A preheating grinding device for pulverized coal of a coal-fired boiler

Abstract

The utility model provides a kind of preheating grinding device for coal powder of coal-fired boiler, it is related to boiler coal coal powder combustion technical field, it includes: the box with feed inlet, discharge gate and air inlet, the lateral wall surface of box is equipped with transition chamber;The outer top of box is equipped with motor, the output end of motor is equipped with rotating rod, the other end of rotating rod extends to the inside of box;Main grinding block, it is located on the outer wall surface of rotating rod, multiple grinding grooves are opened in the circumferential direction on the outer wall surface of main grinding block;Multiple first lugs are equipped on the outer wall surface of main grinding block;Multiple vice grinding blocks are respectively equipped on the inner wall surface of box, and vice grinding block and grinding groove one-to-one correspond;Multiple second lugs are equipped on the outer wall surface of each vice grinding block;Gas outlet passage is opened in the inside of each vice grinding block and is communicated with transition chamber, multiple gas outlets are opened on the outer wall surface of each vice grinding block, the device can preheat and simultaneously carry out grinding treatment to coal powder, to improve the pyrolysis rate of coal powder.

Description

Technical Field

[0001] This utility model relates to the field of boiler coal pulverized coal combustion technology, specifically to a preheating and grinding device for coal pulverized coal in coal-fired boilers. Background Technology

[0002] Currently, pulverized coal in boilers produces nitrogen oxides during combustion. These nitrogen oxide emissions are harmful to human health, necessitating optimization of the pulverized coal combustion process to reduce nitrogen oxide generation and emissions. In the initial stage of pulverized coal combustion in boilers, the coal entering the furnace is typically at ambient temperature (25–50°C). Due to the relatively low temperature, the pyrolysis time during combustion is short, resulting in delayed volatile matter release. Furthermore, uneven coal particle size also leads to variations in pyrolysis rates; coarse particles (>80μm) undergo incomplete pyrolysis, resulting in a higher proportion of residual coke nitrogen. Utility Model Content

[0003] This invention addresses the problem of slow pyrolysis of pulverized coal when it is not preheated in the initial stage of combustion or when it is pulverized into small particles. It provides a preheating and grinding device for pulverized coal in coal-fired boilers, which can preheat and grind pulverized coal simultaneously, thereby improving the pyrolysis rate of pulverized coal.

[0004] The technical solution adopted in this utility model is:

[0005] A preheating and grinding device for pulverized coal in a coal-fired boiler is provided, comprising:

[0006] The box has a feed inlet, a discharge outlet and an air inlet, and a transition cavity is opened inside the side wall of the box.

[0007] The motor is located on the top of the housing, and a rotating rod is provided on the output end of the motor. The other end of the rotating rod passes through the top of the housing and extends into the interior of the housing.

[0008] The main grinding block is located on the outer wall of the rotating rod. Multiple grinding grooves are circumferentially formed on the outer wall of the main grinding block with the central axis of the rotating rod as the rotation axis. Multiple first protrusions are provided on the inner wall of each grinding groove of the main grinding block.

[0009] Multiple auxiliary grinding blocks are respectively disposed on the inner wall surface of the housing, and each auxiliary grinding block corresponds to each grinding groove; multiple second protrusions are provided on the outer wall surface of each auxiliary grinding block; an air outlet channel communicating with the transition cavity is opened inside each auxiliary grinding block, and multiple air outlets communicating with the corresponding air outlet channel are opened on the outer wall surface of each auxiliary grinding block.

[0010] Optionally, the top of the box is provided with a feed pipe that communicates with the feed inlet, and the side wall of the box is provided with an air inlet that communicates with the air inlet; the feed pipe passes through the side wall of the air inlet and extends into the interior of the air inlet, so that the feed pipe and the air inlet form a sleeve.

[0011] Optionally, the inner wall surface of the main grinding block in each grinding groove and the outer wall surface of the auxiliary grinding block in each grinding groove have a grinding gap, and the grinding gap decreases along the direction of coal powder movement.

[0012] Optionally, the gap between each first bump and each corresponding second bump is 70–90 μm.

[0013] Optionally, the connecting surface of the housing between two adjacent sub-grinding blocks is an arc surface, and the notch faces the outer wall surface of the main grinding block.

[0014] Optionally, the cross-section of the main grinding block located between two adjacent grinding grooves is trapezoidal, and the cross-section of each auxiliary grinding block is trapezoidal.

[0015] Optionally, the connection between each first protrusion and the outer wall of the main grinding block is a curved surface, and the connection between each second protrusion and the outer wall of the auxiliary grinding block is a curved surface.

[0016] Optionally, the air outlet direction of each air outlet is opposite to the rotation direction of the main grinding block.

