JPH05256163A - Catalytic burner - Google Patents

Abstract

PURPOSE:To raise the temperature of mixture to the catalyst activating temperature or more without using a preburner and a preheater in a gas-turbine engine with a catalytic burner. CONSTITUTION:A combustion gas reflux passage 45 for recirculating combustion gas is provided from the lower reaches to the upper reaches of a catalyst bearing part 43, and a flow control valve 46 is interposed in this combustion gas reflux passage 45. On the basis of the intake air temperature detected by a sensor S1, the combustion gas temperature detected by a sensor S2 and the intake air quantity detected by a sensor S4, the flow control valve 46 is opened/ closed to control the reflux quantity of the combustion gas. Accordingly, even in the case of low intake air temperature at the engine starting time, the low load operation time, and the like, the temperature of mixture is raised to the catalyst activating temperature or more to enable the continuation of combustion. The reflux is stopped when the intake air temperature detected by the sensor S1 and the temperature of the mixture detected by a sensor S3 exceed the catalyst activating temperature.

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.

By the way, since the catalyst does not function unless its temperature exceeds a predetermined catalyst activation temperature (usually about 400 ° C. to 500 ° C.), when the gas turbine engine is started at a normal temperature, It is necessary to raise the temperature of the catalyst or the air-fuel mixture that comes into contact with the catalyst to a temperature above the catalyst activation temperature by some method. for that reason,
It is known that the catalyst is heated by a preburner or a preheater at the time of starting the gas turbine engine, and the temperature of the catalyst is preheated to the catalyst activation temperature or higher to start the engine (for example,
(See Japanese Examined Patent Publication No. 1-38215).

[0004]

Generally, in the catalytic combustion type gas turbine engine, after the air-fuel mixture starts combustion and enters a steady operation state, the combustion causes the catalyst temperature or the air-fuel mixture temperature to become catalytically active. Since the temperature is kept above the activation temperature, the operation of the engine is continued even if the operation of the preburner or the preheater is stopped. However, during low load operation of the engine or in the case of low pressure ratio engine,
There is a problem that the catalyst temperature or the air-fuel mixture temperature cannot be maintained above the catalyst activation temperature during the operation, and the operation cannot be continued unless the preburner or the preheater is operated.

However, when the preburner is used, the catalyst temperature locally rises and the NO _x emission increases, so that the characteristic of the catalytic combustion system that the NO _x emission is small cannot be fully utilized, and the preheater is used. If used, problems such as deterioration of the catalyst and increase in power consumption will occur.

The present invention has been made in view of the above circumstances, and in a catalytic combustor, the mixture temperature is kept above the catalyst activation temperature without using a preburner or a preheater at the time of starting or low load operation. The purpose is to

[0007]

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. The first feature is that a combustion gas recirculation passage for guiding a part of the combustion gas from the downstream side to the upstream side of the catalyst supporting portion and a combustion gas recirculation amount control means provided in the combustion gas recirculation passage are provided.

In addition to the above first feature, the present invention also provides
A catalyst combustor inlet temperature sensor for detecting the inlet temperature of the catalyst combustor is provided, and the combustion gas recirculation amount control means recirculates the combustion gas when the temperature detected by the catalyst combustor inlet temperature sensor is below a predetermined value. Is the second feature.

The present invention, in addition to the above-mentioned first feature,
A catalyst carrier inlet temperature sensor for detecting the inlet temperature of the catalyst carrier is provided, and when the temperature detected by the catalyst carrier inlet temperature sensor is below a predetermined value, the combustion gas recirculation amount control means recirculates the combustion gas. Is the third feature.

In addition to the above-mentioned first feature, the present invention also provides:
A catalytic combustor inlet temperature sensor that detects the catalytic combustor inlet temperature, a catalytic combustor outlet temperature sensor that detects the catalytic combustor outlet temperature, and a catalytic combustor inlet air amount that detects the catalytic combustor inlet air amount. A sensor, and the combustion gas recirculation amount control means determines the recirculation amount of the combustion gas based on the outputs of the catalyst combustor inlet temperature sensor, the catalyst combustor outlet temperature sensor, and the catalyst combustor inlet air amount sensor. This is the fourth feature.

