Petrocontrol

FCCU Advanced Control atChevron Pembroke Refinery

ERTC8th to 10th May 2006

Yen Koo CVXZak Friedman Petrocontrol

Steve Park AMT

Petrocontrol

FCC at Pembroke Refinery

• Initial Hydro skim refinery commissioned in 1967

• Cracking facilities commissioned in 1983 (Texaco side by side Rx/Rg unit, with a main fractionator and gas concentration section)

• Can process over 35% resid of total throughput of over 100,000 BPSD (600m3/hr - One of the Biggest FCC in Europe)

• Feed mix variation is in the region of 0.908 to 0.92 SG

• Last major turn around is during 2003

Petrocontrol

History of APC at Pembroke

• Pembroke Refinery has a long history of APC since 1987

• First MVC controller on FCC – 1988 (DMC) – with separate controller for Rx/Rg, and Mainfrac

• 2001, RMPCT replaced DMC, retained original structure, and added deeth, debut, napsplit

• Very limited success at each time (mainfrac didn’t work, lack of co-ordination between applications, tray damage)

• First Principle Inferentials first used in early 1990’s and have been deployed across most refinery units

Petrocontrol

FCCU APC Reengineering

• Potentially US$ 4millions/yr yet to be captured (carried a study on FCC APC during 2004) - Need to completely revamp FCC APC

• Scope of the revamp to cover reactor, regenerator, mainfrac, deeth, debut

• Main focus of the application and this paper is the Fractionator section due to major difficulties in managing this section of the unit

• Major feed limiting constraints are mainly in the Fractionator section

• RMPCT is the control technology used

• New FCCU application commissioned in July 2005

Petrocontrol

True Economic optimum

Hydraulic Const.

Rx/Rg

Temperature

WGC & others

Column fouling/

flooding limitation System Pressure

Product

Purity

Operating within Constraints

Operator's

Preferred

Operating

Region

MVC

Operating

Region

Eg. Rx bed Temp.Rg flu gas Temp.Excess O2,Cyclone Vel

Eg. Rx/Rg DP.Mainfrac top PSCSV/RCSV – DPAnd OPMainfrac OVHD P

Eg. Control valve Saturation OP – reflux& cooling system

LCGO draw TY DP, Level,Glitsch grid flow, TPA DP, ICGO wash downMainfrac bottom Temp.

HCN90 & EPHHCN90 & EPLCGO FlashSlurry DensityC2 spec in Ole

Max Tot. feed, Max Resid, ROTMax prod: LCGO (up-grade more HCGO) Max HHCN (match ULSG Capacity)Max Ole (match Alky Capacity) Min usage Air, Min C3 loss to offgas

WGC Anti-surgeAirblower anti-surgeHP steam limitation

Petrocontrol

FCCU application overview

• Applications are as follows:– Rx_Rg/mainFrac/Deeth (better integration and optimisation) –

55CVs,22MVs,11DVs– Single application to cover Debutaniser (8CVs,4MVs,6DVs)

• Large scope application with sub controllers deployed for ease of maintenance and operator intervention. (Sub controller switch AM/CL code

supplied by AMT)

• Customised Operator displays developed by CVX and AMT– Easy monitoring and operated upon (by panel operators)– Accommodation for switching access

• First principle Inferential model based on GCC (Petrocontrol)

Petrocontrol

Overview of Revamp Design

Eg. Rx/Rg DP.Mainfrac top PSCSV/RCSV – DPAnd OPMainfrac OVHD P

Eg. Rx bed TRg flu gas T.Excess O2,Cyclone Vel

LCGO draw DP & LevelGlitsch grid flow, TPA DP, ICGO wash downMF BTM T.cooling duty

HHCN90 & EP

LCGO Flash

C2 spec in Ole

HCN90 & EP

HCGO Density

WGC Anti-surgeHP STM limitation

Airbloweranti-surge

C5 in Ole prod.

Reboil capacity from LCGO PA / Reflux

ICGO PA / RefluxHCGO PA / Reflux

CoolingCapaciy

Down stream units limitation

Typical Constraints

Typical prod. & spec.

RMPCT Application

Petrocontrol

Schematic of Main fractionator

E-1

P-2

Reactor Effluent

Slurry Product

606060

P-6

P-7LCG O Product

I-2

P-9

P-10

P-11

ICG O PA

Bottom PA

LCG O PA

E-3

P-12

P-13

HHCN Product

P-14

E-7Cold FeedE-11

TPA

E-14

E-15

E-16

Lean O il to

Absorber

W et G as

M in Tray W ash M in G rid Flow

M ax btm tem p M ax velocities

M ax yield on resid feed

M ax to m in trayw ash

Flash point spec

90% Dist

90% Dist

M ax lvl 93%

Flood lim it

Tem p m in “dew point”

Petrocontrol

Project details Schedule and contract

• Project was completed in a 8 month window.

