Clay calcination treatment system

Abstract

The present disclosure relates to a clay calcination treatment system, comprising a raw material mill, a dust collector connected to an outlet of the raw material mill, a calcination preheating system and a flue gas exhaust system which are connected to an outlet of the dust collector, a cooling system connected to an outlet of the calcination preheating system, and an exhaust gas harmless treatment system used for treating an inert gas, wherein the calcination preheating system comprises a preheating cyclone, a decomposition furnace, a first hot blast stove used for providing a heat source for the decomposition furnace, and a second fan; the cooling system comprises a cooling cyclone; and the exhaust gas harmless treatment system comprises a third fan and a second hot blast stove. An inert exhaust gas generated in the decomposition furnace passes through the preheating cyclone and then enters the second hot blast stove, and an outlet of the second hot blast stove is connected to the raw material mill. CO, volatile matter and sulfide in the inert exhaust gas are digested and absorbed inside the system, thereby reducing air pollution; a reducing atmosphere is maintained during a calcining process, such that the color of a finished product is ensured; and the clay calcination treatment system can perfectly adapt to a high-humidity clay calcining process, and can significantly reduce the treatment investment cost of the inert exhaust gas, and the inert exhaust gas can also meet gaseous emission standards.

Description

Clay calcination processing system Technical Field

[0001] The present disclosure relates to the field of calcining technology, and in particular to a clay calcining processing system. Background Art

[0002] Due to its inherent characteristics, clay calcination technology does not produce carbon dioxide itself during calcination; only the fuel forms waste gas. This can reduce CO2 emissions by 40% compared to conventional cement clinker, leading to its increasing promotion and application. However, due to the diversity of clay, it contains a large number of elements, especially iron, which oxidizes to a red color during combustion, unlike traditional cement ash. Therefore, the production process must be controlled to ensure the product is gray-black. Furthermore, clay contains various harmful components that are emitted into the atmosphere during high-temperature processing and require processing. Therefore, how to control product color and economically treat waste gas emissions during the production process is a key and difficult issue in this field of research. Summary of the Invention

[0003] In order to control the product color during the clay calcining process and economically treat the waste gas generated during the process, the present disclosure provides a clay calcining treatment system.

[0004] The present disclosure provides a clay calcination treatment system that adopts the following technical solutions:

[0005] A clay calcining and processing system comprises a raw material mill, a dust collector connected to the outlet of the raw material mill, a calcining preheating system and a smoke exhaust system connected to the outlet of the dust collector, a cooling system connected to the outlet of the calcining preheating system, a waste gas harmless treatment system for treating inert gas, and a waste gas recycling system; the calcining preheating system comprises a preheating cyclone, a decomposition furnace, a first hot blast furnace for providing a heat source to the decomposition furnace, and a second fan; the cooling system comprises a cooling cyclone, and the waste gas harmless treatment system comprises a third fan and a second hot blast furnace; the waste gas recycling system comprises a first heat exchanger and a fourth fan; the inert waste gas generated in the decomposition furnace passes through a multi-stage preheating cyclone, a first heat exchanger, a fourth fan, and cooling cyclones located at the first few stages, and is then input into the second hot blast furnace through the third fan, and the outlet of the second hot blast furnace is connected to the raw material mill.

[0006] By adopting the above technical solution, CO, volatile organic compounds and sulfides in the inert waste gas are treated by the second hot blast furnace and raw material dust, so that the discharged waste gas meets the standards; by creatively utilizing the characteristics of the raw materials and controlling the oxygen input in the decomposition furnace to be lower than the amount required for combustion, the entire combustion process maintains a reducing atmosphere, ensuring that the finished product is gray-black; the entire clay calcination treatment system has low pressure loss, reduced system heat consumption, and meets the emission standards, which can significantly reduce the treatment cost and save optimization investment; the inert waste gas is cooled by the first heat exchanger and then transported to the first few stages of cooling cyclones for cooling. On the one hand, it can reduce the sulfide content in the inert waste gas, and on the other hand, it can realize the recycling of the inert waste gas, reduce the consumption of external clean air, and realize economic value.

[0007] Optionally, cold air is introduced into the cooling cyclones located in the latter stages, and the gas output from the heat exchange enters the first hot air furnace through the second fan.

[0008] By adopting the above technical solution, the cold air can be used for the cooling process of the cooling system, and the gas after heat exchange can be transported to the first hot blast furnace for recycling, thereby improving economy.

