Monitoring method and system for heat storage element of air pre-heater

Abstract

The invention relates to the field of air pre-heaters, and provides a monitoring method and system for a heat storage element of an air pre-heater, and the method comprises the steps: S1, controlling the air pre-heater to enter flue gas in the current period, and stopping entering air; acquiring flue gas parameters of a flue gas inlet and flue gas parameters of a flue gas outlet of the air pre-heater for multiple times in the current period, acquiring flow velocity of a flow velocity detection point on the flue gas side of a heat storage element of the air pre-heater for multiple times in the current period, and acquiring temperature of a temperature detection point on the surface of the flue gas side of the heat storage element of the air pre-heater for multiple times in the current period; s2, determining a first performance parameter of the heat storage element of the air pre-heater based on the step S1; and S3, when the first performance parameter of the heat storage element of the air pre-heater is not within the corresponding first preset range, a first alarm is given. The heat storage element of the air pre-heater does not need to be detached from the air pre-heater for detection, periodic online detection of the heat storage element of the air pre-heater is achieved (during online detection, smoke is firstly controlled to enter the air pre-heater in the current period, and air is stopped from entering the air pre-heater), and reliable use of the heat storage element of the air pre-heater is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of air preheaters, and in particular to a monitoring method and system for a heat storage element of an air preheater. Background Art

[0002] The air preheater is a heating surface where the flue gas in the tail flue of the boiler is preheated to a certain temperature before entering the boiler through the heat storage element inside the air preheater. It is a device used to improve the heat exchange performance of the boiler and reduce energy consumption. When it is working, the flue gas (waste gas) discharged by the boiler is introduced into the air preheater, and the heat in the flue gas will be absorbed and stored by the heat storage element. The cooled flue gas is discharged outside, and the external air enters the air preheater, where it will be preheated by the heat storage element and then sent into the boiler.

[0003] In the prior art, the heat exchange performance detection of the air preheater heat exchange element / heat storage element is usually performed offline when the heat exchange element / heat storage element is not installed on the air preheater (such as CN 209264263U), and it is impossible to realize online monitoring of the air preheater heat storage element. Summary of the invention

[0004] The present invention provides a monitoring method and system for an air preheater heat storage element, which are used to solve the technical problems of the prior art proposed by the above background technology.

[0005] In order to solve the above problems, the present invention discloses a monitoring method for an air preheater heat storage element, comprising:

[0006] Step S1: Control the flue gas intake of the air preheater in the current cycle and stop the intake of air; obtain the flue gas parameters of the flue gas inlet and the flue gas outlet of the air preheater multiple times in the current cycle, obtain the flow rate of the flow rate detection point on the flue gas side of the air preheater heat storage element multiple times in the current cycle, and obtain the temperature of the surface temperature detection point on the flue gas side of the air preheater heat storage element multiple times in the current cycle;

[0007] Step S2: determining a first performance parameter of the air preheater heat storage element based on step S1;

[0008] Step S3: When the first performance parameter of the air preheater heat storage element is not within the corresponding first preset range, a first alarm is issued.

[0009] Preferably, it also includes:

[0010] Step S4: in the next cycle, the air preheater is controlled to stop the intake of flue gas and to intake air, the air parameters of the air inlet and the air outlet of the air preheater are obtained, the flow velocity of the flow velocity detection point on the air side of the heat storage element of the air preheater is obtained multiple times in the next cycle, and the temperature of the surface temperature detection point on the air side of the heat storage element of the air preheater is obtained multiple times in the next cycle;

[0011] Step S5: determining a second performance parameter of the air preheater heat storage element based on step S4;

[0012] Step S6: When the second performance parameter of the air preheater heat storage element is not within the corresponding second preset range, a second alarm is issued.

[0013] Preferably, determining the first performance parameter of the air preheater heat storage element based on step S1 includes:

[0014] Step S21: constructing a first temperature change curve based on the temperature detection values ​​of the temperature detection points on the surface of the flue gas side of the air preheater heat storage element obtained multiple times in the current cycle, wherein the detection time in the first temperature change curve is the horizontal coordinate, and the average value of the temperature detection values ​​of all the temperature detection points on the surface of the flue gas side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0015] Based on the flow velocity detection values ​​of the flow velocity detection points on the flue gas side of the air preheater heat storage element obtained multiple times in the current cycle, a first flow velocity change curve is constructed, in which the detection time is the horizontal coordinate, and the average value of the flow velocity detection values ​​of all the flow velocity detection points on the flue gas side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0016] Step S22: dividing the first temperature change curve into a plurality of first sub-curve segments based on a preset time interval, and numbering each first sub-curve segment;

[0017] The first flow velocity variation curve is divided into a plurality of second sub-curve segments based on a preset time interval, and each second sub-curve segment is numbered; the detection time of the i-th first sub-curve segment corresponds to the i-th second sub-curve segment;

[0018] Step S23: Calculate the first performance parameter of the air preheater heat storage element based on the first sub-curve segment and the second sub-curve segment.

