Ceramsite proppant rotary kiln with waste heat recovery function and use method

Abstract

The application discloses a ceramsite propping agent rotary kiln with waste heat recovery function and a use method, relates to the technical field of rotary kilns, and comprises a preheating kiln, a firing kiln, a cooling kiln, a fixed connection ring, a combustion pipe, two first transmission units and two second transmission units. The preheating kiln, the firing kiln, the fixed connection ring and the cooling kiln are sequentially connected, one end of the preheating kiln is connected with a feeding end, one end of the cooling kiln is connected with a discharging end, one end of the combustion pipe penetrates through the fixed connection ring from the outside, and the other end of the combustion pipe is located in the firing kiln. A waste heat exchange assembly is arranged between the preheating kiln and the cooling kiln, the two first transmission units are arranged between the preheating kiln and the firing kiln, the two second transmission units are arranged between the firing kiln and the cooling kiln, and the combustion pipe penetrates into the firing kiln through the fixed connection ring. Compared with the design that the combustion pipe is inserted into the kiln from the end of the rotary kiln in the general case, the time of the flame passing through the combustion pipe can be reduced.

Description

Technical Field

[0001] This invention relates to the field of rotary kiln technology, specifically to a ceramic aggregate proppant rotary kiln with waste heat recovery function and its application method. Background Technology

[0002] Ceramsite proppant, also known as petroleum fracturing proppant or ceramsite sand, is a ceramic particle material specifically used in oil and gas extraction. It is mainly used in hydraulic fracturing operations to support rock formation fractures. During the fracturing process of deep oil and gas wells, after the high-pressure fluid fractures the rock formation, ceramsite proppant enters the fracture with the fracturing fluid. Through its high strength and stability, it supports the fracture and prevents closure, forming a permanent flow channel. Compared with natural quartz sand, ceramsite proppant can increase oil and gas production by 30%–50% and extend the service life of oil wells, forming oil and gas channels with high conductivity. The rotary kiln for ceramsite proppant is a special industrial kiln designed for firing this material.

[0003] The kiln body is inclined at an angle to the horizontal. The material is mixed, heated and moved forward while rotating. The pulverized coal injection pipe provides heat. The refractory lining inside the kiln can withstand high temperatures. The existing kiln is a unidirectional system without circulation function. Therefore, the temperature recovery and utilization rate of the rotary kiln is low and the energy consumption is high. Summary of the Invention

[0004] The purpose of this invention is to provide a rotary kiln with waste heat recovery function for ceramsite proppant and a method of using it, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a rotary kiln for ceramsite proppant with waste heat recovery function, comprising a preheating kiln, a firing kiln, a cooling kiln, a fixed connecting ring, a combustion tube, two first transmission units and two second transmission units. The preheating kiln, firing kiln, fixed connecting ring and cooling kiln are connected sequentially. One end of the preheating kiln is connected to the feed end, and one end of the cooling kiln is connected to the discharge end. One end of the combustion tube passes through the fixed connecting ring from the outside, and the other end of the combustion tube is located inside the firing kiln. A waste heat exchange assembly is provided between the preheating kiln and the cooling kiln. Two first drive units are set between the preheating kiln and the firing kiln, and two second drive units are set between the firing kiln and the cooling kiln. Fixed connecting rings are fixedly installed. The combustion tube passes through the fixed connecting rings into the interior of the firing kiln. Compared with the general design where the combustion tube extends into the kiln from the end of the rotary kiln, the length of the combustion tube entering the kiln is shortened, reducing the time the flame passes through the combustion tube and making the combustion tube more durable. The firing kiln and the cooling kiln can be directly connected. The fired ceramsite support agent loses less temperature during the movement process, which is more conducive to subsequent heat exchange.

[0006] Furthermore, the height of the preheating kiln is higher than that of the cooling kiln. The preheating kiln, firing kiln, cooling kiln, and fixed connecting ring are inclined. The outer rings at both ends of the preheating kiln, firing kiln, and cooling kiln are provided with teeth. The end faces of the preheating kiln, firing kiln, cooling kiln, and fixed connecting ring are provided with annular grooves. A sealing ring is provided between every two closely spaced annular grooves. The sealing ring is used to seal the connection between the preheating kiln, firing kiln, cooling kiln, and fixed connecting ring.

