A particle size and particle size distribution detection device

Abstract

The present invention relates to the field of coal combustion detection in thermal power plants, and particularly refers to a device for detecting particle size and particle size distribution. The device for detecting particle size and particle size distribution includes: a detection channel, a particle size and particle size distribution detector, and a classification device; the classification device divides the coal flow in the detection channel into multiple grades according to particle size, and a particle size and distribution detector is provided for each grade of coal flow. The coal flow into the furnace is divided into different grades by the classification device, and then each grade of coal flow is detected by the particle size and distribution detector. According to the detection results, the particle size and particle size distribution of the coal into the furnace can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of coal combustion detection in thermal power plants, and particularly to a device for detecting particle size and particle size distribution. Background Art

[0002] Large-scale circulating fluidized bed boilers (CFB) in coal-fired power plants have superior performance such as high efficiency, low pollution, adaptability to various fuels, good load regulation performance, and strong comprehensive availability of ash and slag. However, CFB boilers also impose strict requirements on the particle size and particle size distribution of the fuel entering the furnace. The particle size, particle size distribution, and particle size grading of the coal entering the furnace have a great impact on the ignition start-up, operation control, and combustion efficiency of the circulating fluidized bed boiler.

[0003] The basic requirement during the operation of a circulating fluidized bed boiler is that the distribution of the dilute phase zone and the dense phase zone during bed material fluidization is normal, and the bed temperature is maintained stable. Therefore, it is necessary to ensure the particle size of the coal entering the furnace and have an appropriate screening ratio. For example, when a large amount of large coal blocks enter the fluidized bed for combustion during operation, they will deposit in the bed body to form a dead zone, destroying the normal fluidization state, making the temperature field in the furnace uneven, and causing coking due to too low or too high bed temperature, resulting in forced shutdown of the furnace. If the particle composition of the coal is too fine, it will cause elutriation of fine powder, and even the separator cannot capture it, and it will enter the tail flue without complete combustion, resulting in an increase in tail fly ash and an increase in the carbon content of fly ash (up to more than 50% in severe cases), reducing the thermal efficiency of the boiler. Therefore, it is particularly important to timely sample and detect the particle size and particle size distribution of the coal entering the furnace.

[0004] At present, most circulating fluidized bed power plants detect the particle size and particle size distribution of the coal entering the furnace by mechanical sampling or manual sampling and then using laboratory testing methods; depending on the coal type, the general testing time is 6 - 8 hours, and the testing is carried out once per shift. Therefore, the current method has the following disadvantages:

[0005] 1) It cannot perform real-time detection and timely analysis of the particle size effect at the outlet of the crusher to discover problems and take adjustment measures;

[0006] 2) Due to the influence of human factors and objective conditions, there are deviations in the detection results.

[0007] For power plants without an intermediate grading coal bunker, the coal after being crushed by the secondary coal crusher directly enters the boiler for combustion through a belt. Since the manual sampling and testing time is long, information feedback cannot be obtained in a timely manner, and the coal has already been sent into the furnace for combustion, which is not conducive to operation adjustment and is not conducive to preventing and controlling the occurrence of boiler operation production accidents caused by excessive particle size in advance.

[0008] For the detection of the particle size and particle size distribution of the coal fed into the furnace in a thermal power plant, the commonly used method in current laboratory tests is as follows: According to GB / T 477-2008 Coal Screening Test Method, by using the large screening and small screening methods, the particle size grades of the coal fed into the furnace are analyzed and inspected by mass. With the development of new technologies, there are several new particle size instruments and methods so far: dynamic light scattering method, nanoparticle tracking analysis technology, resonant mass measurement technology, laser diffraction technology, spatial filtering velocimeter, and automatic imaging technology.

[0009] However, all existing detections of the coal fed into the furnace are in the laboratory detection stage and cannot achieve on-line detection of the coal fed into the furnace. Summary of the Invention

[0010] The present invention provides a device for detecting particle size and particle size distribution, which solves the problem that the coal fed into the furnace cannot be detected on-line in the prior art.

