阅读说明：本技术 一种基于短期离线实测数据的燃煤锅炉高温区烟温测试装置及修正计算方法 (Coal-fired boiler high-temperature area smoke temperature testing device based on short-term off-line measured data and correction calculation method ) 是由 项群扬 牟文彪 滕敏华 范海东 刘凯锐 邱波 胡红伟 于 2020-06-23 设计创作，主要内容包括：本发明涉及一种基于短期离线实测数据的燃煤锅炉高温区烟温测试装置,包括：锅炉、屏式过热器、高温过热器、高温再热器、低温过热器、低温再热器、省煤器、临时热电偶组、炉顶小室、顶棚过热器、包墙过热器和数据采集仪；所述炉顶小室位于水平烟道的顶部,所述顶棚过热器位于炉膛和水平烟道上部,所述包墙过热器位于水平烟道四周。本发明的有益效果是：成本低廉,克服了热电偶在高温环境下无法长时间使用的缺陷,仅需要安装一批临时使用5～15天的热电偶,相比于光学和声学的直接测温方法,成本大幅降低90％以上；可在高温区多个不同烟道截面分别布置烟气温度测点,能够精确的获得不同烟道截面的烟气温度。(The invention relates to a coal-fired boiler high-temperature area smoke temperature testing device based on short-term off-line measured data, which comprises: the system comprises a boiler, a screen type superheater, a high-temperature reheater, a low-temperature superheater, a low-temperature reheater, an economizer, a temporary thermocouple group, a furnace top small chamber, a ceiling superheater, a wall-wrapping superheater and a data acquisition instrument; the furnace top small chamber is positioned at the top of the horizontal flue, the ceiling superheater is positioned at the upper parts of the furnace chamber and the horizontal flue, and the wall-wrapping superheater is positioned around the horizontal flue. The invention has the beneficial effects that: the cost is low, the defect that the thermocouple cannot be used for a long time in a high-temperature environment is overcome, only a batch of thermocouples which are temporarily used for 5-15 days need to be installed, and compared with an optical and acoustic direct temperature measurement method, the cost is greatly reduced by more than 90%; flue gas temperature measuring points can be respectively arranged on a plurality of different flue sections in a high-temperature area, and the flue gas temperatures of the different flue sections can be accurately obtained.)

1. The utility model provides a coal fired boiler high temperature district gas temperature testing arrangement based on short-term off-line measured data which characterized in that includes: the system comprises a boiler (1), a platen superheater, a high-temperature reheater, a low-temperature superheater, a low-temperature reheater, an economizer, a temporary thermocouple group (5), a furnace top small chamber (8), a ceiling superheater (9), a wall-wrapped superheater (10) and a data acquisition instrument (14); the furnace top small chamber (8) is positioned at the top of the horizontal flue, the ceiling superheater (9) is positioned at the upper parts of the furnace chamber and the horizontal flue, and the wall-wrapping superheater (10) is positioned around the horizontal flue;

a platen superheater outlet section (6) is arranged on a heating surface in the platen superheater outlet flue; a high-temperature superheater outlet section (7) is arranged on the heating surface in the high-temperature superheater outlet flue; a low-temperature superheater inlet flue gas temperature online measuring point (2) is arranged on a heated surface in a low-temperature superheater inlet flue, an economizer inlet flue gas temperature online measuring point (3) is arranged on the heated surface in an economizer inlet flue, and an economizer outlet flue gas temperature online measuring point (4) is arranged on the heated surface in an economizer outlet flue; the online measuring point (2) for the inlet flue gas temperature of the low-temperature superheater, the online measuring point (3) for the inlet flue gas temperature of the economizer and the online measuring point (4) for the outlet flue gas temperature of the economizer are all positioned in a tail flue of the boiler (1);

the outlet of the boiler (1) is connected with a platen superheater inlet flue, a platen superheater outlet flue is connected with a high-temperature superheater inlet flue, a high-temperature superheater outlet flue is connected with a high-temperature reheater inlet flue, a high-temperature reheater outlet flue is connected with a low-temperature superheater inlet flue, a low-temperature superheater outlet flue is connected with a low-temperature reheater inlet flue, and a low-temperature reheater outlet flue is connected with an economizer inlet flue;

