A survey 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 flow sheet modifications to the standard process. Fifteen process flow sheet modifications for chemical based CO2 absorption processes are reviewed, with a particular focus on the patent literature. The proposed flow sheet modifications identify potentially moderate to large improvements in the energy performance of the chemical absorption process. Most process modifications suggested in the patent literature report very little if any supporting experimental evidence. Where supporting data does exist it tends to be based on process modelling results. Moreover, earlier patents tend to focus on the gas processing industry and it is not immediately clear whether the same benefits can be extended to CO2 capture from near atmospheric pressure flue gases. It is clear from the survey that there is considerable scope for achieving improved process performance through process flow sheet modifications. However further process modelling and, in particular, experimental work focused on post-combustion CO2 capture is needed to map the technical potential for improvements.