Heat transfer surface evaluation device, control device, heat transfer surface evaluation method, and heat transfer surface management method

Abstract

To accurately estimate an inlet-side combustion gas temperature of a heat transfer surface.SOLUTION: A combustion gas temperature estimation device estimates a temperature of a combustion gas to be supplied to at least one heat transfer surface to exchange heat with vapor. The device calculates an enthalpy change amount of the combustion gas on the heat transfer surface on the basis of a heat absorption amount of the steam on the heat transfer surface and a flow rate of the combustion gas and adds the enthalpy change amount to enthalpy corresponding to an outlet-side combustion gas temperature, thus calculating inlet-side combustion gas enthalpy of the combustion gas at an inlet side of the heat transfer surface. An inlet-side combustion gas temperature of the heat transfer surface is calculated on the basis of the calculated inlet-side combustion gas enthalpy.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a combustion gas temperature estimation device, a heat transfer surface evaluation device, a control device, a combustion gas temperature estimation method, a heat transfer surface evaluation method, and a heat transfer surface management method. [Background technology]

[0002] Boilers are known that can generate steam by heat exchange with combustion gases generated by burning fuel such as coal through heat transfer surfaces. The combustion gases generated in the boiler furnace are guided from the furnace outlet to a downstream economizer through a combustion gas flow path. The combustion gas flow path is provided with multiple heat transfer surfaces along the flow direction of the combustion gas, and steam is generated by heat exchange with these heat transfer surfaces.

[0003] In order to evaluate the heat transfer state of a boiler, the inlet combustion gas temperature at each heat transfer surface provided in the combustion gas flow path is sometimes measured. Since it may be difficult to measure the inlet combustion gas temperature at each heat transfer surface using a general temperature sensor when the combustion gas temperature is high, for example, Patent Document 1 discloses a method for estimating the inlet combustion gas temperature at each upstream heat transfer surface based on the inlet combustion gas temperature of a downstream economizer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-280703 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the inlet combustion gas temperature of each upstream heat transfer surface is estimated based on the inlet combustion gas temperature of the downstream economizer, but the estimation is calculated based on the specific heat and temperature without considering the pressure of the combustion gas or steam. Because the inlet combustion gas temperature of each heat transfer surface depends on the pressure of the combustion gas or steam, it is difficult to accurately estimate it using a simple method like Patent Document 1.

[0006] At least one embodiment of the present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a combustion gas temperature estimation device, a heat transfer surface evaluation device, a control device, a combustion gas temperature estimation method, a heat transfer surface evaluation method, and a heat transfer surface management method that are capable of accurately estimating the inlet-side combustion gas temperature of a heat transfer surface. [Means for solving the problem]

[0007] In order to solve the above problem, the combustion gas temperature estimation device according to at least one embodiment of the present disclosure includes: (1) A combustion gas temperature estimation device according to one aspect includes: A combustion gas temperature estimation device for estimating a temperature of combustion gas supplied to at least one heat transfer surface for performing heat exchange with steam, comprising: an outlet-side combustion gas temperature acquisition unit for acquiring an outlet-side combustion gas temperature of the heat transfer surface; a combustion gas flow rate acquisition unit for acquiring a flow rate of the combustion gas; a steam heat absorption amount calculation unit for calculating the amount of heat absorption of the steam on the heat transfer surface; an enthalpy change calculation unit for calculating an enthalpy change of the combustion gas on the heat transfer surface based on the amount of heat absorbed and the flow rate of the combustion gas; an inlet-side combustion gas enthalpy calculation unit for calculating an inlet-side combustion gas enthalpy of the combustion gas at the inlet side of the heat transfer surface by adding the enthalpy change amount to the enthalpy corresponding to the outlet-side combustion gas temperature; an inlet-side combustion gas temperature calculation unit for calculating an inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy; Equipped with.

[0008] In order to solve the above problem, a heat transfer surface evaluation device according to at least one embodiment of the present disclosure includes: a combustion gas temperature estimation device according to at least one embodiment of the present disclosure; an effective heat transfer area calculation unit for calculating an effective heat transfer area of ​​the heat transfer surface based on the inlet-side combustion gas temperature, the outlet-side combustion gas temperature, the inlet-side steam temperature, the outlet-side steam temperature, and the amount of heat absorption; Equipped with.

[0009] In order to solve the above problem, a control device according to at least one embodiment of the present disclosure includes: a heat transfer surface evaluation device according to at least one embodiment of the present disclosure; a control unit for controlling a soot blower for removing soot from the heat transfer surface based on the effective heat transfer area; Equipped with.

[0010] In order to solve the above problem, a combustion gas temperature estimation method according to at least one embodiment of the present disclosure includes: 1. A combustion gas temperature estimation method for estimating a temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam, comprising: acquiring a combustion gas temperature at an outlet side of the heat transfer surface; obtaining a flow rate of the combustion gas; calculating the amount of heat absorbed by the steam on the heat transfer surface; calculating an enthalpy change amount of the combustion gas on the heat transfer surface based on the amount of heat absorbed and the flow rate of the combustion gas; calculating an inlet-side combustion gas enthalpy of the combustion gas at the inlet side of the heat transfer surface by adding the enthalpy change amount to the enthalpy corresponding to the outlet-side combustion gas temperature; calculating an inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy; Equipped with.

