WO2018074310A1

WO2018074310A1 - Boiler system

Info

Publication number: WO2018074310A1
Application number: PCT/JP2017/036948
Authority: WO
Inventors: 山田　和也
Original assignee: 三浦工業株式会社
Priority date: 2016-10-17
Filing date: 2017-10-12
Publication date: 2018-04-26
Also published as: JP6805709B2; JP2018066486A

Abstract

In the present invention, a control unit (4) controls the number of boilers in a boiler group (2) that includes a plurality of step-value control boilers (20), the control unit (4) including: a first priority change unit (43) that, if combustion instructions have been given to a high position combustion virtual boiler by a combustion control unit (42), changes the priority of the high position combustion virtual boiler to which the combustion instructions have been given so as to be the highest among a high combustion boiler group; and a second priority change unit (44) that, if combustion stoppage instructions have been given to a high position combustion virtual boiler by the combustion control unit (42), changes the priority of the high position combustion virtual boiler to which the combustion stoppage instructions have been given so as to be the lowest among the high position combustion virtual boilers in a base combustion boiler group.

Description

Boiler system

The present invention relates to a boiler system including a boiler group having a plurality of stage value control boilers capable of burning at a plurality of staged combustion positions. This application claims priority based on Japanese Patent Application No. 2016-203645 filed in Japan on October 17, 2016, the contents of which are incorporated herein by reference.

Recently, the trend of so-called high turn-down is increasing to increase the turn-down ratio of the three-position control boiler. Here, the turndown ratio means the maximum combustion amount / minimum combustion amount. Conventionally, the combustion rate at the low combustion position was set to 50%, but recently, the combustion rate at the low combustion position is set to, for example, 25%. Increasing cases.
In a three-position controlled boiler, the longer the turndown ratio, the longer the transition time between low combustion and high combustion, so during the transition from low combustion to high combustion or from high combustion to low combustion, It is known that a transition canceling function is installed so that when a request to return to the combustion position occurs, the original combustion position can be returned in a short time (Patent Document 1). However, during the transition period of the combustion position, the transition cancellation can be performed only once.

JP 2010-266157 A

For this reason, if the required steam amount that becomes the required load frequently fluctuates, the number control device enters a state in which the low combustion instruction and the high combustion instruction are switched with respect to the same boiler. Assuming that the difference steam volume between the steam volume at the high combustion position and the steam volume at the low combustion position is a virtual combustion boiler that virtually assumes the boiler, the unit control device determines the combustion volume according to the combustion priority assigned to each high combustion virtual boiler. In order to determine increase / decrease, it is by giving the combustion instruction | indication and combustion stop instruction | indication with respect to the high level combustion virtual boiler of the same boiler.
Here, if a situation occurs in which the low combustion instruction and the high combustion instruction are frequently switched to the same boiler, the transition can be canceled only once during the transition period of the combustion position. In other words, a state in which the indicated amount of steam required and the output steam amount do not match, such as continuously continuing high combustion or temporarily continuing low combustion in response to a high combustion demand, occurs.

More specifically, when it becomes impossible to cancel the transition, when there is a high combustion instruction in a state where the combustion rate is lowered from the high combustion position (100%) to 50% on the way according to the low combustion instruction, Since the transition cannot be canceled, the boiler once returns the combustion rate to the low combustion position (25%) and then operates to raise the combustion rate to the high combustion position (100%) again. On the other hand, a state in which the low combustion state continues temporarily occurs.
Conversely, when it becomes impossible to cancel the transition, when the low combustion instruction is issued when the combustion rate is increased from the low combustion position (25%) to the intermediate combustion rate 50% according to the high combustion instruction, the transition cancellation is performed. Therefore, the boiler once increases the combustion rate to the high combustion position (100%) and then operates to lower the combustion rate to the low combustion position (25%) again. The state which continues a high combustion state generate | occur | produces.
If this happens, response delay will occur in the unit control, so the header pressure, which is the steam pressure in the steam header, will become unstable, and overshoot due to excessive output or undershoot due to excessive output will occur, eventually resulting in a hunting phenomenon there is a possibility.

In the present invention, when the instruction amount (required amount) of the necessary steam amount due to the fluctuation of the header pressure frequently changes, even when the transition cancellation cannot be performed, the instruction amount of the required steam amount and the output steam amount It aims at providing the boiler system which can maintain the pressure stability in unit control by reducing the time when the state which does not agree | coincides occurs.

The present invention provides a boiler group including a plurality of boilers capable of burning at a plurality of staged combustion positions including a base combustion position and a higher combustion position that is a higher combustion position than the base combustion position, A control unit that controls a combustion state of the boiler group, and the control unit includes a base combustion boiler group including a base combustion boiler that burns at the base combustion position in accordance with an increase in required load. When the combustion position of any of the included base combustion boilers is changed from the base combustion position to the high combustion position, the combustion position of the base combustion boiler that is in the base combustion state first among the base combustion boiler group is the high combustion. The high combustion boiler group consisting of a high combustion boiler that burns at the high combustion position according to a decrease in the required load. When changing the combustion position of the combustion boiler from the high combustion position to the base combustion position, the boiler is configured to change the combustion position of the high combustion boiler that is in the high combustion state first among the high combustion boiler group to the base combustion position. About the system.

