JP2005043001A - Quantity controller in multiple unit installation system for boilers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a frequency of changing a burning capacity of a boiler, and to carry out efficient operation of the boiler in a multiple unit installation system for boilers. <P>SOLUTION: In the multiple unit installation system for boilers, a plurality of boilers 1 is installed comprising basic units and auxiliary units, and steam generated by each boiler 1 is collected and then supplied to a steam using part 2. It is provided with the quantity controller setting a plurality of pressure divisions by dividing a pressure control range of a steam pressure on the basis of a combustion control pattern, determining combustion states in individual boilers by detecting a corresponding pressure division of a steam pressure value in a steam collecting part 4, and carrying out quantity control of carrying out combustion in a necessary number of boilers. Quantity control of using only boilers of the basic units, and quantity control of using all controllable boilers are carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a number control device in a boiler multi-can installation system.

  2. Description of the Related Art A boiler multi-can installation system that installs a plurality of boilers and adjusts the number of boiler combustions according to the load is known. In the case of a multi-can installation system for steam boilers, the amount of steam generated is adjusted by controlling the combustion amount (number) of the boilers using a unit control device. The number of boilers installed is a few cans as spare cans in addition to the number of boilers required for steam supply so that the steam supply amount will not be insufficient even if some boilers become unusable due to repairs or malfunctions. An extra boiler is installed, and the steam generated in each boiler is collected in a steam header and supplied to the steam using section. The classification of basic cans and spare cans is a category when considering the number of boilers installed. There is no distinction between basic cans and spare cans in the actual installed boilers, and the number of boilers is controlled. This is done throughout the boiler.

  The number control device performs number control based on the steam pressure value detected by the pressure detection device provided in the steam header. In the multi-unit control system, the pressure control range of steam pressure is divided into multiple pressure categories, the combustion amount of the boiler is determined for each pressure category, and which pressure category the steam pressure value detected by the steam header corresponds to The amount of boiler combustion is calculated by the above, and the required number of boilers are burned. The steam pressure value falls within the control pressure range by decreasing the number of boiler combustions as the steam pressure value shifts to the high pressure side pressure category, and increasing the number of boiler combustions as the steam pressure value shifts to the low pressure side pressure category. Control to be kept at.

  9 and 10 explain the conventional number control. FIG. 9 shows that five boilers consisting of three basic cans and two spare cans are installed, and the pressure control range is 0.70 MPa to 0.78 MPa. FIG. 10 is an explanatory diagram showing changes in the steam pressure value and the number of boiler combustions. If 5 boilers that are ON-OFF controlled are installed and the pressure control range is 0.70MPa to 0.78MPa, the steam pressure value is less than 0.70MPa, which is the lower limit of the pressure control range. Except when combusting and when stopping all boilers to be controlled exceeding the upper limit of the pressure control range, 0.78 MPa, the combustion control pattern is `` ON, OFF, OFF, OFF, OFF '', `` ON, ON , OFF, OFF, OFF ”,“ ON, ON, ON, OFF, OFF ”,“ ON, ON, ON, ON, OFF ”. In the pressure control range, the number of combustion control patterns is equally divided by 4. Therefore, in the pressure control range, a pressure section is provided for each 0.02 MPa, and the number of boiler combustions is determined for each pressure section. In other words, when the steam pressure value is less than 0.70MPa, 5 boilers are burned. When the steam pressure value is within the range of 0.70MPa to 0.72MPa, 4 boilers are burned, and the steam pressure value is 0.72. When it is within the range of MPa to 0.74 MPa, 3 boilers are burned. When the steam pressure value is within the range of 0.74 MPa to 0.76 MPa, 2 boilers are burned, and the steam pressure value is from 0.76 MPa. If it is within the range of 0.78MPa, one boiler will be burned, and if the steam pressure value exceeds 0.78MPa, the number of burners will be set to 0.

