System and method for concentrating ammonium chloride solution and co-producing fresh water

Abstract

The invention provides a system and a method for concentrating an ammonium chloride solution and co-producing fresh water. The system comprises a fresh water system, a concentrated water system and a water storage system, the fresh water system comprises a sea fresh water system and a brackish water system which are arranged in sequence, the concentrated water system comprises a primary concentration system and a secondary concentration system which are arranged in sequence, and the concentrated water system is connected with the fresh water system. The water storage system comprises a raw water tank, a fresh water tank and a concentrated water tank, the raw water tank is connected with the fresh water system or the concentrated water system, the fresh water tank is connected with the brackish water system, and the concentrated water tank is connected with the concentrated water system. The system and the method disclosed by the invention have the advantages of low energy consumption, no wastewater discharge and the like, and the ammonium chloride concentrated solution of which the TDS is greater than or equal to 170000 mg / L and the fresh water of which the TDS is less than or equal to 300 mg / L can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of saline wastewater treatment, and in particular to a system and method for concentrating ammonium chloride solution and co-producing fresh water. Background Art

[0002] The concentration of ammonium chloride solution has always been a rather troublesome problem in modern chemical industry. Traditional concentration methods include evaporation crystallization method and membrane concentration method. The evaporation crystallization method is to heat the ammonium chloride solution to the boiling point to make the solute concentration in the solution reach saturation, and then slowly evaporate the solution under constant temperature conditions to make the solute gradually crystallize out. The membrane concentration method is to use a separation membrane to achieve directional separation of ammonium chloride and liquid so as to achieve the concentration effect.

[0003] However, the evaporation crystallization method has high energy consumption, and due to the presence of chloride ions in the ammonium chloride solution, special stainless steel materials need to be selected for the evaporation crystallization equipment, resulting in high cost; although the membrane concentration method can economically concentrate the ammonium chloride solution, traditional pressure membranes can only concentrate the ammonium chloride solution to about 120,000 mg / L. To further increase the concentration, electrodialysis membranes need to be used for concentration under the action of electric drive, which also has problems such as high energy consumption and high investment. Therefore, it is particularly important to develop a method for concentrating ammonium chloride solution with low energy consumption and low investment.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a system and method for concentrating ammonium chloride solution and co-producing fresh water, which have the advantages of low energy consumption and no wastewater discharge, and can obtain an ammonium chloride concentrated solution with TDS≥170,000 mg / L and fresh water with TDS≤300 mg / L.

[0006] The present invention provides a system for concentrating ammonium chloride solution and co-producing fresh water, which includes a fresh water system, a concentrated water system and a water storage system. The fresh water system includes a seawater desalination system and a brackish water system arranged in sequence. The concentrated water system includes a primary concentration system and a secondary concentration system arranged in sequence. The concentrated water system is connected to the fresh water system. The water storage system includes a raw water tank, a fresh water tank and a concentrated water tank. The raw water tank is connected to the fresh water system or the concentrated water system. The fresh water tank is connected to the brackish water system. The concentrated water tank is connected to the concentrated water system.

[0007] There are no strict restrictions on the setting methods of the fresh water system, concentrated water system and water storage system, which can be reasonably set according to the TDS of the ammonium chloride solution to be treated in the raw water tank; for example, when the TDS of the ammonium chloride solution to be treated in the raw water tank ≤ 45000 mg / L, the raw water tank is sequentially connected to the fresh water system and the concentrated water system; when the TDS of the ammonium chloride solution to be treated in the raw water tank > 45000 mg / L, the raw water tank is sequentially connected to the concentrated water system and the fresh water system. In addition, the seawater desalination system and brackish water system in the fresh water system can be set to one stage or multiple stages as needed, and the concentrated water system can be set to two stages or multiple stages as needed.

