JP5039606B2 - Corrosion rate estimation method for boiler heat transfer tubes - Google Patents

Description

  The present invention relates to a method for estimating the corrosion rate of a boiler heat transfer tube that estimates the corrosion rate at which the heat transfer tube corrodes and thins in a boiler facility using industrial waste as fuel, and in particular, heavy oil, waste tire, sludge The present invention relates to a method for estimating the corrosion rate of a boiler heat transfer tube, which can accurately estimate the corrosion rate even when using poor fuel such as wood chips and RDF.

  In general, in boiler equipment, fuel is burned in a furnace, and heat is recovered in a boiler from high-temperature combustion exhaust gas generated in the furnace. FIG. 10 shows an example of a boiler-equipped boiler facility. The fuel charged into the furnace 51 is burned in the furnace, and high-temperature combustion exhaust gas is generated. The combustion exhaust gas is sent to a boiler 52 provided in the furnace 51. The boiler 52 is provided with a heat exchanger 53 including a reheater, a secondary superheater, a primary superheater, a economizer, etc., and high-temperature combustion exhaust gas passing through the exhaust gas passage 54 in the boiler 52 and water supply Is heat-recovered from the combustion exhaust gas by exchanging heat through a boiler heat transfer tube. The combustion exhaust gas cooled by the boiler 52 is sent to a downstream exhaust gas treatment facility (not shown) as necessary.

In such boiler facilities, corrosion reduction of heat transfer tubes such as superheater tubes that are prone to corrosion is a problem, and in the worst case, it may lead to leakage trouble during operation. . In order to prevent this, it is necessary to accurately determine the corrosion thinning rate of the corresponding part and replace it at an appropriate timing.
Thus, as a method for obtaining corrosion thinning, for example, in Patent Document 1 (Japanese Patent Publication No. 1-16364), a method of estimating the amount of thinning of a pipe by measuring the length of a stud attached to a water pipe of a boiler. Is disclosed. An ultrasonic thickness meter is used to measure the length of the stud. As a result, the thickness of the pipe can be accurately measured and the corrosion state can be grasped, but this method can only be measured with the furnace stopped. Moreover, since the adhesion state of combustion ash that affects corrosion and the state of the flow of combustion gas are different from those of the water pipe main body, there is still a problem in terms of estimation accuracy.

Therefore, as another method, a method for estimating the corrosion rate using a corrosion estimation formula has been proposed and put into practical use. For example, the following corrosion estimation formula has been used in a waste power generation boiler facility.
ΔW = KLt (ΔW: thinning amount, KL: coefficient, t: time)
KL = Tg ^5.65 × Tm ^7.86 × HC ^l0.61 × C ^l0.37 × (Cr + Mo + Ni) ^-0.39 (1)
Tg: gas temperature, Tm: metal temperature, HCl: hydrochloric acid concentration in gas, Cl: chlorine concentration in gas
Cr, Mo, Ni: Concentrations of chromium, molybdenum and nickel in the material (steel), respectively.

Japanese Patent Publication No. 1-16364

As mentioned above, in order to operate the boiler equipment stably, it is necessary to accurately grasp the corrosion thinning of the furnace internals, especially heat transfer tubes that are prone to corrosion, and replace and maintain the heat transfer tubes at an appropriate timing. Need to do. However, the method of directly measuring the boiler heat transfer tube or the stud attached thereto has a problem that it can be measured only when the boiler is stopped. There is also a problem in terms of estimation accuracy.
Moreover, in the method of estimating the corrosion thinning from the corrosion rate estimation formula as shown in the above formula (1), the deviation from the thinning in the actual machine is large and is not practical. The reason for this is that the above corrosion rate estimation formula is originally intended for waste power generation boiler facilities that use waste as fuel, and there are many types such as gas temperature, metal temperature, hydrochloric acid concentration in gas, and chlorine concentration in gas. Therefore, if an error occurs in each measured value, the estimated thinning amount may cause a large difference from the actual thinning amount, and the corrosive components contained in the fuel. It is conceivable that accurate results cannot be obtained due to insufficient quantification.
Therefore, in view of the above-mentioned problems of the prior art, the present invention can estimate the corrosion rate of a boiler heat transfer tube that can accurately estimate the corrosion rate even when using poor fuels such as heavy oil, waste tires, and RDF. It aims to provide a method.

