Measuring method, leveling method and device for primary air speed of pulverized coal pipeline at outlet of coal mill

Abstract

The invention provides a coal mill outlet pulverized coal pipeline primary wind speed measuring method, a leveling method and a device, and the wind speed measuring method comprises the steps: selecting two measurement sections on each pulverized coal pipeline at the outlet of a coal mill, and respectively installing pressure transmitters on the two measurement sections to measure the static pressure values of the two measurement sections; calculating the pipeline resistance according to the static pressure values of the two measurement sections; establishing a relational expression between the pipeline resistance and the fluid flow velocity; and obtaining the primary air speed of each pulverized coal pipeline according to the relational expression. The two measurement sections are selected on the pulverized coal pipeline, the static pressure difference of the pulverized coal pipeline is measured, the wind speed is calculated based on the relational expression of the pipeline resistance and the fluid flow speed, complex measurement equipment and operation are avoided, and implementation is easy. In addition, based on the basic principle of fluid mechanics, correction can be conducted by combining actual working conditions of the pulverized coal pipeline, and the measurement result is accurate and reliable.

Description

Technical Field

[0001] The invention relates to the technical field of wind speed measurement and leveling, and in particular to a primary wind speed measurement method, a leveling method and a device for a coal mill outlet coal powder pipeline. Background Art

[0002] During the operation of power plant boilers, coal mills are the most commonly used pulverizing equipment for boilers. In order to ensure stable combustion in the boiler and avoid combustion deviation, the wind speed of the coal pulverizer outlet pipeline is required to be as close as possible, and the relative deviation of the wind speed of each coal pulverizer pipeline cannot exceed ±5%. However, due to the differences in the length and resistance of each coal pulverizer outlet pipeline, the wind speed of each coal pulverizer pipeline varies greatly.

[0003] In view of the above problems, a relatively effective preventive measure is to install an adjustable shrinkage hole on the coal pulverizer outlet coal pulverizer pipe, and then conduct a wind speed leveling test to ensure that the relative deviation of the wind speed of each coal pulverizer pipe does not exceed ±5%. However, in this process, it is necessary to accurately measure the wind speed of each coal pulverizer pipe. When measuring the wind speed of the coal pulverizer pipe, the existing technology still has the defects of insufficient accuracy or too complicated implementation. Summary of the invention

[0004] In view of this, the present invention provides a method for measuring the primary wind speed of a pulverized coal pipeline at a coal mill outlet, a leveling method and a device to solve at least one of the above-mentioned problems.

[0005] In order to achieve the above object, the present invention adopts the following scheme:

[0006] According to a first aspect of the present invention, there is provided a method for measuring the primary wind speed of a pulverized coal pipeline at a coal mill outlet, the method comprising: selecting two measuring sections on each pulverized coal pipeline at the coal mill outlet, and installing pressure transmitters on the two measuring sections respectively to measure the static pressure values ​​of the two measuring sections; calculating the pipeline resistance according to the static pressure values ​​of the two measuring sections; establishing a relationship between the pipeline resistance and the fluid flow rate; and obtaining the primary wind speed of each pulverized coal pipeline according to the relationship.

[0007] As an implementation of the present invention, in the above method, the pipeline length and local resistance coefficient between two measurement sections selected on each coal powder pipeline remain unchanged during measurement, and there is no component between the two measurement sections that will change the resistance coefficient.

[0008] As an implementation of the present invention, in the above method, the length of the pipeline between two measurement sections selected on the same pulverized coal pipeline is more than 5 meters.

[0009] As an implementation of the present invention, the method for calculating the pipeline resistance according to the static pressure values ​​of the two measurement sections includes:

[0010] According to the static pressure values ​​of the two measurement sections, the pipeline resistance is calculated using the following formula:

[0011] Δp=p1-p2;

[0012] In the above formula, Δp is the pipeline resistance; p1 is the pipeline static pressure value at the first measuring section; p2 is the pipeline static pressure value at the second section.

[0013] As an implementation of the present invention, the relationship between the pipeline resistance and the fluid flow rate established in the above method is:

[0014]

[0015] In the above formula, C is the total resistance coefficient of the pulverized coal pipeline, μ is the concentration of pulverized gas, ρ is the fluid density, and ω is the fluid flow rate.

[0016] As an implementation of the present invention, in the above method, obtaining the primary wind speed of each pulverized coal pipeline according to the relationship includes:

[0017] The fluid velocity of each pulverized coal pipeline is obtained using the following formula and is used as the corrected primary wind speed of the pipeline:

[0018]

[0019] The primary wind speed in the pulverized coal pipeline is measured by using a pitot tube and a micromanometer, and the primary wind speed to be corrected is calibrated by using the measurement result to obtain the corrected primary wind speed.