  The steam pressure value in FIG. 10 starts from a state below 0.70 MPa, which is the lower limit of the pressure control range, and in this case, all five boilers are combusted. If the steam pressure rises and enters the pressure range from 0.70 MPa to 0.72 MPa, the number of combusted units will be four, and if it further rises and falls within the range of 0.72 MPa to 0.74 MPa, the number of combusted units will be three. Every time the steam pressure value rises and moves to the high pressure side pressure section, control is performed to reduce the number of combustion units. Conversely, if the steam pressure value decreases, the boiler pressure Control to increase the number of combustion.

  In this case, the number of boilers is controlled using all the installed boilers, so when the steam pressure is low, such as at the start of work, to burn all the boilers that are more than the number of basic cans. The time required for increasing the steam pressure can be shortened. However, if the number of boilers that control the number of units increases, the pressure range of each pressure category defined within the control pressure range decreases, and the number of combustion units changes even with slight pressure fluctuations. Will be done. In addition, there is a time difference between the output of the change in the number of burned units and the actual increase or decrease in the amount of steam generated. Then, there is a possibility that the oscillation repeatedly causes the output to be greatly changed in the opposite direction. In such a case, there is a problem that the stability of the steam pressure is deteriorated and the life is shortened because the number of start / stop times of the device is increased.

Therefore, when the amount of steam used is small, it has been considered to reduce the number of boilers that perform unit control, re-set the pressure category widely, and perform unit control based on the reset pressure category. However, if the number of boilers that perform unit control is reduced, the possibility that the steam pressure value will fall below the lower limit of the pressure control range increases due to a shortage of steam supply, and the reduced steam pressure does not recover to the pressure control range. Fear will arise.
JP 2001-132902 A

  The problem to be solved by the present invention is to reduce the frequency of changing the amount of combustion of the boiler in a boiler multi-can installation system and to operate the boiler efficiently.

  Multiple boilers consisting of basic cans and spare cans are installed, and the steam generated in each boiler is collected and then supplied to the steam use section. The steam pressure within the pressure control range is set to the combustion control pattern. By dividing based on this, multiple pressure categories are set, and by detecting which pressure category corresponds to the steam pressure value in the steam collecting part, the combustion state in each boiler is determined, and the required number of boilers are burned In a boiler multi-can installation system provided with a unit control device for controlling the number of units, the unit control using only the boiler for the basic can and the unit control using the entire controllable boiler are performed.

  By implementing the present invention, there is an advantage that the frequency of changing the combustion amount of the boiler can be reduced, and further, the operation efficiency of the boiler can be improved by eliminating unnecessary combustion of the boiler.

  FIG. 1 is a block diagram showing the overall configuration of a boiler multi-can installation system in an embodiment of the present invention device, and FIG. 2 is an explanatory diagram showing the relationship between the steam pressure value of the unit control A and the boiler combustion control pattern in the embodiment. 3 is an explanatory diagram showing the relationship between the steam pressure value of the unit control B and the boiler combustion control pattern in the embodiment, and FIG. 4 is an explanatory diagram showing the relationship between the steam pressure value of the unit control C and the boiler combustion control pattern in the embodiment. FIG. 5 is an explanatory diagram of the steam pressure change and boiler combustion unit control status in the first embodiment, FIG. 6 is an explanatory diagram of the steam pressure change and boiler combustion unit control status in the second embodiment, and FIG. FIG. 8 is an explanatory diagram of the steam pressure change state and the boiler combustion unit control status in the embodiment, and FIG. 8 is an explanatory diagram of the unit control switching status in the fourth embodiment.

  In this embodiment, five boilers 1 that perform combustion control by ON-OFF are installed, and a steam header 4 that collects steam generated in each boiler is provided. The generated steam is collected in the steam header 4 through the steam pipe 5 that connects each boiler 1 and the steam header 4 and then sent to the steam using unit 2. The steam header 4 includes a pressure detector that detects the steam pressure. 6 is provided. Each boiler is provided with an operation control device 7, and the operation control device 7 receives a combustion request signal from the number control device 3 and performs combustion control of the boiler. The pressure control range is 0.70MPa to 0.78MPa, and the unit control device 3 keeps the steam pressure value detected by the pressure detector 6 of the steam header 4 within the pressure control range of 0.70MPa to 0.78MPa. Control the number of combustion. Here, five boilers are installed, but only three boilers (basic cans) are required during normal operation, and the remaining two boilers can supply steam due to a failure in the boiler. It corresponds to a spare can installed extra so that the steam supply amount will not be insufficient even when it becomes impossible.

