A method for topless static counterflow regeneration of a desalination water production system series

Abstract

The present application belongs to the technical field of countercurrent regeneration, and particularly relates to a method for series topless static countercurrent regeneration of a desalted water preparation system. A regeneration water flow of a series countercurrent regeneration double-chamber anion exchanger of the desalted water preparation system is established; alkali is fed into the series countercurrent regeneration double-chamber anion exchanger of the desalted water preparation system; a regeneration water flow of a series countercurrent regeneration cation exchanger of the desalted water preparation system is established; acid is fed into the series countercurrent regeneration cation exchanger of the desalted water preparation system; the time for feeding acid and alkali into the series ion exchanger regeneration of the desalted water preparation system is set; the series ion exchanger resin of the desalted water preparation system is statically regenerated; the series countercurrent regeneration cation exchanger of the desalted water preparation system is replaced; the series countercurrent regeneration double-chamber anion exchanger of the desalted water preparation system is replaced; and the series ion exchanger of the desalted water preparation system is washed and qualified to be standby. The present application reduces the water intake and wastewater discharge of a power plant to the environment, and is beneficial to the protection of the environment by the power plant.

Description

Technical Field

[0001] This invention belongs to the field of countercurrent regeneration technology, specifically relating to a method for static countercurrent regeneration of a series of demineralized water preparation systems without top pressure. Background Technology

[0002] The first phase of Jiangsu Nuclear Power Co., Ltd.'s project was designed and equipped by Russia, consisting of two VVER-1000 units with a total rated power of 2×1060MW and a design life of 40 years. Each of the two units is equipped with a demineralized water preparation system.

[0003] The demineralized water preparation system provides qualified demineralized water to the unit. The water production process is as follows: pretreated water → pretreated water pump → pretreated water heater → countercurrent regeneration cation exchanger (cation bed ion exchanger) → resin trap → decarbonator → decarbonation pump → countercurrent regeneration dual-chamber anion exchanger (anion exchanger bed) → mixed ion exchanger (mixed bed ion exchanger) → resin trap → makeup water system, etc. The countercurrent regeneration cation exchanger (cation bed ion exchanger) → resin trap → decarbonator → decarbonation pump → countercurrent regeneration dual-chamber anion exchanger (anion bed ion exchanger) is called a series. Each unit's demineralized water preparation system has three series. When the conductivity of the outlet water from the countercurrent regeneration dual-chamber anion exchanger exceeds 6 μS / cm, the series fails and reaches its end point, and the series will be taken out of operation for regeneration.

[0004] Regeneration is the process by which resin, after a period of desalination operation, loses its ability to exchange ions. This loss of ion-exchange capacity can be restored using acids, alkalis, or salts. The process of restoring the resin's exchange capacity is called resin regeneration. Countercurrent regeneration occurs when the regenerant flows in the opposite direction to the water purification process within the exchanger. Figure 1 : A simplified diagram of the demineralized water preparation system's series operation and regeneration pipelines. The system's operating direction is as follows: incoming water flows from top to bottom through pipeline 1, passes through the countercurrent regeneration cation exchanger, then through pipeline 2 into the countercurrent regeneration dual-chamber anion exchanger, flows from top to bottom through the countercurrent regeneration dual-chamber anion exchanger, and then exits through pipeline 3. Regeneration is performed after series operation failure. Regenerated solution enters through the series ion exchanger effluent device, and water exits through the series ion exchanger influent device. See attached diagram. Figure 1 : Simplified diagram of the demineralized water preparation system's series operation and regeneration pipelines. The countercurrent regeneration cation exchanger receives regenerated liquid through pipeline 10 and exits through pipeline 11; the countercurrent regeneration dual-chamber anion exchanger receives regenerated liquid through pipeline 6 and exits through pipeline 7.

