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© 2010 Invensys. All Rights Reserved. The names, logos, and taglines identifying the products and services of Invensys are proprietary marks of Invensys.

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Presentation on theme: "© 2010 Invensys. All Rights Reserved. The names, logos, and taglines identifying the products and services of Invensys are proprietary marks of Invensys."— Presentation transcript:


2 © 2010 Invensys. All Rights Reserved. The names, logos, and taglines identifying the products and services of Invensys are proprietary marks of Invensys or its subsidiaries. All third party trademarks and service marks are the proprietary marks of their respective owners. Control Improvements Provide the Foundation For APC Success Session Name: SimSci-Esscor Solutions Session ID #: PBSS311 Presented by George Buckbee 11/09/11

3 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.

4 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.

5 Slide 5 Contributors Mayankumar Shah, RasGas Tom Kinney, Invensys

6 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

7 Slide 7 Why Bother with Regulatory Controls? Temperature ValvesDampersDrivesHeaters FlowPressure Single-Loop Control CascadeRatioFeed Forward APC

8 Slide 8 The Basics of Control Performance 1.% Time in Normal Mode 2.Control Valve Operation 3.Instrumentation 4.Controller Tuning 5.Oscillations

9 Slide 9 Performance Assessment

10 Slide 10 Work Process – Regulatory Loops AssessAll Control System Components BaselineBusiness MeasuresTechnical Measures Document ResultsBusiness MeasuresTechnical Measures Prioritize Between LoopsWithin Loops ResolveAccording to Priority

11 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?

12 Slide 12 Prioritize: Biggest Payback Loops Where are the biggest opportunities? Technical Factors Economic Factors

13 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

14 Slide 14 Resolve: Expert Advice What Exactly is Wrong? Understand the Issue Action Steps Get Expert Advice

15 Slide 15 Case Study - RasGas, Das Island

16 Slide 16

17 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

18 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.

19 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

20 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

21 Slide 21 21 Assessments: before and after tuning Key Performance Before TuningAfter Tuning Avg.% to Threshold 72.0647.32 Variability – KPI Variability - %T Variability - %E 4.423 147.4% 73.71% 2.593 86.42% 43.21% Avg.absolute Error – KPI Avg.absolute Error - %T Avg.absolute Error - %E 1.338 26.76% 13.38% 0.5325 10.65% 5.325% Output Std.Deviation - KPIOutput Std.Deviation - %T Output Std.Deviation - %E 0.8383 16.77% 8.383% 0.3103 6.206 3.103% Valve Travel – KPI Valve Travel - %T Valve Travel -%E 34550 138.2% 69.1% 3448 13.79% 6.895% Valve Reversal - KPI Valve Reversal - %T Valve Reversal - %E 25220 50.43% 25.22% 6726 13.45% 6.726%

22 Slide 22 Pre- and Post-Project Flaring Comparison Results Sept-Oct 2007 Sept-Oct-Nov 2008 Basic Control Improvements APC Implementation

23 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

24 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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