  First, the first embodiment will be described. In the case of the first embodiment, the number control device 3 includes a number control A in which the pressure control range is divided by the number of combustion control patterns that can be used by using the entire controllable boiler, and a basic unit. The number control B is set in which the pressure control range is divided by the number of combustion control patterns using only the boiler for the can and the pressure classification is provided. If the steam pressure value detected by the pressure detector 6 is lower than the lower limit of the pressure control range, the number control device 3 executes the number control by the number control A, and the detected steam pressure value is within the pressure control range. If it is higher than the lower limit, the number control by the number control B is executed.

  In the case of unit control A, the pressure control range is 0.70MPa to 0.78MPa, so the steam pressure value does not reach the lower limit of 0.70MPa which is the lower limit of the pressure control range, Except when stopping all boilers to be controlled exceeding the upper limit of 0.78 MPa, the combustion control pattern is `` ON, OFF, OFF, OFF, OFF '', `` ON, ON, OFF, OFF, OFF '', `` ON, ON, ON, OFF, OFF ”and“ ON, ON, ON, ON, OFF ”. In the pressure control range, the number of combustion control patterns is equally divided by 4. Therefore, in the pressure control range, a pressure section is provided for each 0.02 MPa, and the number of boiler combustions is determined for each pressure section. In other words, when the steam pressure value is less than 0.70 MPa, 5 boilers are burned, and when the steam pressure value is in the pressure category of 0.70 MPa to 0.72 MPa, 4 boilers are burned, and the steam pressure value is 0.72 When in the pressure range from MPa to 0.74 MPa, 3 boilers are combusted. When the steam pressure value is in the pressure range from 0.74 MPa to 0.76 MPa, 2 boilers are combusted, and the steam pressure value is from 0.76 MPa. The number of combustion units is determined so that one boiler is burned when the pressure classification is 0.78 MPa, and the number of boilers burned is zero when the steam pressure exceeds 0.78 MPa.

  Since the unit control B is for controlling the number of units within the pressure control range with only three basic cans, each pressure classification becomes large. If the steam pressure value is less than the lower limit of 0.70 MPa, which is the lower limit of the pressure control range, all boilers for the basic can are combusted, and if the upper limit of the pressure control range is 0.78 MPa, all boilers for the basic can are stopped. There are two combustion control patterns excluding the case of “ON, OFF, OFF” and “ON, ON, OFF”. In the pressure control range, the number of combustion control patterns is equally divided by 2. Therefore, in the pressure control range, a pressure section is provided for each 0.04 MPa, and the number of boiler combustions is determined for each pressure section. In other words, when the steam pressure value is less than 0.70MPa, 3 boilers are burned, and when the steam pressure value is in the pressure category from 0.70MPa to 0.74MPa, 2 boilers are burned, and the steam pressure value is 0.74 The number of combustion units is determined so that one boiler is burned when the pressure range is from MPa to 0.78 MPa, and the number of boilers burned is zero when the steam pressure exceeds 0.78 MPa.

