JPH06337110A - Industrial furnace with rotary heat accumulating burner - Google Patents

Abstract

PURPOSE:To obtain an industrial furnace with a high accuracy and favorable responsiveness in which the continuous operation of the furnace can be carried out even when a trouble of a rotary heat accumulating burner is happened and the damage of attached equipments including the rotary heat accumulating burner can be avoided. CONSTITUTION:A by-pass passage 15 through which an oxidizer passage 12 communicating with the oxidizer duct of a rotary heat accumulating burner 30 communicates with an exhaust gas passage 13 communicating with an exhaust gas duct with each other is provided. Cut-off valves 16 and 17 are respectively mounted in the by-pass passage 15 and the exhaust gas passage 13. The opening and closing of the cut-off valve 16 of the by-pass passage 15 side and the cut-off valve 17 of the exhaust gas passage 13 side is controlled in accordance with a signal from a burner monitor means 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial furnace equipped with a rotary heat storage burner that uses the heat of exhaust gas after combustion to heat an oxidant.

[0002]

2. Description of the Related Art For industrial furnaces such as tube type furnaces and steel furnaces,
In order to save energy, a heat recovery type combustion device that uses the heat of exhaust gas after combustion to heat an oxidant is often used.

Examples of such a combustion device include, for example, JP-A-1-222,102 and JP-A-4-101,19.
There is one disclosed in Japanese Patent No. In this combustion apparatus, a heat storage material made of a heat resistant material and having air permeability is attached to a wall of a combustion chamber of an industrial furnace, and a duct portion is connected to the heat storage body. An oxidant duct through which an oxidant circulates and an exhaust gas duct through which exhaust gas after combustion in the combustion chamber circulates are formed in this duct portion. The oxidant duct has an oxidant passage through which the oxidant circulates, and the exhaust gas duct includes an exhaust gas passage through which exhaust gas after combustion in the industrial furnace circulates. While rotating relatively, the oxidant is heated through the heat storage body heated by the exhaust gas.

The term "oxidizing agent" as used herein is a generic term for gases containing oxygen atoms such as pure oxygen and nitrogen oxide, or oxygen gas mixed gas such as air and oxygen-enriched air.

This combustion device itself is called a rotary heat storage burner and heats the oxidizer while rotating the heat storage body. Therefore, a heat exchanger for heat recovery is separately provided to heat the oxidizer. However, the structure is simple, and the oxidizer can be immediately heated by the heat storage material heated by the exhaust gas, which is extremely energy-saving.

[0006]

However, in this rotary heat storage burner, the heat storage body or the duct portion is relatively rotated by the power of an electric motor or an air motor to perform heat exchange between the exhaust gas and the oxidizer. Therefore, when the rotation stops, heat exchange cannot be performed. As a result, the high-temperature exhaust gas flows out through the same flow path of the heat storage body, and in the worst case, the heat resistance limit of the induction blower or the control valve provided downstream of the rotary heat storage burner is exceeded. Cross over
May be damaged in a short time.

Further, in this industrial furnace, the combustion chamber is in a substantially closed state, and the exhaust gas is discharged only to the heat storage portion. Therefore, when the relative rotation is stopped, if the combustion is temporarily continued by using air at room temperature, the rotary heat storage burner becomes the same as a normal burner, and the exhaust gas is sucked into the rotary heat storage burner. In addition, the oxidizer is not preheated.

For this reason, in order to keep the amount of heat transfer constant while continuing combustion using air or the like at room temperature as an oxidant, the amount of combustion must be increased by an amount corresponding to preheating of the oxidant.

When the combustion amount is increased in this way, the amount of exhaust gas also increases as the combustion amount increases. Therefore, unless the size of the induction blower is increased and the induction capacity is increased, the furnace pressure rises, making it difficult to send the oxidizer. In the worst case, there is a possibility of misfire.

The present invention has been made to solve the problems associated with the prior art described above. A first object of the present invention is to supply the oxidizer by switching the passage even if an abnormality occurs in the rotary heat storage burner. And to enable continuous operation of the furnace.

A second object is to reliably prevent the rotary heat storage burner and the induction blower from being damaged by supplying an oxidizing agent at room temperature to the heat storage body of the rotary heat storage burner in which an abnormality has occurred.

A third object of the present invention is to detect an abnormality of the rotary heat storage burner by temperature, current value or rotation speed, and to provide an industrial furnace with good responsiveness and high accuracy.

