Techniques for measuring flare combustion efficiency and destruction removal efficiency: A review

Growing awareness of the environmental and health impacts of unburned and partially pyrolyzed hydrocarbons emitted by flaring establishes a need for instrumentation that can quantify the performance of flares in terms of overall combustion efficiency (CE) as well as the destruction removal efficiency (DRE) of a particular species. Climate modelers and policymakers need CE estimates to calculate the overall contribution of flaring to global methane inventories, so they may understand how flare emissions impact climate change and develop science-informed regulations; regulators need tools for enforcing current and emerging rules governing flare DRE; flare operators need instrumentation to identify problematic operating conditions in real time; and combustion equipment manufacturers need to quantify improvements in CE/DRE realized through new flare tip designs. This paper reviews the current state-of-the-art in instrumentation and techniques used for quantifying CE and DRE, with a focus on flaring in the oil and gas sector. The paper begins with an overview of flaring, followed by a discussion of the aspects of flaring that make this measurement so difficult to carry out. Techniques for measuring flare CE and DRE are then examined. The paper concludes with an outlook of future challenges and opportunities. • Growing need to measure flare combustion efficiency and destruction removal efficiency. • Measuring CE and DRE is difficult due to spatial heterogeneity and temporal variation. • Uncertainty in CE/DRE estimates is poorly understood. • Review of near field and far field extractive techniques, remote-sensing techniques. • Outlook for emerging technologies, analytical research, and future research avenues.