JP2003302003A - Number control device for multiple can installed boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent steam pressure in a multiple can installed boiler from being out of a proper range during the change of operating priority. <P>SOLUTION: The multiple can installed boiler is provided with a in plurality of boilers, and the operating priority is set for every boiler. The required number of boilers are used according to higher operating priority for combustion, depending on the required amount of stream and the remaining boilers are controlled to be stopped, whereby the amount of steam to be generated in all boilers is controlled. The operating priority is periodically changed. Combustion starting boilers which are stopped but changed for combustion by advancing the priority higher during the change of the operating priority is separated from the other boilers, and the change of the operating priority of the combustion starting boilers is performed a time T1 preceding the change of the operating priority of the other boilers. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the number of boilers installed in multiple cans in which the required number of boilers are combusted in the descending order of operation priority in accordance with the required amount of steam, and the operation priority is changed periodically. The present invention relates to a control device.

[0002]

2. Description of the Related Art A plurality of small boilers are installed in advance, and multiple cans are installed to burn a required number of boilers in accordance with the required amount of steam. In a multi-can installation system, the required steam amount is calculated by measuring the steam pressure value at the steam collecting portion, and the required number of boilers determined from the steam pressure value are burned. When the steam pressure value decreases and the required steam amount increases, the boilers start combustion in order from the boiler with the highest operation priority, and the steam pressure value increases and the steam supply amount decreases. Then, the combustion is stopped in order from the boiler having the lowest operation priority. In this case, the boiler with the higher operation priority has more chances to burn, and if the combustion concentrates on a specific boiler, the life of the entire device will be shortened.Therefore, by changing the operation priority regularly, the combustion time Is prevented from being biased.

When the operation priority is changed, combustion is stopped by lowering the rank of the boiler that was burning, and combustion is started instead by raising the rank of the boiler that has stopped burning. Sometimes. In this case, the boiler that stops combustion immediately stops generating steam, but before the boiler that has started combustion generates steam, it takes time to prepare for combustion such as prepurge and heating of the boiler. Therefore, it is not possible to start the steam supply immediately after receiving the command to start combustion. Therefore, when the boiler that burns is changed by changing the operation priority, the steam supply amount decreases until the boiler that starts new combustion starts steam supply, so there is a problem that the steam pressure drops during that time. there were.

Therefore, until the boiler, which has been newly started to burn due to the change of the operation priority order, starts to supply steam, the combustion stop of the boiler which stops the combustion due to the lowering of the operation priority order is delayed. By doing so, it was possible to prevent the steam pressure from dropping when changing the operating priority. Even after the combustion has been stopped, if the boiler that has started a new operation starts steam supply until the boiler starts to be supplied, the steam supply amount will not be insufficient due to the order change.

However, with a boiler that has newly started combustion,
Even if only the boilers that continue burning after the ranking change are burning, and the boilers that have newly started burning are not generating steam, the steam used at that time is generated by one boiler. If it is less than the amount, the vapor pressure will increase. Therefore, in this case, if the boiler, which newly starts combustion, continues combustion in the boiler until it reaches a predetermined combustion state, the steam pressure increases more than necessary.

[0006]

The problem to be solved by the present invention is to prevent the steam pressure from deviating from an appropriate range when changing the operation priority order in a multi-can installed boiler.

[0007]

According to a first aspect of the present invention, a plurality of boilers are installed, an operation priority order is set for each boiler, and the operation priority order is set according to a required steam amount. The number of boilers is combusted, and the remaining boilers are stopped to control the amount of steam generated in the entire boiler, and the operation priority is regularly changed. In the above, when the operation priority is changed, it is divided into a combustion start boiler that changes from stop to combustion by moving up to a higher rank, and another boiler other than that. It is characterized in that the operation priority order is changed by a preceding time T1 before the change of the operation priority order.

