Boiler control device, boiler system, and boiler control method

Abstract

According to the present invention, a controller of a boiler comprises: a supply command unit that outputs a first supply command and a second supply command for controlling the operation of a fuel supply unit; and a spray command unit that outputs a first spray command and a second spray command for controlling the operation of a reheater spray. The supply command unit and the spray command unit execute: a first operation that outputs the first supply command for supplying pulverized coal to a furnace and preventing ammonia from being supplied to the furnace, and the first spray command for preventing water from being sprayed from the reheater spray; and a second operation that outputs the second supply command for supplying the pulverized coal to the furnace along with ammonia, and the second spray command for spraying water from the reheater spray.

Description

Boiler control device, boiler system, and boiler control method

[0001] The present disclosure relates to a boiler control device, a boiler system, and a boiler control method.

[0002] Patent Document 1 describes a temperature control method for a co-firing boiler furnace that reduces the amount of feedwater supplied to the furnace. The temperature control method in Patent Document 1 increases the spray amount as the co-firing ratio of fuels with low furnace heat absorption increases. As a result, the outlet steam temperature of the furnace pass can be controlled to a constant value.

[0003] Japanese Patent Application Publication No. 62-276307

[0004] When operating a boiler, it is considered to supply a type of fuel different from the originally planned fuel to the boiler. The combustion results may differ when the originally planned fuel is supplied and when a type of fuel different from the originally planned fuel is supplied. Therefore, the operating conditions of the boiler when the originally planned fuel is supplied may not be suitable for the boiler when a type of fuel different from the originally planned fuel is supplied. It has been desired in the art to expand the operating conditions under which a boiler can continue to operate normally.

[0005] The present disclosure describes a boiler control device, a boiler system, and a boiler control method that can expand the operating conditions under which normal operation is possible.

[0006] A boiler control device according to a first aspect of the present disclosure is a boiler including a superheater and a reheater in which gas generated by burning fuel inside a furnace is diverted at a controllable ratio and heat-exchanges between each of the diverted gases and a heat medium, the furnace being provided with a fuel supply unit that supplies at least one of a first fuel and a second fuel to the furnace, and the reheater being provided with a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing in the reheater, the boiler control device including a first supply command or The system includes a supply command unit that outputs a second supply command, and a spray command unit that outputs a first spray command or a second spray command that controls the operation of the reheater spray, and the supply command unit and the spray command unit execute a first operation of outputting a first supply command that causes a first fuel to be supplied to the furnace and a second fuel not to be supplied to the furnace, and a first spray command that does not cause liquid to be sprayed from the reheater spray, and a second operation of outputting a second supply command that causes the first fuel to be supplied to the furnace and a second fuel to be supplied to the furnace, and a second spray command that causes liquid to be sprayed from the reheater spray.

[0007] A boiler system according to a second aspect of the present disclosure includes a boiler having a superheater and a reheater in which gas generated by burning fuel inside a furnace is diverted at a controllable ratio and heat exchange is performed between each of the diverted gases and a heat medium, and a controller for controlling the operation of the boiler, wherein the boiler has a fuel supply unit that supplies at least one of a first fuel and a second fuel to the furnace, and a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing to the reheater, and the controller issues a first supply command and The fuel supply system includes a supply command unit that outputs a first supply command and a second supply command, and a spray command unit that outputs a first spray command and a second spray command that control the operation of the reheater spray, and the supply command unit and the spray command unit execute a first operation of outputting a first supply command that causes the first fuel to be supplied to the furnace and the second fuel not to be supplied to the furnace, and a first spray command that causes the reheater spray not to spray liquid, and a second operation of outputting a second supply command that causes the first fuel to be supplied to the furnace and the second fuel to be supplied to the furnace, and a second spray command that causes the reheater spray to spray liquid.

[0008] A boiler control method according to a third aspect of the present disclosure is a boiler including a superheater and a reheater in which gas produced by the combustion of fuel inside a furnace is diverted at a controllable rate and heat is exchanged between each of the diverted gases and a heat medium, the furnace being provided with a fuel supply unit that supplies at least one of a first fuel and a second fuel to the furnace, and the reheater being provided with a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing through the reheater, the boiler control method including a first step of outputting a first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and a first spray command to not spray liquid from the reheater spray, and a second step of outputting a second supply command to supply the first fuel to the furnace and also supply the second fuel to the furnace, and a second spray command to spray liquid from the reheater spray.

