Valorizzazione di biomasse residuali del settore agricolo
Creators: name: Alfano, Vincenzo
Publisher: name: Zenodo
Year: 2020
Subjects: bioenergy

description: The doctoral research was performed into a context characterized by the awareness of the need to adopt circular economy models, based on the re-use of residues and by-products replacing non-renewable fossil resources. Availability assessment of agricultural residues currently not used introduces the experimental tests performed on mechanized collection systems for selected residues, such as pruning, end-of-cycle stumps and threshing residues. The aim of the thesis was to evaluate the most innovative mechanical solutions able to overcome the obstacles linked to the collection and logistics. The harvesting and logistics of agricultural residues are the most expensive phases of a supply chain, both for energy and for biorefinery purposes. In fact, these types of biomass are characterized by low density and dispersion in the territory. The thesis is structured in an introductory part, which describes the activities carried out during the doctorate, and a second part with the publications originated from such activities and submitted in international journals and in conference proceedings attached in the second part. The first chapter describes the activity and the aims of the doctoral project. The second chapter is dedicated to the analysis of the potential of agricultural residues in Italy with a focus on a new estimation methodology developed for pruning. The two following chapters describe, respectively, the mechanical and logistic solutions aimed at recovering and transporting prunings and threshing residues. Concerning the prunings, a review of the machines currently available for their collection is presented, such as the experimental activity aimed at the technical-economic evaluation of a mobile system for pelleting of vineyard pruning. In addition to pruning, the enormous potential of vineyards and orchards roots at the end of the life cycle is highlighted. An innovative root extractor able to reduce working times ensuring adequate root cleaning has been described. Among the threshing residues the attention was placed on corn cobs and cereal chaff. The growing interest in these resources, for energy and zootechnical purposes, has led several agro-mechanical companies to develop devices applicable to the combine harvesters for a contextual or subsequent recovery. Concerning corn cobs, a mechanical solution designed by an Italian company able to perform the recovery of the cobs at the same time as threshing, without affecting the collection performance, was evaluated. As regards the cereal chaff, the state of the art of mechanical solutions in correlation to the recovery purposes, including the reduction of weed seeds, has been presented. Moreover, the test conducted in two successive harvesting seasons using a technology developed by a French company able to carry out the collection of the chaff separately or together with the straw is described in detail. Finally, a technical-economic evaluation aimed at identifying the threshold distance from the storage centre, from which it is more economically convenient to gather the wheat and corn residues in bales instead of using a self-loading wagon.