JP2016057019A - Boiler device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boiler device capable of performing continuous water feed control that prevents overshooting or undershooting of a target water level, even when a combustion amount stage is abruptly changed.SOLUTION: A boiler device 1 having an economizer 3 is provided, in which, when a water level detected by a water level detection sensor 25 is out of a first proper water level region, which is calculated on the basis of a plurality of parameters measured by a first supply water temperature sensor 32 and including temperature of water supplied to a boiler can body, a control unit 10 intermittently controls a second water supply control section 102 to start or stop water supply until the water level detected by the water level detection sensor 25 settles within a second proper water level region, which is calculated on the basis of a plurality of parameters measured by a second supply water temperature sensor 33 and including temperature of water supplied to the economizer 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to water supply control in a boiler apparatus having a water heater (hereinafter also referred to as “economizer”) for heating water supplied to a boiler.

  Conventionally, as described in Patent Document 1, continuous water supply control is known as water supply control. In continuous water supply control, for example, the target water level is calculated based on parameters including the combustion amount of the boiler, the internal pressure of the can body, the feed water temperature, and the electrical conductivity of the feed water, so that the boiler water level becomes the calculated target water level. In addition, the feed water pump and the feed water flow rate adjustment valve are controlled to continuously supply the feed water to the boiler.

More specifically, the combustion amount of the boiler, the internal pressure of the can body, the feed water temperature and the electrical conductivity, and the water level inside the water pipe have the following relationships (1) to (4).
(1) Since the evaporation becomes more active as the combustion amount of the boiler is higher, the boiler controls the water level to be lower as the combustion rate is higher.
(2) Since the evaporation becomes more active as the internal pressure of the can body is lower, the boiler controls the water level to be lower as the internal pressure of the can body is lower.
(3) Since the evaporation becomes more active as the feed water temperature is higher, the boiler controls the water level to be lower as the feed water temperature is higher.
(4) Evaporation (foaming of the water level in the water pipe) becomes more active as the electric conductivity of the feed water is higher, so the boiler controls to lower the water level as the electric conductivity of the feed water is higher. .

JP 2012-47383 A

  In a boiler apparatus having an economizer, for example, when the target water level is calculated based on parameters including the combustion amount of the boiler, the internal pressure of the can body, the feed water temperature to the can body, and the electrical conductivity of the feed water, and continuous feed water control is performed. The following issues arise.

If one of the parameters described above, for example, the combustion amount changes greatly, the target water level may be greatly shifted, which may cause a problem in continuous water supply control.
For example, when the load is reduced and the combustion stage is changed from high combustion to low combustion, there is a considerable difference in water level between the water level at high combustion and the target water level at low combustion. For this reason, in order to raise the water level in a can, a control part controls a water supply pump and a water supply flow rate adjustment valve, and increases water supply amount rapidly. If the amount of water supply increases, the amount of water passing through the economizer increases, so that the temperature of the water supply to the can body becomes lower than that in the steady state, and the calculated target water level increases. By doing so, an overshoot of the target water level occurs, and the water level is raised to a target water level that is higher than the target water level in the steady state. Thereafter, when a steady state is reached, a return delay for returning to the target water level at the steady state occurs.

  Conversely, when the load increases and the combustion stage changes from low combustion to high combustion, the control unit controls the water supply pump and the water supply flow rate adjustment valve to lower the water level rapidly in order to lower the water level in the can. It will be. When the amount of water supply decreases, the amount of water staying in the economizer increases, so that the temperature of the water supply to the can body becomes higher than in the steady state, and the calculated target water level decreases. By doing so, an undershoot of the target water level occurs, the water level is lowered to a target water level lower than the target water level at the steady state, and there is a possibility that adverse effects such as pressure drop due to boiler standby may occur. Further, when a steady state is reached, a return delay for returning to the target water level at the steady state occurs.

  Thus, in a boiler device having an economizer, for example, when the combustion amount changes greatly, the supply water temperature to the can body changes abruptly, resulting in overshoot or undershoot of the target water level, and continuous water supply control. It will cause trouble.

