CIESC Journal ›› 2020, Vol. 71 ›› Issue (3): 1288-1296.DOI: 10.11949/0438-1157.20190948

• Process system engineering • Previous Articles     Next Articles

New method for heat exchanger network retrofit using heat exchanger load diagram

Baohong LI(),Jiwen LI   

  1. Department of Chemical Engineering, Dalian Minzu University, Dalian 116600, Liaoning, China
  • Received:2019-08-20 Revised:2019-11-05 Online:2020-03-05 Published:2020-03-05
  • Contact: Baohong LI

采用换热器负荷图指导换热网络改造的新方法

李保红(),李继文   

  1. 大连民族大学化学工程系,辽宁 大连 116600
  • 通讯作者: 李保红
  • 作者简介:李保红(1973—),男,博士,教授,libh@dlnu.edu.cn
  • 基金资助:
    国家自然科学基金面上项目(21676050)

Abstract:

At present, most graphic tools are only suitable for the design or retrofit of heat exchange networks (HEN) with the goal of saving energy. The increase of energy recovery is often accompanied by the increase of the number of heat exchange units, and the number of heat exchange units obviously affects the total equipment costs. A new method for the retrofit of heat exchanger networks by using heat exchanger load diagram (HELD) is proposed. Based on pinch analysis, selecting targeted matches and reconstructing the HELD, the problem is simplified. By shifting the heat flow curve horizontally, those cross-pinch heat loads are re-matched to reduce utility consumption, and the number of heat exchangers in the retrofitted heat exchanger network can be reduced as much as possible with the help of some heuristics. An industrial case of paper mill is retrofitted to demonstrate the effectiveness of the proposed approach. Compared with reported solutions, two new retrofit networks with similar energy saving values and fewer heat exchangers are obtained.

Key words: heat transfer, process system, optimization, retrofit, heat exchanger load diagram

摘要:

目前大部分图形工具仅适用于以节能为目标的换热网络(HEN)设计或者改造。能量回收量的增加往往伴随换热单元数的增多,而换热单元数对设备投资费有较大影响。采用换热器负荷图(HELD)提出一种系统化的换热网络改造新方法。新方法基于夹点分析,在改造区间中选择匹配目标,重新构建改造用HELD,从而简化问题;通过在水平方向上平移热流股曲线实现跨夹点负荷的重新分配,完成节能目标,并结合经验规则,尽可能减少改造后换热网络的换热器数目。以一个工业造纸厂为例,对其进行节能改造方案设计,相较于文献报道结果,得到两个节能目标值相近且换热器改动数目更少的新方案,验证了新方法的有效性。

关键词: 传热, 过程系统, 优化, 改造, 换热器负荷图

CLC Number: