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Control and operation of dividing-wall columns with vapor split - - PowerPoint PPT Presentation

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1 Control and operation of dividing-wall columns with vapor split manipulation PhD Defense Presentation Deeptanshu Dwivedi Jan 18 th , 2013 Trondheim Dwivedi, D., PhD Defense Presentation January 18th, 2013 2 Outline Introduction

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SLIDE 1

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 1

Control and operation of dividing-wall columns with vapor split manipulation

PhD Defense Presentation

Deeptanshu Dwivedi

Jan 18th, 2013 Trondheim

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SLIDE 2

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 2

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 3

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 3

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 4

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 4

Introduction & Scope

  • Conventional distillation is energy intensive process.
  • Dividing-wall columns for multicomponent separation:

– Petlyuk Arrangement for 3 & 4 product separation – Kaibel Arrangement for 4-product separation

  • Potential Energy Savings up to ~30 % in

– Kaibel Arrangement – Petlyuk Arrangements

  • Proven technology, >100 industrial applications
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SLIDE 5

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 5

Introduction & Scope..

Conventional direct sequence

ABCD A/B A BCD

B/C

B CD

C/D

D C A ABCD C/D ABC D

B/C

AB C

A/B

B

Conventional Indirect sequence

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SLIDE 6

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 6

Introduction & Scope..

  • Petlyuk arrangement for three-product separation

Up to 30 % energy savings compared to conventional arrangements Capital savings due to fewer reboilers and condensers

A/B B/C

ABC AB C A

A/C

BC B ABC A C B

A/C AB BC

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SLIDE 7

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 7

Introduction & Scope..

  • Kaibel arrangement for four-product separation

ABCD AB CD D A B C

A/B B/C B/C C/D

ABCD AB CD D A B C

A/B B/C B/C C/D

D ABCD CD A B C AB

B/C

D ABCD CD A B C AB

B/C

Upto 30% energy savings compared to conventional arrangements

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SLIDE 8

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 8

Introduction & Scope..

  • Petlyuk arrangement for four-product separation

Upto 50% energy savings compared to conventional arrangements

A/B B/C C/D

ABCD ABC BCD B D S1 S2

A/C B/D A/D

AB CD BC ABCD D B S1 S2 ABC BCD AB CD BC

A/B B/C C/D

ABCD ABC BCD B D S1 S2

A/C B/D A/D

AB CD BC ABCD D B S1 S2 ABC BCD AB CD BC

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SLIDE 9

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 9

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 10

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 10

Control Structures for 3-product Petlyuk*

  • Degrees of freedom: five
  • The control problem:

Feed ABC D C22 C21 S B C1 L VB RV = V1/VB V1 L1 RL = L1/L D1 B1

minimize . . in 0.5% in 0.5% in 0.5% in 0.5%

B

J V S T impurity top product light key side product heavy key side product impurity bottom product     

  • Constraints above: “optimally active”
  • However, the four compositions may not be

specified independently, due to presence of “holes”

  • r infeasible states*

* Dwivedi et al (2012), **Wolff & Skogestad (1995)

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SLIDE 11

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 11

Control Structures for 3-product Petlyuk..

  • the four product compositions

may not be specified independently, therefore: – Option I: Control xA

S+xC S

– Option II: Over-purify one of the products

  • To satisfy option I & II,

three DOFs are consumed: D, S & B

  • Two unconstrained DOF: RL &

RV – We propose, two self

  • ptimizing variables,
  • xA

B1

  • xC

D1

Feed ABC D C22 C21 S B C1 L VB RV = V1/VB V1 L1 RL = L1/L D1 B1

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SLIDE 12

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 12

Control Structures for 3-product Petlyuk..

Setpoint for CVs Over-purify:

  • the prefractionator products (xA

B1,

xC

D1) to introduce “back-off”

  • the main product, where there is

excess energy

Feed ABC D C22 C21 S B C1 L VB RV = V1/VB V1 L1 RL = L1/L D1 B1

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SLIDE 13

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 13

Control Structures for 3-product Petlyuk..

