High-tower granulation device for sodium nitrate

Abstract

The utility model relates to a high-tower granulation device for sodium nitrate. The high-tower granulation device comprises a granulation tower, a spraying device is arranged at the upper part inside the prilling tower; a gas inlet pipe is arranged at the bottom of the granulation tower side wall; an exhaust fan is arranged at the top of the granulation tower; a hot air pipe is arranged on the side wall of the granulation tower and is used for conveying hot air into the tower. By increasing backflow air and reducing the cooling speed in the initial cooling process, cracks on the surfaces of the particles can be reduced, and the hardness and the granulation rate of the particles are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of granulation, in particular to a sodium nitrate high-tower granulation device. Background Art

[0002] At present, the granulation of sodium nitrate is generally carried out using a granulation tower. The principle is that the sodium nitrate raw material is heated to melt, and the liquid sodium nitrate is pumped to the injection device at the top of the granulation tower. The injection device sprays the liquid sodium nitrate to form droplets or mist droplets. The sprayed droplets fall from the inside of the high tower, and the external air enters from the bottom of the high tower and rises, and is discharged from the top of the tower. In this way, the sodium nitrate droplets will perform countercurrent heat exchange with the rising air during the falling process, and the droplets condense to form particles and fall to the bottom of the tower, and then are collected and packaged;

[0003] At present, in the above process, due to the large temperature difference between the external air and the sodium nitrate droplets, the external temperature of the droplets cools down too quickly during the droplet falling process. The large temperature difference can easily cause particle cracking, reduce the granulation rate and particle hardness. Utility Model Content

[0004] In order to solve the problems existing in the above-mentioned technology, the utility model provides a 1. sodium nitrate high tower granulation device, characterized in that it comprises a granulation tower;

[0005] A spray device is arranged at the upper inner part of the granulation tower;

[0006] An air inlet pipe is arranged at the bottom of the side wall of the granulation tower;

[0007] An exhaust fan is arranged on the top of the granulation tower;

[0008] A hot air pipe is arranged on the side wall of the granulation tower for conveying hot air into the tower.

[0009] It also includes a return fan, which is used to transport the gas that has undergone countercurrent heat exchange into the tower through the hot gas pipe.

[0010] Wherein, the spray device is a spray cup.

[0011] Wherein, an interlayer is arranged in the side wall of the granulation tower, a cold source passes through the interlayer, and the cold energy of the cold source can be conducted to the inner wall of the granulation tower;

[0012] A scraping device is arranged in the granulation tower, and the scraping device is used to scrape the inner wall of the granulation tower.

[0013] Wherein, the scraping device is a scraping ring, the outer side wall of the scraping ring is adjacent to the inner side wall of the granulation tower, and the scraping ring can move vertically.

[0014] Wherein, a molten salt tank is arranged above the granulation tower.

[0015] Wherein, a circulation pump is arranged in the molten salt tank.

[0016] Wherein, a rotating disk is arranged on the bottom surface of the granulation tower.

[0017] Wherein, an air filter is arranged on the top of the granulation tower.

[0018] The beneficial effects of the utility model are:

[0019] 1. Increase the reflux air and reduce the cooling rate during the initial cooling process, which can reduce cracking on the particle surface and improve particle hardness and granulation rate.

[0020] 2. The rotating spray cup can be used to adjust the particle size by controlling the rotation speed of the spray cup. The higher the speed, the smaller the particle size; the lower the speed, the larger the particle size;

[0021] 3. Set up an interlayer to cool the inner wall to facilitate scraping and recycling of attached materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] Figure 1 It is a schematic diagram of a granulation tower of the utility model;

[0024] Figure 2 It is a schematic diagram of the sodium nitrate high tower granulation equipment of the utility model;

[0025] Figure 3 It is a top view of the scraping ring of the utility model;

[0026] Figure 4 It is a three-dimensional diagram of the rotary disk of the utility model;

[0027] Figure 5 It is a stereoscopic diagram of the turntable of the utility model from another viewing angle.

