Device and method for removing carbonate radicals in wastewater

Abstract

The invention discloses a device and a method for removing carbonate in wastewater. The device comprises a baffling mixer, a buffer unit and a unit for removing acid gas which are sequentially connected in series, the baffling mixer comprises a mixer body and a plurality of baffling assemblies, and the multiple baffling assemblies are arranged in the mixer body in a staggered mode to form a snakelike circulation channel. Acid and alkaline wastewater containing carbonate ions / bicarbonate ions are uniformly mixed through the baffling mixer, and a gas space is reserved at the upper part of the mixer, so that carbon dioxide gas generated in the neutralization process can be simultaneously released in the baffling mixer and the buffer tank to keep the low pressure of the equipment, and the energy consumption is reduced. Therefore, the technical problem that a traditional mixer cannot be applied to the working condition that a large amount of gas is generated in the mixing process is solved. The wastewater treatment device disclosed by the invention not only can effectively remove carbonate radicals in alkaline wastewater and treat wastes with wastes, but also avoids the problem that liquid mixed with a large amount of bubbles cannot be conveyed by a traditional centrifugal pump.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical wastewater treatment, and in particular relates to a device and method for removing carbonate ions in wastewater. Background Art

[0002] The alkaline wastewater from the chemical gas absorption device contains a large amount of carbonate. When it is sent to sewage treatment or other recovery devices, it is easy to precipitate with calcium, magnesium and other ions, which will cause problems for the transportation and treatment facilities.

[0003] Currently, alkaline wastewater is mostly treated by neutralization, which first requires solving the problem of uniform mixing. Secondly, the carbonate neutralization reaction produces a large number of carbon dioxide bubbles. Traditional acid-base neutralization mixing equipment includes pipeline mixers, mixing tanks with agitation, or acid washing towers. However, when using a mixing tank with agitation to treat alkaline wastewater, additional stirring facilities and electricity consumption are required; using an acid washing tower to treat alkaline wastewater requires a large amount of equipment, which not only increases the floor space but also increases electricity consumption. With traditional pipeline mixers, the generation of large amounts of carbon dioxide bubbles after the carbonate neutralization reaction may also cause problems such as pipeline vibration and air blockage. Summary of the Invention

[0004] In order to improve the above technical problems, the present invention provides a device and method for removing carbonate ions from wastewater. Acid and alkaline wastewater containing carbonate ions / bicarbonate ions are uniformly mixed by a baffle mixer to produce an acid-base neutralization reaction. The neutralizing liquid in the baffle mixer flows from a high place to a lower buffer tank, and a gas space is retained in the upper part of the mixer. Therefore, the carbon dioxide gas generated during the neutralization process can be released simultaneously in the baffle mixer and the buffer tank to maintain low pressure of the equipment and reduce equipment requirements, thereby solving the technical problem that a large amount of gas is generated during the mixing process of the traditional mixer; the carbon dioxide gas generated by neutralization is released after being washed with water to remove the acid (HCl) gas, and the neutralized wastewater can be sent to a sewage treatment device or other deep treatment device for recycling according to the final brine concentration, pH value and organic matter content. The wastewater treatment device of the present invention can not only effectively remove carbonate ions in alkaline wastewater, treating waste with waste, but also avoids the problem that liquids mixed with a large number of bubbles cannot be transported by traditional centrifugal pumps.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0006] The invention provides a device for removing carbonate radicals in wastewater, comprising a baffle mixer, a buffer unit and a unit for removing acid gas which are connected in series in sequence.

[0007] According to an embodiment of the present invention, the baffle mixer includes: a mixer body and a plurality of baffle components, wherein the plurality of baffle components are staggeredly arranged inside the mixer body to form a serpentine flow channel inside the mixer body.

[0008] Multiple baffle components are located on different planes. The mixed liquid coming from upstream will contact and collide with each baffle component, so that the mixed liquid can be collided multiple times, thereby making the mixed liquid more evenly and fully mixed, and making the neutralization reaction between the acid and the carbonate ion / bicarbonate ion more thorough, thereby improving the neutralization and removal effect of the carbonate ion.

