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A numerical technique for Total Site sensitivity analysis

Peng Yen Liew a Sharifah Ra1047297dah Wan Alwi a Petar Sabev Varbanov b Zainuddin Abdul Manan a Jiriacute Jaromiacuter Klemes b

a Process Systems Engineering Centre (PROSPECT) Faculty of Chemical Engineering Universiti Teknologi Malaysia 81310 UTM Johor Bahru Johor Malaysiab Centre for Process Integration and Intensi 1047297cation e CPI 2 Research Institute of Chemical and Process Engineering Faculty of Information Technology University of Pannonia

Egyetem u 10 H-8200 Veszpreacutem Hungary

a r t i c l e i n f o

Article history

Received 19 October 2011Accepted 11 February 2012Available online 22 February 2012

Keywords

Total site problem table algorithm (TS-PTA)Total SiteHeat cascadeNumerical approachSite minimum utility targetsProcess integration

a b s t r a c t

Total Site Heat Integration (TSHI) is a methodology for the integration of heat recovery among multipleprocesses andor plants interconnected by common utilities on a site Until now it has not been used toanalyze a sitersquos overall sensitivity to plant maintenance shutdown and production changes This featureis vital for allowing engineers to assess the sensitivity of a whole site with respect to operational changesto determine the optimum utility generation system size to assess the need for backup piping toestimate the amount of external utilities that must be bought and stored and to assess the impact of sensitivity changes on a cogeneration system This study presents four new contributions (1) Total SiteSensitivity Table (TSST) a tool for exploring the effects of plant shutdown or production changes on heatdistribution and utility generation systems over a Total Site (2) a new numerical tool for TSHI the TotalSite Problem Table Algorithm (TS-PTA) which extends the well-established Problem Table Algorithm(PTA) to Total Site analysis (3) a simple new method for calculating multiple utility levels in both the PTAand TS-PTA and (4) the Total Site Utility Distribution (TSUD) table which can be used to design a TotalSite utility distribution network These key contributions are clearly highlighted via the application of thenumerical technique to two Case studies

2012 Elsevier Ltd All rights reserved

1 Introduction

Pinch Analysis is an established technology for reducing energyconsumption that has been widely applied in various industries formore than 30 years Dhole and Linnhoff [1] Raissi [2] and Klemeset al [3] extended traditional heat integration which focuses ondirect heat transfer among process streams at a single site to heatintegration for multiple sites This is known as Total Site HeatIntegration (TSHI) sometimes called ldquosite-wide integrationrdquo Directheat transfer is not always suitable for inter-process heat recoverydue to the required high degree of operational 1047298exibility and the

long-distance piping needed which makes it very costly [4] TSHIusing indirect heat transfer utilising existing utility systems istypically more cost effective because the existing plant pipingsystem can be used TSHI heat integration is linked by a commoncentral or sectional utility system

Dhole and Linnhoff [1] have introduced Site Sink and SourcePro1047297les (SSSP) a graphical tool that can be used to evaluate fuelconsumption cogeneration emissions and cooling needs foran integrated site A simple exergy model was proposed for

cogeneration capacity estimation based on SSSP and the model wasfurther extended by Raissi [2] and Klemes et al [3] Based on SSSPKlemes et al [3] developed the Total Site Pro1047297le (TSP) and the SiteUtility Grand Composite Curve which can be used to evaluate TotalSite potential heat recovery Subsequently Mareacutechal and Kalit-ventzeff [5] introduced a mathematical programming tool forminimising Total Site energy costs Their work also included anintegration of combined heat and power production using a steamnetwork Matzuda et al [6] have successfully studied the heatrecovery potential for a large steel plant using TSP analysis

An advanced approach to these concepts known as top-level

analysis is one that allows for ldquoscopingrdquo ie selecting siteprocesses to target for heat integration improvements [7] Theutility system is 1047297rst optimised for the current steam and powerdemands This is followed by an assessment of the potential bene1047297tof reducing steam demands at various levels by successively opti-mising the system in steps of steam demand reduction This resultsin a set of curves for steam marginal prices for the system underconsideration

Perry et al [8] extended the Total Site concept to a broaderspectrum of processes in addition to the industrial processA potential for the integration of renewable energy sources wasintroduced to reduce the carbon footprint of a Locally Integrated

Corresponding author Tel thorn60 07 5535533 fax thorn60 07 5581463E-mail address shashachemeutmmy (SR Wan Alwi)

Contents lists available at SciVerse ScienceDirect

Applied Thermal Engineering

j o u r n a l h o m e p a g e w w w e l s e v i e r c o m l o c a t e a p t h e r m e n g

1359-4311$ e see front matter 2012 Elsevier Ltd All rights reserved

doi101016japplthermaleng201202026

Applied Thermal Engineering 40 (2012) 397e408





Speci1047297cally at above pinch DT minpp2 is added to the shiftedtemperature in step a(i) At below pinch point DT minpp2 is sub-tracted in step b(i)

22 Tool 2 Total Site Problem Table Algorithm (TS-PTA)

The TS-PTA is a continuation of the PTA table with an extensionof four columns This table represents an algebraic version of theSite Composite Curve (SCC) in a graphical TSHI analysis Theprocedure is described as follows

a The heat sinks above the pinch region in each process areadded as lsquonet heat sinksrsquo according to utility type Similarly theheat sources below the pinch region are added to become lsquonetheat sourcesrsquo according to utility level

b The net heating requirement at each utility level is formulatedby deducting the net heat source from the net heat sink

c The net heating requirements are then cascaded from the topto the bottom

d Analogous to the PTA the most negative value of the previouscascade is then used to initiate a new cascade after 1047297rstchanging it to a positive value

e Similar steps to construct a PTA involving multiple utilities areperformed as followsi Above the Total Site Pinch the net heat requirement is

cascaded from the top to the bottom An external heatingutility is added into the system when there is a negativevalue to balance the heat de1047297cit at different utility levels

ii Below the Total Site Pinch the neat heat requirement iscascaded from the lowest temperature cooling utility to thepinch A negative external cooling utility is added whena positive value occurs in the cascade

