Air leakage amount calculation method and system for quartered rotary air pre-heater

Abstract

The invention relates to a method and a system for calculating the air leakage rate of a quartered rotary air preheater. The method comprises the following steps of: obtaining related data of primary air, secondary air and a flue gas bin of the quartered rotary air preheater through calibration and online measurement; the air leakage amount of the quartered rotary air pre-heater is calculated on line according to the related data, wherein the air leakage amount comprises the primary air leakage amount, the air leakage amount of secondary air leaked into the left side and the right side of the primary air and the air leakage amount of a smoke bin; based on the primary air inlet flow and the primary air outlet flow, the primary air leakage amount is obtained; based on the pressure difference of the primary air to the left side and the right side of the secondary air of the air pre-heater, the air leakage amount of the primary air leaking into the left side and the right side of the secondary air is calculated; secondary air inlet flow and secondary air outlet flow are calculated based on the secondary air bifurcated pipe; and calculating the air leakage amount of the secondary air leaked into the flue gas bin at the left and right sides of the air pre-heater by utilizing the primary air, the secondary air and the inlet and outlet flow of the flue gas bin, namely the air leakage amount of the flue gas bin.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of air preheater leakage calculation, and particularly relates to a four-division rotary air preheater leakage calculation method and system. BACKGROUND

[0002] The rotary air preheater (hereinafter referred to as "air preheater") is a key heating surface equipment of the boiler tail flue of a power plant, and its core function is to preheat the air before the operation of the boiler to a specific temperature through the internal heat radiating fins, so as to reduce energy consumption and improve the thermal efficiency of the boiler. In the long-term operation process of the boiler system, the sealing structure of the air preheater will gradually fail due to factors such as wear and thermal deformation, resulting in continuous increase of the air preheater leakage. This air leakage phenomenon is specifically manifested as leakage of the primary air and the secondary air to the flue gas chamber, which not only directly affects the combustion efficiency of the boiler, but also poses a serious threat to the safe and economic operation of the entire unit.

[0003] However, the online measurement of the secondary air leakage of the air preheater in the prior art cannot effectively solve the following problems: first, the non-uniformity of the pressure field affects the measurement, when the air preheater is running, the pressure field in the air preheater along the circumferential direction is often in a non-uniform state, resulting in periodic fluctuation of the inlet and outlet pressures of the secondary air on the left and right sides, and the traditional measurement method based on the assumption of uniform pressure field is invalid; second, the flow calculation model is not perfect, the prior art lacks accurate description of the dynamic relationship between the secondary air inlet flow, outlet flow and pressure difference, and it is difficult to establish a flow calculation model that adapts to complex working conditions; third, the adaptability of the measurement device is insufficient, the measurement accuracy of the conventional flow measurement device is greatly reduced when installed in special positions such as a curved pipe and a short straight pipe section, and it cannot be calibrated in real time in response to the dynamic changes of the flow on the left and right sides of the air preheater.

[0004] In addition, the existing leakage calculation methods are mostly single parameter measurement or independent module calculation, lacking systematic integration of the primary air, secondary air and flue gas chamber data, and it is difficult to realize online real-time calculation and early warning of the leakage, and it cannot provide effective data support for the optimized operation and accurate maintenance of the boiler.

[0005] In summary, there is an urgent need for a method that can accurately and online calculate the leakage of the four-division rotary air preheater, to solve the problems of online measurement of secondary air leakage, large calculation error of flue gas leakage, non-uniformity of pressure field affecting measurement accuracy, and insufficient system integration and real-time performance in the prior art, so as to realize dynamic monitoring of the air preheater leakage, and provide a reliable basis for the safe and economic operation and maintenance decision of the boiler unit. SUMMARY

[0006] In order to solve the above problems existing in the prior art, the present application provides a four-division rotary air preheater leakage calculation method and system.

[0007] The technical scheme of the present application is as follows:

[0008] In one aspect, the application provides a method for calculating the air leakage of a four-bin rotary air preheater, the method comprising:

[0009] Obtaining relevant data of the primary air, secondary air and flue gas bin of the four-bin rotary air preheater through calibration and online measurement; calculating the air leakage of the four-bin rotary air preheater online according to the relevant data, wherein the air leakage includes the primary air leakage, the leakage of the primary air into the secondary air on the left and right sides, and the leakage of the flue gas bin;

[0010] Based on the primary air inlet flow and the primary air outlet flow, the primary air leakage is obtained;

[0011] Based on the pressure difference of the primary air on the left and right sides of the secondary air of the air preheater, the leakage of the primary air into the secondary air on the left and right sides is calculated;

[0012] The secondary air inlet flow and the secondary air outlet flow are calculated based on the secondary air bifurcated pipe;

[0013] The leakage of the secondary air on the left and right sides of the air preheater into the flue gas bin, i.e. the leakage of the flue gas bin, is calculated using the inlet and outlet flow of the primary air, secondary air and flue gas bin.

[0014] Preferably, the calculation step of the pressure difference of the primary air on the left and right sides of the secondary air of the air preheater is specifically:

[0015] Based on the inlet and outlet pressures of the primary air, secondary air and secondary air on the left and right sides of the air preheater, the average pressure difference of the primary air on the left and right sides of the secondary air is calculated;

[0016] Based on the average pressure difference of the primary air on the left and right sides of the secondary air, the leakage of the primary air to the secondary air is calculated.

[0017] Preferably, the secondary air inlet flow includes the flow through the air preheater manifold to the left bifurcated pipe and the right bifurcated pipe, and specifically:

[0018] The pressure relationship between the air preheater manifold and the left bifurcated pipe is expressed in the formula as:

[0019] p sinl =p sfout -k sin ·(f sin ) 2 -k sinl ·(f sinl ) 2 ;

[0020] In the formula, p sfout represents the pressure at the outlet of the air blower; k sin represents the flow pressure coefficient of the secondary air at the inlet of the air preheater manifold; f sinrepresents the secondary air flow at the inlet of the left side bifurcated pipe, i.e. the left side secondary air flow; k sinl represents the flow pressure coefficient of the secondary air at the inlet of the left side bifurcated pipe; p sinl represents the secondary air pressure at the inlet of the left side bifurcated pipe; f sinl represents the secondary air flow at the inlet of the left side bifurcated pipe, i.e. the left side secondary air flow; k

[0021] represents the pressure relationship between the air preheater manifold and the right side bifurcated pipe, which is expressed by the formula:

[0022] p sinr = p sfout -k sin · (f sin ) 2 -k sinr · (f sinr ) 2 ;

[0023] In the formula, k sinr represents the flow pressure coefficient of the secondary air at the inlet of the right side bifurcated pipe; p sinr represents the secondary air pressure at the inlet of the right side bifurcated pipe; f sinr represents the secondary air flow at the inlet of the right side bifurcated pipe, i.e. the right side secondary air flow.

