JP2013204907A - Boiler system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boiler system capable of improving responsiveness with respect to a variation in a load to be required.SOLUTION: A boiler system 1 includes a boiler group 2 having a plurality of boilers 20, and a control part controlling the boiler group 2. When receiving an instruction for stopping the boilers 20 at a predetermined frequency, the control part shifts the boilers 20 which has received the instruction for stopping received in a steam supply preparation state. Also, the boilers 20 are boilers 20 capable of performing combustion in a combustion state at a plurality of positions including a first combustion position (L) and a second combustion position (H), and the control part preferably outputs the instruction for stopping to the boilers 20 positioned in the first combustion position (L).

Description

  The present invention relates to a boiler system including a boiler group composed of a plurality of boilers.

  Conventionally, in a boiler system including a boiler group composed of a plurality of boilers and a control unit that controls the boiler group, the boiler group when a required load fluctuates by setting a combustion pattern of the plurality of boilers Is controlled (see, for example, Patent Document 1).

  In such a boiler system, the combustion states of the plurality of boilers constituting the boiler group are controlled by the steam pressure measured at the steam header where steam generated by the plurality of boilers gathers. That is, when the required load increases, the amount of steam used increases, so the pressure measured at the steam header decreases. Then, the boiler system activates a predetermined boiler that is set to be activated in response to the reduced steam pressure. When the steam generation amount increases and the steam pressure measured in the steam header increases, the boiler system stops the activated boiler and decreases the steam generation amount.

  Therefore, when the required load (the pressure value measured at the steam header) repeatedly fluctuates across the threshold value for starting or stopping the predetermined boiler, the predetermined boiler is activated to supply steam. The state (steaming state) and the stop state are repeated (start / stop is repeated).

JP-A-11-270801

  By the way, when starting the boiler once stopped, it is necessary to remove the combustible component which stayed in the boiler, before starting combustion. Specifically, for example, in an oil fired boiler that uses oil as fuel, first, a pre-purge for operating the blower to remove combustible components is performed, and then combustion of fuel oil by the burner is started. Further, in a gas-fired boiler having a main burner and a pilot burner and using gas as fuel, first, the pilot burner is ignited and the blower is operated to remove the combustible components, and then the fuel from the main burner is used. Start gas combustion.

  Thus, when starting a boiler that is in a stopped state, it is necessary to perform pre-purge or pilot operation.Therefore, in a boiler system, when control that repeatedly starts and stops the boiler is performed, the required load is reduced. Responsiveness to fluctuations decreases.

  Accordingly, an object of the present invention is to provide a boiler system capable of improving the response to a required load fluctuation.

  The present invention is a boiler system comprising a boiler group having a plurality of boilers and a control unit that controls the boiler group, and the control unit receives the boiler stop instruction at a predetermined frequency, The present invention relates to a boiler system that shifts a boiler that has received a boiler stop instruction to a steam supply preparation state.

  Further, the boiler is a boiler capable of burning in a combustion state at multiple positions including a first combustion position and a second combustion position that is a combustion state higher than the first combustion position, and the control unit includes the first combustion position It is preferable to give the boiler stop instruction to the boiler located at one combustion position.

  Further, the control unit includes a main control unit, and a plurality of local control units that are provided in each of the plurality of boilers and control the plurality of boilers based on the control of the main control unit, and the local control unit When the boiler stop instruction is received from the main control unit at a predetermined frequency, it is preferable to shift the boiler that has received the boiler stop instruction to a steam supply preparation state.

  Further, the local control unit, when the number of times the boiler stop instruction is received from the main control unit reaches a predetermined number of times within a predetermined time, causes the boiler that has received the boiler stop instruction to transition to a steam supply preparation state. Is preferred.

Further, the steaming preparation state includes a pressure holding state in which the boiler is held in a pressurized state,
When the local control unit receives the boiler stop instruction from the main control unit at a predetermined frequency, the local control unit preferably shifts the boiler that has received the boiler stop instruction to the pressure holding state.