[0007] Furthermore, a first transmission ring is provided on the outer ring at the connection between the preheating kiln and the firing kiln. The inner ring of the first transmission ring has an inner tooth groove, which engages with the teeth of the preheating kiln and the firing kiln. Two first transmission units are symmetrically installed. Each first transmission unit includes a servo motor and a conical friction wheel. The conical friction wheel is mounted on the motor shaft of the servo motor. The conical friction wheel of the first transmission unit is in contact with the first transmission ring.

[0008] Furthermore, a second transmission ring and a third transmission ring are respectively provided on the outer rings of the firing kiln and the cooling kiln on the side close to each other. The inner rings of the second transmission ring and the third transmission ring are also provided with internal grooves. The internal grooves of the second transmission ring and the third transmission ring respectively cooperate with the teeth of the firing kiln and the cooling kiln. Several retainers are evenly distributed in a ring on the fixed connecting ring. Each retainer is slidably connected to the second transmission ring and the third transmission ring. Each second transmission unit includes a servo motor and two conical friction wheels. The two conical friction wheels are connected to the servo motor and are in contact with the second transmission ring and the third transmission ring respectively. The servo motor drives the conical friction wheels to rotate. The conical friction wheels drive the preheating kiln and the firing kiln to rotate through the first transmission ring. Similarly, the conical friction wheels of the second transmission unit drive the firing kiln and the cooling kiln to rotate. The ceramsite proppant flows slowly to the lower side in the rotating rotary kiln and tumbles in the rotary kiln to make the ceramsite proppant heat evenly.

[0009] Furthermore, the preheating kiln is equipped with several first heat-conducting pipes, each of which penetrates the preheating kiln. The several first heat-conducting pipes are arranged in a spiral shape and are sealed to the preheating kiln. The waste heat exchange assembly includes a preheating jacket, which is fitted on the outside of the preheating kiln and is rotatably sealed to the preheating kiln. When high-temperature and high-pressure steam passes through the preheating jacket, the steam temperature is directly applied to the interior of the preheating kiln through the spirally arranged first heat-conducting pipes. This allows the ceramsite proppant to fully exchange heat with the steam through the first heat-conducting pipes, achieving the effect of preheating the ceramsite proppant. The preheated ceramsite proppant shortens the heating time during firing in the firing kiln, reducing fuel consumption. This not only saves energy but also reduces emissions, achieving energy conservation and environmental protection.

[0010] Furthermore, the cooling kiln is equipped with several second heat-conducting pipes, each of which penetrates the cooling kiln. The pipes are arranged in a spiral pattern and are sealed to the kiln. Each second heat-conducting pipe has retaining rings at both ends and contains steel balls with a diameter smaller than the inner diameter of the pipe. The waste heat exchange assembly includes a heat exchange jacket fitted around the outside of the cooling kiln, and the jacket is rotatably and sealed to the kiln. The ceramsite proppant, after firing, has a high residual temperature. The second heat-conducting pipes, which are arranged in a spiral pattern in the cooling kiln, come into direct contact with the ceramsite proppant, raising the temperature in the second heat-conducting pipes. When water is introduced into the second heat-conducting pipes, the water is rapidly heated and vaporized, forming high-temperature steam. The water pressure can push the steel balls into the second heat-conducting pipes. The steel balls prevent the steam from flowing downwards and force it out of the second heat-conducting pipes. The auxiliary steam quickly enters the heat exchange jacket from the second heat-conducting pipes, causing the temperature of the ceramsite proppant to drop, thus achieving a cooling effect.

[0011] Furthermore, the waste heat exchange assembly also includes a water pump, a steam delivery pipe, a water inlet pipe, and a drain pipe. The water inlet pipe is connected to the inside of the heat exchange jacket, the drain pipe is connected to the bottom of the preheating jacket, the steam delivery pipe is connected between the heat exchange jacket and the preheating jacket, and the water pump is connected to the water inlet pipe. The water pump delivers water into the heat exchange jacket through the water inlet pipe, and the vaporized high-temperature and high-pressure water vapor is delivered into the preheating jacket through the steam delivery pipe. The water vapor that is cooled and liquefied in the preheating jacket is discharged from the drain pipe.

[0012] A method for using a rotary kiln with waste heat recovery function for proppant ceramsite includes the following steps;

[0013] S1: Start the combustion tube to ignite the interior of the kiln;

[0014] S2: Start the first and second transmission units to drive the rotary kiln to rotate;

[0015] S3: The ceramsite proppant is conveyed into the preheating kiln through the feed end, and the ceramsite proppant slowly moves towards the discharge end of the cooling kiln in the rotary kiln.

