Carbon dioxide brine refining device

Abstract

The utility model belongs to the technical field of brine refining, and relates to a carbon dioxide brine refining device which comprises a settling unit, a gas-liquid mixer, a pressurized dissolved gas reaction tank and a carbon dioxide buffer tank, the settling unit, the gas-liquid mixer and the pressurized gas dissolving reaction tank are communicated in sequence; the gas-liquid mixer is also communicated with a carbon dioxide buffer tank; the gas-liquid mixer comprises a shell, a liquid spray pipe and a gas suction pipe; a cavity is formed in the shell, and the settling unit is communicated with the pressurized gas dissolving reaction tank through the liquid spraying pipe and the cavity; and the carbon dioxide buffer tank is communicated with the cavity through an air suction pipe. According to the utility model, the gas-liquid mixer is arranged between the settling unit and the pressurized dissolved gas reaction tank, and carbon dioxide is introduced into the gas-liquid mixer through the carbon dioxide buffer tank, so that the carbon dioxide is fully mixed with saline water treated by the settling unit, and the treatment effect is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of brine refining and relates to a carbon dioxide brine refining device. Background Art

[0002] The chlor-alkali industry has entered a stable growth stage with structural adjustment and efficiency improvement as the main features. Against the backdrop of stricter energy conservation, tighter emission reduction and high pressure on environmental protection, the chlor-alkali industry must get rid of the growth mode that simply pursues scale expansion, further curb the inefficient and disorderly development of the industry and improve the quality of industry growth. In addition, the chlor-alkali industry will also focus on adjusting and optimizing the industrial structure, including raw material structure, technical structure and product structure, and gradually resolve long-term accumulated structural contradictions and resource and environmental protection constraints.

[0003] In the chlor-alkali industry, solid sodium chloride is dissolved in water to reach a saturated state, and then various additives are added to the brine to remove harmful impurities to meet the quality requirements of brine for diaphragm caustic soda production. Such brine is collectively referred to as primary brine. The purpose of primary brine refining is to remove impurities such as calcium, magnesium, sulfate, organic matter, and precipitable matter in the crude brine to ensure the normal operation of the subsequent electrolysis process.

[0004] At present, the traditional method of primary brine refining generally adopts brine pretreatment. The treatment process of this primary brine is relatively stable, easy for ordinary operators to master, and easy to operate, but the suspended matter content in the primary brine is relatively high, which increases the processing pressure of the subsequent process; the adaptability to salt quality changes (especially high magnesium salt) is poor. The Chinese patent document with the announcement number CN216418848U discloses a carbon dioxide gas recovery and utilization device, including a scrubber, a brine mixing tank assembly and a filter; the input end of the scrubber is connected to a carbon dioxide gas input pipeline, and the output end of the scrubber is connected to the input end of the brine mixing tank assembly, so that the carbon dioxide gas enters the brine mixing tank assembly after passing through the scrubber for precipitation reaction treatment; the carbon dioxide gas in the carbon dioxide gas is used in the primary brine refining process in the chlor-alkali enterprise to reduce the carbon dioxide emission of the enterprise, but in the prior art, the input end of the scrubber is directly connected to the carbon dioxide gas input pipeline, and the carbon dioxide gas is unevenly mixed with the liquid brine, resulting in poor treatment effect. Utility Model Content

[0005] In order to solve the technical problem that the input end of the existing scrubber is directly connected to the carbon dioxide gas input pipeline, the carbon dioxide gas and the liquid brine are unevenly mixed, resulting in poor treatment effect, the utility model provides a carbon dioxide brine refining device.

[0006] The utility model arranges a gas-liquid mixer between the sedimentation unit and the pressurized dissolved gas reaction tank, and simultaneously introduces carbon dioxide into the gas-liquid mixer through a carbon dioxide buffer tank, so that the carbon dioxide and the brine treated by the sedimentation unit are fully mixed, thereby improving the treatment effect.

[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0008] A carbon dioxide brine refining device comprises a sedimentation unit, a gas-liquid mixer, a pressurized gas-dissolving reaction tank and a carbon dioxide buffer tank; the sedimentation unit, the gas-liquid mixer and the pressurized gas-dissolving reaction tank are connected in sequence; the gas-liquid mixer is also connected to the carbon dioxide buffer tank.