[0024] Preferably, the obtaining step of the secondary air flow at the inlet of the left side bifurcated pipe and the right side bifurcated pipe of the air preheater is specifically as follows:

[0025] If the pressure is uneven in the circumferential direction of the air preheater, the pressure at the secondary air inlets of the left and right sides of the air preheater will periodically change, and the expressions of the secondary air inlet flow and the secondary air inlet pressure of the left and right sides are obtained;

[0026] The relationship between the flow pressure coefficients of the secondary air of the left and right sides is judged, and if the difference between the flow pressure coefficients of the secondary air of the left and right sides is in a preset interval, it is indicated that the flow pressure coefficient of the left side is equal to the flow pressure coefficient of the right side;

[0027] The flow pressure coefficients of the secondary air of the left and right sides are substituted into the expressions, and the secondary air inlet flow of the right side is equal to the secondary air inlet flow of the left side.

[0028] Preferably, the obtaining step of the secondary air flow at the inlet of the left side bifurcated pipe and the right side bifurcated pipe of the air preheater is specifically as follows:

[0029] When the pressure of the air preheater is uniform in the circumferential direction, the pressures at the outlets of the left and right sides of the air preheater are the same, and the left side secondary air outlet flow is equal to the right side secondary air outlet flow.

[0030] Preferably, the obtaining step of the secondary air flow at the inlet of the left side bifurcated pipe and the right side bifurcated pipe of the air preheater is specifically as follows:

[0031] If the pressure is uneven in the circumferential direction of the air preheater, the pressure at the left and right outlet of the air preheater will periodically change, and the expressions of the left secondary air outlet flow and the right secondary air outlet flow are obtained;

[0032] The pressure drop of the secondary air at the left and right outlet is calculated respectively, and substituted into the expressions to obtain the left and right secondary air outlet flow.

[0033] Preferably, the calculation step of the flue gas leakage amount is specifically:

[0034] The flue gas data is obtained by using the flow meter of the flue gas online monitoring system;

[0035] Based on the flue gas data, the oxygen content, flow and pressure at the inlet and outlet of the left and right flue gas chambers are calculated;

[0036] Based on the oxygen content at the inlet and outlet of the left and right flue gas chambers, the flue gas leakage amount of the secondary air leaking into the flue gas chamber, i.e. the flue gas leakage amount of the flue gas chamber, is calculated, which is expressed by the formula:

[0037] f g =f sgl +f sgr ;

[0038] In the formula, f g represents the flue gas leakage amount; f sgl represents the flue gas leakage amount of the left secondary air leaking into the flue gas chamber; and f sgr represents the flue gas leakage amount of the right secondary air leaking into the flue gas chamber.

[0039] Preferably, the calculation step of the flue gas leakage amount is specifically:

[0040] A plurality of calibration points are arranged in the left and right flue gas chambers, and at least one measuring point is taken at each calibration point;

[0041] The pressure difference at the inlet and outlet of the left and right flue gas chambers in the current period is collected by the measuring point;

[0042] The function relationship between the pressure difference of the left and right flue gas chambers and the preset working condition coefficient is fitted by using the regression method, and the inlet and outlet flow of the left and right flue gas chambers is obtained;

[0043] The inlet and outlet flow of the flue gas chamber is calculated based on the inlet and outlet flow of the left and right flue gas chambers;

[0044] The flue gas leakage amount of the flue gas chamber is obtained based on the inlet and outlet flow of the flue gas chamber, which is expressed by the formula:

[0045] f g =f gout -f gin ;

[0046] In the formula, f gf gout f gin f

[0047] Preferably, the calculation step of the flue gas chamber air leakage amount is specifically:

[0048] The flue gas chamber air leakage amount is generated by the secondary air leakage into the flue gas chamber, that is, the secondary air leakage amount is equal to the flue gas chamber air leakage amount;

[0049] The flue gas chamber air leakage amount is obtained based on the secondary air leakage amount, which is expressed by the formula:

[0050] f s f sin f sout f sinl f soutl f sinr f soutr f g f p ;

[0051] In the formula, f s f sin f sout f sinl f sinr f soutl f soutr f g f p f

[0052] In another aspect, the present application also provides a flue gas chamber air leakage amount calculation system of a four-part chamber rotary air preheater, which comprises a data acquisition module and an air leakage amount calculation module:

[0053] The data acquisition module is used to obtain the relevant data of the primary air, the secondary air and the flue gas chamber of the four-part chamber rotary air preheater through calibration and online measurement; and the relevant data is transmitted to the air leakage amount calculation module;

[0054] The air leakage amount calculation module is used to calculate the air leakage amount of the four-part chamber rotary air preheater online according to the relevant data, wherein the air leakage amount includes the primary air leakage amount, the primary air leakage amount into the left and right secondary air, and the flue gas chamber air leakage amount;

[0055] The primary air leakage amount is obtained based on the primary air inlet flow and the primary air outlet flow;

[0056] Based on the pressure difference of the primary air on the left and right sides of the secondary air of the air preheater, the air leakage amount of the primary air into the left and right sides of the secondary air is calculated.

[0057] Based on the secondary air bifurcated pipe, the secondary air inlet flow and the secondary air outlet flow are calculated.

[0058] By using the primary air, the secondary air and the flue gas bin inlet and outlet flow, the air leakage amount of the secondary air into the flue gas bin on the left and right sides of the air preheater, i.e. the flue gas bin air leakage amount, is calculated.

