JP6303543B2 - Boiler system - Google Patents

Description

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

  There has been proposed a boiler system including a boiler group having a plurality of boilers that can be burned by changing the combustion rate, and a number control device that controls the combustion state of the boiler group according to a required load. In such a boiler system, a steam header that stores steam generated from a plurality of boilers is provided, and steam is supplied from the steam header to a load device.

Conventionally, as such a boiler system, a boiler of a step value control system capable of burning by changing the combustion rate stepwise has been widely used. However, in recent years, it is possible to burn by changing the combustion rate continuously. Boiler systems that use proportional control boilers are also becoming popular.
The stage value control type boiler is an N-position boiler that burns at a plurality of stages of combustion positions (for example, a three-position boiler that stops combustion, low combustion, high combustion, etc.). In the boiler, the combustion rate is changed stepwise (for example, every 50%). On the other hand, the proportional control type boiler refers to a boiler whose combustion rate can be changed in increments of 1%, for example, and can be finely adjusted as compared with a step value control type boiler, thereby improving pressure stability.

Here, in the boiler system constituted by the boilers of the step value control system, the unit control device presets the combustion pattern of each boiler and burns each boiler with the combustion pattern corresponding to the steam pressure of the steam header. Thus, the combustion state of the boiler group is controlled (see Patent Document 1).
Further, in a boiler system composed of proportional control boilers, the unit control device sets a target pressure in advance and calculates a control amount corresponding to the deviation between the steam pressure in the steam header and the target pressure. The combustion state of the boiler group is controlled (see Patent Document 2).

JP 2013-072609 A JP 2010-048662 A

  The combustion control methods described in Patent Documents 1 and 2 assume a state in which the boiler group is configured by only a stage value control type boiler or a proportional control type boiler. It was not assumed to be applied to a boiler group in which both boilers and proportional control boilers coexist.

In this regard, in recent years, switching from a step value control type boiler to a proportional control type boiler has been promoted, and when a part of a step value control type boiler is switched to a proportional control type boiler, A value control boiler and a proportional control boiler are mixed.
By the way, such a state where boilers of both control methods coexist occurs in the middle of switching, and a unit control device suitable for a state where boilers of both control methods coexist has been developed, and the existing number Switching from the control device is not preferable because it requires a large amount of money.

  Therefore, the present invention provides a group of boilers in which a step value control type boiler and a proportional control type boiler are mixed without changing an existing number control device (that is, a number control device suitable for a step value control type boiler). An object of the present invention is to provide a boiler system that can appropriately control the combustion state of the boiler.

  The present invention includes a boiler group including at least one proportional control boiler capable of burning by continuously changing the combustion rate, and control for controlling the combustion state of the boiler included in the boiler group at a plurality of stepwise combustion positions. The proportional control boiler sets a predetermined combustion rate among changeable combustion rates as a first combustion position, and sets a maximum combustion rate at which the proportional control boiler can burn. A first setting unit that sets the second combustion position is provided, and the control device burns at a plurality of stepwise combustion positions including the first combustion position and the second combustion position set by the first setting unit. As described above, the present invention relates to a boiler system that controls a combustion state of boilers included in the boiler group.

  The proportional control boiler is set with an eco operation point that is a combustion rate at which the boiler efficiency is highest, and the first setting unit sets a combustion rate corresponding to the eco operation point to the first combustion position. The control device controls the combustion state of the boilers included in the boiler group so as to burn at the three-stage combustion positions of combustion stop, low combustion and high combustion, and sets the first combustion position to The proportional control boiler may be controlled with the low combustion position and the second combustion position as the high combustion position.

  The proportional control boiler may further include a second setting unit that sets a combustion rate corresponding to the eco-operation point based on a feed water temperature.

  Further, the proportional control boiler is set with an eco operation zone that is in a combustion rate range in which the boiler efficiency is higher than a predetermined threshold, and the first setting unit corresponds to an upper limit value of the eco operation zone. The combustion rate is set as the first combustion position, and the control device determines the combustion state of the boilers included in the boiler group so that combustion is performed at four combustion positions: combustion stop, low combustion, medium combustion, and high combustion. The proportional control boiler may be controlled with the first combustion position as the combustion position of the middle combustion and the second combustion position as the combustion position of the high combustion.

  The first setting unit sets a combustion rate corresponding to a lower limit value of the eco-operation zone as a third combustion position, and the control device sets the third combustion position as the low combustion combustion position as the proportional combustion position. It is good also as controlling a control boiler.