[0011] In order to solve the above problem, a heat transfer surface evaluation method according to at least one embodiment of the present disclosure includes: The inlet-side combustion gas temperature, the outlet-side combustion gas temperature, and the inlet-side steam temperature of the heat transfer surface estimated by the combustion gas temperature estimation method according to at least one embodiment of the present disclosure, Heat transfer surface and calculating an effective heat transfer area of ​​the heat transfer surface based on the outlet side steam temperature and the amount of heat absorption. [Effects of the Invention]

[0012] According to at least one embodiment of the present disclosure, it is possible to provide a combustion gas temperature estimation device, a heat transfer surface evaluation device, a control device, a combustion gas temperature estimation method, a heat transfer surface evaluation method, and a heat transfer surface management method that are capable of accurately estimating the inlet-side combustion gas temperature of a heat transfer surface. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating a simplified configuration of a boiler according to an embodiment. [Figure 2] 1 is a block diagram showing a configuration of a combustion gas temperature estimation device according to an embodiment; [Figure 3] FIG. 2 is a schematic diagram illustrating the vicinity of the heat transfer surface of FIG. 1. [Figure 4] 3 is a flowchart illustrating a combustion gas temperature estimation method according to one embodiment. [Figure 5] 1 is a block diagram showing the configuration of a heat transfer surface evaluation device according to an embodiment. [Figure 6] This is a modification of FIG. [Figure 7] 7 is a characteristic graph showing the relationship between the correction value calculated by the correction unit in FIG. 6 and the inlet-side combustion gas temperature calculated by the combustion gas temperature estimation device. [Figure 8] FIG. 2 is a block diagram showing a configuration of a control device according to an embodiment. [Figure 9] 10 shows verification results showing the transition of the effective heat transfer area on a heat transfer surface. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, several embodiments will be described with reference to the accompanying drawings. However, the configurations described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention.

[0015] (Boiler configuration) First, the configuration of a boiler that handles combustion gas that is the estimation target of a combustion gas temperature estimation device according to at least one embodiment of the present disclosure will be described. Fig. 1 is a schematic diagram showing a simplified configuration of a boiler 1 according to one embodiment.

[0016] The boiler 1 has a combustion gas flow path 2 through which combustion gas generated in an upstream furnace (not shown) flows. At least one heat transfer surface 4 is provided in the combustion gas flow path 2 along the flow direction of the combustion gas. The combustion gas flow path 2 may be provided with multiple heat transfer surfaces 4, and in the example of FIG. 1, it includes a first heat transfer surface 4a and a second heat transfer surface 4b located upstream of the first heat transfer surface 4a. These heat transfer surfaces 4 enable heat exchange between the combustion gas flowing through the combustion gas flow path 2 and the steam flowing through the steam flow path 6. In addition, on the downstream side of the combustion gas flow path 2, for example, a fuel economizer is disposed.

[0017] A combustion gas temperature sensor 8 for detecting the temperature of the combustion gas is provided downstream of the heat transfer surface 4 located at the most downstream side of the combustion gas flow path 2. In addition, a combustion gas flow rate sensor 10 for detecting the flow rate of the combustion gas flowing through the combustion gas flow path 2 is provided in the combustion gas flow path 2.

[0018] Steam temperature sensors 12 for detecting steam temperature are provided on the inlet and outlet sides of each heat transfer surface 4 in the steam flow path 6. In this embodiment, the steam temperature sensors 12 include a first steam temperature sensor 12a provided on the outlet side of the first heat transfer surface 4a, a second steam temperature sensor 12b provided between the inlet side of the first heat transfer surface 4a and the outlet side of the second heat transfer surface 4b, and a third steam temperature sensor 12c provided on the inlet side of the second heat transfer surface 4b. In addition, a steam flow rate sensor 14 for detecting the flow rate of steam flowing through the steam flow path 6 is provided in the steam flow path 6.

[0019] Steam pressure sensors 13 for detecting steam pressure are provided on the inlet and outlet sides of each heat transfer surface 4 in the steam flow path 6. In this embodiment, the steam pressure sensors 13 include a first steam pressure sensor 13a provided on the outlet side of the first heat transfer surface 4a, a second steam pressure sensor 13b provided between the inlet side of the first heat transfer surface 4a and the outlet side of the second heat transfer surface 4b, and a third steam pressure sensor 13c provided on the inlet side of the second heat transfer surface 4b.

[0020] In a boiler 1 having such a configuration, the temperature of the combustion gas flowing through the combustion gas flow path 2 cannot be measured except at the outlet side of the heat transfer surface 4 (4a) located furthest downstream, where it can be detected by the combustion gas temperature sensor 8. Therefore, in order to detect the combustion gas temperature on the inlet side of each heat transfer surface 4 provided in the combustion gas flow path 2, it is necessary to provide an additional combustion gas temperature sensor on the inlet side of each heat transfer surface 4. However, since the combustion gas is hot, this may not be desirable from the perspective of cost reduction. Therefore, in this embodiment, the combustion gas temperature estimation device 100 described below can be used to preferably estimate the combustion gas temperature Tgin on the inlet side of each heat transfer surface 4 without providing an additional combustion gas temperature sensor.

[0021] (Combustion gas temperature estimation device) FIG. 2 is a block diagram showing the configuration of a combustion gas temperature estimation device 100 according to one embodiment. The combustion gas temperature estimation device 100 includes, for example, a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and a computer-readable storage medium. A series of processes for implementing various functions is stored in a storage medium or the like in the form of a program, for example. The CPU reads the program into the RAM or the like and executes information processing and arithmetic operations to implement various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0022] As shown in FIG. 2, the combustion gas temperature estimation device 100 includes an inlet-side steam temperature acquisition unit 102, an inlet-side steam pressure acquisition unit 104, an outlet-side steam temperature acquisition unit 106, an outlet-side steam pressure acquisition unit 108, a steam flow rate acquisition unit 110, an outlet-side combustion gas temperature acquisition unit 112, a combustion gas flow rate acquisition unit 114, a steam endothermic heat calculation unit 116, an enthalpy change calculation unit 118, an outlet-side combustion gas enthalpy calculation unit 119, an inlet-side combustion gas enthalpy calculation unit 120, and an inlet-side combustion gas temperature calculation unit 122.

