摘要
精馏是化工过程中重要的耗能设备,其产品温度的改变将影响换热网络的集成。针对二甲苯分离吸附的实际生产过程,利用复合曲线系统分析精馏塔DA604塔压增大至170k Pa及230k Pa后塔顶和塔底产品流股温度改变对换热网络的集成和公用工程消耗量的影响,可实现精馏塔操作与换热网络的同步集成,相较与之前只考虑流股温位对换热网络的影响更加全面。结果表明,该精馏塔的塔压由110k Pa增至170k Pa时,系统的冷却公用工程用量增大1765.0k W,加热公用工程量减少1948.5k W,无需消耗加热公用工程;压力由110k Pa增加至230k Pa时,系统冷却公用工程用量增大4964.1k W,加热公用工程用量节省共计8172.4k W,此时加热公用工程用量减小为0且可在高温段向外界供给6223.9k W热量。该分析结果与夹点法的计算结果相同,由该结果可得普适性结论,当精馏塔塔顶塔底出口物流均为源时,增大塔压,系统加热公用工程减小,冷却公用工程增加,整体上有利于系统的节能。
Distillation is an important energy-consuming device of chemical process. Temperature variation of its products affects integration of heat exchange network. For the xylene separation process,the effect of distillation column＇s operating pressure was studied in this work. When the pressure of column DA604 increased to 170 k Pa and 230 k Pa,respectively,the composite curve was constructed and used to analyze variation of the pinch and minimum utility consumption. When the pressure increased from 110 k Pa to 170 k Pa,the pinch kept unchanged; heating utility decreased by 1948.5k W,while cooling utility increased by 1765.0k W. When the pressure increased from 110 k Pa to 230 k Pa,coolinging utility increased by 4964.1k W,while heating utility decreased by 8172.4k W. Namely,the heat demands can be saved and recovered heat by 6223.9k W. The results were the same with those calculated by the pinch analysis method. So when increasing the pressure of a distillation column whose top and bottom products are both sources,heating utility will decrease while cooling utility will increase. It is beneficial for energy saving of the system.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2016年第4期1062-1067,共6页
Chemical Industry and Engineering Progress
基金
国家自然科学基金项目(21476180)
关键词
精馏
换热网络
集成
夹点
distillation
heat exchange network
integration
pinch
