JP2017166714A - Steam super-heating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam super-heating system capable of adapting freely for a variation of super-heated steam and capable of effectively restricting an increased cost even if a required amount of super-heated steam is large.SOLUTION: A steam super-heating system 1 comprises several fuel burned type heaters 20; several fuel burned type flow rate adjustment valves 21 constituted to enable a path of fuel burned type steam supply line L20 to be opened or closed; an electric heater 30; an electric flow rate adjustment valve 31 arranged at the electric steam supply line L30 and constituted to enable a flow rate to be adjusted; a control part 80; and a memory part 85. The control part 80 performs a controlling operation for combustion for a fuel burned type heater 20 set at a unit number setting part 82 and a controlling to make an opened state of the fuel burned type flow rate adjustment valve 21 corresponding to the fuel burned type heater 20 and controls a flow rate of the electric flow rate adjustment valve 31 and a super-heating at the electric heater 30 on the basis of a difference between required necessary super-heated steam amount and a total supplied super-heated steam amount of the fuel burned type heater 20 as an object to be controlled for super-heated state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steam superheating system that superheats steam and supplies superheated steam.

  2. Description of the Related Art Conventionally, in a steam superheating system that superheats steam supplied from a steam generator such as a boiler and supplies superheated steam, a configuration for adjusting the superheat degree and supply amount of superheated steam is known. Patent Documents 1 to 3 disclose such a steam superheating system. Patent Document 1 discloses a configuration in which the amount of superheated steam generated is adjusted by adjusting the burner combustion amount. Patent Document 2 discloses a configuration for controlling the degree of superheat of steam to a predetermined degree of superheat based on a parameter related to the degree of dryness of steam. Patent Document 3 discloses a configuration in which superheated steam superheated by a superheater is supplied to a supply destination, and steam supplied to another supply destination is superheated by a part of the superheated steam.

JP 2008-32235 A JP 2014-55694 A JP 2014-55695 A

  By the way, the electric steam superheater is superior to the fuel steam superheater using a burner in that it can cope with fluctuations in the flow rate and temperature of the superheated steam. However, since the electric steam superheater increases the electric capacity as the amount of superheated steam required for the load device increases, the cost increases. Since the configuration disclosed in Patent Document 1 employs a configuration in which steam is superheated using exhaust gas from a boiler and superheated steam is supplied to the load equipment side, the temperature of the superheated steam depends on the temperature of the exhaust gas. It will be. Therefore, there is room for improvement from the viewpoint of accurately controlling the flow rate of superheated steam at a predetermined temperature. In this regard, in the configuration disclosed in Patent Document 2, although accurate control is performed in accordance with the degree of dryness of steam, an electric steam superheater is used in a steam superheat system that requires a large amount of superheated steam required for load equipment. If is used, the electric capacity becomes large. In the configuration disclosed in Patent Document 3, a plurality of steam superheaters are used, but the steam supply destination is different. Similar to the prior art, when the amount of superheated steam required for the load equipment is large, there is room for improvement in terms of reducing costs while accommodating fluctuations in superheated steam.

  An object of the present invention is to provide a steam superheating system that can flexibly cope with fluctuations in superheated steam even when the amount of superheated steam required is large and can effectively suppress an increase in cost.

  The present invention is a steam superheating system that superheats steam to supply superheated steam, and includes a plurality of fuel-type steam superheaters that superheat steam, and a plurality of fuel-type steam superheaters that supply steam to each of the fuel-type steam superheaters. A plurality of first control valves which are arranged in each of the one steam supply line and the plurality of first steam supply lines and configured to be able to open and close the path of the first steam supply line; and electric steam which superheats the steam A superheater, a second steam supply line for supplying steam to the electric steam superheater, a second control valve arranged in the second steam supply line and configured to allow flow rate adjustment, and required required superheat A control unit that controls the fuel-type steam superheater and the electric steam superheater based on a steam amount; and a storage unit that stores a supply superheated steam amount set in each of the fuel-type steam superheaters. The above The control unit sets the number of fuel-type steam superheaters so that the total amount of superheated steam supplied by the fuel-type steam superheater to be superheated control does not exceed the range of the required superheated steam quantity. A fuel-type superheat control unit configured to perform combustion control of the fuel-type steam superheater set in the number setting unit and control to open the first control valve corresponding to the fuel-type steam superheater, The present invention relates to a steam superheating system having an electric superheat control unit that controls the flow rate of the second control valve and the superheat of the electric steam superheater based on the difference between the required superheated steam amount and the total supply superheated steam amount.