[0009] In order to ensure that all the mixed liquid flows along the serpentine flow channel in the mixer body, the baffle and the mixer body should be seamlessly connected.

[0010] In some embodiments, each of the baffle components includes a baffle and a plurality of raised reinforcing ribs, wherein the baffle is disposed on the inner side wall of the mixer body, and the plurality of raised reinforcing ribs are disposed on the baffle to enhance the turbulent mixing effect. Preferably, the baffle is disposed perpendicular to the direction of liquid flow.

[0011] In some embodiments, the raised reinforcement ribs are in the shape of a semicircle, a semi-ellipse, a hemisphere or a square.

[0012] In some embodiments, the number of the baffle components is 11 to 15, exemplified by 11, 12, 13, 14 or 15.

[0013] In some embodiments, the plurality of baffle assemblies are evenly spaced, preferably, each baffle assembly is spaced 10 to 20 cm apart, for example, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, or 20 cm apart.

[0014] In some embodiments, the heights at which the plurality of baffle assemblies are set are the same or different. Preferably, the height at which each of the baffle assemblies is set is 70% to 90% of the overall height of the mixer body (i.e., the vertical distance from the upper surface of the baffle to the top of the mixer body is 10% to 30% of the overall height of the mixer body), exemplified by 70%, 75%, 80%, 85% or 90%. This ensures that there is a gas phase space at the top of the baffle mixer to release the carbon dioxide gas generated during the mixing process, thereby keeping the baffle mixer device at a low pressure and reducing equipment requirements, thereby solving the technical problem that traditional mixers cannot be used in the mixing process and generate a large amount of gas.

[0015] In some embodiments, the shape of the baffle is not particularly limited, for example, it can be a polyhedron or other shapes. As an example, the polyhedron can be selected from, for example, a hexahedron, preferably a cube, such as a cuboid or a cube.

[0016] In some embodiments, the height of the baffle is 500-1000 mm, exemplified by 500 mm, 600 mm, 700 mm, 800 mm, or 1000 mm; the width of the baffle is 100-500 mm, exemplified by 100 mm, 200 mm, 300 mm, 400 mm, or 500 mm; the thickness of the baffle is 10 mm-20 mm, exemplified by 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm.

[0017] In some embodiments, a baffle is further provided on the first baffle along the liquid flow direction to prevent the mixed liquid from splashing.

[0018] In some embodiments, the baffle mixer further comprises a feed pipe and a discharge pipe, wherein the feed pipe is disposed on a side wall of the mixer body, and the discharge pipe is disposed at the bottom end of the mixer body. Preferably, the feed pipe for acid is lower than the feed pipe for alkaline wastewater containing carbonate ions / bicarbonate ions to prevent acid gas from overflowing.

[0019] When the acid feed pipe is set higher than the feed pipe of the alkaline wastewater containing carbonate ions / bicarbonate ions, a large amount of HCl gas will overflow from the baffle mixer along with carbon dioxide to the subsequent absorption unit as the reaction releases heat.

[0020] In some embodiments, the feed pipe and the discharge pipe are connected to the mixer body via connecting flanges.

[0021] In some embodiments, the mixer body has a rectangular or circular cross-section.

[0022] In some embodiments, the device further comprises a centrifugal pump and / or a metering pump for delivering acid and alkaline wastewater containing carbonate ions / bicarbonate ions to the feed pipe.

[0023] In some embodiments, the deflector mixer also includes a control unit, which is electrically connected to the metering pump and / or centrifugal pump and is used to adjust the outlet pressure of the metering pump and / or centrifugal pump. At the same time, the acid addition flow rate is regulated by the regulating valve, and the acid addition flow rate can also be directly regulated by the metering pump, saving the purchase and installation costs of the flow meter.

[0024] In some embodiments, the baffle mixer is further provided with an exhaust port for releasing carbon dioxide gas, and the exhaust port is connected to the buffer unit through a pipeline.

[0025] In some embodiments, the baffle mixer is further provided with a plurality of sight glass observation ports to facilitate observation of the baffles and liquid levels in the baffle mixer and preventive inspection of equipment damage.