  The present invention has been made in view of the problems as described above, and in a boiler apparatus having an economizer, for example, even when the combustion amount stage is suddenly changed, overshoot of the target water level or By preventing undershoot, it is possible to prevent overheating and pressure drop due to boiler standby, and to provide a boiler device that can perform continuous water supply control so that it can shift to the target water level in a steady state without delay. To do.

In order to achieve the above object, the boiler apparatus of the present invention is configured as follows.
(1) A boiler apparatus of the present invention is a boiler apparatus that generates steam from feed water by burning fuel, and a combustion gas generated by burning the fuel into a can body and feed water supplied to the can body A feed water heater that heats the can body through the feed water heater, a water level detector that detects a water level inside the can body, and the feed water heater in the feed water line A first feed water temperature measuring unit that measures the temperature of the feed water supplied to the can body between the can body and the can body, and is supplied to the feed water heater upstream of the feed water heater in the feed water line A second feed water temperature measuring unit that measures the temperature of the feed water; a feed water flow rate adjusting unit that is disposed upstream of the feed water heater in the feed water line and that regulates the flow rate of the feed water supplied to the feed water heater; Water supply A control unit that controls the amount adjustment unit, wherein the control unit is based on a plurality of parameters, wherein the water level detected by the water level detection unit includes the temperature of the feed water measured by the first feed water temperature measurement unit When the water level is within the first appropriate water level range including the first target water level calculated in the above, the water supply flow rate adjusting unit is continuously controlled so that the water level detected by the water level detecting unit becomes the first target water level. A first water supply control unit and a first water level detected by the water level detection unit include a first target water level calculated based on a plurality of parameters including the temperature of the water supply measured by the first water supply temperature measurement unit. When the water level is outside the proper water level range, the water level detected by the water level detection unit includes the second target water level calculated based on a plurality of parameters including the temperature of the feed water measured by the second feed water temperature measurement unit. Until it snaps into the second proper level range, characterized in that it comprises a second water supply control unit for intermittently controlling the feed water flow adjusting unit to supply or stop water supply.

  According to the boiler apparatus having the economizer of the present invention, for example, the stage of the combustion amount is suddenly changed from low combustion to high combustion, or from high combustion to low combustion, and a significant target water level fluctuation occurs. However, it is possible to prevent overshoot or undershoot of the target water level, prevent overheating and prevent pressure drop due to boiler standby, and perform continuous water supply control so that the target water level can be shifted to the steady state without delay.

(2) It is preferable that the first water supply control unit performs PI control or PID control of the water supply flow rate adjustment unit so that the water level detected by the water level detection unit becomes the first target water level.

(3) After the predetermined time has elapsed after the water level detected by the water level detection unit falls within the second appropriate water level range including the second target water level by the second water supply control unit, It is preferable to perform control by the water supply control unit.
By doing so, time until the feed water temperature is stabilized can be secured.

(4) It is preferable that the upper limit and the lower limit of the second appropriate water level range are respectively equal to the second target water level.

According to the present invention, in the boiler apparatus having an economizer, the control unit includes a plurality of water levels detected by the water level detection unit, the temperature of the water supplied to the can being measured by the first water supply temperature measurement unit. When the water level is outside the first appropriate water level range including the first target water level calculated based on the parameters, the water level detected by the water level detection unit is measured by the second water supply control unit by the second water supply temperature measurement unit. Intermittent control is performed to supply or stop the feed water until it falls within the second appropriate water level range including the second target water level calculated based on a plurality of parameters including the temperature of the feed water supplied to the feed water heater. As a result, for example, even if the stage of the combustion amount is suddenly changed from low combustion to high combustion, or from high combustion to low combustion, and the target water level fluctuates significantly, Together prevent-shoot or under-shoot, it is possible to enable the pressure drop prevention by preventing overheating and boilers standby.
And when a boiler will be in a steady state, it can return to continuous water supply control, without a delay in the target water level at the time of a steady state.

