Liquid desalination system

Abstract

The utility model discloses a liquid desalination system, which belongs to the field of desalination treatment, and comprises a first water tank, a second water tank, a first circulating pump, a second circulating pump, a third circulating pump, a fourth circulating pump, an electrodialysis system and a pH regulator, a fresh water outlet of the electrodialysis system is communicated with the first water tank, the first water tank is communicated with one water inlet of the pH regulator through a third circulating pump, one water outlet of the pH regulator is communicated with the first water tank, and the second water tank is communicated with a concentrated water inlet of the electrodialysis system through a second circulating pump; a concentrated water outlet of the electrodialysis system is communicated with a second water tank, the second water tank is communicated with the other water inlet of the pH regulator through a fourth circulating pump, and the other water outlet of the pH regulator is communicated with the second water tank. According to the utility model, the pH value is adjusted in real time, so that the material loss is effectively reduced.

Description

Technical Field

[0001] This utility model belongs to the field of desalination treatment, and in particular relates to a liquid desalination system. Background Technology

[0002] In modern industrial production and numerous scientific research fields, liquid desalination is a crucial operational step. Currently, electrodialysis systems, as a commonly used desalination method, are widely applied in many industries such as water treatment, chemical raw material refining, and biopharmaceuticals. Its basic working principle is to utilize the selective permeability of ion exchange membranes to anions and cations, driven by an electric field, to separate salts from other components in the solution, thereby achieving the goal of desalination.

[0003] However, electrodialysis systems exhibit significant limitations when dealing with liquids possessing weak ionization properties. These weakly ionized liquids can only partially ionize into positive and negative ions in solution, and the degree of ionization is relatively low. For example, while electrodialysis can recover MDEA from MDEA-containing solutions through desalination, the weak ionization of MDEA causes the generated positive ions to migrate with the electric field, resulting in a high loss rate. Similarly, for the recovery of glycolic acid, pH adjustment is typically followed by desalination via an electrodialysis system. However, glycolic acid is weakly ionized, causing the generated glycolate anions to migrate with the electric field, resulting in a high loss rate. This not only increases the operating costs of the electrodialysis system but also necessitates frequent replacement of ion exchange membranes, reducing the continuity and stability of production. Utility Model Content

[0004] The purpose of this invention is to provide a liquid desalination system to overcome at least one of the above-mentioned defects in the prior art.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] This utility model provides a liquid desalination system, including a first water tank, a second water tank, a first circulating pump, a second circulating pump, a third circulating pump, a fourth circulating pump, an electrodialysis system, and a pH regulator. The first water tank is connected to the freshwater inlet of the electrodialysis system via the first circulating pump, and the freshwater outlet of the electrodialysis system is connected to the first water tank. The pH regulator has two inlets and two outlets. The first water tank is connected to one of the inlets of the pH regulator via the third circulating pump, and one of the outlets of the pH regulator is connected to the first water tank. The second water tank is connected to the concentrate inlet of the electrodialysis system via the second circulating pump, and the concentrate outlet of the electrodialysis system is connected to the second water tank. The second water tank is connected to the other inlet of the pH regulator via the fourth circulating pump, and the other outlet of the pH regulator is connected to the second water tank.

[0007] Preferably, it also includes a pH detector, the detection end of which extends into the first water tank.

[0008] Preferably, the pH regulator includes a housing, and a first pH adjustment section and a second pH adjustment section disposed in the housing. The outlet of the third circulation pump is connected to the inlet of the first pH adjustment section through a pipe, the outlet of the first pH adjustment section is connected to the first water tank through a pipe, the outlet of the fourth circulation pump is connected to the inlet of the second pH adjustment section through a pipe, and the outlet of the second pH adjustment section is connected to the second water tank through a pipe.

[0009] Preferably, the system also includes a third water tank and a fifth circulating pump. The third water tank is connected to the electrode liquid inlet of the electrodialysis system via the fifth circulating pump, and the electrode liquid outlet of the electrodialysis system is connected to the third water tank.

[0010] Preferably, the current density of the electrodialysis system is 50-4000 A / m 2 .

[0011] The beneficial effects of this utility model are as follows:

[0012] 1. By adjusting the pH value in real time through a pH regulator, positive ionization is suppressed. During the electrodialysis process, the liquid to be recovered remains in a molecular state and will not migrate with the electric field, thus reducing material loss.

[0013] 2. By setting up a pH probe, the pH of the liquid in the first water tank is monitored in real time, and combined with a pH regulator, precise online real-time pH adjustment is achieved. Attached Figure Description

[0014] Figure 1 This is a system block diagram of Embodiment 1 of the present invention.

[0015] Figure 2 This is a schematic diagram of the structure of the first water tank and pH detector in Embodiment 1 of this utility model.

[0016] Figure 3 This is a schematic diagram of the pH regulator in Embodiment 1 of this utility model.