Therefore, in order to solve this problem, the present invention provides:
In a boiler facility for recovering heat in a heat exchanger from combustion exhaust gas generated by burning bad fuel, in a method for estimating the corrosion rate of a boiler heat transfer tube, the corrosion rate of the heat transfer tube included in the heat exchanger is estimated.
Based on the component analysis of the inferior fuel, a step of identifying a corrosive main element that is estimated to have the greatest influence on the corrosion of the heat transfer tube among components contained in at least one of the combustion exhaust gas and combustion ash;
Deriving a basic estimation formula of the corrosion rate based on the correlation between the concentration of the specified corrosion main element and the thinning rate of the heat transfer tube;
Obtaining measurement data including the heat transfer tube thickness of the boiler equipment, and setting a corrosion rate estimation formula in which the basic estimation formula is corrected according to the measurement data;
And a step of obtaining a corrosion rate of the heat transfer tube based on the corrosion rate estimation formula.

  According to the present invention, since the parameter in the corrosion rate estimation formula is only one of the main corrosion elements, the influence of measurement errors can be minimized. In addition, the corrosion rate estimation formula is corrected based on the measurement data of the actual machine with respect to the basic estimation formula of the corrosion rate derived based on the correlation between the corrosion main element concentration and the heat transfer tube thinning rate. The estimation accuracy can be improved.

Further, the second element of corrosion that is estimated to have the greatest influence on the corrosion of the heat transfer tube next to the main element of corrosion among the components contained in at least one of the combustion exhaust gas and combustion ash is identified and identified. Correspondingly convert the corrosion second element concentration to the corrosion main element concentration according to the degree of influence of the corrosion second element on the thinning rate, and correct the basic estimation formula by the corrosion main element concentration obtained by the conversion It is characterized by.
In this way, the corrosion rate estimation accuracy can be improved by equivalently converting the concentration of the second corrosion element affecting the corrosion to the concentration of the main corrosion element and correcting the basic estimation formula.
Furthermore, in addition to the main corrosion element, two or more corrosion factor elements that affect the corrosion of the heat transfer tube are selected from the components of the combustion exhaust gas, and the degree of influence of the selected corrosion factor elements on the thinning rate is selected. Accordingly, each corrosion factor element concentration is equivalently converted to a corrosion main element concentration, and the basic estimation formula is corrected by the corrosion main element concentration obtained by the conversion.
In this way, by selecting multiple corrosion-causing elements, equivalently converting to the concentration of main corrosion elements according to the degree of their influence, and correcting the basic estimation formula, the accuracy of corrosion rate estimation can be further improved. It becomes possible.

Furthermore, in the step of estimating the corrosion rate of the heat transfer tube, the concentration of the corrosion main element is calculated based on the component ratio of the inferior fuel input to the boiler equipment, and the concentration of the corrosion main element is calculated from the calculated concentration of the corrosion main element. The corrosion rate of the heat transfer tube is obtained based on the corrosion rate estimation formula,
An average concentration of the corrosion main element within a predetermined period is calculated, and a corrosion rate of the heat transfer tube is obtained from the average concentration.
This is because the amount of corrosive elements in the inferior fuel is not always constant, so that the estimation accuracy of the corrosion rate can be improved by using the average concentration of the main corrosive elements as described above.
At this time, it is preferable to calculate an equivalent amount of the corrosion main element and the corrosion second element and correct the basic estimation formula based on the equivalent amount.

Further, the heat exchanger is a superheater disposed in the boiler facility. Since the superheater has the most severe temperature and corrosion conditions among the heat transfer tubes installed in the boiler equipment, it is possible to grasp the status of other heat transfer tubes by estimating the corrosion rate of the superheater. .
Furthermore, the corrosion main element is chlorine. This is because the combustion exhaust gas that burns heavy fuel, waste tires, and bad fuels such as RDF often contains a large amount of chlorine, and the chlorine component has the highest influence on corrosion. It is possible to estimate the corrosion rate more accurately by using as the main corrosion element.
Furthermore, the corrosion second element is zinc. Thereby, it is possible to estimate the corrosion rate with higher accuracy.

