I-NOx® Integrated NOx Reduction System
High Performance NOx Reduction at Low Capital Cost
- Lower Capital Cost vs. Conventional SCR
- Minimizes SO2 to SO3 Conversion
- Combines Commercially Proven Technologies
- Proven Mercury Oxidation of 90% +
Fuel Tech’s I-NOx® Integrated NOx Reduction System combines proven technologies for cost-effective NOx control from the point of combustion to the stack. These combined technologies may be applied as a retrofit solution for existing units or may be new generating units, capable of NOx reduction exceeding 80%.
The front end of an I-NOx system utilizes Fuel Tech’s proven combustion technologies including: Low NOx Burners (LNB), burner modifications, and over-fire air (OFA) systems. These combustion solutions are then built upon using our post combustion NOx control products which include urea based Selective Non-Catalytic Reduction (SNCR) along with urea- and ammonia-based Selective Catalytic Reduction (SCR) systems.
The distinguishing features that sets the I-NOx technology apart is our commercial experience and state-of-the-art design capabilities that allow us to understand the working relationships of the combined NOx reduction technologies. These capabilities also allow us to evaluate each application and tailor a solution that maximizes the contribution of each technology in our suite of offerings without pushing any one process to the point that it impacts boiler operation or negatively impacts another NOx reduction process downstream.
The I-NOx system offers significant lower capital costs than traditional SCRs and provides the option of a staged capital investment.
Components of an I-NOX System
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. Fuel Tech has many tools to provide the most efficient design for our ASCR™ Advanced SCR 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.
The ASCR technology component of an I-NOx system incorporates a high performance SCR reactor where space permits. By utilizing an integrated technology approach, 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."
The scope of supply for Fuel Tech's I-NOx systems include design, engineering, procurement, delivery, and startup of the following:
- Combustion Modifications in the Form of LNB and OFA
- NOxOUT® and HERT™ SNCR Systems
- Rich Reagent Injection Systems
- ASCR™ Advanced SCR Systems and Components
- Modeling and Process Design with Performance Guarantees
- Static Mixer
- Large Particle Ash Screen (LPA)
- GSG™ Graduated Straightening Grid
- Ammonia Injection Grid (AIG)
- Catalyst Specification and Supply
- SCR Reactor Design and Supply
- System Startup, Optimization, and Training Services
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 integrated I-NOx systems may be applied to retrofit and new boiler applications, and our experience includes installation of systems on more than 800 units, SCR design and consulting support on more than 50,000 MWs, and over 20,000 MWs of AIG Tunings.
Fuel Tech’s I-NOx system is a combination of technologies that provide cost effective NOx reduction and flexibility in meeting rapidly changing regulatory and public policy drivers. I-NOx systems can be implemented in stages over time, providing financial advantages of both lower total installed capital costs and the ability to stage capital expenditures.
The NOxOUT CASCADE® process is a specific type of I-NOx system using a special urea-based, in-furnace SNCR process with a compact back-end catalyst (SCR) module that is much smaller and less capital intensive than conventional SCR designs. The chemical reagent usage with NOxOUT CASCADE is improved over conventional SNCR.
On a stand-alone basis, the NOxOUT® process is designed to operate at higher than optimum furnace temperatures to minimize ammonia NH3 slip to 2 to 10ppmv. This is especially important for electric utility units where the NH3 can combine with SO3 emissions to form ammonium bisulfate (ABS), which can affect a boiler’s air pre-heater.If the SNCR process is designed with urea injection to take place in the optimum range, NOx reduction may be dramatically improved, but NH3 slip will also increase. Fuel Tech can take advantage of this condition by installing a compact SCR catalyst layer in an expanded duct section that can use this excess NH3 for further NOx reduction. Since the SCR catalyst need only remove a portion of the NOx, it is significantly smaller and less capital intensive than a full SCR system. NOxOUT CASCADE systems are installed on six 600 MW units in the People’s Republic of China, and on a 110 MW unit in the northeastern U.S.