[0059] Compared with the prior art, the beneficial effects of the present application are:

[0060] 1) The present application provides a four-warehouse rotary air preheater air leakage amount calculation method and system, which splits the air leakage path of the four-warehouse air preheater into primary air leakage, secondary air leakage and flue gas bin leakage, establishes a warehouse air leakage calculation method by online acquisition of warehouse inlet and outlet flow, pressure, oxygen content and other data; accurately distinguishes the air leakage contribution of different warehouses, breaks the traditional "total air leakage amount estimation" extensive mode, realizes the fine positioning of air leakage source, and improves the air leakage amount calculation precision;

[0061] 2) The present application provides a four-warehouse rotary air preheater air leakage amount calculation method and system, which dynamically corrects the flow calculation under non-uniform pressure field by real-time monitoring of the pressure difference of the left and right sides of the secondary air; solves the measurement failure problem caused by non-uniform pressure in the circumferential direction of the air preheater, realizes accurate calculation of air leakage amount under complex working conditions, and improves the working condition adaptability;

[0062] 3) The present application provides a four-warehouse rotary air preheater air leakage amount calculation method and system, which is based on regression method and pressure field analysis, and function fitting of flow ratio and pressure ratio under different working conditions, improves the measurement reliability under all working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is a method flowchart of an embodiment of the present application;

[0064] Figure 2 is a schematic diagram of an air preheater of an embodiment of the present application. DETAILED DESCRIPTION

[0065] The specific embodiments of the present application are described below to facilitate understanding of the present application by those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all inventions utilizing the concept of the present application are within the scope of protection.

[0066] The application provides the following technical solutions: a method and system for calculating air leakage of a four-division-bin rotary air preheater.

[0067] Embodiment 1

[0068] Specifically referring to Figure 1 The embodiment provides a method for calculating air leakage of a four-division-bin rotary air preheater, and the specific steps include:

[0069] S1, obtaining relevant data of primary air, secondary air and flue gas bin of the four-division-bin rotary air preheater through calibration and online measurement;

[0070] According to actual operation, the relevant data of the four-division-bin rotary air preheater can come from a plant-level monitoring system SIS or a distributed control system DCS, or from newly added measuring points; according to needs, primary air and secondary air flow pressure and flue gas bin oxygen content measuring points are added, and sometimes there are measuring points that can be used in the field;

[0071] The primary air, secondary air and flue gas bin have calibration holes at the inlet and outlet. Flow, velocity field, pressure field, oxygen content field and other calibration tests are carried out under specified operating conditions;

[0072] The installation position of the primary air inlet and outlet flow measuring meter is specifically a conventional device selected at a position meeting the straight pipe segment requirement, or a preset special device selected at a position of a bend pipe or a short straight pipe segment;

[0073] The installation position of the secondary air inlet and outlet flow measuring meter is specifically installed on the main pipe and the single-side branch pipe, or installed on the branch pipes on both sides; if installed on the branch pipe, the installation mode in the patent with the publication number CN103837703A can be referred to; in order to ensure that the flows on both sides are consistent, the resistance coefficient of the bifurcated pipe can be adjusted, and a flow guide fin can be additionally installed; or in order to ensure that the temperatures on both sides are consistent, the flow guide fin can be used to increase the flow on the high-temperature side of the flue gas and reduce the flow on the low-temperature side of the flue gas;

[0074] The installation position of the flue gas bin flow measuring meter is specifically at the outlet of the four-division-bin rotary air preheater, and the inlet and outlet and the left and right sides of the flue gas bin are calculated in zones; the calculation method of the flow, velocity and air leakage parameters is to use dynamic average value and CEMS data;

[0075] S2, please refer to Figure 2 According to the relevant data, the air leakage of the four-division-bin rotary air preheater is calculated online, and the air leakage includes primary air leakage, primary air leakage into secondary air on the left and right sides and flue gas bin air leakage;

[0076] Wherein, the blue arrow represents the primary air inlet and outlet flow, the yellow arrow represents the secondary air inlet and outlet flow on the right side of the air preheater, the green arrow represents the secondary air inlet and outlet flow on the left side of the air preheater, the red arrow represents the flue gas inlet and outlet flow on the right side of the air preheater, and the purple arrow represents the flue gas inlet and outlet flow on the left side of the air preheater;

[0077] The blue gradient green arrow represents the leakage of the primary air flow into the secondary air on the left side of the air preheater, i.e. the left side primary air leakage;

[0078] The blue gradient yellow arrow represents the leakage of the primary air flow into the secondary air on the right side of the air preheater, i.e. the right side primary air leakage;

[0079] The green gradient red arrow represents the leakage of the secondary air on the left side of the air preheater into the left side flue gas chamber, i.e. the leakage of the left side secondary air into the flue gas chamber;

[0080] The yellow gradient purple arrow represents the leakage of the secondary air on the right side of the air preheater into the right side flue gas chamber, i.e. the leakage of the right side secondary air into the flue gas chamber;

[0081] S3, based on the primary air inlet flow and the primary air outlet flow, the primary air leakage is obtained, which is expressed by the formula:

[0082] f p =f pin -f pout ;

[0083] In the formula, f p represents the primary air leakage; f pin represents the primary air inlet flow; and f pout represents the primary air outlet flow;

[0084] S4, based on the pressure difference of the primary air on the left and right sides of the secondary air of the air preheater, the leakage of the primary air into the left and right secondary air is calculated;

[0085] S41, the calculation step of the pressure difference of the primary air on the left and right sides of the secondary air of the air preheater is specifically:

[0086] Based on the inlet and outlet pressures of the primary air and the left and right secondary air of the air preheater, the average pressure difference of the primary air on the left and right secondary air is calculated;

[0087] Based on the average pressure difference of the primary air on the left and right secondary air, the leakage of the primary air to the secondary air is calculated, which is expressed by the formula:

[0088]

[0089] In the formula, k spl represents the flow pressure coefficient of the primary air on the left side secondary air; and k psrrepresents the flow pressure coefficient of the primary air to the right secondary air; f psl represents the flow of the primary air leaking into the left secondary air; f psr represents the flow of the primary air leaking into the right secondary air; Δp psl represents the average pressure difference of the primary air to the left secondary air; Δp psr represents the average pressure difference of the primary air to the right secondary air; p pin represents the primary air inlet pressure; p pout represents the primary air outlet pressure; p sinl represents the left secondary air inlet pressure; p soutl represents the left secondary air outlet pressure; p sinr represents the right secondary air inlet pressure; P soutr represents the right secondary air outlet pressure;

[0090] S5, calculating the secondary air inlet flow and the secondary air outlet flow based on the secondary air bifurcated pipe;

