An internal heat exchange fluidized bed dryer

Abstract

An internal heat exchange fluidized bed dryer relates to the technical field of processing equipment for drying, cooling, and granulating wet raw materials. The bed is respectively provided with a dust exhaust pipe, a feed port, and a discharge port. An air distribution chamber, an air distribution mesh plate, a fluidizing chamber, and a separation chamber are sequentially arranged from bottom to top within the bed. A dry-wet material mixing area and a fluidizing area are provided within the fluidizing chamber. A through-hole screen is also provided to separate the dry-wet material mixing area from the fluidizing area. The dry-wet material mixing area is arranged corresponding to the feed port, and an internal heat exchanger is provided within the fluidizing area. During operation, the dry-wet material mixing area can effectively avoid the defects of lumps getting stuck and adhering to the interior of the internal heat exchanger, as well as accumulation, fire, and explosion. More internal heat exchanger area can be arranged, achieving the effects of increased production capacity, reduced energy consumption, and stable operation, thereby overcoming the defects of the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of processing equipment for drying, cooling and granulating wet raw materials, in particular to the technical field of continuous internal heat exchange fluidized bed drying. Background Art

[0002] Fluidized bed drying technology: Masterbatch (seed crystals, solid raw materials) is introduced into the fluidized bed through a feed system or manually. Hot process air is introduced into the bottom of the fluidized bed, causing the masterbatch to form a specific fluidized state on the air distribution screen of the fluidized bed. The material particles form a specific gradient from the inlet to the outlet. Passing through different fluidized bed configurations, continuous drying can be achieved. Continuous drying equipment can also be used as a batch drying system.

[0003] Continuous drying function: From the inlet to the outlet, the fluidized bed utilizes the wind plate design and the compartment structure to achieve that at different positions, the temperature decreases from high to low according to the specific drying characteristics of the material, and the moisture content of the material gradually decreases, which can achieve the most economical energy consumption and excellent product quality. The above functions can be equipped with a special control system, internal heating system, air intake system, and process formula to reach a new height of the combination of current technology and equipment. In particular, the use of the internal heat exchanger has a particularly good energy-saving effect and also has the effect of calcining to achieve some materials containing crystal water. The following processes can be realized: the process of continuous drying of solid finished products and materials with high moisture absorption; the process of continuous preparation of granules and drying of powdered raw materials; the process of continuous drying and cooling of granular wet raw materials; the continuous drying process of crystalline materials.

[0004] Characteristics of continuous drying: Because it is continuous production, the product process has good repeatability and high production efficiency; when it is suitable for continuous drying and granulation, the final product can be dust-free and have excellent performance; for those who do not want manual participation in the intermediate process and prevent pollution, continuous type is the best choice; low energy consumption; compact structure; because the material layer temperature can be low, the safety standard is high, and it is also suitable for the treatment of heat-sensitive materials; reliable operation; high evaporation intensity, and the volume is 1 / 15 to 1 / 30 of the spray drying tower; suitable for continuous drying and granulation of sticky materials and highly hygroscopic materials; especially when the output is relatively large, compared with batch equipment, it has absolute advantages in energy consumption and quality.

[0005] In the prior art, the wet raw materials can be processed in the form of loose or agglomerated wet materials by centrifuges, filter presses, concentration evaporators, mixers, etc. When the wet raw materials are dried in a fluidized bed, the following disadvantages often occur when using a conventional internal heat exchange fluidized bed:

[0006] After the wet material enters the fluidized bed, it does not have time to dry and disperse, causing it to clump in the bed and stick to the air distribution mesh and shell wall, causing fluidization to be destroyed and the bed to become dead. In particular, as the continuous production time increases, the air distribution mesh is blocked and production cannot be continued.

