Thermo- economic evaluation of 300 MW coal based oxy-fuel power plant integrated with organic Rankine cycle

Abstract

Oxy-fuel combustion is currently most potential technology to reduce carbon dioxide emission from coal based power plants. This work describes thermo- economic analysis of CO2 capture technology by assessment of detailed models of a 300 MW steam generation unit, an oxygen separation unit and shock wave CO2 compression unit that are developed using Aspen HYSYS v9. The overall efficiency of the oxy-fuel combustion plant reduced by 10.98% due to implementation of air separation and CO2 sequestration systems. To reduce the efficiency penalty, the waste heat released at different portions of plant is used to boost an organic Rankin cycle for power generation. CO2 compression intercoolers and air separation unit coolers are two low grade heat sources which are utilized in ORCs. By recovering the wasted heats, the unit power consumption of oxygen production decreases from 227.3 to 214.2 kW h/t O2, power plant efficiency drop reduces about 1.51% and cost of electricity decreases from 67.03 to 64.94 €/MWh. The results indicate that proposed ORCs are thermodynamically and economically feasible to integrate with plant to increase the net efficiency.