WO2023085087A1 - Combustion gas temperature estimation device, heat transfer surface evaluation device, control device, combustion gas temperature estimation method, heat transfer surface evaluation method, and heat transfer surface management method - Google Patents

Abstract

This combustion gas temperature estimation device estimates the temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam. This device calculates the inlet-side combustion gas enthalpy of combustion gas at the inlet side of the heat transfer surface by calculating the amount of change in the enthalpy of combustion gas on the heat transfer surface on the basis of the amount of heat absorption of steam on the heat transfer surface and the combustion gas flow rate and adding the enthalpy change amount to the enthalpy corresponding to the outlet-side combustion gas temperature. Based on the inlet-side combustion gas enthalpy calculated in this way, the inlet-side combustion gas temperature of the heat transfer surface is calculated.

Description

Combustion gas temperature estimation device, heat transfer surface evaluation device, control device, combustion gas temperature estimation method, heat transfer surface evaluation method, and heat transfer surface management method

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.
This application claims priority based on Japanese Patent Application No. 2021-184876 filed with the Japan Patent Office on November 12, 2021, the contents of which are incorporated herein.

A boiler is known that can generate steam by exchanging heat with combustion gas generated by burning fuel such as coal through a heat transfer surface. Combustion gases generated in the boiler furnace are directed from the furnace exit toward the downstream economizer through the combustion gas flow path. The combustion gas flow path is provided with a plurality of heat transfer surfaces along the flow direction of the combustion gas, and heat is exchanged on these heat transfer surfaces to generate steam.

By the way, in order to evaluate the heat transfer state of the boiler, there are cases where the temperature of the combustion gas on the inlet side of each heat transfer surface provided in the combustion gas flow path is measured. Since it may be difficult to measure the combustion gas temperature on the inlet side of each heat transfer surface with a general temperature sensor if the temperature of the combustion gas is high, for example, in Patent Document 1, the downstream side economizer Estimating the inlet combustion gas temperature at each upstream heat transfer surface based on the inlet combustion gas temperature is disclosed.

JP-A-5-280703

In Patent Document 1, the combustion gas temperature on the inlet side of each heat transfer surface on the upstream side is estimated based on the combustion gas temperature on the inlet side of the economizer on the downstream side, but the pressure of the combustion gas and steam is taken into consideration. Estimate calculations are based on specific heat and temperature without Since the combustion gas temperature on the inlet side of each heat transfer surface depends on the pressure of the combustion gas and steam, it is difficult to accurately estimate it with a simple method such as that disclosed in Patent Document 1.

At least one embodiment of the present disclosure has been made in view of the above circumstances, and includes a combustion gas temperature estimation device, a heat transfer surface evaluation device, a control device, and a combustion gas temperature estimation device that can accurately estimate the combustion gas temperature on the inlet side of the heat transfer surface. An object of the present invention is to provide a gas temperature estimation method, a heat transfer surface evaluation method, and a heat transfer surface management method.

In order to solve the above problems, a 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,
A combustion gas temperature estimator for estimating the temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam, comprising:
an exit-side combustion gas temperature acquisition unit for acquiring an exit-side combustion gas temperature of the heat transfer surface;
a combustion gas flow rate acquisition unit for acquiring the flow rate of the combustion gas;
a steam heat absorption amount calculation unit for calculating the heat absorption amount of the steam on the heat transfer surface;
an enthalpy change amount calculation unit for calculating an enthalpy change amount of the combustion gas on the heat transfer surface based on the heat absorption amount and the flow rate of the combustion gas;
An inlet-side combustion gas enthalpy calculation unit for calculating the inlet-side combustion gas enthalpy of the combustion gas on 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. and,
an inlet-side combustion gas temperature calculator for calculating the inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy;
Prepare.

In order to solve the above problems, the heat transfer surface evaluation device according to at least one embodiment of the present disclosure,
a combustion gas temperature estimation device according to at least one embodiment of the present disclosure;
An effective heat transfer area 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 heat absorption amount. a thermal area calculator;
Prepare.

In order to solve the above problems, the control device according to at least one embodiment of the present disclosure,
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;
Prepare.