[0007] Insufficient mixing time between the wet material and the fluidized material in the bed results in the formation of lumps, which results in high moisture content and numerous lumps in the material moving to the side bins. This can easily lead to uneven moisture content in the small particles in the finished product. More importantly, when the physical size of the small lumps is close to the internal size of the internal heat exchanger, they may become stuck inside the internal heat exchanger, causing local non-fluidization in the fluidized bed. The more they get stuck, the more severe the non-fluidization becomes, forming a vicious cycle. In addition, the stuck and adhered non-fluidized areas experience material friction and self-accumulation and temperature rise. The temperature of the material in this area, especially the center temperature, will continue to rise until it reaches the softening point of the material and adheres to the internal heat exchanger, air distribution screen and shell wall, reaching the ignition point of the material, causing fire or explosion of the equipment. An additional risk is that when the size of the particles and lumps is larger than the internal size of the internal heat exchanger, they have no chance of exiting from the discharge port below and instead form a bridge above the internal heat exchanger, making fire and explosion more likely to occur. Summary of the Invention

[0008] The purpose of the present invention is to provide an internal heat exchange fluidized bed drying and cooling machine which can effectively prevent lumps generated during operation from getting stuck and accumulating inside the internal heat exchanger and avoid the air distribution screen from being wet, adhered and blocked.

[0009] The present invention includes a bed body, which is respectively provided with a dust exhaust pipe, a feed port and a discharge port. An air distribution chamber, an air distribution mesh plate, a fluidizing chamber and a separation chamber are sequentially provided in the bed body from bottom to top. The present invention is characterized in that a dry and wet material mixing area and a fluidizing material area are provided in the fluidizing chamber, and a through-hole baffle is also provided to isolate the dry and wet material mixing area from the fluidizing material area. The dry and wet material mixing area is arranged corresponding to the feed port, and an internal heat exchanger is provided in the fluidizing material area.

[0010] During operation, the original wet material enters the mixed material layer first. The wet material entering the dry-wet material mixing area is first dispersed and preliminarily dried by the material in the mixed material layer. A relatively high hot air temperature can be used in this area. After the initial drying, it can be well fluidized without producing large lumps, thereby reducing the stickiness of the material caused by the simultaneous action of moisture and heat, and reducing or avoiding the ability of material adhesion. At this time, the material in the dry-wet material mixing area is not easy to adhere to the through-hole baffle or the air distribution mesh plate, and the material then passes through the through-hole baffle into the surrounding fluidized material area. Therefore, even if there are lumps, the dry and wet materials are kept away from the through-hole baffle because of the effect of the through-hole baffle. The lumps in the mixing area cannot enter the adjacent fluidized material area with a heat exchanger. Inside the internal heat exchanger, these lumps are reduced or even eliminated, and large lumps are completely prevented from contacting the internal heat exchanger, thereby avoiding the internal heat exchanger from being stuck or adhering to produce lumps, which may lead to poor fluidization, material friction, material accumulation and heating, and fire and explosion accidents. The lumps blocked in the dry and wet material mixing area can be slowly ground during operation due to the action of the fluidized material, and those that cannot be ground can be regularly shut down for cleaning, thereby ensuring stability during production and achieving the purpose of the present invention.

[0011] Because an internal heat exchanger is provided in the fluidized material zone, the number of lumps in the fluidized material zone is reduced or even eliminated, the adhesion phenomenon in the fluidized material zone is reduced or eliminated, and the fluidization resistance in the internal heat exchange fluidized zone is reduced, so that more internal heat exchanger area can be arranged to the maximum extent in terms of physical size, providing more efficient internal heat exchange heating and cooling capacity, thereby further achieving the invention's purpose of increasing production capacity, reducing energy consumption, and stabilizing operation.

[0012] Furthermore, the perforated screen of the present invention is a vertical perforated screen. The dry and wet material mixing area is arranged within the area enclosed by the vertical perforated screen, the air distribution screen, and the bed, i.e., the air distribution screen is directly below the mixing layer area. This structure is simple. The presence of the dry and wet material mixing area reduces or prevents hot and humid material from adhering to the air distribution screen. The presence of the vertically arranged perforated screen prevents lumps from entering the internal heat exchanger and causing them to become stuck or adhere. Preferably, a lump discharge port is provided at the bottom of the dry and wet material mixing area to discharge lumps or material in the fluidization chamber.

