It was in 1999 with the SNCF (French National Train Company) that SEV-Services developed its first gas scrubber system.
At that time the system consisted of a DOC catalyst, an SCR and a venturi scrubber.


Based on his experience of coatings applied to metal catalysts SEV-Services has developed its own system for reducing nitrogen oxides (Nox): SEV-NOX.

Based on SCR technology, the SEV-NOX is an active system using the injection of a reducing agent (ammonia or urea) to produce nitrogen and water.

Managed by an electronic control unit, homogeneous diffusion of urea is ensured through specific rods for injection soundly positioned before the catalytic reactor.

The ratio of abatement can reach up to 95%. (See Diagram)

Thus, the main pollutants produced by diesel engines (CO, HC, PAH, NOx, Particulates) or gas (CH2O) can be significantly reduced to meet the thresholds enforced by European legislation.

Aftertreatment solutions

Our various pollution control systems are based on the following technologies:

  • DOC (passive system): Catalytic oxidation of hydrocarbons (HC) and carbon monoxide (CO)
  • FAP (passive system) particulate filter with catalytic combustion of soot
  • SCR (Active System): Selective Catalytic Reduction of NOx
  • Ammonia Slip (passive system): Removal of ammonia odors


Then other systems have been performed,with customers like EUROTUNNEL and recently TSO.
SEV-Services has developed its own tools for calculating and sizing.
Standard values are established for a reference diagnosis.
Depending on the specifications of your engine (Power; Back pressure; Fuel, Flow rate) and targets to achieve, SEV-Services can take care:

  • Diagnosis
  • Engineering
  • Manufacturing
  • Implementation
  • Start-up
  • Final inspection

The SEV-NOX package is based on a standard and proven technology (DOC + DeNoxSCR + FAP).
On top SEV-Services has the ability to integrate the system into the environmental engine.