High-efficiency energy-saving pulping equipment for high-tower melt granulation of compound fertilizer

Abstract

The application discloses a kind of high-efficiency energy-saving pulping equipment for compound fertilizer high tower melting granulation, belong to fertilizer manufacturing equipment field.The equipment includes tank, overflow discharge port and stirring device, wherein overflow discharge port is equipped with adjustable overflow sleeve, longitudinal grid strip overflow hole group of axially arranged is opened in its sleeve wall, outer sleeve is driven to move up and down by lifting adjusting mechanism to selectively shield or open overflow hole group of different height;Lifting adjusting mechanism is also connected with stirring shaft, while driving outer sleeve to move, stirring blade is simultaneously driven to lift.The application is also equipped with flow guide cylinder with turbulence baffle and reverse baffle group at bottom end.The application realizes the accurate control of liquid level and the efficient mixing of slurry by the linkage adjustment of overflow liquid level and stirring position, combined with multiple turbulence structure in flow guide cylinder, significantly improves the homogeneity of slurry, reduces energy consumption, and enhances the adaptability to different working conditions.

Description

Technical Field

[0001] This invention relates to the field of fertilizer manufacturing equipment, specifically to a high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer. Background Technology

[0002] High-tower melt granulation technology for compound fertilizers, as a modern advanced fertilizer production technology, has gradually become the mainstream technology choice for newly built production lines in the domestic compound fertilizer industry due to its significant advantages such as large-scale production, stable product quality, relatively low energy consumption, and comprehensive product range. In the overall process of high-tower melt granulation, the pulping stage serves as the core bridge connecting raw material pretreatment and granulation. Its technical performance directly determines whether subsequent granulation processes can proceed smoothly and the nutrient uniformity and particle characteristics of the final product.

[0003] The production principle of high-tower melt granulation utilizes the property that molten urea, ammonium nitrate, monoammonium phosphate, potassium chloride, potassium sulfate, and other raw materials can form low-melting-point compounds. Powdered monoammonium phosphate, potassium chloride, potassium sulfate, and additives are metered and added to the molten, highly fluid NPK eutectic, and then sprayed into the compound fertilizer granulation tower through a specialized nozzle. Within the tower, the mixture cools and solidifies into granules in rising air, resulting in a compound fertilizer with uniform nutrients and good granular properties. In this principle, the task of the pulping stage is to thoroughly mix various solid raw materials with the molten carrier to form a homogeneous, flowable slurry, which is then conveyed to the top of the granulation tower for spraying and shaping. Therefore, the performance of the pulping equipment directly affects the homogeneity, flow characteristics, and temperature retention of the slurry, thus influencing the efficiency and product quality of the entire granulation process.

[0004] In terms of existing pulping equipment, its basic structure typically includes a melting tank, a primary mixing tank, and a secondary mixing tank, each equipped with a stirring device and a heating device. The stirring device generally consists of a drive motor, a stirring shaft, and impellers, using the rotation of the impellers to drive the molten material within the tank to generate a circulating flow. The heating device often employs jacketed heating or internal coil heating, transferring heat to the molten material within the tank through a heat transfer medium to maintain its required flow temperature. For material discharge, each tank typically has an overflow outlet at a fixed height on its side wall. When the liquid level in the tank rises to the overflow outlet, the pulp automatically flows out through this outlet and enters the next stage tank or is directly sent to the granulation system. This scheme, relying on a fixed overflow outlet for liquid level control, did indeed meet basic production needs in the early stages of pulping technology development; its design principle is relatively simple, and the equipment manufacturing cost is relatively controllable.

[0005] However, with the continuous development of high-tower melting granulation technology towards larger scale and finer processes, and the increasing demands on the quality of compound fertilizer products, the inherent design characteristics of existing pulping equipment at the principle level are gradually revealing deep-seated technical limitations when facing higher performance requirements. Specifically, traditional overflow devices use a fixed overflow port height design, and liquid level control depends entirely on the location of the overflow port. This rigid design cannot be dynamically adjusted according to changes in operating conditions. Once fluctuations occur in the raw material ratio, heating power, or discharge flow rate during production, the liquid level in the tank will fluctuate accordingly. These unexpected changes in liquid level will then have a chain reaction effect on mixing conditions, leading to fluctuations in slurry quality. Further analysis reveals that this fixed overflow port design essentially couples liquid level control with the overflow process, lacking flexible adjustment methods. This not only affects the stability of slurry homogeneity but also limits the adaptability of pulping equipment to a wider range of operating conditions.

