Energy-saving and environment-friendly tunnel kiln for sintering coal gangue bricks and sintering process thereof

Abstract

This invention discloses an energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks and its sintering process. The kiln includes a kiln body and a slide rail installed within it. Along its length, the kiln body sequentially includes a preheating zone, a firing zone, and a cooling zone. Kiln cars are mounted on the slide rails, and each kiln car is equipped with a support block and a support perforated plate. The firing zone sequentially includes a heating zone, a sintering zone, and a homogenizing zone. The top and sides of the sintering zone and preheating zone have interconnected airflow channels. These channels are divided into several independent inverted U-shaped gas distribution channels by partitions. The gas distribution channels in the front and rear halves of the sintering zone are connected by return air channels. Air inlet chambers are provided in the kiln side walls on both sides of the cooling zone. The sintering process includes brick blank loading, brick blank preheating, brick blank sintering, brick blank cooling, and brick blank unloading. In summary, this invention has the advantages of high thermal energy utilization, good brick blank heating effect, uniform temperature throughout, and energy saving and environmental protection.

Description

Technical Field

[0001] This invention belongs to the technical field of tunnel kilns for coal gangue brick sintering, specifically relating to an energy-saving and environmentally friendly tunnel kiln for coal gangue brick sintering and its sintering process. Background Technology

[0002] Coal gangue sintered bricks are primarily composed of coal gangue, a solid waste generated during coal mining and washing. Its main components are Al₂O₃ and SiO₂, along with varying amounts of Fe₂O₃, CaO, MgO, Na₂O, K₂O, P₂O₅, SO₃, and trace rare elements such as gallium, vanadium, titanium, and cobalt. The production cost of coal gangue sintered bricks is lower than that of ordinary clay bricks. They possess high strength, excellent thermal insulation, and align with my country's policies on building energy conservation and wall material reform. Besides saving energy and land, they also offer significant emission reduction benefits, achieving full utilization of waste, reducing environmental pollution, and improving the thermal insulation performance of buildings. The production process of coal gangue involves loading coal gangue into a hopper and conveying it to the raw material processing plant via a belt conveyor. After crushing and screening, the gangue is processed into qualified materials, then stirred, water is added, and the material is sent to an aging chamber for aging. The aged material is then stirred again and formed into brick blanks using a brick-making machine. After drying, the brick blanks are sent to a tunnel kiln for sintering into finished bricks. A tunnel kiln is typically a long, straight tunnel with fixed walls and an arched roof on both sides and top. Kiln cars run on tracks at the bottom. The combustion equipment is located on both sides of the middle section of the tunnel kiln, forming a fixed high-temperature firing zone, which also includes a preheating zone and a cooling zone.

[0003] Existing tunnel kilns often suffer from the following problems during the sintering of brick blanks: First, the outlet temperature of the tunnel kiln is relatively high, resulting in the emission of most of the heat energy, which wastes energy and heat and causes environmental pollution. Second, the firing zone and preheating zone of the tunnel kiln have large internal temperature differences and uneven heating, affecting heat utilization and the firing effect of the brick blanks. Therefore, it is an objective need to develop an energy-saving and environmentally friendly tunnel kiln and its sintering process for coal gangue brick sintering with high heat utilization, good brick blank heating effect, and uniform internal and external temperature. Summary of the Invention

[0004] In order to solve the problems existing in the background technology, the purpose of this invention is to provide an energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks with high thermal energy utilization, good brick heating effect, and uniform temperature at the top and bottom, as well as its sintering process.

[0005] The energy-saving and environmentally friendly tunnel kiln for coal gangue brick sintering of the present invention includes a kiln body and a slide rail installed inside the kiln body. The kiln body, along its length, includes a preheating zone, a firing zone, and a cooling zone. A kiln car is installed on the slide rail, and an insulation layer and a refractory layer are sequentially installed on the kiln car. A support perforated plate is installed on the refractory layer, and several support blocks are arranged in an array at intervals between the support perforated plate and the refractory layer. The firing zone includes a heating zone, a sintering zone, and a soaking zone. The top and sides of the sintering zone and the preheating zone are provided with interconnected airflow channels. These airflow channels are divided into several independent inverted U-shaped gas distribution channels by partitions. The top of the kiln body is provided with an upper... Air vents are provided on both sides of the kiln body, which are connected to each air distribution channel. The air jet direction of the air jet is towards the support block. The frontmost air distribution channel and the rearmost air distribution channel in the sintering zone are connected, as are the second frontmost air distribution channel and the second rearmost air distribution channel, and so on. The air channels in the first half of the sintering zone and the air distribution channels in the second half are connected by return air channels. Air inlet chambers are provided in the kiln body sidewalls on both sides of the cooling zone. The air inlet chambers are connected to the inside of the kiln body through cold air inlets. The cold air inlet at the bottom faces the support block. An exhaust chamber is provided at the top of the cooling zone. The top of the front end of the preheating zone is connected to a waste heat utilization device and a waste gas treatment device in sequence through an exhaust pipe.