  FIG. 5 showing the first embodiment starts from a state in which the steam pressure value is lower than 0.70 MPa. Therefore, the number control A is initially executed. In the number control A, the steam pressure value is lower than 0.70 MPa. In this case, since the number of combustion is five, the number control device 3 instructs the five boilers to perform combustion. When the steam pressure value increases and becomes higher than 0.70 MPa, which is the lower limit value of the pressure control range, the unit control device 3 switches the unit control from A to B. In the case of unit control B, since the combustion amount in the pressure category of the steam pressure value from 0.70 MPa to 0.74 MPa is two units, the unit control device 3 instructs the combustion to only two boilers, and the other boilers combust To stop. When the steam pressure further rises and the steam pressure value enters the pressure range from 0.74 MPa to 0.78 MPa, the combustion amount in the unit control B is one, so the unit control device 3 burns only one boiler 1. And After that, when the steam pressure falls and the steam pressure value enters the pressure range of 0.70MPa to 0.74MPa, the basic can is used when the steam pressure value is within the pressure control range so that the number of boilers burned is two. Unit control is performed by the number of minutes.

  When the steam pressure value becomes lower than the lower limit value of the pressure control range, the unit control device 3 switches the unit control from B to A. In the case of the number control A, since the number of combustion when the steam pressure value is less than 0.70 MPa is five, the number control device 3 instructs the combustion to all five boilers and burns in all the boilers. Similarly, every time the steam pressure value passes the lower limit value of the pressure control range, the number control pattern is changed. When the steam pressure value is within the pressure control range, the number control B with a wide pressure category and a small combustion amount is executed to reduce the combustion amount of the boiler and prevent frequent changes in the combustion amount. When the value is lower than the pressure control range, the steam pressure value is recovered in a short time by executing the unit control A with a large combustion amount.

  Next, a second embodiment will be described. Also in the second embodiment, the number control A and the number control B described in the first embodiment are performed. In the second embodiment, if it is detected that the detected steam pressure value is lower than the lower limit of the pressure control range, the number control by the number control A is executed, and the detected steam pressure value is within the pressure control range. If it is detected that it is higher than the lower limit by a predetermined width (for example, 30% of the pressure control range) or more, the number control by the number control B is executed.

  In FIG. 6, since it starts from a state lower than 0.70 MPa, the number control A is initially executed. In the number control A, the combustion amount is 5 when the steam pressure value is lower than 0.70 MPa. 3 instructs combustion to five boilers. Even if the steam pressure value rises and becomes higher than the lower limit of the pressure control range, unit control A is continued until the steam pressure value increases by 30% (0.024 MPa) of the pressure control range, and the steam pressure value becomes 0.70. Since the number of combustion in the pressure section from MPa to 0.72 MPa is four, the unit control device 3 instructs the four boilers to perform combustion, and one boiler that is excluded from the combustion target stops combustion. When the steam pressure rises and the steam pressure value enters the pressure range from 0.72 MPa to 0.74 MPa, the number of combustions in the unit control A is 3, so the unit controller 3 sets the number of combustion units in the boiler 1 to 3 units. To do.

  When the steam pressure value further rises and rises from the lower limit of the pressure control range to 30% of the pressure control range, that is, 0.724 MPa, the unit control device 3 switches the unit control from A to B. In the case of the number control B, since the combustion amount in the pressure section from 0.70 MPa to 0.74 MPa is two, the number control device 3 sets the number of combustion of the boiler to two. Thereafter, as in the first embodiment, the unit control B is executed when the steam pressure value is within the pressure control range, and the unit control A is executed when the steam pressure value becomes lower than the lower limit of the pressure control range. The change in the number control pattern from A to B is made after a predetermined width or more has been made higher than the lower limit of the pressure control range, and the pressure value for changing the pressure value from A to B is changed from B to A. Because it is higher than the value, unnecessary increase in combustion amount due to delaying the increase in boiler combustion amount can be reduced, and when the combustion amount is increased, the steam pressure value rises to half of the pressure control range. The time to do can be shortened.

  Next, a third embodiment will be described. In the third embodiment, the unit control device 3 controls the number of units based on only the number of basic cans within the pressure control range and controls the number of units based only on the basic cans. In a pressure range lower than the lower limit of the pressure control range, A unit number control C for setting the pressure classification by the spare cans and controlling the number of units including the spare cans is determined.

