Meters for biogas

It is a process of conversion biochemical type that happens in absence of oxygen and it consists in the demolition, owing to micro-organisms, of complex organic substances (lipids, protides, glucides) contained in the vegetables and in the by-products of animal origin, that it produces biogas usually constituted for about 50÷70% from methane and for the remaining part from CO2 and other components. The calorific power of the gas gotten, changes according to the content of methane. A middle value can be set equal to around 23.000 kJ/Nms 3. The produced biogas is treated, accumulated and can be used as fuel for feeding gas boilers joined to turbines for the production of electric energy or in cycle combined stations or internal combustion motors.The by-products of such biochemical process are good fertilizers since part of the azote that would have been able to go lost in the form of ammonia, is in a fixed form now and therefore directly usable from the plants. At the end of the process of fermentation, are preserved integrate the principal nourishing elements (azote, phosphorus, potassium), already present in the raw materials, supporting so the miniralization of the organic azote resulting in such way a good fertilizer. Below, part of the description of the operation of a station is proposed for the purification of the impure waters in a district of 25.000 people."The muds' permanence inside the anaerobic digester last in average around 23 days. While they are inside the tank, the fermentation happens and thanks to the employment of chemical reagents and micro-organisms, the muds are broken up in the molecules simplest possible. The process also produces a big biogas quantity that is canalized in another tank, addressed to the boiler and therefore partly used for maintaining a constant temperature of 33 degrees inside the digester. The quantity in excess of gas, especially in the summer period, is digested through the combustion in the burner set in the center of the square of the station. Annually, it is calculated, this process produces around 300.000 meters cubes of gas, a third part of them are for the time being in excess and they are burnt." (!!? n.d.r.) From the treatment of the impure waters, are also gotten ammonia and nitrates used for the production of fertilizers and organic muds used by firms of mixtures to still get fertilizing substances.