The Aspen plus software was applied to establish the mathematical model for supercritical carbon dioxide brayton cycle and the thermal power system of a 600 MW unit was calculated.The effects of several factors such as compression split coefficient

turbine split coefficient

pressure ratio of the compressor

inlet temperature of the turbine and main compressor on the system cycle efficiency were analyzed.The results show that

the compression split coefficient

the pressure ratio of the compressor

the inlet temperature of the turbine and main compressor have remarkable effects on the system cycle efficiency

while the turbine split coefficient has little effect.There exists an optimal coupling value between the pressure ratio of the compressor and the compression split coefficient

which results in the highest circulation efficiency.The system circulation efficiency increases with the inlet temperature of the turbine but decreases with the rising inlet temperature of the main compressor.