A kiln waste heat utilization device and a rotary kiln system

Abstract

The present application relates to the technical field of kiln waste heat utilization, and discloses a kiln waste heat utilization device and a rotary kiln system, which comprise an outside cylinder waste heat utilization assembly, the outside cylinder waste heat utilization assembly comprises a shell and a pushing piece, the shell is arranged on the kiln cylinder of the calcining kiln, a processing cavity is formed between the shell and the kiln cylinder, the shell is provided with a first feeding port and a first discharging port which are communicated with the processing cavity, the pushing piece is fixed to the outer wall of the kiln cylinder and is arranged in the processing cavity, and the pushing piece is used for pushing the material to move from the first feeding port to the first discharging port. When the phosphogypsum material is treated, the phosphogypsum material is introduced into the processing cavity, the rotary kiln drives the pushing piece to rotate, the pushing piece pushes the phosphogypsum material to move in the processing cavity, the surface of the hot kiln cylinder exchanges heat with the phosphogypsum material through contact, and the heat is transferred to the phosphogypsum material to dehydrate and dry the phosphogypsum material; the kiln waste heat is actively recovered as a heat source for phosphogypsum modification.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology outside kilns, specifically to a waste heat utilization device and a rotary kiln system outside kilns. Background Technology

[0002] Phosphogypsum is a bulk industrial byproduct of gypsum produced during the wet-process phosphoric acid production process. Its main component is calcium sulfate dihydrate (CaSO4·2H2O). Currently, one of the key ways to utilize phosphogypsum resources is to convert it into hemihydrate gypsum (CaSO4·0.5H2O) or anhydrous gypsum (CaSO4) with cementing properties through heat treatment, i.e., building gypsum powder.

[0003] In traditional calcination processes, phosphogypsum is directly heated using specialized thermal equipment such as calcining kilns, fluidized bed furnaces, and woks. This means the heat generated by fuel combustion directly contacts the phosphogypsum material, heating and dehydrating it. This process consumes large amounts of primary energy sources such as coal and natural gas to provide the heat for calcination, resulting in energy costs accounting for a very high proportion of total production costs and severely impacting the market competitiveness of phosphogypsum resource-based products.

[0004] These processes require a large amount of fuel, such as coal and natural gas, to provide the heat source needed for calcination, resulting in high processing costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a device for utilizing waste heat outside the kiln and a rotary kiln system, thereby solving the technical problems in the prior art.

[0006] To achieve the above-mentioned technical objectives, the present invention provides a kiln external waste heat utilization device, comprising: An external waste heat utilization component includes a shell and a pusher. The shell is configured to be fitted onto the kiln shell of a calcining kiln. A processing cavity is formed between the shell and the kiln shell. The shell has a first feed inlet and a first discharge outlet that communicate with the processing cavity. The pusher is configured to be fixed to the outer wall of the kiln shell and built into the processing cavity, and is used to push the material from the first feed inlet to the first discharge outlet.

[0007] In one embodiment, the pusher includes a plurality of push plates, which are distributed at intervals along the circumference and axial direction of the kiln shell. The push plates are spiral-shaped and are all coaxially arranged with the kiln shell.

[0008] In one embodiment, the bottom of the outer shell is arc-shaped and configured to be coaxial with the kiln cylinder, and the size of the outer shell gradually increases from bottom to top.

[0009] In one embodiment, there are multiple external waste heat utilization components, which are spaced apart along the axial direction of the kiln cylinder, and the first feed inlet and first discharge outlet of the outer shell of the multiple external waste heat utilization components are connected in series from end to end.

[0010] In one embodiment, the external waste heat utilization device further includes a flue gas waste heat utilization component, which is disposed in the kiln head and / or kiln tail of the calcining kiln. The flue gas waste heat utilization component includes a conveying pipe and a pusher screw. The conveying pipe has a second inlet and a second outlet. The pusher screw is rotatably built into the conveying pipe and is used to push the material from the second inlet to the second outlet.

