The process
A sugar mill boiler fires bagasse straight from the mill at around half moisture. The fuel bed needs a large volume of under-grate air from the FD fan and over-fire air from the SA fan, and the wet, fibrous fly ash leaving the furnace goes to a multiclone or wet scrubber before the ID fan. The season runs for months without a stop, so every fan on the boiler is sized for continuous hot running and for ash that builds up on the blades.
The gas at the fan
Flue gas from bagasse firing carries a heavy load of fibrous fly ash and unburnt char, with high moisture from the wet fuel. The ash is abrasive and tends to build up on blades, so the wheel is chosen to shed deposit and the blades carry wear protection.
Selection for this duty
| Construction | Absorptive annular design in mild steel; stainless steel where the gas is wet or corrosive |
| Density at the fan | At about 180°C the gas density is close to 0.78 kg/m³, 65% of standard air. Pressure developed and power drawn fall in the same ratio, so the selection is made at this density and the motor is checked at cold start. |
Cuts the noise from steam or gas expanding from high pressure to atmosphere at safety valve outlets, start-up vents and blow-down lines. Client-stated blade types for the Vent Silencer in general: Silencer.
Industries
Other fans in bagasse fired boilers
Vent Silencer in other processes
Information needed to select or quote
- Gas volume and temperature. Actual flow at the inlet, normal and upset temperature, moisture.
- Dust or pollutant. Inlet loading, particle size distribution, whether it is abrasive, sticky, hygroscopic or combustible; for gases, the species and concentration.
- Required outlet. The emission limit or clean gas concentration the unit must meet.
- Site. Available space and height, material of construction preferences, and how the collected material is to be discharged.