Rotary kiln

Abstract

The utility model provides a rotary kiln which comprises a rotary kiln cylinder, one end of the rotary kiln cylinder in the length direction is a feeding end, the other end of the rotary kiln cylinder in the length direction is a discharging end, and a containing cavity is formed in the rotary kiln cylinder. The oxygen-enriched air conveying pipe is arranged in the containing cavity, a gas conveying pipeline is formed in the oxygen-enriched air conveying pipe, the gas conveying pipeline is suitable for conveying oxygen-enriched air into the containing cavity, and a plurality of first nozzles are formed in the oxygen-enriched air conveying pipe; and the pulverized coal conveying pipe is arranged in the containing cavity, a pulverized coal conveying pipeline is formed in the pulverized coal conveying pipe, and a plurality of second nozzles are formed in the pulverized coal conveying pipe. Therefore, net calorific value of coal is increased, coal consumption is reduced, production cost is reduced, and smoke amount is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of rotary kilns, in particular to a rotary kiln. Background Art

[0002] Rotary kiln iron reduction is a method of reducing iron ore into metallic iron in a rotary kiln by a reducing agent. This method plays an important role in the steel industry because it can effectively extract iron from iron ore. Iron ore is reduced by a reducing agent (such as coal or natural gas) in a rotary kiln, and iron oxide is reduced to metallic iron. This process is usually carried out at a temperature of 950℃ to 1100℃. The rotary kiln in the related art has high coal consumption and large flue gas volume during the process of reducing iron ore. Therefore, the current rotary kiln needs further improvement. Utility Model Content

[0003] The utility model aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] The utility model proposes a rotary kiln, which comprises: a rotary kiln cylinder, one end of the rotary kiln cylinder in the length direction is a feeding end, the other end in the length direction is a discharging end, and a containing cavity is formed inside the rotary kiln cylinder; an oxygen-enriched air delivery pipe, the oxygen-enriched air delivery pipe is arranged inside the containing cavity, a gas delivery pipeline is formed inside the oxygen-enriched air delivery pipe, the gas delivery pipeline is suitable for delivering oxygen-enriched air to the containing cavity, and a plurality of first nozzles are formed on the oxygen-enriched air delivery pipe; a coal powder delivery pipe, the coal powder delivery pipe is arranged inside the containing cavity, a coal powder delivery pipeline is formed inside the coal powder delivery pipe, and a plurality of second nozzles are formed on the coal powder delivery pipe. Thus, the net calorific value of coal is increased, coal consumption is reduced, production costs are reduced, and the amount of flue gas is reduced.

[0005] The rotary kiln proposed in the utility model also has the following additional technical features:

[0006] According to some embodiments of the utility model, the oxygen-enriched air delivery pipe includes an injection area, in which a plurality of first nozzles arranged at intervals are arranged in the circumferential direction of the oxygen-enriched air delivery pipe, thereby improving the delivery efficiency of the oxygen-enriched air and the net calorific value of the coal.

[0007] According to some embodiments of the utility model, a plurality of the jetting areas are arranged at intervals on the oxygen-enriched air conveying pipe, thereby improving the conveying efficiency of the oxygen-enriched air and the net calorific value of the coal.

[0008] According to some embodiments of the utility model, at least one of the following conditions is met: in the length direction of the rotary kiln cylinder, the distance between two adjacent jet areas is 3 cm to 5 cm; in the circumferential direction of the oxygen-enriched air delivery pipe, the number of the first nozzles is 4 to 8. Thus, the oxygen-enriched air is evenly delivered to the accommodating cavity of the rotary kiln cylinder, thereby increasing the net calorific value of coal.

[0009] According to some embodiments of the utility model, the oxygen-enriched air delivery pipe includes a first pipe wall, the first pipe wall defines the gas delivery pipeline, and the first pipe wall includes: a first ramming material layer, the first ramming material layer is arranged close to the gas delivery pipeline; a second ramming material layer, the second ramming material layer is arranged on a side of the first ramming material layer away from the gas delivery pipeline, and a gap is formed between the second ramming material layer and the first ramming material layer. Thus, the heat resistance of the oxygen-enriched air delivery pipe is improved.

