Methane DRE Measurement via PFTIR Plume Analysis
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Solution Overview
Problem
Existing methods for measuring flare destruction and removal efficiency (DRE) do not specifically account for methane DRE, which is crucial for regulatory compliance and environmental impact assessment, especially with the enactment of the Inflation Reduction Act of 2022.
Innovation Solution
A method using passive Fourier transform infrared (PFTIR) remote sensing to determine the methane DRE of elevated flares by calculating the methane carbon fraction in waste gas streams and the flare plume, and then applying these calculations to determine the methane DRE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If PFTIR instrument is used to measure combustion products, then measurement capability is improved, but measurement precision for methane DRE specifically deteriorates
Solution Approach 1:
The patent segments the measurement process by separating methane-specific detection from general combustion product detection. It uses PFTIR for general combustion product measurement while implementing a distinct methane monitoring subsystem with specific calculation methodology for methane DRE, allowing each measurement type to be optimized independently
Solution Approach 2:
The patent introduces an intermediary calculation layer that processes PFTIR data specifically for methane DRE determination. This intermediary process uses the relationship between methane input, combustion products, and unburned methane to derive methane-specific efficiency metrics from the broader combustion data
2Measurement precision
If physical sampling probes are used to measure DRE, then direct measurement is possible, but measurement difficulty increases due to turbulent flame patterns
Solution Approach 1:
The patent replaces mechanical sampling probes with optical-based PFTIR remote sensing technology. This substitution eliminates the need for physical insertion into turbulent flames, using infrared spectroscopy to measure combustion products from a distance, thereby avoiding the measurement difficulties associated with probe-based methods
3Quantity of substance
If general DRE measurement method is used, then overall combustion efficiency is measured, but specific methane DRE data is lost
Solution Approach 1:
The patent applies local quality by focusing the measurement analysis specifically on methane-related combustion products rather than treating all combustion products uniformly. It calculates methane DRE separately using methane-specific input data and combustion product ratios, preserving methane-specific information that would be lost in general DRE calculations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for accurate measurement of methane DRE, enabling compliance with regulatory standards and providing valuable data for environmental impact assessments.
Implementation Method 1
One such instrument utilizes Passive Fourier transform infrared (PFTIR) and is commonly used to measure flare DRE. The PFTIR instrument works by characterizing a flare plume's chemical make-up. More specifically, the PFTIR instrument measures an amount of energy radiated from the plume from which all species in the plume can be identified and quantified
Implementation Method 2
flares are designed and operated to meet regulatory standards which generally require them to have a flare destruction and removal efficiency (DRE) of at least 98% with the most recent regulations issued in 2024 further affecting the 98% assumed DRE figure. This has largely been achieved by admixing the flammable gas to be discharged and burned, otherwise known as flare gas, with enough air to sufficiently oxidize the gas
Data Source
AI summary
A method and related system, including a processing unit, of determining a methane destruction and removal efficiency (DRE) of an elevated flare receiving at least one waste gas stream and having a flame and a plume. The method includes the steps of: determining a signal strength for each carbon-containing species in the plume using PFTIR sensing over a period of time; measuring a volumetric flow rate for each of the at least one waste gas stream during the period of time; calculating a methane carbon fraction for the at least one waste gas stream using a predetermined gas composition for each of the at least one waste gas stream; calculating a methane carbon fraction for the plume; and calculating the methane DRE using the calculated methane carbon fraction for each of the at least one waste gas stream and the calculated methane carbon fraction for the plume.