[0011] The technical solution of the present invention is realized as follows:

[0012] A device for detecting particle size and particle size distribution includes: a detection channel, a particle size and particle size distribution detector, and a classification device;

[0013] The classification device divides the coal flow in the detection channel into multiple grades according to particle size, and a particle size and distribution detector is provided corresponding to each grade of coal flow.

[0014] Preferably, the particle size and distribution detector includes a laser phase array emission device and a laser phase array receiving device arranged oppositely.

[0015] Preferably, the detection channel is a barrel-shaped structure surrounded by multiple side plates, which includes a front side plate, a rear side plate, a left side plate, and a right side plate;

[0016] The laser phase array emission device is arranged on the front side plate, and the laser phase array receiving device is arranged on the rear side plate;

[0017] The classification device is an acoustic purge classification device, which is arranged on the left side plate, and a coal particle channel is provided corresponding to each acoustic purge classification device on the right side plate.

[0018] Preferably, multiple platforms are arranged on the front side plate, and a laser phase array emission device is arranged on each platform of the front side plate;

[0019] Multiple platforms are arranged on the rear side plate, and a laser phase array receiving device is arranged on each platform of the rear side plate;

[0020] Multiple platforms are arranged on the left side plate, and an acoustic purge classification device is arranged on each platform of the left side plate.

[0021] Preferably, the laser phased array emission device includes a laser generator, an emission housing, an emission protection screen, and an emission screen cleaning brush;

[0022] The laser generator is fixed inside the emission housing, and the emission protection screen is fixed on one side of the emission housing;

[0023] The side of the emission housing having the emission protection screen is connected to the detection channel, and the emission end of the laser generator is arranged facing the emission protection screen.

[0024] Preferably, the laser phased array receiving device includes a laser receiver, a receiving housing, a receiving protection screen, and a receiving screen cleaning brush;

[0025] The laser receiver is fixed inside the receiving housing, and the receiving protection screen is fixed on one side of the receiving housing;

[0026] The side of the receiving housing having the receiving protection screen is connected to the detection channel, and the receiving end of the laser receiver is arranged facing the receiving protection screen.

[0027] Preferably, the acoustic purging and classification device includes an acoustic generator and a gas source;

[0028] The acoustic generator is communicated with the gas source;

[0029] Inside the detection channel, a plurality of acoustic generators are arranged side by side from bottom to top.

[0030] Preferably, for adjacent acoustic generators, the acoustic power of the acoustic generator with a lower setting position is greater than that of the acoustic generator with a higher setting position.

[0031] Preferably, the inlet end of the detection channel is communicated with the upper end of the coal dropping hopper through a sampling shunt device, and the outlet end of the detection channel is communicated with the lower end of the coal dropping hopper through a lower interface;

[0032] Both the sampling shunt device and the lower interface are channels for coal flow with an inclined setting, and the detection channel is a channel for coal flow with a vertical setting.

[0033] Preferably, it further includes a large particle coal channel;

[0034] The lower end of the sampling shunt device is provided with a detection channel blanking port, and the side wall of the sampling shunt device is provided with a large particle blanking port;

[0035] The detection channel blanking port is communicated with the sampling shunt device of the detection channel;

[0036] The large particle blanking port is communicated with the sampling shunt device of the large particle coal channel;

[0037] A large particle filter screen is arranged at the inlet end of the detection channel blanking port.

[0038] The technical solution of the present invention divides the coal flow into the furnace into different grades through a grading device, and then detects each grade of coal flow through a particle size and distribution detector. According to the detection results, the particle size and particle size distribution of the coal into the furnace can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 Schematic diagram of the coal conveying system provided for the specific embodiment of the present invention;

[0041] Figure 2 Schematic diagram of the particle size and particle size distribution detection device provided for the specific embodiment of the present invention;

[0042] Figure 3 is Figure 2 "A-A direction" cross-sectional view;

[0043] Figure 4 Schematic diagram of another angle of the particle size and particle size distribution detection device provided for the specific embodiment of the present invention

[0044] Figure 5 is Figure 4 "B-B direction" cross-sectional view;

[0045] Figure 6 Schematic diagram of the grading device provided for the specific embodiment of the present invention;

[0046] Figure 7 Right view of the grading device provided for the specific embodiment of the present invention.

