Water softener is one of the water treatment methods in which the cationic resins and, the temporary hardness of the water is reduced, and Soft water had been produced. Soft water is used in the boiler, heat exchanger, cooling tower, and the production of various detergents and other industrial uses.
In the water softener system, calcium and magnesium ions are exchanged with resins and with sodium in the cationic resin bed. During this process, the Total Hardness is reduced. Total Hardness is the main cause of the sedimentation on the high-temperature heat exchanger tubes, which, in addition to the problem of obstruction, reduce the efficiency of the equipment and increase the cost of energy.
TARHOKAR Engineering Company works in the field of the production of a variety of water softener system cassettes to produce water (soft) by the most reputable brands of cationic softener resins including UK PUROLITE and USA Amberjet. They are designed, manufactured, installed or initiation for various types of water.
Expansion of the water purification process by cationic softener in a water softener system; exchange of ions by cationic resins to remove water hardness. Water refers to the concentration of calcium and magnesium ions in terms of CaCO3 lit / mg. As a result of the crossing the water from a water softener system, calcium ions and magnesium in sodium water in the cationic resin exchanges, in the form that both the solution and the resin are kept altogether neutral in terms of electrically. The exchangers have this feature, which is only one of two ions, movable and interchangeable.
As an example, a cationic resin has non-mobile anionic points that are attached to moving cations such as Na (or) hydrogen.
In this way, an anion exchange has an immovable cationic point where mobile anions such as (Cl) or (OH) hydroxyl chloride are attached to it.
In a water softener system, the hard water passes from the way of ion exchange resins inside the cylindrical and vertical reservoir is interspersed in order to remove the calcium and magnesium. The cationic ion exchange resin displaces its existing sodium from calcium and magnesium in the water. So that the water flows from the bed of the resin softened and instead it contains sodium ion. In this situation, calcium and magnesium are inside the resin.
The cationic resin in a water softener system does not have an unlimited capacity, and before resin saturation is usually between 8 and 21 hours required. Resins need to be regenerate with a salt solution should be performed.
The recovery process of the water softener system in a water treatment unit consist of backwash is the resurrection by water, salt and final rinsing. This operation takes about 1 until 2 hour, and the cationic column has been prepared for soft water production again.
As explained in the description of the water treatment process, the capacity of the cationic ion exchange resins used for tampering is not unlimited. The total capacity of a water softener system based on the volume of the resin capacity is named Grain unit. Usually, a unit with 330 liters of grains is 330.000.
As explained, there is an organic branch in the resin hardening structure which attaches to Sodium. When water which is contained of calcium and magnesium (hard water) is placed in contact with a cationic softening resin in, two-volume calcium and magnesium ions are replaced by a higher load than sodium on the resin level, and As a result, sodium enters to the water. That is, the exchange of ion exchange is attributed to this exchange. As a result of this, the capacity of the cationic resins is gradually saturated and is required to be restored by water and salt.
In fact, the water softener system is being reintroduced in the recovery process of sodium ions replaced with calcium and magnesium. It should be noted that, it is necessary to back wash in the bed of hardening to expel the suspended particles, the dust or particles which are trapped in the cationic resin.
In the next level, the regeneration occurs by the water and salt at 10%.
At this step, the reduction is adhered to the water softener resin chain due to the high concentration of sodium ion, and calcium and magnesium are detached.
After the regeneration operation, the water softener system is rinsed several times to prepare for the softening process. Regeneration and backwash process Cationic softening takes about 0 to 2 hours in a water treatment package.
Resins in a water Softener system form the most important part of the water purification process. These resins are made of polyester-bonded with DVB and in the spherical shape. Some specifications of these resin cationic softening packages are as below:
Polymer structure: polyester found with DVB
Physical shape: spherical
Total capacity in equivalent in Liters: 1
Resin size: 1000 microns
The Resins which is used in the cationic softening kit for marking water are marketed by UK PUROLITE (DOW)
Other types contain the anionic chloride resin, anionic hydroxide resin, hydrogen cationic resin, which is used in other water refinery process such as ion exchange (bed Mixed).
Because the cationic softening resins are used in a water-disinfectant package to exchange the ion in a rigorous formulation, the presence of suspended particles and water turbidity prevents this exchange.
The presence of microorganisms or oxidizing agents such as free chlorine or ozone in the intake water would also lead to degradation of the hardening level. Therefore, disinfection and filtration operations (often sand filters) must occur before entering the cationic water Softener system and eliminating oxidizing agents.
The most prominent use of cationic softening in the water treatment industry, as its name suggests, is the removal of temporary water hardness. This application, although very limited to certain ions in water, but in practice purifies most of the sedimentation factors in high-temperature water used in industries. The most important application of the water Softener system in the industry is the following:
1- in the makeup water of the boiler in order to remove the hardness and reduce the sedimentation on the boiler.
2- in the water purifier of the cooling tower to prevent the water from depositing on the heat exchanger plates.
3- Heat exchange equipment used as a cooling or heat transfer agent to reduce heat stress.
4- In detergent industries for the production of products such as shampoo and the gel of the hair, and also detergent powder which leads to quality drop.
The most notable limitation of the cationic hardening package is the increase in salinity or water TDS due to the exchange of ions with sodium. Indeed, the contained sodium in the resin enters the treated water and boosts the salinity of the water.
Other problems of water treatment by water Softener system are high amounts of highly salty wastewater, a very high operator and no alkalinity adjustment Outlet water.
In the article of comparing the water Softener system and reverse osmosis method, some of the limitations of this water treatment method are shown.