Coffee beans industrial vibrofluidized bed drying optimization (coffea arabica L.)

Abstract

Drying is one of the most important operations in the co_ee processing industry, which consists of removing moisture content in the grain, from 55% to 10 or 12%. In the present paper, an industrial dryer of vibrofluidized bed of coffee beans (Coffea arabica L.) was optimized, which until the year 2017 presented losses in the drying process about 19% of total coffee beans treated. An analysis of the hydrodynamic and vibrational operation parameters of the dryer was carried out, as well as considerations on the physical properties and drying kinetics of coffee beans. The process operated continuously with a mass flow of coffee beans (ms1) of 3800 kg/h, an initial bed height (Lf) of 5 cm and a total drying time (tT) of 1.3 h. The optimum temperature was 225 °C, which allowed to obtain a light green color, named in the color scale as Pantone 5803C, which denotes a high quality for the type of coffee bean processed in the industry, with a final humidity of 0.131 kg of H2O/kg SS and maintaining a drying speed of 9.6 kg de H2O/m2 h.