[0009] It is further defined that the gas-liquid mixer includes a shell, a liquid nozzle and an air intake pipe; a cavity is arranged inside the shell, and the sedimentation unit is connected to the pressurized dissolved gas reaction tank via the liquid nozzle and the cavity; the carbon dioxide buffer tank is connected to the cavity via the air intake pipe.

[0010] It is further defined that the cavity is arranged along the axial direction of the shell; the axial direction of the liquid nozzle is the same as the axial direction of the shell; and the axial direction of the air intake pipe is perpendicular to the axial direction of the shell.

[0011] It is further defined that the liquid nozzle includes a straight pipe section and a convergent section connected to the straight pipe section, the straight pipe section is located outside the shell, the convergent section is located in the cavity, and the air intake pipe is located above the side wall of the convergent section. The sedimentation unit is connected to the straight pipe section.

[0012] It is further defined that the cavity is a Venturi structure.

[0013] It is further defined that the cavity is composed of a suction section, a throat section and a diffusion section which are connected in sequence; the suction section continuously and gradually shrinks toward the throat section along the axial direction of the cavity, the diffusion section extends and diffuses from the throat section connection to the outside of the shell, the convergence section of the liquid nozzle is placed in the suction section, and the diffusion section is connected to the pressurized dissolved air reaction tank.

[0014] It is further defined that the sedimentation unit includes a first sedimentation tank, a second sedimentation tank and a second sodium hydroxide pipeline; the first sedimentation tank is connected to the liquid nozzle through the second sedimentation tank; the second sodium hydroxide pipeline is placed between the first sedimentation tank and the second sedimentation tank and is connected to the first sedimentation tank and the second sedimentation tank respectively.

[0015] It is further defined that the carbon dioxide brine refining device also includes a batching tank and a sodium hypochlorite pipeline and a first sodium hydroxide pipeline respectively connected to the inside of the batching tank, and the batching tank is also connected to the first sedimentation tank.

[0016] It is further defined that the carbon dioxide brine refining device also includes a buffer tank and a filter which are connected in sequence; the buffer tank is also connected to the pressurized dissolved gas reaction tank.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] 1. The utility model sets a gas-liquid mixer between the sedimentation unit and the pressurized dissolved gas reaction tank, and introduces carbon dioxide into the gas-liquid mixer through the carbon dioxide buffer tank, so that the carbon dioxide and the alkaline brine treated by the sedimentation unit are fully mixed, thereby improving the treatment effect.

[0019] 2. In the utility model, the gas-liquid mixer includes a shell, a liquid nozzle and an air intake pipe; a cavity is arranged inside the shell, and the sedimentation unit is connected to the pressurized dissolved gas reaction tank through the liquid nozzle and the cavity; the carbon dioxide buffer tank is connected to the cavity through the air intake pipe. The cavity is arranged along the axial direction of the shell; the axial direction of the liquid nozzle is the same as the axial direction of the shell; the axial direction of the air intake pipe is perpendicular to the axial direction of the shell. The liquid flow enters the shell from the axial direction, and the gas flow enters from the tangential direction, so that the gas-liquid mixing is more complete.

[0020] 3. In the utility model, by setting a second sodium hydroxide pipeline, sodium hydroxide is added to the brine to be treated after the first sedimentation tank to adjust the pH of the brine so that the pH is within the range of 11 to 13, creating conditions for the subsequent mixing of brine and carbon dioxide to precipitate calcium ions. The structure is simple and is conducive to the operation of the subsequent mixed gas reaction.

[0021] 4. In the utility model, a buffer tank and a filter are provided to filter the brine after the carbon dioxide is precipitated, so as to ensure that the total amount of calcium and magnesium in the final brine meets the subsequent use requirements and the refining effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the brine carbonization refining device provided by the utility model;

[0023] Figure 2 A cross-sectional view of the gas-liquid mixer provided by the utility model;

[0024] In the figure:

[0025] 1-dosing tank, 2-first sedimentation tank, 3-second sedimentation tank, 4-gas-liquid mixer, 401-shell, 402-intake pipe, 403-liquid nozzle, 404-intake section, 405-throat section, 406-diffusion section, 5-pressurized dissolved gas reaction tank, 6-buffer tank, 7-filter, 8-carbon dioxide buffer tank, 9-brine delivery pump, 10-buffer tank delivery pump, 11-filter feed pump, 12-sodium hypochlorite pipeline, 13-first sodium hydroxide pipeline, 14-second sodium hydroxide pipeline. DETAILED DESCRIPTION

[0026] The technical solution protected by the utility model is now described in detail in conjunction with the accompanying drawings and embodiments. However, it is obvious that the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0027] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and other similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] Example 1

[0029] See also Figure 1 The carbon dioxide brine refining device provided in this embodiment includes a sedimentation unit, a gas-liquid mixer 4, a pressurized dissolved gas reaction tank 5 and a carbon dioxide buffer tank 8; the sedimentation unit, the gas-liquid mixer 4 and the pressurized dissolved gas reaction tank 5 are connected in sequence; the gas-liquid mixer 4 is also connected to the carbon dioxide buffer tank 8.

