JP2021021554A - Boiler control device, boiler system, power generation plant, and boiler control method - Google Patents

Abstract

To provide a boiler control device or the like capable of more appropriately controlling a fuel flow rate to be fed to a boiler with respect to a heat reception amount of varying heat from the outside such as solar heat.SOLUTION: A boiler control device is a control device for a boiler generating steam from feed water. The boiler control device comprises: a first control signal acquisition unit acquiring a first control signal of a fuel flow rate of a fuel to be supplied to a boiler; a heat reception amount information acquisition unit configured to acquire heat reception amount information on the heat reception amount of varying heat from the outside; a correction signal acquisition unit configured to convert the heat reception amount shown by the heat reception amount information acquired by the heat reception amount information acquisition unit into a fuel flow rate to acquire a correction signal for correcting the first control signal; and a fuel flow rate command unit configured to output a fuel flow rate command for controlling a fuel flow rate on the basis of the first control signal and the correction signal added with a delay element.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a boiler control device, a boiler system, a power plant, and a boiler control method.

A power plant is known in which a heat medium is heated by the condensed heat of sunlight (solar heat) and used for heating the feed water of a boiler. Such a power plant is advantageous in that it can reduce the fuel consumption and carbon dioxide emissions of the boiler. However, in such a configuration, the amount of heat received by the heat medium from the solar heat fluctuates due to the change in the amount of solar radiation, and the temperature of the feed water of the boiler fluctuates. In a power plant, it is necessary to suppress the influence of such temperature fluctuations of water supply in order to ensure the life of constituent equipment and the stability of steam generated from the boiler.

Patent Document 1 is a composite of solar heat and a fuel boiler including a boiler that heats the water supply by combustion gas and a CSP device that heats the water supply by solar heat to generate CSP steam by solar power collection (CSP: Concentrating Solar Power). The power generation system is disclosed. In this system, the CSP steam is branched and supplied to the inlet and outlet of the boiler, and the inlet steam temperature (main steam temperature) of the steam turbine is adjusted by adjusting the ratio of the supply. In addition, this system adjusts the main steam temperature by controlling the ratio of CSP steam supply according to the solar radiation intensity and the CSP steam temperature.

Japanese Unexamined Patent Publication No. 2016-160775

In the configuration disclosed in Patent Document 1, when the amount of heat received from solar heat fluctuates, the ratio of CSP steam supply is controlled. However, such control does not control the flow rate of fuel supplied to the boiler in response to fluctuations in the amount of heat received from solar heat.

In addition, Patent Document 1 suggests that the fuel flow rate is controlled based on the main steam temperature. According to such a configuration, when the main steam temperature fluctuates due to the fluctuation of the amount of heat received from the solar heat, the fuel flow rate is controlled so as to increase or decrease the fuel flow rate supplied to the boiler.

However, since there is a time lag between the fluctuation of the amount of heat received from the solar heat and the fluctuation of the main steam temperature, it is appropriate because of the followability of the control of the fuel flow rate supplied to the boiler to the fluctuation of the amount of heat received from the solar heat. There is a risk that the fuel flow rate cannot be controlled. For example, even if the amount of heat received from solar heat increases sharply, the control for reducing the fuel flow rate may be delayed, and the fuel consumption of the boiler may not be sufficiently reduced.

Further, even if the main steam temperature can be adjusted within the permissible range, there is a possibility that the steam temperature or the water supply temperature of the heat exchanger on the upstream side is not adjusted within the permissible range as the specifications of the heat exchanger. .. That is, in the configuration in which the fuel flow rate supplied to the boiler is controlled based on the main steam temperature, the temperature distribution in the boiler may not be sufficiently optimized.

In view of the above circumstances, the present disclosure provides a boiler control device and the like capable of more appropriately controlling the fuel flow rate supplied to the boiler with respect to the amount of heat received from the outside such as solar heat. With the goal.

The boiler control device according to the present disclosure is
A boiler control device that produces steam from water supply.
The first control signal for acquiring the first control signal generated based on the base fuel flow rate signal generated based on the output target command and the third control signal according to the boiler load condition for the fuel flow rate of the fuel supplied to the boiler. Acquisition department and
A heat receiving amount information acquisition unit configured to acquire heat receiving amount information regarding the heat receiving amount of fluctuating heat from the outside,
A correction signal acquisition unit configured to convert the heat reception amount indicated by the heat reception amount information acquired by the heat reception amount information acquisition unit into the fuel flow rate and acquire a correction signal for correcting the first control signal. ,
A fuel flow rate command unit configured to output a fuel flow rate command for controlling the fuel flow rate based on the first control signal and the correction signal to which a delay element is added.
To be equipped.

The boiler system related to this disclosure is
With the above boiler control device
A heat medium circulation flow path for circulating a heat medium that receives fluctuating heat from the outside,
A boiler that includes an economizer, a primary superheater, and a secondary superheater, and generates steam by heating the water supply that has exchanged heat with the heat medium by burning fuel.
To be equipped.

The power plant according to this disclosure is
With the above boiler system,
A steam turbine that is rotationally driven by the steam generated by the boiler system,
A generator connected to the steam turbine and generating electricity according to the rotation of the steam turbine.
To be equipped.

The boiler control method according to the present disclosure is described.
It is a control method of a boiler that generates steam from water supply.
The step of acquiring the first control signal generated based on the base fuel flow rate signal generated based on the output target command and the third control signal according to the boiler load condition, and the step of acquiring the fuel flow rate of the fuel supplied to the boiler.
The step of acquiring heat reception amount information regarding the heat reception amount of fluctuating heat from the outside, and
A step of converting the heat receiving amount indicated by the acquired heat receiving amount information into the fuel flow rate and acquiring a correction signal for correcting the first control signal.
A step of outputting a fuel flow rate command for controlling the fuel flow rate based on the first control signal and the correction signal to which a delay element is added.
To be equipped.

According to the present disclosure, it is possible to provide a boiler control device and the like capable of more appropriately controlling the flow rate of fuel supplied to the boiler with respect to the amount of heat received that fluctuates from the outside such as solar heat.

It is a schematic block diagram of the boiler system which concerns on one Embodiment. It is a schematic block diagram of the power plant which concerns on one Embodiment. It is a block diagram which shows the structure about the fuel flow rate control of the control device of the boiler which concerns on one Embodiment. It is a conceptual diagram for demonstrating the temperature distribution in the boiler which concerns on a comparative example. It is a figure for demonstrating the correction of the 3rd control signal of the control device of the boiler which concerns on one Embodiment, and is a conceptual diagram which shows the time transition of the steam temperature of a boiler. It is a figure for demonstrating the correction of the 3rd control signal of the control device of the boiler which concerns on one Embodiment, and is a conceptual diagram which shows the time transition of the fuel flow rate to supply to a boiler. It is a block diagram which shows the structure about the opening degree control of the damper of the boiler control device which concerns on one Embodiment. It is a figure for demonstrating the opening degree control of the damper of the boiler control device which concerns on one Embodiment, and is a conceptual diagram which shows the time transition of the outlet water supply temperature of an economizer. It is a flowchart which shows an example of the control process executed by the control device of the boiler which concerns on one Embodiment.

Hereinafter, some embodiments will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the invention, but are merely explanatory examples. ..
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the state of existence.
For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or chamfering within a range in which the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

(Outline configuration of boiler system)
Hereinafter, a schematic configuration of the boiler system 1 according to the embodiment will be described. In this embodiment, as an example of receiving fluctuating heat from the outside, a boiler system 1 that receives solar heat from condensed sunlight will be described. FIG. 1 is a schematic configuration diagram of a boiler system 1 according to an embodiment. This figure shows the combustion gas system of the boiler system 1, and the configurations of the water supply system, the steam system, the circulation flow path of the heat medium that receives solar heat, and the like are omitted. These configurations will be described later.

As shown in FIG. 1, the boiler system 1 includes a coal-fired boiler (boiler) 10 that generates steam and a boiler control device 100 that controls the boiler 10. The boiler 10 of the present embodiment uses pulverized coal obtained by crushing coal (carbon-containing solid fuel) as pulverized fuel, and the pulverized fuel is burned by combustion burners 21, 22, 23, 24, 25. Coal-fired (pulverized coal-fired). ) Boiler 10. The boiler 10 of the present embodiment recovers the heat generated by combustion and exchanges heat with water supply or steam to generate superheated steam. In the following description, the upper and upper sides indicate the upper side in the vertical direction, and the lower and lower parts indicate the lower side in the vertical direction.

The boiler 10 has a fireplace 11, a combustion device 12, and a flue 13. The fireplace 11 has a hollow shape of a square cylinder and is installed along the vertical direction. The fireplace wall (heat transfer tube) constituting the fireplace 11 is composed of a plurality of evaporation pipes and fins connecting them, and the temperature of the fireplace wall is obtained by exchanging heat generated by combustion of pulverized fuel with water supply or steam. The rise is suppressed.

The combustion device 12 is provided on the lower side of the furnace wall constituting the fireplace 11. In the present embodiment, the combustion device 12 includes a plurality of combustion burners (for example, combustion burners 21, 22, 23, 24, 25) mounted on the furnace wall. For example, the combustion burners 21, 22, 23, 24, 25 are arranged in a plurality of stages along the vertical direction as one set arranged at equal intervals along the circumferential direction of the fireplace 11. However, the shape of the fireplace 11, the number of combustion burners in one stage, and the number of stages are not limited to this embodiment.

