Unit count control device

Abstract

To provide a unit count control device capable of performing demand response while suppressing fluctuation in steam pressure.SOLUTION: A unit count control device controls a plurality of boilers, including one or more electric boilers and one or more fuel boilers. In a case where reduction control is performed to reduce an amount of steam generated by the one or more electric boilers based on power information even if the steam pressure is at a value that does not require a change in a combustion state of the boiler, the unit count control device performs combustion state change control to change the combustion state of at least one of the one or more fuel boilers before the reduction control is started.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a boiler number control device for controlling a plurality of boilers. [Background technology]

[0002] BACKGROUND ART Conventionally, there have been systems that control a plurality of boilers and the like installed in a facility based on a DR (Demand Response) command, which is a command to adjust the supply and demand of power from an aggregator system or the like (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-188498 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when a unit count control device receives a down DR command to reduce power consumption, it controls the number of electric boilers in operation in the facility, resulting in a decrease in steam generation. To compensate for this decrease, a fuel-fired boiler is started separately. However, the unit count control device controls multiple boilers according to fluctuations in steam pressure. Therefore, when an electric boiler stops and the steam pressure drops, the fuel-fired boiler is started, which could further reduce the steam pressure until steam is supplied.

[0005] Furthermore, when the unit count control device receives an up DR command to increase power usage, for example, it controls the number of electric boilers in operation in the facility to increase the amount of steam generated. However, the unit count control device operates the electric boilers and stops the fuel boilers in response to the increase in steam pressure, which could further increase the steam pressure until the fuel boilers are completely stopped.

[0006] The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a unit number control device that can perform demand response while suppressing fluctuations in steam pressure. [Means for solving the problem]

[0007] In order to achieve the above object, a number of boilers control device according to an aspect of the present invention is a number of boilers control device that controls a plurality of boilers including one or more electric boilers and one or more fuel-fired boilers, a steam pressure acquisition unit that acquires steam pressures of steam generated in the plurality of boilers; an electric power information acquisition unit that acquires information about electric power available in the plurality of boilers; a control unit that controls each of the plurality of boilers based on the steam pressure and the power information, When the control unit performs reduction control to reduce the amount of steam generated by the one or more electric boilers based on the power information even if the steam pressure is at a value that does not require a change in the combustion state of the boilers, the control unit performs combustion state change control to change the combustion state of at least one of the one or more fuel boilers before starting the reduction control.

[0008] According to the above configuration, the combustion state of at least one of the fuel boilers is changed based on the power information before the reduction control is started, so that it is possible to prevent the steam pressure from being lowered when the reduction control is performed.

[0009] Furthermore, as the combustion state change control, the control unit changes the combustion state of the fuel boiler that is not firing to pressure maintenance combustion.

[0010] According to the above configuration, the combustion state of the fuel boiler that is not firing is changed to pressure maintenance combustion, so that the amount of steam generated by the fuel boiler can be increased when the reduction control is started.

[0011] Also, the one or more fuel-fired boilers include a fuel-fired boiler having a first combustion position and a second combustion position that can generate a larger amount of steam than the first combustion position; As the combustion state change control, the control unit increases the number of fuel boilers whose combustion state is in the first combustion position among the fuel boilers.

[0012] According to the above configuration, the number of fuel boilers that are to be the first combustion positions increases, so that the amount of steam generated by the fuel boilers can be increased when the reduction control is started.

[0013] In addition, the control unit identifies the smaller of the differential steam amount between the amount of steam that can be generated by all of the one or more fuel boilers and the amount of steam generated by the fuel boilers among the one or more fuel boilers that are permitted to operate, and the amount of steam generated by the electric boilers among the one or more electric boilers that are permitted to operate, as the upper limit steam amount that can be reduced by the reduction control, and performs the reduction control within the range of this upper limit steam amount.

[0014] According to the above configuration, it is possible to prevent the amount of steam that cannot be supplemented by the fuel boiler or the amount of steam that can be produced by the electric boiler from being reduced by control.

[0015] In order to achieve the above object, a number of boilers control device according to an aspect of the present invention is a number of boilers control device that controls a plurality of boilers including one or more electric boilers and one or more fuel-fired boilers, a steam pressure acquisition unit that acquires steam pressures of steam generated in the plurality of boilers; an electric power information acquisition unit that acquires information about electric power available in the plurality of boilers; a control unit that controls each of the plurality of boilers based on the steam pressure and the power information, When the control unit performs an increase control to increase the amount of steam generated by the one or more electric boilers based on the power information even if the steam pressure is a value that does not require a change in the boiler combustion state, the control unit performs a decrease control to decrease the amount of steam generated by the one or more combustion boilers at the time when the amount of steam generated by the one or more electric boilers increases.

[0016] According to the above configuration, when increase control is performed based on power information, it is possible to prevent the steam pressure from increasing.

[0017] The timing at which the amount of steam generated by the one or more electric boilers increases is the timing at which the pressure in one of the electric boilers reaches or exceeds a predetermined value.

[0018] According to the above configuration, the reduction control can be performed at a timing when the amount of steam generated by the electric boiler increases reliably.

[0019] In addition, the control means identifies the smaller of the differential steam amount between the amount of steam that can be generated by all of the one or more electric boilers and the amount of steam generated by the electric boilers among the one or more electric boilers that are permitted to operate, and the amount of steam generated by the fuel boilers among the one or more fuel boilers that are permitted to operate, as the upper limit steam amount that can be increased by the increase control, and performs the increase control within the range of this upper limit steam amount.

[0020] According to the above configuration, it is possible to prevent an increase control from being performed in excess of the amount of steam that cannot be supplemented by the electric boiler or the amount of steam produced by the fuel boiler.

[0021] Furthermore, the information on the power available to the plurality of boilers is information that specifies not only the power supplied from the outside but also the amount of power generated within the facility in which the boiler is installed.