[0006] In terms of mixing systems, the installation position of the agitator blades in existing technologies is usually fixed and cannot be adjusted according to changes in the liquid level in the tank or the requirements of the operating conditions. The axial installation position of the agitator blades directly determines the flow field distribution of the melt within their effective range. When the liquid level is low, the fixed-position blades may not be able to effectively cover the entire liquid surface height, resulting in insufficient mixing in the upper region. Conversely, when the liquid level is high, the mixing effect of the blades may be concentrated in the middle and lower regions, making the temperature and concentration fields of the upper melt less uniform. In addition, the flow patterns generated by traditional mixing systems are relatively simple, and the mixing mode driven by agitator blades has certain limitations in the mixing effect of high-viscosity melts, especially in applications requiring rapid homogenization and reduction of local concentration gradients, where the mixing efficiency often fails to meet higher process requirements. Correspondingly, due to the lack of a coordinated matching mechanism between the mixing position and the overflow port, a mismatch between the mixing intensity and the overflow position may occur under certain operating conditions. This not only reduces the mixing efficiency but may also cause unnecessary increases in energy consumption.

[0007] In summary, given the technological limitations of existing pulping equipment, the pulping stage of the high-tower melt granulation process for compound fertilizer still faces prominent problems such as the need to improve mixing efficiency, fluctuations in pulp homogeneity, and persistently high energy consumption. These technical contradictions not only restrict further breakthroughs in the technical performance of the pulping equipment itself but also, to some extent, affect the progress of the entire high-tower melt granulation process towards higher quality and higher efficiency. Therefore, designing a pulping device that addresses these deep-seated technical contradictions while simultaneously achieving flexible liquid level control, optimized agitation and overflow, significantly improved mixing efficiency, and effectively reduced energy consumption has become a key challenge and an urgent technical problem for those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-efficiency and energy-saving slurry preparation equipment for high-tower melting and granulation of compound fertilizer. Through the linkage adjustment of overflow level and stirring blade, the design of flow guide tube turbulence structure and gradient overflow hole group, the homogeneity and fluidity of slurry are significantly improved, while reducing energy consumption and enhancing adaptability to operating condition fluctuations.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A high-efficiency and energy-saving pulping device for high-tower melting and granulation of compound fertilizer includes a tank, an overflow outlet disposed above the side wall of the tank, and a stirring device disposed inside the tank. The stirring device includes a stirring shaft and stirring blades, and further includes:

[0011] An adjustable overflow sleeve is provided at the overflow outlet, including an inner sleeve provided on the inner wall of the tank, an outer sleeve sleeved outside the inner sleeve, and a lifting and adjusting mechanism for driving the outer sleeve to move up and down.

[0012] The inner sleeve has a set of longitudinal grid-shaped overflow holes arranged along the axial direction on its cylinder wall.

[0013] The lifting and adjusting mechanism is connected to the upper end of the stirring shaft and is used to drive the outer sleeve to move up and down to selectively cover or open the longitudinal grid strip overflow hole group at different heights, and simultaneously drive the stirring shaft and stirring blades to rise and fall.

[0014] Furthermore, the longitudinal grid strip overflow hole group includes three groups of overflow holes arranged sequentially along the axial direction of the inner sleeve: upper, middle, and lower. The length of the upper overflow hole group is 0.1 to 0.15 times the designed liquid level of the tank, with an opening ratio of 25% to 35%. The length of the middle overflow hole group is 0.15 to 0.25 times the designed liquid level of the tank, with an opening ratio of 35% to 45%. The length of the lower overflow hole group is 0.25 to 0.35 times the designed liquid level of the tank, with an opening ratio of 45% to 55%.

[0015] Furthermore, the longitudinal grid strip overflow hole group has rectangular slots with a width of 8-12 mm and a spacing of 15-25 mm between adjacent slots.

[0016] Furthermore, a guide tube is also provided inside the tank, and the stirring blades are located inside the guide tube; several sets of guide holes are axially arranged on the tube wall, and a turbulence baffle formed by stamping and bending the tube wall and located on the inner wall of the guide tube is provided at the guide holes.

[0017] Furthermore, a reverse baffle plate assembly is provided circumferentially at the bottom end of the guide tube. The reverse baffle plate assembly includes 4 to 8 baffle plates evenly spaced along the circumferential direction at the bottom end of the guide tube. The upper side of the baffle plates is inclined relative to the axis of the guide tube.