[0030] In this embodiment, the sedimentation unit is used to precipitate magnesium ions in the salt water.

[0031] See also Figure 2 The gas-liquid mixer 4 includes a shell 401, a liquid nozzle 403 and an air intake pipe 402; a cavity is arranged inside the shell 401, and the sedimentation unit is connected with the pressurized dissolved gas reaction tank 5 through the liquid nozzle 403 and the cavity; the carbon dioxide buffer tank 8 is connected with the cavity through the air intake pipe 402.

[0032] Specifically, the shell 401 is a cylindrical tube structure, a cavity is opened in the axial direction of the shell 401, and the cavity is arranged along the axial direction of the shell 401; the axial direction of the liquid nozzle 403 is the same as the axial direction of the shell 401; the axial direction of the intake pipe 402 is perpendicular to the axial direction of the shell 401.

[0033] In practice, the liquid nozzle 403 includes a straight pipe section and a convergent section connected to the straight pipe section, the straight pipe section is located outside the housing 401, the convergent section is located in the cavity, and the air intake pipe 402 is located above the side wall of the convergent section. The straight pipe section is connected to the sedimentation unit.

[0034] In this embodiment, the cavity is a Venturi structure.

[0035] Specifically, the cavity is composed of a suction section 404, a throat section 405 and a diffusion section 406 which are connected in sequence; the liquid nozzle 403 is placed in the suction section 404, and the convergent section of the liquid nozzle 403 extends into one end of the suction section 404, and the outer diameter of the liquid nozzle 403 is smaller than the radial width of the suction section 404, and the other end of the suction section 404 continuously shrinks toward the throat section 405, and the diffusion section 406 extends and diffuses from the connection of the throat section 405 to the outside of the shell 401, and finally the diffusion section 406 is connected to the upper side wall of the pressurized dissolved gas reaction tank 5.

[0036] Example 2

[0037] See also Figure 1 On the basis of Example 1, the carbon dioxide brine refining device provided in this embodiment comprises a sedimentation unit including a first sedimentation tank 2, a second sedimentation tank 3 and a second sodium hydroxide pipeline 14; the first sedimentation tank 2 is connected to the liquid nozzle 403 via the second sedimentation tank 3; the second sodium hydroxide pipeline 14 is placed between the first sedimentation tank 2 and the second sedimentation tank 3 and is connected to the first sedimentation tank 2 and the second sedimentation tank 3 respectively.

[0038] The carbon dioxide brine refining device provided in this embodiment also includes a batching tank 1 and a sodium hypochlorite pipeline 12 and a first sodium hydroxide pipeline 13 respectively connected to the inside of the batching tank 1. The batching tank 1 is also connected to the first sedimentation tank 2.

[0039] Specifically, the batching tank 1 is a rectangular tank structure, and the top opening is respectively connected to a sodium hypochlorite pipeline 12 and a first sodium hydroxide pipeline 13; a water inlet is arranged on the left wall of the batching tank 1, and a water outlet is arranged on the right wall of the batching tank 1. Both the water inlet and the water outlet are connected to pipelines, the water inlet is used to pass the salt water to be treated into the batching tank 1, and the water outlet is used to discharge the salt water to be treated with the reagents (sodium hypochlorite and sodium hydroxide) from the batching tank 1 and enter the first sedimentation tank 2.

[0040] Specifically, the first sedimentation tank 2 and the second sedimentation tank 3 are connected through a delivery pipeline to realize the delivery of the brine to be treated; the second sodium hydroxide pipeline 14 is connected to the delivery pipeline, and sodium hydroxide reagent is added to the brine to be treated to adjust the pH of the brine to be treated.

[0041] During implementation, in order to speed up the reaction, stirring devices are installed in the first sedimentation tank 2 and the second sedimentation tank 3.

