Experimental study on CO2 absorption in aqueous solutions and water-oil emulsions of TEA and blended MEA/DEA-TEA

The CO2 absorptions in aqueous solutions and water-in-oil (W/O) emulsions of TEA, MEA-TEA, and DEA-TEA were investigated. By applying an experimental setup, the effects of reactant concentration (0.25-1 M for TEA, 0.1-0.3 M for MEA/DEA), temperature (15-35 degrees C), volume fraction of the dispersed phase (0.4-0.6), and pressure (100-400 kPa) on capacity and rate of CO2 absorption were measured and compared. The CO2 absorption capacity in a TEA solution with a low/medium concentration (0.25-0.5 M) is more than the theoretical value while these values are approached to each other in the high concentration (1 M). The CO2 absorption capacity of blended solutions (MEA/DEA-TEA) is higher than that of the TEA solution. By increasing the temperature, the CO2 absorption capacities of the TEA and blended solutions are decreased by increasing the temperature. For the emulsion solutions, increasing the volume fraction of the dispersed phase causes a decrement in the capacity of absorption. In the low concentration of MEA/DEA (0.1 M), the aqueous solution has a higher absorption capacity than that of the emulsion while this trend is reverse in the high concentration of MEA/DEA (0.2-0.3 M). The CO2 absorption rates of emulsions are higher than the rates of their corresponding aqueous solutions. For the TEA solutions, the rate of CO2 absorption is controlled by the reaction rate while the shuttle mechanism enhances the absorption rate for the blended solutions. The CO2 absorption capacity and rate for the TEA and blended solutions are increased by pressure while this increment is more significant for the emulsions.