[0047] 1: Coal crusher; 2: Vibrating screen; 3: Coal dropping hopper; 4: Particle size and particle size distribution detection device; 5: Conveyor belt;

[0048] 41: Detection channel; 42: Particle size and distribution detector; 43: Grading device; 44: Sampling and shunting device; 45: Lower interface; 46: Large particle coal channel;

[0049] 411: Front side plate; 412: Rear side plate; 413: Left side plate; 414: Right side plate;

[0050] 421: Laser phased array emission device; 422: Laser phased array receiving device;

[0051] 4211: Laser generator; 4212: Emission housing; 4213: Emission protection screen;

[0052] 4221: Laser receiver; 4222: Reception housing; 4223: Reception protection screen;

[0053] 431: Acoustic wave generator; 432: Gas source; 433: Outer protective housing; 434: Outlet protection housing;

[0054] 441: Coal diversion port; 442: Detection channel blanking port; 443: Large particle blanking port; 444: Large particle filter screen. Detailed implementation mode

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0056] As Figures 1 to 7 shown, in this embodiment, a particle size and particle size distribution detection device includes: a detection channel 41, a particle size and distribution detector 42, and a classification device 43;

[0057] The classification device divides the coal flow in the detection channel into multiple grades according to the particle size, and a particle size and distribution detector is provided for each grade of coal flow;

[0058] The classification device 43 divides the coal flow in the detection channel 41 into multiple grades according to the particle size, and a particle size and distribution detector 42 is provided for each grade of coal flow.

[0059] In this embodiment, the classification device divides the coal flow into the furnace into different grades, and then detects each grade of coal flow through the particle size and distribution detector. According to the detection results, the particle size and particle size distribution of the coal in the furnace can be obtained. Therefore, the on-line detection of the particle size and particle size distribution of the furnace coal is realized.

[0060] The operator can accordingly timely perform targeted adjustment on the boiler to ensure that the boiler operates under the best working conditions and improve the boiler combustion efficiency.

[0061] The present invention can timely avoid the combustion operation accidents of the circulating fluidized bed boiler caused by the large particle size of the coal in the furnace, reduce the boiler operation accidents, and at the same time can directly reduce the power consumption of the plant electricity, bringing direct economic benefits to the power plant.

[0062] To further explain the above particle size and particle size distribution detection device, this embodiment also provides a coal conveying system, and the particle size and particle size distribution detection device is arranged on the coal conveying system. Specifically, it is described as follows:

[0063] A coal conveying system includes: a coal crusher 1, a vibrating screen 2, a coal dropping hopper 3, a particle size and particle size distribution detection device 4, and a conveyor belt 5.

[0064] The vibrating screen 2 is arranged at the lower end of the coal crusher 1. The outlet end of the coal crusher 1 is communicated with the inlet end of the coal dropping hopper 3, and the outlet end of the coal dropping hopper 3 is located above the conveyor belt 5.

[0065] The inlet end of the detection channel 41 is communicated with the upper end of the coal dropping hopper 3, and the outlet end of the detection channel 41 is communicated with the lower end of the coal dropping hopper 3.

[0066] Particle size and particle size distribution detection device 4

[0067] Referring to Figures 2 to 5 , the inlet end of the detection channel 41 is communicated with the upper end of the coal dropping hopper 3 through a sampling shunt device 44, and the outlet end of the detection channel 41 is communicated with the lower end of the coal dropping hopper 3 through a lower interface 45.

