Rheology of acid suspensions containing cassava bagasse: Effect of biomass loading, acid content and temperature

Abstract

Understanding the characterization and rheological behavior of acid suspensions of cassava bagasse provides essential information for the design of conversion processes. Samples with different cassava bagasse concentrations (0–10% w∙w−1), phosphoric acid (0–10% w∙w−1) at temperatures between 278.13 and 318.13 K were submitted to steady-state flow over a wide range of shear rates (1–265 s−1). The biomass particles had considerable residual starch (~50% db), low lignin content and adequate particle size (<200 μm) for the conversion process. Flow curves were well-fitted to the Herschel-Bulkley model, presenting a Newtonian domain at low solids and acid content and a non-Newtonian behavior with noticeable yield stress and shear-thinning characteristic (n < 1) at above 6% of cassava bagasse. Resistance to flow increased as the solids loading and acid content increased. Temperature dependence could be expressed as a function of an Arrhenius-type equation with good accuracy of fit.