  In the case of the unit control C, the unit control within the pressure control range is performed by only three basic cans. Therefore, the pressure control range is the same as the unit control B, and the pressure classification for the spare can is the pressure control range. The lower pressure region is set with the same pressure range as the pressure section of the pressure control range. In other words, the unit control C is obtained by adding two pressure categories to the unit control B downward from the lower limit of the pressure control range, and when the steam pressure value is less than 0.62 MPa, which is the lower limit of the added pressure category. If 5 boilers are burned and the steam pressure value is in the pressure range from 0.62 MPa to 0.66 MPa, then 4 boilers are burned. If the steam pressure value is in the pressure range from 0.66 MPa to 0.70 MPa, 3 units are burned. If the steam pressure value is in the pressure category from 0.70MPa to 0.74MPa, then two boilers will be burned. If the steam pressure value is in the pressure category from 0.74MPa to 0.78MPa, one boiler will be burned If the steam pressure value exceeds 0.78MPa, the number of combustion is determined so that the number of boilers burned is zero.

FIG. 7, which is the third embodiment, starts from a pressure section with a steam pressure value of 0.66 MPa to 0.70 MPa. In unit control C, the combustion amount in the pressure section with a steam pressure value of 0.66 MPa to 0.70 MPa is three. Therefore, the unit control device 3 instructs the three boilers to perform combustion, and the other boilers stop combustion. When the steam pressure value rises and enters the pressure range from 0.70 MPa to 0.74 MPa, the number of combustions in the unit control C is two, so the unit control device 3 sets the number of combustion units in the boiler to two.
After that, each time the steam pressure value changes and the pressure section is moved, the number control is performed to change the number of combustion. In the unit control C, since the range of each pressure category is wide, by executing the unit control by the unit control C, the number of boiler combustions when the steam pressure value is within the pressure control range is reduced, and in all regions It is possible to prevent frequent changes in the number of burned units.

  Next, a fourth embodiment will be described. In the case of the fourth embodiment, the number control device 3 is set with the number control A, the number control B, and the number control C, and the number control is combined with the number control A and the number control B. The number control by C is selectively switched according to the magnitude of load fluctuation and the time zone.

  FIG. 8 shows the selection switching state of the unit control pattern in the multi-can installation system that supplies steam to the steam using part that has the time to use steam in a batch type and the time to use steam continuously. In the figure, the first and second periods are batch-type steam use periods, and the middle period is a continuous steam use period. In the case of the batch type steam use period, a large amount of steam may be used in a short time, and the steam pressure value may be greatly reduced. If the steam pressure drops greatly, it is necessary to recover the steam pressure as soon as possible. Therefore, the magnitude of the load fluctuation is detected, and if the load fluctuation is detected, the unit control A and The number control combining the number control B is executed. In the combination control of the unit control A and the unit control B, the unit control A that can recover the steam pressure in a short time, and the unit with a wide pressure category and a small combustion amount when the steam pressure is within the pressure control range By executing the control B, the steam pressure can be recovered in a short time, and frequent changes in the number of combustion can be prevented. When it is detected that the load fluctuation is small, the number control by the number control C is performed. In the case of the continuous steam use period, since the steam is not used rapidly as in the batch-type steam use period, the possibility that the steam pressure is greatly reduced is reduced. Therefore, by executing the unit control C, the number of combustion of the boiler can be reduced and the change frequency of the number of combustion can be further reduced. Whether it is the batch steam use period or the continuous steam use period can be determined by detecting the magnitude of the load fluctuation, and if the time zone is known in advance, a timer reservation is made. It may be switched by a timer.

  Since the unit control B and the unit control C are the same unit control within the pressure control range, the unit control C is set instead of the unit control B in each embodiment. The number control by the number control C may be performed. In the embodiment, the boiler is controlled on and off, and the combustion amount is controlled by the number of combustion units. However, the number of units is controlled by using a boiler that controls combustion at three positions: high combustion, low combustion, and stop. The same applies when performing the above. If each boiler performs stepwise combustion control, the control of the combustion amount is adjusted not only by the number of combustion units but also by the combustion amount in each boiler, but the unit number control method is the same as in the above embodiment. is there.

