JPH05256165A - Catalytic burner - Google Patents

Abstract

PURPOSE:To perform stable combustion without causing the increase of pressure loss in various load regions in a burner for an gas-turbine engine of a catalytic combustion system. CONSTITUTION:A small diameter part 42 positioned upstream of a catalytic burner 12 is provided with a catalyst bearing part 44 of small passage cross-sectional, area, and a large diameter part 43 positioned downstream of the catalytic burner 12 is provided with a catalyst bearing part 45 of large passage cross-sectional area. Fuel nozzles 46, 47 are then disposed in correspondence with both catalyst bearing parts 44, 45. At the time of low load operation, fuel is injected from the upstream fuel nozzle 46 so as to be mixed with intake air taken in from an air lead-in port 423 and burnt being brought into contact with a catalyst at the catalyst bearing part 44 of small passage cross-sectional area. At the time of high load operation, fuel is injected from the downstream fuel nozzle 47 so as to be mixed with intake air taken in from the air lead-in port 421 and burnt being brought into contact with a catalyst at the catalyst bearing part 45 of large passage cross-sectional area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst combustor which causes a mixture of fuel and air to come into contact with a catalyst carried by a catalyst supporting portion of the catalyst combustor to burn the catalyst.

[0002]

2. Description of the Related Art As in a reciprocating engine, a gas turbine engine produces harmful nitrogen oxides (hereinafter referred to as NO _X ) in the exhaust gas, and the NO _X emission amount increases as the combustion temperature of the air-fuel mixture increases. To do. In the conventional combustor for a gas turbine engine, since the combustion temperature of the air-fuel mixture reaches an extremely high temperature (for example, 2000 ° C), it has been difficult to reduce the NO _X emission amount. Therefore, a combustor for a gas turbine engine of a so-called catalytic combustion system has been proposed, in which the air-fuel mixture is brought into contact with a catalyst provided inside the combustor and burned. According to the catalytic combustion method, since the combustion of the mixture in the combustor is relatively carried out at low temperatures, it is possible to significantly reduce the NO _X in the exhaust gas.

In the above-mentioned catalytic combustion type gas turbine engine combustor, a plurality of catalyst supporting portions are arranged in series inside the catalyst combustor, and the flow passage cross-sectional areas of the catalyst supporting portions are changed from upstream to downstream. The one formed so as to become gradually smaller as it shifts to the one on the side is disclosed in JP-A-63-2137.
It is known from Japanese Patent Publication No. 23. According to this catalytic combustor, since the flow velocity of the air-fuel mixture in each catalyst supporting portion is different,
It is possible to select a catalyst supporting portion in which the flow rate of the air-fuel mixture is appropriate according to the operating state of the engine, and burn the air-fuel mixture in a stable state in the catalyst supporting portion.

[0004]

However, the above-described conventional gas turbine engine combustor is formed so that the flow passage cross-sectional areas of the plurality of catalyst carrying portions gradually decrease from the upstream side to the downstream side. Therefore, the combustion gas generated by the combustion of the fuel in contact with the catalyst in the upstream catalyst supporting portion always passes through the downstream catalyst supporting portion having a small flow passage cross-sectional area. As a result, there is a problem that the pressure loss in the catalytic combustor increases and the output of the engine is adversely affected.

The present invention has been made in view of the above circumstances, and an object thereof is to perform stable combustion in various load regions of a gas turbine engine without increasing pressure loss in the catalytic combustor. To do.

[0006]

In order to achieve the above object, the present invention provides a catalytic combustor in which a mixture of fuel and air is brought into contact with a catalyst carried by a catalyst supporting portion of the catalyst combustor to burn the catalyst. A plurality of catalyst supporting portions which are arranged in series along the direction of the air flow flowing through the catalytic combustor, and whose flow passage cross-sectional areas gradually increase from upstream to downstream. A plurality of catalyst supporting portions are provided corresponding to each of the catalyst supporting portions, and fuel is supplied to the catalyst supporting portion having a small flow passage cross-sectional area during low load operation, and to the catalyst supporting portion having a large flow passage cross sectional area during high load operation. The first feature is that a plurality of fuel nozzles for supplying fuel are provided.

In addition to the first feature described above, the present invention also provides
A second feature is that an air inlet is provided upstream of each catalyst supporting portion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment of the present invention. FIG. 1 is a vertical sectional view of a gas turbine engine, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is FIG. An enlarged cross-sectional view of the main part of
FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG.

As shown in FIGS. 1 and 2, a two-shaft gas turbine engine G has a bottomed cylindrical outer casing 1 and an annular heat exchanger housing 2 connected to a rear opening of the outer casing 1. And an exhaust housing 3 that covers the rear part of the heat exchanger housing 2. An intake passage 6 having an air cleaner 4 and a silencer 5 is connected to the front portion of the outer casing 1, a reduction gear box 7 is arranged at the center of the exhaust housing 3, and a lower portion of the exhaust housing 3 is provided. The exhaust duct 8 is connected.

