Multi-objective techno-economic optimization of flue-gas dehumidification using triethylene glycol absorption with enhanced heat recovery

초록

This study presents a multi-objective techno-economic optimization of the flue gas dehumidification process using triethylene glycol (TEG) absorption to address the varying flue-gas humidity requirements for subsequent carbon capture, storage, and conversion processes. Two key factors of dried flue gas humidity and total annualized cost were evaluated. To enhance the process efficiency, a waste heat recovery system was integrated, in which high-temperature water vapor from the TEG regenerator distillate was used to preheat the TEG/water mixture exiting the absorber, reducing operating costs by approximately 10%. Following multi-objective optimization, the process variables and key performance indicators corresponding to Pareto-front solutions at various dehumidification levels (50–15,000 ppm) were analyzed from a techno-economic perspective. Additionally, local and global sensitivity analyses supported by artificial neural network ensembles were performed to identify critical process variables. The results indicated that at low moisture-removal levels, TEG dehumidification was primarily governed by the TEG-to-moisture ratio, whereas at higher removal levels, energy consumption became the dominant factor. Additionally, a comparative analysis was performed under different flue-gas flow rates (5–500 t/h) and carbon tax scenarios. Overall, this study underscores the importance of heat integration and robust multi-objective optimization frameworks in TEG-based flue-gas dehumidification, enabling a detailed techno-economic evaluation across different moisture-removal levels. © 2026 Elsevier Ltd.

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