A thermal radiation calcining kiln

Abstract

This invention provides a radiant calcining kiln, belonging to the field of calcining kiln technology. It includes a feeding device for lifting materials into the kiln; a calcining kiln for calcining the materials, comprising a preheating zone for preheating the materials, a calcining zone for calcining the materials, and a cooling zone for cooling the calcined materials; and a waste gas treatment system for treating the waste gas generated during combustion. This invention can calcine small materials with a diameter less than 20mm, solving the problems of easy nodule formation, poor permeability, and low utilization rate and resource waste in the calcination of small particles. During use, nodule formation is prevented, reducing the difficulty of production operations, and the heat from combustion can be fully utilized, achieving energy conservation and emission reduction. Through radiant heat transfer, the materials do not directly contact the flame, resulting in uniform heating, a low rate of undercooked materials, and no open flame inside the kiln, thus producing less ash and resulting in higher purity clinker.

Description

Technical Field

[0001] This invention relates to the field of calcining furnace technology, and specifically to a thermal radiation calcining kiln. Background Technology

[0002] In the process of mining and mineral material processing, a large amount of unusable small-particle tailings, industrial waste, scraps, and powders are generated, such as limestone tailings, magnesite tailings, siderite, industrial gypsum, phosphate tailings, carbide slag, kaolin, sulfur concentrate, ceramsite, and sugar paste. However, due to the poor permeability of these small particles, existing calcining kilns, such as double-chamber kilns, double-C kilns, rotary kilns, beam kilns, traditional vertical kilns, and opposed-firing kilns, can only calcine materials ranging from 20mm to 100mm. These kiln types easily form nodules when calcining small materials, with the flame directly contacting the material, resulting in excessively high local temperatures. Small-diameter powdery materials are prone to melting and crystallization. Without further processing of 0-20mm undersize materials, scraps, and powders, these small particles are discarded, leading to resource waste, increased production costs, and environmental pollution. Grinding and reusing them would further increase production costs and hinder the healthy development of enterprises. The permeability of the material will also decrease after the material is attached to the lumps, which is not conducive to the recovery of carbon dioxide. Summary of the Invention

[0003] This invention provides a thermal radiation calcining kiln to solve the technical problem that existing calcining kilns are prone to lumps when calcining materials or powders with a diameter of less than 20 mm.

[0004] To solve the above problems, the thermal radiation calcining kiln provided by the present invention adopts the following technical solution: it includes a feeding device for lifting materials into the calcining kiln; a calcining kiln for calcining the materials, the calcining kiln including a preheating zone for preheating the materials, a calcining zone for calcining the materials, and a cooling zone for cooling the calcined materials; a waste gas treatment system for treating the waste gas generated by combustion; and a blower system for assisting combustion and cooling the calcined materials.

[0005] The calcining kiln is equipped with a hot air circulation chamber arranged vertically inside. The bottom of the hot air circulation chamber extends to the cooling zone, and the top of the hot air circulation chamber extends to the preheating zone. Air caps are installed at both the upper and lower ends of the hot air circulation chamber.

[0006] The calcining zone of the calcining kiln is equipped with a thermal radiation calcining cylinder. The thermal radiation calcining cylinder has a cavity, and the combustion nozzle burns in the cavity of the thermal radiation calcining cylinder, thereby avoiding direct contact between the open flame and the material. The cavity of the thermal radiation calcining cylinder is connected to the hot gas circulation cavity, so that the exhaust gas generated by combustion enters the preheating zone through the hot gas circulation cavity.

