2.1. Biogas
Biogas used in the experiment was obtained from a continuously
stirred reactor located at Energy Research and Development Institute,
Chiang Mai University, Chiang Mai, Thailand. It was stored in
a closed, collapsible rubber dome from where it was fed to an engine
intake port at a pressure of 40 Pa. The biogas was regularly sampled
and analysed for its properties and composition. The properties of
the biogas used were found to remain nearly unchanged during
the course of experimental test run. With average relative humidity
of 84% and methane content of 72% by volume, lower heating value
of the biogas was estimated to be 22.9 MJ/m3.