Efficient centrifugal pulverized coal selecting device and method thereof

Abstract

The invention relates to the technical field of pulverized coal selecting devices, and discloses an efficient centrifugal pulverized coal selecting device and a method thereof.The efficient centrifugal pulverized coal selecting device comprises a third separator shell, and a second separator shell is installed at the top end of the third separator shell. According to the efficient centrifugal pulverized coal selecting device and method, under the same primary air flow working condition, when the efficient centrifugal pulverized coal selecting device is adopted, the internal flow field of a coal mill is uniform, the flow speed is not larger than 10 m / s, and resistance is small. A rotor of a traditional dynamic powder selecting device serves as a resistance belt, the internal resistance is large, the peripheral flow speed is about 20 m / s, and abrasion is extremely large. According to the efficient centrifugal powder selecting device, an air suction type rotor with arc-shaped bionic blades is adopted, drainage is achieved through a wing-shaped front guide device, air suction is forcibly conducted below the rotor, and the efficient centrifugal powder selecting device faces a larger ascending air powder section below; a rotor of a traditional dynamic powder selecting device rotates to form a resistance belt, an air inlet channel and a coarse powder discharging channel of the traditional dynamic powder selecting device coincide in the annular peripheral area of the rotor in a hedging mode, and therefore the volume strength of the efficient centrifugal powder selecting device is much larger than that of the traditional powder selecting device.

Description

Technical Field

[0001] The invention relates to the technical field of coal powder selection devices, and in particular to a high-efficiency centrifugal coal powder selection device and a method thereof. Background Art

[0002] The coal mill is the most important auxiliary machine in the boiler pulverizing system. It is responsible for grinding the raw coal into coal powder of qualified fineness and blowing it into the boiler for combustion. The coal mill pulverizer selection device, as the pulverizing system's pulverizing device, determines the fineness and uniformity of the coal powder delivered by the coal mill, and directly affects the combustion effect, fly ash and coarse slag of the boiler.

[0003] How to effectively improve the unit efficiency and reduce the coal consumption for power generation based on the existing equipment has become a key issue restricting the realization of energy conservation, emission reduction and sustainable development in thermal power plants. Secondly, many medium-speed coal mills equipped in thermal power units across the country have been in operation for a long time, or have been poorly maintained or have backward technology, and generally have problems such as insufficient mill output; coarse coal powder fineness, poor uniformity, small fineness adjustment range, high unit pulverizing power consumption, high ventilation power consumption and large stone coal emissions. Summary of the invention

[0004] The object of the present invention is to provide a high-efficiency centrifugal coal powder selection device and method thereof to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a high-efficiency centrifugal coal powder selection device and method thereof, comprising a separator housing three, a separator housing two being installed at the top of the separator housing three; A ceramic fiber twisted rope is installed at the bottom end of the separator shell three, a return hopper is arranged at the top of the separator shell three, a forced suction type bionic blade is installed inside the separator shell two, a static blade is installed inside the separator shell two, a connecting pipe is installed on the inner side of the forced suction type bionic blade, a separator shell one is installed at the top end of the separator shell two, a powder outlet pipe bottom flange is installed at the top end of the separator shell one, a powder outlet pipe is installed at the top end of the powder outlet pipe bottom flange, an upper cover is installed at the top of the connecting pipe, and a There is a pressure ring, an end cover is installed at the top of the upper cover, a coal drop pipe is installed at the top of the upper cover, a coal drop pipe short section is installed at the top of the coal drop pipe, a coal drop pipe flange is installed at the top of the coal drop pipe short section, a powder outlet pipe flange is installed at the top of the powder outlet pipe, a separator transmission part is installed on the outer wall of the upper cover, a belt guard is installed at the bottom of the separator transmission part, a variable frequency speed regulation three-phase asynchronous motor is installed at the bottom end of the belt guard, a support frame is installed at the bottom end of the separator transmission part, and a bracket is fixedly connected to the inner side of the variable frequency speed regulation three-phase asynchronous motor.

[0006] Preferably, a door cover is installed at the top of the separator housing 1, and a separator on-site terminal junction box is installed at the top of the separator housing 1.

[0007] Preferably, four powder outlet pipes are provided, and the four powder outlet pipes are respectively distributed in a circular array around the top end of the separator housing 1.