[0013] Alternatively, the through-hole screen further includes a transverse through-hole screen, which is arranged at the lower end of the vertical through-hole screen, and a spacing is provided between the transverse through-hole screen and the air distribution screen. A dry-wet material mixture zone is formed between the through-hole screen and the inner wall of the bed, which can further completely prevent the wet material from adhering to the air distribution screen, accumulating on the air distribution screen, and being susceptible to high temperatures. This spacing serves as a safety distance, effectively preventing lumps above the through-hole screen from directly contacting the high-temperature areas of the air distribution screen, thereby preventing the ignition or explosion of the lumps caused by high temperatures. At the same time, in order to increase the thickness of the dry-wet material mixture zone, the safety distance between the through-hole screen and the air distribution screen can be minimized, and any known physical fixing scheme can be used.

[0014] In addition, the transverse through-hole screen of the present invention can also be arranged at an angle, with the angle between the transverse through-hole screen and the horizontal line being 0.5 to 30 degrees. This design facilitates the movement of the agglomerates above the through-hole screen toward the discharge port, thereby achieving a better effect.

[0015] The holes of the transverse through-hole screen of the present invention are arranged obliquely. Using a diagonally arranged grid-type through-hole screen or a plate-type through-hole screen with lateral holes allows fluidizing air and fluidized material to pass through the transverse through-hole screen, effectively blowing the material toward the outlet. However, using a vertical grid-type through-hole screen has a less effective ability to do this and requires an oblique arrangement.

[0016] Furthermore, the through-hole diameter of the through-hole blocking net of the present invention is 4 to 100 mm; the internal heat exchanger is a shell-and-tube heat exchanger or a plate heat exchanger, the spacing between adjacent tubes of the shell-and-tube heat exchanger is 4 to 100 mm, and the spacing between adjacent internal heat plates of the plate heat exchanger is 4 to 100 mm.

[0017] Usually, the internal dimensions of the internal heat exchanger are relatively large, and many of them are close to zero dimensions for installation and fixed use. The smaller the through-hole size of the through-hole blocking net, the more lumps can be blocked, and the more the purpose of the present invention can be achieved. However, if the through-hole size of the baffle is too small, it will increase the fluidization resistance, cause the risk of material adhesion on the through-hole blocking net, and even produce lumps. Therefore, the through-hole size of the through-hole blocking net cannot be too small. When the through-hole size of the through-hole blocking net is close to the internal representative size of the internal heat exchanger, the lumps in the spray fluidization chamber can be blocked.

[0018] A gap is provided between the lower end of the vertical through-hole screen and the upper surface of the air distribution screen. This gap is for the purpose of facilitating the installation of the vertical through-hole screen and preventing interference with the air distribution screen. On the other hand, small clumps of dry and wet materials that cannot boil in the mixed area but can still be blown can pass through this gap into the adjacent fluidized material area and be gradually blown into the discharge port by the air distribution screen, thereby ensuring continuous and stable operation of the fluidized bed. Preferably, this gap is adjustable during operation.

[0019] The present invention can also be provided with a granulating device at the feed inlet. On the one hand, this can improve the dispersion effect of the wet material entering the fluidized bed and reduce the possibility of agglomeration. On the other hand, it can also play the role of converting the wet raw material into small particles and preventing the small particles from agglomerating into large agglomerates, thereby obtaining a small particle finished product, and realizing the fluidized bed functions of drying, drying and cooling.

[0020] A mechanical breakup device is installed within the dry and wet material mixing area. In addition to facilitating the mechanical breaking of lumps, it also increases the surface spread of the wet material and the bulk density of the product, resulting in a smoother surface and more rounded particles. The breakup device is preferably located in the lower middle portion of the dry and wet material mixing area. Temperature-adjustable process air can also be introduced into the breakup and granulation device, entering the fluidized bed simultaneously with the wet material, further dispersing the wet material and reducing the possibility of clumping within the dry and wet material layers.

