JP6070414B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system including a boiler group having a plurality of boilers capable of burning by continuously changing a combustion rate.

  2. Description of the Related Art Conventionally, a boiler system has been proposed that includes a boiler group having a plurality of boilers that can be combusted at a plurality of staged combustion positions, and a control unit that controls the combustion state of the boiler group according to a required load. In addition, a so-called proportional control type boiler system has been proposed in which the amount of steam generated is controlled by continuously increasing or decreasing the combustion amount of the boiler.

  In a boiler system having a plurality of boilers, it is necessary to appropriately control the combustion state of each boiler according to a required load. In recent years, several attempts have been made to appropriately control the number of boilers to be burned. For example, in Patent Document 1, a boiler is divided into three load zones, a load increase zone, an optimum operation load zone, and a load decrease load zone, and the boiler is burned when burning in the load increase load zone. A control method of a proportional control boiler has been proposed in which the number of boilers is increased and the number of boilers to be burned is reduced when the boiler is burning in a load reduction zone.

Japanese Patent Laid-Open No. 11-132405

  By the way, the method proposed in Patent Document 1 is based on the premise that the efficiency characteristics of all the boilers are the same, and when applied to a boiler system having different efficiency characteristics for each boiler, the appropriate control is not necessarily performed. However, further improvements were required.

  This invention is made | formed in view of such a problem, and aims at providing the boiler system which can control the number of combustion of a boiler appropriately in a boiler system provided with the several boiler from which an efficiency characteristic differs. .

  The present invention is a boiler system including a boiler group including a plurality of boilers capable of burning by continuously changing a combustion rate, and a control unit that controls a combustion state of the boiler group according to a required load. The eco-operation zone, which is in the range of the combustion rate where the boiler efficiency is higher than a predetermined value, is set for each of the boilers, and the control unit is configured to burn the boilers in a combustion state. A determination unit that determines whether the rate has reached the upper limit value of the eco-operation zone set in the boiler, and the determination unit determines that the combustion rate of the boiler has reached the upper limit value of the eco-operation zone And an increase control unit that increases the number of boilers to be burned by one when the engine is fired.

  Further, the determination unit determines whether or not the combustion rate of the boiler in the combustion state has reached a lower limit value of the eco-operation zone set in the boiler, and the control unit is configured to perform the boiler operation by the determination unit. When it is determined that the combustion rate of the engine has reached the lower limit value of the eco-operation zone, a reduction controller for reducing the number of boilers to be burned by one may be further provided.

  Further, the determination unit determines whether or not a combustion rate of a boiler in a combustion state has reached a predetermined combustion rate lower than a lower limit value of the eco-operation zone set in the boiler, and the control unit When the determination unit determines that the combustion rate of the boiler has reached the predetermined combustion rate, it may further include a reduction control unit that reduces the number of boilers to be burned by one.

  In addition, when the number of boilers to be burned is increased by the increase control unit, the control unit permits a decrease in the number of boilers to be burned by the reduction control unit on condition that a predetermined condition is satisfied. It is good also as providing a reduction base permission part.

  In this case, the predetermined condition is that the combustion rate of all boilers in a combustion state rises to a first threshold within the range of the eco-operation zone, or a second threshold outside the range of the eco-operation zone. It is preferable that either decrease to

  The control unit may further include an output control unit that burns a plurality of boilers in a combustion state at a uniform combustion rate when the number of boilers to be burned is increased.

  ADVANTAGE OF THE INVENTION According to this invention, in a boiler system provided with the several boiler from which an efficiency characteristic differs, the number of combustion of a boiler can be controlled appropriately.

It is a figure showing the outline of the boiler system of one embodiment of the present invention. It is a figure which shows the outline of a boiler group. It is a figure which shows the outline of a boiler group. It is a functional block diagram which shows the structure of a control part. It is explanatory drawing which shows the operation example at the time of an increase control part increasing the number of boilers. It is explanatory drawing which shows the operation example at the time of a reduction controller reducing the number of boilers. It is explanatory drawing which shows the operation example when a reduction | decrease stand permission part permits the number reduction.

