JP2014206374A - Economizer controller, economizer, and boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economizer controller, an economizer, and a boiler capable of suppressing a gas phase from being generated in a liquid such as water supplied to a heating device such as the boiler or suppressing a state of the liquid in which the gas phase is nearly generated in the liquid, in a heat exchanger of the economizer for increasing the temperature of the liquid with combustion gas of the heating device.SOLUTION: An economizer controller, of an economizer 30 provided in a boiler 10, arranged in an air passage 17A discharging combustion gas G2 of the boiler 10, and including a heat exchanger increasing a temperature of the water W by implementing heat exchange between the water W and the combustion gas G2 when the water W passes through the heat exchanger, determines a state of water W supplied from a water supply unit 20 in the heat exchanger. The economizer controller comprises: a vibration sensor 51 detecting vibration to follow generation of air bubble in the heat exchanger; and state determining means for determining the state of the water W on the basis of the vibration detected by the vibration sensor 51.

Description

  The present invention relates to an economizer control device for judging the state of a liquid in a heat exchange part of an economizer that raises the temperature of a liquid supplied to a heating device such as a boiler with combustion gas of the heating device, and an economizer using the economizer control device And the boiler.

  Conventionally, in order to save energy in a heating device such as a boiler, for example, the water supplied to the heating device is circulated to a heat exchanging portion formed of a heat transfer tube such as a so-called Erofin tube in which a strip-shaped metal plate is spirally wound around the outer periphery of the pipe. An economizer that heat-exchanges this water with the combustion gas of the heating device to raise the temperature is widely used (for example, see Patent Document 1).

  For example, when water is supplied to a boiler via an economizer, the water temperature is generally adjusted by intermittent water supply control in which the water supply amount corresponding to the combustion amount is supplied at predetermined intervals. Moreover, it is suitable from an energy-saving viewpoint to supply water to a boiler by making it as high as possible in an economizer.

JP 2009-174780 A

However, according to the above water supply control, when the combustion amount of the boiler changes after the water supply is stopped, the water in the economizer may be overheated and boiled. The economizer may be deteriorated or damaged by water hammer.
Therefore, there is a technical request to suppress boiling of water or the like (liquid) in the economizer to suppress pressure loss or water hammer generation in the economizer.

  The present invention has been made in consideration of such circumstances, and a liquid such as water supplied to a heating device such as a boiler is converted into a liquid in a heat exchange part of an economizer that raises the temperature by combustion gas of the heating device. An object of the present invention is to provide an economizer control device, an economizer, and a boiler that can suppress the occurrence of gas or the approach of a gas phase.

In order to solve the above problems, the present invention proposes the following means.
The invention according to claim 1 is provided in a heating device that heats a liquid by burning fuel, and is disposed in an air passage that discharges combustion gas generated by burning the fuel, and is supplied from a supply unit. An economizer control device for determining the state of a liquid in the heat exchange part of an economizer comprising a heat exchange part that heats and exchanges heat with the combustion gas when a liquid passes through the air bubble in the heat exchange part Based on a detection unit that detects the generation and a signal input from the detection unit, at least one of the presence of the gas phase in the liquid and the state in which the liquid is closer to the gas phase than the set state It is characterized by comprising state determining means for determining

  The invention described in claim 6 is an economizer, and includes the economizer control device described in any one of claims 1 to 5.

  The invention described in claim 7 is a boiler, and includes the economizer described in claim 6.

According to the economizer control device, the economizer, and the boiler according to the present invention, since the state of the liquid in the heat exchange part of the economizer is detected by bubble generation in the heat exchange part, the presence of the gas phase in the liquid and the liquid in the heat exchange part It is possible to accurately detect whether the inside is closer to the gas phase than the set state.
As a result, pressure loss in the economizer and generation of water hammer can be suppressed, and as a result, reduction in efficiency in water supply to a heating device such as a boiler can be suppressed, and deterioration and breakage of the economizer can be suppressed.

  Invention of Claim 2 is the economizer control apparatus of Claim 1, Comprising: The said detection part consists of a vibration sensor which detects the vibration accompanying the bubble production | generation in the said heat exchange part, A state determination means, The determination is made based on the vibration detected by the vibration sensor.