[0021] A cleaning device is arranged above the air distribution mesh plate to drive the lumps to the discharge port. At regular intervals, it reciprocates once to clean the generated lumps into the lumps discharge port in time, and is used to discharge the lumps that cannot be broken, so as to ensure long-term continuous production.

[0022] In addition, in order to form a continuous internal heat exchange fluidized bed drying, cooling and granulating machine with continuous raw wet material feeding and continuous discharge, the present invention can also be provided with a return port on the shell. At this time, various environmental protection devices such as external cyclone separators, built-in bag dust collectors, external bag dust collectors, external wet collectors and deodorizers can be selectively set according to specific needs. The materials collected by each dust collector can be processed separately or sent to the return port or feed port through the return device to participate in continuous granulation and drying. It is preferred that they are returned to the system inlet and enter the inlet's granulation device after mixing the dry powder with the raw wet material.

[0023] In summary, the above technical solutions of the present invention can effectively prevent the lumps generated by wet raw materials from getting stuck inside the internal heat exchanger and accumulating and adhering to the air distribution screen during the operation of the internal heat exchange fluidized bed, thereby avoiding fire and explosion. At the same time, more internal heat exchanger area can be arranged and the energy consumption of the dryer can be reduced, thereby achieving the effects of increased production capacity, reduced energy consumption and stable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic elevation view of the present invention.

[0025] Figure 2 for Figure 1 A side view schematic diagram of a fluidizing chamber with an internal heat exchanger.

[0026] Figure 3 for Figure 1 A side view schematic diagram of a fluidized chamber for mixing dry and wet materials.

[0027] Figure 4 for Figure 1 Another side view schematic diagram of the dry and wet material mixing fluidization chamber.

[0028] Figure 5 It is another elevational schematic diagram of the present invention.

[0029] Figure 6 、 Figure 7 for Figure 5 Two side schematic diagrams of .

[0030] Figure 8 This is a third schematic elevation view of the internal heat exchange fluidized bed dryer of the present invention.

[0031] Figure 9a This is a structural diagram of a vertical grid-type through-hole retaining net.

[0032] Figure 9b This is a structural diagram of an inclined grid-type through-hole retaining net.

[0033] Figure 9c This is a structural diagram of a plate-type through-hole retaining net.

[0034] Figure 10 This is a schematic diagram of the channel structure of the shell and tube internal heat exchanger of the present invention.

[0035] Among them: 1 is the air distribution chamber, 2 is the air distribution screen, 3 is the fluidizing chamber, 4 is the dry and wet material mixing area, 5 is the separation chamber, 6 is the dust exhaust pipe, 7 is the horizontal through-hole screen, 8 is the internal heat exchanger, 9 is the vertical through-hole screen, 10 is the cyclone separator, 11 is the return port, 12 is the feed port, 13 is the discharge port, 14 is the disintegration and granulation device, 15 is the return material fan, 16 is the bag dust collector, 17 is the height distance, 18 is the through-hole size of the through-hole screen, 19 is the representative size of the internal heat exchange, 20 is the partition plate, 21 is the angle between the through-hole screen and the horizontal line, 22 is the mechanical energy knife, 23 is the grid-type through-hole screen, 24 is the plate-type through-hole screen, 25 is the mechanical cleaning device, 26 is the hot air inlet, 27 is the bed, 28 is the block material discharge port, 29 is the channel, 30 is the mixing device, and 31 is the fluidizing area. DETAILED DESCRIPTION

