JP2518997Y2 - Catalytic combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention mainly relates to a catalytic combustor used in a gas turbine.

[Prior Art] Conventionally, as a combustor of a gas turbine, a catalytic combustor that burns a mixture of fuel and air while passing through a large number of narrow combustion passages formed inside a catalyst carrier has been known. An example of this type of combustor is shown in FIG.

In this figure, 1 is a gas turbine combustor, 2 is a combustor outer cylinder, 3 is an inner cylinder, and an air passage 4 is formed between the inner and outer cylinders 2 and 3. 5 is a fuel nozzle for the primary fuel F, 6
Is an air hole formed in the inner cylinder 3, and 7 is a premixing tube for secondary fuel. The premixing pipe 7 faces the inner cylinder 3, and introduces a thin premixed gas Mp of fuel and air into the inner cylinder 3. Reference numeral 8 denotes a catalyst carrier, which is composed of a ceramic structure in which a large number of thin passages are polymerized, and a catalyst such as platinum is attached to the surface of the thin passages to form a thin combustion passage 8a. The arrow A indicates the flow of air.

Since this catalytic combustor 1 is capable of low temperature combustion, it has an advantage that the generation of thermal NOx due to high temperature combustion can be controlled.

[Problems to be Solved by the Invention] However, in the vicinity of the inlet of the catalyst carrier 8, since the air-fuel mixture is not sufficiently mixed, the concentration distribution is non-uniform. When the air-fuel mixture having a non-uniform concentration is introduced into the catalyst carrier 8 in this manner, the combustion passage 8a extends toward the downstream M for a long time, so that the air-fuel mixture remains in a non-uniform concentration distribution and the air-fuel mixture is left in the combustion passage 8a. Burns inside. Therefore, in the combustion passage where the air-fuel mixture concentration is low, combustion becomes insufficient and the overall combustion efficiency is reduced.

Therefore, as shown in FIG. 5, the catalyst carrier 8 is divided into a plurality of divided bodies 8b along the flow direction of the air-fuel mixture (direction of arrow M), and the annular spacer 9 is arranged between the divided bodies 8b. hand,
It is conceivable to form the gap 10 and mix the gas in the gap 10 to make the concentration distribution uniform. However, in this case, the gas does not pass through the combustion passage 8a closed by the spacer 9 in the outer peripheral portion 8c of the catalyst carrier, so that the combustion reaction does not occur.
The outer peripheral portion 8c has a much lower temperature than the central portion 8d. Therefore, thermal stress is generated due to the temperature difference between the central portion 8d and the outer peripheral portion 8c, and cracks occur near the outer peripheral portion 8c of the catalyst carrier 8.

JP-A-63-213723 discloses a catalytic combustion apparatus in which the cross-sectional area of the combustor is made smaller toward the downstream side, and in accordance with this, the catalyst carrier divisions are also made smaller toward the downstream side. However, this device has a drawback that the shape of the combustor and the catalyst carrier is complicated and the productivity is poor.

The present invention has been made in view of the above circumstances, and prevents the catalyst carrier from being cracked due to the temperature difference between the central portion and the outer peripheral portion while having a configuration capable of realizing uniform gas concentration distribution and improving combustion efficiency. It is an object of the present invention to provide a catalytic combustor that can be manufactured and that is also excellent in productivity in terms of shape.

[Means for solving the problem]

In order to achieve the above object, the catalytic combustor according to the present invention has a plurality of catalyst carriers forming a plurality of narrow combustion passages through which a mixture of fuel and air flows, along a flow direction of the mixture. In a catalytic combustor, which is divided into divided bodies, a ring-shaped spacer that is in contact with the peripheral wall of the combustor between the divided bodies, is sandwiched between the divided bodies, and holds a gap between the divided bodies, The spacer is formed of a structure having a gas passage extending in the flow direction in a portion of the outer periphery of the catalyst carrier corresponding to the combustion passage.

[Action]

According to this invention, by holding a gap between the divided bodies of the catalyst carrier, it is possible to mix the air-fuel mixture in the gap to make the concentration distribution uniform and improve the combustion efficiency.

A ring-shaped spacer sandwiched between the divided bodies so as to form a gap for exhibiting such a function has a gas passage extending in the flow direction of the air-fuel mixture at a portion corresponding to the combustion passage on the outer periphery of the catalyst carrier. Since the combustion passage in the outer peripheral portion of the catalyst carrier is not blocked by the spacer, it is possible to flow the air-fuel mixture into the combustion passage in the outer peripheral portion of the catalyst carrier for catalytic combustion. By making the temperature difference between the outer peripheral portion and the central portion small, it is possible to prevent the catalyst carrier from cracking due to thermal stress.

