JPH08219441A - Heat storage type burner system - Google Patents

Abstract

PURPOSE: To constitute atmosphere in a furnace of some parts having different natures locally while obtaining complete combustion with the optimum air ratio as a whole. CONSTITUTION: A plurality of burner throats 11, 11, 11, provided with heat storage bodies 9 and the flow of exhaust gas and the flow of combustion air with respect to the heat storage bodies 9 switched relatively whereby the supply of combustion air and the discharge of exhaust gas are effected alternately through the heat storage bodies 9 to effect combustion by supplying combustion air, having a high temperature near the temperature of exhaust gas to burn and injecting flames into a furnace, are provided. Combustion air, whose amount achieves the optimum air ratio as a whole but air becomes short or air becomes excessive with respect to each burner throats 11, 11, 11, is supplied to the burner throats 11, 11, 11 to effect combustion with different air ratios with respect to each burner throats 11, 11, 11 and effect complete combustion with the optimum air ratio as a whole while forming a plurality of atmospheres Z4, Z5, Z6, Z7 having different natures, such as oxidizing property, weak oxidizing property, non-oxidizing property and the like, in the furnace locally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage type burner system in which exhaust gas and combustion air are alternately passed through a heat storage body to obtain high temperature combustion air close to the exhaust gas temperature, and the combustion air is used for combustion. More specifically, the present invention relates to a heat storage burner system capable of partially setting the atmosphere in the furnace to an oxygen-deficient region or an oxygen-excess region while completely combusting as a whole, depending on the material to be heated in the furnace. Regarding

[0002]

2. Description of the Related Art As a conventional heat storage type burner system of this type, for example, as shown in FIG. 10, a set of two burners 103 directly connected to a heat storage unit is combined with an air supply system and an exhaust system. , The combustion gas after being burned alternately and used for heating the object to be heated 111 in the furnace is discharged through the burner throat 105 of the unburned burner 103, and the exhaust gas at that time is discharged. A system has been proposed in which heat is collected in the heat storage unit 109 and used for preheating the next combustion air.

Each burner 103 of this heat storage type burner system 100 is injected into a single burner throat 105 formed of burner tiles through a heat storage body 109 and combustion air preheated to a high temperature and a fuel nozzle 107. It is provided so that a stable flame is formed by ejecting the fuel to be ejected.

[0004]

Therefore, in the conventional heat storage type burner system 100, an atmosphere composed of a flame and combustion gas of a single property is used as a set of burners 105,
The objects 111 to be heated in the furnace 101 are heated alternately by forming 105.

However, it may be convenient for the furnace 101 to be able to adjust the inside of the furnace to a non-oxidizing atmosphere, an oxidizing atmosphere, or a weakly oxidizing atmosphere according to the object 111 to be heated. On the other hand, considering the pollution problem, it is necessary to completely burn the fuel at an appropriate air ratio. However, in the conventional burner system 100 in which the atmosphere in the furnace 101 is formed by a flame having a single property, it is not possible to satisfy both of these requirements at a high level, that is, to completely burn the atmosphere to obtain an unoxidized atmosphere. It was practically difficult. For example, in an iron and steel heating furnace or the like, in order to reduce scale loss, it is desirable to use non-oxidizing direct heating using a reducing combustion flame, but there is a problem that it cannot complete combustion because it forms a reducing combustion flame and causes smoke and the like. is there.

It is an object of the present invention to provide a regenerative burner system capable of completely combusting with an appropriate air ratio as a whole and forming an atmosphere in a partially non-oxidizing furnace or an atmosphere in an oxidizing furnace.

[0007]

In order to achieve the above object, a heat storage type burner system of the present invention is provided with a heat storage body, and through which the flow of exhaust gas and combustion air relative to the heat storage body is relatively switched, the heat storage body is passed through the heat storage body. Providing multiple burner throats for alternately supplying combustion air and exhausting exhaust gas and supplying high-temperature combustion air close to the temperature of the exhaust gas for combustion to eject flames into the furnace, and for each burner throat The combustion air is supplied to the burner throat in an amount such that the air ratio becomes insufficient or excessive and the air ratio becomes appropriate as a whole, and each burner throat is burned at a different air ratio to oxidize or weakly oxidize in the furnace. Alternatively, a plurality of atmospheres having different properties such as non-oxidizing properties are partially formed, and the complete combustion is performed at an appropriate air ratio as a whole.

Here, as for each of the plurality of burner throats, a single air supply system is connected to the plurality of burner throats as in the second aspect of the invention, and the combustion air in an amount that provides an appropriate air ratio as a whole. May be distributed to each burner throat and supplied, and different air ratios may be provided for each burner throat, or a plurality of burner throats may be provided by a plurality of burner systems each having an independent air supply system as in the invention of claim 7. May be formed, and the air ratio may be different for each burner within a range in which the total amount of combustion air and the total amount of fuel supplied to each burner have an appropriate air ratio.

In the second aspect of the present invention, as means for setting different air ratios for each burner throat, for example, a fixed amount of fuel is injected for each burner throat and a different amount is set for each burner throat. Combustion air is distributed, or each burner throat is equipped with an independently controllable air amount adjusting means, and the passage areas of the burner throats are set to different values for combustion in the burner throat. Controlling the amount of air, or setting the amount of air distributed to each burner throat constant and setting the amount of fuel injected from the fuel injection nozzles for each burner throat to different values, and The fuel and combustion air supplied to the burner throat are controlled for each burner throat, and different air ratios can be set for each burner throat. It is desirable to have been. Furthermore,
More preferably, the regenerative burner system of the present invention is capable of adjusting the flow rate of the combustion air in each burner throat.