• Inferential model provided by Petrocontrol, and implemented and subsequent re-calibrated by CVX (VBA-model for easy maintaining and calibration)

• APC model jointly developed and implemented by CVX and AMT (one engineer each)

• Operator training package jointly developed by CVX and AMT (computer based self-learning, interactive)

• Project completed under budget with benefits higher than expected

Petrocontrol

FCCU APC Application Success Factors

• New FCCU application commissioned in mid-June 2005

• High operator acceptance

• Good average controller uptime (>95% when process available)

• Fractionator control now much improved, this is a key issue for the FCCU unit operations.

• Payback achieved within a month

Petrocontrol

Feature – inferentials/Specs Control

• Fractionator:

– LCGO Flash Point

– HHCN ASTM 90% & End point

– HCN ASTM 90% & End point

• Gas Plant

– Deeth bottom % C2 slippage

– Olefin % C5

– LCN RVP• Note: no analyser or lab updates used for biasing inferences

Petrocontrol

Highlight - Inferential models

CVX VBA model

Based on GCC

AM/CL model

Petrocontrol

Sample Model – Spec Control

MF Top-T MF OVHD-T LCGO prod. HCGO PA LCGO RBL Deeth RBL Ambient-T

HCNpt90

HCN EP

HHCN90pt

HHCNEP

LCGOFP

DeethBottom

C2

Petrocontrol

Highlight - LCGO Flash Point control

LCGO Flash Point Control

0

20

40

60

80

100

120

12/12/04 12/01/05 12/02/05 12/03/05 12/04/05 12/05/05 12/06/05 12/07/05 12/08/05 12/09/05 12/10/05 12/11/05 12/12/05 12/01/06 12/02/06

0

1

2

3

4

5

6

7

8

9

10

Infer LCGO FP

Lab LCGO FP

Infer LCGO FP Sdev

Iinferential recalibrated &

new controller

commissioned

Average Standard deviation is reduced by 1DegC

Petrocontrol

150

155

160

165

170

175

180

185

190

195

200

12/12/04 12/01/05 12/02/05 12/03/05 12/04/05 12/05/05 12/06/05 12/07/05 12/08/05 12/09/05 12/10/05 12/11/05 12/12/05 12/01/06 12/02/06

0

1

2

3

4

5

6

7

8

9

10

HCN90_Lab

02MFN90.PV

HCN90_Lab.stdev

Average Standard deviation is reduced by 1DegC

HCN90 spec control

Controller Commissioned

Highlight – HCN90 spec control

Petrocontrol

Feature – mainfrac control

• Optimise where possible the Fract bottoms heat removal Control Fractionator bottom temperature

• Prevent Fractionator flooding

• Maximise heat removal and balance duty around the column

• Ensure column packed sections are kept wet

• Ensure Slurry oil density remain on control within tight limits

• Minimise fouling probabilities in Slurry system

• Sustains Debutaniser on control even though reboiler (HCGO) exchanger fouling occurs

Petrocontrol

Sample Model – Main Frac control

Feed ROT MF Top-T LCGO prod. HCGO PA ICGO PA HHCN prod

MainFracBottom Temp.

PackedSection

ICGOWash

LCGODrawLVL

LCGODrawDP

HCGOVisc

HCGODensity

Petrocontrol

Highlight - LCGO Section dP Sensitivity to Flood

LCGO Section dP

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

12/12/04 12/02/05 12/04/05 12/06/05 12/08/05 12/10/05 12/12/05 12/02/06

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

LCGO Section dP

Std Dev

Flood point

Unit being pushed and

stability retained

Controller

commissioned

Petrocontrol

Highlight - LCGO Draw Tray Level

LCGO Draw Self Regulating Level

50

60

70

80

90

100

12/12/04 12/02/05 12/04/05 12/06/05 12/08/05 12/10/05 12/12/05 12/02/06

0

2

4

6

8

10

12

14

16

18

20

Draw tray level

Level stdevTray Full, LCGO section

flooded

Project KO and Pretest

and dynamic test

Phase

Controller Commissioned

Unit being pushed

Petrocontrol

Highlight - Fractionator BTM T Critical Unit limitation

Fractionator bottom temperature

280

290

300

310

320

330

340

350

360

370

380

12/12/04 12/02/05 12/04/05 12/06/05 12/08/05 12/10/05 12/12/05 12/02/06

0

2

4

6

8

10

12

14

16

18

20

Bottom Temp

Stdev

355°C is High Operating Limit

Controller

Commissioned

Petrocontrol

Feature – Optimisation direction

• Maximise Total Feed (match scheduling)• Max Resid processing to Regen limitations• Minimise load on Blower and expander• Stay in safe system delta P range (slide valves)

