Nonstationary evaporation liquid solutions mathematical model application to describe brewer's grains filtrate drying kinetics

The aim of the study is to test the adequacy of the mathematical model of unsteady evaporation of liquid solutions under forced convection to describe the kinetics of drying the filtrate of brewer's grains. Re-search objectives: experimental study of the kinetics of drying the filtrate of brewer's grains and checking the adequacy of the mathematical model of unsteady evaporation of liquid solutions from an inert surface during forced convection to describe the drying curve and the drying rate curve. Experimental data are given at a drying agent temperature of 60 ° C on the kinetics of drying the brewer's grains filtrate obtained by squeezing raw brewer's grains on a mechanical press from the Maykop beer brewery. The average dry matter content of the two samples of brewer's grains filtrate was 6.26 %. The change in moisture content, moisture content of the filtrate and drying rate was determined. To describe the kinetics of drying the filtrate of brewer's grains, the previously developed by the authors a mathematical model of unsteady evaporation of liquid solutions from an inert surface under forced convection, which is a set of nonlinear equations, is used. Good qualitative and quantitative agreement was obtained. The relative deviation of the calculated data from the experimental data does not exceed 4 %. The observed velocity jump in the drying rate at the junction between the period of heating of the material and the period of removal of free moisture indicates an error or, possibly, the complexity of describing the transition point between periods. The period of removal of free moisture is described by an almost straight line, which corresponds to the known theoretical and practical concepts. To describe the kinetics of drying when removing bound moisture, it is recommended to take into account the adsorption effect of the interaction of moisture with a solid.