Each combustion burner 21, 22, 23, 24, 25 is connected to a plurality of crushers (mills) 31, 32, 33, 34, 35 via pulverized coal supply pipes 26, 27, 28, 29, 30. There is. Although not shown, in the crushers 31, 32, 33, 34, 35, for example, a rotary table is rotatably supported in a housing, and a plurality of rollers are interlocked with the rotation of the rotary table above the rotary table. It is configured to be rotatably supported. When coal is thrown between a plurality of rollers and a rotary table, it is crushed to a predetermined size of pulverized coal and transported by a transport gas (primary air, oxidizing gas) to a classifier (not shown). The pulverized fuel classified within a predetermined size can be supplied to the combustion burners 21, 22, 23, 24, 25 from the pulverized coal supply pipes 26, 27, 28, 29, 30.

Further, the fireplace 11 is provided with a wind box 36 at a mounting position of each combustion burner 21, 22, 23, 24, 25. One end of the air duct 37 is connected to the air box 36. A forced ventilation fan (FDF: Forced Draft Fan) 38 is provided at the other end of the air duct 37.

The flue 13 is connected to the upper part of the fireplace 11 in the vertical direction. In the flue 13, primary superheater 43, secondary superheater 42, tertiary superheater 41, reheaters 44, 45, and coal saving devices 46, 47 are provided as heat exchangers for recovering the heat of the combustion gas. It is provided, and heat exchange is performed between the combustion gas generated by the combustion in the fireplace 11 and the water supply or steam flowing through each heat exchanger.

The flue 13 is connected to a gas duct 48 on the downstream side thereof, from which the combustion gas that has undergone heat exchange is discharged as exhaust gas. In the gas duct 48, an air heater (air preheater) 49 is provided between the gas duct 48 and the air duct 37, and heat exchange is performed between the air flowing through the air duct 37 and the exhaust gas flowing through the gas duct 48, and the combustion burners 21 and 22, The temperature of the combustion air supplied to 23, 24, and 25 can be raised.

Further, the flue 13 is provided with a denitration device 50 at a position upstream of the air heater 49. The denitration device 50 supplies a reducing agent having an action of reducing nitrogen oxides such as ammonia and urea water into the flue 13, and reacts the combustion gas to which the reducing agent is supplied with the nitrogen oxides and the reducing agent. Promote. As a result, nitrogen oxides in the combustion gas are removed or reduced. The gas duct 48 connected to the flue 13 is provided with a dust treatment device (electrostatic precipitator, desulfurization device) 51, an induction ventilator (IDF: Induced Draft Fan) 52, etc. at a position downstream of the air heater 49, and is downstream. A chimney 53 is provided at the end.

On the other hand, when a plurality of crushers 31, 32, 33, 34, 35 are driven, the generated pulverized fuel is passed through the pulverized coal supply pipes 26, 27, 28, 29, 30 together with the transport gas, and the combustion burners 21, 22, 23. , 24, 25 are supplied. Further, by exchanging heat with the exhaust gas discharged from the boiler 10 by the air heater 49, the heated combustion air (oxidizing gas) is sent from the air duct 37 through the air box 36 to each combustion burner 21, 22, 23, It is supplied to 24 and 25. Then, the combustion burners 21, 22, 23, 24, 25 blow the pulverized fuel mixture, which is a mixture of the pulverized fuel and the transport gas (primary air, oxidizing gas), into the fireplace 11 and the combustion air into the igniter 11. A flame can be formed by blowing in and igniting at this time. A flame is generated in the lower part of the furnace 11, and the combustion gas rises in the furnace 11 and is discharged to the flue 13.

Air is used as the oxidizing gas in this embodiment. The oxidizing gas may have a higher oxygen ratio than air or a lower oxygen ratio than air, and can be used by optimizing the flow rate of the fuel.

After that, the combustion gas is heat-exchanged by the primary superheater 43, the secondary superheater 42, the tertiary superheater 41, the reheaters 44, 45, and the economizers 46, 47 arranged in the flue 13, and then the denitration device. Nitrogen oxides are reduced and removed by 50 to form exhaust gas, and after the particulate matter is removed and the sulfur content is removed by the soot and dust treatment apparatus 51, the nitrogen oxides are discharged from the chimney 53 into the atmosphere.

The flue 13 is provided with a bypass flow path 55 that bypasses the economizers 46 and 47. A damper 56 is provided in the bypass flow path 55. The opening degree of the damper 56 is controlled by the boiler control device 100. Depending on the opening degree of the damper 56, a part of the combustion gas in the flue 13 bypasses the economizers 46 and 47 and heads for the denitration device 50. The boiler control device 100 controls not only the opening degree control of the damper 56 but also the fuel flow rate supplied to the boiler 10. For example, the boiler control device 100 controls the flow rate of coal supplied to a plurality of crushers 31, 32, 33, 34, 35 by a coal supply device (not shown), and the combustion burners 21, 22, 23, 24, The flow rate of the pulverized coal supplied to the 25 is controlled. The fuel flow rate control method is not limited to such an example.

Next, as one embodiment, the primary superheater 43, the secondary superheater 42, the tertiary superheater 41, the reheaters 44, 45, and the economizers 46, 47 provided in the flue 13 as heat exchangers. This will be described in detail. FIG. 2 is a schematic configuration diagram of the power plant 2 according to the embodiment. FIG. 2 schematically shows the heat exchanger of the boiler 10 and the steam system and the water supply system. In addition, FIG. 2 shows the position of each heat exchanger (primary superheater 43, secondary superheater 42, tertiary superheater 41, reheater 44, 45, economizer 46, 47) in the flue 13 accurately. It is not shown in.

As shown in FIG. 2, the power generation plant 2 is connected to the boiler system 1, the steam turbine 61 rotationally driven by the steam generated by the boiler system 1, and the steam turbine 61, and generates power according to the rotation of the steam turbine 61. A generator 3 for performing the above is provided. Further, the boiler system 1 further includes a heat medium circulation flow path L6 for circulating the heat medium. The heat medium circulation flow path L6 is provided with a heat receiving unit 81 for receiving the solar heat generated by the condensed sunlight and a circulation pump 82 for circulating the heat medium. The heat medium heated by the heat receiving unit 81 bypasses the water supply flowing into the flue 13 to the heat exchanger 83, and transfers heat to the water supply via the heat exchanger 83 to exchange heat. The boiler 10 generates steam by heating the supply water that has exchanged heat with the heat medium by burning fuel. That is, the boiler 10 uses the heat of the sun to generate steam.

The flue 13 is provided with a combustion gas passage 60 through which combustion gas passes, and the combustion gas passage 60 includes a tertiary superheater 41, a secondary superheater 42, a primary superheater 43, and a reheater 44. 45, economizers 46 and 47 are arranged. The tertiary superheater 41, the secondary superheater 42, and the primary superheater 43 may be provided in series via a header, but this header is omitted in FIG.

The steam turbine 61 operated by the steam generated by the boiler 10 is composed of, for example, a high-pressure turbine 62 and a low-pressure turbine 63. The steam turbine 61 may further include a medium-pressure turbine, and steam from the reheaters 44 and 45, which will be described later, may flow into the medium-pressure turbine and then into the low-pressure turbine 63. Here, the presence or absence of the medium-pressure turbine is referred to as the low-pressure turbine 63 for convenience.

A condenser 64 is connected to the low-pressure turbine 63, and the steam driving the low-pressure turbine 63 is cooled by the condenser 64 with cooling water (for example, seawater) to be condensed water. The condenser 64 is connected to the inlet header 65 of the first economizer 47 via the water supply line L1. The inlet header 65 is provided in the combustion gas passage 60. The water supply line L1 is provided with a water supply pump 66 outside the combustion gas passage 60, and after the water supply in the water supply line L1 is boosted by the water supply pump, the total amount of water supply is supplied by using the on-off valve 85 and the on-off valve 84. It can be bypassed and passed through the heat exchanger 83. The water supply heated by the heat exchanger 83 returns to the water supply line L1 again and is supplied to the inlet header 65. A water supply heater (not shown) may be provided upstream of the on-off valve 85 of the water supply line L1 to heat the water supply with the steam extracted from the steam turbine 61. .. The second economizer 46 is arranged above the first economizer 47, and an intermediate header 67 is provided between the economizers 46 and 47. The outlet header 68 is connected to the upper part of the second section economizer 46, and the outlet header 68 is arranged outside the combustion gas passage 60.

Here, a case where the boiler 10 is a drum type boiler that generates subcritical pressure steam will be described. In this case, the outlet header 68 is connected to the steam drum 69 (brackish water separator) arranged outside the combustion gas passage 60 via the water supply line L2. The steam drum 69 is connected to each heat transfer tube (not shown) of the furnace wall and is also connected to the primary superheater 43. The primary superheater 43, the secondary superheater 42, and the tertiary superheater 41 are connected to the high pressure turbine 62 via the steam line L3. The high-pressure turbine 62 is connected to the inlet header 70 of the first reheater 45 via the steam line L4. The inlet header 70 is provided in the combustion gas passage 60, and the first reheater 45 is connected to the second reheater 44 via the intermediate header 71. An outlet header 72 is connected to the upper part of the second reheater 44, and the intermediate header 71 and the outlet header 72 are arranged outside the combustion gas passage 60. Then, the outlet header 72 is connected to the low pressure turbine 63 via the steam line L5. The steam supplied from the outlet header 72 rotationally drives the low pressure turbine 63.

