Compound fertilizer melt granulation device with multi-layer structure

Abstract

The compound fertilizer melt granulation device with a multi-layer structure disclosed by the present invention includes a hierarchical feeding mechanism and a multi-layer rotating granulation spray disc which are connected to each other; the multi-layer rotating granulation spray disc includes an annular upper end plate and a lower end plate, and a number of equally distributed indexing half-tubes with the same structure are vertically arranged between the upper end plate and the lower end plate. A rectangular spray opening is formed by a gap between every two indexing half-tubes. A number of intermediate partition plates are also horizontally arranged between the upper end plate and the lower end plate, and a number of indexing half-tubes are evenly distributed at the circumferential positions of a number of intermediate partition plates; a first through hole is opened at the center of each intermediate partition plate, and the upper end plate is connected to the hierarchical feeding mechanism. This device can increase the output of compound fertilizer melt granulation according to actual production requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering equipment, and particularly relates to a compound fertilizer melt granulation device with a multi-layer structure. Background Art

[0002] In the compound fertilizer melt granulation process of chemical fertilizers, first, the nitrogen-containing material (urea or ammonium nitrate) is melted, and then it is stirred with the phosphorus-containing powder material and potassium-containing powder material heated to the process temperature through a mixing device to form a flowable liquid composite slurry with a certain temperature. Then, the mixed slurry is dropped from the top of the granulation tower in the form of droplets through a special granulation nozzle. During the process of contacting and cooling with the countercurrent cooling medium air in the granulation tower, the droplets automatically shrink into spherical solid particles.

[0003] Traditional high tower compound fertilizer differential granulation nozzles are all spray blue with hole structures. As Figure 1-2 shown, thousands or even tens of thousands of small spray holes with a diameter of about 3 mm are opened on the generatrix surface of the spray blue cone of the granulation nozzle. The melt slurry is ejected from these small spray holes in the form of a liquid jet by the centrifugal force of the rotating granulation nozzle. Since the compound fertilizer melt slurry contains a considerable proportion of solid insoluble substances, its melt viscosity is thousands or even tens of thousands of times that of the urea melt viscosity. Therefore, the spray holes of the traditional high tower compound fertilizer differential granulation process are much larger than the diameter of the urea nozzle. Therefore, it is absolutely impossible to mass-produce small particle products with the spray holes for compound fertilizer granulation, and small diameter spray holes cannot adapt to the continuous production of high-viscosity melt due to the too small nozzle holes. At the same time, it is also very difficult to produce spherical compound fertilizer particles with a small diameter by the pelletizing method. This is a common understanding in the compound fertilizer industry. However, the agrochemical market has an urgent need for small particle compound fertilizers with a particle size of 1 mm. Such small particle compound fertilizers are the preferred option for high-value crops such as flowers and lawns, and there is a quite mature application market abroad. Therefore, it is also an inevitable supply and demand trend for Chinese agrochemical products. Especially, making high-concentration fully water-soluble compound fertilizers into mm-level small particles will better meet the requirements of rapid dissolution of water-soluble fertilizers. High-value products such as small particle fully water-soluble compound fertilizers have obvious complementary effects and commercial benefit advantages in the Chinese agrochemical market.

[0004] The invention patent 210910472907.0 discloses "an atomizing rotary spray disc for fertilizer production". This spray disc can eject the fertilizer composite melt in the form of misty droplets. The ejected melt contacts and fuses with the seed particles that need to grow by coating, gradually forming particles of the required volume. This granulation process is similar to the slurry granulation of large granular urea, and droplets of different volumes can be obtained by adjusting the rotation speed of the spray disc. This patented granulation spray disc is fully capable of handling the spraying volume in the process of contacting, fusing and growing by coating the ejected melt with the seed particles. However, if it is directly used to produce small granular compound fertilizer products, it cannot meet the requirements of large fertilizer production, because the single-layer structure it protects severely limits the number of spray outlets and the total cross-sectional area of the spray outlets. Agricultural fertilizers are low-value bulk commodities, and the enterprise profit can only be obtained from a sufficiently large production capacity. Therefore, producers attach great importance to and rely on the output of the device.