Further, the heat storage type burner system according to claim 8 is provided with burner throats for excess air combustion and insufficient air combustion, respectively, to form either atmosphere around the object to be heated and further around it. Afterburning occurs when the air ratio becomes uniform as a whole, and only the radiant heat is applied to the object to be heated.

Further, in the heat storage type burner system of claim 9, the atmosphere formed by the flame and the combustion gas ejected from each burner throat intersects the burner throat so that the atmosphere intersects with the object to be heated in the furnace. The injection axes are installed so as to intersect with each other, and an afterburning zone is formed at a position away from the object to be heated so that complete combustion is achieved.

Further, in the heat storage type burner system according to the tenth aspect, the injection speed of the combustion air distributed to each burner throat can be adjusted for each burner throat.

Further, the heat storage type burner system according to claim 11 is a heat storage type in which combustion air having an appropriate air ratio as a whole is distributed to a plurality of burner throats to form excess air combustion and insufficient air combustion by one burner. At least one set of each of the burner system, the heat storage type burner system that burns with excess air, and the heat storage type burner system that burns with insufficient air is combined.

Further, in the heat storage type burner system according to the twelfth aspect, the burners are paired so that the burners are alternately exchanged and burned in a short time.

[0015]

Therefore, in the case of the heat storage type burner system according to the first aspect, the combustion air preheated to a high temperature by passing through the heat storage body is distributed to the plurality of burner throats and has a proper air ratio as a whole. Different air ratios are set for each burner throat. Therefore, flames burned at different air ratios for each burner throat are injected into the furnace. Then, depending on the air ratio, an oxygen-deficient non-oxidizing atmosphere or an oxygen-excessing oxidizing atmosphere causes the light and dark combustion formed in the furnace. At this time, since combustion is performed using combustion air preheated to a temperature close to the exhaust gas temperature in the furnace, it is expected that an increase in reaction rate and a significant increase in flammability limit will greatly contribute to stabilization of combustion. If so, even lean combustion or rich combustion at an extreme level where various difficulties are likely to occur can be easily realized. Further, in the furnace, afterburning occurs in a portion in contact with the oxidizing atmosphere around the non-oxidizing atmosphere, and complete combustion with an appropriate air ratio occurs as a whole. Then, only the heat generated by the afterburning is given to the object to be heated by radiation, and the combustion gas is discharged to the outside of the furnace through the heat storage body together with other combustion gases. Then, the heat of the exhaust gas is recovered in the heat storage body and is prepared for preheating the combustion air.

In the case of the second aspect of the present invention, the high-temperature preheated combustion air supplied from one air supply system is distributed to the burner throats. Even if the air ratio is set to be different for each burner throat, the proper air ratio can be maintained as a whole by simply performing the above control.

According to the third aspect of the present invention, only by determining the ratio of the flow rate of the combustion air distributed to each burner throat, the air ratio different for each burner throat can be determined according to the value of the determined ratio. Is set.

According to the fourth aspect of the invention, the flow passage area can be adjusted for each burner throat, and the burner throat that causes excess air combustion or insufficient air combustion can be freely switched.

Further, in the invention of claim 5, the amount of combustion air distributed to each burner throat is constant, and the air ratio as a whole is properly adjusted only by changing the amount of fuel injected into the burner throat. The air ratio can be freely set for each burner throat while maintaining it.

According to the sixth aspect of the invention, by controlling the amount of combustion air and the amount of fuel distributed for each burner throat, combustion with a desired air ratio can be realized in a more stable state.

Further, in the invention of claim 7, the combustion amount control is performed for each of a plurality of burners independent of each other, and only some burners can be operated depending on the case.

Further, according to the invention of claim 8, the object to be heated can be covered with either the non-oxidizing atmosphere or the oxidizing atmosphere, and the object to be heated is radiated with the heat due to the complete combustion occurring around the atmosphere. Since it is given, heating in a specific atmosphere can be realized without lowering heating efficiency.

Further, in the invention of claim 9, the atmosphere formed by the combustion with insufficient air and the atmosphere formed by the combustion with excessive air are surely mixed in the furnace to cause afterburning. Moreover, it occurs outside or around the atmosphere that covers the object to be heated and does not change the atmospheric components around the object to be heated.

According to the tenth aspect of the invention, when each air ratio control means changes the flow velocity of the combustion air in each burner throat, the momentum of the flame generated in the burner throat according to the change in the flow velocity is increased. It can be changed and the afterburning zone can be moved within the furnace.

Further, according to the invention of claim 11, it is sufficient to control the combustion for each individual burner system, so that the combustion control is easy.

Further, in the twelfth aspect of the present invention, the pair of burners alternately burn to form a non-reacting flame in the furnace, and the object to be heated is heated more uniformly.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

1 and 2 show an embodiment of the heat storage type burner system of the present invention. This burner system 1 has a pair of burners 3, 3 each having a heat storage body 9 and burning alternately.
Was selectively connected to the air supply system 17 or the exhaust system 25 via the flow path switching means 21, and was used to heat the object 57 to be heated from the other burner 3 while burning one burner 3. The combustion gas afterward is exhausted. The burners 3 and 3 are installed facing each other, for example, on both side walls of the furnace 7, and operate alternately. The burners 3 and 3 do not necessarily have to be opposed to each other and are separately arranged on both side walls of the furnace 7. For example, they may be arranged side by side on one wall of the furnace 7.

