ABSTRACT
Biogas produced by anaerobic decomposition of organic materials at wastewater treatment plants or waste disposal sites is generally burned in internal combustion engines of cogeneration units. Biogas contains besides main components like methane (typical concentration 50-65% vol.) and carbon dioxide (concentration of 30% vol.) also components which often complicate its following using. Such components are first of all low molecular siloxanes. Siloxanes are family of man-made organic compounds that contain silicon, oxygen and methyl groups. Siloxanes are used in the households in make-ups for personal hygiene, health care and in industrial products. As a consequence of their widespread use, siloxanes are found in wastewater and in solid waste deposited in landfill. At wastewater treatment plants and landfills, low molecular weight siloxanes volatilize into digester gas and landfill gas. When this gas is combusted to generate power in internal combustion engines of cogeneration units, siloxanes from biogas are oxidated into silicium dioxide, whose deposits on the walls of cylinders have a negative effect on the service life of internal combustion engines.
