A coal transport system

Abstract

The present invention relates to the field of coal combustion detection in thermal power plants, and in particular to a coal conveying system. The coal conveying system includes a coal crusher, a vibrating screen, a coal hopper, a particle size and particle size distribution detection device and a conveying belt; the vibrating screen is arranged at the lower end of the coal crusher, the outlet end of the coal crusher is connected to the inlet end of the coal hopper, and the outlet end of the coal hopper is located at the upper part of the conveying belt; the particle size and particle size distribution detection device includes a detection channel, a particle size and distribution detector and a grading device; the grading 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 arranged corresponding to each grade of coal flow; the inlet end of the detection channel is connected to the upper end of the coal hopper, and the outlet end of the detection channel is connected to the lower end of the coal hopper. The coal conveying system can realize online detection of the particle size and particle size distribution of the coal entering the furnace. Based on this, the boiler can be adjusted in a targeted manner in a timely manner to improve the combustion efficiency of the boiler.

Description

Technical Field

[0001] The invention relates to the field of coal combustion detection in thermal power plants, in particular to a coal conveying system. Background Art

[0002] Large circulating fluidized bed boilers (CFB) in coal-fired power plants have the advantages of high efficiency, low pollution, adaptability to a variety of fuels, good load regulation performance, and strong comprehensive availability of ash and slag. However, CFB boilers also have strict requirements on the particle size and particle grading of the fuel entering the furnace. The particle size, particle size distribution and particle 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 for the operation of a circulating fluidized bed boiler is that the dilute phase and dense phase are normally distributed when the bed material is boiling, and the bed temperature is kept stable. Therefore, the particle size of the coal entering the furnace must be guaranteed, and there must be an appropriate screening ratio. If a large number of large coal blocks enter the fluidized bed for combustion during operation, they will be deposited in the bed to form a dead zone, destroying the normal fluidization state, making the temperature field in the furnace uneven, and will be forced to shut down due to coking caused by the bed temperature being too low or too high. If the particle components of the coal are too fine, it will cause the fine powder to be separated, and even the separator cannot capture it. It will enter the tail flue before it is completely burned, resulting in an increase in the tail fly ash and an increase in the carbon content of the fly ash (up to 50% or more in severe cases), which reduces the thermal efficiency of the boiler. Therefore, it is particularly important to sample and test the particle size and particle size distribution of the coal entering the furnace in a timely manner.

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

[0005] 1) It is impossible to detect and analyze the crusher outlet particle size effect in real time to find problems and take adjustment measures;

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

[0007] For power plants without intermediate grading coal bunkers, the coal crushed by the secondary coal crusher goes directly into the boiler for combustion via a belt. Due to the long time of manual sampling and testing, timely detection and information feedback cannot be obtained, and the coal has already been sent to the furnace for combustion, which is not conducive to operation regulation and is not conducive to early prevention and control of boiler operation production accidents caused by excessive particle size.

[0008] The common laboratory test method for testing the particle size and particle size distribution of coal entering the furnace in thermal power plants is: according to the GB / T 477-2008 coal screening test method, the particle size and particle size distribution of coal entering the furnace are analyzed and tested according to the quality according to the large screening and small screening methods. With the development of new technologies, the new particle size instruments and methods so far include the following: dynamic light scattering method, nanoparticle tracking analysis technology, resonance mass measurement technology, laser diffraction technology, spatial filter velocimeter, and automatic imaging technology.

[0009] However, the existing detection of coal entering the furnace is all in the laboratory detection stage, and online detection of coal entering the furnace cannot be achieved. Summary of the invention

[0010] The present invention provides a coal conveying system, which solves the problem in the prior art that coal entering a furnace cannot be detected online.

[0011] The technical solution of the present invention is achieved in this way:

[0012] A coal conveying system, comprising: a coal crusher, a vibrating screen, a coal drop bucket, a particle size and particle size distribution detection device and a conveying belt;

[0013] The vibrating screen is arranged at the lower end of the coal crusher, the outlet end of the coal crusher is connected with the inlet end of the coal hopper, and the outlet end of the coal hopper is located on the upper part of the conveyor belt;

[0014] The particle size and particle size distribution detection device comprises a detection channel, a particle size and distribution detector and a classification device;

[0015] The grading device divides the coal flow in the detection channel into multiple grades according to the particle size, and sets a particle size and distribution detector corresponding to each grade of coal flow;

[0016] The inlet end of the detection channel is communicated with the upper end of the coal dropping hopper, and the outlet end of the detection channel is communicated with the lower end of the coal dropping hopper.

