JP2005188858A - Combustion control method for tubular flame burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preheating and then stably distributing and supplying fuel, oxygen content gas or a premixture thereof to supply nozzles of primary gas for combustion and secondary gas supplied to an outer peripheral part of combustion flame, by a simple device. <P>SOLUTION: When fuel, oxygen content gas or the premixture thereof is heat-exchanged with exhaust gas by a heat exchanger, the fuel, oxygen content gas or the premixture thereof is heat-exchanged with high temperature gas by heat exchangers arranged for every supply line to a plurality of nozzles for supplying the fuel, oxygen content gas, the premixture thereof or inert gas to a tubular flame burner, or heat-exchanged with high temperature gas in one heat exchanger for every supply line of the fuel, oxygen content gas, the premixture thereof or inert gas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a combustion control method for a tubular flame burner, and in particular, a primary gas or fuel supplied to a combustion chamber, an oxygen-containing gas, or a mixture of these in advance, or a secondary gas composed of an inert gas is used in a heat exchanger. The present invention relates to a method for stably distributing and supplying nozzles after preheating.

  Since the tubular flame burner forms a stable flame in a high-speed swirling flow in the combustion chamber, the temperature of the combustion flame is stabilized and a local high temperature region is not formed. In addition, since it is possible to reduce the oxygen ratio and the air ratio to reduce unburned components such as NOx and hydrocarbons and environmental pollutants such as soot, they are used in various types of heating devices.

  As for the radiant tube type heating device, a radiant tube type heating device in which a tubular flame burner is attached to the open end of the radiant tube and the amount of NOx generated is smaller than that in the case of using a conventional burner is not yet applied by the applicant. It is described in the published prior application. The application number is Japanese Patent Application No. 2002-236958.

  However, recently, interest in the global environment has rapidly increased, and there has been a demand for reducing the amount of NOx generated from a heating furnace or the like as compared with the prior art. In a low-growth economy, extending the life of factory equipment is also an issue.

  Therefore, in order to reduce the generation amount of earth pollution sources such as NOx in the tubular flame burner and to reduce the spread of the combustion flame, the primary gas for combustion and the secondary gas supplied to the outer periphery of the combustion flame, It has been studied to preheat and mix oxygen-containing gas or a mixture of these in advance.

  FIG. 6 is a schematic sectional side view of a tubular flame burner for ejecting secondary gas to the outer peripheral portion of the combustion flame. The tubular flame burner 1 ejects secondary gas c from the outer peripheral portion of the tubular combustion chamber 13. The tubular combustion chamber 13 is provided with a nozzle 11 a for ejecting fuel a into the combustion chamber 13 and a nozzle 11 b for ejecting oxygen-containing gas b into the combustion chamber 13. Nozzles 11c and 11d for ejecting c are attached.

  These nozzles are supplied with fuel, oxygen-containing gas or e1 e2, e3 obtained by premixing these with the combustion exhaust gas f in the heat exchanger 4a. Each nozzle is distributed by a switching valve (not shown in the figure) at a branch point g.

  However, since the gas preheated by the exhaust gas from the tubular flame burner is high in temperature, a cooling device or the like is required to stably operate the switching valve, and the equipment becomes complicated.

  Therefore, the present invention is simple after preheating a fuel, an oxygen-containing gas, or a mixture of these in advance in a supply nozzle for a secondary gas supplied to the outer periphery of the primary gas for combustion or combustion flame using a heat exchanger. It is an object of the present invention to provide a method for stably distributing and supplying with a simple apparatus.

The object of the present invention can be achieved by the following means.
In a tubular flame burner that is preheated from a plurality of nozzles together with a primary gas for combustion, a premixed fuel, or a mixture thereof, or a tubular flame burner that supplies an inert gas into the combustion chamber, the fuel, oxygen-containing gas, or A tube in which these are mixed in advance, or when an inert gas is heat-exchanged with a high-temperature gas by a heat exchanger, heat is exchanged with the high-temperature gas for each supply path to the plurality of nozzles. Flame burner combustion control method.

