Flow path resistance state monitoring device and flow path resistance state monitoring method
The flow path resistance state monitoring device corrects differential pressure measurements using gas flow rate ratios to account for variations, ensuring accurate monitoring and timely maintenance in boiler plants.
Patent Information
- Application Number
- JP2021056640
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-03-30
- Publication Date
- 2025-07-31
- Estimated Expiration
- 2041-03-30
AI Technical Summary
Existing flow path resistance monitoring devices in plants like boiler plants struggle to accurately monitor the state of flow path resistance due to changes in gas flow rates, as differential pressure measurements are influenced by varying gas flow rates.
A flow path resistance state monitoring device and method that corrects actual differential pressure measurements using the ratio of actual gas amount to a planned gas amount, calculating a converted pressure to account for gas flow rate changes, allowing for appropriate monitoring over time.
Enables accurate monitoring of flow path resistance in equipment like heat recovery devices and reheaters by reducing the impact of gas flow rate variations, facilitating timely maintenance and efficient operation.
Smart Images
Figure 0007716210000001 
Figure 0007716210000002 
Figure 0007716210000003
Abstract
Description
Technical Field
[0001] The present disclosure relates to a flow path resistance state monitoring device and a flow path resistance state monitoring method.
Background Art
[0002] Patent Document 1 describes a monitoring device that monitors the scale generation status (the state related to the flow path resistance of the monitoring target device) of a heat transfer tube bundle (monitoring target device) provided in a heat exchanger provided in a flow path through which the exhaust gas of a boiler in a boiler plant flows, based on the differential pressure before and after the heat transfer tube bundle.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, in a plant such as a boiler plant, when monitoring the state related to the flow path resistance of a monitoring target device, such as the adhesion state of deposits and the deposition state of sediments on the monitoring target device, based on the differential pressure before and after the monitoring target device, which is the object of monitoring of the pressure loss, the differential pressure before and after the monitoring target device changes according to the flow rate of the gas passing through the monitoring target device. For this reason, in the monitoring device described in Patent Document 1, when the flow rate of the gas passing through the monitoring target device changes, it is impossible to appropriately monitor the state related to the flow path resistance of the monitoring target device.
[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a flow path resistance state monitoring device and a flow path resistance state monitoring method capable of appropriately monitoring the state related to the flow path resistance of a monitoring target device even when the flow rate of the gas passing through the monitoring target device changes.
Means for Solving the Problems
[0006] In order to achieve the above object, a flow path resistance state monitoring device according to at least one embodiment of the present disclosure includes: A flow path resistance state monitoring device for monitoring a state related to flow path resistance of a monitored device in a plant, an actual differential pressure acquisition unit configured to acquire an actual differential pressure, which is a value related to an actual measured value of the differential pressure across the monitored device; an actual gas amount acquiring unit configured to acquire an actual gas amount, which is a value related to the flow rate of gas passing through the monitored device; a converted pressure calculation unit configured to calculate a converted pressure of the actual differential pressure based on the planned gas amount in the monitored device by correcting the actual differential pressure acquired by the actual differential pressure acquisition unit using a ratio between the actual gas amount acquired by the actual gas amount acquisition unit and a predetermined planned gas amount; a converted pressure output unit configured to output time-series data of the converted pressure of the actual differential pressure calculated by the converted pressure calculation unit; Equipped with.
[0007] In order to achieve the above object, a flow path resistance state monitoring method according to at least one embodiment of the present disclosure includes: A flow path resistance state monitoring method for monitoring a state related to flow path resistance of a monitored device in a plant, comprising: an actual differential pressure acquisition step of acquiring an actual differential pressure, which is a value related to an actual measured value of the differential pressure across the monitored device; an actual gas amount acquisition step of acquiring an actual gas amount, which is a value related to the flow rate of gas passing through the monitored device; a converted pressure calculation step of calculating a converted pressure of the actual differential pressure based on the planned gas amount in the monitored device by correcting the actual differential pressure acquired in the actual differential pressure acquisition step using a ratio between the actual gas amount acquired in the actual gas amount acquisition step and a predetermined planned gas amount; a converted pressure output step configured to output time-series data of the converted pressure of the actual differential pressure calculated in the converted pressure calculation step; Equipped with. [Effects of the Invention]
[0008] According to at least one embodiment of the present disclosure, a flow path resistance state monitoring device and a flow path resistance state monitoring method are provided that are capable of appropriately monitoring the state of the flow path resistance of the monitored equipment even when the flow rate of gas passing through the monitored equipment changes. [Brief explanation of the drawings]
[0009]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.
[0011] FIG. 1 is a diagram showing a schematic configuration of a boiler plant 2 according to one embodiment. As shown in FIG. 1 , the boiler plant 2 includes a boiler 4, a denitration unit 5, an air preheater 6, a gas-gas heater (hereinafter referred to as "GGH") 8, a dust collector 10, an induced draft fan 12, a wet desulfurization unit 14, a chimney 16, a flow meter 18, differential pressure gauges 20 and 22, and a flow path resistance condition monitor 24. The GGH 8 includes a heat recovery unit 26 and a reheater 28, each of which is configured as a heat exchanger. The boiler 4 and the chimney 16 are connected by an exhaust gas line 29, and the exhaust gas line 29 is provided with, in order from upstream in the flow direction of the exhaust gas discharged from the boiler, the denitration unit 5, the air preheater 6, the heat recovery unit 26, the dust collector 10, the induced draft fan 12, the wet desulfurization unit 14, and the reheater 28.
[0012] The exhaust gas discharged from the boiler 4 (hereinafter simply referred to as "exhaust gas") is cooled to, for example, 120 to 170°C by heat exchange in the air preheater 6 after the nitrogen oxides are removed by the denitration device 5. The exhaust gas passing through the air preheater 6 is deprived of heat by a heat medium (for example, water) flowing through the heat transfer tubes constituting the heat recovery device 26 and cooled to, for example, 75 to 110°C, and then the dust in the exhaust gas is removed by the dust collector 10. After being further pressurized by the induced draft fan 12, the sulfur oxides are removed by the wet desulfurization device 14. Thus, the heat recovery device 26 is configured to heat the heat medium by indirect heat exchange between the exhaust gas of the boiler 4 and the heat medium.
