Fluidized bed dryer and method for drying moist material in a fluidized bed dryer

Abstract

The present invention relates to a fluidized bed dryer (1) for drying wet materials using dry air, the fluidized bed dryer (1) comprising two or more drying zones (2) arranged vertically between a dry air supply connection (11) and an outlet (12) inside the fluidized bed dryer (1), the consecutive drying zones (2) being separated from each other by partition walls (3) with openings (4) to form a flow connection between the consecutive drying zones (2), and an additional dry air supply connection (13) connected to each drying zone (2), the additional dry air supply connection (13) being arranged to feed additional dry air to the drying zone (2). The present invention also relates to a method for drying wet materials in the fluidized bed dryer (1).

Description

Technical Field

[0001] The present invention relates to fluidized bed dryers, and more particularly to fluidized bed dryers as defined in the preamble of independent claim 1.

[0002] The present invention also relates to a method for drying wet materials in a fluidized bed dryer, and more particularly to a method as defined in the preamble of independent claim 11. Background Technology

[0003] Different types of fluidized bed dryers are known in the art. A typical fluidized bed dryer consists of a drying chamber in which material is floated to dry, and then the dried material is removed from the drying chamber. In most cases, fluidized bed dryers are designed for specific materials and specific needs, in which case the types of materials that can be dried in a fluidized bed dryer are very limited. The material to be dried may require a long drying time or a large space to dry, which determines the characteristics required of the fluidized bed dryer. In such cases, the large size of the fluidized bed dryer or its vertical or horizontal orientation can cause problems in terms of installation location. Summary of the Invention

[0004] The object of the present invention is to provide a fluidized bed dryer and a method for drying wet materials in a fluidized bed dryer, which at least alleviate the problems of the prior art.

[0005] The object of the present invention is achieved by a fluidized bed dryer and a method for drying wet materials in the fluidized bed dryer, characterized by the features set forth in the independent claims. Preferred embodiments of the invention are disclosed in the dependent claims.

[0006] This invention is based on the concept of drying wet materials, which can be varied according to the process and is more efficient and faster than conventional fluidized bed dryers. The materials may include fibrous materials, bio-based fibers, mineral materials, sludge, biomass, or any other materials that can be dried in a fluidized bed dryer.

[0007] According to the present invention, a fluidized bed dryer for drying wet materials using dry air includes, at its lower part: a wet material supply connector disposed on the side wall of the fluidized bed dryer, through which wet material is fed into the fluidized bed dryer; and a dry air supply connector, through which dry air is fed into the fluidized bed dryer. The fluidized bed dryer also includes, at its upper part, a discharge outlet through which a mixture of dried material and dry air is discharged from the fluidized bed dryer. The dry air supply connector and the discharge outlet determine the flow direction within the fluidized bed dryer from the dry air supply connector to the discharge outlet. The fluidized bed dryer also includes two or more drying zones arranged vertically between the dry air supply connection and the outlet inside the fluidized bed dryer. These consecutive drying zones are separated from each other by perforated partition walls to form a flow connection between the consecutive drying zones. An additional dry air supply connection is connected to each drying zone and is arranged to feed additional dry air to the drying zone.

[0008] In other words, the fluidized bed dryer according to the invention is a vertical fluidized bed dryer having a top end and a bottom end, such that the fluidized bed dryer extends between the top and bottom ends. The fluidized bed dryer receives wet material at its lower part via a connector located on the side wall of the fluidized bed dryer. A drying air supply connector is also located at the lower part of the fluidized bed dryer, through which drying air is supplied to the fluidized bed dryer. The drying air supply connector may be located on the side wall or bottom end of the fluidized bed dryer, or on an inclined wall extending from the side wall to the bottom end, if such an inclined wall exists. For clarity, the bottom end of the fluidized bed dryer is an end of the fluidized bed dryer that is opposite the top end of the vertically extending fluidized bed dryer, i.e., the other end of the fluidized bed dryer, while the upper part of the fluidized bed dryer is a larger entity than just the top end, i.e., the end of the fluidized bed dryer, and includes, to a maximum extent, the portion of the fluidized bed dryer extending upward from the middle of the fluidized bed dryer. Similarly, the lower part of the fluidized bed dryer is, to a maximum extent, the portion of the fluidized bed dryer that extends downwards from the middle. The wet material is arranged to float inside the fluidized bed dryer by means of drying air supplied from the lower part of the fluidized bed dryer. The wet material floats in the fluidized bed dryer by means of the drying air supplied to the fluidized bed dryer and mechanical agitation when necessary.

