Thermoeconomic cost analysis on operation strategies of gas turbine combined cycle under off-design conditions
Zhen Wang, Liqiang Duan, Zuxian Zhang
Abstract
In this paper, the thermoeconomic cost model of a typical gas turbine combined cycle (GTCC) system is established based on the structure theory of thermoeconomics. Because the operation strategy is the basis of the research on the design/off-design condition of GTCC unit. Therefore, the GTCC thermoeconomic performances with different strategies using the inlet guided valve (IGV) control are compared based on the GTCC cost model to analysis the influence of the main parameters on the unit thermoeconomic cost of each component. The variation rules of the thermoeconomic performances of the GTCC unit under design/off-design operating conditions influenced by the operating strategy and ambient temperature are revealed. The results show that the GTCC with the IGV T3-650-F operation strategy has the lowest thermoeconomic cost. Changing the operation strategy of gas turbine (GT) can reduce the generator (GEN) unit thermoeconomic cost. And higher GT inlet/outlet temperature is helpful to reduce the thermoeconomic cost of combined cycle under off-design conditions. The investment on the steam turbine (ST) and the irreversibility of the combustion chamber (CC) have the important influence on the thermoeconomic cost of GTCC system. Reducing the air compressor (AC) inlet air temperature can reduce the thermoeconomic cost of GTCC system.