Therefore, when the combustion gas flows through the combustion gas passage 60 of the flue 13, the combustion gas is the tertiary superheater 41, the secondary superheater 42, the primary superheater 43, the reheaters 44, 45, the economizer 46, Heat is recovered in the order of 47. On the other hand, the water supplied from the water supply pump 66 is preheated by the economizers 47 and 46, then supplied to the steam drum 69, and is heated while being supplied to each heat transfer tube of the furnace wall (not shown) to be saturated steam. And returned to the steam drum 69.

The saturated steam of the steam drum 69 is introduced into the primary superheater 43, the secondary superheater 42, and the tertiary superheater 41, and is superheated by the combustion gas. The superheated steam generated by the primary superheater 43, the secondary superheater 42, and the tertiary superheater 41 is supplied to the high-pressure turbine 62 to rotationally drive the high-pressure turbine 62. The steam discharged from the high-pressure turbine 62 is introduced into the reheaters 45 and 44, overheated again, and then supplied to the low-pressure turbine 63 to rotationally drive the low-pressure turbine 63. A generator 3 is connected to the rotating shaft of the steam turbine 61 to generate electricity. The steam discharged from the low-pressure turbine 63 is cooled by the condenser 64 to be condensed, and is sent to the economizers 47 and 46 again.

Here, the case where the boiler 10 is a once-through boiler that produces subcritical pressure steam or supercritical pressure steam (not shown) will be described. The components common to the case of the drum type boiler described above will be described with the same reference numerals. In the once-through boiler, a furnace wall tube is provided between the economizer and the brackish water separator 69, and the furnace wall tube is composed of a plurality of heat transfer tubes provided so as to surround the furnace 11. When the water supplied from the water supply pump 66 passes through the furnace wall pipe via the economizers 46 and 47, it is heated by receiving radiation from the flame in the furnace 11. The water supply heated by passing through the furnace wall pipe is led to the brackish water separator 69. The steam separated by the brackish water separator 69 is supplied to the primary superheater 43, and the drain water separated by the brackish water separator 69 is guided to the condenser 64 via the drain water pipe.

The steam superheated by each superheater (primary superheater 43, secondary superheater 42, and tertiary superheater 41) by exchanging heat with the combustion gas is guided to the high pressure turbine 62 through the main steam pipe and has a high pressure. The turbine 62 is driven to rotate. The steam discharged from the high-pressure turbine 62 is introduced into the reheater, reheated, and then supplied to the low-pressure turbine 63 to rotationally drive the low-pressure turbine 63. A generator 3 is connected to the rotating shaft of the steam turbine 61 to generate electricity. The steam discharged from the low-pressure turbine 63 is cooled by the condenser 64 to be condensed, and is sent to the economizers 46 and 47 again.

(Arrangement of various sensors)
Hereinafter, arrangement of various sensors for performing measurements necessary for controlling the boiler control device 100 provided in the power generation system 2 will be described. At the position P1 shown in FIG. 1, a temperature sensor for measuring the outlet gas temperature of the air heater 49 is arranged. A thermocouple or the like can be used as the temperature sensor.

A line that bypasses the water supply to the heat exchanger 83 by closing the on-off valve 85 that bypasses the water supply to the heat exchanger 83 and opening the on-off valve 84 from the downstream side from the outlet of the water supply pump 66 shown in FIG. At position P2, a temperature sensor that measures the temperature of the water supply after heat exchange with the heat medium that receives the solar heat is arranged. At the position P3, a temperature sensor for measuring the temperature of the water supply before heat exchange with the heat medium that receives the solar heat is arranged. Further, a flow rate sensor for measuring the flow rate of the supplied water or a pressure sensor for measuring the pressure of the supplied water may be arranged at any of the positions P2 and P3. However, the flow rate and pressure of the water supply bypassed to the heat exchanger 83 may be measured at a place different from the positions P2 and P3 as long as the same measured value can be obtained. The pressure sensor may be omitted, or the flow rate sensor may be arranged only at one of the positions P2 and P3. Further, instead of the positions P2 and P3, for example, when the on-off valve 85 is used as a flow rate adjusting valve and only a part of the water supply is bypassed to the heat exchanger 83, the position after the bypass merges from the water supply line L1. The above sensor may be provided at P12 and at a position P13 before bypass branching from the water supply line L1 with the on-off valve 85 in between.

At the position P4, a temperature sensor for measuring the outlet water supply temperature of the economizer 46 is arranged. At the position P5, a temperature sensor for measuring the inlet steam temperature of the brackish water separator 69 is arranged. At position P6, a temperature sensor that measures the outlet steam temperature of the secondary superheater 42 is arranged.

(Configuration related to fuel flow control of boiler control device)
Hereinafter, a schematic configuration of the boiler control device 100 according to the embodiment will be described. FIG. 3 is a block diagram showing a configuration related to fuel flow rate control of the boiler control device 100 according to the embodiment.

The boiler control device 100 may be composed of an electric circuit or a computer. When the boiler control device 100 is composed of a computer, the boiler control device 100 includes a storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and a processor such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The processor realizes its function by executing a program stored in a storage device.

As shown in FIG. 3, the boiler control device 100 has an information acquisition unit 110 that acquires various information necessary for control, and a first control signal that acquires a first control signal of the fuel flow rate of the fuel supplied to the boiler 10. The acquisition unit 120, the heat reception amount information acquisition unit 130 configured to acquire heat reception amount information, and the fuel flow rate by correcting and controlling the fuel flow rate by obtaining heat transfer from the heat medium in which the water supply receives solar heat by the heat exchanger 83. The correction signal acquisition unit 140 configured to acquire the correction signal for the fuel flow, the fuel flow rate command unit 150 configured to output the fuel flow rate command for controlling the fuel flow rate, and the preceding fuel flow rate are controlled. A correction unit 160 for correcting a third control signal for the purpose is provided. As will be described later, the boiler control device 100 may further include an opening degree control unit 170 (see FIG. 7) that controls the opening degree of the damper 56.

Various information required for control includes information on the measured values of various sensors arranged in the power generation system 2 described above, information on the boiler load (ratio of the amount of generated steam to the rated steam amount of the boiler system 1), and generator output (power generation). Information about the power generated by the machine 3). The heat reception amount information is information on the heat reception amount received by the water supply by heat exchange with the heat medium that receives the solar heat. The correction signal is a signal for converting the heat reception amount indicated by the heat reception amount information acquired by the heat reception amount information acquisition unit 130 into the fuel flow rate and correcting the first control signal. Since this correction signal is used for the correction of the first control signal, it is distinguished from the correction of the third control signal by the correction unit 160.

The information acquisition unit 110 is necessary for calculating the generator output target command, the deviation of one or more steam temperatures, the boiler load (current boiler load) and the target boiler load, and the amount of heat received as various information necessary for control. Acquire sensor information (for example, measured values of water supply pressure, flow rate, temperature difference, etc.).

The deviation of one or more steam temperatures is, for example, the deviation between the set value and the measured value of the steam temperature at the outlet of the secondary superheater, and the deviation between the set value and the measured value of the steam temperature at the inlet of the steam separator. One of these deviations may be selected.

First, the deviation between the generator output target command acquired by the information acquisition unit 110 and one or more steam temperatures is input to the first control signal acquisition unit 120. The first control signal acquisition unit 120 generates a base fuel flow rate signal indicating the base fuel flow rate to be supplied to the boiler 10 based on the input generator output target command. Further, the first control signal acquisition unit 120 generates a second control signal based on the deviation of one or more input steam temperatures. The second control signal is a signal for correcting the base fuel flow rate signal based on the deviation of one or more steam temperatures.

The second control signal is generated so that, for example, about 10% to 20% of the base fuel is set as the maximum correction amount with respect to the base fuel according to the deviation of one or more steam temperatures. Factors that cause a deviation of one or more steam temperatures include, for example, a change in the calorific value of coal and a change in heat conduction efficiency due to the adhesion of ash to the heat transfer surface of the boiler. Normally, a deviation of one or more steam temperatures may occur due to fluctuations in the amount of heat received. However, in the boiler 10 according to the present embodiment, since the boiler control device 100 performs control based on the heat reception amount information, it is considered that the influence thereof is small. The first control signal acquisition unit 120 inputs the generated base fuel flow rate signal and the second control signal to the comparator 121 to acquire the deviation.

The information regarding the boiler load and the target boiler load acquired by the information acquisition unit 110 is input to the first control signal acquisition unit 120. The boiler load can be calculated, for example, from the values of measuring instruments such as pressure and temperature difference (not shown) of the steam line L3, and the values of the flow meter (not shown) of the water supply line L1.

The first control signal acquisition unit 120 inputs a signal relating to the boiler load to the function generator 124, inputs the boiler load change rate acquired from the signal relating to the boiler load to the function generator 125, and outputs the function generators 124 and 125. Is input to the multiplier 127 to obtain the multiplier value. The first control signal acquisition unit 120 acquires the load at the start of the load change from the signal related to the boiler load at the start of the boiler load change, and transfers the load at the start of the load change and the signal related to the target boiler load to the comparator 123. Enter to get the boiler load change width. The first control signal acquisition unit 120 inputs the boiler load change width to the function generator 126. The output signal of the function generator 126 and the output signal of the multiplier 127 are input to the multiplier 128. The output signal of the multiplier 128 is acquired as a third control signal according to the boiler load condition.

