Optimization of heat exchanger network retrofit based on actual heat load distribution

doi:10.16085/j.issn.1000-6613.2017-2358

Abstract

Abstract: The heat exchanger network retrofit model based on actual heat load distribution was established. The stage-wise superstructure model with non-isothermal takes into account the trade-offs between operation cost and retrofit cost involving the cost of increasing area of the existing heat exchangers, configuring new heat exchangers, repiping the streams and moving the existing heat exchangers. The differences between original heat exchanger network and structure after retrofitting were taken into account. Meanwhile, the deviations between the existing equipment area and the required area were also averted. Heat load distribution of heat exchanger network was calculated according to actual heat transfer area after the recycle of existing equipment. The genetic algorithm was applied to optimize heat exchanger network structure. Result indicated that structure of heat exchanger network after retrofitting has outstanding energy-saving benefits and more energy recovery with lower modification cost, all over a short return on investment of only 0.43 years. Moreover, the effectiveness and practicality of the proposed method were demonstrated.

Key words: heat exchanger network retrofit, genetic algorithm, heat load distribution, exchanger reassignment strategy

摘要： 采用非等温混合分流分级超结构，建立了基于实际热负荷分布的换热网络改造模型，以由改造费用和运行费用组成的年度化总成本为目标，并采用遗传算法进行求解。改造费用涉及现有换热器增加换热面积、配置新换热器、重新布置管道以及移动现有换热设备所产生的费用，充分考虑了原有换热网络经改造后结构的变化所引起的改造成本。在回用原有换热设备后，根据设备实际面积来计算换热网络的热负荷分布和温度分布，即基于实际热负荷分布对换热网络进行改造。案例研究表明，改造后的换热网络结构具有良好的节能效益，合理地再利用了原网络中的旧换热设备，并以较少的改造成本实现了较高的能量回收，投资回报期仅为0.43年，验证了所提改造方法的有效性和实用性。

关键词: 换热网络改造, 遗传算法, 热负荷分布, 面积再分配策略

CLC Number:

TQ021.8

JIANG Ning, HAN Wenqiao, GUO Fengyuan, XU Yingjie. Optimization of heat exchanger network retrofit based on actual heat load distribution[J]. Chemical Industry and Engineering Progress, 2018, 37(08): 2935-2941.

蒋宁, 韩文巧, 郭风元, 徐英杰. 基于实际热负荷分布的换热网络优化改造[J]. 化工进展, 2018, 37(08): 2935-2941.

