CN106474927B - Large-flux roll-type EDI assembly, assembly method thereof and desalination method - Google Patents

Abstract

The invention relates to the field of water treatment equipment, in particular to a large-flux roll-type EDI component, an assembly method and a desalination method thereof. A large-flux roll-type EDI assembly includes: a housing and a membrane core, the housing includes an outer housing, a sealing sleeve and a cover plate, the sealing sleeve and the cover plate form a set of sealing structures, the Two ends of the outer casing are respectively provided with a set of sealing structures, and the sealing sleeve is arranged between the cover plate and the end of the outer casing; the membrane core includes a core body and an end cover, and the core body is arranged on the Inside the outer casing, the end cover is sleeved inside the connection between the sealing sleeve and the outer casing; the sealing sleeve and the end of the outer casing are provided with a first sealing ring, and the sealing sleeve and the cover plate A second sealing ring is arranged between them, and a third sealing ring is arranged between the sealing sleeve and the end cover.

Description

A kind of high-throughput roll-type EDI assembly, its assembly method and desalination method

technical field

The invention relates to the field of water treatment equipment, in particular to a large-flux roll-type EDI component, an assembly method and a desalination method thereof.

Background technique

At present, EDI electrostatic desalination devices mainly include plate EDI and coil EDI. The traditional roll-type EDI is mainly sealed through the top cover and the bottom cover. The standard flow rate of a single membrane module is about 2m ³ /h. Under the same water discharge requirements, the installation and use occupy a large area, the space utilization rate is low, and the cost per ton of water is high. At the same time, it is necessary to use a press for assembly when installing the membrane core, and the production operation requirements are relatively high.

Compared with the traditional plate-and-frame EDI, the coil-type EDI has concentric electric field distribution, higher current efficiency, and lower power consumption; the design of the concentrated and fresh water flow patterns of the coil-type EDI is different from the same flow of the traditional plate-and-frame EDI Designed to better eliminate fouling-causing factors. At the same time, the structural design of the coiled EDI has created concentrated and fresh water flow channel units from the outside to the inside. Different resins can be configured in the same EDI component according to the water quality, which can not only improve the desalination efficiency, but also effectively reduce the cost of ion removal. energy consumption required.

However, the roll-type EDI is made of several pairs of anion-cation exchange membranes rolled into a cylindrical membrane stack, and then the concentrated and fresh water channels are filled with ion-exchange resin, and finally the lower end cover is added to complete the package. During operation, due to the water-swelling characteristics of the ion exchange membrane and ion exchange resin, it is required that the concentricity of the membrane stack is relatively high during the assembly process of the coiled EDI module, so as to ensure that the entire module expands evenly in the circumferential direction, ensuring Component tightness. However, the actual situation is that due to the difference in the water swelling properties of the ion exchange membrane and ion exchange resin at the axial and longitudinal points of the circumference in the entire cylindrical membrane stack, this difference is related to the material of the ion exchange membrane and ion exchange resin. , is also related to the precision of the EDI-on-roll assembly process. The direct result of this difference is the water leakage of the coiled EDI module, and the flow of concentrated and fresh water inside the module, which seriously affects the desalination effect of the module, until the whole module is scrapped. Therefore, there is an urgent need for a roll-type EDI component product with a large processing capacity (throughput) of a single component and long-term reliable operation in the prior art.

Contents of the invention

The purpose of the present invention is to solve the problems in the background technology, and provide a large-flux roll-type EDI component, its assembly method and desalination method.

Above-mentioned technical purpose of the present invention is achieved through the following technical solutions:

A large-flux roll-type EDI assembly includes: a housing and a membrane core, the housing includes an outer housing, a sealing sleeve and a cover plate, the sealing sleeve and the cover plate form a set of sealing structures, the Two ends of the outer casing are respectively provided with a set of sealing structures, and the sealing sleeve is arranged between the cover plate and the end of the outer casing;

The membrane core includes a core body and an end cover, the core body is arranged inside the outer shell, and the end cover is sleeved inside the connection between the sealing sleeve and the outer shell;

A first sealing ring is provided between the sealing sleeve and the end of the outer shell, a second sealing ring is provided between the sealing sleeve and the cover plate, and a third sealing ring is provided between the sealing sleeve and the end cover.

