Pashchenko B. Regularities of the of membrane separation of dispersed systems with concideration for structural and mechanical parameters of filter elements and sediment

The dissertation is devoted to the solution of urgent problems of investigation the regularities of the process of membrane separation of disperse systems, taking into account the structural and mechanical parameters of ceramic filter elements and the compaction of the sediment layer that occurs on their surface. Based on the analysis of the scientific literature and our own experimental studies it was found, that none of the theoretical models takes into account the deformation of ceramic filter elements during the ultrafiltration process which, together with the formation of a sedimentary layer, affects the characteristics of the membrane itself and the process parameters. The experimentally obtained numerical values and graphical dependences of the decrease in ultrafiltration productivity and the flow rate of the washing solution during the washing of the ceramic element on the duration of the process. A method has been developed for theoretical research of the process of membrane separation of liquid dispersion systems. A mathematical model of ultrafiltration with using ceramic filter elements has been developed, taking into account into account the structural and mechanical parameters of the membrane element and the sediment layer, patterns of change of their permeability coefficient. The design scheme of the ultrafiltration process based on the representation of the filter element in the form of porous moisture-proof framework containing a liquid dispersion system is developed. Such a continuum approach makes it possible to take into account the time variation of the sediment permeability coefficient under the action of operational load. The mechanism of overlapping the passage section of the pore due to the elastic-plastic deformation of the sediment layer is investigated. For this, on the basis of Slichter's theory, model of deformable porous continuous-discrete dispersed material is developed, that effectively reflects the nature of the porous structure change of the filtering medium. The developed algorithms are used as the basis of the created digital model PLAST-GiD. The main result of the simulation is the determination of dependencies of the decrease in the productivity of ultrafiltration equipment on changes in the permeability coefficient and compaction of the sediment layer, as well as numerical values of the permeability coefficient and changes in the diameter of its particles. The porosity of the membrane element varies from 0,51 to 0,46, and the permeability coefficient varies from 1.1 to 0.9 m3/(m2∙s∙Pa). The theoretical time to complete blocking of pores was 1595 s, and during physical experiment it was about 1600 s. The adequacy of the developed mathematical description by Fisher's criterion is proved. The results of the carried out scientific researchers are put into production: at the processing enterprise of Company Limited “Solomensky MZP” and also introduced into the educational process of the National University of Food Technologies.