Economic analysis of gas turbine/supercritical carbon dioxide combined cycle under different cycle configurations

Abstract

S–CO2 cycle systems have many advantages, but coupling with gas turbine power generation systems has been poorly studied. Considering the huge cold energy of LNG, it can not only be used as coolant in combined cycle system, but also the natural gas after heat exchange can be used as fuel input for combined cycle and the remaining part can be supplied to city users. In this paper, ten combined cycles were proposed for both water and LNG media, with/without intercooling process and the number of flue gas heat exchangers. A detailed analysis of the investment cost, operating income and payback period of the cycle power system is carried out by selecting the appropriate cost equation. The results show that increasing the number of flue gas heat exchangers, increasing the number of coolers and using LNG as the cooling medium can improve the energy efficiency. Cascade 9 (GT/two flue gas heat exchangers intercooled LNG tandem combined cycle system) has a maximum annual benefit of 19.59 (106$); a maximum cumulative benefit (20 years) of 204.78 (106$) for Cascade 9; Cascade 9 (GT/two flue gas heat exchangers intercooled LNG tandem combined cycle system) has a minimum payback period of 7.81 years.

Keywords

• Gas turbine
• S–CO2 cycle
• LNG
• Payback period
• Economic analysis