Department of Urban and Environmental Engineering (Environmental Science and Engineering )Currently, global warming is accelerating and greenhouse gases are known to be the main cause. Therefore, various studies on the reduction of greenhouse gases have been carried out in order to solve global warming around the world. The purpose of this study is to separate carbon dioxide and methane from biogas in anaerobic digesters to reduce carbon dioxide, which accounts for a large proportion of greenhouse gases. As a criterion for selecting a suitable solvent, not only the reduction of carbon dioxide but also the recycling of collected carbon dioxide was also observed. This study on the solvent which plays a dominant role in the physical interaction rather than the chemical interaction with the carbon dioxide enables us to improve the reuse efficiency of the solvent through the increase and decrease of the pressure. In order to find a suitable solvent for the purpose of the experiment, the solvent was divided into five categories. Water was used as a basic comparison of the experiments and pure solvents were used to increase the dissolved amount of carbon dioxide. We also used an aqueous solution of artificial seawater with salt added to the water to determine how salt influences the degassing of the anaerobic digestion gas (AD gas). The aqueous solution was used to confirm the synergy effect between water and solvent. Finally, the experiment was carried out by mixing acetone-based solutions with various advantages in pure solvent form. To maximize the merits of each solvent, we have combined three tertiary systems: water with the advantage of increasing the rate of carbon dioxide degassing, salt that can lead to a salting out effect, and acetone, which can increase the solubility of carbon dioxide. Compared with other experimental conditions in the tertiary system, it was possible to capture a high rate of carbon dioxide in the degassed AD gas with increasing solubility of carbon dioxide. It is concluded that the tertiary system is the best condition for the experimental purpose in the case of containing a small amount of water.clos
