Potassium nitrate crystallization device

Abstract

The utility model relates to a potassium nitrate crystallization device and belongs to the technical field of potassium nitrate production and processing. The device mainly comprises a tank body, a stirring assembly, a heat exchange tube group, an anti-scaling wall-scraping mechanism and a discharging assembly, a conical flow guide part is arranged at the bottom of the tank body; the heat exchange efficiency of the heat exchange tube group is enhanced through fins; the anti-scaling wall scraping mechanism removes crystals through a scraping plate; the stirring assembly optimizes liquid flowing;

Description

Technical Field

[0001] This utility model belongs to the field of potassium nitrate production and processing technology, and specifically relates to a potassium nitrate crystallization device. Background Technology

[0002] Currently, in the potassium nitrate crystallization process, the crystallizer uses an external heat exchange system, that is, a jacket heat exchange is set outside the tank. The heat exchange efficiency is low, the temperature drop is uneven, and the crystals are easy to accumulate on the side wall of the tank. After the tank is scaled, the heat exchange efficiency further decreases. The potassium nitrate crystals produced are deposited at the bottom of the tank, causing scale buildup at the bottom of the tank, which can easily block the discharge port and prevent the material from being discharged. Utility Model Content

[0003] To overcome the problems of low heat exchange efficiency, uneven cooling, easy crystal accumulation and scaling on the side walls and bottom of the tank, and easy blockage of the discharge port in existing potassium nitrate crystallization devices, this utility model provides a potassium nitrate crystallization device. The device improves the cooling effect, prevents scaling, and ensures smooth discharge by using heat exchange tube groups, anti-scaling scraping mechanism, and optimized stirring components, combined with conical guide section and vibration-assisted discharge structure.

[0004] To achieve the above objectives, this utility model is implemented through the following technical solution: A potassium nitrate crystallization device mainly includes a tank, a stirring assembly, a heat exchange tube assembly, an anti-scaling scraping mechanism, and a discharge assembly. The tank has a hollow internal structure with a conical guide section at its bottom. The conical guide section is coaxially arranged with the tank and has a cone angle ranging from 120° to 150° to facilitate crystal aggregation towards the center. The surface of the conical guide section is coated with an anti-scaling coating with a thickness of 0.2 mm to 0.5 mm. The material is a polymer with high corrosion resistance and low adhesion, such as polytetrafluoroethylene, which can further reduce the tendency of crystals to deposit at the bottom. An inlet is provided at the top of the tank for introducing potassium nitrate solution, and an outlet is provided at the center of the bottom for discharging the solid product after crystallization.

[0005] The heat exchange tube assembly includes multiple vertically arranged heat exchange tubes that penetrate the top wall of the tank and extend into the inner cavity of the tank. These tubes are evenly distributed circumferentially along the top wall. Each heat exchange tube has fins on its outer wall to enhance the heat exchange area. One end is connected to the external cooling system through a cooling medium inlet pipe, and the other end is connected to a cooling medium outlet pipe. The anti-scaling scraping mechanism includes a rotating shaft, multiple scrapers, and a drive motor. The rotating shaft penetrates the top wall of the tank and extends into the inner cavity of the tank. Its upper end is fixed to the output shaft of the drive motor to achieve a transmission connection. The scrapers are evenly distributed circumferentially along the outer wall of the rotating shaft. The scrapers are equipped with a wear-resistant rubber layer with a thickness of 2mm to 3mm, which protects the inner wall of the tank and improves the scraping effect. When the drive motor drives the rotating shaft to rotate, the scrapers rotate accordingly, scraping off the crystals adhering to the inner wall of the tank to prevent scaling.

[0006] The mixing assembly includes a stirring paddle and an auxiliary dispersing disc, both of which are mounted on a rotating shaft. The stirring paddle is located in the middle of the rotating shaft and has several through holes with a diameter of 3mm to 5mm on its surface to promote liquid flow and reduce resistance. The auxiliary dispersing disc is fixed to the outer wall of the rotating shaft and located below the stirring paddle. Its surface has multiple diversion holes that are evenly distributed around the bottom surface of the auxiliary dispersing disc, which can guide the liquid to flow downward and form convection in the tank, thereby improving the mixing uniformity.