Hereinafter, preferred embodiments of the boiler system of the present invention will be described with reference to the drawings.
First, the overall configuration of the boiler system 1 of the present invention will be described with reference to FIG.
The boiler system 1 includes a boiler group 2 including a plurality of (five) boilers 20, a steam header 6 that collects steam generated in the plurality of boilers 20, and steam that measures the pressure inside the steam header 6. A pressure sensor 7 and a number control device 3 having a controller 4 that controls the combustion state of the boiler group 2 are provided.

The boiler group 2 generates steam to be supplied to the steam use facility 18.
The steam header 6 is connected to a plurality of boilers 20 constituting the boiler group 2 via a steam pipe 11. A downstream side of the steam header 6 is connected to a steam use facility 18 via a steam pipe 12.
The steam header 6 collects and stores the steam generated in the boiler group 2, thereby adjusting the pressure difference and pressure fluctuation of the plurality of boilers 20, and supplying the steam whose pressure is adjusted to the steam using facility 18. Supply.

  The vapor pressure sensor 7 is electrically connected to the number control device 3 via the signal line 13. The steam pressure sensor 7 measures the steam pressure inside the steam header 6 (steam pressure generated in the boiler group 2), and sends a signal (steam pressure signal) related to the measured steam pressure via the signal line 13. It transmits to the control apparatus 3.

  The number control device 3 is electrically connected to the plurality of boilers 20 through the signal line 16. The number control device 3 controls the combustion state of each boiler 20 based on the steam pressure inside the steam header 6 measured by the steam pressure sensor 7. Details of the number control device 3 will be described later.

The above boiler system 1 can supply the steam generated in the boiler group 2 to the steam using equipment 18 via the steam header 6.
The load required in the boiler system 1 (required load) is the amount of steam consumed in the steam using facility 18. The number control device 3 determines the fluctuation of the steam pressure inside the steam header 6 corresponding to the fluctuation of the steam consumption based on the steam pressure (physical quantity) inside the steam header 6 measured by the steam pressure sensor 7. It calculates and controls the combustion state of each boiler 20 which comprises the boiler group 2. FIG.

  Specifically, if the required load (steam consumption) increases due to an increase in demand for the steam use facility 18 and the amount of steam supplied to the steam header 6 (output steam amount described later) is insufficient, the steam header 6 The internal vapor pressure will decrease. On the other hand, if the demand load (steam consumption) decreases due to a decrease in the demand for the steam use facility 18 and the amount of steam supplied to the steam header 6 becomes excessive, the steam pressure inside the steam header 6 increases. Become. Therefore, the boiler system 1 can monitor the fluctuation of the required load based on the fluctuation of the vapor pressure measured by the vapor pressure sensor 7. Then, the boiler system 1 calculates a necessary steam amount that is a steam amount required according to the consumed steam amount (required load) of the steam using facility 18 based on the steam pressure of the steam header 6.

  Here, the several boiler 20 which comprises the boiler system 1 of this embodiment is demonstrated. FIG.2 and FIG.3 is a figure which shows the outline of the boiler group 2 which concerns on this embodiment.

As shown in FIG. 2, the boiler 20 of the present embodiment is composed of a proportional control boiler capable of burning by continuously changing the combustion rate.
The proportional control boiler is a boiler whose combustion rate can be continuously controlled at least in the range from the minimum combustion state S1 (for example, the combustion state of 20% of the combustion rate) to the maximum combustion state S2. The proportional control boiler adjusts the combustion rate, for example, by controlling the opening degree (combustion ratio) of a valve that supplies fuel to the burner and a valve that supplies combustion air.

  Also, the continuous control of the combustion rate means that the calculation or signal in the local control unit 22 described later is a digital method and is handled in stages (for example, the output (combustion rate) of the boiler 20 is in increments of 1%). Even when the output is controlled).

