A transformation test method and system for a continuous electrodeionization membrane module

Abstract

The present invention discloses a transformation test method and system for a continuous electrodeionization membrane module. Tap water is filtered, dechlorinated, and pre-desalted through a raw water quality pretreatment unit, and then mixed with the fresh water generated by the continuous electrodeionization membrane module. The mixed water is filtered again and then undergoes electrolytic dissociation in the continuous electrodeionization membrane module. The dissociated hydrogen ions and hydroxide ions are used to transform and regenerate the ion exchange resin. The sodium-type cation exchange resin is converted into the hydrogen type, and the chloride-type anion exchange resin is converted into the hydroxide type. The fresh water generated by the continuous electrodeionization membrane module is returned to the mixing tank. Due to the adoption of water production reflux in the present invention, continuous circulation and sufficient mixing with the test influent in the mixing tank can improve the influent water quality of the continuous electrodeionization test, facilitate the regeneration of the sodium-type cations and chloride-type anions filled inside the continuous electrodeionization product, shorten the time for continuous electrodeionization transformation, and can save 71% of the water required for the test.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and particularly relates to a transformation test method and system for a continuous electrodeionization membrane block. Background Art

[0002] In the field of desalted water and pure water production, due to many advantages such as the continuous electrodeionization device not requiring industrial acid-base regeneration and the reliable quality of the product water, the application of this device is becoming more and more popular, gradually phasing out the traditional cation and anion exchange equipment. Currently, in the domestic market, more than 90% of the products are imported products, and domestic products are still in their infancy. Whether it is imported equipment or domestic equipment, there is no unified transformation test method and corresponding system. The performance of the equipment is tested by actual operation. When the equipment leaves the factory, only routine items such as the transformation of ion exchange resin and leakage test are carried out, and there is no fixed test method and specific parameters for the performance of the equipment.

[0003] When assembling the continuous electrodeionization membrane block, the sodium-type cation exchange resin and chloride-type anion exchange resin used need to be transformed into hydrogen-type and hydroxyl-type ion exchange resins first before testing the performance. When testing the products in the market and during transformation, tap water is purchased as the raw water, and the desalted water after reverse osmosis pretreatment is used as the inlet water for continuous electrodeionization. According to the normal process flow, the transformation test time takes 10 - 12 hours. Calculated according to the standard output of 5m 3 / h of the general-purpose continuous electrodeionization, the tap water to be consumed is 74m 3 ~89m 3 . Calculated at the price of industrial tap water of 6 yuan / m 3 , the tap water cost for each transformation test of one continuous electrodeionization membrane block is more than 400 yuan, causing great economic pressure on industrial production and wasting water resources at the same time. In addition, during transformation, the DC voltage required is about 300V and the DC current is about 3.0A. If it operates continuously for 10 - 12h, the power consumption is 10kW·h - 12kW·h. Calculated at the industrial electricity price of 5.0 yuan / kW·h, the electricity cost for each transformation test of one continuous electrodeionization membrane block is more than 50 - 60 yuan, which is also a relatively large energy consumption and uneconomical.

[0004] In summary, it is necessary to optimize the transformation test of the existing continuous electrodeionization membrane block to shorten the transformation test time in order to save industrial production time and costs. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a transformation test method and system for a continuous electrodeionization membrane block. The system has a simple process and can complete the transformation test of the continuous electrodeionization membrane block in a relatively short time.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A transformation test system for a continuous electrodeionization membrane module, comprising a raw water quality pretreatment unit and a transformation test unit. The transformation test unit includes a hybrid water tank and a continuous electrodeionization membrane module. The raw water quality pretreatment unit is connected to the inlet of the hybrid water tank. The outlet of the hybrid water tank is connected to the inlet of the continuous electrodeionization membrane module, and the outlet of the continuous electrodeionization membrane module is connected to the inlet of the hybrid water tank.

[0008] Further, the raw water quality pretreatment unit includes a connected particle filter, an ultraviolet residual chlorine decomposer, a reverse osmosis feed pump, and a reverse osmosis device, and the reverse osmosis device is connected to the hybrid water tank.

[0009] Further, the outlet of the hybrid water tank is connected to the inlet of the continuous electrodeionization membrane module through a membrane module feed pump, a membrane module precision filter, and a membrane module inlet resistivity meter.