[0026] The present invention arranges baffles within a baffle mixer perpendicular to or at an angle to the direction of liquid flow. The baffle height is controlled to be 70%-90% of the overall mixer height, with a spacing of 10-20 cm between adjacent baffles. The number and spacing of the baffles can be increased based on the processing flow rate and mixing requirements. Raised reinforcing ribs are also provided on the baffles, increasing the support strength of the mixer baffles while enhancing the turbulent mixing effect of acid and alkaline wastewater containing carbonate / bicarbonate ions within the baffle mixer. The height of the baffles ensures that a gas phase space remains above the baffle mixer to release carbon dioxide generated during the mixing process, thereby maintaining a low pressure within the baffle mixer and reducing equipment requirements. Multiple viewing ports are provided above the baffle mixer for observing internal baffles, liquid levels, and preventing damage. The baffle mixer is designed to meet the processing volume and material properties, with a Reynolds number of 5000 or above to achieve high turbulence and improve mixing efficiency.

[0027] According to an embodiment of the present invention, the buffer unit is, for example, a buffer tank.

[0028] According to an embodiment of the present invention, the device further comprises a pH detection unit, which is connected to the buffer unit for real-time monitoring of the pH value of the liquid in the buffer unit.

[0029] In some embodiments, the pH detection unit may be, for example, a pH meter.

[0030] According to an embodiment of the present invention, the device further comprises a conveying unit, which is connected to the buffer unit and is used to convey the treated wastewater to a sewage treatment device or other deep treatment device for recycling.

[0031] The present invention also provides a method for removing carbonate ions from wastewater, comprising mixing acid with alkaline wastewater containing carbonate ions / bicarbonate ions in the above-mentioned device, and removing the carbonate ions / bicarbonate ions in the alkaline wastewater through an acid-base neutralization reaction.

[0032] According to an embodiment of the present invention, the molar ratio of the hydrogen ions in the acid to the carbonate ions in the alkaline wastewater is 2 to 2.1:1, exemplified by 2.03:1.

[0033] According to an embodiment of the present invention, the acid is hydrochloric acid and / or spent acid.

[0034] For example, the concentration of the hydrochloric acid is 15-31%, and exemplary concentrations are 15%, 20% or 31%.

[0035] In some embodiments, the waste acid is, for example, wastewater containing hydrochloric acid produced as a by-product of a tetrachloroethylene plant. For example, the concentration of hydrochloric acid in the waste acid is 15-31%, exemplified by 15%, 20% or 31%.

[0036] In some embodiments, the alkaline wastewater containing carbonate ions / bicarbonate ions can be selected from alkaline wastewater in a chemical gas absorption device, for example, wastewater generated by a water washing alkali washing tower of an epichlorohydrin device.

[0037] High-concentration acid reduces the load on conveying equipment but increases the processing requirements of the subsequent HCl absorption unit. Using hydrochloric acid below 15% can reduce HCl gas overflow, but too low a concentration increases the load on post-mixing conveying and processing equipment. Therefore, the hydrochloric acid concentration should be adjusted to maximize economic benefits, taking into account both economic considerations and the processing capacity of the subsequent absorption unit.

[0038] According to an embodiment of the present invention, the reaction temperature is not higher than 40°C, for example, room temperature; the reaction residence time of the acid and the alkaline wastewater containing carbonate ions / bicarbonate ions in the baffle mixer is 10 to 40 seconds, exemplarily 30 seconds.

[0039] The theoretical reaction time between alkaline wastewater containing carbonate ions and acid is only a few seconds. By controlling the residence time of the acid and alkaline wastewater containing carbonate ions and bicarbonate ions within the baffled mixer to 10 to 40 seconds, the present invention ensures uniform mixing while allowing time for carbon dioxide gas release. A buffer unit (such as a buffer tank) located downstream of the baffled mixer can further offset fluctuations in production operations. If the mixing ratio is inappropriate or the mixing effect is poor, the reaction and carbon dioxide gas release can continue within the buffer unit.