[0011] In one embodiment, the flue gas waste heat utilization component has two pusher screws, which are parallel to each other and spaced apart, and both pusher screws are built into the conveying pipe; The flue gas waste heat utilization component also includes a transmission structure, which connects the two pusher screws and drives the other pusher screw to rotate when one of the pusher screws rotates.

[0012] In one embodiment, there are multiple flue gas waste heat utilization components, which are arranged sequentially along the height direction, and the second discharge port of the conveying pipe of two adjacent flue gas waste heat utilization components along the height direction is connected to the second feed port.

[0013] In one embodiment, the first discharge port of the outer shell of the external waste heat utilization component is connected to the second inlet of the conveying pipe in the flue gas waste heat utilization component.

[0014] In one embodiment, the feeding screw includes a rotating shaft and helical blades. The rotating shaft is arranged along the axial direction of the conveying pipe and is rotatably connected to the conveying pipe. The helical blades are connected to the rotating shaft and are coaxially arranged with the rotating shaft. The outer edge of the helical blades has multiple notches. The notches are triangular and their size gradually increases in the direction away from the rotating shaft.

[0015] Secondly, the present invention also relates to a rotary kiln system, including the aforementioned waste heat utilization device outside the kiln and calcining kiln.

[0016] Compared with the prior art, the beneficial effects of the present invention include: when processing phosphogypsum material, the phosphogypsum material is introduced into the outer shell through the first feed port, and then enters the processing cavity formed between the outer shell and the kiln cylinder. The rotating kiln cylinder drives the pusher to rotate, and the pusher pushes the phosphogypsum material to move within the processing cavity, so that the phosphogypsum material moves from the first feed port of the outer shell to the first discharge port. The hot kiln cylinder surface exchanges heat with the phosphogypsum material through contact, transferring heat to the phosphogypsum material for dehydration and drying. Traditionally, the residual heat on the kiln cylinder surface is considered waste heat and is not effectively utilized. By placing the phosphogypsum material between the kiln cylinder and the outer shell, this originally wasted waste heat is actively recovered as a heat source for phosphogypsum modification, achieving dehydration and drying of phosphogypsum without the need for additional fuel. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the waste heat utilization device outside the kiln according to an embodiment of the present invention; Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle; Figure 3 This is a schematic diagram of the structure of the kiln head and flue gas waste heat utilization component in the kiln external waste heat utilization device according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the flue gas waste heat utilization component in the kiln external waste heat utilization device according to an embodiment of the present invention; Figure 5 yes Figure 4 A magnified view of a portion of point B in the middle; Figure 6 This is a schematic diagram of the structure of the flue gas waste heat utilization component in the kiln external waste heat utilization device according to an embodiment of the present invention; Figure 7 yes Figure 6 A magnified view of a portion of point C in the middle; Figure 8 This is a schematic diagram of the outer shell of the waste heat utilization device for kilns according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the waste heat utilization device for kilns according to an embodiment of the present invention after the outer shell is hidden; Figure 10 yes Figure 9 A magnified view of a portion of point D.

[0018] Explanation of reference numerals in the attached figures: External waste heat utilization component 1; outer shell 11; first feed inlet 11a; first discharge outlet 11b; pusher 12; pusher plate 121; Calcination kiln 2; kiln cylinder 21; kiln head 22; kiln tail 23; Flue gas waste heat utilization component 3; conveying pipe 31; second feed inlet 31a; second discharge outlet 31b; pusher screw 32; rotating shaft 321; screw blade 322; notch 322a; transmission structure 33; gear 331. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] To address the technical problem of requiring a large amount of additional fuel to process phosphogypsum, this invention provides a waste heat utilization device and rotary kiln system outside the kiln, which can calcine phosphogypsum to obtain gypsum and reduce fuel consumption.

[0021] It should be noted that the waste heat utilization device outside the kiln described in this invention is used for, but not limited to, the calcination of phosphogypsum. For ease of explanation, this invention will only use the application of the waste heat utilization device outside the kiln to the calcination of phosphogypsum as an example. The principle of the waste heat utilization device outside the kiln in other types of equipment is essentially the same as that in the calcination of phosphogypsum, and will not be described in detail here.

