BASF NOXCAT™ AD Catalyst: The Preferred Choice in Ammonia (NH3) Emissions Abatement BASF NOXCAT™ AD Catalyst features high selectivity for ammonia decomposition into nitrogen and water rather than ammonia oxidation into nitrogen oxide (NOX). Additionally, this patented catalyst technology provides oxidation of carbon monoxide (CO) and certain volatile organic compounds (VOCs).
NH3 Slip Reduction Another application is in SCR systems, where excess ammonia reactant must be controlled. Installing BASF NOXCAT™ AD Catalyst at the exit of a Selective Catalytic Reduction (SCR) catalyst bed controls NH3 slip, which in turn: n
n
Enhances operational control of an SCR system by curbing peak NH3 slip emissions associated with reactant maldistribution or overdosing in response to sudden and dramatic changes in NOX emissions Extends SCR catalyst operating life by controlling elevated NH3 slip levels that characterize aged catalyst
Another benefit from controlling the ammonia slip, especially for the power generation industry, is the potential reduction of ammonium bisulfate, which adheres to and fouls surfaces of air preheaters and boiler tubes, thus decreasing their efficiency. Proven Success BASF NOXCAT AD Catalyst has a proven track record of success. Two examples are: ™
Controlled Ammonia Slip Emissions in a Challenging SCR System A batch production site, with exhaust gas recirculation, used two SCR systems in series to control NOX emissions in their primary exhaust and recirculating gas flows. The ammonia injection scheme was challenged by this complex emissions abatement system design and often over-injected NH3 due to uncontrollable delays in the response time of the system. To stabilize the control of the emissions abatement system, BASF NOXCAT™ AD Catalyst was installed downstream of the second SCR catalyst bed as a last means for controlling NH3 slip emissions. This solution proved itself to be robust,
Preferred Solution for NH3 Emissions Abatement with Minimal Change in NOX Emissions In a batch production unit, two product formulations were produced. The same emission control system had to cope with the two formulations, although they generated two distinct emission profiles: Formulation A produced a NOX emission greater than its NH3 emission; Formulation B produced a NOX emission much less than its NH3 emission. Although an SCR catalyst with supplemental NH3 injection was suitable for Formulation A, it was ineffective for Formulation B, since a significant amount of the NH3 emission remained unreacted through the SCR catalyst due to a lack of NOX. A standard oxidation catalyst was installed, but soon proved inadequate as it converted too much of the NH3 to NOX. Once BASF NOXCAT™ AD Catalyst replaced the standard oxidation catalyst, the emissions abatement system reliably controlled both NOX and NH3 emissions for all batch calcination formulations, having reduced NH3 emissions by over 98% to less than 10 mg/Nm3 with no net impact on NOX emissions and no extra pressure drop penalty from the original design. Formulation A
Formulation A or Formulation B
Batch Calcination Oven
NOx > NH3 or Formulation B NOx < NH3
Temperature: 280–400°C
NH3 Reductant Injection “On” for Formulation A “Off” for Formulation B
For more information on BASF NOXCAT™ AD Catalyst, please contact ammonia-destruction@basf.com.
STACK
In the electronic industry (such as production of circuit boards and semiconductors), wastewater treatment and chemical industry, for instance, the catalyst can be an alternative to scrubbers.
NOxCAT™ AD Catalyst
BASF NOXCAT™ AD Catalyst can abate up to 1.5 vol.% NH3 emissions without the need for supplemental dilution air to control the exothermic reaction. The technology works over a wide range of operating temperatures (300–500°C) with minimal NOX formation as a reaction by-product.
as BASF NOXCAT™ AD Catalyst enabled NH3 slip emissions control independent of the NOX concentration in the exhaust gas. Throughout the batch production cycle, the NH3 slip in the stack was controlled consistently to less than 10 mg/Nm3, which was equivalent to as much as 99% NH3 conversion, with no net impact on stack NOX emissions.
SCR
Control NH3 Emissions in Industrial Processes