Filtration is often a crucial step in modern industrial processes, where the separation of substances based on particle size or chemical properties is carried out, or simply for protecting process components and the final product. The master's thesis focuses on the filtration process of molten polyamide 6 and masterbatch based on polyamide 6 matrix during the production of filament yarn. The research utilizes physical models of blocking filtration laws to predict the increase in pressure of the polyamide 6 melt during filter clogging. The work encompasses theoretical foundations of rheology, fluid mechanics, and blocking filtration via constant pressure drop and constant volumetric flow.
The filter clogging process is analysed through four mechanisms: complete clogging, partial clogging, standard clogging, and clogging of the filter cake. Based on rheological measurements from a capillary rheometer to determine the flow behaviour index of the melt and the dispersibility of pigment filler in the masterbatch through a filter pressure value test following the SIST EN ISO 23900-5:2018 standard, blocking constants are calculated for various mechanisms during the filter pressure value test. These constants are then applied together with measurements of the initial filtration pressure in the nozzle package for both white and black masterbatches to predict the pressure increase on the production line.
A good match is observed in the predictions of the complete blocking model for the white masterbatch and satisfactory success of the standard clogging model for the black base mixture. Nevertheless, the models are constrained by the choice of filter during the analysis process and the filter during actual usage on the production line. Another crucial factor influencing the accuracy of model equations is the material's homogeneity.
|