[0013] The exhaust gas passing through the wet desulfurization device 14 usually has its temperature reduced to about 40 to 60°C and reaches a moisture saturation state. If this exhaust gas is directly discharged into the atmosphere from the chimney 16 as it is, white smoke will be generated. Therefore, it is heated to a temperature above the dew point temperature (for example, the dew point temperature of sulfuric acid) by the reheater 28 and then discharged from the chimney 16. A heat medium circulation line 30 constituted by heat transfer tubes is provided between the heat recovery device 26 and the reheater 28, and the heat medium is circulated between the heat recovery device 26 and the reheater 28 through the heat medium circulation line 30 by the heat medium circulation pump 32. Thus, the reheater 28 is configured to heat the exhaust gas after passing through the wet desulfurization device 14 to a temperature above the dew point using the heat medium heated by the heat recovery device 26.
[0014] The flowmeter 18 is configured to measure the flow rate of the exhaust gas flowing through the exhaust gas line 29. The flow rate of the exhaust gas measured by the flowmeter 18 corresponds to the flow rate of the exhaust gas passing through the heat recovery device 26 and also corresponds to the flow rate of the exhaust gas passing through the reheater 28. The differential pressure gauge 20 is configured to measure the differential pressure across the heat recovery device 26 in the exhaust gas line 29. The differential pressure across the heat recovery device 26 means the pressure obtained by subtracting the pressure at the outlet of the heat recovery device 26 in the exhaust gas line 29 (in the illustrated example, the pressure between the heat recovery device 26 and the dust collector 10 in the exhaust gas line 29) from the pressure at the inlet of the heat recovery device 26 in the exhaust gas line 29 (in the illustrated example, the pressure between the air preheater 6 and the heat recovery device 26 in the exhaust gas line 29). The differential pressure gauge 22 is configured to measure the differential pressure across the reheater 28 in the exhaust gas line 29. The differential pressure across the reheater 28 means the pressure obtained by subtracting the pressure at the outlet of the reheater 28 in the exhaust gas line 29 (in the illustrated example, the pressure between the reheater 28 and the chimney 16 in the exhaust gas line 29) from the pressure at the inlet of the reheater 28 in the exhaust gas line 29 (in the illustrated example, the pressure between the wet desulfurization device 14 and the reheater 28 in the exhaust gas line 29).
[0015] Based on the measurement results of the flowmeter 18, the measurement results of the differential pressure gauge 20, and the measurement results of the differential pressure gauge 22, the flow path resistance state monitoring device 24 monitors the state of the flow path resistance of the heat recovery device 26 as the first monitoring target device and the state of the flow path resistance of the reheater 28 as the second monitoring target device. The detailed configuration of the flow path resistance state monitoring device 24 will be described later.
[0016] According to the boiler plant 2, the temperature of the exhaust gas can be reduced by the heat recovery device 26, SO3 and heavy metals can be adsorbed onto the ash in the exhaust gas, and the adsorbed substances can be removed together with the ash by the dust collector 10. Also, the heat recovered by the heat recovery device 26 can be used to reheat the moisture-saturated gas that has exited the wet desulfurization device 14 in order to prevent white smoke from the chimney 16.
[0017] FIG. 2 is a diagram showing an example of the hardware configuration of the flow path resistance state monitoring device 24 shown in FIG. 1. FIG. 3 is a block diagram showing an example of the functional configuration of the flow path resistance state monitoring device 24 shown in FIGS. 1 and 2. FIG. 4 is a diagram showing an example of a monitoring flow using the flow path resistance state monitoring device 24 shown in FIG. 3.
[0018] As shown in FIG. 2, the flow path resistance state monitoring device 24 is configured by using a computer including, for example, a processor 72, a RAM (Random Access Memory) 74, a ROM (Read Only Memory) 76, an HDD (Hard Disk Drive) 78, an input I / F 80, and an output I / F 82, which are connected to each other via a bus 84. Note that the hardware configuration of the flow path resistance state monitoring device 24 is not limited to the above, and may be configured by a combination of a control circuit and a storage device. Further, the flow path resistance state monitoring device 24 is configured by a computer executing a program for realizing each function of the flow path resistance state monitoring device 24. The functions of each part in the flow path resistance state monitoring device 24 described below are realized, for example, by loading a program held in the ROM 76 into the RAM 74 and executing it by the processor 72, and by reading and writing data in the RAM 74 and the ROM 76. The flow path resistance state monitoring device 24 may be configured by a Distributed Control System (DCS) provided in the boiler plant 2.
[0019] As shown in FIG. 3, the flow path resistance state monitoring device 24 includes an actual differential pressure acquisition unit 34, an actual gas amount acquisition unit 36, a converted pressure calculation unit 38, a converted pressure output unit 40, a storage unit 42, and a storage period management unit 44. Hereinafter, the functions of each part of the flow path resistance state monitoring device 24 shown in FIG. 3 will be described using the monitoring flow shown in FIG. 4.
[0020] In S11, the actual differential pressure acquisition unit 34 acquires an actual differential pressure P1, which is a value related to an actual measured value p1 of the differential pressure before and after the heat recovery device 26 in the exhaust gas line 29, and also acquires an actual differential pressure P2, which is a value related to an actual measured value p2 of the differential pressure before and after the reheater 28 in the exhaust gas line 29. Here, the actual differential pressure P1 may be the actual measured value p1 of the differential pressure before and after the heat recovery device 26 measured by the differential pressure gauge 20, or may be a value calculated using the actual measured value p1 (for example, a moving average of the actual measured value p1, which will be described later). Furthermore, the actual differential pressure P2 may be the actual measured value p2 of the differential pressure before and after the heat recovery device 26 measured by the differential pressure gauge 22, or may be a value calculated using the actual measured value p2 (for example, a moving average of the actual measured value p2, which will be described later).
[0021] In S12, the actual gas amount obtaining unit 36 obtains, from the flowmeter 18, the actual gas amount F, which is a value related to the flow rate f of the exhaust gas passing through the heat recovery device 26. Here, the actual gas amount F is a value related to the flow rate f of the exhaust gas passing through the heat recovery device 26, and is also a value related to the flow rate f of the exhaust gas passing through the reheater 28. Note that the actual gas amount F may be the flow rate f of the exhaust gas itself, which is the measurement result of the flowmeter 18, or may be a value calculated using the flow rate f (for example, a moving average of the flow rate f, which will be described later).
