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

doi:10.11949/0438-1157.20190948

Abstract

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:

TQ 021.8

Baohong LI, Jiwen LI. New method for heat exchanger network retrofit using heat exchanger load diagram[J]. CIESC Journal, 2020, 71(3): 1288-1296.

李保红, 李继文. 采用换热器负荷图指导换热网络改造的新方法[J]. 化工学报, 2020, 71(3): 1288-1296.

Figures/Tables 14

Fig.4 HELD of the paper mill

Fig.1 Maximum heat transfer load criterion represented by HELD

Fig.2 Rule 2 represented by HELD

Table 1 Stream data of the paper mill

流股名称	实际温度/℃		热负荷 Q/kW	热容流率 FC_p/(kW/℃)	虚拟温度/℃
流股名称	T_s	T_t	热负荷 Q/kW	热容流率 FC_p/(kW/℃)	T_s*	T_t*
WW高温段	58	39.9	7951	439.3	53	34.9
WW低温段	39.9	30	1283	129.6	34.9	25
RC	60	30	2254	75.1	55	25
EX1^①	80	40	10216	255.4	70	30
EX2^①	80	40	10216	255.4	70	30
PS	70	20	7523	150.5	65	15
BW	11	61	10745	214.9	16	66
HW	50	61	2032	184.7	55	66
OI	30	50	727	36.4	35	55
BB	20	80	3763	62.7	30	90
PV	20	125	4946	47.1	30	135
RP	11	60	6306	128.7	16	65

Fig.3 Grid diagram representation of the existing HEN

Fig.5 Simplified HELD of the paper mill

Fig.6 Simplified HELD of retrofit 1 for the paper mill

Fig.7 Grid diagram of HEN retrofit 1

Fig.8 Simplified HELD of retrofit 2 for the paper mill

Fig.9 Grid diagram of HEN retrofit 2

Fig.10 Simplified HELD of retrofit 3 for the paper mill

Fig.11 Grid diagram of HEN retrofit 3

Table 2 Variation rate of heat transfer area of heat exchangers under different retrofit scenarios

换热器编号	换热面积变化率/%
换热器编号	方案1	方案2	方案3
C3	-22.3	-22.3	-17.9
C4	-2.6	-12.4	-8.8
E1	12.5	12.5	0
E2	82.9	17.0	0
H1	—	-62.9	-73.0
H2	0	—	-45.7

