Multilayer fluidized bed dryer

Abstract

The utility model discloses a multilayer fluidized bed dryer which comprises a shell, a plurality of layers of air distribution plates are arranged in the shell, the air distribution plates are of a porous structure, partition plates are arranged on the upper surfaces of the air distribution plates to guide flow, and cooling pipelines are installed on the lower surfaces of the air distribution plates to adjust the temperature. A feeding hole is formed in the upper part of the shell, a high-temperature gas inlet is formed in the lower part of the shell, and wet materials and high-temperature gas flow reversely; an active regulation and control means is adopted, cooling pipelines are arranged on one or more bed layers, the temperature of the bed layers is autonomously regulated, and the conditions that the overall temperature field of a large dryer is difficult to regulate, and one or more bed layers are overheated or deviated to set working conditions are overcome; and meanwhile, the problem of equipment shutdown caused by material melting, air distribution plate blocking and bed blocking is solved, and the device is good in stability, capable of running for a long period and suitable for large-scale production.

Description

Technical Field

[0001] The utility model belongs to the technical field of dryers, and particularly relates to a multi-layer fluidized bed dryer. Background Art

[0002] The statements here only provide the background art related to the utility model, and do not necessarily constitute the prior art.

[0003] A fluidized bed, abbreviated as a fluid bed, is a reactor that uses a gas or liquid to pass through a granular solid layer to make the solid particles in a suspended motion state, and conducts a gas-solid phase reaction process or a liquid-solid phase reaction process.

[0004] In the prior art, it is proposed to apply the fluidized bed to the field of material drying. The fluidized drying bed is a kind of high-efficiency drying bed, which has the advantages of high heat transfer and mass transfer rates, high drying rate, high thermal efficiency, compact structure, low investment and maintenance costs, etc. For example, the Chinese utility model patent CN219454451U discloses a vertical fluidized drying bed, in which a high-temperature packing area is arranged in the middle part of the drying bed, and hot air is introduced into the bottom of the drying bed. The hot air drives the wet material to move upward into the high-temperature packing area, so that the dried material adsorbs on the packing in the high-temperature packing area; this structure of fluidized bed dryer is suitable for the separate material drying process. In the actual production process, the drying process is only one step in the whole process. For example, in the dehydration process of producing anhydrous magnesium chloride by dehydrating bischofite, the above-mentioned structure of fluidized bed dryer cannot cooperate with other devices to complete the whole process; in addition, the flow field and temperature field distribution in the above-mentioned dryer are uneven, which is easy to cause the accumulation of materials, local or even overheating of the whole bed layer, resulting in a dead bed, the shutdown of the dryer, and the need to open the manhole for manual material cleaning and then start up, resulting in a long replacement period. The short material cleaning period is time-consuming and laborious, which is very unfavorable to the production process of the whole process. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a multi-layer fluidized bed dryer, which can actively regulate the temperature field distribution in the fluidized bed dryer to avoid equipment shutdown problems caused by material melting, air distribution plate plugging, and dead bed.

[0006] To achieve the above purpose, the utility model is realized by the following technical solutions:

[0007] In a first aspect, an embodiment of the utility model provides a multi-layer fluidized bed dryer, which includes a housing. A multi-layer air distribution plate is arranged in the housing. The air distribution plate adopts a porous structure, and a partition plate is arranged on the upper surface of the air distribution plate for guiding the flow. A cooling pipeline is installed on the lower surface of the air distribution plate to adjust the temperature; a feed inlet is arranged at the upper part of the housing, and a high-temperature gas inlet is arranged at the lower part. The wet material and the high-temperature gas move in opposite directions.

[0008] As a further technical solution, the cooling pipes are distributed in an S shape at the bottom of the air distribution plate, and a cooling medium is introduced into the cooling pipes.

[0009] As a further technical solution, the partition plate is vertically arranged with respect to the air distribution plate, and the height of the partition plate is less than the distance between two adjacent layers of air distribution plates.

[0010] As a further technical solution, there are two partition plates, which are spaced apart by a set distance and arranged staggeredly, so as to form a Z-shaped channel between two layers of air distribution plates.

[0011] As a further technical solution, air holes are evenly distributed on the air distribution plate, the diameter of the air holes is 2 - 10 mm, and the hole opening rate is 30 - 40%.

[0012] As a further technical solution, an air outlet is arranged at the top of the housing, and a discharge outlet is arranged at the bottom. The air outlet is connected to a tail gas treatment device through a pipeline.

[0013] As a further technical solution, a demister is installed at the discharge outlet inside the housing.

[0014] As a further technical solution, the number of air distribution plates is 3 - 10 layers.

[0015] As a further technical solution, the air distribution plate is made of a steel plate with a thickness of 5 - 15 mm, and the partition plate is made of a steel plate with a thickness of 5 - 10 mm.

[0016] As a further technical solution, the feed inlet is connected to a material conveying device.

