Organic Rankine cycle is characteristic of simplicity

safety and stability and so on. However

high cost and low efficiency are the main factors for impeding its application. This study proposes a zeotropic organic Rankine cycle(ORC) system based on liquid-separation condensation and multi-pressure evaporation(LMZORC). Mathematical programming optimization model is established and the advantages of this new cycle are verified by case study. The results show that the net power output of the proposed LMZORC is 5.05%~13.15% higher than that of the basic ORC. In addition

the dryness of liquid-separation has a significant impact on the net power output of the LMZORC system. And in the studied working fluids

there is an optimal liquid-separation dryness to maximize net power output of the system. Furthermore

for the LMZORC system

when the temperature glide is almost equal to the temperature rise of cooling water

or the temperature glide is less than the temperature rise of the cooling water and the working fluid temperature glide is maximum

the maximum net power output can be obtained. Besides

the net power output of this proposed composition adjustment system with multi-pressure evaporation is nearly 2% more than that without liquid-separation. This study has initially validated the advantage of LMZORC

which has great value for the application of this cycle in the future.