[0007] By adopting the above technical solution, the problem of existing calcining kilns' inability to handle small particles with a diameter of less than 20mm is solved. Research and observation revealed that the main reason for the nodulation of small particles is the excessively high local temperature within the calcining kiln, causing the small particles to easily melt and form nodules. Taking a vertical kiln as an example, the material in the calcining zone remains stationary for extended periods, while the position of the combustion nozzle does not change. This results in the flame heating one area for a prolonged period, leading to excessively high local temperatures and the formation of nodules from small particles. This invention addresses this issue by installing a thermal radiation calcining cylinder in the calcining zone. The combustion nozzle burns within the cavity of the thermal radiation calcining cylinder, heating the material through thermal radiation. This avoids direct contact between the flame and the material, resulting in uniform heating throughout the calcining zone and a lower rate of undercooked material. This solves the problem of nodulation in existing calcining kilns when calcining materials with a diameter less than 20mm, reducing resource waste and lowering production costs for enterprises.

[0008] As a further improvement, the air cap at the bottom of the hot gas circulation chamber is a cooling air cap, and the air cap at the top of the hot gas circulation chamber is a preheating air cap. The blower system is connected to the cooling air cap through a pipe. The cold air carries away the heat of the cooling zone, so that the calcined material is cooled quickly, and the exhaust gas after combustion is also transported to the preheating zone.

[0009] By adopting the above technical solution, on the one hand, the materials in the preheating zone can be preheated more effectively, and on the other hand, dust can be reduced. The hot air circulation chamber can directly transport exhaust gas to the preheating zone, utilizing the residual heat of the exhaust gas to preheat the materials. The cold air at the bottom of the hot air circulation chamber not only cools the chamber but also facilitates the upward transport of exhaust gas. In the past, the combustion nozzle was in direct contact with the materials, causing the exhaust gas generated by combustion to carry dust from the materials upwards. Dust treatment equipment needed to handle a large amount of dust, resulting in frequent maintenance and replacement of the equipment, which impacted production.

[0010] As a further improvement, the thermal radiation calcining cylinder is provided with a thermal radiation calcining cylinder protective cover for protecting the thermal radiation calcining cylinder. The thermal radiation calcining cylinder protective cover has a cavity. One end of the thermal radiation calcining cylinder protective cover is connected to the blower system, and the other end of the thermal radiation calcining cylinder protective cover is connected to the preheating zone through a pipe. The cold air blown out by the blower system passes through the cavity of the thermal radiation calcining cylinder protective cover to cool the thermal radiation calcining cylinder protective cover. The heated gas is discharged from the preheating zone to preheat the material.

[0011] By adopting the above technical solution, the thermal radiation calcining cylinder is protected. The protection of the thermal radiation calcining cylinder protective cover is divided into two parts: first, to prevent materials from falling and damaging the thermal radiation calcining cylinder; and second, to cool down and prevent the temperature of the thermal radiation calcining cylinder from becoming too high. After the cold air blown in cools the thermal radiation calcining cylinder protective cover and its surroundings, the cold air is heated and discharged from the preheating zone to preheat the materials and make full use of the residual heat.

[0012] As a further improvement, the exhaust gas treatment system includes a dust treatment device for treating dust and a carbon dioxide treatment device for recovering carbon dioxide.

[0013] By adopting the above technical solutions, the impact on the environment is reduced. The dust treatment equipment mainly treats the dust in the exhaust gas, and the carbon dioxide treatment equipment recovers the carbon dioxide generated during calcination to reduce carbon emissions.

[0014] As a further improvement, the dust treatment equipment includes a dust removal device, the air inlet pipe of which is connected to the top of the calcining kiln, and the air outlet of which is connected to the chimney via a pipe.

[0015] By adopting the above technical solution, the dust removal equipment is used to treat dust particles, avoiding the impact on the surrounding environment, and the treated gas is discharged through a chimney.

[0016] As a further improvement, the carbon dioxide treatment equipment includes a carbon dioxide recovery device for recovering carbon dioxide, the inlet of which is connected to the top of the calcining kiln via a pipe, and the outlet of which is connected to a carbon dioxide storage device.

