A geothermal-assisted layout for power production and carbon dioxide capture

Abstract

Considering the high installation cost of renewable systems and reliance on weather conditions, as well as high energy consumption in post-combustion carbon capture system, the use of the combined method can assist to achieve net-zero carbon emission. Carbon dioxide (CO2) capturing based on renewable energies is introduced as a practical emission-control tool and method to tackle environmental, economic, and social challenges. In this study, to present a novel and optimized CO2 capture system an integrated layout is presented to facile and efficient utilization of fossil fuels. This layout is comprised of two sub-sections: a combined gas and steam power production unit, and a geothermal-assisted CO2 capture unit. The presented layout is simulated and its performance is evaluated concerning exergy analysis. In addition, sensitivity analysis is carried out to show the effect of changes in some influential parameters on the overall performance of the designed layout. Obtained results show that the presented scheme obtains a total thermal efficiency of 43.11%. In addition, the heat duty in the CO2 capture section is obtained to be 3.689 MJ/kgCO2 expressing the effectiveness of the presented scheme for the CO2 post-production procedure. The exergy study demonstrates that maximum irreversibility happens in the combustion chamber (47.43%), heat exchangers (35.05%), and turbines (6.257%). Besides, sensitivity assessments declare that the natural gas flow rate and the number of stages in the stripper column are the two crucial variables that also influence other functional parameters. The overall thermal efficiency increases up to 0.4331 and heat duty in the carbon dioxide capture section decreases to 3.725 MJ/kgCO2 when the stage number in the stripper column increases from 5 to 19.