In order to solve the above problems, a combustion gas temperature estimation method according to at least one embodiment of the present disclosure includes:
A combustion gas temperature estimation method for estimating the temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam, comprising:
obtaining a combustion gas temperature on the 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 the inlet side combustion gas enthalpy of the combustion gas on 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 the inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy;
Prepare.

In order to solve the above problems, the 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, the inlet-side steam temperature of the heat transfer surface, and the outlet-side steam of the heat transfer surface estimated by the combustion gas temperature estimation method according to at least one embodiment of the present disclosure A step of calculating an effective heat transfer area of the heat transfer surface based on the temperature and the heat absorption amount.

According to at least one embodiment of the present disclosure, a combustion gas temperature estimation device capable of estimating the combustion gas temperature on the inlet side of the heat transfer surface with high accuracy, a heat transfer surface evaluation device, a control device, a combustion gas temperature estimation method, and a heat transfer surface An evaluation method and a heat transfer surface management method can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows simply the structure of the boiler which concerns on one Embodiment. 1 is a block diagram showing the configuration of a combustion gas temperature estimating device according to one embodiment; FIG. FIG. 2 is a schematic diagram extracting and showing the vicinity of the heat transfer surface in FIG. 1 ; 4 is a flow chart showing a combustion gas temperature estimation method according to one embodiment. 1 is a block diagram showing the configuration of a heat transfer surface evaluation device according to one embodiment; FIG. It is a modification of FIG. FIG. 7 is a characteristic graph showing the relationship between the correction value calculated by the correction unit of FIG. 6 and the inlet-side combustion gas temperature calculated by the combustion gas temperature estimating device; It is a block diagram which shows the structure of the control apparatus which concerns on one Embodiment. It is the verification result which shows transition of the effective heat-transfer area in a certain heat-transfer surface.

Several embodiments will be described below with reference to the accompanying drawings. However, the configurations described as the embodiments or illustrated in the drawings are not meant to limit the scope of the invention, but merely illustrative examples.

(Boiler configuration)
First, the configuration of a boiler that handles combustion gas, which is an 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 schematically showing the configuration of a boiler 1 according to one embodiment.

The boiler 1 has a combustion gas flow path 2 through which combustion gases produced in an upstream furnace (not shown) are made. At least one heat transfer surface 4 is provided in the combustion gas flow path 2 along the flow direction of the combustion gas. A plurality of heat transfer surfaces 4 may be provided in the combustion gas flow path 2, and in the example of FIG. surface 4b. These heat transfer surfaces 4 allow heat exchange between the combustion gas flowing through the combustion gas channel 2 and the steam flowing through the steam channel 6 .
Note that, for example, an economizer is arranged on the downstream side of the combustion gas flow path 2 .

A combustion gas temperature sensor 8 for detecting the temperature of the combustion gas is provided on the downstream side of the heat transfer surface 4 arranged on the most downstream side of the combustion gas flow path 2 . 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 also provided in the combustion gas flow path 2 .

A steam temperature sensor 12 for detecting the steam temperature is provided on the inlet side and the outlet side of each heat transfer surface 4 in the steam flow path 6 . In this embodiment, as the steam temperature sensor 12, a first steam temperature sensor 12a provided on the outlet side of the first heat transfer surface 4a, the inlet side of the first heat transfer surface 4a and the outlet side of the second heat transfer surface 4b A second steam temperature sensor 12b provided between and a third steam temperature sensor 12c provided on the inlet side of the second heat transfer surface 4b are shown. 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 .

A steam pressure sensor 13 for detecting the steam pressure is provided on the inlet side and the outlet side of each heat transfer surface 4 in the steam flow path 6 . In this embodiment, as the steam pressure sensor 13, a first steam pressure sensor 13a provided on the outlet side of the first heat transfer surface 4a, 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.

In the boiler 1 having such a configuration, the temperature of the combustion gas flowing through the combustion gas flow path 2 is actually measured except for the outlet side of the heat transfer surface 4 (4a) on the most downstream side that can be detected by the combustion gas temperature sensor 8. Can not. 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 additionally provide a combustion gas temperature sensor on the inlet side of each heat transfer surface 4. , the combustion gas is hot, which may not be preferable from the viewpoint of cost reduction. Therefore, in the present embodiment, the inlet-side combustion gas temperature Tgin of each heat transfer surface 4 can be preferably estimated by the combustion gas temperature estimating device 100 described below without additionally providing a combustion gas temperature sensor.