[0008] In one embodiment, the raw water tank is connected to the seawater desalination system, the fresh water outlet of the seawater desalination system is connected to the brackish water system, the concentrated water outlet of the seawater desalination system is connected to the first-stage concentration system through an intermediate water tank, the fresh water outlet and the concentrated water outlet of the brackish water system are respectively connected to the fresh water tank and the seawater desalination system, the fresh water outlet and the concentrated water outlet of the first-stage concentration system are respectively connected to the raw water tank and the second-stage concentration system, and the fresh water outlet and the concentrated water outlet of the second-stage concentration system are respectively connected to the intermediate water tank and the concentrated water tank. The system with this setting method can be used to treat the ammonium chloride solution to be treated with a relatively low TDS (for example, TDS ≤ 45000 mg / L), and at this time it is mainly used to concentrate the ammonium chloride solution to be treated.

[0009] In another method, the raw water tank is connected to the first-stage concentration system, the concentrated water outlet of the first-stage concentration system is connected to the concentrated water tank, the fresh water outlet of the first-stage concentration system is connected to the second-stage concentration system through an intermediate water tank, the fresh water outlet and the concentrated water outlet of the second-stage concentration system are respectively connected to the seawater desalination system and the raw water tank, the fresh water outlet and the concentrated water outlet of the seawater desalination system are respectively connected to the brackish water system and the intermediate water tank, and the fresh water outlet and the concentrated water outlet of the brackish water system are respectively connected to the fresh water tank and the seawater desalination system. The system with this setting method can be used to treat the ammonium chloride solution to be treated with a relatively high TDS (for example, TDS > 45000 mg / L), and at this time it is mainly used to prepare fresh water.

[0010] The seawater desalination system mainly uses seawater desalination membranes for treatment; among them, the material of the seawater desalination membrane is a polyamide composite material, and the industrial 8″ spiral wound membrane element of Guangdong Ausibo Membrane Material Technology Co., Ltd. is used, with the model of SW-8040-HR; the operating pressure of the seawater desalination membrane is 1.0 - 7.0 MPa, for example 5.0 - 6.0 MPa, the operating temperature ≤ 50 °C, for example room temperature; the TDS of the concentrated water outlet of the seawater desalination system ≥ 50000 mg / L, and the TDS of the fresh water outlet of the seawater desalination system ≤ 2300 mg / L.

[0011] The brackish water system is mainly treated with brackish water membranes; among them, the material of the brackish water membrane is a polyamide composite material, using an 8" spiral wound membrane element for industrial use from Guangdong Ausibo Membrane Material Technology Co., Ltd., with the model BW-8040-400; the operating pressure of the brackish water membrane is 1.0 - 4.0 MPa, for example 3.0 MPa, the operating temperature ≤ 50 °C, for example room temperature; the TDS of the concentrated water effluent of the brackish water system ≥ 5000 mg / L, and the TDS of the fresh water effluent of the brackish water system ≤ 300 mg / L.

[0012] The primary concentration system is mainly treated with primary concentration membranes; among them, the material of the primary concentration membrane is a polyamide composite material, using an 8" spiral wound membrane element for industrial use from Guangdong Ausibo Membrane Material Technology Co., Ltd., with the model CCT-8040-RC1; the operating pressure of the primary concentration membrane is 1.0 - 8.0 MPa, for example 7.0 - 8.0 MPa, the operating temperature ≤ 50 °C, for example room temperature; the TDS of the concentrated water effluent of the primary concentration system ≥ 110000 mg / L, and the TDS of the fresh water effluent of the primary concentration system ≤ 73000 mg / L.

[0013] The secondary concentration system is mainly treated with secondary concentration membranes; among them, the material of the secondary concentration membrane is a polyamide composite material, using an 8" spiral wound membrane element for industrial use from Guangdong Ausibo Membrane Material Technology Co., Ltd., with the model CCT-8040-RC2; the operating pressure of the secondary concentration membrane is 1.0 - 9.0 MPa, for example 7.0 - 8.0 MPa, the operating temperature ≤ 50 °C, for example room temperature; when used for concentration, the TDS of the concentrated water effluent of the secondary concentration system ≥ 170000 mg / L, and the TDS of the fresh water effluent of the secondary concentration system ≤ 80000 mg / L.