As the heat storage body 9, for example, a material having a large heat capacity and a high durability (for example, fine ceramics), which is relatively low in pressure loss, is formed into a honeycomb-shaped tubular shape, and the burner body is used. Alternatively, it is incorporated in the burner 3 by being housed in a casing or the like separate from this. The heat storage body 9 exchanges heat with the passing exhaust gas to recover the waste heat and preheats the combustion air with the recovered heat. The regenerator 9, 9 of each burner 3 is the duct 1
It is connected to the ports 21a and 21b of the four-way valve 21 via 5 and 15. In addition, the other port 21 of the four-way valve 21
The duct 23 of the air supply system 17 and the duct 25 of the exhaust system are connected to c and 21d, respectively. Therefore, by switching the four-way valve 21, each burner 3,
One of the three and the heat storage bodies 9, 9 is an air supply system 1
7, the other one is selectively connected to the exhaust system.

Each burner 3, 3 is provided with a plurality of burner throats 11, 11, 11, for example. Each burner throat 11, 11, 11 is located near the heat storage body 9
The tip ends are branched so as to form a book, extend in parallel, and are provided so as to open in the furnace 7, respectively. The burner throats 11, 11, 11 are set to have the same passage area. Therefore, each burner throat 11,1
A single air supply system 17 supplies the same amount of combustion air to each of 1 and 11.

Further, each burner throat 11, 11, 11
Fuel nozzles 13, 13, 13 for injecting fuel toward the inside of the burner throat 11 are attached to each of them.
Each fuel nozzle 13 of the burner 3 provided on one furnace wall is connected via a fuel pipe 27, and each fuel nozzle 13, 13, 13 of the burner 3 provided on the other furnace wall is connected to a fuel pipe 29.
Are respectively connected to the fuel supply system 31 via.
Control valves 33, 35 are provided in the middle of the fuel pipes 27, 29.
Are provided respectively. The control valves 33 and 35 are alternately opened and closed in conjunction with the switching of the four-way valve 21, and the burner throats 11 and 1 of the burner 3 on the side to which the combustion air is supplied.
It is injected only from the 1, 11 fuel nozzles 13, 13, 13. Then, the injected fuel is used for each burner throat 1
1, 11 and 11 are mixed with combustion air flowing in the furnace 7
It is jetted out and burned.

On the other hand, each burner throat 11, 11, 11
Although not shown, each fuel nozzle 13, 13, 13
A pilot burner is installed at a position where fuel injected from the vehicle can be ignited.

The air supply system 17 and the fuel supply system 31 supply combustion air and fuel in an amount that provides a proper air ratio as a whole to each burner 3, and the burner 3 as a whole is set to a proper air ratio for complete combustion. ing. On the other hand, each burner throat 1
Air ratio control mechanisms 5, 5 and 5 are respectively provided to 1, 11 and 11, and the burner throats 11, 11 and 11 are set to different air ratios.

As shown in detail in FIG. 2, the air ratio control mechanism 5 is inserted into the burner throat 11 to adjust the flow rate of combustion air, a flow rate adjusting plate 37, an adjusting plate driving means 39 and a control switch means 41. Etc.
Each flow rate adjusting plate 37 is disposed so as to face each slit 43 opened at a predetermined position of each burner throat 11, and is supported by a support mechanism (not shown) so as to be slidable in the longitudinal direction. The sliding amount of each flow rate adjusting plate 37 is limited by, for example, a stopper (not shown). Therefore, as shown by the solid line in the figure, each of the flow rate adjusting plates 37 has a housing 45.
It is possible to project from the completely retracted state into the burner throat 11 to a predetermined position indicated by a two-dot chain line in the figure. The amount of protrusion is arbitrarily set by the control of the driving unit 39. The flow passage area of the burner throat 11 changes according to the amount of protrusion of the flow rate adjusting plate 37. In addition, the flow rate adjusting plate 3
A rack 47 is provided in the half of the base end side of 7. A seal member 49 is arranged between the slit 43 and the flow rate adjusting plate 37 to hermetically seal it.

The adjusting plate driving means 39 is composed of, for example, a pinion 51, a worm gear 53, a stepping motor 55, etc., and is housed in a housing 45 fixed to the burner throat 11. The pinion 51 is rotatably attached to the housing 45 and meshes with the rack 47 of the flow rate adjusting plate 37. The worm gear 53 is fitted into the output shaft 55a of the stepping motor 55 so as not to rotate relative to it, and meshes with the pinion 51. Therefore, the output shaft 55 of the stepping motor 55
When a rotates in one direction, this rotation causes worm gear 5
3 and the pinion 51 to the rack 47, and the flow rate adjusting plate 37 is fed into the burner throat 11.
On the other hand, when the output shaft 55a of the stepping motor 55 rotates in the other direction, the worm gear 53 and the pinion 51 rotate in the opposite direction to the above case to draw the flow rate adjusting plate 37 into the housing 45 from the burner throat 11.

The control switch means 41 is electrically connected to each stepping motor 55, and these stepping motors 55 can be operated separately. That is, when the operator operates the control switch means 41, a control signal corresponding to this operation causes an arbitrary stepping motor 5
5 is output. Then, the stepping motor 55 receiving the control signal rotates the output shaft 55a in a desired direction by a desired number of revolutions in response to the control signal.

In this embodiment, the pinion 5
1, the adjusting plate driving means 39 is configured to include the worm gear 53 and the stepping motor 55. However, the adjusting plate driving means 39 is not limited to this, and the adjusting plate driving means 39 may rotate the stepping motor 55 via a rotational force transmission mechanism having a different structure. May be transmitted to the rack 47. Alternatively, for example, the flow rate adjusting plate 37 may be slid using the pressure generated in the air supply system 17 as a drive source.

In the present embodiment, the control switch means 4 electrically connected to each stepping motor 55.
Although the air ratio control mechanism 5 is configured by including 1, the invention is not limited to this, and instead of the control switch means 41, each stepping motor 55 may be automatically operated separately by microcomputer control.

