Fan Silencer for Steel Reheating Furnaces

The process

Reheating furnaces for rolling mills burn gas or oil with preheated combustion air from a recuperator. The combustion air blower is sized for the burner pressure at the hot air temperature, and the flue fan or stack damper controls furnace pressure.

The gas at the fan

Clean air that has passed through an air heater or recuperator. Density is lower than ambient, so the fan is selected at the hot condition and checked for motor load at cold start.

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.

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 steel reheating furnaces

Fan 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.