Jun 22, 2011

Proventia launches DEF Mixing Unit for eliminating urea deposits in exhaust pipes when using SCR technology

Proventia  has developed a DEF Mixing Unit (patent pending) for eliminating urea deposits in exhaust pipelines when using SCR technology in off-road machines. When SCR process uses DEF, it can cause urea deposits in exhaust pipes, especially in off-road applications using airless DEF injectors.  Larger DEF spray droplets might lead to wall wetting and film formation on exhaust pipe inner surfaces, causing deposits when the local temperatures are low.

Urea deposit problems have become frequent and critical, considering that Stage 3B/ Tier 4 interim regulations require cold and hot NRTC cycles. Proventia’s  DEF Mixing Unit keeps pipelines clean by evenly distributing  NH3 (gamma→0.95)  in the shortest possible pipe length and avoiding this way the wall wetting and film formation. 

The technology is also suitable for Tier 4 final exhaust systems, where NOx reduction target is →95%. Proventia DEF Mixing Unit helps water evaporation from DEF and ensures optimal reactions with Ammonia with no unwanted side effects.  Proventia DEF Mixing Unit can be used with all urea dozers to achieve even NH3 distribution within the exhaust gas. The greatest benefit is experienced with airless injectors, which have rather large SMD (Sauter Mean Diameter) and when the injection must start at low temperatures. 

Proventia has extensively tested its DEF mixing technology in worst case conditions with no sign of wall wetting or urea deposits.