  Moreover, it is preferable that the said local control part stops this boiler, when a steaming instruction | indication is not output within the predetermined time, after making the said boiler transfer to the said steaming preparation state.

  According to the boiler system of the present invention, it is possible to improve the responsiveness to required load fluctuations.

It is a figure showing the outline of the boiler system concerning one embodiment of the present invention. It is a figure showing the outline of the boiler group concerning one embodiment of the present invention. It is a figure which shows the relationship between the combustion pattern and priority of each boiler which concerns on one Embodiment of this invention, and the steam pressure zone in a steam pressure control range. It is a flowchart which shows operation | movement of the boiler system which concerns on one Embodiment of this invention.

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

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

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

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

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

  Specifically, the demand load (steam consumption) increases due to an increase in demand for the steam use facility 18, and if the supply steam quantity is insufficient, the steam pressure inside the steam header 6 decreases. On the other hand, if the demand load (steam consumption) decreases due to a decrease in the demand of the steam use facility 18, and the supply steam amount becomes excessive, the steam pressure inside the steam header 6 increases. Therefore, the boiler system 1 can monitor the fluctuation of the required load based on the fluctuation of the vapor pressure measured by the vapor pressure sensor 7. Then, the boiler system 1 calculates a target evaporation amount corresponding to the consumed steam amount (required load) of the steam using facility 18 based on the steam pressure of the steam header 6.

Here, the several boiler 20 which comprises the boiler system 1 of this embodiment is demonstrated. FIG. 2 is a diagram showing an outline of the boiler group 2 according to the present embodiment.
The boiler 20 of this embodiment consists of a stage value control boiler having a plurality of staged combustion positions. A step-value control boiler controls the amount of combustion by selectively turning combustion on / off, adjusting the size of the flame, etc., and gradually changes the amount of combustion according to the selected combustion position. It is a boiler that can be increased or decreased.

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

  As shown in FIG. 2, the boiler 20 in the present embodiment includes a combustion stop position (0%), a low combustion position (50%) as a first combustion position, and a high combustion position (100% as a second combustion position). ), A so-called three-position controlled boiler 20 that can be combusted at three stages of combustion positions. In this case, if the combustion amount in the fuel state (high combustion state) at the high combustion position is taken as 1.0, the combustion amount of each boiler 20 can be changed in 0.5 increments.

  The N position control represents that the combustion amount of the step value control boiler can be controlled step by step to the N position including the combustion stop position. 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.

Moreover, in this embodiment, in each boiler 20, the state until it transfers from a combustion stop position to a low combustion position and the supply of steam (steaming) is started is called a steaming preparation state. This steam supply preparation state includes the following states (1) to (3).
(1) Continuous pilot combustion state: In a gas-fired boiler using a gas as fuel and having a pilot burner and a main burner, unburned inside the boiler 20 by burning the pilot burner while driving the blower A state in which the main burner can be ignited promptly when a combustion instruction is received, preventing gas (flammable components) from staying. The continuous pilot combustion state refers to a state where the pilot burner is burned at least when the combustion of the main burner is stopped. That is, the continuous pilot combustion state includes a case where the combustion of the pilot burner is stopped when the main burner is burning.
(2) Light wind purge state: In an oil-fired boiler that uses oil as fuel, the air blower is continuously driven to maintain the supply of air to the inside of the boiler 20 (can body), so that the inside of the boiler 20 is combustible. A state where the vaporized oil component, which is a component, is prevented from staying and the burner can be ignited promptly when a combustion instruction is received. The light air purge state includes a case where the blower is operated in a weaker state than when the burner is combusted, and a case where the blower is operated in the same state as when the burner is combusted.
(3) Pressure maintaining state: Steaming is not performed, but the pressure inside the boiler 20 is maintained, and when a combustion instruction is received, steaming can be started promptly.