[0017] The beneficial effects of the above embodiments of the present invention are as follows:

[0018] The multi-layer fluidized bed dryer provided by the present invention adopts an active control means, and cooling pipes are arranged on one or several bed layers to independently adjust the temperature of the bed layer, overcoming the problem that it is difficult to adjust the overall temperature field of a large dryer, and the situation that one or several bed layers are overheated or deviate from the set working conditions; at the same time, it overcomes the problems of equipment shutdown caused by material melting, blockage of the air distribution plate, and dead bed, has good stability, can operate in a long cycle, and is suitable for large-scale production.

[0019] The multi-layer fluidized bed dryer provided by the present invention realizes the temperature control of each bed layer structure through the arranged cooling pipes, can change the temperature distribution in the fluidized bed dryer, and solves the problem that it is difficult to adjust the overall temperature field in a large dryer; at the same time, by arranging partition plates on the bed layer structure to play a certain guiding role, it can change the movement path and residence time of materials on each bed layer structure, and improve the material drying effect.

[0020] The multi-layer fluidized bed dryer provided by the present utility model adopts the countercurrent mode of wet materials and high-temperature gas in the fluidized bed dryer, which is beneficial to the full contact between the materials and the high-temperature air and realizes a better fluidization effect.

[0021] The multi-layer fluidized bed dryer provided by the present utility model can realize the corresponding process in a system composed of other devices, with a large adjustable range. It overcomes the problem of large fluctuations in the process parameters of the fluidized bed dryer and the inability to achieve long-term operation, which is beneficial to the long-term stable operation of the system. Brief Description of the Drawings

[0022] The attached drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model.

[0023] Figure 1 is a schematic structural diagram of the multi-layer fluidized bed dryer of the present utility model;

[0024] Figure 2 is a bottom view of the air distribution plate of the present utility model;

[0025] Figure 3 is a top view of the air distribution plate of the present utility model;

[0026] Figure 4 is a side view of the air distribution plate of the present utility model.

[0027] The schematic diagram is only for illustration;

[0028] Wherein, 1. housing; 2. air distribution plate; 201. cooling pipe; 202. partition plate; 203. air hole; 3. feed inlet; 4. high-temperature gas inlet; 5. air outlet; 6. discharge outlet; 7. demister; 8. material conveying device. Detailed Description of the Embodiments

[0029] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present utility model. Unless otherwise specified, all technical and scientific terms used in the present utility model have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs.

[0030] Embodiment 1

[0031] In a typical implementation manner of the present utility model, as Figures 1-4As shown in the figure, a multi-layer fluidized bed dryer is provided, which includes a housing 1. Inside the housing 1, a multi-layer air distribution plate 2 is provided. The air distribution plate 2 adopts a porous structure. A partition plate 202 is arranged on the upper surface of the air distribution plate 2 for flow guiding, and a cooling pipe 201 is installed on the lower surface of the air distribution plate 2 to adjust the temperature. An inlet 3 for feeding materials is arranged at the upper part of the housing 1, and an inlet 4 for high-temperature gas is arranged at the lower part. The wet materials and the high-temperature gas move in opposite directions.

[0032] A multi-layer air distribution plate 2 is arranged inside the housing 1 as the bed layer structure. By means of the arranged cooling pipe 201, the temperature control of each layer of the bed layer structure can be realized, the temperature distribution inside the fluidized bed dryer can be changed, and the problem that it is difficult to adjust the overall temperature field inside a large dryer is solved. At the same time, by arranging the partition plate 202 on the bed layer structure, a certain flow guiding effect is achieved, the movement path and residence time of the materials on each layer of the bed layer structure can be changed, and the drying effect of the materials is improved. At the same time, the wet materials and the high-temperature gas move in opposite directions inside the fluidized bed dryer, which is beneficial to the full contact between the materials and the high-temperature air and realizes a better fluidization effect.

[0033] As Figure 2 shown in the figure, the cooling pipe 201 is distributed in an S shape at the bottom of the air distribution plate 2. A cooling medium is introduced into the cooling pipe 201. The cooling medium can be air or water. By introducing a cooling medium with a set temperature into the cooling pipe 201, the regulation of the temperature field distribution inside the fluidized bed dryer is realized. One end of the cooling pipe 201 is the outlet of the cooling medium, and the other end is the inlet of the cooling medium. The outlet and the inlet of the cooling medium of the cooling pipe 201 are connected to the outside of the housing and are connected to a heat exchanger with a corresponding temperature, and the heat exchanger provides different temperatures for the cooling pipes 201 of different layers.

[0034] Optionally, cooling pipes are not arranged at the bottom of each air distribution plate. According to different dried materials, a suitable temperature field distribution can be selected, and then cooling pipes are arranged at the bottom of some air distribution plates and a cooling medium with a corresponding temperature is introduced.

[0035] As Figure 3 and Figure 4 shown in the figure, the partition plate 202 is arranged perpendicular to the air distribution plate 2, and the height of the partition plate 202 is less than the distance between two adjacent air distribution plates 2. Further, two partition plates 202 are provided, and a set distance is separated between the two partition plates 202 and they are arranged staggeredly, so as to form a Z-shaped channel between two layers of air distribution plates, which plays a role in guiding the flow of materials when the materials flow between two layers of air distribution plates 2, increases the residence time of the materials between two layers of air distribution plates, and improves the drying efficiency.

