Optimal design of CO selective methanation reactor based on field synergy principle for process intensification

Abstract

A novel jet-enhanced fixed tube array reactor is developed to improve CO selective methanation (CO-SMET) performance under varying operating conditions. Based on the field synergy principle for process intensification, a single jet-tube reactor configuration is first optimized via numerical simulations by adjusting the axial/circumferential jet-hole arrangements to improve flow and heat transfer characteristics. As a result, significantly higher convective heat transfer coefficient is obtained, while the maximum temperature rise is reduced by 85.0% compared to a conventional fixed-bed plug flow reactor. Next, a tube-array reactor with two-stage distributors and 19 jet tubes achieves enhanced gas distribution uniformity, exhibiting inlet velocity deviations below 0.83%. Optimal CO activity and selectivity occur at ∼2 vol.% CO and moderate velocities, while higher concentrations or temperatures favor CO₂ methanation. In the case of the inlet CO concentration of 0.1 vol.% and the reaction temperature of 473.15 K, the outlet CO concentrations range from 79 to 93 ppm, with CO selectivity up to 66.9% and negligible thermal rise (< 0.13 K), i.e. it effectively achieved desirable CO removal while suppressed hotspot due to CO₂ methanation. The proposed reactor design provides an effective approach for high-efficiency CO removal in hydrogen purification and synthetic fuel production.