csi 2016: april 27-28, 2016 continuous digester ... · continuous digester optimization using...
TRANSCRIPT
© ABB
| Slide 1 May 2, 2016
CONTINUOUS DIGESTER OPTIMIZATION USING ADVANCED PROCESS CONTROL
CSI 2016: April 27-28, 2016
Abhijit Badwe
ABB Pulp & Paper Control Systems Tech. Centre, Singapore
© ABB
| Slide 2
Continuous Digester Advanced Control Outline
• Challenges in continuous cooking
• Conventional approaches to control
• Need for multivariable control
• Advanced control for continuous digesters: OPT800 Cook/C
• Case Study: Implementation of OPT800 Cook/C
© ABB
| Slide 3
Pulp Mill Operation Challenges in Continuous Cooking
• Variations in raw material
• Production rate changes
• Large transport delays
• Complex nonlinear dynamics at low Kappa numbers
• Infrequent Kappa measurements (every 15-20 min)
• Assumed blow consistency
• Chip level variation results in varying degrees of cooking
© ABB
| Slide 4 May 2, 2016
Digester Kappa (end-point) control Conventional approach
Challenges:
Large time delay
Infrequent blow line
Kappa measurement
Non-linear process
interactions
Chip-size, packing
density and raw
material variations
Seasonal variations
Supervisory control
© ABB
| Slide 5 May 2, 2016
Digester chip level control Conventional approach
Challenges
Blow flow as Primary
Manipulated Variable
Estimated blow
consistency
Varied Digester bottom
conditions
Variations in chip
retention time
Supervisory control
© ABB
| Slide 6
Continuous Digester Control Need for a multivariable control approach
• Kappa number affected by H Factor and Alkali/Wood ratio
• Chip level affected by multivariable effects from:
• Chip meter speed
• Blow flow
• Bottom dilution flow
• Scraper speed
• Conventional approaches are usually univariate.
© ABB
| Slide 7
Systematic method for solving
multivariable problems
Main ingredients
Process model
Constraints
Objective function
Model predicts system behaviour
some steps into the future
Solves optimization problem at
every sampling time
Model Predictive Control (MPC)
© ABB
| Slide 8 May 2, 2016
Digester mid-point Kappa Control Model Predictive Control
• ANN model for mid-point
Kappa (soft sensor)
• Pulp tracking module:
tracks key process
variables throughout
digester
• Blow line Kappa used for
output bias correction
• REA (residual alkali)
control to the target
Kappa MPC control
© ABB
| Slide 9 May 2, 2016
Digester chip level control Model Predictive Control
Model Predicative Control
Actively manipulate
scrapper speed
Blow consistency (soft
sensor)
Ensure stable fiber
discharge (blow flow
variations minimized)
Stabilize chip column
movement to provide
uniform cooking
conditions
CMM – constraint
Management Module
MPC for Level control
© ABB
| Slide 10
© ABB Group
May 2, 2016 | Slide 10
OPT800 Cook/C
Continuous Digester Advanced Process Control System
DCS
Continuous Cooking Process
Tracking
Function
Soft Sensor
Constraint
Management
Module
Model
Predictive
Controller
Operator
Displays
OPT800 Cook/C
Process Variables
Tracked Measurements
Soft Sensor Measurements
Operating Parameters
CV Targets
Optimized Setpoints
Dynamic
Constraints Model
Predictions
PVs
PVs
PVs PVs PVs
© ABB
| Slide 11
© ABB Group
May 2, 2016 | Slide 11
OPT800 Cook/C
System Architecture using 800xA APC platform
AC800M
Remote I/O Field
Devices
Engineering Station
Aspect
Servers
Process Portal Client
AC800 Connectivity
Servers
Operator HMI
• MPC faceplates
• MPC tuning
• Process graphics
800xA Run Time Components
• APC Afw service
• APC engines / algorithms
• MPC Control Applications
• Kappa
• Level
AC800M Run Time Components
• PPOptCook/C CoreLib
• PPOptCook/C TemplateLib
• Control connections to sensors and PID’s
800xA Model Builder (off-line)
• Off-line Engineering tool kit, for
Model Identification, Controller
Tuning, and Simulation
IMP Run time Engine
• Kappa Inferential measurement
800xA APC Interface Lib
© ABB
| Slide 12 May 2, 2016
Case study : Mondi Swiecie, Poland Digester Advanced Process Controls
Located in Northern Poland
Pulpmill with 2 Fiber lines, 4 Paper
Machines
