Opti-Flow™ –T Low NOx System for Tangentially-Fired (T-fired) Boilers
General Information
- Description
- CFD Results
- Emissions and Performance
Siemens applies the same systems approach to the development of equipment for T-fired boilers as for wall-fired boilers. Further, Siemens’ NOx control philosophy differs from the conventional designs and yields important benefits.
Conventional T-fired low NOx systems use large quantities of overfire air as the primary NOx control. But this can lead to furnace problems.
Siemens takes a different tack
- Use low NOx burner principles: reduce NOx at the burner where it is formed
- Then use OFA, like on the wall fired boilers we retrofit, as supplemental NOx control
The key is the effective Opti-Flow™ low NOx fuel injector
- Same fuel injector employed successfully in wall-fired applications
- Achieves early NOx control of volatile fuel nitrogen by producing effective low NOx burner flame conditions
- Controls thermal NOx by producing an internally staged flame
- Prevents NOx formation from atmospheric nitrogen - Minimizes amount of overfire air
- No deep staging of burner zone that can lead to corrosion and slagging problems
The following CFD comparisons of baseline and final cases show the improvement attributable to Siemens in three areas of interest.
Total Particle Mass Deposition Rate
CO Concentration
Typical results from a 300 MW T-fired boiler firing high sulfur, high slagging bituminous coal
- CO nearly eliminated along the walls from the hopper to the exit
- Simple design
- Lowest LOI and NOx
- No change in FEGT or CO
- Significantly less particle and UBC deposition on the walls
Results for this 300 MW boiler: no wall slag or corrosion. Therefore, no need to drop load to shed slag, and NOx reduced nearly 50%.
The Opti-Flow™ –T Low NOx Burner System provides modern, effective NOx control for tangentially-fired boilers.