Typical Application Scenarios: High-Risk Areas Across the Metallurgical Process

The metallurgical production process includes raw material handling, smelting (blast furnace/converter/electric arc furnace), refining, continuous casting, rolling, and auxiliary systems (e.g., gas holders, dust removal facilities). Key gas risk points in each stage are as follows:

(1) Raw Material Handling and Sintering Areas

● Main Risks: Sintering machines (which agglomerate iron ore powder into blocks via high-temperature sintering) burn fuels (e.g., coke, natural gas), potentially producing CO due to incomplete combustion. Sulfur in raw materials decomposes into trace H₂S at high temperatures. Confined spaces like sintered ore bins or conveyor belt undersides may accumulate CO.

● Monitoring Focus: Sintering machine head/tail (combustion zones), ore bin interiors (confined spaces), and sintered ore cooling areas (potential CO residues).

(2) Blast Furnace Ironmaking Area

● Core Risk Points:

1) Blast Furnace Top and Tuyere Platform: The furnace generates large volumes of CO (20%–30% of the gas mixture) through reactions between carbon and oxygen/blast air. Leaks from gas pipelines (e.g., blast furnace gas pipelines) or valves can disperse CO to the platform and surrounding areas. The tuyere zone, with its high-temperature, oxygen-rich environment, may also produce CO due to localized incomplete combustion.

2) Gas Pipelines and Valve Rooms: Blast furnace gas (primarily CO, N₂, CO₂, with ~25%–30% CO) is transported via pipelines to downstream processes. Interfaces, flanges, and pressure-reducing valves are prone to leaks due to corrosion, vibration, or aging.

3) Gravity Dust Collectors/Baghouse Dust Collectors: Used to remove dust from blast furnace gas, accumulated dust may ignite due to high temperatures or friction, posing explosion risks if gas leaks occur.

● Monitored Gases: CO (primary), hydrogen (if using hydrogen-rich reduction technologies), methane (if gas contains impurities).

(3) Converter/Electric Arc Furnace Steelmaking Area

● Converter Steelmaking:

1) Oxygen Blowing Stage: Pure oxygen is blown into the converter to react with carbon in molten iron, generating CO (150–200 m³ per ton of steel). High CO concentrations (hundreds to thousands of ppm) occur near the furnace mouth and tapping spout. Furnace lining damage or oxygen lance water leakage may also produce hydrogen (H₂) ().

2) Gas Recovery System: Converter gas (60%–70% CO, with extremely high explosion risks) is recovered after dust removal and transported via pipelines. Pipelines, valves, and gas holders (pressure vessels storing converter gas) are high-risk leakage points.

● Electric Arc Furnace Steelmaking: Scrap steel melting may release CO, H₂, and trace methane if residual oil or plastics (containing hydrocarbons) on the scrap surface decompose during heating. Poor furnace cover sealing can allow CO to escape into the operator platform.

● Monitored Gases: CO (core), hydrogen (converter), methane (electric furnace scrap-derived).

(4) Refining and Continuous Casting Areas

● Refining Furnaces (e.g., LF Furnace, VD Furnace): Adjust steel composition via argon blowing and alloy addition. Sulfur-containing alloys or fluxes may release trace H₂ Inert gases (argon or nitrogen) used for shielding may leak, displacing oxygen and causing local oxygen deficiency (O₂<19.5% VOL).

● Continuous Casting Platform: High-temperature radiation from molten steel may decompose hydraulic oil or lubricants in surrounding equipment, producing CO or other flammable gases. Poor sealing in the mold may lead to CO accumulation.

● Monitored Gases: CO (refining/continuous casting), H₂S (refining), oxygen (oxygen deficiency), nitrogen (if used for shielding).

(5) Rolling and Heat Treatment Areas

● Heating Furnaces (e.g., Soaking Pit Furnace, Walking Beam Furnace): Fueled by natural gas (CH₄) or blast furnace gas, incomplete combustion produces CO. Poor furnace sealing or pipeline leaks lead to CH₄/CO accumulation. High temperatures may cause lubricants or seals to decompose, releasing VOCs (e.g., benzene series).

● Annealing Furnaces/Bright Annealing Furnaces: Using hydrogen as a protective atmosphere (e.g., for stainless steel bright annealing) poses high hydrogen leakage risks (explosive limit: 4%–75%). Nitrogen/argon shielding requires oxygen concentration monitoring to prevent asphyxiation.

● Monitored Gases: CO (fuel-fired furnaces), CH₄(natural gas furnaces), hydrogen (protective atmosphere furnaces), oxygen (oxygen deficiency), VOCs (organic volatiles).

(6) Auxiliary Systems: Gas Holders, Dust Removal, and Ventilation Facilities

● Gas Holders (Blast Furnace/Converter Gas Storage): Store large volumes of flammable gas (high CO content). Leaks from welds, seals, or valves can cause explosions. Gas stratification (CO settles at the bottom) requires multi-level concentration monitoring.

● Dust Removal Facilities (Electrostatic Precipitators, Baghouse Filters): Collect metallurgical dust. Internal dust accumulation may self-ignite or cause explosions if gas leaks occur. Gas concentrations at inlet/outlet pipelines need real-time monitoring.

● Ventilation Systems: Remove CO, H₂, and other gases from workshops. Ventilation failure (e.g., fan malfunctions) leads to rapid gas concentration buildup, requiring monitoring of ventilation outlets and key workshop areas.