JP5370465B2 - Long flame burner and radiant tube heating device - Google Patents

Description

  The present invention relates to a long flame burner and a radiant tube heating device equipped with the burner.

  As a burner attached to a furnace or a combustor, a nozzle mix type non-premixed long flame burner (for example, patent document) provided with a nozzle for blowing a fuel-containing gas into a combustion chamber and a nozzle for blowing an oxygen-containing gas into the combustion chamber. 1) and a swirling non-premixed long flame burner (for example, Patent Document 2) having swirl vanes for swirling oxygen-containing gas supplied to a combustion chamber are known. Moreover, the radiant tube type heating apparatus (for example, patent document 3) which mounts such a long flame burner is disclosed.

JP-A-4-365812 Japanese Utility Model Publication No.59-139735 Japanese Patent Laid-Open No. 2-103303

  However, the conventional long flame burner described in Patent Documents 1 to 3 and the like, and the radiant tube heating device equipped with the long flame burner have the following technical problems.

  First, there are the following technical problems with the conventional long flame burner.

  (1) There is a case where misfire occurs due to a rapid flow rate fluctuation on the supply side of the fuel-containing gas and the oxygen-containing gas. The main reason is that in order to suppress the mixing of the fuel-containing gas and the oxygen-containing gas, the recirculation region useful for flame holding is limited to a narrow range, and the flame tends to become unstable. In addition, when a practical burner is assumed, the average superficial velocity in the burner is much higher than the laminar combustion velocity, and it is easy to blow out.

  (2) Hard to ignite. The main reason is that a recirculation region suitable for ignition is limited to a narrow range in order to form a long flame. Further, the proper ignition position varies depending on the operating conditions (flow rates of fuel-containing gas and oxygen-containing gas, blowing speed, excess air ratio, etc.).

  Furthermore, the radiant tube type heating device equipped with the conventional long flame burner has the following technical problems.

  (3) Since the combustion chamber (radiant tube) is elongated, the ultimate pressure increases due to abnormal combustion (flame propagation), and the tube (radiant tube) may be damaged.

  (4) Since a secondary flow is formed in the curved pipe portion of the radiant tube, mixing of fuel and oxidant proceeds rapidly here, and a flame is formed to the vicinity of the inner wall. A part may be formed and burning trouble may occur.

  (5) In order to ensure the stability of the flame in the combustion chamber, it is necessary to always operate a pilot burner having a large heat capacity. As a result, the consumption of auxiliary fuel increases.

  (6) Since the combustion chamber is elongated and the wall is red-hot, it is difficult for the conventional misfire detector to detect misfire, the valve fully closing operation after misfire is delayed, and there is a risk of abnormal combustion (deflagration).

  (7) Since the combustion chamber is elongated, the rate at which the combustion reaction is frozen in the vicinity of the inner wall is high, and as a result, the exhaust concentration of unburned gas components and particulate matter increases.

  The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a long flame burner having high safety and reliability and a radiant tube heating device equipped with the burner. is there.

  In order to solve the above problems, the present invention has the following features.

[1] A nozzle mix burner provided with a nozzle for blowing fuel-containing gas into the combustion chamber and a nozzle for blowing oxygen-containing gas into the combustion chamber, or swirl for adding swirl to the oxygen-containing gas supplied to the combustion chamber In the non-premixed long flame burner consisting of any one of the swirl type burners with blades,
Flow rate fluctuation mitigating means for mitigating rapid flow rate fluctuations of the supplied fuel-containing gas or oxygen-containing gas, and a rod-shaped body having a circular cross section tapered downstream from the rear end of the combustion chamber into the combustion chamber And a rod-shaped body heating means for maintaining the temperature of the outer surface of the rod-shaped body at or above the ignition temperature of the fuel.

  [2] The long flame burner according to [1], wherein the rod-shaped body has an uneven surface.

  [3] The rod-like body according to the above [1] or [1], wherein an axial length of a portion inserted into the combustion chamber is within a range of 2 to 10 times an inner diameter of the combustion chamber. 2] The long flame burner described in [2].

  [4] The long flame burner according to any one of [1] to [3], wherein a heat source of the rod-shaped body heating means is a burner or an electric heater.

  [5] When the heat source of the rod-shaped body heating means is a burner, the combustion exhaust gas of the burner is used as a drive gas for an ejector for recirculating the combustion exhaust gas of the long flame burner. The long flame burner according to [4].