[0023] Here, each block of the combustion gas temperature estimation device 100 will be described with reference to Fig. 3. Fig. 3 is a schematic diagram illustrating the vicinity of the heat transfer surface 4 of Fig. 1. Fig. 3 schematically illustrates heat exchange between the combustion gas flowing through the combustion gas flow path 2 and the steam flowing through the steam flow path 6 on one of the heat transfer surfaces 4 of the boiler 1 (which may be the first heat transfer surface 4a or the second heat transfer surface 4b).

[0024] The inlet-side steam temperature acquisition unit 102 is configured to acquire the steam temperature (inlet-side steam temperature Tsin) on the inlet side of the heat transfer surface 4. As described above, steam temperature sensors 12 (first steam temperature sensor 12a, second steam temperature sensor 12b, third steam temperature sensor 12c) are installed on the inlet side of each heat transfer surface 4 in the steam flow path 6, and the inlet-side steam temperature acquisition unit 102 acquires the inlet-side steam temperature Tsin by receiving the detection values ​​of these steam temperature sensors 12.

[0025] The inlet-side steam pressure acquisition unit 104 is configured to acquire the steam pressure (inlet-side steam pressure Psin) on the inlet side of the heat transfer surface 4. As described above, steam pressure sensors 13 (first steam pressure sensor 13a, second steam pressure sensor 13b, third steam pressure sensor 13c) are installed on the inlet side of each heat transfer surface 4 in the steam flow path 6, and the inlet-side steam pressure acquisition unit 104 acquires the inlet-side steam pressure Psin by receiving the detection values ​​of these steam pressure sensors 13.

[0026] The outlet-side steam temperature acquisition unit 106 is configured to acquire the steam temperature (outlet-side steam temperature Tsout) on the outlet side of the heat transfer surface 4. As described above, steam temperature sensors 12 (first steam temperature sensor 12a, second steam temperature sensor 12b, third steam temperature sensor 12c) are installed on the outlet side of each heat transfer surface 4 in the steam flow path 6, and the outlet-side steam temperature acquisition unit 106 acquires the outlet-side steam temperature Tsout by receiving the detection values ​​of these steam temperature sensors 12.

[0027] The outlet-side steam pressure acquisition unit 108 is configured to acquire the steam pressure (outlet-side steam pressure Psout) on the outlet side of the heat transfer surface 4. As described above, steam pressure sensors 13 (first steam pressure sensor 13a, second steam pressure sensor 13b, third steam pressure sensor 13c) are installed on the outlet side of each heat transfer surface 4 in the steam flow path 6, and the outlet-side steam pressure acquisition unit 108 acquires the outlet-side steam pressure Psout by receiving the detection values ​​of these steam pressure sensors 13.

[0028] The steam flow rate obtaining unit 110 is configured to obtain the steam flow rate Fs in the steam flow path 6. As described above, the steam flow rate sensor 14 is installed in the steam flow path 6, and the steam flow rate obtaining unit 110 obtains the steam flow rate Fs by receiving the detection value of the steam flow rate sensor 14.

[0029] The outlet-side combustion gas temperature acquisition unit 112 is configured to acquire the combustion gas temperature (outlet-side combustion gas temperature Tgout) at the outlet side of the heat transfer surface 4. Specifically, when the inlet-side combustion gas temperature Tgin to be estimated is that of the first heat transfer surface 4a on the most downstream side, the outlet-side combustion gas temperature acquisition unit 112 acquires the outlet-side combustion gas temperature Tgout by receiving the detection value of the combustion gas temperature sensor 8 installed on the outlet side of the first heat transfer surface 4a. On the other hand, when the inlet-side combustion gas temperature Tgin to be estimated is that of another heat transfer surface (the second heat transfer surface 4b), the outlet-side combustion gas temperature acquisition unit 112 acquires the inlet-side combustion gas temperature Tgin (estimated value) estimated for the first heat transfer surface 4a located closest downstream as the outlet-side combustion gas temperature Tgout.

[0030] The combustion gas flow rate obtaining unit 114 is configured to obtain the combustion gas flow rate Fg in the combustion gas flow path 2. As described above, the combustion gas flow rate sensor 10 is installed in the combustion gas flow path 2, but even if a flow rate sensor is not installed, a gas flow rate estimated using an index analogous to the combustion gas flow rate sensor can be used instead, and the combustion gas flow rate obtaining unit 114 obtains the combustion gas flow rate Fg by receiving the detection value of the combustion gas flow rate sensor 10 or an estimated gas flow rate that can be analogized thereto.

[0031] The steam heat absorption calculation unit 116 is configured to calculate the steam heat absorption amount Qs at the heat transfer surface 4, and is configured with a steam enthalpy calculation unit 116a and a heat absorption amount calculation unit 116b. The steam enthalpy calculation unit 116a calculates the steam enthalpy change amount Es based on the inlet-side steam temperature Tsin acquired by the inlet-side steam temperature acquisition unit 102, the inlet-side steam pressure Psin acquired by the inlet-side steam pressure acquisition unit 104, the outlet-side steam temperature Tsout acquired by the outlet-side steam temperature acquisition unit 106, and the outlet-side steam pressure Psout acquired by the outlet-side steam pressure acquisition unit 108. The heat absorption amount calculation unit 116b calculates the heat absorption amount Qs of the steam from the heat transfer surface 4 based on the steam enthalpy change amount Es calculated by the steam enthalpy calculation unit 116a and the steam flow rate Fs acquired by the steam flow rate acquisition unit 110.

[0032] The enthalpy change calculation unit 118 is configured to calculate the enthalpy change ΔEg of the combustion gas on the heat transfer surface 4. Specifically, the enthalpy change calculation unit 118 calculates the enthalpy change ΔEg based on the flow rate Fg of the combustion gas acquired by the combustion gas flow rate acquisition unit 114 and the steam endothermic heat Qs calculated by the steam endothermic heat calculation unit 116.

