Operational and Environmental Impact of Ashes Produced from Combustion of Vineyard Wastes and their Blends in Fixed and Fluidized Bed Units

The study aimed to provide valuable information for the promotion of vine by-products in fuelling small-to-medium size enterprises near wine/spirit processing industries. The objective was to evaluate and compare the ashes produced from both fixed and fluidized bed combustion of these wastes and their mixtures. Ashes were characterized by mineralogical, chemical, thermal and fusibility analyses and water leaching tests were conducted to remove problematic elements. Slagging/fouling propensities of ashes were determined, and their environmental impact and potential uses were assessed.

The results showed that all ashes were rich in Ca, K, P and Si incorporated mainly in calcite, fairchildite, hydroxyapatite and albite minerals. The fly ash of grape skins was enriched in K and P. Heavy metals showed less preference for fly ashes and all values were below the upper limit for disposal in landfills. The slagging/fouling tendency of grape skins ash was significant; however, no deposition is expected in systems operating below 1000 °C for both fuels and their blend. Water leaching greatly reduced the slagging/fouling potential of ashes. Fixed bed or fly ashes could be used as secondary building materials or for road construction. Those of grape skins could also be used for soil amendment.

Keywords: Ashes; Vineyard wastes; Fixed bed; Fluidized bed