JPH1163410A - Feedwater control unit of auxiliary boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fill water automatically when the water level of a drum is lower than the predetermined water level at the start up of an auxiliary boiler. SOLUTION: A feedwater control unit of an auxiliary boiler is provided with a feedwater level instruction 14, a subtraction unit 17 subtracting level detecting signals 13 sent from a level meter 2 arranged to the drum from the feedwater level instruction 14 and a proportional integral controller 19 outputting control signals 15 to a feedwater flow controlling valve 7 for eliminating the deviation signals 18 from the subtraction unit 17. It is provided with a selector 24 for water filling switching between the outputting of the predetermined opening signal 25 to the feedwater supply flow control valve 7 when the level detection signal 13 is lower than the predetermined value and the outputting of the control signal 15 from the proportional integral controller 19 to the feedwater flow controlling valve 7 when the level detecting signal 13 is the predetermined level or higher at the generation of start up instruction 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water supply control device for an auxiliary boiler which is driven prior to the start of a main boiler and supplies steam for a gland packing seal for starting up a main steam turbine. .

[0002]

2. Description of the Related Art FIG. 2 is a front view showing an example of a conventional auxiliary boiler, wherein 1 is a water drum provided at a lower portion, and 2 is a steam drum provided at an upper portion. A large number of evaporating tubes 4 are provided between the steam chamber 1 and the steam drum 2 so as to surround the combustion chamber 3, and a burner 5 is provided at one end of the combustion chamber 3 (on the near side in FIG. 2). I have.
Reference numeral 6 denotes a casing that surrounds the entire outer periphery of the auxiliary boiler with a heat insulating material.

The steam drum 2 has a feedwater flow rate control valve 7.
The water 9 is supplied by a water supply pipe 8 provided with the steam. The steam 10 stored in the steam drum 2 is supplied to a gland packing or the like of a main steam turbine via a steam pipe 11. Has become.

Further, the steam drum 2 is provided with a level meter 12 for detecting the level (drum level) of the water 9 inside the steam drum 2, and a level detection signal 13 from the level meter 12 and a water supply level. A water supply controller 16 is provided which receives a command 14 and outputs a control signal 15 to the water supply flow rate control valve 7 so that the drum level of the steam drum 2 is maintained at a specified level L.

FIG. 3 shows an example of the configuration of a conventional water supply controller 16, in which a level detection signal 1 from the level meter 12 is provided.
Subtractor 1 for inputting and subtracting 3 and water supply level command 14
7 and a proportional-integral controller 19 for outputting a control signal 15 to the feedwater flow control valve 7 so that the deviation signal 18 from the subtractor 17 is eliminated.

In FIG. 3, reference numeral 20 denotes a switching unit, which performs switching by a fully closed command 21 generated by stopping the auxiliary boiler, and sends a fully closed signal 22 instead of the control signal 15 to the water supply flow rate control valve 7. Output. Also, 23
Is an automatic / manual switch.

According to the water supply controller 16 shown in FIG. 3, the level detection signal 13 from the level meter 12 and the water supply level command 1
4 is subtracted by the subtractor 17 to generate a deviation signal 18.
The control signal 15 is output from the proportional-integral controller 19 to the feedwater flow control valve 7 so that the deviation signal 18 disappears, and the opening of the feedwater flow control valve 7 is adjusted. The control is performed so that the drum level of the drum 2 matches the water supply level command 14 and is maintained at the specified level L.

When the auxiliary boiler is stopped, a full-close command 21 is input to the switch 20 so that the
The switch 20 held on the side is switched to the side b, whereby the fully closed signal 22 is output to the feedwater flow control valve 7, whereby the feedwater flow control valve 7 is fully closed and the steam is supplied to the steam drum 2. Water supply is stopped.

[0009]

However, the above-mentioned conventional auxiliary boiler water supply control device has the following problems when the auxiliary boiler is started.

