Análise de sistemas de secagem de café utilizando-se bomba de calor e gás liqüefeito de petróleo - GLP

• Autor(a) principal: Santos, Reginaldo Rodrigues dos
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/622
• topic: Secador de café; Custos de secagem; Gerador de calor; Coffee dryer; Drying costs; Heat generator; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::ENERGIZACAO RURAL

This work aimed to analyze cherry coffee drying after wet removal of skin and mucilage in an intermittent concurrent flow batch dryer using a heat pump to condition the drying air. To evaluate the technical viability and operational cost of this system, a comparative study was carried out using a fixed-bed dryer, using a gas heat generator, liquefied gas of petroleum (LGP), as heat source for the drying air. Drying air temperature was 40 °C in the intermittent concurrent flow batch dryer and during predrying in the fixedbed dryer. For complete drying in the fixed-bed dryer, drying air temperature was 50 °C. Three tests were carried out for each drying system studied. Coffee (Coffea arabica L.) was the product used. As control, an elevated patio under the sun was used with one drying being conducted for each assay until the coffee reached a final moisture content of 11.0 ± 0.5% w.b., to compare the quality of the final product. To evaluate the drying energy efficiency of the systems, fuel and electric energy consumptions were determined. Based on the results obtained, it was possible to observe a lower energy specific consumption in the intermittent concurrent flow batch dryer in all tests, compared to the fixed-bed dryer. Performance coeficient (PCO ) of the heat pump presented 2.3; 2.4 and 2.5 for tests 1, 2 and 3, respectively. The operational cost of the complementary drying per 60 kg bag of processed coffee was R$ 16.00, R$ 15.89 and R$ 18.48 for tests 1, 2 and 3, respectively, for the intermittent concurrent flow batch dryer; and R$ 7.66, R$ 6.44 and R$ 5.57, for tests 1, 2 and 3, respectively, for the fixed-bed dryer. The final quality of the product was not compromised when drying under the two systems was compared with their respective control samples.