Reseach On Filtration Characteristics And Engineering Application In Enhanced Crossflow Microfiltration Within Tubular Membrane Elements With Rotating Flow

Microfilltration within stationmary tubular membrane elements with rotating flow is one of the most efficient method to enhance crossflow microfiltration , but its flow field characteristics are far from understanding and its filtration characteristics are also had to reseach ,because the rotating flow field are superposed by rotating shear flow and axial flow and radial permeate flow. In this dissartation, by using the Particle Image Velocemetry(PIV) system and microfiltration of incompressible inorganic salt powder systemic investigation are made on the flow field of polyacrylate tubular membrane elements with rotating flow. It is compared the slurry inlet method between tangential and axial.Fisrt, The flow field of radial and tangential annulus with rotating flow are made by using an advanced PIV system , its flow field characteristics are obtained preliminary probed . It is found that the flow field characteristics are not the same between unpermeateing flow and have permeateing flow , otherwise the flow field is compared between rotating flow and dynamic tubular membrane.Sconed, the tangential shear velocity and the radial particle diameter distribution are derived according force balance in the annulus, in order to reduce or pervent the particle to remove toward the membrane surface.Third , the filtration experiment is made by using the inorganic saltand influencing factors on permeated flux are investigated , such as slurry inlet ways, concertration of suspension and pressure. The resultsare greater than those in the common crossflow microfiltration in the same condition. On the other hand , the operating pressure will change to be less trend with other enhanced crossflow microfiltration when the permeate flux arriving a steady value.Fourth, the membrane recovering method was found within stationary tubular membrane elements and was compared with rotating flow by using experiment, that is, the unloading pressure recovering method is one of the most efficient method, it may reduce the auxiliary time, such as washing , backflush, reverse filtration, but the tubular membrane is washed or backflush or changed after the cycle period are accumulated numerous times.Last the above method is applied in engineering, the permeating flux is bigger than original in the same condition and the energy consum is roduced about 40%.