1 is an overall configuration diagram of a boiler device 1 according to a first embodiment. It is a block diagram which shows the functional structure of the control part 10 of the boiler apparatus 1 which concerns on 1st Embodiment. It is a figure which shows an example of the table of the appropriate water level of 1st Embodiment. It is a flowchart which shows operation | movement of the boiler apparatus 1 which concerns on 1st Embodiment.

[Configuration of First Embodiment]
Hereinafter, a boiler device according to a first embodiment of the present invention will be described with reference to the drawings.
The boiler apparatus 1 heats the feed water W1 supplied via the feed water line L1, and generates the steam W2.
As shown in FIG. 1, the boiler device 1 according to the first embodiment includes a can body 20, an economizer 3 as a feed water heater, and a pressure sensor 30 as a steam pressure detection unit that detects the steam pressure of the can body 20. A water level sensor 31 as a water level detection unit for detecting the water level inside the can body 20, a first feed water temperature sensor 32 as a first feed water temperature measurement unit for measuring the feed water temperature at the can body inlet, and an economizer entrance A second feed water temperature sensor 33 as a second feed water temperature measuring unit for measuring feed water temperature, an electrical conductivity sensor 34 for measuring the electrical conductivity of can water, a feed water pump 8, and a feed water flow rate as a feed water flow rate adjusting unit. The adjustment valve 9, the control unit 10, and the storage unit 11 are provided.

  Further, the boiler apparatus 1 includes a water supply line L1, a fuel supply line L2, and a steam supply line L3. The “line” in the present specification is a general term for lines capable of flowing a fluid such as a flow path, a radial path, and a pipeline.

  Each line is provided with devices such as various valves, various sensors, check valves, orifices, strainers and the like as necessary, but the illustration is omitted as appropriate in FIG.

  The water supply line L <b> 1 is a line that supplies the water supply W <b> 1 toward the can body 20 via the economizer 3. The upstream end of the water supply line L1 is connected to a water supply source (not shown). The downstream end of the water supply line L <b> 1 is connected to the water supply inlet of the can body 20.

The economizer 3 is a facility that is provided in the water supply line L <b> 1 and preheats the water supply W <b> 1 before being supplied to the can body 20 by waste heat of exhaust gas generated when fuel burns in the can body 20.
The water supply line L1 is provided with a water supply pump 8 and a water supply flow rate adjustment valve 9. Furthermore, the 1st water supply temperature sensor 32, the 2nd water supply temperature sensor 33, and the electrical conductivity sensor 34 are provided in the water supply line L1.

  The 1st feed water temperature sensor 32 is arrange | positioned downstream from the economizer 3 in the water supply line L1, and the water supply W1 which distribute | circulates the downstream from the economizer 3 in the water supply line L1 (water supply W1 supplied to the boiler 2 from the economizer 3). Detect the temperature. In other words, the 1st feed water temperature sensor 32 detects the temperature of the feed water W1 which distribute | circulates between the economizer 3 and the can 20 in the feed water line L1. The first feed water temperature sensor 32 is connected to the feed water line L1 at the connection portion J1. The connecting portion J1 is disposed between the economizer 3 and the can body 20. The first feed water temperature sensor 32 is electrically connected to the control unit 10. The temperature of the water supply W1 detected by the first water supply temperature sensor 32 (hereinafter also referred to as “water supply temperature at the inlet of the can”) is transmitted to the control unit 10 as a detection signal.

  The second feed water temperature sensor 33 is disposed upstream of the economizer 3 in the feed water line L1 and feeds water W1 that circulates upstream of the economizer 3 in the feed water line L1 (water feed W1 supplied from the feed water line 1 to the economizer 3). ) Temperature. In other words, the second feed water temperature sensor 33 detects the temperature of the feed water W1 at the entrance of the economizer 3 in the feed water line L1. The second feed water temperature sensor 33 is connected to the feed water line L1 at the connection portion J2. The connection portion J2 is disposed between the water supply flow rate adjustment valve 9 and the economizer 3. The second feed water temperature sensor 33 is electrically connected to the control unit 10. The temperature of the water supply W1 detected by the second water supply temperature sensor 33 (hereinafter also referred to as “economizer inlet water supply temperature”) is transmitted to the control unit 10 as a detection signal.

