JP6939351B2 - Steam overheating system - Google Patents

Description

The present invention relates to a steam superheat system including a plurality of steam superheaters.

A steam superheater is known in which saturated steam generated by a steam generator such as a boiler is heated by a heater to supply superheated steam to a load device (Patent Document 1).
Further, there is known a steam superheat system in which a plurality of such superheaters are arranged in parallel, and superheated steam supplied from these superheaters is collected in a superheated steam header and supplied to a load device. In such a steam superheating system, the superheated steam header pressure decreases when the required steam amount (load amount) exceeds the superheated steam amount supplied from the steam superheater, and the superheated steam header pressure increases when the load amount decreases. Therefore, in order to maintain the superheated steam supply amount, the pressure of the superheated steam header is monitored and controlled to keep the pressure at a preset target pressure.

Japanese Unexamined Patent Publication No. 2014-55694

To start the steam superheated system, after establishing a state in which safety has been confirmed by the first start (also called "start in cold state"), the operation to change from the stopped state to the state where superheated steam can be supplied ("system start"). Also called) is performed. When the initial start-up of the steam superheat system is completed and stopped in the combustion standby state, the system start-up is performed.
The cold start is, for example, a start form when the steam superheat system 1 which has been stored for a long time is started when the power generation unit is stopped, and is a manned operation at the site (for example, release of the storage state, operation of various valves, etc. Power / operation switch on operation, safety confirmation, etc.) are required.
At system startup, the supply of saturated steam is started, and the steam superheat system 1 is prepared for stable superheated steam generation.

At the first startup of such a steam superheat system, it is necessary to start it manually for safety, but it is also necessary to start it manually at the time of system startup of the steam superheat system. In addition, at the time of start-up, it was necessary to manually send some superheated steam or saturated steam before reaching the superheated steam conditions related to the required temperature and pressure to the outside of the superheater system.

An object of the present invention is to provide a steam superheat system including a plurality of steam superheaters, which enables automation of start-up from a combustion standby state after the completion of initial start-up.

The present invention includes a main steam supply line whose upstream side is connected to a steam header for collecting saturated steam generated by a steam generator, and a steam supply line having a plurality of branched steam supply lines branching from the main steam supply line. A plurality of flow control valves arranged in each of the plurality of branched steam supply lines, and a plurality of superheated saturated steam connected to each of the plurality of branched steam supply lines on the downstream side and superheated from the saturated steam supplied from the branched steam supply lines. The steam superheater and a plurality of superheated steam lines in which the upstream side is connected to the plurality of superheater devices and the superheated steam superheated by the superheater device flows, and the downstream side of the plurality of superheated steam lines are connected to the plurality of superheated steam devices. A superheated steam supply line having a superheated steam collecting line in which superheated steam flowing through the superheated steam line is collected, and a plurality of superheated steam supply lines arranged corresponding to each of the plurality of superheated steam lines to detect the superheated steam temperature in the superheated steam line. The superheated steam temperature sensor, the superheated steam header connected to the downstream side of the superheated steam collecting line, and the upstream side are connected to a predetermined position of the superheated steam line or the superheated steam header to release the superheated steam. A line, a steaming valve arranged in the steaming line, a superheated steam air supply line whose upstream side is connected to the superheated steam header and whose downstream side is connected to a load device, and a superheated steam air supply line arranged in the superheated steam air supply line. A superheated steam air supply valve, a header pressure sensor that detects a superheated steam header pressure value that is a header pressure value inside the superheated steam header, and a number control unit that controls the plurality of superheated steam devices. The number control unit closes the superheated steam air supply valve according to a start instruction, bypasses at least one superheater, and supplies saturated steam of a first flow rate to the superheated steam header. The present invention relates to a superheater superheater system including a bypass control unit that raises a superheated steam header pressure value until it reaches a preset target pressure value.

Further, the bypass control unit bypasses the steam superheater by controlling the opening degree of the flow rate adjusting valve arranged in the branch steam supply line, and superheats the saturated steam at the first flow rate. It is preferable to supply the superheated steam header via the line and the superheated steam collecting line.

Further, it is preferable that the number control unit further includes a steaming control unit that controls the steaming valve so that the superheated steam header pressure value maintains the target pressure value.

Further, the unit control unit further shifts the remaining steam superheaters except the steam superheater that bypasses the saturated steam to the warm-up operation mode, and then shifts the steam superheater to bypass the saturated steam. It is preferable to provide a warm-up operation control unit that shifts to the warm-up operation mode and controls combustion of the steam superheater that has completed warming up in the minimum combustion state.

Further, the number control unit further includes an operation start control unit that opens the superheated steam air supply valve in response to the operation start instruction, and the steaming control unit further gives the operation start instruction. It is preferable to maintain the operation ready state in which superheated steam can be supplied by controlling the steaming valve until it is received.

Further, the operation start control unit further closes the superheated steam air supply valve in response to an operation standby instruction during the operation of the steam superheat system, and shifts the steam superheater to the operation ready state. It is preferable to let it.

According to the present invention, in a steam superheater system including a plurality of steam superheaters, it is possible to automate the start-up from the combustion standby state after the completion of the initial start-up.

It is a figure which showed schematicly the steam superheat system which is one Embodiment of this invention. It is a functional block diagram which shows the structure of the number control part. It is a flowchart which shows the processing flow from the system start-up to the operation stop in the steam superheat system of this embodiment. It is a flowchart which shows the processing flow from the system start-up to the operation stop in the steam superheat system of this embodiment. It is a flowchart which shows the processing flow at the time of a normal operation in the steam superheat system of this embodiment. It is a flowchart which shows a part of the processing flow at the time of a normal operation in the steam superheat system of this embodiment. It is a flowchart which shows the processing flow at the time of operation stop in the steam superheat system of this embodiment.

Hereinafter, preferred embodiments of the steam superheat system of the present invention will be described with reference to the drawings. The steam superheat system 1 of the present embodiment is a system that superheats saturated steam supplied from a boiler as a steam generator and supplies it to a load device. In addition, the "line" in this specification is a general term of a line capable of flowing a fluid such as a flow path, a path, and a pipeline.

As shown in FIG. 1, the steam superheat system 1 includes a plurality of heaters 20, a steam supply line 10, a fuel supply line 30, a superheated steam supply line 40, a superheated steam header 43, a header pressure sensor 52, and the like. It includes a header temperature sensor 53 and a number control unit 60 as a control unit.

[About heater 20]
The heater 20 superheats saturated steam to generate superheated steam, and in the steam superheat system 1 of the present embodiment, a plurality of heaters 20 are arranged in parallel. Each heater 20 is a gas-fired combustion burner type superheater, and the superheated steam superheated by these heaters 20 is collected and supplied to a load device (not shown). The heater 20 is not limited to the gas-fired combustion burner type steam superheater. The heater 20 may be an oil-fired combustion burner type steam superheater. Fuel is not limited.

The configuration of the heater 20 will be described. The heater 20 of the present embodiment includes a housing 25, a steam flow pipe 26, a burner (not shown), and a heater control unit 21.

The housing 25 houses a steam flow pipe 26, a burner, and the like inside. The steam flow pipe 26 is formed and arranged in a spiral shape inside the housing 25. The burner is arranged so as to form a flame in the upper part of the housing 25 and in the inner region of the spirally formed steam flow pipe 26.
The burner is composed of a pilot burner and a main burner. In the present embodiment, a pre-purge step for pre-purging the inner region (combustion chamber) of the steam flow pipe 26, an ignition try step for igniting the pilot burner, a pilot-only step for burning only the pilot burner, and a main try step for igniting the main burner. Combustion is started after the above. The combustion of the burner heats the saturated steam passing through the steam flow pipe 26 to generate superheated steam.

The heater control unit 21 controls the burner related to ignition, combustion, etc., and stops combustion for each heater 20. The heater control unit 21 of each heater 20 of the present embodiment is electrically connected to the number control unit 60, which will be described later.
The heater control unit 21 controls the start of combustion control of the heater 20 or the stop of combustion of the heater 20 based on the control signal from the number control unit 60. Further, the heater control unit 21 sets a target temperature of superheated steam and a required superheated steam amount (hereinafter, also referred to as “required steam amount”) based on a control signal from the number control unit 60.
The heater control unit 21 adjusts the opening degree of the flow rate adjusting valve 14 based on the required amount of steam.
In this way, the number control unit 60 adjusts the opening degree of the flow rate adjusting valve 14 via the heater control unit 21 so that the heater 20 generates the required amount of steam.
The heater control unit 21 controls the combustion amount of the burner so that the superheated steam detection temperature detected by the superheated steam temperature sensor 51 maintains the target temperature. The superheated steam temperature of the superheated steam superheated by the heater 20 is individually proportionally controlled on each heater side.
The details of the control related to the heater control unit 21 will be described later together with the description of the operation control by the number control unit 60.