[0009] Dry air is discharged from the fluidized bed dryer through an outlet located at the top of the dryer, and in a preferred embodiment, at the very top. The dried material is removed from the dryer along with the drying air through the outlet. The drying air supplied to the dryer from the bottom is warm and dry, designed to dry the wet material, while the drying air discharged from the top is moist, having already incorporated moisture from the wet material after drying.

[0010] The flow direction of dry air in a fluidized bed dryer is from bottom to top. The dry air supply connection and the outlet determine the flow direction from the dry air supply connection to the outlet in the fluidized bed dryer. This means that the operating direction of the fluidized bed dryer is from bottom to top.

[0011] A fluidized bed dryer comprises two or more drying zones, meaning there are at least two drying zones. These drying zones are separated from each other by partition walls and are stacked vertically on top of each other. This means, for example, in the case of only two drying zones, the fluidized bed dryer comprises two drying zones separated from each other by partition walls and together forming the drying zone of the fluidized bed dryer. The fluidized bed dryer may also include a floating chamber in its lower part, into which wet material and drying air are supplied and the wet material begins to float. This floating chamber can be a separate chamber, meaning it is separated from the lowermost drying zone by a partition wall, or it can be part of the lowermost drying zone. The same applies to cases with more than two drying zones. To allow drying air and material to flow from the lower part of the fluidized bed dryer to the upper part, the partition walls between successive drying zones include openings through which drying air and material flow from the previous drying zone to the successive drying zone, i.e., from the lower drying zone to the successive upper drying zone.

[0012] For each drying zone, the fluidized bed dryer has an additional dry air supply connection that supplies dry and warm additional dry air to that drying zone. The dry and warm additional dry air promotes the drying of the wet material because the main dry air supplied through the dry air connection at the bottom of the fluidized bed dryer loses its energy, i.e., heat, within the fluidized bed dryer.

[0013] According to the present invention, a flow pipe is provided in the opening in the partition wall separating the continuous drying zones, the flow pipe forming a flow channel through which the mixture of material and drying air is arranged to flow from one drying zone to another continuous drying zone.

[0014] In other words, the flow tube is arranged to connect with the partition wall separating the continuous drying zones, such that the flow channel extending through the flow tube is in flow connection with the opening. Thus, the opening is provided with a flow tube extending toward the drying zone. This flow tube is connected to the partition wall.

[0015] According to the invention, the flow tube is arranged to extend in the flow direction from the opening to the previous drying zone. This means that the flow tube is arranged to extend from the opening to the downstream side of the opening. It also means that, in the drying zone, the opening is located in the bottom wall of the drying zone, which is a partition separating the drying zone from the previous consecutive drying zone, and this bottom wall has the opening through which the mixture of material and drying air comes from the previous drying zone, and in the same drying zone, the flow tube is arranged to extend from the top wall of the drying zone toward the drying zone, wherein the top wall is a partition separating the drying zone from the next consecutive drying zone. An exception to this is the first drying zone, in which drying air and material are supplied through separate connections, and since there is no previous consecutive drying zone, there is no bottom wall.

[0016] According to the invention, the flow tube is adjustable in length to regulate the flow of the mixture of material and dry air through the flow tube from one drying zone to another; or alternatively, the flow tube is adjustable in diameter to regulate the flow of the mixture of material and dry air through the flow tube from one drying zone to another; or alternatively, the flow tube is adjustable in both length and diameter to regulate the flow of the mixture of material and dry air through the flow tube from one drying zone to another.

[0017] According to the invention, the partition wall separating the continuous drying zones comprises a truncated cone that opens upward in the flow direction, guiding at least a portion of the mixture of material and drying air toward the sidewall of the fluidized bed dryer.

[0018] In other words, the partition separating the continuous drying zones comprises a truncated cone, which may be only part of the partition or the partition may be entirely in the form of a truncated cone. The truncated cone comprises two circular bases and one side, which means that when the truncated cone forms the partition separating the continuous drying zones, the side forms the partition separating the continuous drying zones, and the opening of the partition is the smaller of the two circular bases.

