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ASCR® Advanced SCR

Fuel Tech Air Pollution ControlASCR® Advanced SCR

Installing Catalyst Fuel TechFuel Tech’s ASCR® Advanced SCR process maximizes performance and minimizes cost and space requirements when needed. Where high level NOx reduction are required, ASCR can be applied to full scale reactor designs to maximize performance.

SCR process design is the most critical step to successful SCR performance. Maximizing SCR performance and minimizing its impact on plant operations requires a thorough understanding of each application. For each project, Fuel Tech reviews potential fuels and fuel blends and the expected operating conditions and then utilizes its experience and design expertise to provide the best possible SCR design.

Process Performance from Comprehensive Design

Fuel Tech has many tools to provide the most efficient design for our ASCR systems. Our experimental model studies combined with Computational Fluid Dynamics (CFD) modeling provide insight into the flue gas parameters and flow conditions to develop the optimum duct configuration for the SCR. Fuel Tech works with industry leading catalyst suppliers to determine the appropriate catalyst type and formulation for any given application.

Flow correction devices such as turning vanes, large particle ash (LPA) screens, static mixers, and the GSG™ Graduated Straightening Grid are used to implement an ASCR that meets its performance goals. These important design steps help ensure trouble-free ASCR operation and maximize catalyst life.

The ammonia injection grid (AIG) is used to feed aqueous or anhydrous ammonia to the catalyst to ensure proper coverage to react with NOwithin the catalyst. Proper mixing of flue gas constituents and temperatures along with proper flow and velocity profiles to maximize NOreduction and to minimize ammonia slip emissions.

Performance and Fuel Tech Expertise

  • 90+% NOx Reduction

  • Optimized SCR design

  • 55,000+ MW experience in SCR process design

  • 20,000+ MW of SCR Optimization

  • More than 30 systems in operation

The ASCR System Offers High Performance and Flexibility for Compact or Full-scale Reactor Applications


ASCR model - Fuel TechThe ASCR technology incorporates a high performance SCR reactor where space permits. By utilizing higher flue gas velocities, the catalyst quantity, weight, and space requirements can be minimized, potentially leading to the elimination of new foundations and the need to install new “steel to grade.” This allows ASCR to be applied where multiple catalyst layers will not fit, or are not required to meet NOx reduction targets. This same optimized SCR design approach can be applied where full scale SCR performance is required. 

The ASCR system is designed to minimize the rate of SO2 to SO3 conversion which is a precursor to ammonium sulfate/bisulfate formation in the air preheater. This low conversion rate allows for a broader unit operating range and fuel flexibility.

Fuel Tech’s extensive experience base and financial status allow us to offer single source responsibility. System installation and installation management services are also available to meet customer needs. Our experience includes more than 30 SCR system installations and SCR design and consulting support covering more than 50,000 MWs, along with providing SCR services on over 20,000 MWs. 

The Scope of Supply for Fuel Tech's ASCR Systems Include Design, Engineering, Procurement, Delivery, and Startup of the Following:


  • Modeling and Process Design with Performance Guarantees
  • SCR Reactor Design and Supply
  • Catalyst Specification and Supply
  • Static Mixer
  • LPA Screen
  • GSG™ Graduated Straightening Grid
  • System Startup, Optimization and Training Services