[0022] In S13, the converted pressure calculation unit 38 calculates a converted pressure Px1 of the actual differential pressure P1 based on the planned gas volume F0 in the heat recovery unit 26 by correcting the actual differential pressure P1 acquired by the actual differential pressure acquisition unit 34 using the ratio (F / F0) of the actual gas volume F acquired by the actual gas volume acquisition unit 36 to a predetermined planned gas volume F0 as shown in the following equation (a). Px1=P1 / g(F / F0) (a) Here, g(F / F0) is a function of the ratio (F / F0). Although various empirical formulas can be used as the function g(x), it has been found that in practice it can be approximated as the following formula (b). g(x)=ax 2 (b) Here, a is a coefficient. That is, when a is 1, equation (a) becomes the following equation (c). Px1=P1 / (F / F0) 2(c) In this way, the converted pressure calculation unit 38 calculates the converted pressure Px1 of the actual differential pressure P1 based on the planned gas amount F0 in the heat recovery unit 26 by dividing the actual differential pressure P1 acquired by the actual differential pressure acquisition unit 34 by the square of the ratio between the actual gas amount F acquired by the actual gas amount acquisition unit 36 and the planned gas amount F0. The planned gas amount F0 may be stored in the memory unit 42 and read from the memory unit 42 when calculating the converted pressure Px1.
[0023] In addition, in S13, the converted pressure calculation unit 38 corrects the actual differential pressure P2 acquired by the actual differential pressure acquisition unit 34 using the ratio (F / F0) of the actual gas volume F acquired by the actual gas volume acquisition unit 36 to a predetermined planned gas volume F0, as shown in the following equation (d), to calculate a converted pressure Px2 of the actual differential pressure P2 based on the planned gas volume F0 in the heat recovery unit 26. Px2=P2 / (F / F0) 2 (d) In this way, the converted pressure calculation unit 38 calculates the converted pressure Px2 of the actual differential pressure P2 based on the planned gas volume F0 in the reheater 28 by dividing the actual differential pressure P2 acquired by the actual differential pressure acquisition unit 34 by the square of the ratio between the actual gas volume F acquired by the actual gas volume acquisition unit 36 and the planned gas volume F0. The planned gas volume F0 used in calculating each of the converted pressures Px1 and Px2 in S13 may be an actual measurement value (initial data measured during a test run or the like at the start of operation of the boiler 4) of the flow rate of the exhaust gas passing through the heat recovery device 26 (and the reheater 28) measured by the flow meter 18 when the boiler 4 is subjected to a test run at the start of operation of the heat recovery device 26 (and the reheater 28). This planned gas volume F0 is a constant value (constant) that does not depend on time when each of the converted pressures Px1 and Px2 is calculated in time series using the above formulas (a) or (c), and (d), respectively.
[0024] In S14, the converted pressure output unit 40 outputs the time-series data of the converted pressure Px1 calculated in S13 (see FIG. 5) and the time-series data of the converted pressure Px2 calculated in S13 (see FIG. 6) to a display device 46 such as a display. Here, in order to facilitate monitoring of the temporal trends of the state related to the flow path resistance of the heat recovery device 26 and the state related to the flow path resistance of the reheater 28, each of the time-series data of the converted pressure Px1 and the time-series data of the converted pressure Px2 output by the converted pressure output unit 40 may include a plurality of data points per day (for example, about 10 data points per day).
[0025] Here, the causes of the temporal changes in the pressure loss in each of the heat recovery device 26 and the reheater 28 will be described.
[0026] On the outer surface of the heat transfer tubes constituting the heat recovery device 26, ash contained in the exhaust gas flowing through the exhaust gas line 29 adheres and accumulates, and salts (such as ammonium chloride) contained in the exhaust gas adhere. In this case, the flow path area inside the heat recovery device 26 decreases due to the deposits and accumulations, and the flow path resistance of the heat recovery device 26 in the exhaust gas line 29 increases. Therefore, the differential pressure (pressure loss) across the heat recovery device 26 increases accordingly. Although the heat recovery device 26 is provided with an ash removal device (such as a soot blower) not shown in the drawings for removing the ash adhering to the heat transfer tubes, if the differential pressure across the heat recovery device 26 is greater than a predetermined planned value, it is considered that there is a malfunction due to a failure or the like in the ash removal device.
[0027] In addition, on the outer surface of the heat transfer tubes constituting the reheater 28, deposits (such as gypsum) of soluble salts due to scattered mist from an absorption tower (not shown) provided in the wet desulfurization device 14 adhere. In this case, the flow path area inside the reheater 28 decreases due to the deposits, and the flow path resistance of the reheater 28 in the exhaust gas line 29 increases. Therefore, the differential pressure (pressure loss) across the reheater 28 increases accordingly.
[0028] Next, the effects of the flow path resistance state monitoring device 24 will be described. In the above formula (c), the converted pressure Px1 of the actual differential pressure P1 of the heat recovery device 26 based on the planned gas volume F0 is a parameter that indicates the state of the flow path resistance of the heat recovery device 26. A higher converted pressure Px1 means a higher flow path resistance of the heat recovery device 26, and a lower converted pressure Px1 means a lower flow path resistance of the heat recovery device 26. Furthermore, the flow path resistance state monitoring device 24 corrects the actual differential pressure P1, which is a value related to the actual measured value p1 of the differential pressure before and after the heat recovery device 26, by the square of the ratio of the actual gas volume F, which is a value related to the flow rate f of the exhaust gas passing through the heat recovery device 26, to the planned gas volume F0. Therefore, even if the flow rate of the exhaust gas passing through the heat recovery device 26 changes, the effect of the change in the flow rate of the exhaust gas can be reduced, and the state of the flow path resistance of the heat recovery device 26 can be monitored appropriately over time.
