A Hybrid Simulation-Optimization Approach for the … · A Hybrid Simulation-optimization Approach For The Design Of ... •Side product stream (liquid or vapor) • (two phases)

© Juan A. Reyes-Labarta. AIChE meeting. October, 2012. Pittsburgh.

A HYBRID SIMULATION-OPTIMIZATION APPROACH FOR THE DESIGN OFINTERNALLY HEAT-INTEGRATED DISTILLATION COLUMNS

Juan A. Reyes-Labarta*, Jose A. Caballero, M.A. Navarro ([email protected])

© Juan A. Reyes-Labarta. AIChE meeting. October, 2012. Pittsburgh. 2

• Concepts and general configuration of HIDiC with single heat exchangers• Concepts and general configuration of HIDiC with single heat exchangers

• Motivation• Motivation

A Hybrid Simulation-Optimization Approach for the Design ofInternally Heat-integrated Distillation Column

A Hybrid Simulation-Optimization Approach for the Design ofInternally Heat-integrated Distillation Column

Outline

• Examples and conclusions• Examples and conclusions

• Future work (inclusion of LCA and environmental impact evaluation in the optimization problem)

• Future work (inclusion of LCA and environmental impact evaluation in the optimization problem)


A Hybrid Simulation-optimization Approach For The Design OfInternally Heat-integrated Distillation Column

A Hybrid Simulation-optimization Approach For The Design OfInternally Heat-integrated Distillation Column

- Increasing energy efficiency in chemical processes not only provides economic benefits but also reduces emissions resulting for process operations => more efficient and sustainable chemical processes

Environmental aspects (THERE IS NOT PLANET “B”)

Motivation (I)

- Distillation columns are one of the major energy consumers in chemical processes and therefore represent a key point in terms of energy efficiency

Feed

Distillate

Residue

LD

...

...

n=1

n=N

LD+DQD

QR

Motivations


Optimal design of generalized distillation columnsOptimal design of generalized distillation columns

n=i

Motivation (II): Simulation-Optimization approaches

Lk’,n+1

Vk’,n+1-(VGFk)

Vk’,n+2

(LGFk)

Lk,n(=Lk,NTk) (Lk+1,0)

k’= k (or k+1)

Hysys Flowsheet (tray by tray calculations)

Reyes-Labarta, Caballero & Marcilla. Computer Aided Chemical Engineering. 2012, 30: 1257-1261.

(multiple feeds, products and/or intermediate heat exchangers)


Schematic representations of the internal existing streams at the zone connecting consecutive sectors in the case of a generalized feed side stream (GFk).

5

Optimal location of all the side streams:

Optimal design of generalized distillation columns

•Intermediate Heat exchanger

•Side product stream (liquid or vapor)

• (two phases) Side feed stream

where zopt refers to the phase composition at the optimal change point of sector k. L and H are the indexes for light and heavy key components, respectively.

Marcilla, Reyes-Labarta & Serrano. “Review and extension of the McCabe-Thiele method covering multiple feeds, products and heat transfer stages” (2012). http://hdl.handle.net/10045/23195


Optimal design of absorption systems (MINLP)Optimal design of absorption systems (MINLP)

• Solution strategy: an logic-based Outer Approximation algorithm (NLP subproblems[Matlab-Aspen]-MILP master problem[Gams]).

Distillation Column(binary variables

associated with the existence of the trays)


Reyes-Labarta et al. Computer Aided Chemical Engineering. 2011, 29: 301-305.


Design of Internally Heat-Integrated Distillation Columns (HIDiC)

PossibleHeatIntegration!!

Feed

Distillate

Residue

LD

...

...

n=1

n=N

LD+DQD

QR

Conventional distillation column

Q B

(bottom)



Inter-Condenser and inter-reboiler benefits (McCabe-Thiele Method)

B

F 2

Q D

L 1, 0+ D

2

3

L 1, 0

Q

1 QE1

xB xDB,xB

D,xD

y

zF

s1

s2

s3

xB

F

QEyF

xF

xopt,F

D

yQE

yQE



Inter-Condenser and inter-reboiler benefits (McCabe-Thiele Method)

B

F 1

Q D

L 1, 0+ D

2

3

L 1, 0

Q

1

QA2

xQA zFxB xDB,xB

D,xD

y

s1

s2

s3

xB

F

QA

yF

xF

xopt,F

D



General representation of an internally heat-integrated distillation columnGeneral representation of an internally heat-integrated distillation column

B,xBB

F 2

Q D

D

L 1, 0+ D

3

4

L 1, 0

Q

2

QA3

1 Q E1

DD,xD

InternalHeat

Integration

(high pressure)

(low pressure)

Rectifying sector(light components)

Stripping sector(heavy components)



EV

cond

RSSS

Compp-H

Reb

F

IHER

D

QD

QR

Ln,RS

V1,SS

Ws

QIHT

-QIHT Ln,RS

(high pressure)

(low pressure)

General configuration of an internally heat-integrated distillation columnGeneral configuration of an internally heat-integrated distillation column

