigated. In the new configuration, the produced heat of FTS reactions is removed by the endothermic reaction of CLL dehydrogenation instead of circulating high-pressure boiling water in the conventional reactor (CR). The products of this reaction are hydrogen and cyclohexanone (CLN). Some of the generated hydrogen is utilized in synthesis gas and also in hydro cracking unit for production of GTL products and other is stored and used in some other processes. Gasoline(C5+) – the desirable product – alongside some undesirable products like carbon dioxide and methane are produced in FTS reactions. To demonstrate the superiority and advantages of this new configuration it has been compared with another thermally coupled reactor for FTS in which the dehydrogenation of cyclohexane works as coolant reaction in the endothermic side of the reactor. In order to analyze this novel reactor a one-dimensional heterogeneous model has been applied. After modeling and solving the differential equations, the excellence and advantages of new configuration are clarified. The (C5+) yield is increased and a reduction in the generation of undesirable products like CO2 and CH4 is observed in this new configuration. Moreover, hydrogen and CLN which both are useful products are generated in considerable amounts in the endothermic side of the reactor.

► A novel configuration of thermally coupled reactor is proposed and simulated.
► Two endothermic reactions are used as coolant instead of circulating boiling water in the Fischer–Tropsch synthesis reactor.
► The comparison showed that CLL dehydrogenation was the best case due to more gasoline production.
► By applying the proposed configuration the volume of plant and both capital and operating costs would be reduced.