Coupling gas-assisted stripping and waste heat recovery for energy-efficient carbon capture process

A novel CO 2 regeneration process was designed by coupling gas-assisted stripping to waste heat recovery from the stripped gas, and this process was successfully implemented on a CO 2 regeneration test rig. N 2 was used as a model stripping gas to enhance CO 2 regeneration and introduced through one of two modes: into the bottom of the CO 2 stripper (the N 2 -bubbling mode) or at the side of the stripper (the N 2 -sweeping mode). Waste heat from the stripped gas, which was a mixture of H 2 O(g) and noncondensable gas, was also recovered and reintroduced into the stripper using the cold CO 2 -rich solvent bypassed from the main rich solvent stream. The experimental results verified that N 2 -assisted stripping could reduce the reboiler duty by enhancing the driving force for CO 2 regeneration. Compared to the traditional thermal regeneration process, the reboiler duty could be reduced by 7.9% in the N 2 -assisted stripping regeneration process. Furthermore, when waste heat of the stripped gas was recovered using a transport membrane condenser in the N 2 -bubbling regeneration mode, the maximum reboiler duty saving could reach 26.8%. Such gas-assisted stripping is applicable in the waste heat recovery system to reduce energy consumption through dual pathways, namely upgraded driving force for CO 2 regeneration and improved waste heat recovery. In future work, a more suitable stripping gas should be developed to facilitate CO 2 separation from the stripped gas. • A CO 2 regeneration test rig was built by incorporating gas-assisted stripping and waste heat recovery system. • Detailed results offer guidance for operation of gas-assisted stripping regeneration process. • Reboiler duty savings were verified in the gas-assisted stripping regeneration process by enhancing the CO 2 regeneration drive. • N 2 -assisted stripping was conducive to the improvement of waste heat recovery performance in TMC. • Reboiler duty saving up to 26.8% was achieved in TMC-based RS process coupled with N 2 -bubbling regeneration