In this burner system 1, the air ratio control mechanism 5 operates as follows to generate an oxygen deficient region and an oxygen excess region in the furnace 7.

When the control switch means 41 is operated to operate the adjusting plate drive means 39, a control signal is supplied from the control switch means 41 to the stepping motor 55 of the adjusting plate drive means 39. Receiving this control signal, the stepping motor 55 rotates the output shaft 55a in one direction by a predetermined number of rotations, and causes the flow rate adjusting plate 37 to project into the burner throat 11 by a predetermined amount. Therefore, the passage area of the burner throat 11 is reduced by that amount, and the distribution amount of the combustion air supplied through the heat storage body 9 is changed according to the opening ratio. Here, from the fuel nozzle 13, a fixed amount of fuel corresponding to the total amount of combustion air is equally divided and injected regardless of the flow rate of the combustion air. The amount of protrusion of the flow rate adjusting plate 37 into the burner throat 11 can be set to an arbitrary value by controlling the rotation speed of the stepping motor 55. Therefore, the air ratio is determined by the control switch means 4
With the operation of 1, the burner throat is adjusted arbitrarily. Therefore, for each burner throat 11, combustion is performed in an oxygen-deficient state to form a non-oxidizing atmosphere, or combustion is performed in an oxygen-excess state to form a weakly oxidizing atmosphere or an oxidizing atmosphere.

Next, the case where the operator controls the atmosphere in the furnace according to the type and position of the object to be heated 57 in the furnace 7 will be described. For example, a case of heating an object to be heated placed in the center of the furnace 7, for example, steel 57, will be described. In this case, it is preferable to wrap the steel 57 in an oxygen-deficient non-oxidizing atmosphere in order to suppress the oxidation.

Then, the operator operates the control switch means 41 to cause the burner throat 11 facing the steel 57, that is, the flow rate adjusting plate 37 of the burner throat 11 located at the center of the three, to protrude, and The combustion air distributed in the burner throat 11 is reduced, and the amount thereof is flowed to the other burner throats 11, 11 on both sides. As a result, the atmosphere Z4 formed by the flame and the combustion gas ejected from the central burner throat 11 is in an oxygen-deficient state, and the steel 57 is heated in the non-oxidizing atmosphere to suppress its oxidation. On the other hand, the atmospheres Z5 and Z6 formed by the flame and the combustion gas ejected from the remaining two burner throats 11 on the outer side are in an oxygen excess state.
For this reason, each combustion is a rich / lean combustion in which the flame temperature is lower than that in the case of the proper air ratio, and the generation of NOx is suppressed.

Here, as described above, the amount of combustion air and the amount of fuel supplied as the entire burner 3 are set to an appropriate air ratio. Therefore, in the region Z7 where the non-oxidizing atmosphere Z4 and the oxidizing atmospheres Z5 and Z6 are mixed, in the oxidizing atmosphere in which the unburned fuel remaining in the combustion gas of the non-oxidizing atmosphere Z4 contacts around the non-oxidizing atmosphere Z4. Reacts with residual oxygen in the after-burning to cause complete combustion. Then, without disturbing the atmosphere around the object 57 to be heated,
The heat of combustion at the time of complete combustion is given to the steel 57 which is the object to be heated by the radiation. That is, considering the burner 3 as a whole, the rich and lean combustion is performed in the furnace 7, and each of the above-described combustions proceeds at a relatively low temperature, so that the generation of thermal NOx is particularly suppressed.

Further, as the object to be heated 57, for example, a case of baking tiles will be described. In this case, it is desired that the tile 57 be baked in an atmosphere of excess oxygen so that the color development becomes good.

In this case, the flow rate adjusting plates 37 of the two outer burner throats 11 not facing the tile 57 to be heated are projected to control the amount of combustion air distributed in the burner throat 11. The amount of combustion air flowing through the central burner throat 11 is increased while decreasing the amount. As a result, the atmosphere Z5, Z formed by the flame and the combustion gas ejected from the two outer burner throats 11
6 is in an oxygen-deficient state, while the atmosphere Z4 formed by the flame and combustion gas ejected from the central burner throat 11 facing the tile 57 is in an oxygen-excessive state. Therefore, the tile 57 will be baked in an oxidizing atmosphere.

Even in this case, as in the case described above, the combustion air amount and the fuel amount supplied as the entire burner 3 are set to the proper air ratio, and the complete combustion is performed in the furnace 7 by the rich and lean combustion. To be done. Therefore, even when the positions of the oxygen-deficient region and the oxygen-excessive region in the furnace 7 are changed, the fuel is completely combusted and the generation of thermal NOx is suppressed as in the above case.

As a means for making the air ratio different for each burner throat 11, 11, 11, the fuel flow injected into each burner throat 11 is kept constant without changing the flow rate of the combustion air distributed to each burner throat 11. A means for relatively controlling the air ratio by increasing or decreasing the amount may be adopted. In this case, the burner structure is simplified because it is sufficient to control only the fuel supply system outside the burner throat 11. FIG.
Indicates an air ratio control mechanism of this type. In this air ratio control mechanism, the amount of combustion air distributed to each burner throat 11 is always set to a constant value, and each fuel nozzle 13
Only the amount of fuel injected into the burner throat 11 from is controlled. This air ratio control mechanism is composed of a flow rate control valve 63, control switch means 41 and the like. The flow control valve 63 is provided, for example, for each fuel nozzle 13
3 and the control valve 33, respectively. Each flow rate control valve 63 is preferably an electromagnetic control valve that changes its opening according to a control signal supplied from the control switch means 41. Since this electromagnetic control valve is publicly known, the description of its structure is omitted.