[0010] Further, a fresh water inlet, a concentrated water inlet, and an electrode water inlet are provided on the continuous electrodeionization membrane module. The outlet of the membrane module inlet resistivity meter is divided into three paths. One path is connected to the fresh water inlet of the continuous electrodeionization membrane module through a fresh water inlet regulating valve and a fresh water inlet mass flow meter. One path is connected to the concentrated water inlet of the continuous electrodeionization membrane module through a concentrated water inlet regulating valve and a concentrated water inlet mass flow meter. One path is connected to the electrode water inlet of the continuous electrodeionization membrane module through an electrode water inlet regulating valve and an electrode water inlet mass flow meter.

[0011] Further, a product water outlet, a concentrated water outlet, and an electrode water outlet are provided on the continuous electrodeionization membrane module. The product water outlet is connected to the inlet of a membrane module product water resistivity meter. The outlet of the membrane module product water resistivity meter is divided into two paths. One path is connected to the inlet of the hybrid water tank through a membrane module product water return mass flow meter and a membrane module product water return regulating valve. The other path is discharged after passing through a membrane module product water discharge mass flow meter and a membrane module product water discharge regulating valve. Valves are provided at both the concentrated water outlet and the electrode water outlet.

[0012] Further, a membrane module DC power supply control unit is provided on the top of the continuous electrodeionization membrane module, and a fresh water inlet flow meter, a concentrated water inlet flow meter, and an electrode water inlet flow meter are connected to the membrane module DC power supply control unit.

[0013] Further, an overflow partition for dividing the internal cavity of the hybrid water tank into a mixing zone and a water absorption zone is provided in the hybrid water tank. The height of the overflow partition is two-thirds of the height of the hybrid water tank, and a swirl preventer is provided in the water absorption zone.

[0014] A transformation test method for a continuous electrodeionization membrane module based on the above system, comprising the following steps:

[0015] Tap water enters the hybrid water tank after being filtered, dechlorinated, and pre-desalted by the inlet water quality pretreatment unit. It is mixed with the fresh water produced by the continuous electrodeionization (EDI) membrane module in the hybrid water tank. The mixed water is filtered again and then undergoes electrolytic dissociation in the EDI membrane module. The dissociated hydrogen ions and hydroxide ions are used to regenerate the ion exchange resin, converting the sodium-type cation exchange resin to the hydrogen type and the chloride-type anion exchange resin to the hydroxide type. The fresh water produced by the EDI membrane module returns to the hybrid water tank.

[0016] Furthermore, the residual chlorine after dechlorination is less than 0.1 mg / L, and the conductivity of the mixed water is less than or equal to 20 μS / cm.

[0017] Furthermore, within 6 hours, the resistance of the water produced by the EDI membrane module reaches above 15 MΩ·cm.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] In the present invention, the outlet of the EDI membrane module is connected to the inlet of the hybrid water tank, and the regeneration is carried out by the method of returning the EDI product water. A small amount of product water is discharged, while in the traditional test method, all the product water is directly discharged. After comparison, the present invention can save 71% of the water required for testing, which has important economic benefits. Due to the adoption of water production reflux, continuous circulation and sufficient mixing with the test inlet water in the hybrid water tank, the inlet water quality of the EDI test can be improved. Since the salt content in the inlet water is less, under the action of the DC voltage, water molecules are more likely to dissociate in the cavity of the EDI module. The dissociated hydrogen ions and hydroxide ions have a higher concentration in the concentrated water, which is beneficial to the regeneration of the sodium-type cations and chloride-type anions filled inside the EDI product, and can shorten the transformation time of the EDI.

[0020] In the present invention, tap water enters the hybrid water tank after being filtered, dechlorinated, and pre-desalted by the pretreatment unit. It is mixed with the fresh water produced by the EDI membrane module in the hybrid water tank. The mixed water is filtered again and then undergoes electrolytic dissociation inside the EDI membrane module. The dissociated hydrogen ions and hydroxide ions are used to regenerate the ion exchange resin, converting the sodium-type cation exchange resin to the hydrogen type and the chloride-type anion exchange resin to the hydroxide type. The fresh water produced by the EDI membrane module circulates back to the hybrid water tank. The present invention puts forward the requirements for the inlet water quality and the product water quality during the regeneration of the EDI module. Each product undergoes a transformation test under the same benchmark working condition of 90% recovery rate. At the same time, the test time is proposed. Continuous testing is carried out within 6 hours without interruption, and the water production resistance of the EDI is not less than 15 MΩ·cm, which is regarded as a qualified product, meeting the performance requirements of the EDI product for industrial production and providing guarantee for the industrial preparation of pure water and ultrapure water. Description of the Drawings

[0021] Figure 1 This is a schematic structural diagram of a transformation test system for a continuous electrodeionization membrane module of the present invention.

