JP2014092356A - Boiler system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boiler system for fixedly controlling pressure in a load unit using steam.SOLUTION: A boiler system 1 includes a unit count control apparatus 3 for controlling a combustion state of a boiler group 2 and storing steam with a target pressure in a steam header 6 and is configured to supply steam stored in the steam header 6 to a plurality of load units A1, A2, A3. The unit count control apparatus 3 includes: a storage part 5 for storing a required pressure P of steam to be used in each of the load units A1, A2, A3; using unit specification means 41 for specifying a steam using load unit using steam; supply amount acquisition means 42 for acquiring a supply steam amount (flow rate V) to the steam using load unit; pressure loss calculation means 43 for calculating pressure loss ΔP following steam supply to the steam using load unit on the basis of a pressure loss coefficient and a supplied steam amount of a steam pipe; and target value setting means 44 for setting a target pressure TP on the basis of the required pressure P and the pressure loss ΔP.

Description

  The present invention relates to a boiler system that supplies steam to a plurality of load devices.

Conventionally, as a boiler system that controls the combustion status of boilers based on fluctuations in the required load, followability to fluctuations in the required load is controlled by controlling the amount of steam generated by increasing or decreasing the combustion quantity of multiple boilers in stages. A boiler system with an improved level is known.
Many ideas about combustion control in such a boiler system have been made so far. For example, in Patent Document 1, a plurality of burning boilers are operated at an equal load factor, and are combusted. When the number of boilers varies, a control method for a proportional control boiler has been proposed in which all the boilers burning after the variation are operated at an equal load factor.

Japanese Patent Laid-Open No. 11-132405

By the way, the conventional combustion control has generally attempted to adjust the required load and the boiler combustion by monitoring the pressure of the steam header that stores the steam generated by the boiler.
Specifically, referring to FIG. 8A, a steam pressure sensor 7 is installed in the steam header 6, and when a pressure lower than the target pressure is detected by the steam pressure sensor 7, the required load is detected. It is determined that (the amount of steam used in the load devices A11, A12, A13) has increased, and the combustion amount of the boiler 20 is increased. On the other hand, when a pressure higher than the target pressure is detected by the vapor pressure sensor 7, it is determined that the required load has decreased, and the combustion amount of the boiler 20 is decreased. In the combustion control in the boiler system, the pressure of the steam header is maintained at the target pressure by such increase and decrease of the combustion amount.

At this time, the target pressure is set by adding a safety factor in consideration of pressure loss associated with steam supply to the steam pressure (hereinafter referred to as “required pressure”) required when using steam in the load device. This ensures safety in equipment design.
Specifically, referring to FIG. 8 (1), in the conventional boiler system, a steam pipe L is provided as a supply path to the load devices A11, A12, A13, and the pressure loss in the steam pipe L is taken into consideration. The target pressure is set.

However, in the conventional boiler system, since only the pressure of the steam header is monitored, the pressure loss of the steam pipe L cannot be properly managed.
For example, referring to FIG. 8 (2), pressure loss occurs in the steam pipe L11 that supplies steam to the load apparatus A11, the steam pipe L12 that supplies steam to the load apparatus A12, and the steam pipe L13 that supplies steam to the load apparatus A13. Consider the case where each is different. In the conventional boiler system, for example, the steam pipe L11, L12, L13 is the steam pipe having the largest pressure loss coefficient, and the steam pipe L is supplied with an average flow rate of steam. The target pressure is set in consideration of loss. For ease of explanation, it is assumed that the pressure loss coefficient of the steam pipe L11 is the smallest, the pressure loss coefficient of the steam pipe L12 is the next smallest, and the pressure loss coefficient of the steam pipe L12 is the largest.

Here, when it is considered as a steam system including a load device, it is important to control the pressure of the steam reaching the load device that actually uses the steam to be constant.
In this regard, referring to FIG. 8 (2), when the steam is used in the load device A11 while the steam is not used in the load devices A12 and A13, the target pressure of the steam header 6 is set by the conventional method. Then, the target pressure is set in consideration of the pressure loss of the steam pipe L13 through which no steam flows. Since the pressure loss of the steam pipe L13 is higher than the pressure loss of the steam pipe L11, the target pressure of the steam header 6 is set higher than necessary. As a result, the pressure of the steam reaching the load device A11 is the required pressure of the load device A11. It will be higher than.
Therefore, in a situation where steam is used only in the load device A11, it is preferable to lower the target pressure and operate the boiler efficiently. However, in the conventional method, the target pressure is set regardless of whether steam is used. Therefore, it was not possible to supply steam having a pressure suitable for a load device using steam.