  Further, the first setting unit sets a minimum combustion rate at which the proportional control boiler can burn as a third combustion position, and the control device performs the proportional control with the third combustion position as the low combustion combustion position. It is good also as controlling a boiler.

  The proportional control boiler may further include a second setting unit that sets a combustion rate corresponding to the eco-operation zone based on a feed water temperature.

  ADVANTAGE OF THE INVENTION According to this invention, the combustion state of the boiler group in which the boiler of a step value control system and the boiler of a proportional control system can be controlled appropriately using the number control apparatus suitable for the boiler of a step value control system. .

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 of each boiler which concerns on one Embodiment of this invention, and the steam pressure zone of a steam header. It is explanatory drawing which shows control of the boiler by the local control part based on a number control signal. It is a block diagram which shows the function structure of the local control part of the proportional control boiler which comprises a boiler group. It is a figure which shows an example of the combustion position setting by a 1st setting part. It is a figure which shows an example of the combustion position setting by a 1st setting part. It is a figure which shows an example of the setting of the eco driving point by the 2nd setting part, and an eco driving zone.

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. FIG. 1 is a diagram showing an outline of a boiler system according to an embodiment of the present invention.
As shown in FIG. 1, the boiler system 1 includes a boiler group 2 including a plurality (three) of boilers 20, a steam header 6 that collects steam generated in the plurality of boilers 20, and the steam header 6. A vapor pressure sensor 7 for measuring the internal pressure and a number control device 3 having a control unit 4 for controlling the combustion state of the boiler group 2 are provided.

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

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

  The number control device 3 is electrically connected to the plurality of boilers 20 through the signal line 16. The number control device 3 controls the combustion state of the boiler group 2 by controlling the combustion position of each boiler 20 based on the steam pressure inside the steam header 6 measured by the steam pressure sensor 7. The number control device 3 includes a storage unit 5 and a control unit 4.

The storage unit 5 stores the content of instructions given to each boiler 20 under the control of the number control device 3 (control unit 4), information such as the combustion position received from each boiler 20, combustion patterns and priorities described later. Setting information, setting information related to priority order change (rotation), and the like are stored.
The control unit 4 gives various instructions (number control signal) to each boiler 20 via the signal line 16 and receives various data from each boiler 20 to determine the combustion state of the three boilers 20. Control priority. When each boiler 20 receives a signal for changing the combustion state from the number control device 3, it controls the boiler 20 according to the instruction.

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

  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 the required steam amount (required steam amount) according to the consumed steam amount (required load) of the steam using equipment 18 based on the steam pressure of the steam header 6, and The boiler group 2 is burned so that the steam is supplied to 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 one embodiment of the present invention.
The boiler group 2 of the present embodiment is a mixture of a step value control boiler having a plurality of stepwise combustion positions and a proportional control boiler capable of continuously changing the combustion rate. In FIG. 2, the No. 1 boiler and the No. 2 boiler are step value control boilers, and the No. 3 boiler is a proportional control boiler.

  Here, the stage value control boiler refers to an N position boiler that burns at a plurality of stages of combustion positions by selectively turning on / off combustion or adjusting the size of the flame. In the step value control boiler, the combustion rate is changed step by step. 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. FIG. 2 shows a three-position boiler having a combustion stop position (−), a low combustion position (L), and a high combustion position (H), but the number of combustion positions is four (combustion stop position, low combustion position). Position, medium combustion position and high combustion position) or more.

  The proportional control boiler is a boiler in which the combustion amount can be continuously controlled at least in the range from the minimum combustion state S1 in which the combustion of the boiler can be maintained to the maximum combustion state S2 in which the boiler can be safely combusted. It is. It should be noted that the continuous control of the combustion amount means that a calculation or signal in the local control unit 22 to be described later is a digital method and is handled in stages (for example, the output (combustion amount) of the boiler 20 in predetermined unit increments). Even when the output is controlled).

