JP5803703B2 - Boiler system - Google Patents

Description

  The present invention relates to a boiler system provided with a unit control means for controlling the combustion amount of a boiler to be controlled so that the steam pressure inside the steam collecting portion falls within a set pressure range.

  Boiler group consisting of multiple boilers that supply steam to load equipment, a steam collecting part (steam header) that collects steam generated in the boiler group, and a steam pressure that measures the steam pressure inside the steam collecting part Set the set pressure range and control boiler total evaporation amount to generate steam with the target evaporation amount according to the required load from the measuring means and the load equipment, and based on the vapor pressure measured by the vapor pressure measuring means There is known a boiler system including a number control means for controlling the combustion amount of a boiler to be controlled so that the vapor pressure falls within a set pressure range.

  In such a boiler system, when the setting conditions such as the set pressure range (upper limit threshold and lower limit threshold) and the total evaporation amount of the control boiler (the setting pattern in the case of unit control is also applicable) are changed, the steam inside the steam header is changed. Even if the pressure does not fluctuate, the combustion amount (necessary combustion amount) of each boiler calculated based on the steam pressure may be changed. In that case, the number of boiler combustions increases or decreases, or the combustion state is changed.

  Further, there may be a large difference between the required combustion amount before the change and the required combustion amount after the change, and the steam pressure inside the steam header may increase or decrease rapidly. For example, if the upper limit threshold of the set pressure range after the change is set low, the steam pressure inside the steam header becomes higher than the upper limit threshold of the set pressure range after the change, and the steam pressure inside the steam header is within the set pressure range. There is a possibility that combustion of all boilers stops (all cans stop) when the upper limit threshold is exceeded.

  In addition, if the number of boiler combustion units is set to a low value when changing the setting conditions, the set pressure range is reconstructed based on the number of combustion units after the change. In some cases, the steam pressure may drop rapidly, and the steam pressure inside the steam header may fall below the lower limit threshold of the set pressure range or hunting may occur.

  In response to such a problem, the applicant of the present invention gradually increases the target combustion amount in the combustion control toward the required combustion amount after the change when the required combustion amount significantly decreases before and after the change of the setting condition. (2) A boiler system to be transferred is proposed (see Patent Document 1 below). According to this boiler system, for example, even if the upper limit threshold of the set pressure range is greatly reduced by changing the setting conditions and the steam pressure inside the steam header exceeds the upper limit threshold of the set pressure range, all boilers Combustion does not stop, but the boiler in the combustion state is reduced by half every predetermined time, and the control can be smoothly shifted to the set condition after the change.

JP 2010-223485 A

  However, the technology related to the control described in Patent Document 1 assumes a case where the required evaporation amount is significantly reduced by changing the setting conditions (for example, when the amount is reduced to less than 50%). Effective when the amount of evaporation has increased significantly, or when the required amount of evaporation after the change has decreased slightly compared to the amount of required combustion before the change (for example, when it has decreased to 50% or more and less than 100%) is not. Therefore, in the technology related to the control described in Patent Document 1, in the case of an unexpected change in setting conditions, there is a possibility that a plurality of boilers may be activated or stopped simultaneously to cause hunting. In addition, the technology related to the control described in Patent Document 1 is mainly intended to suppress an excessive decrease in the steam pressure inside the steam header when the required evaporation amount is significantly reduced when the setting condition is changed. Therefore, the effect of suppressing hunting is low.

  The present invention relates to a boiler system including a unit control means for controlling the combustion amount of a boiler to be controlled so that the steam pressure inside the steam collecting portion falls within the set pressure range. An object of the present invention is to provide a boiler system that can further improve the effect of suppressing hunting when the setting conditions are changed.