[0017] Preferably, the inlet end of the detection channel is connected to the upper end of the coal hopper through a sampling and diversion device, and the outlet end of the detection channel is connected to the lower end of the coal hopper through a lower interface;

[0018] The sampling and diversion device and the lower interface are both inclined channels for coal circulation, and the detection channel is a vertically arranged channel for coal circulation.

[0019] Preferably, the particle size and distribution detector comprises a laser phase array transmitting device and a laser phase array receiving device which are arranged opposite to each other.

[0020] Preferably, it also includes a large particle coal channel;

[0021] The lower end of the sampling and diversion device is provided with a detection channel discharge port, and the side wall of the sampling and diversion device is provided with a large particle discharge port;

[0022] The testing channel discharge port is connected to the sampling and diversion device of the testing channel;

[0023] The large particle discharge port is connected to the sampling and diversion device of the large particle coal channel;

[0024] A large particle filter screen is provided at the inlet end of the discharge port of the detection channel.

[0025] Preferably, the classification device comprises a sound wave generator and a gas source;

[0026] The sound wave generator is connected to the gas source;

[0027] In the detection channel, a plurality of sound wave generators are arranged side by side from bottom to top.

[0028] Preferably, a coal outlet is provided on the detection channel at a position corresponding to the opening end of each sound wave generator.

[0029] Preferably, among the adjacently arranged sound wave generators, the sound wave power of the sound wave generator at a lower setting position is greater than the power of the sound wave generator at a higher setting position.

[0030] Preferably, the sound wave powers of the multiple sound wave generators arranged from top to bottom gradually increase.

[0031] Preferably, the grading device further comprises an outer protective shell and an outlet protective shell;

[0032] The sound wave generator is arranged in the outer protective shell, and the outlet protective shell is arranged at the outlet end of the outer protective shell;

[0033] At least the outlet protective shell of the sonic wave purge classification device extends into the detection channel.

[0034] Preferably, it also includes an analyzer control station, and the particle size and distribution detector is electrically connected to the analyzer control station.

[0035] In the technical solution of the present invention, the grading device divides the coal flow into different grades, and then uses the particle size and distribution detector to detect the coal flow of each grade. The particle size and particle size distribution of the coal entering the furnace can be obtained according to the test results. The operator can make targeted adjustments to the boiler in a timely manner to ensure that the boiler operates under the best working conditions and improve the boiler combustion efficiency.

[0036] The present invention can timely avoid combustion operation accidents of circulating fluidized bed boilers caused by large particle size of coal entering the furnace, reduce boiler operation accidents, and directly reduce power consumption of the plant, thus bringing direct economic benefits to the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A schematic diagram of the structure of a coal transportation system provided in a specific embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the structure of a particle size and particle size distribution detection device provided in a specific embodiment of the present invention;

[0040] Figure 3 yes Figure 2 "AA" section view;

[0041] Figure 4 This is a schematic diagram of the structure of the particle size and particle size distribution detection device provided by the specific embodiment of the present invention from another angle

[0042] Figure 5 yes Figure 4 "BB direction" section view;

[0043] Figure 6 It is a structural schematic diagram of a grading device provided in a specific embodiment of the present invention;

[0044] Figure 7 It is a right side view of the grading device provided in a specific embodiment of the present invention.

[0045] 1: Coal crusher; 2: Vibrating screen; 3: Coal hopper; 4: Particle size and particle size distribution detection device; 5: Conveyor belt;

[0046] 41: detection channel; 42: particle size and distribution detector; 43: classification device; 44: sampling and diversion device; 45: lower interface; 46: large particle coal channel;

[0047] 411: front side panel; 412: rear side panel; 413: left side panel; 414: right side panel;

[0048] 421: laser phase array transmitting device; 422: laser phase array receiving device;

[0049] 4211: laser generator; 4212: launch shell; 4213: launch protection screen;

[0050] 4221: laser receiver; 4222: receiving housing; 4223: receiving protection screen;

[0051] 431: sound wave generator; 432: gas source; 433: outer protective shell; 434: outlet protective shell;

[0052] 441: coal diversion port; 442: detection channel discharge port; 443: large particle discharge port; 444: large particle filter screen. DETAILED DESCRIPTION

[0053] 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.

