KR101558099B1 - Boiler control device and control method - Google Patents

Abstract

The present invention provides a boiler control device and a control method which more properly controls a conductivity of a boiler water in a boiler drum. According to an embodiment of the present invention, provided is a boiler control device which comprises: a water level gauge; a water supply valve; a blow valve; a first flow meter; a second flow meter; a third flow meter; a conductivity meter; a first control unit; and, a second control unit. The water level gauge measures a water level in the drum. The water supply valve controls a flux of the supplied water. The blow valve controls a flux of blow. The first flow meter measures the flux of the supplied water. The second flow meter measures a flux of steam. The third flow meter measures the flux of blow. The conductivity meter measures the conductivity of the water in the drum. The first control unit controls the water supply valve to make the water level uniform. The second control unit calculates a conductivity after a certain time has passed based on the results of the measurements of the conductivity meter, the second flow meter, and the third flow meter; and controls the blow valve to let conductivity be within a set scope by responding to the results of the calculation.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a boiler control apparatus,

An embodiment of the present invention relates to a boiler control device and a control method for controlling the conductivity of a boiler water in a boiler drum to fall within a set range.

There is a boiler control device that controls the amount of boiler water in the boiler drum to be substantially constant by adjusting the flow rate of the boiler water to be blown and the flow rate of the boiler water to be supplied in response to the flow rate of the steam to be discharged . Hereinafter, the flow rate of the boiler water to be blown is referred to as " blow water flow rate ", and the flow rate of the boiler water to which water is supplied is referred to as " feed water flow rate ". The boiler control device maintains a substantially constant flow rate of the blowing water when the conductivity of the boiler water in the boiler drum (hereinafter referred to as " drum conductivity ") is within the set range. When the drum conductivity is out of the setting range, the boiler control device controls the drum conductivity to be within the set range by adding or subtracting a certain amount of the blowing-out flow rate.

Therefore, when the flow rate of the blowing water, which is a factor of lowering the drum conductivity, is large with respect to the feed flow rate corresponding to the steam flow rate, which is a factor for increasing the drum conductivity, the drum conductivity is shifted to the lower setting range. For example, since the flow rate of the blowing air is increased as long as the proper drum conductivity is maintained, the temperature in the boiler drum is lowered, resulting in an energy loss.

In addition, when the blowing flow rate is small relative to the feed flow rate corresponding to the steam flow rate, the drum conductivity is shifted to the higher setting range, which causes the scale attachment. For this reason, it is preferable that the boiler control device can more appropriately control the drum conductivity.

Patent Document 1: JP-A-2009-30817

An embodiment of the present invention provides a boiler control apparatus and a control method that can more appropriately control the conductivity of a boiler water in a boiler drum.

According to an embodiment of the present invention, there is provided a boiler having a water level meter, a water feed valve, a blow valve, a first flow meter, a second flow meter, a third flow meter, a conductivity meter, a first control section, A control device is provided. The level gauge measures the level of the boiler water stored in the boiler drum. The water supply valve adjusts the flow rate of the boiler water supplied to the boiler drum. The blow valve adjusts the flow rate of the boiler water to be blown from the boiler drum. The first flow meter measures the flow rate of the boiler water supplied to the boiler drum. The second flow meter measures the flow rate of the steam emitted from the boiler drum. The third flow meter measures the flow rate of the boiler water to be blown from the boiler drum. The conductivity meter measures the conductivity of the boiler water stored in the boiler drum. The first control unit controls the water supply valve so that the water level is constant based on the measurement result of the water level meter and the measurement result of the first flow meter. Wherein the second control unit calculates the conductivity after a predetermined time has elapsed based on the measurement result of the conductivity meter, the measurement result of the second flow meter, and the measurement result of the third flow meter, And controls the blow valve so that the electric conductivity falls within a set range.

There is provided a boiler control device and a control method capable of more appropriately controlling the conductivity of the boiler water in the boiler drum.

1 is a block diagram schematically showing a boiler system according to an embodiment;
2 is a flowchart schematically showing an example of the operation of the boiler control apparatus according to the embodiment;

Hereinafter, each embodiment will be described with reference to the drawings.

The drawings are schematic or conceptual, and the relationship between the thickness and the width of each portion, the ratio of the sizes between the portions, and the like can not necessarily be the same as the reality. Even when the same portions are shown, the dimensions and ratios of the portions may be different from each other according to the drawings.