[0017] By adopting the above technical solution, carbon dioxide recovery and utilization are achieved. The carbon dioxide recovery device recovers the carbon dioxide generated during calcination, and the carbon dioxide storage device stores the recovered carbon dioxide. This reduces carbon emissions while allowing carbon dioxide to be recycled and reused, which is beneficial to the healthy development of enterprises.

[0018] As a further improvement, the bottom of the calcining kiln is provided with a conveyor belt for conveying materials, and the end of the conveyor belt is also provided with an elevator for lifting materials.

[0019] By adopting the above technical solution, the conveyor belt and elevator transport the calcined material to the finished product warehouse for subsequent processing.

[0020] As a further improvement, the blower system is connected to the combustion nozzle via a pipe to mix air with the combustion gas.

[0021] By adopting the above technical solution, it is beneficial to the complete combustion of gas.

[0022] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0023] 1. Compared to other existing kiln designs, this kiln can calcine materials with a diameter of less than 20mm, solving the problem of resource waste caused by small particle nodules and reducing environmental pollution. Furthermore, since no small particles are generated, there is no need for recycling and grinding, thus reducing production costs for enterprises. During operation, no nodules are generated, simplifying production processes and ensuring full utilization of combustion heat, achieving energy conservation and emission reduction.

[0024] 2. The present invention incorporates a thermal radiation calcining cylinder in the calcining zone. Through radiation heat transfer, the material does not directly contact the flame, resulting in uniform heating, a low rate of undercooked material, and no open flame inside the kiln, thus preventing the generation of excessive ash and resulting in high purity of the calcined clinker. Furthermore, the residual heat generated during the calcination process is fully utilized. Attached Figure Description

[0025] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0026] Figure 1 This is an overall structural diagram of the thermal radiation calcining kiln of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the thermal radiation calcining kiln of the present invention;

[0028] Figure 3 This is a partial schematic diagram of the thermal radiation calcining kiln of the present invention;

[0029] Figure 4 for Figure 3 Enlarged view of part A.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Finished ash conveyor belt; 2. Cooling hood; 3. Combustion nozzle; 4. Thermal radiation calcining cylinder; 5. Thermal radiation calcining cylinder protective cover; 6. Hot gas circulation chamber; 7. Hot gas circulation pipe; 8. Preheating hood; 9. Refractory lining; 10. Material feed transition bin; 11. Chimney; 12. Finished product bin; 13. Dust removal equipment; 14. Carbon dioxide recovery device; 15. Carbon dioxide storage device; 16. Gas pressurization station; 17. Cooling fan; 18. Feeding belt; 19. Material transition bin; 20. Material conveyor belt; 21. Material shed. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] To address the problem of clumping in existing calcining kilns when calcining small materials with a diameter of less than 20mm, this invention incorporates a thermal radiation calcining cylinder within the calcining zone. The combustion nozzles are positioned within the cavity of this cylinder, preventing direct flame contact with the material. Heating the material via thermal radiation avoids localized overheating, thus preventing clumping of smaller material particles or powders due to excessively high temperatures. This results in more uniform heating of the material and reduces the likelihood of undercooked materials.

[0034] When constructing the hot gas circulation chamber, a hole is reserved for connection with the thermal radiation calcination cylinder, allowing the hot gas circulation chamber to communicate with the thermal radiation calcination cylinder. This design allows the exhaust gas to be directly discharged to the preheating zone, avoiding poor gas flow that could affect the preheating effect. Furthermore, it significantly reduces dust generation. Previously, dust in the material would float upwards with the exhaust gas from combustion; with the improved design, the combustion exhaust gas is directly discharged into the preheating zone, drastically reducing dust generation.

[0035] The protective cover for the thermal radiation calcining cylinder is mainly used to reduce the temperature around the thermal radiation calcining cylinder, prevent the temperature of the thermal radiation calcining cylinder from becoming too high, and at the same time, the heat carried away is discharged from the preheating zone to preheat the material and make full use of the waste heat.

