The Spiral Baffle Membrane Separator Flow Characteristic And Its Separation Performance Research

To suppress concentration polarization and membrane fouling phenomenon of the membrane separation process, strengthening membrane separation process, and expanding the application field of membrane separation, this project proposed a new form of membrane separation, spiral baffle membrane separator. First, with FLUENT software, this article simulated fluid flow within the spiral baffle membrane separator, to analyze the flow field characteristics and its separation mechanism. Then, the flow channel structure parameters were optimized, and as a basis to build an experimental device, studying the separation of the performance characteristics of the new membrane separator. Finally, based on the built-in membrane tube type spiral membrane separator, we developed spiral flow filter, and realized its industrial operation. Through research, we draw the following conclusions:(1) Firstly, the corner vortex caused by the wall of the spiral baffle membrane separator, can better inhabit the deposition of fine particles on the portion of the membrane surface. Built-in tubular membrane spiral baffle membrane separator, rely mainly on the density difference between the solid-liquid two phase of suspensions subjected to different centrifugal force, to suppress the deposition of particles on the membrane surface, suitable for separating particles of density greater than the liquid phase, and larger density difference suspension. The external tubular membrane spiral separator is different, because of the Dean secondary flow near the membrane surface, the particles deposited on membrane surface can be taken back to the mainstream, thereby reducing the concentration polarization and membrane fouling phenomenon. So, the external tubular membrane spiral separator is appropriate for separating small or similar density difference suspensions.(2) Secondly, through the study of rectangular cross-section spiral flow, the flow is unstable when De is about 246, generating Dean secondary. Rectangular cross-section spiral flow with section ratio between 2.5 to 3.5, helix angle between 10.4° to 21.2 °is better for spiral baffle membrane separator.(3) Thirdly, the operating pressure can improve membrane flux better than the feed rate,increasing feed concentration will lead to a decline membrane permeate flux. Operating pressures in experiment are below the critical pressure, critical pressure for the spiral baffle membrane separator remains to be studied experimentally.(4) Based on the same principle of the built-in membrane separator, the spiral flow filter better solved the separation of cross-density suspension in industry.