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

Abstract

The invention relates to a method and a system for calculating air leakage of a three-section rotary air pre-heater. The method comprises the following steps: acquiring related data of primary air, secondary air and a flue gas bin; the air leakage amount of primary air and secondary air is calculated on line; wherein the air leakage amount of the primary air comprises the air leakage amount of the primary air leaking into the flue gas bin and the air leakage amount of the primary air leaking into the secondary air; the air leakage amount of the secondary air comprises the air leakage amount of the secondary air leaking into the flue gas bin; the average differential pressure among the primary air, the secondary air and the flue gas bin is calculated through a variable flow method; the average differential pressure corresponding to the primary air or the secondary air is changed, and the air leakage coefficient of the primary air leaking into the smoke bin, the air leakage coefficient of the primary air leaking into the secondary air and the air leakage coefficient of the secondary air leaking into the smoke bin are obtained; the temperature correction coefficients of the primary air and the secondary air are calculated through the temperature correction coefficients; the air leakage coefficient and the temperature correction coefficient are combined, and the corrected air leakage amount of the primary air leaking into the flue gas bin, the corrected air leakage amount of the primary air leaking into the secondary air and the corrected air leakage amount of the secondary air leaking into the flue gas bin are calculated.

Description

Technical Field

[0001] The present application relates to the field of air leakage calculation of a three-compartment rotary air preheater, and mainly to a method and system for calculating the air leakage of a three-compartment rotary air preheater. Background Art

[0002] As a key energy recovery device in the boiler system, the rotary air preheater plays a vital role in the boiler's tail flue. Among various air preheaters, the three-compartment rotary air preheater is widely used in large boiler units due to its unique structure and operating characteristics. However, as the equipment continues to operate, the three-compartment rotary air preheater has exposed a series of problems that cannot be ignored, the most prominent of which is air leakage. Large amounts of air leakage have a multi-faceted negative impact on the safe and economical operation of the boiler unit. From the perspective of thermal efficiency, this part of the air leaking into the flue gas side greatly increases the flue gas flow discharged by the boiler.

[0003] Currently, common measurement methods either have limited accuracy, unable to accurately capture subtle changes in secondary air leakage; or are complex to operate, requiring significant manpower and time for regular testing, making it difficult to achieve true real-time online monitoring. This lack of monitoring technology prevents operators from obtaining timely and accurate real-time data on secondary air leakage, making it difficult to make scientific and rational operational decisions based on this data. Furthermore, due to the lack of accurate leakage data, maintenance personnel are unable to clearly identify specific maintenance priorities and directions during post-shutdown maintenance. This leads to blind inspections, increasing maintenance costs and making it difficult to fundamentally resolve the leakage problem.

[0004] For example, the Chinese invention patent with publication number “CN105021357A” discloses a method and device for determining the air preheater leakage rate, which specifically discloses “obtaining the average oxygen content at the air preheater inlet; determining the excess air coefficient at the air preheater outlet based on the average oxygen content at the air preheater inlet; determining the excess air coefficient at the air preheater outlet based on the excess air coefficient at the air preheater outlet; determining the air preheater no-leakage outlet flue gas temperature based on the air preheater inlet flue gas temperature, the air preheater outlet primary air temperature, the air preheater outlet secondary air temperature, the air preheater inlet primary air temperature and the air preheater inlet secondary air temperature; determining the air preheater flue gas leakage temperature based on the primary air temperature and the secondary air temperature; determining the air preheater no-leakage outlet flue gas temperature based on the air preheater no-leakage outlet flue gas temperature and the actual boiler exhaust gas temperature; determining the air preheater no-leakage outlet flue gas temperature based on the air preheater inlet flue gas temperature, the air preheater outlet primary air temperature, the air preheater outlet secondary air temperature, the air preheater inlet primary air temperature and the air preheater inlet secondary air temperature; determining the air preheater flue gas leakage temperature based on the air preheater no-leakage outlet flue gas temperature and the actual boiler exhaust gas temperature; determining the air preheater no-leakage outlet flue gas temperature based on the air preheater outlet flue gas temperature and the actual boiler exhaust gas temperature. and the air preheater flue gas leakage temperature, determine the increase in the air preheater outlet leakage coefficient; according to the increase in the air preheater outlet leakage coefficient and the air preheater inlet excess air coefficient, determine the air preheater leakage rate". However, the calculation process of this method depends on multiple parameters such as the air preheater inlet flue gas temperature and multiple wind temperatures, and the measurement accuracy of the parameters will directly affect the accuracy of the final leakage rate calculation, resulting in a large deviation in the entire calculation result. In addition, this method does not consider the influence of the differential pressure between the primary air, secondary air and flue gas bin on the leakage during the calculation process. For different leakage situations such as primary air leaking into secondary air, no targeted separate calculation and analysis is performed, and the leakage situation in different parts cannot be accurately understood, which is not conducive to accurately locating and solving the leakage problem. Summary of the Invention

[0005] In order to solve the above-mentioned problems existing in the prior art, the present application provides a method and system for calculating the air leakage of a three-compartment rotary air preheater.

