Spray drying equipment

Abstract

The invention relates to the technical field of material drying, in particular to spray drying equipment. The spray drying equipment comprises a spray drying tower, an atomizer and a heating system, wherein the atomizer is arranged in the center of the top of the spray drying tower; an inlet of the heating system is used for inputting external air, an outlet of the heating system is used for conveying hot air into the spray drying tower, and the temperature of the hot air conveyed by the heating system is in a decreasing trend from the center of the spray drying tower to the tower wall of the spray drying tower. In the drying process of the spray drying equipment, the heating temperature at the center of the spray drying tower is higher than the heating temperature near the tower wall of the spray drying tower, the high heating temperature at the center of the spray drying tower can guarantee the drying degree of materials, and the low heating temperature near the tower wall of the spray drying tower can further dry the materials and also can guarantee the drying degree of the materials. And meanwhile, the temperature of the material cannot reach the glass-transition temperature, so that the aim of inhibiting the hot-melt wall sticking phenomenon is fulfilled.

Description

Technical Field

[0001] The invention relates to the technical field of material drying, in particular to a spray drying device. Background Art

[0002] Spray drying equipment uses an atomizer to disperse the liquid into fine droplets, and quickly evaporates the solvent in the hot drying medium to form a dry powder product. It is mainly composed of a feeding system, an atomization system, a hot air system, and a collecting system. Spray drying equipment has the advantages of simple operation, high drying efficiency, less damage to effective ingredients, and uniform and fine powder obtained. It is widely used in material drying occasions.

[0003] For some materials containing sugar components (for example, most Chinese medicine extracts contain polysaccharides), their glass transition temperature is low. When using existing spray drying equipment to dry sugar-containing materials, hot melt and wall adhesion are likely to occur during the drying process, often causing partial carbonization, heat loss of effective ingredients, high heat loss and power consumption, and difficulty in equipment cleaning, which interrupts the spray drying operation and seriously affects production efficiency.

[0004] Therefore, how to alleviate the phenomenon of hot melting and wall sticking of sugar-containing materials during the drying process has become a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a spray drying equipment to solve the technical problems existing in the prior art that sugar-containing materials are prone to hot melting and wall adhesion during the drying process, resulting in partial carbonization, heat loss of effective ingredients, high heat loss and power consumption, and difficulty in equipment cleaning.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A spray drying device comprises a spray drying tower, an atomizer and a heating system, wherein:

[0008] The atomizer is arranged at the center of the top of the spray drying tower;

[0009] The inlet of the heating system is used to input external air, and the outlet of the heating system is used to transport hot air into the spray drying tower. The temperature of the hot air transported by the heating system tends to decrease from the center of the spray drying tower to the tower wall of the spray drying tower.

[0010] Further, the heating system includes at least two groups of heating components, each group of the heating components includes a first fan, a first heater and an annular air duct connected in sequence through a pipeline, wherein the annular air duct is arranged at the top of the spray drying tower, and an air outlet facing the inside of the spray drying tower is provided on the annular air duct;

[0011] The annular air ducts in at least two groups of the heating components are sequentially sleeved from the center of the spray drying tower to the tower wall of the spray drying tower.

[0012] Furthermore, an air volume sensor and / or a temperature sensor and / or a pressure sensor is provided on the pipeline of each group of the heating components.

[0013] Furthermore, the heating system comprises an annular air duct, and an air outlet facing the spray drying tower is formed between the lower ends of the inner annular wall and the outer annular wall of the annular air duct;

[0014] The outer ring wall of the annular air duct includes a plurality of first petals sequentially distributed along the circumference of the annular air duct, and the plurality of first petals can be opened or closed as the air pressure in the annular air duct changes.

[0015] Furthermore, the annular air duct further comprises an intermediate ring plate, wherein the intermediate ring plate is located between the outer ring wall and the inner ring wall and is in contact with the outer ring wall;

[0016] The intermediate ring plate includes a plurality of second petals sequentially distributed along the circumference of the annular air duct, and the second petals are staggered with the first petals.

[0017] Furthermore, when the drying effect of the material needs to be improved, the rotation speed of the atomizer is kept unchanged and the air outlet of the annular air duct is enlarged;

[0018] When the atomization effect of the material needs to be improved, the rotation speed of the atomizer is increased and the air outlet of the annular air duct is reduced;

[0019] When the material floats upward after atomization and drying, the air outlet of the annular air duct is reduced.

[0020] Furthermore, it also includes a material collection system, which includes a cyclone separator and a second fan connected through a pipeline, and the inlet of the cyclone separator is connected to the discharge port at the bottom of the spray drying tower;

[0021] The number of the cyclone separators is one or more; when the number of the cyclone separators is multiple, the multiple cyclone separators are connected head to tail in sequence, and the inlet air temperature of the multiple cyclone separators tends to decrease from the head end to the tail end.

[0022] Further, a second heater is provided on the pipeline between at least one of the cyclone separators and the second fan;

[0023] And / or, the spray drying tower includes an inner shell and an outer shell nested inside and outside, a cooling interlayer is formed between the outer shell and the inner shell, a cooling medium is provided in the cooling interlayer, and the cooling medium discharged from the cooling interlayer can heat the inlet air of at least one of the cyclone separators.

[0024] Furthermore, a pressure sensor is provided at the inlet of the cyclone separator;

[0025] And / or, a temperature sensor and / or a humidity sensor is provided on the pipeline between the cyclone separator and the spray drying tower;

[0026] And / or, a temperature sensor and / or an air volume sensor is provided on the pipeline between the cyclone separator and the second fan.