  The present invention comprises a plurality of boilers, a boiler group for supplying steam to load equipment, a steam collecting part for collecting steam generated in the boiler group, and a vapor pressure inside the steam collecting part. In order to generate steam with a target evaporation amount corresponding to the required load from the vapor pressure measuring means and the load equipment, the predetermined upper threshold and lower threshold are set as the setting conditions related to the vapor pressure measured by the vapor pressure measuring means. A set pressure range, and a control boiler total evaporation amount that is a total evaporation amount of steam that can be generated by the boiler to be controlled in the boiler group, and the vapor pressure measured by the vapor pressure measuring unit Unit control means for controlling the combustion amount of the boiler to be controlled so that the steam pressure falls within the set pressure range based on the upper limit threshold and the lower limit. When one or more set values X of the threshold value and the total evaporation amount of the control boiler are changed, the set value X to be changed is changed stepwise over a predetermined transition time T1. At this time, the set value difference value Y1 is calculated by subtracting the set value X1 before the change from the set value X2 after the change, and the set value difference value Y1 is divided by the division number n to obtain the unit difference value Y2. For the setting value X to be changed, the unit difference value Y2 is added to the setting value X1 before the change for each unit time T2 that is a time obtained by dividing the transition time T1 by the division number n. In addition, the present invention relates to a boiler system that changes the set value X in a stepwise manner so that the set value X2 is changed after the transition time T1 has elapsed.

  Further, it is preferable to calculate the unit time T2 by dividing the transition time T1 by the division number n before adding the unit difference value Y2 to the set value X1 before the change.

  Further, it is preferable to calculate the division number n by dividing the transition time T1 by the unit time T2 before calculating the unit difference value Y2.

  According to the present invention, in a boiler system including a number control means for controlling the combustion amount of a boiler to be controlled so that the steam pressure inside the steam collecting portion falls within the set pressure range, the set pressure range, the control boiler total evaporation When the setting conditions such as the amount are changed, it is possible to provide a boiler system that can further improve the effect of suppressing hunting.

It is a figure showing the outline of boiler system 1 concerning a 1st embodiment of the present invention. It is a graph which shows the relationship between the combustion pattern and priority before changing the setting conditions of each boiler, and the steam pressure zone of a setting pressure range. It is a graph which shows the relationship between the combustion pattern and priority after changing the setting condition of each boiler, and the steam pressure zone of a setting pressure range. It is a flowchart which shows operation | movement of the boiler system 1 which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the boiler system which concerns on 2nd Embodiment.

[First Embodiment]
Hereinafter, with reference to drawings, boiler system 1 concerning a 1st embodiment of the present invention is explained. FIG. 1 is a diagram showing an outline of a boiler system 1 according to the first embodiment of the present invention.
As shown in FIG. 1, the boiler system 1 of the first embodiment includes a boiler group 2 including a plurality of (four) boilers 20 and a steam header 6 as a steam collecting unit that collects steam generated in the boiler 20. A vapor pressure sensor 7 as a vapor pressure measuring means, a number control device 3 as a number control means, and a setting device 15.
The boiler group 2 produces | generates the vapor | steam supplied to the steam use installation 18 as a load apparatus.

  The upstream side of the steam header 6 is connected to the boiler group 2 (each boiler 20) 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 to adjust the pressure difference and pressure fluctuation between the boilers 20, and supplies the steam whose pressure is adjusted to the steam using equipment 18. It is like that.

  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 boiler system 1 of the present embodiment is capable of supplying the steam generated by the boiler group 2 to the steam use facility 18 operated by steam through 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. At the time of controlling the number of units, the fluctuation of the steam pressure inside the steam header 6 corresponding to this steam consumption is calculated based on the steam pressure (physical quantity) inside the steam header 6 measured by the steam pressure sensor 7. The combustion amount of each boiler 20 constituting the boiler group 2 is controlled.

  If the demand load increases due to an increase in demand for the steam use facility 18 and the amount of steam to be supplied is insufficient, the steam pressure inside the steam header 6 decreases. On the other hand, if the required load decreases due to a decrease in demand for the steam use facility 18 and the amount of supplied steam becomes excessive, the steam pressure inside the steam header 6 increases. For this reason, the fluctuation | variation of a request | requirement load can be monitored with the vapor pressure signal from the vapor pressure sensor 7. FIG. The boiler system 1 is configured to calculate a target evaporation amount corresponding to the consumed steam amount (required load) of the steam using facility 18 based on the steam pressure.

