CN109284581B - A method for analyzing the matching characteristics of working medium flow and heat load distribution on boiler heating surface - Google Patents

Abstract

The invention discloses a method for analyzing the matching characteristics of working medium flow and heat load distribution on the heating surface of a boiler, calculating the matching factor of the cooling working medium flow and heat load on the heating surface, grading the mismatching situation, and calculating the influence of each influencing factor on the matching factor. , according to the degree of influence, to analyze the mismatch between the cooling working fluid flow and heat load on the heating surface, and diagnose the significant factors that cause the mismatch between the cooling working fluid flow and heat load on the heating surface, so as to determine the boiler heating surface. The order in which mass flow and heat load distribution do not match. The invention can diagnose the controllable significant influencing factors, controllable semi-significant influencing factors and semi-controllable significant influences on the mismatch of the heating surface by analyzing the matching characteristics of the cooling medium flow distribution and the heat load distribution on the heating surface of the boiler. Factors, semi-controllable and semi-significant influencing factors, quickly and accurately determine the treatment order for the mismatch between the cooling medium flow distribution on the heating surface and the heat load distribution.

Description

A method for analyzing the matching characteristics of working medium flow and heat load distribution on boiler heating surface

technical field

The invention belongs to an analysis method for matching between a boiler heating surface and heat absorption, that is, heat load distribution with positive feedback characteristics, and particularly relates to a method for analyzing the matching characteristics of working medium flow and heat load distribution on a boiler heating surface.

Background technique

The superheater and reheater of the boiler and the water cooling wall of the once-through boiler have typical positive feedback characteristics. decrease, the outlet working fluid temperature is higher. In the design, the method of controlling the flow resistance coefficient of the heat exchange tube to match the heat absorption is adopted to make the temperature of the outlet working fluid basically the same, and there are often large differences in operation. At present, there are many analyses of the deviation of the outlet wall temperature distribution. However, there is no systematic method to express the degree of matching between the working fluid flow of the heating surface and the heat load, and there is no special method to diagnose the cause of the mismatch between the working fluid flow of the heating surface and the heat load.

At present, the large deviation of the wall temperature distribution at the outlet of the heating surface of the boiler is relatively prominent, which has a great impact on the operation safety of the heating surface of the boiler, such as causing the material of some heat exchange tubes to age too quickly, the oxide scale on the inner wall of some heat exchange tubes to grow too fast, and the The bonding state of the materials is not good, the water-cooled wall tube is pulled cracked, and the water-cooled wall tube has large-area transverse cracks. The reason for the large deviation of wall temperature distribution is that the cooling medium flow in the heat exchange tube does not match the heat absorption of the heat exchange tube. The factors that cause the mismatch are: the distribution of the resistance coefficient of the flow resistance of the heat exchange tube; the deviation of the heat absorption of different heat receiving tubes; Flue gas temperature and flue gas flow distribution in the furnace, that is, heat load distribution; coking and fouling on the surface of the heating surface; flue gas flow and temperature distribution changes caused by changes in boiler heat load; ratio of radiation heat transfer and convection heat transfer caused by heat load change; furnace flame temperature distribution change caused by boiler heat load change; furnace flame temperature distribution change caused by coal mill switching; static pressure distribution of inlet and outlet headers; steam-water system resistance coefficient distribution and theoretical deviation; orifice scaling Wait. The description of the matching characteristics of the cooling medium flow rate and the heat load in the heat exchange tube of the heating surface, as well as the steam fluctuation amplitude and rate in the process of variable load, the amplification effect of the wall temperature fluctuation compared with the steam temperature, etc. The changes of some of these factors are difficult to control and belong to uncontrollable factors; some factors can be changed and belong to controllable factors; some factors can be partially changed through adjustment and control and belong to semi-controllable factors.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for analyzing the matching characteristics of the flow rate of the working medium on the heating surface of the boiler and the distribution of the heat load, aiming at the deficiencies of the above-mentioned prior art.