[0029] Furthermore, in the above formula (d), the converted pressure Px2 of the actual differential pressure P2 of the reheater 28 based on the planned gas volume F0 is a parameter that indicates the state related to the flow path resistance of the reheater 28, where a higher converted pressure Px2 means a higher flow path resistance of the reheater 28, and a lower converted pressure Px2 means a lower flow path resistance of the reheater 28. Furthermore, the flow path resistance state monitoring device 24 corrects the actual differential pressure Px2, which is a value related to the actual measured value p2 of the differential pressure before and after the reheater 28, by the square of the ratio of the actual gas volume F, which is a value related to the flow rate f of the exhaust gas passing through the reheater 28, to the planned gas volume F0. Therefore, even if the flow rate of the exhaust gas passing through the reheater 28 changes, the effect of changes in the flow rate of the exhaust gas can be reduced, and the state related to the flow path resistance of the reheater 28 can be monitored appropriately over time.
[0030] 4 , the actual differential pressure P1 acquired by the actual differential pressure acquisition unit 34 may be an actual measurement value p1 of the differential pressure across the heat recovery device 26 measured during the period when the boiler 4 is operating at the rated load (more preferably, a period after a predetermined time, such as one hour, has elapsed since the load on the boiler 4 reached the rated load), or may be a value calculated using the actual measurement value p1. In this case, the actual gas amount F acquired by the actual gas amount acquisition unit 36 in S12 may be a flow rate f of the exhaust gas measured during the period when the boiler 4 is operating at the rated load (more preferably, a period after a predetermined time, such as one hour, has elapsed since the load on the boiler 4 reached the rated load), or may be a value calculated using the flow rate f.
[0031] This allows the flow path resistance of the heat recovery device 26 in the boiler plant 2 to be monitored appropriately over time, even when the flow rate of the exhaust gas from the boiler 4 changes. Furthermore, by using only data for the actual differential pressure P1 and the actual gas flow rate F during the period when the boiler 4 was operating at rated load, it is possible to easily accumulate data over a long period of time while suppressing an increase in the storage capacity of the storage unit 42 (e.g., adding a computer including a storage device), compared to using all data during the operation period of the boiler 4. Moreover, since an overshoot or the like may occur immediately after the load on the boiler 4 increases and reaches the rated load, the use of data obtained a predetermined time after the rated load was reached, as described above, allows the flow path resistance of the heat recovery device 26 in the boiler plant 2 to be monitored appropriately over time. Note that days on which the boiler 4 is not operating at rated load may be excluded from the calculation and evaluation of the converted pressure Px1.
[0032] In some embodiments, in S11 in the flow shown in FIG. 4, the actual differential pressure P2 acquired by the actual differential pressure acquisition unit 34 may be the measured value p2 of the differential pressure before and after the reheater 28 measured during the period when the boiler 4 is operating at the rated load (more preferably, the period after a predetermined time such as 1 hour has elapsed since the load of the boiler 4 reached the rated load), or a value calculated using the measured value p2. In this case, in S12, the actual gas amount F acquired by the actual gas amount acquisition unit 36 may be the flow rate f of the exhaust gas measured during the period when the boiler 4 is operating at the rated load (more preferably, the period after a predetermined time such as 1 hour has elapsed since the load of the boiler 4 reached the rated load), or a value calculated using the flow rate f.
[0033] Thereby, the state of the flow path resistance of the reheater 28 in the boiler plant 2 can be monitored appropriately over time even when the flow rate of the exhaust gas of the boiler 4 changes. Also, since overshoot or the like may occur immediately after the load of the boiler 4 increases and reaches the rated load, by using the data after a predetermined time has elapsed since reaching the rated load as described above, the state of the flow path resistance of the reheater 28 in the boiler plant 2 can be monitored appropriately over time. Note that days when the boiler 4 is not operating at the rated load may be excluded from the calculation and evaluation of the converted pressure Px2.
[0034] 4 , the actual differential pressure acquiring unit 34 may acquire, as the actual differential pressure P1, a moving average of the actual measured values p1 of the differential pressure across the heat recovery unit 26 measured during a period in which the boiler 4 is operating at the rated load (more preferably, a period after a predetermined time, such as one hour, has elapsed since the load on the boiler 4 reached the rated load). In this case, in S12, the actual gas amount acquiring unit 36 may acquire, as the actual gas amount F, a moving average of the flow rate f of the exhaust gas measured during a period in which the boiler 4 is operating at the rated load (more preferably, a period after a predetermined time, such as one hour, has elapsed since the load on the boiler 4 reached the rated load). Even when the boiler 4 is at rated load, the differential pressure across the heat recovery device 26 and the flow rate of the exhaust gas from the boiler 4 fluctuate slightly. Therefore, by obtaining a moving average (for example, a 5-minute moving average) for each of the actual measured value p1 of the differential pressure across the heat recovery device 26 and the flow rate f of the exhaust gas as described above, the state of the flow resistance of the heat recovery device 26 in the boiler plant 2 can be appropriately monitored even if the flow rate of the exhaust gas from the boiler 4 changes.
[0035] 4 , the actual differential pressure acquiring unit 34 may acquire, as the actual differential pressure P2, a moving average of the actual measured values p2 of the differential pressure across the reheater 28 measured during a period in which the boiler 4 is operating at the rated load (more preferably, a period after a predetermined time, such as one hour, has elapsed since the load on the boiler 4 reached the rated load). In this case, in S12, the actual gas amount acquiring unit 36 may acquire, as the actual gas amount F, a moving average of the flow rate f of the exhaust gas measured during a period in which the boiler 4 is operating at the rated load (more preferably, a period after a predetermined time, such as one hour, has elapsed since the load on the boiler 4 reached the rated load). Even when the boiler 4 is at rated load, the differential pressure across the reheater 28 and the flow rate of the exhaust gas from the boiler 4 fluctuate slightly. Therefore, by obtaining a moving average (for example, a 5-minute moving average) for each of the actual measured value p1 of the differential pressure across the reheater 28 and the flow rate f of the exhaust gas as described above, the state of the flow path resistance of the reheater 28 in the boiler plant 2 can be appropriately monitored even if the flow rate of the exhaust gas from the boiler 4 changes.
