Benefits:

• Provides 30%-60% NOx reductions at low cost.
• No need to replace current burners.
• Ideal technology for ozone season.
• Easy to retrofit with minimal downtime.
• No by-products for disposal.
• Low energy consumption (typically 20-40kW).
• Controls ammonia slip.
• Application of NOx control burner add-ons and Combustion Tempering to SNCR reduces annual costs of such systems by 65%.

How it works:
The reagent (urea) is injected into the furnace flue gas in an appropriate temperature window. NOx and the reagent then react to form harmless nitrogen, water, and a small amount of CO. This process takes place only in a narrow 390°F (200°C) temperature range, below which NH3 (ammonia) is formed and above which NOx emission levels actually increase.

The optimum temperature window for efficient SNCR operation typically occurs between 1,620°-2,010°F (900°-1,100°C), somewhere in the steam generator and connective heat-transfer areas. The longer the reagent is at optimum temperature, the higher the NOx reduction.

The reagent injection systems must be able to place the reagent where it is most effective, as NOx distribution varies within the cross section. An optimized NOxOUT® injection system requires multiple injection control points to maintain proper distribution ratios and minimize ammonia slip.

Using urea as the reagent minimizes the chance of air heater fouling and plugging when unreacted ammonia combines with SO3 to form ammonium bisulphate. Also, urea is not a hazardous chemical.