Modeling and simulation of non-isothermal packed-bed membrane reactor for decomposition of hydrogen iodide

HI decomposition using a membrane reactor is one of the important steps in hydrogen production by the thermal splitting of water using the Sulfur-Iodine cycle. Though, this reaction is endothermic. The mathematical model available to study the performance of such a reactor is an isothermal model. In this study, a non-isothermal mathematical model is developed by microscopic material and energy balance across the length of the membrane reactor. Experimental results from the literature are used for validation of the developed model. Comparing the simulations from the developed model and already reported isothermal model showed significant differences, which endorses the importance of the developed model. Later, the effects of different operating and design parameters were analyzed. Higher feed temperature (950-1000 K), lower feed pressure (100,000-150,000 Pa), lower feed flow rate (<200 ml/min), lower permeate pressure (<2500 Pa) and low to moderate N-2/HI ratio (0.3-0.4) were found to be the optimum operating conditions. Similarly, the conversion also increased with increasing reactor length, membrane area, and membrane permeance but eventually became constant. Reactor length around 0.4 m, membrane area around 0.008 m(2) and membrane permeance around 2 x 10(-7) mol m(2) Pa-1 s(-1) were estimated to be the optimum design conditions for the maximum HI decomposition. (C) 2020 Elsevier B.V. All rights reserved.