In the specification and drawings, elements similar to those described with reference to the drawings already described are denoted by the same reference numerals, and detailed description thereof will be appropriately omitted.

1 is a block diagram schematically showing a boiler system according to an embodiment.

1, the boiler system 2 includes a boiler drum 4, a water supply tank 5, a water feed pump 6, a blow-water storer tank 8, a boiler control unit 10, Respectively.

The boiler drum (4) stores the boiler water in an internal space. The boiler water stored in the boiler drum 4 is heated by a heat source not shown. The boiler drum (4) receives the boiler water and the steam generated by the heating. The boiler drum 4, in other words, is a steam drum. The boiler drum 4 may be connected to the water drum through, for example, a pipe. The heating of the boiler water by the heat source may be performed in the boiler drum 4, in the water drum, or in the pipeline between the boiler drum 4 and the water drum. The boiler system 2 may also include a heat source, a water drum, and the like.

The water supply tank 5 is connected to the boiler drum 4 through a pipe or the like. The water supply tank (5) stores the number of boilers to be supplied to the boiler drum (4). The boiler water may be, for example, water treated by a predetermined water treatment.

The water supply pump 6 is provided on the piping path between the boiler drum 4 and the water supply tank 5. That is, the water supply pump 6 is connected to the boiler drum 4 and the water supply tank 5 through piping or the like. The water supply pump 6 feeds the boiler water stored in the water supply tank 5 to the boiler drum 4. The water supply pump 6 sends the boiler water to the boiler drum 4 by, for example, applying pressure to the pipe between the boiler drum 4 and the water supply tank 5.

The blown water tank 8 is connected to the boiler drum 4 through a pipe or the like. The blow-out storm tank 8 stores the boiler water blown from the boiler drum 4. In other words, the blow-by water excellent tank 8 stores the number of boilers discharged from the boiler drum 4.

The boiler control apparatus 10 includes a water level meter 12, a water supply valve 14, a blow valve 16, a conductivity meter 18, a first flow meter 21, a second flow meter 22, A third flow meter 23, a first control unit 31, and a second control unit 32. As shown in Fig.

The water level gauge 12 is attached to the boiler drum 4. The water level gauge 12 measures the water level of the boiler water stored in the boiler drum 4. The water level gauge 12 is electrically connected to the first control portion 31, The water level gauge 12 inputs the measurement result of the water level of the boiler water to the first control unit 31. [

The water supply valve 14 is provided on the piping path between the boiler drum 4 and the water supply tank 5. The water supply valve 14 is connected to the boiler drum 4 and the water supply tank 5 through a pipe. The water supply valve 14 opens and closes, for example, a pipe between the boiler drum 4 and the water supply tank 5. Thereby, the water supply valve 14 adjusts the flow rate of the boiler water supplied to the boiler drum 4. In this example, a water supply valve 14 is provided between the boiler drum 4 and the water feed pump 6. The water supply valve 14 may be provided between the water supply tank 5 and the water feed pump 6, for example.

The blow valve 16 is provided on the piping path between the boiler drum 4 and the blow-by water excellent tank 8. The blow valve 16 is connected to the boiler drum 4 and the blow-out storm tank 8 through a pipe. The blow valve 16 opens and closes, for example, a pipe between the boiler drum 4 and the blow-by water excellent tank 8. Thereby, the blow valve 16 adjusts the flow rate of the boiler water to be blown from the boiler drum 4.

The conductivity meter 18 measures the conductivity of the boiler water stored in the boiler drum 4 (hereinafter referred to as drum conductivity). The drum conductivity is, in other words, the resistance per unit volume of the boiler water stored in the boiler drum 4. [ In other words, it is the amount of impurities contained in the unit volume of the boiler water stored in the boiler drum 4. In this example, the conductivity meter 18 is provided on the piping path between the boiler drum 4 and the blow-out storm tank 8. The conductivity meter 18 measures the drum conductivity by the conductivity of the boiler water blown from the boiler drum 4, for example. The conductivity meter 18 is electrically connected to the second control unit 32. [ The conductivity meter 18 inputs the measurement result of the drum conductivity into the second control unit 32. [ The position of the conductivity meter 18 is not limited to the above, but may be any arbitrary position where the drum conductivity can be measured. The conductivity meter 18 may be provided in the boiler drum 4, for example.

