Design Method for Heat ExchangerNetworks

2006

DISEÑO DE LA RED DEINTERCAMBIO

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2006

ROAD MAP

PROJECTS

SYNTHESIS

ANALYSIS

Project Selectionfor Implementation DETAILDESIGNENVIRONMENT

PROCE

SS SIMULATION ENVIRONMENTData Extraction

Network Design

ProcessImprovement Road Map

GenerateEvaluateSelect Options

THREE DAYCOURSE

I know what is thepotential for energyrecovery in my process.But, how should I designa process that achievesthe energy target ?

Energy Rec

Process Mod

¿Cómo consigo losobjetivos de mínimo

consumo de energía?

2©2000 AspenTech. All Rights Reserved.

ROAD MAP

PROJECTS

SYNTHESIS

ANALYSIS

Project Selectionfor Implementation DETAILDESIGNENVIRONMENT

PROCE

SS SIMULATION ENVIRONMENTData Extraction

Network Design

ProcessImprovement Road Map

GenerateEvaluateSelect Options

THREE DAYCOURSE

I know what is thepotential for energyrecovery in my process.But, how should I designa process that achievesthe energy target ?

Energy Rec

Process Mod

Our Example Problem

REACTOR

FEEDSTEAM

STEAMRECYCLE

PRODUCT

DistillationColumn

DISTVAP

CW

REAC.OUT

880

19801220

1620

2640

160°

160°

130°

220°

220°

210°

210° 270°

149°

178°

50°

60°160°

180°

= EXCHANGER DUTY, kW

TEMPERATURE, Cº

Tmin = 20°Q = 1000, Q = 800H Cmin min

Para nuestro ejemplo:

3©2000 AspenTech. All Rights Reserved.

REACTOR

FEEDSTEAM

STEAMRECYCLE

PRODUCT

DistillationColumn

DISTVAP

CW

REAC.OUT

880

19801220

1620

2640

160°

160°

130°

220°

220°

210°

210° 270°

149°

178°

50°

60°160°

180°

= EXCHANGER DUTY, kW

TEMPERATURE, Cº

Tmin = 20°Q = 1000, Q = 800H Cmin min

Let’s design the network

210° 160° 160° 50°

220° 180° 180° 60°

210° 160°

270° 180° 180° 160°

Product

Reac. Out

Feed

Recycle

Where should we start?

Diseñemos la red

4©2000 AspenTech. All Rights Reserved.

210° 160° 160° 50°

220° 180° 180° 60°

210° 160°

270° 180° 180° 160°

Product

Reac. Out

Feed

Recycle

Where should we start?¿Por dónde comenzar?

Divide the problemat the Pinch

Start at the Pinchand move away

This will ensure no Cross Pinch heat transfer

T T

H H

Pinch Pinch

PINCH BelowAbove

Identifique elpunto de corte

Comience en el punto de cortey luego muévase hacia afuera

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Divide the problemat the Pinch

Start at the Pinchand move away

This will ensure no Cross Pinch heat transfer

T T

H H

Pinch Pinch

PINCH BelowAbove

How should we match streams at the Pinch? T T

HH

Pinch Pinch

Hot Stream

ColdStre

amCold Stream

Hot Stream

BelowC CPPcold hot

AboveC CPPhot cold

C CP

(The CP Rule)

PIN OUT

¿Cómo definir los intercambios entrecorrientes en el punto de corte?

6©2000 AspenTech. All Rights Reserved.

T T

HH

Pinch Pinch

Hot Stream

ColdStre

amCold Stream

Hot Stream

BelowC CPPcold hot

AboveC CPPhot cold

C CP

(The CP Rule)

PIN OUT

Abajo Arriba

Which Streams should we match first?

Below Above

} Tmin Tmin {

Cold Utility

Hot Utility

1. Match with a stream INPossible if

CP CPIN OUT

2. Match with a streamaway from the Pinch

Possible

3. Match with utility

Possible

Finding partners for streams OUT ofthe Pinch is easy

Let’s examine streams OUT¿Qué corrientes se deben intercambiar primero?

Examinemos las corrientes de salidaAbajo Arriba

1. Match con una corriente de entradaPosible si

2. Match con una corrientelejos del punto de corte

7©2000 AspenTech. All Rights Reserved.

Below Above

} Tmin Tmin {

Cold Utility

Hot Utility

1. Match with a stream INPossible if

CP CPIN OUT

2. Match with a streamaway from the Pinch

Possible

3. Match with utility

Possible

Finding partners for streams OUT ofthe Pinch is easy

Let’s examine streams OUT

2. Match con una corrientelejos del punto de corte

Posible

3. Match con servicios auxiliares

Posible

Encontrar los intercambios para las corrientesque salen del punto de corte es sencillo

Below Above

} Tmin Tmin {

Cold Utility

Hot Utility

1. Match with a stream OUTPossible if

CP CPIN OUT

2. Match with a Streamaway from the Pinch

Not Possible( T violation)

3. Match with utilityNot Possible(Cross-Pinch)

Let’s examine streams IN

Finding partners for streams goingIN the Pinch is more difficult

Veamos las corrientes deentrada

1. Match con una corriente de salidaPosible si

2. Match con una corrientelejos del punto de corte

8©2000 AspenTech. All Rights Reserved.

