Advanced Process Control for ARC
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1 Advanced Process Control Presented by Anil K. Choudhari
Transcript of Advanced Process Control for ARC
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Advanced
Process ControlPresented by
Anil K. Choudhari
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What is APC?
• APC = Advanced Process Control
• A traditional control system controls processes to fixed set points
determined by operators. Uses generic control algorithms and instructions
such as a PID controller.
• The purpose of an APC system is to automatically account for an
expected (modeled, predicted…) process response and calculate
“optimal” control actions to minimize process variation.
• APC systems utilize controllers and technologies such as
– Model based control
– Fuzzy logic and control
– Multivariable control
– Adaptive control
– Inferential control
– Process modeling and simulation
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Steam
PIC
Pressure SP
Typical Process Control
Flow
Density
FIC
Product
Inlet
Density
DI
Flow SP
Concentrate
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Advanced
Process
Controller
MV1
MV2
CV1
CV2
FV1
Steam
PIC
Advanced Process Control
FIC
Product
Inlet
Density
DIConcentrate
Flow
Density
Density SP
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The Business Challenges
Increased customer demands
Better quality
Greater quantities
Tighter specifications
Higher operating costs
Fuels
Energy
Personnel
Transportation
Increased competition
Internal capital
Other suppliersHow Can Your Business Flourish in this
Environment?
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Solutions for the Business Challenges
Economic benefits from APC
Throughput increase 4 - 10%
Yield increase 0.1 – 10%
Energy savings 3 - 10%
Variation reduction 20 – 90%
Reduce variation of key process and quality parameters
Increase plant capacity via tighter and smarter controls
React correctly and quickly to changing conditions
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Achieving Dairy
Manufacturing Excellence
using the APC
Milk Powder Solution Overview
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Issues & Trends
In the times when price of energy is increasing day by day & dairy plant is high energy consuming plant we should look into them first. One of the area can be the milk powder plant which is based on spray drying technology which is very costly way of reducing moisture from the milk.
Now a days many technologies are available to make the plant efficient but very few look into realizing process potential and achieve performance excellence with the help of automation available for industry.
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Benefits of APC
Advanced automation strategies help to ensure steady
performance of plants. Site analyses of Powder plant
indicate that the various parameters to be maintained are
not always steady.
Moreover the variations of a basic parameter have not always
been accompanied by corresponding proportionate
variations of other related parameters.
This has added to the instability in batch cycle time,
productivity and product consistency of Powder Plant.
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Commercial Benefits
By using advance automation, some of the tangible benefits derived can be :
– Increased Production of Valuable Products`
– Reduced Energy Consumption
– Predictable Process Performance
– Fewer Unscheduled Shutdowns, Improved Stability and Longer Equipment Life
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Pavilion8
Dryer Controller
Process (Manipulated Variables)
Uncontrolled Influences(Disturbance Variables)
Process Results(Controlled Variables)
Abs humidityFeed solids
Dryer Exhaust RH
Solids throughput
Product Moisture
Air flows
Setpoints(Manipulated Variables)
Uncontrolled Influences(Disturbance Variables)
Process Results(Controlled Variables)
Dryer Exhaust Temp
Dryer Inlet Air Temp
SFB Inlet Air Temp
Fluid Bed Inlet Temp
Abs humidityFeed solids
Dryer Exhaust RH
Solids throughput
Product Moisture
Air flows
Dryer Controller
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Spray Dryer application drying Cheese Whey
• Feed : 8000 Kg/Hr. processing with 9% final moisture
• 3760 Kg/Hr. solids
• Change in operational setpoints with use of Advance
automation
• Revised Final Moisture: 10%
• 1% increase in moisture due to better multivariable control
• 1% increase translates to 46 Kg/Hr. additional product (as
water)
• Assume dryer operation at 288 days/year, 24 hours/day
• ~6900 hours/year
• Total increase in production: 317 Tons/year
• Value of Increase: 250 – 317 Tons/year
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Commercial Benefits
• Key is price of product: $1.20 - $1.50/Kg…..or higher!!
• NFDM
• Cheese Whey
• Lactose
• WPC Powder
• Automation Sell Price: $300 - $400K
• Moisture Analyzers
• Software and associated APIs
• Design/Engineering
• Remote Support (optional)
• Payback: 9 - 15 months
This can be an eye opener if you really crave for energy in your country.