[0054] like Figures 1 to 7 As shown, in this embodiment, a coal conveying system is provided, which includes: a coal crusher 1, a vibrating screen 2, a coal hopper 3, a particle size and particle size distribution detection device 4 and a conveyor belt 5.

[0055] The vibrating screen 2 is arranged at the lower end of the coal crusher 1 , the outlet end of the coal crusher 1 is connected with the inlet end of the coal hopper 3 , and the outlet end of the coal hopper 3 is located on the upper part of the conveyor belt 5 .

[0056] The particle size and particle size distribution detection device 4 includes a detection channel 41 , a particle size and distribution detector 42 and a classification device 43 .

[0057] 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 set corresponding to each grade of the coal flow.

[0058] 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 .

[0059] In this embodiment, the grading device divides the coal flow into different grades, and then uses the particle size and distribution detector to detect the coal flow of each grade. The particle size and particle size distribution of the coal entering the furnace can be obtained based on the test results. The operator can make targeted adjustments to the boiler in a timely manner to ensure that the boiler operates under the best working conditions and improve the boiler combustion efficiency.

[0060] The present invention can timely avoid combustion operation accidents of circulating fluidized bed boilers caused by large particle size of coal entering the furnace, reduce boiler operation accidents, and directly reduce power consumption of the plant, thus bringing direct economic benefits to the power plant.

[0061] Particle size and particle size distribution detection device 4

[0062] Reference Figures 2 to 5 The inlet end of the detection channel 41 is connected to the upper end of the coal hopper 3 through the sampling and diversion device 44, and the outlet end of the detection channel 41 is connected to the lower end of the coal hopper 3 through the lower interface 45.

[0063] The sampling and diverting device 44 and the lower interface 45 are both inclined channels for coal circulation, and the detection channel 41 is a vertically arranged channel for coal circulation.

[0064] The particle size and particle size distribution detection device 4 also includes a large-particle coal channel 46 .

[0065] Specifically, a coal guide port 441 is disposed at the upper end of the sampling and diverting device 44 , a detection channel discharge port 442 is disposed at the lower end of the sampling and diverting device 44 , and a large particle discharge port 443 is disposed on the side wall of the sampling and diverting device 44 .

[0066] The coal guide port 441 is connected to the upper end of the coal hopper 3, the detection channel discharge port 442 is connected to the upper interface of the detection channel 41, and the large particle discharge port 443 is connected to the upper interface of the large particle coal channel 46. The lower interface of the large particle coal channel 46 is connected to the lower end of the coal hopper 3. Among them, a large particle filter screen 444 is provided at the inlet end of the detection channel discharge port.

[0067] Part of the coal transported in the coal hopper 3 will enter the sampling and diversion device 44 through the coal diversion port 441. Under the screening effect of the large particle filter screen 444, part of the coal entering the sampling and diversion device 44 passes through the large particle filter screen 444 and enters the detection channel 41 through the detection channel discharge port. The remaining part enters the large particle coal channel 46 through the large particle discharge port under the blocking effect 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.

[0068] The particle size and distribution detector 42 includes a laser phase array transmitting device 421 and a laser phase array receiving device 422 which are arranged opposite to each other.

[0069] The laser phased array emitting device 421 includes a laser generator 4211, an emitting shell 4212, an emitting protection screen 4213 and an emitting screen cleaning brush.

[0070] The laser generator 4211 is fixed in the launch shell 4212 , and the launch protection screen 4213 is fixed on one side of the launch shell 4212 .

[0071] One side of the emission shell 4212 having an emission protection screen 4213 is connected to the detection channel 41 , the emission end of the laser generator 4211 is arranged toward the emission protection screen 4213 , and the laser emitted by the laser generator 4211 can pass through the emission protection screen 4213 into the detection channel 41 .

[0072] The emission screen cleaning brush is arranged on the emission protection screen 4213. The emission screen cleaning brush can clean the emission protection screen 4213 and remove the coal dust on the emission protection screen 4213.