[0036] For the exhaust gas produced by combustion, the carbon dioxide recovery device recovers and stores the carbon dioxide in the exhaust gas to reduce carbon emissions. The main source of pollution in the remaining exhaust gas is dust, which can be discharged through the chimney after being purified by dust removal equipment.

[0037] After introducing the basic principles of the present invention, various non-limiting embodiments of the present invention are described in detail below. Any number of elements in the accompanying drawings is for illustrative purposes only and not for limitation, and any naming is for distinction only and has no limiting meaning.

[0038] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0039] Example 1 of the thermal radiation calcining kiln provided by the present invention:

[0040] like Figures 1-4As shown, it includes a feeding device for lifting materials to the calcining kiln. In this embodiment, the feeding device includes a material conveyor belt 20, which transports materials from the material shed 21 to the material transition bin. During feeding, the materials are lifted and fed by the feeding belt 18.

[0041] The calcining kiln is a vertical kiln used for calcining materials. The calcining kiln includes a preheating zone for preheating the materials, a calcining zone for calcining the materials, and a cooling zone for cooling the calcined materials. The top of the calcining kiln is provided with a material inlet passage 10 for temporarily storing materials. The side walls of the calcining kiln are lined with refractory linings 9.

[0042] The exhaust gas treatment system treats the exhaust gases generated during combustion.

[0043] The blower system is used to assist combustion and cool the calcined material. The blower system consists of several cooling fans 17.

[0044] The calcining kiln is equipped with a hot air circulation chamber 6 arranged vertically. The bottom of the hot air circulation chamber 6 extends to the cooling zone, and the top of the hot air circulation chamber 6 extends to the preheating zone. Both the upper and lower ends of the hot air circulation chamber 6 are equipped with air caps.

[0045] The calcining belt of the calcining kiln is equipped with multiple thermal radiation calcining cylinders 4, which are arranged vertically on the calcining belt. Each thermal radiation calcining cylinder 4 has a cavity, and the combustion nozzle 3 burns in the cavity of the thermal radiation calcining cylinder 4, thereby avoiding direct contact between the open flame and the material. The combustion nozzle 3 is connected to the gas pressurization station 16. The cavity of the thermal radiation calcining cylinder 4 is connected to the hot gas circulation chamber 6, so that the exhaust gas generated by combustion enters the preheating zone through the hot gas circulation chamber 6.

[0046] By adopting the above technical solution, the problem of existing calcining kilns' inability to handle small particles with a diameter of less than 20mm is solved. Research and observation revealed that the main reason for the nodulation of small particles is the excessively high local temperature within the calcining kiln, causing the small particles to easily melt and form nodules. Taking a vertical kiln as an example, the material in the calcining zone remains stationary for extended periods, while the position of the combustion nozzle 3 does not change. This results in the flame heating one area for a prolonged period, leading to excessively high local temperatures and the formation of nodules from small particles. This invention addresses this issue by installing a thermal radiation calcining cylinder 4 in the calcining zone. The combustion nozzle 3 burns within the cavity of the thermal radiation calcining cylinder 4, heating the material through thermal radiation. This avoids direct contact between the flame and the material, resulting in uniform heating throughout the calcining zone and a lower rate of undercooked material. This solves the problem of nodulation in existing calcining kilns when calcining materials with a diameter less than 20mm, reducing resource waste and lowering production costs for enterprises.

[0047] like Figure 2-4As shown, the air cap at the bottom of the hot air circulation chamber 6 is the cooling air cap 2, and the air cap at the top of the hot air circulation chamber 6 is the preheating air cap 8. The blower system is connected to the cooling air cap 2 through a pipe. The cold air carries away the heat of the cooling zone, so that the calcined material is cooled quickly, and the exhaust gas after combustion is also transported to the preheating zone.

