JP4132621B2 - Heating furnace burner and structure determination method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heating furnace burner that heats an object to be heated in a furnace by injecting fuel that circulates inside a cylindrical burner nozzle from an ejection port formed at one end of the burner nozzle and burning the fuel. The present invention relates to a method for determining the structure of the furnace burner.
[0002]
[Prior art]
Such a heating furnace burner heats an object to be heated in the furnace directly or indirectly by a combustion gas obtained by burning fuel, and particularly as an indirect heating from the furnace wall side. Combustion gas flow path provided with a cylindrical radiant tube protruding into the furnace, the jet port of the burner nozzle being inserted into the radiant tube from the furnace wall side, and formed inside the radiant tube There is one configured as a radiant tube burner that jets and burns fuel.
In such a heating furnace burner, since the fuel is jetted from the jet nozzle formed at the tip of the burner nozzle and burned, the temperature in the vicinity of the jet nozzle becomes very high. Ni base metals are also used. However, in recent years, with the demand for an increase in the heating temperature of an object to be heated in a furnace, in order to improve the heat resistance of the burner nozzle and make it possible to use it stably for a long period of time, SiC (carbonized) is used as the material of the burner nozzle. The use of ceramics with high heat resistance such as silicon) or Si ₃ N ₄ (silicon nitride) has been studied.
[0003]
[Problems to be solved by the invention]
However, a conventional ceramic burner nozzle needs to be formed so that one end of the burner nozzle can be connected to the fuel pipe in order to supply fuel to the inside, and a fixing part for fixing the burner nozzle needs to be provided. Since the shape is complicated and it is difficult to process the ceramic, it may cause a significant increase in cost and may become impossible.
Further, such a burner nozzle is cantilevered only at the end opposite to the jet nozzle side, and the position of the support part is restricted by the structure of the burner for the heating furnace, so that it is located away from the jet nozzle. In many cases, if the ceramic burner nozzle with low toughness is too long, problems such as breakage of the burner nozzle occur.
[0004]
Therefore, in view of the above circumstances, the present invention simplifies the shape of the burner nozzle in the heating furnace burner as much as possible, suppresses the high cost associated with the ceramicization of the burner nozzle, and prevents breakage of the ceramic. The purpose is to obtain technology that can
[0005]
[Means for Solving the Problems]
[Configuration 1]
The heating furnace burner according to the present invention includes a cylindrical radiant tube protruding into the furnace from the furnace wall side , as described in claim 1, and includes a cylindrical burner nozzle inserted into the radiant tube . A burner for a heating furnace that heats the inside of the furnace by injecting and burning the fuel that circulates inside from a jet port formed at one end of the burner nozzle,
The burner nozzle is made of a ceramic ceramic tube portion having the jet port formed at one end thereof, and the other end portion of the ceramic tube portion is fitted into one end portion with an adhesive, and the other end portion And a metal cylinder portion to which fuel is supplied from,
An inner cylinder is provided between the radiant tube and the burner nozzle,
A combustion gas flow path for flowing a combustion gas is formed between the inner cylinder and the radiant tube, and an oxygen-containing gas flow path for flowing a combustion oxygen-containing gas between the inner cylinder and the burner nozzle. Formed,
The oxygen-containing gas flow path is configured to communicate with an upstream flow path of the combustion oxygen-containing gas that surrounds the combustion gas flow path,
A fitting part obtained by fitting the ceramic cylinder part and the metal cylinder part with the adhesive is arranged so as to overlap the upstream flow path in the axial direction of the radiant tube .
[0006]
[Function and effect]
As in this configuration, in the furnace burner, a ceramic cylinder portion made of ceramic having excellent heat resistance that forms a particularly high temperature jet nozzle at one end, and an end opposite to the jet nozzle of the ceramic cylinder portion By forming a burner nozzle with the metal cylinder part that is fitted and joined with a gap filled with an adhesive at one end, the inside of the metal cylinder part from the end opposite to the fitting part The supplied fuel can be supplied to the inside of the ceramic cylinder part through the inside of the fitting part and ejected from the jet port, and the shape of the fitting part on the ceramic cylinder side is cylindrical. However, because the position of the burner nozzle is maintained by fixing the metal cylinder part outside the furnace wall, for example, there is no need to provide a separate fixing part for the ceramic burner nozzle, and the shape of the burner nozzle is simplified. Yes, Sera High cost due to click of can be suppressed. In addition, when fitting the ceramic cylinder part and the metal cylinder part, by providing a gap and filling the adhesive, the stress generated in the fitting part due to the difference in the coefficient of thermal expansion of different materials is relieved by the elasticity of the adhesive, It is possible to suppress breakage and dropout of the ceramic cylinder.
