Industrial development and increased energy requirements have led to high consumption of fossil fuels. Thus, environmental pollution has become a profound problem. Every year, a large amount of ...agro-industrial, municipal and forest residues are treated as waste, but they can be recovered and used to produce thermal and electrical energy through biological or thermochemical conversion processes. Among the main types of agro-industrial waste, soluble coffee residues represent a significant quantity all over the world. Silver skin and spent coffee grounds (SCG) are the main residues of the coffee industry. The many organic compounds contained in coffee residues suggest that their recovery and use could be very beneficial. Indeed, thanks to their composition, they can be used in the production of biodiesel, as a source of sugar, as a precursor for the creation of active carbon or as a sorbent for the removal of metals. After a careful evaluation of the possible uses of coffee grounds, the aim of this research was to show a broad characterization of coffee waste for energy purposes through physical and chemical analyses that highlight the most significant quality indexes, the interactions between them and the quantification of their importance. Results identify important tools for the qualification and quantification of the effects of coffee waste properties on energy production processes. They show that (SCG) are an excellent raw material as biomass, with excellent values in terms of calorific value and low ash content, allowing the production of 98% coffee pellets that are highly suitable for use in thermal conversion systems. Combustion tests were also carried out in an 80kW
boiler and the resulting emissions without any type of abatement filter were characterized.
Woody Biomasses (from agriculture and forestry activities) are among the most promising renewable energy sources. Current literature describes woody biomass feedstock supply chains supporting ...biofuels and utilities industries: the potentially productive land area overheads required for biomass production may results in a complex logistic within the whole chain. Its effective enhancement requires significant changes in the logistics environment of energy plants for sustainable energy production and the sequence-dependent procurement chains for biomasses furthermore complicate these changes. According to this, optimizing harvesting and supplying operations turns out to be strategic within the framework of the current energy policy. In this work we present a case study carried out monitoring 57 short rotation forestry (SRF) production sites placed in Emilia Romagna Region, Northern Italy, all supplying the harvested biomass to the same biomass power plant placed in the province of Ravenna (Italy). The overall average yield of these sites was 55 t/ha, the site surfaces ranged from 0.3 to 20 hectares and the distance from the power plant ranged between 8.2 to 102 km with one production site only within 10 km from the power plant. Harvest and transport costs were calculated according to two different harvesting scenarios: i) single phase harvesting (one cutting/chopping machine + tractors and trailers); ii) double phase harvesting (cutting/mowing machine followed after 80 days by chopping machine + tractors and trailers). Results show that, according to the first scenario, at increasing distances overall harvesting and transport costs ranged from 8.9 to 21.0 ± 1.3 /t (average ± standard deviation), while, with reference to the second scenario, they increased from 10.3 to 23.8 ± 1.5 /t with the transportation costs accounting from 16 to almost 70% of the total costs.
Five years old poplar (Populus spp.) plantation represents an interesting model of productivity. The most attractive characteristics of this energy crop are the handling flexibility, the high yield ...of biomass per area unit and the good quality of the chips obtainable. The mechanical harvesting of five-years old poplar plantations requires the use of specialized forest machineries such as harvester, feller, forwarder and chipper. Usually, after felling, the working phases consist of extraction, stacking and chipping. Generally, the last one is carried out in a “static phase”, where the product is taken from staked logs by using a hydraulic arm having a gripper that feed the chipping machine. In order to introduce technological innovations for the medium rotation forestry harvesting, the Consiglio per la Ricerca e la sperimentazione in Agricoltura, Unità di ricerca per l’Ingegneria agraria (CRAING) of Monterotondo (Rome, Italy) has developed a five years poplar cutwindrower and a self-propelled chipper equipped with a pick up system. The prototype of cut-windrower is a semi-trailed machine powered by a 95 kW tractor (at least). It mounts a cutting system and a double pincer with variable positioning. During the cutting phase the plant is grasped by the double pincer which conveys and unloads the stem along the inter-row. The trees are placed parallel to the progress of the tractor, but oriented in the opposite direction. The biomass windrowed is then chipped in a dynamic phase directly from the inter row using the self-propelled chipper equipped with the pick-up head. In the first tests, the cut-windrower has reached an operative working capacity of 0.22 ha h-1, with an operative production of 44 t h-1. On the other hand, the self-propelled chipper has showed an operative working capacity equal to 0.18 ha h-1, and an operative production of 35 t h-1 about. Both machines have shown good quality of the work performed and the results obtained indicates that the work phases could be simplified in order to reduce both the time of use and the harvesting costs.
Giant reed (Arundo donax L.) is a perennial rhizomatous grass that is currently indicated as an alternative crop for bioenergy production. Cultivation of giant reed for energy purposes requires the ...identification of an appropriate propagation technique, usually carried out with stem cuttings and rhizomes. Both methods are very efficient, but also very expensive as they require demanding and labor-intensive manual work. This study aimed at verifying the viability of a mechanical method for in situ rhizome extraction, using a modified stump grinder. Three different machine settings were tested with the goal of obtaining rhizomes with variable length, ranging between 4.4 and 6.4 cm. Survival rate and shoot production were used to determine the vitality of rhizomes with different lengths. The study confirmed the viability of mechanical rhizome production in giant reed nurseries.
In the Italian environments, the rapeseed (Brassica napus L.) is subjected, at ripening, to a seed shattering causing significant losses that reduce the yield and increase the oilseed rape seedbank ...in the soil. Meteorological events and mechanical harvesting are the main factors affecting the extent of seed dispersal. Lacking the availability of works investigating the actual losses during the harvest at large scale, the Consiglio per la sperimentazione e la ricerca in agricoltura, Unità di ricerca per l’ingegneria agraria (CRA-ING) has conducted a study in order to determine the effective seed losses at on-farm scale. The amount of losses of two combine headers, traditional for wheat and specific for oilseed rape harvest, was compared. The rapeseed header had a hydraulic sliding cut-bar and two vertical electric blade on both sides in order to reduce the pulling and tearing action between the cut-off plants and those still standing. The seed losses were evaluated before and during the harvesting by using plastic trays placed on the ground within the crop rows. The trays were arranged in a layout allowing the estimation of the seed losses of three different sectors of the combine headers. The results have demonstrated that, at farm level, the use of a specific oilseed rape header adapted and optimized for the crop requirements allows to obtain a level of seed losses (0,97% of total production), below the values reported in literature. For rapeseed, the higher losses are localized at the final parts of the head, where the plants are strictly intertwined.
PDF