  The setting device 15 is electrically connected to the number control device 3 via the signal line 14. Regarding the combustion control of the boiler group 2, the setting device 15 can change, for example, set conditions (set pressure range, total control boiler evaporation, boiler priority, etc.). Note that setting and changing of the setting conditions by the setting device 15 may be performed entirely or partially manually, or may be performed entirely or partially automatically.

  The boiler 20 is composed of a step value control boiler having a plurality of stepwise combustion positions. A step-value control boiler controls the amount of combustion by selectively turning combustion on / off or adjusting the size of the flame, etc., and gradually increases or decreases the amount of combustion according to the selected combustion position. It is a possible boiler.

  The combustion amount at each combustion position is set so as to generate an amount of steam corresponding to the difference in steam pressure in the steam header 6 to be controlled. In the four boilers 20 composed of the step value control boilers, the combustion amount and the combustion capacity (combustion amount in the high combustion state) at each combustion position may be set equal or different from each other. May be.

The boiler 20 in this embodiment is
1) Combustion stop state (combustion stop position: 0%)
2) Low combustion state (low combustion position: 50%)
3) High combustion state (high combustion position: 100%)
The so-called three-position control is made possible to control the three-stage combustion state (combustion position, load factor). In this case, assuming that the combustion amount in the high combustion state is 1.0, the combustion amount of each boiler 20 can be changed in 0.5 increments.

  Note that the N position control means that the combustion amount of the step value control boiler can be controlled step by step to the N position including the combustion stop state. The number of combustion positions may be 2 positions (that is, only on / off), 4 positions (combustion stop position, low combustion position, middle combustion position, and high combustion position), or 5 positions or more.

  The boiler group 2 has a combustion pattern composed of combinations of the boilers 20 and their combustion positions. In the boiler group 2, each boiler 20 is burned based on this combustion pattern. The combustion pattern may be stored in advance in the form of a table or the like in the storage unit 5 (described later), or may be calculated and calculated by the control unit 4 (described later) each time combustion is performed. FIG. 2 is a graph showing the relationship between the combustion pattern and priority before changing the setting conditions of each boiler, and the vapor pressure zone of the set pressure range. FIG. 3 is a graph showing the relationship between the combustion pattern and priority after changing the setting conditions of each boiler and the vapor pressure zone of the set pressure range.

  In the present embodiment, as shown in FIG. 2, the combustion pattern is “H” when the boiler is in a high combustion state, “L” when the boiler is in a low combustion state, and “−” when the combustion is in a combustion stop state. ". As the combustion pattern, a pattern having a smaller combustion amount is selected as the vapor pressure measured by the vapor pressure sensor 7 is higher, and a pattern having a larger combustion amount is selected as the vapor pressure is decreased. As shown in FIG. 2, the set pressure range Kw1 having the upper threshold Ku1 and the lower threshold Kd1 is equally divided into nine steam pressure zones Kr1, and the corresponding combustion pattern for each steam pressure zone Kr1, in other words, A combustion state (combustion position) is set, and a combustion amount is determined depending on which steam pressure zone Kr1 corresponds to the steam pressure. Nine combustion patterns are set corresponding to the nine vapor pressure zones Kr1.

Priorities are set for the plurality of boilers 20, respectively. The priority order is used to select a boiler 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 “4” are assigned to the first to fourth units of the boiler 20, the first unit has the highest priority and the fourth unit has the highest priority. Lowest.
Of the nine steam pressure zones, all boilers 20 are in the combustion stop state “−” in the highest steam pressure zone, and all boilers 20 are in the high combustion state “H” in the lowest steam pressure zone. It is. From the highest steam pressure zone to the lowest steam pressure zone, the combustion state is changed from “1” to “4” in the order of “−” → “L” → “H”.

