A spray dryer and spray drying system for achieving a particle size distribution

Abstract

The utility model discloses a kind of spray driers and spray drying systems for realizing particle gradation, belong to spray drying technical field, for solving the problem that existing spray drier cannot simultaneously output different particle size particles in single drying and real-time control particle gradation. The spray drier and spray drying system of the utility model, including drying tower body, atomizer and hot air distributor;Drying tower body is equipped with flow guide area and mixing area, flow guide area includes at least two flow guide cavities, and the cavity opening between each flow guide cavity and another flow guide cavity is at least coincident. The number of atomizer is same with the number of flow guide area and the position corresponds with the position of flow guide area. Multiple atomizers are configured to be able to spray simultaneously and produce mist drop group with different average particle size. A hot air distributor is provided in each flow guide cavity. The utility model can simultaneously output different particle size particles in single drying and real-time control particle gradation, simplify process, reduce energy consumption and cost.

Description

Technical Field

[0001] This utility model belongs to the field of spray drying technology, and relates to a spray dryer and spray drying system for achieving particle size distribution. Background Technology

[0002] Spray drying is a highly efficient technology that disperses liquid or slurry materials into tiny droplets through an atomizer, which are then dried rapidly into powder upon contact with a hot air stream. It is widely used in industries such as chemical, food, pharmaceutical, and ceramics. Traditional spray dryers typically use a single atomizer (centrifugal, pressure, or airflow type), resulting in relatively concentrated droplet size distributions and a narrow particle size distribution range in the dried powder. In actual production, composite powder materials (lithium iron phosphate, sodium iron pyrophosphate, etc.), catalyst carriers, pharmaceutical microspheres, and other products require specific particle size distribution characteristics, meaning that particles of different size ranges are mixed in proportion to meet the product's requirements in terms of flowability, solubility, and bulk density.

[0003] Existing spray dryers mostly use a single atomizer (such as centrifugal, airflow, or pressure types), and their atomized particle size is limited by the atomizer type and operating parameters (such as rotation speed, airflow pressure, and feed rate), thus only producing dried particles with a single particle size distribution range. To obtain graded particles, it is usually necessary to mechanically mix powders of different batches and particle sizes, or to prepare particles of different sizes separately using multiple spray dryers with different parameters and then mix them. This process has problems such as cumbersome procedures, high investment costs, increased energy consumption, uneven mixing, easy introduction of impurities, and large footprint.

[0004] Currently, although some spray dryers offer dual atomizer replacement functionality (such as the ability to switch between centrifugal and airflow atomizers), they still require shutdown for disassembly and replacement, making it impossible to simultaneously produce particles of different sizes in a single drying cycle and difficult to achieve real-time control of particle size distribution. Utility Model Content

[0005] Based on the above analysis, the present invention aims to provide a spray dryer for achieving particle size distribution, so as to solve the technical problem that existing spray dryers cannot simultaneously produce particles of different sizes and control particle size distribution in real time during a single drying process.

[0006] The purpose of this utility model is mainly achieved through the following technical solutions.

[0007] The first aspect of this utility model provides a spray dryer for achieving particle size distribution, characterized in that it includes a drying tower, an atomizer, and a hot air distributor; the drying tower is provided with a guide zone and a mixing zone from top to bottom, the guide zone including at least two guide cavities; the atomizer is located at the top of the drying tower, the number of atomizers is the same as the number of guide zones and their positions correspond to the positions of the guide cavities; multiple atomizers are configured to spray simultaneously and generate droplet groups with different average particle sizes; each guide cavity is provided with an independent hot air distributor; the guide cavity is a vertically arranged incomplete cylindrical cavity with rectangular cavity openings on the sides, and the multiple cavity openings are interconnected.

[0008] Furthermore, the hot air distributor rotates in the same direction.

[0009] Furthermore, many of the atomizers are either centrifugal atomizers or pressure atomizers.

[0010] Furthermore, the multiple atomizers include at least one centrifugal atomizer and at least one pressure atomizer.

[0011] Furthermore, the curvature of the cavity opening is 30° to 60°.

[0012] Furthermore, the air inlet of the hot air distributor is arranged opposite to the cavity opening.

[0013] A second aspect of this invention provides a spray drying system for achieving particle size distribution, comprising a hot air system, a feeding system, and a spray dryer for achieving particle size distribution as described in any one of the first aspects of this invention.

[0014] Furthermore, the hot air system includes a gas diversion valve, which has at least two air outlets, each connected to the air inlet of a different hot air distributor.