  It is preferable that the electric superheat control unit adjusts the flow rate of the second control valve following the change in the required superheated steam amount.

  The steam superheating system includes a flow rate detection unit that detects a flow rate of superheated steam supplied by the steam superheating system, and the control unit needs to set a required superheated steam amount based on a measurement value of the flow rate detection unit. It is preferable to have a superheated steam amount setting part.

  According to the steam superheating system of the present invention, even when the required amount of superheated steam is large, it is possible to flexibly cope with fluctuations in superheated steam and effectively suppress an increase in cost.

It is the figure which showed typically the structure of the steam superheating system which concerns on one Embodiment of this invention. It is a functional block diagram of the control apparatus of this embodiment.

  Hereinafter, a preferred embodiment of the steam superheating system of the present invention will be described with reference to the drawings. The steam superheating system of this embodiment is a system that superheats steam supplied from a steam generator such as a boiler (not shown) and supplies superheated steam to a load device (not shown). The “line” in the present specification is a general term for lines capable of flowing a fluid such as a flow path, a path, and a pipeline.

  FIG. 1 is a diagram schematically showing a configuration of a steam superheating system 1 according to an embodiment of the present invention. As shown in FIG. 1, the steam superheating system 1 of the present embodiment includes a plurality of fuel heaters (fuel steam superheater) 20, a plurality of fuel type flow rate adjustment valves (first control valves) 21, Type heater (electric steam superheater) 30, electric side flow rate adjustment valve (second control valve) 31, flow meter (flow rate detection unit) 50, and control device 70.

  In addition, the steam superheating system 1 of the present embodiment includes a main steam supply line L10, a plurality of fuel-type steam supply lines (first steam supply lines) L20, and an electric-type steam supply line (second steam supply line). L30, a superheated steam line L40, and a superheated steam collecting line L50 are provided as main lines.

  The upstream side of the main steam supply line L10 is connected to a steam header (not shown). Saturated steam generated by a steam generator such as a boiler is gathered in the steam header, and saturated steam (steam) is supplied to the steam superheating system 1 through the steam header and the main steam supply line L10. The main steam supply line L10 is branched at its downstream end into a plurality of fuel-type steam supply lines L20 and an electric-type steam supply line L30.

  Each configuration of the steam superheating system 1 will be described. The fuel heater 20 is a fuel steam superheater that superheats saturated steam by burning a burner. In the present embodiment, a plurality of fuel heaters 20 are arranged in parallel, and fuel gas is supplied to each of the fuel heaters 20. The fuel heater 20 is electrically connected to the control device 70, and overheating of saturated steam by the fuel heater 20 is controlled by a control signal from the control device 70.

  The saturated steam that is the target of overheating of the fuel type heater 20 is supplied to the fuel type heater 20 through the fuel type steam supply line L20. The fuel-type side steam supply line L20 branched from the main steam supply line L10 is connected to each of the plurality of fuel-type heaters 20. The saturated steam sent from the main steam supply line L10 is supplied to each fuel type heater 20 via the fuel type side steam supply line L20.

  The fuel type flow rate adjusting valve 21 is disposed in each of the fuel type side steam supply lines L20. The fuel-type flow rate adjustment valve 21 is a motor valve capable of adjusting the flow rate, and is electrically connected to the control device 70. The opening degree of the fuel type flow rate adjustment valve 21 is controlled by a control signal from the control device 70.

  In the present embodiment, the fuel heater 20 is operated in either a state where the saturated steam is heated (ON state) or a state where the saturated steam is not overheated (OFF). That is, the burner combustion is an ON / OFF operation.

  The fuel-type flow rate adjustment valve 21 is controlled to an open state that is fixed at a predetermined opening degree that is set in advance when the overheating of the fuel-type heater 20 reaches a steady state. The predetermined opening is an opening that can supply the amount of saturated steam necessary for the fuel heater 20. Therefore, in a steady state, a substantially constant amount of saturated steam is supplied to the fuel heater 20.

