Reduction and Oxidation Catalysts - Overview

NOx + NH3 N2 + H2O

The most effective method of post-combustion control of NOx is Selective Catalytic Reduction (SCR). This technology routinely removes up to 85% of NOx and can be pushed to a higher removal efficiency. The gas velocity is reduced in an expanded section of ductwork, ammonia carefully metered into the gas stream and balanced to match the distribution of NOx across the duct. The gas stream then passes across a special catalyst designed to cause a reaction between the NOx and ammonia, resulting in their conversion to nitrogen and water vapor.

CO Reduction

Because high NOx reduction requirements are often accompanied by CO abatement regulations, PPC offers optional CO catalyst combined into the SCR system. CO reduction catalyst can be integrated into the SCR with very little space requirement.

Combination systems

PPC provides SCR and CO catalyst beds that are integrated into the dry electrostatic precipitator (ESP) design. This provides several advantages:

  • Separate support steel is often not required.
  • The hot side electrostatic precipitator (ESP) removes up to 95% of the particulate matter allowing the same reduction with less catalyst and a longer catalyst life.
  • The ESP removes metallic salts that can poison the catalyst.
  • The precipitator conditions flow and distribution of the flue gas for the NOx and CO catalyst chamber.
  • Single point responsibility for the system.
  • Economical design that incorporates particulate control in combination with CO and NOx control.