Table 3 Changes of heat exchangers under different retrofit scenarios

方案编号	新增换热器/个	利用的旧换热器/个	改造换热器/个	换热器总数/个
1	1	3	1	14
2	2	4	1	15
3	2	2	2	16

References 25

1	王文堂.化工技术节能手册[M].北京:化学工业出版社,2011.
	Wang W T.Manual of Energy Conservation in Chemical Technology[M].Beijing:Chemical Industry Press,2011.
2	Law R,Harvey A,Reay D.Opportunities for low-grade heat recovery in the UK food processing industry[J].Applied Thermal Engineering,2013,53:188-196.
3	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 X W,Luo X,Ma H G.Studies on the retrofit feasibility of heat exchanger networks[J].Energy Conservation,2013,32(3):12-15．
4	Briones V,Kokossis A．A new approach for the optimal retrofit of heat exchanger networks[J].Computers & Chemical Engineering,1996,20(96):S43-S48．
5	Smith R.Recent developments in process integration design techniques[C]//International Process Integration Jubilee Conference.Sweden,2013.
6	王彧斐,冯霄.换热网络集成与优化研究进展[J].化学反应工程与工艺,2014,30(3):271-280.
	Wang Y W,Feng X.Advances in heat exchange network integration and optimization[J].Chemical Reaction Engineering and Process,2014,30(3):271-280.
7	刘新文,罗行,马虎根.两种换热网络综合优化方法对比研究[J].上海理工大学学报,2015,37(3):238-244.
	Liu X W,Luo X,Ma H G.A comparative study of two comprehensive optimization methods for heat exchanger networks[J].Journal of Shanghai University of Technology,2015,37(3):238-244.
8	霍兆义,赵亮,尹洪超.基于分级超结构的换热网络改造优化[J].热科学与技术,2016,15(1):19-25.
	Huo Z Y,Zhao L,Yin H C.Renovation and optimization of heat exchanger networks based on hierarchical superstructure[J].Thermal Science and Technology,2016,15(1):19-25.
9	蒋宁,韩文巧,郭风元,等.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(8):2935-2941.
	Jiang N,Han W Q,Guo F Y,et al.Heat exchange network improvement based on actual heat load distribution[J].Chemical Industry and Engineering Progress,2018,37(8):2935-2941.
10	蒋宁,谢小东,范伟,等.数据驱动的固定拓扑结构换热网络优化改造方法[J].化工进展,2019,38(10):4452-4460.
	Jiang N,Xie X D,Fan W,et al.Data-driven fixed-topology heat exchanger network optimization method[J].Chemical Industry and Engineering Progress,2019,38(10):4452-4460.
11	Čuček L,Boldyryev S,Klemeš J J,et al.Approaches for retrofitting heat exchanger networks within processes and Total Sites[J].Journal of Cleaner Production,2019,211:884-894.
12	Akpomiemie M O,Smith R.Retrofit of heat exchanger networks with heat transfer enhancement based on an area ratio approach[J].Appl. Energy,2016,165:22-35.
13	Wan Alwi S R,Manan Z A.STEP-A new graphical tool for simultaneous targeting and design of a heat exchanger network[J].Chemical Engineering Journal,2010,162:106-121.
14	Lai Y Q,Manan Z A,Wan Alwi S R.Simultaneous diagnosis and retrofit of heat exchanger network via individual process stream mapping[J].Energy,2018,155:1113-1128.
15	Li B H,Chang C T.Retrofitting industrial heat exchanger network based on pinch analysis[J].Industrial & Engineering Chemistry Research,2010,49(8):3967-3971.
16	Yong J Y,Varbanov P S,Klemes J J.Heat exchanger network retrofit supported by extended grid diagram and heat path development[J].Applied Thermal Engineering,2015,89:1033-1045.
17	Gadalla M A.A new graphical method for pinch analysis applications: heat exchanger network retrofit and energy integration[J].Energy,2015,81:159-174.
18	Bonhivers J C,Alva-Argaez A,Srinivasan B,et al.New analysis method to reduce the industrial energy requirements by heat-exchanger network retrofit(Part 2): Stepwise and graphical approach[J].Applied Thermal Engineering,2017b,119:670-686.
19	冯霄,王彧斐.化工节能原理与技术[M]. 第4版. 北京: 化学工业出版社,2015.
	Feng X,Wang Y F.Principles and Technologies of Chemical Energy Conservation[M].4th ed.Beijing:Chemical Industry Press,2015.
20	Kemp I C.Pinch analysis and process integration-a user guide on process integration for the efficient use of energy[J].Journal of Cleaner Production,2016,110:203
21	Li B H,Chota Castillo Y E,Chang C T.An improved design method for retrofitting industrial heat exchanger networks based on pinch analysis[J].Chemical Engineering Research and Design,2019,148:260-270.
22	王春花,华贲.换热网络优化设计方法及多换热网络能量集成的研究进展[J].石油化工设备,2009,38(5):50-57.
	Wang C H,Hua B.Research progress in optimization design methods of heat exchanger networks and energy integration of multi-heat exchanger networks[J].Petrochemical Equipment,2009,38(5):50-57.
23	Linnhoff B,Hindmarsh E.The pinch design method for heat exchanger networks[J].Chem. Eng. Sci.,1983,38(5):745-763.
24	Sama D A,Qian S,Gaggioli R.A common-sense second law approach for improving process efficiencies[C]//Proceedings of the International Symposium on Thermodynamics Analysis and Improvement of Energy Systems.Beijing,1989:520-531.
25	Lal N S,Walmsley T G,Walmsley M R W,et al.A novel heat exchanger network bridge retrofit method using the modified energy transfer diagram[J].Energy,2018,155:190-204.