a hearth outlet section (13) is arranged at a hearth outlet of the boiler (1), a temporary thermocouple group (5) is arranged on the hearth outlet section (13), a smoke measuring hole group (11) is arranged above the hearth outlet section (13), the smoke measuring hole group (11) is positioned at the top of a horizontal flue, and the smoke measuring hole group (11) also penetrates through a small chamber (8) at the top of the boiler and is communicated with the flue at the hearth outlet section (13); the smoke measuring hole groups (11) are distributed along the outlet section (13) of the hearth from the left side of the hearth to the right side of the hearth at equal intervals, and the probe of the temporary thermocouple group (5) extends downwards from the top of the hearth to an actual measurement position (12) of a smoke temperature test of the outlet section (13) of the hearth through the smoke measuring hole groups (11); the non-probe end of the temporary thermocouple group (5) is connected with a data acquisition instrument (14).

2. The coal-fired boiler high-temperature zone smoke temperature testing device based on short-term off-line measured data according to claim 1, characterized in that: 2-4 thermocouples are inserted into each smoke measuring hole group (11).

3. The correction calculation method of the coal-fired boiler high-temperature area smoke temperature test device based on the short-term off-line measured data as claimed in claim 1 is characterized by comprising the following steps:

step 1, dividing each heating surface of a boiler (1) into a convection heating surface and a radiation or semi-radiation heating surface according to the heat absorption condition of each heating surface of the boiler (1); calculating the inlet flue gas temperature of each heating surface section by section according to the opposite direction of flue gas flow by using the existing on-line working medium side parameters and the existing economizer outlet flue gas side parameters of the tail flue;

step 1.1, aiming at the convection heating surface, knowing the outlet flue gas temperature of the heating surface, the inlet parameters of the working medium side and the outlet parameters of the working medium side, and calculating to obtain the inlet flue gas enthalpy value H' of the heating surface:

in the formula, H 'is the enthalpy of steam at the inlet of the heating surface and has the unit of KJ/Kg, H' is the enthalpy of steam at the outlet of the heating surface and has the unit of KJ/Kg, H 'is the enthalpy of smoke at the inlet of the heating surface and has the unit of KJ/Kg, H' is the enthalpy of smoke at the outlet of the heating surface and has the unit of KJ/Kg, D is the flow of working medium at the heating surface and has the unit of Kg/s, phi is the heat retention coefficient which is the ratio of the heat absorbed by the working medium at the heating surface to the heat emitted by the smoke, and delta α is the air leakage coefficient;

calculating the inlet flue gas temperature T according to the functional relation between the inlet flue gas enthalpy value H' of the heating surface and the inlet flue gas temperature T in the formula (2):

H'＝C0+C1T+C2T²+C3T³+C4T⁴+C5T⁵(2)

in the above formula, C0, C1, C2, C3, C4 and C5 are all correlation coefficients and are obtained by consulting boiler performance test regulations; t is the inlet flue gas temperature of the heating surface and the unit is K;

step 1.2, performing hypothesis and iterative calculation on a radiation or semi-radiation heating surface: assuming the temperature of the flue gas at the outlet of the hearth, calculating to obtain the effective coefficient of heat of the water-cooled wall and the direct radiant quantity at the outlet of the hearth, establishing a heat balance equation of a semi-radiation heating surface, and solving a calculated value of the temperature of the flue gas at the outlet of the hearth; when the deviation between the calculated value of the temperature of the flue gas at the outlet of the hearth and the assumed value is less than 1 ℃, ending the iteration to obtain the final calculated value Tf of the temperature of the flue gas at the outlet of the hearth_cal；