[0019] Preferably, the first performance parameter is calculated based on the following formula:

[0020]

[0021] K1 is the first performance evaluation parameter; C0 is the specific heat capacity of the flue gas in the air preheater in the current cycle; ρ0 is the density of the flue gas at the flue gas inlet of the air preheater in the current cycle; T 11 is the average detected value of the flue gas temperature at the flue gas inlet of the air preheater in the current cycle; T i10 is the average detected value of the temperature of the flue gas at the flue gas outlet of the air preheater during the detection period corresponding to the i-th first sub-curve segment; S1 is the heat exchange area between the air preheater heat storage element and the flue gas; T 2i1 is the maximum ordinate of the i-th first sub-curve segment; T 2i0is the minimum ordinate of the i-th first subcurve segment; β i The flue gas side of the air preheater heat storage element The corresponding theoretical heat transfer coefficient; v i is the average ordinate of the i-th second sub-curve segment; θ i is the average slope of the second sub-curve segment of the ith segment; δ(θ i ) is θ i The corresponding first correction coefficient; N2 is the total number of flow rate detection points on the flue gas side of the air preheater heat storage element in the current cycle; N i1 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the i-th second sub-curve segment is greater than v i Ni2 is the total number of velocity detection points; Ni2 is the average velocity detection value of the velocity detection point in the detection period corresponding to the i-th second sub-curve segment is less than v i The total number of flow rate detection points; for The corresponding second correction coefficient; ln is the natural logarithm, and e is the natural constant.

[0022] Preferably, determining the second performance parameter of the air preheater heat storage element based on step S4 includes:

[0023] Step S51: constructing a second temperature change curve based on the temperatures of the temperature detection points on the surface of the air side of the air preheater heat storage element obtained multiple times in the next cycle, wherein the detection time in the second temperature change curve is the horizontal coordinate, and the average value of the temperature detection values ​​of the temperature detection points on the surface of the air side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0024] Based on the flow velocities of the flow velocity detection points on the air side of the air preheater heat storage element obtained multiple times in the current cycle, a second flow velocity change curve is constructed, in which the detection time is the horizontal coordinate, and the average value of the flow velocity detection values ​​of the flow velocity detection points on the air side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0025] Step S52: dividing the second temperature change curve into a plurality of third sub-curve segments based on a preset time interval, and numbering each third sub-curve segment;

[0026] The second flow velocity variation curve is divided into a plurality of fourth sub-curve segments based on a preset time interval, and each fourth sub-curve segment is numbered; the detection time of the jth third sub-curve segment corresponds to the detection time of the jth fourth sub-curve segment;

[0027] Step S53: Calculate the second performance parameter of the air preheater heat storage element based on the third sub-curve segment and the fourth sub-curve segment.

[0028] Preferably, it also includes:

[0029] Step S7: determining a first time interval from the time the first performance parameter is acquired for the current time to the start of the step S1 for acquiring the first performance parameter next time based on the first performance parameter acquired for the current time, the first performance parameter acquired for the previous time, and the step S1 for acquiring the first performance parameter for the current time;

[0030] Step S8: Based on the second performance parameter currently acquired, the second performance parameter previously acquired, and step S4 of currently acquiring the second performance parameter, determine the second time interval and the final time interval from the current acquisition of the first performance parameter to the start of step S1 for the next acquisition of the first performance parameter; the first performance parameter is acquired the next time after the current acquisition of the first performance parameter at a corresponding final time interval.

[0031] Preferably, the first time interval is calculated based on the following formula:

[0032]

[0033] t r+1 K is the time interval from the time the first performance parameter is obtained for the rth time to the start of step S1 for obtaining the first performance parameter for the r+1th time; r1 is the first performance parameter obtained for the rth time; K (r-1)1 is the first performance parameter obtained for the r-1th time; K r1 -K (r-1)1 The corresponding reference time interval; v r v is the average value of the flow velocity at the flow velocity detection point on the flue gas side of the air preheater heat storage element obtained in step S1 of obtaining the first performance parameter for the rth time; r0 The average flue gas flow rate at the flue gas inlet of the air preheater obtained in step S1 of obtaining the first performance parameter for the rth time; h1 is the initial use of the heat storage element of the air preheater, Corresponding reference value; T r is the standard deviation of the temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element when the first performance parameter is obtained for the last time; T r0 is the average temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element obtained for the last time when the first performance parameter is obtained for the rth time;

[0034] The second time interval and the final time interval are calculated based on the following formula:

[0035]

[0036] W r+1 =min(t r+1 , H r+1 );

