JP5202594B2 - Regenerative combustion apparatus and heating furnace - Google Patents

Description

  According to the present invention, combustion air guided to a combustion air supply unit through a heat storage unit in which a heat storage material is accommodated is jetted from an air jet into a heating furnace, and fuel guided through the fuel supply unit is injected into a fuel jet The present invention relates to a regenerative combustion apparatus that jets fuel from the inside into a heating furnace and burns fuel in the heating furnace, and a heating furnace using such a regenerative combustion apparatus. In particular, in the above-described regenerative combustion apparatus, when the fuel is combusted in the heating furnace as described above, the combustion is appropriately performed near the inner wall of the heating furnace provided with the air ejection port and the fuel ejection port. And is characterized by suppressing the generation of NOx during combustion.

  Conventionally, in a heating furnace, in order to perform efficient combustion using the heat of the combustion exhaust gas, the combustion exhaust gas in the heating furnace is discharged through a heat storage part in which a heat storage material is stored during non-combustion, and combustion While storing the heat of the exhaust gas in the heat storage material, at the time of combustion, the combustion air is heated through the heat storage section in which the heat storage material thus stored is accommodated, and the combustion air thus heated is used as the combustion air. A regenerative combustion apparatus is used in which a fuel is burned by being jetted from an air jet through a supply section into a heating furnace.

  Here, as the heat storage type combustion device, for example, as shown in Patent Document 1 and the like, the combustion air heated through the heat storage unit that stores the heat of the combustion exhaust gas is guided from the air introduction unit to the mixing chamber, The fuel is guided to the mixing chamber through the fuel supply nozzle, and the heated combustion air and the fuel are mixed in the mixing chamber, and the fuel is introduced from the mixing chamber to the combustion chamber on the furnace side to be burned. As shown in Patent Documents 2 and 3, etc., primary fuel is supplied from a primary fuel nozzle to a combustion air supply unit that guides combustion air heated in a heat storage unit that stores heat of combustion exhaust gas. And a secondary fuel outlet for injecting secondary fuel into the heating furnace around the air outlet for injecting combustion air from the combustion air supply unit into the heating furnace. Secondary fuel jet Secondary fuel is ejected into the heating furnace from are widely those so as to secondary combustion in the furnace the secondary fuels.

  However, as shown in Patent Document 1 and the like, when an air-fuel mixture in which heated combustion air and fuel are mixed is burned in the combustion chamber, the combustion temperature in the combustion chamber becomes high, and NOx is generated. There was a problem of increasing.

  Further, as shown in Patent Documents 2 and 3, etc., the primary fuel is supplied from the primary fuel nozzle to the combustion air supply unit that guides the heated combustion air, and the primary combustion is performed. Air is ejected from the combustion air supply unit into the heating furnace through the air ejection port, and secondary fuel is ejected from the secondary fuel ejection port provided around the air ejection port into the heating furnace. Even when the fuel is subjected to secondary combustion in the heating furnace, the secondary fuel injected from the secondary fuel injection port into the heating furnace immediately comes into contact with the combustion air injected from the air injection port. When combusted, the combustion temperature in this part becomes high and the generation of NOx still increases.

  For this reason, conventionally, the secondary fuel jet port is provided at a position away from the air jet port, or the combustion air flow rate that is jetted from the air jet port into the heating furnace is increased. It has been proposed that the production air and the secondary fuel are gradually brought into contact with each other at a position away from the air outlet or the secondary fuel outlet and burned to suppress the generation of NOx.

  However, when the combustion air and the secondary fuel are gradually brought into contact with each other at a position away from the air outlet or the secondary fuel outlet and burned, the air outlet and the secondary fuel outlet are The temperature in the heating furnace in the vicinity of the provided inner wall is not sufficiently increased, resulting in uneven temperature in the heating furnace, and the object to be processed cannot be properly heated, or the secondary fuel is not enough. The remaining secondary fuel that is not combusted is led to the heat storage section in other heat storage combustion devices together with the combustion exhaust gas, and the combustion efficiency is reduced, or the secondary fuel is guided in this way. There is a problem that combustion is performed in the heat storage part of the heat storage type combustion apparatus and the heat storage material in the heat storage part is overheated.

