Method for external heat recovery of a rotary kiln

Abstract

This invention relates to the field of waste heat recovery technology, and in particular to a method for recovering external heat from a rotary kiln. The method includes a base, on which a rotary kiln body is mounted. A large gear ring is fixed to the outer wall of the rotary kiln body. After the rotary kiln is started, the operator activates an oil pump. The oil pump continuously draws oil from the oil tank into the interior of the heat exchange hood at a certain speed. The oil in the heat exchange hood fills the entire interior from bottom to top. On one hand, the oil inside the heat exchange hood lubricates the large gear ring and gears, ensuring stable meshing between them. On the other hand, using oil as a heat exchange medium allows heat from the large gear ring and the outer wall of the rotary kiln body to be absorbed into the oil, reducing the temperature of the large gear ring and the outer wall of the rotary kiln body. This helps prevent the large gear ring from developing excessive tooth clearance due to high-temperature expansion.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a method for recovering external heat from a rotary kiln. Background Technology

[0002] A rotary kiln is a type of rotary kiln, generally consisting of a dust collection chamber at the feed end, a slowly rotating kiln body, a kiln head carriage at the discharge end, a hot flue chamber, and a cooler. The kiln body is at a 3°-5° angle to the horizontal plane, and is driven by a motor through a reducer to rotate a large gear. Fuel and primary air enter the kiln through burners located on the kiln head carriage and extending into the kiln. Secondary air, preheated by the material in the cooler, enters the kiln through the hot flue chamber. Combustion products pass through the kiln body, dust collection chamber, and dust collector, and are discharged through a chimney by an exhaust fan. The raw material to be calcined enters the kiln through the feed pipe at the kiln tail, and is propelled forward by the rotation of the inclined kiln body, where it encounters the combustion products coming from the kiln head. After undergoing drying, preheating, and calcination processes, it falls from the kiln head into the cooler. The cooler cylinder also rotates at an incline, so the material and airflow move in opposite directions.

[0003] Existing technologies disclose some invention patents for waste heat recovery. Chinese invention patent application number 200810059507.9 discloses a heat dissipation recovery and utilization device for a cement rotary kiln shell, which includes several heat exchange covers arranged in sections on the rotary kiln shell. The outer surface of the heat exchange cover is provided with a heat insulation layer, and a sealing device is provided between the two ends of the heat exchange cover and the rotary kiln shell.

[0004] Rotary kilns are widely used in metallurgy, chemical industry, building refractory materials, environmental sanitation and other industries. A typical rotary kiln consists of a cylinder, support device, support device with thrust rollers, transmission device, movable kiln head, kiln tail sealing device, and pulverized coal injection pipe device. The kiln body is inclined to the horizontal and supported by the roller device. Due to the high temperature during operation, the temperature of the outer wall of the rotary kiln rises. The large gear ring, which is in direct contact with the outer wall, also experiences a temperature increase due to heat conduction. This high temperature increases the tooth clearance of the large gear ring, affecting the meshing between the large gear ring and the gears. Simultaneously, the large gear ring dissipates a large amount of heat into the outside air, representing a recoverable waste heat resource, thus resulting in resource waste. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies, such as the high temperature of the rotary kiln during operation leading to an increase in the temperature of the outer wall of the rotary kiln, and the large gear ring in direct contact with the outer wall of the rotary kiln also experiencing a temperature increase due to heat conduction. The high temperature increases the tooth tip clearance of the large gear ring, thus affecting the meshing between the large gear ring and the gear. At the same time, the large gear ring dissipates a large amount of heat into the outside air, which is a recoverable waste heat resource, resulting in resource waste. Therefore, this invention proposes a method for external heat recovery from rotary kilns.

[0006] In a first aspect, the present invention provides a method for external heat recovery of a rotary kiln, comprising a base, a rotary kiln body mounted on the top of the base, and a large toothed ring fixed on the outer wall of the rotary kiln body. The recovery method includes the following steps:

[0007] Step 1: Install the heat exchanger at the designated location on the rotary kiln body;

[0008] Step 2: Introduce heat exchange medium into the heat exchange device, and the heat emitted from the rotary kiln body is absorbed into the heat exchange medium;

[0009] Step 3: The heat exchange medium after heat absorption is introduced into an external heating and power generation device to recover and utilize the external heat of the rotary kiln.