[0068] Both the sampling shunt device 44 and the lower interface 45 are inclined channels for coal flow, and the detection channel 41 is a vertically arranged channel for coal flow.

[0069] The particle size and particle size distribution detection device 4 further includes a large particle coal channel 46.

[0070] Specifically, a coal diversion port 441 is arranged at the upper end of the sampling shunt device 44, a detection channel feeding port 442 is arranged at the lower end of the sampling shunt device 44, and a large particle feeding port 443 is arranged on the side wall of the sampling shunt device 44.

[0071] The coal diversion port 441 is communicated with the upper end of the coal dropping hopper 3, the detection channel feeding port 442 is communicated with the upper interface of the detection channel 41, and the large particle feeding port 443 is communicated with the upper interface of the large particle coal channel 46. The lower interface of the large particle coal channel 46 is communicated with the lower end of the coal dropping hopper 3. Among them, a large particle filter screen 444 is arranged at the inlet end of the detection channel feeding port.

[0072] For the coal conveyed in the coal dropping hopper 3, part of the coal will enter the sampling shunt device 44 through the coal diversion port 441. Under the screening action of the large particle filter screen 444, part of the coal passes through the large particle filter screen 444 and enters the detection channel 41 through the detection channel feeding port, and the remaining part enters the large particle coal channel 46 through the large particle feeding port under the blocking action of the large particle filter screen 444. The coal passing through the large particle coal channel 46 and the detection channel 41 finally returns to the hopper 3.

[0073] The particle size and distribution detector 42 includes a laser phased array transmitting device 421 and a laser phased array receiving device 422 which are oppositely arranged.

[0074] The laser phased array transmitting device 421 includes a laser generator 4211, a transmitting housing 4212, a transmitting protection screen 4213 and a transmitting screen cleaning brush.

[0075] The laser generator 4211 is fixed inside the transmitting housing 4212, and the transmitting protection screen 4213 is fixed on one side of the transmitting housing 4212.

[0076] The side of the transmitting housing 4212 having the transmitting protection screen 4213 is connected to the detection channel 41. The emitting end of the laser generator 4211 is arranged facing the transmitting protection screen 4213, and the laser emitted by the laser generator 4211 can pass through the transmitting protection screen 4213 and enter the detection channel 41.

[0077] The transmitting screen cleaning brush is arranged on the transmitting protection screen 4213. The transmitting screen cleaning brush can clean the transmitting protection screen 4213 and can remove the coal ash on the transmitting protection screen 4213.

[0078] The laser phased array receiving device 422 includes a laser receiver 4221, a receiving housing 4222, a receiving protection screen 4223 and a receiving screen cleaning brush.

[0079] The laser receiver 4221 is fixed inside the receiving housing 4222, and the receiving protection screen 4223 is fixed on one side of the receiving housing 4222.

[0080] The side of the receiving housing 4222 having the receiving protection screen 4223 is connected to the detection channel 41. The receiving end of the laser receiver 4221 is arranged facing the receiving protection screen 4223, and the laser receiver 4221 can receive the laser emitted by the laser transmitter 4211.

[0081] Further, both the transmitting housing 4212 and the receiving housing 4222 are connected to the detection channel 41 through a channel or an opening, and a transmitting protection screen 4213 and a receiving protection screen 4223 are respectively arranged on the corresponding channel or opening, so that the laser emitted by the laser generator 4211 can be received by the oppositely arranged laser receiver 4221.

[0082] The receiving screen cleaning brush is arranged on the receiving protection screen 4223. The receiving screen cleaning brush can clean the receiving protection screen 4223 and can remove the coal ash on the receiving protection screen 4223.

[0083] It should be emphasized that the laser phased array transmitting device 421 and the laser phased array receiving device 422 are arranged in pairs. According to the number of grades divided by the particle size of the coal flow bundle, the corresponding number of laser phased array transmitting devices 421 and laser phased array receiving devices 422 will be set accordingly.