The change of the combustion state between the combustion stop state S0 and the minimum combustion state S1 of the proportional control boiler is controlled by turning on / off the combustion of the boiler 20 (burner). In the range from the minimum combustion state S1 to the maximum combustion state S2, the combustion amount can be controlled continuously.
More specifically, a unit steam amount U that is a unit of variable steam amount is set in the proportional control boiler. As a result, the proportional control boiler can vary the steam amount in units of unit steam amount U in the range from the minimum combustion state S1 to the maximum combustion state S2. The unit steam amount U can be appropriately set according to the steam amount (maximum steam amount) in the maximum combustion state S2 of the proportional control boiler. From the viewpoint of improving the followability of the output steam amount to the required steam amount in the boiler system 1, It is preferably set to 0.1% to 20% of the maximum steam amount of the proportional control boiler, and more preferably set to 1% to 10%.

  Moreover, the priority order is set to each of the plurality of boilers 20. The priority order is used to select the boiler 20 that performs a combustion instruction or a combustion stop instruction. The priority order can be set, for example, using an integer value so that the lower the numerical value, the higher the priority order. As shown in FIG. 2, when the priorities of “1” to “3” are assigned to the first to third units of the boiler 20, the first unit has the highest priority and the third unit has the highest priority. Lowest. This priority order is changed at predetermined time intervals (for example, 24 hour intervals) under the control of the control unit 4 described later.

In the boiler group 2 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 of each boiler according to an embodiment of the present invention and the steam pressure zone of the steam header 6 in the pressure control range.
The combustion pattern consists of the type of boiler and the combustion position of the boiler. In FIG. 3, “H” indicates that the boiler 20 is to be burned at the high combustion position, “L” indicates that the boiler 20 is to be burned at the low combustion position, and “−” indicates that the boiler 20 is at the combustion stop position. The combustion positions are shown in order from the left according to the priority order of 20. That is, [(H) (L) (L)] of the combustion pattern E is a state where the boiler 20 with the first priority is burned at the high combustion position, and the boiler 20 with the second priority is burned at the low combustion position. It shows that it is set as a state and it is set as the state which burns the boiler 20 of the priority 3rd in a low combustion position.

  As the combustion pattern, a pattern is selected in which the steam amount output from the boiler group 2 is smaller as the pressure of the steam header 6 is higher, that is, the required load is smaller, and the required load is lower as the pressure of the steam header 6 is lower. A pattern with a larger amount of steam output from the boiler group 2 is selected as it increases.

And the number control apparatus 3 controls the combustion state of the boiler group 2 with the combustion pattern corresponding to the steam pressure zone to which the steam pressure of the steam header 6 belongs.
In FIG. 3, seven combustion patterns are set corresponding to the seven steam pressure zones. This is because the step-value control boiler is a three-position boiler, and the step-value control boiler is set to four. In the case of a position boiler or the like, the number of combustion patterns corresponding to the corresponding combustion position is set.

Returning to FIG. 1, each of the plurality of boilers 20 includes a boiler body 21 in which combustion is performed, and a local control unit 22 that controls the combustion state of the 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 controls the combustion state of the boiler 20 according to the required load. Specifically, the local control unit 22 controls the combustion state of the boiler 20 based on the number control signal transmitted from the number control device 3 via the signal line 16. Further, the local control unit 22 transmits a signal used in the number control device 3 to the number control device 3 via the signal line 16. Examples of the signal used in the number control device 3 include the actual combustion position of the boiler 20 and other data.

  Here, the control of the local control unit 22 when the number control signal is transmitted from the number control device 3 will be described. FIG. 4 is an explanatory diagram showing the control of the boiler 20 by the local control unit 22 based on the number control signal. In FIG. 4, it is assumed that the number control signal of the combustion pattern E [(H) (L) (L)] is transmitted.

  In the combustion pattern E, the boiler 20 with the first priority is burned at the high combustion position (H), and the boilers 20 with the second and third priority are burned at the low combustion position (L). Here, as shown in FIG. 2, the boilers 20 having the first and second priority ranks are a No. 1 boiler and a No. 2 boiler, and are a combustion stop position (−), a low combustion position (L), and a high combustion position (H ) Is a step value control boiler set. Therefore, based on the signal from the number control device 3, the local control unit 22 of the No. 1 boiler burns the No. 1 boiler at the high combustion position (H), and the local control unit 22 of the No. 2 boiler is the No. 2 boiler. Is burned at the low combustion position (L).

  On the other hand, the boiler 20 with the third highest priority is a proportional control boiler, and has a combustion stop position (−), a low combustion position (L), and a high combustion position (H) like the No. 1 and No. 2 boilers. Not set. Therefore, even if the local control unit 22 of the No. 3 boiler is instructed by the unit control device 3 to burn at the low combustion position (L), the No. 3 boiler cannot be burned appropriately.

