Coupling a sterically hindered amine-based absorption and coal fly ash triggered amine regeneration: A high energy-saving process for CO2 absorption and sequestration

Abstract

Developing a promising process for CO2 sequestration with large capacities, fast kinetics and low energy requirements is still of great importance. Here, we developed a new CO2 sequestration process that integrates a sterically hindered amine based CO2 absorption and coal fly ash based amine regeneration. The present study investigated the technical feasibility of the new process and gained a detailed insight into the reaction mechanisms involved. We found that the CO2 rich 2-amino-2-methyl-1-propanol (AMP) solution can be chemically regenerated by CaO. The species analysis by FT-IR and 13C-NMR revealed that CaO was effective to regenerate AMP and combine with CO2 in the AMP solution to produce carbonate precipitates. The evaluation of the AMP regeneration using a CaO containing fly ash indicated that fly ash was also effective for AMP regeneration and CO2 mineralisation. The characterizations of the fly ash before and after mineralisation via SEM equipped with EDX and XRD confirmed that the CaO in fly ash played a decisive role in the process. The new approach developed in this work presents an alternative to the traditional thermal CO2 desorption process, which can save energy for amine regeneration significantly and has added benefit of direct CO2 mineralization.