Dynamic sodium sulfate crystallization device

Abstract

The utility model discloses a dynamic sodium sulfate crystallization device which comprises a crystallizer without a salt foot structure and a forced circulation heat exchanger, a material outlet is formed in the lowest end of the crystallizer, a material inlet is formed in the side wall above the material outlet, a circulating material inlet and a circulating material outlet are formed in the forced circulation heat exchanger, the circulating material inlet is communicated with the material outlet through a pipeline, and the circulating material outlet is communicated with the circulating material outlet through a pipeline. The circulating material outlet is communicated with the material inlet through a pipeline, and the pipeline between the circulating material inlet and the material outlet is also communicated with a raw material liquid pipeline; the pipeline between the circulating material inlet and the material outlet is also connected with a thickening kettle through a discharging pipeline and a discharging pump. Through the crystallizer without the salt foot structure and the forced circulation heat exchanger, crystallized sodium sulfate crystals continue to exist in materials and are in circulating motion, and the problem that in the prior art, sodium sulfate crystals settle and adhere to a salt foot outlet and a pipeline, and consequently blockage is caused is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to wastewater treatment technical field, concretely relates to a dynamic sodium sulfate crystallization device. BACKGROUND

[0002] MVR is the abbreviation of mechanical vapor recompression. Its process is to reuse the energy of the secondary steam it produces itself, thereby reducing the demand for external energy, an energy-saving technology, which is widely used in the separation of solution and solute in the field of water treatment, which is composed of a forced circulation pump, a crystallizer, a thickening kettle and a centrifuge.

[0003] At present, in the application of MVR to the separation of sodium sulfate wastewater, the crystallizer is communicated with the forced circulation pump and the thickening kettle, which is used for evaporative crystallization of the wastewater circulating in the crystallizer generated by the forced circulation pump, and the crystallized wastewater is gravity settled into the salt leg structure or the settling chamber, thereby forming a high-salt-content salt-containing mother liquor, which flows to the thickening kettle through the salt leg outlet of the salt leg structure or the crystal slurry outlet of the settling chamber, and then flows to the centrifuge for centrifugation.

[0004] However, in actual application, the salt content of the salt-containing mother liquor is extremely high, and because the crystallizer has a bucket-shaped opening structure at the salt leg outlet, the cross-sectional area changes dramatically here, so the salt leg outlet is often blocked by the accumulation of salt particles precipitated from the salt-containing mother liquor after a short period of use, and after the blockage, the salt-containing mother liquor can only be discharged after cleaning, thereby affecting the long-term smooth operation of the MVR related components. UTILITY MODEL CONTENT

[0005] To solve the above-mentioned technical problems, this utility model provides a dynamic sodium sulfate crystallization device, including a crystallizer without a salt foot structure and a forced circulation heat exchanger; the lowest end of the crystallizer is a material outlet, and a material inlet is provided on the side wall above the material outlet; the forced circulation heat exchanger is provided with a circulating material inlet and a circulating material outlet; the circulating material inlet is connected to the material outlet through a pipe, and the circulating material outlet is connected to the material inlet through a pipe; a raw material liquid pipe is also connected to the pipe between the circulating material inlet and the material outlet; the pipe between the circulating material inlet and the material outlet is also connected to a thickening vessel through a discharge pipe and a discharge pump. By using a crystallizer without a salt foot structure and a forced circulation heat exchanger, the crystallizer has a material inlet and a material outlet, and the forced circulation heat exchanger has a circulating material inlet and a circulating material outlet. The four are connected by pipelines to form a circulation. The material (sodium sulfate solution) heated by the forced circulation heat exchanger enters the crystallizer for evaporation. Then, the crystallized sodium sulfate crystals continue to exist in the material (sodium sulfate solution) and are in circulation. At the same time, the design has been redesigned to remove the salt foot structure, and the solution containing sodium sulfate crystals is directly guided into the thickening vessel through the discharge pipe and discharge pump for operation. This simplifies the device and operation and avoids the problem of sodium sulfate crystals settling and adhering to the salt foot outlet and pipes, causing blockage, which is common in the prior art.

[0006] In one embodiment, a forced circulation pump is installed on the pipeline between the material outlet and the circulating material inlet. By installing a forced circulation pump on the circulation pipeline, the material circulation between the crystallizer and the forced circulation heat exchanger is further guaranteed.