  Then, an object of this invention is to provide the boiler system which controls the pressure in the load apparatus using steam uniformly, and as a result, enables efficient combustion control of a boiler.

  (1) A plurality of boilers combustible at stepwise combustion positions, a steam header for storing steam generated from the plurality of boilers, and a pressure of the steam stored in the steam header so as to become a target pressure value A boiler system that supplies steam to the plurality of load devices from the steam header via supply paths having different pressure losses, the control device including the plurality of load devices. Storage means for storing a required pressure of steam used every time, use device specifying means for specifying a steam use load device using steam among the plurality of load devices, and supply steam to the steam use load device Accompanied with the supply of steam to the steam use load device based on the supply amount acquisition means for acquiring the amount, the pressure loss coefficient of the supply path corresponding to the steam use load device and the supply steam amount Boiler system comprising a pressure loss calculating means for calculating the force loss, the required pressure and on the basis of the pressure loss corresponding to the steam-using load device, and a target value setting means for setting the target pressure value.

  According to the boiler system of (1), the steam at the target pressure corresponding to the required pressure of the steam load device that uses steam is stored in the steam header. At this time, the target pressure of the steam header is set in consideration of the pressure loss when supplying steam to the steam use load device in addition to the required pressure. The steam supplied from the steam header decreases in pressure due to the pressure loss until it reaches the steam load device, but since the pressure loss is added to the target pressure itself, the steam that reaches the steam load device This is the required pressure of the steam load device. Thereby, the pressure in the steam load device that uses steam can be controlled to be constant. As a result, the pressure of the steam header can be suppressed and the boiler can be controlled efficiently compared to the conventional method of setting the target pressure in consideration of the safety factor unrelated to the use of steam.

(2) The apparatus according to (1), further including a flow meter that measures a flow rate of steam flowing through the supply path, wherein the supply amount acquisition unit acquires the supply steam amount based on the flow rate measured by the flow meter. Boiler system.
(3) The storage unit stores a steam usage amount for each of the plurality of load devices, and the supply amount acquisition unit acquires the supply steam amount based on the steam usage amount corresponding to the steam use load device. The boiler system according to (1).

  The steam consumption (flow rate V) for calculating the pressure loss up to the steam load device may be measured by a flow meter as in the boiler system of (2), and the boiler system of (3) Thus, it is good also as acquiring from the steam usage-amount for every load apparatus.

(4) The boiler system according to any one of claims 1 to 3, wherein the use device specifying unit specifies the steam use load device by receiving an operation signal from the load device.
(5) The apparatus further includes an air supply valve that connects or disconnects the steam header and the supply path, and the use device specifying means is supplied with steam via the supply path connected by the air supply valve. The boiler system according to any one of (1) to (3), wherein a load device is specified as the steam-use load device.

  In addition, the steam load device may be specified based on an operation signal from the load device as in the boiler system of (4), or the open air supply valve as in the boiler system of (5). It is good also as specifying the load apparatus located downstream as a steam use load apparatus.

(6) When there are a plurality of steam use load devices that use steam, the target value setting means calculates the added value of the steam use load device having the largest added value obtained by adding the required pressure and the pressure loss. The boiler system according to any one of (1) to (5), which is set as the target pressure value.
(7) When there are a plurality of steam use load devices that use steam, the target value setting means calculates the sum value of the steam use load device that has the smallest sum of the required pressure and the pressure loss. The boiler system according to any one of (1) to (5), which is set as the target pressure value.
(8) The target value setting means, when there are a plurality of the steam use load devices using steam, an average value in the plurality of steam use load devices of the added value obtained by adding the required pressure and the pressure loss Is set as the target pressure value, the boiler system according to any one of (1) to (5).

  Further, when there are a plurality of steam load devices, the one with the largest sum of the required pressure and the pressure loss as in the boiler system of (6) may be set as the target pressure, (7) It is good also as setting a target pressure as a thing with the smallest addition value like the boiler system of (8), and setting the average value of the addition value in several steam use load apparatuses as a target pressure like the boiler system of (8). It is good as well.

  ADVANTAGE OF THE INVENTION According to this invention, the boiler system which controls the pressure in the load apparatus which uses a vapor | steam uniformly, and enables the efficient combustion control of a boiler as a result can be provided.

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 functional block diagram which shows the structure of a control part. It is a figure which shows the structure of a memory | storage part. It is a mimetic diagram showing an example of operation of a boiler system concerning one embodiment of the present invention. It is a flowchart which shows the flow of a process of the boiler system which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of operation | movement of the conventional boiler system.