[0020] According to a second aspect of the present invention, a method for leveling the primary wind speed of a pulverized coal pipeline at a coal mill outlet is provided, the method comprising: obtaining the primary wind speed of each pulverized coal pipeline by the method as described above; calculating the relative deviation of the primary wind speed of each pulverized coal pipeline based on the obtained primary wind speed of each pulverized coal pipeline; and adjusting the adjustable shrinkage holes on the pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

[0021] As an implementation of the present invention, the above-mentioned adjusting the adjustable shrinkage holes on the pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5% includes: in the cold environment of the unit, adjusting the adjustable shrinkage holes on each pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%; in the hot environment of the unit, adjusting the adjustable shrinkage holes on each pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

[0022] According to a third aspect of the present invention, there is provided a device for measuring the primary wind speed of a pulverized coal pipeline at a pulverizer outlet, the device comprising: a static pressure value measuring unit, for selecting two measuring sections on each pulverized coal pipeline at the pulverizer outlet, and installing pressure transmitters on the two measuring sections, respectively, to measure the static pressure values ​​of the two measuring sections; a pipeline resistance calculating unit, for calculating the pipeline resistance according to the static pressure values ​​of the two measuring sections; a relationship establishing unit, for establishing a relationship between the pipeline resistance and the fluid flow rate; and a wind speed obtaining unit, for obtaining the primary wind speed of each pulverized coal pipeline according to the relationship.

[0023] As an implementation of the present invention, the pipeline length and local resistance coefficient between two measurement sections selected on each pulverized coal pipeline remain unchanged during measurement, and there is no component between the two measurement sections that will change the resistance coefficient.

[0024] As an implementation of the present invention, the length of the pipeline between two measurement sections selected on the same pulverized coal pipeline is more than 5 meters.

[0025] As an implementation of the present invention, the pipeline resistance calculation unit calculates the pipeline resistance according to the static pressure values ​​of the two measurement sections, including:

[0026] According to the static pressure values ​​of the two measurement sections, the pipeline resistance is calculated using the following formula:

[0027] Δp=p1-p2;

[0028] In the above formula, Δp is the pipeline resistance; p1 is the pipeline static pressure value at the first measuring section; p2 is the pipeline static pressure value at the second section.

[0029] As an implementation of the present invention, the established relationship between the pipeline resistance and the fluid flow rate is:

[0030]

[0031] In the above formula, C is the total resistance coefficient of the pulverized coal pipeline, μ is the concentration of pulverized gas, ρ is the fluid density, and ω is the fluid flow rate.

[0032] As an implementation of the present invention, the wind speed acquisition unit obtains the primary wind speed of each pulverized coal pipeline according to the relationship, including:

[0033] The fluid velocity of each pulverized coal pipeline is obtained using the following formula and is used as the corrected primary wind speed of the pipeline:

[0034]

[0035] The primary wind speed in the pulverized coal pipeline is measured by using a pitot tube and a micromanometer, and the primary wind speed to be corrected is calibrated by using the measurement result to obtain the corrected primary wind speed.

[0036] According to a fourth aspect of the present invention, there is provided a primary wind speed leveling device for a pulverized coal pipeline at a pulverizer outlet, the device comprising: a primary wind speed measuring device as described above; a relative deviation calculation unit for calculating the relative deviation of the primary wind speed of each pulverized coal pipeline based on the primary wind speed measured by the primary wind speed measuring device; and a deviation adjustment unit for adjusting the adjustable shrinkage holes on the pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

[0037] As an implementation of the present invention, the above-mentioned deviation adjustment unit is specifically used to, in a cold environment of the unit, adjust the adjustable shrinkage holes on each pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%; in a hot environment of the unit, adjust the adjustable shrinkage holes on each pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

[0038] According to a fifth aspect of the present invention, there is provided an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0039] According to a sixth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0040] According to a seventh aspect of the present invention, there is provided a computer program product, comprising a computer program / instructions, which implement the steps of the above method when executed by a processor.

[0041] It can be seen from the above technical scheme that the method for measuring the primary wind speed of the coal powder pipeline at the outlet of the coal mill, the method for leveling and the device provided by the present invention, by selecting two measuring sections on the coal powder pipeline, measuring the static pressure difference, and calculating the wind speed based on the relationship between the pipeline resistance and the fluid flow rate, avoids complicated measuring equipment and operations, and is easy to implement. In addition, the present invention is based on the basic principles of fluid mechanics, and can be corrected in combination with the actual working conditions of the coal powder pipeline, and the measurement results are accurate and reliable. Moreover, since the measuring device can be directly installed on the coal powder pipeline and collect data in real time, online monitoring of the wind speed can be achieved, which is convenient for timely discovery and adjustment of wind speed deviations, and ensures stable boiler combustion. Finally, the wind speed of each pipeline is accurately measured by the present invention, and the adjustable shrinkage hole is adjusted according to the relative deviation of the wind speed, so that the wind speed of each pipeline can be effectively leveled, so that its relative deviation is less than ±5%, thereby improving the combustion efficiency of the boiler and reducing the combustion deviation phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0043] Figure 1 It is a flow chart of a method for measuring primary wind speed of a coal pulverizer outlet coal pulverizer pipeline provided in an embodiment of the present application;

[0044] Figure 2 This is a schematic diagram of the layout of a coal powder pipeline at the outlet of a four-corner tangential boiler coal mill provided by an embodiment of the present invention;