[0008] A method for high-efficiency centrifugal coal powder selection comprises the following steps: S1, customized design based on the coal mill conditions at the power plant, design a highly matched Laval flow field inside the centrifugal powder selection device, establish an isentropic flow model, improve the powder selection efficiency, reduce the reactive circulation of coal powder in the mill, and improve the output of the coal mill; S2, design an airfoil guide to initially separate and guide the coal powder and reduce the increase in resistance; S3, design a forced suction type bionic blade group to forcibly separate the coal powder, and avoid the unqualified coal powder being forcibly absorbed and transported; S4, using software simulation and repeated numerical calculations, ensures that the powder selection device has sufficient volumetric strength, maximum flow field matching, and can perform preliminary powder selection with low resistance and high efficiency.

[0009] Preferably, through the Laval flow field design, the airflow velocity distribution can be effectively adjusted to optimize the separation effect of coal powder particles. By establishing an isentropic flow model and simulating the flow state of gas under different conditions, the airflow parameters can be accurately controlled to achieve the best separation performance.

[0010] Preferably, computational fluid dynamics (CFD) software is used to simulate and analyze different airfoils, evaluate their flow field characteristics under actual working conditions, and conduct a comprehensive evaluation based on the two indicators of separation efficiency and drag loss. The designed airfoil guide is installed at the inlet of the powder selection device. Multiple airfoil guides should be evenly distributed on the inlet cross-section. A modular design method is adopted to facilitate later maintenance and adjustment, and high-strength and wear-resistant materials are used to manufacture the airfoil guide.

[0011] Preferably, a bionic blade shape suitable for airflow separation is selected, a streamlined design is adopted to ensure a smooth blade surface, the blade installation angle is adjusted according to actual working conditions to ensure that the airflow can flow smoothly along the blade surface, and high-strength, wear-resistant materials are selected.

[0012] Preferably, a three-dimensional model is established, and appropriate CFD software is selected to perform detailed flow field simulation, analyze the velocity distribution of the airflow, analyze the pressure distribution of the airflow, and simulate the movement trajectory of the coal powder particles in the airflow.

[0013] Preferably, the angle of the blades is adjusted to ensure smooth airflow and reduce resistance, the spacing between the blades is adjusted to ensure uniform airflow distribution and improve separation efficiency, and the geometric shape of the blades is optimized to make it more suitable for airflow separation.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: First, under the same primary air flow condition, when the present invention uses a high-efficiency centrifugal powder selection device, the internal flow field of the coal mill is uniform, the flow rate is no more than 10m / s, and the resistance is small. The rotor of the traditional dynamic powder selection device acts as a resistance belt, and its internal resistance is large. The flow rate around is about 20m / s, and the wear is extremely large. The high-efficiency centrifugal powder selection device adopts an air suction rotor with arc-shaped bionic blades, which is guided by an airfoil guide, and the air is forced to be sucked from the bottom of the rotor, facing a larger rising wind and powder section below; while the rotor of the traditional dynamic powder selection device rotates to form a resistance belt, and its air intake and coarse powder discharge channels overlap in the annular outer area of ​​the rotor. Therefore, the volumetric strength of the high-efficiency centrifugal powder selection device is much greater than that of the traditional powder selection device.

[0015] Secondly, after the high-efficiency centrifugal powder selection device of the present invention is connected to the coal mill, the coal powder in the action range is firstly taken into the rotor through the suction rotor of the coal mill through the guide, and then there is a secondary separation after entering the rotor. The coarse powder particles are ejected onto the outer wall of the powder selection device through the centrifugal action and fall to the grinding disc through the return cone to continue grinding, while the qualified fine powder enters the coal powder pipeline under the action of the airflow.

[0016] Third, when the rotation speed of the present invention is increased within an appropriate range, the cutting particle size of the rotor is reduced, making it easier to separate smaller particles, but it will not exceed the particle size requirements of qualified coal powder and will not affect the efficiency of the powder selection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a top view of the structure of the present invention; Figure 3 It is a flow chart of the overall steps of the present invention; Figure 4 The present invention is a flow chart of the design of the airfoil guide; Figure 5 The figure is a flow chart of the bionic blade design of the present invention.