  The electrical conductivity sensor 34 is a sensor that measures the electrical conductivity of can water. The electrical conductivity value of the can water measured by the electrical conductivity sensor 34 is transmitted to the control unit 10 as a detection signal.

  The feed water pump 8 is a device that sucks in the feed water W <b> 1 and discharges it toward the can body 20. A motor (not shown) provided in the water supply pump 8 is electrically connected to the control unit 10 and is controlled and driven based on a control signal from the control unit 10. The feed water pump 8 may be configured such that the flow rate can be adjusted by being driven by being controlled by the inverter frequency.

  The water supply flow rate adjustment valve 9 is a valve that is disposed downstream of the water supply pump 8 and upstream of the economizer 3 in the water supply line L1 and can adjust the flow rate of the water supply W1 supplied to the economizer 3. The feed water flow rate adjustment valve 9 is electrically connected to the control unit 10. The valve opening degree of the feed water flow rate adjustment valve 9 (the opening degree of the valve element) is controlled by a drive signal from the control unit 10.

The can 20 includes a lower header, a water tube, an upper header, a burner, and the like (all not shown).
The upper header is a hollow container formed in an annular shape. The upper end of each water pipe communicates with the upper header. The upstream end of the steam supply line L3 is connected to the upper end of the upper header. The steam W2 generated in the plurality of water pipes is sent to the steam supply line L3 through the upper header. A pressure sensor 30 is connected to the upper header as a steam pressure detection unit that detects the steam pressure in the upper header. The steam supply line L3 is a line for supplying the load W 5 with the steam W2 generated in the water pipe. The downstream end of the steam supply line L <b> 3 is connected to the load device 5.

  A burner (not shown) is a combustion apparatus that burns fuel (liquid or gas). A fuel supply line L2 is connected to the burner. The fuel supply line L2 is a line for supplying fuel delivered from a fuel supply source (not shown) to the burner.

  The water level sensor 31 is a device that detects the water level inside the can 20. The water level sensor 31 is electrically connected to the control unit 10. The water level inside the can 20 detected by the water level sensor 31 (hereinafter also referred to as “water level Hd”) is transmitted to the control unit 10 as a detection signal.

  The load device 5 is a device (for example, a heat exchanger) that is operated by the steam W2 supplied from the boiler 2. The steam W2 used in the load device 5 is deprived of heat and condensed, and is discharged as drain W (not shown).

  The control unit 10 determines the combustion state of the fuel in the can body 20 based on the amount of steam consumed by the load device 5, the pressure of the steam detected by the pressure sensor 30, and the like (for example, step value control). In the case of a boiler, the position is set to one of N positions such as 1 to 3 stages, or in the case of a proportional control boiler, a range from a minimum combustion state to a maximum combustion state) and a combustion stop state.

The control unit 10 includes a first water supply control unit 101 and a second water supply control unit 102.
The first water supply control unit 101 calculates the first target water level based on a plurality of parameters including the water supply temperature at the inlet of the can whose water level detected by the water level sensor 31 is measured by the first water supply temperature sensor 32. When the water level falls within the first appropriate water level range, the water supply flow rate adjustment valve 9 is continuously controlled so that the water level detected by the water level sensor 31 becomes the first target water level.
The second water supply control unit 102 includes a first water level detected by the water level sensor 31 including a first target water level calculated based on a plurality of parameters including the temperature of the water supply measured by the first water supply temperature sensor 32. When the water level is outside the proper water level range, the water level detected by the water level sensor 31 includes the second target water level calculated based on a plurality of parameters including the water supply temperature at the economizer entrance measured by the second water supply temperature sensor 12. The feed water flow rate adjustment valve 9 is intermittently controlled so as to supply or stop the feed water until it falls within the second appropriate water level range.

