JPH0968310A - Industrial furnace with heat recovery type combustion equipment and combustion control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain continued combustion of burners by preventing the occurrence of abnormality in other heat exchangers than those in which abnormality has occurred. SOLUTION: An exhaust path 6 is provided with a stack damper 7 normally closed being allowed to control the opening or closing thereof. It is judged whether abnormality occurs in a heat exchanger of each rotary regenerative burner RRX or not based on measured values of a temperature sensor TIA for measuring the temperatures of exhaust gases discharged from the heat exchangers and a measured value of a current sensor XA for measuring current fed to a motor M used as drive source of a rotation drive mechanism of the heat exchangers. When the occurrence of the abnormality is detected, the stack damper 7 is opened while an induction blower 11 is stopped and an induction blower damper 11a is closed. Thus, the rotary regenerative burners RRX operate as normal burner requiring no preheating of an oxidizing agent with any heat exchanger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat recovery type in which a burner and a heat exchanger for preheating an oxidizer supplied to a combustion chamber by utilizing heat of exhaust gas discharged from the combustion chamber are combined. The present invention relates to an industrial furnace provided with a combustion device and a combustion control method therefor.

[0002]

2. Description of the Related Art In an industrial furnace such as a tube heating furnace and a steel furnace, a burner and a heat exchanger for heating an oxidizer such as air by using heat of exhaust gas are combined from the viewpoint of energy saving. The heat recovery type combustion device is widely used. In the present specification, "oxidizing agent" generally means pure oxygen,
A general term for gases containing molecular oxygen such as air and oxygen-enriched air. However, in special cases, it is also possible to use an oxidizing element or compound such as halogen or nitric oxide as the oxidizing agent.

Examples of the heat recovery type combustion apparatus described above include US Pat. No. 4,856,492, European Patent Application Publication No. 526,172A2, British Patent Application Publication No. 2,208,423A, and Japanese Patent Laid-Open No. Hei 1 No. 159511, Japanese Patent Laid-Open No. 1-222102, Japanese Patent Laid-Open No. 5-256.
No. 423, for example.

US Pat. No. 4,856,492,
JP-A-1-159511 and JP-A-5-2564
The heat recovery type combustion device of the first type shown in Japanese Patent No. 23 basically uses two or more heat storage bodies for one burner. In these devices, a heat storage body is arranged in each of two or more passages which are, for example, an exhaust gas passage or an oxidant passage. Then, the heat storage bodies arranged in one or more passages are heated by the exhaust gas, and the oxidant is supplied to the remaining passages to preheat the oxidizer by the sensible heat of the heat storage bodies previously heated by the exhaust gas. That is, heat exchange is performed by alternately flowing the exhaust gas and the oxidant through the passage containing the heat storage body. In order to alternately flow the exhaust gas and the oxidant in the passage, specifically, a plurality of switching valves are used.

European Patent Application Publication No. 526,1
72A2, British Patent Application Publication No. 2,208,42
In the heat recovery type combustion device of the second type shown in No. 3A and Japanese Patent Laid-Open No. 1-222102, an oxidant duct and an exhaust gas duct are provided for one heat storage body provided for one burner. An intake / exhaust duct provided with is provided, and a relative rotational movement is generated between the heat storage body and the intake / exhaust duct (usually an oxidant duct). By doing so, exhaust gas is discharged through a part of one heat storage body to heat the heat storage body, and the oxidant is supplied to the inside of the furnace through the rest of the heat storage body to preheat the oxidant by the sensible heat of the heat storage body. can do.

As a modification of the second type of heat recovery type combustion device, as shown in Japanese Patent Laid-Open No. 7-113509, a switching means for rotating is provided between the heat storage body and the duct, and the switching means is provided. In some cases, the oxidant is preheated by rotating it.

When using these heat recovery type combustion devices for continuous combustion with a burner, an abnormality occurs in the heat exchanger,
A situation may occur in which heat exchange cannot be performed completely or sufficient heat exchange cannot be performed. The abnormality in the heat exchanger is, for example, a case where the switching valve cannot be switched in the first type heat recovery combustion device, and the second type heat recovery combustion device uses intake and exhaust air. An object is sandwiched between the duct and the heat storage body, or a failure occurs in the rotary drive mechanism, and the relative rotation speed between the heat storage body and the intake / exhaust duct decreases or becomes zero. Is.

[0008] A plurality of heat recovery type combustion devices are used in one industrial furnace. If an abnormality occurs in the heat exchanger of one heat recovery type combustion device and heat exchange is not performed, It is known that the temperature of the exhaust gas flowing through the induction blower and the control valve exceeds the heat resistance limit of these devices, and the life of these devices becomes extremely short. As a technique for solving such a problem, a technique disclosed in Japanese Patent Laid-Open No. 6-337110 has been proposed for the second type heat recovery type combustion device. JP-A-6-337110
In the technology disclosed in Japanese Patent Publication, regarding the heat exchanger in which the abnormality occurred, the abnormality occurred while cooling the heat storage body by supplying the oxidant at room temperature not only from the oxidant duct but also from the exhaust duct. Maintain the burner burner corresponding to the heat exchanger. At this time, this burner is operating as a normal burner that does not recover heat. Then, in the heat recovery type combustion device equipped with the remaining normal heat exchanger, the combustion is continued while recovering the heat as it is.

[0009]

[Problems to be Solved by the Invention]
A sufficient effect can be obtained when a large number of heat recovery type combustion devices are installed or when the heat exchanger in which an abnormality has occurred can be repaired within a relatively short time. However, if the number of heat recovery type combustion devices installed is not very large, or if it takes a relatively long time to repair,
It has been found that in a heat recovery and combustion device equipped with a normal heat exchanger, an abnormality occurs in the heat exchanger or normal combustion cannot be obtained.