[0007] In one embodiment, the pipeline between the circulating material inlet and the material outlet includes at least a vertically or inclined discharge pipe directly connected to the material outlet. By placing the material outlet at the bottom of the crystallizer, the number of interfaces and bends is reduced. Simultaneously, the vertically or inclined discharge pipe allows the material containing sodium sulfate crystals in the crystallizer to fall rapidly. Combined with a forced circulation pump, this further reduces the probability of sodium sulfate crystals adhering to the pipe wall, ensuring reliable material circulation.

[0008] In one embodiment, the thickening vessel is also connected to a centrifuge. By using the centrifuge, the thickened slurry in the thickening vessel is further processed and dehydrated to obtain sodium sulfate crystals.

[0009] Furthermore, the clarified liquid outlet of the thickening vessel and the centrifugal liquid outlet of the centrifuge are connected to a mother liquor tank via pipelines. By providing a mother liquor tank, the clarified liquid from the thickening vessel and the centrifugal liquid from the centrifuge can be stored.

[0010] Further, the mother liquor tank is also communicated with the pipeline between the circulating material inlet and the material outlet through a mother liquor pump and a pipeline. By setting the mother liquor pump and the corresponding pipeline, the mixed liquid of the supernatant of the thick cauldron in the mother liquor tank and the centrifugal liquid of the centrifugal machine is added to the material circulation between the crystallizer and the forced circulation heat exchanger, which further heats the evaporative crystallization sodium sulfate crystals, reduces the discharge of waste water, and improves the yield of sodium sulfate crystals. At the same time, by adding the supernatant and the centrifugal liquid, the pipeline can be cleaned in the material lifting stage, and the attachment of crystals on the pipe wall is reduced.

[0011] In an embodiment, the steam outlet of the crystallization separator is communicated with a steam mechanical compressor through a secondary steam pipeline; the secondary steam pipeline comprises a horizontal inlet pipe before the secondary steam inlet of the steam mechanical compressor, an inlet pipe higher than the horizontal inlet pipe and connected to the other end of the horizontal inlet pipe, and a remaining pipeline; the inlet pipe is a vertical inlet pipe or an inclined inlet pipe; at the position where the horizontal inlet pipe and the inlet pipe are connected, the inlet pipe continues to extend axially below the horizontal inlet pipe to form a liquid accumulation tank or the inlet pipe is connected to a liquid accumulation tank through a connecting pipe arranged below the horizontal inlet pipe. By the above arrangement, the problem of effectively utilizing the energy of the secondary steam of the crystallization separator can be solved. Further, by changing the position and structure of the condensate water drainage port in the secondary steam pipeline, the condensate water in the secondary steam is greatly reduced, thereby reducing the impact of the condensate water on the blades of the steam mechanical compressor and ensuring the stability of the steam mechanical compressor. Specifically, by changing the position of the drainage port, the position of the drainage port on the lower pipe wall of the horizontal inlet pipe is moved to the end position of the horizontal drainage pipe. The principle is that the condensate water in the secondary steam directly falls into the extended part of the inlet pipe or the connecting pipe through gravity before the secondary steam in the inlet pipe enters the horizontal inlet pipe. At this time, the content of condensate water in the secondary steam entering the horizontal inlet pipe is greatly reduced. At the same time, there is basically no condensate water at the bottom of the horizontal inlet pipe, and since the length of the horizontal inlet pipe is generally set to be relatively short, there is even less condensate water formed at the bottom of the horizontal inlet pipe, reducing secondary carrying (specifically, the airflow blows the condensate water at the bottom of the horizontal inlet pipe, and then carries the condensate water into the steam mechanical compressor). Therefore, the condensate water in the secondary steam entering the steam mechanical compressor is greatly reduced, ensuring the stability of the operation. Specifically, there are two technical solutions, one is to set the inlet pipe extension to form a liquid accumulation tank, and the other is to connect a liquid accumulation tank through a connecting pipe, wherein the thickness of the part of the connecting pipe connecting the inlet pipe is close to or the same as the thickness of the inlet pipe.

[0012] In one embodiment, a liquid blocking net is arranged in the pipeline at the connection between the horizontal air inlet pipe and the air inlet pipe. By arranging the liquid blocking net, condensed water in the secondary steam can be adhered to the net and reduced in speed when passing through the liquid blocking net, so as to facilitate dripping.

[0013] In one embodiment, a liquid blocking structure is arranged in the pipeline of the air inlet pipe extension or in the connecting pipe. By arranging the liquid blocking structure, the secondary steam can be prevented from impacting the liquid that has dripped into the liquid accumulation tank, so as to form secondary carrying and affect the stable operation of the steam mechanical compressor.

[0014] Further, the liquid blocking structure is a mesh structure or a plate structure with openings. The condensed water can be dripped, and the liquid caused by impact can be blocked.