  In the present embodiment, the opening degree of the fuel-type flow rate adjustment valve 21 is controlled so that the saturated steam flow rate gradually increases when the fuel heater 20 is started, and the flow rate is gradually reduced when the fuel heater 20 is stopped. The opening degree of the fuel-type side flow rate adjustment valve 21 is controlled so as to decrease. As described above, the fuel-type flow rate adjustment valve 21 functions as a flow rate adjustment valve that is controlled so as to continuously change the flow rate when the fuel heater 20 is started and stopped. Further, since the fuel type flow rate adjustment valve 21 is switched to the open state or the closed state in accordance with the overheat control of the fuel type heater 20, it also functions as an on-off valve provided in the saturated steam supply path. In the following description, the open state of the fuel side flow rate adjusting valve 21 indicates a state in which the fuel heater 20 is controlled to a predetermined opening when the overheating of the fuel type heater 20 reaches a steady state.

  The electric heater 30 will be described. The electric heater 30 is an electric steam superheater that superheats saturated steam by electricity. The electric heater 30 is electrically connected to the control device 70, and overheating of saturated steam by the electric heater is controlled by a control signal from the control device 70.

  In the present embodiment, the electric heater 30 superheats the saturated steam by proportional control. That is, overheating control of the electric heater 30 is performed according to the amount of superheated steam requested from the control device 70. In addition, the superheating method of the electric heater 30 may change the superheating degree continuously, or may change the superheating degree step by step.

  The saturated steam that is the target of overheating of the electric heater 30 is supplied to the electric heater 30 through the electric side steam supply line L30. The electric steam supply line L30 branched from the main steam supply line L10 is connected to the electric heater 30. The saturated steam sent from the main steam supply line L10 is supplied to the electric heater 30 through the electric side steam supply line L30.

  The electric side flow rate adjustment valve 31 is disposed in the electric side steam supply line L30. The electric side steam supply line L30 is a motor valve whose flow rate can be adjusted, and is electrically connected to the control device 70. The opening degree of the electric side flow rate adjustment valve 31 is controlled by a control signal from the control device 70. The opening degree of the electric side flow rate adjustment valve 31 is adjusted according to the amount of superheated steam requested from the control device 70. Therefore, the amount of saturated steam supplied to the electric heater 30 is adjusted as appropriate, unlike the steady-state fuel heater 20.

  A superheated steam line L40 is connected to each of the plurality of fuel heaters 20 and the electric heater 30. Each of the superheated steam lines L40 is connected to the superheated steam collecting line L50. The superheated steam superheated by the plurality of fuel heaters 20 and the superheated steam superheated by the electric heater 30 gather at the superheated steam collecting line L50 through the superheated steam line L40, and the superheated steam supply destination It is sent to a load device (not shown).

  The flow meter 50 is provided in the superheated steam collecting line L50. The flow meter 50 detects the flow rate of superheated steam passing through the superheated steam collecting line L50. The flow meter 50 is electrically connected to the control device 70, and the measurement value of the flow meter 50 is transmitted to the control device 70.

  The control device 70 will be described. The control device 70 is a computer that performs various controls of the steam superheating system 1. Next, details of the control device 70 will be described. FIG. 2 is a functional block diagram of the control device 70 of the present embodiment.

  The control device 70 includes a control unit 80 that executes various types of control based on signals from various types of sensors and operation units (all not shown), and a storage that stores programs executed by the control unit 80 and various types of information. Part 85 as a main component.

  A configuration related to overheating control of the fuel heater 20 and the electric heater 30 in the control unit 80 will be described. The control unit 80 includes a necessary superheated steam amount setting unit 81, a number setting unit 82, a fuel-type overheat control unit 83, and an electric overheat control unit 84.

  The required superheated steam amount setting unit 81 sets a required superheated steam amount that is a supply amount of superheated steam supplied by the entire steam superheat system 1. The required superheated steam amount is set based on the required superheated steam amount required from the load device side and the measured value of the flow meter 50. The required amount of superheated steam in the present embodiment is a value having a predetermined range. The necessary superheated steam amount setting unit 81 monitors the flow meter 50 and resets the necessary superheated steam amount at an appropriate timing when the supply amount fluctuates.

  The number setting unit 82 sets the number of fuel heaters 20 to be subjected to overheat control. The number setting unit 82 of the present embodiment is a target for superheat control based on the supplied superheated steam amount set in each of the fuel heaters 20 and the required superheated steam amount set in the required superheated steam amount setting unit 81. The number of the fuel heaters 20 is set.

