JP4032515B2 - Automatic boiler number control method - Google Patents

Description

[0001]
[Sp field of the invention]
The present invention relates to an automatic number control method in which a plurality of boilers such as steam boilers, hot water boilers, heat medium boilers and the like are installed in parallel and the number of combustion is automatically controlled according to the load conditions.
[0002]
[Prior art]
As is well known, a boiler multi-can installation system in which a plurality of boilers are installed in parallel, and the number of combustion of these boilers is automatically controlled in accordance with preset priorities in accordance with load conditions. Has been implemented. For example, in a multi-can installation system for steam boilers, a pressure in a steam header common to each boiler is detected, and the number of boilers burned is controlled based on this pressure. Compared to installing one large-capacity boiler, the boiler multi-can installation system can operate each boiler with high efficiency, which has a significant effect on energy saving and response to load fluctuations. It has the advantage that it has excellent properties.
[0003]
[Problems to be solved by the invention]
In such a boiler multi-can installation system, when an abnormality occurs in the boiler during combustion and it stops, the steam pressure drop in the steam header is detected, and the standby priority boiler is shifted to combustion. Doing so causes a response delay. That is, when the standby boiler is activated, a pre-purge of about 20 seconds is performed before the ignition operation to scavenge the combustion chamber, resulting in a response delay for that time.
[0004]
An object of the present invention is to quickly back up combustion of another boiler without causing a response delay when an abnormality occurs in the boiler.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a plurality of boilers are installed, and the boilers are controlled to high combustion, low combustion, and standby states according to load conditions according to preset priorities. When an abnormality occurs, the first boiler determines whether or not there is a low-combustion boiler when changing the combustion amount in the automatic number control method of the boiler that stops the abnormality-occurring boiler and changes the combustion amount of the other boilers . If there is a low combustion boiler in the first determination step, the low combustion boiler is changed to high combustion. If there is no low combustion boiler in the first determination step, post-purge is in progress. A second determination step is performed to determine the presence or absence of a boiler, and if there is a post-purge boiler in this second determination step, the post-purge boiler is shifted to combustion. It is characterized in that.
[0006]
According to a second aspect of the present invention, in the first aspect of the invention, when there are a plurality of post-purge boilers in the second determination step, priority is given to a boiler having a long post-purge elapsed time. It is characterized by shifting to combustion .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is applied to boilers such as steam boilers, hot water boilers, heat medium boilers, and the like. A plurality of boilers are installed in parallel, and each boiler is operated according to a load condition according to a preset priority order. Each boiler is controlled to each state of high combustion, low combustion, and standby. When an abnormality occurs in the boiler, the abnormality generating boiler is stopped, and the combustion amount of other boilers is changed in order to supplement the insufficient combustion amount. When changing the combustion amount, priority is given to changing the low combustion boiler to high combustion. Because it is burning at low combustion, when it receives a combustion amount change command signal, it can immediately shift to a high combustion state, and the shortage of combustion amount due to the stop of the abnormal boiler can be promptly performed without causing a response delay. Can be supplemented.
[0009]
Combustion amount is controlled in three stages of 100%, 50% and 0%, for example, when the maximum combustion amount is 100%, and in four stages of 100%, 70%, 35% and 0%, or more It is also possible to control in multiple stages. In the case of the above-described three-stage control, 100% is high combustion, 50% is low combustion, and 0% is in a standby state. In the case of four or more stages, the point that 0% is in the standby state is the same, but high combustion and low combustion are applied in a combination of relatively large and small combustion amounts other than 0%. To do. For example, in the case of four-stage control, 35% → 100%, 35% → 70%, or 70% → 100% may be used to supplement the shortage of the combustion amount.
[0010]
When there is no low combustion boiler when the shortage of the combustion amount is replenished, the next priority is to shift the post-purge boiler to combustion. Since the post-purge is being performed, the pre-purge can be omitted and an ignition operation can be immediately performed to shift to combustion. At that time, in order to improve safety, the post-purge for the pre-purge time is performed before the shift to combustion. However, even if the post-purge time for the pre-purge time has not elapsed, the shift to the combustion is performed. Is possible. When there are a plurality of post-purge boilers, the boiler having a long post-purge elapsed time is preferentially shifted to combustion. Also, not only when an abnormal boiler occurs but also during normal load fluctuations, if there is a combustion command signal during post-purge, it immediately shifts to combustion (preferably after the post-purge time for the pre-purge time has elapsed). To improve responsiveness to load fluctuations.
[0011]
【Example】
Hereinafter, an embodiment in which the present invention is applied to a steam boiler will be described with reference to the drawings. FIG. 1 shows an outline of a system in one embodiment of the present invention. A plurality of boilers 1 (four in the illustrated embodiment) are installed in parallel, and each boiler 1 is connected to a steam header 3 via a steam pipe 2. The steam header 3 is provided with a pressure sensor 4 for detecting the internal pressure. The pressure sensor 4 is connected to the number controller 6 through a signal line 5. This number controller 6 is connected to the controller 8 of each boiler 1 via a communication line 7. The communication line 7 connects the number controller 6, the controllers 8, and the controllers 8, and serves to transmit control signals and operation information.
[0012]
