The process
A circulating fluidised bed boiler recirculates solids through a hot cyclone and loop seal. The primary air fan runs at high pressure to fluidise the bed, the secondary air fan stages combustion, and the ID fan handles the flue gas after the cyclone and ESP. Loop seal and fluidising blowers add high pressure duties around the furnace.
The gas at the fan
Circulating fluidised bed boilers return most solids through the cyclone, so the flue gas reaching the fan carries fine ash at moderate loading. Erosion is slower than on an AFBC unit but still sets the wheel design.
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 150°C the gas density is close to 0.83 kg/m³, 69% 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 cfbc boilers
ID FanFD FanSA FanPA FanCombustion Air BlowerSeal Air BlowerDust Collector FanBag Filter FanVent SilencerVentilation FanHigh Pressure Blower
Fan Silencer in other processes
Bagasse Fired BoilersRice Husk Fired BoilersAFBC BoilersPulverised Coal Fired 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.