Spray drying device for preparing pullulan

Abstract

The invention discloses a spray drying device for pullulan preparation, and relates to the technical field of spray drying, the spray drying device comprises a drying tank, the top of the drying tank is fixedly connected with an air inlet, the bottom of the air inlet is fixedly connected with an atomizer, the bottom of the drying tank is fixedly connected with supporting legs, and the bottom of the drying tank is fixedly connected with an air outlet valve. A uniform drying mechanism is arranged at the bottom of the drying tank and can be directly and uniformly blown away by hot air located in the middle in the drying tank, and the problem that atomized liquid beads are single in hot air flowing direction due to the fact that a traditional hot air inlet nozzle is located on the single side face is solved. The problem that atomized liquid beads are not uniform in flowing space in a drying tank is solved, the situation that part of the liquid beads are gathered together to form large water beads due to non-uniform flowing of the atomized liquid beads is avoided, and the problem that the spray drying efficiency is reduced due to the fact that the contact area between each liquid bead and hot air is reduced is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of spray drying, and particularly to a spray drying device for preparing pullulan polysaccharide. Background Art

[0002] When pullulan polysaccharide is industrially produced, due to the high cost of vacuum freeze-drying, spray drying is generally preferred for industrial production. The existing spray dryer sprays the feed liquid into fine mist droplets through a centrifugal atomizer and makes them contact with the hot air in the drying tower for drying; A spray drying device for preparing pullulan polysaccharide described in the patent application with the publication number CN218608058U includes: a drying tower and an air heater. A communicating pipe is connected between the drying tower and the air heater. A blower is arranged on the air heater. The top and bottom of the drying tower are respectively connected with a centrifugal atomizer and a pipeline, and a stand is connected to the outside of the drying tower; it further includes: an auxiliary drying component, which is arranged in the inner cavity of the drying tower and extends outwards. The auxiliary drying component is used to dry the materials in the inner cavity of the drying tower sufficiently. In this spray drying device for preparing pullulan polysaccharide, by setting the auxiliary drying component, the cam rotates continuously, and then the screen moves up and down continuously. When the screen moves upwards, the elastic force generated by the spring is used to shake the materials on the screen upwards, so that the hot air in the inner cavity of the drying tower can dry the materials sufficiently; At present, when preparing pullulan polysaccharide, the spray drying system used will have problems such as blockage of the spray nozzle due to the long-term use of the spray head and the viscosity of the liquid in the preparation raw materials, resulting in uneven spraying. At the same time, one of the hot air outlets or spray nozzles is usually on one side of the drying tower, which will cause uneven spraying of one of the hot air or spray, affecting the overall drying efficiency and drying uniformity of the spray drying. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a spray drying device for preparing pullulan polysaccharide, achieving the purpose of solving the above problems.

[0004] To achieve the above object, the present invention is realized through the following technical solutions: A spray drying device for preparing pullulan polysaccharide, including a drying tank, an air inlet is fixedly connected to the top of the drying tank, an atomizer is fixedly connected to the bottom of the air inlet, support legs are fixedly connected to the bottom of the drying tank, an air outlet valve is fixedly connected to the bottom of the drying tank, and a uniform drying mechanism is arranged at the bottom of the drying tank; The uniform drying mechanism includes: A motor, the motor is fixedly connected to the bottom of the drying tank, a rotating shaft is fixedly connected to the output end of the motor, a hot air pipe is fixedly connected to the outer wall of the drying tank, a communicating pipe is arranged inside the drying tank, and the motor is used to drive the rotating shaft to rotate; A hemispherical block, a spraying port is arranged on the inner wall of the hemispherical block, a bearing ring is fixedly connected to the bottom of the hemispherical block, and the bottom of the bearing ring is fixedly connected to one end of the rotating shaft. The hemispherical block is used to spray hot air.

[0005] Preferably, a connecting ring is fixedly connected to the outer wall of the bearing ring, and the inner wall of the connecting ring is fixedly connected to the outer wall of the hemispherical block.