[0040] Beneficial effects of the present invention:

[0041] (1) The existing acid-base neutralization and carbonate removal process uses a stirring and mixing method, which requires a power consumption of about 0.1 to 1 kw / m 3 The present invention adopts a baffle mixing method, which not only reduces the energy consumption required by the existing stirring and mixing method without adding additional rotating equipment, but also utilizes the residual height difference of the baffle mixer to naturally settle the neutralization reaction liquid into the buffer tank to fully release the carbon dioxide dissolved in the liquid, thereby avoiding the problem that the liquid mixed with a large number of bubbles cannot be transported by a traditional centrifugal pump.

[0042] (2) The upper portion of the baffle mixer of the present invention reserves a gas phase space to release the gas during the mixing and neutralization process, thereby maintaining a low pressure on the equipment to reduce equipment requirements, thereby solving the problem that traditional mixers cannot be used in processes that generate a large amount of gas during the mixing process.

[0043] (3) The present invention controls the pH of the mixed liquid at the outlet of the buffer unit to about 2 to 4, so that the carbonate content in the neutralized wastewater is 0. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic structural diagram of a device for removing carbonate ions from wastewater according to the present invention;

[0045] Figure 2 A top view of the baffle mixer of the present invention;

[0046] Figure 3 A side view of the baffle mixer of the present invention;

[0047] Figure 4 Schematic diagram of the three-dimensional structure of the baffle mixer of the present invention;

[0048] Among them: 1-baffle mixer; 11-mixer body; 121-baffle; 122-reinforcement rib; 123-baffle; 13-acid feed pipe; 14-alkaline wastewater feed pipe; 15-discharge pipe; 16-sightglass observation port; 17-exhaust port; 2-buffer unit; 3-unit for removing acid gas; 4-transport unit; 5-pH detection unit. DETAILED DESCRIPTION

[0049] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0050] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0051] Example 1

[0052] Reference Figure 1-4 A device for removing carbonate from wastewater comprises a baffle mixer 1, a buffer unit 2 and a unit 3 for removing acid gas, which are connected in series.

[0053]

Baffle mixer

[0054] The baffle mixer 1 comprises a mixer body 11 and a plurality of baffle components. The plurality of baffle components are staggeredly arranged inside the mixer body 11 to form a serpentine flow channel inside the mixer body 11 .

[0055] Multiple baffle components are located on different planes. The mixed liquid coming from upstream will contact and collide with each baffle component, so that the mixed liquid can be collided multiple times, thereby making the mixed liquid more evenly and fully mixed, making the neutralization reaction between the acid and carbonate ions more thorough, and thus improving the neutralization and removal effect of carbonate ions.

[0056] In order to ensure that all the mixed liquid flows along the serpentine flow channel in the mixer body 11 , the baffle 121 and the mixer body 11 should be seamlessly connected.

[0057]

Baffle assembly

[0058] Each baffle assembly includes a baffle 121 and a plurality of raised reinforcing ribs 122. The baffle 121 is arranged on the inner side wall of the mixer body 11. The plurality of raised reinforcing ribs 122 are arranged on the baffle 121 to increase the turbulent mixing effect.

[0059] Preferably, the baffle 121 is arranged perpendicular to the direction of liquid flow (it can also be arranged facing the direction of liquid flow to enhance the disturbance effect, but it will increase the difficulty of equipment manufacturing).

[0060] The number of the baffle components is 11 to 15, and exemplified by 11, 12, 13, 14 or 15.

[0061] The plurality of baffle assemblies are evenly spaced. Preferably, the spacing between each baffle assembly is 10 to 20 cm, for example, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm or 20 cm.

[0062] The multiple baffle assemblies are arranged at the same or different heights, and the height of each baffle assembly is 70% to 90% of the overall height of the mixer body 11 (i.e., the vertical distance from the upper surface of the baffle plate 121 to the top of the mixer body 11 is 10% to 30% of the overall height of the mixer body 11), exemplified by 70%, 75%, 80%, 85%, or 90%. This ensures that there is a gas phase space on the baffle mixer 1 to release the carbon dioxide gas generated during the mixing process, thereby keeping the baffle mixer 1 at a low pressure and reducing equipment requirements, thereby solving the technical problem that traditional mixers cannot be used in the mixing process because a large amount of gas is generated.