  In the present embodiment, after the boiler having the higher priority is changed from the low combustion state “L” to the high combustion state “H”, the next highest boiler is changed from the combustion stop state “−” to the low combustion state “L”. Is changed. After the boiler with the highest priority is changed from the combustion stop state “−” to the low combustion state “L” and before it is changed to the high combustion state “H”, the boiler with the next highest priority is stopped. The state “−” may be changed to the low combustion state “L”.

  In the boiler system 1, only a part of the plurality of boilers 20 can be controlled. For example, as shown in FIG. 3, the operation of the No. 4 machine may be stopped due to a decrease in required load, and only three (No. 1 to No. 3) boilers 20 may be in operation. In this case, the number of vapor pressure zones Kr2 is seven.

  The boiler 20 includes a boiler main body 21 in which combustion is performed, a local control unit 25 that controls the combustion position (combustion state) of each boiler 20, and a local vapor pressure measurement unit 27 that measures the vapor pressure inside each boiler 20. Have.

  The local control unit 25 can control each boiler 20 and change the combustion position (combustion state) according to the required load. The local control unit 25 controls each boiler 20 based on the number control signal from the number control device 3 during the number control, and directly controls the boiler 20 during the local control.

  For example, the local vapor pressure measurement unit 27 includes a vapor pressure sensor and a vapor pressure switch or only a vapor pressure switch, and measures the vapor pressure inside each boiler 20. The local vapor pressure measurement unit 27 measures the vapor pressure used when performing local control of each boiler 20.

  Each boiler 20 is electrically connected to the number control device 3 via the signal line 16. The local control unit 25 transmits a signal used in the number control device 3 during the number control to the number control device 3 via the signal line 16. Examples of the signal used in the number control device 3 include a signal such as a load required for the boiler 20, an actual combustion state of the boiler 20, and other data. In addition, when the controlled boiler 20 is operable, the local control unit 25 transmits a signal indicating that it can be operated (operable signal) to the number control device 3 via the signal line 16.

  When the number control is performed, the number control device 3 shifts the combustion position to the lower side (to the combustion stop position) when the steam pressure inside the steam header 6 measured by the steam pressure sensor 7 becomes higher. The combustion of each boiler 20 is reduced so that the amount of evaporation is reduced, while when the vapor pressure inside the steam header 6 decreases, the combustion position is shifted to the higher side to increase the amount of evaporation. Control the position.

  When local control is performed, the local control unit 25 shifts the combustion position to the lower side (combustion stop position) when the vapor pressure inside the boiler 20 measured by the local vapor pressure measurement unit 27 increases. The combustion of each boiler 20 is reduced so that the amount of evaporation is reduced, while when the vapor pressure inside the boiler 20 becomes low, the combustion position is shifted to the higher side to increase the amount of evaporation. Control the position.

  The number control device 3 is electrically connected to each boiler 20 via a signal line 16. The number control device 3 outputs a combustion instruction signal and controls the number of boilers 20. In addition, when local control is performed on each boiler 20, the number control by the number control device 3 is not performed.

The number control device 3 receives a vapor pressure signal from the vapor pressure sensor 7 via the signal line 13. The number control device 3 calculates the combustion state of each boiler 20 corresponding to the required combustion amount of the boiler group 2 corresponding to the required load and the required combustion amount based on the steam pressure signal from the steam pressure sensor 7, and each boiler. The number control signal is transmitted to 20 local control units 25.
Thus, the number control device 3 controls the amount of combustion of each boiler 20 and controls the number of boiler groups 2.

  The unit control device 3 uses a predetermined upper limit threshold Ku and a set condition relating to the vapor pressure measured by the vapor pressure sensor 7 in order to generate a vapor having a target evaporation amount corresponding to the required load from the vapor use facility 18. A set pressure range Kw having a lower limit threshold Kd and a control boiler total evaporation amount Q are set. Then, the number control device 3 controls the combustion amount of the boiler 20 to be controlled based on the vapor pressure measured by the vapor pressure sensor 7 so that the vapor pressure falls within the set pressure range Kw (select the combustion pattern). To do).