[0016] S4: Start the water pump to supply water to the heat exchange jacket. The temperature of the cooling kiln heats the water in the heat exchange jacket. High-temperature steam enters the preheating kiln through the steam delivery pipe. The high temperature of the steam preheats the ceramsite support in the preheating kiln.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. The combustion tube is inserted into the kiln through a fixed connecting ring. Compared with the general design where the lower combustion tube extends into the kiln from the end of the rotary kiln, the length of the combustion tube entering the kiln is shortened, reducing the time the flame passes through the combustion tube and making the combustion tube more durable. The kiln and the cooling kiln can be directly connected. The ceramsite support agent loses less heat during the movement process, which is more conducive to subsequent heat exchange.

[0019] 2. The temperature of the steam is directly applied to the interior of the preheating kiln through the first heat-conducting pipes arranged in a spiral pattern. This allows the ceramsite proppant to fully exchange heat with the steam through the first heat-conducting pipes, thus achieving the effect of preheating the ceramsite proppant. The preheated ceramsite proppant shortens the heating time during firing in the firing kiln, reducing fuel consumption. This not only saves energy but also reduces emissions, achieving energy conservation and environmental protection. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure 1 ;

[0021] Figure 2 This is a schematic diagram of the overall structure of the present invention. Figure 2 ;

[0022] Figure 3 This is a partial structural diagram of the present invention. Figure 1 ;

[0023] Figure 4 This is a partial structural diagram of the present invention. Figure 2 ;

[0024] Figure 5 This is a partial structural diagram of the present invention. Figure 3 ;

[0025] Figure 6 This is a schematic diagram of the internal structure of the preheating kiln of the present invention;

[0026] Figure 7 This is a schematic diagram of the internal structure of the cooling kiln of the present invention.

[0027] In the diagram: 1. Preheating kiln; 2. Firing kiln; 3. Cooling kiln; 4. Fixed connecting ring; 5. Combustion tube; 6. Cage; 7. First transmission ring; 8. Second transmission ring; 9. Third transmission ring; 10. First transmission unit; 11. Second transmission unit; 12. Servo motor; 13. Conical friction wheel; 14. Heat exchange jacket; 15. Preheating jacket; 16. Steam delivery pipe; 17. Water inlet pipe; 18. Drain pipe; 19. First heat conduction pipe; 20. Second heat conduction pipe; 21. Retaining ring; 22. Steel ball; 23. Sealing ring. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example: Figures 1-7 As shown, this invention provides a technical solution: a rotary kiln for ceramsite proppant with waste heat recovery function, comprising a preheating kiln 1, a firing kiln 2, a cooling kiln 3, a fixed connecting ring 4, a combustion tube 5, two first drive units 10, and two second drive units 11. The preheating kiln 1, firing kiln 2, fixed connecting ring 4, and cooling kiln 3 are connected sequentially. One end of the preheating kiln 1 is connected to the feed end, and one end of the cooling kiln 3 is connected to the discharge end. One end of the combustion tube 5 passes through the fixed connecting ring 4 from the outside, and one end of the combustion tube 5 is located inside the firing kiln 2. A waste heat exchange assembly is provided between the preheating kiln 1 and the cooling kiln 3. The two first drive units 10 are located between the preheating kiln 1 and the firing kiln 2, and the two second drive units 11 are located between the firing kiln 2 and the cooling kiln 3. The height of the preheating kiln 1 is higher than the height of the cooling kiln 3. The fixed connecting ring 4 is inclined. The outer rings at both ends of the preheating kiln 1, the firing kiln 2, and the cooling kiln 3 are provided with teeth. The end faces of the preheating kiln 1, the firing kiln 2, the cooling kiln 3, and the fixed connecting ring 4 are provided with annular grooves. A sealing ring 23 is provided between every two annular grooves that are close to each other. The sealing ring 23 is used to seal the connection between the preheating kiln 1, the firing kiln 2, the cooling kiln 3, and the fixed connecting ring 4. The fixed connecting ring 4 is fixedly set. The combustion tube 5 passes through the fixed connecting ring 4 into the interior of the firing kiln 2. Compared with the general design where the combustion tube 5 extends into the kiln from the end of the rotary kiln, the length of the combustion tube 5 entering the kiln is shortened, reducing the time the flame passes through the combustion tube 5, making the combustion tube 5 more durable. The firing kiln 2 and the cooling kiln 3 can be directly connected. The fired ceramsite support agent loses less heat during the movement process, which is more conducive to subsequent heat exchange.

