Online monitoring and optimizing system and method for thermal ignition distance of power station boiler burner

Abstract

The invention discloses an online monitoring and optimizing system and method for the thermal ignition distance of a power station boiler burner. The online monitoring and optimizing system comprises a high-temperature-resistant temperature measuring element, a telescopic device, a guide rail, the burner, a central processing unit, a burner secondary air volume adjusting mechanism, a burner secondary air rotational flow intensity adjusting mechanism and a coal mill. The high-temperature-resistant temperature measuring element is fixed to the telescopic device, the telescopic device is located on the guide rail, and the high-temperature-resistant temperature measuring element penetrates through the combustor. The central processing unit is connected with the control end of the telescopic device, the output end of the high-temperature-resistant temperature measuring element, the control end of the combustor secondary air volume adjusting mechanism, the control end of the combustor secondary air rotational flow intensity adjusting mechanism and the control end of the coal mill, an outlet of the coal mill is connected with the combustor, and an outlet of the coal mill is connected with the high-temperature-resistant temperature measuring element. The combustor secondary air quantity adjusting mechanism and the combustor secondary air rotational flow intensity adjusting mechanism are both arranged on the combustor. The system and the method can measure and optimize the thermal state ignition distance of the combustor of the power station boiler on line.

Description

Technical Field

[0001] The invention relates to an online monitoring and optimization system and method, and in particular to an online monitoring and optimization system and method for the hot ignition distance of a power station boiler burner. Background Art

[0002] The hot ignition distance of a power plant boiler burner is one of the most core factors affecting the quality of the boiler's combustion organization, and is one of the core factors affecting the safety and economy of boiler operation. If the ignition distance is too short, the burner is prone to flashback, resulting in coking and burning of the burner nozzle; if the ignition distance is too long, the burner is prone to de-ignition, resulting in unstable combustion or even fire extinguishing. The optimal ignition distance of burners of different boiler types, different burners, different loads, and different coal qualities is not the same. Due to the complex structure of the burner nozzle and the complex measurement environment inside the furnace, there is currently no mature online monitoring and real-time optimization and adjustment system for the hot ignition distance of power plant boiler burners at home and abroad.

[0003] At present, the coal quality of domestic thermal power units is complex and changeable, and the load change rate is getting faster and faster. In addition, with the implementation of the deep peak-shaving policy, the deep load regulation of power station boilers is getting lower and lower, which puts higher requirements on boiler combustion safety. The hot ignition distance of the burner is one of the most core parameters to characterize the combustion stability and state. The ability to scientifically realize the online monitoring and real-time optimization and adjustment of the hot ignition distance of power station boiler burners is of great promotion significance. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an online monitoring and optimization system and method for the hot ignition distance of a power plant boiler burner. The system and method can measure and optimize the hot ignition distance of a power plant boiler burner online.

[0005] To achieve the above-mentioned purpose, the present invention discloses an online monitoring and optimization system for the hot ignition distance of a power station boiler burner, comprising a high temperature resistant temperature measuring element, a telescopic device, a guide rail, a burner, a central processing unit, a burner secondary air volume adjustment mechanism, a burner secondary air swirl intensity adjustment mechanism and a coal mill;

[0006] The high temperature resistant temperature measuring element is fixed on the telescopic device, and the telescopic device is located on the guide rail, and the high temperature resistant temperature measuring element passes through the burner;

[0007] The central processing unit is connected to the control end of the telescopic device, the output end of the high-temperature resistant temperature measuring element, the control end of the burner secondary air volume adjustment mechanism, the control end of the burner secondary air swirl intensity adjustment mechanism and the control end of the coal mill, wherein the outlet of the coal mill is connected to the burner, and the burner secondary air volume adjustment mechanism and the burner secondary air swirl intensity adjustment mechanism are both arranged on the burner.

[0008] Furthermore, it also includes a measuring device cooling system, wherein the measuring device cooling system includes an instrument compressed air pipe and an air cooling sleeve;

[0009] An instrument compressed air inlet regulating valve is installed on the instrument compressed air pipe, the instrument compressed air pipe is connected to the air cooling sleeve, the high temperature resistant temperature measuring element is placed in the air cooling sleeve, and the probe of the high temperature resistant temperature measuring element extends out of the air cooling sleeve.

[0010] Furthermore, the high temperature resistant temperature measuring element is connected to the central processing unit via a data transmission line.

[0011] Furthermore, the central processing unit is connected to the burner secondary air volume adjustment mechanism via a first control cable; the central processing unit is connected to the burner secondary air swirl intensity adjustment mechanism via a second control cable.