[0017] The beneficial effects of this utility model are:

[0018] 1. By setting up a box, pulverized coal is fed into the box through the feed inlet. At the same time, hot air is introduced into the box through the air inlet. The pulverized coal inside the box falls due to its own weight until it falls onto the main grinding block. At this point, the main grinding block rotates under the drive of the motor. When the main grinding block rotates, it throws out the pulverized coal on its surface. The thrown-out pulverized coal enters between each auxiliary grinding block and the main grinding block. Then, multiple first protrusions on the outer wall of the main grinding block and multiple second protrusions on each auxiliary grinding block grind the pulverized coal, thereby increasing the pyrolysis rate of the pulverized coal.

[0019] 2. Heat-containing gas is introduced into the chamber through the air inlet. This gas passes through the transition chamber and enters the air outlet channel inside each auxiliary grinding block. Finally, it is discharged through multiple air outlets connected to the corresponding air outlet channels. The discharged high-heat gas can heat the coal powder during grinding, so that the coal powder discharged after grinding has a certain temperature, thereby increasing the pyrolysis rate of the coal powder. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the main structure of a preheating and grinding device for pulverized coal in a coal-fired boiler disclosed in this embodiment;

[0022] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle;

[0023] Figure 3 for Figure 1 A magnified view of a portion of point B in the middle.

[0024] Figure label:

[0025] 1-Box body, 10-Inlet, 11-Outlet, 12-Air inlet, 13-Transition chamber;

[0026] 2-Motor, 20-Rotating rod;

[0027] 3-Main grinding block, 30-First protrusion, 31-Grinding groove;

[0028] 4-Secondary grinding block, 40-Air outlet channel, 41-Air outlet, 42-Second protrusion;

[0029] 5-Grinding gap;

[0030] 6-Intake pipe;

[0031] 7-Feed pipe. Detailed Implementation

[0032] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0033] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0034] The embodiments of the utility model will now be described in detail with reference to the accompanying drawings.

[0035] Example

[0036] Please see Figure 1-3 As shown, this embodiment discloses a preheating and grinding device for filtering pulverized coal in coal combustion, including a housing 1. A motor 2 is installed on the top of the housing 1, and a rotating rod 20 is installed on the output end of the motor 2. The other end of the rotating rod 20 passes through the top of the housing 1 and extends into the interior of the housing 1, meaning that the motor 2 can drive the rotating rod 20 to rotate when it is running. A main grinding block 3 is installed on the outer wall of the rotating rod 20. Multiple grinding grooves 31 are opened on the outer wall of the main grinding block 3 about its own central axis. Multiple first protrusions 30 are installed on the inner wall of each grinding groove 31 of the main grinding block 3. There is a gap between adjacent first protrusions 30 for pulverized coal to pass through.

[0037] Furthermore, multiple auxiliary grinding blocks 4 are provided on the inner wall surface of the aforementioned housing 1. Each auxiliary grinding block 4 has a trapezoidal cross-section, and each auxiliary grinding block 4 corresponds to each grinding groove 31, meaning that the end of each auxiliary grinding block 4 extends into the interior of each corresponding grinding groove 31. Multiple second protrusions 42 are provided on the outer wall surface of each auxiliary grinding block 4, and there is also a gap between adjacent second protrusions 42 for coal powder to pass through. There is a grinding gap 5 between the inner wall surface of the main grinding block 3 located in the grinding groove 31 and the outer wall surface of the auxiliary grinding block 4 located in each grinding groove 31. This gap is not only used for the passage of coal powder, but also allows the main grinding block 3 to rotate during the passage of coal powder by rotating the rotating rod 20. When the main grinding block 3 rotates, it grinds the coal powder located between the main grinding block 3 and the auxiliary grinding blocks 4, grinding the larger coal powder into smaller coal powder.

[0038] Furthermore, in this embodiment, the inner diameter of the grinding gap 5 gradually decreases along the direction of coal powder movement. This means that different particle sizes of coal powder enter the housing 1 through the feed inlet 10. Larger particle sizes require a slightly larger inner diameter grinding gap 5 to enter and be ground by the multiple first protrusions 30 and multiple second protrusions 42. This ensures that coal powder of different sizes can be ground into appropriately sized particles within the grinding gap 5 between the main grinding block 3 and the multiple auxiliary grinding blocks 4. In addition, the shortest distance between the first protrusion 30 and the second protrusion 42 in this embodiment is 70–90 μm.

