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ULTRA® Systems

Fuel Tech Air Pollution Control TechnologiesULTRA® Systems

On-Site Ammonia Generation

Fuel Tech is the world’s leading supplier of NOX reduction and urea reagent technologies. The ULTRA® conversion process and systems are designed by experienced in-house engineering personnel and backed with significant commercial experience. The systems are manufactured to ensure quality and longevity while providing a reliable, safe, and easy to use system for the on-site generation of ammonia.

How It Works: Simple Process for Urea Decomposition

The ULTRA process generates low-pressure, dilute ammonia for SCR systems and flue gas conditioning applications by thermally decomposing urea. The diluted ammonia is fed through the ammonia injection grid (AIG) to the SCR. The ULTRA process controls ammonia generation by metering urea into a decomposition chamber. The generation rate responds rapidly based on urea flow rate. The ULTRA system is simple, consisting of a blower, heat source, decomposition chamber, urea storage, urea metering and process controls.

ULTRA process diagram - safe ammonia generation


  • Safe & simple urea reagent
  • Eliminates the risk of hazardous chemical handling
  • Low-pressure operation
  • Capacities available for small and large SCR applications
  • Integrated systems for retrofit or greenfield applications
  • Backed by 57,000 MW experience with over 230 systems installed worldwide

System Options

The ULTRA system can be customized for each application. In addition to natural gas, potential heat sources include electric heaters for small systems, and fuel oil or propane for larger systems. Where energy efficiency is critical, we can use pre-heated combustion air directly or in conjunction with a heat exchanger to preheat ambient air. Aqueous urea can be delivered to the site or created on-site using granular or concentrated urea solutions by adding condensate or demineralized water. It is important that quality requirements of the water being used to create the urea solution are followed to ensure no negative impacts on the SCR catalyst performance.

ULTRA 5® & ULTRA 1™ Process

The ULTRA 5® and ULTRA™ 1 systems are modular and compact for reagent demand rates of 5 lb/hr or less. The ULTRA 1 system consists of a single skid (4’x 8’ footprint) containing both the control module and decomposition chamber. For the ULTRA 5 systems, the chamber is typically separate from the control module. These compact systems offer a cost effective, simple solution for providing on–site ammonia generation of 1 to 5 lbs per hour. From package boilers to combined heat and power (CHP) facilities, ULTRA may be applied to new and retrofit SCR systems. Many small SCR applications may be located indoors. Anhydrous ammonia in bottles or 19% aqueous ammonia systems are often used for the SCR reagent feed. The storage of ammonia in confined spaces creates safety concerns of noxious fumes and fire hazards should leaks occur.

ULTRA Decomp Chamber

ULTRA-EX™ Utilizes Hot Gas Turbine Exhaust as a Heat Source

High temperature exhaust gas from the combustion turbine is extracted from the HRSG, directed to the Decomposition Chamber, and returned to the flue gas path. The extracted flue gas, which is drawn from the HRSG using a high temperature blower, thermally decomposes the concentrated urea solution that is injected and distributed in the ULTRA chamber. The temperature of the flue gas typically is greater than 800°F and it is particulate free. As with our other ULTRA systems, the urea injection rate is varied in response to ammonia demand changes, but the total flow rate of the NH3/air mixture remains relatively steady.


The ULTRA process simplifies SCR operation using safe urea reagent for the on-site generation of ammonia, with feed rates ranging from 1 to 1,300 lb/hr.



ULTRA-QS™ Quick Start Process for SCR Operation Within Minutes

ULTRA-QS™ has the ability to rapidly respond to changes in ammonia demand rate for combustion units using SCR technology to control NOemissions. The system can be injecting urea and producing ammonia for the SCR within 10 minutes of receiving the operating permissive. This duration is acceptable for most GT/HRSG applications to avoid thermal stress on SCR and HRSG tubes from rapid temperature increase. The typical power cost of operating ULTRA-QS in standby mode is only $20 to $25 per day.



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Ultra Related Literature

SCR Applications

250+ Installation Worldwide 

  • Combined Heat and Power Plants
  • GT and HRSG applications
  • Industrial package boilers (steam and hot water)
  • Distributed generation
  • Petrochemical facilities
  • Airports
  • Hospitals, Universities, Colleges, and other campus environments
  • Peaking plants
  • Coal-fired boilers
  • Stationary engines

ESP Applications

  • Ammonia generation for flue gas conditioning (FGC)