A fourth purpose is to continue combustion even in the abnormal rotary heat storage burner, reduce the load on the normally operating rotary heat storage burner, and generate heat required from the heated fluid side. To maintain the pattern as it was before the abnormality.

A fifth object is to reduce the load on the induction blower by directly discharging the exhaust gas from the exhaust gas discharge port even if an abnormality occurs in the rotary heat storage burner and the load on the induction blower increases. To increase the flexibility of.

[0015]

SUMMARY OF THE INVENTION The present invention which achieves the above object has an oxidant duct having a breathable heat storage body, a duct portion communicating with the heat storage body, and an oxidant flowing in the duct portion. A rotary heat storage burner that forms an exhaust gas duct through which the exhaust gas after combustion flows and heats the oxidizer by the heat of the exhaust gas through the heat storage body while relatively rotating the heat storage body and the duct portion. In the industrial furnace provided on the wall of the combustion chamber, a bypass passage that connects the oxidant passage communicated with the oxidant duct of the rotary heat storage burner and the exhaust gas passage communicated with the exhaust gas duct with each other is provided. The industrial furnace is characterized in that it is provided with open / close shutoff valves in the bypass passage and the exhaust gas passage.

In the combustion chamber of the industrial furnace according to the present invention, the bypass passage is provided with a shut-off valve which is normally fully closed, and the exhaust passage is provided with a shut-off valve which is normally fully opened. By a signal such as electrical or fluid or light from the burner monitoring means that detects the operating state of the burner,
The bypass valve on the bypass passage side is fully opened, and the shutoff valve on the exhaust gas passage side is fully closed.

The oxidizer passage of the industrial furnace according to the present invention is connected to a forced air blower for controlling the flow rate of the oxidizer by a damper, and the opening of the damper is adjusted so that the indicated value of the oxygen concentration in the combustion chamber becomes a set value. Is controlled.

The combustion chamber of the industrial furnace according to the present invention is provided with a plurality of rotary heat storage burners, and an appropriate number of oxidants are collectively supplied to the oxidant passages connected to the rotary heat storage burners. Bypass passage communicating with the oxidant header portion continuously provided with the exhaust header provided so as to collectively discharge an appropriate number of exhaust gas passages through which the exhaust gas discharged from the rotary heat storage burner flows And a shutoff valve that can be opened and closed is provided in the bypass passage and the exhaust header or the exhaust passage downstream of the exhaust header.

In the industrial furnace according to the present invention, the bypass passage is provided with a shutoff valve which is normally closed at all times, and the exhaust header or the exhaust passage downstream of the exhaust header is provided with a shutoff valve which is normally opened at normal times. , The shutoff valve of the bypass passage side is fully opened by a signal such as an electrical or fluid or light from a burner monitoring means for detecting the operating state of the rotary heat storage burner, and the shutoff valve of the exhaust passage or the exhaust header is opened. It is characterized in that the shutoff valve on the exhaust gas passage side on the downstream side is fully closed by the control means.

The oxidizer header portion of the industrial furnace according to the present invention is
It is characterized in that the damper is connected to a forced air blower for controlling the flow rate by a damper, and the opening degree of the damper is controlled so that the indicated value of the oxygen concentration in the combustion chamber becomes a set value.

The burner monitoring means of the industrial furnace according to the present invention operates with a thermometer for measuring the exhaust gas temperature at the outlet of the heat storage body, an ammeter for measuring the current value of the heat storage body or the electric motor for moving the duct, or an overcurrent. It is characterized by being configured by using at least one of a tachometer for measuring the number of revolutions of the thermal relay, the heat storage body or the duct portion.

In the combustion chamber of the industrial furnace according to the present invention, an exhaust gas discharge port is communicated, an openable and closable control valve is provided in the exhaust gas discharge port, and pressure detection means for detecting the pressure inside the combustion chamber of the combustion chamber is provided. When it is detected that the pressure is equal to or higher than a predetermined pressure, the control means adjusts the opening degree of the control valve.

In the combustion chamber of the industrial furnace according to the present invention, an exhaust gas outlet is communicated, a control valve that can be opened and closed is provided in the exhaust gas outlet, and an induction blower that attracts the exhaust gas in the exhaust gas passage is exhibited. When the blower monitoring means for detecting the attracting capacity detects that the capacity is equal to or higher than a predetermined capacity, the control means adjusts the opening degree of the control valve.