That is, in the auxiliary boiler, the steam 10 in the steam drum 2 may be supplied to the utilization system by the steam pipe 11 even after the auxiliary boiler is stopped. In order to prevent the internal pressure of the steam drum 2 from increasing due to the generated steam 10, the steam 10
Is discharged to the outside. In such a case, the drum level of the steam drum 2 of the steam drum 2 is reduced. In some cases.

As described above, the auxiliary boiler stopped with the drum level of the steam drum 2 lower than the specified level L cannot be started as it is because of the safety and controllability of the auxiliary boiler.

[0012] For this reason, conventionally, when the auxiliary boiler is started, before starting the auxiliary boiler, the operator moves from the central operation room to the front of the auxiliary boiler and always visually checks the drum level of the steam drum 2. At this time, if the drum level is lower than the specified level L, the steam drum 2 is filled with water manually.

As described above, conventionally, every time the auxiliary boiler is started, it is necessary for the operator to check the drum level, and the operation is complicated, and the drum level is checked visually. Therefore, there is a problem that an accident may occur due to a decrease in the level due to forgetting to confirm or an operator's operation error.

The present invention has been made in view of the above circumstances, and when the auxiliary boiler is started, water supply control of the auxiliary boiler is performed so that water can be automatically filled when the drum level is lower than a specified level. It is intended to provide a device.

[0015]

According to the present invention, there is provided a subtractor for subtracting a feed water level command for controlling a drum level of an auxiliary boiler and a level detection signal from a level meter provided on a steam drum. A water supply control device for an auxiliary boiler having a proportional integration controller for outputting a control signal to a water supply flow rate control valve so as to eliminate a deviation signal from a calculator, wherein a level detection signal is specified when a boiler start command is generated. When the level is lower than the level, the set opening signal is output to the feedwater flow rate control valve, and when the level detection signal is higher than the specified level, the control signal from the proportional-integral controller is switched to output to the feedwater flow rate control valve. And a water supply control device for an auxiliary boiler.

According to the present invention, when the auxiliary boiler is started, when the drum level of the steam drum is lower than the specified level, water is automatically filled to maintain the drum level at the specified level. The operator can omit the visual check of the drum level and the manual water supply work that had to be performed every time the auxiliary boiler was started, thus reducing the burden on the operator and forgotten to confirm. And the occurrence of a drum level lowering accident caused by a driver's operation error or the like can be prevented.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of the present invention, in which the same reference numerals as in FIG. 3 denote the same components, and a water supply level for controlling a drum level of an auxiliary boiler. A subtractor 17 for subtracting a command 14 and a level detection signal 13 from a level meter 12 provided in the steam drum 2 of FIG. 2 and a feedwater flow rate adjustment so as to eliminate a deviation signal 18 from the subtracter 17. In a water supply control device for an auxiliary boiler including a proportional-integral controller 19 for outputting a control signal 15 to the valve 7, the proportional-integral controller 19 and the feedwater flow control valve 7 are provided.
, A water filling switch 24 is provided.

The water-filled switch 24 has a set opening signal 2
5 has been entered.

Also, a boiler start command 26 is input, and a level detection signal 13 from the level meter 12 is input. When the level detection signal 13 is below a specified level L, a switching signal 27 is sent to the water filling switch 24. There is provided a switching adjusting device 28 that outputs the output and switches the water filling switch 24 from the a side to the b side.

When the level detection signal 13 from the level meter 12 is equal to or higher than the specified level L in a state in which the boiler start command 26 is input to the switching adjustment device 28, the switching adjustment device 28 , Ie, the burner ignition ON for igniting the burner 5 in FIG.
A signal 29 is output.

The operation of the above embodiment will be described.

When a boiler start command is issued in the auxiliary boiler of FIG. 2, a boiler start command 26 is input to the switching adjusting device 28 in the water supply controller 16 of FIG.

The boiler start command is transmitted to the
Is input, the switching adjustment device 28 changes the level detection signal 13 input from the level meter 12 to the specified level L.
(FIG. 2) It is determined whether the level is higher or lower. When the level detection signal 13 is equal to or lower than the specified level L, a switching signal 27 is output to the water filling switch 24 to switch the water filling switch 24 to a
Switch from side to b side.