[0009] Optionally, the third fan is provided with two branches for outputting the inert gas, the first branch is connected to the second hot blast furnace, the second branch is connected to the cooling cyclones located in the first few stages, and a second heat exchanger is installed on the second branch.

[0010] By adopting the above technical solution and adding a branch with a second heat exchanger, the shortage of inert gas can be effectively compensated, so that sufficient inert gas can be introduced into the cooling system for cooling, thereby achieving higher economic value.

[0011] Optionally, the second heat exchanger is equipped with a fifth fan, and the heat exchange gas output by the second heat exchanger is transported to the raw material mill.

[0012] By adopting the above technical solution, the heat exchange air is connected to the entire system, achieving the airtightness of the entire system.

[0013] Optionally, two branches are provided for the output gas from the second hot blast furnace, the first branch is connected to the raw material mill, and the second branch is connected to the dust collector.

[0014] By adopting the above technical solution, if the moisture content of the clay is reduced, part of the high-temperature gas can be directly input into the dust collector to meet the diversified usage requirements according to the moisture content of the clay.

[0015] Optionally, the smoke exhaust system includes a first fan and a smoke exhaust tower.

[0016] By adopting the above technical solution, the effective discharge of exhaust gas is achieved.

[0017] Optionally, the finished product output end of the cooling system is provided with a conveying reamer for conveying the finished product to the storage system.

[0018] By adopting the above technical solution, the effective output of finished products is achieved.

[0019] Optionally, the clay in the stockpile is transported to the raw mill via a conveyor belt.

[0020] By adopting the above technical solution, effective input of clay is achieved.

[0021] In summary, the present disclosure includes at least one of the following beneficial technical effects:

[0022] The CO, volatile organic compounds, and sulfides in the inert exhaust gas are treated by the second hot blast furnace and raw material dust, ensuring that the exhaust gas meets standards. By creatively utilizing the characteristics of the raw materials and controlling the oxygen input into the decomposition furnace to be lower than the amount required for combustion, a reducing atmosphere is maintained throughout the combustion process, ensuring that the finished product is gray-black. The entire clay calcination treatment system has low pressure loss, reduced system heat consumption, and meets exhaust gas standards, significantly reducing treatment costs and optimizing investment.

[0023] After being cooled by the first heat exchanger, the inert waste gas is transported to the first few stages of cooling cyclones for cooling. This can reduce the sulfide content in the inert waste gas and, on the other hand, achieve recycling of the inert waste gas, reduce the consumption of clean air from the outside, and realize economic value.

[0024] Adding a branch with a second heat exchanger can effectively compensate for the shortage of inert gas, allowing sufficient inert gas to flow into the cooling system for cooling, thereby achieving higher economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a clay calcining treatment system according to an embodiment of the present disclosure.

[0026] Explanation of the accompanying drawings: 1. Raw material mill; 10. Conveyor belt; 2. Dust collector; 20. First fan; 21. Smoke exhaust tower; 3. Calcination preheating system; 30. First preheating cyclone; 31. Second preheating cyclone; 32. Decomposition furnace; 33. First hot blast furnace; 34. Second fan; 35. Third preheating cyclone; 4. Cooling system; 40. First cooling cyclone; 41. Second cooling cyclone; 42. Third cooling cyclone; 43. Fourth cooling cyclone; 5. Conveying reamer; 6. Waste gas harmless treatment system; 60. Third fan; 61. Second hot blast furnace; 7. Waste gas recycling system; 70. First heat exchanger; 71. Fourth fan; 72. Second heat exchanger; 73. Fifth fan. DETAILED DESCRIPTION

[0027] The present disclosure is further described in detail below with reference to FIG1 .

[0028] This embodiment discloses a clay calcination processing system. Referring to Figure 1 , the clay calcination processing system includes a raw material mill 1, a dust collector 2, a calcination preheating system 3, a cooling system 4, a conveying reamer 5, an exhaust gas harmless treatment system 6, and an exhaust gas recycling system 7. This system is particularly suitable for processing clay with a high moisture content and iron content exceeding 20%.

[0029] Referring to Figure 1, clay is transported from the stockpile via a conveyor belt 10 to the raw material mill 1 for drying and grinding. A dust collector 2 is connected to the raw material mill 1 to separate the finished product from the exhaust gas after grinding. The finished product is fed into the calcination and preheating system 3, and the exhaust gas is discharged through the smoke exhaust system. The calcination and preheating system 3 includes a primary preheating cyclone 30, a secondary preheating cyclone 31, a decomposition furnace 32, a first hot blast furnace 33, a second blower 34, and a tertiary preheating cyclone 35. There are two primary preheating cyclones 30. The finished product output from the dust collector 2 is first fed into the two primary preheating cyclones 30 for heating, then enters the secondary preheating cyclone 31 for further heating, and then enters the decomposition furnace 32 for high-temperature calcination and dehydroxylation.