[0019] According to the present invention, an additional dry air supply connector is arranged in the side wall of the fluidized bed dryer to supply additional air tangentially to the drying zone.

[0020] This means that the additional dry air supply connector is arranged so that the additional dry air flow enters the drying zone tangentially. The additional dry air connector is located on the side wall of the fluidized bed dryer, such that the connector is arranged tangentially relative to the drying zone, and the additional dry air entering the drying zone will flow along the inner surface of the fluidized bed dryer, that is, along the side wall of the drying zone, and provide vortices in the drying zone.

[0021] According to the present invention, an additional dry air supply connector is arranged at the upper part of the drying zone.

[0022] In other words, the additional dry air supply connector is arranged above the center of the drying zone. This means that when the drying zone is horizontally divided into two halves with equal dimensions on both sides, the additional dry air supply connector is arranged on the sidewall of the upper half of the drying zone. The additional dry air supply connector is preferably arranged at the same horizontal height as the flow pipe in the vertical direction, meaning that the additional dry air supply connector supplies air, causing it to flow along the inner surface of the sidewall facing the flow pipe, into the space between the inner surface of the sidewall and the flow pipe.

[0023] According to the present invention, each additional dry air supply connector is adapted to regulate the amount of additional dry air supplied to the drying zone.

[0024] This means that the additional dry air supply connection is adjustable, for example, by controlling a damper, allowing for regulation of the additional airflow supplied through the connection. The additional dry air supply connection can be adjusted online.

[0025] According to the invention, each drying zone further includes a flow baffle arranged in the drying zone at a vertical distance from the opening leading to the next drying zone in the flow direction.

[0026] In other words, the drying zone includes flow baffles that guide the flow of the material-drying air mixture from the previous continuous drying zone toward the sidewall of the fluidized bed dryer and prevent the flow from directly entering the flow tube leading to the next continuous drying zone. This increases the time the material to be dried spends in the drying zone. The dimensions of the flow baffles are preferably larger than the inlet size of the flow tube. The flow tube includes an inlet and an outlet, as well as a flow channel extending between the inlet and outlet. The inlet is located in the drying zone, and the outlet connects to an opening in the partition wall. The flow baffles can be arranged in the drying zone at a vertical distance, for example, 10-50 cm, from the inlet of the flow tube.

[0027] According to the invention, the flow baffle is a flat plate baffle extending transversely to the vertical direction in the drying zone. Alternatively, the flow baffle is a conical baffle having a apex facing an opening leading to the next drying zone in the flow direction. Alternatively, the flow baffle is a hemispherical baffle having a apex facing away from the opening leading to the next drying zone in the flow direction.

[0028] In other words, the flow baffle is shaped to guide the mixture of material and drying air flowing from the previous drying zone to the current drying zone so that the mixture does not flow directly forward to the next subsequent drying zone, but instead flows within the drying zone together with additional drying air from the additional drying air connection, so that the material is dried along with the drying air. The shape of the flow baffle arranged in the drying zone can vary based on the material and / or its moisture content.

[0029] The method for drying wet material in a fluidized bed dryer according to the present invention comprises the following steps: a) supplying wet material and drying air to the fluidized bed dryer through a separate connector at the bottom of the fluidized bed dryer, and drying the wet material with the drying air; b) further drying the wet material by supplying additional drying air to a drying zone arranged at the bottom of the fluidized bed dryer above the connector for supplying wet material and drying air, thereby adding dry and warm additional drying air to the drying zone and generating a mixture of material and drying air; c) guiding the mixture of material and drying air in the vertical direction of the fluidized bed dryer to a subsequent drying zone through openings provided in the partition walls separating continuous drying zones in the fluidized bed dryer; and d) discharging the mixture of dried material and drying air from the fluidized bed dryer through a discharge outlet provided at the top of the fluidized bed dryer.

[0030] In other words, in this method, warm and dry air is fed to the lower part of the fluidized bed dryer in such a way that the wet material fed to the lower part of the fluidized bed dryer begins to float with the help of the dry air and is dried by the warm and dry air. As the material dries, moisture is transferred into the dry air, and the dry air loses heat. Therefore, there is a drying zone to which additional dry air is supplied for further drying of the wet material. The additional dry air is warm and dry, and it mixes with the dry air from the lower part that has already lost heat during the drying process, so the material can be further dried in the drying zone by means of the additional dry air.