[0015] Furthermore, the feeding system includes at least two feeding paths, each supplying liquid to a different atomizer.

[0016] Furthermore, each feeding path includes a feed pump, which is used to control the flow rate of the feeding path.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0018] 1. The spray dryer of this utility model, by setting up multiple atomizers that generate droplet groups with different average particle sizes, can flexibly adjust the particle size distribution and flow ratio of each droplet group according to the target gradation by combining independently controlled atomization parameters, thereby achieving real-time control of particle gradation. This eliminates the subsequent mixing process, simplifies the process, improves production efficiency, and reduces energy consumption and costs. By setting up multiple interconnected guide chambers, droplet groups of different particle sizes sprayed from multiple atomizers can collide and mix at the opening of the chamber under the action of multiple independent hot air distributors. This strengthens the interaction between particles, promotes the adhesion of fine particles to the surface of coarse particles or their co-aggregation, and simultaneously produces particles of different particle sizes in a single drying process. It can also effectively improve the density and gradation uniformity of the particles.

[0019] 2. The spray dryer of this utility model, by setting multiple hot air distributors with the same rotation direction, makes the hot air rotating in the same direction form a reverse shear force at the opening of the cavity, which further promotes the dynamic collision and fusion between the droplet groups, effectively avoiding particle agglomeration or wall settling, and making the gradation effect more ideal.

[0020] 3. The spray dryer of this utility model sets the arc of the cavity opening to 30° to 60°, which not only ensures that the airflows fully converge but also avoids eddy interference and improves the mixing uniformity.

[0021] 4. The spray dryer of this utility model, by arranging the air inlet of the hot air distributor opposite to the opening of the cavity, can form a symmetrical and uniform airflow field in the drying tower, effectively guiding the droplet groups of different particle sizes to flow through the cavity opening and fall into the mixing zone.

[0022] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the internal structure of the spray dryer according to Embodiment 1 of this utility model;

[0024] Figure 2 This is a top view of the spray dryer according to Embodiment 1 of this utility model;

[0025] Figure 3 This is a schematic diagram of the overall structure of the spray drying in Embodiment 2 of this utility model.

[0026] Figure label:

[0027] 1-Drying tower body; 11-Flow guiding zone; 111-Flow guiding cavity; 111A-First flow guiding cavity; 111B-Second flow guiding cavity; 1111-Cavity opening; 12-Mixing zone; 2-Atomizer; 2A-First atomizer; 2B-Second atomizer; 3-Hot air distributor; 3A-First hot air distributor; 31A-First air inlet; 3B-Second hot air distributor; 31B-Second air inlet;

[0028] 100-Hot air system; 101-Gas diversion valve; 101A-First air outlet; 101B-Second air outlet; 200-Feeding system; 200A-First feeding passage; 201A-First feed pump; 200B-Second feeding passage; 201B-Second feed pump; 300-Solid-liquid separation system. Detailed Implementation

[0029] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0030] Example 1

[0031] This embodiment provides a spray dryer for achieving particle size distribution, such as... Figure 1 As shown, the device includes a drying tower body 1, an atomizer 2, and a hot air distributor 3. The drying tower body 1 contains a guide zone 11 and a mixing zone 12 arranged sequentially from top to bottom. The guide zone 11 includes at least two guide chambers 111. The atomizer 2 is located at the top of the drying tower body 1, and the number of atomizers 2 is the same as the number of guide zones 11, with their positions corresponding to the positions of the guide chambers 111. Multiple atomizers 2 are configured to spray simultaneously and generate droplet clusters with different average particle sizes. Each guide chamber 111 contains an independent hot air distributor 3, and the multiple hot air distributors 3 rotate in the same direction. The guide chamber 111 is a vertically arranged, incomplete cylindrical cavity with rectangular cavity openings on its sides, and the cavity openings of the multiple guide chambers 111 are interconnected.

[0032] When producing products with particle size distribution, multiple atomizers operate synchronously, each generating droplet clusters of different particle sizes. As the droplet clusters generated by the multiple atomizers 2 enter the guide zone 11, they are guided by the rotating hot air generated by their respective hot air separators 3 within their respective guide chambers 111, moving downwards along a spiral trajectory and converging and mixing at the chamber openings. Since the multiple hot air separators 3 rotate in the same direction, the spiral airflow in the different guide chambers 111 rotates in opposite directions at the chamber openings, thus canceling out the airflow below the chamber openings. This allows the overall airflow within the drying tower 1 to flow downwards in a cyclone pattern into the mixing zone 12 for further mixing and drying, while also ensuring sufficient collision and adhesion between coarse and fine droplets. Because fine droplets, before being fully dried, adhere to the surface of coarse particles, or both coarse and fine particles fall together for drying, they form powder particles with ideal particle size distribution in the mixing zone 12. These particles then enter the gas-solid separation system for further drying, ultimately producing powder containing different particle sizes in a single process, achieving good powder gradation in real time.

