Based on the characteristics of cold and hot streams in crude distillation unit (CDU), using pinch technology, the streams of the heat exchanger network (HEN) in CDU are divided into four categories:hot streams above the pinch, cold streams above the pinch, hot streams below the pinch and cold streams below the pinch. The bottlenecks of the HEN are analyzed, such as the number of cold stream is much less than that of hot stream and the heat source above the pinch is deficit while the heat source below the pinch is surplus. Therefore, an optimization strategy of HEN based on the plus/minus principle is presented in this paper. A case study of this proposed strategy is carried out in the HEN of an industrial CDU with a capacity of 5 Mt/a. Results show that the final temperature of heat-exchanged crude oil is increased by 33℃, the comprehensive energy consumption of the whole CDU is decreased by 26 MJ/t, which indicates that the energy saving effect of this proposal is significant.%根据原油蒸馏装置的冷、热物流特点,借助夹点技术将换热网络冷、热物流划分为夹点上方热物流、夹点上方冷物流、夹点下方热物流和夹点下方冷物流4个部分,分析换热网络冷物流股数少于热物流股数以及夹点上方热物流热量不足而夹点下方热物流热量过剩的瓶颈,探讨基于加减原理的换热网络优化策略.案例研究结果表明,对国内某5 Mt/a原油蒸馏装置换热网络进行优化改造,原油换热终温提高了33℃,装置综合能耗下降了26 MJ/t,节能效果显著.
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