  The steam supply preparation state is not limited to the above (1) to (3) states alone, but also the states (1) and (2) (the state in which continuous pilot combustion is performed while maintaining the pressure), and It includes the states (1) and (3) (the state in which the light air purge is performed while maintaining the pressure).

In the boiler group 2 described above, a plurality of combustion patterns are set that are combinations of the boilers 20 and their combustion positions. FIG. 3 is a diagram showing the relationship between the combustion pattern and priority of each boiler 20 according to the present embodiment, and the steam pressure zone in the steam pressure control range.
In the present embodiment, as shown in FIG. 3, the combustion pattern is “H” when the boiler is burned at the high combustion position (high combustion state), and is burned at the low combustion position (low combustion state). ) Is shown as “L”, and the combustion stop state is shown as “−”.

  As the combustion pattern, a pattern with a smaller combustion amount is selected as the vapor pressure detected by the vapor pressure sensor 7 becomes higher, and a pattern with a larger combustion amount is selected as the vapor pressure decreases. As shown in FIG. 3, in this embodiment, the vapor pressure control range is divided into seven vapor pressure zones A to G. Then, the boiler system 1 sets a corresponding combustion pattern, that is, a combustion state (combustion position) for each steam pressure zone, and determines the combustion amount depending on which pressure zone the steam pressure corresponds to. Seven combustion patterns are set corresponding to the seven vapor pressure zones.

  More specifically, as shown in FIG. 3, in the uppermost steam pressure zone A (when the required load is small), all the boilers 20 are located at the combustion stop position (−), and the lowest steam pressure. In the belt G (when the required load is large), all the boilers 20 are located at the high combustion position (H).

  A priority order is set for each of the boilers 20. 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 FIGS. 2 and 3, when the priority order of “1” to “3” is assigned to each of the No. 1 to No. 3 units of the boiler 20, the No. 1 priority is the highest and Lowest priority. This priority order is changed at predetermined time intervals (for example, 24 hour intervals) under the control of the main control unit 4 described later.

  In this embodiment, as shown in FIG. 3, when the vapor pressure decreases from the highest vapor pressure zone A toward the lowest vapor pressure zone G, the highest priority is given in normal control. After the boiler (No. 1 boiler) is changed from the combustion stop state (-) to the low combustion state (L), the next highest boiler (No. 2 boiler) is changed from the combustion stop state (-) to the low combustion state (-). The combustion state (L) is changed. After all the boilers 20 are changed to the low combustion state (L), the boiler 20 having the highest priority (here, No. 1 boiler) is changed from the low combustion state (L) to the high combustion state (H). The

Next, details of control of the combustion state of the plurality of boilers 20 by the boiler system 1 of the present embodiment will be described. The boiler system 1 of the present embodiment includes a main control unit 4 provided in the number control device 3 and a local control unit 25 provided in each of the plurality of boilers 20 as control units for controlling the combustion state of the boiler group 2. Prepare.
Based on the vapor pressure signal from the vapor pressure sensor 7, the number control device 3 calculates the required combustion amount of the boiler group 2 according to the required load and the combustion position (combustion state) of each boiler 20 corresponding to the required combustion amount. Then, the number control signal is transmitted to each boiler 20 (local control unit 25 described later). As shown in FIG. 1, the number control device 3 includes a main storage unit 5 and a main control unit 4.

  The main storage unit 5 includes instructions given to each boiler 20 under the control of the number control device 3 (main control unit 4), information such as the combustion state (combustion position) received from each boiler 20, and a plurality of boilers. 20 priority setting information, setting information related to priority change (rotation), and the like are stored.

  The main control unit 4 gives various instructions to the boilers 20 through the signal lines 16 and receives various data from the boilers 20 to determine the combustion states (combustion positions) of the three boilers 20. Control priority. When each boiler 20 receives a signal for changing the combustion position from the number control device 3, it controls the boiler 20 according to the instruction.