[0033] The spray dryer of this embodiment, by setting up multiple atomizers 2 that generate droplet clusters with different average particle sizes, can flexibly adjust the particle size distribution and flow rate ratio of each droplet cluster according to the target gradation by combining independently controlled atomization parameters. This achieves real-time control of particle gradation, eliminating the subsequent mixing process, simplifying the process, improving production efficiency, and reducing energy consumption and costs. Simultaneously, by setting up multiple interconnected guide chambers 111, the droplet clusters of different particle sizes sprayed from multiple atomizers 2 can collide and mix at the chamber opening under the action of multiple independent hot air distributors 3. This strengthens the interaction between particles, promotes the adhesion of fine particles to the surface of coarse particles, or promotes co-aggregation. This not only simultaneously produces particles of different sizes in a single drying process but also effectively improves particle density and gradation uniformity. Furthermore, by setting up multiple hot air distributors 3 with the same rotation direction, the hot air rotating in the same direction forms a reverse shear force at the chamber opening, further promoting dynamic collision and fusion between droplet clusters, effectively avoiding particle agglomeration or wall settling, resulting in a more ideal gradation effect.

[0034] Considering the stability of the airflow within the guide zone 11, two to four atomizers 2 can be selected in this embodiment. The following explanation uses two atomizers 2 as an example.

[0035] like Figure 1 As shown, the atomizer 2 includes a first atomizer 2A and a second atomizer 2B. The first atomizer 2A and the second atomizer 2B are arranged side by side at the top of the drying tower 1 to form two droplet groups with a first average particle size distribution and a second average particle size distribution in the drying tower 1. There is a significant difference between the first average particle size and the second average particle size, so as to meet the customized needs of particle size distribution for different application scenarios.

[0036] In some embodiments, the first atomizer 2A and the second atomizer 2B are both centrifugal atomizers, and the atomizing disc diameter, rotation speed or toothed structure of the first atomizer 2A and the second atomizer 2B are different, thereby producing two different droplet groups.

[0037] In some embodiments, the first atomizer 2A and the second atomizer 2B are both pressure atomizers, and the nozzle orifice diameter or pressure of the first atomizer 2A and the second atomizer 2B are different, thereby producing two different droplet groups.

[0038] In some embodiments, the first atomizer 2A is a centrifugal atomizer and the second atomizer 2B is a pressure atomizer, thereby producing two different droplet groups.

[0039] This embodiment, by setting two atomizer combinations of different types or parameters, can precisely control the particle size distribution of two droplet groups, thereby obtaining an ideal particle size distribution curve and significantly improving the bulk density and compressibility of the powder. For example, the first atomizer is responsible for producing fine particles with a D50 of 5-20 μm, and the second is responsible for producing coarse particles with a D50 of 20-50 μm.

[0040] Correspondingly, such as Figure 1 and Figure 2 As shown, the flow guiding cavity 111 includes a first flow guiding cavity 111A and a second flow guiding cavity 111B. In some embodiments, to enable the airflows within the first flow guiding cavity 111A and the second flow guiding cavity 111B to come into contact with each other and form a stable mixing zone, the arc of the cavity opening between the first flow guiding cavity 111A and the second flow guiding cavity 111B is 30° to 60°. This arc design ensures sufficient convergence of airflows while avoiding eddy interference, thus improving mixing uniformity.

[0041] In some embodiments, such as Figure 1 and Figure 2 As shown, the hot air distributor 3 includes a first hot air distributor 3A and a second hot air distributor 3B. Preferably, the first air inlet 31A of the first hot air distributor 3A and the second air inlet 31B of the second hot air distributor 3B are respectively located on both sides of the drying tower body 1, so that hot air enters the first guide cavity 111A and the second guide cavity 111B from both sides of the drying tower body 1, thereby forming a symmetrical and uniform airflow field in the drying tower. This effectively guides droplet groups of different particle sizes to flow through the cavity opening 1111 and fall into the mixing zone 12, so that the droplet groups are simultaneously dried and dynamically aggregated under the wrapping of the high-temperature airflow. Finally, the droplet groups enter the gas-solid separation system 300 from the drying tower body 1 for further drying, thereby producing powder containing particles of different coarse and fine sizes in one go, achieving good gradation of the powder in real time.