[0006] The technical solution of this application is as follows:

[0007] On the one hand, the present invention provides a method for calculating the air leakage of a three-compartment rotary air preheater, the method comprising:

[0008] Obtain relevant data of primary air, secondary air and flue gas silo and perform preprocessing; calculate the air leakage of primary air and secondary air online based on the mass balance equation and the relevant data after preprocessing; wherein the air leakage of primary air includes the air leakage of primary air into flue gas silo and the air leakage of primary air into secondary air; the air leakage of secondary air includes the air leakage of secondary air into flue gas silo;

[0009] The average differential pressure between the primary air, secondary air and flue gas bin is calculated using the variable flow method; the average differential pressure corresponding to the primary air or secondary air is changed to obtain the leakage coefficient of the primary air leaking into the flue gas bin, the primary air leaking into the secondary air, and the secondary air leaking into the flue gas bin;

[0010] The temperature correction coefficient is used to calculate the temperature correction coefficient of the primary air and the secondary air; the air leakage coefficient and the temperature correction coefficient are combined to calculate the corrected air leakage of the primary air into the flue gas bin, the primary air into the secondary air, and the secondary air into the flue gas bin.

[0011] Preferably, the method further comprises calibrating relevant data according to calculation requirements.

[0012] Preferably, the air leakage of the primary air and the secondary air is calculated online based on the mass balance equation and the pre-processed relevant data, and is expressed as follows:

[0013] w p =w pin -w pout =w pg +w ps ;

[0014] w s =w sin -w sout =w sg -w ps ;

[0015] w g =w gin -w gout =w pg +w sg ;

[0016]

[0017] Where w p Indicates the primary air leakage volume; w s Indicates secondary air leakage; w g Indicates the air leakage of the flue gas bin;

[0018] w pin Indicates the primary air inlet flow rate; w sin Indicates the secondary air inlet flow rate; w gin Indicates the flow rate at the flue gas bin entrance; w pout Indicates the primary air outlet flow rate; w sout Indicates the secondary air outlet flow rate; w gout Indicates the outlet flow of the smoke bin; w pg Indicates the leakage of primary air into the flue gas bin; w ps Indicates the amount of air leakage from primary air into secondary air; w sg Indicates the amount of secondary air leaking into the flue gas bin.

[0019] Preferably, the differential pressure between the primary air and the smoke bin is calculated online and expressed as:

[0020]

[0021] Where Δp pg Indicates the average differential pressure between the primary air and the smoke bin; p pin Indicates the primary air inlet pressure; p gout Indicates the outlet pressure of the flue gas chamber; p pout Indicates the primary air outlet pressure; p gin Indicates the inlet pressure of the flue gas silo;

[0022] The average differential pressure between the secondary air and the flue gas bin is calculated online and expressed as:

[0023]

[0024] Where Δp sg Indicates the average differential pressure between the secondary air and the flue gas chamber; p sin Indicates the secondary air inlet pressure; p sout Indicates the secondary air outlet pressure;

[0025] The average differential pressure between the primary air and the secondary air is calculated online and expressed as:

[0026]

[0027] Where Δp ps Indicates the average differential pressure between primary and secondary air.

[0028] Preferably, the differential pressure of the primary air is changed to obtain the leakage coefficients of the primary air leaking into the smoke bin, the primary air leaking into the secondary air, and the secondary air leaking into the smoke bin, specifically:

[0029] The differential pressure of the primary air to the smoke bin is extrapolated to zero, and the leakage of the secondary air into the smoke bin is separated; the leakage coefficient of the primary air into the smoke bin is calculated under the leakage test of the preset working conditions, and is expressed as follows:

[0030] w g,n =w pg,n +w sg ;

[0031]

[0032] Where k pg Indicates the leakage coefficient of primary air into the smoke bin; n indicates the index value of the nth working condition; w pg,n Indicates the air leakage into the flue gas bin under the nth working condition; Δp pg,n It represents the average differential pressure between the primary air and the smoke bin under the nth working condition;

[0033] Calculate the air leakage coefficient of primary air into secondary air, expressed as follows:

[0034]

[0035] Where k ps Indicates the leakage coefficient of primary air into secondary air.

[0036] Preferably, the differential pressure of the secondary air is changed to obtain the leakage coefficient of the secondary air leaking into the flue gas bin, specifically:

[0037] The differential pressure of the secondary air to the smoke bin is extrapolated to zero, and the leakage of the primary air into the smoke bin is separated; the leakage coefficient of the secondary air into the smoke bin is calculated under the leakage test of the preset working conditions, and is expressed as follows:

[0038] w g,n =w pg +w sg,n ;

[0039]

[0040] Where k sg Indicates the leakage coefficient of secondary air into the flue gas bin; w sg,n Indicates the leakage of secondary air into the flue gas bin under the nth working condition; Δp sg,n It represents the average differential pressure between the secondary air and the flue gas bin under the nth operating condition.

