(10b) Novel Microwave-Enhanced Non-Aqueous Slurry Process for Post-Combustion CO2 Capture

Sorbent regeneration plays a significant role in the adsorption/desorption cycles needed for effective CO₂ capture. This is because selective and efficient desorption can significantly increase the overall efficiency by allowing quicker sorbent bed turn-over and leading to a sorbent working capacity that approaches the maximum CO₂ capture capacity. Current state of the art methods involves a pressure/thermal swing, which often requires superheated steam for reactive regeneration. This leads to reduced efficiency due to longer regeneration times, incomplete CO₂ desorption and working capacities that are significantly lower than the sorbents maximum uptake capacity. Therefore, traditional absorptive carbon capture process leads to slower and inefficient capture/release stages that also increases cost.

In this work, Basic Immobilized Amine Sorbents (BIAS) were mixed with silicone oil as a novel slurry. These mixtures have been developed for post-combustion CO₂ capture to promote absorption/desorption process. This hydrophobic physical slurry has demonstrated rapid regeneration kinetics through the application of microwave (MW) technology. Results of infrared images showed that silicone oil barely absorbed the microwave energy, while BIAS sorbents, especially CO₂ saturated BIAS sorbents containing polar amine groups, strongly absorbed microwave energy. Experimental results showed that local MW heating can significantly expedite CO₂ release from the sorbent and reduce energy consumption during the regeneration process. FTIR spectra have proven that microwave heating didn’t damage BIAS sorbent, because silicone oil can disperse heat and therefore prevent sorbent from deactivation due to overheating. The regeneration processes under different microwave conditions have been systematically investigated.

This slurry process has also expressed improved hydrophobicity, and low or negligible corrosivity. Therefore, this novel MW-enhanced slurry method could provide a fast and highly energy efficient pathway for carbon capture.