[0028] Description of Reference Numerals

[0029] 1. The first elevator;

[0030] 2. Molten salt tank, 21. Circulation pump;

[0031] 3. Granulating tower, 301. Air filter, 302. Exhaust fan, 31. Interlayer, 311. Heat conducting layer, 312. Cooling fan, 32. Air inlet pipe, 33. Middle tank, 331. Spray cup, 34. Return fan, 35. Scraping ring, 351. Cylinder, 36. Ventilation port, 37. Bracket;

[0032] 4. rotary disc, 41. disc body, 411. first discharge port, 42. rotating rod, 43. annular groove, 431. scraper, 432. second discharge port, 433. discharge pipe, 434. annular plate, 44. sieve plate, 45. vibration motor, 46. connecting rod, 461. spring, 47. belt conveyor, 48. conical cap, 49. inclined rod;

[0033] 5. Second elevator;

[0034] 6. Cooling heat exchanger;

[0035] 7. Screening machine;

[0036] 8. The third elevator;

[0037] 9. Silo. DETAILED DESCRIPTION

[0038] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0039] like Figure 2 As shown, a sodium nitrate high tower granulation complete set of equipment using the sodium nitrate high tower granulation device of the present application is used, and the equipment includes a first elevator 1, a molten salt tank 2, a granulation tower 3, a second elevator 5, a cooling heat exchanger 6, a screening machine 7, a third elevator 8 and a silo 9 connected in sequence;

[0040] Among them, the multiple elevators, the molten salt tank 2, the cooling heat exchanger 6, the screening machine 7 and the silo 9 are all existing technologies.

[0041] like Figure 1 As shown, a middle groove 33 is provided at the upper inner part of the granulation tower 3, and the middle groove 33 is fixed by a bracket 37. The spray device can be a spray cup 331 in the prior art, which is provided below the middle groove 33, and the spray cup 331 is driven to rotate by a motor;

[0042] An air inlet pipe 32 is provided at the bottom of the side wall of the granulation tower 3;

[0043] A fan 302 and an air filter 301 are provided on the top of the granulation tower 3;

[0044] A hot air pipe is arranged on the side wall of the granulation tower 3, and a return fan 34 is arranged outside the granulation tower 3. The return fan 34 is used to transport the gas above the spray cup 331 that has undergone countercurrent heat exchange to the tower through the hot air pipe.

[0045] An interlayer 31 is arranged in the side wall of the granulation tower 3, and a cold source passes through the interlayer 31, and the cold energy of the cold source can be conducted to the inner wall of the granulation tower 3;

[0046] Specifically, the interlayer 31 has an air inlet and an air outlet, the air inlet is connected to the cooling fan 312 arranged outside the granulation tower 3, the inner wall of the interlayer 31 is a heat-conducting layer 311, and the heat-conducting layer 311 can be optionally made of copper and serves as a part of the inner wall of the granulation tower 3. The external air serving as a cold source can cool the heat-conducting layer 311 when passing through the interlayer 31.

[0047] A scraping device is provided in the granulation tower 3, and the scraping device is used to scrape the inner wall of the granulation tower 3;

[0048] like Figure 3 As shown, the scraping device is a scraping ring 35, the outer wall of the scraping ring 35 is adjacent to the inner wall of the granulation tower 3, a plurality of cylinders 351 are arranged above the bracket 37, and the cylinder rods of the cylinders 351 are fixedly connected to the top surface of the scraping tube 35;

[0049] The bottom discharge of the granulation tower 3 is as follows: Figure 1 , Figure 4 and Figure 5 As shown, the bottom of the granulation tower 3 is a rotating disk 4 as a material receiving and discharging device, and the rotating disk 4 includes a disk body 41, and a rotating motor is arranged at the center of the bottom circle of the disk body 41. The output shaft of the rotating motor vertically passes through the disk body 41, and a conical cap 48 is arranged on the top of the output shaft;

[0050] Two first strip-shaped material discharge openings 411 are provided on the disc body 41 . The two first material discharge openings 411 are respectively located on both sides of the output shaft, and the two first material discharge openings 411 are located on the same diameter of the disc body 41 .

[0051] At least one rotating rod 42 is disposed above the disk body 41 , the bottom of the rotating rod 42 is adjacent to the top surface of the disk body 41 , and the inclined rod 49 is parallel to and adjacent to the inner side wall of the annular plate 434 ;

[0052] An annular groove 43 is sleeved on the outside of the disc body 41, and the outer wall of the annular groove 43 is connected to the inner wall of the granulation tower 3. The annular groove 43 is higher than the height of the disc body 41. The annular groove 43 is connected to the outer wall of the disc body 41 through a trumpet-shaped annular plate 434. A second discharge port 432 is provided at the bottom of the annular groove 43.