[0041] Preferably, the temperature correction coefficients of the primary and secondary air are calculated using the temperature correction coefficients, specifically:

[0042] The temperature correction coefficient for calculating primary air leakage is expressed as follows:

[0043]

[0044] Where R p Indicates the temperature correction coefficient of primary air leakage; T p0in Indicates the primary air reference point inlet temperature; T p0out Indicates the primary air reference point outlet temperature; T pin Indicates the primary air inlet temperature; T pout Indicates the primary air outlet temperature;

[0045] The temperature correction coefficient for calculating secondary air leakage is expressed as follows:

[0046]

[0047] Where R s Indicates the temperature correction coefficient of secondary air leakage; T s0in Indicates the secondary air reference point inlet temperature; T s0out Indicates the secondary air reference point outlet temperature; T sinIndicates the secondary air inlet temperature; T sout Indicates the secondary air outlet temperature;

[0048] The corrected leakage of primary air into secondary air is expressed as follows:

[0049]

[0050] Where A ps Indicates the leakage area of ​​primary air into secondary air; ρ a Indicates the air density;

[0051] The corrected leakage of primary air into the flue gas bin is expressed as follows:

[0052] Δp pg =Δp ps +p s -p g ;

[0053]

[0054] Where A pg Indicates the leakage area ratio of primary air into the flue gas bin;

[0055] The corrected leakage of secondary air into the flue gas bin is expressed as follows:

[0056]

[0057] Where A sg Indicates the leakage area ratio of secondary air into the flue gas bin.

[0058] Preferably, the method further comprises conducting tests under low load and high load conditions; when under low load, reducing the primary air pressure or secondary air pressure at the air preheater; when under high load, increasing the primary air pressure or secondary air pressure at the air preheater;

[0059] While keeping the primary air pressure and smoke bin pressure constant, change the secondary air pressure at least once, measure the data of the corresponding working conditions, and obtain the relevant data of the primary air, secondary air and smoke bin;

[0060] While keeping the secondary air pressure and smoke bin pressure constant, change the primary air pressure at least once, measure the data of the corresponding working conditions, and obtain relevant data of the primary air, secondary air and smoke bin.

[0061] Preferably, the calculation of the corresponding air leakage area ratios of the primary air, secondary air and smoke bin is specifically as follows:

[0062] Under the initial working condition, the corresponding air leakage area ratio of primary air, secondary air and flue gas bin is 1;

[0063] After a preset number of operating conditions, determine whether the air leakage has increased. If increased, calculate the air leakage coefficient and air leakage area based on the increased air leakage.

[0064] On the other hand, the present invention also provides a system for calculating the air leakage of a three-compartment rotary air preheater, the system comprising a data acquisition module, an air leakage calculation module, a correction module, and a result output module, wherein:

[0065] The data acquisition module is used to acquire relevant data of primary air, secondary air and smoke bin, and perform preprocessing; and transmit the relevant data to the air leakage calculation module;

[0066] The air leakage calculation module is used to calculate the air leakage of primary air and secondary air online based on the mass balance equation and the relevant data after preprocessing; wherein the air leakage of primary air includes the air leakage of primary air into the smoke bin and the air leakage of primary air into the secondary air; the air leakage of secondary air includes the air leakage of secondary air into the smoke bin; the relevant data, the air leakage of primary air and secondary air are transmitted to the air leakage calculation module;

[0067] The average differential pressure between the primary air, secondary air and flue gas bin is calculated using the variable flow method; the average differential pressure corresponding to the primary air or secondary air is changed to obtain the leakage coefficient of the primary air leaking into the flue gas bin, the primary air leaking into the secondary air, and the secondary air leaking into the flue gas bin;

[0068] The correction module is used to calculate the temperature correction coefficient of the primary air and the secondary air using the temperature correction coefficient; combining the air leakage coefficient and the temperature correction coefficient, the air leakage of the primary air into the smoke bin, the primary air into the secondary air, and the secondary air into the smoke bin after correction is calculated;

[0069] The result output module is used to display the corrected leakage of primary air into the smoke bin, primary air into the secondary air, and secondary air into the smoke bin.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] 1) The present invention provides a method and system for calculating the air leakage of a three-compartment rotary air preheater. By acquiring relevant data on primary air, secondary air, and flue gas compartments and performing data cleaning, the accuracy and credibility of the data are improved, the accuracy of decision-making is enhanced, and the overall operation and maintenance efficiency is improved.

[0072] 2) The present invention provides a method and system for calculating the air leakage of a three-compartment rotary air preheater. The method calculates the air leakage of the primary air and the secondary air based on the mass balance equation, and carefully distinguishes the air leakage of the primary air into the flue gas bin and the secondary air, as well as the air leakage of the secondary air into the flue gas bin. This greatly improves the accuracy of the air leakage calculation, greatly enhances the pertinence and effectiveness of the air leakage control work, and improves the control ability of the air preheater leakage problem. In addition, the variable flow method is used to calculate the differential pressure between the primary air, secondary air and flue gas bin, and the air leakage coefficient of different parts is obtained by changing the differential pressure, which enhances the comprehensiveness of the analysis of the air preheater leakage situation and improves the stability and economy of the air preheater operation.

