MVR (Mechanical Vapor Recompression) evaporating crystallizer with three-stage defoaming function

Abstract

The utility model discloses an MVR (Mechanical Vapor Recompression) evaporating crystallizer with a three-stage defoaming function. The MVR evaporating crystallizer comprises a first cylindrical section, a second cylindrical section, a first conical section, a third cylindrical section and a second conical section which are sequentially arranged from top to bottom, the diameter of the first cylindrical section is smaller than that of the second cylindrical section; the diameter of the third cylindrical section is smaller than that of the first cylindrical section; according to the device, three-stage defoaming is arranged, a main body is arranged to be in the shape similar to a waist drum, the diameter of the middle of the evaporator is large, a sufficient evaporation space can be provided, a large boiling surface is formed, and the flash evaporation efficiency is improved; when a gas-liquid mixed phase obtained after boiling, evaporation and gasification enters the secondary gas-liquid defoaming section, the flow speed of the gas-liquid mixed phase is increased, the high flow speed is formed so that liquid drops can be conveniently removed, the better defoaming effect is achieved, the crystallized salt settling section with the small diameter is adopted, more liquid stays in the evaporation chamber in the middle, and the purpose of rapid gasification is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of evaporation crystallization equipment, in particular to an MVR evaporation crystallizer with three-stage defoaming. Background Art

[0002] At present, most enterprises use MVR multi-effect evaporation crystallizer to treat wastewater containing salt and organic high boiling substances. Because the wastewater contains organic high boiling substances, the secondary steam produces a lot of foam, and the secondary steam outlet carries a lot of foam and liquid, which enters the secondary steam compressor, causing the compressor to carry liquid and salt to precipitate in the compressor, causing the compressor to stop. The normal operation of the compressor requires the removal of foam, droplets and foam from the steam at the compressor inlet, and clean steam can enter the compressor. Moreover, the compressor is designed and manufactured according to the inlet suction pressure and discharge section pressure required by the original process, and the total pressure drop of the defoaming and defoaming device (including the total pressure drop from the inlet, including internal parts, to the outlet) is required to be no more than 2kpa; the diameter of the evaporation chamber for treating wastewater is mostly designed to be about 5000mm, and the clearance height of the evaporation chamber is 8250mm. For such a large volume of evaporation chamber, it is almost ineffective to remove droplets and foam and defoam by simple gravity sedimentation, and the maintenance cost of adding defoaming agent is too high, which affects the entire production. Utility Model Content

[0003] The utility model aims to overcome the disadvantage that the liquid foam generated when treating wastewater containing organic high boiling substances in the existing multi-effect evaporation crystallizer affects production, and provides an MVR evaporation crystallizer with three-stage defoaming.

[0004] The purpose of the utility model is achieved through the following technical scheme: an MVR evaporation crystallizer with three-stage defoaming, comprising a main body, a hydrocyclone defoamer, a blade defoamer, and a flap defoamer; characterized in that: the main body comprises a first cylindrical section, a second cylindrical section, a first conical section, a third cylindrical section, and a second conical section which are arranged in sequence from top to bottom; the straight diameter of the first cylindrical section is smaller than the straight diameter of the second cylindrical section; the diameter of the third cylindrical section is smaller than the diameter of the first cylindrical section; the hydrocyclone defoamer, the blade defoamer, and the flap defoamer are arranged at the upper end of the first cylindrical section; a feed liquid inlet is arranged at the middle and lower end of the second cylindrical section, a material outlet is arranged on the first conical section, and the feed liquid inlet and the material outlet are arranged opposite to each other.

[0005] Optionally, a washing spray system is arranged above the blade demister; a washing spray system is arranged below the cyclone demister; the washing spray system is directly opposite the cyclone demister and the blade demister; a rotary spray system is arranged between the cyclone demister and the blade demister, and the rotary spray system is directly opposite the cyclone demister and the blade demister.

[0006] Optionally, the flap demister includes an outer cylinder, a baffle, an inner cylinder, and a steam outlet; the outer cylinder includes an upper wall, an annular side wall, and a lower wall, the upper wall is sealed above the annular side wall, and the lower wall is sealed below the annular side wall; the inner cylinder includes a baffle and an annular condensation plate; the upper part of the annular condensation plate is tightly connected to the baffle, the lower part of the annular condensation plate is connected to the lower wall of the outer cylinder, an air flow channel is provided between the lower part of the annular condensation plate and the lower wall of the outer cylinder, the lower wall of the outer cylinder is tightly connected to the air inlet pipe of the main body, the upper part of the air inlet pipe passes through the baffle of the inner cylinder, a gap is provided between the upper part of the air inlet pipe and the baffle, the annular side wall of the outer cylinder is connected to the steam outlet, and the lower part of the air inlet pipe is provided above the blade demister.