According to the second aspect of the present invention, a plurality of boilers are installed, operation priorities are set for each boiler, and the required number of boilers are burned in the descending order of operation priority in accordance with the required steam amount. And the remaining boilers are stopped to control the amount of steam generated in the entire boiler.
In a multi-can installation boiler whose operation priority is changed regularly, when the operation priority is changed, the combustion stop boiler that will be changed from combustion to stop due to the lowering of the operation priority, and other boilers other than that. The combustion priority boiler is characterized in that the operation priority order is changed with a delay time T2 delayed from the operation priority order change of other boilers.

According to the invention described in claim 1, the boiler which starts combustion by changing the operation priority is
Since the combustion preparation is started before the operation priority is changed, the steam can be supplied when the operation priority is changed, and the operation priority can be changed without lowering the steam pressure. According to the invention as set forth in claim 2, the boiler, which will stop the combustion by changing the operation priority, delays the order change by the delay time T2 from the time of changing the operation priority, and during that time, Since the ranking is continued and combustion is performed, it is possible to prevent a decrease in the steam supply amount immediately after the change of the operation priority order, and it is possible to change the operation priority order without the steam pressure decreasing.

[0010]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flow sheet showing an installation situation of a boiler for carrying out the present invention, FIG. 2 is a time chart showing an operation priority order and a combustion situation of each boiler in one embodiment, and FIG. 3 is each boiler in another embodiment. 3 is a time chart showing the operation priority order and the combustion status of FIG. In this embodiment, 3
The boilers 1 are installed in parallel, and each boiler is named Boiler A, Boiler B, Boiler C. The steam piping from each boiler is connected to the steam header 4, and the pressure detection device 3 is provided in the steam header 4. The operation command to each boiler 1 is the control device 2 for the number of units connected to each boiler.
The unit number control device 2 is also connected to the pressure detection device 3.

Each boiler 1 is provided with a boiler operation controller 5, and the boiler operation controller 5 is a unit number controller 2
The boiler operation control device 5 controls the operation of each device of the boiler 1 based on a command output from the number-of-units control device 2 to the boiler operation control device 5 in order to control the operation of the boiler. . When starting the combustion of the boiler,
The boiler operation control device 5 first sends only air into the combustion chamber to perform a pre-purge for ventilating the combustion chamber, then performs an ignition process to start combustion, heats can water in the boiler to generate steam. I do. When the combustion of the boiler is stopped, the boiler operation control device 5 stops the supply of fuel to stop the combustion, and then performs the post-purge for ventilating the combustion chamber to stop the operation.

The number-of-units control device 2 determines the required amount of steam based on the steam pressure value detected by the pressure detection device 3, and outputs a combustion command to the required number of boilers. When the steam pressure value decreases and the required steam amount increases, the boilers start combustion in order from the boiler with the highest operation priority, and the steam pressure value increases and the required steam amount decreases. Then, by stopping the combustion in order from the boiler having the lowest operation priority, the number of units is controlled according to the required steam amount. The operation priority is changed every 24 hours, the integrated value of the combustion time is calculated for each boiler, and the operation priority is changed so that the combustion time is shorter, the operation priority is higher.

Before changing the operation priority of the boiler, the unit number control device 2 determines whether or not there is a combustion start boiler which is a boiler that changes from the stopped state to the combustion by raising the operation priority to a higher level. Check and distinguish the combustion start boiler from other boilers that are other boilers. When there is a combustion start boiler, when changing the operation priority order of the boiler, the combustion start boiler is set to change the order prior to the change of the order of other boilers by the preceding time T1. The value of the leading time T1 is set to the time from the output of the combustion command to the supply of steam to the boiler that has stopped combustion.

The operating condition of the boiler will be described with reference to FIG. In each column of Boiler A, Boiler B, Boiler C, changes in operation priority, combustion command, and steam generation amount are described.
The number of boilers burned, which is determined from the steam requirement, is shown in the upper row. In the first state, the boiler A is the first place, the boiler B is the second place, and the boiler C is the third place. The number of combustions determined from the steam pressure value in the pressure detection device 3 is the first place boiler and the second place.
If two of the two boilers are to be burned, the first boiler A and the second boiler B will burn.
When it is time to change the operation priority, the unit number control device 2
Then, the integrated values of combustion time in each boiler are compared, and the shorter the combustion time, the higher the priority of operation is changed.