[0091] S51, the secondary air inlet flow includes the flow through the air preheater manifold to the left bifurcated pipe and the right bifurcated pipe, specifically:

[0092] The pressure relationship between the air preheater manifold and the left bifurcated pipe is expressed in the formula as:

[0093] p sinl = p sfout -k sin ·(f sin ) 2 -k sinl ·(f sinl ) 2

[0094] In the formula, p sfout represents the pressure at the outlet of the air blower; k sin represents the flow pressure coefficient of the secondary air at the inlet of the air preheater manifold; f sin represents the secondary air flow at the inlet of the air preheater manifold, i.e. the secondary air inlet flow; k sinl represents the flow pressure coefficient of the secondary air at the inlet of the left bifurcated pipe; p sinl represents the secondary air pressure at the inlet of the left bifurcated pipe; f sinl represents the secondary air flow at the inlet of the left bifurcated pipe, i.e. the left secondary air flow;

[0095] The pressure relationship between the air preheater manifold and the right bifurcated pipe is expressed in the formula as:

[0096] p sinl = p sfout -k sin ·(f sin ) 2-k sinr ·(f sinr ) 2 ;

[0097] In the formula, k sinr p represents the flow pressure coefficient of the secondary air at the inlet of the right-side bifurcation pipe. sinr This indicates the secondary air pressure at the inlet of the right-side branch pipe; f sinr This indicates the secondary air flow rate at the inlet of the right-side branch pipe, i.e., the secondary air flow rate on the right side.

[0098] After the pressure coefficient is determined through calibration testing, the air leakage can be calculated online.

[0099] Determine k sin k sinl k sinr At the same time, multiple operating conditions should be tested, including differences in flow rate and differences in back pressure at the branch outlet.

[0100] S52. The specific steps for obtaining the secondary air flow rates at the inlets of the left and right branch pipes of the air preheater are as follows:

[0101] If the pressure is uneven along the circumference of the air preheater, the pressure at the secondary air inlets on both sides of the air preheater will change periodically. The expressions for the flow rate and pressure at the secondary air inlets on both sides are given by the following formula:

[0102]

[0103] For any working condition:

[0104] p sinl -p sinr =k sinl *f sinl 2 -k sinr *f sinr 2 ;

[0105] In the formula, p sinlmax This indicates the highest back pressure at the outlet of the left branch pipe of the air preheater; p sinlmin Indicates the lowest back pressure on the left side of the air preheater; p sinrmax This indicates the highest back pressure at the outlet of the right-side branch pipe of the air preheater; p sinrmin This indicates the lowest back pressure at the outlet of the right-side branch pipe of the air preheater; p sinl This indicates the inlet pressure of the flue gas chamber on the left side of the secondary air supply; k sin k represents the secondary air inlet flow pressure coefficient. sinl Indicates the inlet flow pressure coefficient of the flue gas chamber on the left side of the secondary air supply; k sinr This indicates the flow pressure coefficient of the secondary air inlet on the right side;

[0106] If the difference between the flow pressure coefficients of the left and right secondary air is within a preset interval, it indicates that the left flow pressure coefficient is equal to the right flow pressure coefficient k sinl = k sinr ;

[0107] Substitute the flow pressure coefficients of the left and right secondary air into the expression, and obtain the right secondary air inlet flow equal to the left secondary air inlet flow ;

[0108] S53, the acquisition steps of the secondary air flow of the left and right bifurcated pipes at the outlet of the air preheater are as follows:

[0109] When the air preheater pressure is uniform in the circumferential direction and the structure of the left and right outlet pipes of the air preheater secondary air is symmetrical, the pressures at the left and right outlets of the air preheater are the same, and the left secondary air outlet flow is equal to the right secondary air outlet flow, which is expressed as f soutl = f soutr , wherein f soutl represents the left flow of the secondary air outlet bifurcated pipe; and f soutr represents the right flow of the secondary air outlet bifurcated pipe.

[0110] Generally, the flow field at the intersection of the air duct is turbulent, and the pressure measurement is not easy to be accurate. When there is a pressure gauge downstream of the left and right air ducts at the outlet of the air preheater secondary air, the following calculation can be performed through calibration:

[0111] (p soutl -p sout )+(p sout -p soutp ) = k soutl *f soutl 2 +k soutp *(f soutl +f soutr ) 2 ;

[0112] (p soutr -p sout )+(p sout -p soutp ) = k soutr *f soutr 2 +k soutp *(f soutl +f soutr ) 2 ;

[0113] In the formula, p sout represents the pressure at the left and right sides of the outlet of the air preheater secondary air; and p soutprepresents the pressure of the left side of the outlet of the secondary air of the air preheater; k soutp represents the flow pressure coefficient of the left side of the outlet of the secondary air of the air preheater to the merging point; k soutl represents the flow pressure coefficient of the left side of the outlet of the secondary air of the air preheater to the merging point; k soutr represents the flow pressure coefficient of the right side of the outlet of the secondary air of the air preheater to the merging point, the above formula represents the meaning of p sout , but cannot be directly calculated;

[0114] After testing multiple working conditions, p sout , k soutp , k soutl , k soutr , etc. can be calculated;

[0115] If the pressure is uneven in the circumferential direction of the air preheater, the pressure at the left and right outlets of the air preheater will periodically change, and the expressions of the left and right secondary air outlet flow rates are obtained, which are expressed by formulas as follows:

[0116] p soutlmax -p soutr |p soutlmax =k soutl *f soutl |p soutlmax 2 -k soutr *f soutr |p soutlmax 2 ;

[0117] p soutlmin -p soutr |p soutlmin =k soutl *f soutl |p soutlmin 2 -k soutr *f soutr |p soutlmin 2 ;

[0118] p soutrmax -p soutl |p soutlmax =k soutr *f soutr |p soutrmax 2 -k soutl *f soutl |p soutrmax 2 ;

[0119] p soutrmin -p soutl |p soutrmin =ksoutr *f soutr |p soutrmin 2 -k soutl *f soutl |p soutrmin 2 ;

[0120] For any operating condition, we have:

[0121] p soutl -p soutr =k soutl *f soutl 2 -k soutr *f soutr 2 ;