– max cat circulation• Maximise Conversion• Run to minimum Regen excess O2 (>1%)• Max LCGO draw against MIN internal reflux

• Significant operator issue

• Minimises the Deethaniser C3’s loss to offgassubject to C2 content at bottom (ole prod)

Petrocontrol

Sample Model – Rx/Rg optimisation

Tot-Feed Reactor-Temp Resid-Feed Rx/Rg-DP Feed-Preheat MF Top-P Air-blower

ExcessO2

Rx bedTemp

RCSVDP

RCSVOP

AirblowAnti-srg

WGCAnti-srg

Cat.Circ.

Petrocontrol

Unit Feed and Yields in M3/HR Shows increase in recovery of LCGO whilst sustaining bottom conditions

Feed with LCGO and ICGO Wash

0

100

200

300

400

500

600

700

12/12/04 12/02/05 12/04/05 12/06/05 12/08/05 12/10/05 12/12/05 12/02/06

Feed to unit

Tray wash

LCGO Product

Feed rate conditions dictated by refinery and plant

issues, Application ran at >95% from start of

application

Controller

commissioned

Increased recovery of LCGO at expence

of internal reflux (traywash) and hence

Slurry yield - Gain of 1

Petrocontrol

Highlight – Excess O2 optimisation

Excess O2 regen flu gas

0

1

2

3

4

5

6

12/12/04 12/01/05 12/02/0512/03/05 12/04/05 12/05/05 12/06/05 12/07/05 12/08/05 12/09/05 12/10/05 12/11/05 12/12/05 12/01/06 12/02/06

02AR2451.PV

02AR2451.PV.stdev

Controller

Commissioned

Unit is pushed to the limit

Petrocontrol

Highlight – Deeth Optimisation

0

5

10

15

20

25

30

35

14/09/2004 14/11/2004 14/01/2005 14/03/2005 14/05/2005 14/07/2005 14/09/2005 14/11/2005 14/01/2006

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

DEETH OFF GAS

C2 IN LPG

02DC2C2V.PV.stdev

Controller

Commissioned

Deeth Offgas minimisation

Petrocontrol

Feature – operator Acceptance

• Easy & user friendly APC monitoring display

• Comprehensive operator’s training

Petrocontrol

Highlight – Custimised Operator Display

Able to switch on/off, between Sub-controller

Able to drop any CVs or MVs

Able to change Low/High Limit

Able to switch on/off the whole

controller

Able to see which are the critical

variables

Petrocontrol

Highlight – sample training slide

Overview – How to navigate through the Training

R x /R g : C V 1 5 – 0 2 R X C Y V V .P V – R e g e n e ra to r C yc lo n e O u tle t V e lo c ity

