A high-efficiency preheating and decomposing device for cement raw material based on waste heat
Patent Information
- Application Number
- CN202522109917.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2026-09-04
- Estimated Expiration
- 2035-09-30
AI Technical Summary
[0003]目前，水泥生料的预热分解装置在运行过程中还存在以下问题：一是分解炉是碱、氯、硫等有害成分循环富集的关键区域，这些挥发性物质会在分解炉的中下部温度合适区域形成液相，像胶水一样粘附生料颗粒，在炉壁形成坚硬结皮，减小通风截面，严重时导致停窑清理，影响系统的正常运行；二是生料喂入分解炉后，不能均匀地分散在整个炉膛空间与热气流充分接触，部分生料可能会沿炉壁短路，迅速通过分解炉，降低了生料的分解率，还容易导致末级预热器下料管冷却堵塞
[0011]本实用新型运行时，从水泥窑窑尾排出的烟气从烟气入口进入分解炉，然后从下向上流动，同时，从下三次风管向夹套内部通入高温空气，高温空气在夹套内螺旋向上流动，经预热的生料从撒料盒投入夹套，水泥生料经初步打散后随螺旋高温空气流动，在流动过程中，生料不断冲击在散料板上，可进一步将生料结块和料股打散，使得生料进一步分散，最后生料从喷料口喷入中壳体内部，并均匀分散在其中，同时，煤粉喷枪和上三次风管分别通入煤粉和高温空气并形成上升的螺旋气流，煤粉燃烧，提高内部温度，生料在上升过程中不断与高温烟气接触，生料中的碳酸钙受热分解，最后从物料出口排出，分离其中的气体后，送入水泥窑进行后续的烧成生产工艺。在本实用新型中，水泥生料通过撒料盒投入夹套，进行初次散料，夹套内通入有螺旋上升流动的高温空气，高温空气带动生料流动，在流动过程中，会不断与散料板碰撞，在冲击和碰撞过程中，生料中还存在的结块进一步被打散，最后生料随同气流从喷料口喷入壳体内部，通过上述过程，可使得生料均匀分散在气流中，进而均匀分布在分解炉的整个炉膛空间，使其与热气流充分接触，避免出现传统工艺中生料分布不均的问题，提高生料的分解率；其次，针对目前分解炉中下部内壁上存在的碱、氯、硫等有害成分富集，粘附生料颗粒在炉壁上形成坚硬结皮的问题，设置了空气炮，在实际运行过程中，可定期开启空气炮，利用瞬间喷出的强大冲击气流，有效地将刚刚形成的、尚不坚固的结皮吹扫下来，防止结皮增厚增强，确保分解炉内物料和气流的顺畅流通，避免出现因结皮而导致的堵塞问题，不需停窑清理，保证系统的正常运行；另外，通过夹套的设置，在夹套内通入了三次风，三次风是水泥窑篦冷机抽取输送至分解炉的、富含氧气的高温助燃空气，其热量来自于水泥窑排出的熟料，三次风进入夹套具有三个方面的作用，其一是利用三次风中的热量对生料进行加热，利用了篦冷机中水泥熟料的余热，其二是对分解炉进行了保温，避免分解炉内的四周因热量散失而降温，消除炉内的局部低温区，使得炉内中心与四周温度更为均匀，进而确保生料的分解效率，其三是利用三次风的动力，即可带动生料流动，又可以对生料进行一定的冲击，使得生料更加分散。综上所述，本实用新型具有不易结皮，生料不易短路，分解率高，利用了熟料余热的优点。
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Figure CN224719175U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of cement raw meal preheating and decomposition equipment, specifically to a high-efficiency cement raw meal preheating and decomposition device based on waste heat. Background Technology
[0002] The most energy-intensive process in cement production is the decomposition of calcium carbonate in raw materials. This decomposition requires a large amount of heat, and traditional processes complete this in a rotary kiln, resulting in low efficiency and high energy consumption. Preheating decomposition devices, by moving this process outside the rotary kiln, reduce the burden on the kiln, which primarily focuses on calcination, thus increasing its output. The raw material waste heat decomposition device mainly consists of a preheater and a decomposition furnace. The raw materials undergo four to five stages of preheating, raising their temperature to 800℃–850℃, while the exhaust gas temperature drops to 300℃–350℃, maximizing heat recovery. The raw materials decompose within the decomposition furnace, achieving a calcium carbonate decomposition rate of over 90%–95%.
