Abstract :
[en] Persistent greenhouse gas emissions since the Industrial Revolution have driven global warming and environmental change. One of the most prominent greenhouse gas emissions in Earth's atmosphere is carbon dioxide, which accounts for over 60% of global warming. CO₂ is typically emitted by energy-intensive industries such as power plants, cement kilns, steel mills, and lime kilns. To address the detrimental effects of continuous CO₂ emissions, global energy supplies reliant on fossil fuels must be managed through efficient, cost-effective solutions. In this regard, post-combustion carbon capture has emerged as a more convenient retrofit option for existing industries. The conventional post-combustion CO₂ capture processes, such as absorption, are energy-intensive. Therefore, there is a growing and significant need to develop more sustainable and efficient CO₂ capture alternative techniques. As a result, adsorption has been quantitatively studied as a promising technology for capturing CO₂ from flue gases, potentially overcoming the energy penalty associated with amine-based processes and offering lower costs and environmental impacts. The vacuum pressure swing adsorption (VPSA) process is one of the adsorption processes that offers several practical advantages for post-combustion CO₂ capture, including lower energy consumption, reduced investment costs, minimal environmental impacts, and ease of achieving automated operation. Nevertheless, fine-tuning adsorption materials (adsorbents), process configurations, and operating conditions is essential for promoting an efficient carbon capture unit. Thus, testing different VPSA cycles like three-bed, six-step, and Two-unit, five-step, with operating conditions (2 bar adsorption pressure, 0.1 bar vacuum pressure, and a feed flow rate of 1 Nm3/h for a mixture of 15% CO2/85% N2), along with adsorbents (MOF/MIL-120 (Al) and zeolite 13X), has been conducted experimentally on a lab-scale VPSA pilot, and via ASPEN Adsorption software V14 simulation to maximize CO₂ purity and recovery in the product stream and minimize energy consumption. The best experimental results for the three-bed, six-step using MIL-120 (Al) delivered a CO2 purity of 94.14%, a recovery of 90.13%, and a unit productivity of 81.25 kgCO2/(m3ads.h), while zeolite 13X achieved a CO2 purity of 80.7%, a recovery of 92.03%, and a unit productivity of 78.33 kgCO2/(m3ads.h). On the other hand, the optimal simulation results for the two-unit, five-step VPSA process using zeolite 13X resulted in a CO2 purity of 95.11%, a CO2 recovery of 90.22%, a unit productivity of 56.34 kgCO2/(m3ads.h), and an electrical energy consumption of 0.25 kWh/kgCO2.