[0014] The present invention also provides a method for concentrating ammonium chloride solution and co-producing fresh water in parallel, which uses the above system to treat the ammonium chloride solution to be treated for ammonium chloride solution concentration and co-produce fresh water in parallel.

[0015] The method of the present invention can select a system with a suitable structure for treatment according to actual needs; among them, the TDS of the ammonium chloride solution to be treated can be 400 - 150000 mg / L; the TDS of the concentrated ammonium chloride solution ≥ 170000 mg / L, and the TDS of the fresh water ≤ 300 mg / L.

[0016] The system and method for concentrating ammonium chloride solution and co-producing fresh water in parallel of the present invention concentrate the ammonium chloride aqueous solution and obtain fresh water by means of membrane treatment; compared with the traditional membrane concentration system, the system and method of the present invention can concentrate the ammonium chloride solution to a higher concentration, and can obtain an ammonium chloride concentrated solution with TDS ≥ 170000 mg / L and fresh water with TDS ≤ 300 mg / L, having advantages such as low energy consumption and no wastewater discharge. Description of the Drawings

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Structural schematic diagram of the system for producing concentrated ammonium chloride solution and co-producing fresh water in Example 1;

[0019] Figure 2 Process flow chart of the method for producing concentrated ammonium chloride solution and co-producing fresh water in Example 1;

[0020] Figure 3 Structural schematic diagram of the system for producing concentrated ammonium chloride solution and co-producing fresh water in Example 2;

[0021] Figure 4 Process flow chart of the method for producing concentrated ammonium chloride solution and co-producing fresh water in Example 2.

[0022] Explanation of reference numerals:

[0023] 1: Seawater desalination system; 2: Brackish water system; 3: First-stage concentration system; 4: Second-stage concentration system; 5: Raw water tank; 6: Fresh water tank; 7: Concentrated water tank; 8: Intermediate water tank. Specific embodiments

[0024] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless otherwise clearly specified in the context, the singular form also includes the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0027] The separation membranes used in each embodiment are as follows:

[0028] Seawater desalination membrane: An 8″ spiral wound membrane element for industrial use from Guangdong Auspere Membrane Materials Technology Co., Ltd., with the model SW-8040-HR;

[0029] Brackish water membrane: An 8″ spiral wound membrane element for industrial use from Guangdong Auspere Membrane Materials Technology Co., Ltd., with the model BW-8040-400;

[0030] First-stage concentration membrane: An 8″ spiral wound membrane element for industrial use from Guangdong Auspere Membrane Materials Technology Co., Ltd., with the model CCT-8040-RC1;

[0031] Second-stage concentration membrane: An 8″ spiral wound membrane element for industrial use from Guangdong Auspere Membrane Materials Technology Co., Ltd., with the model CCT-8040-RC2.

[0032] Example 1

[0033] As Figure 1 shown, the system for concentrating ammonium chloride solution and producing fresh water in parallel in this embodiment includes a fresh water system, a concentrated water system, and a water storage system. The fresh water system includes a seawater desalination system 1 and a brackish water system 2 arranged in sequence. The concentrated water system includes a first-stage concentration system 3 and a second-stage concentration system 4 arranged in sequence. The concentrated water system is connected to the fresh water system. The water storage system includes a raw water tank 5, a fresh water tank 6, a concentrated water tank 7, and an intermediate tank 8. The raw water tank 5 is connected to the fresh water system. The fresh water tank 6 is connected to the brackish water system 2. The concentrated water tank 7 is connected to the concentrated water system.

[0034] The system of this embodiment can be used to concentrate the ammonium chloride solution to be treated with a relatively low TDS. The TDS of the ammonium chloride solution to be treated is ≤ 45000 mg / L, for example, 5000 - 30000 mg / L.

