乙烯装置制冷系统的用能分析

通过对制冷压缩机功耗的模拟和对实际运行数据的分析,比较了乙烯装置中的复迭多级制冷系统和混合冷剂制冷系统的用能状况,分析了混合冷剂制冷的优点和不足。采用AspenPlus10.2软件模拟的结果表明,采用混合冷剂制冷技术的丙烯-混合冷剂复迭制冷系统比传统的丙烯-乙烯复迭制冷系统节省功耗4.3GJ/h,制冷压缩机损系数则从47.6%减小到43.3%,而系统效率由25.0%提高到26.6%。虽混合冷剂在换热过程中出现的气液两相流,会在一定程度上抵消其在热力学效率上的优势,但混合制冷技术用于乙烯装置仍可降低能耗、提高热力学效率。

Energy Analysis of Refrigeration System of Ethylene Unit

Cascade multistage refrigeration system and mixed refrigerant refrigeration system are usually used in deep refrigeration process of ethylene unit. Through simulation of power consumption of refrigeration compressors by using Aspen Plus 10.2 software and exergy analysis with data from actual operation, energy consumptions of both above refrigeration systems were compared. The results indicate that propylene and mixed refrigerant cascade refrigeration system consumes 4.3 GJ/h less power than propylene and ethylene cascade refrigeration system. Exergy loss coefficient of refrigeration compressor in the former case goes down from 47.6% to 43.3% and corresponding exergy efficiency increases from 25.0% to 26.6%. Although gas-liquid heat transfer of the mixed refrigerant would counteract its potential thermodynamic advantage to some extent due to the presence of gas-liquid two-phase flow, the mixed refrigeration technology for ethylene unit can still reduce power consumption and improve thermodynamic efficiency.