DENOX-SCR catalysts for diesel engines

Topsoe’s automotive technology is based on our unique DNX catalyst, which has been optimised to comply with the very stringent demands of the automotive industry and has demonstrated exceptional performance and longevity.

Topsoe offers two DNX catalysts:

• the vanadium-based catalyst for exhaust system configurations where the catalyst is placed upstream a soot filter or when a soot filter is not required 
• the zeolite-based catalyst for high temperature applications, designed for the application where an SCR catalyst is located downstream soot filters with active soot regeneration

The catalysts are based on a lightweight fibre-reinforced ceramic structure with a high cell density.

SCR-catalyst application

The SCR catalysts can be produced with diameter up to 17.5". This unique feature makes it possible to install the SCR catalysts as one single catalytic brick in vehicles with engines up to the 16 litre class.

The vanadium-based catalyst

The catalytic active metals are vanadium and tungsten oxides on a carrier of titanium oxide. The catalyst is of a full body type, meaning that the walls in the channels are made of catalytic material.

Features

The vanadium-based catalyst features 

• excellent activity at low as well as high temperature operation
• unmatched longevity
• high PM reduction efficiency 
• high sulphur tolerance 
• high thermal and mechanical shock resistance 
• flexible sizes

A typical catalyst volume of 2.0 in relation to the engine cylinder volume results in a NOx and hydrocarbon removal of 85%. A simultaneous particulate matter reduction of 50% has been demonstrated in the European Transient test cycle.

The zeolite-based catalysts

The catalytic active materials are based on ion-exchanged zeolites.

Features

The zeolite-based catalysts feature

• excellent temperature stability up to 750°C 
• high activity 
• high thermal and mechanical shock resistance 
• flexible sizes

ASC – Ammonia Slip Catalysts for reduction of ammonia slip from the SCR catalyst

For Euro 6 and US 2010 applications very efficient ammonia slip catalysts have been developed.  

Features

The ammonia slip catalysts feature

• high activity
• excellent selectivity
• high thermal and mechanical shock resistance
• flexible sizes