Viability of video imaging spectro-radiometry (VISR) for quantifying flare combustion efficiency.

Area of Science:

• Environmental Science
• Chemical Engineering
• Spectroscopy

Background:

• Flares are critical in industrial processes for safely disposing of waste gases.
• Accurate measurement of combustion efficiency (CE) is vital for environmental compliance and process optimization.
• Continuous monitoring emission systems are increasingly important for detecting methane slip, as highlighted by initiatives like OGMP 2.0.

Purpose of the Study:

• To numerically assess the Video Imaging Spectro-Radiometry (VISR) technique for quantifying flare combustion efficiency (CE).
• To investigate the impact of spectroscopic model approximations on local and global CE calculations.
• To evaluate VISR's capability in capturing fuel stripped from the combustion zone under crosswind conditions.

Main Methods:

• Computational fluid dynamics (CFD) simulations of a steam-assisted industrial flare.
• Generation of simulated mid-infrared images (3.2–4.9 µm) targeting CO2, CO, and CH4 absorption bands.
• Analysis of pixel-wise CE, global CE estimation, and assessment of VISR's limitations with crosswind effects.

Main Results:

• Simplified VISR models can accurately predict local CE.
• The instrument model for converting local to global CE may introduce significant biases.
• VISR is likely unable to quantify unburned methane stripped by crosswinds, leading to overestimated flare performance.

Conclusions:

• While VISR shows promise for local CE assessment, its global CE calculations require refinement to avoid biases.
• The technique's inability to detect stripped methane under crosswinds poses a challenge for accurate emissions monitoring.
• This study provides a methodology for benchmarking emerging continuous monitoring technologies for flare emissions.