For example, when three heat recovery type combustion devices are installed in one industrial furnace, an abnormality occurs in the heat exchanger of one heat recovery type combustion device, and this abnormality occurs. If only the oxidant is supplied from the heat exchanger, the amount of exhaust gas discharged from the remaining two heat recovery combustors is smaller than that when the three heat recovery combustors are normal. The oxidizer is supplied to three heat recovery combustors, which is 1.5 times as much. However, in the heat storage body of the heat exchanger in which the abnormality has occurred, the temperature is low because only the oxidant flows, and the pressure loss in the heat storage body is small. Therefore, excess oxidant is supplied to the burner corresponding to this heat exchanger through the heat exchanger in which the abnormality has occurred. On the other hand, the amount of oxidant supplied from the normal heat exchanger to the burner corresponding to this heat exchanger is smaller. However, in the normal heat exchanger, the temperature of the heat storage body becomes high because the amount of exhaust gas increases as described above. As a result, the heat exchange is unbalanced, the temperature of each part of the normal heat exchanger rises, and abnormalities occur in the normal heat exchanger one after another, which makes it impossible to maintain continuous combustion of each burner. appear.

An object of the present invention is to reliably prevent an abnormality from occurring in a heat exchanger other than the heat exchanger in which the abnormality has occurred, and to maintain continuous combustion of each burner. An object of the present invention is to provide an industrial furnace provided with a heat recovery type combustion device and a combustion control method thereof.

Another object of the present invention is to provide an industrial furnace and a combustion control method therefor capable of accurately detecting an abnormality of a heat exchanger and quickly and easily responding to the occurrence of an abnormality of the heat exchanger. .

Another object of the present invention is to provide an industrial furnace and a combustion control method therefor capable of reliably preventing the life of a heat exchanger and an induction blower used for discharging exhaust gas through the heat exchanger from being shortened. Especially.

Still another object of the present invention is to provide an industrial furnace and a combustion control method therefor capable of continuing continuous combustion without trouble even if an abnormality occurs in one or more heat exchangers.

Still another object of the present invention is to operate another heat exchanger within a safe range without causing an abnormality in the other heat exchangers other than the heat exchanger in which the abnormality has occurred, and An industrial furnace and its combustion control that allow a heat recovery combustion device operating as a normal combustion device to be re-activated as soon as possible before the generated heat exchanger is repaired or replaced. To provide a method.

[0016]

DISCLOSURE OF THE INVENTION An industrial furnace equipped with a heat recovery type combustion apparatus which is an object of improvement or combustion control of the present invention has a plurality of burners that continuously burn and a plurality of burners. It is provided with a plurality of heat exchangers each provided one by one, and an air blower provided for the plurality of heat exchangers. It should be noted that one heat recovery type combustion device is configured by combining one burner and one heat exchanger. The heat exchanger has one or more heat storage bodies having air permeability, and the heat exchanger discharges exhaust gas through the heat storage bodies to store the heat in the heat storage bodies and to accommodate the oxidant through the stored heat storage bodies. It is connected to a blower to supply the burner.

The heat exchanger referred to herein is used in the first type heat exchanger and the second type heat recovery type combustion device used in the above-mentioned first type heat recovery type combustion device. Included are any of the second type of heat exchangers described. The heat exchangers of the first type and the second type are both provided for one or more heat storage bodies and operate when attracting exhaust gas from the furnace and when pushing the oxidant into the furnace. It has a movable mechanism (switching valve, rotary duct, etc.) that enables exhaust of exhaust gas and supply of oxidant through one or more heat storage bodies, and a power source (motor, etc.) for this movable mechanism.
The first type heat exchanger (switchable heat exchanger) will be specifically described. The first type heat exchanger has a plurality of heat storage bodies, and a heat storage body selection mechanism (switching valve or the like) is used. The induction blower discharges exhaust gas through the selected one or more heat storage bodies, and the oxidant is supplied into the furnace through the one or more heat storage bodies that do not discharge the exhaust gas. The second type of typical heat exchanger (rotary heat exchanger) is
It is provided with a flow path structure having an oxidant flow path and an exhaust gas flow path, and a rotary drive mechanism for imparting relative rotary motion between one heat storage body and the flow path structure. In addition, JP-A-7-1
A second type of another heat exchanger (rotary heat exchanger) disclosed in Japanese Patent No. 13509 includes a rotary drive mechanism for rotating a switching means arranged between the heat storage body and the flow path structure. .

In the industrial furnace of the present invention, an exhaust passage for exhausting exhaust gas from the furnace without passing through a plurality of heat exchangers is provided. Generally, this exhaust passage is a passage that connects the furnace and the chimney. A damper that can be controlled to open and close is provided in this exhaust passage. As this damper, a normally closed damper or a stack damper is used. Further, a heat exchanger abnormality detection device for detecting abnormality of the plurality of heat exchangers and a burner combustion maintenance device are provided. This heat exchanger abnormality detection device includes, for example, a plurality of temperature sensors that detect the temperatures of exhaust gas passing through a plurality of heat exchangers, and one or more of which an abnormality has occurred based on the temperatures detected by the plurality of temperature sensors. Can be configured to detect the heat exchanger of the. Further, when the first type heat exchanger (switching heat exchanger) is used as the heat exchanger, the heat exchanger abnormality detection device is a power source (motor) for the movable mechanism (switching valve, rotating duct, etc.). Etc.) can be configured to detect the abnormality of the corresponding heat exchanger based on the value of the current supplied to the heat exchanger. Specifically, the second heat exchanger
When a heat exchanger of this type (rotary heat exchanger) is used, it is used as a drive source of a rotary drive mechanism that imparts relative rotary motion between one heat storage body and the flow path structure. Abnormality of the heat exchanger is detected from the current value supplied to the motor.