[0073] 3) The present invention provides a method and system for calculating the air leakage of a three-compartment rotary air preheater. The temperature correction coefficients of the primary and secondary air are calculated using the temperature correction coefficients, and the corrected air leakage is calculated in combination with the leakage coefficients. This improves the adaptability of the calculation results to the actual complex operating conditions and enhances the overall maintenance level of the air preheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a flow chart of a method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0075] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0076] The present invention provides the following technical solution: a method and system for calculating the air leakage of a three-compartment rotary air preheater.

[0077] See Figure 1 This embodiment provides a method for calculating the air leakage of a three-compartment rotary air preheater:

[0078] S1. Obtain relevant data of primary air, secondary air and smoke bin and perform pre-processing;

[0079] The relevant data include the flow rate, temperature, pressure and oxygen content of the primary air, secondary air and flue gas bin;

[0080] The preprocessing includes data cleaning and sampling window adjustment, specifically:

[0081] The data cleaning includes processing missing values, outliers and standardizing data formats;

[0082] The specific processing of outliers is to calculate the arithmetic mean of the relevant data, which is expressed as in represents the arithmetic mean, x i Represents the i-th related data, n represents the number of related data, and i represents the index value of the i-th related data; the relative deviation value between the current data and the arithmetic mean is expressed as Preset the deviation limit value. If the relative deviation value of the current data is greater than the deviation limit value, the current data will be eliminated from the relevant data;

[0083] The deviation limit value is selected in the range of 30%-40%;

[0084] The sampling window adjustment specifically includes adjusting the sampling window duration according to the current operation stability of the air preheater;

[0085] The rotary air preheater rotates once every 1 minute. If other conditions permit, the time it takes for the air preheater to rotate once is used as the sampling window length to average out data fluctuations caused by different resistances at various locations on the heat transfer elements of the air preheater.

[0086] Since the air preheater uses an asynchronous motor for rotation, the duration of its rotation cycle is not completely fixed. The sampling window duration can be adjusted regularly according to the actual situation. A more convenient method is to multiply the actual speed of the air preheater motor by the reducer ratio to obtain the actual speed of the air preheater, and use the actual speed of the air preheater to make real-time corrections. Alternatively, the correction value can be manually input according to the actual situation.

[0087] If the required sampling period is short, it can be divided into multiple equal or unequal time periods within one rotation period;

[0088] The method further includes calibrating the relevant data according to the calculation requirements;

[0089] S2. Calculate the primary and secondary air leakage online based on the mass balance equation and pre-processed relevant data;

[0090] The leakage of the primary air includes the leakage of the primary air into the smoke bin and the leakage of the primary air into the secondary air; the leakage of the secondary air includes the leakage of the secondary air into the smoke bin, which can be expressed as follows:

[0091] w p =w pin -w pout =w pg +w ps ;

[0092] w s =w sin -w sout =wsg -w ps ;

[0093] w g =w gin -w gout =w pg +w sg ;

[0094]

[0095] Where w p Indicates the primary air leakage volume; w s Indicates secondary air leakage; w g Indicates the air leakage of the flue gas bin;

[0096] w pin Indicates the primary air inlet flow rate; w sin Indicates the secondary air inlet flow rate; w gin Indicates the flow rate at the flue gas bin entrance; w pout Indicates the primary air outlet flow rate; w sout Indicates the secondary air outlet flow rate; w gout Indicates the outlet flow of the smoke bin; w pg Indicates the leakage of primary air into the flue gas bin; w ps Indicates the amount of air leakage from primary air into secondary air; w sg Indicates the amount of secondary air leaking into the flue gas bin;

[0097] S3. Use the variable flow method to calculate the average differential pressure between the primary air, secondary air and smoke bin, specifically:

[0098] The average differential pressure between the primary air and the smoke chamber is calculated online and expressed as:

[0099]

[0100] Where Δp pg Indicates the average differential pressure between the primary air and the smoke bin; p pin Indicates the primary air inlet pressure; p gout Indicates the outlet pressure of the flue gas chamber; p pout Indicates the primary air outlet pressure; p gin Indicates the inlet pressure of the flue gas silo;

[0101] The average differential pressure between the secondary air and the flue gas bin is calculated online and expressed as:

[0102]

[0103] Where Δp sg Indicates the average differential pressure between the secondary air and the flue gas chamber; p sinIndicates the secondary air inlet pressure; p sout Indicates the secondary air outlet pressure;

[0104] The average differential pressure between the primary air and the secondary air is calculated online and expressed as:

[0105]

[0106] Where Δp ps Indicates the average differential pressure between the primary and secondary air;

[0107] Among them, p pin 、p gout 、p pout 、p gin 、p sin and p sout The average value of the cross section during the test of the three-compartment rotary air preheater must be taken;

[0108] S4. Change the differential pressure corresponding to the primary air or secondary air to obtain the leakage coefficients of the primary air leaking into the smoke bin, the primary air leaking into the secondary air, and the secondary air leaking into the smoke bin;

[0109] S41. Change the differential pressure of the primary air to obtain the leakage coefficients of the primary air leaking into the flue gas bin and the primary air leaking into the secondary air;