[0030] Referring to Figure 1 , to prevent iron oxidation at high temperatures, a reducing atmosphere is maintained within the decomposition furnace 32. The air supply to the fuel during combustion is controlled to be less than the amount required for complete fuel combustion. This creates a reducing atmosphere of CO and H2 within the decomposition furnace 32. At high temperatures, Fe2O3 is reduced to Fe3O4, maintaining the finished product's grayish-black color. However, volatile organic compounds and sulfides are also generated. The heat source for the decomposition furnace 32 is provided by a first hot blast furnace 33, which is connected to a second air blower 34 for gas delivery. The calcined product is ultimately collected in a three-stage preheating cyclone 35.

[0031] Referring to Figure 1 , cooling system 4 is connected to calcination preheating system 3 and serves as the next step in cooling the high-temperature finished product. Cooling system 4 includes a primary cooling cyclone 40, a secondary cooling cyclone 41, a tertiary cooling cyclone 42, and a quaternary cooling cyclone 43. The high-temperature finished product, discharged from the tertiary preheating cyclone 35, is first fed into the primary cooling cyclone 40 and then sequentially into the secondary cooling cyclone 41, the tertiary cooling cyclone 42, and the quaternary cooling cyclone 43 for progressive cooling. The cooled finished product is ultimately delivered to the storage system via a conveyor reamer 5.

[0032] 1 , the waste gas harmless treatment system 6 and the waste gas recycling system 7 cooperate with each other. The waste gas harmless treatment system 6 includes a third fan 60 and a second hot air furnace 61, and the waste gas recycling system 7 includes a first heat exchanger 70, a fourth fan 71, a second heat exchanger 72, and a fifth fan 73.

[0033] Referring to Figure 1 , the cold air from the cooling system 4 sequentially enters the fourth-stage cooling cyclone 43 and the third-stage cooling cyclone 42. The gas reaches a temperature of 220°C. This gas is then fed through the second blower 34 into the first hot blast furnace 33 for recycling and combustion. The inert waste gas from the decomposition furnace 32 reaches a temperature of 850°C and contains very low oxygen. The inert waste gas from the calcination preheating system 3 contains less than 0.5% oxygen. The inert waste gas then passes through the third-stage preheating cyclone 35, the second-stage preheating cyclone 31, and the first-stage preheating cyclone 30 to preheat the finished product.

[0034] Referring to Figure 1 , the temperature of the inert exhaust gas after exiting the primary preheating cyclone 30 drops to 250°C. The inert exhaust gas then enters the first heat exchanger 70 and the fourth fan 71, where its output temperature further drops to 120°C. The inert exhaust gas is then fed into the secondary cooling cyclone 41 to rapidly cool the finished product, ensuring that the finished product is not oxidized during the cooling process and maintains its magnetized form. The temperature of the inert exhaust gas after exiting the secondary cooling cyclone 41 rises to 260°C. The inert exhaust gas is then fed into the primary cooling cyclone 40, where its temperature rises further to 490°C. The entire cooling system 4 also requires high system sealing to ensure that the oxygen content of the inert exhaust gas exiting the primary cooling cyclone 40 is less than 2%, and that some volatile organic compounds in the inert gas are removed by the high-temperature finished product.

[0035] Referring to Figure 1 , the inert exhaust gas is now transported by the third blower 60 to the second hot blast furnace 61 for high-temperature treatment. The treated gas, after exiting the second hot blast furnace 61, is heated to 850°C and used as a drying heat source for the raw material mill 1. The temperature of the second hot blast furnace 61 is adjusted adaptively based on the clay moisture content, with the two being positively correlated. The second hot blast furnace 61 converts the inert exhaust gas into the heat required for clay drying, which is then fed to the raw material mill 1. Furthermore, the second hot blast furnace 61 heats up the inert exhaust gas to eliminate CO and volatile organic compounds (VOCs), thus minimizing air pollution. This eliminates the need for a separate RTO (regenerative thermal oxidation) system to eliminate organic matter, saving processing costs.