  [6] The long flame burner according to any one of [1] to [5], wherein the oxygen-containing gas is preheated by the combustion exhaust gas of the long flame burner.

  [7] The fuel according to any one of [1] to [6], wherein the fuel-containing gas and / or the oxygen-containing gas contains combustion exhaust gas from a long flame burner. Flame burner.

  [8] A radiant tube heating device, wherein the long flame burner according to any one of [1] to [7] is disposed at one or both ends of a radiant tube.

  [9] The radiant tube heating device according to [8], wherein when the long flame burner is disposed at both ends of the radiant tube, the long flame burner is configured to alternately burn.

  [10] The radiant tube heating device according to [8] or [9] above, wherein an inner diameter of the bent tube portion of the radiant tube is smaller than that of the straight tube portion.

  [11] An automatic operation control device is provided for automatically detecting a differential pressure at both ends of the radiant tube and / or an abnormality in the combustion exhaust gas temperature and automatically performing operations from purging with an inert gas to restarting operation. The radiant tube heating device according to any one of [8] to [10], wherein

  In the present invention, a long flame burner and a radiant tube heating device having high safety and reliability can be obtained.

It is a figure which shows the long flame burner which concerns on the 1st Embodiment of this invention. It is a figure which shows the long flame burner which concerns on the 2nd Embodiment of this invention. It is a figure which shows the case where a burner is used as a flame holding rod heating means. It is a figure which shows utilization of the waste gas at the time of using a burner as a flame holding rod heating means. In the long flame burner which concerns on embodiment of this invention, it is a figure which shows having preheated oxygen-containing gas with the waste gas of a long flame burner. It is a figure which shows the radiant tube type heating apparatus provided with the long flame burner which concerns on embodiment of this invention at one end. It is a figure which shows the radiant tube type heating apparatus provided with the long flame burner which concerns on embodiment of this invention at both ends. It is a figure which shows an example of the radiant tube in embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings.

  A long flame burner according to a first embodiment of the present invention is shown in FIG. Fig.1 (a) is a longitudinal cross-sectional view, FIG.1 (b) is an AA arrow line view in Fig.1 (a).

  As shown in FIG. 1, the long flame burner 1 according to this embodiment is a nozzle mix type long flame burner, which has a combustion chamber 11 having an open end 11a, and contains a fuel containing a fuel containing gas (fuel gas). A gas nozzle 12 and an oxygen-containing gas nozzle 13 for blowing oxygen-containing gas (air) are separately provided on the rear end 11 b side of the combustion chamber 11. As a result, a swirling long flame 14 is formed in the combustion chamber 11.

  In the long flame burner 1, a flow rate fluctuation reducing means 31 for reducing a rapid flow rate fluctuation of the fuel-containing gas is installed in a pipe for supplying the fuel-containing gas to the fuel-containing gas nozzle 12. A flow rate fluctuation mitigating means 41 for mitigating a rapid flow rate fluctuation of the oxygen-containing gas is installed in a pipe that supplies the oxygen-containing gas to the nozzle 13. As the flow rate fluctuation mitigating means 31, 41, a buffer tank, a throttle, a filter (a membrane, a packed bed) or the like is used. 1, 32 and 42 are flow meters, 34 and 43 are flow rate adjusting valves, 34 and 44 are check valves, and 35 and 45 are on-off valves. Here, when a mass flow meter is used as the flow meters 32 and 42, the mass flow meter also has a flow rate fluctuation mitigation function, so that a buffer tank, a throttle, a filter, etc. as the flow rate fluctuation mitigation means 31 and 41 are not installed. Also good.

  Thus, since the long flame burner 1 is provided with the flow rate fluctuation mitigating means 31 and 41, the rapid flow rate fluctuation of the fuel-containing gas or the oxygen-containing gas is mitigated, so misfire is avoided, Abnormal combustion is prevented and safety and reliability are improved. In addition, the operating rate is improved and the repair cost is reduced, so the operating cost is reduced.

  Further, in the long flame burner 1, a rod-shaped body (here, a hollow truncated cone-shaped rod body) 21 having a circular cross section inserted concentrically into the combustion chamber 11 from the rear end 11b of the combustion chamber 11, and its A rod-shaped body heating means (in this case, an electric heater) 24 for maintaining the temperature of the outer surface of the rod-shaped body 21 at or above the ignition temperature of the fuel is provided. A thermocouple 23 is attached to the rod-shaped body 21, and the heater controller 24 adjusts the amount of heat input by the electric heater 22 based on the temperature measurement result by the thermocouple 23.