[0063] The baffle 121 is in the shape of a cuboid, and the height of the baffle 121 is 500-1000 mm, exemplified by 500 mm, 600 mm, 700 mm, 800 mm or 1000 mm; the width of the baffle 121 is 100-500 mm, exemplified by 100 mm, 200 mm, 300 mm, 400 mm or 500 mm; the thickness of the baffle 121 is 10 mm-20 mm, exemplified by 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm or 20 mm.

[0064] Along the liquid flow direction, a baffle 123 is further provided on the first baffle 121 to prevent the mixed liquid from splashing.

[0065]

Reinforcement

[0066] The raised reinforcement rib 122 is in the shape of a semicircular arch.

[0067]

Mixer body

[0068] The cross section of the mixer body 11 is rectangular. Acid-base neutralization facilities are mostly made of glass fiber reinforced plastics, and the rectangular shape is convenient for manufacturing and installation.

[0069] The baffle mixer 1 further includes a feed pipe and a discharge pipe, wherein the feed pipe is provided on the side wall of the mixer body 11, and the discharge pipe is provided at the bottom end of the mixer body 11. Preferably, the feed pipe 13 for acid is lower than the feed pipe 14 for alkaline wastewater containing carbonate ions / bicarbonate ions to prevent acid gas from overflowing.

[0070] The feed pipe and the discharge pipe are connected to the mixer body 11 through connecting flanges.

[0071] Centrifugal pump

[0072] The device further comprises a centrifugal pump, which is used for conveying the acid and the alkaline wastewater containing carbonate ions / bicarbonate ions to the feed pipe.

[0073]

Regulation control unit

[0074] The baffle mixer 1 also includes a control unit, which controls the frequency conversion of the centrifugal pump through the DCS, adjusts the outlet pressure of the centrifugal pump, and controls the acid addition flow through the regulating valve according to the pH value.

[0075] The baffle mixer 1 is further provided with an exhaust port 17 for releasing carbon dioxide gas, and the exhaust port 17 is connected to the buffer unit 2 through a pipeline.

[0076] The baffle mixer 1 is also provided with a plurality of sight glass observation ports 16, which facilitate observation of the baffles and liquid levels in the baffle mixer 1 and preventive inspection of equipment damage.

[0077] By arranging baffles 121 perpendicular to the direction of liquid flow within the baffle mixer 1, controlling the height, spacing, and / or number of baffles 121, and providing raised reinforcing ribs 123 on the baffles 121, the turbulent mixing effect of the acid and alkaline wastewater containing carbonate ions / bicarbonate ions within the baffle mixer 1 is enhanced, while also ensuring that there is a gas phase space on the baffle mixer 1 to release the carbon dioxide gas generated during the mixing process, thereby maintaining the baffle mixer 1 at a low pressure and reducing equipment requirements. Multiple sight glass observation ports 16 are also provided on the baffle mixer 1 to observe the baffles and liquid levels within the equipment and to prevent and inspect equipment damage.

[0078]

pH detection unit

[0079] The device also includes a pH detection unit 5, which is connected to the buffer unit 2 and is used to monitor the pH value of the liquid in the buffer unit 2 in real time. By installing the pH detection unit 5 at the outlet of the delivery pump of the buffer unit 2, the pH of the neutralized wastewater is detected online and the pH is controlled to 2-4 to ensure the treatment effect of carbonate ions in the wastewater.

[0080]

Conveying unit

[0081] The device further comprises a conveying unit 4, which is connected to the buffer unit 2 and is used to convey the treated wastewater to a sewage treatment device or other deep treatment device for recycling.

