Diesel Oxidation Catalysts

Nett Technologies’ Diesel Oxidation Catalysts (DOC) are catalytic converters designed specifically for diesel powered engines and equipment.

DOC’s reduce Carbon Monoxide (CO) and Hydrocarbons (HC) including the Soluble Organic Fraction (SOF) of Diesel Particulate Matter (DPM). DOC’s are simple, inexpensive, maintenance free and suitable for all types and applications of diesel engines.

Norman G Clark offers Nett Technologies’ Diesel Oxidation Catalysts.


M-Series (Metallic) Diesel Oxidation Catalysts (DOC)

M-Series (Metallic) Diesel Oxidation Catalysts (DOC)

M-Series (Metallic) Diesel Oxidation Catalysts (DOC)

  • Metallic DOC technology
  • EPA verified for the stationary applications
  • Maintenance-free, reliable and cost-effective emission control solution
  • Available in both universal and direct-fit designs (Nett Technologies has a database of over 10000 direct-fit muffler designs)
  • Mufflers are built entirely from corrosion resistant materials: aluminized and stainless steels
  • Installation time and cost are reduced to a minimum
  • DOC Catalytic Mufflers match or surpass the original muffler in sound attenuation and back pressure characteristics with addition of superior emissions performance
  • Great at reducing deadly emissions, such as Carbon Monoxide (CO) and Hydrocarbons (HC)

M-Series – Technology

The M-Series line of Nett diesel exhaust catalytic converters utilizes metallic monolith catalyst supports. The supports are made from a corrugated, high temperature stainless steel foil. Packages of several foil layers are fitted in stainless steel housings and secured in place by stainless steel rings. A special herringbone foil corrugation pattern creates a mixed flow cell structure. Exhaust gases from the Diesel Oxidation Catalyst (DOC) are forced into the turbulent flow regime resulting in better contact between gas and catalyst, enhanced mass-transfer conditions, and higher conversion efficiency. Selected physical properties of Nett metallic monoliths are listed in the table below.

The catalyst is deposited onto the foil prior to forming the substrate. A special foil washcoating process provides unequaled control of washcoat uniformity, adhesion, and efficient catalyst use. Thick washcoat concentrations in cell corners, which are inherent for other designs of metallic substrates, completely disappear with the precoated foil technology.

Physical Properties of Nett Technologies Catalyst Monoliths (uncoated)
  Metallic Ceramic
Cell Density, cpsi 160 240 320 200 300 400
Wall Thickness, mm 0.05 0.05 0.05 0.30 0.21 0.18
Geometric Surface Area, cm2/cm3 19 23 26 18.5 23.6 27.2
Open Frontal Area, % 94 92 91 69 74 74
Bulk Density, g/cm3 0.43 0.53 0.59 0.53 0.45 0.45

D-Series (Ceramic) Diesel Oxidation Catalysts (Doc)

  • Ceramic DOC technology with Zeolites designed to extend the performance of diesel catalytic converters into the low temperature range
  • Maintenance-free, reliable and cost-effective emission control solution
  • Available in both universal and direct-fit designs (Nett Technologies has a database of over 10000 direct-fit muffler designs)
  • Mufflers are built entirely from corrosion resistant materials: aluminized and stainless steels
  • Installation time and cost are reduced to a minimum
  • DOC Catalytic Mufflers match or surpass the original muffler in sound attenuation and back pressure characteristics with addition of superior emissions performance
  • Great at reducing deadly emissions, such as Carbon Monoxide (CO) and Hydrocarbons (HC)

D-Series – Technology

The D-Series Diesel Oxidation Catalysts (DOC) are available on ceramic substrates. Round cordierite substrates with square cell geometry are used in all D-Series catalysts. Selected properties of the substrates are listed in Table 1 below.

Catalyzed substrates are wrapped in special packaging mat and packed into a steel container using the tourniquet packaging technology. Tourniquet is known as the best catalytic converter packaging technology, producing the most rugged and durable converters.

Ceramic substrates produce somewhat higher pressure drop than metallic substrates of the same dimensions, due to their thicker walls. However, for most applications the D-Series catalysts are sized larger than M-Series Diesel Oxidation Catalysts (DOC) are, in order to provide sufficient volume of the HC trap. By using D-Series catalyst substrates of larger diameter and larger frontal area, it is possible to achieve comparable pressure losses for the M-Series and D-Series catalysts when installed on identical engines.

Most pressure drop comparisons between the ceramic and metal catalyst supports are based on bare (uncoated) substrates. While the uncoated ceramic supports do have thicker walls (Table 1), the difference in wall thickness decreases after the catalyst coating is applied. This is explained by the inherent porosity of ceramic substrates, which “soak in” a portion of the catalyst coating into the wall pores. Since metallic substrates are not porous, the entire catalyst coating stays at their surface. Therefore, when the same loading of catalyst material is applied to a ceramic and a metallic substrate, it produces a thicker coating layer and more flow restriction in the metallic support.