Quantifying flare combustion efficiency using an imaging Fourier transform spectrometer

ABSTRACT

Mid-wavelength infrared (MWIR) imaging Fourier transform spectrometers (IFTSs) are a promising technology for measuring flare combustion efficiency (CE) and destruction removal efficiency (DRE). These devices generate spectrally resolved intensity images of the flare plume, which may then be used to infer column densities of relevant species along each pixel line-of-sight. In parallel, a 2D projected velocity field may be inferred from the apparent motion of flow features between successive images. Finally, the column densities and velocity field are combined to estimate the mass flow rates for the species needed to calculate the CE or DRE. Since the MWIR IFTS can measure key carbon-containing species in the flare plume, it is possible to measure CE without knowing the fuel flow rate, which is important for fenceline measurements. This work demonstrates this approach on a laboratory heated vent, and then deploys the technique on two working flares: a combustor burning natural gas at a known rate, and a steam-assisted flare at a petrochemical refinery. Analysis of the IFTS data highlights the potential of this approach, but also areas for future development to transform this approach into a reliable technique for quantifying flare emissions.

Implications: Our research is motivated by the need to assess hydrocarbon emissions from flaring, which is a critical problem of global significance. For example, recent studies have shown that methane destruction efficiency of flaring from upstream oil may be significantly lower than the commonly assumed figure of 98%; work by Plant et al. , in particular, suggest that this discrepancy amounts to CO₂ emissions from 2 to 8 million automobiles annually, considering the US alone. Similarly, the international energy agency (IEA) estimates a global flare efficiency of 92%, which translates in 8 million tons of CH₄ emitted by flares in 2020. Highlighted by these studies and supported by the World Bank initiatives toward zero routine flaring emissions, there is an urgent need for oil and gas industry to assess their flare methane emission, and overall hydrocarbon emissions. At the very least, it is critical to identify problematic flare operating conditions and means to mitigate flare emissions. Focusing on remote quantification of plume species, the measurement technique and quantification method presented in this paper is a considerable step forward in that direction by computing combustion efficiency and key components for destruction efficiency.

Acknowledgment

This research was sponsored by NSERC’s FlareNet (NETGP 479641-15). The authors are grateful to Defence Research and Development Canada for providing their Imaging Fourier Transform Spectrometer.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are openly available in “Replication Data for: Quantifying Flare Combustion Efficiency using an Imaging Fourier Transform Spectrometer” at https://doi.org/10.5683/SP3/JLMYWE.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/10962247.2024.2319773.

Additional information

Funding

The work was supported by the Natural Sciences and Engineering Research Council of Canada [FlareNet NETGP 479641 - 15].

Notes on contributors

Paule Lapeyre

Paule Lapeyre is a Postdoctoral Fellow at the University of Waterloo who specialized in radiative heat transfer. Her work is focused on hyperspectral imaging of flares and inversion techniques to quantify flare combustion efficiency.

Rodrigo Brenner Miguel

Rodrigo Brenner Miguel is a Mechanical Engineer and Scientific Researcher specialized in radiative heat transfer and optical diagnostics. His Ph.D. is on multispectral and hyperspectral imaging and flare combustion efficiency quantification.

Michael Christopher Nagorski

Michael Christopher Nagorski is a Mechanical Engineer specialized in radiation heat transfer and thermal engineering. His Master’s thesis is on optical gas imaging and optical flow algorithms.

Jean-Philippe Gagnon

Jean-Philippe Gagnon is a Field Application Engineer at Telops Inc. He is specialized in hyperspectral infrared cameras and works on quantifying emissions from the oil and gas industry as well as the maritime industry.

Martin Chamberland

Martin-Chamberland is a Co-Founder of Telops Inc. He is specialized in infrared hyperspectral imaging and works on developing ground-based and aircraft-mounted hyperspectral cameras.

Caroline Turcotte

Caroline Turcotte is a Defense Scientist working at Defence Research and Development Canada (DRDC). She is specialized in airborne infrared hyperspectral imaging.

Kyle J. Daun

Kyle J. Daun is a Professor at the University of Waterloo. His research is focused on inverse problems in heat transfer and spectroscopy applications.