  The storage unit 11 stores, for example, appropriate water level tables or approximate functions corresponding to a first water supply control unit 101 and a second water supply control unit 102 described later, respectively.

The control unit 10 and the storage unit 11 can be configured by a microprocessor (not shown) including a CPU and a memory. In this case, the storage unit 11 can be configured by a memory.
The microprocessor incorporates an integrated timer unit (hereinafter also referred to as “ITU”) that manages time measurement and the like.
When the various programs are executed by the microprocessor, the microprocessor functions as the control unit 10 including the first water supply control unit 101 and the second water supply control unit 102.

Next, water supply control of the boiler device 1 according to the first embodiment will be described.
The control unit 10 controls the load factor (combustion amount of the boiler 1) by the first water supply control unit 101, the internal pressure of the can body 20 measured by the pressure sensor 30, and the electricity of the can water measured by the electrical conductivity sensor 34. Based on the conductivity and the feed water temperature at the can inlet measured by the first feed water temperature sensor 32, a first appropriate water level range including the first target water level inside the water pipe is calculated.
Here, the first appropriate water level range may be a range in which a value obtained by adding a differential value set in advance to the first target water level is an upper limit value, and a value obtained by subtracting the differential value is a lower limit value.

More specifically, the first water supply control unit 101 can calculate the first target water level as follows, for example.
When the boiler device 1 is a step value control boiler, for example, as illustrated in FIG. 3, the storage unit 11 has a specific load factor (for example, a low combustion position, a middle combustion position, and a high combustion position), and a specific For each electrical conductivity, the proper water level having the target pressure corresponding to each internal pressure in the row and each feed water temperature in the column at the intersection of the column and the row, with the internal pressure of the can body 20 as the row and the feed water temperature as the column. Remember the table.

Specifically, the storage unit 11 stores a table of appropriate water levels corresponding to a predetermined internal pressure of the can body and a predetermined water supply temperature at a plurality of load factors (for example, a low combustion position, a middle combustion position, and a high combustion position). Store for each specific electrical conductivity.
For example, as illustrated in FIG. 3, the storage unit 11 stores tables 111 a to 111 d of appropriate water levels at the low combustion position.
Each table 111a-111d has shown the value of the appropriate water level corresponding to the internal pressure and water supply temperature of a can body in case electrical conductivity is 100, 200, 300, and 400 mS / m in order.

Similarly to the tables 111a to 111d, the storage unit 11 stores a table of appropriate water levels at the middle combustion position and a table of appropriate water levels at the high combustion position.
As with the tables 111a to 111d, the appropriate water level table at the middle combustion position and the appropriate water level table at the high combustion position are the internal pressure of the can body and the water supply when the electrical conductivity is 100, 200, 300 and 400 mS / m. The value of the appropriate water level corresponding to the temperature is shown.

  The first water supply control unit 101 has a plurality of (for example, four) appropriate values that approximate the internal pressure of the can body 20 measured by the pressure sensor 30 and the water supply temperature at the can body entrance measured by the first water supply temperature sensor 32. The water level is selected from a table of appropriate water levels corresponding to the combustion positions, and the appropriate water level corresponding to the internal pressure and the feed water temperature of the can 20 is selected for each electrical conductivity using linear interpolation from the selected plurality of appropriate water levels. Ask. The first water supply control unit 101 obtains the appropriate water level in the electrical conductivity measured by the electrical conductivity sensor 34 from the obtained appropriate water level for each specific electrical conductivity using linear interpolation, and determines the appropriate water level. Calculated as one target water level.

  When the boiler device 1 is a proportional control boiler, the storage unit 11 stores the combustion amount of the can 20, the feed water temperature measured by the first feed water temperature sensor 32, and the can measured by the electrical conductivity sensor 34. An approximation function for calculating an appropriate water level is stored with the electrical conductivity of water and the pressure of the steam inside the can body 20 measured by the pressure sensor 30 as inputs.

