Compact selective catalytic reduction (ComSCR)

Johnson Matthey’s new ComSCR was developed for small to medium sized diesel and gas engines. ComSCR is the answer to the increasing demand for compact, highly efficient, all-in-one-systems.

The SINOX® ComSCR exhaust gas cleaning system uses selective catalytic reduction (SCR), an extremely effective NOx reduction technology. Harmful nitrogen oxides are converted to nitrogen and water using urea solution and SINOX honeycomb SCR catalyst. The key features of the honeycomb catalyst at the heart of the ComSCR system are large specific surface area, high activity and durability which allow compact dimensions, superior performance and long catalyst lifetime. The ComSCR systems are specifically designed for rugged modes of operation typical of marine, non-road and power generation with diesel engines and gas engines up to 4500 kW.

System features

  • 4 reactor sizes, modular configuration
  • Compact housing includes urea injection and mixing
  • Modular, compact urea dosing cabinets
  • Airless, multiple-injector dosing system
  • NOx sensor control (open, closed loop)
  • High NOx, CO and HC conversions, low NH3 slip


Compared with conventional SCR systems, the ComSCR has a very small footprint. The urea injection and mixing sections are built into the reactor. It is modular and can be fitted with different catalysts type i.e. SCR catalyst, oxidation catalyst and ammonia slip catalyst (ASC). It has a specially engineered flow field to achieve high NOx conversion rates in the very small reactor space. Because the mixing pipe is built-in, upstream reactor piping is not required. Reactor orientation can be either vertical or horizontal.

ComSCR Product Family

Technology C0 C1 C2 2 C2
Configuration rectangular round round double round
Dimensions (cm) 150x110x50 170x110x110 180x150x150 180x300x150
Urea injectors 1-2 2-4 2-6 4-12
Weight (kg) 200 400 600 1200
Engine power < 600 kW < 1 MW < 2.2 MW < 4.5 MW

General enquiries

Joseph McCarney


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    Betty Ann Keen

    North America

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