[Steam supply line 10]
The steam supply line 10 is a supply path for supplying saturated steam to the heater 20. The steam supply line 10 of the present embodiment includes a main steam supply line 11 and a plurality of branched steam supply lines 12 that branch from the main steam supply line 11.

[Boiler as a steam generator]
The main steam supply line 11 is connected to a boiler (not shown) as a steam generator. The main steam supply line 11 of the present embodiment is connected to the boiler via a saturated steam header (not shown) in which saturated steam generated by the boiler is collected. The saturated steam collected in the saturated steam header is sent to a plurality of branched steam supply lines 12 through the main steam supply line 11.
In the boiler as a steam generator, the saturated steam header pressure value, which is the header pressure value inside the saturated steam header, maintains a preset target pressure value (hereinafter, referred to as “saturated steam header target pressure value”). It is controlled to do.

The upstream end of the branched steam supply line 12 is connected to the main steam supply line 11, and the downstream end of the branched steam supply line 12 is connected to the upstream end of the steam flow pipe 26 of the heater 20. A plurality of branched steam supply lines 12 are branched according to the number of heaters 20. The saturated steam sent through the main steam supply line 11 is supplied to each heater 20 through the branch steam supply line 12.

Further, in the branch steam supply line 12 of the present embodiment, a steam flow meter 13, a flow rate adjusting valve 14, a drain line 15, a steam trap 16, and a drain discharge valve 17 are arranged.

The steam flow meter 13 is arranged in each of the branched steam supply lines 12 and measures the flow rate of steam flowing through the branched steam supply line 12. The measurement information of the steam flow meter 13 is transmitted to the number control unit 60 directly or via the heater control unit 21.

The flow rate adjusting valve 14 is arranged on the downstream side of the steam flow meter 13 in the branch steam supply line 12, respectively. The flow rate adjusting valve 14 is an electric flow rate adjusting valve configured so that the flow rate of steam flowing through the branch steam supply line 12 can be adjusted. As described above, the flow rate adjusting valve 14 is controlled by the number control unit 60 via the heater control unit 21.
The flow rate adjusting valve 14 may be configured to include, for example, a main motor valve (not shown) and a warming motor valve (not shown).

The upstream end of the drain line 15 is connected to the downstream side of the flow control valve 14 in the branch steam supply line 12. The downstream side of the drain line 15 is branched into two.

The steam trap 16 is arranged on each of the drain lines 15. The drain is separated by the steam trap 16 and collected.

The drain discharge valve 17 is arranged in parallel with the steam trap 16 on each of the drain lines 15. The drain discharge valve 17 is composed of, for example, an electromagnetic valve that can be opened and closed.
The drain discharge valve 17 can discharge the initial drain when the heater 20 is started.

[Fuel supply line 30]
The fuel supply line 30 is a fuel gas supply path for supplying fuel gas to the heater 20. The fuel supply line 30 of the present embodiment includes a main fuel supply line 31 and a plurality of branched fuel supply lines 32 that branch from the main fuel supply line 31.

The upstream end of the main fuel supply line 31 is connected to a fuel gas supply source (not shown). The fuel gas supplied from the fuel gas supply source is sent to each of the branched fuel supply lines 32 branched into a plurality of branches through the main fuel supply line 31.

The upstream end of the branched fuel supply line 32 is connected to the main fuel supply line 31, and the downstream end of the branched fuel supply line 32 is connected to the heater 20. A plurality of branched fuel supply lines 32 are branched according to the number of heaters 20. The fuel gas sent through the main fuel supply line 31 is supplied to each heater 20 through the branch fuel supply line 32.

Further, a fuel adjusting valve 33 is arranged in the branch fuel supply line 32 of the present embodiment. The fuel regulating valve 33 is an electric valve configured so that the flow rate of the fuel gas flowing through the branched fuel supply line 32 can be adjusted.

[Superheated steam supply line 40]
The superheated steam supply line 40 is a supply path for supplying the superheated steam heated by the heater 20 to the load equipment. The superheated steam supply line 40 of the present embodiment includes a plurality of superheated steam lines 41 and a superheated steam collecting line 42 to which the superheated steam line 41 is connected.

The upstream end of the superheated steam line 41 is connected to the downstream end of the steam flow pipe 26 of the heater 20. Further, the downstream end of the superheated steam line 41 is connected to the superheated steam collecting line 42. The superheated steam heated by the heater 20 is sent to the superheated steam collecting line 42 through the superheated steam line 41. Further, the superheated steam line 41 is not provided with a check valve or the like, so that the superheated steam can move in both directions.

A superheated steam temperature sensor 51 is arranged in the superheated steam line 41. The superheated steam temperature sensor 51 is arranged corresponding to each of the plurality of superheated steam lines 41, and measures the temperature of the superheated steam superheated by the heater 20. The measurement information of the superheated steam temperature sensor 51 is transmitted to the heater control unit 21.
The superheated steam temperature sensor 51 can be arranged, for example, in the superheated steam line 41 or the heater 20 which is a steam superheater.

The downstream end of the superheated steam collecting line 42 is connected to the superheated steam header 43. Further, also in the superheated steam collecting line 42, a check valve or the like is not arranged so that the superheated steam can move in both directions.

The superheated steam header 43 collects the superheated steam heated by each heater 20 through the superheated steam supply line 40 and supplies the superheated steam to a load device (not shown).

The header pressure sensor 52 measures the pressure inside the superheated steam header 43. The header temperature sensor 53 measures the temperature inside the superheated steam header 43. These measurement information is transmitted to the number control unit 60. The pressure value inside the superheated steam header 43 detected by the header pressure sensor 52 is referred to as a superheated steam header pressure value. The pressure value inside the superheated steam collecting line 42 near the superheated steam header 43 may be used instead of the superheated steam header pressure value. As described above, the internal pressure value in the vicinity of the superheated steam header 43, which is substantially the same as the superheated steam header pressure value, may be used instead of the superheated steam header pressure value.
In the steam superheat system 1, the superheated steam header pressure value is controlled by the number control unit 60 so as to maintain a preset target pressure value. Hereinafter, unless otherwise specified, the target pressure value means the target pressure value related to the superheated steam header pressure value.

[Superheated steam steaming line 44]
The upstream side of the superheated steam steaming line 44 is connected to a predetermined position of the superheated steam line 41 or the superheated steam header 43. The superheated steam steaming line 44 is a steaming route for steaming superheated steam. A steaming valve 45 is arranged in the superheated steam steaming line 44.

The steaming valve 45 is arranged on the downstream side of the superheated steam steaming line 44. The steaming valve 45 is an electric valve, an air-driven valve, or the like configured so that the flow rate of superheated steam to be steamed from the superheated steam line 41 or the superheated steam header 43 can be adjusted. An on-off valve may be provided in the plurality of superheated steam steaming lines 44, and the flow rate of the superheated steam may be adjusted by opening and closing the superheated steam steaming line 44.
As a steaming control method, a continuous control method in which superheated steam is steamed by adjusting the superheated steam header pressure based on the valve opening degree of the steaming valve 45 can be applied. Further, using the steaming valve 45 as an on-off valve, for example, an intermittent control method for steaming superheated steam by adjusting the superheated steam header pressure based on the opening time and frequency of the steaming valve 45 may be applied.

[Superheated steam air supply line 46]
The upstream side of the superheated steam air supply line 46 is connected to the superheated steam header 43, and the downstream side thereof is connected to a load device (not shown). The superheated steam air supply line 46 is a supply path for supplying superheated steam to a load device (not shown). A superheated steam air supply valve 47 is arranged in the superheated steam air supply line 46.

The superheated steam air supply valve 47 is arranged on the downstream side of the superheated steam air supply line 46. The superheated steam air supply valve 47 is an electric valve, an air-driven valve, or the like that is configured to be able to adjust the flow rate of superheated steam supplied from the superheated steam header 43 to a load device (not shown).

Next, the number control unit 60 as a control unit of the steam superheat system 1 that controls a plurality of heaters 20 will be described. The number control unit 60 controls combustion of a plurality of heaters 20, opens and closes of valves such as a flow rate adjusting valve 14, a steaming valve 45, and a superheated steam air supply valve 47.
FIG. 2 is a block diagram showing the configuration of the number control unit 60. As shown in FIG. 2, the number control unit 60 includes a number setting unit 61, a preparation start control unit 62, a bypass control unit 63, a steaming control unit 64, a warm-up operation control unit 65, and an operation start control unit. It includes 66, a minimum combustion number setting unit 67, a combustion control unit 68, and a stop control unit 69.