References

[1] 吴敏, 肖武, 贺高红.基于遗传/模拟退火算法考虑压降的换热网络优化改造[J].化工进展, 2015, 34(4):1171-1177. WU Min, XIAO Wu, HE Gaohong.Retrofit of heat exchanging network considering pressure drop based on GA/SA[J]. Chemical Industry and Engineering Progress, 2015, 34(4):1171-1177.
[2] 刘新文, 罗行, 马虎根.换热网络改造可行性研究[J]. 节能, 2013, 32(3):12-15. LIU Xinwen, LUO Xing, MA Hugen. Studies on the retrofit feasibility of heat exchanger networks[J].Energy Conservation, 2013, 32(3):12-15.
[3] BRIONES V, KOKOSSIS A.A new approach for the optimal retrofit of heat exchanger networks[J]. Computers & Chemical Engineering, 1996, 20(96):S43-S48.
[4] LINNHOFF B, VREDEVELD D R.Pinch technology has come of age[J].Chemical Engineering Progress, 1984, 80(7):33-40.
[5] CIRIC A R, FLOUDAS C A.A retrofit approach for heat exchanger networks[J]. Computers & Chemical Engineering, 1989, 13(6):703-715.
[6] CIRIC A R, FLOUDAS C A.A mixed integer nonlinear programming model for retrofitting heat-exchanger networks[J]. Industrial & Engineering Chemistry Research, 1990, 29(2):239-251.
[7] YEE T F, GROSSMANN I E.A screening and optimization approach for the retrofit of heat-exchanger networks[J]. Industrial & Engineering Chemistry Research, 1991, 30(1):146-162.
[8] JEZOWSKI J, BOCHENEK R, POPLEWSKI G.On application of stochastic optimization techniques to designing heat exchanger-and water networks[J].Chemical Engineering & Processing Process Intensification, 2007, 46(11):1160-1174.
[9] REZAEI E, SHAFIEI S. Heat exchanger networks retrofit by coupling genetic algorithm with NLP and ILP methods[J].Computers & Chemical Engineering, 2009, 33(9):1451-1459.
[10] ZHANG H, RANGAIAH G P.One-step approach for heat exchanger network retrofitting using integrated differential evolution[J]. Computers & Chemical Engineering, 2013, 50(9):92-104.
[11] SREEPATHI B K, RANGAIAH G P. Improved heat exchanger network retrofitting using exchanger reassignment strategies and multi-objective optimization[J].Energy, 2014, 67(4):584-594.
[12] SREEPATHI B K, RANGAIAH G P.Heat exchanger network retrofitting:alternative solutions via multi-objective optimization for industrial implementation[M]. New York:John Wiley & Sons, Ltd., 2016:159-184.
[13] 蒋宁, 俞杭生, 韩文巧. 基于面积再分配和遗传算法的换热网络改造[J]. 化工进展, 2017, 36(8):2830-2837. JING Ning, YU Hangsheng, HAN Wenqiao. Retrofit of heat exchanger network based on exchanger reassignment and genetic algorithm(GA)[J]. Chemical Industry and Engineering Progress, 2017, 36(8):2830-2837.
[14] LIU X W, LUO X, MA H G.Retrofit of heat exchanger networks by a hybrid genetic algorithm with the full application of existing heat exchangers and structures[J].Industrial & Engineering Chemistry Research, 2014, 53(38):14712-14720.
[15] LIU X W, LUO X, KABELAC S.Optimal retrofit strategy of heat exchanger networks applied in crude oil distillation units[J]. Industrial & Engineering Chemistry Research, 2016, 55(43):11283-11290.
[16] BIYANTO T R, GONAWAN E K, NUGROHO G, et al.Heat exchanger network retrofit throughout overall heat transfer coefficient by using genetic algorithm[J]. Applied Thermal Engineering, 2016, 94:274-281.
[17] AKPOMIEMIE M O, SMITH R.Retrofit of heat exchanger networks without topology modifications and additional heat transfer area[J]. Applied Energy, 2015, 159:381-390.
[18] AKPOMIEMIE M O, SMITH R.Retrofit of heat exchanger networks with heat transfer enhancement based on an area ratio approach[J]. Applied Energy, 2016, 165:22-35.
[19] NGUYEN D Q, BARBARO A, VIPANURAT N, et al.All-at-once and step-wise detailed retrofit of heat exchanger networks using an milp model[J]. Industrial & Engineering Chemistry Research, 2010, 49(13):6080-6103.
[20] SOLTANI H, SHAFIEI S.Heat exchanger networks retrofit with considering pressure drop by coupling genetic algorithm with LP (linear programming) and ILP(integer linear programming) methods[J]. Energy, 2011, 36(5):2381-2391.
[21] YEE T F, GROSSMANN I E.Simultaneous optimization models for heat integration:Ⅱ. Heat exchanger network synthesis[J]. Computers & Chemical Engineering, 1990, 14(10):1151-1164.
[22] YEE T F, GROSSMANN I E, KRAVANJA Z. Simultaneous optimization models for heat integration:Ⅰ. Area and energy targeting and modeling of multi-stream exchangers[J]. Computers & Chemical Engineering, 1990, 14(10):1165-1184.
[23] LI G, LUO Y, XIA Y, et al.Improvement on the simultaneous optimization approach for heat exchanger network synthesis[J]. Industrial & Engineering Chemistry Research, 2012, 51(18):6455-6460.
[24] AHMAD S, PATELA E.Supertarget:applications software for oil refinery retrofit[C]//Houston, Texas:American Institute of Chemical Engineers Spring National Meeting, 1987.