Beschreibung:
Many municipalities are turning to landfill biogas to generate electricity. A major challenge is the presence of volatile cyclic organic siloxanes in the biogas stream, which upon combustion form silica deposits, decreasing the lifetime and warranty of reciprocating engines and turbines. With literature reporting that the analysis of biogas for siloxanes is complex, an investigation was completed to identify best practices for measuring siloxane concentrations in the biogas. The result is an easy-to-use collection and analytical technique that used commercially available XAD-2 resin ORBO® tubes to capture siloxanes through sorption. Following desorption, analysis was done on a gas chromatograph equipped with a flame ionization detector. Using the developed technique at the Region of Waterloo landfill, the sampled biogas showed the presence of D4-siloxane at an average concentration of 37.6 ± 1.7 mg/m3, while the D5-siloxane concentration was 21.9 ± 1.2 mg/m3. These measured concentrations were higher than those reported by an accredited lab. Investigation suggests that the use of Tedlar® bags by the outside lab to collect the biogas sample affected the reliability and variability of the latter approach.