Raw water → raw water booster pump → multi-media filter → activated carbon filter → water softener → precision filter → cation resin filter bed → anion resin filter bed → anion resin mixed bed → microporous filter → water point.
Intermittent ion exchange
This operation mode is to mix the ion exchange resin with the raw water to be treated and stir it properly, so as to basically achieve the exchange balance and make the balanced water quality meet the design requirements. This method is usually used for small-scale production or experimental needs.
Fixed bed ion exchange
It is one of the most commonly used ion exchange methods. The ion exchange resin is placed in an exchange column, and the treated raw water flows through the resin bed at a certain flow rate to achieve the exchange purpose. The method has simple equipment and convenient operation, and is suitable for production of various scales, but the resin utilization rate is low and the regeneration cost is high. The process is as follows:
Raw water → raw water booster pump → multi-media filter → activated carbon filter → water softener → precision filter → primary reverse osmosis →PH adjustment → intermediate water tank → secondary reverse osmosis → pure water tank → pure water pump → microporous filter → water point. Advantages of EDI ultra-pure water equipment technology
EDI ultra-pure water equipment is widely accepted by pharmaceutical industry, microelectronics industry, power generation industry and laboratories. It is also widely used in surface cleaning, surface coating, electrolysis industry, chemical industry and solar photovoltaic industry.
EDI can replace the traditional mixed ion exchange technology (MB-DI) to produce stable deionized water. Compared with mixed ion exchange technology, EDI technology has the following advantages:
The dosage of 1. ion exchange resin is small, which is about 5% of the traditional ion exchange method.
2. The ion exchange resin has no acid-base chemical regeneration, which saves a lot of acid, alkali and cleaning water and greatly reduces the labor intensity.
3. No waste acid or alkali liquor is discharged, which is a clean production technology and an environmental protection product.
4. The process is easy to realize automatic control, and the quality of the produced water is stable. Combined with RO and other water treatment technologies, a perfect production line of pure water and ultrapure water can be formed.
5. The quality of produced water is high, which can reach the national first-class standard of electronic grade water. The resistivity is15 ~18mΩ cm, and the bacterial endotoxin content is less than 0. 1mg/L, which can completely meet the requirements of China Pharmacopoeia and American Pharmacopoeia for pharmaceutical water.
6. Excellent ability to remove weakly dissociated substances (such as carbon dioxide, silicon, boron, ammonia, etc.). ), which is more suitable for the demand of ultra-pure water.
7. The production process of pure water is continuous, and there is no need to repeatedly set one set in use and one set in regeneration like an ion exchange bed.
There are not many manufacturers specializing in EDI ultra-pure water equipment in China, and the EDI ultra-pure water equipment produced by Huitongyuan Environmental Protection Technology is the leader in this industry. Huitong source cooperates with many large domestic enterprises, such as pharmaceutical industry, microelectronics industry and chemical industry. Among them, customers are Shenzhen Huimin Pharmaceutical Co., Ltd., Shenzhen Kairuilin Technology Co., Ltd., Dongguan Yisheng Battery Co., Ltd., Shenzhen Meijing Metal Products Co., Ltd. and Shenzhen Daniel F. Akerson Automation Equipment Co., Ltd.. We all provide EDI ultra-pure water equipment. Our company hopes that the technology in this field can be recognized by more customers, thus further promoting the importance of EDI technology in the development of water treatment industry.
The working principle of EDI
EDI module (membrane stack) is the core of EDI work. A simple EDI membrane stack is mainly composed of two electrodes with opposite electrical properties and a plurality of module unit pairs. A membrane unit pair consists of a fresh water chamber (chamber D), a positive membrane, a negative membrane and a concentrated water chamber (chamber C) filled with cation exchange resin and anion exchange resin. EDI membrane stack contains multiple membrane unit pairs. There are two electrodes with 600V voltage inside each membrane stack, which is the voltage required to pass through each membrane stack. The positive electrode has a positive voltage and the negative electrode has a negative voltage, and the current passes through 30 membrane units between the positive electrode and the negative electrode. Any fresh water room contains cation resin and anion resin, which is equivalent to 8 km thick mixed bed. The positive diaphragm separates the fresh water chamber from the concentrated water chamber towards the cathode, and the negative diaphragm also separates the fresh water market from the concentrated water chamber on the other side. The membranes used in EDI are very different from those used in reverse osmosis. The membrane used for reverse osmosis allows small particles of molecular pollutants, ions and water to pass through, while EDI membrane, like ion exchange resin, is made of polystyrene, and only ions with appropriate charges are allowed to pass through, but water can hardly pass through. Resin is continuously regenerated through the separation of water.
In the electric field, water molecules in the feed water are separated into H+ and OH-, which are attracted by opposite charges. H+ moves towards the cathode through Yang Yang resin, and OH- moves towards the anode through anionic resin. The migration of H+ and OH- regenerates the resin. The positive membrane allows H+ to enter the concentrated water chamber, while the negative membrane allows OH- to enter the concentrated water chamber, and H+ and OH- combine to produce water. The water flow in the concentrated water chamber will take away the anions and cations in the water. The membrane prevents ions with opposite charges from entering the fresh water chamber. In the process of water flowing through the fresh water chamber, ions are removed by the resin, so the effective side of the membrane (fresh water chamber) will produce pure water.
The operation process is as follows:
Raw water → raw water booster pump → multi-media filter → activated carbon filter → water softener → precision filter → primary reverse osmosis host → intermediate water tank → intermediate water pump →EDI system → microporous filter → water point.