At present, the sealing method of EDI membrane components is mainly to directly seal the two ends of the membrane core through the cover. During the assembly process, a press is required and the concentricity of all components is very high. During the process of shelling, the friction between the sealing ring and the shell is very large. In the process of inserting, the sealing ring will be damaged to a large extent, which is not conducive to the long-term sealing effect of the component. In addition, in the actual practical process, since the exchange resin inside the membrane core needs to be continuously regenerated during use, and this regeneration process is usually uneven, so in actual use, the expansion stress distribution at each point inside the membrane module is uneven. Uniform, resulting in non-axial bending force of the membrane core, while the sealing method of the traditional cover can only achieve the effect of exerting sealing force in the axial direction, so the diameter of a single traditional membrane module is usually below 40cm, once it exceeds this value , After a long-term use of the membrane module sealed by the traditional cover, it is easy to leak and affect the desalination effect.

Through the above structure, the technical solution does not need to use a press during the assembly process, and the sealing ring will not rub against the outer shell for a long distance during assembly, thereby ensuring the reliability of the sealing ring. In addition, during the long-term use of the membrane module, since the outer casing, sealing sleeve and cover plate are a three-layer sealed structure, when the exchange resin is deformed irregularly, the distance between the outer casing and the sealing sleeve may be abnormal. Axial change, that is, the uneven change of the distance between the outer shell and the sealing sleeve makes the axial direction of the outer shell and the sealing sleeve no longer coincide. Similarly, the change between the sealing sleeve and the end cover can also be changed in this way, and in Under the joint action of the first sealing ring, the second sealing ring and the third sealing ring, the occurrence of leakage is avoided. Therefore, the membrane module of this solution reduces the requirements for axial sealing and reduces the difficulty and cost of production.

Preferably, a cathode column is arranged at the center of the core body, and multiple groups of roll-wound membrane units are arranged on the cathode column, and the membrane units include a positive membrane and a negative membrane, and the gap between the positive membrane and the negative membrane is It is a concentrated water chamber, the two ends of the concentrated water chamber are respectively provided with polar water chambers, the fresh water chamber is between the membrane units, the fresh water chamber is filled with exchange resin, and the two ends of the fresh water chamber are provided with grid plates ;

A central pipe is arranged inside the cathode column, and the end of the central pipe passes through the cover plate to form a first outlet. The outer shell is provided with a first inlet, and the cover plates at both ends of the outer shell A second inlet and a second outlet are respectively provided, and an electrode water outlet communicating with the electrode water chamber is arranged on the outer casing.

Adopting the aforementioned sealing structure, the diameter of the membrane core is increased, and the number of membrane units in the membrane core is also increased accordingly. Therefore, the two ends of the concentrated water chamber of the membrane unit are respectively provided with electrode water chambers, which can effectively separate the electrode side. The polar water is collected and discharged to avoid fouling of the membrane core.

Preferably, the end of the membrane unit away from the cathode column is provided with an anode piece, and the end of the membrane unit close to the cathode column is provided with a cathode piece. The anode piece and cathode piece structure is adopted, so that each membrane unit has an independent pressurized electric field after electrification, which improves the water purification effect.

Preferably, an anode cylinder is sheathed on the outer side of the core, and the anode cylinder is provided to effectively ensure the stability of the anode electrification.

Preferably, a fourth sealing ring is provided between the first outlet and the cover plate to ensure the sealing of the first outlet.

Preferably, the sealing sleeve is provided with bosses for positioning the end cap, and the two ends of the outer casing are provided with bosses for connecting the sealing sleeve and the cover plate.

Preferably, the core includes at least seven sets of evenly distributed membrane units.

Preferably, the second inlet and the second outlet are in communication with the concentrated water chamber, and the direction of liquid flow is that the concentrated water enters from the second inlet, flows through the concentrated water chamber, and then is discharged from the second outlet; the central pipe, the second The first outlet and the first inlet are in communication with the fresh water chamber, and the liquid flow direction is as follows: after the purified water enters through the first inlet, it flows through the fresh water chamber and the central pipeline in turn, and then is discharged from the first outlet. Such a flow channel design makes the flow direction of the concentrated water and the water to be purified cross at 90 degrees in the membrane core, which reduces the possibility of fouling inside the membrane unit and improves the purification efficiency.