23 Tool 3 Total Site Utility Distribution (TSUD) table

To visualise the site distribution network a TSUD table can beconstructed as follows

a The table lists the heat sources and sinks of each site accordingto utility The external heat requirement calculated in the TS-PTA is also recorded

b Arrows are used to indicate possible utility exchanges from onesite to another or from a utility plant to a site

24 Tool 4 Total Site Sensitivity Table (TSST)

The Total Site Sensitivity Table (TSST) is a practical tool foranalysing the effects of variations in Total Site operating conditions

on heat distribution and utility generation The TSST is constructedas below

a The TS-PTA is used to determine the utilities necessary fordifferent operating conditions eg when one of the plants is

shutdown The 1047297ndings are recorded in the table based on thedifferent types of utilities

b Variations of normal operation with various operating condi-tions are calculated by subtracting the utility requirements innormal operations from the utility requirements underdifferent operating conditions according to utility type

A more detailed explanation of all the tools using different stepsis described below

3 Demonstration Case study

The four tools are used to demonstrate their application to TotalSite sensitivity analysis

31 Step 1 construct the Problem Table Algorithm (PTA) to

determine QH min QC min and the pinch temperature for each

individual plant

The temperature of cold streams (T c) and the temperature of hotstreams (T h) in an individual plant are converted to shifted coldstream temperatures (T crsquo) and shifted hot stream temperatures(T hrsquo) T c is shifted by adding half of the minimum temperaturedifference between processes DT minpp whereas T h is shifted bysubtracting half of DT minpp Assuming a DT minpp of 20 C for plant A

and a DT minpp of 10

C for Plant B Tables 1 and 2 show the shiftedtemperatures of all streams in Plants A and B of Case Study1 Table 3 shows the utility temperature levels available at theplants which are used in the next step The minimum utilityprocess temperature difference DT minup is 10 C

PTA are performed for both Plant A and Plant B The completedPTAs for Plants A and B are shown in Tables 4a and 4b respectivelyAs shown in Table 4 plant A requires 2250 kW of hot utility and400 kW of cold utility with a shifted pinch temperature of 60 CPlant B requires 100 kW of hot utility and 1543 kW of cold utilitywith a shifted pinch temperature of 195 C Figs 1 and 2 are theGCCs for plants A and B The results from these GCCs are similar tothe results obtained from the PTA given in Tables 4a and 4b

32 Step 2 construct a Multiple Utility Problem Table Algorithm(MU-PTA) for each individual plant to obtain targets for multiple

utility levels as heat sources and sinks for TSHI

MU-PTA are constructed to target the amounts of various utilitylevels selected as potential sinks and sources for use in Total Site

Table 1

Stream data for Plant A of Case study 1 with DTmin frac14 20 C modi1047297ed example fromCanmet ENERGY [22]

Stream T s (C) T t (C) DH(MW) mCp (kWC) T srsquo (C) T trsquo (C)

A1 Hot 200 100 200 20 190 90A2 Hot 150 60 360 40 140 50A3 Cold 50 120 490 70 60 130A4 Cold 50 220 255 15 60 230

Table 2

Stream data for Plant B of Case study 1 with DT min frac14 10 C modi1047297ed example fromKemp [20]


B1 Hot 200 50 0450 30 195 45B2 Hot 240 100 0210 15 235 95B3 Hot 200 119 1863 230 195 114B4 Cold 30 200 0680 40 35 205

B5 Cold 50 250 0400 20 55 255

Table 3

Site utility data for Case study 1

Utility Temperature (C)

High-pressure steam (HPS) 270Medium pressure steam (MPS) 17993Low-pressure steam (LPS) 13359Cooling water (CW) 15e20

PY Liew et al Applied Thermal Engineering 40 (2012) 397 e408 399



integration The multiple utility cascade methodology is an exten-sion of the PTA with an additional 4 columns The multiple utilitycascade calculations are similar to GCCs and can be used identifypockets and target the exact amounts of utilities needed withina given utility temperature interval Note that multiple utilitycascades must be performed based on the pinch regions for eachplant that were determined in Step 1

321 Multiple utility cascades in the region above the pinch of each

individual plant

All shifted temperatures (T0) in the region above the pinch(column 1 Table 5) from Table 4 PTA are reduced by DT minpp2 toreturn them to normal temperatures and then the minimumtemperature difference between the utility and the process

(DT minup) is added as shown in column 2 Table 5 the resultingtemperature is labeled T 00 The utility temperatures listed in Table 3were also added into Table 5 to make it easier to determine theutility distribution at a later stage

Heat is again cascaded starting from the highest temperaturesegment to the pinch temperature as shown in column 7 Tables 5aand 5b Note that there are no changes in the calculations of lsquosummCprsquo and lsquosum DHrsquo for each temperature level This cascade isknown as a lsquomultiple utility heat cascadersquo it differs from theprevious heat cascade in the PTA (column 6 Tables 4a and 4b)because it is performed interval-by-interval If a negative value isencountered while cascading one of the temperatures externalutilities are immediately added at that point (the amount of external utility added is listed in column 8) equal to the negative

value The cascade then becomes zero at that temperature eg at

a shifted temperature of 190 C the cascade initially gives a valueof 600 kW at column 7 Therefore 600 kW of external utility isadded at this interval as listed at column 8 The cascade nowbecomes zero here as shown in column 7 Table 5 The cascade isthen continued and the procedure is repeated

