|Abstract in English:|
The Italian countryside is characterized by many small farms, spread in the territory, which
constitute a great potential of renewable energy. However renewable chains require large
investments to ensure economic stability and technical feasibility of the same. The following
study aims to analyze technical and economic feasibility of micro-anaerobic digestion plants
for small farms.
Discontinuous charged digestion, commonly called batch, is characterized by a single
feeding of the organic substrate in the reaction chamber, perfectly sealed, able to make the
anaerobic conditions. The matter is ejected only at the end of fermentation process, when all
the organic potential has been transformed into biogas. This technology is characterized by
simplified features, with the possibility of setting up more digestion chambers, loaded with
different types of biomass typically seasonal, then biogas will be valorized by an energy
conversion system. The Biomass Research Centre, on loan from the Ministry of Agriculture
and Forestry, inside the project ERAARZ (Renewable Energy for Farms derived from Zootechnical
Slurry), is developing in Umbria an innovative batch prototype plant with a nominal
electricity power rating of about 50 kW. Chamber for biomass digestion will be undertaken
using a machine for bagging corn in plastic bags, filled with a mix of different biomasses and
zoo-technical slurry. The anaerobic processes activation will be improved through slurry
spreading by valves at the top of the chamber. An hydraulic pump recycles at the top the slurry,
after its heating made by heat produced into the energy conversion system, ensure the optimal
conditions for bacterial growth inside the bio-cell.
Continuous monitoring of biogas will enable data collection that will be used to reach for
the better working conditions and better system performance.
This plant, thanks to the lack of mechanization and push for lower costs, can be a solution also
for developing countries.