Biogas generally contains significant quantities of carbon dioxide in addition to methane. A bubbling column reactor operating at atmospheric pressure is proposed for cheap separation and a Mettler RC1 reaction calorimeter was used to build a simplified empirical model for measuring the molar heat of solubility of CO2 in aqueous solutions of monoethanolamine (MEA). Determinations were performed in 12 mass% MEA solutions regenerated at atmospheric pressure and reflux temperature for 3 h. Flows of CO2 from 174 to 917 mL min−1 were used at a reactor temperature of 283 to 353 K.