[0018] Furthermore, each of the baffle plates is provided with multiple turbulence holes, the diameter of which is 5 to 15 mm and the opening rate is 15% to 30%.

[0019] Furthermore, the lifting adjustment mechanism includes a vertically arranged adjusting screw and a connecting block; the upper end of the adjusting screw is provided with an adjusting nut, the adjusting screw passes through the upper cover of the tank body and is threadedly engaged with the connecting block; the connecting block is fixedly connected to the upper bearing seat of the outer sleeve and the stirring shaft respectively; the side of the adjusting nut is provided with a groove, and the upper cover of the tank body is provided with a limiting block adapted to the groove to restrict the axial movement of the adjusting nut.

[0020] Furthermore, the upper end of the stirring shaft is rotatably mounted on the tank cover via a bearing seat, and a sliding guide structure is provided between the bearing seat and the tank cover, so that the bearing seat can move up and down along the axial direction.

[0021] Furthermore, the pulping equipment includes three tanks connected in sequence: a melting tank, a primary mixing tank, and a secondary mixing tank. Each tank is equipped with an adjustable overflow sleeve, a lifting adjustment mechanism, and a stirring device.

[0022] Furthermore, the inner diameter of the outer sleeve is larger than the outer diameter of the inner sleeve, and a gap of 0.5 to 1.2 mm is maintained between the two; the pitch of the adjusting screw is 2.0 to 2.5 mm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) This invention achieves adaptive and coordinated adjustment of overflow level and stirring position by setting an adjustable overflow sleeve and a stirring blade lifting mechanism linked thereto. When the outer sleeve moves up and down to change the height of the open overflow hole group, the stirring blade rises and falls synchronously to the matching axial position, ensuring that the stirring action can effectively cover the mixing area under any set liquid level, avoiding mixing dead zones, significantly improving the homogeneity of the slurry, and reducing energy waste caused by liquid level fluctuations.

[0025] (2) The present invention provides a flow guide hole and a flow turbulence baffle on the wall of the flow guide cylinder, and sets a reverse flow baffle group in the circumferential direction at the bottom of the flow guide cylinder, so that the melt forms a complex turbulent field with multiple disturbances in the tank, which greatly enhances the mixing efficiency of the high viscosity melt, shortens the homogenization time, effectively reduces the local concentration gradient and temperature gradient, thereby improving the product quality stability of the subsequent granulation process.

[0026] (3) By setting three sets of longitudinal grid strip overflow holes with gradient changes in opening ratio and strip length on the inner sleeve, and combining them with the lifting and shielding of the outer sleeve, the present invention realizes multi-level control of liquid level, enabling the equipment to flexibly adapt to changes in operating conditions such as raw material ratio, heating power and discharge flow rate, thus expanding the applicability of pulping equipment and combining the advantages of high efficiency, energy saving and convenient operation. Attached Figure Description

[0027] Figure 1 and Figure 2 This is a cross-sectional view of the overall structure of the present invention;

[0028] Figure 3 This is a schematic diagram of the inner sleeve in this invention;

[0029] Figure 4 This is a partial cross-sectional view of the present invention;

[0030] Figure 5 This is a schematic diagram of the guide tube structure in this invention.

[0031] The corresponding names of the attached figures are as follows: 1. Discharge port; 2. Overflow discharge port; 3. Heating jacket; 4. Bearing seat; 5. Inner sleeve; 6. Outer sleeve; 7. Lifting and adjusting mechanism; 8. Longitudinal grid strip overflow hole group; 9. Adjusting screw; 10. Connecting block; 11. Adjusting nut; 12. Limiting block; 13. Stirring device; 14. Drive motor; 15. Stirring shaft; 16. Stirring blade; 17. Guide tube; 18. Support component; 19. Baffle plate; 20. Turbulence hole; 21. Guide hole; 22. Turbulence baffle plate; 23. Tank cover. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0033] like Figures 1-5As shown, this invention provides a high-efficiency and energy-saving pulping device for high-tower melting and granulation of compound fertilizer, comprising three tanks connected in sequence: a melting tank, a primary mixing tank, and a secondary mixing tank. The melting tank, primary mixing tank, and secondary mixing tank are all basic structures of existing pulping equipment in the art, connected in series via overflow: after the slurry in the melting tank reaches a set level, it overflows into the primary mixing tank, and then overflows into the secondary mixing tank, finally being sent to the granulation system through the outlet of the secondary mixing tank. Each tank has a cylindrical structure, with an outlet 1 at the bottom and an overflow outlet 2 on the upper side wall. A heating jacket 3 is provided on the outside of the tank for heating and maintaining the temperature of the material inside. A stirring device 13 is provided inside the tank for stirring and mixing the melt. This application makes the same improvements to all three tanks. Since the improved structures of each tank are the same, for the sake of simplicity, the technical solution of this invention will be described in detail below based only on the melting tank.