[0007] Optionally, the lower wall of the outer cylinder is connected to and passes through the condensate discharge pipe.

[0008] Optionally, the blade demister includes a corrugated plate and a fixed frame, the corrugated plates are overlapped in the fixed frame, the corrugated plates are spaced apart from each other, both ends of the corrugated plates are fixed by the fixed frame, and the fixed frame is connected to the inner wall of the main body.

[0009] Optionally, the corrugated plate includes an outer corner plate, an inner corner plate, a blade bottom baffle, a blade top baffle, and a connecting plate; the outer corner plate, the inner corner plate and the connecting plate are arranged in a "Z" shape, one end of the outer corner plate is fixedly set on the fixed frame, one end of the inner corner plate is connected to the middle plate of the outer corner plate, one end of the connecting plate is connected to the middle plate of the inner corner plate, a blade bottom baffle is arranged at the middle plate of the connecting plate to be connected to the fixed frame, and a blade top baffle with a bending angle is arranged at the top of the outer corner plate.

[0010] Optionally, the cyclone demister includes a vessel wall, a cover tube, swirl blades, and a center column; the cover tube is configured as a plate adapted to the cross-sectional shape of the main body, the center column is configured as a columnar body adapted to the cross-sectional shape of the main body, a plurality of inclined swirl blades are arranged between the cover tube and the center column, the swirl blades are arranged at intervals from each other, and the outer side of the cover tube is connected to the inner wall of the main body.

[0011] Optionally, a liquid receiving groove is formed between the inner wall and the cover tube, and overflow ports are arranged on both sides of the liquid receiving groove.

[0012] The utility model has the following advantages:

[0013] The device is provided with three-stage defoaming and the main body is arranged to be similar to a waist drum, which is large in the middle and small at both ends. In this way, during use, due to the kinetic energy of the air pressure from large to small, the large diameter in the middle of the evaporator can provide a sufficient evaporation space, form a larger boiling surface to improve the flash evaporation efficiency, and when the gas-liquid mixed phase after boiling evaporation enters the secondary gas-liquid defoaming section, the flow rate of the gas-liquid mixed phase becomes faster due to the smaller diameter, forming a high flow rate for the escape of droplets, so as to achieve a better defoaming effect. The crystallized salt sedimentation section with a smaller diameter is adopted to allow more liquid to stay in the evaporation chamber in the middle, which is conducive to achieving the purpose of rapid gasification and reducing the influence of liquid foam on production during the treatment of organic high-boiling wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. It is obvious that the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 It is a structural schematic diagram of the utility model.

[0016] Figure 2 It is a schematic diagram of the structure of the blade demister of the utility model.

[0017] Figure 3 It is a schematic diagram of the structure of the hydrocyclone demister of the utility model.

