乙烯分离与复叠制冷系统用能的综合优化  

Integrated optimization of ethylene separation process and cascade refrigeration system

作　　者：张小锋 湛世辉 冯霄[1] 

机构地区：[1]中国石油大学(北京)新能源研究院，北京 102249

出　　处：《化工进展》2015年第12期4191-4197,共7页Chemical Industry and Engineering Progress

基　　金：国家重点基础研究发展计划项目(2012CB720500)

摘　　要：乙烯装置的分离过程要在低温下进行,由乙烯制冷系统提供所需冷量。乙烯制冷系统为封闭式循环,独立于分离单元之外。将乙烯分离单元与制冷系统同时优化,能有效提高装置用能效率。复叠式制冷级数是当前乙烯工业中使用最为广泛的制冷技术。本文针对乙烯分离过程和配套的复叠制冷系统,采用Aspen Hysys进行模拟并进行分析,发现系统主要的?损失发生在换热与压缩两部分,其占总损失的83%,为节能的重点。进而通过夹点技术对冷剂配置进行分析,发现-56℃以上各温位的冷量配置不合理,远超过理论最小值,-56℃以下各温位的冷量基本达到理论最小值。提出了采用多股流换热器的换热网络理论设计方法,并对冷剂进行重新配置,该理论方案可以降低丙烯制冷压缩机约30%的功耗,并节约部分乙烯制冷压缩机功耗,显著降低了乙烯深冷分离能耗。The separation process of an ethylene plant should be operated at low temperature,and a refrigeration system supplies the cooling demand. The refrigeration system in an ethylene plant is a closed cycle system independent of the separation process. The energy efficiency can be effectively improved if the separation process and refrigeration system are optimized simultaneously. Cascade refrigerating systems are most widely used in ethylene plants. In this paper,Aspen Hysys is used to simulate and analyze an ethylene separation process with a cascade refrigerating system. The exergy analysis showed lower efficiency of heat exchanger and compressor sections,whose exergy loss contribute 83% of the whole loss of the system. So energy conservation work should focus on the two sections. Then pinch technology is used to analyze refrigerant configuration. It is found that refrigerant usage above-56℃ is far more than the theoretical minimum quantity,and refrigerant usage below-56℃ is reasonable. A novel design method by using multi-pass exchangers for heat exchanger networks is proposed and the refrigerant usage is reconfigured. The new design can reduce about 30% propylene compressor work and some ethylene compressor work consumption,reducing the energy consumption of the ethylene separation significantly.

关 键 词：系统工程 [火用] 优化设计 夹点技术 乙烯 复叠制冷 

分 类 号：TQ021.8[化学工程]