Primary air pulverized coal flow measurement device and method

Abstract

The present invention provides a primary air pulverized coal flow measurement device and method. The scheme is based on a photoelectric conversion method and combines the relationship between pulverized coal concentration and photoelectric intensity. By adopting a light beam with a certain spot diameter, the pulverized coal flow is measured throughout the entire pulverized coal pipeline. The measurement range is large, and the influence of uneven flow in the pulverized coal pipeline is small, which effectively improves the measurement accuracy. At the same time, the scheme is based on optical path division, and can simultaneously obtain important information such as pulverized coal concentration, pulverized coal flow rate and flow rate, which can reduce the number of instruments and equipment for separate measurements and simplify the acquisition process. Furthermore, the scheme performs pollution detection on the entire optical path and introduces a pollution coefficient to correct the collected photoelectric signal, which greatly alleviates or avoids measurement errors caused by lens pollution and other reasons, enhances the stability and practicality of the system, and improves the measurement accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to a primary air pulverized coal flow measurement device and method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] One of the cores of a power plant coal-fired boiler is its combustion system, which ensures that the pulverized coal is fully and evenly burned in the furnace, while effectively reducing the generation of harmful gases such as nitrogen oxides. It is one of the key links in thermal power energy conservation and emission reduction. Since there has been no reliable and effective means to measure the parameters of the coal entering the furnace of each burner and the combustion parameters in the furnace, the direct parameters of boiler combustion optimization are missing, resulting in little progress in combustion optimization in recent years. If the flow rate and concentration of the primary air pulverized coal in each burner are too different, the furnace cannot organize a good combustion, causing the flame center to deviate. In severe cases, it will cause coking, high-temperature corrosion, wear and increased oxide scale on the heating surface such as the water-cooled wall; the carbon content and slag discharge of fly ash will increase, the loss of incomplete combustion of gas will increase, the coal consumption will increase, and the combustion efficiency will decrease; which will in turn cause an increase in flue gas volume, overheating of the reheated steam, an increase in the amount of cooling water, and a decrease in thermal efficiency; NOx emissions will increase.

[0004] The inventors have found that the current adjustment of primary air and powder in thermal power plants is mainly to set the air volume through each primary air duct at the coal mill outlet in the cold state, and it does not change in the hot state. The disadvantage of this method is that the balance of air volume is not equal to the balance of powder volume, and the balance in the cold state is not equal to the balance in the hot state; furthermore, the influence of various factors during operation cannot be effectively eradicated, especially during low-load operation, the influence of air duct resistance is greatly increased, and these influences will aggravate the imbalance of flow between the primary air ducts, thereby aggravating the imbalance of combustion in the furnace. Summary of the invention

[0005] The present invention provides a primary air pulverized coal flow measurement device and method, so as to solve the problem that the traditional solution cannot accurately measure the pulverized coal flow, resulting in uneven combustion in the furnace.

[0006] According to a first aspect of an embodiment of the present invention, there is provided a primary air pulverized coal flow measurement device, comprising: a light generating unit, a light receiving unit, and a signal acquisition transmission and data analysis unit;

[0007] The light generating unit comprises a curved reflector, a light source and a first light guide which are arranged in sequence. The generated light beam passes through a first light source emission end lens group built in the first light guide, and then passes through a flat plate beam splitter, a first half-reflecting half-mirror and a second half-reflecting half-mirror in sequence, and then vertically enters the coal powder pipeline to obtain a first light beam carrying coal powder information; the reflected light beam of the flat plate beam splitter passes through the first reflector and the second light source emission end lens group built in the second light guide in sequence, and then vertically enters the coal powder pipeline to obtain a second light beam carrying coal powder information;

[0008] The light receiving unit comprises a third semi-reflective half-mirror and a fourth light guide tube with a second light receiving end lens group built in. The third semi-reflective half-mirror takes the first light beam as input and outputs the light beam to the first photoelectric sensor group through the third light guide tube with the first light receiving end lens group built in. The fourth light guide tube takes the second light beam as input and reaches the second photoelectric sensor group after passing through a second reflector.

[0009] The signal acquisition, transmission and data analysis unit is used to acquire signals from the first and second photoelectric sensor groups, and obtain the coal powder flow rate and flow rate based on the acquired signals.

