Corresponding author: Dr. Zuwei Liao Email: [email protected]

Subscriber access provided by READING UNIV

Article

Heat Transfer Blocks Diagram: A Novel Tool for Targeting and Design of Heat Exchanger Networks inside Heat Integrated Water Allocation Networks Xiaodong Hong, Zuwei Liao, Jingyuan Sun, Binbo Jiang, Jingdai Wang, and Yongrong Yang ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.7b04315 • Publication Date (Web): 02 Jan 2018 Downloaded from http://pubs.acs.org on January 3, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Sustainable Chemistry & Engineering is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

Corresponding author: Dr. Zuwei Liao Email: [email protected]

Mailing address (all authors): Xihu District, Zheda Road 38, Teaching Building 10, Room 5023 Hangzhou, Zhejiang 310027, P.R. China

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Heat Transfer Blocks Diagram: A Novel Tool for Targeting and Design of Heat Exchanger Networks inside Heat Integrated Water Allocation Networks

Xiaodong Hong1, Zuwei Liao1,*, Jingyuan Sun1, Binbo Jiang2, Jingdai Wang1, and Yongrong Yang1

1

State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, P.R. China 2

Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, P. R. China

Sustainability is essential for process industries, as energy and resource are getting scarcer and scarcer. For the last decade, heat integrated water allocation networks (HIWANs) have drawn more and more attention, owing to the efficient utilization of water and energy. In this paper, a systematic procedures for the synthesis of heat exchanger networks (HENs) in HIWANs has been proposed. A graphical tool, namely heat transfer blocks diagram, is developed to improve the conceptual understanding for the implications of HEN structures in HIWANs. The minimum hot / cold utility consumption can be obtained by analyzing heat surpluses and heat deficits between cold stream and hot stream heat transfer blocks, while heat


Page 2 of 41

Page 3 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


transfer matching blocks are introduced to deal with the heat exchange matches. Not only simplex series or parallel structures but also hybrid structures can be obtained via this graphical tool. Besides, a heuristic of step by step maximizing the heat load of heat exchangers is presented to guide the heat transfer matching blocks to the lower investment cost direction. Cost-effective HENs have been identified by the proposed systematic procedures. Two examples are illustrated to demonstrate the operability and availability of the systematic procedures.

Keywords: heat integrated water allocation networks, heat exchanger networks, series – parallel hybrid structure, heat transfer blocks.

Introduction Process integration is an important and efficient tool to save resources and reduce energy consumptions in process industries, where water and energy are two major needs. As problems of water scarcity and energy shortage are increasingly serious, much attentions have been paid to the synthesis of water allocation networks1-3 (WANs) and heat exchanger networks4-6 (HENs), aiming to reduce water and energy consumption. However, water and energy are inextricably intertwined in process industries, the utilization of water and energy should be considered simultaneously, which is frequently related to the synthesis of heat integrated water allocation networks (HIWANs). A latest comprehensive review has been contributed by Ahmetović et al.7.



The design methodology of HIWANs can be classified into two categories: conceptual design and mathematical programming, which are both widely investigated. Generally, mathematical programming methods consist three steps: the synthesis of a superstructure, the model development, and the model solving8. During the past decades, various superstructures have been proposed using either sequential9-11 or simultaneous12-23 approaches. Although mathematical programming methods are outstanding to solve the overall synthesis problem, the model can be complex, especially for large-scale problems. Besides, obtaining a global optimum solution or even a good local optimum is still a challenging task. One can refer to Ahmetović et al.7 for more details about mathematical programming methods. Conceptual design represents a conceptual and graphical approach, it is generally based on physical insights and heuristics. Since it is a sequential solution method in nature, the optimal trade-offs between investment cost and operating cost cannot be established. Consequently, it usually leads to sub-optimal solutions. Despite the limitations, it has the advantages of process insights. Besides, it would not cause the heavy computation burden, compared to mathematical programming methods. The conceptual design of HIWANs was initiated by the research group in Manchester24-28. A two stage procedure was introduced to simultaneously minimize energy and water in two different situations: no water re-use26 and maximum water re-use27. In the first stage, the new grid representation of Two-dimensional Grid Diagram was developed for the synthesis of WAN. In the second stage, the separate systems approach based on the composite curve in the T-H diagram was adopted to design the HEN. Later,


Page 4 of 41

Page 5 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Leewongtanawit and Kim28 proposed a Water Energy Balance Diagram to improve energy recovery in water reuse network. A new separate systems generation approach was applied to minimize heat exchanger areas. In addition to the approaches for mass transfer-based systems, Manan et al.29 developed a novel graphical tool, termed as Heat Surplus Diagram, to guide water and energy reduction simultaneously, which was applicable to both mass transfer-based and non-mass transfer-based water-using operations. Subsequently, Wan Alwi et al.30 presented a graphical approach named Superimposed Mass and Energy Curves (SMEC) to guide design towards the minimum utility targets with six design heuristics, by superimposing source and demand allocation curves and Heat Surplus Diagram on a plot of flowrate versus mass load/temperature. Besides, Luo et al.31-32 discussed different types of non-isothermal mixing’s effect on the energy performance of the water-using network and proposed some mixing rules, which can be used to simplify the HEN and improve the system’s energy performance. Hou et al.33 built a Temperature and Concentration Order Composite Curves (TCOCC) to solve both single and multiple contaminant problems, based on the concentration potential concept34. Recently, they35 extended the method to the non-mass transfer-based systems with both single and multiple contaminants, based on a single-temperature-peak design principle. It can be seen that most of conceptual design methods focused on the synthesis of WANs, in order to simultaneously

reduce

freshwater

and

utility

consumption,

such

as

the

Two-dimensional Grid Diagram27, the Water Energy Balance Diagram28, Heat Surplus Diagram29, Superimposed Mass and Energy Curves30, and Temperature and



Concentration Order Composite Curves33. However, if we focus on the graphical methods for the synthesis of HENs, only two main categories can be found. They are the separate systems approach26-28 on the T-H diagram and the matching composite curve36 on the H-F diagram. These two methods to find the heat exchange matches are based on temperature intervals and streams respectively, which result in series and parallel structures respectively. However, they only cover simplex series or parallel structures. To include series – parallel hybrid structures, new graphical tools are needed. If we reconsider all the three related quantities: flowrate (F), temperature (T) and enthalpy (H), there does remain one opportunity: T-F diagram. Although this diagram has been employed to guide the synthesis of WAN by Manna et al.29 and Wan Alwi et al.30, it has not been developed for HEN targeting and design. They are the objects of this paper. In this research, a new graphical tool, namely heat transfer blocks diagram, is proposed for the synthesis of HENs inside HIWANs. Each cold / hot stream is represented by a block on the diagram, which is a plot of temperature (T) versus heat capacity flowrate (FCp). The concept of heat surpluses and heat deficits, developed by Manan et al. 29 to guide non-isothermal mixing in the WAN, are adopted to target the utility consumption and guide the non-isothermal mixing in the HEN. The heat exchange matches can be identified by generating the heat transfer matching blocks on the diagram. Various schemes with different HEN structures can be obtained, including series – parallel hybrid structures. Besides, a heuristic is proposed to guide the construction of the matching blocks to the lower investment cost direction. In the


Page 6 of 41

Page 7 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


rest of the paper, we will first introduce the novel graphical tool for the synthesis of HENs based on a well-known example. Subsequently, two examples will also be illustrated for the performance of the novel methodology, including a large-scale example.