  According to the economizer control device according to the present invention, the detection unit includes a vibration sensor that detects vibration associated with bubble generation in the heat exchange unit, and the state determination unit determines based on the vibration detected by the vibration sensor. The generation of bubbles in the heat exchange section can be detected in a wide range, and the generation of a gas phase in the heat exchange section can be detected efficiently regardless of the position of the vibration sensor, and the reliability of the gas phase detection Can be improved.

  Invention of Claim 3 is the economizer control apparatus of Claim 1, Comprising: The said detection part has an electrode bar and an ammeter which detect the electrical conductivity of the said liquid, A state determination means, The determination is made based on a change in current caused by bubbles generated in the heat exchange section adhering to the electrode rod.

According to the economizer control device according to the present invention, the detection unit includes the electrode rod and the ammeter for detecting the conductivity of the liquid, and the state determination unit includes the bubbles generated in the heat exchange unit attached to the electrode rod. Therefore, even if it is difficult to detect the gas phase using only the temperature sensor due to the rise and fall of the boiling point of the conductive liquid due to the pressure change in the heat exchange section, the pressure can be detected without detecting the pressure. Since the phase can be detected, the accuracy of detecting the gas phase can be improved.
Further, cavitation, air entrainment, and the like may occur, and bubbles generated regardless of the liquid temperature may be detected, and the reliability of the economizer control unit can be improved.

  A fourth aspect of the present invention is the economizer control device according to any one of the first to third aspects, wherein the determination means is configured such that the liquid is present in a gas phase in the liquid and the liquid. A signal is output when it is determined that at least one of the inside is closer to the gas phase than the set state.

  A fifth aspect of the present invention is the economizer control device according to any one of the first to fourth aspects, wherein the determination means is configured to determine whether the liquid is in a gas phase in the liquid and the liquid. The apparatus is characterized in that the flow rate of the liquid by the supply means is increased when at least one of the inside is closer to the gas phase than the set state is detected.

  According to the economizer control device, the economizer and the boiler according to the present invention, the pressure loss and water hammer in the economizer are suppressed, and consequently, the efficiency reduction in the water supply to the heating device such as the boiler is suppressed, and the economizer is prevented from being deteriorated or damaged. can do.

It is a longitudinal section showing a schematic structure of a boiler concerning a 1st embodiment of the present invention. It is a longitudinal cross-sectional view which follows the III-III line of the boiler which concerns on 1st Embodiment. It is a figure which shows schematic structure of the economizer which concerns on 1st Embodiment. It is a figure explaining the flow of the economizer control apparatus which concerns on a reference example. It is a figure explaining the detection part of the economizer control apparatus which concerns on 2nd Embodiment.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The temperature sensor 50 shown in FIGS. 1 and 3 and FIG. 4 relate to a reference example.
1 and 2 are diagrams for explaining a small once-through boiler 10 according to the first embodiment. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a transverse section taken along line III-III in FIG. The figure is shown.
The boiler 10 includes a housing 11, a can 12, a burner 16, a combustion gas discharge pipe 17, a blower 18, a fuel supply unit 19, a water supply unit 20, an economizer 30, and a control unit 40. The economizer 30 is provided in a discharge path (ventilation path) 17A of the combustion gas discharge pipe 17.

The can 12 includes a water tube group 13, a lower header 14A positioned below the water tube group 13, and an upper header 14B positioned above the water tube group 13. The water tube group 13 includes a plurality of inner water tubes 13A. And a plurality of outer water pipes 13B.
A combustion gas passage 12G is formed in the water tube group 13, and the combustion gas G2 moves from the burner 16 toward the combustion gas discharge tube 17 between the inner water tubes 13A. Moreover, the pressure sensor 7 is connected to the upper header 14B, and detects the pressure of the steam in the upper header 14B.

As shown in FIG. 1, each of the inner water pipe 13A and the outer water pipe 13B constituting the water pipe group 13 is disposed vertically between the lower header 14A and the upper header 14B, and the lower header 14A and the upper header 13B. It is connected to the header 14B so that water can pass therethrough.
A castable (refractory) 11A is disposed on the upper portion of the lower header 14A and the lower portion of the upper header 14B.