As described above, according to the present invention, since the parameter in the corrosion rate estimation formula is only one of the main corrosion elements, the influence of measurement errors can be minimized. In addition, the corrosion rate estimation formula is corrected based on the measurement data of the actual machine with respect to the basic estimation formula of the corrosion rate derived based on the correlation between the corrosion main element concentration and the heat transfer tube thinning rate. The estimation accuracy can be improved.
Moreover, it is possible to improve the estimation accuracy of the corrosion rate by equivalently converting the concentration of the second corrosion element affecting the corrosion to the concentration of the main corrosion element and correcting the basic estimation formula.
Furthermore, it is possible to further increase the estimation accuracy of the corrosion rate by selecting multiple corrosion-causing elements, equivalently converting them to the concentration of major corrosion elements according to the degree of their influence, and correcting the basic estimation formula. Become.
Furthermore, the estimation accuracy of the corrosion rate can be improved by using the average concentration of the corrosion main element concentration.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
This embodiment is applied to boiler equipment fueled with crude fuel such as heavy oil, waste tires, sludge, wood chips, RDF, etc., and has a corrosion rate based on corrosion thinning of heat transfer tubes arranged in the boiler equipment. presume. Boiler equipment includes circulating fluidized bed boilers, bubbling fluidized bed boilers and other types of boiler equipment.

First, a circulating fluidized bed boiler facility will be described with reference to FIG. 9 as an example of an apparatus to which the corrosion rate estimation method of the present embodiment is applied.
As shown in FIG. 9, in the circulating fluidized bed boiler facility 1, in the fluidized bed furnace 2, after primary air is introduced from below and fluidized sand such as silica sand and poor fuel are fluidly mixed to perform primary combustion, Secondary air is introduced into the upper freeboard portion 2a to perform secondary combustion to complete combustion of the combustible gas, thereby generating high-temperature combustion gas. A cyclone 3 for separating combustion gas and fluidized sand is provided on the outlet side of the fluidized bed furnace 2 through a pipe 2b. A seal pot 5 is connected to the lower portion of the cyclone 3 via a pipe 4, and an external heat exchanger 8 is connected to the seal pot 5 via a pipe 7. The external heat exchanger 8 is connected to the fluidized bed furnace 2. It is connected to the lower part. The seal pot 5 is connected to the lower part of the fluidized bed furnace 2 through a pipe 6.

The upper part of the cyclone 3 is connected to the boiler 10 via the combustion exhaust gas passage 9. The boiler 10 is provided with a plurality of heat exchangers 11 and 12 including a reheater, a secondary superheater, a primary superheater, a economizer, and the combustion exhaust gas passing through the boiler 10 is a heat exchanger. Heat is recovered by exchanging heat with water supplied to 11 and 12.
This embodiment is used when estimating the corrosion rates of the heat exchangers 11 and 12 and the external heat exchanger 8, and is preferably used for a superheater provided in a combustion exhaust gas atmosphere of 400 ° C or higher.

Moreover, in this embodiment, the arithmetic device 20 in which the program which performs the various arithmetic processing regarding estimation of a corrosion rate was stored is provided. The arithmetic device 20 performs arithmetic processing according to the processing flow shown in the first to third embodiments described later. Moreover, the arithmetic unit 20 includes a storage unit 21, and the corrosion rate estimation formula set by the arithmetic unit 20 is stored in the storage unit 21.
Furthermore, at least one of the concentration calculation means 31 and the density | concentration detection means 32 which acquire the predetermined component density | concentration contained in at least any one of combustion exhaust gas and combustion ash is provided. The concentration calculation means 31 performs a component analysis of the inferior fuel introduced into the fluidized bed furnace 2 and is included in at least one of combustion exhaust gas and combustion ash generated when the fuel is burned based on the analysis result. It is means for obtaining the predetermined component concentration. The concentration detection means 32 is means for directly measuring combustion exhaust gas or combustion ash and detecting the predetermined component concentration.

  Referring to FIG. 1, in the corrosion rate estimation method of the first embodiment, first, a corrosion main element estimated to have the greatest influence on the corrosion of the heat transfer tube is specified (S11). This is to analyze the main fuel used in each plant, determine the component and amount of at least one of the combustion exhaust gas generated when the fuel is burned and the combustion ash contained in the combustion exhaust gas, Should be specified. Preferably, the main corrosion element is chlorine. This is because a large amount of chlorine is often contained in combustion exhaust gas and combustion ash obtained by burning heavy fuel, waste tires, RDF and other poor fuels, and the chlorine component has the highest influence on corrosion. By using this as the main element of corrosion, it is possible to estimate the corrosion rate more accurately.