Below Above

} Tmin Tmin {

Cold Utility

Hot Utility

1. Match with a stream OUTPossible if

CP CPIN OUT

2. Match with a Streamaway from the Pinch

Not Possible( T violation)

3. Match with utilityNot Possible(Cross-Pinch)

Let’s examine streams IN

Finding partners for streams goingIN the Pinch is more difficult

2. Match con una corrientelejos del punto de corte

No Posible

3. Match con servicios auxiliaresNo Posible

Encontrar los intercambios para las corrientesque entran al punto de corte es máscomplicado

How big should we make each match?

HH = 20

H = 100H

100

120

Try to maximize load to minimize number of matches(The “Tick Off” heuristic)

¿Qué cantidad de calor se debe intercambiaren cada match?

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HH = 20

H = 100H

100

120

Try to maximize load to minimize number of matches(The “Tick Off” heuristic)

Lo máximo posible!!!!!

H CP

210° 160°

220° 180°

210° 160°177.6°

270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

PRODUCT is the biggest stream INApply the CP Rule and Tick Off heuristic

880

Reac. Out

Above the Pinch

Apliquemos el procedimiento de diseño ennuestro ejemplo

Arriba PC

10©2000 AspenTech. All Rights Reserved.

H CP

210° 160°

220° 180°

210° 160°177.6°

270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

PRODUCT is the biggest stream INApply the CP Rule and Tick Off heuristic

880

Reac. Out

Above the Pinch

PRODUCTO es la mayor corrienteentrante

H CP

210° 160°

220° 180°

210° 160°177.6°

235.6°270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

REAC. OUT is the next biggest stream INAgain apply the CP Rule and Tick Off heuristic

880

1000Reac. Out

11©2000 AspenTech. All Rights Reserved.

H CP

210° 160°

220° 180°

210° 160°177.6°

235.6°270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

REAC. OUT is the next biggest stream INAgain apply the CP Rule and Tick Off heuristic

880

1000Reac. Out

REACTOR OUT es la siguientecorriente entrante

H CP

210° 160°

220° 180°

210° 160°177.6°

235.6°270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

Now place the matches away from the PinchFollow Tick Off heuristic

880

1000

190°

620Reac. Out

12©2000 AspenTech. All Rights Reserved.

H CP

210° 160°

220° 180°

210° 160°177.6°

235.6°270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

Now place the matches away from the PinchFollow Tick Off heuristic

880

1000

190°

620Reac. Out

Ahora ubique los matches lejosdel punto de corte

H CP

210° 160°

220° 180°

210° 160°177.6°

235.6°270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

Last place the heaters

880

1000

1000

190°

620

H

Reac. Out

13©2000 AspenTech. All Rights Reserved.

H CP

210° 160°

220° 180°

210° 160°177.6°

235.6°270° 180°

Product

Feed

Recycle

880 22

1620 18

1000 20

2500 50

Last place the heaters

880

1000

1000

190°

620

H

Reac. Out

Al último ubique los servicios auxiliares

160° 50°

180° 60°

180° 160°

Product

Feed

H CP

2640 22

360 18

2200 20

FEED is the only stream INApply the CP rule and Tick Off heuristic

Next, below the Pinch

220080°

Reac. Out

Ahora, debajo del punto de corte

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160° 50°

180° 60°

180° 160°

Product

Feed

H CP

2640 22

360 18

2200 20

FEED is the only stream INApply the CP rule and Tick Off heuristic

Next, below the Pinch

220080°

Reac. Out

FEED es la única corrienteentrante

160° 50°

180° 60°

180° 160°

Product

Feed

H CP

2640 22

360 18

2200 20

There are no more streams INNow we can place the coolers

440

360C

C

80°2200

Reac. Out

15©2000 AspenTech. All Rights Reserved.

160° 50°

180° 60°

180° 160°

Product

Feed

H CP

2640 22

360 18

2200 20

There are no more streams INNow we can place the coolers

440

360C

C

80°2200

Reac. Out

No hay más corrientes de entrada,ahora podemos ubicar los refrigeradores

Linking Above and Below together

210° 160° 50°

220° 180° 60°80°

210° 190° 177.6°

235.6°

160°

270° 180° 160°

Product

Feed

RecycleH

C

C

880

440

360

22001000

6201000

Q = 1000Hmin Q = 800Cmin

Design is on Target

Reac. Out

Uniendo las dos partes...

