[Hongjie Water Service] Mixed Bed Resin Operation Manual!

Pre treatment of new resin:

Due to various reasons such as transportation and storage, it is easy for the new resin to dehydrate. It can be detected with the naked eye and touch. In this case, in order to avoid the resin from coming into contact with water and other regeneration fluids and causing unnecessary waste, it is necessary to soak this type of resin in 8% salt water for about 16 hours (preferably stirring frequently during soaking), so that the resin can fully expand and be washed with clean water until there is no salt odor before use. If there is no such phenomenon, the resin does not need to undergo pre-treatment.

Resin filling:

The resin filling height of domestic mixed bed equipment is 5 (6) 00mm for cation resin and 10 (2) 00mm for anion resin. When the cation resin is of sodium type and anion resin is of chlorine type, the filling height of cation resin should not be higher than the middle outlet, but should not be 5cm lower than the middle outlet. The filling ratio of anion and cation resin is 2:1 (or 1.5:1). 001 × 7 (732) cation exchange resin at 201 × 7 (717) anion exchange resin on top.

Resin flushing:

After the resin is loaded into the exchanger, backwash the resin layer with clean water until the effluent is clear, odorless, and free of fine resin particles.

Using a 4-5% HCl solution that is approximately twice the volume of the resin, pass through the resin layer at a flow rate of 2m/h. After all are introduced, soak for 4-8 hours, drain the acid solution, and rinse with clean water until the effluent is neutral, with a flushing flow rate of 10-20 m/h.

Using a 2-5% NaOH solution that is approximately twice the volume of the resin, inject and soak it using the same method as adding HCl solution above. Drain the alkaline solution and rinse with clean water until the effluent is neutral. The flushing flow rate is the same as above. If acid and alkali solutions can be repeated 2-3 times, the effect is better.

Mixing of anion and cation resins:

After flushing, open the lower inlet and upper discharge valves, start the middle water pump (backwashing causes the resin layer to loosen), and when the accumulated water in the column is discharged to 100-150mm above the resin layer, close the middle water pump and inlet valve; 2. Open the small evacuation valve, open and control the intake volume of the intake valve (intake pressure is 0.1-0.15Mpa), observe the rhythmic boiling and mixing of resin in the upper and lower scopes, and ensure that the color of the upper and lower resins is consistent. The intake time is generally 10-15 minutes; 3. After mixing, close the inlet valve and exhaust valve, and then quickly open the upper inlet valve, middle water pump, and lower discharge valve (to allow the resin to settle quickly and prevent the resin from re layering during the settling process). At the same time, it is also necessary to prevent the resin from coming out of the water surface, otherwise bubbles will be generated between the resins, which will affect the effluent quality of the mixed bed (if the mixing effect is poor, the mixing operation can be repeated).

Precautions:

After running for more than a year, it is necessary to check the actual filling height of the resin. If the resin layer height is not enough, it is necessary to fill the resin accordingly.

There are two main indicators for mixed bed effluent, one is conductivity<0.2us/cm, and the other is silicon content Csio2<0.02mg/L, which is considered qualified.

If the water production during the mixed bed cycle significantly decreases, the effluent indicators are unstable, and the regeneration acid alkali consumption and water consumption remain high, then it is necessary to regenerate or test the indicators such as whether the resin is contaminated and the resin strength.

Description of regeneration requirements for desalinated water mixed bed:

1. Chemical cleaning of reverse osmosis membranes using citric acid solution for cyclic cleaning

2. The stratification of the mixed bed is thorough, the regeneration is standardized, the cleaning is qualified, and the mixing is uniform=the effluent conductivity is qualified. 3. If it is iron poisoning, the resin will turn red, mostly due to the presence of iron in the equipment and treatment solution during use. Resin pollution is generally high valent iron, which can be treated with around 5% HCI. It is best to cycle or soak for 5-8 hours to convert high valent iron into low valent iron. After treatment, rinse the resin with clean water.

When the water and electricity resistance of the mixed bed is ≤ 1M Ω, the mixed bed needs to be regenerated. The operating procedures for the regeneration of anion and cation resins in this mixed bed adopt the "two-step regeneration method" - that is, first introduce alkali regeneration into the anion (upper part); Regenerate the cationic resin (lower part) with hydrochloric acid.

1、 Anion and cation resin layering

Backwashing: Open the lower inlet valve and upper discharge valve, start the intermediate water pump, and rinse with RO water at a high flow rate (about 3000L/h) for 20 minutes. Then, rinse with low flow rate (about 600L/h) for about 15 minutes to loosen and layer the resin.

The quality of resin layering is also related to the degree of resin failure. The greater the degree of resin failure, the easier the layering.