[0036] like Figures 1 to 7 As shown: an internal heat exchange fluidized bed granulating, drying and cooling machine, the upper part of the bed 27 is provided with a raw material inlet 12, the lower part is provided with a discharge port 13, the main body of the bed 27 is divided into an air chamber 1 from bottom to top (can be used Figure 3 The downwind air intake method shown in the following example can also be used. Figure 2 The side air inlet mode shown in the figure), the air distribution screen 2 (can adopt the existing known technology, preferably the technology with low air distribution resistance, side blowing force and no leakage), the fluidizing chamber 3 (can be a straight section, a cone, a straight section plus a cone structure), the separation chamber 5 (can be a straight section, a cone, a straight section plus a cone structure), the upper part of the bed 27 is provided with a dust exhaust pipe 6 (can be Figure 6 Directly above or Figure 7 The side air outlet structure shown in the figure) is formed by the fluidizing chamber 3 and the separation chamber 5 being interconnected spaces that are continuous with each other.

[0037] The fluidizing chamber 3 is divided into a dry and wet material mixing area 4 and a fluidizing material area 31 , which are separated by a vertical through-hole baffle 9 , and the dry and wet material mixing area 4 should be arranged with the feed port 12 .

[0038] The present invention is characterized in that: a plurality of internal heat exchangers 8 are provided in the fluidized material zone 31 ( Figure 5As shown, the block material is discharged near the discharge port, and the internal heat exchanger may not be provided. A horizontal through-hole screen 7 or a vertical through-hole screen 9 is provided below the feed port 12 (in order to prevent the block material from getting stuck on the horizontal through-hole screen 7 or the vertical through-hole screen 9, the horizontal through-hole screen 7 or the vertical through-hole screen 9 may be provided with an elastic solution, which can play a self-cleaning role during operation). A dry-wet material mixing area 4 is also provided below the feed port 12. The raw wet material falling from the feed port 12 first enters the dry-wet material mixing area 4, and then passes through the horizontal through-hole screen 7 or the vertical through-hole screen 9 to enter the adjacent fluidized material area 31. When the dry-wet material mixing area 4 is connected to the fluidized material area 31, it can also pass through the gap between the vertical through-hole screen 9 and the air distribution screen 2. This gap is preferably adjustable in size during operation.

[0039] like Figures 1 to 8 The several solutions shown can selectively set up an external cyclone separator 10 and a built-in bag dust collector 16 (such as Figure 6 As shown) or external bag dust collector, external wet collector and deodorization and other environmental protection devices, the materials collected by each dust collector can be processed separately or through return material, such as turning off the fan 15 to discharge the material, and then sent to the feed port 12 or the return port 11, preferably sent to the mixing device 30 that can mix dry and wet materials for mixing, and then enter the bed 27 through the granulating device 14. The air inlet chamber, fluidization chamber and separation chamber of each unit can correspond to each other one by one or not, and there may be a partition plate 20 inside, or there may not be a partition plate 20. Because of the fluidization wind speed in the bed 27, fine dust will be discharged from the bed 27, and the material discharged from the discharge port 13 does not contain fine dust, as shown Figure 5 As shown, cold process air is introduced from the hot air inlet 26 on the side of the discharge port 13 , so the material is cooled first and then discharged from the discharge port 13 .

[0040] like Figure 1 Figure 8 In the scheme shown, the vertical through-hole baffle 9, the air distribution mesh plate 2, and the inner wall of the bed 27 form a dry and wet material mixing area 4. The vertical through-hole baffle 9 can be connected to the air distribution mesh plate 2, or it can be at a distance from the air distribution mesh plate 2. The distance can be adjusted. Figure 8 You can also press Figure 5 As shown, a transverse through-hole baffle 7 is added. There is a distance between the transverse through-hole baffle 7 and the air distribution mesh plate 2. Its function is to prevent the agglomerates in the dry-wet material mixture area 4 from directly contacting the air distribution mesh plate 2. The transverse through-hole baffle 7 and the vertical through-hole baffle 9 are physically fixed on the internal heat exchanger 8 or the inner wall of the bed 27 or are connected and fixed to each other.

