CO₂ post combustion capture with a phase change solvent. Pilot plant campaign

A new class of solvents, commonly referred to as phase change solvents, has a huge potential to significantly reduce the energy requirements of the CO₂ capture process. Aqueous solutions of DEEA and MAPA can form two liquid phases upon CO₂ loading depending on the amine concentrations. The 5M DEEA/2M MAPA mixture was tested in the Gløshaugen (NTNU/SINTEF) pilot plant. The phase change solvent showed to operate well in the pilot plant. Neither high viscosity nor foaming issues were noted. Absorption was reasonably fast and the CO₂ stripping in this system was easy due to the presence of the tertiary amine. Moreover, the system was able to operate at significantly lower specific reboiler duty and reboiler temperatures compared to the benchmark 30 wt.% MEA. The solvent was, however, more volatile than MEA and better control to avoid solvent losses is required. The experimental pilot campaign for the DEEA/MAPA system was validated toward a simulation model implemented in our in-house code CO2SIM. A total of 18 runs from the campaign were simulated with CO2SIM. A simplified thermodynamic model of the DEEA/MAPA system was successfully implemented in CO2SIM and can be used for further simulations of large scale plants.