Low-temperature evaporative crystallization equipment

Abstract

The invention belongs to the technical field of evaporative crystallization equipment, and particularly discloses low-temperature evaporative crystallization equipment which comprises a crystallization kettle and a lubricating oil tank. A rotating shaft is arranged in the crystallization kettle, two ends of the crystallization kettle are respectively provided with a bearing chamber, a communicating hole is arranged between the crystallization kettle and the bearing chamber, a bearing for supporting the rotating shaft is arranged in the bearing chamber, and a sealing device or a sealing mechanism is arranged between the rotating shaft and the communicating hole. A lubricating oil pipeline is arranged between the lubricating oil tank and the bearing chamber, a pressure balance pipeline is arranged between the lubricating oil tank and the crystallization kettle, a plurality of paddle wheels are axially arranged on the rotating shaft at intervals, and each paddle wheel is provided with a plurality of paddles annularly distributed around the rotating shaft. A material scraping device is arranged between at least one pair of paddles of the adjacent paddle wheels, and a slag discharging opening is formed in the crystallization kettle. The problems that in the prior art, materials are prone to being discharged through the bearing chamber, and spiral propelling blades hinder material flowing are solved. The evaporation crystallization efficiency and the condensate scraping effect are remarkably improved, the gas-liquid separation efficiency is optimized, and meanwhile air pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of evaporation crystallization equipment, and particularly relates to a low-temperature evaporation crystallization equipment. Background Art

[0002] The low-temperature evaporation crystallization equipment is an industrial device that realizes solid-liquid separation by reducing the boiling point of the solution under a negative pressure environment. It is commonly used in the treatment of high-salt wastewater and is widely applied in many fields such as chemical industry, pharmacy, food, and environmental protection.

[0003] The core functional modules of the low-temperature evaporation crystallization equipment are as follows: It includes a crystallization kettle. A rotating shaft driven by a power device is arranged inside the crystallization kettle. There is a bearing chamber at each end of the crystallization kettle. A communication hole is arranged between the crystallization kettle and the bearing chamber. The end of the rotating shaft passes through the communication hole and extends into the bearing chamber. A bearing for supporting the rotating shaft is installed in the bearing chamber. A sealing device is arranged between the rotating shaft and the communication hole. Helical propulsion blades are arranged on the rotating shaft.

[0004] The working mode of the above low-temperature evaporation crystallization equipment is as follows: After the material is input into the crystallization kettle, the kettle body is evacuated and heated, so that the material boils at a lower temperature. The generated steam flows to the condensation heat exchanger. The material in the kettle gradually concentrates and crystallizes. The helical propulsion blades push the crystals outwards from the slag discharge port.

[0005] The problems existing in the existing low-temperature evaporation crystallization equipment are as follows: 1. The crystallization kettle usually maintains a negative pressure environment, but in some cases (such as the shutdown of the vacuum system, abnormal chemical reactions, out-of-control heat energy input, and blockage of the exhaust pipeline), positive pressure will occur in the kettle. Although there is the sealing effect of the sealing device, a small amount of material will still enter the bearing chamber through the gap between the rotating shaft and the communication hole, and then leak out through the bearing chamber. The material in the crystallization kettle is usually harmful. Once leaked, it will cause environmental pollution. 2. The helical propulsion blades have a strong blocking effect on the flow of the material in the crystallization kettle, resulting in difficulty in exhausting the gas in the kettle, and thus reducing the efficiency of material concentration and crystallization. Summary of the Invention

[0006] The purpose of the present invention is to provide a low-temperature evaporation crystallization equipment, aiming to solve the problem that the material in the crystallization kettle is easy to leak out through the bearing chamber when the pressure in the crystallization kettle changes in the prior art.

[0007] To solve the above problems, the low-temperature evaporation crystallization equipment disclosed by the present invention includes a crystallization kettle. A rotating shaft driven by a power device is arranged in the crystallization kettle. A rotary sweeping device is arranged on the rotating shaft. There is a bearing chamber at each end of the crystallization kettle. A communication hole is arranged between the crystallization kettle and the bearing chamber. The end of the rotating shaft passes through the communication hole and extends into the bearing chamber. A bearing for supporting the rotating shaft is installed in the bearing chamber. A sealing device or sealing mechanism is arranged between the rotating shaft and the communication hole. The low-temperature evaporation crystallization equipment further includes a lubricating oil tank. A lubricating oil pipeline connecting the two is arranged between the lubricating oil tank and the bearing chamber. A pressure balance pipeline connecting the two is arranged between the lubricating oil tank and the crystallization kettle. After adopting the above structure, lubricating oil can be placed in the lubricating oil tank. By arranging the lubricating oil tank, the lubricating oil in the lubricating oil tank can enter the bearing chamber. By arranging a pressure balance pipeline between the lubricating oil tank and the crystallization kettle, the lubricating oil tank and the crystallization kettle are kept in pressure balance. In this way, the bearing chamber is always filled with lubricating oil. Whether there is negative pressure or positive pressure in the crystallization kettle, it is very difficult for the materials in the crystallization kettle to enter the bearing chamber, and there will be no leakage situation.