[0027] Furthermore, the material collecting system further comprises one or more cyclone catchers, the cyclone catchers correspond to the cyclone separators one by one, and the cyclone catchers are connected to the air outlets of the corresponding cyclone separators.

[0028] Furthermore, the spray drying tower comprises an inner shell and an outer shell which are nested inside and outside, a cooling interlayer is formed between the inner shell and the outer shell, and the cooling interlayer has an inlet for inputting a cooling medium and an outlet for discharging the cooling medium.

[0029] Furthermore, a heat exchange system is also included, the heat exchange system includes a heat exchanger, the heat exchanger is provided with a first heat exchange channel and a second heat exchange channel, wherein:

[0030] The first heat exchange channel is connected end to end with the cooling interlayer to form a circulation loop;

[0031] The inlet of the second heat exchange channel is used to input external air, and the outlet of the second heat exchange channel is connected to the inlet of the heating system.

[0032] Furthermore, it also includes a purge system, which includes a third fan and a hollow purge rod connected by a pipeline, wherein the hollow purge rod is arranged in the spray drying tower, and the hollow purge rod is provided with a plurality of through holes on one side of the tower wall of the spray drying tower.

[0033] Furthermore, it also includes a dehumidifier, the inlet of the dehumidifier is used to input external air, and the outlet of the dehumidifier is connected to the inlet of the heating system.

[0034] Beneficial effects of the present invention:

[0035] The spray drying equipment provided by the present invention comprises a spray drying tower, an atomizer and a heating system, wherein: the atomizer is arranged at the top center of the spray drying tower; the inlet of the heating system is used to input outside air, the outlet of the heating system is used to transport hot air into the spray drying tower, and the temperature of the hot air transported by the heating system tends to decrease from the center of the spray drying tower to the tower wall of the spray drying tower. During the drying process of the spray drying equipment, the heating temperature at the center of the spray drying tower is greater than the heating temperature near the tower wall of the spray drying tower, wherein the higher heating temperature at the center of the spray drying tower can ensure the drying degree of the material, and the lower heating temperature near the tower wall of the spray drying tower can further dry the material, and at the same time effectively control the temperature of the material so that the temperature of the material does not reach the glass transition temperature, thereby achieving the purpose of suppressing the hot melt type wall sticking phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic diagram of the structure of a spray drying device provided in Example 1 of the present invention;

[0038] Figure 2 A schematic diagram of the top view of the atomizer, multi-stage annular air duct and spray drying tower provided in the first embodiment of the present invention;

[0039] Figure 3 A schematic diagram of an axial cross-section of an annular air duct provided in Embodiment 1 of the present invention;

[0040] Figure 4 A schematic diagram of a three-dimensional structure of an annular air duct provided in Embodiment 1 of the present invention;

[0041] Figure 5 A schematic diagram of a three-dimensional structure of another annular air duct provided in the first embodiment of the present invention;

[0042] Figure 6 A schematic diagram of the structure of a spray drying device provided in Embodiment 2 of the present invention;

[0043] Figure 7 A schematic diagram of the structure of a spray drying device provided in Embodiment 3 of the present invention;

[0044] Figure 8 This is a schematic diagram of the structure of the spray drying equipment provided in Example 4 of the present invention.

[0045] icon:

[0046] 1- spray drying tower; 11- cooling interlayer;

[0047] 2- Atomizer;

[0048] 3-heating system; 31-heating assembly; 311-first fan; 312-first heater; 313-annular air duct; 3131-first petal; 3132-second petal;

[0049] 4- material collecting system; 41- second fan; 42- second heater; 43- cyclone separator; 44- cyclone collector;

[0050] 5-heat exchange system; 51-heat exchanger; 52-circulation pump;

[0051] 6-purge system; 61-third fan; 62-third heater; 63-hollow purge rod;

[0052] 7- Dehumidifier;

[0053] 8- Feed pump. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0056] It should be noted that in the description of the present invention, the terms "connection" and "installation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or connected through an intermediate medium; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In view of the phenomenon that sugar-containing materials are prone to hot melting and wall adhesion during the drying process, the present invention provides a spray drying device, referring to Figure 1 The equipment comprises a spray drying tower 1, an atomizer 2 and a heating system 3, wherein:

[0058] The atomizer 2 is arranged at the top center of the spray drying tower 1;

[0059] The inlet of the heating system 3 is used to input external air, and the outlet of the heating system 3 is used to transport hot air into the spray drying tower 1, and the temperature of the hot air transported by the heating system 3 tends to decrease from the center of the spray drying tower 1 to the tower wall of the spray drying tower 1.

[0060] In the process of drying materials in the spray drying equipment provided by the present application, the materials are injected into the atomizer 2 through the pipeline and then atomized into fine droplets. The droplets are ejected from the center of the atomizer 2 to the tower wall, and then ejected from top to bottom to the bottom of the tower; at the same time, the heating system 3 transports hot air for drying materials into the spray drying tower 1. Since the temperature of the hot air transported by the heating system 3 decreases from the center of the spray drying tower 1 to the tower wall of the spray drying tower 1, the heating temperature at the center of the spray drying tower 1 (that is, the heating temperature close to the atomizer 2) is higher, and the heating temperature near the tower wall of the spray drying tower 1 (that is, the heating temperature away from the atomizer 2) is lower. Accordingly, the evaporation rate of the droplets in the spray drying tower 1 decreases from the center of the spray drying tower 1 to the tower wall of the spray drying tower 1. After the material is sprayed out by the atomizer 2, it evaporates violently at the center of the spray drying tower 1, and the water content is sharply reduced. At this time, the evaporation of water absorbs heat and the material temperature is relatively low. After the material moves to the vicinity of the wall of the spray drying tower 1, it continues to be dried near the wall of the spray drying tower 1. Because the heating temperature near the wall of the spray drying tower 1 is relatively low, the material temperature will not be too high and will not reach the glass transition temperature, thereby not causing hot melting and wall adhesion.

