The process
Straight grate and grate-kiln pellet plants move very large volumes of hot process gas between the drying, firing and cooling zones with process fans, and extract dust at the balling and screening. The process fans run hot and dusty at large size, and the gas flows are switched by dampers.
The gas at the fan
Sinter strand waste gas carries ore and flux fines with acid components from the sulphur in the fuel. Wear and corrosion both act on the wheel; material and liner selection follow the gas analysis.
Selection for this duty
| Blade form | Radial tipped with wear liners, or straight radial where the dust is coarse |
| Material of construction | Stainless steel on all wetted parts, grade to suit the gas analysis |
| 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 |
| 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. |
Circulates or supplies air at elevated temperature to a dryer, oven or kiln. Selected at the hot density with the shaft and bearing arrangement built for continuous hot running. Client-stated blade types for the Hot Air Fan in general: Backward curved and backward inclined.
Industries
Other fans in iron ore pellet plants
Hot Air Fan in other processes
Services on this fan
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.