[0018] Among them: 1. Coal drop pipe flange; 6. Coal drop pipe short section; 7. Coal drop pipe; 10. Pressure ring; 14. End cover; 18. Upper cover; 19. Powder outlet pipe; 22. Separator housing 1; 23. Connecting pipe; 25. Stationary blades; 27. Separator housing 2; 28. Forced suction type bionic blades; 31. Return hopper; 33. Separator housing 3; 39. Bracket; 47. Support frame; 48. Belt guard; 54. Separator transmission part; 55. Door cover; 93. Separator local terminal junction box; 94. Variable frequency speed regulation three-phase asynchronous motor; 95. Ceramic fiber twisted rope; 96. Powder outlet pipe flange; 97. Powder outlet pipe bottom flange. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention provides the following technical solutions: Embodiment 1 See also Figure 1-5 , a high-efficiency centrifugal coal powder selection device and method thereof, comprising a separator housing 3 33, a separator housing 2 27 is installed on the top of the separator housing 3 33; A ceramic fiber twisted rope 95 is installed at the bottom end of the separator housing 33, a return hopper 31 is arranged at the top of the separator housing 33, a forced suction type bionic blade 28 is installed inside the separator housing 27, a static blade 25 is installed inside the separator housing 27, a connecting pipe 23 is installed on the inner side of the forced suction type bionic blade 28, a separator housing 1 22 is installed at the top end of the separator housing 27, a powder outlet pipe bottom flange 97 is installed at the top end of the separator housing 1 22, a powder outlet pipe 19 is installed at the top end of the powder outlet pipe bottom flange 97, an upper cover 18 is installed at the top of the connecting pipe 23, and a The pressure ring 10 and the end cover 14 are installed on the top of the upper cover 18, the coal drop pipe 7 is installed on the top of the coal drop pipe 7, the coal drop pipe short section 6 is installed on the top of the coal drop pipe short section 6, the coal drop pipe flange 1 is installed on the top of the powder outlet pipe 19, the powder outlet pipe flange 96 is installed on the top of the powder outlet pipe 19, the separator transmission part 54 is installed on the outer wall of the upper cover 18, the belt protection cover 48 is installed on the bottom of the separator transmission part 54, the frequency conversion speed regulation three-phase asynchronous motor 94 is installed on the bottom end of the belt protection cover 48, the support frame 47 is installed on the bottom end of the separator transmission part 54, and the bracket 39 is fixedly connected to the inner side of the frequency conversion speed regulation three-phase asynchronous motor 94.

[0021] Through the above technical solution, the suction type rotor of the forced suction type bionic blade 28 is guided by the airfoil guide, and the air is forced to be sucked below the rotor, facing a larger rising wind and powder section below.

[0022] Specifically, a door cover 55 is installed at the top of the separator housing 22, and a separator on-site terminal junction box 93 is installed at the top of the separator housing 22.

[0023] Through the above technical solution, the door cover 55 is provided to facilitate maintenance and operation of the equipment. The door cover 55 is used to protect internal components and prevent dust or other impurities from entering. The separator on-site terminal junction box 93 facilitates electrical connection and maintenance.

[0024] Specifically, four powder outlet pipes 19 are provided, and the four powder outlet pipes 19 are distributed in a circular array around the top of the separator housing 22 .

[0025] Through the above technical solution, the powder outlet pipe 19 can be evenly distributed or flowed in a circular array, which helps to improve the working efficiency and stability of the equipment.

[0026] When in use, under the same primary air flow condition, when using a high-efficiency centrifugal powder selection device, the internal flow field of the coal mill is uniform, the flow rate is no more than 10m / s, and the resistance is small. The rotor of the traditional dynamic powder selection device acts as a resistance belt, and its internal resistance is large. The flow rate around is about 20m / s, and the wear is extremely large. The high-efficiency centrifugal powder selection device adopts a suction-type rotor with arc-shaped forced suction-type bionic blades 28, which is guided by an airfoil guide, and forced to suck air from the bottom of the rotor, facing a larger rising wind and powder section below; while the rotor of the traditional dynamic powder selection device rotates to form a resistance belt, and its air intake and coarse powder discharge channels overlap in the annular outer area of ​​the rotor. Therefore, the volumetric strength of the high-efficiency centrifugal powder selection device is much greater than that of the traditional powder selection device.