[0007] The discharge assembly includes a discharge pipe and a vibrator. The discharge pipe is fixed at the discharge port at the center of the bottom surface of the tank. Its top end penetrates the bottom wall of the tank and extends into the inner cavity of the tank. Its end is connected to an external collection device. The vibrator is fixed on the outer wall of the conical guide section. When the vibrator is started, the high-frequency vibration generated can effectively prevent crystals from accumulating or blocking in the discharge pipe, ensuring smooth discharge.

[0008] The above-mentioned components are connected in a clear manner to form an overall structure: the tank body serves as the main body to support all other components, the stirring assembly is connected to the drive motor through the rotating shaft, the scraper in the anti-scaling scraping mechanism is directly welded to the outer wall of the rotating shaft, the heat exchange tube assembly is connected to the tank body and is also connected to the cooling medium input pipe and return pipe to ensure the normal operation of the cooling system, and the discharge assembly is installed at the discharge port at the bottom of the tank body.

[0009] The beneficial effects of this utility model are:

[0010] This invention significantly improves heat exchange efficiency by replacing the traditional jacketed heat exchange method with heat exchange tube assembly. Simultaneously, the increased heat exchange area from the fins ensures more uniform cooling. The anti-scaling scraping mechanism effectively removes crystals from the inner wall of the tank, extending the equipment's service life. The stirring assembly enhances liquid flowability, reducing the formation of localized supercooled areas and thus inhibiting excessive crystal aggregation. The conical guide reduces the possibility of bottom deposition, and the vibrator in the discharge assembly solves the problem of discharge port blockage. In summary, this invention successfully overcomes the shortcomings of existing technologies, such as low heat exchange efficiency, uneven cooling, severe scaling, and difficult discharge. It is suitable for large-scale industrial production and possesses high practical value and promising prospects for widespread application. Attached Figure Description

[0011] Figure 1 This is an isometric schematic diagram of the present invention.

[0012] Figure 2 This is a top view of the structure of this utility model.

[0013] Figure 3 This is a partial cross-sectional view of the present invention.

[0014] Figure 4This is a second partial cross-sectional view of the present invention.

[0015] Figure 5 This is a partial cross-sectional view of the third part of this utility model.

[0016] In the attached diagram, the following are the reference numerals: 1. Tank body; 2. Heat exchange tube assembly; 3. Stirring assembly; 4. Anti-scaling scraping mechanism; 5. Discharge assembly; 6. Conical guide section; 9. Heat exchange tube; 10. Fin; 11. Rotating shaft; 12. Scraper; 13. Drive motor; 14. Stirring paddle; 15. Auxiliary dispersion disc; 16. Through hole; 17. Diverting hole; 18. Discharge pipe; 19. Vibrator. Detailed Implementation

[0017] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, so as to facilitate the understanding of those skilled in the art.

[0018] This utility model discloses a potassium nitrate crystallization device, such as Figure 1 , Figure 2 As shown, the potassium nitrate crystallization device mainly includes a tank 1, a heat exchange tube assembly 2, a stirring assembly 3, an anti-scaling and scraping mechanism 4, and a discharge assembly 5. The tank 1 has a cylindrical structure with a hollow interior to hold the potassium nitrate solution and complete the crystallization process. The top of the tank 1 has an inlet, and the bottom center has an outlet connected to the discharge pipe 18. The inlet and outlet are respectively equipped with an inlet valve and an outlet valve (not shown in the figure). The bottom of the tank 1 is designed as a conical guide section 6, which is fixed to the bottom of the tank 1 by welding and forms a sealed connection with the tank 1 to ensure that the liquid does not leak. The conical guide section 6 is coaxially arranged with the tank 1, and its cone angle ranges from 120° to 150° to ensure that the crystals can smoothly converge to the center. The surface of the conical guide section 6 is coated with an anti-scaling coating with a thickness of 0.2 mm to 0.5 mm, and the material is polytetrafluoroethylene to reduce the tendency of crystals to deposit at the bottom.

