Design and performance analysis of multi-tube membrane reactor for hydrogen production using CFD simulation

Abstract

A catalytic membrane reactor gives remarkable advantages compare to the conventional reactor on fuel conversion and operating conditions because it overcomes the thermodynamic equilibrium by continuously separating the hydrogen through Pd based membranes. For increasing the hydrogen productivity, a higher membrane surface area is required thus, a multi-tube membrane reactor can obtain more membrane area owing to its higher surface to volume ratio compare to a single-tube membrane reactor. Consequently, studying the multi-tube membrane reactor is required for its practical use in the industry. Two design parameters, number of tubes and tube pitch, is considered because increasing the tube diameter leads to decrease in surface to volume ratio besides tube length has limitation on its fabrication. Tube pitch affects mass and heat transfer inside the reactor and number of tubes is most relevant parameter to reactor scalability. In this study, investigations on design parameters of multi-tube membrane reactor have been carried out using computational fluid dynamics simulation. The reactor were designed based on tube pitch and number of tubes, and the performance of reactor was examined based on simulation. In addition, the hydrogen permeation with different locations as well as local distribution of reactor were discussed as the causes of performance change. As a result, it was confirmed that tube pitch is important parameter for optimizing the reactor design. Thus, the result revealed that the hydrogen permeation of each tubes was affected by the location of adjacent tubes.