[0017] The labels in the attached diagram are as follows: 1-First water tank, 2-Second water tank, 3-First circulation pump, 4-Second circulation pump, 5-Third circulation pump, 6-Fourth circulation pump, 7-Electrodialysis system, 8-pH regulator, 9-pH detector, 81-Shell, 82-First pH adjustment section, 83-Second pH adjustment section, 10-Third water tank, 11-Fifth circulation pump. Detailed Implementation

[0018] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0019] Contents not described in detail in this specification are existing technologies known to those skilled in the art. In the description of this utility model, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this utility model. Furthermore, terms such as "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0020] Example 1:

[0021] like Figures 1 to 3As shown, the liquid desalination system provided in this embodiment includes a first water tank 1, a second water tank 2, a first circulation pump 3, a second circulation pump 4, a third circulation pump 5, a fourth circulation pump 6, an electrodialysis system 7, and a pH regulator 8. The first water tank 1 is connected to the freshwater inlet of the electrodialysis system 7 via the first circulation pump 3, and the freshwater outlet of the electrodialysis system 7 is connected to the first water tank 1. The pH regulator 8 has two inlets and two outlets. The first water tank 1 is connected to one of the inlets of the pH regulator 8 via the third circulation pump 5, and one of the outlets of the pH regulator 8 is connected to the first water tank 1. The second water tank 2 is connected to the concentrate inlet of the electrodialysis system 7 via the second circulation pump 4, and the concentrate outlet of the electrodialysis system 7 is connected to the second water tank 2. The second water tank 2 is connected to the other inlet of the pH regulator 8 via the fourth circulation pump 6, and the other outlet of the pH regulator 8 is connected to the second water tank 2. The liquid is desalinated using electrodialysis system 7. The desalinated freshwater is returned to the first tank 1 and circulated by the first circulation pump 3 until the required level is reached. Then, the circulation is stopped, and the freshwater is collected from the first tank 1. Similarly, the concentrated water from the desalination process is returned to the second tank 2 and circulated by the second circulation pump 4 until the required level is reached. Then, the circulation is stopped, and the concentrated water is collected from the second tank 2. Because the return of freshwater and concentrated water causes changes in the pH value of the liquid in the first and second tanks 2, the electrodialysis system 7 is shut down when the pH value deviates from a certain range. The pH value in the first and second tanks 2 is adjusted to the required value using pH regulator 8, and then the electrodialysis system 7 is restarted. This process is repeated until the treatment is complete. Real-time pH adjustment by pH regulator 8 suppresses positive ionization. During the electrodialysis process, the liquid to be recovered remains in a molecular state and does not migrate with the electric field, reducing material loss.

[0022] This also includes a pH sensor 9, whose probe extends into the first water tank 1. The pH sensor 9 is used to monitor the pH of the liquid in the first water tank 1 in real time, and in conjunction with the pH regulator 8, enables precise online real-time pH adjustment.

[0023] The pH regulator 8 includes a housing 81, and a first pH adjustment section 82 and a second pH adjustment section 83 disposed on the housing 81. The outlet of the third circulation pump 5 is connected to the inlet of the first pH adjustment section 82 via a pipe, and the outlet of the first pH adjustment section 82 is connected to the first water tank 1 via a pipe. The outlet of the fourth circulation pump 6 is connected to the inlet of the second pH adjustment section 83 via a pipe, and the outlet of the second pH adjustment section 83 is connected to the second water tank 2 via a pipe. The pH of the liquid entering the regulator is adjusted by the first pH adjustment section 82 and the second pH adjustment section 83, and the liquid is then returned to the first water tank 1 and the second water tank 2, respectively.

[0024] This system also includes a third water tank 10 and a fifth circulation pump 11. The third water tank 10 is connected to the electrode solution inlet of the electrodialysis system 7 via the fifth circulation pump 11, and the electrode solution outlet of the electrodialysis system 7 is connected to the third water tank 10. The arrangement of the third water tank 10 and the fifth circulation pump 11 enables the recycling of the electrode solution, reducing the amount of electrode solution used and making it more environmentally friendly.

[0025] Among them, the current density of electrodialysis system 7 is 50-4000 A / m. 2 Different current densities can be selected based on the different treatment solutions to achieve better treatment results.

[0026] This example uses the recycling of MDEA:

[0027] 1. Add MDEA-containing solution to the first water tank 1, add pure water to the second water tank 2, and add electrode solution to the third water tank 10.

[0028] 2. Turn on the first circulation pump 3, the second circulation pump 4, and the fifth circulation pump 11, and adjust the flow rate to maintain consistent pressure in each pipeline. Turn on the electrodialysis system 7 and set the corresponding parameters.

[0029] 3. After the system starts operating, the fresh water produced by the electrodialysis system 7 is returned to the first water tank 1 and circulated through the electrodialysis system 7 for further treatment, causing the pH of the liquid in the first water tank 1 to gradually decrease. The concentrated water produced by the electrodialysis system 7 is returned to the second water tank 2 and circulated through the electrodialysis system 7 for further treatment, causing the concentration of the liquid in the second water tank 2 to gradually increase. When the pH of the feed solution drops below 11, the first circulation pump 3, the second circulation pump 4, the fifth circulation pump 11, and the electrodialysis system 7 are shut down.

