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The high heterogeneity of some residual biomasses makes rather difficult their energy use. Their standardisation is going to be a key aspect to get good quality biofuels from those residues. Torrefaction is an interesting process to improve the physical and chemical properties of lignocellulosic biomasses and to achieve standardisation. In the present study torrefaction has been employed on residues and by-products deriving from sunflower production chain, in particular sunflower stalks, husks and oil press cake. The thermal behaviour of these materials has been studied at first by thermogravimetric analysis in order to identify torrefaction temperatures range. Afterwards, different residence time and torrefaction temperatures have been tested in a bench top torrefaction reactor. Analyses of raw and torrefied materials have been carried out to assess the influence of the treatment. As a consequence of torrefaction, the carbon and ash contents increase while the volatilisation range reduces making the material more stable and standardised. Mass yield, energy yield and energy densification reach values of about 60%, 80% and 1.33 for sunflower stalks and 64%, 85% and 1.33 for sunflower oil press cake respectively. As highlighted by the results, torrefaction is more interesting for sunflower stalks than oil cake and husks due to their different original characteristics. Untreated oil press cake and husks, in fact, already show a good high heating value and, for this reason, their torrefaction should be mild to avoid an excessive ash concentration. On the contrary, for sunflower stalks the treatment is more useful and could be more severe. [ABSTRACT FROM AUTHOR]

The agricultural sector and its related production chains are good sources of residual biomass. Olive and vineyard pruning residues are present in high quantities in Italy. The limited bulk and energy densities of these biomass materials affect the harvesting and logistic costs, limiting energy and environmental sustainability. Pelletisation is the most efficient process for increasing bulk and energy densities. This study evaluates the pelletisation process of olive and vineyard prunings, pure, or blended with variable quantities of spruce sawdust. A 15 kW pelletisation system was chosen, in line with production at the farm level. The most important quality parameters of the produced agripellets were analyzed. The results of this investigation suggest that blending could valorize other biomass materials less suitable for pelletisation and reach the pellet quality required by Italian technical standards. The addition of pruning residues to spruce sawdust leads to an improvement in durability. Spruce sawdust pellets have a durability value of 78.4%. Adding 20% of olive prunings (S80O20) increases this value to 92.2, while adding 20% vineyard prunings (S80V20) increases this value up to 90.3. The addition of 20% of pruning residues significantly increased the length and decreased fines. [ABSTRACT FROM AUTHOR]

Phasing out fossil fuels to renewables is currently a global priority due to the climate change threat. Advocacy for biomass use as an energy source requires assessing the quality biomass and ecological impacts of bioenergy supply chains. This study evaluated the quality of biomass residues from orchards and silviculture transported from different Northern and Central Italy locations and the carbon footprint of a biomass power plant. The total greenhouse emissions were calculated based on primary data for 2017 according to the ISO/TS 14067. All the residue samples showed their suitability for biofuel use. Ash content was relatively low on average (3–5% d.m.), except for grapevine residues (18% d.m.). The lower heating value was within the expected range of 15–21 MJ kg−1 for plant species. The average GHG emission from the power plant was 17.4 g CO2 eq./MJ of electrical energy, with the energy conversion (38%) and transportation of biomass (34%) phases being the main impact contributors. For this study, impacts of residual agricultural residue were about half that of residues from forest management, mainly due to chipping and greater transport distance. Results show that sourcing residual biomass materials for electricity generation close to power plants significantly reduce GHG emissions compared to conventional fossil fuels. [ABSTRACT FROM AUTHOR]

Currently the biodiesel chain is promoted by the European energy policy. For the Italian scenario the sunflower is one of the most important crop to be considered for biodiesel production but the chain is not fully profitable. This problem could be solved with the increase of farm incomes through a proper valorization of by-products. From this point of view the oilseed crop is not considered only for oil production but also for producing multiple products with the same economic value. This is the main inspiring concept of the Extravalore project. The sub-project “Raw Materials” investigated about the possible influence of different agro-technics performed in three distinct geographical environments (Northern, Central and Southern Italy) on the characteristics of by-products obtained from sunflower crop. A national net of experimental tests was set during the 2010–2013 period in order to evaluate the adaptability and the potential production of high oleic sunflower hybrids. 7 seed companies supplied the 20 genotypes assessed in total (18 high oleic hybrids and 2 as control), 11 of them were evaluated all the three years. Achene yields of tested high oleic hybrids were extremely variable: from 2.05 t ha −1 to 4.04 t ha −1 in Northern Italy, from 2.50 t ha −1 to 4.24 t ha −1 in Central Italy and from 2.09 t ha −1 to 2.68 t ha −1 in Southern Italy. For this reason, it was necessary a precise characterization of varieties before their cultivation. The cultivar screening showed general difficulty for high oleic hybrids to reach the performances of achene and oil yields of the conventional ones. In particular, LG55.57HO and PR64H31 resulted the best high oleic cultivars for Northern Italy; many of the high oleic tested cultivars performed well for Central Italy and also for Southern Italy but with a higher variability. The highest potential production was registered in Central Italy; Northern Italy gave decreased but similar results, despite the different latitude; in Southern Italy the productions were 20–30% lower, even with the irrigation support. All high oleic tested cultivars showed oleic acid content in lipid fraction always above the 84% in Central Italy, meaning a stability of the character, very important for the biodiesel production. [ABSTRACT FROM AUTHOR]