Limestone calcining device

Abstract

The utility model relates to the technical field of limestone calcination, in particular to a limestone calcination device which comprises a rotary kiln and a preheater, a coarse material bin, a first preheating area, a second preheating area and a discharging chute are distributed in the preheater from top to bottom, and a coarse material inlet is formed in the top of the coarse material bin. The coarse material bin is communicated with the first preheating area through a plurality of blanking pipes, a preheating table used for receiving blanking materials is arranged in the second preheating area, the preheater is provided with a material pushing mechanism used for pushing the materials on the preheating table into the discharging chute, and a fine material inlet is formed in the side wall of the preheater in the second preheating area. And the fine material inlet is externally connected with a fine material feeding mechanism. By using the device, the preheating effect of coarse material particles and fine material particles is improved, the coarse material particles and the fine material particles can be decomposed more completely after entering the rotary kiln, the quality of calcium oxide is improved, in the whole production process, the energy loss is reduced, the utilization rate of raw materials and resources and the overall production efficiency are improved, and the production cost is greatly saved.

Description

Technical Field

[0001] The utility model belongs to the technical field of limestone calcination, and particularly relates to a limestone calcination device. Background Art

[0002] When limestone is calcined, it is usually fed uniformly from the top of the preheater. The conveyed limestone raw materials are transported to the preheating platform in the preheating chamber through the blanking pipe, and then the preheated raw materials are pushed out by cooperating with the pushing mechanism, so that the raw materials enter the rotary kiln for calcination. However, during the preheating process, the limestone raw materials will accumulate on the preheating platform, and the gaps formed by the coarse material particles will be blocked by the fine material particles, resulting in the hot air being unable to penetrate the material layer, leading to poor ventilation. This will not only cause incomplete combustion of pulverized coal, but also the raw materials cannot be preheated evenly and sufficiently, and the raw materials entering the rotary kiln cannot be decomposed evenly and sufficiently, resulting in phenomena such as underburning and overburning, seriously affecting the quality of calcium oxide. Content of the Utility Model

[0003] In order to overcome the deficiencies of the prior art and solve the problems existing in the prior art, the utility model provides a limestone calcination device.

[0004] The utility model is realized through the following technical solutions.

[0005] A limestone calcination device provided by the utility model includes a rotary kiln and a preheater. In the preheater, a coarse material bin, a first preheating area, a second preheating area, and a discharge chute with the bottom connected to the feed inlet of the rotary kiln are distributed from top to bottom. A coarse material inlet is arranged at the top of the coarse material bin. The coarse material bin is communicated with the first preheating area through a plurality of blanking pipes. A preheating platform for receiving the falling materials is arranged in the second preheating area. A pushing mechanism for pushing the materials on the preheating platform into the discharge chute is arranged on the preheater. A fine material inlet is constructed on the side wall of the preheater in the second preheating area, and a fine material feeding mechanism is externally connected to the fine material inlet.

[0006] As a further improvement of the above solution, 12 - 14 blanking pipes are arranged, and the blanking pipes are distributed in a ring shape. A pushing mechanism is arranged corresponding to each blanking pipe; the preheating platform is constructed in a ring shape, and a circular blanking port is constructed in the middle of the preheating platform.

[0007] As a further improvement of the above solution, the ring width of the preheating platform is not less than 1.5 m. A slope is constructed on one side of the preheating platform close to the circular blanking port, and the included angle between the slope and the horizontal plane is 20°.

[0008] As a further improvement of the above solution, the lower port of the blanking pipe extends into the first preheating area, and the distance between the lower port of the blanking pipe and the upper surface of the preheating platform is 1 m - 2.8 m.

[0009] As a further improvement of the above solution, the fine material feeding mechanism includes a first screw conveyor and a second screw conveyor. The discharge port of the first screw conveyor is connected to the feed port of the second screw conveyor. The discharge port of the second screw conveyor is connected to the fine material inlet. The feed port of the first screw conveyor is externally connected to a material conveying mechanism.

[0010] As a further improvement of the above solution, a high-temperature resistant layer is provided on the inner wall of the fine material inlet. The discharge port of the second screw conveyor is connected to the fine material inlet through an extension port, and the extension port is made of heat-resistant steel.

[0011] As a further improvement of the above solution, the length of the extension port is 30 - 50 cm; the blade thickness of the first screw conveyor is not less than 10 mm; the second screw conveyor is a shaftless screw conveyor, and the blade thickness of the second screw conveyor is not less than 15 mm.

