Influence of physicochemical parameters of the alkaline pretreatment on the viscosity of wheat straw slurries

The paper presents the results of the influence of physicochemical parameters of the alkaline pretreatment on the viscosity of wheat straw slurries on its rheological properties. The authors consider the coefficient of apparent viscosity as a complex indicator of wheat straw slurries pretreatment process which depends on the structure and physicochemical properties of system components, thermal parameters of the process (temperature, dispersion, and concentration of dispersed phase, shear flow rate). A wheat straw slurries with a solids content of 10?15% were chosen as the object of research. As a result of research, rheological viscosity and fluidity were constructed for these slurries in the range of shear rates from 1 to 437.4 s-1. The value of viscosity as a function of shear rate for a solids concentration of 10, 12, and 15% w. is given. It has been determined that in a certain range of shear rates the slurries show the behavior of viscoelastic fluids with yield stress, and with increasing of the solids concentration the rate of decrease of viscosity increases with increasing shear rate. A study of the effect of alkali concentration on apparent viscosity was performed. It is determined that an increase in the concentration of alkali leads to an increase in the apparent viscosity of the slurry, and with increasing alkali concentration, the rate of decrease in viscosity decreases with increasing shear rate. The value of the apparent viscosity of the suspension as a function of temperature is given.