[0061] It should be noted that the heating temperature of each area in the spray drying tower 1 is adjusted according to different materials, and is not limited here. The heating temperature of each area should allow the material to be fully dried and the material temperature to not reach the glass transition temperature, thereby ensuring the dryness of the material while avoiding the phenomenon of hot melting and wall adhesion.

[0062] In summary, during the drying process of the spray drying equipment provided in the present application, the heating temperature at the center of the spray drying tower 1 is greater than the heating temperature near the wall of the spray drying tower 1, wherein the higher heating temperature at the center of the spray drying tower 1 can ensure the degree of dryness of the material, while the lower heating temperature near the wall of the spray drying tower 1 can further dry the material and effectively control the temperature of the material, thereby achieving the purpose of suppressing the hot melt type wall sticking phenomenon.

[0063] Furthermore, the spray drying equipment provided in the present application also includes a feed pump 8, a material receiving system 4, a dehumidifier 7, a power distribution cabinet and a control interface, wherein:

[0064] The feed pump 8 is connected to the inlet of the atomizer 2 through a pipeline, and is used to inject the material into the atomizer 2;

[0065] The material collection system 4 is connected to the discharge port at the bottom of the spray drying tower 1 and is used for cooling and collecting materials;

[0066] The inlet of the dehumidifier 7 is used to input outside air, and the outlet of the dehumidifier 7 is connected to the inlet of the heating system 3 and / or the inlet of the material receiving system 4, which is used to dehumidify the air entering the equipment, increase the moisture carrying capacity of the hot air in the spray drying tower 1, and facilitate the spray drying of the material;

[0067] The power distribution cabinet and control interface are used to monitor and control the equipment.

[0068] The present invention is described in detail below with reference to several specific embodiments.

[0069] Embodiment 1

[0070] Reference Figure 1 and Figure 2 In this embodiment, the heating system 3 includes at least two groups of heating components 31, each group of heating components 31 includes a first fan 311, a first heater 312 and an annular air duct 313 which are sequentially connected through pipelines, wherein the annular air duct 313 is arranged at the top of the spray drying tower 1, and an air outlet facing the inside of the spray drying tower 1 is provided on the annular air duct 313;

[0071] The annular air ducts 313 in at least two groups of heating components 31 are sequentially arranged from the center of the spray drying tower 1 to the tower wall of the spray drying tower 1 .

[0072] In this embodiment, the air inlet of the first fan 311 is also the inlet of the heating system 3. The air inlet of the first fan 311 is connected to the outlet of the dehumidifier 7 through a pipeline. The air outlet of the first fan 311, the first heater 312 and the air inlet of the annular air duct 313 are connected in sequence; the air outlet of the annular air duct 313 is also the outlet of the heating system 3, which faces the inside of the spray drying tower 1, so that dry hot air can be input into the spray drying tower 1.

[0073] As one structural form of the air outlet of the annular air duct 313, the bottom of the annular air duct 313 is open to form an annular air outlet. As another structural form of the air outlet of the annular air duct 313, a plurality of hole-shaped air outlets are provided on the bottom wall of the annular air duct 313 and are distributed at intervals along the circumference of the annular air duct 313.

[0074] In at least two groups of heating components 31, the annular air duct 313 close to the atomizer 2 is a first-level heating air duct, and the remaining annular air ducts 313 are second-level heating air ducts to N-level heating air ducts in the direction away from the atomizer 2. The temperature of the hot air in each level of heating air duct can be reduced step by step, or the temperature of the hot air in some levels of heating air ducts can remain unchanged.

[0075] Take the embodiment in which the heating system 3 includes two sets of heating components 31 as an example. Figure 1 and Figure 2 As shown, the annular air duct 313 in the two groups of heating components 31 are respectively the first-level heating air duct and the second-level heating air duct. The atomizer 2, the first-level heating air duct and the second-level heating air duct are arranged in sequence from the inside to the outside, and the hot air temperature in the first-level heating air duct is greater than the hot air temperature in the second-level heating air duct. Since the heating temperature of the first-level heating air duct is relatively high, the droplets just sprayed from the atomizer 2 are instantly dried into fine powder by the hot air output from the first-level heating air duct, and the water evaporates and absorbs heat. At this time, the temperature of the material is relatively low; then the material is ejected horizontally from the center of the atomizer 2 to the tower wall, and is further heated by the second-level heating air duct. Since the heating temperature of the second-level heating air duct is relatively low, the temperature of the fine powder will not be too high, so that it will not cause hot melting and wall adhesion.

[0076] Continue to refer to Figure 1 , an air volume sensor and / or a temperature sensor and / or a pressure sensor is provided on the pipeline of each group of heating components 31. In this embodiment, an air volume sensor is provided at the air outlet of the first fan 311, a temperature sensor is provided at the air outlet of the first heater 312, and a pressure sensor is provided at the entrance of the annular air duct 313, so that the heating temperature at each level, the heating air volume and the air pressure in the annular air duct 313 can be controlled according to the actual production situation.

