Dynamic modeling of pure hydrogen production via bio-ethanol steam reforming in a catalytic membrane reactor

Abstract

Ethanol steam reforming was performed in a catalytic membrane reactor (CMR) containing Pd-Ag membrane tubes selective to hydrogen and Pd-Rh/CeO2 catalyst. Experiments were performed at 923 K, 6-10 bar, and fuel flow rates of 50 to 200 µl/min using a mixture of ethanol and distilled water with steam to carbon ratio of 3. Moreover, dynamic experiments were carried out to observe the behavior of the CMR and obtain the time constant in case of desired pressure or fuel flow rate adjustment. A static model for the catalytic zone based on the experimental results was derived from the Arrhenius law as a function of fuel flow rate and operating pressure to simulate the production of H2 in the CMR. Based on the static model, pure hydrogen production rate was also simulated and a dynamic zonal model was proposed under ideal gas law assumptions to simulate the behavior of the CMR system regarding the production of pure hydrogen in isothermal conditions. This model resembled hydrogen flow rate adjustments needed to set the electric load of a fuel cell fed by the studied CMR system.