[0022] Figure 2 This is the mass flow balance diagram of the present invention;

[0023] Figure 3 This is a conventional transformation test scheme.

[0024] Figure 1 In [the figure], 1 - particle filter, 2 - ultraviolet residual chlorine disconnector, 3 - reverse osmosis feed water pump, 4 - reverse osmosis device, 5 - hybrid water tank, 6 - membrane module feed water pump, 7 - membrane module precision filter, 8 - continuous electrodeionization membrane module, 9 - fresh water inlet regulating valve, 10 - concentrated water inlet regulating valve, 11 - electrode water inlet regulating valve, 12 - fresh water inlet mass flowmeter, 13 - concentrated water inlet mass flowmeter, 14 - electrode water inlet mass flowmeter, 15 - membrane module inlet conductivity meter, 16 - membrane module product water conductivity meter, 17 - membrane module product water discharge mass flowmeter, 18 - membrane module product water discharge regulating valve, 19 - membrane module product water reflux mass flowmeter, 20 - membrane module product water reflux regulating valve, 21 - membrane module DC power supply control unit. Specific embodiments

[0025] The present invention will be further described in detail below with reference to the accompanying drawings.

[0026] See Figure 1 , a transformation test system for a continuous electrodeionization membrane module according to the present invention mainly includes a pretreatment unit and a transformation test unit. The pretreatment unit includes a particle filter 1, an ultraviolet residual chlorine disconnector 2, a reverse osmosis feed water pump 3, and a reverse osmosis device 4. The transformation test unit includes a hybrid water tank 5, a membrane module feed water pump 6, a membrane module precision filter 7, a continuous electrodeionization membrane module 8, a fresh water inlet regulating valve 9, a concentrated water inlet regulating valve 10, an electrode water inlet regulating valve 11, a fresh water inlet mass flowmeter 12, a concentrated water inlet mass flowmeter 13, an electrode water inlet mass flowmeter 14, a membrane module inlet resistivity meter 15, a membrane module product water resistivity meter 16, a membrane module product water discharge mass flowmeter 17, a membrane module product water discharge regulating valve 18, a membrane module product water reflux mass flowmeter 19, a membrane module product water reflux regulating valve 20, and a membrane module DC power supply control unit 21.

[0027] Among them, on one side of the continuous electrodeionization membrane module 8, a fresh water inlet, a concentrated water inlet, and an electrode water inlet are provided, and on the other side, a product water outlet, a concentrated water outlet, and an electrode water outlet of the continuous electrodeionization membrane module 8 are provided. A membrane module DC power supply control unit 21 is provided on the top of the continuous electrodeionization membrane module 8.

[0028] The granular filter 1 is connected to the inlet of the reverse osmosis device 4 via the ultraviolet chlorine residual decomposer 2 and the reverse osmosis feed water pump 3. The outlet of the reverse osmosis device 4 is connected to the inlet of the hybrid water tank 5. The outlet of the hybrid water tank 5 is connected to the inlet of the membrane module precision filter 7 via the membrane module feed water pump 6. The outlet of the membrane module precision filter 7 is divided into three paths. One path is connected to the fresh water inlet of the continuous electrodeionization membrane module 8 via the fresh water inlet regulating valve 9 and the fresh water inlet mass flowmeter 12. One path is connected to the concentrated water inlet of the continuous electrodeionization membrane module 8 via the concentrated water inlet regulating valve 10 and the concentrated water inlet mass flowmeter 13. One path is connected to the electrode water inlet of the continuous electrodeionization membrane module 8 via the electrode water inlet regulating valve 11 and the electrode water inlet mass flowmeter 14. Among them, according to the conductivity of the tap water, the reverse osmosis device 4 can be made into a single-stage reverse osmosis or a two-stage reverse osmosis.

[0029] The water production outlet of the continuous electrodeionization membrane module 8 is connected to the inlet of the membrane module water production resistivity meter 16. The outlet of the membrane module water production resistivity meter 16 is divided into two paths. One path is connected to the inlet of the hybrid water tank 5 via the membrane module water production return mass flowmeter 19 and the membrane module water production return regulating valve 20. The other path is connected to the membrane module water production discharge regulating valve 18 via the membrane module water production discharge mass flowmeter 17.