[0006] Preferably, the connecting ring is of a circular ring structure, a fixing ring is fixedly connected to the inner wall of the drying tank, a bearing ring is fixedly connected to the inner wall of the fixing ring, a communicating pipe is fixedly connected to the outer wall of the bearing ring, and one end of the communicating pipe is fixedly connected to the inner wall of the drying tank.

[0007] Preferably, a jet ring is fixedly connected to the inner wall of the bearing ring, a second communication groove is arranged on the outer wall of the jet ring, a fixing ring is slidably connected to the outer wall of the jet ring, and the outer wall of the fixing ring is fixedly connected to the inner wall of the drying tank.

[0008] Preferably, the fixing ring is internally communicated with the hot air pipe, a first communication groove is arranged on the inner wall of the fixing ring, and the first communication groove is communicated with the second communication groove.

[0009] Preferably, a first hot air groove is arranged at the top of the jet ring, a second hot air groove is arranged at the bottom of the jet ring, and a third hot air groove is arranged at the bottom of the bearing ring.

[0010] Preferably, an ultrasonic dispersion mechanism is arranged on the outer wall of the connecting ring. The ultrasonic dispersion mechanism includes a first connecting rod, one end of the first connecting rod is fixedly connected to the outer wall of the connecting ring, the other end of the first connecting rod is fixedly connected to an ultrasonic generator, and an ultrasonic vibrating rod is fixedly connected to one end of the ultrasonic generator.

[0011] Preferably, a second connecting rod is fixedly connected to one end of the ultrasonic vibrating rod, one end of the second connecting rod is fixedly connected to the inner wall of the jet ring, a first inclined plate is fixedly connected to the outer wall of the rotating shaft, and a second inclined plate is fixedly connected to the bottom of the jet ring.

[0012] The present invention provides a spray drying device for preparing pullulan polysaccharide. It has the following beneficial effects: 1. By setting up a uniform drying mechanism, the present invention uses several spraying ports on the surface of the hemispherical block to perform a hemispherical annular spraying upward, so that the atomized liquid beads sprayed outward by the atomizer above can be directly and evenly blown by the hot air at the middle position in the drying tank, avoiding the problem that the nozzle position for introducing traditional hot air is on a single side, resulting in a single direction of hot air flow and uneven flow space of the atomized liquid beads in the drying tank. It also avoids the situation where some liquid beads gather together and agglomerate into large water droplets due to uneven flow of the atomized liquid beads, reducing the contact area between each liquid bead and the hot air, thus avoiding the problem of reduced spray drying efficiency.