  Then, a basic estimation formula for the corrosion rate is derived based on the correlation between the specified concentration of the main corrosion element and the thinning rate of the heat transfer tube (S12). The correlation between the corrosion main element concentration and the heat transfer tube thinning rate is represented by, for example, a curve shown in FIG. This correlation is obtained by graphing the thinning rate of the heat transfer tube when the concentration of the main corrosion element is changed using a test apparatus that simulates an actual machine. At this time, when it is contained in the gas, when it is contained in the adhering ash, in both cases, the test may be performed according to the corrosive environment of the actual machine. The material is preferably the same as that used in the actual machine.

Next, actual machine measurement data including the heat transfer tube wall thickness of the boiler equipment is acquired, and a corrosion rate estimation formula obtained by correcting the basic estimation formula is set according to the measurement data (S13). This is because the correlation coefficient term with the actual machine is added to the basic estimation formula, the correlation coefficient is obtained from the actual machine measurement data after a certain period of operation, and the correlation coefficient is applied to the correlation coefficient term to estimate the corrosion rate. Let it be an expression.
FIGS. 1B and 1C show corrosion rate estimation formulas obtained by correcting the basic estimation formula with actual machine measurement data. FIG. 1 (b) shows the corrosion rate estimation formula when the thinning rate is increased from the basic estimation formula by correcting the actual machine measurement data, and (c) shows the corrosion rate estimation formula when the thinning rate is reduced. Show.
By applying the corrosion main element concentration of the actual machine to the corrosion rate estimation formula set as described above, the corrosion rate of the actual machine is estimated (S14), and the corrosion thinning amount at the assumed time is calculated. The corrosion main element concentration of the actual machine is acquired by the concentration calculation means 31 or the concentration detection means 32 in FIG.

  According to the first embodiment, since the parameter in the corrosion rate estimation formula is only one of the main corrosion elements, the influence of measurement errors can be minimized. In addition, the corrosion rate estimation formula is corrected based on the measurement data of the actual machine with respect to the basic estimation formula of the corrosion rate derived based on the correlation between the corrosion main element concentration and the heat transfer tube thinning rate. The estimation accuracy can be improved.

The table | surface which evaluated the thinning estimation precision in the two plants A and B using the present Example 1 is shown in FIG. In the figure, the existing formula shows a value calculated by a conventional corrosion rate estimation formula (see formula (1)), and the basic estimation formula and the corrosion rate estimation formula both have values calculated by the formula shown in the first embodiment. Show.
Note that the estimated accuracy value = (thickening amount of actual machine) / (thinning amount obtained from the estimation formula).
As shown in FIG. 2, the value estimated by the corrosion rate estimation formula shown in Example 1 has the highest accuracy, and the accuracy can be improved by a factor of about two compared to the case where the conventional estimation formula is used. It was.

In the second embodiment, another correction means is added to the estimation method of the first embodiment described above. As shown in FIG. 3, first, in the same manner as in Example 1, the main corrosion element estimated to have the greatest influence on the corrosion of the heat transfer tube is specified (S11), and the concentration of the specified main corrosion element and the reduction of the heat transfer tube are identified. Based on the correlation with the meat speed, a basic estimation formula for the corrosion rate is derived (S12).
Further, a corrosion second element estimated to have the greatest influence on the corrosion of the heat transfer tube is identified next to the main corrosion element among the components contained in at least one of the combustion exhaust gas and combustion ash, and the identified corrosion second The corrosion second element concentration is equivalently converted to the corrosion main element concentration according to the degree of influence of the element on the thinning rate, and the basic estimation formula is corrected by the corrosion main element concentration obtained by the conversion (S15). The identification of the corrosion second element is specified in the same manner as the corrosion main element. The corrosion second element is preferably zinc.

In the equivalent conversion of the corrosion second element concentration, the equivalent coefficient α is experimentally obtained by a test apparatus, and the corrosion second element concentration is converted into the corrosion main element concentration by this equivalent coefficient. And the corrosion main element equivalent density | concentration is computed by following formula (2). In the formula (2), the main corrosion element is chlorine (Cl), and the second corrosion element is zinc (Zn).
Cl ^* = [% Cl] + α [% Zn] (2)
Here, Cl ^* is a corrosion main element equivalent concentration, [% Cl] is a corrosion main element concentration, and [% Zn] is a corrosion second element concentration.