[0010] Furthermore, the calculation of the coal powder flow rate is specifically as follows: the coal powder flow rate is obtained based on the distance between the first light beam and the second light beam, and the time difference when the first and second photoelectric sensor groups receive the same coal powder information; the calculation of the coal powder flow rate is specifically the product of the coal powder flow rate and the coal powder concentration per unit time, wherein the coal powder concentration is based on the functional relationship between the coal powder concentration and the light intensity, and the coal powder concentration is obtained by substituting the photoelectric signal value collected by the first photoelectric sensor.

[0011] Furthermore, the reflected light beam of the first semi-reflecting and semi-mirror lens enters the coal powder pipeline vertically after being reflected by multi-stage reflectors and processed by the second semi-reflecting and semi-mirror lens, thereby obtaining a third light beam carrying coal powder information; the third light beam reaches the third photoelectric sensor group after being processed by multi-stage reflectors and the third semi-reflecting and semi-mirror lens.

[0012] Furthermore, by performing contamination detection on the optical path from the light source to the third semi-reflective half-mirror lens based on the third light beam received by the third photoelectric sensor group, a contamination coefficient is determined based on the detection result, and the photoelectric signal value obtained based on the first photoelectric sensor group is corrected based on the contamination coefficient.

[0013] Furthermore, the calculation of the pollution coefficient is specifically: a reference value of the photoelectric signal received by the third photoelectric sensor group and a photoelectric signal value received by the third photoelectric sensor group during actual measurement; wherein, the reference value is the photoelectric signal value received by the third photoelectric sensor group in a dust-free working state.

[0014] Furthermore, the reflected light beam of the flat plate spectroscope is a parallel light beam, and its direction is parallel to the coal powder pipeline; the parallel light beam is turned to be parallel to the direction of the first light guide after passing through the first reflector, and enters the coal powder pipeline vertically after passing through the second light source emission end lens group in the second light guide.

[0015] Furthermore, the second light beam passes through the second light receiving end lens group built into the fourth light guide tube, and the parallel light beam is modulated into a convergent light beam, which is received by the second photoelectric sensor group.

[0016] Furthermore, the light source is arranged at the front end of the arc reflector, and the scattered light emitted by the light source is superimposed with the light emitted by the arc reflector to serve as the input of the first light guide.

[0017] Furthermore, the light source is a white light source and is powered by a DC regulated power supply.

[0018] According to a second aspect of an embodiment of the present invention, a method for measuring the flow rate of primary air pulverized coal is provided. The method is based on the above-mentioned device for measuring the flow rate of primary air pulverized coal. The method comprises:

[0019] Starting the light source to generate a first light beam, a second light beam and a third light beam;

[0020] Based on the first light beam, the second light beam and the third light beam, a first photoelectric signal value, a second photoelectric signal value and a third photoelectric signal value are obtained through a first photoelectric sensor group, a second photoelectric sensor group and a third photoelectric sensor group;

[0021] Based on the obtained first photoelectric signal value and the second photoelectric signal value, determine the time difference when receiving the same coal powder information, and combine the distance between the first light beam and the second light beam to obtain the coal powder flow rate;

[0022] A pollution coefficient is obtained based on the third photoelectric signal value combined with the reference value;

[0023] Correcting the first photoelectric signal value based on the obtained pollution coefficient, and determining the coal powder concentration based on the corrected photoelectric signal value and a pre-constructed relationship function between the coal powder concentration and the photoelectric intensity;

[0024] The pulverized coal flow rate is determined based on the pulverized coal concentration and the pulverized coal flow rate.

[0025] One or more of the above technical solutions have the following beneficial effects:

[0026] The present invention provides a primary air pulverized coal flow measurement device and method. The scheme is based on a photoelectric conversion method, combined with the relationship between pulverized coal concentration and photoelectric intensity, and uses a light beam with a certain spot diameter to penetrate the entire pulverized coal pipeline to measure the pulverized coal flow. The measurement range is large, and the influence of uneven flow in the pulverized coal pipeline is small, which effectively improves the measurement accuracy.

