Analysis of the characteristics of the residues of the wine production chain finalized to their industrial and energy recovery

In Italy 1.5 Tg dry matter of residues are estimated to be produced by the agri-food sector. Approximately 30% of them are represented by residues of wine industry sector: grape marc. Referring to its production, it is possible to evaluate about 10 Mg of grapes from each vineyard hectare that generate, as wine industry residue, 2.7 Mg of grape marc, corresponding to about 19 GJ in terms of energy content. This kind of biomass is heterogenous and composed of stalks, grape skins and seeds. In this paper, in order to investigate the possibility of an energy and industrial utilization, the physical-chemical characteristics of each single component of grape marc are examined. In addition, a mechanical extraction test on the seed was performed to evaluate the vegetable oil production and the characteristics of the cake. Results on grape marc components put in evidence some difference in terms of ash and chemical elements content, which represent, specifically for these materials, the most critical aspects to take into account in combustion heating systems.