Step 2, when the boiler is stopped and overhauled, a smoke measuring hole group (11) is arranged above the outlet section (13) of the hearth to test the smoke temperature; the smoke hole group (11) is positioned at the top of the horizontal flue and penetrates through the small chamber (8) at the top of the furnace to be communicated with the flue at the position of the outlet section (13) of the hearth; arranging flue gas temperature measuring points of a hearth outlet section (13) according to the depth and the width of a flue by an equal section grid method, arranging flue gas measuring holes at intervals of 1-2 meters, simultaneously arranging 1-4 armored thermocouples on each flue gas measuring hole, and enabling the insertion depth of each armored thermocouple to be different; connecting all the armored thermocouples with a data acquisition instrument (14);

step 3, measuring the flue gas temperature at the position of the outlet section (13) of the hearth by using the temporary thermocouple group (5), and collecting the flue gas temperature data within the total time length T in real time through a data acquisition instrument (14); setting the acquisition interval of the data acquisition instrument (14) to be tau to obtain

step 4, measuring the flue gas temperature Tf of each group_m,iAveraging to obtain the average value Tf of the flue gas temperature at the outlet of the hearth_mThe average value Tf of the temperature of the flue gas at the outlet of the hearth_mAnd the final calculated value Tf of the temperature of the flue gas at the outlet of the hearth obtained in the step 1.2_calPerforming polynomial fitting to obtain Tf_mAnd Tf_calThe correction function relationship of (1):

Tf_m＝f₁(Tf_cal) (3)

after the actual measurement of the flue gas temperature data within the total time length T is completed, according to the correction function relationship between the actual measurement value of the hearth outlet flue gas temperature and the final calculation value of the hearth outlet flue gas temperature in the formula (1), according to the final calculation value Tf of the hearth outlet flue gas temperature obtained in the step 1.2_calReal-time calculating the corrected value of the temperature of the flue gas at the outlet of the furnace at any determined time point

In the above formula, the subscript t_iA certain determined point in time;

step 5, according to step 3

Tf_m,max＝f₂(Tf_cal) (5)

and comparing the highest value of the flue gas temperature at the outlet of the hearth with the designed flue gas temperature at the heating surface to judge whether the heating surface has the risk of tube explosion.

4. The correction calculation method of the coal-fired boiler high-temperature area smoke temperature test device based on the short-term off-line measured data as claimed in claim 3, wherein the on-line working medium side parameters in the step 1 comprise: heating surface inlet temperature, heating surface inlet pressure, heating surface outlet temperature, heating surface outlet pressure and working medium flow; if the selected heating surface is the heating surface of the desuperheating water, the parameters of the on-line working medium side further comprise the temperature of the desuperheating water, the pressure of the desuperheating water and the flow parameters.

5. The correction calculation method of the coal-fired boiler high-temperature zone smoke temperature test device based on the short-term off-line measured data as claimed in claim 3, characterized in that: the convection heating surface in the step 1 comprises a high-temperature reheater, a low-temperature superheater, a low-temperature reheater and an economizer; the radiation or semi-radiation heating surface in the step 1 comprises a platen superheater and a high-temperature superheater.

6. The correction calculation method for the coal-fired boiler high-temperature zone smoke temperature test device based on the short-term off-line measured data according to claim 3, characterized in that the following steps are further performed between the step 2 and the step 3: and arranging the smoke hole measuring group (11) on the platen superheater outlet section (6) and the high-temperature superheater outlet section (7) simultaneously according to the step 2.

7. The correction calculation method of the coal-fired boiler high-temperature zone smoke temperature test device based on the short-term off-line measured data as claimed in claim 3, characterized in that: and 3, selecting the total time T according to the service life of the thermocouple, wherein the value range is 5-15 days.

Technical Field

The invention relates to the technical field of coal burning of coal-fired power plants, in particular to a coal-fired boiler high-temperature area smoke temperature testing device and a correction calculation method based on short-term off-line measured data.

Background

At present, coal-fired power plant boilers develop towards the trend of high capacity and high parameter, and the safety and the economical efficiency of boiler operation are important concerns of researchers. The flue gas temperature at each heating surface of the boiler hearth has important significance for judging the safety of the metal pipe wall of the heating surface and the ash deposition state of the heating surface.