If the anion and cation resins cannot be layered due to mutual adhesion and clumping: slowly open a small amount of clean compressed air, and then adjust the evacuation valve to allow the compressed air to be discharged from the mixed bed from bottom to top. Observe the resin looseness from top to bottom through a endoscope to facilitate layering. Depending on the situation, the operation time and number of times can be extended, and then handle the layering of the anion and cation resins according to the above backwashing method.

The layering of anion and cation resins is one of the crucial and important steps in the regeneration operation.

2、 Remove accumulated water inside the column)

Drainage settling: Close the middle water pump and inlet valve, open the middle and lower discharge valves, and drain the accumulated water in the resin column (to avoid dilution of the regeneration liquid). After the water flow is exhausted, let it stand for 5 minutes.

3、 Precautions for preparing acid-base solution

Be careful when preparing acid-base solutions, wear protective goggles, rubber gloves, and masks, and maintain indoor ventilation; If splashed onto the skin, rinse with plenty of water or seek medical attention promptly.

4、 Anion resin alkali injection

1. Prepare alkaline solution with pH=14 using purified water; 2. Adjust the outlet valve on the alkali solution barrel, open the inlet valve (upper inlet), start the alkali solution pump, open the exhaust valve to remove air, and when the alkali solution enters and completely immerses the anion resin layer, close the exhaust valve, open the intermediate discharge valve, and control the opening degree of the intermediate discharge. The alkali solution flow rate is 300-500l/h (about 45 minutes for alkali injection); 3. After the alkali solution is injected, rinse the diluted alkali solution bucket and alkali inlet pipeline with RO water in a timely manner for 20 minutes, and then close the alkali solution pump and alkali inlet valve; 4. Open the upper inlet valve again, start the middle water pump, and rinse with RO water until the middle discharge valve is discharged until pH=10. Open the lower drain valve again and close the middle drain valve until water flows out

5、 Acid feeding of cation resin

1. Prepare an acid solution with pH=1 using purified water; 2. Adjust the outlet valve on the acid tank, open the inlet valve (lower inlet), start the acid pump, open the vent valve to remove air, and wait for the acid to enter (with a flow rate of approximately

When fully immersing the cation resin layer (250-300l/h) (observed by the middle discharge endoscope), close the evacuation valve, and at the same time, open the middle discharge valve and control its opening degree; 3. When the pH of the discharged liquid is 1, the acid inlet flow rate can be appropriately increased to ensure that the cation resin does not deform (acid inlet takes about 40 minutes); 4. After the acid solution is injected, rinse the diluted alkali solution bucket and acid inlet pipeline with RO water in a timely manner for 20 minutes, and close the acid pump and acid inlet valve; 5. Open the upper and lower inlet valves again, start the middle water pump to flush with RO water, and when the outlet pH of the middle discharge valve is tested to be 7-8, close the upper and lower inlet valves to drain the water completely from the middle discharge.

6、 Mixing of anion and cation resins

1. After the resin cleaning is qualified, open the lower inlet and upper outlet valves, start the middle water pump (backwashing causes the resin layer to loosen), and when the accumulated water in the column is discharged to 100-150mm above the resin layer, close the middle water pump and inlet valve; 2. Open the small evacuation valve, open and control the intake volume of the intake valve (intake pressure is

0.1-0.15Mpa), observe the rhythmic boiling and mixing of resin in the upper and lower scopes, so that the color of the upper and lower resins is evenly mixed. The intake time is generally 10-15 minutes; 3. After mixing, close the inlet valve and exhaust valve, and then quickly open the upper inlet valve, middle water pump, and lower discharge valve (to allow the resin to settle quickly and prevent the resin from re layering during the settling process). At the same time, it is also necessary to prevent the resin from coming out of the water surface, otherwise bubbles will be generated between the resins, which will affect the effluent quality of the mixed bed (if the mixing effect is poor, the mixing operation can be repeated).

7、 Flushing of mixed bed

After mixing, wash with RO water. The washing flow rate is generally 2000L/h, and the washing is about 30 minutes, with the discharge water meeting the purified water quality indicators as the endpoint.

8、 Possible problems and countermeasures during the regeneration process

1. If there are bubbles between the resins after mixing, the accumulated water in the column can be discharged through the lower discharge valve, the exhaust valve can be opened, and then the water enters the lower part of the column through backwashing at a very low flow rate (to keep the resin layer stationary). When the liquid level submerges all the resins, the water inlet should be immediately stopped to prevent the resin from floating and layering. Then switch to washing method and rinse again.

2. The factors that affect the degree of resin regeneration mainly include the dosage, concentration, purity, regeneration time, flow rate of regeneration agent, and temperature during regeneration, which should be paid attention to in practical operation. The allowable working pressure of the mixed bed is ≤ 0.2MPa.

The above is the "Mixed Bed Resin Operation Manual!" introduced by Hongjie Water, hoping to be helpful to you.