[0033] The outlet-side combustion gas enthalpy calculation unit 119 is configured to calculate the enthalpy corresponding to the outlet-side combustion gas temperature (outlet-side combustion gas enthalpy). Specifically, the outlet-side combustion gas enthalpy calculation unit 119 calculates the outlet-side combustion gas enthalpy by converting the outlet-side combustion gas temperature Tgout acquired by the outlet-side combustion gas temperature acquisition unit 122.

[0034] The inlet-side combustion gas enthalpy calculation unit 120 is configured to calculate the enthalpy (inlet-side combustion gas enthalpy Egin) of the combustion gas on the inlet side of the heat transfer surface 4. Specifically, the inlet-side combustion gas enthalpy calculation unit 120 calculates the inlet-side combustion gas enthalpy Egin by adding the enthalpy change ΔEg calculated by the enthalpy change calculation unit 118 to the outlet-side combustion gas enthalpy Egout calculated by the outlet-side combustion gas enthalpy calculation unit 119.

[0035] The inlet-side combustion gas temperature calculation unit 122 is configured to calculate the inlet-side combustion gas temperature Tgin (estimated value) of the heat transfer surface 4. Specifically, the inlet-side combustion gas temperature calculation unit 122 calculates the inlet-side combustion gas temperature Tgin by converting the inlet-side combustion gas enthalpy Egin calculated by the inlet-side combustion gas enthalpy calculation unit 120 into temperature.

[0036] Next, a description will be given of a combustion gas temperature estimation method that can be implemented using the combustion gas temperature estimation device 100 having the above configuration. Fig. 4 is a flowchart showing a combustion gas temperature estimation method according to one embodiment.

[0037] First, the combustion gas temperature estimation device 100 determines whether the operating state of the boiler 1 is static (step S100). A static operating state means that the operating state is stable and is not in a transient state, for example.

[0038] If the operating state of the boiler 1 is static (step S100: YES), the combustion gas temperature estimation device 100 identifies the heat transfer surfaces 4 present in the combustion gas flow path 2 (step S101). In the example of Fig. 1, two heat transfer surfaces (a first heat transfer surface 4a and a second heat transfer surface 4b) present in the combustion gas flow path 2 are identified.

[0039] Next, the combustion gas temperature estimation device 100 estimates the inlet-side combustion gas temperature Tgin for the heat transfer surface located on the most downstream side among the multiple heat transfer surfaces 4 (in the example of FIG. 1, the first heat transfer surface 4a) (step S102). In step S102, the outlet-side combustion gas temperature acquisition unit 112 acquires as the outlet-side combustion gas temperature Tgout the detection value of the combustion gas temperature sensor 8 installed on the outlet side of the most downstream heat transfer surface (for example, the inlet side of the economizer), thereby estimating the inlet-side combustion gas temperature Tgin.

[0040] Next, it is determined whether or not there is another heat transfer surface 4 upstream of the heat transfer surface 4 for which the inlet-side combustion gas temperature Tgin was estimated in step S102 (step S103). In the example of FIG. 1, the second heat transfer surface 4 is upstream of the first heat transfer surface 4a for which the inlet-side combustion gas temperature Tgin was estimated in step S102. If there is another heat transfer surface like this (step S103: YES), the inlet-side combustion gas temperature Tgin is estimated for that other heat transfer surface 4 (step S104). In step S104, the inlet-side combustion gas temperature Tgin of the downstream heat transfer surface 4 estimated in step S102 is used as the outlet-side combustion gas temperature Tgout. In the example of Figure 1, in step S104, the outlet-side combustion gas temperature acquisition unit 112 acquires the inlet-side combustion gas temperature Tgin of the first heat transfer surface 4a estimated in step S102 as the outlet-side combustion gas temperature Tgout of the second heat transfer surface 4b, thereby estimating the inlet-side combustion gas temperature Tgin of the second heat transfer surface 4b.

[0041] When the estimation of the inlet-side combustion gas temperature Tgin is completed for the other heat transfer surfaces 4, the process returns to step S103. If there are no other heat transfer surfaces 4 (step S103: NO), it is determined that the estimation of the inlet-side combustion gas temperature Tgin is completed for all heat transfer surfaces 4, and the series of processes ends.

[0042] As described above, the combustion gas temperature estimation device 100 configured as described above can accurately estimate the inlet-side combustion gas temperature Tgin of each heat transfer surface 4 without installing an additional device such as a temperature sensor.

[0043] (heat transfer surface evaluation device) Next, a heat transfer surface evaluation device 200 using the above-mentioned combustion gas temperature estimation device 100 will be described. Fig. 5 is a block diagram showing the configuration of the heat transfer surface evaluation device 200 according to one embodiment. The heat transfer surface evaluation device 200 includes the above-mentioned combustion gas temperature estimation device 100 and an effective heat transfer area calculation unit 202.

[0044] The effective heat transfer area calculation unit 202 is configured to calculate the effective heat transfer area (SEF: Surface Efficiency Factor) of each heat transfer surface, and includes a representative gas vapor temperature difference calculation unit 204, a virtual heat transfer coefficient calculation unit 208, a reference heat transfer coefficient acquisition unit 210, and an effective heat transfer area calculation unit 212.

[0045] The representative gas / steam temperature difference calculation unit 204 is configured to calculate the temperature difference between the combustion gas and steam at each heat transfer surface 4. The representative gas / steam temperature difference calculation unit 204 may, for example, calculate the representative combustion gas temperature Tg as the average value of the inlet combustion gas temperature Tgin and the outlet combustion gas temperature Tgout, calculate the representative steam temperature Ts as the average value of the inlet steam temperature Tsin and the outlet steam temperature Tsout, and output the temperature difference between the representative combustion gas temperature Tg and the representative steam temperature Ts. Alternatively, the calculation may be performed using the logarithmic mean temperature difference between the inlet combustion gas temperature Tgin, the outlet combustion gas temperature Tgout, the inlet steam temperature Tsin, and the outlet steam temperature Tsout.