  When the combustion amount is insufficient due to fluctuations in the required load, the unit control device 3 instructs the boiler 20 to raise the combustion position from the combustion stop position to the low combustion position or from the low combustion position to the high combustion position. . If the combustion amount is excessive due to fluctuations in the required load, an instruction to lower the combustion position from the high combustion position to the low combustion position, from the low combustion position to the combustion stop position, or from the high combustion position to the combustion stop position, To 20.

  The control boiler total evaporation amount Q is the total evaporation amount of steam that can be generated by the controlled boiler 20 in the boiler group 2, and the evaporation amount of the boiler that is not the control target is not included in the control boiler total evaporation amount Q. . When the evaporation amounts of all the boilers 20 are the same, the control boiler total evaporation amount Q is proportional to the number of boilers 20 to be controlled. The boiler 20 to be controlled here may be a virtual boiler (described later).

  The combustion of the boiler 20 or its stop can be handled in units of virtual boilers. A virtual boiler is a two-position boiler (combustion stopped state and one combustion state) that generates a combustion amount obtained by subtracting the combustion amount at one combustion position below the combustion amount at one combustion position in a boiler group or one boiler. It is equivalent to the boiler which can generate | occur | produce the combustion amount of one step by ON-OFF control comprised from these.

  For example, when a three-position boiler controlled by a virtual boiler in a combustion stopped state, a low combustion state, and a high combustion state is represented, a first virtual boiler that generates a combustion amount in a low combustion state, and a high combustion from the low combustion state And a second virtual boiler that generates a combustion amount that increases when transitioning to a state (= combustion amount in a high combustion state−combustion amount in a low combustion state), and burns the first virtual boiler When a combustion amount in a low combustion state is generated and the second virtual boiler is burned, the combustion amount in the high combustion state of the three-position boiler is the sum of the combustion amounts of the first virtual boiler and the second virtual boiler. Will occur.

As shown in FIG. 1, the number control device 3 includes a control unit 4 and a storage unit 5.
The control unit 4 is connected to the local control unit 25 of each boiler 20 via the signal line 16. The control unit 4 gives various instructions to the local control unit 25 of each boiler 20 via the signal line 16 and receives various data from the local control unit 25 to the four boilers 20. The above control is performed. When the local control unit 25 of each boiler 20 receives a combustion position change instruction signal from the number control device 3, it controls the boiler 20 according to the instruction. If the actual combustion amount is insufficient with respect to the required combustion amount determined from the load amount of the boiler system having a plurality of boilers, the combustion instruction is given to the boiler 20, and if the actual combustion amount is excessive, The boiler 20 is instructed to stop combustion.

  The storage unit 5 includes instructions given to each boiler 20 under the control of the number control device 3 (the control unit 4), information such as the combustion state (combustion position) received from each boiler 20, and between each boiler 20. The priority order setting information for each boiler 20 is stored.

  When the number of setting values X of the upper limit threshold Ku, the lower limit threshold Kd and the control boiler total evaporation amount Q is changed, the number control device 3 changes over a predetermined transition time T1. The set value X to be changed is changed step by step. Regarding the signs of the set value X (upper limit Ku, lower limit threshold Kd and total control boiler evaporation Q), set pressure range Kw, steam pressure zone Kr, etc., the subscript “1” is attached to those before the change. Subsequent “2” is added to the latter, and no subscript is added when common explanations are made before and after the change.

As shown in FIG. 2, it is assumed that four (No. 1 to No. 4) three-position control boilers 20 are operating under the setting conditions before the change. The number of vapor pressure zones Kr1 is nine.
In addition, as shown in FIG. 3, in the setting conditions after the change, the operation of Unit 4 is stopped due to a reduction in the required load compared to before the change, and the three-position control of three units (Units 1 to 3) It is assumed that the boiler 20 is operating. The number of vapor pressure zones Kr2 is seven.