[0006] Furthermore, a bottom-blowing air chamber is provided in the kiln body at the bottom of the cooling zone, and the top of the bottom-blowing air chamber is connected to the inside of the kiln body through a top-blowing hole.

[0007] Furthermore, side blowing holes connected to the gas distribution channels are provided on both sides of the sintering zone and the preheating zone, with the side blowing holes on each gas distribution channel arranged at intervals.

[0008] Furthermore, a baffle is installed on the top of the kiln body below each air distribution channel, and the baffle is located on the side of the upper air hole near the kiln head.

[0009] Furthermore, filter screens are installed in the airflow channels on both sides of the sintering zone and the preheating zone, with the filter screens closely attached to the side wall of the airflow channel facing the inside of the kiln.

[0010] Furthermore, ash removal ports are provided at the bottom of the airflow channels on both sides of the sintering zone and the preheating zone.

[0011] The sintering process of the energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to the present invention includes the following steps: ① Brick blanks are loaded into the kiln: The brick blanks are placed on the support plate of the kiln car, the kiln door is opened, the kiln car carries the brick blanks into the preheating zone, and the kiln door is closed. ② Brick preheating: The high-temperature gas generated by the firing zone flows towards the preheating zone and enters the preheating zone to heat and dry the bricks, thus completing the preheating of the bricks. During the preheating process, the high-temperature gas rises and enters the gas distribution channel through the upper air hole. It is then ejected from the jet holes on both sides of the kiln body and injected into the space where the support block is located. Then it is ejected upward from the support plate, forming an upward airflow in the kiln body. At the same time, it flows a distance towards the kiln head and enters the next gas distribution channel, and so on. Finally, it is sent to the waste heat utilization device and the waste gas treatment device through the exhaust pipe to complete the waste heat utilization and waste gas treatment before being discharged. ③ Sintering of brick blanks: The brick blanks are driven into the sintering zone by the kiln car. After preheating, the brick blanks gradually enter the heating zone, sintering zone and homogenization zone of the sintering zone. When entering the heating zone, the brick blanks soften and begin to sinter. When entering the sintering zone, the sintering of the brick blanks is completed. During the sintering process, the high-temperature gas rises and enters the gas distribution channel through the upper gas hole. Then it is ejected from the jet holes on both sides of the kiln body and sprayed into the space where the support block is located. Then it is ejected upward from the support plate, forming an upward airflow in the kiln body. At the same time, it flows a distance towards the kiln head and enters the next gas distribution channel. This process continues. The high-temperature gas continuously circulates in the kiln body and each gas distribution channel. At the same time, some of the high-temperature gas in the first half of the sintering zone is returned to the second half of the sintering zone through the return gas channel and reintroduced into the kiln body to sinter the brick blanks. After sintering is completed, the brick blanks enter the homogenization zone to eliminate internal stress. ④ Brick blank cooling: The brick blanks are driven into the cooling zone by the kiln car and are slowly cooled in the cooling zone. During the cooling process, cold air is introduced into the air inlet chambers on both sides of the cooling zone and then blown into the kiln body through the cold air inlet. At the same time, some cold air is blown into the space where the support block is located and then sprayed upward from the support perforated plate. The heat-absorbing gas enters the exhaust chamber and is discharged from the exhaust chamber, thus completing the cooling of the brick blanks. ⑤ Brick blanks exiting the kiln: Open the kiln door and the kiln car will send the cooled brick blanks out of the tunnel kiln.

[0012] Furthermore, in step ③, a heat insulation layer is provided on the outer wall of the return air passage.

[0013] Furthermore, in step ③, multiple sets of temperature sensors are spaced apart along the length of the kiln body in the sintering zone, with each set of temperature sensors located at the upper and lower parts of the kiln body, respectively.