[0041] like Figure 1 Figure 3 Figure 4 Figure 5 Figure 8As shown, a breaking and granulating device 14 is connected above the feed port 12 (to increase the effect, 2-3 such devices can be connected in series), and in order to break up possible lumps in the dry and wet material mixing area 4, a mechanical breaking device 22, preferably a rotating blade, can be provided.

[0042] The through-hole size 18 of the transverse through-hole screen 7 or the vertical through-hole screen 9 is close to the internal representative size 19 of the internal heat exchanger. The internal representative size is the average size between adjacent tubes of a shell-and-tube heat exchanger or the average size between adjacent internal heat plates of a plate heat exchanger. The through-hole size 18 is 4-100 mm, and the internal representative size 19 is 4-100 mm. The ratio between the two is between 100-400%, preferably between 100-150%.

[0043] like Figure 4 As shown, the transverse through-hole screen 7 is arranged in an inclined manner toward the discharge port 13, and the angle 21 between the transverse through-hole screen 7 and the horizontal line is 0.5-30 degrees. The discharge port 13 can be arranged in the length or width direction of the bed 27, and several discharge ports 13 can also be provided as needed. Figure 3 As shown in FIG, a mechanical energy knife device 22 can be provided above the air distribution mesh plate 2. Figure 4 As shown, a mechanical cleaning device 25 can also be provided above the transverse through-hole baffle 7. The direction of cleaning is to discharge the blocks into the block discharge port 28. The block discharge port 28 is preferably connected to the granulator discharge port 13. Several block discharge ports 28 can be provided.

[0044] like Figures 9a-9c As shown, the through hole blocking net of the present invention (whether it is a horizontal through hole blocking net or a vertical through hole blocking net) can optionally adopt a grid structure, and the grid can be a vertical grid type through hole blocking net 23, such as Figure 9a As shown, 18 is the hole size of the through-hole screen; the grille can be an inclined grille type through-hole screen 23, such as Figure 9b As shown, 18 is the through hole size of the through hole block net; the through hole block net can also be a plate-type through hole block net 24, such as Figure 9c As shown, 18 represents the size of the holes in the through-hole screen. A wire mesh structure can also be used to achieve the objectives of the present invention. Preferably, when the fluidizing air and fluidized material pass through the through-hole screen, the through-hole screen is capable of blowing the material toward the outlet. A diagonally arranged grid-type through-hole screen or a plate-type through-hole screen with lateral holes is used.

[0045] like Figure 10 The solution shown is characterized in that the shell and tube heat exchanger 8 is a structure with a channel, the function of the channel is to discharge the possible bulk material in the internal heat fluidization chamber 3, and the channel 29 can also be Figure 2 Figure 6The horizontal arrangement shown in the figure is characterized in that the channel 29 is formed between the internal heat exchanger 8 and the air distribution mesh plate 2. The additional effect of the channel 29 is that it can improve the internal heat transfer coefficient and achieve the effect of increasing production and reducing consumption. The channel is not a necessary solution in the present invention, but some small channels will be automatically formed inside the normal internal heat exchanger 8 through manufacturing and installation, and the effect is not great. The specially arranged channel facing the discharge port has a relatively obvious effect. The channel gap here is more than twice the through-hole size 18, and preferably between 2-100 times.

[0046] In this device scheme, the preferred data are: the vertical distance between the internal heat exchanger 8 and the air distribution screen 2 is 10-400 mm; the height of the fluidizing chamber 3 is 300-3000 mm; the height distance 17 is 50-500 mm; the through-hole size 18 of the through-hole baffle is 4-100 mm; and the internal representative size 19 of the internal heat exchanger 8 is 4-100 mm.

