Replacement NSCR Catalysts
Many Industrial Air Pollution Control applications involve the removal of NOx compounds as part of the end users air permit. Depending on the constituents in the exhaust stream, two types of catalyst can be used, SCR or NSCR.
Selective Catalytic Oxidation(SCR) uses ammonia or urea as a reductant in conjunction with a specialized SCR catalyst, typically V/Ti/W based. Some zeolite catalysts are also used for certain applications where it is a good fit.
Non-Selective Catalytic Reduction(NSCR) typically uses a precious metal based catalyst, in conjunction with Carbon Monoxide (CO), Hydrogen (H2) or Methane (CH4) as the reductant. NSCR reactions require that the oxygen content in the exhaust gas be very low, on the order of < 1% O2. An example of NSCR is with engine emission control, such as automobile catalysts. Tuning the engine to have a stoichiometric balance of CO, Hydrocarbon, and NOx compounds, allows a “3-way” catalyst, typically a mixture of Pt/Pd/Rh, to simultaneously remove all three target compounds, NOx, CO and the HC.
Another example where NSCR is very effective is in Nitric Acid tail gas applications. Here, in some high pressure, high temperature applications, the O2 content and NOx ppm levels are just right for a precious metal based NSCR catalyst.
Contact Applied Catalysts about your NOx control application.