A centrifugal compressor 9 for compressing the air sucked from the intake passage 6 and a centrifugal high-pressure turbine 10 for driving the compressor 9 are arranged before and after the central opening formed in the outer casing 1. In addition, an axial flow type low pressure turbine 11 for taking out the output is arranged behind the high pressure turbine 10 and a combustion gas for driving the low pressure turbine 11 in the upper space of the outer casing 1. A catalytic combustor 12 for generating is disposed. A cylindrical combustor housing 41 is fixed to the outer casing 1 so as to penetrate therethrough (see FIG. 2), and the catalytic combustor 12 is detachably mounted from the outside of the outer casing 1 via the combustor housing 41. .. Further, inside the heat exchanger housing 2, the two turbines 10,
An annular heat exchanger 13 for recovering the heat energy of the exhaust gas that has passed through 11 and heating the intake air is arranged so as to surround the speed reducer box 7 and the inside of the speed reducer box 7. A planetary gear type speed reducer 14 that decelerates the output of the low-pressure turbine 11 and takes it out is disposed therein.

A high-pressure turbine shaft 16 is rotatably supported at the center of a compressor casing 15 provided in the outer casing 1, and a compressor rotor 17 having a large number of blades on its outer periphery is fixed to the high-pressure turbine shaft 16. It The air sucked into the compressor casing 15 from the intake passage 6 is compressed by the compressor rotor 17 and is supplied rearward through a radial air passage 19 formed between the outer casing 1 and the inner casing 18. .. The front end of the high-pressure turbine shaft 16 is connected to auxiliary equipment such as a generator and a starter housed in an auxiliary equipment housing (not shown).

A high pressure turbine rotor 20 having a large number of blades formed on its outer periphery is fixed to the rear end of the high pressure turbine shaft 16, and the high pressure turbine rotor 20 has a back plate 21.
And the high pressure turbine shroud 22. A scroll 24, which is connected to the catalytic combustor 12 via a transient duct 23, is also provided outside the high-pressure turbine shroud 22, and a plurality of scrolls are provided between the inner periphery of the scroll 24 and the outer periphery of the high-pressure turbine rotor 20. Nozzle vanes 25 are provided. The scroll 24 is supported from the outer periphery by a plurality of support mechanisms 26, and the transient duct 23 is supported by other support mechanisms 27 and 28.

A collector housing 29 is provided at the front end of the heat exchanger housing 2 connected to the rear portion of the outer casing 1.
Is supported, and the low-pressure turbine shaft 30 is supported in the center thereof. A low pressure turbine rotor 31 is fixed to the tip of the low pressure turbine shaft 30, and a large number of blades formed on the outer periphery of the low pressure turbine rotor 31 are fitted to the inner surface of the low pressure turbine shroud 32. The low pressure turbine shroud 32 and the high pressure turbine shroud 22 are connected by a low pressure turbine duct 34 having a variable vane 33 at the rear end. The low-pressure turbine shaft 30 is connected to the output shaft 35 via the speed reducer 14.

An arcuate opening 29 ₁ is formed in the upper half of the collector housing 29, and the heat exchanger 1 is assembled from the air passage 19 to the upper part of the exhaust housing 3.
The air that has been heated by passing through the upper half of
It is supplied to the inside of the inner casing 18 via ₁ .
On the other hand, in the lower half of the collector housing 29, the exhaust gas that has passed through the low-pressure turbine shroud 32 is placed in the heat exchanger 13.
An exhaust gas passage 29 ₂ for leading to the lower half portion is formed.

A ring gear 36 is mounted on the outer circumference of the heat exchanger 13 over 360 °, and a flat support surface formed on the front portion of the ring gear 36 has a plurality of guide rollers provided on the inner circumference of the heat exchanger housing 2. It is rotatably supported by 37. A pinion 39 that meshes with the ring gear 36 is fixed to a rotary shaft 38 that supports one guide roller 37, and the heat exchanger 13 is rotated by rotating the rotary shaft 38 by a heat exchanger drive motor 40. It

As shown in FIG. 3, the catalytic combustor 12 has a small diameter portion 42 on the upstream side and a large diameter portion 43 on the downstream side, and the end of the large diameter portion 43 is connected to the transient duct 23. A plurality of air introduction ports 42 ₁ for introducing high temperature air, which has passed through the heat exchanger 13 and heated, into the catalytic combustor 12 is formed on the outer periphery of the small diameter portion 42. Small diameter part 42
The large diameter portion 43 is provided with catalyst carrying portions 44 and 45, respectively, and the fuel nozzles 46 and 47 are provided upstream of the catalyst carrying portions 44 and 45, respectively. Downstream catalyst carrier 45
The cross-sectional area of the channel is larger than the cross-sectional area of the catalyst supporting portion 44 on the upstream side. At the upstream end of the small diameter portion 42, a fuel nozzle 51 for supplying fuel and a spark plug 48 for igniting the air-fuel mixture when the gas turbine engine G is started are provided.