  Thus, in this long flame burner 1, the rod-shaped body 21 is installed concentrically in the combustion chamber 11 from the rear end 11b of the combustion chamber 11, and the temperature of the outer surface of the rod-shaped body 21 is equal to or higher than the ignition temperature of the fuel. Therefore, even if a large flow rate fluctuation occurs for some reason regardless of the operation of the flow rate fluctuation mitigating means 31, 41, the rod-like body 21 in which the surface temperature above the ignition temperature of the fuel is maintained. Can greatly reduce the risk of misfire. Therefore, it is possible to prevent an explosion after a misfire. That is, this rod-shaped body 21 has a function as a flame holding rod.

  Here, the concentric rod-shaped body (flame holding rod) 21 installed in the combustion chamber 11 is that the swirl flow is not easily disturbed by the flame holding rod 21 and the centrifugal force acts on the gas, so that the flame holding rod. Good ignitability and flame-holding property because the gas heated by 21 is difficult to diffuse to the surroundings, and the circumferential velocity decreases as it approaches the flame-holding rod surface, making it difficult for the flame to blow off. Is obtained. Therefore, the present invention is considered to be particularly effective when performing intermittent combustion such as alternating combustion.

  As the form of the outer surface of the flame holding rod 21, even if it is a simple circle, a certain degree of flame holding effect can be expected. However, preferably, the outer surface is provided with irregularities so that the initial flame kernel after ignition is blown away by a swirling flow or the like. It is better not to be. For example, if a plurality of grooves (width 5 mm, depth 5 mm) are arranged on the outer surface of the flame holding rod 21 in the axial direction, a circulation flow is formed in the groove, so the flame holding performance is greatly improved. To do.

  In addition, as for the basic shape of the flame holding rod 21, a certain amount of flame holding effect can be expected even in a cylindrical shape, but preferably from the upstream end (the rear end 11b side of the combustion chamber 11) as shown in FIG. It is better to adopt a tapered truncated cone shape toward the downstream. The main reasons are that the tapered shape can reduce the maximum deflection due to the weight of the flame holding rod 21 in terms of material mechanics, and if a long flame is formed around the flame holding rod 21, it burns downstream. This is because, since the amount of exhaust gas increases, it is desirable to increase the passage cross-sectional area toward the downstream (attenuation of swirling flow can be suppressed).

  Further, regarding the set value of the temperature of the outer surface of the flame holding rod 21, the indicated value of the thermocouple 23 does not necessarily indicate the average temperature of the outer surface of the flame holding rod 21, and the gas accompanying the ignition operation Considering that the flame holding rod 21 is cooled by the flow, etc., it is desirable to set it higher than the ignition temperature of the fuel by about 100 ° C. or more.

  By the way, when a long flame is formed around the flame holding rod 21 after the ignition operation, the outer surface temperature of the flame holding rod 21 is maintained above the ignition temperature of the fuel due to radiation from the flame and heat transfer by the combustion exhaust gas. Therefore, it is only necessary to apply external energy to the flame holding rod 21 at the initial stage of combustion. Therefore, this method has a larger energy saving effect than the conventional pilot burner method.

  Note that the axial length of the flame holding rod 21 is preferably 2 to 10 times the inner diameter of the combustion chamber 11. If the inner diameter of the combustion chamber 11 is less than twice the inner diameter of the combustion chamber 11, the flame holding property against gas supply fluctuations is extremely deteriorated, making it difficult to prevent abnormal combustion. This is because the amount of deflection due to its own weight becomes excessive, the flame axis target property cannot be maintained, and the outer wall of the flame holding rod 21 and the inner wall of the combustion chamber 11 may be burned out.

  Further, the outer diameter (average outer diameter) of the flame holding rod 21 is preferably 0.4 to 0.6 times the inner diameter of the combustion chamber 11. This is because if the outer diameter of the flame holding rod 21 is too small, the heat transfer area becomes smaller and the flame holding performance is worsened. Conversely, if the outer diameter of the flame holding rod 21 is too large, the space of the combustion chamber 11 becomes smaller. This is because there is a risk that the wall becomes narrower and the flame is too close to burn.