[0010] According to some embodiments of the utility model, the oxygen-enriched air delivery pipe is constructed as a cylindrical barrel, and the diameter of the oxygen-enriched air delivery pipe is 300mm-500mm, thereby improving the delivery efficiency of the oxygen-enriched air and the net calorific value of the coal.

[0011] According to some embodiments of the present invention, the rotary kiln further comprises: a support frame, which is arranged inside the oxygen-enriched air delivery pipeline and is suitable for supporting the oxygen-enriched air delivery pipe. Thus, the oxygen-enriched air delivery pipe is supported in the accommodating cavity of the rotary kiln cylinder to uniformly deliver oxygen-enriched air into the rotary kiln cylinder.

[0012] According to some embodiments of the present invention, a plurality of support frames are arranged at intervals in the length direction of the rotary kiln cylinder, thereby improving the stability of the oxygen-enriched air delivery pipe.

[0013] According to some embodiments of the utility model, the pulverized coal conveying pipe is arranged in contact with the oxygen-enriched air conveying pipe, thereby improving the contact efficiency between the oxygen-enriched air and the coal, causing the coal to burn quickly and increasing the reaction rate.

[0014] According to some embodiments of the utility model, the rotary kiln further comprises: a kiln tail cover, which is arranged at the feeding end; a kiln head cover, which is arranged at the discharging end; a first rotary joint is formed at one end of the oxygen-enriched air delivery pipe, which is connected to the kiln tail cover, and a second rotary joint is formed at the other end of the oxygen-enriched air delivery pipe, which is connected to the kiln head cover. Thus, when the oxygen-enriched air delivery pipe rotates together with the rotary kiln cylinder, the sealing performance of the rotary kiln is improved.

[0015] According to some embodiments of the utility model, the rotary kiln cylinder includes a second tube wall, the second tube wall defines the accommodating cavity, and the material of the second tube wall includes a rotary kiln refractory material, thereby improving the heat resistance of the rotary kiln. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 The schematic diagram of the structure of a rotary kiln according to an embodiment of the utility model is shown.

[0018] Figure 2 A cross-sectional view of an oxygen-enriched air delivery pipe according to an embodiment of the present invention is shown.

[0019] Reference numerals:

[0020] 1: rotary kiln; 11: rotary kiln cylinder; 111: accommodating chamber; 112: second tube wall; 12: oxygen-enriched air conveying pipe; 121: gas conveying pipeline; 122: first nozzle; 123: first ramming material layer; 124: second ramming material layer; 125: gap; 126: first rotary joint; 127: second rotary joint; 13: pulverized coal conveying pipe; 14: support frame; 15: kiln tail cover; 16: kiln head cover; 17: support and transmission mechanism; 18: feeding pipe; 19: smoke outlet. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0022] During the reduction of iron ore in a rotary kiln, the iron ore pellets are dried and preheated before being added to the rotary kiln. Then, pulverized coal is sprayed into the kiln through the kiln head spray gun. Due to the large amount of heat absorption during the reduction process and the need to maintain a sufficiently strong reducing atmosphere, several blowers are usually hung on the outer shell of the rotary kiln to blow air evenly in the longitudinal direction of the rotary kiln. This method has the following shortcomings: ① The oxygen content in the air is low, and the net calorific value of coal is low, resulting in high coal consumption and large flue gas volume; ② When the fan rotates with the rotary kiln, when the wind shield is located at the bottom of the rotary kiln, the blast directly enters the material layer, interrupting the reduction process and causing additional consumption of coal.

