Multi-channel coal quality characteristic online detection system and detection method for pulverized coal pipe

Abstract

The invention discloses a multi-channel coal quality characteristic online detection system and method for a pulverized coal pipe, the device comprises a control center, a sample feeding device and a detection device, the detection device comprises a laser, a spectrometer, a lens assembly, a light path switching mechanism and a measurement chamber, and the light path switching mechanism is arranged between the laser and the measurement chamber; the lens assembly comprises total reflection lenses, focusing lens sets and light receiving lens sets, each light path switching mechanism is provided with one total reflection lens, one focusing lens set is arranged on the side face of each measuring chamber and located between the total reflection lenses and the measuring chambers, and the light receiving lens sets are further arranged on the other side face of each measuring chamber. And the spectrograph is connected with the light receiving lens group through an optical fiber. After the detection is completed, the control center analyzes to obtain a test result. According to the invention, pulverized coal in a plurality of pulverized coal pipes can be detected in a short time, the purpose of mastering the coal quality change of multiple paths of pulverized coal in real time is achieved, the detection efficiency is effectively improved, and the detection cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of physical detection, and in particular relates to a multi-channel coal quality characteristic online detection system and a detection method for a pulverized coal pipe. Background Art

[0002] Pulverized coal testing is a key component in ensuring efficient combustion and safe production. Coal quality analysis of incoming coal is a complex, systematic task, encompassing elemental analysis for carbon, hydrogen, oxygen, nitrogen, and sulfur. Industrial analyses include moisture, volatile matter, ash, fixed carbon, and calorific value. Real-time collection of coal quality data is a key component in enabling digital management of coal-fired power plants and a crucial support for further enhancing their low-carbon, clean, flexible, and safe operation.

[0003] Existing coal-fired power plants have a low level of automation in coal quality analysis for incoming coal. Manual sampling is typically performed and sent to the laboratory for offline testing. This method is time-sensitive and makes it difficult to assess changes in coal pulverized properties in real time. While more advanced testing methods exist, such as using a sampling system to extract pulverized coal and passing it through a cyclone separator for solid-gas separation, the solid phase is analyzed online using thermogravimetric methods. Alternatively, pulverized coal is pressed into pellets and analyzed using laser-induced breakdown spectroscopy (LIBS). However, these two methods are complex and difficult to adapt to industrial sites. Furthermore, cyclones screen the pulverized coal particles based on mass, making them difficult to meet representative testing requirements.

[0004] In addition, the quality of pulverized coal produced by different pulverizers in coal-fired power plants varies greatly. Even if it is tested by automated analysis equipment, different analysis equipment is difficult to share, the problem of delayed test results remains unsolved, and the overall testing cost is also high.

[0005] Based on this, the present invention proposes a novel multi-channel coal quality characteristics online detection system and detection method to solve the above problems. Summary of the Invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a multi-channel coal quality characteristics online detection system and detection method for coal powder pipes, which can detect the coal powder in multiple coal powder pipes in a relatively short time, thereby achieving the purpose of real-time grasp of the coal quality changes of multiple coal powders, effectively improving the detection efficiency and reducing the detection cost.

[0007] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect of the present invention, a multi-channel coal quality characteristics online detection system for a pulverized coal pipe is provided, comprising:

[0009] Control Center;

[0010] Sample delivery device, connected to the control center;

[0011] A detection device comprising a laser, a spectrometer, a lens assembly, an optical path switching mechanism, and a measurement chamber, wherein the plurality of measurement chambers are connected to the sample delivery device, the plurality of optical path switching mechanisms are disposed between the laser and the plurality of measurement chambers, and the optical path switching mechanisms correspond one to one to the measurement chambers;

[0012] Along the optical path of the laser emitted by the laser, a plurality of optical path switching mechanisms are arranged from front to back;

[0013] The lens assembly includes a total reflection lens, a focusing lens group and a light-collecting lens group. A total reflection lens is provided in each optical path switching mechanism. A focusing lens group is provided on the side of each measuring chamber. The focusing lens group is located between the total reflection lens and the measuring chamber. A light-collecting lens group is further provided on the other side of each measuring chamber. The spectrometer is connected to the light-collecting lens group via an optical fiber.