[0005] The volume of resin changes before and after regeneration, varying from 5% to 30% depending on the type of resin. The countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger have a diameter of 2.6m. Rubber air bladders are arranged on top of the resin to provide upward pressure and fill the space for resin transformation, preventing resin layer disorder during countercurrent regeneration. The countercurrent regeneration cation exchanger has a resin loading capacity of 13m³. 3 The design includes 54 airbags in two layers; the lower chamber of the countercurrent regeneration dual-chamber anion exchanger has a strong anion resin loading capacity of 4m³. 3 The design includes 27 airbags in one layer, with a 9m³ capacity of weak anion resin in the upper chamber. 3 The design incorporates 81 airbags in 3 layers. The two units are equipped with a total of 972 airbags for the top pressure device. The unit price of each airbag is 4,289 yuan, totaling 20.845 million yuan.

[0006] Problems encountered on-site: As the system operates, the airbags float within the ion exchanger, resulting in uneven distribution, especially in the weak anion resin chamber. In some areas, there are 4-5 layers, while in others, only 1-2 layers. During resin regeneration, this leads to disordered resin layering, poor regeneration efficiency, requiring 2-3 regeneration cycles to produce water, and the regeneration effect is unstable, with significant fluctuations in water production per cycle. When new airbags are installed in the system, inspections after approximately 3 months reveal numerous damaged airbags. Due to airbag compression damage, regenerant enters the airbags during regeneration, causing substandard long-term flushing performance. Furthermore, damaged airbags submerged in the resin layer result in uneven water distribution during ion exchanger production and regeneration, creating dead zones where resin cannot be regenerated, impacting operation. High airbag consumption increases production costs.

[0007] In summary, the countercurrent regeneration process of the series is unstable, the series operation is unstable, and 2-3 regenerations are required for normal operation. The cycle water production also decreases by more than 30%, the wastewater volume increases, and the production cost increases.

[0008] In the series of countercurrent regeneration processes of demineralized water preparation systems at home and abroad, top pressure facilities, equipment, and packing materials need to be installed at the top of the ion exchanger, or a regeneration liquid drain pipe needs to be added to the side of the ion exchanger, and a regeneration drainage device needs to be installed on the top of the resin. Before regeneration, water needs to be drained to the location of this device. After the ion exchanger has been running for a certain period of time, the packing materials also need to be backwashed to ensure the normal operation of the system. Summary of the Invention

[0009] The purpose of this invention is to provide a method for static countercurrent regeneration of a series of demineralized water preparation systems without top pressure. No top pressure facilities or equipment are required at the top of the countercurrent regeneration ion exchanger, no packing is required, and there is no need to set up a regeneration drainage device on the top of the resin or add a drainage pipe on the side of the filter, while ensuring the safe and stable operation of the system.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for static countercurrent regeneration of a series of demineralized water preparation systems without top pressure is disclosed, comprising: setting up a pressure-free system; filling the ion exchangers with water; establishing a regeneration water flow for the countercurrent regeneration of the dual-chamber anion exchangers in the demineralized water preparation system; introducing alkali into the dual-chamber anion exchangers in the countercurrent regeneration of the demineralized water preparation system; establishing a regeneration water flow for the cation exchangers in the countercurrent regeneration of the demineralized water preparation system; introducing acid into the cation exchangers in the countercurrent regeneration of the demineralized water preparation system; setting the acid and alkali induction times for the regeneration of the ion exchangers in the demineralized water preparation system; static regeneration of the resin in the ion exchangers in the demineralized water preparation system; purging the cation exchangers in the countercurrent regeneration of the demineralized water preparation system; purging the dual-chamber anion exchangers in the countercurrent regeneration of the demineralized water preparation system; and rinsing the ion exchangers in the demineralized water preparation system until they are qualified and ready for use.

[0012] Setting up pressure-free operation: Unload the original air bladders in the ion exchangers of the demineralized water preparation system series; remove the original pressure-reducing facilities in the ion exchangers of the demineralized water preparation system series, that is, unload the air bladders from the countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger. There are no pressure-reducing facilities or equipment on the upper layer of the resin, and no additional inlet or outlet pipes are needed; Fill the ion exchangers with water: Fill the ion exchangers of the demineralized water preparation system series with water; regeneration operation requires the ion exchangers to be in a full water state.

