JP2016156585A - Multi-can installation boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means for previously preventing a trouble of steam shortage in a multi-can installation boiler.SOLUTION: A multi-can installation boiler comprises a plurality of boilers 1, and a number control device 11 which performs output of a combustion command to the boilers. In the multi-can installation boiler in which an operation based on a combustion command is performed in each of the boilers, if being in an operable state upon input of a combustion command from the number control device 11, information of an operation state in each of the boilers 1 is output from the boiler 1 to the number control device 11. In the number control device 11, a lapse time when a combustion command of performing combustion is output but combustion is not performed in the boiler is measured, and when combustion stop continues even when the lapse time is equal to or more than a prescribed time, it is determined that steam supply abnormality occurs in the boiler.SELECTED DRAWING: Figure 1

Description

  In the present invention, a plurality of boilers and a number control device for outputting a combustion command to the boilers are installed, and each boiler adjusts the combustion amount in accordance with the combustion command from the number control device. It relates to a multi-can boiler.

As described in Japanese Patent No. 3711645, multi-can installed boilers that install a plurality of boilers and a unit control device for determining the combustion amount of the boilers and burn the required amount of boilers are widely used. . The steam generated in each boiler is collected in a common steam header, and the steam is supplied from the steam header to the steam use location. A header header steam pressure detection device is installed in the steam header to detect the steam pressure at the gathering section, and the number control device is configured based on the steam pressure value detected by the header steam pressure detection device. Determine the required amount of combustion in When the quantity control device determines the amount of combustion in each boiler, it outputs a combustion command to the boiler that requires combustion. Each boiler operates based on a combustion command from the number control device.

For boilers installed in multiple cans, if the combustion amount is set in stages, such as high combustion, medium combustion, low combustion, and combustion stop, the unit control device uses the The number of units is determined, and a combustion command is output to each boiler so that the determined amount of combustion is obtained. The boiler that has received the combustion command is operated so as to achieve the combustion amount of the combustion command. The combustion amount in the boiler can be changed by adjusting the amount of fuel supplied to the combustion device and the amount of combustion air.

Moreover, the detection of a steam pressure value is also performed for each boiler by providing a steam pressure detection device in each boiler and detecting the steam pressure for each boiler. In the invention described in Japanese Patent No. 3711645, each boiler is provided with a pressure detection device, so that the pressure detection device provided in the boiler is controlled when the pressure detection device fails in the steam collecting portion. ing. As a result, even when an abnormality occurs in the pressure detection device at the steam collecting portion, it is possible to avoid an abnormal situation in which the boiler stops all cans.

In addition, the steam pressure value detected by the steam pressure detector in the boiler provided in each boiler is also used for operation control in each boiler. Combustion control in the boiler is basically performed based on the combustion command from the number control device. However, if operation cannot be performed according to the combustion command, such as when an abnormality occurs in the boiler, the combustion command from the number control device is used. Will be operated differently. When an abnormality occurs during operation of the boiler, or when combustion cannot be performed, such as when full blow is performed, combustion of the boiler is stopped by an operation control device provided individually.

For example, when the steam pressure in the boiler exceeds the set pressure for stopping combustion, the operation controller for the boiler whose pressure has increased will stop burning regardless of the combustion command from the unit control unit to ensure the safety of the boiler body. . The pressure in the boiler also rises when the pressure at the steam header that collects steam from each boiler rises. In this case, combustion is stopped by a combustion command from the number control device. However, if the steam pressure rises in a certain boiler even though the steam header pressure is not high, the boiler stops combustion in the boiler, although the combustion is commanded by the combustion command from the unit control device. It will be that. This phenomenon is because the pressure generated by the steam generated in the boiler temporarily increased compared to the steam being sent to the steam header. It recovers naturally. For this reason, combustion stops in the boiler in which the pressure has increased, but information on the occurrence of abnormality is not output from the boiler to the number control device, and the number control device does not recognize that there is an abnormality.