[0010] The heat exchange device mentioned in steps one to three includes:

[0011] A heat exchange hood is fixed to the top of the base, and the heat exchange hood is slidably and sealingly connected to the outer wall of the rotary kiln body;

[0012] A support mechanism is installed on top of the base, and the support mechanism is used to support the rotary kiln body;

[0013] A power unit is used to drive the rotary kiln body to rotate;

[0014] A conveying mechanism is used to feed the heat exchange medium into the interior of the heat exchange shroud, and then send the heat-absorbing heat exchange medium out of the heat exchange shroud.

[0015] In further implementation, the supporting mechanism includes:

[0016] Four mounting bases are fixedly installed on the top of the base, and each of the four mounting bases is rotatably connected to a support roller. Two support rollers on the same side form a group.

[0017] Both tires are fixed to the outer wall of the rotary kiln body and respectively abut against the two sets of support rollers.

[0018] In a further implementation process, multiple baffles are fixed in a circumferential array on the inner wall of the heat exchange shroud.

[0019] In a further implementation process, arc-shaped plates are symmetrically fixed on the outer wall of the heat exchange shroud, and cavities are opened inside the two arc-shaped plates. The ends of all the baffles away from the large gear ring pass through the side walls of the corresponding heat exchange shroud and the arc-shaped plates, and the ends of all the baffles away from the large gear ring extend into the interior of the two cavities.

[0020] A water pump is fixed to the top of the base. The outlet of the water pump is fixedly connected to the two cavities through a branched outlet pipe. A pipe is fixedly connected to the top of each cavity, and the other end of the pipe is connected to an external heating device.

[0021] In a further implementation process, baffles are symmetrically rotatably connected to the inner wall of the heat exchange hood, and multiple openings are provided through the side wall of the baffles. All the openings are arranged in a circumferential array, and the two baffles divide the internal space of the heat exchange hood into three parts.

[0022] In a further implementation process, multiple round rods are fixed in a circumferential array on both side walls of the large gear ring. One end of each round rod passes through the corresponding baffle, and the round rods on the same side are slidably connected to the baffle.

[0023] In a further implementation process, the heat exchange medium fills the entire interior of the heat exchange shroud from bottom to top.

[0024] In a further implementation process, a collection box is fixed to the top of the heat exchange hood, a filter screen is installed inside the collection box, the heat exchange hood and the collection box are connected by a connecting pipe, and a discharge pipe is fixedly connected to one side of the collection box.

[0025] In a further implementation process, an electromagnet is fixed inside the collection box.

[0026] In further implementation, the interior of the rotary kiln body is divided into a preheating zone, a transition zone, a firing zone, and a cooling zone, and the discharge pipe penetrates the side walls of the two mounting seats located in the cooling zone.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention, through the setting of a heat exchange hood, allows the operator to start the oil pump after the rotary kiln is started. The oil pump continuously draws oil from the oil tank into the interior of the heat exchange hood at a certain speed. The oil in the heat exchange hood fills the entire interior of the hood from bottom to top. On the one hand, the oil inside the heat exchange hood can lubricate the large gear ring and gears, making the meshing of the large gear ring and gears stable and reducing friction between them. This reduces frictional heat generation and wear on the large gear ring and gears, which is beneficial for their long-term use. On the other hand, using oil as a heat exchange medium can absorb the heat from the large gear ring and the outer wall of the rotary kiln body into the oil, reducing the temperature of the large gear ring and the outer wall of the rotary kiln body. This helps prevent the large gear ring from developing increased tooth clearance due to high-temperature expansion.

[0029] 2. By using heat sinks, this invention can transfer the heat from the oil in the heat exchange hood to the water. On the one hand, the water absorbs some of the heat from the oil, thus lowering the oil temperature and increasing the temperature difference between the oil and the large gear ring. This improves the oil's heat absorption efficiency for waste heat, which is beneficial for improving heat dissipation from the large gear ring and waste heat recovery. On the other hand, the cavity reduces heat loss and increases the recovered heat. Meanwhile, the heated water is sent to an external heating device to convert the heat in the water into warm air for the use of staff.

