Carbon dioxide separation from carbon dioxide-methane gas mixture using PSA utilizing inorganic and organic adsorbents

Carbon dioxide (CO₂) gas enrichment and separation process have been researched for decades and various methods are being applied in industries to reduce and resist CO₂ gas due to its corrosive characteristics and negative effects on environment. Greenhouse gases such as methane (CH₄) and CO₂ are the most abundant in natural gas wells. They contribute significant negative effects to global warming. In this research, Pressure swing adsorption method was utilized as a mechanism to capture and recover binary gas via gas separation process by adsorbents. The adsorbents used in this study were Zeolite SA, Zirconium-benzene dicarboxylate (UiO-66) and activated carbons made from Kenaf and palm kernel shell (PKS) within the pressure differences of up to 3 bars. The adsorbents were prepared and characterized using Brunauer-Emmett-Teller (BET) analysis and particle size distribution analysis. Adsorbents selection and their capability were tested using binary mixture gas of 70% CO₂ and 30% CH₄ via breakthrough studies using volumetric method. The experimental data were collected by manipulating the adsorption and desorption time ranging up to 4 minutes. The results show that CO₂ gas had higher affinity than CH₄ for these adsorbents. Adsorbent saturation period declined towards increasing pressure and vice versa. Experimental data showed that activated carbon made from palm kernel shell yielded the optimum purity and recovery of CH₄ and CO₂ gases. Purity of CO₂ of 94% was successfully achieved at recovery of CH₄ and CO₂ of 94% and 89% respectively. The other adsorbents were saturated quickly and less effective for high carbon dioxide content separation.