By the way, the steam generated in each boiler is sent to the steam header through individual steam pipes, and this steam pipe is provided with a main steam valve that can be manually opened / closed individually. Since the boiler can be disconnected from the common steam pipe by closing the main steam valve, it is often performed by fully closing the main steam valve at the time of boiler inspection work or the like. Although the main steam valve is opened to send steam after the work is completed, the possibility of ending the work with the main steam valve forgotten to open or insufficiently open cannot be denied. If the boiler is installed in a single can, it will be noticed that the steam is not supplied if the main steam valve is closed.However, in the case of a multi-can installation, the main steam valve is sufficiently opened in some boilers. Even if the steam supply from the boiler is restricted, it is difficult to notice the state of the main steam valve if the steam is supplied from another boiler. In addition, when multiple boilers are installed, a check valve is provided on the branch pipe connecting the steam collecting part and each boiler.If the check valve valve body is fixed or the flow path part is clogged, As in the case of the above, it may happen that the proper steam supply is not performed, and the operation is continued while the followability of the steam supply is lowered, which affects the production using steam. In addition, when a malfunction or indication error occurs in the pressure switch or sensor provided in each boiler, the boiler operation control device operates differently from the combustion command from the unit control device even if the steam pressure in the boiler is not high. Will do. In such a situation, the supply of steam was insufficient, and it took time to identify the cause of the abnormality.

Japanese Patent No. 3711645

  The problem to be solved by the present invention is that, in a multi-can installation boiler, it is recognized that proper steam supply is not possible due to a failure of the steam supply line in some boilers, and it is possible to prevent a steam shortage trouble in advance. It is to provide a multi-can installation boiler.

The invention according to claim 1 is a multi-can installation boiler comprising a plurality of boilers and a number control device for outputting a combustion command to the boiler, and each boiler receives a combustion command from the number control device. If it is possible to operate, in a multi-can installation boiler that operates based on the combustion command, information on the operation status of each boiler is output from the boiler to the unit control device. The number control device outputs a combustion command for performing combustion, but measures the elapsed time when combustion is not performed in the boiler, and combustion is performed even if the elapsed time exceeds a predetermined time. When the stop is continued, it is determined that a steam supply abnormality has occurred in the boiler.

The invention according to claim 2 is that, in the multi-can installation boiler, the unit control device excludes the boiler which has been determined that the steam supply abnormality has occurred, from the unit control target, or has a lower priority of operation. It is characterized by reducing the influence of the steam supply in the whole boiler by lowering to.

By implementing the present invention, if there is a malfunction in the steam supply line such as forgetting to open the main steam valve, it is possible to detect a malfunction in the steam supply line at an early stage and report the malfunction in the steam supply line. By doing this, you can take measures such as opening the main steam valve before the actual impact occurs. Moreover, it is possible to prevent the steam supply from becoming insufficient by adjusting the number of units so that the steam supply amount is not affected.

Flow diagram of multi-can installation boiler in one embodiment of the present invention Flow diagram of boiler part in one embodiment of the present invention Time chart of operation status of each boiler in one embodiment of the present invention Time chart of operation status of each boiler in the second embodiment of the present invention

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart of a multi-can installation boiler according to an embodiment of the present invention, FIG. 2 is a flowchart of a boiler portion in FIG. 1, and FIG. 3 is a time chart of operating conditions of each boiler according to an embodiment of the present invention. It is.