[0035] More specifically, the raw water tank 5 is connected to the seawater desalination system 1. The fresh water outlet of the seawater desalination system 1 is connected to the brackish water system 2. The concentrated water outlet of the seawater desalination system 1 is connected to the first-stage concentration system 3 through the intermediate tank 8. The fresh water outlet and the concentrated water outlet of the brackish water system 2 are respectively connected to the fresh water tank 6 and the seawater desalination system 1. The fresh water outlet and the concentrated water outlet of the first-stage concentration system 3 are respectively connected to the raw water tank 5 and the second-stage concentration system 4. The fresh water outlet of the second-stage concentration system 4 is connected to the first-stage concentration system 3 through the intermediate tank 8. The concentrated water outlet of the second-stage concentration system 4 is connected to the concentrated water tank 7.

[0036] The seawater desalination system 1 mainly uses a seawater desalination membrane for treatment; among them, the material of the seawater desalination membrane is a polyamide composite material; the operating pressure of the seawater desalination membrane is 1.0 - 7.0 MPa, and the operating temperature ≤ 50 °C; the influent TDS of the seawater desalination system 1 ≤ 45000 mg / L, for example, it is 5000 - 30000 mg / L; the concentrated water effluent of the seawater desalination system 1 (i.e., seawater desalination concentrated water) TDS ≥ 50000 mg / L, for example, it is 50000 - 60000 mg / L; the fresh water effluent of the seawater desalination system 1 (i.e., seawater desalination fresh water) TDS ≤ 2300 mg / L, further ≤ 2000 mg / L, for example, it is 1500 - 2000 mg / L.

[0037] The brackish water system 2 mainly uses a brackish water membrane for treatment; among them, the material of the brackish water membrane is a polyamide composite material; the operating pressure of the brackish water membrane is 1.0 - 4.0 MPa, and the operating temperature ≤ 50 °C; the influent TDS of the brackish water system 2 is, for example, 1500 - 3000 mg / L; the concentrated water effluent of the brackish water system 2 TDS ≥ 5000 mg / L, for example, it is 5000 - 6000 mg / L; the fresh water effluent of the brackish water system 2 TDS ≤ 300 mg / L, for example, it is 150 - 200 mg / L.

[0038] The primary concentration system 3 mainly uses a primary concentration membrane for treatment; among them, the material of the primary concentration membrane is a polyamide composite material; the operating pressure of the primary concentration membrane is 1.0 - 8.0 MPa, and the operating temperature ≤ 50 °C; the influent TDS of the primary concentration system 3 is, for example, 50000 - 110000 mg / L; the concentrated water effluent of the primary concentration system 3 TDS ≥ 110000 mg / L, for example, it is 130000 - 140000 mg / L; the fresh water effluent of the primary concentration system 3 TDS ≤ 73000 mg / L, for example, it is 20000 - 30000 mg / L.

[0039] The secondary concentration system 4 mainly uses a secondary concentration membrane for treatment; among them, the material of the secondary concentration membrane is a polyamide composite material; the operating pressure of the secondary concentration membrane is 1.0 - 9.0 MPa, and the operating temperature ≤ 50 °C; the influent TDS of the secondary concentration system 4 is, for example, 70000 - 140000 mg / L; the concentrated water effluent of the secondary concentration system 4 TDS ≥ 170000 mg / L, for example, it is 180000 - 190000 mg / L; the fresh water effluent of the secondary concentration system 4 TDS ≤ 80000 mg / L, for example, it is 60000 - 65000 mg / L.

[0040] The system for concentrating ammonium chloride solution and co-producing fresh water in this embodiment uses a seawater desalination system 1, a brackish water system 2, a primary concentration system 3, and a secondary concentration system 4 to concentrate the ammonium chloride aqueous solution and obtain fresh water. Compared with the traditional membrane concentration system, the system in this embodiment can raise the ammonium chloride solution to a higher concentration, and can obtain an ammonium chloride concentrated solution with TDS≥185000mg / L and fresh water with TDS≤200mg / L, having advantages such as low energy consumption and no wastewater discharge.