In the combustion chamber of the industrial furnace according to the present invention, an exhaust gas discharge port is communicated, an openable and closable control valve is provided in the exhaust gas discharge port, and pressure detection means for detecting the pressure inside the combustion chamber of the combustion chamber is provided. When it is detected that the blower monitoring means that detects that the pressure is equal to or higher than a predetermined pressure and that the attracting fan that attracts the exhaust gas in the exhaust gas passage has a predetermined capacity or more, the control means controls the control. It is characterized in that the opening of the valve is adjusted.

[0025]

According to the present invention, when the burner monitoring means detects an abnormal operation of the rotary heat storage burner, the shutoff valve of the bypass passage is opened, and only the oxidant passage in the rotary heat storage burner where the abnormality has occurred is detected. The oxidant at room temperature is also supplied from the exhaust gas passage, and while cooling the exhaust gas passage and the heat storage body, it is mixed with the fuel supplied into the furnace and combustion continues.

Since this combustion is combustion with the normal temperature oxidant, the amount of exhaust gas increases by an amount corresponding to the sensible heat of the oxidant preheating, which causes an increase in the pressure in the combustion chamber.

However, the blower monitoring means has detected that the pressure detecting means has detected that the pressure in the combustion chamber has become equal to or higher than the set pressure, and / or that the induced blower has reached a predetermined attracting ability, for example, the rated ability. Sometimes, the control means adjusts the opening of the control valve in the exhaust gas outlet, so even if the amount of exhaust gas increases, part of the exhaust gas is discharged directly from the exhaust gas outlet, and the combustion chamber pressure is below the set value. become,
And / or the induced draft fan exhibits a predetermined attracting ability. As a result, the pressure in the combustion chamber can be prevented from rising and the required amount of oxidant can be secured.

In addition, when there are a plurality of rotary burners that are operating normally, the load on these rotary heat storage burners or the load on the induction blower is reduced, and the heat generation pattern required from the heated fluid side is reduced. It can be maintained in the same manner as before the abnormality and the flexibility as an industrial furnace can be increased.

In an industrial furnace having a plurality of rotary heat storage burners, if expensive bypass valves are provided in each bypass passage and an exhaust gas passage, not only the passage becomes complicated but the structure becomes complicated, but also the entire apparatus is Get expensive.

However, in the present invention, the exhaust gas passages and the oxidant passages of the plurality of rotary burners are grouped by the header portions, and the bypass passages that connect the header portions are provided, and the exhaust header or the downstream side of the exhaust header is provided. If a shut-off valve is attached to the exhaust gas passage, the structure will be simplified and the cost will be improved.

As a means for detecting the operating state of the rotary heat storage burner, the temperature of the exhaust gas discharged from the rotary heat storage burner becomes high when the heat exchange between the exhaust gas and the oxidant is not smoothly performed. Even if it is a thermometer that detects the temperature of exhaust gas, if the relative rotation of the heat storage body or the duct section stops or becomes slower than the set number of revolutions for some reason, the current value of the electric motor responsible for this rotation becomes high. Therefore, it may be an ammeter that detects this current value or a thermal relay that operates by overcurrent, or even a tachometer that directly measures the number of revolutions of the heat storage body or the duct part. It is possible to detect an abnormality in the operating state of the rotary heat storage burner, resulting in a highly responsive and highly accurate industrial furnace.

[0032]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic vertical cross-sectional view showing a tubular heating furnace according to an embodiment of the present invention, in particular, a box-type heating furnace which is one type of the heating furnace, and FIG. 2 is a sectional view taken along line 2-2 in FIG. FIG.

The box-type heating furnace shown in FIG. 1 has a substantially sealed combustion chamber 10 made of a refractory material such as refractory bricks,
A plurality of rotary heat storage burners 30 are provided on the floor wall 10a of the combustion chamber 10, and a large number of heating tubes 11 are erected inside the combustion chamber 10. As shown in FIG. 2, a heating fluid such as naphtha or gasoline flows into the heating pipe 11 through the inlet pipe 11a, and the heating pipe 11 meanders and flows in the combustion chamber 10. After being heated by an open flame, the outlet pipe 11b is heated. It is becoming more spilled.