Synthesis of HEN on Heat Transfer Blocks Diagram In the newly developed diagram, heat capacity flowrate (FCp) and temperature (T) are adopted as the abscissa and the ordinate respectively. Hot and cold streams, extracted from the WAN, are all plotted by this novel graphical tool, namely heat transfer blocks diagram. Each cold / hot stream is represented by a block, as shown in Figure 1-(a), which can be obtained according to its starting temperature, ending temperature and heat capacity flowrate. The width and height of each block represent the heat capacity flowrate and the temperature range respectively. As a result, the area of each block revels the heat load of each stream. Heat exchange matches can be identified based on the heat transfer blocks. Various HENs can be obtained by constructing different heat transfer matching blocks (matching blocks for short). In the following sections, we will introduce how to generate the heat transfer blocks diagram, analyze heat surpluses and deficits to target the utility consumption, and construct the matching blocks, based on the example from Savulescu et al.27. What’s more, systematic procedures are introduced for the synthesis of HIWANs to minimize the investment cost.



Generation of Heat Transfer Blocks Diagram The stream data is extracted from the WAN in Savulescu et al.27, listed in Table 1 in decreasing order of the targeting temperature (TT) of cold streams and the starting temperature (TS) of hot streams. The modified starting (T’S) and targeting (T’T) temperature of hot streams can be obtained by subtracting the △Tmin (10℃ for this example). Then, the cold / hot streams are plotted on the heat transfer blocks diagram, according to TS / T’S and TT / T’T. The cold stream heat transfer blocks (cold stream blocks for short) and hot stream heat transfer blocks (hot stream blocks for short) are marked by blue and red blocks respectively, as shown in Figure 1-(a). Each cold / hot stream is presented by a block, rather than a line. For example, cold stream C2 and hot stream H2 are represented by rectangles ABDE and FGIJ respectively. The width of each block represents the heat capacity flowrate of the corresponding stream, while the height covers the temperature range from the starting temperature (TS) to the targeting temperature (TT) in the bottom-up direction for cold streams. On the contrary, as for hot streams, the height represents the temperature range from the modified starting temperature (T’S) to the modified targeting temperature (T’T) in the up-bottom direction. It is known that cold streams are demands which are heated up to their targeting temperatures and then flow into water-using operations with different operating temperatures, while hot streams are sources which originate from water-using operations and are cooled down before discharge. Thus, a specified cold stream demand can be split into other cold stream demands. At least one of these streams has


Page 8 of 41

Page 9 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


higher targeting temperature and at least one of these streams has lower targeting temperature than the original stream. For example, 20 kg/s cold stream C2 with the targeting temperature of 75℃ can be obtained by mixing 10 kg/s cold stream with the targeting temperature of 85℃ and 10 kg/s cold stream with the targeting temperature of 65℃. Reflected in the heat transfer blocks diagram, the rectangle ABDE can be transformed into two rectangles, as shown by the blue dashed line in Figure 1-(a). Similarly, mixing two or more hot stream sources with different starting temperatures can result in a hot stream with the specified temperature. For example, 20 kg/s hot stream with starting temperature of 90℃ can be obtained by mixing 12 kg/s hot stream H1 with starting temperature of 100℃ and 8 kg/s hot stream H2 with starting temperature of 75℃, as shown by the red dashed line in Figure 1-(a). It can be concluded that the cold stream blocks and hot stream blocks can be transformed by splitting cold stream demands and mixing hot stream sources respectively. Splitting cold stream demands would make cold stream blocks move upward, while mixing hot stream sources result in moving hot stream blocks downward, as shown in Figure 1-(a) by arrows. The new hot and cold stream blocks are shown in Figure 1-(b). When the area of a hot stream block is equal to the one of a cold stream block and the starting and targeting temperatures of the hot stream block are not smaller than the ones of the cold stream, it means the hot stream can heat up the cold stream to its targeting temperature. In the meantime, the hot stream can be cooled down to its targeting temperature too. One of the specific cases is when a hot stream block can cover a cold stream block exactly. Based on this perspective, heat exchange matches



can be obtained by identifying matching blocks on the diagram. Each heat transfer block can represents a heat exchange match, as well as a heat exchanger. Besides, for the concise visual effect, hot / cold stream blocks are represented by a whole polygon without being divided by vertical lines in the following sections.

Table 1. Stream data for the illustrated example Stream

Ts (℃)

C1

20

C2

F (kg/s)

FCp (kg/℃)

Enthalpy (kW)

100

50

210

16800

20

75

20

84

4620

C3

20

40

20

84

1680

H1

100

90

30

20

37.381

157.000

10990

H2

75

65

30

20

40

168

7560

H3

50

40

30

20

5.714

23.999

480

H4

40

30

30

20

6.905

29.001

290

T’s (℃)

TT (℃)

T’T (℃)

Cold streams Hot streams C1

100


100 H1'

H1 C2

B G

I

C3 H3

40

F

20 0

(a)

100

H1''

D

H2

60

C2'

80

T/℃

80

T/℃

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 41

A

E

200

300

Fcp / kJ/(s·℃ ℃)

J

C2'' H2'

60

C3 H3

40

H4

H4 20 400

0

100

(b)


200

300

Fcp / kJ/(s·℃ ℃)

400

Page 11 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 1. Heat transfer blocks diagram for the illustrated example.

Analysis of Heat Surpluses and Heat Deficits Before matching hot stream blocks and cold stream blocks, heat surpluses and heat deficits between cold stream blocks and hot stream blocks should be analyzed to target the utility consumption. When hot streams are above cold streams, the heat load of the polygon constructed by hot streams and cold streams is defined as a heat surplus. For example, part of hot stream H2 is above part of cold stream C3, as shown in Figure 2-(a), the polygon with the pattern of right slash shadow is a heat surplus. On the contrary, when hot streams are below cold streams, heat deficits exist, such as two polygons with the pattern of left slash shadow in Figure 2-(a). Heat surpluses and heat deficits are calculated in the up-bottom direction along the temperature axis and numbered the first stage, the second stage, and so on. To make sure heat transfers available without violating the △Tmin, hot or cold utility may be needed. Three rules are proposed to target the minimum hot / cold utility consumption:

The first stage should be heat surplus. If not, hot utility is needed to fill up the heat deficit. The last stage should be heat deficit. If not, equivalent cold utility must be consumed.