[0022] According to the above configuration, the electric boiler can be used to the maximum extent to generate steam. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a boiler system. [Figure 2] 10 is a flowchart for explaining a DR-related process performed by a unit count control device. [Figure 3] 10 is a diagram for explaining a specific example of state transition of a fuel boiler group and an electric boiler group from the time when a downward DR request signal is received until the downward DR is performed. FIG. [Figure 4] 10 is a diagram for explaining a specific example of state transition of a fuel boiler group and an electric boiler group from the time when a downward DR request signal is received until the downward DR is performed. FIG. [Figure 5] 10A and 10B are diagrams for explaining specific examples of state transitions of the fuel boiler group and the electric boiler group after receiving an upward DR request signal and performing upward DR. [Figure 6] 10 is a flowchart for explaining a downward DR possible power amount calculation process performed by the unit count control device. [Figure 7] 10 is a flowchart for explaining an upward DR possible power amount calculation process performed by the unit count control device. DETAILED DESCRIPTION OF THE INVENTION

[0024] <Overview of the configuration>

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a schematic configuration of a boiler system 1 according to this embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the boiler system 1 includes a plurality of boilers 2, a steam header 4 connected to each of the plurality of boilers 2 via a steam pipe 3, a steam pressure sensor 5 that measures the pressure value inside the steam header 4 (hereinafter also referred to as "header pressure value"), and a unit number control device 8 that controls the combustion state of each of the plurality of boilers 2.

[0026] The multiple boilers 2 include multiple electric boilers 2A (hereinafter also referred to as electric boiler groups) that generate steam using Joule heat from electricity, and fuel boilers 2B (hereinafter also referred to as fuel boiler groups) that generate steam by burning fuel (gas, liquid fuel, etc.). Each of the multiple electric boiler groups can be controlled to an operating state in which, when activated, the amount of steam generated becomes a predetermined amount (for example, 500 kg / h). Each of the multiple electric boiler groups can be switched between an operating state and a stopped state (standby state).

[0027] Each of the plurality of fuel-fired boiler groups can be controlled to one of a plurality of combustion states in which the combustion amount (load factor) in the boiler body varies in stages. The plurality of combustion states include, for example, a pressure-maintaining combustion state in which the state immediately before steam generation is maintained, a low combustion state (an example of a first combustion position) in which the steam generation amount is a predetermined amount (e.g., 500 kg / h), and a high combustion state (an example of a second combustion position) in which the steam generation amount is a specific amount (e.g., 1000 kg / h). Each of the plurality of fuel-fired boiler groups can be switched to one of the high combustion state, low combustion state, pressure-maintaining combustion state, and combustion-stop state (combustion standby).

[0028] In this embodiment, an example is shown in which the amount of steam generated when the electric boiler 2A is operating is the same as the amount of steam generated when the fuel boiler 2B is in a low combustion state, and the amount of steam generated when the electric boiler 2A is operating is the same as the difference between the amount of steam generated when the fuel boiler 2B is in a low combustion state and the amount of steam generated when the fuel boiler 2B is in a high combustion state, but this is not limited to this and each may be set to a different amount.

[0029] The steam generated by each of the multiple boilers 2 is sent to a steam header 4 via steam piping 3. The steam header 4 collects the steam generated by each of the multiple boilers 2 and supplies the steam to a user facility 11 that uses the steam via a supply pipe 10. The steam pressure sensor 5 transmits a steam pressure signal for identifying the measured header pressure value to the unit count control device 8 via a signal line 6.

[0030] The number of units control device 8 includes a first number of units control device 8A that controls the state of a group of multiple electric boilers, and a second number of units control device 8B that controls the state of a group of multiple fuel-fired boilers. The first number of units control device 8A transmits control signals for controlling each of the multiple electric boilers 2A via signal line 9A. Each of the multiple electric boilers 2A is controlled to be in a state (operating, stopped, etc.) specified by the received control signal. The second number of units control device 8B transmits control signals for controlling each of the multiple fuel-fired boilers 2B via signal line 9B. Each of the multiple fuel-fired boilers 2B sets a combustion state specified by the received control signal and controls the boiler to be in that combustion state. In addition, each of the multiple boilers 2 transmits a boiler body pressure signal for specifying the pressure value inside the boiler body to the first number of units control device 8A and the second number of units control device 8B, which are the control sources, via signal line 9.

[0031] The first number of units control device 8A and the second number of units control device 8B control the state of each of the multiple boilers 2 so that the header pressure value identified from the steam pressure signal becomes a pressure value corresponding to a preset steam volume (or a pressure range corresponding to a preset steam volume), and supply steam to the usage equipment 11. Furthermore, the first number of units control device 8A and the second number of units control device 8B control the state of each of the multiple boilers 2 based on control signals from the power demand monitoring device 12, even if the header pressure value is a value that does not require a change in the state of each of the multiple boilers 2. The first number of units control device 8A and the second number of units control device 8B each include at least a steam pressure acquisition unit that acquires the header pressure value and the boiler body pressure value from each boiler, a power information acquisition unit that acquires control signals from the power demand monitoring device 12, and a control unit that controls each of the multiple boilers based on the steam pressure, the control signal from the power demand monitoring device 12, etc.

[0032] The power demand monitoring device 12 corresponds to a so-called aggregator, and for example, provides support for controlling the multiple boilers 2 so that the amount of power used in a facility such as a factory in which the boiler system 1 is installed does not exceed the contracted power amount as much as possible and converges to the contracted power amount. Note that the power demand monitoring device 12 may be included in the boiler system 1, but is not limited to this, and may be located within the same facility without being included in the boiler system 1, or may be located outside the facility.

[0033] The power demand monitoring device 12 transmits a control signal (hereinafter also referred to as a downward DR request signal) to the first number of units control device 8A and the second number of units control device 8B to perform a downward demand response (hereinafter also referred to as a downward DR request signal) requesting a reduction in power demand when, for example, the amount of power usage after a predetermined time (e.g., 30 minutes) is likely (predicted) to exceed the contracted power amount, taking into account the power used by equipment other than the electric boiler in the facility and the power generated in the facility. The downward DR request signal is a signal that includes information specifying, for example, the amount of power requested to be reduced (or the amount of power exceeding the contracted power amount) and the start time of the downward DR. In response to the downward DR request signal, the first number of units control device 8A and the second number of units control device 8B control the electric boiler 2A to reduce the amount of steam generated and the fuel boiler 2B to increase the amount of steam generated.