[0030] 3. By using baffles, this invention addresses the issue that the rotary kiln body experiences normal up-and-down movement during operation. This movement causes the large gear ring to move laterally. As the large gear ring moves within the heat exchange hood, it promotes the flow of oil inside the hood. The baffles divide the heat exchange hood into three sections. Driven by the large gear ring, the oil flows back and forth within the three cavities of the heat exchange hood, increasing its fluidity. Heat in the oil near the large gear ring can be transferred to adjacent oil sections more quickly, while the oil further away from the large gear ring has a lower temperature. Once the oil begins to flow, it is easier for the oil further away from the large gear ring to contact it, thus facilitating the absorption of heat from the large gear ring. Attached Figure Description

[0031] Figure 1 This is a flowchart of the waste heat recovery method of the present invention.

[0032] Figure 2 This is a schematic diagram of the first overall structure of the present invention.

[0033] Figure 3 This is a schematic diagram of the second overall structure of the present invention.

[0034] Figure 4 This is a cross-sectional view of the rotary kiln body of the present invention.

[0035] Figure 5 For the present invention Figure 4 Enlarged view of the structure at point A in the middle.

[0036] Figure 6 This is a cross-sectional view of the heat exchange shroud of the present invention.

[0037] Figure 7 For the present invention Figure 6 Enlarged view of the structure at point B in the middle.

[0038] In the diagram: 1. Base; 2. Rotary kiln body; 3. Large gear ring; 4. Heat exchange hood; 5. Mounting seat; 6. Support roller; 7. Tire; 8. Baffle; 9. Arc plate; 10. Cavity; 11. Water pump; 12. Baffle; 13. Opening; 14. Round rod; 15. Collection box; 16. Filter screen; 17. Electromagnet; 18. Drive motor; 19. Gear; 20. Oil pump. Detailed Implementation

[0039] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0040] like Figures 1 to 7 The illustrated method for external heat recovery from a rotary kiln includes a base 1, a rotary kiln body 2 mounted on top of the base 1, and a large gear ring 3 fixed to the outer wall of the rotary kiln body 2. The recovery method includes the following steps:

[0041] Step 1: Install the heat exchange device at the designated position on the rotary kiln body 2;

[0042] Step 2: Introduce heat exchange medium into the heat exchange device, and the heat emitted from the rotary kiln body 2 is absorbed into the heat exchange medium;

[0043] Step 3: The heat exchange medium after heat absorption is introduced into an external heating and power generation device to recover and utilize the external heat of the rotary kiln.

[0044] The heat exchange devices in steps one through three include:

[0045] The heat exchange cover 4 is fixed on the top of the base 1. The heat exchange cover 4 is sleeved on the outer ring of the rotary kiln body 2. The heat exchange cover 4 is slidably and sealed to the outer wall of the rotary kiln body 2.

[0046] A support mechanism is installed on top of the base 1 and is used to support the rotary kiln body 2.

[0047] The power unit is used to drive the rotary kiln body 2 to rotate;

[0048] The conveying mechanism is used to feed the heat exchange medium into the interior of the heat exchange shroud 4, and then send the heat exchange medium after heat absorption out of the heat exchange shroud 4.

[0049] In the specific implementation process, the power components include:

[0050] The drive motor 18 is fixedly installed on the top of the base 1. The output shaft of the drive motor 18 passes through the side wall of the heat exchange shroud 4 and extends into the interior of the heat exchange shroud 4. The output shaft of the drive motor 18 is fixed with a gear 19, which meshes with the large gear ring 3.

[0051] The heat exchange medium is oil;

[0052] The conveying mechanism includes: an oil pump 20, which is installed on the top of the base 1. The oil inlet of the oil pump 20 is connected to the oil tank placed in the working space, and the oil outlet of the oil pump 20 is fixedly connected to the inside of the heat exchange hood 4 through an oil pipe.

[0053] The heat exchange shroud 4 is slidably sealed to the outer wall of the rotary kiln body 2. The interaction between the two sliding parts is ensured by a certain amount of friction and sealing force, so that the oil in the heat exchange shroud 4 will not flow out from the gaps caused by the movement during the normal movement of the rotary kiln body 2.