[0008] Further, two chambers are arranged in the lubricating oil tank at left and right intervals. One of them is an isobaric buffer chamber, and the other is a lubricating oil chamber. An air vent is arranged between the isobaric buffer chamber and the lubricating oil chamber. The isobaric buffer chamber is connected to the pressure balance pipeline, and the lubricating oil chamber is connected to the lubricating oil pipeline. After adopting the above structure, the isobaric buffer chamber and the lubricating oil chamber are separated. Even if a small amount of materials in the crystallization kettle enter the lubricating oil tank, they only enter the isobaric buffer chamber, and will not enter the lubricating oil chamber, let alone enter the bearing chamber. The air vent is used to keep the pressure balance between the isobaric buffer chamber and the lubricating oil chamber.

[0009] Furthermore, a flow guide plate with a middle part bulging upward is arranged in the lubricating oil cavity. A cooling medium circulation pipe is arranged below the flow guide plate. The lubricating oil pipeline includes an oil supply pipe and an oil return pipe. One end of the oil supply pipe is communicated with an oil supply port arranged on the side wall of the lubricating oil cavity, and the other end of the oil supply pipe is communicated with the bearing chamber. One end of the oil return pipe is communicated with an oil return port arranged on the side wall of the lubricating oil cavity, and the other end of the oil return pipe is communicated with the bearing chamber. A pressure balance interface for connecting a pressure balance pipeline is arranged on the side wall of the equal-pressure buffer cavity. The pressure balance interface is lower than the ventilation port. A sewage discharge port is arranged on the bottom wall of the equal-pressure buffer cavity. After adopting the above structure, the flow guide plate can guide the lubricating oil entering from the oil return port to flow downward, prevent the lubricating oil from directly impacting the cooling medium circulation pipe, and in addition, can also prevent the lubricating oil below from splashing upward; the cooling medium circulation pipe can circulate the cooling medium to cool the lubricating oil flowing back to the lubricating oil cavity; the lubricating oil absorbs heat in the bearing chamber and is cooled again in the lubricating oil cavity, thereby forming a thermosiphon effect, and the lubricating oil can naturally circulate in the lubricating oil pipeline including the oil supply pipe and the oil return pipe; the pressure balance interface is used to connect the pressure balance pipeline. Since the pressure balance interface is lower than the ventilation port, even if materials enter the equal-pressure buffer cavity from the pressure balance interface, the materials will not enter the lubricating oil cavity. The sewage discharge port is used to discharge the materials entering the equal-pressure buffer cavity.

[0010] Secondly, the present invention further improves the low-temperature evaporation crystallization equipment to solve the problem that the spiral propelling blades in the prior art block the flow of materials in the crystallization kettle. The further improvement of the low-temperature evaporation crystallization equipment lies in that: the rotary sweeping device includes a plurality of paddle wheels axially arranged at intervals on the rotating shaft. The paddle wheels have a plurality of paddle blades distributed around the rotating shaft. A material scraping device for scraping the materials on the inner wall of the crystallization kettle is arranged between at least a pair of paddle blades of adjacent paddle wheels. A slag discharge port that can be opened and closed is arranged on the crystallization kettle. After adopting the above structure, by arranging paddle wheels on the rotating shaft and arranging a material scraping device between the paddle blades of adjacent paddle wheels, the existing spiral propelling blades can be replaced. When the paddle wheels rotate slowly, they have a stirring effect, which can make the materials in the crystallization kettle be heated evenly. The material scraping device can scrape the solidified substances attached to the inner wall of the crystallization kettle. After the paddle wheels increase their rotation speed, they can convey the scraped solidified substances to one end of the crystallization kettle and discharge them outward through the opened slag discharge port. The paddle wheels have multiple functions of stirring, conveying solidified substances, and supporting the material scraping device, and will not block the flow of materials in the crystallization kettle.

[0011] Furthermore, the paddle wheel has three blades, and there are three kinds of material scraping devices provided between three pairs of blades of adjacent paddle wheels; the first kind of material scraping device includes a plurality of first connecting frames arranged between two blades, and a plurality of scraping teeth are arranged at intervals along the axial direction of the rotating shaft on the first connecting frame; the second kind of material scraping device includes a second connecting frame arranged between two blades, and a plurality of fixed scraping plates are arranged at intervals along the axial direction of the rotating shaft on the second connecting frame; the third kind of material scraping device includes a third connecting frame arranged between two blades, and a plurality of movable scraping plates are arranged at intervals along the axial direction of the rotating shaft on the third connecting frame, and the movable scraping plates are installed on the third connecting frame in a manner that can slide radially along the rotating shaft, and an elastic buffer element is provided between the movable scraping plates and the third connecting frame. After adopting the above structure, the three kinds of material scraping devices have a progressive scraping effect on the adhered and solidified substances on the inner wall of the crystallization kettle. The scraping teeth of the first kind of material scraping device partially scrape the adhered and solidified substances on the inner wall of the crystallization kettle, making the remaining part of the adhered and solidified substances looser and easier to scrape; the fixed scraping plates of the second kind of material scraping device have a further scraping effect on the adhered and solidified substances; the movable scraping plates of the third kind of material scraping device can fit with the kettle wall of the crystallization kettle, so as to scrape the solidified substances on the kettle wall of the crystallization kettle clean; the combination of the three kinds of material scraping devices can improve the scraping effect on the adhered and solidified substances on the inner wall of the crystallization kettle.

