membrane processes
There are two main flow configurations of membrane processes: cross-flow (or) tangential flow and dead-end filtrations. In cross-flow filtration the feed flow is tangential to the surface of membrane, retentate is removed from the same side further downstream, whereas the permeate flow is tracked on the other side. In dead-end filtration the direction of the fluid flow is normal to the membrane surface. Both flow geometries offer some advantages and disadvantages. Generally, dead-end filtration is used for feasibility studies on a laboratory scale.
The dead-end membranes are relatively easy to fabricate which reduces the cost of the separation process. The dead-end membrane separation process is easy to implement and the process is usually cheaper than cross-flow membranes filtration. The dead-end filtration process is usually a batch-type process, where the filtering solution is loaded (or slowly fed) into the membranes device, which then allows passage of some particles subject to the driving force. The main disadvantage of a dead end filtration is the extensive membranes fouling and concentration polarization. The fouling is usually induced faster at higher driving forces.
ล้างmembrane (ล้างเมมเบรน)
ล้างmembrane (ล้างเมมเบรน) fouling and particle retention in a feed solution also builds up a concentration gradients and particle back flow (concentration polarization). The tangential flow devices are more cost and labor-intensive, but they are less susceptible to fouling due to the sweeping effects and high shear rates of the passing flow. The most commonly used synthetic membrane devices (modules) are flat sheets/plates, spiral wounds, and hollow fibers.
Flat plates are usually constructed as circular thin flat membrane …
