Coal mill structure with optimized energy efficiency

Abstract

The utility model discloses a coal mill structure with optimized energy efficiency. The coal mill structure comprises a nozzle static ring, the nozzle moving rings are distributed on the outer circumference of the millstone tile; the nozzle static ring is arranged on the outer circumference of the nozzle moving ring in a sleeving mode, and the nozzle static ring is integrally cast in a layered mode and specifically comprises an upper guiding cone (a high-temperature sealing body) which is sectioned in a geometric radian mode and a lower sealing body which is divided into four sections. According to the coal mill structure with the optimized energy efficiency, the roller sleeve, the lining plate and the movable and static rings of the coal mill are replaced by the novel metal ceramic composite roller sleeve, the lining plate and the metal ceramic movable and static rings, so that the aims of improving the output of the coal mill, prolonging the service life of a milling piece and reducing the power consumption are fulfilled, the internal flow field of the coal mill is more reasonable and effective, and the energy efficiency is improved. Air leakage of primary air is reduced, pulverized coal is more effectively conveyed to a grinding area through airflow, and the output of the coal mill is improved. The sealing structure of the movable ring and the static ring is firmer in connection, can guarantee a gap between the movable ring and the static ring for a long time, guarantees efficient utilization of primary air, and can carry and dry pulverized coal more effectively.

Description

Technical Field

[0001] This utility model relates to the field of coal mill technology, and more specifically to a coal mill structure with optimized energy efficiency. Background Technology

[0002] With changes in the supply and demand relationship of thermal coal, the price of thermal coal has continued to rise, and the supply is tight. In order to reduce power generation costs, power plants have been blending low-quality coal in large quantities, which has reduced the grindability of the coal. As the units operate, the roller sleeves, liners, and dynamic and static rings wear down continuously, requiring periodic replacement (or welding treatment). To address this problem, old roller sleeves are welded, but the performance after welding is also poor, and cracking is prone to occur. The roller sleeves can only guarantee normal output for 6,000 hours. After three welding treatments, the grinding rollers are prone to cracking and becoming unusable. After online welding, the external dimensions cannot be well matched with the external dimensions of the grinding disc, and after wear, large ripples and furrows (grooves of about 30mm are formed between the rollers and the bearings) appear, causing the coal bed shape to not be well maintained, resulting in serious over-grinding, which leads to reduced coal grinding output and increased power consumption.

[0003] The nozzle ring has a short service life and the air passage profile is severely worn, which cannot effectively organize the flow field. The turbulent flow field leads to a decrease in air supply efficiency, and it is necessary to increase the air volume to maintain the operating output. The coarse coal powder particles travel back and forth between the grinding disc and the separator baffle more, and the circulation ratio increases. The qualified coal powder cannot be discharged in time, which increases the resistance of the coal mill body, as well as the power consumption of the coal mill and the wear of components such as grinding roller sleeves, liners, cylinder, and separator cone.

[0004] The original nozzle moving and stationary rings were designed with ZG50Mn2 or steel plate structural components. Due to the harsh working environment inside the mill, the high-speed blowing of the primary air caused severe wear on the nozzle rings, resulting in turbulent flow inside the mill cylinder. The primary air also severely damaged the grinding rollers and roller frame, causing furrows in some areas. Simultaneously, the wear of the nozzle rings increased the flow area, significantly reducing the ventilation output of the coal mill. This led to increased slag discharge from the on-site slag box, which, once it reached a certain level, caused blockage of the air inlet, rendering the equipment inoperable.

[0005] Therefore, how to provide an energy-efficient coal mill structure that extends the service life of grinding parts, reduces power consumption, makes the internal flow field of the coal mill more reasonable and effective, reduces primary air leakage, and more effectively transports coal powder to the grinding area to improve the output of the coal mill is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0006] In view of this, the present invention provides a coal mill structure with optimized energy efficiency.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] This utility model discloses an energy-efficient optimized coal mill structure, including a stationary nozzle ring and a rotating nozzle ring distributed on the outer circumference of the grinding disc.