[0034] Furthermore, the power demand monitoring device 12 transmits a control signal (hereinafter also referred to as an "upward DR request signal") to the first number of units control device 8A and the second number of units control device 8B to perform an upward demand response (hereinafter also referred to as an "upward DR") requesting an increase in power demand when, for example, the amount of power usage after a predetermined time is likely to fall below the contracted amount of power, taking into account the power used by equipment other than the electric boiler in the facility and the power generated in the facility. The upward DR request signal is a signal that includes information specifying, for example, the amount of power requested to be increased (or the amount of power below the contracted amount of power) and the start time of the upward DR. In response to the upward DR request signal, the first number of units control device 8A and the second number of units control device 8B increase the amount of steam generated by the electric boiler 2A and decrease the amount of steam generated by the fuel boiler 2B.

[0035] For example, when the start time of the down DR arrives, the unit count control device controls the number of operating electric boilers installed in the facility to reduce the amount of steam generated, and therefore it is necessary to control the system to compensate for this reduction by starting up a separate fuel boiler, etc. However, because conventional unit count control devices control multiple boilers in accordance with fluctuations in header pressure values, etc., they control the fuel boiler to increase the amount of steam generated in response to the drop in steam pressure caused by the electric boiler being stopped, which could result in a further drop in steam pressure before the amount of steam generated actually increases.

[0036] Furthermore, when the start time of the upward DR arrives, the unit count control device increases the number of operating electric boilers installed in the facility, thereby increasing the amount of steam generated. However, because conventional unit count control devices control multiple boilers in response to fluctuations in header pressure values, etc., they operate the electric boilers and, in response to an increase in steam pressure, they control the amount of steam generated by the fuel boilers to decrease the amount of steam generated by the fuel boilers, which could cause the steam pressure to increase further before the amount of steam generated by the fuel boilers reaches an appropriate level.

[0037] Therefore, in the number control device 8 of the boiler system 1 in this embodiment, when a downward DR request signal is received, for example, a downward DR start time (after a predetermined time) is set, and the first number control device 8A calculates the number of electric boilers 2A to be stopped in response to the downward DR request signal, and the second number control device 8B performs fuel boiler increase preparation processing (an example of combustion state change control) in advance so that the amount of steam generated by the fuel boilers 2B can be increased immediately from the downward DR start time. Then, when the downward DR start time arrives, the first number control device 8A controls the target electric boiler 2A to a stopped state (an example of reduction control that reduces the amount of steam generated by the electric boiler), and the second number control device 8B performs downward DR processing to control the target fuel boiler 2B to a state where the amount of steam is increased.

[0038] Furthermore, when the number of units control device 8 of the boiler system 1 receives an upward DR request signal, it sets, for example, an upward DR start time (after a predetermined time), and the first number of units control device 8A calculates the number of electric boilers 2A to operate in response to the upward DR request signal. When the upward DR start time arrives, the first number of units control device 8A controls the target electric boilers 2A to operate (an example of increase control to increase the amount of steam generated by the electric boilers). Meanwhile, the second number of units control device 8B performs upward DR processing, determining whether steam supply (steam amount increase) has actually occurred based on the boiler body pressure of the newly operated electric boiler 2A, and controlling the fuel boiler 2B to generate a reduced amount of steam depending on the number of electric boilers 2A that supplied steam (or the amount of steam generated). Below, an example of DR-related processing for performing downward DR processing and upward DR processing by the number of units control device 8 is described with reference to Figures 2 to 5.

[0039] 2 is a flowchart for explaining DR-related processing performed by the number of units control device 8. The first number of units control device 8A and the second number of units control device 8B each execute DR-related processing. First, processing related to downward DR will be explained. In step S11, it is determined whether a downward DR request signal has been received from the power demand monitoring device 12. If it is determined that a downward DR request signal has not been received, the process proceeds to step S21. On the other hand, if it is determined that a downward DR request signal has been received, in step S12, a downward DR start time specified from the downward DR request signal is set.

[0040] Next, in step S13, it is determined whether the number of units control device 8 executing the DR-related process is the first number of units control device 8A that controls the electric boiler 2A. If it is determined in step S13 that it is the first number of units control device 8A, in step S14, the number of electric boilers 2A to be shut down is calculated based on the amount of power for which suppression is requested, which is identified from the down-DR request signal. For example, the value obtained by dividing the amount of power for which suppression is requested by the maximum power consumption per electric boiler (rounded down to the nearest whole number) is used as the number of electric boilers 2A to be shut down. On the other hand, if it is not determined in step S13 that it is the first number of units control device 8A, in step S15, fuel boiler increase preparation process is performed to enable the amount of steam generated by the fuel boiler 2B to be increased (for example, to a pressure-maintaining combustion state that maintains the state immediately before steam supply, or a low combustion state) from the down-DR start time, based on the amount of power for which suppression is requested, which is identified from the down-DR request signal. A specific example of the fuel boiler increase preparation process will be described later with reference to FIGS. 3 and 4.

[0041] In step S16, it is determined whether the set downward DR start time has been reached. Step S16 is repeated until it is determined that the downward DR start time has been reached. If it is determined that the downward DR start time has been reached, it is determined in step S17 whether the number of units control device 8 executing the DR-related process is the first number of units control device 8A that controls the electric boiler 2A. If it is determined in step S17 that it is the first number of units control device 8A, in step S18, the number of electric boilers 2A calculated in step S14 is controlled to a stopped state. On the other hand, if it is not determined in step S17 that it is the first number of units control device 8A, in step S19, the fuel boiler 2B that was the target of the combustion boiler increase preparation process in step S15 is controlled to a combustion state that increases the amount of steam (for example, from a pressure-maintaining combustion state to a low combustion state or a high combustion state, or from a low combustion state to a high combustion state).