[0019] like Figure 3 , Figure 4 , Figure 5 As shown, the heat exchange tube assembly 2 includes multiple heat exchange tubes 9. These heat exchange tubes 9 vertically penetrate the top wall of the tank 1 and extend into the inner cavity of the tank 1. The heat exchange tubes 9 are evenly distributed around the top wall of the tank 1. One end of the heat exchange tube 9 is connected to the cooling medium inlet pipe, and the other end is connected to the cooling medium outlet pipe. Each heat exchange tube 9 has fins 10 on its outer wall. The function of the fins 10 is to increase the heat exchange area, thereby improving the cooling efficiency.

[0020] like Figure 3 , Figure 4 , Figure 5As shown, the stirring assembly 3 includes a stirring paddle 14 and an auxiliary dispersing disc 15, both of which are mounted on a rotating shaft 11. The rotating shaft 11 passes through the top wall of the tank 1 and extends into the inner cavity of the tank 1. Its upper end is fixed to the output shaft of the drive motor 13 to achieve a transmission connection. The stirring paddle 14 is located in the middle of the rotating shaft 11, and its surface has several through holes 16 with a diameter of 3 mm to 5 mm. The through holes 16 are designed to promote liquid flow and reduce resistance during the stirring process. The auxiliary dispersing disc 15 is fixed to the outer wall of the rotating shaft 11 and is located below the stirring paddle 14. Its surface has several diversion holes 17, which are evenly distributed around the bottom surface of the auxiliary dispersing disc 15. The design of the diversion holes 17 can guide the liquid to flow downward and form convection in the tank 1, thereby improving the mixing uniformity.

[0021] like Figure 3 , Figure 4 , Figure 5 As shown, the anti-scaling scraping mechanism 4 includes a rotating shaft 11, a scraper 12, and a drive motor 13. The scraper 12 is evenly distributed circumferentially along the outer wall of the rotating shaft 11. The scraper 12 is provided with a wear-resistant rubber layer with a thickness of 2mm to 3mm. This rubber layer protects the inner wall of the tank 1 and improves the scraping effect. The scraper 12 is directly welded to the outer wall of the rotating shaft 11 to ensure that it rotates synchronously with the rotating shaft 11. When the drive motor 13 drives the rotating shaft 11 to rotate, the scraper 12 rotates accordingly, scraping off the crystals adhering to the inner wall of the tank 1 to prevent scaling. The drive motor 13 is fixed to the top of the tank 1 through a flange, and its output shaft is connected to the upper end of the rotating shaft 11 through a flange to ensure the stability of the transmission.

[0022] like Figure 1 , Figure 3 , Figure 4 , Figure 5 As shown, the discharge assembly 5 includes a discharge pipe 18 and a vibrator 19. The discharge pipe 18 is fixed at the discharge port at the center of the bottom surface of the tank 1. Its top end penetrates the bottom wall of the tank 1 and extends into the inner cavity of the tank 1. Its end is connected to an external collection device. The discharge pipe 18 is sealed to the discharge port at the bottom of the tank 1 through a flange to ensure that the liquid does not leak. The vibrator 19 is fixed to the outer wall of the conical guide section 6 by bolts. When the vibrator 19 is started, the high-frequency vibration generated can effectively prevent crystals from accumulating or blocking in the discharge pipe 18 and ensure smooth discharge. The vibrator 19 is located close to the bottom of the discharge pipe 18 so as to better act on the crystals in the discharge pipe 18.