In addition to the above-mentioned first feature, the present invention also provides:
The catalyst combustor inlet temperature sensor for detecting the inlet temperature of the catalyst combustor and the catalyst supporting portion inlet temperature sensor for detecting the inlet temperature of the catalyst supporting portion are provided, and the catalyst combustor inlet temperature sensor and the catalyst supporting portion inlet temperature sensor are provided. A fifth feature is that the combustion gas recirculation amount control means stops the recirculation of the combustion gas when the temperatures detected in each are above a predetermined value.

[0012]

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

1 to 5 show an 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. FIG. 4 is an enlarged sectional view of an essential part, FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 3, and FIG.

As shown in FIGS. 1 and 2, a two-shaft type 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 in front of and behind the central opening formed in the outer casing 1. In addition, an axial low-pressure turbine 11 for taking out an output is arranged behind the high-pressure turbine 10 and 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 includes 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 arranged 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.

A circular arc-shaped 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 portion 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 supporting surface formed on the front portion of the ring gear 36 is provided with 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, on the upstream side of the casing 42 of the catalytic combustor 12, a plurality of hot air which has passed through the heat exchanger 13 and is heated is introduced into the catalytic combustor 12. The air inlet 42 ₁ is formed, and on the downstream side of the casing 42, a catalyst supporting portion 43 and a fuel nozzle 44 for spraying fuel toward the catalyst supporting portion 43 are arranged. An upstream side and a downstream side of the catalyst supporting portion 43 are connected by a combustion gas recirculation passage 45, and a part of the combustion gas generated by the combustion of the air-fuel mixture in the catalyst supporting portion 43 passes through the combustion gas recirculation passage 45 and the catalyst supporting portion 43. Reflux upstream of 43. The combustion gas recirculation passage 45 is provided with a flow rate control valve 46 for controlling the recirculation amount of the combustion gas. At the upstream end of the casing 42, the gas turbine engine G
A fuel nozzle 49 for supplying fuel and a spark plug 47 for igniting the air-fuel mixture are provided at the time of starting.

A catalyst combustor inlet temperature sensor S ₁ for detecting the temperature of intake air introduced into the catalyst combustor 12 is provided near the air inlet 42 ₁ of the casing 42, and near the downstream end of the casing 42. The catalytic combustor 12
A catalytic combustor outlet temperature sensor S ₂ is provided for detecting the temperature of the combustion gas flowing out of the catalytic combustor. Further, upstream of the catalyst carrier 43, a catalyst carrier inlet temperature sensor S ₃ for detecting the temperature of the air-fuel mixture supplied to the catalyst carrier 43 is provided. Furthermore, the air inlet 42 ₁ has a catalytic combustor 12
A catalytic combustor inlet air amount sensor S ₄ is provided for detecting the flow rate of intake air introduced into the. Then, the opening degree of the flow rate control valve 46 provided in the combustion gas recirculation passage 45 is controlled based on the output signals of the sensors S _{1 to} S ₄ .

As shown in FIG. 4, the catalyst supporting portion 43 is formed in the shape of a honeycomb, and the catalyst 48 is formed on the surface in contact with the air-fuel mixture.
Are carried. As the catalyst 48, noble metal-based catalysts and non-noble metal-based catalysts can be used, and Pt, Pt-Ir, Pt-Pd, Pt-NiO, Pt- can be used as the noble metal-based catalyst.
_{Co 2 O 2, Pt-Pd} -NiO, there is Pt-Ag, etc., and MnO ₂ as the non-noble metal catalyst, Co
₂ O ₂ , Co ₂ O ₄ , CuO and the like.