[0031] Finally, the mixture of material and dry air is guided vertically through the fluidized bed dryer to the next consecutive drying zone. These consecutive drying zones are flow-connected by openings in the partition walls separating them. The drying process continues in this consecutive drying zone in a manner similar to the previous drying zone, and finally, the dried material and the now-moistened dry air are discharged from the fluidized bed dryer through the outlet.

[0032] According to the invention, the method further includes the step of supplying additional dry air to a subsequent drying zone.

[0033] In other words, additional drying air is supplied to each successive drying zone to increase the amount of warm and dry air, so that the material is dried more effectively in that drying zone before moving to the next successive drying zone or finally leaving the fluidized bed dryer.

[0034] According to the invention, step c) further includes guiding the mixture of material and dry air into a flow tube having a flow channel extending from the opening to the current drying zone and guiding the mixture through the flow channel to a subsequent drying zone.

[0035] In other words, in this method, the mixture of material and dry air is guided through a flow tube to the next consecutive drying zone. The length and / or diameter of the flow tube can be varied, allowing the flow rate of the mixture from one drying zone to another to be adjusted according to, for example, the material being dried.

[0036] According to the present invention, the method further includes the step of controlling the mixture of material and drying air in the drying zone by using a flow baffle placed in the drying zone to prevent the mixture of material and drying air from flowing directly to the opening leading to the continuous drying zone, the flow baffle being arranged at a position in the flow direction at a vertical distance from the opening leading to the next drying zone.

[0037] According to the invention, the method further includes supplying additional drying air by introducing additional drying air tangentially into the drying zone to create vortices in the drying zone for the mixture of wet material and drying air.

[0038] By tangentially directing additional drying air into the drying zone, the mixture of material and drying air rotates within the drying zone, thus promoting the drying of the material. In other words, the tangentially directed additional drying air introduces rotational motion into the floating material within the drying zone.

[0039] One advantage of the present invention is that wet materials are dried more efficiently in the fluidized bed dryer according to the invention, wherein the time spent in the fluidized bed dryer is reduced because each drying zone dries the material more quickly by means of an effective supply of fresh, warm and dry additional air, and the movement of the material enhances the drying process. Attached Figure Description

[0040] The invention will be described in detail with reference to the accompanying drawings and specific embodiments, in which: Figure 1 A fluidized bed dryer according to the present invention is shown; Figure 2 Another fluidized bed dryer according to the invention is shown; Figure 3 Another fluidized bed dryer according to the invention is shown; and Figure 4 Another fluidized bed dryer according to the invention is shown as part of the process. Detailed Implementation

[0041] Figure 1 A fluidized bed dryer 1 according to the invention is shown, wherein the fluidized bed dryer 1 includes a top end 20 and a bottom end 30, such that the fluidized bed dryer 1 extends between the top end 20 and the bottom end 30. The fluidized bed dryer 1 also includes a sidewall 14 surrounding a drying chamber inside the fluidized bed dryer 1. According to the invention, the fluidized bed dryer 1 includes two or more consecutive drying zones 2. The drying zones 2 form the drying chamber, and therefore the drying chamber is not referred to in the figures because the drying zones 2 form the drying chamber. Figure 1 The embodiment of the fluidized bed dryer 1 according to the invention shown includes two consecutive drying zones 2, which are stacked vertically on top of each other. Drying air is supplied to the fluidized bed dryer 1 from its lower portion, and in this embodiment, it is supplied via a drying air supply connector 11 disposed on the side wall 14 of the fluidized bed dryer 1. The drying air is supplied to the lower portion of the fluidized bed dryer 1, and preferably near the bottom end 30 of the fluidized bed dryer 1, such that when wet material is supplied via the wet material supply connector 10 disposed on the side wall 14 of the fluidized bed dryer 1 at its lower portion, the drying air causes the wet material to float within the fluidized bed dryer 1. Thus, the drying air is preferably supplied to the fluidized bed dryer 1 from below the supply of wet material. The lowermost drying zone 2 may be separated from the portion of the fluidized bed dryer 1 that supplies wet material and drying air, but is not necessarily so; this portion thus forms a floating chamber, which is the lowermost part of the fluidized bed dryer and the place where the wet material begins to float. For clarity, the floating chamber is not shown in these figures because the invention relates to a drying zone.