JP 2002-139217 A Japanese Patent No. 3031908 Japanese Patent No. 3557028

  According to the present invention, combustion air guided to a combustion air supply unit through a heat storage unit in which a heat storage material is accommodated is jetted from an air jet into a heating furnace, and fuel guided through the fuel supply unit is injected into a fuel jet It is an object of the present invention to solve the above-mentioned problems in a regenerative combustion apparatus that injects fuel into a heating furnace and burns fuel in the heating furnace and a heating furnace using such a regenerative combustion apparatus. is there.

  That is, according to the present invention, in the regenerative combustion apparatus as described above, when the fuel is burned in the heating furnace, the combustion is appropriately performed even near the inner wall of the heating furnace provided with the air outlet and the fuel outlet. The temperature in the vicinity of the inner wall of the heating furnace is also sufficiently increased to prevent temperature unevenness in the heating furnace, to ensure that the workpiece is properly heat-treated, and the fuel is sufficiently Prevents combustion efficiency from being reduced by preventing the combustion exhaust gas from being introduced together with the combustion exhaust gas to the heat storage unit in other heat storage combustion devices, and is stored in the heat storage unit in other heat storage combustion devices. It is an object to prevent the heat storage material from overheating and to suppress the generation of NOx during combustion.

  In the regenerative combustion apparatus according to the present invention, in order to solve the above-described problems, the combustion air guided to the combustion air supply unit through the heat storage unit in which the heat storage material is accommodated is introduced from the air outlet into the heating furnace. In the regenerative combustion apparatus in which the fuel guided through the fuel supply unit is ejected from the fuel ejection port into the heating furnace and the fuel is combusted in the heating furnace, the air ejection port and the fuel ejection port are In addition to being provided at a required interval, an inclined portion inclined so as to be tapered toward the inside of the heating furnace was provided at a portion of the air outlet in the combustion air supply portion.

  Here, in the regenerative combustion apparatus according to the present invention, it is preferable that the inclination angle θ of the inclined portion inclined so as to spread in a tapered shape toward the heating furnace is in a range of 1 ° to 3.5 °.

  Further, in the regenerative combustion apparatus according to the present invention, the diameter Da before the combustion air supply section expands in a taper shape, and the straight line from the tilt start position to the air jet outlet in the taper inclined section. The shortest distance X preferably satisfies the condition of 0.5 ≦ X / Da ≦ 2.0.

  Further, in the regenerative combustion apparatus according to the present invention, the distance Da between the portion before the combustion air supply section expands in a taper shape and the center of the air outlet and the center of the fuel outlet L preferably satisfies the condition of 0.25 ≦ Da / L ≦ 0.30.

  Furthermore, in the regenerative combustion apparatus according to the present invention, an inclined portion that is inclined so as to spread in a tapered shape toward the inside of the heating furnace can be provided also in the portion of the fuel outlet that ejects the fuel into the heating furnace.

  And in the heating furnace in this invention, it was made to use the above heat storage type combustion apparatuses.

  Like the regenerative combustion apparatus of the present invention, the air outlet and the fuel outlet are provided at a required interval, and the air outlet in the combustion air supply section is tapered toward the inside of the heating furnace. By providing an inclined portion that is inclined so as to spread, the combustion air guided to the combustion air supply section through the heat storage section in which the heat storage material is accommodated is ejected from the air outlet into the heating furnace and is also guided through the fuel supply section. When the injected fuel is jetted from the fuel jet into the heating furnace, and the fuel is burned in the heating furnace, the combustion air jetted from the air jet is along an inclined portion inclined so as to spread in a taper shape. The combustion air blown out in the heating furnace is brought into contact with the fuel blown out from the fuel jet outlet and burned, and the air jet outlet and the fuel jet outlet are burned. Also in the vicinity of the inner wall of the furnace provided with proper combustion is performed, so that temperature increases.

  As a result, in a heating furnace using such a regenerative combustion apparatus, temperature unevenness is prevented from occurring in the heating furnace, and the object to be processed is appropriately heated, and the fuel is sufficient. In the state where it is not combusted, it is prevented from being led together with the combustion exhaust gas to the heat storage part in the other heat storage type combustion apparatus, the combustion efficiency is lowered, or the heat storage material accommodated in the heat storage part in the other heat storage type combustion apparatus is Overheating is prevented.