  As shown in FIG. 1, the boiler 20 includes a boiler body 21 in which combustion is performed, a local vapor pressure measurement unit 27 that measures the vapor pressure inside the boiler 20, a local storage unit 26, and a combustion position of the boiler 20 ( And a local control unit 25 for controlling the combustion state).

The local vapor pressure measurement unit 27 includes a vapor pressure sensor, and measures the vapor pressure inside the boiler 20.
The local storage unit 26 stores information such as the content of the combustion position change instruction issued from the number control device 3 (main control unit 4) to the boiler 20 (local control unit 25), the time when the change instruction is received, and the like. Remember.

The local control unit 25 changes the combustion position (combustion state) of the boiler 20 according to the required load. Specifically, the local control unit 25 determines the steam pressure inside the boiler 20 based on the number control signal transmitted from the number control device 3 via the signal line 16 or measured by the local steam pressure measurement unit 27. Based on the above, the combustion state of the boiler 20 is controlled.
Further, the local control unit 25 transmits a signal used in the number control device 3 to the number control device 3 via the signal line 16. The signals used in the number control device 3 include the steam pressure inside the boiler 20, the actual combustion state of the boiler 20, and other data.

  In this embodiment, the local control unit 25 issues a boiler stop instruction when the number of times the boiler stop instruction is received from the main control unit 4 reaches a predetermined number (for example, 5 times) within a predetermined time (for example, within 1 minute). Based on this, the boiler 20 is shifted to the steaming preparation state.

  Specifically, for example, in the boiler group 2 shown in FIG. 3, when both the No. 1 boiler and the No. 2 boiler are burning at the low combustion position (L), the value of the steam pressure measured by the steam header 6. However, when the measured value exceeds the upper limit value of the steam pressure zone C, the main control unit 4 issues a combustion stop instruction to the No. 2 boiler. Further, in this case, when the measured vapor pressure falls below the upper limit value of the vapor pressure zone C (lower limit value of the vapor pressure zone B), the main control unit 4 gives an instruction to burn the No. 2 boiler at the low combustion position. .

The local control unit 25 changes the combustion position of the boiler 20 based on an instruction from the main control unit 4. In addition, the local control unit 25 stores the content of the instruction received from the main control unit 4 and the time when the instruction is received in the local storage unit 26.
Then, when the number of boiler stop instructions stored in the local storage unit 26 reaches a predetermined number within a predetermined time, the local control unit 25 does not stop the boiler 20 even when receiving the boiler stop instruction. The boiler 20 is shifted to the steaming preparation state.

  Thereby, when the instruction | indication made to burn again in the low combustion position is given to the boiler 20 transferred to the steaming preparation state, the boiler 20 can start steaming immediately (it can transfer to a low combustion position). Therefore, the responsiveness to load fluctuation can be improved.

For example, when the boiler 20 is shifted to the pressure holding state as the steam supply preparation state, the boiler 20 maintains a state in which steaming can be started promptly, so that the boiler 20 is burned at the low combustion position. When the instruction is given, the time until the start of steaming can be shortened.
Further, when the boiler 20 is shifted to the continuous pilot combustion state as the steaming preparation state, the main burner can be burned without performing the pilot operation when the boiler 20 is combusted, so the steaming is started. Time to do can be shortened.
Further, when the boiler 20 is shifted to the light wind purge state as the steam supply preparation state, the burner can be burned without performing the pre-purge when the boiler 20 is combusted. You can save time.

Moreover, the local control part 25 stops this boiler 20, when a steaming instruction | indication is not given within predetermined time (for example, within 5 minutes), after making the boiler 20 transfer to a steaming preparation state.
That is, if the local control unit 25 does not receive an instruction to burn the boiler 20 at the low combustion position from the main control unit 4 within a predetermined time after the boiler 20 is shifted to the steam supply preparation state, The boiler 20 that has been shifted to the steam preparation state is shifted to the combustion stop position.
Thereby, when the instruction | indication of a combustion position change is no longer repeated with respect to the boiler 20 changed to the steaming preparation state in order to improve the responsiveness with respect to a load fluctuation, it was made to transfer to this steaming preparation state. The boiler 20 can be stopped.

