A boiler combustion pressure pulsation control system

Abstract

The invention discloses a boiler combustion pressure pulsation control system, comprising an eddy current dynamic pressure sensor, a data acquisition instrument, a control unit and a combustion pressure pulsation monitoring center; the eddy current dynamic pressure sensor is inserted into the boiler furnace, the output end of the eddy current displacement sensor is connected to the input end of the data acquisition instrument, the output end of the data acquisition instrument is connected to the input end of the combustion pressure pulsation monitoring center, the output end of the combustion pressure pulsation monitoring center is connected to the input end of the control unit, the output end of the control unit is connected to the furnace oxygen control end, the coal powder fineness control end and the air distribution control end of the boiler, and the system can realize the control of the boiler combustion pressure pulsation.

Description

Technical Field

[0001] The invention belongs to the field of automatic control and relates to a boiler combustion pressure pulsation control system. Background Art

[0002] The pulverized coal combustion process in power plant boilers is a flow phenomenon with a violent exothermic chemical reaction. It includes flow, heat and mass transfer, combustion chemical reactions and their interactions. It is a complex physical and chemical process that occurs in a large spatial range, pulsates continuously, and has obvious three-dimensional characteristics. The combustion system of power plant boilers is an important link in thermal power production. The quality of the combustion state is not only affected by the interaction of many operating and control conditions, such as coal quality characteristics, changes in load conditions, and adjustments to air distribution, but also by many equipment factors. The control of the boiler's combustion system is very complex. It is necessary to ensure that the boiler always operates within the stable combustion working range. Once the combustion instability occurs in the boiler, it is easy to cause problems such as coking and slagging, flameout, and increased CO emissions. In severe cases, there may be malignant accidents such as boiler explosions. Accurate monitoring of the boiler's combustion state is the primary task of boiler combustion control. Existing boiler combustion monitoring mainly judges the combustion stability state in the boiler by monitoring the changes in the combustion flame. Combustion pressure pulsation is another important parameter characterizing combustion instability. Accurately measuring the combustion pressure pulsation of high-temperature flue gas in a boiler can improve the accuracy of boiler combustion state diagnosis and enhance boiler operation safety. However, the prior art does not disclose a method for accurately controlling boiler combustion pressure pulsation. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a boiler combustion pressure pulsation control system, which can realize the control of boiler combustion pressure pulsation.

[0004] To achieve the above-mentioned object, the boiler combustion pressure pulsation control system of the present invention comprises an eddy current dynamic pressure sensor, a data acquisition instrument, a control unit and a combustion pressure pulsation monitoring center;

[0005] The eddy current dynamic pressure sensor is inserted into the boiler furnace, the output end of the eddy current displacement sensor is connected to the input end of the data acquisition instrument, the output end of the data acquisition instrument is connected to the input end of the combustion pressure pulsation monitoring center, the output end of the combustion pressure pulsation monitoring center is connected to the input end of the control unit, and the output end of the control unit is connected to the boiler's furnace oxygen control end, coal powder fineness control end and air distribution control end.

[0006] The eddy current dynamic pressure sensor comprises an eddy current displacement sensor, an upper sealing shell, a vacuum outer wall, a lower sealing shell, a sealing film and a mounting nut;

[0007] The upper sealed shell, the vacuum outer wall and the lower sealed shell are arranged in sequence from top to bottom, the upper sealed shell is provided with a through hole, the vacuum outer wall is provided with a vacuum insulation cavity, and the lower sealed shell is provided with a pressure-inducing hole, wherein the through hole is connected with the vacuum insulation cavity;

[0008] The probe of the eddy current displacement sensor is inserted into the through hole from top to bottom, a heat insulation material layer is arranged between the lower sealed shell and the vacuum outer wall, a metal sensing diaphragm is arranged in the middle of the heat insulation material layer, the vacuum heat insulation cavity and the pressure induction hole are separated by the metal sensing diaphragm, the vacuum outer wall and the upper sealed shell are connected by a mounting nut, wherein the mounting nut is sleeved on the vacuum outer wall and the outer wall of the upper sealed shell; a sealing film is arranged at the bottom of the lower sealed shell, wherein the lower end of the pressure induction hole is closed by the sealing film, and a plurality of air bleed filter holes are arranged on the sealing film, each air bleed filter hole is directly opposite to the pressure induction hole, and each air bleed filter hole is evenly distributed;

[0009] The lower sealing shell is inserted into the boiler furnace.

[0010] The probe of the eddy current displacement sensor has a diameter of 5 mm and a length of 20 mm;

[0011] The outer diameter of the upper sealing shell is 12mm, the inner diameter is 5mm, and the height is 18mm;

[0012] The outer diameter of the vacuum outer wall is 12mm, the inner diameter is 5mm, and the height is 2mm;

[0013] The outer diameter of the lower sealing shell is 10mm, the inner diameter is 6mm, and the height is 6mm;

[0014] The outer diameter of the metal sensing diaphragm is 8 mm and the thickness is 1 mm; the aperture of the air filter hole is 0.5 mm.

[0015] The axes of the eddy current displacement sensor, the upper sealed shell, the vacuum outer wall and the lower sealed shell coincide with each other.