[0036] In some embodiments, for example, the storage unit 42 shown in FIG. 3 stores the time-series data of the actual differential pressure P1 acquired by the actual differential pressure acquisition unit 34, the time-series data of the actual differential pressure P2 acquired by the actual differential pressure acquisition unit 34, the time-series data of the actual gas amount F acquired by the actual gas amount acquisition unit 36, the time-series data of the converted pressure Px1 calculated by the converted pressure calculation unit 38, the time-series data of the converted pressure Px2 calculated by the converted pressure calculation unit 38, and the planned gas amount F0 described above.
[0037] In this case, the storage period management unit 44 may manage the storage period of each of the time-series data stored in the storage unit 42 such that the storage period of the time-series data of the actual differential pressure P1 and the storage period of the time-series data of the actual gas amount F in the storage unit 42 are shorter than the storage period of the time-series data of the converted pressure Px1 in the storage unit 42. Also, the storage period management unit 44 may manage the storage period of each of the time-series data stored in the storage unit 42 such that the storage period of the time-series data of the actual differential pressure P2 and the storage period of the time-series data of the actual gas amount F in the storage unit 42 are shorter than the storage period of the time-series data of the converted pressure Px2 in the storage unit 42.
[0038] For example, the storage period management unit 44 may be configured to automatically delete from the storage unit 42 the data for which the corresponding storage period has elapsed for each of the actual differential pressures P1, P2, and the actual gas amount F, and not automatically delete from the storage unit 42 the time-series data of the converted pressure Px1 and the time-series data of the converted pressure Px2 stored in the storage unit 42.
[0039] Also, for example, the storage period management unit 44 may set the storage period of the time-series data of the converted pressure Px1 in the storage unit 42 to a period of one month or more, and set the storage period of the time-series data of the actual differential pressure P1 and the storage period of the time-series data of the actual gas amount F in the storage unit 42 to a period of about one to several weeks (for example, a period of one week or more and less than one month). Further, the storage period management unit 44 may set the storage period of the time-series data of the converted pressure Px2 in the storage unit 42 to a period of one month or more, and set the storage period of the time-series data of the actual differential pressure P2 and the storage period of the time-series data of the actual gas amount F in the storage unit 42 to a period of about one to several weeks (for example, a period of one week or more and less than one month). In this case, the storage period management unit 44 is configured to automatically delete from the storage unit 42 when the corresponding storage period has elapsed for each of the converted pressures Px1, Px2, the actual differential pressures P1, P2, and the actual gas amount F in the storage unit 42.
[0040] In this way, by making the storage period of the time-series data of the actual differential pressure P1 and the storage period of the time-series data of the actual gas amount F shorter than the storage period of the time-series data of the converted pressure Px1 necessary for monitoring the state of the flow path resistance of the heat recovery device 26 of the boiler plant 2, while suppressing an increase in the storage capacity of the storage unit 42 (for example, adding a computer including a storage device), it is possible to long-term and appropriately monitor the state of the flow path resistance of the heat recovery device 26 of the boiler plant 2. Therefore, it is possible to long-term and appropriately monitor the state of the flow path resistance of the heat recovery device 26 with a simple and low-cost configuration.
[0041] Also, by making the storage period of the time-series data of the actual differential pressure P2 and the storage period of the time-series data of the actual gas amount F shorter than the storage period of the time-series data of the converted pressure Px2 necessary for monitoring the state of the flow path resistance of the reheater 28 of the boiler plant 2, while suppressing an increase in the storage capacity of the storage unit 42, it is possible to long-term and appropriately monitor the state of the flow path resistance of the reheater 28 of the boiler plant 2. Therefore, it is possible to long-term and appropriately monitor the state of the flow path resistance of the reheater 28 with a simple and low-cost configuration.
[0042] In some embodiments, when the converted pressure Px1 calculated in S13 exceeds a predetermined threshold value, the alarm signal generation unit 48 shown in FIG. 3 may generate an alarm signal for prompting maintenance such as an operation of removing ash adhering to the ash of the heat recovery device 26, or may generate an alarm signal for prompting maintenance of an ash removal device (such as a soot blower) for removing the ash adhering to the heat recovery device 26. Further, when the converted pressure Px2 calculated in S13 exceeds a predetermined threshold value, the alarm signal generation unit 48 may generate an alarm signal for prompting maintenance such as an operation of removing soluble salts such as gypsum deposited on the reheater 28. These alarm signals may be signals for outputting a display prompting the above-mentioned maintenance to the display device 46, or may be signals for prompting the above-mentioned maintenance using other means such as voice. By generating an alarm signal as described above, it becomes possible to perform maintenance on the heat recovery device 26 and the reheater 28 at an appropriate timing.
[0043] The present disclosure is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms. For example, in the above-described embodiments, the heat recovery device 26 and the reheater 28 are exemplified as monitoring target devices for monitoring the state related to the flow path resistance. However, the monitoring target devices are not limited to these, and may be other devices in the boiler plant 2 whose pressure loss may change over time, such as the flue of the boiler 4 or other pipes. Further, the monitoring target devices are not limited to the devices constituting the boiler plant 2, and may be devices constituting a chemical plant that produces chemical substances or a power generation plant that generates power.
[0044] Further, for example, in the embodiment shown in FIG. 1, the actual differential pressures P1 and P2 acquired by the actual differential pressure acquisition unit 34 were values based on the measurement results of the differential pressure gauges 20 and 22. However, in other embodiments, the actual differential pressure P1 may be the differential pressure across the heat recovery device 26 obtained by subtracting the measurement result of the pressure gauge provided at the outlet of the heat recovery device 26 from the measurement result of the pressure gauge provided at the inlet of the heat recovery device 26 in the exhaust gas line 29, or a value calculated using the differential pressure across the heat recovery device 26. The actual differential pressure P2 may be the differential pressure across the reheater 28 obtained by subtracting the measurement result of the pressure gauge provided at the outlet of the reheater 28 from the measurement result of the pressure gauge provided at the inlet of the reheater 28 in the exhaust gas line 29, or a value calculated using the differential pressure across the reheater 28.
