Trivision Technology Taiwan Co., Ltd

Products SCR DeNOx System

NO_x is normally formed from the process of steel milling, glass melting, boiler, incinerator, power plant and thermal oxidizer etc. due to high process temperature, or by chemical reaction, such as manufacture of nitric acid, nitrocellulose, and explosive etc.

Nitrogen oxide (NO) is oxidized by oxygen to nitrogen dioxide (NO₂), which will be affecting visibility of human eyes and causing respiratory diseases and lung cancer.

Selective Catalytic Reduction (SCR) is a means of converting nitrogen oxides (NO₂), which is also referred as NOx with the aid of a catalyst into diatomic nitrogen (N₂), and water (H₂O).
A reductant, typically anhydrous ammonia, or urea solution is added into stream of flue or exhaust gas, which is adsorbed by the surface of SCR catalyst. As the reaction drives toward completion, nitrogen, N₂ and water, H₂O is produced.

NOx reduction reaction takes place as flue gases pass through SCR catalyst reactor. Before entering SCR reactor, ammonia, or urea solution is injected to and mixed with the flue gases.
The chemical equations for a stoichiometric reaction using either anhydrous or aqueous ammonia for a selective catalytic reduction process are:

4NO + 4NH₃ + O₂ → 4N₂ + 6H₂O
2NO₂ + 4NH₃ + O₂ → 3N₂ + 6H₂O
NO + NO₂ + 2HN₃ → 2N₂ + 3H₂O

4NO + 4NH₃ + O₂ → 4N₂ + 6H₂O
2NO₂ + 4NH₃ + O₂ → 3N₂ + 6H₂O
NO + NO₂ + 2HN₃ → 2N₂ + 3H₂O

The reaction for urea instead of either anhydrous or aqueous ammonia is:

4NO + 2(NH₂)2CO + O₂ → 4N₂ + 4H₂O + 2CO₂

4NO + 2(NH₂)2CO + O₂ → 4N₂ + 4H₂O + 2CO₂

The use of SCR system is now vital in meeting Euro VI diesel emissions standards for heavy duty diesel vehicles, NRMM (non-road mobile machinery), and generator sets. In many cases, reduction of emissions of NOx has been requested by upwards of 95%.
Typical design of SCR system for Generator Sets.

Global Strategic Partner of SCR :
H+H Engineering & Service GmbH
www.huhes.de