[0042] Dry air supplied via dry air supply connector 11 and wet material supplied via wet material supply connector 10 form a mixture of material and dry air. This mixture moves in a first drying zone 2 located at the lower part of the fluidized bed dryer 1, where the warm, dry air supplied via dry air supply connector 11 dries the wet material while simultaneously losing its heat. Warm, dry additional dry air is supplied to the upper part of the same drying zone 2 via additional dry air supply connector 13. This additional dry air is supplied in such a tangential additional airflow into the drying zone 2 that it mixes with the mixture of material and dry air from the lower part of the drying zone 2. The tangential additional airflow causes the mixture to vortex in the drying zone 2, and the material in the mixture is further dried with fresh, warm, dry additional air. The drying zone 2 is provided with flow baffles 5, which prevent the mixture of material and dry air from escaping directly from the drying zone 2 to the next consecutive drying zone 2, but instead guide the mixture towards the sidewall 14, thus keeping the mixture in the current drying zone 2 for a longer period. Figure 1 In the example shown, the flow baffle 5 in the lower drying zone 2 is a flat baffle, while the flow baffle 5 in the upper drying zone 2 is a conical baffle. However, these are exemplary figures, and in normal circumstances, the flow baffle 5 is typically the same in each drying zone 2.

[0043] Finally, the mixture of material and dry air flows from the current drying zone 2 to the next consecutive drying zone 2 through openings 4 arranged in the partition walls 3 separating the consecutive drying zones 2. Figure 1 In the example shown, the partition wall 3 is provided with a flow pipe 6, which forms a flow channel 7 inside the flow pipe 6. The flow channel 7 and the opening 4 are in flow communication with each other, such that the mixture flowing through the flow channel 7 also flows through the opening 4 to the next consecutive drying zone 2. The flow pipe 6 is connected to the partition wall 3 such that the opening 4 and the flow channel 7 are preferably concentric. The flow pipe 6 can be connected to the partition wall 3 such that the flow pipe 6 is disposed within the opening 4 and connected to the circumference of the opening 4. Alternatively, the flow pipe 6 can be connected to the partition wall 3 on the side facing the lower drying zone 2. The flow pipe 6 extends from the partition wall 3 in the direction of the lower drying zone 2.

[0044] The mixture of material and drying air floats in the next consecutive drying zone 2 in a similar manner to the previous drying zone 2, and additional drying air is similarly supplied to the drying zone 2. The additional drying air connector 13 is preferably arranged in the side wall 14 of the fluidized bed dryer 1 at a height such that the additional air arriving through the connector 13 is fed above half the vertical direction in each drying zone 2, and preferably fed into the area where the flow tube 6 extends. Thus, in other words, the additional drying air is preferably supplied between the side wall 14 and the flow tube 6. The supply of additional drying air can be controlled online, for example, by a control damper 40 that can adjust the amount of additional drying air supplied to the drying zone 2, or otherwise.

[0045] The mixture of dried material and dry air is finally discharged through the discharge outlet 12 at the top 20 of the fluidized bed dryer 1. Figure 1 The example shown includes only two drying zones 2, but the invention is not limited to only two drying zones 2. Depending on the process using the fluidized bed dryer 1, there may be two or more drying zones 2.

[0046] Figure 2 Another fluidized bed dryer 1 according to the invention is shown, wherein the features of the fluidized bed dryer 1 are the same as those of the fluidized bed dryer 1. Figure 1 The features in the illustrated embodiments are the same, and therefore will not be repeated here. However, there are differences. Figure 1 Two features distinguish the illustrated implementation. The first difference is that the drying air supply connector 11, which supplies the main drying air to the fluidized bed dryer 1, is located at the bottom 30 of the fluidized bed dryer 1. The second difference is the flow baffle 5, in... Figure 2 In the example shown, the flow baffle 5 is a flat baffle in the lower drying zone 2, while in the upper drying zone 2, the flow baffle 5 is a hemispherical baffle having a apex facing away from the opening leading to the next drying zone in the flow direction. However, these are exemplary figures, and in normal circumstances, the flow baffle 5 is typically the same in each drying zone 2.