Further, the control unit burns at the base combustion position with respect to the combustion priority of the high position combustion virtual boiler in which a difference steam amount between the steam amount at the high combustion position and the steam amount at the base combustion position is virtually assumed in the boiler. Combustion priority of the high position combustion virtual boiler of the base combustion boiler group consisting of the base combustion boiler, and combustion priority of the high position combustion virtual boiler of the high combustion boiler group consisting of the high combustion boiler that burns at the high combustion position The combustion priority of the high position combustion virtual boiler with the lowest priority in the base combustion boiler group is higher than the combustion priority of the high position combustion virtual boiler with the highest priority in the high combustion boiler group. The priority order setting unit is set so as to become the combustion priority order set by the priority order setting unit according to the fluctuation of the required load. Therefore, when the combustion instruction is given to the high position combustion virtual boiler, and the combustion instruction is given to the high position combustion virtual boiler by the combustion control part. A first priority changing unit that changes the priority of the high position combustion virtual boiler to be the highest in the group of high level combustion boilers, and a combustion stop instruction is issued to the high position combustion virtual boiler by the combustion control unit. A second priority change for changing the priority of the high-position combustion virtual boiler for which the combustion stop instruction has been issued to the lowest among the high-position combustion virtual boilers of the base combustion boiler group Part.

The first priority changing unit includes a first queue for managing the high-position combustion virtual boilers included in the high-order combustion boiler group in the order in which the high-position combustion state is first set, and the combustion control Preferably, the unit selects the high-position combustion virtual boiler that has entered the high-position combustion state first among the high-level combustion boiler group managed in the first queue and issues a combustion stop instruction.

The second priority changing unit includes a second queue for managing the high-position combustion virtual boilers included in the base combustion boiler group in the order in which the high-position combustion stop state is first set, and the combustion It is desirable that the control unit selects a high-position combustion virtual boiler that is first in a high-position combustion stop state from the group of base combustion boilers managed in the second queue and issues a combustion instruction.

The boiler is configured to be combustible at three positions of a combustion stop position, a low combustion position, and a high combustion position, the base combustion position corresponds to the low combustion position, and the high combustion position is the high combustion position. It can correspond to.

Further, the boiler is configured to be combustible at four positions of a combustion stop position, a low combustion position, a middle combustion position, and a high combustion position, the base combustion position corresponds to the middle combustion position, and the high combustion position is It can correspond to the high combustion position.

According to the present invention, when the instruction amount (required amount) of the necessary steam amount accompanying the fluctuation of the header pressure frequently fluctuates, even if it becomes impossible to cancel the transition, the instruction amount of the required steam amount and the output steam By reducing the time during which a state that does not match the amount occurs, the pressure stability in the number control can be maintained.

It is a figure showing the outline of the boiler system of this embodiment of the present invention. It is a block diagram which shows the function structure of the control part of the number control apparatus in 1st Embodiment. The schematic diagram of the 1st queue in the 1st embodiment and the 2nd queue is shown. It is a figure which shows the outline of a boiler group in case a boiler group consists of 3 position control boilers. When a boiler group consists of 3 position control boilers, it is a figure which shows an example of the combustion priority of a virtual boiler set by the priority setting part. It is a figure which shows the combustion control condition of a boiler with respect to the case where the load fluctuation | variation in case the boiler group of 1st Embodiment consists of 3 position control boilers generate | occur | produces frequently. It is a figure which shows the combustion control condition of a boiler with respect to the case where the load fluctuation | variation in case the boiler group of 1st Embodiment consists of 3 position control boilers generate | occur | produces frequently.

[First Embodiment]
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 according to the embodiment will be described with reference to FIG.
As shown in FIG. 1, the boiler system 1 includes a boiler group 2 including a plurality of (for example, five) step value control boilers 20, and a steam header 6 that collects steam generated in the plurality of step value control boilers 20. A steam pressure sensor 7 that measures the pressure value inside the steam header 6 (hereinafter also referred to as “header pressure value”), and a unit control device 3 that includes a control unit 4 that controls the combustion state of the boiler group 2. Prepare.
The boiler group 2 generates steam to be supplied to the steam use facility 18 as load equipment.

Each of the plurality of stage value control boilers 20 includes a boiler body 21 in which combustion is performed, and a local control unit 22 that controls the combustion position of the stage value control boiler 20. The boiler body 21 includes a water pipe and a burner, and heats can water supplied from a water source (water supply tank) (not shown) in the water pipe to generate steam.

The local control unit 22 changes the combustion position of the step value control boiler 20. Specifically, the local control unit 22 controls the combustion position of the step value control 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 position of the step value control boiler 20.

The steam header 6 is connected to a plurality of step value control boilers 20 constituting the boiler group 2 via a steam pipe 11. The downstream side of the steam header 6 is connected to the steam use facility 18 via the steam pipe 12.

The steam header 6 collects and stores the steam generated in the boiler group 2. The steam header 6 adjusts the pressure difference and pressure fluctuation of the one or more stage value control boilers 20 to be combusted, and supplies steam whose steam pressure value is fixed to the steam using facility 18.

The vapor pressure sensor 7 is electrically connected to the number control device 3 through the signal line 13. The vapor pressure sensor 7 measures a header pressure value, which is a vapor pressure value of the vapor header 6, and transmits a vapor pressure signal corresponding to the vapor pressure value to the number control device 3 via the signal line 13.

The number control device 3 is electrically connected to a plurality of step value control boilers 20 via signal lines 16. The number control device 3 calculates the required steam amount of the boiler group 2 according to the required load based on the header pressure value measured by the steam pressure sensor 7, and performs step value control based on the calculated required steam amount. The combustion state (combustion position) of the boiler 20 is controlled.

Next, the several step value control boiler 20 which comprises the boiler system 1 is demonstrated.
[Virtual boiler]
In general, combustion of the stage value control boiler 20 or its stop can be handled in units of virtual boilers. The virtual boiler regards the difference in the combustion position (combustion amount) in the boiler (for example, the low combustion position, the middle combustion position, the high combustion position, etc.) as independent boilers, and the combustion amount at each combustion position and its one stage. The difference between the combustion amount at the lower combustion position is virtually assumed in the boiler.