[0082] Example 2

[0083] In the device for removing carbonate ions from wastewater in Example 1, from January 8, 2025 to January 11, 2025, Binhua Group Co., Ltd. continuously passed the wastewater generated by the water washing alkali washing tower of the epichlorohydrin device through the alkaline wastewater feed pipe at a rate of 25m 3 / h flow rate is transported to the baffle mixer 1, and at the same time, the hydrochloric acid with a concentration of 15% produced as a by-product of the tetrachloroethylene device in the company is transported to the baffle mixer 1 through the acid feed pipe 13 (the shape of the mixer body 11 is a rectangular parallelepiped, with a length of 1500mm, a width of 500mm and a height of 1000mm; 11 baffle components are set in the mixer body 11, the shape of the baffle plate 121 is a rectangular parallelepiped, each baffle plate 121 has a height of 800mm, a width of 400mm and a thickness of 10mm, the setting height of the 11 baffle components is the same, and the setting height of each baffle component accounts for 80% of the total height of the mixer body 11, the cross section of the reinforcing rib 123 is semicircular, and each baffle component has two A total of four reinforcing ribs 123 are provided on the surface, and the horizontal spacing of each baffle assembly is 100mm. A baffle 123 is also provided on the first baffle plate 121 to prevent the mixed liquid from splashing. ) so that it is mixed and neutralized in the baffle mixer 1 (the residence time of the mixed liquid in the baffle mixer 1 is 30s), and most of the carbon dioxide gas is released through the exhaust port 17. The mixed liquid phase flows to the buffer tank below (buffer unit 2) for secondary gas-liquid separation. The neutralized wastewater in the buffer tank is eventually transported to a wet oxidation method or a biological sewage treatment facility. The gas phase absorbs the remaining acidic gases such as HCl through a water washing absorption tower, and then is discharged after mist collection by a mist collector. It can be subsequently connected to a carbon dioxide purification facility. Among them: the Na2CO3 concentration and NaHCO3 concentration of the wastewater generated by the water washing and alkali washing tower of the epichlorohydrin device before and after treatment are shown in Table 1 below:

[0084] Table 1

[0085]

[0086] Example 3

[0087] In the device for removing carbonate ions from wastewater of Example 1, from March 9 to March 10, 2025 and from March 15 to March 17, 2025, Binhua Group Co., Ltd. continuously fed the wastewater generated by the water washing alkali washing tower of the epichlorohydrin device through the alkaline wastewater feed pipe at a rate of 25m 3 / h flow rate is transported to the baffle mixer 1, and at the same time, the hydrochloric acid with a concentration of 15% produced as a by-product of the company's tetrachloroethylene device is transported to the baffle mixer 1 through the acid feed pipe 13 (the mixer body 11 is in the shape of a rectangular parallelepiped, with a length of 1500mm, a width of 500mm, and a height of 1000mm; 11 baffle components are set in the mixer body 11, the baffle plate 121 is in the shape of a rectangular parallelepiped, each baffle plate 121 is 800mm high, 400mm wide, and 10mm thick, the 11 baffle components are set at the same height, and the height of each baffle component accounts for 80% of the total height of the mixer body 11, the cross section of the reinforcing rib 123 is semicircular, and each baffle component There are four reinforcing ribs 123 on both sides, and the horizontal spacing of each baffle assembly is 100mm. The first baffle 121 is also provided with a baffle 123 for preventing the mixed liquid from splashing up, so that it is mixed and neutralized in the baffle mixer 1 (the residence time of the mixed liquid in the baffle mixer 1 is 30s). Most of the carbon dioxide gas is released through the exhaust port 17, and the mixed liquid phase flows to the buffer tank below (buffer unit 2) for secondary gas-liquid separation. The neutralized wastewater in the buffer tank is finally transported to the wet oxidation method or biological sewage treatment facility. The gas phase absorbs the remaining acidic gases such as HCl through the water washing absorption tower, and then is discharged after collecting mist in the mist collector. It can be connected to the carbon dioxide purification facility later. Among them: the Na2CO3 concentration and NaHCO3 concentration of the wastewater generated by the water washing and alkali washing tower of the epichlorohydrin device before and after treatment are shown in Table 2 below:

[0088] Table 2

[0089]

[0090]