[0016] The upper sealed shell is connected to the vacuum outer wall by diffusion welding.

[0017] The vacuum outer wall is connected to the lower sealed shell by diffusion welding.

[0018] The present invention has the following beneficial effects:

[0019] The boiler combustion pressure pulsation control system described in the present invention adopts the non-contact electromagnetic induction principle during specific operation, and uses an eddy current displacement sensor to measure the deformation displacement of the metal sensing diaphragm. According to the proportional relationship between the deformation displacement and the pressure, the real-time pressure of the gas in the boiler furnace is directly obtained, and a vacuum insulation cavity and an insulation material layer are used to prevent the heat of the gas in the furnace from being transferred outward, thereby protecting the eddy current displacement sensor from working normally under high-temperature measured working fluids. In actual operation, the eddy current dynamic pressure sensor can be installed on the furnace wall of the boiler to directly measure the pressure pulsation of the high-temperature flue gas in the furnace, and the combustion stability state of the boiler can be diagnosed and controlled according to the pressure pulsation frequency and amplitude, thereby improving the accuracy of the boiler's combustion state monitoring, diagnosis and control, which is beneficial to improving the safety of boiler operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of an eddy current dynamic pressure sensor.

[0022] Among them, 1 is an eddy current dynamic pressure sensor, 2 is a data acquisition instrument, 3 is a combustion pressure pulsation monitoring center, 4 is a control unit, 5 is a boiler, 6 is an eddy current displacement sensor, 7 is an upper sealed shell, 8 is a vacuum outer wall, 9 is a thermal insulation material layer, 10 is a lower sealed shell, 11 is a pressure inlet hole, 12 is a sealing film, 13 is a metal sensing diaphragm, 14 is a vacuum insulation cavity, and 15 is a mounting nut. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and is not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in 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 should fall within the scope of protection of the present invention.

[0024] The accompanying drawings show schematic diagrams of structures according to embodiments disclosed in the present invention. 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.

[0025] refer to Figure 1 and Figure 2 The boiler combustion pressure pulsation control system of the present invention comprises an eddy current dynamic pressure sensor 1, a data acquisition instrument 2, a control unit 4 and a combustion pressure pulsation monitoring center 3;

[0026] The eddy current dynamic pressure sensor 1 comprises an eddy current displacement sensor 6, an upper sealing shell 7, a vacuum outer wall 8, a lower sealing shell 10, a sealing membrane 12 and a mounting nut 15;

[0027] The upper sealed shell 7, the vacuum outer wall 8 and the lower sealed shell 10 are distributed in sequence from top to bottom. The upper sealed shell 7 is provided with a through hole, the vacuum outer wall 8 is provided with a vacuum insulation cavity 14, and the lower sealed shell 10 is provided with a pressure-inducing hole 11, wherein the through hole is connected with the vacuum insulation cavity 14.

[0028] The probe of the eddy current displacement sensor 6 is inserted into the through hole from top to bottom, a heat insulation material layer 9 is arranged between the lower sealed shell 10 and the vacuum outer wall 8, a metal sensing diaphragm 13 is arranged in the middle of the heat insulation material layer 9, the vacuum insulation cavity 14 and the pressure-inducing hole 11 are separated by the metal sensing diaphragm 13, the vacuum outer wall 8 and the upper sealed shell 7 are connected by a mounting nut 15, wherein the mounting nut 15 is sleeved on the outer wall of the vacuum outer wall 8 and the upper sealed shell 7; a sealing film 12 is arranged at the bottom of the lower sealed shell 10, wherein the lower end of the pressure-inducing hole 11 is closed by the sealing film 12, and a plurality of air bleed filter holes are arranged on the sealing film 12, each air bleed filter hole is opposite to the pressure-inducing hole 11, and each air bleed filter hole is evenly distributed.

[0029] The lower sealed shell 10 is inserted into the furnace of the boiler 5, the output end of the eddy current displacement sensor 6 is connected to the input end of the data acquisition instrument 2, the output end of the data acquisition instrument 2 is connected to the input end of the combustion pressure pulsation monitoring center 3, the output end of the combustion pressure pulsation monitoring center 3 is connected to the input end of the control unit 4, and the output end of the control unit 4 is connected to the furnace oxygen control end, the coal powder fineness control end and the air distribution control end of the boiler 5.

[0030] The probe of the eddy current displacement sensor 6 has a diameter of 5 mm and a length of 20 mm;

[0031] The upper sealing housing 7 has an outer diameter of 12 mm, an inner diameter of 5 mm and a height of 18 mm;

[0032] The outer diameter of the vacuum outer wall 8 is 12 mm, the inner diameter is 5 mm, and the height is 2 mm;

[0033] The lower sealing housing 10 has an outer diameter of 10 mm, an inner diameter of 6 mm, and a height of 6 mm;

[0034] The outer diameter of the metal sensing diaphragm 13 is 8 mm, and the thickness is 1 mm; the aperture of the air filter hole is 0.5 mm.