As shown in FIG. 4, the catalyst carrier 4 on the downstream side
The numeral 5 is formed in a honeycomb shape, and the catalyst 49 is carried on the surface in contact with the air-fuel mixture. As the catalyst 49, noble metal-based catalysts and non-noble metal-based catalysts can be used, and Pt, Pt—Ir, Pt—Pd, Pt—Ni can be used as the noble metal catalysts.
_{O, Pt-Co 2 O 2} , Pt-Pd-NiO, Pt-A
g, etc., and as a non-precious metal type catalyst, MnO ₂ , C
There are o ₂ O ₂ , Co ₂ O ₄ , CuO and the like. The structure of the upstream catalyst support portion 44 is the same as that described above, and only the flow passage cross-sectional area is different.

Next, the operation of the embodiment of the present invention having the above construction will be described.

The air that has passed through the air cleaner 4 and the silencer 5 and has flowed into the intake passage 6 is compressed into high temperature and high pressure by the compressor rotor 17 disposed inside the compressor casing 15, and is formed between the outer casing 1 and the inner casing 18. It is sent to the rear via a radial air passage 19. The intake air that has reached the inside of the exhaust housing 3 from the air passage 19 gathers in the upper space of the exhaust housing 3 and then turns to the front to move the upper half of the core surface of the rotary heat exchanger 13 to the front side. Pass from the back to the front. The air that has passed through the heat exchanger 13 and is heated to a higher temperature in this way flows into the inner space of the inner casing 18 through the opening 29 ₁ formed in the upper portion of the collector housing 29.

The intake air supplied to the inner space of the inner casing 18 is supplied from the air inlet 42 ₁ to the catalytic combustor 12
Is introduced into the small diameter portion 42 of the. During low load operation, fuel is supplied from the fuel nozzle 46 on the upstream side, and the air-fuel mixture in which the fuel and high temperature air are mixed flows into the catalyst carrier 44 on the upstream side, where it comes into contact with the catalyst 49 and burns. The combustion gas generated by the combustion of the air-fuel mixture flows into the large-diameter portion 43 of the catalyst combustor 12, passes through the downstream catalyst support portion 45 provided therein, and flows into the transient duct 23. The combustion gas further flows into the scroll 24, from which it is sprayed onto the high-pressure turbine rotor 20 through the six nozzle vanes 25.

When the high-pressure turbine rotor 20 rotates in this manner, the driving force thereof causes the compressor rotor 17 provided on the high-pressure turbine shaft 16 to rotate. The combustion gas that has passed through the high-pressure turbine rotor 20 is blown onto the low-pressure turbine rotor 31 via the low-pressure turbine duct 34 and the variable vanes 33, and rotationally drives the low-pressure turbine shaft 30. The rotation of the low-pressure turbine shaft 30 is decelerated by the speed reducer 14 and taken out from the output shaft 35. After the exhaust gas passing through the low-pressure turbine rotor 31 is collected by the exhaust gas passage 29 ₂ formed in the lower portion of the collector housing 29, it passes from the front lower half of the core surface of the rotary heat exchanger 13 back To heat the heat exchanger 13,
It is discharged to the exhaust duct 8. The heat exchanger 13 thus heated by the exhaust gas is rotationally driven by the heat exchanger drive motor 40 via the pinion 39 and the ring gear 36, and the heated core surface sequentially faces the passage of the intake air. To heat the intake air.

During high load operation, the fuel nozzle 47 on the downstream side
Fuel is supplied from. Therefore, the air inlet 42 ₁
The high-temperature air introduced into the small-diameter portion 42 of the catalytic combustor 12 from the above reaches the large-diameter portion 43 without passing through the catalyst supporting portion 44 on the upstream side, and is mixed with the fuel from the fuel nozzle 47. The air-fuel mixture flows into the catalyst supporting portion 45 on the downstream side, where the catalyst 49
Burns in contact with.