The burner combustion maintaining device prevents the exhaust gas from being exhausted through the plurality of heat exchangers by opening the damper provided in the exhaust passage when the heat exchanger abnormality detecting device detects one or more heat exchanger abnormalities. Control the operation of the blower. When the air blower is composed of a forced blower that supplies the oxidant to the oxidant flow path and an exhaust fan such as an induced air blower or an ejector that attracts the exhaust gas from the exhaust gas flow path, an exhaust fan such as an induced air blower Should be stopped. For example, when the exhaust gas exhausted from the induction blower is discharged through the above-mentioned exhaust passage, the exhaust can be performed through the induction blower that is naturally stopped simply by stopping the induction blower. Therefore, in order to prevent such a situation, it is preferable to close the induction blower damper provided in the induction blower. Considering the concept of the air exhaust device, it is preferable to close the air exhaust passage of the air exhaust device with a damper or the like. In this way, the exhaust gas will not be discharged from the exhaust device such as the induction blower under any conditions. Further, in this case, since the heat exchanger does not function, the movable mechanism may be stopped not only in the abnormal heat exchanger but also in the normal heat exchanger. When the switching heat exchanger is used, the selection operation of the heat storage body selection mechanism (switching valve) is stopped, and when the rotary heat exchanger is used, the rotation operation of the rotary drive mechanism is stopped. In this way, the movable mechanism is not wastefully operated, and power consumption can be suppressed.

When the heat recovery type combustion device as in the present invention is used as a normal combustion device that does not perform heat recovery, when dealing with an abnormality of the heat exchanger, it becomes impossible to maintain combustion in each combustion device. It is considered that there is almost no occurrence of. However, it cannot be said that there is a possibility that the combustion of each combustion device cannot be maintained depending on the state of the heat exchanger in which the abnormality has occurred. In order to deal with such a situation, it is necessary to set a plurality of oxidant supply amount detectors that detect the amounts of the oxidant supplied to the plurality of heat exchangers and a supply amount of the oxidant to the plurality of heat exchangers. For adjustment, a plurality of oxidant supply amount adjusting dampers provided respectively for the plurality of heat exchangers may be further provided. The oxidant supply amount detector may be any detector capable of detecting the supply amount, and may be, for example, a differential pressure gauge or a Venturi tube. Then, in the burner combustion maintaining device, the amount of the oxidant supplied to the corresponding burner through the heat exchanger in which the abnormality has occurred and the normal heat exchanger is adjusted so that the combustion of the corresponding burner can be maintained. A function for outputting a command for adjusting the opening degree of the corresponding damper for adjusting the supply of the oxidizing agent based on the output of the corresponding detector for supplying the oxidizing agent is added. The opening of the plurality of oxidant supply amount adjusting dampers may be automatically adjusted by this command, but this command may only be displayed on a display means such as a display device. In this case, a maintenance worker may adjust the opening of the oxidant supply amount adjusting damper according to the content displayed on the display means. This structure is disclosed in JP-A-6-
As in the technique disclosed in Japanese Patent No. 337110, an abnormality of the heat exchanger is caused by preventing the exhaust gas from being discharged from the heat exchanger in which the abnormality has occurred and continuing the heat exchange operation in the other heat exchangers. When applied to the technology to deal with the occurrence,
It is possible to reliably maintain the combustion of the burner in the combustion device that continues the heat exchange operation. By adopting this structure, an abnormality of the heat exchanger can be dealt with without using a bypass duct as in the technique disclosed in JP-A-6-337110.

In the combustion control method of the present invention, a plurality of heat exchangers are provided one for each of a plurality of burners that continuously burn, and the plurality of heat exchangers exhaust through one or more heat storage bodies having air permeability. A combustion control method for an industrial furnace equipped with a heat recovery type combustion device configured to store heat in a heat storage body by discharging gas and to supply an oxidant to a corresponding burner in the furnace through the stored heat storage body. set to target. When an abnormality occurs in one or more heat exchangers, the exhaust gas is stopped from being discharged through the heat storage body, and the exhaust gas is discharged from the furnace through an exhaust passage provided separately from the plurality of heat exchangers. Maintain continuous burner combustion. As a result, even if one or more heat exchangers become abnormal, it is possible to easily and reliably maintain combustion in each combustion device.

