Experimental investigation of CO2 absorption capacity in amine blend of 2-amino-2-methyl-1-propanol (AMP) and tetraethylenepentamine (TEPA)

Abstract

In the light of increasing fears about climate change, greenhouse gas mitigation technologies have assumed growing importance. Carbon capture and sequestration (CCS) is one of the options that can enable the utilization of fossil fuels with lower CO2 emissions. There are different technologies for CO2 capture, but capture of CO2 by chemical absorption is the technology that is closest to commercialization. A number of different solvents in chemical absorption for CO2 capture have been proposed. The use of blended amines, a solution of two or more amines in varying compositions, shows considerable improvement in absorption and savings in energy requirements. This thesis focuses on developing a new solvent for an objective comparison of the performance with different solvents. In this work, the results of an experimental investigation on the solubility of CO2 in 2- amino-2-methyl-1-propanol (AMP), a primary sterically hindered amine and Tetraethylenepentamine (TEPA) having 5 amine sites (two primary and three secondary) as well as their mixtures are presented. It is observed, the ability of TEPA for CO2 uptake is higher as compared to that of AMP. The addition of TEPA to AMP enhances the CO2 loading capacity. Different mole ratio, CO2 partial pressure and total concentration of AMP-TEPA have been studied. TEPA has been observed as an excellent CO2 loading activator in aqueous AMP solution. CO2 loading is observed to increase up to 150 % with addition of TEPA upto 50 mole % in 1 M AMP solution at normal temperature and CO2 partial pressure of 10 kPa. 1 M AMP-TEPA removes 3 times more CO2 than 1 M MEA, however working with AMP-TEPA blend at higher concentrations proved challenging.