[0014] The beneficial effects of this invention are as follows: 1. Coal gangue bricks are stacked on kiln cars and transported to the preheating zone. They then slowly move from the preheating zone towards the firing zone. Simultaneously, high-temperature gas generated in the firing zone flows towards the preheating zone. Upon entering the preheating zone, the higher-temperature gas at the top of the kiln flows into the gas distribution channel, flows downwards along the channel, and is ejected from the jet vents on both sides of the kiln, entering the space where the support blocks are located. It then ejects upwards from the support perforated plates, forming an upward-flowing airflow within the kiln. This process allows the higher-temperature gas to re-enter the bottom of the kiln and flow upwards, contacting the brick blanks during this flow to heat, dry, and preheat them, ensuring thorough drying. By utilizing the waste heat of the high-temperature gas, most of the high-temperature gas flows towards the kiln head within the kiln body to heat, dry, and preheat the brick blanks. The high-temperature gas with relatively high temperature is returned to the bottom of the kiln body for further utilization. On the one hand, the upward flow of the high-temperature gas averages the longitudinal temperature difference within the kiln body, which is beneficial for the preheating of the brick blanks. On the other hand, it can further improve the utilization rate of the high-temperature gas, reduce the waste of heat in the high-temperature gas, and lower the temperature of the high-temperature flue gas when it is discharged. At the same time, waste heat utilization devices and exhaust gas treatment devices are set up to recover and utilize the waste heat in the high-temperature gas again, and after completing the filtration and purification treatment, it is discharged to reduce environmental pollution.

[0015] 2. After the brick blanks are preheated, they are driven by kiln cars into the heating zone, sintering zone, and homogenization zone in sequence. In the heating zone, the brick blanks soften and begin sintering. Upon entering the sintering zone, during the sintering process, the high-temperature gas rises and enters the gas distribution channel through the upper air vents. It is then ejected from the jet vents on both sides of the kiln body, entering the space where the support blocks are located, and then ejected upwards from the support perforated plates, forming an upward airflow within the kiln body. Simultaneously, it flows a distance towards the kiln head and enters the next gas distribution channel, and so on. The high-temperature gas continuously circulates within the kiln body and each gas distribution channel, and the flue gas... During the upward flow process, the temperature in the lower part of the kiln is increased, the longitudinal temperature difference in the kiln is averaged, and the temperature difference between the upper and lower parts of the kiln is reduced. At the same time, some of the high-temperature gas in the first half of the sintering zone is returned to the second half of the sintering zone through the return gas channel and reintroduced into the kiln to sinter the brick blanks. This prolongs the sintering time between the high-temperature gas and the brick blanks, makes fuller use of the heat in the high-temperature gas, and ensures that the brick blanks are fully sintered in the core sintering zone, thereby improving the heat utilization rate and the sintering quality of the bricks. After sintering, the brick blanks enter the homogenization zone to eliminate internal stress.

[0016] Third, during the cooling of sintered bricks, on the one hand, cold air sprayed from both sides of the kiln body is used to cool the sintered bricks, and on the other hand, some cold air is also sprayed upward from the lower part of the kiln body, so that the cooling effect of the sintered bricks is better and more uniform.

[0017] This invention incorporates a gas distribution channel in the preheating zone to transport high-temperature gas from the top of the kiln to the lower part. This high-temperature gas flows upwards, averaging the longitudinal temperature difference within the kiln, which is beneficial for preheating the bricks. Furthermore, it improves the utilization rate of the high-temperature gas, reduces heat waste, and lowers the temperature of the exhaust gas. Simultaneously, a waste heat recovery device and a waste gas treatment device are installed to further recover and utilize the waste heat from the high-temperature gas, and the gas is filtered and purified before discharge, reducing environmental pollution. Similarly, a gas distribution channel is set in the core sintering zone to transport high-temperature gas from the top of the kiln to the lower part. This high-temperature gas... The upward flow of gas evens out the longitudinal temperature difference within the kiln, which is beneficial for the sintering of the bricks. Simultaneously, a portion of the high-temperature gas from the front half of the sintering zone is returned to the rear half via the reflux gas channel, and then reintroduced into the kiln to sinter the bricks. This extends the sintering time between the high-temperature gas and the bricks, making fuller use of the heat in the gas and ensuring thorough sintering of the bricks within the core sintering zone. This improves heat utilization and the sintering quality of the bricks. Furthermore, during the cooling process, cold air is sprayed from both sides of the kiln for cooling, while some cold air is also sprayed upwards from the lower part of the kiln, resulting in better and more uniform cooling. In summary, this invention offers advantages such as high thermal energy utilization, excellent brick heating effect, uniform temperature distribution, and energy efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of sintering zone 7 in this invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the cooling band 2 in this invention; In the diagram: 1-Preheating zone, 2-Cooling zone, 3-Kiln car, 4-Support perforated plate, 5-Support block, 6-Heating zone, 7-Sintering zone, 8-Soaking zone, 9-Baffle, 10-Gas distribution channel, 11-Air jet hole, 12-Recirculation channel, 13-Inlet chamber, 14-Cold air inlet, 15-Waste heat utilization device, 16-Waste gas treatment device, 17-Bottom blowing chamber, 18-Side blowing hole, 19-Baffle, 20-Filter screen, 21-Dust removal port, 22-Insulation layer, 23-Temperature sensor. Detailed Implementation