As a result, the set opening signal 25 is output to the feed water flow control valve 7, the feed water flow control valve 7 is opened to the set opening, and the water supply to the steam drum 2 in FIG. Done. At this time, the burner ignition ON signal 29 is not output from the switching adjusting device 28, so that the burner 5 is not ignited and the actual auxiliary boiler is not started.

Due to the water filling, the drum level of the steam drum rises, and the level detection signal 1
When 3 exceeds the specified level L, the switching adjustment device 28
The burner ignition ON signal 29 is output to the burner 5 in FIG. 2, and the auxiliary boiler is actually started by igniting the burner 5, and at the same time, the switching signal 27 output to the water filling switch 24.
Is stopped, whereby the water filling switch 24 is switched to the a side, and thereafter, the deviation signal 18 from the subtracter 17 which subtracts the water supply level command 14 and the level detection signal 13 is output.
The opening of the feedwater flow rate control valve 7 is automatically controlled by the control signal 15 output from the proportional-plus-integral controller 19 so as to eliminate.

If the level detection signal 13 from the level meter 12 is equal to or higher than the specified level L when the boiler start command 26 is input to the switching controller 28, the switching controller 28 immediately starts the burner. 5, the burner 5 is ignited by outputting a burner ignition ON signal 29, and at this time, the switching signal 27 is not output. Therefore, the water filling switch 24 uses the control signal 15 from the proportional-integral controller 19 as it is to supply water flow. The opening of the feedwater flow control valve 7 is automatically controlled so that the output is output to the control valve 7 and the drum level of the steam drum 2 is maintained at the specified level L.

When the auxiliary boiler is stopped, a full-close command 21 is input to the switch 20 and the switch 20 normally holding the a-side is switched to the b-side. Is output to the feedwater flow control valve 7, whereby the feedwater flow control valve 7 is fully closed and the supply of water to the steam drum 2 is stopped.

As described above, when the auxiliary boiler is started, when the drum level of the steam drum 2 is lower than the specified level L, water is automatically filled to maintain the drum level at the specified level L. Conventionally, the operation of visually confirming the drum level of the operator, which was performed every time the auxiliary boiler is started, and the manual water supply operation can be eliminated, thereby reducing the burden on the operator. It is possible to prevent the occurrence of a drum level drop accident due to forgetting to confirm or an operation error of the operator.

[0030]

As described above, according to the auxiliary boiler water supply control device of the present invention, when the auxiliary boiler is started, if the drum level of the steam drum is lower than the specified level, water is automatically filled. As a result, the drum level can be maintained at the specified level, so that the operator can visually check the drum level every time the auxiliary boiler is started, and can eliminate the manual water supply operation, Therefore, it is possible to provide an excellent effect that the burden on the operator can be reduced, and the occurrence of a drum level lowering accident due to forgetting to confirm or an operator's operation error can be prevented.

[Brief description of the drawings]

FIG. 1 is a control system diagram showing an example of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of an auxiliary boiler.

FIG. 3 is a control system diagram of a conventional auxiliary boiler water supply control device.

[Explanation of symbols]

 2 Steam drum 12 Level meter 13 Level detection signal 14 Water supply level command 15 Control signal 17 Subtractor 18 Deviation signal 19 Proportional integral controller 24 Water filling switch 25 Setting opening signal 26 Boiler start command L Standard level

Claims (1)

[Claims] 1. A subtracter for subtracting a feed water level command for controlling a drum level of an auxiliary boiler and a level detection signal from a level meter provided on a steam drum, and eliminating a deviation signal from the subtractor. A water supply control device for an auxiliary boiler having a proportional-integral controller for outputting a control signal to a water supply flow control valve as described above.When a boiler start command is issued, a set opening signal is output when a level detection signal is equal to or less than a specified level. An auxiliary boiler, comprising: a water filling switch for outputting to a feedwater flow control valve, and switching the control signal from the proportional-integral adjuster to be output to the feedwater flow control valve when a level detection signal is equal to or higher than a specified level. Water supply control device.