Use of a rotational bench viscometer to study the influence of temperatureand agitation speed on vinasse viscosity

Brookfield R.V.T. apparent viscosity measurements of 31.1 to 73 degrees Bri x vinasses, with and without nondissolved solids (N.D.S.), were carried out at varying rotation speeds (N) and temperatures (T). A regression analysis of this data was carried out to select the corresponding mathematical mode ls. It was concluded that apparent Brookfield viscosity for low concentrati on vinasses (up to 52.4 degrees Brix) depends only on linear and quadratic temperature terms. At higher concentrations (66 degrees and 73 degrees Brix ) regression models for apparent viscosity, must also include quadratic as well as rotation speed-temperature interaction terms. This behavior is disc ussed, identifying two types of rheological behaviors and advancing a preli minary hypothesis about the role of solutes, N.D.S. and temperature.