Deionized water equipment is an ion exchange system. Ion exchange system is a traditional water treatment process in which various anions and cations in water are replaced by anion and cation exchange resins. Ion exchange cation bed system, anion exchange anion bed system and ion exchange mixed bed system can be formed by mixing anion and cation exchange resins in different proportions, And the mixed bed system is usually used in reverse osmosis and other water treatment processes to produce ultra pure water, high pure water terminal process, it is used to prepare ultra pure water, high pure water is one of the irreplaceable means.

Basic introduction

The conductivity of the effluent can be lower than 1US / cm, and the resistivity of the effluent can reach 1m Ω. According to different water quality and application requirements, the effluent resistivity can be controlled within 1 ~ 18m Ω. Cm. It is widely used in the preparation of ultrapure water and high purity water for industries such as electronics, electric power ultrapure water, chemical industry, electroplating ultrapure water, boiler make-up water and pharmaceutical ultrapure water.  [ 1]   working principle

The cation and anion in water can be removed by ion exchange method, and sodium chloride (NaCl) represents the inorganic salt in water. The basic reaction of water desalination can be expressed by the following equation:

1. Cation exchange resin: R-H + Na + r-na + H+

2. Anion exchange resin: R-OH + cl-r-cl + OH - cation, the total reaction formula of anion exchange resin can be written as: RH + Roh + NaCl - RNA + RCL + H2O

It can be seen that the NaCl in the water has been replaced by H + and oh - on the resin respectively, and the reaction product is only H2O, so the salt in the water can be removed.

New technology

According to the application industry, the process of deionized water equipment is different. Here we take the preparation process of ultrapure water for cleaning coated glass lenses as an example

1. Pretreatment → reverse osmosis → intermediate water tank → water pump → EDI device → purified water tank → pure water pump → ultraviolet sterilizer → polishing mixed bed → precision filter → water object (≥ 18m) Ω. Cm) (latest process)

2. Pretreatment → primary reverse osmosis → dosing machine (pH regulation) → intermediate water tank → secondary reverse osmosis (positive charge reverse osmosis membrane) → pure water tank → pure water pump → EDI device → ultraviolet sterilizer → precision filter → water object (≥ 17m) Ω. Cm) (latest process)

3. Pretreatment → reverse osmosis → intermediate water tank → water pump → EDI device → pure water tank → pure water pump → ultraviolet sterilizer → precision filter → water object (≥ 15m) Ω. Cm) (latest process)

Equipment technology

Deionized water can be divided into four processes

The first one is the deionized water obtained by Cation Anion exchange resin. Generally, after passing through, the effluent conductivity can be reduced to below 10us / cm, and then it can reach below 1US / cm through the mixed bed. But the cost of water produced by this method is very high, and there are too many impurities in the particles, which can not reach the reasonable level

I want to meet your requirements. It has been less used.

Second: pretreatment (i.e. sand carbon filter + precision filter) + reverse osmosis + mixed bed process

This method is the most widely used at present, because the investment cost of reverse osmosis is not high. More than 90% of ions in water can be removed, and the remaining ions can be removed by mixed bed exchange, so that the effluent conductivity is about 0.06. This is the most popular method at present.

The third is two-stage reverse osmosis

The process is as follows:

Tap water → multi-media filter → activated carbon filter → water softener → intermediate water tank → low pressure pump → precision filter → primary reverse osmosis → pH regulation → mixer → secondary reverse osmosis (reverse osmosis membrane surface with positive charge) → pure water tank → pure water pump → microporous filter → water consumption point

Fourth: reverse osmosis is used for pretreatment as the second method, but EDI continuous desalting membrane block is used to replace the later mixed bed, so that the acid-base regeneration resin is not used, but electric regeneration is used. This completely makes the whole process pollution-free, and the water quality after treatment can reach more than 15m. However, this method has a lot of initial investment and low operation cost. Make appropriate investment according to the situation of each company. The best. The process is as follows:

Raw water → multi medium filter → activated carbon filter → water softener → intermediate water tank → low pressure pump → pH value regulating system → high efficiency mixer → precision filter → high efficiency reverse osmosis → intermediate water tank → EDI pump → EDI system → microporous filter → water consumption point

Process characteristics of equipment

Ion exchange equipment is a traditional deionized water equipment, its water quality is stable, the cost is relatively low. In the past, the boiler make-up water in power plant was treated by cation bed + anion bed + mixed bed.

With the development of reverse osmosis, EDI and other processes, the operation of ion exchange equipment is complex, not easy to realize automation, waste acid and alkali, high operating cost and other shortcomings are more prominent, and it is more used in the advanced treatment of reverse osmosis.

Small ion exchange equipment often uses plexiglass exchange column, which is helpful to observe the operation of resin. For example, whether the regeneration stratification of mixed ion exchanger is sufficient, whether the cation is "poisoned", and the loss of resin.

For large ion exchange equipment, carbon steel is lined with epoxy resin or rubber, and a visual device is reserved in the middle, so as to observe the water level of regeneration liquid online during ion regeneration.

application area

1. Industrial ultra pure water treatment process is one of the most widely used processes in the preparation of industrial ultra pure water.

2. In food industry, ion exchange resin can be used in sugar, monosodium glutamate, wine refining, biological products and other industrial devices.

3. Ion exchange resin in pharmaceutical industry plays an important role in developing new generation of antibiotics and improving the quality of original antibiotics. The successful development of streptomycin is a prominent example.

4. In synthetic chemistry and petrochemical industry, acids and bases are often used as catalysts for esterification, hydrolysis, transesterification and hydration.

5. Metal ions in electroplating wastewater, recovery of useful substances in film making wastewater, etc.

6. Hydrometallurgy and other ion exchange resins can separate, concentrate, purify uranium and extract rare earth elements and precious metals from depleted uranium ore.