[0047] Working process description:

[0048] During operation, there is first a fluidized material layer 3 in the bed body 27 (the height can be lowered at the beginning, and the height during normal operation is the position shown in the figure). The raw wet material enters the fluidized bed from the feed port 12, and most of the raw wet material first falls into the dry and wet material mixing area 4. At the same time, a certain flow of hot air is supplied from the hot air inlet 26. The hot air enters the air distribution chamber 1 and passes through the air distribution mesh plate 2. The material is blown by the hot air flow and is heated by the internal heat exchanger 8. It is in a boiling state in the fluidizing chamber 3. In the separation chamber 5, the particles are separated from the gas and solid and settled. The gas after heat exchange is discharged from the dust exhaust pipe 6, and the settled particles fall into the fluidized bed and continue the working process. The required heat is provided by the hot air flow provided by the hot air inlet 26 and the internal heat exchanger 8, thereby reducing the amount of hot air flow and playing an energy-saving role.

[0049] The internal heat exchanger 8 can adopt a shell-and-tube or plate heat exchanger and other solutions. Steam, hot water, thermal oil, cold water and other known heat exchange media can be introduced into the internal heat exchanger.

[0050] When the material enters the adjacent fluidized material zone 31 from the dry and wet material mixing zone 4, it can pass through the vertical through-hole blocking net 9 or through the gap between the vertical through-hole blocking net 9 and the air distribution screen 2. Preferably, the size of this gap can be adjusted during operation.

[0051] There is a height distance 17 between the transverse through-hole blocking net 7 and the air distribution screen plate 2. The transverse through-hole blocking net 7 is physically fixed on the inner wall of the internal heat exchanger 8 or the bed 27. Because of the height distance 17, the lumps blocked by the transverse through-hole blocking net 7 do not come into contact with the high-temperature parts of the internal heater 8, thereby avoiding fire and explosion.

[0052] During operation, the horizontal through-hole blocking net 7 or the vertical through-hole blocking net 9 blocks the oversized lumps in the dry-wet material mixture area 4 to prevent them from getting stuck and adhering to the internal heat exchanger 8 and blocking the air distribution screen 2, thereby ensuring normal fluidization and the normal operation of the internal heat exchanger 8, thereby avoiding poor fluidization, fire and explosion accidents caused by these lumps.

[0053] The reasons why lumps may appear in the dry-wet material mixing area 4 include the instantaneous excessive amount of raw wet material entering, the failure of the entering wet material to disperse, and poor local fluidization in the dry-wet material mixing area 4. A horizontal through-hole baffle 7 or a vertical through-hole baffle 9 is used to block these lumps outside the internal heat exchanger 8, thereby reducing or avoiding lumps and poor fluidization caused by material adhesion and jamming inside the internal heat exchanger 8.

[0054] The lumps blocked in the dry-wet material mixture area 4 can be cleaned by regular shutdown, or discharged from the block discharge port 28, or crushed by a mechanical energy cutter 22, or regularly cleaned by a mechanical energy cleaning device 25 and discharged from the channel 29 to the discharge port 13, thereby ensuring stability during production.

[0055] Because the number of lumps in the fluidized layer 3 of the internal heat exchanger is reduced or even eliminated, the adhesion phenomenon of the internal heat exchanger layer 3 is reduced or eliminated, and the fluidization resistance of the internal heat exchange fluidized layer 3 is reduced, so that more internal heat exchanger 8 area can be arranged to the maximum extent in terms of physical size, providing more efficient internal heat exchange heating and cooling capacity, thereby further achieving the invention's purpose of increasing production capacity, reducing energy consumption, and stabilizing operation.

[0056] In the continuous internal heat exchange fluidized bed granulation, drying and cooling scheme (such as Figure 5-Figure 8 As shown in the figure, the formed particles fall onto the air distribution mesh plate 2. Under the blowing of the hot air flow or the guidance of the air distribution mesh plate 2, the formed materials move to the discharge port 13 and are discharged. The blowing of the hot air flow separates the materials with smaller particles from the materials with larger particles in the separation chamber 5. The dust materials rise with the hot air flow and enter the dust exhaust pipe 6 and the cyclone separator 10 in turn. After separation in the cyclone separator 10, the gas enters the downstream process. The dust materials are collected from the cyclone separator by the return material shut-off fan 15 and then passed to the inlet mixing device 30 under the action of the return material device for mixing to form a soft material. After passing through the granulating device 14, they enter the bed body and continue to participate in the drying operation.

