JP2015161426A - boiler system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rapid reduction in pressure of a boiler system caused by displacement in generating steam at an increased boiler in a group of boilers constituted by proportional control type boilers.SOLUTION: A control part 4 instructs to start production of steam to a new boiler (an increased boiler) in the case that an amount of consumption of steam is increased and an increased state of a boiler 20 is judged and at the same time a lack of steam generated until a supplying of steam can be performed by the increased boiler 20 is supplemented by a steam supply boiler already being ignited, so that a rate of combustion at another steam supply boiler is increased and after that, when the increased boiler 20 starts to supply steam and it is inputted to a control of the number of boilers, this is controlled in such a way that it is transferred to a requisite amount of steam corresponding to a requested load without decreasing a rate of combustion of another steam supplying boiler by an amount corresponding to an amount of rate of combustion of the increased boiler 20 that enabled steam to be supplied.

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, as a boiler system that generates steam by burning a plurality of boilers, a so-called proportional control type boiler system that controls the generation amount of steam by continuously increasing or decreasing the combustion amount of the boiler has been proposed.
In such a boiler system, by controlling the number of boilers to be burned, steam corresponding to the amount of steam consumed by the steam-using facility is generated from the boiler group. That is, in the boiler system, when the steam consumption increases, by starting the combustion of the boiler in the combustion stopped state and increasing the number of boilers in the combustion state, the steam amount corresponding to the increased steam consumption is removed from the boiler group. It is supposed to be generated.

  Here, the boiler which has been in a combustion stopped state for a long time is cooled, and even if combustion is started, steam cannot be generated until the internal can water reaches the boiling temperature. Therefore, even if it increases the boiler to burn, the said boiler cannot be integrated in control according to the steam consumption of a steam using facility.

Therefore, in such a boiler system, when the combustion of a boiler in a combustion stop state is started, the other steaming boiler in the combustion generates the shortage that occurs until the boiler becomes steamable ( Backup) to compensate for the shortage of steam.
In recent years, attempts have been made to incorporate a boiler that has started combustion into control at an appropriate timing. For example, Patent Document 1 discloses that a boiler in a combustion stopped state is required to generate steam for the boiler. It is described that the combustion of the boiler is started at an optimal timing by performing the steaming time and the warm-up operation time earlier.

JP 2001-33001 A

  By the way, when the boiler that started combustion starts steaming, the steam generated from another steaming boiler instead of the boiler that started combustion becomes excessive, so the control unit generates from the boiler that started combustion. The combustion rate of the other steam boiler is reduced by the amount of steam to be used.

  That is, when steam consumption increases and it is determined that boilers can be increased, a new boiler is instructed to start steaming, and the combustion rate of the already-fired boiler is increased. The amount of combustion (burning rate) is changed.

(Conventional example)
Here, with reference to FIG. 4, the outline | summary of the backup control at the time of a can increase is demonstrated. In FIG. 4, all of the five boilers 20 have the same capacity, and are referred to as a No. 1 boiler, a No. 2 boiler, a No. 3 boiler, a No. 4 boiler, and a No. 5 boiler in order from the left boiler 20.

  When the consumed steam amount (required load) of the steam-using facility increases and the required steam amount reaches the increased reference steam amount, the control unit issues a steaming instruction to the boiler in a combustion stopped state. As shown in FIG. 4, at the time of “(1) Steaming instruction”, the control unit issues a steaming instruction to the No. 3 boiler among the No. 3 boiler to the No. 5 boiler in the combustion stopped state.

When the No. 3 boiler starts combustion based on the steaming instruction, the control unit determines whether or not the No. 3 boiler can supply steam based on the steam pressure of the steam generated from the No. 3 boiler. As shown in FIG. 4, it is assumed that the “No. 3 boiler” still cannot steam during “(2) Steaming”.
When the steaming instruction of the No. 3 boiler is not possible, the control unit generates steam from the No. 1 boiler and the No. 2 boiler that are already in a combustion state, instead of generating steam to be generated from the No. 3 boiler. Increase the combustion rate of Unit 1 and Unit 2 boilers. In addition, the control unit continuously sets the combustion rates of the No. 1 boiler and No. 2 boiler according to fluctuations in the amount of steam consumed (required load) of the steam using equipment 18 until the No. 3 boiler can be steamed. change.

  Thereafter, when the No. 3 boiler becomes steamable, the steam generated from the No. 1 and No. 2 boilers becomes excessive instead of the No. 3 boiler. At the time of “) Steaming start”, the combustion rate of the No. 1 and No. 2 boilers corresponding to the amount of steam generated from the No. 3 boiler is reduced. That is, the combustion rates of the No. 1 boiler and the No. 2 boiler are reduced by the combustion rate of the No. 3 boiler that can supply steam.