[0027] The scheme is based on optical path division, and can simultaneously obtain important information such as coal powder concentration, coal powder flow velocity and flow rate, which can reduce the number of instruments and equipment for separate measurements and simplify the acquisition process;

[0028] The scheme detects the pollution of the entire optical path and introduces the pollution coefficient to correct the collected photoelectric signal, which greatly alleviates or avoids the measurement error caused by lens pollution and other reasons, enhances the stability and practicality of the system, and improves the measurement accuracy.

[0029] The scheme adopts a white light source with a wide spectral range. By adding a bandpass filter, the central wavelength and bandwidth of the filter can be flexibly selected, and the adaptability to the measurement target is strong;

[0030] The scheme adopts a photoelectric conversion method, which has a fast collection speed and strong real-time performance. It is suitable for measuring low-concentration coal powder flow in conjunction with a high-sensitivity photoelectric sensor and can better characterize the flow state of coal powder. At the same time, the components and elements used in the scheme of the present invention are all standard parts or commonly used devices, and there are no supply or processing difficulties. The stability is also guaranteed, and the practicality is high and the cost is low.

[0031] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0033] Figure 1 It is a structural schematic diagram of the primary air pulverized coal flow measurement device described in an embodiment of the present invention;

[0034] Figure 2 This is a flow chart of the primary air pulverized coal flow measurement method described in an embodiment of the present invention;

[0035] Among them, 1. light generating unit; 2. light receiving unit; 3. signal acquisition transmission and data analysis unit; 11. arc reflector; 12. light source; 13. first light guide; 14. first light source emission end lens group; 15. flat plate beam splitter; 16. first half-reflecting half-mirror; 17. second half-reflecting half-mirror; 18. second light guide; 19. second light source emission end lens group; 110. first reflector; 111. third reflector; 112. fourth reflector; 113. fifth reflector Mirror; 21, first light receiving unit; 22, second light receiving unit; 23, third light receiving unit; 211, third semi-reflective mirror; 212, first light receiving end lens group; 213, third light guide; 214, first photoelectric sensor group; 221, fourth light guide; 222, second light receiving end lens group; 223, second reflector; 224, second photoelectric sensor group; 231, sixth reflector; 232, seventh reflector; 233, third photoelectric sensor group. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0038] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0039] In one or more embodiments, Figure 1 As shown, this embodiment provides a primary air pulverized coal flow measurement device, including: a light generating unit 1, a light receiving unit 2, and a signal acquisition transmission and data analysis unit 3;

[0040] The light generating unit 1 comprises a curved reflector 11, a light source 12 and a first light guide 13 which are arranged in sequence. The generated light beam passes through a first light source emission end lens group 14 built into the first light guide 13, and then passes through a flat plate beam splitter 15, a first half-reflecting half-mirror 16 and a second half-reflecting half-mirror 17 in sequence, and then vertically enters the coal powder pipeline to obtain a first light beam carrying coal powder information; the reflected light beam of the flat plate beam splitter 15 passes through a first reflector 110 and a second light source emission end lens group 19 built into the second light guide 18 in sequence, and then vertically enters the coal powder pipeline to obtain a second light beam carrying coal powder information;

[0041] Among them, the lens group at the light source emitting end has the function of modulating the scattered light emitted by the light source into a parallel light beam, and can also adjust the light beam intensity and select a specific wavelength by adding optical attenuation plates and bandpass filters.

[0042] The light receiving unit 2 includes a third semi-reflective mirror 211 and a fourth light pipe 221 with a second light receiving end lens group 222 built in. The third semi-reflective mirror 211 takes the first light beam as input, and outputs the light beam to the first photoelectric sensor group 214 through a third light pipe 213 with a first light receiving end lens group 212 built in. The fourth light pipe 221 takes the second light beam as input, and reaches the second photoelectric sensor group 224 after passing through a second reflector 223.

[0043] The signal acquisition, transmission and data analysis unit 3 is used to acquire signals from the first and second photoelectric sensor groups, and obtain the coal powder flow rate and flow rate based on the acquired signals.

