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Urea SNCR Systems - NOxOUT® and HERT™

Fuel Tech Air Pollution Control TechnologiesUrea SNCR Systems - NOXOUT® and HERT™


Fuel Tech SNCR diagram 300The NOXOUT® SNCR Process is a urea-based Selective Non-Catalytic Reduction (SNCR) process for reduction of oxides of nitrogen (NOX) from stationary combustion sources. The process requires precisely engineered injection of stabilized urea liquor into combustion flue gas temperatures as high as 2500° F.

Fuel Tech customizes the design and injection strategy for each application since most NOX reduction occurs in a temperature range between 1650° F - 2100° F. As shown in the diagram, the injection is typically multi-level and controlled automatically to adjust urea injection in response to boiler load changes and changing furnace conditions. 




  • 25% - 50% NOX Reduction
  • Average NOoutlet emissions for large systems less than 0.16 lb/MMBtu


Fuel Tech Experience: Urea-based Selective Non-Catalytic Reduction (SNCR)

  • More than 50 systems installed on units greater than 400MW, totaling more than 30,000MW
  • Over 630 Installations Worldwide
  • Bubbling Fluidized Beds


HERT™ High Energy Reagent Technology™ SNCR System

Basin SNCR InjectorsThe HERT™ High Energy Reagent Technology™ system uses a high energy injection strategy to inject urea into the furnace. Depending on the specifics of each application, the injection can be through the over-fire air or by using a dedicated air stream provided by a small, separate blower skid. The HERT™ systems have met NOX reductions guarantees on commercial installations while minimizing ammonia slip with this patented injection process. 

The SNCR systems provided by Fuel Tech may include NOxOUT injectors along with HERT system injection technology, using the same urea storage, handling and control components. Fuel Tech's SNCR applications rely heavily on the use of Computational Fluid Dynamics (CFD) models and Chemical Kinetics Modeling and their resulting visualization utilizing proprietary software. Our NOXOUT SNCR technology is sufficiently flexible to apply to a variety of commercial and process combustion units, as detailed below. 

SNCR Technologies Fuel Tech


  • Coal
  • Lignite
  • Oil
  • Gas
  • Municipal Solid Waste
    • Sludge
    • Wood
    • Biomass
    • Refinery/CO Gas

Process Combustion

  • Cement Kilns
  • Glass Furnaces
  • Ethylene Furnaces
  • Calciners
  • Coke Ovens
  • Lime Kilns

Commercial Combustion Units

  • Tangentially-Fired Utility Boilers
  • Cyclone-Fired Utility Boilers
  • Wall-Fired Utility Boilers (wet & dry)
  • Refinery Crude Heaters and CO Boilers
  • Sludge Combustors
  • Industrial Power Boilers
  • Municipal Waste Combustors
  • Incinerators
  • Circulating Fluidized Bed Boilers
  • Stoker-Fired Boilers Burning Wood and Coal
  • Package Boilers


Meets BACT Requirements

From a compliance standpoint, the NOXOUT process has been used to satisfy Best Available Control Technology (BACT) requirements for Municipal Solid Waste combustors, coal-fired Independent Power Producer (IPP) units, and fluidized bed boilers. The SNCR process has been used to comply with Reasonably Available Control Technology (RACT) requirements in ozone non-attainment areas and Administrative Compliance Orders in specific locales.

A primary feature of the NOXOUT and HERT processes is the ease of combination with other NOX reduction technologies. Combinations that have been retrofit with the NOXOUT process are low NOX burners, over-fire air, combustion tempering, neural network controls, and gas reburn. Fuel Tech’s patented ASCR™ Advanced SCR process combines a variety of technologies to provide up to 80+% NOX reductions at a fraction of the cost of conventional SCR systems.