However, when the No. 3 boiler generates, for example, a combustion amount of 20% of the maximum combustion amount of the boiler, the combustion amount of 20% of the maximum combustion amount of the No. 3 boiler is replaced. Largely, the steaming judgment of whether the No. 3 boiler can be steamed becomes very severe. If the steaming judgment is off by several seconds and the combustion amount (combustion rate) is changed while the No. 3 boiler does not generate a combustion amount of 20% of the maximum combustion amount of the boiler, for example, the No. 3 boiler Due to the shortage of steam output, the boiler system will drop in pressure, impairing the stability of steam supply.
In this regard, Patent Document 1 does not disclose the above-described problems and countermeasures in the case where the combustion amount (combustion rate) is changed based on the steaming determination of the increased boiler.

  In the present invention, when steam consumption is increased and it is determined that a boiler can be increased, a new boiler (also referred to as “increased boiler”) is instructed to start steaming, and the increased boiler can supply steam. In order to compensate for the shortage that occurs until the steam boiler is already burning, increase the combustion rate of the steam boiler, and then determine that the boiler has started steaming and incorporate it into unit control In addition, the amount of combustion that became excessively large without reducing the combustion rate of the other boiler boilers, that is, without replacing the combustion rate (combustion rate), for the combustion rate of the additional boiler that became steamable Is controlled so as to shift to the required steam amount according to the required load. By doing so, it aims at providing the boiler system which can prevent the rapid pressure drop of a boiler system by the shift | offset | difference of the steaming judgment of a can boiler, and can maintain pressure stability.

  According to the present invention, a plurality of boilers capable of burning by continuously changing a combustion rate, a steam header in which steam generated by the plurality of boilers collects, and the plurality of boilers according to a required load from a load device. A control unit that controls the combustion state of the boiler, and the control unit sets the required steam amount to PI so as to keep the steam pressure value inside the steam header at the target pressure value with respect to fluctuations in steam consumption. Control of the combustion state of a steam supply boiler that supplies steam among a plurality of boilers so as to generate a steam amount calculation unit calculated by a control method or a PID control method and a necessary steam amount calculated by the steam amount calculation unit An output control unit, a steaming instruction unit for instructing steaming to start steaming for a boiler that is not steamed among the plurality of boilers according to a required load, and the steaming instruction unit A boiler that is instructed to steam is supplied A first determination unit that determines whether or not the boiler has become a boiler, and the output control unit includes a steam supply boiler among the plurality of boilers until the steam-instructed boiler becomes a steam supply boiler. By continuously changing the combustion rate according to the required load, the steam output follow-up control with respect to the required load is performed, and it is determined that the boiler instructed by the first determination unit has become a steam supply boiler. In this case, it is equivalent to the amount of steam generated from the steaming boiler that started steaming, without reducing the combustion rate of other steaming boilers, that is, without replacing the combustion amount (combustion rate), The present invention relates to a boiler system that incorporates a steam supply boiler into the control.

  The control unit includes a first correction unit that corrects a PID parameter in the PI control method or the PID control method when a steam pressure value inside the steam header exceeds a preset first pressure threshold value. It is preferable.

  Further, it is preferable that the first correction unit returns the PID parameter in the PI control method or the PID control method before replacement after a predetermined time has elapsed.

  The PID parameter may include a proportional band, an integration time, or a derivative time.

  In addition, when the difference between the steam pressure value inside the steam header and the target pressure value exceeds a second threshold, the control unit corrects the target pressure value to the steam pressure value inside the steam header. Then, the 2nd correction | amendment part which returns to the said target pressure value in steps over a transition time can be provided after that.

  According to the present invention, in a boiler group composed of proportional control boilers, the steam consumption increases, the boiler can be judged to increase, the new boiler is instructed to start steaming, and the boiler is When the combustion rate of the already-fired boiler is increased so that other steaming boilers generate (backup) the shortage that occurs before steaming is possible, combustion based on the steaming judgment of the additional boiler It eliminates the need to replace the amount, prevents a rapid pressure drop in the boiler system due to misregistration in the steaming of the additional boiler, and maintains pressure stability.

It is a figure showing the outline of the boiler system concerning the embodiment of the present invention. It is a figure which shows the outline of a boiler group. It is a functional block diagram which shows the structure of the control part which concerns on 1st Embodiment. It is a functional block diagram which shows the structure of the control part which concerns on 2nd Embodiment. It is a figure which shows the prior art example of the combustion state of a boiler group. It is a figure which shows an example of the combustion state of the boiler group which concerns on this invention. In the boiler system 1 which concerns on 2nd Embodiment, after correcting the value of target vapor pressure by a 2nd correction | amendment part, it is a figure which shows the outline which changes in steps over time and returns to the original target vapor pressure. In the boiler system 1 according to the second embodiment, when the difference between the steam pressure value inside the steam header 6 and the target pressure value exceeds a preset second threshold after incorporating the can boiler 20 into the unit control. It is a figure which shows transition of the header pressure.

(First embodiment)
Hereinafter, a first embodiment according to an embodiment 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 is a diagram showing an outline of the boiler group 2 according to the present embodiment.
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 for each of 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%.
Note that 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.

  A priority order is set for each of the 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 the priorities of “1” to “5” are assigned to the first to fifth units of the boiler 20, the first unit has the highest priority, and the fifth unit has the highest priority. 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.