  • CS1 (RV available):

– control the sum of the impurities in S (xS

A + xS C)

Feed ABC B D C22 C1 C21

CC CC CC xC xA xB xA+xC xB

S

CC CC

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SLIDE 14

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 14

Control Structures for 3-product Petlyuk..

  • Closed loop simulations from CS1

Feed +20 % Feed -20 %

Feed rate changes may be handled well with CS1

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SLIDE 15

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 15

Control Structures for 3-product Petlyuk..

  • Closed loop simulations from CS1

– Poor dynamic response for some feed compositions using CS1 zF = [13.3 53.3 33.3] Side product flow is a poor MV, as it shows opposite gain for the two keys zF = [33.3 53.3 13.3]

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SLIDE 16

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 16

Control Structures for 3-product Petlyuk..

  • CS2 (RV available):

– overpurify one of the products – Use max selector with boil up

Feed ABC B D C22 C1 C21

CC CC CC xC xA xB xC xB

S

CC

>

xA CC CC

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SLIDE 17

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 17

Control Structures for 3-product Petlyuk..

  • Closed loop simulations from CS2

zF = [13.3 53.3 33.3] Good performance for feed composition disturbances (and feed rate) zF = [33.3 53.3 13.3]

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SLIDE 18

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 18

Control Structures for 3-product Petlyuk..

  • CS3 (RV NOT available)*:

– Light key in side product and light key in prefractionator bottoms remains uncontrolled – Recommended when B/C is the difficult split

*Ling and Luyben [2009], Kiss and Rewagad [2011]

Feed ABC B D C22 C1 C21

CC CC xC xB xC xB

S

CC CC

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SLIDE 19

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 19

Control Structures for 3-product Petlyuk..

  • Closed loop simulations from CS3

zF = [33.3 13.3 53.3] zF = [53.3 13.3 33.3] xA

S > 0.5% (Constraint)

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SLIDE 20

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 20

Control Structures for 3-product Petlyuk..

When A/B split becomes more difficult split, CS3 fails!!

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SLIDE 21

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 21

Control Structures for 3-product Petlyuk..

  • CS4 (RV NOT available):

– Use max selector with boil up – overpurify one/two of the products

Feed ABC B D C22 C1 C21

CC CC xC xA xB xC xB

S

CC xA

>

CC CC CC

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SLIDE 22

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 22

Control Structures for 3-product Petlyuk..

  • Closed loop simulations from CS4

zF = [33.3 13.3 53.3] zF = [53.3 13.3 33.3] Good performance for feed composition disturbances (and feed rate)

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SLIDE 23

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 23

Control Structures for 3-product Petlyuk..

Summary so far

  • Decentralized PI control structures with selector switch

can give good regulation for 3-Product Petlyuk Column

  • The over-purification cost little extra energy
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SLIDE 24

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 24

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 25

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 25

Operation of 4-product Kaibel column*

  • Height: 8 meters
  • Atmospheric pressure
  • Vacuum glass sections
  • 4 products
  • Packed Column with 6 mm Raschig

rings

  • Product & liquid split valves are

solenoid operated

  • Vapor split valves are motor driven
  • Labview interface

A B C D Feed (ABCD) A B C D Feed (ABCD) Feed (ABCD)

*Dwivedi et al (2012)

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SLIDE 26

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 26

Operation of 4-product Kaibel column..

  • 4-point decentralized temperature

control – one temperature in prefractionator – three temperatures in main column

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SLIDE 27

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 27

Operation of 4-product Kaibel column..

  • Cold Start-up

– Four temperatures are adjusted in closed loop to guide to desired steady state profile

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SLIDE 28

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 28

Operation of 4-product Kaibel column..

  • Steady state
  • peration using four-

point CS

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SLIDE 29

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 29

Operation of 4-product Kaibel column..

  • Set point changes

using four-point CS

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SLIDE 30

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 30

Operation of 4-product Kaibel column..