[0084] The detection channel 41 is a barrel-shaped structure surrounded by multiple side plates, which includes a front side plate 411, a rear side plate 412, a left side plate 413, and a right side plate 414.

[0085] Multiple platforms for placing the laser phased array transmitting devices 421 are provided on the front side plate 411, and one laser phased array transmitting device 421 is provided on each platform of the front side plate 411.

[0086] Multiple platforms for placing the laser phased array receiving devices 422 are provided on the rear side plate 412, and one laser phased array receiving device 422 is provided on each platform of the rear side plate 412.

[0087] Classification device 43

[0088] Refer to Figure 6 、 Figure 7 The classification device 43 includes a sound wave generator 431 and a gas source 432, and the sound wave generator 431 is communicated with the gas source 432.

[0089] In the detection channel 41, multiple sound wave generators 431 are arranged side by side from bottom to top, and coal discharge ports are provided at the positions corresponding to the open ends of each sound wave generator 431 on the side wall of the detection channel 41.

[0090] In this embodiment, the coal to be fed into the furnace flows in the detection channel 41. When the coal to be fed into the furnace passes through the sound wave generator, the sound wave generator 431 will blow some coal particles in the coal to be fed into the furnace to the coal discharge port. By arranging multiple sound wave generators 431 in the detection channel 41 and controlling the sound wave power of the sound wave generators 431, the coal to be fed into the furnace can be divided into multiple different coal particle grades. That is, during the transmission process of the coal to be fed into the furnace, the classification of the coal to be fed into the furnace can be realized.

[0091] For adjacent sound wave generators, the sound wave power of the sound wave generator with a lower setting position is greater than that of the sound wave generator with a higher setting position.

[0092] Specifically, the sound wave power of the multiple sound wave generators arranged from top to bottom gradually increases.

[0093] The greater the power of the sound wave generator, the larger the coal particles blown out by it. For adjacent sound wave generators, the power of the sound wave generator with a lower setting position is greater than that of the sound wave generator with a higher setting position, which can realize the separation of the coal to be fed into the furnace into a gradually increasing particle size range from top to bottom. The gradual increase here can be a linear increase or a non-linear increase.

[0094] Specifically, if it is necessary to divide the coal entering the furnace in the detection channel 41 into seven grades, since the particle size of the coal entering the furnace in the detection channel gradually increases, only six acoustic purging and grading devices need to be set in the detection channel. The acoustic wave generator 431 of each grading device 43 corresponds to a unique frequency band, and the generated acoustic wave airflow can separate coal particles within different particle size ranges (see Table 1).

[0095] The grading device 43 further includes an outer protective shell 433 and an outlet protective shell 434. The acoustic wave generator 431 is arranged inside the outer protective shell 433, and the outlet protective shell 434 is arranged at the outlet end of the outer protective shell 433.

[0096] And at least the outlet protective shell 434 of the acoustic purging and grading device extends into the detection channel 41. Through this setting, it can be ensured that the acoustic waves emitted by the acoustic purging and grading device can enter the detection channel 41.

[0097] The length of the outlet protective shell 433 gradually decreases from top to bottom. Usually, the detection channel 41 is arranged vertically. The coal entering the furnace flows in the detection channel 41 from top to bottom. By setting the outlet protective shell 433 into the above structure, it can prevent the coal entering the furnace from entering the acoustic purging and grading device.

[0098] The acoustic wave generator 431 includes a straight pipe section and a bell mouth section. Among them, the inlet end of the straight pipe section is connected to the gas source 432, and the outlet section of the straight pipe section is connected to the inlet end of the bell mouth section. Specifically, a branch pipe is connected to the inlet end of the straight pipe section of the acoustic wave generator 431 of each acoustic purging and grading device. After each branch pipe and a main pipe are connected, they are connected to the gas source 432 through the main pipe.

[0099] The outlet protective shell 434 has a plurality of uniformly arranged grid holes, and the cross-section of the grid holes is square, rectangular or diamond-shaped. The purpose of setting the grid holes is to prevent the coal entering the furnace from entering the acoustic purging and grading device. The specific shape of the grid holes can be set according to actual needs.