[0005] The only way to increase the spraying volume is to increase the number of spray outlets and the total cross-sectional area of the spray outlets. However, increasing the number of spray outlets requires increasing the diameter of the spray disc, and increasing the diameter of the spray disc will cause the molten liquid to directly spray onto the inner wall of a hollow circular or rectangular building, that is, similar to the sticky tower wall in tower granulation. In addition, increasing the cross-sectional area of the rectangular spray outlet will result in poor feeding uniformity of the rectangular spray outlet of the spray disc if the height of the outlet is too large, and the consequence will be that the uniformity of the particles exceeds the standard. Summary of the Invention

[0006] The purpose of the present invention is to provide a compound fertilizer melt granulation device with a multi-layer structure, which can increase the output of compound fertilizer melt granulation according to actual production requirements.

[0007] The technical solution adopted by the present invention is that a compound fertilizer melt granulation device with a multi-layer structure includes a layered feeding mechanism and a multi-layer rotary granulation spray disc that are connected to each other;

[0008] The multi-layer rotary granulation spray disc includes an annular upper end plate and a lower end plate. Vertically arranged between the upper end plate and the lower end plate are a number of equally distributed indexing half-tubes with the same structure. There is a gap between every two indexing half-tubes to form a rectangular spray outlet. Horizontally arranged between the upper end plate and the lower end plate are several intermediate partitions. A number of indexing half-tubes are evenly distributed on the circumferences of several intermediate partitions; a first through hole is opened at the center of each intermediate partition, and the upper end plate is connected to the layered feeding mechanism.

[0009] The features of the present invention also lie in that,

[0010] The layered feeding mechanism includes a connecting flange and a feeding box unit. The connecting flange is connected to the main shaft of the granulator, the lower end face of the connecting flange is connected to the feeding box unit, and the feeding box unit sequentially passes through the circular hole at the center of the upper end plate of the multi-layer rotary granulation spray disc and the first through holes of several intermediate partitions.

[0011] The feeding box unit includes an upper end plate of the feeding box with a second through hole at the center, an outer cylinder of the feeding box and an inner cylinder of the feeding box arranged in sequence from outside to inside. The outer cylinder of the feeding box and the inner cylinder of the feeding box are respectively welded to the lower end surface of the upper end plate of the feeding box. The inner diameter of the inner cylinder of the feeding box is the same as the inner diameter of the second through hole at the center of the upper end plate of the feeding box; a feeding elbow is also connected to the side wall of the outer cylinder of the feeding box; an annular convex block is also provided on the inner wall of the outer cylinder of the feeding box, and there is a gap between the annular convex block and the outer wall of the inner cylinder of the feeding box; a plurality of vertically arranged baffle plates are evenly welded radially on the outer wall of the inner cylinder of the feeding box corresponding to the lower part of the annular convex block. The total number of baffle plates is divisible by 3. The plurality of baffle plates are evenly divided into three feeding sectors with a single baffle plate as the dividing boundary. The number of baffle plates in each feeding sector is the same as the number of intermediate partitions of the multi-layer rotating granulation spray disc; a plurality of flow guiding tongue plates are also arranged in each feeding sector. Each flow guiding tongue plate is located between two baffle plates. The number of flow guiding tongue plates in each feeding sector is the same as the number of intermediate partitions of the multi-layer rotating granulation spray disc. The flow guiding tongue plates and the intermediate partitions are arranged in one-to-one correspondence. The installation height of each flow guiding tongue plate is different, and the installation height of each flow guiding tongue plate matches the corresponding intermediate partition. The lower edge of the flow guiding tongue plate is arranged above the corresponding intermediate partition; a plurality of vertically arranged baffle plates sequentially pass through the circular hole at the center of the upper end plate of the multi-layer rotating granulation spray disc and the first through holes of several layers of intermediate partitions.

[0012] The angle between the flow guiding tongue plate and the outer wall of the inner cylinder of the feeding box is 45° - 60°.

