I recently did something that I normally don’t do.
My family has a couple of upcoming trips that will entail driving across a few states on consecutive weekends. The vehicle we plan to use for those trips is about 15 years old. Although reliable, it occasionally becomes a bit temperamental.
I don’t want to be stranded far from home while on these trips, so I found myself reaching across the front seat into the glove box for the operator’s manual to browse through recommended maintenance timelines. Where does the vehicle fall on the timeline and what should we be inspecting and replacing?
An offline inspection, along with an understanding of how the heat transfer panel moves during operation, shows that the panel and the support clash. This will cause tube wear and an eventual leak.
Normally, I would not be looking at a car’s maintenance schedule beyond visually watching when I need to change oil or replace tires. I’ll admit, that’s not the best practice. While I should be following published maintenance milestones more closely, not adhering to the inspection guidelines is a risk I’m willing to take in this scenario. I’m decently handy and can deal with most minor or routine maintenance tasks if something pops up. And should something major happen, we are fortunate to have another vehicle in our household, have family nearby to borrow a vehicle from and live in an area with multiple auto part stores and service garages.
Offline inspection shows what seems like minor wall insulation loosening. It could lead to hot spots, outer casing cracking and a personnel safety hazard. Loose insulation can foul downstream equipment, limiting heat transfer effectiveness, derating emission reduction equipment and increasing flue gas back pressure.
Investing in robust and specialized inspections not only helps prevent costly failures and unscheduled downtimes but can lead to optimization of the overall efficiency and performance of the plant. Inspections provide a comprehensive assessment of the equipment’s current condition.
But this got me thinking about equipment failure risks and consequences. While my potential vehicle woes can probably be mitigated easily, what about the large, custom-designed equipment that is subject to the cycling, high temperatures and pressures that we deal with daily in our facilities? What impact does a forced outage have? How available are repair components for the large equipment? Are items off the shelf or is custom fabrication needed? What can be done now to prevent equipment from going offline in the future?
Online and offline inspections become essential tools to identify potential issues before they escalate.
Online inspections. Similar to detecting car noises or feeling vibrations while driving, online inspections conducted while the equipment is in operation can identify immediate issues that may not be apparent while the equipment is offline. Thermal cameras can be used to detect outer casing hot — or cold — spots. Unusual vibrations, pipe hanger movement restrictions or fluid leaks may be visible. Comparing performance measurements to expected benchmarks can reveal efficiency issues.
Offline inspections. These inspections allow for a more thorough examination of both the internal and external components of the equipment. Visual is key here. Major things, like seeing something dragging underneath your vehicle, are easy to spot. It’s not as easy to identify something smaller that’s often overlooked, like a worn-out car engine belt. The same could be said for the equipment details — sometimes it’s the small and easy-to-miss ones that could lead to a major failure.
Borescope inspections. These are used to search areas that are difficult to access. Is there material loss inside the tube or deposits forming where they shouldn’t be? Is the sacrificial internal pipe liner intact, or are the support tab welds cracking and potentially causing the steel to flow downstream?
Ultrasonic testing. Testing the thickness of tubes, pipes and plates can help identify material thinning due to corrosion or erosion, which can lead to failures if left unaddressed.
OEMs can play a big role. Partnering with an OEM can enhance the effectiveness of inspections and subsequent maintenance activities. Take the inspection tasks off your personnel’s "to-do" list so they can focus their talents elsewhere. An OEM’s involvement can bring several additional benefits, including:
A close look here exposes a corner angle welded to two different liner sheets that need to move independently. There’s a good chance that welds will crack, or the angle will buckle under stress, potentially exposing insulation.
- Planning and inspection. OEMs have assembled the original equipment and can help put a plan in place to gain access to critical areas for inspections. They know what can and cannot come apart and can quickly advise on items to fix now compared to things to keep an eye on and plan to repair next time.
- Material redesign and fabrication. Based on the inspection results, OEMs can provide expert recommendations on material upgrades or redesigns to improve the equipment’s durability and performance. They can provide retrofit components that ensure compatibility with the rest of the equipment and process design.
- Specialized knowledge and expertise. OEMs have extensive experience with the equipment and are often aware of common failure points and best practices for maintenance. Their specialized knowledge can help in diagnosing complex issues during the inspections that may not be evident to general inspectors.
- Innovative solutions. Collaborating with OEMs allows plants to access the latest advancements in designs, leading to innovative solutions that improve equipment efficiency and longevity.
Online inspections of the flame length, color and shape in heat recovery steam generator duct burners can indicate problems, especially if the flames are hitting the roofs, sidewalls, or downstream tubes. The blue color here indicates excess air; a thick, yellow flame is desired.
Fresh perspectives
There are benefits to consistency in inspection teams, but new inspectors can bring new ideas. They bring diverse experiences and insights, which help identify issues that may have been previously overlooked. A fresh perspective can validate previous findings, challenge assumptions and offer insights based on similar past situations encountered elsewhere.
Consider the risks and consequences should something send a plant into an unplanned outage. Investing in robust and specialized inspections not only helps prevent costly failures and unscheduled downtimes but can lead to optimization of the overall efficiency and performance of the plant. Inspections provide a comprehensive assessment of the equipment’s current condition. The inspection results can serve as benchmarks for comparing future equipment conditions, enabling long-term discussions on life expectancy and potential retrofit options.
Deltak Inc. is a U.S.-based heat recovery steam generator and waste heat boiler designer and fabricator. Deltak Inc. supplies new and retrofit equipment worldwide and offers aftermarket services including spare parts, analysis and inspections.
For more information, visit deltak.com.
