In its pure state, it is color less, odorless, tasteless. For safety reason, an odorant is added so that any leak can be easily detected because of typical smell.
The composition of bio gas is never constant. Methane is by far the largest component, its presence accounting for about 95% of the total volume. Methane is a simple hydrocarbon, a substance consisting of carbon & hydrogen. There are many of these compounds each has its own carbon & hydrogen atoms joined together to for a particular hydrocarbon gas as fuel gas. Methane is very light fuel gas. If we increase the number of hydrogen & carbon atoms, we have got progressively heavier gases, releasing more heat, therefore more energy, when ignited.
Specific gravity of methane is .55 which is less than petrol & LPG. This means that biogas will rise if escaping, thus dissipating from the site of a leak. This important characteristic makes biogas safer than other fuels. It does not contain any toxic component; therefore there is no health hazard in handling of fuel.
The air to biogas (stoichiometric) ratio by volume for complete combustion is 9.5:1 to 10:1.
Biogas has a very slow flame velocity, only .290 m/s. at its highest. The range of flammability is 4 to 14% which can give good combustion efficiency.
Biogas has very high octane number approximately 130. By comparison, gasoline is 90 to 94 & alcohol 105 at best. This means that a higher compression ratio engine can be used with biogas than petrol. Hence, cylinder head of the engine is faced so that clearance volume will be reduced & compression ratio can sufficiently increase. Thus volumetric efficiency & power output are increased. Because of its high octane value the detonation occur however high the compression may be. The Boiling point of biogas is above 300 degree Celsius while the calorific value is 35.390 MJ/m3
One of the promising renewable energy sources is biogas, which is compound gas consisting mainly of methane (CH4) and carbon dioxide (CO2). It is normally formed with the decomposition of organic substances. Because of its low energy density, the gas is generally stored in high-pressure gas bomb. To store it in a condition of high density, it is also attempted to store methane in the form of clathrate. The clathration of methane requires normally high pressure and low temperature. If the clathration of biogas and methane could be achieved under the normal pressure and temperature, this would make the gases a very useful energy source. In this study, the clathration of methane under the normal pressure and temperature was first attempted by using Tetrahydrofuran (THF) as additive. Further, to realize the higher storage density of methane, CO2 must be removed beforehand because not only methane but also CO2 form clathrate. To achieve CO2 removal, the possibility of absorption method using Monoethanolamine (MEA) is experimentally investigated, aiming efficient biogas utilization in final.