[0013] The number of intermediate partitions is 2 - 5 layers.

[0014] The outer diameter of the upper end plate and the lower end plate is 280mm - 450mm.

[0015] The indexing semi-tube is a concave support plate. The cross-section of the support plate is arc-shaped. The wall thickness of the indexing semi-tube is 5mm - 10mm; the outer circle of the indexing semi-tube is R30 - R45.

[0016] The number of indexing semi-tubes is 12 - 16.

[0017] The height of the rectangular nozzle is 25mm - 35mm, and the width is 6mm - 12mm.

[0018] The beneficial effects of the present invention are:

[0019] (1) The granulator that provides rotational power for the device of the present invention is a general direct-connected mechanical transmission electromechanical device without any technical barriers;

[0020] (2) The granulation process used in the device of the present invention follows the traditional melt granulation process. The phase change medium for the compound fertilizer spherical particles from liquid phase to solid phase is normal temperature air without any technical barriers.

[0021] (3) The granulation pulping process that provides the melt for the device of the present invention follows the traditional pulping process for high - tower compound fertilizer granulation. This process has been in large - scale industrial production for more than 20 years and has become quite mature through the continuous efforts of technicians in the industry, and there are no technical barriers either.

[0022] (4) Since the particle size of a single particle is very small, it is very easy to complete the phase change from liquid to solid. Therefore, there is no need for a traditional granulation tower with a chimney effect. Only a granulation workshop with a certain height and a circular or giant cross - sectional area of any structure is required, and there are no technical barriers either.

[0023] (5) The multi - layer rotating granulation spray disc designed in the device of the present invention changes the single - layer structure of the original invention patent 210910472907.0 to a multi - layer structure. The spraying amount of each layer will be twice that of the original invention patent. Assuming that the spraying amount of the original invention patent 210910472907.0 is 10 tons per hour, if this multi - layer structure spray disc has two layers, its spraying amount will be 20 tons per hour, and if it has three layers, its spraying amount will be 30 tons per hour, and so on. Since the end diameter of the spray holes of the granulation spray disc is not changed, the maximum spraying diameter of the melt jet will not be changed. That is to say, under the same melt spraying diameter, by only changing the number of layers of the spray disc, the output can be increased to 2 - 5 times. Since the height of the spray disc increases exponentially, if the melt still only returns from the bottom upwards, it will inevitably lead to uneven distribution of the melt liquid. In order to make the melt liquid amount of each layer consistent, the core of the present invention is to design a structure that supplies materials evenly to each layer of the spray disc, that is, a layered feeding mechanism. This mechanism can ensure that the melt receiving amount of each layer of the spray disc is the same, and only in this way can the uniformity of the finished product particles be ensured. The multi - layer rectangular - hole rotating granulation spray disc in the device of the present invention can meet the requirements for the sphericity, qualification rate, strength and large output of the finished product; the combination of the layered feeding mechanism of the present invention and the multi - layer spray disc can mass - produce mm - level high - viscosity small - particle ternary compound fertilizer.

[0024] (6) Except for the multi - layer rotating granulation spray disc in the device of the present invention, since other technologies are all mature technologies and processes that do not require intellectual property protection, there are obvious advantages in terms of promotion, investment and operation costs, etc. Description of the Drawings

[0025] Figure 1 is a schematic diagram of a traditional compound fertilizer granulation nozzle from one angle;

[0026] Figure 2 is a schematic diagram of a traditional compound fertilizer granulation nozzle from another angle;

[0027] Figure 3 is a structural cross - sectional view of the compound fertilizer melt granulation device with a multi - layer structure of the present invention;

[0028] Figure 4 is a schematic structural view of the hierarchical feeding mechanism in the present invention;

[0029] Figure 5 is a schematic structural view of the multi-layer rotating granulation spray disc in the present invention;

[0030] Figure 6 is a structural sectional view of the multi-layer rotating granulation spray disc in the present invention;

[0031] Figure 7 is a schematic structural view of the division of the hierarchical feeding area within a sector in the present invention.