[0012] As a further improvement of the above solution, the material conveying mechanism includes a fine material feeding hopper. A weighing and transporting belt is provided below the fine material feeding hopper. A hoist is provided at the tail end of the weighing and transporting belt. The discharge port of the hoist is connected to the feed port of the first screw conveyor from top to bottom.

[0013] As a further improvement of the above solution, a sandwich layer is provided between the coarse material bin and the first preheating zone. The blanking pipe is a telescopic pipe. The blanking pipe includes an outer upper pipe. The outer upper pipe is located in the sandwich layer, fixed to the bottom of the coarse material bin, and communicated with the blanking port at the bottom of the coarse material bin. The outer upper pipe is slidably connected with an inner lower pipe. The lower port of the inner lower pipe extends into the first preheating zone. An adjusting mechanism for adjusting the distance between the lower port of the inner lower pipe and the upper surface of the preheating table is provided in the sandwich layer, and the adjusting range of the distance is 1 m - 2.8 m.

[0014] As a further improvement of the above solution, the adjusting mechanism is an electric hoist installed at the bottom of the coarse material bin. The electric hoist has a hook. A hanging ring is provided on the outer wall of the inner lower pipe corresponding to the hook, and the hanging ring is located in the sandwich layer.

[0015] The beneficial effects achieved by the present utility model are:

[0016] Compared with the prior art, a limestone calcination device provided by the present utility model modifies the feeding method into a top coarse material feeding and a side fine material feeding method according to the different particle sizes of limestone, separates the coarse material particles from the fine material particles, preheats them separately, so that the gaps between the coarse material particles will not be blocked by the fine material particles, enabling the hot air to completely penetrate the coarse material layer, having a larger preheating area that can directly contact with the hot air, improving the preheating effect on the coarse material particles, enabling them to decompose more completely after entering the rotary kiln, and improving the quality of calcium oxide; at the same time, compared with the prior art, since the technical problems proposed by the present utility model cannot be solved, most manufacturers choose to directly remove the fine material particles, increase the preheating temperature or directly select the coarse material particles as raw materials. In the present utility model, the fine material particles are fully and completely utilized. Due to their small particle size and increased self-preheating area, a better preheating effect can be achieved during the process of sliding to the rotary kiln in the second preheating zone, enabling them to decompose more completely after entering the rotary kiln and improving the quality of calcium oxide. In summary, the limestone calcination device provided by the present utility model reduces energy consumption, improves the utilization rate of raw materials, resources and the overall production efficiency, and greatly saves production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the preheater in the present utility model;

[0018] Figure 2 is a schematic structural diagram of the preheater and the rotary kiln in the present utility model;

[0019] Figure 3 is a schematic structural diagram of the preheating table in the present utility model;

[0020] Figure 4 is a schematic structural diagram of the adjusting mechanism in the present utility model;

[0021] Figure 5 is the present utility model Figure 1 an enlarged view of A therein;

[0022] Figure 6 is the present utility model Figure 4 an enlarged view of B therein.

[0023] In the figure: coarse material bin 1, coarse material inlet 101, first preheating zone 2, second preheating zone 3, rotary kiln 4, discharge chute 5, blanking pipe 6, outer upper pipe 601, inner lower pipe 602, lifting ring 603, preheating table 7, circular blanking opening 701, slope 702, pushing mechanism 8, fine material inlet 9, high-temperature resistant layer 901, first screw conveyor 10, second screw conveyor 11, extension opening 1101, fine material feeding hopper 12, weighing and transporting belt 13, elevator 14, interlayer 15, adjusting mechanism 16, electric hoist 1601, hook 1602. Detailed implementation mode

[0024] The present utility model will be further described in detail below in conjunction with the drawings and embodiments.

[0025] As Figures 1 to 6 shown, a limestone calcination device provided by the present utility model includes a rotary kiln 4 and a preheater. In the preheater, a coarse material bin 1, a first preheating zone 2, a second preheating zone 3, and a discharge chute 5 with its bottom connected to the feed inlet of the rotary kiln 4 are distributed from top to bottom. The side wall of the second preheating zone 3 has a certain slope and is smoothly transitioned with the discharge chute 5 to facilitate the entry of fine materials into the rotary kiln. A coarse material inlet 101 is provided at the top of the coarse material bin 1. The coarse material bin 1 is communicated with the first preheating zone 2 through a plurality of blanking pipes 6. A preheating table 7 for receiving the falling materials is arranged in the second preheating zone 3. A pushing mechanism 8 for pushing the materials on the preheating table 7 into the discharge chute 5 is arranged on the preheater. The pushing mechanism is a prior art and will not be elaborated here. A fine material inlet 9 is constructed on the side wall of the preheater of the second preheating zone 3, and the fine material inlet 9 is externally connected with a fine material feeding mechanism.