  Similarly, if the flame holding rod 21 is too eccentric with respect to the axis of the combustion chamber 11, the flame may approach the inner wall of the combustion chamber 11 and burnout trouble may occur. In addition, the swirl flow is disturbed by the eccentricity of the flame holding rod 21 and the swirl speed is reduced, so that a uniform flame cannot be formed.

  Thus, the long flame burner 1 is provided with the flame holding rod 21 in the combustion chamber 11 so that the flame holding performance is greatly improved. Thus, misfire is avoided and abnormal combustion is prevented. , Safety and reliability are improved. In addition, the operating rate is improved and the repair cost is reduced, so the operating cost is reduced.

  In the long flame burner 1, the combustion exhaust gas of the long flame burner 1 is contained in the fuel-containing gas and / or the oxygen-containing gas. That is, as shown in FIG. 1, the combustion exhaust gas of the long flame burner 1 is mixed with the fuel gas via the flow meter 36, the flow rate adjustment valve 37, and the check valve 38. Similarly, the flow meter 46, the flow rate adjustment valve 47, mixed with air via a check valve 48.

  As a result, the fuel / oxygen concentration is reduced, the slow combustion is promoted, the local high temperature is avoided, and the emission of NOx, which is an environmental load substance, is reduced. In addition, a high exhaust gas recirculation rate is achieved, and as a result, the excess air ratio can be kept small, which significantly reduces exhaust gas sensible heat and improves thermal efficiency, thus saving fuel consumption. It becomes energy saving.

  In FIG. 1, the electric heater 22 is used as the heating means for the flame holding rod 21, but a burner may be used as the heating means for the flame holding rod 21 as shown in FIG. 3.

  That is, FIG. 3A shows a case where a long flame burner is used as a heating means for the flame holding rod 21, and the long flame burner is placed in the hollow portion of the flame holding rod 21 (here, a hollow cylindrical rod-like body). 51 is arranged. 3B shows a case where a commercially available ordinary burner is used as a heating means for the flame holding rod 21. An inner cylinder 53 is installed in the hollow portion of the flame holding rod 21, and the rear end of the inner cylinder 53 is shown. A commercially available normal burner 52 is attached to (on the upstream end side of the flame holding rod 21).

  When the electric heater 22 is used as the heating means for the flame holding rod 21, precise real-time control can be performed, so that reliability is improved. In addition, the incidental equipment becomes compact and the equipment cost is low.

  On the other hand, when the long flame burner 51 is used as the heating means of the flame holding rod 21, before the combustion is started, heat is supplied from the downstream flame, so that an excess enthalpy flame is formed, Since auxiliary fuel and electricity can be saved, the operating cost is low.

  Further, when a commercially available normal burner 52 is used as a heating means for the flame holding rod 21, the operating cost is reduced.

  When the long flame burner 51 or the normal burner 52 is used as the heating means for the flame holding rod 21, the ejector is driven to recirculate the exhaust gas from the combustion exhaust gas of the long flame burner 1 (NOx reduction measures). It can be used as a gas.

  That is, FIG. 4 is provided with an ejector 57 made of low temperature steam or cold air at a position 1/4 of the tube length from the upstream end, and an ejector 56 made of hot gas at a position 1/4 of the tube length from the downstream end. When the combustion exhaust gas discharged from the outlet of the combustion facility (for example, the boiler of the waste incinerator) in which the long flame burner 1 is installed is guided to the / 4 wavelength tube (Rijke Tube) 55, the flame holding rod 21 is heated. The exhaust gas from the long flame burner 51 or the normal burner 52 is used as the drive gas for the ejector 56.

  As a result, a high-temperature blower for exhaust gas recirculation can be omitted, power consumption can be saved, and equipment costs can be reduced. Further, troubles due to burning of high-temperature blowers and dust adhesion are avoided, safety and reliability are improved, and operating costs are reduced.

  By the way, when the exhaust gas from the waste incinerator is recirculated by a high-temperature induction blower, there are problems such as high equipment costs and troubles caused by dust adhering to the blower impeller (abnormal vibration, impeller damage). .

  Further, in the long flame burner 1, the oxygen-containing gas can be preheated by the combustion exhaust gas of the long flame burner 1.