Once the multiple utility heat cascades are completed theamounts of each type of utility consumed in the process areobtained by adding the utility consumed below the utilitytemperature (from column 8 Table 5) to before the next utilitytemperature For example Table 5a shows that 600 kW of high-pressure steam (HPS) at a temperature of 270 C is consumed inplant A between 270 C and 17993 C Thus 1650 kW of low-pressure steam (LPS) is used between 13359 and 60 C for plantA The same procedure is repeated for plant B to yield a require-

ment of 100 kW of high-pressure steam

322 Multiple utility cascades for the region below the pinch of

each individual plant

A similar methodology is used for multiple utility cascadingbelow the pinch temperature All temperatures available below thepinch are shifted by adding DT minpp2 and then subtracting theminimum temperature difference between the utility and processDT minup (see the region below the pinch in column 2 Table 5) toobtain the temperatures in the utility temperature scale Utilitytemperatures are then added to the temperature list as in column2 Table 5

However multiple utilities are instead cascaded starting fromthe bottom temperature to the pinch temperature and any positive

heat value encountered while cascading must be zeroed out by

Table 4a

Single utility cascade table for Plant A of Case study 1

1 2 3 4 5 6 7

Trsquo ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Heat

Cascade

Single

Utility

Heat

Cascade20 40 70 15

230 0 2250

40 -15 -600

190 -600 1650

50 5 250

140 -350 1900

10 45 450

130 100 2350

40 -25 -1000

90 -900 1350

30 -45 -1350

60 -2250 0

10 40 400

50 -1850 400

PY Liew et al Applied Thermal Engineering 40 (2012) 397 e408400



Fig 2 Grand Composite Curve for Plant B of Case study 1 [15]

Table 4b

Single utility cascade table for Plant B of Case study 1

1 2 3 4 5 6 7

T ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Cascade

Single

Utility

Cascade3 15 23 4 2

255 0 100

20 -2 -40

235 -40 60

30 -05 -15

205 -55 45

10 -45 -45

195 -100 0

81 215 17415

114 16415 17415

19 -15 -285

95 1613 1713

40 -3 -120

55 1493 1593

10 -1 -10

45 1483 1583

10 -4 -40

35 1443 1543

Fig 1 Grand Composite Curve for Plant A of Case study 1 [15]




generating utilities (see the lower partof column 7 and 8 inTable 5)For the region below the pinch the negative values encounteredduring multiple utility cascading represent pockets in the GCC

The amount of utility that can be generated can be determinedby adding the amounts of excess heat from above the utilitytemperature to the next utility temperature level For exampleplant A can generate 400 kW of CW using process heat between 50and 10 C For plant B 21650 kW of medium pressure steam (MPS)at 190 to 17993 C and 99631 kW of LPS between 17993 and13359 C can be generated whereas 33019 kWof CW is consumed

The proposed method differs from the one developed by Costaand Queiroz [17] The method in this study was developed througha detailed observation of multiple utility targeting in the GCC Inaddition the method proposed herein is a direct continuation of the PTA in which the multiple utility cascade actually uses most of the information from the PTA The method proposed by Costa andQueiroz [17] includes an interpolation step for 1047297nding the upperand lower temperature boundaries after utility targeting However

the proposed methodology targets utilities according to tempera-ture intervals with the utility temperatures becoming temperatureboundaries to distinguish the amounts of each utility type The

calculationsinvolved in this proposed methodare also simpler thanthose of the previously proposed method

33 Step 3 construct the Total Site Problem Table Algorithm

(TS-PTA) to determine the amounts of utilities that can be

exchanged among processes

This part is an extension of the PTA to represent the Site CC inTSHI The utilities available from each plant are arranged fromhighest to lowest temperature The utilities generated below thepinch temperature for all sites as determined in Step 3 are addedtogether to represent the net heat source (see column 3 Table 6)The utilities consumed above the pinch temperature for all sites asdetermined in Step 2 are added together to represent the net heat

sink (see column 4 Table 6) Fig 3 shows the TSP and the Site

Table 5a

PTA with multiple utility heat cascades for Plant A of Case study 1

1 2 3 4 5 6 7 8 9

Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

Heat

Cascade

Utility

Consumed

Generated

(kW)

Heat Sink

Source20 40 70 15

270 0 HPS 600

40 0 0

230 230 0

40 -15 -600 600

190 190 0

1007 5 5035

17993 5035 MPS 0

3993 5 19965

140 140 250

641 45 28845

13359 53845 LPS 1650

359 45 16155

130 130 700

40 -25 -1000 300

90 90 0

30 -45 -1350 1350

6060 0

Pinch

60 0

10 40 400-400

50 50 0

35 0 0

15 0 CW 400




Table 6

Total site Problem Table algorithm (TS-PTA) for Case study 1

1 2 3 4 5 6 7 8 9

Utility Utility Temp (C) Net heatsource (kW)

Net heatsink (kW)

Net heatrequirement (kW)

Initial heatcascade

Final single heatcascade

Multiple utilityheat cascade

External utilityrequirement (kW)

0 113719 0HPS 270 0 700 700 700

700 43719 0MPS 17993 21650 0 21650 0

48350 65369 21650LPS 13359 99631 1650 65369 43719

113719 0 (Pinch) 0CW 15e20 73019 0 73019 L73019

407 73019 0

Table 5b

PTA with multiple utility heat cascade for Plant B of Case study 1

Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

HeatCascade

Utility

Consumed

Generated(kW)

Heat Sink

Source3 15 23 4 2

270 0 HPS 100

10 0 0 0

255 260 0

20 -2 -40 40

235 240 0

30 -05 -15 15

205 210 0

10 -45 -45 45

195

200 0Pinch

190 0

1007 215 21651 -21650

17993 0 MPS 21650

4634 215 99631 -99631

13359 0 LPS 99631

2459 215 52869 -33019

114 109 -1985

19 -15 -285 0

95 90 -170

40 -3 -120 0

55 50 -50

10 -1 -10 0

45 40 -40

10 -4 -40 0

35 30 0

15 0 0 0

15 0 CW 33019




Composite Curve for Case study 1 as proposed by Varbanov et al[15] The net heat sink and the net heat source from Fig 3 are thesame as in the TS-PTA (columns 3 and 4 Table 6) The net heat sinkis subtracted from the net heat source to obtain the net heatrequirement (column 5 Table 6) The locations with negativeamounts of net heat indicate heat de1047297cits whereas the locationswith positive values indicate heat surpluses The Second Law of Thermodynamics speci1047297es that heat can only be transferred froma higher temperature to a lower temperature Therefore the heatsurplus at higher temperature utilities can be transferredto utilitieswith lower temperatures that have heat de1047297cits For example the217 kW of MPS in Case study 1 can be transferred to LPS which has

