Fluidized bed granulation dryer

Abstract

The utility model relates to the technical field of fluidized bed granulation, in particular to a fluidized bed granulation dryer, which comprises a bed body, a spray gun and a spray gun driving mechanism, an air inlet chamber, a fluidization chamber and a settling chamber are sequentially arranged in the bed body from bottom to top, and an air distribution plate is arranged between the air inlet chamber and the fluidization chamber. In the granulating and drying process, the spray gun is driven by the spray gun driving mechanism to move, so that an atomized liquid drop receiving area which continuously and periodically moves circularly is formed in a top material layer area of the fluidized bed layer. The material is periodically and intermittently subjected to liquid in the granulation area covered by the atomization area of each spray gun, so that the contradiction that the drying rate of the biomass type material difficult to dry is lower than the granulation rate can be effectively solved, and the problem that the material in the granulation area is too high in humidity and too long in viscidity duration time to form coarse particles or cakes is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of fluidized bed granulation drying, in particular to a fluidized bed granulation dryer. Background Art

[0002] Fluidized bed spray granulation drying technology is a technology that directly sprays, granulates, and dries liquid materials in a fluidized bed to obtain granular products. Its working principle is that in a fluidized bed, liquid materials are atomized into tiny droplets through one or more spray guns (atomizers) and sprayed onto the surfaces of a large number of particles in a fluidized granular material bed layer to complete the granulation and drying process. In the area where the droplet atomization zone intersects with the fluidized bed layer, a so-called granulation zone is formed, and the granulation and drying processes are carried out simultaneously. There are two main granulation mechanisms in the granulation zone. One is that droplets adhere multiple particles together in the form of "liquid bridges", so as to grow in the way of continuous agglomeration between particles; the other is that droplets adhere to the surface of a single particle to form a local or continuous liquid film, so as to grow in the way of continuous coating on the particle surface. The high-temperature gas fluidizes the particles and also provides all or part of the heat to evaporate and remove the water in the liquid bridge or liquid film. The liquid film or liquid bridge continuously decreases during the drying process and finally loses its bonding characteristics, and the corresponding granulation process continuously weakens and finally stops, while the solid components in the liquid film or liquid bridge are finally solidified into a part of the particles. The above granulation and drying processes achieved through particle agglomeration or coating are continuously carried out in the fluidized bed, and finally granular products with a certain size and shape are obtained. Currently, the common continuous fluidized bed granulation dryers in industrial production are divided into various forms such as side spray type, top-down spray type, or bottom-up spray type according to the positions of the spray guns.

[0003] The specific implementation form of the top-down spray type fluidized bed granulation dryer can refer to the fluidized bed disclosed in CN102744010B. The bed body of the fluidized bed is composed of a shell. Inside the shell, an air distribution chamber area, an air distribution screen plate, a fluidization chamber area, and a separation chamber area are successively arranged from bottom to top. The top of the bed body is provided with a nozzle and an air outlet, etc. Its spray gun is arranged above the fluidized bed and is higher than the fluidized bed layer. After the liquid is atomized, it is sprayed downward from top to the upper surface of the bed layer and penetrates a certain thickness of the bed layer, so as to form a granulation zone in the local bed layer where the spray gun atomization zone contacts the fluidized material layer and complete the granulation process. The area outside the granulation zone is the drying zone, and the materials are further dried in the drying zone and finally recycled to the granulation zone to enter the next granulation process. In order to improve the heat supply capacity, an internal heat exchanger can be set in the drying zone. According to the different production capacities of the device and the atomization capabilities of the spray guns, single-rod or multi-rod spray guns can be set, and a certain distance is arranged between the multi-rod spray guns to avoid situations such as excessive humidity in the granulation zone and untimely drying, resulting in the growth of particles into coarse particles or even caking.

[0004] For many biomass materials that are difficult to dry, especially materials such as fermentation broth and waste liquid after extraction in the fermentation industry, they contain various organic and inorganic components. The drying rate of these materials is slow and they have strong viscosity (or thermal viscosity), and these characteristics all have an adverse impact on the granulation drying process. A significant feature of such materials during the drying process is that the rate of moisture migration from the inside of the droplet or wet material to the outer surface is much lower than the rate of moisture evaporation from the outer surface to the surrounding gas environment. Therefore, its drying process is mainly controlled by the internal moisture migration process and requires a long time to complete drying, belonging to typical difficult-to-dry materials. During the granulation process, due to the slow drying rate of the material, the material will remain in a strong wet and sticky state for a long time, correspondingly resulting in the continuous progress of the granulation process. When the granulation time is too long, a large number of particles will grow beyond the process requirements. When applying the existing top-bottom spray fluidized bed granulation dryer to such difficult-to-dry materials, since the atomization zone formed by the spray gun remains fixed, when the continuous migration and renewal of the material in the granulation zone are insufficient, it will cause the particles in the granulation zone to continuously receive droplet spraying, and the moisture will continuously accumulate and increase, resulting in a large number of oversized particles or agglomerates beyond the design range, causing fluidization deterioration or even dead bed in the local area, forcing the production to stop. For some biomass thermally viscous materials, such as sugars or materials containing sugar components, with the increase of temperature, the viscosity of their liquid, wet material and even the dried particles themselves will also increase correspondingly. During the drying process, inevitably accompanied by the increase of the material temperature, the superposition of these two characteristics of such difficult-to-dry materials is more likely to lead to too fast particle growth rate and the problem of generating coarse particles or agglomerates.