[0053] At least one horizontal rotating rod 42 is disposed above the disk body 41, the bottom of the rotating rod 42 is adjacent to the top surface of the disk body 41, and one end of the rotating rod 42 is fixedly connected to the output shaft of the rotary motor;

[0054] A belt conveyor 47 and an inclined screen plate 44 are arranged below the disc body 41. The lower end of the screen plate 44 is located above the belt conveyor 47. The conveying direction of the belt conveyor 47 is consistent with the extending direction of the first unloading port 411.

[0055] A feeding pipe 433 is provided at the bottom of the second feeding port 432. The bottom opening of the feeding pipe 433 is located above the sieve plate 44.

[0056] Specifically, the sieve plate 44 is connected to the bottom surface of the plate body 41 by a plurality of vertical connecting rods 46, and the connecting rod 46 is divided into two sections, and the two sections are connected by a spring 461;

[0057] A vibration motor 45 is disposed on the bottom surface of the sieve plate 44 , and a collection box is disposed below the sieve plate 44 .

[0058] The principle of the sodium nitrate high tower granulation device provided by the present application is explained below in combination with the overall process of sodium nitrate granulation:

[0059] 1. The sodium nitrate crystals are transported to the molten salt tank 2 through the first hoist 1. The molten salt tank 2 heats the crystals to melt and remove moisture through electric heating. The heating temperature is 310°C. The molten salt tank 2 is equipped with an electric heater and a circulation pump 21. The function of the circulation pump 21 is to circulate the sodium nitrate liquid in the molten salt tank 2, so as to avoid local overheating of the sodium nitrate molten salt.

[0060] 2. The molten salt pump in the molten salt tank 2 transports the melted sodium nitrate liquid to the intermediate tank 33;

[0061] The melted sodium nitrate liquid in the middle tank flows by gravity into the rotating spray cup 331;

[0062] 3. Use the spray cup 311 to spray the molten sodium nitrate liquid into the granulation tower 3, and the exhaust fan 302 continues to work, so that the external air enters the tower through the air inlet pipe 32 and rises, forming a cooling airflow;

[0063] The high-temperature molten sodium nitrate liquid flows out through the numerous small holes on the wall of the high-speed rotating spray cup 311 to form numerous droplets. The particle size can be adjusted by controlling the rotation speed of the spray cup. The higher the speed, the smaller the particle size; the lower the speed, the larger the particle size.

[0064] As the droplets fall, they cool from bottom to top and exchange heat with the high-temperature liquid, first cooling the surface of the droplets into a hard shell;

[0065] The high-temperature air after heat exchange is returned to the upper part of the granulation tower 3 by the return fan 34, and mixed with the rising air from the lower part, so as to avoid the droplets from cooling down too fast, and effectively control the formation speed of the hard shell and avoid the occurrence of cracking.

[0066] As the particles fall in the tower, they are constantly in contact with the strong cold air at the bottom for heat exchange. The liquid phase inside the small particles gradually cools and shrinks, solidifying into a solid phase. The droplets and the cold air are in reverse heat exchange. The cold air goes from bottom to top, and the temperature is rising. The droplets go from top to bottom, and the temperature is falling.

[0067] The hot air after heat exchange enters the air filter 301 through the vent 36 at the narrow section of the tower top, and is extracted from the tower top by the exhaust fan 302 after being filtered.

[0068] 4. Since some of the droplets thrown out of the spray cup 311 may be thrown to the upper part of the inner wall of the granulation tower 3 before forming a sufficiently thick shell, if not treated, this part of the liquid will slowly cool down on the upper part of the inner wall of the granulation tower 3 to form a relatively dense film layer, which is not easy to recover the raw materials. Therefore, during the granulation process, a cold source is introduced into the interlayer 31 to cool down the inner wall of the granulation tower 3 corresponding to the interlayer 31, so that the sodium nitrate particles hanging on the wall are quickly cooled and cracked, which is easy to remove;

[0069] The scraping ring 35 is driven by the cylinder 351 to scrape it;

[0070] 5. Most of the cooled solid particles fall onto the disk 41 and the annular plate 434 of the high tower, the scraped material and a small amount of particles fall into the annular groove 43, and the particles falling onto the conical cap 48 are also guided to the disk 41;

[0071] The shaft of the rotary motor drives the rotating rod 42, the inclined rod 49 and the scraper 431 to rotate;

[0072] The particles on the tray 41 are pushed and dropped onto the belt conveyor 47 through the first discharge port 411;

[0073] The scraped material in the scraper 431 falls onto the screen plate 44 through the second discharge port 432 and the discharge pipe 433, and the vibration motor 45 performs screening by vibration, and the sodium nitrate powder falls into the collection box, while the particles are transported to the belt conveyor 7;

[0074] 6. The belt conveyor 7 conveys the particles to the second elevator 5, and then to the cooling heat exchanger 6 for cooling. The cooled particles are screened by the screening machine 7, and the screened particles are conveyed to the silo 9 by the third elevator 8 and wait for packaging.