At present, a large coal-fired power station boiler is generally provided with flue gas temperature measuring points on heating surfaces such as an inlet and an outlet of an air preheater of a tail flue, an inlet and an outlet of an SCR denitration system, an inlet and an outlet of an economizer and the like; and a smoke temperature measuring point is also arranged at the inlet of the heating surface of the partial boiler, such as a low-temperature superheater, a low-temperature reheater and the like. However, in the front and back of the heating surface near the furnace outlet and the horizontal flue, such as the furnace outlet (especially in front of a platen superheater), the front and back of a high-temperature superheater, and the front and back of a high-temperature reheater, because the flue gas temperature is high and reaches 800-1000 ℃, a flue gas measuring point is not usually installed due to the deficiency of a corresponding measuring means. However, the measurement of the flue gas temperature at the high-temperature section has strong guiding significance for preventing the heating surface from tube explosion, optimizing the operation of the soot blower and the like.

The common direct measurement means of the temperature of the high-temperature flue gas comprises a contact type and a non-contact type. The non-contact measurement method mainly comprises an acoustic wave method and an optical method, but has the main problems that the measurement is influenced by a plurality of interference factors such as air flow, flame and the like, the measurement error is large, corresponding hardware and software equipment are expensive, and the installation and maintenance are difficult, so that the non-contact measurement method is usually only used for one section of a hearth outlet and has poor accuracy. The contact type measuring method is to install a thermocouple and other contact type temperature measuring equipment on a high-temperature heating surface, but because of the problems of high flue gas temperature, serious abrasion and the like, the thermocouple generally has short service life and cannot be used for a long time, so the contact type measuring method can only be installed on the pipe wall of the heating surface in a high-temperature area, namely the wall temperature is measured instead of the flue gas temperature.

The other method for obtaining the flue gas temperature of the high-temperature area is a soft measurement method, namely the flue gas temperature of each counter-flow heating surface is calculated and reversely deduced in a countercurrent mode through heat balance according to the heat balance formula of a semi-empirical semi-theory from the existing flue gas measured data of the tail heating surface through the standard method for calculating the heat of a boiler unit. However, the method has the problems that the horizontal flue is not only arranged outside the heating surface in the flue, but also comprises a ceiling superheater, a middle partition heating surface and surrounding wall heating surfaces, working medium parameters of the heating surfaces and the flue at corresponding positions usually have no measuring points, so that the influence of the heating surfaces is generally ignored in the heat balance calculation, and the calculated flue gas temperature has a larger error from an actual result. In addition, for judging the risk of tube explosion of the metal tube wall of the heating surface, the highest smoke temperature of the cross section is an important influence parameter; however, the working medium parameters at the steam-water side can only correspond to the left and right side flues, so the flue gas temperature obtained by heat balance calculation can only reflect the average flue gas temperature of the single side flue, and the highest flue gas temperature of the flue gas section cannot be calculated.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a coal-fired boiler high-temperature area smoke temperature testing device and a correction calculation method based on short-term off-line measured data.

The invention provides a coal-fired boiler high-temperature area smoke temperature correction calculation method based on short-term off-line measured data; the flue gas temperature of the outlet of the hearth is actually measured through a high-temperature thermocouple and a data acquisition instrument which are installed in a short period, and a flue gas temperature calculation model of each section is established according to a thermal balance principle to obtain a calculated value of the flue gas temperature of the outlet of the hearth. Fitting the actually measured smoke temperature data and the calculated value to obtain a functional relation, and obtaining a more accurate corrected value of the smoke temperature at the outlet of the hearth in real time for a long time according to the functional relation and the calculated value of the smoke temperature; and obtaining the corrected value of the highest smoke temperature at the outlet of the hearth according to the actually measured smoke temperature distribution data.