Hereinafter, preferred embodiments of the boiler system of the present invention will be described with reference to the drawings. First, the overall configuration of the boiler system 1 of the present invention will be described with reference to FIG.
The boiler system 1 includes a boiler group 2 including a plurality of boilers 20, a steam header 6 that collects steam generated in the plurality of boilers 20, and a steam pressure sensor 7 that measures the pressure inside the steam header 6. And a unit control device 3 having a control unit 4 that controls the combustion state of the boiler group 2, and supplies the generated steam to the load device group A.

The load device group A is composed of a plurality of load devices A1, A2 and A3 (three in this embodiment), and is connected to the steam header 6 via steam pipes L1 and L2 as supply paths through which steam flows. Is done. Each load device A 1, A 2, A 3 is a facility that is operated by steam from the steam header 6.
Each of the steam pipes L1 and L2 connects the steam header 6 and the load device group A, and supplies steam from the steam header 6 to the load device group A. Specifically, the steam pipe L1 is a pipe that supplies steam from the steam header 6 to the load apparatus A1, and the steam pipe L2 is a pipe that supplies steam from the steam header 6 to the load apparatuses A2 and A3. . As shown in FIG. 1, the steam pipe L2 branches into steam pipes L2a and L2b on the way, the steam pipe L2a supplies steam to the load device A2, and the steam pipe L2b steams to the load device A3. Supply. Here, it is known that in pipes through which steam flows, the pressure loss coefficient varies depending on factors such as pipe diameter, pipe extension, pipe shape (bend, enlargement / reduction, etc.), presence / absence / number / shape of valves, etc. In the present embodiment, the pressure loss coefficients are different in each of the steam pipes L1, L2a, and L2b.

The boiler group 2 includes a plurality of boilers 20 (three in this embodiment), and generates steam to be supplied to the load device group A.
The steam header 6 is connected to a plurality of boilers 20 constituting the boiler group 2 via a steam pipe 11. The downstream side of the steam header 6 is connected to the load device group A via steam pipes L1 and L2.
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 load device group A. 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 a plurality of boilers 20 through a signal line 14. 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 load device group A through the steam header 6.
The load required in the boiler system 1 (required load) is the amount of steam used in the load device group A. The number control device 3 determines the fluctuation of the steam pressure inside the steam header 6 corresponding to the fluctuation of the steam usage 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, if the demand load (steam usage) increases due to an increase in demand of the load device group A, and the steam amount supplied to the steam header 6 is insufficient, the steam pressure inside the steam header 6 decreases. It will be. On the other hand, if the required load (steam consumption) decreases due to a decrease in demand of the load device group A and the amount of steam supplied to the steam header 6 becomes excessive, the steam pressure inside the steam header 6 increases. Become. Therefore, the boiler system 1 can monitor the fluctuation of the required load based on the fluctuation of the vapor pressure measured by the vapor pressure sensor 7. And the boiler system 1 calculates the required evaporation amount which is the evaporation amount required according to the steam usage (required load) of the load apparatus group A based on the steam pressure of the steam header 6, and each boiler 20 Control the amount of combustion. In the boiler system 1 of the present embodiment, a target pressure corresponding to the required load is set, and when the vapor pressure measured by the vapor pressure sensor 7 is lower than the target pressure, the combustion amount of each boiler is increased, When the vapor pressure measured by the pressure sensor 7 is higher than the target pressure, the combustion amount is controlled by reducing the combustion amount of each boiler.

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 difference between the steam pressure in the steam header 6 to be controlled and the target pressure. 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 (20%) as a low combustion position, a medium combustion position (60%) as a base combustion position, and It is constituted by a so-called four-position control boiler 20 that can be combusted at four combustion positions of a high combustion position (100%) as a high combustion position. In this case, for example, when the combustion amount in the fuel state (high combustion state) in the high combustion position of one boiler 20 is 3000 kg / h, the combustion amount in the middle combustion position is 1800 kg / h, and in the low combustion position. The combustion amount is 600 kg / h.

  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 3 positions (combustion stop position, low combustion position, and high combustion position), or 5 positions or more.

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 middle combustion position (medium combustion state). ) Is indicated as “M”, the combustion state at the low combustion position (low combustion state) is indicated as “L”, and the combustion stop state is indicated as “−”.