[0013] Establish the regeneration water flow of the series countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system: Start the demineralized water pump to establish the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger, with the flow rate set at 2.5 kg / s. The water flows into the countercurrent regeneration dual-chamber anion exchanger through pipes 4 and 6 and flows out from pipe 7.

[0014] Introduce alkali into the series of countercurrent regeneration dual-chamber anion exchangers in the demineralized water preparation system: After the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger is established for 3 minutes, start the alkali pump to input the regeneration alkali solution with a concentration of 3.5% into the countercurrent regeneration dual-chamber anion exchanger through pipeline 5.

[0015] Establish the regeneration water flow of the series countercurrent regeneration cation exchangers in the demineralized water preparation system: After the regeneration water flow of the series countercurrent regeneration dual-chamber anion exchangers in the demineralized water preparation system is established for 1 hour, start the demineralized water pump to establish the regeneration water flow of the countercurrent regeneration cation exchangers. The flow rate is set to 3.5 kg / s. The water flows into the countercurrent regeneration cation exchangers through pipes 8 and 10 and flows out from pipe 11.

[0016] Acid is introduced into the series of countercurrent regenerated cation exchangers of the demineralized water preparation system: After the regenerated water flow of the countercurrent regenerated cation exchanger is established for 3 minutes, the acid pump is started to input the regenerated acid solution with a concentration of 3.5% into the countercurrent regenerated cation exchanger.

[0017] The regeneration acid and alkali inlet times for the series ion exchangers in the demineralized water preparation system are set as follows: alkali inlet time for the countercurrent regeneration dual-chamber anion exchanger is 3 hours, and acid inlet time for the countercurrent regeneration cation exchanger is 2 hours. The acid and alkali inlet operations are stopped simultaneously, i.e., the alkali inlet pump and demineralized water pump of the countercurrent regeneration dual-chamber anion exchanger and the acid inlet pump and demineralized water pump of the countercurrent regeneration cation exchanger are stopped. Static regeneration of the resin in the series ion exchangers of the demineralized water preparation system: static regeneration of the resin in the countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger is performed for 4 hours.

[0018] Demineralized water preparation system series countercurrent regeneration cation exchanger replacement: Start the demineralized water pump to establish the regeneration water flow of the countercurrent regeneration cation exchanger. The water flows into the countercurrent regeneration cation exchanger through pipes 8 and 10 and flows out from pipe 11. The flow rate is set to 3.5 kg / s and the time is 3 hours.

[0019] Replacement of the countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system: Simultaneously with the replacement of the countercurrent regeneration cation exchanger in the demineralized water preparation system, the demineralized water pump is started to establish the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger. The water flows into the countercurrent regeneration dual-chamber anion exchanger through pipes 4 and 6 and flows out through pipe 7. The flow rate is set to 2.5 kg / s and the time is 3 hours.

[0020] After the series of ion exchangers in the demineralized water preparation system have passed the flushing test and are ready for standby: After the countercurrent regeneration cation exchanger replacement and the countercurrent regeneration dual-chamber anion exchanger replacement are simultaneously stopped, the water production process is started, and the countercurrent regeneration cation exchanger is flushed at a flow rate of 26 kg / s for 10 min. Then, the countercurrent regeneration dual-chamber anion exchanger is connected at a flow rate of 26 kg / s for combined flushing until the conductivity of the countercurrent regeneration dual-chamber anion exchanger is less than 6 micro Siemens / cm for 1 hour and 10 min. The series of ion exchangers in the demineralized water preparation system are then ready for standby.

[0021] The beneficial effects achieved by this invention are as follows:

[0022] This method has been verified in the field and its effects are significant. It eliminates the original pressure-generating device, increasing the system's cycle water production to approximately twice the original amount without changing the resin loading or increasing the regeneration reagent dosage, while maintaining stable system operation. The method also eliminates the rubber air bladder of the original pressure-generating device, saving on procurement costs. Furthermore, it requires no new operations from operators, the regeneration sequence is easy to master, and it is easy to implement on-site. The increased cycle water production reduces the workload of operators. Compared to the original method, using this method for a single regeneration saves on the amount of demineralized water used. It also reduces the pressure on the power plant's water supply, which is beneficial for the utilization of the power plant's water resources. Finally, it reduces the power plant's water intake and wastewater discharge, contributing to environmental protection. Attached Figure Description