C 1 9

A tm o s p h e r icR e s id

H o t F e e d

C o ld F e e d

2 1 F C

2 7 55

F e e dS u rg eD ru mLC

0 1 2

E 2 01E 2 08

E 20 2

P C

7 3 8

T C

0 2 8

F e e dP re -

H e a te r

R e a c to r

R e g e n e r a to r

F Y

2 59

F I

25 2S tea m

P D R

2 0 1

P D R

2 0 2

F C

2 2 0

F C

2 21

S te a m

S te a m

T C

2 1 5

L C

2 2 4

Z I

2 2 2

P I

2 1 7

P I

2 1 6

P D I

2 1 8

S P

2 1 8

C on de n sa te

T C

2 5 0

A R

2 4 5 1

E x c e ss

O 2

T R

74 8

T R

7 6 1

D e ns e

B e d

N ew

C at

O ff - G a s

M a inF ra c

E 2 09

S te am

S te am

A ir

O il

A ir

B l ow e rE xp a nd er M og e n

M 1

M 2

M 3

M 4

M 6

M 7

M 8

M 9

C 1

C 2

C 3

C 4

C 5

C 1 8

C 6

C 1 5

C 3 6

C 5 3

C 5 4

C 1 3C 1 2

Z I

2 6 7

C 1 6

C 1 7

F R

24 8

C 7

F ra c t io n a to r O v e rh ea d P A

L C G O P A H C G O P A

C 1 9

A tm o s p h e r icR e s id

H o t F e e d

C o ld F e e d

2 1 F C

2 7 55

F e e dS u rg eD ru mLC

0 1 2

E 2 01E 2 08

E 20 2

P C

7 3 8

T C

0 2 8

F e e dP re -

H e a te r

R e a c to r

R e g e n e r a to r

F Y

2 59

F I

25 2S tea m

P D R

2 0 1

P D R

2 0 2

F C

2 2 0

F C

2 21

S te a m

S te a m

T C

2 1 5

L C

2 2 4

Z I

2 2 2

P I

2 1 7

P I

2 1 6

P D I

2 1 8

S P

2 1 8

C on de n sa te

T C

2 5 0

A R

2 4 5 1

E x c e ss

O 2

T R

74 8

T R

7 6 1

D e ns e

B e d

N ew

C at

O ff - G a s

M a inF ra c

E 2 09

S te am

S te am

A ir

O il

A ir

B l ow e rE xp a nd er M og e n

M 1

M 2

M 3

M 4

M 6

M 7

M 8

M 9

C 1

C 2

C 3

C 4

C 5

C 1 8

C 6

C 1 5

C 3 6

C 5 3

C 5 4

C 1 3C 1 2

Z I

2 6 7

C 1 6

C 1 7

F R

24 8

C 7

F ra c t io n a to r O v e rh ea d P A

L C G O P A H C G O P A

C 1 9

A tm o s p h e r icR e s id

H o t F e e d

C o ld F e e d

2 1 F C

2 7 55

F e e dS u rg eD ru mLC

0 1 2

E 2 01E 2 08

E 20 2

P C

7 3 8

T C

0 2 8

F e e dP re -

H e a te r

R e a c to r

R e g e n e r a to r

F Y

2 59

F I

25 2S tea m

P D R

2 0 1

P D R

2 0 2

F C

2 2 0

F C

2 21

S te a m

S te a m

T C

2 1 5

L C

2 2 4

Z I

2 2 2

P I

2 1 7

P I

2 1 6

P D I

2 1 8

S P

2 1 8

C on de n sa te

T C

2 5 0

A R

2 4 5 1

E x c e ss

O 2

T R

74 8

T R

7 6 1

D e ns e

B e d

N ew

C at

O ff - G a s

M a inF ra c

E 2 09

S te am

S te am

A ir

O il

A ir

B l ow e rE xp a nd er M og e n

M 1

M 2

M 3

M 4

M 6

M 7

M 8

M 9

C 1

C 2

C 3

C 4

C 5

C 1 8

C 6

C 1 5

C 3 6

C 5 3

C 5 4

C 1 3C 1 2

Z I

2 6 7

C 1 6

C 1 7

F R

24 8

C 7

F ra c t io n a to r O v e rh ea d P A

L C G O P A H C G O P A

N o o p tim is a tio n is s e t fo r th is C V .

T h is C V c a n b e d ro p p e d o u t w it h R M P C T s t il l r u n n in g .

T h e reg e n e ra to r c y c lo n e v e lo c it y is k e p t w ith in th e ra n g e o f 1 5 m /m in to 3 0 m /m in to p ro v id e a g o o d s e p a ra t io n w i th o u t c a u s in g a n e x c e s s iv e p re s s u re d ro p . T h is is g e n e ra lly c o n tro lle d b y th e a ir b lo w e r .

M V 5 – 0 2 P C 0 3 0 .S PM a in F ra c t io n a to r T op P re s s u re S e t P o in t

M

D e -e th a n is e r O p e ra to r S c re e n

T h is is a s c re e n s h o t o f th e F C C U A d v a n c e d C o n tr o l S u b -M e n u fo r th e D e -e th a n is e r s u b -c o n tro lle r .

C lic k o n th e ta g -n a m e to d is p la y th e p ro c e s s s c h e m a t ic s h o w in g its in te ra c tio n w ith o th e r v a r ia b le s .

M

RMPCT Move Strategy (MV vs CV) : FCCU - Rx/Rg/MF/DeE (De-Eth Section)How to read the

Chart, Example=>

FC410OP is High, RMPCT will move 1st PDC064 Up and FC069 Down, 2nd TC400R Down

FC410OP is Low , RMPCT will move 1st PDC064 Down and FC069 Up, 2nd TC400R Up

CV

MV

02F

C017

02T

C215

02T

C028

21F

C2755

02P

C030

02S

P218

02F

Y259D

02F

C220

02F

C221

02T

C1967

02T

C075

02F

C2612

02F

C2368

02F

C2369

02F

C1926

02F

C044

02F

C067

02F

C2175

02P

DC

064

02F

C069

02T

C400R

High 0 U 0 D 1 D

Low 0 D 0 U 1 U

High 0 D 1 ULow 0 U 1 D

High 0 D 0 D 1 D

Low 0 U 0 U 1 U

High 1 D

Low 1 U

High 1 DLow 1 U

High 1 U

Low 1 D

02FR399

02DC2VLV

02DC2C2V

02FC410OP

02PDC064OP

02FC069OP

FCCU De-Eth RMPCT Move Strategy (MV vs CV)