[0003] Currently, the preheating and decomposition devices for cement raw materials still face the following problems during operation: First, the decomposition furnace is a critical area for the cyclic accumulation of harmful components such as alkali, chlorine, and sulfur. These volatile substances form a liquid phase in the suitable temperature zone of the lower part of the decomposition furnace, adhering to raw material particles like glue and forming a hard crust on the furnace wall. This reduces the ventilation cross-section and, in severe cases, leads to kiln shutdown for cleaning, affecting the normal operation of the system. Second, after the raw materials are fed into the decomposition furnace, they cannot be evenly dispersed throughout the furnace space to fully contact the hot airflow. Some raw materials may short-circuit along the furnace wall and quickly pass through the decomposition furnace, reducing the decomposition rate and easily causing cooling blockage in the feed pipe of the final preheater. Therefore, it is objectively necessary to develop a high-efficiency preheating and decomposition device for cement raw materials based on waste heat that is less prone to crusting, short-circuiting of raw materials, and high decomposition rate. Utility Model Content
[0004] The purpose of this invention is to provide a high-efficiency preheating and decomposition device for cement raw materials based on waste heat, which is less prone to crusting, less prone to short circuits in raw materials, and has a high decomposition rate.
[0005] The purpose of this utility model is achieved as follows: it includes a decomposition furnace and a material outlet located at the top of the decomposition furnace. A flue gas inlet is located at the bottom of the decomposition furnace. The decomposition furnace includes, from top to bottom, an upper shell, a middle shell, and a bottom cone connected in sequence. An integral jacket is provided on the outer side of the middle shell and the bottom cone. The bottom of the jacket is tangentially connected to a lower tertiary air duct. A material distribution box is connected above the lower tertiary air duct. A spiral rod is provided inside the jacket. Several material distribution plates are spaced apart on the spiral rod. Multiple rows of spray nozzles are spaced vertically on the middle shell above the jacket. The spray direction of the spray nozzles is inclined downwards. Multiple pulverized coal spray guns and upper tertiary air ducts are evenly distributed along the circumference of the lower part of the middle shell. The pulverized coal spray guns and upper tertiary air ducts are staggered on the circumference. Air cannons are provided on both the middle shell and the bottom cone. The nozzles of the air cannons on the middle shell are tangentially arranged, and the nozzles of the air cannons on the bottom cone are inclined downwards.
[0006] Furthermore, the sidewalls of the bulk material plate are provided with multiple protrusions with sharp tops.
[0007] Furthermore, the air cannons are arranged in 2 to 3 rows on the middle shell and the bottom cone, with the upper and lower adjacent rows of air cannons staggered on the circumference.
[0008] Furthermore, each row of nozzles is evenly distributed along the circumference of the middle shell, with adjacent rows of nozzles arranged alternately, and the angle between the nozzle direction and the vertical center line gradually decreases from top to bottom.
[0009] Furthermore, the diameter of each row of spray nozzles gradually increases from top to bottom.
[0010] Furthermore, a burner is provided at the lower part of the upper casing.