[0013] 2. By setting up a uniform drying mechanism, the present invention evenly sprays outward from the center position of the drying tank through the spraying ports, which can also avoid the hot air blowing in a traditional single direction, resulting in the liquid beads adhering to one side of the inner wall of the drying tank along with the airflow, causing the liquid beads to condense on the inner wall of the drying tank and form water droplets that slide off, greatly reducing the atomization drying effect. 3. By setting up a uniform drying mechanism, the present invention uses the third hot air groove to perform an annular air curtain blowing downward to achieve multi-position hot air diversion when hot air enters the drying tank. Since the openings of the first hot air groove, the second hot air groove, and the third hot air groove are small, the air pressurized into the hot air pipe will be ejected with a relatively large pressure through the first hot air groove, the second hot air groove, and the third hot air groove to form an annular air curtain. 4. By setting up a uniform drying mechanism, the formed air curtain can block the intrusion of liquid beads and form a whole air wall protection for the upper part, lower part of the inner wall of the drying tank, and the outer wall of the rotating shaft, avoiding the problem that a large number of liquid beads sprayed out by the atomizer in the atomizer float with their inertia and adhere to the inner wall of the drying tank and the rotating shaft. It also further avoids the problem that because the liquid beads are easily naturally attached to the inner wall of the drying tank and agglomerate and fuse into larger water droplets and roll on the inner wall of the drying tank, thus avoiding the problem of being unable to utilize the large contact area between the atomized liquid beads and the air for drying. At the same time, it also avoids the corrosion of the inner wall of the drying tank due to frequent attachment of liquid beads during long-term spray drying. 5. By setting up a uniform drying mechanism, and at the same time, the air spraying in the form of an air curtain can play a role in downward drainage of the atomized liquid beads, ensuring that the hot air flow direction in the drying tank is evenly downward, reducing the problem that the atomized liquid beads in the space of the drying tank gather together and converge into water droplets, thereby improving the drying effect of atomization drying. 6. The present invention sets an ultrasonic dispersion mechanism, and utilizes the rotation of the first connecting rod, the ultrasonic generator, and the ultrasonic vibration rod to rotate the atomized liquid droplets and the hot air from top to bottom, so that the atomized liquid droplets can quickly contact with the hot air, and improve the fusion uniformity of the hot air and the atomized liquid droplets, thereby avoiding the problem of uneven contact with the hot air when the spraying port inside the atomizer is partially blocked due to long-term atomization spraying, thereby further improving the drying efficiency; 7. The present invention sets an ultrasonic dispersion mechanism, and the ultrasonic generator starts to control the ultrasonic vibration rod to generate ultrasonic waves at the same time, so that when the ultrasonic vibration rod rotates to stir and mix the atomized liquid droplets, the liquid droplets and hot air passing by are also ultrasonically vibrated synchronously, so that the liquid droplets are further dispersed and contacted with the hot air. Accompanied by the uniform mixing of the air, the evaporation efficiency of the liquid droplets by the heated air can be more effectively improved, thereby avoiding the problem that the liquid droplets are too large to be evaporated and dried by the hot air; 8. The present invention provides an ultrasonic dispersion mechanism. Once any liquid droplets or water droplets approach the inner wall of the drying tank, they will be pushed out by the second inclined plate and the first inclined plate at an obtuse angle, so that they can be separated from the inner wall of the drying tank and the outer wall of the rotating shaft, thereby protecting the inner wall of the drying tank from being contaminated by the liquid droplets as much as possible, and allowing the rotating shaft to drive the ultrasonic generator and the ultrasonic vibration rod to push the liquid droplets evenly while avoiding the problem of the rotating shaft itself being contaminated by the liquid droplets. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the structural cross section of the present invention; Figure 3 The structure of the uniform drying mechanism of the present invention is shown in FIG. Figure 1 ; Figure 4 The structure of the uniform drying mechanism of the present invention is shown in FIG. Figure 2 ; Figure 5 The structure of the uniform drying mechanism of the present invention is shown in FIG. Figure 3 ; Figure 6 The schematic diagram of the structural disassembly of the uniform drying mechanism of the present invention is shown in FIG. Figure 1 ; Figure 7 The structure of the uniform drying mechanism of the present invention is shown in FIG. Figure 4 ; Figure 8 The schematic diagram of the structural disassembly of the uniform drying mechanism of the present invention is shown in FIG. Figure 2 ; Figure 9 It is a structural schematic diagram of the hemispherical block of the present invention; Figure 10 Structural schematic of the drying mechanism of the present invention Figure 5 ; Figure 11 Structural sectional view of the drying mechanism of the present invention; Figure 12 For the present invention Figure 3 Enlarged view of part A; Figure 13 For the present invention Figure 3 Enlarged view of part B.