In addition, the position of the fitting portion can be as close as possible to the spout, and the temperature of the fitting portion can be at or below the allowable temperature of the adhesive. Damage can be suppressed.
Therefore, it is possible to realize a heating furnace burner that can simplify the shape of the ceramic tube portion as much as possible, suppress the high cost associated with the ceramicization of the burner nozzle, and prevent damage to the ceramic.
[0007]
Furthermore, the furnace burner of the present invention, by constituting a so-called radiant tube burner, radiant fuel is ejected into the combustion gas passage formed inside the tube, in particular injection of burner nozzles that around spout becomes high The outlet is formed by a simple-shaped ceramic cylinder portion to improve heat resistance, while suppressing high cost and preventing breakage of ceramic with low toughness.
[0008]
Furthermore, in the heating furnace burner of the present invention configured as a so-called radiant tube burner, as in the present configuration, the cylindrical radiant tube with the end portion inside the furnace sealed, and the radiant tube are inserted into the interior. And an air passage (oxygen-containing gas) formed between the inner cylinder and the burner nozzle. The fuel is ejected from the outlet into the inner cylinder. Combustion is performed using air (oxygen-containing gas) supplied to the ejection port via the flow path), and the combustion gas is discharged from the end of the inner cylinder radiant tube on the sealing portion side to the radiant tube. The radiant tube can be made to flow through a combustion gas flow path formed between the inner cylinder and the outside to be discharged from the end opening on the furnace wall side of the radiant tube. By configuring in this way, only the combustion air preheated from the combustion gas flow path through the inner cylinder flows in the outer peripheral portion of the burner nozzle, so the temperature rise of the burner nozzle is suppressed. The length of the ceramic cylinder part can be shortened by setting the position of the fitting part to be close to the jet nozzle, and it is possible to further suppress the high cost due to the ceramicization and the breakage of the ceramic.
[0009]
Further, the oxygen-containing gas channel is configured to communicate with an upstream channel of the combustion oxygen-containing gas that surrounds the combustion gas channel, and the ceramic cylinder part and the metal cylinder part are bonded together. By disposing the fitting portion fitted with the agent so as to overlap the upstream flow path in the axial direction of the radiant tube, the fitting portion can be set to be equal to or lower than the allowable temperature of the adhesive.
[0010]
[Configuration 2 ]
Furnace burner according to the present invention, as set forth in claim 2, in addition to the furnace burner of the arrangement 1, wherein the adhesive, characterized in that it is a heat-resistant adhesive.
[0011]
[Function and effect]
As in this configuration, it is preferable to use, for example, a heat-resistant adhesive having an allowable temperature of about 600 ° C. as the adhesive, and the length of the ceramic cylinder portion is shortened by making the position of the fitting portion closer to the jet port. Therefore, it is possible to further suppress the high cost due to the ceramicization and the breakage of the ceramic.
Further, as the adhesive having an allowable temperature of 600 ° C., it is most preferable to use a heat-resistant inorganic adhesive using alumina as an aggregate.
[0012]
[Configuration 3 ]
Structure determination method of the heating furnace burner according to the present invention, as set forth in claim 3, a structure determination method of the heating furnace burner as claimed in claim 1,
The position of the fitting portion between the ceramic tube portion of the burner nozzle and the metal tube portion in the fuel flow direction that is the axial direction of the radiant tube is such that the temperature of the fitting portion is equal to or lower than the allowable temperature of the adhesive. Position it as follows.