The first flow meter 21 is provided on the pipeline between the boiler drum 4 and the water supply tank 5. The first flow meter 21 measures the flow rate of the boiler water supplied to the boiler drum 4 (hereinafter referred to as the feed water flow rate). The first flow meter 21 is electrically connected to the first control unit 31. The first flow meter 21 inputs the measurement result of the feed water flow rate to the first control unit 31. In this example, the first flow meter 21 is provided between the boiler drum 4 and the water supply valve 14. The position of the first flow meter 21 is not limited to this position but may be arbitrarily positioned on the piping path between the boiler drum 4 and the water supply tank 5.

The second flow meter 22 is provided on the path of the pipe which supplies steam discharged from the boiler drum 4 to an external device or the like. Thus, the second flow meter 22 measures the flow rate of the steam discharged from the boiler drum 4 (hereinafter referred to as the steam flow rate). The second flow meter 22 is electrically connected to the second control unit 32. The second flow meter 22 inputs the measurement result of the steam flow rate to the second control unit 32. [

A pressure gauge 25 and a thermometer 26 are also provided on the piping route of the steam. The pressure gauge 25 measures the pressure of the steam emitted from the boiler drum 4. The thermometer 26 measures the pressure of the steam emitted from the boiler drum 4. The pressure gauge 25 and the thermometer 26 are electrically connected to the second control unit 32. Each of the pressure gauge 25 and the thermometer 26 inputs the measurement result to the second control unit 32. In addition, the pressure gauge 25 and the thermometer 26 are provided according to need and can be omitted.

The third flow meter 23 is provided on the piping path between the boiler drum 4 and the blow-out storey tank 8. The third flow meter 23 measures the flow rate of the boiler water to be blown from the boiler drum 4 (hereinafter, referred to as blow-off flow rate). The third flow meter 23 is electrically connected to the second control section 32. The third flow meter 23 inputs the measurement result of the blow-by gas flow rate to the second control unit 32. In this example, a third flow meter 23 is provided between the blow valve 16 and the blow-out storm tank 8. The position of the third flow meter 23 is not limited to this, and any position on the piping path between the boiler drum 4 and the blown water tank 8 is preferable.

The first controller 31 has a level calculator 31a and a flow calculator 31b. The level calculating section 31a calculates the amount of correction of the feed water flow rate based on the water level measured by the water level gauge 12. The level calculating section 31a calculates a correction amount of the feed water flow rate for making the water level of the boiler water in the boiler drum 4 a predetermined water level. The level calculating section 31a calculates the correction amount by, for example, the PI calculation.

The flow rate computation unit 31b computes an operation amount of the water supply valve 14 in accordance with the computation result of the level computation unit 31a based on the computation result of the level computation unit 31a and the measurement result of the first flow meter 21 . The flow rate computation unit 31b computes the manipulated variable of the water supply valve 14, for example, by PI computation.

The first control unit 31 controls the water supply valve 14 in response to the operation amount calculated by the flow rate calculation unit 31b. The first control unit 31 controls the water supply valve 14 so that the water level of the boiler water in the boiler drum 4 is constant based on the measurement result of the water level gauge 12 and the measurement result of the first flow meter 21 ). In other words, the first control unit 31 controls the water supply flow rate so that the water level is constant.

From the boiler drum 4, a predetermined amount of steam is always discharged. From the boiler drum 4, a predetermined amount of boiler water is always blown. The first control section 31 controls the water supply valve 14 so that the steam flow rate, the blowing-out flow rate, and the feed flow rate become substantially constant. The blow may be temporarily stopped.

The second control unit 32 calculates the drum conductivity after a predetermined time has elapsed based on the measurement result of the conductivity meter 18, the measurement result of the second flow meter 22, and the measurement result of the third flow meter 23 And controls the blow valve 16 so that the drum conductivity falls within the set range in response to the calculation result.

For example, based on the measurement result of the second flow meter 22, the second control unit 32 calculates the increase amount of the drum conductivity after a predetermined time has passed following the discharge of the steam. The second control section 32 calculates the decrease amount of the drum conductivity after a predetermined time period following the blowing, based on the measurement result of the conductivity meter 18 and the measurement result of the third flow meter 23. The second control section 32 calculates the drum conductivity after a predetermined time has elapsed from the calculated increase amount and decrease amount. Then, the second control section 32 determines the blowing good flow rate on the basis of the calculation result of the drum conductivity after a predetermined time has elapsed, and controls the blowing valve 16 in accordance with the determined blowing good flow rate.

