Mixed bed system

The mixed bed ion exchange method is to place the anion and cation exchange resins in the same exchanger and mix them evenly before running, so it can be seen as a multi-stage compound bed with countless anion and cation exchange resins staggered. The anions and cations of the salts in the water pass through the exchanger and are exchanged by the resin to obtain highly pure water.

 

At present, it is one of the irreplaceable means for preparing ultrapure water and high purity water. The effluent conductivity can be lower than 1uS/cm, and the effluent resistivity can reach more than 1MΩ.cm. According to different water quality and usage requirements, the effluent resistivity can be controlled between 1~18MΩ.cm. It is widely used in the preparation of industrial ultra-pure water and high-purity water such as electronics, electric power ultra-pure water, chemical industry, electroplating ultra-pure water, boiler feed water and medical ultra-pure water.

 

In the mixed bed, since the anion and cation resins are mixed with each other, the anion and cation exchange reactions are carried out almost at the same time. The H+ and OH- generated by OH-type exchange cannot be accumulated, basically eliminating the influence of counter ions, and the exchange is more thorough.

 

Since the primary pure water entering the mixed bed is better, the load of the exchanger is light, and the exchange capacity of the resin takes a long time to be exhausted. The mixed bed adopts the internal regeneration method. During regeneration, the specific gravity of the two resins is different first, and the anion and cation exchange resins are completely separated by backwashing, the cation resin is deposited on the bottom, and the anion resin floats on the top. The anion exchange resin is regenerated with caustic soda.

1. Regeneration device: the anion exchange resin regeneration alkali solution is fed into the mother tube at a position 300 mm higher than the surface of the anion exchange resin (Φ400, 500, 600 use a single mother tube to enter the liquid, Φ800, 2500 use a double mother tube to enter the liquid), the pipe The upper small hole cloth liquid is used, and the outside of the pipe is covered with plastic window screen 60 mesh nylon mesh cloth, and the regenerated acid of the cation exchange resin enters from the drainage cap on the perforated plate of the bottom drainage device.

 

2. Middle row device: The middle row device is set on the interface between the yin and cation resins, and is used for regeneration and excretion of acid, alkali reduction solution and flushing type. Cover with one layer of plastic window screen and 60 mesh nylon mesh.

 

3. Drainage device The PB2-500 laminated drainage cap or pagoda-type ABS drainage cap is installed on the perforated plate. The material of the perforated plate varies according to the specifications of the equipment.

 

4. The diameter of the water inlet and outlet pipes is 1.5 m/s according to the flow rate of the working medium in the pipe.

 

5. Resin backwash expansion rate: Since the backwash expansion rate of anion exchange resins is different, combined with the actual operation experience, the backwash expansion rate is * *. One sight glass is installed at the expansion height to observe the resin surface and backwash the resin.

 

6. Conveying of resin: The input and discharge of resin are considered to adopt hydraulic conveying. The upper part of the cylinder is provided with a resin input port, and a resin discharge port is provided at the lower part of the simplified structure near the porous plate.