Therefore, the air ratio can be changed by relatively increasing or decreasing the ratio of the fuel amount to the combustion air amount.

In the excess air state, the flow control valve 63
Is completely closed so that only the combustion air flows through the burner throat 11. In this case, the fuel is injected separately into the other burner throats 11 and 11, and the fuel amount that provides the proper air ratio as a whole is supplied. In this case, combustion does not occur in the burner throat in which only the combustion air is flowed, and after being ejected into the furnace, it contacts the unburned fuel in the furnace and burns. Since the combustion air passes through the heat storage body 9 and has a high temperature close to the exhaust gas temperature, for example, about 700 to 1000 ° C., it slowly burns the fuel at the same time when it comes into contact.

Further, as the air ratio control mechanism, as shown in FIG. 4, the adjusting plate drive means 39 electrically connected to the operation switch means 41, the flow rate adjusting plate 37 and the flow rate control valve 63 are provided, and the burner is provided. The flow rate of combustion air in the throat 11 and the amount of injected fuel may be controlled simultaneously. In this case, an accurate air ratio can be set for each burner throat 11, 11, 11.

Burner system 1 configured as described above
The four-way valve 21 and the control valves 33 and 35 are interlocked with each other to switch a set of burners 3 and 3 composed of, for example, an A burner arranged on the left side and a B burner arranged on the right side in the figure. It forms a non-stationary flame in the furnace.

For example, when operating the A burner, for example, the four-way valve 21 is switched so that the A burner side is connected to the combustion air supply system, and one control valve 33 is opened and the other control valve 35 is opened. Close. Thereby, the supplied combustion air is preheated to a high temperature close to the exhaust gas temperature, for example, about 800 to 1000 ° C. while passing through the heat storage body 9, and then flows into each burner throat 11, 11, 11.
The fuel injected from each fuel nozzle 13, 13, 13 is mixed and burned. And each burner throat 11,1
Three atmospheres having different properties formed by the flame and the combustion gas jetted from Nos.
After being formed into Z6, the object to be heated 57 is heated in a specific atmosphere, for example, in a non-oxidizing atmosphere.

On the other hand, on the B burner side connected to the exhaust system, the combustion gas which has been completely burned in the afterburning zone Z7 is discharged to the atmosphere side through the air passage 15. At this time, the heat of the combustion gas (exhaust gas) after being used for heating the object to be heated is recovered by the heat storage body 9.

When a predetermined time (for example, 20 to 60 seconds) has passed since the A burner side started operating, the four-way valve 1 is switched, and in conjunction with this, one control valve 33 is closed and the other is closed. The control valve 35 is opened. This allows
Combustion air and fuel are supplied to the B burner side to start combustion, while the A burner enters a non-operating standby state. At this time, the combustion air supplied to the B burner side is preheated by the heat storage body 9 which is heated by the waste heat of the exhaust gas, and becomes extremely hot (for example, about 800 to 1000 ° C.). In the case of general combustion using combustion air at room temperature or combustion air preheated to about 300 to 400 ° C., it is difficult to burn if insufficient air or excess air. However, if the combustion air reaches such a high temperature, the temperature of the mixed gas itself will be near or above the ignition temperature of the fuel even if the air is insufficient or excessive, and the reaction rate will increase and the flammability limit will increase significantly. Contributes greatly to the stabilization of combustion and burns relatively well. The B burner side operates in the same manner as the A burner side, and an atmosphere having different properties is formed in each region Z4 to Z6 for each burner throat 11, 11, 11 to heat the object 57 to be heated in a specific atmosphere. .

After that, the A burner and the B burner alternately operate every predetermined time, and the burner system 1 repeats the alternating combustion using the combustion air of very high temperature.

In this embodiment, the case where the present invention is applied to the burner system 1 in which two sets of burners 3 and 3 are provided and alternate combustion is carried out by them, is not particularly limited to this and, for example, One burner having a plurality of burner throats and an exhaust duct for directly taking out the exhaust gas in the furnace are provided so that the fluid flows in different areas of the heat storage body between the inlet and the outlet with a constant fluid flow direction at the outlet and the inlet. It may be applied to a system in which the heat storage body and the flow path switching means (for example, see International Publication WO94 / 02784) are connected to the air supply system and the exhaust system to burn the burner at all times.

Next, a second embodiment of the burner system to which the present invention is applied will be described with reference to FIG. The same components as those of the burner system 1 described above are designated by the same reference numerals, and detailed description thereof will be omitted.

This burner system 71 is used for each burner 7
3 and 73 are provided with two burner throats 75 and 75, respectively, so that a flame ejected from one burner throat causes excess air combustion, and a flame ejected from the other burner throat causes insufficient air combustion. Has been. The burner throats 75 are arranged vertically or horizontally. Each burner throat 75 is branched from the heat storage body 9 side, and the passage areas of each burner throat 75 are set to the same value.

Each burner throat 75, 75 of this burner system 71 is provided with an air ratio control mechanism 77, 77. As shown in FIG. 6, the air ratio control mechanism 77 is composed of a set of fixed or variable orifices 77a and 77b. Each of the orifices 77a, 77b determines the ratio of the flow rate of the combustion air flowing in each burner throat 75, and is arranged closer to the heat storage body 9 than the fuel nozzle 13. These orifices 77a77b are set so that the openings thereof flow to the other burner throat 75 so as to increase or decrease the amount of combustion air flowing to the other burner throat 75. When fixing the distribution ratio of the combustion air or fixing the burner throat which should be insufficient or excessive in air, the orifice may be provided in either one.

