2016/11/27 by Sandipta Roy, Roy, Sandipta, Desikan, Ramakrishnan +2
Chemistry · Engineering · Environmental Science · #Atmospheric and Environmental Gas Dynamics #FOS: Physical sciences #Gas Sensing Nanomaterials and Sensors #Instrumentation and Detectors (physics.ins-det) #Spectroscopy and Laser Applications
paper · pdf · doi:10.48550/arxiv.1611.08797
openalex publication_date 2016/11/27 · openalex created_date 2022/09/01 · openalex updated_date 2026/07/28
Quantifying spontaneous, fugitive and venting related methane emissions are\noften difficult and cumbersome. However, auditing the methane emissions due to\nconventional and un-conventional hydrocarbon exploitation techniques are\nbecoming necessary. Present generation compact chemical sensors are slower,\ndegrade very fast, and are sensitive broad-spectrum gases. On the other hand,\noptical sensors are very fast in detection of gases and more precise and can be\neasily employed in various environments like boreholes and soils. In this\nstudy, we report development of an optical sensor that is methane specific,\nfast for real time applications and has tremendous application potential in the\nexploration of coal bed methane and other hydrocarbon reserves with methane as\na major constituent. The detection process is based on the principle of\nspectroscopic absorption of light. The detector, NiSi Schottky diode, was\nfabricated and characterized exclusively for the 1.65 um, narrow bandwidth\nmethane absorption. The probe is of 20 cm length and comprises of a laser\nsource and the NiSi detector aligned optically. This probe can be employed in\nboreholes, mine vents and soil layers for measuring real-time fluxes in methane\nconcentrations. From the laboratory based experiments it is observed that the\ndetection limits of the developed device is very low (3% by volume) and the\nresponse time of detection is very rapid (about 2 seconds). Based on the\nmaterials used, fabrication procedures adopted, sensitivity of the device and\nits compactness, the developed sensor can be considered as a novel, economic\ndevice for exploration of coal bed methane.\n