[0054] It should be noted that:

[0055] Rotary kilns are complex thermal equipment. Under high temperature and heavy load operation, they are affected by various factors such as mechanical force, thermal deformation, and chemical corrosion. In addition, their tilt, uneven temperature and different expansion rates cause local cross-sectional deformation of the cylinder. In particular, the gap between the inner diameter of the tire 7 and the cylinder pad has a great influence on the cross-sectional deformation of the cylinder.

[0056] The rotary kiln's cylinder is made of rolled steel plates, lined with refractory lining, and inclined at a specified angle to the horizontal line. It is supported by a support mechanism. During normal operation, the drive motor 18 drives the gear 19 to rotate. The large gear ring 3 rotates through the meshing of the gear 19, thereby driving the rotary kiln to rotate.

[0057] The material enters the kiln from the tail and is calcined. Due to the tilting and slow rotation of the cylinder, the material rolls along the circumference and moves along the axis to continue the decomposition and calcination process. Finally, the clinker is cooled by the cooler through the kiln head hood.

[0058] Specifically, due to the high temperature during the operation of the rotary kiln, the temperature of the outer wall of the rotary kiln rises. The large gear ring 3, which is in direct contact with the outer wall of the rotary kiln, also experiences a temperature increase due to heat conduction. The high temperature increases the tooth tip clearance of the large gear ring 3, thereby affecting the meshing between the large gear ring 3 and the gear 19. At the same time, the large gear ring 3 dissipates a large amount of heat to the outside air, which is a recoverable waste heat resource, resulting in a waste of resources.

[0059] This embodiment of the present invention can solve the above problems. The specific implementation method is as follows: First, after the rotary kiln is started, the operator starts the oil pump 20. The oil pump 20 continuously draws oil from the oil tank in the work area at a certain speed and sends it into the interior of the heat exchange hood 4. The oil in the heat exchange hood 4 fills the entire interior of the heat exchange hood 4 from bottom to top. On the one hand, the oil inside the heat exchange hood 4 can lubricate the large gear ring 3 and the gear 19, so that the meshing of the large gear ring 3 and the gear 19 is stable, and the friction between the large gear ring 3 and the gear 19 is reduced. This can reduce frictional heat generation and reduce the wear of the large gear ring 3 and the gear 19, which is beneficial to the long-term use of the large gear ring 3 and the gear 19.

[0060] On the other hand, using oil as a heat exchange medium can absorb the heat on the outer wall of the large gear ring 3 and the rotary kiln body 2 into the oil, thereby reducing the temperature of the outer wall of the large gear ring 3 and the rotary kiln body 2. Oil has a fast heat conduction speed, which can quickly absorb the heat on the outer wall of the large gear ring 3 and the rotary kiln body 2 into the oil, which helps to prevent the large gear ring 3 from having an increased tooth gap due to high temperature expansion.

[0061] Meanwhile, the oil with a higher temperature after heat exchange is discharged from the top outlet of heat exchange hood 4 to power the heating equipment or power generation in the plant, so as to recover and utilize the waste heat resources. It can also be converted into reusable thermal energy or other energy forms through conduction, conversion and utilization.

[0062] It should be noted that waste heat refers to the sensible and latent heat in energy-consuming equipment of industrial enterprises that has not been rationally utilized in the original design due to limitations caused by historical, technological, and conceptual factors. It includes waste heat from high-temperature exhaust gases, cooling media, waste steam and wastewater, high-temperature products and slag, chemical reactions, combustible waste gases and liquids, and waste materials. According to surveys, the total waste heat resources of various industries account for approximately 17% to 67% of their total fuel consumption, and about 60% of these resources are recyclable.

[0063] In the further implementation process, the supporting institutions include:

[0064] Four mounting bases 5 are fixedly installed on the top of the base 1. Each of the four mounting bases 5 is rotatably connected to a support roller 6. Two support rollers 6 on the same side form a group.

[0065] Both tires 7 are fixed on the outer wall of the rotary kiln body 2 and respectively abut against the two sets of support rollers 6;

[0066] Specifically, the function of the tire 7 is to transfer the entire weight of the cylinder to the support roller 6 and enable the cylinder to rotate smoothly on the support roller 6. Therefore, the tire 7 must have sufficient strength and durability. At the same time, the tire 7 is also a part that strengthens the radial stiffness of the cylinder, so it should ensure sufficient stiffness.