[0034] like Figure 2 As shown, the stirring device includes a drive motor 14, a stirring shaft 15, stirring blades 16, and a guide tube 17. The drive motor 14 is fixed to the top of the tank and connected to the stirring shaft 15 via a coupling, driving the stirring shaft 15 to rotate. The stirring blades 16 are fixed to the lower end of the stirring shaft 15 and rotate synchronously with the stirring shaft 15. The guide tube 17 is fixed to the inner wall of the tank and has a hollow cylindrical structure that runs vertically through the tank. The stirring blades 16 are disposed inside the guide tube 17.

[0035] In addition, the present invention also includes an overflow stirring linkage system, which comprises three parts: an adjustable overflow sleeve, a flow deflector, and a blade lifting linkage component. Each part is described in detail below:

[0036] (1) Adjustable overflow sleeve

[0037] like Figure 2 As shown, the adjustable overflow sleeve is installed at the overflow outlet on the side wall of the tank, including an inner sleeve 5, an outer sleeve 6, and a lifting adjustment mechanism that enables the outer sleeve 6 to move up and down.

[0038] like Figure 3As shown, the inner sleeve 5 is a cylindrical structure, and its wall is provided with multiple sets of longitudinal grid-shaped overflow hole groups 8 arranged sequentially along the axial direction. The longitudinal grid-shaped overflow hole groups 8 include upper, middle, and lower overflow hole groups arranged along the axial direction of the inner sleeve 5. The length of the overflow holes and the opening ratio of the overflow holes in different groups increase or decrease along the axial direction. Preferably, the length of the overflow holes in the upper group is 0.1 to 0.15 times the design liquid level of the tank, and the opening ratio is 25% to 35%; the length of the overflow holes in the middle group is 0.15 to 0.25 times the design liquid level of the tank, and the opening ratio is 35% to 45%; the length of the overflow holes in the lower group is 0.25 to 0.35 times the design liquid level of the tank, and the opening ratio is 45% to 55%. This design causes the overflow capacity of different groups of overflow holes to increase axially, meaning that the lower group of overflow holes has the longest orifice and the highest opening ratio, resulting in the strongest overflow capacity; while the upper group of overflow holes has the shortest orifice and the lowest opening ratio, resulting in the weakest overflow capacity.

[0039] The longitudinal grid strip overflow hole group 8 has rectangular slots with a width of 8-12 mm. The slots are arranged axially along the inner sleeve 5, and multiple slots form an overflow hole group with a spacing of 15-25 mm between adjacent slots.

[0040] like Figure 4 As shown, the outer sleeve 6 is fitted over the inner sleeve 5, and the inner diameter of the outer sleeve 6 is larger than the outer diameter of the inner sleeve 5, maintaining a gap of 0.5~1.2mm between them. The outer sleeve 6 is driven by a lifting adjustment mechanism 7, moving up and down relative to the inner sleeve 5 to selectively cover or open overflow orifice groups at different heights. Initially, the upper edge of the outer sleeve 6 is located at the lower end of the lower overflow orifice group of the inner sleeve 5, meaning all overflow orifice groups on the inner sleeve 5 are open. When the outer sleeve 6 moves upward, the lower overflow orifice group is covered, and the upper overflow orifice group is open, causing the liquid level to rise. When the outer sleeve returns to its original position downward, the lower overflow orifice group is opened, causing the liquid level to drop.