  In the boiler group 2, an increase reference threshold and a stop reference threshold for determining the number of boilers to be burned are set. In the present embodiment, the increase reference steam amount is used as the increase reference threshold, and the stop reference steam amount is used as the stop reference threshold.

The increase reference steam amount is a reference steam amount for increasing the number of boilers to be combusted. When the necessary steam amount reaches (or becomes larger than) the increase reference steam amount, the stopped boiler 20 starts combustion. The number of boilers 20 increases.
Further, the stop reference steam amount is a reference steam amount for stopping the combustion of one of the boilers 20 in the combustion state, and the required steam amount reaches the stop reference steam amount (below or below). When it becomes smaller, the combustion of one of the boilers 20 in the combustion state is stopped.
These increase reference steam amount and stop reference steam amount can be set arbitrarily, and arbitrary information other than the increase reference steam amount and stop reference steam amount can be used as the increase reference threshold and stop reference threshold. Good.

For example, the combustion rate of the boiler 20 in the combustion state may be used as the stop reference threshold and the increase reference threshold.
When the combustion rate is used, the combustion rate of the boiler 20 in the combustion state is increased by a reference threshold (for example, 50% if there is one boiler 20 in the combustion state, 100% if two boilers, 150% or the like), the boiler 20 that has been stopped starts to burn, and the number of boilers 20 increases.
The same applies to the stop reference threshold. That is, the combustion rate of the boiler 20 in the combustion state is the stop reference threshold (for example, 50% when there are two boilers 20 in the combustion state, 100% when three boilers, 150% when four boilers, etc.) When it reaches, the boiler 20 which was burning stops combustion, and the number of the boilers 20 decreases.

The above boiler 20 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 includes information on instructions given to each boiler 20 under the control of the number control device 3 (control unit 4), information such as the combustion state received from each boiler 20, and combustion patterns of a plurality of boilers 20. Information on setting conditions, etc., target pressure values as setting conditions related to the steam pressure measured by the steam pressure sensor 7, setting information on the increase reference threshold and stop reference threshold for determining the number of boilers to be burned, a plurality of The information about the unit steam amount U set in the boiler 20, the information on the priority order setting of the plurality of boilers 20, the information on the setting related to the change (rotation) of the priority order, and the like are stored. As will be described later, at least two or more PID parameters in the PI control method or the PID control method can be 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.

(Normal control)
When the fluctuation of the consumed steam amount (required load) of the steam using facility 18 does not exceed the increase reference threshold value or does not fall below the stop reference threshold value, the control unit 4 determines the combustion rate based on the combustion rate of each of the plurality of boilers 20. Is selected, and the combustion rate of the selected boiler 20 is changed in units of unit steam amount U, for example. Moreover, the control part 4 can select the other boiler 20 further as needed, and can also change the combustion rate of this selected other boiler 20 by the unit steam amount U unit, for example.

(Backup control)
Here, when the consumed steam amount (required load) of the steam using facility 18 increases and the necessary steam amount reaches the increased reference steam amount, the control unit 4 determines that the boiler 20 in the combustion stop state S0 (hereinafter “increase boiler”). The combustion of the boiler 20 is also started, and the number of boilers 20 in the combustion state is increased. At this time, the can boiler 20 that has been in the combustion stop state S0 is cooled, and until the internal can water reaches the boiling temperature even if combustion is started by the control unit 4 being controlled to start combustion. The steam cannot be output, and the output steam amount output from the boiler group 2 is insufficient with respect to the consumed steam amount (required load) of the steam using facility 18. Therefore, the control unit 4 instructs the other steam supply boilers 20 that can output steam to output the shortage steam instead until the boiler can 20 can be steamed, So-called backup is performed to prevent steam shortage. That is, the combustion rate of the other steam supply boiler 20 that can output steam is continuously changed according to the fluctuation of the consumed steam amount (required load) of the steam using facility 18.

(Control after the start of steaming of an additional boiler)
When the controller 4 determines that the boiler increaser 20 has started steaming and incorporates it in the unit control, the controller 4 reduces the combustion rate of the other steam boilers by the combustion rate of the boiler increaser 20 that has started steaming. Without changing, that is, without changing the combustion amount (combustion rate), the combustion amount that has become excessively large is controlled so as to shift to the required steam amount according to the required load.

When the steam pressure value inside the steam header 6 exceeds the preset first pressure threshold value after the number of boilers 20 has been incorporated into the unit control, the control unit 4 determines the PID in the PI control method or the PID control method. The parameter can be corrected. Here, the PID parameter includes a proportional band, an integration time, or a derivative time.
In addition, the control part 4 can return to the PID parameter in PI control system before replacement or PID control system after predetermined time progress. Note that, instead of “after a predetermined time has elapsed”, when the deviation between the target pressure value and the steam pressure value inside the steam header 6 is equal to or less than a predetermined value, the control unit 4 determines the PI control method before replacement. Or you may make it return to the PID parameter in a PID control system.
By doing so, the pressure stability can be maintained without the header pressure value of the boiler system 2 significantly exceeding the target pressure value.