[0122] wherein p soutlmax represents the maximum secondary air pressure on the left side within a rotation period at the outlet of the air preheater; p soutlmin represents the minimum secondary air pressure on the left side within a rotation period at the outlet of the air preheater; p soutrmax represents the maximum secondary air pressure on the right side within a rotation period at the outlet of the air preheater; p soutrmin represents the minimum secondary air pressure on the right side within a rotation period at the outlet of the air preheater; p soutl represents the pressure on the left side at the outlet of the secondary air preheater; p soutr represents the pressure on the right side at the outlet of the secondary air preheater; k soutl represents the flow pressure coefficient on the left side at the outlet of the secondary air; k soutr represents the flow pressure coefficient on the right side at the outlet of the secondary air;

[0123] The pressure drops of the secondary air at the left and right outlets are calculated respectively, and substituted into the expression to obtain the secondary air outlet flow rates on the left and right sides, which are expressed by the formula:

[0124]

[0125] wherein Δp soutl represents the pressure drop of the secondary air from the outlet of the left bifurcated pipe to the intersection; Δp soutr represents the pressure drop of the secondary air from the outlet of the right bifurcated pipe to the intersection;

[0126] S6, using the primary air, secondary air and flue gas inlet and outlet flow rates, the air preheater left and right secondary air leakage into the flue gas leakage amount, that is, the flue gas leakage amount is calculated;

[0127] In an embodiment, the flue gas leakage amount calculation step is specifically:

[0128] Using the flow meter of the flue gas online monitoring system, the flue gas data is obtained;

[0129] Based on the flue gas data, the oxygen content, flow rate and pressure at the inlet and outlet of the left and right flue gas chambers are calculated

[0130] For equal-area point calibration, the oxygen content at the inlet of the left flue gas chamber is calculated, which is expressed in a formula as follows:

[0131] O inlt =∑(O inlt,i ×v inlt,i ) / ∑v inlt,i , i=1, 2,..., nO inl ;

[0132] kO inl =O inlt,i / O inlot ;

[0133] O inla =kO inl *O inlo ;

[0134]

[0135]

[0136] p ginla =kp ginl *p ginlo ;

[0137] In the formula, O inlt represents the average oxygen content at the inlet of the left flue gas chamber during calibration test; O inlt,i represents the oxygen content at the inlet of the left flue gas chamber at the i-th calibration point; v inlt,i represents the velocity at the inlet of the left flue gas chamber at the i-th calibration point; nO inl represents the number of calibration points of the oxygen content at the inlet of the left flue gas chamber; i represents the index value of the i-th calibration point; kO inl represents the correction coefficient of the oxygen content at the inlet of the left flue gas chamber; O inlot represents the running oxygen content at the inlet of the left flue gas chamber during calibration; O inla represents the corrected oxygen content at the inlet of the left flue gas chamber; O inlo represents the running oxygen content at the inlet of the left flue gas chamber before correction; v glt represents the average flow rate during calibration of the left flue gas chamber; nv gl represents the number of calibration points of the velocity of the left flue gas chamber; v glt,j represents the flow rate of the left flue gas chamber at the j-th velocity calibration point; j represents the index value of the j-th velocity calibration point; p ginlt represents the average calibration inlet pressure of the left flue gas chamber; np ginl represents the number of calibration points of the pressure at the inlet of the left flue gas chamber; p ginl,kP represents the left flue gas chamber inlet pressure of the kth speed calibration point; k represents the index value of the kth left flue gas chamber inlet pressure calibration point; kp ginl P represents the left flue gas chamber inlet pressure correction coefficient; ginlot P represents the left flue gas chamber running outlet pressure at calibration; ginla P represents the corrected left flue gas chamber inlet pressure; ginlo P represents the left flue gas chamber inlet pressure before correction at running;

[0138] The left flue gas chamber outlet oxygen content is calculated, which is expressed by the formula:

[0139] O outlt =∑(O outlt,i ×v outlt,i ) / ∑v outlt,i , i=1, 2, …, nO outl ;

[0140] kO outl =O outlt,i / O outlot ;

[0141] O outla =kO outl *O outlo ;

[0142]

[0143]

[0144] p goutla =kp goutl *p goutlo ;

[0145] In the formula, O outlt represents the average oxygen content of the left flue gas chamber outlet calibration; O outlt,i represents the left flue gas chamber outlet oxygen content of the ith calibration point; v outlt,i represents the left flue gas chamber outlet speed of the ith calibration point; nO outl represents the number of left flue gas chamber outlet oxygen calibration points; kO outl represents the left flue gas chamber outlet oxygen correction coefficient; O outlot represents the left flue gas chamber outlet oxygen content at running at calibration; O outla represents the corrected left flue gas chamber outlet oxygen content; O outlo represents the left flue gas chamber outlet oxygen content before correction; p goutlt represents the left flue gas chamber average calibration outlet pressure; np goutlt represents the number of left flue gas chamber outlet pressure calibration points; p goutl,zPz represents the left flue gas chamber outlet pressure of the zth velocity calibration point; z represents the index value of the zth left flue gas chamber outlet pressure calibration point; kp goutl P represents the left flue gas chamber outlet pressure correction coefficient; goutlot P represents the left flue gas chamber outlet pressure at calibration; goutla P represents the corrected left flue gas chamber outlet pressure; goutlo P represents the left flue gas chamber outlet pressure before correction at operation;

[0146] The right inlet flue gas chamber oxygen content is calculated, and the formula is as follows:

[0147] O inrt =∑(O inrt,i ×v inrt,i ) / ∑v inrt,i , i=1, 2, …, nO inr ;

[0148] kO inr =O inrt,i / O inrot ;

[0149] O inra =kO inr *O inro ;

[0150]

[0151] p ginra =kp ginr *p ginro ;

[0152] In the formula, O inrt represents the right inlet flue gas chamber average oxygen content; O inrt,i represents the right inlet flue gas chamber oxygen content of the ith calibration point; v inrt,i represents the right inlet flue gas chamber velocity of the ith calibration point; nO inr represents the number of right inlet flue gas chamber oxygen calibration points; kO inr represents the right inlet flue gas chamber oxygen correction coefficient; O inrot represents the right inlet flue gas chamber oxygen content at operation at calibration; O inra represents the corrected right inlet flue gas chamber oxygen content; O inro represents the right inlet flue gas chamber oxygen content before correction at operation; v grt represents the right calibration average flow rate; nv gr represents the number of right velocity calibration points; v grt,j represents the right flow rate of the jth velocity calibration point; p ginrt represents the right average calibration inlet pressure; np ginrtrepresents the number of right side inlet flue gas chamber pressure calibration points; p ginr,k represents the right side inlet flue gas chamber pressure of the kth speed calibration point; kp ginr represents the right side inlet flue gas chamber pressure correction coefficient; p ginrot represents the right side inlet flue gas chamber pressure at calibration; p ginra represents the corrected right side inlet flue gas chamber pressure; p ginro represents the right side inlet flue gas chamber pressure at operation before correction;