[0014] The laser, the spectrometer and the optical path switching mechanism are all connected to a control center.

[0015] Preferably, the multiple total reflection lenses are arranged parallel to each other.

[0016] More preferably, the incident angle of the laser on the multiple total reflection lenses is 45°.

[0017] Preferably, for the same measuring chamber, the light collecting lens group is located on one side of the focusing lens group.

[0018] More preferably, the light collecting lens group is arranged adjacent to the focusing lens group.

[0019] Preferably, the sample delivery device includes a compressed air source, a pressure regulating valve group and a pulverized coal pipe, the compressed air source is connected to the pressure regulating valve group, the pressure regulating valve group is connected to the control center, the number of the pulverized coal pipes is the same as the number of the measuring chambers, and a delivery pipe and a sample return pipe are arranged between each of the pulverized coal pipes and the corresponding measuring chamber, wherein a sampling injector is arranged on the delivery pipe, and the air inlet of the sampling injector is connected to the pressure regulating valve group.

[0020] Preferably, a first valve is provided between the pulverized coal pipe and the sampling injector, a second valve is provided between the sampling injector and the measuring chamber, and a third valve is provided on the sample return pipe.

[0021] Preferably, a sample return injector is provided at the connection between the measuring chamber and the sample return tube, and the sample return injector is connected to the pressure regulating valve group.

[0022] Preferably, the first valve, the second valve and the third valve are all automatic valves, and are all connected to the control center.

[0023] In a second aspect of the present invention, a multi-channel coal quality characteristics online detection method for a pulverized coal pipe is provided as follows:

[0024] S1. The sample delivery device delivers pulverized coal to all measuring chambers in the detection device, and a pulverized coal flow is formed in each measuring chamber;

[0025] S2. The optical path switching mechanism corresponding to the measurement room to be tested controls the total reflection lens to enter the laser optical path, and the remaining total reflection lenses in front of the total reflection lens leave the laser optical path;

[0026] S3. The laser emits a laser, which is reflected and focused by a focusing lens group onto the coal powder flow in the center of the corresponding measuring chamber. Plasma is generated at the focused position. The plasma light signal is focused by a light-receiving lens group on the other side of the measuring chamber onto the end face of an optical fiber. The optical fiber transmits the light signal to the spectrometer for photoelectric conversion. The data converted by the spectrometer is transmitted to the control center for data analysis to obtain the coal quality characteristic data of the coal powder in the corresponding measuring chamber.

[0027] S4. After completing step S3, if it is necessary to continue detecting the coal powder in other measuring chambers, repeat steps S2-S3; if it is no longer necessary to detect the coal powder, all the total reflection lenses leave the laser light path and the detection device stops detecting.

[0028] Beneficial effects:

[0029] The sample delivery device of the present invention can realize multi-channel flow sampling and return sampling. The sampling and return sample channels are in a normal flow state, which can effectively reduce the blockage of the sampling pipeline. At the same time, the detection device automatically detects the coal powder in different channels. Because the present invention detects coal powder based on the laser-induced breakdown spectroscopy method, the detection speed is fast. Through the cooperation of multiple optical path switching mechanisms in the detection device, the present invention can detect coal powder in multiple coal powder pipes in a relatively short time, achieving the purpose of real-time monitoring of coal quality changes in multiple coal powder channels, effectively improving detection efficiency and reducing detection costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is a schematic diagram of a detection device of the present invention;

[0031] Figure 2 Shown are schematic diagrams of two different detection states in the detection device;

[0032] Figure 3 Shown is a schematic diagram of the sample delivery device of the present invention.