For any heat deficit stage, the sum of all heat surpluses before this stage should be larger than or equal to the sum of all heat deficits before and including this stage. If not, hot utility is needed to fill up the gap between heat surpluses and deficits.



The sum of all heat surpluses and hot utility should be equal to the sum of all heat deficits. If not, cold utility is implemented to insure the energy balance.

For the illustrated example, the first stage is a 4265 kW heat deficit, as shown in Figure 2-(a). The second stage and the third stage are a 775 kW heat surplus and a 490 kW heat deficit respectively. According to the above mentioned rules, 4265 kW hot utility and 485 kW cold utility are needed. The method to implement utility is trying to implement hot (cold) utility on one block, even when the heat deficit (surplus) is generated by more than one blocks. It can be seen that both cold streams C1 and C2 contribute to the heat deficit in the first stage, as shown in Figure 2-(a). Although there will be heat deficit remaining if the hot utility is implemented on cold stream C1, the newly generated heat surplus will be equal to the remaining heat deficit, as shown in Figure 2-(b). As a result, the target temperature of C1 decreases from 100℃ to 79.690℃. However, if the newly generated heat surplus cannot meet the requirement of the remaining heat deficit, transforming the heat deficit blocks is suggested. It will be introduced in the Case Study. Besides, the cold utility is consumed by a substream of hot stream H2, namely H2’’. The starting temperature of H2’’ declines from 75℃ to 59.355℃. Owing to these extra utilities, heat surpluses and heat deficits are exactly balanced. Thus, HENs satisfying the △Tmin can be obtained by constructing matching blocks.

Construction of Heat Transfer Matching Blocks


Page 12 of 41

Page 13 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


It is obvious that matching blocks can be constructed based on the original cold stream blocks, as well as the original hot stream blocks. When the cold stream blocks is chose to construct the matching blocks, the hot stream blocks can be transformed to be exactly the same as cold stream blocks by non-isothermal, and vice versa. Besides, other matching blocks schemes can be constructed by transforming hot or cold stream blocks. It is worth mentioning that it is not allowed to break the rules for heat surpluses and heat deficits during the transformation procedures. For example, in order to keep the heat deficit of the second stage unchanged, point P can only move on the yellow curve, as shown in Figure 2-(c). Point P’ shows one of the possible status. It can be seen that there are many matching blocks schemes available. Even when we construct matching blocks based on the original cold stream blocks, there are more than one schemes. Recalling the characteristic of the separate systems on the T-H diagram and the matching composite curve on the H-F diagram, horizontal and vertical views on combination of heat transfer blocks will achieve series and parallel structures respectively. However, instead of basing on temperature intervals (horizontal view) or streams (vertical view), we focus on heat transfer blocks (heat load) directly. Not only series structures and parallel structures but also series-parallel hybrid structures can be obtained. But how to determine the matching blocks? Since the freshwater and utility consumptions are determined in previous procedures, the total annual cost lies on the investment cost of heat exchangers. It will decrease as the investment cost decreases, and vice versa. Thus, a heuristic is proposed to guide the matching blocks to the lower investment cost direction.



Page 14 of 41

The temperature differences for all heat exchangers are given. Besides, the sum of heat load is equal to the area of all hot stream blocks (cold stream blocks). Thus, the sum of heat exchanger areas remains unchanged. However, the heat load and the area of each heat exchanger can vary from one HEN scheme to another scheme, which will result in different investment costs. The area and the investment cost13 of each heat exchanger are obtained by Eqs. 1 and 2 respectively. In this research, heat exchangers are assumed to be conventional counter-current shell-and-tube heat exchangers. A=

୕ ଴.ହ୩୛/(୫మ ℃)∗∆୘

IC = 8000$ + 1200$/mଶ ∗ A଴.଺

(1) (2)

According to the characteristic of the heat exchanger cost function (Eq. 2), it is obvious that the larger the area of the heat exchanger is, the less the cost of per square meter will be. It means that the heat exchangers with larger areas are preferred for minimizing the investment cost. Accordingly, we put forward a heuristic for minimizing the investment cost: generate the heat exchangers as large as possible. The proof of the heuristic can be found in the Supporting Information. The heuristic is implemented on the heat transfer blocks diagram as follows. We determine the matching blocks one by one: recognize the area of the largest rectangle on the heat transfer blocks diagram as the heat load of the first matching block (heat exchanger), then wipe out this rectangle and recognize the area of the largest rectangle among the remaining blocks as the heat load of the next matching block. The procedure continues until all of the heat transfer blocks are assigned to matching blocks.


Page 15 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


To demonstrate the steps of the proposed heuristic, let’s construct the matching blocks for the illustrated example. We choose to use the cold stream blocks to construct the matching blocks, since the sum of cold stream blocks is smaller than the one of hot stream blocks. As shown in Figure 2-(d), the largest rectangle covers cold streams C1 and C2 in the temperature interval of 75℃ to 20℃. The heat load of the first matching block (heat exchanger), namely HE1, is 16170 kW. Then, the second (HE2) and the third (HE3) heat exchangers are determined from the remaining blocks successively. Subsequently, the heat load, the flowrate of hot and cold streams involved in each heat exchanger, and the HEN structure can be obtained according to the matching blocks of Figure 2-(d). Each matching block is represented by different colors, corresponding to the heat exchanger in the HIWAN of Figure 3. Note that, the transformation from the hot stream blocks to the matching blocks can be achieved by non-isothermal. The heat load (Q) and the area (A) of each heat exchanger, the investment cost (IC), the utility cost (UC), and the total annual cost (TAC) of the illustrated example are compared in Table 2. Compared to the HIWAN in Savulescu et al.27, the investment cost and the total annual cost decrease 17.6% and 2.1% respectively.



Cold streams Hot streams C1 -4265kW

100

Cold streams Hot streams C1 HU: 4265kW H1

100

H1

H2

60

+1619kW C1'

80

C2

T/℃

T/℃

80

+775kW C3 H3-290kW

40

C2 -1619kW H2'

60

CU: 485kW H2'' +290kW C3 H3 -290kW

40

H4

H4

20

20 0

100

(a)

200

300

400

Fcp / kJ/(s·℃ ℃)

0

100

(b)

200

300

C1 HU: 4265kW H1 +1619kW C1'

80

C1

100

HU: 4265kW P

CU: 485kW H2'' +290kW C3 H3 -290kW

40

C1' HE3: 985kW

80

C2 P'

-1619kW H2'

60

Cold streams Hot streams

T/℃

100

C2

60 HE1: 16170kW C3

40

HE2: 1680kW

H4 20

20 0

(c)

400

Fcp / kJ/(s·℃ ℃)


T/℃

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 41

100

200

300

Fcp / kJ/(s·℃ ℃)

400

0

100

(d)

200

300

Fcp / kJ/(s·℃ ℃)

400

Figure 2. Construction of heat transfer matching blocks for the illustrated example.


