Metallurgical Coking Gas Detection Solution: Safeguarding High-Temperature, High-Risk Production

Metallurgical coking is a core upstream process in the steel industry, converting coking coal into coke through high-temperature pyrolysis while producing large amounts of coke oven gas and other by-products. This process generates complex gas emissions, presenting both resource recovery opportunities and serious safety and environmental challenges. Coke oven gas contains combustible components like hydrogen, carbon monoxide, and methane, mixed with toxic substances such as benzene, toluene, hydrogen sulfide, and carbon disulfide. Inadequate monitoring can lead to poisoning, fires, or explosions.

Recent incidents in coking enterprises have been linked to gas leaks or excessive emissions. Deploying professional online gas detection systems at critical points such as ovens, gas purification units, and tail gas emission points has become essential for safety and sustainable development. The Nexisense SGA-500 series online gas detectors are tailored for the complex conditions of metallurgical coking.

Major Gas Hazards in Metallurgical Coking

• Combustible gases: H₂, CH₄, CO — low explosion limits and highly flammable near ignition sources.

• Toxic and hazardous gases: H₂S, BTX (benzene, toluene, xylene), CS₂, NOx — long-term exposure damages respiratory and nervous systems and may be carcinogenic.

• Tail gas components: SO₂, particulate matter, VOCs — affecting ambient air quality and regulatory compliance.

According to GBZ 2.1-2019 and GB 16297-1996, the permissible limits are strict. For example, CO PC-TWA is 20 mg/m³, H₂S is 10 mg/m³, benzene is 6 mg/m³. Traditional detection methods struggle with continuous, accurate, and stable monitoring in high-temperature, humid, and dusty coking environments.

Why Online Gas Detection Systems Are Needed in Coking Production

Portable detectors are suitable for inspections but cannot cover 24/7 production areas such as gas pipelines, risers, bridge pipes, and chemical production workshops. Online fixed systems offer:

• Real-time concentration monitoring and trend analysis

• Automatic audible and visual alarms for over-limit conditions

• Integration with ventilation, shut-off, and sprinkling systems

• Data upload to control rooms or environmental platforms for remote supervision

High-temperature areas (e.g., carbonization chambers, heat recovery systems) require sensors that withstand extreme conditions. Nexisense SGA-500 series provides solutions capable of withstanding these environments.

Core Advantages of Nexisense SGA-500 Series Online Gas Detectors

• Supports multiple gases: CO, H₂S, CH₄, benzene, VOCs; single or multi-gas configurations

• Fast response: T90 ≤ 45s for most gases

• High precision: ppm or ppb resolution options

• Flexible output: 4–20mA, RS485 Modbus RTU for PLC/DCS integration

• High protection: IP65+, explosion-proof optional (Ex d IIC T6 Gb)

• Local display and alarm: HD screen shows concentrations and status; alarm ≥85dB

For high-temperature scenarios, two special configurations are available:

1. High-temperature detectors: withstand 250℃ gas directly

2. High-temperature sampling probes: up to 800℃ for insertion into ducts/pipes, cooled before sensor analysis

   
   

Recommended Detection Points in Coking Production

• Oven risers, bridge pipes, collection pipes: monitor CO, H₂, CH₄, H₂S

• Gas purification workshops: focus on benzene and H₂S

• Charging and pushing stations: VOCs and dust monitoring

• Tail gas emission points and plant boundary: SO₂, NOx, particulate matter

• Breathing zone height: fixed detectors forming a safety network for personnel

High-temperature points should use high-temperature probes; low-temperature zones can use standard detection heads.

Tail Gas and Ambient Air Online Monitoring System

Nexisense provides full pollution-source online monitoring systems (CEMS-like), including:

• Sampling probes + pretreatment unit (dehumidification, dust removal, cooling)

• Multi-parameter analyzer: SO₂, NOx, CO, O₂, particulate matter, flow

• Data acquisition and transmission: supports GPRS/4G/Ethernet upload to environmental platforms

Plant ambient air monitoring can be deployed at boundaries, offices, or sensitive residential areas to track VOCs, BTX, H₂S, protecting the environment and employees.

System Integration and Emergency Linkage

• Supports SGA-800 alarm controller networking

• Centralized multi-point monitoring

• Tiered alarms: warning + critical

• Automatic linkage: activate fans, sprinklers, shut-off valves when limits exceeded

Such systems can reduce gas leak response times to minutes, significantly lowering accident risks.

Installation, Maintenance, and Long-Term Reliability

• Avoid high vibration or direct high-temperature airflow areas for detection points

• High-temperature probes must be securely fixed with cooling water systems operational

• Use shielded cables to prevent EMI

• Monthly check of probe cleanliness and zero drift

• Quarterly calibration with standard gases

• Sensor life: 2–3 years, replace modules when necessary

  
  
  

FAQ

1. Which gases have the highest explosion and poisoning risks? CO, H₂, CH₄ are high explosion risk; H₂S, BTX, CS₂ are primary toxic gases.

2. How do high-temperature probes work at 800℃? Multi-stage cooling reduces gas to 40–60℃ before sensors.

3. Does SGA-500 support multi-gas monitoring? Yes, 1–3 gases per device; large plants use distributed deployment for full coverage.

4. How to meet regulatory online monitoring requirements? CEMS-like systems comply with HJ/T 397, HJ 818, provide real-time upload via 4G/5G/Ethernet, auto-calibration, fault diagnostics, and standard protocols (Modbus, HJ212).

5. How to prevent probe blockage in dusty, humid environments? Use pre-treatment units with filters, condensers, and anti-fouling; regular cleaning and calibration required.

6. What is the emergency response after an alarm? Immediate alarm → identify gas → activate ventilation → shut off valves → notify control and emergency teams → repair leak.

7. Explosion-proof requirements in coking areas? Use Ex d IIC T6 Gb or higher, with corrosion-resistant housings.

8. How to leverage long-term data for energy saving and emission reduction? Trend analysis identifies leaks, optimizes combustion, monitors purification efficiency, and supports energy efficiency projects.

Conclusion

Metallurgical coking is high-temperature, high-risk, and complex in gas composition. Manual inspection is insufficient. Nexisense SGA-500 online gas detectors provide high precision, extreme-condition resistance, and easy integration for full-chain process and tail gas protection.

Investing in a reliable gas detection solution reduces accident risks and supports sustainable, safe production. Nexisense helps coking enterprises make safety the foundation of production.