[0042] In this embodiment, the brine to be treated with sodium hypochlorite and sodium hydroxide is transported to the first sedimentation tank 2, stirred and fully reacted in the first sedimentation tank 2, and the reaction time is controlled to be 1h to 1.5h. After the reaction, the precipitation rate of magnesium ions reaches 94%, ensuring the full reaction of magnesium ions and organic impurities; the brine after the reaction is transported to the second sedimentation tank 3. Since the second sodium hydroxide pipeline 14 is connected to the pipeline between the first sedimentation tank 2 and the second sedimentation tank 3, the pH of the brine is adjusted to 11 to 13 by adding sodium hydroxide. The brine after the pH is adjusted is stirred in the second sedimentation tank 3 to make the solution more evenly mixed, so as to obtain a brine mixed solution with adjusted pH, which is transported into the gas-liquid mixer 4 by the brine delivery pump 9 and mixed evenly with carbon dioxide.

[0043] Example 3

[0044] See also Figure 1 On the basis of Example 1, the carbon dioxide brine refining device provided in this example further includes a buffer tank 6 and a filter 7 which are connected in sequence; the buffer tank 6 is also connected to the pressurized dissolved gas reaction tank 5.

[0045] Specifically, a water outlet is provided on the lower side wall of the pressurized dissolved gas reaction tank 5 , and the water outlet is communicated with the buffer tank 6 .

[0046] In this embodiment, a stirring device is installed in the buffer tank 6 to achieve stirring, ensure uniform mixing, and promote the reaction.

[0047] In this embodiment, the main purpose of the filter 7 is to filter the salt water. The filter 7 can be a membrane filter or other filters; preferably, the filter 7 is a membrane filter.

[0048] In this embodiment, the treated brine coming out from the lower part of the side of the pressurized dissolved gas reactor 5 is transported to the buffer tank 6 through the buffer tank delivery pump 10, mixed evenly under the stirring action, and then transported to the filter 7 by the filter feed pump 11. After membrane filtration, refined brine that meets subsequent requirements is obtained.

[0049] The brine carbonization refining device provided by the utility model has the following working process:

[0050] (1) After the brine to be treated at a temperature of 50°C to 65°C is transported to the batching tank 1, sodium hypochlorite and sodium hydroxide are added in sequence, and the corresponding sodium hypochlorite and sodium hydroxide are added according to the brine to be treated to complete the mixing and batching.

[0051] (2) The brine to be treated containing sodium hypochlorite and sodium hydroxide is transported to the first sedimentation tank 2, in which the sodium hypochlorite is fully stirred to remove ammonia and organic impurities such as bacteria and algae in the brine, and the sodium hydroxide is stirred to remove Mg in the brine. 2+ The reaction generates Mg(OH) 2After 1h to 1.5h of reaction, the precipitation rate of magnesium ions reaches 94%, completing the preliminary refining of the brine.

[0052] (3) The brine to be treated after the magnesium precipitation reaction is continuously transported, and sodium hydroxide is added thereto through the second sodium hydroxide pipeline 14 and then transported to the second sedimentation tank 3, where the solution is stirred to make it more evenly mixed, and the magnesium ions are further precipitated; at the same time, the pH of the brine to be treated is adjusted to 11-13.

[0053] (4) The pH-adjusted brine to be treated is delivered to the suction section 404 in the gas-liquid mixer 4 through the brine delivery pump 9 and the liquid nozzle 403. The carbon dioxide gas in the carbon dioxide buffer tank 8 is sucked into the suction section 404 in the gas-liquid mixer 4 through the suction pipe 402 under the Venturi structure in the gas-liquid mixer 4. The pH-adjusted brine to be treated and the carbon dioxide gas are fully mixed in the suction section 404. The mixed brine to be treated containing carbon dioxide gas is further mixed evenly under the action of the throat section 405, and the velocity gradient of the laminar flow of the fluid is increased. The gas-liquid mixture is sprayed into the pressurized dissolved gas reaction tank 5 through the diffusion section 406 in the form of turbulent flow, thereby increasing the contact area between the carbon dioxide and the brine, thereby making the reaction more complete. In the pressurized dissolved gas reaction tank 5, the calcium ions in the brine to be treated react fully and quickly with the carbon dioxide gas under alkaline conditions to produce calcium carbonate precipitation. The reaction pressure in the pressurized dissolved gas reaction tank 5 is 0.3Mpa-0.7Mpa, the reaction time is 0.5h, and the precipitation rate of calcium ions after the reaction reaches 99%.