[0035] The axes of the eddy current displacement sensor 6, the upper sealed shell 7, the vacuum outer wall 8 and the lower sealed shell 10 coincide with each other; the upper sealed shell 7 is connected to the vacuum outer wall 8 by diffusion welding, and the vacuum outer wall 8 is connected to the lower sealed shell 10 by diffusion welding.

[0036] The specific working process of the present invention is:

[0037] When the boiler combustion pressure pulsation control system is working, the gas in the furnace enters the pressure induction hole 11 after being filtered through the air bleed filter hole. The metal sensing diaphragm 13 is deformed under the action of the gas pressure in the furnace. The deformation change is measured by the eddy current displacement sensor 6, and it is converted into a voltage signal and then output. According to the calibration curve of the sensor, that is, the curve relationship between voltage and pressure, the pressure of the gas in the furnace is obtained in real time. During the measurement process, the vacuum insulation cavity 14 and the insulation material layer 9 are used to jointly insulate the eddy current displacement sensor 6 from being burned by the high-temperature working medium. The data acquisition instrument 2 collects the voltage signal output by the eddy current dynamic pressure sensor 1 in real time according to the sampling frequency controlled by the combustion pressure pulsation monitoring center 3, and outputs the voltage signal to the combustion pressure pulsation monitoring center 3. The combustion pressure pulsation monitoring center 3 converts the voltage signal output by the data acquisition instrument 2 into real-time pressure. According to the real-time pressure amplitude and frequency, the oxygen content, coal powder fineness and air distribution mode of the furnace of the boiler 5 are controlled through the control unit 4 to ensure the stable combustion of the boiler 5 and always control the combustion pressure pulsation in a safe and stable area.

[0038] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A boiler combustion pressure pulsation control system, characterized in that: It comprises an eddy current dynamic pressure sensor (1), a data acquisition instrument (2), a control unit (4) and a combustion pressure pulsation monitoring center (3); An eddy current dynamic pressure sensor (1) is inserted into a furnace of a boiler (5); an output end of an eddy current displacement sensor (6) is connected to an input end of a data acquisition instrument (2); an output end of the data acquisition instrument (2) is connected to an input end of a combustion pressure pulsation monitoring center (3); an output end of the combustion pressure pulsation monitoring center (3) is connected to an input end of a control unit (4); an output end of the control unit (4) is connected to a furnace oxygen control end, a coal powder fineness control end, and an air distribution control end of the boiler (5); The eddy current dynamic pressure sensor (1) comprises an eddy current displacement sensor (6), an upper sealing shell (7), a vacuum outer wall (8), a lower sealing shell (10), a sealing film (12) and a mounting nut (15); The upper sealed shell (7), the vacuum outer wall (8) and the lower sealed shell (10) are arranged in sequence from top to bottom; the upper sealed shell (7) is provided with a through hole, the vacuum outer wall (8) is provided with a vacuum insulation cavity (14), and the lower sealed shell (10) is provided with a pressure-inducing hole (11), wherein the through hole is in communication with the vacuum insulation cavity (14); The probe of the eddy current displacement sensor (6) is inserted into the through hole from top to bottom, a heat insulation material layer (9) is arranged between the lower sealed shell (10) and the vacuum outer wall (8), a metal sensing diaphragm (13) is arranged in the middle of the heat insulation material layer (9), the vacuum heat insulation cavity (14) and the pressure induction hole (11) are separated by the metal sensing diaphragm (13), the vacuum outer wall (8) and the upper sealed shell (7) are connected by a mounting nut (15), wherein the mounting nut (15) is sleeved on the vacuum outer wall (8) and the outer wall of the upper sealed shell (7); a sealing film (12) is arranged at the bottom of the lower sealed shell (10), wherein the lower end of the pressure induction hole (11) is closed by the sealing film (12), and a plurality of air bleed filter holes are arranged on the sealing film (12), each of which is directly opposite to the pressure induction hole (11), and each of which is evenly distributed; The lower sealed housing (10) is inserted into the furnace of the boiler (5); The vacuum outer wall (8) is connected to the lower sealed shell (10) by diffusion welding.

2. The boiler combustion pressure pulsation control system according to claim 1, characterized in that: The probe of the eddy current displacement sensor (6) has a diameter of 5 mm and a length of 20 mm; The upper sealing housing (7) has an outer diameter of 12 mm, an inner diameter of 5 mm and a height of 18 mm; The outer diameter of the vacuum outer wall (8) is 12 mm, the inner diameter is 5 mm, and the height is 2 mm; The lower sealing housing (10) has an outer diameter of 10 mm, an inner diameter of 6 mm and a height of 6 mm; The outer diameter of the metal sensing diaphragm (13) is 8 mm and the thickness is 1 mm; the aperture of the air bleed filter hole is 0.5 mm.

3. The boiler combustion pressure pulsation control system according to claim 2, characterized in that: The axes of the eddy current displacement sensor (6), the upper sealed housing (7), the vacuum outer wall (8) and the lower sealed housing (10) coincide with each other.

4. The boiler combustion pressure pulsation control system according to claim 3, characterized in that: The upper sealed shell (7) is connected to the vacuum outer wall (8) by diffusion welding.

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