Effect of dilution in the experimental dehydrogenation of cyclohexane in hybrid membrane reactors

Abstract

The catalytic dehydrogenation of cyclohexane was studied in a hybrid membrane reactor to determine experimentally the optimum lengths of the packed bed and membrane reactor segments of the hybrid configuration. The conversions achieved in the pure membrane reactor were higher than those achieved in either hybrid membrane reactors or conventional packed bed reactors. Because of the large increase in the number of moles which accompanies the dehydrogenation reaction, dilution of the reactant has the effect of driving the reaction to higher conversions. Dilution is caused by the transport of inert sweep gas from the permeate side of the membrane reactor segment to the retentate stream in counterdiffusion to the product and reactant species leaving the retentate stream. The experimental results reflect the fact that for this application, the dilution effect is much more significant than the effect of product removal through the membrane.