[0032] In the figure, 1. connecting flange, 2. upper end plate of the feeding box, 3. outer cylinder of the feeding box, 4. inner cylinder of the feeding box, 5. annular convex block, 6. flow guiding tongue plate, 7. material dividing plate, 8. feeding elbow, 9. upper end plate, 10. intermediate partition plate, 11. indexing semi-tube, 12. lower end plate, 13. granulator housing, 14. lower bearing of the granulator, 15. main shaft of the granulator, 16. spray disc connecting shaft sleeve, 17. main shaft nut, 18. rectangular spray opening;

[0033] 2-1. second through hole, 10-1. first through hole;

[0034] A. first equal division area, B. second equal division area, C. third equal division area, D. fourth equal division area. Detailed implementation manners

[0035] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0036] The present invention provides a compound fertilizer melt granulation device with a multi-layer structure, as Figure 3-7 shown, which includes a hierarchical feeding mechanism and a multi-layer rotating granulation spray disc connected to each other;

[0037] The multi-layer rotating granulation spray disc includes a circular ring-shaped upper end plate 9 and a lower end plate 12. Vertically arranged between the upper end plate 9 and the lower end plate 12 are a number of equally distributed indexing semi-tubes 11 with the same structure. A gap is formed between every two indexing semi-tubes 11 to form a rectangular spray opening 18. Horizontally arranged between the upper end plate 9 and the lower end plate 12 are also a number of layers of intermediate partition plates 10. The multi-layer rotating granulation spray disc is internally divided into multiple independent cavities with the same volume by the number of layers of intermediate partition plates 10. The height of each independent cavity is the same,

[0038] A number of indexing half pipes 11 are evenly distributed at the circumferential positions of a number of intermediate partitions 10; a first through hole 10-1 is provided at the center of each intermediate partition 10. The upper end plate 9 is connected to the layered feeding mechanism, and the center circular hole of the upper end plate 9 is the molten liquid inlet. The molten liquid enters the inside of the multi-layer rotary granulation spray disc by its own weight through the feeding box unit of the layered feeding mechanism of the granulator. The lower end plate 12 is connected to the main shaft 15 of the granulator through a spray disc connecting bushing 16, and a main shaft nut 17 is installed at the bottom of the main shaft 15 of the granulator.

[0039] The number of intermediate partitions 10 determines the number of layers of the multi-layer rotary granulation spray disc. The upper end plate 9, the lower end plate 12, a number of indexing half pipes 11 and a number of intermediate partitions 10 form an integral spray disc by means of metal welding.

[0040] The layered feeding mechanism includes a connecting flange 1 and a feeding box unit. A lower bearing 14 of the granulator is also sleeved on the main shaft 15 of the granulator. The connecting flange 1 is located below the lower bearing 14 of the granulator. The main shaft 15 of the granulator and the lower bearing 14 of the granulator are located inside the granulator housing 13. The connecting flange 1 is connected to the main shaft 15 of the granulator. The connecting flange 1 is sleeved on the main shaft 15 of the granulator. The lower end surface of the connecting flange 1 is connected to the feeding box unit. The feeding box unit sequentially passes through the circular hole at the center of the upper end plate 9 of the multi-layer rotary granulation spray disc and the first through hole 10-1 of a number of intermediate partitions 10.

