De-NOx systems

Nitrogen oxides, more commonly called NOx, is the generic term for a group of highly reactive gases, all of which contain nitrogen and oxygen in varying amounts.

Thermal NOx
Thermal NOx are formed when fuel is burned at high temperatures, as in a combustion process. The primary sources of NOx are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels.

Chemical NOx
Chemical NOx are formed when compounds with Nitrogen, are thermal oxidized or burned at high temperature.

The reasons for concern about NOx emissions, is that they have proved to cause respiratory trouble, and to contribute to the formation of acid rain and to global warming.

With the Göteborg Protocol and the new EU legislation (2001/81/CE), industrial companies are required to reduce and control NOx emissions.

Various systems exist to achieve such goals: low-NOx burners to avoid creating NOx, or systems for abatement of Nitrogen Oxides, also known as De-NOx systems. These are based on ammonia or urea solution treatments. Two systems exist: Selective Catalytic Reduction (SCR De-NOx), or Selective Non-Catalytic Reduction (SNCR De-NOx).