Preparation of space water, purified water, distilled water, etc; Water for alcohol manufacturing and alcohol reduction; Preparation of water for pharmaceutical, electronic and other industries in the early stage; Concentration, separation, purification, and water preparation of chemical processes; Demineralized soft water for boiler makeup water; Desalination of seawater and brackish water; Water and wastewater treatment in industries such as papermaking, electroplating, printing and dyeing. Membrane separation technology represented by polymer separation membrane, as a new and efficient fluid separation Unit operation technology, has made remarkable rapid development in the past 30 years and has been widely used in various fields of the national economy.
2. Current application status of reverse osmosis membranes:
Among various membrane separation technologies, reverse osmosis technology has been the most successful, rapidly developing, and widely used in China in recent years. It is estimated that the use of reverse osmosis membranes has increased by an average of 20% annually since 1995; According to conservative statistics, the market supply of industrial reverse osmosis membrane components in 1999 was 6000 units of 8-inch membranes and 26000 units of 4-inch membranes. The market was stronger in 2000 and 2010, with a significant increase in membrane usage year by year. It is estimated that the application of reverse osmosis technology has created an annual output value of over 1 billion RMB in the water treatment industry. The largest field of industrial application of reverse osmosis membranes in China is still large-scale boiler feed water and various industrial pure water, followed by the market size of drinking water. The applications in industries such as electronics, semiconductors, pharmaceuticals, healthcare, food, beverages, alcoholic beverages, chemicals, and environmental protection have also formed a certain scale.
3. Latest progress in reverse osmosis membranes:
Due to the advantages of saving electricity consumption and reducing the pressure level of related mechanical components, the application proportion of ultra-low pressure membranes has been increasing since 1999. This is most prominent in small devices that mainly use 4-inch membranes, and the application of ultra-low pressure membranes in large devices is also on the rise. Currently, the maximum water production capacity of the device that uses ultra-low pressure membranes is 650 tons/hour. Low pollution membrane fouling is the biggest hazard in reverse osmosis applications. At present, several low pollution membranes with strong anti pollution performance, long service life, low cleaning frequency, and easy cleaning have been introduced. Reverse osmosis membranes with positive charges are widely used. The materials of low-pressure and ultra-low-pressure composite membranes are aromatic polyamines, and their membrane surfaces have negative charges. Currently, membrane manufacturers have developed low-pressure composite membranes with positive charges on their surfaces, which are mainly used in the preparation of high-purity water systems with high electrical resistance. The positive charge film ES10C produced by Nippon Nippon Electric Company has achieved high purity water with a resistivity of 10-15 megaohms in the third level reverse osmosis system of the semiconductor industry; The total final water production capacity of the three production plants of Hyundai Electronics in South Korea is 800 tons/hour, and the water production resistivity of the tertiary reverse osmosis system is 8-9 megaohms; The 170 ton/hour three-level reverse osmosis system of a semiconductor factory in Shanghai also meets the above indicators. In addition, in the two-stage reverse osmosis system with a scale of 5-20 tons/hour in several pharmaceutical factories in China, a reverse osmosis water and electricity resistance rate of 1.7-3 megaohms has also been achieved. High temperature resistant, food grade, and hygiene grade reverse osmosis membranes are commonly used for water treatment. The operating temperature of reverse osmosis membranes is 0-45 degrees Celsius. However, in special situations where high-temperature sterilization at 90 degrees Celsius is required, high-temperature and chemical resistant reverse osmosis membranes can be used. In addition, various food grade or hygiene grade reverse osmosis membranes with special membrane element structures have also begun to be applied in China.
Current status and latest progress in the application of seawater desalination membranes There are already reverse osmosis seawater desalination plants with a daily production capacity of 100000 tons abroad, and the single machine capacity of the large roll membrane seawater desalination plant currently in operation is 6000 tons per day. At present, the daily water production of reverse osmosis seawater desalination plants that have been built or are under construction in China is 350 to 1000 tons. The water utilization rate of single stage reverse osmosis seawater desalination in foreign countries is as high as 45%, while in China, it is mostly 35%. In addition, small membrane elements with a diameter of 2.5 inches are commonly used in reverse osmosis seawater desalination membranes loaded on domestic fishing vessels. At present, there are no more than 10 companies in China that produce seawater desalination units in bulk. The "sub seawater" desalination unit with a daily production capacity of 18000 tons built in Hebei is the largest reverse osmosis unit in China that uses seawater desalination membranes. In the future, the application of seawater desalination membranes in China will enter a new era, and in the near future, China will also build seawater desalination plants with a daily output of 10000 tons of water. In addition, commercial production of seawater desalination reverse osmosis membrane components has begun in China