[0037] H r+1is the second time interval from the time when the first performance parameter is obtained for the rth time to the time when the step S1 for obtaining the first performance parameter for the r+1th time starts; K r2 is the second performance parameter obtained for the rth time; K (r-1)2 is the second performance parameter obtained for the r-1th time; ω(K r2 -K (r-1)2 ) is K r2 -K (r-1)2 The corresponding reference time interval; v r2 v is the average value of the flow velocity at the flow velocity detection point on the air side of the air preheater heat storage element obtained in step S4 of obtaining the second performance parameter for the rth time; r20 The average air flow rate of the air inlet of the air preheater obtained in step S4 of obtaining the second performance parameter for the rth time; h2 is the initial use of the heat storage element of the air preheater, Corresponding reference value; T r2 is the standard deviation of the temperature of the temperature detection point on the surface of the air side of the air preheater heat storage element when the second performance parameter is obtained for the last time; T r20 is the average temperature of the temperature detection point on the surface of the air side of the air preheater heat storage element obtained for the last time when the second performance parameter is obtained for the rth time; W r+1 It is the final time interval from the time when the first performance parameter is obtained for the rth time to the start of step S1 of obtaining the first performance parameter for the (r+1)th time; min represents the minimum value.

[0038] The present invention also provides a monitoring system for an air preheater heat storage element, comprising:

[0039] A first flue gas detection module, used for detecting flue gas parameters at the flue gas inlet of the air preheater;

[0040] The second flue gas detection module is used to detect the flue gas parameters at the flue gas outlet of the air preheater;

[0041] A first flow rate detection module, used to detect the flow rate of a flow rate detection point on the flue gas side of the air preheater heat storage element;

[0042] The temperature detection module is used to detect the temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element.

[0043] Compared with the prior art, the present invention has the following beneficial effects: controlling the current cycle of the air preheater to admit flue gas, stopping the admission of air, and obtaining the above parameters of the flue gas and the heat storage element, obtaining the first performance parameter of the air preheater heat storage element, the first performance parameter being the heat exchange performance parameter of the air preheater heat storage element with the flue gas; when the first performance parameter of the air preheater heat storage element is not within the corresponding first preset range, a first alarm is issued, so that when the heat exchange performance parameter of the air preheater heat storage element with the flue gas is abnormal, an alarm is issued in time to ensure the heat absorption effect of the air preheater heat storage element. Moreover, the present invention does not need to disassemble the heat storage element from the air preheater for detection, and is easy to operate, and can realize periodic online detection of the air preheater heat storage element (during online detection, first control the air preheater to admit flue gas in the current cycle and stop the admission of air), which is convenient for ensuring the reliable use of the air preheater heat storage element. .

[0044] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0046] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0048] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0050] The present invention provides the following embodiments

[0051] Embodiment 1, the present invention provides a method for monitoring the heat storage element of an air preheater, such as Figure 1 As shown, including:

[0052] Step S1: Control the air preheater to enter flue gas in the current cycle and stop entering air; obtain the flue gas parameters of the flue gas inlet and the flue gas outlet of the air preheater multiple times in the current cycle, obtain the flow rate of the flow rate detection point on the flue gas side of the air preheater heat storage element multiple times in the current cycle, and obtain the temperature of the surface temperature detection point on the flue gas side of the air preheater heat storage element multiple times in the current cycle; the above flow rate and temperature can be detected by setting corresponding sensors;

[0053] Step S2: determining a first performance parameter of the air preheater heat storage element based on step S1;

[0054] Step S3: When the first performance parameter of the air preheater heat storage element is not within the corresponding first preset range, a first alarm is issued.

[0055] The embodiment of the present invention further provides a monitoring system for an air preheater heat storage element, comprising:

[0056] A first flue gas detection module, used for detecting flue gas parameters at the flue gas inlet of the air preheater;

[0057] The second flue gas detection module is used to detect the flue gas parameters at the flue gas outlet of the air preheater;

[0058] A first flow rate detection module, used to detect the flow rate of a flow rate detection point on the flue gas side of the air preheater heat storage element;

[0059] The temperature detection module is used to detect the temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element.

[0060] The beneficial effects of the above technical solution are: controlling the air preheater to admit flue gas in the current cycle, stopping the admission of air, and obtaining the above parameters of the flue gas and the heat storage element, obtaining the first performance parameter of the air preheater heat storage element, the first performance parameter being the heat exchange performance parameter of the air preheater heat storage element with the flue gas; when the first performance parameter of the air preheater heat storage element is not within the corresponding first preset range, a first alarm is issued, so that when the heat exchange performance parameter of the air preheater heat storage element with the flue gas is abnormal, a timely alarm is issued to ensure the heat absorption effect of the air preheater heat storage element. In addition, the present invention does not require the removal of the heat storage element from the air preheater for detection, is easy to operate, and can realize periodic online detection of the air preheater heat storage element (during online detection, first control the air preheater to admit flue gas in the current cycle and stop the admission of air), which is convenient for ensuring the reliable use of the air preheater heat storage element.

