Measurement and Monitoring of Flare Gas Combustion Emissions

Flare gas combustion emissions are a critical focus in industrial environmental protection and resource management. Typically composed of unrecovered or unutilized hydrocarbon gases from refining and chemical industries, flare gas is burned in flare systems, producing water vapor and carbon dioxide. However, incomplete combustion or unignited gas releases can lead to harmful emissions, including unburned hydrocarbons and volatile organic compounds (VOCs), exacerbating air pollution.

Importance of Measurement and Monitoring

As global regulations tighten around methane emissions and environmental compliance, flare gas monitoring has become a critical focus for oil and gas operators. From upstream production sites to downstream processing plants, accurate measurement of flare gas is essential for safety, regulatory reporting, and environmental performance. Measuring flare gas combustion emissions helps assess combustion efficiency, detect abnormal releases (e.g., during startups, shutdowns, or power outages), and ensure regulatory compliance. Additionally, monitoring data optimizes flare system operations, reducing resource waste and greenhouse gas emissions. For instance, statistics indicate that prolonged flare gas combustion equates to burning millions of tons of standard coal annually, resulting in significant economic and environmental losses—making effective monitoring essential.

Challenges in Measurement and Monitoring

Flare gas often consists of a complex mixture of hydrocarbons and inert gases, such as methane (CH₄), ethane, CO₂, nitrogen, hydrogen sulfide (H₂S), and VOCs. The composition can vary rapidly, and flow conditions may range from very low to extremely high velocities, often under low or variable pressure.

Traditional flowmeters struggle in such environments, especially when:

  • The gas composition changes frequently

  • Pressure and temperature fluctuate

  • Intermittent or short bursts of gas must be captured accurately

Technology Selection and Application

Thermal mass flow meters are well-suited for measuring flare gas combustion emissions due to their ability to operate without temperature or pressure compensation, adapt to complex gas flows, and maintain low pressure loss. When combined with infrared or ultraviolet analyzers, they enable real-time detection of CO, CO2, and VOC concentrations. Advanced systems can integrate thermal imaging cameras to continuously monitor flame status, ensuring complete combustion. Intelligent monitoring platforms, leveraging data analysis, further optimize air-fuel ratios and thermal input, reducing emissions.

Flow Meter Comparison for Flare Gas Measurement

Flow Meter Type Advantages Limitations
Thermal Mass Flow Meter – Direct mass flow measurement without pressure/temperature compensation
– Excellent for low pressure, low velocity gas
– No moving parts, low maintenance		 – Sensitive to contamination and sudden changes in gas composition
– Not ideal for high-moisture or dusty environments


Ultrasonic Flow Meter

 – Non-intrusive, no pressure drop
– Wide turndown ratio
– Suitable for high-flow, high-pressure systems		 – High cost
– Requires long straight pipe runs for accurate measurement

Vortex Flow Meter

 – Robust design, handles high temperature and pressure
– Suitable for steady-state gas flow		 – Not suitable for low flow velocities or pulsating/intermittent flows
– Requires stable flow conditions

Practical Recommendations

It is recommended to use insertion thermal mass flow meters, designed for large-diameter pipelines, with regular sensor cleaning to address contamination. A split design with remote interfaces enhances efficient management. For high-pollution-risk scenarios, implementing a multi-parameter monitoring system ensures comprehensive compliance.
Reliable Flare Gas Measurement with Comate TGF600, a precise and maintenance-friendly solution for complex flare gas conditions.

Comate TGF600: Purpose-Built for Flare Gas

The TGF600 thermal mass flow meter by Comate is specially designed to overcome these challenges. It offers a direct mass flow measurement solution that works without the need for temperature or pressure compensation, greatly simplifying installation and reducing maintenance requirements.

Key Advantages:

  • Accurate measurement of mixed and fluctuating flare gases

  • Algorithm optimized for flare gas composition

  • Rugged thermal sensor design for heavy-duty conditions

  • No moving parts, low maintenance

  • Wide turndown ratio (up to 100:1)

  • Insertion installation – ideal for 25mm ~ 2000mm pipeline

  • Output options: Modbus, 4–20mA, pulse – ready for SCADA/EMS integration

📈 Typical Applications

  • Shale gas operations (e.g. Permian Basin, USA)

  • Offshore platform venting systems

  • Oil refinery flare stacks

  • Emergency pressure release lines

  • Associated gas flaring at well sites