Then, the local control part 22 of the proportional control boiler (No. 3 boiler) of this embodiment sets the predetermined combustion rate among the combustion rates which the boiler 20 can change as a combustion position of a step value control boiler, and is a unit control device. In response to the signal from 3, the boiler 20 is burned at the burning rate.
Accordingly, the number control device 3 can appropriately control the combustion state of the boiler group in which the step value control boiler and the proportional control boiler are mixed without changing the number control device 3.

  FIG. 5 is a diagram illustrating a functional configuration of the local control unit 22 of the proportional control boiler. The local control unit 22 of the proportional control boiler includes a first setting unit 23 and a second setting unit 24.

  The first setting unit 23 sets the maximum combustion rate (maximum combustion state S2) at which the proportional control boiler can burn as the high combustion position (H) of the step value control boiler, and sets the combustion rate at which the proportional control boiler can burn. The predetermined combustion rate is set as a predetermined combustion position of the step value control boiler. Although the setting by the first setting unit 23 can be arbitrarily performed, it is preferably set in consideration of the efficiency of the proportional control boiler and the ease of controlling the number of units by the number control device 3 (pressure stability).

Here, an example of setting by the first setting unit 23 will be described with reference to FIGS.
With reference to FIG. 6 (1), the boiler 20 usually has different fuel efficiency depending on the combustion rate. Hereinafter, the combustion rate at which the boiler 20 burns most efficiently is referred to as an eco-operation point, and the range of the combustion rate in which the thermal efficiency of the boiler 20 is higher than a predetermined value (for example, a predetermined ratio of maximum efficiency) is referred to as an eco-operation zone. .

  Referring to FIGS. 6 (2a, 2b), when the proportional control boiler is set as a three-position step value control boiler, the combustion stop position (−) is the combustion rate 0%, and the high combustion position (H) is the maximum combustion rate. Since it may be set to (100%), the setting of the low combustion position (L) becomes a problem.

  With reference to FIG. 6 (2a), since the thermal efficiency of the proportional control boiler is highest at the eco-operation point, the first setting unit 23 sets the combustion rate corresponding to the eco-operation point as the low combustion position (L). Thereby, the efficiency of a proportional control boiler can be improved.

  With reference to FIG. 6 (2b), in order to improve the pressure stability of the boiler group 2, it is preferable that the combustion rate of the boiler group 2 can be changed finely. Therefore, the first setting unit 23 sets a minimum combustion rate (combustion rate corresponding to the minimum combustion state S1) at which the proportional control boiler can burn as the low combustion position (L). Thereby, the pressure stability of the boiler group 2 can be improved.

  Referring to FIG. 7 (3a, 3b, 3c), when the proportional control boiler is set as a 4-position step value control boiler, the setting of the low combustion position (L) and the middle combustion position (M) becomes a problem.

  Referring to FIG. 7 (3a), the eco operation zone is a range of the combustion rate at which the proportional control boiler burns with an efficiency equal to or higher than a predetermined efficiency. Therefore, the first setting unit 23 sets the combustion rate corresponding to the upper limit value of the eco-operation zone as the middle combustion position (M). Thereby, even if it is a case where it combusts in a middle combustion position (M), it will combust with the efficiency more than predetermined efficiency, and it can raise the efficiency of a proportional control boiler.

  Referring to FIG. 7 (3b), similarly, first setting unit 23 sets the combustion rate corresponding to the lower limit value of the eco-operation zone as the low combustion position (L). Thereby, even if it is a case where it combusts in a low combustion position (L), it will combust with efficiency more than predetermined efficiency, and it can raise the efficiency of a proportional control boiler.

  Referring to FIG. 7 (3c), the first setting unit 23 sets not the lower limit value of the eco-operation zone but the minimum combustion rate at which the proportional control boiler can burn as the low combustion position (L). Thereby, the combustion rate of the boiler group 2 can be changed finely, and the pressure stability of the boiler group 2 can be improved.