[0077] Optionally, a temperature sensor and a humidity sensor are provided in the spray drying tower 1, wherein the temperature sensor can detect the temperature in the tower in real time, and the humidity sensor can detect the moisture content of the material in the tower. The temperature in the tower and the moisture content of the material in the tower provide more accurate data support for the regulation of the heating temperature and air volume at each level, thereby realizing the dynamic regulation of the heating temperature and air volume at each level during the production process.

[0078] Reference Figure 3 and Figure 4 An air outlet toward the spray drying tower 1 is formed between the inner ring wall and the lower end of the outer ring wall of the annular air duct 313;

[0079] The outer ring wall of the annular air duct 313 includes a plurality of first petals 3131 sequentially distributed along the circumference of the annular air duct 313 . The plurality of first petals 3131 can open or close as the air pressure in the annular air duct 313 changes.

[0080] like Figure 3As shown, the outer annular wall of the annular air duct 313 includes a plurality of first petals 3131 sequentially distributed along the circumference of the annular air duct 313 , and the inner annular wall surface of the annular air duct 313 is a complete annular surface. Figure 3 The annular air duct 313 is specifically a primary heating air duct, and the inner annular wall surface of the primary heating air duct can be formed by the outer peripheral surface of the atomizer 2. Figure 4 As shown, the inner ring wall of the annular air duct 313 can also be composed of an annular plate. With the above annular air duct 313, as the pressure of the compressed air in the annular air duct 313 increases, the annular air duct 313 expands outward, and the multiple first petals 3131 open; conversely, as the pressure of the compressed air in the annular air duct 313 decreases, the annular air duct 313 contracts inward, and the multiple first petals 3131 close. The air outlet of the annular air duct 313 expands or shrinks as the multiple first petals 3131 open or close, thereby achieving the purpose of adjusting the air outlet of the annular air duct 313. The air outlet of the annular air duct 313 is also the air inlet of the spray drying tower 1. By adjusting the size of the air outlet of the annular air duct 313, the air intake volume and air intake speed of the spray drying tower 1 can be adjusted accordingly.

[0081] Reference Figure 5 On the basis of the above structure, the annular air duct 313 further includes an intermediate ring plate, which is located between the outer ring wall and the inner ring wall and fits with the outer ring wall; the intermediate ring plate includes a plurality of second petals 3132 sequentially distributed along the circumference of the annular air duct 313, and the second petals 3132 are staggered with the first petals 3131. The plurality of second petals 3132 also open or close with the change of air pressure in the annular air duct 313, and because the second petals 3132 are staggered with the first petals 3131, when the annular air duct 313 expands outward, the second petals 3132 can make up for the gap between the two adjacent first petals 3131, thereby preventing the air in the annular air duct 313 from flowing out from the side, and ensuring the integrity of the air outlet of the annular air duct 313.

[0082] According to Bernoulli's principle, by reducing the air outlet of the annular air duct 313, the air flow rate will increase accordingly, and conversely, by expanding the air outlet of the annular air duct 313, the air flow rate will decrease accordingly. When the rotation speed of the atomizer 2 remains unchanged, appropriately expanding the air outlet of the annular air duct 313 can extend the drying time of the material in the tower and make the material dry more fully; when the rotation speed of the atomizer 2 is increased and the air outlet of the annular air duct 313 is appropriately reduced, the atomization degree can be improved and the droplet speed can be effectively slowed down to avoid the semi-wet type of wall adhesion, and the drying can be more fully achieved; appropriately reducing the air outlet of the annular air duct 313 can also inhibit the powdered material from floating upward and avoid the powdered material from returning to the top. Therefore, by controlling the air pressure in the annular air duct 313, the opening and closing degree of the air outlet of the annular air duct 313 can be adjusted, thereby controlling the flow rate and flow direction of the dry hot air, thereby improving the drying behavior of the material.

[0083] Taking the Chinese medicine extract with a heavier texture as an example, when the drying effect of the extract needs to be improved, the rotation speed of the atomizer 2 remains unchanged, and the outlet of the annular air duct 313 is appropriately enlarged. At this time, the air flow rate is reduced, the drying time of the extract in the tower is extended, and the drying is more complete. If the atomization effect of the extract is improved, the rotation speed of the atomizer 2 is increased, and the initial speed of the extract droplets away from the atomizer is accelerated; and because the extract is heavier and the tower diameter is smaller, it is very easy to produce semi-wet wall adhesion. At this time, the outlet of the annular air duct 313 can be appropriately reduced to increase the flow rate of the hot air in the horizontal direction toward the atomizer, which can effectively slow down the droplet speed, avoid semi-wet wall adhesion, and dry more completely. Taking the lighter Chinese medicine extract as an example, after the extract is atomized and dried, it is very easy to float upward, causing the atomizer to return to the top. As time goes by, the return to the top becomes more severe, seriously affecting the atomization effect of the extract, affecting experiments and production. If the air outlet of the annular air duct 313 is appropriately reduced, the air flow rate is increased, and the hot air flow rate in the vertical direction is increased, the extract powder is suppressed from floating upward, avoiding the extract powder returning to the top, and ensuring experiments and production.