[0009] The nozzle stationary ring is fitted around the outer circumference of the nozzle moving ring. The nozzle stationary ring is a layered integral casting, specifically including an upper guide cone (high-temperature sealing body) and a lower sealing body. The upper guide cone (high-temperature sealing body) is segmented by geometric arc, and the lower sealing body is divided into four segments.

[0010] Preferably, the nozzle stationary ring has a split structure, and the main wear parts are made of high-chromium metal ceramic.

[0011] Preferably, the upper half of the nozzle stationary ring is widened laterally, specifically, the upper guide cone (high-temperature sealing body) extends outward to the throat of the nozzle moving ring.

[0012] Preferably, the outer rings of the nozzle moving ring blades are closed and connected.

[0013] Preferably, the nozzle moving ring throat blade is integrally cast from alloy ceramic.

[0014] Preferably, a material-blocking ring is added to the nozzle moving ring pressure plate.

[0015] As can be seen from the above technical solution, compared with the prior art, this utility model discloses an energy-optimized coal mill structure. By replacing the coal mill roller sleeves, liners, and dynamic and static rings with new metal-ceramic composite roller sleeves, liners, and metal-ceramic dynamic and static rings, it achieves the purpose of increasing coal mill output, extending the service life of grinding parts, and reducing power consumption. The internal flow field of the coal mill is more rational and effective, primary air leakage is reduced, and the airflow more effectively transports coal powder to the grinding area, increasing the coal mill output. The sealing structure of the dynamic and static rings is more robust, ensuring the long-term maintenance of the dynamic and static ring gap and guaranteeing efficient utilization of primary air, thus more effectively carrying and drying coal powder. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 The attached figure is a schematic diagram of the main planar structure of this utility model. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] The present invention provides an energy-efficient optimized coal mill structure, comprising a nozzle stationary ring and a nozzle moving ring 2 distributed on the outer circumference of the grinding disc 8;

[0020] The nozzle stationary ring is fitted around the outer circumference of the nozzle moving ring. The nozzle stationary ring is a layered integral casting, specifically including an upper guide cone (high temperature sealing body) 1 and a lower sealing body 3. The upper guide cone (high temperature sealing body) 1 is segmented by geometric arc, and the lower sealing body 3 is divided into four segments.

[0021] The nozzle stationary ring has a split structure, with the main wear parts made of high-chromium cermet cast in one piece. Surface spraying is not permitted, and the ceramic layer is not allowed to be formed by powder metallurgy pressing, inlaying, casting, or bonding. The upper half of the nozzle stationary ring is widened laterally, specifically by the upper guide cone (high-temperature sealing body) 1 extending outward to the throat of the nozzle moving ring 2. This is to block the vertical gap between the nozzle moving and stationary air rings, preventing foreign objects from falling through the gap and causing severe friction and jamming.

[0022] The nozzle moving ring 2 is also designed as a split structure. The base of the nozzle moving ring 2 is integrally cast using ZG50Mn2. The outer rings of the nozzle moving ring 2 blades are closed and connected. The most wear-prone area of ​​the throat is treated with a metal-ceramic alloy for wear resistance, which greatly increases its resistance to abrasive wear and wind damage. Furthermore, the throat blades are integrally cast using alloy ceramic, and high-quality streamlined throat blades must be cast. Since the throat of the nozzle moving ring is a coexisting area of ​​wind and coal, the wear rate at the throat of the nozzle moving ring will be accelerated by the wind damage from the primary air and the intense collision of falling stones and coal. Therefore, a high-chromium ceramic wear-resistant layer must be added to the most wear-prone area of ​​the throat to reduce the wear of the nozzle moving ring throat by the primary air and stones and coal. Furthermore, the upper half of the nozzle stationary ring is widened laterally to cover the gap between the nozzle moving and stationary rings, so that falling stones, coal or iron pieces will not be trapped between the nozzle moving ring and the nozzle stationary ring. The gap between the nozzle moving and stationary rings after assembly is about 10mm.