  • Disturbance: +20%

Feed Rate

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SLIDE 31

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 31

Operation of 4-product Kaibel column..

Experimental Data vs Model Experimental Data:

  • Temperature snapshots
  • Composition Snapshots
  • Manipulated variables: Power input, split ratios

Model (Assumptions):

  • Equilibrium Stage Model
  • VLE with Wilson model in liquid state, vapor ideal
  • Constant molar overflow
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SLIDE 32

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 32

Operation of 4-product Kaibel column..

Model Fitting procedure: Degree of freedom

  • 1. number of theoretical stages (fixed, using

HETP estimation)

  • 2. boilup (fixed, from experiments)
  • 3. feed composition (fixed, from experiments)
  • 4. liquid split ratio (fixed, from experiments)
  • 5. vapor split ratio (adjusted, using

experimental data)

  • 6. distillate product split ratio (adjusted, using

experimental data)

  • 7. upper side product split ratio (adjusted,

using experimental data)

  • 8. lower side product split ratio (adjusted,

using experimental data)

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SLIDE 33

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 33

Operation of 4-product Kaibel column..

Model Fitting Results

Temperatures Compositions Inputs

Very good agreement between the experimental steady-state data and the equilibrium stage model

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SLIDE 34

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 34

Operation of 4-product Kaibel column..

  • Experimental Results

vs Optimal Operation the experimental results were close to “optimal” operations

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SLIDE 35

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 35

Operation of 4-product Kaibel column..

Summary so far

  • stable operation of the four product Kaibel column can be achieved

with the 4-point temperature control scheme for start-up, steady state operation, as well as servo-regulatory performance

  • equilibrium stage model can be fitted to the experiments
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SLIDE 36

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 36

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 37

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 37

Active vapor split control*

Motivation boilup depends on Rv

  • energy saving potential can

be lost if the column is

  • perated away from the
  • ptimum vapor split ratio
  • Active vapor split may ensure

setting the optimum vapor split

*Dwivedi et al (2012)

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SLIDE 38

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 38

Active vapor split control..

the experimental setup

Two Vapor split valves

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SLIDE 39

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 39

Active vapor split control..

The vapor split valve

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SLIDE 40

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 40

Active vapor split control..

Vapor Split valve behavior

  • nly the first 10 steps of the 150 steps are really effective, the resolution is poor
  • the valve opening is too large
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SLIDE 41

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 41

Active vapor split control..

The initial total reflux experiment

V1 V2 Controller Output Valve Opening 1 0 % 100 % 0.5 (10 Steps) V1 V2 Controller Output Valve Opening 1 0 % 100 % 0.5 (10 Steps)

1 4 5 6 7 3 RL1 2

TS

V1 V2

T2 T5 TC RV

Q

∆T

1 4 5 6 7 3 RL1 2

TS

V1 V2

T2 T5 TC RV

Q

∆T

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SLIDE 42

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 42

Active vapor split control..

The initial total reflux experiment Vapor split control works well in closed loop for set point changes and disturbances

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SLIDE 43

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 43

Active vapor split control..

Active Vapor split control for four-product Kaibel column

  • 4-point decentralized temperature control

– one temperature in prefractionator by the vapor split valve – three temperatures in main column using product flows D, S1 & S2

1 4 5 6 7 3 RL1 2

T2S

V1 V2

T2 TC RV

F B

T3S T3 TC

D RL2 S1 RL3

T5S T5

S2

T7 TC T7S TC

RL4 Q 1 4 5 6 7 3 RL1 2

T2S

V1 V2

T2 TC RV

F B

T3S T3 TC

D RL2 S1 RL3

T5S T5

S2

T7 TC T7S TC

RL4 Q

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SLIDE 44

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 44

Active vapor split control..

Closed loop Results Vapor split control works well in closed loop for control of 4- product Kaibel column

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SLIDE 45

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 45

Active vapor split control..