  6 and 7 are merely examples, and other combustion rates of the proportional control boiler may be set as combustion positions in the step value control boiler. For example, the predetermined combustion position may be set with respect to the combustion rate of the proportional control boiler so that the intervals between the plurality of combustion positions of the step value control boiler are equal. That is, when the proportional control boiler is set as a three-position step value control boiler, the combustion rate is 0%, the combustion stop position (-), the combustion rate 50% is the low combustion position (L), and the combustion rate 100% is high. In the case of setting as a combustion position (L) and a 4-position step value control boiler, a combustion rate of 0% is set to the combustion stop position (-), a combustion rate of 33% is set to the low combustion position (L), and the combustion rate is set to 67. % May be set as the middle combustion position (M), and the combustion rate 100% may be set as the high combustion position (L).

Returning to FIG. 4, the second setting unit 24 sets the combustion rate corresponding to the eco-operation point and the combustion rate corresponding to the upper limit value and the lower limit value of the eco-operation zone based on the feed water temperature to the boiler 20. Usually, the thermal efficiency of the boiler 20 varies depending on the temperature of the water supplied to the boiler 20. This is because the degree of decrease in the temperature of the combustion gas varies depending on the feed water temperature, and the ease with which condensed water (drain water) is generated varies.
Then, the 2nd setting part 24 sets the combustion rate corresponding to an eco-operation point and an eco-operation zone based on feed water temperature. Specifically, as shown in FIG. 8, the second setting unit 24 sets the combustion rate corresponding to the eco-operation point and the eco-operation zone when the feed water temperature is low (for example, about 15 ° C.), and the feed water temperature is normal. Is set to be lower than the combustion rate corresponding to the eco driving point or eco driving zone (for example, about 40 ° C.) (see FIGS. 8 (1) and (2)).
Then, the first setting unit 23 sets a predetermined combustion position for the combustion rate of the proportional control boiler according to the setting of the second setting unit 24.

  In addition, acquisition of water supply temperature is realizable by providing a water temperature measuring meter in water sources, such as a water supply tank, and acquiring the water temperature information which this water temperature measuring device measured via the communication line.

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

(1) In the boiler system 1 of the present embodiment, the boiler group 2 is configured by mixing the step value control boiler and the proportional control boiler, and the predetermined combustion rate is set to the first combustion position in the local control unit 22 of the proportional control boiler. And a first setting unit 23 that sets the maximum combustion rate as the second combustion position. Then, the number control device 3 that controls the combustion state of the boiler group 2 performs proportional control so that combustion is performed at a plurality of stepwise combustion positions including the first combustion position and the second combustion position set by the first setting unit 23. Control the combustion state of the boiler.
According to such a configuration, the proportional control boiler is handled as a stage value control boiler that burns at a plurality of staged combustion positions including the first combustion position and the second combustion position. Without adding any change, it is possible to appropriately control the combustion state of the boiler group 2 in which the step value control boiler and the proportional control boiler are mixed.

(2) In the proportional control boiler, an eco operation point that is the combustion rate at which the boiler efficiency is highest is set, and the first setting unit 23 sets the combustion rate corresponding to the eco operation point as the first combustion position. The number control device 3 is configured to control the proportional control boiler with the first combustion position as the low combustion position and the second combustion position as the high combustion position.
According to such a configuration, the proportional control boiler can be handled as a three-position boiler, and the eco-operation point is set as a low combustion combustion position, so that the proportional control boiler can be burned efficiently.

(3) The local control unit 22 of the proportional control boiler is configured to include a second setting unit 24 that sets the combustion rate corresponding to the eco-operation point based on the feed water temperature.
According to such a configuration, since the eco operation point corresponding to the feed water temperature is set as the first combustion position, the proportional control boiler can be burned efficiently regardless of the feed water temperature.

(4) In the proportional control boiler, an eco operation zone that is a range of a combustion rate in which the boiler efficiency is higher than a predetermined threshold is set, and the first setting unit 23 performs combustion corresponding to the upper limit value of the eco operation zone. The number control device 3 is configured to control the proportional control boiler with the first combustion position as the combustion position for medium combustion and the second combustion position as the combustion position for high combustion.
According to such a configuration, the proportional control boiler can be handled as a four-position boiler, and a combustion rate (upper limit value of the eco-operation zone) that is equal to or higher than a predetermined efficiency is set as a combustion position for medium combustion. Can be burned efficiently.

(5) The first setting unit 23 sets the combustion rate corresponding to the lower limit value of the eco-operation zone as the third combustion position, and the number control device 3 sets the third combustion position as the low combustion combustion position and is a proportional control boiler. It was set as the structure which controls.
According to such a configuration, the combustion rate of the predetermined efficiency or higher (the lower limit value of the eco-operation zone) is set as the low combustion combustion position, so that the proportional control boiler can be efficiently burned.

