1、 Overview of cation exchanger
This product is currently an advanced and practical product in ion exchangers. It has changed the original fixed bed co current regeneration process to counter current regeneration and is designed for non top pressure regeneration, which not only saves losses but also omits the gas source for the gas top. After treatment with a sodium ion exchanger, the total hardness of the water decreases to below 0.04 milliequivalents per liter. When treating water with high total hardness or requiring low effluent hardness, a two-stage series softening method can be used.

2、 Working principle
A certain height of sodium ion exchange resin is installed inside the sodium ion exchanger as the exchange agent. Raw water passes through the exchanger layer from top to bottom, and the sodium ions on the exchanger replace the calcium and magnesium ions in the raw water, causing the water to soften. The reaction is as follows:

Ca2++2NaR → CaR+2Na+
Mg2++2NaR → MgR+2Na+

The sodium ions on the exchange agent are gradually replaced by calcium and magnesium ions. After a period of use, calcium and magnesium ions will leak out. When the hardness of the effluent reaches the specified value, the operation will stop and regeneration will be carried out. During regeneration, 5-8% saline (or dilute hydrochloric acid) is passed through the exchanger layer from bottom to top. The sodium ions in the salt solution replace the calcium and magnesium ions on the exchange agent, regenerating the exchange agent and restoring its exchange capacity. The reaction is as follows:
CaR+2Na+→ Ca2++2NaR
MgR+2Na+→ Mg2++2NaR

3、 Structure Overview

1. Inlet device
A water inlet device is installed at the top of the equipment to evenly distribute water on the exchange layer.

2. Middle row device
The middle row device is set at the interface between the ion exchange resin layer and the pressure layer, used to discharge regenerated salt waste liquid and feed small backwash water. The types are: DN500-N600 type is double main pipe type, DN800-N3200 type is branch main pipe type, and the material is stainless steel 316L wedge-shaped wire winding.

3. Drainage system
Equipment with a diameter of DN1200 and below shall be equipped with a water filter cap on a porous plate, which shall be made of steel porous plate.
In addition, one sight glass is installed at the lower drainage cap, resin surface, and backwash expansion height of the exchanger to observe the working conditions inside the body. Considering the hydraulic loading and unloading of resin, a resin input port is provided at the upper part of the cylinder, and a resin discharge port is provided near the porous plate at the lower part of the cylinder.

4、 Usage method

1. Resin treatment
After soaking for 4 hours, drain the salt water and rinse the resin with water until the water no longer turns yellow. Alternatively, the resin can be dissolved in 5% HCL and screened before being loaded into the exchanger. Then, soak it in 20 solutions of 8-10% NaCl for 2-4 hours. After draining the acid, rinse the resin with water until the drainage is close to neutral. Then load the resin into the equipment to the specified height. Rinse once after resin installation.

2. Run
Maintain a certain height of water cushion layer inside the equipment to prevent water from directly impacting the pressure layer on the resin layer. Before putting into operation, it is necessary to perform a positive wash. Namely: Open the inlet valve and exhaust valve, promptly close the exhaust valve when the water is full, open the positive wash drainage valve, close the positive wash drainage valve immediately when the water quality is qualified, open the outlet valve, and switch to normal operation.

3. Regeneration
When the effluent quality is unqualified or a certain volume of soft water is produced, the ion exchanger needs to stop running and undergo regeneration. The regeneration steps are as follows:

⑴ Small backwash:Before regeneration, a small backwash should be carried out on the grease layer above the intermediate drainage pipe to wash away the dirt accumulated on the grease layer and the intermediate drainage device during operation. When performing a small backwash, first close the inlet and outlet valves, and then open the inlet and outlet valves of the small backwash. The flow rate is generally 5-10 meters per hour, and the time is 3-5 minutes. After the small backwash is completed, close the small backwash inlet valve and backwash drain valve.

⑵ Enter the regeneration solution:Open the regeneration liquid inlet valve, input the regeneration liquid from the bottom of the equipment, and then open the intermediate discharge valve. The regeneration waste liquid is discharged from the intermediate device. To ensure the regeneration effect, the regeneration flow rate should be controlled at 5 meters per hour, and the salt concentration should be controlled at 5-8%. (Replace after regeneration is complete)

⑶ Small washing:During the process of entering the regeneration solution, some waste liquid will seep into the pressure layer. In order to save water consumption and shorten the washing time, a small washing machine is used to wash this waste liquid evenly before washing. When washing, open the inlet valve and then open the middle drain valve. Water is discharged from the middle drain device at a flow rate of 10-15 meters per hour for about 5-10 minutes.

⑷ Positive washing:After the small positive washing is completed, close the middle drain valve and open the positive washing drain valve for positive washing. The flow rate should be the same as the operating flow rate. When the effluent quality meets the requirements, close the drain valve and open it for normal operation.

⑸ Great BackwashDue to the compaction and contamination of the exchange agent, which can affect normal operation, a major backwash must be carried out after several cycles of operation. The interval between major backwashs can be determined based on the inlet turbidity, outlet quality, operating pressure difference, and exchange capacity of the factory. Generally, it is carried out once every 10-20 cycles of operation. After the major backwash, the exchange layer is disrupted. In order to restore normal exchange capacity, the regeneration agent needs to be increased by 0.5-1.0 times during the first regeneration after the major backwash. When conducting a large-scale backwash, open the inlet valve of the backwash, and the valve should be gradually increased. The backwash intensity should be controlled at the centerline of the backwash mirror. Open the backwash drain valve for backwash, and the backwash time is about 10-15 minutes.