  Further, as described above, the combustion air ejected from the air ejection port is ejected so as to spread in the heating furnace along the inclined portion inclined so as to spread in a taper shape. The air is mixed with the combustion exhaust gas in the heating furnace and the oxygen concentration in the combustion air is reduced. The combustion air thus reduced in oxygen concentration spreads over a wide angle and is heated with the fuel ejected from the fuel outlet. Combustion is performed in contact with a position close to the inner wall of the furnace, so that the combustion temperature at the time of combustion is prevented from rapidly rising, and generation of NOx is also suppressed.

  As a result, in the heating furnace of the present invention, an inclined portion that is inclined so as to expand in a tapered shape toward the inside of the heating furnace is provided at the air outlet, so that combustion is also performed in the vicinity of the inner wall of the heating furnace. The temperature rises uniformly to every corner of the furnace, and the generation of NOx is suppressed.

It is a partial explanatory view of a heating furnace using a regenerative combustion device according to an embodiment of the present invention. In the regenerative combustion apparatus according to the above-described embodiment, it is a schematic explanatory view showing a state in which an inclined portion that is inclined so as to spread in a tapered shape toward the heating furnace is provided at the air outlet. It is a schematic explanatory drawing of the thermal storage type combustion apparatus which concerns on the reference example in which the part of the air jet nozzle is linear, and the inclination part inclined so that it may taper-out toward a heating furnace is not provided. It is the figure which showed the relationship between inclination-angle (theta) in the inclination part of an air jet nozzle, and the oxygen concentration in the combustion air in the intersection position P where combustion air and a fuel contact. In the regenerative combustion apparatus according to the above-described embodiment, a state in which an inclined portion that is inclined so as to expand in a tapered shape toward the inside of the heating furnace is also provided in the portion of the fuel outlet that ejects fuel into the heating furnace is shown. FIG.

  Hereinafter, a regenerative combustion apparatus according to an embodiment of the present invention and a heating furnace using the regenerative combustion apparatus will be specifically described with reference to the accompanying drawings. In addition, the regenerative combustion apparatus and the heating furnace according to the present invention are not limited to those shown in the following embodiments, and can be appropriately modified and implemented within a range not changing the gist of the invention.

  In this embodiment, as shown in FIG. 1, a pair of regenerative combustion apparatuses 10 are provided to face the inside of the heating furnace 1.

  Here, when combustion is performed in the heat storage type combustion device 10, the combustion air is guided to the heat storage unit 12 in which the heat storage material 11 is accommodated, and the combustion air is heated in the heat storage unit 12. To do. The combustion air thus heated is ejected from the heat accumulating section 12 through the combustion air supply section 13 into the heating furnace 1 through the air outlet 14 provided at the tip thereof, and a gas supply pipe (fuel supply section). ) The fuel guided through 15 is jetted into the heating furnace 1 from the fuel jet port 16, and the fuel jetted in this way is brought into contact with the combustion air jetted from the air jet port 14 in the heating furnace 1. I try to let them.

  On the other hand, in the regenerative combustion apparatus 10 that does not perform combustion, the fuel is stopped from being guided to the fuel outlet 16 through the gas supply pipe 15 and the combustion exhaust gas in the heating furnace 1 is sucked and exhausted through the heat storage section 12. The heat of the combustion exhaust gas is stored in the heat storage material 11 accommodated in the heat storage section 12.

  And in the thermal storage type combustion apparatus 10 of this embodiment, as shown in FIG.1 and FIG.2, while providing the air injection port 14 and the fuel injection port 16 via a required space | interval, said combustion air supply part 13 is provided with an inclined portion 13a that is inclined so as to expand toward the heating furnace 1 in a tapered shape.

  In this way, when the inclined portion 13a inclined so as to be tapered toward the heating furnace 1 is provided in the portion of the air jet port 14 in the combustion air supply unit 13, the combustion air jetted from the air jet port 14 Is ejected so as to spread in the heating furnace 1 along the inclined portion 13a inclined so as to spread in a tapered shape.