[0012] Furthermore, at least three paddle wheels are provided on the rotating shaft, and the material scraping devices between different paddle wheels on the rotating shaft are arranged in rows along the axial direction of the rotating shaft, and the types of adjacent two material scraping devices in the same row are different; if the number of material scraping devices in the same row is greater than or equal to three, the types of adjacent three material scraping devices are all different. After adopting the above structure, the three kinds of material scraping devices are arranged in sequence along the circumferential direction and are regularly arranged along the axial direction. Cooperating with each paddle wheel can realize the gradual advancement of the cleaning of the solidified substances in the crystallization kettle, and is beneficial to balancing the forces in all directions of the rotating shaft.

[0013] Furthermore, the fixed scraping plate is inclined to one side with respect to the rotation direction of the rotating shaft, the movable scraping plate is inclined to one side with respect to the rotation direction of the rotating shaft, the blade is in a twisted shape and the end of the blade far from the rotating shaft is inclined to one side with respect to the rotation direction of the rotating shaft, and the inclination directions of the fixed scraping plate, the movable scraping plate and the end of the blade far from the rotating shaft are the same. After adopting the above structure, the fixed scraping plate, the movable scraping plate and the blade are inclined, which is beneficial to reducing the resistance and improving the crushing and scraping effect on the solidified substances. The three of them adopt the same inclination direction, and the three of them can form a good cooperation, which is beneficial to the crushing and output of the solidified substances.

[0014] Furthermore, the crystallization kettle is connected with an air outlet pipeline, and a spiral separator and a condensation heat exchanger are successively arranged on the air outlet pipeline along the flow direction of the internal fluid; the air outlet pipeline is connected with an air suction device, and the air suction device includes a water production tank, a circulation pump and a jet ejector. The water production tank, the circulation pump and the jet ejector are connected in series through a water circulation pipeline, and the air suction port of the jet ejector is communicated with the air outlet pipeline. After adopting the above structure, the hot gas generated after the material in the crystallization kettle boils is separated into gas and liquid through the spiral separator and then enters the condensation heat exchanger for condensation. The gas after water removal enters the water circulation pipeline through the air suction port of the jet ejector. The water production tank stores water, the circulation pump makes water flow in the water circulation pipeline, and the jet ejector has a Venturi effect, forming a vacuum low-pressure area at the air suction port. A vacuum low-pressure is formed in the crystallization kettle through the air outlet pipeline, and harmful substances in the gas are dissolved in water, avoiding air pollution caused by direct exhaust.

[0015] Furthermore, the crystallization kettle is connected with an air outlet pipeline, and a spiral separator is arranged on the air outlet pipeline. The spiral separator includes a separator shell, and the separator shell includes an outer cylinder. The lower end of the outer cylinder is connected with a cone cylinder whose diameter gradually decreases from top to bottom. The upper end of the outer cylinder is provided with a cylinder cover. An inner cylinder is arranged in the inner cavity of the separator shell. The lower end of the inner cylinder is connected with the middle part of the cone cylinder, and there is a gap between the upper end of the inner cylinder and the cylinder cover. The lower end of the cone cylinder is provided with a separator inlet communicated with the inner cylinder, and the separator inlet is used to communicate with the steam outlet arranged on the crystallization kettle. The separator outlet is arranged on the outer cylinder near the cone cylinder, and double spiral blades are arranged between the outer cylinder and the inner cylinder. The separator outlet is located below the double spiral blades. A cleaning pipeline is arranged at a position near the top in the inner cavity of the separator shell. After adopting the above structure, the steam coming out of the crystallization kettle first enters the inner cylinder, is blocked by the cylinder cover and then enters the space between the inner cylinder and the outer cylinder, forming a spiral air flow under the guidance of the double spiral blades. The liquid droplets with larger density are thrown to the bottom, and the dry gas flows outwards through the separator outlet. The cleaning pipeline can be ventilated or watered to clean the inside of the spiral separator.

[0016] Furthermore, the crystallization kettle is arranged horizontally, and a feed inlet is arranged on the crystallization kettle; a slag discharge valve is installed at the slag discharge port of the crystallization kettle; a jacket is arranged at the bottom of the crystallization kettle, and a heating medium cavity is formed between the jacket and the main kettle body of the crystallization kettle. A heating medium inlet and a heating medium outlet are arranged on the jacket. After adopting the above structure, the feed inlet can be connected with a feeding system to supply materials into the crystallization kettle. The slag discharge valve is used to open and close the slag discharge port, and the solidified matter can be discharged after being opened. The heating medium inlet and the heating medium outlet can be connected with a heating medium supply system, and the heating medium enters the heating medium cavity to heat the materials inside the crystallization kettle.