[0041] Example 2

[0042] The method for concentrating ammonium chloride solution and co-producing fresh water in this embodiment is carried out using the system of Example 1; as Figure 2 shown, the specific steps are as follows:

[0043] 1. Seawater desalination system treatment

[0044] The water quality of the ammonium chloride solution to be treated (i.e., brine) is shown in Table 1; the TDS of this ammonium chloride solution to be treated is 25928mg / L.

[0045] Table 1 Water quality of the ammonium chloride solution to be treated

[0046] Component <![CDATA[Ca 2+ > <![CDATA[Mg 2+ > <![CDATA[Na + > <![CDATA[K + > <![CDATA[NH4 + > <![CDATA[Cl - > Content, mg / L 3101 33 356 40 7887 14511

[0047] The ammonium chloride solution to be treated in the raw water tank 5 first enters the seawater desalination system 1 for treatment, with an operating pressure of 5MPa and an operating temperature of normal temperature during treatment; the seawater desalination concentrated water formed by the treatment enters the primary concentration system 3 through the intermediate water tank 8, and the seawater desalination fresh water enters the brackish water system 2.

[0048] The water quality of the treated seawater desalination fresh water and seawater desalination concentrated water is shown in Table 2; the TDS of the seawater desalination fresh water is 1982.02mg / L, and the TDS of the seawater desalination concentrated water is 51801mg / L.

[0049] Table 2 Water quality of the seawater desalination fresh water and seawater desalination concentrated water

[0050]

[0051] 2. Brackish water system treatment

[0052] The seawater desalination concentrated water enters the brackish water system 2 for treatment to further reduce the salt content of the fresh water, with an operating pressure of 3MPa and an operating temperature of normal temperature during treatment; the brackish water concentrated water formed by the treatment returns to the seawater desalination system 1, and the brackish water fresh water enters the fresh water tank 6.

[0053] The water quality of the treated brackish water fresh water and brackish water concentrated water is shown in Table 3; the TDS of the brackish water fresh water is 186.08mg / L, and the TDS of the brackish water concentrated water is 5563mg / L.

[0054] Table 3 Water Quality of Brackish Water, Fresh Water and Concentrated Brackish Water

[0055]

[0056] 3. Treatment by the primary concentration system

[0057] The concentrated seawater produced by the seawater desalination system 1 enters the primary concentration system 3 through the intermediate water tank 8 for treatment to further increase the ammonium chloride content in the concentrated water. The operating pressure during treatment is 7 MPa, and the operating temperature is normal temperature. The primary concentrated water formed by the treatment enters the secondary concentration system 4, and the primary concentrated fresh water returns to the original water tank 5.

[0058] The water quality of the treated primary concentrated fresh water and primary concentrated water is shown in Table 4; the TDS of the primary concentrated fresh water is 25039 mg / L, and the TDS of the primary concentrated water is 133122 mg / L.

[0059] Table 4 Water Quality of Primary Concentrated Fresh Water and Primary Concentrated Water

[0060]

[0061] 4. Treatment by the secondary concentration system

[0062] The primary concentrated water produced by the primary concentration system 3 enters the secondary concentration system 4 for treatment to further increase the ammonium chloride content in the concentrated water. The operating pressure during treatment is 8 MPa, and the operating temperature is normal temperature. The secondary concentrated water formed by the treatment enters the concentrated water tank 7, and the secondary concentrated fresh water returns to the primary concentration system 3 through the intermediate water tank 8.

[0063] The water quality of the treated secondary concentrated fresh water and secondary concentrated water is shown in Table 5; the TDS of the secondary concentrated fresh water is 62553 mg / L, and the TDS of the secondary concentrated water is 185235 mg / L.