For example, a three-position control boiler in which the combustion position of the stage value control boiler 20 is a combustion stop position (first combustion position), a low combustion position L (second combustion position), and a high combustion position H (third combustion position). In this case, the three-position control boiler is a low-burning virtual boiler in which the amount of steam at the low combustion position L (second combustion position) is assumed to be a boiler, and the difference steam between the amount of steam at the high combustion position H and the amount of steam at the low combustion position L. It can be said that it consists of two virtual boilers of the high-burning virtual boiler which virtualized the quantity to the boiler.
That is, when the three-position control boiler is burned at the low combustion position L, it can be handled for the control that the combustion instruction is given to the low-burning virtual boiler and the combustion stop instruction is given to the high-burning virtual boiler. it can. Further, when the three-position control boiler is burned at the high combustion position H, it can be handled in terms of control if a combustion instruction is given to the low-burning virtual boiler and the high-burning virtual boiler.

Further, the combustion position of the stage value control boiler 20 is a combustion stop position (first combustion position), a low combustion position L (second combustion position), a middle combustion position M (third combustion position), and a high combustion position H (first combustion position). In the case of a four-position control boiler that is four combustion positions), the four-position control boiler is a low-burning virtual boiler in which the amount of steam at the low combustion position L (second combustion position) is virtually assumed to be a boiler, and the amount of steam at the middle combustion position M A medium-burning virtual boiler in which the difference steam amount from the steam amount in the low combustion position L is virtually assumed in the boiler, and a high fuel virtual in which the difference steam amount between the steam amount in the high combustion position H and the steam amount in the middle combustion position M is virtually assumed in the boiler. It can be composed of three virtual boilers of the boiler.
That is, when the 4-position control boiler is burned at the low combustion position L, a combustion instruction is given to the low-burning virtual boiler, and a combustion stop instruction is given to the middle-burning virtual boiler and the high-burning virtual boiler. Can be handled for control. In addition, when the 4-position control boiler is burned at the middle combustion position M, the combustion instruction is given to the low-burning virtual boiler and the middle-burning virtual boiler, and the combustion stop instruction is given to the high-burning virtual boiler. Can be handled for control. Further, when the four-position control boiler is burned at the high combustion position H, it can be handled in terms of control if a combustion instruction is given to the low-burning virtual boiler, the middle-burning virtual boiler, and the high-burning virtual boiler.

Similarly, when the combustion position of the stage value control boiler 20 is the N position (N ≧ 5) (in the case of the N position control boiler having a plurality of medium combustion positions), combustion of the N position control boiler or its stop is performed in units of virtual boilers. Can be handled.

As described above, when selecting a boiler that gives a combustion instruction or a combustion stop instruction and a combustion position for a group of boilers composed of the stage value control boilers 20, it can be set in units of virtual boilers.

[Combustion priority]
Each boiler 20 of the boiler group 2 can be set with a priority order that is the combustion order of the combustion position of each boiler 20. The priority order for the step value control boiler 20 can be set for each combustion position of the step value control boiler 20, that is, for each virtual boiler. Hereinafter, the priority set for each combustion position of the boiler 20, that is, for each virtual boiler is also referred to as “combustion priority”.
The combustion priority can be set, for example, using an integer value so that the priority is higher as the numerical value is smaller. FIG. 4B shows an example of the combustion priority assigned to the virtual boiler. Here, the combustion priority of Unit 1 low-burning virtual boiler to Unit 4 low-burning virtual boiler is 1 to 4 respectively, and the combustion priority of Unit 1 high-burning virtual boiler to Unit 4 high-burning virtual boiler is set respectively. It is set to 5-8. Note that Unit 5 is a spare boiler, and the combustion priority of the low-burning virtual boiler is 9 and the combustion priority of the high-burning virtual boiler is 10.

The number control device 3 (control unit 4) burns in order from the virtual boiler having the highest combustion priority.
In addition, when stopping combustion, priority is given to the boiler which is burning in a high combustion position irrespective of a combustion priority, and combustion in the said high combustion position is stopped. For example, when there is a boiler that burns at the high combustion position and a boiler that burns at the low combustion position, the boiler that burns at the high combustion position is controlled to burn at the low combustion position. In terms of a virtual boiler, the high-burning virtual boiler is stopped.
Further, when there are a plurality of boilers burning at the high combustion position H, the combustion is stopped in order from the high-burning virtual boiler having the lowest combustion priority.
Hereinafter, in the first embodiment, unless otherwise specified, the step value control boiler 20 is a three-position control boiler.

Next, the configuration of the number control device 3 will be described. As shown in FIG. 1, the number control device 3 includes a control unit 4 as a control unit and a storage unit 5.

The control unit 4 controls the stage value control boiler 20 by transmitting various instructions to each boiler 20 via the signal line 16 and receiving various data from each boiler 20. More specifically, the control unit 4 controls the combustion position of each boiler 20 based on the required steam amount calculated based on the header pressure value and the combustion priority order of each boiler 20. When each boiler 20 receives a signal for changing the combustion state from the number control device 3, it controls the combustion amount of the corresponding boiler 20 in accordance with the instruction. The detailed configuration of the control unit 4 will be described later.

The storage unit 5 includes the contents of instructions given to each stage value control boiler 20 under the control of the unit control device 3 (control unit 4), information such as the combustion position received from each stage value control boiler 20, combustion Priority setting information and setting information related to changes in combustion priority are stored.
The storage unit 5 is information on the combustion priority of a plurality of virtual boilers in the boiler group 2 set or changed by a priority setting unit 41, a first priority changing unit 43, and a second priority changing unit 44 described later. Remember.
The storage unit 5 may store a first queue and a second queue, which will be described later.