[0017] In summary, the beneficial effects of the present invention are as follows: The present invention solves the problem in the prior art that when the pressure in the crystallization kettle changes, the materials in the kettle are likely to leak out through the bearing chamber; at the same time, it overcomes the problem in the prior art that the spiral propulsion blade blocks the flow of materials in the crystallization kettle and affects the material concentration and crystallization efficiency; the improved low-temperature evaporation crystallization equipment significantly improves the evaporation and crystallization efficiency, improves the scraping effect on the solidified matter, avoids the hidden danger of material leakage, improves the gas-liquid separation efficiency, and reduces the pollution caused by the exhaust gas evacuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of an embodiment of the present invention; Figure 2 is Figure 1 a schematic diagram of the main structure in the shown embodiment; Figure 3 is Figure 1 a sectional view of the shown embodiment; Figure 4 is Figure 3 a sectional view along line A-A in ; Figure 5 is an enlarged view of a partial structure at B in 3; Figure 6 is a schematic structural diagram of an embodiment of the lubricating oil tank, bearing chamber and their connecting pipelines in the present invention; Figure 7 is a schematic diagram of an embodiment of the connection structure of the rotating shaft, paddle wheel and material scraping device in the present invention; Figure 8 is Figure 7 a schematic structural diagram in the front view direction; Figure 9 is Figure 7 an enlarged view of a partial structure in ; Figure 10 Figure 1 a structural sketch of the shown embodiment.

[0019] In the figure: 1, crystallization kettle; 2, power device; 3, rotating shaft; 4, bearing chamber; 5, communication hole; 6, bearing; 7, sealing device; 8, lubricating oil tank; 9, lubricating oil pipeline; 10, pressure balance pipeline; 11, isobaric buffer chamber; 12, lubricating oil chamber; 13, vent port; 14, deflector; 15, cooling medium circulation pipe; 16, oil supply pipe; 17, oil return pipe; 18, oil supply port; 19, oil return port; 20, pressure balance interface; 21, sewage outlet; 22, paddle wheel; 23, paddle blade; 24, material scraping device; 25, first connecting frame; 26, scraping teeth; 27, second connecting frame; 28, fixed scraper; 29, third connecting frame; 30, movable scraper; 31, elastic buffer element; 32, gas outlet pipeline; 33, spiral separator; 34, condensation heat exchanger; 35, water production tank; 36, circulation pump; 37, ejector; 38, water circulation pipeline; 39, separator shell; 40, outer cylinder; 41, conical cylinder; 42, cylinder cover; 43, inner cylinder; 44, separator inlet; 45, separator outlet; 46, double spiral blade; 47, feed port; 48, slag discharge port; 49, slag discharge valve; 50, jacket; 51, heating medium chamber; 52, heating medium inlet; 53, heating medium outlet; 54, cleaning pipeline. Detailed implementation manners

[0020] The following combines the drawings and embodiments to further describe in detail the specific implementation manners of the present invention.

[0021] Refer to Figure 1 、 Figure 3 In some embodiments of the present invention, the low-temperature evaporation crystallization device includes a crystallization kettle 1, and a rotating shaft 3 driven by a power device 2 is arranged in the crystallization kettle 1. Figure 1 The power device 2 in Figure 1 is a motor. Sprockets are installed on both the power output shaft of the motor and the rotating shaft 3, and the sprockets are connected by a chain (the chain is not shown in Figure 3 、 Figure 5 to achieve power transmission. A rotary sweeping device is arranged on the rotating shaft 3, and there is a bearing chamber 4 at each end of the crystallization kettle 1. Refer to Figure 1 、 Figure 6, the low-temperature evaporation crystallization device further includes a lubricating oil tank 8. A lubricating oil pipeline 9 connecting the two is provided between the lubricating oil tank 8 and the bearing chamber 4, and a pressure balance pipeline 10 connecting the two is provided between the lubricating oil tank 8 and the crystallization kettle 1. After the above improvements, lubricating oil can be placed in the lubricating oil tank 8 of the low-temperature evaporation crystallization device. By providing the lubricating oil tank 8, the lubricating oil in the lubricating oil tank 8 can enter the bearing chamber 4. By providing the pressure balance pipeline 10 between the lubricating oil tank 8 and the crystallization kettle 1, the lubricating oil tank 8 and the crystallization kettle 1 are kept in pressure balance. In this way, the bearing chamber 4 is always filled with lubricating oil. Whether there is negative pressure or positive pressure in the crystallization kettle 1, it is very difficult for the materials in the crystallization kettle 1 to enter the bearing chamber 4, and there will be no leakage situation.