[System start-up]
Before explaining each functional unit of the number control unit 60, the system start-up of the steam superheat system 1 will be described.
By pressing the operation preparation switch button of the number control panel (or central monitoring control panel) in the combustion standby state (power on state) of each device (boiler system as steam generator and steam superheater (heater)), The steam superheater system 1 starts the system startup and shifts to the operation preparation mode.
The maximum steam requirement, which is the sum of the maximum steam requirements of superheated steam used by the load equipment (not shown), is preset, and the number of heaters 20 that can meet the maximum steam requirement at system startup is set, for example. A heater that overheats (hereinafter referred to as "combustion control target heater") is set based on the priority order and the like.
Further, the target pressure value of the saturated steam header in the boiler as the steam generator and the target pressure value of the superheated steam header pressure value in the steam superheat system 1 are set in advance. After operation, the boiler as a steam generator is controlled so that the saturated steam header pressure value maintains a preset saturated steam header target pressure value. Similarly, after operation, the steam superheat system 1 is controlled so that the superheated steam header pressure value maintains a preset target pressure value.
The target pressure value of the superheated steam header pressure value is preferably set with a predetermined differential pressure so as to be smaller than the saturated steam header target pressure value. Details will be described later.
Further, instead of the differential pressure, a predetermined flow rate value related to the saturated steam flow rate supplied to the heater 20 is set, and the saturated steam flow rate supplied to the heater 20 is controlled to be equal to or higher than the predetermined flow rate value. May be good.

[Operation preparation mode]
In the operation preparation mode, saturated steam is generated by burning a boiler, and the saturated steam flows into the heater 20, and first, the superheated steam header pressure is the combustible pressure of the heater 20 (hereinafter, "heater combustible pressure"). Saturated steam is supplied to the superheated steam header 43 until it becomes), and then the heater 20 is instructed to permit combustion and burned to generate superheated steam. It means the operation mode until the state becomes. By closing the superheated steam air supply valve 47 arranged in the superheated steam air supply line 46 during the operation preparation mode, saturated steam or generated superheated steam is not supplied to the load equipment side. Be controlled.
The operation preparation mode is composed of a bypass stage, a warm-up operation stage, and an operation preparation completion stage.

[Bypass stage]
The bypass stage is a superheated steam header in which saturated steam is superheated through a predetermined number (one or more) of heaters 20 (hereinafter referred to as “bypass heaters”) in a combustion standby state before the start of warm-up operation of each heater 20. By supplying to 43, it means a stage in which the superheated steam header pressure value reaches the combustible pressure value of the heater 20.
Here, the bypass means a preset first flow rate (“for example, a main motor valve or a warming motor valve) by opening the flow rate adjusting valve 14 (for example, a main motor valve or a warming motor valve) corresponding to the bypass heater 20 in the combustion standby state. It means a form in which saturated steam of (also referred to as "bypass flow rate") flows into the superheated steam header 43 via the superheated steam line 41 via the steam flow pipe 26 arranged inside the housing 25. At this time, since the bypass heater 20 is in the combustion standby state, the saturated steam flows into the superheated steam header 43 without being superheated. The number of bypass heaters may be changed according to the operator's instruction. Further, as the bypass heater, it is preferable that the heater 20 having a lower priority is selected.

In the bypass stage, a part of the saturated steam that has flowed into the superheated steam collecting line 42 via the bypass heater 20 flows back through the other superheated steam line 41 and flows into the other heater 20. As a result, the saturated steam that has flowed back through the other superheated steam line 41 can heat the other combustion control target heaters, and drains the steam through the steam trap 16. By doing so, it is possible to reduce the cormorant _Oh Tahanma phenomenon.
Further, after the superheated steam header pressure value reaches the target pressure value (combustible pressure value of the heater 20) in the bypass stage, the superheated steam steaming line 44 is connected so that the superheated steam header pressure value maintains the target pressure value. The steam valve 45 to be arranged is controlled.

[Warm-up operation stage]
When a predetermined condition (for example, a condition in which the superheated steam header pressure value becomes equal to or higher than the target pressure value) is satisfied at the bypass stage, all the remaining combustion control target heaters 20 except the bypass heater (hereinafter, also referred to as “non-bypass heater”). For each unit (for example, with a time interval), a combustion permit is instructed to shift to warm-up operation. Then, when the warming up of all the non-bypass heaters is completed, the bypass heater 20 is sequentially instructed to permit combustion, and the operation shifts to the warming up operation to complete all the warming up of the bypass heater 20.
The predetermined condition at the bypass stage of the warm-up operation stage is a condition in which the overheated steam header pressure value is equal to or higher than the target pressure value, but a condition in which the saturated steam header pressure value is equal to or higher than the target pressure value may be used. However, it may be a condition that both conditions are satisfied.
Further, instead of waiting for the completion of warming up of all non-bypass heaters, warming up of the non-bypass heaters and bypass heaters may be started at predetermined intervals set in advance. The predetermined interval may be a constant value. Further, the predetermined interval may be set to be longer than a constant value. On the contrary, the predetermined interval may be shortened instead of a constant value.
In this way, in the warm-up operation stage, when a predetermined condition is satisfied, the non-bypass heater is instructed to permit combustion to shift to the warm-up operation, and then all the non-bypass heaters are warmed up, and then bypassed. This means the stage from when the heater 20 is instructed to permit combustion and the operation is shifted to the warm-up operation until the warm-up of all the bypass heaters is completed.
Warming is to heat and warm the steam to a predetermined temperature after the start of combustion of the heater 20 and before the superheated steam is supplied by the heater 20 in the heater 20 which is a steam superheater and the steam superheat system 1 including the heater 20. Means. In addition, warming includes the meaning of warming up as a general term because the pipes, heat transfer tubes, and the like are warmed by steam as preparation for warming up.
The warm-up operation is a second flow rate set in advance (hereinafter, "warm-up operation flow rate") by opening the flow rate adjusting valve 14 corresponding to the heater 20 (referred to as "warm-up operation heater") to be warm-up operation. It means an operation in which the saturated steam of (also referred to as) is supplied to the warming operation heater 20 and the combustion amount of the burner is controlled so that the superheated steam detection temperature detected by the superheated steam temperature sensor 51 becomes a predetermined temperature.

[Combustion Permit Directive]
Here, the conditions under which the number control unit 60 can instruct the heater 20 as the steam superheater to permit combustion will be described. When the saturated steam header and the superheated steam header 43 are simultaneously boosted in the bypass stage, the saturated steam header is operated until steaming is started by the control of the steaming valve 45 arranged in the superheated steam steaming line 44. The differential pressure between the pressure and the superheated steam header pressure becomes small. As described above, when the combustion of the heater 20 is started in a state where the differential pressure between the saturated steam header pressure and the superheated steam header pressure is small, there is a concern that the steam flow rate is small and the heater overheats and abnormally stops.
Therefore, in order to start combustion of the heater 20 (that is, give a combustion permission command to the heater 20), for example, the superheated steam header pressure value is smaller than the saturated steam header target pressure value by a predetermined differential pressure. It is necessary to be.
For example, the working steam pressure range of the heater 20 as a steam heating device is 1.50 MPa to 1.65 MPa, the normal working pressure range of the boiler as a steam generator is 1.37 MPa to 1.98 MPa, and the operation of the steam superheater 1 is started. When the difference between the saturated steam header pressure value and the superheated steam header pressure value required for is 0.15 MPa, the saturated steam header target pressure value is 1.90 MPa and the superheated steam header pressure value is 1.65 MPa. It can be set to provide a predetermined differential pressure (0.25 MPa).
Then, in the bypass stage, the saturated steam header pressure value is controlled by the number control device of the steam boiler, the target pressure value of 1.90 MPa is maintained, and the superheated steam header pressure value is steamed and controlled by the number control unit 60. The target pressure value of 1.65 MPa can be maintained. Therefore, when the conditions of the saturated steam header pressure value of 1.90 MPa or more and the superheated steam header pressure value of 1.65 MPa or more are satisfied, the combustion permission is instructed to the combustion control target heater 20. Conditions can be set. Then, for example, after instructing one heater 20 to permit combustion, the saturated steam header pressure value and the superheated steam header pressure value are controlled so as to maintain the set target pressure values, which is necessary. The differential pressure can be secured.
In the above explanation, for the sake of simplicity, the conditions under which the combustion permit can be commanded by setting the target pressure value and the set pressure value of the combustion permit (heater combustible pressure value) to the same value have been described. Not limited to. If the condition where the required differential pressure can be obtained can be maintained, the set pressure value (heater combustible pressure value) of the combustion permit may be set to a value smaller than the target pressure value. Further, the minimum steam flow rate may be secured instead of the differential pressure.

