Evaluation of Near-Isothermal\nPhase-Change CO<sub>2</sub> Capture Technology with Heat Pump

Developing low-energy decarbonization\ntechnology is crucial\nfor\nachieving large-scale CO<sub>2</sub> capture from industrial flue\ngas. During the absorption of CO<sub>2</sub>, phase-change solvents\n(PCSs) can be separated into a CO<sub>2</sub>-rich phase and a CO<sub>2</sub>-lean phase. By exclusively supplying the CO<sub>2</sub>-rich\nphase to the desorber for solvent regeneration, the need for sensible\nheat is eliminated as a result of the reduction of the amount of solvent.\nHowever, the heat absorbed by the CO<sub>2</sub>-lean phase remains\nunrecovered. This study proposes a near-isothermal CO<sub>2</sub> capture\ntechnology utilizing phase-change solvents (NI-PCSs-TCC) to recover\nthe reaction heat absorbed by the CO<sub>2</sub>-lean phase to compensate\nfor regeneration heat through a heat pump system. A Solvent-Technology\nMatching Method (STMM) is proposed, which helps to co-optimize the\nsolvent concentration and process operation parameters. The optimal\noperating range for the MEA/sulfolane/water solvent concentration\nand process parameters within the NI-PCSs-TCC is evaluated. NI-PCSs-TCC\ncan achieve an energy consumption of 2.16 GJ/t CO<sub>2</sub> between\nthe temperature ranges of 338.15–341.15 K for absorption and\n379.15–383.15 K for desorption. This energy reduction is possible\nwhile maintaining a capture efficiency of over 90% and a lean loading\nof 0.2540 mol of CO<sub>2</sub>/mol of amine.