[0045] Figure 3 It is a schematic diagram of static pressure opening on the wall of a pulverized coal pipeline provided in an embodiment of the present application;

[0046] Figure 4 It is a schematic flow chart of a method for adjusting the primary wind speed of a coal mill outlet pulverized coal pipeline provided in an embodiment of the present application;

[0047] Figure 5 It is a structural schematic diagram of a primary wind speed measuring device for a coal mill outlet coal powder pipeline provided in an embodiment of the present application;

[0048] Figure 6 It is a structural schematic diagram of a primary wind speed leveling device for a pulverized coal pipeline at a coal mill outlet provided in an embodiment of the present application;

[0049] Figure 7 It is a schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0051] The fluid in the coal pulverizer outlet coal pulverizer pipeline is pure air or air-powder mixture, which is a non-ideal fluid. When the fluid flows in the coal pulverizer pipeline, it will be subject to friction resistance and local resistance. Therefore, the resistance of a certain section of the coal pulverizer pipeline is measured, and the fluid flow rate in the coal pulverizer pipeline (i.e., primary wind speed) can be calculated based on the relationship between the resistance and the fluid flow rate in the coal pulverizer pipeline.

[0052] like Figure 1The figure is a flow chart of a method for measuring the primary wind speed of a coal mill outlet coal pulverized pipe provided in an embodiment of the present application. The method comprises the following steps:

[0053] Step S101: Select two measuring sections on each pulverized coal pipeline at the outlet of the coal mill, and install pressure transmitters on the two measuring sections respectively to measure the static pressure values ​​of the two measuring sections.

[0054] The key to this step is to select the appropriate measurement section and install the pressure transmitter on each pulverized coal pipeline.

[0055] Selection of measuring section: In order to ensure the measurement accuracy, the measuring section should be selected at a position where the straight pipe sections before and after the pulverized coal pipeline are longer and the parameters such as the length of the pipeline and the local resistance coefficient between the two measuring sections remain unchanged. There should be no adjustable shrinkage holes or other components between the two measuring sections that may cause changes in the friction resistance coefficient or the local resistance coefficient. Preferably, the distance between the two measuring sections is more than 5 meters. More preferably, the length of the pulverized coal pipeline and the number of elbows between the two static pressure measurement sections of each pulverized coal pipeline are kept consistent, so that the friction resistance coefficient and the local resistance coefficient between the two static pressure measurement sections of each pulverized coal pipeline can be consistent, which can simplify the calculation.

[0056] like Figure 2 The figure shows a schematic diagram of the layout of the coal pulverized pipe at the outlet of a four-corner tangential boiler coal mill provided by an embodiment of the present invention. Figure 2 It can be seen that there are four pulverized coal pipelines A1, A2, A3 and A4, and two measurement sections are selected on each pulverized coal pipeline, for example, sections A11 and A12 are selected on pipeline A1, and sections A21 and A22 are selected on pipeline A2. Figure 2 The front and rear straight pipe sections of the two cross sections of each pipeline are relatively long, and each has only one elbow, which meets the requirements of this application.

[0057] Installation of pressure transmitter: Drill a hole (diameter Φ4mm, smooth inner wall without burrs) on the selected measuring section, and then install the pressure transmitter. For details, please refer to Figure 3 As shown. Preferably, in this embodiment, each measuring section is arranged with no less than 2 measuring points along the circumference, and then each point is measured separately and the average value is taken to ensure the accuracy of the static pressure measurement. More preferably, the static pressure opening is connected to compressed air, and back-blowing is performed regularly to prevent clogging, and the pressure transmitter transmits the measured static pressure value signal to the static pressure value measurement unit.

[0058] Step S102: Calculating pipeline resistance according to the static pressure values ​​of the two measurement sections.

[0059] From the Bernoulli equation, we know that for the non-ideal fluid in the same pulverized coal pipeline, the mechanical energy between any two points satisfies the following formula (1):

[0060]

[0061] In the above formula:

[0062] p1, the static pressure of the pipe at the measuring section 1, Pa;

[0063] ρ1, density of fluid at measuring section 1, kg / m 3 ;

[0064] ω1, fluid velocity at measuring section 1, m / s;

[0065] g, acceleration due to gravity, 9.8 m / s 2 ;

[0066] h1, height of measuring section 1, m;

[0067] p2, the static pressure of the pipe at the measuring section 2, Pa;

[0068] ρ2, density of fluid at section 2, kg / m 3 ;

[0069] ω2, fluid velocity at measuring section 2, m / s;

[0070] h2, height of measuring section 2, m;

[0071] Δp, pulverized coal pipeline resistance, Pa.

[0072] Since the inner diameter of the pulverized coal pipeline between the measurement section 1 and the measurement section 2 is the same, the fluid temperature, fluid absolute pressure and fluid absolute height do not change much, so the changes in fluid temperature, absolute pressure and absolute height can be ignored, and the above formula (1) can be changed to:

[0073] Δp=p1-p2 (2)

[0074] In the above formula:

[0075] Δp, pulverized coal pipeline resistance, Pa;

[0076] p1, the static pressure of the pipe at section 1, Pa, obtained by collecting real-time data;

[0077] p2, the pipe static pressure at measurement section 2, Pa, is obtained by collecting real-time data.