The second control unit 32 has a flow rate calculation unit 32a. The flow rate calculator 32a calculates the manipulated variable of the blow valve 16 in accordance with the calculated flow rate of the blown fine flow and the determined result of the flow rate of the blown air based on the measured flow rate of the third flow rate meter 23. The flow rate computation unit 32a computes the manipulated variable of the blow valve 16 by, for example, PI computation. The second control section 32 controls the blow valve 16 in response to the operation amount calculated by the flow amount calculating section 32a. Thereby, the second control unit 32 allows the drum conductivity to be within the set range.

Here, the predetermined time is T. Let DL be the quantity of boiler water stored in the boiler drum (4). Let BL be the good flow rate. JL is the flow rate of boiler water supplied with the discharge of steam. And the drum conductivity measured at the conductivity meter 18 is UdO. Let Uk be the conductivity of the boiler water supplied. The drum conductivity after a predetermined time has passed is defined as Udx.

The quantity DL is controlled substantially constant by the first control section 31 as described above. Therefore, the quantity DL is stored in the second control section 32 as a constant value. The quantity DL may be calculated in real time by the second control unit 32 based on the measurement result of the water level gauge 12, for example.

The conductivity Uk of the boiler water supplied is measured in advance and stored in the second control unit 32 as a constant value. The conductivity Uk can be measured by providing a separate conductivity meter on the pipeline between, for example, the boiler drum 4 and the water supply tank 5, measuring it in real time and inputting it to the second controller 32 It is also good.

The flow rate JL of the boiler water supplied with the discharge of the steam is calculated based on the measurement results of the second flow meter 22, the pressure gauge 25 and the thermometer 26, for example, ). The second control section 32 may calculate the flow rate JL only from the measurement result of the second second flow meter 22, for example. However, the flow rate JL is calculated from the measurement results of the second flow meter 22, the pressure gauge 25 and the thermometer 26 as described above. Thereby, it is possible to more accurately calculate the flow rate JL.

The total amount of the boiler water supplied with the discharge of the steam from the present time to the passage of the predetermined time (T) is expressed as " JL x T ".

The increase in the conductance after the passage of the predetermined time (T) due to the discharge of the vapor by the conductivity Uk is expressed as " JL x T x Uk ". In other words, " L x T x Uk " is an increase amount of an impurity (material related to conductivity) in the boiler water after a predetermined time (T) has elapsed following the discharge of the vapor.

The increase amount of the electric conductivity after the elapse of the predetermined time (T) due to the discharge of the vapor by the quantity (DL)

Quot; JL x T x Uk / DL ".

Similarly, the total amount of the boiler water supplied with the blow from the present time until the passage of the predetermined time (T) is represented by "BL × T".

The amount of increase of the conductance after the lapse of the predetermined time (T)

Quot; BL x T x Uk ".

On the other hand, since the boiler water of the drum conductivity UdO is discharged, the amount of reduction of the conductance after the lapse of the predetermined time (T)

Quot; BL x T x UdO ". However, the change in the drum conductivity UdO during discharge is small and ignored.

The drum conductivity UdO is larger than the electric conductivity Uk of the water supply. Therefore, the amount of decrease in the conductance after the lapse of the predetermined time (T)

Quot; BL x T (UdO-Uk) ".

Thereby, the reduction amount of the electric conductivity after the lapse of the predetermined time (T)

Quot; BL x T (UdO-Uk) / DL ".

As described above, the drum electrical conductivity Udx after the lapse of the predetermined time T from the current drum electrical conductivity UdO is calculated by the following equation: UdO = UdO / From this,

Udx = UdO + (JL x T x Uk / DL) - (BL x T x (UdO-Uk) / DL)

Can be calculated by the first equation shown below.

When the above-described first equation is summarized with respect to the blow-by gas flow rate BL,

BL = JL 占 Uk / (UdO-Uk) + DL 占 (UdO-Udx) / (UdO-Uk)) / T

.

When the drum electrical conductivity Udx is within the set range to be put in, the drum electrical conductivity Udx is supposed to be equal to the drum electrical conductivity UdO in the above equation.

That is, it is assumed that (UdO-Udx) = 0.

In this case,

BL = (JL x Uk) / (UdO-Uk)

, The blow-by gas flow rate BL is determined. Thereby, the drum conductivity Udx can be set within the set range.

