A detailed thermodynamic analysis of CO2 hydrogenation to produce methane at low pressure

Abstract

Evaluation of CO2, which is harmful to the environment, as an alternative energy source in CH4 production was investigated from a thermodynamic point of view. The methanation of CO2 is exothermic, however it does not occur at low temperatures due to the kinetic barrier. Thermodynamic modeling studies were carried out to determine the appropriate parameters in the reaction using the Gaseq software according to the Gibbs free energy minimization approach. For this purpose, the effects of H2/CO2 molar feed ratio (2, 3, 4 and 5), temperature (100–1100 °C) and pressure (1, 3, 5 and 10 atm) on CO2 conversion (XCO2) and CH4 selectivity (SCH4) were investigated. As a result, 99.87% XCO2 and 99.99% SCH4 were reached using the molar ratio of H2/CO2 = 4 at 1 at m and 100 °C. The CO2 methanation modeling study at low pressure range was studied in detail and low operating pressure proved to be appropriate.