Applications
NOx Reduction with SCR Catalysts
Selective catalytic reduction turns NOx into N₂ and water — the catalyst geometry follows the dust, the chemistry follows the gas.
How SCR removes NOx
Selective catalytic reduction (SCR) converts nitrogen oxides to nitrogen and water in the presence of a reducing agent — typically ammonia — over a catalyst. The catalyst lowers the temperature at which the reaction proceeds to a practical operating window: V-Mo-Ti oxide systems work across roughly150–420°C. Two process routes exist in practice: high-dust SCR, where the reactor sits upstream of the dust collector and the catalyst faces raw flue gas; and tail-end SCR, where the catalyst sees clean gas. The route — not the chemistry — decides which catalyst geometry you need.
Plate vs honeycomb — the geometry decision
Plate-type SCR
Large pitch and open area for high-dust flue gas: power, cement, alumina — resists plugging and abrasion.
Honeycomb SCR
High specific surface in a compact volume — for low-dust or tail-end positions and tight layouts.
V-Mo-Ti chemistry
Vanadium-based oxide system with molybdenum promoter — the industrial standard for dust-laden NOx streams.
Selection checklist
| Dust loading | high-dust positions call for plate-type SCR with large pitch and open area; low-dust positions allow honeycomb. |
| Temperature window | catalyst activity is windowed; the reactor position in the process decides the temperature the catalyst sees. |
| Gas composition | SO₂ concentration and alkali metals in the dust affect catalyst formulation and lifetime. |
| Space constraints | honeycomb packs more active surface per volume; plate systems are more forgiving to dust. |
| Emission target | China's ultra-low-emission standards per industry set the removal-efficiency bar. |
Technical background: SCR DeNOx knowledge guide in our knowledge center.
Where our catalysts run
- Coal-fired power — high-dust SCR
- Cement — high-dust DeNOx
- Alumina — plate SCR
- Steel — multi-pollutant flue gas
- Sintering machines — CO oxidation + DeNOx
Dust decides geometry, chemistry decides the window
Send NOx inlet concentration, temperature, dust loading and SO₂ — we recommend the catalyst type and reactor position.