[0022] Refer to Figure 6 , in some embodiments of the present invention, two chambers are provided in the lubricating oil tank 8 at left and right intervals. One of them is an isobaric buffer chamber 11, and the other is a lubricating oil chamber 12. An air vent 13 is provided between the isobaric buffer chamber 11 and the lubricating oil chamber 12. The isobaric buffer chamber 11 is connected to the pressure balance pipeline 10, and the lubricating oil chamber 12 is connected to the lubricating oil pipeline 9. After the above improvements, the isobaric buffer chamber 11 and the lubricating oil chamber 12 are separated. Even if a small amount of the materials in the crystallization kettle 1 enter the lubricating oil tank 8, they only enter the isobaric buffer chamber 11, and will not enter the lubricating oil chamber 12, let alone enter the bearing chamber 4. The air vent 13 is used to keep the pressure balance between the isobaric buffer chamber 11 and the lubricating oil chamber 12.

[0023] Refer to Figure 6, in some embodiments of the present invention, a flow guiding plate 14 with a middle part bulging upward is provided in the lubricating oil cavity 12. A cooling medium circulation pipe 15 is provided below the flow guiding plate 14. The lubricating oil pipeline 9 includes an oil supply pipe 16 and an oil return pipe 17. One end of the oil supply pipe 16 communicates with an oil supply port 18 provided on the side wall of the lubricating oil cavity 12, and the other end of the oil supply pipe 16 communicates with the bearing chamber 4. One end of the oil return pipe 17 communicates with an oil return port 19 provided on the side wall of the lubricating oil cavity 12, and the other end of the oil return pipe 17 communicates with the bearing chamber 4; a pressure balance interface 20 for connecting a pressure balance pipeline 10 is provided on the side wall of the equal-pressure buffer cavity 11. The pressure balance interface 20 is lower than the air vent 13. A sewage discharge port 21 is provided on the bottom wall of the equal-pressure buffer cavity 11. A valve can be installed at the sewage discharge port 21, which is usually closed and opened during sewage discharge. After the above improvements, the flow guiding plate 14 can guide the lubricating oil entering from the oil return port 19 to flow downward, preventing the lubricating oil from directly impacting the cooling medium circulation pipe 15. In addition, it can also prevent the lubricating oil below from splashing upward. The cooling medium circulation pipe 15 can circulate the cooling medium to cool the lubricating oil flowing back to the lubricating oil cavity 12; the lubricating oil absorbs heat in the bearing chamber 4 and is cooled again in the lubricating oil cavity 12, thereby forming a thermosiphon effect, and the lubricating oil can naturally circulate in the lubricating oil pipeline 9 including the oil supply pipe 16 and the oil return pipe 17. Of course, a circulation pump can also be provided on the lubricating oil pipeline 9 to achieve the circulating flow of the lubricating oil, and the cooling medium circulates in the cooling medium circulation pipe 15 to cool the lubricating oil. The pressure balance interface 20 is used to connect the pressure balance pipeline 10. Since the pressure balance interface 20 is lower than the air vent 13, even if materials enter the equal-pressure buffer cavity 11 from the pressure balance interface 20, the materials will not enter the lubricating oil cavity 12. The sewage discharge port 21 is used to discharge the materials entering the equal-pressure buffer cavity 11.

[0024] Refer to Figure 7 , Figure 8 , Figure 9 , in some embodiments of the present invention, the rotary sweeping device includes a plurality of paddle wheels 22 axially spaced on the rotating shaft 3. The paddle wheels 22 have a plurality of paddle blades 23 distributed around the rotating shaft 3. A material scraping device 24 for scraping the materials on the inner wall of the crystallization kettle 1 is provided between at least a pair of paddle blades 23 of adjacent paddle wheels 22. The crystallization kettle 1 is provided with an openable slag discharge port 48. After the above improvements, by providing the paddle wheels 22 on the rotating shaft 3 and the material scraping device 24 between the paddle blades 23 of adjacent paddle wheels 22, the existing spiral propelling blades can be replaced. When the paddle wheels 22 rotate slowly, they have a stirring effect, which can make the materials in the crystallization kettle 1 be heated evenly. The material scraping device 24 can scrape the solidified substances attached to the inner wall of the crystallization kettle 1. After the paddle wheels 22 increase their rotation speed, they can convey the scraped solidified substances to one end of the crystallization kettle 1 and discharge them out through the opened slag discharge port 48. The paddle wheels 22 have multiple functions of stirring, conveying solidified substances, and supporting the material scraping device 24, and will not block the flow of materials in the crystallization kettle 1.