[0030] A first transmission ring 7 is provided on the outer ring at the connection between the preheating kiln 1 and the firing kiln 2. The inner ring of the first transmission ring 7 has an internal groove that meshes with the teeth of the preheating kiln 1 and the firing kiln 2. Two first transmission units 10 are symmetrically installed. Each first transmission unit 10 includes a servo motor 12 and a conical friction wheel 13. The conical friction wheel 13 is mounted on the motor shaft of the servo motor 12. The conical friction wheel 13 of the first transmission unit 10 contacts the first transmission ring 7. A second transmission ring 8 and a third transmission ring 9 are respectively provided on the outer ring of the firing kiln 2 and the cooling kiln 3 on the side that are close to each other. The inner rings of the second transmission ring 8 and the third transmission ring 9 also have internal grooves that mesh with the teeth of the firing kiln 2 and the cooling kiln 3, respectively, to fix them in place. Several retainers 6 are evenly distributed in a ring on the connecting ring 4. Each retainer 6 is slidably connected to the second transmission ring 8 and the third transmission ring 9. Each second transmission unit 11 includes a servo motor 12 and two conical friction wheels 13. The two conical friction wheels 13 are connected to the servo motor 12 and are in contact with the second transmission ring 8 and the third transmission ring 9, respectively. The servo motor 12 drives the conical friction wheels 13 to rotate. The conical friction wheels 13 drive the preheating kiln 1 and the firing kiln 2 to rotate through the first transmission ring 7. Similarly, the conical friction wheels 13 of the second transmission unit 11 drive the firing kiln 2 and the cooling kiln 3 to rotate. The ceramsite proppant flows slowly to the lower side in the rotating rotary kiln and tumbles in the rotary kiln to make the ceramsite proppant heat evenly.

[0031] The preheating kiln 1 is equipped with several first heat conduction pipes 19, each of which penetrates the preheating kiln 1. The several first heat conduction pipes 19 are arranged in a spiral shape and are sealed to the preheating kiln 1. The waste heat exchange assembly includes a preheating jacket 15, which is fitted onto the outside of the preheating kiln 1 and is rotatably sealed to the preheating kiln 1. The cooling kiln 3 is equipped with several second heat conduction pipes 20, each of which penetrates the cooling kiln 3. The several second heat conduction pipes 20 are arranged in a spiral shape and are sealed to the cooling kiln 3. Each second heat conduction pipe 20 has a [missing information - likely a device or structure] at both ends. There is a retaining ring 21. Each second heat conduction pipe 20 has a steel ball 22 inside. The diameter of the steel ball 22 is smaller than the inner diameter of the second heat conduction pipe 20. The waste heat exchange assembly includes a heat exchange jacket 14, which is sleeved on the outside of the cooling kiln 3. The heat exchange jacket 14 is rotatably sealed to the cooling kiln 3. The waste heat exchange assembly also includes a water pump (not shown in the figure), a steam conveying pipe 16, a water inlet pipe 17, and a drain pipe 18. The water inlet pipe 17 is connected to the inside of the heat exchange jacket 14, and the drain pipe 18 is connected to the bottom of the preheating jacket 15. The steam conveying pipe 16 is connected between the heat exchange jacket 14 and the preheating jacket 15, and the water pump is connected to the water inlet pipe 17.

[0032] A water pump delivers water into the heat exchange jacket 14 via the inlet pipe 17. The vaporized, high-temperature, high-pressure steam is then sent into the preheating jacket 15 via the steam delivery pipe 16. In the preheating jacket 15, the cooled and liquefied steam is discharged through the drain pipe 18. The sintered ceramic proppant remains at a high residual temperature. The second heat-conducting pipe 20, spirally arranged in the cooling kiln 3, directly contacts the ceramic proppant, raising its temperature. When water is introduced into the second heat-conducting pipe 20, it is rapidly heated and vaporized, forming high-temperature steam. The water pressure can push open the steel ball 22 and enter the second heat-conducting pipe 20. The steel ball 22 prevents the steam from flowing downwards in reverse, thus preventing the steam from flowing backwards into the second heat-conducting pipe 20. The auxiliary steam is extruded from the second heat-conducting pipe 20 and quickly enters the heat exchange jacket 14 from the second heat-conducting pipe 20. The temperature of the ceramsite proppant drops, achieving a cooling effect. When the high-temperature and high-pressure steam passes through the preheating jacket 15, the temperature of the steam passes through the first heat-conducting pipe 19, which is spirally arranged in the preheating kiln 1. The temperature of the steam directly acts on the interior of the preheating kiln 1, so that the ceramsite proppant can fully exchange heat with the steam through the first heat-conducting pipe 19, achieving the effect of preheating the ceramsite proppant. When the preheated ceramsite proppant is fired in the firing kiln 2, the heating time is shortened and the fuel consumption is reduced. This not only saves energy but also reduces the emission of combustion products, achieving the effect of energy saving and environmental protection.