Further, as shown in FIG. 2, the water tube group 13 has a water tube wall portion 13C that partitions the housing 11 and the combustion gas passage 12G, and an inner water tube 13A is formed inside the water tube wall portion 13C. Are arranged.
The water pipe wall 13C is combusted with the outer water pipe 13B arranged from the burner 16 toward the combustion gas discharge pipe 17, the adjacent outer water pipes 13B, the inner wall of the casing on the outer water pipe 13B and the burner 16 side, and the outer water pipe 13B. The inner wall of the casing on the gas exhaust pipe 17 side is composed of connecting members 15 that connect each other, and a pair is arranged on the left and right sides of the combustion gas passage 12G.

The burner 16 is formed, for example, in a box shape having a nozzle portion 16A on the surface on the water tube group 13 side, and a plurality of nozzle holes are arranged in a planar shape in the nozzle portion 16A and premixed supplied by a blowing means The gas G1 is supplied to the nozzle portion 16A.
Further, the burner 16 can control the combustion state (for example, high combustion, low combustion) based on the pressure of the steam detected by the pressure sensor 7, for example.
In FIG. 1 and FIG. 2, the broken line portion extending from the nozzle portion 16A to the water tube group 13 side conceptually represents the flame generated by the nozzle portion 16A.

  The premixed gas G1 supplied to the nozzle portion 16A is injected and burned from the nozzle hole to become a high-temperature combustion gas G2, and the combustion gas G2 passes through the combustion gas passage 12G and flows into the water (liquid) in the water tube group 13. ) W is heated and then introduced into the economizer 30 through the discharge path 17A.

  The combustion gas discharge pipe 17 constitutes a discharge path 17A for discharging the combustion gas G2 to the outside of the boiler 10 and is connected to the end of the combustion gas path 12G. The discharge path 17A guides the combustion gas G2 to the economizer 30. It has become.

  The blower means 18 includes a blower 18A, an air supply passage 18B, and a damper 18C. The blower 18A transfers the combustion air A1 to the air supply passage 18B, and the fuel supplied from the combustion air A1 and the fuel supply unit 19 is supplied. The gas G0 is mixed in the supply passage 18B to become the premixed gas G1, and is supplied to the burner 16.

The blower 18A rotates the blower fan to supply the combustion air A1, and the blower 18A in this embodiment controls the number of rotations of the blower fan by an inverter corresponding to the combustion state of the burner 16 and burns it. The blast volume of the working air A1 is adjusted.
Further, the opening degree of the damper 18C can be controlled by a motor (not shown), and the amount of combustion air A1 can be adjusted together with the blower 18A or independently.

  The fuel supply unit 19 includes a fuel supply pipe 19A and a flow rate adjustment valve 19B. By controlling the flow rate adjustment valve 19B, an amount of fuel gas G0 corresponding to the combustion state of the burner 16 is supplied to the fuel supply pipe 19A. It comes to supply.

The water supply unit 20 includes a water supply line 21 connected to the water supply source S, a water quality measurement unit 22, a water supply pump 23, a flow rate adjustment valve 24, a flow meter 25, and a check valve 26, and an economizer 30 is provided. Via the water supply source S, water is supplied to the can body 12.
In this embodiment, the water supply pump 23 intermittently supplies a predetermined amount of water W set in advance at a predetermined water supply timing (water supply interval).

  As shown in FIG. 3, the economizer 30 uses the waste heat of the combustion gas G2 that has passed through the water tube group 13 to heat the water W supplied to the can body 12, thereby saving energy, The water W is caused to flow through the heat exchange unit 36 disposed in 17A, the heat of the combustion gas G2 is exchanged by the heat exchange unit 36, and the water W in the heat exchange unit 36 is heated. It is supplied to the lower header 14 </ b> A of the can body 12.

  The heat exchanging part 36 is connected to the heat transfer pipe 37 formed so as to allow water to pass therethrough, and a plurality of pipes that extend in a direction substantially orthogonal to the heat transfer pipe 37 with an interval through which the combustion gas G2 can pass. And a fin member 38 made of a heat radiating plate. Water W supplied and heated from the inlet 37A of the heat transfer tube 37 is discharged from the outlet 37B, and the discharged water W is guided to the lower header 14A. It is like that.

The control unit 40 controls the combustion amount of the boiler 10 and the amount of water W supplied to the can body 12 via the economizer 30, and includes an input unit 41, a memory 42, a calculation unit 43, A hard disk 44, an output unit 46, and a communication line 47 are provided. The input unit 41, the memory 42, the calculation unit 43, the hard disk 44, and the output unit 46 are connected to each other via a communication line 47 so that data and the like can be communicated with each other. .
The hard disk 44 stores a first database 45A and a second database 45B.