[0044] In a specific implementation, the calculation of the coal powder flow rate is specifically as follows: the coal powder flow rate is obtained based on the distance between the first light beam and the second light beam, and the time difference when the first and second photoelectric sensor groups receive the same coal powder information; the calculation of the coal powder flow rate is specifically the product of the coal powder flow rate and the coal powder concentration per unit time, wherein the coal powder concentration is based on the functional relationship between the coal powder concentration and the light intensity, and the coal powder concentration is obtained by substituting the photoelectric signal value collected by the first photoelectric sensor.

[0045] In a specific implementation, the reflected light beam of the first semi-reflecting and semi-mirror lens enters the coal powder pipeline vertically after being reflected by multi-stage reflectors and processed by the second semi-reflecting and semi-mirror lens to obtain a third light beam carrying coal powder information; the third light beam reaches the third photoelectric sensor group after being processed by multi-stage reflectors and the third semi-reflecting and semi-mirror lens.

[0046] In one or more embodiments, contamination detection is performed on the optical path from the light source to the third semi-reflective half-mirror lens based on the third light beam received by the third photoelectric sensor group, a contamination coefficient is determined based on the detection result, and the photoelectric signal value obtained based on the first photoelectric sensor group is corrected based on the contamination coefficient.

[0047] The calculation of the pollution coefficient is specifically: the reference value of the photoelectric signal received by the third photoelectric sensor group and the photoelectric signal value received by the third photoelectric sensor group during the actual measurement process; wherein the reference value is the photoelectric signal value received by the third photoelectric sensor group in a dust-free working state.

[0048] In a specific implementation, the reflected light beam of the flat plate spectroscope is a parallel light beam, and its direction is parallel to the coal powder pipeline; the parallel light beam is turned to be parallel to the direction of the first light guide after passing through the first reflector, and enters the coal powder pipeline vertically after passing through the second light source emission end lens group in the second light guide.

[0049] In a specific implementation, the second light beam passes through the second light receiving end lens group built into the fourth light guide tube, and the parallel light beam is modulated into a convergent light beam, which is received by the second photoelectric sensor group.

[0050] In a specific implementation, the light source is disposed at the front end of the arc reflector, and the scattered light emitted by the light source is superimposed with the light emitted by the arc reflector to serve as the input of the first light guide.

[0051] Specifically, Figure 1 As shown, the light generating unit specifically includes the following structure:

[0052] The voltage-stabilized electric light source 12 in the light generating unit 1 is powered by a DC voltage-stabilized power supply, and the power supply and power are determined according to the type of light source and the light intensity requirement; the light source 12 is located at the front end of the arc reflector 11, and the distance between the center of the light source 12 and the arc reflector 11 is equal to or less than the radius of the arc reflector 11; the scattered light emitted by the light source 12 is superimposed with the reflected light of the arc reflector 11 and passes through the light source emission end lens group 14 arranged in the first light guide 13; the light beam adjusted by the light source emission lens group 14 is a parallel light beam, which passes through the flat plate beam splitter 15, the half-reflecting half-mirror 16, and the half-reflecting half-mirror 17 in sequence and then directly passes through the coal powder pipeline to obtain the first light beam carrying coal powder information;

[0053] The DC regulated power supply is continuously adjustable, and the set stable output voltage is within 36V; the flat-plate spectroscope 15 is 45 degrees to the light beam direction of the first light pipe 13, and is a proportional spectroscopic method, such as in the visible light range of 400-700nm, the distribution ratio of the direct part to the reflected part is 4:1; the first semi-reflective half-mirror 16 and the second semi-reflective half-mirror 17, the distribution ratio of the direct part to the reflected part is 1:1, and can be flat-plate type or prism type, preferably flat-plate type; the first semi-reflective half-mirror 16 and the second semi-reflective half-mirror 17 are 45 degrees to the light beam direction of the first light pipe 13;

[0054] The light source emission end lens group 14 is provided with a collimating lens group, which is used to modulate the incident stray light into a parallel light beam. The light source emission end lens group is provided with a visible light attenuation plate and a bandpass filter slot, and an attenuation plate and a filter can be optionally installed to adjust the light intensity and select the wavelength and bandwidth of the light;

[0055] Furthermore, another parallel light beam after passing through the flat plate beam splitter 15 is perpendicular to the direct direction and parallel to the coal powder pipeline. After passing through the first reflector 19, it returns 90 degrees and enters the second light guide 18. The direction of the second light guide 18 is parallel to the light guide 13 and passes through the coal powder pipeline.

