During normal plant operations, there are often losses of methane gas from unintentional fugitive leaks, as well as venting during normal operations or during process upsets. Given the high global warming potential of methane, the safety risks involved in the presence of this explosive gas and the direct and indirect effects it can have on human health, there is increasing pressure on operators to reduce these emissions to limit and eventually eliminate them.
Timely detection and active monitoring of methane leaks are critical steps in decreasing major GHG emissions, improving efficiency and avoiding financial losses. Traditionally, companies have relied on leak detection and repair programmes for identifying and plugging methane leaks. Some of the tools that are used to identify these emissions include [1]:
Optical leak imaging:
The use of thermal infrared cameras to provide real-time visualisation of gas leaks. This is particularly useful for identifying fugitive leaks through viewing vents, flanges, and other areas with potential for methane leakage.
Laser leak detectors:
Methane molecules absorb a specific wavelength of the electromagnetic spectrum, and these detectors transmit a laser beam towards a target point and measure the absorption of the beam reflected from that point. It is useful for detecting methane leaks originating from hard-to-reach sources and/or throughout difficult terrain, from distances of up to 30 meters.
Soap bubble screening:
A very cheap method of identifying leaks is by using soapy water. It is effective for locating loose fittings and connections, but not on large openings.
Organic Vapour Analysers (OVAs) and Toxic Vapour Analysers:
These analysers can measure methane concentrations in the area surrounding a leak over a large range.
Acoustic Leak detection:
This can detect high or low frequency signals due to vibration from leaking valves. It is useful for detecting leaking valves when a vent is inaccessible and is particularly effective in detecting larger leaks and pressurised gas.
AIE CONTRIBUTION
AIE has a dedicated service capability and expertise to help operators tackle methane emissions. We have an established desktop approach to methane assessment, and we offer a complete holistic methane management solution to clients through our digital products.
Contact us today to see how to efficiently screen multiple assets using statistical techniques and therefore develop a fully operationalised methane management solution.
REFERENCES:
[1] CCAC Oil and Gas Methane Partnership: Methane Emissions Detection and Measurement Techniques, Equipment and Costs