The four boilers described in FIG. 1 are the same as the boilers in FIG. 2, and the four boilers 1 are installed in parallel, and the steam generated in each boiler 1 passes through the steam header 12 to use the steam. To supply. The boiler is operated by the number control device 11 based on the steam pressure value detected by the header steam pressure detection device 13 provided in the steam header 12. The number control device 11 sets a necessary combustion amount for each steam pressure value in advance, and the operation control device 10 of each boiler is set to a combustion amount determined from the steam pressure value detected by the header steam pressure detection device 13. A combustion command is output. The setting of the combustion amount in the unit control device 11 is such that the lower the steam pressure value detected by the steam pressure detection device 13 is, the more the combustion amount in the entire boiler is increased. When the amount is decreased and the steam pressure value is decreased, the total combustion amount is increased. The number control device 11 calculates a necessary combustion amount from the steam pressure value, for example, two medium combustion units and one low combustion unit, and outputs a combustion command of the determined combustion amount to the operation control device 10 of each boiler. As for the output of the combustion command, the combustion priority is determined for the boiler, and the combustion command is output in order from the boiler with the highest combustion priority. In each boiler in the figure, the priority of the first can is the first, the priority of the second can is the second, the priority of the third can is the third, and the fourth can is not subject to unit control A spare can. Therefore, if there are 2 medium combustion units and 1 low combustion unit, the unit control unit 11 outputs a low combustion combustion command to the No. 1 and No. 2 cans, and the No. 4 can The combustion command is not output because it is not subject to unit control.

The boiler 1 has a combustion device 2 at the top and supplies water through a water supply pipe 6 connected to the bottom. A water supply pump 7 is installed in the middle of the water supply pipe 6, and water is supplied to the boiler 1 by operating the water supply pump 7. The detection of the water level in the boiler is performed by the water / water separator 5 and the water level detection cylinder 8 connected to the lower part of the boiler. The water level detection cylinder 8 is provided with an electrode rod E1 that detects the presence or absence of water at the water supply stop water level (E1 water level) and an electrode rod E2 that detects the presence or absence of water at the water supply start water level (E2 water level). Water supply is controlled so that the water level in the water level detection cylinder 8 is within a certain range.

The operation control device 10 receives the combustion command from the number control device 11 and controls the amount of combustion in the boiler 1. In the case of multi-can installation, the number control device 11 outputs a combustion command to the operation control device 10 installed in each boiler, and each boiler controls the amount of combustion based on the combustion command. When the boiler 1 performs combustion control at four positions of high combustion, medium combustion, low combustion, and combustion stop, the fuel supply amount and the combustion air supply amount are adjusted so as to obtain respective combustion amounts. If high combustion is 100% combustion, medium combustion is 50%, and low combustion is 20%, supply of fuel and combustion air when a high combustion command is received When receiving a combustion command for 100%, medium combustion, the supply amount of fuel and combustion air is 50%, and when receiving a combustion command for low combustion, the supply amount of fuel and combustion air 20%. When combustion is performed in the boiler, the heat generated by the combustion heats the boiler and generates steam. The generated steam is separated from the liquid by the steam separator 5 and then sent to the steam header 12 through the steam pipe 9.

However, in a case where an abnormality occurs in each boiler and the operation according to the combustion command from the number control device 11 cannot be performed, the combustion state may be different from the combustion command. For example, in each boiler, the steam pressure in the boiler is detected by the steam pressure detection device 3 in the boiler, and when the pressure in the boiler becomes higher than the combustion stop value, a combustion command is sent from the unit control device. Even if is output, combustion is not performed. In addition, even when an abnormality occurs and combustion cannot be performed, combustion may not be performed even if a combustion command for performing combustion is output.

The number control device 11 is configured to be able to take in information on the operation state from each boiler 1. The operation state information of each boiler is transmitted from the operation control device 10 of each boiler to the number control device 11, and the number control device 11 may change the combustion command for the boiler 1 based on the operation state of the boiler. .

Each boiler is connected to a steam header 12 by a steam pipe 9, and steam is sent to the steam header 12 through a main steam valve 4 and a steam pipe 9 provided at a steam outlet portion of each boiler. A check valve 14 is provided in the branch pipe portion of the steam pipe 9 so that the backflow of steam does not occur. When operating the boiler, the main steam valve 4 must be open, but the main steam valve 4 may be forgotten to be opened, or the boiler may be operated with an insufficient opening of the main steam valve. . Here, it is assumed that the steam supply is restricted by No. 1 can.