[0005] To solve this problem, the methods adopted by the prior art are to reduce the liquid spraying amount of a single-rod spray gun and arrange more spray guns at the same time to meet the production capacity requirements; or take measures such as increasing the fluidization speed and designing the flow field of the bed layer to strengthen the renewal of particles; or reducing the inlet air temperature and at the same time reducing the liquid spraying amount of a single gun to maintain the granulation stability in a way of reducing the production capacity. These methods bring problems such as increased equipment investment and higher production costs. Utility Model Content

[0006] The purpose of the present utility model is to provide a fluidized bed granulation dryer, which drives the spray gun to rotate and / or swing through a spray gun driving mechanism, so as to continuously and periodically move the liquid droplet receiving area of the atomized liquid, and realize the periodic intermittent liquid receiving of the material in the granulation area covered by the atomization area of each spray gun, which can effectively solve the contradiction that the drying rate of difficult-to-dry biomass materials is lower than the granulation rate, thereby preventing the problem of forming coarse particles or agglomerates due to too high humidity of the material in the granulation area and too long duration of material viscosity.

[0007] An embodiment of the present utility model provides a fluidized bed granulation dryer, which includes a bed body, a spray gun and a spray gun driving mechanism. An air inlet chamber, a fluidization chamber and a sedimentation chamber are sequentially arranged in the bed body from bottom to top. A air distribution plate is arranged between the air inlet chamber and the fluidization chamber. The spray gun is installed at the top of the bed body through a ball hinge. The spray gun driving mechanism is used to drive the spray gun to rotate and / or swing. The spray gun driving mechanism includes a vertical driving device, a motor and a connecting rod. The vertical driving device is used to drive the motor to move vertically. The axis of the output shaft of the motor is in the vertical direction and passes through the center of the ball hinge. The two ends of the connecting rod are respectively pivotally connected to the output shaft of the motor and the spray gun.

[0008] During the granulation and drying process, the fluidized granular material in the fluidization chamber forms a fluidized bed layer. The upper surface of the fluidized bed layer is located in the fluidization chamber, and the nozzle of the spray gun is located above the upper surface of the fluidized bed layer. The liquid material is atomized into fine droplets by the spray gun and then falls downward to form an approximately conical atomization zone, covering the fluidized bed layer below it. The droplets fall onto the upper surface of the fluidized bed layer and penetrate into a certain thickness of the fluidized bed layer, thereby forming a granulation zone in the material layer in contact with the droplets and the surrounding areas with higher humidity. During the granulation and drying process, the spray gun is driven to move by the spray gun driving mechanism, so as to form a continuously and periodically circulating moving atomized droplet receiving area in the corresponding granulation zone. For a specific local area in the entire fluidized bed layer area covered by the atomized droplet receiving area, in each moving cycle of the atomized droplet receiving area, this local area can be divided into two stages: passing through the atomized droplet receiving area and not passing through the atomized droplet receiving area. When passing through the atomized droplet receiving area, the bed material in this local area receives the droplets and starts the granulation and drying process; when the atomized droplet receiving area leaves, the liquid receiving process of this local area bed layer terminates. During the period of stopping receiving liquid, since the hot air continuously enters this local area, and the wet material in this local area is violently mixed with the dry material in the surrounding area, the drying process continues, the humidity of the material continuously decreases, and the granulation process rapidly weakens. When the moisture content of the material in this local area drops to a certain extent, the viscosity of the material also weakens to the point where granulation is no longer possible. At this time, the granulation process ends, while the drying process is still ongoing until the dynamic equilibrium moisture of the material is reached and then stops. Under the same operating conditions, for materials with different granulation and drying characteristics, by adjusting parameters such as the size, moving cycle, trajectory, and moving speed of the granulation area covered by the atomized droplet receiving area, the entire granulation and drying process can be completed before the atomized droplet receiving area passes through this local area again, and then enter the next cycle.

[0009] With the above technical solutions, the technical solutions provided by the present utility model have at least the following advantages: (1) The present utility model drives the spray gun to rotate and / or swing through a spray gun driving mechanism, thereby continuously and periodically moving the liquid receiving area of the atomized droplets, and realizing the periodic intermittent liquid receiving of the material in the granulation area covered by the atomization area of each spray gun, which can effectively solve the contradiction that the drying rate of biomass materials that are difficult to dry, sticky or have strong thermal viscosity is less than the granulation rate, and enables the granulation-drying process to proceed stably, thereby preventing problems such as the formation of coarse particles or agglomerates due to excessive humidity of the material in the granulation area and too long duration of material viscosity. (2) It expands the area of the granulation area that can be covered by a single spray gun atomization, and can reach up to several times the coverage area of the existing fixed spray gun arrangement, thereby significantly reducing the number of spray guns arranged, and reducing the investment cost of the spray guns and their affiliated pipelines and control systems. (3) Compared with the multiple fixed granulation drying areas formed when the spray guns are fixedly arranged, the granulation drying area formed when the spray guns of the present utility model work can cover multiple fixed granulation drying areas and the void areas outside the granulation drying areas. Therefore, the method of moving the liquid receiving area of the atomized droplets of the present utility model can cover a larger range of the bed layer area than the atomization method of the fixed spray gun arrangement. For a specific material, when the fluidization wind speed and the inlet air temperature of the granulation bed are constant, the granulation drying intensity per unit area of the bed layer is a relatively stable value. Increasing the available bed layer area improves the equipment production capacity; when the equipment production capacity remains unchanged, increasing the available bed layer area is equivalent to reducing the granulation drying intensity per unit area, thereby increasing the operation stability of the equipment.

[0010] Further, a rotary joint is installed on the spray gun, and the material and the atomization medium enter the spray gun through the rotary joint.

[0011] Further, the rotary joint is coaxially and rotatably sleeved outside the spray gun; a material channel and an atomization medium channel are provided in the spray gun, and a material communication port and an atomization medium communication port communicating with the material channel and the atomization medium channel respectively are provided on the spray gun; a material ring cavity and an atomization medium ring cavity communicating with the material communication port and the atomization medium communication port respectively are provided in the rotary joint, and a material input port and an atomization medium input port communicating with the material ring cavity and the atomization medium ring cavity respectively are provided on the rotary joint.