On the other hand, when the drum conductivity Udx is within the setting range desired to be inserted, the drum conductivity Udx is replaced with the target value Uds in the above equation. In other words,

BL = JL 占 UkI (UdO-Uk) + DL 占 (UdO-Uds) I (UdO-Uk) IT

, The blow-by gas flow rate BL is determined.

As a result, the drum conductivity after the elapse of the predetermined time T can be set as the target value Uds. The target value Uds is set within the setting range of the drum conductivity. The target value Uds is set to, for example, a median value between the upper limit and the lower limit of the set range. The target value Uds may be any value between the upper limit and the lower limit of the set range.

The second control section 32 calculates the drum conductivity Udx after the elapse of the predetermined time T by the above-described first equation. Then, it is determined whether or not the drum conductivity Udx is within the set range. When it is determined that the flow rate is within the set range, the blow-by gas flow rate BL is determined by the above-described second equation, and the blow-valve 16 is controlled in accordance with the determined blow-off flow rate. On the other hand, when it is determined that the flow rate is not within the set range, the blow-by gas flow rate BL is determined by the above-described third equation and the blow-valve 16 is controlled in accordance with the determined blow-

The second control section 32 also determines whether or not the drum electric conductivity UdO is within the set range based on the drum electric conductivity UdO measured by the conductivity meter 18. If the second control section 32 determines that it is within the set range, the second control section 32 executes a process for calculating the drum conductivity Udx in accordance with the above-described first equation. On the other hand, when it is determined that the flow rate is not within the set range, the blow-by gas flow rate BL is determined by the above-described third equation and the blow-valve 16 is controlled in accordance with the determined blow-

The first control unit 31 and the second control unit 32 are provided by, for example, separate processors. The first control unit 31 and the second control unit 32 may be provided in one processor. That is, the first control unit 31 and the second control unit 32 may be logical blocks provided in one processor.

2 is a flow chart schematically showing an example of the operation of the boiler control apparatus according to the embodiment.

2, the first control section 31 of the boiler control apparatus 10 controls the water level of the boiler water in the boiler drum 4 to be substantially constant when the operation is started (step S01) . The first control unit 31 controls the water supply valve 14 so that the water level of the boiler water in the boiler drum 4 becomes constant based on the measurement result of the water level gauge 12 and the measurement result of the first flow meter 21 .

When the operation is started, the second control section 32 measures the drum conductivity UdO (step SO2). That is, the second control unit 32 acquires the measurement result of the drum conductivity UdO from the conductivity meter 18 in response to the start of the operation.

The second control section 32 determines whether or not the acquired drum conductivity UdO is within the set range (step S03).

When it is determined that the drum conductivity UdO is within the set range, the second control unit 32 calculates the drum conductivity Udx after the lapse of a predetermined time by the above-described first equation (step SO4).

After calculating the drum conductivity Udx, the second controller 32 determines whether or not the drum conductivity Udx is within the set range (step S05).

When the drum conductivity Udx is determined to be within the set range, the second control unit 32 determines the blow-by gas flow rate BL by the above-described second equation and determines the blow-by gas flow rate BL in accordance with the determined blow- (Step S06).

On the other hand, when it is determined that the drum conductivity Udx is not within the set range, the second control unit 32 determines the blow-by gas flow rate BL in accordance with the above-described third equation, 16 (step S07).

If it is determined in step S03 that the drum conductivity UdO is not within the set range, the second control unit 32 determines the blow-by gas flow rate BL by the above-described equation (3) To control the blow valve 16.

Thus, the boiler control apparatus 10 according to the present embodiment is configured to control the boiler control unit 10 based on the measurement result of the conductivity meter 18, the measurement result of the second flow meter 22, and the measurement result of the third flow meter 23, The drum electric conductivity Udx after a predetermined time T has elapsed is calculated and the blow valve 16 is controlled so that the drum electric conductivity falls within the set range in accordance with the calculation result.

Thus, in the boiler control apparatus 10 according to the present embodiment, for example, when the drum conductivity is out of the set range, compared with a control device for adding or subtracting a certain amount of blowing flow rate, Can be set within a longer time setting range.