Based on FIG. 3, the driving | running state of the boiler in this invention is demonstrated. FIG. 3 shows a combustion command to each boiler, a combustion amount in each boiler, and each boiler in a multi-can installation system in which four boilers consisting of No. 1, No. 2, No. 3, No. 4 and No. 4 cans are installed. The example of the situation of the steam pressure inside and the steam pressure at the steam header is described. In this example, the initial boiler operation priority is No. 1 for No. 1, No. 2 for No. 2, No. 3 for No. 3, and No. 4 for spare cans that are not subject to unit control. It is said. In the number control boiler, it is often performed that a spare can is installed in anticipation of the occurrence of a boiler that cannot be operated due to repairs and inspections, and the number of boilers is controlled by a boiler excluding the spare can. In addition, the operation time in each boiler is prevented from being shifted, and the boiler and operation priority order as spare cans are not fixed and are rotated and replaced once a day.

When each boiler performs four-position combustion control of high combustion, medium combustion, low combustion, and combustion stop, the unit control device 11 performs high combustion, medium combustion, low combustion or Outputs the combustion stop command. Each boiler operates based on a combustion command from the number control device 11.

In the figure, the combustion amount determined from the steam pressure in the steam header detected by the header steam pressure detecting device 13 is indicated as H for high combustion, M for medium combustion, and L for low combustion. It starts from the state of 2 combustion units and 1 low combustion unit. Combustion commands output from the unit control device are 2 medium combustion units and 1 low combustion unit, starting from the state that cans No. 1 and No. 2 are medium combustion units, and No. 3 cans are low combustion units in descending order of operation priority. Yes. In each boiler 1, steam is generated by combustion, and the generated steam is sent to the steam header 12 through the steam pipe 9.

At that time, if the steam supply is restricted by the main steam valve 4 provided in the middle of the steam pipe 9, the steam supply to the steam header 12 is hindered. When the main steam valve 4 is not sufficiently opened in the No. 1 can, when steam is generated by combustion in the boiler 1, the generated steam may come out of the boiler 1 in the No. 1 boiler. Since it is limited, the steam pressure value in the can increases greatly. Each boiler 1 is provided with an in-boiler steam pressure detecting device 3 for detecting the steam pressure in each boiler. When the pressure in the boiler exceeds the set pressure for stopping combustion, to ensure the safety of the boiler body. , Stop burning. In FIG. 3, the pressure in the can of No. 1 reaches the pressure at which combustion stops at time A. In No. 1 can, the combustion command from the number control device 11 is medium combustion, but No. 1 in which the pressure in the can has increased. The amount of combustion in the can is stopped.

Such an increase in the pressure in the boiler is caused by the fact that the steam generated in the boiler is larger than the steam taken out from the boiler. Absent. As the steam flows from the boiler to the steam header, the pressure rise in the boiler recovers spontaneously, and since it is temporary, it is not determined that there is an abnormality. Information on the occurrence of an abnormality is not transmitted. In this case, no abnormality has occurred in the boiler, but combustion is not performed in the boiler. However, when the main steam valve 4 is closed, the steam in the boiler does not flow to the steam header 12, so the abnormal state does not recover naturally. In such a case, the unit control device 11 determines whether or not the steam supply is abnormal. Information on the operation state in each boiler 1 is output to the number control device 11, and the number control device 11 monitors the operation state in each boiler and responds when an abnormality occurs. When the combustion control command for combustion is output from the number control device 11 to the boiler 1, but the combustion is not performed in the boiler, the operation control device 10 indicates that the number control device 11 has stopped combustion. Output information. And in the number control apparatus 11, the time when the boiler has stopped combustion is measured. In FIG. 3, after the time A, a command for combustion is given to the No. 1 can, but since the No. 1 can does not burn, the elapsed time from the time A is measured. .

