Reaction and hydrogen production phenomena of ethanol steam reforming in a catalytic membrane reactor

Ethanol steam reforming (ESR) can be performed efficiently using catalytic membrane reactors (CMR) to enhance H₂ production. To investigate the reaction of ESR and the effect of membrane on H₂ production, a numerical model was developed to predict the chemical reaction phenomena. The simulations suggested that lower Reynolds numbers were conducive to ethanol conversion and H₂ recovery. The H₂ yield could be increased by recovering H₂ from the ESR product gas using the Pd membrane, and the membrane had a better performance at low Reynolds numbers. Alternatively, total H₂ production increased at higher Reynolds numbers, but H₂ recovery decreased due to shorter residence time in the reactor. Increasing the S/E ratio enhanced the ESR performance to produce H₂ due to the excessive steam supplied to the reaction, but the H₂ recovery declined slightly and more energy would be required. Although a high inlet temperature increased the H₂ concentration on the retentate side, it also caused the membrane to experience a higher risk of melting. An increase in pressure facilitated both the ethanol conversion and H₂ recovery, scribing to more H₂ permeating through the membrane. Overall, the obtained results in this study are beneficial to ESR operation for H₂ production.