Improving the energy efficiency of carbon capture process: The thermodynamic insight

The efficient use of energy is an important challenge in engineering tasks. Even with the end-of-pipe treatment method, the carbon capture process has possibilities to improve its efficiency with heat integration. Since exergy analysis helps detect the most efficient way of energy intensification, exergy investigation based on thermodynamic analysis is carried out to improve energy efficiency. Two cases for exergy destruction calculation can be considered and compared depending on the operation of the capture process: (i) the stand-alone situation, where utilities are applied, and (ii) the total site integration, where sources and sinks are available at every temperature level of the carbon capture process. Besides heat integration, the application of oxyfuel technology can further improve thermodynamic efficiencies reducing the detrimental exergy destruction. Air-combustion exhibits higher exergy destruction compared to oxyfuel-combustion, particularly at high carbon dioxide removal efficiency levels. Heat-integrated configurations nearly double thermodynamic efficiency, especially in the cases of oxyfuel technologies. Therefore, it is recommended that, for the sake of cleaner energy production, both oxyfuel technologies and heat integration should be applied to enhance carbon capture process' energy efficiency.