In the order change in the left column of FIG. 2, the boiler A is the first
Assume that boiler C changed from third to first, boiler C changed from third to first, and boiler B remained second after the change.
In this case, since the number of boilers that are burning is two, if the order is changed, the boiler A that was burning stops combustion and the boiler C that has stopped burning starts new combustion. Will be done. The number-of-units control device 2 is a boiler C that starts combustion by raising the operation priority.
Is a combustion start boiler, and the other boilers A and B are distinguished as other boilers.

When the operation priority order is changed, the unit control device 2 changes the order of the boiler C, which is a combustion start boiler, prior to other boilers. The boiler C changes the order prior to the time of changing the operation priority by the preceding time T1, and sets the operation priority of the boiler C to the first rank. Since the unit control device 2 outputs the combustion command to the first-rank boiler and the second-rank boiler, it also outputs the combustion command to the boiler C, and the boiler C that has received the combustion command prepares for combustion. Start. At this time, the boilers A and B remain at the first and second positions because the operation priorities have not been changed, and the unit number control device 2 has the first and second boilers A and C. The combustion command is output to the boiler B, which is the highest rank.

Even if the boiler C receives a combustion command, it takes time to start generating steam. Therefore, steam is generated immediately after the combustion command is output to the boiler C as before. There will be two units, boiler A and boiler B. After that, in the boiler C, preparation for combustion is advanced, and when the operation priority change timing is reached, the operation priorities of the boiler A and the boiler B are changed to the new third and second positions. The number of units burned is 1st and 2nd, so the unit control device 2
A command to stop combustion is output to boiler A
Stop the combustion of boiler A. If the combustion is stopped, the generation of steam is stopped, and then the steam is supplied by the boiler B and the boiler C.

Even if the combustion command is sent to the boiler C which has stopped the combustion, the combustion cannot be started immediately,
If the boiler that burns is replaced by simultaneously issuing the command to stop combustion and the command to start combustion, the steam pressure may decrease due to insufficient steam supply. However, the boiler that newly starts combustion must start combustion preparation prior to the change of the operation priority order, and must be able to supply steam when the operation priority order is changed, so that the steam when the operation priority order is changed It is possible to prevent pressure drop.

The right column of FIG. 2 is the operation priority change timing 24 hours after the left column, and the boiler A is from the third to the second.
Boiler B from 2nd to 1st, Boiler C to 1st
This is a time chart in which the number of combustions changes from the combustion of the first place to the number of 0s which stops all the combustions immediately before the change of the operation priority order.

In this case, the number of units burned was 0 when the operation priority was changed, and as a result, it was not necessary to burn the boiler B, but since the future cannot be accurately predicted, the unit control device In No. 2, the operation for changing the operation priority is performed assuming that the situation at the time of starting the operation for changing the operation priority continues. Since the number of boilers that are burning at this time is one, if the operation priority is changed,
The boiler C, which was burning, stops burning, and the boiler B, which has stopped burning, starts burning newly.
The number-of-units control device 2 distinguishes the boiler B which starts combustion by raising the operation priority as a combustion start boiler, and distinguishes the other boilers A and C as other boilers.

When changing the operation priority order, the unit number control device 2 changes the order of the boiler B, which is a combustion start boiler, prior to other boilers. The boiler B changes the order prior to the change of the operation priority by the preceding time T1, and sets the operation priority of the boiler B to the first priority. Since the unit number control device 2 outputs the combustion command to the first-ranked boiler, it also outputs the combustion command to the boiler B. At this time, since boiler A and boiler C have not changed their operation priorities, they are ranked third and first.
The unit control device 2 outputs the combustion command to the boiler B and the boiler C, which are the first place.