[0048] By adopting the above technical solution, the materials in the preheating zone can be preheated more effectively, and dust levels can be reduced. The hot air circulation chamber 6 can directly transport exhaust gas to the preheating zone, utilizing the residual heat of the exhaust gas to preheat the materials. The cold air at the bottom of the hot air circulation chamber 6 not only cools the chamber but also facilitates the upward transport of exhaust gas. Previously, the combustion nozzle 3 was in direct contact with the materials, causing the exhaust gas generated during combustion to carry dust from the materials upwards. This required the dust treatment equipment to handle a large amount of dust, resulting in frequent maintenance and replacement of the equipment, which impacted production.

[0049] like Figure 2-4 As shown, the thermal radiation calcining cylinder 4 is equipped with a thermal radiation calcining cylinder protective cover 5 for protecting the thermal radiation calcining cylinder 4. The thermal radiation calcining cylinder protective cover 5 has a cavity. One end of the thermal radiation calcining cylinder protective cover 5 is connected to the blower system, and the other end of the thermal radiation calcining cylinder protective cover 5 is connected to the preheating zone through a pipe. The cold air blown out by the blower system passes through the cavity of the thermal radiation calcining cylinder protective cover 5 to cool the thermal radiation calcining cylinder protective cover 5. The heated gas is discharged from the preheating zone to preheat the material.

[0050] By adopting the above technical solution, the thermal radiation calcining cylinder 4 is protected. The protection of the thermal radiation calcining cylinder protective cover 5 is divided into two parts: first, to prevent the material from falling and damaging the thermal radiation calcining cylinder 4; and second, to cool down and prevent the temperature of the thermal radiation calcining cylinder 4 from becoming too high. After the cold air blown in cools the thermal radiation calcining cylinder protective cover 5 and its surroundings, the cold air is heated and discharged from the preheating zone to preheat the material and make full use of the residual heat.

[0051] like Figure 1 As shown, the exhaust gas treatment system includes dust treatment equipment for treating dust and carbon dioxide treatment equipment for recovering carbon dioxide.

[0052] By adopting the above technical solutions, the impact on the environment is reduced. The dust treatment equipment mainly treats the dust in the exhaust gas, and the carbon dioxide treatment equipment recovers the carbon dioxide generated during calcination to reduce carbon emissions.

[0053] In this embodiment, the dust treatment equipment includes a dust removal device 13. The air inlet pipe of the dust removal device 13 is connected to the top of the calcining kiln, and the air outlet of the dust removal device 13 is connected to the chimney 11 through a pipe.

[0054] By adopting the above technical solution, the dust removal equipment 13 is used to treat dust particles to avoid impacting the surrounding environment, and the treated gas is discharged through the chimney 11.

[0055] In this embodiment, the carbon dioxide treatment equipment includes a carbon dioxide recovery device 14 for recovering carbon dioxide. The inlet of the carbon dioxide recovery device 14 is connected to the top of the calcining kiln through a pipe, and the outlet of the carbon dioxide recovery device 14 is connected to a carbon dioxide storage device 15. Both the carbon dioxide recovery device 14 and the carbon dioxide storage device 15 are existing technologies and will not be described in detail here.

[0056] By adopting the above technical solution, carbon dioxide recovery and utilization are realized. The carbon dioxide recovery device 14 recovers the carbon dioxide generated during calcination, and the carbon dioxide storage device 15 stores the recovered carbon dioxide. While reducing carbon emissions, carbon dioxide can be recycled and reused, which is conducive to the healthy development of enterprises.

[0057] In this embodiment, a conveyor belt for transporting materials is provided at the bottom of the calcining kiln, and an elevator for lifting materials is provided at the end of the conveyor belt. The conveyor belt and elevator transport the calcined materials to the finished product bin 12 for subsequent processing.

[0058] In this embodiment, the blower system is connected to the combustion nozzle 3 through a pipe to mix air and gas, which is conducive to the complete combustion of gas.

[0059] Example 2 of the thermal radiation calcining kiln provided by the present invention:

[0060] Its main difference from Example 1 is:

[0061] In Example 1, there are multiple thermal radiation calcination cylinders, which are arranged vertically on the calcination belt.