[0047] Figure 3Another fluidized bed dryer 1 according to the invention is shown, comprising three drying zones 2 stacked vertically on top of each other. A dry air supply connection 11 is provided at the bottom 30 of the fluidized bed dryer 1, and a wet material supply connection 10 is provided at the lower part of the fluidized bed dryer 1 at the side wall 14 of the fluidized bed dryer 1. An additional dry air supply connection 13 is arranged similarly to the example shown in the previous figures. The partition walls 3 separating the drying zones 2 from each other are in the form of truncated cones, which open upwards in the flow direction of the mixture of material and dry air. An opening 4 is provided with a flow tube 6 extending downwards from the truncated cone partition wall 3 toward the previous drying zone 2. The truncated cone partition wall 3 guides at least a portion of the mixture of material and dry air flowing along the flow channel 7 of the flow tube 6 toward the side wall 14 of the fluidized bed dryer 1. In other words, the mixture of material and dry air first moves in the lower part of drying zone 2, and the flow baffle 5 guides the mixture toward the side wall 14, where additional dry air is added to mix with the mixture and further dry the material. From there, the mixture flows to the flow tube 6 and through the flow channel 7 and the opening 4 to reach the next consecutive drying zone 2. The truncated conical partition 3 guides the mixture flow toward the side wall 14, and the drying of the material continues, with additional dry air mixed with the mixture. In the last drying zone 2 at the top of the fluidized bed dryer 1, the mixture is discharged from the fluidized bed dryer through the discharge connector 12 at the top 20 of the fluidized bed dryer 1.

[0048] Figure 4 Another fluidized bed dryer 1 according to the invention is shown as part of the process. Figure 4 The embodiment of the fluidized bed dryer 1 shown includes, in its lower part, a wet material supply connector 10 disposed at the side wall 14 of the fluidized bed dryer 1, through which wet material is fed into the fluidized bed dryer 1; and a dry air supply connector 11 through which dry air is fed into the fluidized bed dryer 1. In this embodiment of the invention, the dry air supply connector 11 is arranged at the bottom end 30 of the fluidized bed dryer 1. The fluidized bed dryer 1 includes an outlet 12 in its upper part, specifically at its top end 20, through which a mixture of dried material and dry air is discharged from the fluidized bed dryer 1. The dry air supply connector 11 and the outlet 12 determine the flow direction from the dry air supply connector 11 to the outlet 12 in the fluidized bed dryer 1, meaning the flow direction is from bottom to top. Figure 4In this embodiment, the fluidized bed dryer 1 includes two drying zones 2 arranged vertically and continuously between a drying air supply connection 11 and a discharge outlet 12 within the fluidized bed dryer 1. The continuous drying zones 2 are separated from each other by a partition wall 3 with openings 4 to form a flow connection between them. The fluidized bed dryer 1 also includes an additional drying air supply connection 13 connected to each drying zone 2, arranged to feed additional drying air to the drying zone 2. The mixture of material and drying air moves through the fluidized bed dryer 1 from one drying zone 2 to another, and when the material is dry, the mixture is finally discharged through the discharge outlet 12 to the next process stage.

[0049] The invention has been described above with reference to the examples shown in the accompanying drawings. However, the invention is by no means limited to the above examples, but can be varied within the scope of the claims.

Claims

1. A fluidized bed dryer (1) for drying wet materials using dry air, the fluidized bed dryer (1) comprising, at its lower part: A wet material supply connector (10) is disposed on the side wall (14) of the fluidized bed dryer (1) to feed the wet material to the fluidized bed dryer (1); and a dry air supply connector (11) is provided to feed the dry air to the fluidized bed dryer (1). The fluidized bed dryer (1) includes a discharge outlet (12) at its upper part, through which a mixture of dried material and drying air is discharged from the fluidized bed dryer (1). The dry air supply connector (11) and the outlet (12) determine the flow direction from the dry air supply connector (11) to the outlet (12) in the fluidized bed dryer (1), characterized in that the fluidized bed dryer (1) further includes: Two or more drying zones (2) are arranged vertically and continuously within the fluidized bed dryer (1) between the drying air supply connection (11) and the outlet (12). The continuous drying zones (2) are separated from each other by partition walls (3) with openings (4) to form a flow connection between the continuous drying zones (2). An additional dry air supply connector (13) is connected to each drying zone (2), the additional dry air supply connector (13) being arranged to feed additional dry air to the drying zone (2).

