Eficiencia de secadores rotativos com diferentes pontos para o controle da temperatura do café
The present study was undertaken in the Polo de Tecnologia de Post-Colheita de Café (Technology Pole in Coffee Post-Harvest), at the Universidade Federal de Lavras, MG. Its objective was to evaluate technically, economically and qualitatively different points of control of maximum temperature in the mass of coffee, with views to the cost reduction and final quality optimization. About 30.000 liters of coffee, with 55 percent (w.b.) of initial moisture content, were harvested manually on the cloth and soon after fanned, washed and separate in different maturation state. After the separation, the portion formed by the cherry and green coffee was submitted to an initial drying in yard until reaching 33 percent (w.b.) of humidity. Two dryers of 5.000 liters were used, operating concomitantly, for accomplishment of the experiment. In a dryer, the temperature control was made conventionally as used by the farmers, which caracterized by the use of the bimetalic thermometer situated on the dryer cylinder. In the other dryer, the temperature control was performed using a thermocouple situated in the middle of the mass. It was adopted 45°C as the maximum temperature in the coffee mass. The drying performance was evaluated by the following measurements: initial and final moisture content, coffee mass temperature, exhaustion air, drying air and ambient temperature, humidity relative, static pressure in the plenum, speed of the drying air, total time of drying and total consumption of fuel. The economical evaluation was done by calculating the costs of labor, fuel, electric energy, fixed capital depreciation and total cost. The cup proof was curried out using samples with and without the presence of defects. Considering the obtained results it was observed major quality in the coffee with the temperature control with the located thermocouple in the middle of the mass, however, the low temperatures used in this test resulted in smaller efficiency and larger total cost of drying.
| Main Authors: | , , , |
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| Format: | biblioteca |
| Published: |
2003
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| Subjects: | COFFEA ARABICA, PROCESAMIENTO, CALIDAD, EQUIPO, SECADORAS, GASTO ENERGETICO, COMBUSTIBLES, COSTOS, |
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