Even if the boiler B receives a combustion command, it takes time to start the generation of steam. Therefore, the steam is generated immediately after the combustion command is output to the boiler B as before. It becomes one of the boiler C. When the number of burning units becomes 0 due to the increase in steam pressure before reaching the time of changing the operation priority, the unit number control device 2 outputs a command to stop combustion to the boilers B and C, which are the first place, and the boilers B and B Stop the operation of boiler C. After that, when the operation priority is changed, the operation priorities of the boiler A and the boiler C are changed to the second and third positions, respectively.

When the steam pressure rises, the unit number control device 2
Supplies the steam more than necessary by controlling the operation of the combustion start boiler based on the operation priority as well, because it controls the combustion in order from the lowest boiler operation priority to reduce the number of combustions. The steam pressure does not rise above a predetermined range when the operation priority is changed.

FIG. 3 relates to another embodiment of the present invention. Before changing the operation priority of the boiler, the number-of-units control device 2 confirms whether or not there is a combustion stop boiler, which is a boiler that changes from the combustion state to the stop due to the operation priority being lowered. The combustion stop boiler is distinguished from other boilers that are other boilers.
When there is a combustion stop boiler, the unit control device 2 is set so that when changing the operation priority order of the boilers, the combustion stop boiler changes the order by delaying the delay time T2 from the change order of the other boilers. Keep it. The value of the delay time T2 is set to the time from the output of the combustion command to the supply of steam to the boiler that has stopped combustion.

The operating condition of the boiler will be described with reference to FIG. In the first state, boiler A is first and boiler B is second.
And the boiler C is the third rank, and the number of combustions determined by the steam pressure value in the pressure detection device 3 is the first rank if it burns two units of the first rank boiler and the second rank boiler. Boiler A and No. 2 boiler B are to burn. When it is time to change the operation priority, the unit control device 2 compares the integrated values of the combustion times in the boilers, and changes the operation priority to a higher rank for boilers with shorter combustion times.

In the order change in the left column of FIG. 3, the boiler A is the first
Assume that boiler C changed from third to first, boiler C changed from third to first, and boiler B remained second after the change.
In this case, since the number of boilers that are burning is two, if the order is changed, the boiler A that was burning stops combustion and the boiler C that has stopped burning starts new combustion. Will be done. The unit number control device 2 stops the combustion due to the lowering of the operation priority order, and the boiler A
Is a combustion stop boiler, and the other boilers B and C are distinguished as other boilers.

When changing the operation priority order, the unit number control device 2 changes the order by delaying the boiler A, which is a combustion stop boiler, from other boilers. The boiler A changes the order by delaying it by the delay time T2 from the time of changing the operation priority order, and maintains the operation priority order of the boiler A at the first order, which is the previous order, during the delay time T2. Since the unit number control device 2 outputs the combustion command to the first-ranked boiler and the second-ranked boiler, it is necessary to change the rank between the boiler C and the boiler B, which are newly ranked first and second due to the rank change. Since it has not been performed, the combustion command is output to the boiler A, which is the first place.

However, since the boiler C immediately after starting the combustion preparation cannot immediately generate steam, immediately after changing the order, there is no steam supply from the boiler C, and steam is generated. As before, there will be two units, Boiler A and Boiler B. After that, in the boiler C, preparation for combustion is advanced, and when the delay time T2 elapses, the operation priority order of the boiler A is set to the new order of the third order. Since the number of burned vehicles is the first and the second, the number control device 2 outputs a command to stop the combustion to the boiler A, which is the third, to stop the combustion of the boiler A. If the combustion is stopped, the generation of steam is stopped, and then the steam is supplied by the boiler B and the boiler C.

Even if a combustion command is sent to the boiler C that has stopped combustion, the combustion cannot be started immediately,
If the boiler that burns is replaced by simultaneously issuing the command to stop combustion and the command to start combustion, the steam pressure may decrease due to insufficient steam supply. However, the boiler that stops combustion changes the order by delaying the delay time T2 from the change in the operation priority order, so that the boiler that starts new combustion does not start steam supply until that time. Since it continues to pass, it is possible to prevent the steam pressure from decreasing when the operation priority is changed.

