DEEP Dehumidification in cryogenic carbon capture systems: a Comprehensive REVIEW and critical assessment

• Limited reporting of dehumidification performance found in CCC literature; • Multi-stage dehumidification configurations are typically employed in CCC systems • CCC studies indicate convergence toward deep drying near 20 ppm moisture; • Solid desiccants appear most suitable for final flue gas residual moisture control; • Dehumidification must be treated as an engineered subsystem in CCC design. Cryogenic Carbon Capture (CCC) has emerged as a promising high-efficiency CO 2 separation technology capable of delivering high-purity streams. However, water vapor in flue gases constitutes a major operational constraint, as residual moisture may induce ice formation, equipment blockage, and process instability under cryogenic conditions. Consequently, deep dehumidification becomes a critical enabling step for reliable and energy-efficient CCC deployment. This work presents a systematic review of dehumidification strategies for CCC systems. From 304 screened publications, 46 addressed dehumidification in CCC, while only 16 reported quantitative data. This limited evidence highlights significant gaps in key parameters, including outlet humidity levels, operating conditions, and energy consumption, hindering comparison of alternative strategies and the definition of reliable operating targets. Additionally, reported CCC configurations rely mainly on cooling-based, compression-assisted cooling, and desiccant methods, typically implemented in multi-stage arrangements combining bulk moisture removal through cooling-condensation with a final polishing step to achieve ultra-low residual moisture. Available data indicate convergence toward similar outlet moisture levels, suggesting that deep dehumidification to about 20 ppm or lower, corresponding to a maximum dew point near −55°C, may represent a practical requirement for stable CCC operation. To compensate for scarce CCC-specific studies, conventional deep dehumidification technologies used in other industrial sectors were assessed. Solid desiccant systems appear particularly suitable for final-stage dehumidification, with desiccant-coated heat exchangers and fluidized beds exhibiting promising performance and favorable pressure-drop characteristics, respectively. These findings provide a structured basis for defining residual moisture targets and guiding integration of deep dehumidification methods in next-generation CCC systems.