[0046] The virtual heat transfer coefficient calculation unit 208 is configured to calculate the virtual heat transfer coefficient R based on the representative gas vapor temperature difference ΔTgs calculated by the representative gas vapor temperature difference calculation unit 204. The virtual heat transfer coefficient calculation unit 208 calculates the virtual heat transfer coefficient R based on the representative gas vapor temperature difference ΔTgs calculated by the representative gas vapor temperature difference calculation unit 204, for example.

[0047] The reference heat transfer coefficient acquiring unit 210 is configured to acquire the reference heat transfer coefficient R'. The reference heat transfer coefficient R' is a heat transfer coefficient defined as a specification for each heat transfer surface 4, and is, for example, a design value. Such a reference heat transfer coefficient R' is stored in advance in a storage medium (not shown), and is acquired by being read out by the reference heat transfer coefficient acquiring unit 210.

[0048] The effective heat transfer area calculation unit 212 is configured to calculate the effective heat transfer area S of each heat transfer surface 4 based on the virtual heat transfer coefficient R calculated by the virtual heat transfer coefficient calculation unit 208 and the reference heat transfer coefficient R' calculated by the reference heat transfer coefficient acquisition unit 210. Specifically, the effective heat transfer area calculation unit 212 calculates the effective heat transfer area S as the ratio of the virtual heat transfer coefficient R to the reference heat transfer coefficient R'. The effective heat transfer area S calculated in this manner becomes smaller when dirt accumulates on the heat transfer surface 4 and the heat transfer characteristics deteriorate. Therefore, the effective heat transfer area S can be used as an index showing the influence of dirt accumulated on each heat transfer surface 4.

[0049] Fig. 6 is a modified example of Fig. 5. The heat transfer surface evaluation device 200 according to this modified example differs from that shown in Fig. 4 in that it further includes a correction unit 214 for correcting the effective heat transfer area S. The correction unit 214 calculates a correction value Sa to be multiplied by the effective heat transfer area S calculated by the effective heat transfer area calculation unit 212. The correction value Sa is set depending on the inlet-side combustion gas temperature Tgin calculated by the combustion gas temperature estimation device 100.

[0050] 7 is a characteristic graph showing the relationship between the correction value Sa calculated by the correction unit 214 in FIG. 6 and the inlet-side combustion gas temperature Tgin calculated by the combustion gas temperature estimation device 100. The correction value Sa is defined to increase as the inlet-side combustion gas temperature Tgin calculated by the combustion gas temperature estimation device 100 increases, and FIG. 7 particularly illustrates a case where the two are proportional to each other. Generally, the effective heat transfer area S has the characteristic that it increases as the inlet-side combustion gas temperature Tgin increases. Therefore, the effective heat transfer area can be calculated more accurately by multiplying the effective heat transfer area S calculated by the effective heat transfer area calculation unit 212 by such a correction value Sa to obtain a corrected effective heat transfer area S'.

[0051] (Control device) Next, a description will be given of a control device for controlling the boiler 1 based on the effective heat transfer area S calculated as an evaluation index for each heat transfer surface 4 by the heat transfer surface evaluation device 200 described above. In the following description, as one embodiment of the control device, a soot blower device for removing soot (such as dust) adhering to the heat transfer surface 4 by blowing an airflow onto the soot will be described as an example of a controlled object, but the controlled object of the control device is not limited to this and can be widely adopted.

[0052] 8 is a block diagram showing the configuration of a control device 300 according to one embodiment. The control device 300 includes an effective heat transfer area acquisition unit 302 for acquiring the effective heat transfer area S of each heat transfer surface 4 calculated by the heat transfer surface evaluation device 200, and a control unit 304 for controlling the soot blower that is the object of control.

[0053] The effective heat transfer area acquisition unit 302 acquires the effective heat transfer area S calculated for each heat transfer surface 4 by the heat transfer surface evaluation device 200. This allows the heat transfer state to be grasped for each of the multiple heat transfer surfaces 4. Then, the control unit 304 controls the soot blower provided on each heat transfer surface 4 based on the effective heat transfer area S acquired by the effective heat transfer area acquisition unit 302. The control unit 304 controls the soot blower so that, for example, the effective heat transfer area S of each heat transfer surface 4 becomes equal to or greater than a preset threshold value S0.

[0054] Figure 9 shows the results of a verification showing the transition of the effective heat transfer area S of a certain heat transfer surface 4. According to these results, the soot blower operates at times t1 and t2 when the effective heat transfer area S becomes less than the threshold value S0, thereby controlling the effective heat transfer area S to be equal to or greater than the specific threshold value set for each heat transfer surface. In this way, by operating the soot blower corresponding to each heat transfer surface 4 based on the effective heat transfer area S, the effective heat transfer area S of each heat transfer surface 4 is maintained within an appropriate range for each heat transfer surface. This makes it possible to maintain a good heat transfer state of the heat transfer surface 4 while suppressing energy consumption due to unnecessary operation of the soot blower.

[0055] Furthermore, the effective heat transfer area S of each heat transfer surface 4 calculated by the heat transfer surface evaluation device 200 can be used as appropriate for the operation and various maintenance of the boiler 1. For example, the fuel used to generate combustion gas in the furnace of the boiler 1 may contain an antifouling agent to prevent fouling from adhering to the heat transfer surface 4. In this case, the amount of antifouling agent added to the fuel may be adjusted based on the effective heat transfer area S.

[0056] Furthermore, as described above, the effective heat transfer area S is an index of the amount of dirt adhering to the heat transfer surface 4, so the amount of dirt adhering to each heat transfer surface 4 can be identified based on the effective heat transfer area S, and the timing of maintenance such as dirt removal work can be managed based on that amount of dirt. In particular, because the effective heat transfer area S is calculated for each heat transfer surface 4, the amount of dirt adhering to each heat transfer surface 4 can be identified individually. Therefore, for example, by identifying heat transfer surfaces 4 with a large amount of dirt adhering, it is possible to determine the areas that require focused dirt removal work during maintenance.

