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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
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
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