Yin bed and Yang bed

The softener is a sodium ion exchanger, which can be divided into various types such as sodium ion exchangers, anion and cation beds, and mixed beds. The shell of ion exchange columns (devices) is generally made of materials such as rigid polyvinyl chloride (PVC), rigid polyvinyl chloride composite fiberglass reinforced plastic (PVC-FRP), organic glass (PMMA), organic glass composite transparent fiberglass reinforced plastic (PMMA-FRP), steel lined rubber (JR), stainless steel lined rubber, etc. It is mainly used for pre-treatment of boilers, thermal power plants, chemical, light industry, textile, pharmaceutical, biological, electronic, atomic energy and pure water treatment. It is also used in industrial production for hard water softening and deionized water preparation. It can also be used for decolorization and purification of food and drugs, recovery of precious metals and chemical raw materials, and treatment of electroplating wastewater.

A mixed bed is a process of packing anion and cation exchange resins in a certain mixing ratio into the same ion exchanger. As the H ions and OH ions entering the water after mixed ion exchange immediately generate water molecules with low ionization degree, the exchange reaction can proceed very thoroughly. Mixed beds are generally set up after the first stage double bed for further purification of water quality. When the water quality requirements are not high, it can also be used separately.

The organic glass ion exchange device is corrosion-resistant, colorless and transparent, suitable for small-scale pure water preparation in the food, pharmaceutical, sugar and electronics industries. The carbon steel lined rubber ion exchange device has the characteristics of large water production capacity, high strength, and low cost, and is suitable for large-scale boiler softened water and large-scale pure water preparation.

Cation bed, also known as cation exchanger, is an important component of the pre-treatment and water purification system for pure water preparation. The material can be made of steel lined rubber or stainless steel, and is divided into natural quartz sand filters, multi-media filters, activated carbon filters, manganese sand filters, etc. according to the different filtering media. It can be divided into single flow filters and double flow filters according to the water inlet method, and can be used in combination or separately according to the actual situation. The medium of the multi-media filter is quartz sand, anthracite, etc. The function is to filter out suspended solids, mechanical impurities, organic matter, etc., and reduce the turbidity of water. The medium of the activated carbon filter is activated carbon, which aims to adsorb and remove pigments, organic matter, residual chlorine, colloids, etc. from water. The medium of the manganese sand filter is manganese sand, which mainly removes divalent iron ions from water.

The pipeline of the single flow mechanical filter is simple and runs smoothly. The filtration flow rate is generally 4-50m/n, and the operating cycle is generally 8 hours. The dual flow mechanical filter is equipped with inlet devices at both ends and outlet devices in the middle. Its advantages are a large amount of filtered water, high pollutant removal capacity, and long operating cycle, usually 20 hours. The disadvantage is that the pipeline system is complex, the operation is not very stable, and it is difficult to flush and replace materials.

Process flow of counter current regeneration without top pressure in a cation bed

Exhaust → small backwash → large backwash (only used after ten cycles of operation, small backwash once before each large backwash to loosen the grease layer) → water discharge → pre injection → acid injection → displacement → exhaust → small positive wash → large positive wash