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Energy Seminar

Energy Seminar. Emerson Process Management June 22/23, 2010. Process Control Fundamentals. Kurt Schmelzer & Tom Marsh Novaspect, Inc. Process Control Applies…. Purchased Steam. Process Steam Drives. Export Steam. Central Steam / Water Production. Purchased Fuel.

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Energy Seminar

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  1. Energy Seminar Emerson Process Management June 22/23, 2010

  2. Process Control Fundamentals Kurt Schmelzer & Tom Marsh Novaspect, Inc.

  3. Process Control Applies… PurchasedSteam ProcessSteamDrives ExportSteam Central Steam / Water Production PurchasedFuel ProcessHeating/Cooling ProcessSteamGenerated Water Raw Material as Fuel ProcessFiredEquipment ExportFuel ProcessDirect FuelUsage ProcessMisc. Electric / Air Usage Central Power / Air Production ExportPower Utility Plant PurchasedPower ProcessElectricDrives Site Processes

  4. Causes of Variability Loops The Cause Loops The Cause Design Design 20% Design Tuning Tuning 30% Increases Variability Increases Variability Control Valve Performance Control Valve Performance 30% As Many As 80% of Loops Actually Increase Variability 20% Source: Entech---Results from audits of over 5000 loops in Pulp & Paper Mills

  5. Main Steam Temperature Control Decreased Variability = Increased Profit Upper Limit • NPHR • = 0.75% • Reduction Set Point SUPERHEAT TEMP. Increased Temp. Set Point Reduced Process Variability Provides the Opportunity for Setpoint Change = ( NPHR) X Fuel cost X KW-HR generated/year = Savings = .75% x 11,000 BTU/KW-HR X $2.22/MM BTU X 320,000 KW X 8760 hours / year = $516,517 per operating year !!

  6. The Energy Improvement Process Begin Survey and Measure Minimal Capital Cost Implement Site Management Fix Devices and Loops Optimize Unit Processes Address Equipment

  7. Practical Process Control • Basics of Process Control • Keys for Boiler Control • Keys for Chiller Control

  8. Measurements Final Control Elements Controller Control Strategy Correct for application Correct for application Set-up and Tuning Designed to the system Basics

  9. Basic Controls Can Save Energy Upper Limit Set Point Increased Set Point Lower Limit • What is the key to capturing the performance of measurements and final control elements STRATEGY&TUNING

  10. Boiler Control

  11. Boiler Control Measurements Keys • Drum Level • Accuracy, and Reliability • Fuel Flow • Repeatability, and Reliability • Air Flow • Repeatability, and Reliability • Flue Gas Oxygen • Accuracy, and Reliability • Steam Flow • Accuracy, and Reliability • Feedwater Flow • Accuracy, and Reliability

  12. Boiler Control Controller Keys • Controller/s capable of handling the highly interactive boiler process • Fast enough to unlock the performance for the measurements and final control elements. Typical 0.5 Sec. • Digital Resolution equal to the field instrumentation 32 Bit floating point required

  13. Energy Saving Control Strategies Stack O2 Trim Ensures you maximize energy savings

  14. Tuning

  15. Tuning– Coordinated Lambda

  16. Tuning – Cross Limit Effect

  17. Boiler Control Tuning • Open Loop Bump Testing • Air & Fuel are Self Regulating Processes • Maximize Speed of Response • Improve performance by coordinating response to maintain fuel/air ratio through load changes • Optimize to lower O2 as control improves. • Understand what your O2 reading Represents. • Determine CO Limits • Feedwater Flow is a Self-regulating Process • Maximize Response as this is the inner loop • Drum Level is an Integrating Process • Average of Several Slopes to get best response.

  18. Chiller Plant Overview

  19. Chiller Overview

  20. Cooling Towers

  21. Sequencing

  22. Chiller Control Measurement Keys Temperature Accuracy, and Reliability Temperature Accuracy, and Reliability Temperature Accuracy, and Reliability Water Flow Accuracy, and Reliability

  23. Key Final Control Elements Compressor Guide Vane Actuator Child Water Flow Refrigerant Level Reduce Varability

  24. Temperature Control Tuning • Open Loop Bump Testing • Self Regulating Process or Near Integrating Process • Ensure self regulating process has reached final temperature • Improve performance by treating as integrating process • Dead Time • Chiller on-board loops should have relative short dead-time • System loops may have significant dead-time • Dead time approach – PID, Model Predictive, Smith Predictor • Sequencing • Control of the Various Redundant Systems

  25. Optimization is a Building Process Sustainable Business Results Are at Risk if a Holistic Approach is Not Utilized SOP Tuning Optimize Unit Process Math and Model Adjustment Control Platform and Single-Knob Automatic Regulatory Fix Devices and Loops Process Measurement Process Actuation Address Equipment Process Issue Resolution / Mitigation

  26. Single Knob - Control • Attention to fundamental are the keys. • Robust fundamental controls are the foundation to energy management solutions.

  27. The Takeaway Ineffective controller tuning is the biggest single contributor to poor control loop performance and energy waste …stay focused on Loop Tuning!

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