The heat storage body 9 of each burner 73 is connected to a single air supply system and exhaust system via the duct 15 and the four-way valve 21, as in the case of the burner 3 in FIG.
Further, the fuel nozzle 13 attached to each burner throat 75 is connected to a fuel supply source (not shown) via each pipe 79 and the three-way valve 81. The first and second ports 81a and 81b of the three-way valve 81 are connected to the fuel nozzles 13 and 13 via the pipes 79 and 79, respectively, and the third port 81c is connected to the fuel supply source.

In this burner system 71, the four-way valve 21
By switching the three-way valve 81 and the three-way valve 81, respectively, combustion air and fuel are supplied to one burner 73 and the other burner 73 is connected to an exhaust system and used as an exhaust means.

One of the burners 73 from the air supply system
The combustion air supplied to is preheated while passing through the heat storage body 9 and then distributed to the plurality of burner throats 75.
The combustion air is influenced by the orifices 77a and 77b and flows more in the upper burner throat 75 than in the lower burner throat 75. However, the same amount of fuel is supplied to each fuel nozzle 13 from the fuel supply source.
Therefore, if the combustion air supplied to the lower burner throat 75 close to the heated object 57 is less than that of the upper burner throat 75 distant from the heated object 57, the inside of the furnace 7 spreading in front of the lower burner throat 75. A non-oxidizing atmosphere is formed in the zone Z1, and an oxidizing atmosphere is formed in the zone Z2 inside the furnace 7 that extends in front of the upper burner throat 75.

Combustion air is supplied to each burner throat 75 from a single air supply system, and each orifice 77 is supplied.
The pressures on the upstream side (the heat storage body 9 side) of a and 77b have the same value. Therefore, the combustion air flows at the same speed in the burner throats 75, 75. Therefore, each burner throw and area Z ejected from 75, 75
The combustion gas in the oxygen-deficient state of No. 1 and the combustion gas in the oxygen-excessive state of region Z2 gradually spread in substantially the same manner, contact with each other in region Z3, and undergo afterburning (re-combustion).
Here, the total amount of combustion air supplied by the air supply system is
The total amount of fuel injected from each fuel nozzle 13 is set to an amount that provides an appropriate air ratio. Therefore, the area Z
The combustion gas re-combusted in No. 3 is completely combusted in the furnace 7, and is exhausted through the burner throats 75, 75 of the burner 73 which is not in operation.

Since the burner system 71 of the present embodiment burns a set of burners 73 alternately as in the burner system 1 described above, description of its operation is omitted.

In the air ratio control mechanism 77 of this embodiment, the ratio of the combustion air amount flowing in each burner throat 75 is determined, and the oxygen state of the flame generated in each burner throat 75 is adjusted by this. However, the air ratio control mechanism is not limited to this. For example, a structure that changes the flow rate of the combustion air in each burner throat and 75 while keeping the flow rate constant may be used.

FIG. 7 shows an example of this type of air ratio control mechanism 81, which shows two sets of orifices 83a, 83b, 8
It is composed of a combination of 5a and 85b. The first orifices 83a and 83b are the second orifices 85.
It is arranged on the upstream side (the heat storage body 9 side) of a, 85b. Regarding the first orifice 83, the passage area S1 of the orifice 83a provided in the lower burner throat 75 is
Orifice 83 provided in upper burner throat 75
It is set to be narrower (S1 <S2) than the passage area S2 of b, and the passage area S of the orifice 85a provided in the lower burner throat 75 with respect to the second orifice 85 is set.
3 is set to be wider (S3> S4) than the passage area S4 of the orifice 85b provided in the upper burner throat 75. Then, these first orifices 83
a, 83b and the opening area of the second orifices 85a, 85b, for example, the sum of the reciprocals of the passage areas of the orifices 83a, 85a for the lower burner throat 75 is calculated as follows:
To be equal to the sum of the reciprocals of the passage areas of 3b and 85b, that is, the relational expression (1 / S1) + (1 / S3) = (1 /
By setting so that S2) + (1 / S4) is satisfied, the air flow rate, that is, each burner throat 75,75 is changed without changing the air ratio set in each burner throat 75,75.
It is possible to change the velocity ratio of the gas ejected from.

As a result, the upper burner throat 75
The flame generated in the above-mentioned blows out more vigorously than the flame generated in the lower burner throat 75, and the combustion gas emitted from the lower burst funnel 75 is the upper burner throat 75.
The object to be heated 57 is attracted by the flow of combustion gas ejected from the
The afterburning zone Z3 can be moved in the furnace without changing the atmosphere of the area Z1 around the.

In this embodiment, the orifices 77, 83, 85 are fixed type orifices, but the present invention is not limited to this, and each of the orifices 77, 83, 85 may be a conventionally known variable orifice. However, in this case, the ratio of the flow velocity of the combustion air flowing in each burner throat 75 can be adjusted arbitrarily.

FIG. 8 shows another embodiment of the heat storage type burner system of the present invention. In the burner system of this embodiment, a plurality of burner throats 11, 11, 11, 11 are formed by a plurality of burners 3A1 and 3B1, 3A2 and 3B2 each having an independent combustion air supply system, and each burner 3 is formed.
The burner 3A1 and 3A2 or 3B1 and 3B2 have different air ratios within a range in which the total amount of combustion air and the total amount of fuel supplied to A1 and 3A2 or 3B1 and 3B2 are appropriate air ratios. is there. In particular, the one shown
A burner throat that burns when there is excess air and a burner throat that burns when there is insufficient air are provided, including the case where only combustion air is supplied. When the air ratio becomes uniform as a whole, that is, when the oxidizing atmosphere gas and the non-oxidizing atmosphere gas come into contact with each other, afterburning occurs and only the radiant heat is given to the object 57 to be heated. In this case, the heating efficiency is not deteriorated by applying the heat of complete combustion generated around the atmosphere to the object to be heated 57 with the object to be heated 57 covered with the atmosphere having the specific property.