[0084] The following is a specific example to illustrate the adjustment process of the air outlet of the annular air duct 313. Figure 3 , Figure 3 In the embodiment shown, the annular air duct 313 is specifically a first-level heating air duct, and the spray port of the atomizer 2 is located below the air outlet of the annular air duct 313; taking the Chinese medicine extract as an example, the density of the Chinese medicine extract is 1.08-1.12g / cm3, the solid content is 15-40%, and the properties of the Chinese medicine extract are relatively complex, and there is no obvious corresponding relationship between its density and solid content. The adjustment process of the air outlet of the annular air duct 313 is as follows:

[0085] The opening and closing degree of the air outlet of the annular air duct 313 (i.e., the air inlet of the spray drying tower 1) is evaluated by the size of the horizontal angle α° of the outer ring wall of the annular air duct 313. To ensure that the hot air can fully contact the extract droplets, the adjustment range of the horizontal angle α° is 45° to 90°. The reason for setting this angle range is: when the horizontal angle α° is 45°, the vertical distance and horizontal distance between the center point of the spray port of the atomizer 2 and the outer edge of the air outlet of the annular air duct 313 are roughly equal. At this time, if the horizontal angle α° continues to be reduced, the wind flowing out of the air outlet of the annular air duct 313 may be blocked by the atomizer 2 and cannot enter the spray drying tower 1 normally; if the horizontal angle α° is greater than 90°, a gap will appear in the outer ring wall of the annular air duct 313, resulting in an incomplete air outlet;

[0086] The horizontal angle α° is 60° in the initial state. Taking a Chinese medicine extract with a density of 1.08 g / cm3 and a solid content of approximately 20% as an example, since the extract has a thin texture, the droplets formed are small in size and small in mass, and are very easy to float and fly. They are electrostatically adsorbed on the air outlet of the annular air duct 313 and the upper part of the atomizer 2, and continue to grow larger and thicker, seriously affecting the air intake and atomization effect of the spray drying tower 1. To address this phenomenon, the horizontal angle α° is reduced from 60° to 45°. According to the Bernoulli principle, since the air outlet of the annular air duct 313 is reduced and the wind speed is increased, the droplets are subjected to a greater downward thrust, the tendency to float upward is suppressed, and the problem of returning to the top is improved.

[0087] Taking a Chinese medicine extract with a density of 1.12g / cm3 and a solid content of approximately 35% as an example, due to the thick texture of the extract, the droplets formed are larger in size and mass, and are easier to fall in the vertical direction. The drying time in the spray drying tower 1 is short, and it is very easy to be insufficiently dried, forming a semi-wet sticky wall; in view of this phenomenon, the horizontal angle α° is enlarged from 60° to 80°. According to the Bernoulli principle, due to the expansion of the air outlet of the annular air duct 313, the wind speed is reduced, the downward thrust of the droplets is reduced, the drying time in the spray drying tower 1 is extended, and the drying is more complete, which can effectively improve the semi-wet sticky wall problem. It should be noted that the above example description is only to better illustrate the role of the spray drying tower 1 using the adjustable air intake method. Since the opening and closing degree of the air outlet of the annular air duct 313 is affected by the comprehensive influence of multiple factors such as the rotation speed of the atomizer 2, the feed speed, the fan power, and the extract properties, a comprehensive analysis is still required in the specific experimental production process. In addition, the horizontal angle α° may also be less than 45°. For example, the adjustment range of the horizontal angle α° may also be expanded to 20° to 90°. This angle range may be adaptively adjusted according to actual needs.

[0088] In summary, reasonable regulation of the opening and closing degree of the air outlet of the annular air duct 313 can not only improve the drying behavior of the Chinese medicine extract, but also overcome the wall sticking problem caused by the small tower diameter due to site limitations, thereby improving the applicability of the spray drying equipment.

[0089] Continue to refer to Figure 1 In this embodiment, the spray drying tower 1 includes an inner shell and an outer shell nested inside and outside, and a cooling interlayer 11 is formed between the outer shell and the inner shell. The cooling interlayer 11 has an inlet for inputting a cooling medium and an outlet for discharging the cooling medium, so that the circulating cooling medium can be transported in the cooling interlayer 11. The cooling medium can be a gas or a liquid, which is not limited here. By providing the cooling interlayer 11, the tower wall can be cooled, and the phenomenon of material sticking to the wall can be further suppressed.

[0090] Further, the collecting system 4 includes a second fan 41 and a cyclone separator 43 connected by a pipeline, and the inlet of the cyclone separator 43 is connected to the discharge port at the bottom of the spray drying tower 1. Specifically, the air inlet of the second fan 41 is connected to the outlet of the dehumidifier 7 through a pipeline, and the air outlet of the second fan 41 is connected to the inlet of the cyclone separator 43 through a pipeline, so that dry gas can be transported into the cyclone separator 43. The collecting system 4 also includes a cyclone catcher 44, which is connected to the air outlet of the cyclone separator 43 and is used to further collect the materials in the cyclone discharged from the cyclone separator 43.

[0091] Optionally, a pressure sensor is provided at the inlet of the cyclone separator 43;

[0092] And / or, a temperature sensor and / or a humidity sensor is provided on the pipeline between the cyclone separator 43 and the spray drying tower 1;

[0093] And / or, a temperature sensor and / or an air volume sensor is provided on the pipeline between the cyclone separator 43 and the second fan 41 .

[0094] The above sensors can detect signals such as material humidity, material temperature, air volume, air inlet temperature, etc. entering the cyclone separator 43, so as to monitor and adjust the working parameters of the equipment.

[0095] Embodiment 2

[0096] This embodiment is an extension solution based on the first embodiment.