[0064] Table 5 Water Quality of Secondary Concentrated Fresh Water and Secondary Concentrated Water

[0065]

[0066] Example 3

[0067] As Figure 3 shown, the system for concentrating ammonium chloride solution and co-producing fresh water in this example includes a fresh water system, a concentrated water system and a water storage system. The fresh water system includes a seawater desalination system 1 and a brackish water system 2 arranged in sequence. The concentrated water system includes a primary concentration system 3 and a secondary concentration system 4 arranged in sequence. The concentrated water system is connected to the fresh water system. The water storage system includes an original water tank 5, a fresh water tank 6, a concentrated water tank 7 and an intermediate water tank 8. The original water tank 5 is connected to the concentrated water system, the fresh water tank 6 is connected to the brackish water system 2, and the concentrated water tank 7 is connected to the concentrated water system.

[0068] The system of this embodiment can be used to treat the ammonium chloride solution to be treated with a high TDS to prepare fresh water. The TDS of the ammonium chloride solution to be treated is > 45000 mg / L, for example, 100000 - 110000 mg / L.

[0069] More specifically, the raw water tank 5 is connected to the first-stage concentration system 3. The concentrated water outlet of the first-stage concentration system 3 is connected to the concentrated water tank 7. The fresh water outlet of the first-stage concentration system 3 is connected to the second-stage concentration system 4 through the intermediate water tank 8. The fresh water outlet and the concentrated water outlet of the second-stage concentration system 4 are respectively connected to the seawater desalination system 1 and the raw water tank 5. The fresh water outlet of the seawater desalination system 1 is connected to the brackish water system 2. The concentrated water outlet of the seawater desalination system 1 is connected to the second-stage concentration system 4 through the intermediate water tank 8. The fresh water outlet and the concentrated water outlet of the brackish water system 2 are respectively connected to the fresh water tank 6 and the seawater desalination system 1.

[0070] The first-stage concentration system 3 mainly uses a concentration membrane for treatment. Among them, the material of the concentration membrane is a polyamide composite material. The operating pressure of the first-stage concentration membrane is 1.0 - 9.0 MPa, and the operating temperature ≤ 50°C. The inlet TDS of the first-stage concentration system 3 is, for example, 100000 - 110000 mg / L. The concentrated water outlet TDS of the first-stage concentration system 3 ≥ 110000 mg / L, for example, 130000 - 140000 mg / L. The fresh water outlet TDS of the first-stage concentration system 3 ≤ 73000 mg / L, for example, 70000 - 80000 mg / L.

[0071] The second-stage concentration system 4 mainly uses a concentration membrane for treatment. Among them, the material of the second-stage concentration membrane is a polyamide composite material. The operating pressure of the concentration membrane is 1.0 - 8.0 MPa, and the operating temperature ≤ 50°C. The inlet TDS of the second-stage concentration system 4 is, for example, 60000 - 80000 mg / L. The concentrated water outlet TDS of the second-stage concentration system 4 is, for example, 100000 - 110000 mg / L. The fresh water outlet TDS of the second-stage concentration system 4 is, for example, 40000 - 50000 mg / L.

[0072] The seawater desalination system 1 mainly uses a seawater desalination membrane for treatment. Among them, the material of the seawater desalination membrane is a polyamide composite material. The operating pressure of the seawater desalination membrane is 1.0 - 7.0 MPa, and the operating temperature ≤ 50°C. The inlet TDS of the seawater desalination system 1 is, for example, 40000 - 50000 mg / L. The concentrated water outlet TDS of the seawater desalination system 1 ≥ 50000 mg / L, for example, 60000 - 70000 mg / L. The fresh water outlet TDS of the seawater desalination system 1 ≤ 2300 mg / L, for example, 2000 - 2300 mg / L.

[0073] The brackish water system 2 is mainly treated by using brackish water membranes; among them, the material of the brackish water membranes is polyamide composite material; the operating pressure of the brackish water membranes is 1.0 - 4.0 MPa, and the operating temperature ≤ 50 °C; the influent TDS of the brackish water system 2 is, for example, 2000 - 3000 mg / L; the concentrated water effluent TDS of the brackish water system 2 ≥ 5000 mg / L, for example, 8000 - 9000 mg / L; the fresh water effluent TDS of the brackish water system 2 ≤ 300 mg / L, for example, 200 - 250 mg / L.

