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Reverse osmosis technology is the most advanced and most energy-saving and effective membrane separation technology today. The principle is that under the action of higher than the osmotic pressure of the solution, other substances cannot pass through the semi-permeable membrane and these substances and moisture are removed. Because the membrane pore size of the reverse osmosis membrane is very small (only about 10A), it can effectively remove dissolved salts, colloids, microorganisms, organic matter, etc. in the water (removal rate as high as 97%-98%). Reverse osmosis is currently the most widely used desalination technology in high-purity water equipment. Its separation object is organic matter with a range of ions and a molecular weight of several hundred in the solution; reverse osmosis (RO), ultrafiltration (UF), microporous membrane filtration (Both MF) and electrodialysis (EDI) technologies are membrane separation technologies.
The priority design point of a reverse osmosis system is related to the required water volume and other parameters, and is also restricted by the characteristics of the reverse osmosis membrane element and the raw water. For example, from the perspective of insoluble salt and colloidal pollution, the recovery rate of a multi-stage reverse osmosis system may reach 88%. Even if the single membrane element process system does not scale and there is no problem with SDI3.0-5.0, the system recovery rate is still 15%.
On the other hand, the seawater desalination system only has a recovery rate of 30-45% (multiple membranes in series), mainly because of the high osmotic pressure of the concentrated water. Generally, the highest operating pressure of seawater membrane elements during long-term operation is about 69bar. The highest recovery rate of a single seawater membrane element is only about 10% (SDI<5).
In the seawater system, even at the highest allowable pressure, the permeate water volume is relatively low, while in the brackish water system, even if the 41bar operating limit is not reached, the permeate flow rate will be high. Although it is tempting to increase the permeate flow rate in order to minimize the cost of membrane elements, in order to prevent pollution and scaling, this flow rate must be limited. For example, the flow limit in the system design depends on the pollution trend in the inlet water.
Qinhuang Water RO water machine uses the most advanced DuPont ion membrane in the world. High purity water can filter 99.999% of bacteria, fungi and microorganisms. Ensure the user's health and safe drinking water.
