Rational design of amine-based solid adsorbents for post-combustion CO2 capture

Abstract

As increasing concerns of the impact of greenhouse gases on global warming and climate change, the scientific community is making significant concerted efforts to develop efficient technologies for the reduction of CO$_2$ emissions. Post-combustion carbon capture and storage (CCS) based on retrofitting the existing energy infrastructure has attracted extensive attention as a practical short-term solution to control CO$_2$ levels. Among various post-combustion CO$_2$ capture technologies, amine-based solid adsorbents have been the most widely investigated due to their CO$_2$ chemisorption ability from humid flue gas containing low-concentration CO$_2$. By introducing high-loading amines into large-porosity supports, adsorbents with large CO$_2$ uptake/selectivity could be readily prepared. However, these materials are known to degrade via various chemical pathways including urea formation under CO$_2$-rich atmosphere at elevated temperatures, steam-induced degradation of porous supports, and oxidative degradation of amines. In the present thesis, I focused on not only the incremental CO$_2$ uptake/selectivity of the adsorbents but also other important engineering aspects such as efficient regeneration enabling purified separation of CO$_2$, various thermochemical stabilities (e.g., resistance against urea formation, steam degradations, oxidative degradations), and minimization of heat required for adsorbent regeneration. I successfully proposed various solutions for suppressing aforementioned degradation pathways. Also, I rigorously investigated energy efficiency of the adsorbents for rational design of amine-based adsorbent. Thus, this study provides important guidelines to design energy-efficient and stable CO$_2$ adsorbents in the viewpoint of commercial implementation.