[0026] Specifically, coarse materials are input from the top of the preheater, and after being preheated successively in the first preheating zone 2 and the second preheating zone 3, they enter the calcination process for calcination. Fine materials are input from the side of the preheater, and after being preheated in the second preheating zone 3, they enter the calcination process for calcination. In addition, the side wall of the second preheating zone 3 of the preheater is a chute structure with a certain slope, which facilitates the sliding of materials into the rotary kiln 4.

[0027] Specifically, there are also crushing and screening processes before the preheating process and the calcination process. In this embodiment, the coarse materials are limestone raw materials with a minimum particle size of not less than 1 cm, and the fine materials are limestone raw materials with a maximum particle size of not more than 1 cm. Specifically, in this implementation, the coarse materials are limestone raw materials with a particle size of 1 - 4 cm.

[0028] Furthermore, in the preheater, high-temperature gas generated in the calcination process is introduced into the second preheating zone 3 and the first preheating zone 2 from the rotary kiln through a high-temperature induced draft fan to preheat the raw materials. The preheating temperature of the second preheating zone 3 is 950 - 1100 °C, and the preheating pressure is -80 - -200 Pa. The preheating temperature of the first preheating zone 2 is 850 °C - 1050 °C, and the preheating pressure is -1500 Pa - -2500 Pa. The preheating effect of the coarse-grained materials preheated in the first preheating zone 2 can reach 30%, that is, 30% of the coarse grains are decomposed into calcium oxide from the outside to the inside. The preheating effect of the fine-grained materials preheated in the second preheating zone 3 can reach 50%, that is, 50% of the fine-grained materials are decomposed into calcium oxide from the outside to the inside, and then enter the rotary kiln 4.

[0029] Furthermore, in this embodiment, 12 - 14 blanking pipes 6 are provided, and the blanking pipes 6 are annularly distributed. A pushing mechanism 8 is provided corresponding to each blanking pipe 6.

[0030] Further, the preheating table 7 is configured as a ring shape, and a circular blanking port 701 is formed in the middle of the preheating table 7. The pushing mechanism 8 pushes the blanking into the circular blanking port 701, and it falls to the discharge chute 5.

[0031] Further, the ring width of the preheating table 7 is not less than 1.5 m.

[0032] Further, a slope 702 is formed on one side of the preheating table 7 close to the circular blanking port 701. The included angle between the slope 702 and the horizontal plane is 20°, which is convenient for the coarse material to slide into the rotary kiln and avoids the excessive inward extension of the pushing head of the pushing mechanism 8.

[0033] Further, the lower port of the blanking pipe 6 extends into the first preheating zone 2, and the distance between the lower port of the blanking pipe 6 and the upper surface of the preheating table 7 is 1 m to 2.8 m.

[0034] Specifically, the fine material feeding mechanism includes a first screw conveyor 10 and a second screw conveyor 11. The discharge port of the first screw conveyor 10 is connected to the feed port of the second screw conveyor 11, the discharge port of the second screw conveyor 11 is connected to the fine material inlet 9, and the feed port of the first screw conveyor 10 is externally connected with a feeding mechanism.

[0035] Specifically, the first screw conveyor 10 is located above the second screw conveyor 11. The discharge port of the first screw conveyor 10 is connected downward to the feed port of the second screw conveyor 11, and the discharge port of the second screw conveyor 11 is connected to the fine material inlet 9.

[0036] Further, a high-temperature resistant layer 901 is provided on the inner wall of the fine material inlet 9. The high-temperature resistant layer 901 is composed of refractory bricks, which can avoid the high-temperature deformation of the discharge port of the second screw conveyor 11.

[0037] Further, the discharge port of the second screw conveyor 11 is connected to the fine material inlet 9 through an extension port 1101. The extension port 1101 is made of heat-resistant steel to avoid the deformation of the extension port 1101.

[0038] Further, the length of the extension port 1101 is 30 - 50 cm, and the extension port 1101 can be integrally provided with the discharge port of the second screw conveyor 11. While avoiding the damage of the second screw conveyor 11 caused by high temperature, the material is extruded forward and will accumulate in the extension port 1101 to form a seal, playing a good role in locking air and avoiding the leakage of hot air, which may cause problems in the production system.

[0039] Further, the blade thickness of the first screw conveyor 10 is not less than 10 mm. The limestone raw material particles are relatively hard, which can avoid the deformation or jamming of the blades.