[0056] Furthermore, after passing through the first semi-reflecting half-mirror 16, another light beam is emitted perpendicular to the first light pipe 13, after passing through the first light path after being folded back, it is emitted perpendicular to the first light pipe 13 after passing through the second semi-reflecting half-mirror 17, and then after passing through the second light path after being folded back, it is emitted perpendicular to the third light pipe 213 after passing through the third semi-reflecting half-mirror 211, and is received by the third light receiving unit 23; the function of the third light receiving unit 23 is to calibrate the light intensity signal in real time, so as to provide a basis for correcting the measured value of the coal powder concentration;

[0057] Specifically, Figure 1 As shown, the light receiving unit specifically includes the following structure:

[0058] The first light receiving unit 21 is the main measurement channel for coal powder flow measurement, and is characterized in that the effective diameter of the parallel light beam after light source modulation is relatively large, such as a parallel light beam diameter of 5-25 mm, which can greatly increase the amount of coal powder information and reduce the measurement error caused by uneven flow;

[0059] The half-reflective half-mirror 211 and the first light receiving end lens group 212 in the first light receiving unit 21 are arranged in sequence in the third light guide tube 213 along the light beam emission direction; the light receiving end lens group 212 is used to modulate the parallel light beam into a convergent light beam, and is received by the first photoelectric sensor group 214 in the first light receiving unit 21.

[0060] Another parallel light beam after passing through the flat plate beam splitter 15 is perpendicular to the direct direction and parallel to the pulverized coal pipeline. After passing through the first reflector 19, it turns back 90 degrees and enters the second light guide 18 in a direction parallel to the first light guide 13. It passes through the pulverized coal pipeline and passes through the second light receiving end lens group 222 provided in the fourth light guide 221. The parallel light beam is modulated into a convergent light beam and is received by the second photoelectric sensor group 224 in the second light receiving unit 22 through the second reflector 223.

[0061] In one or more embodiments, the 90-degree folding method of the first reflector may be an optical fiber method; the light emitting end lens group may not be provided in the second light guide tube; and the light receiving end lens group may not be provided in the fourth light guide tube.

[0062] In a specific implementation, the 90-degree return mode is a hard tube mode, and an optical fiber mode can be selected; the second light receiving unit 22 is used for coal powder flow velocity measurement. According to the relevant speed measurement principle, the same fluid medium is captured at two positions, and the flow velocity can be measured by the time difference and distance between the two positions; the coal powder flow velocity measurement method in this implementation is: the second light receiving unit 22 detects the information of the same coal powder received by the first light receiving unit 21, and calculates the coal powder flow velocity by analyzing the time difference of the same coal powder information of the first and second receiving units and the distance between the center lines of the first light guide 13 and the second light guide 18;

[0063] In one or more embodiments, the second light source emitting end lens group 110 may not be provided in the light guide 18; the second light receiving end lens group 222 may not be provided in the fourth light guide 221; the spot diameter of the parallel light beam of the second light guide 18 and the fourth light guide 221 may be equal to the spot diameter of the first light guide 13 and the third light guide 213, or may be smaller, such as the inner diameter ratio of the second light guide 18, the fourth light guide 221 and the first light guide 13, the third light guide 213 is 1:1 or 1:2.

[0064] In a specific implementation, another light beam perpendicular to the first light pipe 13 is emitted after passing through the first half-reflecting half-mirror 16, and after passing through the first light path after the return, it is emitted perpendicular to the first light pipe 13 after passing through the second half-reflecting half-mirror 17, and then after passing through the second light path after the return, it is emitted perpendicular to the third light pipe 213 after passing through the third half-reflecting half-mirror 211, and is received by the third photoelectric sensor group 233 in the third light receiving unit 23; the function of the third light receiving unit 23 is to verify the light intensity signal in real time, and provide a basis for correcting the measured value of the coal powder concentration. Among them, the light beam direction of the third half-reflecting half-mirror 211 and the light pipe 213 is 45 degrees; the distribution ratio of the direct part and the reflected part is 1:1, and it can be flat or prism-type, preferably flat.