[0073] The laser phased array receiving device 422 includes a laser receiver 4221, a receiving shell 4222, a receiving protection screen 4223 and a receiving screen cleaning brush.

[0074] The laser receiver 4221 is fixed in the receiving shell 4222 , and the receiving protection screen 4223 is fixed on one side of the receiving shell 4222 .

[0075] The receiving shell 4222 has a side with a receiving protection screen 4223 connected to the detection channel 41 , the receiving end of the laser receiver 4221 is arranged toward the receiving protection screen 4223 , and the laser receiver 4221 can receive the laser emitted by the laser transmitter 4211 .

[0076] Furthermore, the transmitting shell 4212 and the receiving shell 4222 are both 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 channels or openings, so that the laser emitted by the laser generator 4211 can be received by the laser receiver 4221 arranged oppositely.

[0077] 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 soot on the receiving protection screen 4223.

[0078] It should be emphasized that the laser phased array emitting device 421 and the laser phased array receiving device 422 are arranged in pairs. According to the number of grades of the coal flow particle size, a corresponding number of laser phased array emitting devices 421 and laser phased array receiving devices 422 will be arranged accordingly.

[0079] The detection channel 41 is a barrel-shaped structure surrounded by a plurality of side panels, including a front side panel 411 , a rear side panel 412 , a left side panel 413 and a right side panel 414 .

[0080] A plurality of platforms for placing laser phased array emitting devices 421 are arranged on the front side plate 411 , and a laser phased array emitting device 421 is arranged on each platform of the front side plate 411 .

[0081] A plurality of platforms for placing laser phased array receiving devices 422 are arranged on the rear side plate 412 , and a laser phased array receiving device 422 is arranged on each platform of the rear side plate 412 .

[0082] Classification device 43

[0083] Reference Figure 6 , Figure 7The classification device 43 includes a sound wave generator 431 and a gas source 432 , and the sound wave generator 431 is in communication with the gas source 432 .

[0084] In the detection channel 41 , a plurality of sound wave generators 431 are arranged side by side from bottom to top, and a coal outlet is arranged on the side wall of the detection channel 41 at a position corresponding to the opening end of each sound wave generator 431 .

[0085] In this embodiment, the incoming coal flows in the detection channel 41. When the incoming coal passes through the acoustic wave generator, the acoustic wave generator 431 will sweep some coal particles in the incoming coal to the coal outlet. By arranging multiple acoustic wave generators 431 in the detection channel 41 and controlling the acoustic wave power of the acoustic wave generator 431, the incoming coal can be classified into multiple different coal particle grades. That is, the classification of the incoming coal can be achieved during the transmission process of the incoming coal.

[0086] For the adjacently arranged sound wave generators, the sound wave power of the sound wave generator at a lower setting position is greater than the sound wave generator at a higher setting position.

[0087] Specifically, the sound wave powers of the multiple sound wave generators arranged from top to bottom gradually increase.

[0088] The greater the power of the acoustic wave generator, the larger the coal particles it blows out. For adjacent acoustic wave generators, the power of the acoustic wave generator at a lower setting is greater than that of the acoustic wave generator at a higher setting, so that the coal entering the furnace can be separated into particle sizes that gradually increase from top to bottom. The gradual increase here can be linear or nonlinear.

[0089] Specifically, if it is necessary to classify the incoming coal in the detection channel 41 into seven grades, since the particle size of the incoming coal in the detection channel gradually increases, it is sufficient to set six sonic wave purge classification devices in the detection channel. The sonic wave generator 431 of each classification device 43 corresponds to a unique frequency band, and the corresponding sonic wave airflow can classify coal particles within different particle sizes and particle size ranges (see Table 1).

[0090] The classification device 43 further includes an outer protective shell 433 and an outlet protective shell 434. The sound wave generator 431 is arranged in the outer protective shell 433, and the outlet protective shell 434 is arranged at the outlet end of the outer protective shell 433.

[0091] At least the outlet protective shell 434 of the sonic wave purge classification device extends into the detection channel 41 . This arrangement ensures that the sonic waves emitted by the sonic wave purge classification device can enter the detection channel 41 .

[0092] The length of the outlet protection shell 433 gradually decreases from top to bottom. Generally, the detection channel 41 is arranged in the vertical direction. The incoming coal flows from top to bottom in the detection channel 41. By setting the outlet protection shell 433 into the above structure, the incoming coal can be prevented from entering the sonic purging and classification device.