[0067] The support roller 6 is one of the main components of the rotary kiln. It bears the weight of the entire rotary kiln and enables the cylinder and rolling ring to rotate smoothly on the support roller 6.

[0068] During the kiln shutdown, the strength of the tire 7 needs to be tested. If there are any problems, it needs to be replaced in time to avoid affecting the later production.

[0069] It should be noted that the rotary kiln body 2, which is mounted on the support roller 6, moves normally under the drive of the power unit. There are three main reasons for this: First, the weight of the kiln body and the friction between the support roller 6 and the tire 7 will generate axial force. At the same time, the tire 7 and the axis of the support roller 6 are not parallel, generating additional axial force. Under the action of force, the axial position of the rotary kiln body 2 is not fixed and needs to move along the axial direction.

[0070] Secondly, the rotary kiln is installed in a cold state and operated in a hot state. Due to the principle of thermal expansion and contraction, the length of the cylinder will change accordingly. When its surface temperature reaches about 100~250℃, there is a large amount of axial elongation in the cylinder. In order to ensure the normal operation of the equipment, it is necessary to ensure that the width of the support roller 6 exceeds the width of the tire 7, so as to avoid problems such as insufficient bearing surface or roller ring detachment. Based on this, the cylinder needs to be able to reciprocate along the axial direction.

[0071] Thirdly, in the rotary kiln, the width of the support roller 6, the tire 7, the large gear ring 3, the gear 19, or the seals of the kiln head and kiln tail cannot allow the cylinder to move freely. In order to ensure the normal and stable operation of the equipment, the axial movement distance of the cylinder needs to be controlled within a certain range.

[0072] In further implementation, multiple baffles 8 are fixed in a circumferential array on the inner wall of the heat exchange shroud 4;

[0073] Specifically, after the entire internal space of the heat exchange shroud 4 is filled with oil, more oil is added to the interior of the heat exchange shroud 4. Most of the oil will move directly from the bottom to the top along the gaps in the side walls of the heat exchange shroud 4. The oil in the gaps of the large gear ring 3 has poor flow. With the help of the baffles 8, when the oil moves from bottom to top in the heat exchange shroud 4, the flow trajectory of the oil is blocked by the baffles 8. The flowing oil impacts the side wall of the baffles 8 and then refracts along the side wall of the baffles 8 towards the gaps of the large gear ring 3, so that the oil flows into the gaps of the large gear ring 3. This increases the flow contact between the oil and the surface of the large gear ring 3, thereby increasing the heat absorption of the large gear ring 3 by the oil. On the one hand, this is conducive to the rapid temperature reduction of the large gear ring 3, and on the other hand, it is conducive to the full absorption of heat by the oil, thus increasing the efficiency of waste heat recovery.

[0074] In the further implementation process, arc-shaped plates 9 are symmetrically fixed on the outer wall of the heat exchange shroud 4. The two arc-shaped plates 9 have cavities 10 inside. The ends of all the baffles 8 away from the large gear ring 3 pass through the side walls of the corresponding heat exchange shroud 4 and arc-shaped plates 9 respectively. The ends of all the baffles 8 away from the large gear ring 3 extend into the interior of the two cavities 10 respectively.

[0075] A water pump 11 is fixed on the top of the base 1. The outlet of the water pump 11 is fixedly connected to two cavities 10 through a branched outlet pipe. A pipe is fixedly connected to the top of the cavity 10, and the other end of the pipe is connected to an external heating device.

[0076] In the specific implementation process, by connecting the pipeline to the external heating device, it is easy to convert the heat in the water into warm air for the use of the factory staff, thereby recovering and utilizing the waste heat.

[0077] Baffle 8 is specifically a heat sink;

[0078] Specifically, the water pump 11 draws low-temperature water from the water tank and sends it through water pipes into the two cavities 10. The heat exchange fins transfer the heat from the oil in the heat exchange hood 4 to the water. On one hand, the water absorbs some of the heat from the oil, lowering its temperature and increasing the temperature difference between the oil and the large gear ring 3. This improves the oil's heat absorption efficiency and facilitates heat dissipation from the large gear ring 3 and waste heat recovery. On the other hand, the cavities 10 reduce heat loss and increase the recovered heat. Meanwhile, the heated water is sent to the external heating device, where the heat in the water is converted into warm air for the staff.

