JPH06294517A - Premixing combustor - Google Patents

Abstract

PURPOSE:To lower exhaustion of carbon monoxide and unburned hydrogen carbonate and generation of nitrogen oxide by a method wherein plasma gas of high temperature is introduced efficiently into premix gas to generate directly or indirectly H or OH chemical activator, so that combustive reaction speed of the premix gas may be increased, fire flame may be maintained, and thereby combustion may be promoted. CONSTITUTION:A combustor inner cylinder 1 is provided with a premix gas nozzle 3 to generate thin premix gas by mixing fuel and combustion air, and a plasma torch 21 whose operation gas is nitrogen, hydrogen, air or hydrogen carbonate which generate plasma gas to be introduced into the premix gas which has been generated by the premix gas nozzle 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premixing combustor applied to various combustion devices such as gas turbines, boilers and jet engines, and more specifically to premixing suitable for high temperature and low pollution. Regarding combustor.

[0002]

9 to 11 show a conventional premixing combustor. That is, as shown in FIGS. 9 and 10, in the conventional premixed combustor, a small diffusion combustor 2 is provided in the central portion on the upstream side of the combustor inner cylinder 1, and this diffusion combustor is provided. A plurality of premixing nozzles 3 are provided so as to surround the circumference of 2.

As shown in the enlarged view of FIG. 11, the diffusion combustor 2 is provided with a swirl vane 5 inside a cylinder 4 and a fuel injection nozzle 6 penetrating the center thereof. A fuel injection hole 7 is formed at the tip of the fuel injection nozzle 6. Similarly, as shown in FIG. 9, the premixing nozzle 3 also has a structure in which a swirl vane 9 is provided inside a cylinder 8 and a fuel injection hole 10 is provided in the center thereof.

The fuel injection nozzle 6 of the diffusion combustor 2
Is supplied with fuel from a fuel supply source (not shown) through a fuel supply pipe 11, and the fuel injection holes 10 of the respective premixing nozzles 3 are supplied.
The fuel is distributed to and supplied through the fuel supply pipe 12. On the other hand, the combustion air is taken in from the upstream side of the combustor and introduced into the swirl vanes 5 of the diffusion combustor 2 and the swirl vanes 9 of the respective premixing nozzles 3.

The combustion air introduced to the premixing nozzle 3 side is given a swirl force by passing through the swirl vanes 9 and is blown out in front of the fuel injection holes 10. Further, the fuel is ejected from the tip of the fuel ejection hole 10. Therefore, the combustion air to which the swirling force is applied and the fuel ejected from the fuel ejection holes 10 are mixed to form a lean premixed gas, which is introduced into the combustor inner cylinder 1.

Then, a high temperature diffusion flame is formed by the air passing through the swirl vanes 5 of the diffusion combustor 2 and the fuel from the fuel injection nozzle 6, whereby the premixture is burned and the diffusion combustor 2 burns it. A recirculation region 13 is formed in the inner cylinder 1 to hold a flame.

[0007]

The combustion reaction usually begins with the production of H, OH chemically active species that triggers the reaction, but the production of the chemically active species requires a large amount of energy, so that conventional diffusion is required. The high temperature diffusion flame of combustor 2 was not sufficient. Further, due to the high temperature diffusion flame of the diffusion combustor 2, there is a problem that harmful exhaust gas containing a large amount of nitrogen oxides is generated, and it is difficult to suppress the generation of this harmful exhaust gas.

The present invention has been made in order to solve the problems of the prior art as described above, and efficiently injects a high temperature plasma gas into a premixed gas to directly or indirectly generate H,
By generating OH chemically active species, the combustion reaction rate of the premixed gas is increased, flames are held and combustion is promoted, and the emission of carbon monoxide and unburned hydrocarbons and the formation of nitrogen oxides are suppressed. An object of the present invention is to provide a premixed combustor that can be used.

[0009]

In order to solve the above problems, a premixing combustor according to the present invention includes a premixing nozzle for mixing a fuel and combustion air to produce a lean premixed gas. A plasma torch using nitrogen, hydrogen, air or hydrocarbon as a working gas to generate a plasma gas to be injected into the premixed gas generated by the premixing nozzle; and the plasma torch and the premixing nozzle. And a combustor.

[0010]

[Operation] According to the above means, a high temperature plasma gas is generated by a plasma torch using nitrogen, hydrogen, air or hydrocarbons as a working gas, and the high temperature plasma gas is injected directly or directly into the premixed gas. H, OH chemically active species can be generated indirectly. Therefore, the combustion reaction rate of the premixed gas can be increased, the flame can be maintained, the combustion can be promoted, and the generation of nitrogen oxides can be suppressed.

[0011]

Embodiments of the premixed combustor according to the present invention will be described in detail below with reference to FIGS. 1 to 8. In these figures, the same parts as those in FIGS. 9 to 11 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a side sectional view of a first embodiment of a premixing combustor according to the present invention, and FIG. 2 is an explanatory view showing a sectional view in the direction of arrow A in FIG. That is, according to this embodiment,
In the premix combustor, a plasma torch 21 is provided in the central portion on the upstream side of the combustor inner cylinder 1, instead of the diffusion combustor 2. A plurality of premixing nozzles 3 are provided so as to surround the plasma torch 21.