The current density is related to the current size and the passing area. The area of the anode outside the membrane core of the above-mentioned structure is larger than the area of the cathode in the center of the membrane core, so the current density outside the membrane core is smaller than the current density in the center of the membrane core, so that the entire electric field The potential energy gradually weakens from the inside to the outside in the radial direction of the membrane core, forming various regions that gradually transition. Since the fresh water to be purified contains a variety of different salts, the electrolyzed electrolyte often includes highly active ions such as Ca ²⁺ , Mg ²⁺ , Na ⁺ , Cl ^- , SO ₄ ^2- and HCO ₃ ^- , HSiO ₃ ^- and other less reactive ions. Therefore, by arranging the flow channel and the electric field in the above-mentioned way, various ions can be separated in different regions, effectively preventing fouling of the components, and improving the utilization rate of electric energy.

A method for assembling a large-volume roll-type EDI component, comprising the following steps:

A Assemble the membrane core, attach the positive membrane and the negative membrane to form a membrane unit, wind multiple sets of membrane units onto the cathode column, line the grid between the membrane units during winding, and place the anode cylinder Assembling the outside of the core;

B Assemble the shell, ① insert the membrane core into the shell, and then insert the end caps at both ends of the membrane core, and the end caps are partially inserted into the inside of the outer shell; ② put the third sealing ring on the outer cover of the end cap, The sealing sleeve is set outside the end cover, and the upper and lower ends of the sealing sleeve are equipped with a first sealing ring and a second sealing ring; ③ buckle the lower end cover on the end cover, and inject exchange resin into the fresh water chamber; ④ put the upper end cover Buckled on the end cover, the cover plate, the sealing sleeve and the connecting boss are tightly connected by bolts.

The above assembly method has a simple process, little damage to the sealing ring, and does not need to use a press or other equipment, which reduces the installation cost under the premise of ensuring the service life of the equipment.

Preferably, in the step B, when the two ends of the membrane core are inserted into the end cover, a fourth sealing ring is installed between the first outlet and the cover plate.

A desalination method using the above-mentioned large-flux roll-type EDI component, connecting the electric field cathode at the center of the membrane core, and connecting the electric field anode at the outside of the membrane core, so that an electric field is formed between the middle of the membrane core and the periphery of the membrane core, and fresh water enters from the first inlet The membrane core flows through the fresh water chamber and the central pipe in turn, and is discharged from the first outlet. Concentrated water enters the membrane core from the second inlet, flows into the concentrated water chamber, and is discharged from the second outlet. During the whole process, the fresh water is in the membrane core. The concentrated water flows along the direction perpendicular to the axial direction of the membrane core, while the concentrated water flows in the axial direction of the membrane core, and the concentrated water and fresh water cross flow; the anions and cations in the fresh water move to both sides under the action of the electric field, and the anions pass through the positive membrane , cations pass through the anion membrane and enter the concentrated water chambers on both sides respectively to complete the desalination effect on fresh water.

In the above method, the concentrated water flows in the axial direction, and the fresh water flows in the radial direction. In this flow direction, the concentrated and fresh water is in a completely cross-flow state, which reduces the possibility of fouling inside the membrane unit and improves the purification efficiency; fresh water enters from the outside of the module, flows from the outside to the inside, and flows from the low current density area to the high current density area. Consistent with the desalination sequence of strong and weak ions, the ion with strong electronegativity and easy to remove can be removed in the low current density area, while the ion with weak electronegativity and difficult to remove just flows through the strong current density area. The removal efficiency and current efficiency are improved.

Preferably, the flow direction of concentrated and fresh water is opposite to the above method, that is, the fresh water flows in the axial direction, enters the membrane core from the second inlet, flows into the fresh water chamber, and is discharged from the second outlet; the concentrated water flows in the radial direction, and the concentrated water enters from the first inlet. , after flowing through the concentrated water chamber and the central pipe in turn, it is discharged from the first outlet. In this flow direction, the concentrated and fresh water is also in a completely cross-flow state, which reduces the possibility of fouling inside the membrane unit and improves the purification efficiency; because the fluid can generate Dean flow in the spiral flow channel, the thickness of the diffusion layer will be reduced and the mass transfer process will be strengthened; In addition, the close distance between the plates will generate a strong electric field, which can also increase the ion migration rate, so that on the one hand, the efficiency of electrolytic desalination can be improved, and on the other hand, the possibility of fouling inside the membrane unit can be reduced.