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Where the Technology stands today & how it works
More than 30 similar advanced control projects
have either been put in place or are in the
process of being installed in milk powder,
casein and cheese plants.
The technology permits operators to accurately
control factors that alter milk's quality and
consistency during the evaporating and drying
cycles.
Using models obtained from process data
allows to predict the future performance of the
plant, enabling correction before external
factors come through and affect the operation.
Process
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Additional benefits to the dairy which cannot be quantified
• Improvement in powder Quality by precisely controlling
moisture & bulk density of milk powder.
• Reduction in stack loss & improvement in environment.
• Reducing energy consumption by adaptive controls ( 3 to
10% savings)
• Quicker, more effective start - up.
• Reduces wastages & reworking by stopping choke-ups &
plant shutdowns.
• Improves thermal efficiency.
• Improves safety of plant
• Reduces fouling will reduce frequent requirement of CIP
• MIS, ERP & Energy management
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Market Leaders who believed APC
Consumer Goods Chemicals / PolymersCement
Biofuels
Minerals & Metals
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Cheese Cooker
Temperature
and
Moisture Control
Advanced Process Control (APC) Case Study
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Upstream Cheese
Supply
Controlled Variable
Manipulated Variable
Measured (known) Variable
KEY:
Temperature
Water Content
Water
Steam Pressure
Weight
Moisture
Recipe
Valve Position
Temperature
To Downstream
Processing
Additives
Weight
Moisture
Water Quantity
Generic Cheese Cooker Diagram
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Control Objectives
Control temperature in batch cookers
Achieve consistent product temperature profiles and batch times
Achieve consistent steam condensation in cookers
Achieve consistent, closer to target, final product temperature
Control product moisture
Achieve tighter and consistent control of downstream line moisture
Make model based adjustments between moisture lab samples
Consistent water addition adjustments per downstream line feedback
Temperature and moisture
Enable maximum possible line throughput
Enable maximum possible moisture content
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Business Objectives
OBJECTIVES ACTUAL RESULTS
Line throughput increase 7.6%
Yield increase 0.15% (based on moisture content only **)
Steam usage reduction 7.7% (less energy used)
Batch time reduction 13.5% (less time per batch)
Temperature variation reduction 40%
Operational benefits consistent control adjustments
consistent cheese quality
** Additional yield increase possible due to scrap/rework reduction
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Key Features of Temperature Control
Modeling
Dynamic heat/mass cooker model was developed and used to design, test
and evaluate control algorithms
Batch cycle temperature control
Constraint control (control final temperature to a minimum)
Control to multiple set points during different phases of cooker batch
Timing (follow batch logic to quickly satisfy conditions for next steps)
Expert (use expert set starting values for optimal initial conditions)
PID (instruction used for fast feedback corrections)
Steam valve manipulation (manipulated variable, actuator)
Controller tunable per recipe
Controller integrated in CLX/PLC, reusable code
Bumpless controller switching ON/OFF
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Key Features of Moisture Control
Modeling
Based on upstream sampling per cooker load
Mathematical model used for real time calculations
Controls
Model based compensation for upstream variation
Operator adjustments available (if needed)
Downstream line adjustments
Operator input: Set point (target) for product moisture
Output: water addition correction
Tunable magnitude of adjustments
Controller integrated in CLX/PLC, reusable code
Bumpless switching ON/OFF
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Final Product Temperature Before-After
Reduction of average final temperature and reduction of final temperature variation contribute to
downstream faster processing.
BEFORE AFTER IMPROVEMENT
AVERAGE minus MINIMUM 2 deg F 1.4 deg F 30%
STANDARD DEVIATION 1.4 deg F 0.7 deg F 50%
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Steam Consumption Before-After
Average Steam Consumption Reduction: 7.7%
Equivalent of: 68 PSIhours/day
DEC 04 = BASELINE
PS
Imin
Cooker #1: BLUE
Cooker #2: RED
Average: YELLOW
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Batch Time Before-After
Batch time improvements, RECIPE 1:
Batch time BEFORE: 255 seconds
Cooker #1 AFTER: 217 seconds
Cooker #2 AFTER: 228 seconds
Batch time improvements, RECIPE 2:
Batch time BEFORE: 200 seconds
Cooker #1 AFTER: 188 seconds
Cooker #2 AFTER: 188 seconds
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Moisture Control Before-After
Before After
Tests
Approximately 10-15% variation reduction, improved controllability.