[0025] Referring to Figure 7 、 Figure 8 、 Figure 9 , in some embodiments of the present invention, the paddle wheel 22 has three blades 23, and there are three kinds of material scraping devices 24 provided between three pairs of blades 23 of adjacent paddle wheels 22; the first kind of material scraping device 24 includes a plurality of first connecting frames 25 provided between two blades 23, and a plurality of scraping teeth 26 are arranged at intervals along the axial direction of the rotating shaft 3 on the first connecting frames 25; the second kind of material scraping device 24 includes a second connecting frame 27 provided between two blades 23, and a plurality of fixed scraping plates 28 are arranged at intervals along the axial direction of the rotating shaft 3 on the second connecting frames 27; the third kind of material scraping device 24 includes a third connecting frame 29 provided between two blades 23, and a plurality of movable scraping plates 30 are arranged at intervals along the axial direction of the rotating shaft 3 on the third connecting frames 29, and the movable scraping plates 30 are installed on the third connecting frames 29 in a manner that can slide radially along the rotating shaft 3, and an elastic buffer element 31 is provided between the movable scraping plates 30 and the third connecting frames 29. In the illustrated embodiment, a plurality of through holes are provided on the third connecting frames 29, two guide posts are connected to the movable scraping plates 30, each of the two guide posts passes through a through hole on a third connecting frame 29, a limit stop block is provided at one end of the guide post away from the movable scraping plate 30, and the elastic buffer element 31 includes a spring sleeved on the guide post, and two ends of the spring respectively abut against the movable scraping plate 30 and the third connecting frame 29. After the above improvements, the three kinds of material scraping devices 24 have a progressive scraping effect on the adhered and solidified substances on the inner wall of the crystallization kettle 1. The scraping teeth 26 of the first kind of material scraping device 24 scrape off part of the adhered and solidified substances on the inner wall of the crystallization kettle 1, making the remaining part of the adhered and solidified substances looser and easier to scrape; the fixed scraping plates 28 of the second kind of material scraping device 24 have a further scraping effect on the adhered and solidified substances; the movable scraping plates 30 of the third kind of material scraping device 24 can fit with the kettle wall of the crystallization kettle 1, so as to scrape off the solidified substances on the kettle wall of the crystallization kettle; the combination of the three kinds of material scraping devices can improve the scraping effect on the adhered and solidified substances on the inner wall of the crystallization kettle 1.

[0026] Referring to Figure 7 、 Figure 8 、 Figure 9, in some embodiments of the present invention, at least three paddle wheels 22 are provided on the rotating shaft 3. The material scraping devices 24 between different paddle wheels 22 on the rotating shaft 3 are arranged in a row along the axial direction of the rotating shaft 3, and the types of adjacent two material scraping devices 24 in the same row are different; if the number of material scraping devices 24 in the same row is greater than or equal to three, the types of adjacent three material scraping devices 24 are all different. After the above improvement, the three material scraping devices 24 are arranged in sequence along the circumferential direction and regularly arranged along the axial direction. Cooperating with each paddle wheel 22 can realize the gradual advancement of the cleaning of the solidified matter in the crystallization kettle 1, and is beneficial to balancing the forces in all directions of the rotating shaft 3. The fixed scraper 28 is inclined to one side with respect to the rotating direction of the rotating shaft 3, the movable scraper 30 is inclined to one side with respect to the rotating direction of the rotating shaft 3, the paddle blade 23 is twisted, and the end of the paddle blade 23 away from the rotating shaft 3 is inclined to one side with respect to the rotating direction of the rotating shaft 3. The inclination directions of the fixed scraper 28, the movable scraper 30, and the end of the paddle blade 23 away from the rotating shaft 3 are the same. After the above improvement, the fixed scraper 28, the movable scraper 30, and the paddle blade 23 are inclined, which is beneficial to reducing resistance and improving the crushing and scraping effects on the solidified matter. The three adopt the same inclination direction, and the three can form a good cooperation, which is beneficial to the crushing and output of the solidified matter.

[0027] Refer to Figure 1 , Figure 2 , Figure 10 , in some embodiments of the present invention, the crystallization kettle 1 is connected with an air outlet pipeline 32. Along the flowing direction of the internal fluid, a spiral separator 33 and a condensation heat exchanger 34 are sequentially arranged on the air outlet pipeline 32; the air outlet pipeline 32 is connected with an air suction device. The air suction device includes a water production tank 35, a circulation pump 36, and a jet ejector 37. The water production tank 35, the circulation pump 36, and the jet ejector 37 are connected in series through a water circulation pipeline 38, and the air suction port of the jet ejector 37 is communicated with the air outlet pipeline 32. After the above improvement, the hot gas generated after the material in the crystallization kettle 1 boils is subjected to gas-liquid separation through the spiral separator 33 and then enters the condensation heat exchanger 34 for condensation. The gas after water removal enters the water circulation pipeline 38 through the air suction port of the jet ejector 37. The water production tank 35 stores water. The circulation pump 36 makes water flow in the water circulation pipeline 38. The jet ejector 37 has a Venturi effect and forms a vacuum low-pressure area at the air suction port, so as to form a vacuum low-pressure in the crystallization kettle 1 through the air outlet pipeline 32, and the harmful substances in the gas are dissolved in water, avoiding air pollution caused by direct evacuation.