[0023] The utility model proposes a rotary kiln 1, referring to Figure 1The rotary kiln 1 comprises a rotary kiln cylinder 11, one end of the rotary kiln cylinder 11 in the length direction is a feeding end, and the other end in the length direction is a discharging end, and a accommodating cavity 111 is formed inside the rotary kiln cylinder 11; an oxygen-enriched air delivery pipe 12, the oxygen-enriched air delivery pipe 12 is arranged inside the accommodating cavity 111, and a gas delivery pipeline 121 is formed inside the oxygen-enriched air delivery pipe 12, and the gas delivery pipeline 121 is suitable for delivering oxygen-enriched air into the accommodating cavity 111, and the oxygen concentration in the oxygen-enriched air is greater than or equal to 50%, and a plurality of first nozzles 122 (reference Figure 2 ); a pulverized coal conveying pipe 13, the pulverized coal conveying pipe 13 is arranged inside the accommodating chamber 111, a pulverized coal conveying pipeline 13 is formed inside the pulverized coal conveying pipe 13, and a plurality of second nozzles (not shown in the figure) are formed on the pulverized coal conveying pipe 13. Specifically, the iron ore enters the accommodating chamber 111 through the feeding end of the rotary kiln cylinder 11, the oxygen-enriched air of the oxygen-enriched air conveying pipe 12 conveys the oxygen-enriched air to the accommodating chamber 111 through the first nozzle 122, and the coal in the pulverized coal conveying pipe 13 conveys the coal to the accommodating chamber 111 of the rotary kiln cylinder 11 through the second nozzle. After the coal is burned, heat is released to maintain the high temperature environment required for the reduction reaction. At the same time, after the coal is burned, CO is released, and CO acts as a reducing agent to reduce iron oxides into metallic iron.

[0024] The rotary kiln 1 proposed in the utility model improves the combustion efficiency of coal and the net calorific value of coal by conveying oxygen-enriched air into the rotary kiln cylinder 11, thereby reducing coal consumption, reducing smoke production, and reducing environmental pollution. At the same time, the oxygen-enriched air conveying pipe 12 is located inside the accommodating chamber 111 of the rotary kiln cylinder 11. When conveying oxygen-enriched air into the accommodating chamber 111, the impact on the material layer and the impact on the reduction reaction can be reduced, thereby reducing the production cost and improving the reaction efficiency and production efficiency.

[0025] According to some embodiments of the utility model, the oxygen concentration in the oxygen-enriched air is greater than or equal to 50%, thereby increasing the net calorific value of coal, reducing coal consumption, reducing production costs, and reducing flue gas volume.

[0026] According to some embodiments of the present invention, the temperature of the oxygen-enriched air may be 1000°C-1200°C.

[0027] According to some embodiments of the present invention, the rotary kiln 1 is tilted as a whole. Specifically, the feeding end is high and the discharging end is low, so that the material can be easily moved from the feeding end to the discharging end.

[0028] According to some embodiments of the present invention, the oxygen-enriched air delivery pipe 12 includes an injection area, in which a plurality of first nozzles 122 arranged at intervals are arranged in the circumferential direction of the oxygen-enriched air delivery pipe 12. Specifically, in the injection area, the plurality of first nozzles 122 arranged in the circumferential direction of the oxygen-enriched air delivery pipe 12 may be arranged at equal intervals (refer to Figure 2 ) to improve the uniformity of oxygen-enriched air in the accommodating chamber 111 of the rotary kiln 1; or the plurality of first nozzles 122 on the circumferential direction of the oxygen-enriched air delivery pipe 12 can be arranged according to the distribution of coal in the accommodating chamber 111. More first nozzles 122 can be arranged at locations where more coal is distributed, and the number of first nozzles 122 can be reduced accordingly at locations where less coal is distributed. Thus, the contact efficiency between oxygen-enriched air and coal is improved, and the utilization rate of oxygen-enriched air is improved.