Next, the operation of the boiler system 1 of the present embodiment will be described with reference to FIGS. FIG. 4 is a flowchart showing the operation of the boiler system 1.
Here, as shown in FIG. 2 and FIG. 3, when the priority orders “1” to “3” are assigned to the first to third machines of the boiler 20, the first boiler 20 and the second machine The steam pressure of the steam header 6 measured by the steam pressure sensor 7 is steam while the boiler 20 of the No. 3 burns at the low combustion position (L) and the boiler 20 of the No. 3 machine is positioned at the combustion stop position (−). The operation of the boiler system 1 when up and down is repeated across the upper limit value of the pressure band C will be described. In this state, the vapor pressure of the vapor header 6 measured by the vapor pressure sensor 7 is located in the range of the vapor pressure zone C shown in FIG.

  In this case, as shown in FIG. 4, first, in step ST <b> 1, the main control unit 4 monitors the vapor pressure of the vapor header 6 measured by the vapor pressure sensor 7. Here, when the vapor pressure of the vapor header 6 measured by the vapor pressure sensor 7 does not exceed the first threshold value which is the upper limit value of the vapor pressure zone C shown in FIG. 3, the process returns to step ST1. When the vapor pressure of the vapor header 6 measured by the vapor pressure sensor 7 exceeds the first threshold value, the process proceeds to step ST2.

  In step ST2, the main control unit 4 issues a combustion stop instruction to the local control unit 25 of the No. 2 boiler 20 having the lowest priority among the boilers 20 burning at the low combustion position. Then, the process proceeds to step ST3.

  In step ST <b> 3, the local control unit 25 of the No. 2 boiler 20 stores the content of the instruction received from the main control unit 4 and the received time in the local storage unit 26. Then, the process proceeds to step ST4.

  In step ST4, the local control unit 25 determines whether the frequency at which the combustion stop instruction is received exceeds a predetermined frequency. Specifically, based on the information stored in the local storage unit 26, the local control unit 25 sets the time from the combustion stop instruction n times before (for example, 4 times before) to the current combustion stop instruction for T1 time. It is determined whether it is less than (for example, 1 minute). If the local control unit 25 determines that the time from the nth previous combustion stop instruction to the current combustion stop instruction is less than T1 time, the process proceeds to step ST10. When the local control unit 25 determines that the time from the nth previous combustion stop instruction to the current combustion stop instruction is not less than T1 time, the process proceeds to step ST5.

  In step ST5, the local control unit 25 stops the combustion of the No. 2 boiler. Then, the process proceeds to step ST6.

  In step ST6, the main control unit 4 determines whether the vapor pressure of the vapor header 6 measured by the vapor pressure sensor 7 has fallen below the first threshold value. If the main control unit 4 determines that the vapor pressure has fallen below the first threshold, the process proceeds to step ST7. If the main control unit 4 does not determine that the vapor pressure has fallen below the first threshold value, the process returns to step ST6.

  In step ST7, the main control unit 4 issues an instruction to shift the No. 2 boiler 20 to the low combustion position. Then, the process proceeds to step ST8.

  In step ST <b> 8, the local control unit 25 of the No. 2 boiler 20 performs a pilot operation or pre-purges the stopped No. 2 boiler 20. Then, the process proceeds to step ST9.

  In step ST9, the local control unit 25 burns the No. 2 boiler 20 and shifts it to the low combustion position. Then, the process returns to step ST1.

  On the other hand, when the local control unit 25 determines in step ST4 that the time from the nth previous combustion stop instruction to the current combustion stop instruction is less than T1 hours, in step ST10, the local control unit 25 The No. 2 boiler 20 is shifted to the steaming preparation state. Here, the local control unit 25 shifts the No. 2 boiler 20 to the continuous pilot operation state or the light wind purge state. Then, the process proceeds to step ST11.