In summary, the beneficial effects of the present invention:

①A large-flux roll-type EDI component according to the present invention, through the roll-type winding membrane core, the Yin-Yang stage set inside and outside, makes the electric field have a change in the strength of the flow direction of the water to be purified, thus completing the detection of different particles Separation step by step, making full use of electric energy, and at the same time alleviating the fouling tendency of the concentrated water chamber.

②A large-flux roll-type EDI module described in the present invention adopts a split flange structure for the shell, which is simple in structure and easy to assemble, and overcomes the leakage problem that is easy to produce in traditional membrane modules, making the diameter of a single membrane module increase. Large, thereby saving system piping and floor space, reducing the cost per ton of water.

③A large-flux roll-type EDI module and its assembly method described in the present invention, the membrane module produced, the flux of a single membrane core can reach more than 4m ³ /h, which reduces the cost per ton of water and saves system The cost of piping and floor space is about 30% lower than that of two 2m ³ /h modules.

④ In the desalination method of a large-flux roll-type EDI module described in the present invention, the concentrated water and fresh water of the membrane unit are completely cross-flow designed, so that when the module is running, the Ca2+ and Mg2+ ions that are easy to form scaling in the membrane stack will flow from the The fresh water inlet begins to migrate through the cation exchange membrane. While migrating to the cathode, it moves to the concentrated water outlet with the water flow, preventing the enrichment of Ca2+ and Mg2+ ions to the negative membrane side of the concentrated water chamber, thereby reducing the concentration of the concentrated water chamber. Possibility of fouling on the negative membrane side.

⑤ In the desalination method of a large-flux roll-type EDI module described in the present invention, the membrane unit has the characteristics of a spiral channel structure and a short distance between the plates, and the fluid can generate a Dean flow in the spiral channel, which will reduce the diffusion layer Thickness, strengthen the mass transfer process; In addition, the close distance between the plates will generate a strong electric field, which can also increase the ion migration rate, so that on the one hand, the efficiency of electrostatic desalination is improved, and on the other hand, the possibility of fouling inside the membrane unit can be reduced sex.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the structural representation of membrane core among the present invention;

Fig. 3 is the enlarged view of A part among the present invention;

Fig. 4 is the enlarged view of B part among the present invention;

Fig. 5 is a schematic diagram of membrane core winding in the present invention.

Detailed ways

The following specific examples are only explanations of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications without creative contribution to the present embodiment as required after reading this specification, but as long as they are within the rights of the present invention All claims are protected by patent law.

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

Example 1:

According to Fig. 1, Fig. 3 and Fig. 4, a large-flux roll-type EDI assembly includes: a housing 1 and a membrane core 2, the housing 1 includes an outer shell 11, a sealing sleeve 12 and a cover plate 13, and a sealing sleeve 12 and a cover plate 13 form a set of sealing structures, and a set of sealing structures are respectively provided at both ends of the outer shell 11, and the sealing sleeve 12 is arranged between the cover plate 13 and the end of the outer shell 11;

The membrane core 2 includes a core body 21 and an end cover 22. The core body 21 is set inside the outer shell 11, and the end cover 22 is sleeved inside the joint between the sealing sleeve 12 and the outer shell 11. The core body 21 includes seven sets of uniformly distributed The membrane unit 3.

A first sealing ring 14 is provided at the end of the sealing sleeve 12 and the outer shell 11 , a second sealing ring 15 is provided between the sealing sleeve 12 and the cover plate 13 , and a third sealing ring 16 is provided between the sealing sleeve 12 and the end cover 22 , A fourth sealing ring 17 is disposed between the first outlet 42 and the cover plate 13 .