Although the heat recovery type combustion device may maintain combustion as it is as a normal combustion device that does not recover heat, it often takes time to repair or replace the heat exchanger in which an abnormality has occurred. In that case, the industrial furnace must be operated in an inefficient state. Therefore, when the heat recovery type combustion device having a normal heat exchanger is operated again as the heat recovery type combustion device, a plurality of oxidant supply amounts for detecting the amounts of the oxidant supplied to the plurality of heat exchangers are detected. A detector and a damper for adjusting the supply amount of the oxidant, which is provided for the plurality of heat exchangers and adjusts the supply amount of the oxidant to the corresponding heat exchangers, are further provided. Then, reduce the opening of the oxidant supply amount adjustment damper provided for the heat exchanger with the abnormality to the minimum range required to maintain the combustion of the burner, and then replace the exhaust gas damper of the heat exchanger with the abnormality. close. When the heat exchanger is a rotary heat exchanger, this exhaust gas damper is provided for the exhaust gas flow path of the heat exchanger so as to open and close the exhaust gas flow path, and the heat exchanger is switched. In the case of the type heat exchanger, it is provided for the exhaust gas flow passage arranged between the heat storage body and the blower. It is necessary to reduce the opening of the oxidant supply amount adjustment damper provided for the heat exchanger with the abnormality to the minimum range required to maintain the combustion of the burner in the heat exchanger with the abnormality. Since the gas does not flow, the temperature of the heat storage body is low and the pressure loss is small. Therefore, a large amount of oxidant is supplied to the burner corresponding to this heat exchanger through the heat exchanger in which the abnormality has occurred, and the combustion of this burner may become abnormally large. Here, the "minimum range" of the opening degree of the damper for adjusting the oxidant supply amount does not mean the minimum value, and the combustion of the burner is more sufficient than the combustion of the burner corresponding to another normal heat exchanger. It is in the smaller range. After that, the discharge operation of slightly discharging exhaust gas through another normal heat exchanger is started so that the amount of the oxidant supplied to the furnace through each of these other heat exchangers becomes equal, that is, each The opening degree of the oxidant supply amount adjustment damper of the other heat exchanger is adjusted so that the burner combustion is maintained. Adjusting the opening while slightly discharging exhaust gas through other heat exchangers is necessary when adjusting the opening of the oxidant supply amount adjustment damper of each heat exchanger when the number of heat exchangers is large. This is because the combustion of each combustion device will not be significantly affected even if the combustion is applied. To adjust the opening of the damper for adjusting the oxidant supply amount,
It may be automatic or manual. Then, while closing the exhaust passage, increase the amount of exhaust gas discharged through other heat exchangers,
The exhaust passage is closed to the extent that the temperature of the exhaust gas discharged through each of the other heat exchangers does not exceed the set upper limit value that is set in consideration of the limit temperature of the device that discharges the exhaust gas. The amount of the exhaust gas is increased by adjusting the opening degree of the induction blower damper when the induction blower is used to discharge the exhaust gas in the blower. The amount of exhaust gas exhausted through the other heat exchangers is set within a range in which the temperature of the exhaust gas exhausted from each heat exchanger is equal to or lower than the set upper limit value which is set in consideration of the limit temperature of the induction blower.

According to the present invention, when an abnormality occurs in one or more heat exchangers, the exhaust gas is stopped from being discharged through the heat storage bodies of all the heat exchangers, and the furnace is passed through the separately provided exhaust passages. Once exhausted, all heat recovery combustors operate as normal combustors without heat exchange. As a result, the amount of exhaust gas exhausted through the normal heat exchanger increases, the normal heat exchanger is heated above the heat resistance limit, and it is possible to prevent abnormalities from occurring in the normal heat exchanger. The continuous combustion of each burner can be reliably maintained. Moreover, even if an abnormality occurs in one or more heat exchangers and the temperature of the exhaust gas rises, the exhaust gas does not pass through the induced blower of the blower, so the induced blower is not heated above the heat resistance limit. , It is possible to reliably prevent the life of the induction blower from being shortened.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an embodiment in which the present invention is applied to a tubular heating furnace. In FIG. 1, 1 is a box-shaped heating furnace 1 having a combustion chamber 2 inside. In the hearth part 3 that constitutes a part of the furnace wall of the heating furnace 1,
A plurality of heat recovery type combustion devices 4 ... Are attached, and an exhaust passage 6 that connects a combustion chamber and a chimney (not shown) is attached to a ceiling portion 5 of the heating furnace 1. Inside the exhaust passage 6, a stack damper 7 as a normally closed damper is arranged. The drive device for the stack damper 7 is not shown in the drawing. Although not shown, the combustion chamber 2
A heating pipe P is arranged inside the. In the heating pipe P, naphtha and a heated fluid in a pretreatment (pre-purification) stage of gasoline supplied from the inlet flow, and are heated by heat of a flame from a burner (not shown) of the combustion device 4 ... The heating fluid reaches a predetermined temperature and exits from the outlet.

In this embodiment, the heat recovery type burner 4 ... Is called a rotary regenerative burner (RRX) provided with a so-called rotary heat exchanger as disclosed in the above-mentioned JP-A-1-222102. A heat recovery type combustion device is used.
An example of this rotary heat storage type burner RRX is, as schematically shown in FIG. 2, an oxidant duct that forms an oxidant flow path for one permeable heat storage body 4b provided for one burner 4a. 4c and an exhaust gas duct 4d forming an exhaust gas flow path are provided with a flow path structure called an intake / exhaust duct 4e, and relative rotation is performed by a rotary drive mechanism between the heat storage body 4b and the flow path structure. Cause movement. Normally, this rotary drive mechanism uses the motor M as a drive source to rotate the oxidant duct 4c of the heat storage body or the flow path structure. By doing so, exhaust gas is discharged through a part of one heat storage body 4b to heat the heat storage body, and the oxidant is supplied to the inside of the furnace through the rest of the heat storage body, whereby the sensible heat of the heat storage body causes the oxidant to be removed. You can preheat.

As shown in FIG. 1, each rotary heat storage type burner R
The oxidant ducts of RX are respectively connected to connection pipe lines 10 ... Which extend from a common pipe line 9 connected to a forced air blower 8 for pushing air as an oxidant. Further, the exhaust gas ducts of the rotary regenerative burners RRX are respectively connected to the connection pipe lines 13 ... Which extend from the common pipe line 12 connected to the induction blower 11 for attracting the exhaust gas. The induction blower 11 constitutes an air exhaust device.

