Process Intensification of CO2 Desorption

Anthropogenic climate change due to, among other causes, unhindered CO2 emissions is a major concern worldwide. The post combustion capture (PCC) process using a solvent, known as chemical absorption, is currently the most effective way to reduce CO2 emissions from large point sources. However, high capital investment costs when using the conventional packed bed absorber/desorber technology and high energy requirements during solvent regeneration are the primary obstacles for its large-scale implementation. Different process intensification (PI) technologies to desorb CO2 from the solvent have been introduced to mitigate the energy consumption compared to the conventional packed bed technology. This work reviews different technologies for intensification of CO2 desorption. In this context, rotating packed beds, microreactors, and membrane contactors have been explored as potential alternatives to intensify the desorption because of their superior mass and heat transfer. Alternative energy sources like ultrasound and microwaves have also been used to improve the desorption performance of conventional equipments. PI can also be realized by using novel solvents with improved desorption kinetics in combination with intensification equipment. Thus in this review, a comprehensive assessment of different existing PI technologies based on regeneration energies and regeneration efficiencies relative to conventional technology is presented. The intensification of mass transfer for the different technologies is compared, and a new parameter, named the regeneration factor, is proposed to evaluate the performance of PI equipment. This study outlines the advances in process intensification of CO2 desorption technologies to date and presents an overview of the merits and limits of all technologies.