[0012] Furthermore, the central processing unit is connected to the control end of the telescopic device through a third control cable.

[0013] The present invention discloses an online monitoring and optimization method for hot ignition distance of a power station boiler burner, comprising the following steps:

[0014] Control the telescopic device to move on the guide rail so that the probe of the high temperature resistant temperature measuring element moves toward the boiler side. During the movement, the temperature distribution of the primary air-powder airflow in a predetermined interval is measured by the probe of the high temperature resistant temperature measuring element. The ignition front of the burner is obtained according to the temperature distribution law of the primary air-powder airflow in the predetermined interval, and the ignition distance of the burner is determined according to the ignition front of the burner.

[0015] Determine whether the ignition distance of the burner is within a preset distance range. When the ignition distance of the burner is not within the preset distance range, control the burner secondary air volume adjustment mechanism, the burner secondary air swirl intensity adjustment mechanism and the coal mill to make the ignition distance of the burner within the preset distance range.

[0016] Furthermore, the burner is a swirl burner or a direct current burner.

[0017] Furthermore, when the burner is a swirl burner, when the ignition distance of the burner exceeds the preset maximum ignition distance, the internal secondary air flow rate, the swirl intensity of the internal secondary air, the flow rate of the external secondary air and the swirl intensity of the external secondary air of the burner are increased, and / or the primary air-to-coal ratio and the fineness of the coal powder of the coal mill are reduced;

[0018] When the ignition distance of the burner is less than the preset minimum ignition distance, the internal secondary air flow rate, the swirl intensity of the internal secondary air, the flow rate of the external secondary air and the swirl intensity of the external secondary air of the burner are reduced, and / or the primary air-to-coal ratio and coal powder fineness of the coal mill are increased.

[0019] Furthermore, when the burner is a direct current burner, when the ignition distance of the burner exceeds the preset maximum ignition distance, the auxiliary sealing flow rate and the peripheral wind flow rate of the burner are reduced, and / or the primary air-to-coal ratio and the coal powder fineness of the coal mill are reduced;

[0020] When the burner is a direct current burner, when the ignition distance of the burner is less than the preset minimum ignition distance, the auxiliary sealing flow and the peripheral wind flow of the burner are increased, and / or the primary air-to-coal ratio and the coal powder fineness of the coal mill are reduced.

[0021] Furthermore, the burner ignition distance test range is 0-1000mm;

[0022] The optimized ignition distance of the burner is 100mm-500mm.

[0023] The present invention has the following beneficial effects:

[0024] During specific operation, the system and method for online monitoring and optimization of hot ignition distance of a power station boiler burner described in the present invention measures the temperature distribution of the primary air-powder airflow within a predetermined interval through a probe of a high-temperature resistant temperature measuring element, and determines the ignition distance of the burner according to the temperature distribution law of the primary air-powder airflow within the predetermined interval. At the same time, the ignition distance is optimized by using a coal mill, a burner secondary air volume adjustment mechanism, and a burner secondary air swirl intensity adjustment mechanism. The operation is simple and the practicability is extremely strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting 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 an improper limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is a structural diagram of the present invention.

[0027] Among them, 1 is a guide rail, 2 is a telescopic device, 3 is an instrument compressed air inlet regulating valve, 4 is an instrument compressed air pipe, 5 is a burner, 6 is an air-cooled sleeve, 7 is a high-temperature resistant temperature measuring element, 8 is a third control cable, 9 is a data transmission line, 10 is a central processing unit, 11 is a first control cable, 12 is a second control cable, 13 is a burner secondary air volume adjustment mechanism, 14 is a burner secondary air swirl intensity adjustment mechanism, and 15 is a coal mill. DETAILED DESCRIPTION

[0028] 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 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.

[0029] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0031] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0032] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0033] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0036] Embodiment 1

[0037] refer to Figure 1 The on-line monitoring and optimization system for hot ignition distance of power station boiler burners described in the present invention comprises a guide rail 1, a telescopic device 2, an instrument compressed air inlet regulating valve 3, an instrument compressed air pipe 4, a burner 5, an air-cooling sleeve 6, a high-temperature resistant temperature measuring element 7, a third control cable 8, a data transmission line 9, a central processing unit 10, a first control cable 11, a second control cable 12, a burner secondary air volume adjustment mechanism 13, a burner secondary air swirl intensity adjustment mechanism 14 and a coal mill 15.