In order to control the combustion state of the boiler 20 as described above, the control unit 4 has a configuration shown in FIG. 3A. FIG. 3A is a functional block diagram showing the configuration of the control unit 4.
As shown in FIG. 3A, the control unit 4 includes a steam amount calculation unit 41, a steaming instruction unit 42, a first determination unit 43, an output control unit 44, and a first correction unit 45. Is done.

(Speed type PID control)
The steam amount calculation unit 41 calculates a required steam amount based on a preset target pressure value SV, a steam pressure value PV inside the steam header 6 measured by the steam pressure sensor 7, and the like. Specifically, the steam amount calculation unit 41 sets the necessary steam amount so that the steam pressure value PV inside the steam header 6 measured by the steam pressure sensor 7 becomes a preset target pressure value SV. For example, it is calculated by a speed type PID algorithm.

The steam amount calculation unit 41 calculates the current required steam amount MVn generated from the plurality of boilers 20 based on, for example, the speed type arithmetic expression (1).

MV _n = MV _n-1 + ΔMV _n (1)
Here, when Δt is a control period and n is a positive integer value,
MV _n is the current required steam amount generated from the plurality of boilers 20 in the control cycle n (starting point t0 + n * Δt),
MV _n-1 is the previous required steam amount in the control cycle (n-1),
ΔMV _n represents the required amount of steam change for each control cycle.

The speed type calculation is a method of calculating only the necessary steam amount change ΔMV _{n for} each control cycle and adding the previous required steam amount MV _n−1 to this to calculate the present required steam amount MV _n .
On the other hand, the PID control algorithm that directly calculates the required steam amount MV _n this time for each control cycle is referred to as position calculation.

The required steam amount change ΔMV _{n for} each control cycle is calculated based on the following equations (2) to (7).

ΔMV _n = ΔP _n + ΔI _n + ΔD _n (2)
Here, ΔP _n is the P control output (change).
[Delta] I _n the I control output (change amount),
ΔD _n represents the D control output (change).

_{* ΔP n = K P (e} n -e n-1) ··· (3)
Where K _P is the proportional gain,
e _n have the formula as shown in (4), and the present target pressure value SV _n, the difference (time deviation) between the current steam pressure value PV _n of internal steam header 6 measured by the vapor pressure sensor 7 Represents.

e _n = SV _n −PV _n (4)

_{ΔI n = K P * (Δt} / T I) * e n ··· (5)
T _I represents the integration time.

_{ΔD n = K P * (T} D / Δt) * (e n -2e n-1 + e n-2)
... (6)
Here, _{T D} represents the derivative time.

The steam amount calculation unit 41 calculates a necessary steam amount change ΔMV _n for each control cycle by summing the outputs (changes) calculated by the equations (3), (5), and (6).
The steam amount calculation unit 41 calculates the current required steam amount MV _n by adding ΔMV _n to the previous required steam amount MV _n−1 as shown in Equation (1).
Note that the steam amount calculation unit 41 may apply a PID control algorithm based on position type calculation when calculating the required steam amount.

  When the amount of steam consumed (required load) of the steam using facility 18 increases and reaches the increase reference threshold value, the steaming instruction unit 42 supplies steam to the boiler 20 (increase boiler 20) in the combustion stopped state S0 ( Instruct steaming to start steaming). When there are a plurality of boilers 20 in the combustion stop state S0, a boiler with a higher priority is selected based on the priority. The control unit 4 stores, in the storage unit 5, information indicating that a steaming instruction has been issued with respect to the can boiler 20.

  The first determination unit 43 determines whether the can boiler 20 has started supplying steam (steaming). Here, the determination of the steam supply start can be made based on the steam pressure generated from the booster boiler 20. As an example, when the steam pressure generated from the booster boiler 20 becomes higher than the steam pressure of the steam header 6 by the pressure loss of the steam pipe 11, the first determination unit 43 starts the steam supply. judge. The first determination unit 43 determines that the steam pressure generated from the booster boiler 20 is higher than the steam pressure of the steam header 6 by the pressure loss of the steam pipe 11, and the timer (not shown) detects the burner. You may determine with the increase boiler 20 having started steam supply by measuring that predetermined time passed since ignition.

  Also, such a determination of the start of steaming may be performed not by the control unit 4 of the number control device 3 but by the local control unit 22 of the can boiler 20. When the local control unit 22 determines the start of steaming, the control unit 4 of the number control device 3 determines the start of steaming of the can boiler 20 by receiving a predetermined notification from the local control unit 22. That is, when the local control unit 22 determines that the steam increase boiler 20 has started steaming, the local control unit 22 notifies the unit control device 3 that steaming has started, whereby the control unit 4 (first The determination unit 43) determines whether or not to start the steaming of the booster boiler 20.

  The output control unit 44 controls the combustion state (combustion amount) of the boiler 20 based on the current required steam amount calculated by the steam amount calculating unit 41. The output control unit 44 controls the combustion state of each boiler 20 so that steam corresponding to the necessary steam amount is generated from the boiler group 2.

