Study on a novel solid oxide fuel cell/gas turbine hybrid cycle system with CO2 capture

Abstract

SUMMARY A novel solid oxide fuel cell (SOFC)/gas turbine (GT) hybrid cycle system with CO2 capture is proposed based on a typical topping cycle SOFC/GT hybrid system. The H2 gas is separated from the outlet mixture gas of SOFC1 anode by employing the advanced ceramic proton membrane technology, and then, it is injected into SOFC2 to continue a new electrochemical reaction. The outlet gas of SOFC1 cathode and the exhaust gas from SOFC2 burn in the afterburner 1. The combustion gas production of the afterburner1 expands in the turbine 1. The outlet gas of SOFC1 anode employs the oxy-fuel combustion mode in the afterburner 2 after H2 gas is separated. Then, the combustion gas production expands in the turbine 2. To ensure that the flue gas temperature does not exceed the maximum allowed turbine inlet temperature, steam is injected into the afterburner 2. The outlet gas of the afterburner 2 contains all the CO2 gas of the system. When the steam is removed by condensation, the CO2 gas can be captured. The steam generated by the waste heat boiler is used to drive a refrigerator and make CO2 gas liquefied at a lower temperature. The performance of the novel quasi-zero CO2 emission SOFC/GT hybrid cycle system is analyzed with a case study. The effects of key parameters, such as CO2 liquefaction temperature, hydrogen separation rate, and the unit oxygen production energy consumption on the new system performance, are investigated. Compared with the other quasi-zero CO2 emission power systems, the new system has the highest efficiency of around 64.13%. The research achievements will provide the valuable reference for further study of quasi-zero CO2 emission power system with high efficiency. Copyright © 2011 John Wiley & Sons, Ltd.