关键词: 系统工程, ?, 优化设计, 夹点技术, 乙烯, 三元制冷

Abstract: The separation process of an ethylene plant should be operated at low temperature. Therefore,a compression refrigeration system is needed to provide refrigerant. A ternary refrigeration system can provide a continuous cooling curve matching very well with the process stream cooling curve,and has higher thermodynamic efficiency,lower energy consumption than a cascaded refrigerant system. In order to analyze the energy saving potential of a ternary refrigeration system,in this paper,the ternary refrigerant system in a certain ethylene plant was analyzed by exergy analysis. From the exergy grand composite curve(EGCC),it could be found that the refrigerant configuration of the ternary refrigeration system was reasonable and the total exergy loss was small. The system is classified into four sub-systems:heat exchanger,compressor,throttle valve and flash drum sub-systems. The results of exergy losses show that the total exergy loss of the ternary refrigeration system is 24238.1kW,about 90% of which concentrates on the heat exchanger and compressor sub-systems. Furthermore,the exergy losses are divided into avoidable and inevitable exergy losses,in which the total inevitable exergy loss is 13539.9kW,and the total avoidable exergy loss is 10698.2kW. The work for energy conservation should focus on reducing the avoidable exergy loss.

Key words: systems engineering, exergy, optimal design, pinch, ethylene, ternary refrigerating system