This kind of coal fired boiler high temperature district smoke temperature testing arrangement based on short-term off-line measured data includes: the system comprises a boiler, a screen type superheater, a high-temperature reheater, a low-temperature superheater, a low-temperature reheater, an economizer, a temporary thermocouple group, a furnace top small chamber, a ceiling superheater, a wall-wrapping superheater and a data acquisition instrument; the furnace top small chamber is positioned at the top of the horizontal flue, the ceiling superheater is positioned at the upper parts of the furnace chamber and the horizontal flue, and the wall-wrapping superheater is positioned around the horizontal flue;

a platen superheater outlet section is arranged on a heating surface in the platen superheater outlet flue; a high-temperature superheater outlet cross section is arranged on a heating surface in the high-temperature superheater outlet flue; the on-line measuring point of the inlet flue gas temperature of the low-temperature superheater is arranged on the heated surface in the inlet flue of the low-temperature superheater, the on-line measuring point of the inlet flue gas temperature of the economizer is arranged on the heated surface in the inlet flue of the economizer, and the on-line measuring point of the outlet flue gas temperature of the economizer is arranged on the heated surface in the outlet flue of the economizer; the online measuring point of the low-temperature superheater inlet flue gas temperature, the online measuring point of the economizer inlet flue gas temperature and the online measuring point of the economizer outlet flue gas temperature are all positioned in a tail flue of the boiler;

the boiler outlet is connected with a platen superheater inlet flue, a platen superheater outlet flue is connected with a high-temperature superheater inlet flue, a high-temperature superheater outlet flue is connected with a high-temperature reheater inlet flue, a high-temperature reheater outlet flue is connected with a low-temperature superheater inlet flue, a low-temperature superheater outlet flue is connected with a low-temperature reheater inlet flue, and a low-temperature reheater outlet flue is connected with an economizer inlet flue;

a hearth outlet of the boiler is provided with a hearth outlet section, a temporary thermocouple group is arranged on the hearth outlet section, a smoke measuring hole group is arranged above the hearth outlet section and is positioned at the top of the horizontal flue, and the smoke measuring hole group also penetrates through the small chamber at the top of the boiler and is communicated with the flue at the hearth outlet section; the smoke hole measuring groups are distributed along the outlet section of the hearth from the left side of the hearth to the right side of the hearth at equal intervals, and the probes of the temporary thermocouple groups extend downwards from the top of the hearth to the actual measurement positions of the smoke temperature test of the outlet section of the hearth through the smoke hole measuring groups; the non-probe end of the temporary thermocouple group is connected with a data acquisition instrument, and the smoke temperature data at the actual measurement position of the smoke temperature test is acquired in real time.

Preferably, 2-4 thermocouples are inserted into each smoke hole testing group.

The correction calculation method of the coal-fired boiler high-temperature area smoke temperature testing device based on short-term off-line measured data specifically comprises the following steps:

step 1, dividing each heating surface of a boiler into a convection heating surface and a radiation or semi-radiation heating surface according to the heat absorption condition of each heating surface of the boiler; according to the basic principle of heat balance of the whole boiler and each local heating surface, the inlet flue gas temperature of each heating surface is calculated section by section according to the opposite direction of flue gas flow by utilizing the existing on-line working medium side parameters and the existing economizer outlet flue gas side parameters of the tail flue;

step 1.1, aiming at the convection heating surface, knowing the outlet flue gas temperature of the heating surface, the inlet parameters of the working medium side and the outlet parameters of the working medium side, and calculating to obtain the inlet flue gas enthalpy value H' of the heating surface:

in the formula, H 'is the enthalpy of steam at the inlet of the heating surface and has the unit of KJ/Kg, H' is the enthalpy of steam at the outlet of the heating surface and has the unit of KJ/Kg, H 'is the enthalpy of smoke at the inlet of the heating surface and has the unit of KJ/Kg, H' is the enthalpy of smoke at the outlet of the heating surface and has the unit of KJ/Kg, D is the flow of working medium at the heating surface and has the unit of Kg/s, phi is the heat retention coefficient which is the ratio of the heat absorbed by the working medium at the heating surface to the heat emitted by the smoke, and delta α is the air leakage coefficient;

the theoretical enthalpy of the cold air is KJ/Kg; bj is the fuel consumption, and the unit is Kg/s;

calculating the inlet flue gas temperature T according to the functional relation between the inlet flue gas enthalpy value H' of the heating surface and the inlet flue gas temperature T in the formula (2):

