Drying of spent coffee grounds in a cyclonic dryer

Jefferson Luiz Gomes Corrêa, Johnson Clay Pereira Santos, Bruno Elyezer Fonseca, Ana Gabriela da Silva Carvalho


Spent coffee grounds is a byproduct from the soluble coffee company. Besides its use as animal feed or lipid source, it presents a high potential as biofuel. Whatever the application, to be useful, the product has to loose great part of its moisture content. The drying of spent coffee grounds in a cyclonic dryer was studied in the present work. Based on a experimental design, the effects of temperature of the air (Ta) (59 to 271 ºC) and of the ratio mass flow rate of spent coffee grounds to mass flow rate of air (Wc/Wa) (0.1 to 3.6) on the moisture reduction (Mr) and average residence time of the particles on the cyclonic dryer (APRT) were studied. It was observed an inverse relation between Mr and the ratio Wc/Wa and a direct relation between Mr and Ta. Regarding the APRT, it presented an inverse relation to Wc/Wa. Additionally, the characterization of the spent coffee grounds was performed with respect to the centesimal composition, density and granulometric distribution. It was observed increasing the density and particle size with moisture increasing. It was shown that the cyclone could be an efficient dryer for particulate solids with the advantages of high moisture reduction within short residence time.


Heat-mass transfer; biomass; physical characterization of spent coffee grounds: gas-solid flow

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DOI: http://dx.doi.org/10.25186/cs.v9i1.544


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