  The output control unit 44 sets the number of boilers 20 to be burned based on the required steam amount calculated according to the steam consumption amount in the steam amount calculation unit 41. The output control unit 44 sets the boilers 20 that start or stop combustion according to the priority order described in the storage unit 5, and sends a unit control signal (start of operation or operation) to the local control unit 22 of the boilers 20. Stop) is output. Thereby, by controlling the combustion state of each boiler 20 so that steam corresponding to the required steam amount is generated from the boiler group 2, a steam amount corresponding to the required steam amount (hereinafter also referred to as “output steam amount”) is obtained. Supplied to the steam header 6.

  The output control unit 44 continuously sets the combustion rate of the steam supply boiler 20 that is in a combustion state and supplies steam to the steam header 6 according to the required load until the can boiler 20 can be steamed. By changing, the follow-up control of the steam output with respect to the required load is performed. That is, the output control unit 44 instructs the other steam supply boilers 20 capable of outputting steam to output the shortage steam instead until the boiler increaser 20 can steam. So-called backup control is performed to prevent steam shortage. Here, when there are a plurality of steam supply boilers that back up the can boiler 20, the output control unit 44 controls, for example, the combustion rates of the plurality of steam supply boilers to be uniform. Also good.

When it is determined by the first determination unit 43 that the canned boiler 20 can be steamed, the output control unit 44 corresponds to the amount of steam generated from the canned boiler 20 that has started steaming. The can boiler 20 is incorporated in the unit control without reducing the combustion rate of the steam boiler.
In other words, the output control unit 44 determines that the increased boiler 20 is the first determination with respect to the other steam supply boilers 20 that output the insufficient steam instead of the steam increase boiler 20 until it becomes steamable. When it is determined by the unit 43 that steam supply is possible, the increased boiler 20 is incorporated in the unit control while maintaining the combustion amount in which the insufficient steam is output instead. Thereafter, the control unit 4 controls the output steam amount of the can boiler 20 and other steam supply boilers to be a target steam amount according to the required load.

In this case, when the booster boiler 20 can be steamed by the first determination unit 43, the output steam amount may become excessive, but the control unit 4 increases the header pressure value to increase the header. Control is performed so as to reduce the required steam volume so that the pressure value becomes the target pressure value.
As a result, the header pressure value converges to the target pressure value over time.

  By doing so, even if there is a deviation of several seconds in the steaming judgment of the additional boiler 20, the additional boiler 20 is incorporated into the unit control without reducing the combustion rate of the other steam boilers. Therefore, a rapid pressure drop in the boiler system 1 can be prevented.

(First correction unit)
When the header pressure value exceeds the preset first pressure threshold after incorporating the can boiler 20 into the unit control, by correcting the PID parameter in the PI control method or the PID control method, more quickly, The header pressure value can be configured to converge to the target pressure value.

The first correction unit 45 corrects the PID parameter in the PI control method or the PID control method when the header pressure value exceeds a preset first pressure threshold value after the number of boilers 20 has been incorporated into the unit control. Thus, the steam amount calculation unit 41 can calculate an operation amount that is highly responsive to a deviation between the target pressure value and the header pressure value.
By doing so, the header pressure value can be configured to converge to the target pressure value more quickly.

  In order to perform this correction, at least two or more PID parameters are stored in the storage unit 5 in advance.

  Of at least two or more PID parameters, one PID parameter is used as a normal PID parameter. That is, the steam amount calculation unit 41 calculates the required steam amount by the PI control method or the PID control method based on the parameter set by the normal PID parameter among the plurality of PID parameters, and the output control unit 44 calculates the required steam amount. The required amount of steam is supplied to the steam header 6.

  Among at least two or more PID parameters, PID parameters other than normal PID parameters are pre-set as header pressure values after incorporating the can boiler 20 into the unit control as PID parameters at the time of correction. When the first pressure threshold value is exceeded, an operation amount that is highly responsive to the deviation between the target pressure value and the header pressure value is calculated. For this reason, the value set by the PID parameter at the time of correction is set so that the responsiveness is higher than the value set by the PID parameter at the normal time.

  When, for example, a value of 5% is adopted as the value of the proportional band in the PID parameter at the normal time, a value of 3% can be adopted as the value of the proportional band in the PID parameter at the time of correction. Further, when, for example, 30 seconds is adopted as the value of the integration time in the PID parameter at the normal time, a value of 20 seconds, for example, can be adopted as the value of the integration time in the PID parameter at the time of correction.

  By doing so, the steam amount calculation unit 41 calculates the necessary steam amount by the PI control method or the PID control method based on the corrected PID parameter, and the output control unit 44 supplies the necessary steam amount to the steam header. It will be. As a result, it is possible to calculate an operation amount with high responsiveness to the deviation between the target pressure value and the header pressure value, and to quickly converge the header pressure value to the target pressure value.

  The first correction unit 45 performs a correction for calculating an operation amount having high responsiveness to the deviation between the target pressure value and the header pressure value by the PID parameter at the time of correction, and then performs a predetermined time ( For example, after the elapse of 2 to 3 minutes, the first correction unit 45 preferably returns the PID parameter at the time of correction to the PID parameter at the time of normal. Further, when the deviation between the target pressure value and the header pressure value becomes equal to or less than a predetermined value, the control unit 4 may return the PID parameter in the PI control method or the PID control method before replacement.