[0074] The system for concentrating ammonium chloride solution and co-producing fresh water in this embodiment uses a primary concentration system 3, a secondary concentration system 4, a seawater desalination system 1, and a brackish water system 2 to produce fresh water while concentrating the ammonium chloride aqueous solution, and fresh water with TDS ≤ 300 mg / L can be obtained, which has the advantages of low energy consumption and no waste water discharge.

[0075] Example 4

[0076] The method for concentrating ammonium chloride solution and co-producing fresh water in this embodiment is carried out by using the system of Example 3; as Figure 4 shown, the specific steps are as follows:

[0077] 1. Treatment by the primary concentration system

[0078] The water quality of the ammonium chloride solution to be treated (i.e., brine) is shown in Table 6; the TDS of this ammonium chloride solution to be treated is 108679 mg / L.

[0079] Table 6 Water quality of the ammonium chloride solution to be treated

[0080] Component <![CDATA[Ca 2+ > <![CDATA[Mg 2+ > <![CDATA[Na + > <![CDATA[K + > <![CDATA[NH4 + > <![CDATA[Cl - > Content, mg / L 2102 1 4183 693 30912 70788

[0081] The ammonium chloride solution to be treated in the raw water tank 5 first enters the primary concentration system 3 for treatment, and the operating pressure during treatment is 8 MPa and the operating temperature is normal temperature; the primary concentrated water formed by the treatment enters the concentrated water tank 7, and the primary concentrated fresh water enters the secondary concentration system 4 through the intermediate water tank 8.

[0082] The water quality of the treated primary concentrated fresh water and primary concentrated water is shown in Table 7; the TDS of the primary concentrated fresh water is 72746.06 mg / L, and the TDS of the primary concentrated water is 133989.2 mg / L.

[0083] Table 7 Water quality of the primary concentrated fresh water and primary concentrated water

[0084]

[0085]

[0086] 2. Treatment by the secondary concentration system

[0087] The first-stage concentrated fresh water enters the second-stage concentration system 4 for treatment. The operating pressure during treatment is 7 MPa, and the operating temperature is normal temperature. The second-stage concentrated brine formed during treatment returns to the original water tank 5, and the second-stage concentrated fresh water enters the seawater desalination system 1.

[0088] The water quality of the treated second-stage concentrated fresh water and second-stage concentrated brine is shown in Table 8. The TDS of the second-stage concentrated fresh water is 40600.06 mg / L, and the TDS of the second-stage concentrated brine is 103960.06 mg / L.

[0089] Table 8 Water Quality of Second-Stage Concentrated Fresh Water and Second-Stage Concentrated Brine

[0090]

[0091] 3. Treatment by Seawater Desalination System

[0092] The second-stage concentrated fresh water enters the seawater desalination system 1 for treatment. The operating pressure during treatment is 6 MPa, and the operating temperature is normal temperature. The seawater desalination brine formed during treatment returns to the second-stage concentration system 4 through the intermediate water tank 8, and the seawater desalination fresh water enters the brackish water system 2.

[0093] The water quality of the treated seawater desalination fresh water and seawater desalination brine is shown in Table 9. The TDS of the seawater desalination fresh water is 2235.37 mg / L, and the TDS of the seawater desalination brine is 64746.47 mg / L.

[0094] Table 9 Water Quality of Seawater Desalination Fresh Water and Seawater Desalination Brine

[0095]

[0096]

[0097] 4. Treatment by Brackish Water System

[0098] The seawater desalination fresh water enters the brackish water system 2 for treatment. The operating pressure during treatment is 3 MPa, and the operating temperature is normal temperature. The brackish water brine formed during treatment returns to the seawater desalination system 1, and the brackish water fresh water enters the fresh water tank 6.