On the other hand, the rotary heat storage burner 30 is connected to an oxidant passage 12 for supplying an oxidant and an exhaust gas passage 13 for discharging exhaust gas. The oxidant passage 12 and the exhaust gas passage 13 are connected by a bypass passage 15. It is in communication. The bypass passage 15 has a shutoff valve 16 which is normally closed.
However, shut-off valves 17 that are normally fully opened are attached to the exhaust gas passages 13, respectively. By opening and closing these shut-off valves 16 and 17, the oxidant is supplied only from the oxidant passage 12, or the oxidant passage 12 and the exhaust gas passage. It can be supplied from both of the above.

In this embodiment, as is clear from FIG.
Since six rotary heat storage burners 30 are provided in the combustion chamber 10, the oxidant passages 1 connected to each burner 30 are connected.
Two exhaust gas passages 13 and six bypass passages 15 are also provided. These six oxidant passages 12 are put together by an oxidant header portion 18 so that the oxidant is supplied to each oxidant passage 12 collectively, and the six exhaust gas passages 13 are also exhaust headers. Organized by section 19,
Exhaust gas is discharged all at once.

However, if expensive shutoff valves 16 and 17 are installed in each of the exhaust gas passages 13 or the bypass passages 15, not only the structure of the entire apparatus becomes complicated, but also the equipment cost is required.

Therefore, it is more preferable to configure as shown in FIGS. This modification is, for example, two oxidant passages 12 or two exhaust gas passages 1
3 is an oxidant header portion 18a or an exhaust header portion 19a
In summary, both the header parts 18a and 19a are connected by the bypass passage 15, and the shutoff valve 17 is attached to the exhaust passage part 19a or the duct D of the exhaust gas passage on the downstream side communicated with the exhaust header part 19a. ing. However, the number of bundles of the oxidant passage 12 and the exhaust gas passage 13 is not limited to two, and in some cases, three or more oxidant passages 12 or exhaust gas passages 13 may be connected to the oxidant header portion 18a or the exhaust header. Part 19
You may put together by a.

As shown in FIG. 2, the oxidizing agent header portion 18
A forced air blower 20 is continuously provided through the duct D. The forced draft blower 20 is designed to take in the oxidizer that has passed through the silencer 21 after the flow rate of the oxidizer is controlled by the damper 22. In this forced air blower 20, the indicated value of the oxygen concentration meter 7 (see FIG. 1) for measuring the oxygen concentration in the combustion chamber 10 is input to the control means C as shown in FIG. Damper 22
Is controlled so that the indicated value of the oxygen concentration meter 7 is always a predetermined value.

On the other hand, the exhaust header section 19 is provided with an induction blower 24 via a duct D and a damper 23.
The exhaust gas taken out by the induction blower 24 is further discharged through a duct D (see FIG. 1) from an exhaust gas discharge port 25 connected to the ceiling 10b of the combustion chamber 10.
In the exhaust gas outlet 25, the control valve 2 which is normally fully closed is provided.
6 is attached. The opening of the control valve 26 detects that the pressure detecting means 28 including a pressure gauge for detecting the pressure in the furnace of the combustion chamber 10 is equal to or higher than a predetermined pressure, and attracts the exhaust gas in the exhaust gas passage 13. Induction blower 2
When the blower monitoring means 27 for detecting the attracting ability exerted by 4 detects that the blower monitoring means 27 has a predetermined ability or more, it is adjusted by the control signal from the control means C.

Here, the blower monitoring means 27 detects whether or not the induction blower 24 has reached the full capacity rating and protects the induction blower 24 itself. In this embodiment,
The blower monitoring means 27 determines whether or not the induction blower 24 has reached the rating from the current value of the electric motor M1 for driving the induction blower 20 and the output value of the valve actuation device K1 of the control valve 26, and the induction blower is detected. 24 are protected. More specifically, the current value of the electric motor M1 is detected by an ammeter, and the output value of the valve operating device K1 of the control valve 26 measures, for example, the valve operating amount. Then, the measured value of the blower monitoring means 27 is input to the control means C as shown in FIG. 5, and when the current value reaches a predetermined value, the signal from the control means C causes the valve operation of the control valve 26. In the case of a device K1, for example a pneumatically actuated piston, the air pressure is regulated and the control valve 26
Are trying to control.