The configuration of the control unit 4 will be described in detail.
Hereinafter, for simplicity, a boiler that burns at a low combustion position is referred to as a low combustion boiler, and a boiler that burns at a high combustion position is referred to as a high combustion boiler. A set of low combustion boilers is called a low combustion boiler group, and a set of high combustion boilers is called a high combustion boiler group.
In addition, combustion at the combustion stop position is referred to as combustion stop, combustion at the low combustion position is referred to as low combustion, and combustion at the high combustion position is also referred to as high combustion.
Further, more generally, the low combustion position can be referred to as a base combustion position, and the high combustion position can be referred to as a high combustion position. In that case, the boiler that burns at the base combustion position is called the base combustion boiler, the boiler that burns at the high combustion position is called the high combustion boiler, the set of base combustion boilers is the base combustion boiler group, and the set of high combustion boilers is the high combustion boiler group It can be said. Further, the difference steam amount between the steam amount at the high combustion position and the steam amount at the base combustion position is virtually assumed in the boiler and can be referred to as a high combustion virtual boiler.

In the description of the control unit 4, the boiler group 2 is assumed to burn a predetermined low-combustion boiler group in a steady state after the boiler system is activated. And the following process to load fluctuation shall be performed by burning or stopping combustion of the high combustion virtual boiler of the boiler which belongs to a predetermined low combustion boiler group with respect to subsequent load fluctuation.
When there are a plurality of low combustion boilers, the control unit 4 sequentially changes the combustion priority of the high-burning virtual boilers according to FIFO (First In First Out) according to the change in the combustion state of the boilers 20 in the boiler group 2.

Specifically, when a certain boiler changes from low combustion to high combustion, the control unit 4 sets the combustion priority of the high-burning virtual boiler of the boiler to the highest rank in the high-combustion boiler group. Moreover, when a certain boiler changes from high combustion to low combustion, the control part 4 makes the combustion priority of the high combustion virtual boiler of the said boiler the lowest order in the low combustion boiler group. In addition, when a certain boiler changes from a combustion stop to low combustion, the control part 4 makes the combustion priority of the high combustion virtual boiler of the said boiler the lowest order in the low combustion boiler group.
By doing so, when burning the high-burning virtual boiler, the control unit 4 burns the high-burning virtual boiler of the boiler that has become the low burning first in the low-burning boiler group with the highest priority. Conversely, when the combustion of the high-burning virtual boiler is stopped, the control unit 4 burns the high-burning virtual boiler of the boiler that has become the first high combustion among the high-burning boiler group with the highest priority.
That is, in the situation where the low combustion instruction and the high combustion instruction are frequently switched, such as low combustion-> high combustion-> low combustion-> high combustion, the control unit 4 performs the boiler, high combustion, The boilers with low combustion can be sequentially switched cyclically.
By doing so, even in situations where the low combustion instruction and the high combustion instruction are frequently switched, the pressure stability in the unit control is maintained by reducing the state in which the required steam amount does not match the output steam amount. be able to.

In order to implement such control, as shown in FIG. 2, the control unit 4 includes a priority setting unit 41, a combustion control unit 42, a first priority changing unit 43, and a second priority changing unit 44. And comprising.

<Priority order setting unit 41>
The priority setting unit 41 broadly divides the boiler group 2 into a low combustion boiler group and a high combustion boiler group. The combustion priority of the high combustion virtual boiler of the boiler 20 belonging to the low combustion boiler group is assigned, and then the combustion priority of the high combustion virtual boiler of the boiler 20 belonging to the high combustion boiler group is assigned so as to satisfy the following conditions.
conditions:
The combustion priority of the high-burning virtual boiler with the lowest priority in the low-combustion boiler group is higher than the combustion priority of the high-burning virtual boiler with the highest priority in the high-burning boiler group.

In addition, the combustion priority of the high-burning virtual boiler of the boiler 20 belonging to the low-combustion boiler group and the combustion priority of the high-burning virtual boiler having the highest priority in the high-burning boiler group set by the priority setting unit 41. Each rank is stored in the storage unit 5.

Further, the storage unit 5 may be provided with a first queue and a second queue.
The first queue is configured to store and manage the high-burning virtual boilers included in the high-combustion boiler group in the order of the highest combustion state first, and the second queue includes the low-burning boiler group. The high-burning virtual boiler included can be configured to be stored and managed in the order in which the low-burning state is the first.
FIG. 3 shows a schematic diagram of the first queue and the second queue. As shown in FIG. 3, the first queue manages the combustion priority of the high combustion virtual boiler in the high combustion boiler group, and the second queue manages the combustion priority of the high combustion virtual boiler in the low combustion boiler group.
The high-burning virtual boiler that is retired or deleted from the first queue in response to the combustion stop instruction is managed to immediately arrive at the end of the second queue, that is, to be incorporated. Conversely, the high-burning virtual boiler that is retired or deleted from the second queue in response to the combustion instruction is managed to arrive at the end of the first queue, that is, to be incorporated immediately.

<Combustion control unit 42>
The combustion control unit 42 gives a combustion instruction or a combustion stop instruction to the high-burning virtual boiler based on the combustion priority set by the priority setting unit 41 in accordance with a change in the required load.
When storing and managing the combustion priority of the high-burning virtual boiler using the first queue and the second queue, the combustion control unit 42 issues a combustion instruction or a combustion stop instruction to the high-burning virtual boiler as follows. Can do.
When the combustion control unit 42 issues a combustion stop instruction to the high-burning virtual boilers belonging to the high-burning boiler group, the combustion control unit 42 selects the high-burning virtual boiler stored at the head of the first queue and issues a combustion stop instruction.
Moreover, the combustion control part 42 selects the high fuel virtual boiler memorize | stored in the head of the 2nd queue, and performs a combustion command, when giving a combustion command with respect to the high fuel virtual boiler which belongs to the low combustion boiler group.

