CFD analysis and design of multi-tubular membrane reactor for dehydrogenation of cyclohexane

Abstract

Various R & D projects related to the use of hydrogen as a fuel are ongoing all over the world. Hydrogen storage and transport systems using chemical hydrides such as cyclohexane and methylcyclohexane, which have comparatively large contents of hydrogen exceeding 6 wt%, are of special interest. To recover high purity hydrogen from such chemical carriers, the palladium membrane reactor is expected to be more efficient than the conventional fixed bed type of equilibrium reactor. Therefore, scale-up development from the single membrane tube to the multitube type is important in terms of increasing the productivity for practical applications. A computational fluid dynamics (CFD) model for analyzing and designing a multi-tube type of palladium membrane reactor was developed, which considered the three dimensional mass and heat transfer for the dehydrogenation of cyclohexane occurring in the catalyst-packed bed. Simulation results were in good agreement with experimental data. In addition, the developed model could be used for further simulations such as improvement of the reactor performance by increasing the diameter of the membrane tube. The CFD model will be applicable to investigate the internal phenomena and quantitatively evaluating the reactor performance, and will be very useful for testing novel ideas, and scale-up and optimization of the membrane reactor design.