Further, as shown in FIG. 1, an oxidant supply amount adjusting damper 14 for adjusting the supply amount of the oxidant is provided in the connecting pipeline 10 connected to the oxidant duct of each rotary regenerative burner RRX. Exhaust gas dampers 15 that control the flow of the exhaust gas are provided in the connection pipelines 13 that are respectively provided and are connected to the exhaust gas duct. The oxidant supply amount adjusting damper 14 and the exhaust gas damper 15 may be controlled to be opened and closed automatically or manually.

Further, in this embodiment, as an oxidant supply amount detector for detecting the amount of the oxidant supplied to the oxidant duct of each rotary heat storage type burner RRX in the connection pipe lines 10 through which the oxidant flows. A differential pressure gauge PdI is provided. This oxidant supply amount detector is provided to each burner for the purpose of limiting the amount of the oxidant supplied through each rotary regenerative burner RRX to the amount necessary to maintain the combustion of each burner in a normal state. Since it is provided for the purpose of equalizing the amount of the oxidizing agent, it is not always necessary to accurately measure the supply amount, and a device capable of detecting the relative supply amount is sufficient.

Further, for the motor M as a drive source of the rotary drive mechanism of each rotary regenerative burner RRX, there is provided a current sensor XA for measuring a current value supplied to the motor. This current sensor XA is a rotary storage type burner RR.
This is one of the abnormality detectors of the heat exchanger abnormality detection device that detects whether or not an abnormality has occurred in the X heat exchanger. When an abnormality occurs in the heat exchanger, the load is increased, and the relative rotation speed between the heat storage body and the flow path structure becomes slow. As a result, the current value supplied to the rotary drive source becomes larger than the steady value. Therefore, by monitoring this current value, it is possible to detect whether or not an abnormality has occurred in the heat exchanger. From this point of view, the current sensor XA does not necessarily need to be able to measure an accurate current value, but may be any one that can measure a current value relative to a certain reference value. Therefore, a thermal relay or the like that turns on when a current of a certain value or more flows can be used as the current sensor.

Further, a temperature sensor TIA for measuring the temperature of the exhaust gas flowing through each connecting pipeline is provided for the connecting pipeline 13 connected to the exhaust gas duct. This temperature sensor constitutes one of the abnormality detectors of the heat exchanger abnormality detection device that detects whether or not an abnormality has occurred in the heat exchanger of each rotary regenerative burner RRX, like the above-described current sensor. Is. When an abnormality occurs in the heat exchanger, the load is increased and the relative rotation speed between the heat storage body and the flow path structure becomes slow or becomes zero. As a result, the heat exchange efficiency in the heat exchanger is reduced, and the temperature of the exhaust gas passing through the connecting pipe line is increased. Therefore, by monitoring the temperature of this exhaust gas, it is possible to detect whether or not an abnormality has occurred in the heat exchanger. From this point of view, the temperature sensor XA does not necessarily need to be able to measure an accurate temperature, but may be any one that can measure a relative temperature with respect to a certain reference value. Therefore, a thermistor or the like can be used as this temperature sensor.

Each current sensor XA ... And each temperature sensor TI
The detection result detected in A is sent to the control device 16 including a control computer. Inside the control device 16,
A determination unit of the heat exchanger abnormality detection device that determines whether or not an abnormality has occurred in the heat exchanger based on the detection result from each sensor using the control computer is configured. In addition, when the heat exchanger abnormality detection device detects an abnormality in one or more heat exchangers inside the control device 16 using the control computer, the stack damper 7 is opened, and the induction blower 11 is opened.
The burner combustion maintenance device that closes the induction blower damper 11a (closes the exhaust flow passage of the exhaust device) and outputs a command to stop the operation of the motor M of the rotary drive mechanism and the induction blower 11 is configured. Note that FIG. 1 does not show a command system for stopping the motor M to stop the rotation drive mechanism.

Next, in this heating furnace, it is assumed that an abnormality has occurred in the heat exchanger of, for example, one rotary regenerative burner RRX. Temperature sensor TIA provided for the heat exchanger
Alternatively, the detection value of the current sensor XA becomes large, and the determination unit of the heat exchanger abnormality detection device configured in the control device identifies the heat exchanger in which the abnormality has occurred. When the heat exchanger abnormality detection device detects an abnormality in the heat exchanger, the burner combustion maintaining device provided inside the control device outputs a stack damper full opening command to the drive mechanism (not shown) of the stack damper 7. At the same time, the burner combustion maintenance device outputs an induction blower stop command to a drive device (not shown) of the induction blower 11 to stop the induction blower, and further outputs an induction blower damper full closing command to a drive mechanism (not shown) of the induction blower damper 11a. Then close the induction blower damper. At the same time, the burner combustion maintenance device outputs a motor stop command to the drive device of the motor M of the rotary drive mechanism of each heat exchanger to stop each motor M.

In this state, the oxidant is supplied to the combustion chamber from the forced draft fan 8 through the oxidant duct of the stopped heat exchanger. Since the induction blower 11 is stopped and the induction blower damper is closed, the exhaust gas is not discharged from the exhaust gas duct of each heat exchanger, and the exhaust gas in the combustion chamber 2 is fully opened. The entire amount is discharged through the exhaust passage 6 in which the stack damper 7 is disposed.
In this state, since each rotary regenerative burner RRX operates as a normal combustion device that does not perform heat exchange, even if an abnormality occurs in the heat exchanger of one or more rotary regenerative burners RRX, each combustion It is possible to reliably maintain the combustion of the burner of the device. However, depending on the state of the heat exchanger in which the abnormality has occurred, it may be preferable to adjust the supply amount of the oxidant supplied to each rotary regenerative burner RRX. In that case, the oxidant supply amount adjusting damper 14 is adjusted based on the detection value of the differential pressure gauge PdI, and each rotary heat storage type burner R is adjusted.
The supply amount of the oxidizing agent supplied to RX may be adjusted.

