During periodic shutdowns of the boiler unit, tube failures can occur. Quite often they are related to dew point corrosion, an insidious condition that can penetrate up to 0.50 of steel per year. Thin walled tubes that normally last 10 years can become badly pitted during shutdown, and replacement tubing becomes an unanticipated expense.
Existing Fleet Materials AnalysisMaterial failures in boiler, steam turbine, and balance-of-plant componentry accounted for 82% of fleet forced outage hours between 2013 and 2017 Largest cause of forced outages:Boiler tube leaks (across the fleet and separate size classifications) Followed by:Turbines and Balance-of-Plant Systems Cause of most boiler tube leaks:Waterwall boiler tubes
After 5 years in service a stay bar at the rear end of the boiler failed catastrophically. Upon closer inspection cracks were detected on most of the stay bar joints on the rear end side. Figure 1:Schematic of typical stoker fired fire tube boiler. An investigation was requested to determine the root cause for failure of the stay bar.
How to Destroy a Boiler -- Part 1Boilers rely on the water to protect the steel boiler tubes from the temperatures in the furnace which greatly exceed the melting point of the tube material. A buildup of deposits inside the tubes will produce an insulating layer which inhibits the ability of the water to remove the heat from the tube.
Low Water Content Boilers:The Safest Boiler Design Boiler Failures. With conventional boiler systems, a boiler failure comes with a certain amount of fear because it can be very dangerous. Conventional fire tube boilers typically operate with a large volume of water that acts basically as a heat shield for the flame to prevent the metal inside the boiler from melting.
failures in boiler tube nipples at headers are caus- ed by high temperature creep. Such failures, occur- ring in superheater and reheater tube connectors are primarily due to operation above the specified component design conditions for extended periods of time.
Tube Failures in Waste Heat Boilers:Case Histories NACE Waste Heat Boilers (WHB) generate steam while cooling a process fluid. Depending on process and steam system considerations, varied boiler designs and pressures are utilized. Some designs are susceptible to waterside corrosion problems and tube failures may be prevalent.
picture of water tube boiler Industrial Boiler SupplierFire-tube boiler Wikipedia, the free encyclopedia Horizontal return tubular boiler (HRT) has a horizontal cylindrical shell, containing several horizontal flue tubes, with the fire located directly below the boilers Update:Benchmarking Boiler Tube Failures Boiler tube failures continue to be the leading cause of downtime for steam
The visual appearance of a failed boiler or HRSG tube provides valuable information regarding the mechanism of failure. Determining the failure mechanism is the first step of the failure reduction/elimination process. The process includes the following steps:Determine Failure Mechanism; Find Root Cause of the Failures; Determine the extent of the damage