[0012] Further, the included angle between the axis of the spray gun and the vertical direction is greater than 0° to avoid the "dead point" problem caused by the co-linearity of the connecting rod and the spray gun when the motor moves vertically.

[0013] Based on the same inventive concept, the present utility model further provides another fluidized bed granulating dryer, which includes a bed body, a spray gun and a spray gun driving mechanism. An air inlet chamber, a fluidization chamber and a sedimentation chamber are sequentially arranged in the bed body from bottom to top. A air distribution plate is arranged between the air inlet chamber and the fluidization chamber; the spray gun is hinged to the top of the bed body; the spray gun driving mechanism is used to drive the spray gun to swing. The spray gun driving mechanism includes a linear driving device, a sliding pin and a groove rod. The groove rod is fixedly connected to the spray gun. A linear sliding groove is arranged on the groove rod. The sliding pin is slidably matched with the linear sliding groove. The linear driving device is used to drive the sliding pin to move linearly. The moving direction of the sliding pin intersects with the extending direction of the linear sliding groove.

[0014] During the granulation and drying process, the spray gun is driven by the spray gun driving mechanism to swing periodically back and forth, so that the liquid receiving area of the atomized droplets moves continuously and periodically along a linear trajectory. In one cycle, the shape of the area covered by the liquid receiving area of the atomized droplets is an arc-angle rectangle. The arc angles at both ends thereof are the shape of the intersection line symmetric about the swing axis formed after the liquid receiving area of the atomized droplets intersects with the upper surface of the bed layer. Its width is equivalent to the width of the liquid receiving area of the atomized droplets formed by a single-rod fixed spray gun, and its length is equivalent to extending the liquid receiving area of the atomized droplets formed by a single-rod fixed spray gun along the length direction. Therefore, it not only covers the multiple liquid receiving areas of the atomized droplets formed by multiple fixed spray guns, but also fills the gaps between these liquid receiving areas of the atomized droplets, thereby achieving a larger coverage ratio of the bed layer area. At the same time, this moving liquid receiving area of the atomized droplets also brings better granulation and drying stability. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the fluidized bed granulating dryer in Embodiment 1, wherein, Figure 1 a is the front view, Figure 1 b is the top view.

[0016] Figure 2 For Figure 1 The partial enlarged view of part I in

[0017] Figure 3 It is a schematic structural diagram of the spray gun in Embodiment 1.

[0018] Figure 4 It is a schematic structural diagram of the ball hinge in Embodiment 1.

[0019] Figure 5 It is a schematic structural diagram of the fluidized bed granulating dryer in Embodiment 2, wherein, Figure 5 a is the front view, Figure 5 b is the top view.

[0020] Figure 6 It is a schematic structural diagram of the fluidized bed granulating dryer in Embodiment 3, wherein, Figure 6a is the front view, Figure 6 b is the side view, Figure 6 c is the top view.

[0021] Figure 7 It is a schematic diagram of the layout structure of the liquid receiving area for atomized droplets of an existing top-down spray fluidized bed granulation dryer.

[0022] Figure 8 It is a schematic diagram of the layout structure of the liquid receiving area for atomized droplets of the fluidized bed granulation dryer in Embodiment 4.

[0023] Figure 9 It is a schematic diagram of the structure of the fluidized bed granulation dryer in Embodiment 5, where, Figure 9 a is the front view, Figure 9 b is the side view, Figure 9 c is the top view.

[0024] Figure 10 is Figure 9 a partial enlarged view of part II in

[0025] Figure 11 It is a schematic diagram of the layout structure of the liquid receiving area for atomized droplets of another existing top-down spray fluidized bed granulation dryer.

[0026] Wherein: 1 - bed body, 2 - spray gun, 3 - air inlet chamber, 4 - straight section of fluidization chamber, 5 - settling chamber, 6 - air distribution plate, 7 - spherical hinge, 8 - motor, 9 - connecting rod, 10 - rotary joint, 11 - material channel, 12 - atomizing medium channel, 13 - material connection port, 14 - atomizing medium connection port, 15 - material ring cavity, 16 - atomizing medium ring cavity, 17 - material input port, 18 - atomizing medium input port, 19 - electric push rod, 20 - ball pin, 21 - sliding pin, 22 - groove rod, 23 - linear chute, 24 - enlarged section of fluidization chamber, 25 - air inlet, 26 - return port, 27 - discharge port, 28 - exhaust port, 29 - upper spherical bowl, 30 - lower spherical bowl, 31 - seal, 32 - linear module, 33 - bolt, 34 - long shaft, 35 - short shaft, 36 - liquid receiving area for atomized droplets, 37 - upper surface of fluidized bed layer, 38 - nozzle of spray gun, 39 - fixed liquid receiving area for atomized droplets, 40 - atomization area. Detailed implementation manners

[0027] The following embodiments further illustrate the present invention.

[0028] Embodiment 1

[0029] Cystine and cysteine hydrolysis solution is a biomass material that is difficult to dry and has strong thermal viscosity. In the prior art, a small intermittent circular fluidized bed granulation dryer is used for granulation and drying operations. A multi-rod fixed spray gun is set above the fluidized material layer, and the liquid material is atomized and sprayed downward onto the material layer for granulation operations. Since the drying speed of the liquid material is very slow, the wet particles exhibit strong thermal viscosity and are prone to caking and bed collapse phenomena. Only the method of spraying liquid with a small spray volume by a multi-rod spray gun can be used for low-load production, resulting in high energy consumption and poor economy.

[0030] This embodiment provides a fluidized bed granulation dryer. In this embodiment, the fluidized bed granulation dryer is a small intermittent top-down spray type fluidized bed granulation dryer for the granulation and drying of cystine and cysteine hydrolysis solution, including a bed body 1, a spray gun 2, and a spray gun driving mechanism.

