Improving the CO2 solubility in aqueous mixture of MDEA and different polyamine promoters: The effects of primary and secondary functional groups

Abstract

The main objective of this research is improving the CO2 solubility in aqueous solution of MDEA by different polyamines including ethylenediamine (EDA), diethylenethriamine (DETA), thriethylenetetramine (TETA), tetraethylenepentamine (TEPA) at low pressure conditions. Since the polyamines have more than one basic nitrogen groups, they could absorb CO2 with higher rate and capacity compared to tertiary amines such as MDEA. In this regard, the performance of prepared solutions are experimented in an isothermal batch reactor in the temperature range of 293.15–313.15 K, promoter fraction ranged from 0 to 15%, and pressure range 0–200 kPa. The prepared solvents are evaluated in terms of CO2 absorption capacity, initial absorption rate and regeneration efficiency based on the number of ratio of secondary to primary functional groups in the promoter. The results show that increasing the promoter fraction in the prepared solution improves the absorption capacity and rate. Based on the experimental data, the higher CO2 solubility, absorption rate, the boiling point and lower vapor pressure are the main advantages of the TEPA promoted MDEA solution in addition to higher absorption capacity and effective loading.