Technical process analysis of ultrafiltration equipment

The ultrafiltration membrane module is a membrane separation process driven by pressure. Through the micropore screening on the membrane surface, particles and impurities with a diameter of 0.002-0.1μm can be intercepted, and colloids, silicon, proteins, microorganisms and impurities in water can be effectively removed. organic macromolecules. When the liquid mixture flows through the surface of the membrane under a certain pressure, the solvent and small molecular substances pass through the membrane, while the macromolecular substances are intercepted, so as to achieve the purpose of separation and purification between the size and molecules. It can be widely used in the separation, concentration and purification of substances. The ultrafiltration process has no phase inversion, does not require heating, operates at room temperature, saves energy, and is especially suitable for the separation of heat-sensitive substances. The ultrafiltration process is simple, there are few supporting devices, the operation is simple, and the maintenance cost is low. The ultrafiltration membrane is resistant to chemical erosion, and has a wide range of PH adaptability. The membrane area per unit volume of the ultrafiltration device is the largest, the investment cost is the lowest, and the cleaning is simple.

Application of ultrafiltration equipment

Early industrial ultrafiltration was used in wastewater and sewage treatment. With the development of ultrafiltration technology, the application fields of ultrafiltration membrane technology have been very wide, mainly including food industry, beverage industry, dairy industry, biological fermentation, biomedicine, pharmaceutical chemical industry, biological preparations, traditional Chinese medicine preparations, clinical medicine, printing and dyeing Wastewater, food industry wastewater treatment, resource recovery and environmental engineering, etc.

Process flow of ultrafiltration equipment

The ultrafiltration device is carried out in a closed container, and the compressed air is used as the power to push the piston in the container forward to make the sample liquid form an internal pressure, and a solid membrane plate is installed at the bottom of the container. The small molecules smaller than the pore diameter of the membrane plate are squeezed out of the membrane plate under the action of pressure, and the large molecules are trapped on the membrane plate. At the beginning of ultrafiltration, because the solute molecules are evenly distributed in the solution, the speed of ultrafiltration is relatively fast. However, with the continuous discharge of small molecules, large molecules are trapped and accumulated on the surface of the membrane, and the concentration is getting higher and higher, forming a concentration gradient from bottom to top, and the ultrafiltration rate will gradually slow down today. This phenomenon is called concentration polarization.

In order to overcome the concentration polarization phenomenon and increase the flow rate, several ultrafiltration devices have been designed:

1. Non-stirring ultrafiltration

This kind of device is relatively simple, just apply a certain pressure in a closed container, so that small molecules and solvent molecules are squeezed out of the membrane, without a stirring device, the concentration polarization is more serious, and it is only suitable for a small amount of ultrafiltration with a relatively dilute concentration.

2. Agitated ultrafiltration

Stirring ultrafiltration is to place the ultrafiltration device on the electromagnetic stirrer, and put a magnetic rod in the ultrafiltration container. When applying pressure to the container during ultrafiltration, start the magnetic stirrer, small molecular solutes and solvent molecules are discharged out of the membrane, and when large molecules accumulate on the surface of the filter membrane, they are dispersed into the solution by the electromagnetic stirrer. This method is not easy to produce concentration polarization phenomenon, which improves the speed of ultrafiltration.

3. Hollow fiber ultrafiltration

Due to the membrane plate ultrafiltration device, the cut-off area is limited. Hollow fiber ultrafiltration is equipped with many hollow fiber capillaries in a hollow column, and the two ends are connected. The inner diameter of the tube is generally about 0.2mm, and the effective area can reach 1 square meter. Each fiber capillary in centimeters is like a miniature dialysis bag, which greatly increases the permeable surface area and improves the speed of ultrafiltration.

Xi’an CHIWATEC Water Treatment Technology is a high-tech enterprise specialized in various water processing devices. Aside from these individual products, which cover a number of types and series, we can also help with related comprehensive engineering projects. Thanks to our hard work and dedication upon our founding, we are now one of the fastest-developing water treatment equipment manufacturers in Western China.

Further reading

6TPH ultrafiltration

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