[0023] Figure 1 A simplified diagram of the regeneration pipeline system for the demineralized water preparation system. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] (1) Setting conditions

[0026] ① Set to no top pressure;

[0027] ② Fill the ion exchanger with water:

[0028] (2) Regeneration steps

[0029] ①Establish a series of countercurrent regeneration dual-chamber anion exchangers for the demineralized water preparation system;

[0030] ②Introduce alkali into the series of countercurrent regeneration dual-chamber anion exchangers in the demineralized water preparation system;

[0031] ③ Establish a series of countercurrent regeneration cation exchangers in the demineralized water preparation system to generate regenerated water flow;

[0032] ④ Introduce acid into the series of countercurrent regeneration cation exchangers of the demineralized water preparation system;

[0033] ⑤ Set the regeneration acid and alkali inlet times for the series ion exchangers in the demineralized water preparation system;

[0034] ⑥ Static regeneration of the resin in the series of ion exchangers of the demineralized water preparation system;

[0035] ⑦ The demineralized water preparation system uses a series of countercurrent regeneration cation exchangers for replacement.

[0036] ⑧ The demineralized water preparation system uses a series of countercurrent regeneration dual-chamber anion exchangers for replacement;

[0037] ⑨ The series of ion exchangers in the demineralized water preparation system are flushed and ready for use.

[0038] Setting up pressure-free: Unload the original airbags in the series of ion exchangers of the demineralized water preparation system; unload the original pressure-reducing facilities in the series of ion exchangers of the demineralized water preparation system, that is, unload the airbags from the countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger. There are no pressure-reducing facilities or equipment on the upper layer of the resin, and there is no need to add inlet and outlet pipes.

[0039] Filling the ion exchangers with water: Fill the series of ion exchangers in the demineralized water preparation system with water; regeneration operation requires the ion exchangers to be in a full water state. Start the demineralized water system and fill the series of ion exchangers in the demineralized water preparation system with water before regeneration until they are full.

[0040] 1. Establish a series of countercurrent regeneration dual-chamber anion exchangers for the demineralized water preparation system;

[0041] Start the demineralized water pump to establish a counter-current regeneration flow for the dual-chamber anion exchanger. Set the flow rate to 2.5 kg / s. (See attached diagram) Figure 1 : A simplified diagram of the demineralized water preparation system's series of operation and regeneration pipelines. Water flows through pipelines 4 and 6 into the countercurrent regeneration dual-chamber anion exchanger and flows out from pipeline 7.

[0042] 2. Introduce alkali into the series of countercurrent regeneration dual-chamber anion exchangers in the demineralized water preparation system;

[0043] After the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger is established for 3 minutes, the alkali pump is started to input the regeneration alkali solution with a concentration of 3.5% into the countercurrent regeneration dual-chamber anion exchanger through pipeline 5.

[0044] 3. Establish a series of countercurrent regeneration cation exchangers in the demineralized water preparation system to generate regenerated water flow;

[0045] After step 1 has been executed for 1 hour, start the demineralized water pump to establish a countercurrent regeneration flow for the cation exchanger. The flow rate is set to 3.5 kg / s. (See attached diagram) Figure 1 : A simplified diagram of the demineralized water preparation system's series of operation and regeneration pipelines. Water flows through pipelines 8 and 10 into the countercurrent regeneration cation exchanger and flows out from pipeline 11.

[0046] 4. Introduce acid into the series of countercurrent regenerated cation exchangers of the demineralized water preparation system;

[0047] After the regenerated water flow in the countercurrent cation exchanger has been established for 3 minutes, start the acid pump to input regenerated acid solution with a concentration of 3.5% into the countercurrent cation exchanger.

[0048] 5. Set the regeneration acid and alkali inlet times for the series ion exchangers in the demineralized water preparation system;

[0049] The countercurrent regeneration dual-chamber anion exchanger is fed with alkali for 3 hours and the countercurrent regeneration cation exchanger is fed with acid for 2 hours. The acid and alkali feeding operations are stopped simultaneously, that is, the alkali feed pump and demineralized water pump of the countercurrent regeneration dual-chamber anion exchanger and the acid feed pump and demineralized water pump of the countercurrent regeneration cation exchanger are stopped.