B

QB

Rectifying SectorStripping Sector



OBJECTIVE FUNCTIONSOBJECTIVE FUNCTIONS

opc CCTAC +=

1)1()1·(

)·(cos −++

+= n

n

compressorHXStcapitalannual iririr

CCC

∑=

+=hxsk

kHXS )cA·c(C 21

)](Wk3·log )k2·log(W [k1 S2

S10·8.5 ++=compressorC

lmkk

kk TU

QA

∆=

opDwSeRqop t)·Q·CW·CQ·C(C ++=

Capital recovery factor:ir = interest raten = life time of the equipment (years)

Cooling water

Electricity

Heat steam

© Juan A. Reyes-Labarta. AIChE meeting. October, 2012. Pittsburgh.13

We propose an approach that combines the advantages of commercial process simulator (Aspen‐Hysys) to converge distillation columns, with the advantages of using a metaheuristic algorithm (PSO: particle swarm optimization) which initially has the ability to escape from local optima and not require gradient information

The original particle swarm optimization algorithm (Kennedy & Eberhart, 1995)


SIMULATION-OPTIMIZATION APPROACHSIMULATION-OPTIMIZATION APPROACH


Systems studied:

- benzene + toluene

- propylene + propane

- methanol + water

- benzene + cyclohexane + toluene

- methanol + acetone + water

- methanol + ethyl-acetate + water

- propylene + i-butane + propane

- benzene + toluene + ethyl-benzene + styrene

NUMERICAL EXAMPLESNUMERICAL EXAMPLES


PSO algorithm



Condenser and reboiler duties, and compressor shaft work vs overall internal heat transferred (QIHT)

0 200 400 600 800 1000 1200 1400 1600 1800 20000

500

1000

1500

2000

2500

QIHT (kW)

Q (

kW)

QD

QR

WS

TRADEOFF: It is possible to optimize the TAC reducing also the environmental impacts by heat integration!!!

Slightly increase of the compressor

work

Internal heat transferred


Services (kW) and TAC with total number of trays Optimal solutions Example 1

0

500

1000

1500

2000

2500

3000

20 30 40 50 60 70 80

Total number of Trays

kW

0

100000

200000

300000

400000

500000

600000T

AC

Total Ext. ServicesQDQRWcompQIHTTAC

TAC

Total Ext. ServicesQIHT

QD

QRWcomp

16



Services (kW) and TAC evolution with Feed flow rateOptimal solutions Example 2

0

1000

2000

3000

4000

5000

80 100 120 140 160 180 200 220 240 260 280 300 320

Feed flow rate (kmol/h)

kW

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

TA

C


TAC

Total Ext. Services

QIHT

QD

QR

Wcomp

17



Services (kW) and TAC evolution with Feed flow rateOptimal solutions Example 3

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

80 100 120 140 160 180 200 220 240 260 280 300 320Feed flow rate (kmol/h)

kW

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

TA

C


TAC

Total Ext. Services

QIHT

QDQR

Wcomp

18



Services and TAC evolution with ∆P (Optimal solution)

0

500

1000

1500

2000

2500

3000

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3∆P(atm)

kW

0

50000

100000

150000

200000

250000

300000

350000

TA

C


TAC

Total Ext. Services

QIHT

QD

QRWcomp

19




General Conclusions (I)General Conclusions (I)

• The economic interest of HIDiC depends on the ratio between the cost of the electricity and the cost of the heating steam. However, environmentally friendly and more energy efficient technologies should be introduced to provide more sustainable processes that minimize the environmental impacts.

• HIDiC with a small number of intermediate heat exchangers can present interesting benefits, providing savings around 20-40% comparing with conventional distillation columns, depending on the components of the system, the flow rate and composition of the feed stream, and the product purities desired.

• The possibility of heat exchange between stages that are not at the same high in both sectors can also improve the efficiency of the configuration, together with the optimal location of the feed stream that is generally at the first stages of the stripping sector (but not always!!).

• The pressure difference between both sectors is also a key point of the process. The pressure of the rectifying sector should be high enough to allow the heat transfer between both sectors, but it should be as low as possible to minimize the compressor costs.



General Conclusions (II)General Conclusions (II)

• Traditional HIDiC (with heat transfer along the total length of each sector) are less efficient when we have flat temperature profiles inside the column (i.e. with small variation in the equilibrium composition of the different trays) and high products purity.

However, HIDiC with a small number of intermediate heat exchangers can improve the feasibility and efficiency of the configuration in this kind of separations.


Design of sustainable processes

General configuration of a classical vapour recompression distillation column (VRC)

General configuration of a classical vapour recompression distillation column (VRC)

EV

cond

Comp

Reb

F1

B

DQp-cond

Qp-H

QIHT

(high pressure)

(low pressure)

R=L1,0

WsF2

p-H

p-cond

Mainly for systems with small temperature difference between the top and bottom products


A>B>C

A

B

C

I

II

III

IV

V

VI

Petlyuk configuration

A>B>C

A

B

C

I

II

III

IV

V

VI

Divided Wall Column

…Thermodynamically equivalent to…

• Thermally coupled columns/sequences or its thermodynamically equivalent Divided Wall Column (DWC) configurations

• Thermally coupled columns/sequences or its thermodynamically equivalent Divided Wall Column (DWC) configurations

Energy efficiency: heat integration configurations

Caballero, Reyes-Labarta & Grossmann. Computer Aided Chemical Engineering. 2003, 14(C): 59-64 and 2004, 18(C): 361-366.