[0079] In a further implementation process, baffles 12 are symmetrically rotatably connected to the inner wall of the heat exchange hood 4. Multiple openings 13 are opened through the side wall of the baffles 12. All the openings 13 are arranged in a circumferential array. The two baffles 12 divide the internal space of the heat exchange hood 4 into three parts.

[0080] Specifically, during operation, the rotary kiln body 2 will experience normal up-and-down movement. When the rotary kiln body 2 moves, it drives the large gear ring 3 to move laterally. After the large gear ring 3 moves inside the heat exchange shroud 4, it can push the oil inside the heat exchange shroud 4 to flow. The baffle 12 divides the inside of the heat exchange shroud 4 into three parts. Under the push of the large gear ring 3, the oil flows back and forth in the three cavities 10 inside the heat exchange shroud 4, which increases the fluidity of the oil. The heat in the oil close to the large gear ring 3 can be transferred to the adjacent oil more quickly. At the same time, the oil far away from the large gear ring 3 has a lower temperature. After the oil starts to flow, the oil far away from the large gear ring 3 is more likely to come into contact with the large gear ring 3, which is conducive to the absorption of heat from the large gear ring 3 by the oil.

[0081] It should be noted that during heat conduction, the rate of heat transfer depends on the interaction between molecules and the efficiency of energy transfer. When oil flows, the probability of collisions between molecules increases, and the rate of energy transfer also increases, thus accelerating the transfer of heat.

[0082] In a further implementation process, multiple round rods 14 are fixed in a circumferential array on both side walls of the large gear ring 3. One end of the round rod 14 passes through the corresponding baffle 12, and the round rod 14 on the same side is slidably connected to the baffle 12.

[0083] Specifically, through the provided round rod 14, as the drive motor 18 drives the gear 19 to rotate, and the gear 19 drives the large gear ring 3 to rotate, the large gear ring 3 drives the round rod 14 to rotate synchronously, and the round rod 14 drives the baffle 12 to rotate synchronously. Thus, the baffle 12 and the large gear ring 3 rotate synchronously, so that the opening 13 on the baffle 12 is always aligned with the tooth gap of the large gear ring 3. Therefore, the oil flowing out from the opening 13 of the baffle 12 can directly flow into the tooth gap of the large gear ring 3. On the one hand, it is conducive to the oil flowing and contacting the surface of the large gear ring 3, thereby improving the heat absorption rate of the oil. On the other hand, it can prevent the large gear ring 3 from blocking the opening 13 on the baffle 12, which is conducive to the circulation of oil inside the heat exchange shroud 4.

[0084] In the further implementation process, the heat exchange medium fills the entire interior of the heat exchange shroud 4 from bottom to top;

[0085] In the specific implementation process, the heat exchange medium is oil;

[0086] Specifically, while the oil absorbs heat and cools the large gear ring 3 inside the heat exchange shroud 4, it can also flush the side wall of the large gear ring 3, which helps to wash away the iron filings generated by rust on the large gear ring 3. At the same time, after long-term operation, the meshing part of the gear 19 and the large gear ring 3 will also wear and generate iron filings. By filling the entire interior of the heat exchange shroud 4 with oil from bottom to top, the oil has a certain viscosity, so the flow of the oil can carry the iron filings out of the interior of the heat exchange shroud 4, preventing the iron filings from affecting the meshing of the gear 19 and the large gear ring 3.

[0087] In a further implementation process, a collection box 15 is fixed to the top of the heat exchange hood 4, and a filter screen 16 is installed inside the collection box 15. The heat exchange hood 4 and the collection box 15 are connected by a connecting pipe, and a discharge pipe is fixedly connected to one side of the collection box 15.