[0033] The working principle of this invention is as follows: The sealing ring 23 is used to seal the connection between the preheating kiln 1, the firing kiln 2, the cooling kiln 3, and the fixed connecting ring 4. The fixed connecting ring 4 is fixedly set. The combustion tube 5 passes through the fixed connecting ring 4 into the interior of the firing kiln 2. Compared with the general design where the combustion tube 5 extends into the kiln from the end of the rotary kiln, the length of the pipe through which the combustion tube 5 enters the kiln is shortened, reducing the time the flame passes through the combustion tube 5, making the combustion tube 5 more durable. The firing kiln 2 and the cooling kiln 3 can be directly connected. The fired ceramsite support agent loses less heat during the movement process, which is more conducive to subsequent heat exchange.

[0034] Servo motor 12 drives conical friction wheel 13 to rotate. Conical friction wheel 13 drives preheating kiln 1 and firing kiln 2 to rotate through first transmission ring 7. Similarly, conical friction wheel 13 of second transmission unit 11 drives firing kiln 2 and cooling kiln 3 to rotate. The ceramsite proppant flows slowly to the lower side in the rotating rotary kiln and tumbles in the rotary kiln so that the ceramsite proppant is heated evenly.

[0035] A water pump delivers water into the heat exchange jacket 14 via the inlet pipe 17. The vaporized, high-temperature, high-pressure steam is then sent into the preheating jacket 15 via the steam delivery pipe 16. In the preheating jacket 15, the cooled and liquefied steam is discharged through the drain pipe 18. The sintered ceramic proppant remains at a high residual temperature. The second heat-conducting pipe 20, spirally arranged in the cooling kiln 3, directly contacts the ceramic proppant, raising its temperature. When water is introduced into the second heat-conducting pipe 20, it is rapidly heated and vaporized, forming high-temperature steam. The water pressure can push open the steel ball 22 and enter the second heat-conducting pipe 20. The steel ball 22 prevents the steam from flowing downwards in reverse, thus preventing the steam from flowing backwards into the second heat-conducting pipe 20. The auxiliary steam is extruded from the second heat-conducting pipe 20 and quickly enters the heat exchange jacket 14 from the second heat-conducting pipe 20. The temperature of the ceramsite proppant drops, achieving a cooling effect. When the high-temperature and high-pressure steam passes through the preheating jacket 15, the temperature of the steam passes through the first heat-conducting pipe 19, which is spirally arranged in the preheating kiln 1. The temperature of the steam directly acts on the interior of the preheating kiln 1, so that the ceramsite proppant can fully exchange heat with the steam through the first heat-conducting pipe 19, achieving the effect of preheating the ceramsite proppant. When the preheated ceramsite proppant is fired in the firing kiln 2, the heating time is shortened and the fuel consumption is reduced. This not only saves energy but also reduces the emission of combustion products, achieving the effect of energy saving and environmental protection.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A rotary kiln for ceramsite proppant with waste heat recovery function, characterized in that: The system includes a preheating kiln (1), a firing kiln (2), a cooling kiln (3), a fixed connecting ring (4), a combustion tube (5), two first transmission units (10) and two second transmission units (11). The preheating kiln (1), firing kiln (2), fixed connecting ring (4) and cooling kiln (3) are connected in sequence. One end of the preheating kiln (1) is connected to the feed end, and one end of the cooling kiln (3) is connected to the discharge end. One end of the combustion tube (5) passes through the fixed connecting ring (4) from the outside, and one end of the combustion tube (5) is located inside the firing kiln (2). A waste heat exchange component is provided between the preheating kiln (1) and the cooling kiln (3). The two first transmission units (10) are located between the preheating kiln (1) and the firing kiln (2), and the two second transmission units (11) are located between the firing kiln (2) and the cooling kiln (3). The preheating kiln (1) is provided with several first heat conduction pipes (19), each of which penetrates the preheating kiln (1). The several first heat conduction pipes (19) are arranged in a spiral shape. The first heat conduction pipes (19) are sealed to the preheating kiln (1). The waste heat exchange assembly includes a preheating jacket (15). The preheating jacket (15) is sleeved on the outside of the preheating kiln (1). The preheating jacket (15) is rotatably sealed to the preheating kiln (1). The cooling kiln (3) is provided with several second heat conduction pipes (20), each of which penetrates the cooling kiln (3). The several second heat conduction pipes (20) are arranged in a spiral shape. The second heat conduction pipes (20) are sealed to the cooling kiln (3). Each second heat conduction pipe (20) has a retaining ring (21) at both ends. Each second heat conduction pipe (20) has a steel ball (22) inside. The diameter of the steel ball (22) is smaller than the inner diameter of the second heat conduction pipe (20). The waste heat exchange assembly includes a heat exchange jacket (14). The heat exchange jacket (14) is sleeved on the outside of the cooling kiln (3). The heat exchange jacket (14) is rotatably sealed to the cooling kiln (3). The waste heat exchange assembly also includes a water pump, a steam delivery pipe (16), a water inlet pipe (17), and a drain pipe (18). The water inlet pipe (17) is connected to the inside of the heat exchange jacket (14), the drain pipe (18) is connected to the bottom of the preheating jacket (15), the steam delivery pipe (16) is connected between the heat exchange jacket (14) and the preheating jacket (15), and the water pump is connected to the water inlet pipe (17).