  As the combustion pattern, a pattern with a smaller combustion amount is selected as the required load becomes smaller, that is, as the vapor pressure detected by the vapor pressure sensor 7 becomes higher than the target pressure. Further, a pattern is selected in which the combustion amount increases as the required load increases, that is, the vapor pressure becomes lower than the target pressure. As shown in FIG. 3, in the present embodiment, the vapor pressure control range is divided into ten vapor pressure zones a to j. 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. Ten combustion patterns are set corresponding to ten 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 positioned at the combustion stop position (−), and the lowest steam pressure is reached. In the band j (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 plurality of 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 unit has the highest priority, and Lowest priority. 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 present embodiment, as shown in FIG. 3, in the case of decreasing from the highest steam pressure zone a toward the lowest steam pressure zone j, in normal control, the boiler with the highest priority (here Then, after the No. 1 boiler is changed from the combustion stop state (−) to the low combustion state (L), the next highest boiler (here, No. 2 boiler) is changed from the combustion stop state (−) to the low combustion state ( L). Then, 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 to the middle combustion state (M) in order. Moreover, after all the boilers 20 are changed to the middle combustion position (M), the boilers having the highest priority are changed to the high combustion position (H) in order.

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 number control device 3 compares the steam pressure signal from the steam pressure sensor 7 with the target pressure, and thereby the required combustion amount of the boiler group 2 corresponding to the required load and the combustion position of each boiler 20 corresponding to the required combustion amount. (Combustion state) is calculated, and a unit number control signal is transmitted to each boiler 20 (local control unit 22 described later). As shown in FIG. 1, the number control device 3 includes a storage unit 5 and a control unit 4.

  The storage unit 5 includes information such as the contents of instructions given to each boiler 20 under the control of the number control device 3 (control unit 4), the combustion state received from each boiler 20, and the combustion patterns of the plurality of boilers 20. Information on setting conditions, information on setting priorities of a plurality of boilers 20, information on setting on changing priority (rotation), and the like.

  The control unit 4 controls the combustion states and priority levels of the three boilers 20 by giving various instructions to each boiler 20 via the signal line 16 and receiving various data from each boiler 20. . When each boiler 20 receives a signal for changing the combustion state from the number control device 3, it controls the boiler 20 according to the instruction.

As shown in FIG. 1, the boiler 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 local control unit 22 changes the combustion state of the boiler 20 according to the required load. Specifically, the local control unit 22 controls the combustion state of the boiler 20 based on the number control signal transmitted from the number control device 3 via the signal line 16.
Further, the local control unit 22 transmits a signal used in the number control device 3 to the number control device 3 via the signal line 16. Examples of the signal used in the number control device 3 include an actual combustion state of the boiler 20 and other data.

ＴＰ：目標圧力
Ｐ：蒸気使用負荷装置の所要圧力
ΔＰ：蒸気使用負荷装置までの圧力損失 As described above, in the boiler system 1, the combustion state of the plurality of boilers 20 is controlled so that the steam pressure inside the steam header 6 becomes the target pressure. In this embodiment, this target pressure setting method is characterized. Have. That is, in the present embodiment, attention is paid to a load device that actually uses steam among the plurality of load devices A1, A2, and A3 (hereinafter, sometimes referred to as “steam use load device”). The target pressure is set so that the pressure of the arrived steam matches the required pressure of the steam load device. Specifically, the target pressure is set in consideration of the pressure (pressure loss) that is lost due to the properties of the steam pipe before reaching the steam use load device to the required pressure of the steam use load device (see equation (1)) ).

TP: Target pressure P: Required pressure of steam load device ΔP: Pressure loss to steam load device

  In this way, by controlling the combustion state of the boiler 20 in accordance with the target pressure TP set by paying attention to the steam load device that actually uses steam, the pressure of the steam reaching the steam load device is kept constant (required pressure) P).

Ｃ：蒸気使用負荷装置に接続する蒸気管の圧力損失係数
Ｖ：蒸気使用負荷装置に接続する蒸気管を流通する蒸気の流量 Here, since the required pressure P can be fixedly determined for each of the load devices A1, A2, and A3, it can be stored in advance in a predetermined table. On the other hand, the pressure loss ΔP is determined by the pressure loss coefficient of the steam pipe and the flow velocity of the steam flowing through the steam pipe. In this respect, the pressure loss coefficient of the steam pipe can be fixedly determined by the material, diameter, extension, etc. of the steam pipe, and can be stored in a predetermined table in advance. For ease of explanation, in this embodiment, the pressure loss coefficient includes a coefficient for calculating the steam flow velocity from the steam flow rate (supply steam amount) in addition to the coefficient determined by the properties of the steam pipe. . As a result, the pressure loss ΔP can be calculated by the following equation (2).