heat de1047297

cit of 654 kW instead of disposing of this excess heat withan external cooling utility As a result the net heat requirement iscascaded from top to bottom starting with an initial value of zeroThe most negative value in the initial heat cascade (column 6Table 6) is then used to determine the amount of external heating

utility needed for the system by making it positive and cascadingcolumn 5 again (see column 7 Table 6) This gives a value of 113719 kW of external heating needed The value at the bottom of the cascade represents the total cooling utility needed by thesystem which is 73019 kW The location at which the valuebecomes zero is the Total Site Pinch Point which is between the LPSand CW temperatures

Similarly to Step 2 the utilities in Table 6 can be separated intotwo parts ie the regions above and below the Total Site Pinchregion Multiple utility cascades above the Total Site Pinch point usethe same method as in Step 2(a) (see column 8 and 9 Table 6) Thenet heat requirement (column 5 Table 6) is cascaded (column 8 and9) from the top to the pinch point by assuming that there is no heatsupplied at a temperature above the HPS The same amount of external heating utility is added when there is a negative value inthe cascade eg 700kW of HPS and 43719 kWof LPS are needed inCase study 1 as heating utilities Step 2(b) is similar for the regionbelow the Total Site Pinch as shown below the pinch in columns 8and 9 of Table 6 Multiple utilities are cascaded (columns 8 and 9)from the bottom to the pinch point and cooling utility is addedwhen there is a positive value in the cascade until it reaches zeroNote that cooling utilities below the Total Site Pinch are repre-

sented by negative numbers For Case study 1 73019 kW of external cooling water (CW) is required to dispose of the excessheat

The effect of multiple utilitycascading above the Total Site Pinchin Table 6 is clearly evident in Fig 3 The heat sources at MP and LPtemperatures are provided to the heat sink at LP A heatingrequirement is necessary for LP instead of MP which is lesseconomical Fig 3 clearly shows that the heat requirement of 43719 kW also can be ful1047297lled by using Hot Water (HW) at a rangebetween 50 and 60 C

34 Step 4 construct a Total Site Utility Distribution (TSUD) table

to visualise the utility 1047298ow in the sites

The SCC does not adequately display the utility distributionwhen there are several processes involved on the integrated siteThe amounts of utility distribution for each site from on-site utilitysystems can be visualised using the TSUD table (Table 7) All the

Fig 3 TSP and SCC for Case study 1 [15]

Table 7

Total site Utility Distribution (TSUD) table for Case study 1




heat sources and heat sinks in the various plants are listed sepa-rately according to utility type as shown in columns 3 and 4 Theexternal utilities calculated from Step 4 are also listed in Table 7Arrows within the table show that heat sources can be transferredto heat sinks for the same type of utility If there are extra heatsources heat can be transferred to the lower utility levels

4 Application of the TS-PTA to TS sensitivity with changesand variations

As mentioned previously the TS-PTA can be bene1047297cial for ana-lysing the sensitivity of the TSHI to plant shutdowns due to main-tenance or upsets and to design mitigation strategies This isillustrated using Case study 2 from Perry et al [8] Here there arefour sites considered in Locally Integrated Energy Sectors (LIES)two industrial process plants a hospital complex and a combinedresidential and of 1047297ce complex The stream data for the four plantsare listed in Table 8e11 Plants A and C are assumed to have thesame DT minpp of 20 C whereas Plants B and D both have a DT minpp

of 10C Table 12 shows the types of utilities serving the area witha DT minup of 10 C

Steps 1 to 4 were performed for the processes in Case study 2The 1047297nal TS-PTA values for the standard operation of the plantscomprising the TS are listedin Table 13 Due to its numerical natureit is very convenient to manipulate data in the TS-PTA to obtain newvalues for various cases Forexample to consider a plant shutdownwe omit the contributions from the shutdown plant from the heatsinks and sources in columns 3 and 4 of Table 13 The new externalutility requirements are then obtained Table 14 summarises theexternal utility variations when one of the plants is shutdown Werefer to Table 14 as the proposed Total Site Sensitivity Table (TSST)which can be used to gain many insights into utility system designThe variance in Table 14 is calculated by subtracting the amounts of external utilities during plant shutdowns from the values neededduring normal operation A positive variance above the Total SitePinch indicates that the central utility has a heat surplus that is not

used in any sinks The utility systems have the following options

(i) Fewer utilities can be generated if permittedby the turn downratio

(ii) The heat surplus can be disposed of using an external coolingutility which would incur a penalty cost

(iii) The heat surplus can be sold to other plants(iv) For HP or MP steam if a plant has a combined heat and power

system (CHP) with a double-stage extraction turbine the heatsurplus can be used to generate extra electricity for the plant

(v) The heat surplus can be cascaded downwardsto locationswithnegative variances provided they are still located in the sameTS-PTA pinch region

A positive variance below the Total Site Pinch represents surpluscooling utility produced by the utility plant and it can be cascaded

Table 8

Stream data for Plant A [8] with DT minpp frac14 20 C

Stream T s (C) T t (C) DH (kW) mCp (kWC) T srsquo (C) T trsquo (C)

A1 Hot 170 80 5000 555556 160 70A2 Hot 150 55 6477 681818 140 45A3 Cold 25 100 1500 200000 35 110A4 Cold 70 100 1050 350000 80 110A5 Cold 30 65 5250 1500000 40 75

Table 9

Stream data for Plant B [8] with DT minpp frac14 10 C


B1 Hot 200 80 10000 833333 195 75B2 Cold 20 100 4000 500000 25 105B3 Cold 100 120 10000 5000000 105 125B4 Hot 150 40 8443 767575 145 35B5 Cold 60 110 1000 200000 65 115B6 Cold 75 150 7000 933333 80 155