[0023] The metal-ceramic alloy has a Rockwell hardness of HRC60-62. The high-chromium metal ceramic has higher wear resistance than ordinary high-chromium and cast steel materials, and its service life is greatly increased, reaching 3-4 times or more than that of cast alloy steel. This significantly reduces the workload of coal mill maintenance and greatly reduces maintenance costs.

[0024] The addition of a material-blocking ring 6 to the pressure plate 5 of the nozzle moving ring 2 significantly increases the connection stability between the nozzle moving ring 2 and the grinding disc 8. This prevents the nozzle moving ring 2 from detaching during mill operation and vibrations. It also increases the thickness of the coal bed in the mill's grinding area, thereby reducing mill vibration, minimizing impact wear between the roller sleeve and the liner, reducing the discharge of coke and stone, and reducing wear on the nozzle moving ring throat. Furthermore, the roller surface becomes smoother and free of ripples after roller sleeve wear, reducing the difficulty of welding. The bottom of the nozzle moving ring 2 is welded to the grinding disc 8 using a support plate 7, ensuring that the stability of the nozzle moving ring and the support plate remains unaffected during operation.

[0025] The grinding components in the coal mill structure are specifically a combination of grinding rollers 9 and liners. Further use of metal-ceramic composite materials can increase the grinding area, improve grinding output, and thus improve mill efficiency. Due to the different wear resistance properties of ceramics and high chromium, there is a height difference on the surface, which forms a honeycomb structure. This structure not only increases the friction of the grinding roller and liner surface and the effective grinding area, but also reduces the relative sliding of materials between the grinding roller and the liner. During the service life, it can better maintain the original smooth appearance of the roller sleeve and liner, allowing the grinding roller and liner to fit better during operation, which helps to improve grinding efficiency and reduce the unit consumption of the coal mill.

[0026] This utility model presents an energy-optimized coal mill structure. By replacing the coal mill roller sleeves, liners, and dynamic and static rings with novel metal-ceramic composite roller sleeves, liners, and metal-ceramic dynamic and static rings, it achieves the goals of increasing coal mill output, extending the service life of grinding components, and reducing power consumption. The internal flow field of the coal mill is more rational and effective, primary air leakage is reduced, and the airflow more effectively transports pulverized coal to the grinding area, increasing the coal mill output. The sealing structure of the dynamic and static rings is more robust, ensuring a long-term maintenance of the dynamic and static ring gap and guaranteeing efficient utilization of primary air, thus more effectively carrying and drying pulverized coal.

[0027] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An energy efficient mill structure, characterized by, It includes: A nozzle static ring; A nozzle dynamic ring (2) distributed on the outer circumference of the mill tile (8); The nozzle static ring is sleeved on the outer circumference of the nozzle dynamic ring, and is integrally cast in layers, specifically including an upper guide cone (high temperature sealing body) (1) and a lower sealing body (3), wherein the upper guide cone (high temperature sealing body) (1) is segmented in geometric radian, and the lower sealing body (3) is segmented into four parts.

2. The energy efficient mill structure as claimed in claim 1, wherein, The nozzle static ring is of split structure, and the material of the main wear part is high chromium metal ceramic.

3. The energy efficiency optimized coal pulverizer structure as claimed in claim 2 wherein, The upper half of the nozzle static ring is widened transversely, specifically that the upper guide cone (high temperature sealing body) (1) extends outward to the throat of the nozzle dynamic ring (2).

4. The energy efficiency optimized coal pulverizer structure as claimed in claim 1, wherein, The outer circle of the nozzle dynamic ring (2) blade is closed and connected.

5. The energy efficiency optimized coal pulverizer structure as claimed in claim 4, wherein, The nozzle dynamic ring (2) throat blade is integrally cast by alloy ceramic.

6. The energy efficiency optimized coal pulverizer structure as claimed in claim 1, wherein, The nozzle dynamic ring (2) pressing plate (5) is additionally provided with a material blocking ring (6).

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