[0033] Reference numerals:

[0034] 1- Control Center;

[0035] 2-Detection device, 21-Laser, 22-Spectrometer, 23-Measuring chamber, 24-Optical path switching mechanism, 25-Total reflection lens, 26-Focusing lens group, 27-Light collecting lens group, 28-Optical fiber, 29-Return sample ejector;

[0036] 3-sample delivery device, 31-compressed air source, 32-pressure regulating valve group, 33-coal powder pipe, 34-delivery pipe, 35-sample return pipe, 36-sampling injector, 37-first valve, 38-second valve, 39-third valve. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without inventive work.

[0038] like Figure 1-3 As shown, the present invention proposes a multi-channel online coal quality characteristic detection system for pulverized coal pipes, comprising a control center 1, a sample delivery device 3, and a detection device 2. The control center 1 is connected to the sample delivery device 3 and the detection device 2, respectively. After completing the test, the control center 1 analyzes and obtains the test results. The sample delivery device 3 is connected to the detection device 2 to achieve automatic sample delivery and detection. The technical solution of the present invention is described in detail below using a specific structure.

[0039] The structure of the detection device 2 is as follows Figure 1 As shown, the detection device 2 includes a laser 21, a spectrometer 22, a lens assembly, an optical path switching mechanism 24 and a measuring chamber 23. The multiple measuring chambers 23 are connected to the sample delivery device 3. The multiple optical path switching mechanisms 24 are arranged between the laser 21 and the multiple measuring chambers 23, and the optical path switching mechanisms 24 correspond to the measuring chambers 23 one by one.

[0040] Along the optical path of the laser emitted by the laser 21, multiple optical path switching mechanisms 24 are arranged from front to back. The lens assembly includes a total reflection lens 25, a focusing lens group 26, and a light-collecting lens group 27. Each optical path switching mechanism 24 is provided with a total reflection lens 25. A focusing lens group 26 is provided on the side of each measuring chamber 23. The focusing lens group 26 is located between the total reflection lens 25 and the measuring chamber 23. A light-collecting lens group 27 is also provided on the other side of each measuring chamber 23. The spectrometer 22 is connected to the light-collecting lens group 27 via an optical fiber 28. The laser 21, spectrometer 22, and optical path switching mechanism 24 are all connected to the control center 1. To avoid external influences, the measuring chamber is non-transparent except for the position of the light-collecting lens group 27. For example, the measuring chamber is made of metal material, and a position for installing the light-collecting lens group 27 is provided, while the rest of the measuring chamber blocks external light.

[0041] like Figure 1-2 As shown, for the same measuring chamber 23, the light collecting lens group 27 is located on one side of the focusing lens group 26. Preferably, the light collecting lens group 27 is adjacent to the focusing lens group 26. The light collecting lens group 27 does not overlap with the focusing lens group 26 or is not located on the other side opposite to the focusing lens group 26 to avoid direct exposure to the laser.

[0042] The control center 1 of the present invention is an existing conventional computer or other equipment, which can issue instructions and process experimental data, and will not be described in detail below.

[0043] The function of the optical path switching mechanism 24 is to change the position of the total reflection lens 25. The position of the total reflection lens 25 on the optical path switching mechanism 24 when the total reflection lens 25 enters the optical path from which the laser is emitted is referred to as position 1, and the position of the total reflection lens 25 on the optical path switching mechanism 24 when the total reflection lens 25 leaves the optical path is referred to as position 0. It is easy to understand that, for multiple optical path switching mechanisms 24 in which the total reflection lens 25 is in position 1, only the total reflection lens 25 in the optical path switching mechanism 24 located at the frontmost position can reflect the laser. Therefore, the optical path switching mechanism 24 corresponding to the measuring chamber 23 where coal powder needs to be detected controls the total reflection lens 25 to enter the laser optical path, and at this time, the total reflection lens 25 is located at the frontmost position in the laser optical path. The positions of the remaining total reflection lenses 25 located behind the total reflection lens 25 are not restricted.