[0110] S411. Adjust the primary air flow rate to keep the secondary air inlet pressure, air volume, and flue gas inlet pressure, air volume, etc. unchanged;

[0111] The differential pressure of the primary air to the smoke bin is extrapolated to zero, and the leakage of the secondary air into the smoke bin is separated; the leakage coefficient of the primary air into the smoke bin is calculated under the leakage test of the preset working conditions, and is expressed as follows:

[0112] w g,n =w pg,n +w sg ;

[0113]

[0114] Where k pg Indicates the leakage coefficient of primary air into the smoke bin; n indicates the index value of the nth working condition; w pg,n Indicates the air leakage into the flue gas bin under the nth working condition; Δp pg,n It represents the average differential pressure between the primary air and the smoke bin under the nth working condition;

[0115] Using the linear relationship between air leakage and the square root of the average differential pressure, the air leakage coefficient of the primary air leaking into the smoke bin is calculated using the formula: where w pg,n-1Indicates the air leakage into the flue gas bin under the n-1th working condition, Δp pg,n-1 Indicates the average differential pressure between the primary air and the smoke chamber under the n-1th working condition; the number of preset working conditions is 3-6;

[0116] In one embodiment, under different primary air pressures, the leakage of primary air into the smoke bin changes, but the pressure of secondary air on the smoke bin does not change, so the air volume of secondary air leaking into the smoke bin w sg No change, we can get w pg,n +w pg,n-1 =(w g,n -w sg )+(w g,n-1 -w sg )=w g,n +w g,n-1 -2w sg , and the leakage of secondary air into the smoke bin can be obtained by calculating the measuring device, that is, w sg Measurable, so we can get w pg,n +w pg,n-1 ;

[0117] In another embodiment, the leakage rate of the secondary air into the smoke bin is obtained by the graphical method. Specifically, since the square root of the average differential pressure is linearly related to the leakage rate, the graphical method is used to convert w g and As the horizontal and vertical axis coordinates respectively; w pg Extrapolate to 0, that is, At this time, the air leakage of the primary air into the smoke bin is 0, that is, the total air leakage of the smoke bin is equal to the air leakage of the secondary air into the smoke bin, so w g =w sg ;

[0118] In another embodiment, the leakage coefficient of primary air into the smoke bin is obtained by using the drawing method, specifically by converting w g and As the horizontal and vertical axis coordinates, the slope of the drawn curve is k pg ;

[0119] S412. Calculate the air leakage coefficient of the primary air into the secondary air, expressed as follows:

[0120]

[0121] Where k ps Indicates the air leakage coefficient of primary air leaking into secondary air;

[0122] S42. Change the differential pressure of the secondary air to obtain the leakage coefficient of the secondary air into the flue gas bin;

[0123] S421. Adjust the secondary air flow rate to keep the primary air inlet pressure, air volume, and flue gas inlet pressure, air volume, etc. unchanged;

[0124] The differential pressure of the secondary air to the smoke bin is extrapolated to zero, and the leakage of the primary air into the smoke bin is separated; the leakage coefficient of the secondary air into the smoke bin is calculated under the leakage test of the preset working conditions, and is expressed as follows:

[0125] w g,n =w pg +w sg,n ;

[0126]

[0127] Where k sg Indicates the leakage coefficient of secondary air into the flue gas bin; w sg,n Indicates the leakage of secondary air into the flue gas bin under the nth working condition; Δp sg,n It represents the average differential pressure between the secondary air and the flue gas bin under the nth working condition;

[0128] Using the linear relationship between air leakage and the square root of the average differential pressure, the air leakage coefficient of the secondary air leaking into the smoke bin is calculated as follows: where w sg,n-1 Indicates the leakage of secondary air into the flue gas bin under the n-1th working condition, Δp sg,n-1 Indicates the average differential pressure between the secondary air and the flue gas bin under the n-1th working condition; the number of preset working conditions is 4-6;

[0129] In one embodiment, under different secondary air pressures, the secondary air leakage into the smoke bin changes, but the pressure of the primary air on the smoke bin does not change, so the air volume of the primary air leakage into the smoke bin w pg No change, we can get w sg,n +w sg,n-1 =(w g,n -w pg )+(w g,n-1 -w pg )=w g,n +w g,n-1 -2w pg , and the air leakage into the smoke bin can be obtained by calculation, that is, w pg Measurable, so we can get w sg,n +w sg,n-1 ;

[0130] In another embodiment, the leakage rate of the primary air into the smoke bin is obtained by the graphical method. Specifically, since the square root of the average differential pressure is linearly related to the leakage rate, the graphical method is used to convert w g and As the horizontal and vertical axis coordinates respectively; w sgExtrapolate to 0, that is, At this time, the leakage of secondary air into the smoke bin is 0, that is, the total leakage of the smoke bin is equal to the leakage of secondary air into the smoke bin, so w g =w pg ;

[0131] In another embodiment, the leakage coefficient of primary air into the smoke bin is obtained by using the drawing method, specifically by converting w g and As the horizontal and vertical axis coordinates, the slope of the drawn curve is k sg ;

