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Advances in Silage Harvest Operations
Published in Guangnan Chen, Advances in Agricultural Machinery and Technologies, 2018
C. Amiama, J. Bueno, J. M. Pereira
Traditionally, this process was carried out by two differentiated machines: a round baler and a wrapping machine. The forage is collected with a pick-up, at the front, it is introduced into a chamber where it is subjected to compression forming a cylindrical bale 1 to 2 m in diameter times 1.2 m in width. There are three ways of carrying out the compression: in a fixed chamber, in a variable chamber, or in a semi-variable fixed chamber. The fixed chambers use rollers to apply pressure on the forage from the exterior edge of the cylinder, whereby the central part of the bale is less compressed, which may cause fermentation problems if air is left in the center. The variable chambers use belts, and manage to compress the whole forage material to the same pressure although their complexity makes them more prone to breakdowns. The semi-variable fixed chambers are the latest system to be introduced on the market, in an attempt to combine the robustness of the fixed systems with the quality of compression in the variables. The first part of the filling is carried out in a small fixed chamber which, once full, increases in diameter like a variable chamber. Once the bale is formed, a tying mechanism using string or net wraps the bale to maintain its cohesion when it is deposited on the ground.
Processing Solid Wastes and Recyclable Materials
Published in Charles R. Rhyner, Leander J. Schwartz, Robert B. Wenger, Mary G. Kohrell, Waste Management and Resource Recovery, 2017
Charles R. Rhyner, Leander J. Schwartz, Robert B. Wenger, Mary G. Kohrell
The compaction of materials into bales reduces their volume and increases their density. Many recyclable materials (e.g., aluminum cans, paper, and cardboard) are baled to provide more convenient handling and to reduce transportation costs. A forklift vehicle can be used to load and stack the bales on a truck or railroad car. Unprocessed MSW is sometimes baled prior to landfilling. Baling reduces litter and, because of the higher density, increases the working lifetime of a landfill. Landfills in which MSW is deposited in baled form are sometimes called balefills.
Modelling and optimisation of biomass supply chains: a review
Published in International Journal of Production Research, 2018
Nasim Zandi Atashbar, Nacima Labadie, Christian Prins
Three harvesting modes can be distinguished (Sambra, Sørensen, and Kristensen 2008).Multi-pass harvesting is the most common procedure for wheat, corn and rapeseed. Using a combine harvester, the grain is separated and stored in a compartment which is periodically downloaded, while the straw and the chaff (little particles) are released in a line on the ground, called windrow or swath. Then the windrow is picked up by a baler which is towed by a tractor. The baler compresses the biomass to form a bale and once it gets filled, the bale is released.Single-pass harvesting involves a train composed of a combine harvester and a baler. So, grain and straw are harvested at the same time. Compared to multi-pass harvesting, this mode is faster but requires more powerful and expensive equipment. Moreover, it cannot be applied to some crops like rapeseed, whose thick stalks require a few days of passive drying on the windrow.Finally, in whole-crop harvesting, the whole crop is cut without separating its different components. The cereals harvested in this way are used essentially to produce silage (see dry chop in the sequel), to feed cattle or to produce biogas in anaerobic digesters. This procedure is also the rule for herbaceous energy crops like miscanthus and switchgrass.The harvested biomass can be collected and prepared in four ways before being stored for a longer time or transported. The selection of the collection method depends on the desired moisture level and the final use of the product.Baling. Round or rectangular bales of dry biomass can be prepared. The aim is to densify the product to ease storage and transportation (Forsberg 2000). Each kind of bale has its own characteristics. For example, round bales can be stored outdoors because of their ability to shed rain water but their disadvantage is that they are more difficult to handle, transport and store.Loafing. With the help of a loafer or stacker, dry biomass from windrow is compressed to form large stacks with a doom shape which protects the biomass inside from water. The resulting stacks are much bigger than bales but have a lower density.Dry chop. Herbaceous plants with long stalks like miscanthus can be harvested and chopped into small pieces which are blown into a forage wagon which moves in parallel to the harvester. The resulting product can be transferred to a biorefinery or stored as large cones under a farm shed.Wet chop. The process is similar to dry chop but applied to wet crops. In general, the product obtained is carried to a pit to produce silage by fermentation, or to feed anaerobic digesters to generate biogas.