(Combustion gas temperature estimation device)
FIG. 2 is a block diagram showing the configuration of the combustion gas temperature estimation device 100 according to one embodiment. The combustion gas temperature estimating device 100 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, for example, and the CPU reads out this program to a RAM or the like, and executes information processing and arithmetic processing. As a result, various functions are realized. The program is 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. etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

As shown in FIG. 2, the combustion gas temperature estimating device 100 includes an inlet side steam temperature acquisition section 102, an inlet side steam pressure acquisition section 104, an outlet side steam temperature acquisition section 106, and an outlet side steam pressure acquisition section . , a steam flow rate acquisition unit 110, an outlet side combustion gas temperature acquisition section 112, a combustion gas flow rate acquisition section 114, a steam heat absorption amount calculation section 116, an enthalpy change amount calculation section 118, and an outlet side combustion gas enthalpy calculation section 119. , an inlet-side combustion gas enthalpy calculator 120 and an inlet-side combustion gas temperature calculator 122 .

Here, each block of the combustion gas temperature estimation device 100 will be described with reference to FIG. FIG. 3 is a schematic diagram showing the vicinity of the heat transfer surface 4 of FIG. 1 by extracting it. In FIG. 3, on any one of the heat transfer surfaces 4 of the boiler 1 (may be the first heat transfer surface 4a or the second heat transfer surface 4b), the combustion gas flow path 2 The heat exchange between the combustion gas flowing through and the steam flowing through the steam passage 6 is schematically shown.

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, the 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. The inlet-side steam temperature acquiring unit 102 acquires the inlet-side steam temperature Tsin by receiving the detected values of these steam temperature sensors 12 .

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, the 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. The inlet-side steam pressure acquisition unit 104 acquires the inlet-side steam pressure Psin by receiving the detected values of these steam pressure sensors 13 .

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, the 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. The outlet side steam temperature acquiring unit 106 acquires the outlet side steam temperature Tsout by receiving the detected values of these steam temperature sensors 12 .

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, the 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. The outlet side steam pressure acquisition unit 108 acquires the outlet side steam pressure Psout by receiving the detected values of these steam pressure sensors 13 .

The steam flow rate acquisition unit 110 is configured to acquire the steam flow rate Fs in the steam flow path 6 . As described above, the steam flow sensor 14 is installed in the steam flow path 6 , and the steam flow rate acquisition unit 110 acquires the steam flow rate Fs by receiving the detected value of the steam flow rate sensor 14 .

The exit-side combustion gas temperature acquisition unit 112 is configured to acquire the combustion gas temperature (exit-side combustion gas temperature Tgout) on the exit 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 obtains the temperature at the outlet of the first heat transfer surface 4a. By receiving the detected value of the combustion gas temperature sensor 8 installed on the side, the exit side combustion gas temperature Tgout is obtained. 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 obtains the first The inlet-side combustion gas temperature Tgin (estimated value) estimated for the heat transfer surface 4a is obtained as the outlet-side combustion gas temperature Tgout.

The combustion gas flow rate acquisition unit 114 is configured to acquire the combustion gas flow rate Fg in the combustion gas flow path 2 . As described above, the combustion gas flow sensor 10 is installed in the combustion gas flow path 2, and even if the flow sensor is not installed, the gas flow rate estimated by an analogous index can be substituted. The combustion gas flow rate acquisition unit 114 acquires the combustion gas flow rate Fg by receiving the detected value of the estimated gas flow rate that can be inferred from the combustion gas flow rate sensor 10 .

