Experimental determination of parameters for milk whey microfiltration process

Abstract

New types of polymer membranes being produced on an industrial scale, there appeared a viable possibility to solve the problem of lactose-containing raw material processing by developing complex membrane technologies and introducing them into dairy processing industry. The main objective of the research was theoretical justification and experimental determination of curd and cheese whey microfiltration mode base values. For this purpose we used membranes with the average conventional pore size (ACSP) 0.1 μm and 0.2 μm. Fresh and reconstituted curd whey’s were used as raw materials. Both types of whey comply with the industry standard requirements GOST R 53438-2009 by the key parameters. The KrosFlo® Research IIi TFF Tangential Flow Filtration System was used for the experimental study of the most important mechanisms of curd and cheese whey microfiltration process. Due to its peculiar design, it is possible to use cassettes with the polymer membrane elements with the total active filtration area of 0.01 m2 for the microfiltration of liquid polydisperse systems as well as to control the circulation speed at constant pressure and carry out the process at varied pressure and constant speed. During whey microfiltration the main factors that influence polymer membrane selectivity and permeability are duration (τ), process temperature (t), operating pressure value (P), separated system circulation rate (V), its dry solid weight ratio (C). The following values should be taken for the optimum values of the key factors having the most significant influence on the parameters (Q and φ) of the microfiltration process of the curd whey produced at Dairy Plant “Stavropolsky”: the duration of the microfiltration process before membrane washing and recovery τ = 100-120 min.; the operating pressure in the cassette apparatus membrane channel Р = 0.15-0.2 MPa; the separated system circulation rate in the cassette apparatus circuit V = 0.1-0.15 m/s; the separated system temperature t = 13-15°С; the acceptable dry solids weight ratio in the separated system is no more than С = 6-6.1%. For cheese whey: the duration of the microfiltration process before membrane washing and recovery τ = 90-110 min.; the operating pressure in the cassette apparatus membrane channel Р = 0.18-0.22 MPa; the separated system circulation rate in the cassette apparatus circuit V = 0.15-0.2 m/s; the separated system temperature t = 12-14°С; the acceptable dry solids weight ratio in the separated system is no more than С = 6-6.1%. The experiments proved that 0.1 μm and 0.2 μm ACSP membranes can be used for curd and cheese whey microfiltration as their permeability and selectivity characteristics are the same, other factors being equal and τ, t and C values being constant