  The supplied superheated steam amount is the amount of superheated steam supplied from one fuel heater 20 that is superheated in a steady state. That is, the amount of superheated steam supplied from the fuel type heater 20 in a state where the fuel type flow rate adjustment valve 21 is controlled to be in the open state. In the present embodiment, the supplied superheated steam amount of each fuel heater 20 is set to the same value. For example, consider a case where the amount of superheated steam supplied to one fuel heater 20 is 1000 kg / h. Here, when the four fuel heaters 20 are subjected to overheat control, the corresponding fuel type flow rate adjustment valves 21 are controlled to be in the open state, and therefore, the amount of superheated steam of 4000 kg / h is 4 in the steady state. It can be considered that the fuel is supplied from the fuel heater 20 of the stand.

  The number setting unit 82 sets the number of fuel heaters 20 so that the total supplied superheated steam amount, which is the sum of the supplied superheated steam amounts, does not exceed the range of the required superheated steam amount. For example, when the required superheated steam amount is set to a predetermined range based on 3500 kg / h, the superheat control target is set to 3 units, and the total supplied superheated steam amount is set so as not to exceed the required superheated steam amount. It is.

  In the storage unit 85 of the present embodiment, information related to the priority order is stored in addition to the supplied superheated steam amount, and the fuel heater 20 to be superheated controlled is set according to this priority order. In the above example, of the four units, one fuel type heater 20 is not the target of overheat control, but the fuel type heater 20 having the lowest priority is one unit. In addition, the numerical value regarding said superheated steam amount is an illustration, and an appropriate numerical value is set according to the use conditions, such as the steam superheating system 1 and a load apparatus.

  The fuel type overheat control unit 83 controls the fuel type heater 20 and the fuel type flow rate adjusting valve 21 corresponding to the fuel type heater 20. In the present embodiment, combustion control of the burner of the fuel heater 20 set as a target for overheat control by the number setting unit 82 and control of the fuel type flow rate adjustment valve 21 corresponding to the fuel heater 20 are performed. The fuel-type overheat control unit 83 controls combustion stop for the fuel-type heater 20 that is not the target of overheat control, and closes the fuel-type flow rate adjustment valve 21 corresponding to the fuel-type heater 20. To control.

  As described above, the combustion of the fuel heater 20 is ON / OFF operation, and the opening degree of the fuel type flow rate adjustment valve 21 is fixed to a predetermined opening degree in a steady state. Therefore, a certain amount of saturated steam is supplied to the fuel heater 20. Therefore, the amount of superheated steam supplied from the fuel heater 20 (supplied superheated steam amount) is also constant. When there are a plurality of fuel heaters 20 subject to superheat control, the amount of superheated steam (total amount of supplied superheated steam) for the plurality of units is supplied to the load device side through the superheated steam collecting line L50.

  In the present embodiment, the burner combustion of the fuel heater 20 that is subject to overheat control is appropriately turned ON / OFF during overheat control in order to adjust the temperature of the superheated steam supplied to the load device. The temperature of the superheated steam is obtained by measuring the temperature of a superheated steam header (not shown) to which the superheated steam collecting line L50 is connected. Even when the fuel in the burner of the fuel heater 20 that is the target of overheat control is turned off, the fuel type flow rate adjustment valve 21 remains open. As described above, the fuel type flow rate adjustment valve 21 of the fuel type heater 20 that is not set in the number setting unit 82 as a target for overheat control is controlled to be closed and whether or not it is a target for overheat control. The control of the fuel type flow rate adjustment valve 21 of the fuel type heater 20 is different.

  The electric superheat control unit 84 controls the superheat control and electric side of the electric heater 30 based on the difference between the total superheated steam amount supplied from the fuel heater 20 that is the target of superheat control and the required superheated steam amount. The flow rate of the flow rate adjustment valve 31 is controlled. For example, as described above, when the required superheated steam amount is about 3500 kg / h and the number of superheat control targets is set to three, the superheated steam amount of 500 kg / h is supplied by the electric heater 30. The electric heater 30 and the electric side flow rate adjustment valve 31 are controlled. That is, it can be said that the amount of superheated steam that is not sufficient for the required amount of superheated steam is supplied by the electric heater 30. The electric heater 30 and the electric side flow rate adjustment valve 31 of the present embodiment can also set the amount of superheated steam to be supplied to zero. Further, the electric side flow rate adjustment valve 31 of the present embodiment can supply the same amount of superheated steam as the amount of superheated steam supplied by the fuel type flow rate adjustment valve 21 of the fuel heater 20. For example, four fuel heaters 20 whose supply superheated steam amount is set to 1000 kg / h are controlled to be overheated, and the opening degree of the electric side flow rate adjustment valve 31 of the electric heater 30 is the same as the supply superheated steam amount. By adjusting so that the amount of superheated steam can be supplied, the amount of superheated steam of 5000 kg / h can be supplied to the load equipment side as a whole of the steam superheat system 1.

