Methane sensor to lift coal mine safety

Researchers from Princeton University and the United States Naval Research Laboratory in Washington DC have created a gas sensor that can detect methane gas in mining operations at a reduced cost.

Laser-based sensors are the current standard for methane detection but are an expensive investment for miners.

This is particularly important in coal mining environments, which require stringent methane checks to avoid any potential accidents or explosions.

The researchers, instead, used an interband cascade (IC) light emitting device ICLED sensor, which could detect methane concentrations as low as 0.1 parts per million.

ICLED is a type of LED that produces light at mid-infrared wavelengths to measure chemicals.

The sensor measures infrared light transmitted through clean air without methane, and compares it with air containing methane.

A metre-long hollow-core fibre that contains an air sample was added to improve the sensor’s sensitivity.

“This level of precision is sufficient to monitor emissions near sources of methane pollution,” one of the authors of the research paper, Nathan Li, said.

“An array of these sensors could be installed to measure methane emissions at large facilities, allowing operators to affordably and quickly detect leaks and mitigate them.”

Li added that the technology could hold the key to a lower cost alternative for methane detection.

United States Naval Research Laboratory physicist Jerry Meyer said that the ICLEDs developed in the study had the potential to be mass produced, and emit 10 times more power than commercially available infrared LEDs.

“This could enable ICLED-based sensors that cost less than $US100 ($129) per sensor,” Meyer said.

The research was published in the Optical Society journal Optics Express.

The researchers are now aiming to increase the mechanical stability of the hollow-core fiber and how changes in temperature and humidity may affect the system.

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