[0050] 6. Static regeneration of resin in a series of ion exchangers for demineralized water preparation systems;

[0051] Static regeneration was performed on the resin in the countercurrent regenerated cation exchanger and the resin in the countercurrent regenerated dual-chamber anion exchanger for 4 hours.

[0052] 7. Demineralized water preparation system with series countercurrent regeneration cation exchanger replacement;

[0053] Start the demineralized water pump to establish a counter-current regeneration flow for the cation exchanger, see attached. Figure 1 : Simplified diagram of the demineralized water preparation system's series operation and regeneration pipelines. Water flows through pipelines 8 and 10 into the countercurrent regeneration cation exchanger and exits from pipeline 11. The flow rate is set at 3.5 kg / s, and the time is 3 hours.

[0054] 8. Demineralized water preparation system with series countercurrent regeneration dual-chamber anion exchange replacement;

[0055] Simultaneously with step 7, start the demineralized water pump to establish a counter-current regeneration flow for the dual-chamber anion exchanger, as shown in the appendix. Figure 1 : Simplified diagram of the demineralized water preparation system's series operation and regeneration pipelines. Water flows through pipes 4 and 6 into the countercurrent regeneration dual-chamber anion exchanger and exits from pipe 7. The flow rate is set at 2.5 kg / s, and the time is 3 hours.

[0056] 9. The series of ion exchangers in the demineralized water preparation system are flushed and ready for use.

[0057] After the countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger are simultaneously stopped, the water production process is started. The countercurrent regeneration cation exchanger is flushed at a flow rate of 26 kg / s for 10 minutes. Then, the countercurrent regeneration dual-chamber anion exchanger is connected at a flow rate of 26 kg / s for a combined flush. The flushing continues until the conductivity of the countercurrent regeneration dual-chamber anion exchanger is less than 6 micro Siemens / cm, which takes about 1 hour and 10 minutes. The series of ion exchangers in the demineralized water preparation system are then flushed and ready for use.

Claims

1. A method for series-stage static countercurrent regeneration of a demineralized water preparation system without top pressure, characterized in that: Set no top pressure; fill the ion exchanger with water: establish the regeneration water flow of the series countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system; introduce alkali into the series countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system; establish the regeneration water flow of the series countercurrent regeneration cation exchanger in the demineralized water preparation system; introduce acid into the series countercurrent regeneration cation exchanger in the demineralized water preparation system; set the acid and alkali introduction time for the regeneration of the series ion exchangers in the demineralized water preparation system; static regeneration of the resin in the series ion exchangers in the demineralized water preparation system; replacement of the series countercurrent regeneration cation exchanger in the demineralized water preparation system; replacement of the series countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system; rinse the series ion exchangers in the demineralized water preparation system until qualified and ready for use.

2. The method for series static countercurrent regeneration of demineralized water preparation system without top pressure according to claim 1, characterized in that: Setting up pressure-free operation: Unload the original air bladders in the ion exchangers of the demineralized water preparation system series; remove the original pressure-reducing facilities in the ion exchangers of the demineralized water preparation system series, that is, unload the air bladders from the countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger. There are no pressure-reducing facilities or equipment on the upper layer of the resin, and no additional inlet or outlet pipes are needed; Fill the ion exchangers with water: Fill the ion exchangers of the demineralized water preparation system series with water; regeneration operation requires the ion exchangers to be in a full water state.

3. The method for series static countercurrent regeneration of demineralized water preparation system without top pressure according to claim 2, characterized in that: Establish the regeneration water flow of the series countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system: Start the demineralized water pump to establish the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger, with the flow rate set at 2.5 kg / s. The water flows into the countercurrent regeneration dual-chamber anion exchanger through pipes 4 and 6 and flows out from pipe 7.