  2 Further, the preheated fuel, oxygen-containing gas, or a mixture thereof, or an inert gas is used as a secondary gas ejected from a side chamber provided along the outer periphery of the combustion chamber, and the secondary gas supply 2. The method for controlling combustion of a tubular flame burner according to 1, wherein heat is exchanged in the heat exchanger for each path.

  3. The method of controlling combustion of a tubular flame burner according to 1 or 2, wherein the primary gas and / or the secondary gas is heat-exchanged for each supply path in one heat exchanger.

  4. The method of controlling combustion of a tubular flame burner according to 1 or 2, wherein heat exchange is performed on the primary gas and / or the secondary gas in a heat exchanger provided for each of the supply paths.

  According to the present invention, a preheated fuel, an oxygen-containing gas, a premixed mixture of these, or an inert gas can be mixed stably with the primary gas for combustion and the secondary gas supplied to the outer peripheral portion of the combustion flame. As a result, a tubular flame burner with a small amount of NOx and other earth pollution sources and a small flame spread is obtained. When used in a radiant tube heating device, there is little thermal degradation such as wear and cracking of the radiant tube, It can achieve a long life and is extremely useful in industry. Moreover, since the amount of generated NOx is small, it is preferable in terms of the global environment.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a side sectional view showing an example of a tubular flame burner to which the combustion method of the present invention is applied. In the figure, 1 is a tubular flame burner, 11a and 11b are primary gases (fuel and oxygen-containing gas and 11c and 11d are nozzles for blowing the secondary gas c supplied to the outer peripheral portion of the combustion flame into the side chamber 12, and 12 is an annular side chamber provided at the outer peripheral portion of the combustion chamber. Is a combustion chamber, a is a fuel, b is an oxygen-containing gas, c is a secondary gas, d is a swirling flow by the fuel a and the oxygen-containing gas b.

  The tubular flame burner 1 opens toward the tangential direction of a tubular combustion chamber 13 whose one end is opened and the inner surface of the combustion chamber 13, and nozzles 11a and 11b for injecting fuel a and oxygen-containing gas b, respectively, and the combustion A side chamber 12 provided in an annular shape along the outer periphery of the chamber 13 is provided, and the side chamber 12 is provided with nozzles 11d and 11c for ejecting the secondary gas c linearly along the ejection direction of the combustion flame.

  In the following description of the present invention, the fuel and the oxygen-containing gas or a gas obtained by premixing them and the gas blown into the combustion chamber 13 is defined as a primary gas. The fuel, the oxygen-containing gas, the gas premixed with these, or the inert gas supplied to the outer periphery of the combustion flame is used as the secondary gas. The inert gas is preferably steam or Ar gas for reducing NOx.

  FIG. 3 is a schematic diagram for explaining a method of burning a tubular flame burner according to an embodiment of the present invention. In the figure, 4b, 4c, and 4d are high-temperature gas f and fuel, oxygen-containing gas, or a mixture of these in advance. Or a heat exchanger for exchanging heat with an inert gas, f is a high-temperature gas, for example, exhaust gas of the tubular flame burner 1 or exhaust gas of a tubular flame burner that alternately burns with the flame burner 1.

  In this embodiment, when preheating and mixing fuel, oxygen-containing gas, or gases e1, e2, e3 obtained by premixing these with primary gas a, b or secondary gas c, heat provided for each nozzle to be blown in Heat is exchanged with the high-temperature gas f by the exchanger, and the preheated gas that has passed through the heat exchanger and has reached a high temperature is blown without being distributed by the switching valve.

  The primary gas a supplied to the nozzle 11a is mixed with fuel, oxygen-containing gas, or gas e1 obtained by premixing these with the heat exchanger 4b and the high-temperature gas f.

