Combined CO2 absorption/regeneration performance enhancement by using nanoabsorbents

Abstract

The reduction of in the emissions of CO2, which is the representative greenhouse gas, is actively investigated worldwide because of its contribution to global warming. Energy generation processes involving the gasification of fossil fuels separate the constituent gases before combustion occurs, rendering the capture of CO2 more attainable. Generally, CO2 is captured through an absorption method by using a liquid absorbent in large scale gasification systems. According to Henry's solubility law, the absorption and regeneration processes should be operated at low and high temperatures respectively, and these require high energy consumption. As a solution, nanoparticles are added to the absorbent (methanol) to reduce energy consumption required in the absorption and regeneration processes. In this study, the absorption/regeneration performance was evaluated through a lab-scale combined CO2-absorption/regeneration system. The nanoparticles used are SiO2 and Al2O3, which are added at a 0.01 vol% concentration. In the case of the Al2O3/methanol nanoabsorbent, the performance decreases as the number of cycle increases, whereas the performance is improved steadily in the case of the SiO2/methanol nanoabsorbent. Thus, the SiO2 nanoparticles are more suitable for the combined CO2 absorption/regeneration process. Furthermore, the mass transfer enhancement mechanisms of the absorption/regeneration process according to the addition of nanoparticles are presented. (C) 2016 Elsevier Ltd. All rights reserved.