In order to realize the above-mentioned technical purpose, the technical scheme adopted in the present invention is:

The method of analyzing the matching characteristics of working fluid flow and heat load distribution on the heating surface of the boiler, calculating the matching factor of the cooling working fluid flow and heat load on the heating surface, and classifying the mismatching situation; Classify to analyze the mismatch between the flow rate of the cooling medium and the heat load on the heating surface, diagnose the significant factors that cause the mismatch between the flow rate of the cooling medium and the heat load on the heating surface, so as to determine the flow of the working medium and the heat load on the heating surface of the boiler. Load distribution mismatch sequence, including the following steps:

Step 1: Test the outlet wall temperature distribution of the heating surface under different operating conditions;

Step 2: According to the boiler operating parameters and wall temperature distribution, calculate the working medium enthalpy rise distribution of each heat receiving tube;

Step 3: Statistical enthalpy rise distribution, calculate average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation; abnormal enthalpy rise concentration, maximum enthalpy rise migration, abnormal enthalpy rise distribution migration;

The formulas for calculating average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation; abnormal enthalpy rise concentration, maximum enthalpy rise migration, and abnormal enthalpy rise distribution migration are as follows:

Average enthalpy liters:

Standard enthalpy lift deviation:

Enthalpy lift deviation, that is, the difference between the heat exchange tube enthalpy lift and the average enthalpy lift: ΔH _ij =H _ij -H _p kJ/kg (3);

Maximum enthalpy lift deviation: ΔH _max =maxH _ij -H _p kJ/kg (4);

Relative maximum enthalpy lift deviation, that is, the ratio of the maximum enthalpy lift deviation to the average enthalpy lift: h _max =H _max /H _p (5);

Standard relative enthalpy lift deviation, that is, the ratio of heat exchange tube enthalpy lift deviation to standard enthalpy lift deviation: h _δ =H _p /δ _H (6);

The maximum standard enthalpy lift deviation, that is, the ratio of the maximum enthalpy lift deviation to the standard enthalpy lift deviation: h _δmax =H _max /δ _H (7);

Concentration degree of continuous abnormal enthalpy rise γ _i : For the tubes whose standard enthalpy rise deviation is greater than 3 times δ _H , the interval between two statistical points is considered to be continuous abnormal, and the percentage of continuous abnormal points in the statistical sample is called Concentration of continuous abnormal enthalpy rise, the formula is: γ _i =100×∑Cont(h _δ max>3)/N% (8);

Maximum enthalpy lift migration τ _kn : under working conditions k and n, the maximum enthalpy riser position migration statistical points, the percentage of the number of statistical samples is called the maximum enthalpy lift migration, the formula is: τ _kn = 100×( S(Hmax) ^k -S(Hmax) ⁿ )/N% (9);

Among them, S(Hmax) ^k is the position of the water wall tube with the largest enthalpy rise under the operating condition numbered k;

The center position Cen of the abnormal enthalpy rise point, that is, Cont(h _δ max>3) is the symmetrical center point of the continuous abnormal enthalpy rise distribution;

Abnormal enthalpy rise distribution migration τ _{γ kn} : the center position of abnormal enthalpy rise point of statistical continuous distribution, under working condition k and working condition n, the percentage of the number of statistical points migrated at the center point to the number of statistical samples is called abnormal enthalpy rise Distribution shift, the formula is: τ _γkn =100×(Cen ^k (Cont(h _δ max>3))−Cen ⁿ (Cont(h _δ max>3)))/N% (10).

Step 4: Use the statistical analysis method of weighting factor to calculate the matching factor of the cooling medium flow rate and the heat load on the heating surface; the matching factor is the matching between the cooling medium flow rate and the heat load on the heating surface, which is expressed by the enthalpy rise distribution of the heat exchange tube , denoted as ξ; the matching factor can be divided into single working condition matching factor and multi working condition matching factor, the multiple working condition matching factor ξ _ht ^k,n is the average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative enthalpy rise The function of maximum enthalpy rise deviation, standard maximum enthalpy rise deviation, abnormal enthalpy rise concentration, maximum enthalpy rise migration, and abnormal enthalpy rise distribution migration are calculated by the method of weighted statistics; the single condition matching factor ξ ^k only considers a single The matching characteristics under operating conditions are functions of average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation, standard maximum enthalpy rise deviation, and abnormal enthalpy rise concentration degree, which are also carried out by weighted statistics. The specific calculation formula is as follows:

ξ _ht ^k =f ₁ (H _p ,δ _H ,H _max ,h _max ,h _δmax ,γ _i )

=α ₁ ×H _p +α ₂ ×δ _H +α ₃ ×H _max +α ₄ ×h _max +α ₅ ×h _δmax +α ₆ ×γ _i (11);