  The first water supply control unit 101 includes the combustion amount of the can 20, the water supply temperature at the inlet of the can measured by the first water supply temperature sensor 32, the electrical conductivity of the can water measured by the electrical conductivity sensor 34, and the pressure From the steam pressure inside the can body 20 measured by the sensor 30, an appropriate water level is obtained using an approximate function stored in the storage unit 11, and the appropriate water level is calculated as the first target water level.

Next, the control unit 10 determines whether or not the water level inside the can 20 detected by the water level sensor 31 falls within the first appropriate water level range, and the water level falls within the first appropriate water level range. The water supply flow rate adjustment valve 9 is continuously controlled by the first water supply control unit 101 so that the water level detected by the water level sensor 31 becomes the first target water level.
At this time, the first water supply control unit 101 can perform PI control or PID control of the water supply flow rate adjustment valve 9 so that the water level detected by the water level sensor 31 becomes the first target water level.

  Note that the continuous control of the feed water flow rate (including PI control or PID control) is not limited to the continuous control of the feed water flow rate by the feed water flow rate adjustment valve 9. For example, the feed water flow rate may be continuously controlled by the feed water pump 8 capable of adjusting the flow rate. Further, the feed water flow rate may be continuously controlled by the feed water pump 8 and the feed water flow rate adjusting valve 9 which can adjust the flow rate. It is arbitrarily selected whether to use the water supply amount adjustment by the water supply flow rate adjustment valve 9, the water supply amount adjustment by the water supply pump 8 capable of adjusting the flow rate, or the water supply amount adjustment by the water supply pump 8 and the water supply flow rate adjustment valve 9 capable of adjusting the flow rate. Can be set.

When the water level inside the can 20 does not fall within the first appropriate water level range, the control unit 10 can measure the load factor (combustion amount of the boiler 1) and the pressure sensor 30 by the second water supply control unit 102. Based on the internal pressure of the body 20, the electrical conductivity of the can water measured by the electrical conductivity sensor 34, and the feed water temperature of the economizer 3 inlet measured by the second feed water temperature sensor 12, the second target water level inside the water pipe is determined. A second appropriate water level range is calculated.
Here, the second appropriate water level range can be a range in which a value obtained by adding a differential value set in advance to the second target water level is an upper limit value, and a value obtained by subtracting the differential value is a lower limit value.

The procedure for calculating the second target water level inside the water pipe in the second water supply control unit 102 is the same as the procedure for calculating the first target water level inside the water pipe in the first water supply control unit 101. Detailed description will be omitted.
In addition, since the measurement location of feed water temperature differs, the table of the appropriate water level for calculating an appropriate water level, and the approximate function for calculating an appropriate water level differ from that of the 1st water supply control part 101. FIG.

Next, the second water supply control unit 102 determines whether the water level detected by the water level sensor 31 is within the second appropriate water level range or out of the range.
When the water level detected by the water level sensor 31 exceeds the upper limit of the second appropriate water level range, the second water supply control unit 102 supplies water so as to stop water supply until the water level falls within the second appropriate water level range. The flow regulating valve 9 is controlled to be turned off.
In addition, when the water level detected by the water level sensor 31 is equal to or lower than the lower limit of the second appropriate water level range, the second water supply control unit 102 supplies the supply water until the water level falls within the second appropriate water level range. The adjustment valve 9 is turned on.
Thus, the control part 10 performs intermittent control of water supply by the 2nd water supply control part 102, when a water level does not fall in the 2nd appropriate water level range.

When the water level detected by the water level sensor 31 is within the second appropriate water level range, or when the water level detected by the water level sensor is within the second appropriate water level range by the intermittent water supply control by the second water supply control unit 102 The control unit 10 shifts to continuous water supply control (including PI control or PID control) by the first water supply control unit 101 after a predetermined time has elapsed.
The predetermined time is for securing a time until the can body water supply temperature is stabilized.

By doing so, the control unit 10 can change the target combustion level even if the stage of the combustion amount is suddenly changed from low combustion to high combustion, or from high combustion to low combustion, and the target water level fluctuates significantly. While preventing overshoot or undershoot of the water level, it is possible to prevent overheating and pressure drop due to boiler standby.
And when a boiler will be in a steady state, it can return to continuous water supply control (PI control or PID control) without a delay in the target water level at the time of a steady state.