The heater 20 that has been warmed up is shifted to the minimum combustion state according to the instruction from the number control unit 60, and can maintain the state in which superheated steam can be supplied.
Here, the minimum combustion state means that the flow rate of saturated steam supplied to the heater 20 is a preset minimum flow rate (hereinafter, also referred to as "minimum steam flow rate"), and combustion is performed so that the superheated steam detection temperature becomes a predetermined temperature. It means a combustion state that controls the amount (combustion rate). The minimum steam flow rate may be, for example, 33% of the maximum steam flow rate value, but is not limited thereto.
Further, instead of fixing the flow rate of saturated steam supplied to the heater 20, the combustion rate of the heater 20 is fixed to a preset minimum combustion rate, and the heater is set so that the superheated steam detection temperature becomes a predetermined temperature. The combustion state that controls the flow rate of the saturated steam supplied to 20 may be set as the minimum combustion state. The minimum combustion rate may be, for example, 33% of the maximum combustion, but is not limited to this.
In the following description, unless otherwise specified, the minimum combustion state may be any of the above cases.
In the warm-up operation stage, the steaming valve 45 arranged in the superheated steam steaming line 44 is controlled so that the superheated steam header pressure value maintains a predetermined target pressure value.

[Operation ready stage]
In the operation preparation completion stage, all the combustion control target heaters 20 complete warming up and shift to the minimum combustion state, the superheated steam header pressure value maintains the target pressure value, and the superheated steam header detection temperature is a predetermined temperature. It means that it is detected that the temperature is maintained for a certain period of time.
When the operation preparation completion stage is reached, for example, the lamp may be turned on in the number control panel (and the central monitoring control panel). By doing so, the driver can confirm that the steam superheat system 1 is in the operation ready stage (a state in which superheated steam can be supplied). The lamp is not limited to lighting. For example, the driver may be notified that the superheated steam can be supplied by any means such as voice by a microphone and display by a display device.
In the operation preparation completion stage, the steaming valve 45 arranged in the superheated steam steaming line 44 is controlled so that the superheated steam header pressure value maintains a predetermined target pressure value.

[Operation mode]
The operation mode means an operation mode in which the superheated steam air supply valve 47 is opened to supply superheated steam to the load equipment.

[Transition from operation preparation mode to operation mode]
When the steam superheat system 1 shifts from the operation ready state to the normal operation, the superheated steam air supply valve 47 is controlled to shift from fully closed to fully open over time. Further, when the superheated steam air supply valve 47 is opened and the pressure value of the superheated steam header is lowered, the steaming valve 45 is controlled to be closed, and the steaming valve 45 is fully closed or the superheated steam header is closed. When the pressure value falls below a predetermined value, the number control unit 60 adjusts the opening degree of the flow rate adjusting valve 14 so that the heater 20 generates the required amount of steam. As described above, the heater control unit 21 controls the combustion amount of the burner so that the superheated steam detection temperature maintains the target temperature.
As a result, the steam superheat system 1 is controlled so that the required amount of superheated steam is supplied to the load equipment.

[Target pressure in operation preparation mode and operation mode]
The target pressure set in the operation preparation mode is preferably a pressure higher than the target pressure during normal operation. Further, the target pressure set in the operation preparation mode is controlled by the combustion control unit 64 when the combustion control target heater is controlled to burn in the minimum combustion state (also referred to as “low combustion standby”). The pressure may be set higher than the set target pressure (also referred to as “steaming pressure”) at the time of steaming.
More specifically, these pressures can be set to have the following relationship.
Target pressure during normal operation ≤ Steaming pressure during low fuel standby ≤ Target pressure during operation preparation mode.
By setting the target pressure value in the operation preparation mode high in this way, it is possible to suppress a pressure drop when the superheated steam air supply valve 47 is opened.

On the premise of the above, each functional unit provided in the number control unit 60 (number setting unit 61, preparation start control unit 62, bypass control unit 63, steaming control unit 64, warm-up operation control unit 65, operation start control unit 66, minimum The combustion number setting unit 67, the combustion control unit 68, and the stop control unit 69) will be described.

The number control unit 60 always controls combustion of at least the minimum number of combustion heaters 20 among all the heaters 20 set as control targets according to the maximum steam requirement input in advance in the minimum combustion state or higher. Therefore, the maximum steam requirement will be described first.

[Maximum steam requirement]
The maximum steam requirement means the total amount of steam required for the superheated steam used by the load equipment (not shown).

[Number setting unit 61]
The number setting unit 61 sets, for example, the number of heaters 20 to be controlled (overheating) according to the maximum steam requirement input in advance from the number control panel. Here, the maximum steam requirement means the total amount of steam required for the superheated steam used by the load equipment (not shown).
Specifically, the number setting unit 61 sets the number of heaters 20 so that the maximum steam requirement can be covered by the total steam amount obtained by totaling the maximum output steam amounts of each heater 20 set as a control target.
For example, when the maximum steam usage amount is 12 tons and the maximum output steam amount of each heater 20 is 1.5 tons, the number setting unit 61 sets the number of heaters 20 to be controlled to eight.
By doing so, the number of heaters 20 to be controlled can be appropriately optimized. In particular, it is effective when superheated steam is supplied to a plurality of superheated steam-using facilities at the same time. Further, when it is estimated that the maximum steam requirement will be reduced due to periodic maintenance of superheated steam-using equipment or long-term shutdown, the number of heaters 20 to be controlled can be reduced so that the heaters 20 are not operated more than necessary. Can be optimized.

[Preparation start control unit 62]
The preparation start control unit 62 activates each boiler by transmitting a standby release signal to the boiler system (not shown) as a steam generator in accordance with an instruction to start the system by pressing the operation preparation button, for example. To generate saturated steam, the steam superheat system 1 is put into the operation preparation mode. At the same time, the preparation start control unit 62 prevents the saturated steam from being supplied to the load device side in a state where the superheated steam air supply valve 47 arranged in the superheated steam air supply line 46 is closed.

[Bypass Control Unit 63]
The bypass control unit 63 selects a predetermined number (one or a plurality of) of combustion control target heaters 20 having a low priority as bypass heaters. The bypass control unit 63 sets the priority of the heaters 20 to be higher as the integrated operation time is shorter, and selects a predetermined number of heaters as bypass heaters in order from the lower priority set in this way. May be good.
The bypass control unit 63 is arranged in the branch steam supply line 12 so as to supply the saturated steam to the bypass heater at the first flow rate (“bypass flow rate”) preset in the heater 20. The regulating valve 14 is controlled. By doing so, saturated steam is supplied to the superheated steam header 43 via the superheated steam line 41 and the superheated steam collecting line 42.
By supplying the saturated steam of the first flow rate to the superheated steam header 43 via the bypass heater, the superheated steam header pressure value is raised until it reaches the target pressure value.

In this way, the bypass control unit 63 bypasses the inside of the heater 20 and supplies saturated steam to the superheated steam header 43 with the superheated steam air supply valve 47 closed, and the superheated steam header pressure value is the target pressure value. The amount of superheated steam fluctuates and becomes unstable due to the difference pressure between the inlet side (steam header (not shown)) and the outlet side (superheated steam header 43) of the heater 20 being too large. Can be prevented.
Further, as described above, the saturated steam flowing back through the other superheated steam line 41 can heat the other combustion control target heaters and drain the drain through the steam trap 16. By doing so, it is possible to reduce the cormorant _Oh Tahanma phenomenon.

[Steaming control unit 64]
The steaming control unit 64 controls the opening degree of the steaming valve 45 appropriately arranged in the superheated steam steaming line 44 so that the superheated steam header pressure value maintains a preset target pressure value (hereinafter, Also called "steaming control").
More specifically, the steaming control unit 64 superheats the superheated steam header pressure value so as to maintain the preset target pressure value after the superheated steam header pressure value reaches the target pressure value in the bypass stage. The opening degree of the steaming valve 45 arranged in the steam steaming line 44 is controlled.
Further, the steaming control unit 64 controls the opening degree of the steaming valve 45 so that the superheated steam header pressure value maintains a preset target pressure value in the warm-up operation stage.
Further, the steaming control unit 64 controls the steaming valve 45 so that the superheated steam header pressure value maintains a preset target pressure value even at the operation preparation completion stage until an operation instruction is received.
Further, the steaming control unit 64 controls the opening degree of the steaming valve 45 so that the superheated steam header pressure value maintains a preset target pressure value in the warm-up operation stage.
Further, the steaming control unit 64 controls the steaming valve 45 so that the superheated steam header pressure value maintains a preset target pressure value until an operation instruction is received at the operation preparation completion stage.
Further, in the case where the superheated steam header pressure value exceeds a preset target pressure value in the normal operation, for example, in a state where the heater 20 of the minimum number of combustion units is burning in the minimum combustion state. , The opening degree of the combustion valve 45 can be controlled so that the superheated steam header pressure value maintains the target pressure value (hereinafter, referred to as "combustion control"). In this way, when the heater 20 with the minimum number of combustions is burning in the minimum combustion state, a part of the superheated steam (the amount of steam obtained by subtracting the required steam amount from the amount of superheated steam generated in the minimum combustion state) is used. By steaming through the superheated steam combustion line 44, the superheated steam header pressure value can maintain the target pressure value.
Saturation based on continuous control of the opening degree of the flow rate adjusting valve 14 corresponding to the combustion control target heater 20 by the combustion control unit 68 described later in order for the superheated steam header pressure value to maintain the target pressure value. There is a flow rate control of the amount of steam (hereinafter referred to as "flow rate control").
The details of the transition from the flow rate control by the combustion control unit 68 to the flow rate control by the combustion control unit 64, or the shift from the discharge control by the combustion control unit 64 to the flow rate control by the combustion control unit 68 will be described later.