Table 10

Stream data for Plant C [8] with DT minpp frac14 20 C


C1 Hot 85 40 2385 05300 75 30C2 Hot 80 40 9640 24100 70 30C3 Cold 25 55 1770 05900 35 65C4 Cold 55 85 7740 25800 65 95C5 Cold 33 60 648 02400 43 70C6 Cold 25 60 7700 22000 35 70C7 Cold 30 121 1274 01400 40 131C8 Cold 25 28 15168 505600 35 38C9 Cold 30 100 5950 08500 40 110C10 Cold 18 25 10080 144000 28 35C11 Cold 21 121 500 00500 31 131

Table 11Stream data for Plant D [8] with DT minpp frac14 10 C


D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12

Site utility temperatures


High-pressure steam (HPS) 170Steam (ST) 125Hot water (HW) 50e60Cooling water (CW) 20

Table 13

Total Site Problem Table algorithm (TS-PTA) during normal operation

Utility Utility Temp(C) Net heatsource (kW)

Net heatsink (kW)


Initial heatcascade

Final heatcascade

Multiple utilitycascade

Amount of utility needed

0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14

Total Site Sensitivity Table (TSST)

Utility Total Site external utility requirement kW

Normaloperation

Plant Ashutdown

Variance fromnormal operation

Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357

Pinch Pinch Pinch PinchCW 3515 3515 0 0 3515 3515 0 3515 0

STEP 1 Perform Problem Table Algorithm (PTA) for all individual process

STEP 2 Construct multiple utility cascade for each individual process

Above pinch temp (heat sink) Below pinch temp (heat source)

Cascade the heat available from the highest

temperature towards pinch temperature external utility

added when there is negative value in the cascade

Shift all the temperatures by deduct ∆Tminpp2 and add

with ∆Tminup

Shift all the temperatures by add ∆Tminpp2 and deduct

with ∆Tminup

Sum the external heat enthalpy below the utility

temperature until before the next utility temperature

Cascade the heat available from the lowest


added when there is positive value in the cascade

Sum the external heat enthalpy above the utility


STEP 3 Perform Total Site Problem Table Algorithm (TS-PTA)

Formulate lsquoNet heat sinkrsquo and lsquoNet heat sourcersquo by adding heat sink from above pinch region at each

processes and heat source from below pinch region according to utility level

Calculate lsquoNet heat requirementrsquo by deducting net heat source with net heat sink

Cascade the net heat requirement from top to bottom by assuming no hot utility provided

Cascade the net heat requirement from top to bottom by taking the most negative value in the

previous cascade as hot utility provided

Above Total Site Pinch Below Total Site Pinch







STEP 4 Construct Total Site Utility Distribution

(TSUD) Table

Record all the heat sinks and sources of different

processes according to types of utility Record also site

utility requirement as calculated in STEP 4

Represent the heat flows from one process to another

or from utility to a process

Application Construct Total Site Sensitivity Table

(TSST)

Omi t t h eh e a t s i nk an d s o ur c ef r om

pr o c e s s s h u t d own

Record all the utility requirement calculated in STEP 4

Calculate the variance of normal operation with

situation when one of the plant shutdown

Fig 4 Summary of the proposed methodology




upwards to serve as an extra heat source at higher temperature Anegative variance indicates the central utility has a heat de1047297cit andmore external utility must be generated Based on this de1047297cit thedesigners can determine the maximum size of utility system thatmust be built

Based on Case study 2 the following conclusions can be drawn

(i) HP - If Plant C is shutdown there will be excess HP Because allthe above pinch variance for utilities below HP (ST and HW)are also positivethis heat cannotbe cascaded downwards TheHP must be diverted for electricity generation if a CHP systemis available disposed of using cooling utilities or sold to otherplants For other plant shutdowns there is no effect on HPconsumption

(ii) ST - For ST more ST is needed if Plant A is shutdown andexcess ST is generated if Plants B C and D are shutdown Theboiler generating ST should have a maximum design capacitythat can reach 7770 kW and the boiler could be turn down to810 kW because if Plant B is shutdown part of the surplus STavailable can be cascaded downwards to satisfy the HWdemand a negative variance)

(iii) HW- For HW moreHW isneeded ifPlant A and B are shutdown

and excess HW is generated if Plant C and D are shutdownHence the boilerheater generating HW should havea maximum design capacity that can reach 6897 kWand a turndown of not more than 4863 kW If the turn down is morethan4863kW extracooling utilities will be neededor the extraHWcan be sold to other plants The HW utility requirement if PlantB is shutdown can be obtained from the surplus ST available

(iv) CW - If Plant B is shutdown there will be 35 kW of extracooling water capacity available This extra cooling water canbe used to remove the surplus heat from ST or the coolingtower can be shutdown

5 Methodology summary

Fig 4 presents a summary of the overall procedure for the fouruseful tools proposed in this study the Problem Table Algorithmwith multiple utility targets the Total Site Problem Table Algorithm(TS-PTA) the Total Site Utility Distribution (TSUD) table and theTotal Site Sensitivity Table (TSST)

6 Conclusions

In the following we present a summary of the contributions of this work

1) A new method was developed for calculating multiple utilitylevels in the PTA that is simpler than that presented by Costa

and Queiroz [17] This work introduced the use of multipleutility cascades to determine multiple utility levels for indi-vidual PTAs and TS-PTAs This tool enables the multiple utilitytargeting for individual processes to be done effectively usingthe numerical approach which produces more accurate results

2) The TS-PTA was introduced for TSHI We further demonstratedthat the TS-PTA yields more accurate results for TSHI analysiswhen compared with a graphical approach which is prone toinaccuracies The tool saves time and effort in determiningamounts of heat interchange among plants compared withgraphically constructed CCs GCCs TSPs and SCCs This toolcould be explored further for the variable supply and demandTotal Site problem as proposed by Varbanov and Klemes [9]Also TS-PTA could be used for continuous and batch processes

that may not be conveniently solved using graphical tools

3) The Total Site Utility Distribution (TSUD) table can be bene1047297cialfor the design of a Total Site utility distribution network Thistool can be used to visualise and design the heat transfernetwork in the system between utility streams and processstreams

