Vent Silencer for Rice Husk Fired Boilers

The process

Rice husk burns in a fluidised bed or on a grate and leaves an ash that is largely silica. The ash erodes anything it touches at velocity, so the ID fan is built with wear liners and the dust collector is placed ahead of it. Rice mills and husk-fired captive power plants run these boilers at steady load for long periods.

The gas at the fan

Rice husk ash is high in silica and among the most abrasive fly ashes a boiler fan handles. Blade wear is the limiting factor; wear liners, hard facing and a blade form that resists erosion set the 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 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 rice husk fired boilers

Vent Silencer in other processes

Information needed to select or quote

1. Gas volume and temperature. Actual flow at the inlet, normal and upset temperature, moisture.
2. Dust or pollutant. Inlet loading, particle size distribution, whether it is abrasive, sticky, hygroscopic or combustible; for gases, the species and concentration.
3. Required outlet. The emission limit or clean gas concentration the unit must meet.
4. Site. Available space and height, material of construction preferences, and how the collected material is to be discharged.