The role of biomass for increasing renewable energy sources mix is considered fundamental, despite some negative environmental impact of first-generation biofuels. The use of biomass obtained in a more sustainable way, as represented by agricultural wastes, should be favoured. The Mediterranean area and Italy in particular offer a large amount of vineyard pruning residues that can be converted into bioenergy. Since vineyards are exposed to treatments based on copper (Cu) and zinc, these metals last in wood residues during pruning and accumulate in the soil. In this study an evaluation of the concentrations of copper and other heavy metals in grapevine pruning wastes, when treated with common plant protection products, was carried out. The study was also extended to the soil, being potentially mixed to the biomass in the case of mechanical collection of pruning residues. The grapevine residues free of impurities that were collected during this study have typical values of copper in pruning wood, varying from 8.5 mg kg -1 when treated with low Cu product, to 19.2 mg kg -1 when treated with high Cu product. It was observed that contaminations during pruning with soil could increase the amount of copper in the residues. More in detail, every percentage point of soil that winds up on pruning residues involves an increase of 1 mg of Cu every kg of biomass. For this reason, we recommend the use of appropriate systems for the harvest of grapevine residues, particularly mechanical systems that avoid soil lifting. Moreover, we suggest the use of pruning residues preferably in large-scale power plants with appropriate emission filters instead of small-scale domestic boilers.
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.
The impact of heat production from vineyard pruning pellets has been evaluated in this paper. The study considers two different systems: the first one based on a mobile pelletizer (PS1) and the second one based on a stationary pellet plant (PS2). The analysis conducted is from “cradle to grave”; the systems under analysis includes pruning harvesting, transport to storage area, pelletization (mobile system or stationary production plant), transport to consumer and combustion. The functional unit selected is 1 MJ of thermal energy produced. The impact assessment calculation methods selected are Eco-Indicator 99 (H) LCA Food V2.103/Europe EI 99 H/A with a midpoint and endpoint approach, and ReCiPe Midpoint (H) V1.10. Considering Life Cycle Assessment results, Eco-indicator shows a total impact of 4.25 and 4.07 mPt for mobile pelletizer and stationary pellet plant, respectively. Considering the three damage categories, PS1 has values of 2.4% (Human Health), 3.8% (Ecosystem Quality) and 17.3% (Resources), more impactful than PS2. Contribution analysis shows that direct emissions are the major damage contributor, followed by wood ash management. From a comparison between the baseline scenario and a scenario with an avoided product (wood ash as a standard potassium fertilizer), PS1 and PS2 with an avoided product approach are 41% and 40% less impactful than in the baseline scenarios. When testing the impact of mobile pelletizer while considering transportation as a factor, a reduction of distance for pellet has been evaluated. Reducing the distance from 100 to 10 km, the total impact of PS1 almost reaches the impact of PS2 with a difference of around 4.6% (Eco-indicator 99 method). The most impactful processes are pellet production, direct emissions and ash management, while a less impactful factor is the electricity consumption. Transportation shows the lowest impact. Considering the ReCiPe impact calculation method with a midpoint approach, the results confirm what was found with Eco-indicator 99; the PS1 shows a slightly higher impact than PS2.
In the latex production chain, rubber tree seeds (Hevea brasiliensis) represent an underutilized fraction with high potentialities, which can increase the sustainability of the whole process if rightly valorized. In the present study, the quality of all the fractions obtained from the rubber fruit were evaluated, with the aim to identify possible applications for their valorization with a circular economy perspective. Seeds from five different varieties of rubber tree were analyzed. Furthermore, a whole mass and energy balance was defined, which has allowed us to define hypothetical production scenarios. The obtained results show negligible differences among varieties. Shells and capsules have shown a composition similar to woody biomass, with high heating values (more than 16.5 MJ kg−1), low nitrogen content (below 0.5% on weight basis (w/w)) and reduced ash content (0.51% w/w and 1.90% w/w, respectively). Kernels were chemically extracted comparing two different solvents: n-hexane and ethanol. Both solvents showed similar extraction yields, i.e., 49% w/w and 46% w/w for n-hexane and ethanol, respectively. The resulting extraction flour was characterized by a high protein content (around 40% w/w) making it suitable for animal feeding. The rubber seed oil could be used in blends of different vegetable oils for biodiesel production. All this information is useful for improving the sustainability of the latex production chain and to assess the sustainability of possible bioenergy value chains.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.