Energy Efficient Solvents for CO2 Absorption from Flue Gas: Vapor Liquid Equilibrium and Pilot Plant Study

From solvent screening for new, amine based solvents for CO2 recovery from flue gas, two most promising solvent formulations, a 51 wt% New Solvent (NS) and a 26.7% AMP-11.9% HMDA mixture were selected and tested in an industrial pilot plant, mainly to identify the regeneration energy requirement. In the pilot plant tests CO2 absorption was done at 40 °C, 1.3 bar and regeneration at 120 °C, 2.0-2.2 bar, using both 5 and 10 vol% CO2 inlet concentration. At 90% CO2 recovery and optimized solvent circulation, the NS solvent was the most energy efficient, requiring only 2.48 and 2.26 MJ/kg CO2 for 5 and 10 vol% CO2 inlet concentration respectively, whereas the AMP-HMDA solvent required 3.62 and 3.41 MJ/kg CO2. Both solvents compare favorably to the 30wt% MEA reference measurements in the same pilot plant (4.80 resp. 4.33 MJ/kg CO2) showing the potential of these energy-efficient solvents