If an abnormality occurs in one or more heat exchangers, if the above operation is performed for the time being, it is possible to maintain the combustion of each rotary regenerative burner RRX. However, in this state, the oxidizer that is not preheated is supplied to the combustion device, so that the combustion efficiency deteriorates. Therefore, it is preferable to operate the heat recovery type combustion device having a normal heat exchanger again as the heat recovery type combustion device. In that case, by appropriately adjusting the amount of the oxidant supplied to each heat exchanger of each rotary regenerative burner RRX, the rotary regenerative burner RRX having a normal heat exchanger is used as a rotary regenerative burner. Can be able to drive.

In this case, the opening of the oxidant supply amount adjusting damper 14 provided for the heat exchanger in which the abnormality has occurred is reduced to the minimum range necessary for maintaining the combustion of the burner, and then the heat exchange is performed. The exhaust gas damper 15 of the container is closed. Since the heat exchanger abnormality detection device has already performed the identification of the heat exchanger in which the abnormality has occurred, for example, the display means is separately provided and the position or the specific number of the heat exchanger in which the abnormality has occurred is displayed on the display means. May be displayed. Further, a display light or the like may be installed in each rotary regenerative burner RRX, and the display light may be turned on to indicate that an abnormality has occurred according to an instruction from the heat exchanger abnormality detection device.

The above-mentioned exhaust gas damper 15 is connected to the connecting line 1.
It is provided so as to open and close the flow path of 3. In the heat exchanger in which the abnormality has occurred, it is necessary to reduce the opening degree of the oxidant supply amount adjusting damper 14 provided for the heat exchanger in which the abnormality has occurred to the minimum range necessary for maintaining the combustion of the burner. Since the exhaust gas does not flow, the temperature of the heat storage body becomes low, the pressure loss becomes small, and a lot of oxidant is supplied to the burner corresponding to this heat exchanger through the heat exchanger in which the abnormality occurred. The reason is that the amount of oxidant supplied to other normal burners may be reduced and incomplete combustion may occur. The simplest way is to find the minimum opening that can maintain combustion in advance and narrow it down to that opening, but if you want to increase the combustion efficiency even a little, adjust the opening to narrow it down in an appropriate range. May be. Therefore, in this embodiment, the opening degree of the oxidant supply amount adjustment damper is adjusted within the "minimum range".

After that, the induction blower damper 11a of the induction blower 11 is slightly opened to restart the operation of the induction blower, and the exhaust gas is slightly discharged through another normal heat exchanger of another rotary regenerative burner RRX. Start operation. Then, the opening degree of the oxidant supply amount adjusting damper 14 of the normal heat exchanger is adjusted so that the amount of the oxidant supplied to the furnace through these normal heat exchangers becomes equal. At this time, the opening degree of the induction blower damper 11a is such that the temperature of the exhaust gas flowing through the induction blower is lower than the heat resistance limit temperature of the induction blower, and when the number of heat exchangers is large, oxidation of each heat exchanger is performed. Even if it takes time to adjust the opening of the damper 14 for adjusting the agent supply amount, it is determined that the combustion of each combustion device is not significantly affected. The adjustment of the opening degree of the oxidant supply amount adjustment damper 14 may be automatic or manual.

Next, while gradually closing the fully open stack damper 7, the amount of exhaust gas discharged through the normal heat exchanger is increased while adjusting the opening of the induction blower damper 11a, and the normal heat exchanger is changed. The temperature of the exhaust gas discharged through each of the exhaust gas blower devices 11
The stack damper 7 is closed up to a range not exceeding the set upper limit value which is set in consideration of the limit temperature of. In addition, if the opening degree of the induction blower damper 11a is also adjusted within a range in which the temperature of the exhaust gas discharged from the normal heat exchanger and flowing through the induction blower becomes equal to or less than the set upper limit value which is set in consideration of the limit temperature of the induction blower Good.

The above description is based on the assumption that combustion is maintained in all combustion devices. However, when reactivating a normal heat exchanger, a rotary regenerative burner RR equipped with an abnormal heat exchanger
When it is safe to stop the combustion of X, the rotary regenerative burner RRX equipped with the heat exchanger in which the abnormality has occurred may be extinguished. In that case, the oxidant supply amount adjustment damper provided for the heat exchanger in which the abnormality has occurred is completely closed, and the fuel valve and steam hand valve provided for this burner may also be closed. .

FIG. 3 is a flow chart showing steps for executing the above operation. Steps ST1 to ST4
Up to the above, it is a preferable process to automate using a control computer built in the control device 16. Then, steps ST5 to ST9 are steps that do not matter whether they are executed manually or automatically.

In the above-mentioned embodiment, the present invention is applied to an industrial furnace using a heat recovery type combustion apparatus equipped with a rotary heat exchanger as a heat exchanger, but with a switching type heat exchanger. Needless to say, the present invention can be applied to a heat recovery type combustion device.

The configurations of some of the plurality of inventions described in the present specification will be listed below.