[0042] Next, the process related to the upward DR will be described. In step S21, it is determined whether or not an upward DR request signal has been received from the power demand monitoring device 12. If it is determined that an upward DR request signal has not been received, the DR-related process is terminated. On the other hand, if it is determined that an upward DR request signal has been received, in step S22, an upward DR start time specified from the upward DR request signal is set.

[0043] Next, in step S23, it is determined whether the number of units control device 8 executing the DR-related process is the first number of units control device 8A that controls the electric boiler 2A. If it is determined in step S23 that it is the first number of units control device 8A, then in step S24, the number of electric boilers 2A to be operated is calculated based on the amount of power for which an increase is requested, which is identified from the up-DR request signal. For example, the value obtained by dividing the amount of power for which an increase is requested by the maximum power consumption per electric boiler (decimals may be rounded down or rounded up) is used as the number of electric boilers 2A to be operated. On the other hand, if it is not determined in step S23 that it is the first number of units control device 8A, the process proceeds to step S25.

[0044] In step S25, it is determined whether the set start time of the upward DR has been reached. Step S25 is repeated until it is determined that the start time of the upward DR has been reached. When it is determined that the start time of the upward DR has been reached, it is determined in step S26 whether the number of units control device 8 executing the DR-related process is the first number of units control device 8A that controls the electric boiler 2A. When it is determined in step S26 that the first number of units control device 8A is the first number of units control device 8A, in step S27, the number of electric boilers 2A calculated in step S24 is controlled to an operating state, and in step S28, information for identifying the steam volume of the electric boiler 2A that has entered a steam supply state capable of supplying steam is transmitted to the second number of units control device 8B. Note that in step S28, whether the steam supply state has been reached is determined based on whether a predetermined value has been reached based on the boiler body pressure of the electric boiler 2A.

[0045] On the other hand, if it is not determined in step S26 that the first number of units control device 8A is the controller, in step S29, a fuel boiler reduction process is performed to reduce the amount of steam generated by the fuel boiler 2B according to the steam amount when the electric boiler 2A, which has entered the steam supply state based on information from the first number of units control device 8A, and the DR-related process is terminated. Note that the steam amount reduced by the fuel boiler reduction process is reduced so that the amount of steam generated by the fuel boiler 2B is equal to or less than the steam amount of the electric boiler 2A, which has entered the steam supply state based on information from the first number of units control device 8A.

[0046] Next, with reference to Figures 3 and 4, a specific example of state transitions of the fuel boiler group and the electric boiler group from the time a downward DR request signal is received until a downward DR is performed will be described. Also, with reference to Figure 5, a specific example of state transitions of the fuel boiler group and the electric boiler group after an upward DR request signal is received and an upward DR is performed will be described. In Figures 3 to 5, etc., the state of the fuel boiler group is shown on the left, and the state of the electric boiler group is shown on the right, indicating a transition to a lower state over time. Also, in the example of Figures 3 to 5, etc., a total of six fuel boilers, No. 1 to No. 6, are installed as the fuel boiler group, and a total of eight electric boilers, No. 1 to No. 8, are installed as the electric boiler group. Note that, as mentioned above, the steam generation rate per electric boiler is 500 kg / h, and the steam generation rate per fuel boiler is 500 kg / h in the low combustion state, 1000 kg / h in the high combustion state, and 0 kg / h in the pressure-maintaining combustion state. In the following description, it is assumed that the steam generation rate per fuel boiler is 500 kg / h in the low combustion state, 1000 kg / h in the high combustion state, and 0 kg / h in the pressure-maintaining combustion state.

[0047] Figure 3 shows an example in which the fuel boiler increase preparation process in step S15 in Figure 2 controls a stopped fuel boiler (a fuel boiler that is not firing) to a pressure-maintaining combustion state, thereby enabling an increase in the amount of steam generated by fuel boiler 2B (enabling steam supply) from the start time of the downdraft. Figure 3(a) shows the state of each boiler before receiving a downdraft request signal, with fuel boilers #1 and #2 in a high-combustion state (flame symbols in columns H and L in the figure), #3 and #4 in a low-combustion state (flame symbols in column L only in the figure), #5 and #6 in a stopped state (both columns H and L are blank in the figure), and #1 through #6 in an operating state (flame symbols in the figure), with #7 and #8 in a stopped state (blank in the figure). In this state, the examples in Figures 3 and 4 show a case in which a downdraft request signal is received requesting a reduction in the amount of electricity required to operate the four electric boilers.

[0048] When a downdraft request signal requesting a reduction in the amount of electricity required to operate four electric boilers is received, step S14 in Figure 2 calculates the number of electric boilers to be shut down as four. In step S15, the fuel boiler increase preparation process is performed to immediately increase the steam generation rate (2000 kg / h) per four electric boilers (to allow steam supply) when the downdraft start time arrives. Combustion boilers 2B Nos. 3 and 4 are in a low combustion state, so they can already be switched to a high combustion state at (or just before) the downdraft start time, thereby increasing their steam generation rate by 1000 kg / h. Meanwhile, Nos. 5 and 6 are shut down, so steam supply is required, preventing immediate increases in their steam generation rate. For this reason, Figure 3(b) shows an example in which, in the fuel boiler increase preparation process in step S15 in Figure 2, No. 5 is placed in a pressure-maintaining combustion state in advance, and then switched to a high combustion state at (or just before) the downdraft start time, thereby allowing a 1000 kg / h increase.

[0049] Figure 3(c) shows that after a predetermined time (e.g., 3 to 5 minutes) has passed since No. 5 was transitioned to a pressure-maintaining combustion state, the pressure-maintaining combustion state was reached, and the steam volume was immediately increased.

[0050] Figure 3(d) shows that when the time for starting the downward DR is reached, a total of four electric boilers 2A, Nos. 3 to 6, which are the target in step S18 of Figure 2, are stopped, while in step S19, fuel boiler No. 5, which is the target of the fuel boiler increase preparation process, is controlled to a high combustion state, and fuel boilers Nos. 3 and 4 are controlled to a high combustion state.

