Remote helicopter-borne detector for searching of methane leaks

Designing a reliable leak bio-detection system for natural gas pipelines

“…The available methane detection methodologies [40, that obey the device specification criteria mentioned previously, are presented in Table 4. A pre-selection stage reduced the alternatives to nine, namely: continuous-wave cavity ringdown (CW-CRD) sensor [69], A1; the near infrared optical probe (NIR-S) [67], A2; the continuous auto gas chromatography (GC) system [72], A3; the tunable diode laser spectroscopy (TDLS) unit [75], A4; the photoacoustic laser spectrometer (PLS) [79], A5; the photoacoustic (PA) sensor [82], A6; the InGaAsP distributed feedback diode laser detector (NIR) [86], A7; the continuous wave, external cavity tunable diode laser (CRD) system [97], A8; the bacterial sensor (microscale) [99], A9. An expert panel set grades to the cri- Fig.…”

“…Alternatives A3 (GC system) and A9 (microscale sensor) do not provide the required sensitivity (criterion f 3 ) and response time (criterion f 7 ), at reasonable cost [72,99]. The tunable diode laser spectroscopy system (alternative A4) offers substantial benefits on production scale that, in the near future, are expected to generate a lowered energy consumption device and less maintenance of equipment [75]. The cost of these systems, however, is still relatively high and their application is usually limited to situations where an integrated measurement of methane gas density over relatively long open path lengths is required [122]; consequently, the system is typically used to measure the presence of clouds of gas within lengths of the order of meters.…”