  The input unit 41 includes, for example, a data input device such as a keyboard (not shown) and can output settings and the like to the calculation unit 43. The pressure sensor 7, the water quality measurement unit 22, the flow meter 25, and the temperature sensor 50 are provided. And a signal line 48 </ b> A to output signals input from the pressure sensor 7, the water quality measurement unit 22, the flow meter 25, and the temperature sensor 50 to the calculation unit 43.

  The output unit 46 is connected to the blower 18A, the damper 18C, the flow rate adjustment valve 19B, the water supply pump 23, the flow rate adjustment valve 24 and the signal line 48B, and the signal output from the calculation unit 43 is sent to the blower 18A, the damper 18C, and the flow rate adjustment valve. It outputs to 19B, the feed water pump 23, and the flow regulating valve 24.

  The arithmetic unit 43 reads and executes a program stored in a storage medium (for example, ROM) of the memory 42, and based on the input from the input unit 41, the combustion amount of the boiler 10 and the water supply to the can body 12 While calculating quantity, the control amount with respect to the air blower 18A, the damper 18C, the flow regulating valve 19B, the feed water pump 23, and the flow regulating valve 24 is computed.

In the first database 45A, for example, numerical data indicating the relationship between the current pressure and the combustion amount for transferring the current pressure to the set pressure is stored in the form of a data table.
The computing unit 43 calculates a combustion amount for ensuring the set pressure from the pressure obtained based on the pressure signal from the pressure sensor 7 with reference to the first database 45A, and the blower 18A via the output unit 46. The combustion amount of the burner 16 is adjusted by controlling the damper 18C and the flow rate adjusting valve 19B.

The second database 45B includes, for example, parameters such as the combustion amount of the burner 16, the pressure of the boiler 10, the supply temperature of the water W supplied from the water supply unit 20, the blow amount of a blow line (not shown), and the water supply by the water supply unit 20 Numerical data indicating the relationship with the quantity is stored in the form of a data table.
The calculation unit 43 calculates the water supply amount with reference to the second database from the signal related to the parameter input from the input unit 41, and outputs the water supply amount to the water supply pump 23 and the flow rate adjustment valve 24 via the output unit 46. The water supply amount of the water supply unit 20 is controlled.

  The control unit 40 includes an economizer control unit (economizer control device). The economizer control unit includes a temperature sensor (detection unit) 50 and a determination unit (determination unit). It is determined whether or not the water W in the heat exchange unit 36 is in a state close to the gas phase.

  The temperature sensor 50 is disposed, for example, in the vicinity of the outlet 37B of the heat exchange unit 36, and detects the temperature of the water W in the economizer 30 as a physical characteristic. In the reference example, for example, a thermocouple is used. .

When the determination unit determines that the water temperature in the heat exchange unit 36 input from the temperature sensor 50 has reached, for example, 98 ° C. near the boiling point, the determination unit supplies (forcibly) the water supply pump 23 via the output unit 46. A drive signal is output, and the water temperature in the heat exchanging unit 36 is lowered by forcibly supplying water to the economizer 30 to suppress boiling of the water W in the heat exchanging unit 36. .
Thereafter, when the water temperature drops to a predetermined value, the normal intermittent control is resumed.

FIG. 4 is a flowchart showing an outline of the water supply control in the economizer control unit according to the reference hand. Hereinafter, the outline of the water supply control will be described based on FIG. 4.
1) First, intermittent water supply timing (for example, intermittent time), temperature sensor upper limit set temperature T1, and lower limit set temperature T2 are set (S1).
2) Next, it is determined whether the boiler 10 is in operation (S2). When the boiler 10 is in operation, the process proceeds to S3, and when it is not in operation, the control is terminated.
3) It is determined whether it is a water supply timing (S3). If it is the water supply timing, the process proceeds to S4, and if it is not the water supply timing, the process proceeds to S5.
4) The water supply pump 23 of the water supply unit 20 is driven to supply water to the can body 12 through the economizer 30 (S4).
5) The determination unit determines whether the temperature T detected by the temperature sensor 50 is equal to or higher than the upper limit set temperature T1 (S5). When the temperature T is equal to or higher than the upper limit set temperature T1, the process proceeds to S6.
6) The determination unit forcibly drives the water supply pump 23 of the water supply unit 20 to supply water to the heat exchange unit 36 regardless of the water supply timing (S6).
7) The determination unit determines whether the temperature T detected by the temperature sensor 50 is equal to or lower than the lower limit set temperature T2 (S7). If the temperature T is lower than the lower limit set temperature T2, the process proceeds to S2, and if the temperature T is not lower than the lower limit set temperature T2, the process proceeds to S5.
During operation, the above 2) to 7) are repeated.
It is assumed that the temperature T of the temperature sensor 50 does not exceed the upper limit set temperature T1 during normal intermittent water supply.

