Desenvolvimento e avaliação de um secador de fluxos concorrentes, com carga, revolvimento e descarga pneumáticos

• Ano de defesa: 2008
• Autor(a) principal: Melo, Fernanda Augusta de Oliveira
• Orientador(a): Silva, Juarez de Souza e
• Banca de defesa: Monteiro, Paulo Marcos de Barros , Donzeles, Sergio Mauricio Lopes , Melo, Evandro de Castro
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Engenharia Agrícola
• Departamento: Construções rurais e ambiência; Energia na agricultura; Mecanização agrícola; Processamento de produ
• País: BR
• Palavras-chave em Português: Secagem combinada; Transporte pneumático
• Palavras-chave em Inglês: Combined drying; Pneumatic load
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::ENERGIZACAO RURAL
• Link de acesso: http://locus.ufv.br/handle/123456789/641

A concurrent flow dryer with pneumatic load, revolving and discharge, that was compatible with either production and the investment capacity of the small enterprise for drying the pulped coffee was projected, built and evaluated. Because the pneumatic system would be overdimensioned when it would not be moving the product during the drying phase, the fan was also used through a bifurcation to insufflate the hot air in a pre-dryer constructed according to SILVA et al. (2001). Thus, the new dryer was separately evaluated and in a combined system containing both pre-dryer and drying bin. For evaluating the concurrent flow dryer, four tests were accomplished. as being three tests with complete load and one with half load, whereas the air flow was 23.15 m3 min-1 and 33.41 m3 min-1, respectively. For evaluation of the combined drying system composed by the pre-dryer, concurrent flow dryer and storer-dryer bin, four tests were accomplished, from which three were with complete load and one with half load, whereas the air flows of 58.5 m3 min-1 and 64.3 m3 min-1 were respectively used. When operating separately, the prototype showed the values 3,022 and 3,886 kJ kg-1 of evaporated water for specific energy consumption in the tests FT1 and FT2, respectively. Those values are below the consumption limits foreseen in the available literature for this dryer type. In test FT3, however, the average specific energy consumption was 3,856 kJ kg-1 of evaporated water, which was within the consumption limits foreseen in the literature, therefore energetically efficient. When the pneumatic dryer operated with half load (FTM4), the specific energy consumption was 7,041 kJ kg-1 evaporated water, therefore superior to the other tests, as showing to be operable with lower load for which it was dimensioned. In the combined drying system composed by pre-dryer, concurrent flow dryer and storer-dryer bin, the system showed a total specific energy consumption of 4,250; 5,712 and 4,690 kJ kg-1 evaporated water in the tests FD5, FD6 and FD7 respectively, which are below in comparison with some traditional drying processes. When the pre-dryer and the pneumatic dryer operated with half load (FTM4), the total specific energy consumption (6,954 kJ kg-1 evaporated water) was compatible to the other tests, as being energetically efficient. The developed dryer is easily operated during loading, drying and discharge, as well as requires little maintenance and labor, and works efficiently with the coffee amount available. The coffee processed in the new dryer showed good quality concerning to the type and beverage. The combined drying system (hybrid dryer, concurrent pneumatic flow dryer and storer-dryer bin) is a technique that provided a high-qualified product that was also economically viable.