The presence and proportion of biogas parameters may vary according to different environmental factors such as process and substrates.
The CH4 (methane) is the most important biogas parameter, as it means energy at the end, in forms of electricity or fuel source as biomethane. The CH4 should vary between 45-70% in a normal operation. But the optimum range is 55-65%. The methanogens like the presence of high methane. Also the high methane means the dominant and strong anaerobic species are present in the digesters, which ends up with high biogas and energy yield.
the biogas analyzer screenshot
Commonly found impurities and problems are given in the table below.
| Compound | Content | Effect |
| CO2 | 25-50% | – It reduces calorific value.– If the gas is wet it causes corrosion. |
| H2S | 0-0,05% | – It has an abrassive effect on equipments and piping systems. – SO2 emissions occur after combustion or H2S emissions occur as a result of incomplete combustion.(The limit value should be 0.1%). |
| NH3 | 0-0,05% | – NOx emissions resulting from combustion damage the fuel cells. |
| Vapour | 1-5% | – It has an abrassive effect on equipments and piping systems.– It causes freezing risk in piping systems and nozzles. |
| Dust | >5 µm | – It clogs nozzles and fuel cells. |
| N2 | 0-5% | – It reduces calorific value. |
| Siloxane | 0-50 mgm-3 | – It hurts and corrodes engine systems. |