Boiler Safety Valves: Practical Guidelines for Maintenance Planning

Jim DomitrovichTerritory Manager

Consolidated® Pressure Relief Valves

August, 2008 • Harrisburg, PA

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Evolution of Boiler Technology

•On-going boiler enhancements have enabled safe and efficient use of boilers in power generation

•Development of the safety valve promoted boiler evolution

• Valve advancements increased control to reduce risk

• Most important safety device on a boiler or pressure vessel

• Last line of defense in overpressure situations

• Protects employees, equipment and environment

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The Role of Dresser Consolidated

•130+ year history with pressure relief solutions for the power generation industry

•Expertise and application knowledge

• Commitment to safe, efficient boiler operation

• Address unique challenges from any application

• Support from initial design phase through long-term

maintenance programs utilizing our GTC Network

•Elevating valve performance by elevating the level of customer care

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Safety Valve Maintenance

•Critical to safe and efficient boiler operation

•Decreases cost of ownership

•Development of a safety valve maintenance program can be a challenge

• Varied operating conditions

• Physical location of valve within plant/boiler

• Determination of operating gap

• Materials used for stack piping, drip pans, condensate drains, etc.

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Safety Valve Maintenance

How often should I inspect or repair my safety valves?

Repair intervals for boiler safety valves should be . . .

“determined by operating experience.” The National Board Inspection Code Section RB-8410

At the user level, this statement can be hard to define without knowledge of numerous operating factors.

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An innovative solution from an industry expert

Safety valve maintenance tool Interactive CD Created for boiler applications Template for developing in-house

maintenance programs Evidence-based approach Defines “factors” that must be considered Based on real-life condition

Predicts an estimated repair / maintenance interval

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Estimated Repair Interval

•Contributing factors for safety valve condition identified

• Each factor assigned a weight• Based on operational knowledge and

actual repair experience

• Select factor from drop down list• Example: Operating Gap

• Continue to populate factors

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Competitive Comparisons

•Total combined factor weight populates automatically

•For this application, factor weight is 48

•Click on “Estimate Repair Interval”

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Estimated Repair Interval

• For this valve, the estimated repair interval is approx. 14 months• Reasonable estimate for repair intervals of boiler safety valves

• Based on real life factors that define the National Board’s reference

to “determined by operating experience”

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Safety Valve Failure

• A number of factors can contribute to safety valve failure• Not opening at set point

• Not achieving full lift

• Not closing after reaching blow-down value (Hang-Up)

• Valve leakage

• Not opening at all (Worst scenario)

• Planning a maintenance program using the CD tool can help avoid these failure factors

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Conclusion

• Benefits of planning for inspection, maintenance and repair• Identification of operational trends

• Improves access to critical valve data (Valvkeep)

• Assists in trouble-shooting

• Manages repair process workflow

• Provides details for compliance reports

• Helps prevent costly valve failures

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Conclusion

Any questions?