Energy Generation from CO2 Capture Associated RED Power Generation System

Abstract

Today, global warming induced by green house gas (GHG) has been critical environmental issues. Among the direct GHGs, CO2 is the major gas which largely contributes to global warming. It is an issue of great concern to develop the cost effective carbon dioxide capture technology. However, current CO2 capture processes are becoming limited because these processes could not reached regeneration energy of 2.0 GJ/tCO2. Recently, it is reported that salinity gradient energy is one of most novel candidates for energy harvesting from CO2 (Hamelers et al., Environ. Sci. Technol., 1, 31, 2014). Reverse electrodialysis (RED) salinity gradient energy is the renewable energy which using concentration gradient between two different sources. And the energy potential of CO2 is larger than seawater in RED system. Therefore, we suggested the CO2 capture associated RED power generation system (CO2RED) to dramatically reduce the regeneration energy. This CO2 capture associated RED power generation technology is suggested for the first time. This proposed CO2RED system is possible to ensure the efficient power generation and economical CO2 capture performance using the concentration difference between the CO2 rich/lean solutions. We have make the lab-scale CO2 associated RED system. The RED stack comprised of five cell pairs. Each cell pair contained an anion and cation exchange membranes, spacers, and gaskets. In this study, we introduced the CO2 saturated absorbent to the RED system instead of seawater. As the results, CO2RED system achieved the power density of 0.8 W/m2. It was corresponded with 300 kJ/ton CO2 absorbent. Furthermore, pH of CO2 absorbent was changed from pH 7.9 to pH 8.4. It means that absorbed CO2 was transported through anion exchange membranes and the RED system can help to regenerate CO2 absorbent during the power generation. From this research, we have succeeded to obtain the core technology of CO2 associated RED power generation system and confirmed the possibility of this suggested CO2RED system for power generation technology.