The steam heat absorption calculation unit 116 is a configuration for calculating the steam heat absorption amount Qs on the heat transfer surface 4, and includes a steam enthalpy calculation unit 116a and a heat absorption calculation unit 116b. The steam enthalpy calculation unit 116a obtains the inlet-side steam temperature Tsin obtained by the inlet-side steam temperature obtaining unit 102, the inlet-side steam pressure Psin obtained by the inlet-side steam pressure obtaining unit 104, and the outlet-side steam temperature obtaining unit 106. The steam enthalpy change amount Es is calculated based on the obtained outlet side steam temperature Tsout and the outlet side steam pressure Psout obtained by the outlet side steam pressure obtaining unit 108 . The heat absorption amount calculation unit 116b calculates the heat absorption amount 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. Calculate Qs.

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

The outlet-side combustion gas enthalpy calculator 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 .

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

The inlet-side combustion gas temperature calculator 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. .

Next, a combustion gas temperature estimation method that can be implemented using the combustion gas temperature estimation device 100 having the above configuration will be described. FIG. 4 is a flow chart showing a combustion gas temperature estimation method according to one embodiment.

First, the combustion gas temperature estimation device 100 determines whether or not the boiler 1 is in a static operating state (step S100). A static operating state means that the operating state is stable, eg, not in a transient state.

When the operating state of the boiler 1 is static (step S100: YES), the combustion gas temperature estimation device 100 identifies the heat transfer surface 4 existing in the combustion gas flow path 2 (step S101). In the example of FIG. 1, two heat transfer surfaces (the first heat transfer surface 4a and the second heat transfer surface 4b) in the combustion gas flow path 2 are specified.

Subsequently, the combustion gas temperature estimating device 100 estimates the inlet-side combustion gas temperature Tgin for the most downstream heat transfer surface (the first heat transfer surface 4a in the example of FIG. 1) among the plurality of heat transfer surfaces 4. (step S102). In step S102, in the outlet-side combustion gas temperature acquisition unit 112, the detection value of the combustion gas temperature sensor 8 installed on the outlet side of the heat transfer surface on the most downstream side (for example, the inlet side of the economizer) is the outlet-side combustion gas temperature. By obtaining the temperature Tgout, the inlet-side combustion gas temperature Tgin is estimated.

Subsequently, it is determined whether or not there is another heat transfer surface 4 upstream of the heat transfer surface 4 whose 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 (step S103: YES), the inlet side combustion gas temperature Tgin is estimated for the 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 FIG. 1, in step S104, the outlet-side combustion gas temperature acquisition unit 112 obtains the inlet-side combustion gas temperature Tgin of the first heat transfer surface 4a estimated in step S102 as the outlet-side temperature of the second heat transfer surface 4b. By obtaining the combustion gas temperature Tgout, the combustion gas temperature Tgin on the inlet side of the second heat transfer surface 4b is estimated.

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

As described above, according to the combustion gas temperature estimating apparatus 100 configured as described above, the inlet side combustion gas temperature Tgin of each heat transfer surface 4 can be accurately estimated without additionally installing a device such as a temperature sensor. .

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

The effective heat transfer area calculation unit 202 is a configuration for calculating the effective heat transfer area (SEF: Surface Efficiency Factor) of each heat transfer surface. 208 , a reference heat transfer coefficient acquisition unit 210 , and an effective heat transfer area calculation unit 212 .

The representative gas/steam temperature difference calculator 204 is configured to calculate the temperature difference between the combustion gas and the steam on each heat transfer surface 4 . The representative gas steam temperature difference calculation unit 204 calculates, for example, the representative combustion gas temperature Tg as an average value of the inlet side combustion gas temperature Tgin and the outlet side combustion gas temperature Tgout, and calculates the inlet side steam temperature Tsin and the outlet side steam temperature Tsout. A representative steam temperature Ts may be calculated as an average value of , and the temperature difference between the representative combustion gas temperature Tg and the representative steam temperature Ts may be output. Alternatively, it may be calculated using the logarithmic average 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.

The virtual heat transfer coefficient calculator 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 calculator 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.

The standard heat transfer coefficient acquisition unit 210 is configured to acquire the standard heat transfer coefficient R'. The reference heat transfer coefficient R' is a heat transfer coefficient specified 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 obtained by being read by the reference heat transfer coefficient obtaining unit 210 .

