Preliminary analysis of process flow sheet modifications for energy efficient CO2 capture from flue gases using chemical absorption

The energy penalty associated with solvent based capture of CO2 from power station flue gases can be reduced by incorporating process flow sheet modifications into the standard process. A review of modifications suggested in the open and patent literature identified several options, primarily intended for use in the gas processing industry. It was not immediately clear whether these options would have the same benefits when applied to CO2 capture from near atmospheric pressure combustion flue gases. Process flow sheet modifications, including split flow, rich split, vapour recompression, and inter-stage cooling, were therefore modelled using a commercial rate-based simulation package. The models were completed for a Queensland (Australia) based pilot plant running on 30% MEA as the solvent. The preliminary modelling results showed considerable benefits in reducing the energy penalty of capturing CO2 from combustion flue gases. Further work will focus on optimising and validating the most relevant process flow sheet modifications in a pilot plant.