In this embodiment, the change of the combustion state between the combustion stop state S0 and the minimum combustion state S1 of the boiler 20 is controlled by turning on / off the combustion of the boiler 20 (burner). In the range from the minimum combustion state S1 to the maximum combustion state S2, the combustion rate can be continuously controlled.
More specifically, a unit steam amount U which is a unit of variable steam amount is set in the plurality of boilers 20. Thus, the boiler 20 can change the steam amount in units of the unit steam amount U in the range from the minimum combustion state S1 to the maximum combustion state S2.

The unit steam amount U can be appropriately set according to the steam amount (maximum steam amount) in the maximum combustion state S2 of the boiler 20, but from the viewpoint of improving the followability of the output steam amount to the necessary steam amount in the boiler system 1. It is preferably set to 0.1% to 20% of the maximum steam amount of 20, and more preferably set to 1% to 10%.
The output steam amount indicates the steam amount output by the boiler group 2, and this output steam amount is represented by the total value of the steam amounts output from each of the plurality of boilers 20.

  Further, as shown in FIG. 3, the boiler 20 of the present embodiment is set with an eco operation zone Z that is set corresponding to the range of the combustion rate in the case of burning at a predetermined range of boiler efficiency. Although the eco-operation zone Z can be set arbitrarily, in this embodiment, the range of the combustion rate in which the boiler efficiency (the thermal efficiency of the boiler 20) is higher than the first threshold (for example, 98%) is eco-friendly. The operation zone Z is set.

Here, in this embodiment, the range of the eco-operation zone Z is different in each of the plurality of boilers 20. As an example, in this embodiment, the eco operation zone Z of the No. 1 boiler is set to a range of 40 to 70% combustion rate, the eco operation zone Z of the No. 2 boiler is set to a range of 50 to 80% combustion rate, The eco operation zone Z of the No. 3 boiler is set in the range of 30 to 60% combustion rate, the eco operation zone Z of the No. 4 boiler is set in the range of 40 to 60% combustion rate, and the eco operation zone Z of the No. 5 boiler is set. Is set in the range of 30 to 80%.
In this embodiment, the efficiency characteristics of all of the No. 1 boiler to the No. 5 boiler are made different. However, the present invention is not limited to this, and one or a plurality of boilers 20 having different efficiency characteristics may be mixed.

  Returning to FIG. 2, the priority order is set for each of the plurality of boilers 20. The priority order is used to select the boiler 20 that performs a combustion instruction or a combustion stop instruction. The priority order can be set, for example, using an integer value so that the lower the numerical value, the higher the priority order. As shown in FIG. 2, when priority levels “1” to “5” are assigned to each of the No. 1 to No. 5 boilers, the No. 1 boiler has the highest priority, and the No. 5 boiler priority. Is the lowest. In the normal case, this priority order is changed at predetermined time intervals (for example, 24 hour intervals) under the control of the control unit 4 described later.

The boiler 20 demonstrated above is provided with the boiler main body 21 in which combustion is performed, and the local control part 22 which controls the combustion state of the boiler 20, as shown in FIG.
The local control unit 22 changes the combustion state of the boiler 20 according to the required load. Specifically, the local control unit 22 controls the combustion state of the boiler 20 based on the number control signal transmitted from the number control device 3 via the signal line 16.
Further, the local control unit 22 transmits a signal used in the number control device 3 to the number control device 3 via the signal line 16. Examples of the signal used in the number control device 3 include an actual combustion state of the boiler 20 and other data.

Next, details of the number control device 3 will be described.
Based on the vapor pressure signal from the vapor pressure sensor 7, the number control device 3 calculates the required combustion amount of the boiler group 2 according to the required load and the combustion state of each boiler 20 corresponding to the required combustion amount, The number control signal is transmitted to the boiler 20 (local control unit 22). As shown in FIG. 1, the number control device 3 includes a storage unit 5 and a control unit 4.

  The storage unit 5 stores information on instructions given to each boiler 20 under the control of the number control device 3 (control unit 4), information on the combustion state received from each boiler 20, and eco-operation of a plurality of boilers 20. Information relating to the setting of the zone Z, information relating to the setting of the unit steam amount U of the plurality of boilers 20, information relating to the setting of the priority order of the plurality of boilers 20, information relating to the setting change (rotation) of the priority order, and the like are stored.