Page 17 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


C3

Flowrate unit: kg/s Operation 1 40 ℃

6.905 H4 H3

4.762 8.333 C2

0.952

20 C1

Operation 2 100 ℃

11.667

Operation 4 5.714 50 ℃ 7.381 Operation 3 75 ℃

485 kW H2 H1

29.380

8.001 20.620

T=40 ℃ T=75 ℃ T=100 ℃

11.999 T=89.69 ℃T=85 ℃ T=50 ℃

4265 kW 50

T=79.69 ℃

20

20 20

20 T=50 ℃

T=40 ℃ T=85 ℃

T=75 ℃ 20

20 70

70

Freshwater F=90 T=20 ℃

Wastewater F=90 T=30 ℃

Figure 3. HIWAN for the illustrated example.

Table 2. Comparisons between the original HEN and the new HEN.

Savulescu et al.

Figure 3

#1

#2

#3

HU

CU

Q / kW

7560

7350

3925

4265

485

A / m2

1512

1470

785

763

19

Q / kW

16170

1680

985

4265

485

27


IC / $/y

UC / $/y

TAC / $/y

369236

1699570

3040806

304329

1699570

2975899


A / m2

3234

336

197

294

19

Systematic Procedures to Minimize Investment Cost In summary, there are several steps for the whole design process, as shown in the flow chart of Figure 4. First of all, the water allocation network is obtained by two-dimensional grid diagram27 or water energy balance diagram28. Then, hot and cold stream data is extracted from the WAN. Next, hot and cold stream blocks are plotted, followed by the analysis of heat surpluses and heat deficits. If the rules for heat surpluses and heat deficits are not satisfied, the minimum hot / cold utility cold utility consumption should be implemented. Besides, the other option is to redesign the WAN, since different WAN may result in different utility consumptions. When the rules are satisfied, matching blocks are generated according to the proposed heuristic. The last step is to obtain the HEN based on the matching blocks.


Page 18 of 41

Page 19 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Start

Design the water allocation network

Extract hot/cold stream data from water allocation network

Redesign the water allocation network

Generate heat transfer blocks diagram

Analyze heat surpluses and heat deficits

Calculate the minimum hot and cold utility consumptions for cold and hot streams respectively.

Choice 1 Are the rules for heat surpluses and heat deficits satisfied?

Choice 2

N

Y Construct the Heat transfer Matching blocks according to the proposed heuristic

Obtain the heat exchanger network based on the Heat transfer Matching blocks

Synthesis of HEN inside HIWAN

End Figure 4. Flow chart for the systematic procedures.



Case Study In this section, two examples are illustrated to demonstrate the applicability of the proposed method, including a large-scale example. The operation data of three example is listed in Table S1-S2 of the Supporting Information respectively. Besides, the cost and operating parameters13 can also be found in Table S3 of the Supporting Information. Note that, the △Tmin is set 10℃ for two examples.

Example 1 The first example is the above-illustrated example given by Savulescu et al.26, which is a well-known example involving four water-using operations. The heat exchanger networks are designed by the proposed method for two cases, based on the WAN obtained by Water Energy Balance Diagram28 and the WAN in our previous work36-37 respectively. Case 1 Leewongtanawit and Kim28 proposed a Water Energy Balance Diagram to improve energy recovery water reuse network. A water allocation network with less utility consumption compared to the one of Savulescu et al.27 was obtained. Three cold streams, namely C1-C3, and four hot streams, namely H1-H4, are extracted from the WAN, listed in Table S4 of the Supporting Information. The hot stream and cold stream blocks are generated in Figure 5-(a). Then, the heat surpluses and deficits are calculated successively, as shown in Figure 5-(a). According to rule 1, it is known that


Page 20 of 41

Page 21 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


3775 kW hot utility is needed for the first stage. Besides, 5 kW hot utility is needed for the third stage, owing to rule 2. The hot utility target of 3780 kW is obtained by the analysis of heat surpluses and heat deficits. In order to reduce the number of heaters, 3780 kW hot utility is implemented in the first stage, as shown in Figure 5-(b). So far, all three rules are satisfied. Next, the matching blocks are constructed based on the cold stream blocks, since the sum of cold stream blocks is less than the one of hot stream blocks. The cold stream blocks of C1’ and C2 in the temperature interval of 20~65℃ is the largest rectangle of all available rectangles, as shown in Figure 5-(b). Besides, it is found that a larger rectangle can be constructed, when the cold stream block of C3 is reshaped. 20 kg/s cold stream C3 with the targeting temperature of 40℃ can be replaced by 15.952 kg/s cold stream with the targeting temperature of 33.657℃ and 4.048 kg/s cold stream with the targeting temperature of 65℃, which is represented by moving 425 kW cold stream block of C3 to the one of C2, as shown in Figure 5-(b). The new cold stream blocks are shown in Figure 5-(c). Then, three heat exchangers are identified according to the proposed heuristic, as shown in Figure 5-(d). The heat load of these three heat exchangers are 13995 kW, 3570 kW, and 915 kW respectively. The whole HIWAN is shown in Figure 6, which includes a HEN with series-parallel hybrid structures. The results of the original HIWAN in Leewongtanawit and Kim 28 and Figure 6 are compared in Table 3, including the heat load and area of each heat exchanger, IC, UC, and TAC. Owing to the heuristic, the IC of Figure 6 decreases 4.6% compared to the one generated by the new separate



systems generation approach in Leewongtanawit and Kim28, resulting in 0.5% decrease of TAC.


100

Cold streams Hot streams C1 HU: 3780kW H1 +1144kW C1' -1139kW

100

-3775kW H1

80 C2

T/℃

T/℃

80

H2

60

+425kW C3 H3 -430kW

40

C2 H2

60

+425kW C3 H3 -430kW

40

H4

H4

20

20 0

100

(a)

200

300

Fcp / kJ/(s·℃ ℃)

400

0

100

(b)

200

300

C1 HU: 3780kW H1 +1144kW C1' -1139kW

100

80

C1 HU: 3780kW C1'

80

HE2: 3570kW

T/℃

H2

H3 +152kW C3' -157kW H4

40

20

C2' 60

HE1: 13995kW

40

C3' HE3: 915kW

20 0

(c)

Cold streams Hot streams 100

C2' 60

400

Fcp / kJ/(s·℃ ℃)


T/℃

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 41

100

200

300

Fcp / kJ/(s·℃ ℃)

400

0

100

(d)

200

300

Fcp / kJ/(s·℃ ℃)

400

Figure 5. Construction of heat transfer matching blocks for example 1 (Case 1).


