High-Temperature Urea Dilution & Vaporization Skids
In SCR and SNCR applications, these skids act as the critical "engine" that transports vaporized reagent into the flue gas duct. Unlike ammonia, urea requires a significantly higher heat profile for successful decomposition. RM Technologies builds these systems to ensure a stable, high-temperature air stream that protects your catalyst and ensures uniform NH₃ distribution.
System Components & Core Technology
- High-Static Blowers: Equipped with centrifugal or regenerative blowers to provide a constant, high-velocity "carrier air" stream.
- High-Capacity Electric Heaters: Engineered to heat carrier air to temperatures often exceeding 600°F to 800°F prior to urea injection.
- VFD-Driven Motors: Variable Frequency Drives precisely match air velocity with fluctuating boiler flue gas loads to prevent nozzle plugging and scaling.
The Chemistry of Decomposition
To convert liquid urea into reactive ammonia gas (NH₃) before it hits the catalyst, the reagent must undergo thermolysis and hydrolysis. If temperatures are too low, urea fails to decompose, instead forming solid cyanuric acid and "popcorn" urea deposits that can destroy a catalyst.
The RM Technologies Engineering Triple-Layer
We utilize three specific strategies to keep your system in the Optimum Performance zone:
- The 600°F Interlock: PLC logic includes a "Permissive to Inject" safety. Urea dosing pumps remain inactive until the heater confirms a downstream temperature of 550°F – 600°F, preventing "cold-start" scaling.
- Residence Time Optimization: We size Vaporization Chambers (the "Mixing Pipe") to ensure urea droplets have a minimum "bake time" of 0.5 to 1.0 seconds before entering the main flue gas duct.
- Load-Based Tuning: Using VFDs and SCR Power Controllers, the skid automatically increases carrier air temperature when boiler loads (and flue gas temperatures) drop, maintaining a consistent decomposition environment.
Operator Strategy: The "Clean-Out" Burn
If minor scaling is suspected, operators can perform a "Clean-Out" procedure:
- Temporarily increase the dilution air heater setpoint by 50°F.
- Maintain for 2 hours while the boiler is at full load.
- This process sublimates minor deposits before they harden into permanent obstructions.
Don't let crystallization, pump failures,
Or NOx compliance issues shut down your operations. In urea-based SCR systems, even a minor calibration error can lead to costly unscheduled downtime and environmental fines. Whether you are dealing with "plugging" in the injection nozzles or erratic dosing logic, you need a systematic approach to identify the root cause fast. Download our Urea Dosing System Troubleshooting Guide, built on 30+ years of industrial ammonia and urea expertise, and get your system back to peak efficiency today.