Steel mill fan

Steel mill fan is a general term for the supporting fans in the entire process of steel metallurgy, covering sintering, blast furnace, converter, heating furnace, dust removal, gas recovery, cooling and other processes. The working conditions are generally high temperature, high dust, sulfur-containing/chloride ion, flammable and explosive, with extremely high requirements for wear resistance, anti-corrosion, explosion-proof, sealing, and continuous operation reliability.

1、 Classified by process

1. The sintering main exhaust fan (sintering machine core) is a large double suction centrifugal fan that extracts sintering machine flue gas under negative pressure; Smoke contains a large amount of mineral powder, SO ₂, and water vapor, which are highly susceptible to wear and low-temperature corrosion, making it one of the most demanding fans in steel mills. Supporting large-scale oil stations and online monitoring of vibration temperature.

2. Blast furnace system fan

Blast furnace blower: a large axial flow fan that delivers high-pressure combustion air to the blast furnace, determining its production capacity; Constant pressure air supply.

Blast furnace gas booster fan: transporting blast furnace gas, flammable and toxic, nitrogen sealed, anti-static and explosion-proof.

3. The primary dust removal fan (OG fan) of the converter extracts the high-temperature dusty gas produced by the converter steelmaking process, which contains CO, and explosion prevention is the top priority; The smoke carries a large amount of iron oxide dust, and the impeller is prone to wear. Welding wear-resistant impellers are often used.

4. Heating furnace combustion support/exhaust fan combustion support fan provides combustion air; The induced draft fan extracts flue gas from the heating furnace, and the medium is high temperature, with some sulfur-containing corrosion.

5. Dust removal fan in steel mills for steelmaking, rolling, and crushing workshops, extracting iron oxide dust; Under high dust conditions, the impeller is wear-resistant and welded.

6. Cooling fan axial/centrifugal fan, used for rolling mill, equipment cooling, and machine side ventilation.

2、 Structural characteristics of the whole machine (mainly centrifugal)

Thickened welded casing+wear-resistant and anti-corrosion impeller+air inlet+bearing box+common base

Impeller: Q345/manganese plate, tungsten carbide overlay welding in high dust areas; 304/316L stainless steel is selected for sulfur-containing and chloride ion flue gas.

Sealing: labyrinth+carbon ring composite seal; Add nitrogen to blow and seal the gas fan to prevent gas leakage or air infiltration.

Bearings: Large units use sliding bearings+lubrication stations, equipped with high-level oil tanks, and power-off protection; Pre embedded temperature and vibration sensors for remote monitoring. Accessories: High temperature/anti-corrosion soft connection, spring shock absorber, imported air damper, muffler, explosion-proof electrical control cabinet, combustible gas interlock, anti surge system.

3、 Core Features

1. 24-hour uninterrupted operation, continuous production in steel mills, significant downtime losses, equipment reliability priority.

2. The working conditions are complex, taking into account one or more of wear resistance, high temperature resistance, corrosion resistance, and explosion resistance.

3. Large units are equipped with a thin oil lubrication system, online monitoring, and automatic alarm interlocking for exceeding limits.

4. Gas fans are equipped with anti surge return pipelines to prevent severe surge damage to equipment.

5. The whole machine is grounded to prevent static electricity, and the risk of sparks is strictly controlled in the gas area.

4、 Material selection

Sintering and converter dust removal (high temperature+mineral powder): shell Q235, impeller Q345+tungsten carbide overlay welding

Sulfur containing wet flue gas: 304/316L stainless steel

Gas medium: carbon steel, nitrogen protection for sealing system

5、 Key parameters for selection

1. Usage process: sintering/blast furnace/converter/heating furnace/dust removal

2. Media: dust content, temperature, presence of CO, sulfides, chloride ions

3. Airflow, full pressure/boost

4. Is it explosion-proof, does it require a thin oil station, online monitoring, nitrogen sealing, and anti surge

5. Adjustment method: imported baffle/frequency converter

6、 Installation points

1. Special fluorine adhesive tape is used for soft connection of high temperature and gas media to compensate for thermal expansion and isolate vibration.

2. Pipeline independent support, pipeline load must not be pressed against the fan flange.

3. Static cross connection of gas system pipelines and reliable grounding of the entire machine; Nitrogen replacement before startup.

4. The flange seal of the negative pressure flue gas system is tight, reducing air leakage and dew point corrosion.

5. A large fan base is used as a shock-absorbing foundation, matched with spring shock absorbers.

7、 Common faults

1. Dust erosion: Iron oxide and sintered ore powder wear the blades, the impeller becomes thinner and perforated, and the vibration surges

2. Dew point corrosion: When the flue gas temperature is below the dew point, acidic condensed water causes corrosion of the shell and impeller

3. The impeller accumulates dust and scale, and the dynamic balance is unbalanced

4. Sealing failure of gas fan, gas leakage or air infiltration, major safety hazard

5. Surge, excessive bearing oil temperature, abnormal oil supply at the lubrication station