[0019] The present invention will be further described below with reference to the embodiments and accompanying drawings, but this does not limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0020] like Figures 1-3As shown, the energy-saving and environmentally friendly tunnel kiln for coal gangue brick sintering of the present invention includes a kiln body and a slide rail installed inside the kiln body. The kiln body, along its length, includes a preheating zone 1, a firing zone, and a cooling zone 2. A kiln car 3 is installed on the slide rail. An insulation layer and a refractory layer are sequentially installed on the kiln car 3. A support perforated plate 4 is installed on the refractory layer. Several support blocks 5 are arranged in a spaced array between the support perforated plate 4 and the refractory layer. The support perforated plate 4 is used to support the brick blanks, and it also has several through holes. The support blocks 5 are used to support the support perforated plate 4, and there are several interconnected channels between the support blocks 5, allowing high-temperature gas to enter first. Some channels are used, and then the gas is sprayed upward from the through holes of the support plate 4. When stacking sintered bricks, as many through holes as possible should be left. The firing zone includes the heating zone 6, the sintering zone 7, and the soaking zone 8 in sequence. The sintering zone 7 is the core high-temperature sintering part of the firing zone and is the core of the entire tunnel kiln process. The temperature of the entire sintering zone 7 is high and relatively stable, and the temperature in the middle of the sintering zone 7 is the highest, while the temperature on both sides is slightly lower and the difference is not significant. This is also the basis for the present invention to use the return gas channel 12 to return the high-temperature gas in the first half of the sintering zone 7 to the second half of the sintering zone 7 in a regular manner. The top and two sides of the sintering zone 7 and the preheating zone 2 are... The kiln body is provided with a connecting airflow channel on the side, which is divided into several independent inverted U-shaped air distribution channels 10 by a partition 9. The top of the kiln body is provided with an upper air hole connected to each air distribution channel. The sides of the kiln body are provided with jet nozzles 11 connected to each air distribution channel 10. The jet nozzles 11 jet towards the support block 5. The frontmost and rearmost air distribution channels 10 of the sintering zone 7 are connected, as are the next frontmost and next rearmost air distribution channels 10, and so on. The air channels 10 in the front half and the air distribution channels 10 in the rear half of the sintering zone 7 are connected by a return air channel 12. Cooling zone 2... An air inlet chamber 13 is provided inside the side walls of the kiln on both sides. The air inlet chamber 13 is connected to the inside of the kiln through a cold air inlet 14. The cold air inlet 14 at the bottom faces the support block 5. An exhaust chamber is provided at the top of the cooling zone 2. The top of the front end of the preheating zone 1 is connected to a waste heat recovery device 15 and a waste gas treatment device 16 in sequence through an exhaust pipe. Both the waste heat recovery device 15 and the waste gas treatment device 16 are existing equipment. The waste heat recovery device 15 further recovers and utilizes the waste heat in the flue gas, and the waste gas treatment device 16 is used to filter and purify the flue gas to meet the relevant emission standards and reduce environmental pollution.

[0021] A bottom-blowing air chamber 17 is provided in the kiln body at the bottom of the cooling zone 2. The top of the bottom-blowing air chamber 17 is connected to the inside of the kiln body through the top-blowing hole. Cold air is introduced into the bottom-blowing air chamber 17 and then sprayed into the kiln through the top-blowing hole. The kiln car 3 is located at the bottom of the kiln. Therefore, the sprayed cold air will be sprayed directly onto the kiln car 3 to cool the metal components, wheel sets and sand seal parts of the kiln car 3, avoid high temperature deformation and bearing overheating, extend the service life of the equipment, and at the same time, it can gradually reduce the temperature of the brick blank from bottom to top.