[0041] The lifting and adjusting mechanism 7 includes a vertically arranged adjusting screw 9 and a connecting block 10. An adjusting nut 11 is provided at the upper end of the adjusting screw 9, which passes through the tank cover 23 and extends to the outside of the tank. The adjusting screw 9 is threadedly engaged with the connecting block 10. The upper end of the stirring shaft 15 is rotatably mounted on the tank cover 23 via a bearing seat. A sliding guide structure is provided between the bearing seat and the tank cover 23, allowing the bearing seat to move axially up and down. The connecting block 10 is connected to both the outer sleeve 6 and the upper bearing seat of the stirring shaft 15. When the adjusting nut 11 is rotated, the adjusting screw 9 drives the connecting block 10 to move up and down, which in turn causes the outer sleeve 6 to move up and down relative to the inner sleeve 5, simultaneously causing the stirring shaft 15 and the stirring blades 16 to rise and fall synchronously. For the sliding guide structure, any conventional mechanical guide structure that can enable the bearing seat 4 to move freely axially relative to the upper cover 23 of the groove while restricting its radial and circumferential displacement is applicable to the present invention. For example, a vertical guide hole can be opened on the upper cover 23 of the groove, and a guide post adapted to the guide hole can be provided on the bearing seat 4; or at least one set of guide components consisting of linear bearings and guide shafts can be provided between the bearing seat 4 and the upper cover 23 of the groove.

[0042] The adjusting screw 9 is made of stainless steel with a pitch of 2.0~2.5mm. The connecting block 10 is made of cast iron, and the connecting block 10 is connected to the outer sleeve 6 by a flange. When the adjusting nut 11 is rotated, a groove is made on the side of the adjusting nut 11 to enable the adjusting screw 9 to move up and down. A limiting block 12 that matches the groove is set on the upper cover 23 of the groove. The limiting block 12 is inserted into the groove to restrict the axial movement of the adjusting nut 11. When the adjusting nut 11 is rotated, since the adjusting nut 11 cannot move up and down due to the limitation block 12, the adjusting screw 9 moves axially up and down relative to the adjusting nut 11 under the action of the threaded engagement, thereby driving the connecting block 10 and the outer sleeve 6 and the stirring shaft 15 fixedly connected to it to move up and down synchronously.

[0043] (2) Baffle tube

[0044] The flow deflector includes a flow deflector 17 fixedly installed in each tank and a reverse flow deflector plate assembly installed circumferentially at the bottom end of the flow deflector.

[0045] The guide tube 17 is a hollow cylindrical structure that runs vertically through the tank and is fixedly installed on the inner wall of the tank. The axial height of the guide tube 17 is 0.4 to 0.7 times the height of the tank, and the diameter of the guide tube 17 is 0.55 to 0.65 times the inner diameter of the tank. The guide tube 17 is made of corrosion-resistant stainless steel, and the wall thickness is 3 to 5 mm. The guide tube 17 is fixedly connected to the inner wall of the tank by a support member 18, one end of which is welded to the inner wall of the tank, and the other end is welded to the guide tube 17.

[0046] The guide tube 17 has several sets of axially arranged guide holes 21 on its wall, with an opening ratio of 10% to 30%. A turbulence-inducing baffle 22, formed by stamping and bending the tube wall, is provided at each guide hole 21, located on the inner wall of the guide tube 17. The presence of the turbulence-inducing baffle 22 creates turbulence in the melt passing through the guide holes 21, enhancing the turbulent mixing effect.

[0047] The stirring blade 16 is disposed inside the guide tube 17, and the diameter of the stirring blade 16 is 0.70 to 0.80 times the inner diameter of the guide tube 17. The stirring blade 16 is made of high-temperature alloy material, and the surface of the blade is strengthened to improve wear resistance.

[0048] A reverse baffle assembly is disposed circumferentially at the bottom end of the guide tube 17, comprising 4 to 8 baffles 19 evenly spaced along the circumferential direction of the bottom end of the guide tube 17. Preferably, the reverse baffle assembly comprises 6 baffles, evenly spaced along the circumferential direction of the bottom end of the guide tube 17. The upper side of the baffles 19 is inclined relative to the axis of the guide tube 17. When the melt flows upward to the liquid surface under the drive of the stirring blade 16 and then flows downward, it will impact these inclined baffles 19, thereby generating strong disturbance and redistribution, forming a complex flow pattern in the tank.

[0049] Each baffle plate 19 has multiple turbulence holes 20 with a diameter of 5-15 mm and an opening rate of 15%-30%. The presence of the turbulence holes 20 further enhances the turbulence effect, enabling the melt to form a fully mixed turbulent field in the tank.

