ANALYSIS OF THE FLOW OF A FIBROUS SUSPENSION IN A GRINDING PLANT IN THE PRODUCTION OF FINE CELLULOSE

Abstract

Of the various methods for obtaining microcrystalline cellulose (mechanical, chemical, thermomechanical, planting cellulose in powder form from its solutions), the most common is acid hydrolysis of cellulose. The difficulty of obtaining MCC from vegetable raw materials is that, in addition to cellulose, it contains in its composition such compounds as lignin, hemicelluloses, various extractive substances and an insignificant percentage of minerals. When grinding plant fibers in an aqueous medium, both a purely mechanical process of changing the size and shape of fibers and a colloidal chemical process called fiber hydration occurs. Mechanical phenomena are expressed in the shortening of fibers, their longitudinal splitting into fibrils, an increase in the outer surface and the number of free hydroxyl groups on their surface. The term hydration refers to colloidal chemical phenomena that begin with the swelling of hydrophilic plant fibers.
 The paper considers methods for obtaining microcrystalline cellulose and factors influencing the development of a fibrous suspension isolated from coniferous wood species in a grinding plant with inertial bodies. Multiphysical models of the flow of fibrous suspension in the installation are constructed. A study of the effect of grinding a fibrous suspension on the process of obtaining fine cellulose was carried out. The indicators of the finished product are given. The change in the degree of polymerization of cellulose that has previously passed the grinding stage, with different degrees of grinding according to the Shopper-Rigler, is analyzed. Data on cost reduction and resource savings (acid concentration, temperature and processing time) in the process of obtaining fine cellulose are presented.