[0022] Side blowing holes 18 connected to the gas distribution channel 10 are provided on both sides of the sintering zone 7 and the preheating zone 1. The side blowing holes 18 on each gas distribution channel 10 are arranged vertically at intervals. High-temperature gas enters the airflow channel from the top of the kiln and is then injected into the kiln from the jet hole 11, forming an upward airflow. With the addition of the side blowing holes 18, some of the high-temperature gas will be injected into the kiln from the side blowing holes 18, thus forming a state in which high-temperature gas is injected from both sides and the bottom at the same time. The preheating and sintering of the brick blanks are more uniform, improving the sintering quality of the brick blanks.

[0023] Each gas distribution channel 10 is equipped with a baffle 19 at the top of the kiln body. The baffle 19 is located on the side of the upper gas hole near the kiln head. In the kiln body, the gas with higher temperature has lower density and naturally rises. High temperature gas continuously accumulates at the top of the kiln, and the temperature is higher at the top and lower at the bottom. Due to the flow resistance problem, the resistance to direct forward flow is smaller. The high temperature gas will flow directly along the top of the kiln towards the preheating zone 1, which is not conducive to the high temperature flue gas entering the airflow channel. Therefore, the baffle 19 is set to block the forward flow of high temperature gas, increase the forward flow resistance, and allow the high temperature gas located at the top of the kiln to smoothly enter the airflow channel.

[0024] Filter screens 20 are installed in the airflow channels on both sides of the sintering zone 7 and the preheating zone 1. The filter screens 20 are closely attached to the side wall of the airflow channel facing the inside of the kiln. The high-temperature gas generated in the sintering zone 7 contains a large amount of dust and other impurities. The filter screens 20 can filter out some of the dust, reduce the load of subsequent gas treatment, and at the same time prevent a large amount of dust, fly ash, carbon dust and refractory particles from falling on the brick blanks and affecting the firing quality of the brick blanks.

[0025] At the bottom of the airflow channels on both sides of the sintering zone 7 and the preheating zone 1, there are dust removal ports 21. The airflow channels are located in the sintering zone 7 and the preheating zone 1, and the airflow channels are divided into several gas distribution channels 10. High-temperature gas enters the gas distribution channel 10, and flows downward to both sides at the top of the gas distribution channel 10. Then it is sprayed into the kiln body through the jet hole 11. When the high-temperature gas flows in the gas distribution channel 10, due to collision, gravity settling and other reasons, some dust and other impurities in the high-temperature gas will be separated from it and continuously deposited in the gas distribution channel 10. Over time, this may cause the jet hole 11 to become blocked. Therefore, the dust removal ports 21 are set up. The dust removal ports 21 can be opened periodically according to the actual situation to clean the deposited dust and keep the jet hole 11 unobstructed.

[0026] The sintering process of the energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to the present invention includes the following steps: ① Brick blanks are loaded into the kiln: The brick blanks are placed on the support plate 4 of the kiln car 3, the kiln door is opened, the kiln car 3 carries the brick blanks into the preheating zone 1, and the kiln door is closed. ② Brick preheating: The high-temperature gas generated by the firing zone flows towards the preheating zone 1 and enters the preheating zone 1 to heat and dry the brick blank, thus completing the preheating of the brick blank. During the preheating process, the high-temperature gas rises and enters the gas distribution channel 10 through the upper air hole, and then is ejected from the jet holes 11 on both sides of the kiln body, injected into the space where the support block 5 is located, and then ejected upward from the support hole plate 4, forming an upward airflow in the kiln body. At the same time, it flows a distance towards the kiln head and enters the next gas distribution channel 10, and so on. Finally, it is sent from the exhaust pipe to the waste heat utilization device 15 and the waste gas treatment device 16 to complete the waste heat utilization and waste gas treatment before being discharged. ③ Brick sintering: The brick blanks are driven into the sintering zone by the kiln car 3. After preheating, the brick blanks gradually enter the heating zone 6, sintering zone 7, and homogenization zone 8 of the sintering zone. When entering the heating zone 6, the brick blanks soften and begin sintering. When entering the sintering zone 7, the sintering of the brick blanks is completed. During the sintering process, the high-temperature gas rises and enters the gas distribution channel 10 through the upper gas hole. Then it is ejected from the jet holes 11 on both sides of the kiln body and sprayed into the space where the support block 5 is located. Then it is ejected upward from the support hole plate 4, forming an upward airflow in the kiln body. At the same time, it flows a distance towards the kiln head and enters the next gas distribution channel 10, and so on. The high-temperature gas continuously circulates in the kiln body and each gas distribution channel 10. Simultaneously, some of the high-temperature gas from the front half of the sintering zone 7 is returned to the rear half of the sintering zone 7 through the return gas duct 12, and then reintroduced into the kiln to sinter the brick blanks. After sintering, the brick blanks enter the homogenizing zone 8 to eliminate internal stress. Multiple sets of temperature sensors 23 are spaced along the length of the kiln within the sintering zone 7. Each set of temperature sensors 23 is located at the upper and lower parts of the kiln. The multiple sets of temperature sensors 23 along the length of the sintering zone 7 allow for horizontal temperature control of various parts of the sintering zone 7. Furthermore, the vertical arrangement of each set of temperature sensors 23 allows for temperature control of the upper and lower parts of the same cross-section of the sintering zone 7, which is beneficial for controlling the sintering temperature of the bricks. A heat insulation layer 22 is installed on the outer wall of the return gas duct 12. While some of the high-temperature gas from the front half of the sintering zone 7 returns to the rear half of the sintering zone 7 through the return gas duct 12, some heat loss occurs during transport. The heat insulation layer 22 reduces energy loss and improves heat utilization.