Page 23 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


C3

Flowrate unit: kg/s Operation 1 40 ℃

10.238 4.762 Operation 4 50 ℃

5 4.048 C2

5.666 0.048

0.952 C1

H4 H3

Operation 3 75 ℃

15

H2 0.048 15.904 H1

Operation 2 100 ℃ T=100 ℃

34.048 T=92 ℃ T=75 ℃ T=43.657 ℃

3780 kW 50 T=82 ℃ 24.048 15.952

15.952 24.048

T=75 ℃

T=65 ℃ T=33.657 ℃ 74.048



Figure 6. HIWAN for example 1 (Case 1).

Table 3. Result Comparisons for example 1 (Case 1).

#1

#2

#3

HU

Leewongtanawit

Q / kW

7560

7350

3570

3780

and Kim28

A / m2

1512

1470

524

270

Figure 6

Q / kW

13995

3570

915

3780


IC / $/y

UC / $/y

TAC / $/y

310293

1425060

2707353

296082

1425060

2693142


A / m2

2799

714

183

270

Case 2 The second case is illustrated, based on the WAN from our previous work36. Three cold streams and four hot streams are extracted from the WAN, listed in Table S5 of the Supporting Information. According to the stream data, the cold stream blocks and hot stream blocks are plotted in Figure 7-(a), as well as the heat surpluses and deficits. Since there is a 3780 kW heat deficit in the first stage, 3780 kW hot utility is needed for cold stream C1, as shown in Figure 7-(b). Next, the matching blocks are constructed based on the cold stream blocks, which includes three blocks in total. It can be seen that the cold stream blocks of C1’ in the temperature interval of 20~82℃ and C2 in the temperature interval of 20~62℃ are the largest and the second largest rectangles respectively. Besides, the second largest rectangle will became larger after transforming cold stream blocks of C2 and C3, as shown in Figure 7-(b) and (c). 20 kg/s cold stream C2 with the targeting temperature of 62℃ and 20 kg/s cold stream C3 with the targeting temperature of 40℃ are replaced by 21.714 kg/s cold stream C2’ with the targeting temperature of 65℃ and 18.286 kg/s cold stream with the targeting temperature of 34.375℃. However, after the transformation of cold stream block of C2, the cold stream blocks of C1’ and C2 in the temperature interval of 20~65℃ become the largest one. Thus, three matching blocks are identified from the new cold stream blocks, as shown in Figure 7-(d). A HEN with hybrid structures can be obtained, as shown in Figure 8. The results of our previous research36 and


Page 24 of 41

Page 25 of 41

Figure 8 are compared in Table 4. In our previous work, H-F diagram is proposed to design HEN with parallel structures. Although the total heat load of Figure 8 and the one in our previous work36 are the same, the heat load distribution is different. The heuristic guide the heat exchange matches to the lower investment cost direction. The IC and TAC of Figure 8 decrease 1.7% and 0.2% respectively, compared to the one of our previous work36.


100

Cold streams Hot streams C1 HU: 3780kW H1 +1142kW C1' -1142kW

100

-3780kW H1

80 H2

60

T/℃

T/℃

80 +432kW

C2 C3 H3 -432kW

40

H2 60

+432kW

C2 C3 H3 -432kW

40

H4

H4

20

20 0

100

(a)

200

300

Fcp / kJ/(s·℃ ℃)

400

0

100

(b)

200

300

C1 HU: 3780kW H1 +1142kW C1' -1142kW

100

80

80 HE2: 3570kW

T/℃ H3 +189kW C3' -189kW H4

20

C2' 60

40

HE1: 13554kW

C3' HE3: 1104kW

20 0

(c)

C1 HU: 3780kW C1'

H2

40

Cold streams Hot streams 100

C2' 60

400

Fcp / kJ/(s·℃ ℃)


T/℃

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


100

200

300

Fcp / kJ/(s·℃ ℃)

400

0

100

(d)

200

300

Fcp / kJ/(s·℃ ℃)

400

Figure 7. Construction of heat transfer matching blocks for example 1 (Case 2).



Page 26 of 41

Flowrate unit: kg/s

C3

Operation 1 40 ℃

H4

5.714

16.327

Operation 4 50 ℃

4

3.673

8 H3

2.286 C2 18.041

H2

Operation 3 75 ℃

1.959

16

16

H1

Operation 2 100 ℃

C1

T=65 ℃ T=100 ℃

T=34.375 ℃

T=92 ℃ T=75 ℃

T=44.375 ℃

3780 kW 50

18.286

18.286

T=82 ℃ 21.714

21.714 50



Figure 8. HIWAN for example 1 (Case 2).

Table 4. Result Comparisons for example 1 (Case 2).

#1

#2

#3

HU

Q / kW

13020

3528

1680

3780

A / m2

2604

706

336

270

Q / kW

13554

3570

1104

3780

36

Liao et al.

Figure 8


IC / $/y

UC / $/y

TAC / $/y

301713

1425060

2698773

296669

1425060

2693729

Page 27 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


A / m2

2711

714

221

270

Comparisons and Discussions The results of case 1 and case 2 are compared with literature results in Table 5. Five of them are obtained by conceptual design methods, while the other three are generated by mathematical programming methods. Since the freshwater cost and the utility cost keep the same for all cited results, they are omitted in the table. The constraint of △Tmin=10℃ is adopted in the results of Leewongtanawit and Kim28, Liao et al.36, Bogataj and Bagajewicz9, Dong et al.13, Figure 6, and Figure 8. It can be seen that, with the same constraint, the TAC of Figure 6 is smallest, even smaller than the ones optimized by mathematical programing methods9, 13. However, the TAC of the ones from Ahmetović et al.15 and Zhou et al.20 are the best, since the trade-off between the area and the number of heat exchangers is fully considered. When we set the △Tmin to be 8℃, a network with two heat exchanger and one heater can be obtained, as shown in Figure S4 in the Supporting Information. The TAC of Figure S4 is just 0.9% larger than the best one. Although the TACs achieved with different approaches are roughly the same, it is still more advantageous to follow the method proposed in this work. This is due to the fact that the investment cost is considered when identifying matching blocks by the proposed heuristic and HENs with different structures can be generated, compared to the previous conceptual design methods. Furthermore, the advantage of the proposed method will be more significant as the scale of the problem increases, considering more involved streams in HEN and more



Page 28 of 41

HEN possibilities. Meanwhile, the complex mathematical models for large-scale problems may result in heavy computational burden. Obtaining a good solution without initial points is still challenging, while promising results can be generated by the proposed approach. This assertion can be verified by the second example in the following.