C: Pressure loss coefficient of the steam pipe connected to the steam load device V: Steam flow rate through the steam pipe connected to the steam load device

  Therefore, in this embodiment, the target pressure TP focusing on the steam load device is set by acquiring the flow rate V in the steam pipe through which the steam flows. In the present embodiment, the flow rate V is acquired by any one of the following methods (A) to (C) or a combination of two or more. As a combination of the methods (A) to (C), an average value of the flow rates V acquired by the respective methods may be adopted. A high flow rate V may be adopted, or a weighted average value obtained by applying a predetermined weight to the flow rate V acquired by each method may be adopted.

(A) Acquisition of flow rate V using steam flow meter output signal As shown in FIG. 1, steam flow meters 31 a and 31 b for measuring the flow rate of steam are installed in the steam pipes L 1 and L 2, and the signal line 15 is used. It is electrically connected to the number control device 3. And by setting it as the structure which transmits an output signal with respect to the number control apparatus 3 from the steam flowmeters 31a and 31b via the signal wire | line 15, the flow volume V to a steam use load apparatus is acquired in the number control apparatus 3. Can do.

(B) Acquisition of Flow V Using Load Device Operation Signal As shown in FIG. 1, operation detection switches 32a, 32b, and 32c that detect whether the load devices A1, A2, and A3 are operating / stopped are installed. The number control device 3 is electrically connected via the signal line 16. And by using the structure which transmits an operation signal with respect to the number control apparatus 3 from the operation detection switch 32a, 32b, 32c via the signal wire | line 16, the steam use load apparatus can be specified in the number control apparatus 3. FIG. . Since the steam usage can be fixedly determined for each load device, the steam usage for each load device is stored in advance in a predetermined table, and the steam usage of the steam usage load device specified based on the operation signal is stored. By acquiring the amount, the flow rate V (= steam use amount) to the steam use load device can be obtained in the number control device 3.
If the operation detection switches 32a, 32b, and 32c can also detect the operation rates of the load devices A1, A2, and A3, more accurate steam use can be obtained by multiplying the steam usage during 100% operation by the operation rate. A quantity (flow rate V) can be acquired.
Further, when the same steam pipe L2 is shared like the load devices A2 and A3, when the operation of the load devices A2 and A3 is detected, the steam usage amount of the load device A2 and the steam usage amount of the load device A3 May be acquired as the flow rates V1 and V2, respectively, or a value obtained by adding the steam usage amount of the load device A2 and the steam usage amount of the load device A3 may be acquired as the flow rate V. The method for obtaining the flow rate V when the steam pipe is shared is preferably set in advance according to the branching position of the steam pipe and the difference in the pressure loss coefficient in the steam pipe after branching.

  In addition, as long as operation detection switch 32a, 32b, 32c can detect the heat exchange amount in load apparatus A1, A2, A3, it is good also as a structure which estimates steam usage from heat exchange amount.

(C) Acquisition of Flow V Using Open / Close Signal of Air Supply Valve As shown in FIG. 1, the air supply valves 33a and 33b for controlling the supply of steam from the steam header 6 to the steam pipes L1 and L2 are connected to the signal line 17. Is electrically connected to the number control device 3 via And by setting it as the structure which transmits an opening-and-closing signal with respect to the number control apparatus from the air supply valves 33a and 33b via the signal wire | line 17, the steam pipe which supplies the steam from the steam header 6 in the number control apparatus 3 is used. The type (that is, whether or not the steam header 6 and the steam pipes L1 and L2 are connected) can be specified. Since steam is supplied to the steam pipe whose air supply valve is open, the load device downstream of the open air supply valve becomes the steam use load device. Therefore, the steam usage of the load device (steam usage load device) downstream of the air supply valve identified as being opened by the open / close signal using the steam usage for each load device stored in advance in a predetermined table. By acquiring the flow rate V (= steam use amount) to the steam use load device in the number control device 3 can be obtained.
In addition, when branching from the same steam pipe L2 like the steam pipes L2a and L2b, it is preferable to specify the steam load device using the opening / closing signals of the air supply valves 33c and 33d for controlling the branching. That is, when the air supply valves 33b and 33c are opened, the load device A2 is specified as the steam use load device, and when the air supply valves 33b and 33d are opened, the load device A3 uses the steam. Identified as a load device. Further, when the air supply valves 33b, 33c, and 33d are opened, the load devices A2 and A3 are specified as the steam use load devices.