[0009] In this boiler control device, boiler system, and boiler control method, a transition is made from a state in which the first fuel is supplied to the furnace but the second fuel is not supplied to the furnace and the reheater spray is not spraying liquid to a state in which the first fuel and the second fuel are supplied to the furnace and the reheater spray is spraying liquid. This allows the temperature of the heat transfer medium to be lowered by the reheater spray spraying liquid, making it possible to expand the operating conditions under which normal operation is possible.

[0010] In the boiler control device described above, when the second operation is performed, the spray command unit may output the second spray command simultaneously with the timing at which the supply command unit outputs the second supply command. Also, when the second operation is performed, the spray command unit may output the second spray command after the supply command unit outputs the second supply command. These types of operations also make it possible to expand the operating conditions under which normal operation is possible.

[0011] In the boiler control device, the supply command unit and the spray command unit may further execute a third operation of outputting a first supply command for supplying the first fuel to the furnace and not supplying the second fuel to the furnace, and a second spray command for spraying liquid from the reheater spray. This operation also makes it possible to expand the operating conditions under which normal operation is possible.

[0012] In the boiler control device, the second fuel may be ammonia. In this case, the boiler can reduce carbon-containing substances contained in exhaust gas, thereby reducing the environmental load.

[0013] The boiler control device, boiler system, and boiler control method disclosed herein can expand the operating conditions under which normal operation is possible.

[0014] Figure 1 is a schematic diagram of a boiler system. Figure 2 is a functional block diagram of a control device. Figure 3(a) is a timing chart showing the supply amount of pulverized coal. Figure 3(b) is a timing chart of a signal given to an ammonia supply valve. Figure 3(c) is a timing chart of a signal given to a reheater spray valve. Figure 4 is a flowchart of a boiler control method.

[0015] Hereinafter, a boiler control device, a boiler system, and a boiler control method according to embodiments will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0016] FIG. 1 is a schematic diagram of a boiler system 100. The boiler system 100 includes a boiler 1 and a controller 9 (controller). The boiler system 100 is used as a thermal power generation facility. The boiler 1 includes a furnace 2, a combustion unit 3, a heat exchange unit 5, a reheater gas damper 61, and a superheater gas damper 62. The boiler 1 generates high-temperature gas by burning fuel inside the furnace 2. The boiler 1 performs heat exchange from the high-temperature gas to a heat medium via the heat exchange unit 5.

[0017] The combustion unit 3 has a fuel supply section 31 and a combustion section 32. The fuel supply section 31 can supply multiple fuels. For example, the fuel supply section 31 can supply pulverized coal and ammonia as fuel. The fuel supply section 31 includes a pulverized coal supply section 311 that supplies pulverized coal and an ammonia supply section 312 that supplies ammonia. There are no particular limitations on the specific configurations of the pulverized coal supply section 311 and the ammonia supply section 312, and known mechanisms can be applied. The combustion section 32 is a so-called burner. The combustion unit 3 may include, for example, a burner for burning pulverized coal and a burner for burning ammonia. A state in which the combustion section 32 burns only pulverized coal is referred to as "single-fuel combustion." A state in which the combustion section 32 burns pulverized coal and ammonia is referred to as "mixed combustion."

[0018] The pulverized coal supply unit 311 has a function of supplying pulverized coal and a function of stopping the supply of pulverized coal. Furthermore, the pulverized coal supply unit 311 may have a function of outputting information indicating the state of the supply of pulverized coal. The ammonia supply unit 312 has a function of supplying ammonia and a function of stopping the supply of ammonia. Furthermore, the ammonia supply unit 312 may have a function of outputting information indicating the state of the supply of ammonia.

[0019] The furnace 2 of this embodiment employs a so-called parallel path system. The flow path of the parallel path furnace 2 is divided into two flow paths downstream of the furnace: a superheater path P52 and a reheater path P51. The heat absorption capacity of the horizontal reheater 51 is increased or decreased by adjusting the flow rates of gas passing through the superheater path P52 and the reheater path P51. As a result, the reheat steam temperature can be controlled.