Next, a basic estimation formula showing a correlation between the concentration of the corrosion main element and the concentration of the corrosion second element and the corrosion rate is derived by a test including the corrosion second element. When this is contained in the gas, when it is contained in the adhering ash, it is preferable to carry out the test according to the corrosive environment of the actual machine, as in the case of both. From this, the equivalent concentration of the main corrosion element is obtained. The material is the same as that used for the actual machine. The basic estimation formula corrected by the corrosion second element is shown in FIG.
And like Example 1, after acquiring actual machine measurement data including the heat transfer tube thickness of boiler equipment, and setting the corrosion rate estimation formula which corrected the basic estimation formula according to this measurement data (S13), The corrosion rate of the actual machine is estimated by applying the corrosion main element concentration of the actual machine to this corrosion rate estimation formula (S14), and the corrosion thinning amount at the assumed time is calculated.

Like Example 2, the concentration of the corrosion second element that affects the corrosion is equivalently converted to the concentration of the main corrosion element, and the basic estimation formula is corrected to improve the estimation accuracy of the corrosion rate. .
Furthermore, in the second embodiment, the corrosion second element that affects the corrosion is considered, but the third element, the fourth element,... And two or more corrosion factor elements are selected, and the basic estimation is performed based on these elements. The equation may be corrected. In this case, the concentration of each corrosion factor element is equivalently converted to the corrosion main element concentration according to the degree of influence of the selected plurality of corrosion factor elements on the metal thinning rate, and the basic value is determined based on the corrosion main element concentration obtained by the conversion. Correct the estimation formula. Thereby, it is possible to further increase the estimation accuracy of the corrosion rate.
The table | surface which evaluated the thinning estimation accuracy using the present Example 2 is shown in FIG. As shown in the figure, the value using the corrosion rate estimation formula of Example 2 is the most accurate, and the accuracy can be improved by a factor of about 2 compared to the case using the conventional estimation formula. .

In the third embodiment, the corrosion rate is calculated using the average concentration with respect to the estimation method of the first embodiment. This is because the amount of corrosive elements in the poor fuel is not always constant, so that the estimation accuracy is improved by using the average concentration in the corrosion rate estimation formula.
The calculation method of the corrosion main element average concentration is shown below.
The amount of main elements of corrosion of various fuels to be used is grasped in advance. This can be obtained by analyzing gas concentration, ash concentration, etc. according to the corrosive environment. Next, the average main element concentration during the period is calculated from the ratio of the amount of various fuels used until the estimation of the amount of corrosion (total operation time).
Then, the corrosion rate is calculated by applying the above average main element concentration to the corrosion rate estimation formula obtained in Example 1, and the corrosion thinning amount at the assumed time is calculated. Corrosion rate estimation formulas corrected by the average concentration of corrosion main elements are shown in FIGS. 5 (e) and 5 (f), for example.

According to the present embodiment, it is possible to improve the estimation accuracy of the corrosion rate by using the average concentration of the corrosion main element concentration.
FIG. 6 shows a table in which the thinning estimation accuracy is evaluated in each plant A and plant B using the third embodiment. As shown in the figure, the value using the corrosion rate estimation formula of Example 3 has the highest accuracy, and the accuracy can be improved by about 2 to 3 times compared to the case using the conventional estimation formula. It was.

Furthermore, in the third embodiment, it is preferable to perform calculation using the equivalent amounts of the main corrosion element and the second corrosion element in the corrosion rate estimation formula.
The calculation method of the equivalent amount in the case of handling the corrosion second element is shown below.
The amount of main elements of corrosion of various fuels to be used is grasped in advance. This can be obtained by analyzing gas concentration, ash concentration, etc. according to the corrosive environment.
Next, using a test apparatus that simulates an actual machine, the correlation coefficient between the corrosion main element and the corrosion second element affecting the corrosion is grasped and expressed in the form of an equivalent amount of the corrosion main element. This test is carried out with materials equivalent to those used for actual equipment.
The average concentration of major element equivalents during the period is calculated based on the amount of fuel used up to the time of corrosion estimation (total operation time). Then, the above-mentioned main element equivalent amount average concentration is applied to the corrosion rate estimation formula obtained in Example 1 to obtain the corrosion rate, and the corrosion thinning amount is calculated. For example, FIG. 7 shows an equation corrected by the principal element equivalent amount average concentration in consideration of the second element.

According to the present embodiment, it is possible to improve the estimation accuracy of the corrosion rate by calculating the equivalent coefficient of the corrosion second element to the corrosion main element and expressing the relationship with the thinning rate by the average concentration of the equivalent amount of the main element. It becomes.
The table | surface which evaluated the thinning estimation precision of the plant A using the said structure is shown in FIG. As shown in the figure, the value using the corrosion rate estimation formula of this configuration has the highest accuracy, and the accuracy can be further improved as compared with the case where the conventional estimation formula is used.

