NOx, dioxins and furans, hydrocarbons (TOC) and ammonia can be reduced with our catalytic gas cleaning systems to fulfil the global most stringent requirements. This procedure works without producing residues that must be disposed. NOx reduction: To convert the nitrogen oxides at the catalyst surface into nitrogen (N2) and water (H2O), ammonia (NH3) will be injected into the flue gas stream.
The following chemical reactions proceed in the catalyst:

4 NO + 4 NH3 + O→ catalyst → 4 N2 + 6 H2O

2 NO2 + 4 NH3 + O2 → catalyst → 3 N2 + 6 H2O

This method is referred as "Selective Catalytic Reduction" and is commonly known as "SCR - process". The great advantage of the catalytic denitrification is that apart from the conversion of nitrogen oxides also dioxins and furans are decomposed in the catalyst pores.

The operating temperature during catalytic NOx removal is limited to a certain range. When this range is not maintained, the catalyst may be deactivated. Ammonia-sulphur compounds will be formed in case of too low temperature values.

General operating values for catalytic gas cleaning systems are:

  • Amount of gas: from 15’000 to 500’000 m3/h
  • NOx raw: from 200 to 2000 mg/m3
  • NOx clean: from 20 to 200 mg/m3
  • NH3-slip: below 5 mg/m3 
  • Dioxin/furan reduction: up to 99 %
  • Reducer: e.g. Ammonia water 25 %

The essential components of a DeNOx-plant are:

  • Storage tank in which the ammonia water is stored
  • Pumps which deliver the ammonia water for injection
  • Evaporator in which the ammonia water vaporizes
  • Nozzle lances for the injection of ammonia into the flue gas
  • Gas distribution units, so that the flue gas is distributed homogeneously over the entire cross-section of the reactor
  • Catalyst layers consisting of individual catalyst modules


ELEX offers you a solution for every application. DeNOx plants can be built in countless ways - according to your specifications and requirements: a clean gas-, raw gas-, high-dust-control or as a low temperature system.

For each application, we develop the technically optimal and most economical solution. Constant optimization and further development, incorporating new technologies as well as the evaluation of measurements under a wide range of operating conditions, have brought us an immense experience. With ELEX, you choose a plant that offers unrivalled know-how.

Get in touch with us to identify the best possible solution for your situation.

Please choose a category below for references to specific applications:

Production plants in the glass industry Learn more
Iron and steel production Learn more
Production plants for cement, limestone and gypsum (kilns, mills, dryers and coolers) Learn more
Coal- and biomass-fired steam boilers Learn more
Refuse and sludge incinerators Learn more

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