Further, in this embodiment, the rotary heat storage burner 3 is used.
It also has burner monitoring means 29 for detecting whether or not the operating state of 0 is abnormal. The burner monitoring means 29 is a temperature detecting means 29 including a thermocouple or the like for measuring the exhaust gas temperature of the heat storage outlet of the rotary heat storage burner 30, which will be described in detail later.
a, a current value detecting means 29b including an ammeter or the like for measuring a current value of the heat storage body or the electric motor for moving the duct, a rotation speed detecting means 29c including a tachometer or the like for measuring the rotation speed of the heat storage body or the duct portion, and Although it is a thermal type relay 29d that operates by overcurrent attached to the ammeter 29b, in some cases, the temperature detecting means 29a, the current value detecting means 29b, the rotation speed detecting means 29c or the thermal type relay 29d can be used. , At least one may be used.

In the abnormal rotary heat storage burner, the amount of heat radiated to the combustion chamber 10 is smaller than that in the normal case because the heat exchange between the exhaust gas and the oxidant is not performed, and the outlet temperature of the fluid to be heated is reduced. Will go down. To adjust this, a thermometer 8 including a thermocouple or the like is provided at the outlet of the heating pipe 11, and the measured value of the thermometer 8 is the control means C.
Entered in. When the measured value becomes equal to or lower than a predetermined temperature, the control means C outputs a valve opening adjustment signal to the flow control valve 9 to increase the fuel amount.

In FIG. 5, signals from a fuel flow meter and a combustion air flow meter (not shown in FIG. 1) are also input signals to the control means C. These are the set values of the outlet temperature of the fluid to be heated. This is a control method used to always operate with a feeling of excess air when the load changes that requires a large increase or decrease in fuel from the relationship with the indicated value.

In the figure, all the symbols "K2-6" are valve actuating devices.

As shown in FIG. 6, the rotary heat storage burner 30 has a burner 31 for injecting a flame upward.
And a heat storage body 32 functioning as a heat exchange member attached to the floor wall 10a of the combustion chamber 10, a duct portion 33, and the like.

The heat storage body 32 is made of, for example, ceramics having a large number of honeycomb-shaped holes, and is fixedly installed in the opening 34 formed in the floor wall 10a of the combustion chamber 10.

On the anti-combustion chamber side of the heat storage body 32, there is formed an oxidant duct 33a for supplying an oxidant and an exhaust gas duct 33b for exhausting the exhaust gas after burning in the combustion chamber 10 to the outside. 33 is provided so as to communicate with the heat storage body 32.

Burner 3 provided at the center of heat storage body 32
1 is a normal gas burner or oil burner,
The tip thereof faces the combustion chamber 10. The oxidant passes through the oxidant duct 33 a formed in the duct portion 33 from the oxidant passage 12, passes through the heat storage body 32 provided so as to surround the burner 31, and is jetted from around the burner 31. Has become.

Further, the outer edge of the opening 34 is
A plate 38 for supporting the burner 31 is provided, and a flange 40 of the burner body case 39 is connected to the plate 38 by a bolt 41 via a gasket G so that the burner body case 39 and the heat storage body 32 communicate with each other. ing.

The burner body case 39 covers the duct portion 33 from the outside, and has an inlet portion 42 into which the oxidant from the oxidant passage 12 is introduced and an outlet portion from which exhaust gas is discharged into the discharge passage 13. 43, an intermediate part 44 provided between the inlet part 42 and the heat storage body 32, and a drive part 45 for rotating the duct part 33.

A large diameter portion of the duct portion 33 is provided in the body portion 43a of the outlet portion 43. This large-diameter portion is a part of the oxidant duct 33a, and has a cross-section with an acute-angled fan shape as shown in FIG. In the body 43a, the oxidant duct 33a and the exhaust gas duct 33b are arranged in the circumferential direction.
Are provided so that they are alternately located. The oxidant duct 33a and the exhaust gas duct 33b are formed as independent passages from the inlet to the outlet.

The intermediate portion 44 is provided with a closing plate 49 provided to close the end of the body portion 43a of the outlet portion 43 on the side opposite to the heat storage body, a support plate 50 provided at the lower end of the duct portion 33, and the like. And have.

The drive unit 45 includes a closing plate 49 and a supporting plate 5.
Sealing member S and bearing J respectively provided at the inner end portion of 0
A sprocket 51 fixed between both bearings J and a drive gear 52 rotated by a motor M2 are connected via a chain 53 so as to rotate the duct portion 33 rotatably supported by the motor M2. is there. The duct part 33 has 2
Since it is supported in good balance by the two bearings J, J, it can be rotated at a relatively high speed.