[0011] In operation, the flue gas discharged from the tail of the cement kiln enters the decomposition furnace through the flue gas inlet and then flows upward. At the same time, high-temperature air is introduced into the jacket through the lower tertiary air duct. The high-temperature air spirals upward inside the jacket. The preheated raw material is fed into the jacket from the feeding box. After being initially dispersed, the cement raw material flows with the spiral high-temperature air. During the flow, the raw material continuously impacts the feeding plate, which further disperses the raw material clumps and material strands, making the raw material more dispersed. Finally, the raw material is sprayed into the middle shell from the spray nozzle and evenly dispersed therein. At the same time, pulverized coal and high-temperature air are introduced into the pulverized coal spray gun and the upper tertiary air duct, respectively, forming an upward spiral airflow. The pulverized coal burns, increasing the internal temperature. During the upward process, the raw material continuously comes into contact with the high-temperature flue gas. The calcium carbonate in the raw material decomposes due to heat and is finally discharged from the material outlet. After the gas is separated, it is sent to the cement kiln for subsequent firing production processes. In this invention, cement raw meal is initially dispersed by feeding it into the jacket via a feeding box. High-temperature air, spiraling upwards, flows through the jacket, carrying the raw meal. During this flow, the raw meal continuously collides with the feeding plate, further breaking up any remaining clumps. Finally, the raw meal is sprayed into the shell through the nozzle along with the airflow. This process ensures the raw meal is evenly dispersed in the airflow and distributed throughout the entire furnace chamber of the decomposition furnace, allowing it to fully contact the hot airflow and avoiding the uneven distribution problem found in traditional processes, thus improving the decomposition rate. Secondly, addressing the problem of harmful components such as alkali, chlorine, and sulfur accumulating on the lower inner wall of the decomposition furnace and forming a hard crust of adhering raw meal particles, an air cannon is installed. During actual operation, the air cannon can be periodically activated, using a powerful, instantaneous jet of airflow to effectively disperse the newly formed, still-soft crust. Solid crusts are blown off to prevent them from thickening and strengthening, ensuring smooth flow of materials and airflow within the decomposition furnace and avoiding blockages caused by crusts. This eliminates the need for kiln shutdown for cleaning, ensuring normal system operation. Furthermore, the jacket design introduces tertiary air, which is high-temperature, oxygen-rich combustion air drawn from the cement kiln grate cooler and delivered to the decomposition furnace. Its heat comes from the clinker discharged from the cement kiln. The tertiary air serves three purposes: firstly, it heats the raw materials using the residual heat from the cement clinker in the grate cooler; secondly, it insulates the decomposition furnace, preventing heat loss and cooling around the perimeter, eliminating localized low-temperature zones, and ensuring a more uniform temperature distribution between the center and perimeter, thus guaranteeing efficient raw material decomposition; and thirdly, the tertiary air's power drives the flow of raw materials and provides impact, further dispersing them. In summary, this invention has the advantages of being less prone to crusting, less prone to short circuits in raw materials, having a high decomposition rate, and utilizing the waste heat of clinker. Attached Figure Description
[0012] Figure 1This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the connection structure between the screw rod 6 and the material distribution plate 7 in this utility model; In the diagram: 1-Decomposition furnace, 2-Flue gas inlet, 3-Jacket, 4-Lower tertiary air duct, 5-Feeding box, 6-Screw rod, 7-Feeding plate, 8-Feeding nozzle, 9-Pulverized coal spray gun, 10-Upper tertiary air duct, 11-Air cannon, 12-Protrusion, 13-Burner. Detailed Implementation
[0013] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.
[0014] like Figures 1-2 As shown, this utility model includes a decomposition furnace 1 and a material outlet located at the top of the decomposition furnace 1. A flue gas inlet 2 is located at the bottom of the decomposition furnace 1. The decomposition furnace 1 includes an upper shell, a middle shell, and a bottom cone connected sequentially from top to bottom. An integral jacket 3 is provided on the outer side of the middle shell and the bottom cone. A lower tertiary air duct 4 is tangentially connected to the bottom of the jacket 3. A material distribution box 5 is connected above the lower tertiary air duct 4. A spiral rod 6 is provided inside the jacket 3. Several material distribution plates 7 are spaced apart on the spiral rod 6. Multiple rows of spray nozzles 8 are spaced apart on the upper middle shell of the jacket 3. The spray direction of the spray nozzles 8 is inclined downward. Multiple coal powder spray guns 9 and upper tertiary air ducts 10 are evenly distributed along the circumference of the lower part of the middle shell. The coal powder spray guns 9 and upper tertiary air ducts 10 are staggered on the circumference. Air cannons 11 are provided on both the middle shell and the bottom cone. The nozzles of the air cannons 11 on the middle shell are arranged horizontally and tangentially, while the nozzles of the air cannons 11 on the bottom cone are arranged inclined downward.
