Application scope of reverse osmosis pure water treatment: preparation of pure water and ultra-pure water in electronics, industry, medicine, food and other industries; purification and preparation of water for textile and chemical industries; purification and preparation of water for food and beverages and brewing process water; industry Useful substances and concentration and recovery of aqueous solutions in production; pre-desalination of high-pressure boiler feed water in power plants and other enterprises; desalination of brackish water and seawater; purified water device as a first-level desalination equipment for high-purity water production.
- The highest SDI of water intake (15 minutes) <5
- Maximum turbidity of influent water <1.0NTU
- Maximum free chlorine concentration in influent <0.1ppm
- Maximum temperature of inlet water <45℃
- The highest Fe content in influent water <0.05ppm
Reverse osmosis purified water process
Raw water tank → booster pump → mechanical filter → activated carbon filter → automatic water softener or dosing device-precision filter → high pressure pump → reverse osmosis device
Raw water tank
Function: Overcoming the instability of the water supply of the pipe network, ensuring the stable and continuous water supply of the entire system; at the same time, it also provides a guarantee for the long-term reliability of the equipment.
Selection: PE material or stainless steel water tank.
Control: The water tank is equipped with a high-water level float valve and a low-water level switch. It has the advantages of high reliability, low price, simple structure and convenient installation. When the water level is at a high level, the float valve is closed to stop water inflow. When the water level is at a low water level, the high water level float valve opens and starts to fill the water tank. At the same time, the low water level switch is turned off and the booster pump stops working.
Function: Provide necessary working pressure for pretreatment equipment.
Selection: Determine the working pressure of the booster pump according to the design pressure drop of each pretreatment device (the maximum pressure drop of each filter device is 0.05Mpa), and the pressure before the high-pressure pump cannot be less than 0.5Kg/cm2.
Control: Use a regulating valve after the pump to adjust the pressure and water intake.
Function: The raw water first passes through a mechanical filter, and 12-24 mesh fine quartz sand is placed in the filter, so that the flocs, rust and other suspended impurities in the raw water are intercepted in the process. Since the mechanical filter retains a large amount of suspended impurities during operation, in order to ensure the normal operation of the filter, the filter must be flushed and backwashed regularly.
Selection: Use FRP material (glass reinforced plastic) container.
Control: The backwash operation of the mechanical filter adopts a manual controller. The filter should be cleaned once a day, and the cleaning time is 10-20 minutes.
Function: This process adopts activated carbon filter, which is very important as the pretreatment of reverse osmosis device. The reverse osmosis system requires the inlet water index SDI≤5, and the residual chlorine <0.1mg/L. In order to meet its water intake requirements, the raw water needs to be further purified to achieve the reverse osmosis water intake index. A carbon filter is installed in front of the reverse osmosis device, which has two main functions: 1. It absorbs some organics in the water with an adsorption rate of about 60%; 2. It absorbs residual chlorine in the water. It absorbs inorganic colloids, organic colloids and soluble organic polymer impurities with a particle size of about 10-20 angstroms, as well as residual chlorine that is difficult to remove in a sand filter. The reason why activated carbon can be used to adsorb active materials with a particle size of about tens of angstroms is that its structure has a large number of micropores and gaps with an average pore diameter of 20-50 angstroms. This structural feature of activated carbon makes its surface adsorption The area can reach 500-2000m2/g, because the molecular diameter of general organic matter is slightly less than 20-50 angstroms, so activated carbon has a strong adsorption effect on organic matter. In addition, activated carbon has a strong dechlorination ability. Because the residual chlorine has strong oxidizing properties, the residual chlorine reacts with carbon to generate carbon dioxide and -1 valent chloride ions, so only a small amount of carbon is lost, so the activated carbon is dechlorinated It can be used for a long time. Activated carbon not only has the above functions, but also can remove the peculiar smell and pigment in the water, and improve the clarity of water. After the activated carbon is used for a period of time, its adsorption capacity decreases and needs to be regenerated or replaced. Therefore, after the raw water passes through the carbon filter, the water quality can be greatly improved, and the pollution of the reverse osmosis membrane can be reduced. After the treatment, the water quality can meet the water quality requirements of the reverse osmosis device (residual chlorine <0.1mg/L).
Selection: Use glass fiber reinforced plastic container with an expansion rate of 40%.
Control: The activated carbon filter is controlled by a manual controller. Because the activated carbon filter absorbs a large amount of suspended impurities during work, in order to ensure the normal operation of the system, it must be flushed and back flushed every day. The flushing process is 15- 30 minutes.
Function: The process of removing the hardness (Ca2+, Mg2+) in the water is called softening. The equipment is filled with 001×7 strong acid Na ion exchange resin, and sodium ions are used to replace calcium and magnesium ions in the raw water, so that the residual hardness of the raw water is less than 0.03mmol/L. The purpose of softening is to prevent scaling on the surface of the reverse osmosis membrane, so as to extend the service life and treatment efficiency of the reverse osmosis membrane.
Selection: The water softener is made of glass fiber reinforced plastic container,
Control: The control system adopts American automatic control valve type. According to the set time/flow, the control valve head can automatically regenerate the resin, complete the salt absorption backwash, and the positive flushing and water injection process. The water softener is equipped with a regeneration tank. The amount of salt and water in the salt tank should be checked daily, and the salt should be refilled in time (the use of iodized salt and other salt with additives is prohibited).
Function: Precision filtration is also called security filter. It is a treatment process before raw water enters the reverse osmosis membrane device. The PP filter element has the characteristics of large filtration flow, large dirt holding capacity, and small pressure loss. It can block foreign particles of different particle sizes and integrate surface filtration and deep filtration. The precision filter is also clogged after a certain period of use. Therefore, the PP melt blown filter element must be replaced after a certain period of time. The replacement basis: the pressure difference before and after the precision filter is replaced when the pressure difference is 0.05-0.1Mpa.
Selection: use stainless steel container.
Function: The high-pressure pump is to provide the working pressure of the water flow and water quality required by the reverse osmosis system. After the filtered water passes through the pump body, it reaches a pressure of about 10 kg to meet the inlet pressure of the membrane body and ensure the output of pure water.
Selection: According to the working pressure required by the reverse osmosis membrane, a Grundfos vertical multi-stage high-pressure pump is used.
Control: When the raw water pressure gauge pointer reaches 2KG, press the water production switch, the high-pressure pump starts, and water production starts. There is a pressure protection switch in front of the high-pressure pump. When the inlet water pressure is lower than 1KG, the pressure protection switch is closed and the high-pressure pump stops working.
Function: The reverse osmosis device is the main part of the purified water production line. This device uses the energy-saving composite membrane ESPA type reverse osmosis membrane element produced by Japan’s Nitto Denko Group and the United States Hyde Energy Company. ESPA series are brackish water desalination membranes with high desalination rate. It can obtain high water flux under lower operating pressure, and its average salt rejection rate is 99.5%.