Techno-economic evaluation of the evaporative gas turbine cycle with different CO2 capture options

Abstract

The techno-economic evaluation of the evaporative gas turbine (EvGT) cycle with two different CO2 capture options has been carried out. Three studied systems include a reference system: the EvGT system without CO2 capture (System I), the EvGT system with chemical absorption capture (System II), and the EvGT system with oxyfuel combustion capture (System III). The cycle simulation results show that the system with chemical absorption has a higher electrical efficiency (41.6% of NG LHV) and a lower efficiency penalty caused by CO2 capture (10.5% of NG LHV) compared with the system with oxyfuel combustion capture. Based on a gas turbine of 13.78MW, the estimated costs of electricity are 46.1$/MWh for System I, while 70.1$/MWh and 74.1$/MWh for Systems II and III, respectively. It shows that the cost of electricity increment of chemical absorption is 8.7% points lower than that of the option of oxyfuel combustion. In addition, the cost of CO2 avoidance of System II which is 71.8$/tonne CO2 is also lower than that of System III, which is 73.2$/tonne CO2. The impacts of plant size have been analyzed as well. Results show that cost of CO2 avoidance of System III may be less than that of System II when a plant size is larger than 60MW.