[0027] Embodiment 2 A method for high-efficiency centrifugal coal powder selection comprises the following steps: S1, customized design based on the coal mill conditions at the power plant, design a highly matched Laval flow field inside the centrifugal powder selection device, establish an isentropic flow model, improve the powder selection efficiency, reduce the reactive circulation of coal powder in the mill, and improve the output of the coal mill; S2, design an airfoil guide to initially separate and guide the coal powder and reduce the increase in resistance; S3, design a forced suction type bionic blade group to forcibly separate the coal powder, and avoid the unqualified coal powder being forcibly absorbed and transported; S4, using software simulation and repeated numerical calculations, ensures that the powder selection device has sufficient volumetric strength, maximum flow field matching, and can perform preliminary powder selection with low resistance and high efficiency.

[0028] Specifically, through the Laval-like flow field design, the airflow velocity distribution can be effectively adjusted to optimize the separation effect of coal powder particles. By establishing an isentropic flow model and simulating the flow state of gas under different conditions, the airflow parameters can be accurately controlled to achieve the best separation performance.

[0029] Through the above technical solutions, designs such as Laval flow fields are conducive to the formation of high-speed airflow areas, promoting the effective separation of fine particles from larger particles. The establishment of an isentropic flow model can help designers better understand the behavior of internal airflow and thus optimize the design of the device.

[0030] Specifically, computational fluid dynamics (CFD) software is used to simulate and analyze different airfoils, evaluate their flow field characteristics under actual working conditions, and conduct a comprehensive evaluation based on the two indicators of separation efficiency and drag loss. The designed airfoil guide is installed at the inlet of the powder selection device. Multiple airfoil guides should be evenly distributed on the inlet cross-section. A modular design approach is adopted to facilitate subsequent maintenance and adjustment, and high-strength and wear-resistant materials are used to manufacture the airfoil guide.

[0031] Through the above technical solution, the guide is installed at the entrance of the powder selection device to facilitate the preliminary guidance of the incoming airflow and reduce the impact of turbulence. The airfoil guide should be evenly distributed on the inlet cross section to ensure uniform airflow distribution and improve the separation effect. The airfoil guide is made of high-strength and wear-resistant materials to adapt to the high temperature and high pressure conditions in the power plant environment.

[0032] Specifically, select a bionic blade shape suitable for airflow separation, adopt a streamlined design to ensure a smooth blade surface, adjust the blade installation angle according to actual working conditions to ensure that the airflow can flow smoothly along the blade surface, and select high-strength, wear-resistant materials.

[0033] Through the above technical solution, the bionic blades choose the shape of bird wings, which can effectively reduce resistance and improve separation efficiency.

[0034] Specifically, a three-dimensional model is established, and appropriate CFD software is selected to perform detailed flow field simulation, analyze the velocity distribution of the airflow, analyze the pressure distribution of the airflow, and simulate the movement trajectory of coal powder particles in the airflow.

[0035] Through the above technical solution, the flow field simulation of the three-dimensional model can be systematically carried out to analyze the velocity distribution, pressure distribution of the airflow and the movement trajectory of the coal powder particles in the airflow.

[0036] Specifically, the angle of the blades is adjusted to ensure smooth airflow and reduce resistance, the spacing between the blades is adjusted to ensure uniform airflow distribution and improve separation efficiency, and the geometric shape of the blades is optimized to make it more suitable for airflow separation.

[0037] Through the above technical solutions, flow field analysis ensures uniform distribution of airflow, reduces turbulence, ensures smooth airflow, reduces pressure loss, and ensures initial separation effect.

[0038] When in use, the high-efficiency centrifugal powder selection device is connected to the coal mill. The coal powder in the action range is first taken into the rotor through the guide through the suction rotor of the coal mill. After entering the rotor, there is a secondary separation effect. The coarse powder particles are ejected to the outer wall of the powder selection device through the return cone and fall to the grinding disc for further grinding, while the qualified fine powder enters the coal powder pipeline under the action of airflow. When the speed is increased within an appropriate range, the cutting particle size of the rotor is reduced, making it easier to separate smaller particles, but it will not exceed the particle size requirements of qualified coal powder and will not affect the efficiency of the powder selection device.