The effective heat transfer area calculation unit 212 calculates each This configuration is for calculating the effective heat transfer area S of the heat transfer surface 4 . Specifically, the effective heat transfer area calculator 212 calculates the effective heat transfer area S as a ratio between the virtual heat transfer coefficient R and 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 surfaces 4 and the heat transfer characteristics deteriorate. It is possible.

Fig. 6 is a modification of Fig. 5. A heat transfer surface evaluation apparatus 200 according to this modification 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 for multiplying 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 estimating device 100 .

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. FIG. The correction value Sa is defined to increase as the inlet-side combustion gas temperature Tgin calculated by the combustion gas temperature estimating device 100 increases, and FIG. In general, the effective heat transfer area S increases as the inlet side combustion gas temperature Tgin increases. By obtaining the corrected effective heat transfer area S′ by multiplying S, the effective heat transfer area can be calculated more accurately.

(Control device)
Next, a control device for controlling the boiler 1 based on the effective heat transfer area S calculated as the evaluation index of each heat transfer surface 4 by the heat transfer surface evaluation device 200 described above will be described. In the following description, as one embodiment of the control device, the control target is a soot blower device for removing soot by blowing an air flow against soot (such as soot) attached to the heat transfer surface 4. Although exemplified, the controlled object of the control device is not limited to this and can be widely adopted.

FIG. 8 is a block diagram showing the configuration of the 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 an effective heat transfer area acquisition unit 302 for controlling the soot blower to be controlled. and a control unit 304 .

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 . Thereby, the heat transfer state of each of the plurality of heat transfer surfaces 4 is grasped. Based on the effective heat transfer area S obtained by the effective heat transfer area obtaining unit 302 , the control unit 304 controls the soot blowers provided on each heat transfer surface 4 . The control of the soot blower by the control unit 304 is performed, for example, so that the effective heat transfer area S of each heat transfer surface 4 is equal to or greater than a preset threshold value S0.

　Fig. 9 shows the verification results showing the transition of the effective heat transfer area S on a certain heat transfer surface 4. According to this verification result, the soot blower operates at times t1 and t2 when the effective heat transfer area S is less than the threshold value S0, so that the effective heat transfer area S becomes equal to or greater than the unique threshold set for each heat transfer surface. controlled as By operating the soot blower corresponding to each heat transfer surface 4 based on the effective heat transfer area S in this manner, the effective heat transfer area S of each heat transfer surface 4 is set to an appropriate range for each heat transfer surface. is held to As a result, the heat transfer state of the heat transfer surface 4 can be favorably maintained while suppressing energy consumption due to unnecessary operation of the soot blower.

Also, the effective heat transfer area S of each heat transfer surface 4 calculated by the heat transfer surface evaluation device 200 can be appropriately used for the operation of the boiler 1 and various maintenances. For example, the fuel for generating the combustion gases in the furnace of the boiler 1 may contain antifouling agents to prevent fouling from adhering to the heat transfer surfaces 4 . In this case, the addition amount of the antifouling agent contained in the fuel may be adjusted based on the effective heat transfer area S.

Further, since the effective heat transfer area S is an index indicating the amount of dirt adhering to the heat transfer surface 4 as described above, the amount of dirt adhering to each heat transfer surface 4 is specified based on the effective heat transfer area S, and the Based on the adhesion amount, maintenance timing such as dirt removal work can be managed. In particular, since the effective heat transfer area S is calculated for each heat transfer surface 4, the amount of contaminants on each heat transfer surface 4 can be specified individually. Therefore, for example, by specifying the heat transfer surface 4 with a large amount of adhered dirt, it is possible to grasp the range in which the work of removing the dirt is required intensively during maintenance.

The effective heat transfer area S can also serve as an indicator of the amount of thinning/corrosion on the heat transfer surface 4 . From this point of view, the effective heat transfer area S may be used to manage the timing of maintenance such as repair work for thinning/corrosion occurring in each heat transfer surface 4 . In particular, since the effective heat transfer area S is calculated for each heat transfer surface 4, the thickness reduction/corrosion amount of each heat transfer surface 4 can be specified individually. Therefore, for example, by specifying the heat transfer surface 4 with a large amount of thinning/corrosion, it is also possible to grasp the range in which repair work is required intensively during maintenance.