[0022] like Figure 1 As shown, the present invention provides a waste heat utilization device for kilns, including a waste heat utilization component 1. The waste heat utilization component 1 includes a shell 11 and a pusher 12. The shell 11 is configured to be fitted onto the kiln shell 21 of a calcining kiln 2, and a processing cavity is formed between the shell 11 and the kiln shell 21. The shell 11 has a first feed inlet 11a and a first discharge outlet 11b that communicate with the processing cavity. The pusher 12 is configured to be fixed to the outer wall of the kiln shell 21 and built into the processing cavity, for pushing the material from the first feed inlet 11a to the first discharge outlet 11b. The kiln shell 21 can be the kiln body of a calcining kiln 2 or a rotary kiln, or the cylinder body of other rotary heating equipment.

[0023] When processing phosphogypsum material, the phosphogypsum material is introduced into the outer shell 11 through the first feed port 11a. The phosphogypsum material then enters the processing chamber formed between the outer shell 11 and the kiln cylinder 21. The rotating kiln cylinder 21 drives the pusher 12 to rotate, and the pusher 12 pushes the phosphogypsum material to move within the processing chamber, moving the phosphogypsum material from the first feed port 11a to the first discharge port 11b of the outer shell 11. The hot surface of the kiln cylinder 21 exchanges heat with the phosphogypsum material through contact, transferring heat to the phosphogypsum material for dehydration and drying. Traditionally, the residual heat on the surface of the kiln cylinder 21 is considered waste heat and is not effectively utilized. By placing the phosphogypsum material between the kiln cylinder 21 and the outer shell 11, this originally wasted waste heat is actively recovered as a heat source for phosphogypsum modification, achieving dehydration and drying of phosphogypsum without the need for additional fuel.

[0024] To prevent dust from overflowing, in one embodiment, the waste heat utilization device outside the kiln also includes a negative pressure dust extraction device (not shown in the figure). The negative pressure dust extraction port of the negative pressure dust extraction device is connected to the feed end and the discharge end of the outer shell 11, and the connection is close to the first feed port 11a and the first discharge port 11b, respectively.

[0025] The negative pressure dust extraction device is used to extract dust from the processing chamber under negative pressure, preventing the dust formed by the dehydrated and calcined material from overflowing. The dust collected by the negative pressure dust extraction device can be used as material for cyclic calcination, and the collected dust can be recycled to reduce solid waste.

[0026] Among them, the negative pressure dust extraction device can be a combination of a negative pressure fan and a bag filter. The negative pressure fan provides negative pressure suction, which draws the extracted air into the bag filter. The bag filter filters the airflow and intercepts the dust in the airflow.

[0027] It should be understood that the pusher 12 can be a spiral strip, a spiral plate, etc., specifically, such as Figure 9 and Figure 10 As shown, in one embodiment, the pusher 12 includes a plurality of push plates 121, which are distributed at intervals along the circumference and axial direction of the kiln cylinder 21. The push plates 121 are spiral in shape and are all coaxially arranged with the kiln cylinder 21.

[0028] By setting the pusher 12 as multiple push plates 121, the multiple intermittent push plates 121 can generate a dispersed scraping and stirring effect on the phosphogypsum material in the processing cavity, which is conducive to the uniform mixing and heating of the phosphogypsum material and may reduce the adhesion or agglomeration of the phosphogypsum material.

[0029] like Figure 9 and Figure 10As shown, in one embodiment, the pusher plate 121 is bent toward the adjacent pusher plate 121 on the side away from the kiln cylinder 21, and the bending direction of the plurality of pusher plates 121 is the same.