The sealing sleeve 12 is provided with a boss 121 for positioning the end cover 22 , and the two ends of the outer casing 11 are provided with bosses 111 for connecting the sealing sleeve 12 and the cover plate 13 .

According to Fig. 2, Fig. 5 shows, the center of core body 21 is provided with cathode column 211, and the membrane unit 3 of multiple roll-type winding is arranged on cathode column 211, and membrane unit 3 comprises positive film 31 and negative film 32, positive film 31 and the negative membrane 32 is a concentrated water chamber 4, the two ends of the concentrated water chamber 4 are respectively provided with a pole water chamber 7, between the membrane units 3 is a fresh water chamber 5, the fresh water chamber 5 is filled with exchange resin 51, the fresh water chamber The two ends of 5 are provided with grid plates 52; the cathode column 211 is provided with a central pipe 41, and the end of the central pipe 41 passes through the cover plate 13 to form a first outlet 42, and the outer shell 11 is provided with a first inlet 43, The cover plates 13 at both ends of the outer casing 11 are respectively provided with a second inlet 61 and a second outlet 62, and the outer casing 11 is provided with an anode water outlet 71 communicating with the anode water chamber 7, and the end of the membrane unit 3 away from the cathode column 211 An anode sheet 33 is provided, and a cathode sheet 34 is provided at one end of the membrane unit 3 close to the cathode column 211 .

In the large-flux volume EDI component, the second inlet 61 and the second outlet 62 are connected with the concentrated water chamber 4, and the liquid flows in the following direction. After the concentrated water enters from the second inlet 61, it flows through the concentrated water chamber 4 and flows from the The outlet 62 is discharged; the central pipe 41, the first outlet 42, and the first inlet 43 are connected with the fresh water chamber 5, and the liquid flow direction is, after the purified water enters from the first inlet 43, it flows through the fresh water chamber 5 and the central pipe 41 in sequence , discharged from the first outlet 42.

Example 2:

The difference from the first embodiment above is that, as shown in FIG. 2 , an anode cylinder 212 is sheathed outside the core body 21 , which can effectively ensure the stability of the anode electrification.

Example 3:

The method for assembling the large-volume roll-type EDI assembly of the above-mentioned embodiment 1 comprises the following steps:

A Assemble the membrane core 2, attach the positive membrane 31 and the negative membrane 32 to form the membrane unit 3, wind multiple sets of membrane units 3 onto the cathode column 211, and line the grid plate 52 between the membrane units 3 during winding, After the winding is completed, assemble the anode cylinder 212 to the outside of the core body 21;

B Assemble the shell, ① Put the membrane core 2 into the outer shell 11, and then insert the end cap 22 at both ends of the membrane core 2, the end cap 22 is partially inserted into the inside of the outer shell 11, and the two ends of the membrane core 2 are inserted into the end cap At 22 o'clock, put the fourth sealing ring 17 in the first outlet 42 and the cover plate 13; The end is equipped with a first sealing ring 14 and a second sealing ring 15; ③ buckle the lower end cover 13 on the end cover 22, and inject exchange resin 51 into the fresh water chamber 5; ④ buckle the upper end cover 13 on the end cover 22 , the cover plate 13, the sealing sleeve 12 and the connecting boss 111 are tightly connected by bolts.

Example 4:

The desalination method of the large-flux roll-type EDI component in the above-mentioned embodiment 1 or 2 is to connect the electric field cathode at the cathode column 211 of the membrane core 2 or the cathode sheet 34, and connect the electric field anode at the anode cylinder 212 or the anode sheet 33 of the membrane core 2, An electric field is formed between the middle of the membrane core 2 and the periphery of the membrane core 2, fresh water enters the membrane core 2 from the first inlet 43, flows through the fresh water chamber 5 and the central pipe 41 in turn, and is discharged from the first outlet 42, and the concentrated water is discharged from the second The inlet 61 enters the membrane core 2, flows into the concentrated water chamber 4, and is discharged from the second outlet 62. During the whole process, the fresh water flows in the membrane core 2 along the direction perpendicular to the axis of the membrane core 2, while the concentrated water flows in the membrane core 2 The core 2 flows in the axial direction, and the concentrated water and fresh water cross-flow; the anions and cations in the fresh water move to both sides under the action of the electric field, the anions pass through the positive membrane 31, and the cations pass through the negative membrane 32, and enter the concentrated water chambers 4 on both sides respectively , to complete the desalination effect of fresh water. Concentrated water flows axially, and freshwater flows radially. In such a flow direction, the concentrated and fresh water is in a completely cross-flow state, which reduces the possibility of fouling inside the membrane unit and improves the purification efficiency; fresh water enters from the outside of the module, flows from the outside to the inside, and flows from the low current density area to the high current density area. Just in line with the desalination sequence of strong and weak ions, strong electronegativity, easy to remove ions can be removed in the low current density area, and weak electronegativity, difficult to remove ions just flow through the strong current density area , improved removal efficiency and current efficiency.