Table 5. IC and TAC comparisons for example 1.

Method

Item

IC / $/y

TAC / $/y

Leewongtanawit and Kim28

310293

2707353

Figure 6

296082

2693142

Liao et al.36

301713

2698773

Figure 8

296669

2693729

Figure S4

279972

2677032

Bogataj and Bagajewicz9

314495

2711555

Dong et al.13

341047

2738107

Ahmetović et al.15, Zhou et al.20

255897

2652957

Conceptual design

Mathematical programming

Example 2 The second example32 is the largest example in the existing literature, which consists of 15 water-using operations. The HIWAN for this example was first presented in Liu et al.38 by a hybrid method. The WAN was obtained by solving a mathematical model, which simultaneously consider water and energy consumptions.


Page 29 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Then pinch technology was applied for the synthesis of HEN. In this paper, the HEN is designed by the proposed method, based on the WAN from Liu et al.38. Cold stream and hot stream blocks are shown in Figure 9-(a), according to the extracted stream data (Table S6 of the Supporting Information) from the WAN38. Since the temperature of freshwater and wastewater are both 30℃, it is a threshold problem, where both hot utility and cold utility are necessary. It is found that there is a 4200 kW heat surplus in the last stage. Thus, 4200 kW cold utility is consumed to cool down 100 kg/s mixing hot stream from 40℃ to 30℃. Besides, 2800 kW hot utility should be used to satisfy the heat deficit in the first stage. Note that, 1400 kW hot utility is consumed when designing the WAN. The total hot utility consumption is equal to the cold utility consumption. If the 2800 kW hot utility is implement on cold stream C1, as shown in Figure 9-(b), the newly generated heat surplus cannot meet the temperature requirement of the remaining heat deficits. Therefore, before implementing cold utility, cold stream blocks of C1, C2 and C3 are transformed to two blocks, as shown in Figure 9-(c). 35 kg/s cold stream C2 with the targeting temperature of 100℃ and 15 kg/s cold stream C3 with the targeting temperature of 90℃ are replaced by 24 kg/s cold stream with the targeting temperature of 110℃ and 26 kg/s cold stream with the targeting temperature of 85℃. The hot utility is consumed by the mixing cold stream C1’, as shown in Figure 9-(d). Then, the matching blocks are generated on the new cold stream blocks. Similar to the last example, in order to generate a larger rectangle, the cold stream block of C4 is reshaped without increasing the sum of blocks, as shown in Figures 9-(d) and (e). 20



kg/s cold stream C4 with the targeting temperature of 80℃ are replaced by two streams, which are 13.33 kg/s cold stream with the targeting temperature of 85℃ and 6.67 kg/s cold stream with the targeting temperature of 70℃ respectively. The largest rectangle is the cold stream block of C1’ and C3’ in the temperature interval of 30~85℃, with the heat load of 19249 kW. The final matching blocks are shown in Figure 9-(f), consisting of four heat exchangers, one heater and one cooler, while the HIWAN is shown in Figure 10. This example was also studied in our previous research by both conceptual design36 and mathematical programming21, 39 methods. The result comparisons among four results with the same △Tmin of 10℃ are shown in Table 6. Since the utility cost and freshwater cost are all the same for Figure 10 and the literature results, only the investment cost and the total annual cost are compared. The IC of Figure 10 decrease 22.7%, 12.8%, and 8.3% compared to Liu et al.38, Liao et al.36, and Hong et al.39, while the TAC decrease 2.9%, 1.5%, and 0.9% respectively. Note that, the WAN of Figure 10 is the same as the one of Liu et al.38. However, a HEN with six heat exchangers was generated by pinch technology in Liu et al. 38. The investment cost of heat exchangers was not optimized in Liu et al.38. In our previous work36, only HEN with parallel structures can be obtained by the H-F diagram. In our recent work39, a mixed-integer linear programming model was proposed to target the simplified total annual cost. Owing to the linear assumption of heat exchanger cost formulation, the heat load of heat exchangers cannot be fully optimized. The result comparisons indicate the applicability of the proposed model for the large-scale problems.


Page 30 of 41

Page 31 of 41


120


120

C1 H1

C1 HU: 2800kW H1

C2 -2800kW

100

C2

100 C3 H3

T/℃

80

60

40

H2 +2108kW

80

H3

60

40

+4200kW 20 0

100

(a)

200

300

Fcp / kJ/(s·℃ ℃)

400

0

100


H1 100 C3' H3

T/℃

80

60

40

+280kW C4 -280kW H4 H5 +210kW C5 -210kW H6

C1' HU: 2800kW

+494kW -494kW H2

60

40

+4200kW 20 0

100

200

300

Fcp / kJ/(s·℃ ℃)

400


400

HU: 2800kW HE2: 1820kW

C3' H3

80

60

40

C4' 60

HE4: 5600kW

HE1: 19249kW

C5 HE3: 1400kW

40 CU: 4200kW

CU: 4200kW 200

C3'

80 C4' H4 H5 +210kW C5 -210kW H6

100

300


100 -494kW H2

0

200

Fcp / kJ/(s·℃ ℃)

C1'

+494kW

20

100

120

C1' HU: 2800kW

T/℃

H1

0

(d)

120

+280kW C4 -280kW H4 H5 +210kW C5 -210kW H6

CU: 4200kW

20

(c)

C3' H3

80

T/℃

H2

400


C1' -2800kW

300

120

H1 100

200

Fcp / kJ/(s·℃ ℃)

(b)

120

(e)

+280kW C4 -280kW H4 H5 +210kW C5 -210kW H6

+4200kW

20

100

C3

-2108kW +280kW C4 -280kW H4 H5 +210kW C5 -210kW H6

T/℃

H2

T/℃

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


20 300

Fcp / kJ/(s·℃ ℃)

400

0

100

(f)

200

300

Fcp / kJ/(s·℃ ℃)

400

Figure 9. Construction of heat transfer matching blocks for example 2.



Page 32 of 41

Operation 15 60 ℃ 10.00

Operation 1 50 ℃

C5

5 Operation 6 70 ℃

C3

21.00

H4 43.71 H3

Operation 10 95 ℃ Operation 12 95 ℃

3.00 30.00 C2

27.86

Operation 5 100 ℃

14.00


Operation 3 110 ℃

C1

H2

Operation 14 100 ℃

1400 kW

20.00

4.38


5.00

H5

6.67

Operation 9 80 ℃

Operation 4 90 ℃

12.00

H6

5

Operation 2 80 ℃

C4 13.33

Flowrate unit: kg/s

11.76

H1

*Process to process stream data can be found in Liu et al. (2015)

T=110 ℃ 2800 kW

T=104.848 ℃ T=95 ℃ T=80 ℃ 44.00 6.670 T=60 ℃

T=94.848 ℃ T=70 ℃

39.33 10.00

44.00 T=85 ℃

6.670 T=50 ℃

T=95 ℃

T=60 ℃

T=40 ℃ 83.33 16.67

4200 kW



Figure 10. HIWAN for example 2.