[0132] S422. Calculate the leakage coefficient of secondary air into the flue gas bin, expressed as follows:

[0133]

[0134] Where k sg Indicates the leakage coefficient of secondary air into the flue gas bin;

[0135] S5. When the temperature deviates from the set reference value calculated by calibration, the temperature correction of the primary air, secondary air and smoke bin is performed; the temperature correction coefficient of the primary air and secondary air is calculated using the temperature correction coefficient;

[0136] The temperature correction coefficient for calculating primary air leakage is expressed as follows:

[0137]

[0138] Where R p Indicates the temperature correction coefficient of primary air leakage; T p0in Indicates the primary air reference point inlet temperature; T p0out Indicates the primary air reference point outlet temperature; T pin Indicates the primary air inlet temperature; T pout Indicates the primary air outlet temperature;

[0139] The temperature correction coefficient for calculating secondary air leakage is expressed as follows:

[0140]

[0141] Where R s Indicates the temperature correction coefficient of secondary air leakage; T s0in Indicates the secondary air reference point inlet temperature; T s0out Indicates the secondary air reference point outlet temperature; T sin Indicates the secondary air inlet temperature; T sout Indicates the secondary air outlet temperature;

[0142] S6. Calculate the corrected air leakage of the primary air into the flue gas bin, the primary air into the secondary air, and the secondary air into the flue gas bin by combining the air leakage coefficient and the temperature correction coefficient;

[0143] The corrected leakage of primary air into secondary air is expressed as follows:

[0144]

[0145] Where A ps Indicates the leakage area ratio of primary air into secondary air; ρ a Indicates the air density;

[0146] The corrected leakage of primary air into the flue gas bin is expressed as follows:

[0147] Δp pg =Δp ps +p s -p g ;

[0148]

[0149] Where A pg Indicates the leakage area ratio of primary air into the flue gas bin;

[0150] The corrected leakage of secondary air into the flue gas bin is expressed as follows:

[0151]

[0152] Where A sg Indicates the leakage area ratio of secondary air into the flue gas bin;

[0153] S7. The method further includes a calculation method for determining the change in air leakage area, specifically, performing tests under low-load and high-load conditions; when under low-load conditions, reducing the primary air pressure or the secondary air pressure at the air preheater; when under high-load conditions, increasing the primary air pressure or the secondary air pressure at the air preheater, and always maintaining the primary air pressure or the secondary air pressure and the flue gas bin pressure stable; each time the primary air pressure is adjusted and stabilized for a preset period of time, obtaining data using a flow measurement device;

[0154] Calculate the changes in the corresponding air leakage coefficient and air leakage area of ​​primary air, secondary air and flue gas bin;

[0155] While keeping the primary air pressure and smoke bin pressure constant, change the secondary air pressure by changing the primary air pressure, and calculate the corresponding air leakage area ratios of the primary air, secondary air, and smoke bin;

[0156] Repeat the test change process. If the change range of the air leakage area exceeds the set threshold, it is judged that the sealing condition of the primary air or secondary air has deteriorated;

[0157] S8. The calculation of the corresponding air leakage area ratios of the primary air, secondary air and smoke bin is specifically as follows:

[0158] Obtain the corresponding air leakage areas of online primary air, secondary air and flue gas bin and the corresponding air leakage areas of primary air, secondary air and flue gas bin during calibration;

[0159] Calculate the air leakage area ratio during actual operation and calibration to obtain the corresponding air leakage area ratios of primary air, secondary air and flue gas bin, which can be expressed as:

[0160]

[0161]

[0162] Where A ps1 Indicates the leakage area ratio of online primary air into secondary air; A ps0 Indicates the leakage area ratio of primary air into secondary air during calibration; w ps1 Indicates the amount of air leakage from the online primary air into the secondary air; R p0 Indicates the temperature correction coefficient of primary air leakage during calibration; Δp ps0 Indicates the average differential pressure between the primary air and the secondary air during calibration; w ps0 Indicates the amount of air leakage from the primary air into the secondary air during calibration; R p1 Indicates the temperature correction coefficient of online primary air leakage; Δp ps1 Indicates the average differential pressure between the primary air and the secondary air on the line; A pg1 Indicates the leakage area ratio of online primary air into the flue gas bin; A pg0 Indicates the leakage area ratio of the primary air into the flue gas bin during calibration; w pg1 Indicates the amount of air leakage from the online primary air into the flue gas bin; Δp pg0 Indicates the average differential pressure between the primary air leaking into the flue gas bin during calibration; w pg0 Indicates the leakage of primary air into the flue gas bin during calibration; Δp pg1 Indicates the average differential pressure between the online primary air leaking into the flue gas bin; A sg1 Indicates the leakage area ratio of online secondary air into the flue gas bin; A sg0 Indicates the leakage area ratio of secondary air into the flue gas bin during calibration; w sg1 Indicates the amount of air leakage from the online secondary air into the flue gas bin; Δp sg0 Indicates the average differential pressure between the secondary air leaking into the flue gas bin during calibration; w sg0 Indicates the leakage of secondary air into the flue gas bin during calibration; Δp sg1Indicates the average differential pressure between the online secondary air leaking into the flue gas bin; R s1 Indicates the temperature correction coefficient of online secondary air leakage; R s0 Indicates the temperature correction coefficient of secondary air leakage during calibration.