[0031] As Figure 1 As shown in Fig. b, the horizontal cross-section of the bed body 1 is circular. Inside the bed body 1, an air inlet chamber 3, a fluidized chamber, and a settling chamber 5 are sequentially arranged from bottom to top, and a distributor plate 6 is arranged between the air inlet chamber 3 and the fluidized chamber. In this embodiment, the fluidized chamber includes a straight section 4 of the fluidized chamber and an enlarged section 24 of the fluidized chamber, and the enlarged section 24 of the fluidized chamber is located above the straight section 4 of the fluidized chamber. It should be noted that for those skilled in the art, the specific form of the fluidized chamber is not limited to the form shown in this embodiment. For example, the fluidized chamber can be composed only of the straight section 4 of the fluidized chamber, or only of the enlarged section 24 of the fluidized chamber. In addition, the fluidized chamber can also include the straight section 4 of the fluidized chamber and the enlarged section 24 of the fluidized chamber, and in this structure, the enlarged section 24 of the fluidized chamber can be located below the straight section 4 of the fluidized chamber. The fluidized particulate material located in the fluidized chamber constitutes a fluidized bed layer, and the upper surface 37 of the fluidized bed layer is located inside the fluidized chamber. An air inlet 25, a return port 26, an outlet 27, and an exhaust port 28 are provided on the bed body 1. The air inlet 25 is communicated with the air inlet chamber 3, the return port 26 and the outlet 27 are both communicated with the fluidized chamber, and the exhaust port 28 is communicated with the settling chamber 5.

[0032] The spray gun 2 is used to atomize the liquid material, and the spray gun 2 is installed at the top of the bed body 1 through a spherical hinge 7. Specifically, as Figure 4 shown, the spherical hinge in this embodiment includes a ball seat and a ball pin 20. The ball seat includes an upper ball bowl 29 and a lower ball bowl 30. The lower ball bowl 30 is fixedly installed on the bed body 1, and the upper ball bowl 29 is buckled on the lower ball bowl 30 and fixedly connected by bolts 33. The ball pin 20 is accommodated in the cavity formed by the upper ball bowl 29 and the lower ball bowl 30 and forms a spherical pair with the ball seat. The ball pin 20 is fixedly sleeved outside the spray gun 2. To ensure sealing, sealing members 31 are provided between the ball pin 20 and the ball seat and between the ball pin 20 and the spray gun 2.

[0033] The nozzle 38 of the spray gun is located above the upper surface 37 of the fluidized bed layer.

[0034] As Figure 2 shown, the spray gun driving mechanism includes a vertical driving device, a motor 8 and a connecting rod 9. The vertical driving device is used to drive the motor 8 to move vertically. In this embodiment, the vertical driving device is a linear module 32 in the vertical direction. The axis of the output shaft of the motor 8 is in the vertical direction and passes through the center of the spherical hinge 7. The two ends of the connecting rod 9 are respectively pivotally connected to the output shaft of the motor 8 and the spray gun 2. When the vertical driving device drives the motor 8 to move vertically, the angle of the spray gun 2 relative to the vertical direction can be adjusted, so as to adjust the spraying angle of the nozzle 38 of the spray gun. When the motor 8 rotates, the spray gun 2 can be driven to rotate through the connecting rod 9.

[0035] It should be noted that when the motor 8 moves vertically, it is necessary to ensure that the connecting rod 9 and the spray gun 2 are not collinear, that is, the angle between the axis of the spray gun 2 and the vertical direction needs to be greater than 0° to avoid the "dead point". In addition, the atomized droplets of the spray gun 2 should be prevented from spraying onto the inner wall of the bed body 1 to avoid scaling on the inner wall of the bed body 1. Therefore, there is a maximum value for the angle of the axis of the spray gun relative to the vertical direction, and the adjustment range of the spray gun axis angle during actual operation is between 0° and the maximum value.

[0036] As Figure 2 shown, a rotary joint 10 is installed on the spray gun 2, and the material and the atomizing medium enter the spray gun 2 through the rotary joint 10. Specifically, as Figure 3 shown, the rotary joint 10 is coaxially and rotatably sleeved outside the spray gun 2. The spray gun 2 is provided with a material channel 11 and an atomizing medium channel 12. The spray gun 2 is provided with a material communication port 13 and an atomizing medium communication port 14 that are respectively communicated with the material channel 11 and the atomizing medium channel 12. The rotary joint 10 is provided with a material ring cavity 15 and an atomizing medium ring cavity 16 that are respectively communicated with the material communication port 13 and the atomizing medium communication port 14. The rotary joint 10 is provided with a material input port 17 and an atomizing medium input port 18 that are respectively communicated with the material ring cavity 15 and the atomizing medium ring cavity 16. The material input port 17 and the atomizing medium input port 18 are respectively connected to the material source and the atomizing medium source through hoses. When the spray gun 2 rotates around the center of the spherical hinge 7, the rotary joint 10 rotates relative to the spray gun 2, and the cooperation with the hose can prevent the rotation or swing of the spray gun 2 from being interfered.

[0037] During the granulation and drying process, according to parameters such as the required product particle size, the size of the upper surface 37 of the fluidized bed layer, the liquid spraying speed of the spray gun 2, and the drying rate of the liquid material, first, the position of the motor 8 in the vertical direction is adjusted through the vertical driving device, so as to determine the angle of the spray gun 2 relative to the vertical direction; then, the spray gun 2 is driven by the motor 8 to rotate at a set rotational speed at a uniform angular velocity, so as to form a continuously and periodically circulating moving atomized liquid droplet receiving area 36 in the top layer area of the fluidized bed layer, and the atomized liquid droplet receiving area 36 continuously and periodically circulates along a circular trajectory.

