1. Introduction to ultrafiltration equipment:

Ultrafiltration (UF) is a membrane separation technology that can purify and separate solutions. The ultrafiltration membrane system is a solution separation device that uses ultrafiltration membrane fibers as the filtration medium and the pressure difference on both sides of the membrane as the driving force. Ultrafiltration membranes only allow solvents (such as water molecules), inorganic salts, and small organic molecules in the solution to pass through, while intercepting large molecular substances such as suspended solids, colloids, proteins, and microorganisms in the solution, thereby achieving the purpose of purification or separation.

Ultrafiltration membranes are widely used in water treatment projects. Ultrafiltration technology is playing an increasingly important role in fields such as reverse osmosis pretreatment, drinking water treatment, and reclaimed water reuse. Ultrafiltration technology plays a key role in the sterilization and turbidity removal of alcoholic beverages, the removal of heat sources from drugs, and the concentration process of food and pharmaceuticals.

The definition of the range of ultrafiltration pore size and molecular weight cut-off (MWCO) has always been vague. It is generally believed that the filtration pore size of ultrafiltration membranes is 0.001-0.1 microns, and the molecular weight cut-off (MWCO) is 1000-1000000 Dalton. Strictly speaking, the filtration pore size of ultrafiltration membrane is 0.001-0.01 microns, and the molecular weight cut-off is 1000-300000 Dalton. If the filtration pore size is greater than 0.01 microns or the molecular weight cut-off is greater than 300000 Dalton, the microporous membrane should be defined as a microfiltration membrane or a fine filtration membrane.

The nominal cut-off molecular weight of ultrafiltration membranes commonly used for water treatment is 30000-30000 Dalton, while ultrafiltration membranes with a cut-off molecular weight of 6000-30000 Dalton are mostly used in the fields of material separation, concentration, sterilization, and heat source removal.

The form of ultrafiltration membrane can be divided into two types: plate type and tube type. Tubular ultrafiltration membranes are divided into hollow fiber, capillary, and tubular types according to their different diameters. The ultrafiltration membranes used for water treatment in the market are mainly capillary type, and the hollow fiber (inner diameter 0.1-0.5mm) polyethylene or polypropylene microporous membranes used in some projects should actually belong to microfiltration membranes.

The assembly of ultrafiltration membrane fibers into components that can be connected to ultrafiltration systems is called ultrafiltration membrane components. Ultrafiltration membrane components are divided into three types: internal pressure, external pressure, and immersion. The driving force for submerged ultrafiltration membrane filtration is the pressure difference between the vacuum inside the membrane tube and atmospheric pressure. For ultrafiltration membranes with high filtration accuracy requirements, this pressure difference is usually not easy to meet the required filtration driving force. Therefore, the submerged component form is more suitable for ultrafiltration membranes or microfiltration membranes with lower filtration accuracy. External pressure ultrafiltration has extremely uneven flow velocity of liquid on the membrane surface during forward and reverse flushing, which affects the flushing effect of the membrane surface. Therefore, the ultrafiltration membrane commonly used in water treatment still has the advantage of internal pressure component structure.

2. Working principle of ultrafiltration equipment

Ultrafiltration is a membrane separation process that uses sieving as the separation principle and pressure as the driving force. The filtration accuracy is in the range of 0.005-0.01 μ m, and it can effectively remove particles, colloids, bacteria, heat sources, and high molecular weight organic substances from water. It can be widely used for the separation, concentration, and purification of substances. The ultrafiltration process has no phase transformation and operates at room temperature, making it particularly suitable for the separation of thermosensitive substances. It has good temperature resistance, acid and alkali resistance, and oxidation resistance, and can be used continuously for a long time below 60 ℃ and pH 2-11.

3. Classification of ultrafiltration membranes

Ultrafiltration membranes can be divided into various structures according to their structural types, such as plate frame (plate type), hollow fiber type, nano membrane surface ultrafiltration membrane, tube type, roll type, etc. Among them, hollow fiber ultrafiltration membrane is the most mature and advanced form of ultrafiltration technology. Hollow fiber has an outer diameter of 0.4-2.0mm and an inner diameter of 0.3-1.4mm. The wall of the hollow fiber tube is covered with micropores, and the pore size is expressed as the molecular weight that can intercept substances. The intercepted molecular weight can reach several thousand to several hundred thousand. The raw water flows under pressure outside or inside the hollow fibers, forming external and internal pressure hollow ultrafiltration membranes, respectively. Ultrafiltration is a dynamic filtration process, in which intercepted substances can be removed with concentrated solution without blocking the membrane surface, and can operate continuously for a long time.

