A novel cascade fluidized-bed reactor assisted by hydrogen permselective membrane concept for improving gasoline productivity and selectivity in Fischer–Tropsch synthesis: A simulation study

•Simulation of cascade fluidized-bed reactor in Fischer–Tropsch synthesis.•Using hydrogen permselective membrane concept in second reactor.•Compensation of hydrogen lack in Fischer–Tropsch synthesis.•Simultaneous improving of the gasoline productivity and selectivity.

In this work, a novel cascade fluidized-bed reactor assisted via Pd/Ag membrane layer (CFBMR) for Fischer–Tropsch synthesis (FTS) is simulated, mathematically. In the first catalyst bed, the synthesis gas is partially converted to hydrocarbons in water-cooled reactor which is a fluidized bed. In the second bed which is a membrane assisted fluidized-bed reactor, the reaction heat is used to preheat the feed gas to the first bed. Due to the decrease of H2/CO to values far from the optimum reactant ratio, the membrane concept is suggested to control the hydrogen addition. This reactor configuration solves some observed weakness of conventional reactor (CR) such as high pressure drop, heat transfer problem and internal mass transfer limitations. Because of the inherent complexity of dense gas-particles flows, the two-phase theory in bubbling regime of fluidization is used to model and simulate the proposed reactor. The simulation results show an enhancement of gasoline yield, a main decrease in undesirable products formation and a favourable temperature profile along the proposed concept.