  Next, operation | movement of the control part 10 in the boiler apparatus 1 of 1st Embodiment is demonstrated, referring FIG.

  In step ST1, the control unit 10 causes the first water supply control unit 101 to calculate a first appropriate water level range including the first target water level inside the water pipe based on a plurality of parameters including the water supply temperature at the can inlet.

  In step ST2, the control unit 10 determines whether or not the water level inside the can 20 detected by the water level sensor 31 falls within the first appropriate water level range calculated in step ST1. When it falls within the first appropriate water level range (YES), the process proceeds to step ST3. When it does not fall within the first appropriate water level range (NO), the process proceeds to step ST4.

  In step ST3, the control unit 10 continuously controls the feed water flow rate adjustment valve 9 and the like so that the water level detected by the water level sensor 31 becomes the first target water level by the first water supply control unit 101 (PI control or PID). Control. Thereafter, the process returns to step ST1.

  In step ST4, the control unit 10 causes the second water supply control unit 102 to calculate a second appropriate water level range including the second target water level inside the water pipe based on a plurality of parameters including the water supply temperature at the economizer inlet.

  In step ST5, the control part 10 determines whether the water level inside the can 20 detected by the water level sensor 31 is within the second appropriate water level range calculated in step ST4 by the second water supply control part 102. . When the water level falls within the second appropriate water level range (YES), the process proceeds to step ST8. When the water level exceeds the upper limit of the second appropriate water level range, the process proceeds to step ST6. When the water level is equal to or lower than the lower limit of the second appropriate water level range, the process proceeds to step ST7.

  In step ST <b> 6, the control unit 10 uses the second water supply control unit 102 to turn off the water supply flow rate adjustment valve 9 so as to stop the water supply until the water level falls within the second appropriate water level range. When the water level falls within the second appropriate water level range, the process proceeds to ST8.

  In step ST <b> 7, the control unit 10 causes the second water supply control unit 102 to turn on the water supply flow rate adjustment valve 9 so as to supply water until the water level falls within the second appropriate water level range. When the water level falls within the second appropriate water level range, the process proceeds to ST8.

  In step ST8, the control unit 10 returns to step ST1 after a predetermined time has elapsed.

  According to the boiler device 1 according to the first embodiment described above, for example, the following effects can be obtained.

  According to the boiler apparatus 1 having the economizer in the first embodiment, at a normal time, the water level detected by the water level sensor 31 by the first water supply control unit 101 is measured at the inlet of the can body measured by the first water supply temperature sensor 32. The feed water flow rate adjusting valve 9 and the like are continuously controlled (PI control or PID control) so that the first target water level is calculated based on a plurality of parameters including the temperature of the feed water. When the non-steady time is reached, for example, when the combustion amount stage is suddenly changed from low combustion to high combustion, or from high combustion to low combustion, and a large fluctuation in the target water level occurs (the water level changes to the first target water level). The water level detected by the water level sensor 31 by the second water supply control unit 102 includes a plurality of water supply temperatures at the economizer entrance measured by the second water supply temperature sensor 12. The feed water flow rate adjustment valve 9 and the like are intermittently controlled so as to be within the second appropriate water level range including the second target water level calculated based on the parameters, and the water level falls within the second appropriate water level range including the second target water level. Then, after the predetermined time has elapsed, the control is returned to the control by the first water supply control unit. For this reason, even if the target water level fluctuates significantly during non-stationary conditions, it is possible to prevent overshoot or undershoot of the target water level, prevent overheating, and prevent pressure drop due to boiler standby. Continuous water supply control can be performed so that the normal target water level can be shifted without delay.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be implemented in various forms.

  The exhaust gas that heats the economizer 3 is not limited to the exhaust gas from the boiler 2, and may be, for example, exhaust gas from an engine of another facility.