[0041] The feeding box unit has the function of layered and equal feeding. The feeding box unit includes an upper end plate 2 of the feeding box with a second through hole at the center, a feeding box outer cylinder 3 and a feeding box inner cylinder 4 arranged in sequence from outside to inside. The feeding box outer cylinder 3 and the feeding box inner cylinder 4 are respectively welded to the lower end face of the upper end plate 2 of the feeding box. The inner diameter of the feeding box inner cylinder 4 is the same as the inner diameter of the second through hole 2-1 at the center of the upper end plate 2 of the feeding box; a feeding elbow 8 is also connected to the side wall of the feeding box outer cylinder 3; an annular convex block 5 is also provided on the inner wall of the feeding box outer cylinder 3, and there is a gap between the annular convex block 5 and the feeding box inner cylinder 4; a plurality of vertically arranged baffle plates 7 are evenly welded radially on the outer wall of the feeding box inner cylinder 4 corresponding to the lower part of the annular convex block 5. The total number of the baffle plates 7 is divisible by 3. The plurality of baffle plates 7 are evenly divided into three feeding sectors with a single baffle plate 7 as the dividing boundary. The number of baffle plates 7 in each feeding sector is the same as the number of layers of the intermediate partition 10 of the multi-layer rotary granulation spray disc; a plurality of flow guiding tongue plates 6 are also arranged in each feeding sector. Each flow guiding tongue plate 6 is located between two baffle plates 7. The number of flow guiding tongue plates 6 in each feeding sector is the same as the number of layers of the intermediate partition 10 of the multi-layer rotary granulation spray disc. The flow guiding tongue plates 6 and the intermediate partition 10 are arranged in one-to-one correspondence. The installation height of each flow guiding tongue plate 6 is different. The installation height of each flow guiding tongue plate 6 matches the corresponding intermediate partition 10. The lower edge of the flow guiding tongue plate 6 is arranged above the corresponding intermediate partition 10. The melt respectively falls onto the upper end face of the intermediate partition 10 of the rotary spray disc through the inclined angle of the flow guiding tongue plate 6 and is ejected from the rectangular outlet 18 of the spray disc by the rotational centrifugal force; a plurality of vertically arranged baffle plates 7 sequentially pass through the circular hole at the center of the upper end plate 9 of the multi-layer rotary granulation spray disc and the first through hole 10-1 of several layers of intermediate partitions 10. The connecting flange 1 is concentric with the feeding box outer cylinder 3, the feeding box inner cylinder 4 and the upper end plate 2 of the feeding box.

[0042] The molten liquid enters the cavity between the feeding box outer cylinder 3 and the feeding box inner cylinder 4 through the feeding elbow 8, enters the open groove evenly formed by a plurality of baffle plates 7 through the constriction formed by the annular convex block 5, and flows downward along the baffle plates 7 by its own weight. When the molten liquid descends, it encounters the flow guiding tongue plate 6 with an inclined angle and changes its direction, and flows into the upper part of the corresponding intermediate partition 10. The number of layers of layered feeding in each sector of the feeding box unit is consistent with the number of layers of the spray disc. The feeding melt of each layer falls equally on the corresponding layer plate of the rotary spray disc, and the feeding amount of the melt of each layer is equal.

[0043] The angle between the flow guiding tongue plate 6 and the outer wall of the feeding box inner cylinder 4 is 45° - 60°.

[0044] The number of layers of the intermediate partition 10 is 2 - 5 layers.

[0045] The outer diameters of the upper end plate 9 and the lower end plate 12 are 280mm - 450mm.

[0046] The indexing semi-tube 11 is a concave support plate, and the cross-section of the support plate is arc-shaped. The wall thickness of the indexing semi-tube 11 with an arc-shaped structure is 5 mm to 10 mm; the outer circle of the indexing semi-tube with an arc-shaped structure is R30 to R45, and the center of its arc is at the outer edge of the spray disc, and the arc surface faces the axis of the nozzle. The length of the indexing semi-tube 11 with an arc-shaped structure varies according to the number of layers of the multi-layer spray disc, and its total length is the height of each layer of the spray disc multiplied by the number of independent cavities.

[0047] The number of indexing semi-tubes 11 is 12 to 16.

[0048] The height of the rectangular nozzle 18 is 25 mm to 35 mm, and the width is 6 mm to 12 mm.

[0049] Taking a 4-layer spray disc as an example, for the sake of illustration, the indexing semi-tube 11 with an arc-shaped structure is hidden in this schematic diagram, and only several layers of intermediate partitions 10 are left.