[0030] The tap water first enters the granular filter 1. The granular filter 1 filters the particulate matter in the tap water, such as rust, sand particles and other particulate matter. When the pressure difference of the granular filter 1 reaches a certain value, an alarm is given to remind the operator to backwash or replace the filter element. The water production outlet of the granular filter 1 is connected to the water inlet of the ultraviolet chlorine residual decomposer 2. The ultraviolet chlorine residual decomposer 2 photolyzes and adsorbs the chlorine residual in the tap water. The water production outlet of the ultraviolet chlorine residual decomposer 2 is connected to the water inlet of the reverse osmosis feed water pump 3. The outlet of the reverse osmosis feed water pump 3 is connected to the reverse osmosis device 4. The reverse osmosis device 4 is used to provide the pressure required for reverse osmosis operation and pre-desalt the tap water. The produced water of the reverse osmosis device 4 enters the hybrid water tank 5 and is fully mixed with the produced water of the continuous electrodeionization membrane module 8. The mixing is carried out by hydraulic force to reduce energy consumption. An overflow partition is arranged in the hybrid water tank 5. The overflow partition divides the space in the hybrid water tank 5 into a mixing area and a water absorption area. The height of the overflow partition is two-thirds of the height of the hybrid water tank 5. The mixed water enters the water absorption area of the hybrid water tank 5 through the overflow partition. A swirl preventer is arranged in the water absorption area of the hybrid water tank 5 to prevent air from entering the membrane module feed water pump 6, thereby protecting the membrane module feed water pump 6. The water outlet of the hybrid water tank 5 is connected to the membrane module feed water pump 6. The outlet of the membrane module feed water pump 6 is connected to the inlet of the membrane module precision filter 7 to further finely filter the incoming water and protect the subsequent continuous electrodeionization membrane module 8.

[0031] An inlet conductivity meter 15 is arranged at the water inlet of the continuous electrodeionization membrane module to continuously and on-line monitor the conductivity of the incoming water. If the conductivity of the incoming water is greater than 20 μS / cm, an alarm is given.

[0032] Example 1

[0033] A fresh water inlet regulating valve 9 and a fresh water inlet mass flowmeter 12 are successively installed on the fresh water inlet pipe of the continuous electrodeionization membrane module 8. The fresh water inlet regulating valve 9 is adjusted to make the flow rate of the fresh water inlet mass flowmeter 12 5000 kg / h.

[0034] A concentrated water inlet regulating valve 10 and a concentrated water inlet mass flowmeter 13 are successively installed on the concentrated water inlet pipe of the continuous electrodeionization membrane module 8. The concentrated water inlet regulating valve 9 is adjusted to make the flow rate of the concentrated water inlet mass flowmeter 13 500 kg / h.

[0035] An electrode water inlet regulating valve 11 and an electrode water inlet mass flowmeter 14 are successively installed on the electrode water inlet pipe of the continuous electrodeionization membrane module 8. The electrode water inlet regulating valve 11 is adjusted to make the flow rate of the electrode water inlet mass flowmeter 14 100 kg / h.

[0036] A fresh water conductivity meter 16 and a membrane module product water discharge mass flowmeter 17 are installed on the fresh water production pipe of the continuous electrodeionization membrane module 8. A membrane module product water return mass flowmeter 19 and a fresh water return regulating valve 20 are installed on the fresh water return pipeline. Through the coordinated adjustment of the membrane module product water discharge regulating valve 18 and the fresh water return regulating valve 20, the flow rate of the membrane module product water discharge mass flowmeter 17 is made 1000 kg / h, and the flow rate of the membrane module product water return mass flowmeter 19 is made 4000 kg / h.

[0037] The test system of the present invention has three functions. One is to control the amount of return water and save the amount of water for the transformation test. The second is to improve the quality of the transformation inlet water of the continuous electrodeionization membrane module 8 and shorten the regeneration time. The third is to discharge part of the product water because high molecular organic substances will dissolve out during the first transformation of the ion exchange resin, and this part of the dissolved substances is discharged to improve the quality of the product water during the subsequent actual operation of the product.