Table 6. Result Comparisons for example 2.

Liu et

Q / kW

#1

#2

#3

#4

#5

#6

HU1

HU2

CU

IC / $/y

TAC / $/y

7560

4200

4200

3780

1820

1470

2800

1400

4200

523620

4027020


Page 33 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


al.38

A / m2

1473

840

818

Liao et

Q / kW

12495

6720

6615

al.

36

2

A/m

3276

1344

1773

Hong

Q / kW

11760

5250

4200

39

2

727

364

283

/

/

/

73

4200

1820

2800

420 4200

188

/ et al.

119

3967687

441241

3944641

404743

3908143

420 1400

4200

/

A/m

2352

940

840

280

124

73

420

Figure

Q / kW

19249

1820

1400

560

2800

1400

4200

10

A / m2

3850

364

280

112

119

73

420

/

464287

/

Conclusion

This paper addresses the synthesis of HENs in HIWANs by a novel graphical tool, namely heat transfer blocks diagram. The minimum hot / cold utility consumption can be obtained by analyzing heat surpluses and heat deficits on the diagram, while HENs can be generated by constructing the heat transfer matching blocks. The novel graphical tool features two important properties. First, the temperature, the heat capacity flowrate, and the heat load of each stream are all displayed on the diagram. The mixing and splitting of streams on the diagram is visual and accessible by transforming heat transfer blocks. Second, the HEN structure depends on the combination of heat transfer blocks. The matching blocks are developed to identify heat exchange matches. Not only simplex series or parallel structures can be obtained, but also series-parallel hybrid structures. Meanwhile, a heuristic is proposed to minimize the investment cost during constructing the heat transfer matching blocks. Case study shows that HENs with better investment cost



performances can be obtained, compared to the current conceptual design methods. For the largest example, the obtained HEN is better than all published results with the same △Tmin, even the one by the mathematical programming method39.

Acknowledge

The financial support provided by the Project of National Natural Science Foundation of China (91434205 & 61590925), the National Science Fund for Distinguished Young (21525627), and the International S&T Cooperation Projects of China (2015DFA40660) are gratefully acknowledged.

Reference

1.

Bagajewicz, M., A review of recent design procedures for water networks in

refineries and process plants. Comput. Chem. Eng. 2000, 24 (9-10), 2093-2113, DOI: 10.1016/S0098-1354(00)00579-2 2.

Foo, D. C. Y., State-of-the-art review of pinch analysis techniques for water

network synthesis. Ind. Eng. Chem. Res. 2009, 48 (11), 5125-5159, DOI: 10.1021/ie801264c. 3.

Jezowski, J., Review of water network design methods with literature annotations.

Ind. Eng. Chem. Res. 2010, 49 (10), 4475-4516, DOI: 10.1021/ie901632w. 4.

Furman, K. C.; Sahinidis, N. V., A critical review and annotated bibliography for

heat exchanger network synthesis in the 20th Century. Ind. Eng. Chem. Res. 2002, 41 (10), 2335-2370, DOI: 10.1021/ie010389e.


Page 34 of 41

Page 35 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


5.

Song, R.; Tang, Q.; Wang, Y.; Feng, X.; El-Halwagi, M. M., The implementation

of inter-plant heat integration among multiple plants. Part I: A novel screening algorithm. Energy 2017, 140, 1018-1029, DOI: 10.1016/j.energy.201709.039. 6.

Song, R.; Chang, C.; Tang, Q.; Wang, Y.; Feng, X.; El-Halwagi, M. M., The

implementation of inter-plant heat integration among multiple plants. Part II: The mathematical model. Energy 2017, 135, 382-393, DOI: 10.1016/j.energy.2017.06.136. 7.

Ahmetovic, E.; Ibric, N.; Kravanja, Z.; Grossmann, I. E., Water and energy

integration: A comprehensive literature review of non-isothermal water network synthesis.

Comput.

Chem.

Eng.

2015,

82

(2),

144-171,

DOI:

10.1016/j.compchemeng.2015.06.011. 8.

Biegler, L. T.; Grossmann, I. E.; Westerberg, A. W.; Kravanja, Z., Systematic

methods of chemical process design. Prentice Hall PTR Upper Saddle River, NJ: 1997; Vol. 796. 9.

Bagajewicz, M.; Rodera, H.; Savelski, M., Energy efficient water utilization

systems in process plants. Comput. Chem. Eng. 2002, 26 (1), 59-79, DOI: 10.1016/S0098-1354(01)00751-7. 10. Liao, Z. W.; Wu, J. T.; Jiang, B. B.; Wang, J. D.; Yang, Y. R., Design energy efficient water utilization systems allowing operation split. Chin. J. Chem. Eng. 2008, 16 (1), 16-20, DOI: 10.1016/S1004-9541(08)60028-2. 11. Jagannath, A.; Almansoori, A., Sequential synthesis of heat integrated water networks: A new approach and its application to small and medium sized examples. Comput. Chem. Eng. 2016, 90, 44-61, DOI: 10.1016/j.compchemeng.2016.04.016.



12. Leewongtanawit, B.; Kim, J.-K., Synthesis and optimisation of heat-integrated multiple-contaminant water systems. Chem. Eng. Process: Process Intensification 2008, 47 (4), 670-694, DOI: 10.1016/j.cep.2006.12.018.

13. Dong, H.-G.; Lin, C.-Y.; Chang, C.-T., Simultaneous optimization approach for integrated water-allocation and heat-exchange networks. Chem. Eng. Sci. 2008, 63 (14), 3664-3678, DOI: 10.1016/j.ces.2008.04.044. 14. Bogataj, M.; Bagajewicz, M. J., Synthesis of non-isothermal heat integrated water networks in chemical processes. Comput. Chem. Eng. 2008, 32 (12), 3130-3142, DOI: 10.1016/j.compchemeng.2008.05.006. 15. Ahmetović, E.; Kravanja, Z., Simultaneous synthesis of process water and heat exchanger networks. Energy 2013, 57, 236-250, DOI: 10.1016/j.energy.2013.02.061. 16. Ibrić, N.; Ahmetović, E.; Kravanja, Z., Two-step mathematical programming synthesis of pinched and threshold heat-integrated water networks. J. Cleaner Prod. 2014, 77, 116-139, DOI: 10.1016/j.jclepro.2014.01.004.