[0091] In summary: The present invention mixes the wastewater containing hydrochloric acid (waste acid) produced as a by-product of the tetrachloroethylene device with the alkaline wastewater produced by the water washing and alkali washing tower of the epichlorohydrin device in a baffle mixer to produce a neutralization reaction, and utilizes the reinforcing ribs provided on the baffle plate of the baffle assembly to improve the strength of the baffle assembly while also enhancing the turbulent mixing effect, which can significantly reduce the overall length requirement of the equipment and thus save equipment space. The present invention controls the pH value of the mixed liquid at the liquid outlet of the buffer unit 2 to be less than 4, that is, the carbonate and / or bicarbonate in the wastewater produced by the water washing and alkali washing tower of the epichlorohydrin device can be completely removed (the removal rate is 100%, that is, no carbonate and / or bicarbonate are detected in the treated solution). Even when the pH value of the mixed liquid at the liquid outlet of the buffer unit 2 is around 6-7, the removal rate of carbonate and / or bicarbonate can still reach 85%.

[0092] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A device for removing carbonate from wastewater, characterized in that: It includes a baffle mixer, a buffer unit and a unit for removing acid gas which are connected in series in sequence; The baffle mixer comprises: a mixer body and a plurality of baffle components, wherein the plurality of baffle components are staggeredly arranged inside the mixer body to form a serpentine flow channel inside the mixer body; Each of the baffle components includes a baffle and a plurality of raised reinforcing ribs, wherein the baffle is arranged on the inner side wall of the mixer body, and the plurality of raised reinforcing ribs are arranged on the baffle; The setting height of the deflector assembly is 70% to 90% of the overall height of the mixer body.

2. The device according to claim 1, wherein The baffle is arranged perpendicular to the liquid flow direction.

3. The device according to claim 1, wherein The shape of the raised reinforcement ribs is semicircular, semi-elliptical, hemispherical or square.

4. The device according to claim 1, wherein The number of baffle components is 11 to 15; And / or, a plurality of the baffle assemblies are evenly spaced; And / or, the spacing between each deflection assembly is 10 to 20 cm.

5. The device according to claim 1, wherein The baffle is in the shape of a hexahedron; And / or, the height of the baffle is 500-1000 mm; the width of the baffle is 100-500 mm; the thickness of the baffle is 10 mm-20 mm; And / or, along the liquid flow direction, a baffle is further provided on the first baffle plate to prevent the mixed liquid from splashing.

6. The device according to any one of claims 1 to 5, characterized in that The baffle mixer further includes a feed pipe and a discharge pipe, wherein the feed pipe is arranged on the side wall of the mixer body, and the discharge pipe is arranged at the bottom end of the mixer body; The feed pipe for the acid is lower than the feed pipe for the alkaline wastewater containing carbonate ions / bicarbonate ions.

7. The device according to any one of claims 1 to 5, characterized in that The device also includes a centrifugal pump and / or a metering pump; The baffle mixer further comprises a control unit, which is electrically connected to the metering pump and / or the centrifugal pump; And / or, the baffle mixer is further provided with an exhaust port for releasing carbon dioxide gas, and the exhaust port is connected to the buffer unit through a pipeline; And / or, the deflector mixer is further provided with a plurality of mirror observation ports.

8. The device according to any one of claims 1 to 5, characterized in that The device further comprises a pH detection unit, wherein the pH detection unit is connected to the buffer unit; The device further comprises a conveying unit connected to the buffer unit.

9. A method for removing carbonate ions from wastewater, characterized in that: The method comprises mixing an acid with alkaline wastewater containing carbonate ions / bicarbonate ions in the device according to any one of claims 1 to 8, and removing the carbonate ions / bicarbonate ions in the alkaline wastewater through an acid-base neutralization reaction.

10. The method according to claim 9, wherein The molar ratio of hydrogen ions in the acid to carbonate ions in the alkaline wastewater is 2 to 2.1:1; And / or, the waste acid is wastewater containing hydrochloric acid produced as a by-product of a tetrachloroethylene device; and / or, the concentration of hydrochloric acid in the waste acid is 15 to 31%; And / or, the reaction temperature is not higher than 40° C.; the residence time of the reaction of the acid and the alkaline wastewater containing carbonate ions / bicarbonate ions in the baffle mixer is 10 to 40 seconds.

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