[0097] Taking the extract powder as an example, it is found in the actual experimental production process that after the extract powder passes through the cyclone separator 43, a small amount of water vapor will remain in the extract powder, and the extract powder temperature is relatively high. If the cold air temperature is too low, and the difference between the extract powder temperature and the cold air temperature is too large, the residual water vapor condenses and causes the extract powder to absorb moisture and stick to the wall and agglomerate. If the cold air temperature is increased, although the condensation of the residual water vapor can be suppressed, the extract powder is not cooled sufficiently, and the heat accumulates in the powder collecting cylinder, and the extract powder is at risk of overheating and melting.

[0098] Based on the above problems, refer to Figure 6 In this embodiment, the collecting system 4 includes at least two cyclone separators 43 connected end to end in sequence, and the inlet air temperature of at least two cyclone separators 43 tends to decrease from the head end to the tail end.

[0099] In the above structure, the multiple cyclone separators 43 are first-stage separators, second-stage separators, and N-stage separators from the head end to the tail end; the inlet of the cyclone separator 43 at the head end is connected to the discharge port at the bottom of the spray drying tower 1; in two adjacent cyclone separators 43, the discharge port at the bottom of the upper cyclone separator 43 is connected to the inlet of the lower cyclone separator 43. The material is cooled in the first stage, second stage, and N stages in sequence by adopting the structure of the multi-stage separator, and the cooling temperature is gradually reduced or tends to decrease. By controlling the temperature difference between the inlet air and the feed of each stage of the cyclone separator 43 within the set range, the condensation of water vapor is suppressed, and the material temperature is effectively controlled, so that the moisture absorption and agglomeration of the extract powder can be effectively suppressed, the extract powder can be fully cooled, and the risk of overheating and melting of the extract powder can be avoided.

[0100] On the basis of the above structure, the collecting system 4 also includes at least two cyclone collectors 44 and at least two second fans 41, wherein: the cyclone collectors 44 correspond one-to-one to the cyclone separators 43, and the cyclone collectors 44 are connected to the air outlets of the corresponding cyclone separators 43; the second fans 41 correspond one-to-one to the cyclone separators 43, and the second fans 41 are connected to the inlets of the corresponding cyclone separators 43 through pipelines.

[0101] It should be noted that providing multiple second fans 41 is conducive to accurately controlling the air intake of each cyclone separator 43. In other embodiments, only one second fan 41 may be provided, and multiple cyclone separators 43 are supplied with air by the same second fan 41.

[0102] In this embodiment, a temperature sensor and a humidity sensor are provided on the pipeline between the cyclone separator 43 and the spray drying tower 1, and a temperature sensor and an air volume sensor are provided on the pipeline between the cyclone separator 43 and the second fan 41, so that the temperature difference between the inlet air and the feed of each stage of the cyclone separator 43 and the degree of dryness of the material can be detected in real time, so that the temperature difference between the inlet air and the feed of each stage of the cyclone separator 43 is controlled within an appropriate range, and at the same time, the material temperature in each stage of the cyclone separator 43 does not exceed the glass transition temperature of the material, thereby realizing dynamic regulation.

[0103] Continue to refer to Figure 6, a second heater 42 is provided between at least one cyclone separator 43 and the second fan 41. That is, the second heater 42 may be provided only between one or more of the cyclone separators 43 and the second fan 41, or a second heater 42 may be provided between each cyclone separator 43 and the second fan 41. Since the temperature of the material entering the cyclone separator 43 decreases step by step, the inlet air of the cyclone separator 43 at the tail end usually does not need to be heated, so the cyclone separator 43 at the tail end may not be connected to the second heater 42. Exemplarily, the number of cyclone separators 43 is two and they are the first separator and the second separator respectively, the second fan 41, the second heater 42 and the first separator are connected in sequence through pipelines, and the second fan 41 and the second separator are connected through pipelines, that is, the second heater 42 is not provided between the second fan 41 and the second separator.

[0104] Continue to refer to Figure 6 The spray drying tower 1 includes an inner shell and an outer shell which are nested inside and outside, and a cooling interlayer 11 is formed between the outer shell and the inner shell. A circulating cooling medium is provided in the cooling interlayer 11, and the cooling medium discharged from the cooling interlayer 11 can heat the inlet air of at least one cyclone separator 43. Exemplarily, when the cooling medium in the cooling interlayer 11 is gas, the outlet of the cooling interlayer 11 is connected to the inlet of the second fan 41 corresponding to the first separator through a pipeline to increase the temperature of the gas entering the first separator, thereby achieving the purpose of energy saving; in addition, the outlet of the cooling interlayer 11 can also be connected to the inlet of the first fan 311 through a pipeline to preheat the gas entering the first fan 311.

[0105] Embodiment 3

[0106] This embodiment is an extended solution based on any of the above embodiments. Figure 7 The spray drying equipment provided in this embodiment also includes a purge system 6, which includes a third fan 61 and a hollow purge rod 63 connected by a pipeline, wherein the hollow purge rod 63 is arranged in the spray drying tower 1, and a through hole is opened on one side of the hollow purge rod 63 facing the tower wall of the spray drying tower 1.

[0107] Specifically, the hollow purge rod 63 extends from the bottom of the tower to the top of the tower along the tower wall, and a plurality of through holes are arranged at intervals along the length direction of the hollow purge rod 63 on the side of the hollow purge rod 63 facing the tower wall. The air inlet of the third fan 61 is connected to the outlet of the dehumidifier 7 through a pipeline, and the air outlet of the third fan 61 is connected to the bottom end of the hollow purge rod 63 through a pipeline. A third heater 62 is arranged on the pipeline between the third fan 61 and the hollow purge rod 63, and the air entering the hollow purge rod 63 is heated by the third heater 62, so that the hollow purge rod 63 blows dry and clean air toward the tower wall, promotes the flow of materials in the tower, and alleviates the phenomenon of materials sticking to the wall.