[0093] The acoustic wave generator 431 includes a straight pipe section and a bell-mouth section, wherein the inlet end of the straight pipe section is connected to the gas source 432, and the outlet end of the straight pipe section is connected to the inlet end of the bell-mouth section. Specifically, the inlet end of the straight pipe section of the acoustic wave generator 431 of each acoustic wave purge classification device is connected to a branch pipe. Each branch pipe is connected to a main pipe and then connected to the gas source 432 through the main pipe.

[0094] The outlet protection shell 434 has a plurality of evenly arranged grille holes, and the cross-section of the grille holes is square, rectangular or diamond-shaped. The purpose of providing the grille holes is to prevent the coal entering the furnace from entering the sonic purge classification device. The specific shape of the grille holes can be set according to actual needs.

[0095] The detection channel 41 is a barrel-shaped structure surrounded by a plurality of side panels, including a front side panel 411 , a rear side panel 412 , a left side panel 413 and a right side panel 414 .

[0096] Specifically, a plurality of platforms for placing the grading devices 43 are arranged on the left side plate 413 of the detection channel, and a grading device 43 is arranged on each platform of the left side plate 413. The opening end of the sound wave generator 431 of the grading device 43 is arranged toward the detection channel 41, and can generate sound waves into the detection channel 41. Correspondingly, a coal outlet is arranged on the right side plate 414 at a position corresponding to the opening end of the sound wave generator of each grading device.

[0097] 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.

[0098] 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:

[0099] 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:

[0100] 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.

[0101] 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 is then transported to the boiler room.

[0102] 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.

[0103] 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.

[0104] Table 1: Correspondence between coal particle size and frequency power

[0105]

[0106]

[0107] The purged and separated coal particles converge and fall into the coal drop hopper 3 , and finally fall onto the coal conveyor belt 5 through the coal drop hopper 3 .

[0108] The first few layers are all equipped with grading devices 43, but the bottom layer of large-particle coal of 4.5--6 mm is not equipped with a grading device. It directly passes through the lower end of the detection channel and returns through the lower interface 45 to enter the lower outlet channel of the coal hopper 3 at the rear end of the vibrating screen, and finally falls onto the coal conveyor belt 5 of the transfer station.

[0109] When the coal particle flow stream of the sampling entering the furnace passes through the detection channel 41, the grading device 43 can perform online grading processing on the coal particle flow stream of the sampling entering the furnace; the coal sampling flow stream of the sampling entering the furnace can be graded into different particle size levels in different detection channel layer areas, which provides a basic guarantee for improving the accuracy of subsequent detection.

[0110] On each of the seven platforms corresponding to the front side plate 411 of the detection channel 41, a laser phased array transmitting device 421 is fixed; on each of the seven platforms corresponding to the rear side plate 412 of the detection channel 41, a laser phased array receiving device 422 is fixed; when the incoming coal passes through the detection channel 41, the laser beam emitted by each laser phased array transmitting device 421 passes through the coal particles falling instantly in the channel and is then 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 the data and control cables.

[0111] The single laser beam emitted by each laser phased array emitting device 421 is focused, low-pass filtered and collimated to become a parallel light with a diameter of 25-30 mm. The multiple parallel lights emitted by the laser generator 4211 in each laser phased array emitting device 421 are superimposed to form a parallel phased array light beam with a cross section of 200 mm-400 mm in width and 100 mm-200 mm in height.

[0112] 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. Since the coal particle beams of different particle sizes entering the furnace block or refract the passing laser beam, the energy of the laser phased array light beam that finally passes through the gap between the coal particles is attenuated, and 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.

[0113] When the parallel phased array light beam emitted by the laser phased array transmitting device 421 passes through the sampled coal flow that has been processed by stratification and grading, since the sampled coal flow of each layer has been processed into different particle size levels, the intensity attenuation of the laser beam is different when the phased array light beam passes through the gaps between coal particles of different particle size levels. 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 of the laser beam energy signal collected corresponding to different particle size levels is distributed within different intensity value ranges. By establishing a laser beam intensity attenuation calculation model corresponding to different particle sizes, and simulating and calculating by computer software in the analyzer control station, the layered particle size ratio of the coal entering the furnace can be accurately deduced, and finally the particle size distribution result is obtained, realizing the practical application of online detection of the particle size of the inlet coal.