4. The method for series static countercurrent regeneration of demineralized water preparation system without top pressure according to claim 3, characterized in that: Introduce alkali into the series of countercurrent regeneration dual-chamber anion exchangers in the demineralized water preparation system: After the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger is established for 3 minutes, start the alkali pump to input the regeneration alkali solution with a concentration of 3.5% into the countercurrent regeneration dual-chamber anion exchanger through pipeline 5.

5. The method for series top-pressure-free static countercurrent regeneration of the demineralized water preparation system according to claim 4, characterized in that: Establish the regeneration water flow of the series countercurrent regeneration cation exchangers in the demineralized water preparation system: After the regeneration water flow of the series countercurrent regeneration dual-chamber anion exchangers in the demineralized water preparation system is established for 1 hour, start the demineralized water pump to establish the regeneration water flow of the countercurrent regeneration cation exchangers. The flow rate is set to 3.5 kg / s. The water flows into the countercurrent regeneration cation exchangers through pipes 8 and 10 and flows out from pipe 11.

6. The method for series top-pressure-free static countercurrent regeneration of the demineralized water preparation system according to claim 5, characterized in that: Acid is introduced into the series of countercurrent regenerated cation exchangers of the demineralized water preparation system: After the regenerated water flow of the countercurrent regenerated cation exchanger is established for 3 minutes, the acid pump is started to input the regenerated acid solution with a concentration of 3.5% into the countercurrent regenerated cation exchanger.

7. The method for series top-pressure-free static countercurrent regeneration of the demineralized water preparation system according to claim 6, characterized in that: The regeneration acid and alkali inlet times for the series ion exchangers in the demineralized water preparation system are set as follows: alkali inlet time for the countercurrent regeneration dual-chamber anion exchanger is 3 hours, and acid inlet time for the countercurrent regeneration cation exchanger is 2 hours. The acid and alkali inlet operations are stopped simultaneously, i.e., the alkali inlet pump and demineralized water pump of the countercurrent regeneration dual-chamber anion exchanger and the acid inlet pump and demineralized water pump of the countercurrent regeneration cation exchanger are stopped. Static regeneration of the resin in the series ion exchangers of the demineralized water preparation system: static regeneration of the resin in the countercurrent regeneration cation exchanger and the countercurrent regeneration dual-chamber anion exchanger is performed for 4 hours.

8. The method for series static countercurrent regeneration of demineralized water preparation system without top pressure according to claim 7, characterized in that: Demineralized water preparation system series countercurrent regeneration cation exchanger replacement: Start the demineralized water pump to establish the regeneration water flow of the countercurrent regeneration cation exchanger. The water flows into the countercurrent regeneration cation exchanger through pipes 8 and 10 and flows out from pipe 11. The flow rate is set to 3.5 kg / s and the time is 3 hours.

9. The method for series top-pressure-free static countercurrent regeneration of the demineralized water preparation system according to claim 8, characterized in that: Replacement of the countercurrent regeneration dual-chamber anion exchanger in the demineralized water preparation system: Simultaneously with the replacement of the countercurrent regeneration cation exchanger in the demineralized water preparation system, the demineralized water pump is started to establish the regeneration water flow of the countercurrent regeneration dual-chamber anion exchanger. The water flows into the countercurrent regeneration dual-chamber anion exchanger through pipes 4 and 6 and flows out through pipe 7. The flow rate is set to 2.5 kg / s and the time is 3 hours.

10. The method for series top-pressure-free static countercurrent regeneration of the demineralized water preparation system according to claim 9, characterized in that: After the series of ion exchangers in the demineralized water preparation system have passed the flushing test and are ready for standby: After the countercurrent regeneration cation exchanger replacement and the countercurrent regeneration dual-chamber anion exchanger replacement are simultaneously stopped, the water production process is started, and the countercurrent regeneration cation exchanger is flushed at a flow rate of 26 kg / s for 10 min. Then, the countercurrent regeneration dual-chamber anion exchanger is connected at a flow rate of 26 kg / s for combined flushing until the conductivity of the countercurrent regeneration dual-chamber anion exchanger is less than 6 micro Siemens / cm for 1 hour and 10 min. The series of ion exchangers in the demineralized water preparation system are then ready for standby.

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