JPS5840408A - Combustor - Google Patents

Abstract

PURPOSE:To prevent the production of carbon monoxide or unburnt hydrocarbon by a method wherein a thermostat made of heat-resistant material for making a uniform temperature distribution of combustion gas in the flow passage is arranged in front of a catalyst unit placed in the combustion gas passage of the combustor such as a gas turbine. CONSTITUTION:To the interior of a main body 301 of a combustor are supplied both fuel and air in a direction of the arrow 302. Within the main body 301 of the combustor is placed a thermostat 304 formed of a filling structure of heat- resistant material such as carbon fiber or mulite, and the catalyst unit 305 is placed in series with the thermostat 304 with a desired space apart therebetween. Thus, it is possible to reduce substantially a volume of produced CO or UHC. Therefore, it is also possible to perform the combustion caused by the ultra lean mixture gas to reduce the production of NOx and further to improve the efficiency of combustion of a gas turbine combustor or a jet engine combustor.

Description

[Detailed description of the invention] The present invention relates to improvements in combustors.

In gas turbine combustors and jet engine combustors, as well as improving combustion efficiency, the amount of nitrogen oxides (NOX), -carbon oxides (CO), unburned hydrocarbons (UHC), etc. generated as a result of fuel combustion has been improved. The challenge is to suppress this.

Figure 1 shows an example of this type of combustor (100), where (101) is a pilot fuel nozzle, (10
2) is the primary air nozzle, (103) is the main fuel nozzle, (
to4) is a catalyst layer, and (105) is a fuel processing area, which is provided within the casing (106).

This combustor (100) has a pilot fuel nozzle (10
Fuel supplied from 1λ and primary air nozzle (102)
The main fuel supplied from the main fuel nozzle (103) provided downstream is evaporated and mixed in the fuel processing area (105), and then the catalyst layer (104) is mixed with air supplied from the main fuel nozzle (103). ) and burn it.

Therefore, in such a combustion method, the main fuel nozzle (103
) The fuel is combusted as a diffusion flame in the area where the fuel is supplied from the catalytic converter (104), and the conditions for combustion in the catalyst layer (104) in a completely mixed state of fuel and air are extremely narrow. Therefore, CO and UHC could not be reduced much.

Figure 2 shows another conventional combustor (200), where (201) is the primary fuel nozzle, (202) is the primary air nozzle, (203) is the primary combustion zone, and (204) is the primary combustion zone. is the secondary fuel nozzle, (205) is the secondary air flow, (2o
(207) is the catalyst layer (208) is the casing, and (209) is the igniter.

In this combustor (200), 1
The primary fuel from the secondary combustion nozzle (201) and the primary air from the primary air nozzle (202) are mixed and combusted, and a secondary combustion area (203) is provided around the primary combustion area (203). 20-6) from the secondary fuel nozzle (204).
After mixing the secondary fuel and secondary air (205), it flows into the catalyst layer (207) where it is combusted.

Therefore, in this combustion method, the temperature of the catalyst layer (207) is
Adjustment is made only by the mixture ratio of secondary fuel and secondary air,
The flammable range is very narrow (so CO and UHC
The disadvantage was that it was not possible to sufficiently reduce the

The present invention eliminates the conventional drawbacks as mentioned above, and
The purpose of this invention is to enable the combustion of an ultra-lean premixture in order to achieve low NOx combustion, and one embodiment of the present invention will be described in detail below with reference to Figures 3 to 5. explain.

FIG. 3 is a diagram showing the main parts of an embodiment of the combustor according to the present invention, and shows the inside of the combustor main body (30).

A temperature equalizer (304) made of a structure filled with a heat-resistant material such as carbon fiber or mullite is provided in the combustor body (301), and a temperature equalizer (304) is provided in series with the temperature equalizer (304) and at a predetermined location. A catalytic converter (305) is provided with a space of .

Then, the fuel and air supplied from the direction of arrow (302) are mixed and burned by a method such as burner combustion, and the combustion gas flows to the right in the figure (in the direction of arrow (303)), such as a gas turbine (not shown), etc. supplied to By the way, when we measure the temperature distribution of the combustion gas in front of the temperature equalizer (304) (part 8), as shown in Figure 4(a), the temperature in the center of the combustor body (301) is high, and the temperature in the surrounding area is high. The temperature distribution is uneven, with the temperature being lower in some areas. However, as shown in FIG. 4(b), the temperature distribution at the intermediate part (b) between the temperature equalizer (304) and the catalytic converter (305) is affected by the heat conduction effect of the temperature equalizer (304). The main body (301
) The center and periphery of the catalytic converter (305) have a similar temperature, and this uniform temperature distribution is maintained even at the rear (part C) of the catalytic converter (305).
As shown in Figure (c), it is uniform.

Next, NO in the combustion gas at each temperature measurement point above
After measuring the amounts of x, Co, and UHC,
Since 04) has no catalytic action, its composition does not change at all before and after the temperature soaker (304), as shown at points a and b in FIG. However, behind the catalyst (305), the catalyst oxidizes CO and UHC in the combustion gas to produce carbon dioxide (
CO2) and water (H2O), the amounts of CO and TJHC are significantly reduced, as shown at point C in Figure 5.

Note that the catalytic converter (305) generally has poor durability at high temperatures, and if the temperature locally becomes high, the catalytic action in that area will not be effectively exerted; however, in the present invention, the catalytic converter (305)
) is provided in front of the catalytic converter (304) to even out the combustion gas temperature distribution, so that the catalytic converter (305) can function extremely effectively.

As described above, according to the present invention, the generation of CO and UHC can be significantly reduced by using a temperature equalizer and a catalyst in combination. Therefore, it is possible to perform combustion using an ultra-lean premixture to reduce the generation of NOx, and this can greatly contribute to improving the combustion efficiency of gas turbine combustors, jet engine combustors, and the like.

It goes without saying that the present invention is not limited to the above-mentioned embodiment, but can be implemented with various modifications without departing from the scope of the invention. For example, although a cylindrical combustor body is shown as the combustor main body (30), it may be of any suitable shape, and a temperature equalizer or catalyst may be provided in accordance with the shape.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views showing a conventional combustor;
The figure shows a main part of an embodiment of a combustor according to the present invention,
Fig. 4 is a diagram showing the temperature distribution of each part in the combustor according to the present invention, and Fig. 5 is a diagram showing the temperature distribution of CO, UHo at each temperature measurement point.
FIG. 3 is a diagram showing the amount of lNox. (301)...Combustor body, (304)...Temperature equalizer, (
305)...Catalyst.

Claims (1)

[Claims] In a combustor that uses a catalyst to reduce oxides, etc. in the combustion gas produced as a result of fuel combustion, a combustor made of heat-resistant material is placed in front of the catalytic converter installed in the combustion gas flow path. A combustor characterized by being equipped with a temperature equalizer to equalize the temperature distribution of combustion gas in a flow path.