The number control device 3 changes the setting condition based on the following calculation.
(1) The setting value difference value Y1 is calculated by subtracting the setting value X1 before the change from the setting value X2 after the change.
(2) The unit time T2 is calculated by dividing the transition time T1 by the predetermined division number n.
(3) The unit difference value Y2 is calculated by dividing the set value difference value Y1 by the division number n.
(4) For the set value X to be changed, the unit difference value Y2 is added to the set value X1 before the change every unit time T2.
(5) The set value X is changed step by step so that the changed set value X2 is obtained after the transition time T1 has elapsed.

Next, a specific calculation example will be described. The setting conditions before and after the change are as follows.
[1] Setting condition before change (set value X1)
Upper threshold Ku1 = 0.85 MPa
Lower threshold Kd1 = 0.65 MPa
Control boiler total evaporation Q1 = 10000kg / h
[2] Setting condition after change (set value X2)
Upper threshold Ku2 = 0.80 MPa
Lower threshold Kd2 = 0.64 MPa
Control boiler total evaporation Q2 = 7000kg / h

(1) The setting value X1 before change is subtracted from the setting value X2 after change, and the setting value difference value Y1 (ΔKu1, ΔKd1, ΔQ1) is calculated as follows. In this example, the set value difference value Y1 is minus (−).
Upper limit threshold Ku2 (0.80 MPa) −Upper threshold Ku1 (0.85 MPa) = Upper threshold setting value difference value ΔKu1 (−0.05 MPa)
Lower limit threshold Kd2 (0.64 MPa) −lower limit threshold Kd1 (0.65 MPa) = lower limit threshold set value difference value ΔKd1 (−0.01 MPa)
Control boiler total evaporation amount Q2 (7000 kg / h) −Control boiler total evaporation amount Q1 (10000 kg / h) = Control boiler total evaporation amount set value difference value ΔQ1 (−3000 kg / h)

(2) The unit time T2 is calculated by dividing the transition time T1 by the predetermined division number n. The transition time T1 is set to 60 seconds. The division number n is set to 60. Transition time T1 (60 seconds) ÷ number of divisions n (60) = unit time T2 (1 second).

(3) The set difference value Y1 (ΔKu1, ΔKd1, ΔQ1) is divided by the division number n to calculate a unit difference value Y2 (ΔKu2, ΔKd2, ΔQ2). In this example, the unit difference value Y2 is minus (−).
Upper limit threshold set value difference value ΔKu1 (−0.05 MPa) ÷ number of divisions n (60) = upper threshold value unit difference value ΔKu2 (≈−0.00083 MPa / second)
Lower limit threshold set value difference value ΔKd1 (−0.01 MPa) ÷ number of divisions n (60) = lower limit threshold unit difference value ΔKd2 (≈−0.00017 MPa / second)
Control boiler total evaporation amount set value difference value ΔQ1 (−3000 kg / h) ÷ unit time T2 (1 second) = control boiler total evaporation amount unit difference value ΔQ2 (−50 kg / h / second)

(4) For the set value X to be changed, the unit difference value Y2 (ΔKu2, ΔKd2, ΔQ2) is added to the set value X1 (Ku1, Kd1, Q1) before the change every unit time T2. The upper limit threshold Ku, the lower limit threshold Kd, and the control boiler total evaporation amount Q when the elapsed time T3 has elapsed are as follows.
Upper limit threshold Ku (T3) = upper limit threshold Ku1 (0.85 MPa) + upper limit threshold unit difference value ΔKu2 (−0.00083 MPa / sec) × elapsed time T3
Lower limit threshold Kd (T3) = lower limit threshold Kd1 = 0.65 MPa + lower limit threshold unit difference value ΔKd2 (−0.00017 MPa / second) × elapsed time T3
Control boiler total evaporation Q (T3) = control boiler total evaporation Q1 (10000 kg / h) + (− 50) × elapsed time T3
In addition, when the number of boilers (including virtual boilers) corresponding to the control boiler total evaporation amount Q is a non-integer (decimal number), the number is raised to an integer, for example.

