Obiettivo In Europe, household waste represents 110 million tons a year. the processing of the biodegradable waste - about 60% of the total waste - by anaerobic digestion (or methanization) makes an interesting alternative for conventional processing as it allows on the one hand to produce energy (in biogas form), and on the other to recuperate biologically stabilized organic matter recyclable in agriculture.The Valorga anaerobic digestion process has the characteristic of being specifically adapted to solid organic waste processing : fermentation takes place in a high solids medium, on the one hand allowing the volume of the manipulated and heated matter to be decreased, and on the other to decrease the reactor volumes needed for processing. This requires a specific adaptation of all equipment in order to optimize running and maintenance on an industrial scale.The aim of the project is to demonstrate the technically-economical feasability of this treatment.In May 96, the plant was processing 72000 tons per year of MSW. The average performance were as follows :INPUT : raw household waste 72000 tOUTPUT : scrap metals 2500 t glass 6500 t combustible waste 20400 t biogas 7,9 million Nm{3} = 10200 t soil organic conditioner 37200 tThe lack in inputs corresponds to steam and water addition during the processing.The gross energy production is 3680 TOE/Y. Self consumption and losses of biogas represents 10% of the total biogas. Energy is sold in high pressure steam.The soil organic conditioner presents the inherent quality for this type of waste, when there is no sorting at source.The revenue from energy and other products sale is about 6 millions FF/Y.The operating costs are calculated as fixed charges plus proportional charges. The cost is decreased from the money savings other than energy : in the case of the project, it means getting rid of the dumping costs. The running costs in Amiens today on a total of about 6 millions FF/Y.In 1996, a 4th digester was built and started in June 1996 so as to increase the processing capacity of the factory to 100000t/y.In order to optimize the quality of the compost, modifications on the sorting line have been envisaged, as well as the setting up of a selective collection of the organic parts of the waste.This demonstration project is located at Amiens.The plant has a treatment capacity of 72000 tons per year of municipal solid waste collected in bulk.The first step is a mechanical sorting to remove most of the non-biodegardables components (metal, glass, plastics). Then the sorted waste is digested in three 2400 m{3} reactors.The characteristics of the Valorga methanization process are as follows :- it is a single step process : all the biological reactions take place in the same volume.- the dry matter content in the reactor is high (30%) : besides the technically-economical advantages on the volumes, it avoids any setting of heavy particles which have not been removed by sorting.- the digesters are vertically cylindrical : their height allows matter extraction through simple gravity- it is a plug-flow type process : even though the reactor is cylindrical, the path of the matter is a lateral plug-flow type. In fact, a vertical median wall, on 2/3' ds of the diameter of the reactor, separates the passages, situated at the base of the reactor, when introducing and extracting the matter. This wall forces the matter to carry out a circular path to by-pass it.- stirring system is pneumatic.The stirring principle of fermenting matter is to inject biogas under pressure at the bottom of the reactor, using a network of injectors. The injectors are grouped together in different parts spread out along the surface of the reactor. The biogas is stocked in a non-rigid tank, compressed by a two levelled compressor cooled down by an aerorefrigerated group, stocked in a box, and released successively in short impulsions in the different sectors.The stirring sequences are entirely automated. The biogas used for stirring is within a closed circuit.- an important characteristic is the complete absence of any mechanical part inside the reactor.The cost of processing organic waste by anaerobic digestion now competes with other forms of processing. Programma(i) ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985 Argomento(i) 1.3 - PRODUCTION AND USE OF BIOGAS Invito a presentare proposte Data not available Meccanismo di finanziamento DEM - Demonstration contracts Coordinatore VALORGA SA Contributo UE Nessun dato Indirizzo RUE DE MASSACAN 5 BP 56 34740 Vendargues Francia Mostra sulla mappa Costo totale Nessun dato