[0038] As Figure 1 shown in b, within one period, the shape of the area covered by the atomized liquid droplet receiving area 36 is circular. In this embodiment, each liquid receiving point in the atomized liquid droplet receiving area 36 rotates around the center of the circle at the same angular velocity, the liquid receiving speeds of the particles located on the same circumference are the same, and the ratio of the liquid receiving time to the non-liquid receiving time is the same. Therefore, the liquid receiving uniformity is the best, and the granulation-drying stability is the best. Moreover, the symmetry of its granulation area is the best, the shape is simple, and the compatibility with the shape of the circular bed is good, making it easier to design the flow field of the fluidized bed layer to strengthen the renewal of the particles in the granulation area.

[0039] The technical principle of this embodiment is described as follows: The feed liquid is atomized into fine droplets by the spray gun 2 and then falls downward to form an approximately conical atomization zone 40, covering the fluidized bed layer below it. The droplets fall onto the upper surface of the fluidized bed layer and penetrate into a certain thickness of the fluidized bed layer, thereby forming a granulation zone in the material layer in contact with the droplets and the surrounding areas with higher humidity. During the granulation and drying process, the spray gun 2 is driven to move by the spray gun driving mechanism, and the atomization zone 40 makes a corresponding circular motion, thereby forming a continuous and periodically circulating moving atomized droplet receiving area 36 on the upper surface of the fluidized bed layer. For a specific local area of all the fluidized bed layer areas covered by the atomized droplet receiving area 36, in each moving cycle of the atomized droplet receiving area 36, this local area can be divided into two stages: passing through the atomized droplet receiving area and not passing through the atomized droplet receiving area. When passing through the atomized droplet receiving area 36, the bed material in this local area receives the droplets and starts the granulation and drying process; when the atomized droplet receiving area 36 leaves, the liquid receiving process of this local area bed layer terminates. During the period of stopping liquid receiving, since hot air continuously enters this local area, and the wet material in this local area is violently mixed with the dry material in the surrounding area, the drying process continues, the moisture content of the material continuously decreases, and the granulation process rapidly weakens. When the moisture content of the material in this local area drops to a certain extent, the viscosity of the material also weakens to a level insufficient for granulation. At this time, the granulation process ends while the drying process is still ongoing until the dynamic equilibrium moisture content of the material is reached and then it stops. Under the same inlet air temperature, fluidization velocity, and flow field conditions of the fluidized bed layer, for materials with different granulation and drying characteristics, by adjusting parameters such as the size, moving cycle, trajectory, and moving speed of the granulation area covered by the atomized droplet receiving area 36, the entire granulation and drying process can be completed in advance with an appropriate and controllable time interval before the atomized droplet receiving area 36 passes through this local area next time, and then enter the next cycle, thereby improving the granulation and drying efficiency. In this embodiment, by continuously and periodically moving the atomized droplet receiving area, the material is intermittently received in a periodic manner in the granulation area covered by the atomization zone 40 of each spray gun, which can effectively solve the contradiction that the drying rate of viscous materials such as biomass is less than the granulation rate, and enable the granulation-drying process to proceed stably, thereby preventing problems such as the formation of coarse particles or agglomerates due to excessive humidity of the material in the granulation area and too long duration of material viscosity.

[0040] Embodiment 2

[0041] Figure 5 Fig. 2 shows Embodiment 2 of the present invention.

[0042] The fluidized bed granulation dryer provided in this embodiment is the same as that in Embodiment 1. In this embodiment, during the granulation and drying process, within one cycle, the shape of the area covered by the liquid receiving area 36 of the atomized droplets is an annular shape. Since the inner area of the annular shape does not receive droplet spraying, the shape of each horizontal cross-section of the formed granulation area is also a corresponding annular shape. Due to the intense backmixing of the material particles constituting the fluidized bed layer occurring constantly in the vertical and horizontal directions, the boundary of the annular shape is dynamically changing. The dried particles in the outer area and the inner area of the annular shape cross the boundary of the annular shape and interact with the wet and sticky particles in the granulation area, accelerating the migration and renewal of the particles in the granulation area, rapidly reducing the wet and sticky state of the material in the granulation area and accelerating the drying speed, thereby alleviating the contradiction that the drying rate of the material in the granulation area is less than the granulation speed. The annular liquid receiving area of the atomized droplets has two boundaries, namely the outer circle and the inner circle. Therefore, compared with the circular liquid receiving area of the atomized droplets, the boundary area for heat and mass transfer around the granulation area formed by the annular liquid receiving area of the atomized droplets is larger, and the heat and mass transfer efficiency is higher, thus making the granulation-drying process more stable.

[0043] Embodiment 3

[0044] Figure 6 Embodiment 3 of the present invention is shown.

[0045] Molasses yeast tail liquor is the tail liquor after the waste liquor in the sugar industry undergoes fermentation and extraction of effective components. It contains various organic and inorganic components, with complex compositions, and belongs to a typical type of difficult-to-dry material. Its drying process is mainly controlled by the migration process of internal moisture, and the drying speed is slow. Therefore, during most of the drying process, it remains in a viscous liquid or semi-solid state, with strong viscosity and thermal viscosity. When using the existing top-down spray type fluidized bed granulation dryer to granulate and dry molasses yeast tail liquor, because the atomization and granulation area formed by the spray gun is fixed and unchanged, the particles in the granulation area continuously receive droplet spraying and increase moisture. However, the material characteristics result in the drying speed of the wet material being much less than the granulation speed, leading to the rapid appearance of a large number of oversized particles or agglomerates in the granulation area, and the occurrence of deteriorated fluidization or even dead bed in local areas, forcing the production to stop. Therefore, in actual production, only a very low single-gun liquid spraying speed can be controlled, and at the same time, the inlet air temperature is reduced to maintain the stability of the granulation-drying process.

[0046] This embodiment provides a fluidized bed granulation dryer, and the material for granulation is molasses yeast tail liquor. In this embodiment, the fluidized bed granulation dryer is a continuous top-down spray type fluidized bed granulation dryer, including a bed body 1, a spray gun 2, and a spray gun driving mechanism.