[0057] The effective heat transfer area S can also be an index showing the amount of metal thinning / corrosion on the heat transfer surface 4. From this perspective, the timing of maintenance such as repair work for metal thinning / corrosion that has occurred on each heat transfer surface 4 can be managed based on the effective heat transfer area S. In particular, because the effective heat transfer area S is calculated for each heat transfer surface 4, the amount of metal thinning / corrosion on each heat transfer surface 4 can be identified individually. Therefore, for example, by identifying heat transfer surfaces 4 with large amounts of metal thinning / corrosion, it is possible to grasp the areas that require focused repair work during maintenance.

[0058] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0059] The contents described in each of the above embodiments can be understood, for example, as follows.

[0060] (1) A combustion gas temperature estimation device according to one aspect includes: A combustion gas temperature estimation device (100) for estimating a temperature of combustion gas supplied to at least one heat transfer surface (4) for heat exchange with steam, comprising: an outlet-side combustion gas temperature acquisition unit (112) for acquiring an outlet-side combustion gas temperature (Tgout) of the heat transfer surface; a combustion gas flow rate acquisition unit (114) for acquiring the flow rate (Fg) of the combustion gas; a steam heat absorption calculation unit (116) for calculating a heat absorption amount (Qs) of the steam on the heat transfer surface; an enthalpy change calculation unit (118) for calculating an enthalpy change (ΔEg) of the combustion gas on the heat transfer surface based on the amount of heat absorbed and the flow rate of the combustion gas; an inlet-side combustion gas enthalpy calculation unit (120) for calculating an inlet-side combustion gas enthalpy (Egin) of the combustion gas at the inlet side of the heat transfer surface by adding the enthalpy change amount to an enthalpy (Egout) corresponding to the outlet-side combustion gas temperature; an inlet-side combustion gas temperature calculation unit (122) for calculating an inlet-side combustion gas temperature (Tgin) of the heat transfer surface based on the inlet-side combustion gas enthalpy; Equipped with.

[0061] According to the above aspect (1), the enthalpy change of the combustion gas due to the heat transfer surface is calculated based on the amount of heat absorbed by the steam that exchanges heat with the combustion gas, and the enthalpy of the inlet-side combustion gas is obtained by adding this to the enthalpy corresponding to the outlet-side combustion gas temperature. This allows the inlet-side combustion gas temperature to be accurately estimated based on the inlet-side combustion gas enthalpy without installing a device such as a temperature sensor on the inlet side of the heat transfer surface. Furthermore, by performing this estimation calculation of the inlet-side combustion gas temperature sufficiently quickly, real-time estimation of the inlet-side combustion gas temperature is possible.

[0062] (2) In another embodiment, in the above embodiment (1), the at least one heat transfer surface includes a first heat transfer surface (4a) and a second heat transfer surface (4b) provided upstream along the flow direction of the combustion gas; When the inlet-side combustion gas temperature calculation unit calculates the inlet-side combustion gas temperature for the second heat transfer surface, the outlet-side combustion gas temperature acquisition unit acquires the result of the inlet-side combustion gas temperature calculation unit's calculation of the inlet-side combustion gas temperature for the first heat transfer surface as the outlet-side combustion gas temperature of the second heat transfer surface.

[0063] According to the above aspect (2), the inlet-side combustion gas temperature can be estimated at each of the first and second heat transfer surfaces provided along the flow direction of the combustion gas. In particular, the inlet-side combustion gas temperature at the second heat transfer surface provided upstream can be estimated by using the estimated inlet-side combustion gas temperature at the first heat transfer surface provided downstream as the outlet combustion gas temperature at the second heat transfer surface. This makes it possible to computationally estimate the inlet-side combustion gas temperature at each heat transfer surface without installing devices such as temperature sensors on the inlet side of multiple heat transfer surfaces.

[0064] (3) In another aspect, in the above aspect (1) or (2), the at least one heat transfer surface includes a plurality of heat transfer surfaces (4a, 4b) provided along the flow direction of the combustion gas, When the inlet-side combustion gas temperature calculation unit calculates the inlet-side combustion gas temperature for the heat transfer surface located at the most downstream of the plurality of heat transfer surfaces, the outlet-side combustion gas temperature acquisition unit acquires a detection value of a temperature sensor (8) provided downstream of the plurality of heat transfer surfaces.

[0065] (4) In another aspect, in any one of the above (1) to (3), an inlet-side steam temperature detection unit (102) for detecting an inlet-side steam temperature (Tsin) of the heat transfer surface; an inlet-side steam pressure detection unit (104) for detecting an inlet-side steam pressure (Psin) of the heat transfer surface; an outlet-side steam temperature detection unit (106) for detecting an outlet-side steam temperature (Tsout) of the heat transfer surface; an outlet-side steam pressure detection unit (108) for detecting an outlet-side steam pressure (Psout) of the heat transfer surface; Further provided with The steam heat absorption calculation unit calculates the enthalpy of the steam based on the inlet side steam temperature, the inlet side steam pressure, the outlet side steam temperature, and the outlet side steam pressure, and calculates the heat absorption amount based on the enthalpy of the steam.

[0066] According to the above aspect (4), the amount of heat absorption by the steam required to calculate the inlet-side combustion gas temperature is calculated based on the temperature and pressure of the steam detected on the inlet side and outlet side of the heat transfer surface.

[0067] (5) A heat transfer surface evaluation device according to one aspect includes: The combustion gas temperature estimation device (100) described above in (4), an effective heat transfer area calculation unit (202) for calculating an effective heat transfer area (S) of the heat transfer surface based on the inlet-side combustion gas temperature, the outlet-side combustion gas temperature, the inlet-side steam temperature, the outlet-side steam temperature, and the amount of heat absorption; Equipped with.

