Slide 3 Speaker George Buckbee is a veteran of the process control industry, and a widely-known expert in the field of process control performance measurement. George has over 25 years of practical experience improving process performance in a wide array of process industries, including Oil & Gas, Pulp & Paper, Pharmaceuticals, Utilities, and Consumer Products. George is an ISA Fellow, and he holds a B.S. in Chemical Engineering from Washington University, and an M.S. in Chemical Engineering from the University of California, Santa Barbara.
Slide 4 Control Improvements Provide the Foundation for APC Success Abstract 50% of APC results can come from improvements to fundamental regulatory controls. Advanced Process Control (APC) is software that manipulates the underlying regulatory controls to drive the process toward optimum profitability. But the APC system needs a solid foundation on which to build. The Regulatory controls must be in good working order, or the APC system will be wasting time and money. This presentation describes both time-honored and novel approached to improving the regulatory control layer. This includes automated evaluation of instrumentation, valves, process, and control performance. Specific prioritized diagnostics will be demonstrated. The presentation will conclude with a documented case study showing bottom-line results through both regulatory improvements and APC.
Slide 5 Contributors Mayankumar Shah, RasGas Tom Kinney, Invensys
Slide 6 Invensys / ExperTune A Long-Term Partnership Invensys Sales Services Expertise –Customer Process –Process Control –Field Expertise ExperTune Software Expertise –Control Performance –Training –Support
Slide 7 Why Bother with Regulatory Controls? Temperature ValvesDampersDrivesHeaters FlowPressure Single-Loop Control CascadeRatioFeed Forward APC
Slide 8 The Basics of Control Performance 1.% Time in Normal Mode 2.Control Valve Operation 3.Instrumentation 4.Controller Tuning 5.Oscillations
Slide 10 Work Process – Regulatory Loops AssessAll Control System Components BaselineBusiness MeasuresTechnical Measures Document ResultsBusiness MeasuresTechnical Measures Prioritize Between LoopsWithin Loops ResolveAccording to Priority
Slide 11 Assessment Example: Service Factor Is the Controller Controlling? In the Proper Mode? Valve in a Controllable Range? Process Variable in Limits? Within Spec Limits? Within X% of Setpoint?
Slide 12 Prioritize: Biggest Payback Loops Where are the biggest opportunities? Technical Factors Economic Factors
Slide 13 Resolve: Diagnostics & Specifics What Exactly is Wrong? Biggest Issue with Each Loop Other Issues Quantify the Issues Back-up Information How to Resolve
Slide 14 Resolve: Expert Advice What Exactly is Wrong? Understand the Issue Action Steps Get Expert Advice
Slide 17 Project Background High levels of flaring from the Train 3 Fuel Gas system have historically been considered normal. Inconsistent with ADGAS current environmental commitments. Invensys were awarded a FEED study to: Evaluate root causes Define appropriate solutions
Slide 18 Invensys FEED study outcomes Fuel Gas demand is significantly variable: 65 kNm3/h to 80 kNm3/h Excessive flare volumes are due to a lack of inventory management around the Fuel Gas system: Supply to the system not matched with demand Principal Recommendation: Implement multivariable model-predictive control for inventory (pressure) control and minimization of variability.
Slide 19 Control Loops are Economic Assets Train-3 Study shows that… 15% of control loops were oscillating 33% had controller output at limit 27% had excessive valve travel 20% involved high variability 19
Slide 20 39PDC8074 Before Tuning Mean Std.Dev. SPT 0.7 N/A PV 0.719 0.018 O/P 77.6 1.032 After Tuning Mean Std.Dev. SPT 0.68 N/A PV 0.6835 0.0084 O/P 76.8 0.309
Slide 22 Pre- and Post-Project Flaring Comparison Results Sept-Oct 2007 Sept-Oct-Nov 2008 Basic Control Improvements APC Implementation
Slide 23 Results Invensys proposal guaranteed a 75% reduction in flare gas. Actual result was 84% Total reduction worth approx. => $3MM/yr+ APC (model-based predictive control) has achieved a very significant impact on Das Island environmental emissions
Slide 24 Conclusions 1.The Regulatory Layer is Key to APC Success. 2.There are Many Opportunities at the Regulatory Layer. Instrumentation Valves Controls 3.A Proven Approach to Results: Field Engineering Expertise with PlantTriage Control Performance Monitoring
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