Low NOx Burner
A low NOx burner reduces nitrogen oxides (NOx) primarily by lowering peak flame temperature and managing oxygen availability in the flame zone, while maintaining stability and acceptable CO.
How NOx is reduced
- Staged combustion: creates fuel-rich and lean zones to reduce peak temperature.
- Internal flue gas recirculation (IFGR): entrains products of combustion to dilute the flame.
- External FGR: intentionally recirculates flue gas into combustion air.
- Advanced mixing control: optimizes mixing intensity across loads.
Trade-offs to manage
- CO rise at low load if staging is too aggressive.
- Turndown limitations compared to standard designs.
- Higher sensitivity to draft, leakage, and fuel quality.
- More complex commissioning and tuning requirements.
Selection criteria
- Required NOx level and measurement basis (dry, @3% O₂, etc.).
- Application and furnace/boiler geometry constraints.
- Turndown ratio and load profile.
- Fuel type (NG/LPG/oil/biogas) and pressure stability.
- Controls: parallel positioning, O₂ trim, FGR control loop.