A unit composed of a membrane, a support for fixing the membrane, a spacer, and a container accommodating these members is referred to as a membrane module. The membrane module has a plate-and-frame type, a tube type, a spiral type, and a hollow fiber type. Industry Scale Weighing Indicator,Mettler Toledo Type Ex Indicator,Mettler Toledo Type Scale Indicator,Ex Proof Weight Indicator Changzhou Weibo Weighing Equipment CO .,LTD , https://www.webowtscale.com
A unit composed of a membrane, a support for fixing the membrane, a spacer, and a container accommodating these members is referred to as a membrane module. The membrane module has a plate-and-frame type, a tube type, a spiral type, and a hollow fiber type.
The membrane module should have the following requirements:
1. The fluid on the raw material side and the permeate side has a good flow state to reduce back mixing, concentration polarization and membrane fouling.
2. Have the highest possible packing density.
3. It can provide high mechanical support to the membrane, good sealing performance, and convenient installation and replacement of the membrane.
4, suitable for specific operating conditions, safe and reliable, easy to repair.
5. Low equipment cost and low operating cost.
1. Plate and frame membrane module:
The plate-and-frame membrane module structure is similar to the plate-and-frame filter device. The membrane is placed on the porous support plate of the filter paper, and the two porous support plates are stacked together to form a liquid flow channel space to form a membrane unit. The unit and the unit can be connected in parallel or in series.
The plate and frame membrane module has a large specific surface area and is easy to change the membrane, which is suitable for ultrafiltration and microfiltration.
Second, tubular membrane components:
The tubular membrane module has an internal pressure type and an external pressure type. The internal pressure membrane module is a membrane that is cast in a porous stainless steel "target=_blank> stainless steel tube or a plastic tube reinforced with glass fiber. The pressurized liquid flows through the tube, and the permeate solution permeating through the membrane is collected outside the tube. The external pressure membrane module is a membrane cast on the outer side of the porous support tube, the pressurized liquid flows through the outside of the tube, and the permeation solution permeates through the membrane into the porous support tube from the outside of the tube. Both the internal pressure type and the external pressure type can be Designed to connect in series or in parallel as needed.
The tubular membrane module has the advantages of simple structure, strong adaptability, small pressure loss, large permeation, convenient cleaning and installation, high pressure resistance, suitable for handling high viscosity and thick liquid, suitable for ultrafiltration and microfiltration. However, the specific surface area is small.
Third, spiral wound membrane module:
The spiral wound membrane module structure is similar to a spiral plate heat exchanger. In the middle of the membrane bag is a porous support plate, the two sides are membranes, the three sides of the membrane bag are sealed, and the fourth side is connected with the porous central tube. During assembly, a layer of mesh material (separate mesh) is laid on the film bag, and rolled around the center tube into a cylindrical shape in a cylindrical pressure vessel. After the pressurized liquid enters the assembly, the flow path in the mesh flows in a direction parallel to the central tube, and the permeate enters the film bag and flows in a spiral direction, and finally collects and discharges in the central tube.
The spiral wound membrane module is compact and has a high packing density. The disadvantage is that the manufacturing process is complicated and the film cleaning is difficult.
Fourth, hollow fiber membrane module:
The membrane material is made into a hollow tube having an outer diameter of 80 to 400 μm and an inner diameter of 40 to 100 μm, which is a hollow fiber membrane. A large number of hollow fiber membranes were sealed at one end, and the other end was cast into a tube sheet with an epoxy resin, and placed in a cylindrical pressure vessel to constitute a hollow fiber membrane module. The hollow fiber membrane module has an internal pressure type and an external pressure type, and most of them adopt an external pressure type, that is, a high pressure liquid liquid is measured and flowed outside the hollow fiber membrane, and the permeate enters the inside of the hollow fiber membrane.
Hollow fiber membrane modules are extremely densely packed and do not require additional support materials. However, the membrane is easily clogged and cleaning is not easy.
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