Coal mill

Abstract

The utility model discloses a coal mill. The coal mill comprises a coal mill cylinder, a separator inner cone and a plurality of grinding rollers, wherein the separator inner cone and the grinding rollers are arranged in the coal mill cylinder. The coal mill cylinder is provided with an input end and an output end. The input end of the coal mill barrel is provided with a primary air inlet and a primary air chamber communicated with the primary air inlet, and the grinding roller is located on the side, close to the primary air chamber, of the coal mill barrel. The coal mill disclosed by the utility model has the beneficial effects that at the input end of the coal mill, primary air flowing in from the primary air inlet passes through the primary air chamber, upwards moves to pass through the grinding roller area and reaches the position near the output end of the coal mill, the primary air is redistributed, and uniform pulverized coal airflow enters the open end of the inner cone of the separator to flow; and the powder flows out of the coal mill through the powder conveying pipe until the cone end of the separator inner cone.

Description

Technical Field

[0001] The utility model belongs to the field of coal mills, and specifically relates to coal mills. Background Art

[0002] Medium-speed coal mills are important coal pulverizing equipment for large-scale thermal power units in China. After long-term use, local component wear and uneven distribution of air and pulverized coal in the outlet pipeline often occur, resulting in problems such as uneven combustion of each burner in the furnace and reduced combustion efficiency, seriously affecting the safety and economy of the operation of coal-fired boilers. The primary air passes through the wind ring from the primary air chamber and carries the ground fine coal powder particles upward. Due to the influence of the asymmetry between the primary air inlet of the coal mill and the grinding rollers, local air velocity is relatively large and the wind direction deflects in the first separation zone (the area between the inner cone and the barrel wall of the coal mill), which not only causes wear problems but also has an adverse impact on the transportation and separation of air and pulverized coal, resulting in differences in air flow velocity and pulverized coal carrying capacity between different powder conveying pipes, thus affecting the combustion efficiency of the furnace.

[0003] The utility model patent with the publication number CN214514980U and the theme name of the diversion structure applied to coal mills has an IPC classification number of B02C15 / 00 and B02C23 / 00. Its technical solution discloses that "the diversion strip 5 welded and fixed on the deflector baffle 2 is arranged obliquely downward from one side close to the side wall of the coal mill barrel 3 to the other side, and the inclination angle of the diversion strip 5 is preferably 13° - 18°; the beneficial effect of this angle design: effectively changes the flow direction of the primary pulverized air, avoids the primary pulverized air directly hitting the coal mill barrel, prevents the angle from being too large, and increases the resistance of the primary pulverized air; the design of this structure and inclination angle can better give the powder-air mixed gas a downward force to divert the powder-air mixed gas and avoid the powder-air mixed gas directly hitting the inner barrel of the coal mill."

[0004] It can be seen that the above utility model patent discloses a diversion structure applicable to a coal mill (ZGM113 medium-speed roller coal mill), and the specific implementation is a diversion strip 5 welded and fixed on the deflector baffle 2, and the diversion strip 5 is arranged obliquely downward from one side close to the side wall of the coal mill barrel 3 to the other side.

[0005] The applicant believes that the technical solution disclosed in the above utility model patent does not further completely solve problems such as "being unable to adjust the flow direction of the primary air, uneven coal powder air flow entering the separator, and uneven distribution of air and pulverized coal in the powder conveying pipe at the outlet of the coal mill", and further improvement is needed. Summary of the Utility Model

[0006] The utility model aims at the current situation of the prior art, overcomes the above defects, and provides a coal mill.

[0007] The coal mill disclosed by the present utility model mainly aims to install an arched flow guiding device on the inner wall of the coal mill cylinder body, and the installation height of the arched flow guiding device is the same as the height of the separator inlet. Under the guiding action of the arched flow guiding device, the pulverized coal air flow entering the separator is more uniform, solving the problems of uneven air powder distribution between the powder conveying pipes of the coal mill and wear on the top of the inner cavity of the coal mill cylinder body.

[0008] Another aim of the coal mill disclosed by the present utility model is to improve the uniformity of pulverized coal distribution in the powder conveying pipes of the coal mill by installing an arched flow guiding device on the cylinder wall, and design arched flow guiding devices with different installation positions and sizes according to the structure and size of the coal mill. The optimal design of the arched flow guiding device, including the installation height, position and specifications of the flow guiding device, can also be determined by means of numerical simulation calculation, so that the uniformity of pulverized coal distribution in the powder conveying pipes of the coal mill reaches the optimal.

