Multifractional Analysis of Waste Biomass from Grape (Vitis vinifera L.) Cultivation and Processing for Thermochemical Parameters and Emission Factors

The development of viticulture is associated with the production of significant amounts of plant residues (leaves, shoots, pedicels, and grape pomace). This study evaluated the thermochemical, elemental, emission and stoichiometric properties of material from four grape cultivars (Chardonnay, Merlot, Riesling, Zweigelt) grown in Lednice (Czech Republic). Significant differences were observed for all analyzed characteristics. Grape pomace exhibited the highest heating value (HHV: 17.95 MJ kg−1, LHV: 15.95 MJ kg−1) and was characterized by high carbon (42.66%), nitrogen (2.05%) and sulphur (0.37%) content. Pomace also showed the highest emissions of SO2 (0.73 kg·t−1) and NOx (7.22 kg·t−1). Leaves contained the highest ash content (10.90%) and showed the highest dust emission factor (13.77 kg·t−1), whereas shoots had the highest volatile matter content (66.47%). Shoots were characterized by a moisture content of 8.94% and the highest oxygen content (49.47%), while exhibiting the lowest ash content (2.29%), nitrogen content (0.75%) and dust emission factor (2.89 kg·t−1). Hierarchical cluster analysis confirmed the greatest similarity between pomace and pedicels, while shoots formed a distinct cluster with different thermochemical characteristics. The results indicate that although all grapevine waste fractions constitute a potential bioenergy feedstocks, their diverse emission and stoichiometric profiles require individual adjustment of combustion process parameters.