  In the first embodiment, the water supply flow rate adjusting unit is the water supply flow rate adjusting valve 9, but the water supply flow rate adjusting unit is not limited to a valve (valve). For example, the feed water flow rate adjusting unit may be a feed water pump 8 capable of adjusting the flow rate. Further, the feed water flow rate adjusting unit may be composed of a feed water pump 8 and a feed water flow rate adjusting valve 9 capable of adjusting the flow rate. It is arbitrarily selected whether to use the water supply amount adjustment by the water supply flow rate adjustment valve 9, the water supply amount adjustment by the water supply pump 8 capable of adjusting the flow rate, or the water supply amount adjustment by the water supply pump 8 and the water supply flow rate adjustment valve 9 capable of adjusting the flow rate. Can be set.

  In the first embodiment, the first water supply control unit 101 calculates the first target water level based on a plurality of parameters including the temperature of the water supply at the can inlet measured by the first water supply temperature sensor 32. You may make the said function independent from the 1st water supply control part 101. FIG. Similarly, the second water supply control unit 102 calculates the second target water level based on a plurality of parameters including the temperature of the water supply at the economizer inlet measured by the second water supply temperature sensor 33. You may make it independent from the 2 water supply control part 102. FIG.

  In the first embodiment, the control unit 10 determines whether or not the water level inside the can 20 detected by the water level sensor 31 falls within the first appropriate water level range. It may be determined by

1 Boiler device 3 Economizer (feed water heater)
DESCRIPTION OF SYMBOLS 5 Load apparatus 8 Water supply pump 9 Water supply amount adjustment valve 10 Control part 101 1st water supply control part 102 2nd water supply control part 11 Storage part 20 Can 30 Pressure sensor 31 Water level sensor 32 1st water supply temperature sensor 33 2nd water supply temperature sensor 34 Electric conductivity sensor L1 Water supply line L2 Fuel supply line L3 Steam supply line W1 Water supply W2 Steam

Claims (4)

A boiler device that burns fuel to generate steam from feed water,
Can body,
A feed water heater for heating the feed water supplied to the can body with combustion gas generated by burning the fuel;
A water supply line for supplying water to the can through the water heater;
A water level detection unit for detecting the water level inside the can body;
A first feed water temperature measuring unit that measures a temperature of feed water supplied to the can body between the feed water heater and the can body in the feed water line;
A second feed water temperature measuring unit that measures the temperature of feed water supplied to the feed water heater on the upstream side of the feed water heater in the feed water line;
A water supply flow rate adjusting unit that is arranged upstream of the water supply heater in the water supply line and adjusts the flow rate of water supplied to the water supply heater,
A control unit for controlling the feed water flow rate adjustment unit,
The controller is
When the water level detected by the water level detection unit falls within the first appropriate water level range including the first target water level calculated based on a plurality of parameters including the temperature of the feed water measured by the first feed water temperature measurement unit A first water supply control unit that continuously controls the water supply flow rate adjustment unit such that the water level detected by the water level detection unit becomes the first target water level;
When the water level detected by the water level detection unit is outside the first appropriate water level range including the first target water level calculated according to the temperature of the feed water measured by the first feed water temperature measurement unit, the water level detection The supply water is supplied or stopped until the water level detected by the unit falls within the second appropriate water level range including the second target water level calculated based on the temperature of the water supply measured by the second water supply temperature measurement unit. A second water supply control unit that intermittently controls the water supply flow rate adjustment unit;
The boiler apparatus characterized by including.   The said 1st water supply control part performs PI control or PID control of the said water supply flow volume adjustment part so that the water level detected by the said water level detection part may become said 1st target water level. The boiler device described in 1.   The control unit performs the first water supply control after a predetermined time has elapsed after the water level detected by the water level detection unit falls within the second appropriate water level range including the second target water level by the second water supply control unit. The boiler device according to claim 1, wherein control is performed by a unit.   The boiler apparatus according to any one of claims 1 to 3, wherein an upper limit and a lower limit of the second appropriate water level range are equal to the second target water level, respectively.

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