It is a figure explaining the corrosion rate estimation method which concerns on Example 1 of this invention. It is a table | surface which compares the corrosion estimation precision in Example 1. FIG. It is a figure explaining the corrosion rate estimation method which concerns on Example 2 of this invention. It is a table | surface which compares the corrosion estimation precision in Example 2. FIG. It is a figure concerning the Example 3 of this invention, and represents the corrosion rate estimation formula which carried out average density | concentration correction | amendment. It is a table | surface which compares the corrosion estimation precision in Example 3. FIG. In addition to FIG. 5, it is a figure showing the corrosion rate estimation formula which carried out 2nd element equivalent correction | amendment. It is a table | surface which compares the corrosion estimation precision in Example 3. FIG. It is a schematic block diagram which shows the boiler equipment with which embodiment of this invention is applied. The schematic block diagram of the conventional boiler equipment is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circulating fluidized bed boiler equipment 2 Fluidized bed furnace 2b 4, 6, 7 Piping 3 Cyclone 5 Seal pot 8 External heat exchanger 10 Boiler 11, 12 Heat exchanger 20 Arithmetic device 21 Memory | storage part 31 Concentration calculation means 32 Concentration detection means 51 Furnace 52 Boiler 53 Heat exchanger 54 Exhaust gas passage

Claims (7)

In a boiler facility for recovering heat in a heat exchanger from combustion exhaust gas generated by burning bad fuel, in a method for estimating the corrosion rate of a boiler heat transfer tube, the corrosion rate of the heat transfer tube included in the heat exchanger is estimated.
Based on the component analysis of the inferior fuel, a step of identifying a corrosive main element that is estimated to have the greatest influence on the corrosion of the heat transfer tube among components contained in at least one of the combustion exhaust gas and combustion ash;
Deriving a basic estimation formula of the corrosion rate based on the correlation between the concentration of the specified corrosion main element and the thinning rate of the heat transfer tube;
Obtaining measurement data including the heat transfer tube thickness of the boiler equipment, and setting a corrosion rate estimation formula in which the basic estimation formula is corrected according to the measurement data;
And a step of obtaining a corrosion rate of the heat transfer tube based on the corrosion rate estimation formula.   Of the components contained in at least one of the combustion exhaust gas and combustion ash, a second corrosion element that is estimated to have the greatest effect on the corrosion of the heat transfer tube is identified next to the main corrosion element, and the identified corrosion second The second element concentration of corrosion is equivalently converted to the concentration of major corrosion elements according to the degree of influence of the two elements on the thinning rate, and the basic estimation formula is corrected by the concentration of major corrosion elements obtained by the conversion. The method for estimating the corrosion rate of a boiler heat transfer tube according to claim 1.   Among the components of the combustion exhaust gas, in addition to the main corrosion element, two or more corrosion factor elements that affect the corrosion of the heat transfer tube are selected, and the selected corrosion factor element is selected according to the degree of influence on the thinning rate. The corrosion of a boiler heat transfer tube according to claim 1, wherein each corrosion factor element concentration is equivalently converted to a corrosion main element concentration, and the basic estimation formula is corrected by the corrosion main element concentration obtained by the conversion. Speed estimation method. In the step of estimating the corrosion rate of the heat transfer tube, the concentration of the corrosion main element is calculated based on the component ratio of the inferior fuel input to the boiler equipment, and the corrosion rate is estimated from the calculated concentration of the corrosion main element. Based on the equation, the corrosion rate of the heat transfer tube is obtained,
The corrosion rate estimation of a boiler heat transfer tube according to any one of claims 1 to 3, wherein an average concentration of the corrosion main element within a predetermined period is calculated, and a corrosion rate of the heat transfer tube is obtained from the average concentration. Method.   The said heat exchanger is a superheater arrange | positioned at the said boiler installation, The corrosion rate estimation method of the boiler heat exchanger tube in any one of the Claims 1 thru | or 4 characterized by the above-mentioned.   6. The method for estimating a corrosion rate of a boiler heat transfer tube according to claim 1, wherein the main corrosion element is chlorine.   The said corrosion 2nd element is zinc, The corrosion rate estimation method of the boiler heat exchanger tube in any one of Claim 1 thru | or 6 characterized by the above-mentioned.

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