[0029] According to some embodiments of the present invention, a plurality of the injection areas are arranged at intervals on the oxygen-enriched air delivery pipe 12. Figure 1 In the longitudinal direction of the rotary kiln shell 11, a plurality of the first nozzles 122 are arranged at intervals. Thus, the uniformity of the distribution of the oxygen-enriched air in the accommodating chamber 111 of the rotary kiln shell 11 is improved, the combustion efficiency of the coal is improved, and the net calorific value of the coal is increased.

[0030] According to some embodiments of the present invention, in the length direction of the rotary kiln cylinder 11, the distances between two adjacent air injection areas are equal, thereby improving the uniformity of the distribution of oxygen-enriched air in the accommodating cavity 111 of the rotary kiln cylinder 11.

[0031] According to some embodiments of the utility model, in the length direction of the rotary kiln cylinder 11, the distance between two adjacent jet areas can be 3 cm-5 cm, for example, 3 cm, 3.5 cm, 4 cm, 4.5 cm or 5 cm, or can be a range of any of the above values. Thus, the volume of oxygen-enriched air delivered by the oxygen-enriched air delivery pipe 12 to the accommodating chamber 111 of the rotary kiln cylinder 11 per unit time is increased, the oxygen content in the accommodating chamber 111 is increased, the uniformity of oxygen distribution in the accommodating chamber 111 is increased, the combustion efficiency of coal is improved, and the net calorific value of coal is increased.

[0032] According to some embodiments of the present invention, reference Figure 2, the number of the first nozzles 122 is 4-8 in the circumferential direction of the oxygen-enriched air delivery pipe 12. For example, the number may be 4, 5, 6, 7 or 8, or may be a range of any of the above values. Thus, the volume of oxygen-enriched air delivered by the oxygen-enriched air delivery pipe 12 to the accommodating chamber 111 of the rotary kiln cylinder 11 per unit time is increased, the oxygen content in the accommodating chamber 111 is increased, the uniformity of oxygen distribution in the accommodating chamber 111 is increased, the combustion efficiency of coal is improved, and the net calorific value of coal is increased.

[0033] According to some embodiments of the present invention, the oxygen-enriched air delivery pipe 12 includes a first pipe wall, and the first pipe wall defines the gas delivery pipeline 121. Figure 2 The first tube wall includes: a first ramming material layer 123, the first ramming material layer 123 is arranged close to the gas delivery pipeline 121; a second ramming material layer 124, the second ramming material layer 124 is arranged on a side of the first ramming material layer 123 away from the gas delivery pipeline 121, and a gap 125 is formed between the second ramming material layer 124 and the first ramming material layer 123. Specifically, a plurality of first nozzles 122 penetrate the first tube wall, and the oxygen-enriched air in the oxygen-enriched air delivery pipe 12 is delivered to the accommodating chamber 111 of the rotary kiln cylinder 11 through the first nozzles 122. The gap 125 between the first ramming material layer 123 and the second ramming material layer 124 can be used as a water cooling channel to cool the oxygen-enriched air delivery pipe 12 and reduce the temperature of the oxygen-enriched air delivery pipe 12. At the same time, the first ramming material layer 123 and the second ramming material layer 124 can reduce the heat transfer of high-temperature flue gas and high-temperature oxygen-enriched air to the oxygen-enriched air conveying pipe 12 , reduce the temperature of the oxygen-enriched air pipe, and improve the strength of the oxygen-enriched air conveying pipe 12 .

[0034] According to some embodiments of the utility model, the oxygen-enriched air delivery pipe 12 is configured as a cylindrical barrel, and the diameter of the oxygen-enriched air delivery pipe 12 is 300 mm-500 mm. For example, it can be 300 mm, 350 mm, 400 mm, 450 mm or 500 mm, or can be a range of any of the above values. Thus, the rate of delivering oxygen-enriched air into the accommodating chamber 111 of the rotary kiln barrel 11 is provided.

[0035] It should be noted that the diameter of the oxygen-enriched air delivery pipe referred to here refers to the diameter of the circular cross-section.

