Publications in year 2016

Vol. 30, Issue 4



Mathematical models for prediction of rheological parameters in vinasses derived from sugar cane

International Agrophysics
Year : 2016
DOI : 10.1515/intag-2015-0083
Volumen : 30
Issue : 2
Pages : 135 - 141
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Authors: L. Chacua1, G. Ayala2, H. Rojas1, A. Agudelo1

1Faculty of Engineering and Administration, National University of Colombia, Palmira campus, AA 237, Colombia
2Faculty of Animal Science and Food Engineering, University of São Paulo, Av. Duque de Caxias Norte 225, 13635-000, Pirassununga, SP, Brazil
Abstract :

The rheological behaviour of vinasses derived from sugar cane was studied as a function of time (0 and 600 s),soluble solids content (44 and 60 °Brix), temperature (10 and 50°C), and shear rate (0.33 and 1.0 s-1). The results indicated that vinasses were time-independent at 25°C, where shear stress values ranged between 0.01 and 0.08 Pa. Flow curves showed a shear-thinning rheological behaviour in vinasses with a flow behaviour index between 0.69 and 0.89, for temperature between 10 and 20°C. With increasing temperature, the flow behaviour index was modified, reaching values close to 1.0. The Arrhenius model described well the thermal activation of shear stress and the consistency coefficient as a function of temperature. Activation energy from the Arrhenius model ranged between 31 and 45 kJ mol-1. Finally, the consistency coefficient as a function of the soluble solids content and temperature was well fitted using an exponential model (R2 = 0.951), showing that the soluble solids content and temperature have an opposite effect on consistency coefficient values.

Keywords : ethanol industry, vinasses, pseudoplastic, rheological models
Language : English