[0045] Further, the actual gas amount F acquired by the actual gas amount acquisition unit 36 is not limited to the flow rate of the exhaust gas in the exhaust gas line 29 measured by the flow meter 18. For example, it may be the flow rate of the air (combustion air) supplied to the boiler 4, or the air volume of the induced draft fan 12. Also, in the embodiment shown in FIG. 1, the flow meter 18 was provided at a position between the air preheater 6 and the heat recovery device 26, but the flow meter 18 may be provided at other positions in the exhaust gas line 29.
[0046] Also, in the above-described embodiment, the flow path resistance state monitoring device 24 was configured to monitor the state related to the flow path resistance of the heat recovery device 26 and the state related to the flow path resistance of the reheater 28. However, the flow path resistance state monitoring device 24 may monitor only the state related to the flow path resistance of the heat recovery device 26 without monitoring the state related to the flow path resistance of the reheater 28, or may monitor only the state related to the flow path resistance of the reheater 28 without monitoring the state related to the flow path resistance of the heat recovery device 26.
[0047] The content described in each of the above embodiments is understood as follows, for example.
[0048] (1) The flow path resistance state monitoring device (for example, the above-described flow path resistance state monitoring device 24) according to at least one embodiment of the present disclosure is A flow path resistance state monitoring device for monitoring a state related to the flow path resistance of a monitored device (for example, the heat recovery device 26 or the reheater 28) of a plant (for example, the boiler plant 2 described above), an actual differential pressure acquisition unit (for example, the above-mentioned actual differential pressure acquisition unit 34) configured to acquire an actual differential pressure (for example, the above-mentioned actual differential pressure P1 or actual differential pressure P2) which is a value related to an actual measured value (for example, the above-mentioned actual measured value p1 or actual measured value p2) of the differential pressure before and after the monitoring target device; an actual gas amount acquiring unit (for example, the above-mentioned actual gas amount acquiring unit 36) configured to acquire an actual gas amount (for example, the above-mentioned actual gas amount F) which is a value related to the flow rate of gas passing through the monitored device (for example, the above-mentioned flow rate f); a converted pressure calculation unit (for example, the above-mentioned converted pressure calculation unit 38) configured to calculate a converted pressure (for example, the above-mentioned converted pressure Px1 or Px2) of the actual differential pressure based on the planned gas amount in the monitored device by correcting the actual differential pressure acquired by the actual differential pressure acquisition unit using a ratio between the actual gas amount acquired by the actual gas amount acquisition unit and a predetermined planned gas amount (for example, the above-mentioned planned gas amount F0); a converted pressure output unit (for example, the above-described converted pressure output unit 40) configured to output time-series data of the converted pressure of the actual differential pressure calculated by the converted pressure calculation unit; Equipped with.
[0049] In the flow path resistance state monitoring device described in (1) above, the converted pressure of the actual differential pressure of the monitored device based on the planned gas amount is a parameter that indicates the state of the flow path resistance of the monitored device, where a higher converted pressure means a higher flow path resistance of the monitored device, and a lower converted pressure means a lower flow path resistance of the monitored device. Furthermore, in the flow path resistance state monitoring device, the actual differential pressure, which is a value related to the actual measured value of the differential pressure across the monitored device, is corrected using the ratio of the actual gas amount to the planned gas amount, which is a value related to the flow rate of gas passing through the monitored device. Therefore, even if the flow rate of gas passing through the monitored device changes, the effect of the change in gas flow rate can be reduced, and the state of the flow path resistance of the monitored device can be monitored appropriately over time.
[0050] (2) In some embodiments, in the flow path resistance state monitoring device described in (1), The converted pressure calculation unit is configured to calculate a converted pressure of the actual differential pressure based on the planned gas amount in the monitored device by dividing the actual differential pressure acquired by the actual differential pressure acquisition unit by a function of the ratio between the actual gas amount acquired by the actual gas amount acquisition unit and the planned gas amount.
[0051] According to the flow path resistance status monitoring device described in (2) above, the actual differential pressure, which is a value relating to the actual measured value of the differential pressure before and after the monitored equipment, is corrected by dividing it by a function of the ratio between the actual gas volume, which is a value relating to the flow rate of gas passing through the monitored equipment, and the planned gas volume.Therefore, even if the flow rate of gas passing through the monitored equipment changes, the effect of the change in gas flow rate can be reduced, and the flow path resistance status of the monitored equipment can be monitored appropriately over time.
[0052] (3) In some embodiments, in the flow path resistance state monitoring device described in (1) or (2), The converted pressure calculation unit is configured to calculate a converted pressure of the actual differential pressure based on the planned gas amount in the monitored device by dividing the actual differential pressure acquired by the actual differential pressure acquisition unit by the square of the ratio between the actual gas amount acquired by the actual gas amount acquisition unit and the planned gas amount.
[0053] According to the flow path resistance status monitoring device described in (3) above, the actual differential pressure, which is a value relating to the actual measured value of the differential pressure before and after the monitored equipment, is corrected by dividing it by the square of the ratio between the actual gas volume, which is a value relating to the flow rate of gas passing through the monitored equipment, and the planned gas volume.Therefore, even if the flow rate of gas passing through the monitored equipment changes, the effect of the change in gas flow rate can be reduced, and the flow path resistance status of the monitored equipment can be monitored appropriately over time.
[0054] (4) In some embodiments, in the flow path resistance state monitoring device according to any one of (1) to (3), The planned gas amount is an actual measurement value obtained by measuring a value relating to the flow rate of the gas passing through the monitored equipment at the start of operation of the monitored equipment.
[0055] The flow path resistance state monitoring device described in (4) above can calculate and output a converted pressure of the actual differential pressure based on the gas flow rate at the start of operation of the monitored equipment, making it easy to appropriately monitor changes in the flow path resistance state of the monitored equipment from the start of operation.
[0056] (5) In some embodiments, in the flow path resistance state monitoring device described in any one of (1) to (4), the plant is a boiler plant (e.g., the boiler plant 2 described above) including a boiler (e.g., the boiler 4 described above); the monitored device is a heat exchanger (for example, the heat recovery device 26 or the reheater 28) provided in an exhaust gas line (for example, the exhaust gas line 29) through which exhaust gas from the boiler flows, the actual differential pressure acquisition unit is configured to acquire the actual differential pressure during a period in which the boiler is operating at a rated load, The actual gas amount obtaining unit is configured to obtain the actual gas amount during a period when the boiler is operating at a rated load.