[0057] In the continuous and discontinuous internal heat exchange fluidized bed granulation, drying and cooling schemes, the devices numbered 10-30 can be selectively set according to needs.

[0058] When a relatively short internal heat exchanger 8 is further arranged below the horizontal through-hole blocking net 7, there is a height distance 17 between the through-hole blocking net 7 and the uppermost heat exchange part of the internal heat exchanger 8. Because of the height distance 17, the lumps blocked by the through-hole blocking net 7 do not come into contact with the high-temperature part of the internal heater 8, thereby avoiding fire and explosion.

[0059] Temperature-adjustable process air can be introduced into the granulating device 14 and enter the fluidized bed 27 synchronously with the raw wet materials, thereby better dispersing the raw wet materials and further reducing the possibility of agglomeration and lumps in the dry and wet material layers.

[0060] To sum up, after adopting the above schemes, it is possible to avoid lumps getting stuck in the internal heat exchanger 8, lumps being adhered, materials adhering to the air distribution mesh plate 2, and the resulting material accumulation, fire, and explosion accidents, and the internal heater 8 can be arranged with as much heating area as possible to reduce the energy consumption of the fluidized bed, achieve the effects of increased production capacity, reduced energy consumption, and stable operation, and avoid the defects of the background technology.

[0061] The terms used in the above implementation modes and arrangements of the present invention are all based on the prior art.

Claims

1. An internal heat exchange fluidized bed dryer, comprising a bed, the bed being provided with a dust exhaust pipe, a feed port, and a discharge port, and the bed being provided with an air distribution chamber, an air distribution mesh plate, a fluidizing chamber, and a separation chamber in order from bottom to top, characterized in that: The fluidizing chamber is provided with a dry and wet material mixing area and a fluidizing material area, and a vertical through-hole screen is provided to separate the dry and wet material mixing area and the fluidizing material area. The dry and wet material mixing area is arranged corresponding to the feed inlet, and an internal heat exchanger is provided in the fluidizing material area. The vertical through-hole blocking net allows materials to pass through and can prevent agglomerates in the dry-wet material mixing area from entering the fluidized material area.

2. The internal heat exchange fluidized bed dryer according to claim 1, characterized in that: It also includes a transverse through-hole blocking net, which is arranged at the lower end of the vertical through-hole blocking net; a distance is set between the transverse through-hole blocking net and the air distribution screen.

3. The internal heat exchange fluidized bed dryer according to claim 2, characterized in that: The transverse through-hole blocking net is arranged obliquely, and the angle between the transverse through-hole blocking net and the horizontal line is 0.5-30 degrees.

4. The internal heat exchange fluidized bed dryer according to claim 2 or 3, characterized in that: The through holes of the transverse through hole blocking net are arranged obliquely.

5. The internal heat exchange fluidized bed dryer according to claim 1, characterized in that: The through hole diameter of the through hole blocking net is 4 to 100 mm; the internal heat exchanger is a shell and tube heat exchanger or a plate heat exchanger, the spacing between adjacent tubes of the shell and tube heat exchanger is 4 to 100 mm, and the spacing between adjacent internal heat plates of the plate heat exchanger is 4 to 100 mm.

6. The internal heat exchange fluidized bed dryer according to claim 1, characterized in that: A distance is set between the lower end of the vertical through-hole blocking net and the upper surface of the air distribution screen.

7. The internal heat exchange fluidized bed dryer according to claim 1, characterized in that: A breaking and granulating device is set at the feed inlet.

8. The internal heat exchange fluidized bed dryer according to claim 1, characterized in that: A mechanical disintegrating device is installed in the dry and wet material mixing area.

9. The internal heat exchange fluidized bed dryer according to claim 1, characterized in that: A cleaning device for driving the block materials toward the discharge port is arranged above the air distribution mesh plate.

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