[0061] Embodiment 2, based on embodiment 1, further comprises:

[0062] Step S4: in the next cycle, the air preheater is controlled to stop the intake of flue gas and to control the intake of air, and the air parameters of the air inlet and the air outlet of the air preheater are obtained in the next cycle. The flow velocity of the flow velocity detection point on the air side of the air preheater heat storage element is obtained multiple times in the next cycle, and the temperature of the surface temperature detection point on the air side of the air preheater heat storage element is obtained multiple times in the next cycle. For the rotational transformation of the heat storage element at the flue gas and the air, Embodiment 2 first makes the heat storage element at the flue gas, and then rotates the heat storage element after absorbing heat to the air. At this time, the flow velocity detection point and the temperature detection point of Embodiment 1 and Embodiment 2 can be the same;

[0063] Step S5: determining a second performance parameter of the air preheater heat storage element based on step S4;

[0064] Step S6: When the second performance parameter of the air preheater heat storage element is not within the corresponding second preset range, a second alarm is issued.

[0065] The beneficial effects of the above technical solution are: in the next cycle, the air preheater is controlled to stop the intake of flue gas and to control the intake of air, and the above parameters of the heat storage element and the air are obtained to obtain the second performance parameter of the air preheater heat storage element, the second performance parameter is the heat exchange performance parameter of the air preheater heat storage element with the air, and when the second performance parameter of the air preheater heat storage element is not within the corresponding second preset range, a second alarm is issued to achieve timely alarm when the heat exchange performance parameter of the air preheater heat storage element with the air is abnormal, thereby ensuring the heat release effect of the air preheater heat storage element on the air.

[0066] Embodiment 3, based on Embodiment 1 or 2, determining the first performance parameter of the air preheater heat storage element based on step S1 includes:

[0067] Step S21: constructing a first temperature change curve based on the temperature detection values ​​of the temperature detection points on the surface of the flue gas side of the air preheater heat storage element obtained multiple times in the current cycle, wherein the detection time in the first temperature change curve is the horizontal coordinate, and the average value of the temperature detection values ​​of all the temperature detection points on the surface of the flue gas side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0068] Based on the flow velocity detection values ​​of the flow velocity detection points on the flue gas side of the air preheater heat storage element obtained multiple times in the current cycle, a first flow velocity change curve is constructed, in which the detection time is the horizontal coordinate, and the average value of the flow velocity detection values ​​of all the flow velocity detection points on the flue gas side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0069] Step S22: dividing the first temperature change curve into a plurality of first sub-curve segments based on a preset time interval, and numbering each first sub-curve segment;

[0070] The first flow velocity variation curve is divided into a plurality of second sub-curve segments based on a preset time interval, and each second sub-curve segment is numbered; the detection time of the i-th first sub-curve segment corresponds to the i-th second sub-curve segment;

[0071] Step S23: Calculate the first performance parameter of the air preheater heat storage element based on the first sub-curve segment and the second sub-curve segment.

[0072] Preferably, the first performance parameter is calculated based on the following formula:

[0073]

[0074] K1 is the first performance evaluation parameter; C0 is the specific heat capacity of the flue gas in the air preheater in the current cycle; ρ0 is the density of the flue gas at the flue gas inlet of the air preheater in the current cycle; T 11 is the average detected value of the flue gas temperature at the flue gas inlet of the air preheater in the current cycle; T i10 is the average detected value of the temperature of the flue gas at the flue gas outlet of the air preheater during the detection period corresponding to the i-th first sub-curve segment; S1 is the heat exchange area between the air preheater heat storage element and the flue gas; T 2i1 is the maximum ordinate of the i-th first sub-curve segment; T 2i0 is the minimum ordinate of the i-th first subcurve segment; β i The flue gas side of the air preheater heat storage element The corresponding theoretical heat transfer coefficient; v i is the average ordinate of the i-th second sub-curve segment; θ i is the average slope of the second sub-curve segment of the ith segment; δ(θ i ) is θ i The corresponding first correction coefficient (which can be obtained based on a preset mapping table or calculated based on the following formula) π is taken as 3.14); N2 is the total number of flow rate detection points on the flue gas side of the air preheater heat storage element in the current cycle; N i1 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the i-th second sub-curve segment is greater than v i The total number of flow rate detection points; N i2 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the i-th second sub-curve segment is less than v i The total number of flow rate detection points; for The corresponding second correction coefficient (which can be obtained based on a preset mapping table or calculated based on the following formula) ln is the natural logarithm, and e is a natural constant.