[0015] In one embodiment, the liquid blocking structure is a horn structure. The above functions are further realized, so that the liquid caused by impact can be blocked to flow down along the side wall, and the effect is better.

[0016] In one embodiment, a liquid accumulation pump connected to the liquid accumulation tank is further included, and the liquid accumulation pump pumps away the water in the liquid accumulation tank. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the drawings needed in the specific embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0018] Figure 1 is a structural schematic diagram of a dynamic sodium sulfate crystallization device of the present application;

[0019] Figure 2 is a structural schematic diagram of another dynamic sodium sulfate crystallization device of the present application;

[0020] Figure 3 is a schematic diagram of the discharge of condensed water in the prior art;

[0021] Figure 4 is Figure 2 is an enlarged structural schematic diagram of A in FIG.

[0022] Figure 5 is Figure 2 is another enlarged structural schematic diagram of A in FIG.

[0023] The figure mark represents: 1-steam mechanical compressor; 2-horizontal air inlet pipe; 3-drain pipe; 4-liquid accumulation tank; 5-liquid accumulation pump; 6-air inlet pipe; 7-connection pipe; 8-liquid blocking net; 9-liquid blocking structure; 10-crystallizer; 11-forced circulation heat exchanger; 12-material outlet; 13-material inlet; 14-circulating material inlet; 15-circulating material outlet; 16-raw material liquid pipe; 17-discharge pipe; 18-discharge pump; 19-thick kettle; 20-forced circulation pump; 21-discharge pipe; 22-centrifuge; 23-clear liquid outlet; 24-centrifugal liquid outlet; 25-mother liquor tank; 26-mother liquor pump; 27-steam outlet. DETAILED DESCRIPTION

[0024] The content of the present application will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the present application all belong to the protection scope of the present application.

[0025] In the description of the present application, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0026] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0027] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0028] Example 1

[0029] As Figure 1As shown, the embodiment discloses a dynamic sodium sulfate crystallization device, which comprises a crystallizer 10 without a salt foot structure or a settling chamber or a crystallization chamber and a forced circulation heat exchanger 11, and the absence of the salt foot structure or the settling chamber or the crystallization chamber is an improvement point of the design. Specifically, the above-mentioned structure is removed from the existing crystallization separator, and after the removal, the crystallizer 10 is formed. Of course, the crystallizer 10 can also be designed with reference to the above-mentioned structure. In this way, the port of the conical cylinder structure of the crystallization separator forms a material outlet 12 of the crystallizer 10. A material inlet 13 is arranged on the side wall above the material outlet 12. The forced circulation heat exchanger 11 is provided with a circulating material inlet 14, a circulating material outlet 15, a heat exchange medium inlet, and a heat exchange medium outlet. The heat exchange medium is generally steam. The circulating material inlet 14 is communicated with the material outlet 12 through a pipeline. The circulating material outlet 15 is communicated with the material inlet 13 through a pipeline, so that the crystallizer 10 and the forced circulation heat exchanger 11 form a circulating channel. The process is that the sodium sulfate solution material heated by the forced circulation heat exchanger 11 enters the crystallizer 10 for evaporation crystallization. The evaporated water vapor is discharged through the steam outlet 27 arranged at the top, and the crystals continue to circulate in the solution. The position of the sodium sulfate solution material entering the circulating channel is not limited. In the embodiment, the pipeline between the circulating material inlet 14 and the material outlet 13 is connected with a raw material liquid pipeline 16. The sodium sulfate solution material enters the circulating channel along the raw material liquid pipeline 16 for circulation. The pipeline between the circulating material inlet 14 and the material outlet 13 is also connected with a discharge pipeline 17 and a discharge pump 18 to connect a thickening kettle 19. In this way, the solution containing sodium sulfate crystals can enter the thickening kettle 19 through the discharge pipeline 17 for thickening, and then the thickened crystal slurry enters a centrifuge 22 for centrifugal treatment. Preferably, the inlet position of the discharge pipeline is located above the inlet position of the sodium sulfate solution material entering the circulating channel, so as to prevent the low-concentration solution not subjected to heating and crystallization from entering the thickening kettle 19.

[0030] Further, a forced circulation pump 20 is arranged on the pipeline between the material outlet 12 and the circulating material inlet 13, so as to further ensure the circulation of the material in the circulating channel.

[0031] In an embodiment, the pipeline between the circulating material inlet 13 and the material outlet 12 at least comprises a vertical or inclined discharge pipe 21 directly connected with the material outlet 12. That is, the material outlet 12 is directly connected with at least a vertical or inclined pipe body, which is named as the discharge pipe 21. The roughness of the discharge pipe 21 is generally a rough pipe body, such as an inner diameter of 40 cm or 50 cm. The length of the discharge pipe 21 is preferably about 3-10 m, and 10 m is the best.

