The process
Recovery boilers, lime kilns and digesters in a pulp mill need the boiler fan set, non-condensable gas handling, and scrubbing of odorous gases. Corrosion and odour are the design concerns alongside the usual boiler duties.
The gas
Mixed biomass fuels give variable ash and moisture. The fan is sized for the worst fuel in the mix, with wear protection and deposit shedding as for bagasse.
Fans in this process
| Duty | What it does here | Type usually selected |
|---|---|---|
| ID Fan | Sits at the outlet of a boiler, kiln or furnace and draws the flue gas through the plant to the stack. | Backward curved, backward inclined and radial tipped |
| FD Fan | Supplies combustion air to a boiler or furnace, pushing ambient air through the air heater and into the windbox against the furnace draft. | Backward curved and backward inclined |
| SA Fan | Supplies the secondary combustion air that completes burning above the grate or around the burner. | Backward curved and backward inclined |
| Dust Collector Fan | The fan behind a bag filter, cyclone or multiclone on a dust extraction system. | Backward inclined and radial tipped |
| Fume Exhaust System | Hoods, ducting and an exhaust fan that capture fume at source and deliver it to a scrubber, bag filter or stack. | Backward inclined and radial tipped |
| Vent Silencer | Cuts the noise from steam or gas expanding from high pressure to atmosphere at safety valve outlets, start-up vents and blow-down lines.. | Silencer |