[1]	Xin YANG, Wen WANG, Kai XU, Fanhua MA. Simulation analysis of temperature characteristics of the high-pressure hydrogen refueling process [J]. CIESC Journal, 2023, 74(S1): 280-286.
[2]	Cheng CHENG, Zhongdi DUAN, Haoran SUN, Haitao HU, Hongxiang XUE. Lattice Boltzmann simulation of surface microstructure effect on crystallization fouling [J]. CIESC Journal, 2023, 74(S1): 74-86.
[3]	Shuangxing ZHANG, Fangchen LIU, Yifei ZHANG, Wenjing DU. Experimental study on phase change heat storage and release performance of R-134a pulsating heat pipe [J]. CIESC Journal, 2023, 74(S1): 165-171.
[4]	Yifei ZHANG, Fangchen LIU, Shuangxing ZHANG, Wenjing DU. Performance analysis of printed circuit heat exchanger for supercritical carbon dioxide [J]. CIESC Journal, 2023, 74(S1): 183-190.
[5]	Aiqiang CHEN, Yanqi DAI, Yue LIU, Bin LIU, Hanming WU. Influence of substrate temperature on HFE7100 droplet evaporation process [J]. CIESC Journal, 2023, 74(S1): 191-197.
[6]	Mingxi LIU, Yanpeng WU. Simulation analysis of effect of diameter and length of light pipes on heat transfer [J]. CIESC Journal, 2023, 74(S1): 206-212.
[7]	Zhiguo WANG, Meng XUE, Yushuang DONG, Tianzhen ZHANG, Xiaokai QIN, Qiang HAN. Numerical simulation and analysis of geothermal rock mass heat flow coupling based on fracture roughness characterization method [J]. CIESC Journal, 2023, 74(S1): 223-234.
[8]	Zhewen CHEN, Junjie WEI, Yuming ZHANG. System integration and energy conversion mechanism of the power technology with integrated supercritical water gasification of coal and SOFC [J]. CIESC Journal, 2023, 74(9): 3888-3902.
[9]	Cong QI, Zi DING, Jie YU, Maoqing TANG, Lin LIANG. Study on solar thermoelectric power generation characteristics based on selective absorption nanofilm [J]. CIESC Journal, 2023, 74(9): 3921-3930.
[10]	Yitong LI, Hang GUO, Hao CHEN, Fang YE. Study on operating conditions of proton exchange membrane fuel cells with non-uniform catalyst distributions [J]. CIESC Journal, 2023, 74(9): 3831-3840.
[11]	Yubing WANG, Jie LI, Hongbo ZHAN, Guangya ZHU, Dalin ZHANG. Experimental study on flow boiling heat transfer of R134a in mini channel with diamond pin fin array [J]. CIESC Journal, 2023, 74(9): 3797-3806.
[12]	Ke LI, Jian WEN, Biping XIN. Study on influence mechanism of vacuum multi-layer insulation coupled with vapor-cooled shield on self-pressurization process of liquid hydrogen storage tank [J]. CIESC Journal, 2023, 74(9): 3786-3796.
[13]	Song HE, Qiaomai LIU, Guangshuo XIE, Simin WANG, Juan XIAO. Two-phase flow simulation and surrogate-assisted optimization of gas film drag reduction in high-concentration coal-water slurry pipeline [J]. CIESC Journal, 2023, 74(9): 3766-3774.
[14]	Tianhua CHEN, Zhaoxuan LIU, Qun HAN, Chengbin ZHANG, Wenming LI. Research progress and influencing factors of the heat transfer enhancement of spray cooling [J]. CIESC Journal, 2023, 74(8): 3149-3170.
[15]	Lei XING, Chunyu MIAO, Minghu JIANG, Lixin ZHAO, Xinya LI. Optimal design and performance analysis of downhole micro gas-liquid hydrocyclone [J]. CIESC Journal, 2023, 74(8): 3394-3406.