4) The Total Site Sensitivity Table (TSST) is introduced to analyseTotal Site sensitivity A typical example is TSST can be use foranalysing the variation in a plantrsquos utility requirements whenone of the integrated site plants is shutdown for reasons suchas scheduled maintenance (eg for repairing faulty parts orclearing unwanted material in the reactor) periodic shutdowns(eg summer district heating shutdowns in the northernhemisphere) operability problems or unpredicted accidentsTSST results can also be used for utility design and productionplanning

The present research can be extended for the optimisation of cogeneration potential A prior study on assisted heat transfer [11]can also be integrated into the TS-PTA These developments shouldbe especially useful in increasing the applicability of the TS-PTAHeat storage in Total Site system also could be explored throughthe mathematical tool proposed

Acknowledgements

The authors would like to thank the Universiti TeknologiMalaysia for providing 1047297nancial support through the UTM Inter-national Education Experience Fund and the 1047297nancial support fromthe Hungarian project TAacuteMOP-422B-101-2010-0025 and to theUniversity of Pannonia in Hungary for supporting the collaboration

Nomenclature

Ts Initial Supply Temperature (C)

Tt Final Target Temperature (C)T0 Shifted Temperature (C)T00 Double-shifted Temperature (C)CC Composite CurveGCC Grand Composite CurveCW Cooling WaterHP High-Pressure SteamHW Hot WaterLIES Locally Integrated Energy SectorLPS Low-Pressure SteammCp Heat Capacity Flowrate (kWC)PTA Problem Table AlgorithmQcmin Minimum Cooling Requirement (kW)Qhmin Minimum Heating Requirement (kW)

SCC Site Composite CurveSGCC Site Grand Composite CurveSSSP Site SinkeSource Pro1047297leTS Total SiteTSP Total Site Pro1047297leTSHI Total Site Heat IntegrationTSST Total Site Sensitivity TableTSUD Total Site Utility DistributionTS-PTA Total Site Problem Table AlgorithmUTA Uni1047297ed Targeting AlgorithmDH Stream Heat Load (kW)DTminpp Minimum Temperature Difference Between Process

Stream (C)DTminup Minimum Temperature Difference Between Utility And

Process Streams (

C)




References

[1] VR Dhole B Linnhoff Total site targets for fuel co-generation emission andcooling Comput Chem Eng 17 (1993) S101eS109

[2] K Raissi Total site integration PhD Thesis UMIST Manchester UK 1994[3] J Klemes VR Dhole K Raissi SJ Perry L Puigjaner Targeting and design

methodology for reduction of fuel power and CO 2 on total site Appl ThermEng 7 (1997) 993e1003

[4] S Ahmad DCW Hui Heat recovery between areas of integrity ComputChem Eng 15 (12) (1991) 809e832

[5] F Mareacutechal B Kalitventzeff Energy integration of industrial sites toolsmethodology and application Appl Therm Eng 18 (1998) 921e933

[6] K Matsuda S Tanaka M Endou T Iiyoshi et al Energy saving study ona large steel plant by total site based pinch technology Appl Therm Eng(2012) doi101016japplthermaleng201111043

[7] PS Varbanov S Doyle R Smith Modelling and optimization of utiltiysystems Chem Eng Res Des 82 (A5) (2004) 561e578

[8] S Perry J Klemes I Bulatov Integrating waste and renewable energy toreduce the carbon footprint of locally integrated energy sectors Energy 33(2008) 1489e1497

[9] PS Varbanov JJ Klemes Total site integrating renewables with extendedheat transfer and recovery Heat Transfer Eng 31 (9) (2010) 733e741

[10] PS Varbanov JJ Klemes Integration and management of renewables intototal slice with variable supply and demand Comput Chem Eng 35 (9)(2011) 1815e1826

[11] S Bandyopadhyay J Varghese V Bansal Targeting for cogeneration potentialthrough total site integration Appl Therm Eng 30 (2010) 6e14

[12] A Kapil I Bulatov R Smith JK Kim Site-wide low-grade heat recovery witha new cogeneration targeting method Chem Eng Res Des (2012)doi101016jcherd201109001

[13] A Ghannadzadeh S Perry R Smith Cogeneration targeting for site utilitysystems ApplTherm Eng (2012) doi101016japplthermaleng201110006

[14] Z Fodor P Varbanov J Klemes Total site targeting accounting for individualprocess heat transfer characteristics Chem Eng Trans 21 (2010) 49e54

[15] PS Varbanov Z Fodor JJ Klemes Total site targeting with process speci1047297cDTmin Energy (2012) doi101016jenergy201112025

[16] B Linnhoff JR Flower Synthesis of heat exchanger networks AIChE J 24

(1978) 2 parts Part I systematic generation of energy optimal network 633-642 Part II evolutionary generation of networks with various criteria of optimality 642-654

[17] ALH Costa EM Queiroz An extension of the problem table algorithm formultiple utilities targeting Energ Convers Manage 50 (2009) 1124e1128

[18] UV Shenoy Uni1047297ed targeting algorithm for diverse process integrationproblems of resource conservation networks Chem Eng Res Des 89 (12)(2011) 2686e2705

[19] R Smith Chemical Process Design and Integration John Wiley amp SonsChichester UK 2005

[20] I Kemp Pinch analysis and process integration in B LinnhoffDW Townsend D Boland GF Hewitt BEA Thomas AR Guy RH Marsland(Eds) A User Guide on Process Integration for Ef 1047297cient Use of Energy seconded IChemE Rugby UK 1994 Elsevier Amsterdam The Netherlands 2007

[21] J Klemes F Friedler I Bulatov P Varbanov Sustainable in Process IndustryIntegration and Optimization McGraw Hill New York US 2010

