After much research and development, gas sensing specialists Trolex has launched a new methane recovery monitoring system that is set to revolutionize the efficient collection of methane for gas-to-energy projects, carbon trading projects, and safety monitoring.

The new Sentinel system from Trolex is the first system of its type that is certified for use underground and the first to be able to differentiate between methane and other non-methane hydrocarbons and so accurately measure methane content. It does this from the sample gas on a continuous basis and uses infrared detection coupled with other special processes. It uses an initial gas analysis to ‘train’ the system and subsequent analysis can be used for further fine-tuning. The contributions to the overall signal from the methane gas detector caused by methane and other hydrocarbon gases are evaluated and the methane content is derived from the overall signal and the individual contributions from the different gases. This technique provides a continuous online, high-accuracy monitoring capability for methane drainage.

This extremely accurate new system for methane recovery monitoring is a huge step forward in addressing methane recovery, either as a stand-alone gas-to-energy project or as part of the Clean Development Mechanism (CDM) and the Joint Initiative (JI) flexible mechanisms agreed under the Kyoto Protocol. It is a fully integrated system with the advantages of maximizing safety, meeting legal and regulatory requirements as well as generating new revenue streams, all in parallel.

POWER GENERATION and manufacturing uses such as feedstock for carbon black, methanol, and dimethyl ether production. For the very low concentration of methane in mine ventilation air, technological development has progressed to the point that this methane source can be oxidized and the resulting thermal energy used to produce heat, electricity, and refrigeration.

In most cases, the Sentinel systems will be bespoke and precision-engineered to meet the needs of an individual project in order to maximize performance. Long-term system integrity is also ensured by dedicated support for initial installation and ongoing service.

As part of the development program, the Sentinel system technology has been installed in two coal mines in the UK and one in China and is being effectively used in a gold mine in South Africa. Most schemes are either approved or registered with the UNFCCC Clean Development Mechanism (CDM) for gas-to-energy generation, and the system has been proven in dynamic testing conditions by independent authorities.

The Trolex Sentinel system overcomes the limitations of current methane monitoring systems which use either thermal conductivity or infrared detectors. Thermal conductivity detectors measure the thermal conductivity of the whole gas sample, giving a collective reading for all the constituents of the gas, not just methane, and are therefore unreliable. Infra-red detection specifically looks for carbon-hydrogen bonds in hydrocarbon which provides an ideal means of measuring the methane content. Unfortunately, any other hydrocarbon components within the sample will also contribute to the response in an infrared detector. Gas chromatography is also used to analyze coal mine methane sample gas streams, periodically measuring individual amounts of each component gas. Because samples have to be collected from the gas stream and sent to a laboratory for analysis, and the results then have to be sent back to the site, this clearly takes too much time and is far from a continuous measurement process.

Further information on the new Sentinel methane monitoring technology is available from Trolex Ltd, Newby Road, Hazel Grove, Stockport, Cheshire SK7 5DY, by telephone at 0161-483-1435, email: or by visiting the company’s dedicated website

Trolex Ltd
Newby Road
Hazel Grove
telephone 0161 483 1435