The third control signal is a signal for improving the responsiveness (quick response) of the fuel flow rate control by temporarily changing the fuel flow rate with respect to the boiler load from the base fuel flow rate and outputting it. Used for flow control. Therefore, this signal may temporarily output a fuel flow rate command indicating a fuel flow rate that exceeds the maximum value of the base fuel flow rate in steady fuel flow rate control.

The information regarding the boiler load and the target boiler load acquired by the information acquisition unit 110 is input to the correction unit 160 of the first control signal acquisition unit 120. The correction unit 160 inputs a signal related to the boiler load to the function generator 164, inputs the boiler load change rate acquired from the signal related to the boiler load to the function generator 165, and inputs the outputs of the function generators 164 and 165 to the multiplier 167. Enter in to get the multiplier value. The correction unit 160 inputs a signal relating to the boiler load at the start of the boiler load change and a signal relating to the target boiler load to the comparator 163, acquires a deviation, and inputs the deviation to the function generator 166. The output signal of the function generator 166 and the output signal of the multiplier 167 are input to the multiplier 168.

Here, the function generators 164, 165, and 166 of the correction unit 160 are different functions from the function generators 124, 125, and 126 for acquiring the third control signal. The signal input to the multiplier 168 is a signal for correcting the third control signal for controlling the preceding fuel flow rate to improve the responsiveness (quick response) of the fuel flow rate control, and is the preceding fuel flow rate correction control. Used for.

The sensor information necessary for calculating the heat reception amount acquired by the information acquisition unit 110 is input to the heat reception amount information acquisition unit 130. The heat receiving amount information acquisition unit 130 calculates the heat receiving amount based on the sensor information.

Specifically, the heat receiving amount information acquisition unit 130 receives a temperature difference of water supply at a front-rear position (front-rear position of the heat exchanger 83) that exchanges heat with a heat medium that receives solar heat (water supply at position P2 in the example shown in FIG. 2). The temperature difference between the temperature and the water supply temperature at the position P3) is acquired, and the amount of heat received is calculated based on the temperature difference, the flow rate of the water supply water acquired from the flow sensor, and the specific heat obtained from the pressure of the water supply. For example, the heat receiving amount information acquisition unit 130 acquires the temperature difference of the water supply temperature from the measured values of the temperature sensors provided at the positions P2 and P3, multiplies it by the specific heat of the water supply, and calculates the value as the specific enthalpy. Calculated as the amount of change. Further, the heat receiving amount information acquisition unit 130 multiplies the value by the flow rate of the supply water acquired from the flow rate sensor, and calculates the value as the heat receiving amount.

Since the flow rate and pressure of the water supply usually hardly change at the front-rear position (the front-rear position of the heat exchanger 83) where heat is exchanged with the heat medium, it may be regarded as constant and measured by one flow rate sensor. However, when the on-off valve 85 is used as a flow control valve so that the flow rate of the supply water bypassed from the water supply line L1 to the heat exchanger 83 is a part of the water supply line L1, the flow is bypassed to the heat exchanger 83. The flow rate is acquired from the flow rate sensor, the multiplication value of the specific enthalpy and the flow rate is obtained from the temperature sensor and the flow rate sensor at the positions P3 and P2 before and after the bypassed heat exchanger 83, and the difference between them is obtained from the heat exchanger 83. It may be calculated as the amount of heat received by the water supply. A position P13 is provided from the water supply line L1 before the bypass branch, and a position P12 is provided after the bypass merges from the water supply line L1 with the on-off valve 85 in between. The multiplication value may be obtained, and the difference between them may be calculated as the amount of heat received by the heat exchanger 83.

As a modification of this embodiment, in order to improve the heat receiving efficiency of solar heat, it may be necessary to control the circulation flow rate of the heat medium in the heat medium circulation flow path L6. At this time, when the solar heat receiving information is acquired, if the flow rate of the heat medium changes at the front and rear positions of the heat receiving unit 81, the flow rates at the front and rear positions are acquired from the flow rate sensor, and the front and rear of the heat receiving unit 81 The multiplication value of the specific enthalpy and the flow rate is obtained from the temperature sensor and the flow rate sensor for each position, the difference between them is calculated as the amount of solar heat received by the heat receiving unit 81, and the circulating flow rate of the heat medium in the heat medium circulation flow path L6. May be controlled. In addition, the amount of solar heat received may be calculated in consideration of the change in pressure. For example, the heat receiving amount information acquisition unit 130 acquires the measured values of the pressure of the water supply at the front and rear positions where heat is exchanged with the heat medium from the pressure sensors, and takes these measured values into consideration to obtain each of the specific enthalpies at the front and rear positions. It may be configured to calculate and more accurately calculate the specific enthalpy difference. Further, for example, when the heat medium undergoes a phase change, it is necessary to evaluate the amount of heat absorbed by the latent heat, and the heat receiving amount information acquisition unit 130 measures the pressure of the heat medium at the front and rear positions of the heat receiving unit 81 that receives solar heat. Each value is acquired from the pressure sensor, each of the enthalpies at the front and rear positions is calculated by adding those measured values, the enthalpy difference is calculated more accurately, and the circulation flow rate of the heat medium in the heat medium circulation flow path L6. May be configured to control.

The heat receiving amount information indicating the heat receiving amount calculated by the heat receiving amount information acquisition unit 130 is input to the correction unit 160. The correction unit 160 calculates the amount of heat reception increase at the monitoring part (heat exchanger 83) from the heat reception amount information, and converts it into the fuel flow rate. The correction unit 160 inputs to the multiplier 169 a signal indicating the result of converting the heat receiving increase amount into the fuel flow rate and an output signal of the multiplier 168. The output signal of the multiplier 169 is input to the comparator 129 together with the output signal of the multiplier 128 which is the third control signal. This makes it possible to use the third control signal for the preceding fuel flow rate correction control for correcting the third control signal by the correction unit 160.

Here, the correction conditions of the correction unit 160 will be described. When the measured value of the boiler load at the start of the boiler load change, the rate of change of the boiler load, and the change width of the boiler load satisfy the predetermined conditions, the correction unit 160 precedes the fuel when the predetermined conditions are not satisfied. The third control signal is corrected by the preceding fuel flow rate correction control by the correction unit 160 so as to reduce the fuel flow rate by the third control signal commanded as the flow rate. Predetermined conditions are, for example, various boiler loads in which the margin for the allowable upper limit temperature as a specification such as the material and structure of the heat exchanger at least one of the furnace outlet steam temperature and the primary superheater outlet steam temperature is equal to or less than the standard value. It is a condition of the value (value of boiler load, change rate of boiler load, change width of boiler load, etc.).

As a configuration for determining whether or not a predetermined condition is satisfied, for example, the function generators 164, 165, and 166 of the correction unit 160 have a heat exchanger whose steam temperature or water supply temperature changes, for example, when the boiler load increases. A signal to reduce the fuel flow rate is output from the multiplier 169 only when the margin with respect to the allowable upper limit temperature as the specification is less than the reference value and the boiler load change rate and the boiler load change width are larger than the predetermined values. The function is set. That is, when the predetermined condition is not satisfied, the function is set so that the amount of decrease due to the preceding fuel flow rate correction control to the fuel flow rate commanded as the preceding fuel flow rate by the correction of the correction unit 160 becomes zero.

Further, the correction unit 160 determines the amount of decrease in the fuel flow rate in the correction by the preceding fuel flow rate correction control to the fuel flow rate commanded as the preceding fuel flow rate of the third control signal based on the heat receiving amount indicated by the heat receiving amount information. It is composed of. For example, the correction unit 160 is a value obtained by multiplying the amount of heat received indicated by the amount of heat received information by a coefficient (for example, a coefficient set in advance by simulation or an actual machine test, and one example thereof is the monitoring part (heat exchanger 83). It may be configured to convert (such as 0.6 times the amount of increase in heat reception) into the fuel flow rate and determine it as the amount of decrease in the fuel flow rate.

The first control signal acquisition unit 120 inputs the output signal of the comparator 121 and the output signal of the adder 129 to the adder 122, and acquires the output signal of the adder 122 as the first control signal. The heat receiving amount information indicating the heat receiving amount calculated by the heat receiving amount information acquisition unit 130 is input not only to the correction unit 160 but also to the correction signal acquisition unit 140. The calculation of inputting the output signal of the multiplier 168, which is the preceding fuel flow rate correction control signal, and the output signal of the multiplier 128, which is the third control signal, to the comparator 129 is an calculation in the first control signal acquisition unit 120. The output signal of the multiplier 122 may be used as the first control signal by performing the calculation in the correction signal acquisition unit 140 and inputting the signal to the multiplier 122.

The correction signal acquisition unit 140 converts the heat reception amount indicated by the input heat reception amount information into the fuel flow rate, and acquires the correction signal for correcting the first control signal and the delay element thereof based on the conversion result. The correction signal acquisition unit 140 outputs a signal in which a delay element is added to the correction signal, and holds the time corresponding to the delay element without correcting the current fuel flow rate.