[0038] The transformation test method based on the above-mentioned type of test system in the present invention is as follows: The particulate impurities in tap water are mechanically filtered in the particle filter 1. After the differential pressure of the particle filter 1 reaches a certain value, manual flushing or replacement of the filter column is carried out. After the particle filter 1, the residual chlorine in the water is decomposed. The ultraviolet residual chlorine decomposer 2 is internally provided with multi-spectrum ultraviolet rays, which can effectively decompose the residual chlorine in tap water. The decomposition removal rate is generally above 90%, and the dissolved organic matter is adsorbed. When the differential pressure reaches a certain value, the internal filter element is replaced. After the decomposition of residual chlorine and the adsorption of organic matter, the subsequent reverse osmosis device 4 and the continuous electrodeionization membrane block 8 can be protected. After the residual chlorine in tap water is decomposed, it enters the reverse osmosis device 4 through the reverse osmosis feed pump 3 for pre-desalination. Generally, the recovery rate is controlled above 75%. If the salt content of tap water is relatively high, two-stage reverse osmosis devices can be directly connected in series to ensure that the conductivity of the produced water is less than 20 μS / cm. The produced water of the reverse osmosis device 4 and the produced water of the continuous electrodeionization membrane block 8 enter the hybrid water tank 5 together. The hybrid water tank 5 is internally provided with a mixing zone and a water absorption zone. An overflow partition is provided directly between the two zones to ensure the hydraulic mixing time in the mixing zone. The produced water of the hybrid water tank 5 passes through the membrane block feed pump 6 and the membrane block precision filter 7 and enters the inlet pipeline of the continuous electrodeionization membrane block 8. The membrane block precision filter 7 is a protection device that filters out particles larger than 5 μm to protect the continuous electrodeionization membrane block 8. The inlet pipe of the continuous electrodeionization membrane block 8 is divided into three distribution water pipes, namely the fresh water inlet pipe, the concentrated water inlet pipe, and the electrode water inlet pipe. A fresh water inlet regulating valve 9 is provided on the fresh water inlet pipe, a concentrated water inlet regulating valve 10 is provided on the concentrated water inlet pipe, and an electrode water inlet regulating valve 11 is provided on the electrode water inlet pipe. The water volume is adjusted through the fresh water inlet regulating valve 9, the concentrated water inlet regulating valve 10, the electrode water inlet regulating valve 11, and the valves of the produced water pipeline of the continuous electrodeionization membrane block 8, so that the flow rates of the membrane block produced water discharge mass flowmeter 17, the membrane block produced water return mass flowmeter 19, the concentrated water inlet mass flowmeter 13, and the electrode water inlet mass flowmeter 14 meet the requirements.

[0039] In the continuous electrodeionization membrane block, under the action of a direct current, the water flow is electrolytically dissociated, and the dissociated hydrogen ions and hydroxide ions are used to transform and regenerate the ion exchange resin. The sodium-type cation exchange resin is converted into the hydrogen type, and the chloride-type anion exchange resin is converted into the hydroxide type.

[0040] After the flow rate is stably operated for 0.5 h, the membrane block DC power supply control unit 20 is started, and the current of the continuous electrodeionization membrane block 8 is adjusted to 3.5 A and the voltage is adjusted to 300 V for transformation regeneration and testing. The transformation time of the continuous electrodeionization product to be tested is within 6 h. At the same time, the resistance of the product water is not less than 15 MΩ·cm, which is a qualified product.

[0041] The present invention utilizes the water return of the continuous electrodeionization membrane module 8, which can save the water volume used in the transformation test, improve the water quality of the influent of the continuous electrodeionization membrane module 8, and shorten the transformation test time.

[0042] Preferably, an ultraviolet residual chlorine disconnector is provided in the pretreatment unit, which can disinfect the residual chlorine in the water. At the same time, part of the dissolved organic matter can be removed through the internal adsorption column to protect the subsequent reverse osmosis device 4 and the continuous electrodeionization membrane module 8.

[0043] Preferably, the water produced by the continuous electrodeionization membrane module 8 can be returned through the regulating valve and the reflux regulating valve. Generally, more than 80% of the returned water is recycled, and 20% is discharged to discharge the organic matter dissolved in the body during the transformation and regeneration of the ion exchange resin.

[0044] Preferably, the membrane module DC power supply control unit 20 is interlocked with the fresh water influent flowmeter 12, the concentrated water influent flowmeter 13, and the electrode water influent flowmeter 14. When the flow rates of the fresh water influent flowmeter 12, the concentrated water influent flowmeter 13, and the electrode water influent flowmeter 14 are lower than 80% of the rated flow rate, an alarm is given and the power is automatically cut off to protect the continuous electrodeionization membrane module 8. During the transformation test, the recovery rate of the membrane module is controlled at 90%, and the resistance of the water produced by the continuous electrodeionization membrane module 8 reaches 15 MΩ·cm or more within 6 hours.