[0015] In the figure: 1, support leg; 2, drying tank; 3, uniform drying mechanism; 301, motor; 302, rotating shaft; 304, hot air pipe; 305, fixing ring; 306, jet ring; 307, first communication groove; 308, second communication groove; 309, connecting pipe; 310, bearing ring; 311, hemispherical block; 312, spraying port; 313, connecting ring; 314, first hot air groove; 315, second hot air groove; 316, third hot air groove; 4, ultrasonic dispersion mechanism; 401, first connecting rod; 402, ultrasonic generator; 403, ultrasonic vibrating rod; 404, second connecting rod; 405, first inclined plate; 406, second inclined plate; 5, air inlet; 6, atomizer; 7, air outlet valve. Specific embodiments

[0016] Embodiment 1: Please refer to Figures 1-4 , the present invention provides a technical solution: a spray drying device for preparing pullulan polysaccharide, including a drying tank 2, an air inlet 5 is fixedly connected to the top of the drying tank 2, an atomizer 6 is fixedly connected to the bottom of the air inlet 5, a support leg 1 is fixedly connected to the bottom of the drying tank 2, an air outlet valve 7 is fixedly connected to the bottom of the drying tank 2, and a uniform drying mechanism 3 is arranged at the bottom of the drying tank 2; The uniform drying mechanism 3 includes: A motor 301, the motor 301 is fixedly connected to the bottom of the drying tank 2, the output end of the motor 301 is fixedly connected to a rotating shaft 302, a hot air pipe 304 is fixedly connected to the outer wall of the drying tank 2, a connecting pipe 309 is arranged inside the drying tank 2, and the motor 301 is used to drive the rotation of the rotating shaft 302; A hemispherical block 311, a spraying port 312 is opened on the inner wall of the hemispherical block 311, a bearing ring 310 is fixedly connected to the bottom of the hemispherical block 311, and the bottom of the bearing ring 310 is fixedly connected to one end of the rotating shaft 302. The hemispherical block 311 is used for jetting hot air; Press the liquid to the air inlet 5, then enter the atomizer 6 through the air inlet 5 and atomize and spray it externally, turning the liquid into a large number of fine liquid beads. Then, connect a hot air pump externally through the hot air pipe 304 to blow hot air into the drying tank 2 to quickly dry the atomized liquid beads into powder. The dry powder and the wet air are discharged outward through the air outlet valve 7 below to the subsequent cyclone dust collector for subsequent separation work, thus completing the spray drying work; When performing spray drying, the hot air entering through the hot air pipe 304 will enter the bearing ring 310 through the fixed ring 305 and the connecting pipe 309, and communicate with the spraying port 312 inside the bearing ring 310 and the hemispherical block 311, and spray out through the spraying port 312. At the same time, start the motor 301 to drive the rotating shaft 302, the bearing ring 310 and the hemispherical block 311 to start rotating, and use several spraying ports 312 on the surface of the hemispherical block 311 to perform hemispherical annular spraying upward, so that the atomized liquid beads sprayed outward through the atomizer 6 above can be directly and evenly blown by the hot air located in the middle of the drying tank 2, avoiding the problem that the spray port position of the traditional hot air inlet is on a single side, resulting in a single direction of hot air flow and uneven flow space in the drying tank 2 for the atomized liquid beads, and also avoiding the situation where some liquid beads gather together and aggregate into large water droplets due to uneven flow of the atomized liquid beads, reducing the contact area between each liquid bead and the hot air, thus resulting in the problem of reduced spray drying efficiency; Embodiment 2: Please refer to Figures 1-11 , on the basis of Embodiment 1, the present invention provides a technical solution: a traditional atomization drying device. However, this traditional method has obvious defects. The atomized liquid beads are easy to aggregate into larger droplets in the drying chamber. These large droplets are difficult to be quickly evaporated and dried by hot air, which prolongs the drying time, reduces the drying effect, and also increases the risk of equipment blockage. The inner wall of the drying chamber is also easily eroded. During the drying process, the dust and moisture generated by the spray are easily attached to the inner wall of the drying chamber. Long-term accumulation will cause corrosion and scaling of the inner wall, affecting the normal operation and service life of the equipment. Therefore, a connecting ring 313 is fixedly connected to the outer wall of the bearing ring 310, and the inner wall of the connecting ring 313 is fixedly connected to the outer wall of the hemispherical block 311.