[Warm-up operation control unit 65]
When a predetermined condition is satisfied in the bypass stage, for example, after the superheated steam header pressure value reaches the target pressure value (heater combustible pressure value), the warm-up operation control unit 65 closes the superheated steam air supply valve 47. In this state, the remaining combustion control target heaters 20 (non-bypass heaters) except the bypass heaters are supplied with saturated steam at the second flow rate (warm-up operation flow rate) at the same time or with a predetermined time difference. The opening degree of the flow rate adjusting valve 14 is controlled (via each heater control unit 21) to shift to the warm-up operation mode.
The warm-up operation control unit 65 lowers the priority of the bypass heater 20 to shift to warm-up. By doing so, the bypass heater 20 is controlled to shift to the warm-up operation mode after the transition to the warm-up operation of the non-bypass heater 20 is completed. The warm-up operation control unit 65 completes the bypass control by shifting the bypass heater 20 to the warm-up operation.
The warm-up operation control unit 65 controls drainage and warm-up combustion of the non-bypass heater 20 that has shifted to the warm-up operation mode via the drain discharge valve 17.
When the warming of the non-bypass heater 20 or the bypass heater 20 is completed, the warming operation control unit 65 controls the combustion of the non-bypass heater 20 or the bypass heater 20 for which the warming is completed in the lowest combustion state, respectively. Combustion control of the combustion control target heater in the minimum combustion state in this way is called low combustion standby.
In the warm-up operation stage, the superheated steam air supply valve 47 is maintained in a closed state, so that the superheated steam generated by the heater that has completed warming up is controlled so as not to be supplied to the load device.

[Operation start control unit 66]
When the operation start control unit 66 detects that the predetermined condition is satisfied, it determines that the steam superheat system 1 is in an operation ready state in which superheated steam can be supplied to the load device, and for example, the number of units is controlled. The lamp can be turned on on the panel (and / or the central monitoring and control panel). By doing so, the driver can confirm that the steam superheat system 1 is ready for operation. Here, the predetermined conditions are, for example, that all the operable combustion control target heaters 20 have completed warming up, the superheated steam header pressure value maintains the target pressure value, and the superheated steam header detection temperature is constant at the predetermined temperature. It may be a condition for maintaining time.
The operation start control unit 66 is not limited to turning on the lamp on the number control panel (and / or the central monitoring control panel) when it is determined that the steam superheat system 1 is in the operation ready state. For example, the driver may be notified that the superheated steam can be supplied by any means such as voice by a microphone and display by a display device.

The operation start control unit 66 shifts the steam superheat system 1 to the operation mode in response to an operation instruction (for example, pressing an operation switch button) by the driver.
More specifically, the operation start control unit 66 gradually opens the superheated steam air supply valve 47 from the fully closed state over time in response to the driver's instruction for the main operation (for example, pressing the main operation switch). When it becomes fully open, it shifts to the fully open state, and when it becomes fully open, it is controlled to maintain the fully open state.
By shifting the superheated steam air supply valve 47 from the fully closed state to the fully open state over time, when the superheated steam header pressure value gradually decreases, the steaming valve 45 is closed by the steaming control unit 64. Is controlled.
After that, when the steaming valve 45 is fully closed or the superheated steam header pressure value falls below a predetermined value, the number control unit 60 determines the flow rate adjusting valve so that the heater 20 generates the required amount of steam. Adjust the opening degree of 14. As described above, the heater control unit 21 controls the combustion amount of the burner so that the superheated steam detection temperature maintains the target temperature.
As a result, the steam superheat system 1 is subsequently controlled so that the required amount of superheated steam is supplied to the load equipment.
In this way, the steam superheat system 1 can be started with a margin in advance, and all the combustion control target heaters 20 can be made to stand by in the operation ready state until the start of operation, so that the operation can be performed in a short time. It is possible to shift from the ready state to the operating state.

[Transition to operation ready state]
Further, the operation start control unit 66 closes the superheated steam air supply valve 47 when an operation standby instruction (for example, pressing the operation preparation button) is given during the operation of the steam superheat system 1, and the steam superheat system 1 Can be moved to the operation ready state.
By doing so, even if the operation of the steam superheat system 1 starts too early, the superheated steam generation state is maintained without stopping the combustion control target heater 20 by returning to the operation ready state. Superheated steam can be provided whenever superheated steam is needed.

[Minimum combustion number setting unit 67]
The minimum number of combustion units setting unit 67 sets the number of units equal to or less than the number of steam superheaters to be controlled set by the number of units setting unit 61 as the minimum number of combustion units that are always burned even when the required load is reduced. The minimum number of burned units may be set to the same number as the number set by the number setting unit 61.
As described above, it can be said that the followability to the load fluctuation is relatively high when all the number of heaters 20 to be controlled, which are set by the number setting unit 61, are burning in the minimum combustion state. However, when it is expected that the load fluctuation is not so large, if the number of heaters 20 that burn in the minimum combustion state is equal to or greater than the minimum number of combustions, it is possible to secure load followability that does not pose a problem in practical use. ..
For example, the minimum number of combustion units that can follow the load can be set to half or more of the number of controlled objects set by the number setting unit 61.

[Combustion control unit 68]
The combustion control unit 68 keeps the superheated steam header pressure value at a preset target pressure value with respect to the combustion control target heater 20 set in the heater that overheats by the number setting unit 61 during normal operation. , The opening degree of the flow rate adjusting valve 14 corresponding to each heater 20 is continuously controlled (flow rate control) via the heater control unit 21.
This is because the superheated steam header pressure value decreases when the required steam amount (load amount) exceeds the superheated steam amount supplied from the heater 20, and the superheated steam header pressure value decreases when the required steam amount (load amount) falls below. It is a control that utilizes the rising phenomenon. That is, by controlling the superheated steam header pressure value to be kept constant, it is possible to maintain an appropriate superheated steam supply amount with respect to the superheated steam load amount.
More specifically, the combustion control unit 68 sets a target at which the superheated steam header pressure value (or the internal pressure value in the vicinity of the superheated steam header 43 having substantially the same value as the superheated steam header pressure value) is set in advance. Calculate the required amount of steam to maintain the pressure value.
Based on the calculated required steam amount, the combustion control unit 68 calculates the required steam generation amount of each combustion control target heater 20 so that the steam generation amount of each combustion control target heater 20 is the same. The combustion control unit 68 continuously controls the opening degree of the flow rate adjusting valve 14 corresponding to each heater 20 via the heater control unit 21 based on the calculated required steam generation amount of the combustion control target heater 20.
As described above, the combustion amount (combustion rate) of each heater 20 is individually controlled by each heater control unit 21 so that the superheated steam detection temperature detected by the superheated steam temperature sensor 51 maintains the target temperature. Is proportionally controlled. The opening degree of the flow rate adjusting valve 14 corresponding to each heater 20 and the combustion amount (combustion rate) of each heater 20 are PID controlled (P control) so that the required steam generation amount and the target temperature can be maintained, respectively. Alternatively, it may be configured to perform PI control).

