The process
Zero liquid discharge distilleries concentrate spent wash and fire it with bagasse or coal as support fuel in a slop fired boiler. The ash is high in potash and sticky, the gas is corrosive, and the ID fan is built for deposit and attack that a plain bagasse boiler fan does not see.
The gas at the fan
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.
Selection for this duty
| Blade form | Radial tipped with wear liners, or straight radial where the dust is coarse |
| Material of construction | Mild steel with replaceable wear liners on the blades and the scroll at the cut-off, with a casing drain for the moisture |
| Drive and bearings | Direct coupled or belt driven with a shaft cooling disc and bearings outside the casing |
| Also specified | Hard facing or liners on the blade pressure face; casing drain at the lowest point |
| Density at the fan | At about 170°C the gas density is close to 0.80 kg/m³, 66% 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. |
Supplies the secondary combustion air that completes burning above the grate or around the burner. On bagasse and biomass boilers it also carries the over-fire air that controls the fuel bed. Client-stated blade types for the SA Fan in general: Backward curved and backward inclined.
Industries
Other fans in distillery spent wash incineration boilers
ID FanFD FanPA FanCombustion Air BlowerSeal Air BlowerDust Collector FanBag Filter FanFan SilencerVent SilencerVentilation FanDilution Air BlowerHot Air Fan
SA Fan in other processes
Bagasse Fired BoilersRice Husk Fired BoilersAFBC BoilersCFBC BoilersPulverised Coal Fired BoilersBiomass Fired BoilersPulp Mills and Recovery BoilersCaptive Power Plants
Information needed to select or quote
- Duty point. Volume flow and static pressure at the fan inlet, with the gas density and temperature or the conditions to derive it.
- Operating conditions. Site altitude, normal operating temperature and continuous or intermittent duty.
- Gas stream. Dust loading and particle size, corrosive species, moisture, upset temperature and any tendency of the material to deposit on the impeller.
- Mechanical. Rotation viewed from the drive end, discharge orientation and motor power.