ξ _ht ^k,n =f ₂ (H _p ,δ _H ,H _max ,h _max ,h _δmax ,γ _i ,τ _kn ,τ _γkn )=β ₁ ×(H _p -H _p )+β ₂ ×(δ ^k _H -δ ⁿ _H )+β ₃ ×(H ^k _max -H ⁿ _max )+β ₄ ×(h ^k _max -h ⁿ _max )+β ₅ ×(h ^k _δmax -h ⁿ _δmax )+β ₆ × (γ ^k _i -γ ⁿ _i )+β ₇ ×τ _kn +β ₈ ×τ _γkn (12), where α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ , β ₁ , β ₂ , β ₃ , β ₄ , β ₅ , β ₆ , β ₇ and β ₈ are weighting coefficients.

Step 5: Classify the matching characteristics of the cooling medium flow rate and heat load on the heating surface according to the calculated matching factor; the classification method is: given standard matching factors ξ ₀₁ , ξ ₀₂ , when the calculated heating surface matching factor ξ _ht > When ξ ₀₁ , it is a significant mismatch; when ξ ₀₂ >ξ _ht >ξ ₀₁ , it is a semi-significant mismatch; when ξ _ht <ξ ₀₂ , it is a match.

Step 6: Classify the factors that affect the matching characteristics of the cooling medium flow rate and the heat load on the heating surface; specifically, the factors affecting the cooling medium flow rate distribution are: heat exchange tube flow resistance coefficient, orifice diameter, inlet header static Pressure distribution, static pressure distribution of outlet header, boiler output, foreign matter blockage; factors that affect heat load distribution include: boiler output, furnace coking, heating area ash, coal mill commissioning, primary air uniformity, secondary air door adjustment , coal quality; the classification results are: non-controllable factors include: heat exchange tube flow resistance coefficient, inlet header static pressure distribution, outlet header static pressure distribution, coal quality; controllable factors include: grinding When the coal machine is put into use, the orifice diameter; the other factors are semi-controllable factors.

Step 7: Calculate the influence of factors on the matching factor of the cooling medium flow rate and heat load on the heating surface, and classify the influence degree of the factors; the classification method for the influence degree of the factors is: Calculate the controllable factor through different working conditions of the change of the influencing factors. The matching factor ξ _ht ^k,n of the cooling medium flow rate of the heating surface and the heat load of the factor and the semi-controllable factor, compared with the standard matching factors ξ _ef01 and ξ _ef02 , the influence of the factors on the matching factor is classified, ξ _ht ^k, When ⁿ >ξ _ef01 , it is a significant influencing factor; when ξ _ef02 >ξ _ht ^k,n >ξ _ef01 , it is a semi-significant influencing factor; when ξ _ht ^k,n <ξ _ef02 , it is a non-significant influencing factor.

Step 8: Classify the influencing factors; according to the controllable characteristics of the influencing factors and the degree of influence on the matching factor, the influencing factors are divided into: controllable significant influencing factors, semi-controllable significant influencing factors, and non-controllable factors. Significant influencing factors; controllable semi-significant influencing factors, semi-controllable semi-significant influencing factors, uncontrollable semi-significant influencing factors; non-significant influencing factors.

Step 9: The mismatch between the working medium flow and the heat load distribution on the heating surface of the boiler is controlled according to the controllable significant influencing factors, the controllable semi-significant influencing factors, the semi-controllable significant influencing factors, and the semi-controllable semi-significant influencing factors. , the remaining factors do not consider governance.

The present invention has the following beneficial effects:

The invention can diagnose the controllable significant influencing factors, controllable semi-significant influencing factors and semi-controllable significant influences on the mismatch of the heating surface by analyzing the matching characteristics of the cooling medium flow distribution and the heat load distribution on the heating surface of the boiler. factors, semi-controllable and semi-significant influencing factors, to determine the treatment order for the mismatch between the cooling medium flow distribution and the heat load distribution on the heating surface, the method is simple and effective, and the accuracy rate is high.

Detailed ways

The present invention will be further described in detail below with reference to specific embodiments.

The overall idea of the present invention is as follows: calculating the matching factor between the cooling medium flow rate and the heat load of the heating surface, and classifying the mismatched conditions; In this way, the mismatch between the flow rate of the cooling medium and the heat load on the heating surface is analyzed, and the significant factors that cause the mismatch between the flow rate of the cooling medium and the heat load on the heating surface are diagnosed.