  The control unit 4 gives various instructions to each boiler 20 via the signal line 16 and receives various data from each boiler 20 to control the combustion state and priority order of the five boilers 20. . When each boiler 20 receives a signal for changing the combustion state from the number control device 3, it controls the boiler 20 according to the instruction.

Such a control unit 4 controls the number of boilers 20 to be burned based on the eco-operation zone Z set for each of the plurality of boilers 20. That is, when the combustion rate of the plurality of boilers 20 in the combustion state increases until the eco-operation zone Z is removed, the control unit 4 increases the number of boilers 20 to be burned, and the combustion rate of the plurality of boilers 20 in the combustion state. When the vehicle descends until it goes out of the eco-operation zone Z, the number of boilers 20 to be burned is reduced.
Therefore, the control unit 4 has the configuration shown in FIG. FIG. 4 is a functional block diagram showing the configuration of the control unit 4. As shown in FIG. 4, the control unit 4 includes an output control unit 41, a determination unit 42, an increase control unit 43, a decrease control unit 44, and a decrease permission unit 45.

  The output control unit 41 controls the combustion amount of the boiler 20 so that the amount of steam corresponding to the required load is output from the boiler group 2. Here, when there are a plurality of boilers 20 in a combustion state, the output control unit 41 basically burns all the boilers 20 at a uniform combustion rate.

The determination unit 42 determines whether or not the combustion rate of the boiler 20 in the combustion state has reached the upper limit value of the eco-operation zone Z. Here, since the eco-operation zone Z is set to a different range for each boiler 20, the determination unit 42 determines whether the combustion rate has reached the upper limit value of the eco-operation zone Z for each boiler 20 in the combustion state. Determine whether.
Further, the determination unit 42 determines, for each boiler 20 in the combustion state, whether or not the combustion rate of the boiler 20 in the combustion state has reached the lower limit value of the eco-operation zone Z.

  When the determination unit 42 determines that the combustion rate of all the boilers 20 in the combustion state has reached the upper limit value of the eco-operation zone Z, the additional controller 43 combusts the boilers 20 in the combustion stop state S0. And the number of boilers 20 to be burned is increased by one.

  The reduction controller 44 stops the combustion of the boiler 20 in the combustion state when the determination unit 42 determines that the combustion rate of all the boilers 20 in the combustion state has reached the lower limit value of the eco-operation zone Z. The number of boilers 20 to be burned is reduced by one.

  Here, with reference to FIG.5 and FIG.6, the increase / decrease in the number of the boilers 20 made to burn by the control part 4 is demonstrated. FIG. 5 shows an operation example when the increase control unit 43 increases the number of boilers 20, and FIG. 6 shows an operation example when the decrease control unit 44 decreases the number of boilers 20.

With reference to FIG. 5 (A), only No. 1 boiler is burning among the five boilers 20, and the other boilers 20 have stopped burning. At this time, when the required load increases, the output control unit 41 increases the combustion rate of the No. 1 boiler in the combustion state.
As a result, as shown in FIG. 5B, when the combustion rate of the No. 1 boiler in the combustion state increases until reaching the upper limit value of the eco-operation zone Z set in the No. 1 boiler, the determination unit 42 It is determined that the combustion rate of all boilers 20 in the state has reached the upper limit value of the eco-operation zone Z.

  And with the determination by the determination part 42, as shown in FIG.5 (C), the stand extension control part 43 starts combustion of the No. 2 boiler with the highest priority among the boilers 20 in the combustion stop state S0, The number of boilers 20 to be burned is increased by one. When the number of boilers 20 to be burned is increased by 1, the output control unit 41 burns the boiler 20 in a combustion state at a uniform combustion rate. That is, in FIG. 5C, the No. 1 and No. 2 boilers in the combustion state are burning at a uniform combustion rate.