[Transition from flow rate control to exhalation control]
As described above, the number control unit 60 always keeps at least the minimum number of combustion heaters 20 in the minimum combustion state or higher among all the heaters 20 set as the control target heaters according to the preset maximum steam requirement. It is configured to control combustion. Hereinafter, the amount of superheated steam generated when the heater 20 having the minimum number of combustions is controlled to burn in the minimum combustion state is referred to as the minimum superheated steam flow rate.
As described above, the combustion control unit 68 has a flow rate adjusting valve corresponding to each heater 20 in order to generate a calculated required steam amount so that the superheated steam header pressure value maintains a preset target pressure value. The opening degree of 14 is controlled. When the superheated steam supply flow rate of the superheated steam supplied to the load device reaches the minimum superheated steam flow rate, the combustion control unit 68 uses the minimum superheated steam flow rate even if the required steam amount is smaller than the minimum superheated steam flow rate. The flow rate corresponding to each heater 20 is controlled so as to be fixed.
After that, when a predetermined condition is satisfied, the steaming control unit 64 shifts to the steaming control that controls the steaming valve 45 so that the superheated steam header pressure value maintains the target pressure value. Specifically, the steaming control unit 64 controls the superheated steam header pressure value to maintain the target pressure value by steaming a part of the superheated steam amount through the steaming valve 45.
Here, the predetermined conditions are, for example, the air flow rate of the superheated steam supplied to the load equipment (for example, the flow rate of the superheated steam flow meter (not shown) provided in the superheated steam air supply line 46, or the saturated steam. A state in which the total value of the flow meters 13) is equal to or less than a predetermined flow rate, and the heater 20 having the minimum number of combustion units is controlled to burn in the minimum combustion state (for example, the minimum combustion rate in which the combustion rate of the heater 20 is preset). It is preferable to set the condition that the commanded state) continues for a preset predetermined time.
If the transition condition from flow rate control to steaming control does not include the condition related to the air flow rate value of superheated steam, even if the load steam amount> the minimum superheated steam flow rate change, the superheated steam air flow rate ( There is a possibility that the superheated steam header pressure rises due to the sudden decrease in the load steam amount), the steaming control unit 64 starts the steaming control, and the combustion control unit 68 controls to reduce the saturated steam flow rate. Then, the superheated steam header pressure fluctuates greatly, and there is a possibility that the flow rate control and the steaming control are repeated.
In order to avoid such a situation, by including the condition related to the insufflation flow rate value of superheated steam as the transition condition from the flow rate control to the steaming control, it is possible to switch from the more stable flow rate control to the steaming control ( Migration) can be performed.

[Transition from steam release control to flow rate control]
As described above, when the transition from the flow rate control to the exhalation control is performed, the combustion control unit 68 commands each heater 20 to be in the minimum combustion state (for example, the combustion rate of the heater 20 is set to a preset minimum combustion rate). Combustion is controlled in this state. On the other hand, when the superheated steam header pressure value exceeds a preset target pressure value in a state where the heater 20 having the minimum number of combustions is burning in the minimum combustion state, the steaming control unit 64 determines the superheated steam header pressure. The opening degree of the steam valve 45 is controlled so that the value maintains the target pressure value.
When the steaming control unit 64 executes steaming control based on the opening degree of the steaming valve 45, the closed state of the steaming valve 45 continues for a predetermined time set in advance, or the superheated steam header pressure. When the value is lower than the preset predetermined pressure value (also referred to as "first pressure value"), the steaming control by the steaming valve 45 is stopped. It is desirable that the first pressure value is set lower than the target pressure value in the exhalation control.
By doing so, while the steaming control unit 64 is executing the steaming control by the steaming valve 45, for example, the amount of superheated steam supplied to the load device rapidly increases, and the superheated steam header pressure increases. The steaming control can be stopped immediately when the temperature drops sharply. Then, the combustion control unit 68 continuously controls the opening degree of the flow rate adjusting valve 14 corresponding to each heater 20 based on the required steam generation amount so that the superheated steam header pressure value maintains the target pressure value. .. In this way, it is possible to switch (shift) from more stable steam release control to flow rate control.

As described above, in the steam superheater system 1, the combustion control unit 68 always controls the combustion of at least the minimum number of combustion control target heaters 20 at a combustion load factor equal to or higher than the minimum combustion rate, and as described above, the predetermined conditions. When the condition is satisfied, the combustion control unit 64 controls the opening degree of the combustion valve 45 so that the superheated steam header pressure value maintains the target pressure value. After that, for example, when the required amount of steam increases and the closed state of the steaming valve 45 continues for a preset predetermined time, or when the superheated steam header pressure value is set to a preset predetermined pressure value (first pressure value). ), The steaming control is stopped and the flow rate is controlled by the combustion control unit 68. As a result, the load can be followed more stably.

[Stop control unit 69]
Finally, the combustion of the boiler and the stop control when stopping the combustion of the combustion control target heater 20 will be described.
For example, when the stop button of the number control panel (and the central monitoring control panel) is pressed by the driver, the stop control unit 69 stops combustion of the combustion control target heater 20 in the combustion state by transmitting, for example, a standby signal. At the same time, for example, by transmitting a standby signal to a number control device (not shown) of the boiler system, combustion of each boiler is stopped, and the superheated steam air supply valve 47 is controlled to be closed.
More specifically, in the case of normal stop, the stop control unit 69 first stops the combustion of the heater 20 when the stop button is pressed, and the control command of the closed state to the superheated steam air supply valve 47 continues for a predetermined time. Is output. The closed state of the superheated steam air supply valve 47 means a state in which there is substantially no steam air supply, and the open state of the superheated steam air supply valve 47 having almost no effect on the superheated steam header pressure. include.
The stop control unit 69 may fix the burning heater 20 to the minimum combustion state instead of stopping the combustion of the heater 20 by pressing the stop button. After that, when the superheated steam flow rate becomes equal to or less than a predetermined flow rate, the stop control unit 69 may stop the combustion of all the heaters 20 during combustion and close the superheated steam air supply valve 47.
After that, the stop control unit 69 performs steaming control that controls the opening degree of the steaming valve 45 based on the superheated steam header pressure, and stops steaming when the superheated steam header pressure falls below a predetermined pressure. In addition, in order to promote the discharge of the steam remaining in the system by the stop control unit 69, the target pressure of the steaming control when the heater combustion is stopped, the control parameters, or the time for maintaining the steaming valve open state after the heater combustion is stopped. Etc. may be set in advance.
The stop control unit 69 supplies saturated steam to the superheated steam header 43 via a predetermined number (one or more) of heaters 20 (bypass heaters) in the boiler system as a steam generator. Control to remove saturated steam. Stop control unit 69, by removing the saturated steam in the boiler system as a steam generator, it is possible to prevent multiple of c _o Tahanma by the saturated vapor is drained of.
In the case of an emergency stop, the stop control unit 69 stops the combustion of the combustion control target heater 20 in the combustion state by the stop operation, immediately closes the superheated steam air supply valve 47, and opens the opening degree of the steaming valve 45.

[Operation description]
Next, a series of flow of control by the number control unit 60 in the steam superheat system 1 including a plurality of heaters 20 will be described with reference to FIGS. 3 to 7. FIG. 3 is a flowchart showing a processing flow at the time of system startup. FIG. 4 is a diagram showing a processing flow related to the transition from the operation ready state to the operation state and the transition from the operation state to the operation ready state. FIG. 5 is a flowchart showing a processing flow during normal operation. FIG. 6 is a flowchart showing a part of the processing flow during normal operation in FIG. FIG. 7 is a flowchart showing a processing flow at the time of operation stop (normal stop).
In this processing flow, it is assumed that the number of combustion control target heaters 20 is set in advance by the number setting unit 61. Further, it is assumed that the minimum combustion number of the combustion control target heater 20 is set by the minimum combustion number setting unit 67. Further, it is assumed that the first flow rate, the second flow rate, the target pressure value in the superheated steam header 43, the predetermined temperature, and the like are set in advance.

[Processing flow at system startup]
Referring to FIG. 3, in step ST1, the number control unit 60 (preparation start control unit 62) closes the superheated steam air supply valve 47 in accordance with the instruction to start the system.

In step ST2, the number control unit 60 (preparation start control unit 62) activates each boiler by transmitting a standby release signal to the boiler system that generates saturated steam.

In step ST3, the number control unit 60 (bypass control unit 63) sets a preset first flow rate (bypass flow rate) with respect to the heaters 20 (bypass heaters) of a predetermined number of bypasses (one or a plurality of units). The flow rate adjusting valve 14 arranged in the branch steam supply line 12 is controlled so as to supply saturated steam at.

In step ST4, the number control unit 60 (warm-up operation control unit 65) determines whether or not the superheated steam header pressure value is equal to or higher than the target pressure value. When the superheated steam header pressure value becomes equal to or higher than the target pressure value (Yes), the process proceeds to step ST5. If the superheated steam header pressure value is not equal to or higher than the target pressure value (No), the process returns to step ST4.

In step ST5, the number control unit (steaming control unit 64) controls the steaming valve 45 so that the superheated steam header pressure value maintains a preset target pressure value.
In addition, also in step ST6 and later, the number control unit (steaming control unit 64) controls the steaming valve 45 so that the superheated steam header pressure value maintains the preset target pressure value.

In step ST6, the number control unit (warm-up operation control unit 65) provides a second flow rate with respect to the combustion control target heaters 20 (non-bypass heaters) of all the remaining units except the bypass heater at the same time or with a predetermined time difference. The flow rate adjusting valve 14 is controlled so as to supply saturated steam at (warm-up operation flow rate), and the mode is shifted to the warm-up operation mode. More specifically, the number control unit (warm-up operation control unit 65) causes the non-bypass heater 20 that has shifted to the warm-up operation mode to control drainage and warm-up combustion via the drain discharge valve 17.

