Process flow-working principle of water softening equipment I. Working principle of water softening equipment Since the hardness of water is mainly formed and expressed by calcium and magnesium, cation exchange resin (water softener) is generally used to convert Ca2 + and Mg2 + in water (to form The main component of scale is replaced. With the increase of Ca2 + and Mg2 + in the resin, the effectiveness of the resin to remove Ca2 + and Mg2 + gradually decreases.
After the resin absorbs a certain amount of calcium and magnesium ions, it must be regenerated. The regeneration process is to rinse the resin layer with the saline solution in the salt tank, replace the hardness ions on the resin, and the resin is discharged out of the tank with the regeneration waste liquid. The softened exchange function was restored.
Because the hardness of water is mainly formed by calcium and magnesium, and because the hardness of water is mainly formed by calcium and magnesium, and the principle of softening treatment of sodium ion exchange is to pass raw water through a sodium-type cation exchange resin, the hardness components Ca2 + and Mg2 + The Na + phase in the resin is exchanged to adsorb Ca2 + and Mg2 + in the water and soften the water. If RNa is used for sodium resin, the exchange process is as follows:
2RNa + Ca2 + = R2Ca + 2Na +
2RNa + Mg2 + = R2Mg + 2Na +
That is, after water passes through a sodium ion exchanger, Ca + and Mg + in the water are replaced with Na +.
The general operation process of the control valve is: operation, backwash, salt absorption, slow washing, salt tank water replenishment, and forward washing.
Selection of softening water equipment
1. First, you need to provide what kind of system you need to use demineralized water:
1) Heating 2) Cooling water supply 3) Process water 4) Steam boiler 5) Steel smelting industry 6) Chemical and pharmaceutical industry
2. System water use time:
I.e. run time / hour water consumption / average value / peak value /
Does the equipment require continuous water supply? If necessary, select the double-bed centralized control or double-control double-bed series, otherwise select the single-valve single-tank series.
3. Total hardness of source water The source of water is municipal tap water \ groundwater \ surface water, and the total hardness of the raw water in the area. For a certain type of water softener, the hardness of the raw water is high, and the periodic water production volume must be relatively reduced, which results in frequent regeneration of the water softener. Relatively reduce the service life of the resin. To avoid such situations, the volume of the resin should be increased, which means that a larger type of water softener is used.
4. The required soft water unit flow rate (ton / hour).
This depends on the nature and requirements of the user equipment;
5. Setting of the periodic water production capacity After setting the model of the water softener, according to the hardness of the raw water, the exchange working capacity of the resin used can determine the theoretical periodic water production capacity (tons).
Third, the controller type of softened water equipment
This method is the traditional standard method, which mainly has two forms of forward flow / no top pressure counter current. Generally, two carbon steel tanks are connected in parallel. According to different technological processes, each tank needs to be equipped with 8-11 Manual valve (two tanks need to be equipped with about 16-20 valves), and the salt solution is pumped into the resin tank with a special salt pump during regeneration (this kind of equipment was the main form of domestic water softening equipment). The main features of this type of softened water equipment are: the process is simple, easy to understand, easy to operate, low cost, and suitable for the needs of large flow; , The salt pump is severely corroded and has high maintenance costs. 2.Domestic combination automatic type:
Because the use of manual equipment is too complicated, in the early 1990s, a new type of equipment with a combined integrated valve as its core appeared in China. The main core component of this equipment is a multi-channel integrated valve, which changes the direction of water flow through the rotation of the valve body. Compared with traditional manual equipment, this kind of equipment occupies a much smaller area and has a higher degree of automation than traditional manual equipment. But because the control method uses time control, the control accuracy is lower during operation. Limited by design ideas, processing techniques and materials, the planar integrated valves used by most equipment are prone to wear and tear, and once repaired, the possibility of repair is very small. At present, there are many manufacturers of such equipment in the domestic market, and the actual quality of the products varies greatly, and the operation results of many equipment are not satisfactory.
3.Imported automatic type In European and American countries, automatic design of ion exchange equipment has been started since the 1960s. With the development of industrial technology, multi-way valves and integrated valves that are different from domestic multi-port valves have gradually developed Multi-way valves are mainly used. The main materials are engineering plastics and lead-free brass. Its core component is a multi-channel integrated valve. Generally, a valve plate or a piston is used to control the direction of water flow. A small motor drives a camshaft (or piston) to operate. Due to the development of foreign industrial technology, this type of equipment has been developed quite well. The product specifications range from 0.2t / h for domestic use to 70t / h for industrial use. The controller has a high degree of automation (the latest one can Computer or general surveillance computer communication).
4.Fully-automatic discrete valve:
Discrete valves are generally imported imported fully automatic diaphragm valves or solenoid valves, adopting a structure similar to the traditional manual method, and combined with a dedicated fully automatic controller (Single Chip Microcomputer or PLC) to form a water softening device. Full-automatic equipment is mainly used for the occasions with large flow, and can also be used for the transformation of traditional manual equipment. The traditional manual equipment can be transformed into automated equipment without changing the original equipment pipeline. Thereby reducing the operating labor intensity and equipment consumption.