  The secondary gas c supplied to the nozzle 11c is mixed with a fuel, an oxygen-containing gas, or a gas or an inert gas e2 obtained by premixing these with the high-temperature gas f in the heat exchanger 4c. The primary gas b supplied to the nozzle 11b is blown with fuel, oxygen-containing gas, or gas e3 obtained by premixing these with the heat exchanger 4d that exchanges heat with the high-temperature gas f.

  FIG. 4 shows another embodiment of the present invention, in which fuel, oxygen-containing gas, or gases e1, e2, and e3 obtained by premixing them are heated at a high temperature for each supply path in one heat exchanger 4c. Preheat by exchanging heat with gas f.

  The high-temperature gas f used for preheating in the heat exchanger is a tubular flame burner that blows fuel, oxygen-containing gas, or gases e1, e2, and e3 premixed with these, or a tubular flame burner that alternately burns with the flame burner. It is preferable to use what is generated.

  FIG. 1 shows a radiant tube type heating device in which a tubular flame burner is attached to both ends of a radiant tube. The tubular flame burner is alternately burned, and the exhaust gas, fuel, oxygen-containing gas, or gas premixed with these exhaust gases After e is preheated by the heat exchanger 4, it is supplied to each tubular flame burner. FIG. 1 shows a case where one heat exchanger 4 is preheated by the method shown in FIG. 5, but it is also possible to provide a heat exchanger for each supply path as shown in FIG.

  FIG. 5 shows a radiant tube type heating device in which a tubular flame burner is attached to one end of a radiant tube, and a heat exchanger can be provided at an end portion where exhaust gas is ejected.

In the above description of the present invention, a tubular flame burner having a combustion chamber with one tubular end opened is used. However, even with a tubular flame burner with both ends of the combustion chamber opened, the operational effects of the present invention can be obtained. It will not be damaged.
Further, the method for burning a tubular flame burner according to the present invention is not limited to application to a radiant tube # type heating device, and can also be applied to a heating device of a direct fire combustion type.

The figure which shows an example of the radiant tube type heating apparatus to which this invention is applied. The figure which shows an example of the tubular flame burner to which this invention is applied. The figure which shows one Embodiment of this invention. The figure which shows other embodiment of this invention. The figure which shows the other example of the radiant tube type heating apparatus to which this invention is applied. Conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tubular flame burner 11a Nozzle which injects fuel 11b Nozzle which injects oxygen-containing gas 11c, 11d Nozzle which injects secondary gas 12 Side chamber 13 Combustion chamber 2 Radiant tube 3 Radiant tube type heating device 4, 4a, 4b, 4c, 4d Heat exchange 5 Switching valve a Fuel b Oxygen-containing gas c Secondary gas d Swirl e, e1, e2, e3 Fuel, oxygen-containing gas, or a premixed mixture thereof f High-temperature gas g Branch point

Claims (4)

A fuel, oxygen-containing gas or a premixed mixture thereof, or a tubular flame burner for supplying an inert gas into a combustion chamber, which is preheated together with a primary gas for combustion from a plurality of nozzles. A tubular flame characterized in that when the inert gas is heat-exchanged with a high-temperature gas by a heat exchanger, heat is exchanged with the high-temperature gas for each supply path to the plurality of nozzles. Burner combustion control method. Further, the preheated fuel, oxygen-containing gas or a premixed gas thereof, or an inert gas is used as a secondary gas ejected from a side chamber provided along the outer periphery of the combustion chamber, and the secondary gas supply path 2. The method of controlling combustion of a tubular flame burner according to claim 1, wherein heat is exchanged in the heat exchanger every time. The method for controlling combustion of a tubular flame burner according to claim 1 or 2, wherein the primary gas and / or the secondary gas is heat-exchanged for each supply path in one heat exchanger. The method for controlling combustion of a tubular flame burner according to claim 1 or 2, wherein the primary gas and / or the secondary gas is subjected to heat exchange in a heat exchanger provided for each of the supply paths.

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