[0088] Specifically, through the provided collection box 15, the hot oil discharged from the heat exchange hood 4 enters the interior of the collection box 15 through the connecting pipe, and then passes through the provided filter screen 16. The hot oil can directly pass through the screen holes of the filter screen 16 and enter the bottom of the collection box 15, and then be discharged from the outlet at the bottom of the collection box 15. The iron filings carried away by the hot oil will remain on the filter screen 16, which helps to prevent the iron filings from affecting the subsequent treatment of the hot oil. The discharged hot oil can be used for power generation or heating equipment to make full use of waste heat and save energy.

[0089] In further implementation, an electromagnet 17 is fixed inside the collection box 15;

[0090] Specifically, after the rotary kiln is stopped, the operator energizes the electromagnet 17 to make it magnetic, which attracts the iron filings on the filter screen 16. Then, the sealed door on the top of the collection box 15 is opened to remove the electromagnet 17, which facilitates the collection of iron filings.

[0091] In further implementation, the interior of the rotary kiln body 2 is divided into a drying zone, a preheating zone, a transition zone, a firing zone, and a cooling zone, and the discharge pipe passes through the side walls of the two mounting seats 5 located in the cooling zone;

[0092] Specifically, in order to ensure a stable transmission connection between the support roller 6 and the belt 7, lubricating oil needs to be added inside the mounting base 5 to reduce the friction between the support roller 6 and the belt 7. Since the temperature of the cooling belt is low, the lubricating oil inside the mounting base 5 has low activity at low temperatures and is not easy to coat the outer surface of the support roller 6, which is not conducive to the lubrication of the support roller 6. By passing the discharge pipe through the side wall of the mounting base 5, the hot oil flowing inside the discharge pipe can transfer heat to the lubricating oil, so that the lubricating oil melts and becomes liquid, which is beneficial to the lubrication of the support roller 6.

[0093] It should be noted that:

[0094] Drying zone: Its main function in production is to dry the materials and evaporate the moisture they contain, so that the quality of the clinker will not be affected by excessive moisture during calcination.

[0095] Preheating zone: Its main function in production is to preheat the material so that it reaches the required temperature before entering the kiln, thereby accelerating the decomposition rate of the material during calcination and shortening the calcination time.

[0096] Burning zone: Its main function in production is to fully heat the materials, thereby causing a chemical reaction and producing clinker;

[0097] The transition zone plays a crucial role in production by allowing unreacted materials to undergo a full reaction, ensuring that the resulting clinker does not contain any raw materials.

[0098] Cooling zone: Its main function in production is to cool the produced high-temperature clinker, thereby reducing its temperature to a specified value, which facilitates the preservation of the clinker.

[0099] Working principle of this invention:

[0100] Because the rotary kiln operates at a high temperature, the temperature of the outer wall of the rotary kiln also rises. The large gear ring 3, which is in direct contact with the outer wall of the rotary kiln, will also rise in temperature due to heat conduction. The high temperature increases the tooth tip clearance of the large gear ring 3, thereby affecting the meshing between the large gear ring 3 and the gear 19. At the same time, the large gear ring 3 will dissipate a large amount of heat to the outside air, which is a recoverable waste heat resource, resulting in a waste of resources.

[0101] This embodiment of the present invention can solve the above problems. The specific implementation method is as follows: First, after the rotary kiln is started, the operator starts the oil pump 20. The oil pump 20 continuously draws oil from the oil tank in the work area at a certain speed and sends it into the interior of the heat exchange hood 4. The oil in the heat exchange hood 4 fills the entire interior of the heat exchange hood 4 from bottom to top. On the one hand, the oil inside the heat exchange hood 4 can lubricate the large gear ring 3 and the gear 19, so that the meshing of the large gear ring 3 and the gear 19 is stable, and the friction between the large gear ring 3 and the gear 19 is reduced. This can reduce frictional heat generation and reduce the wear of the large gear ring 3 and the gear 19, which is beneficial to the long-term use of the large gear ring 3 and the gear 19.

[0102] On the other hand, using oil as a heat exchange medium can absorb the heat on the outer wall of the large gear ring 3 and the rotary kiln body 2 into the oil, thereby reducing the temperature of the outer wall of the large gear ring 3 and the rotary kiln body 2. Oil has a fast heat conduction speed, which can quickly absorb the heat on the outer wall of the large gear ring 3 and the rotary kiln body 2 into the oil, which helps to prevent the large gear ring 3 from having an increased tooth gap due to high temperature expansion.

