Application Progress and Precautions of Hollow Fiber Membrane

A hollow fiber membrane is an important form of the separation membrane. Among the unit volume membrane modules, the hollow fiber membrane has the largest effective membrane area, and the filtration and separation efficiency is high. The membrane is easy to clean, simple in structure, convenient to operate and does not produce secondary pollution in the production process, so it is widely used. Hollow fiber membranes are one of the most important forms of membrane filtration. The hollow fiber membranes produced by hollow fiber membrane manufacturers are capillary-shaped, with micropores located on the wall of the tube. Solution separation means that its components can pass through these micropores.

Ⅰ. Application of hollow fiber membranes in tap water purification

The new drinking water quality standard (CJ94-2005) has been fully integrated with the international drinking water standards. The new standard has greatly improved water quality requirements. In the face of the new water quality standards, the limitations of existing conventional water treatment processes (coagulation/sedimentation/filtration/disinfection) will become more and more obvious. Ultrafiltration is a more efficient water treatment technology and has great competitiveness in the field of drinking water treatment.

Advantages of hollow fiber membrane:

①It has a high removal rate, with a removal rate of bacteria exceeding 6log, and virus exceeding 4log, so there is no need to worry about bacteria and virus contamination.

②It has a high production water flux, up to 85~110L/m2·h.

③It has a high water yield rate, up to 95~99%.

Ⅱ. Application of hollow fiber membranes in surface water and groundwater treatment

Ultrafiltration membrane separation technology has been widely used in surface water and groundwater treatment and the treated water can be used as reverse osmosis feed water to prepare process water. This technology provides a new type of industrial water production method.

Advantages of hollow fiber membrane:

① Hollow fiber membrane has a high production water flux, up to 70~100L/m2·h.

② Strong ability to resist water quality fluctuation.

③ It has a high water production rate, up to 90%.

④ Low water costs, saving corporate costs.

Ⅲ. Application of hollow fiber membrane in seawater desalination pretreatment

The Middle East is a place with serious water shortages. In order to solve this problem, people used distillation technology to desalinate seawater. Since the 1860s, membrane technology has been used to solve the water shortage problem in these countries. However, many reverse osmosis desalination systems face serious membrane pollution problems, mainly because the traditional pretreatment methods of reverse osmosis systems cannot provide reliable incoming water quality. As a pretreatment section of reverse osmosis, ultrafiltration can ensure the stable inflow and quality of reverse osmosis.

Advantages of hollow fiber ultrafiltration membrane:

① The ultrafiltration membrane has high flux, up to 80~100L/m2·h.

② High water production rate, up to 80~90%.

③ The product water quality is excellent. It fully meets the reverse osmosis water inlet conditions with SDI≤2.

④ Small footprint.

⑤ Extend the service life of reverse osmosis membrane.

Notes:

A. The filtration system should be sterilized regularly.

Ultrafiltration membranes can retain bacteria, but cannot kill bacteria. No matter how good the retention rate is, the ultrafiltration membrane cannot guarantee for a long time that no one bacteria will grow in the clean area. If there are bacteria, it may multiply and directly affect the quality of the permeated water. For example, semi-transparent filamentous, white flocculent mold clusters appear in some mineral water, which is mainly caused by mold contamination of the system. Therefore, it is necessary to regularly sterilize the turnover environment and filtration system. The sterilization operation cycle depends on the quality of the raw water supply. For ordinary urban tap water, it is 7 to 10 days in summer, 30 to 40 days in winter, and 20-30 days for spring and autumn. When surface water is used as the water supply source, the sterilization cycle is shorter. Sterilized drugs can be circulated or soaked in 500-1000mg/L sodium hypochlorite solution or 1% hydrogen peroxide aqueous solution for about half an hour.

B. Since each ultrafiltration module is added with protective liquid before leaving the factory, the protective liquid in the module should be thoroughly rinsed before use. First, rinse water with low pressure (0.1MPa) for 1 hour, and then with high pressure (0.2MPa) for 1 hour. Regardless of low-pressure or high-pressure flushing, the production water discharge valve of the system should all be opened. When using product water, check and confirm that the product water does not contain any fungicides.

C. Handle the ultrafiltration components with care and pay attention to protection. As the ultrafiltration components are precision equipment, you must be careful during installation. Also, to remember that handle them with care, and never shake them. If the components are not used, they should be rinsed with clean water first, and then disinfected and sterilized by adding 0.5% formaldehyde aqueous solution, and sealed. For example, the components need to be antifreeze treatment in winter, otherwise, the components may be scrapped.