Performance evaluation of an Organic Rankine Cycle fed by waste heat recovered from CO2 capture section

Authors : Vittorio TOLA, Matthias FİNKENRATH

Pages : 225-233

Doi:10.5541/ijot.5000106929

View : 9 | Download : 6

Publication Date : 2015-03-16

Article Type : Research Paper

Abstract :Natural gas-fueled combined cycle insert ignore into journalissuearticles values(NGCC); allows to reach the best performance among power plants fed by fossil fuels, but causes considerable CO2 emissions. With the aim of reducing greenhouse gases impact, NGCC could be integrated with post-combustion CO2 removal systems, typically based on chemical solvents like amines, that cause very large net efficiency penalties insert ignore into journalissuearticles values(about 9-12 percentage points at 90% overall CO2 capture);. To reduce these high capture penalties, exhaust gas recirculation insert ignore into journalissuearticles values(EGR); has been studied. To further enhance the overall plant efficiency, the recovery of available low temperature heat from the solvent-based CO2 removal systems could be also performed. Low temperature heat is available in flue gas coolers insert ignore into journalissuearticles values(80-100°C);, in the amine reboiler water cooling insert ignore into journalissuearticles values(130-140°C); and in the splitter condenser insert ignore into journalissuearticles values(100-130 °C);. This waste thermal energy could be recovered by means of an Organic Rankine Cycle insert ignore into journalissuearticles values(ORC); that is able to convert heat into electricity efficiently even at comparably low temperatures. N-Butane was found to be as the most promising organic working fluid for the cycle operating temperatures and pressures. ORC produces additional electrical power improving the global performance of the power plant, for example, up to 1-1.5 percentage points in efficiency.
Keywords : ORC, CO2 capture, low temperature heat recovery, NGCC