In the embodiment, the method of the present invention is used to realize the analysis of the matching characteristics of the cooling medium flow rate and the furnace heat load of the once-through boiler water-cooled wall with a vertical water-cooled wall for the lower radiation, which specifically includes the following steps:

Step 1: Test the outlet wall temperature distribution of the heating surface under different operating conditions;

Step 2: According to the boiler operating parameters and wall temperature distribution, calculate the working medium enthalpy rise distribution of each heat receiving tube;

Step 3: Statistical enthalpy rise distribution, calculate average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation; abnormal enthalpy rise concentration, maximum enthalpy rise migration, abnormal enthalpy rise distribution migration;

The formulas for calculating average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation; abnormal enthalpy rise concentration, maximum enthalpy rise migration, and abnormal enthalpy rise distribution migration are as follows:

Average enthalpy liters:

Standard enthalpy lift deviation:

Enthalpy lift deviation, that is, the difference between the heat exchange tube enthalpy lift and the average enthalpy lift: ΔH _ij =H _ij -H _p kJ/kg (3);

Maximum enthalpy lift deviation: ΔH _max =maxH _ij -H _p kJ/kg (4);

Relative maximum enthalpy lift deviation, that is, the ratio of the maximum enthalpy lift deviation to the average enthalpy lift: h _max =H _max /H _p (5);

Standard relative enthalpy lift deviation, that is, the ratio of heat exchange tube enthalpy lift deviation to standard enthalpy lift deviation: h _δ =H _p /δ _H (6);

The maximum standard enthalpy lift deviation, that is, the ratio of the maximum enthalpy lift deviation to the standard enthalpy lift deviation: h _δmax =H _max /δ _H (7);

Concentration degree of continuous abnormal enthalpy rise γ _i : For the tubes whose standard enthalpy rise deviation is greater than 3 times δ _H , the interval between two statistical points is considered to be continuous abnormal, and the percentage of continuous abnormal points in the statistical sample is called Concentration of continuous abnormal enthalpy rise, the formula is: γ _i =100×∑Cont(h _δ max>3)/N% (8);

Maximum enthalpy lift migration τ _kn : under working conditions k and n, the maximum enthalpy riser position migration statistical points, the percentage of the number of statistical samples is called the maximum enthalpy lift migration, the formula is: τ _kn = 100×( S(Hmax) ^k -S(Hmax) ⁿ )/N% (9);

Among them, S(Hmax) ^k is the position of the water wall tube with the largest enthalpy rise under the operating condition numbered k;

The center position Cen of the abnormal enthalpy rise point, that is, Cont(h _δ max>3) is the symmetrical center point of the continuous abnormal enthalpy rise distribution;

Abnormal enthalpy rise distribution migration τ _{γ kn} : the center position of abnormal enthalpy rise point of statistical continuous distribution, under working condition k and working condition n, the percentage of the number of statistical points migrated at the center point to the number of statistical samples is called abnormal enthalpy rise Distribution shift, the formula is: τ _γkn =100×(Cen ^k (Cont(h _δ max>3))−Cen ⁿ (Cont(h _δ max>3)))/N% (10).

Step 4: Use the statistical analysis method of weighting factor to calculate the matching factor of the cooling medium flow rate and the heat load on the heating surface; the matching factor is the matching between the cooling medium flow rate and the heat load on the heating surface, which is expressed by the enthalpy rise distribution of the heat exchange tube , denoted as ξ; the matching factor can be divided into single working condition matching factor and multi working condition matching factor, the multiple working condition matching factor ξ _ht ^k,n is the average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative enthalpy rise The function of maximum enthalpy rise deviation, standard maximum enthalpy rise deviation, abnormal enthalpy rise concentration, maximum enthalpy rise migration, and abnormal enthalpy rise distribution migration are calculated by the method of weighted statistics; the single condition matching factor ξ ^k only considers a single The matching characteristics under operating conditions are functions of average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation, standard maximum enthalpy rise deviation, and abnormal enthalpy rise concentration degree, which are also carried out by weighted statistics. The specific calculation formula is as follows:

ξ _ht ^k =f ₁ (H _p ,δ _H ,H _max ,h _max ,h _δmax ,γ _i )

=α ₁ ×H _p +α ₂ ×δ _H +α ₃ ×H _max +α ₄ ×h _max +α ₅ ×h _δmax +α ₆ ×γ _i (11);