2. The fluidized bed dryer (1) according to claim 1, characterized in that, A flow pipe (6) is provided in the opening (4) in the partition wall (3) that separates the continuous drying zones (2), the flow pipe (6) forming a flow channel (7), and the mixture of material and drying air is arranged to flow from one drying zone (2) to another continuous drying zone (2) through the flow channel (7).

3. The fluidized bed dryer (1) according to claim 2, characterized in that, The flow tube (6) is arranged to extend from the opening (4) to the previous drying zone (2) in the flow direction.

4. The fluidized bed dryer (1) according to claim 2 or 3, characterized in that, The flow tube (6) is adjustable in length; or The flow tube (6) is adjustable in diameter; or The flow tube (6) is adjustable in both length and diameter. The flow of the mixture of the material and the dry air through the flow pipe (6) is adjusted to flow from one drying zone (2) to another drying zone (2).

5. The fluidized bed dryer (1) according to any one of the preceding claims, characterized in that, The partition wall (3) separating the continuous drying zones (2) includes a truncated cone that opens upward in the flow direction, guiding at least a portion of the mixture of material and drying air toward the sidewall (14) of the fluidized bed dryer (1).

6. The fluidized bed dryer (1) according to any one of the preceding claims, characterized in that, The additional dry air supply connector (13) is arranged in the side wall (14) of the fluidized bed dryer (1) to supply additional air tangentially to the drying zone (2).

7. The fluidized bed dryer (1) according to claim 6, characterized in that, The additional dry air supply connector (13) is located at the upper part of the drying zone (2).

8. The fluidized bed dryer (1) according to any one of the preceding claims, characterized in that, Each of the additional dry air supply connectors (13) is adapted to adjust the amount of additional dry air supplied to the drying zone (2).

9. The fluidized bed dryer (1) according to any one of the preceding claims, characterized in that, Each drying zone (2) also includes a flow baffle (5) which is arranged in the drying zone (2) at a position in the flow direction that is a vertical distance away from the opening (4) leading to the next drying zone (2).

10. The fluidized bed dryer (1) according to claim 9, characterized in that, The flow baffle (5) is: A flat baffle, the flat baffle extending transversely to the vertical direction in the drying zone (2); or A conical baffle, the apex of which faces the opening (4) leading to the next drying zone (2) in the flow direction. or A hemispherical baffle, the apex of which is opposite to the opening (4) leading to the next drying zone (2) in the flow direction.

11. A method for drying wet materials in a fluidized bed dryer (1), characterized in that, The method includes the following steps: a) Wet material and drying air are supplied to the fluidized bed dryer (1) through separate connectors (10, 11) at the bottom of the fluidized bed dryer (1), and the wet material is dried with the drying air. b) By supplying additional dry air to the drying zone (2) located below the fluidized bed dryer (1) and above the connectors (10, 11) that supply wet material and dry air, dry and warm additional dry air is added to the drying zone (2) and a mixture of material and dry air is generated, thereby further drying the wet material. c) The mixture of material and drying air is guided vertically into the subsequent drying zone (2) of the fluidized bed dryer (1) through openings (4) in the partition walls (3) that separate the continuous drying zones (2) in the fluidized bed dryer (1), and d) The mixture of dried material and dry air is discharged from the fluidized bed dryer (1) through the discharge outlet (12) located at the top of the fluidized bed dryer (1).

12. The method according to claim 11, characterized in that, The method further includes the following steps: Additional dry air is supplied to the subsequent drying zone (2).

13. The method according to claim 11 or 12, characterized in that, Step c) also includes: The mixture of the material and dry air is guided to a flow tube (6) having a flow channel (7) that extends from the opening (4) to the current drying zone (2) and guides the mixture through the flow channel (7) to the subsequent drying zone (2).

14. The method according to any one of claims 11 to 13, characterized in that, The method further includes the following steps: The mixture of material and dry air in the drying zone (2) is controlled by using a flow baffle (5) placed in the drying zone (2) to prevent the mixture of material and dry air from flowing directly into the opening (4) leading into the continuous drying zone (2). The flow baffle (5) is arranged at a vertical distance from the opening (4) leading to the next drying zone (2) in the flow direction.

15. The method according to any one of claims 11 to 14, characterized in that, The method further includes: The additional drying air is supplied by introducing additional drying air tangentially into the drying zone (2) to create a vortex in the drying zone (2) for the mixture of wet material and dry air.

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