Recommendations:

  • feedback control using vapor split valves to set “optimum vapor split”

– the vapor split valve is a very fast handle – no need to precisely measure the vapor split, the feedback action can “drive” the vapor split to its optimum value

  • the liquid split, is a precise input, can be used in “open loop/ manual

mode” for any economic objective

  • Use of two vapor valves with split range logic

– to get the full range of changes in vapor split – Minimum pressure drop

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SLIDE 46

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 46

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 47

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 47

Control Structures for 4-product Petlyuk Column*

  • Degrees of freedom: ten
  • The control problem:

J =cost of feed − value of products + cost of energy

C31 C32 C33

Feed

ABCD

B D S1 S2

C22 C1 C21

MV1 MV2 MV3 MV4 MV5 MV6 MV7 MV8 MV9 MV10

ABC BCD AB BC CD A B C D C31 C32 C33

Feed

ABCD

B D S1 S2

C22 C1 C21

MV1 MV2 MV3 MV4 MV5 MV6 MV7 MV8 MV9 MV10

ABC BCD AB BC CD A B C D *Dwivedi et al (2012)

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SLIDE 48

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 48

Control Structures for 4-product Petlyuk Column

Nominal inputs obtained from the Vmin diagram

Nominal boilup in subsections Nominal composition in subsections

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SLIDE 49

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 49

Control Structures for 4-product Petlyuk Column..

  • CS1

– Basic LV structure in each sub column – Boil up is used to control the key impurity in reboiler

C31 C32 C33 Feed ABCD B D S1 S2 C22 C1 C21

CC CC CC CC CC CC CC CC CC CC xD xA xC xA xD xB xB xC xD xC

C31 C32 C33 Feed ABCD B D S1 S2 C22 C1 C21

CC CC CC CC CC CC CC CC CC CC CC xD xA xC xA xD xB xB xC xD xC

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SLIDE 50

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 50

Control Structures for 4-product Petlyuk Column..

  • Closed loop simulations from CS1

Side impurity increases

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SLIDE 51

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 51

Control Structures for 4-product Petlyuk Column..

  • Why CS1 Failed?

C31 C32 C33 Feed ABCD B D S1 S2 C22 C1 C21

CC CC CC CC CC CC CC CC CC CC xD xA xC xA xD xB xB xC xD xC

C31 C32 C33 Feed ABCD B D S1 S2 C22 C1 C21

CC CC CC CC CC CC CC CC CC CC CC xD xA xC xA xD xB xB xC xD xC

CS1 failed when A/B is the more difficult split

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SLIDE 52

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 52

Control Structures for 4-product Petlyuk Column..

  • CS2

– Boilup controls the sum of light key in the products S1, S2 & B (i.e., xA

S1+xB S2+XC B)

C31 C32 C33 Feed ABCD B D S1 S2 C22 C1 C21

CC CC CC CC CC CC CC CC CC

∑

CC xD xA xC xA xD xB xB xC xD xA xB xC

C31 C32 C33 Feed ABCD B D S1 S2 C22 C1 C21

CC CC CC CC CC CC CC CC CC CC

∑

CC xD xA xC xA xD xB xB xC xD xA xB xC

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SLIDE 53

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 53

Control Structures for 4-product Petlyuk Column..

  • Closed loop simulations from CS2

Good performance for feed composition disturbances (and feed rate)

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SLIDE 54

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 54

Control Structures for 4-product Petlyuk Column..

  • CS3

– controlled variables are a sensitive stage temperature in each sub- column

C33 Feed ABCD B D S1 S2 C22 C21 C31 C32

TC

C1

TC TC TC TC TC TC TC TC TC

C33 Feed ABCD B D S1 S2 C22 C21 C31 C32

TC

C1

TC TC TC TC TC TC TC TC TC

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SLIDE 55

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 55

Control Structures for 4-product Petlyuk Column..

  • Closed loop simulations from CS3

Side impurity increases

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SLIDE 56

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 56

Control Structures for 4-product Petlyuk Column..