An example of the structure of the plasma torch 21 is shown in FIGS. 3 and 4, FIG. 3 is a side sectional view of the plasma torch 21, and FIG. 4 is a sectional view taken along line BB of FIG.
The plasma torch 21 has a tubular body 22 made of an electrically insulating material, and a support base 23 extending from an end portion that closes one end side of the tubular body 22 to a central portion of the tubular body 22. Stand 2
An anode nozzle 2 which is supported by 3 and is provided with a cathode 24, and which also serves as a nozzle extending from the cylindrical body 22 around the cathode 24.
5 is provided.

Then, from the base side of the support base 23, the cylindrical body 22
In order to introduce the working gas into the inside, a pair of gas introduction pipes 26
Is installed. Furthermore, the cathode 24 and the anode nozzle 2
A DC voltage is applied between the terminals 5 and 5 by the power supply 27. As the working gas, nitrogen, hydrogen, air, hydrocarbon or the like is used.

Next, the operation of the premixed combustor of the present invention thus constructed will be described. A discharge column is formed by applying a DC voltage between the cathode 24 and the anode nozzle 25 of the plasma torch 21. On the other hand, the working gas such as nitrogen, hydrogen, air, or hydrocarbon introduced into the cylindrical body 22 through the pair of gas introduction pipes 26 tangentially flows from the periphery of the support base 23, and has a strong swirling force, and the cathode 24 and the anode. It passes through the nozzle 25. Then, when the working gas traverses the discharge column, it receives a large amount of electric energy, and the working gas becomes a plasma state and the plasma torch 2
It is discharged from the tip of 1.

The plasma gas discharged from the tip of the plasma torch 21 contracts so that the thermal energy loss of the plasma gas itself is minimized, and the energy density is increased, so that the plasma gas at a higher temperature is autonomously supplied. Will be formed.

The high-temperature plasma gas emitted from the plasma torch 21 is injected into the lean premixed gas sent from the premixing nozzle 3 to the combustor inner cylinder 1 to ignite the premixed gas and hold the flame, It promotes combustion and acts to prevent misfire. That is, the combustion reaction starts from the generation of H, OH chemically active species that triggers the reaction, but in the case of generating plasma gas by the plasma torch 21 of the present invention, H or OH chemistry is directly or indirectly generated. Since the active species can be generated, the combustion reaction rate of the premixed gas can be increased, the flame can be retained, the combustion can be promoted, and the generation of nitrogen oxides can be suppressed.

Next, FIGS. 5 and 6 show a second embodiment of the present invention. In the present embodiment, the present invention is applied to a premixed combustor having a conventional diffusion combustor 2. That is, since the diffusion combustor 2 is provided in the central portion surrounded by the premixing nozzle 3, a plurality of plasma torches 21 are radially arranged symmetrically around the outer circumference of the combustor inner cylinder 1 in this embodiment. . Therefore, without using the diffusion combustor 2,
The premixed gas is ignited by the plasma gas generated by the plasma torch 21 to promote combustion.

Further, FIGS. 7 and 8 show a third embodiment of the present invention. This embodiment is the same as the second embodiment described above.
In the embodiment described above, when a plurality of plasma torches 21 are radially arranged on the outer circumference of the combustor inner cylinder 1, the symmetry of the combustor is lost when a sufficient space for mounting the plasma torch 21 cannot be obtained. One or more plasma torches 21 are arranged asymmetrically on the outer circumference of the combustor inner cylinder 1 so that the high temperature plasma gas is injected into the premixed gas.

In the present invention, it is important that the high temperature plasma gas is efficiently injected into the lean premixed gas from the premixing nozzle 3, and the position of the plasma torch 21 arranged in the combustor is It's not that important. Also,
Gas introduction pipe 2 for introducing working gas to the plasma torch 21
The number 6 may be one instead of a pair.

[0021]

As described in detail above, the premixed combustor according to the present invention generates plasma gas by the plasma torch using nitrogen, hydrogen, air or hydrocarbon as the working gas,
Since this high-temperature plasma gas is efficiently injected into the premixed gas, it is possible to directly or indirectly generate the H, OH chemically active species. Therefore, the combustion reaction rate of the premixed gas can be increased, the flame can be maintained, the combustion can be promoted, the emission of carbon monoxide and unburned hydrocarbons can be suppressed, and the generation of nitrogen oxides can be suppressed. A very remarkable effect can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view of a first embodiment of a premixing combustor according to the present invention.

FIG. 2 is an explanatory diagram showing a cross section in the direction of arrow A in FIG.

FIG. 3 is a side sectional view showing the plasma torch in FIG. 1 in detail.

4 is a cross-sectional view taken along the line BB of FIG.

FIG. 5 is a side sectional view of a second embodiment of the premixing combustor according to the present invention.

6 is an explanatory view showing a cross section in the direction of arrow C in FIG.

FIG. 7 is a side sectional view of a third embodiment of the premixing combustor according to the present invention.

FIG. 8 is an explanatory view showing a cross section in the direction of arrow D in FIG.

FIG. 9 is a side sectional view showing a conventional premix combustor.

10 is an explanatory diagram showing a cross section taken along arrow E in FIG.

FIG. 11 is a side sectional view of a diffusion combustor included in a conventional premix combustor.

[Explanation of symbols]

 1 Combustor inner cylinder 3 Premixing nozzle 21 Plasma torch

Front page continuation (72) Inventor Shigemi Bandai 1-1-1 Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Plant

Claims (1)

[Claims] 1. A premixing nozzle that mixes fuel and combustion air to generate a lean premixed gas, and a plasma gas to be injected into the premixed gas generated by this premixing nozzle. A premixed combustor comprising a plasma torch using nitrogen, hydrogen, air or hydrocarbon as a working gas, and a combustor provided with the plasma torch and the premixing nozzle.