2. The rotary kiln with waste heat recovery function for ceramic aggregate proppant according to claim 1, characterized in that: The height of the preheating kiln (1) is higher than that of the cooling kiln (3). The preheating kiln (1), the firing kiln (2), the cooling kiln (3) and the fixed connecting ring (4) are inclined. The outer rings at both ends of the preheating kiln (1), the firing kiln (2) and the cooling kiln (3) are provided with teeth. The end faces of the preheating kiln (1), the firing kiln (2), the cooling kiln (3) and the fixed connecting ring (4) are provided with ring grooves. A sealing ring (23) is provided between every two ring grooves that are close to each other.

3. A rotary kiln with waste heat recovery function for ceramsite proppant according to claim 2, characterized in that: A first transmission ring (7) is provided on the outer ring at the connection between the preheating kiln (1) and the firing kiln (2). The inner ring of the first transmission ring (7) is provided with an inner tooth groove, which is engaged with the teeth of the preheating kiln (1) and the firing kiln (2). Two first transmission units (10) are symmetrically installed. Each first transmission unit (10) includes a servo motor (12) and a conical friction wheel (13). The conical friction wheel (13) is installed on the motor shaft of the servo motor (12). The conical friction wheel (13) of the first transmission unit (10) is in contact with the first transmission ring (7).

4. A rotary kiln with waste heat recovery function for ceramsite proppant according to claim 3, characterized in that: The firing kiln (2) and the cooling kiln (3) are respectively provided with a second transmission ring (8) and a third transmission ring (9) on the outer ring of the side close to each other. The inner ring of the second transmission ring (8) and the third transmission ring (9) is also provided with an inner tooth groove. The inner tooth groove of the second transmission ring (8) and the third transmission ring (9) respectively cooperates with the teeth of the firing kiln (2) and the cooling kiln (3). Several retainers (6) are evenly distributed in a ring on the fixed connecting ring (4). Each retainer (6) is slidably connected to the second transmission ring (8) and the third transmission ring (9). Each second transmission unit (11) includes a servo motor (12) and two conical friction wheels (13). The two conical friction wheels (13) are connected to the servo motor (12). The two conical friction wheels (13) are in contact with the second transmission ring (8) and the third transmission ring (9) respectively.

5. A method for using a rotary kiln with waste heat recovery function for ceramsite proppant as described in any one of claims 1-4, characterized in that: Includes the following steps; S1: Start the combustion tube (5) to burn inside the firing kiln (2); S2: Start the first transmission unit (10) and the second transmission unit (11) to drive the rotary kiln to rotate; S3: The ceramsite proppant is conveyed into the preheating kiln (1) through the feed end, and the ceramsite proppant slowly moves towards the discharge end of the cooling kiln (3) in the rotary kiln; S4: Start the water pump to supply water to the heat exchange jacket (14), and the temperature of the cooling kiln (3) heats the water in the heat exchange jacket (14). High-temperature steam enters the preheating kiln (1) through the steam delivery pipe (16), and the high temperature of the steam preheats the ceramsite support in the preheating kiln (1).

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