[0051] While Fig. 3 illustrates the case where a down DR request signal requesting a reduction in the amount of power required to operate four electric boilers is received, as another example, when a down DR request signal requesting a reduction in the amount of power required to operate three electric boilers is received, electric boiler No. 5 may be controlled to a pressure-maintaining combustion state at the timing shown in Fig. 3(b), and electric boilers Nos. 3 and 4 may be controlled to a high combustion state and electric boiler No. 5 may be controlled to a low combustion state at the timing shown in Fig. 3(d). Also, when a down DR request signal requesting a reduction in the amount of power required to operate five electric boilers is received, electric boilers Nos. 5 and 6 may be controlled to a pressure-maintaining combustion state at the timing shown in Fig. 3(b), and electric boilers Nos. 3 and 4 may be controlled to a high combustion state, electric boiler No. 5 may be controlled to a high combustion state and electric boiler No. 6 may be controlled to a low combustion state at the timing shown in Fig. 3(d).

[0052] FIG. 4 shows an example (different from FIG. 3 ) in which the fuel boiler increase preparation process in step S15 of FIG. 2 first controls the fuel boilers that were in a stopped state to a combustion state, and when the fuel boilers controlled to the combustion state switch to a steam supply state, controls the fuel boilers that were in a high combustion state to a low combustion state (increasing the number of fuel boilers that switch to a low combustion state (first combustion position)). This makes it possible to increase the amount of steam generated by fuel boiler 2B (enables steam supply) from the start time of the down DR. FIG. 4(a) shows the same state as FIG. 3(a). FIG. 4(b) shows that the fuel boiler No. 5 has been transitioned to a low combustion state in advance in the fuel boiler increase preparation process in step S15 of FIG. 2. FIG. 4(c) shows that the fuel boiler No. 2, which was in a high combustion state, is controlled to a low combustion state when it is determined that the fuel boiler No. 5 has switched to a steam supply state based on the boiler body pressure in the fuel boiler increase preparation process in step S15 of FIG. 2. This resulted in the No. 2 and No. 5 combustion boilers entering a low combustion state, making it possible to instantly increase the amount of steam produced without causing any significant fluctuations in the amount of steam generated.

[0053] Figure 4(d) shows that when the time for starting the downward DR is reached, a total of four electric boilers 2A, Nos. 3 to 6, which are the target in step S18 of Figure 2, are stopped, while in step S19, fuel boilers Nos. 2 and 5, which are the target of the fuel boiler increase preparation process, are controlled to a high combustion state, and fuel boilers Nos. 3 and 4 are controlled to a high combustion state.

[0054] While Fig. 4 illustrates the case where a down-DR request signal requesting a reduction in the amount of power required to operate four electric boilers is received, as another example, when a down-DR request signal requesting a reduction in the amount of power required to operate three electric boilers is received, boiler No. 5 may be controlled to a low combustion state at the timing shown in Fig. 4(b), boiler No. 2 may be controlled to a low combustion state at the timing shown in Fig. 4(c) (when boiler No. 5 enters the steam supply state), and boilers Nos. 2 to 4 may be controlled to a high combustion state at the timing shown in Fig. 4(d). Also, when a down-DR request signal requesting a reduction in the amount of power required to operate five electric boilers is received, boilers Nos. 5 and 6 may be controlled to a low combustion state at the timing shown in Fig. 4(b), boilers Nos. 1 and 2 may be controlled to a low combustion state in that order at the timing shown in Fig. 4(c) (when boilers Nos. 5 and 6 enter the steam supply state), and boilers Nos. 1 to 5 may be controlled to a high combustion state at the timing shown in Fig. 4(d).

[0055] Next, a specific example of the state transition of the fuel boiler group and the electric boiler group after receiving an upward DR request signal and performing an upward DR will be described with reference to Fig. 5. Fig. 5(a) shows the state of each boiler before receiving an upward DR request signal, and illustrates a case where, among the fuel boilers, Nos. 1 to 3 are in a high combustion state, No. 4 is in a low combustion state, and Nos. 5 and 6 are stopped, and among the electric boilers, Nos. 1 to 3 are in an operating state, and Nos. 4 to 8 are stopped. In this state, the example of Fig. 5 illustrates a case where an upward DR request signal is received requesting an increase in the amount of power required to operate the four electric boilers.

[0056] When the upward DR request signal is received, the number of electric boilers to be operated is calculated as four in step S24 of Fig. 2, and it is assumed that electric boilers No. 4 to No. 7 are controlled to be in operation. Thereafter, when the upward DR start time arrives, the target electric boilers No. 4 to No. 7 are controlled to be in operation in step S27 of Fig. 2, as shown in Fig. 5(b).

[0057] The time required for electric boilers No. 4 to No. 7 to enter steam supply mode after being switched to operation varies from one boiler to another, depending on the boiler body temperature at the time, their installation position, etc. Figure 5(c) shows the timing when electric boiler No. 4, out of electric boilers No. 4 to No. 7, entered steam supply mode. This increases the amount of steam generated, so fuel boiler No. 3 is controlled to a low combustion state, as shown in Figure 5(c).

[0058] Figures 5(d) to 5(f), like Figure 5(c), show how No. 2 is controlled to a low combustion state in accordance with No. 5 entering the steam supply state, No. 1 is controlled to a low combustion state in accordance with No. 6 entering the steam supply state, and No. 4 is controlled to a stopped state in accordance with No. 7 entering the steam supply state. Note that the example control shown in Figures 5(c) to 5(f) is performed by the fuel boiler reduction processing in step S29.

[0059] Note that Figure 5 illustrates the case where an upward DR request signal is received requesting an increase in the amount of electricity required to operate four electric boilers. However, as another example, if an upward DR request signal is received requesting an increase in the amount of electricity required to operate three electric boilers, electric boilers 4 to 6 may be controlled to the operating state at the timing shown in Figure 5(b), and fuel boilers 1 to 3 may be controlled to the low combustion state in turn each time electric boilers 4 to 6 enter the steam supply state, or fuel boiler 4 may be controlled to the stopped state → fuel boiler 3 to the low combustion state → fuel boiler 3 to the stopped state each time electric boilers 4 to 6 enter the steam supply state. Furthermore, when an upward DR request signal is received requesting an increase in the amount of electricity required to operate the five electric boilers, electric boilers 4 to 8 are controlled to the operating state at the timing shown in Figure 5(b), and each time electric boilers 4 to 8 enter the steam supply state, fuel boilers 1 to 3 are controlled to the low combustion state in turn, and then fuel boilers 3 and 4 may be controlled to the stopped state in turn, or each time electric boilers 4 to 8 enter the steam supply state, fuel boiler 4 may be controlled to the stopped state → fuel boiler 3 to the low combustion state → fuel boiler 3 to the stopped state → fuel boiler 2 to the low combustion state → fuel boiler 2 to the stopped state.