According to the economizer 30 and the boiler 10 according to the reference example, when the water temperature detected by the temperature sensor 50 approaches the boiling point, the control unit 40 forcibly supplies water to the economizer 30 and decreases the temperature of the water W in the heat exchange unit 36. Therefore, it is suppressed that the water W in the heat exchange part 36 rises above the upper limit set temperature T1.
As a result, the pressure loss in the economizer 30 and the occurrence of water hammer are suppressed, and as a result, it is possible to suppress the decrease in efficiency in water supply to a heating device such as a boiler, and the deterioration and breakage of the economizer.

Next, an economizer control unit (economizer control device) according to the first embodiment of the present invention will be described.
The economizer control unit according to the first embodiment is different from the economizer control unit according to the reference example in that the physical characteristic of detecting the state of the water W in the heat exchange unit 36 of the economizer 30 is within the heat exchange unit 36. This is because it is constituted by a vibration sensor 51 that detects vibrations associated with the generation of bubbles in FIG.

According to the economizer control unit using the vibration sensor 51, the generation of bubbles in the heat exchange unit 36 can be detected over a wide range. Regardless, the detection can be performed efficiently, and the reliability of the gas phase detection can be improved.
Moreover, since the vibration sensor 51 can be arrange | positioned on the outer side of the heat exchange part 36, it can attach easily.

Next, an economizer control unit (economizer control device) according to a second embodiment of the present invention will be described.
The economizer control unit according to the second embodiment is different from the economizer control unit according to the reference example in that the detection unit detects an electrical conductivity (physical characteristic) of the water W in the heat exchange unit 36. 52, ammeter 53, and the like.

  In the detection of the gas phase by the electrode rod 52, bubbles adhere to the surface of the electrode rod 52, the contact area with the water W decreases, the current flowing through the water W decreases, and the apparent conductivity decreases. In this method, the gas phase is detected and can be applied to a liquid having conductivity.

As shown in FIG. 5, for example, the electrode rod 52 is disposed in the heat transfer tube 37 of the heat exchanging unit 36 by being insulated from the heat transfer tube 37 by the insulating material 52 </ b> A, and contacts the water W in the heat transfer can 37. It is like that.
The electrode bar 52 is connected to a power source 54 (for example, a positive electrode) via an ammeter 53, and the other pole of the power source 54 is connected to the water W via a heat transfer tube 37 so as to be able to be energized.
Then, a voltage is applied between the electrode rod 52 and the heat transfer tube 37, and the energization state is monitored with the current value detected by the ammeter 53, and the conductivity between the electrode rod 52 and the heat transfer tube 37 is confirmed (determination). ).

According to the third economizer control unit, even if the boiling point of the water W rises and lowers due to a pressure change in the heat exchange unit 36 and it is difficult to detect the gas phase only with the water temperature detected by the temperature sensor 50, the pressure of the water W is reduced. Since the gas phase can be detected without detection, the detection accuracy of the gas phase can be improved.
In addition, cavitation, air entrainment, and the like may occur, and bubbles generated regardless of the water temperature may be detected, and the reliability of the economizer control unit can be improved.

The present invention is not limited to the first and second embodiments, and various modifications can be made without departing from the spirit of the invention.
For example, in the above embodiment, the case where the liquid heated in the boiler is the water W has been described. However, instead of the water W, for example, chemical substances such as oils, acids, alkaline solutions, solvents, etc. are applied. Also good.

Further, although the case where the heating device is the small once-through steam boiler 10 in which the combustion gas G2 flows substantially linearly from the burner 16 side toward the discharge path 17A has been described, the water pipe is annular in addition to the small once-through boiler. The present invention may be applied to boilers of various structures such as a multi-tube boiler arranged in the above, a furnace flue tube boiler, and a hot water heater that directly heats a heating tube with a burner.
Moreover, you may apply with respect to hot water boilers and water heaters other than a steam boiler.

