Study of an integrated gas turbine -Molten carbonate fuel cell-organic Rankine cycle system with CO2 recovery.

• A novel integrated gas turbine, MCFC and ORC system with CO 2 recovery is proposed. • The exergy utilization diagram (EUD) methodology is applied to reveal the energy conversion process more clearly. • The temperature matching of the new system is optimized in this paper. • When the CO 2 capture rate is 0.85, the thermal efficiency of the new system is 62.34% and the exergy efficiency is 60.08%. A huge amount of energy is consumed by recovering CO 2 in the gas turbine (GT) exhaust gas with the traditional method because of the low CO 2 concentration. A new system integrated with gas turbine, MCFC and ORC with CO 2 capture is proposed in this article. CO 2 in the gas turbine exhaust gas is concentrated by the MCFC electrochemical reaction. Compared with traditional CO 2 capture methods, it effectively decreases the energy consumption of CO 2 capture. The mid-temperature exhaust gas heat is recovered by two stages organic Rankine cycle systems. The influences of the major parameters on the new system performance are deeply studied. Also, the thermal and economic performances of the new system are compared with those of the reference system without CO 2 capture and with CO 2 capture based on the traditional mono-ethanol ammine (MEA) method. The results show that, when the CO 2 capture rate is 0.85, the thermal efficiency of the new system is 62.34%, 3 percentage points higher than that of the gas steam combined cycle system without CO 2 capture; and the exergy efficiency is 60.08%, 2.47 percentage points higher than that of the gas steam combined cycle system without CO 2 capture. Its economic performance will be improved with the reduction of the MCFC cost in the future. [ABSTRACT FROM AUTHOR]