The steam barrier as a design constraint in carbon capture: pathways to low-temperature regeneration

Point-source carbon capture is conventionally based on steam stripping to regenerate chemical solvents, creating a dependence on high-grade thermal energy and limiting integration with low-temperature heat sources. Steam-based regeneration is highly effective because it simultaneously supplies heat, promotes CO desorption, and facilitates production of a high-purity CO stream. Nevertheless, the widespread use of steam stripping should not be interpreted as evidence that high-temperature regeneration is the only viable pathway for CO release. In this Perspective, we examine solvent regeneration through the lens of energy quality and temperature-sensitive thermodynamic control variables, highlighting why CO desorption can occur at temperatures substantially below those required for conventional steam stripping. We connect observations across buffer systems, sterically hindered and tertiary amines, thermomorphic solvents, and enzymatically assisted capture to a common underlying mechanism: temperature-dependent acid–base equilibria and phase behavior that enable equilibrium-driven desorption without vaporization. Within this framework, carbonic anhydrase emerges not as a marginal absorber-side additive, but as a kinetic enabler that becomes viable under mild, low-temperature desorption conditions. Viewed through this lens, the steam barrier is revealed as one of multiple design options rather than a physical inevitability, opening systematic pathways toward carbon capture systems compatible with low-grade heat and improved exergy efficiency.