Optimizing the Organic Rankine Cycle Fluid for Flue Gas Energy Recovery: A Techno-Economic Analysis

Abstract

This study evaluates the thermodynamic and economic performance of various working fluids for Organic Rankine Cycle (ORC)-based energy recovery from flue gases. Initially, benzene, toluene, and pentane were analyzed, with results indicating that pentane achieved the highest power output (1862 kW) with the lowest cost ($14.69 million) at 171.6 °C. To extend the analysis, additional working fluids—including hexane, R134a, propane, and isopentane—were examined for their thermal properties and system compatibility. Their thermal efficiency, power output, and cost-effectiveness were assessed using Aspen HYSYS (Version 14) for process simulations, Aspen Capital Cost Estimator for economic evaluation, and Refprop for thermodynamic property calculations. The findings indicate that hexane improves thermal efficiency by 20 %, whereas R134a reduces environmental impact by 15 %, making them viable alternatives for sustainable ORC applications.