[0030] 4. Turn on the third circulation pump 5 and the fourth circulation pump 6, and adjust the flow rate to maintain consistent pressure in each pipeline. Turn on the pH regulator 8 and set the corresponding parameters.

[0031] 5. When the pH of the liquid in the first water tank 1 rises above 11, turn off the pH regulator 8 and continue operation as described in steps 2 and 3.

[0032] 6. Repeat this process until the heat-stable salts in the MDEA-containing solution are removed to the required standard.

[0033] In this way, the positive ionization of MDEA is suppressed, reducing the generation of positive ions. During electrodialysis, MDEA remains in a molecular state and will not migrate with the electric field, thus reducing MDEA loss. After conventional electrodialysis, the loss rate of the active ingredient MDEA is approximately 15%. Using the liquid desalination system of this invention, the MDEA loss rate can be reduced to approximately 5%.

[0034] Example 2:

[0035] The difference between this embodiment and Embodiment 1 is that:

[0036] This example uses the recovery of glycolic acid:

[0037] 1. Add glycolic acid solution to the first water tank 1, add pure water to the second water tank 2, and add electrode solution to the third water tank 10.

[0038] 2. Turn on the first circulation pump 3, the second circulation pump 4, and the fifth circulation pump 11, and adjust the flow rate to maintain consistent pressure in each pipeline. Turn on the electrodialysis system 7 and set the corresponding parameters.

[0039] 3. After the system starts operating, the fresh water produced by the electrodialysis system 7 is returned to the first water tank 1 and circulated through the electrodialysis system 7 for further treatment, causing the pH of the liquid in the first water tank 1 to gradually increase. The concentrated water produced by the electrodialysis system 7 is returned to the second water tank 2 and circulated through the electrodialysis system 7 for further treatment, causing the concentration of the liquid in the second water tank 2 to gradually increase. When the pH of the feed solution rises above 2, the first circulation pump 3, the second circulation pump 4, the fifth circulation pump 11, and the electrodialysis system 7 are shut down.

[0040] 4. Turn on the third circulation pump 5 and the fourth circulation pump 6, and adjust the flow rate to maintain consistent pressure in each pipeline. Turn on the pH regulator 8 and set the corresponding parameters.

[0041] 5. When the pH of the liquid in the first water tank 1 drops below 2, turn off the pH regulator 8 and continue operation as described in steps 2 and 3.

[0042] 6. Repeat this process until the sodium glycolate in the glycolic acid-containing solution is removed to the required standard.

[0043] Thus, by controlling the pH at a lower level through pH regulator 8, the positive ionization of glycolic acid is suppressed, reducing the generation of negative ions. During subsequent electrodialysis, glycolic acid exists in molecular form and will not migrate with the electric field, reducing material loss. When the glycolic acid-containing solution is adjusted to pH and then directly processed through a conventional electrodialysis system 7, the material loss rate is approximately 10%. Using the liquid desalination system of this invention, the loss rate can be reduced to approximately 3%.

[0044] The control method of this utility model is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the field. Since this utility model is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail.

[0045] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1.A liquid desalination system, comprising: a first water tank, a second water tank, a first circulating pump, a second circulating pump, a third circulating pump, a fourth circulating pump, an electrodialysis system, and a pH regulator; the first water tank is connected to a fresh water inlet of the electrodialysis system through the first circulating pump, and a fresh water outlet of the electrodialysis system is connected to the first water tank; the pH regulator has two inlets and two outlets; the first water tank is connected to one of the inlets of the pH regulator through the third circulating pump, and one of the outlets of the pH regulator is connected to the first water tank; the second water tank is connected to a concentrated water inlet of the electrodialysis system through the second circulating pump, and a concentrated water outlet of the electrodialysis system is connected to the second water tank; the second water tank is connected to the other inlet of the pH regulator through the fourth circulating pump, and the other outlet of the pH regulator is connected to the second water tank. 2.The liquid desalination system of claim 1, further comprising a pH detector, wherein a detection end of the pH detector extends into the first water tank. 3.The liquid desalination system of claim 2, wherein the pH regulator comprises a housing, and a first pH regulating section and a second pH regulating section arranged in the housing; an outlet of the third circulating pump is connected to an inlet of the first pH regulating section through a pipe, and an outlet of the first pH regulating section is connected to the first water tank through a pipe; an outlet of the fourth circulating pump is connected to an inlet of the second pH regulating section through a pipe, and an outlet of the second pH regulating section is connected to the second water tank through a pipe. 4.The liquid desalination system of claim 3, further comprising a third water tank and a fifth circulating pump, wherein the third water tank is connected to an electrolyte inlet of the electrodialysis system through the fifth circulating pump, and an electrolyte outlet of the electrodialysis system is connected to the third water tank. 5.The liquid desalination system of claim 1, wherein the first water tank, the second water tank, the first circulating pump, the second circulating pump, the third circulating pump, the fourth circulating pump, the electrodialysis system, and the pH regulator are arranged in a same housing. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The current density of the electrodialysis system is 50-4000 A / m 2 .

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