[0045] Preferably, a mixing zone and a water absorption zone are provided inside the hybrid water tank 5, and an overflow partition is provided in the middle to ensure full mixing of the influent of the hybrid water tank and the returned water of the membrane module product water, and automatic mixing is achieved by relying on the hydraulic conditions to reduce energy consumption.

[0046] Preferably, for the accuracy of the transformation test, all the flowmeters in this system adopt mass flowmeters, and the membrane module DC power supply control unit 20 of the membrane module can automatically calculate the recovery rate P, the conductivity removal rate M, and the product water resistance value N of the continuous electrodeionization membrane module 8 of the system according to the system settings.

[0047] The influent of the transformation test system is municipal tap water, with guaranteed water quality and sufficient water supply.

[0048] To eliminate the oxidative damage of the residual chlorine in the tap water to the membrane, an ultraviolet residual chlorine disconnector is provided in the pretreatment unit to disinfect the residual chlorine in the water by using photons. The residual chlorine in the municipal tap water is about 0.5 mg / L. Through the disinfection by photons, more than 90% can be removed, ensuring that the residual chlorine in the influent of the reverse osmosis device 4 and the continuous electrodeionization membrane module 8 is less than 0.1 mg / L. The principle of photon disinfection of residual chlorine is as follows:

[0049] 2HOCl + 2hv → O2 + 2HCl

[0050] 2OCl - + 2hv → O2 + 2Cl-

[0051] Meanwhile, the pretreatment unit desalinates the tap water to meet the requirements of the influent conductivity for continuous electrodeionization. Under the action of DC current and voltage, the transformation test unit dissociates water in the continuous electrodeionization module 8, and the dissociated hydrogen ions and hydroxide ions regenerate the ion exchange resin by transformation. The hydrolysis dissociation is as follows:

[0052] H2O→H +1 +OH -1

[0053] Since the single-unit water volume of the continuous electrodeionization module 8 is small, in order to accurately measure the recovery rate and water consumption of continuous electrodeionization, a mass flowmeter is used to measure the water volume to ensure the accuracy of the measured flow rate.

[0054] The influent water quality pretreatment unit is used to ensure that the influent water quality of the system meets the requirements for particulate matter. The tap water needs to be filtered through a particle filter to filter out particulate matter and suspended matter such as rust and sand grains.

[0055] The transformation test system of the present invention can control the recovery rate of the continuous electrodeionization module 8 to 90%. Considering that a small amount of organic macromolecular substances dissolve out during the first transformation regeneration of the ion exchange resin, 20% of the rated water production is discharged.

[0056] In order to save water consumption, 80% of the rated water production of the continuous electrodeionization module 8 is recycled.

[0057] In the present invention, the make-up water for reverse osmosis used is 20% of the rated influent water volume of the continuous electrodeionization module 8.

[0058] The continuous electrodeionization module 8 can adopt a constant current mode. Under the constant current mode, the DC current is 3.5 A and the starting voltage is 300 V.

[0059] The continuous electrodeionization module 8 can also adopt a constant voltage mode according to the requirements of continuous electrodeionization. Under the constant voltage mode, the DC voltage is 450 A and the starting current is 2 A.

[0060] By using the module DC power supply control unit 21, the flowmeter and conductivity can be automatically calculated, and at the same time, it has a low-flow low-protection function.

[0061] The present invention can shorten the transformation test time of the continuous electrodeionization module to 6 hours, saving 50% of the time and promoting industrial production.