[0050] On the outer wall of the inner cylinder 4 of the feed box, 12 distribution plates 7 are evenly welded radially. The 12 distribution plates 7 are divided into three feed sectors. Each feed sector is divided into four equal parts of the same first equal division area A, second equal division area B, third equal division area C, and fourth equal division area D. The flow guide tongue plates 6 are respectively welded between two distribution plates 7. The installation position of the flow guide tongue plate 6 at the first equal division area A corresponds to the first layer of intermediate partition 10 of the spray disc. The installation position of the flow guide tongue plate 6 at the second equal division area B corresponds to the second layer of intermediate partition 10 of the spray disc. The horizontal position of the flow guide tongue plate 6 at the third equal division area C corresponds to the third layer of intermediate partition 10 of the spray disc. There is no need to weld the flow guide tongue plate 6 at the fourth equal division area D. The melt directly falls onto the end face of the lower end plate 12. The melt falls onto the end faces of the corresponding intermediate partitions 10 in equal amounts by the inclination angle of the flow guide tongue plate 6 due to its own weight, and is ejected from the rectangular outlet 18 of the spray disc by rotational centrifugal force.

[0051] The granulation formation mechanism of the traditional melt granulation nozzle is that the melt is ejected in the form of a liquid flow through small holes and then breaks into liquid droplets of a certain volume. However, the multi-layer rotating granulation spray disc in the device of the present invention has no hole structure. The melt is ejected in the form of a liquid film from the tangent direction of the end points of the multi-layer N uniformly distributed rectangular outlet surfaces to form small liquid droplets. The particle formation mechanism of this multi-layer rotating granulation spray disc is that the melt liquid film is torn into liquid droplets of a certain volume by centrifugal force, and the liquid droplets are in contact with the countercurrent air in the granulation tower during the falling process for heat exchange until they shrink and solidify into spherical solid particles.

[0052] Agricultural chemical fertilizers are a kind of commodity with low added value, and their output determines the profit of enterprises. Therefore, manufacturers rely heavily on output. The multi-layer rotating granulation spray disc of the device of the present invention has an output that increases with the increase in the number of layers of the spray disc. If the spraying amount per layer is 10 tons, the spraying amount of the multi-layer spray disc with a 2-layer structure will be 20 tons per hour, and the spraying amount of the multi-layer spray disc with a 3-layer structure will be 30 tons per hour, and so on. Its characteristic is that since the end diameter of the spray orifice of the granulation spray disc is not changed, the maximum spraying diameter of the melt jet will not be changed. That is to say, under the same melt spraying diameter, by only changing the number of layers of the spray disc, the output can be increased to 2 to 5 times.

[0053] The device of the present invention also designs a hierarchical feeding mechanism for evenly feeding each layer of the spray disc. The purpose is to make the melt liquid volume of each layer consistent. This hierarchical feeding mechanism can ensure that the melt receiving amount of each layer of the spray disc is consistent. Only in this way can the uniformity of the finished product particles be ensured. The combination of the hierarchical feeding mechanism and the multi-layer spray disc can mass-produce small-particle ternary compound fertilizers with high viscosity at the millimeter level. The granulation spray disc can change the maximum diameter of the droplet spraying by adjusting the rotation speed of the main shaft of the granulator, and can change the thickness of the liquid film by adjusting the rotation speed of the main shaft and the melt feeding amount, and use the thickness of the liquid film to control the volume of the droplet, that is, the ball diameter of the particle.