  The combustion air thus spread and ejected is mixed with the combustion exhaust gas in the heating furnace 10 and the oxygen concentration in the combustion air is reduced. Thus, the combustion air having the reduced oxygen concentration has a wide angle. And the fuel jetted from the fuel jet port 16 comes into contact with the fuel at the intersection P near the inner wall 1a of the heating furnace 1 and combustion is performed. As shown in FIG. 3, an inclined portion is provided. Compared to the intersection position P ′ where the combustion air is ejected linearly from the straight air ejection port 14 ′ and brought into contact with the fuel ejected from the fuel ejection port 16 ′, the intersection position P described above. Is close to the inner wall 1a of the heating furnace 1, and combustion is appropriately performed even near the inner wall 1a of the heating furnace 1 provided with the air jet port 14 and the fuel jet port 16.

  As a result, the temperature is appropriately raised near the inner wall 1a of the heating furnace 1 to prevent temperature unevenness in the heating furnace 1, and the object to be processed (not shown) is appropriately heat-treated. At the same time, it is prevented that the fuel is not sufficiently burned and is led to the heat storage unit 12 in the other heat storage combustion device 10 together with the combustion exhaust gas, so that the combustion efficiency is lowered or the other heat storage combustion device 10 is reduced. This prevents the heat storage material 11 accommodated in the heat storage section 12 from overheating.

  Further, the combustion air ejected from the air ejection port 14 as described above is expelled so as to spread in the heating furnace 1 along the inclined portion 13a inclined so as to spread in a tapered shape. Is rapidly mixed with the combustion exhaust gas in the heating furnace 1 and the oxygen concentration in the combustion air is lowered. For example, as shown in FIG. 4, the inclination angle θ at the inclined portion 13 a of the air outlet 14 is large. Accordingly, the oxygen concentration in the combustion air at the intersection point P where the combustion air and the fuel come into contact with each other decreases, and the combustion air in which the oxygen concentration has thus decreased is ejected from the fuel outlet 16. Coming in contact with the.

  Since combustion is performed by the combustion air having a reduced oxygen concentration, the reaction heat per volume is reduced, and the fuel comes into contact with the combustion air near the inner wall 1a of the heating furnace 1 as described above. In spite of being burned, the combustion temperature at the time of combustion is prevented from rapidly rising, and the generation of NOx is also suppressed.

  Here, when the inclined portion 13a inclined so as to expand in a tapered shape toward the heating furnace 1 is provided at the portion of the air outlet 14 in the combustion air supply portion 13, when the inclination angle θ decreases, the air outlet The combustion air ejected from the furnace 14 into the heating furnace 1 is less spread, making it difficult to obtain the above-mentioned effects sufficiently. The air for use is separated from the inclined portion 13a to generate a vortex or the like, and the combustion air is not properly guided to the air outlet 14 along the inclined portion 13a and is ejected from the air outlet 14 into the heating furnace 1. The spread of combustion air becomes worse, and it becomes difficult to obtain the above effects sufficiently. For this reason, it is preferable to make inclination-angle (theta) in said inclination part 13a into the range of 1 degree-3.5 degrees.

  Further, in providing the inclined portion 13a inclined so as to spread in a tapered shape as described above, if the length of the inclined portion 13a is short, the combustion air is guided to the air outlet 14 along the inclined portion 13a. Therefore, the combustion air ejected from the air ejection port 14 is not ejected in a properly spread state. On the other hand, when the length of the inclined portion 13a is increased, the combustion air is easily separated from the inclined portion 13a, and the size of the apparatus is increased. For this reason, the diameter Da of the combustion air supply unit 13 in the portion before expanding in the taper shape, and the straight shortest distance X from the inclination start position to the air outlet 14 in the inclined portion 13a expanding in the taper shape are 0. It is preferable to satisfy the condition of 5 ≦ X / Da ≦ 2.0.

  Further, when the air jet port 14 and the fuel jet port 16 are provided at a required interval as described above, if the distance between the air jet port 14 and the fuel jet port 16 becomes too small, the air jet port 14 is ejected. Combustion is performed in a state in which the combustion air does not sufficiently spread and comes into contact with the fuel ejected from the fuel jet port 16 and the oxygen concentration in the combustion air is not appropriately reduced by mixing with the combustion exhaust gas. As a result, the combustion temperature rises and NOx is likely to be generated. On the other hand, if the distance between the air jet port 14 and the fuel jet port 16 becomes too large, the combustion air jetted from the air jet port 14 and the fuel jetted from the fuel jet port 16 are not properly brought into contact with each other. Combustion is performed at a position away from the inner wall 1a of the heating furnace 1, and temperature unevenness due to combustion occurs in the heating furnace 1 or other heat storage type together with the combustion exhaust gas in a state where the fuel is not sufficiently combusted. It is guided to the heat storage unit 12 in the combustion device 10. For this reason, the diameter Da before the combustion air supply portion 13 spreads out in a tapered shape and the distance L between the center of the air jet 14 and the center of the fuel jet 16 are 0.25 ≦ It is preferable to satisfy the condition of Da / L ≦ 0.30.