17. Ahmetović, E.; Kravanja, Z., Simultaneous optimization of heat-integrated water networks involving process-to-process streams for heat integration. Appl. Therm. Eng. 2014, 62 (1), 302-317, DOI: 10.1016/j.applthermaleng.2013.06.010.

18. Ahmetović, E.; Ibrić, N.; Kravanja, Z., Optimal design for heat-integrated water-using and wastewater treatment networks. Appl. Energy 2014, 135, 791–808, DOI: 10.1016/j.apenergy.2014.04.063.


Page 36 of 41

Page 37 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


19. Ibrić, N.; Ahmetović, E.; Kravanja, Z., Simultaneous optimization of water and energy within integrated water networks. Appl. Therm. Eng. 2014, 70, 1097–1122, DOI: 10.1016/j.applthermaleng.2014.03.019. 20. Zhou, L.; Liao, Z.; Wang, J.; Jiang, B.; Yang, Y.; Yu, H., Simultaneous optimization of heat-integrated water allocation networks using the mathematical model with equilibrium constraints strategy. Ind. Eng. Chem. Res. 2015, 54 (13), 3355-3366, DOI: 10.1021/ie501960e. 21. Hong, X.; Liao, Z.; Jiang, B.; Wang, J.; Yang, Y., Simultaneous optimization of heat-integrated water allocation networks. Appl. Energy 2016, 169, 395-407, DOI: 10.1016/j.apenergy.2016.01.059. 22. Yan, F.; Wu, H.; Li, W.; Zhang, J., Simultaneous optimization of heat-integrated water networks by a nonlinear program. Chem. Eng. Sci. 2016, 140, 76-89, DOI: 10.1016/j.ces.2015.09.036. 23. Ghazouani, S.; Zoughaib, A.; Bourdiec, S. L., An MILP model for simultaneous mass allocation and heat exchange networks design. Chem. Eng. Sci. 2017, 158, 411-428, DOI: 10.1016/j.ces.2016.10.041. 24. Savulescu, L. E. Simultaneous energy and water minimisation. The University of Manchester, 1999. 25. Savulescu, L.; Sorin, M.; Smith, R., Direct and indirect heat transfer in water network

systems.

Appl.

Therm.

Eng.

2002,

22

10.1016/s1359-4311(02)00015-7.


(8),

981-988,

DOI:


26. Savulescu, L.; Kim, J.-K.; Smith, R., Studies on simultaneous energy and water minimisation—Part I: Systems with no water re-use. Chem. Eng. Sci. 2005, 60 (12), 3279-3290, DOI: 10.1016/j.ces.2004.12.037. 27. Savulescu, L.; Kim, J.-K.; Smith, R., Studies on simultaneous energy and water minimisation—Part II: Systems with maximum re-use of water. Chem. Eng. Sci. 2005, 60 (12), 3291-3308, DOI: 10.1016/j.ces.2004.12.036. 28. Leewongtanawit, B.; Kim, J.-K., Improving energy recovery for water minimisation. Energy 2009, 34 (7), 880-893, DOI: 10.1016/j.energy.2009.03.004. 29. Manan, Z. A.; Tea, S. Y.; Alwi, S. R. W., A new technique for simultaneous water and energy minimisation in process plant. Chem. Eng. Res. Des. 2009, 87 (11), 1509-1519, DOI: 10.1016/j.cherd.2009.04.013. 30. Wan Alwi, S. R.; Ismail, A.; Manan, Z. A.; Handani, Z. B., A new graphical approach for simultaneous mass and energy minimisation. Appl. Therm. Eng. 2011, 31 (6-7), 1021-1030, DOI: 10.1016/j.applthermaleng.2010.11.026. 31. Luo, Y.; Mao, T.; Luo, S.; Yuan, X., Studies on the effect of non-isothermal mixing on water-using network's energy performance. Comput. Chem. Eng. 2012, 36, 140-148, DOI: 10.1016/j.compchemeng.2011.07.007. 32. Luo, Y.; Liu, Z.; Luo, S.; Yuan, X., Thermodynamic analysis of non-isothermal mixing's influence on the energy target of water-using networks. Comput. Chem. Eng. 2014, 61, 1-8, DOI: 10.1016/j.ces.2014.07.004.


Page 38 of 41

Page 39 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


33. Hou, Y.; Wang, J.; Chen, Z.; Li, X.; Zhang, J., Simultaneous integration of water and energy on conceptual methodology for both single- and multi-contaminant problems. Chem. Eng. Sci. 2014, 117, 436-444, DOI: 10.1016/j.ces.2014.07.004. 34. Liu, Z.-Y.; Yang, Y.; Wan, L.-Z.; Wang, X.; Hou, K.-H., A heuristic design procedure for water-using networks with multiple contaminants. AIChE J. 2009, 55 (2), 374-382, DOI: 10.1002/aic.11693. 35. Xie, W.; Hou, Y.; Wang, Y.; Wang, J., A heuristic approach based on a single-temperature-peak design principle for simultaneous optimization of water and energy in fixed flowrate systems. Chem. Eng. Sci. 2016, 152, 323-342, DOI: 10.1016/j.ces.2016.06.018. 36. Liao, Z.; Hong, X.; Jiang, B.; Wang, J.; Yang, Y., Novel graphical tool for the design of the heat integrated water allocation networks. AIChE J. 2016, 62 (32), 670– 686, DOI: 10.1002/aic.15049. 37. Liao, Z.; Hong, X.; Jiang, B.; Wang, J.; Yang, Y., Novel graphical tool for the design of the heat integrated water allocation networks-Erratum. AIChE J. 2016, 62 (10), 3820-3821, DOI: 10.1002/aic.15348. 38. Liu, Z.; Luo, Y.; Yuan, X., Simultaneous integration of water and energy in heat-integrated water allocation networks. AIChE J. 2015, 61 (7), 2202-2214, DOI: 10.1002/aic.14823. 39. Hong, X.; Liao, Z.; Jiang, B.; Wang, J.; Yang, Y., Targeting of heat integrated water allocation networks by one-step MILP formulation. Appl. Energy 2017, 197, 254-269, DOI: 10.1016/j.apenergy.2017.04.003.



Supporting Information

Proof for the proposed heuristic. Operation data, operating parameter and cost data of examples 1 and 2. Stream data extracted from the WAN for example 1 (Case 1), example 1 (Case 2), and example 2. HIWAN for example 1 (△Tmin=8℃).


Page 40 of 41

Page 41 of 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


For Table of Contents Use Only

Synopsis: A graphical approach was proposed to guide the synthesis of heat exchanger networks in heat integrated water allocation networks.


Corresponding author: Dr. Zuwei Liao Email: [email protected]

Recommend Documents