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Automotive & Stationary Engines

Automotive & Stationary Engines


EnviCat™ DOC

The diesel oxidation catalyst is used to oxidize carbon monoxide, hydrocarbons, including the Soluble Organic Fraction (SOF) of diesel particulate matter. As the diesel engine is tuned lean, the exhaust contains upto 16% of Oxygen and under these conditions the reduction of NOx is limited. The CO is oxidised to carbon dioxide and the HC including the SOF are oxidised to carbon dioxide and water. As the SOF is a condensable hydrocarbon and contributes to particulate matter, the DOC also reduces SOF component of particulate matter by 20 – 40% depending on the operating conditions.

Süd-Chemie catalysts are designed to provide the highest activity at low temperatures for CO and HC. For use with Sulphur containing fuels, the catalysts are formulated along with an additive to suppress the oxidation of sulphur dioxide to particulate sulphates. They can be offered on both metallic as well as ceramic substrates.

For use in after-treatment systems fitted with downstream Diesel Particulate Filter and/or a SCR, Süd-Chemie Envicat™ DOC can be custom designed to oxidise controlled quantity of NO to NO2 to facilitate the oxidation of the soot on the DPF and accelerates the deNOx reaction on the SCR at low exhaust temperature to meet the global emission standards.

The Envicat™ DOC have been certified for complying with the legislated emission norms.


Three way catalysts (TWC) are used to simultaneously remove CO, HC and NOx from exhausts of spark ignited engines. The catalysts are designed to oxidize the CO and HC to harmless carbon dioxide and water and reduce the NOx to Nitrogen at the same time.

Süd-Chemie offers a broad range of Catalytic converters for mobile & stationary engines fuelled by Gasoline, LPG & CNG. The use of high thermally durable wash coats and an automated state – of – the – art coating technology ensures long life of the catalyst. The superior thermal stability of the wash coat and use of improved oxygen storage materials permits the catalyst to be mounted closer to the engine for better cold start activity.

The Quality of the catalysts are approved by the certifying agencies and are used by major OEM’s in India and abroad. The catalysts are designed to comply with the global legislated standards.

Catalytic converters are available on both Ceramic or Metallic honeycomb substrates, including structured substrates and also on other substrates (e.g. foams, wire mesh etc), which can be provided as per request.

TWC EnviCats can be custom designed to meet preset performance parameters for:

  • Compliance with legislated emission norms
  • Thermal and Mechanical Durability
  • Poison resistance

EnviCat™ SCR

Selective Catalytic Reduction (SCR) is a robust and cost effective technology for reduction of NOx from diesel exhaust. The NOx reacts with NH3 and is reduced to nitrogen and water even in the presence of oxygen. SCR is widely accepted as the best available control technology. Engine tuned for SCR, NOx control, offers high fuel efficiency.

Süd-Chemie offers a variety of innovative SCR catalysts to reduce NOx Emissions over a wide span of operating temperatures from 200°C to 600°C with proven durability.

Süd-Chemie’s Envicat™ SCR series are designed to suppress the formation of N2O even at near complete conversion of NH3. Envicat VWT SCR catalysts can resist poisoning from SO2 and alkalies and can be used effectively even with high “S” diesel fuel (500 ppm S).

Süd-Chemie’s EnviCat™ SCR catalysts can be supplied on both Ceramic and Metallic substrates.

EnviCat™ SCR catalysts systems are also available with an upstream urea Hydrolysis catalyst and a downstream Ammonia slip catalyst.

EnviCat™ Hydrolysis catalyst
The hydrolysis catalyst is a base metal oxide catalyst formulated to convert the aqueous urea (Diesel Exhaust Fluid) into ammonia upstream of the SCR and enhances the low temperature performance of the system. It allows full utilization of the SCR brick as the inlet portion of the catalyst is not required to decompose and hydrolyze the urea. Süd-Chemie offers the hydrolysis catalyst as a separate brick as well as a coated zone at the inlet end of the SCR catalyst.

EnviCat™ Ammonia Slip Catalyst
The ammonia slip catalyst is a precious metal catalyst formulated to control ammonia slip, typically to below 10 ppm. The ammonia slip catalyst becomes important when the SCR systems are designed for +90% of NOx conversion and need to operate with high ammonia to NOx ratio. It is positioned after the SCR reactor and is formulated to optimize the oxidation of Ammonia to Nitrogen and suppress the selectivity to undesirable side products such as N2O and NO.

EnviCat™ DPF

The exhaust of lean burn diesel engines contain particulate matter such as soot and soluble organic fractions that are a risk to both human health and the environment. These particulates are removed by installation of filter. As the pores of the filter get plugged during operation, it becomes necessary to regenerate the filters by burning of the soot. Soot can be burnt either by active/passive regeneration. In active regeneration, the uncoated DPF is regenerated periodically by injecting fuel into the hot exhaust upstream of the DOC and thus raising the temperature sufficient for the soot burnout with oxygen. This method needs catalysts that can withstand high temperature. In passive regeneration, NO2 is used to combust the soot at relatively lower temperatures than possible with oxygen. The NO2 is generated by oxidation of the NO in the exhaust gas on a upstream DOC of the filter or alternatively coated DPF (cDPF).

Süd-Chemie Diesel Particulate Filters offer innovative Catalytic solutions for active and passive regeneration.

Some of the typical combinations offered are :

  • DOC + Uncoated DPF
  • DOC + Coated DPF
  • cDPF

EnviCat™ DOC + uncoated DPF

These filters can be customized with an upstream DOC designed to generate adequate NO2 for soot burning on DPF. The DPF itself is uncoated. This combination is also available for active regeneration where the diesel fuel is injected upstream of the DOC to generate the temperatures required for soot burn out with oxygen.

EnviCat™ DOC + cDPF

This arrangement uses a cDPF to further facilitate the in situ formation of NO2 on the filter and simultaneously burn the soot as it forms. For some applications Süd-Chemie offers its proprietary cDPF coating for use as a standalone device that can overcome space limitations without compromising the conversion effeciency.

The innovative formulations are designed to attain high PM, CO and HC reduction in excess of 98% and can also dramatically reduces exhaust smoke and diesel odor.

EnviCat™ cDPF coatings can be offered on advanced materials substrate in various size and shapes : Cylindrical, Rectangular and Custom shapes



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