Heretofore, the method for obtaining the flow rate V for setting the target pressure TP has been described. Next, a functional configuration of the number control device 3 for realizing the acquisition of the flow rate V and the setting of the target pressure TP will be described with reference to FIG.
The control unit 4 of the number control device 3 includes a use device specifying unit 41, a supply amount acquiring unit 42, a pressure loss calculating unit 43, and a target value setting unit 44. In addition, the storage unit 5 of the number control device 3 includes a steam pressure L in the load devices A1, A2, A3 and steam pipes L1, L2a, L2b connecting the steam header 6 to the load devices A1, A2, A3. And a pressure loss coefficient C of at least. In addition, when acquiring the flow volume V by the method of said (B) (C), it is preferable to memorize | store the steam usage-amount of load apparatus A1, A2, A3 in the memory | storage part 5. FIG.

  The use device specifying means 41 specifies a steam use load device that uses steam among the load devices A1, A2, and A3. As an example, the use device specifying means 41 uses the load devices A1, A2 and A3 located downstream of the steam pipes L1 and L2 into which steam flows based on the output signals received from the steam flow meters 31a and 31b. Identifies as a load device. Further, the use device specifying means 41 may specify the steam use load device based on the operation signals from the operation detection switches 32a, 32b, 32c and the open / close signals from the air supply valves 33a, 33b, 33c, 33d. Good.

  The supply amount acquisition means 42 acquires the supply amount (flow rate V) of the steam supplied to the steam use load device via the steam pipes L1, L2a, L2b. The method for obtaining the flow rate V is as described above, and the supply amount obtaining means 42 is based on the output signal received from the steam flow meters 31a and 31b and the steam use amount corresponding to the specified steam use load device. Get V.

  The pressure loss calculating means 43 calculates the pressure loss ΔP accompanying the supply of steam to the steam using load device based on the pressure loss coefficient C and the flow rate V of the steam pipe connecting the steam header 6 to the steam using load device. . Specifically, the pressure loss calculation means 43 calculates the pressure loss ΔP according to the above equation (2).

The target value setting means 44 sets the target pressure TP based on the required pressure P and pressure loss ΔP of the steam load device. That is, the target value setting means 44 sets the target pressure TP according to the above equation (1). A specific example of setting the target pressure TP by the target value setting means 44 will be described later with reference to FIG.
When the target pressure TP is set, the control unit 4 of the number control device 3 controls the combustion state of the plurality of boilers 20 according to the control method described with reference to FIG. Control to be

Next, the storage unit 5 will be described. FIG. 5 is a diagram illustrating an example of information stored in the storage unit 5. As explained so far, in addition to the required pressure for each of the load devices A1, A2, and A3, the storage unit 5 has a pressure loss coefficient for each of the steam pipes L1, L2a, and L2b corresponding to the load devices A1, A2, and A3. At least stored, and the steam usage for each of the load devices A1, A2, A3 is stored as necessary.
In FIG. 5, for easy understanding, the pressure loss when the load devices A1, A2, and A3 are operated at 100% is also stored in the storage unit 5. According to FIG. 5, the pressure of 0.20 MPa is lost until the steam reaches the load device A1 from the steam header 6, and the pressure of 0.16 MPa is lost until the steam reaches the load device A2 from the steam header 6. The pressure of 0.15 MPa is lost until the steam reaches the load device A3 from the header 6.

Next, a specific example of setting the target pressure TP will be described with reference to FIG.
Referring to FIG. 6 (1), when the steam is used in the load device A1, and the steam is not used in the load devices A2 and A3, the load device A1 becomes a steam-use load device. Referring to FIG. 5, since the required pressure P of the load device A1 is 1.50 MPa and the pressure loss ΔP is 0.20 MPa, the target pressure TP is 1.70 MPa (1.50 MPa + 0.20 MPa). As a result, the control unit 4 of the number control device 3 controls the combustion state of the boiler 20 so that the pressure of the steam header 6 becomes 1.70 MPa.
With reference to FIG. 6 (2), when the steam is used in the load device A2, and the steam is not used in the load devices A1 and A3, the load device A2 becomes the steam-use load device. Referring to FIG. 5, since the required pressure P of the load device A1 is 1.51 MPa and the pressure loss ΔP is 0.16 MPa, the target pressure TP is 1.67 MPa (1.51 MPa + 0.16 MPa). As a result, the control unit 4 of the number control device 3 controls the combustion state of the boiler 20 so that the pressure of the steam header 6 becomes 1.67 MPa.