[0065] In one or more embodiments, the light beam vertically emitted from the first semi-reflecting half-mirror and the light beam vertically incident on the second semi-reflecting half-mirror can be reflected by two vertically arranged mirrors and reflected twice, or by optical fiber connection; the light beam vertically emitted from the second semi-reflecting half-mirror and the light beam vertically incident on the third semi-reflecting half-mirror can be reflected by two vertically arranged mirrors and reflected twice, or by optical fiber connection.

[0066] The optical signals of the first light receiving unit 21, the second light receiving unit 22 and the third light receiving unit 23 are respectively transmitted to the photoelectric sensor group 214, the photoelectric sensor group 224 and the photoelectric sensor group 233, and the electrical signals outputted after the signal amplification and noise reduction circuit are connected to the PC end through the data acquisition card; the data acquisition card and the PC end are connected by RS485, and the signal amplification and noise reduction circuit, the data acquisition card, the connection between the data acquisition card and the PC end, the PC end and the analysis and calculation software together constitute the signal acquisition transmission and data analysis unit 3;

[0067] The light generating unit and the light receiving unit are both provided with a mounting seat, and the mounting seat is connected to the coal powder pipeline through the first light guide, the second light guide, the third light guide and the fourth light guide. The connection method of the light guide and the coal powder pipeline is: a through hole is made in the radial section of the coal powder pipeline at a distance of 180 degrees, and the first light guide 13 and the third light guide 213 are vertically connected to the coal powder pipeline through a flange; along the flow direction of the coal powder, a certain distance from the through hole is made, and the second light guide 18 and the fourth light guide 221 are vertically connected to the coal powder pipeline through a flange; the coal powder pipeline openings of the first light guide and the second light guide 12 are on the same side, and the coal powder pipeline openings of the third light guide and the fourth light guide are on the other side, and the line connecting the center lines of the openings on the same side is parallel to the center line of the coal powder pipeline; according to the requirements of installation, protection, and measurement accuracy, the connection of the light guide and the coal powder pipeline can be a connection method in which the end of the light guide is connected to the coal powder pipeline, or a connection method in which a part of the light guide extends into the coal powder pipeline.

[0068] In a specific implementation, the first light receiving unit and the second light receiving unit are used to collect photoelectric signals to obtain real-time coal powder concentration information, and the coal powder flow rate is obtained through the correlation, distance, time difference and other parameters of the photoelectric signal fluctuations of the first light receiving unit and the second light receiving unit; the coal powder flow rate information is obtained through the coal powder concentration information obtained by the first receiving unit and the calculated coal powder flow rate;

[0069] The third light receiving unit is used for detecting contamination of the light path from the light source to the third semi-reflective half-mirror, including the stability of the voltage-stabilized power supply, the stability of the light source, the contamination of the light source reflector, the contamination of the second semi-reflective half-mirror, and the contamination of the third semi-reflective half-mirror. Factors affecting the light intensity are ultimately reflected in the photoelectric signal of the third light receiving unit.

[0070] In this embodiment, it is necessary to increase the corresponding purge gas to prevent the coal powder from contaminating the second semi-reflecting half-mirror 17 and the third semi-reflecting half-mirror 211.

[0071] In one or more embodiments, corresponding to the above system, such as Figure 2 As shown, this embodiment provides a primary air pulverized coal flow measurement method, which is based on the primary air pulverized coal flow measurement device mentioned above, and the method includes:

[0072] Starting the light source to generate a first light beam, a second light beam and a third light beam;

[0073] Based on the first light beam, the second light beam and the third light beam, a first photoelectric signal value, a second photoelectric signal value and a third photoelectric signal value are obtained through a first photoelectric sensor group, a second photoelectric sensor group and a third photoelectric sensor group;

[0074] Based on the obtained first photoelectric signal value and the second photoelectric signal value, determine the time difference when receiving the same coal powder information, and combine the distance between the first light beam and the second light beam to obtain the coal powder flow rate;

[0075] A pollution coefficient is obtained based on the third photoelectric signal value combined with the reference value;

[0076] Correcting the first photoelectric signal value based on the obtained pollution coefficient, and determining the coal powder concentration based on the corrected photoelectric signal value and a pre-constructed relationship function between the coal powder concentration and the photoelectric intensity;

[0077] The pulverized coal flow rate is determined based on the pulverized coal concentration and the pulverized coal flow rate.