<First priority changing unit 43>
When the combustion control unit 42 gives a combustion instruction to the high-burning virtual boiler belonging to the low-combustion boiler group, the first priority changing unit 43 increases the priority of the high-burning virtual boiler for which the combustion instruction has been issued. It changes so that it may become the highest in the high combustion virtual boiler of the boiler 20 which belongs to a combustion boiler group.
When storing and managing the combustion priority of the high-burning virtual boiler using the first queue and the second queue, the first priority changing unit 43 may change the priority of the high-burning virtual boiler as follows. it can.
The first priority changing unit 43 deletes the high-burning virtual boiler stored at the head of the second queue from the second queue, and changes the order of the remaining high-burning virtual boilers stored in the second queue. By shifting forward, the second queue can be reconfigured so that the high-burning virtual boilers included in the low-burning boiler group are stored and managed in the order in which they first enter the low-burning state.
The first priority changing unit 43 stores the high-burning virtual boiler in which the combustion instruction is given at the end of the first queue, so that the high-burning virtual boiler included in the high-burning boiler group is the earliest. The first queue can be reconfigured so as to be stored and managed in the order of the high combustion state.

<Second priority changing unit 44>
When the combustion control unit 42 gives a combustion stop instruction to the high-burning virtual boiler, the second priority changing unit 44 sets the priority order of the high-burning virtual boiler to which the combustion stop instruction has been given to the low-burning boiler group. It changes so that it may become the lowest in the high burning virtual boiler of the boiler 20 to which it belongs.
When storing and managing the combustion priority of the high-burning virtual boiler using the first queue and the second queue, the second priority changing unit 44 may change the priority of the high-burning virtual boiler as follows. it can.
The second priority changing unit 44 deletes the high-burning virtual boiler stored at the head of the first queue from the first queue, and changes the order of the remaining high-burning virtual boilers stored in the first queue. By shifting forward, the first queue can be reconfigured so that the high-burning virtual boilers included in the high-burning boiler group are stored and managed in the order in which they first enter the high-burning state.
In addition, the second priority changing unit 44 stores the high-burning virtual boiler instructed to stop combustion at the end of the second queue, so that the high-burning virtual boiler included in the low-burning boiler group is the most. The second queue can be reconfigured to store and manage in the order in which the low combustion state first occurred.

As described above, by managing the combustion priority of the high-burning virtual boiler using the first queue and the second queue, the combustion control unit 42 increases the load and burns to the high-burning virtual boiler. When instructing, it is possible to quickly and easily select the high-burning virtual boiler that is the target of the combustion instruction from the group of low-burning boilers.
In addition, when the load is reduced and the combustion control unit 42 issues a combustion stop instruction to the high combustion virtual boiler, the combustion control unit 42 quickly and easily selects the high combustion virtual boiler that is the target of the combustion stop instruction in the high combustion boiler group. You can choose from.
In addition, the 1st priority change part 43 and the 2nd priority change part 44 change the combustion priority of a high fuel virtual boiler to the last, and do not change the starting priority of a boiler itself.

Next, the operation of the boiler system 1 of the first embodiment will be described. FIGS. 4A, 4B, 5, and 6 are diagrams showing the combustion priority order and the combustion operation of the virtual boiler when the boiler group 2 is composed of a three-position control boiler.

As shown in FIG. 4A, the combustion amount at the low combustion position L of each stage value control boiler 20 is 200 kg / h, and the combustion amount (maximum output steam amount) at the high combustion position H is 800 kg / h.
The combustion amount of the low-burning virtual boiler is 200 kg / h, and the combustion amount of the high-burning virtual boiler is 600 kg / h.
As shown in FIG. 4B, the combustion priority of the virtual boiler is set to 1 to 4 for the combustion priority of the low-burning virtual boiler of unit 1 to 4 for the low-burning virtual boiler of unit 4, respectively. The combustion priority of the high-burning virtual boiler of Unit No. 5 is set to 5-8, respectively. In Unit 5, the combustion priority of the low-burning virtual boiler is 9 and the combustion priority of the high-burning virtual boiler is 10, which is a spare boiler.

Next, referring to FIG. 5, the required amount of steam from the amount of steam that can be provided by four low-burning virtual boilers (800 kg / h) to the amount of steam that can be supplied by four low-burning virtual boilers and one high-burning virtual boiler (1400 kg / hour). The combustion control operation of the high-burning virtual boiler when the increase / decrease is repeated within the range of h) will be described.
In addition, the number described in the virtual boiler represents the combustion priority of the virtual boiler.
First, as shown in FIG. 5A, four low-burning virtual boilers of Units 1 to 4 burn to cover the necessary steam amount.

When the load increases and the required amount of steam exceeds the amount of steam that can be covered by the four low-burning virtual boilers, the combustion control unit 42, as shown in FIG. A combustion instruction is given to a high-burning virtual boiler (No. 1) having a high height.
By doing so, the boiler group 2 is roughly divided into a high-combustion boiler group consisting only of Unit 1 and a low-combustion boiler group consisting of Units 2 to 4. The first priority changing unit 43 sets the priority of the high-burning virtual boiler (unit 1) to the highest combustion priority in the high-combustion boiler group, and belongs to the boilers (from unit 2 to 4). Change to a value lower than any of the combustion priority of the high-burning virtual boiler of Unit No.). Specifically, the first priority changing unit 43 changes the priority of the high-burning virtual boiler of the first unit to 8, and sets the priority of the high-burning virtual boilers of the second to fourth units to 5 to 7, respectively. Change to

Next, when the load decreases and the required amount of steam reaches the amount of steam that can be covered by four low-burning virtual boilers, the combustion control unit 42, as shown in FIG. A combustion stop instruction is given to the high-burning virtual boiler (unit 1) having the lowest priority among the boilers.
By doing so, the high-combustion boiler group becomes an empty set, and the boiler group 2 becomes only the low-combustion boiler group including the first to fourth machines. The second priority changing unit 44 changes the combustion priority of the high-burning virtual boiler (unit 1), for which the combustion stop instruction has been issued, to the lowest value among the high-burning virtual boilers of the low-burning boiler group. . Specifically, since the combustion priority of the high-burning virtual boiler (unit 1) is already the lowest value 8 among the high-burning virtual boilers in the low-burning boiler group, the value is continued as it is.

