[max2]

Hi, I'm doing a biogas efficiency calculation using the Indirect Method for boilers. In order to calculate the Theoretical Air Requirement in the  biogas boiler, I need some information on the percentage of Hydrogen, Carbon, Oxygen and Sulphur. Does anyone know the percentages of carbon, hydrogen, oxygen and sulphur in Biogas?

[Hunter2]

This depends where the source of biogas comes from. Mainly it is methane gas what is developed. Depending what the animals has eaten of course also others.

[Enthalpy]

And depending on how well the methane has been separated from nitrogen, vapour, dioxide, oxygen, argon...

Maybe the proper approach is to compute the air amount for pure methane, to ensure that no CO is produced in the most demanding condition. The flame will just be a bit less hot with impure gas.

Or is there a risk to find gases needing more air per molecule than methane does? Say, ethane, ethanol...?