[0062] The fresh water inlet flow rate Q1, concentrated water inlet flow rate Q2, electrode water inlet flow rate Q3, fresh water return flow rate Q4, and fresh water discharge flow rate Q5 of the continuous electrodeionization membrane module 8 are all in kg / h. The conductivity of the feed water to the membrane module is C1, and the conductivity of the product water of the membrane module is C2, with the unit of μS / cm. Then, the recovery rate P of the continuous electrodeionization membrane module 8 is calculated as follows:

[0063] P = (Q4 + Q5) / (Q1 + Q2 + Q3 + Q4 + Q5) * 100% (1)

[0064] In the formula, P is the recovery rate of the continuous electrodeionization membrane module, Q1 is the fresh water inlet flow rate, Q2 is the concentrated water inlet flow rate, Q3 is the electrode water inlet flow rate, Q4 is the fresh water return flow rate, and Q5 is the fresh water discharge flow rate. The unit of the flow rate is kg / h;

[0065] The fresh water inlet flow rate Q1 is collected by the fresh water inlet mass flowmeter 12, the concentrated water inlet flow rate Q2 is collected by the concentrated water inlet mass flowmeter 13, the electrode water inlet flow rate Q3 is collected by the electrode water inlet mass flowmeter 14, the fresh water return flow rate Q4 is collected by the membrane module product water return mass flowmeter 19, and the fresh water discharge flow rate Q5 is collected by the membrane module product water discharge mass flowmeter 17.

[0066] During the transformation test, it is necessary to control the recovery rate P = 90%;

[0067] M = (C1 - C2) ÷ C1 * 100% (2)

[0068] In the formula, M is the conductivity removal rate. Generally, the conductivity C1 of the feed water to the continuous electrodeionization membrane module and the conductivity C2 of the product water of the continuous electrodeionization membrane module are controlled not to be greater than 20 μS / cm;

[0069] N = 1 ÷ C2 (3)

[0070] In the formula, N is the resistivity of the product water, with the unit of MΩ·cm. The N value equal to or greater than 15 MΩ·cm is qualified;

[0071] The recovery rate P, conductivity removal rate M, and resistivity N value of the product water are automatically calculated by the module DC power supply control unit 21.

[0072] During the transformation test, first control the recovery rate P of the control system = 90%, which is achieved through the regulating valves at the inlet and outlet. When the recovery rate is adjusted to 90%, at the same time, control the pressure difference at each inlet as follows: the fresh water inlet pressure is 0.20 Kg / cm higher than the concentrated water inlet pressure 2 , and the fresh water inlet pressure is 0.20 Kg / cm higher than the electrode water inlet pressure 2 .

[0073] After running for 0.5 h, turn on the DC power supply and set the following parameters simultaneously: voltage 300 V, current 3.5 A. Conduct continuous operation tests. A qualified product is one where the resistance of the produced water reaches 15 MΩ·cm or more within 6 hours (test results under the condition that the product recovery rate is 90%).

[0074] To illustrate this transformation test system, an example is given below. Take the general-purpose continuous electrodeionization membrane module on the market as an example (its rated water production flow rate is 5000 kg / h).

[0075] See Figure 2 , the total influent flow rate of the continuous electrodeionization membrane module is 5600 kg / h, among which the fresh water influent flow rate is 5000 kg / h, the concentrated water influent flow rate is 500 kg / h, the electrode water influent flow rate is 100 kg / h, the water production flow rate is 5000 kg / h, and the produced water discharge flow rate is 1000 kg / h. The membrane module recovery rate is 5000 / 5600 = 90%. Using the reflux-type transformation test method in the present invention, the required influent flow rate after water balance calculation is 2133 kg / h.

[0076] See Figure 3 , the total influent flow rate of the continuous electrodeionization membrane module is 5600 kg / h, among which the fresh water influent flow rate is 5000 kg / h, the concentrated water influent flow rate is 500 kg / h, the electrode water influent flow rate is 100 kg / h, the water production flow rate is 5000 kg / h and all of it is discharged. The membrane module recovery rate is 5000 / 5600 = 90%. Using the conventional transformation test scheme, the required influent flow rate after water balance calculation is 7467 kg / h.

[0077] By comparing the above two methods, it can be seen that the test method of the present invention saves 5334 kg / h of water compared with the conventional transformation test method, and the saving ratio is 71%, with obvious effects.

[0078] In the present invention, the influent water quality requirements and product water quality requirements during the regeneration of the continuous electrodeionization module are for transformation tests under the same reference condition of a 90% recovery rate. Conduct continuous tests within 6 hours without interruption, and the produced water resistance of the continuous electrodeionization is not less than 15 MΩ·cm. It is a qualified product, meeting the performance requirements of the continuous electrodeionization product for industrial production, and providing guarantee for the preparation of pure water and ultrapure water in various industries.

[0079] The present invention adopts a reflux method to partially reflux the produced water of the continuous electrodeionization membrane module. The reflux water is fully mixed with the produced water of the reverse osmosis and then used as the influent water of the continuous electrodeionization membrane module, improving the influent water quality of the membrane module and being beneficial to saving water and shortening the transformation time.