Enabled moving the target to economically more favorable setting.
Target
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Industry Solutions
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Achieving Biofuel
Manufacturing Excellence
Using APC
Biofuel Solution Overview
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Ethanol Production
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Slurry Solids/Water Balance Control Application
Capabilities
– 50% reduction in slurry solids/pH variability
– Continuous management of fermentation gap increasing capacity and stabilizing plant to milling target
– Stabilize mineral/backset conditions to fermentation
– Manage process water toward global requirements/make-up
Benefits
– Increase ethanol yield (~2% gal/bu)
– Increase fermentation capacity (MMGPY)
– Increase enzyme effect (enzyme/gal)
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Methanator
Slurry Tank
Process Water
Liquefaction
Backset
Beer Feed
Milling
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MethanatorMethanator
Slurry Tank
Process Water
Liquefaction
Backset
Beer Feed
Milling
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Fermentation Control Application
Capabilities
– 50% reduction in batch EtOH and dextrose/residual sugars variability
– Continuously manage enzymes to maximize throughput and ethanol yields
– Optimal target on temperature and pH for fermentation
– Manage fermentations to match production targets
Benefits
– Increase in batch drop ethanol yield (MMGPY) by 0.5-1.0%
– Increase in fermentation capacity by 5-12% (MMGPY)
– Increase in batch yields (gal/bu) by 2-5%
– Reduce enzymes/gal ($$ enzymes/gal) by 5-10% 8
Slurry Tank
Liquefaction
Backset
Beer Feed
FermenterYeast Propagation
Enzymes
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Slurry Tank
Liquefaction
Backset
Beer Feed
FermenterYeast Propagation
Enzymes
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Beer Feed
Evap. Steam
Steam Flow
Sieve Back
Pressure
Rectifier Reflux Sieve Feed
Vaporizer Temperature
Beer Feed
Evap. Steam
Steam Flow
Sieve Back
Pressure
Rectifier Reflux Sieve Feed
Vaporizer Temperature
Distillation / Molecular Sieve Application
Capabilities
– Integrate non-linear models, multivariable control and advanced optimization in one algorithm
– Control distillation to optimum moisture
– Control end-product moisture to the desired specifications
Benefits
– Increase Ethanol production capacity 3-10%
– Increase ethanol yield by .1-.2%
– Reduce energy use/gallon by 1-2%
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Dryer Control Application
Capabilities
– Direct targeted control of Syrup Solids and DDGS moisture
– Continuous management of dryer capacity (centrifuge feed) against dryer operating limits (moisture, temperature, gas)
– Balance dehydration energy between evaporation and drying
– Reduce Overdrying, stabilize dryer and reduce energy consumption/ton
– Stabilize plant steam and thermal oxidizer thermal destruction temperature against operating limits
Benefits
– Increase average DDG yield of 1-1.5%
– Reduce energy costs per gallon of ethanol produced by 2-4%
– Reduce product moisture variability by more than 50%
Steam Flow
Centrifuge Feed
Whole Stillage
Thin Stillage
Syrup Tank
Wet Cake
Pad
Steam Flow
Centrifuge Feed
Whole Stillage
Thin Stillage
Syrup Tank
Wet Cake
Pad
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Benefits of APC Are Substantial for Ethanol Manufacturers
Revenue
3 – 6%2.5 – 5% 1 – 2%5 – 8%
Reduce energy costs (BTU/gal)Improved ethanol yields (gal/bu)Improved DDGS yields Reduce enzyme usage (gal/Kgal)
Operating Cost
2 – 10% Increase production volume (MMGPY)
% IMPACTESTIMATED BENEFITS
Typical Project Payback < 6 mo.Typical Project ROI > 200%Project Duration 4-12 months
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APC Project Flow
Enhance Profitability
– Increase Production
• Unlock capacity
• Maximize throughput
– Reduce Manufacturing Costs
• Use less energy per unit of output
• Maximize alternative fuels use
– Improve Product Quality
• Minimize variability
• Reduce deviation from
specifications
– Reduce Environmental Risk
• Achieve active emissions
compliance
• Support emissions trading