  In the regenerative combustion apparatus 10 of this embodiment, an example in which combustion air is primarily burned is not shown, but a primary fuel supply pipe (not shown) that supplies primary fuel to the combustion air supply unit 13 is not shown. ) And a pilot burner (not shown), and the combustion air guided through the combustion air supply unit 13 can be primarily burned.

  Further, as shown in FIG. 5, an inclined portion 16 a that is inclined so as to spread in a tapered shape toward the inside of the heating furnace 1 is provided also in the portion of the fuel jet port 16, similarly to the air jet port 14. It can also be done. When the inclined portion 16a inclined so as to expand in a tapered shape toward the inside of the heating furnace 1 is also provided in the portion of the fuel jet port 16 as described above, the fuel ejected from the fuel jet port 16 is inclined as described above. It is ejected so as to spread in the heating furnace 1 along the part 16a, and contacts the combustion air ejected so as to spread in the heating furnace 1 from the air jet port 14 along the inclined part 13a as described above. The intersection position P further approaches the inner wall 1 a of the heating furnace 1, and combustion is appropriately performed at a position closer to the inner wall 1 a of the heating furnace 1.

DESCRIPTION OF SYMBOLS 1 Heating furnace 1a Inner wall 10 Thermal storage combustion apparatus 11 Thermal storage material 12 Thermal storage part 13 Combustion air supply part 13a Inclination part 14 Air outlet 15 Gas supply pipe (fuel supply part)
16 Fuel outlet 16a Inclined portion θ Inclined angle of inclined portion Da Diameter of the portion before the combustion air supply portion expands in a taper shape X The shortest straight line distance from the inclination start position to the air outlet in the inclined portion L The air outlet Distance between the center and the center of the fuel jet P Intersection position where the combustion air jetted from the air jet and the fuel jetted from the fuel jet contact

Claims (7)

  The combustion air guided to the combustion air supply unit through the heat storage unit containing the heat storage material is ejected from the air jet into the heating furnace, and the fuel guided through the fuel supply unit is injected from the fuel jet into the heating furnace. In the regenerative combustion apparatus in which the fuel is burned in the heating furnace, the air jet port and the fuel jet port are provided at a required interval, and the air jet port in the combustion air supply unit is provided. A regenerative combustion apparatus characterized in that an inclined portion that is inclined so as to spread in a tapered shape toward the inside of the heating furnace is provided at a portion. Combustion air jetted into the heating furnace from the center of the air jet and the fuel jetted into the heating furnace from the central of the fuel jet are parallel to each other The regenerative combustion apparatus according to claim 1. The regenerative type according to claim 1 or 2 , wherein an inclination angle θ of the inclined portion inclined so as to spread in a tapered shape toward the heating furnace is in a range of 1 ° to 3.5 °. Combustion device. A diameter Da in a portion before the combustion air supply portion expands in a tapered shape and a straight line shortest distance X from the inclination start position to the air outlet in the inclined portion in the tapered shape are 0.5 ≦ X / The regenerative combustion apparatus according to any one of claims 1 to 3, wherein a condition of Da≤2.0 is satisfied. The diameter Da in the portion before the combustion air supply portion expands in a taper shape and the distance L between the center of the air jet port and the center of the fuel jet port are 0.25 ≦ Da / L ≦ The regenerative combustion apparatus according to any one of claims 1 to 4 , wherein a condition of 0.30 is satisfied. The portion of the fuel injection holes for jetting fuel into the furnace, any one of claims 1 to 5, characterized in that a slope portion inclined so as to spread in a tapered shape toward the heating furnace 1 The regenerative combustion apparatus described in the item. A heating furnace using the regenerative combustion apparatus according to any one of claims 1 to 6 .

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