[0032] Furthermore, the clear liquid outlet 23 of the thickening vessel 19 and the centrifugal liquid outlet 24 of the centrifuge 22 are connected to the mother liquor tank 25 through pipes, that is, the thickened clear liquid and the centrifuged centrifugal liquid enter the mother liquor tank 25 for storage.

[0033] Furthermore, the mother liquor tank 25 is also connected to the pipeline between the circulating material inlet 14 and the material outlet 12 via a mother liquor pump 26 and a pipeline. That is, the liquid material stored in the mother liquor tank 25 is sent into the circulation channel for further heating, evaporation, and crystallization via the mother liquor pump 26. The connection point is generally lower than the inlet position of the sodium sulfate solution material entering the circulation channel.

[0034] It should be noted that various valves will be installed on the above pipelines for ease of control or maintenance, which will not be described in detail here.

[0035] Example 2

[0036] like Figure 2 and Figure 4 As shown, this embodiment discloses a dynamic sodium sulfate crystallization device, which is a further design of Embodiment 1. The steam outlet 27 of the crystallizer 10 is connected to the steam mechanical compressor 1 through a secondary steam pipe. The secondary steam entering the steam mechanical compressor 1 is mechanically compressed and then enters the forced circulation heat exchanger 12 as a heat exchange medium through a pipe. The secondary steam pipe includes a horizontal inlet pipe 2 before the secondary steam inlet of the steam mechanical compressor 1, an inlet pipe 6 that is higher than the horizontal inlet pipe 2 and connected to the other end of the horizontal inlet pipe 2, and the remaining pipe. The horizontal inlet pipe 2 is the conventional inlet pipe of the steam mechanical compressor 1, and its length is determined according to the device design, but it is generally not too long, about 1m to 2m, but not limited to this range. The inlet pipe 6 is a vertical inlet pipe or an inclined inlet pipe, which refers to the setting angle of the inlet pipe, which can be determined according to the overall device design. A vertical structure is preferred, that is, a vertical inlet pipe. In this case, the droplets contained in the secondary steam are more likely to drip downwards due to gravity. At the connection between the horizontal intake pipe 2 and the intake pipe 6, the intake pipe 6 extends axially or extends below the horizontal intake pipe to form a liquid collection tank 4. The mechanism of this extension is not specifically limited, but preferably it is a single pipe. The horizontal intake pipe 2 is perpendicularly connected to this pipe or at an angle. Preferably, they are a three-way structure. The portion above the horizontal intake pipe 2 is the intake pipe 6, and the portion below the horizontal intake pipe 2 has its opening closed to form the liquid collection tank 4. To better illustrate this design, refer to the drainage design of the secondary steam pipeline before entering the steam mechanical compressor 1 in the prior art, such as... Figure 3As shown, the bottom of the horizontal air inlet pipe is communicated with the liquid accumulation tank 4 through the thinner drain pipe 3. By comparison, the design changes the outlet position of the condensed water in the secondary steam and the slow drainage speed of the drain pipe 3 in the prior art, which is generally a 1-inch pipe, and the problem of water accumulation at the bottom of the horizontal air inlet pipe 2. In the design, the air inlet pipe 6 is generally selected to have a pipe diameter of 18 inches or 20 inches, of course, not limited to the above size settings. The greatly reduced gas-liquid carrying can further reduce the impact of liquid on the compressor blades and improve stability.

[0037] In an embodiment, a liquid blocking net 8 is arranged in the pipeline at the connection between the horizontal air inlet pipe 2 and the air inlet pipe 6. The specific position is not limited, as long as the secondary steam is at the position to enter the horizontal air inlet pipe 2. The setting direction is not limited, which can be horizontal, vertical, or inclined, according to the setting position. Of course, it can also be inclined at 45 degrees, as shown in the embodiment. Figure 4 The pore size of the liquid blocking net 8 is not limited.

[0038] In an embodiment, a liquid blocking structure 9 is arranged in the pipeline of the extended part of the air inlet pipe 6. The structure of the liquid blocking structure 9 is not limited, which can be a mesh body or a plate body with liquid falling openings, and the shape is not limited. In the embodiment, the liquid blocking structure 9 is a horn mouth structure, as shown. Figure 4

[0039] In an embodiment, a liquid accumulation pump 5 connected with the liquid accumulation tank 4 is further included, which is used to pump away the accumulated water in the liquid accumulation tank 4 for use elsewhere. The operation of the liquid accumulation pump 9 can be set with a timer, a float limiting starting device, an observation window, and the like, which will not be described one by one.