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

When the gas turbine engine G is in a normal operating state, the air that has passed through the air cleaner 4 and the silencer 5 and has flowed into the intake passage 6 is compressed to a high temperature and high pressure by the compressor rotor 17 disposed inside the compressor casing 15. , Is sent rearward through a radial air passage 19 formed between the outer casing 1 and the inner casing 18. 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 has been heated to a higher temperature in this way passes through the opening 29 ₁ formed in the upper portion of the collector housing 29 and the inner casing 1
8 flows into the internal space.

The intake air supplied to the inner space of the inner casing 18 is introduced from the air inlet 42 ₁ into the inside of the catalytic combustor 12, where it is mixed with the fuel supplied from the fuel nozzle 44 and is mixed in the catalyst supporting portion 43. It flows in, contacts the catalyst 48, and burns. Combustion gas generated by the combustion of the air-fuel mixture flows into the scroll 24 from the transient duct 23, and then is blown to the high-pressure turbine rotor 20 through the six nozzle vanes 25.

When the high-pressure turbine rotor 20 rotates in this way, 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.

By the way, since the heat exchanger 13 is in a low temperature state at the time of starting the gas turbine engine G, the temperature of the air-fuel mixture supplied to the catalyst supporting portion 43 of the catalyst combustor 12 should be maintained above the catalyst activation temperature. Not possible, catalytic combustor 1
In 2, it is impossible to continue the combustion of the air-fuel mixture. Therefore, at the time of start-up, a part of the combustion gas is recirculated to the upstream side of the catalyst carrier 43 through the combustion gas recirculation passage 45, and the heat is used to heat the air-fuel mixture supplied to the catalyst carrier 43 to continue combustion. It has become.

This will be further described with reference to the flowchart of FIG. First, in step 1, the air-fuel mixture is ignited by the spark plug 47 to start the gas turbine engine G, and in step 2, is the temperature of the intake air detected by the catalyst combustor inlet temperature sensor S ₁ equal to or higher than the catalyst activation temperature? Determine whether or not.
Immediately after the start-up, the temperature of the intake air is low and below the catalyst activation temperature.
_The required return of the combustion gas based on the temperature of the intake air detected in ₁ , the temperature of the combustion gas detected by the catalyst combustor outlet temperature sensor S ₂ , and the intake air amount detected by the catalyst combustor inlet air amount sensor S _4. The flow rate is calculated, and the flow rate control valve 46 is controlled so as to obtain the recirculation amount, so that the combustion gas is recirculated to the upstream side of the catalyst carrier 43. As a result, the catalyst carrier 43
The air-fuel mixture supplied to is heated above the catalyst activation temperature,
The air-fuel mixture can continue combustion in a stable state.

As described above, the warm-up of the heat exchanger 13 is completed while the combustion of the air-fuel mixture is continued by the recirculation of the combustion gas, and the temperature of the air-fuel mixture detected by the catalyst carrier inlet temperature sensor S ₃ in step 4 is reached. Is equal to or higher than the catalyst activation temperature and the temperature of the intake air detected by the catalyst combustor inlet temperature sensor S ₁ in step 2 is equal to or higher than the catalyst activation temperature, the combustion of the air-fuel mixture is continued without recirculating the combustion gas. Therefore, in step 5, the flow rate control valve 46 is closed to stop the reflux.

In the high pressure ratio gas turbine engine G provided with the heat exchanger 13 as in the above embodiment, the intake air supplied to the catalytic combustor 12 and the air-fuel mixture supplied to the catalyst carrier 43 are mixed. Since there is no great difference in temperature, the catalyst combustor inlet temperature sensor S ₁ and the catalyst supporting portion inlet temperature sensor S ₃
Can substitute the other for either one.

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, the gas turbine engine G provided with the heat exchanger 13 is illustrated in the embodiment, but the present invention is also applicable to an engine having a low pressure ratio not provided with the heat exchanger. In this case, not only the combustion gas is recirculated at the time of start-up, but also the combustion gas is recirculated as necessary during the normal operation, so that the combustion of the air-fuel mixture can be continued in a stable state.

