Conoco on Path to Reliability Centered Loop Management: Enhancing ROA on the Way

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Conoco on Path to Reliability Centered Loop Management: Enhancing ROA on the Way
Process manufacturers have invested heavily in manufacturing plants and
automation systems. A typical manufacturing plant may have hundreds or
even thousands of regulatory control loops to enable safe and efficient operations.
The most complex units often have advanced process control and
optimization schemes implemented on top of these regulatory control
loops. All of these systems have a need for
tighter process control to enable more effective
use of assets that result in higher ROA and ultimately
better business performance and
profitability.
Unfortunately, automation effectiveness deteriorates
over time. The lack of a structured
methodology for control loop maintenance is a
contributing factor that erodes performance. A
manufacturing plant typically has only two or three control engineers who
each have responsibility for a large of number of loops, yet they often have
no means of identifying where to focus their efforts so that their work has
the largest economic impact on plant performance.

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Conoco on Path to Reliability Centered Loop Management: Enhancing ROA on the Way

  1. 1. THOUGHT LEADERS FOR MANUFACTURING & SUPPLY CHAIN ARC INSIGHTS By Tom Fiske Most manufacturers are not extracting all the value possible from their assets. Even small incremental improvements can fall straight to the bottom line. The lack of a structured methodology for control loop maintenance is eroding ROA. Conoco has adopted a Six Sigma approach that helps its overburdened staff locate and fix the most economically beneficial problems while avoiding unnecessary and costly repairs. INSIGHT# 2003-11MP FEBURARY 20, 2003 Conoco on Path to Reliability Centered Loop Management: Enhancing ROA on the Way Keywords Asset Management, Control Loop Monitoring, Operational Excellence (OpX), Return on Asset (ROA), Reliability Centered Maintenance (RCM) Summary Process manufacturers have invested heavily in manufacturing plants and automation systems. A typical manufacturing plant may have hundreds or even thousands of regulatory control loops to enable safe and efficient op- erations. The most complex units often have advanced process control and optimization schemes implemented on top of these regulatory control loops. All of these systems have a need for tighter process control to enable more effective use of assets that result in higher ROA and ul- timately better business performance and profitability. Unfortunately, automation effectiveness dete- riorates over time. The lack of a structured methodology for control loop maintenance is a contributing factor that erodes performance. A manufacturing plant typically has only two or three control engineers who each have responsibility for a large of number of loops, yet they often have no means of identifying where to focus their efforts so that their work has the largest economic impact on plant performance. Conoco has adopted a Six Sigma Operational Excellence (OpX) approach to loop assessment and maintenance. They are using Loop Scout from Hon- eywell to continuously measure, analyze, improve, and control their loop performance. At their initial pilot refining site, they have reduced energy costs by identifying an oscillation of six interacting loops in the fuel gas sys- tem of heaters that feed two crude units. Repairing the malfunctioning pressure valve resulted in a savings of $500k per year. They are currently adopting a Reliability-Centered Maintenance (RCM) strategy that helps de- termine the appropriate maintenance response based upon the consequence of failures. Conoco’s saving in turnaround avoidance greatly exceeds its energy savings.