[0017] The connecting ring 313 is a circular ring structure. A fixed ring 305 is fixedly connected to the inner wall of the drying tank 2, a bearing ring 310 is fixedly connected to the inner wall of the fixed ring 305, a connecting pipe 309 is fixedly connected to the outer wall of the bearing ring 310, and one end of the connecting pipe 309 is fixedly connected to the inner wall of the drying tank 2.

[0018] A jet ring 306 is fixedly connected to the inner wall of the bearing ring 310. A second communication groove 308 is opened on the outer wall of the jet ring 306. The outer wall of the jet ring 306 is slidably connected to the fixed ring 305, and the outer wall of the fixed ring 305 is fixedly connected to the inner wall of the drying tank 2.

[0019] The fixed ring 305 is internally connected to the hot air pipe 304. A first communication groove 307 is formed on the inner wall of the fixed ring 305, and the first communication groove 307 is communicated with the second communication groove 308.

[0020] A first hot air groove 314 is formed at the top of the jet ring 306, a second hot air groove 315 is formed at the bottom of the jet ring 306, and a third hot air groove 316 is formed at the bottom of the bearing ring 310. By evenly spraying outward from the central position of the drying tank 2 through the spraying port 312 in a decentralized manner, it can also avoid the hot air blowing in a traditional single direction, resulting in the liquid beads adhering to one side of the inner wall of the drying tank 2 along with the airflow, causing the liquid beads to condense on the inner wall of the drying tank 2 to form water droplets and slide off, greatly reducing the effect of atomization drying. The hot air enters the fixed ring 305 through the hot air pipe 304, and is interconnected through the first communication groove 307 and the second communication groove 308 between the fixed ring 305 and the jet ring 306. Even if the jet ring 306 and the fixed ring 305 rotate relative to each other, air can be communicated through the annular first communication groove 307 and the second communication groove 308, and the air enters the jet ring 306. Through the connection between the jet ring 306 and the connecting pipe 309, the hot air finally enters the spraying port 312. At the same time, the hot air in the jet ring 306 will also form an annular air curtain blowing through the first hot air groove 314 and the second hot air groove 315 at the top and bottom of the jet ring 306. Part of the air entering the bearing ring 310 is communicated with the spraying port 312 on the inner wall of the hemispherical block 311, and the other part is communicated with the third hot air groove 316 at the bottom of the bearing ring 310. Similarly, the third hot air groove 316 is used to perform annular air curtain blowing downward to achieve multi-position hot air diversion of the hot air entering the drying tank 2. Since the openings of the first hot air groove 314, the second hot air groove 315, and the third hot air groove 316 are small, the air pressurized into the hot air pipe 304 will be ejected with a relatively large pressure through the first hot air groove 314, the second hot air groove 315, and the third hot air groove 316 to form an annular air curtain. The formed air curtain can block the intrusion of liquid beads, forming an entire air wall protection for the upper part, lower part of the inner wall of the drying tank 2, and the outer wall of the rotating shaft 302, which can avoid the problem that a large number of liquid beads atomized and sprayed out of the atomizer 6 float with their inertia and adhere to the inner wall of the drying tank 2 and the rotating shaft 302. It also further avoids the problem that because the liquid beads are easily naturally attached to the inner wall of the drying tank 2 and coagulate and fuse into larger water droplets and roll on the inner wall of the drying tank 2, thus avoiding the problem that the atomized liquid beads cannot be dried by using their large contact area with the air. At the same time, it also avoids the corrosion of the inner wall of the drying tank 2 due to frequent attachment of liquid beads during long-term spray drying. Meanwhile, the air spraying in the form of an air curtain can play a role in downward drainage of the atomized liquid droplets, ensuring that the hot air flow in the drying tank 2 is evenly downward, reducing the problem that the atomized liquid droplets in the space of the drying tank 2 gather together to form water droplets, and then improving the drying effect of atomization drying; Embodiment 3: Please refer to Figures 1-13 , based on Embodiment 1 and Embodiment 2, the present invention provides a technical solution: When the spraying force of atomization drying is relatively large, there may be a situation where some liquid droplets break through the air curtain and contaminate the inner wall of the drying tank 2. At the same time, if the rotating shaft 302 of the traditional driving stirring rod is directly set, the atomized liquid droplets will also break through the air curtain below the third hot air groove 316 and contaminate the vertically centered rotating shaft 302. And long-term adhesion will cause corrosion problems on the inner wall of the drying tank 2 and the rotating shaft 302. Therefore, an ultrasonic dispersion mechanism 4 is arranged on the outer wall of the connecting ring 313. The ultrasonic dispersion mechanism 4 includes a first connecting rod 401. One end of the first connecting rod 401 is fixedly connected to the outer wall of the connecting ring 313, and the other end of the first connecting rod 401 is fixedly connected to an ultrasonic generator 402. One end of the ultrasonic generator 402 is fixedly connected to an ultrasonic vibrating rod 403.