[0009] The present utility model discloses a coal mill, which includes a coal mill cylinder body, a separator inner cone and a plurality of grinding rollers disposed inside the coal mill cylinder body. The coal mill cylinder body has an input end and an output end, wherein:

[0010] The input end of the coal mill cylinder body is provided with a primary air inlet and a primary air chamber communicated with the primary air inlet. The grinding rollers are located on one side of the coal mill cylinder body close to the primary air chamber;

[0011] The output end of the coal mill cylinder body is provided with a plurality of powder conveying pipes. The separator inner cone is located on one side of the coal mill cylinder body close to the powder conveying pipes. There is a spacing between the separator inner cone and the inner wall of the coal mill cylinder body for accommodating the arched flow guiding device.

[0012] The present utility model discloses an arched flow guiding device, which includes a plurality of arched blocks, wherein:

[0013] Each arched block is arranged at equal intervals along the circumferential direction of the inner wall of the coal mill cylinder body, and each arched block is fixedly connected with the coal mill cylinder body;

[0014] The relative height of each arched block relative to the primary air chamber is the same as the relative height of the open end of the separator inner cone relative to the primary air chamber.

[0015] The present utility model discloses a coal mill, which includes a coal mill cylinder body, a separator inner cone and a plurality of grinding rollers disposed inside the coal mill cylinder body. The coal mill cylinder body has an input end and an output end, wherein:

[0016] The input end of the coal mill cylinder body is provided with a primary air inlet and a primary air chamber communicated with the primary air inlet. The grinding rollers are located on one side of the coal mill cylinder body close to the primary air chamber;

[0017] The output end of the coal mill cylinder is provided with a plurality of powder conveying pipes. The inner cone of the separator is located on one side of the coal mill cylinder close to the powder conveying pipes. There is a spacing between the inner cone of the separator and the inner wall of the coal mill cylinder for accommodating the arched flow guiding device. The arched flow guiding device includes a number of arched blocks, where:

[0018] Each arched block is arranged at equal intervals along the circumferential direction of the inner wall of the coal mill cylinder, and each arched block is fixedly connected to the coal mill cylinder;

[0019] The relative height of each arched block relative to the primary air chamber is the same as the relative height of the open end of the inner cone of the separator relative to the primary air chamber.

[0020] As a further preferred technical solution of the above technical solution, one end of the powder conveying pipe is inserted into the inner cone of the separator until the tapered end of the inner cone of the separator, and the other end of the powder conveying pipe extends out from the open end of the inner cone of the separator.

[0021] As a further preferred technical solution of the above technical solution, the arched block is of a hollow structure. The arched block has a semi-circular top surface, a semi-cylindrical surface and a semi-conical surface. The upper part of the semi-cylindrical surface is connected to the semi-circular top surface, and the lower part of the semi-cylindrical surface is connected to the semi-conical surface.

[0022] As a further preferred technical solution of the above technical solution, the radius of the semi-circular top surface is 200 mm; the height of the semi-cylindrical surface is 300 mm; the radius of the semi-cylindrical surface is 200 mm; the height of the semi-conical surface is 200 mm; the radius of the semi-conical surface is 200 mm.

[0023] As a further preferred technical solution of the above technical solution, the number of arched blocks of the arched flow guiding device is 12.

[0024] For the coal mill disclosed by the present utility model, its beneficial effect is that at the input end of the coal mill, the primary air flowing in from the primary air inlet passes through the primary air chamber, moves upward through the grinding roller area, reaches near the output end of the coal mill, and the primary air is redistributed. The uniform pulverized coal air flow enters the interior of the open end of the inner cone of the separator and flows until it flows out of the coal mill through the powder conveying pipe at the tapered end of the inner cone of the separator. Description of the Drawings

[0025] Figure 1 is the three-dimensional view of the present application.

[0026] Figure 2 is the front view of the present application.

[0027] Figure 3 is the right view of the present application.

[0028] Figure 4 is along Figure 3 the sectional view taken along the AA direction in

[0029] Figure 5 It is a schematic structural diagram of an arched diversion device and an arched block.