[0038] The high temperature resistant temperature measuring element 7 is fixed on the telescopic device 2, and the telescopic device 2 is located on the guide rail 1, and the telescopic device 2 can perform reciprocating motion on the guide rail 1; the instrument compressed air pipe 4 is installed with an instrument compressed air inlet regulating valve 3, and the instrument compressed air pipe 4 is connected to the air cooling sleeve 6, and the air cooling sleeve 6 is used to adjust the flow rate of the instrument compressed air to meet the system cooling requirements; the high temperature resistant temperature measuring element 7 is placed in the air cooling sleeve 6, and the probe of the high temperature resistant temperature measuring element 7 extends out of the air cooling sleeve 6, and the position of the air cooling sleeve 6 is different for different types of burners 5; the air cooling sleeve 6 is placed at the geometric center of the cross section of the primary air nozzle of the burner 5, and the air cooling sleeve 6 passes through the burner 5; the central processing unit 10 is connected to the burner 5 through the third control cable 8 The control end of the telescopic device 2 is connected to control the reciprocating operation of the telescopic device 2; the high-temperature resistant temperature measuring element 7 is connected to the central processing unit 10 via the data transmission line 9, the burner secondary air volume adjustment mechanism 13 and the burner secondary air swirl intensity adjustment mechanism 14 are both arranged on the burner 5, and the central processing unit 10 is connected to the burner secondary air volume adjustment mechanism 13 and the burner secondary air swirl intensity adjustment mechanism 14 through the first control cable 11 and the second control cable 12; the central processing unit 10 is connected to the control end of the coal mill 15, and is used to control the core operating parameters of the coal mill 15 such as the output of the coal mill 15, the inlet air volume or air door opening of the coal mill 15, the outlet temperature of the coal mill 15, and the separator speed.

[0039] As an embodiment of the present invention, the central processing unit 10 is connected to all the burners 5 in the same manner, and the ignition distance of the burner 5 is measured and optimized in real time online through the expert system in the central processing unit 10, thereby finally realizing online monitoring and real-time optimization adjustment of the hot ignition distance of the power plant boiler burner.

[0040] Embodiment 2

[0041] The present invention discloses an online monitoring and optimization method for the hot ignition distance of a power station boiler burner. The online monitoring and optimization method for the hot ignition distance of a power station boiler burner is implemented based on the online monitoring and optimization system for the hot ignition distance of a power station boiler burner. The online monitoring and optimization system for the hot ignition distance of a power station boiler burner includes a guide rail 1, a telescopic device 2, an instrument compressed air inlet regulating valve 3, an instrument compressed air pipe 4, a burner 5, an air-cooling sleeve 6, a high-temperature resistant temperature measuring element 7, a third control cable 8, a data transmission line 9, a central processing unit 10, a first control cable 11, a second control cable 12, a burner secondary air volume adjustment mechanism 13, a burner secondary air swirl intensity adjustment mechanism 14 and a coal mill 15; the online monitoring and optimization method for the hot ignition distance of a power station boiler burner includes the following steps:

[0042] Analysis of the ignition distance measurement principle: In modern combustion science, there is a clear definition of the hot ignition distance of the power station boiler burner 5. There is a clear flame front when the primary air-powder airflow ignites at the burner 5 nozzle. The distance from the flame front to the burner 5 nozzle is the hot ignition distance of the burner 5. The outside of the flame front is a high-temperature combustion zone, which is generally very high in temperature (>600°C), while the inside is a low-temperature zone (<500°C) with a lower temperature. There is an obvious temperature distinction between the two areas, and the dividing line is very narrow, which is the flame front. Based on this basic principle and law, the present invention adopts a progressive temperature measurement method to measure the temperature field distribution law of the primary air-powder airflow outside the burner 5 nozzle within a certain range along the airflow direction, so as to find the ignition front of the burner 5 and then obtain the ignition distance of the burner 5.

[0043] Since the overall temperature in the furnace is relatively high, the instrument compressed air inlet regulating valve 3, the instrument compressed air pipe 4 and the air-cooling sleeve 6 constitute the cooling system of the measuring device. The instrument compressed air also has certain anti-blocking and clearing functions in the air-cooling sleeve 6, ensuring that the high-temperature resistant temperature measuring element 7 runs unimpeded in the air-cooling sleeve 6, ensuring the safety, stability and accuracy of the measuring device in a high-temperature environment for a long time.

[0044] The material of the air-cooling sleeve 6 has the characteristics of high temperature resistance, wear resistance, high hardness and good ductility.

[0045] The high temperature resistant temperature measuring element 7 measures the temperature of the primary air-powder airflow within a predetermined interval through the guide rail 1 and the telescopic device 2. By testing the temperature distribution law at different depths, the central processor 10 processes and analyzes to obtain the ignition distance of the burner 5. The central processor 10 controls the telescopic stroke, rate and interval time of the telescopic device 2.