[0030] Compared with traditional straight blades, the pusher plate 121 is straight near the kiln cylinder 21 and arc-shaped away from the kiln cylinder 21. When the kiln cylinder 21 rotates, it drives the pusher plate 121 to rotate. During the process of the rotating pusher plate 121 pushing the material, the material not only has a component that moves along the length of the pusher plate 121, but also a rotation component that rotates along the arc surface of the pusher plate 121. This allows the phosphogypsum material to achieve more thorough cross-mixing in the processing chamber, greatly improving the uniformity of temperature and composition in the chamber and avoiding local over-drying or over-wetting. The straight section can transmit the torque and material resistance generated by the rotation of the pusher plate 121 to the fixed point. It has good bending and torsional resistance and serves as the force base of the entire pusher plate 121, ensuring that it does not deform or get damaged when stirring high-viscosity phosphogypsum.

[0031] It should be understood that the outer shell 11 can be a cylindrical or square shell, specifically, such as Figure 8 As shown, in one embodiment, the bottom of the outer shell 11 is arc-shaped and configured to be coaxial with the kiln cylinder 21. The size of the outer shell 11 gradually increases from the bottom to the top. The cross-section of the outer shell 11 is V-shaped.

[0032] When the kiln cylinder 21 of the calcining kiln 2 rotates, the pusher 12 fixed to the outer wall of the kiln cylinder 21 rotates accordingly, pushing the phosphogypsum material from the first feed port 11a to the first discharge port 11b within the processing cavity formed by the outer shell 11 and the kiln cylinder 21. The bottom of the outer shell 11 is arc-shaped and coaxial with the kiln cylinder 21, maintaining a relatively uniform thickness of the material in the processing cavity, avoiding local thinning or accumulation, and ensuring a stable heat transfer process. The V-shaped structure uses gravity to allow the material to naturally gather towards the bottom center, increasing the contact density and time between the material and the wall of the kiln cylinder 21, thereby significantly improving the waste heat absorption efficiency. The inclined walls on both sides help the material flow towards the center under the action of the pusher 12, while reducing the adhesion or retention of material in the corners, reducing the risk of blockage, and making the conveying smoother.

[0033] like Figure 1 and Figure 2As shown, in one embodiment, there are multiple external waste heat utilization components 1, which are spaced apart along the axial direction of the kiln cylinder 21. The first feed inlet 11a and the first discharge outlet 11b of the outer shell 11 of the multiple external waste heat utilization components 1 are connected in series. The multiple external waste heat utilization components 1 can be arranged sequentially along the heating direction of the kiln cylinder 21, so that the phosphogypsum material can be heated sequentially to achieve waste heat recovery, dehydration, and drying of the phosphogypsum material. The high-temperature section can be used for deep dehydration of the phosphogypsum material, while the medium- and low-temperature sections can be used for preheating or slow drying of the phosphogypsum material. This allows the heat energy to match the process according to the temperature gradient, improving waste heat efficiency and reducing effective energy loss.

[0034] By connecting multiple external preheating components in series, the phosphogypsum material can pass through multiple external waste heat utilization components 1 in sequence, so that the phosphogypsum material is gradually and intermittently heated, and then dehydrated and dried in sequence.

[0035] like Figure 1 , 3 As shown in Figure 4, in one embodiment, there are multiple external waste heat utilization components 1. Multiple external waste heat utilization components 1 are distributed at intervals in the horizontal and vertical directions within the kiln head 22 and kiln tail 23. Multiple external waste heat utilization components 1 in the same column are connected in series from top to bottom in the vertical direction.

[0036] By setting up multiple external waste heat utilization components 1, and distributing these components 1 horizontally and vertically at intervals within the kiln head 22 and kiln tail, the heat from the flue gas and thermal radiation within the kiln head 22 and kiln tail 23 can be fully utilized, thus fully recovering and utilizing the waste heat.