[0030] The reference numerals include:

[0031] 1 - powder conveying pipe; 2 - arched diversion device; 3 - mill housing; 4 - inner cone of separator; 5 - grinding roller; 6 - primary air chamber; 7 - primary air inlet; 8 - semi - circular top surface; 9 - semi - cylindrical surface; 10 - semi - conical surface; 100 - arched block; 200 - mill. Specific embodiments

[0032] The present utility model discloses a mill. The following combines with the preferred embodiment (Embodiment 1) and refers to the Figures 1-5 accompanying drawings to further describe the specific embodiments of the present utility model.

[0033] Embodiment 1 (only the mill 200).

[0034] Preferably, the mill 200 includes a mill housing 3 and an inner cone of separator 4 and a plurality of grinding rollers 5 disposed inside the mill housing 3. The mill housing 3 has an input end and an output end, wherein:

[0035] The input end of the mill housing 3 is provided with a primary air inlet 7 and a primary air chamber 6 communicated with the primary air inlet 7. The grinding rollers 5 are located on one side of the mill housing 3 close to the primary air chamber 6 (i.e., the output end);

[0036] The output end of the mill housing 3 is provided with a plurality of powder conveying pipes 1. The inner cone of separator 4 is located on one side of the mill housing 3 close to the powder conveying pipes 1 (i.e., the input end). There is a gap between the inner cone of separator 4 and the inner wall of the mill housing 3 for accommodating the arched diversion device 2.

[0037] Among them, the number of the powder conveying pipes 1 is preferably 4.

[0038] Among them, the number of the grinding rollers 5 is preferably 3.

[0039] Among them, one end of the powder conveying pipe 1 is inserted into the inner cone of separator 4 until the tip of the inner cone of separator 4, and the other end of the powder conveying pipe 1 extends out from the open end of the inner cone of separator 4.

[0040] Among them, the included angle between adjacent grinding rollers 5 is 120° (all located in the radial direction of the mill housing 3 or relative to the radial direction of the mill housing 3).

[0041] Among them, the mill housing 3, the primary air chamber 6 and the inner cone of separator 4 are coaxially arranged.

[0042] The working process of the mill in this embodiment is described below.

[0043] Specifically, at the input end of the coal mill 200, the primary air flowing in through the primary air inlet 7 passes through the primary air chamber 6, moves upward through the area of the grinding rollers 5, reaches near the output end of the coal mill 200, and the uneven pulverized coal air flow enters the inner cone 4 of the separator and flows inside the open end until it flows out of the coal mill through the powder conveying pipe 1 at the tapered end of the inner cone 4 of the separator.

[0044] Embodiment 2 (arched flow guiding device and coal mill including the arched flow guiding device).

[0045] Based on Embodiment 1, Embodiment 2 includes the following technical solutions.

[0046] Preferably, the arched flow guiding device 2 includes a number of (identical) arched blocks 100, each arched block 100 is arranged at equal intervals circumferentially along the inner wall of the coal mill cylinder 3, and each arched block 100 is fixedly connected to the inner wall of the coal mill cylinder 3 so as to surround the inner wall of the coal mill cylinder 3 for one week;

[0047] The relative height of each arched block 100 with respect to the primary air chamber 6 is the same as the relative height of the open end of the inner cone 4 of the separator with respect to the primary air chamber 6.

[0048] Among them, the arched block 100 is a hollow structure, the arched block 100 has a semi-circular top surface 8, a semi-cylindrical surface 9 and a semi-conical surface 10. The upper part of the semi-cylindrical surface 9 is connected to the semi-circular top surface 8, and the lower part of the semi-cylindrical surface 9 is connected to the semi-conical surface 10, which does not hinder the pulverized coal air flow from flowing towards the open end of the inner cone 4 of the separator and ensures a good adjustment effect on the wind direction and air volume.

[0049] Among them, the wall thickness of the arched block 100 is 15 mm, which ensures the strength and service life of the arched flow guiding device 2.

[0050] Among them, the radius of the semi-circular top surface 8 is 200 mm.

[0051] Among them, the height of the semi-cylindrical surface 9 is 300 mm.

[0052] Among them, the radius of the semi-cylindrical surface 9 is 200 mm.

[0053] Among them, the height of the semi-conical surface 10 is 200 mm.

[0054] Among them, the radius of the semi-conical surface 10 is 200 mm.