[0046] There are two main factors that affect the ignition distance of the burner 5: on the one hand, the operating state of the coal mill 15, and the corresponding control parameters of the coal mill 15 include the core operating parameters of the coal mill 15 such as the output of the coal mill 15, the inlet air volume or air door opening of the coal mill 15, the outlet temperature of the coal mill 15, and the separator speed; on the other hand, the combustion operating state, including the secondary air volume distribution characteristics inside and outside the burner 5 and the secondary air swirl intensity inside and outside the burner 5. The present invention optimizes and controls the burner secondary air volume adjustment mechanism 13 and the burner secondary air swirl intensity adjustment mechanism 14 in real time.

[0047] Based on the two aspects of the main factors affecting the ignition distance of the boiler burner 5, the expert system of the central processor 10 obtains the ignition distance of the burner 5 through testing, and determines whether it is within the optimal range. If so, the optimization adjustment system will not be activated temporarily; if not, the central processor 10 adjusts the burner secondary air volume adjustment mechanism 13 and the burner secondary air swirl intensity adjustment mechanism 14 in real time through the first control cable 11 and the second control cable 12. At the same time, the central processor 10 can directly optimize and control the operating parameters of the coal mill 15 in real time, so that the ignition distance of the burner 5 is finally within the optimal range.

[0048] As an embodiment of the present invention, the present invention can be used for a swirl burner or a direct current burner. The basic measurement principle and mechanism are the same, but the optimization adjustment control details are different.

[0049] The main optimization control strategy for adjusting the ignition distance of the swirl burner is: when the ignition distance is too long and needs to be reduced, the inner secondary air flow rate and its swirl intensity, the outer secondary air flow rate and its swirl intensity are increased, otherwise they are reduced. The adjustment range required for different burner 5 structures and coal qualities is different, and the specific adjustment characteristic curve needs to be determined based on actual debugging; when it is necessary to reduce the ignition distance, the coal mill 15 is mainly based on reducing the primary air-to-coal ratio of the coal mill and reducing the coal powder fineness, otherwise it is increased. The specific adjustment characteristic curve needs to be determined based on actual debugging.

[0050] The main optimization control strategy for adjusting the ignition distance of the DC burner is: since the DC burner has no internal and external secondary air, the corresponding ones are the peripheral air and auxiliary air. When the ignition distance is too long and needs to be reduced, the auxiliary air flow and the peripheral air flow corresponding to the burner 5 are reduced, and vice versa. The adjustment range required for different burner 5 structures, coal qualities, etc. is different, and the specific adjustment characteristic curve needs to be determined according to actual debugging; when it is necessary to reduce the ignition distance, for the coal mill 15, the main focus is on reducing the primary air-to-coal ratio of the coal mill and reducing the fineness of the coal powder, and vice versa, the specific adjustment characteristic curve needs to be determined according to actual debugging.

[0051] As an implementation mode of the present invention, the primary air powder temperature ranges from 0°C to 300°C, and the flow velocity ranges from 5m / s to 60m / s.

[0052] As an implementation mode of the present invention, the flow rate of the instrument compressed air is set according to factors such as the primary air powder temperature, flow rate, and the ignition temperature distance of the burner 5.

[0053] As an embodiment of the present invention, the present invention has two modes, automatic and manual. In the automatic mode, the ignition distance of each burner 5 can be tested and displayed in real time. In the manual mode, the ignition distance of each burner 5 can be tested manually.

[0054] As an embodiment of the present invention, the ignition distance test range of the burner 5 is 0-1000mm, the accuracy can be ±10mm, and the optimized control can achieve the ignition distance of the burner 5 to be stable within the range of 100mm-500mm.

[0055] The present invention is applicable to all types of boilers and burners 5 , and is not limited by the structure and distribution of the burners 5 .

[0056] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0057] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An online monitoring and optimization system for hot ignition distance of power station boiler burners, characterized in that: It comprises a high temperature resistant temperature measuring element (7), a telescopic device (2), a guide rail (1), a burner (5), a central processing unit (10), a burner secondary air volume adjustment mechanism (13), a burner secondary air swirl intensity adjustment mechanism (14) and a coal mill (15); The high temperature resistant temperature measuring element (7) is fixed on the telescopic device (2), and the telescopic device (2) is located on the guide rail (1), and the high temperature resistant temperature measuring element (7) passes through the burner (5); The central processing unit (10) is connected to a control end of the telescopic device (2), an output end of a high temperature resistant temperature measuring element (7), a control end of a burner secondary air volume regulating mechanism (13), a control end of a burner secondary air swirl intensity regulating mechanism (14), and a control end of a coal mill (15), wherein the outlet of the coal mill (15) is connected to the burner (5), and the burner secondary air volume regulating mechanism (13) and the burner secondary air swirl intensity regulating mechanism (14) are both arranged on the burner (5).