[0068] According to the above aspect (5), the effective heat transfer area of ​​the heat transfer surface is calculated based on the temperatures of the combustion gas and steam at the inlet and outlet sides of the heat transfer surface and the amount of heat absorption. The effective heat transfer area thus obtained can be used, for example, as an index showing the effect of dirt accumulated on the heat transfer surface.

[0069] (6) In another embodiment, in the above embodiment (5), The system further includes a correction value calculation unit (214) for calculating a correction value (Sa) to be multiplied by the effective heat transfer area based on the inlet side combustion gas temperature.

[0070] According to the above aspect (6), the calculation result of the effective heat transfer area is corrected by multiplying the effective heat transfer area calculated by the effective heat transfer area calculation unit by the correction value, which makes it possible to take into account the influence of the effective heat transfer area changing depending on the inlet side combustion gas temperature, thereby enabling more accurate calculation of the effective heat transfer area.

[0071] (7) In another embodiment, in the above embodiment (6), The correction value is set to increase as the inlet side combustion gas temperature increases.

[0072] According to the above aspect (7), the effective heat transfer area can be calculated with higher accuracy by taking into consideration the characteristic that the higher the inlet side combustion gas temperature, the larger the effective heat transfer area.

[0073] (8) A control device (300) according to one aspect includes: A heat transfer surface evaluation device (200) according to any one of (5) to (7), a control unit (304) for controlling a soot blower for removing soot from the heat transfer surface based on the effective heat transfer area; Equipped with.

[0074] According to the above aspect (8), the soot blower is controlled based on the calculated effective heat transfer area for the heat transfer surface. Since the effective heat transfer area is an indicator of the fouling of the heat transfer surface, by controlling the soot blower based on the size of the effective heat transfer area, it is possible to remove soot at an appropriate time.

[0075] (9) A combustion gas temperature estimation method according to one aspect includes: A combustion gas temperature estimation method for estimating a temperature of combustion gas supplied to at least one heat transfer surface (4) for heat exchange with steam, comprising: Obtaining the combustion gas temperature (Tgout) at the outlet side of the heat transfer surface; Obtaining the flow rate (Fg) of the combustion gas; Calculating the amount of heat absorbed by the steam on the heat transfer surface (Qs); Calculating an enthalpy change (ΔEg) of the combustion gas on the heat transfer surface based on the amount of heat absorbed and the flow rate of the combustion gas; Calculating an inlet-side combustion gas enthalpy (Egin) of the combustion gas at the inlet side of the heat transfer surface by adding the enthalpy change amount to the enthalpy (Egout) corresponding to the outlet-side combustion gas temperature; Calculating an inlet-side combustion gas temperature (Tgin) of the heat transfer surface based on the inlet-side combustion gas enthalpy; Equipped with.

[0076] According to the above aspect (9), the enthalpy of the inlet-side combustion gas is obtained by calculating the enthalpy change of the combustion gas due to the heat transfer surface based on the amount of heat absorbed by the steam that exchanges heat with the combustion gas and adding this to the enthalpy corresponding to the outlet-side combustion gas temperature. This allows the inlet-side combustion gas temperature to be accurately estimated based on the inlet-side combustion gas enthalpy without installing a device such as a temperature sensor on the inlet side of the heat transfer surface. Furthermore, by performing this estimation calculation of the inlet-side combustion gas temperature sufficiently quickly, real-time estimation of the inlet-side combustion gas temperature is possible.

[0077] (10) A heat transfer surface evaluation method according to one aspect includes: the above( 9 ) The method includes a step of calculating an effective heat transfer area (S) of the heat transfer surface based on the inlet-side combustion gas temperature, the outlet-side combustion gas temperature, the inlet-side steam temperature of the heat transfer surface, the outlet-side steam temperature of the heat transfer surface, and the heat absorption amount, all of which are estimated by the combustion gas temperature estimation method of the above aspect.

[0078] According to the above aspect (10), the effective heat transfer area of ​​the heat transfer surface is calculated based on the temperatures of the combustion gas and steam at the inlet and outlet sides of the heat transfer surface and the amount of heat absorption. The effective heat transfer area thus obtained can be used, for example, as an index showing the effect of dirt accumulated on the heat transfer surface.

[0079] (11) A heat transfer surface management method according to one aspect includes: The method further includes a step of managing at least one of an antifouling agent to be added to a boiler for generating the combustion gas or a maintenance timing of the heat transfer surface based on the effective heat transfer area calculated by the heat transfer surface evaluation method of aspect (10) above.

[0080] According to the above aspect (11), at least one of the antifouling agent to be added to a boiler for generating combustion gas and the maintenance timing of the heat transfer surface is managed based on the effective heat transfer area, which is an index of the fouling of the heat transfer surface, etc. This makes it possible to prevent problems such as leakage by performing maintenance such as the application of the antifouling agent or regular inspections according to the progress of the fouling of the heat transfer surface, and monitoring the amount of thinning / corrosion of the heat transfer surface. [Explanation of symbols]

[0081] 1 boiler 2 Combustion gas flow path 4 Heat transfer surface 4a First heat transfer surface 4b Second heat transfer surface 4a First heat transfer surface 6 Steam flow path 8 Combustion gas temperature sensor 10 Combustion gas flow sensor 12 Steam temperature sensor 12a First steam temperature sensor 12b Second steam temperature sensor 12c Third steam temperature sensor 13 Steam pressure sensor 13a First steam pressure sensor 13b Second steam pressure sensor 13c Third steam pressure sensor 14 Steam flow sensor 100 Combustion gas temperature estimation device 102 Inlet steam temperature acquisition unit 104 Inlet steam pressure acquisition unit 106 Outlet steam temperature acquisition unit 108 Outlet steam pressure acquisition unit 110 Steam flow rate acquisition unit 112 Outlet side combustion gas temperature acquisition unit 114 Combustion gas flow rate acquisition unit 116 Steam endothermic heat calculation section 116a Steam enthalpy calculation section 116b Endothermic amount calculation part 118 Enthalpy change calculation section 119 Outlet combustion gas enthalpy calculation section 120 Inlet side combustion gas enthalpy calculation section 122 Inlet side combustion gas temperature calculation section 200 Heat Transfer Surface Evaluation Device 202 Effective heat transfer area calculation section 204 Representative gas vapor temperature difference calculation section 208 Virtual heat transfer coefficient calculation section 210 Reference heat transfer coefficient acquisition section 212 Effective heat transfer area calculation section 214 Correction Unit 300 control device 302 Effective heat transfer area acquisition section 304 Control Unit