  By doing so, the steam amount calculation unit 41 again calculates the required steam amount by the PI control method or the PID control method based on the normal PID parameter, and the output control unit 44 uses the required steam amount as a steam header. Will be supplied.

(Control flow of the first embodiment)
Here, with reference to FIG. 5, the outline | summary of the combustion state of the boiler group which concerns on backup control is demonstrated. FIG. 5 is an explanatory diagram showing an example of the combustion state of the boiler group. In FIG. 5, all of the five boilers 20 have the same capacity, and are referred to as a No. 1 boiler, a No. 2 boiler, a No. 3 boiler, a No. 4 boiler, and a No. 5 boiler in order from the left boiler 20.

  When the consumed steam amount (required load) of the steam use facility 18 increases and the required steam amount reaches the increased reference steam amount, the steaming instruction unit 42 instructs steaming to the boiler 20 in the combustion stopped state S0. As shown in FIG. 5, at the time of “(1) Steaming instruction”, the steaming instruction unit 42 is a No. 3 boiler (corresponding to a booster boiler) among the No. 3 boiler to the No. 5 boiler in the combustion stopped state S0. Instructing steaming is given.

When the No. 3 boiler starts combustion based on the steaming instruction, the first determination unit 43 determines whether the No. 3 boiler can supply steam based on the steam pressure of the steam generated from the No. 3 boiler. . As shown in FIG. 5, it is assumed that the “No. 3 boiler” still cannot steam during “(2) Steaming”.
When the steaming instruction for the No. 3 boiler cannot be steamed, the output control unit 44 causes the steam to be generated from the No. 3 boiler to the No. 1 and No. 2 boilers (other steaming boilers) that are already in the combustion state. The combustion rate of the No. 1 boiler and the No. 2 boiler are increased so that they are generated instead of the equivalent to the boiler. Further, the output control unit 44 continuously sets the combustion rates of the No. 1 boiler and the No. 2 boiler in accordance with fluctuations in the amount of steam consumed (required load) of the steam using facility 18 until the No. 3 boiler becomes steamable. Change.

  Thereafter, as shown in FIG. 5, when the “No. 3 boiler starts”, when the No. 3 boiler becomes steamable, steam generated from the No. 1 boiler, No. 2 boiler, and No. 3 boiler is generated from the boiler group 2. Will do. The output control unit 44 incorporates the No. 3 boiler into the unit control without reducing the combustion rate of the No. 1 and No. 2 boilers corresponding to the amount of steam generated from the No. 3 boiler.

When the No. 3 boiler becomes steamable by the first determination unit 43, the output steam amount may become excessive. However, as the header pressure value increases, the control unit 4 determines that the header pressure value is the target. Control is performed to reduce the required amount of steam so that the pressure value is obtained.
As a result, the header pressure value converges to the target pressure value over time. As described above, in the first embodiment, when the No. 3 boiler becomes steamable, the output steam amount may become excessive, but after that, as shown in FIG. After the start of steaming (after a predetermined time has elapsed), the output steam volume is changed to an appropriate steam volume.

In the first embodiment, the first correction unit 45 can be provided. When the header pressure value exceeds a preset first pressure threshold value, the first correction unit 45 corrects the steam amount calculation unit 41 by correcting the PID parameter in the PI control method or the PID control method. With the PID control method based on the PID parameters, it is possible to calculate an operation amount that is highly responsive to the deviation between the target pressure value and the header pressure value.
By doing so, the header pressure value can be configured to converge to the target pressure value more quickly.

(Second embodiment)
Next, a second embodiment of the present invention will be described. The second embodiment will be described mainly with respect to differences from the first embodiment, and detailed description of the same configuration as the first embodiment will be omitted. In the second embodiment, the description of the first embodiment is appropriately applied to points that are not particularly described. Also in the second embodiment, the same effects as in the first embodiment are achieved.

The control unit 4 according to the second embodiment has the configuration shown in FIG. 3B. FIG. 3B is a functional block diagram illustrating a configuration of the control unit 4 according to the second embodiment.
As shown in FIG. 3B, the control unit 4 includes a steam amount calculation unit 41, a steaming instruction unit 42, a first determination unit 43, an output control unit 44, and a second correction unit 46. Is done.

When the difference between the steam pressure value inside the steam header 6 and the target pressure value exceeds a preset second threshold value after the second correcting unit 46 incorporates the can boiler 20 into the unit control, the target pressure value Is corrected to the steam pressure value inside the steam header 6 and then the target pressure value is set so that the target pressure value before correction (the original target pressure value) is gradually restored over a transition time. Correct the information.
By doing so, when the header pressure changes higher than the target pressure, the pressure stability can be converged more quickly and the pressure stability can be maintained.