Claims

1. The compound fertilizer melt granulation device with a multi-layer structure is characterized in that, It includes a hierarchical feeding mechanism and a multi-layer rotating granulation spraying disc that are connected to each other; The multi-layer rotating granulation spraying disc includes an annular upper end plate (9) and a lower end plate (12). Vertically arranged between the upper end plate (9) and the lower end plate (12) are a number of equally distributed indexing half-tubes (11) with the same structure. A rectangular spraying orifice (18) is formed by a gap between every two indexing half-tubes (11). Horizontally arranged between the upper end plate (9) and the lower end plate (12) are also several layers of intermediate partition plates (10). The number of indexing half-tubes (11) is evenly distributed around the circumference of the several layers of intermediate partition plates (10); a first through-hole (10-1) is opened at the center of each intermediate partition plate (10), and the upper end plate (9) is connected to the hierarchical feeding mechanism; The hierarchical feeding mechanism includes a connecting flange (1) and a feeding box unit. The connecting flange (1) is connected to the main shaft (15) of the granulator. The lower end face of the connecting flange (1) is connected to the feeding box unit. The feeding box unit sequentially passes through the circular hole at the center of the upper end plate (9) of the multi-layer rotating granulation spraying disc and the first through-holes (10-1) of the several layers of intermediate partition plates (10); The feeding box unit includes a feeding box upper end plate (2) with a second through-hole (2-1) at the center, a feeding box outer cylinder (3) and a feeding box inner cylinder (4) arranged in sequence from outside to inside. The feeding box outer cylinder (3) and the feeding box inner cylinder (4) are respectively welded to the lower end face of the feeding box upper end plate (2). The inner diameter of the feeding box inner cylinder (4) is the same as the inner diameter of the second through-hole (2-1) at the center of the feeding box upper end plate (2); a feeding elbow (8) is also connected to the side wall of the feeding box outer cylinder (3); an annular convex block (5) is also provided on the inner wall of the feeding box outer cylinder (3). There is a gap between the annular convex block (5) and the outer wall of the feeding box inner cylinder (4); radially and evenly welded on the outer wall of the feeding box inner cylinder (4) below the annular convex block (5) are a number of vertically arranged distributing plates (7). The total number of distributing plates (7) is divisible by 3. The several distributing plates (7) are evenly divided into three feeding sectors with a single distributing plate (7) as the dividing boundary. The number of distributing plates (7) in each feeding sector is the same as the number of layers of the intermediate partition plates (10) of the multi-layer rotating granulation spraying disc; several flow guiding tongue plates (6) are also provided in each feeding sector. Each flow guiding tongue plate (6) is located between two distributing plates (7). The number of flow guiding tongue plates (6) in each feeding sector is the same as the number of layers of the intermediate partition plates (10) of the multi-layer rotating granulation spraying disc. The flow guiding tongue plates (6) are arranged in one-to-one correspondence with the intermediate partition plates (10). The installation height of each flow guiding tongue plate (6) is different. The installation height of each flow guiding tongue plate (6) matches the corresponding intermediate partition plate (10). The lower edge of the flow guiding tongue plate (6) is arranged above the corresponding intermediate partition plate (10); the several vertically arranged distributing plates (7) sequentially pass through the circular hole at the center of the upper end plate (9) of the multi-layer rotating granulation spraying disc and the first through-holes (10-1) of the several layers of intermediate partition plates (10).

2. The compound fertilizer melt granulation device with a multi-layer structure according to claim 1, is characterized in that, The angle between the flow guiding tongue plate (6) and the outer wall of the feeding box inner cylinder (4) is 45°-60°.

3. The compound fertilizer melt granulation device with a multi-layer structure according to claim 1, is characterized in that, The number of layers of the middle partition plate (10) is 2 to 5 layers.

4. The compound fertilizer melt granulation device with a multi-layer structure according to claim 1, is characterized in that, The outer diameters of the upper end plate (9) and the lower end plate (12) are 280 mm to 450 mm.

5. The compound fertilizer melt granulation device with a multi-layer structure according to claim 1, is characterized in that, The indexing semi-tube (11) is a concave support plate, the cross-section of the support plate is arc-shaped, the wall thickness of the indexing semi-tube (11) is 5 mm to 10 mm; the outer circle of the indexing semi-tube is R30 to R45.

6. The compound fertilizer melt granulation device with a multi-layer structure according to claim 1, is characterized in that, The number of the indexing semi-tubes (11) is 12 to 16.

7. The compound fertilizer melt granulation device with a multi-layer structure according to claim 1, is characterized in that, The height of the rectangular nozzle (18) is 25 mm to 35 mm, and the width is 6 mm to 12 mm.

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