Colheita mecanizada de biomassa florestal para energia

• Autor(a) principal: Canto, Juliana Lorensi do
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/534
• topic: Colheita florestal; Biomassa florestal; Energia de biomassa florestal; Forest harvesting; Forest biomass; Energy from forest biomass; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::MANEJO FLORESTAL

The increasing demand for alternative energy sources, especially renewables, has raised the use of forest biomass as energy. In general, economic development and environmental issues are the main causes of the interest in renewable sources. However, the main barriers to greater use of renewable sources are the economic order. It is considered that one of the most important factors in the use of forest biomass as energy refers to the cost of harvesting and transportation. Therefore, this study aimed to analyze mechanized systems for harvesting forest biomass for energy. The study was divided into three papers. The first paper evaluated the performance and estimated costs of a wood chipping system for comminuting tree tops, which are considered residues from wood harvesting. The system was comprised by a wood chipper, two forest tractors equipped with knuckleboom grapple and one front loader. It was developed in a forest industry in the Para State, located in the North Region of Brazil. System average productivity was 17.51 tonnes per effective hour. The system produced between 94 and 162 times more energy than consumed. Cost per effective hour was R$ 376.56 (US$ 21.51/tonne of chips or R$ 2.70/GJ). The second paper evaluated the performance and estimated costs of two systems for harvesting and baling low diameter forest biomass. One system was a cutter-shredder-baler prototype. The other system required twosuccessive operations, being assessed two mulcher tractors and an agricultural round baler. Machines were evaluated in three different areas on the Osceola National Forest in Florida, Southern Region of the United States. On the most representative site, the prototype recovered 8.05 green tonnes/ha while the mulcher and the agricultural baler recovered 9.75 green tonnes/ha (43 and 52% of available biomass, respectively). The production capacity was 0.30 ha/h for the prototype and 0.51 ha/h for the mulcher-baler system. The systems produced between 36 and 56 times more energy than consumed. Cost was US$ 39.86/t (US$ 3.40/GJ) for the prototype and between US$ 37.60/t and US$ 61.21/t (US$ 3.23/GJ and US$ 5.25/GJ) for the mulcher-baler system. The third paper analyzed a system for harvesting and hogging complete trees. The system was comprised of hydraulic excavator equipped with demolition grapple, bulldozer, front loader, knucleboom loader and wood hog. The study was conducted in an area located at Fort Benning, Georgia State, Southern Region of the United States. Productivity of the complete trees extraction was 579.3 m2/h and of the complete trees hogging was 28.01 t/h. The system produced 35 times more energy than consumed. Cost was US$ 565.14/h (US$ 20.18/t or US$ 2.14/GJ). The choice for a suitable system and the economic feasibility of mechanical harvesting of forest biomass for energy will depend on the local context, the availability of power plants capable of consuming the biomass, the transport distance and other fuels local price.