ξ _ht ^k,n =f ₂ (H _p ,δ _H ,H _max ,h _max ,h _δmax ,γ _i ,τ _kn ,τ _γkn )=β ₁ ×(H _p -H _p )+β ₂ ×(δ ^k _H -δ ⁿ _H )+β ₃ ×(H ^k _max -H ⁿ _max )+β ₄ ×(h ^k _max -h ⁿ _max )+β ₅ ×(h ^k _δmax -h ⁿ _δmax )+β ₆ × (γ ^k _i -γ ⁿ _i )+β ₇ ×τ _kn +β ₈ ×τ _γkn (12), where α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ , β ₁ , β ₂ , β ₃ , β ₄ , β ₅ , β ₆ , β ₇ and β ₈ are weighting coefficients.

Step 5: Classify the matching characteristics of the cooling medium flow rate and heat load on the heating surface according to the calculated matching factor; the classification method is: given standard matching factors ξ ₀₁ , ξ ₀₂ , when the calculated heating surface matching factor ξ _ht > When ξ ₀₁ , it is a significant mismatch; when ξ ₀₂ >ξ _ht >ξ ₀₁ , it is a semi-significant mismatch; when ξ _ht <ξ ₀₂ , it is a match.

Step 6: Classify the factors that affect the matching characteristics of the cooling medium flow rate and the heat load on the heating surface; specifically, the factors affecting the cooling medium flow rate distribution are: heat exchange tube flow resistance coefficient, orifice diameter, inlet header static Pressure distribution, static pressure distribution of outlet header, boiler output, foreign matter blockage; factors that affect heat load distribution include: boiler output, furnace coking, heating area ash, coal mill commissioning, primary air uniformity, secondary air door adjustment , coal quality; the classification results are: non-controllable factors include: heat exchange tube flow resistance coefficient, inlet header static pressure distribution, outlet header static pressure distribution, coal quality; controllable factors include: grinding When the coal machine is put into use, the orifice diameter; the other factors are semi-controllable factors.

Step 7: Calculate the influence of factors on the matching factor of the cooling medium flow rate and heat load on the heating surface, and classify the influence degree of the factors; the classification method for the influence degree of the factors is: Calculate the controllable factor through different working conditions of the change of the influencing factors. The matching factor ξ _ht ^k,n of the cooling medium flow rate of the heating surface and the heat load of the factor and the semi-controllable factor, compared with the standard matching factors ξ _ef01 and ξ _ef02 , the influence of the factors on the matching factor is classified, ξ _ht ^k, When ⁿ >ξ _ef01 , it is a significant influencing factor; when ξ _ef02 >ξ _ht ^k,n >ξ _ef01 , it is a semi-significant influencing factor; when ξ _ht ^k,n <ξ _ef02 , it is a non-significant influencing factor.

Step 8: Classify the influencing factors; according to the controllable characteristics of the influencing factors and the degree of influence on the matching factor, the influencing factors are divided into: controllable significant influencing factors, semi-controllable significant influencing factors, and non-controllable factors. Significant influencing factors; controllable semi-significant influencing factors, semi-controllable semi-significant influencing factors, uncontrollable semi-significant influencing factors; non-significant influencing factors.

Step 9: The mismatch between the working medium flow and the heat load distribution on the heating surface of the boiler is controlled according to the controllable significant influencing factors, the controllable semi-significant influencing factors, the semi-controllable significant influencing factors, and the semi-controllable semi-significant influencing factors. , the remaining factors do not consider governance.

The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions that belong to the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims (7)