Further, in the reference example, the case where the temperature sensor 50 is disposed in the vicinity of the outlet 37B of the heat exchanging unit 36 where the water temperature becomes the highest in the economizer 30 has been described. You may arrange.
Moreover, although the case where the temperature sensor 50 was a thermocouple was demonstrated, you may use well-known temperature sensors other than a thermocouple.

  Moreover, in the said embodiment, although the case where the water supply part 20 had the water supply pump 23 and the flow regulating valve 24 was demonstrated, even if it uses the water supply part of the structure which does not have the flow control valve 24, or another structure. Good.

  In the above embodiment, the case where the water supply pump 23 is intermittently controlled and the water supply pump 23 is forcibly supplied when the gas phase is detected has been described. However, the water supply pump 23 and the flow rate adjustment valve 24 perform the forced water supply. The flow rate may be adjusted.

Further, for example, the flow rate of the water supply may be controlled by continuous control of the water supply pump 23, the flow rate control by the water supply pump 23, the flow rate control by the water supply pump 23 and the flow rate control valve 24, and the flow rate control valve 24. It is possible to arbitrarily set which one of the flow control by the above is adopted.
Moreover, it is good also as a structure which outputs the signal which concerns on monitoring means, such as an alarm, instead of the forced water supply by the water supply pump 23 or adjustment of a water supply amount, or in addition to adjustment of a water supply amount.

  Further, in the above embodiment, the physical characteristics for detecting the liquid state (the presence of the gas phase, etc.) are the vibration sensor 51 for detecting the water temperature in the heat exchange unit 36 and the vibration generated in the heat exchange unit 36, The electrode rod 52 for detecting the electrical conductivity of the water W flowing in the economizer 30 has been described, but other physical characteristics capable of detecting the presence of the gas phase or that the liquid is approaching the gas phase, For example, it goes without saying that detection means for detecting transmission of ultrasonic waves, optical characteristics, and the like may be used.

  According to the economizer control device, the economizer, and the boiler according to the present invention, pressure loss in the economizer and generation of water hammer can be suppressed, so that it can be used industrially.

G0 Fuel gas G2 Combustion gas W Water (liquid)
10 Boiler (heating device)
17A Discharge path (ventilation path)
20 Water supply section (supply means)
23 Water supply pump 30 Economizer 36 Heat exchange part 40 Control part (Economizer control device, determination means)
50 Temperature sensor (detection unit)
51 Vibration sensor (detection unit)
52 Electrode bar (detector)
53 Ammeter (Detector)

Claims (7)

Provided in a heating device that burns fuel and heats the liquid;
A heat exchanging unit is disposed in a ventilation path for discharging combustion gas generated by combustion of the fuel, and heat-exchanges with the combustion gas to raise the temperature when the liquid supplied from the supply means passes. An economizer control device for judging the state of the liquid in the heat exchange part of an economizer,
A detection unit for detecting bubble generation in the heat exchange unit;
State determination means for determining at least one of the presence of the gas phase in the liquid and the state in which the liquid is closer to the gas phase than the set state based on a signal input from the detection unit. An economizer control device characterized by that. The economizer control device according to claim 1,
The detector is
It consists of a vibration sensor that detects vibration associated with bubble generation in the heat exchange part,
The state determination means is
An economizer control device that performs determination based on vibration detected by the vibration sensor. The economizer control device according to claim 1,
The detector is
An electrode rod for detecting the conductivity of the liquid and an ammeter;
The state determination means is
An economizer control device characterized in that determination is made based on a current change caused by bubbles generated in the heat exchange section adhering to the electrode rod. The economizer control device according to any one of claims 1 to 3,
The determination means is configured to output a signal when the liquid determines at least one of the existence of a gas phase in the liquid and the liquid being in a state closer to the gas phase than a set state. An economizer control device characterized by that. The economizer control device according to any one of claims 1 to 4,
When the determination unit detects at least one of the presence of the gas phase in the liquid and the state in which the liquid is closer to the gas phase than the set state, the liquid by the supply unit The economizer control device is configured to increase the flow rate of the economizer.   An economizer comprising the economizer control device according to any one of claims 1 to 5.   A boiler comprising the economizer according to claim 6.

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