  Thus, in the boiler system 1 of the present embodiment, the target pressure TP is set and the combustion state of the boiler 20 is controlled so that the steam pressure when reaching the load device that actually uses steam is constant. Thereby, in a load apparatus (steam use load apparatus), ideal steam can be used and a user's convenience can be improved. Further, when the load device that lowers the target pressure TP is a steam-use load device, it is not necessary to increase the pressure of the steam header 6 more than necessary, and the combustion of the boiler 20 can be suppressed, and the boiler 20 can be efficiently operated. Can be driven to.

  Next, the setting of the target pressure TP when there are a plurality of steam use load devices will be described. When the values (P + ΔP) calculated in the above (1) are the same in a plurality of steam-use load devices, it is sufficient to set the value as the target pressure TP, while each value (P + ΔP) is sufficient. If they are different, the target pressure TP is set according to any of the following (a) to (d).

(A) A value with the highest P + ΔP is set as the target pressure TP. Referring to FIG. 6 (3), load devices A1 and A3 are steam-use load devices, and load device A1 is calculated by the above equation (1). While the value is 1.70 MPa, the value calculated by the above equation (1) for the load device A3 is 1.65 MPa. In this case, the highest 1.70 MPa is set as the target pressure TP. According to the setting method of (a), a sufficient pressure can be secured for any of the plurality of steam load devices, but the pressure is excessive for a steam load device having a low P + ΔP. End up.

(B) Setting the lowest value of P + ΔP as the target pressure TP Referring to FIG. 6 (3), the values calculated by P + ΔP are the load device A1 (1.70 MPa) and the load device A3 (1.65 MPa). Therefore, the lowest 1.65 MPa is set as the target pressure TP. According to such a setting method (b), combustion of the boiler 20 can be suppressed, but pressure is insufficient for a steam load device having a high P + ΔP.

(C) Setting average value of P + ΔP as target pressure TP Referring to FIG. 6 (3), values calculated by P + ΔP are load device A1 (1.70 MPa) and load device A3 (1.65 MPa). Since the average value is 1.675 MPa, 1.675 MPa is set as the target pressure TP. According to such a setting method (c), excessive pressure and insufficient pressure can be reduced. As the average value, a weighted weighted average value may be adopted. In addition to the average value, various values such as mode (mode), median (median), and standard deviation may be adopted. It is good.

(D) Setting P + ΔP of a load device having a high priority as a target pressure TP A priority is set in advance for each load device, and a value calculated by P + ΔP of a steam load device having the highest priority is set as a target pressure. Set as TP. The priority order may be arbitrarily set. For example, a load device with a large amount of steam used may be set to have a high priority order, and the priority order may be set according to the purpose of use of steam. In addition, when the pressure can be adjusted by a pressure reducing valve or the like, the priority order may be set according to the presence or absence of the pressure reducing valve or ease of installation.

  Although the setting methods (a) to (d) have been described above, the methods (a) to (d) may be applied in combination. At this time, as a condition for applying in combination, a deviation amount of a value calculated by P + ΔP in a plurality of steam use load devices may be used. As an example, when the deviation of the value calculated by P + ΔP is less than a predetermined value, the target pressure TP is set by the setting method (minimum value) of (b), and when it is above the predetermined value, the setting method of (a) The target pressure TP is set according to (maximum value). According to such setting, when the deviation is small, the setting method (minimum value) of (b) is adopted, so that pressure shortage can be suppressed. On the other hand, when the deviation is large, the setting method (maximum value) of (a) is adopted, so that the excess pressure becomes large, but it is possible to cope with the excess pressure by adjusting the pressure with a pressure reducing valve or the like. it can.

Next, with reference to FIG. 7, operation | movement of the boiler system 1 of this embodiment is demonstrated.
First, in step ST1, the control unit 4 (use device specifying means 41) specifies a load device using steam, that is, a steam use load device, based on a predetermined signal received via the signal line.

  Subsequently, in step ST1, the control unit 4 (supply amount acquisition means 42) is based on the output signals received from the identified steam flow meters 31a and 31b and the steam usage stored in association with the identified steam usage load device. Then, the flow rate V of the steam flowing through the steam pipe that supplies the steam to the steam load device is acquired.

  Subsequently, in step ST3, the control unit 4 (pressure loss calculating means 43) calculates the pressure loss ΔP from the pressure loss coefficient C and the flow rate V of the steam pipe through which the steam flows according to the above equation (2).