[0108] In this embodiment, an air volume sensor is provided at the air outlet of the third fan 61, and a temperature sensor is provided at the air outlet of the third heater 62, so as to monitor and regulate the purge gas.

[0109] Embodiment 4

[0110] This embodiment is an extended solution based on any of the above embodiments. Figure 8 The spray drying device provided in this embodiment further includes a heat exchange system 5, the heat exchange system 5 includes a heat exchanger 51, and the heat exchanger 51 is provided with a first heat exchange channel and a second heat exchange channel, wherein:

[0111] The first heat exchange channel is connected end to end with the cooling interlayer 11 to form a circulation loop;

[0112] The inlet of the second heat exchange channel is used to input external air, and the outlet of the second heat exchange channel is connected to the inlet of the heating system 3.

[0113] Specifically, the cooling medium is preferably a coolant, and a circulating pump 52 is provided on the first heat exchange channel, and the circulating pump 52 is used to circulate the cooling medium in the first heat exchange channel and the cooling interlayer 11 to quickly cool the tower wall. The inlet of the second heat exchange channel is connected to the outlet of the dehumidifier 7 through a pipeline, and the outlet of the second heat exchange channel is connected to each first fan 311, part of the second fan 41 and the third fan 61 through a pipeline, so that the cooling medium discharged from the cooling interlayer 11 can preheat the heating air intake, cooling air intake and purge air intake, so as to realize the secondary utilization of the waste heat generated by the equipment, and achieve the purpose of energy saving, emission reduction and production cost reduction.

[0114] Continue to refer to Figure 8 Taking the material as Chinese medicine extract as an example, the working process of the spray drying equipment provided in this embodiment is as follows:

[0115] Open the power distribution cabinet and start the spray drying equipment; turn on the dehumidifier 7, which provides dry and clean air for the entire equipment; turn on the first fan 311 and the first heater 312 to preheat the drying tower, and the two first heaters 312 are heated independently, thereby inputting the first-stage heated air with a higher temperature and the second-stage heated air with a lower temperature into the spray drying tower 1 respectively; turn on the circulation pump 52, the cooling water in the cooling interlayer 11 starts to circulate, and under the action of the heat exchanger 51, the cold air entering the equipment is preheated;

[0116] After the preheating is completed, the feed pump 8 is turned on, and the Chinese medicine extract is injected into the atomizer 2 through the pipeline, and then atomized into fine droplets; after the droplets are sprayed into the spray drying tower 1, they are first dried into fine powder by the primary heated air, and then continue to be dried by the secondary heated air in the process of being ejected horizontally from the center of the atomizer 2 to the tower wall. Since the temperature of the secondary heated air is relatively low, the temperature of the fine powder will not be too high, so the phenomenon of hot melting and wall adhesion will not occur; the dried fine powder is pushed by the airflow and spirals downward along the tower wall, and then the fine powder is mixed with the hot air, The water vapor is discharged from the bottom of the spray drying tower 1 and enters the primary separator; the primary cooling air is usually warm air, and the warm air is used to preliminarily cool the fine powder to avoid condensation of water vapor; then the fine powder enters the secondary separator, and the secondary cooling air is usually cold air, and the cold air is used to finally cool the fine powder. The fine powder is finally discharged from the discharge port at the bottom of the secondary separator and enters the powder collecting barrel; the cyclone discharged from the air outlet of the cyclone separator 43 enters the cyclone collector 44, and the powder in the cyclone is further collected by the cyclone collector 44 to improve the material yield;

[0117] After the process is finished, first turn off each heater, wait until the air inlet temperature of the two sets of heating components 31 drops below 80°C, then turn off the fan, circulation pump, atomizer, purge rod, dehumidifier and other mechanisms; finally turn off the power supply.

[0118] The working parameters of the above equipment can be adjusted according to the difference in the properties of the extract. For the setting of the opening and closing degree of the air outlet of the annular air duct 313, for materials with heavier textures, the compressed air pressure can be increased to expand the air outlet of the annular air duct 313; for materials with lighter textures, the compressed air pressure can be reduced to shrink the air outlet of the annular air duct 313. The setting of the heating temperature at each level, the cooling temperature at each level and the interlayer temperature needs to be adjusted according to the glass transition temperature of the material. The heating temperature at each level can adjust the power of each first fan 311 and the heating temperature of each first heater 312 according to the data of the air volume sensor and the temperature sensor; the cooling temperature at each level can also adjust the power of each second fan 41 and the heating temperature of the second heater 42; the temperature of the cooling medium in the cooling interlayer 11 is adjusted by adjusting the power of the circulating pump 52.

[0119] The use of the spray drying equipment provided in the present application can improve the hot melt wall adhesion problem during the spray drying of traditional Chinese medicine extracts, the moisture absorption problem in the material collection stage, and the problem of returning to the top and insufficient drying due to differences in the properties of the extracts, thereby improving product quality, reducing production energy consumption, and improving production efficiency and benefits.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spray drying device, characterized in that: The invention comprises a spray drying tower (1), an atomizer (2) and a heating system (3), wherein: The atomizer (2) is arranged at the center of the top of the spray drying tower (1); The inlet of the heating system (3) is used to input external air, and the outlet of the heating system (3) is used to transport hot air into the spray drying tower (1). The temperature of the hot air transported by the heating system (3) tends to decrease from the center of the spray drying tower (1) to the tower wall of the spray drying tower (1).