Further, the combustor can be made into a simple cylindrical shape in which the cross-sectional area does not change in the axial direction, and similarly, each divided body of the catalyst carrier can have the same cross-sectional shape, which is excellent in productivity. .

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of the catalytic combustor of the present invention,
In this figure, the catalyst carrier 8 is divided along the flow direction M of the air-fuel mixture into, for example, three divided bodies 8b. Spacers 11 sandwiched between the divided bodies 8b are arranged between the divided bodies 8b, and a gap 10 is held between the divided bodies 8b. The spacer 11 is a ring-shaped structure disposed in contact with the heat insulating material 12 that forms the peripheral wall of the combustor 1, and as shown in the plan sectional view of FIG. It has a gas passage 11a extending to (FIG. 1). Above spacer 11
Is made of a heat-resistant cobalt alloy, for example, and has a structure in which two annular plates 11b are connected by a pin 11c.

The other structure is similar to that of the conventional example shown in FIG.
The same parts or corresponding parts are designated by the same reference numerals, and detailed description thereof will be omitted.

In the above structure, the present invention is based on the catalyst carrier 8 of FIG.
Since the gaps 10 are formed between the respective divided bodies 8b constituting the above, the gas is mixed in the gaps 10. Therefore, since the gas concentration distribution becomes uniform, the combustion efficiency is improved.

Further, since the spacer 11 has the gas passage 11a extending in the flow direction M of the air-fuel mixture, it does not block the combustion passage 8a of the outer peripheral portion 8c. Therefore, the gas also flows into the combustion passage 8a of the catalyst carrier outer peripheral portion 8c corresponding to the spacer 11 portion, and catalytic combustion can also be performed in this outer peripheral portion 8c. Therefore, since the temperature difference between the outer peripheral portion 8c and the central portion 8d of the catalyst carrier is small, thermal stress is not generated, and as a result, cracking of the catalyst carrier 8 can be prevented.

Furthermore, the inner cylinder 3 of the combustor 1 can be made into a simple cylindrical shape whose cross-sectional area does not change in the axial direction (vertical direction in FIG. 1), and correspondingly, the catalyst carrier 8 is divided into sections. Since the body 8b can also have the same sectional shape, the productivity is good.

By the way, the shape of the spacer 11 is not limited to that of the above embodiment. For example, as shown in FIG. 3, two annular plates 11b may be joined by a corrugated plate 11d to form the gas passage 11a, or only an annular corrugated plate may be used.

[Advantage of the Invention] As described above, according to the present invention, a gap is maintained between the divided bodies of the catalyst carrier, and the air-fuel mixture is sufficiently mixed in this gap to make the concentration distribution uniform and improve the combustion efficiency. Improvement can be realized. In addition, a ring-shaped spacer sandwiched between the divided bodies to form a gap for exhibiting such a function is provided in a portion of the outer peripheral portion of the catalyst carrier, which corresponds to the combustion passage, in a gas extending in the flow direction of the air-fuel mixture. Since the passage has the passage, the combustion passage in the outer peripheral portion of the catalyst carrier is not blocked by the spacer, and the air-fuel mixture can also flow into the combustion passage in the outer peripheral portion of the catalyst carrier for catalytic combustion. The temperature difference between the outer peripheral portion and the central portion of the carrier can be reduced to prevent the catalyst carrier from cracking due to thermal stress. Furthermore, since the combustor and the catalyst carrier can be formed into a simple cylindrical shape whose diameter and cross-sectional area do not change in the axial direction, the productivity can be improved in terms of shape.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a catalytic combustor showing an embodiment of the present invention, FIG. 2 is a plan sectional view showing a part of a spacer, and FIG. 3 is a plan sectional view showing a modified example of the spacer. FIG. 4 is a schematic vertical sectional view of a conventional catalytic combustor, and FIG. 5 is a longitudinal sectional view of an essential part of a catalytic combustor not included in the present invention. 1 ... Catalyst combustor, 8 ... Catalyst carrier, 8a ... Combustion passage,
8b …… Divided body, 10 …… Gap, 11 …… Spacer, 11a ……
Gas passage, 12 ... Insulation material (peripheral wall of combustor), A ... Air, F ... Fuel, M ... Flow direction of mixture.

Claims (1)

(57) [Scope of utility model registration request] 1. A catalyst carrier, which forms a large number of narrow combustion passages through which a mixture of fuel and air flows, is divided into a plurality of divided bodies along the flow direction of the mixture, and between the divided bodies. Is a catalyst combustor which is in contact with the peripheral wall of the combustor and is sandwiched between the respective divided bodies, and in which a ring-shaped spacer for maintaining a gap is arranged, the spacer corresponds to the combustion passage in the outer peripheral portion of the catalyst carrier. A catalytic combustor formed by a structure having a gas passage extending in the flow direction in a part thereof.