[0078] It can be seen that the resistance of the pulverized coal pipeline can be obtained by only knowing the pipeline static pressure at two measuring sections of each pulverized coal pipeline and calculating the difference between the two. The pipeline static pressure can be measured by installing a pressure transmitter on the measuring section in the above step S101.

[0079] Step S103: establishing a relationship between the pipeline resistance and the fluid flow rate.

[0080] The fluid in the coal powder pipeline at the coal mill outlet is pure air or air-powder mixture, which is a non-ideal fluid. When the fluid flows in the coal powder pipeline, it will be subject to friction resistance and local resistance.

[0081] The calculation formula is:

[0082] (1) Frictional resistance

[0083]

[0084] p m , friction resistance, Pa;

[0085] μ, powdery gas concentration, kg / kg, requires real-time collection of coal volume at coal mill inlet, coal mill inlet air volume, and coal mill sealing air volume, and then the powdery gas concentration is calculated from the above data. The calculation method can refer to DL / T467-2019 "Performance Test of Coal Mill and Pulverizing System in Power Plant";

[0086] λ0, friction coefficient of pure air flow, usually 0.015 for pulverized coal pipeline;

[0087] L, calculated length of pipeline friction resistance, m, can be obtained by actual measurement;

[0088] D, equivalent diameter of the pipeline, m, can be obtained by actual measurement;

[0089] ρ, fluid density, kg / m 3 , it is necessary to collect the coal powder pipeline fluid temperature, fluid pressure, ambient atmospheric pressure, and air density under standard conditions in real time, and then calculate the fluid density from the above data. The calculation method can refer to DL / T 467-2019 "Performance Test of Power Plant Coal Mill and Pulverizing System";

[0090] ω, fluid flow rate, m / s.

[0091] (2) Local resistance

[0092]

[0093] P j , local resistance, Pa;

[0094] ζ0, the local resistance coefficient when pure air flows, is related to the form and bending radius of the pulverized coal pipeline bend. If the pulverized coal pipeline is determined, ζ0 is a constant value and can be calculated by referring to DL / T 5145-2012 "Technical Regulations for Design and Calculation of Pulverizing Systems in Thermal Power Plants".

[0095] (3) Total pipeline resistance

[0096]

[0097] make but

[0098]

[0099] Where C is a fixed coefficient related to the pulverized coal pipeline, called the total resistance coefficient of the pulverized coal pipeline. If the pulverized coal pipeline is determined, C is a constant value, which can be calculated by referring to DL / T 5145-2012 "Technical Regulations for Design and Calculation of Pulverized Coal Systems in Thermal Power Plants".

[0100] Step S104: obtaining the primary wind speed of each pulverized coal pipeline according to the relationship.

[0101] Combining the above formulas (2) and (6), we can obtain the following formula (7):

[0102]

[0103] Where ω is the fluid flow rate, which is also the primary wind speed to be corrected in this application.

[0104] Next, in this embodiment, the primary wind speed in the pulverized coal pipeline can be measured using a pitot tube and a micromanometer, and the measurement results are used to calibrate the primary wind speed to be corrected to obtain the corrected primary wind speed, which is specifically shown in the following formula (8):

[0105]

[0106] Where ω' is the corrected primary wind speed, and k is the primary wind speed correction coefficient.

[0107] It can be seen from the above technical scheme that the method for measuring the primary wind speed of the coal powder pipeline at the outlet of the coal mill provided by the present invention selects two measurement sections on the coal powder pipeline, measures the static pressure difference, and calculates the wind speed based on the relationship between the pipeline resistance and the fluid flow rate, thereby avoiding complex measurement equipment and operations and being easy to implement. In addition, the present invention is based on the basic principles of fluid mechanics and can be corrected in combination with the actual working conditions of the coal powder pipeline, so that the measurement results are accurate and reliable. Moreover, since the measuring device can be directly installed on the coal powder pipeline and collect data in real time, online monitoring of the wind speed can be achieved, which is convenient for timely detection and adjustment of wind speed deviations and ensures stable boiler combustion.

[0108] like Figure 4 The figure shows a flow chart of a method for adjusting the primary wind speed of a coal mill outlet coal pulverized pipeline provided in an embodiment of the present application. The method comprises the following steps:

[0109] Step S401: Select two measuring sections on each pulverized coal pipeline at the outlet of the coal mill, and install pressure transmitters on the two measuring sections respectively to measure the static pressure values ​​of the two measuring sections.

[0110] Step S402: Calculate pipeline resistance according to the static pressure values ​​of the two measurement sections.

[0111] Step S403: establishing a relationship between the pipeline resistance and the fluid flow rate.

[0112] Step S404: Obtain the primary wind speed of each pulverized coal pipeline according to the relationship.

[0113] The above steps S401 to S404 can refer to the description of the above steps S101 to S104, which will not be further described here.