  That is, as shown in FIG. 5, a pair of heat accumulators 61 a and 61 b and a switching valve 62 are installed to preheat the oxygen-containing gas with the combustion exhaust gas of the long flame burner 1 in an alternating manner. Here, Fig.5 (a) shows the state which preheats oxygen-containing gas (air) with the thermal storage body 61a, and heats the thermal storage body 61b with the combustion exhaust gas of the long flame burner 1, FIG.5 (b) shows. The heat storage body 61a is heated by the combustion exhaust gas of the long flame burner 1, and the oxygen-containing gas (air) is preheated by the heat storage body 61b.

  Thus, by preheating the oxygen-containing gas with the combustion exhaust gas of the long flame burner 1, the fuel cost used for the long flame burner 1 can be saved, and the operating cost is reduced. Further, the reactivity of the fuel / oxygen-containing gas is improved, misfire is prevented, and abnormal combustion is prevented, so that the repair cost is reduced and the operation cost is reduced. Furthermore, since misfires are prevented, safety and reliability are improved, and the operating rate is improved and the operating cost is reduced.

  Next, a long flame burner according to the second embodiment of the present invention is shown in FIG. 2A is a longitudinal sectional view, and FIG. 2B is a view taken along the line BB in FIG. 2A.

  As shown in FIG. 2, the long flame burner 2 according to this embodiment is a swirl type long flame burner, and has a combustion chamber 11 with an open end 11 a, and a fuel-containing gas (fuel gas) is supplied to the combustion chamber 11. Combusting a nozzle 12 for fuel-containing gas to be blown in, an oxygen-containing gas supply port 14 for supplying oxygen-containing gas (air) to the combustion chamber 11, and a swirl vane 15 for adding swirl to the supplied oxygen-containing gas The chamber 11 is provided on the rear end 11b side. As a result, a swirling long flame 14 is formed in the combustion chamber 11.

  In the long flame burner 2 as well, as in the long flame burner 1 described above, the flow rate fluctuation mitigation for mitigating the rapid flow rate fluctuation of the fuel containing gas to the pipe for supplying the fuel containing gas to the fuel containing gas nozzle 12. Means 31 is installed, and flow rate fluctuation mitigation means 41 for mitigating rapid flow rate fluctuations of the oxygen-containing gas is installed in a pipe that supplies the oxygen-containing gas to the oxygen-containing gas supply port 14.

  Further, in the long flame burner 2, similarly to the long flame burner 1 described above, a flame holding rod 21 having a circular cross section inserted concentrically into the combustion chamber 11 from the rear end 11 b of the combustion chamber 11, and its holding rod. Flame holding rod heating means (in this case, an electric heater) 24 is provided for maintaining the temperature of the outer surface of the flame rod 21 at or above the ignition temperature of the fuel. A thermocouple 23 is attached to the flame holding rod 21, and the heater controller 24 adjusts the amount of heat input by the electric heater 22 based on the temperature measurement result by the thermocouple 23.

  In addition, about another structure, including the point shown in FIGS. 3-5, it is the same as that of the case of the above-mentioned long flame burner 1. FIG.

  Therefore, also in the long flame burner 2 which concerns on this embodiment, the effect similar to the above-mentioned long flame burner 1 can be acquired, and it is a long flame burner provided with high safety | security and reliability.

  FIG. 6 and FIG. 7 show a radiant tube heating device equipped with the long flame burner 1 or the long flame burner 2 described above. FIG. 6 shows a one-end type radiant tube heating device 71 in which the long flame burner 1 or the long flame burner 2 is installed at one end of a U-shaped radiant tube 75, and FIG. 7 shows both ends of the U-shaped radiant tube 75. These are both-end type radiant tube heating devices 72 provided with a long flame burner 1 (1a, 1b) or a long flame burner 2 (2a, 2b) respectively.

  In the radiant tube heating devices 71 and 72 equipped with such long flame burners 1 and 2, a flame is formed in the space along the radiant tube 75, so that freezing of combustion on the inner wall of the radiant tube is avoided, Emissions of unburned gas and particulate matter that are environmentally hazardous substances are reduced. Moreover, since a stable long flame is formed and a local high temperature is avoided, burning of the inner wall is prevented, repair costs are reduced, and operating costs are reduced. Further, by avoiding local high temperatures, emission of NOx, which is an environmentally hazardous substance, is also reduced. Furthermore, since a stable long flame is formed, the temperature distribution on the outer surface of the radiant tube 75 is averaged, so that the heating efficiency of the heating object (product) is improved, fuel consumption can be saved, and energy can be saved. At the same time, the heating temperature distribution of the product becomes uniform and the quality of the product is improved. In addition, the adjustment range of the heating temperature is expanded and the controllability is improved, so that the facility capacity is improved and the product quality is improved.

