The water used in Iran has a lot of benzoate, which causes many problems in the industry. Calcium and magnesium salts are among the major water impurities.
The excessive amount of these salts is not suitable for industrial, sanitary and edible water. Water hardness is the cause of sediment formation in boilers, heat exchangers, cooling towers, cooling systems, transmission pipes, etc. The most common way to remove water hardness is to use resin hardeners. The materials used in these hardeners are silica and resin.
In the hardening process in order to remove calcium and magnesium, the water passes through the bed of ion exchange resin that is inside the cylindrical and vertical tank.
It takes resin, calcium, magnesium and other water hardness and soft water comes out, As a result, the output water has a very low hardness. The resin in the hardener does not have an unlimited capacity, and before the resin is saturated, it must be regenerated by sodium chloride solution or crystallized salt. The task of the resin hardener is to convert precipitating solutions (calcium and magnesium) into non-precipitating solutions by ion exchange method.
The concept of water hardness
The water-soluble substances that have a sedimentary nature and are formed from the compounds of calcium and magnesium, strontium, aluminum, iron and manganese are called water hardness.
In natural waters, the concentration of calcium is usually about 2 times that of magnesium, while in sea water, the concentration of magnesium is about 5 times that of calcium in water. In general, water hardness can be classified into two parts: temporary or permanent.
temporary water hardness (carbonate hardness):
In fact, calcium and magnesium solutions are carbonate-free, which, due to heating, turn from soluble to insoluble, and as a result, turn into sediment.
permanent hardness (non-carbonate):
Calcium, magnesium sulfate, chloride, nitrate... solutions that do not precipitate due to heating. All natural waters contain different concentrations of dissolved salts, which are separated in water and create charged ions.
Ion exchanger
Ion exchange resins are solid particles that can replace undesirable ions in solution with the same amount of similar desirable ions. Artificial resins are aluminum silicate type that These are called zeolite resins which is found in nature as stones that can perform the work of synthetic zeolite. These materials remove water hardness ions (calcium and magnesium) and instead release sodium ions and hence are known as sodium zeolites.
Introducing the hardeners of Azar Dama Gostar company
Hardeners manufactured by Azar Dama Gostar company, based on decades of experience and following related standards in tank design and estimating the required capacity according to the customer's request, by its experienced forces, its hardener devices are marketed in capacities of 80 ~ 3000 K.gr. The hardeners produced by this company have three layers of sanitary epoxy paint, which makes them a suitable choice for sanitary purposes and standard engine room systems.
Important parameters in choosing a hardener:
Hardness of incoming water
Inlet water flow rate
Resin capacity
Time interval between two revivals
Amount of resin required
Compensation water percentage
Resin capacity
Boiler heat capacity
Classification of water hardness(ppm) Kind of water
0-75 light
75-150 relatively hard
150-300 Hard water
More than 300 So hard
Dos and don'ts of resin hardeners
In the design and implementation of ion exchange units, it should be noted that the cationic unit must be placed first Because the pH of the water is strongly alkaline and some cations are deposited on the anions and cause the destruction of the resins.
The stiffener should be installed on a suitable foundation (about 100 mm).
The incoming water must be free of chlorine, microorganisms, oil, iron and iron oxides. Activated carbon filters and sand filters can be used to solve these issues.
Because reviving and washing the hardener is time-consuming.
Because of that the system does not fail at the service time, it is recommended to use two hardeners (duplex) to service one of the hardeners and use the second hardener.
In order to properly manage the functioning of the hardening system, it is suggested to use a flow meter on the water supply pipe. (به منظور مدیریت صحیح بر نحوه عملکرد سیستم سختی گیر پیشنهاد می شود از یک دبی سنج بر روی لوله آب تغذیه آن استفاده شود.)
Setting up
After installing the device in the desired location, you perform the following steps.
Connect the inlet and outlet water pipes of the device to the system correctly.
Setup steps
1. First, close all the valves and open the ventilation valve of the device.
2. Set the Solo valve handle to the Run position.
3. Open the water inlet valve. In this case, the tank of the device is gradually filled with water.
4. As soon as the water comes out of the aeration pipe, close the aeration valve
5. Open the water outlet valve. In this way, the device is ready for operation and water purification.
How to inject resin and silica to hardener
First, wash the inside of the device with water to remove the dust and dirt inside the device. Then fill the tank with the right amount of silica, The depth of this layer inside the tank is 10 to 20 cm, Then pour the required amount of resin into the tank, which is estimated according to the hardness and flow rate of the water that needs to be hardened. Finally, pour a layer of silica 10 to 20 cm deep on the resin. Fill the salt tank according to the capacity of the device with the right amount of rock salt and then fill the tank with water so that the salt solution is available for resin regeneration. Then we seal the tank valves and carry out the start-up steps in order.
Maintenance
The hardness of the filtered water coming out of the hardeners should always be controlled and tested. As soon as the hardness of the water exceeds the permissible limit, it is necessary to immediately proceed to the action of regenerating the resin, which is described below.
The process of resin regeneration consists of three stages:
1. Backwashing to regenerate resins
2. Passage of the reducing agent through the resin bed.
3. Rinsing to expel the regenerating substance
1) Backwashing to regenerate resins
a. Put the handle of the Solo valve in the (BackWash) position
b. In this case, the water inlet and discharge is open and the water outlet and salt inlet is closed.
2) Passage of the reducing agent through the resin bed.
a. Put the handle of the solo valve in the position (Regeneration) and then open the valve of the salt tank.
b. In this case, the salt water inlet and discharge are open and the water outlet and water inlet are closed. if you open the brass cap on the salt nozzle, which is installed for this purpose behind the solo valve and next to the drain pipe, you can adjust the amount of suction with the help of a suitable screwdriver. The salt sucked from the salt tank regenerates the resin. At the end of this step, close the salt tank outlet valve.
3) Wash the resin with water
a. Put the handle of the Solo valve in the (BackWash) position.
b. In this case, the water inlet and discharge is open and the water outlet and salt inlet is closed. In this case, water enters the tank from the bottom of the resin column and is discharged from the top. This process causes the salt to be washed from the resins and its salinity is lost. This step continues until the water coming out of the tank drain loses its salinity. which takes about 20 minutes. To restart the cello valve system, we put it in Run mode, in this mode, the water inlet and outlet is open and the salt inlet and drain is closed.
Some recommendations for the optimal use of hardener
The concentration of salt for regeneration is about 8-12% and the flow rate of regeneration is also suggested and the amount of water used for regeneration is about 2 to 3 times the volume of resin.
If the hardener is out of service for a long time.
To avoid damage to the resins, the hardener should be filled with soft water completely regenerated in salt and the hardener should not be kept dry in any way.
The use of muddy water with suspended substances, as well as water containing iron, manganese, copper and other heavy metals, wears out the resins and reduces the hydration of the hardening device. Therefore, it is recommended that before entering the water into the device, suspended materials in the water are separated by a sand filter device and necessary measures are taken to reduce heavy metal salts.