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Newsletter 2006 issue 3 |
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Assessing Steam Traps
Steam traps are automatic valves that release condensed steam (condensate) while preventing the loss of live steam. Facilities can have numerous traps and many are hidden along pipeline highways. With the mechanical stress of frequent opening and closing—traps fail. When they do, energy goes to waste.
Trap ranking
Prioritize steam traps for management by their potential for energy loss when they blow:
- High pressure distribution, 24/7 operation, boiler room
- Low pressure distribution
- High pressure modulated: process heat, ovens, high temperature fluid heat
- Low pressure modulated: comfort heating, buildings, potable water
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According to the U.S. Department of Energy, if steam systems that have not been maintained for three to five years, 15 to 30 percent of their traps may have failed. In systems with a regularly scheduled maintenance program, leaking traps should account for less than five percent of the traps.
MnTAP recently conducted a steam trap assessment at the Metropolitan Council Environmental Services (MCES) St. Paul wastewater treatment facility, assessing over 91 high-pressure traps to demonstrate the payback of steam trap assessments. Nearly one-third of the traps were malfunctioning—either losing steam (blowing) or flooded or plugged, costing the facility over $7,000 annually.* The assessment findings underscored the value of more-frequent trap testing and continuous monitoring of critical traps.
Energy assistance
Xcel Energy funded the assessment as part of a pilot promotion through its Boiler Efficiency program, ConservationWise. The promotion aims to encourage Xcel Energy’s natural gas customers to perform routine maintenance on steam distribution systems to improve energy efficiency. The utility also provides rebates for materials used to repair or replace non-functioning traps.
Check with your gas utility to see if it offers similar rebates.
Trap testing
Economic analyses shows that the cost of testing steam traps and repairing and replacing them is generally less than a one year payback.
MnTAP staff use ultrasonic listening instruments, infrared temperature measurement and visual inspection of trap discharge to diagnose the condition of steam traps. Company maintenance staff would use these same tools when conducting their routine trap management inspections.
Call MnTAP to request a steam trap assessment demonstration at your facility.
* MCES derives energy from an, eh hem, alternate fuel source that is delivered regularly by pipeline to its facility. Using the wastewater treatment sludge helps decrease the natural gas needed to generate steam.
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