The absorption spectroscopy of methane in biogas using a near-infrared light-emitting diode

Abstract

Inaba, et al. have performed extensive laboratory studies of unflammable and toxic gases in the atmosphere, using a laser diode (LD) operated below threshold as light-source. The authors of this paper are presently investigating the use of a laser diode operated above threshold in measuring the near-infrared absorption spectrum of methane, a constituent of most explosive and poisonous gases. These measurements seek to achieve higher detection sensitivities for the purpose of environmental monitoring. As an initial part of this study, an InGaAsP laser diode operated below threshold has been used to measure the near-infrared absorption spectrum of methane in biogas generated from animal waste products. In the Philippines, a number of animal farms generate biogas for use as fuel.