Application of Industrial Methane Gas Detectors in Coke Plant Gas Leak Detection

The coking industry is a critical link in the steel industry chain. Through high-temperature dry distillation, coal is converted into coke, gas, tar, and other products, providing essential raw materials for metallurgy, chemical engineering, and related industries. However, this process involves the generation and transmission of large volumes of coke oven gas. Once leakage occurs, the consequences are often severe. Coke oven gas uses methane (CH₄) as its primary combustible component, featuring a high calorific value and a wide explosion limit (approximately 5%–36%). When exposed to open flames, it can easily cause fires or explosion accidents. In addition, inhalation of high concentrations of gas may lead to suffocation, poisoning, or even death. Therefore, deploying professional industrial methane gas detectors in critical areas of coke plants has become a rigid requirement for ensuring safe production.

In recent years, with increasingly stringent safety production regulations, standards such as the “Code for Design of Detection and Alarm of Combustible Gas and Toxic Gas in Petrochemical Industry” (GB50493-2009) have put forward clear requirements for gas leak monitoring. Enterprises are required to implement real-time and reliable monitoring at leakage-prone points such as gas pipelines, furnace bodies, purification workshops, and storage tank areas, enabling early hazard detection and reducing accident probability.

Risk Analysis of Coke Plant Gas Leakage

Coking production involves high-temperature and high-pressure environments. Coke oven gas mainly consists of methane (50%–65%), hydrogen, carbon monoxide, and other components, making it a typical high-calorific combustible gas. Leakage risks mainly originate from the following aspects:

• Poor sealing of coke oven doors, ascension pipes, and bridge pipes leading to gas escape;
• Aging flanges and valves or corrosion-induced perforation in gas pipelines;
• Equipment failures or operational errors in purification systems;
• Accidental leakage in gas storage tanks and compression station areas.

When the methane concentration in air reaches the lower explosive limit (LEL, 5%), ignition sources can trigger deflagration. As concentration rises toward the upper explosive limit, explosion power increases further. Historically, many coke plant gas explosion accidents were caused by undetected leaks and delayed alarm responses. Effective monitoring not only protects on-site personnel but also prevents equipment damage, production shutdown losses, and environmental pollution.

Core Functions and Advantages of Professional Methane Detectors

The Nexisense series industrial methane gas detectors are specifically designed for industrial environments and optimized for coke plant gas conditions. These products adopt industrial-grade aluminum alloy explosion-proof enclosures, comply with explosion-proof standards, and have obtained relevant certifications, ensuring long-term stable operation in flammable and explosive areas.

Key features include:

• Real-time online monitoring of methane concentration, with a measuring range covering 0–100% LEL;
• Large high-definition display simultaneously showing concentration value, unit, alarm status, and operating indicators;
• Support for multi-language interfaces (Chinese, English, etc.) for intuitive operation;
• Freely configurable three-level alarm thresholds, triggering audible and visual alarms above 85 dB when limits are exceeded, with one-key mute support;
• Built-in relay outputs enabling automatic interlocking with fans, shut-off valves, spray systems, and other equipment for rapid hazard mitigation;
• 4–20 mA analog output and RS485 digital signal output, supporting seamless integration with PLC, DCS, and SCADA systems;
• Full-range temperature and humidity compensation to ensure stable data under complex conditions;
• Data storage and export functions to facilitate post-event analysis and report generation.

These features allow Nexisense detectors to operate independently as single-point alarm devices or be integrated into plant-wide safety monitoring networks, forming multi-layered protection systems.

Typical Application Scenarios in Coke Plants

In practical deployments, Nexisense methane detectors are commonly installed in the following locations:

• Coke oven areas: near ascension pipes, gas collecting mains, and furnace top platforms to monitor gas dispersion;
• Gas pipeline corridors: fixed detection points along transmission lines to cover long-distance transport risks;
• Purification workshops: around benzene washing towers, desulfurization towers, and blower rooms;
• Gas storage tank areas and compression stations: surrounding tanks and valve groups for comprehensive coverage.

When abnormal methane concentration increases are detected, the system immediately triggers local audible and visual alarms. Simultaneously, relay outputs interlock ventilation equipment or close relevant valves to prevent further accumulation. Remote signal transmission allows the central control room to monitor real-time data from all points, enabling rapid response and coordinated dispatch.

Practical application cases show that after introducing the Nexisense series, a medium-sized coke enterprise successfully identified and addressed potential leaks multiple times when concentrations approached alarm thresholds, preventing possible accidents and significantly enhancing on-site safety levels.

Installation and Routine Maintenance Guidelines

During installation, monitoring points should be selected based on plant wind direction, equipment layout, and gas diffusion models to ensure sensors are located in areas where gas is likely to accumulate. The explosion-proof enclosure design simplifies deployment in outdoor or semi-outdoor environments, offering high protection ratings and strong corrosion resistance.

For maintenance, it is recommended to:

• Perform zero-point and span calibration regularly (every 3–6 months);
• Check sensor probe cleanliness to prevent dust or tar adhesion from affecting response;
• Verify alarm and interlocking functions to ensure relay outputs operate correctly;
• Review historical data via software to analyze trends and identify early signs of sensor aging.

When combined with digital management platforms, enterprises can achieve remote monitoring and predictive maintenance, further reducing operation and maintenance costs.

Safety Benefits and Long-Term Value

The direct benefits of deploying professional methane detectors are clear: reduced accident probability, lower risk of casualties, and avoidance of major property losses. At the same time, compliant monitoring data supports safety and environmental inspections, enhancing corporate credibility.

In the long term, as “dual-carbon” goals advance, the coking industry is accelerating its green transformation. Efficient gas leak monitoring is not only a safety baseline but also an important means to optimize energy utilization and reduce fugitive greenhouse gas emissions. With reliable performance and flexible integration capabilities, the Nexisense series helps enterprises achieve a better balance between safety and efficiency.

Frequently Asked Questions (FAQ)

1. What are the main components of coke oven gas?   It is mainly composed of methane (CH₄) at approximately 50%–65%, along with hydrogen, carbon monoxide, nitrogen, and other gases, featuring high calorific value and wide explosion limits.

2. Why must coke plants install methane detectors?   Gas leaks can easily cause explosions or poisoning accidents. Real-time monitoring provides early warning and interlocked responses to ensure personnel and equipment safety.

3. What is the measuring range of Nexisense methane detectors?   Typically 0–100% LEL, customizable according to on-site requirements.

4. What signal output methods are supported?   4–20 mA analog output, RS485 digital output, and relay switch outputs for integration with various control systems.

5. How are devices interlocked after an alarm is triggered?   Through built-in relay outputs, fans can be started, valves closed, or other emergency equipment activated automatically.

6. Are the detectors stable in high-temperature and high-humidity environments?   Yes. Full-range temperature and humidity compensation technology ensures accuracy and long-term stability.

7. How is routine calibration performed?   Standard calibration gas is used for zero and span calibration, typically every 3–6 months.

8. What practical benefits does the system provide after deployment?   Significant reduction in accident risks, improved compliance, optimized maintenance efficiency, and data support for digital safety management.

Conclusion

In high-risk industrial environments such as coke plants, industrial methane gas detectors are indispensable safety barriers. With robust and explosion-proof design, real-time monitoring, precise alarms, and rapid interlocking capabilities, the Nexisense series provides efficient and reliable gas leak prevention solutions. Through scientific deployment and standardized maintenance, it safeguards personnel and property while supporting the coking industry’s transition toward safer, greener, and smarter operations.