CO2 absorption and desorption using phase-separation gel

Phase-separation absorbent has attracted much attention to reduce energy consumption for CO2 capture, storage and utilization. In this work, to improve handling of the absorbents, we have developed a new semi-solid absorbent, phase-separation gel, which became clouded gel by CO2 absorption and returned to transparent by CO2 desorption. We measured amounts of CO2 absorption at 50 degrees C and desorption at 90 degrees C with 10 vol% CO2 gas mixed with N-2 gas. A cyclic capacity defined by the CO2 desorption amount of a phase-separation gel with solvent of 2-(ethylamino)ethanol/diethylene glycol diethyl ether was larger than those of the other homogeneous gels with 2-(ethylamino)ethanol/diethylene glycol monoethyl ether or diethylene glycol. Furthermore, the initial desorption flux of the phase-separation gel was larger than that of the absorbent solvent, suggesting that the phase-separation absorbent fixed inside the gels improves the initial desorption flux because of the larger interfacial area between the CO2-rich and CO2-lean phases inside the gel.

Automated summary

A new semi-solid absorbent, phase-separation gel, was developed to improve CO2 capture and desorption processes. The cyclic capacity and initial desorption flux of the gel were found to be higher than those of other homogeneous gels, suggesting that the phase-separation absorbent fixed inside the gels improves the initial desorption flux due to the larger interfacial area between the CO2-rich and CO2-lean phases.