[0039] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit thereof, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency centrifugal coal powder selection device, comprising a separator housing (33), characterized in that: The top of the separator housing 3 (33) is provided with a separator housing 2 (27); A ceramic fiber twisted rope (95) is installed at the bottom end of the separator housing three (33), a return hopper (31) is arranged at the top of the separator housing three (33), a forced suction type bionic blade (28) is installed inside the separator housing two (27), a stationary blade (25) is installed inside the separator housing two (27), a connecting pipe (23) is installed on the inner side of the forced suction type bionic blade (28), a separator housing one (22) is installed at the top end of the separator housing two (27), a powder outlet pipe bottom flange (97) is installed at the top end of the separator housing one (22), a powder outlet pipe (19) is installed at the top end of the powder outlet pipe bottom flange (97), an upper cover (18) is installed at the top end of the connecting pipe (23), and a pressure relief valve (26) is installed at the top end of the upper cover (18). A ring (10) is provided, an end cover (14) is installed at the top end of the upper cover (18), a coal drop pipe (7) is installed at the top end of the upper cover (18), a coal drop pipe short section (6) is installed at the top end of the coal drop pipe (7), a coal drop pipe flange (1) is installed at the top end of the coal drop pipe short section (6), a powder discharge pipe flange (96) is installed at the top end of the powder discharge pipe (19), a separator transmission part (54) is installed on the outer wall of the upper cover (18), a belt protection cover (48) is installed at the bottom of the separator transmission part (54), a variable frequency speed regulating three-phase asynchronous motor (94) is installed at the bottom end of the belt protection cover (48), a support frame (47) is installed at the bottom end of the separator transmission part (54), and a bracket (39) is fixedly connected to the inner side of the variable frequency speed regulating three-phase asynchronous motor (94).

2. A high-efficiency centrifugal coal powder selection device according to claim 1, characterized in that: A door cover (55) is installed at the top end of the separator housing (22), and a separator local terminal junction box (93) is installed at the top end of the separator housing (22).

3. The high-efficiency centrifugal coal powder selection device according to claim 1 is characterized in that: Four powder outlet pipes (19) are provided, and the four powder outlet pipes (19) are respectively distributed in a circular array around the top end of the separator housing 1 (22).

4. The method for high-efficiency centrifugal coal powder selection according to claim 1 is characterized in that: The following steps are involved: S1, customized design based on the coal mill conditions at the power plant, design a highly matched Laval flow field inside the centrifugal powder selection device, establish an isentropic flow model, improve the powder selection efficiency, reduce the reactive circulation of coal powder in the mill, and improve the output of the coal mill; S2, design an airfoil guide to initially separate and guide the coal powder and reduce the increase in resistance; S3, design a forced suction type bionic blade group to forcibly separate the coal powder, and avoid the unqualified coal powder being forcibly absorbed and transported; S4, using software simulation and repeated numerical calculations, ensures that the powder selection device has sufficient volumetric strength, maximum flow field matching, and can perform preliminary powder selection with low resistance and high efficiency.

5. A high-efficiency centrifugal coal powder selection method according to claim 4, characterized in that: Through the Laval-like flow field design, the airflow velocity distribution can be effectively adjusted to optimize the separation effect of coal powder particles. By establishing an isentropic flow model and simulating the flow state of gas under different conditions, the airflow parameters can be accurately controlled to achieve the best separation performance.

6. A high-efficiency centrifugal coal powder selection method according to claim 4, characterized in that: Computational fluid dynamics (CFD) software is used to simulate and analyze different airfoils, evaluate their flow field characteristics under actual working conditions, and conduct a comprehensive evaluation based on the two indicators of separation efficiency and drag loss. The designed airfoil guide is installed at the inlet of the powder selection device. Multiple airfoil guides should be evenly distributed on the inlet cross-section. A modular design approach is adopted to facilitate subsequent maintenance and adjustment, and high-strength and wear-resistant materials are used to manufacture the airfoil guide.

7. A high-efficiency centrifugal coal powder selection method according to claim 4, characterized in that: Choose a bionic blade shape suitable for airflow separation, adopt a streamlined design, ensure a smooth blade surface, adjust the blade installation angle according to actual working conditions, ensure that the airflow can flow smoothly along the blade surface, and choose high-strength, wear-resistant materials.

8. The method for high-efficiency centrifugal coal powder selection according to claim 4 is characterized in that: Establish a three-dimensional model, select appropriate CFD software to perform detailed flow field simulation, analyze the velocity distribution of the airflow, analyze the pressure distribution of the airflow, and simulate the movement trajectory of coal powder particles in the airflow.

9. A high-efficiency centrifugal coal powder selection method according to claim 4, characterized in that: Adjust the angle of the blades to ensure that the airflow can flow smoothly and reduce resistance, adjust the spacing between the blades to ensure uniform airflow distribution and improve separation efficiency, and optimize the geometric shape of the blades to make it more suitable for airflow separation.

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