Tales from the Road: Ultrasonic Leak Detection Survey Experiences at Industrial Plants, Part 2

January 30th, 2015

In the first installment of this 2-part series, we heard how Vernon Guidry of DuPont leveraged ultrasonic tools to locate, fix and prevent costly compressed gas leaks. Speaking to an audience at the Ultrasound World XI Conference of 2013 in Clearwater, Florida, Guidry walked through DuPont’s leak survey process while focusing on energy and fiscal savings.

Since 2006, the company has conducted a wide array of surveys at 135 plants and recommended using the same leak detection and prevention solutions that saved these factories significant amounts of money and energy. In this second part, Guidry turned his attention to steam leaks, which can pose similar problems to compressed gas leaks and require diligent attention.

Steam systems overview
Using the same ultrasonic leak detection tools as those used for compressed air leaks, DuPont also surveys steam systems and components at their plants. These surveys analyze generation facilities, thousands of running feet of distribution piping, hundreds to thousands of steam traps, a mixture of steam trap applications in utility and process areas and various other

In surveying steam systems, inefficiency and steam loss are the two obvious areas of concern. But ultrasonic tools can also be used to improve existing steam systems. Even effective steam trap and steam condensate systems can be improved upon using best practice application. There are also opportunities to re-use condensate in a boiler or steam generator rather than bringing in new water and treating it. DuPont looks at misapplication or poor, inefficient utilization of steam.

Steam trap failures can also be a safety hazard for industrial plant employees. Surveys provide an opportunity to identify potential safety, mechanical integrity or design issues. Hydraulic shock or water hammer can cause equipment failure while blown valves can burn and injury nearby employee. Improper ventilation and discharge areas can also be unsafe and environmentally detrimental. Steam leaks can also corrode any piping and fitting it comes in contact with along with adjacent piping that comes in contact with condensate. Leaks can be loud and cause hearing damage for someone in close proximity to the site of the steam trap. All of these are problematic results that can be prevented through ultrasonic leak detection.

Stream traps will and do fail – it’s a matter of detecting and repairing the failures while simultaneously using predictive maintenance techniques find the potential defects before they become problematic. Regular surveys can prevent failures from taking shape.

Steam trap survey process
The techniques DuPont employs to find steam leaks are similar to those used for compressed air leak detection. DuPont uses three test methods for steam traps: sight, sound and temperature. Visually, infrared cameras provide insight that the eye cannot catch.Ultrasound leak detection is used for the duration of the survey.

When the defective steam traps and leaks are discovered, Guidry’s team hangs a Red Trap Leak tag at the point of malfunction. Then, the defect is logged in a survey spread sheet for work order generation and cost avoidance calculations.

The Site Energy Champion or Reliability Engineer is responsible for ensuring the leak notifications reach SAP for repairs. Finally, once the repairs are made, the Red Trap Leak tags are returned and the spread sheet is updated. Using this systematic, step-by-step approach and with the help of vibration condition monitoring, DuPont is able to effectively repair leaks in a timely and orderly fashion.

Steam leak survey data
Since 2006, DuPont conducted 59 steam trap and steam systems leak surveys. The company found roughly 993.5 million pounds of steam loss per year, or 16,200 pounds per hour. That led to approximately $6.5 million worth of lost energy annually. Additionally, steam loss from leaks totaled over 523 million pounds per year or 8,530 pounds per hour – a value of almost $4 million. These steam leaks also led to over 34,503 tons of carbon emissions and a loss of over 68 million gallons of water.

In 2012 alone, DuPont carried out 14 steam trap and steam system leak surveys. From steam trap leaks, they found over 232 million pounds per year or around 26,500 pounds per hour of steam loss. That loss equated to roughly $1.4 million per year. On average, 14.43% of steam traps tested on the 14 sites failed. From steam leaks, DuPont calculated that plants lost over 105 millions pounds per year or 12,000 pounds per hour of steam loss. Those losses were equivalent to $641,000 per year. Altogether, DuPont found 5,953 tons of carbon emissions and 11.8 million gallons of water loss.

From 2012 alone, DuPont could have purchased and operated a 1,200 horsepower boiler with the money lost from steam leaks and failed steam traps.

Personnel training
Guidry pointed to the integral role that proper ultrasonic plant maintenance training played on DuPont’s ability to carry out steam strap surveys. Surveyors and steam trap maintenance personnel must be trained. The ability to effectively apply ultrasonic leak detection in areas where system components are difficult to access is invaluable. A lack of awareness or misuse of equipment can lead to more defects in the steam trap system.

Faculty can take training sessions – even a one- or two-day training class can make a huge difference in surveyors’ understanding of plant maintenance. Training involves an introduction to the probes and instruction in the field. These classes also let surveyors hear the actual sound of a defect so when they encounter one in the plant, they know how to react. DuPont also incorporates education session from the steam trap vendors and the equipment manufacturers to offer additional insight.

There are also online courses anyone can take to gain certification in ultrasound leak detection application and best practices, or just to glean a better knowledge of the technology.

Tutoring goes beyond just the surveyors – the entire plant should have at least a baseline understanding of ultrasonic leak detection surveys so that the day of the survey, everyone will know what to expect.
Click here for Part I

Suggested Ultraprobe Instruments for leak surveys: Ultraprobe 3000; Ultraprobe 9000: Ultraprobe 10,000; Ultraprobe 15,000

 

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