[0075] The beneficial effects of the above technical solution are as follows: since there is a relationship between the heat transfer coefficient and the temperature difference, this embodiment divides the current cycle according to preset time intervals, and obtains the flue gas parameters corresponding to each detection period (the average detection value of the temperature of the flue gas at the flue gas inlet, the average detection value of the temperature of the flue gas at the flue gas outlet of the air preheater in each detection period, the specific heat capacity of the flue gas in the air preheater in the current period, the density of the flue gas at the flue gas inlet of the air preheater in the current period, and the average value of the flow rate detection values ​​of all flow rate detection points on the flue gas side in each detection period) and the parameters of the air preheater heat storage element (the heat exchange area of ​​the air preheater heat storage element with the flue gas, the average value of the temperature detection values ​​of all temperature detection points on the surface of the flue gas side of the air preheater heat storage element in each detection period), and the correction coefficient Calculate the actual heat transfer coefficient of the flue gas side of the air preheater heat storage element corresponding to the detection period The calculation is reliable; and the theoretical heat transfer coefficient β corresponding to the temperature difference state of the corresponding detection period i The first performance evaluation parameter is obtained by comparison, and the calculation is reliable, so that a reliable evaluation of the heat absorption effect of the air preheater heat storage element of the present invention can be achieved.

[0076] Embodiment 4, based on embodiment 2, determines the second performance parameter of the air preheater heat storage element based on step S4, including:

[0077] Step S51: constructing a second temperature change curve based on the temperatures of the temperature detection points on the surface of the air side of the air preheater heat storage element obtained multiple times in the next cycle, wherein the detection time in the second temperature change curve is the horizontal coordinate, and the average value of the temperature detection values ​​of the temperature detection points on the surface of the air side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0078] Based on the flow velocities of the flow velocity detection points on the air side of the air preheater heat storage element obtained multiple times in the current cycle, a second flow velocity change curve is constructed, in which the detection time is the horizontal coordinate, and the average value of the flow velocity detection values ​​of the flow velocity detection points on the air side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate;

[0079] Step S52: dividing the second temperature change curve into a plurality of third sub-curve segments based on a preset time interval, and numbering each third sub-curve segment;

[0080] The second flow velocity variation curve is divided into a plurality of fourth sub-curve segments based on a preset time interval, and each fourth sub-curve segment is numbered; the detection time of the jth third sub-curve segment corresponds to the detection time of the jth fourth sub-curve segment;

[0081] Step S53: Calculate the second performance parameter of the air preheater heat storage element based on the third sub-curve segment and the fourth sub-curve segment.

[0082] Preferably, the second performance parameter is calculated based on the following formula:

[0083]

[0084] K2 is the second performance evaluation parameter; T 3j2 is the maximum ordinate of the jth third sub-curve segment; T 3j0 is the minimum ordinate of the jth third sub-curve segment; S2 is the heat exchange area between the air preheater heat storage element and the air; C1 is the specific heat capacity of the air; ρ1 is the air density at the air inlet of the air preheater in the next cycle; T 3j1 is the average value of the temperature detection value of the air outlet of the air preheater in the detection period corresponding to the jth third sub-curve segment; T 30 is the average value of the temperature detection value of the air inlet of the air preheater in the next cycle; v j1 is the average ordinate of the jth fourth sub-curve segment; n j1 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the jth fourth sub-curve segment is greater than v j1 The total number of flow rate detection points; n j2 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the jth fourth sub-curve segment is less than v j1 n2 is the total number of flow rate detection points on the air side of the air preheater heat storage element in the next cycle; for The corresponding fourth correction coefficient (which can be obtained based on a preset mapping table or calculated based on the following formula) is the average slope of the jth fourth sub-curve segment; for The corresponding third correction coefficient (which can be obtained based on a preset mapping table or calculated based on the following formula) π is 3.14); ln is the natural logarithm, e is the natural constant; σ j The flue gas side of the air preheater heat storage element The corresponding theoretical heat transfer coefficient.

[0085] The beneficial effects of the above technical solution are:

[0086] Since the heat exchange coefficient is related to the temperature difference, this embodiment divides the next cycle into preset time intervals, and obtains the air parameters corresponding to each detection period (the average value of the temperature detection value of the air inlet of the air preheater in the next cycle, the average value of the temperature detection value of the air outlet of the air preheater in each detection period, the specific heat capacity of the air of the air preheater in the current cycle, the air density of the air inlet of the air preheater in the next cycle, and the average value of the flow rate detection values ​​of all flow rate detection points on the air side in each detection period) and the parameters of the air preheater heat storage element (the heat exchange area of ​​the air preheater heat storage element with the air, the average value of the temperature detection values ​​of all temperature detection points on the surface of the air side of the air preheater heat storage element in each detection period), and the correction coefficient Calculate the actual heat transfer coefficient of the air side of the air preheater heat storage element corresponding to the detection period The calculation is reliable; and the theoretical heat transfer coefficient σ corresponding to the temperature difference state of the corresponding detection period j The second performance evaluation parameter is obtained by comparison, and the calculation is reliable, so that a reliable evaluation of the heat absorption effect of the air preheater heat storage element of the present invention can be achieved.