[0021] One end of the ultrasonic vibrating rod 403 is fixedly connected to a second connecting rod 404. One end of the second connecting rod 404 is fixedly connected to the inner wall of the air jet ring 306. The outer wall of the rotating shaft 302 is fixedly connected to a first inclined plate 405. The bottom of the air jet ring 306 is fixedly connected to a second inclined plate 406; At the same time, when the rotating shaft 302 rotates, it will drive the first connecting rod 401, the ultrasonic generator 402, and the ultrasonic vibrating rod 403 to rotate together. The rotation of the first connecting rod 401, the ultrasonic generator 402, and the ultrasonic vibrating rod 403 is used to stir and rotate the atomized liquid droplets and hot air from top to bottom, so that the atomized liquid droplets can quickly contact the hot air and improve the uniformity of the fusion of the hot air and the atomized liquid droplets. It avoids the problem that when the spraying port inside the atomizer 6 is partially blocked during long-term atomization spraying, resulting in uneven spraying and uneven contact with the hot air, and then further improves the drying efficiency; The ultrasonic generator 402 is simultaneously started to control the ultrasonic vibrating rod 403 to generate ultrasonic waves. When the ultrasonic vibrating rod 403 rotates to stir and mix the atomized liquid droplets evenly, it also synchronously performs ultrasonic vibration on the surrounding passing liquid droplets and hot air, causing the liquid droplets to be further dispersed and contact the hot air. Along with the uniform mixing of the stirred air, it can more effectively improve the evaporation efficiency of the liquid droplets by the hot air, thereby avoiding the problem that the liquid droplets are too large to be evaporated and dried by the hot air; When the rotating shaft 302 rotates, it will also drive the bearing ring 310, the connecting ring 313, the first connecting rod 401, the ultrasonic generator 402, the ultrasonic vibration rod 403, the second connecting rod 404 and the air jet ring 306 to rotate, so that the air curtains ejected by the first hot air groove 314 and the second hot air groove 315 rotate synchronously, making the coverage of the inner wall of the drying tank 2 by the air curtains more uniform, so that the inner wall of the drying tank 2 can be uniformly blocked by the air curtains and not be eroded by spray dust and moisture. At the same time, the air jet ring 306 and the rotating shaft 302 will drive the second inclined plate 406 and the first inclined plate 405 on their outer walls to rotate synchronously. The second inclined plate 406 and the first inclined plate 405 are inclined. The rotation direction of the rotating shaft 302 can make the second inclined plate 406 and the first inclined plate 405 stir the air inside the drying tank 2 in the form of an obtuse angle. Thus, once any liquid droplets or water droplets approach the inner wall of the drying tank 2, they will be stirred by the second inclined plate 406 and the first inclined plate 405 in the form of an obtuse angle and thrown out, so that they are separated from the inner wall of the drying tank 2 and the outer wall of the rotating shaft 302, protecting the inner wall of the drying tank 2 from being contaminated by liquid droplets as much as possible. Also, when the rotating shaft 302 drives the ultrasonic generator 402 and the ultrasonic vibration rod 403 to stir the liquid droplets evenly, it can avoid the problem that the rotating shaft 302 itself is contaminated by liquid droplets.