[0057] According to the flow path resistance state monitoring device described in (5) above, the state relating to the flow path resistance of a heat exchanger in a boiler plant can be monitored appropriately over time even if the flow rate of exhaust gas from the boiler changes.
[0058] (6) In some embodiments, in the flow path resistance state monitoring device described in (5), the actual differential pressure acquisition unit is configured to acquire, as the actual differential pressure, a moving average of actual measured values of differential pressure across the heat exchanger during a period in which the boiler is operating at a rated load; The actual gas amount obtaining unit is configured to obtain, as the actual gas amount, a moving average of values related to the flow rate of the exhaust gas passing through the heat exchanger during a period when the boiler is operating at a rated load.
[0059] Even at the rated load of the boiler, the differential pressure across the heat exchanger and the flow rate of the exhaust gas from the boiler fluctuate slightly. Therefore, by obtaining moving averages for each of the differential pressure across the heat exchanger and the flow rate of the exhaust gas as described in (6) above, the condition of the flow path resistance of the heat exchanger in the boiler plant can be appropriately monitored even if the flow rate of the exhaust gas from the boiler changes.
[0060] (7) In some embodiments, in the flow path resistance state monitoring device described in (5) or (6), the actual differential pressure acquisition unit is configured to acquire the actual differential pressure after a predetermined time has elapsed since the load of the boiler reached the rated load, The actual gas amount obtaining unit is configured to obtain the actual gas amount after a predetermined time has elapsed since the load on the boiler reached the rated load.
[0061] According to the flow path resistance state monitoring device described in (7) above, overshooting and the like may occur immediately after the boiler load increases and reaches the rated load. Therefore, by using data obtained after a predetermined time has elapsed since the rated load was reached as described in (7) above, the state of the flow path resistance of the heat exchanger in the boiler plant can be monitored over time and appropriately.
[0062] (8) In some embodiments, in the flow path resistance state monitoring device according to any one of (1) to (7), a storage unit (for example, the storage unit 42) that stores time series data of the actual differential pressure acquired by the actual differential pressure acquisition unit, time series data of the actual gas amount acquired by the actual gas amount acquisition unit, and time series data of the converted pressure calculated by the converted pressure calculation unit; a storage period management unit (for example, the above-mentioned storage period management unit 44) that manages the storage period of each of the time series data in the storage unit so that the storage period of the time series data of the actual differential pressure and the storage period of the time series data of the actual gas amount in the storage unit are each shorter than the storage period of the time series data of the converted pressure in the storage unit; Further provided with:
[0063] According to the flow path resistance state monitoring device described in (8) above, by shortening the storage period for the time series data of the actual differential pressure and the time series data of the actual gas volume compared to the storage period for the time series data of the converted pressure required to monitor the flow path resistance state of the monitored equipment in the plant, it is possible to appropriately monitor the flow path resistance state of the monitored equipment in the plant over a long period of time while suppressing an increase in the storage capacity of the storage unit. Therefore, it is possible to appropriately monitor the flow path resistance state of the monitored equipment over a long period of time with a simple and low-cost configuration.
[0064] (9) A flow path resistance state monitoring method according to at least one embodiment of the present disclosure, A flow path resistance state monitoring method for monitoring a state related to flow path resistance of a monitored device (e.g., the heat recovery device 26 or the reheater 28) of a plant (e.g., the boiler plant 2), comprising: an actual differential pressure acquisition step of acquiring an actual differential pressure (e.g., the above-mentioned actual differential pressure P1 or actual differential pressure P2) which is a value related to an actual measured value (e.g., the above-mentioned actual measured value p1 or actual measured value p2) of the differential pressure before and after the monitoring target device; an actual gas amount acquisition step of acquiring an actual gas amount (e.g., the above-mentioned actual gas amount F), which is a value related to the flow rate of gas passing through the monitored device (e.g., the above-mentioned flow rate f); a converted pressure calculation step of calculating a converted pressure (e.g., the above-mentioned converted pressure Px1 or Px2) of the actual differential pressure based on the planned gas amount in the monitored device by correcting the actual differential pressure acquired in the actual differential pressure acquisition step using a ratio between the actual gas amount acquired in the actual gas amount acquisition step and a predetermined planned gas amount (e.g., the above-mentioned planned gas amount F0); a converted pressure output step configured to output time-series data of the converted pressure of the actual differential pressure calculated in the converted pressure calculation step; Equipped with.