[0023] Potassium nitrate solution is introduced into tank 1 through the feed inlet. The drive motor 13 is started, driving the rotating shaft 11 to rotate, causing the stirring paddle 14 and auxiliary dispersion disc 15 to rotate synchronously. The through-hole 16 on the stirring paddle 14 and the diversion hole 17 on the auxiliary dispersion disc 15 work together to promote the flow of liquid within tank 1 and form convection, thereby improving mixing uniformity. Simultaneously, the cooling medium enters the heat exchange tube 9 through the cooling medium input pipe and achieves efficient heat exchange under the action of the fins 10, gradually cooling the potassium nitrate solution in tank 1. During the cooling process, crystals begin to precipitate and may adhere to the inner wall of tank 1. At this time, the scraper 12 of the anti-scaling scraping mechanism 4 rotates with the rotating shaft 11, removing the crystals adhering to the inner wall of tank 1. To prevent scaling, the conical guide section 6 is designed to allow crystals to converge towards the center and enter the discharge pipe 18 through the discharge port. During the discharge process, the vibrator 19 is activated, and the high-frequency vibration generated prevents crystals from accumulating or clogging in the discharge pipe 18, ensuring smooth discharge. The heat exchange tube assembly 2 replaces the traditional jacketed heat exchange method, improving heat exchange efficiency. The increased heat exchange area of ​​the fins 10 makes cooling more uniform. The anti-scaling scraping mechanism 4, combined with the wear-resistant rubber layer, not only effectively removes crystals from the inner wall of the tank 1 but also extends the service life of the equipment. The through holes 16 and diversion holes 17 in the stirring assembly 3 enhance liquid flowability and reduce the generation of local supercooled areas, thereby inhibiting excessive crystal aggregation. The conical guide section 6, combined with the application of the anti-scaling coating, significantly reduces the possibility of bottom deposition, while the vibrator 19 in the discharge assembly 5 solves the problem of discharge port blockage.

[0024] Work process:

[0025] First, a solution containing potassium nitrate enters the cavity structure inside tank 1 through the feed port at the top of tank 1. The solution inside tank 1 comes into contact with heat exchange tube assembly 2. The external cooling system delivers low-temperature cooling medium to heat exchange tube 9 through the cooling medium input pipe. The cooling medium flows inside heat exchange tube 9 and exchanges heat with the solution inside the tank through the tube wall and fins 10, causing the solution temperature to gradually decrease, thereby promoting the crystallization and precipitation of potassium nitrate. The cooled cooling medium then flows out of heat exchange tube assembly 2 through the cooling medium output pipe.

[0026] During the cooling and crystallization process of the solution, the stirring assembly 3 starts to work. When the rotating shaft 11 rotates, it drives the stirring paddle 14 and the auxiliary dispersion disk 15 to rotate together. Several through holes 16 with a diameter of 3mm to 5mm are opened on the surface of the stirring paddle 14. During the rotation of the stirring paddle 14, the solution will form convection on the upper and lower sides of the stirring paddle 14 through the through holes 16, which increases the degree of mixing of the solution and allows the potassium nitrate in the solution to cool and crystallize more evenly. When the auxiliary dispersion disk 15 rotates, the solution will be dispersed into multiple fine liquid streams by the diversion holes 17, further improving the mixing effect of the solution and promoting the growth and uniform distribution of potassium nitrate crystals.

[0027] As the solution temperature decreases, potassium nitrate crystals gradually adhere to the inner wall of tank 1 and the outer wall of heat exchange tube 9. To prevent excessive crystal adhesion and scaling, which could affect the normal operation and heat exchange efficiency of the device, the anti-scaling scraping mechanism 4 is activated. The drive motor 13 drives the rotating shaft 11 to rotate, which in turn drives the scraper 12 to rotate. The scraper 12 has a wear-resistant rubber layer with a thickness of 2mm to 3mm. The wear-resistant rubber layer is in close contact with the inner wall of tank 1 and the outer wall of heat exchange tube 9. During the rotation of the scraper 12, the wear-resistant rubber layer continuously scrapes the inner wall of tank 1 and the outer wall of heat exchange tube 9, scraping off the potassium nitrate crystals adhering to them and allowing them to return to the solution to continue participating in the crystallization process, thereby effectively preventing scaling.