The delay element is, for example, a primary delay element having a time constant until the outlet water supply temperature of the economizers 46 and 47 changes depending on the amount of heat held by the economizers 46 and 47 with respect to the change in the heat reception amount of the heat receiving unit 81. The start of correction of the preceding fuel flow rate with respect to the change in the heat receiving amount of the unit 81 is delayed, and the time until the change in the heat receiving amount with respect to the boiler load settles down is taken into consideration. In this case, the time constant of the change in the outlet water supply temperature of the economizers 46 and 47 is set to, for example, 0 to 600 seconds. The time constant corresponding to the delay element is set in advance by, for example, a simulation or an actual machine test, and may be set to 0 seconds for a boiler load change that does not require the delay element, for example. The delay element is not limited to such a primary delay element, and may be an element that adds a waste time (delay time) to the correction signal, or may be a secondary delay element.

The output signal of the correction signal acquisition unit 140 (correction signal to which a delay element is added) and the output signal of the adder 122 (first control signal) are input to the comparator 145. The output signal of the comparator 145 is input to the fuel flow rate command unit 150. That is, the fuel flow rate command unit 150 outputs the fuel flow rate command based on the first control signal and the correction signal to which the delay element is added.

(Significance of fuel flow control of boiler control device)
Hereinafter, the significance of fuel flow rate control by the boiler control device 100 described above will be described. Here, the boiler control device according to the comparative example will be described. However, the detailed configuration is omitted. The boiler according to the comparative example includes a heat exchanger that exchanges heat from a heat medium that receives solar heat to a bypassed water supply, an economizer, a fireplace, and a primary superheater, a secondary superheater, and a tertiary superheater. Be prepared. When the main steam temperature exceeds the reference value high temperature, the boiler control device according to the comparative example saves from the heat exchanger so that the water supply temperature or the steam temperature does not reach the allowable upper limit temperature as the specifications of the heat exchanger. A part of the water supply to the economizer is branched and supplied to the primary superheater outlet and the secondary superheater outlet. Such a bypass supply of water supply acts as spray water and lowers the steam temperature at the primary superheater outlet and the secondary superheater outlet.

FIG. 4 is a conceptual diagram for explaining the temperature distribution in the boiler according to the comparative example. This figure shows the temperature distribution of the water supply temperature or steam temperature that changes from the upstream side to the downstream side. In the example shown in FIG. 4, as described above, the primary superheater outlet temperature and the secondary superheater outlet temperature are lowered by the bypass supply of the supply water acting as spray water. In this figure, regarding the temperature distribution of water supply temperature or steam temperature, there is a case where there is a heat receiving amount (heat receiving amount by heat exchange with a heat medium that receives heat from solar heat) and a heat receiving amount from solar heat shown by a solid line. It is shown in a graph format that can be distinguished from the case without. Comparing both of these, it can be seen that even if the amount of heat received fluctuates, the fluctuation of the steam temperature at the outlet of the secondary superheater on the downstream side is suppressed. This is because the spray water is controlled based on the main steam temperature. However, in the boiler according to the comparative example, focusing on the economizer outlet temperature, the fireplace outlet temperature, and the primary superheater outlet temperature, it can be seen that these temperatures increase as the amount of heat received increases. Therefore, these temperatures may reach the allowable upper limit temperature as a heat exchanger.

On the other hand, in the boiler control device 100 described above, the amount of decrease in the fuel flow rate is given to the third control signal commanded as the preceding fuel flow rate obtained by the multiplier 128 and the fuel flow rate command obtained by the correction unit 160 and the multiplier 128. The preceding fuel flow rate correction signal is calculated by the multiplier 122, and the correction signal corresponding to the heat reception amount obtained by the heat reception amount information acquisition unit 130 is calculated by the comparator 145, whereby the fuel flow rate command is output and the fuel is fueled. Control the flow rate appropriately. Therefore, the temperature on the upstream side of the primary superheater outlet temperature is also controlled. Therefore, the temperature distribution in the boiler 10 (for example, the temperature distribution from the inlet of the economizers 46 and 47 to the outlet of the primary superheater 43) can be more optimized with respect to the fluctuation of the heat receiving amount, and these temperatures can be optimized. It is possible to prevent the distribution from reaching the allowable upper limit temperature as a specification of the heat exchanger. Further, when the amount of heat received changes a lot, the fuel flow rate is more appropriately reduced from the preceding fuel flow rate supplied to the boiler 10, so that the fuel consumption of the boiler can be reduced.

FIG. 5 is a diagram for explaining correction by the correction unit 160 with respect to the third control signal used for the preceding fuel flow rate control according to the load condition of the boiler control device 100 according to the embodiment. It is a conceptual diagram which shows the temporal transition of the steam temperature of 10 (the outlet temperature of the primary superheater 43). First, there is a case where the boiler load is suddenly increased so as to maintain the generator output in response to a sudden decrease in the amount of heat received, or a sudden change in the output requirement of the generator 3 (a sudden increase in the target boiler load) occurs. In this case, in order to improve the responsiveness (quick response) of the fuel flow rate control to the increase in the boiler load, the preceding fuel flow rate control in which the fuel flow rate to be supplied to the boiler 10 is input in advance is implemented.

Here, as shown in FIG. 5, when the third control signal is not corrected, and as shown by the solid line, when the boiler load is rapidly increased, the steam temperature at the outlet of the primary superheater 43 of the boiler 10 is increased. It has been found that the maximum allowable temperature may be approached as the specifications of the heat exchanger and the maximum allowable temperature may be reached. On the other hand, according to the boiler control device 100, when predetermined conditions (various conditions such as a boiler load value, a boiler load change rate, and a boiler load change width) are satisfied, the third control signal is used for advance input. The correction is performed by the preceding fuel flow rate correction control by the correction unit 160 so that the fuel flow rate is reduced. As a result, when the amount of heat received suddenly decreases, the boiler load suddenly increases, or when the generator 3 suddenly changes the output requirement (the target boiler load suddenly increases), the boiler load increases sharply. Even in this case, as shown by the broken line, the margin of the steam temperature with respect to the allowable upper limit temperature as the specification of the heat exchanger is increased as compared with the case where there is no correction by the correction unit 160 of the third control signal shown by the solid line. be able to.

FIG. 6 is a diagram for explaining the correction of the third control signal of the boiler control device 100 according to the embodiment, and is a conceptual diagram showing the temporal transition of the fuel flow rate of the boiler 10. This figure shows the fuel flow rate when the boiler load suddenly increases when the amount of solar heat received drops sharply, or when the output requirement of the generator 3 suddenly changes (target boiler load suddenly increases). Shows the transition of. The solid line is the base fuel flow rate according to the target boiler load. On the other hand, in order to improve the responsiveness (quick response) of the fuel flow rate control when the boiler load is increased, a fuel flow rate larger than the base fuel flow rate is input in advance by the third control signal, but the boiler load situation If there is no correction after adding the corresponding fuel flow rate, it will take longer to input with a fuel flow rate larger than the base fuel flow rate as shown by the one-point chain line, and after temporarily overshooting, it will be the set value of the base fuel flow rate. Calm down.

However, if the fuel flow rate of the overshooting portion of the fuel flow rate is large, for example, the steam temperature at the outlet of the primary superheater 43 approaches the allowable upper limit temperature as the heat exchanger specification as described above, and the allowable upper limit temperature. May be unfavorable from the viewpoint of optimizing the temperature distribution in the boiler 10. In this regard, according to the boiler control device 100, when predetermined conditions (various conditions such as a boiler load value, a boiler load change rate, and a boiler load change width) are satisfied, the third control signal is corrected. The fuel flow rate of the fuel flow rate command is corrected so as to decrease by the preceding fuel correction control by the unit 160. As a result, as shown by the broken line in the figure, the preceding fuel flow rate of the overshooting portion is reduced. As a result, the fuel consumption can be appropriately reduced from the preceding fuel flow rate supplied to the boiler 10. In particular, the greater the change in the amount of heat received by the heat exchanger 83 from the heat medium received from the solar heat to the bypassed water, the more appropriately the amount of reduction in fuel consumption is adjusted from the preceding fuel flow rate. The amount of reduction in the amount of fuel supplied to the boiler 10 can be increased.

(Configuration related to damper opening control of boiler control device)
Hereinafter, a configuration relating to opening degree control of the damper 56 of the boiler control device 100 will be described. FIG. 7 is a block diagram showing a configuration related to opening degree control of the damper 56 of the boiler control device 100 according to the embodiment.

As shown in FIG. 7, the boiler control device 100 includes an information acquisition unit 110 and an opening degree control unit 170 that controls the opening degree of the damper 56. In order to improve the responsiveness (quick response) of the fuel flow rate control when increasing the boiler load, the fuel flow rate command is commanded as the preceding fuel flow rate by the preceding fuel correction control by the correction unit 160 from the above-mentioned third control signal. Correct so that the fuel flow rate decreases. This correction has the effect of lowering the steam temperature at the outlet of the primary superheater 43 from the allowable upper limit temperature as a specification of the heat exchanger. However, when this effect is insufficient and the decrease in the steam temperature at the outlet of the primary superheater 43 is insufficient, the opening degree control unit 170 controls the opening degree of the damper 56. The opening degree control of the damper 56 may be controlled by the opening degree control unit 170 without using the preceding fuel correction control by the correction unit 160.