In step ST7, the number control unit (warm-up operation control unit 65) controls combustion in the minimum combustion state when the warm-up of the non-bypass heater 20 shifted to the warm-up operation mode is completed.

In step ST8, the number control unit 60 (warm-up operation control unit 65) determines whether or not all the non-bypass heaters 20 that have shifted to the warm-up operation mode have completed warm-up. When all the non-bypass heaters 20 have been warmed up (Yes), the process proceeds to step ST9. If all the non-bypass heaters 20 have not been warmed up (No), the process returns to step ST6.

In step ST9, the number control unit 60 (warm-up operation control unit 65) supplies saturated steam to the bypass heater 20 at the second flow rate (warm-up operation flow rate) at the same time or with a predetermined time difference. The flow rate adjusting valve 14 is controlled to shift to the warm-up operation mode. More specifically, the number control unit (warm-up operation control unit 65) causes the bypass heater 20 that has shifted to the warm-up operation mode to control drainage and warm-up combustion via the drain discharge valve 17.

In step ST10, the number control unit 60 (warm-up operation control unit 65) determines whether or not the bypass heater 20 that has shifted to the warm-up operation mode has completed warming up. When the bypass heater 20 has completed warming up (Yes), the process proceeds to step ST11. If the bypass heater 20 has not completed warming up (No), the process returns to step ST9.

Referring to FIG. 4, in step ST11, the number control unit 60 (operation start control unit 66) determines whether or not a predetermined condition is satisfied. If the predetermined condition is satisfied (Yes), the process proceeds to step ST12. If the predetermined condition is not satisfied (No), the process returns to step ST11.

In step ST12, the number control unit 60 (operation start control unit 66) informs the driver that the operation preparation is completed by, for example, turning on the lamp on the number control panel (and / or the central monitoring control panel). Notify.

In step ST13, the number control unit 60 (operation start control unit 66) determines whether or not an operation instruction (for example, pressing an operation switch button) by the driver has been given. When the operation instruction is given (Yes), the process proceeds to step ST14. If no operation instruction has been given (No), the process returns to step ST13.

In step ST14, the number control unit 60 (operation start control unit 66) shifts the steam superheat system 1 to the operation mode. More specifically, the number control unit 60 (operation start control unit 66) starts supplying superheated steam to the load device by changing the superheated steam air supply valve 47 from the closed state to the open state.

In step ST15, the number control unit 60 performs normal operation. The detailed processing flow during normal operation will be described later.

In step ST16, the number control unit 60 (operation start control unit 66) determines whether or not an operation standby instruction (for example, pressing the operation preparation button) has been given. When the operation standby instruction is given (Yes), the process proceeds to step ST17. If no operation standby instruction has been given (No), the process returns to step ST15.

In step 17, the number control unit 60 (operation start control unit 66) closes the superheated steam air supply valve 47.

In step 18, the steam superheat system 1 is moved to the operation ready state. Then, the process proceeds to step ST13.

[Processing flow during normal operation]
Next, the detailed processing flow during normal operation in step 15 of FIG. 4 will be described with reference to FIG. In the following processing flow, it is assumed that the minimum number of combustion units is set to be equal to the number of control target heaters 20 set by the number setting unit 61. The processing flow when the minimum number of combustion units is set to a value smaller than the number of heaters 20 to be controlled set by the number setting unit 61 will be described later.
Referring to FIG. 5, in step ST21, the number control unit 60 (combustion control unit 68) calculates the required steam amount so that the superheated steam header pressure value maintains a predetermined pressure value.

In step ST22, the number control unit 60 (combustion control unit 68) calculates the required steam generation amount of each combustion control target heater 20 based on the calculated required steam amount.

In step ST23, the number control unit 60 (combustion control unit 68) detects whether or not the required amount of steam generated by each combustion control target heater 20 is equal to or greater than the amount of steam generated in the minimum combustion state. If the amount of steam generated in the minimum combustion state or more (Yes), the process proceeds to step ST25. If it is lower than that, the process proceeds to step ST24.

In step ST24, the number control unit 60 (combustion control unit 68) burns each combustion control target heater 20 in the minimum combustion state, and the number control unit (steaming control unit 64) sets the superheated steam header pressure value. Controls the steam valve 45 so that it maintains a preset target pressure value. Then, the process proceeds to step ST21.

In step ST25, the number control unit 60 (combustion control unit 68) determines whether or not the steam release valve 45 is in the open state. When the steaming valve 45 is in the open state (Yes), the process proceeds to step ST26. When the steaming valve 45 is in the closed state (No), the process proceeds to step ST27.

In step ST26, the number control unit (steaming control unit 64) controls the steaming valve 45 so that the superheated steam header pressure value maintains a preset target pressure value. Then, the process proceeds to step ST21.

In step ST27, the number control unit 60 (combustion control unit 68) adjusts the flow rate corresponding to each combustion control target heater 20 via the heater control unit 21 based on the calculated required steam generation amount of the combustion control target heater 20. The opening degree of the valve 14 is continuously controlled, and the combustion amount of the heater 20 is controlled. Then, the process proceeds to step ST21.
The processing flow during normal operation has been described above, but in step ST23 described above, it is detected whether or not the required amount of steam generated by each combustion control target heater 20 is equal to or greater than the amount of steam generated in the minimum combustion state, and the minimum combustion is performed. When the amount of steam generated in the state or more (Yes), the process proceeds to step ST25, but instead, it is detected whether or not the required amount of steam generated by each combustion control target heater 20 is equal to or more than the predetermined amount of steam. If the amount of steam generated in the minimum combustion state or more (Yes), the process may proceed to step ST25. Further, in step ST23 described above, it is detected whether or not the required steam generation amount of each combustion control target heater 20 is equal to or greater than the amount of steam generated in the minimum combustion state and equal to or greater than the predetermined amount of steam, and the minimum combustion state is detected. If the amount of steam generated in (Yes) is equal to or greater than the amount of steam generated in (Yes), the process may proceed to step 25.

[About unit reduction control]
A processing flow when the minimum number of combustion units is set to a value smaller than the number of heaters 20 to be controlled, which is set by the number setting unit 61, will be described with reference to FIG. FIG. 6 shows a processing flow performed in place of step ST24 described in FIG.

First, in step ST24-1, it is determined whether or not the number of heaters 20 being burned exceeds the minimum number of burned heaters. If the number of heaters 20 being burned does not exceed (that is, is equal to) the minimum number of burners, the process proceeds to step ST24-2. If the number of heaters 20 being burned exceeds the minimum number of burned heaters, the process proceeds to step ST24-3.
In step ST24-2, the number control unit 60 (combustion control unit 68) is in a state where each combustion control target heater 20 is burned in the minimum combustion state, and the number control unit (steaming control unit 64) is in a superheated steam header. The steam valve 45 is controlled so that the pressure value maintains a preset target pressure value. Then, the process returns to step ST21.
In step ST24-3, it is detected whether or not the state in which the burning heater 20 burns in the minimum combustion state continues for a preset predetermined time. If it continues for a predetermined time, the process proceeds to step ST24-4. If it has not continued for a predetermined time, the process returns to step ST21.
In step ST24-4, the number control unit 60 selects one heater 20 during combustion and controls to stop combustion (also referred to as “reduction control”). Then, the process returns to step ST21.
As described above, when the minimum number of combustion units is set to a value smaller than the number of heaters 20 to be controlled set by the number setting unit 61, the number control unit 60 (combustion control unit 68) has the number of combustion units. When is larger than the minimum combustion number, the reduction control is performed, and when the combustion number is equal to the minimum combustion number, the steam release valve 45 is controlled.

[Processing flow when operation is stopped]
Referring to FIG. 7, in step ST31, the number control unit 60 (stop control unit 69) detects whether or not the operation stop instruction has been given by the driver. When the operation stop instruction is detected (Yes), the process proceeds to step ST32. If the operation stop instruction is not detected (No), the process returns to step ST31.

In step ST32, the number control unit 60 (stop control unit 69) stops the combustion of the combustion control target heater 20 in the combustion state, closes the superheated steam air supply valve 47, stops the combustion of each boiler, and releases steam. Steaming control is performed to control the opening degree of the valve 45.

In step ST33, it is determined whether or not the superheated steam header pressure value is below the predetermined pressure value. If it falls below (Yes), the process proceeds to step ST34. If it is not below (No), the process returns to step ST33.

In step ST34, the number control unit 60 (stop control unit 69) stops steaming.
According to the steam superheat system 1 of the present embodiment described above, the following effects are obtained.

