Influência da temperatura, fluxo de ar e altura da camada de grãos na secagem de café (Coffea arabica L.) despolpado em secador experimental de camada fixa
Arquivos
Data
1994
Título da Revista
ISSN da Revista
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Editor
Universidade Federal de Lavras
Resumo
Com o objetivo de avaliar o tempo de secagem e o aspecto do café despolpado utilizando um secador experimental de
camada fixa, foram planejadas e executadas duas séries de ensaios. Na primeira série foi utilizado um fluxo de ar constante de 63 m3.min-1.m-2, sem período de descanso, com revolvimento a cada duas horas de secagem, temperaturas de secagem de 45 e 7OoC e alturas da camada de café de 10, 20, 30 e 40 cm. Observou-se que o tempo de secagem da temperatura de 45oC foi sempre maior que o dobro do tempo de secagem para 7OoC; e que não houve diferença significativa no tempo de secagem entre as diferentes camadas para a temperatura de 7OoC. O café apresentou o seu pior aspecto para a maior temperatura e menor tempo de secagem. Na segunda série foi utilizada temperatura de 7OoC, altura da camada de café de 40cm, revolvimento a cada duas horas de secagem, fluxos de ar de 16 e 63 m3 .min-1 .m-2 e períodos de descanso de O horas (secagem contínua), 2 horas e 4 horas. Foi constatado que o fluxo de ar influenciou o tempo total de secagem e o tempo de secagem no secador, sendo que este tempo no menor fluxo de ar foi sempre maior que o dobro no fluxo de ar maior, em todos os períodos de descanso. O período de descanso não reduziu o tempo de utilização do secador, já que não houve diferença significativa para o tempo de secagem no secador entre os períodos de descanso. O fluxo de ar influenciou o aspecto do café, ou seja, quanto menor o fluxo de ar e maior o tempo de secagem do café, melhor o seu aspecto.
3 -1 -2
Two series of drying experiments were conducted with parchment coffee using a experimental fixed-bed dryer, with the objectives of evaluate the drying time and the quality in terms of aspect. In the first one temperatures of 45 and 7OoC and coffee beds of 10, 20, 30 and 40 cm were used. The air flow rate was 63 m3 . min-1 . m-2 and the coffee was weighed and revolved every two hours. It was observed that the drying time at 45oC was more than twice the drying time for 7OoC. Also there was no significant difference in the drying time among the different layers at 7OoC. The coffee presented its worst aspect for the highest temperature and shorter drying time. In the second experiment a temperature of 7OoC was used with a deepness of coffee bed equal to 40 cm where revolving every two hours during drying with an air flow of 16 and 63 m3 . min-1 . m-2 and resting periods of zero hours (continuous drying), 2 hours and 4 hours. It was confirmed that the air flow influences the total and drying times of drying. The drying time in the low flow rate was twice times higher than the high flow rate, for all the resting period. The resting period did not reduce the dryer utilization time since there was no significant difference in the drying time in the dryer between resting periods. The air flow influenced the coffee aspect, that is, the lower the air flow and the longer the coffee drying time, the better the aspect.
Two series of drying experiments were conducted with parchment coffee using a experimental fixed-bed dryer, with the objectives of evaluate the drying time and the quality in terms of aspect. In the first one temperatures of 45 and 7OoC and coffee beds of 10, 20, 30 and 40 cm were used. The air flow rate was 63 m3 . min-1 . m-2 and the coffee was weighed and revolved every two hours. It was observed that the drying time at 45oC was more than twice the drying time for 7OoC. Also there was no significant difference in the drying time among the different layers at 7OoC. The coffee presented its worst aspect for the highest temperature and shorter drying time. In the second experiment a temperature of 7OoC was used with a deepness of coffee bed equal to 40 cm where revolving every two hours during drying with an air flow of 16 and 63 m3 . min-1 . m-2 and resting periods of zero hours (continuous drying), 2 hours and 4 hours. It was confirmed that the air flow influences the total and drying times of drying. The drying time in the low flow rate was twice times higher than the high flow rate, for all the resting period. The resting period did not reduce the dryer utilization time since there was no significant difference in the drying time in the dryer between resting periods. The air flow influenced the coffee aspect, that is, the lower the air flow and the longer the coffee drying time, the better the aspect.
Descrição
Dissertação de Mestrado defendida na Universidade Federal de Lavras
Palavras-chave
Café despolpado Secagem em camada fixa Desempenho Período de descanso, Parchment Coffee Drying Fixed-bed dryer Performance Resting period
Citação
Guida, Vânia Furtado Assunção Arbex. Influência da temperatura, fluxo de ar e altura da camada de grãos na secagem de café (Coffea arabica L.) despolpado em secador experimental de camada fixa. Lavras : ESAL, 1994. 57p. : il. (Dissertação - mestrado em Ciência dos Alimentos) Orientador: Evódio Ribeiro Vilela