The block diagram which shows the whole structure of the boiler multi-can installation system in the Example of this invention apparatus. Explanatory drawing of the steam pressure value and combustion control pattern of unit control A in an Example Explanatory drawing of the steam pressure value and combustion control pattern of unit control B in an Example Explanatory drawing of the steam pressure value and combustion control pattern of unit control C in an Example Explanatory diagram of steam pressure change and boiler combustion unit control status in the first embodiment Explanatory diagram of steam pressure change and boiler combustion unit control status in the second embodiment Explanatory diagram of steam pressure change and boiler combustion unit control status in the third embodiment Explanatory drawing of the number control pattern switching situation in the fourth embodiment Explanatory drawing of steam pressure value and combustion control pattern in conventional example Explanatory drawing of steam pressure change and boiler combustion unit control status in conventional example

Explanation of symbols

1 boiler
2 Steam use part
3 Number control device
4 Steam header
5 Steam piping
6 Pressure detector
7 Operation control device

Claims (6)

  Multiple boilers consisting of basic cans and spare cans are installed, and the steam generated in each boiler is collected and then supplied to the steam use section. The steam pressure within the pressure control range is set to the combustion control pattern. By dividing based on this, multiple pressure categories are set, and by detecting which pressure category corresponds to the steam pressure value in the steam collecting part, the combustion state in each boiler is determined, and the required number of boilers are burned In a boiler multi-can installation system equipped with a unit control device for controlling the number of units, a boiler that performs unit control using only the boiler for the basic can and unit control using the entire controllable boiler Unit control system for multi-can installation system.   In the number control apparatus in the boiler multi-can installation system according to claim 1, the number control A and the number control A provided by dividing the pressure control range based on the number of combustion control patterns using the entire controllable boiler Based on the number of combustion control patterns using only the boiler for the basic can, the number control B is set by dividing the pressure control range and the pressure classification is set, and the detected steam pressure value is a predetermined value. If the pressure is lower than the pressure P1, the number control by the number control A is executed, and if the detected steam pressure value is higher than the predetermined pressure P2, the number control by the number control B is executed. Number control device in the installation system.   3. The boiler multi-can installation system according to claim 2, wherein the pressure P2 for performing the unit control B is larger than the pressure P1 for performing the unit control A. Unit control device in   The number control device in the boiler multiple can installation system according to claim 1, wherein the pressure control range is divided based on the number of combustion control patterns using only the boiler for the basic can, and the pressure control range is provided. In the lower pressure region, a pressure section for the preliminary can is provided, and in the pressure region higher than the lower limit of the pressure control range, the combustion amount is controlled only by the boiler for the basic can, and the pressure lower than the lower limit of the pressure control range. A unit control device for a boiler multi-can installation system characterized in that in the area, unit control is performed to control the combustion amount in the entire controllable boiler including the spare can.   In the number control device in the boiler multi-can installation system according to claim 1, the number control A in which the pressure control range is divided and the pressure division is provided based on the number of combustion control patterns using the entire controllable boiler, Unit control B with pressure division divided into the pressure control range based on the number of combustion control patterns using only the boiler for the basic can, Pressure based on the number of combustion control patterns using only the boiler for the basic can The control range is divided and the pressure division is provided. In the pressure region lower than the pressure control range, the unit control C is set with the pressure division for the spare can, and the unit control A and the unit control B are combined. A number control device in a boiler multi-can installation system, wherein the number control and the number control by the number control C are selectively switched.   In the number control apparatus in the boiler multi-can installation system according to claim 1, the number control A and the number control A provided by dividing the pressure control range based on the number of combustion control patterns using the entire controllable boiler The number control C is set by dividing the pressure control range based on the number of combustion control patterns using only the boiler for the basic can, and providing the pressure division even in the pressure region lower than the pressure control range. A number control device in a boiler multi-can installation system characterized in that the number control by combining the number control A and the number control C and the number control by the number control C are selectively switched.

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