[0103] Meanwhile, the oil with a higher temperature after heat exchange is discharged from the top outlet of heat exchange hood 4 to power the heating equipment or power generation in the plant, so as to recover and utilize the waste heat resources. It can also be converted into reusable thermal energy or other energy forms through conduction, conversion and utilization.

[0104] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for external heat recovery of a rotary kiln, comprising a base (1), wherein a rotary kiln body (2) is mounted on the top of the base (1), and a large gear ring (3) is fixed on the outer wall of the rotary kiln body (2), characterized in that, The recycling method includes the following steps: Step 1: Install the heat exchange device at the designated position on the rotary kiln body (2); Step 2: The heat exchange medium is introduced into the heat exchange device, and the heat emitted from the rotary kiln body (2) is absorbed into the heat exchange medium; Step 3: The heat exchange medium after heat absorption is introduced into an external heating and power generation device to recover and utilize the external heat of the rotary kiln. The heat exchange device mentioned in steps one to three includes: A heat exchange hood (4) is fixed to the top of the base (1), and the heat exchange hood (4) is slidably and sealed to the outer wall of the rotary kiln body (2). A support mechanism is installed on top of the base (1) and is used to support the rotary kiln body (2); A power assembly is used to drive the rotary kiln body (2) to rotate; The conveying mechanism is used to send the heat exchange medium into the interior of the heat exchange shroud (4) and then send the heat exchange medium after heat absorption out of the heat exchange shroud (4). Multiple baffles (8) are fixed in a circumferential array on the inner wall of the heat exchange shroud (4). The heat exchange shroud (4) is symmetrically fixed with arc-shaped plates (9). The two arc-shaped plates (9) are provided with cavities (10). The ends of all the baffles (8) away from the large gear ring (3) pass through the side walls of the corresponding heat exchange shroud (4) and the arc-shaped plates (9). The ends of all the baffles (8) away from the large gear ring (3) extend into the interior of the two cavities (10). A water pump (11) is fixed on the top of the base (1). The outlet of the water pump (11) is fixedly connected to the two cavities (10) through a branched outlet pipe. A pipe is fixedly connected to the top of the cavity (10). The other end of the pipe is connected to an external heating device.

2. The method for external heat recovery of a rotary kiln according to claim 1, characterized in that, The supporting structure includes: Four mounting bases (5) are fixedly installed on the top of the base (1), and the top of each of the four mounting bases (5) is rotatably connected to a support roller (6). Two support rollers (6) on the same side form a group. The two tires (7) are fixed on the outer wall of the rotary kiln body (2) and respectively abut against the two sets of support rollers (6).

3. The method for external heat recovery of a rotary kiln according to claim 1, characterized in that, The heat exchange shroud (4) has baffles (12) symmetrically rotatably connected to its inner wall. Multiple openings (13) are provided through the side wall of the baffles (12). All the openings (13) are arranged in a circumferential array. The two baffles (12) divide the internal space of the heat exchange shroud (4) into three parts.

4. The method for external heat recovery of a rotary kiln according to claim 3, characterized in that, Multiple round rods (14) are fixed in a circumferential array on both side walls of the large gear ring (3). One end of each round rod (14) passes through the corresponding baffle (12), and the round rods (14) on the same side are slidably connected to the baffle (12).

5. The method for external heat recovery of a rotary kiln according to claim 1, characterized in that, The heat exchange medium fills the entire interior of the heat exchange shroud (4) from bottom to top.

6. The method for external heat recovery of a rotary kiln according to claim 2, characterized in that, A collection box (15) is fixed on the top of the heat exchange cover (4). A filter screen (16) is installed inside the collection box (15). The heat exchange cover (4) and the collection box (15) are connected by a connecting pipe. A discharge pipe is fixedly connected to one side of the collection box (15).

7. A method for external heat recovery in a rotary kiln according to claim 6, characterized in that, An electromagnet (17) is fixed inside the collection box (15).

8. The method for external heat recovery of a rotary kiln according to claim 7, characterized in that, The interior of the rotary kiln body (2) is divided into a preheating zone, a transition zone, a firing zone and a cooling zone, and the discharge pipe passes through the side walls of the two mounting seats (5) located in the cooling zone.

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