1. A method for analyzing the matching characteristics of working fluid flow and heat load distribution on the heating surface of the boiler, which is characterized by: calculating the matching factor of the cooling working fluid flow and heat load on the heating surface, and grading the mismatched condition; calculating the matching factor of each influencing factor The influence of the heating surface is classified according to the degree of influence, so as to analyze the mismatch between the cooling medium flow rate and the heat load on the heating surface, and diagnose the significant factors that cause the mismatch between the cooling medium flow rate and the heat load on the heating surface. The order in which the surface working fluid flow does not match the heat load distribution includes the following steps: Step 1: Test the outlet wall temperature distribution of the heating surface under different operating conditions; Step 2: According to the boiler operating parameters and wall temperature distribution, calculate the working medium enthalpy rise distribution of each heat receiving tube; Step 3: Statistical enthalpy rise distribution, calculate average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation; abnormal enthalpy rise concentration, maximum enthalpy rise migration, abnormal enthalpy rise distribution migration; Step 4: Calculate the matching factor between the flow rate of the cooling working medium and the heat load on the heating surface by using the statistical analysis method of the weighting factor; Step 5: Classify the matching characteristics of the flow rate of the cooling working medium and the heat load on the heating surface according to the calculated matching factor; Step 6: Classify the factors that affect the matching characteristics of the cooling medium flow rate and heat load on the heating surface; Step 7: Calculate the influence of factors on the matching factor of the cooling medium flow rate and heat load on the heating surface, and classify the influence degree of the factors; Step 8: Classify the influencing factors; Step 9: The mismatch between the working medium flow and the heat load distribution on the heating surface of the boiler is controlled according to the controllable significant influencing factors, the controllable semi-significant influencing factors, the semi-controllable significant influencing factors, and the semi-controllable semi-significant influencing factors. , the remaining factors do not consider governance. 2. The method for analyzing the matching characteristics of boiler heating surface working fluid flow and heat load distribution according to claim 1, characterized in that: calculating average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise described in step 3 The enthalpy rise deviation; the formula of abnormal enthalpy rise concentration, maximum enthalpy rise migration, and abnormal enthalpy rise distribution migration are as follows: Average enthalpy liters:

Standard enthalpy lift deviation:

Enthalpy lift deviation, that is, the difference between the heat exchange tube enthalpy lift and the average enthalpy lift: ΔH _ij =H _ij -H _p kJ/kg (3); Maximum enthalpy lift deviation: ΔH _max =maxH _ij -H _p kJ/kg (4); Relative maximum enthalpy lift deviation, that is, the ratio of the maximum enthalpy lift deviation to the average enthalpy lift: h _max =H _max /H _p (5); Standard relative enthalpy lift deviation, that is, the ratio of heat exchange tube enthalpy lift deviation to standard enthalpy lift deviation: h _δ =H _p /δ _H (6); The maximum standard enthalpy lift deviation, that is, the ratio of the maximum enthalpy lift deviation to the standard enthalpy lift deviation: h _δmax =H _max /δ _H (7); Concentration degree of continuous abnormal enthalpy rise γ _i : For the tubes whose standard enthalpy rise deviation is greater than 3 times δ _H , the interval between two statistical points is considered to be continuous abnormal, and the percentage of continuous abnormal points in the statistical sample is called Concentration of continuous abnormal enthalpy rise, the formula is: γ _i =100×∑Cont(h _δ max>3)/N% (8); Maximum enthalpy lift migration τ _kn : under working conditions k and n, the maximum enthalpy riser position migration statistical points, the percentage of the number of statistical samples is called the maximum enthalpy lift migration, the formula is: τ _kn = 100×( S(Hmax) ^k -S(Hmax) ⁿ )/N% (9); Among them, S(Hmax) ^k is the position of the water wall tube with the largest enthalpy rise under the operating condition numbered k; The center position Cen of the abnormal enthalpy rise point, that is, Cont(h _δ max>3) is the symmetrical center point of the continuous abnormal enthalpy rise distribution; Abnormal enthalpy rise distribution migration τ _{γ kn} : Statistically continuous distribution of abnormal enthalpy rise point center position, under working condition k and working condition n, the percentage of statistical points migrated at the center point position to the number of statistical samples is called abnormal enthalpy rise Distribution shift, the formula is: τ _γkn =100×(Cen ^k (Cont(h _δ max>3))−Cen ⁿ (Cont(h _δ max>3)))/N% (10). 3. The method for analyzing the matching characteristics of the flow rate of the working medium on the heating surface of the boiler and the distribution of the heat load according to claim 2, it is characterized in that: the matching factor described in the step 4 is the matching between the flow rate of the cooling working medium and the heat load on the heating surface, using The enthalpy rise distribution of the heat exchange tube is expressed as ξ; the matching factor can be divided into a single working condition matching factor and a multi working condition matching factor, the multiple working condition matching factor ξ _ht ^k,n is the average enthalpy rise, the standard enthalpy rise The functions of deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation, standard maximum enthalpy rise deviation, abnormal enthalpy rise concentration, maximum enthalpy rise migration, and abnormal enthalpy rise distribution migration are calculated by the method of weighted statistics; The condition matching factor ξ ^k only considers the matching characteristics under a single operating condition, and is a function of the average enthalpy rise, standard enthalpy rise deviation, maximum enthalpy rise deviation, relative maximum enthalpy rise deviation, standard maximum enthalpy rise deviation, and abnormal enthalpy rise concentration. , and the method of weighted statistics is also used for calculation, and the specific calculation formula is as follows: ξ _ht ^k =f ₁ (H _p ,δ _H ,H _max ,h _max ,h _δmax ,γ _i ) =α ₁ ×H _p +α ₂ ×δ _H +α ₃ ×H _max +α ₄ ×h _max +α ₅ ×h _δmax +α ₆ ×γ _i (11); ξ _ht ^k,n =f ₂ (H _p ,δ _H ,H _max ,h _max ,h _δmax ,γ _i ,τ _kn ,τ _γkn )=β ₁ ×(H _p -H _p )+β ₂ ×(δ ^k _H -δ ⁿ _H )+β ₃ ×(H ^k _max -H ⁿ _max )+β ₄ ×(h ^k _max -h ⁿ _max )+β ₅ ×(h ^k _δmax -h ⁿ _δmax )+β ₆ × (γ ^k _i -γ ⁿ _i )+β ₇ ×τ _kn +β ₈ ×τ _γkn (12); In the formula, α ₁ , α ₂ , α ₃ , α ₄ , α ₅ , α ₆ , β ₁ , β ₂ , β ₃ , β ₄ , β ₅ , β ₆ , β ₇ and β ₈ are weighting coefficients. 4. The method for analyzing the matching characteristics of working fluid flow and heat load distribution on the heating surface of the boiler according to claim 3, wherein the grading method in step 5 is: given standard matching factors ξ ₀₁ , ξ ₀₂ , when calculating When the heating surface matching factor ξ _ht >ξ ₀₁ , it is a significant mismatch; when ξ ₀₂ >ξ _ht >ξ ₀₁ , it is a semi-significant mismatch; when ξ _ht <ξ ₀₂ , it is a match. 5. The method for analyzing the matching characteristics of the flow rate of the working medium on the heating surface of the boiler and the distribution of the heat load according to claim 4, characterized in that: the factors that affect the matching characteristics of the flow rate of the cooling working medium and the heat load on the heating surface described in step 6 are divided into: The factors affecting the flow distribution of cooling medium and the distribution of heat load, specifically, the factors affecting the flow distribution of cooling medium are: flow resistance coefficient of heat exchange tube, orifice diameter, static pressure distribution of inlet header, static pressure of outlet header, etc. Pressure distribution, boiler output, foreign matter blockage; factors affecting heat load distribution include: boiler output, furnace coking, heating area ash, coal mill commissioning, primary air uniformity, secondary air valve adjustment, and coal quality; The classification results are as follows: non-controllable factors include: heat exchange tube flow resistance coefficient, inlet header static pressure distribution, outlet header static pressure distribution, coal quality; controllable factors include: coal mill put into use, throttling Pore size; other factors are semi-controllable. 6. The method for analyzing the matching characteristics of the flow rate of the working medium on the heating surface of the boiler and the distribution of the heat load according to claim 5, wherein the method for grading the degree of influence of the factors described in step 7 is: through the different working conditions of the change of the influencing factors. Calculate the matching factor ξ _ht ^k,n of the cooling medium flow rate and heat load on the heating surface of the controllable factor and semi-controllable factor, compare with the standard matching factor ξ _ef01 and ξ _ef02 , and classify the influence of the factor on the matching factor , ξ _ht ^k,n >ξ _ef01 , it is a significant factor; when ξ _ef02 >ξ _ht ^k,n >ξ _ef01 , it is a semi-significant factor; when ξ _ht ^k,n <ξ _ef02 , it is non-significant influencing factors. 7. The method according to any one of claims 1-6 for analyzing the matching characteristics of the flow rate of the working medium on the heating surface of the boiler and the distribution of the heat load, characterized in that: the method for grading the influencing factors described in step 8 is as follows: The controllable characteristics and the degree of influence on the matching factor, the influencing factors are divided into: controllable significant influence factors, semi-controllable significant influence factors, non-controllable significant influence factors; controllable semi-significant influence factors, semi-significant influence factors Controllable semi-significant influencing factors, non-controllable semi-significant influencing factors; non-significant influencing factors.