[0099] The water quality of the treated brackish water fresh water and brackish water brine is shown in Table 10. The TDS of the brackish water fresh water is 246.037 mg / L, and the TDS of the brackish water brine is 8149.17 mg / L.

[0100] Table 10 Water Quality of Brackish Water Fresh Water and Brackish Water Brine

[0101]

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for concentrating ammonium chloride solution and co-producing fresh water, characterized in that, It includes a fresh water system, a concentrated water system and a water storage system. The fresh water system includes a seawater desalination system and a brackish water system arranged in sequence. The concentrated water system includes a primary concentration system and a secondary concentration system arranged in sequence. The concentrated water system is connected to the fresh water system. The water storage system includes a raw water tank, a fresh water tank and a concentrated water tank. The raw water tank is connected to the fresh water system or the concentrated water system. The fresh water tank is connected to the brackish water system. The concentrated water tank is connected to the concentrated water system.

2. The system according to claim 1, wherein When the TDS of the ammonium chloride solution to be treated in the raw water tank ≤ 45000 mg / L, the raw water tank is connected to the fresh water system and the concentrated water system in sequence; when the TDS of the ammonium chloride solution to be treated in the raw water tank > 45000 mg / L, the raw water tank is connected to the concentrated water system and the fresh water system in sequence.

3. The system according to claim 1, wherein The raw water tank is connected to the seawater desalination system. The fresh water outlet of the seawater desalination system is connected to the brackish water system. The concentrated water outlet of the seawater desalination system is connected to the primary concentration system through an intermediate water tank. The fresh water outlet and the concentrated water outlet of the brackish water system are respectively connected to the fresh water tank and the seawater desalination system. The fresh water outlet and the concentrated water outlet of the primary concentration system are respectively connected to the raw water tank and the secondary concentration system. The fresh water outlet and the concentrated water outlet of the secondary concentration system are respectively connected to the intermediate water tank and the concentrated water tank.

4. The system according to claim 1, characterized in that, The raw water tank is connected to the primary concentration system. The concentrated water outlet of the primary concentration system is connected to the concentrated water tank. The fresh water outlet of the primary concentration system is connected to the secondary concentration system through an intermediate water tank. The fresh water outlet and the concentrated water outlet of the secondary concentration system are respectively connected to the seawater desalination system and the raw water tank. The fresh water outlet and the concentrated water outlet of the seawater desalination system are respectively connected to the brackish water system and the intermediate water tank. The fresh water outlet and the concentrated water outlet of the brackish water system are respectively connected to the fresh water tank and the seawater desalination system.

5. The system according to claim 1, wherein The TDS of the concentrated water discharged from the seawater desalination system ≥ 50000 mg / L, and the TDS of the fresh water discharged from the seawater desalination system ≤ 2300 mg / L.

6. The system according to claim 1, characterized in that The TDS of the concentrated water discharged from the brackish water system ≥ 5000 mg / L, and the TDS of the fresh water discharged from the brackish water system ≤ 300 mg / L.

7. The system according to claim 1, wherein The TDS of the concentrated water discharged from the primary concentration system ≥ 110000 mg / L, and the TDS of the fresh water discharged from the primary concentration system ≤ 73000 mg / L.

8. The system according to claim 3, wherein The TDS of the concentrated water discharged from the secondary concentration system ≥ 170000 mg / L, and the TDS of the fresh water discharged from the secondary concentration system ≤ 80000 mg / L.

9. A method for concentrating ammonium chloride solution and co-producing fresh water, characterized in that, The system described in any one of claims 1-8 is used to concentrate the ammonium chloride solution to be treated and produce fresh water in parallel.

10. The method according to claim 9, wherein The TDS of the ammonium chloride solution to be treated is 400 - 150000 mg / L; the TDS of the concentrated ammonium chloride solution ≥ 170000 mg / L, and the TDS of the fresh water ≤ 300 mg / L.

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