Process Intensification of Dehydrogenation Reactions by Pressure Swing Reactor

Abstract

Integration of catalytic reaction and separation operations is important for process intensification (PI). Experimental studies on promotion of the dehydrogenation reaction using hydrogen adsorbent during catalytic dehydrogenation reaction were reviewed. The promotion effect was lost after saturation of the adsorbent, so that regeneration under reduced pressure was essential to start the reaction again. The developed reactor was the so-called pressure swing reactor (PSR) or pressure swing adsorption type reactor (PSA reactor) after the cyclic operations of pressurization and evacuation. Dehydrogenation of cyclohexane, and dehydroaromatization of n-hexane, propane and methane were investigated. Pt/Al₂O₃–CaNi₅, Zn/H-ZSM-5–Mg₅₁Zn₂₀, Zn/H-ZSM-5–Ti fine powder, and Mo/H-ZSM-5–Ti fine powder catalysts showed high promotion effects. Because of the differences in reaction temperature, the recommended combination of catalyst and adsorbent varies depending on the reaction. Swing of partial pressure of hydrogen by inert purge gas regenerated the promotion effect showing the potential of the PSR for PI.