Claims

1. A heat transfer surface evaluation device including a combustion gas temperature estimation device for estimating a temperature of combustion gas supplied to at least one heat transfer surface for performing heat exchange with steam, an outlet-side combustion gas temperature acquisition unit for acquiring an outlet-side combustion gas temperature of the heat transfer surface; a combustion gas flow rate acquisition unit for acquiring a flow rate of the combustion gas; a steam heat absorption amount calculation unit for calculating the amount of heat absorption of the steam on the heat transfer surface; an enthalpy change calculation unit for calculating an enthalpy change of the combustion gas on the heat transfer surface based on the amount of heat absorbed and the flow rate of the combustion gas; an inlet-side combustion gas enthalpy calculation unit for calculating an inlet-side combustion gas enthalpy of the combustion gas at the inlet side of the heat transfer surface by adding the enthalpy change amount to the enthalpy corresponding to the outlet-side combustion gas temperature; an inlet-side combustion gas temperature calculation unit for calculating an inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy; an effective heat transfer area calculation unit for calculating an effective heat transfer area of ​​the heat transfer surface based on the inlet-side combustion gas temperature; a correction value calculation unit for calculating a correction value to be multiplied by the effective heat transfer area based on the inlet-side combustion gas temperature; A heat transfer surface evaluation device comprising:

2. the at least one heat transfer surface includes a first heat transfer surface and a second heat transfer surface provided upstream along a flow direction of the combustion gas; 2. The heat transfer surface evaluation device according to claim 1, wherein, when the inlet-side combustion gas temperature calculation unit calculates the inlet-side combustion gas temperature for the second heat transfer surface, the outlet-side combustion gas temperature acquisition unit acquires, as the outlet-side combustion gas temperature for the second heat transfer surface, a result of the inlet-side combustion gas temperature calculation unit calculating the inlet-side combustion gas temperature for the first heat transfer surface.

3. the at least one heat transfer surface includes a plurality of heat transfer surfaces provided along a flow direction of the combustion gas, 3. The heat transfer surface evaluation device according to claim 1, wherein when the inlet-side combustion gas temperature calculation unit calculates the inlet-side combustion gas temperature for the heat transfer surface located at the most downstream side among the plurality of heat transfer surfaces, the outlet-side combustion gas temperature acquisition unit acquires a detection value of a temperature sensor provided downstream of the plurality of heat transfer surfaces.

4. an inlet-side steam temperature detection unit for detecting an inlet-side steam temperature of the heat transfer surface; an inlet-side steam pressure detection unit for detecting an inlet-side steam pressure of the heat transfer surface; an outlet-side steam temperature detection unit for detecting an outlet-side steam temperature of the heat transfer surface; an outlet-side steam pressure detection unit for detecting an outlet-side steam pressure of the heat transfer surface; Further provided with 4. The heat transfer surface evaluation device according to claim 1, wherein the steam heat absorption amount calculation unit calculates enthalpy of the steam based on the inlet-side steam temperature, the inlet-side steam pressure, the outlet-side steam temperature, and the outlet-side steam pressure, and calculates the heat absorption amount based on the enthalpy of the steam.

5. 3. The heat transfer surface evaluation device according to claim 1, wherein the effective heat transfer area calculation unit calculates the effective heat transfer area of ​​the heat transfer surface based on the outlet-side combustion gas temperature, the inlet-side steam temperature of the heat transfer surface, the outlet-side steam temperature of the heat transfer surface, and the heat absorption amount.

6. 3. The heat transfer surface evaluation device according to claim 1, wherein the correction value is set to increase as the inlet side combustion gas temperature increases.

7. The heat transfer surface evaluation device according to claim 5 or 6, a control unit for controlling a soot blower for removing soot from the heat transfer surface based on the effective heat transfer area; A control device comprising:

8. 1. A combustion gas temperature estimation method for estimating a temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam, comprising: acquiring a combustion gas temperature at an outlet side of the heat transfer surface; obtaining a flow rate of the combustion gas; calculating the amount of heat absorbed by the steam on the heat transfer surface; calculating an enthalpy change amount of the combustion gas on the heat transfer surface based on the amount of heat absorbed and the flow rate of the combustion gas; calculating an inlet-side combustion gas enthalpy of the combustion gas at the inlet side of the heat transfer surface by adding the enthalpy change amount to the enthalpy corresponding to the outlet-side combustion gas temperature; calculating an inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy; calculating an effective heat transfer area of ​​the heat transfer surface based on the inlet-side combustion gas temperature; calculating a correction value to be multiplied by the effective heat transfer area based on the inlet-side combustion gas temperature; A heat transfer surface evaluation method comprising:

9. 9. The heat transfer surface evaluation method according to claim 8, wherein in the step of calculating the effective heat transfer area, the effective heat transfer area of ​​the heat transfer surface is calculated based on the outlet-side combustion gas temperature, the inlet-side steam temperature of the heat transfer surface, the outlet-side steam temperature of the heat transfer surface, and the heat absorption amount.

10. 10. A heat transfer surface management method, further comprising a step of managing at least one of an antifouling agent to be added to a boiler for generating the combustion gas and a maintenance timing of the heat transfer surface, based on the effective heat transfer area calculated by the heat transfer surface evaluation method according to claim 9.

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