  In step ST11, the main control unit 4 determines whether the vapor pressure of the vapor header 6 measured by the vapor pressure sensor 7 has fallen below the first threshold value. If the main control unit 4 determines that the vapor pressure has fallen below the first threshold, the process proceeds to step ST12. If the main control unit 4 does not determine that the vapor pressure has fallen below the first threshold, the process proceeds to step ST14.

  In step ST12, the main control unit 4 issues an instruction to shift the No. 2 boiler 20 to the low combustion position. Then, the process proceeds to step ST13.

  In step ST13, the local control unit 25 burns the No. 2 boiler 20 without causing the pilot operation or the pre-purge to shift to the low combustion position. Then, the process returns to step ST1.

  On the other hand, in step ST11, when it is not determined by the main control unit 4 that the vapor pressure is lower than the first threshold value, in step ST14, the local control unit 25 of the No. 2 boiler 20 shifts to the steam supply preparation state. It is determined whether a predetermined time T2 has elapsed. If the local control unit 25 determines that T2 time has elapsed since the transition to the steaming preparation state, the process proceeds to step ST15. If the local control unit 25 does not determine that T2 time has elapsed since the transition to the steaming preparation state, the process returns to step ST11.

  In step ST <b> 15, the local control unit 25 stops the combustion of the No. 2 boiler 20. Then, the process of this flow ends.

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

  (1) The boiler system 1 includes a main control unit 4 that controls the boiler group 2 and a local control unit 25 provided in each of the plurality of boilers 20, and the local control unit 25 has a predetermined frequency. When the boiler stop instruction is received from the main control unit 4, the boiler 20 that has received the boiler stop instruction is shifted to the steam supply preparation state. As a result, when a boiler stop instruction is issued to the boiler 20 that is frequently started and stopped, the boiler 20 is shifted to the steaming preparation state. When it is put out, steaming can be started immediately (can shift to a low combustion position). Therefore, even when the required load repeatedly fluctuates across the threshold for starting or stopping the boiler 20, the responsiveness to the load fluctuation can be improved.

  (2) When the number of times the local control unit 25 has received the boiler stop instruction from the main control unit 4 reaches a predetermined number of times within a predetermined time, the boiler 20 is shifted to the steaming preparation state based on the boiler stop instruction. . As a result, when a boiler stop instruction is received, the contents of the instruction and the time when the instruction is received are stored in the local storage unit 26, so that the boiler 20 is started based on the information stored in the local storage unit 26. The frequency with which the stop is repeated can be easily determined.

  (3) When the local control unit 25 receives a boiler stop instruction from the main control unit 4 at a predetermined frequency, the boiler 20 is shifted to the pressure holding state. As a result, when a boiler stop instruction is issued to the boiler 20 that is frequently repeated, the boiler 20 can be kept in a pressure maintaining state where steaming can be started immediately. Can be improved.

(4) When the local control unit 25 receives a boiler stop instruction from the main control unit 4 at a predetermined frequency, the boiler 20 is shifted to the continuous pilot combustion state or the light wind purge state. Thereby, when this boiler 20 is burned, since the combustion of the boiler 20 can be started without performing a pilot operation or pre-purge, it is possible to shorten the time until the steam supply is started.
In addition, when the boiler 20 is in a continuous pilot combustion state or a light wind purge state, the driving of the blower that supplies air into the boiler 20 is continued. Here, driving and stopping of the blower are performed using an inverter. Therefore, when a boiler stop instruction is issued to the boiler 20 that is frequently started and stopped, the blower can be continuously driven by placing the boiler 20 in a continuous pilot combustion state or a light wind purge state. And it can prevent the stop from being repeated frequently. Therefore, since it is possible to prevent an excessive load from being applied to the inverter used for driving and stopping the blower, the life of the electric system such as the inverter can be extended.
Moreover, according to the performance of the inverter provided in each of the plurality of boilers 20, by setting the frequency of starting and stopping to shift the boiler 20 to the steaming preparation state, control according to the performance of each of the plurality of boilers 20 is performed. Yes.