  Thereafter, when the required load increases, the output control unit 41 increases the combustion rate of the No. 1 and No. 2 boilers in the combustion state. At this time, the output control unit 41 uniformly burns the No. 1 and No. 2 boilers until the combustion rate of one of the No. 1 and No. 2 boilers in the combustion state reaches the upper limit value of the eco-operation zone Z. Burn at a rate. In the present embodiment, the upper limit value of the No. 1 boiler is 70%, and the upper limit value of the No. 2 boiler is 80%. Therefore, as shown in FIG. 5D, the output control unit 41 has a combustion rate of 70% (1 The No. 1 and No. 2 boilers are burned at a uniform combustion rate until the upper limit of the No. 1 boiler).

Thereafter, when the required load further increases, the combustion rate of the No. 1 boiler will be out of the eco-operation zone Z when the combustion rate of the No. 1 boiler is increased. Therefore, the output control unit 41 sets the combustion rate of the No. 1 boiler. While fixing at 70% (the upper limit value of the No. 1 boiler), the combustion rate of the No. 2 boiler is increased to follow the required load.
As a result, when the combustion rate of the No. 2 boiler reaches the upper limit value of the eco-operation zone Z set in the No. 2 boiler as shown in FIG. 5 (E), the determination unit 42 determines that all the boilers 20 in the combustion state Is determined to have reached the upper limit value of the eco-operation zone Z.

  And with the determination by the determination part 42, as shown in FIG.5 (F), the additional control part 43 starts combustion of the No. 3 boiler with the highest priority among the boilers 20 in the combustion stop state S0, The number of boilers 20 to be burned is increased by one. At this time, the output control unit 41 burns the boiler 20 in the combustion state at a uniform combustion rate.

Thus, in the boiler system 1 of this embodiment, when the combustion rate of all the boilers 20 in a combustion state reaches the upper limit value of the set eco-operation zone Z, the number of boilers 20 to be burned is increased by one. At this time, since the eco-operation zones Z set in the boiler 20 are different, the combustion rate for increasing the number of boilers 20 to be burned differs depending on the type of the boiler 20 in the combustion state.
Specifically, when the number of boilers 20 in the combustion state is two, that is, No. 1 and No. 2 boilers, the combustion rate of the boiler group 2 is the upper limit (70%) of the No. 1 boiler and the upper limit of the No. 2 boiler ( 80%), the number of boilers 20 to be burned increases. On the other hand, when the number of boilers 20 in the combustion state is two, ie, No. 1 and No. 3 boilers, the combustion rate of the boiler group 2 is the upper limit (70%) of the No. 1 boiler and the upper limit of the No. 2 boiler (60%). When the sum reaches 130%, the number of boilers 20 to be burned increases.

  As a result, even when the boilers 20 having different efficiency characteristics and different eco-operation zones Z are mixed, the number of boilers 20 burned can be increased appropriately while the boilers 20 are burned efficiently.

Subsequently, referring to FIG. 6 (A), among the five boilers 20, the No. 1, No. 2 and No. 3 boilers are combusted, and the other boilers 20 are stopped. Thereafter, when the required load decreases, the output control unit 41 lowers the combustion rate of the No. 1, No. 2, and No. 3 boilers in the combustion state. At this time, the output control unit 41 is in the first state until the combustion rate of the boiler 20 in any of the No. 1, No. 2 and No. 3 boilers in the combustion state reaches the lower limit value of the eco-operation zone Z. The No. 2 and No. 3 boilers are burned at a uniform combustion rate.
In this embodiment, the lower limit value of the No. 1 boiler is 40%, the lower limit value of the No. 2 boiler is 50%, and the lower limit value of the No. 3 boiler is 30%. Therefore, as shown in FIG. The part 41 burns the No. 1, No. 2 and No. 3 boilers at a uniform combustion rate up to a combustion rate of 50% (lower limit of No. 2 boiler).

After that, if the required load further decreases, the combustion rate of the No. 2 boiler will fall out of the eco-operation zone Z if the combustion rate of the No. 2 boiler is lowered. While fixed at 50% (lower limit of the No. 2 boiler), the combustion rates of the No. 1 and No. 3 boilers are lowered to follow the required load. At this time, the output control unit 41 uniformly burns the No. 1 and No. 3 boilers until the combustion rate of any one of the No. 1 and No. 3 boilers reaches the lower limit of the eco-operation zone Z. Burn at a rate.
As a result, as shown in FIG. 6C, the combustion rates of the No. 1 and No. 3 boilers fall to 40%, which is the lower limit value of the No. 1 boiler.

