A performance modelling study of integrating a MEA direct air capture unit with a CCGT absorber

Abstract

Even in optimistic decarbonisation scenarios, there are most likely to be residual emissions that cannot be captured at source or avoided. Hence, research on CDR technologies, such as DACCS, to identify ways for effective deployment is essential for achieving net-zero targets. The scope of CCS deployment will rely on the amount of the residual emissions and, at the current standard for point sources of 90% to 95% CO2 capture, DACCS can be strategically significant to global economies. Possible integration opportunities for a DAC absorber with a conventional amine CCGT+PCC plant are examined, termed Co-DACCS. Modelling results suggest that the combination of an air absorber with a typical flue gas absorber can achieve specific reboiler duties down to 3.5 GJ/tCO2 for separating CO2 from the air, a value in the range of standalone CCGT+PCC applications. Depending on the configuration, there appears to be some trade-offs between DAC absorber capital cost and energy consumption. Ways to optimise combined operation and to make PCC plants ‘DACCS-ready’ are also discussed.

Keywords: MEA direct air capture; hybrid DAC+PCC, negative emissions; process modelling