At the same time, the fresh water chamber 5 contains an exchange resin 51, and under the action of an electric field, a part of the water molecules in the fresh water are decomposed into hydrogen ions and hydroxide ions. These hydrogen ions and hydroxide ions continuously regenerate the exchange resin 51 filled in the fresh water chamber 5 . Positively charged cations and negatively charged anions are respectively adsorbed on the corresponding resins, and under the action of the electric field anode and cathode, migrate through the corresponding resins, pass through the positive membrane 31 and the negative membrane 32 into the concentrated water chamber 4 and Get out. The positive membrane 31 only allows anions to pass through, while cations and liquid cannot pass through; the anion membrane 32 only allows anions to pass through, while anions and liquid cannot pass through.

Table 1

Table 1 shows the water treatment parameters of a single membrane core of the membrane module in this embodiment, and Table 2 shows the water treatment parameters of a single membrane core of a traditional 2m ³ /h membrane module.

Table 2

By comparing the data in the table, it can be found that the water production of a single mold core in this scheme has been greatly improved, and the water quality is still similar to that of the traditional membrane module in terms of water resistivity and module pressure drop, thereby improving the water treatment efficiency.

Example 5:

The difference from embodiment 4 is that the flow direction of concentrated and fresh water is opposite to the method in embodiment 4, that is, the fresh water flows in the axial direction, enters the membrane core 2 from the second inlet 61, flows into the fresh water chamber 5, and is discharged from the second outlet 62; Concentrated water flows in the radial direction, and the concentrated water enters from the first inlet 43 , flows through the concentrated water chamber 5 and the central pipe 41 in turn, and is discharged from the first outlet 42 . In such a flow direction, the concentrated and fresh water is also in a completely cross-flow state, which reduces the possibility of fouling inside the membrane unit and improves the purification efficiency; because the fluid can generate Dean flow in the spiral flow channel, the thickness of the diffusion layer will be reduced and the mass transfer process will be enhanced. ;In addition, the close distance between the plates will generate a strong electric field, which can also increase the ion migration rate, so that on the one hand, it can improve the efficiency of electrostatic desalination, and on the other hand, it can reduce the possibility of fouling inside the membrane unit.

Claims (9)

1. A large-flux rolled EDI component comprising: the membrane comprises a shell (1) and a membrane core (2), and is characterized in that the shell (1) comprises a shell body (11), sealing sleeves (12) and a cover plate (13), wherein one sealing sleeve (12) and one cover plate (13) form a group of sealing structures, two ends of the shell body (11) are respectively provided with a group of sealing structures, and the sealing sleeves (12) are arranged between the cover plate (13) and the end part of the shell body (11);

the membrane core (2) comprises a core body (21) and an end cover (22), the core body (21) is arranged in the outer shell (11), and the end cover (22) is sleeved in the connecting part of the sealing sleeve (12) and the outer shell (11);

a first sealing ring (14) is arranged at the end parts of the sealing sleeve (12) and the outer shell (11), a second sealing ring (15) is arranged between the sealing sleeve (12) and the cover plate (13), and a third sealing ring (16) is arranged between the sealing sleeve (12) and the end cover (22);

the sealing sleeve (12) is provided with a boss for positioning the end cover (22), and two ends of the outer shell (11) are provided with connecting bosses for the sealing sleeve (12) and the cover plate (13);

the water yield of the single membrane core (2) is 3.8-4.5m ³ /h；

The cover plate (13), the sealing sleeve (12) and the connecting boss are tightly connected through bolts.

