Thermodynamic and technoeconomic feasibility assessment on liquefaction of CO2 by-product of Afyon biogas power plant

The composition of the biogas produced in Afyon biogas power plant is approximately as follows: 55% CH4 (methane) - 40% CO2 (carbon dioxide)- 4.5% H2O (water) and trace amounts of other components. The methane produced is used in gas engines to generate electricity. Carbon dioxide, however, increases greenhouse gas emissions when released into the atmosphere. The model designed in this study includes the liquefaction and storage of CO2 and the technoeconomic analysis of this process. The analysis was performed in the Aspen Plus software, which is widely used in the analysis of complex processes involving numerious chemical reactions. According to the results of the thermodynamic analysis, the energy efficiency, exergy efficiency, net electrical power and liquid CO2 production rate of the plant were determined as 14.92%, 13.08%, 4,000 kW and 99 kg/h, respectively. According to the results of the technoeconomic analysis, unit electricity cost, liquid CO2 flow cost and TCC (total capital cost) are 77.5 $/MWh, 993.68 $/h and 47,548,200 $ respectively. The designed model has the potential to prevent the release of CO2 into the atmosphere at reasonable prices.