[0027] ④ Brick blank cooling: The brick blank enters the cooling zone 2 under the drive of the kiln car 3 and is slowly cooled in the cooling zone 2. During the cooling process, cold air is introduced into the air inlet chambers 13 on both sides of the cooling zone 2, and then blown into the kiln body through the cold air inlet 14. At the same time, some cold air is blown into the space where the support block 5 is located, and then sprayed upward from the support hole plate 4. The heat-absorbing gas enters the exhaust chamber and is discharged from the exhaust chamber, thus completing the cooling of the brick blank. ⑤ Brick blanks exiting the kiln: Open the kiln door and kiln car 3 will send the cooled brick blanks out of the tunnel kiln.

[0028] In this invention, coal gangue bricks are stacked on kiln cars 3 and fed into the preheating zone 1. They then slowly move from the preheating zone 1 towards the firing zone. Simultaneously, high-temperature gas generated in the firing zone flows towards the preheating zone 1. After flowing into the preheating zone 1, the high-temperature gas at the top of the kiln body in the preheating zone 1 flows into the gas distribution channel 10, flows downwards along the channel 10, and is ejected from the jet holes 11 on both sides of the kiln body, entering the space where the support block 5 is located. Then, it is ejected upwards from the support perforated plate 4, forming an upward-flowing airflow within the kiln body. This process allows the high-temperature gas to re-enter the bottom of the kiln body and then flow upwards, contacting the brick blanks during the flow to heat and dry them. Preheating fully utilizes the waste heat of the high-temperature gas. Similarly, most of the slightly lower-temperature high-temperature gas flows towards the kiln head inside the kiln to heat, dry, and preheat the brick blanks. The higher-temperature gas is returned to the bottom of the kiln for further utilization. On the one hand, the upward flow of the high-temperature gas reduces the longitudinal temperature difference inside the kiln, which is beneficial for the preheating of the brick blanks. On the other hand, it can further improve the utilization rate of the high-temperature gas, reduce the waste of heat in the high-temperature gas, and lower the temperature of the high-temperature flue gas when it is discharged. At the same time, a waste heat utilization device 15 and a waste gas treatment device 16 are set up to recover and utilize the waste heat in the high-temperature gas again, and after filtration and purification treatment, it is discharged to reduce environmental pollution.