2. The power plant boiler burner hot ignition distance online monitoring and optimization system according to claim 1 is characterized in that: It also includes a measuring device cooling system, the measuring device cooling system including an instrument compressed air pipe (4) and an air cooling sleeve (6); An instrument compressed air inlet regulating valve (3) is installed on the instrument compressed air pipe (4), the instrument compressed air pipe (4) is connected to an air cooling sleeve (6), a high temperature resistant temperature measuring element (7) is placed in the air cooling sleeve (6), and a probe of the high temperature resistant temperature measuring element (7) extends out of the air cooling sleeve (6).

3. The on-line monitoring and optimization system for hot ignition distance of power plant boiler burners according to claim 1 is characterized in that: The high temperature resistant temperature measuring element (7) is connected to the central processing unit (10) via a data transmission line (9).

4. The power station boiler burner hot ignition distance online monitoring and optimization system according to claim 1 is characterized in that: The central processing unit (10) is connected to the burner secondary air volume adjustment mechanism (13) via a first control cable (11); the central processing unit (10) is connected to the burner secondary air swirl intensity adjustment mechanism (14) via a second control cable (12).

5. The on-line monitoring and optimization system for hot ignition distance of power plant boiler burners according to claim 1 is characterized in that: The central processing unit (10) is connected to the control end of the telescopic device (2) via a third control cable (8).

6. A method for online monitoring and optimization of hot ignition distance of a power plant boiler burner, characterized in that: The on-line monitoring and optimization system for hot ignition distance of a power plant boiler burner according to claim 1 comprises the following steps: The telescopic device (2) is controlled to move on the guide rail (1) so that the probe of the high temperature resistant temperature measuring element (7) moves toward the boiler side. During the movement, the temperature distribution of the primary air-powder airflow within a predetermined interval is measured by the probe of the high temperature resistant temperature measuring element (7). The ignition front of the burner (5) is obtained according to the temperature distribution law of the primary air-powder airflow within the predetermined interval, and the ignition distance of the burner (5) is determined according to the ignition front of the burner (5); It is determined whether the ignition distance of the burner (5) is within a preset distance range. When the ignition distance of the burner (5) is not within the preset distance range, the burner secondary air volume adjustment mechanism (13), the burner secondary air swirl intensity adjustment mechanism (14) and the coal mill (15) are controlled so that the ignition distance of the burner (5) is within the preset distance range.

7. The method for online monitoring and optimization of hot ignition distance of a power plant boiler burner according to claim 6, characterized in that: The burner is a swirl burner or a direct current burner.

8. The method for online monitoring and optimization of hot ignition distance of a power plant boiler burner according to claim 7, characterized in that: When the burner (5) is a swirl burner, when the ignition distance of the burner (5) exceeds the preset maximum ignition distance, the internal secondary air flow rate of the burner (5), the swirl intensity of the internal secondary air, the flow rate of the external secondary air and the swirl intensity of the external secondary air are increased, and / or the primary air-to-coal ratio and the coal powder fineness of the coal mill (15) are reduced; When the ignition distance of the burner (5) is less than the preset shortest ignition distance, the internal secondary air flow rate, the swirl intensity of the internal secondary air, the flow rate of the external secondary air and the swirl intensity of the external secondary air of the burner (5) are reduced, and / or the primary air-to-coal ratio and coal powder fineness of the coal mill (15) are increased.

9. The method for online monitoring and optimization of hot ignition distance of a power plant boiler burner according to claim 7, characterized in that: When the burner (5) is a direct current burner, when the ignition distance of the burner (5) exceeds the preset maximum ignition distance, the auxiliary sealing flow rate and the peripheral air flow rate of the burner (5) are reduced, and / or the primary air-to-coal ratio and the coal powder fineness of the coal mill (15) are reduced; When the burner (5) is a direct current burner, when the ignition distance of the burner (5) is less than the preset shortest ignition distance, the auxiliary sealing flow rate and the peripheral air flow rate of the burner (5) are increased, and / or the primary air-to-coal ratio and the coal powder fineness of the coal mill (15) are reduced.

10. The method for online monitoring and optimization of hot ignition distance of a power plant boiler burner according to claim 6, characterized in that: The ignition distance test range of the burner (5) is 0-1000mm; The optimized ignition distance of the burner (5) is 100 mm-500 mm.

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