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.

Sorption enhanced reaction for high purity products in reversible reactions

“…The only way to do that is using the stoichiometric ratio of H 2 O and CO in the feed. Jang et al studied the effect of H 2 O/CO ratio and noticed that the H 2 productivity increased dramatically around the H 2 O/CO ratio of 1.0, which was explained by the thermodynamics and stoichiometry of the WGS reaction. Here, we also studied the case where F CO = F H2O = 50 cm 3 /min (at 20°C and 101.3 kPa), F Ar = 0 and the bed is prefilled with argon.…”

“…Gomes and Yee studied propene metathesis with rhenium oxide catalyst and an improvement on product conversion was also noticed when adding 13X zeolite to the packing. A conversion rate for the dehydrogenation of cyclohexane into benzene exceeding the equilibrium limit was obtained by adding hydrogen adsorptive metal alloy in a reactor . Elsner et al studied the concept of SERP by the Claus reaction and the direct synthesis of hydrogen cyanide from carbon monoxide and ammonia.…”