[0015] In operation, the flue gas discharged from the tail of the cement kiln enters the decomposition furnace 1 through the flue gas inlet 2 and then flows upward. At the same time, high-temperature air is introduced into the jacket 3 through the lower tertiary air duct 4. The high-temperature air spirals upward in the jacket 3. The preheated raw material is fed into the jacket 3 through the feeding box 5. After being initially dispersed, the cement raw material flows with the spiral high-temperature air. During the flow, the raw material continuously impacts the material distribution plate 7, which can further disperse the raw material clumps and material strands, making the raw material more dispersed. Finally, the raw material is sprayed into the middle shell through the spray nozzle 8 and evenly dispersed therein. At the same time, pulverized coal spray gun 9 and upper tertiary air duct 10 respectively introduce pulverized coal and high-temperature air, forming an upward spiral airflow. The pulverized coal burns, increasing the internal temperature and providing the heat required for decomposition. During the upward process, the raw material continuously comes into contact with the high-temperature flue gas, and the calcium carbonate in the raw material decomposes due to heat. Finally, the raw material is discharged from the material outlet. After the gas is separated, it is sent to the cement kiln for subsequent calcination and other production processes.
[0016] In this invention, cement raw materials are initially dispersed by feeding box 5 into jacket 3. High-temperature air with a spiral upward flow is introduced into jacket 3, driving the raw materials to move. During this flow, the raw materials continuously collide with the feeding plate 7. This impact and collision further breaks down any remaining clumps in the raw materials. Finally, the raw materials are sprayed into the inner shell of the furnace through nozzle 8 along with the airflow. This process ensures that the raw materials are evenly dispersed in the airflow and distributed throughout the entire furnace space of the decomposition furnace 1, allowing for full contact with the hot airflow and avoiding the uneven distribution of raw materials seen in traditional processes, thus improving the decomposition rate. Secondly, to address the problem of harmful components such as alkali, chlorine, and sulfur accumulating on the lower inner wall of the decomposition furnace 1 and forming a hard crust on the furnace wall due to the adhesion of raw material particles, an air cannon 11 is installed. During actual operation, the air cannon 11 can be periodically activated, utilizing the powerful, instantaneous impact airflow to effectively break down the newly formed, still-weak crusts. The skin is blown off to prevent it from thickening and strengthening, ensuring smooth flow of materials and airflow within the decomposition furnace 1. This avoids blockages caused by skin formation, eliminating the need for kiln shutdown for cleaning and ensuring normal system operation. Furthermore, the jacket 3 introduces tertiary air, which is high-temperature, oxygen-rich combustion air drawn from the cement kiln grate cooler and delivered to the decomposition furnace 1. Its heat comes from the clinker discharged from the cement kiln. The tertiary air entering the jacket 3 serves three purposes: firstly, it heats the raw materials using the residual heat from the cement clinker in the grate cooler; secondly, it insulates the decomposition furnace 1, preventing heat loss and cooling around the perimeter, eliminating localized low-temperature zones, and ensuring a more uniform temperature between the center and perimeter, thus guaranteeing efficient decomposition of raw materials in the surrounding area; and thirdly, the tertiary air's power drives the flow of raw materials and provides impact, further dispersing them.
[0017] The side wall of the bulk material plate 7 is provided with multiple protrusions 12 with sharp tops. During operation, the raw material in the airflow will collide with the protrusions 12. The tops of the protrusions are relatively sharp, which can effectively break up the clumps of raw material and improve the dispersion effect of raw material in the airflow.
[0018] In order to achieve a better cleaning effect on the crust and effectively eliminate cleaning dead corners, the air cannon 11 is provided with 2 to 3 rows on the middle shell and the bottom cone respectively, and the air cannons 11 in the upper and lower adjacent rows are staggered on the circumference.
[0019] Each row of nozzles 8 is evenly distributed along the circumference of the middle shell, with adjacent rows of nozzles 8 arranged alternately. The angle between the spray direction of each row of nozzles 8 and the vertical center line gradually decreases from top to bottom. After the raw material is sprayed from the nozzles 8, it will diffuse. In this invention, the raw material sprayed from the same row of nozzles 8 diffuses and is distributed in a circular area within the decomposition furnace 1. The raw material sprayed from multiple rows of nozzles 8 can be distributed across the entire cross-section of the decomposition furnace 1. To avoid excessive overlap and superposition of raw material, each row of nozzles 8 is evenly distributed along the circumference of the middle shell, with adjacent rows of nozzles 8 arranged alternately. The angle between the spray direction of each row of nozzles 8 and the vertical center line gradually decreases from top to bottom, thereby improving the uniformity of raw material distribution within the decomposition furnace 1.