[0075] Collect, transport, screen and package sodium nitrate solid particles. Example 1

[0076] The tower is 45 meters high, the spray cup 331 is 40 meters high, the liquid sodium nitrate is 310℃, the spray droplet diameter is 1 mm, the hot air pipe is 35 meters high, the interlayer 31 extends from 30 meters to 40 meters high, the hot air pipe passes through the interlayer 31 and is insulated, the end face of the hot air pipe is flush with the inner wall of the granulation tower 3, the mixed air temperature at a height of 35 meters in the tower is 210℃, the temperature of the heat conductive layer 311 of the interlayer 31 close to the tower is 110℃, scraping is performed once a minute, a receiving container is set above the disc 41, and the sieving machine screens the particles, and the granulation rate is calculated based on the total weight of the particles to the total weight of the receiving materials = 92%, and the particle strength is measured to be 0.9-1.7kgf. After shutdown, the inner wall of the granulation tower 3 is visually inspected, and the inner wall is relatively smooth without obvious attachment. Example 2

[0077] The difference between this embodiment and embodiment 1 is that the mixed air temperature at a height of 35 meters in the tower is 200° C., the granulation rate is 90%, the granule strength is 0.8-1.5 kgf, and the inner wall of the granulation tower 3 is visually inspected after shutdown, and the inner wall is relatively smooth without obvious adhesion. Example 3

[0078] The difference between this embodiment and embodiment 1 is that the mixed air temperature at a height of 35 meters in the tower is 230°C, the granulation rate is 3%, the granule strength is 0.9-1.8kgf, and the inner wall of the granulation tower 3 is visually inspected after shutdown, and the inner wall is relatively smooth without obvious attachment.

[0079] Comparative Example 1

[0080] The difference between this comparative example and Example 1 is that the mixed air temperature at a height of 35 meters in the tower is 190° C., the granulation rate is 78%, and the granule strength is 0.5-1.4 kgf.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that the temperature of the side of the heat-conducting layer 311 of the interlayer 31 close to the inside of the tower is 120° C. After shutdown, a visual inspection of the inner wall of the granulation tower 3 shows that there are multiple spots attached on the heat-conducting layer 311 .

[0083] Comparative Example 3

[0084] The difference between this comparative example and Example 1 is that no hot air is added into the tower, the reflux fan 34 is stopped, the granulation rate is 61%, and the granule strength is 0.4-1.1 kgf.

[0085] Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Claims

1. A sodium nitrate high tower granulation device, characterized in that, Including prilling tower; A spray device is arranged at the upper inner part of the granulation tower; An air inlet pipe is arranged at the bottom of the side wall of the granulation tower; An exhaust fan is arranged on the top of the granulation tower; A hot air pipe is arranged on the side wall of the granulation tower for conveying hot air into the tower.

2. A sodium nitrate high tower granulation device according to claim 1, characterized in that, The granulation tower also includes a return fan, which is used to transport the gas that has undergone countercurrent heat exchange into the tower through the hot gas pipe.

3. A sodium nitrate high tower granulation device according to claim 1, characterized in that, The spray device is a spray cup.

4. A sodium nitrate high tower granulation device according to claim 1, characterized in that, An interlayer is arranged in the side wall of the granulation tower, a cold source passes through the interlayer, and the cold energy of the cold source can be conducted to the inner wall of the granulation tower; A scraping device is arranged in the granulation tower, and the scraping device is used to scrape the inner wall of the granulation tower.

5. A sodium nitrate high tower granulation device according to claim 4, characterized in that, The scraping device is a scraping ring, the outer side wall of the scraping ring is adjacent to the inner side wall of the granulation tower, and the scraping ring can move vertically.

6. A sodium nitrate high tower granulation device according to claim 4, characterized in that, A molten salt tank is arranged above the granulation tower.

7. A sodium nitrate high tower granulation device according to claim 6, characterized in that: A circulation pump is arranged in the molten salt tank.

8. A sodium nitrate high tower granulation device according to claim 6, characterized in that: A rotating disk is arranged on the bottom surface of the granulation tower.

9. A sodium nitrate high tower granulation device according to any one of claims 1 to 8, characterized in that: An air filter is arranged on the top of the granulation tower.

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