  The electric superheat control unit 84 of the present embodiment monitors the measured value of the flow meter 50 and controls the electric heater 30 and the electric side flow rate adjustment valve 31 so that the flow rate of the superheated steam becomes constant. When the flow rate of superheated steam supplied to the load equipment side fluctuates, the temperature of the superheated steam may fluctuate. In the configuration of this embodiment, since the electric superheat control unit 84 adjusts the flow rate of the electric side flow rate adjustment valve 31 according to the flow rate variation, the temperature variation of the superheated steam caused by the flow rate variation is effectively prevented. It is suppressed.

  The steam superheating system 1 of the present embodiment is configured as described above. That is, the required superheated steam amount setting unit 81 sets the required superheated steam amount based on the measurement value of the flow meter 50, and the number of fuel heaters 20 is set based on the required superheated steam amount. The fuel-type overheat control unit 83 starts combustion control for the fuel-type heater 20 set as a target for overheat control, and also starts control for opening the fuel-type flow rate adjustment valve 21.

  The electric superheat control unit 84 starts the superheat control of the electric heater 30 and the flow rate of the electric side flow rate adjustment valve 31 so that the amount of superheated steam flowing through the superheated steam collecting line L50 matches the required amount of superheated steam. Adjust. That is, the difference between the total supplied superheated steam amount and the required superheated steam amount determined by the number of fuel heaters 20 is supplemented by the superheated steam supplied from the electric heater 30. As described above, the amount of superheated steam supplied by one or a plurality of fuel heaters 20 is set as the basic superheated steam amount (supply superheated steam amount), and the difference between the required superheated steam amount and the amount of superheated steam corresponding to the fluctuation are electric heaters. The steam superheating system 1 utilizing the characteristics of both the fuel heater 20 and the electric heater 30 is realized by being heated by 30. It should be noted that the required amount of superheated steam (measured value of the flow meter 50) fluctuates and the fuel heater 20 that is the target of overheat control is insufficient, or the number of fuel heaters 20 is larger than the required amount of steam. When the number becomes too large, the number of units is reset at an appropriate timing.

According to the steam superheating system 1 of the present embodiment described above, the following effects are obtained.
The steam superheating system 1 of the present embodiment includes a plurality of fuel heaters 20, a plurality of fuel type flow rate control valves 21 configured to be able to open and close a path of the fuel type steam supply line L20, an electric heater 30, and the like. The electric-side flow rate adjusting valve 31 arranged in the electric-side steam supply line L30 and configured to be capable of adjusting the flow rate, a control unit 80, and a storage unit 85 are provided. The control unit 80 performs the combustion control of the fuel type heater 20 set in the number setting unit 82 and the control for opening the fuel type flow rate adjustment valve 21 corresponding to the fuel type heater 20 and is required to be required. Based on the difference between the amount of superheated steam and the total amount of superheated steam supplied from the fuel heater 20 that is the target of superheat control, the flow rate of the electric side flow rate adjustment valve 31 and the overheating of the electric heater 30 are controlled.

  Thereby, most of the necessary superheated steam amount can be supplied by the fuel heater 20, and the remaining superheated steam can be supplied by the electric heater 30 that can accurately adjust the degree of superheat. Therefore, it is possible to realize the steam superheating system 1 capable of accurately supplying the flow rate of the superheated steam according to the required amount of superheated steam while avoiding an increase in required electric capacity of the entire steam superheated system 1. Furthermore, in this method, it is not necessary to frequently change the combustion control of the burner of the fuel heater 20, and it is efficient from the viewpoint of control and combustion. Since it is not necessary to follow the fluctuation of the requested amount on the load side, the combustion of the fuel heater 20 can be stably continued with a constant combustion amount.

  The electric superheat control unit 84 adjusts the flow rate of the electric side flow rate adjustment valve 31 following the fluctuation of the required superheated steam amount. Thereby, the temperature fluctuation of the superheated steam caused by the fluctuation of the flow rate of the superheated steam can be effectively reduced.