After that, when the required load further decreases, the combustion rate of the No. 1 boiler falls outside the eco-operation zone Z when the combustion rate of the No. 1 boiler is lowered, so the output control unit 41 sets the combustion rate of the No. 1 boiler. While fixed at 40% (lower limit value of the No. 1 boiler), the combustion rate of the No. 3 boiler is lowered to follow the required load.
As a result, as shown in FIG. 6 (D), when the combustion rate of the No. 3 boiler reaches the lower limit value of the eco-operation zone Z set in the No. 3 boiler, the determination unit 42 sets all the boilers 20 in the combustion state. Is determined to have reached the lower limit of the eco-operation zone Z.

  And with the determination by the determination part 42, as shown in FIG.6 (E), the reduction | decrease control part 44 stops the combustion of the No. 3 boiler with the lowest priority among the boilers 20 in a combustion state, and makes it burn. Decrease the number of boilers 20 by one. As the number of boilers 20 to be burned decreases by one, the output control unit 41 increases the combustion rates of the No. 1 and No. 2 boilers in the combustion state by the combustion rate of the No. 3 boiler.

Thereafter, when the required load further decreases, the output control unit 41 lowers the combustion rate of the No. 1 and No. 2 boilers in the combustion state. Even in this case, the output control unit 41 does not operate the first and second units until the combustion rate of any one of the first and second boilers in the combustion state reaches the lower limit of the eco-operation zone Z. Unit No. boiler is burned at a uniform burning rate. In the No. 1 boiler and the No. 2 boiler, the combustion rate of the No. 2 boiler reaches the lower limit first as shown in FIG. 6 (F).
When the required load further decreases after FIG. 6 (F), the output control unit 41 lowers the combustion rate of the No. 1 boiler until it reaches the lower limit value while fixing the combustion rate of the No. 2 boiler. . Thereafter, when the combustion rate of the No. 1 boiler decreases to the lower limit value, the determination unit 42 determines that the combustion rates of all the boilers 20 in the combustion state have reached the lower limit value of the eco-operation zone Z, and the reduction control unit 44 reduces the number of boilers 20 to be burned by one.

  Thus, as in the case of increasing the number of boilers 20 to be burned, the threshold for reducing the number of boilers 20 to be burned can be varied depending on the type of boiler 20 in the combustion state, The number of boilers 20 to be burned can be reduced while the boilers 20 are burned efficiently.

By the way, when increasing the number of the boilers 20 to burn, the combustion rate of the boiler 20 which has already been in a combustion state decreases by the amount of the combustion rate of the boiler 20 that newly starts combustion. At this time, depending on the decreasing combustion rate, the increase in the number of units by the increase control unit 43 and the decrease in the number of units by the decrease control unit 44 will be repeated.
As an example, referring to FIGS. 5B and 5C, the combustion rate of the No. 1 boiler that burned at the upper limit of the eco-operation zone Z before the start of the combustion of the No. 2 boiler is the same as that of the No. 2 boiler. With the start of combustion, the combustion rate has dropped to a lower combustion rate than the lower limit value of the eco-operation zone Z. At this time, since the combustion rates of the No. 1 and No. 2 boilers are lower than the lower limit value of the eco-operation zone Z, the No. 2 boiler that has started combustion may be immediately stopped. Therefore, the control unit 4 is supposed to provide a certain restriction on the decrease in the number of boilers 20 to be burned by the reduction controller 44.

Returning to FIG. 4, when the number of boilers 20 to be combusted is increased by the additional controller 43, the lowering permission unit 45 causes the boiler 20 to be combusted by the reduced controller 44 on condition that a predetermined condition is satisfied. Allow a decrease in the number of cars.
Here, as the predetermined condition, the combustion rate of all the boilers 20 in the combustion state rises to the first threshold value in the eco-operation zone Z (hereinafter may be referred to as “first condition”), or Any of the combustion rates of all boilers 20 in the combustion state falling to a second threshold value that is lower than the lower limit value of the eco-operation zone Z (hereinafter sometimes referred to as “second condition”) can be used. .