[0100] The detection channel 41 is a barrel-shaped structure surrounded by a plurality of side plates, which includes a front side plate 411, a rear side plate 412, a left side plate 413 and a right side plate 414.

[0101] Specifically, a plurality of platforms for placing the grading device 43 are arranged on the left side plate 413 of the detection channel. Each platform of the left side plate 413 is provided with a grading device 43. The opening end of the acoustic wave generator 431 of the grading device 43 is arranged towards the detection channel 41 and can generate acoustic waves into the detection channel 41. Correspondingly, a coal outlet is arranged on the right side plate 414 at the position corresponding to the opening end of each grading device acoustic wave generator.

[0102] In order to collect the coal particles separated by the classifying device 43, the online acoustic wave classifying device also includes a large-particle coal channel. The detection channel is connected to the large-particle coal channel through the coal outlet. The coal separated by the classifying device 43 will eventually enter the large-particle coal channel.

[0103] In order to further explain the above-mentioned coal conveying system, in this embodiment, a method for detecting the particle size and particle size distribution of coal entering the furnace is also provided, which comprises the following steps:

[0104] This embodiment processes the incoming coal of the coal-fired system of a circulating fluidized bed boiler thermal power plant, and the details are as follows:

[0105] The incoming coal of the thermal power plant is processed by the coal crusher 1 and the vibrating screen 2 and then falls into the coal hopper 3. In the coal hopper 3, part of the incoming coal is collected by the sampling and diversion device 44 and enters the particle size and particle size distribution detection device 4. The particle size and particle size distribution detection device 4 performs online dynamic detection of the particle size and particle size distribution of the incoming coal (the detection method mainly uses the existing laser diffraction method to determine the particle size and particle size distribution of solid particles in the sample to be tested, such as the application numbers CN201410195405.5 and CN201811391569.X disclose similar methods), and transmits the detection data to the analyzer control station through the data and control cables for processing; the analyzer control station obtains the particle size and particle size distribution result data of the incoming coal after calculation and processing, and provides the data to the operator or the automatic control system.

[0106] The incoming coal after detection returns to the lower passage of the coal hopper 3 through the lower interface 45, and finally falls onto the incoming coal conveying belt 5, and then is transported to the boiler room.

[0107] The incoming coal is sampled online after passing through the coal diversion port 441 of the sampling and diversion device 44. After the sampling and diversion, the incoming coal passes through the large particle filter 444, and the coal particles with a particle size of more than 6 mm are separated. The coal particles with a particle size of more than 6 mm directly enter the large particle coal channel through the large particle discharge port 443. Coal particles with a particle size of ≤6 mm pass through the detection channel discharge port 442 and fall into the detection channel 41. When passing through the large particle discharge port 443, the coal particles with a particle size of more than 6 mm are detected online by the large particle metering device, and the data is transmitted to the analyzer control station through a cable.

[0108] The detection channel is divided into seven layers along the vertical elevation. On the right side plate 414 of the corresponding coal particle channel, a classifier 43 is installed in each layer. The sound wave generator 431 of each classifier 43 corresponds to a unique frequency band, and the corresponding sound wave airflow can purge and separate coal particles within different particle sizes and particle diameters (see Table 1) from the coal flow stream entering the furnace for sampling, and purge and separate them into the large-particle coal channel 46.

[0109] Table 1: Corresponding Relationship between Coal Particle Size and Frequency Power

[0110]

[0111] The coal particles separated by purging converge and fall into the coal hopper 3, and finally fall onto the coal conveyor belt 5 through the coal hopper 3.

[0112] Classification devices 43 are provided in the front several layers of areas. For the large coal particles of 4.5 - 6 mm in the bottommost layer, no classification device is provided. They directly pass through the lower end of the detection channel and return through the lower interface 45 to enter the lower channel of the outlet of the coal hopper 3 at the rear end of the vibrating screen, and finally fall onto the coal conveyor belt 5 of the transfer station.

