Selective catalytic reduction (SCR) catalyst
Shell Catalysts & Technologies provides reliable technology for Selective Catalytic Reduction (SCR) of nitrogen oxides (NOx) from stationary and mobile combustion sources and chemical processes.
SDS can help you achieve required performance while consuming less energy.
Proven around the world, SDS catalyst technology provides high NOx reduction across a broad range of conditions. At one asset SDS achieved > 99% NOx reduction across a broad range of conditions.
Because of its Lateral Flow Reactor (LFR) based design, low-temperature activity and extremely low-pressure drop, SDS can help your operations achieve the performance you require while consuming less energy – supporting your facility’s overall energy reduction programme.
How does SDS work?
Our SDS technology is based on the addition of ammonia to off-gases that contain nitrogen oxide (NO) and nitrogen dioxide (NO2), which are commonly referred to as NOx. This mixture is then passed over an active Shell catalyst that converts the NOx to nitrogen (N2) and water (H2O).
A key advantage of our SDS system is the LFR-based design, which – owing to its high surface area and low-pressure-drop properties – can help optimise reactor performance for low-temperature operation while consuming less energy than conventional systems.
Furthermore, for some applications, the SDS system can be installed between the heat recovery steam generator and stack, which can help reduce installation costs, plant downtime and disruption.
Applications for the SDS
With a compact size and excellent performance at a variety of operating temperatures, SDS technology can be applied to a wide range of combustion, chemical and incineration processes, in new and existing facilities, thereby supporting net-zero ambitions and lower-carbon-footprint operations. Examples include:
Gas Turbines
Unlike alternative NOx-control technologies, our SDS system does not disrupt the operation of natural gas (or hydrogen-blended fuels) turbine or heat-recovery equipment
Waste-to-energy
SDS technology can remove NOx at low temperatures, which means it can be integrated at the end of flue gas treatment systems on waste-to-energy plants and with minimal or no gas reheat
Refinery heaters
Enhanced ammonia adsorption can accommodate changing flue gas streams and compositions, for example, high NO2 concentrations, while meeting performance expectations
Boilers
SDS technology enables outstanding operational performance, including low ammonia slip, low pressure drop, and tolerance against boiler and/or economiser tube rupture and direct water contact
Nitric acid and other chemical plants
Relative to an expander, SDS technology can be installed upstream, where pressures are higher, or downstream, where pressures and temperatures are lower
Catalyst manufacturing
Enhanced ammonia adsorption can accommodate changing flue gas streams and compositions, for example, high NO2 concentrations, while meeting performance expectations
Ethylene crackers
Significant performance advantages over conventional NOx-reduction methods are observed when low NOx and ammonia emission levels are required
Biomass
Enhanced activity enables the catalyst to tolerate contaminated gas streams
Discover all the benefits and applications of this technology by reading the Environmental Catalysts & Systems brochure.
About SDS and selective catalytic reduction (SCR)
Cost-effective NOx reduction
The Shell Catalysts & Technologies SCR Catalyst System is based on the addition of ammonia (NH3) to the NOx-containing flue gas and passing the mixture over an active catalyst. This converts the nitrogen oxides (NO and NO2) to naturally occurring nitrogen (N2) and water (H2O).
Together, our high-activity catalyst and low-pressure drop result in cost-effective NOx reduction. The SCR technology is impressively cost-efficient compared to other NOx control technologies.
At low temperatures, SDS outperforms other catalyst systems
This makes our DeNOx system a highly cost-effective retrofit for existing facilities where exhaust temperatures are low.
Backed by the strength of Shell, the SCR Catalyst System not only enables your powerful environmental and cost benefits, but it also comes with the service and support you expect from a respected global leader.
Explore the Shell Catalysts and Technologies portfolio
Carbon dioxide purification catalyst
High-performance catalysts to remove trace contaminants from carbon dioxide streams prior to further use in chemical, agricultural and/or food applications.
Dioxin Removal
Shell Catalysts & Technologies provides technology for the catalytic destruction of dioxins and furans from municipal solid and hazardous liquid waste incineration facilities.
Learn more about our DeNOX catalyst system
Boilers and turbines
The Shell DeNOx System offers outstanding operational performance, including low ammonia slip, low-pressure drop, tolerance against tube rupture and direct water contact.
Unlike alternative NOx control technologies, the Shell Catalysts & Technologies SCR Catalyst System does not disrupt turbine or heat-recovery equipment operation.
Furnace and heaters
For existing installations, no modifications to either the furnace or the heat recovery section are necessary. For new furnaces, the location of the SCR Catalyst System helps maximise the operational flexibility of the furnace.
The SCR Catalyst System offers significant performance advantages over primary NOx reduction measures when low NOx emission levels are required.
Waste incineration and biomass
High NOx removal capability at low temperatures allows the SCR Catalyst System to be integrated at the end of flue gas treatment systems on waste incineration plants with minimal or no gas reheat.