Rx/Rg

MFra

DeEth

DeBut

NapSp

•Number (0, 1, 2, etc.) refers to the order of MV’smovement, with 0 as the most likely to be moved, and becoming less likely as the number increases•Direction of MV’s movement is defined by

U as to increase (or move up)D as to decrease (or move down)

•High/Low are the CV’s operating boundaries when is breached, will cause MVs to move in the defined order and direction.•Click on the tag-name to display the process schematic showing its interaction with other variables

M

MM Navigating buttonsSlide title, eg. CV, MV etc.

Control

hint on this CV or MV

Click on any Dark grey box

To view detail of the linked CV or MV info

CV or MV being

discussed on this

schematic

This box are linked CVs

or MVs on other slide

Click on it to view detail

MV vs CV:Blue move

in same

direction

Red moves in opposite

direction

Navigating buttonsSlide title, eg. CV, MV etc.

Control

hint on this CV or MV

Click on any Dark grey box

To view detail of the linked CV or MV info

CV or MV being

discussed on this

schematic

This box are linked CVs

or MVs on other slide

Click on it to view detail

MV vs CV:Blue move

in same

direction

Red moves in opposite

direction

Click on those buttons to

see DCS Ops RMPCT display for each section

Click on any of the MV or CV tags to

view detail schematic

Click on those buttons to

see DCS Ops RMPCT display for each section

Click on any of the MV or CV tags to

view detail schematic

Click on those buttons to see RMPCT Move

Strategy for each section

Click on any of

the MV or CV tags to view detail

schematic

Click on those buttons to see RMPCT Move

Strategy for each section

Click on any of

the MV or CV tags to view detail

schematic

Help Instructions (click on Help Instructions (click on ““herehere”” boxes to see more): boxes to see more): Each CV and MV is explained via a set of 3 standard slides :1. DCS Ops display,click to see live DCS screen shot. Normally Ops

performs actions such as turn on/off RMPCT, change Hi/Lo limit of CV or MV, drop off CV or MV on this display. Click here to see more.

2. Process Schematic, click here to see FCC process flow diagram with CV and MV labels. Click here to see more

3. RMPCT Move Strategy Matrix: click here to see typical MV’s move when at CV constraint. Click here to see more.

At top right corner of every slide, there are 6 navigating buttons here to aid user to navigating through out this presentation.

On every slide, click xxx to show / hide more control information for the CV or MV in discussion, click xxx to see the related DCS Ops Display, click xxx to view the related RMPCT Move Strategy Matrix, click xxx to return to the CV or MV in discussion, click xxx to advance to next slide. If not how to navigate through, click xxx to view this HELP slide

At any time to exit from the training, press the EscEsc key on the keyboardReady to start…..then click here to begin the tutorial

Help Instructions (click on Help Instructions (click on ““herehere”” boxes to see more): boxes to see more):

Each CV and MV is presented by a set of 3 standard slides :1. DCS Ops display,click to see live DCS screen shot. Normally Ops

performs actions such as turn on/off RMPCT, change Hi/Lo limit of CV or MV, drop off CV or MV on this display. Click here to see more.

2. Process Schematic, click here to see FCC process flow diagram with CV and MV labels. Click here to see more

3. RMPCT Move Strategy Matrix: click here to see typical MV’s move when at CV constraint. Click here to see more.

At top right corner of every slide, there are 6 navigating buttons here to aid user to navigating through out this presentation.

On every slide, click xxx to show / hide more control information for the CV or MV in discussion, click xxx to see the related DCS Ops Display, click xxx to view the related RMPCT Move Strategy Matrix, click xxx to return to the CV or MV in discussion, click xxx to advance to next slide. If not how to navigate through, click xxx to view this HELP slide

At any time to exit from the training, press the EscEsc key on the keyboardReady to start…..then click here to begin the tutorial

Here-3

Here-5

Here-1

Here-7

M

Here-2

Here-4

Here-6

Click on it to view next

slide

Click on it to view previous

slide

M

Click on it to

view DCS Ops display

Click on it to

view DCS Ops display

Click on it to view RMPCT

Move Strategy

Click on it to view RMPCT

Move Strategy

Click on it to view this HELP slide

Click on it to view control

hints

Click on it to view control

hints

Here-8

Petrocontrol

Thank you

Questions