An example in which the elapsed time T3 is 8 seconds (Calculation Example 1) and an example in which the elapsed time T3 is 53 seconds (Calculation Example 2) are shown below.
(Calculation Example 1) When Elapsed Time T3 = 8 Seconds Upper Threshold Ku (T3 = 8) = 0.85 + (− 0.00083 × 8) = 0.84333 MPa
Lower limit threshold Kd (T3 = 8) = 0.65 + (− 0.00017 × 8) = 0.64867 MPa
Control boiler total evaporation Q (T3 = 8) = 10000 + (− 50 × 8) = 99600 kg / h

(Calculation Example 2) When the elapsed time T3 = 53 seconds Upper limit threshold Ku1 (T3 = 53) = 0.85 + (− 0.00083 × 53) = 0.08058 MPa
Lower limit threshold Kd (T3 = 53) = 0.65 + (− 0.00017 × 53) = 0.64116 MPa
Control boiler total evaporation Q (T3 = 53) = 10000 + (− 50 × 53) = 7350 kg / h

Note that after the transition time T1 has elapsed since the setting condition was changed (after the elapsed time T3 = 60 seconds), the changed setting condition (setting value X2) is as follows.
Upper threshold Ku2 = 0.80 MPa
Lower threshold Kd2 = 0.64 MPa
Control boiler total evaporation Q2 = 7000kg / h

  Next, in the boiler system 1 of the first embodiment, when any one or more set values X of the upper limit threshold Ku, the lower limit threshold Kd, and the control boiler total evaporation amount Q are changed, the set value X is The operation of changing from the set value X1 to the set value X2 will be described with reference to FIG. FIG. 4 is a flowchart showing the operation of the boiler system 1 according to the embodiment.

  As shown in FIG. 4, in step ST1, the number control device 3 subtracts the setting value X1 before the change from the setting value X2 after the change to calculate a setting value difference value Y1.

  In step ST2, the number control device 3 calculates the unit time T2 by dividing the transition time T1 by the predetermined division number n.

  In step ST3, the unit control device 3 calculates the unit difference value Y2 by dividing the set value difference value Y1 by the division number n.

  In step ST4, the unit control device 3 adds the unit difference value Y2 to the setting value X1 before the change for each unit time T2 for the setting value X to be changed.

  In step ST5, after the transition time T1 has elapsed, the set value X becomes the changed set value X2.

According to the boiler system 1 of the first embodiment, for example, the following effects are produced.
In the boiler system 1 of the first embodiment, the unit control device 3 changes any one or more set values X of the upper limit threshold Ku and the lower limit threshold Kd of the set pressure range Kw and the control boiler total evaporation amount Q. In the case of being changed, the set value X to be changed is changed stepwise over a predetermined transition time T1, and at that time, the set value X1 before change is subtracted from the set value X2 after change. A value difference value Y1 is calculated, the transition time T1 is divided by a predetermined division number n to calculate a unit time T2, a set value difference value Y1 is divided by the division number n to calculate a unit difference value Y2, For the setting value X to be changed, the setting value X is added so that the unit difference value Y2 is added to the setting value X1 before the change every unit time T2 and the changed setting value X2 is obtained after the transition time T1 has elapsed. Is changed step by step.

  Therefore, according to the first embodiment, when the setting conditions such as the set pressure range and the total evaporation amount of the control boiler are changed, the amount of change in the required evaporation amount can be suppressed, so that the hunting suppression effect is further improved. can do.

[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.

  A second embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the boiler system according to the second embodiment. The second embodiment is mainly different from the first embodiment in that the division number n is calculated. Therefore, the second embodiment will be described with a focus on calculating the division number n.

  In the boiler system of the second embodiment, when any one or more set values X of the upper limit threshold Ku, the lower limit threshold Kd, and the control boiler total evaporation amount Q are changed, the set value X is changed from the set value X1. The operation for changing to the set value X2 will be described with reference to FIG.