H'＝C0+C1T+C2T²+C3T³+C4T⁴+C5T⁵(2)

in the above formula, C0, C1, C2, C3, C4 and C5 are all correlation coefficients and are obtained by consulting boiler performance test regulations; t is the inlet flue gas temperature of the heating surface and the unit is K;

step 1.2, aiming at a radiation or semi-radiation heating surface, as radiation heat transfer is involved and the temperature of the flue gas in a high-temperature area is unknown, hypothesis and iterative calculation are required: assuming the temperature of the flue gas at the outlet of the hearth, calculating to obtain the effective coefficient of heat of the water-cooled wall and the direct radiant quantity at the outlet of the hearth, establishing a heat balance equation of semi-radiation heating surfaces such as a screen superheater and a high-temperature superheater, and solving a calculated value of the temperature of the flue gas at the outlet of the hearth; when the deviation between the calculated value of the temperature of the flue gas at the outlet of the hearth and the assumed value is less than 1 ℃, ending the iteration to obtain the final calculated value Tf of the temperature of the flue gas at the outlet of the hearth_cal(ii) a Due to the calculation of Tf_calThe required data are all from the online meter, so that the real-time calculation can be realized;

step 2, when the boiler is stopped and overhauled, a smoke gas measuring hole group is arranged above the outlet section of the hearth to test the smoke gas temperature; the smoke hole group is positioned at the top of the horizontal flue and is communicated with the flue at the section of the outlet of the hearth through the small chamber at the top of the furnace; arranging flue gas temperature measuring points on the section of the outlet of the hearth according to the depth and the width of a flue by an equal-section grid method, arranging flue gas measuring holes at intervals of 1-2 meters, and simultaneously arranging 1-4 armored thermocouples on each flue gas measuring hole, wherein the insertion depth of each armored thermocouple is different; connecting all the armored thermocouples with a data acquisition instrument, and acquiring flue gas temperature data of each position of the outlet section of the hearth in real time;

step 3, measuring the flue gas temperature at the outlet section of the hearth by using the temporary thermocouple group, and collecting the flue gas temperature data within the total time length T in real time by using a data acquisition instrument; setting the acquisition interval of the data acquisition instrument to be tau to obtain

Flue gas temperature measured value Tf at outlet section of group furnace_m,iWherein i represents the serial number of the measuring point; due to the problems of high temperature, abrasion and the like, the service life of the thermocouple is short and generally does not exceed 1 month, and when the thermocouple in the temporary thermocouple group is damaged, the thermocouple is pulled out through the smoke measuring hole group;

step 4, measuring the flue gas temperature Tf of each group_m,iAveraging to obtain the average value Tf of the flue gas temperature at the outlet of the hearth_mThe average value Tf of the temperature of the flue gas at the outlet of the hearth_mAnd the final calculated value Tf of the temperature of the flue gas at the outlet of the hearth obtained in the step 1.2_calPerforming polynomial fitting to obtain Tf_mAnd Tf_calThe correction function relationship of (1):

Tf_m＝f₁(Tf_cal) (3)

due to calculation of the value Tf_calCan be calculated in real time according to the existing on-line measuring points of the boiler, after the actual measurement of the flue gas temperature data within the total time length T is completed, according to the correction function relationship between the actual measurement value of the hearth outlet flue gas temperature and the final calculation value of the hearth outlet flue gas temperature in the formula (1), the final calculation value Tf of the hearth outlet flue gas temperature obtained in the step 1.2 is calculated_calReal-time calculating the corrected value of the temperature of the flue gas at the outlet of the furnace at any determined time point

In the above formula, the subscript t_iA certain determined point in time;

obtaining a more accurate result of the temperature of the flue gas at the outlet of the hearth at any time according to the formula (4);

step 5, according to step 3Flue gas temperature measured value Tf at outlet section of group furnace_m,iObtaining the maximum value Tf of the temperature of the flue gas at the outlet of the hearth_m,maxAnd the final calculated value Tf of the temperature of the flue gas at the outlet of the hearth obtained in the step 1.2 is summed_calPerforming polynomial fittingTo obtain Tf_m,maxAnd Tf_calThe correction function relationship of (1):