[0037] In order to fully utilize the heat of the high-temperature flue gas in the kiln head 22 and kiln tail, therefore, as Figure 1 , 3 As shown in Figure 4, in one embodiment, the external waste heat utilization device further includes a flue gas waste heat utilization component 3. The flue gas waste heat utilization component 3 is disposed in the kiln head 22 and / or kiln tail 23 of the calcining kiln 2. The flue gas waste heat utilization component 3 includes a conveying pipe 31 and a pushing screw 32. The conveying pipe 31 has a second inlet 31a and a second outlet 31b. The pushing screw 32 is rotatably built into the conveying pipe 31 and is used to push the material from the second inlet 31a to the second outlet 31b. The conveying pipe 31 can be horizontally, vertically, or inclined.

[0038] The phosphogypsum material is fed into the conveying pipe 31, and the pusher screw 32 pushes the phosphogypsum material to move in the conveying pipe 31. High-temperature flue gas is formed in the kiln head 22 and kiln tail 23. The high-temperature flue gas passes through the conveying pipe 31 and heats the phosphogypsum material in the conveying pipe 31, and performs crystallization calcination on the phosphogypsum material.

[0039] It should be understood that the number of feeding screws 32 in the flue gas waste heat utilization component 3 can be one, two, or more, for example, Figure 4 , 5 As shown in Figure 6, in one embodiment, the flue gas waste heat utilization component 3 has two pusher screws 32, which are parallel to each other and spaced apart. Both pusher screws 32 are built into the conveying pipe 31. The flue gas waste heat utilization component 3 also includes a transmission structure 33, which connects the two pusher screws 32 and is used to drive the other pusher screw 32 to rotate when one pusher screw 32 rotates.

[0040] In this embodiment, the coordinated rotation of the two feeding spirals 32 creates a more complex material flow trajectory within the pipe, promoting the tumbling, shearing, and cross-mixing of the phosphogypsum material. This ensures full contact between the phosphogypsum and the hot flue gas and the conveying pipe 31, preventing localized overheating or agglomeration and improving the uniformity and efficiency of waste heat absorption. The double spiral structure covers a wider area at the bottom of the conveying pipe 31, eliminating blind spots that may occur with a single spiral. For easily agglomerated and highly moist phosphogypsum materials, the coordinated pushing of the double spirals effectively breaks up localized accumulations, preventing material from sticking to the walls or clogging the pipe. The transmission structure 33 links the two spirals; when one feeding spiral 32 rotates, it drives the other feeding spiral 32 to rotate synchronously, saving the need for an additional drive motor.

[0041] It should be understood that the conveying pipe 31 can have an elliptical or square cross-section. Specifically, for example... Figure 4 As shown, in one embodiment, the bottom of the conveying pipe 31 is an arc surface, and the top of the conveying pipe 31 is open.

[0042] During the high-temperature calcination process, phosphogypsum continuously generates water vapor. By opening the top of the conveying pipe 31, the steam can flow directly out from the opening, which can prevent the steam from accumulating in the conveying pipe 31 and causing the pressure to rise, thus hindering the movement of phosphogypsum material or the spraying of phosphogypsum material. During maintenance, the conveying pipe 31 can be directly maintained through the top opening.

[0043] like Figure 4 As shown, in one embodiment, there are multiple flue gas waste heat recovery components 3, which are arranged sequentially along the height direction. The second discharge port 31b and the second feed port 31a of the conveying pipes 31 of two adjacent flue gas waste heat recovery components 3 are connected. It should be understood that in order to enable the multiple waste heat recovery components 3 to be arranged side by side in the vertical direction, the arrangement directions of adjacent waste heat recovery components 3 are opposite, and the second discharge port 31b and the second feed port 31a of adjacent waste heat recovery components 3 can be connected by pipes.

[0044] In this embodiment, by setting up multiple flue gas waste heat utilization components 3 arranged in sequence along the vertical direction, forming a counter-current heat exchange path in series, the heat exchange time is extended, so that the phosphogypsum material is gradually heated and achieves crystallization calcination; the high-temperature flue gas at the bottom contacts the phosphogypsum material that is about to be discharged, and the low-temperature flue gas at the top contacts the phosphogypsum material that has just entered, so that a large average temperature difference is always maintained, so that heat is transferred efficiently, significantly reducing the final exhaust temperature of the flue gas and improving the waste heat recovery rate.

