Investigating a HEX membrane reactor for CO2 methanation using a Ni/Al2O3 catalyst: A CFD study

In this contribution, viability of processing of the flue gas streams as a source of carbon dioxide for the thermo-catalytic conversion was investigated. For this purpose, a Ni/Al2O3 commercial catalyst with known chemical kinetics was utilized. Moreover, a transient mathematical model for dynamic catalyst deactivation was developed and validated with experimental results available in the open literature. The developed model was then uti-lized to understudy an air-cooled membrane reactor. Different tube configurations were understudied and compared to choose the conditions under which high conversion was feasible. Sensitivity analysis revealed that, the space velocity, cooling rate, and feed dis-tribution were all considered to be critical factors. It was revealed that, the presence of membrane resulted in higher conversion through the undertaken reactor. It made it possible to enhance reaction yield of non-membrane reactor through evenly distributing hydrogen along its length. A designed heat-exchanger (HEX) membrane reactor achieved 99% CO2 conversion when the coolant flow rate was reached to 10% of the coolant gravi-metric flow rate, feed space velocity was set at 100 h-1 and the feed pressure was set at 10 bars. & COPY; 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the feasibility of using flue gas streams as a source of carbon dioxide for thermo-catalytic conversion. A commercial Ni/Al2O3 catalyst with known chemical kinetics was used, and a mathematical model for catalyst deactivation was developed and validated. The model was utilized to study an air-cooled membrane reactor, and different tube configurations were compared to optimize conversion. Sensitivity analysis showed that space velocity, cooling rate, and feed distribution were critical factors. The presence of a membrane in the reactor improved conversion, allowing for even hydrogen distribution and achieving 99% CO2 conversion under specific conditions.