[0020] The parallel-path furnace 2 has the function of diverting high-temperature gas generated by the combustion of fuel inside the furnace 2 at a controllable ratio. The furnace 2 is formed with a reheater path P51 and a superheater path P52. The reheater path P51 is provided with a horizontal reheater 51 and a reheater gas damper 61. The superheater path P52 is provided with a horizontal superheater 52 and a superheater gas damper 62. By controlling the reheater gas damper 61, the high-temperature gas can be diverted to the reheater path P51 and the superheater path P52 at a predetermined ratio. The reheater gas damper 61 adjusts the flow rate of gas passing through the reheater path P51 and the superheater path P52. When the heat absorption amount required by the horizontal reheater 51 installed in the reheater path P51 decreases, the reheater gas damper 61 is adjusted in the throttling direction. However, it becomes difficult to control the reheat steam temperature if the reheat gas damper 61 cannot be fully throttled. When the reheat steam temperature exceeds the control range and rises above the set value, the reheat steam temperature is controlled to the set value by injecting the reheater spray 511.

[0021] The heat exchange unit 5 has a horizontal reheater 51 arranged in the reheater pass P51 and a horizontal superheater 52 arranged in the superheater pass P52. The heat exchange unit 5 may include at least one of a reheater and a superheater arranged in another location inside the furnace 2. The heat exchange unit 5 may include a coal economizer 55 as a component. For example, the coal economizer 55 may be arranged downstream of the horizontal reheater 51 and the horizontal superheater 52.

[0022] The heat medium flow path 7 sends out the heat medium from the furnace 2 to the power generation facility 8 and also sends the heat medium from the power generation facility 8 to the furnace 2. Steam flows through the heat medium flow path 7 as a heat medium. A portion of the heat medium flow path 7 passes through a horizontal reheater 51. Reheater sprays 511 are provided inside the heat medium flow path 7 that passes through the horizontal reheater 51. When water is sprayed from the reheater sprays 511, the temperature of the steam flowing inside the heat medium flow path 7 decreases. The reheater sprays 511 are used to control the temperature of the steam flowing inside the heat medium flow path 7.

[0023] The controller 9 controls the operation of the boiler 1. The controller 9 has a CPU (Central Processing Unit) that is a processor 91, a memory 92, an input port 93, and an output port 94.

[0024] The processor 91 executes an operating system, application programs, etc. The processor 91 executes the operating system, application programs, etc., thereby realizing the functional blocks shown in FIG. 2 . The memory 92 stores the operating system, application programs, etc. Furthermore, the memory 92 stores some data required for controlling the boiler 1. The input device 203 accepts input operations from an operator of the boiler 1. For example, the input device 203 may accept manual operations of the boiler 1 by the operator. Specifically, the input device 203 may accept an operation by the operator to start supplying the second fuel.

[0025] The input port 93 and the output port 94 may be physical connectors or communication interfaces such as a network card or a wireless communication module. The input port 93 may accept temperature data and a control signal from the input device 203. The output port 94 sends supply signals C311 and C312 to the fuel supply unit 31, etc. The controller 9 includes a supply command unit 911, a gas damper command unit 912, and a spray command unit 913. The supply command unit 911, the gas damper command unit 912, and the spray command unit 913 are functional components of the controller 9.

[0026] The supply command unit 911 controls the operation of the fuel supply unit 31. For example, the supply command unit 911 receives an operation command from the input device 203. The supply command unit 911 generates supply signals C311 and C312 based on the operation command. The supply command unit 911 outputs the generated supply signals C311 and C312.

[0027] The supply signal C311 controls the operation of the pulverized coal supply unit 311. The supply signal C311 instructs the start and stop of the supply of pulverized coal. The supply signal C311 may also instruct the amount of pulverized coal to be supplied. The supply signal C312 controls the operation of the ammonia supply unit 312. The supply signal C312 instructs the start and stop of the supply of ammonia. The supply signal C312 may also instruct the amount of ammonia to be supplied.

[0028] The gas damper command unit 912 controls the operation of the reheater gas damper 61. The gas damper command unit 912 controls the gas diversion ratio, for example, in accordance with the gas temperature. The gas damper command unit 912 receives temperature data from a temperature sensor provided in the reheater. The gas damper command unit 912 generates a control signal C61 for the reheater gas damper 61 based on the temperature data. The control signal C61 indicates the opening degree of the reheater gas damper 61.

