The process
Utility and large industrial boilers fire pulverised coal through mills and burners. The PA fan dries and conveys the coal from mill to burner, the FD fan supplies secondary air through the air heater, the ID fan draws the flue gas through the ESP to the stack, and seal air fans keep coal dust out of the mill and fan bearings. These are the largest fans in the plant.
The gas at the fan
After the ESP or bag filter the flue gas carries a light residual ash load. The ID fan handles large volume at moderate temperature, selected for efficiency with modest wear allowance.
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 140°C the gas density is close to 0.85 kg/m³, 71% 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. |
An absorptive silencer at the fan inlet, outlet or in the duct, cutting fan noise with minimum pressure loss. Client-stated blade types for the Fan Silencer in general: Silencer.
Industries
Other fans in pulverised coal fired boilers
ID FanFD FanSA FanPA FanCombustion Air BlowerSeal Air BlowerDust Collector FanBag Filter FanVent SilencerVentilation FanCoal Mill Fan
Fan Silencer in other processes
Bagasse Fired BoilersRice Husk Fired BoilersAFBC BoilersCFBC BoilersOil and Gas Fired BoilersWaste Heat Recovery BoilersBiomass Fired BoilersThermic Fluid HeatersBlast Furnace Hot Blast StovesSinter PlantsSteel Reheating FurnacesPharmaceutical Clean RoomsRefinery Fired HeatersFlare and Pressure Relief SystemsGas Compressor StationsCaptive Power PlantsGenerator and Engine RoomsCar Parks and TunnelsNuclear Facility VentilationHospitals and LaboratoriesData Centres and Equipment RoomsDistillery Spent Wash Incineration Boilers
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.