Effect of transmembrane pressure on microfiltration concentration of yeast biomass

Аннотация

An experimental study on the separation of mature molasses broth using a microfiltration unit with a plate-and-frame module has been carried out, and data on the flux and the rejection factor for MMPA⁺ (P = 0.05 or 0.1 MPa), MPS (P = 0.3 or 0.5 MPa), and MFFK (P = 0.05, 0.1, 0.3, or 0.5 MPa) membranes have been obtained. The revealed relations of the flux to the separation time and the transmembrane pressure for the membranes under study indicate that a dynamic membrane forms during the separation of the molasses broth. This dynamic membrane serves as an additional barrier to the solvent and is eventually compacted to retard yeast cells and polysaccharides and pass more than 80% of ethyl alcohol. The flux for the MFFK and MPS membranes in the separation of mature molasses broth increases with increasing transmembrane pressure, a change that is associated with an increase in the working pressure as the driving force of the process, in contrast to the MMPA⁺ membrane, whose performance is affected by rapid pore clogging and adsorption phenomena, as well as by the appearance of pressure-induced deformations in the form of profiled lines along and across the membrane. Visual analysis of the spent sample of the MFFK membrane, obtained at P = 0.05 MPa and subjected to flushing the dynamic membrane with distilled water for 1200 s, has revealed that the membrane after disassembling the device shows accumulations of various membrane-forming substances (yeast and polysaccharides) in isolated areas at the exit of the flat channel of the device. It is noted that the closer the outlet of the flat channel of the membrane unit, the darker the areas because of the greater accumulation of the membrane-forming yeast and polysaccharide particles.