CO2 regeneration performance enhancement by nanoabsorbents for energy conversion application

Abstract

Due to the recent increase in the consumption of energy and the use of fossil fuels, global warming has become a serious issue. To address this problem, CO2 gas, which is the major element of the greenhouse gases, should be captured, regenerated and converted to useful fuels. The Integrated Gasification Combined Cycle (IGCC) and cement process generate large amount of CO2, which are controlled through pre-combustion capture. However, this method has a disadvantage because the system temperature should be decreased to -20 degrees C or lower. Therefore, the development of new absorbent is required to reduce the energy consumed for refrigeration. There is a study that improved the CO2 absorption performance by adding Al2O3 nanoparticles to methanol. However, studies on the regeneration of CO2 in nano fluid absorbents (nanoabsorbents) are insufficient. Therefore, in this study, the CO2 regeneration performance in Al2O3 nanoabsorbents is evaluated. It is found that the regeneration performance of CO2 is improved by 16% by using nanoabsorbents compared to methanol. Furthermore, the CO2 regeneration chatacteristics of nanoabsorbents are analyzed by considering the detachment time of CO2 bubbles from the surface, the cross-sectional area of CO2 bubble, and the number of regeneration sites through the CO2 regeneration and bubble visualization experiments. It is concluded that the mechanism of surface effect is the most plausible to explain the CO2 regeneration performance enhancement by nanoabsorbents. (C) 2016 Elsevier Ltd. All rights reserved.