IMPROVING METHYLCYCLOHEXANE DEHYDROGENATION WITH EX-SITU HYDROGEN SEPARATION IN A REACTOR-INTERSTAGED MEMBRANE SYSTEM

A system of two plug-flow reactors with an interstaged tubular palladi um-silver (Pd-Ag) membrane to ex-situ remove H-2 was used to improve t he efficiency of methylcyclohexane dehydrogenation. A monometallic nob le metal catalyst produced yields of toluene and hydrogen from methylc yclohexane which were much higher than those corresponding to equilibr ium at industrially relevant conditions. Experiments in this system at 593-673 K, 1-2 MPa, and overall liquid hourly space velocities of 1-2 .6 h(-1) afforded conversions up to 52% greater than those without mem brane and 35% greater than the equilibrium values for a conventional r eactor. However, the equilibrium conversions for the system itself wer e never exceeded. The membrane capacity was adequate to remove similar to 90% of the H-2 present in the first reactor product. Results obtai ned with the two reactors-membrane system were close to those predicte d using first reader conversion data.