[0042] Example 2

[0043] This embodiment provides a spray drying system for achieving particle size distribution, including a hot air system 100, a feeding system 200, and the spray dryer for achieving particle size distribution provided in Embodiment 1.

[0044] The following explanation uses the example of setting up two atomizers 2.

[0045] In some embodiments, such as Figure 3 As shown, the hot air system 100 includes a gas diversion valve 101, which includes a first air outlet 101A and a second air outlet 101B. The first air outlet 101A and the second air outlet 101B are connected to the first air inlet 31A of the first hot air distributor 3A and the second air inlet 31B of the second hot air distributor 3B through two hot air channels, respectively.

[0046] During operation, air passes through an air flow meter, air filter, pressure gauge, blower and air heater, and is divided into two hot air channels by a gas diversion valve 101. After entering the top of the drying tower 1 from both sides, the air enters the first hot air distributor 3A and the second hot air distributor 3B from the first air inlet 31A and the second air inlet 31B respectively, achieving uniform distribution.

[0047] In some embodiments, such as Figure 3 As shown, the feeding system 200 includes a first feeding passage 200A and a second feeding passage 200B, which respectively supply liquid to the first atomizer 2A and the second atomizer 2B. The first feeding passage 200A and the second feeding passage 200B each include a first feed pump 201A and a second feed pump 201B, which can respectively control the flow rate and concentration of the first feeding passage 200A and the second feeding passage 200B.

[0048] During operation, the first feed pump 201A and the second feed pump 201B draw liquid material from the material bins respectively. Flow meters on the first feed passage 200A and the second feed passage 200B can monitor the flow rate in real time. By adjusting the parameters of the first feed pump 201A and the second feed pump 201B, the spray intensity and droplet distribution density of the two droplet groups can be precisely controlled, achieving flexible adjustment of the final product's gradation. Optionally, the first feed pump 201A and the second feed pump 201B can also draw liquid material of different concentrations from the two material bins respectively. This allows for flexible adaptation to different product gradation requirements, enabling a single machine to produce multiple product specifications and expanding its application range.

[0049] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A spray dryer for achieving particle size distribution, characterized in that, It includes a drying tower (1), an atomizer (2), and a hot air distributor (3); The drying tower body (1) is provided with a flow guiding zone (11) and a mixing zone (12) from top to bottom. The flow guiding zone (11) includes at least two flow guiding cavities (111). The atomizer (2) is located at the top of the drying tower (1). The number of atomizers (2) is the same as the number of the guide zone (11) and their positions correspond to the positions of the guide cavity (111). Multiple atomizers (2) are configured to spray simultaneously and generate droplet groups with different average particle sizes. Each of the aforementioned flow guide cavities (111) is equipped with an independent hot air distributor (3); The flow guide cavity (111) is a vertically arranged incomplete cylindrical cavity with a rectangular cavity opening (1111) on the side, and the multiple cavity openings (1111) are connected to each other.

2. The spray dryer for achieving particle size distribution according to claim 1, characterized in that, The hot air distributor (3) rotates in the same direction.

3. The spray dryer for achieving particle size distribution according to claim 1, characterized in that, All of the atomizers (2) are centrifugal atomizers or pressure atomizers.

4. The spray dryer for achieving particle size distribution according to claim 1, characterized in that, The plurality of atomizers (2) include at least one centrifugal atomizer and at least one pressure atomizer.

5. The spray dryer for achieving particle size distribution according to any one of claims 1 to 4, characterized in that, The curvature of the cavity opening (1111) is 30° to 60°.

6. The spray dryer for achieving particle size distribution according to claim 5, characterized in that, The air inlet of the hot air distributor (3) is arranged opposite to the cavity opening (1111).

7. A spray drying system for achieving particle size distribution, characterized in that, It includes a hot air system (100), a feeding system (200), and a spray dryer for achieving particle size distribution as described in any one of claims 1 to 6.

8. The spray drying system for achieving particle size distribution according to claim 7, characterized in that, The hot air system (100) includes a gas diversion valve (110), which includes at least two air outlets, which are respectively connected to the air inlets of different hot air distributors (3).

9. The spray drying system for achieving particle size distribution according to claim 8, characterized in that, The feeding system (200) includes at least two feeding paths, which respectively supply liquid to different atomizers (2).

10. The spray drying system for achieving particle size distribution according to claim 9, characterized in that, Each of the feeding channels includes a feed pump, which is used to control the flow rate of the feeding channel.

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