[0029] The spray command unit 913 controls the operation of the reheater sprays 511. The spray command unit 913 determines whether to inject water from the reheater sprays 511 depending on whether ammonia combustion is occurring. For example, the spray command unit 913 generates a signal C511s including an instruction to start injecting water from the reheater sprays 511 in response to a supply signal C312 including an instruction to "start the supply of ammonia." The spray command unit 913 may generate a signal C511s including an instruction to start injecting water from the reheater sprays 511 in response to measurement data indicating that the supply of ammonia has been performed. The spray command unit 913 outputs a spray signal C511 to the reheater sprays 511 including either an instruction to start injecting water from the reheater sprays 511 or an instruction to stop injecting water from the reheater sprays 511.

[0030] The controller 9 executes a single-fuel combustion start operation (first operation), a single-fuel combustion continuation operation, a dual-fuel combustion start operation (second operation), and a dual-fuel combustion end operation.

[0031] When the exclusive-fuel combustion start operation is in progress, the supply command unit 911 outputs a supply command CS1 (first supply command). The supply command CS1 includes a supply signal C311s that causes pulverized coal to be supplied to the furnace 2, and a supply signal C312e that causes ammonia not to be supplied to the furnace 2. When the exclusive-fuel combustion start operation is in progress, the spray command unit 913 outputs a spray command CP1 (first spray command). The spray command CP1 (see FIG. 3(c)) includes a spray signal C511e that causes water not to be sprayed from the reheater spray 511.

[0032] When the continuous single-fuel combustion operation is in progress, the supply command unit 911 outputs a supply command CS2. The supply command CS2 includes a supply signal C311t that continues the supply of pulverized coal and a supply signal C312e that prevents ammonia from being supplied to the furnace 2. When the continuous single-fuel combustion operation is in progress, the spray command unit 913 outputs a spray command CP2. The spray command CP2 includes a spray signal C511e that prevents water from being sprayed from the reheater spray 511.

[0033] When the mixed combustion start operation is in progress, the supply command unit 911 outputs a supply command CS3 (second supply command). The supply command CS3 includes a supply signal C311t for continuing the supply of pulverized coal and a supply signal C312s for supplying ammonia to the furnace 2. When the mixed combustion start operation is in progress, the spray command unit 913 outputs a spray command CP3 (second spray command). The spray command CP3 includes a spray signal C511s for spraying water from the reheater spray 511.

[0034] When mixed combustion is stopped, the supply command unit 911 outputs a supply command CS4. The supply command CS4 includes a supply signal C311t that continues the supply of pulverized coal and a supply signal C312e that prevents ammonia from being supplied to the furnace 2. When mixed combustion is stopped, the spray command unit 913 outputs a spray command CP4. The spray command CP4 includes a spray signal C511e that prevents water from being sprayed from the reheater spray 511.

[0035] <Boiler Control Method> Next, the operation of the boiler system 100 including the controller 9 will be described with reference to Fig. 4. That is, the method for controlling the boiler 1 will be described. Fig. 4 is a flowchart of the boiler control method.

[0036] First, the supply of pulverized coal is started (step S1). The controller 9 executes the mono-fuel combustion start operation (first operation). When the mono-fuel combustion start operation is performed, the controller 9 outputs the supply command CS1 and the spray command CP1. The details of the supply command CS1 and the spray command CP1 are as described above.

[0037] Next, the combustion of pulverized coal is continued (step S2). The controller 9 executes the continuous mono-fuel combustion operation. When the continuous mono-fuel combustion operation is in progress, the controller 9 outputs the supply command CS2 and the spray command CP2. The details of the supply command CS2 and the spray command CP2 are as described above.

[0038] When in the single-fuel state, the controller 9 may inject water from the reheater spray 511 as needed (third operation).

[0039] Next, the spray command unit 913 determines whether to start supplying ammonia (step S3). The spray command unit 913 determines whether to transition from the mono-fuel combustion state to the multi-fuel combustion state. The spray command unit 913 may make this determination based on the operation plan of the boiler system 100, or may decide to transition to the multi-fuel combustion state in accordance with the operation of the operator of the boiler system 100. Furthermore, the spray command unit 913 may determine the start of the multi-fuel combustion operation based on the supply signal C312s.