  As shown in FIG. 7, in the double-end type radiant tube heating device 72, the heat accumulators 76a provided corresponding to the long flame burners 1a and 1b (or the long flame burners 2a and 2b), 76b is used to perform alternating combustion while preheating oxygen-containing gas (air) with the exhaust gas of the long flame burners 1a, 1b (or the long flame burners 2a, 2b).

  As a result, the actual flow rate of the oxygen-containing gas is increased, and a longer flame is formed. Therefore, the surface temperature of the radiant tube 75 is averaged, and the heating efficiency is improved. It will be cheaper. In addition, since the surface temperature of the flame holding rod 21 provided in the long flame burners 1a and 1b (or the long flame burners 2a and 2b) is made uniform, misfire can be prevented more reliably, Combustion is prevented, repair costs are reduced, and operating costs are reduced.

  And as shown in FIG. 8, the radiant tube 75 may make the internal diameter of the curved pipe part 75b thinner than the straight pipe part 75a, and you may make it connect with the taper pipe 75c between them.

  As a result, the turning speed is increased in the curved pipe portion 75b, the long flame is stably maintained, reaction freezing and incomplete combustion in the vicinity of the inner wall are avoided, and the discharge of particulate matter is reduced. . Moreover, by maintaining a long flame stably, local high temperature is avoided, a heating efficiency improves, and an operating cost becomes cheap. Furthermore, the discharge of NOx, which is an environmentally hazardous substance, is reduced by avoiding local high temperatures. In addition, since the bent pipe portion 75b of the radiant tube 75 is reduced in weight, the equipment cost is reduced.

  When the inner diameter of the curved pipe portion 75b is made thinner than that of the straight pipe portion 75a, the effect of increasing the turning speed to some extent can be expected by connecting both with a stepped pipe, as shown in FIG. As described above, it is preferable that the connection is smoothly made through the tapered tube 75c (the inner diameter has an opening angle of about 30 ° or less) because the hydrodynamic loss accompanying the generation of vortices and the like can be reduced.

  The radiant tube heating devices 71 and 72 detect the differential pressure at both ends of the radiant tube 75 and / or abnormal combustion exhaust gas temperature, and automatically perform operations from purging with an inert gas to re-operation. An automatic operation control device (not shown) is provided.

  When a flame is formed in the radiant tube 75, the average temperature of the gas in contact with the inner wall of the tube increases, and the viscosity of the gas increases, so that the differential pressure across the radiant tube 75 increases. Therefore, by constantly monitoring the differential pressure at the both ends of the radiant tube 75 and / or the combustion exhaust gas temperature, misfiring can be detected quickly and purged with nitrogen gas or the like to prevent abnormal combustion (deflagration, detonation). Can be prevented.

  That is, the automatic operation control apparatus performs control according to the following procedure.

  (S1) An abnormality in differential pressure at both ends of the radiant tube 75 and / or combustion exhaust gas temperature is detected.

  (S2) The on-off valves 35 and 45 of the long flame burner 1 (or the long flame burner 2) are closed, and the supply of the fuel-containing gas and the oxygen-containing gas is stopped.

  (S3) The heat load on the flame holding rod 21 is increased.

  (S4) Purge the radiant tube 75 with nitrogen gas. At that time, the amount of nitrogen gas is set to at least 5 times the internal volume of the radiant tube 75.

  (S5) With the open / close valves 35 and 45 of the long flame burner 1 (or long flame burner 2) opened and the flow rate adjusting valves 33 and 43 being opened, the supply of fuel-containing gas and oxygen-containing gas is resumed. And perform an ignition operation.

  (S6) After gradually increasing the opening of the flow rate adjusting valves 33 and 43 to increase the combustion load, the rated operating conditions are set.

  By performing the control as described above, an appropriate measure can be taken immediately after a misfire, abnormal combustion is prevented, repair costs are reduced, and operating costs are reduced. Further, by preventing abnormal combustion, it is possible to minimize the rate of product failure without proper heating.