The inlet portion 42 has a base pipe 54 and a branch pipe 55.
And T are connected in a T shape, one end of the base pipe 54 is closed by a lid 56, and the other end is attached to a support plate 50 provided at an end of the duct portion 33. In addition,
Reference numeral "57" in FIG. 6 is a rectifying plate.

Next, the operation of the embodiment will be described. First, during normal operation when the industrial furnace is operating normally, the shutoff valve 17 in the exhaust gas passage 13 of each rotary heat storage burner 30 is fully open, and the shutoff valve 15 in the bypass passage 16 is fully closed. The exhaust gas (white arrow) flowing from the rotary heat storage burner 30 passes through each exhaust gas passage 13 and is collected in the exhaust header portion 19 by the induction blower 24.
Downstream of the control valve 26 inside, it enters the exhaust gas outlet 25 and is released to the atmosphere.

On the other hand, the oxidizer (solid arrow) is pressurized by the forced air blower 20, enters each oxidizer passage 12 via the oxidizer header 18, is preheated by the rotary heat storage burner 30, and is introduced into the combustion chamber 10. To be done. At this time, since the shutoff valve 16 of the bypass passage 15 is fully closed, the oxidant is not mixed in the exhaust gas.

When the thermometer 29a in the exhaust gas passage 13 or the ammeter 29b of the electric motor M2 for rotation of the rotary heat storage burner 30 or the thermal relay 29d detects an abnormality, the abnormality of the rotary heat storage burner 30 is detected. The shutoff valve 17 in the exhaust gas passage 13 is fully closed, and the bypass passage 1
The shutoff valve 16 in 5 is fully opened. As a result, a part of the oxidant passing through the oxidant passage 12 is also supplied to the rotary heat storage burner 30 from the exhaust gas passage 13 via the bypass passage 15. Therefore, the high temperature combustion exhaust gas
Therefore, it is possible to prevent damage to these devices without continuous circulation to the induction blower 24, and it is possible to continue combustion even in the rotary heat storage burner 30 in which an abnormality has occurred.

In this tube type heating furnace, the pressure or flow rate of the combustion gas or combustion oil is controlled by the flow rate control valve 9 so that the outlet temperature of the fluid to be heated becomes a set value, and in the induction blower 24, the combustion chamber 10 The suction side damper 23 of the induction blower 24 is adjusted so that the indicated value of the pressure gauge 28 becomes the set value.
Is controlled, and in the forced draft fan 20, the combustion chamber 1
The suction side damper 22 of the forced draft fan 20 is controlled so that the indicated value of the oxygen concentration meter 7 of 0 becomes the set value.

However, if there is a rotary heat storage burner 30 in which an abnormality occurs during operation, the amount of heat radiated to the combustion chamber 10 becomes smaller than in the normal case because the heat exchange between the exhaust gas and the oxidant is not performed, and the above-mentioned The outlet temperature of the heating fluid will drop.

In order to adjust this, the flow rate control valve 9 is activated by the signal from the control means C, and the fuel amount is increased. As the combustion amount increases, the pressure in the combustion chamber 10 increases, the oxidant inflow amount decreases, and the oxygen concentration in the combustion chamber 10 decreases. In order to adjust this, the induction blower 24
Then, the dampers 23 and 22 of the forced draft fan 20 are opened.

Here, the forced blower 20 and the induced blower 24
When the loads are compared, the oxidant flows into all the rotary heat storage burners 30, whereas the exhaust gas is not exhausted from the abnormal rotary heat storage burner 30, and the rotary heat storage burner 30 that is operating normally Since only the air is exhausted from the inside, the increase ratio of the pressure loss on the exhaust gas side becomes high, and the load of the induction blower 24 first approaches the rating.

Therefore, it is possible to continue the operation by detecting that the induction blower 24 is close to the rated value and opening the control valve 26 in the exhaust gas discharge port 25 until the pressure in the furnace becomes equal to or lower than the set value.