4. The application of its technology

Early industrial ultrafiltration was applied to wastewater and sewage treatment. Over the past thirty years, with the development of ultrafiltration technology, the application fields of ultrafiltration membrane technology have become very wide, mainly including food industry, beverage industry, dairy industry, biological fermentation, biomedicine, pharmaceutical and chemical industry, biological preparations, traditional Chinese medicine preparations, clinical medicine, printing and dyeing wastewater, food industry wastewater treatment, resource recovery, and environmental engineering, etc.

5. Advantages

A. The ultrafiltration membrane components use products from world-renowned membrane companies, ensuring that customers receive high-quality organic membrane components from around the world, thereby ensuring retention performance and membrane flux.

B. The system has a high recovery rate and produces high-quality products, which can achieve efficient separation, purification, and high fold concentration of materials.

C. The processing process has no phase change and has no adverse effects on the composition of the material. The separation, purification, and concentration processes are always at room temperature, making it particularly suitable for the treatment of thermosensitive substances. It completely avoids the disadvantage of high temperature damaging bioactive substances and effectively preserves the bioactive substances and nutrients in the raw material system.

D. The system has low energy consumption, short production cycle, and lower operating costs compared to traditional process equipment. It can effectively reduce production costs and improve the economic efficiency of enterprises.

E. The system has advanced process design, high integration degree, compact structure, small footprint, easy operation and maintenance, and low labor intensity for workers.

F. The system is made of sanitary grade control valves, and the site is clean and hygienic, meeting the requirements of GMP or FDA production standards.

G. The control system can be personalized according to users' specific usage requirements, combined with advanced control software, to centrally monitor important process operating parameters online on site, avoiding manual errors and ensuring long-term stable operation of the system from multiple perspectives.

6. Ultrafiltration application

Recycling and utilization of sewage and wastewater

Surface water treatment: Most ultrafiltration equipment is used for surface water treatment, and the treated water is used for irrigation or as inlet for reverse osmosis to prepare industrial water. The number of such factories is gradually increasing in places such as the Netherlands. This technique provides access to surface water nearby without the need to purchase increasingly expensive drinking water.

Drinking water treatment: With the improvement of living standards, people's requirements for the quality of drinking water are becoming increasingly high. Water treatment companies pay attention to controlling the amount of microorganisms present in the water supply network. To achieve this, one way is to stop expensive and frequent water quality inspections, perhaps by setting up barriers at water supply terminals to prevent bacteria and viruses from entering. By adopting the UF system, it is very convenient to build such fences. The removal rate of bacteria by ultrafiltration membrane can reach 6log, and the removal rate of viruses can reach 4log, which is why water plants and users do not have to worry about bacteria and viruses. Because the quality of drinking water itself is very high, the membrane system at this time can adopt a high membrane flux, which can reach 135 liters per square meter Hour. At the same time, the premise of high water inflow is that the frequency of backwashing and chemical enhanced backwashing can be very low, and the water production can reach 99%. If necessary, a secondary ultrafiltration device can be set up to further reuse the backwash water from the first stage.

Used for seawater desalination: The Middle East is a place where water capital is severely lacking. To understand this title, people often use distillation techniques. Since the 1860s, membrane techniques have been used to address water scarcity in these countries. However, many reverse osmosis seawater desalination systems (using semi permeable membranes to desalinate seawater and produce seawater) face the problem of severe membrane fouling. The important reason is that traditional pretreatment methods for reverse osmosis systems cannot provide reliable inlet water quality. It is to dilute the water output of factories as much as possible, even when the water output is far below their designed capacity, and some factories' water output may not reach 30% of the final design. The research on small-scale desalination devices is very clear, and ultrafiltration systems can effectively control the quality of seawater, providing high-quality influent for reverse osmosis systems. The durability experiment also revealed that the SDI value of the ultrafiltration system's effluent can be well controlled below 2. These tests do not require any pre-treatment before the ultrafiltration system (also known as ultrafiltration equipment) and are applicable to various types of seawater quality.