[0114] To sum up, in the process of online 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 online classification processing on the sampling coal particle flow stream entering the furnace; the sampling coal flow streams entering the furnace can be graded into different particle size levels in different detection coal channel layer areas, which provides a basic guarantee for improving the accuracy of subsequent detection.

[0115] This embodiment uses a laser phased array transmitting device to emit parallel phased array light beams; the cross-sectional size of the emitted parallel phased array light beams is wide, and similarly, the range of receiving signals by the laser phased array receiving device is wide, and a new method for the corresponding calculation model of the sampling coal flow beams with different particle size distributions and the attenuation of the laser phased array beam intensity can be established, which can improve the accuracy of online detection of particle size and particle size distribution.

[0116] This implementation method can timely track the particle size and particle size distribution of the coal sampled after the secondary coal crusher and the vibrating screen entering the furnace online. The online detection speed is fast, and the whole coal flow sampling detection can be realized to reduce the influence of human factors; it can enable 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 time;

[0117] This implementation can also provide online and timely data on the particle size and particle size distribution of the coal sampled into the furnace, so that the operating personnel can make targeted adjustments to the boiler in a timely manner to ensure that the boiler operates under optimal conditions and improve the boiler combustion efficiency.

[0118] The present invention can timely avoid combustion operation accidents of circulating fluidized bed boilers caused by large particle size of coal entering the furnace, reduce boiler operation accidents, and directly reduce power consumption of the plant, thus bringing direct economic benefits to the power plant.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A coal transportation system, characterized in that: include: Coal crusher, vibrating screen, coal hopper, particle size and particle size distribution detection device and conveyor belt; The vibrating screen is arranged at the lower end of the coal crusher, the outlet end of the coal crusher is connected with the inlet end of the coal hopper, and the outlet end of the coal hopper is located on the upper part of the conveyor belt; The particle size and particle size distribution detection device comprises a detection channel, a particle size and distribution detector and a classification device; The grading device divides the coal flow in the detection channel into multiple grades according to the particle size, and sets a particle size and distribution detector corresponding to each grade of coal flow; The inlet end of the detection channel is connected to the upper end of the coal hopper, and the outlet end of the detection channel is connected to the lower end of the coal hopper; The inlet end of the detection channel is connected to the upper end of the coal hopper through the sampling and diversion device, and the outlet end of the detection channel is connected to the lower end of the coal hopper through the lower interface; The sampling and diversion device and the lower interface are both inclined channels for coal circulation, and the detection channel is a vertically arranged channel for coal circulation; The particle size and distribution detector comprises a laser phase array transmitting device and a laser phase array receiving device which are arranged opposite to each other; Also included is a large particle coal channel; The lower end of the sampling and diversion device is provided with a detection channel discharge port, and the side wall of the sampling and diversion device is provided with a large particle discharge port; The testing channel discharge port is connected to the sampling and diversion device of the testing channel; The large particle discharge port is connected to the sampling and diversion device of the large particle coal channel; A large particle filter screen is provided at the inlet end of the testing channel feed port; The classification device includes a sound wave generator and a gas source; The sound wave generator is connected to the gas source; In the detection channel, a plurality of sound wave generators are arranged side by side from bottom to top; The detection channel is provided with a coal outlet at a position corresponding to the opening end of each sound wave generator.

2. The coal transportation system according to claim 1, characterized in that: For the adjacently arranged sound wave generators, the sound wave power of the sound wave generator at a lower setting position is greater than the sound wave generator at a higher setting position.

3. The coal transportation system according to claim 2, characterized in that: The sound wave powers of the multiple sound wave generators arranged from top to bottom gradually increase.

4. The coal transportation system according to claim 1, characterized in that: The grading device also includes an outer protective shell and an outlet protective shell; The sound wave generator is arranged in the outer protective shell, and the outlet protective shell is arranged at the outlet end of the outer protective shell; At least the outlet protective shell of the sonic wave purge classification device extends into the detection channel.

5. The coal transportation system according to claim 1, characterized in that: It also includes an analyzer control station, and the particle size and distribution detector is electrically connected to the analyzer control station.

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