JPS5840409A - Combustor - Google Patents

Abstract

PURPOSE:To reduce sharply the generation of carbon monoxide or unbrunt hydrocarbon, etc. by a method wherein an ultra-rarefied premixed gas from a mixer of a combustor such as a gas turbine, etc. is supplied to the combustion gas from the combustion unit and mixed therewith, then passed through the catalyst layer. CONSTITUTION:Primary fuel from the primary combustion nozzle 301 and primary air from the primary air nozzle 302 are mixed at the primary combustion unit 308 and burnt by the dispersed flame, etc. Several mixers 305 are installed around the primary combustion unit 308, while the secondary fuel from the secondary fuel nozzle 303 and the secondary air from the secondary air inlet port 304 are mixed at the mixing unit 305 to form an ultra-rarefied premixed gas. At the mixing unit 309, the ultra-rarefied premixed gas from the mixing unit 305 is supplied to the primary combustion gas and mixed therewith, flowed into the catalyst layer 307 and burnt therein. It is possible to reduce the production of CO or UHC, perform a combustion of the ultra-rarefied premixed gas and reduce the generation of NOx.

Description

[Detailed Description of the Invention] In gas turbine combustors and jet engine combustors, combustion efficiency is improved, and nitrogen oxides (NOx), carbon monoxide (CO), and unburned hydrocarbons generated as fuel is burned. (UHC) and the like is a challenge.

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

This combustor (100) has a pilot fuel nozzle (10
1) and the primary air nozzle (102)
The main fuel supplied from the main fuel nozzle (l03) provided downstream is evaporated and mixed in the fuel processing area (l05), and then the catalyst # (10 It flows into the water and burns it.

Therefore, in such a combustion method, the main fuel nozzle (103
) The fuel burns as a diffusion flame in the area where the fuel is supplied from the catalyst layer (104), which has the drawback that the conditions for combustion in the catalyst layer (104) in a completely mixed state of fuel and air are very narrow. Therefore, it was not possible to reduce CO and UHC 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, (204) is the primary air nozzle, and (204) is the primary air nozzle. is the secondary fuel nozzle, (205) is the secondary air flow, (
206) is the secondary combustion zone, (207) is the catalyst layer, 208 is the casing, and (209) is the igniter.

In this combustor (200), 1
The primary fuel from the primary fuel 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). 206), the secondary fuel from the secondary fuel nozzle (204) and secondary air (205) are mixed and then flowed into the catalyst layer (207) where they are 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 becomes 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
This was done for the purpose of making it possible to burn an ultra-lean premixture to achieve low NOx combustion.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG.

FIG. 3 is a schematic cross-sectional view showing the main parts of an embodiment of the combustor according to the present invention, (301) is the primary fuel nozzle, (301) is the primary fuel nozzle;
302) is the primary air nozzle, (303) is the secondary fuel nozzle, (304) is the secondary air introduction part, (3os) is the mixer, (aO is the swirler, (307) is the catalyst layer,
08) is the primary combustion section, and (309) is the mixing section.

In the combustor of the present invention, first, the primary fuel nozzle (primary fuel and primary air from 30) and the primary air from the nozzle (302) are mixed in the primary combustion part (30B), It is burned by diffusion flame etc. A large number of mixers (305) are provided around the primary combustion section (308).
05), the secondary fuel from the secondary fuel nozzle (aOa) is mixed with the secondary air from the secondary air introduction part (304) to create an ultra-lean premixture. The combustion gas burned in the primary combustion section (308) flows toward the mixing section (309) as shown by an arrow (310). Then, the ultra-lean premixture from the mixer (305) is supplied and mixed into the primary combustion gas in the mixing part (309), and this mixed gas is mixed with the primary combustion gas in the mixing part (309).
309) It flows into the rear catalyst layer (307) and is burned there. This catalyst layer (307) is composed of Co-? U
Needless to say, it oxidizes HC and converts it into carbon dioxide gas (CO2) and water (H2O), thereby significantly reducing the amount of Co and TJHC in the gas.

Note that the gas that has passed through the catalyst layer (307) is sent to a gas turbine (not shown) or the like.

According to the combustor of the present invention, the following effects can be obtained.

(1) Since the primary fuel burns with primary air and a diffusion flame (or a premixed flame), NOx per combustion amount
Although there are many oxidants, the combustion amount is small at 10 to 30%, so the amount of NOx at the combustor outlet is small.

(2) The secondary fuel becomes an ultra-lean premix in the mixer (305) and then burns in the catalyst layer (307), but since it is an ultra-lean premix, the amount of NOx produced here is very small. few. In addition, since there is a large amount of secondary fuel, the amount of NOx at the combustor outlet is extremely small.

(3) The combustion range of an ultra-lean premixture is extremely narrow because it is regulated by both NOx generation, catalyst layer heat resistance, or combustible mixture concentration. However, as in the present invention, the primary fuel combustion gas and the ultra-lean premixture are mixed and the mixture temperature increases and then flows into the catalyst layer, so the combustion range is significantly expanded compared to the conventional method. .

In other words, it is UHC even if an ultra-lean mixture is combusted.

CO emissions are low.

(4) It is easy to preheat the catalyst layer by the movement of the primary fuel during ignition, and the combustion gas flows into the catalyst layer after mixing with secondary air, so the catalyst layer does not overheat or burn out. .

As described above, according to the present invention, the performance of gas turbine combustors, jet engine combustors, etc. that significantly reduces the generation of CO and UHC, and enables combustion with ultra-lean premixture to reduce the generation of NOx. A combustor that greatly contributes to improvements is provided.

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, the mixer (305) may be a plurality of pipes.

[Brief explanation of the drawing]

1 and 2 are sectional views showing a conventional combustor, and FIG. 3 is a sectional view schematically showing essential parts of an embodiment of a combustor according to the present invention.

Claims (1)

[Claims] a combustion section that mixes the primary fuel with the primary air and burns it;
a mixer that mixes secondary fuel and secondary air to obtain an ultra-lean premix; a mixing section that supplies and mixes the ultra-lean premix from the mixer into the combustion gas from the combustion section; A combustor comprising a catalyst layer provided behind the mixing section.