[0050] (3) Paddle lifting linkage

[0051] The impeller lifting linkage enables coordinated adjustment of the position of the stirring impeller 16 and the height of the overflow hole assembly. In the lifting adjustment mechanism 7, the connecting block 10 is fixedly connected to both the outer sleeve 6 and the upper bearing seat of the stirring shaft 15. When the adjusting nut 11 is rotated, the adjusting screw 9 drives the connecting block 10 to move up and down, which in turn causes the outer sleeve 6 to move up and down relative to the inner sleeve 5, simultaneously causing the stirring shaft 15 and the stirring impeller 16 to rise and fall synchronously.

[0052] Specifically, when the lifting and adjusting mechanism 7 raises the outer sleeve 6 to cover the lower overflow hole group and open the upper overflow hole group, the connecting block 10 drives the stirring shaft 15 to move upward, causing the stirring blade 16 to be raised accordingly to the upper section of the guide tube corresponding to the upper overflow hole group. At this time, the liquid level in the tank is high, the stirring blade is located in the upper part of the guide tube, and the stirring effect covers the entire liquid surface height, avoiding the occurrence of mixing dead zones.

[0053] When the outer sleeve descends to the open lower overflow hole group, the connecting block drives the stirring shaft to move downwards, causing the stirring blades to descend accordingly to the lower section of the guide tube corresponding to the lower overflow hole group. At this time, the liquid level in the tank is low, the stirring blades are located at the lower part of the guide tube, and the stirring effect is concentrated in the lower part of the tank, ensuring the mixing effect.

[0054] This design ensures that the stirring blades can achieve the best mixing effect in the most suitable position under any liquid level conditions, realizing the synergy between liquid level adjustment and stirring position adjustment.

[0055] The working principle of the above equipment is as follows: When the liquid level in the tank is low, the operator rotates the adjusting nut to lower the outer sleeve, opening the lower overflow hole group. At this time, the overflow conditions of the lower overflow hole group are most favorable, and the liquid level stabilizes at the height corresponding to the lower overflow hole group. At the same time, the stirring blades descend to the lower section of the guide tube, and the stirring effect is concentrated in the lower part of the tank. When the liquid level in the tank needs to be raised, the operator rotates the adjusting nut to raise the outer sleeve, covering the lower overflow hole group and opening the upper overflow hole group. The liquid level then rises to the height corresponding to the upper overflow hole group. At this time, the stirring blades rise to the upper section of the guide tube, and the stirring effect covers the entire liquid surface height.

[0056] During the stirring process, the impeller drives the melt to flow upwards along the guide tube. The melt passes through the guide holes on the tube wall and enters the area outside the tube. The baffles at the guide holes create turbulence in the melt, enhancing the turbulent mixing effect. After reaching the surface, the melt flows downwards and encounters a set of counter-flow baffles at the bottom of the guide tube, forming a complex flow pattern. The small turbulence holes on the baffles further enhance the turbulence effect, creating a fully mixed turbulent field within the tank.

[0057] After making the above improvements to the melting tank, primary mixing tank, and secondary mixing tank, the complete pulping process is as follows:

[0058] First, the raw material enters the melting tank. The heating device (heating jacket) of the melting tank heats the raw material to melt it, while the stirring device drives the melt to form a circulating flow. The liquid level in the melting tank rises as the raw material melts. When the liquid level reaches the height corresponding to the flow hole group, the melt overflows through the overflow hole group and enters the primary mixing tank.

[0059] In the primary mixing tank, the melt from the melting tank is mixed with pre-metered powdered monoammonium phosphate, potassium chloride, potassium sulfate, additives, and other solid materials. A heating device maintains the tank temperature, while a stirring device drives the slurry to circulate. The liquid level in the primary mixing tank is also controlled by an adjustable overflow sleeve, and the slurry enters the secondary mixing tank through an overflow orifice assembly.

[0060] In the secondary mixing tank, the slurry is further homogenized and its temperature is regulated. The counter-current baffle assembly and the turbulence-inducing baffles on the guide tube work together to create a strong turbulent mixing environment within the tank, significantly improving the homogenization of the slurry. The slurry is then transported to the granulation system from the bottom outlet of the secondary mixing tank.

[0061] When changes in operating conditions require adjustment of the liquid level, the operator adjusts the position of the outer sleeve using the adjusting nut. The raising and lowering of the outer sleeve drives the stirring shaft to rise and fall synchronously, achieving coordinated adjustment of the liquid level and the stirring position. This design ensures that, under any liquid level condition, the stirring blades can achieve the best mixing effect in the most suitable position, guaranteeing mixing quality while reducing energy consumption.