[0047] As Figure 6As shown, the horizontal cross-section of the bed body 1 is rectangular. Inside the bed body 1, an air inlet chamber 3, a fluidization chamber, and a settling chamber 5 are successively arranged from bottom to top. A distributor plate 6 is provided between the air inlet chamber 3 and the fluidization chamber. In this embodiment, the fluidization chamber includes a straight section 4 of the fluidization chamber and an enlarged section 24 of the fluidization chamber, and the enlarged section 24 of the fluidization chamber is located above the straight section 4 of the fluidization chamber. It should be noted that for those skilled in the art, the specific form of the fluidization chamber is not limited to the form shown in this embodiment. For example, the fluidization chamber can be composed only of the straight section 4 of the fluidization chamber, or only of the enlarged section 24 of the fluidization chamber. In addition, the fluidization chamber can also include the straight section 4 of the fluidization chamber and the enlarged section 24 of the fluidization chamber, and in this structure, the enlarged section 24 of the fluidization chamber can be located below the straight section 4 of the fluidization chamber. The fluidized particulate material located in the fluidization chamber constitutes a fluidized bed layer, and the upper surface 37 of the fluidized bed layer is located inside the fluidization chamber. An air inlet 25, a return material port 26, a discharge port 27, and an air outlet 28 are provided on the bed body 1. The air inlet 25 is communicated with the air inlet chamber 3, the return material port 26 and the discharge port 27 are both communicated with the fluidization chamber, and the air outlet 28 is communicated with the settling chamber 5.

[0048] The spray gun 2 is used for atomizing liquid materials. The spray gun 2 is installed at the top of the bed body 1 through a spherical hinge, and the spray gun 2 is arranged in one row and five columns.

[0049] The nozzle 38 of the spray gun is located above the upper surface 37 of the fluidized bed layer.

[0050] In this embodiment, the structures of the spherical hinge, the spray gun driving mechanism, and the rotary joint are the same as those in Embodiment 1 and will not be elaborated here.

[0051] During the granulation and drying process, according to parameters such as the required product particle size, the size of the upper surface 37 of the fluidized bed layer, the liquid spraying speed of the spray gun 2, and the drying rate of the liquid material, the vertical driving device drives the motor 8 to reciprocate according to a preset period T / 2. At the same time, the motor 8 drives the spray gun 2 to rotate at a uniform angular speed according to a preset period T, so as to form a continuously and periodically circulating moving atomized liquid droplet receiving area 36 in the top layer area of the fluidized bed layer. The atomized liquid droplet receiving area 36 continuously and periodically circulates along a closed-shaped trajectory. As Figure 6 shown in c, the closed shape has two orthogonal axes, and the two orthogonal axes are respectively the long axis 34 and the short axis 35. The closed shape has mirror symmetry with respect to the long axis 34 and the short axis 35.

[0052] A closed shape is a continuous and unbroken graph, and all line segments or curves are connected inside the graph without open ports. Those skilled in the art can understand that the "trajectory of the closed shape" refers to "the trajectory formed by the boundary of the closed shape".

[0053] AsFigure 6 As shown in c, in this embodiment, the major axis 34 is perpendicular to the length direction of the bed body 1. For a bed layer area of a certain size, the liquid receiving area of the atomized droplets formed in this way can cover a larger proportion of the bed area. Moreover, this way has better compatibility with the air inlet chamber, so that the flow field of the fluidized bed layer can be designed more conveniently. For example, an upward material flow is formed in the inner ring area of the liquid receiving area of the atomized droplets, and a downward material flow is formed outside the outer ring to enhance the renewal of the particles in the granulation area.

[0054] It should be noted that when the motor 8 moves vertically, it is necessary to ensure that the connecting rod 9 and the spray gun 2 are not collinear, that is, the angle between the axis of the spray gun 2 and the vertical direction needs to be greater than 0° to avoid the "dead point".

[0055] The atomized droplets of the spray gun 2 should be prevented from spraying onto the inner wall of the bed body 1 to avoid the appearance of scale on the inner wall of the bed body 1.

[0056] Within one cycle, the shape of the area covered by the liquid receiving area 36 of the atomized droplets is annular. Since the inner circle area within the inner boundary of the annulus does not receive droplet spraying, the shape of each horizontal section of the formed granulation area is also an annulus corresponding to it. Since the material particles constituting the fluidized bed layer are constantly undergoing intense backmixing in the vertical and horizontal directions, the annular boundary is dynamically changing. The dry particles in the outer region and the inner circle region of the annulus cross the annular boundary and interact with the wet sticky particles in the granulation area, accelerating the migration and renewal of the particles in the granulation area, quickly reducing the wet sticky state of the material in the granulation area and accelerating the drying speed, thus alleviating the contradiction that the drying rate of the material in the granulation area is less than the granulation speed. The annular liquid receiving area of the atomized droplets has two boundaries, an outer circle and an inner circle. Therefore, compared with the liquid receiving surface without a central airspace, the boundary area for heat and mass transfer around the granulation area formed by the annular liquid receiving area of the atomized droplets is larger, and the heat and mass transfer efficiency is higher, making the granulation-drying process more stable.

[0057] Those skilled in the art can understand that by adjusting equipment parameters, such as the atomization angle of the spray gun 2, the height of the upper surface 37 of the fluidized bed layer, etc., the shape of the area covered by the liquid receiving area 36 of the atomized droplets can be made into a solid shape.