[0040] Furthermore, to prevent the shaft end of the second screw conveyor 11 from deforming due to high temperature, the second screw conveyor 11 is a shaftless screw conveyor, and the blade thickness of the second screw conveyor 11 is not less than 15 mm. The limestone raw material particles are relatively hard, preventing the blades from deforming or jamming.

[0041] Specifically, the feeding mechanism includes a fine material feeding hopper 12. A weighing and transporting belt 13 is arranged below the fine material feeding hopper 12. A hoist 14 is arranged at the tail end of the weighing and transporting belt 13. The discharge port of the hoist 14 is connected to the feeding port of the first screw conveyor 10 from top to bottom.

[0042] Furthermore, to ensure production efficiency and production benefits, in the prior art, the rotary kiln has relatively strict requirements for the particle size of raw material particles. Usually, limestone raw material particles with a particle size of 2 cm - 4 cm are directly calcined. However, during the crushing process of raw material particles with a particle size of 2 cm - 4 cm, the highest recovery rate does not exceed 60%, which is a great waste for the rotary kiln to calcine the mine. The remaining materials with a particle size of less than 2 cm cannot be reasonably utilized. Therefore, the price of limestone raw materials with a particle size of 2 cm - 4 cm is much higher than that of 1 cm - 2 cm, increasing the production cost. The utility model solves the problem of calcining particles less than 1 cm through the side fine material feeding method and further improves the limestone raw material particles with a particle size of 2 - 4 cm.

[0043] Further improvement: In the prior art, the length of the blanking pipe 6 is selected according to actual production requirements and is fixed. The utility model has conducted a more in-depth study on the above problems and changed the blanking pipe 6 to a telescopic pipe structure. The principle is that the material has a layer thickness on the preheating table, and the layer thickness depends on the distance between the lower port of the blanking pipe 6 and the upper surface of the preheating table 7. In this embodiment, for raw material particles with a particle size of 2 cm - 4 cm, a pipe-to-table distance of 2.8 m is adopted. At this distance, the raw material particles with a particle size of 2 cm - 4 cm can maintain sufficient gaps between each other, enabling the hot air to penetrate smoothly and achieving the expected preheating effect. However, the 2.8 m pipe-to-table distance is not applicable to 1 cm - 2 cm. Since the raw material particles with a particle size of 1 cm - 2 cm are smaller, their layer height is too high, which will cause the hot air to be unable to penetrate the material layer, resulting in poor ventilation, and further causing incomplete combustion of pulverized coal and insufficient preheating of the raw materials. The inadequately preheated raw materials cannot be evenly and fully decomposed after entering the rotary kiln 4, resulting in underburning and overburning phenomena and affecting the quality of calcium oxide. Therefore, by changing the blanking pipe 6 to a telescopic pipe structure, the lower port of the blanking pipe 6 can be lowered, and then after adjusting the material layer, in this embodiment, for the calcination of raw material particles with a particle size of 1 cm - 2 cm, the lower port of the blanking pipe is lowered to 1 m above the upper surface of the preheating table 6.

[0044] Specifically, the blanking pipe 6 is a telescopic pipe. By adjusting the distance between the lower port of the blanking pipe 6 and the preheating table 7, the thickness of the material layer on the preheating table 7 is adjusted.

[0045] Specifically, a sandwich layer 15 is provided between the coarse material bin 1 and the first preheating zone 2. The blanking pipe 6 includes an outer upper pipe 601 which is located in the sandwich layer 15, fixed to the bottom of the coarse material bin 1, and communicated with the blanking port at the bottom of the coarse material bin 1. The outer upper pipe 601 is slidably connected with an inner lower pipe 602, and the lower port of the inner lower pipe 602 extends into the first preheating zone 2. An adjusting mechanism 16 for adjusting the distance between the lower port of the inner lower pipe 602 and the upper surface of the preheating table 7 is arranged in the sandwich layer 15, and the adjusting range of the distance is 1 m to 2.8 m.

[0046] Specifically, compared with the telescopic pipe structure with the inner pipe on the upper side and the outer pipe on the lower side, in this embodiment, the outer upper pipe 601 and the inner lower pipe 602 can also play a good sealing role to avoid the leakage of hot air.

[0047] Specifically, the adjusting mechanism 16 is an electric hoist 1601 installed at the bottom of the coarse material bin 1. The electric hoist 1601 has a hook 1602. A lifting ring 603 is arranged on the outer wall of the inner lower pipe 602 corresponding to the hook 1602. The hanging ring is located in the sandwich layer 15. The electric hoist 1601 is a chain electric hoist or a wire rope electric hoist.