[0062] In this embodiment, the thermal radiation calcining cylinder is a cylindrical integral unit, which has a combustion nozzle cavity and a cooling cavity, respectively replacing the thermal radiation calcining cylinder and the thermal radiation calcining cylinder protective cover.

[0063] While various embodiments of the invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of the invention and therefore cover any modular compositions, equivalents, or alternatives within the scope of these claims.

Claims

1. A thermal radiation calcining kiln, comprising: The feeding device is used to lift the material into the calcining kiln; A calcining kiln is used to calcine materials. A calcining kiln includes a preheating zone for preheating the materials, a calcining zone for calcining the materials, and a cooling zone for cooling the calcined materials. The exhaust gas treatment system treats the exhaust gases generated during combustion. The blower system is used to aid combustion and cool the calcined material. The characteristic feature is that the calcining kiln is provided with a hot air circulation chamber (6) arranged in a vertical direction inside, the bottom of the hot air circulation chamber (6) extends to the cooling zone, the top of the hot air circulation chamber (6) extends to the preheating zone, and wind caps are installed at both the upper and lower ends of the hot air circulation chamber (6). The calcining zone of the calcining kiln is equipped with a thermal radiation calcining cylinder (4). The thermal radiation calcining cylinder (4) has a cavity. The combustion nozzle (3) burns in the cavity of the thermal radiation calcining cylinder (4), thereby avoiding direct contact between the open flame and the material. The cavity of the thermal radiation calcining cylinder (4) is connected to the hot gas circulation chamber (6), so that the exhaust gas generated by combustion enters the preheating zone through the hot gas circulation chamber (6). The thermal radiation calcining cylinder (4) is provided with a thermal radiation calcining cylinder protective cover (5) for protecting the thermal radiation calcining cylinder (4). The thermal radiation calcining cylinder protective cover (5) has a cavity. One end of the thermal radiation calcining cylinder protective cover (5) is connected to the blower system, and the other end of the thermal radiation calcining cylinder protective cover (5) is connected to the preheating zone through a pipe. The cold air blown out by the blower system passes through the cavity of the thermal radiation calcining cylinder protective cover (5) to cool the thermal radiation calcining cylinder protective cover (5). The heated gas is discharged from the preheating zone to preheat the material.

2. The thermal radiation calcining kiln according to claim 1, characterized in that: The bottom of the hot air circulation chamber (6) is a cooling air cap (2), and the top of the hot air circulation chamber (6) is a preheating air cap (8). The blower system is connected to the cooling air cap (2) through a pipe. The cold air carries away the heat of the cooling zone, so that the calcined material is cooled quickly, and the exhaust gas after combustion is transported to the preheating zone.

3. The thermal radiation calcining kiln according to claim 1, characterized in that: The exhaust gas treatment system includes dust treatment equipment for treating dust and carbon dioxide treatment equipment for recovering carbon dioxide.

4. The thermal radiation calcining kiln according to claim 3, characterized in that: The dust treatment equipment includes a dust removal device (13), the air inlet pipe of which is connected to the top of the calcining kiln, and the air outlet of which is connected to the chimney (11) through a pipe.

5. The thermal radiation calcining kiln according to claim 3, characterized in that: The carbon dioxide treatment equipment includes a carbon dioxide recovery device (14) for recovering carbon dioxide. The inlet of the carbon dioxide recovery device (14) is connected to the top of the calcining kiln through a pipe, and the outlet of the carbon dioxide recovery device (14) is connected to a carbon dioxide storage device (15).

6. The thermal radiation calcining kiln according to claim 1, characterized in that: The bottom of the calcining kiln is equipped with a conveyor belt for transporting materials, and the end of the conveyor belt is also equipped with an elevator for lifting materials.

7. The thermal radiation calcining kiln according to claim 1, characterized in that: The blower system is connected to the combustion nozzle (3) via a pipe to mix air and gas.

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