  Here, with reference to FIG. 7, permission to reduce the number of boilers 20 to be burned by the control unit 4 will be described. FIG. 7 shows an operation example when the reduction base permission unit 45 permits the number reduction.

  With reference to FIG. 7 (A), the combustion rate of the No. 1 and No. 2 boilers in the combustion state with the start of combustion of the No. 2 boiler falls below the lower limit value of the eco-operation zone Z and is out of the eco-operation zone Z. .

When the required load increases after increasing the number of boilers 20 to be burned, the combustion rate of the boiler 20 in the combustion state increases. The first condition is used for permitting reduction when the combustion rate increases. With reference to FIG. 7 (B), when the combustion rate that has deviated from the eco-operation zone Z increases to the eco-operation zone Z as the number of units increases, the reduction-permission permission unit 45 permits it.
In order to prevent repeated increase / decrease, the first threshold value in the eco-operation zone Z is preferably a combustion rate higher than the lower limit value of the eco-operation zone Z. At this time, since the lower limit value of the eco-operation zone Z is different for each boiler 20, the first threshold value in the eco-operation zone is also different for each boiler 20. And the reduction | decrease stand permission part 45 permits the reduction | decrease of a number, when all the combustion rates of the boiler 20 in a combustion state rise to the 1st threshold value in the eco-operation zone Z.

Further, when the required load decreases after increasing the number of boilers 20 to be burned, the combustion rate of the boiler 20 in the combustion state decreases. While preventing increase / decrease repetition, when the required load decreases more than necessary, it is required to reduce the number of boilers 20 to be burned. The second condition is used for permitting a decrease when the combustion rate decreases. With reference to FIG. 7C, when the combustion rate of the boiler 20 in the combustion state decreases to a second threshold value lower than the lower limit value of the eco-operation zone Z, permission by the reduction base permission unit 45 is performed.
Note that the second threshold value lower than the lower limit value of the eco-operation zone Z can be arbitrarily set, and for example, a combustion rate (20%) corresponding to the minimum combustion state S1 can be used.

  According to the boiler system 1 of this embodiment demonstrated above, there exist the following effects.

  In the boiler system 1 of the present embodiment, the eco operation zone Z is individually set for each of the plurality of boilers 20, and the combustion rate of the boiler 20 in which the determination unit 42 is in the combustion state is the upper limit value of the eco operation zone Z. If it determines with having reached | attained, the stand increase control part 43 will increase the number of the boilers 20 made to burn by one. Thereby, even if it is a case where the boiler 20 with which the efficiency characteristic differs and the eco-operation zone Z is mixed, the number of combustion of the boiler 20 can be increased appropriately, burning the boiler 20 efficiently.

  In the boiler system 1, if the determination unit 42 determines that the combustion rate of the boiler 20 in the combustion state has reached the lower limit value of the eco-operation zone Z, the reduction controller 44 determines the number of boilers 20 to be burned. Decrease by 1 unit. Thereby, the combustion number of the boilers 20 having different characteristics can be appropriately reduced while efficiently burning the boilers 20.

  Moreover, in the boiler system 1, the reduction | decrease stand permission part 45 of the number of the boilers 20 made to burn by the reduction | decrease stand control part 44 is provided on condition that a predetermined condition is satisfied when the number of the boilers 20 to burn is increased. Allow reduction. Thereby, it can prevent repeating the increase / decrease in the number of the boilers 20 to burn.

  At this time, in the boiler system 1, as a predetermined condition, the combustion rate of all the boilers 20 in the combustion state rises to the first threshold value within the range of the eco-operation zone Z, or is outside the range of the eco-operation zone Z. Any one of the following is adopted. Thereby, the reduction | decrease permission by the reduction | decrease base permission part 45 can be performed appropriately with respect to the fluctuation | variation (increase / decrease) of the required load after increasing the number of the boilers 20 to burn.