  As shown in FIG. 5, in step ST11, the number control device 3 calculates the set value difference value Y1 by subtracting the set value X1 before the change from the set value X2 after the change.

  In step ST12, the number control device 3 calculates the division number n by dividing the transition time T1 by a predetermined unit time T2.

  In step ST13, the number controller 3 divides the set value difference value Y1 by the division number n to calculate a unit difference value Y2.

  In step ST14, the unit control device 3 adds the unit difference value Y2 to the setting value X1 before the change for each unit time T2 for the setting value X to be changed.

  In step ST15, after the transition time T1 has elapsed, the set value X becomes the changed set value X2.

As mentioned above, although preferred embodiment was described, this invention is not limited to embodiment mentioned above, It can implement with a various form.
For example, in the embodiment, the changed set value X2 is smaller than the changed set value X1. Therefore, the set value difference value Y1 and the unit difference value Y2 are both minus (−). However, the changed set value X2 may be larger than the changed set value X1. In this case, the set value difference value Y1 and the unit difference value Y2 are plus (+).

In the first embodiment, before adding the unit difference value Y2 to the setting value X1 before the change, and after calculating the unit time T2 by dividing the transition time T1 by the predetermined division number n, the setting value difference The unit difference value Y2 is calculated by dividing the value Y1 by the division number n, but is not limited thereto. Before adding the unit difference value Y2 to the setting value X1 before the change, after dividing the setting value difference value Y1 by the division number n to calculate the unit difference value Y2, the transition time T1 is divided by the division number n Then, the unit time T2 may be calculated.
In the embodiment, the upper limit threshold Ku and the lower limit threshold Kd of the set pressure range Kw and the control boiler total evaporation amount Q are all changed, but the present invention is not limited to this. The present invention is applied when any one or more of the set values X is changed.

  The steam collecting unit is not limited to the steam header 6 that stores the collected steam, and may be, for example, a steam collecting pipe that simply collects steam.

1 Boiler system 2 Boiler group 3 Number control device (number control means)
6 Steam header (steam collecting part)
7 Vapor pressure sensor (Vapor pressure measuring means)
18 Steam use facilities (load equipment)
20 boiler

Claims (3)

A group of boilers that supply steam to the load equipment,
A steam collecting part for collecting steam generated in the boiler group;
Vapor pressure measuring means for measuring the vapor pressure inside the vapor collecting section;
A set pressure range having a predetermined upper limit threshold and a lower limit threshold as a set condition related to the vapor pressure measured by the vapor pressure measuring means in order to generate a vapor having a target evaporation amount according to a required load from a load device; A control boiler total evaporation amount that is a total evaporation amount of steam that can be generated by the boiler to be controlled among the boiler group, and the steam pressure based on the steam pressure measured by the steam pressure measuring means Unit control means for controlling the combustion amount of the boiler to be controlled, so that is within the set pressure range,
With
When the set value X of any one of the upper limit threshold, the lower limit threshold, and the total amount of evaporation of the control boiler is changed, the number control means changes over a predetermined transition time T1. The set value X to be changed stepwise,
At that time, the setting value difference value Y1 is calculated by subtracting the setting value X1 before the change from the setting value X2 after the change,
Dividing the set value difference value Y1 by the division number n to calculate a unit difference value Y2,
For the set value X to be changed, the unit difference value Y2 is added to the set value X1 before the change for each unit time T2, which is the time obtained by dividing the transition time T1 by the division number n, and the transition time T1 The boiler system which changes the setting value X stepwise so that it becomes the setting value X2 after the change. The boiler system according to claim 1, wherein the unit time T2 is calculated by dividing the transition time T1 by the division number n before adding the unit difference value Y2 to the set value X1 before the change. The boiler system according to claim 1, wherein the division number n is calculated by dividing the transition time T1 by the unit time T2 before calculating the unit difference value Y2.

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