Next, when the load increases and the required steam amount exceeds the steam amount that can be covered by the four low-burning virtual boilers, as shown in FIG. Among them, a combustion instruction is given to a high-burning virtual boiler (unit 2) having a high combustion priority.
By doing so, the boiler group 2 is divided roughly into the high combustion boiler group which consists only of No. 2, and the low combustion boiler group which consists of No. 1, No. 3, and No. 4. The first priority changing unit 43 sets the priority of the high combustion virtual boiler (No. 2) to the highest combustion priority in the high combustion boiler group, and belongs to the boilers (No. 1, 3 and No. 3). No. 4 and No. 4) are changed so as to be lower than the combustion priority of any of the high-burning virtual boilers. Specifically, the first priority changing unit 43 changes the priority order of the high-burning virtual boiler of the second unit to 8, and sets the priority order of the high-burning virtual boilers of the third, fourth, and first units, Change to 5-7.

Hereinafter, similarly, load reduction and load increase are repeated.
When the load increases and the required steam amount exceeds the steam amount that can be covered by the four low-burning virtual boilers, the combustion control unit 42 gives a combustion instruction to the high-burning virtual boilers with high combustion priority among the high-burning virtual boilers. I do. At that time, the first priority changing unit 43 changes the priority of the high-burning virtual boiler that has instructed the combustion to 8, and changes the priority of the high-burning virtual boilers of other units to 5 to 7, respectively. To do.

As described above, in a situation where the low combustion instruction and the high combustion instruction are frequently switched, such as low combustion-> high combustion-> low combustion-> high combustion, the control unit 4 performs a boiler that changes from low combustion to high combustion. In addition, it is possible to sequentially switch the boiler from low combustion to low combustion cyclically.
By doing so, even in situations where the low combustion instruction and the high combustion instruction are frequently switched, the pressure stability in the unit control is maintained by reducing the state in which the required steam amount does not match the output steam amount. be able to.

Next, referring to FIG. 6, three low-burning virtual boilers and two high-burning virtual boilers from the amount of steam (1400 kg / h) required for the required steam volume by four low-burning virtual boilers and one high-burning virtual boiler. The combustion control operation of the high-burning virtual boiler in the case where the increase / decrease is repeated within the range of the steam amount (2000 kg / h) that can be covered by this will be described.
Like FIG. 5, the number described in the virtual boiler represents the combustion priority of the virtual boiler.
First, in FIG. 6A, four low-burning virtual boilers of Units 1 to 4 burn to cover the necessary steam amount.

When the load increases and the required amount of steam exceeds the amount of steam that can be covered by four low-burning virtual boilers, as shown in FIG. 6 (B), the combustion control unit 42 is a high-burning virtual boiler belonging to the low-burning boiler group. Among them, a combustion instruction is given to a high-burning virtual boiler (unit 1) having a high combustion priority.
By doing so, the boiler group 2 is roughly divided into a high-combustion boiler group consisting only of Unit 1 and a low-combustion boiler group consisting of Units 2 to 4. The first priority changing unit 43 sets the priority of the high-burning virtual boiler (No. 1) as the highest combustion priority in the high-combustion boiler group, and the boilers belonging to the low-burning boiler group (from No. 2 to 4). Change to a value lower than any of the combustion priority of the high-burning virtual boiler of Unit No.). Specifically, the first priority changing unit 43 changes the priority of the high-burning virtual boiler of the first unit to 8, and sets the priority of the high-burning virtual boilers of the second to fourth units to 5 to 7, respectively. Change to

Further, when the load increases and the required steam volume exceeds the steam volume (1400 kg / h) that can be covered by four low-burning virtual boilers and one high-burning virtual boiler, combustion control is performed as shown in FIG. The unit 42 gives a combustion instruction to a high-burning virtual boiler (unit 2) having a high combustion priority among the high-burning virtual boilers belonging to the low-burning boiler group.
By doing so, the boiler group 2 is divided roughly into the high combustion boiler group which consists of the 1st machine and the 2nd machine, and the low combustion boiler group which consists of the 3rd machine and the 4th machine. The first priority changing unit 43 sets the priority of the high-burning virtual boiler (No. 2) to the highest combustion priority in the high-combustion boiler group, and belongs to the low-combustion boiler group (No. 3 and 4). Change to a value lower than any of the combustion priority of the high-burning virtual boiler of Unit No.). Specifically, the first priority changing unit 43 changes the priority of the second high-burning virtual boiler to 7 and changes the priority of the third high-burning virtual boiler to 5. Change the priority of the No. 4 high-burning virtual boiler to 6.

Next, when the load decreases and the required steam amount becomes the steam amount (1400 kg / h) that can be covered by four low-burning virtual boilers and one high-burning virtual boiler, as shown in FIG. The combustion control unit 42 issues a combustion stop instruction to the high-burning virtual boiler (unit 1) having the lowest priority among the high-burning virtual boilers during combustion.
By doing so, the high combustion boiler group becomes only No. 2, and the boiler group 2 becomes only the low combustion boiler group consisting of No. 1, No. 3, and No. 4. The second priority changing unit 44 changes the combustion priority of the high-burning virtual boiler (unit 1) for which the combustion stop instruction has been given to the lowest value 7 among the high-burning virtual boilers of the low-burning boiler group. To do. The second priority changing unit 44 changes the combustion priority of the high combustion virtual boiler (unit 2) of the high combustion boiler group to a value 8 lower than the combustion priority of any high combustion virtual boiler of the low combustion boiler group. To do.