In FIG. 6, after the number of boilers 20 is incorporated in the unit control, the second correction unit is installed at a time T2 when the difference between the steam pressure value inside the steam header 6 and the target pressure value exceeds a preset second threshold value. A state in which the target pressure value is corrected and the second correction unit returns to the original target pressure value P1 over time T3 is shown.
FIG. 7 shows the transition of the header pressure after time T2.
Hereinafter, the operation of the second correction unit 46 will be described with reference to FIGS. 6 and 7.

  As shown in FIG. 6, initially (before time T <b> 1), the control unit 4 according to the boiler system 1 according to the second embodiment performs control so that the header pressure becomes the target pressure value P <b> 1.

After that, at time T1, for example, when the amount of steam consumed (required load) of the steam use facility 18 increases and the required steam amount reaches the increased reference steam amount, the steaming instruction unit 42 causes the boiler 20 in the combustion stop state S0. The combustion of the (multiple boiler) is started, and the number of boilers 20 in the combustion state is increased.
At this time, the control unit 4 instructs the other steam supply boilers 20 that can output steam to output the shortage of steam instead until the boiler can 20 can be steamed. Prevent the steam shortage, so-called backup.
The header pressure is stabilized by continuously changing the combustion rate of the other steam supply boiler 20 that can output steam according to the fluctuation of the steam consumption (required load) of the steam using facility 18.
As shown in FIG. 6, the control unit 4 controls the header pressure to be the target pressure value P <b> 1 while backing up after time T <b> 1. During this time, as shown in FIG. 7, the header pressure changes substantially in agreement with the target pressure value.

  After that, when it is determined by the first determination unit 43 that the boiler can 20 can be steamed, the combustion amount of the other steaming boiler that has output the shortage of steam instead of the steam amount as it is, The additional boiler 20 is incorporated in the unit control.

  As shown in FIG. 7, when the difference between the header pressure and the target pressure P1 exceeds the second threshold value at time T2, the second correction unit 46 sets the target pressure value P1 set in the setting condition. The header pressure value P2 at time T2 (hereinafter also referred to as “header pressure value P2 at the time of increased capacity”) is corrected. By doing so, as shown in FIG. 6, after time T2, the control unit 4 performs control so that the header pressure becomes the target pressure value P2.

After that, by correcting the target pressure value P2 corrected at the timing of the time Ta between the time T2 and the time T3 to the target pressure value P2 ′, after the time Ta, the control unit 4 causes the header pressure to be the target pressure value. Control to be P2 ′.
Thereafter, by correcting the target pressure value P2 ′ to the target pressure value P2 ″ at the timing of the time Tb between the time Ta and the time T3, after the time Tb, the control unit 4 causes the header pressure to be the target pressure value P2. Control to be ″.
After that, by correcting the target pressure value P2 ″ to the target pressure value P2 ″ at the timing of the time Tc between the time Tb and the time T3, after the time Tc, the control unit 4 makes the header pressure the target pressure. Control is performed so that the value P2 ″ ″ is obtained.
After that, by correcting the target pressure value P2 ′ ″ to the original target pressure value P1 at the timing of time T3, the control unit 4 performs control so that the header pressure becomes the original target pressure value P1 after time T3. To do.
By doing so, as shown in FIG. 7, the header pressure value can be converged to the original target pressure value P1 step by step.

That is, when the second correction unit 46 determines that the difference between the header pressure value P2 and the target pressure value P1 set in the setting condition exceeds the second threshold value at time T2, the second correction unit 46 performs the target in the following procedure. The pressure value P is changed. (Note that the division number n is a predetermined number set in advance.)

(1) The initial target pressure value P1 is corrected to the header pressure value P2.
(2) A set value difference value P3 that is a difference between the initial target pressure value P1 and the target pressure value corrected to the header pressure value P2 is calculated.
(3) The unit time ΔT is calculated by dividing the difference between the time T3 when the initial target pressure value P1 is reached and the time T2 when the setting condition is changed by the predetermined division number n.
(4) A unit difference value ΔP is calculated by dividing the set value difference value P3 by a predetermined division number n.
(5) The unit difference value ΔP is added to the target pressure value P corrected every unit time ΔT.
(6) By doing this, the target pressure value P is changed stepwise so that the initial target pressure value P1 is reached at time T3 after the transition time (T3-T2) has elapsed.

  By doing so, the header pressure can be converged over time from the header pressure value P2 at time T2 to the original target pressure value P1 by PI or PID control of the control unit 4.

  In the above procedure, the order of (3) and (4) may be reversed.

Further, instead of the division number n, the unit time ΔT may be set to a predetermined value.
In this case, (3) in the above procedure may be replaced with the following (3 ′).
(3 ′) The transition time (T3−T2 is divided by a predetermined unit time ΔT to calculate the division number n.

