Mixed bed regeneration, with how much acid and alkali equipped? How to match the regeneration proces

Generally, before the regeneration of the mixed bed, it is necessary to backwash the resin bed with a certain flow of water to replace the anion and ion.

Separation, this step is very crucial, only when the separation is good, can the next step of regeneration! Generally, the test is used to grasp the size of the flow rate. After separation, there is a regeneration tube in the middle of the mixed bed, which is passed into the diluted to 5% HCl solution to regenerate the positive resin.

Generally, the regeneration rate (i.e., the flow rate of the dilute solution of hydrochloric acid) should also be controlled, and the regeneration cation will end in about half an hour; Wash with pure water for about 15 minutes. Then introduce a diluted 5% NaOH solution to regenerate the anion resin, and generally control the regeneration rate (i.e., dilute sodium hydroxide.

flow rate of the solution), about one hour (anion.

Slow regeneration reaction! ), the end of anion regeneration; Wash with pure water for about 30 minutes. (Note that the drainage direction of anion and cation regeneration is reversed, one is upward and the other is downward, as long as the resin to be regenerated is passed).

Then use clean compressed air (to remove oil!) Stir the resin, mix the yin and yang resin thoroughly, wash it with pure water, and compact the resin from top to bottom, and then you can make water again!

It can be calculated according to the amount of positive resin exchange per mol 100 150 grams of HCI pure products, and the amount of anion resin exchange per mol 200 250 grams of pure NaOH products can be calculated The concentration can be controlled at 5% 10%, and the time can be controlled at 30 40min.

Generally, the concentration of acid and alkali regeneration solution of mixed bed resin is: 3-6%.

If the concentration of the regeneration solution is too high, it will cause pressure to the later water washing, especially the negative resin alkali washing will waste a lot of pure water.

Open the inlet door of the mixed-bed regeneration pump, start the regeneration pump, and then open the outlet door of the mixed-bed regeneration pump, the mixed-bed backwash drainage door and the exhaust air door, and backwash the inlet door. When water flows out of the drain door, close the vent door. The flow rate should be small at the beginning, and after the resin is loosened, gradually increase the flow rate until all the beds can be loosened, and the flow rate will reach about 10m h.

The expansion rate of anion resin is more than 70%, and the expansion rate of positive resin is about 30% or more, so that the yin and yang resin can be layered after 10-15 minutes.

How much alkali is used for regeneration at one time? How much acid is better.

Summary. Hello dear<>

The use of acid for stratification in mixed bed regeneration can improve the life of mixed beds. A mixed bed is made by mixing anion-exchange resins and cation-exchange resins together in a certain proportion. Anion exchange resins are mainly used to remove cations from water when mixed bed treatment water, and cation exchange resins are mainly used to remove anions from water.

When the mixed bed is used for a period of time, both the cation exchange resin and the anion exchange resin will be occupied by ions in the water, resulting in a decrease in the mixed bed treatment effect.

Is it possible to improve the life of the mixed bed by acid stratification before the regeneration of the mixed bed.

Never mind. Hello dear<>

The use of acid for stratification in mixed bed regeneration can improve the life of mixed beds. A mixed bed is made by mixing anion-exchange resins and cation-exchange resins together in a certain proportion. Anion exchange resins are mainly used to remove cations from water when mixed bed treatment water, and cation exchange resins are mainly used to remove anions from water.

When the mixed bed is used for a period of time, both the cation exchange resin and the anion exchange resin will be occupied by ions in the water, resulting in a decrease in the mixed bed treatment effect.

By layering the mixed bed with acid, some different types of ions can be removed, so that the exchange efficiency of the mixed bed for ions in water is improved, and the service life of the mixed bed can be prolonged.

In other words, the resistance can also be increased quickly.

Hello dear<>

The increase in electrical resistance is less correlated with acid stratification in mixed-bed regeneration. Resistance water treatment is a commonly used deionization method to remove ions from water by separating cations and anions in water by means of electrolysis. In resistive water treatment, ion exchange membranes are used instead of exchange resins.

Therefore, the principle of resistance water treatment is different from that of mixed bed treatment, and the methods of improving efficiency are also different. However, some strategies can improve the efficiency of resistive deionization equipment by increasing the number of backwashes and changing the backwash method.

Thank you for answering the questions in my mind.

The main operation steps are:

1) Backwash before mixed bed regeneration, with a flow rate of 10m h, and a backwash control time of 10-15 minutes;

2) Wait for the resin layer to be stratified;

3) Discharge water to a water level of about 10cm above the resin layer in the exchanger;

4) Alkali is fed from the upper alkali inlet pipe, the flow rate is 4m h, the alkali concentration is 4%, and the alkali inlet time is more than 15 minutes; At the same time, water is fed through the acid inlet pipe at the lower part of the exchanger, and the water flows through the cation resin.

After the layer, it is discharged together with the waste lye by the middle drain pipe at the interface of the yang and anion resin layers;

5) Replace the anion resin according to the same process, the flow rate is 4m h, and the time is greater than 15 minutes;

6) The negative resin is washed, the flow rate is 15m h, the amount of washing water is controlled by 10m3 water and 1 m3 resin, and the alkalinity of phenolphthalein is lower than the following;

7) Acid regeneration cation resin is fed into the acid inlet pipe from the lower part of the pipe, the flow rate is 4m h, the acid concentration is 5%, and the acid inlet time is greater than 15 minutes; At the same time, the upper alkali inlet pipe should be kept to continue to feed water; After the water flows through the anion resin layer, it is discharged together with the waste acid solution through the drain pipe at the interface of the yang and anion resin layers.

8) Replace and clean the cation resin according to the same process, the flow rate is 4m h, and the time is greater than 15 minutes;

9) The cation resin is cleaned, the flow rate is 10m h, and the drainage is drained by the middle drain pipe until the acidity of the drainage is lower than the following;

10) The exchanger resin is washed as a whole, water is fed from the top of the exchanger, and the water is drained by the exchanger's washing drainage valve, with a flow rate of 15m h, and the conductivity of the water is washed to the drainage.

below the following; 11) Discharge water to the water level of the exchanger about 10cm on the resin layer;

12) Compressed air is introduced for resin mixing, compressed air pressure 1-gauge pressure, time 1-5 minutes; After the resin is mixed, it is necessary to have a high enough drainage rate to force the resin to land quickly and avoid resin re-separation. When the resin descends, the top water inlet is used to accelerate its sedimentation;

13) The mixed resin layer is washed, the flow rate is 10-20m h, and the water can be put into operation after washing until the drainage is qualified;