[0114] Step S405: Calculate the relative deviation of the primary wind speed of each pulverized coal pipeline according to the obtained primary wind speed of each pulverized coal pipeline.

[0115] A pipeline that is divided into several pipelines at a certain point and then merges into one pipeline somewhere downstream is called a parallel pipeline. The outlet pulverized coal pipeline of the power plant pulverizer is a typical parallel pipeline.

[0116] The inner diameters of the pulverized coal pipes at the outlet of the coal mill are equal, and the parameters such as the fluid temperature, fluid absolute pressure, inner wall absolute roughness and powder-containing gas concentration in the pulverized coal pipes are basically the same. It can be considered that the above parameters are equal. Then the primary wind speed and the relative deviation of the primary wind speed of each pulverized coal pipe at the outlet of the coal mill are:

[0117]

[0118] …

[0119]

[0120] …

[0121]

[0122] In the above formula:

[0123] ω' A1 , A1 pulverized coal pipeline corrected primary air velocity, m / s;

[0124] k A1 , A1 pulverized coal pipeline primary velocity correction coefficient, obtained through calibration test;

[0125] μ, powdery gas concentration, kg / kg, requires real-time collection of coal flow at coal mill inlet, coal mill inlet air volume, and coal mill sealing air volume. The powdery gas concentration can be calculated from the above data. The calculation method can refer to DL / T467-2019 "Performance Test of Coal Mill and Pulverizing System in Power Plant";

[0126] ρ, fluid density, kg / m 3 , it is necessary to collect the fluid temperature, fluid pressure, ambient atmospheric pressure, and air density under standard conditions of the pulverized coal pipeline in real time, and calculate the fluid density from the above data. The calculation method can refer to DL / T 467-2019 "Performance Test of Power Plant Coal Mill and Pulverizing System";

[0127] p A11 , static pressure of section A11 of pulverized coal pipeline A1, Pa, obtained by collecting real-time data;

[0128] p A12 , static pressure of section A12 of A1 pulverized coal pipeline, Pa, obtained by collecting real-time data;

[0129] C A1 , A1 total resistance coefficient of pulverized coal pipeline, the fixed value related to pulverized coal pipeline can be calculated by referring to DL / T 5145-2012 "Technical Regulations for Design and Calculation of Pulverized Coal System in Thermal Power Plant";

[0130] ω' A2 , A2 coal powder pipeline corrected primary air velocity, m / s;

[0131] k A2 , A2 pulverized coal pipeline primary velocity correction coefficient, obtained through calibration test;

[0132] p A21 , static pressure of section A21 of A2 pulverized coal pipeline, Pa, obtained by collecting real-time data;

[0133] p A22 , static pressure of section A22 of pulverized coal pipeline A2, Pa, obtained by collecting real-time data;

[0134] C A2 , A2 total resistance coefficient of pulverized coal pipeline, the fixed value related to pulverized coal pipeline can be calculated by referring to DL / T 5145-2012 "Technical Regulations for Design and Calculation of Pulverized Coal System in Thermal Power Plant";

[0135] ω' An , An coal powder pipeline corrected primary wind speed, m / s;

[0136] k An , is the primary wind speed correction coefficient of the pulverized coal pipeline, obtained through calibration test;

[0137] p An1 , static pressure of An1 section of pulverized coal pipeline, Pa, obtained by collecting real-time data;

[0138] p An2 , static pressure of An2 section of pulverized coal pipeline, Pa, obtained by collecting real-time data;

[0139] C An , An the total resistance coefficient of the pulverized coal pipeline, the fixed value related to the pulverized coal pipeline can be calculated by referring to DL / T 5145-2012 "Technical Regulations for Design and Calculation of Pulverized Coal System in Thermal Power Plants";

[0140] Average primary air velocity of the coal pulverizer outlet duct, m / s;

[0141] δ A1 , A1 Relative deviation of primary air velocity in pulverized coal pipeline, %;

[0142] δ A2 , A2 Relative deviation of primary air velocity in pulverized coal pipeline, %;

[0143] δ An , relative deviation of primary wind speed in pulverized coal pipeline, %.

[0144] The calculation formulas for the primary wind speed in the pulverized coal pipeline (9) to (11) all have This item, and the values ​​of this item of each pulverized coal pipeline are equal, can be eliminated when calculating the relative deviation of the primary wind speed of each pulverized coal pipeline. Then the relative deviation of the primary wind speed of each pulverized coal pipeline at the pulverizer outlet is only related to the static pressure difference between the measurement section position 1 and the measurement section position 2 on each pulverized coal pipeline, and the total resistance coefficient of the pulverized coal pipeline between the measurement section position 1 and the measurement section position 2.

[0145] Step S406: by adjusting the adjustable shrinkage holes on the pulverized coal pipeline, the relative deviation of the primary wind speed of each pulverized coal pipeline is made less than ±5%.

[0146] By collecting data and calculating the relative deviation of the primary wind speed of each pulverized coal pipeline at the coal mill outlet, and then adjusting the adjustable shrinkage holes on each pulverized coal pipeline, the relative deviation of the primary wind speed of each pulverized coal pipeline is made less than ±5%. The primary wind speed leveling of the pulverized coal pipeline can be divided into two steps.