[0040] When the controller 9 determines that it is not time to start ammonia combustion (step S3: NO), the controller 9 maintains the mono-fuel combustion state in which only pulverized coal is burned. When the controller 9 determines that it is time to start ammonia combustion (step S3: YES), the controller 9 executes a mixed-fuel combustion start operation (second operation). When the mixed-fuel combustion start operation is performed, the controller 9 outputs a supply command CS3 and a spray command CP3. The details of the supply command CS3 and the spray command CP3 are as described above. As a result of the output of the spray command CP3, water starts to be sprayed from the reheater spray 511. Therefore, the temperature of the steam flowing through the heat medium flow path 7 located inside the horizontal reheater 51 decreases.

[0041] There are several possible modes for the timing at which the reheater spray 511 starts spraying water and the timing at which the ammonia combustion starts. First, the timing at which the reheater spray 511 starts spraying water may be simultaneous with the timing at which the ammonia combustion starts. For example, the first mode can be used in cases where the determination is based on an operation plan and a determination is based on the supply signal C312s. Second, the timing at which the reheater spray 511 starts spraying water may be before the ammonia combustion starts. For example, the second mode can be used in cases where the determination is based on an operation plan. Third, the timing at which the reheater spray 511 starts spraying water may be after the ammonia combustion starts. For example, the third mode can be used in cases where the supply of ammonia is detected by a sensor.

[0042] Next, it is determined whether or not to stop the supply of ammonia (step S6). This operation is executed by the controller 9. The controller 9 may determine the timing to stop the supply of ammonia based on, for example, an operation plan of the boiler system 100. If it is determined not to stop the supply of ammonia (step S6: NO), the mixed combustion operation is continued.

[0043] If it is determined that the supply of ammonia should be stopped (step S6: YES), the controller 9 executes the mixed combustion termination operation. When the mixed combustion termination operation is executed, the controller 9 outputs the supply command CS4 and the spray command CP4. The details of the supply command CS4 and the spray command CP4 are as described above.

[0044] [Effects] Existing coal-fired boilers that use a reheater gas damper 61 to control reheat steam temperature are being considered for co-firing with a fuel other than coal (e.g., ammonia). In the case of co-firing, the fuel switch can cause changes in heat absorption characteristics. The amount of exhaust gas can also increase. These factors can make it difficult to control the reheater steam temperature using the reheater gas damper 61. During coal-fired mono-fuel operation, the reheat steam temperature is controlled by the reheater gas damper 61. Temperature control using the reheater spray 511 is used as a backup function in case it becomes difficult to control the reheater steam temperature using the reheater gas damper 61. However, depending on the fuel being co-fired, there may be situations in which the reheater spray 511 is used as the primary temperature control.

[0045] The boiler system 100 includes a boiler 1 having a horizontal superheater 52 and a horizontal reheater 51 in which gas produced by burning fuel inside a furnace 2 is diverted at a controllable ratio and heat exchange between each of the diverted gases and a heat medium is performed between each of the diverted gases and the heat medium, and a controller 9 for controlling the operation of the boiler 1. The boiler 1 includes a fuel supply unit 31 that supplies pulverized coal and ammonia to the furnace 2, and a reheater spray 511 that sprays a liquid to lower the temperature of the heat medium flowing into the horizontal reheater 51. The controller 9 includes a supply command unit 911 that outputs a first supply command and a second supply command that control the operation of the fuel supply unit 31, and a spray command unit 913 that outputs a first spray command and a second spray command that control the operation of the reheater spray. The supply command unit 911 and the spray command unit 913 execute a first operation of outputting a first supply command to supply pulverized coal to the furnace 2 while not supplying ammonia to the furnace 2 and a first spray command to not spray water from the reheater spray 511, and a second operation of outputting a second supply command to supply pulverized coal to the furnace 2 while also supplying ammonia to the furnace 2 and a second spray command to spray water from the reheater spray 511.

[0046] The boiler control method includes a first step S1 of outputting a first supply command to supply pulverized coal to the furnace 2 while not supplying ammonia to the furnace 2 and a first spray command to not spray water from the reheater spray 511, and second steps S4 and S5 of outputting a second supply command to supply pulverized coal to the furnace 2 while also supplying ammonia to the furnace 2 and a second spray command to spray water from the reheater spray 511.