Tf_m,max＝f₂(Tf_cal) (5)

the method can obtain a relatively accurate result of the highest flue gas temperature of the outlet section of the hearth in real time for a long time, and compares the highest value of the flue gas temperature of the outlet of the hearth with the designed flue gas temperature of the heating surface (the platen superheater) to judge whether the heating surface has a risk of tube explosion.

Preferably, the online working medium side parameters in the step 1 include: heating surface inlet temperature, heating surface inlet pressure, heating surface outlet temperature, heating surface outlet pressure and working medium flow; if the selected heating surface is the heating surface of the desuperheating water, the parameters of the on-line working medium side further comprise the temperature of the desuperheating water, the pressure of the desuperheating water and the flow parameters.

Preferably, the convection heating surface in the step 1 comprises a high-temperature reheater, a low-temperature superheater, a low-temperature reheater and an economizer; the radiation or semi-radiation heating surface in the step 1 comprises a platen superheater and a high-temperature superheater.

Preferably, the following steps are also provided between the step 2 and the step 3: and (3) arranging the smoke hole measuring groups on the outlet section of the platen superheater and the outlet section of the high-temperature superheater simultaneously according to the step (2).

Preferably, the total duration T in the step 3 is selected according to the service life of the thermocouple, and the value range is 5-15 days.

Preferably, referring to the step 1, calculating the flue gas temperature of the outlet section of the platen superheater and the outlet section of the high-temperature superheater according to the heat balance; referring to the steps 2 to 5, the flue gas temperature is actually measured at the section and the section off line, so that a correction function relation between the actually measured flue gas temperature and the calculated flue gas temperature can be obtained, and the flue gas temperature result obtained by correction calculation is more accurate than that obtained by the previous method.

Preferably, the horizontal flue and the tail flue of the boiler are divided into left and right sides, and a correction function relation between the measured values of the left/right side flue gas temperatures and the calculated values of the left/right side flue gas temperatures is obtained by fitting the same method as the steps 2 to 5 according to the existing online measuring points of the left/right side flues and the heating surfaces, so that the correction values of the average flue gas temperatures and the highest flue gas temperatures on the two sides are respectively calculated.

The invention has the beneficial effects that:

1) the cost is low. The defect that the thermocouple cannot be used for a long time in a high-temperature environment is overcome, only a batch of thermocouples which are temporarily used for 5-15 days need to be installed, and compared with an optical and acoustic direct temperature measurement method, the cost is greatly reduced by more than 90%.

2) The flue gas temperature result is accurate. The invention corrects the calculation result of the flue gas temperature according to the actual measurement result of the flue gas temperature, can eliminate the huge error caused by heat exchange of heating surfaces such as ceilings, wrapping walls and the like which are difficult to process in the calculation value of the flue gas temperature to the maximum extent, and the accuracy degree of the obtained result of the flue gas temperature is far higher than that of the calculation result of soft measurement.

3) Flue gas temperature measuring points can be respectively arranged on a plurality of different flue sections in a high-temperature area, and the flue gas temperatures of the different flue sections can be accurately obtained.

4) The average temperature and the highest temperature of the flue gas of each section of the high-temperature area can be accurately obtained in real time through the calculated value of the flue gas temperature and the correction function, the safety of the metal pipe wall of the heating surface can be guaranteed, and soot blowing of the corresponding heating surface can be guided.

Drawings

FIG. 1 is a schematic diagram of a system of a boiler heating surface and a schematic diagram of the positions of relevant smoke temperature measuring points;

FIG. 2 is a diagram of arrangement of measurement points for the smoke temperature at the outlet of the furnace.