[0163] In one embodiment, this embodiment further provides a system for calculating the air leakage of a three-compartment rotary air preheater, the system comprising a data acquisition module, an air leakage calculation module, a correction module, and a result output module, wherein:

[0164] The data acquisition module is used to acquire relevant data of primary air, secondary air and smoke bin, and perform preprocessing; and transmit the relevant data to the air leakage calculation module;

[0165] The air leakage calculation module is used to calculate the air leakage of primary air and secondary air online based on the mass balance equation and the relevant data after preprocessing; wherein the air leakage of primary air includes the air leakage of primary air into the smoke bin and the air leakage of primary air into the secondary air; the air leakage of secondary air includes the air leakage of secondary air into the smoke bin; the relevant data, the air leakage of primary air and secondary air are transmitted to the air leakage calculation module;

[0166] The average differential pressure between the primary air, secondary air and flue gas bin is calculated using the variable flow method; the average differential pressure corresponding to the primary air or secondary air is changed to obtain the leakage coefficient of the primary air leaking into the flue gas bin, the primary air leaking into the secondary air, and the secondary air leaking into the flue gas bin;

[0167] The correction module is used to calculate the temperature correction coefficient of the primary air and the secondary air using the temperature correction coefficient; combining the air leakage coefficient and the temperature correction coefficient, the air leakage of the primary air into the smoke bin, the primary air into the secondary air, and the secondary air into the smoke bin after correction is calculated;

[0168] The result output module is used to display the corrected leakage of primary air into the smoke bin, primary air into the secondary air, and secondary air into the smoke bin.

[0169] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for calculating the air leakage of a three-compartment rotary air preheater, characterized in that: The method comprises: Obtain relevant data of primary air, secondary air and flue gas silo and perform preprocessing; calculate the air leakage of primary air and secondary air online based on the mass balance equation and the relevant data after preprocessing; wherein the air leakage of primary air includes the air leakage of primary air into flue gas silo and the air leakage of primary air into secondary air; the air leakage of secondary air includes the air leakage of secondary air into flue gas silo; The average differential pressure between the primary air, secondary air and flue gas bin is calculated using the variable flow method; the average differential pressure corresponding to the primary air or secondary air is changed to obtain the leakage coefficient of the primary air leaking into the flue gas bin, the primary air leaking into the secondary air, and the secondary air leaking into the flue gas bin; The temperature correction coefficient is used to calculate the temperature correction coefficient of the primary air and the secondary air; the air leakage coefficient and the temperature correction coefficient are combined to calculate the corrected air leakage of the primary air into the flue gas bin, the primary air into the secondary air, and the secondary air into the flue gas bin.

2. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: The method further includes calibrating the relevant data according to the calculation requirements.

3. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: The air leakage of primary and secondary air is calculated online based on the mass balance equation and pre-processed relevant data, which can be expressed as follows: In p =in pin -In pout =in pg +in ps ; In s =in sin -In sout =in sg -In ps ; In g =in gin -In gout =in pg +in sg ; Where w p Indicates the primary air leakage volume; w s Indicates secondary air leakage; w g Indicates the air leakage volume of the smoke bin; w pin Indicates the primary air inlet flow rate; w sin Indicates the secondary air inlet flow rate; w gin Indicates the flow rate at the flue gas bin entrance; w pout Indicates the primary air outlet flow rate; w sout Indicates the secondary air outlet flow rate; w gout Indicates the outlet flow of the smoke bin; w pg Indicates the leakage of primary air into the flue gas bin; w ps Indicates the amount of air leakage from primary air into secondary air; w sg Indicates the amount of secondary air leaking into the flue gas bin.

4. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: The average differential pressure between the primary air and the smoke chamber is calculated online and expressed as: Where Δp pg Indicates the average differential pressure between the primary air and the smoke bin; p pin Indicates the primary air inlet pressure; p gout Indicates the outlet pressure of the flue gas chamber; p pout Indicates the primary air outlet pressure; p gin Indicates the inlet pressure of the flue gas silo; The average differential pressure between the secondary air and the flue gas bin is calculated online and expressed as: Where Δp sg Indicates the average differential pressure between the secondary air and the smoke bin; p sin Indicates the secondary air inlet pressure; p sout Indicates the secondary air outlet pressure; The average differential pressure between the primary air and the secondary air is calculated online and expressed as: Where Δp ps Indicates the average differential pressure between primary and secondary air.

5. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: By changing the differential pressure of the primary air, the leakage coefficients of the primary air leaking into the flue gas bin and the primary air leaking into the secondary air are obtained, specifically: The differential pressure of the primary air to the smoke bin is extrapolated to zero, and the leakage of the secondary air into the smoke bin is separated; the leakage coefficient of the primary air into the smoke bin is calculated under the leakage test of the preset working conditions, and is expressed as follows: In g,n =in pg,n +in sg ; Where k pg Indicates the leakage coefficient of primary air into the smoke bin; n indicates the index value of the nth working condition; w pg,n Indicates the air leakage into the flue gas bin under the nth working condition; Δp pg,n It represents the average differential pressure between the primary air and the smoke bin under the nth working condition; Calculate the air leakage coefficient of primary air into secondary air, expressed as follows: Where k ps Indicates the leakage coefficient of primary air into secondary air.

6. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: By changing the differential pressure of the secondary air, the leakage coefficient of the secondary air into the flue gas bin is obtained, specifically: The differential pressure of the secondary air to the smoke bin is extrapolated to zero, and the leakage of the primary air into the smoke bin is separated; the leakage coefficient of the secondary air into the smoke bin is calculated under the leakage test of the preset working conditions, and is expressed as follows: In g,n =in pg +in sg,n ; Where k sg Indicates the leakage coefficient of secondary air into the flue gas bin; w sg,n Indicates the leakage of secondary air into the flue gas bin under the nth working condition; Δp sg,n It represents the average differential pressure between the secondary air and the flue gas bin under the nth operating condition.

7. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: The temperature correction coefficients of primary and secondary air are calculated using the temperature correction coefficients, specifically: The temperature correction coefficient for calculating primary air leakage is expressed as follows: Where R p Indicates the temperature correction coefficient of primary air leakage; T p0in Indicates the primary air reference point inlet temperature; T p0out Indicates the primary air reference point outlet temperature; T pin Indicates the primary air inlet temperature; T pout Indicates the primary air outlet temperature; The temperature correction coefficient for calculating secondary air leakage is expressed as follows: Where R s Indicates the temperature correction coefficient of secondary air leakage; T s0in Indicates the secondary air reference point inlet temperature; T s0out Indicates the secondary air reference point outlet temperature; T sin Indicates the secondary air inlet temperature; T sout Indicates the secondary air outlet temperature; The corrected leakage of primary air into secondary air is expressed as follows: Where A ps Indicates the leakage area ratio of primary air into secondary air; ρ a Indicates the air density; The corrected leakage of primary air into the flue gas bin is expressed as follows: Δp pg =Δp ps +p s -p g ; Where A pg Indicates the leakage area ratio of primary air into the flue gas bin; The corrected leakage of secondary air into the flue gas bin is expressed as follows: Where A sg Indicates the leakage area ratio of secondary air into the flue gas bin.

8. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 1 is characterized in that: The method further includes conducting tests under low load and high load conditions; when under low load, reducing the primary air pressure or the secondary air pressure at the air preheater; when under high load, increasing the primary air pressure or the secondary air pressure at the air preheater; While keeping the primary air pressure and smoke bin pressure constant, change the secondary air pressure at least once, measure the data of the corresponding working conditions, and obtain the relevant data of the primary air, secondary air and smoke bin; While keeping the secondary air pressure and smoke bin pressure constant, change the primary air pressure at least once, measure the data of the corresponding working conditions, and obtain relevant data of the primary air, secondary air and smoke bin.

9. The method for calculating the air leakage of a three-compartment rotary air preheater according to claim 8, characterized in that: The calculation of the corresponding leakage area ratios of primary air, secondary air and smoke bin is specifically as follows: Under the initial working condition, the corresponding air leakage area ratio of primary air, secondary air and flue gas bin is 1; After a preset number of operating conditions, determine whether the air leakage has increased. If increased, calculate the air leakage coefficient and air leakage area based on the increased air leakage.

10. A system for calculating the air leakage of a three-compartment rotary air preheater, characterized in that: The system includes a data acquisition module, an air leakage calculation module, a correction module and a result output module, wherein: The data acquisition module is used to acquire relevant data of primary air, secondary air and smoke bin, and perform preprocessing; and transmit the relevant data to the air leakage calculation module; The air leakage calculation module is used to calculate the air leakage of primary air and secondary air online based on the mass balance equation and the relevant data after preprocessing; wherein the air leakage of primary air includes the air leakage of primary air into the smoke bin and the air leakage of primary air into the secondary air; the air leakage of secondary air includes the air leakage of secondary air into the smoke bin; the relevant data, the air leakage of primary air and secondary air are transmitted to the air leakage calculation module; The average differential pressure between the primary air, secondary air and flue gas bin is calculated using the variable flow method; the average differential pressure corresponding to the primary air or secondary air is changed to obtain the leakage coefficient of the primary air leaking into the flue gas bin, the primary air leaking into the secondary air, and the secondary air leaking into the flue gas bin; The correction module is used to calculate the temperature correction coefficient of the primary air and the secondary air using the temperature correction coefficient; combining the air leakage coefficient and the temperature correction coefficient, the air leakage of the primary air into the smoke bin, the primary air into the secondary air, and the secondary air into the smoke bin after correction is calculated; The result output module is used to display the corrected leakage of primary air into the smoke bin, primary air into the secondary air, and secondary air into the smoke bin.

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