Emission Control
Selective catalytic reduction systems that convert NOx to nitrogen and water across the load profile: urea dosing, mixing and catalyst sized to your exhaust temperature, permit limit and back-pressure budget, and integrated with the silencer where space is tight.
Exterior Interior See It Inside
Drag the handle to compare the closed casing with the cutaway and follow the gas from urea injection through the mixing section to the catalyst face.
An SCR system injects an atomised urea solution into the hot exhaust, where it decomposes to ammonia; a mixing section gives the droplets length to evaporate and spreads the ammonia evenly across the duct; then the gas passes the catalyst, where ammonia reduces NOx to nitrogen and water vapour. The catalyst (vanadium or zeolite) is chosen for the exhaust temperature window, and dosing is metered against engine load so conversion stays high without sending unreacted ammonia out of the stack.
Built To Your Specification
The chemistry of SCR is straightforward; the engineering is in the application: flow and temperature across the load profile, fuel and sulphur, permitted slip, back-pressure and available space. Credible sizing is always project-specific.
We take the engine, turbine or boiler data, the flow and temperature across the real load profile, the fuel and sulphur level, the permitted ammonia slip and the NOx limit named in the permit.
Engineers select the catalyst family and volume, size the injection and mixing for even ammonia distribution, and set the dosing control, balancing NOx conversion, slip and pressure drop.
The reactor (with replaceable catalyst layers and, where space is tight, an integrated exhaust silencer) is fabricated and quality-checked at our own facility.
Systems are installed and commissioned to the guaranteed stack value, with a bypass for start-up and low-load running and documentation handed over on completion.
From the Knowledge Hub
The reaction chemistry that turns NOx into nitrogen and water, the urea-to-ammonia dosing system, the catalyst families and their temperature windows, and what really determines conversion efficiency in an exhaust line.
Read the articleCapabilities
What deep NOx reduction demands beyond the catalyst itself.
Compliance
Deep reduction (often around 90%) sustained across the load profile to meet the limit named in your permit, from the EU Medium Combustion Plant Directive to IMO Tier III at sea.
Catalyst
Vanadium or zeolite catalyst selected so the gas sits inside the active window across the real load profile, not just at the design point, with replaceable layers for ageing margin.
Slip & flow
Catalyst volume, dosing and mixing balanced so conversion stays high without ammonia slip past the permit cap, or pressure drop the engine supplier won’t accept. On-line ammonia-slip measurement closes the dosing loop, holding slip under the cap as load swings and the catalyst ages.
Integrated
Where space is tight (gensets, ships, backup power) the reactor and exhaust silencer are combined in a single casing, delivering NOx conversion and noise attenuation within one pressure-drop budget.
Reference project
Confidential datacenter operator
Axces packaged DOC, DPF and SCR with a silencer, chimney and continuous emissions monitoring into one container, then standardised it across 21 backup gensets, achieving up to 95% NOx reduction in line with Switzerland’s LRV air-quality limits.
Applications
Diesel, gas and biogas engines, turbines and boilers, wherever the permitted NOx limit is below what in-engine measures alone can reach.
Data centers
Emergency standby diesel generators on hyperscale campuses, where SCR brings NOx within the limit, often integrated with the exhaust silencer.
Read morePower generation
Reciprocating-engine and gas-turbine plant meeting the MCP Directive and national NOx limits across the dispatch profile.
Read moreMarine & offshore
Marine diesel engines meeting MARPOL Annex VI Tier III in NOx emission control areas, with urea dosing matched to the duty.
Read moreOil & gas
Fired heaters, boilers and engine drives on process plant, where SCR cuts NOx without a residue to dispose of.
Read moreIndustrial & EPC
Complete SCR (reactor, dosing and controls) delivered to EPC contractors as part of a single emission-control scope.
Read moreSend us the engine or turbine data, the flow and temperature across the load profile, the fuel and the permitted slip. We’ll size an SCR system to the limit in your permit.