[0028] Refer to Figure 3 , Figure 4, in some embodiments of the present invention, the spiral separator 33 includes a separator housing 39. The separator housing 39 includes an outer cylinder 40. A conical cylinder 41 with a diameter gradually decreasing from top to bottom is connected to the lower end of the outer cylinder 40. A cylinder cover 42 is provided at the upper end of the outer cylinder 40. An inner cylinder 43 is provided in the inner cavity of the separator housing 39. The lower end of the inner cylinder 43 is connected to the middle part of the conical cylinder 41. There is a gap between the upper end of the inner cylinder 43 and the cylinder cover 42. A separator inlet 44 communicating with the inner cylinder 43 is provided at the lower end of the conical cylinder 41. The separator inlet 44 is used to communicate with the steam outlet provided on the crystallization kettle 1. A separator outlet 45 is provided on the outer cylinder 40 near the conical cylinder 41. A double spiral blade 46 is provided between the outer cylinder 40 and the inner cylinder 43. The separator outlet 45 is located below the double spiral blade 46. A cleaning pipeline 54 is provided at a position near the top in the inner cavity of the separator housing 39. Of course, a liquid discharge port is also provided on the separator housing 39 for discharging the separated liquid. After adopting the above structure, the steam coming out of the crystallization kettle 1 first enters the inner cylinder 43. After being blocked by the cylinder cover 42, it enters the space between the inner cylinder 43 and the outer cylinder 40. Under the guidance of the double spiral blade 46, a spiral air flow is formed. The liquid droplets with a larger density are thrown to the bottom. The dry gas flows outwards through the separator outlet 45. The cleaning pipeline 54 can be ventilated or watered to clean the inside of the spiral separator 33.

[0029] Referring to Figure 3 , Figure 10 , in some embodiments of the present invention, the crystallization kettle 1 is horizontally arranged. A feed inlet 47 is provided on the crystallization kettle 1. A feed pipeline can be connected at the feed inlet 47 and connected to a feed system through the feed pipeline. A feed valve can be provided on the feed pipeline. A slag discharge valve 49 is installed at the slag discharge port 48 of the crystallization kettle 1. The opening and closing of the slag discharge port 48 are realized by controlling the slag discharge valve 49. A jacket 50 is provided at the bottom of the crystallization kettle 1. A heating medium cavity 51 is formed between the jacket 50 and the main kettle body of the crystallization kettle 1. A heating medium inlet 52 and a heating medium outlet 53 are provided on the jacket 50.

[0030] After adopting the above structure, the feed inlet 47 can be connected to a feeding system to supply materials into the crystallization kettle 1. The slag discharge valve 49 is used to realize the opening and closing of the slag discharge port 48. After opening, the solidified matter can be discharged. The heating medium inlet 52 and the heating medium outlet 53 can be connected to a heating medium supply system. The heating medium enters the heating medium cavity 51 to heat the materials inside the crystallization kettle 1.

[0031] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and replacements can still be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.

Claims

1. A low-temperature evaporation crystallization device, comprising a crystallization kettle (1). A rotating shaft (3) driven by a power device (2) is arranged inside the crystallization kettle (1). A rotary sweeping device is arranged on the rotating shaft (3). There is a bearing chamber (4) at each end of the crystallization kettle (1). A communication hole (5) is arranged between the crystallization kettle (1) and the bearing chamber (4). The end of the rotating shaft (3) passes through the communication hole (5) and extends into the bearing chamber (4). A bearing (6) for supporting the rotating shaft (3) is installed in the bearing chamber (4). A sealing device (7) or a sealing mechanism is arranged between the rotating shaft (3) and the communication hole (5). It is characterized in that, The low-temperature evaporation crystallization equipment further includes a lubricating oil tank (8). A lubricating oil pipeline (9) communicating the two is provided between the lubricating oil tank (8) and the bearing chamber (4), and a pressure balance pipeline (10) communicating the two is provided between the lubricating oil tank (8) and the crystallization kettle (1).

2. The low-temperature evaporation crystallization device according to claim 1, wherein, Two chambers are arranged at left and right intervals in the lubricating oil tank (8). One of them is an isobaric buffer chamber (11), and the other is a lubricating oil chamber (12). An air vent (13) is provided between the isobaric buffer chamber (11) and the lubricating oil chamber (12). The isobaric buffer chamber (11) communicates with the pressure balance pipeline (10), and the lubricating oil chamber (12) communicates with the lubricating oil pipeline (9).

3. The low-temperature evaporation crystallization device according to claim 2, wherein, A flow guide plate (14) with a middle part bulging upward is arranged in the lubricating oil chamber (12). A cooling medium circulation pipe (15) is arranged below the flow guide plate (14). The lubricating oil pipeline (9) includes an oil supply pipe (16) and an oil return pipe (17). One end of the oil supply pipe (16) communicates with an oil supply port (18) arranged on the side wall of the lubricating oil chamber (12), the other end of the oil supply pipe (16) communicates with the bearing chamber (4), one end of the oil return pipe (17) communicates with an oil return port (19) arranged on the side wall of the lubricating oil chamber (12), and the other end of the oil return pipe (17) communicates with the bearing chamber (4); a pressure balance interface (20) for connecting the pressure balance pipeline (10) is arranged on the side wall of the isobaric buffer chamber (11), the pressure balance interface (20) is lower than the air vent (13), and a sewage discharge port (21) is arranged on the bottom wall of the isobaric buffer chamber (11).