In addition, each burner throat 11, 11, 1
The burner throats 11 and 11 are installed with their injection axes crossed so that the atmosphere formed by the flames and combustion gases ejected from the burners 1 and 11 intersect at a location apart from the object to be heated 57 in the furnace. An afterburning zone Z3 is formed at a position away from the heated object 57 so as to completely burn it. In this case, the atmosphere formed by combustion with insufficient air, for example, Z1 and the atmosphere formed by combustion with excessive air, such as Z2, are surely mixed in the furnace 7 to cause afterburning and facilitate complete combustion. In the case of this embodiment, the two sets of burner systems have combustion air supply systems independent from each other, but the combustion gases are finally mixed in the furnace 7 to cause complete combustion with an appropriate air ratio as a whole. After that, since the exhaust gas is separated and passed through the burner throat of the burner which becomes a pair of each burner system, each heat storage body 9,
Exhaust gas of substantially the same temperature passes through 9. In the case of this embodiment, since the object to be heated 57 is completely covered with a specific atmosphere without disturbing the atmosphere Z1 around the object to be heated 57, the object to be heated 57 can be reliably contacted with the other atmosphere Z2. The lower burner throat 11 is installed so that the gas is ejected substantially horizontally, and the upper burner throat 11 is tilted so as to eject the gas slightly downward. Further, in this state, as described in FIG. 7, the upper burner throat 11
It is possible to move the position of the afterburning zone Z3 inside the furnace by controlling the flow velocity of the air flowing through.

Next, FIG. 9 will be described. FIG. 9 shows an example in which the burner system 71 according to the present invention is used in combination with two sets of burner systems 91 of another type.

Each burner system 91 is a regenerative burner system having a pair of burners 93 having a single burner throat 95 and alternately operating these to burn. The respective burner systems 91 are arranged side by side vertically, and the same amount of fuel is supplied to them. The amount of combustion air supplied to the lower burner system 91 is set to be smaller than the amount of combustion air supplied to the upper burner system 91. Therefore, the flame generated in the burner throat 95 of the lower burner system 91 burns in an oxygen-deficient state, and the front space is set to a non-oxidizing atmosphere. In addition, the burner throat 95 of the upper burner system 91 burns in an excess oxygen state to set the front space to an oxidizing atmosphere. The total amount of combustion air supplied to each burner system 91 is set to an amount suitable for burning the entire amount of fuel supplied to each burner system 91. Therefore, each burner system 91 implements a rich and lean combustion.

That is, by using the two sets of burner systems 91 in combination, the same effect as the burner system 71 can be obtained. By using the burner system 71 and the two sets of burner systems 91 in combination, the oxygen state of the space around the object 57 to be heated can be adjusted in various ways.

[0074]

As described above, in the heat storage type burner system of the present invention, the exhaust gas and the combustion air are alternately flown through the heat storage body to obtain high temperature combustion air close to the exhaust gas temperature. The burner throat is supplied with a proper air ratio as a whole and a different air ratio for each burner throat, and complete combustion is performed under a proper air ratio as a whole.
The atmosphere formed by the flame and combustion gas generated for each burner throat is designed to be in an oxygen-deficient or oxygen-excessive state. An atmosphere can be created in the furnace. Therefore, it becomes possible to heat the object to be heated in an atmosphere suitable for the object to be heated, and at the same time complete combustion is achieved. Therefore, for example, it is possible to prevent deterioration of quality due to oxidation of the object to be heated. Further, so-called rich and lean combustion can be performed as the overall combustion, and NOx generation can be reduced.

According to the second aspect of the invention, since a single air supply system is sufficient for a plurality of burner throats, the burner facility is simple and the installation space is not required.

Further, in the burner apparatus according to the third aspect, the air ratio control means determines the ratio of the amount of combustion air flowing in each burner throat. Therefore, the air ratio can be adjusted by controlling the ratio of the combustion air flowing into each burner throat from a single air supply source, that is, the air ratio is adjusted while keeping the amount of fuel constant, The effect can be obtained.

Further, in the burner apparatus according to the fourth aspect, the air ratio control means sets the passage areas of the respective burner throats to different values and controls the amount of combustion air flowing in the burner throat. It has a means for increasing and decreasing. Therefore, the air ratio can be adjusted by controlling the passage area of the burner throat, that is, the air ratio can be adjusted while keeping the amount of fuel constant, and the above-mentioned effect can be obtained.

Further, in the burner device according to the fifth aspect, the air ratio control means can relatively adjust the air ratio by setting the amounts of fuel injected from the fuel injection nozzles to different values. As a result, it is only necessary to control the fuel supply system outside the burner throat, which simplifies the burner structure.

In the sixth aspect of the invention, by controlling the amount of combustion air and the amount of fuel distributed for each burner throat, combustion with a desired air ratio can be realized in a more stable state.

Further, according to the invention of claim 7, since the air supply systems are independent from each other, combustion control for each atmosphere is easy.

Further, in the invention of claim 8, the object to be heated can be covered with either a non-oxidizing atmosphere or an oxidizing atmosphere, and the heat due to complete combustion occurring around the atmosphere is radiated, so that the heating efficiency is improved. It is possible to realize heating under a specific atmosphere without dropping.

According to the ninth aspect of the invention, the atmosphere formed by the combustion with insufficient air and the atmosphere formed by the combustion with excessive air are surely mixed in the furnace to cause afterburning. Therefore, the heat storage body does not burn and the heat storage body is not damaged.
Moreover, it occurs outside or around the atmosphere that covers the object to be heated and does not change the atmospheric components around the object to be heated.