[0029] After the brick blanks are preheated, they are driven by kiln car 3 into heating zone 6, sintering zone 7, and homogenizing zone 8 in sequence. In heating zone 6, the brick blanks soften and begin sintering. After entering sintering zone 7, during the sintering process, the high-temperature gas rises and enters the gas distribution channel 10 through the upper air hole. It is then ejected from the air jet holes 11 on both sides of the kiln body, injected into the space where the support block 5 is located, and then ejected upwards from the support perforated plate 4, forming an upward airflow within the kiln body. At the same time, it flows a certain distance towards the kiln head, and the high-temperature gas enters the next gas distribution channel 10, and so on. The high-temperature gas continuously flows within the kiln body and each gas distribution channel. In the internal circulation of 10, the flue gas flows from bottom to top, increasing the temperature in the lower part of the kiln and reducing the longitudinal temperature difference within the kiln, as well as the temperature difference between the upper and lower parts of the kiln. Simultaneously, some of the high-temperature gas from the first half of the sintering zone 7 is returned to the second half of the sintering zone 7 through the return gas channel 12, and then reintroduced into the kiln to sinter the brick blanks. This prolongs the sintering time between the high-temperature gas and the brick blanks, making fuller use of the heat in the high-temperature gas, so that the brick blanks are fully sintered in the core sintering zone 7, improving the heat utilization rate and the sintering quality of the bricks. After sintering, the brick blanks enter the homogenization zone 8 to eliminate internal stress.

[0030] During the cooling of sintered bricks, cold air is sprayed from both sides of the kiln to cool the bricks. On the other hand, some cold air is also sprayed upwards from the lower part of the kiln, resulting in a better and more uniform cooling effect for the sintered bricks.

[0031] In summary, this invention incorporates a gas distribution channel 10 in the preheating zone 1 to transport high-temperature gas from the top of the kiln to the lower part. This high-temperature gas flows upwards, reducing the longitudinal temperature difference within the kiln and facilitating the preheating of the brick blanks. Furthermore, it improves the utilization rate of the high-temperature gas, reduces heat waste, and lowers the temperature of the exhaust gas. Simultaneously, a waste heat recovery device 15 and a waste gas treatment device 16 are installed to further recover and utilize the waste heat from the high-temperature gas, and the gas is then filtered and purified before discharge, reducing heat waste and environmental pollution. Similarly, a gas distribution channel 10 is also incorporated in the core sintering zone 7 to transport high-temperature gas from the top of the kiln to the lower part. This high-temperature gas flows upwards, reducing the longitudinal temperature difference within the kiln and facilitating the sintering of the brick blanks. Meanwhile, some of the high-temperature gas from the front half of the sintering zone 7 is returned to the rear half of the sintering zone 7 through the return gas channel 12, and then reintroduced into the kiln to sinter the brick blanks. This prolongs the sintering time between the high-temperature gas and the brick blanks, making fuller use of the heat in the high-temperature gas, so that the brick blanks are fully sintered in the core sintering zone 7, improving the heat utilization rate and the sintering quality of the sintered bricks. In addition, when the sintered bricks are cooled, on the one hand, cold air is sprayed from both sides of the kiln to cool the sintered bricks, and on the other hand, some cold air is also sprayed upward from the lower part of the kiln, resulting in a better and more uniform cooling effect for the sintered bricks.

Claims

1. An energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks, comprising a kiln body and a slide rail disposed within the kiln body, wherein the kiln body comprises, along its length, a preheating zone (1), a firing zone, and a cooling zone (2), characterized in that... The slide rail is equipped with a kiln car (3), and the kiln car (3) is equipped with a heat insulation layer and a refractory layer in sequence. The refractory layer is equipped with a support perforated plate (4), and a number of support blocks (5) are arranged in an array between the support perforated plate (4) and the refractory layer. The firing zone includes a heating zone (6), a sintering zone (7), and a homogenizing zone (8) in sequence. The top and sides of the sintering zone (7) and the preheating zone (2) are equipped with airflow channels that are connected. The airflow channels are divided into a number of independent inverted U-shaped gas channels (10) by partitions (9). The top of the kiln body is equipped with an upper air hole that is connected to each gas channel. The sides of the kiln body are equipped with jet holes (11) that are connected to each gas channel (10). The jet direction of the jet holes (11) is towards the support blocks (5). In the direction, the frontmost gas distribution channel (10) and the rearmost gas distribution channel (10) of the sintering zone (7) are connected by a return gas channel (12), and the gas channel (10) of the second front end and the second rear end are connected by a return gas channel (12). An air inlet chamber (13) is provided in the side wall of the kiln on both sides of the cooling zone (2). The air inlet chamber (13) is connected to the inside of the kiln through a cold air inlet (14). The cold air inlet (14) at the bottom faces the support block (5). An exhaust chamber is provided at the top of the cooling zone (2). The top of the front end of the preheating zone (1) is connected to a waste heat utilization device (15) and a waste gas treatment device (16) in sequence through an exhaust pipe.