[0018] In the figure, a main body (1), a liquid inlet (11), a material outlet (12), a salt outlet (13), a sewage outlet (14), a condensate discharge pipe (15), a washing spray system (21), a rotary spray system (22), a cyclone demister (3), an inner wall (31), a cover tube (32), a liquid receiving tank (33), an overflow port (34), a cyclone blade (35), a center column (36), a blade demister (4), a fixing frame (41), an outer corner plate (42), an inner corner plate (43), a blade bottom baffle (44), a blade top baffle (45), a flap demister (5), an outer tube (51), a baffle (52), an inner tube (53), and a steam outlet (54). DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] like Figure 1 An MVR evaporation crystallizer with three-stage defoaming is shown, comprising a main body 1, a cyclone demister 3, a blade demister 4, and a flap demister 5. In this device, in order to adapt to the combined use of multiple-stage demisters and form a unidirectional pressure on the evaporating steam, the main body 1 comprises a first cylindrical section, a second cylindrical section, a first conical section, a third cylindrical section, and a second conical section, which are arranged in sequence from top to bottom, and the diameter of the first cylindrical section is smaller than the diameter of the second cylindrical section; the diameter of the third cylindrical section is smaller than the diameter of the first cylindrical section; the cyclone demister 3, the blade demister 4, and the flap demister 5 are arranged at the upper end of the first cylindrical section; a feed liquid inlet 11 is arranged at the middle and lower end of the second cylindrical section, and a material outlet 12 is arranged on the first conical section, and the feed liquid inlet 11 and the material outlet 12 are arranged opposite to each other. As shown in FIG. Figure 1 As shown, the device is similar to a waist drum, which is large in the middle and small at both ends. In this way, during use, due to the air pressure kinetic energy from large to small, the large diameter in the middle of the entire evaporator crystallizer can provide a sufficient evaporation space, forming a larger boiling surface to improve the flash evaporation efficiency. When the gas-liquid mixed phase after boiling evaporation enters the secondary gas-liquid defoaming section, the flow rate of the gas-liquid mixed phase becomes faster due to the smaller diameter, forming a high flow rate to facilitate the escape of droplets, so as to achieve a better defoaming effect. The crystallization salt sedimentation section with a smaller diameter is used to allow more liquid to stay in the middle evaporation chamber, which is conducive to achieving the purpose of rapid gasification.

[0023] In another embodiment, in order to assist defoaming and cleaning, a washing spray system 21 is arranged above the blade demister 4; a washing spray system 21 is arranged below the cyclone demister 3; the washing spray system 21 is directly opposite to the cyclone demister 3 and the blade demister 4; a rotary spray system 22 is arranged between the cyclone demister 3 and the blade demister 4, and the rotary spray system 22 is directly opposite to the cyclone demister 3 and the blade demister 4. The rotary spray system sprays the cyclone demister demister screen and the blade demister demister in a rotating manner through the spray holes to clean them; the rotary spray system 22 and the washing spray system 21 can both be cleaned online at any time, and the combined use has a good washing effect, thereby improving the defoaming ability of the demister.

[0024] In another embodiment, Figure 1 As shown, the device provides a specific flap demister 5 including an outer tube 51, a baffle 52, an inner tube 53, and a steam outlet 54. Specifically, the outer tube 51 includes an upper wall, an annular side wall, and a lower wall. The upper part of the annular side wall is sealed and arranged with the upper wall, and the lower part of the annular side wall is sealed and arranged with the lower wall, so as to form a columnar groove cover. The inner tube 53 includes a baffle 52 and an annular condensation plate; the upper part of the annular condensation plate is tightly connected with the baffle 52, the lower part of the annular condensation plate is connected with the lower wall of the outer tube 51, and an air flow channel is arranged between the lower part of the annular condensation plate and the lower wall of the outer tube. The lower wall of the outer tube is tightly connected with the air inlet pipe of the main body 1, the upper part of the air inlet pipe passes through the inner tube baffle 52, and a gap is arranged between the upper part of the air inlet pipe and the baffle 52. The annular side wall steam of the outer tube 51 is connected with the steam outlet 54, and the lower part of the air inlet pipe is arranged above the blade demister. The lower wall of the outer tube 51 is connected and penetrated with the condensate discharge pipe 15. During use, after the steam enters the flap demister 5, the condensed water formed after adsorption and condensation by the annular condensation plate is discharged through the condensed water discharge pipe 15, and the gas after defoaming is discharged from the steam outlet 54. As a third-level defoaming device, the baffle is used to deflect the steam, which can limit the flow rate and flow rate, and also remove foam and condensed liquid droplets.