[0044] Based on the above multi-channel coal quality characteristics online detection system, the present invention also proposes a multi-channel coal quality characteristics online detection method as follows:

[0045] S1, the sample delivery device 3 delivers pulverized coal to all the measuring chambers 23 in the detection device 2, and a pulverized coal flow is formed in each measuring chamber 23;

[0046] S2, the optical path switching mechanism 24 corresponding to the measuring room 23 that needs to be tested controls the total reflection lens 25 to enter the laser optical path, and the other total reflection lenses 25 in front of the total reflection lens 25 leave the laser optical path;

[0047] S3: The laser 21 emits a laser, which is reflected by the focusing lens group 26 and focused on the coal powder flow in the center of the corresponding measuring chamber 23. Plasma is generated at the focused position. The plasma light signal is focused on the end face of the optical fiber 28 by the light-receiving lens group 27 on the other side of the measuring chamber 23. The optical fiber 28 transmits the light signal to the spectrometer 22 for photoelectric conversion. The data converted by the spectrometer 22 is transmitted to the control center 1 for data analysis to obtain the coal quality characteristic data of the coal powder in the corresponding measuring chamber 23.

[0048] S4. After completing step S3, if it is necessary to continue detecting the coal powder in other measuring chambers 23, repeat steps S2-S3; if it is no longer necessary to detect the coal powder, all the total reflection lenses 25 leave the laser light path and the detection device 2 stops detecting.

[0049] by Figure 2 Taking the three optical path switching mechanisms 24 as an example, the corresponding measuring chambers 23 are channels A, B, and C, that is, measuring chambers A, B, and C. When the total reflection lenses 25 of the three optical path switching mechanisms 24 are all in position 1, only the total reflection lens 25 located in the front and closest to the laser 21 reflects the laser. At this time, it is in the measurement state of channel A. After reflection, the laser is focused on the coal powder flow beam in the center of the corresponding measuring chamber A by the focusing lens group 26, and plasma is generated at the focused position. The plasma light signal is focused on the end face of the optical fiber 28 by the light-receiving lens group 27 on the other side of the measuring chamber 23. The optical fiber 28 transmits the light signal to the spectrometer 22 for photoelectric conversion. The data converted by the spectrometer 22 is transmitted to the control center 1 for data analysis, and finally the coal quality characteristic data of the coal powder in the corresponding measuring chamber A is obtained. When the coal quality characteristics of the pulverized coal in channel B need to be measured, the optical path switching mechanism 24 corresponding to channel A switches the total reflection mirror 25 to position 0, and the total reflection mirror 25 leaves the laser light path. At this time, the total reflection mirror 25 corresponding to channel B is in the laser light path, and the pulverized coal in channel B is detected. Similarly, when the coal quality characteristics of the pulverized coal in channel C need to be measured, the total reflection mirrors 25 corresponding to channels A and B are both out of the laser light path.

[0050] The present invention can detect the pulverized coal in a specific measuring chamber 23, or it can perform cyclic detection, sequentially measuring the coal quality characteristics of the pulverized coal in multiple measuring chambers 23. The cyclic detection method can be various, such as controlling the optical path switching mechanism 24 from front to back along the laser light path, causing multiple total reflection lenses 25 to regularly enter or leave the optical path. After completing the pulverized coal detection in the last measuring chamber 23, the system returns to the front measuring chamber 23 and detects it again in the order from front to back. Alternatively, after completing the pulverized coal detection in the last measuring chamber 23, the system directly detects multiple measuring chambers 23 in the order from back to front.

[0051] by Figure 1 Taking the three optical path switching mechanisms 24 as an example, one cycle can be to detect the coal powder in the measuring chambers A, B, and C in sequence according to ABC. After completing the coal powder detection in the measuring chamber C, the total reflection lenses 25 corresponding to the measuring chambers A and B enter the optical path again, and then detect in the order from front to back. Or one cycle can be to detect the coal powder in the measuring chambers A, B, and C in sequence according to ABCBA. After completing the coal powder detection in the measuring chamber C in the order of ABC, the total reflection lens 25 corresponding to the measuring chamber B enters the optical path, and detects the coal powder in the measuring chamber B again. Then the total reflection lens 25 corresponding to the measuring chamber A enters the optical path, and detects the coal powder in the measuring chamber A again.