[0036] In this embodiment, one side of the partition plate 202 is in contact with the inner surface of the housing, and the other side is spaced apart from the inner surface of the housing by a certain distance to form a notch. The notches formed between the two partition plates 202 and the housing are arranged in a staggered manner, so as to form a Z-shaped channel between the two layers of air distribution plates in the horizontal direction.

[0037] In this embodiment, air holes 203 are uniformly distributed on the air distribution plate 2. The diameter of the air holes 203 is 2-10 mm, and the hole opening rate is 30-40%. By restricting the hole opening rate to 30-40%, it can not only ensure the uniform distribution of the air flow velocity, but also avoid causing a large pressure drop.

[0038] In this embodiment, an air outlet 5 is provided at the top of the housing 1, and a discharge port 3 is provided at the bottom. The air outlet 5 is connected to the tail gas treatment device through a pipeline. The waste gas discharged from the air outlet 5 enters the tail gas treatment device for purification, and the dried material discharged from the discharge port enters the next process.

[0039] In this embodiment, a demister 7 is installed at the discharge port inside the housing 1. The demister 7 performs demisting treatment on the waste gas before it is discharged. At the same time, the demister 7 can also perform demisting treatment on the demister inside the fluidized bed dryer.

[0040] In this embodiment, the number of the air distribution plates 2 is 3-10 layers. If the number of the air distribution plates 2 is too small, the residence time of the material in the fluidized bed dryer is short, and a good drying effect cannot be achieved. If the number of the air distribution plates 2 is too large, a large resistance will be generated, resulting in poor fluidization effect.

[0041] In this embodiment, the air distribution plate 2 is made of a steel plate with a thickness of 5-15 mm, and the partition plate 202 is made of a steel plate with a thickness of 5-10 mm.

[0042] In this embodiment, the feed inlet 3 is connected to the material conveying device 8. The wet material is conveyed into the fluidized bed dryer through the material conveying device for drying. The material conveying device can be a screw conveyor, a belt conveyor, a tube chain conveyor, or a pneumatic conveying device.

[0043] The working process of the multi-layer fluidized bed dryer provided in this embodiment is as follows:

[0044] The material conveying device 8 sends the wet material to be dried into the fluidized bed dryer through the feed inlet 3. At the same time, the high-temperature gas enters the fluidized bed dryer through the high-temperature gas inlet 4. The wet material passes through each bed layer from top to bottom, while the high-temperature gas passes through each bed layer from bottom to top. At the same time, the high-temperature gas has a drying effect and a fluidization effect on the wet material, realizing the drying of the wet material. During the drying process, by introducing a cooling medium into the cooling pipe 201 below the air distribution plate 2, the regulation of the temperature field distribution in the fluidized bed dryer is realized, so as to improve the drying efficiency and avoid the equipment shutdown problems caused by material melting, air distribution plate plugging, and dead bed.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-layer fluidized bed dryer, characterized in that: It includes a shell, in which a multi-layer air distribution plate is arranged. The air distribution plate adopts a porous structure. A partition is arranged on the upper surface of the air distribution plate for guiding the air. A cooling pipe is installed on the lower surface of the air distribution plate for adjusting the temperature. A feed port is arranged at the upper part of the shell, and a high-temperature gas inlet is arranged at the lower part, and the wet material and the high-temperature gas flow in opposite directions.

2. The multi-layer fluidized bed dryer according to claim 1, characterized in that The cooling pipeline is distributed in an S shape at the bottom of the air distribution plate, and a cooling medium is passed into the cooling pipeline.

3. The multi-layer fluidized bed dryer according to claim 1, characterized in that The partition is vertically arranged to the air distribution plate, and the height of the partition is smaller than the distance between two adjacent layers of air distribution plates.

4. The multi-layer fluidized bed dryer according to claim 3, characterized in that There are two partitions, which are spaced apart by a set distance and arranged alternately, so that a Z-shaped channel is formed between the two layers of air distribution plates.

5. The multi-layer fluidized bed dryer according to claim 1, characterized in that The air distribution plate is evenly distributed with air holes, the diameter of the air holes is 2-10 mm, and the opening rate is 30-40%.

6. The multi-layer fluidized bed dryer according to claim 1, characterized in that: An air outlet is arranged at the top of the shell, and a material outlet is arranged at the bottom. The air outlet is connected to the tail gas treatment device through a pipeline.

7. The multi-layer fluidized bed dryer according to claim 1, characterized in that: A demister is installed at the discharge port inside the shell.

8. The multi-layer fluidized bed dryer according to claim 1, characterized in that: The number of the air distribution plates is 3-10 layers.

9. The multi-layer fluidized bed dryer according to claim 1, characterized in that: The air distribution plate is made of 5-15mm steel plate, and the partition is made of 5-10mm steel plate.

10. The multi-layer fluidized bed dryer according to claim 1, characterized in that: The feed inlet is connected to a material conveying device.

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