In addition, it is possible to appropriately replace the components in the above-described embodiments with well-known components within the scope of the present disclosure, and the above-described embodiments may be combined as appropriate.

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

(1) A combustion gas temperature estimation device according to one aspect,
A combustion gas temperature estimating device (100) for estimating the 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 acquiring section (112) for acquiring the 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 vapor heat absorption calculation unit (116) for calculating the heat absorption amount (Qs) of the vapor 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 for calculating the inlet side combustion gas enthalpy (Egin) of the combustion gas on 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 a side combustion gas enthalpy calculator (120);
an inlet-side combustion gas temperature calculator (122) for calculating the inlet-side combustion gas temperature (Tgin) of the heat transfer surface based on the inlet-side combustion gas enthalpy;
Prepare.

According to the above aspect (1), the amount of 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 is added to the enthalpy corresponding to the outlet-side combustion gas temperature. By doing so, the enthalpy of the combustion gas on the inlet side is obtained. As a result, the inlet side combustion gas temperature can 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. In addition, by performing the calculation for estimating the inlet-side combustion gas temperature sufficiently quickly, the inlet-side combustion gas temperature can be estimated in real time.

(2) In another aspect, in the aspect of (1) above,
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 calculator calculates the inlet-side combustion gas temperature for the second heat transfer surface, the outlet-side combustion gas temperature acquisition unit calculates the outlet-side combustion gas temperature for the second heat transfer surface. As the temperature, the inlet-side combustion gas temperature calculation unit acquires the result of calculating the inlet-side combustion gas temperature for the first heat transfer surface.

According to the aspect (2) above, it is possible to estimate the inlet-side combustion gas temperature on the first heat transfer surface and the second heat transfer surface provided along the flow direction of the combustion gas. In particular, the inlet-side combustion gas temperature on the second heat transfer surface provided on the upstream side is calculated by using the estimation result of the inlet-side combustion gas temperature on the first heat transfer surface provided on the downstream side as the exit combustion gas temperature on the second heat transfer surface. By using it as the gas temperature, it is possible to estimate the inlet-side combustion gas temperature at each heat transfer surface. As a result, the combustion gas temperature on the inlet side of each heat transfer surface can be estimated computationally without installing a device such as a temperature sensor on the inlet side of the plurality of heat transfer surfaces.

(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 calculating unit calculates the inlet-side combustion gas temperature for the heat transfer surface positioned most downstream among the plurality of heat transfer surfaces, the outlet-side combustion gas temperature obtaining unit calculates the A detection value of a temperature sensor (8) provided downstream from the plurality of heat transfer surfaces is obtained.

(4) In another aspect, in any one aspect of (1) to (3) above,
an inlet-side steam temperature detector (102) for detecting the inlet-side steam temperature (Tsin) of the heat transfer surface;
an inlet-side steam pressure detector (104) for detecting the inlet-side steam pressure (Psin) of the heat transfer surface;
an outlet side steam temperature detector (106) for detecting the outlet side steam temperature (Tsout) of the heat transfer surface;
an outlet steam pressure detector (108) for detecting the outlet steam pressure (Psout) of the heat transfer surface;
further comprising
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 enthalpy of the steam based on the enthalpy of the steam. to calculate the amount of heat absorption.

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

(5) A heat transfer surface evaluation device according to one aspect,
The combustion gas temperature estimating device (100) of (4) above;
To calculate the 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 An effective heat transfer area calculation unit (202) of
Prepare.

According to the aspect (5) above, the effective heat transfer area of the heat transfer surface is calculated based on the temperature of the combustion gas and steam on the inlet side and the outlet side of the heat transfer surface and the heat absorption amount. The effective heat transfer area obtained in this manner can be used as an index indicating the influence of dirt accumulated on the heat transfer surface, for example.

(6) In another aspect, in the aspect of (5) above,
A correction value calculator (214) is further provided for calculating a correction value (Sa) to be multiplied by the effective heat transfer area based on the inlet side combustion gas temperature.