[0025] In another embodiment, Figure 2As shown, the present application provides a blade demister 4 including a corrugated plate and a fixed frame, wherein the corrugated plates are overlapped in the fixed frame, the corrugated plates are spaced apart from each other, both ends of the corrugated plates are fixed by the fixed frame, and the fixed frame is connected to the inner wall of the main body 1. Specifically, the corrugated plate includes an outer corner plate 42, an inner corner plate 43, a blade bottom baffle 44, a blade top baffle 45, and a connecting plate 46; the outer corner plate 42, the inner corner plate 43 and the connecting plate 46 are arranged in a "Z" shape, and the outer corner plate 42, the inner corner plate 43, and the connecting plate 46 are actually composed of three plates, namely two flat plates and an intermediate plate obliquely connected between two parallel plates. When setting, since gas is to pass through, the two parallel plates of the outer corner plate 42 are set vertically downward. Similarly, the connecting plate 46 is consistent with the direction of the outer corner plate 42, and the inner corner plate 43 in the middle needs to be flipped 180 degrees. The flipped inner corner plate 43 is set and connected to the lower third of the middle plate of the outer corner plate 42. Similarly, the connecting plate 46 is also connected to the lower third of the middle plate of the inner corner plate 43. Then one end of the outer corner plate 42 is fixedly set on the fixed frame 41, and a blade bottom baffle 44 is set at one-third of the lower middle plate of the connecting plate 46 to connect with the fixed frame 41, and a blade top baffle 45 with a bending angle is set at the top of the outer corner plate 42. In this way, in the whole design, the outer corner plate 42, the inner corner plate 43, the blade top baffle 45, and the connecting plate 46 constitute a corrugated plate from top to bottom, and then the plate is set to be annular or square according to the cross-sectional shape of the specific main body 1. The device adopts an annular main body 1, so the corrugated plate is also set to be annular. Multiple corrugated plates are arranged at intervals, and the connection between the plates forms a corner. In this way, during the use of time, the airflow and the contained carriers increase the formation and contact area at the corner after entering, making it easy to converge and settle. In the spray cleaning with the spray system, the foam can be eliminated as much as possible. The blade demister 4 efficiently utilizes the kinetic energy, momentum and droplet surface free energy carried by the airflow itself, and synergistically exerts a variety of separation methods including fluid momentum and kinetic energy conversion separation, vector separation, coalescence separation, surface free energy capture separation, etc., with large operational flexibility, low operating pressure drop, and stable separation efficiency. Structurally, independent conveying channels are set for gas phase flow and liquid phase flow respectively, effectively avoiding secondary entrainment of gas and liquid. The blade demister 4 can be provided with multi-stage serial separation units on the airflow channel, and any droplets and foams escaping from the previous separation unit will be continuously captured and separated by the subsequent serial separation units to ensure separation efficiency and high operational flexibility.

[0026] In another embodiment, Figure 3As shown, the device provides a cyclone demister 3 including an inner wall 31, a cover tube 32, a swirl blade 35, and a center column 36. Specifically, the cover tube 32 is set as a plate that matches the cross-sectional shape of the main body 1, and the center column 36 is set as a columnar body that matches the cross-sectional shape of the main body 1. A plurality of inclined swirl blades 35 are arranged between the cover tube 32 and the center column 36. The swirl blades 35 are arranged at intervals from each other. The outer side of the cover tube is connected to the inner wall 31 of the main body, and a liquid receiving groove 33 is formed between the inner wall 31 and the cover tube 32. Overflow ports 34 are arranged on both sides of the liquid receiving groove 33. The mist in the secondary steam forms droplets on the surface of the swirl blade 35; because the swirl blade 35 is a smooth surface, the droplets fall back to the liquid receiving groove 33 due to gravity and are discharged, and the washing water of the spray system can also be discharged from the overflow port 34. The utility model has a simple structure, the swirl blade 35 is easy to replace, can be used for a long time, and can well eliminate the mist entrainment in the secondary steam.

[0027] The working process of the utility model is as follows:

[0028] The evaporation crystallizer has three sets of defoaming devices. The main body adopts a variable diameter structure. After heat exchange, the liquid enters the evaporation chamber radially from the liquid inlet. During operation, the liquid level is controlled so that the feed port is close to the liquid surface, which can ensure that the feed can quickly flow to the liquid surface. Due to the low pressure, the liquid quickly reaches the boiling point and starts flash evaporation. The use of a large diameter evaporation chamber can expand the boiling surface and improve the evaporation efficiency. After flash evaporation, a large amount of secondary steam at about 85°C carrying impurity foam moves upward under the action of suction. The first steam first passes through the cyclone demister for defoaming. When the airflow passes through the gap between the swirl blades 35, it becomes a rotating airflow. Under the action of inertia, the droplets therein are ejected at a certain elevation angle to make a spiral motion and are thrown to the liquid receiving tank 33 between the inner wall 31 and the cover tube 32. The liquid receiving tank 33 is a concave structure with an overflow port. This structure facilitates the impurity liquid to flow out from the overflow port 34, and the impurity droplets are separated from the steam to achieve the purpose of preliminary defoaming.