The information acquisition unit 110 acquires various information necessary for controlling the opening degree of the damper 56. Various information necessary for controlling the opening degree of the damper 56 includes, for example, information on the outlet water supply temperature of the economizers 46 and 47, the deviation of the outlet gas temperature of the air heater 49 from the target temperature, and the denitration device acquired from each temperature sensor. Includes information and the like indicating the deviation of the inlet gas temperature of 50 from the target temperature. The expression of the outlet water supply temperature of the economizers 46 and 47 means the outlet water supply temperature of the economizer 47. That is, in the boiler 10 provided with only one economizer, the opening degree of the damper 56 may be controlled by using the outlet water supply temperature of the economizer, and a plurality of economizers (for example, the economizers 46 and 47) may be controlled. In the boiler 10 provided with)), the opening degree of the damper 56 may be controlled based on the outlet water supply temperature of the economizer (for example, the economizer 47) which tends to be particularly high in temperature.

First, the information regarding the outlet water supply temperature of the economizers 46 and 47 acquired by the information acquisition unit 110 is input to the comparators 171 and 172 of the opening degree control unit 170. The comparator 171 compares the first set temperature with the outlet water supply temperatures of the economizers 46 and 47 and outputs a deviation. The first set temperature is set to a value 5 ° C. to 10 ° C. lower than the saturated steam temperature of the outlet water supply temperature of the economizers 46 and 47, for example, to achieve steaming in the economizers 46 and 47. Suppress.

The output signal of the comparator 171 is input to the PI control unit 173. The PI control unit 173 performs proportional integration control (PI control) based on the output signal of the comparator 171 and the feedback signal of the opening degree of the damper 56. Further, as the margin of the outlet water supply temperature of the economizers 46 and 47 with respect to the saturated steam temperature, a value 10 ° C. lower than the saturated steam temperature is set as an example, and the PI control unit 173 sets a temperature difference of 10 ° C. or more as a tracking condition. It is tracked and determines whether or not PI control of the opening degree of the damper 56 needs to be performed. From the specifications as a heat exchanger in the economizers 46 and 47, it is preferable to prevent the water supply from being vaporized due to steaming. Therefore, it goes without saying that the margin is the difference between the outlet water supply temperature and the saturated steam temperature so that the outlet water supply temperatures of the economizers 46 and 47 do not exceed the saturated steam temperature.

The switching unit 175 performs switching depending on whether or not the margin is 10 ° C. or higher. The switching unit 175 outputs the result of inputting the economizer outlet damper opening to the function generator 176 when the margin is 10 ° C. or higher, but when the margin is less than 10 ° C. , The output signal of the PI control unit 173 is output to control the opening degree of the damper 56 so that the margin does not fall below 10 ° C. The economizer outlet damper (not shown) is different from the damper 56 for bypassing the economizers 46 and 47, and is installed downstream of the economizers 46 and 47 to distribute the flow rate with the bypass flow path 55. It is used for differential pressure adjustment (because the pressure loss coefficient of the bypass flow path and the main flow path are different). As described above, if the temperature margin is sufficient, the damper 56 is set to the program opening degree with respect to the opening degree of the economizer outlet damper.

The comparator 172 compares the second set temperature with the outlet water supply temperatures of the economizers 46 and 47 and outputs a deviation. The second set temperature is set to a value 15 ° C. lower than the saturated steam temperature of the economizers 46 and 47, for example. That is, the second set temperature is set to a temperature lower than the first set temperature. This is because, as will be described later, when the rate of decrease in margin (rate of decrease in margin) is large and there is a high possibility that the saturated steam temperature will be reached, the margin is increased to ensure that the economizers 46 and 47 are used. This is to suppress teaming.

Further, when the opening degree of the damper 56 is controlled by using the outlet water supply temperature of the economizers 46 and 47, the combustion gas temperature in the flue 13 and the gas duct 48 of the boiler system 1 is higher than that of the economizers 46 and 47. Since there is a risk of reaching the specified temperature in the equipment on the downstream side, it is preferable to set the opening degree of the damper 56 to the minimum opening degree so as not to open it more than necessary. The denitration device 50, the air heater 49, and the like may reach the specified temperature in the equipment on the downstream side.

Therefore, at least one of the outlet gas temperature of the air heater 49 and the inlet gas temperature of the denitration device 50 is monitored. FIG. 7 shows, as an example, a case where both the outlet gas temperature of the air heater 49 and the inlet gas temperature of the denitration device 50 are monitored. Since there is a difference of more than double the temperature change width between the outlet gas temperature of the air heater 49 and the inlet gas temperature of the denitration device 50 when the damper opening is raised, the deviation of the denitration device 50 is required to make each gas temperature deviation equal. Needs to be doubled. Therefore, the switcher 179 selects the larger value of the temperature deviation of the outlet gas of the air heater 49 and the deviation of the temperature deviation of the inlet gas of the denitration device 50, whichever is larger, and inputs it to the AND circuit.

The output signal of the comparator 172 is input to the P control unit 174 that performs proportional control. The output signal of the P control unit 174 is input to the switching unit 177. The switching unit 177 determines whether the temperature deviation selected by the switch 179, the rate of decrease in margin (decrease rate of margin) is equal to or higher than the reference value, and whether the margin is equal to or lower than the reference value (for example, 15 ° C). Switching is performed based on the AND condition of whether or not. For example, when the margin is 15 ° C. or lower, the rate of decrease of the margin is equal to or higher than the reference value, and the temperature deviation is equal to or higher than the reference value, the switching unit 177 is a P control unit as a correction amount for the opening degree of the damper 56. The output signal of 174 is output. On the other hand, if this is not the case, the switching unit 177 outputs zero by initializing the correction amount of the damper opening degree at 0%.

The output signals of the switching units 175 and 177 are input to the adder 178, and the addition result thereof is output as the minimum opening degree of the damper 56. That is, when the water supply outlet temperature of the economizers 46 and 47 is likely to reach the saturated steam temperature, the minimum opening degree of the damper 56 is controlled to be large. If this is not the case, the opening degree of the damper 56 is controlled at the minimum opening degree for adjusting the temperature of the denitration device 50 and the air heater 49.

The opening degree control unit 170 determines the difference between the outlet water supply temperature and the saturated steam temperature of the economizers 46 and 47 and the reduction rate of the difference between the outlet water supply temperature and the saturated steam temperature of the economizers 46 and 47. Based on this, the opening degree of the damper 56 may be controlled. Further, the opening degree control unit 170 may control the opening degree of the damper 56 to be the minimum opening degree based on the outlet gas temperature of the air heater 49 or the inlet gas temperature of the denitration device 50.

For example, in the opening degree control unit 170, the difference between the outlet water supply temperature of the economizers 46 and 47 and the saturated steam temperature is equal to or less than the reference value, and the outlet water supply temperature and the saturated steam temperature of the economizers 46 and 47 are set. The opening degree of the damper 56 is opened when any one of the conditions that the reduction rate of the difference is equal to or higher than the reference value and the outlet gas temperature of the air heater 49 or the inlet gas temperature of the denitration device 50 is equal to or higher than the reference value is satisfied. May be increased to suppress steaming of the economizers 46 and 47, and the opening degree of the damper 56 may be controlled to be the minimum opening without opening more than necessary. When controlling the opening degree of the damper 56 so as to be lower than the specified temperature of the denitration device 50 and the air heater 49 in consideration of the outlet temperature of the air heater 49, the reaction temperature of the denitration device 50 should be secured and the corrosion of the air heater 49 should be suppressed. Can be done.

(Significance of damper opening control of boiler control device)
Hereinafter, the significance of the damper opening degree control by the boiler control device 100 described above when reducing the boiler load of the boiler 10 will be described. FIG. 8 is a diagram for explaining the opening degree control of the damper of the boiler control device 100 according to the embodiment, such as a sudden decrease in the boiler load when the amount of heat received from solar heat suddenly increases, and the generator 3 When the boiler load is suddenly reduced due to a sudden change in the output requirement (target boiler load sudden decrease), the outlet water supply temperature of the economizers 46 and 47 due to the decrease in the boiler load It is a conceptual diagram which shows the time transition.

As shown in FIG. 8, when the boiler load of the boiler 10 decreases, the water supply pressure decreases, so that the saturated steam temperature shown by the broken line also decreases. When the boiler load decreases from the state where the outlet water supply temperature of the economizers 46 and 47 is high due to the operation with a high boiler load such as rated operation depending on the amount of heat received, the heat possessed by the economizers 46 and 47 reduces the temperature. The decrease in water supply temperature is slower, and the rate of decrease in saturated steam temperature is faster. Therefore, when the opening degree control of the damper 56 described above is not performed, the outlet water supply temperature of the economizers 46 and 47 decreases with a time delay as shown by the solid line. Therefore, the margin of the outlet water supply temperature of the economizers 46 and 47 with respect to the saturated steam temperature becomes small, and there is a possibility that steam is generated at or inside the outlets of the economizers 46 and 47.

On the other hand, when the opening degree of the damper 56 is controlled as shown by the dotted line, the opening degree of the damper 56 is increased, and a part of the high temperature gas flowing into the economizers 46 and 47 is branched and reduced. Since the economizers 46 and 47 are guided to bypass, the water supply temperature of the economizers 46 and 47 drops rapidly. As a result, the margin of the outlet water supply temperature of the economizers 46 and 47 with respect to the saturated steam temperature increases.

On the other hand, when reducing the boiler load, the responsiveness (quick response) of the fuel flow rate control is improved by the above-mentioned third control signal, and the fuel flow rate is appropriately corrected to the fuel flow rate command commanded as the preceding fuel flow rate. However, it takes time to lower the outlet water supply temperature of the coal saving devices 46 and 47 by reducing the fuel flow rate to the boiler 10. On the other hand, the opening degree control of the damper 56 directly lowers the outlet water supply temperature of the economizers 46 and 47, so that high responsiveness and high temperature reduction effect can be obtained. Therefore, when reducing the boiler load, the opening degree control of the damper 56 may be prioritized to suppress steaming at the outlets of the economizers 46 and 47.