[0087] Embodiment 5, based on any one of Embodiments 2-4, further comprises:

[0088] Step S7: determining a first time interval from the time the first performance parameter is acquired for the current time to the start of the step S1 for acquiring the first performance parameter next time based on the first performance parameter acquired for the current time, the first performance parameter acquired for the previous time, and the step S1 for acquiring the first performance parameter for the current time;

[0089] Step S8: Based on the second performance parameter currently acquired, the second performance parameter previously acquired, and step S4 of currently acquiring the second performance parameter, determine the second time interval and the final time interval from the current acquisition of the first performance parameter to the start of step S1 for the next acquisition of the first performance parameter; the first performance parameter is acquired the next time after the current acquisition of the first performance parameter at a corresponding final time interval.

[0090] The first time interval is calculated based on the following formula:

[0091]

[0092] t r+1 K is the time interval from the time the first performance parameter is obtained for the rth time to the start of step S1 for obtaining the first performance parameter for the r+1th time; r1 is the first performance parameter obtained for the rth time; K (r-1)1 is the first performance parameter obtained for the r-1th time; K r1 -K (r-1)1 The corresponding reference time interval (based on the preset (K r1 -K(r-1)1 )-reference time interval mapping table acquisition); v r v is the average value of the flow velocity at the flow velocity detection point on the flue gas side of the air preheater heat storage element obtained in step S1 of obtaining the first performance parameter for the rth time; r0 The average flue gas flow rate at the flue gas inlet of the air preheater obtained in step S1 of obtaining the first performance parameter for the rth time; h1 is the initial use of the heat storage element of the air preheater, Corresponding reference value; T r is the standard deviation of the temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element when the first performance parameter is obtained for the last time; T r0 is the average temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element obtained for the last time when the first performance parameter is obtained for the rth time;

[0093] The second time interval and the final time interval are calculated based on the following formula:

[0094]

[0095] W r+1 =min(t r+1 , H r+1 );

[0096] H r+1 is the second time interval from the time when the first performance parameter is obtained for the rth time to the time when the step S1 for obtaining the first performance parameter for the r+1th time starts; K r2 is the second performance parameter obtained for the rth time; K (r-1)2 is the second performance parameter obtained for the r-1th time; β(K r2 -K (r-1)2 ) is K r2 -K (r-1)2 The corresponding benchmark time interval (based on the preset K r2 -K (r-1)2 -reference time interval mapping table acquisition); v r2 v is the average value of the flow velocity at the flow velocity detection point on the air side of the air preheater heat storage element obtained in step S4 of obtaining the second performance parameter for the rth time; r20 is the average air flow rate of the air inlet of the air preheater obtained in step S4 of obtaining the second performance parameter for the rth time; h2 is the initial use of the heat storage element of the air preheater, Corresponding reference value; T r2 is the standard deviation of the temperature of the temperature detection point on the surface of the air side of the air preheater heat storage element when the second performance parameter is obtained for the last time; T r20 is the average temperature of the temperature detection point on the surface of the air side of the air preheater heat storage element obtained for the last time when the second performance parameter is obtained for the rth time; W r+1It is the final time interval from the time when the first performance parameter is obtained for the rth time to the start of step S1 of obtaining the first performance parameter for the (r+1)th time; min represents the minimum value.

[0097] The beneficial effects of the above technical solution are:

[0098] Based on the first performance parameter currently acquired, the first performance parameter previously acquired, and the step S1 of currently acquiring the first performance parameter, determine the first time interval from the time the first performance parameter is currently acquired to the start of the step S1 of next acquiring the first performance parameter (to achieve the change state K of the current first performance parameter according to the current first performance parameter) r1 -K (r-1)1 Get the initial time interval Then, based on the actual flow rate state and temperature state in the current process of obtaining the first performance, the initial actual interval is corrected. obtain the final performance change state of the heat exchange element of the air preheater and the actual temperature state and flow rate state of the current cycle); based on the second performance parameter currently obtained, the second performance parameter previously obtained, and the step S4 of the second performance parameter currently obtained, determine the second time interval from the current acquisition of the first performance parameter to the start of the step S1 of the next acquisition of the first performance parameter (to achieve the change state K of the current second performance parameter according to the current second performance parameter r2 -K (r-1)2 Get the initial time interval ω(K r2 -K (r-1)2 ), and then the initial time interval is corrected based on the actual flow rate state and temperature state during the current acquisition of the second performance parameter The final second time interval that matches the current second performance parameter change state of the heat exchange element of the air preheater and the actual temperature state and flow rate state of the next cycle is obtained, and the smaller of the first time interval and the second time interval is selected as the final time interval. After the first performance parameter is obtained for the first time, the first performance parameter is obtained for the next time at the corresponding final time interval, ensuring that a suitable final time interval is selected for the next performance test.

