Thermodynamic analysis of the CO2 methanation reaction with in situ water removal for biogas upgrading

• Published in: Journal of CO2 utilization 2018-07, Vol.26, p.271-280
• Main Authors: Catarina Faria, A., Miguel, C.V., Madeira, Luís M.
• Format: Article
• Language: English
• Subjects: Membrane reactor; Power-to-gas; Sorption-enhanced reactor; Substitute natural gas; Water removal
• ISSN: 2212-9820; 2212-9839
• DOI: 10.1016/j.jcou.2018.05.005

[Display omitted] •Biogas upgrading based on CO2 conversion by Sabatier reaction (CO2 methanation).•A thermodynamic analysis of the Sabatier reaction with in situ water removal.•A membrane reactor enhances the CH4 yield up to a certain water removal fraction (R).•Coke formation is favoured instead of methane above the optimum R.•The membrane reactor allows to comply with biogas grid specifications (for CO/CO2). This study assessed, from the thermodynamic point of view, the feasibility of methane production using CO2 present in raw biogas. The thermodynamic analysis of the Sabatier reaction was performed using the Aspen Plus software and considering in situ water removal to displace the reaction equilibrium. The temperature and pressure were varied between 200 – 450 °C and 1 – 30 atm respectively, the typical operation ranges of industrial catalysts. The CH4/CO2 molar ratio in the feed stream was also varied to evaluate the influence of biogas composition on methane yield and selectivity. Two types of multifunctional reactors could be considered depending on the value of the water removal fraction (R): a membrane reactor for 0