Cutting NOx in after-treatment


The reactor is the world's smallest and most compact NOx emission reduction system. The compact design allows for easy integration, and the few frame sizes will cover the entire 2-stroke portfolio up to 25 MW per SCR reactor.

High-pressure selective catalytic reduction

PBST offers the market's most compact SCR system. It reduces-through internal catalytic reaction - NOx exhaust emissions to current IMO Tier III limits. With specially developed honeycombs and honeycomb materials, as well as an integrated mixing unit, the overall size of the reactor has been drastically reduced compared to typical market designs and its medium speed counterpart.

Our advanced SCR-HP comes in six frame sizes, covering the entire 2-stroke engines portfolio up to 25 MW per reactor.


    • Improved compact design: the improved compact design, compared to conventional reactors, leads to considerable benefits for engine builders, shipyards and ship owners
    • One-source solution: PBST is the only manufacturer capable of delivering both exhaust gas after treatment solutions within the 2-stroke sector: high-pressure selective catalytic reduction, and exhaust - gas recirculation - including an electrical turbo blower. This allows 2-stroke customers to choose their preferred option as best fits their situation
    • Proven technology: the development of the new system is based on our in-house competence with 4-stroke engines, for which it can already reference more than 650,000 operation hours. 

    Technical data

    ClusterReactor diameter [mm]Reactor length [mm] <0.1% sulphurReactor length [mm] <3.5% sulphur

    Scope of delivery


    The system consists of the reactor - including mixing unit, urea injection lance, honeycombs and soot blowers - along with a module based supply system, as well as the reactor's control unit that communicates with the engine-control system. 

    The SCR-HP reactor can be mounted in each position and is capable of running on all fuels.