Chapter 1 - Phase-Change Solvents for CO2 Capture

Abstract

Carbon dioxide (CO2) is a major greenhouse gas responsible for global warming; hence, much effort has been attracted to developing new materials and technologies for CO2 capture from process gas streams. Recently, phase-change solvents have emerged as one of the most promising approaches for CO2 capture. During the phase-change process, an absorbent will typically form two phases (e.g., two liquid phases or liquid–solid phases) after CO2 absorption. These two phases may be defined as CO2-rich and CO2-lean and can easily be separated from each other. The CO2-lean phase can be recycled back to the absorber and the CO2-rich phase can be sent to a stripper for regeneration. By regenerating only the CO2-rich phase, significant energy can be saved. In this chapter, we provide a comprehensive review of the state-of-the-art research activities related to phase-change solvents, including solvent design and characterization, and CO2 capture performance and process design. After a brief introduction of conventional chemical absorption, several new solvents are discussed. Next, the state-of-the-art research activities related to phase-change solvents for CO2 capture are highlighted. Our discussion concludes with some personal perspectives on future development in which phase-change solvents could be further studied.