[0153] The right side outlet flue gas chamber oxygen amount is calculated, expressed by the formula:

[0154] O outrt =∑(O outrt,i ×v outrt,i ) / vv outrt,i , i=1, 2,..., nO outr ;

[0155] kO outr =O outrt,i / O outrot ;

[0156] O outra =kO outr *O outro ;

[0157]

[0158] p goutra =kp goutr *p goutro ;

[0159] In the formula, O outrt represents the right side outlet flue gas chamber average oxygen amount; O outrt,i represents the right side outlet flue gas chamber oxygen amount of the ith calibration point; v outrt,i represents the right side outlet flue gas chamber speed of the ith calibration point; nO outr represents the number of right side outlet flue gas chamber oxygen calibration points; kO outr represents the right side outlet flue gas chamber oxygen correction coefficient; O outrot represents the right side outlet flue gas chamber oxygen amount at operation at calibration; O outra represents the corrected right side outlet flue gas chamber oxygen amount; O outro represents the right side outlet flue gas chamber oxygen amount at operation before correction; p goutrt represents the right side average calibration outlet pressure; np goutrt represents the number of right side outlet flue gas chamber pressure calibration points; p goutr,z represents the right side outlet flue gas chamber pressure of the zth speed calibration point; kp goutrp represents the pressure correction factor for the right-side outlet flue gas chamber; goutrot p represents the pressure of the right-side outlet flue gas chamber during calibration. goutra This indicates the corrected right-side outlet flue gas chamber pressure; p goutro This indicates the pressure of the right-side outlet flue gas chamber during operation before the correction.

[0160] The flue gas outlet flow rate is calculated using the following formula:

[0161] f gout =f m (21-O m ) / (21-O out );

[0162] In the formula, f gout Indicates the flue gas outlet flow rate; O m This indicates the oxygen content displayed at the flow measurement point of the continuous emission measurement system; f m This indicates the flow rate displayed at the flow measurement point of the continuous emission measurement system; O out Indicates the oxygen content at the air preheater outlet;

[0163] The inlet flow rate of the flue gas chamber can be calculated using the following formula:

[0164] f gin =f gout (21-O out ) / (21-O in )=f m (21-O m ) / (21-O in );

[0165] In the formula, f gin Indicates the flue gas inlet flow rate; O in Indicates the oxygen content at the air preheater inlet;

[0166] Based on the inlet and outlet oxygen levels of the flue gas chambers on both the left and right sides, the air leakage rate of the secondary air entering the flue gas chambers on both sides is calculated, i.e., the air leakage rate of the flue gas chambers, which is expressed by the formula:

[0167] f sgl =f goutl (21-O outla )(1 / (21-O outla )-1 / (21-O inla ));

[0168] f sgr =f goutr (21-O outra )(1 / (21-O outra )-1 / (21-O inra ));

[0169] f g = f sgl + f sgr ;

[0170] wherein f goutl represents the left side outlet flue gas chamber flow rate; f goutr represents the right side outlet flue gas chamber flow rate; f sgl represents the left side secondary air leakage into the flue gas chamber; f sgr represents the right side secondary air leakage into the flue gas chamber; and f g represents the flue gas chamber air leakage.

[0171] In another embodiment, the flue gas chamber air leakage calculation step is specifically as follows:

[0172] A plurality of calibration points are arranged in the left and right flue gas chambers, and at least one measuring point is taken at each calibration point.

[0173] The pressure difference at the inlet and outlet of the left and right flue gas chambers in the current period or working condition is collected through the measuring points.

[0174] The calibration points of the flue gas chamber inlet and outlet are radially advanced and retreated along the depth direction, the angle of each measuring hole in the depth direction is the same, and the measuring holes are evenly distributed in angle. A plurality of speed measuring devices can be inserted in one measuring hole at the same time, and are arranged at different depths in the radial direction. The inlet and outlet are performed at the same time, and a plurality of points are measured at the same time. Therefore, a multi-point data acquisition system can be used for data acquisition. However, the test data is different even at the same heat transfer unit position at different location calibration points.

[0175] For each calibration point, if there are y calibration holes on the left and right sides, and M measuring points are taken in the radial depth direction of each calibration hole, then for the left side, the inlet and outlet measuring point pressures at time ti are p l,in,ti,i,a and p l,out,ti,i,a , wherein p l,in,ti,i,a represents the inlet pressure of the left side i-th calibration point at the a-th measuring point, p l,out,ti,i,a represents the outlet pressure of the left side i-th calibration point at the a-th measuring point; and the pressure difference of the left side i-th calibration point at time ti is Δp l,ti = p l,in,ti,i,a -p l,out,ti,i,a ; for the right side, the inlet and outlet measuring point pressures at time ti are p r,in,ti,i,a and p r,out,ti,i,a , and the inlet and outlet pressure difference is Δp r,ti = p r,in,ti,i,a -p r,out,ti,i,a , wherein p r,in,ti,i,a represents the inlet pressure of the right side i-th calibration point at the a-th measuring point, and p r,out,ti,i,a represents the outlet pressure of the right side i-th calibration point at the a-th measuring point.

[0176] Generally, the pressure or pressure difference of each point, whether on the left side or the right side, is periodically changed under stable working conditions, so at the same time ti, the left side has and the right side has If the time from the previous calibration hole to the next calibration point is ts, at ti+ts, the left side has and the right side has

[0177] If the heat transfer unit rotates one circle, and the time for one rotation is tr, at ti+tr, the left side has and the right side has The average differential pressure on the left side is and the average differential pressure on the right side is where Δp l,ti represents the pressure difference on the left side at time ti, and Δp r,ti represents the pressure difference on the right side at time ti.

[0178] In addition, the correlation coefficient can be used to determine the blocking condition of the heat transfer unit. Since online data cannot be used, actual measurement needs to be performed using calibration measurement holes. Periodic or as-needed testing can be performed, and such testing can be performed on primary air, secondary air, or flue gas. It is more convenient to perform the testing on the flue gas, which is taken as an example here.