[0060] In this embodiment, the number control device 8 calculates and sets the lowering DR possible power amount, which is the upper limit of the amount of power that can be suppressed by lowering DR, and the upper limit of the amount of power that can be increased by raising DR, every predetermined time (for example, 30 minutes), depending on the current operating status (steam generation amount) of each electric boiler and fuel boiler, and performs demand response in response to the lowering DR request signal or the upper DR request signal from the power demand monitoring device 12, with the lowering DR possible power amount and the upper DR possible power amount as the upper limit. However, the number control device 8 is not limited to this, and for example, when it receives a downward DR request signal or an upward DR request signal from the power demand monitoring device 12 (for example, when it judges YES in step S11 described later or when it judges YES in step S21), it may calculate and set the downward DR possible power amount, which is the upper limit of the amount of power that can be suppressed by downward DR, and the upward DR possible power amount, which is the upper limit of the amount of power that can be increased by upward DR, depending on the current operating status (steam generation amount) of each electric boiler and fuel boiler, and perform demand response with the downward DR possible power amount and the upward DR possible power amount as the upper limit.

[0061] 6 is a flowchart for explaining the process of calculating the amount of power available for downward DR performed by the unit count control device 8. The process of calculating the amount of power available for downward DR is performed every time a predetermined time elapses, and as long as it is performed by the unit count control device 8, it may be performed by either the first unit count control device 8A or the second unit count control device 8B, or may be performed by both.

[0062] First, in step S31, it is determined whether the difference obtained by subtracting the current steam generation rate of the operating fuel boiler 2B (e.g., 3000 kg / h in the case of FIG. 3(a), an example of the steam generation rate of the fuel boiler that is the object of operation permission) from the maximum steam generation rate of the multiple fuel boilers 2B (e.g., 6000 kg / h in the case of FIG. 3(a), an example of the steam generation rate of the fuel boiler that is the object of operation permission) is equal to or less than the current steam generation rate of the operating electric boiler 2A (e.g., 3000 kg / h in the case of FIG. 3(a), an example of the steam generation rate of the electric boiler that is the object of operation permission). In other words, it is determined whether the current steam generation rate of the electric boiler 2A can be supplemented by the surplus steam from the fuel boiler 2B. Note that the current steam generation rate of the operating fuel boiler 2B and the current steam generation rate of the operating electric boiler 2A are not limited to the current steam generation rate, but may be an average value of the steam generation rate over a recent predetermined period, a value obtained by performing predetermined data processing, or the like.

[0063] If the determination in step S31 is YES (complementation is not possible), then in step S32, a differential value obtained by subtracting the current steam generation amount by the operating fuel boiler 2B from the maximum steam generation amount of the multiple fuel boilers 2B is set as the steam generation amount that can be reduced by reduction control (an example of an upper limit steam generation amount that can be reduced by reduction control).On the other hand, if the determination in step S31 is NO (complementation is possible), then in step S33, the current steam generation amount by the operating electric boiler 2A is set as the steam generation amount that can be reduced by reduction control.

[0064] Next, in step S34, the value (rounded down to the nearest integer) obtained by dividing the amount of steam available for down DR set in step S32 or step S33 by the maximum amount of steam generated by one electric boiler 2A is set as the number of electric boilers to be reduced, which is the upper limit of the number of electric boilers 2B that can be reduced during down DR. In step S35, the difference obtained by subtracting the amount of power generated within the facility from the amount of power used throughout the facility in which the boiler system 1 is installed is set as the amount of externally purchased power.

[0065] In step S36, it is determined whether the product of the number of electric boilers to be reduced during downward DR, set in step S34, and the maximum power consumption per electric boiler 2A is greater than the amount of externally purchased power set in step S35. That is, it is determined whether the amount of power for the reduced number of electric boilers during downward DR is greater than the amount of externally purchased power and therefore whether the amount of power can be reduced by the amount of reduced number of electric boilers during downward DR. If the result of step S36 is YES (the amount of power cannot be reduced by the amount of reduced number of electric boilers during downward DR), the amount of externally purchased power is set as the amount of power that can be reduced during downward DR in step S37, and the calculation process for the amount of power that can be reduced during downward DR is terminated. On the other hand, if the result of step S36 is NO (the amount of power can be reduced by the amount of reduced number of electric boilers during downward DR), the amount of power that can be reduced during downward DR is set as the amount of power that can be reduced during downward DR in step S38, and the calculation process for the amount of power that can be reduced during downward DR is terminated.

[0066] 7 is a flowchart for explaining the upward DR possible power amount calculation process performed by the unit count control device 8. The upward DR possible power amount calculation process is performed every time a predetermined time elapses, and as long as it is performed by the unit count control device 8, it may be performed by either the first unit count control device 8A or the second unit count control device 8B, or may be performed by both.

[0067] First, in step S41, it is determined whether the difference obtained by subtracting the current steam generation rate of the operating electric boiler 2A (e.g., 3000 kg / h in the case of FIG. 3(a), an example of the steam generation rate of the electric boiler that is the subject of operation permission) from the maximum steam generation rate of the multiple electric boilers 2A (e.g., 4000 kg / h in the case of FIG. 3(a), an example of the steam generation rate of the electric boiler that is the subject of operation permission) is equal to or less than the current steam generation rate of the operating fuel boiler 2B (e.g., 3000 kg / h in the case of FIG. 3(a), an example of the steam generation rate of the fuel boiler that is the subject of operation permission). In other words, it is determined whether the current steam generation rate of the fuel boiler 2B can be supplemented by the surplus steam from the electric boiler 2A. Note that the current steam generation rate of the operating electric boiler 2A and the current steam generation rate of the operating fuel boiler 2B are not limited to the current steam generation rate, but may be an average value of the steam generation rate over a recent predetermined period, a value obtained by performing predetermined data processing, or the like.

