Intensifying heat transfer in Fischer-Tropsch synthesis on multi-tubular reactors loaded with washcoated and packed conductive foams

Temperature control is a crucial issue for the low-temperature Fischer-Tropsch synthesis which is a strong exothermic process. The adoption of multitubular reactors loaded with a highly conductive open-cell foam has been proposed as an alternative to conventional packed-bed reactors in order to approach the ideal plug-flow behavior while (i) enabling isothermal operation of highly endo and exo-thermic reactions, (ii) facilitating the intraparticle mass-transfer, and (iii) limiting pressure drop. In this work, we compare the performance of multitubular reactors loaded with washcoated open-cell conductive foams (washcoated-foam reactors) with the performance of multitubular reactors loaded with open-cell conductive foam packed with catalysts pellets (packed-foam reactors). The potential of reactors is investigated herein by means of a pseudo-continuous, heterogeneous, two-dimensional mathematical model of a single reactor tube. Simulations show that commercial foams washcoated with a Co/Al2O3 catalyst allow to operate the reactor according to a once-through scheme (70% CO conversion), keeping acceptable the temperature gradients on both the axial and the radial directions with very small pressure drops. Whereas, when packed-foam reactors adopt the same simulations, catalyst inventory and productivity can be relatively higher, and the gradient temperature is relatively lower than the washcoated-foam reactor. This result is achieved without the need of cofeeding to the reactor large amounts of liquid hydrocarbons to remove the reaction heat, as opposite to existing industrial Fischer–Tropsch packed-bed reactors. In addition, we also verify the packed-foam reactor simulation using data experiments. As a result, the output generated by simulation of packed-foam reactors are very close to the output of the experiments.