The number control unit 60 of the steam superheat system 1 of the present embodiment closes the superheated steam air supply valve 47 in accordance with the start instruction, and then bypasses at least one heater 20 to obtain the saturated steam of the first flow rate. Is provided to the superheated steam header 43 to raise the superheated steam header pressure value until it reaches a preset target pressure value.
As a result, the amount of superheated steam caused by the difference pressure between the inlet side connected to the steam header of the steam superheater and the outlet side connected to the superheated steam header 43 of the superheater is too large, and the amount of superheated steam becomes unstable. It is possible to prevent it.

Further, the bypass control unit 63 bypasses the heater 20 by controlling the opening degree of the flow rate adjusting valve 14 arranged in the branch steam supply line 12, and superheats the steam at the first flow rate to the superheated steam line 41 and the steam line 41. It is supplied to the superheated steam header 43 via the superheated steam collecting line 42.

Further, the number control unit 60 may further include a steaming control unit 64 that controls the steaming valve 45 so that the superheated steam header pressure value maintains the target pressure value.
As a result, in the operation preparation mode (bypass stage, warm-up operation stage, and operation preparation completion stage), the superheated steam air supply valve 47 is maintained in the closed state, and the superheated steam header pressure value maintains the target pressure value. Is possible.

All the remaining combustion control target heaters 20 except the bypass heater that bypasses the saturated steam are shifted to the warm-up operation mode, and then the bypass heater that bypasses the saturated steam is shifted to the warm-up operation mode, and the heater 20 that has been warmed up is completed. Is provided with a warm-up operation control unit 65 that controls combustion in the minimum combustion state.
By controlling the combustion of the heater 20 that has been warmed up in the minimum combustion state, it is possible to maintain the steam superheat system 1 in a state in which superheated steam can be supplied (operation ready state).

Further, the number control unit 60 further includes an operation start control unit 66 that opens the superheated steam air supply valve 47 in response to the operation start instruction, and the steaming control unit 64 further gives an operation start instruction. By controlling the steaming valve 45 until it receives it, it maintains an operation ready state in which superheated steam can be supplied.
By doing so, the heater 20 can be started with a margin in advance, and then the heater 20 can be made to stand by in the operation ready state without stopping until the start of the operation.

Further, the operation start control unit 66 closes the superheated steam air supply valve 47 in response to the operation standby instruction given during the operation of the steam superheat system 1, and puts the steam superheat system 1 in the operation ready state. Migrate.
By doing so, even if the superheated steam air supply valve 47 is opened early and the operation of the steam superheat system 1 starts too early, the steam superheat system 1 is stopped by returning to the operation ready state. It is possible to maintain a state in which superheated steam can be generated without causing the superheated steam to be generated, and to provide superheated steam whenever superheated steam is required.

Although the preferred embodiments of the steam superheater of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be appropriately modified.

[Modification 1]
In the warm-up operation stage of the present embodiment, all the remaining combustion control target heaters 20 (non-bypass heaters) except the bypass heater are shifted to the warm-up operation one by one (for example, with a time interval), and all non-bypasses are performed. When the warming up of the heater is completed, the bypass heater 20 is then sequentially shifted to the warming up operation to complete all the warming up of the bypass heater 20, but the present invention is not limited to this.
For example, the combustion control target heaters 20 (non-bypass heaters) of all the remaining units excluding the bypass heater may be simultaneously shifted to the warm-up operation, or the combustion control target heaters 20 (non-bypass heaters) of all the remaining units excluding the bypass heater may be shifted to the warm-up operation at the same time. ), One or more units may be sequentially shifted to warm-up operation. Further, when all the non-bypass heaters have been warmed up, the bypass heaters 20 may be simultaneously shifted to the warm-up operation, or one or more units may be sequentially shifted to the warm-up operation to warm up all the bypass heaters 20. You may want to complete it.
Further, instead of waiting for the completion of warming up of all non-bypass heaters, warming up of the non-bypass heaters and bypass heaters may be started at predetermined intervals set in advance. The predetermined interval may be a constant value. Further, the predetermined interval may be set to be longer than a constant value. On the contrary, the predetermined interval may be shortened instead of a constant value.

[Modification 2]
In the present embodiment, the steaming control unit 64 is configured to apply a continuous control method for steaming superheated steam by adjusting the superheated steam header pressure based on the valve opening degree of the steaming valve 45. Not limited to this. The steaming control unit 64 may apply an intermittent control method for steaming superheated steam by adjusting the superheated steam header pressure based on the opening time of the steaming valve 45 and its frequency.

[Modification 3]
In the present embodiment, a gas-fired combustion burner method is applied to the heater 20, but the heater 20 is not limited to this. For example, it may be configured to heat by another means such as a halogen lamp.

[Modification example 4]
In the present embodiment, the number control unit 60 controls the flow rate adjusting valve 14 via the heater control unit 21, but the number control unit 60 may directly adjust the opening degree of the flow rate adjusting valve 14. good.

1 Steam superheat system 10 Steam supply line 11 Main steam supply line 12 Branch steam supply line 13 Steam flow meter 14 Flow control valve 15 Drain line 16 Steam trap 17 Drain discharge valve 20 Heater (steam superheater)
21 Heater control unit 25 Housing 26 Steam flow pipe 30 Fuel supply line 31 Main fuel supply line 32 Branch fuel supply line 33 Fuel adjustment valve 40 Overheated steam supply line 41 Overheated steam line 42 Overheated steam collecting line 43 Overheated steam header 44 Overheated steam Steaming line 45 Steaming valve 46 Superheated steam air supply line 47 Superheated steam air supply valve 51 Superheated steam temperature sensor 52 Header pressure sensor 60 Number control unit (control unit)
61 Number setting unit 62 Preparation start control unit 63 Bypass control unit 64 Steaming control unit 65 Warm-up operation control unit 66 Operation start control unit

Claims (6)

A steam supply line having a main steam supply line whose upstream side is connected to a steam header for collecting saturated steam generated by a steam generator and a plurality of branched steam supply lines branching from the main steam supply line, and a steam supply line having a plurality of branched steam supply lines.
A plurality of flow control valves arranged in each of the plurality of branched steam supply lines, and
A plurality of steam superheaters connected to the downstream side of the plurality of branched steam supply lines and superheating the saturated steam supplied from the branched steam supply lines.
A plurality of superheated steam lines in which the upstream side is connected to the plurality of steam superheaters and the superheated steam heated by the steam superheater flows, and the downstream sides of the plurality of superheated steam lines are connected to flow through the plurality of superheated steam lines. A superheated steam supply line having a superheated steam collecting line where the superheated steam is collected, and
A plurality of superheated steam temperature sensors arranged corresponding to each of the plurality of superheated steam lines and detecting the superheated steam temperature in the superheated steam line, and a plurality of superheated steam temperature sensors.
A superheated steam header connected to the downstream side of the superheated steam collecting line,
A steaming line whose upstream side is connected to a predetermined position of the superheated steam line or the superheated steam header to steam the superheated steam.
The steaming valve arranged in the steaming line and
A superheated steam supply line whose upstream side is connected to the superheated steam header and whose downstream side is connected to a load device,
A superheated steam air supply valve arranged in the superheated steam air supply line and
A header pressure sensor that detects the overheated steam header pressure value, which is the header pressure value inside the overheated steam header, and
A unit control unit that controls the plurality of steam superheaters is provided.
The number control unit
After the superheated steam air supply valve is closed according to the start instruction, at least one steam superheater is bypassed and saturated steam of the first flow rate is supplied to the superheated steam header to supply the superheated steam header. A steam superheat system equipped with a bypass control unit that raises the pressure value until it reaches a preset target pressure value. The bypass control unit
By controlling the opening degree of the flow rate adjusting valve arranged in the branched steam supply line, the steam superheater is bypassed and the saturated steam is transferred to the superheated steam line and the superheated steam collecting line at the first flow rate. The steam superheat system according to claim 1, wherein the superheated steam header is supplied to the superheated steam header via the above. The number control unit
The steam superheat system according to claim 1 or 2, further comprising a steaming control unit that controls the steaming valve so that the superheated steam header pressure value maintains the target pressure value. The number control unit further
All the remaining steam superheaters except the steam superheater that bypassed the saturated steam were shifted to the warm-up operation mode, and then the steam superheater that bypassed the saturated steam was shifted to the warm-up operation mode to complete warming up. The steam superheater according to claim 3, further comprising a warm-up operation control unit that controls combustion of the steam superheater in a minimum combustion state. The number control unit further
An operation start control unit for opening the superheated steam air supply valve in response to an operation start instruction is provided.
The steaming control unit further
The steam superheat system according to claim 4, wherein an operation ready state in which superheated steam can be supplied is maintained by controlling the steaming valve until the operation start instruction is received. The operation start control unit further
The steam superheat system according to claim 5, wherein during the operation of the steam superheat system, the superheated steam air supply valve is closed and the steam superheater is moved to the operation ready state in response to an operation standby instruction. ..

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