[0036] Referring to Figure 1 , the treated gas still contains sulfides. These sulfides are adsorbed by the raw material dust as they pass through the raw material mill 1 and dust collector 2 and re-enter the system, ensuring that the treated gas meets emission standards. The gas is ultimately discharged into the atmosphere through the exhaust system consisting of the first blower 20 and the exhaust tower 21. If the clay has a low moisture content, a large amount of high-temperature gas is not required. A separate branch line can be used to directly deliver part of the gas output from the second hot blast furnace 61 to the dust collector 2.

[0037] Referring to Figure 1 , to compensate for the insufficient exhaust gas output by the calcination preheating system 3, a second heat exchanger 72 and a fifth fan 73 are provided in this embodiment. The inert exhaust gas output by the third fan 60 is split into two branches, one of which is introduced into the second hot blast furnace 61 and the other into the second heat exchanger 72. The fifth fan 73 acts on the second heat exchanger 72 for heat exchange, cooling the inert exhaust gas output by the second heat exchanger 72 to 120°C. This portion of inert exhaust gas then merges with the inert exhaust gas output by the fourth fan 71 and enters the secondary cooling cyclone 41. The heat exchanged gas is then heated to 260°C and fed into the raw material mill 1 together with the gas output by the second hot blast furnace 61.

[0038] In this clay calcination treatment system, CO, volatile organic compounds, and sulfides in the inert waste gas are digested and absorbed within the system, reducing atmospheric pollution. During the clay calcination process, organic matter contained in the raw materials volatilizes during the preheating process. To control color, a reducing atmosphere is required throughout the calcination process. The inert waste gas output from the calcination preheating system 3 contains a large amount of CO, and the fuel contains a large amount of sulfur. Separately treating these inert waste gases would be costly. This system is perfectly suited to the high-humidity clay calcination process, significantly reducing the investment cost of treating the inert waste gas while meeting gas emission standards.

[0039] The entire clay calcining system has low pressure drop and reduces system heat consumption. The finished product after calcining can partially replace traditional cement clinker, achieving the goal of energy conservation and emission reduction. This system creatively combines the control requirements of the entire clay calcining process, utilizing the characteristics of the raw materials to save and optimize investment.

[0040] The above are all preferred embodiments of the present disclosure, and are not intended to limit the protection scope of the present disclosure. Therefore, any equivalent changes made based on the structure, shape, and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A clay calcining treatment system, characterized in that: The invention comprises a raw material mill (1), a dust collector (2) connected to the outlet of the raw material mill (1), a calcination preheating system (3) and a smoke exhaust system connected to the outlet of the dust collector (2), a cooling system (4) connected to the outlet of the calcination preheating system (3), a waste gas harmless treatment system (6) for treating inert gas, and a waste gas recycling system (7); the calcination preheating system (3) comprises a preheating cyclone, a decomposition furnace (32), a first hot blast furnace (33) for providing a heat source to the decomposition furnace (32), and a second fan (34); the cooling system (4) comprises a cooling cyclone, the waste gas harmless treatment system (6) comprises a third fan (60) and a second hot blast furnace (61); and the waste gas recycling system (7) comprises a first heat exchanger (70). and a fourth fan (71); the inert exhaust gas generated in the decomposition furnace (32) passes through a multi-stage preheating cyclone, a first heat exchanger (70), a fourth fan (71), and a cooling cyclone located at the first stage, and is then input into the second hot blast furnace (61) through the third fan (60), and the outlet of the second hot blast furnace (61) is connected to the raw material mill (1); the third fan (60) is provided with two branches for outputting the inert gas, the first branch being connected to the second hot blast furnace (61), and the second branch being connected to the cooling cyclone located at the first stage, and the second branch being installed with a second heat exchanger (72); the second heat exchanger (72) is equipped with a fifth fan (73), and the heat exchange gas output by the second heat exchanger (72) is transported to the raw material mill (1).

2. The clay calcining treatment system according to claim 1, characterized in that: Cold air is introduced into the cooling cyclones at the latter stages, and the gas output from the heat exchange enters the first hot air furnace (33) through the second fan (34).

3. The clay calcining treatment system according to claim 1 or 2, characterized in that: The second hot blast furnace (61) is provided with two branches for outputting gas, the first branch being connected to the raw material mill (1), and the second branch being connected to the dust collector (2).

4. The clay calcining treatment system according to claim 1, characterized in that: The smoke exhaust system includes a first fan (20) and a smoke exhaust tower (21).

5. The clay calcining processing system according to claim 1, characterized in that: The finished product output end of the cooling system (4) is provided with a conveying reamer (5) for conveying the finished product to the storage system.

6. The clay calcining processing system according to claim 1, characterized in that: The clay in the pile is transported to the raw material mill (1) via a conveyor belt (10).

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