No abstract

Pruning residues from olive groves represent an important biomass source. Until now, the management of pruning residue has generally represented a disposal problem rather than an opportunity for additional revenue. The main problem is the lack of a well-organized pruning biomass supply chain. In particular, harvesting is a key stage that influences the product quality, the type of logistics chain, and the economic sustainability of the pruning supply chain. The aim of the present paper was the evaluation of the machine performance of the Facma Comby TR200 towed shredder. The harvesting tests took place in Agios Konstantinos, Fthiotida, Central Greece. Two different experimental fields were used for the evaluation of this harvesting system; these fields were characterized by different slopes to check the convenience of using such a towed shredder on both hilly slopes and flat terrains. Analysis was conducted focusing on both the work productivity and costs. Moreover, an evaluation of the obtained hog fuel quality was performed. The Facma Comby TR200 showed good work performances on both flat (2.60 tdm·h−1) and hilly (2.74 tdm·h−1) land, even if a consistent influence of the pruning biomass yield on the work performances was reported. The biomass quality could be consistently improved by modifying the pick-up systems to avoid the collection of inert materials (soil and rocks). In fact, the analysis showed a high ash content in the comminuted material (4% dry basis). Finally, the economic aspects of this study’s results were in line with those reported in the literature. The applied harvesting system showed a cost equal to 29.88 and 16.59 €·tfm−1 on flat and hilly land, respectively.

The concept of co-pyrolysis of biomass and conventional fossil fuel offers various advantages such as higher liquid product yield and higher char conversion than if the coal and biomass particles were processed individually. In the case of added value fuel production such as diesel and gasoline, the maximization of the fraction of pyrolysis oil is the foremost objective. At the same time, the produced char and permanent gases should be properly used for the isothermal and stable operation of the pyrolysis process. This study presents an integrated model of co-pyrolysis in ASPEN Plus for the production of advanced hydrocarbons aiming to determine the conditions under which the process performance is maximized. The methodology for the design and modeling of each main unit of the system (i.e., the pyrolysis plant, the oil upgrading unit, and char exploitation plant) is described in detail. Simulation runs were performed for various blending ratios from 0% to 100% of coal to biomass, aiming for the optimum design and operation scheme regarding (a) maximization of the yields of the desired products and (b) exploitation of the retrieved char. Simulation results revealed that high yields of hydrocarbons (up to 0.179 kgHCs/kgfeed) can be produced due to the synergetic effects of co-pyrolysis of coal and biomass. Moreover, the total process efficiency when the rest of char is utilized for electricity and methanol production can reach at 55.5% and 61.9%, respectively. Finally, the energy balance calculations for the case of 60% coal blending ratio showed that almost 30% of the initial heat input is used as heat for pyrolysis and allothermal gasification of the char. Possible use of alternative heat sources, e.g., from solar energy for these two processes would further improve the system performance in terms of advanced fuels productivity.