If it is assumed that the abnormal rotary heat storage burner 30 is extinguished and the amount of the abnormal heat is stored in the normally operating rotary heat storage burner 30, the normally operating rotary heat storage burner 30 is The combustion amount increases, and the heat absorption amount of the heating pipe 11 in the vicinity thereof increases. However, such a local increase in temperature may cause decomposition, alteration, or coking of the fluid to be heated in a tubular heating furnace that mainly handles hydrocarbon as the fluid to be heated. Coking is an important issue to be prevented in the field of tubular heating furnaces, and it is necessary to avoid extinguishing the burner for a long time leading to local heating. From this point of view, the present apparatus, which is capable of continuing combustion even in a rotary heat storage burner in which an abnormality has occurred, is effective in achieving uniform heating.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the claims. In the above-described embodiment, the oxidant passage 33a of the duct portion is rotated, but the heat storage body 30 side may be rotated, or relative rotation between the heat storage body and the inflowing fluid passage may be used. Further, in the above embodiment, a plurality of rotary heat storage burners are provided in one combustion chamber, but it is also possible to provide one rotary heat storage burner in one combustion chamber. Further, in the above-described embodiment, the heat storage body of the rotary heat storage burner uses ceramics as the heat resistant material, but it may be a heat storage body made of metal or the like.

[0065]

As described above, according to the present invention, the following effects can be obtained. 1) Even if an abnormality occurs in the rotary heat storage burner, the combustion air is supplied by switching the passage, so that the furnace itself can be continuously operated without stopping. 2) Since normal temperature air is supplied to the heat storage body of the rotary heat storage burner in which an abnormality has occurred, damage to the rotary heat storage burner and the induced draft fan can be reliably prevented. 3) Since the abnormality is detected by the temperature, the current value, the number of revolutions, etc., it is possible to prevent the rise of the pressure in the combustion chamber and to secure the necessary amount of oxidant, and the response is good and the accuracy is high. 4) Combustion can be continued even with the abnormal rotary heat storage burner, which not only reduces the load on a healthy rotary heat storage burner but also maintains the heat generation pattern required from the heated fluid side as before the abnormality. it can. 5) When an abnormality occurs in the rotary heat storage burner, the load on the induction blower increases, but since the exhaust gas is discharged directly to the exhaust gas discharge port, the load on the induction blower can be reduced and the flexibility of the industrial furnace can be increased. You can 6) In an industrial furnace provided with a plurality of rotary heat storage burners, each bypass passage and exhaust gas passage are grouped by a header portion, and a bypass passage communicating with each header portion is provided, and an exhaust header or a downstream side of the exhaust header is provided. Since the shutoff valve is attached to the exhaust gas passage, the structure is simplified and it is advantageous in cost.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing a box-type heating furnace according to an embodiment of the present invention.

FIG. 2 is a sectional equivalent view taken along line 2-2 in FIG.

FIG. 3 is a plan view corresponding to FIG. 2 showing a modified example of the present invention.

FIG. 4 is a side view of a main part of FIG.

FIG. 5 is a block diagram showing a control system of the embodiment.

FIG. 6 is a schematic sectional view showing an example of the rotary heat storage burner of the embodiment.

7 is a cross-sectional view taken along line 7-7 of FIG.

[Explanation of symbols]

10 ... Combustion chamber, 10a ... Bottom wall, 12
... oxidant passage, 13 ... exhaust gas passage, 15
... Bypass passage, 16 ... Shutoff valve, 17 ... Shutoff valve, 18 ... Oxidizing agent header part, 19
… Exhaust header part, 20… Push blower, 2
2 ... Damper, 24 ... Induction blower, 2
5 ... Exhaust gas exhaust port, 26 ... Control valve, 27 ...
Induction blower monitoring means, 28 ... Pressure detecting means, 29
... Burner monitoring means, 29a ... Thermometer, 29b
... Ammeter, 29c ... Tachometer, 29d ...
Thermal type relay, 30 ... Rotary heat storage burner,
32 ... Heat storage body, 33 ... Duct part, 3
3a ... Oxidizing agent duct, 33b ... Exhaust gas duct, C ... Control means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuhiko Oki 2-12-1, Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kako Construction Co., Ltd. (72) Hitoshi Kaji, Tsurumi-chuo, Tsurumi-ku, Yokohama, Kanagawa Chome 12-1 Chiyoda Kakoh Construction Co., Ltd. (72) Inventor Yoshiyuki Yusa 2-12-1, Tsurumi Chuo, Tsurumi-ku, Yokohama, Kanagawa Prefecture Chiyoda Kakoh Construction Co., Ltd. (72) Inventor Yasuo Hirose Naka, Yokohama, Kanagawa Horai ▲ Lai ▼ Town 2-4, 7 7 Furnace Techno Co., Ltd.