Further, in the burner device according to claim 10,
The air ratio control means can adjust the flow velocity of the combustion air in each burner throat. Therefore, it is possible to control the size of the area set in front of each burner throat, and to adjust the size of the area set around it in accordance with the size of the material to be heated in the furnace. it can.

Further, according to the invention of claim 11, it is sufficient to control the combustion for each individual burner system, so that the combustion control is easy.

Further, in the burner system according to the twelfth aspect, the burner devices are arranged in pairs in the furnace and the burner devices are alternately operated to perform the exchange combustion. Therefore, even in a regenerative burner system with good thermal efficiency, the oxygen concentration in the furnace atmosphere can be partially adjusted,
Further, since the light and dark combustion is performed in the entire system, it is possible to suppress the generation of NOx.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a heat storage type burner system of the present invention.

FIG. 2 is a diagram showing details of an air ratio control mechanism applied to the burner system of FIG.

FIG. 3 is a schematic configuration diagram showing an air ratio control mechanism of a burner system to which the present invention is applied and showing another embodiment of the air ratio control mechanism of FIG. 1.

4 is a schematic configuration diagram showing an air ratio control mechanism of a burner system to which the present invention is applied and showing still another embodiment of the air ratio control mechanism of FIG. 3. FIG.

FIG. 5 is a schematic configuration diagram showing a second embodiment of a burner system to which the present invention is applied.

6 is a schematic configuration diagram showing an air ratio control mechanism that constitutes the burner system of FIG.

7 is a schematic configuration diagram showing another embodiment of the air ratio control mechanism of FIG.

FIG. 8 is a schematic configuration diagram showing another embodiment of the heat storage type burner system of the present invention.

FIG. 9 is a perspective view showing an example in which the burner system of FIG. 5 is used in combination with another type of burner system.

FIG. 10 is a schematic configuration diagram of a conventional burner system.

[Explanation of symbols]

 1,71 Burner system 3,73 Burner 5,77,81 Air ratio control mechanism 7 Reactor 9 Heat storage body 11,75 Burner throat 13 Fuel nozzle 17 Air supply system 37 Flow rate adjusting plate 39 Adjusting plate driving means 41 Control switch means 63 Flow rate Control valve

Claims (12)

[Claims] 1. A heat storage body is provided, and the flow of the exhaust gas and the combustion air to the heat storage body is relatively switched to alternately supply the combustion air and discharge the exhaust gas through the heat storage body, and the temperature of the exhaust gas is close to that of the exhaust gas. A plurality of burner throats that supply high-temperature combustion air to burn and eject flames into the furnace are provided.Each burner throat has an air ratio of insufficient air or excess air, and the overall amount of the air ratio is appropriate. Combustion air is supplied to the burner throat and burned at a different air ratio for each burner throat to partially form a plurality of atmospheres with different properties such as oxidizing, weakly oxidizing or non-oxidizing in the furnace. However, the heat storage type burner system is characterized by complete combustion at an appropriate air ratio as a whole. 2. A single air supply system is connected to the plurality of burner throats, and an amount of combustion air having an appropriate air ratio as a whole is distributed and supplied to each burner throat, and each burner throat is supplied. The regenerative burner system according to claim 1, wherein the air ratios are different from each other. 3. The regenerative burner system according to claim 2, wherein the amount of fuel injected for each burner throat is constant and a different amount of combustion air is distributed for each burner throat. . 4. The amount of combustion air flowing in the burner throat is provided with air amount adjusting means that can be independently controlled for each burner throat, and sets the passage areas of the burner throats to different values. 4. The regenerative burner system according to claim 3, wherein the air ratio is changed for each burner throat by controlling the. 5. The air ratio for each burner throat is set by setting the amount of air distributed for each burner throat constant and setting the amounts of fuel injected from the fuel injection nozzles for each burner throat to mutually different values. The heat storage type burner system according to claim 2, wherein 6. The fuel and combustion air supplied to each of the burner throats are controlled for each of the burner throats so that different air ratios can be set for each of the burner throats. The heat storage type burner system described in 2. 7. A range in which a plurality of burner throats are formed by a plurality of burner systems each having an independent air supply system, and the total amount of combustion air and the total amount of fuel supplied to each of the burners have an appropriate air ratio. The heat storage type burner system according to claim 1, wherein each burner has a different air ratio. 8. A burner throat that burns when there is excess air and a burner throat that burns when there is insufficient air are provided, including the case of supplying only combustion air, and either atmosphere is formed around the object to be heated. 7. The regenerative burner according to any one of claims 1 to 6, characterized in that after-burning is caused when the air ratio becomes even more uniform around it, and only the radiant heat is given to the object to be heated. system. 9. The injection axes of the burner throats are installed so as to intersect so that the atmosphere formed by the flames and combustion gases ejected from each burner throat intersects at a location distant from the object to be heated in the furnace. The heat storage type burner system according to any one of claims 1 to 8, wherein an afterburning zone is formed at a position apart from the heated material to complete combustion. 10. The heat storage type burner system according to claim 1, wherein an injection speed of the combustion air distributed to each of the burner throats can be adjusted for each burner throat. 11. A heat storage type burner system for distributing combustion air having a proper air ratio to a plurality of burner throats as a whole to form excess air combustion and insufficient air combustion with one burner, and heat storage for combustion with excess air. Type burner system,
The heat storage type burner system according to claim 1, wherein at least one set or more of the heat storage type burner system which burns due to insufficient air is combined. 12. A burner pair, and the burners are alternately exchange-combusted in a short time in a short time.
The heat storage type burner system according to any one of 1.