[0080] The above are only examples of the implementation steps of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A transformation test method for a continuous electrodeionization membrane module, characterized in that It includes the following steps: The transformation test system of the continuous electrodeionization membrane block adopted by the method includes a raw water quality pretreatment unit and a transformation test unit. The transformation test unit includes a hybrid water tank (5) and a continuous electrodeionization membrane block (8). The raw water quality pretreatment unit is connected to the inlet of the hybrid water tank (5). The outlet of the hybrid water tank (5) is connected to the inlet of the continuous electrodeionization membrane block (8), and the outlet of the continuous electrodeionization membrane block (8) is connected to the inlet of the hybrid water tank (5). The outlet of the hybrid water tank (5) is connected to the inlet of the continuous electrodeionization membrane block (8) through a membrane block feed water pump (6), a membrane block precision filter (7), and a membrane block inlet water resistivity meter (15). The continuous electrodeionization membrane block (8) is provided with a fresh water inlet, a concentrated water inlet, and an electrode water inlet. The outlet of the membrane block inlet water resistivity meter (15) is divided into three paths. One path is connected to the fresh water inlet of the continuous electrodeionization membrane block (8) through a fresh water inlet regulating valve (9) and a fresh water inlet mass flowmeter (12). One path is connected to the concentrated water inlet of the continuous electrodeionization membrane block (8) through a concentrated water inlet regulating valve (10) and a concentrated water inlet mass flowmeter (13). One path is connected to the electrode water inlet of the continuous electrodeionization membrane block (8) through an electrode water inlet regulating valve (11) and an electrode water inlet mass flowmeter (14). The continuous electrodeionization membrane block (8) is provided with a product water outlet, a concentrated water outlet, and an electrode water outlet. The product water outlet is connected to the inlet of a membrane block product water resistivity meter (16). The outlet of the membrane block product water resistivity meter (16) is divided into two paths. One path is connected to the inlet of the hybrid water tank (5) through a membrane block product water return mass flowmeter (19) and a membrane block product water return regulating valve (20). The other path is discharged after passing through a membrane block product water discharge mass flowmeter (17) and a membrane block product water discharge regulating valve (18). Valves are provided at the concentrated water outlet and the electrode water outlet. Tap water is filtered, dechlorinated, and pre-desalted by the raw water quality pretreatment unit and then enters the hybrid water tank (5), where it is mixed with the fresh water produced by the continuous electrodeionization membrane block (8). The mixed water is electrolytically dissociated in the continuous electrodeionization membrane block (8) after secondary filtration. The dissociated hydrogen ions and hydroxide ions are used to transform and regenerate the ion exchange resin. The sodium-type cation exchange resin is converted to the hydrogen type, and the chloride-type anion exchange resin is converted to the hydroxide type. The fresh water produced by the continuous electrodeionization membrane block (8) returns to the hybrid water tank (5), and the residual chlorine after dechlorination is less than 0.1 mg / L. The conductivity of the mixed water is less than or equal to 20 µS / cm. In 6 hours, the resistivity of the water produced by the continuous electrodeionization membrane block (8) reaches more than 15 MΩ·cm, and 80% of the rated water production of the continuous electrodeionization membrane block (8) is recycled.

2. The transformation test method of a continuous electrodeionization membrane block according to claim 1, characterized in that The raw water quality pretreatment unit includes a connected granular filter (1), an ultraviolet residual chlorine disconnector (2), a reverse osmosis feed water pump (3), and a reverse osmosis device (4). The reverse osmosis device (4) is connected to the hybrid water tank (5).

3. The transformation test method of a continuous electrodeionization membrane block according to claim 1, characterized in that, At the top of the continuous electrodeionization membrane module (8), there is a membrane module DC power supply control unit (21), and the fresh water inlet mass flowmeter (12), the concentrated water inlet mass flowmeter (13) and the electrode water inlet mass flowmeter (14) are connected to the membrane module DC power supply control unit (21).

4. The transformation test method of a continuous electrodeionization membrane module according to claim 1, characterized in that, An overflow partition is provided in the hybrid water tank (5) for dividing the internal cavity of the hybrid water tank (5) into a mixing zone and a water absorption zone. The height of the overflow partition is two-thirds of the height of the hybrid water tank (5), and a swirl preventer is provided in the water absorption zone.

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