[0013]
[Function and effect]
In the heating furnace burner according to claim 1, in order to determine the position of the fitting portion, it is preferable that the fitting portion is as close as possible to the ejection port and the length of the ceramic cylinder portion is short. Since the adhesive provided in the fitting portion becomes hot and may be damaged when approaching the jet port that becomes high temperature, the position of the fitting portion in the fuel flow direction that is the axial direction of the radiant tube as in this configuration Is preferably positioned so as to be equal to or lower than the allowable temperature of the adhesive, and the burner for a heating furnace having the structure determined in this way can always maintain a preferable joining state of the fitting portion.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a heating furnace burner according to the present invention will be described with reference to the drawings.
The heating furnace burner shown in FIG. 1 burns fuel gas, which is a natural gas city gas flowing inside the cylindrical burner nozzle 20, from a jet outlet 23 formed at one end of the burner nozzle 20. Specifically, the furnace 10 is heated, and more specifically, a cylindrical radiant tube 1 made of SiC ceramic with the end on the furnace 10 side sealed, and inserted into the radiant tube 1 and a burner nozzle inside. And an air flow path formed between the inner cylinder 7 and the burner nozzle 20 for the fuel gas injected into the inner cylinder 7 from the injection port 23. 2 (an example of an oxygen-containing gas flow path) is combusted by using air (an example of an oxygen-containing gas) supplied to the jet outlet 23 side, and the combustion gas is sealed in the radiant tube 1 of the inner cylinder 1. Stop A radiant tube burner that circulates from the end on the side to a combustion gas flow path 8 formed between the radiant tube 1 and the inner cylinder 7 to heat the radiant tube 1 and indirectly heat the furnace 10. 100. Further, the exhaust gas after heating the radiant tube 1 is discharged from the other end side of the radiant tube 1 and used in the heat exchanger 12 for preheating combustion air.
[0015]
That is, the heat exchanger 12 is fixed to the wall portion 11 with bolts (not shown) with the gasket 17 interposed therebetween, together with the flange portion 1a provided outside the furnace wall 11 of the radiant tube 1 in the flange portion 12a. The Moreover, it has the outer casing 13 provided in the outer side, and the inner casing 14 provided in the inner side, The exhaust gas supplied from the combustion gas flow path 8 of the radiant tube 1 between the inner cylinder 7 and the inner casing 14 Between the inner casing 14 and the outer casing 13, and a flow path 15 that circulates air supplied from the air opening 15 a and supplies the air flow path 2 to the air flow path 2. Has been. In such a heat exchanger 12, the combustion gas flowing through the combustion gas flow path 8 and the flow path 16 causes the combustion air flowing through the flow path 15 and the air flow path 22 to pass through the inner casing 14 and the inner cylinder 7. Can be preheated.
Further, the burner nozzle 20 has an end portion fixed to the outer casing 13 of the heat exchanger 12, and the fixed portion is configured as a fuel gas supply portion 26 to which fuel gas is supplied.
[0016]
The above configuration is a general configuration of the radiant tube burner 100. Next, the characteristic configuration of the present invention will be described.
Such a burner nozzle 20 of the radiant tube burner 100 has been considered to be made into ceramics in response to a recent increase in heating temperature. However, due to the strength of ceramics and difficulty in processing, the burner nozzle 20 is entirely made of ceramic. It is difficult to do.
Therefore, as shown in FIG. 2, the burner nozzle 20 of the radiant tube burner 100 according to the present invention includes a ceramic cylinder portion 21 made of SiC ceramic in which a jet port 23 is formed at one end portion, and a fuel gas from a fuel supply portion 26. The metal tube portion 22 made of heat-resistant stainless steel is supplied with a gap of about 0.5 to 1 mm at the fitting portion 24 and the ceramic tube portion 21 is fitted inside, and the gap is filled with the heat-resistant adhesive 25. Thus, the shape of the ceramic cylinder portion 21 can be simplified as much as possible to suppress the cost increase associated with the ceramicization of the burner nozzle 20 and to prevent breakage of the ceramic. Further, the reason that the ceramic cylinder portion 21 is set inside in the fitting portion 24 is that the metal cylinder portion 22 has a larger coefficient of thermal expansion than the ceramic cylinder portion 21 and the ceramic cylinder portion 21 is not damaged by the temperature rise of the fitting portion 24. is there.