  Subsequently, in step ST4, the control unit 4 (target value setting means 44) adds the pressure loss ΔP to the required pressure P of the steam load device according to the above equation (1). Subsequently, in step ST5, the control unit 4 (target value setting means 44) sets the target pressure TP based on the addition result. At this time, when there is one steam use load device, the addition result is the target pressure TP, and when there are two or more steam use load devices, the target is determined by the setting methods (a) to (d) above. Set the pressure TP.

  Subsequently, in step ST <b> 4, the control unit 4 controls the combustion state of the plurality of boilers 20 based on the set target pressure TP and adjusts the pressure of the steam header 6.

  The embodiment of the boiler system 1 of the present invention has been described above. According to such a boiler system 1, the steam header 6 stores steam having a pressure corresponding to the required pressure P of the steam using load device that uses steam. In particular, since the steam at the target pressure TP obtained by adding the pressure loss ΔP to the steam load device to the required pressure P is stored in the steam header 6, the steam supplied from the steam header 6 is stored in the steam load device. Even if the pressure drops due to the pressure loss until it reaches, it reaches the required pressure P of the steam load device when it reaches the steam load device. Thereby, the pressure in the steam load device that uses steam can be controlled to be constant. As a result, the pressure of the steam header 6 can be suppressed and the boiler can be controlled efficiently compared to the conventional method of setting the target pressure in consideration of a safety factor higher than necessary.

  As mentioned above, although one preferable embodiment of the boiler system 1 of this invention was described, this invention is not restrict | limited to embodiment mentioned above and can change suitably.

  For example, in this embodiment, although the some boiler 20 was comprised by the step value control boiler, it is not restricted to this. That is, you may comprise a some boiler with the proportional control boiler which can burn by changing a load factor continuously.

  DESCRIPTION OF SYMBOLS 1 ... Boiler system, 2 ... Boiler group, 3 ... Number control apparatus, 4 ... Control part, 41 ... Used apparatus identification means, 42 ... Supply amount acquisition means, 43 ... Pressure loss calculation means, 44 ... Target value setting means, A ... load device group, L1, L2 ... steam pipe, TP ... target pressure, P ... required pressure, ΔP ... pressure loss, V ... flow rate (amount of supplied steam)

Claims (8)

A plurality of boilers combustible at a staged combustion position, a steam header for storing steam generated from the plurality of boilers, and a control for controlling the pressure of the steam stored in the steam header to a target pressure value A boiler system that supplies steam to the plurality of load devices from the steam header via supply paths having different pressure losses.
The control device includes:
Storage means for storing a required pressure of steam used for each of the plurality of load devices;
A use device specifying means for specifying a steam use load device using steam among the plurality of load devices;
Supply amount acquisition means for acquiring the amount of steam supplied to the steam load device;
Pressure loss calculating means for calculating a pressure loss associated with the supply of steam to the steam using load device based on a pressure loss coefficient of the supply path corresponding to the steam using load device and the amount of supplied steam;
Target value setting means for setting the target pressure value based on the required pressure and the pressure loss corresponding to the steam load device;
Boiler system equipped with. A flow meter for measuring the flow rate of the steam flowing through the supply path;
The supply amount acquisition means acquires the supply steam amount based on the flow rate measured by the flow meter.
The boiler system according to claim 1. The storage means stores a steam usage amount for each of the plurality of load devices,
The supply amount acquisition means acquires the supply steam amount based on the steam use amount corresponding to the steam use load device.
The boiler system according to claim 1. The use device specifying means specifies the steam use load device by receiving an operation signal from the load device.
The boiler system according to any one of claims 1 to 3. An air supply valve that connects or disconnects the steam header and the supply path;
The use device specifying means specifies a load device to which steam is supplied via the supply path connected by the air supply valve as the steam use load device.
The boiler system according to any one of claims 1 to 3. When there are a plurality of steam use load devices using steam, the target value setting means calculates the target pressure by adding the value of the steam use load device having the largest sum of the required pressure and the pressure loss. Set as value,
The boiler system according to any one of claims 1 to 5. When there are a plurality of steam-use load devices that use steam, the target value setting means calculates the target pressure by adding the value of the steam-use load device that has the smallest sum of the required pressure and the pressure loss. Set as value,
The boiler system according to any one of claims 1 to 5. When there are a plurality of steam use load devices using steam, the target value setting means calculates an average value in the plurality of steam use load devices of an addition value obtained by adding the required pressure and the pressure loss. Set as pressure value,
The boiler system according to any one of claims 1 to 5.

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