Simulation and multi-aspect analysis of a novel waste heat recovery process for a power plant producing electricity, heating, desalinated water, liquefied carbon dioxide, and natural gas

Abstract

This paper presents a novel multigeneration framework based on fossil fuels, which offers several advantages such as high thermodynamic efficiency, low electricity and liquid carbon dioxide (CO2) production costs, and significantly reduced pollutant emissions. The simulation was carried out using the Aspen HYSYS software. The thermodynamic analysis revealed that the process achieves a total exergy efficiency of 86 % and an energy efficiency of 31.36 %. The integrated system yields various products, including 597.6 kmol/h of liquid CO2, 3484 kmol/h of desalinated water, 17,600 kmol/h of natural gas for the trunk line, and 41742.1 kW of power. The analyses further demonstrated that the total exergy destruction in the process amounts to 118071 kW, with contributions from the HPGU, NHPGU, MNPGU, and CSLU units of 30.1 %, 22.23 %, 30.36 %, and 17.29 %, respectively. Regarding environmental impact, the analysis revealed that the indirect emissions from the process are negligible. When the CO2 recovery rate exceeds 99 %, the direct emission amounts to 153.72 kg/h, and the pollution intensity of the proposed scheme is 3.68 gCO2/kWhel, which is lower than that of other technologies. Additionally, the economic analysis indicated that the production costs of CO2 and electricity in the proposed process are 0.075 $/kgCO2 and 0.048 $/kWh, respectively.