RESEARCHES ON THE DIGESTERS AND REACTORS WHICH CAN BE USED IN A FARM SCALE BIOGAS PLANT

In the general context of searching integrated system of renewable energy production, this paper present some researches on the reactors and the digesters, as a main part of a biogas plant at a farm scale. After we present the most used types of digesters, we also concentrated over the processes which take place into a digester, one of them being the removal of H2S from biogas (desulphurisation), which can be made by various methods, either biological or chemical, taking place inside or outside the digester. In the case of biological desulphurization outside the digester, we concentrate on the types of reactors which can be used in this case. Beside the well known types of reactors, we present the possibility of using an original self pressure membrane bioreactor. In this type of bioreactor, the metabolic activity of gas producing microorganisms, especially yeast, could obtain high pressure from gas produced in closed medium on the one hand, and separation of other products of metabolism through membrane on the other hand, using gas pressure as driving force. It is known that several strains of yeast resist on very high hydrostatic pressure heaving good activity. This fact give the possibility to use their energy for other purposes, such as producing mechanical work. Combination of both, gas pressure and alchool burning, increase the process efficiency.