Advances and emerging techniques for energy recovery during absorptive CO2 capture: A review of process and non-process integration-based strategies

Absorptive CO2 Capture (ACC) is widely embraced as a mature technology to mitigate CO2 emission, but it is energy-intensive and expensive to implement on a commercial scale. It is envisaged that energy recovery could be achieved during ACC by synthesizing and integrating a complex network of flexible heat exchangers to transfer as much energy as possible from a set of hot flows to cold flows. This review provides information on the progress made in the development of process and non-process integration-based techniques alongside their benefits for effective energy recovery during ACC. An exposition on the integration of flexible Heat Exchanger Networks (HENs), its synthesis methodologies, and developments for improving energy recovery during ACC is presented. Furthermore, this review highlights the current state of knowledge creation in process integration and ACC, as well as its underpinning principles, challenges, and opportunities to provide a summary and important discussion on current practices in process integration-based strategies for energy recovery. Current opinions on the integration of flexible HENs for energy recovery during ACC are highlighted. The review also presents a proposed roadmap for large-scale energy recovery during ACC, and suggestions on the improvement opportunities for future research and development were provided. Finally, this review revealed that the integration of flexible HENs is a promising technique for energy recovery during ACC. This study will be beneficial to researchers exploring cost-effective methods for designing sustainable energy systems for effective energy recovery. •Emerging techniques for energy recovery during absorptive CO2 capture (ACC) are categorized.•A new perspective for energy recovery during ACC is proposed.•Non-process integration-based techniques are effective but increase process costs.•Integration of flexible heat exchanger networks is a reliable technique for energy recovery during ACC.•A proposed roadmap for large-scale energy recovery during ACC is presented.