[0068] If the determination in step S41 is YES (complementation is not possible), then in step S42, a difference value obtained by subtracting the current steam generation amount by the operating electric boiler 2A from the maximum steam generation amount of the multiple electric boilers 2A is set as the steam generation amount capable of upward DR. On the other hand, if the determination in step S41 is NO (complementation is possible), then in step S43, the current steam generation amount by the operating fuel boiler 2B is set as the steam generation amount capable of upward DR (an example of an upper limit steam generation amount that can be increased by increase control).

[0069] Next, in step S44, the value (rounded down to the nearest integer) obtained by dividing the amount of steam capable of upward DR set in step S42 or step S43 by the maximum amount of steam generated by one electric boiler 2A is set as the number of additional electric boilers, which is the upper limit on the number of electric boilers that can be added during upward DR. In step S45, the value obtained by multiplying the number of additional electric boilers during upward DR set in step S44 by the maximum power consumption per electric boiler 2A is set as the amount of power capable of upward DR, and the process of calculating the amount of power capable of upward DR is terminated.

[0070] According to the number control device 8 in the above-described embodiment, the processing of steps S11 to S19 in FIG. 2 is performed, and by the time the electric boiler is stopped in step S18 based on the reception of a lowering DR request signal, the fuel boiler increase preparation processing is performed in step S15, so that it is possible to prevent the steam pressure from decreasing when the electric boiler is stopped in step S18.

[0071] Furthermore, by transitioning to a pressure-maintaining combustion state as shown in FIG. 3 as a fuel boiler increase preparation process, the amount of steam generated by the fuel boiler can be increased along with the stop control of the electric boiler.

[0072] Furthermore, by increasing the number of fuel boilers in a low combustion state as shown in FIG. 4 as a fuel boiler increase preparation process, the amount of steam generated by the fuel boilers can be increased along with the shutdown control of the electric boilers.

[0073] Furthermore, as shown in steps S31 to S33 in FIG. 6, the amount of steam that can be used for lowering the DR is set as the upper limit by subtracting the current steam generation amount of the fuel boiler from the maximum steam generation amount of the fuel boiler, which prevents the electric boiler from being shut down due to the upper limit steam generation amount exceeding the limit and becoming unable to be supplemented by the fuel boiler.

[0074] According to the number control device 8 in the above-described embodiment, the processing of steps S21 to S29 in FIG. 2 is performed, and a fuel boiler reduction process is performed to reduce the amount of steam generated by the combustion boiler each time the amount of steam generated by the newly started electric boiler increases, thereby preventing the steam pressure of the steam from increasing.

[0075] Furthermore, the amount of steam generated by the electric boiler increases when the pressure inside the electric boiler reaches a predetermined value or higher, so the amount of steam generated by the combustion boiler can be reduced at a time when the amount of steam generated by the electric boiler is reliably increasing.

[0076] Furthermore, as shown in steps S41 to S43 in FIG. 7, the amount of steam that can be used for the upward DR is set as the upper limit by subtracting the current amount of steam generated by the electric boiler from the maximum amount of steam generated by the electric boiler, which prevents the amount of steam generated by the combustion boiler from being reduced beyond the upper limit steam amount that cannot be supplemented by the electric boiler.

[0077] Furthermore, the power demand monitoring device 12 transmits a down DR request signal or an up DR request signal based on a prediction of the possibility of exceeding or falling short of the contracted amount of power, taking into account not only the amount of power supplied by the power company but also the amount of power generated within the facility. This allows the electric boiler to be used to its full potential to generate steam.

[0078] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible. Modifications of the above-described embodiment that can be applied to the present invention will be described below.

[0079] In the boiler system 1 of the above embodiment, an example has been described in which two or more electric boilers and two or more fuel boilers are included, but the system is not limited to this and may include at least one electric boiler and one or more fuel boilers. Also, while the number of units control device has been exemplified by a first number of units control device for electric boilers and a second number of units control device for fuel boilers, the system is not limited to this and may be controlled by a single number of units control device shared by both electric boilers and fuel boilers. In addition, while the electric boiler has been described as being controllable between an operating state and a stopped state, it is not limited to this, and may be controllable to a plurality of operating states with different steam generation rates, and may further be controllable to a pressure-maintaining operating state that maintains the state immediately before steam generation.In addition, the fuel boiler has been described as being controllable to any of a high combustion state, a low combustion state, a pressure-maintaining combustion state, and a combustion-stopped state, but it is not limited to this, and may further be controllable to a medium combustion state.

[0080] In the boiler system 1 according to the above embodiment, an example has been described in which the processes shown in steps S12 to S15 are performed when a lowering DR request signal is received, as shown in step S11 in Fig. 2. However, the processes shown in steps S12 to S15 may be performed at a time that is longer (e.g., 5 minutes) than the time (e.g., 4 minutes) required for the fuel boiler to go from a stopped state to the internal pressure of the boiler in a pressure-maintaining combustion state, before the lowering DR start time. Furthermore, in the DR-related processing of Figure 2, an example is shown in which, when the start time of the downward DR is reached, the processing in step S18 and the processing in step S19 are performed simultaneously depending on whether it is the first number control device or not. However, this is not limited to this. For example, when the start time of the downward DR is reached, the first number control device may perform the processing in step S18, and the second number control device may perform the processing in step S19 in response to a decrease in header pressure based on the header pressure value. Furthermore, in the DR-related processing in Figure 2, an example is shown in which the first number control device simultaneously stops the target electric boilers in step S18 when the downward DR start time is reached, but this is not limited to this. For example, starting a few minutes before the downward DR start time is reached, the first number control device may stop the electric boilers one by one in step S18, and at the same time the second number control device may change the combustion state of some fuel boilers in step S19, so that when the downward DR start time is reached, all the target electric boilers are stopped.