[0036] According to some embodiments of the present invention, reference Figure 1The rotary kiln 1 may further include: a support frame 14, which is arranged outside the oxygen-enriched air delivery pipe 12 and is suitable for supporting the oxygen-enriched air delivery pipe 12. Specifically, the rotary kiln cylinder 11 includes a second tube wall 112, and the second tube wall 112 defines the accommodating chamber 111. One end of the support frame 14 is connected to the first tube wall of the oxygen-enriched air delivery pipe 12, and the other end of the support frame 14 is connected to the second tube wall 112 of the rotary kiln cylinder 11. The support frame 14 supports the oxygen-enriched air delivery pipe 12 in the accommodating chamber 111, and the first tube wall and the second tube wall 112 are not in contact. The oxygen-enriched air delivery pipe 12 is circumferentially arranged with a plurality of first nozzles 122, and the first nozzles 122 can spray oxygen-enriched air into the entire accommodating chamber 111, thereby improving the uniformity of oxygen distribution in the accommodating chamber 111, thereby improving the combustion rate of coal, increasing the net calorific value of coal, reducing coal consumption, and reducing flue gas production.

[0037] According to some embodiments of the present invention, reference Figure 1 , in the length direction of the rotary kiln cylinder 11, a plurality of the support frames 14 are arranged at intervals. Specifically, in the length direction of the rotary kiln cylinder 11, the distances between the plurality of the support frames 14 are the same. According to some specific embodiments of the utility model, the distance between two adjacent support frames 14 can be 5cm-8cm, for example, 5cm, 6cm, 7cm or 8cm, etc., or can be a range composed of any of the above values. Thereby, the stability of the oxygen-enriched air delivery pipe 12 in the accommodating chamber 111 is improved.

[0038] According to some embodiments of the present invention, a water cooling channel is further provided on the support frame 14 , and the water cooling channel is communicated with the gap 125 in the oxygen-enriched air delivery pipe 12 .

[0039] According to some embodiments of the present invention, reference Figure 2 The pulverized coal delivery pipe 13 is arranged in contact with the oxygen-enriched air delivery pipe 12. Specifically, the pulverized coal delivery pipe 13 is hung on the outside of the oxygen-enriched air delivery pipe 12, and the coal sprayed from the second nozzle can quickly contact with the oxygen-enriched air sprayed from the first nozzle 122, thereby increasing the combustion rate of the coal.

[0040] According to some embodiments of the present invention, reference Figure 1The rotary kiln 1 may further include: a kiln tail hood 15, which is arranged at the feeding end; a kiln head hood 16, which is arranged at the discharging end; a first rotary joint 126 is formed at one end of the oxygen-enriched air conveying pipe 12, and the first rotary joint 126 is connected to the kiln tail hood 15, and a second rotary joint 127 is formed at the other end of the oxygen-enriched air conveying pipe 12, and the second rotary joint 127 is connected to the kiln head hood 16. Specifically, the kiln tail cover 15 is arranged at the feeding end, and the feeding end is also provided with a feeding pipe 18 and a flue gas outlet 19. The iron ore enters the accommodating chamber 111 of the rotary kiln cylinder 11 through the feeding pipe 18. The rotary kiln 1 also includes a support and transmission mechanism 17. The oxygen-enriched air delivery pipe 12 rotates synchronously with the rotary kiln cylinder 11. The oxygen-enriched air of the oxygen-enriched air delivery pipe 12 is delivered to the accommodating chamber 111 through the first nozzle 122. The coal in the coal powder delivery pipe 13 is delivered to the accommodating chamber 111 of the rotary kiln cylinder 11 through the second nozzle. After the coal is burned, heat is released to maintain the high temperature environment required for the reduction reaction. At the same time, after the coal is burned, CO is released. CO acts as a reducing agent to reduce iron oxides into metallic iron. The coal gas generated by the coal combustion is discharged through the coal gas outlet 19. Therefore, the kiln head cover 16 and the kiln tail cover 15 can improve the sealing of the rotary kiln 1, reduce heat loss, and improve the efficiency of the reduction reaction in the rotary kiln 1.