[0099] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for monitoring an air preheater heat storage element, characterized in that: include: Step S1: Control the air preheater to allow flue gas to enter the current cycle and stop allowing air to enter; In the current cycle, the flue gas parameters of the flue gas inlet and the flue gas outlet of the air preheater are obtained multiple times, the flow rate of the flow rate detection point on the flue gas side of the air preheater heat storage element is obtained multiple times, and the temperature of the surface temperature detection point on the flue gas side of the air preheater heat storage element is obtained multiple times in the current cycle; Step S2: determining a first performance parameter of the air preheater heat storage element based on step S1; Step S3: When the first performance parameter of the air preheater heat storage element is not within the corresponding first preset range, a first alarm is issued.

2. The method for monitoring the heat storage element of an air preheater according to claim 1, characterized in that: Also includes: Step S4: in the next cycle, the air preheater is controlled to stop the intake of flue gas and to intake air, the air parameters of the air inlet and the air outlet of the air preheater are obtained, the flow velocity of the flow velocity detection point on the air side of the heat storage element of the air preheater is obtained multiple times in the next cycle, and the temperature of the surface temperature detection point on the air side of the heat storage element of the air preheater is obtained multiple times in the next cycle; Step S5: determining a second performance parameter of the air preheater heat storage element based on step S4; Step S6: When the second performance parameter of the air preheater heat storage element is not within the corresponding second preset range, a second alarm is issued.

3. The method for monitoring the heat storage element of an air preheater according to claim 1, characterized in that: Determining the first performance parameter of the air preheater heat storage element based on step S1 includes: Step S21: constructing a first temperature change curve based on the temperature detection values ​​of the temperature detection points on the surface of the flue gas side of the air preheater heat storage element obtained multiple times in the current cycle, wherein the detection time in the first temperature change curve is the horizontal coordinate, and the average value of the temperature detection values ​​of all the temperature detection points on the surface of the flue gas side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate; Based on the flow velocity detection values ​​of the flow velocity detection points on the flue gas side of the air preheater heat storage element obtained multiple times in the current cycle, a first flow velocity change curve is constructed, in which the detection time is the horizontal coordinate, and the average value of the flow velocity detection values ​​of all the flow velocity detection points on the flue gas side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate; Step S22: dividing the first temperature change curve into a plurality of first sub-curve segments based on a preset time interval, and numbering each first sub-curve segment; The first flow velocity variation curve is divided into a plurality of second sub-curve segments based on a preset time interval, and each second sub-curve segment is numbered; the detection time of the i-th first sub-curve segment corresponds to the i-th second sub-curve segment; Step S23: Calculate the first performance parameter of the air preheater heat storage element based on the first sub-curve segment and the second sub-curve segment.

4. The method for monitoring the heat storage element of an air preheater according to claim 3, characterized in that: The first performance parameter is calculated based on the following formula: K1 is the first performance evaluation parameter; C0 is the specific heat capacity of the flue gas in the air preheater in the current cycle; ρ0 is the density of flue gas at the flue gas inlet of the air preheater in the current cycle; T 11 is the average detected value of the flue gas temperature at the flue gas inlet of the air preheater in the current cycle; T i10 is the average detected value of the temperature of the flue gas at the flue gas outlet of the air preheater during the detection period corresponding to the i-th first sub-curve segment; S1 is the heat exchange area between the air preheater heat storage element and the flue gas; T 2i1 is the maximum ordinate of the i-th first sub-curve segment; T 2i0 is the minimum ordinate of the i-th first sub-curve segment; θ i The flue gas side of the air preheater heat storage element The corresponding theoretical heat transfer coefficient; v i is the average ordinate of the i-th second sub-curve segment; θ i is the average slope of the second sub-curve segment of the ith segment; δ(θ i ) is θ i The corresponding first correction coefficient; N2 is the total number of flow rate detection points on the flue gas side of the air preheater heat storage element in the current cycle; N i1 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the i-th second sub-curve segment is greater than v i The total number of flow rate detection points; N i2 The average flow velocity detection value of the flow velocity detection point in the detection period corresponding to the i-th second sub-curve segment is less than v i The total number of flow rate detection points; for The corresponding second correction coefficient; ln is the natural logarithm, and e is the natural constant.

