Measuring Biogas Composition with a Compact Microelectromechanical System‐Based Spectrometer

Abstract

To operate a demand‐driven anaerobic digester, improvements to monitoring of process parameters are necessary. Therefore, a mid‐infrared spectroscopic gas sensor utilizing a microelectromechanical system‐based Fabry‐Pérot interferometer was tested for its suitability to measure the biogas concentration online. The spectral data is analyzed using principle component regression to make predictions of methane and carbon dioxide. Testing was performed in a laboratory, at a 1000‐L pilot‐scale digester, and at a 1.2‐MW landfill site. Scans took under eight minutes during testing and it is expected that this can be reduced further to give a shorter delay from the online measurements.