[0039] A feed pipe is installed on the top of the aforementioned housing 1. One end of the feed pipe is connected to the feed inlet 10, and the other end is connected to the pulverized coal conveying end, allowing the pulverized coal to be conveyed into the housing 1 through the feed pipe. An air inlet pipe 6 is installed on the outer wall of the aforementioned housing 1. One end of the air inlet pipe 6 is connected to the air inlet 12, and the other end is connected to the gas conveying end, allowing high-heat gas to be conveyed into the housing 1 through the air inlet pipe 6 and preheating the pulverized coal inside the housing 1. The aforementioned feed pipe penetrates the side wall of the air inlet pipe 6 and extends into the interior of the air inlet pipe 6, forming a sleeve between the feed pipe and the air inlet pipe 6. The section of the feed pipe inside the air inlet pipe 6 is coaxially arranged with the air inlet pipe 6, and the direction of movement of the pulverized coal in the feed pipe is opposite to the direction of movement of the gas in the air inlet pipe 6. During this process, the heat contained in the gas will undergo preheating treatment with the pulverized coal, so that some of the heat in the gas will preheat the pulverized coal entering the housing 1. It is worth noting that in this embodiment, the gas containing heat flowing in the intake pipe 6 can be the recovered exhaust heat, achieving the effect of reuse.

[0040] The connecting surface between two adjacent auxiliary grinding blocks 4 in the aforementioned box 1 is an arc surface, and the concave part of the arc surface faces the main grinding block 3. That is, after the coal powder is ground through the grinding gap 5 between the main grinding block 3 and the auxiliary grinding block 4, the coal powder is thrown out by the rotating main grinding block 3. The thrown coal powder will be scattered towards the connection between adjacent auxiliary grinding blocks 4 in the box 1. After the scattered coal powder hits the inner wall of the box 1, the particle size of the coal powder will also change. The arc surface setting can increase the rolling speed of the coal powder towards the next grinding gap 5 when it falls onto the arc surface after collision, so that it can quickly enter the grinding gap 5 for grinding.

[0041] The connection between each first protrusion 30 and the main grinding block 3 is a curved surface, and the connection between each second protrusion 42 and the auxiliary grinding block 4 is also a curved surface. The curved surface facilitates the movement of coal powder. In addition, the gas exits through each outlet 41 in the opposite direction to the rotation direction of the main grinding block 3, so that the high-heat gas can collide with the coal powder on the main grinding block 3 when it is discharged through the outlet 41, resulting in a better preheating effect on the coal powder.

[0042] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Without conflict, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preheating and grinding device for pulverized coal in a coal-fired boiler, characterized in that, include: The housing has a feed inlet, a discharge outlet and an air inlet, and a transition cavity is provided inside the side wall of the housing. A motor is located on the outer top of the housing, and a rotating rod is provided on the output end of the motor. The other end of the rotating rod passes through the top of the housing and extends into the interior of the housing. The main grinding block is disposed on the outer wall surface of the rotating rod, and multiple grinding grooves are circumferentially formed on the outer wall surface of the main grinding block with the central axis of the rotating rod as the rotation axis; multiple first protrusions are provided on the inner wall surface of each grinding groove of the main grinding block; Multiple auxiliary grinding blocks are respectively disposed on the inner wall surface of the housing, and each auxiliary grinding block corresponds to each grinding groove; multiple second protrusions are provided on the outer wall surface of each auxiliary grinding block; an air outlet channel communicating with the transition cavity is opened inside each auxiliary grinding block, and multiple air outlets communicating with the corresponding air outlet channel are opened on the outer wall surface of each auxiliary grinding block.

2. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 1, characterized in that, The top of the box is provided with a feed pipe that communicates with the feed inlet, and the side wall of the box is provided with an air inlet that communicates with the air inlet; the feed pipe passes through the side wall of the air inlet and extends into the interior of the air inlet, so that the feed pipe and the air inlet form a sleeve.

3. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 2, characterized in that, The main grinding block has a grinding gap between its inner wall surface in each grinding groove and the outer wall surface of the auxiliary grinding block in each grinding groove, and the grinding gap decreases along the direction of coal powder movement.

4. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 3, characterized in that, The gap between each of the first bumps and each corresponding second bump is 70–90 μm.

5. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 1, characterized in that, The connecting surface of the housing between two adjacent auxiliary grinding blocks is an arc surface, and the notch faces the outer wall surface of the main grinding block.

6. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 1, characterized in that, The main grinding block has a trapezoidal cross-section located between two adjacent grinding grooves, and each of the secondary grinding blocks has a trapezoidal cross-section.

7. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 1, characterized in that, The connection between each first protrusion and the outer wall surface of the main grinding block is a curved surface, and the connection between each second protrusion and the outer wall surface of the auxiliary grinding block is a curved surface.

8. The preheating and grinding device for pulverized coal in a coal-fired boiler according to claim 1, characterized in that, The air outlet direction of each of the air outlets is opposite to the rotation direction of the main grinding block.

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