November 13, 2023     Posted by :

Pre-treatment of new resin:

Due to various reasons such as transportation and storage, it is easy to produce dehydration of new resin. With the naked eye and feel can be found. If such a situation, in order to avoid the resin and water and other regeneration fluid contact and produce burst broken, resulting in unnecessary waste, such resin must be soaked in 8% salt water for about 16 hours (soak the best often stirred), so that the resin is fully swollen, rinsed by water to no salt flavor before use. Without the above phenomenon, the resin does not need to be pre-treated.

Resin loading:

The resin loading height of the mixed-bed system is 5(6)00mm for cation resin and 10(2)00mm for anion resin. when not re-ecological (i.e., the cation resin is of sodium type and the anion resin is of chlorine type), the cation resin loading height should not be higher than the center discharge port, but it should not be lower than 5cm of the center discharge port. the anion and cation resin loading ratio is 2:1 (or 1.5:1). 001×7(732) cation exchange resin is in the lower part, 201×7(717) anion exchange resin is in the upper part. 201×7 (717) anion exchange resin is on the top.

Resin rinsing:

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.

Pass through the resin layer at a flow rate of 2m/h with a 4-5% HCl solution of about 2 times the volume of resin. After passing all, soak for 4-8 hours, drain the acid solution, and rinse with clean water until the effluent is neutral, at a flow rate of 10-20m/h.

With about 2 times the volume of resin 2-5% NaOH solution, according to the above into the HCl solution into the method and soak. Drain the alkali solution, rinse with clean water until the water is neutral, rinse flow rate as above. Acid, alkali solution if it can be repeated 2-3 times, the effect is better.

Mixing of anion and cation resin:

  1. After rinsing, open the lower inlet and upper outlet valves, start the intermediate water pump (backwash to loosen the resin layer), and close the intermediate water pump and inlet valve when the water inside the column is discharged to 100-150mm above the surface of the resin layer;

2, open a small amount of air-vacuum valve, open and control the inlet valve of the air intake (inlet pressure of 0.1-0.15Mpa), observe the upper and lower peephole in the resin rhythmic up and down the boiling mixture, so that the upper and lower resin color shades mixed with the same. Air intake time is generally 10-15 minutes;

3、After the mixing is finished, close the air inlet valve and air venting valve, and then quickly open the upper inlet valve, intermediate water pump, and the lower discharge valve (to make the resin settle down quickly and prevent the resin from re-stratifying in the process of settling down). It is also necessary to prevent the resin from being exposed to the water surface, otherwise air bubbles will be generated between the resins, thus affecting the water quality of the effluent from the mixed bed (if the mixing effect is not good, the mixing operation can be repeated).

Ion Exchange Resins

Precautions:

Running more than one year, must check the resin actual loading height, such as the resin layer is not high enough, you need to fill the resin accordingly.

Mixed bed water indicators are mainly two, one is the conductivity <0.2us/cm, the other is the silicon content of Csio2 <0.02mg/L, as qualified.

If the mixed bed cycle of water production decreased significantly, the water indicators are not stable, regeneration of acid and alkali consumption, water consumption remains high, it is necessary to regenerate or test whether the resin is contaminated and resin strength and other indicators.

Demineralized water mixed bed regeneration requirements Description:

1, reverse osmosis membrane for chemical cleaning with citric acid solution cycle cleaning

2, mixed bed of layering thoroughly, regeneration specifications, cleaning qualified, mixed evenly = water conductivity qualified.

3, if the iron poisoning resin will be red, most of the reasons are because the resin in the use of the process due to the equipment in the iron, iron in the treatment solution, resin contamination is generally high-value iron, available 5% or so of the HCI treatment, preferably cyclic, but also can be immersed, the time in the 5-8 hours, the high-value iron into low-priced iron. After treatment, the resin is then cleaned with water.

Mixed bed water resistivity ≤ 1MΩ when the mixed bed needs to be regenerated. The mixed bed of anion and cation resin regeneration operating procedures using the “two-step regeneration method” – that is, the first anion (upper) into the alkali regeneration; and then the cation resin (lower) into the hydrochloric acid regeneration.

antions and cations resin

一. Anion and Cation resin stratification

Backwashing: open the lower inlet valve, the upper discharge valve, start the intermediate pump, with RO out of the water high flow (about 3000L / h) flushing 20 minutes after the small flow (about 600L / h) flushing for about 15 minutes to make the resin loose stratification.

Resin layering is good or bad, but also with the degree of failure of the resin, the greater the degree of resin failure, the easier the layering.