[0058] In an existing top-down spray fluidized bed granulation dryer with a single-unit production scale for molasses yeast tail liquid, the straight section length of the fluidization chamber is 10 m, the width is 1.6 m, the upper surface of the fluidized bed layer is about 300 mm higher than the bottom of the enlarged section of the fluidization chamber, the spray gun is fixedly arranged above the bed layer, the nozzle is about 1000 mm higher than the upper surface of the bed layer, and a fixed liquid receiving area 39 of atomized droplets is formed on the upper surface 37 of the fluidized bed layer when the nozzle sprays liquid. The boundary diameter of the fixed liquid receiving area 39 of atomized droplets is 400 mm to 500 mm, and it is necessary to fixedly arrange two rows and ten columns of spray guns to cover part of the fluidized bed layer (such asFigure 7 As shown in Figure 7 , can the stable operation of the equipment be ensured. In this embodiment, the fluidized bed granulation drying method is adopted. When using a fluidized bed granulator of the same size and the same material parameters and fluidization parameters, only one row of five columns of spray guns 2 needs to be arranged. By driving the spray guns 2 continuously and periodically in a cyclic motion through the spray gun driving mechanism, the stable operation of the equipment can be ensured, and phenomena such as caking and bed collapse can be avoided.

[0059] In addition to being able to solve the contradiction that the drying rate of viscous materials is less than the granulation speed by continuously and periodically moving the liquid receiving area of the atomized droplets as in Embodiment 1, and avoid problems such as the formation of coarse particles or caking, in this embodiment, the area of the liquid receiving area covered by single-gun atomization is several times that of the existing fixed spray gun arrangement. The number of spray guns is reduced to 1 / 4, reducing the investment cost of the spray guns, accessory pipelines and control systems.

[0060] In addition, compared with the granulation drying area corresponding to the multiple fixed liquid receiving areas 39 of the atomized droplets formed when the spray guns are fixedly arranged, the granulation drying area formed when the spray guns of the present invention are working can cover multiple fixed liquid receiving areas of the atomized droplets and the void areas therebetween. Therefore, the way of moving the liquid receiving area of the atomized droplets of the present invention can cover a larger range of the bed area than the atomization method of fixedly arranging the spray guns. Specifically in this embodiment, the area of the liquid receiving area of the atomized droplets covered by a single-rod spray gun is more than 50% larger than the total area of the liquid receiving areas of the atomized droplets of four fixed spray guns. When the production capacity of the equipment remains unchanged, increasing the available bed area is equivalent to reducing the granulation drying intensity per unit area, thereby increasing the operation stability of the equipment.

[0061] Embodiment 4

[0062] The length-width ratio of the body of a conventional continuous granulation drying machine is relatively large, resulting in a relatively large increase in particle size and a wider particle size distribution range. For the production of products that require finer and more uniform particle sizes, there is a problem of low product yield, increasing the load on subsequent processing equipment such as screening, crushing, and return materials. Reducing the length-width ratio of the bed body is one of the ways to solve the above problems. However, for the upper spray and lower insert gun form, limited by the area of the liquid receiving area of the atomized droplets covered by a single gun, in order to cover the entire bed, multiple rows of spray guns need to be arranged in the width direction of the bed body, and the gun arrangement area is narrow, bringing inconvenience to system arrangement and spray gun maintenance.

[0063] As Figure 8 shown, the difference from Embodiment 3 is that in this embodiment, the length-width ratio of the bed body 1 is smaller than that of the bed body 1 in Embodiment 3. The spray guns 2 are arranged in two rows and three columns, and the long axis 34 is parallel to the length direction of the bed body 1.

[0064] In this embodiment, the atomized liquid droplet receiving area is continuously and periodically cycled along the trajectory of a closed figure to arrange the spray guns, so as to obtain a smaller aspect ratio of the bed body than that of the existing granulation bed with fixed spray gun arrangement, and this problem can be better solved.

[0065] Embodiment 5

[0066] Figure 9 、 Figure 10 Fig. 5 shows Embodiment 5 of the present utility model.

[0067] This embodiment provides a fluidized bed granulation dryer, and the material for granulation is molasses yeast tail liquid.

[0068] As Figure 9 shown, in this embodiment, the fluidized bed granulation dryer is a continuous, top-down spray type fluidized bed dryer, including a bed body 1, a spray gun 2 and a spray gun driving mechanism.

[0069] As Figure 9 shown, the cross-section of the bed body 1 is rectangular. Inside the bed body 1, an air inlet chamber 3, a fluidization chamber, an enlarged section 24 and a settling chamber 5 are successively arranged from bottom to top. A air distribution plate 6 is arranged between the air inlet chamber 3 and the fluidization chamber. In this embodiment, the fluidization chamber includes a straight section 4 of the fluidization chamber and an enlarged section 24 of the fluidization chamber, and the enlarged section 24 of the fluidization chamber is located above the straight section 4 of the fluidization chamber. It should be noted that for those skilled in the art, the specific form of the fluidization chamber is not limited to the form shown in this embodiment. For example, the fluidization chamber can be composed only of the straight section 4 of the fluidization chamber, or only of the enlarged section 24 of the fluidization chamber. In addition, the fluidization chamber can also include the straight section 4 of the fluidization chamber and the enlarged section 24 of the fluidization chamber, and in this structure, the enlarged section 24 of the fluidization chamber can be located below the straight section 4 of the fluidization chamber. The fluidized granular material located in the fluidization chamber constitutes a fluidized bed layer, and the upper surface 37 of the fluidized bed layer is located inside the fluidization chamber. An air inlet 25, a return material port 26, a discharge port 27 and an air outlet 28 are arranged on the bed body 1. The air inlet 25 is communicated with the air inlet chamber 3, both the return material port 26 and the discharge port 27 are communicated with the fluidization chamber, and the air outlet 28 is communicated with the settling chamber 5.

[0070] The spray gun 2 is used to atomize the liquid material, and the spray gun 2 is installed at the top of the bed body 1 through a spherical hinge 7. Those skilled in the art can understand that the spray gun 2 can also be pivotally connected to the top of the bed body 1.

[0071] The nozzle 38 of the spray gun is located above the upper surface 37 of the fluidized bed layer.

[0072] In this embodiment, the structure of the spherical hinge is the same as that in Embodiment 1, and will not be elaborated here.