2. The spray drying equipment according to claim 1, characterized in that The heating system (3) comprises at least two groups of heating components (31), each group of the heating components (31) comprises a first fan (311), a first heater (312) and an annular air duct (313) which are sequentially connected through a pipeline, wherein the annular air duct (313) is arranged at the top of the spray drying tower (1), and an air outlet facing the inside of the spray drying tower (1) is provided on the annular air duct (313); The annular air ducts (313) in at least two groups of the heating components (31) are sequentially arranged from the center of the spray drying tower (1) to the tower wall of the spray drying tower (1).

3. The spray drying equipment according to claim 2, characterized in that An air volume sensor and / or a temperature sensor and / or a pressure sensor is provided on the pipeline of each group of the heating components (31).

4. The spray drying device according to any one of claims 1 to 3, characterized in that: The heating system (3) comprises an annular air duct (313), wherein an air outlet facing the inside of the spray drying tower (1) is formed between the lower ends of the inner annular wall and the outer annular wall of the annular air duct (313); The outer annular wall of the annular air duct (313) includes a plurality of first petals (3131) distributed in sequence along the circumference of the annular air duct (313), and the plurality of first petals (3131) can open or close as the air pressure in the annular air duct (313) changes.

5. The spray drying equipment according to claim 4, characterized in that The annular air duct (313) further comprises an intermediate ring plate, wherein the intermediate ring plate is located between the outer ring wall and the inner ring wall and is in contact with the outer ring wall; The intermediate ring plate comprises a plurality of second petals (3132) sequentially distributed along the circumference of the annular air duct (313), and the second petals (3132) and the first petals (3131) are distributed in an alternating manner.

6. The spray drying equipment according to claim 4, characterized in that When the drying effect of the material needs to be improved, the rotation speed of the atomizer (2) is kept unchanged and the air outlet of the annular air duct (313) is enlarged; When it is necessary to improve the atomization effect of the material, the rotation speed of the atomizer (2) is increased and the air outlet of the annular air duct (313) is reduced; When the material floats upward after atomization and drying, the air outlet of the annular air duct (313) is reduced.

7. The spray drying equipment according to any one of claims 1 to 3, characterized in that: It also includes a material collection system (4), the material collection system (4) includes a second fan (41) and a cyclone separator (43) connected through a pipeline, and the inlet of the cyclone separator (43) is connected to the discharge port at the bottom of the spray drying tower (1); The number of the cyclone separators (43) is one or more; when the number of the cyclone separators (43) is multiple, the multiple cyclone separators (43) are connected in sequence head to tail, and the inlet air temperature of the multiple cyclone separators (43) tends to decrease from the head end to the tail end.

8. The spray drying equipment according to claim 7, characterized in that A second heater (42) is provided on the pipeline between the second fan (41) and at least one of the cyclone separators (43); And / or, the spray drying tower (1) comprises an inner shell and an outer shell which are nested inside and outside, a cooling interlayer (11) is formed between the inner shell and the outer shell, a cooling medium is provided in the cooling interlayer (11), and the cooling medium discharged from the cooling interlayer (11) can heat the inlet air of at least one of the cyclone separators (43).

9. The spray drying equipment according to claim 7, characterized in that A pressure sensor is provided at the inlet of the cyclone separator (43); And / or, a temperature sensor and / or a humidity sensor is provided on the pipeline between the cyclone separator (43) and the spray drying tower (1); And / or, a temperature sensor and / or an air volume sensor is provided on the pipeline between the cyclone separator (43) and the second fan (41).

10. The spray drying equipment according to claim 7, characterized in that: The material collecting system (4) further comprises one or more cyclone collectors (44), wherein the cyclone collectors (44) correspond one to one with the cyclone separators (43), and the cyclone collectors (44) are connected to the air outlets of the corresponding cyclone separators (43).

11. The spray drying equipment according to any one of claims 1 to 3, characterized in that: The spray drying tower (1) comprises an inner shell and an outer shell which are nested inside and outside, a cooling interlayer (11) is formed between the inner shell and the outer shell, and the cooling interlayer (11) has an inlet for inputting a cooling medium and an outlet for discharging the cooling medium.

12. The spray drying equipment according to claim 11, characterized in that It also includes a heat exchange system (5), the heat exchange system (5) includes a heat exchanger (51), the heat exchanger (51) is provided with a first heat exchange channel and a second heat exchange channel, wherein: The first heat exchange channel and the cooling interlayer (11) are connected end to end to form a circulation loop; The inlet of the second heat exchange channel is used to input external air, and the outlet of the second heat exchange channel is connected to the inlet of the heating system (3).

13. The spray drying equipment according to any one of claims 1 to 3, characterized in that: The invention also comprises a purge system (6), wherein the purge system (6) comprises a third fan (61) and a hollow purge rod (63) which are connected via a pipeline, wherein the hollow purge rod (63) is arranged in the spray drying tower (1), and a plurality of through holes are opened on one side of the hollow purge rod (63) facing the tower wall of the spray drying tower (1).

14. The spray drying equipment according to any one of claims 1 to 3, characterized in that: It also comprises a dehumidifier (7), the inlet of the dehumidifier (7) is used to input outside air, and the outlet of the dehumidifier (7) is connected to the inlet of the heating system (3).

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