Abstract
In years to come, water and energy are two issues of concern for trying to keep a continued and sustainable existence of mankind on earth. Regarding the generation and reliable supply of energy; it is a vital matter, especially for those marginal and inaccessible rural communities, which continually struggle for energy as constantly it is in short supply and their only energy sources at hand are crops and forest biomass. When there is abundant availability of vegetative biomass and crop residues, consequently processing them for biogas generation is a great opportunity for energy diversification which will allow for having a sustainable and readily access to other available energy sources. The objective of this work was to undertake a conceptual engineering design for a portable biodigester by using sheep manure, whereas its performance is modeled for evaluating its descentral operation, especially when it has to handle a previously treated high dry matter substrate. Simultaneously, it has to reduce as much as possible the energy utilized for transporting the residues and the biofertilizer cake, by carefully planning the location for feedstock loading and biofertilizer unloading sites. The biodigester consists of a cylinder with an effective operating capacity of 10 m3, where a substrate with 39% of total solids is poured, having a retention time of 30 days, and bearing in mind that it should operate within the thermophilic range which is controlled by the container thermal insulation and warm water heated by solar energy. During the simulation performance trials for the biodigester running with residues to generate biogas, the energy balance for the descentral scheme was more efficient as it got an energy saving of 50% when it was compared to a centralized functioning mode.