  2. 2. ARC Insights, Page 2 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com Analysis One of the defining characteristics of the process industries is the utilization of asset intensive manufacturing operations and consumes large quantities of raw materials and energy to produce products. ROA is often used as a key measure of operational performance because it indicates how well a company uses its assets to generate income. The manufacturer’s most criti- cal challenge lies in improving ROA by managing its assets, material, and energy usage in the most effective way possible. Control Loop Maintenance Is Crucial to Increasing ROA The economic benefits that automation and control systems have bestowed on manufacturing operations are undeniable. However, automation sys- tems operations require effective regulatory control. Unfortunately, this is not always this case due to poor loop tuning, equipment problems, or im- proper control strategies. For example, Honeywell has analyzed over 250 thousand control loops and found that only one-third have acceptable vari- ability transfer performance. Even if a process were running at optimal economic conditions, performance deterioration occurs from changes in production objectives, wearing of equipment, etc. Organizations must be constantly vigilant to prevent control loop variabil- ity transfer performance deterioration since they are essential to operating the plant effectively. However, control loop performance monitoring and maintenance is a balancing act; doing too much can waste time and money while doing too little can cause poor variability transfer performance and unscheduled downtime. Since control engineers are typically responsible for hundreds of control loops, it is not possible or even advisable to attempt to have all your loops run optimally since the time, effort, and expense are prohibitive. Users need tools to help them achieve a good balance by point- ing out which control loops under the current situation provide the largest benefit when running optimally. RPM Systems –Provide Information When it Is Needed While automation has fostered significant operational improvements, the best results occur when highly skilled workers augment automation and control systems with their knowledge, skills, and experience to manage plant performance. At the ARC Driving Operational Excellence in Manu- facturing Forum held this month, the overwhelming consensus of presenters was that providing pertinent and timely information to opera- tional personnel is a critical success factor in improving performance.
  3. 3. ARC Insights, Page 3 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com One of the key elements needed to aid process manufacturers in their quest to increase profitability is a Real-time Performance Management (RPM) sys- tem. RPM systems leverage the wealth of information contained and generated by process automations systems while supporting continuous improvements and OpX tenets. For an RPM system to reach its true poten- tial, current performance information must be made available in a time frame that is consistent with the job employees do. It is imperative to de- liver the right information to the right person at the right time and in the right context so that he can take the right actions within the production cy- cle to improve plant performance. The information must be incorporated into the workflow process so that actionable items are easily derived and generated from the associated analysis. Loop Scout Delivers at Conoco About two years ago, Conoco (now ConocoPhillips) began using Loop Scout, a loop monitoring and reliability centered maintenance solution from Honeywell. The initial pilot application was at its Denver refinery. The facility is a small refinery with a capacity of 58,000 BPD and produces a slate of petroleum products marketed in Colorado. Conoco recognizes the benefits of having a strong asset management program. Conoco believes they can increase operational performance and decrease maintenance cost by applying asset management techniques to control loops. Consequently, a joint Six Sigma project was initiated between Conoco and Honeywell to optimize control loop maintenance. The initial objective was to have all their control loops run optimally. After further contemplation, however, they decided that was just not feasible. Instead, a more reason- able objective was declared: to optimally deploy maintenance resources. The facility has 642 control loops and a small staff that shared ownership among engineering, operations, and maintenance. Buy-in for the project was obtained from all three groups so that workflow processes could be coordinated since the results impacted everyone. A Six Sigma DMAIC (De- fine, Measure, Analyze, Improve, and Control) work process for their control loop assessment and maintenance was developed over six weeks. As part of the Define and Measure step, Loop Scout was used to collect per- formance data on all 642 control loops. Loop Scout computes approximately 10 performance metrics to help identify the greatest business performance improvement opportunities by finding where major problem areas exist. The performance of each loop is categorized as excellent, ac- ceptable, open loop, fair, or poor. Applying their process knowledge,
