The tail gas from the calcium carbide furnace originates from a closed‑type calcium carbide furnace, with approximately … cubic meters of furnace gas produced per ton of calcium carbide. 400Nm ³, primarily used as fuel in lime kilns, rotary kilns, and coke ovens, and can also serve as a chemical raw material.

I. Characteristics of Calcium Carbide Furnace Off-Gas:

1 , Gas composition (volume fraction) CO ： 70-90%   The main combustible component is highly toxic and flammable/explosive; H ₂   2-8% Hydrogen burns rapidly;

CO₂ 2–5% inert diluent. Oxygen content is strictly controlled to prevent explosions.

• Heating value: 2300-2600 kcal/Nm ³ (approximately 11.5-3  MJ/m ³), classified as a medium-to-low calorific gas.

•出炉 temperature: 400-800 °C, with significant operating condition fluctuations.

• Dust content: Original 50-150g/Nm ³, the dust is CaO , coke powder, SiO Secondary fine particles; must be dust‑removed before being fed to the burner, typically with baghouse filtration achieving < 50mg/Nm ³

• Tar issue: Temperature below 180-200 At °C, tar precipitates and binds with dust, clogging pipelines and burners; the conveying pipelines must be insulated to maintain > 220 °C, to prevent coking tar scaling

• Impurities: trace amounts HCN Sulfides, phosphorus arsenic fluorides are toxic and corrosive; the system must be tightly sealed to prevent leaks.

• Pressure and Gas Flow: Pressure fluctuations occur, and gas flow varies significantly with changes in the calcium carbide furnace’s production load. CO The risk of explosion is high; the entire system must be nitrogen‑purged and protected against backflow of air.

Summary of Key Challenges: CO High proportion, high toxicity, and dust-containing. +  Tar tends to clog the burner, gas flow rate and calorific value fluctuate, and hydrogen poses a flashback risk.

II. Key Technical Points of Calcium Carbide Furnace Off-Gas Burners (Nozzles)

Acetylene furnace off-gas cannot be directly used as ordinary natural gas. /  Coke oven gas burners must be equipped with specially designed, custom‑made nozzles. Typical application areas include lime kilns, zinc oxide rotary kilns, ladle preheaters, waste‑heat boilers, incinerators, dryers, and hot‑air furnaces, among others.

1 , Burner Design Requirements

1 ) Anti-clogging structure

• A large‑diameter flow channel prevents fine dust and tar deposits from clogging the nozzle; no fine micro‑porous nozzles are used.

• Material selection for the burner head 310S ( Cr25Ni20 ) Stainless steel or silicon carbide, high-temperature resistant 1200-1300 ℃, resistant to dust‑induced erosion and corrosion.

2 ) Combustion configuration

• Multi-purpose swirl +  External‑mix combustion configuration; strong premixing is not advisable; flameout suppression (exhaust gas contains… H ₂, with a pronounced tendency to tempering;

• Automatic air-fuel ratio adjustment, adapting to fluctuations in exhaust gas calorific value and gas flow rate, ensuring… CO Complete combustion, minimizing exhaust emissions. CO Exogenous poisoning;

• Graded air distribution, reducing NOx , combustion is complete.

3 ) Ignition and Safety Interlock

• Staged ignition: pilot light /  First ignite the pilot burner; once the pilot burner is burning steadily, switch to the main tail‑gas fuel to prevent deflagration.

• UV Ultraviolet flame detection; in the event of flameout, the gas supply is immediately and rapidly shut off, with alarm interlock.

• Gas pressure high/low protection and nitrogen purging/replacement interlocks; can be connected to… DCS Remote control.

4 ) Flame configuration adapted to the kiln

• Rotary kilns and lime kilns: long-flame type;

• Roasting burner: flexible long flame;

• Boiler: Short-flame, high-rotation.

2 The importance of upstream purification for burners: the service life of a burner largely depends on front-end purification.

1.  Dust collection (baghouse filtration) must be installed, and dust levels should be kept as low as possible. 50mg/Nm ³;

2.  The pipeline is fully insulated to maintain a gas temperature greater than 220 ℃, preventing the condensation and precipitation of tar; once the tar… +  Dust scaling causes the burner to clog and fail rapidly.

3.  Install water seals, flame arrestors, and nitrogen seals to prevent backfire propagation and the backflow of air into the gas pipeline.

3 , Common Faults

1.  Coking and blockage at the burner nozzle: tar condensation. +  Dust mixing occurs because the pipeline temperature is too low, leading to ineffective dust removal.

2.  Tempering: improper premixing structure, high hydrogen content, and pressure fluctuations.

3.  Incomplete combustion, outlet CO Out of specification: air-fuel ratio imbalance, with no automatic adjustment for fluctuations in air flow.

III. Brief Selection Guidelines

1.  Fuel: Purified, sealed acetylene furnace off-gas, with a calorific value of 2300-2600kcal/Nm ³;

2.  Turndown ratio: recommended ≥ 5:1 , to accommodate fluctuations in the calcium carbide furnace load;

3.  Material: Burner head 310S or a silicon carbide structure;

4.  Security Configuration: UV Flame detector, gas high- and low-pressure switches, emergency shut-off valve, pilot burner, nitrogen purging interface;

5.  Included components: flame arrester, water seal, gas venting system, and a complete safety interlock system.

Acetylene Furnace Off-Gas Combustion and Application Technology Information

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