4. The low-temperature evaporation crystallization device according to claim 1, wherein, The rotary sweeping device includes a plurality of paddle wheels (22) axially arranged at intervals on the rotating shaft (3). The paddle wheels (22) have a plurality of paddle blades (23) distributed around the rotating shaft (3). A material scraping device (24) for scraping the materials on the wall of the crystallization kettle (1) is arranged between at least a pair of paddle blades (23) of adjacent paddle wheels (22). A slag discharge port (48) that can be opened and closed is arranged on the crystallization kettle (1).

5. The low-temperature evaporation crystallization device according to claim 4, wherein, The paddle wheel (22) has three paddle blades (23). Three material scraping devices (24) are arranged between the three pairs of paddle blades (23) of adjacent paddle wheels (22); the first material scraping device (24) includes a plurality of first connecting frames (25) arranged between two paddle blades (23), and a plurality of scraping teeth (26) are axially arranged at intervals on the first connecting frames (25) along the rotating shaft (3); the second material scraping device (24) includes a second connecting frame (27) arranged between two paddle blades (23), and a plurality of fixed scraping plates (28) are axially arranged at intervals on the second connecting frames (27) along the rotating shaft (3); the third material scraping device (24) includes a third connecting frame (29) arranged between two paddle blades (23), and a plurality of movable scraping plates (30) are axially arranged at intervals on the third connecting frames (29) along the rotating shaft (3). The movable scraping plates (30) are installed on the third connecting frames (29) in a manner that can slide radially along the rotating shaft (3), and an elastic buffer element (31) is arranged between the movable scraping plates (30) and the third connecting frames (29).

6. The low-temperature evaporation crystallization device according to claim 5, wherein, At least three paddle wheels (22) are provided on the rotating shaft (3). The material scraping devices (24) between different paddle wheels (22) on the rotating shaft (3) are arranged in a row along the axial direction of the rotating shaft (3), and the types of adjacent two material scraping devices (24) in the same row are different; if the number of the material scraping devices (24) in the same row is greater than or equal to three, the types of adjacent three material scraping devices (24) are all different.

7. The low-temperature evaporation crystallization device according to claim 5, characterized in that, The fixed scraper (28) is inclined to one side with respect to the rotation direction of the rotating shaft (3), the movable scraper (30) is inclined to one side with respect to the rotation direction of the rotating shaft (3), the paddle blade (23) is twisted and the end of the paddle blade (23) away from the rotating shaft (3) is inclined to one side with respect to the rotation direction of the rotating shaft (3), and the inclination directions of the fixed scraper (28), the movable scraper (30) and the end of the paddle blade (23) away from the rotating shaft (3) are the same.

8. The low-temperature evaporation crystallization device according to claim 1, wherein, The crystallization kettle (1) is connected with an air outlet pipeline (32), and a spiral separator (33) and a condensation heat exchanger (34) are successively arranged on the air outlet pipeline (32) along the flowing direction of the internal fluid; the air outlet pipeline (32) is connected with an air suction device, and the air suction device includes a water production tank (35), a circulation pump (36) and a jet pump (37). The water production tank (35), the circulation pump (36) and the jet pump (37) are connected in series through a water circulation pipeline (38), and the air suction port of the jet pump (37) is communicated with the air outlet pipeline (32).

9. The low-temperature evaporation crystallization device according to claim 1, characterized in that, The crystallization kettle (1) is connected with an air outlet pipeline (32), a spiral separator (33) is arranged on the air outlet pipeline (32), the spiral separator (33) includes a separator shell (39), the separator shell (39) includes an outer cylinder body (40), the lower end of the outer cylinder body (40) is connected with a conical cylinder (41) whose diameter gradually decreases from top to bottom, the upper end of the outer cylinder body (40) is provided with a cylinder cover (42), an inner cylinder body (43) is arranged in the inner cavity of the separator shell (39), the lower end of the inner cylinder body (43) is connected with the middle part of the conical cylinder (41), there is a gap between the upper end of the inner cylinder body (43) and the cylinder cover (42), the lower end of the conical cylinder (41) is provided with a separator inlet (44) communicated with the inner cylinder body (43), the separator inlet (44) is used for communicating with the steam outlet arranged on the crystallization kettle (1), a separator outlet (45) is arranged on the outer cylinder body (40) near the conical cylinder (41), a double spiral blade (46) is arranged between the outer cylinder body (40) and the inner cylinder body (43), the separator outlet (45) is located below the double spiral blade (46), and a cleaning pipeline (54) is arranged at a position near the top in the inner cavity of the separator shell (39).

10. The low-temperature evaporation crystallization device according to claim 1, characterized in that The crystallization kettle (1) is horizontally arranged, and a feed inlet (47) is arranged on the crystallization kettle (1); a slag discharge valve (49) is installed at the slag discharge port (48) of the crystallization kettle (1); a jacket (50) is arranged at the bottom of the crystallization kettle (1), a heating medium cavity (51) is formed between the jacket (50) and the main kettle body of the crystallization kettle (1), and a heating medium inlet (52) and a heating medium outlet (53) are arranged on the jacket (50).

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