[0081] In addition, in the boiler system 1, an example has been described in which the processes shown in steps S23 and S24 are performed when an upward DR request signal is received, as shown in step S21 in Fig. 2. However, the processes shown in steps S23 and S24 may be performed at the upward DR start time.

[0082] In the boiler system 1 in the above embodiment, an example has been described in which all of the installed electric boilers and fuel boilers are permitted to operate by the unit count control device, but this is not limiting, and it is also possible that only some of the installed electric boilers and fuel boilers are permitted to operate, with the rest not being permitted to operate and not operating (for example, in the example of FIG. 3, fuel boilers 1 to 5 are permitted to operate, but no. 6 is not permitted to operate, or electric boilers 1 to 6 are permitted to operate, but no. 7 and no. 8 are not permitted to operate). In this case, when the above-mentioned down DR or up DR control is performed, the boilers not permitted to operate may be operated only for that control. 6, an example has been described in which the amount obtained by subtracting the current steam generation rate of the fuel boiler from the maximum steam generation rate of the fuel boiler is set as the upper limit of the amount of steam that can be used for downward DR, but the present invention is not limited to this. Alternatively, the amount obtained by subtracting the maximum steam generation rate of the fuel boiler from the maximum steam generation rate of the fuel boiler that is permitted to operate (i.e., the maximum steam generation rate of the fuel boiler that is not permitted to operate) may be set as the upper limit of the amount of steam that can be used for downward DR. Similarly, as shown in steps S41 to S43 of FIG. 7, an example has been described in which the amount obtained by subtracting the current steam generation rate of the electric boiler from the maximum steam generation rate of the electric boiler is set as the upper limit of the amount of steam that can be used for upward DR, but the present invention is not limited to this. Alternatively, the amount obtained by subtracting the maximum steam generation rate of the electric boiler from the maximum steam generation rate of the electric boiler that is permitted to operate (i.e., the maximum steam generation rate of the electric boiler that is not permitted to operate) may be set as the upper limit of the amount of steam that can be used for upward DR. In the boiler system 1 in the above embodiment, an example has been described in which demand response is performed taking into account the contracted power amount and the amount of power generated within the facility, but this is not limiting, and demand response may be performed taking into account only the contracted power amount without taking into account the amount of power generated within the facility, or demand response may be performed taking into account only the amount of power generated within the facility without taking into account the contracted power amount.

[0083] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0084] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] This disclosure also includes matters that contribute to achieving Goal 12 of the SDGs (Sustainable Development Goals), "Responsible Consumption and Production," and Goal 13, "Take urgent action to combat climate change." [Explanation of symbols]

[0085] 1. Boiler system 2A electric boiler 2B fuel boiler 3 Steam piping 4 Steam header 5 Vapor pressure sensor 6 Signal Line 8A First unit control device 8B First number control device 9 Signal Line 10 Supply pipe 11 Equipment used 12 Power demand monitoring device

Claims

1. A unit number control device for controlling a plurality of boilers including one or more electric boilers and one or more fuel boilers, a steam pressure acquisition unit that acquires steam pressures of steam generated in the plurality of boilers; an electric power information acquisition unit that acquires information about electric power available in the plurality of boilers; a control unit that controls each of the plurality of boilers based on the steam pressure and the power information, The control unit performs combustion state change control to change the combustion state of at least one of the one or more fuel-fired boilers before starting reduction control when reduction control is performed to reduce the amount of steam generated by the one or more electric boilers based on the power information even if the steam pressure is at a value that does not require a change in the combustion state of the boilers.

2. The unit number control device according to claim 1 , wherein the control unit changes the combustion state of the fuel boiler that is not firing to pressure maintenance combustion as the combustion state change control.

3. the one or more fuel-fired boilers include a fuel-fired boiler having a first combustion position and a second combustion position capable of producing a greater amount of steam than the first combustion position; The unit count control device according to claim 1 , wherein the control unit increases the number of fuel-fired boilers whose combustion state is in the first combustion position among the fuel-fired boilers as the combustion state change control.

4. 2. The unit count control device according to claim 1, wherein the control unit specifies the smaller of the differential steam amount between the amount of steam that can be generated by all of the one or more fuel-fired boilers and the amount of steam generated by the fuel boilers that are permitted to operate among the one or more fuel-fired boilers, and the amount of steam generated by the electric boilers that are permitted to operate among the one or more electric boilers, as an upper limit steam amount that can be reduced by the reduction control, and performs the reduction control within the range of the upper limit steam amount.

5. A unit number control device for controlling a plurality of boilers including one or more electric boilers and one or more fuel boilers, a steam pressure acquisition unit that acquires steam pressures of steam generated in the plurality of boilers; an electric power information acquisition unit that acquires information about electric power available in the plurality of boilers; a control unit that controls each of the plurality of boilers based on the steam pressure and the power information, The control unit performs a number control device that, when performing an increase control to increase the amount of steam generated by the one or more electric boilers based on the power information even if the steam pressure is a value that does not require a change in the combustion state of the boiler, performs a decrease control to decrease the amount of steam generated by the one or more combustion boilers at the time the amount of steam generated by the one or more electric boilers increases.

6. 6. The unit number control device according to claim 5, wherein the timing at which the amount of steam generated by the one or more electric boilers increases is the timing at which a pressure in one of the electric boilers reaches or exceeds a predetermined value.

7. 6. The unit count control device according to claim 5, wherein the control means specifies the smaller of the differential steam amount between the amount of steam that can be generated by all of the one or more electric boilers and the amount of steam generated by the electric boilers that are permitted to operate among the one or more electric boilers, and the amount of steam generated by the fuel boilers that are permitted to operate among the one or more fuel-fired boilers as an upper limit steam amount that can be increased by the increase control, and performs the increase control within the range of the upper limit steam amount.

8. The number control device according to claim 1 or claim 5, wherein the power information available for the plurality of boilers is information that specifies not only the power supplied from outside but also the amount of power generated within the facility in which the boilers are installed.

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