According to the aspect (6) above, the effective heat transfer area calculated by the effective heat transfer area calculator is multiplied by the correction value, thereby correcting the calculation result of the effective heat transfer area. As a result, it is possible to take into account the effect of the change in the effective heat transfer area depending on the temperature of the combustion gas on the inlet side, and to calculate the effective heat transfer area with higher accuracy.

(7) In another aspect, in the aspect of (6) above,
The correction value is set to increase as the inlet-side combustion gas temperature increases.

According to the above aspect (7), the effective heat transfer area can be calculated more accurately by taking into account the characteristic that the effective heat transfer area increases as the inlet side combustion gas temperature increases.

(8) A control device (300) according to one aspect,
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;
Prepare.

According to the aspect (8) above, the soot blower is controlled based on the effective heat transfer area calculated for the heat transfer surface. Since the effective heat transfer area is an index indicating the contamination of the heat transfer surface, soot can be removed at appropriate timing by controlling the soot blower based on the size of the effective heat transfer area.

(9) A combustion gas temperature estimation method according to one aspect includes:
A combustion gas temperature estimation method for estimating the temperature of combustion gas supplied to at least one heat transfer surface (4) for heat exchange with steam, comprising:
obtaining a combustion gas temperature (Tgout) on the outlet side of the heat transfer surface;
obtaining a flow rate (Fg) of the combustion gas;
calculating a heat absorption amount (Qs) of the steam on the heat transfer surface;
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 the inlet-side combustion gas enthalpy (Egin) of the combustion gas on 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;
Prepare.

According to the above aspect (9), the amount of enthalpy change of the combustion gas due to the heat transfer surface is calculated based on the amount of heat absorbed by the steam heat-exchanging with the combustion gas, and is added to the enthalpy corresponding to the outlet-side combustion gas temperature. By doing so, the enthalpy of the combustion gas on the inlet side is obtained. As a result, the inlet side combustion gas temperature can 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. In addition, by performing the calculation for estimating the inlet-side combustion gas temperature sufficiently quickly, the inlet-side combustion gas temperature can be estimated in real time.

(10) A heat transfer surface evaluation method according to one aspect includes:
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, estimated by the combustion gas temperature estimation method of the aspect (9) above, and calculating an effective heat transfer area (S) of the heat transfer surface based on the heat absorption amount.

According to the aspect (10) above, the effective heat transfer area of the heat transfer surface is calculated based on the temperature of the combustion gas and steam on the inlet side and the outlet side of the heat transfer surface and the amount of heat absorbed. The effective heat transfer area obtained in this manner can be used as an index indicating the influence of dirt accumulated on the heat transfer surface, for example.

(11) A heat transfer surface management method according to one aspect includes:
Based on the effective heat transfer area calculated by the heat transfer surface evaluation method of the aspect (10), an antifouling agent added to the boiler for generating the combustion gas, or maintenance of the heat transfer surface It further comprises a step of managing at least one of the timings.

According to the aspect (11) above, based on the effective heat transfer area, which is an index indicating the contamination of the heat transfer surface, the antifouling agent added to the boiler for generating the combustion gas, or the heat transfer surface at least one of the maintenance timing of As a result, maintenance such as antifouling agents and periodic inspections, and monitoring of thinning/corrosion amounts of the heat transfer surface can be carried out according to the progress of the heat transfer surface contamination, thereby preventing troubles such as leakage.

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 rate 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 rate sensor 100 Combustion gas temperature estimation device 102 Inlet side Steam temperature acquisition unit 104 Inlet side steam pressure acquisition unit 106 Outlet side steam temperature acquisition unit 108 Outlet side steam pressure acquisition unit 110 Steam flow rate acquisition unit 112 Exit side combustion gas temperature acquisition unit 114 Combustion gas flow rate acquisition unit 116 Steam heat absorption calculation unit 116a steam enthalpy calculator 116b heat absorption calculator 118 enthalpy change calculator 119 outlet side combustion gas enthalpy calculator 120 inlet side combustion gas enthalpy calculator 122 inlet side combustion gas temperature calculator 200 heat transfer surface evaluation device 202 effective heat transfer Area calculation unit 204 Representative gas vapor temperature difference calculation unit 208 Virtual heat transfer coefficient calculation unit 210 Reference heat transfer coefficient acquisition unit 212 Effective heat transfer area calculation unit 214 Correction unit 300 Control device 302 Effective heat transfer area acquisition unit 304 Control unit