[0047] The controller 9 of the boiler 1, the boiler system 100, and the boiler control method transition from a state in which pulverized coal is supplied to the furnace 2, ammonia is not supplied to the furnace 2, and the reheater spray 511 is not spraying water, to a state in which pulverized coal and ammonia are supplied to the furnace 2, and the reheater spray 511 sprays water. This causes the reheater spray 511 to spray water, which lowers the temperature of the heat medium, making it possible to expand the operating conditions under which normal operation is possible.

[0048] [Modifications] The boiler control device, boiler system, and boiler control method of the present disclosure are not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0049] In the above embodiment, pulverized coal is used as an example of the first fuel. Another example of the first fuel is a so-called gray carbon fuel. For example, the first fuel may be heavy oil, natural gas, or the like.

[0050] In the above-described embodiment, ammonia is supplied as the second fuel to the furnace 2. However, biomass fuel may be supplied as the second fuel to the furnace 2. Furthermore, both ammonia and biomass fuel may be supplied as the second fuel to the furnace 2.

[0051] Boilers are classified according to their water circulation type, combustion type, ventilation type, etc., but the boiler control device, boiler system, and boiler control method disclosed herein can be applied to boilers that use a parallel path type in the rear heat transfer section.

[0052] The boiler control device, boiler system, and boiler control method disclosed herein can expand the operating conditions under which normal operation is possible. This effect allows for the production of clean energy, namely, electric power. As a result, the boiler control device, boiler system, and boiler control method disclosed herein contribute to Target 7.3 and Target 7.a of the United Nations' Sustainable Development Goals (SDGs).

[0053] Target 7.3 is to "double the global rate of improvement in energy efficiency by 2030."

[0054] Target 7.a is "By 2030, enhance international cooperation to facilitate access to clean energy research and technology, including renewable energy, energy efficiency and advanced and cleaner fossil-fuel technology, and promote investment in energy infrastructure and clean energy technology."

[0055] [Additional Notes] The present disclosure includes the following configurations.

[0056] The present disclosure provides a boiler control device comprising: a superheater and a reheater in which gas generated by the combustion of fuel inside a furnace is diverted at a controllable ratio, and heat is exchanged between each of the diverted gases and a heat medium; the furnace is provided with a fuel supply unit that supplies at least one of a first fuel and a second fuel as the fuel to the furnace; and the reheater is provided with a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing through the reheater; the boiler control device comprises: a supply command unit that outputs a first supply command or a second supply command that controls the operation of the fuel supply unit; and a spray command unit that outputs a first spray command or a second spray command that controls the operation of the reheater spray; the supply command unit and the spray command unit are configured to: and a second operation of outputting the second supply command to supply the first fuel to the furnace and the second fuel to the furnace, and the second spray command to spray liquid from the reheater spray.

[0057] The present disclosure is [2] "A boiler control device as described in the above [1], wherein, when the second operation is performed, the spray command unit outputs the second spray command at the same time as the supply command unit outputs the second supply command."

[0058] The present disclosure is [3] "A boiler control device as described in the above [1], wherein when the second operation is performed, the spray command unit outputs the second spray command after the supply command unit outputs the second supply command."

[0059] The present disclosure is [4] "A boiler control device described in the above [1] or [2], wherein the supply command unit and the spray command unit further execute a third operation of outputting the first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and a second spray command to spray liquid from the reheater spray."

[0060] The present disclosure is [5] "A boiler control device according to any one of [1] to [4] above, wherein the second fuel is ammonia."

[0061] The present disclosure is [6] a boiler including a superheater and a reheater in which gas generated by the combustion of fuel inside a furnace is diverted at a controllable ratio and heat exchanged between each of the diverted gases and a heat medium; and a controller for controlling the operation of the boiler, wherein the boiler has a fuel supply unit that supplies at least one of a first fuel and a second fuel as the fuel to the furnace, and a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing in the reheater, the controller has: a supply command unit that outputs a first supply command and a second supply command that control the operation of the fuel supply unit; and a spray command unit that outputs a first spray command and a second spray command that control the operation of the reheater spray, the supply command unit and the spray command unit being: a first operation that outputs the first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and the first spray command to not spray a liquid from the reheater spray; and a second operation of outputting the second supply command to supply the first fuel to the furnace and the second fuel to the furnace, and the second spray command to spray liquid from the reheater spray.

