Babcock & Wilcox B&W SCR at a glance
The Dovient library currently covers 3 published troubleshooting guides for the Babcock & Wilcox B&W SCR, with 21 individual procedure steps distilled from OEM manuals and field experience. On average, a fix on this machine runs 7 steps and roughly 1.5 hrs on tools. Complexity is classified as expert-only, most procedures here involve safety-critical steps, specialised tooling, or OEM-only spares, and should not be attempted without proper training.
Failure modes to watch for
Every guide in the Babcock & Wilcox B&W SCR library lists the candidate root causes its procedure rules out. These are the distinct failure modes we've documented so far, a useful starting point if you don't yet know which specific alarm or symptom you're chasing.
Fly-ash accumulation on catalyst leading edges blocking flow channels
Soot blower failure or reduced steam supply leaving lanes un-cleaned
Popcorn ash bridging across catalyst cell openings
AIG (ammonia injection grid) ammonium bisulfate deposition at low load
AIG flow-control valve positioner fault or instrument air supply failure
Vaporizer heater element failure causing liquid ammonia carry-over
Plugged AIG nozzle(s) from ammonium bisulfate deposits
Loss of anhydrous or aqueous ammonia supply (tank low, pump off, block valve closed)
Tools you'll need most
These tools are referenced most often across the Babcock & Wilcox B&W SCR troubleshooting guides. If you service this equipment regularly, keep them on the cart.
Sources we cite for this machine
Every procedure on Dovient is cross-checked against published sources. These are the references cited most often in the Babcock & Wilcox B&W SCR guides.
- cited 3×
Babcock & Wilcox B&W SCR SCR / Emission Control general technical documentation
Babcock & Wilcox
Every published guide for this machine
How to diagnose ammonia injection malfunction on a Babcock and Wilcox B&W SCR
Zero or erratic AIG flow almost always means a stuck control valve, plugged nozzle, or cold vaporizer. Verify vaporizer temperature, check valve positioner output, and inspect the injection grid nozzles.
How to diagnose catalyst deactivation and declining NOx efficiency on a Babcock and Wilcox B&W SCR
Gradual NOx efficiency loss that requires increasing ammonia to compensate is a sign of catalyst deactivation. Pull a catalyst sample for activity testing and check for arsenic or alkali poisoning.
How to clear catalyst plugging and high backpressure on a Babcock and Wilcox B&W SCR
Rising backpressure on an SCR catalyst bed is almost always ash or soot accumulation. Trigger soot-blowing, inspect inlet baffles, and schedule a catalyst wash if the differential pressure stays high.
Frequently asked questions
What are the most common Babcock & Wilcox B&W SCR problems?
The most frequently reported issues on the Babcock & Wilcox B&W SCR include how to diagnose ammonia injection malfunction on a babcock and wilcox b&w scr, how to diagnose catalyst deactivation and declining nox efficiency on a babcock and wilcox b&w scr, how to clear catalyst plugging and high backpressure on a babcock and wilcox b&w scr. Each has a step-by-step troubleshooting guide on this page.
How long does a typical Babcock & Wilcox B&W SCR repair take?
Repair time depends on the failure mode. Routine adjustments typically take 30-90 minutes; component replacements run 2-4 hours; major overhauls can take a full shift or more. The procedures linked above list estimated time per problem.
Can these procedures be done by an in-house technician?
Most procedures on this page are designed for a qualified in-house maintenance technician with the listed tools and parts. Procedures requiring OEM-only access (firmware updates, factory calibration) are flagged in the safety warnings.
Are these guides verified against OEM documentation?
Every procedure cites the source manuals, service bulletins, or published references it draws from. The Babcock & Wilcox B&W SCR guides cross-check against 1 source(s) cited above.
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