[0052] In the present invention, the incident angle of the laser beam entering the total reflection mirror 25 can vary. Since the laser beam needs to be focused within the corresponding measurement chamber 23 after reflection, the arrangement of the total reflection mirror 25 is related to the location of the measurement chamber 23. Preferably, multiple total reflection mirrors 25 are arranged parallel to each other, and the incident angle of the laser beam on each of the total reflection mirrors 25 can be acute or right angle. More preferably, the incident angle of the laser beam on each of the total reflection mirrors 25 is 45°.

[0053] In the present invention, the optical path switching mechanism 24 changes the position of the total reflection lens 25. The present invention does not impose any specific restrictions on the structure of the optical path switching mechanism 24. For example, the optical path switching mechanism 24 can be a screw device, and the total reflection lens 25 is arranged on the screw device, and the screw device controls the linear movement of the total reflection lens 25.

[0054] The structure of the sample delivery device 3 is as follows: Figure 3As shown, the sample delivery device 3 includes a compressed air source 31, a pressure regulating valve group 32, and a pulverized coal pipe 33. The compressed air source 31 is connected to the pressure regulating valve group 32, which is connected to the control center 1. The number of pulverized coal pipes 33 is the same as the number of measuring chambers 23. A delivery pipe 34 and a sample return pipe 35 are provided between each pulverized coal pipe 33 and the corresponding measuring chamber 23. The pulverized coal particles output from the pulverized coal pipe 33 enter the corresponding measuring chamber 23 along the delivery pipe 34, and the pulverized coal particles in the measuring chamber 23 return to the pulverized coal pipe 33 along the sample return pipe 35. A sampling injector 36 is provided on the delivery pipe 34, and the air inlet of the sampling injector 36 is connected to the pressure regulating valve group 32. The compressed air source 31 is generally independently controlled, which is easy to understand. The compressed air source 31 can also be controlled by the control center 1 and can be set according to actual conditions.

[0055] The compressed air source 31 inputs compressed air into the sampling injector 36 through the pressure regulating valve group 32, so that a negative pressure is formed in the sampling injector 36, and the pulverized coal particles in the pulverized coal pipe 33 are extracted and input into the measuring chamber 23 along the conveying pipe 34. Since the pulverized coal pipe 33, the conveying pipe 34, the measuring chamber 23 and the return sample pipe 35 form a connected pipeline, the high-pressure air drives the pulverized coal particles to move along this path. After the detection is completed, the pulverized coal particles return to the pulverized coal pipe 33.

[0056] Figure 3 A', B', C' refer to three pulverized coal pipes 33, and the pulverized coal pipes A', B', C' correspond to the measuring chambers A, B, C one by one.

[0057] It is easy to understand that in order to prevent sampling interference, along the flow direction of the pulverized coal pipe 33 , the connection between the return sample pipe 35 and the pulverized coal pipe 33 is located downstream of the connection between the sampling pipe and the pulverized coal pipe 33 .

[0058] Furthermore, a first valve 37 is provided between the pulverized coal pipe 33 and the sampling injector 36, a second valve 38 is provided between the sampling injector 36 and the measuring chamber 23, and a third valve 39 is provided on the sample return pipe 35. In the present invention, the pulverized coal pipe 33 maintains a state of conveying pulverized coal. When testing is required, the first valve 37, the second valve 38, and the third valve 39 are opened to allow the pulverized coal to enter the testing device 2. It will be readily understood that closing the first valve 37 and the third valve 39 can isolate the pulverized coal pipe 33 from the measuring chamber 23.

[0059] It is easy to understand that the opening and closing status of the valve on each pulverized coal pipe 33 is related to the detection requirements. The pulverized coal pipe 33 maintains the flow of pulverized coal. When the pulverized coal in one of the pulverized coal pipes 33 needs to be detected, the first valve 37, the second valve 38 and the third valve 39 corresponding to the pulverized coal pipe 33 are opened to allow the pulverized coal in the pulverized coal pipe 33 to be input into the corresponding measuring chamber 23.