When the load increases and the required steam amount exceeds the steam amount (1400 kg / h) that can be covered by four low-burning virtual boilers and one high-burning virtual boiler, as shown in FIG. Gives a combustion instruction to a high-burning virtual boiler (No. 3) having a high combustion priority among the high-burning virtual boilers of the low-burning boiler group.
By doing so, the boiler group 2 is divided roughly into the high combustion boiler group which consists only of No. 2 and No. 3, and the low combustion boiler group which consists of No. 1 and No. 4. The first priority changing unit 43 sets the priority of the high-burning virtual boiler (No. 3) to the highest combustion priority among the high-combustion boilers, and belongs to the low-combustion boilers (Nos. 1 and 4). Change to a value lower than any of the combustion priority of the high-burning virtual boiler of Unit No.). Specifically, the first priority changing unit 43 changes the priority order of the No. 3 high-burning virtual boiler to 7, and changes the priority order of the No. 4 high-burning virtual boiler to 5. Change the priority of the first high-burning virtual boiler to 6.

Next, when the load decreases and the required steam amount becomes the amount of steam (1400 kg / h) that can be covered by four low-burning virtual boilers and one high-burning virtual boiler, as shown in FIG. The combustion control unit 42 issues a combustion stop instruction to the high-burning virtual boiler (unit 2) having the lowest priority among the high-burning virtual boilers that are burning.
By doing so, the boiler group 2 is divided roughly into the high combustion boiler group which consists only of No. 3, and the low combustion boiler group which consists of No. 1, No. 2, and No. 4. The second priority changing unit 44 changes the combustion priority of the high-burning virtual boiler (No. 2) for which the combustion stop instruction has been given to the lowest value 7 among the high-burning virtual boilers of the low-burning boiler group. To do. Further, the second priority changing unit 44 changes the combustion priority of the high combustion virtual boiler (No. 3) of the high combustion boiler group to a value 8 lower than the combustion priority of any high combustion virtual boiler of the low combustion boiler group. To do.

Next, when the load increases and the required steam volume exceeds the steam volume (1400 kg / h) that can be covered by 4 low-burning virtual boilers and 1 high-burning virtual boiler, as shown in FIG. The control unit 42 gives a combustion instruction to a high-burning virtual boiler (No. 4) having a high combustion priority among the high-burning virtual boilers of the low-burning boiler group.
By doing so, the boiler group 2 is divided roughly into the high combustion boiler group which consists of the 3rd machine and the 4th machine, and the low combustion boiler group which consists of the 1st machine and the 2nd machine. The first priority changing unit 43 sets the priority of the high-burning virtual boiler (No. 4) as the highest combustion priority in the high-combustion boiler group, and belongs to the low-combustion boiler group (No. 1 and 2). Change to a value lower than any of the combustion priority of the high-burning virtual boiler of Unit No.). Specifically, the first priority changing unit 43 changes the priority of the No. 4 high-burning virtual boiler to 7, and changes the priority of the No. 1 high-burning virtual boiler to 5. Change the priority of the high-burning virtual boiler of Unit 2 to 6.

As described above, in the situation where the low combustion instruction and the high combustion instruction are frequently switched, such as low combustion-> high combustion-> high combustion-> low combustion-> high combustion, the control unit 4 performs the operation from low combustion to high combustion. The boiler which becomes combustion and the boiler which becomes low combustion from high combustion can be switched cyclically.
By doing so, even in situations where the low combustion instruction and the high combustion instruction are frequently switched, the pressure stability in the unit control is maintained by reducing the state in which the required steam amount does not match the output steam amount. be able to.

[effect]
In the boiler system 1 according to the first embodiment, when the combustion control unit 42 gives a combustion instruction to a high-burning virtual boiler belonging to the low-combustion boiler group, the first priority changing unit 43 receives the combustion instruction. The priority of the performed high-burning virtual boiler is changed to be the highest among the high-burning virtual boilers of the boilers 20 belonging to the high-burning boiler group. Further, when a combustion stop instruction is issued to the high-burning virtual boiler by the combustion control unit 42, the priority order of the high-burning virtual boiler for which the combustion stop instruction is given by the second priority changing unit 44 is set to the low-burning boiler. It changes so that it may become the lowest in the high burning virtual boiler of the boiler 20 which belongs to a group.
By doing so, for example, in response to the high turndown of the three-position control boiler, a request to return to the original combustion position frequently occurred during the transition from low combustion to high combustion or from high combustion to low combustion. Even in this case, by switching the boiler that changes the combustion amount cyclically, it becomes possible to reduce the discrepancy between the required amount at the time of transition and the steam output amount and maintain the pressure stability in the unit control. .

In the boiler system 1 according to the first embodiment, the first queue is used to store and manage the high-burning virtual boilers included in the high-combustion boiler group in the order of the highest combustion state first, and the second queue. Thus, the high-burning virtual boilers included in the low-burning boiler group are stored and managed in the order in which the combustion is stopped first.
By doing so, the combustion control unit 42 selects the high-burning virtual boiler stored at the head of the first queue when issuing a combustion stop instruction to the high-burning virtual boilers belonging to the high-burning boiler group. When a combustion stop instruction is issued and a combustion instruction is issued to a high-burning virtual boiler belonging to the low-burning boiler group, the high-burning virtual boiler stored at the head of the second queue can be selected and the burning instruction can be issued. . For this reason, the combustion control unit 42 can quickly and easily select the high-burning virtual boiler that is the target of the combustion instruction or the combustion stop instruction.

[Modification 1]
As described above, in the first embodiment, the step value control boiler 20 is a three-position control boiler, but is not limited to a three-position control boiler. For example, it can be applied to a four-position control boiler.
In particular, it is effective when the ratio between the maximum combustion amount and the medium combustion amount of the four-position control boiler is large, and the same effect as the case of the three-position control boiler is achieved.

