Evaluation of the Performance of Various Amine Based Solvents in an Optimized Multipurpose Technology Development Pilot Plant

AbstractThe overall goal of this work was to show experimentally using a CO2 capture plant of reasonable capacity the contributions of plant and solvent optimization to minimizing the steam requirement. Experimental studies were conducted in an optimized CO2 capture pilot plant to evaluate the performance of RS-1 solvent and 5 molar aqueous MEA. The first objective was to test a highly improved plant configuration that can minimize both the amine circulation rate and the steam requirements below the values reported in the literature for a desired CO2 recovery. The second objective was to show the superior performance of RS-1 relative to 5 molar MEA. Both these strategies were aimed at reducing the steam requirement without increasing the size or complexity of the CO2 capture plant. The pilot plant used for the tests was the highly optimized multi-purpose technology development plant at the International Test Center for CO2 capture which processes 186 Nm3/h of flue gas to produce CO2 with a nominal capacity of 1 tonne per day. This plant has 12-inch ID for the absorber and stripper columns. The inlet flue gas temperature was 40∘C while the CO2 concentrations in the flue gas were 4 and 8% based on exhaust gases obtained respectively from a natural gas turbine-natural gas boiler combination, and a natural gas boiler. The results show that for flue gas containing 4 and 8% CO2 for a 90% recovery or absorber efficiency, the steam duties using our optimized plant configuration were respectively 2.03 and 1.43 kg steam/kg CO2 for MEA as compared to industry and literature values based on conventional plant configuration in the range of 1.9 to 2.5 kg steam/kg CO2 depending on the CO2 concentration in the flue gas. When RS-1 solvent was used, the steam duties using the optimized plant configuration were respectively 1.74 and 1.35 kg steam/kg CO2 which showed improvements over the corresponding performance of 5 molar MEA. It was interesting to observe that with a completely modified and optimized process configuration, the heat duty using RS-1 was 1 kg steam/kg CO2. These results show that in order to minimize steam requirements in a post combustion CO2 capture amine plant, there is the need to optimize both the plant process configuration and the solvent