(6) The first setting unit 23 sets the minimum combustion rate at which the proportional control boiler can combust as the third combustion position, and the unit control device 3 sets the third combustion position as the low combustion combustion position and sets the proportional control boiler to the proportional control boiler. It was set as the structure controlled.
According to such a structure, the combustion rate in the whole boiler group 2 can be changed finely, and the pressure stability of the boiler group 2 can be improved.

(7) The local control unit 22 of the proportional control boiler is configured to include a second setting unit 24 that sets the combustion rate corresponding to the eco-operation zone based on the feed water temperature.
According to such a configuration, since the upper limit value and the lower limit value of the eco-operation zone according to the feed water temperature are set as the predetermined combustion position, the proportional control boiler can be burned efficiently regardless of the feed water temperature.

As mentioned above, although one preferable embodiment of the boiler of this invention was described, this invention is not restrict | limited to embodiment mentioned above, It can change suitably.
For example, although the boiler system 1 which consists of the three boilers 20 was demonstrated in the said embodiment, the number of the boilers 20 with which the boiler system 1 is provided is not restricted to three units | sets, and two or four or more boilers 20 are provided. It is good as well. Further, the number of proportional control boilers is not limited to one, and it is sufficient if a step value control boiler and a proportional control boiler are mixed, and two or more proportional control boilers may be provided.

DESCRIPTION OF SYMBOLS 1 Boiler system 2 Boiler group 20 Boiler 22 Local control part 23 1st setting part 24 2nd setting part 3 Number control device

Claims (7)

A boiler group including at least one proportional control boiler capable of burning by continuously changing the combustion rate, and a control device for controlling a combustion state of the boiler included in the boiler group at a plurality of stepwise combustion positions; A boiler system comprising:
In the proportional control boiler, an eco operation point that is a combustion rate at which the boiler efficiency is the highest is set,
The proportional control boiler sets a combustion rate corresponding to the eco-operation point among the changeable combustion rates as a first combustion position, and sets a maximum combustion rate at which the proportional control boiler can burn as a second combustion position. A first setting unit for setting;
The control device burns the proportional control boiler included in the boiler group so as to burn at a plurality of stepwise combustion positions including the first combustion position and the second combustion position set by the first setting unit. Control the state,
Boiler system. The control device controls the combustion state of the boilers included in the boiler group so that combustion is performed at three combustion positions of combustion stop, low combustion, and high combustion, and the first combustion position is set to the low combustion combustion. Position, controlling the proportional control boiler with the second combustion position as the combustion position of the high combustion,
The boiler system according to claim 1. The proportional control boiler includes a second setting unit that sets a combustion rate corresponding to the eco-operation point based on a feed water temperature;
The boiler system according to claim 1 or 2, further comprising: A boiler group including at least one proportional control boiler capable of burning by continuously changing the combustion rate, and a control device for controlling a combustion state of the boiler included in the boiler group at a plurality of stepwise combustion positions; A boiler system comprising:
In the proportional control boiler, an eco operation zone that is a range of a combustion rate in which the boiler efficiency is higher than a predetermined threshold is set,
The proportional control boiler sets the combustion rate corresponding to the upper limit value of the eco-operation zone among the changeable combustion rates as the first combustion position, and sets the maximum combustion rate at which the proportional control boiler can burn to the second combustion rate. A first setting unit for setting the combustion position;
The control device controls the combustion state of the boilers included in the boiler group so that combustion is performed at four combustion positions of combustion stop, low combustion, medium combustion, and high combustion, and the first combustion position is set to the middle. Controlling the proportional control boiler with the combustion position of combustion, the second combustion position as the combustion position of high combustion,
Boiler system. The first setting unit sets a combustion rate corresponding to a lower limit value of the eco-operation zone as a third combustion position,
The control device controls the proportional control boiler with the third combustion position as the low combustion combustion position.
The boiler system according to claim 4. The first setting unit sets a minimum combustion rate at which the proportional control boiler can burn as a third combustion position,
The control device controls the proportional control boiler with the third combustion position as the low combustion combustion position.
The boiler system according to claim 4. The proportional control boiler includes a second setting unit that sets a combustion rate corresponding to the eco-operation zone based on a feed water temperature;
The boiler system according to claim 4, further comprising:

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