GRINDING AND FRACTIONATION OF DRIED PLANT MATERIALS
Authors:   Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine, Ukraine, Sniezhkin Yurii , Shapar Raisa ,   Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine, Ukraine, Husarova Olena ,   National Academy of Sciences of Ukraine, Ukraine
Published: May 2021

In the absence of large-scale pectin production in Ukraine, pectin-containing powders are an alternative source. They are used as natural additives in the manufacture of health products, due primarily to the presence of pectin, as well as other useful natural components of raw materials. The purpose of the work is to conduct research on the dispersion and fractionation of dried plant materials and to determine the energy-saving regimes of these processes. The task of the research is to develop optimal modes of dispersion of dried plant materials; determine the depend-ence of the micromill performance and power consumption on the rotation speed of the dispersant rotor; to establish the influence of the load on the sieve and the scattering time on the fractionation process. Objects, equipment and research methods. Dried pectin-containing apples and table beets were used as research objects. Studies of the dispersion process were performed on an micromill (8-MM), the coarse part was ground on a disintegrator (ДЕЗІ), the study of the dispersed composition of powders was carried out on the device 029. The paper analyzes the existing methods of grinding and equipment for its implementation. The analysis showed that percussion mills are the most suitable for grinding dried pectin-containing apples and table beets. The dispersed composition of pectin-containing powders is determined in the article. The influence of material loading on the sieve and scattering time on the yield of the fine fraction was investigated. It is proved that the scattering process is more influenced by the scattering time. The paper graphically shows the effect of rotor speed on the equivalent particle diameter and powder dispersion; differential and integral particle distribution curves depending on rotor speed and scattering time for apple and beet powders; the dependence of micromill productivity and power consumption on the speed of the disperser rotor, etc. The optimal operating speed of the rotor is 50 m/s. At this speed, energy consumption for grinding dried materials is minimal. It is proved that the fractionation process almost does not depend on the load on the sieve, but depends on the scattering time. It is impractical to increase the process duration over 3 minutes. Increasing the time to 4 minutes increases the mass of the fine fraction by only 2…5%. The yield of the fine fraction of powders according to the optimal modes of dispersion and separation is: apple – 65...68%, beet – 62...65%. The possibility of re-grinding in order to increase the fine fraction yield is shown. Conclusions. According to the results of the research, the optimal dispersion regimes, the dependence of micromill productivity and power consumption on the dispersant rotor speed, as well as the effect of load on the sieve and scattering time of apple and beet powders on the fractionation process are determined. On the basis of the conducted researches energy-saving conditions of processes of dispersion and fractionation of pectin-containing powders and proper work of the corresponding equipment are defined.