Therefore, for example, it is possible to suppress the occurrence of scale adhesion due to deviation of the drum conductivity from the higher side of the setting range. For example, it is possible to suppress the increase in the blowing-out flow rate more than necessary due to deviation of the drum conductivity from the lower side of the setting range. For example, it is possible to suppress the occurrence of energy loss due to a decrease in the temperature in the boiler drum 4 accompanied by an increase in the blowing-off flow rate.

As described above, in the boiler control apparatus 10 according to the present embodiment, the conductivity of the boiler water in the boiler drum 4 can be more appropriately controlled.

While several embodiments of the present invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other forms, and various omissions, substitutions, and alterations can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention as defined in the claims and their equivalents.

2: Boiler system 4: Boiler drum
5: Water tank 6: Feed pump
8: Blowout tank 1a: Boiler control device
12: Gauge 14: Water valve
16: Blow valve 18: conductivity meter
21: first flow meter 22: second flow meter
23: third flow meter 25: pressure gauge
26: thermometer 31:
32:

Claims (5)

A water level meter for measuring the water level of the boiler water stored in the boiler drum,
A water supply valve for adjusting a flow rate of the boiler water supplied to the boiler drum,
A blow valve for adjusting a flow rate of the boiler water blown from the boiler drum,
A first flow meter for measuring a flow rate of the boiler water supplied to the boiler drum,
A second flow meter for measuring a flow rate of steam emitted from the boiler drum,
A third flow meter for measuring a flow rate of the boiler water blown from the boiler drum,
A conductivity meter for measuring the conductivity of the boiler water stored in the boiler drum,
A first controller for controlling the water supply valve so that the water level is constant based on a measurement result of the water level meter and a measurement result of the first flow meter,
Calculating the conductivity after a predetermined time elapses based on the measurement result of the conductivity meter, the measurement result of the second flow meter, and the measurement result of the third flow meter, and determining the conductivity within a set range And a second control unit for controlling the blow-off valve to control the blow-off valve. The method according to claim 1,
Wherein the second control unit calculates an increase amount of the conductivity after the passage of the predetermined time following the discharge of the vapor based on the measurement result of the second flow meter and measures the measurement result of the conductivity meter and the measurement of the third flow meter Calculating a reduction amount of the electric conductivity after the predetermined time has elapsed following the blow, calculating the electric conductivity after the predetermined time elapses from the increase amount and the decrease amount, and calculating the electric conductivity after the predetermined time elapses Wherein the control unit determines the flow rate of the boiler water to be blown based on the calculation result, and controls the blow valve in response to the determined flow rate. 3. The method of claim 2,
The predetermined time is T,
The number of boiler water stored in the boiler drum is DL,
The flow rate of the boiler water to be blown is BL,
JL is the flow rate of the boiler water supplied with the discharge of steam,
The conductivity measured by the conductivity meter is UdO,
Let Uk be the conductivity of the boiler water supplied,
The electric conductivity after the predetermined time has elapsed is defined as Udx,
And a target value of the conductivity set in the setting range is Uds,
Wherein the second control unit comprises:
Udx = UdO + (JL x T x Uk / DL) - (BL x T x (UdO-Uk) / DL)
(Udx) is calculated by the first equation, and when the conductivity Udx is within the set range,
BL = (JL x Uk) / (UdO-Uk)
, The flow rate of the boiler water to be blown is determined, and when the electric conductivity Udx is not within the setting range,
BL = JL x Uk / (UdO-Uk) + DL x ((UdO-Uds) / (UdO-Uk)) / T
Wherein the flow rate of the boiler water to be blown is determined by a third equation expressed by the following equation. The method of claim 3,
Wherein the second control unit determines the flow rate of the boiler water to be blown by the third equation when the conductivity UdO is not within the set range. The boiler drum is controlled so that the water level is constant based on the measurement result of the water level meter for measuring the water level of the boiler water stored in the boiler drum and the measurement result of the first flow meter for measuring the flow rate of the boiler water supplied to the boiler drum, And controlling the water supply valve to adjust the flow rate of the boiler water to be supplied to the boiler,
A measurement result of a conductivity meter for measuring the conductivity of the boiler water stored in the boiler drum, a measurement result of a second flow meter for measuring a flow rate of steam emitted from the boiler drum, and a flow rate of the boiler water blown from the boiler drum The flow rate of the boiler water blown from the boiler drum is adjusted so as to calculate the conductivity after a predetermined time elapses based on the measurement result of the third flow meter to be measured and to set the conductivity within the set range in accordance with the calculation result And controlling the blow valve.

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