[0113] When the coal particle stream for in-furnace sampling passes through the detection channel 41, the classification device 43 can perform on-line classification processing on the coal particle stream for in-furnace sampling; it can be classified into in-furnace coal sampling streams with different particle size levels in different detection channel layer areas, providing a basic guarantee for improving the subsequent detection accuracy.

[0114] On the corresponding seven-layer platforms on the front side plate 411 of the detection channel 41, one laser phased array emission device 421 is fixed on each layer; on the corresponding seven-layer platforms on the rear side plate 412 of the detection channel 41, one laser phased array receiving device 422 is fixed on each layer; when the coal for furnace enters through the detection channel 41, the laser beam emitted by each laser phased array emission device 421 passes through the coal particles falling instantaneously in the channel and is received by the corresponding laser phased array receiving device 422; the laser phased array receiving device 422 transmits the received optical signal to the analyzer control station through data and control cables.

[0115] The single laser beam emitted by each laser phased array emission device 421 becomes a parallel light with a diameter of 25 - 30 mm after being focused, low-pass filtered and collimated. The multiple parallel light beams emitted by the laser generator 4211 in each laser phased array emission device 421 are superimposed to form a parallel phased array light beam with a cross-section of: width 200 mm - 400 mm, height 100 mm - 200 mm.

[0116] After the parallel phased array light beam irradiates and passes through the coal particle beam in the detection channel 41, it reaches the laser receiver 4221 in the corresponding laser phased array receiving device 422. Due to the coal particle beams with different particle sizes in the furnace blocking or refracting the passing laser beams, the energy of the laser phased array light beam after passing through the gaps between the coal particles is attenuated, so that the intensity of the laser beam energy signal collected by the laser receiver 4221 in the laser phased array receiving device is weakened and distributed within a specific intensity value range.

[0117] When the parallel phased array beam emitted by the laser phased array emission device 421 passes through the sampled coal flow beam that has been processed by layering and grading, since the sampled coal flow beam of each layer has been processed into different particle size levels, when the phased array beam passes through the gaps between coal particles of different particle size levels, the intensity attenuation of the laser beam is different. Therefore, the intensity of the laser beam energy signal collected by the laser receiver 4221 in the laser phased array receiving device 422 is also different, and the intensity distribution of the laser beam energy signal collected corresponding to different particle sizes and particle size levels is within different intensity value ranges. By establishing a calculation model for the intensity attenuation of the laser beam corresponding to different particle sizes and performing simulation calculations through computer software in the analyzer control station, the proportion of the layered particle sizes of the coal entering the furnace can be accurately calculated, and finally the particle size distribution result can be obtained, realizing the practical application of on-line detection of the particle size of the coal entering the furnace.

[0118] In summary, in the process of on-line detection of the particle size and particle size distribution of the coal entering the circulating fluidized bed boiler in this embodiment, the grading device can perform on-line grading processing on the particle flow beam of the sampled coal entering the furnace; in different detection coal channel layer areas, the sampled coal flow beam of the coal entering the furnace can be processed into different particle size levels, providing a basic guarantee for improving the subsequent detection accuracy.

[0119] This embodiment uses a laser phased array emission device to emit a parallel phased array beam; the cross-sectional size of the emitted parallel phased array beam is wide. Similarly, the laser phased array receiving device has a wide signal receiving range, and a new method can be established for the corresponding calculation model of the sampled coal flow beam with different particle size distributions and the intensity attenuation of the laser phased array beam, which can improve the accuracy of on-line detection of particle size and particle size distribution.