[0078] In a specific implementation, measurement information of the first light receiving unit 21, the second light receiving unit 22 and the third light receiving unit 23 are collected simultaneously, wherein the third light receiving unit 23 is used as verification information, and firstly, it is determined whether the actual measurement value of the third light receiving unit 23 is equal to the reference value. If they are equal, it means there is no pollution, and then the coal powder concentration information is directly obtained based on the measurement data of the first light receiving unit and the second light receiving unit, and the coal powder flow rate and flow rate are calculated; if they are not equal, firstly, it is determined whether the difference between the two is greater than a set threshold, such as 10%. If it is greater than the set threshold, it is considered that the light path is seriously polluted and the coal powder flow rate cannot be accurately measured, and the detection system will issue an early warning and generate a corresponding fault prompt; if it is less than or equal to the set threshold, the actual measurement value of the first light receiving unit is corrected according to the correction expression, and the corrected value is compared with the measurement data of the second light receiving unit to obtain the coal powder concentration information, and the coal powder flow rate and flow rate are calculated.

[0079] The value of the set threshold value is related to the coal powder flow measurement range, the photoelectric conversion sensor and the photoelectric signal amplifier, and the coal powder flow measurement accuracy.

[0080] like Figure 2 As shown, the correction process is as follows:

[0081] The system pre-calibrates the photoelectric information of the third light receiving unit in a dust-free working state and uses it as a reference value; the dust-free working state is that the light source is in a pure and dust-free state at the rated working voltage, the arc reflector 11, the first light pipe 13, the second light pipe 18, the second semi-reflective half-mirror 17, and the third semi-reflective half-mirror 211;

[0082] After coal powder passes through, the photoelectric signal obtained by the third light receiving unit is the actual measurement value. By comparing the calibrated reference value with the actual measurement value, the relative contamination degree of the light path is obtained, and based on this, the actual value measured by the first light receiving unit is corrected accordingly.

[0083] The corrected expression is as follows:

[0084] e=E i0 / E i

[0085] E A =e*E A0

[0086] Where, e is the pollution coefficient; E A is the actual correction value, i.e., the correction value of the actual measurement process of the first light receiving unit; E i To verify the actual measured value, that is, the actual measured value obtained by the third light receiving unit during the actual measurement process; E i0 is the calibration reference value, that is, the reference value measured by the third light receiving unit in a dust-free state, E A0 is the measured value obtained by the first light receiving unit.

[0087] In one or more embodiments, a threshold is set for the pollution coefficient e, and the threshold is related to the coal powder flow measurement range, the photoelectric conversion sensor, the photoelectric signal amplifier, and the measurement accuracy. If it is greater than the set threshold, it is considered that the light path is seriously polluted and the coal powder concentration cannot be accurately measured. The detection system will issue an early warning and generate a corresponding fault prompt.

[0088] Those skilled in the art will appreciate that the units, i.e., algorithm steps, of the various examples described in the present embodiment can be implemented in electronic hardware or in a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Primary air pulverized coal flow measurement device, characterized in that: include: Light generating unit, light receiving unit, and signal acquisition transmission and data analysis unit; The light generating unit comprises a curved reflector, a light source and a first light guide which are arranged in sequence. The generated light beam passes through a first light source emission end lens group built in the first light guide, and then passes through a flat plate beam splitter, a first half-reflecting half-mirror and a second half-reflecting half-mirror in sequence, and then vertically enters the coal powder pipeline to obtain a first light beam carrying coal powder information; the reflected light beam of the flat plate beam splitter passes through the first reflector and the second light source emission end lens group built in the second light guide in sequence, and then vertically enters the coal powder pipeline to obtain a second light beam carrying coal powder information; The light receiving unit comprises a third semi-reflective half-mirror and a fourth light guide tube with a second light receiving end lens group built in. The third semi-reflective half-mirror takes the first light beam as input and outputs the light beam to the first photoelectric sensor group through the third light guide tube with the first light receiving end lens group built in. The fourth light guide tube takes the second light beam as input and reaches the second photoelectric sensor group after passing through a second reflector. The signal acquisition, transmission and data analysis unit is used to acquire signals from the first and second photoelectric sensor groups, and obtain the coal powder flow rate and flow rate based on the acquired signals.