[0179] For any position on the heat transfer unit, it will experience during rotation, so as long as measurement is performed on a group of measurement holes, if the average values of the differential pressures tested at the same position of the heat transfer unit before and after on the left side are and the correlation coefficient is

[0180]

[0181] When the correlation coefficient of historical measurement data and real-time measurement data is small, for example, less than 0.8, it indicates that the air preheater is blocked, and calibration testing needs to be performed again.

[0182] Similarly, circumferential correlation calculation can also be performed. In addition to correlation calculation of the same position at different times, correlation calculation of different positions at the same time and different positions at different times can also be performed as needed.

[0183] Load, flow, and other working condition changes have a certain influence on the correlation coefficient, and working condition data similar to the working condition should be selected for correlation calculation.

[0184] Let the running inlet and outlet running measurement point pressures on the left side at time ti be p ol,in,ti and p ol,out,ti , and the left side running differential pressure be Δp ol,ti = p ol,in,ti-p ol,out,ti , the left side ti time operation measuring point pressure is p or,in,ti and p or,out,ti , the right side operation differential pressure is Δp or,ti =p or,in,ti -p or,out,ti ;

[0185] The function relationship between the pressure difference of the left and right flue gas bins and the preset working condition coefficient is fitted by using regression method, and the inlet and outlet flow rates of the left and right flue gas bins are obtained, which is expressed by the following formula:

[0186]

[0187] In the formula, a c represents the coefficient of the cth order; n represents the order; Δp l represents the pressure difference of the left flue gas bin, and Δp r represents the pressure difference of the right flue gas bin.

[0188] The data needs multiple working conditions and is obtained by calibration;

[0189] The air leakage amount of the left and right flue gas bins is obtained based on the inlet and outlet flow rates of the flue gas bin;

[0190] In another embodiment, the calculation step of the air leakage amount of the flue gas bin is specifically:

[0191] The air leakage amount of the flue gas bin is generated by the leakage of the secondary air into the flue gas bin, that is, the secondary air leakage amount is equal to the air leakage amount of the flue gas bin;

[0192] The air leakage amount of the flue gas bin is obtained based on the secondary air leakage amount, which is expressed by the following formula:

[0193] f s =f sin -f sout =f sinl -f soutl +f sinr -f soutr =f goutl -f ginl +f goutr -f ginr +(f poutl -f pinl +f poutr -f pinr );or

[0194] f s =f sin -f sout =f sinl -f soutl +f sinr -f soutr =f g -fp ;

[0195] wherein f s represents the secondary air leakage amount; f sin represents the secondary air inlet flow rate; f sout represents the secondary air outlet flow rate; f sinl represents the secondary air flow rate at the left bifurcated pipe inlet; f sinr represents the secondary air flow rate at the right bifurcated pipe inlet; f soutl represents the secondary air flow rate at the left bifurcated pipe outlet; f soutr represents the secondary air flow rate at the right bifurcated pipe outlet; f g represents the flue gas chamber leakage amount; f p represents the primary air leakage amount.

[0196] Embodiment 2:

[0197] The present application also provides a leakage amount calculation system of the four-division chamber rotary air preheater, which comprises a data acquisition module and a leakage amount calculation module:

[0198] The data acquisition module is used to obtain the relevant data of the primary air, the secondary air and the flue gas chamber of the four-division chamber rotary air preheater through calibration and online measurement; and the relevant data is transmitted to the leakage amount calculation module.

[0199] The leakage amount calculation module is used to calculate the leakage amount of the four-division chamber rotary air preheater online according to the relevant data, wherein the leakage amount comprises the primary air leakage amount, the leakage amount of the primary air into the left and right secondary air, and the flue gas chamber leakage amount.

[0200] The primary air leakage amount is obtained based on the primary air inlet flow rate and the primary air outlet flow rate.

[0201] The leakage amount of the primary air into the left and right secondary air is calculated based on the pressure difference of the primary air to the left and right secondary air of the air preheater.

[0202] The secondary air inlet flow rate and the secondary air outlet flow rate are calculated based on the secondary air bifurcated pipe.

[0203] The leakage amount of the left and right secondary air into the flue gas chamber, i.e. the flue gas chamber leakage amount, is calculated by using the primary air, the secondary air and the flue gas chamber inlet and outlet flow rates.

[0204] It is worth mentioning that the system, the electronic device and the computer readable storage medium of the present application are based on the same principle as the method of embodiment 1, and will not be described here.

[0205] The above merely illustrates the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which are made by using the content of the present application specification and drawings, are also included in the patent protection scope of the present application.

Claims

1. A method for calculating the air leakage of a four-compartment rotary air preheater, characterized in that, The method includes: The relevant data of the primary air, secondary air and flue gas chamber of the four-compartment rotary air preheater are obtained through calibration and online measurement; the air leakage of the four-compartment rotary air preheater is calculated online based on the relevant data, and the air leakage includes the primary air leakage, the primary air leakage into the secondary air on the left and right sides and the flue gas chamber leakage. The primary air leakage rate is obtained based on the primary air inlet flow rate and the primary air outlet flow rate. Based on the pressure difference between the primary air and the secondary air on the left and right sides of the air preheater, calculate the leakage of primary air into the secondary air on the left and right sides. Calculate the secondary air inlet flow and secondary air outlet flow based on the secondary air bifurcation pipe; Calculate the air leakage of the air preheater into the flue gas chamber by using the primary air, secondary air, and flue gas chamber inlet and outlet flow rates.

2. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for calculating the pressure difference between the primary air and the secondary air on both sides of the air preheater are as follows: Based on the inlet and outlet pressures of the primary and secondary air on the left and right sides of the air preheater, calculate the average pressure difference between the primary air and the secondary air on the left and right sides. The leakage of primary air to secondary air on the left and right sides is calculated based on the average pressure difference between the primary air and the secondary air on the left and right sides.

3. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The secondary air inlet flow rate includes the flow rate through the air preheater main pipe to the left and right branch pipes, specifically: The pressure relationship between the air preheater main pipe and the left branch pipe is expressed by the formula: ； In the formula, This indicates the pressure at the outlet of the blower; This indicates the flow pressure coefficient of the secondary air at the inlet of the air preheater main pipe; This indicates the secondary air flow rate at the inlet of the air preheater main pipe, i.e., the secondary air inlet flow rate; This indicates the flow pressure coefficient of the secondary air at the inlet of the left-side branch pipe; This indicates the secondary air pressure at the inlet of the left-side branch pipe; This indicates the secondary airflow at the inlet of the left branch pipe, i.e., the secondary airflow on the left side; The pressure relationship between the air preheater main pipe and the right-side branch pipe is expressed by the formula: ； In the formula, This indicates the flow pressure coefficient of the secondary air at the inlet of the right-side bifurcation pipe; This indicates the secondary air pressure at the inlet of the right-side branch pipe; This indicates the secondary airflow at the inlet of the right-side branch pipe, i.e., the right-side secondary airflow.

4. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for obtaining the secondary air flow rates at the inlets of the left and right branch pipes of the air preheater are as follows: If the pressure is uneven in the circumferential direction of the air preheater, the pressure of the secondary air inlet on the left and right sides of the air preheater will change periodically, and the expressions for the flow rate and pressure of the secondary air inlet on the left and right sides can be obtained. Determine the relationship between the flow pressure coefficients of the secondary winds on the left and right sides. If the difference between the flow pressure coefficients of the secondary winds on the left and right sides is within a preset range, it means that the flow pressure coefficient on the left side is equal to the flow pressure coefficient on the right side. Substituting the flow pressure coefficients of the secondary air on both sides into the expression, we obtain that the inlet flow rate of the secondary air on the right side is equal to the inlet flow rate of the secondary air on the left side.

5. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for obtaining the secondary air flow rates of the left and right branch pipes at the air preheater outlet are as follows: When the air preheater pressure is uniform along the circumference, the pressure at the outlets on both the left and right sides of the air preheater is the same, resulting in the secondary air outlet flow rate on the left side being equal to that on the right side.

6. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for obtaining the secondary air flow rates of the left and right branch pipes at the air preheater outlet are as follows: If the pressure is uneven in the circumferential direction of the air preheater, the pressure at the outlets on the left and right sides of the air preheater will change periodically, and the expressions for the secondary air outlet flow rates on the left and right sides can be obtained. Calculate the pressure drop of the secondary air at the left and right outlets respectively, and substitute it into the expression to obtain the flow rate of the secondary air outlets on the left and right sides.

7. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for calculating the air leakage of the flue gas chamber are as follows: Flue gas data is obtained using the flow meter of the online flue gas monitoring system; Based on the flue gas data, the oxygen content, flow rate, and pressure at the inlet and outlet of the flue gas chambers on both the left and right sides are calculated. Based on the inlet and outlet oxygen levels of the flue gas chambers on both the left and right sides, the air leakage rate of the secondary air entering the flue gas chambers on both sides is calculated, i.e., the air leakage rate of the flue gas chambers, which is expressed by the formula: ； In the formula, Indicates the air leakage rate of the flue gas chamber; This indicates the amount of secondary air leaking into the flue gas chamber from the left side; This indicates the amount of secondary air leaking into the flue gas chamber from the right side.

8. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for calculating the air leakage of the flue gas chamber are as follows: Multiple calibration points are set up in the left and right flue gas chambers, and at least one measurement point is taken at each calibration point; The pressure difference between the inlet and outlet of the left and right flue gas chambers is collected by measuring points during the current cycle or operating condition. The inlet and outlet flow rates of the left and right flue gas chambers are obtained by fitting the functional relationship between the pressure difference between the left and right flue gas chambers and the preset operating condition coefficient using the regression method. The inlet and outlet flow rates of the flue gas chambers are calculated based on the inlet and outlet flow rates of the left and right flue gas chambers. The air leakage of the flue gas chamber is obtained based on the inlet and outlet flow rates of the flue gas chamber, and can be expressed by the following formula: ； In the formula, Indicates the air leakage rate of the flue gas chamber; Indicates the flue gas outlet flow rate; This indicates the inlet flow rate of the flue gas chamber.

9. The method for calculating the air leakage of a four-compartment rotary air preheater according to claim 1, characterized in that, The specific steps for calculating the air leakage of the flue gas chamber are as follows: The air leakage in the flue gas chamber is caused by secondary air leaking into the flue gas chamber; that is, the air leakage of secondary air is equal to the air leakage in the flue gas chamber. The air leakage of the flue gas chamber is obtained based on the secondary air leakage, and is expressed by the formula: ； or ； In the formula, Indicates the amount of secondary air leakage; Indicates the secondary air inlet flow rate; Indicates the secondary air outlet flow rate; This indicates the secondary airflow rate at the inlet of the left-side branch pipe; This indicates the secondary air flow rate at the inlet of the right-side branch pipe; This shows the secondary air flow rate at the outlet of the left-side branch pipe; This indicates the secondary air flow rate at the outlet of the right-side branch pipe; Indicates the air leakage rate of the flue gas chamber; This indicates the amount of air leakage in a single pass.

10. A system for calculating the air leakage of a four-compartment rotary air preheater, characterized in that, The system includes a data acquisition module and an air leakage calculation module: The data acquisition module is used to obtain relevant data on the primary air, secondary air, and flue gas chamber of the four-compartment rotary air preheater through calibration and online measurement; and to transmit the relevant data to the air leakage calculation module. The air leakage calculation module is used to calculate the air leakage of the four-compartment rotary air preheater online based on relevant data. The air leakage includes primary air leakage, primary air leakage into the secondary air on the left and right sides, and flue gas compartment leakage. The primary air leakage rate is obtained based on the primary air inlet flow rate and the primary air outlet flow rate. Based on the pressure difference between the primary air and the secondary air on the left and right sides of the air preheater, calculate the leakage of primary air into the secondary air on the left and right sides. Based on the pressure difference between the secondary air and the flue gas chambers on the left and right sides of the air preheater, the leakage of secondary air into the flue gas chambers on the left and right sides is calculated. Based on the pressure difference between the primary air and the secondary air on the left and right sides of the air preheater, calculate the leakage of primary air into the secondary air on the left and right sides. Calculate the secondary air inlet flow and secondary air outlet flow based on the secondary air bifurcation pipe; Calculate the air leakage of the air preheater into the flue gas chamber by using the primary air, secondary air, and flue gas chamber inlet and outlet flow rates.

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