  (5) After the boiler 20 is shifted to the steaming preparation state by the local control unit 25, the boiler 20 is stopped when the steaming instruction is not issued within the predetermined time T2. Thereby, when the instruction | indication of a combustion position change is no longer repeated with respect to the boiler 20 changed to the steaming preparation state in order to improve the responsiveness with respect to load fluctuation | variation, it was made to transfer to this steaming preparation state. The boiler 20 can be stopped. Therefore, since the boiler 20 which does not perform steam supply can be stopped, the operating efficiency of the boiler system 1 can be improved.

The preferred embodiment of the boiler system 1 of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and can be modified as appropriate.
For example, in this embodiment, although the boiler system 1 of this invention was applied to the boiler 20 of 3 position control, it is not restricted to this. That is, the boiler system 1 of the present invention may be applied to a two-position control (that is, only on / off) boiler or a four-position control boiler. When the boiler system of the present invention is applied to a four-position control boiler, the first combustion position corresponds to the low combustion position, and the second combustion position corresponds to the middle combustion position.

  Moreover, in this embodiment, although the frequency of the start / stop of the boiler 20 was determined based on the frequency | count of the boiler stop instruction | indication memorize | stored in the local memory | storage part 26, it is not restricted to this. That is, the frequency of boiler start / stop may be determined based on the number of instructions (steaming start instruction) for burning at the low combustion position stored in the local storage unit.

  Moreover, in this embodiment, when the local control part 25 receives the boiler stop instruction | indication from the main control part 4 with predetermined frequency, the boiler 20 which received the boiler stop instruction | indication by control of the local control part 25 is in a steaming preparation state. However, the present invention is not limited to this. That is, when the main control unit receives a boiler stop instruction from the local control unit at a predetermined frequency, the boiler that has received the boiler stop instruction under the control of the main control unit may be shifted to the steaming preparation state.

DESCRIPTION OF SYMBOLS 1 Boiler system 2 Boiler group 4 Main control part 20 Boiler 25 Local control part L Low combustion position (1st combustion position)
H High combustion position (second combustion position)

Claims (6)

A boiler system comprising a boiler group having a plurality of boilers, and a control unit that controls the boiler group,
The said control part is a boiler system which transfers the boiler which received this boiler stop instruction | indication to a steam supply preparation state, when a boiler stop instruction | indication is received with predetermined frequency. The boiler is a boiler capable of burning in a combustion state at multiple positions including a first combustion position and a second combustion position that is a combustion state higher than the first combustion position,
The boiler system according to claim 1, wherein the control unit issues the boiler stop instruction to the boiler located at the first combustion position. The control unit includes a main control unit, and a plurality of local control units that are provided in each of the plurality of boilers and control the plurality of boilers based on the control of the main control unit,
3. The boiler according to claim 1, wherein, when the local control unit receives the boiler stop instruction from the main control unit at a predetermined frequency, the boiler that has received the boiler stop instruction shifts to a steaming preparation state. 4. system.   The said local control part makes the boiler which received the said boiler stop instruction | indication shift to a steaming preparation state, when the frequency | count of receiving the said boiler stop instruction | indication from the said main control part reaches the predetermined number in predetermined time. The boiler system described in The steaming preparation state includes a pressure holding state in which the boiler is held in a pressurized state,
The boiler system according to claim 3 or 4, wherein, when the local control unit receives the boiler stop instruction from the main control unit at a predetermined frequency, the boiler system that has received the boiler stop instruction shifts to the pressure holding state. .   The local control unit according to any one of claims 3 to 5, wherein when the steaming instruction is not issued within a predetermined time after the boiler is shifted to the steaming preparation state, the boiler is stopped. Boiler system.

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