  • CS4

– master composition controller sets set point for slave temperature loops – Boilup controls the sum of light key in the products S1, S2 & B (i.e., xA

S1+xB S2+XC B)

xD xA xC xA xD xB xB xC xD

C33 Feed ABCD B D S1 S2 C22 C21

TC

C31 C32

CC TC

C1

CC TC CC TC CC TC CC TC CC CC TC CC CC TC TC

CC xA xB xC

∑

xD xA xC xA xD xB xB xC xD

C33 Feed ABCD B D S1 S2 C22 C21

TC

C31 C32

CC TC

C1

CC TC CC TC CC TC CC TC CC TC CC TC CC TC CC CC TC CC CC TC TC

CC xA xB xC

∑

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SLIDE 57

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 57

Control Structures for 4-product Petlyuk Column..

  • Closed loop simulations from CS4

Good performance for feed composition disturbances (and feed rate)

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SLIDE 58

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 58

Outline

  • Introduction & Scope
  • Chapter 3: Control structure selection for three-product Petlyuk

(dividing-wall) column

  • Chapter 4: Steady state and dynamic operation of four-product

dividing-wall (Kaibel) columns

  • Chapter 5: Active vapor split control for dividing-wall columns
  • Chapter 6: Control structure selection for four-product Petlyuk column
  • Chapter 7: Conclusions and further work
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SLIDE 59

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 59

Conclusions

  • Three-Product Petlyuk Column

– Single loop decentralized control structure with selector switches may lead to good regulation

  • Four-product Kaibel column

– Experimental verification of 4-point temperature control structure for startup, steady-state and servo-regulatory operation – Fitted steady state experimental data with a simple equilibrium based model

  • Active Vapour split control

– Experimentally verified that vapor split valve shall work with feedback loop

  • Four-Product Petlyuk Column

– Single loop decentralized control structure with summation loop leads to good regulation

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SLIDE 60

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 60

References

  • Dwivedi D., Halvorsen I.J., Skogestad S., Control structure selection for three-product Petlyuk

(dividing-wall) column”, Accepted for publication in Chemical Engineering and Processing: Process Intensification (2012), doi: “10.1016/j.cep.2012.11.006”.

  • Wolff, E. A., Skogestad, S., 1995. Operation of integrated three-product (Petlyuk) distillation columns.

Industrial & Engineering Chemistry Research 34 (6), 2094–2103

  • Anton A. Kiss, Rohit R. Rewagada, Energy efficient control of a BTX dividing-wall column, Computers

and Chemical Engineering 35 (2011) 2896– 2904

  • Hao Ling, William L. Luyben, Temperature Control of the BTX Divided-Wall Column, Ind. Eng. Chem.

Res., Vol. 49, No. 1, 2010

  • Dwivedi D., Standberg J., Halvorsen I.J., Skogestad S., Steady state and dynamic operation of four-

product dividing-wall (Kaibel) columns: Experimental Verification”, Accepted for publications in Industrial & Engineering Chemistry Research (2012), doi: “10.1021/ie301432z”.

  • Dwivedi D., Standberg J., Halvorsen I.J., Preisig, H.A., Skogestad S., Active vapor split control for

dividing-wall columns”, Accepted for publication in Industrial & Engineering Chemistry Research (2012), doi: “10.1021/ie3014346”

  • Dwivedi D., Halvorsen I.J., Skogestad S., “Control structure selection for four-product Petlyuk column”,

Accepted for publications in Chemical Engineering and Processing: Process Intensification (2012), doi: “10.1016/j.cep.2012.07.013”.

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SLIDE 61

January 18th, 2013 Dwivedi, D., PhD Defense Presentation 61

Further Works

  • In Chapter 3 & 6

– Alternate control structures may be explored – Soft sensor approach, instead of direct composition measurements – Design of column vs controllability may be studied – Multivariable control structures may be explored

  • In Chapter 4 & 5

– Different vapor split valves may be tried – Use set up for studying also three product Petlyuk column – Larger number of stages may be put in