Project scope
Replace measurex DCS system
OPT800 Cook/C for both lines
‒ Kappa MPC control
‒ Level MPC control
OPT800 Wash for both lines
‒ Conductivity controls at each
stage
‒ Dilution Factor control
APC improves digester operations in Mondi
© ABB
| Slide 13 May 2, 2016
Case study : Mondi Swiecie, Poland APC Methodology
• Control Loop Audit
• Analysis, Findings
• Action plan
Process Fingerprint
• Chip Bin
• Impregnation Vessel
• Digester Vessel
Pulp Tracking • Blow consistency
• Kappa model
• Install IMP
• Data collection
Soft Sensor Models
• Kappa MPC
• Dig level MPC
• Step Test
• Develop models
• Deploy MPC
MPC • Performance Test
• Case Study
• Success Story
Results Report
• Quarterly Audit
• Benchmarking results
• ServicePort
Performance Monitoring
Step 1:
Diagnose Step 3:
Sustain Step 2:
Implement
Service Service
Diagnose Implement Sustain
© ABB
| Slide 14 May 2, 2016
Case study : Mondi Swiecie, Poland Digester APC Overview
Operator overview
APC display
Faceplates
Switch APC and
Supervisory mode
© ABB
| Slide 15 May 2, 2016
Case study : Mondi Swiecie, Poland Mid-point Kappa control Results before & after APC implementation
Performance test run results Kappa variability reduced by 56.4%
Average Upper Lt Lower Lt Sigma % results
Before APC 88.86 89.00 85.00 3.68 36.8%
After APC 87.93 89.00 85.00 1.61 71.4%
Improvements 0.93 2.08 94%
Before APC % of data within Limits 36.8%
After APC % of Data within Limits 71.4%
Blow Kappa Test Run
56.4%
© ABB
| Slide 16 May 2, 2016
Case study : Mondi Swiecie, Poland Residual Alkali control Results before & after APC implementation
C12 Residual Alkali Variability reduced by 48%
0 .0 0
0 .2 5
0 .5 0
0 .7 5
1 .0 0
1 .2 5
T w o S ig m a C o m p a r i so nP o i n t s = 4 5 6 1
2
Sig
ma
1 2
C 1 2 R e A lk a l i_ B e fo r e A P C C 1 2 R e A lk a l i_ A fte r A P C
C 1 2 R e A lk a l i_ B e fo r e A P C 1 .3 2 7 7 0 4 2C 1 2 R e A lk a l i_ A fte r A P C 0 .6 4 7 9 4 3 3
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0 3 5 0 0 4 0 0 0 4 5 0 0
O v e r la y C o lu m n C o m p a r is o nC o lu m n s = 2 , P o in ts = 4 5 6 1
Re
s
Alk
ali
D a ta P o in ts
C 1 2 R e A lk a li_ B e fo r e A P C C 1 2 R e A lk a li_ A fte r A P C
48 %
© ABB
| Slide 17 May 2, 2016
Case study : Mondi Swiecie, Poland Digester chip-level control Results before & after APC implementation
Trend captured from customer historian while
commissioning OPT800 Cook/C for digester
Dig chip level - 5 days trend 40% reduction in 2-Sigma
APC ON APC OFF
0
5
1 0
1 5
2 0
2 5
T w o S i g m a C o m p a r i s o nPo i n t s = 4 5 6 1
Dig
C
hip
L
ev
el
1 2
D ig lv l_ B e fo r e A P C D ig L v l_ A fte r A P C
D ig lv l_ B e fo r e A P C 2 6 .6 7 2 5 8 8 3D ig L v l_ A fte r A P C 1 6 .1 3 2 9 8 2 3
40%
© ABB
| Slide 18 May 2, 2016
Case study : Mondi Swiecie, Poland Results: Digester chip-level control
• Stable blow flow
• Lower variations in
production rate MV
(measured)
• Improved cooking
conditions
• Stabilized downstream
washing process
Results Stabilized digester operations - blow flow
© ABB
| Slide 19 May 2, 2016
Customer Testimonials
• Mr. Tomas Katewicz (Member of Management Board & Production Director)
“…through their (ABB) APC, new and effective solutions have been implemented which are
stabilizing strongly the processes of the cooking and pulp washing lines.”
• Mr. Wojciech Jazdziewski (Pulp Mill Assistant Manager)
“ We do believe that the implemented MPC system will allow us to increase production output in a
stable way, whereas the high quality parameters of pulp will remain unchanged.”
“ I would like to express our appreciation to ABB for implementation and successful start-up of APC
for two production lines at Mondi Świecie S.A.”
• Senior Operator (more than 20 years at Mondi)
“ I have never seen in my life the chip level stabilize so beautifully.”
© ABB
| Slide 21 May 2, 2016
Contact information
If you have further questions, please contact me at:
Presenter : Abhijit Badwe
Company : ABB Pte Ltd
Contact phone : (+65) 9665-9947
Contact e-mail : [email protected]