A

B

C

D

E

ABCDE

ABC

CDE

AB

BC

DE

CD

A

B

C

D

E

ABCDE

ABC

CDE

AB

BC

DE

CD

A

B

C

D

E

ABCDE

ABC

CDE

AB

BC

DE

CD



New Vapor Compression Alternatives in Thermally Coupled Distillation ColumnsNew Vapor Compression Alternatives in Thermally Coupled Distillation Columns

Caballero, Navarro & Reyes-Labarta. Paper 399b. AIChE Meeting 2012. https://aiche.confex.com/aiche/2012/webprogram/Paper267695.html


-Reyes-Labarta, J.A. “Diseño de Columnas de Rectificación Y Extracción Multicomponentes”. Biblioteca Virtual Miguel de Cervantes (Universidad de Alicante), 1998.

http://www.cervantesvirtual.com/FichaObra.html?Ref=4845&ext=pdf

http://hdl.handle.net/10045/10023

-A. Marcilla, A. Gómez, J.A. Reyes, M.M. Olaya.; New Method for Quaternary Systems Liquid-liquid Extraction Tray to Tray Design. Industrial & Engineering Chemistry Research, 38, 3083-3095 (1999). http://dx.doi.org/10.1021/ie9900723-A. Marcilla, A. Gómez, J.A. Reyes; New Methods for Designing Distillation Columns ofMulticomponent Mixtures. Latin American Applied Research and International Journal of ChemicalEngineering, 27, 51-60 (1997). http://hdl.handle.net/10045/24679-Reyes, J.A.; Gomez, A.; Marcilla, A. Graphical concepts to orient the minimum reflux ratio calculation on ternary mixtures distillation. Industrial & Engineering Chemistry Research39(10),3912-3919 (2000). http://dx.doi.org/10.1021/ie9907021-J.A. Reyes-Labarta, I.E. Grossmann; Disjunctive Programming Models for the Optimal Design Of Liquid-liquid Multistage Extractors and Separation Sequences. AIChE Journal. 2001, 47 (10), 2243-2252. http://dx.doi.org/10.1002/aic.690471011

- J.A. Reyes-Labarta y I.E. Grossmann. Optimal Synthesis of Liquid-liquid Multistage Extractors. Escape-11 (European Symposium of Computer Aided Process Engineering), Capec (Computer Aided Process Engineering Center). ISBN: 0-444-50709-4 (Dinamarca, 2001). http://dx.doi.org/10.1016/S1570-7946(01)80076-6

Bibliography


-Reyes-Labarta, J.A.; Caballero, J.A.; Marcilla, A. A Novel Hybrid Simulation-Optimization Approach for the Optimal Design of Multicomponent Distillation Columns. Computer Aided Chemical Engineering. 2012, 30, 1257-1261. http://dx.doi.org/10.1016/B978-0-444-59520-1.50110-X-Reyes-Labarta, J.A.; Brunet, R.; Caballero, J.A.; Boer, D.; Jiménez, L. Integrating process simulation and MINLP methods for the optimal design of absorption cooling systems. Computer Aided Chemical Engineering. 2011, 29, 301-305. http://dx.doi.org/10.1016/B978-0-444-53711-9.50061-4-Brunet, R.; Reyes-Labarta, J.A.; Guillén-Gosálbez, G.; Jiménez, L.; Boer, D. Combined Simulation-Optimization Methodology for the Design of Environmental Conscious Absorption Systems. Computers and Chemical Engineering, 2012, 46, 205-216http://hdl.handle.net/10045/24678-Marcilla et al. “Review and extension of the McCabe-Thiele method covering multiple feeds, products and heat transfer stages” (2012). http://hdl.handle.net/10045/23195

Bibliography

-Reyes-Labarta, J.A.; Navarro M.A.; Caballero, J.A. A Hybrid Simulation-OptimizationApproach for the Design of Internally Heat-Integrated Distillation Columns. Paper 488e. AIChE2012 Annual Meeting (Energy Efficiency by Process Intensification). https://aiche.confex.com/aiche/2012/webprogram/Paper267732.html-Caballero, Reyes-Labarta & Grossmann. Synthesis of Integrated Distillation Systems. Computer Aided Chemical Engineering. 2003, 14(C): 59-64.-Caballero, Reyes-Labarta & Grossmann. Simultaneous Design of Heat Integrated and Thermally Coupled Distillation Systems. Computer Aided Chemical Engineering. 2004, 18(C): 361-366.-Caballero, Navarro & Reyes-Labarta. New Vapor Compression Alternatives In Thermally Coupled Distillation. Paper 399b. AIChE Meeting 2012 (Advances in process intensification) https://aiche.confex.com/aiche/2012/webprogram/Paper267695.html

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A Hybrid Simulation-Optimization Approach for the … · A Hybrid Simulation-optimization Approach For The Design Of ... •Side product stream (liquid or vapor) • (two phases)