smart plant approach to increase plant...

Smart Plant Approach to Increase Plant Profitability

Donald J. Chmielewski

Department of Chemical & Biological Engineering

Illinois Institute of Technology

Miguel J. Bagajewicz

Department of Chemical Engineering

University of Oklahoma

2009 Annual Meeting of the

AIChE

Nashville, TN

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Traditional Plant Operation

Plant Measured Data

Servo-

Loops

MPC

RTO

State

Estimator

Parameter

Estimator

Estimation Units

Set-points

Set-points

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Smart Plant Operation

Plant Measured Data

Servo-

Loops

MPC

RTO

State

Estimator

Parameter

Estimator

Estimation Units

Set-points

Set-points

Smart Plant

Supervisor

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Smart Plant Topics

• Scheduling and Supervision (Enterprise Wide)

• Fault Detection and Diagnosis (Plant Wide)

• Safe Parking and Emergency Management (Plant

Wide)

• Process Efficiency and Sustainable Operation

(Plant Wide)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Motivating Example (Surge Tank)

q

q(sp)

FT

FC

qin

V

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Surge Tank Operating Scenario

q

q(sp)

FT

FC

qin

V

- Inlet flow (qin) is from a reactor and varies with time.

- Exit (q) to a separation unit which demands little variation.

- Tank should not over-flow or run dry.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Surge Tank Operating Scenario

q

q(sp)

FT

FC

qin

V

- Inlet flow: qin = 30 3 m3/min.

- Exit flow q = 30 1 m3/min.

- Tank volume V = 10 10 m3.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Open-Loop Operation

q

q(sp)

FT

FC

qin

V

- Inlet flow: qin = 30 3 m3/min.

- Exit flow q = 30 0 m3/min.

- Tank volume V = 10 10 m3.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Open-Loop Operation

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Open-Loop Operation (Disturbance Scenario b)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Open-Loop Operation

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

(disturbance a) (disturbance b)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Closed-loop Surge Tank

q(sp)

FT

FC

q

qin

V(sp)

LT

LC

V

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Closed-loop Level Control Surge Tank

+ -

qGp(s)Gc(s) +

+

qin Gd(s)

VV(sp)

ssGp /1)(

ssGd /1)(

s

KsGI

cc 11)(

2c

c

K

2I c

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Closed-loop Level Control Surge Tank

+ -

qGp(s)Gc(s) +

+

qin Gd(s)

VV(sp)

s

KsGI

cc 11)(

2c

c

K

2I c

Tuning Scenarios:

Case 1: c = 1 min.

Case 2: c = 10 min.

Case 3: c = 50 min.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Closed-Loop Operation (Case 1: c = 1 min )

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

Department of Chemical and Biological Engineering

Illinois Institute of Technology

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

Closed-Loop Operation (Case 1: c = 1 min )

(disturbance a) (disturbance b)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Closed-Loop Operation (Case 1: c = 10 min )

(disturbance a) (disturbance b)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Closed-Loop Operation (Case 1: c = 50 min )

(disturbance a) (disturbance b)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Extreme Cases

(Over Regulated) (Open-Loop)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Middle Ground

(Over Regulated) (Open-Loop)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

(c = 10 min )

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

The Operator’s Plight

Possible scenario

• Shift starts with the following operation (c = 10 min).

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

Department of Chemical and Biological Engineering

Illinois Institute of Technology

The Operator’s Plight

• But, then the disturbance changes to

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Vq

in

q

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

Department of Chemical and Biological Engineering

Illinois Institute of Technology

The Operator’s Plight

• Should the operator re-tune the controller?

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

(c = 10 min )

Department of Chemical and Biological Engineering

Illinois Institute of Technology

The Operator’s Plight

• Should the operator re-tune the controller?

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

(c = 10 min )

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

(c = 50 min )

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Plight Re-Examined

• Broader perspective on the process will yield solution.

q(sp)

FT

FC

q

qin

V(sp)

LT

LC

V

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Plight Re-Examined

• Broader perspective on the process will yield solution.

• Reconsider the separation unit downstream:

q(sp)

FT

FC

q

qin

V(sp)

LT

LC

V Separation

Unit

Nominal Throughput:

30 m3/min

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Plight Re-Examined

• Broader perspective on the process will yield solution.

• Reconsider the separation unit downstream:

q(sp)

FT

FC

q

qin

V(sp)

LT

LC

V Separation

Unit

Nominal Throughput:

30 m3/min

Maximum Throughput:

31 m3/min

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Plight Re-Examined

• Broader perspective on the process will yield solution.

• Reconsider the separation unit downstream:

q(sp)

FT

FC

q

qin

V(sp)

LT

LC

V Separation

Unit

Nominal Throughput:

30 m3/min

Maximum Throughput:

31 m3/min

Exit flow q = 30 1 m3/min.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Solution

0 10 20 30 40-5

0

5

10

15

20

25

30

35

time (minutes)

Ta

nk H

old

-up

(m

3)

or

Volu

metr

ic F

low

(m

3/m

in)

(c = 10 min ) • Reselect to the nominal

throughput.

• From 30 m3 / min

to 29 m3 / min

• Obtain guidance from

)( nom

design

nom

actual qqKP

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Plight

V

EDOR

* *

OSSOP

3129

20

0

Original

Operating Point

q

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Solution

V

EDOR

*

OSSOP

3129

20

0New BOP

q

*

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Solution

V

EDOR

* *

OSSOP

3129

20

0

Original

Operating Point

q

V

EDOR

*

OSSOP

3129

20

0New BOP

q

*

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Solution

V

EDOR

* *

OSSOP

3129

20

0

Original

Operating Point

q

V

EDOR

* *

OSSOP

3129

20

0

New BOP

q

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Model Predictive Control

LT

q(sp)

V(nom)

MPC

q(no

m)

V FT

FC

q

FTqin

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Operator’s Perspective

• Disturbance characteristics will impact the controller’s ability to meet operational criteria.

• In some cases, adjustment of the controller (re-tuning) will recover performance.

• In other cases, only recourse is modification of nominal operating conditions.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Impact on Smart Plant Operation

• Evolution of disturbance characteristics necessitates the ability to retune controllers.

• To enable such retuning, two technologies are needed:

1. A method to characterize disturbances.

2. A profit focused tuning method that is responsive to disturbance modeling.

Department of Chemical and Biological Engineering

Illinois Institute of Technology

Profit View of Smart Plant Operation

Plant Measured Data

Servo-

Loops

MPC

RTO

State

Estimator

Parameter

Estimator

Estimation Units

Set-points

Set-points

Disturbance

Characterization

Reselection of nominal

operating conditions

Retuning

of

controller