[0062] The present disclosure is [7] "A boiler including a superheater and a reheater in which gas generated by the combustion of fuel inside a furnace is diverted at a controllable ratio and heat exchange is performed between each of the diverted gases and a heat medium, wherein the furnace is provided with a fuel supply unit that supplies at least one of a first fuel and a second fuel to the furnace as the fuel, and the reheater is provided with a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing in the reheater, the boiler control method including: a first step of outputting a first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and a first spray command to not spray liquid from the reheater spray; and a second step of outputting a second supply command to supply the first fuel to the furnace and also supply the second fuel to the furnace, and a second spray command to spray liquid from the reheater spray."

[0063] REFERENCE SIGNS LIST 1 Boiler 2 Furnace 51 Horizontal reheater 511 Reheater spray 52 Horizontal superheater P51 Reheater path P52 Superheater path 61 Reheater gas damper 62 Superheater gas damper 9 Controller 911 Supply command unit 912 Gas damper command unit 913 Spray command unit 31 Fuel supply unit 100 Boiler system CP1 Spray command (first spray command) CP3 Spray command (second spray command) CS1 Supply command (first supply command) CS3 Supply command (second supply command)

Claims

1. A boiler comprising a superheater and a reheater in which gas generated by the combustion of fuel inside a furnace is diverted at a controllable rate and heat is exchanged between each of the diverted gases and a heat medium, wherein the furnace is provided with a fuel supply unit that supplies at least one of a first fuel and a second fuel to the furnace as the fuel, and the reheater is provided with a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing through the reheater, a control device for the boiler comprising: a supply command unit that outputs a first supply command or a second supply command that controls the operation of the fuel supply unit; and a spray command unit that outputs a first spray command or a second spray command that controls the operation of the reheater spray, wherein the supply command unit and the spray command unit perform: a first operation that outputs the first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and the first spray command that does not cause the reheater spray to spray liquid; a second operation of outputting the second supply command to supply the first fuel to the furnace and the second fuel to the furnace, and the second spray command to spray liquid from the reheater spray.

2. A boiler control device as described in claim 1, wherein when performing the second operation, the spray command unit outputs the second spray command at the same time as the supply command unit outputs the second supply command.

3. A boiler control device as described in claim 1, wherein when performing the second operation, the spray command unit outputs the second spray command after the supply command unit outputs the second supply command.

4. The boiler control device described in claim 1, wherein the supply command unit and the spray command unit further perform a third operation of outputting the first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and the second spray command to spray liquid from the reheater spray.

5. The boiler control device according to claim 1, wherein the second fuel is ammonia.

6. A boiler comprising: a superheater and a reheater in which gas generated by the combustion of fuel inside a furnace is diverted at a controllable rate, and which exchanges heat with a heat medium between each of the diverted gases; and a controller for controlling the operation of the boiler, wherein the boiler has a fuel supply unit that supplies at least one of a first fuel and a second fuel as the fuel to the furnace, and a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing into the reheater, and the controller has: a supply command unit that outputs a first supply command and a second supply command that control the operation of the fuel supply unit; and a spray command unit that outputs a first spray command and a second spray command that control the operation of the reheater spray, wherein the supply command unit and the spray command unit perform: a first operation that outputs the first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and the first spray command to not spray a liquid from the reheater spray; a second operation of outputting the second supply command to supply the first fuel to the furnace and the second fuel to the furnace, and the second spray command to spray liquid from the reheater spray.

7. A boiler having a superheater and a reheater in which gases produced by the combustion of fuel inside a furnace are diverted at a controllable rate and heat is exchanged between each of the diverted gases and a heat medium, wherein the furnace is provided with a fuel supply unit that supplies at least one of a first fuel and a second fuel to the furnace as the fuel, and the reheater is provided with a reheater spray that sprays a liquid to lower the temperature of the heat medium flowing through the reheater, the boiler control method comprising: a first step of outputting a first supply command to supply the first fuel to the furnace and not supply the second fuel to the furnace, and a first spray command to not spray liquid from the reheater spray; and a second step of outputting a second supply command to supply the first fuel to the furnace and also supply the second fuel to the furnace, and a second spray command to spray liquid from the reheater spray.

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