[0073] The spray gun driving mechanism is used to drive the spray gun 2 to swing reciprocally. Specifically, asFigure 10 As shown in the figure, the spray gun driving mechanism includes a linear driving device, a sliding pin 21 and a groove rod 22. The groove rod 22 is fixedly connected to the spray gun 2. A linear sliding groove 23 is provided on the groove rod 22, and the sliding pin 21 is slidably engaged with the linear sliding groove 23. The linear driving device is used to drive the sliding pin 21 to move linearly. In this embodiment, the linear driving device uses an electric push rod 19. Those skilled in the art can understand that the linear driving device can also use a cylinder or a hydraulic cylinder. The moving direction of the sliding pin 21 intersects with the extending direction of the linear sliding groove 23.

[0074] During the granulation and drying process, according to parameters such as the required product particle size, the size of the upper surface 37 of the fluidized bed layer, the liquid spraying speed of the spray gun 2, and the drying rate of the liquid material, the spray gun 2 is driven by the spray gun driving mechanism to reciprocate periodically according to a preset reciprocating cycle and swing amplitude, so that the liquid receiving area 36 of the atomized liquid droplets moves continuously and periodically along a linear trajectory.

[0075] As Figure 9 shown in c, within one cycle, the shape of the area covered by the liquid receiving area 36 of the atomized liquid droplets is an arc-angle rectangle. The arc angles at both ends are the shape of the intersection line symmetric about the swing axis formed after the atomization area 40 intersects with the upper surface of the bed layer. Its width is equivalent to the width of the liquid receiving area formed by a single-rod fixed spray gun, and its length is equivalent to extending the liquid receiving area formed by a single-rod fixed spray gun along the length direction. The liquid receiving area formed by a single-rod spray gun not only covers the liquid receiving areas formed by multiple fixed spray guns (as Figure 11 shown), but also fills the gaps between these liquid receiving areas, achieving a larger coverage ratio of the bed layer area, thus bringing better granulation and drying stability, reducing the number of spray guns and the corresponding investment, and improving the overall operation stability or production capacity of the equipment at the same time.

[0076] As Figure 9 shown in c, in this embodiment, the linear trajectory is perpendicular to the length direction of the bed body 1. For a bed layer area of a certain size, the liquid receiving area of the atomized liquid droplets formed in this way can cover a larger proportion of the bed layer area, and this way has better compatibility with the air inlet chamber, and can more conveniently design the flow field of the fluidized bed layer to enhance the renewal of particles in the granulation area. When it is necessary to reduce the aspect ratio of the bed body for the same purpose as described in Embodiment 3, in this embodiment, when the spray gun is fixed, four rows and five columns of spray guns need to be arranged to generally cover the fluidized bed layer (as Figure 11 shown). In this embodiment, only one row and five columns of spray guns 2 need to be arranged to enable the atomization area 40 to cover the entire bed layer, reducing the number of spray guns 2 arranged, and obtaining a lower aspect ratio at the same time.

[0077] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A fluidized bed granulation dryer, characterized in that: Comprising a bed body (1), a spray gun (2) and a spray gun driving mechanism, an air inlet chamber (3), a fluidization chamber and a sedimentation chamber (5) are successively arranged in the bed body (1) from bottom to top, and a air distribution plate (6) is arranged between the air inlet chamber (3) and the fluidization chamber; the spray gun (2) is installed at the top of the bed body (1) through a ball hinge (7); the spray gun driving mechanism is used for driving the spray gun (2) to rotate and / or swing, the spray gun driving mechanism comprises a vertical driving device, a motor (8) and a connecting rod (9), the vertical driving device is used for driving the motor (8) to move vertically, the axis of the output shaft of the motor (8) is in the vertical direction and passes through the center of the ball hinge (7), and the two ends of the connecting rod (9) are respectively pivotally connected to the output shaft of the motor (8) and the spray gun (2).

2. The fluidized bed granulation dryer according to claim 1, wherein: A rotary joint (10) is installed on the spray gun (2), and materials and atomizing medium enter the spray gun (2) through the rotary joint (10).

3. The fluidized bed granulation dryer according to claim 2, characterized in that: The rotary joint (10) is coaxially and rotatably sleeved outside the spray gun (2); a material channel (11) and an atomizing medium channel (12) are arranged in the spray gun (2), and a material communication port (13) and an atomizing medium communication port (14) communicated with the material channel (11) and the atomizing medium channel (12) respectively are arranged on the spray gun (2); a material ring cavity (15) and an atomizing medium ring cavity (16) communicated with the material communication port (13) and the atomizing medium communication port (14) respectively are arranged in the rotary joint (10), and a material input port (17) and an atomizing medium input port (18) communicated with the material ring cavity (15) and the atomizing medium ring cavity (16) respectively are arranged on the rotary joint (10).

4. The fluidized bed granulation dryer according to claim 1, characterized in that: The included angle between the axis of the spray gun (2) and the vertical direction is greater than 0°.

5. A fluidized bed granulation dryer, characterized in that: Comprising a bed body (1), a spray gun (2) and a spray gun driving mechanism, an air inlet chamber (3), a fluidization chamber and a sedimentation chamber (5) are successively arranged in the bed body (1) from bottom to top, and a air distribution plate (6) is arranged between the air inlet chamber (3) and the fluidization chamber; the spray gun (2) is hinged to the top of the bed body (1); the spray gun driving mechanism is used for driving the spray gun (2) to swing, the spray gun driving mechanism comprises a linear driving device, a sliding pin (21) and a groove rod (22), the groove rod (22) is fixedly connected with the spray gun (2), a linear sliding groove (23) is arranged on the groove rod (22), the sliding pin (21) is in sliding fit with the linear sliding groove (23), the linear driving device is used for driving the sliding pin (21) to move linearly, and the moving direction of the sliding pin (21) intersects with the extending direction of the linear sliding groove (23).

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