Claims (11)

1. A combustion gas temperature estimator for estimating the temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam, comprising:
   an exit-side combustion gas temperature acquisition unit for acquiring an exit-side combustion gas temperature of the heat transfer surface;
   a combustion gas flow rate acquisition unit for acquiring the flow rate of the combustion gas;
   a steam heat absorption amount calculation unit for calculating the heat absorption amount of the steam on the heat transfer surface;
   an enthalpy change amount calculation unit for calculating an enthalpy change amount of the combustion gas on the heat transfer surface based on the heat absorption amount and the flow rate of the combustion gas;
   An inlet-side combustion gas enthalpy calculation unit for calculating the inlet-side combustion gas enthalpy of the combustion gas on 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. and,
   an inlet-side combustion gas temperature calculator for calculating the inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy;
   A combustion gas temperature estimator.
2. The at least one heat transfer surface includes a first heat transfer surface and a second heat transfer surface provided upstream along the flow direction of the combustion gas,
   When the inlet-side combustion gas temperature calculator calculates the inlet-side combustion gas temperature for the second heat transfer surface, the outlet-side combustion gas temperature acquisition unit calculates the outlet-side combustion gas temperature for the second heat transfer surface. 2. The combustion gas temperature estimating device according to claim 1, wherein said inlet-side combustion gas temperature calculator acquires, as the temperature, a result of calculating said inlet-side combustion gas temperature for said first heat transfer surface.
3. The at least one heat transfer surface includes a plurality of heat transfer surfaces provided along the flow direction of the combustion gas,
   When the inlet-side combustion gas temperature calculating unit calculates the inlet-side combustion gas temperature for the heat transfer surface positioned most downstream among the plurality of heat transfer surfaces, the outlet-side combustion gas temperature obtaining unit calculates the 3. A combustion gas temperature estimating device according to claim 1 or 2, which acquires a detected value of a temperature sensor provided downstream of the plurality of heat transfer surfaces.
4. an inlet-side steam temperature detection unit for detecting the inlet-side steam temperature of the heat transfer surface;
   an inlet-side steam pressure detection unit for detecting inlet-side steam pressure of the heat transfer surface;
   an outlet-side steam temperature detection unit for detecting the outlet-side steam temperature of the heat transfer surface;
   an outlet-side steam pressure detection unit for detecting the outlet-side steam pressure of the heat transfer surface;
   further comprising
   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 enthalpy of the steam based on the enthalpy of the steam. 3. The combustion gas temperature estimating device according to claim 1, wherein the amount of heat absorbed is calculated by
5. A combustion gas temperature estimating device according to claim 4;
   An effective heat transfer area 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 heat absorption amount. a thermal area calculator;
   A heat transfer surface evaluation device comprising:
6. The heat transfer surface evaluation device according to claim 5, further comprising 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.
7. The heat transfer surface evaluation device according to claim 6, wherein the correction value is set to increase as the inlet-side combustion gas temperature increases.
8. A heat transfer surface evaluation device according to claim 5;
   a control unit for controlling a soot blower for removing soot from the heat transfer surface based on the effective heat transfer area;
   A controller.
9. A combustion gas temperature estimation method for estimating the temperature of combustion gas supplied to at least one heat transfer surface for heat exchange with steam, comprising:
   obtaining a combustion gas temperature on the 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 the inlet side combustion gas enthalpy of the combustion gas on 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 the inlet-side combustion gas temperature of the heat transfer surface based on the inlet-side combustion gas enthalpy;
   A combustion gas temperature estimation method, comprising:
10. 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 estimated by the combustion gas temperature estimation method according to claim 9, and and calculating an effective heat transfer area of the heat transfer surface based on the heat absorption amount.
11. Based on the effective heat transfer area calculated by the heat transfer surface evaluation method according to claim 10, antifouling agent added to the boiler for generating the combustion gas, or maintenance timing of the heat transfer surface A heat transfer surface management method, further comprising a step of managing at least one of

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