  Moreover, in the boiler system 1, the output control part 41 burns the several boiler 20 in a combustion state with a uniform combustion rate, when the number of the boilers 20 burned is increased. Thereby, the combustion rate of the several boiler 20 in a combustion state can be equalized, and the pressure stability in the boiler system 1 whole can be improved.

  The preferred embodiment of the boiler system 1 of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and can be modified as appropriate.

For example, in the above embodiment, when the combustion rate of the boiler 20 in the combustion state reaches the lower limit value of the eco operation zone Z, the reduction controller 44 reduces the number of boilers 20 to be burned by one. The threshold value for reducing the number of combustion is not limited to the lower limit value of the eco-operation zone Z. That is, when the combustion rate of the boiler 20 in the combustion state reaches a predetermined combustion rate lower than the lower limit value of the eco-operation zone Z, the reduction controller 44 may reduce the number of boilers 20 to be burned by one. Good.
In this case, the determination unit 42 determines whether or not the combustion rate of the boiler 20 in the combustion state has reached a predetermined combustion rate that is lower than the lower limit value of the eco-operation zone Z. When it is determined by 42 that the combustion rate of the boiler 20 in the combustion state has reached a predetermined combustion rate, this can be realized by reducing the number of boilers to be burned by one. Although the predetermined combustion rate can be set arbitrarily, it is preferable that the combustion rate is higher than the above-described second threshold value used by the reduction base permission unit 45 under the second condition in order to prevent repeated increase / decrease.

  For example, in the said embodiment, although this invention was applied to the boiler system provided with the boiler group 2 which consists of the five boilers 20, it is not restricted to this. That is, the present invention may be applied to a boiler system including a boiler group including six or more boilers, or may be applied to a boiler system including a boiler group including two boilers.

DESCRIPTION OF SYMBOLS 1 Boiler system 2 Boiler group 20 Boilers 3 Number control device 4 Control part 41 Output control part 42 Judgment part 43 Increase base control part 44 Decrease base control part 45 Reduction base permission part

Claims (5)

A boiler having a plurality of boilers including boilers having different efficiency characteristics that can be burned by continuously changing a combustion rate, and a control unit that controls a combustion state of the boiler group according to a required load. A system,
In the plurality of boilers,
An eco-operation zone, which is a combustion rate range in which the boiler efficiency is higher than a predetermined value, is set for each boiler, and
The controller is
For each boiler in the combustion state, it is determined whether the combustion rate has reached the upper limit value of the eco-operation zone set in the boiler , and the combustion rate is set in the boiler for each boiler in the combustion state A determination unit that determines whether or not a predetermined combustion rate that is equal to or lower than a lower limit value of the eco-friendly driving zone is reached ;
When the determination unit determines that the combustion rate of all boilers in the combustion state has reached the upper limit value of the eco-operation zone set in each boiler, the number of boilers to be burned is increased by one. An additional control unit,
Reduction control for reducing the number of boilers to be burned by one when the determination unit determines that the combustion rate of all boilers in the combustion state has reached the predetermined combustion rate set for each boiler And
When the number of boilers to be burned is increased by the increase control unit, a reduction allowance unit that permits a decrease in the number of boilers to be burned by the reduction control unit, provided that a predetermined condition is satisfied,
Boiler system equipped with. The boiler system according to claim 1, wherein the predetermined combustion rate is a lower limit value of the eco-operation zone set in the boiler. The boiler system according to claim 1, wherein the predetermined combustion rate is a combustion rate lower than a lower limit value of the eco-operation zone set in the boiler. Wherein the predetermined condition, the combustion rate of all of the boiler in the combustion state, rises to the first threshold value within the range of the eco zone set at each boiler, or that is set to each of the boiler The boiler system according to claim 1 , wherein the boiler system is any one of decreasing to a second threshold value outside the range of the eco-operation zone. The controller is
An output control unit for burning a plurality of boilers in a combustion state at a uniform combustion rate when the number of boilers to be burned is increased,
The boiler system according to claim 1 or 2, further comprising:

Images