As described above, the air-fuel mixture is burned in the upstream catalyst carrying portion 44 during the low load operation, and the air-fuel mixture is burned in the downstream catalyst carrying portion 45 during the high load operation. The pressure loss in the catalytic combustor 12 can be reduced. That is, since a relatively small amount of combustion gas is generated in the upstream catalyst support portion 44 during low load operation, when the combustion gas passes through the downstream catalyst support portion 45 having a sufficiently large flow passage cross-sectional area. The pressure loss of is very small. On the other hand, since the amount of intake air passing through the upstream catalyst support portion 44 during high load operation is much smaller than the amount of combustion gas, the pressure loss in the upstream catalyst support portion 44 is also small. Becomes

Further, at the time of low load operation, the amount of the air-fuel mixture generated is small because the amount of intake air introduced into the catalyst combustor 12 is small, but the catalyst carrier 4 on the upstream side where the air-fuel mixture burns.
The cross-sectional area of the flow path of No. 4 also becomes small in proportion to the amount of the air-fuel mixture.
On the other hand, during high load operation, the amount of intake air introduced into the catalytic combustor 12 is large, so the amount of air-fuel mixture generated is also large,
The flow passage cross-sectional area of the catalyst supporting portion 45 on the downstream side where the air-fuel mixture burns also increases in proportion to the air-fuel mixture amount. Therefore, in both cases of low load operation and high load operation, the flow velocity and air-fuel ratio of the air-fuel mixture passing through both catalyst supporting portions 44, 45 are maintained at appropriate values, and stable combustion performance is secured. It becomes possible.

FIG. 5 shows a second embodiment of the present invention.
The catalyst combustor 12 of this embodiment has an air inlet 43 ₁ corresponding to the downstream side catalyst carrying portion 45 provided in the large diameter portion 43.
Equipped with. The air inlet 43 ₁ is slidably supported on the outer circumference of the large diameter portion 43 and is opened and closed by a ring-shaped shutter 50 driven by an actuator (not shown).

Thus, during a low load operation in which the air-fuel mixture is burned in the upstream catalyst carrier 44, the shutter 50 is closed and the same operation as in the first embodiment is performed. During high-load operation, the shutter 50 is opened, and the intake air does not pass through the air introduction port 42 ₁ of the small diameter portion 42 but directly flows from the air introduction port 43 ₁ of the large diameter portion 43 to the catalyst carrying portion 45 on the downstream side. Supplied. This eliminates the need for the intake air to pass through the upstream catalyst support portion 44, so that the pressure loss in the catalyst support portion 44 can be avoided.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various small design changes can be made.

For example, in the embodiment, two catalyst supporting parts 4 are used.
Although 4, 45 are provided in series, it is also possible to provide three or more catalyst supporting portions in series.

[0030]

As described above, according to the first feature of the present invention, at the time of low load operation with a small air flow rate, fuel is supplied to the catalyst supporting portion provided on the upstream side and having a small flow passage cross-sectional area for combustion. During high-load operation with a large air flow rate, the fuel is supplied to the catalyst-supporting portion with a large flow passage cross-sectional area provided on the downstream side to burn the catalyst-supporting portion. It is possible to make the fuel ratio uniform and perform stable combustion. Moreover, since the flow passage cross-sectional area of the downstream catalyst support portion through which the combustion gas passes is formed larger than the flow passage cross-sectional area of the upstream catalyst support portion, the pressure loss in the catalyst combustor should be minimized. You can

Further, according to the second aspect of the present invention, since the air inlets are provided upstream of the respective catalyst supporting portions, the air is directly introduced into the catalyst supporting portion to which the fuel is supplied, so that the air is introduced upstream. It is possible to avoid pressure loss in the side catalytic combustor.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a gas turbine engine according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is an enlarged cross-sectional view of the main part of FIG.

4 is an enlarged sectional view taken along line 4-4 of FIG.

FIG. 5 is a diagram corresponding to FIG. 3 according to a second embodiment of the present invention.

[Description of Reference Signs] 12 catalyst combustor 42 ₁ air inlet 43 ₁ air inlet 44 catalyst carrier 45 catalyst carrier 46 fuel nozzle 47 fuel nozzle 49 catalyst

Claims (2)

[Claims] 1. A catalyst supporting portion (4) of a catalyst combustor (12).
A catalyst combustor in which a mixture of fuel and air is brought into contact with a catalyst (49) carried on a catalyst (4, 45) to burn, the catalyst combustors (12) being arranged in series along a direction of an air flow flowing through the catalyst combustor (12). , A plurality of catalyst supporting parts (44, 45) formed so that their flow passage cross-sectional areas gradually increase from upstream side to downstream side, and the plurality of catalyst supporting parts (44, 45) Fuel is supplied to the catalyst carrying portion (44) having a small flow passage cross-sectional area, which is provided corresponding to each other, at the time of low load operation, and fuel is supplied to the catalyst carrying portion (45) having a large flow passage cross-sectional area during high load operation. A catalytic combustor comprising a plurality of fuel nozzles (46, 47) for supplying. 2. The catalytic combustor according to claim ₁ , wherein air inlets (42 ₁ , 43 ₁ ) are provided upstream of each of the catalyst supporting parts (44, 45).