2. The primary air pulverized coal flow measurement device according to claim 1, characterized in that: The calculation of the coal powder flow rate is specifically as follows: the coal powder flow rate is obtained based on the distance between the first light beam and the second light beam, and the time difference when the first and second photoelectric sensor groups receive the same coal powder information; the calculation of the coal powder flow rate is specifically the product of the coal powder flow rate and the coal powder concentration per unit time, wherein the coal powder concentration is based on the functional relationship between the coal powder concentration and the light intensity, and the coal powder concentration is obtained by substituting the photoelectric signal value collected by the first photoelectric sensor.

3. The primary air pulverized coal flow measurement device according to claim 1, characterized in that: The reflected light beam of the first semi-reflecting and semi-mirror lens enters the coal powder pipeline vertically after being reflected by multi-stage reflectors and processed by the second semi-reflecting and semi-mirror lens, thereby obtaining a third light beam carrying coal powder information; the third light beam reaches the third photoelectric sensor group after being processed by multi-stage reflectors and the third semi-reflecting and semi-mirror lens.

4. The primary air pulverized coal flow measurement device according to claim 3, characterized in that: Based on the third light beam received by the third photoelectric sensor group, a contamination detection is performed on the optical path from the light source to the third semi-reflective half-mirror lens, a contamination coefficient is determined based on the detection result, and the photoelectric signal value obtained based on the first photoelectric sensor group is corrected based on the contamination coefficient.

5. The primary air pulverized coal flow measurement device according to claim 4, characterized in that: The calculation of the pollution coefficient is specifically: the reference value of the photoelectric signal received by the third photoelectric sensor group and the photoelectric signal value received by the third photoelectric sensor group during the actual measurement process; wherein, the reference value is the photoelectric signal value received by the third photoelectric sensor group in a dust-free working state.

6. The primary air pulverized coal flow measurement device according to claim 1, characterized in that: The reflected light beam of the flat plate spectroscope is a parallel light beam, and its direction is parallel to the coal powder pipeline; the parallel light beam is turned to be parallel to the direction of the first light guide after passing through the first reflector, and enters the coal powder pipeline vertically after passing through the second light source emission end lens group in the second light guide.

7. The primary air pulverized coal flow measurement device according to claim 1, characterized in that: The second light beam passes through the second light receiving end lens group built into the fourth light guide tube, and the parallel light beam is modulated into a convergent light beam, which is received by the second photoelectric sensor group.

8. The primary air pulverized coal flow measurement device according to claim 1, characterized in that: The light source is arranged at the front end of the arc reflector, and the scattered light emitted by the light source is superimposed with the light emitted by the arc reflector as the input of the first light guide.

9. The primary air pulverized coal flow measurement device according to claim 1, characterized in that: The light source is a white light source and is powered by a DC stabilized power supply.

10. A method for measuring the primary air pulverized coal flow rate, characterized in that: Based on the primary air pulverized coal flow measurement device according to any one of claims 1 to 9, the method comprises: Starting the light source to generate a first light beam, a second light beam and a third light beam; Based on the first light beam, the second light beam and the third light beam, a first photoelectric signal value, a second photoelectric signal value and a third photoelectric signal value are obtained through a first photoelectric sensor group, a second photoelectric sensor group and a third photoelectric sensor group; Based on the obtained first photoelectric signal value and the second photoelectric signal value, determine the time difference when receiving the same coal powder information, and combine the distance between the first light beam and the second light beam to obtain the coal powder flow rate; A pollution coefficient is obtained based on the third photoelectric signal value combined with the reference value; Correcting the first photoelectric signal value based on the obtained pollution coefficient, and determining the coal powder concentration based on the corrected photoelectric signal value and a pre-constructed relationship function between the coal powder concentration and the photoelectric intensity; The pulverized coal flow rate is determined based on the pulverized coal concentration and the pulverized coal flow rate.

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