[0028] When the potassium nitrate crystals in the solution reach a certain level, the crystallized potassium nitrate needs to be discharged from tank 1. At this time, the discharge assembly 5 starts to work, and the vibration generated by the vibrator 19 is transmitted to the discharge pipe 18, so that the potassium nitrate crystals in the discharge pipe 18 can be discharged more smoothly. Since the bottom of the tank 1 is provided with a conical guide section 6, which is coaxially arranged with the tank 1 and has a cone angle range of 120° to 150°, under the action of gravity, the potassium nitrate crystals in the tank will flow along the surface of the conical guide section 6 to the discharge port, and then be discharged from the tank 1 through the discharge pipe 18. In addition, the surface of the conical guide section 6 is coated with a 0.2 mm to 0.5 mm thick anti-scaling coating made of polytetrafluoroethylene. Polytetrafluoroethylene has good corrosion resistance and non-stick properties, which can further prevent potassium nitrate crystals from adhering and scaling on the surface of the conical guide section 6, ensuring smooth discharge.

[0029] Throughout the operation, all components work together to achieve efficient potassium nitrate crystallization. The heat exchange tube group 2, with its increased heat exchange area through fins 10, significantly improves cooling efficiency, solving the problems of low heat exchange efficiency and uneven cooling in traditional jacketed heat exchange methods. The design of the scraper 12 and wear-resistant rubber layer in the anti-scaling scraping mechanism 4 not only removes crystals from the inner wall of the tank 1 but also avoids stress concentration caused by temperature differences. The through holes 16 and diversion holes 17 in the stirring assembly 3 enhance liquid flowability and reduce the generation of local supercooled areas, thereby inhibiting excessive crystal aggregation. The conical guide section 6, combined with the application of the anti-scaling coating, greatly reduces the possibility of bottom deposition, while the vibrator 19 in the discharge assembly 5 solves the problem of discharge port blockage.

[0030] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although the utility model has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of this utility model.

Claims

1. A potassium nitrate crystallization apparatus, characterized in that: The potassium nitrate crystallization device includes a tank (1), a heat exchange tube assembly (2), a stirring assembly (3), an anti-scaling and wall-scraping mechanism (4), and a discharge assembly (5). The tank (1) has a hollow internal structure with an inlet at the top and an outlet at the center of the bottom. The bottom of the tank (1) is provided with a conical guide section (6). The heat exchange tube assembly (2) includes multiple vertically arranged heat exchange tubes (9). The outer wall of the heat exchange tubes (9) is provided with fins (10). The heat exchange tubes (9) penetrate the top wall of the tank (1) and extend into the inner cavity of the tank (1). They are evenly distributed along the circumference of the top wall. One end is connected to an external cooling system through a cooling medium input pipe, and the other end is connected to the cooling medium. The quality output pipe is connected, and the stirring assembly (3) includes a stirring paddle (14) and an auxiliary dispersion disc (15), both of which are installed on the rotating shaft (11). The anti-scaling scraping mechanism (4) includes a rotating shaft (11), multiple scrapers (12) and a drive motor (13). The rotating shaft (11) passes through the top wall of the tank (1) and extends to the inner cavity of the tank (1). The scrapers (12) are evenly distributed along the outer wall of the rotating shaft (11). The discharge assembly (5) includes a discharge pipe (18) and a vibrator (19). The discharge pipe (18) is fixed at the discharge port at the center of the bottom surface of the tank (1). The vibrator (19) is fixed to the outer wall of the conical guide section (6) by bolts.

2. The potassium nitrate crystallization apparatus as described in claim 1, characterized in that: The surface of the stirring paddle (14) has several through holes (16) with a diameter of 3 mm to 5 mm. The surface of the auxiliary dispersion disk (15) has several diversion holes (17) with a diameter of 3 mm to 5 mm. The diversion holes (17) are evenly distributed around the bottom surface of the auxiliary dispersion disk (15).

3. The potassium nitrate crystallization apparatus as described in claim 2, characterized in that: The scraper (12) is evenly distributed along the outer wall of the rotating shaft (11), and the scraper (12) is provided with a wear-resistant rubber layer with a thickness of 2mm to 3mm.

4. A potassium nitrate crystallization apparatus as described in claim 1 or 2, characterized in that: The conical guide section (6) is coaxially arranged with the tank body (1) and the cone angle ranges from 120° to 150°. The surface of the conical guide section (6) is coated with a scale-resistant coating with a thickness of 0.2 mm to 0.5 mm, and the material is polytetrafluoroethylene.

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