(1) A plurality of burners for continuous combustion attached to the wall of the furnace, a plurality of heat exchangers provided for each of the burners, and a heat exchanger for the heat exchangers. An air blower provided, wherein the heat exchanger includes one heat storage material having air permeability, a flow path structure including an oxidant flow path and an exhaust gas flow path, the heat storage body and the flow path. A rotary drive mechanism for imparting a relative rotary motion between the heat exchanger and the road structure, wherein the heat exchanger discharges exhaust gas through the heat storage body to store heat in the heat storage body and through the heat storage body that has stored heat. It is connected to the air blower so as to heat the oxidant and supply the oxidant into the furnace, the air blower is a forced air blower that supplies the oxidant to the oxidant flow passage, and the exhaust gas flow passage from the exhaust gas flow passage. Continuous equipped with an induction blower that attracts exhaust gas An industrial furnace equipped with a burner type burner, wherein an exhaust passage for discharging exhaust gas from the furnace to a chimney without passing through the plurality of heat exchangers, and a closed state provided in the exhaust passage at a steady state A stack damper that can be controlled to open and close, a heat exchanger abnormality detection device that detects an abnormality of the plurality of heat exchangers, and the stack when the heat exchanger abnormality detection device detects an abnormality of one or more heat exchangers An industrial furnace provided with a continuous combustion burner, comprising: a burner combustion maintaining device that opens a damper and stops the operation of the rotary drive mechanism and the induction blower.

(2) The heat exchanger abnormality detecting device serves as a temperature sensor for detecting the temperature of the exhaust gas passing through the corresponding heat exchanger and a drive source for the rotary drive mechanism of the corresponding heat exchanger. A current sensor for detecting a current value supplied to the motor, and at least one of the temperature detected by the temperature sensor and the current value detected by the current sensor exceeds a predetermined reference value. An industrial furnace provided with the continuous combustion burner according to (1), which is configured to determine that an abnormality has occurred.

(3) An oxidant supply amount adjusting damper for supplying the oxidant to the heat exchanger and an oxidant supply amount for detecting the amount of the oxidant flowing through the oxidant supply passage. The burner combustion maintenance device is further provided with a detector, the amount of the oxidant supplied to the corresponding burner through the heat exchanger in which abnormality has occurred and the normal heat exchanger is The opening degree of the oxidant supply amount adjusting damper is adjusted based on the output of the oxidant supply amount detector so that the combustion can be maintained. An industrial furnace equipped with the continuous combustion burner described in 1).

[0046]

According to the present invention, when an abnormality occurs in one or more heat exchangers, the exhaust gas is stopped from being discharged through the heat storage bodies of all the heat exchangers, and the exhaust passages are separately provided. Since the exhaust gas is discharged from the furnace, there is an advantage that continuous combustion of each burner can be reliably maintained. Moreover, even if an abnormality occurs in one or more heat exchangers and the temperature of the exhaust gas rises, the exhaust gas does not pass through the induced blower of the blower, so the induced blower is not heated above the heat resistance limit. There is an advantage that the life of the induction blower can be surely prevented from being shortened.

Further, according to the method of the present invention, even if an abnormality occurs in one or more heat exchangers, the heat recovery type combustion device having a normal heat exchanger is effectively used to maintain combustion. You can

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment in which the present invention is applied to a tubular heating furnace.

FIG. 2 is a schematic view of an example of a rotary heat storage type burner.

FIG. 3 is a flowchart showing steps of a method for performing combustion control in the embodiment of FIG.

[Explanation of symbols]

 1 Heating Furnace 2 Combustion Chamber 3 Hearth 4 Heat Recovery Combustor 5 Ceiling 6 Exhaust Passage 7 Stack Damper 8 Forced Blower 9 Common Pipeline 10 Connection Pipeline 11 Induction Blower 12 Common Pipeline 13 Connection Pipeline 14 Oxidizing Agent Supply amount adjustment damper 15 Exhaust gas damper 16 Control device PdI Differential pressure gauge RRX Rotational regenerative burner M Motor XA Current sensor TIA Temperature sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keisuke Tsutsui Inventor Keisuke Tsutsui 2-12-1, Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kakoh Construction Co., Ltd. (72) Toshiaki Yoshioka Chuo, Tsurumi-ku, Yokohama, Kanagawa 12-12-1 Chiyoda Kakoh Construction Co., Ltd. (72) Inventor Yasuo Hirose 2-4 Horai-cho, Horai-cho, Naka-ku, Yokohama-shi Kanagawa 7 Farnestechno Co., Ltd.

Claims (12)