  4. 4. ARC Insights, Page 4 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com Conoco assigned each loop to a criticality level that reflects its importance in terms of the economic impact it has on the plant. Of the 642 control loops, it was determined that 153 had high economic impact on the plant. During the analysis step, all loops are prioritized based upon a combination of its performance and criticality to generate a narrowly focused opportu- nity list of economically significant, poor performing subset of control loops. The importance of this step cannot be over emphasized, since finding the right loops that have a high impact on business performance is difficult. Loop Scout pro- vides another set of metrics and performs detailed diagnostics to determine the root cause of the problem so corrective actions can be taken. This is often difficult, as a problem can have several causes each con- tributing to poor performance. Loop Scout’s reports are generated as needed from continuous plant data in time for employees to perform their functions. Since it is a service, it does not overload Conoco’s staff. The reports put the metrics in the proper context to show why a loop is at the top of the list, how it has changed over time, and how its performance is related to other assets. Al- most immediately, a 33 minute oscillation of six control loops in the fuel gas system (highly critical with fair performance) of the two four-pass heaters that feed two crude towers was identified. Loop Scout diagnostic metrics indicated that a pressure valve stiction problem was the most likely culprit. A work order package was issued to fix the problem as part of the DMAIC improve step. The unit was taken offline, the pressure valve repaired, and the loops retuned. Validation of the improvements was also done using Loop Scout. The resulting cost savings in the reduction of fuel gas was close to $500k/year. Throughout the following year, numerous opportuni- ties arose, such as the identification and repairing of 12 sticky valves, which contributed to APC downtime and decreased yields on the FCC unit. With the success of the pilot project behind them, Conoco is rolling out Loop Scout to three other refineries. Today, Conoco continues to periodically scan and monitor loops with Loop Scout to ensure they perform effectively. In addition, Conoco’s greatest Repair / Replace Measurement Device Repair / Replace Measurement Device TuneControllerTuneController Investigate andRepair Valve Investigate andRepair Valve Reactive Maintenance WorkOrders fromOps Reactive Maintenance Work Orders fromOps Developand Execute Work Packages Develop and Execute Work Packages Sort and Prioritizebased on Performance andCriticality Sort and Prioritizebased onPerformance andCriticality AssessRepair Effectiveness AssessRepair Effectiveness Assess Performance, Stiction, Common Oscillations, Tuning Changes Assess Performance, Stiction, Common Oscillations, Tuning Changes AssessCriticalityUsing RankingMethod AssessCriticalityUsing RankingMethod Implement Criticality- based Schedule Implement Criticality- based Schedule Collect Time SeriesData LegendLegend RecurringHuman Activity RecurringHuman Activity Automatic Activity Automatic Activity One-timeHuman Activity One-timeHuman Activity TrackBenefits usingSix SigmaMethods TrackBenefits using Six Sigma Methods Set Benefits Targetsand Expectations Set Benefits Targetsand Expectations Implement a Six Sigma Control Plan that Drives and Maintains Optimal Loop Management
  5. 5. ARC Insights, Page 5 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com cost savings (greatly exceeding its energy saving) has come from turn- around avoidance by eliminating unnecessary repairs. This alone represents such a large savings opportunity that they are moving toward adopting a RCM program. RCM combines the elements of reactive, pre- ventative, and predictive maintenance while providing higher reliability at a lower total cost. In essence, RCM examines the consequences of failure to determine the appropriate maintenance requirements. Workflow Method Feature Comments Reactive As needed Low initial cost, no advanced failure warnings, can result in production problems and high opportunity cost Preventative maintenance Time based Low initial cost, no advanced failure warnings, often perform unnecessary maintenance, highest TCO Predictive maintenance Condition based Need based maintenance, predicts failure, requires special equipment, higher initial costs than preventive maintenance – but lower TCO Reliability Centered Combination of above Considers consequence of failure to determine appropriate level of maintenance, lowest TCO, provides highest reliability Maintenance Methodologies Recommendations • There is an enormous amount of unrealized performance remaining in manufacturing assets. A best practice and continuous improvement strategy is the best way to realize this performance. One prime area to exploit is control loop performance. • Manufacturers must adopt a comprehensive OpX program that pro- vides a coordinated plan to perform maintenance on control loops to ensure optimal performance and increase ROA. Since resources are limited, it requires a sound maintenance strategy based upon knowl- edge generated from a comprehensive surveillance program to indicate the most economically beneficial opportunities. Please help us improve our deliverables to you – take our survey linked to this transmittal e-mail or at www.arcweb.com/myarc in the Client Area. For further information, contact your account manager or the author at tfiske@arcweb.com. Recommended circulation: All MAS-P clients. ARC Insights are published and copyrighted by ARC Advisory Group. The information is proprietary to ARC and no part of it may be reproduced without prior permission from ARC.

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