[0022] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A spray drying device for preparing pullulan, comprising a drying tank (2), wherein the top of the drying tank (2) is fixedly connected to an air inlet (5), the bottom of the air inlet (5) is fixedly connected to an atomizer (6), the bottom of the drying tank (2) is fixedly connected to a support leg (1), and the bottom of the drying tank (2) is fixedly connected to an air outlet valve (7), characterized in that: A uniform drying mechanism (3) is provided at the bottom of the drying tank (2); The uniform drying mechanism (3) comprises: A motor (301), the motor (301) being fixedly connected to the bottom of the drying tank (2), the output end of the motor (301) being fixedly connected to a rotating shaft (302), the outer wall of the drying tank (2) being fixedly connected to a hot air pipe (304), a connecting pipe (309) being provided inside the drying tank (2), and the motor (301) being used to drive the rotating shaft (302) to rotate; A hemispherical block (311) is provided with a spraying port (312) on its inner wall, a bearing ring (310) is fixedly connected to the bottom of the hemispherical block (311), the bottom of the bearing ring (310) is fixedly connected to one end of the rotating shaft (302), and the hemispherical block (311) is used to spray hot air.

2. A spray drying device for preparing pullulan according to claim 1, characterized in that: The outer wall of the bearing ring (310) is fixedly connected to a connecting ring (313), and the inner wall of the connecting ring (313) is fixedly connected to the outer wall of the hemispherical block (311).

3. A spray drying device for preparing pullulan according to claim 2, characterized in that: The connecting ring (313) is a circular ring structure; the inner wall of the drying tank (2) is fixedly connected to a fixing ring (305); the inner wall of the fixing ring (305) is fixedly connected to a bearing ring (310); the outer wall of the bearing ring (310) is fixedly connected to a connecting pipe (309); one end of the connecting pipe (309) is fixedly connected to the inner wall of the drying tank (2).

4. A spray drying device for preparing pullulan according to claim 3, characterized in that: The inner wall of the bearing ring (310) is fixedly connected to an air jet ring (306), the outer wall of the air jet ring (306) is provided with a second connecting groove (308), the outer wall of the air jet ring (306) is slidably connected to a fixing ring (305), and the outer wall of the fixing ring (305) is fixedly connected to the inner wall of the drying tank (2).

5. A spray drying device for preparing pullulan according to claim 4, characterized in that: The fixing ring (305) is connected to the inside of the hot air pipe (304); a first connecting groove (307) is provided on the inner wall of the fixing ring (305); and the first connecting groove (307) is connected to the second connecting groove (308).

6. A spray drying device for preparing pullulan according to claim 5, characterized in that: The top of the jet ring (306) is provided with a first hot air groove (314), the bottom of the jet ring (306) is provided with a second hot air groove (315), and the bottom of the bearing ring (310) is provided with a third hot air groove (316).

7. A spray drying device for preparing pullulan according to claim 6, characterized in that: An ultrasonic dispersion mechanism (4) is provided on the outer wall of the connecting ring (313), and the ultrasonic dispersion mechanism (4) comprises a first connecting rod (401), one end of the first connecting rod (401) is fixedly connected to the outer wall of the connecting ring (313), the other end of the first connecting rod (401) is fixedly connected to an ultrasonic generator (402), and one end of the ultrasonic generator (402) is fixedly connected to an ultrasonic vibration rod (403).

8. A spray drying device for preparing pullulan according to claim 7, characterized in that: One end of the ultrasonic vibration rod (403) is fixedly connected to a second connecting rod (404), one end of the second connecting rod (404) is fixedly connected to the inner wall of the jet ring (306), the outer wall of the rotating shaft (302) is fixedly connected to a first inclined plate (405), and the bottom of the jet ring (306) is fixedly connected to a second inclined plate (406).

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