[0054] (5) The treated brine after the reaction in the pressurized dissolved gas reactor 5 enters the buffer tank 6 through the buffer tank delivery pump 10, and is further stirred for reaction. At the same time, a small amount of carbon dioxide that has not been completely reacted is discharged. After that, the treated brine is delivered to the filter 7 through the filter feed pump 11 for filtration treatment. The total amount of calcium and magnesium in the treated brine is ≤1.5 mg / L, and the carbonized and refined brine meets the subsequent use requirements.

[0055] It should be noted that the sodium hydroxide in the first sodium hydroxide pipeline 13 and the second sodium hydroxide pipeline 14 are both from the sodium hydroxide product of the caustic soda section in the chlor-alkali production. When in use, the first sodium hydroxide pipeline 13 and the second sodium hydroxide pipeline 14 are both connected to the sodium hydroxide product storage bin of the caustic soda section. The carbon dioxide in the carbon dioxide buffer tank 8 comes from the carbon dioxide gas generated in the chlor-alkali production. In the utility model, the carbon dioxide and sodium hydroxide raw materials do not need to be purchased from outside, which reduces costs and reduces carbon emissions.

[0056] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only the specific implementation method of the utility model and is not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A carbon dioxide brine refining device, characterized in that: It comprises a sedimentation unit, a gas-liquid mixer (4), a pressurized gas-dissolving reaction tank (5) and a carbon dioxide buffer tank (8); the sedimentation unit, the gas-liquid mixer (4) and the pressurized gas-dissolving reaction tank (5) are connected in sequence; the gas-liquid mixer (4) is also connected to the carbon dioxide buffer tank (8).

2. The carbon dioxide brine refining device according to claim 1, characterized in that: The gas-liquid mixer (4) comprises a shell (401), a liquid nozzle (403) and an air intake pipe (402); a cavity is arranged inside the shell (401), and the sedimentation unit is connected to the pressurized dissolved gas reaction tank (5) via the liquid nozzle (403) and the cavity; the carbon dioxide buffer tank (8) is connected to the cavity via the air intake pipe (402).

3. The carbon dioxide brine refining device according to claim 2, characterized in that: The cavity is arranged along the axial direction of the shell (401); the axial direction of the liquid nozzle (403) is the same as the axial direction of the shell (401); and the axial direction of the air intake pipe (402) is perpendicular to the axial direction of the shell (401).

4. The carbon dioxide brine refining device according to claim 3, characterized in that: The liquid nozzle (403) comprises a straight pipe section and a convergent section connected to the straight pipe section, the straight pipe section is located outside the shell (401), the convergent section is located in the cavity, and the air intake pipe (402) is located above the side wall of the convergent section; the sedimentation unit is connected to the straight pipe section.

5. The carbon dioxide brine refining device according to claim 4, characterized in that: The cavity is a Venturi structure.

6. The carbon dioxide brine refining device according to claim 4, characterized in that: The cavity is composed of a suction section (404), a throat section (405) and a diffusion section (406) which are connected in sequence; the suction section (404) gradually shrinks toward the throat section (405) along the axial direction of the cavity, and the diffusion section (406) extends from the connection point of the throat section (405) to the outside of the shell (401) and diffuses; the convergent section of the liquid nozzle (403) is placed in the suction section (404), and the diffusion section (406) is connected to the pressurized dissolved gas reaction tank (5).

7. The carbon dioxide brine refining device according to claim 5 or 6, characterized in that: The sedimentation unit comprises a first sedimentation tank (2), a second sedimentation tank (3) and a second sodium hydroxide pipeline (14); the first sedimentation tank (2) is connected to a liquid nozzle (403) via the second sedimentation tank (3); the second sodium hydroxide pipeline (14) is placed between the first sedimentation tank (2) and the second sedimentation tank (3), and is respectively connected to the first sedimentation tank (2) and the second sedimentation tank (3).

8. The carbon dioxide brine refining device according to claim 7, characterized in that: The carbon dioxide brine refining device further comprises a batching tank (1) and a sodium hypochlorite pipeline (12) and a first sodium hydroxide pipeline (13) respectively connected to the inside of the batching tank (1); the batching tank (1) is also connected to the first sedimentation tank (2).

9. The carbon dioxide brine refining device according to claim 8, characterized in that: The carbon dioxide brine refining device further comprises a buffer tank (6) and a filter (7) which are connected in sequence; the buffer tank (6) is also connected to the pressurized dissolved gas reaction tank (5).

Images