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

(1) In the boiler system 1 of the present embodiment, when the steaming instructing unit 42 gives a steaming instruction to the boiler 20 (a booster boiler) in the combustion stopped state S0, the boiler 20 starts combustion. Here, depending on the state of the can boiler 20, since the supply of steam from the boiler 20 is not performed immediately after the start of combustion, until the first determination unit 43 determines that steam supply is possible, the output control unit 44 is The steam output follow-up control with respect to the required load is performed by continuously changing the combustion rate of the steam supply boiler among the plurality of boilers 20 according to the required load until the additional boiler 20 can be supplied with steam. When it is determined by the first determination unit 43 that the increased boiler 20 can be steamed, the combustion rate of the other steamed boilers corresponding to the amount of steam generated from the increased boiler 20 is not reduced. Incorporating the additional boiler 20 into the unit control.
Thereby, when the can boiler 20 becomes steamable by the 1st determination part 43, there exists a possibility that an output steam amount may become excessive and a header pressure value may increase, but the control part 4 is a header pressure value. The header pressure value converges to the target pressure value as time elapses by controlling so as to reduce the required steam amount so that becomes the target pressure value.

  By doing so, it is possible to prevent a rapid pressure drop of the boiler system 1 even when there is a difference of several seconds in the steam determination of the can boiler by the first determination unit 43.

(2) Moreover, in the boiler system 1 of this embodiment, the 1st correction | amendment part 45 is the 1st pressure by which the steam pressure value inside a steam header was preset after incorporating the can boiler 20 into unit control. When the threshold value is exceeded, the PID parameter (proportional band, integration time, or derivative time) in the PI control method or PID control method is corrected.
As a result, it is possible to calculate an operation amount that is highly responsive to the deviation between the target pressure value and the header pressure value, and it is possible to configure the header pressure value to converge to the target pressure value more quickly. .

  (3) The first correction unit 45 returns to the PID parameter in the PI control method or PID control method before replacement after a predetermined time has elapsed. Thereby, stable control based on the original PID parameter can be performed.

(4) Moreover, in the boiler system 1 of this embodiment, the 2nd correction | amendment part 46 is the difference between the steam pressure value inside a steam header, and a target pressure value after incorporating the can boiler 20 into unit control. When the threshold value is exceeded, the target pressure value is corrected to the steam pressure value inside the steam header, and then the setting condition is corrected so that the target pressure value is gradually returned over the transition time. Can do.
Thereby, even if the header pressure is higher than the target pressure, the pressure stability can be more quickly converged to the target pressure value and the pressure stability can be maintained.

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 each embodiment, when the steam amount is controlled by the control unit 4, the required steam amount is calculated by the speed type PID algorithm. However, the required steam amount may be calculated by the position type PID algorithm.

  Moreover, in each embodiment, when controlling the amount of steam in the control unit 4, the PID control is mainly described as a control algorithm, and details of other controls (PI control) are omitted. The steam amount control executed by the control unit 4 is not limited to PID control, but may be PI control or the like.

  In the first embodiment, in order to correct the PID parameter, the first correction unit 45 presets the normal PID parameter and the correction PID parameter and stores them in the storage unit 5. Instead of the PID parameter, the first correction unit 45 may correct the value of the normal PID parameter.

  For example, in this 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 Boiler 3 Number control apparatus 4 Control part 41 Steam volume calculation part 42 Steaming instruction part 43 1st determination part 44 Output control part 45 1st correction | amendment part 46 2nd correction | amendment part

Claims (5)

A plurality of boilers capable of burning by continuously changing the combustion rate;
A steam header in which steam generated by the plurality of boilers gathers;
A control unit that controls a combustion state of the plurality of boilers according to a required load from a load device,
The controller is
A steam amount calculation unit for calculating the required steam amount by the PI control method or the PID control method so as to keep the steam pressure value inside the steam header at the target pressure value with respect to the fluctuation of the steam consumption amount;
An output control unit for controlling a combustion state of a steam supply boiler that supplies steam among a plurality of boilers so as to generate the necessary steam amount calculated by the steam amount calculation unit;
Depending on the required load, a steaming instruction unit for instructing steaming to start steaming for a boiler that is not steamed among the plurality of boilers,
A first determination unit for determining whether the boiler instructed to steam by the steaming instruction unit has become a steaming boiler;
With
The output controller is requested by continuously changing the combustion rate of the steam supply boiler among the plurality of boilers according to the required load until the steaming-instructed boiler becomes a steam supply boiler. When the steam output follow-up control with respect to the load is performed and it is determined by the first determination unit that the steaming instruction is a steaming boiler, the amount of steam generated from the steaming boiler that has started steaming A boiler system that incorporates the steam supply boiler into the control without reducing the combustion rate of the other steam supply boiler. The controller is
2. The boiler according to claim 1, further comprising a first correction unit configured to correct a PID parameter in the PI control method or the PID control method when a steam pressure value inside the steam header exceeds a preset first pressure threshold value. system.   The boiler system according to claim 2, wherein the first correction unit returns the PID parameter in the PI control method or the PID control method before replacement after a predetermined time has elapsed.   The boiler system according to claim 2, wherein the PID parameter includes a proportional band, an integration time, or a derivative time. The controller is
When the difference between the steam pressure value inside the steam header and the target pressure value exceeds a second threshold, the target pressure value is corrected to the steam pressure value inside the steam header, and then the transition time is set. The boiler system according to claim 1, further comprising a second correction unit that returns the target pressure value step by step.

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