  The steam superheating system 1 of this embodiment includes a flow meter 50 that detects the flow rate of superheated steam supplied by the steam superheating system 1. And the control part 80 has the required superheated steam amount setting part 81 which sets a required superheated steam quantity based on the measured value of the flowmeter 50. FIG. Thereby, the fluctuation | variation of the flow volume of the superheated steam actually supplied by the steam superheating system 1 can be reflected correctly, and the temperature and supply amount of superheated steam can be controlled much more appropriately.

  The preferred embodiment of the steam superheating system of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be modified as appropriate.

  In the above embodiment, the required superheated steam amount is set based on the measurement value of the flow meter 50, but is not limited to this configuration. For example, a pressure detection unit (pressure sensor) is arranged in a superheated steam header (not shown in the above embodiment) to which the superheated steam collecting line L50 is connected, and the required superheated steam amount is set based on the pressure of the superheated steam header. It is good also as a structure. Thus, the setting method of required superheated steam amount can be changed suitably according to the situation.

  In the above embodiment, the fuel heater 20 in which the burner combustion is in the ON / OFF operation has been described as an example. However, the configuration of the fuel heater can be changed as appropriate according to circumstances. For example, a fuel type heater whose combustion amount is controlled in a stepwise manner, a fuel type heater whose combustion amount is proportionally controlled, and the like can be used as the fuel type heater of the steam superheating system of the present invention. A fuel-type heater that controls the amount of combustion by selectively turning ON / OFF the combustion, adjusting the size of the flame, etc., and gradually increasing or decreasing the amount of combustion according to the selected combustion position When the steam superheating system of the present invention is configured, the electric heater can absorb the fluctuation of the required superheated steam amount required from the load equipment side, so the combustion position of the fuel heater can be switched and started / stopped. Suppresses and stabilizes combustion. The fuel heater in which the combustion amount is continuously proportionally controlled in the range of 0% (no combustion) to 100% (maximum combustion amount) with respect to the combustion capacity (combustion amount in the maximum combustion state) is also described above. As in the case of the fuel heater that controls the amount of combustion in a stepwise manner, a constant combustion state can be continued, so that stabilization of combustion and further stabilization of superheated steam temperature can be achieved.

  In the above embodiment, the fuel-type flow rate adjustment valve 21 capable of adjusting the flow rate is employed as the first control valve, but it can be changed to an electromagnetic valve or the like that only opens and closes.

1 Steam superheating system 20 Fuel heater (fuel steam superheater)
21 Fuel-type flow rate adjustment valve (first control valve)
30 Electric heater (electric steam superheater)
31 Electric side flow control valve (second control valve)
50 Flowmeter (Flow rate detector)
80 Control unit 81 Required superheated steam amount setting unit 82 Number of units setting unit 83 Fuel type superheat control unit 84 Electric superheat control unit 90 Storage unit L20 Fuel type steam supply line (first steam supply line)
L30 Electric side steam supply line (second steam supply line)

Claims (3)

A steam superheating system that superheats steam and supplies superheated steam,
A plurality of fuel-type steam superheaters that superheat steam;
A plurality of first steam supply lines for supplying steam to each of the fuel-type steam superheaters;
A plurality of first control valves arranged in each of the plurality of first steam supply lines and configured to be able to open and close a path of the first steam supply line;
An electric steam superheater that superheats the steam;
A second steam supply line for supplying steam to the electric steam superheater;
A second control valve disposed in the second steam supply line and configured to allow flow rate adjustment;
A control unit for controlling the fuel-type steam superheater and the electric steam superheater based on a required amount of superheated steam;
A storage unit for storing the amount of superheated steam supplied to each of the fuel-type steam superheaters;
With
The controller is
A unit setting unit for setting the number of the fuel-type steam superheaters so that the total supply superheated steam amount of the fuel-type steam superheater to be superheated control does not exceed the range of the required superheated steam amount;
A fuel-type superheat control unit configured to perform combustion control of the fuel-type steam superheater set in the number setting unit and control to open the first control valve corresponding to the fuel-type steam superheater;
An electric superheat control unit for controlling the flow rate of the second control valve and the superheat of the electric steam superheater based on the difference between the required superheated steam amount and the total supply superheated steam amount;
Having a steam overheating system. The electric overheat control unit is
2. The steam superheating system according to claim 1, wherein the flow rate of the second control valve is adjusted following a change in the required superheated steam amount. A flow rate detector for detecting the flow rate of superheated steam supplied by the steam superheat system;
The controller is
The steam superheating system according to claim 1, further comprising a necessary superheated steam amount setting unit configured to set a necessary superheated steam amount based on a measurement value of the flow rate detection unit.

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