[0065] According to the flow path resistance state monitoring method described in (9) above, the converted pressure of the actual differential pressure of the monitored device based on the planned gas amount is a parameter that indicates the state of the flow path resistance of the monitored device, where a higher converted pressure means a higher flow path resistance of the monitored device, and a lower converted pressure means a lower flow path resistance of the monitored device. Furthermore, in the flow path resistance state monitoring method, the actual differential pressure, which is a value related to the actual measured value of the differential pressure across the monitored device, is corrected using the ratio of the actual gas amount to the planned gas amount, which is a value related to the flow rate of gas passing through the monitored device. Therefore, even if the flow rate of gas passing through the monitored device changes, the effect of the change in gas flow rate can be reduced, and the state of the flow path resistance of the monitored device can be monitored appropriately over time. [Explanation of symbols]
[0066] 2. Boiler plant 4 boilers 5 Denitration equipment 6. Air preheater 10 Dust collector 12 Attractive Fan 14 Wet desulfurization equipment 16 Chimney 18 Flow meter 20,22 Differential pressure gauge 24 Flow path resistance condition monitoring device 26 Heat recovery unit 28 Reheater 29 Exhaust gas line 30 Heat medium circulation line 32 Heat medium circulation pump 34 Actual differential pressure acquisition section 36 Actual gas volume acquisition unit 38 Conversion pressure calculation section 40 Converted pressure output section 42 Storage section 44 Retention Period Management Department 46 Display device 48 Alarm signal generator 72 processors 74 RAM 76 ROM 78 HDD 80 Input I / F 82 Output I / F 84 Bus
Claims
1. A flow path resistance state monitoring device for monitoring the state of the flow path resistance of a plant's monitored equipment, comprising: An actual differential pressure acquisition unit configured to acquire an actual differential pressure, which is a value related to the actually measured value of the differential pressure before and after the monitored equipment; An actual gas amount acquisition unit configured to acquire an actual gas amount, which is a value related to the flow rate of the gas passing through the monitored equipment; A converted pressure calculation unit configured to calculate a converted pressure of the actual differential pressure based on the planned gas amount in the monitored equipment by correcting the actual differential pressure acquired by the actual differential pressure acquisition unit using the ratio of the actual gas amount acquired by the actual gas amount acquisition unit to a predetermined planned gas amount; A converted pressure output unit configured to output time-series data of the converted pressure of the actual differential pressure calculated by the converted pressure calculation unit; Comprising: The plant is a boiler plant equipped with a boiler; The monitored equipment is a heat exchanger provided in an exhaust gas line through which the exhaust gas of the boiler flows; The actual differential pressure acquisition unit is configured to acquire, as the actual differential pressure, a moving average of the actually measured values of the differential pressure before and after the heat exchanger during the period when the boiler is operating at rated load; The actual gas amount acquisition unit is configured to acquire, as the actual gas amount, a moving average of the values related to the flow rate of the gas passing through the heat exchanger during the period when the boiler is operating at rated load; The converted pressure calculation unit is configured to calculate time-series data of the moving average of the converted pressure of the actual differential pressure based on the moving average of the actually measured values of the differential pressure before and after the heat exchanger and the moving average of the values related to the flow rate of the gas passing through the heat exchanger; The converted pressure output unit is configured to output the time-series data of the moving average of the converted pressure of the actual differential pressure to a display device as a graph with time on the first axis and the converted pressure of the actual differential pressure on the second axis, together with a threshold value of the converted pressure of the actual differential pressure; The time-series data displayed in the graph includes a plurality of data points in one day; The flow path resistance state monitoring device further comprises an alarm signal generation unit configured to generate an alarm signal and display it on the display device when the time-series data calculated by the converted pressure output unit exceeds the threshold value; Flow path resistance state monitoring device.
2. The conversion pressure calculation unit is configured to calculate a conversion pressure of the actual differential pressure based on the planned gas amount in the device to be monitored by dividing the actual differential pressure acquired by the actual differential pressure acquisition unit by a function of a ratio between the actual gas amount acquired by the actual gas amount acquisition unit and the planned gas amount. The flow path resistance state monitoring device according to claim 1.
3. The conversion pressure calculation unit is configured to calculate a conversion pressure of the actual differential pressure based on the planned gas amount in the device to be monitored by dividing the actual differential pressure acquired by the actual differential pressure acquisition unit by the square of a ratio between the actual gas amount acquired by the actual gas amount acquisition unit and the planned gas amount. The flow path resistance state monitoring device according to claim 1 or 2.
4. The planned gas amount is a measured value obtained by measuring a value related to the flow rate of the gas passing through the device to be monitored at the start of operation of the device to be monitored. The flow path resistance state monitoring device according to any one of claims 1 to 3.
5. The actual differential pressure acquisition unit is configured to acquire the actual differential pressure after a predetermined time has elapsed since the load of the boiler reached the rated load. The actual gas amount acquisition unit is configured to acquire the actual gas amount after a predetermined time has elapsed since the load of the boiler reached the rated load. The flow path resistance state monitoring device according to any one of claims 1 to 4.
6. A storage unit that stores time-series data of the actual differential pressure acquired by the actual differential pressure acquisition unit, time-series data of the actual gas amount acquired by the actual gas amount acquisition unit, and time-series data of the conversion pressure calculated by the conversion pressure calculation unit; A storage period management unit that manages the storage period of each of the time-series data in the storage unit such that the storage period of the time-series data of the actual differential pressure and the storage period of the time-series data of the actual gas amount in the storage unit are each shorter than the storage period of the time-series data of the conversion pressure in the storage unit; The flow path resistance state monitoring device according to any one of claims 1 to 5, further comprising:
7. A flow path resistance state monitoring method for monitoring a state related to the flow path resistance of a device to be monitored in a plant, comprising: An actual differential pressure acquisition step of acquiring an actual differential pressure which is a value related to the measured value of the differential pressure before and after the device to be monitored; An actual gas amount acquisition step of acquiring an actual gas amount which is a value related to the flow rate of the gas passing through the device to be monitored; A conversion pressure calculation step of calculating a converted pressure of the actual differential pressure based on the planned gas amount in the equipment to be monitored by correcting the actual differential pressure obtained in the actual differential pressure acquisition step using a ratio between the actual gas amount obtained in the actual gas amount acquisition step and a predetermined planned gas amount; A converted pressure output step configured to output time-series data of the converted pressure of the actual differential pressure calculated in the converted pressure calculation step; comprising; The plant is a boiler plant including a boiler; The equipment to be monitored is a heat exchanger provided in an exhaust gas line through which the exhaust gas of the boiler flows; In the actual differential pressure acquisition step, as the actual differential pressure, a moving average of measured values of the differential pressure before and after the heat exchanger during a period when the boiler is operating at a rated load is acquired; In the actual gas amount acquisition step, as the actual gas amount, a moving average of values related to the flow rate of the gas passing through the heat exchanger during a period when the boiler is operating at a rated load is acquired; In the converted pressure calculation step, based on the moving average of the measured values of the differential pressure before and after the heat exchanger and the moving average of the values related to the flow rate of the gas passing through the heat exchanger, time-series data of the moving average of the converted pressure of the actual differential pressure is calculated; In the converted pressure output step, the time-series data of the moving average of the converted pressure of the actual differential pressure is output to a display device in order to be displayed as a graph with time on the first axis and the converted pressure of the actual differential pressure on the second axis, together with a threshold value of the converted pressure of the actual differential pressure; The time-series data displayed in the graph includes a plurality of data points in one day; The flow path resistance state monitoring method further includes an alarm signal generation step of generating an alarm signal and displaying it on the display device when the time-series data calculated in the converted pressure output step exceeds the threshold value; Flow path resistance state monitoring method.
Citation Information
Patent Citations
Water level control device for boiler
JP1999287405A
Heat-transfer tube monitoring device
JP2010255972A
Combined cycle power generation plant, and its operation method and modification method
JP2019027399A