In the case of a three-position control boiler, the low combustion position was the base combustion position, and the high combustion position was the high combustion position. On the other hand, in the case of a four-position control boiler, the middle combustion position can be the base combustion position and the high combustion position can be the high combustion position.
Hereinafter, the boiler that burns at the medium combustion position is referred to as a medium combustion boiler, and the boiler that burns at the high combustion position is referred to as a high combustion boiler. A set of medium combustion boilers is called a medium combustion boiler group, and a set of high combustion boilers is called a high combustion boiler group.
In the boiler group 2, it is assumed that a predetermined medium combustion boiler group burns in a steady state after the boiler system is started. And the following process to load fluctuation shall be performed by burning or stopping combustion of the high combustion virtual boiler of the boiler which belongs to a predetermined middle combustion boiler group with respect to subsequent load fluctuation.
Even in the case of the four-position control boiler, the control unit 4 sets the combustion priority of the high-burning virtual boiler to FIFO (in accordance with the change in the combustion state of the boilers 20 of the boiler group 2 when there are a plurality of medium combustion boilers. First In First Out).

In the case of the four-position control boiler 20, the four-position control boiler 20 is changed to the base combustion position instead of the low-combustion position in the three-position control boiler 20, and the four-position control boiler 20 is changed to the high-burning position in the four-position control boiler 20. This can be explained by replacing the high combustion position of the control boiler 20 as the high combustion position.

[Modification 2]
Similarly, it goes without saying that the present invention can also be applied when the step value control boiler 20 is an N position control boiler (N ≧ 5) (in the case of an N position control boiler having a plurality of medium combustion positions). The present invention can also be applied to an arbitrary N position control boiler by setting the (N-1) combustion position as a base combustion position and the N position as a high combustion position, for example.

[Modification 3]
In the present embodiment, the boiler group 2 includes the five step value control boilers 20, but is not limited thereto. The number of stage value control boilers 20 can be set as appropriate.

[Modification 4]
In the present embodiment, the boiler capacity of the three-position control boiler 20 included in the boiler group 2 and the combustion rate at each combustion position are the same, but may be different for each three-position control boiler 20.
[Modification 5]
In this embodiment, although the five step value control boilers 20 are three-position control boilers, the present invention is not limited to this. That is, the boiler capacity of each stage value control boiler 20 included in the boiler group of the present invention, the number of stages at the combustion position, the combustion rate at each combustion position, and the like may be different for each stage value control boiler 20. .

DESCRIPTION OF SYMBOLS 1 Boiler system 2 Boiler group 20 Stage value control boiler 3 Number control apparatus 4 Control part 41 Priority order setting part 42 Combustion control part 43 1st priority order change part 44 2nd priority order change part 5 Storage part

Claims

A boiler group including a plurality of boilers capable of burning at a plurality of staged combustion positions including a base combustion position and a higher combustion position that is a higher combustion position than the base combustion position;
A control unit for controlling the combustion state of the boiler group according to a required load;
A boiler system comprising:
The controller is
When changing the combustion position of any of the base combustion boilers included in the base combustion boiler group consisting of the base combustion boilers that burn at the base combustion position from the base combustion position to the higher combustion position in accordance with an increase in the required load, In the base combustion boiler group, the combustion position of the base combustion boiler that is in the base combustion state first is changed to the high combustion position,
When changing the combustion position of any high combustion boiler included in the high combustion boiler group consisting of high combustion boilers combusting at the high combustion position from the high combustion position to the base combustion position according to a decrease in the required load, A boiler system that changes the combustion position of a high-level combustion boiler that is in a high-level combustion state first in a group of high-level combustion boilers to a base combustion position.
The controller is
Base combustion consisting of a base combustion boiler that burns at the base combustion position with respect to the combustion priority of the high position combustion virtual boiler assuming a difference steam amount between the steam amount at the high combustion position and the steam amount at the base combustion position in a boiler Combustion priority of the high position combustion virtual boiler of the boiler group and combustion priority of the high position combustion virtual boiler of the high combustion boiler group consisting of a high combustion boiler that burns at the high combustion position, the base combustion boiler group Priority is set so that the combustion priority of the high-position combustion virtual boiler with the lowest priority among the high priority combustion virtual boilers is higher than the combustion priority of the high-position combustion virtual boiler with the highest priority among the high-order combustion boiler group A rank setting section;
A combustion control unit that gives a combustion instruction or a combustion stop instruction to the high-position combustion virtual boiler based on a combustion priority set by the priority setting unit according to a change in a required load;
When a combustion instruction is given to the high position combustion virtual boiler by the combustion control unit, the priority of the high position combustion virtual boiler for which the combustion instruction has been given becomes highest among the high order combustion boiler group When the combustion stop instruction is given to the high-position combustion virtual boiler by the first priority changing section and the combustion control section, the priority order of the high-position combustion virtual boiler for which the combustion stop instruction has been issued is The boiler system according to claim 1, further comprising: a second priority changing unit that changes the lowest value among the high-position combustion virtual boilers of the base combustion boiler group.
The first priority changing unit
Comprising a first queue for managing the high-position combustion virtual boilers included in the high-order combustion boiler group in the order in which the high-position combustion state is first set;
The combustion control unit
The boiler system according to claim 2, wherein a combustion stop instruction is issued by selecting the high-position combustion virtual boiler that is first in the high-position combustion state from among the high-order combustion boiler group managed in the first queue. .
The second priority changing unit
A second queue for managing the high-position combustion virtual boilers included in the base combustion boiler group in the order in which the high-position combustion stop state was first set;
The combustion control unit
The combustion instruction is performed by selecting a high-position combustion virtual boiler that has been in a high-position combustion stop state first among the base combustion boiler group managed in the second queue. The described boiler system.
The boiler is configured to be combustible at three positions of a combustion stop position, a low combustion position, and a high combustion position,
The base combustion position corresponds to the low combustion position;
The boiler system according to any one of claims 1 to 4, wherein the high combustion position corresponds to the high combustion position.
The boiler is configured to be combustible at four positions of a combustion stop position, a low combustion position, a middle combustion position, and a high combustion position,
The base combustion position corresponds to the middle combustion position;
The boiler system according to any one of claims 1 to 4, wherein the high combustion position corresponds to the high combustion position.