[0040] Regarding the secondary steam, after coming out of the steam outlet, it can also be defoamed by a defoamer before entering the steam mechanical compressor.

[0041] Embodiment 3

[0042] As shown in the drawings, Figure 5 ​As shown, the embodiment discloses a dynamic sodium sulfate crystallization device, which is a further transformation of embodiment 2, and specifically as follows: at the position of the connection between the horizontal gas inlet pipe 2 and the gas inlet pipe 6, the gas inlet pipe 6 is connected with the liquid accumulation tank 4 through a connecting pipe 7 arranged below the horizontal gas inlet pipe 2. Specifically, the gas inlet pipe 6, the horizontal gas inlet pipe 2 and the connecting pipe 7 form a three-way structure, and the structure of the connecting pipe 7 is not limited, which can be a regular-shaped pipe or an irregular-shaped pipe. In this embodiment, the connecting pipe 7 is in a funnel-shaped structure. Figure 5 As shown.

[0043] The use process of the utility model is as follows:

[0044] The sodium sulfate solution enters the forced circulation heat exchanger 11 through the circulating material inlet 14 along the raw material liquid pipeline 16 for heating and temperature rising, and then enters the crystallizer 10 through the circulating material outlet 15 along the pipeline through the material inlet 13 for volatilization crystallization. In this process, the sodium sulfate crystals are mixed in the solution, and the water vapor after volatilization becomes secondary steam which is discharged from the steam outlet 27. The mixed solution mixed with sodium sulfate crystals enters the pipeline through the material outlet 12, part of which enters the forced circulation heat exchanger 12 along the pipeline to continue the cycle of heating and temperature rising and volatilization crystallization, and part of which enters the thickening kettle 19 for thickening through the discharge pipeline 17, and then the crystal slurry enters the centrifuge 22 for centrifugation, and the thickened clear liquid and the centrifuged liquid enter the mother liquor tank 25 for storage, and the above-mentioned solution can also enter the circulating channel through the mother liquor pump 26 along the pipeline for further volatilization crystallization. The secondary steam enters the steam mechanical compressor 1 for mechanical compression after entering the secondary steam pipeline, and then enters the forced circulation heat exchanger 11 as a heat exchange medium.

[0045] As for the source steam inlet and outlet of the forced circulation heat exchanger 11, that is, the heat exchange medium inlet and the heat exchange medium outlet, no specific limitation is made here, and existing technologies can be used. The dynamic description in the design is a definition of the circulating state of the sodium sulfate crystals obtained in the crystallizer for continuing to circulate in the circulating pipeline.

[0046] Obviously, the above-mentioned embodiments are only examples for clear illustration, and are not limitations on the embodiments. Based on the above-mentioned description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the utility model.

Claims

1. A dynamic sodium sulfate crystallization apparatus, characterized by, The crystallizer and the forced circulation heat exchanger are not provided with salt foot structure; the lowermost end of the crystallizer is a material outlet, a material inlet is arranged on the sidewall above the material outlet, the forced circulation heat exchanger is provided with a circulating material inlet and a circulating material outlet, the circulating material inlet is communicated with the material outlet through a pipeline, the circulating material outlet is communicated with the material inlet through a pipeline, and a raw material liquid pipeline is further communicated with the pipeline between the circulating material inlet and the material outlet; the pipeline between the circulating material inlet and the material outlet is further connected with a thickening kettle through a discharge pipeline and a discharge pump.

2. The dynamic sodium sulfate crystallization apparatus of claim 1, wherein, A forced circulation pump is arranged on the pipeline between the material outlet and the circulating material inlet.

3. The dynamic sodium sulfate crystallization apparatus of claim 1, wherein, The pipeline between the circulating material inlet and the material outlet at least comprises a vertical or inclined discharge pipeline directly connected with the material outlet.

4. The dynamic sodium sulfate crystallization apparatus of claim 1, wherein, The thickening kettle is further connected with a centrifugal machine.

5. The dynamic sodium sulfate crystallization apparatus of claim 4, wherein, A clear liquid outlet of the thickening kettle and a centrifugal liquid outlet of the centrifugal machine are communicated with a mother liquor tank through a pipeline.

6. The dynamic sodium sulfate crystallization apparatus of claim 5, wherein, The mother liquor tank is further communicated with the pipeline between the circulating material inlet and the material outlet through a mother liquor pump and a pipeline.

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