The Study On Performance Of Microfiltration Of Vibratory Shear Enhanced Processing

Concentration polarization and membrane fouling are two important influential factors of performance of filtration. Traditional cross-flow filtration only relys on increasing fluid rate to improve shear rate on the membrane face, but the energy consumption is high. As a new type dynamic filtration system, in the condition of low rate of feed. Vibrotary Shear Enhanced Processing could reduce concentration polarization and membrane fouling and get good performance of filtration through equipment itself periodical torsion vibration produce high shear rate on the membrane face.This paper respectively connects the tubular membrane or flat membrane with the vibratory section of VSEP, and studys the microfiltrations of calcium carbonat suspension and yeast suspension. Through these experiments, the lower concentration of the feed, the higher vibratory frequency and amplitude all can slow down the declinational trendency of filtration flux and get higher steady filtration flux. For the calcium carbonat suspension, the fouling resistance and transmembrane pressure corresponding to the steady filtration flux both increase with the rising of feed concentration and decrease with the drop of vibratory frequency and amplitude. For the yeast suspension, at different concention, the relationships of steady filtration flux and shear rate all conform to the formula of Js=kγmn. During the processing of experiment, the turbidity of the two suspensions both decrease with time, but the decrease rate of calcium carbonat is obviously higher than the yeast suspension's. Meanwhile, the fouling of tubular membrane and flat membrane are compared. The cake on the surface of tubular membrane is thin and uniform, and the thickness of cake on the surface of flat membrane is thinner when the radius is larger.This paper uses the software of MATLAB to calculate the distributions of the rate and the shear rate in the annular gap of tubular membrane device when vibrating and no vibrating. Through the results of the calculation, the rate and shear rate of vibrating are both higher than no vibrating. Using the methods of dimensional analysis and orthogonal, the empirical models of steady filtration flux of calcium carbonat suspension and yeast suspension are respectively got. The influential factors of steady filtration flux are summed up into some important dimemsionless numbers like Re and Eu to obtain the feasible formulas that provide basis for scale-up and optimization of the module.