[0029] Then the steam passes through the blade demister 4 above. Due to the inertial impact of the gas, the mist collides with the blade baffle and the gathered droplets are so large that the gravity generated by itself exceeds the combined force of the gas's rising force and the liquid's surface tension, and the droplets are separated from the surface of the blade baffle. The multi-fold and corner structure of the blade baffle increases the chance of mist being captured. The mist that is not removed in the airflow is captured at the next turn through the same action, and the repeated action greatly improves the defoaming efficiency.

[0030] The flap demister 5 is fixed on the top of the separator body. The airflow enters from the inner cylinder and hits the top of the inner cylinder under the action of inertia, and changes direction, flowing downward along the inner wall of the inner cylinder 53. The airflow turns over from the bottom of the outer cylinder 51 and flows upward, flowing out from the material outlet, while the droplets in the airflow cannot turn over and move upward under the action of gravity, and can only flow into the separator from the condensate discharge pipe, thus achieving the purpose of defoaming. At the same time, during the defoaming process, the impurities and foams adhering to the cylinder wall, the blade demister 4 and the cyclone demister 2 are washed by the washing spray system 21 and the rotary spray system 22, which can better ensure the cleanliness of the secondary steam and greatly reduce the corrosion of equipment and pipelines such as air compressors.

[0031] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An MVR evaporation crystallizer with three-stage defoaming, comprising a main body (1), a hydrocyclone defoamer (3), a blade defoamer (4), and a flap defoamer (5); characterized in that: The main body (1) comprises a first cylindrical section, a second cylindrical section, a first conical section, a third cylindrical section, and a second conical section, which are arranged in sequence from top to bottom; the diameter of the first cylindrical section is smaller than the diameter of the second cylindrical section; the diameter of the third cylindrical section is smaller than the diameter of the first cylindrical section; the cyclone demister (3), the blade demister (4), and the flap demister (5) are arranged at the upper end of the first cylindrical section; a liquid feed inlet (11) is arranged at the middle and lower end of the second cylindrical section, and a material outlet (12) is arranged on the upper part of the first conical section, and the liquid feed inlet (11) and the material outlet (12) are arranged opposite to each other.

2. The MVR evaporation crystallizer with three-stage defoaming according to claim 1, characterized in that: A washing spray system (21) is arranged above the blade demister (4); a washing spray system (21) is arranged below the cyclone demister (3); the washing spray system (21) faces the cyclone demister (3) and the blade demister (4); a rotary spray system (22) is arranged between the cyclone demister (3) and the blade demister (4); the rotary spray system (22) faces the cyclone demister (3) and the blade demister (4).

3. The MVR evaporation crystallizer with three-stage defoaming according to claim 1, characterized in that: The blade demister (4) comprises a corrugated plate and a fixed frame. The corrugated plates are overlapped and arranged in the fixed frame. The corrugated plates are spaced apart from each other. Both ends of the corrugated plates are fixed by the fixed frame. The fixed frame is connected to the inner wall of the main body (1). The corrugated plate comprises an outer corner plate (42), an inner corner plate (43), a blade bottom baffle plate (44), a blade top baffle plate (45), and a connecting plate (46). The outer corner plate (42), the inner corner plate (43), and the connecting plate (46) are arranged in a "Z" shape. One end of the outer corner plate (42) is fixedly arranged on the fixed frame (41), one end of the inner corner plate (43) is connected to the middle plate of the outer corner plate (42), one end of the connecting plate (46) is connected to the middle plate of the inner corner plate (43), a blade bottom baffle plate (44) is arranged at the middle plate of the connecting plate (46) and is connected to the fixed frame (41), and a blade top baffle plate (45) with a bending angle is arranged at the top of the outer corner plate (42).

4. The MVR evaporation crystallizer with three-stage defoaming according to claim 1, characterized in that: The cyclone demister (3) comprises an inner wall (31), a cover tube (32), swirl blades (35), and a center column (36); the cover tube (32) is configured as a plate that matches the cross-sectional shape of the main body (1); the center column (36) is configured as a column that matches the cross-sectional shape of the main body (1); a plurality of inclined swirl blades (35) are arranged between the cover tube (32) and the center column (36); the swirl blades (35) are arranged at intervals; the outer side of the cover tube is connected to the inner wall (31) of the main body; a liquid receiving groove (33) is formed between the inner wall (31) and the cover tube (32); overflow ports (34) are arranged on both sides of the liquid receiving groove (33).

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