NOx treatment

NOx treatment

Prossergy is a major actor in NOx treatment solutions with over a hundred
references across various applications and industries.

DeNOx SNCR

NOx treatment by SNCR (Selective Non-Catalytic Reduction) implies reducing NO and NO₂ into water and nitrogen. To get the proper reaction, the addition of a reducing agent (NH₂ molecule) and a temperature between 850 and 1050°C, is required.

The reducing agent can be urea or ammonia, reacting as follows:
CO(NH2)2 + 2 NO + ½ O2 ⇒ 2 N2 + CO2 + 2 H2O (Urea)
4NH3 + 4 NO + O2 ⇒ 4 N2 + 6 H2O (Ammonia)

For a real effective perfectly controlled reaction, the reagent must be injected into an optimal temperature zone with sufficient residence time within the equipment. It’s also necessary to minimize ammonia slip to prevent ammonium salt deposits and and possible corrosion on the equipment.

PROSSERGY SNCR process, developed over more than 20 years out of experience, is tailored to each specific installation:

  • Custom design based on the installation features.
  • Efficiency on NOx reduction up to 60-70% or more.
  • Reduced operating costs through optimized reagent and utility consumption.
  • High level of automation, thus reducing human action.
  • Very low maintenance costs.
  • Compact design.

PROSSERGY also makes optimizing and revamping existing installations.

DeNOx SCR

In SCR (Selective Catalytic Reduction) processes, the reaction is similar to SNCR but occurs at lower temperatures with addition of a catalyst, achieving higher efficiency (up to over 95%). Reagent consumption is lower, and ammonia slip is minimal.

SCR catalysts typically operate between 180 and 450°C. They consist of a support, usually ceramic (sometimes metal), impregnated with an active phase. The support can take various forms: monolith, plates, or pellets.

These catalysts are sensitive to certain poisons in the flue gas, requiring expertise from professionals to achieve effective and reliable implementation.

Integrating SCR into the flue gas treatment and inside the unit thermal loop is a key issue to get optimal environmental performance, reliability, and energy efficiency.

Advantages of SCR:

  • Very high reduction efficiency with minimal ammonia slip.
  • Low reagent consumption.
  • Easy scalability for lower emission limit values.
  • Potential to combine SCR with dioxin/furan reduction.

Hybride DeNOx

PROSSERGY’s Hybrid DeNOx solution combines the best of both SNCR and SCR processes:

  • Simplicity and low cost of SNCR.
  • Efficiency of SCR.

Thanks to a strong expertise PROSSERGY manages the enhancement of high-performance SNCR with a compact SCR catalyst easily installed downstream of the filtration. Coupled with advanced control systems optimizing reagent injection based on furnace conditions, the HyDNX hybrid solution offers:

  • Optimized investment and operating costs.
  • Elimination of reheating and regeneration burners.
  • Easier integration into existing units.
  • Increased energy efficiency through the addition of an economizer downstream of the catalyst.