[0017]
In order to determine the position of the fitting portion 25, it is preferable that the fitting portion 25 is as close as possible to the jet outlet 23 and the length of the ceramic cylinder portion 21 is short. When approaching the outlet 23, the heat resistant adhesive 25 provided in the fitting portion 24 may be damaged due to a rise in temperature, so the position of the fitting portion 24 in the fuel gas flow direction is less than the allowable temperature of the heat resistant adhesive 25. Specifically, when the thickness of the furnace wall 11 is 300 mm and the outlet 23 of the burner nozzle 20 is located on the wall surface on the furnace wall 10 side of the furnace wall 11, The joining state of the fitting part 24 can always be maintained at a preferable level with the position being about 500 mm from the jet outlet 23 side.
Further, as shown in FIG. 3, the shear strength of the heat-resistant adhesive 25 depends on the temperature and decreases as the temperature increases. For example, the rate of decrease rapidly increases from about 600 ° C. The allowable temperature is preferably not higher than the temperature at which the shear strength rapidly decreases, that is, 600 ° C. or lower, and more preferably 500 ° C. or lower with a margin.
[0018]
[Another embodiment]
Next, another embodiment of the present invention will be described with reference to the drawings.
<1> In the embodiment above SL, the ceramic tube of the burner nozzles has been a SiC ceramic high strength, separately, it may be utilized oxide ceramic such as Si ₃ N ₄ or Al ₂ O3 Absent.
[0019]
< 2 > In the fitting part 24 of the burner nozzle 20 of the above-described embodiment, the metal cylinder part 22 is fitted on the outside and the ceramic cylinder part 21 is fitted on the inside. The part 21 may be fitted outside, and in this case, the gap filled with the adhesive 25 is reduced by increasing the temperature of the fitting part 24. Therefore, it is preferable to set the gap with a large margin.
[0020]
< 3 > In the above embodiment, the configuration in which the combustion gas that is a natural gas city gas is used as the fuel has been described. However, other fuels can be used, for example, kerosene, heavy oil, LPG, or the like as fuel. Can be used as
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating a configuration of a radiant tube burner as an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view illustrating a configuration of a burner nozzle of the radiant tube burner of FIG. Graph showing the relationship between temperature and temperature [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Radiant tube 2 Air flow path 7 Inner cylinder 8 Combustion gas flow path 10 In-furnace 11 Furnace wall 12 Heat exchanger 20 Burner nozzle 21 Ceramic cylinder part 22 Metal cylinder part 23 Jet outlet 24 Fitting part 25 Adhesive 26 Fuel gas supply part 100 Radiant tube burner (heating furnace burner)

Claims (3)

A cylindrical radiant tube that protrudes into the furnace from the furnace wall side is provided, and fuel that flows through the inside of the cylindrical burner nozzle inserted into the radiant tube is formed at one end of the burner nozzle. A heating furnace burner that heats the inside of a furnace by being jetted from a jet outlet,
The burner nozzle is made of a ceramic ceramic tube portion having the jet port formed at one end thereof, and the other end portion of the ceramic tube portion is fitted into one end portion with an adhesive, and the other end portion And a metal cylinder portion to which fuel is supplied from,
An inner cylinder is provided between the radiant tube and the burner nozzle,
A combustion gas flow path for flowing a combustion gas is formed between the inner cylinder and the radiant tube, and an oxygen-containing gas flow path for flowing a combustion oxygen-containing gas between the inner cylinder and the burner nozzle. Formed,
The oxygen-containing gas flow path is configured to communicate with an upstream flow path of the combustion oxygen-containing gas that surrounds the combustion gas flow path,
A heating furnace burner in which a fitting portion obtained by fitting the ceramic tube portion and the metal tube portion with the adhesive is disposed so as to overlap the upstream flow path in the axial direction of the radiant tube . The furnace burner according to claim 1, wherein the adhesive is a heat-resistant adhesive. A method for determining the structure of a furnace burner according to claim 1 ,
The position of the fitting portion between the ceramic tube portion of the burner nozzle and the metal tube portion in the fuel flow direction that is the axial direction of the radiant tube is such that the temperature of the fitting portion is equal to or lower than the allowable temperature of the adhesive. The structure determination method of the furnace burner positioned as follows.

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