Claims (10)

[Claims] 1. An oxidant duct having an air permeable heat storage body, the duct portion communicating with the heat storage body, the oxidant flowing through the duct portion, and the exhaust gas duct through which exhaust gas after combustion flows. It is an industrial furnace in which a rotary heat storage burner, which is formed to heat the oxidizer by the heat of the exhaust gas through the heat storage body while rotating the heat storage body and the duct portion relatively, is provided on the wall of the combustion chamber. And a cutoff valve that can be opened and closed in the bypass passage and the exhaust gas passage, while providing a bypass passage that mutually connects the oxidant passage that communicates with the oxidant duct of the rotary heat storage burner and the exhaust gas passage that communicates with the exhaust gas duct. An industrial furnace characterized by being equipped with. 2. A bypass valve which is normally closed in the bypass passage and a shutoff valve which is normally opened in the exhaust gas passage are provided in the bypass passage, and the shutoff valve detects the operating state of the rotary heat storage burner. The shutoff valve on the bypass passage side is fully opened and the shutoff valve on the exhaust gas passage side is fully closed by a signal from the burner monitoring means such as electrical or fluid or light. The industrial furnace according to claim 1, wherein: 3. The oxidant passage is connected to a forced air blower that takes in the oxidizer after controlling the flow rate of the oxidizer by a damper, and controls the opening degree of the damper so that the indicated value of the oxygen concentration in the combustion chamber becomes a set value. The industrial furnace according to claim 1, characterized in that. 4. A plurality of rotary heat storage burners are provided in the combustion chamber, and a plurality of rotary heat storage burners are connected so as to collectively supply an appropriate number of oxidizers to the oxidant passages respectively connected to the rotary heat storage burners. The oxidant header section and a bypass passage communicating with an exhaust header provided so as to collectively discharge a suitable number of exhaust gas passages through which exhaust gas discharged from the rotary heat storage burner flows are provided, and The industrial furnace according to claim 1, wherein an openable / closable shutoff valve is provided in the bypass passage and the exhaust header or an exhaust passage downstream of the exhaust header. 5. A shutoff valve that is normally closed in the bypass passage, and a shutoff valve that is normally opened in the exhaust header or an exhaust gas passage downstream of the exhaust header are provided in the bypass passage. The shutoff valve on the bypass passage side is fully opened by a signal from the burner monitoring means for detecting the operating state of the rotary heat storage burner such as electrical or fluid or light, and the exhaust header or the exhaust passage downstream of the exhaust header is opened. The industrial furnace according to claim 4, wherein the shutoff valve on the side is controlled to be fully closed by the control means. 6. The oxidizer header section is connected to a forced air blower that takes in the oxidizer after the flow rate of the oxidizer is controlled by a damper, and the opening degree of the damper is adjusted so that the indicated value of the oxygen concentration in the combustion chamber becomes a set value. The industrial furnace according to claim 4, wherein the industrial furnace is controlled. 7. The burner monitoring means is a thermometer for measuring the exhaust gas temperature at the outlet of the heat storage body, an ammeter for measuring the current value of the electric motor for moving the heat storage body or the duct, or a thermal relay operated by overcurrent. Alternatively, the industrial furnace according to claim 2 or 5, wherein at least one of the tachometers for measuring the number of revolutions of the heat storage body or the duct portion is used. 8. An exhaust gas outlet is connected to the combustion chamber, and a control valve which is normally in a fully closed state is provided in the exhaust gas outlet to detect a pressure in the furnace of the combustion chamber. The industrial furnace according to claim 2 or 5, wherein the control means adjusts the opening degree of the control valve when the means detects that the pressure is equal to or higher than a predetermined pressure. 9. The combustion chamber is connected to an exhaust gas outlet, and a control valve that is normally in a fully closed state is provided in the exhaust gas outlet, and an induction blower that attracts the exhaust gas in the exhaust gas passage is provided. 6. The control means adjusts the opening of the control valve when the blower monitoring means for detecting the attracting ability to be exerted detects that the blower monitoring means has a predetermined ability or more. Industrial furnace. 10. The combustion chamber is connected to an exhaust gas discharge port, a control valve is arranged in the exhaust gas discharge port, and pressure detection means for detecting the pressure inside the furnace of the combustion chamber is detected to be equal to or higher than a predetermined pressure. And, when it is detected that the blower monitoring means for detecting the attracting ability exerted by the induced blower for attracting the exhaust gas in the exhaust gas passage has a predetermined capacity or more, the control means adjusts the opening degree of the control valve. The industrial furnace according to claim 2 or 5, characterized in that.