**5. Conclusions**

Our study contributes to the overall knowledge of CO2 absorption under pressure. An absorber test rig was constructed and operated. Furthermore, a rate-based model was built by applying Aspen Plus software to simulate CO2 absorption using water as an absorbent. The model was validated against experimental data at di fferent operating points. The comparison between the results predicted by the rate-based model with the experimental data shows high agreement. The relative error was calculated between the gas concentration calculated using the model and those obtained from the results of the experiment to show the deviation of the model. An analytical study of the CO2 absorption process has also been presented, which highlights the following points:


This work is a contribution to the knowledge available for modeling studies for CO2 absorption using water as an absorbent in the sieve tray column. Our results confirm other quotes in the literature which are still limited to this issue.

**Author Contributions:** A.A. is responsible for preparing the original draft, developing the applied methodology, and supporting the writing process with his reviews and edits. F.A. conducted the conceptualization and supported the writing process with his reviews and edits. C.H. conducted the conceptualization and supported the writing process with his reviews and edits. B.E. supervised the research progress and the presented work. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors received no specific funding for this work. The corresponding author would like to thank the Technical University of Darmstadt, enabling the open-access publication of this paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
