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Thursday, August 30, 2007

Characteristics of biogas

The Biomass Unit of the CIEMAT Institute of Renewable Energies carried out a thorough study in order to collect as much information as possible on the physical and chemical characteristics of the biogas generated at the landfill site.

The main concern was to have available full preliminary specific information not only on the calorific or energy value of the fuel but also on the presence in the biogas of potentially corrosive compounds that could cause irreparable damage to motors.

Various analyses were carried out in order to determine both calorific value and levels of methane, VOCs (volatile organic compounds), hydrosulphuric acid and water vapour. These compounds are highly corrosive and their presence in substantial concentrations could cause irreparable damage to motors, mainly as a result of the formation of CIH and SH2.

According to the results of the analyses carried out on the main compounds, the methane content is over 50%. This figure confirms the possibility of using the gas as a source of energy, and ensures that the technology envisaged would function properly. It is based on an automatic check of the percentage of methane in the sewer.

The results obtained from the analyses of VOCs and hydrosulphuric acid confirm that the biogas produced may be used without any risk to the energy production equipment. Those compounds which could cause problems by corroding motors are present in small quantities.

However, the analyses also revealed that the biogas is supersaturated with water. This makes it necessary to add a further installation not included in the initial project to eliminate the condensate.

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