In this study, computer simulation works have been performed for the capture process of the CO2 and H2S gases contained in the effluent stream using methanol aqueous solution. In order to increase the solubilities of the CO2 and H2S in the methanol aqueous stream, the operating pressure of the absorber was raised to 30 bar and the feeding temperature of the solvent was lowered to -20℃ by using refrigeration cycle. NRTL liquid activity coefficient model was used to estimate the liquid phase nonidealities for methanol and water. Soave-Redlich-Kwong equation of state was used for the vapor phase nonidealities. Henry's law option was also used to calculate the solubilities of the supercritical noncondensible gases into the methanol aqueous solvent stream.