5. The method for monitoring the heat storage element of an air preheater according to claim 2, characterized in that: Determining the second performance parameter of the air preheater heat storage element based on step S4 includes: Step S51: constructing a second temperature change curve based on the temperatures of the temperature detection points on the surface of the air side of the air preheater heat storage element obtained multiple times in the next cycle, wherein the detection time in the second temperature change curve is the horizontal coordinate, and the average value of the temperature detection values ​​of the temperature detection points on the surface of the air side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate; Based on the flow velocities of the flow velocity detection points on the air side of the air preheater heat storage element obtained multiple times in the current cycle, a second flow velocity change curve is constructed, in which the detection time is the horizontal coordinate, and the average value of the flow velocity detection values ​​of the flow velocity detection points on the air side of the air preheater heat storage element corresponding to the detection time is the vertical coordinate; Step S52: dividing the second temperature change curve into a plurality of third sub-curve segments based on a preset time interval, and numbering each third sub-curve segment; The second flow velocity variation curve is divided into a plurality of fourth sub-curve segments based on a preset time interval, and each fourth sub-curve segment is numbered; the detection time of the jth third sub-curve segment corresponds to the detection time of the jth fourth sub-curve segment; Step S53: Calculate the second performance parameter of the air preheater heat storage element based on the third sub-curve segment and the fourth sub-curve segment.

6. The method for monitoring the heat storage element of an air preheater according to claim 2, characterized in that: Also includes: Step S7: determining a first time interval from the time the first performance parameter is acquired for the current time to the start of the step S1 for acquiring the first performance parameter next time based on the first performance parameter acquired for the current time, the first performance parameter acquired for the previous time, and the step S1 for acquiring the first performance parameter for the current time; Step S8: Based on the second performance parameter currently acquired, the second performance parameter previously acquired, and step S4 of currently acquiring the second performance parameter, determine the second time interval and the final time interval from the current acquisition of the first performance parameter to the start of step S1 for the next acquisition of the first performance parameter; the first performance parameter is acquired the next time after the current acquisition of the first performance parameter at a corresponding final time interval.

7. The method for monitoring the heat storage element of an air preheater according to claim 6, characterized in that: The first time interval is calculated based on the following formula: t r+1 K is the time interval from the time the first performance parameter is obtained for the rth time to the start of step S1 for obtaining the first performance parameter for the r+1th time; r1 is the first performance parameter obtained for the rth time; K (r-1)1 is the first performance parameter obtained for the r-1th time; K r1 -K (r-1)1 The corresponding reference time interval; v r v is the average value of the flow velocity at the flow velocity detection point on the flue gas side of the air preheater heat storage element obtained in step S1 of obtaining the first performance parameter for the rth time; r0 The average flue gas flow rate at the flue gas inlet of the air preheater obtained in step S1 of obtaining the first performance parameter for the rth time; h1 is the initial use of the heat storage element of the air preheater, Corresponding reference value; T r is the standard deviation of the temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element obtained for the last time when the first performance parameter is obtained for the rth time; T r0 is the average temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element obtained for the last time when the first performance parameter is obtained for the rth time; The second time interval and the final time interval are calculated based on the following formula: W r+1 =min(t r+1 ,H r+1 ); H r+1 is the second time interval from the time when the first performance parameter is obtained for the rth time to the time when the step S1 for obtaining the first performance parameter for the r+1th time starts; K r2 is the second performance parameter obtained for the rth time; K (r-1)2 is the second performance parameter obtained for the r-1th time; ω(K r2 -K (r-1)2 ) is K r2 -K (r-1)2 The corresponding reference time interval; v r2 v is the average value of the flow velocity at the flow velocity detection point on the air side of the air preheater heat storage element obtained in step S4 of obtaining the second performance parameter for the rth time; r20 The average air flow rate of the air inlet of the air preheater obtained in step S4 of obtaining the second performance parameter for the rth time; h2 is the initial use of the heat storage element of the air preheater, Corresponding reference value; T r2 is the standard deviation of the temperature of the temperature detection point on the surface of the air side of the air preheater heat storage element when the second performance parameter is obtained for the last time; T r20 is the average temperature of the temperature detection point on the surface of the air side of the air preheater heat storage element obtained for the last time when the second performance parameter is obtained for the rth time; W r+1 It is the final time interval from the time when the first performance parameter is obtained for the rth time to the start of step S1 of obtaining the first performance parameter for the (r+1)th time; min represents the minimum value.

8. A monitoring system for air preheater heat storage elements, characterized in that: include: A first flue gas detection module, used for detecting flue gas parameters at the flue gas inlet of the air preheater; The second flue gas detection module is used to detect the flue gas parameters at the flue gas outlet of the air preheater; A first flow rate detection module, used to detect the flow rate of a flow rate detection point on the flue gas side of the air preheater heat storage element; The temperature detection module is used to detect the temperature of the temperature detection point on the surface of the flue gas side of the air preheater heat storage element.

Images