The right column of FIG. 3 is the time for changing the operation priority order 24 hours after the left column, and the boiler A is ranked from the third to the second.
Boiler B from 2nd to 1st, Boiler C to 1st
This is a time chart when the number of combustions is changed from the first rank to the third rank, and the moment when the number of combustions changes from the first rank combustion to 0 units where all the combustions are stopped immediately after the change of the operation priority order.

After the operation priority is changed, the number of units burned becomes 0, but at the time of changing the operation priority, the first-ranked boiler is to be burned. Therefore, the number-of-units control device 2 burns the first-ranked boiler. The operation priority change operation is performed assuming that the operation will continue. Since the number of boilers that are burning is one, when the operation priority is changed, the boiler C that was burning stops burning and the boiler B that has stopped burning
Will start burning anew. Number control device 2
Distinguishes the boiler C that stops combustion due to the lowering of the operation priority as a combustion stop boiler, and the other boilers A and B as other boilers.

When changing the operation priority order, the unit number control device 2 delays the boiler C, which is a combustion stop boiler, from the other boilers and changes the order. The boiler C changes the order by delaying the delay time T2 from the time of changing the operation priority,
Other boilers change the order of priority when the operation priority is changed.
Since the unit number control device 2 outputs the combustion command to the first-ranked boiler, it outputs the combustion command to the first-ranked boiler B due to the order change. At this time, the boiler C is still in the first position because the operation priority has not been changed, and the number-of-units control device 2 outputs a combustion command to the first-place boilers B and C. .

Even if the boiler B receives a combustion command, it takes time to start the generation of steam. Therefore, the steam is generated immediately after the combustion command is output to the boiler B as before. It becomes one of the boiler C. If the number of units of combustion becomes 0 before the delay time T2 elapses due to an increase in steam pressure, the unit number control device 2 outputs a command to stop combustion to the boilers B and C, which are the first place, and the boilers B and B Stop the combustion of the boiler C. After that, when the delay time T2 elapses, the operation priority of the boiler C is changed to the third priority.

When the steam pressure rises, the unit number control device 2
Supplies the steam more than necessary by controlling the operation of the combustion stop boiler based on the operation priority order to control the number of combustion units by stopping the combustion in order from the lowest operation priority of the boiler. The steam pressure does not rise above a predetermined range when the operation priority is changed.

[0035]

By implementing the present invention, it is possible to prevent the steam pressure from deviating from an appropriate range even when there is a boiler that stops combustion and a boiler that starts combustion by changing the operation priority. it can.

[Brief description of drawings]

FIG. 1 is a flow sheet according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation priority order and a combustion state in one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an operation priority order and a combustion state in another embodiment of the present invention.

[Explanation of symbols]

1 boiler 2 Unit control device 3 Pressure detector 4 steam header 5 Boiler operation control device

Claims (2)

[Claims] 1. A plurality of boilers are installed, operation priorities are set for each boiler, and combustion is performed by the required number of boilers in descending order of operation priority according to the required steam amount. By controlling to stop, the steam generation amount in the entire boiler is adjusted, and the operation priority is regularly changed.In a multi-can installed boiler, when the operation priority is changed, the order is moved to the top. Combustion start boilers that are changed from stop to combustion when they go up are classified into other boilers other than that, and combustion start boilers are preceded by a time T1 ahead of the change of operation priority of other boilers. A unit control device for a multi-can installed boiler, characterized by changing the operation priority. 2. A plurality of boilers are installed, operation priorities are set for each boiler, and combustion is performed by the required number of boilers in descending order of operation priority according to the required steam amount. By controlling to stop, the steam generation amount in the entire boiler is adjusted, and the operation priority order is changed regularly.In a multi-can installed boiler, when the operation priority order is changed, the order is moved to the lower order. It is divided into a combustion stop boiler that will be changed from combustion to stop when it goes down, and another boiler other than that. For the combustion stop boiler, the delay time T2 delays from the operation priority change of other boilers A unit control device for a multi-can installed boiler, which is characterized by changing priorities.