16©2000 AspenTech. All Rights Reserved.

210° 160° 50°

220° 180° 60°80°

210° 190° 177.6°

235.6°

160°

270° 180° 160°

Product

Feed

RecycleH

C

C

880

440

360

22001000

6201000

Q = 1000Hmin Q = 800Cmin

Design is on Target

Reac. Out

Se consiguen la metas dediseño!!!!

Sometimes, there are problems …..

HOT2

HOT1

COLD1

COLD2

COLD3

CP8

4

5

1

3

?

Missing a stream OUT

A veces, se presentan problemas...

17©2000 AspenTech. All Rights Reserved.

HOT2

HOT1

COLD1

COLD2

COLD3

CP8

4

5

1

3

?

Missing a stream OUTFalta una corriente de

salida!!!!

Let’s look at the problem more generally

HOT2

HOT3

HOT1

COLD1

COLD2

COLD3

?

?

For feasibilityN NIN OUT

T>90°

T >100°

100°

100°

100°

100°

100°

90°

90° 90°

90°

90°

CurrentlyN > NIN OUT

CurrentlyN > NIN OUT

AboveNo Cold Utility

BelowNo Hot Utility

Miremos un problema más general

18©2000 AspenTech. All Rights Reserved.

HOT2

HOT3

HOT1

COLD1

COLD2

COLD3

?

?

For feasibilityN NIN OUT

T>90°

T >100°

100°

100°

100°

100°

100°

90°

90° 90°

90°

90°

CurrentlyN > NIN OUT

CurrentlyN > NIN OUT

AboveNo Cold Utility

BelowNo Hot Utility

HOT2

HOT1

COLD1

COLD2

COLD3

CP8

4

5

1

3

Split a stream OUT of the Pinch

If N > NIN OUT

CP = 2

CP = 6

1

2

3

SI

19©2000 AspenTech. All Rights Reserved.

HOT2

HOT1

COLD1

COLD2

COLD3

CP8

4

5

1

3

Split a stream OUT of the Pinch

If N > NIN OUT

CP = 2

CP = 6

1

2

3

Divida una corriente de salidadel punto de corte

Another Example

HOT2

HOT1

COLD1

COLD2

COLD3

CP4

9

3

8

5

There are enough streams OUT butCP CP not possible for every Pinch MatchIN OUT

?

Otro ejemplo...

20©2000 AspenTech. All Rights Reserved.

HOT2

HOT1

COLD1

COLD2

COLD3

CP4

9

3

8

5

There are enough streams OUT butCP CP not possible for every Pinch MatchIN OUT

?

Hay suficientes corrientes de salida pero...no es posible para cada match

HOT2

HOT1

COLD1

COLD2

COLD3

CP4

9

3

8

5

We split a stream IN

What do we do ?

CP = 2

CP = 7

1

2

3

¿Qué debemos hacer?

21©2000 AspenTech. All Rights Reserved.

HOT2

HOT1

COLD1

COLD2

COLD3

CP4

9

3

8

5

We split a stream IN

What do we do ?

CP = 2

CP = 7

1

2

3

Dividimos una corriente entrante

However do not follow the rules blindly …..

HOT2

HOT2

HOT1

HOT1

COLD1

COLD1

COLD2

COLD2CP

CP

4

4

10

10

3

3

17

17

CP = 12

CP = 5

1

2

HOT2

HOT1

COLD1

COLD2

CP4

10

3

17

CP = 2

CP = 2

CP = 13

CP = 4

1

2

3

Splitting a stream INcauses the need tosplit a stream OUT

Splitting a streamOUT results in asimpler solution

Always try to minimize stream splits to reduce complexity

Another Example

Sin embargo, no debemos seguir las reglasciegamente...

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HOT2

HOT2

HOT1

HOT1

COLD1

COLD1

COLD2

COLD2CP

CP

4

4

10

10

3

3

17

17

CP = 12

CP = 5

1

2

HOT2

HOT1

COLD1

COLD2

CP4

10

3

17

CP = 2

CP = 2

CP = 13

CP = 4

1

2

3

Splitting a stream INcauses the need tosplit a stream OUT

Splitting a streamOUT results in asimpler solution

Always try to minimize stream splits to reduce complexity

Another Example

Siempre intentemos minimizar las bifurcaciones para reducirla complejidad

Resumen

Ubique el punto de corte y divida elproblema en dos partes

Realice losintercambiosen el punto decorte

Nin≤Nout

CPin≤CPout

Divida unacorriente de

salida

Divida unacorriente de

entrada

No

No

23©2000 AspenTech. All Rights Reserved.

Realice los intercambios remanentes

Ubique los serviciosauxiliares

Realice losintercambiosen el punto decorte

CPin≤CPout

Ubique la mayorcorriente de

entrada

CPin≤CPout

Maximice elintercambio

Divida unacorriente de

entrada

Paracada

match