[0147] Step 1: Carry out a wind speed leveling test in a cold unit environment. Collect data and calculate the relative deviation of the primary wind speed of each coal pulverized pipe at the coal mill outlet, and then adjust the adjustable shrinkage holes on each coal pulverized pipe to make the relative deviation of the primary wind speed of each coal pulverized pipe less than ±5%.

[0148] Step 2: Carry out a wind speed leveling test in the hot environment of the unit. Collect data and calculate the relative deviation of the primary wind speed of each coal pulverizer outlet pipeline, and then adjust the adjustable shrinkage holes on each coal pulverizer pipeline to make the relative deviation of the primary wind speed of each coal pulverizer pipeline less than ±5%.

[0149] It can be known from the above technical scheme that the method for leveling the wind speed of the coal powder pipeline at the outlet of the pulverizer provided by the present invention selects two measuring sections on the coal powder pipeline, measures the static pressure difference, and calculates the wind speed based on the relationship between the pipeline resistance and the fluid flow rate, thereby avoiding complicated measuring equipment and operations and being easy to implement. In addition, the present invention is based on the basic principles of fluid mechanics and can be corrected in combination with the actual working conditions of the coal powder pipeline, so that the measurement results are accurate and reliable. Moreover, since the measuring device can be directly installed on the coal powder pipeline and collect data in real time, online monitoring of the wind speed can be achieved, which is convenient for timely detection and adjustment of the wind speed deviation and ensuring stable boiler combustion. Finally, by accurately measuring the wind speed of each pipeline through the present invention and adjusting the adjustable shrinkage hole according to the relative deviation of the wind speed, the wind speed of each pipeline can be effectively leveled so that its relative deviation is less than ±5%, thereby improving the combustion efficiency of the boiler and reducing the combustion deviation phenomenon.

[0150] like Figure 5 The figure shows a schematic diagram of the structure of a primary wind speed measuring device for a coal mill outlet coal pulverized pipe provided in an embodiment of the present application, the device comprises: a static pressure value measuring unit 510, a pipe resistance calculating unit 520, a relationship establishing unit 530 and a wind speed obtaining unit 540, which are sequentially connected. Among them:

[0151] The static pressure value measuring unit 510 is used to select two measuring sections on each pulverized coal pipeline at the outlet of the coal mill, and respectively install pressure transmitters on the two measuring sections to measure the static pressure values ​​of the two measuring sections.

[0152] The pipeline resistance calculation unit 520 is used to calculate the pipeline resistance according to the static pressure values ​​of the two measurement sections.

[0153] The relationship establishing unit 530 is used to establish a relationship between the pipeline resistance and the fluid flow rate.

[0154] The wind speed acquisition unit 540 is used to obtain the primary wind speed of each pulverized coal pipeline according to the relationship.

[0155] Preferably, the pipeline length and the local resistance coefficient between the two measurement sections selected on each of the above-mentioned pulverized coal pipelines remain unchanged during the measurement, and there is no component between the two measurement sections that will change the resistance coefficient.

[0156] Preferably, the length of the pipeline between two measurement sections selected on the same pulverized coal pipeline is more than 5 meters.

[0157] Preferably, the pipeline resistance calculation unit 520 calculates the pipeline resistance according to the static pressure values ​​of the two measurement sections, including:

[0158] According to the static pressure values ​​of the two measurement sections, the pipeline resistance is calculated using the following formula:

[0159] Δp=p1-p2;

[0160] In the above formula, Δp is the pipeline resistance; p1 is the pipeline static pressure value at the first measuring section; p2 is the pipeline static pressure value at the second section.

[0161] Preferably, the established relationship between the pipeline resistance and the fluid flow rate is:

[0162]

[0163] In the above formula, C is the total resistance coefficient of the pulverized coal pipeline, μ is the concentration of pulverized gas, ρ is the fluid density, and ω is the fluid flow rate.

[0164] Preferably, the wind speed acquisition unit 540 obtains the primary wind speed of each pulverized coal pipeline according to the relationship, including:

[0165] The fluid velocity of each pulverized coal pipeline is obtained using the following formula and is used as the corrected primary wind speed of the pipeline:

[0166]

[0167] The primary wind speed in the pulverized coal pipeline is measured by using a pitot tube and a micromanometer, and the primary wind speed to be corrected is calibrated by using the measurement result to obtain the corrected primary wind speed.

[0168] The detailed description of each of the above units can be found in the corresponding description in the aforementioned method embodiment, which will not be further elaborated here.

[0169] It can be seen from the above technical scheme that the primary wind speed measuring device for the coal powder pipeline at the outlet of the coal mill provided by the present invention selects two measuring sections on the coal powder pipeline, measures the static pressure difference, and calculates the wind speed based on the relationship between the pipeline resistance and the fluid flow rate, thereby avoiding complicated measuring equipment and operations and being easy to implement. In addition, the present invention is based on the basic principles of fluid mechanics and can be corrected in combination with the actual working conditions of the coal powder pipeline, so that the measurement results are accurate and reliable. Moreover, since the measuring device can be directly installed on the coal powder pipeline and collect data in real time, online monitoring of the wind speed can be realized, which is convenient for timely detection and adjustment of wind speed deviations and ensures stable boiler combustion.