The boiler 1 is controlled to high combustion, low combustion, and standby states. For example, assuming that the maximum combustion amount is 100%, high combustion is set to 100%, low combustion is set to 50%, and standby is set to 0%. Priorities of the boilers 1 are set in the number controller 6 in advance, and the combustion amount of the boilers 1 is controlled according to the load conditions according to the priorities. The state of the load, that is, the amount of steam used by the equipment using the steam generated in the boiler 1 is determined based on the pressure in the steam header 3 detected by the pressure sensor 4, and based on the value of this pressure The combustion amount of each boiler 1 is determined. Upon startup, the boiler 1 performs a pre-purge for a predetermined time (about 20 seconds) in response to a combustion command signal, scavenging the combustion chamber, performs an ignition operation, and shifts to combustion. Further, when stopping, after receiving a stop command signal and stopping combustion, a post purge is performed for a predetermined time (about 30 seconds) to scavenge the combustion chamber and enter a standby state.
[0013]
When an abnormality occurs in any one of the boilers 1, the abnormality occurrence boiler stops due to safety control, and information indicating the occurrence of the abnormality boiler is transmitted to the unit controller 6. The number controller 6 calculates the shortage of the combustion amount due to the occurrence of the abnormal boiler, and issues a command signal for changing the combustion amount to other normal boilers in order to supplement this shortage. At that time, priority is given to changing the low combustion boiler to high combustion. If there is no low-combustion boiler, the post-purge boiler is shifted to combustion next with priority. When there are a plurality of post-purge boilers, the boiler having a long post-purge elapsed time is preferentially shifted to combustion.
[0014]
Hereinafter, the details of the control flow will be described with reference to FIG. First, it is determined whether or not an abnormal boiler has occurred (step S1). If an abnormality has occurred in the boiler, the abnormality occurrence boiler is stopped (step S2), and a combustion amount that is insufficient due to the stop of the abnormality occurrence boiler is calculated (step S3).
[0015]
Based on this insufficient combustion amount, the combustion amount of another normal boiler is changed (increased). At that time, it is determined whether or not there is a low combustion boiler (step S4). If there is a low combustion boiler, the boiler is shifted to high combustion (step S5). Since it is in the low combustion state, it is possible to immediately shift to high combustion, and the shortage of the combustion amount can be quickly compensated without causing a response delay.
[0016]
If there is no low-combustion boiler, the process proceeds to step S6 to determine the presence or absence of a post-purge boiler. If there is a post-purge boiler, the boiler is shifted to combustion (step S7). Since the post-purge is being performed, the pre-purge can be omitted and an ignition operation can be immediately performed to shift to combustion. If there is no post-purge boiler, the process proceeds to step S8, where it is determined whether there is a standby boiler. If there is a standby boiler, the boiler is activated, and after pre-purge is performed, shifts to combustion ( Step S9). If there is no waiting boiler, it means that there is no boiler capable of increasing the combustion amount, and the combustion amount cannot be replenished, so an alarm to that effect is issued (step S10). In step S11, it is determined whether or not the supplement of the insufficient combustion amount is completed. If the combustion amount is still insufficient, the process returns to step S4 and the above control is repeated.
[0017]
FIG. 3 shows an example of the combustion amount change along the time flow. Of the four boilers, the boiler with the first priority is No.1, the boiler with the second priority is No.2, the boiler with the third priority is No.3, and the boiler with the fourth priority Is No.4, No.1 is high combustion, No.2 is low combustion, No.3 is low combustion, and No.4 is in standby state. High combustion is indicated by H, and low combustion is indicated by L. In this case, since the combustion amount for one high combustion boiler is insufficient, the two boilers No. 2 and No. 3 in a low combustion state are shifted to high combustion.
[0018]
【The invention's effect】
According to the present invention, the shortage of the combustion amount due to the stop of the abnormality occurrence boiler can be quickly compensated without causing a response delay. Therefore, for example, when applied to a steam boiler, even if an abnormality occurs in the boiler, the steam amount is not insufficient, and steam at a predetermined pressure can be stably supplied.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an outline of a system in one embodiment of the present invention;
FIG. 2 is an explanatory diagram showing a control flow in one embodiment of the present invention.
FIG. 3 is an explanatory view showing an example of a change in combustion amount in the embodiment of the present invention along a temporal flow.
[Explanation of symbols]
1 Boiler 2 Steam Pipe 3 Steam Header 4 Pressure Sensor 5 Signal Line 6 Number Controller 7 Communication Line 8 Controller

Claims (2)

When multiple boilers are installed, and each boiler is controlled to high combustion, low combustion, and standby according to the load status according to the preset priority, this abnormality occurs when an abnormality occurs in the boiler While stopping the boiler, change the combustion amount of other boilers,
When the combustion amount is changed, a first determination step is performed to determine whether or not there is a low combustion boiler. If there is a low combustion boiler in the first determination step, the low combustion boiler is changed to high combustion. If there is no low combustion boiler in the first determination step, a second determination step is performed to determine the presence or absence of a boiler during post purge, and if there is a post purge purge boiler in the second determination step, An automatic number control method for boilers, characterized in that the boiler during the post purge is shifted to combustion . 2. The boiler according to claim 1, wherein in the second determination step, when there are a plurality of boilers during post purge, the boiler having a long post purge elapsed time is preferentially shifted to combustion . Automatic number control method.

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