Description of reference numerals: the device comprises a boiler 1, a screen superheater, a high-temperature reheater, a low-temperature superheater, a low-temperature reheater, an economizer, a low-temperature superheater inlet flue gas temperature online measuring point 2, an economizer inlet flue gas temperature online measuring point 3, an economizer outlet flue gas temperature online measuring point 4, a temporary thermocouple group 5, a screen superheater outlet section 6, a high-temperature superheater outlet section 7, a furnace top small chamber 8, a ceiling superheater 9, a wall-wrapped superheater 10, a flue gas measuring hole group 11, an actual measurement position 12 for flue gas temperature test, a furnace outlet section 13 and a data acquisition instrument 14.

Detailed Description

The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for a person skilled in the art, several modifications can be made to the invention without departing from the principle of the invention, and these modifications and modifications also fall within the protection scope of the claims of the present invention.

The invention provides a coal-fired boiler high-temperature area smoke temperature testing device based on short-term off-line measured data and a correction calculation method, and mainly relates to a system, a measuring point and equipment which are shown in figures 1 and 2. FIG. 1 is a schematic diagram of a system of a boiler heating surface and a schematic diagram of positions of relevant smoke temperature measuring points, and FIG. 2 is a layout diagram of smoke temperature measuring points at a hearth outlet.

Coal fired boiler high temperature district gas temperature testing arrangement based on short-term off-line measured data includes: the system comprises a boiler 1, a platen superheater, a high-temperature reheater, a low-temperature superheater, a low-temperature reheater, an economizer, a temporary thermocouple group 5, a furnace top small chamber 8, a ceiling superheater 9, a wall-covered superheater 10 and a data acquisition instrument 14; the furnace top small chamber 8 is positioned at the top of the horizontal flue, the ceiling superheater 9 is positioned at the upper parts of the furnace chamber and the horizontal flue, and the wall-wrapping superheater 10 is positioned at the periphery of the horizontal flue;

a platen superheater outlet section 6 is arranged on a heated surface in the platen superheater outlet flue; a high-temperature superheater outlet section 7 is arranged on a heating surface in the high-temperature superheater outlet flue; a low-temperature superheater inlet flue gas temperature online measuring point 2 is arranged on a heated surface in a low-temperature superheater inlet flue, an economizer inlet flue gas temperature online measuring point 3 is arranged on the heated surface in an economizer inlet flue, and an economizer outlet flue gas temperature online measuring point 4 is arranged on the heated surface in an economizer outlet flue; the online measuring point 2 for the inlet flue gas temperature of the low-temperature superheater, the online measuring point 3 for the inlet flue gas temperature of the economizer and the online measuring point 4 for the outlet flue gas temperature of the economizer are all positioned in a tail flue of the boiler 1;

an outlet of the boiler 1 is connected with an inlet flue of the platen superheater, an outlet flue of the platen superheater is connected with an inlet flue of the high-temperature superheater, an outlet flue of the high-temperature superheater is connected with an inlet flue of the high-temperature reheater, an outlet flue of the high-temperature reheater is connected with an inlet flue of the low-temperature superheater, an outlet flue of the low-temperature superheater is connected with an inlet flue of the low-temperature reheater, and an outlet flue of the low-temperature reheater is;

a hearth outlet section 13 is arranged at a hearth outlet of the boiler 1, a temporary thermocouple group 5 is arranged on the hearth outlet section 13, a smoke hole measuring group 11 is arranged above the hearth outlet section 13, the smoke hole measuring group 11 is positioned at the top of a horizontal flue, and the smoke hole measuring group 11 also penetrates through a small chamber 8 at the top of the boiler and is communicated with the flue at the hearth outlet section 13; the smoke measuring hole groups 11 are distributed along the outlet section 13 of the hearth from the left side of the hearth to the right side of the hearth at equal intervals, and the probes of the temporary thermocouple group 5 extend downwards from the top of the hearth to the actual measurement position 12 of the smoke temperature test of the outlet section 13 of the hearth through the smoke measuring hole groups 11; the non-probe end of the temporary thermocouple group 5 is connected with a data acquisition instrument 14.

2-4 thermocouples are inserted into each smoke measuring hole group 11.