[0170] like Figure 6The figure shows a schematic structural diagram of a primary wind speed leveling device for a pulverized coal pipeline at a coal mill outlet provided in an embodiment of the present application. The device includes: a primary wind speed measuring device 610, a relative deviation calculating unit 620 and a deviation adjusting unit 630.

[0171] The wind speed measuring device 610 can be seen in Figure 5 The corresponding measuring device is used to obtain the primary wind speed of each pulverized coal pipeline.

[0172] The relative deviation calculation unit 620 is used to calculate the relative deviation of the primary wind speed of each pulverized coal pipeline according to the primary wind speed measured by the primary wind speed measuring device.

[0173] The deviation adjustment unit 630 is used to adjust the adjustable shrinkage holes on the pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

[0174] Preferably, the above-mentioned deviation adjustment unit 630 is specifically used to, in the cold environment of the unit, adjust the adjustable shrinkage holes on each pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%; in the hot environment of the unit, adjust the adjustable shrinkage holes on each pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

[0175] It can be known from the above technical scheme that the primary wind speed leveling device for the coal powder pipeline at the outlet of the pulverizer provided by the present invention selects two measuring sections on the coal powder pipeline, measures the static pressure difference, and calculates the wind speed based on the relationship between the pipeline resistance and the fluid flow rate, thereby avoiding complicated measuring equipment and operations and being easy to implement. In addition, the present invention is based on the basic principles of fluid mechanics and can be corrected in combination with the actual working conditions of the coal powder pipeline, so that the measurement results are accurate and reliable. Moreover, since the measuring device can be directly installed on the coal powder pipeline and collect data in real time, online monitoring of the wind speed can be achieved, which is convenient for timely detection and adjustment of the wind speed deviation and ensuring stable boiler combustion. Finally, by accurately measuring the wind speed of each pipeline through the present invention and adjusting the adjustable shrinkage hole according to the relative deviation of the wind speed, the wind speed of each pipeline can be effectively leveled so that its relative deviation is less than ±5%, thereby improving the combustion efficiency of the boiler and reducing the combustion deviation phenomenon.

[0176] Figure 7 is a schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 7 The electronic device shown is a general data processing device, which includes a general computer hardware structure, which at least includes a processor 801 and a memory 802. The processor 801 and the memory 802 are connected via a bus 803. The memory 802 is suitable for storing one or more instructions or programs executable by the processor 801. The one or more instructions or programs are executed by the processor 801 to implement the steps in the primary wind speed measurement method and leveling method of the coal mill outlet coal powder pipeline.

[0177] The processor 801 may be an independent microprocessor or a collection of one or more microprocessors. Thus, the processor 801 executes the commands stored in the memory 802 to execute the method flow of the embodiment of the present invention as described above to realize the processing of data and the control of other devices. The bus 803 connects the above-mentioned multiple components together, and at the same time connects the above-mentioned components to the display controller 804 and the display device and the input / output (I / O) device 805. The input / output (I / O) device 805 may be a mouse, a keyboard, a modem, a network interface, a touch input device, a somatosensory input device, a printer, and other devices known in the art. Typically, the input / output (I / O) device 805 is connected to the system via an input / output (I / O) controller 806.

[0178] The memory 802 may store software components such as an operating system, a communication module, an interaction module, and an application program. Each of the modules and applications described above corresponds to a set of executable program instructions that implement one or more functions and methods described in the embodiments of the invention.

[0179] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the primary wind speed measurement method and the leveling method of the pulverized coal pipeline at the outlet of the coal mill are implemented.

[0180] An embodiment of the present invention further provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the primary wind speed measurement method and leveling method of the pulverized coal pipeline at the outlet of the coal mill.

[0181] In summary, the method for measuring the primary wind speed of the coal powder pipeline at the outlet of the coal mill, the method for leveling and the device provided by the present invention, by selecting two measuring sections on the coal powder pipeline, measuring the static pressure difference, and calculating the wind speed based on the relationship between the pipeline resistance and the fluid flow rate, avoids complicated measuring equipment and operations, and is easy to implement. In addition, the present invention is based on the basic principles of fluid mechanics, and can be corrected in combination with the actual working conditions of the coal powder pipeline, and the measurement results are accurate and reliable. Moreover, since the measuring device can be directly installed on the coal powder pipeline and collect data in real time, online monitoring of the wind speed can be achieved, which is convenient for timely detection and adjustment of wind speed deviations, and ensures stable boiler combustion. Finally, by accurately measuring the wind speed of each pipeline through the present invention, and adjusting the adjustable shrinkage hole according to the relative deviation of the wind speed, the wind speed of each pipeline can be effectively leveled, so that its relative deviation is less than ±5%, thereby improving the combustion efficiency of the boiler and reducing the combustion deviation phenomenon.