[0045] It should be understood that the external waste heat utilization component 1 and the flue gas waste heat utilization component 3 can be used individually or in combination. Specifically, in one embodiment, the first discharge port 11b of the outer shell 11 of the external waste heat utilization component 1 is connected to the second inlet port 31a of the conveying pipe 31 in the flue gas waste heat utilization component 3.

[0046] The phosphogypsum material is first gradually heated in contact with the residual heat outside the cylinder using component 1 to remove most of the free water; then it enters the flue gas component for rapid crystallization and calcination to completely remove residual moisture. This step-by-step treatment effectively prevents over-burning, crystal destruction, or surface hardening and crusting caused by rapid heating, ensuring the uniformity and stability of the final moisture content of the phosphogypsum.

[0047] It should be understood that the pusher screw 32 can be a spiral blade or multiple spiral plates, specifically, as shown in the example. Figure 5 and Figure 7 As shown, in one embodiment, the feeding screw 32 includes a rotating shaft 321 and a spiral blade 322. The rotating shaft 321 is arranged along the axial direction of the conveying pipe 31 and is rotatably connected to the conveying pipe 31. The spiral blade 322 is connected to the rotating shaft 321 and is coaxially arranged with the rotating shaft 321. The outer edge of the spiral blade 322 has multiple notches 322a, which are triangular in shape and gradually increase in size in the direction away from the rotating shaft 321. A gear 331 is fitted onto the rotating shaft 321.

[0048] By setting a rotating shaft 321, the rotating shaft 321 realizes the rotational connection between the pushing screw 32 and the conveying pipe 31. By setting a triangular notch 322a on the edge of the screw blade 322, the notch 322a disrupts the continuity of the screw blade 322, generating periodic disturbances when pushing materials, so that the gypsum slurry increases radial and circumferential mixing while moving axially, ensuring that the material is heated more evenly and avoiding local overheating or undercooking. The changes in flow velocity and flow direction generated when the material flows through the notch 322a form a local shear force, which helps to break up any early agglomerates that may form, preventing the material from sticking, bridging or blocking at high temperatures.

[0049] By setting the notch 322a into a triangle and gradually increasing its size in the direction away from the axis of rotation 321, the phosphogypsum material at the outer edge of the spiral blade 322 comes into contact with the high temperature first, resulting in the fastest crystallization and calcination. It is also prone to agglomeration. The larger notch 322a here provides a stronger ability to disperse and renew the material surface, making heat transfer more efficient. At the same time, the size of the notch 322a decreases in the direction closer to the axis of rotation 321. The smaller notch 322a here can generate moderate and gentle stirring, which is conducive to the stable and uniform transfer of heat from the high temperature zone at the outer edge to the inside. This avoids the internal material from being underheated due to excessive renewal, thereby ensuring that the material is calcined and crystallized uniformly from the outside to the inside.

[0050] The transmission structure 33 can be a gear meshing structure, or a sprocket and chain structure, etc. Specifically, for example... Figure 6 and Figure 7 As shown, in one embodiment, the spiral blades 322 of the two pusher screws 32 in the flue gas waste heat utilization component 3 are interlocked, and the transmission structure 33 includes two meshing gears 331, which are respectively sleeved on the rotating shafts 321 of the two pusher screws 32.

[0051] By interlocking the spiral blades 322 in the feeding screw 32, the phosphogypsum material in the conveying pipe 31 can be fully stirred and dispersed. By setting the transmission structure 33 as interlocking gears 331, the spiral blades 322 in the two feeding screws 32 rotate synchronously, avoiding collision and damage to the interlocking spiral blades 322 during rotation.

[0052] In order to drive multiple feeding screws 32 to rotate, it should be understood that multiple screws 32 can be driven to rotate by a single motor combined with multiple chains, and multiple feeding screws 32 can be driven to rotate by multiple gears. Alternatively, each flue gas waste heat utilization component 3 can be equipped with a motor and transmission gear.