2. The energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 1, characterized in that... The bottom of the cooling zone (2) is provided with a bottom blowing chamber (17) in the kiln body, and the top of the bottom blowing chamber (17) is connected to the inside of the kiln body through a top blowing hole.

3. The energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 1, characterized in that... The sintering zone (7) and the preheating zone (1) are provided with side blowing holes (18) that communicate with the gas distribution channel (10) on both sides, and the side blowing holes (18) provided on each gas distribution channel (10) are arranged at intervals.

4. The energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 1, characterized in that... Each gas distribution channel (10) is provided with a baffle (19) on the top of the kiln body below it. The baffle (19) is located on the side of the upper gas hole near the kiln head.

5. The energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 1, characterized in that... Filter screens (20) are installed in the airflow channels on both sides of the sintering zone (7) and the preheating zone (1). The filter screens (20) are tightly attached to the side wall of the airflow channel facing the inside of the kiln.

6. The energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 1, characterized in that... The bottom of the airflow channels on both sides of the sintering zone (7) and the preheating zone (1) is provided with a dust removal port (21).

7. The sintering process of an energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 1, characterized in that: Includes the following steps: ① Brick blanks are placed in the kiln: The brick blanks are placed on the support plate (4) of the kiln car (3), the kiln door is opened, the kiln car (3) carries the brick blanks into the preheating zone (1), and the kiln door is closed. ② Brick preheating: The high-temperature gas generated by the firing zone flows towards the preheating zone (1) and enters the preheating zone (1) to heat and dry the brick blank, thus completing the preheating of the brick blank. During the preheating process, the high-temperature gas with a higher temperature floats up and enters the gas distribution channel (10) through the upper air hole. Then it is sprayed out from the jet holes (11) on both sides of the kiln body and sprayed into the space where the support block (5) is located. Then it is sprayed upward from the support hole plate (4) to form an upward airflow in the kiln body. At the same time, it flows a distance towards the kiln head and enters the next gas distribution channel (10). This process is repeated. Finally, the gas is sent from the exhaust pipe to the waste heat utilization device (15) and the waste gas treatment device (16) to complete the waste heat utilization and waste gas treatment before being discharged. ③ Sintering of brick blanks: The brick blanks are driven into the sintering zone by the kiln car (3). After preheating, the brick blanks gradually enter the heating zone (6), sintering zone (7) and homogenization zone (8) of the sintering zone. When entering the heating zone (6), the brick blanks soften and begin to sinter. When entering the sintering zone (7), the sintering of the brick blanks is completed. During the sintering process, the high-temperature gas rises and enters the gas distribution channel (10) through the upper gas hole. Then it is sprayed out from the jet holes (11) on both sides of the kiln body and sprayed into the space where the support block (5) is located. Then it is sprayed out from the support hole plate. (4) The gas is sprayed upwards, forming an upward flow in the kiln body. At the same time, it flows a distance towards the kiln head and enters the next gas distribution channel (10). This process is repeated. The high-temperature gas continuously circulates in the kiln body and each gas distribution channel (10). Meanwhile, through the return gas channel (12), some of the high-temperature gas in the front half of the sintering zone (7) is returned to the rear half of the sintering zone (7) and then introduced into the kiln body again to sinter the brick blanks. After sintering is completed, the brick blanks enter the heat equalization zone (8) to eliminate internal stress. ④ Brick blank cooling: The brick blank enters the cooling zone (2) driven by the kiln car (3) and is slowly cooled in the cooling zone (2). During the cooling process, cold air is introduced into the air inlet chamber (13) on both sides of the cooling zone (2) and then blown into the kiln body through the cold air inlet (14). At the same time, some cold air is blown into the space where the support block (5) is located and then sprayed upward from the support hole plate (4). The heat-absorbing gas enters the exhaust chamber and is discharged from the exhaust chamber, thus completing the cooling of the brick blank. ⑤ Brick blanks are removed from the kiln: Open the kiln door and send the cooled brick blanks out of the tunnel kiln by the kiln car (3).

8. The sintering process of an energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 7, characterized in that: In step ③, a heat insulation layer (22) is provided on the outer wall of the return air passage (12).

9. The sintering process of an energy-saving and environmentally friendly tunnel kiln for sintering coal gangue bricks according to claim 7, characterized in that: In step ③, multiple sets of temperature sensors (23) are arranged at intervals along the length of the kiln body in the sintering zone (7), and each set of temperature sensors (23) is respectively located in the upper and lower parts of the kiln body.

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