[0182] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. Many features and advantages of these embodiments are clear from this detailed description, and therefore the claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. In addition, since many modifications and changes are readily apparent to those skilled in the art, the embodiments of the present invention are not intended to be limited to the precise structure and operation illustrated and described, but all suitable modifications and equivalents that fall within their scope may be included.

[0183] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0184] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0185] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0186] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0187] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for measuring the primary wind speed of a coal pulverizer outlet coal pulverizer pipeline, characterized in that: The method comprises: Select two measuring sections on each pulverized coal pipeline at the outlet of the coal mill, and install pressure transmitters on the two measuring sections respectively to measure the static pressure values ​​of the two measuring sections; Calculating pipeline resistance according to the static pressure values ​​of the two measuring sections; Establishing a relationship between the pipeline resistance and the fluid flow rate; The primary wind speed of each pulverized coal pipeline is obtained according to the relationship.

2. The method for measuring primary wind speed at the outlet coal powder pipeline of a coal mill according to claim 1, characterized in that: The pipeline length and the local resistance coefficient between two measurement sections selected on each pulverized coal pipeline remain unchanged during the measurement, and there is no component between the two measurement sections that will change the resistance coefficient.

3. The method for measuring primary wind speed at the outlet coal powder pipeline of a coal mill according to claim 1, characterized in that: The length of the pipeline between two measurement sections selected on the same pulverized coal pipeline is more than 5 meters.

4. The method for measuring primary wind speed at the outlet coal powder pipeline of a coal mill according to claim 1, characterized in that: The calculating of pipeline resistance according to the static pressure values ​​of the two measuring sections comprises: According to the static pressure values ​​of the two measurement sections, the pipeline resistance is calculated using the following formula: Δp=p1-p2; In the above formula, Δp is the pipeline resistance; p1 is the pipeline static pressure value at the first measuring section; p2 is the pipeline static pressure value at the second section.

5. The method for measuring primary wind speed at the outlet coal powder pipeline of a coal mill according to claim 4, characterized in that: The established relationship between the pipeline resistance and the fluid flow rate is: In the above formula, C is the total resistance coefficient of the pulverized coal pipeline, μ is the concentration of pulverized gas, ρ is the fluid density, and ω is the fluid flow rate.

6. The method for measuring primary wind speed at the outlet coal powder pipeline of a coal mill according to claim 5, characterized in that: The method of obtaining the primary wind speed of each pulverized coal pipeline according to the relationship includes: The fluid flow rate of each pulverized coal pipeline is obtained using the following formula, which is used as the corrected primary wind speed of the corresponding pipeline: The primary wind speed in the pulverized coal pipeline is measured by using a pitot tube and a micromanometer, and the primary wind speed to be corrected is calibrated by using the measurement result to obtain the corrected primary wind speed.

7. A method for adjusting the primary wind speed of a coal mill outlet coal pulverized pipeline, characterized in that: The method comprises: Obtaining the primary wind speed of each pulverized coal pipeline by the method described in any one of claims 1 to 6; According to the obtained primary wind speed of each pulverized coal pipeline, the relative deviation of the primary wind speed of each pulverized coal pipeline is calculated; By adjusting the adjustable shrinkage holes on the pulverized coal pipeline, the relative deviation of the primary wind speed of each pulverized coal pipeline is made less than ±5%.

8. A method for adjusting the primary wind speed of a coal mill outlet coal pulverized pipeline as claimed in claim 7, characterized in that: The method of adjusting the adjustable shrinkage holes on the pulverized coal pipeline to make the relative deviation of the primary wind speed of each pulverized coal pipeline less than ±5% includes: Under the cold condition of the unit, the relative deviation of the primary air velocity of each pulverized coal pipeline is made less than ±5% by adjusting the adjustable shrinkage holes on each pulverized coal pipeline; Under the hot state of the unit, the relative deviation of the primary wind speed of each pulverized coal pipeline is made less than ±5% by adjusting the adjustable shrinkage holes on each pulverized coal pipeline.

9. A device for measuring primary wind speed at the outlet coal pulverizer pipeline, characterized in that: The device comprises: A static pressure value measuring unit is used to select two measuring sections on each pulverized coal pipeline at the outlet of the coal mill, and respectively install pressure transmitters on the two measuring sections to measure the static pressure values ​​of the two measuring sections; A pipeline resistance calculation unit, used for calculating the pipeline resistance according to the static pressure values ​​of the two measurement sections; A relationship establishing unit, used to establish a relationship between the pipeline resistance and the fluid flow rate; The wind speed acquisition unit is used to obtain the primary wind speed of each pulverized coal pipeline according to the relationship.

10. A primary wind speed leveling device for a coal mill outlet coal pulverized pipeline, characterized in that: The device comprises: The primary wind speed measuring device according to claim 9; A relative deviation calculation unit, used to calculate the relative deviation of the primary wind speed of each pulverized coal pipeline according to the primary wind speed measured by the primary wind speed measuring device; The deviation adjustment unit is used to adjust the adjustable shrinkage holes on the pulverized coal pipeline so that the relative deviation of the primary wind speed of each pulverized coal pipeline is less than ±5%.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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