[0053] like Figure 1 As shown, in a second aspect, the present invention also relates to a rotary kiln system, including the aforementioned waste heat utilization device outside the kiln and calcining kiln 2.

[0054] In one embodiment, the outer shell 11 is fitted onto the kiln cylinder 21 of the calcining kiln 2. Multiple outer shells 11 can be fixed to the ground by brackets or fixed to other equipment in the warehouse. The push plate 121 in the pusher 12 can be fixedly welded to the outer wall of the kiln cylinder 21, or it can be fixed to the outer wall of the kiln cylinder 21 by bolts and screws. The conveying pipe 31 can be directly fixed to the inner wall of the kiln head 22 or the kiln tail 23, or it can be indirectly fixed to the inner wall of the kiln head 22 or the kiln tail 23 by brackets.

[0055] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A device for utilizing waste heat outside a kiln, characterized in that, include: An external waste heat utilization component includes a shell and a pusher. The shell is configured to be fitted onto the kiln shell of a calcining kiln. A processing cavity is formed between the shell and the kiln shell. The shell has a first feed inlet and a first discharge outlet that communicate with the processing cavity. The pusher is configured to be fixed to the outer wall of the kiln shell and built into the processing cavity, and is used to push the material from the first feed inlet to the first discharge outlet.

2. The waste heat utilization device outside the kiln according to claim 1, characterized in that, The pushing component includes multiple push plates, which are distributed at intervals along the circumference and axial direction of the kiln cylinder. The push plates are spiral-shaped and are all coaxially arranged with the kiln cylinder.

3. The waste heat utilization device outside the kiln according to claim 1, characterized in that, The bottom of the outer shell is arc-shaped and configured to be coaxial with the kiln cylinder. The size of the outer shell gradually increases from the bottom to the top.

4. The waste heat utilization device outside the kiln according to claim 1, characterized in that, There are multiple external waste heat utilization components, which are spaced apart along the axial direction of the kiln cylinder, and the first feed inlet and first discharge outlet of the outer shell of the multiple external waste heat utilization components are connected in series from end to end.

5. The waste heat utilization device outside the kiln according to claim 1, characterized in that, It also includes a flue gas waste heat utilization component, which is configured in the kiln head and / or kiln tail of the calcining kiln. The flue gas waste heat utilization component includes a conveying pipe and a pusher screw. The conveying pipe has a second inlet and a second outlet. The pusher screw is rotatably built into the conveying pipe and is used to push the material from the second inlet to the second outlet.

6. The waste heat utilization device outside the kiln according to claim 5, characterized in that, The flue gas waste heat utilization component has two feeding screws, which are parallel to each other and spaced apart. Both feeding screws are built into the conveying pipe. The flue gas waste heat utilization component also includes a transmission structure, which connects the two pusher screws and drives the other pusher screw to rotate when one of the pusher screws rotates.

7. The waste heat utilization device outside the kiln according to claim 5, characterized in that, The number of flue gas waste heat utilization components is multiple, and the multiple flue gas waste heat utilization components are arranged sequentially along the height direction. The second discharge port of the conveying pipe of two adjacent flue gas waste heat utilization components along the height direction is connected to the second feed port.

8. The waste heat utilization device outside the kiln according to claim 5, characterized in that, The first discharge port of the outer shell of the external waste heat utilization component is connected to the second inlet of the conveying pipe in the flue gas waste heat utilization component.

9. The waste heat utilization device outside the kiln according to claim 5, characterized in that, The feeding screw includes a rotating shaft and spiral blades. The rotating shaft is arranged along the axial direction of the conveying pipe and is rotatably connected to the conveying pipe. The spiral blades are connected to the rotating shaft and are coaxially arranged with the rotating shaft. The outer edge of the spiral blades has multiple notches. The notches are triangular and their size gradually increases in the direction away from the rotating shaft.

10. A rotary kiln system, characterized in that, It includes the waste heat utilization device and calcining kiln as described in any one of claims 1 and 9.

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