[0041] According to some embodiments of the present invention, reference Figure 1 The rotary kiln cylinder 11 includes a second tube wall 112, the second tube wall 112 defines the accommodating cavity 111, and the material of the second tube wall 112 includes a rotary kiln refractory material, thereby improving the high temperature resistance of the second tube wall 112.

[0042] In the present invention, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A rotary kiln, characterized in that: include: A rotary kiln cylinder, wherein one end of the rotary kiln cylinder in the length direction is a feeding end, the other end in the length direction is a discharging end, and a containing cavity is formed inside the rotary kiln cylinder; an oxygen-enriched air delivery pipe, the oxygen-enriched air delivery pipe being arranged inside the accommodating chamber, a gas delivery pipeline being formed inside the oxygen-enriched air delivery pipe, the gas delivery pipeline being suitable for delivering oxygen-enriched air into the accommodating chamber, and a plurality of first nozzles being formed on the oxygen-enriched air delivery pipe; A pulverized coal delivery pipe is provided inside the accommodating cavity, a pulverized coal delivery pipeline is formed inside the pulverized coal delivery pipe, and a plurality of second nozzles are formed on the pulverized coal delivery pipe.

2. The rotary kiln according to claim 1, characterized in that: The oxygen-enriched air delivery pipe comprises an injection area, in which a plurality of first nozzles arranged at intervals are arranged in the circumferential direction of the oxygen-enriched air delivery pipe.

3. The rotary kiln according to claim 2, characterized in that: A plurality of the jetting areas are arranged at intervals on the oxygen-enriched air conveying pipe.

4. The rotary kiln according to claim 3, characterized in that: Satisfy at least one of the following conditions: In the length direction of the rotary kiln shell, the distance between two adjacent air-jet areas is 3 cm to 5 cm; In the circumferential direction of the oxygen-enriched air delivery pipe, the number of the first nozzles is 4-8.

5. The rotary kiln according to any one of claims 1 to 4, characterized in that: The oxygen-enriched air delivery pipe comprises a first pipe wall, the first pipe wall defines the gas delivery pipeline, and the first pipe wall comprises: a first ramming material layer, wherein the first ramming material layer is disposed close to the gas delivery pipeline; A second ramming material layer is provided on a side of the first ramming material layer away from the gas conveying pipeline, and a gap is formed between the second ramming material layer and the first ramming material layer.

6. The rotary kiln according to claim 5, characterized in that: The oxygen-enriched air delivery pipe is constructed as a cylindrical barrel, and the diameter of the oxygen-enriched air delivery pipe is 300mm-500mm.

7. The rotary kiln according to claim 5, characterized in that: Also includes: A support frame is arranged inside the oxygen-enriched air delivery pipeline and is suitable for supporting the oxygen-enriched air delivery pipe.

8. The rotary kiln according to claim 7, characterized in that: In the length direction of the rotary kiln shell, a plurality of support frames are arranged at intervals.

9. The rotary kiln according to claim 5, characterized in that: The pulverized coal conveying pipe is arranged in contact with the oxygen-enriched air conveying pipe.

10. The rotary kiln according to claim 5, characterized in that: The rotary kiln also includes: A kiln tail hood, the kiln tail hood being arranged at the feeding end; A kiln head cover, the kiln head cover is arranged at the discharge end; A first rotary joint is formed at one end of the oxygen-enriched air delivery pipe, and the first rotary joint is connected to the kiln tail cover. A second rotary joint is formed at the other end of the oxygen-enriched air delivery pipe, and the second rotary joint is connected to the kiln head cover.

11. The rotary kiln according to claim 5, characterized in that: The rotary kiln cylinder includes a second tube wall, the second tube wall defines the accommodating cavity, and the material of the second tube wall includes rotary kiln refractory material.

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