An overview of SCR Catalytic Converters
As with all catalytic converters, the Selective Catalytic Reduction (SCR) variety consists of a substrate, a catalytic coating and a housing.
The job of the substrate is to provide the necessary surface area for the chemical reactions to occur whilst also complying with the pressure-drop requirements of the system. Another consideration is that the channels through the substrate must not be too small otherwise they could get blocked up with ash or chaff. Whitebeam uses a range of substrate materials including metal foil, glass fibre and extruded ceramics. Many options of cell density are available too.
There is also a choice of catalytic coatings available depending on the temperature range in which operation is required. Catalytic reduction of NOx is possible between about 150-600°C but specific coatings tend to require a narrower range than this in order to achieve good conversion efficiency combined with durability.
In non-automotive applications, SCR catalytic converters tend to have long durability requirements, so they are normally designed in a modular way which enables dismantling for the cleaning and replacement of substrates. Whitebeam therefore designs housings with this in mind.