[22] Canmet ENERGY Pinch Analysis For the Ef 1047297cient Use of Energy Water andHydrogen Natural Resource Canada Varennes 2003































individual plant








Table 1




Table 2




B5 Cold 50 250 0400 20 55 255

Table 3









individual plant













Table 4a


1 2 3 4 5 6 7

Trsquo ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Heat

Cascade

Single

Utility

Heat

Cascade20 40 70 15

230 0 2250

40 -15 -600

190 -600 1650

50 5 250

140 -350 1900

10 45 450

130 100 2350

40 -25 -1000

90 -900 1350

30 -45 -1350

60 -2250 0

10 40 400

50 -1850 400





Table 4b


1 2 3 4 5 6 7

T ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Cascade

Single

Utility

Cascade3 15 23 4 2

255 0 100

20 -2 -40

235 -40 60

30 -05 -15

205 -55 45

10 -45 -45

195 -100 0

81 215 17415

114 16415 17415

19 -15 -285

95 1613 1713

40 -3 -120

55 1493 1593

10 -1 -10

45 1483 1583

10 -4 -40

35 1443 1543















Table 5a


1 2 3 4 5 6 7 8 9

Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

Heat

Cascade

Utility

Consumed

Generated

(kW)

Heat Sink

Source20 40 70 15

270 0 HPS 600

40 0 0

230 230 0

40 -15 -600 600

190 190 0

1007 5 5035

17993 5035 MPS 0

3993 5 19965

140 140 250

641 45 28845

13359 53845 LPS 1650

359 45 16155

130 130 700

40 -25 -1000 300

90 90 0

30 -45 -1350 1350

6060 0

Pinch

60 0

10 40 400-400

50 50 0

35 0 0

15 0 CW 400




Table 6


1 2 3 4 5 6 7 8 9


Net heatsink (kW)


Initial heatcascade




0 113719 0HPS 270 0 700 700 700

700 43719 0MPS 17993 21650 0 21650 0

48350 65369 21650LPS 13359 99631 1650 65369 43719

113719 0 (Pinch) 0CW 15e20 73019 0 73019 L73019

407 73019 0

Table 5b


Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

HeatCascade

Utility

Consumed

Generated(kW)

Heat Sink

Source3 15 23 4 2

270 0 HPS 100

10 0 0 0

255 260 0

20 -2 -40 40

235 240 0

30 -05 -15 15

205 210 0

10 -45 -45 45

195

200 0Pinch

190 0

1007 215 21651 -21650

17993 0 MPS 21650

4634 215 99631 -99631

13359 0 LPS 99631

2459 215 52869 -33019

114 109 -1985

19 -15 -285 0

95 90 -170

40 -3 -120 0

55 50 -50

10 -1 -10 0

45 40 -40

10 -4 -40 0

35 30 0

15 0 0 0

15 0 CW 33019





heat de1047297










Table 7

















Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References





























individual plant













Table 4a


1 2 3 4 5 6 7

Trsquo ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Heat

Cascade

Single

Utility

Heat

Cascade20 40 70 15

230 0 2250

40 -15 -600

190 -600 1650

50 5 250

140 -350 1900

10 45 450

130 100 2350

40 -25 -1000

90 -900 1350

30 -45 -1350

60 -2250 0

10 40 400

50 -1850 400





Table 4b


1 2 3 4 5 6 7

T ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Cascade

Single

Utility

Cascade3 15 23 4 2

255 0 100

20 -2 -40

235 -40 60

30 -05 -15

205 -55 45

10 -45 -45

195 -100 0

81 215 17415

114 16415 17415

19 -15 -285

95 1613 1713

40 -3 -120

55 1493 1593

10 -1 -10

45 1483 1583

10 -4 -40

35 1443 1543















Table 5a


1 2 3 4 5 6 7 8 9

Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

Heat

Cascade

Utility

Consumed

Generated

(kW)

Heat Sink

Source20 40 70 15

270 0 HPS 600

40 0 0

230 230 0

40 -15 -600 600

190 190 0

1007 5 5035

17993 5035 MPS 0

3993 5 19965

140 140 250

641 45 28845

13359 53845 LPS 1650

359 45 16155

130 130 700

40 -25 -1000 300

90 90 0

30 -45 -1350 1350

6060 0

Pinch

60 0

10 40 400-400

50 50 0

35 0 0

15 0 CW 400




Table 6


1 2 3 4 5 6 7 8 9


Net heatsink (kW)


Initial heatcascade




0 113719 0HPS 270 0 700 700 700

700 43719 0MPS 17993 21650 0 21650 0

48350 65369 21650LPS 13359 99631 1650 65369 43719

113719 0 (Pinch) 0CW 15e20 73019 0 73019 L73019

407 73019 0

Table 5b


Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

HeatCascade

Utility

Consumed

Generated(kW)

Heat Sink

Source3 15 23 4 2

270 0 HPS 100

10 0 0 0

255 260 0

20 -2 -40 40

235 240 0

30 -05 -15 15

205 210 0

10 -45 -45 45

195

200 0Pinch

190 0

1007 215 21651 -21650

17993 0 MPS 21650

4634 215 99631 -99631

13359 0 LPS 99631

2459 215 52869 -33019

114 109 -1985

19 -15 -285 0

95 90 -170

40 -3 -120 0

55 50 -50

10 -1 -10 0

45 40 -40

10 -4 -40 0

35 30 0

15 0 0 0

15 0 CW 33019





heat de1047297










Table 7

















Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References




























Table 4b


1 2 3 4 5 6 7

T ( C)( C)

mCp (kW C)

(kW C) (kW)

Initial

Cascade

Single

Utility

Cascade3 15 23 4 2

255 0 100

20 -2 -40

235 -40 60

30 -05 -15

205 -55 45

10 -45 -45

195 -100 0

81 215 17415

114 16415 17415

19 -15 -285

95 1613 1713

40 -3 -120

55 1493 1593

10 -1 -10

45 1483 1583

10 -4 -40

35 1443 1543















Table 5a


1 2 3 4 5 6 7 8 9

Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

Heat

Cascade

Utility

Consumed

Generated

(kW)