For the first can in which the main steam valve 4 is not sufficiently opened, the amount of steam supplied from the boiler is less than usual even when the combustion command for medium combustion is issued from the unit control device 11, so The steam supply amount is insufficient, and the steam pressure at the steam header 12 is reduced. In the number control device 11, when the steam pressure in the steam header 12 decreases, the combustion command is changed in a direction to increase the combustion amount in the boiler. In FIG. 3, the combustion amount determined from the header pressure at time B is MMM, and a combustion command for changing the combustion amount to medium combustion is output to the No. 3 can that had previously output a low combustion combustion command. . At this time, the No. 1 can stops combustion, and the No. 2 and No. 3 can supply steam by medium combustion. However, even in this state, the steam supply amount is insufficient, and the steam pressure value at the steam header 12 is further decreased.

In the number control device 11, when the information indicating that the combustion is stopped due to the high steam pressure is input from the boiler although the combustion designation for performing combustion is output from the number control device 11, Measure elapsed time. When this measurement time is equal to or longer than the predetermined time, it is determined that some abnormality has occurred in the steam supply system, and notification of the steam supply abnormality is made. In FIG. 3, when combustion has not been resumed at time C when a predetermined time has elapsed from time A, an alarm for notifying steam supply abnormality is issued.

If the person in charge of the boiler is informed that the main steam valve 4 is not open by notifying the steam supply abnormality, the person in charge of the operation takes measures such as opening the main steam valve 4. When the abnormality is removed by opening the main steam valve 4, the steam in the boiler is sent to the steam header 12 through the steam pipe 9, so that the pressure is reduced in the boiler, and the boiler 1 may burn. become able to. However, simply notifying the steam supply abnormality does not cope with the absence of the person in charge of the boiler on the spot, and the steam supply continues to be insufficient. Therefore, the number control device 11 changes the number control target boiler and changes the priority order in addition to the notification of the steam supply abnormality. In the number control device 11, the boiler in which the steam supply abnormality occurred at the time C, in this embodiment, the first can is a spare can not be controlled, and the fourth can previously used as a spare can is the number control target boiler. And

In the number control device 11, the No. 4 can targeted for the number control is given the third operation priority, the No. 2 can second and the No. 3 third No. Move up to second place. Since the combustion command at the time when the operation priority was changed was from the first to the third, and the combustion was medium combustion, the No. 4 can with the operation priority ranked third would also perform combustion. In the No. 4 can, when a combustion command for medium combustion is input, preparation for performing combustion by medium combustion is started. In the preparation process, after performing pre-purge to ventilate the boiler, ignition to ignite the burner, flame stabilization to start the combustion with low combustion and stabilize the flame, Combustion is performed by combustion.

After time D when the middle combustion is started in the No. 4 can, the steam supply amount from the boiler exceeds the steam usage amount, and the steam pressure at the steam header 12 portion detected by the header steam pressure detection device 13 The value is rising. After that, at time E, the main steam valve 4 of the No. 1 can is opened by the operator of the boiler, and when the steam in the boiler is sent to the steam header 12 in the No. 1 can, the pressure in the can is lowered. When the opening degree of the main steam valve 4 is insufficient, the pressure in the boiler and the pressure in the steam header 12 are greatly different, but after the main steam valve 4 is opened, the pressure in the steam header 12 is linked. Will change.

FIG. 4 relates to the second embodiment. The difference from the above embodiment is that the number of installed units is the same, but no spare cans are set, and the entire four installed boilers are subject to unit control, and unit control is performed with four boilers. To do. In the second embodiment, the header pressure detected by the header steam pressure detector 13 starts from the MML- pressure range. -Means combustion stop. In the unit control device 11, the first and second boilers are medium combustion, the third boiler is low combustion, and the fourth boiler is combustion stopped. Start with a combustion command output. In this case, if the operational priority is No. 1 for No. 1 can, No. 2 for No. 2, No. 2 for No. 3, No. 3 for No. 3, No. 4 for No. 4 can, then No. 1 and No. 2 Means that a low combustion is output to the No. 3 can and a combustion command for stopping the combustion is output to the No. 4 can.