(Flow of control processing)
Hereinafter, a specific example of the control process executed by the boiler control device 100 will be described. Here, the process related to the fuel flow rate control will be described, but the control process may be transformed into a process that combines the process of controlling the opening degree of the damper 56. FIG. 9 is a flowchart showing an example of the control process executed by the boiler control device 100 according to the embodiment.

As shown in FIG. 9, the boiler control device 100 acquires the base fuel flow rate signal based on the generator output target command (step S1). The boiler control device 100 acquires a second control signal based on one or more steam temperature deviations (step S2). The boiler control device 100 acquires a third control signal for controlling the preceding fuel flow rate based on the boiler load condition (step S3). Here, the boiler control device 100 determines whether or not the predetermined conditions (boiler load value, boiler load change rate, boiler load change width, etc.) are satisfied (step S4). For this determination, for example, in the function generators 164, 165, 166 shown in FIG. 3, the function is set so that the correction amount is zero when the predetermined condition is not satisfied, and the correction amount is not zero when the predetermined condition is satisfied. It may be realized by being performed, or it may be realized by arithmetic processing by software.

Here, when it is determined that the predetermined condition is satisfied (step S4; Yes), the boiler control device 100 corrects the third control signal by the preceding fuel flow rate correction control (step S5). On the other hand, when it is determined that the predetermined condition is not satisfied (step S4; No), the boiler control device 100 skips the process of step S5.

Next, the boiler control device 100 acquires the first control signal based on the base fuel flow rate signal, the second control signal, and the third control signal (correction has been determined by the preceding fuel flow rate correction control) (step S6). ). The boiler control device 100 acquires heat reception amount information indicating the heat transfer amount to the water supply (step S7). The boiler control device 100 converts the amount of heat received indicated by the amount of heat received information into the fuel flow rate and acquires a correction signal (step S8). The boiler control device 100 outputs a fuel flow rate command based on the first control signal and the correction signal to which the delay element is added (step S9).

The present disclosure is not limited to the above-described embodiment, and includes a modification of the above-described embodiment and a combination of these embodiments as appropriate.

(Modification example)
For example, the order of each of the control processes executed by the boiler control device 100 is not limited to the example shown in FIG. 9, and can be changed as appropriate. In addition, some processing may be omitted.

The boiler control device 100 according to some of the above-described embodiments may be configured to realize all or part of the above processing by software. In this case, the boiler control device 100 is a computer-readable recording medium in which a processor such as a CPU or GPU, a storage device such as a RAM or a ROM, and a program for realizing all or a part of the above processing are recorded. Be prepared.

Then, the processor reads the program recorded in the storage medium and executes information processing and arithmetic processing to realize the same processing as the boiler control device 100 described above. Computer-readable recording media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like. Further, such a program may be distributed to a computer via a communication line, and the distributed computer may execute the program.

In the above-described embodiment, as an example of receiving heat fluctuating from the outside, solar heat generated by condensed sunlight is used, but the present invention is not limited to this. The heat that fluctuates from the outside includes factory exhaust heat, combustion heat and exhaust heat of by-product gas that fluctuates fuel composition and fuel amount, and combustion heat and exhaust heat of biomass fuel that fluctuates fuel composition and fuel amount. Can be used.

Further, in the above-described embodiment, the boiler is a coal-fired boiler 10, but the solid fuel is a boiler that uses biomass fuel, PC (Petroleum Coke) fuel generated during petroleum refining, petroleum residue, or the like. You may. Further, the fuel is not limited to solid fuel, and the boiler may be a boiler that uses liquid fuel such as heavy oil. Furthermore, gaseous fuel (by-product gas, etc.) can also be used as the fuel. And the boiler can also be applied to the co-firing of these fuels.

(Summary)
The contents described in each of the above embodiments are grasped as follows, for example.

(1) The boiler control device (100) according to the embodiment of the present disclosure is
A boiler control device (100) that generates steam from water supply.
The first control signal for acquiring the first control signal generated based on the base fuel flow rate signal generated based on the output target command and the third control signal according to the boiler load condition for the fuel flow rate of the fuel supplied to the boiler. Acquisition department (120) and
A heat receiving amount information acquisition unit (130) configured to acquire heat receiving amount information regarding the heat receiving amount of fluctuating heat from the outside, and
A correction signal configured to convert the heat reception amount indicated by the heat reception amount information acquired by the heat reception amount information acquisition unit (130) into the fuel flow rate and acquire a correction signal for correcting the first control signal. Acquisition department (140) and
A fuel flow rate command unit (150) configured to output a fuel flow rate command for controlling the fuel flow rate based on the first control signal and the correction signal to which a delay element is added.
To be equipped.

According to the configuration described in (1) above, the first control signal generated based on the output target command and the boiler load condition is corrected by converting the amount of heat received from the fluctuating heat from the outside into the fuel flow rate. A fuel flow rate command for correcting the fuel flow rate by a signal is output. Therefore, it is possible to control the fuel flow rate more appropriately with respect to fluctuations in the amount of heat received from fluctuating heat from the outside. This makes it possible to control the boiler (10) so as to satisfy the operating conditions, and also to supply fuel to the boiler (10) according to the amount of heat received from externally fluctuating heat such as solar heat. The flow rate can be reduced to reduce fuel consumption. Further, the temperature distribution in the boiler (10) (for example, the temperature distribution from the inlet of the economizer (46,47) to the outlet of the primary superheater (43)) with respect to the fluctuation of the amount of heat received by correcting the first control signal. ) Can be more optimized.

In addition, as a result of diligent studies by the inventor of the present application, it has been found that when the fuel flow rate is immediately controlled in response to a change in the amount of heat received, appropriate control cannot be performed. There is a time lag between the timing at which the amount of heat received changes and the timing at which the temperature distribution in the boiler (10) changes due to the change. This is due to, for example, the heat possessed by the heat exchanger provided in the boiler (10). Under such conditions, when the fuel flow rate is controlled according to the timing when the heat receiving amount changes, it is considered that the control timing is too early and appropriate control cannot be performed.

In this regard, according to the configuration described in (1) above, since a delay element is added to the correction signal, it is possible to adjust the timing of controlling the fuel flow rate with respect to the amount of heat received, and therefore an appropriate fuel flow rate. Can be controlled.

(2) In some embodiments, in the configuration described in (1) above,
The delay element is a primary delay element having a time constant of change in the outlet water supply temperature of the economizer (46, 47) with respect to the change in the amount of heat received.

According to the configuration described in (2) above, it is possible to reduce the possibility that the outlet water supply temperature of the economizer (46, 47) deviates from the allowable range as the specifications of the heat exchanger. In addition, by further optimizing the outlet water supply temperature of the economizers (46, 47), the temperature at a position further downstream (for example, the outlet steam temperature in the primary superheater (43)) is also optionally optimized. be able to.

(3) In some embodiments, in the configuration described in (1) or (2) above,
The first control signal acquisition unit (120) further generates the first control signal based on the second control signal generated based on the deviation of one or more steam temperatures from the base fuel flow rate signal.

According to the configuration described in (3) above, the first control signal is generated based on the deviation of one or more steam temperatures, and the fuel flow rate command is generated based on the first control signal and the correction signal. Therefore, it is possible to control the boiler (10) so as to more satisfy the operating conditions.

(4) In some embodiments, in the configuration described in (3) above,
When the measured value of the boiler load, the rate of change of the boiler load, and the change width of the boiler load satisfy the predetermined conditions, the first control signal acquisition unit (120) is more than the case where the predetermined conditions are not satisfied. A correction unit (160) that corrects the third control signal so as to reduce the fuel flow rate is included.

According to the configuration described in (4) above, when the predetermined conditions (conditions such as the value of the boiler load, the change rate of the boiler load, the change width of the boiler load, etc.) are satisfied, the first condition according to the boiler load condition is met. 3 The control signal is corrected so as to reduce the preceding fuel flow rate by the preceding fuel flow rate correction control as compared with the case where the predetermined condition is not satisfied. As a result, the correction for the third control signal is executed so as to reduce the preceding fuel flow rate, so that the fuel flow rate is more appropriately reduced from the preceding fuel flow rate supplied to the boiler (10), and thus the fuel consumption is reduced. It becomes possible.

In addition, the temperature distribution in the boiler (10) can be more optimized with respect to fluctuations in the boiler load. For example, when the boiler load is increased, it is possible to reduce the possibility that the steam temperature at the outlet of the fireplace or the steam temperature at the outlet of the primary superheater exceeds the allowable upper limit temperature according to the specifications of the heat exchanger. For example, when the boiler load is reduced, the outlet water supply temperature of the economizer can be lowered, and the possibility that the outlet water supply temperature of the economizer reaches the saturated steam temperature can be reduced.

(5) In some embodiments, in the configuration described in (4) above,
The correction unit (160) determines the amount of decrease in the fuel flow rate in the correction of the third control signal based on the heat reception amount indicated by the heat reception amount information.

According to the configuration described in (5) above, the amount of decrease in the fuel flow rate is determined based on the amount of heat received from the fluctuating heat from the outside, so that the fuel flow rate can be controlled more appropriately.