[0055] Among them, the number of the arched blocks 100 of the arched flow guiding device 2 is preferably 12.

[0056] Among them, the arched block 100 is made of (high wear-resistant) alloy steel material to ensure its service life and provide a guiding effect for a long time.

[0057] Among them, each arched block 100 is fixedly connected to the inner wall of the coal mill cylinder body 3, preferably by welding.

[0058] The working process of the coal mill including the arched flow guiding device in this embodiment is described below.

[0059] Specifically, at the input end of the coal mill 200, the primary air flowing in from the primary air inlet 7 passes through the primary air chamber 6, moves upward through the roller 5 area, reaches near the output end of the coal mill 200, and the primary air is redistributed. The uniform pulverized coal air flow enters the open end of the inner cone 4 of the separator and flows inside until the tip of the inner cone 4 of the separator flows out of the coal mill through the powder conveying pipe 1.

[0060] Embodiment 3 (only the arched flow guiding device 2).

[0061] Preferably, the arched flow guiding device 2 includes a plurality of (identical) arched blocks 100.

[0062] Among them, the arched block 100 is a hollow structure. The arched block 100 has a semi-circular top surface 8, a semi-cylindrical surface 9 and a semi-conical surface 10. The upper part of the semi-cylindrical surface 9 is connected to the semi-circular top surface 8, and the lower part of the semi-cylindrical surface 9 is connected to the semi-conical surface 10.

[0063] Among them, the wall thickness of the arched block 100 is 15 mm, ensuring the strength and service life of the arched flow guiding device 2.

[0064] Among them, the radius of the semi-circular top surface 8 is 200 mm.

[0065] Among them, the height of the semi-cylindrical surface 9 is 300 mm.

[0066] Among them, the radius of the semi-cylindrical surface 9 is 200 mm.

[0067] Among them, the height of the semi-conical surface 10 is 200 mm.

[0068] Among them, the radius of the semi-conical surface 10 is 200 mm.

[0069] Among them, the number of arched blocks 100 of the arched flow guiding device 2 is preferably 12.

[0070] Among them, the arched block 100 is made of (high wear-resistant) alloy steel material to ensure its service life and provide a flow guiding effect for a long time.

[0071] It is worth mentioning that the specific components and processing techniques of the alloy steel materials involved in the patent application for the present utility model should be regarded as prior art. For the specific structures, working principles, control methods, and spatial layout methods that may be involved in these technical features, conventional selections in the art can be adopted and should not be regarded as the inventive points of the patent for the present utility model. The patent for the present utility model will not be further elaborated in detail.

[0072] For those skilled in the art, it is still possible to modify the technical solutions described in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. Coal mill, characterized in that, It includes a coal mill cylinder body, a separator inner cone disposed inside the coal mill cylinder body, and a plurality of grinding rollers. The coal mill cylinder body has an input end and an output end, wherein: The input end of the coal mill cylinder body is provided with a primary air inlet and a primary air chamber communicated with the primary air inlet. The grinding rollers are located on one side of the coal mill cylinder body close to the primary air chamber; The output end of the coal mill cylinder body is provided with a plurality of powder conveying pipes. The separator inner cone is located on one side of the coal mill cylinder body close to the powder conveying pipes. There is a spacing between the separator inner cone and the inner wall of the coal mill cylinder body for accommodating an arched guiding device. The arched guiding device includes a plurality of arched blocks, wherein: Each arched block is arranged at equal intervals along the circumferential direction of the inner wall of the coal mill cylinder body, and each arched block is fixedly connected to the coal mill cylinder body; The relative height of each arched block relative to the primary air chamber is the same as the relative height of the open end of the separator inner cone relative to the primary air chamber; The arched block is a hollow structure. The arched block has a semi-circular top surface, a semi-cylindrical surface, and a semi-conical surface. The upper part of the semi-cylindrical surface is connected to the semi-circular top surface, and the lower part of the semi-cylindrical surface is connected to the semi-conical surface; The arched block is made of alloy steel material.

2. The coal mill according to claim 1, characterized in that, The radius of the semi-circular top surface is 200 mm; the height of the semi-cylindrical surface is 300 mm; the radius of the semi-cylindrical surface is 200 mm; the height of the semi-conical surface is 200 mm; the radius of the semi-conical surface is 200 mm.

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