If the anion and cation resin can not be layered due to mutual bonding and clustering: slowly open a small amount of clean compressed air, and then adjust the evacuation valve, so that the compressed air from the bottom of the mixed bed into the upper discharge, from the upper and lower end of the spyglass to observe the resin loosened to facilitate the layering, depending on the situation can be extended to the operating time and number of times, and then in accordance with the above backwash method of dealing with the delamination of anion and cation resin.

Layering of anion and cation resin is one of the key and important steps in regeneration operation.

二:Excluding the water in the column

Drainage of static settlement: close the middle pump and water inlet valve, open the middle drain valve, the lower drain valve, drain the resin column of water (so as not to regenerate the liquid is diluted), water flow after the end of the static 5 minutes.

三:Precautions for preparation of acid and alkali solution

When preparing acid and alkali solution, be sure to operate carefully, wear goggles, rubber gloves and masks, etc., and keep the room ventilated; if splashed on the skin, rinse with a lot of water or consult a doctor in time.

四, Anion resin into the alkali

1, with purified water to pH = 14 lye preparation;

2, adjust the lye bucket on the outlet valve, open the lye valve (up into), start the lye pump, open the exhaust valve to exclude its air, to be lye into, completely immersed in the anionic resin layer, close the exhaust valve, open the valve and control the degree of opening in the exhaust, the lye flow rate of 300-500l / h (into the lye for about 45 minutes);

3, lye into the end, in time to use RO water to flush the diluted lye barrel and into the alkali pipeline for 20 minutes, and then close the lye pump, into the alkali valve;

4, and then open the upper water inlet valve, start the middle pump, with RO water for flushing to the middle drain valve discharge, until pH = 10. And then open the lower drain valve, close the middle drain valve until the water

五. Cation resin into the acid

1, with purified water to pH = 1 acid preparation;

2, adjust the liquid outlet valve on the acid barrel, open the acid valve (under the inlet), start the acid pump, open the evacuation valve to exclude air, to be acid into the (flow rate of about)

When the acid enters (the flow rate is about 250-300l/h) and completely immerses the anode resin layer (observed by the middle-row peephole), close the emptying valve, and at the same time, open the middle-row valve and control the degree of opening;

4, in the discharge of liquid pH = 1 can be appropriate to increase the flow of acid into the cation resin does not happen to deflection as good (into the acid takes about 40 minutes);

5, after the acid into the end, in a timely manner with RO water flushing dilution of lye barrels and into the acid pipeline for 20 minutes, close the acid pump, into the acid valve; 5, and then open the upper inlet valve, the lower inlet valve, start the middle pump with RO water for flushing, testing the middle discharge valve of the outlet pH = 7-8, close the upper inlet, the lower inlet valve, by the middle row of the water exhaust.

六, Anion and Cation resin mixing

1、After the resin is cleaned and qualified, open the lower inlet and upper outlet valves, start the intermediate water pump (backwash to loosen the resin layer), and close the intermediate water pump and inlet valve when the water inside the column is discharged to 100-150mm above the surface of the resin layer;

2、Open the small amount of evacuation valve, open and control the intake valve intake (intake pressure of)

0.1-0.15Mpa), observe the upper and lower speculum resin rhythmic up and down boiling mixed, so that the upper and lower resin color shades mixed consistently. Inlet time is generally 10-15 minutes;

3、After the mixing is finished, close the air inlet valve and air venting valve, and then quickly open the upper inlet valve, intermediate water pump, and the lower discharge valve (to make the resin settle down quickly and prevent the resin from re-stratifying in the process of settling down). It is also necessary to prevent the resin from being exposed to the water surface, otherwise air bubbles will be generated between the resins, thus affecting the water quality of the water discharged from the mixed bed (if the mixing effect is not good, the mixing operation can be repeated).

七, Mixed bed flushing

After mixing, positive washing with RO water. Positive washing flow rate is generally 2000L / h, rinse about 30 minutes to discharge water in line with the purified water quality indicators for the end.

Eight, the regeneration process may appear and countermeasures

1, resin mixing, if there are bubbles between the resin, the column can be drained by the lower exhaust valve, open the exhaust valve, and then a very low flow rate (so that the resin layer does not move) to backwash the way from the lower part of the column into the water, when the liquid surface submerged in all the resin, immediately stop the water, so as to avoid the resin floats up the stratification. Then switch to positive washing and then rinse can be.

2, factors affecting the degree of resin regeneration, mainly the amount of regenerant, concentration, purity, regeneration time, regenerant flow rate, regeneration temperature, etc., should be noted in the actual operation. Mixed bed allowable working pressure ≤ 0.2MPa.

resin



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