(6) In some embodiments, in the configuration described in any one of (1) to (5) above,
An opening control unit (170) for controlling the opening degree of the damper (56) provided in the bypass flow path (55) for bypassing the economizers (46, 47) is provided.
The opening degree control unit (170) is based on the difference between the outlet water supply temperature of the economizer and the saturated steam temperature and the reduction rate of the difference between the outlet water supply temperature of the economizer and the saturated steam temperature. The opening degree of the damper is controlled.

According to the configuration described in (6) above, the damper (55) provided in the bypass flow path (55) is based on the difference between the outlet water supply temperature of the economizer and the saturated steam temperature and the reduction rate of the difference. The opening degree of 56) is controlled. When the damper (56) is controlled to increase the opening degree, the high temperature gas flowing into the bypass flow path (55) increases and the high temperature gas flowing into the economizers (46, 47) decreases. The outlet water supply temperature of the economizers (46, 47) decreases. Therefore, it is possible to reduce the possibility that the outlet water supply temperature of the economizers (46, 47) reaches the saturated steam temperature and becomes steaming.

(7) In some embodiments, in the configuration described in any one of (1) to (6) above,
The heat receiving amount information acquisition unit (130) determines the heat receiving amount based on the temperature difference and the flow rate of the water supply at the positions before and after the position where heat is transferred from the heat medium that receives fluctuating heat from the outside to the water supply. calculate.

According to the configuration described in (7) above, the amount of heat received is determined by comparing the state of water supply before and after the position where the heat exchanger transfers heat from the heat medium that receives fluctuating heat from the outside to the water supply. Since it is calculated directly, the amount of heat received can be calculated more accurately.

(8) In some embodiments, in the configuration according to any one of (1) to (7) above, the fluctuating heat from the outside is the solar heat that condenses sunlight.

According to the configuration described in (8) above, even in the boiler (10) that utilizes the solar heat that condenses sunlight, the fuel flow rate supplied to the boiler (10) can be appropriately controlled.

(9) The boiler system (1) according to the embodiment of the present disclosure is
The boiler control device (100) according to any one of (1) to (8) above, and
A heat exchanger (83) that transfers heat from a heat medium circulation flow path (L6) for circulating a heat medium that receives fluctuating heat from the outside to the water supply.
A boiler that includes an economizer (46,47), a primary superheater (43), and a secondary superheater (42), and generates steam by heating the water supply that has exchanged heat with the heat medium by burning fuel. (10) and
To be equipped.

According to the configuration described in (9) above, a boiler system (1) capable of more appropriately controlling the fuel flow rate with respect to fluctuations in the amount of heat received from the outside is provided.

(10) The power plant (2) according to the embodiment of the present disclosure is
The boiler system (1) described in (9) above and
A steam turbine (61) that is rotationally driven by the steam generated by the boiler system (1), and
A generator (3) connected to the steam turbine (61) and generating electricity according to the rotation of the steam turbine (61).
To be equipped.

According to the configuration described in (10) above, there is provided a power plant (2) capable of more appropriately controlling the fuel flow rate with respect to fluctuations in the amount of heat received from fluctuating heat from the outside.

(11) The boiler control method according to the embodiment of the present disclosure is described.
It is a control method of a boiler that generates steam from water supply.
The step of acquiring the first control signal generated based on the base fuel flow rate signal generated based on the output target command and the third control signal according to the boiler load condition, and the step of acquiring the fuel flow rate of the fuel supplied to the boiler.
The step of acquiring heat reception amount information regarding the heat reception amount of fluctuating heat from the outside, and
A step of converting the heat receiving amount indicated by the acquired heat receiving amount information into the fuel flow rate and acquiring a correction signal for correcting the first control signal.
A step of outputting a fuel flow rate command for controlling the fuel flow rate based on the first control signal and the correction signal to which a delay element is added.
To be equipped.

According to the method described in (11) above, it is possible to control the boiler (10) so as to satisfy the operating conditions, and more appropriately with respect to fluctuations in the amount of heat received from fluctuating heat from the outside. It becomes possible to control the fuel flow rate.

1 Boiler system 2 Power plant 3 Generator 10 Coal-fired boiler (boiler)
11 Fireplace 12 Combustion device 13 Flue 21, 22, 23, 24, 25 Combustion burner 26, 27, 28, 29, 30 Pulverized charcoal supply pipe 31, 32, 33, 34, 35 Crusher 36 Air box 37 Air duct 38 Push-in ventilator (FDF)
41 Tertiary superheater (heat exchanger)
42 Secondary superheater (heat exchanger)
43 Primary superheater (heat exchanger)
44 Second reheater (heat exchanger)
45 First reheater (heat exchanger)
46 Section 2 Economizer (heat exchanger)
47 Section 1 Economizer (heat exchanger)
48 Gas duct 49 Air heater (air preheater)
50 Denitration device 51 Dust treatment device 52 Ventilator (IDF)
53 Chimney 55 Bypass flow path 56 Damper 60 Combustion gas passage 61 Steam turbine 62 High pressure turbine 63 Low pressure turbine 64 Condenser 65 Inlet header 66 Water supply pump 67 Intermediate header 68 Outlet header 69 Steam drum (steam water separator)
70 Inlet header 72 Outlet header 81 Heat receiving unit 82 Circulation pump 83 Heat exchanger 100 Boiler control device 110 Information acquisition unit 120 1st control signal acquisition unit 121, 123, 129, 145, 163, 171, 172 Comparer 122, 178 Adder 124, 125, 126, 164, 165, 166, 176 Function generator 127, 128, 167, 168, 169 Multiplier 130 Heat reception information acquisition unit 140 Correction signal acquisition unit 150 Fuel flow command unit 160 Correction unit 170 Open Degree control unit 173 PI control unit 174 P control unit 175, 177 Switching unit 179 Switch L1, L2 Water supply line L3, L4, L5 Steam line L6 Heat medium circulation flow path

Claims (11)

A boiler control device that produces steam from water supply.
The first control signal for acquiring the first control signal generated based on the base fuel flow rate signal generated based on the output target command and the third control signal according to the boiler load condition for the fuel flow rate of the fuel supplied to the boiler. Acquisition department and
A heat receiving amount information acquisition unit configured to acquire heat receiving amount information regarding the heat receiving amount of fluctuating heat from the outside,
A correction signal acquisition unit configured to convert the heat reception amount indicated by the heat reception amount information acquired by the heat reception amount information acquisition unit into the fuel flow rate and acquire a correction signal for correcting the first control signal. ,
A fuel flow rate command unit configured to output a fuel flow rate command for controlling the fuel flow rate based on the first control signal and the correction signal to which a delay element is added.
Boiler control device. The boiler control device according to claim 1, wherein the delay element is a primary delay element having a time constant of a change in the outlet water supply temperature of the economizer with respect to the change in the amount of heat received. The first control signal acquisition unit generates the first control signal based on the second control signal which further generates the base fuel flow rate signal based on the deviation of one or more steam temperatures. Boiler control device described in. When the measured value of the boiler load, the rate of change of the boiler load, and the range of change of the boiler load satisfy the predetermined conditions, the first control signal acquisition unit performs the fuel flow rate more than when the predetermined conditions are not satisfied. The boiler control device according to claim 3, further comprising a correction unit that corrects the third control signal so as to reduce. The boiler control device according to claim 4, wherein the correction unit determines the amount of decrease in the fuel flow rate in the correction of the third control signal based on the heat reception amount indicated by the heat reception amount information. An opening control unit for controlling the opening of a damper provided in the bypass flow path for bypassing the economizer is provided.
The opening degree control unit is based on the difference between the outlet water supply temperature of the economizer and the saturated steam temperature and the reduction rate of the difference between the outlet water supply temperature of the economizer and the saturated steam temperature. The boiler control device according to any one of claims 1 to 5, which controls the opening degree of the boiler. The heat receiving amount information acquisition unit calculates the heat receiving amount based on the temperature difference and the flow rate of the water supply at the positions before and after the position where heat is transferred from the heat medium that receives fluctuating heat from the outside to the water supply. The boiler control device according to any one of claims 1 to 6. The boiler control device according to any one of claims 1 to 7, wherein the fluctuating heat from the outside is solar heat that condenses sunlight. The boiler control device according to any one of claims 1 to 8.
A heat exchanger that transfers heat to the water supply from a heat medium circulation flow path for circulating a heat medium that receives fluctuating heat from the outside.
A boiler that includes an economizer, a primary superheater, and a secondary superheater, and generates steam by heating the water supply that has exchanged heat with the heat medium by burning fuel.
Boiler system with. The boiler system according to claim 9 and
A steam turbine that is rotationally driven by the steam generated by the boiler system,
A generator connected to the steam turbine and generating electricity according to the rotation of the steam turbine.
Power plant equipped with. It is a control method of a boiler that generates steam from water supply.
The step of acquiring the first control signal generated based on the base fuel flow rate signal generated based on the output target command and the third control signal according to the boiler load condition, and the step of acquiring the fuel flow rate of the fuel supplied to the boiler.
The step of acquiring heat reception amount information regarding the heat reception amount of fluctuating heat from the outside, and
A step of converting the heat receiving amount indicated by the acquired heat receiving amount information into the fuel flow rate and acquiring a correction signal for correcting the first control signal.
A step of outputting a fuel flow rate command for controlling the fuel flow rate based on the first control signal and the correction signal to which a delay element is added.
Boiler control method.

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