Heat Sink

Source20 40 70 15

270 0 HPS 600

40 0 0

230 230 0

40 -15 -600 600

190 190 0

1007 5 5035

17993 5035 MPS 0

3993 5 19965

140 140 250

641 45 28845

13359 53845 LPS 1650

359 45 16155

130 130 700

40 -25 -1000 300

90 90 0

30 -45 -1350 1350

6060 0

Pinch

60 0

10 40 400-400

50 50 0

35 0 0

15 0 CW 400




Table 6


1 2 3 4 5 6 7 8 9


Net heatsink (kW)


Initial heatcascade




0 113719 0HPS 270 0 700 700 700

700 43719 0MPS 17993 21650 0 21650 0

48350 65369 21650LPS 13359 99631 1650 65369 43719

113719 0 (Pinch) 0CW 15e20 73019 0 73019 L73019

407 73019 0

Table 5b


Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

HeatCascade

Utility

Consumed

Generated(kW)

Heat Sink

Source3 15 23 4 2

270 0 HPS 100

10 0 0 0

255 260 0

20 -2 -40 40

235 240 0

30 -05 -15 15

205 210 0

10 -45 -45 45

195

200 0Pinch

190 0

1007 215 21651 -21650

17993 0 MPS 21650

4634 215 99631 -99631

13359 0 LPS 99631

2459 215 52869 -33019

114 109 -1985

19 -15 -285 0

95 90 -170

40 -3 -120 0

55 50 -50

10 -1 -10 0

45 40 -40

10 -4 -40 0

35 30 0

15 0 0 0

15 0 CW 33019





heat de1047297










Table 7

















Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References





































Table 5a


1 2 3 4 5 6 7 8 9

Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

Heat

Cascade

Utility

Consumed

Generated

(kW)

Heat Sink

Source20 40 70 15

270 0 HPS 600

40 0 0

230 230 0

40 -15 -600 600

190 190 0

1007 5 5035

17993 5035 MPS 0

3993 5 19965

140 140 250

641 45 28845

13359 53845 LPS 1650

359 45 16155

130 130 700

40 -25 -1000 300

90 90 0

30 -45 -1350 1350

6060 0

Pinch

60 0

10 40 400-400

50 50 0

35 0 0

15 0 CW 400




Table 6


1 2 3 4 5 6 7 8 9


Net heatsink (kW)


Initial heatcascade




0 113719 0HPS 270 0 700 700 700

700 43719 0MPS 17993 21650 0 21650 0

48350 65369 21650LPS 13359 99631 1650 65369 43719

113719 0 (Pinch) 0CW 15e20 73019 0 73019 L73019

407 73019 0

Table 5b


Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

HeatCascade

Utility

Consumed

Generated(kW)

Heat Sink

Source3 15 23 4 2

270 0 HPS 100

10 0 0 0

255 260 0

20 -2 -40 40

235 240 0

30 -05 -15 15

205 210 0

10 -45 -45 45

195

200 0Pinch

190 0

1007 215 21651 -21650

17993 0 MPS 21650

4634 215 99631 -99631

13359 0 LPS 99631

2459 215 52869 -33019

114 109 -1985

19 -15 -285 0

95 90 -170

40 -3 -120 0

55 50 -50

10 -1 -10 0

45 40 -40

10 -4 -40 0

35 30 0

15 0 0 0

15 0 CW 33019





heat de1047297










Table 7

















Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References



























Table 6


1 2 3 4 5 6 7 8 9


Net heatsink (kW)


Initial heatcascade




0 113719 0HPS 270 0 700 700 700

700 43719 0MPS 17993 21650 0 21650 0

48350 65369 21650LPS 13359 99631 1650 65369 43719

113719 0 (Pinch) 0CW 15e20 73019 0 73019 L73019

407 73019 0

Table 5b


Trsquo

( C)

Trsquorsquo

( C) ( C)

mCp (kW C)

(kW C) (kW)

Multiple

Utility

HeatCascade

Utility

Consumed

Generated(kW)

Heat Sink

Source3 15 23 4 2

270 0 HPS 100

10 0 0 0

255 260 0

20 -2 -40 40

235 240 0

30 -05 -15 15

205 210 0

10 -45 -45 45

195

200 0Pinch

190 0

1007 215 21651 -21650

17993 0 MPS 21650

4634 215 99631 -99631

13359 0 LPS 99631

2459 215 52869 -33019

114 109 -1985

19 -15 -285 0

95 90 -170

40 -3 -120 0

55 50 -50

10 -1 -10 0

45 40 -40

10 -4 -40 0

35 30 0

15 0 0 0

15 0 CW 33019





heat de1047297










Table 7

















Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References




























heat de1047297










Table 7

















Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References







































Table 8




Table 9




Table 10






D1 Cold 15 60 6000 1333333 20 65D2 Cold 15 80 5000 769232 20 85

Table 12




Table 13



Net heatsink (kW)


Initial heatcascade

Final heatcascade



0 1193790 0HP 170 304 304 304

304 1193486 0ST 125 296717 776931 480214 480214

480518 648470 0HW 50e60 149571 760692 611122 611122

1091640 0 0CW 10 3515 3515 L22727

1088125 3515 0




Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References



























Table 14



Normaloperation

Plant Ashutdown


Plant Bshutdown


Plant Cshutdown


Plant Dshutdown


HP 304 304 0 304 0 0 304 304 0

ST 480214 776931 296717 81077 399137 466519 13695 116115 364099

PinchHW 611122 682132 71008 689682 75860 586317 24806 124765 486357









with ∆Tminup


with ∆Tminup























(TSUD) Table







(TSST)



















6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References




































6 Conclusions









Acknowledgements


Nomenclature





Process Streams (

C)




References



























References

























liew, 2012 - numerical technique for total site sensitivity analysis.pdf

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