[0062] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A high-efficiency and energy-saving pulping device for high-tower melting and granulation of compound fertilizer, comprising a tank, an overflow outlet (2) disposed above the side wall of the tank, and a stirring device (13) disposed inside the tank, wherein the stirring device (13) comprises a stirring shaft (15) and stirring blades (16), characterized in that, Also includes: An adjustable overflow sleeve is provided at the overflow outlet (2), including an inner sleeve (5) provided on the inner wall of the tank, an outer sleeve (6) sleeved outside the inner sleeve (5), and a lifting adjustment mechanism (7) for driving the outer sleeve (6) to move up and down. The inner sleeve (5) is provided with a longitudinal grid strip overflow hole group (8) arranged along the axial direction. The lifting adjustment mechanism (7) is connected to the upper end of the stirring shaft (15) and is used to drive the outer sleeve (6) to move up and down to selectively cover or open the longitudinal grid strip overflow hole group (8) at different heights, and simultaneously drive the stirring shaft (15) and stirring blade (16) to rise and fall.

2. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 1, characterized in that, The longitudinal grid strip overflow hole group (8) includes three overflow hole groups arranged sequentially along the axial direction of the inner sleeve (5): upper, middle and lower. The length of the strip hole of the upper overflow hole group is 0.1 to 0.15 times the designed liquid level of the tank, and the opening ratio is 25% to 35%. The length of the strip hole of the middle overflow hole group is 0.15 to 0.25 times the designed liquid level of the tank, and the opening ratio is 35% to 45%. The length of the strip hole of the lower overflow hole group is 0.25 to 0.35 times the designed liquid level of the tank, and the opening ratio is 45% to 55%.

3. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 2, characterized in that, The longitudinal grid strip overflow hole group (8) has rectangular slots with a width of 8-12 mm and a spacing of 15-25 mm between adjacent slots.

4. A high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 1 or 3, characterized in that, The tank is also equipped with a flow guide cylinder (17), and the stirring blade (16) is located inside the flow guide cylinder (17). The flow guide cylinder (17) has several sets of axially arranged flow guide holes (21) on its wall. The flow guide holes (21) are equipped with turbulence baffles (22) formed by the stamping and bending of the wall and located on the inner wall of the flow guide cylinder (17).

5. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 4, characterized in that, The bottom end of the guide tube (17) is provided with a reverse baffle plate group, which includes 4 to 8 baffle plates (19) evenly spaced along the circumferential direction of the bottom end of the guide tube (17); the upper side of the baffle plate (19) is inclined relative to the axis of the guide tube (17).

6. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 5, characterized in that, Each of the baffle plates (19) has multiple turbulence holes (20) with a diameter of 5 to 15 mm and an opening rate of 15% to 30%.

7. The high-efficiency and energy-saving pulping equipment for high-tower melt granulation of compound fertilizer according to claim 6, characterized in that, The lifting adjustment mechanism (7) includes a vertically arranged adjusting screw (9) and a connecting block (10); the upper end of the adjusting screw (9) is provided with an adjusting nut (11), the adjusting screw (9) passes through the upper cover of the tank body (23) and is threadedly engaged with the connecting block (10); the connecting block (10) is fixedly connected to the upper bearing seat of the outer sleeve (6) and the stirring shaft (15) respectively; the side of the adjusting nut (11) is provided with a groove, and the upper cover of the tank body (23) is provided with a limiting block (12) that matches the groove to limit the axial movement of the adjusting nut (11).

8. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 7, characterized in that, The upper end of the stirring shaft (15) is rotatably mounted on the tank cover (23) via a bearing seat. A sliding guide structure is provided between the bearing seat and the tank cover (23), so that the bearing seat can move up and down along the axial direction.

9. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 8, characterized in that, The pulping equipment includes three tanks connected in sequence: a melting tank, a primary mixing tank, and a secondary mixing tank. Each tank is equipped with an adjustable overflow sleeve, a lifting adjustment mechanism (7), and a stirring device (13).

10. The high-efficiency and energy-saving pulping equipment for high-tower melting granulation of compound fertilizer according to claim 9, characterized in that, The inner diameter of the outer sleeve (6) is larger than the outer diameter of the inner sleeve (5), and a gap of 0.5 to 1.2 mm is maintained between them; the pitch of the adjusting screw (9) is 2.0 to 2.5 mm.

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