[0048] Specifically, the use of the electric hoist 1601 is a preferred solution, which is more convenient, faster, and labor-saving. According to the actual production scale, there can be other implementation solutions. For example, a cross beam or a pulley is arranged at the bottom of the coarse material bin 1, and the lifting ring 603 is directly pulled by a pull rope manually, and then the pulling end of the pull rope is fixed to achieve the effect of adjusting the height of the lower port of the inner lower pipe 602.

Claims

1. A limestone calcining device, comprising a rotary kiln (4) and a preheater, characterized in that: The preheater is provided with a coarse material bin (1), a first preheating zone (2), a second preheating zone (3) and a discharge chute (5) connected to the feed port of a rotary kiln (4) from top to bottom. The top of the coarse material bin (1) is provided with a coarse material inlet (101). The coarse material bin (1) is connected to the first preheating zone (2) via a plurality of drop pipes (6). The second preheating zone (3) is provided with a preheating table (7) for receiving dropped materials. The preheater is provided with a pushing mechanism (8) for pushing the materials on the preheating table (7) into the discharge chute (5). The side wall of the preheater in the second preheating zone (3) is provided with a fine material inlet (9), and the fine material inlet (9) is externally connected to a fine material feeding mechanism.

2. A limestone calcining device according to claim 1, characterized in that: The number of the drop tubes (6) is 12 to 14, the drop tubes (6) are distributed in a ring shape, and a push mechanism (8) is provided corresponding to each drop tube (6); The preheating table (7) is constructed in a ring shape, and a circular discharge opening (701) is constructed in the middle of the preheating table (7).

3. A limestone calcining device according to claim 2, characterized in that: The ring width of the preheating table (7) is not less than 1.5 m, and a slope (702) is constructed on one side of the preheating table (7) close to the circular discharge port (701), and the angle between the slope (702) and the horizontal plane is 20°.

4. A limestone calcining device according to claim 2, characterized in that: The lower end of the blanking pipe (6) extends into the first preheating zone (2), and the distance between the lower end of the blanking pipe (6) and the upper surface of the preheating table (7) is 1m to 2.8m.

5. A limestone calcining device according to claim 1, characterized in that: The fine material feeding mechanism comprises a first screw conveyor (10) and a second screw conveyor (11); the discharge port of the first screw conveyor (10) is connected to the feed port of the second screw conveyor (11); the discharge port of the second screw conveyor (11) is connected to the fine material inlet (9); and the feed port of the first screw conveyor (10) is externally connected to a feeding mechanism.

6. A limestone calcining device according to claim 5, characterized in that: A high temperature resistant layer (901) is provided on the inner wall of the fine material inlet (9), and the discharge port of the second screw conveyor (11) is connected to the fine material inlet (9) via an extension port (1101), and the extension port (1101) is made of heat resistant steel.

7. A limestone calcining device according to claim 6, characterized in that: The length of the extension opening (1101) is 30 to 50 cm; The blade thickness of the first screw conveyor (10) is not less than 10 mm; The second screw conveyor (11) is a shaftless screw conveyor, and the blade thickness of the second screw conveyor (11) is not less than 15 mm.

8. A limestone calcining device according to claim 5, characterized in that: The feeding mechanism comprises a fine material feeding hopper (12), a weighing and conveying belt (13) is arranged below the fine material feeding hopper (12), a hoist (14) is arranged at the tail end of the weighing and conveying belt (13), and the discharge port of the hoist (14) is connected from top to bottom to the feed port of the first screw conveyor (10).

9. A limestone calcining device according to claim 8, characterized in that: An interlayer (15) is provided between the coarse material bin (1) and the first preheating zone (2); the drop tube (6) is a telescopic tube; the drop tube (6) comprises an outer upper tube (601); the outer upper tube (601) is located in the interlayer (15) and is fixed to the bottom of the coarse material bin (1) and is communicated with a drop opening at the bottom of the coarse material bin (1); the outer upper tube (601) is slidably connected to an inner lower tube (602); the lower end of the inner lower tube (602) extends into the first preheating zone (2); an adjusting mechanism (16) is provided in the interlayer (15) for adjusting the distance between the lower end of the inner lower tube (602) and the upper surface of the preheating table (7); the adjustment range of the distance is 1 m to 2.8 m.

10. A limestone calcining device according to claim 9, characterized in that: The adjustment mechanism (16) is an electric hoist (1601) installed at the bottom of the coarse material bin (1), and the electric hoist (1601) has a hook (1602). A hanging ring (603) is provided on the outer wall of the inner lower tube (602) corresponding to the hook (1602), and the hanging ring is located in the interlayer (15).

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