The internal pressure of the can detected by the internal steam pressure detection device 3 of each boiler is the same as the pressure in the steam header 12. However, since the No. 1 can is in a state where the opening of the main steam valve 4 is insufficient and the steam supply is restricted, the value of the inside pressure of the No. 1 can is completely different from the other boilers. It has become a movement. At the beginning of the figure, the No. 1 can burns with medium combustion because a combustion command for medium combustion is output. Then, since the opening degree of the main steam valve 4 is insufficient, the internal pressure of the can is rapidly increased to the pressure at which combustion is stopped. When the pressure inside the can rises to the combustion stop pressure in the No. 1 can, the No. 1 can stops the combustion. At this time, the No. 2 can burns with medium combustion and the No. 3 can burns with low combustion, but the steam supply amount is insufficient, so the pressure at the steam header 12 is reduced. When the header pressure detected by the header steam pressure detection device 13 is in the MMM- pressure category, which is one level lower, the priority is changed from low combustion to medium combustion in the third-ranked boiler. The combustion amount is changed from low combustion to medium combustion.

In this case as well, the number control device 11 issues a command for combustion to the No. 1 can, but the elapsed time in a state where the No. 1 can is not combusting is measured. When the measured time reaches the time for determining the steam supply abnormality, the unit control device 11 determines that the steam supply abnormality has occurred, notifies the steam supply abnormality, and changes the operation priority order. Do.

The change in the operation priority order changes the operation priority order of the boiler that has been determined to be abnormal in steam supply to the lowest order, and the vacant order is sequentially moved up to the lower boilers. In the second embodiment, the boiler that caused the steam supply abnormality was the No. 1 can. Therefore, the No. 1 operation priority was set to the lowest 4th, and the 2nd No. 2 can. The first place, the third place No. 3 can will be changed to the second place, and the fourth place No. 4 can will be changed to the third place. As a result of this change in operation priority, the combustion command output from the unit control device 11 has the fourth rank No. 1 can from medium combustion to combustion stop, and the third rank No. 4 can stop burning. The combustion state is changed between No. 1 and No. 4 cans by changing the combustion command. Due to the change in the operation priority, the No. 1 can that has caused the steam supply abnormality is not required to be burned, and the No. 4 can burns, and the steam pressure value in the steam header 12 is recovered. After that, the steam supply abnormality due to insufficient opening of the main steam valve of the No. 1 can be determined, the abnormal steam supply is reported, and the normal state can be recovered by opening the main steam valve of the No. 1 can. . Then, the pressure value in the No. 1 can is linked to the pressure value of the steam header. By doing in this way, even when the steam supply is restricted by the main steam valve 4, it is possible to promptly notify the user of an abnormal state and prevent the steam supply from becoming insufficient.

The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Combustion apparatus 3 Steam pressure detection apparatus in a boiler 4 Main steam valve 5 Steam separator 6 Feed water piping 7 Feed water pump 8 Water level detection cylinder 9 Steam piping 10 Operation control device 11 Unit control device 12 Steam header 13 Header section steam pressure Detection device 14 Check valve

Claims (3)

It is a multi-can installation boiler consisting of a plurality of boilers and a unit control device that outputs a combustion command to the boiler, and each boiler can be operated when a combustion command is input from the unit control device. For example, in a multi-can boiler that is operated based on a combustion command, information on the operation status of each boiler is output from the boiler to the number control device, and the number control device performs combustion. When the combustion command is output but the boiler does not perform combustion, the elapsed time is measured, and if the elapsed time is equal to or longer than the predetermined time and the combustion stop continues, A multi-can installation boiler, characterized in that it determines that a steam supply abnormality has occurred in the boiler. The multi-can installation boiler according to claim 1, wherein the unit control device is configured to issue an abnormality report for notifying the occurrence of the steam supply abnormality when it is determined that the steam supply abnormality has occurred. A multi-can installation boiler. 3. The multi-can installation boiler according to claim 1 or 2, wherein the unit control device excludes a boiler that has been determined that a steam supply abnormality has occurred, from a unit control target, or lowers the operation priority to a lower level. The multi-can installation boiler characterized by reducing the influence of the steam supply in the whole boiler.

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