Technical Evaluation of Mechanised Harvesting of Field-stacked Vineyard Pruning and Subsequent Pretreatment for Solid Biofuel Production

This study assesses the mechanised collection of vineyards pruning residues as a low-cost biomass feedstock for advanced gasification within the CBE4I project (Clean Bioenergy for Industry). It presents the results of a field-piled vineyard pruning residues collection trial using a tractor-mounted López-Garrido TBA 2300 harvester-mulcher, with pneumatic biomass transfer to a 5 m³ front container. The performance of the collection system was satisfactory, achieving results comparable to those obtained with other commercially available machines: weight productivity of 1.47 tWM/PMH (0.85 tDM/PMH) and 0.22 tWM/ha (0.12 tDM/ha). To obtain solid biofuels the biomass was shredded using a 30 mm mesh and subsequently sieved through a 2 mm screen to reduce the fine content. The pretreatment results were 14.09 kgDM/h kW of specific mass flow and 13.56 kWh/tDM of specific energy for the shredding process. The energy consumption of the sieving process was 1.6 kWh/tDM with the mass flow rate being 43% lower than that of the shredder. The biofuels obtained fulfilled the characteristics required for the gasification tests of CBE4I project (particle size class P45, moisture content below 20%, bulk density > 200 kg/m3, and ash content below 6%).