[0060] Combine Figure 3It can be seen that based on the settings of the valves on the delivery pipe 34 and the sample return pipe 35, the delivery mechanism has the following functions:

[0061] If one of the pulverized coal pipes 33 is in a state of suspending the conveyance of pulverized coal, the first valve 37 and the third valve 39 are closed to cut off the connection between the pulverized coal pipe 33 and the detection device 2. It should be noted that it is normal for the pulverized coal pipe 33 to convey pulverized coal to the detection device 2 and take samples. Generally, the conveyance of pulverized coal will not be suspended due to channel switching within the detection device 2. This working state allows the pulverized coal in the pulverized coal pipe 33 to flow for a long time, which helps prevent blockage. However, in certain special circumstances, when the pulverized coal pipe 33 suspends the conveyance of pulverized coal, such as when the conveyance of pulverized coal needs to be suspended due to combustion control, the corresponding pulverized coal pipe 33 also needs to suspend sampling. There are multiple pulverized coal pipes 33, and the first valve 37 and the third valve 39 corresponding to one or several of the pulverized coal pipes 33 can be closed, and the remaining pulverized coal pipes 33 are normally connected to the detection device 2.

[0062] When the delivery pipe 34 between the sampling injector 36 and the detection device 2 is blocked or the sample return pipe 35 is blocked, the first valve 37 is closed, the second valve 38 and the third valve 39 are opened, and high-pressure air is input into the sampling injector 36 to clear the delivery pipe 34.

[0063] When the delivery pipe 34 between the pulverized coal pipe 33 and the sampling injector 36 is blocked, the second valve 38 and the third valve 39 are closed, the first valve 37 is opened, and high-pressure air is input into the sampling injector 36 to back-blow into the pulverized coal pipe 33 to clear the delivery pipe 34 in this section.

[0064] Preferably, the first valve 37 , the second valve 38 and the third valve 39 are all automatic valves, such as pneumatic ball valves or electric ball valves, and are all connected to the control center 1 , and the automatic valves are controlled by the control center 1 .

[0065] Furthermore, a return-sample injector 29 is provided at the junction of the measuring chamber 23 and the return-sample pipe 35. This injector is connected to the pressure-regulating valve assembly 32. The return-sample injector 29 functions similarly to the sampling injector 36. Compressed air is fed into the return-sample injector 29, creating a negative pressure at the outlet of the measuring chamber 23. This draws out the pulverized coal from the measuring chamber 23 and transports it along the return-sample pipe 35 into the pulverized coal pipe 33. The sampling injector 36 works in conjunction with the return-sample injector 29 to allow pulverized coal to enter and exit the measuring chamber 23.

[0066] The sample delivery device 3 of the present invention can realize multi-channel automatic sample delivery, and the detection device 2 performs automatic detection on the coal powder in different channels. Since the present invention detects the coal powder based on the laser induced breakdown spectroscopy method, the detection speed is fast. Through the cooperation of multiple optical path switching mechanisms 24 in the detection device 2, the present invention can detect the coal powder in multiple coal powder pipes 33 in a relatively short time, thereby achieving the purpose of real-time grasp of the coal quality changes of multiple coal powders, effectively improving the detection efficiency and reducing the detection cost.

[0067] The embodiments provided by the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A multi-channel coal quality characteristics online detection system for pulverized coal pipes, characterized in that: include: Control Center (1); A sample delivery device (3) is connected to the control center (1); A detection device (2) comprises a laser (21), a spectrometer (22), a lens assembly, an optical path switching mechanism (24) and a measuring chamber (23), wherein a plurality of the measuring chambers (23) are connected to a sample delivery device (3), a plurality of the optical path switching mechanisms (24) are arranged between the laser (21) and the plurality of measuring chambers (23), and the optical path switching mechanisms (24) correspond to the measuring chambers (23) on a one-to-one basis; Along the optical path of the laser light emitted by the laser (21), a plurality of optical path switching mechanisms (24) are arranged from front to back; The lens assembly comprises a total reflection lens (25), a focusing lens group (26) and a light-collecting lens group (27); a total reflection lens (25) is provided in each optical path switching mechanism (24); a focusing lens group (26) is provided on the side of each measuring chamber (23); the focusing lens group (26) is located between the total reflection lens (25) and the measuring chamber (23); a light-collecting lens group (27) is further provided on the other side of each measuring chamber (23); and the spectrometer (22) is connected to the light-collecting lens group (27) via an optical fiber (28); The laser (21), the spectrometer (22) and the optical path switching mechanism (24) are all connected to the control center (1).

2. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 1 is characterized in that: A plurality of total reflection lenses (25) are arranged parallel to each other.

3. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 2 is characterized in that: The incident angles of the laser on the multiple total reflection mirrors (25) are all 45 degrees.

4. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 1 is characterized in that: For the same measuring chamber (23), the light-collecting lens group (27) is located on one side of the focusing lens group (26).

5. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 4 is characterized in that: The light-collecting lens group (27) is arranged adjacent to the focusing lens group (26).

6. The multi-channel coal quality characteristics online detection system for pulverized coal pipe according to any one of claims 1 to 5, characterized in that: The sample delivery device (3) comprises a compressed air source (31), a pressure regulating valve group (32) and a pulverized coal pipe (33). The compressed air source (31) is connected to the pressure regulating valve group (32), and the pressure regulating valve group (32) is connected to the control center (1). The number of the pulverized coal pipes (33) is the same as the number of the measuring chambers (23). A delivery pipe (34) and a sample return pipe (35) are provided between each pulverized coal pipe (33) and the corresponding measuring chamber (23). A sampling injector (36) is provided on the delivery pipe (34), and an air inlet of the sampling injector (36) is connected to the pressure regulating valve group (32).

7. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 6 is characterized in that: A first valve (37) is provided between the pulverized coal pipe (33) and the sampling injector (36), a second valve (38) is provided between the sampling injector (36) and the measuring chamber (23), and a third valve (39) is provided on the sample return pipe (35).

8. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 6 is characterized in that: A sample return injector (29) is provided at the connection between the measuring chamber (23) and the sample return pipe (35), and the sample return injector (29) is connected to the pressure regulating valve group (32).

9. The multi-channel coal quality characteristics online detection system for pulverized coal pipes according to claim 7, characterized in that: The first valve (37), the second valve (38) and the third valve (39) are all automatic valves, and are all connected to the control center (1).

10. A multi-channel on-line detection method for coal quality characteristics of a pulverized coal pipe (33), characterized in that: The detection is performed by using the multi-channel coal quality characteristics online detection system for pulverized coal pipes according to any one of claims 1 to 9 as follows: S1, the sample delivery device (3) delivers pulverized coal to all the measuring chambers (23) in the detection device (2), and a pulverized coal flow is formed in each measuring chamber (23); S2, the optical path switching mechanism (24) corresponding to the measuring chamber (23) to be tested controls the total reflection lens (25) to enter the laser optical path, and the remaining total reflection lenses (25) in front of the total reflection lens (25) leave the laser optical path; S3, the laser (21) emits a laser, which is reflected and focused on the coal powder flow in the center of the corresponding measuring chamber (23) by the focusing lens group (26), generating plasma at the focused position, and the plasma light signal is focused on the end face of the optical fiber (28) by the light receiving lens group (27) on the other side of the measuring chamber (23), and the optical fiber (28) transmits the light signal to the spectrometer (22) for photoelectric conversion, and the data converted by the spectrometer (22) is transmitted to the control center (1) for data analysis, thereby obtaining the coal quality characteristic data of the coal powder in the corresponding measuring chamber (23); S4. After completing step S3, if it is necessary to continue detecting the coal powder in other measuring chambers (23), repeat steps S2-S3; If there is no need to detect coal powder anymore, all the total reflection lenses (25) leave the laser light path and the detection device (2) stops detecting.

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