[0020] The raw material sprayed from the uppermost nozzle 8 is sprayed into the middle area of the decomposition furnace 1. The lower the nozzle 8 is, the closer the sprayed raw material is to the edge of the decomposition furnace 1. The diameter of each row of nozzles 8 gradually increases from top to bottom. In this invention, the raw material sprayed from the uppermost nozzle 8 is sprayed into the middle area of the decomposition furnace 1. The lower the nozzle 8 is, the closer the sprayed raw material is to the edge of the decomposition furnace 1. Considering that the area of the middle area of the decomposition furnace 1 is small and the area of the area closer to the edge of the decomposition furnace 1 is large, the uppermost nozzle 8 has the smallest diameter and sprays less raw material. The nozzles 8 that are lower have larger diameters and spray more raw material. This allows the raw material to be evenly distributed in various areas of the cross section of the decomposition furnace 1, thus improving the uniformity of raw material distribution.
[0021] A burner 13 is installed at the lower part of the upper shell. The upper shell is located at the top of the decomposition furnace 1. The burner 13 is installed at the top of the decomposition furnace 1 to achieve staged combustion in the decomposition furnace 1 and minimize NOx emissions. At the same time, the burner 13 installed at the top of the decomposition furnace 1 can also serve as an adjustment means to fine-tune the temperature of the material outlet at the top of the decomposition furnace 1.
Claims
1. A high-efficiency preheating and decomposition device for cement raw materials based on waste heat, comprising a decomposition furnace (1) and a material outlet disposed at the top of the decomposition furnace (1), wherein a flue gas inlet (2) is disposed at the bottom of the decomposition furnace (1), characterized in that: The decomposition furnace (1) consists of an upper shell, a middle shell, and a bottom cone connected sequentially from top to bottom. An integral jacket (3) is provided on the outer side of the middle shell and the bottom cone. The bottom of the jacket (3) is tangentially connected to a lower tertiary air duct (4). A feeding box (5) is connected above the lower tertiary air duct (4). A spiral rod (6) is provided inside the jacket (3). Several material distribution plates (7) are spaced on the spiral rod (6). Multiple rows of spray nozzles (8) are spaced vertically on the middle shell above the jacket (3). The spray direction of the spray nozzles (8) is inclined downward. Multiple coal powder spray guns (9) and upper tertiary air ducts (10) are evenly distributed along the circumference of the lower part of the middle shell. The coal powder spray guns (9) and upper tertiary air ducts (10) are staggered on the circumference. Air cannons (11) are provided on both the middle shell and the bottom cone. The nozzles of the air cannons (11) on the middle shell are arranged horizontally and tangentially. The nozzles of the air cannons (11) on the bottom cone are arranged inclined downward.
2. The efficient preheating and decomposition device for cement raw materials based on waste heat according to claim 1, characterized in that: The side wall of the bulk material plate (7) is provided with a plurality of sharp-topped protrusions (12).
3. The efficient preheating and decomposition device for cement raw materials based on waste heat according to claim 1, characterized in that: The air cannon (11) has 2 to 3 rows on the middle shell and the bottom cone respectively, and the air cannons (11) of the two adjacent rows are staggered on the circumference.
4. The efficient preheating and decomposition device for cement raw materials based on waste heat according to claim 1, characterized in that: Each row of nozzles (8) is evenly distributed along the circumference of the middle shell. The upper and lower adjacent rows of nozzles (8) are staggered. The angle between the spraying direction of each row of nozzles (8) and the vertical center line gradually decreases from top to bottom.
5. The efficient preheating and decomposition device for cement raw materials based on waste heat according to claim 4, characterized in that: The diameter of each row of spray nozzles (8) gradually increases from top to bottom.
6. The efficient preheating and decomposition device for cement raw materials based on waste heat according to claim 1, characterized in that: A burner (13) is provided at the lower part of the upper shell.