2. The roll type EDI component of claim 1, wherein a cathode column (211) is arranged at the center of the core body (21), a plurality of groups of roll type wound membrane units (3) are arranged on the cathode column (211), the membrane units (3) comprise an anode membrane (31) and a cathode membrane (32), a concentrated water chamber (4) is arranged between the anode membrane (31) and the cathode membrane (32), two ends of the concentrated water chamber (4) are respectively provided with an electrode water chamber (7), a fresh water chamber (5) is arranged between the membrane units (3), the fresh water chamber (5) is filled with exchange resin (51), and two ends of the fresh water chamber (5) are provided with grid plates (52);

be provided with central pipeline (41) in negative pole post (211), the tip of central pipeline (41) is worn out outside apron (13), forms first export (42), be provided with first import (43) on shell body (11), be provided with second import (61) and second export (62) on apron (13) at shell body (11) both ends respectively, be provided with on shell body (11) with utmost point water export (71) that utmost point hydroecium (7) are linked together.

3. A large flux rolled EDI module according to claim 2, characterized in that the end of the membrane unit (3) remote from the cathode column (211) is provided with an anode sheet (33) and the end of the membrane unit (3) close to the cathode column (211) is provided with a cathode sheet (34).

4. A large flux rolled EDI assembly according to claim 2 or 3, characterized by an anode barrel (212) sleeved outside the core (21).

5. A large flux rolled EDI assembly according to claim 4 wherein a fourth seal (17) is disposed between said first outlet (42) and said cover plate (13).

6. A large flux rolled EDI module according to claim 5 wherein said core (21) comprises at least seven groups of equispaced membrane units (3).

7. A method of assembling a large flux roll-type EDI module according to any one of claims 4 to 6, comprising the steps of:

a, assembling a membrane core (2), attaching an anode membrane (31) and a cathode membrane (32) to form membrane units (3), winding a plurality of groups of membrane units (3) on a cathode column (211), lining a grid plate (52) between the membrane units (3) during winding, and assembling an anode cylinder (212) on the outer side of a core body (21) after winding is completed;

b, assembling a shell, (1) sleeving a membrane core (2) into the shell (11), then sleeving end covers (22) at two ends of the membrane core (2), and partially sleeving the end covers (22) into the shell (11); (2) a third sealing ring (16) is sleeved outside the end cover (22), a sealing sleeve (12) is sleeved outside the end cover (22), and a first sealing ring (14) and a second sealing ring (15) are arranged at the upper end and the lower end of the sealing sleeve (12); (3) buckling a lower end cover plate (13) on the end cover (22), and injecting exchange resin (51) into the fresh water chamber (5); (4) and an upper end cover plate (13) is buckled on the end cover (22), and the cover plate (13), the sealing sleeve (12) and the connecting boss are tightly connected through bolts.

8. The method for assembling a large-flux rolled EDI component as claimed in claim 7, wherein in step B, when the membrane core (2) is sleeved on the end cap (22) at both ends, a fourth sealing ring (17) is arranged between the first outlet (42) and the cover plate (13).

9. A desalination method using the large-flux rolled EDI module according to any one of claims 4 to 6, characterized in that an electric field cathode is connected to the center of the membrane core (2), an electric field anode is connected to the outer side of the membrane core (2), so that an electric field is formed between the middle of the membrane core (2) and the outer periphery of the membrane core (2), fresh water enters the membrane core (2) from the first inlet (43), and flows through the fresh water chamber (5) and the central pipe (41) in sequence, and then is discharged from the first outlet (42), concentrated water enters the membrane core (2) from the second inlet (61), and flows into the concentrated water chamber (4), and then is discharged from the second outlet (62), and during the whole process, the fresh water flows in the membrane core (2) in a direction perpendicular to the axial direction of the membrane core (2), and the concentrated water flows in the axial direction of the membrane core (2), and the concentrated water and the fresh water cross-flow; the anions and cations in the fresh water move to two sides under the action of the electric field, the anions pass through the cation membrane (31), the cations pass through the anion membrane (32) and respectively enter the concentrated water chambers (4) at two sides, and the desalting effect of the fresh water is finished.

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