[Claims] 1. A plurality of burners for continuous combustion, a plurality of heat exchangers provided for each of the plurality of burners, and an air blower provided for the plurality of heat exchangers. The heat exchanger has one or more heat storage bodies having air permeability, and the heat exchanger discharges exhaust gas through the heat storage bodies to store heat in the heat storage bodies and to store the heat. An industrial furnace comprising a heat recovery type combustor connected to the blower so as to supply an oxidant through the body to the corresponding burner in the furnace, wherein the plurality of heat exchangers are not passed through the industrial furnace. An exhaust passage for exhausting exhaust gas from the furnace, a damper provided in the exhaust passage for controlling opening and closing, a heat exchanger abnormality detection device for detecting an abnormality of the plurality of heat exchangers, and the heat exchanger abnormality detection The device comprises one or more of the heat exchangers And a burner combustion maintaining device that opens the damper and controls the operation of the blower so that the exhaust gas is not exhausted through the plurality of heat exchangers when an abnormality is detected. Industrial furnace equipped with equipment. 2. The heat exchanger abnormality detection device comprises a plurality of temperature sensors for respectively detecting the temperature of the exhaust gas after passing through the plurality of heat exchangers, and based on the temperatures detected by the plurality of temperature sensors. An industrial furnace equipped with a heat recovery type combustion device according to claim 1, wherein the industrial furnace is configured to detect one or more heat exchangers in which an abnormality has occurred. 3. The heat exchanger is provided for the one or more heat storage bodies, and operates when attracting the exhaust gas from the furnace and pushing the oxidant into the furnace. An industry comprising a heat recovery type combustion device according to claim 1, comprising a movable mechanism that enables exhaust of the exhaust gas and supply of an oxidant through one or more heat storage bodies, and a power source of the movable mechanism. Furnace. 4. The heat exchanger abnormality detecting device according to claim 3, wherein the heat exchanger abnormality detecting device is configured to detect an abnormality of the corresponding heat exchanger based on a value of a current supplied to the power source. An industrial furnace equipped with a recovery-type combustion device. 5. The blower comprises a forced blower for supplying an oxidant to the oxidant flow passage and an exhaust device for exhausting the exhaust gas from the exhaust passage, and the burner combustion maintaining device is When the heat exchanger abnormality detection device detects one or more abnormality of the heat exchanger, the operation of the air exhaust device is stopped and the air exhaust passage of the air exhaust device is closed. An industrial furnace equipped with the heat recovery type combustion device according to item 3. 6. The air blower comprises an air exhaust device, the heat exchanger has a plurality of the heat storage bodies, and the exhaust air passes through one or more of the heat storage bodies selected by a heat storage body selection mechanism. The exhaust gas is discharged by a device, and the oxidant is supplied into the furnace through one or more heat storage bodies that do not discharge the exhaust gas. The burner combustion maintaining device is configured to perform the heat exchange. When the device abnormality detection device detects one or more abnormalities of the heat exchanger, the heat storage body selection mechanism and the exhaust device are stopped, and the exhaust passage of the exhaust device is closed. Claim 1
An industrial furnace equipped with the heat recovery type combustion device described in 1. 7. The heat exchanger performs relative rotational movement between a flow path structure having an oxidant flow path and an exhaust gas flow path, and one heat storage body and the flow path structure. And a blower for supplying the oxidant to the oxidant flow path, and an induced blower for attracting the exhaust gas from the exhaust passage, and the burner combustion. The maintenance device, when the heat exchanger abnormality detection device detects one or more abnormality of the heat exchanger, stops the operation of the rotation drive mechanism and the induction blower, and closes the damper of the induction blower. Claim 1
An industrial furnace equipped with the heat recovery type combustion device described in 1. 8. The blower device comprises an induction blower, wherein the heat exchanger has a plurality of the heat storage bodies, and the heat blower passes through the one or more heat storage bodies selected by a heat storage body selection mechanism. The oxidizer is configured to be discharged into the furnace through the one or more heat storage bodies that do not discharge the exhaust gas, and the burner combustion maintenance device is configured to detect the heat exchanger abnormality. When the detection device detects one or more abnormalities of the heat exchanger, the heat storage body selection mechanism and the operation of the induction blower are stopped, and the induction blower damper provided in the induction blower is closed. An industrial furnace provided with the heat recovery type combustion device according to Item 1. 9. A plurality of oxidant supply amount detectors for detecting the amount of the oxidant supplied to each of the plurality of heat exchangers, and adjusting the supply amount of the oxidant to the plurality of heat exchangers. In order to further provide a plurality of oxidant supply amount adjustment dampers respectively provided for the plurality of heat exchangers, the burner combustion maintenance device is provided with the abnormal heat exchanger and the normal heat exchange. Based on the output of the corresponding oxidant supply amount detector, the amount of oxidant supplied to the corresponding burner through the reactor is such that combustion of the corresponding burner can be maintained. The industrial furnace equipped with the heat recovery type combustion device according to claim 1, wherein a command for adjusting the opening of the supply amount adjusting damper is output. 10. A plurality of heat exchangers are provided one by one for a plurality of burners that burn continuously, and the plurality of heat exchangers discharge exhaust gas through one or more heat storage bodies having air permeability. A method of controlling combustion in an industrial furnace comprising a heat recovery type combustion device configured to store heat in the heat storage body and supply the oxidant to the corresponding burner in the furnace through the stored heat storage body. When an abnormality occurs in one or more of the heat exchangers, the discharge of the exhaust gas through the heat storage body is stopped,
Combustion of an industrial furnace equipped with a heat recovery type combustion device characterized in that exhaust gas is discharged from the furnace through an exhaust passage provided separately from the plurality of heat exchangers to maintain continuous combustion of the plurality of burners. Control method. 11. A plurality of oxidant supply amount detectors for respectively detecting the amount of the oxidant supplied to the plurality of heat exchangers, and the corresponding heat exchanges provided for the plurality of heat exchangers. An oxidant supply amount adjusting damper for adjusting the supply amount of the oxidant to the reactor is further provided, and the oxidant supplied to the corresponding burner through the heat exchanger in which the abnormality has occurred and the normal heat exchanger. While measuring the amount of each using the oxidant supply amount detector,
11. The opening degree of the oxidant supply amount adjusting damper is adjusted such that the amount of the oxidant supplied to the plurality of burners is an amount that maintains combustion of each burner. A combustion control method for an industrial furnace equipped with a heat recovery type combustion device. 12. The abnormality occurs after the opening degree of the oxidant supply amount adjusting damper provided for the heat exchanger in which the abnormality has occurred is reduced to the minimum range required to maintain combustion of the burner. The exhaust gas damper of the heat exchanger is closed, and then the discharge operation of slightly discharging the exhaust gas through the other heat exchanger is started, and the oxidizer of the oxidant supplied to the furnace through each of the other heat exchangers is started. The opening of the oxidant supply amount adjusting damper of the other heat exchanger is adjusted so that the amounts become equal, and the amount of exhaust gas exhausted through the other heat exchanger is increased while closing the exhaust passage. The exhaust passage is closed to the extent that the temperature of the exhaust gas discharged through each of the other heat exchangers does not exceed the set upper limit value that is set in consideration of the limit temperature of the device that discharges the exhaust gas. Tosu Combustion control method for an industrial furnace having a heat recovery type combustion apparatus according to claim 11.