  As described above, in the long flame burners 1 and 2 and the radiant tube heating devices 71 and 72 according to the embodiment of the present invention, the flow rate fluctuation mitigation for mitigating rapid flow fluctuations of the fuel-containing gas or oxygen-containing gas. Means 31 and 41 are installed, and a flame holding rod 21 having a surface temperature equal to or higher than the ignition temperature of the fuel to be applied is installed in the combustion chamber 11 of the long flame burners 1 and 2. Even if it fluctuates, it is hard to be affected, and the stability of the flame is greatly improved. Therefore, it is possible to obtain excellent effects such as improvement of safety and reliability, inexpensive operation costs and equipment costs, reduction of environmentally hazardous substances (NOx, particulate matter), energy saving, and improvement of product quality.

1, 1a, 1b Nozzle mix type long flame burner 2, 2a, 2b Swivel type long flame burner 11 Combustion chamber 11a Front end of combustion chamber 11b Rear end of combustion chamber 12 Fuel-containing gas nozzle 13 Oxygen-containing gas nozzle 14 Swirl flame 15 Oxygen-containing gas supply port 16 Swirling blade 21 Rod-shaped body (flame holding rod)
DESCRIPTION OF SYMBOLS 22 Electric heater 23 Thermocouple 24 Heater controller 31 Flow rate fluctuation relaxation means 32 Flow rate measurement means 33 Flow rate adjustment valve 34 Check valve 35 On-off valve 36 Flow meter 37 Flow rate adjustment valve 38 Check valve 41 Flow rate fluctuation relaxation means 42 Flow rate measurement means 43 Flow rate adjusting valve 44 Check valve 45 Open / close valve 46 Flow meter 47 Flow rate adjusting valve 48 Check valve 51 Long flame burner 52 Normal burner 53 Inner cylinder 55 1/4 wavelength tube 56, 57 Ejector 61a, 61b Regenerator 62 Switching valve 71 One-end type radiant tube type heating device 72 Double-end type radiant tube type heating device 75 Radiant tube 75a Straight pipe part 75b Curved pipe part 75c Taper pipes 76a, 76b

Claims (10)

Equipped with a nozzle mix burner equipped with a nozzle that blows fuel-containing gas into the combustion chamber and a nozzle that blows oxygen-containing gas into the combustion chamber, or a swirl vane that adds swirl to the oxygen-containing gas supplied to the combustion chamber In the non-premixed long flame burner consisting of any one of the swirling burners,
Flow rate fluctuation mitigating means for mitigating rapid flow rate fluctuations of the supplied fuel-containing gas or oxygen-containing gas, and a rod-shaped body having a circular cross section tapered downstream from the rear end of the combustion chamber into the combustion chamber And a rod-shaped body heating means for maintaining the temperature of the outer surface of the rod-shaped body at or above the ignition temperature of the fuel ,
The long flame burner , wherein the rod-shaped body has a plurality of axial grooves formed on an outer surface thereof . 2. The long flame burner according to claim 1, wherein an axial length of a portion of the rod-like body inserted into the combustion chamber is within a range of 2 to 10 times an inner diameter of the combustion chamber. . 3. The long flame burner according to claim 1, wherein a heat source of the rod-shaped body heating means is a burner or an electric heater. If the heat source of the rod-like member heating means is turned from the burner, to claim 3, combustion exhaust gas of the burner, characterized in that it is utilized as a driving gas ejector for recirculating the flue gas of the long flame burner The long flame burner described. The long flame burner according to any one of claims 1 to 4 , wherein the oxygen-containing gas is preheated by the combustion exhaust gas of the long flame burner. The fuel-containing gas or to at least one of oxygen-containing gas, the long flame according to any one of claims 1 to 5, characterized in that the combustion exhaust gas of the long flame burner is adapted to be contained Burner. A radiant tube heating device, wherein the long flame burner according to any one of claims 1 to 6 is disposed at one or both ends of a radiant tube. The radiant tube heating device according to claim 7 , wherein when a long flame burner is disposed at both ends of the radiant tube, the long flame burner is configured to alternately burn. The radiant tube heating device according to claim 7 or 8 , wherein an inner diameter of the bent tube portion of the radiant tube is smaller than that of the straight tube portion. Radiant tube differential pressure across also of detecting at least one of one anomaly the combustion exhaust gas temperature, the automatic driving control apparatus for automatically performing an operation to re-run from the purge by inert gas is provided radiant tube heating device according to any one of claims 7-9, characterized in that it is.

Images