MODULEX and DUALOX® catalytic converters and converter-silencers

Johnson Matthey's MODULEXTM and DUALOX® catalytic converters for stationary engines were developed to satisfy the increasing demand for clean air technology combined with silencing.

Johnson Matthey's innovative and economical MODULEX and DUALOX catalytic converters are designed to accommodate oxidation catalysts and three-way catalyst elements to reduce exhaust emissions and noise, when used in combination with a silencer. The MODULEX and DUALOX catalytic converters are utilised to achieve clean air emissions limits in many engine applications, including gas compression, gas transmission, power generation, irrigation and pumping, and standby equipment. The MODULEX and DUALOX catalytic converters can be installed on rich-burn or lean-burn stationary gas engines or on stationary diesel engines and are pre-engineered for a wide range of engine sizes. The flexibility of the modular designs allows the use of different flange sizes and the addition of a silencer.

The MODULEX and DUALOX catalytic converters converters can be equipped with Johnson Matthey's HAPGUARD Monitor. The HAPGUARD was designed for use with catalytic converters equipped with oxidation catalysts and three-way catalysts to help engine operators remain in compliance with RICE NESHAP.

Catalytic converter Engine power Construction material
MODULEX C 50-500 HP Stainless steel
MODULEX B 250-2250 HP Carbon steel, stainless steel
DUALOX 2000 HP and larger Carbon steel, stainless steel


MODULEX and DUALOX catalytic converters and converter-silencers

  • Designed to minimise leaks and bypass to maximise conversions
  • Improved flow distribution for maximum catalyst utilisation
  • Easy catalyst access for installation, cleaning, replacement
  • Fuels: natural gas, LPG, propane, diesel, biodiesel, dual fuel
  • 4- cycle engines and 2-cycle engines
  • Used with oxidation catalysts and three-way catalyst elements
  • Available with integrated silencer


The MODULEX and DUALOX catalytic converters are ready-to-install modules, available in multiple sizes with no additional engineering required. Customised converters are also available. The converters are designed for easy access to the catalyst. The catalyst elements slide in and out for simple installation, service or replacement. Just provide us with your clean air requirements and our technical experts will recommend the model that best meets your needs. Both the MODULEX and DUALOX catalytic converters are available with an integrated silencer.

Our DUALOX converters are resistant to thermal and mechanical shock and can accommodate multiple catalyst elements that can be easily replaced or removed for cleaning. If you want the easiest installation and access in a catalytic converter, DUALOX is the choice for you. Its built-in enhancements make this a very maintenance-friendly product. For catalyst access, simply unbolt the hinged cover, slide each existing catalyst element out along its supporting track, remove and then slide in the replacement catalyst element.

General enquiries

Joseph McCarney

Betty Ann Keen