[0120] This embodiment can track in real time the particle size and particle size distribution of the sampled coal entering the furnace after the secondary coal crusher and the vibrating screen. The on-line detection speed is fast, and full coal flow sampling detection can be realized, reducing the influence of human factors; it enables the operating personnel to monitor the working conditions of the coal crusher and the vibrating screen at any time and adjust the particle size of the coal entering the furnace in a timely manner;

[0121] This embodiment can also provide in real time the data of the particle size and particle size distribution of the sampled coal entering the furnace. The operating personnel can accordingly adjust the boiler in a targeted manner in a timely manner to ensure that the boiler operates under the best conditions and improve the combustion efficiency of the boiler.

[0122] The present invention can timely avoid the combustion operation accidents of the circulating fluidized bed boiler caused by the large particle size of the coal entering the furnace, reduce the boiler operation accidents, and at the same time directly reduce the power consumption of the plant, bringing direct economic benefits to the power plant.

[0123] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

[0124] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A particle size and particle size distribution detection device, characterized in that, Including: A detection channel, a particle size and particle size distribution detector, and a classification device; the classification device divides the coal flow in the detection channel into multiple grades according to the particle size, and a particle size and distribution detector is provided for each grade of coal flow. The particle size and distribution detector includes a laser phased array emission device and a laser phased array receiving device arranged opposite to each other. The detection channel is a barrel-shaped structure surrounded by multiple side plates, including a front side plate, a rear side plate, a left side plate, and a right side plate; the laser phased array emission device is arranged on the front side plate, and the laser phased array receiving device is arranged on the rear side plate; the classification device is an acoustic purge classification device, the acoustic purge classification device is arranged on the left side plate, and a coal particle channel is provided on the right side plate corresponding to each acoustic purge classification device. The laser phased array emission device includes a laser generator, an emission housing, an emission protection screen, and an emission screen cleaning brush; the laser generator is fixed in the emission housing, and the emission protection screen is fixed on one side of the emission housing; the side of the emission housing with the emission protection screen is connected to the detection channel, and the emission end of the laser generator is arranged facing the emission protection screen. The acoustic purge classification device includes an acoustic generator and a gas source; the acoustic generator is communicated with the gas source; in the detection channel, multiple acoustic generators are arranged side by side from bottom to top. For adjacent acoustic generators, the acoustic power of the acoustic generator with a lower setting position is greater than that of the acoustic generator with a higher setting position. The acoustic generator of each acoustic purge classification device corresponds to a frequency band.

2. The particle size and particle size distribution detection device according to claim 1, characterized in that Multiple platforms are arranged on the front side plate, and a laser phased array emission device is arranged on each platform of the front side plate; multiple platforms are arranged on the rear side plate, and a laser phased array receiving device is arranged on each platform of the rear side plate; multiple platforms are arranged on the left side plate, and an acoustic purge classification device is arranged on each platform of the left side plate.

3. The particle size and particle size distribution detection device according to claim 1, characterized in that, The laser phased array receiving device includes a laser receiver, a receiving housing, a receiving protection screen, and a receiving screen cleaning brush; the laser receiver is fixed in the receiving housing, and the receiving protection screen is fixed on one side of the receiving housing; the side of the receiving housing with the receiving protection screen is connected to the detection channel, and the receiving end of the laser receiver is arranged facing the receiving protection screen.

4. The particle size and particle size distribution detection device according to claim 1, wherein The inlet end of the detection channel is communicated with the upper end of the coal dropping hopper through a sampling shunt device, and the outlet end of the detection channel is communicated with the lower end of the coal dropping hopper through a lower interface; both the sampling shunt device and the lower interface are inclined channels for the coal flow to pass through, and the detection channel is a vertical channel for the coal flow to pass through.

5. The particle size and particle size distribution detection device according to claim 4, characterized in that, It further includes a large particle coal channel; a detection channel discharge port is arranged at the lower end of the sampling shunt device, and a large particle discharge port is arranged on the side wall of the sampling shunt device; the detection channel discharge port is communicated with the sampling shunt device of the detection channel; the large particle discharge port is communicated with the sampling shunt device of the large particle coal channel; a large particle filter screen is arranged at the inlet end of the detection channel discharge port.

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