[0034]

As described above, according to the first feature of the present invention, a part of the combustion gas is recirculated from the downstream side of the catalyst supporting portion to the upstream side through the combustion gas recirculation passage, and the combustion gas is recirculated. Is controlled by the combustion gas recirculation amount control means provided in the combustion gas recirculation passage, so that once the combustion of the air-fuel mixture is started, the temperature of the air-fuel mixture is maintained at the catalyst activation temperature or higher by the combustion gas. be able to. As a result, a preburner and a preheater are not required after the start of operation, and it is possible to reduce the amount of NO _x generated, prevent catalyst deterioration, and save heating power.

According to the second aspect of the present invention, the combustion gas recirculation amount control means recirculates the combustion gas when the temperature detected by the catalyst combustor inlet temperature sensor is equal to or lower than a predetermined value.
The air-fuel mixture temperature can be maintained above the catalyst activation temperature with the minimum necessary amount of reflux.

Further, according to the third feature of the present invention, the combustion gas recirculation amount control means recirculates the combustion gas when the temperature detected by the catalyst carrier inlet temperature sensor is equal to or lower than a predetermined value.
The air-fuel mixture temperature can be maintained above the catalyst activation temperature with the minimum necessary amount of reflux.

According to a fourth aspect of the present invention, the combustion gas recirculation amount control means is based on the outputs of the catalytic combustor inlet temperature sensor, the catalytic combustor outlet temperature sensor, and the catalytic combustor inlet air amount sensor. Determines the recirculation amount of the combustion gas, so that the mixture temperature can be finely controlled and maintained at the optimum temperature.

According to the fifth aspect of the present invention, the combustion gas recirculation amount control means recirculates the combustion gas when the temperatures detected by the catalyst combustor inlet temperature sensor and the catalyst supporting portion inlet temperature sensor are above predetermined values. Since this is stopped, it is possible to prevent the catalyst temperature from excessively rising due to the recirculation of the combustion gas.

[Brief description of drawings]

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.

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 flowchart explaining the operation.

[Explanation of symbols]

12 catalyst combustor 43 catalyst support part 45 combustion gas recirculation passage 46 flow control valve (combustion gas recirculation amount control means) S ₁ catalyst combustor inlet temperature sensor S ₂ catalyst combustor outlet temperature sensor S ₃ catalyst support part inlet temperature sensor S ₄ Catalyst combustor inlet air amount sensor

Claims (5)

[Claims] 1. A catalyst supporting portion (4) of a catalyst combustor (12).
In a catalytic combustor in which a mixture of fuel and air is brought into contact with a catalyst carried in 3) to burn, a combustion gas recirculation passage (45) for guiding a part of combustion gas from a downstream side to an upstream side of the catalyst carrying section (43). And a combustion gas recirculation amount control means (4) provided in the combustion gas recirculation passage (45).
6) A catalytic combustor comprising: 2. A catalytic combustor (12) comprises a catalytic combustor inlet temperature sensor for detecting the inlet temperature of (S _1), the temperature detected by the catalytic combustor inlet temperature sensor (S ₁₎ is equal to or less than a predetermined value The catalytic combustor according to claim 1, characterized in that the combustion gas recirculation amount control means (46) sometimes recirculates the combustion gas. 3. A catalyst supporting portion (43) provided with a catalyst carrier part inlet temperature sensor for detecting (S ₃₎ the inlet temperature, the temperature detected by the catalyst-carrying unit inlet temperature sensor (S ₃₎ is equal to or less than a predetermined value The catalytic combustor according to claim 1, characterized in that the combustion gas recirculation amount control means (46) sometimes recirculates the combustion gas. 4. Detecting the inlet temperature of the catalytic combustor (12)
Catalyst combustor inlet temperature sensor (S₁) And a catalytic combustor
(12) Catalyst combustor outlet temperature sensor for detecting outlet temperature
S (S₂) And the inlet air amount of the catalytic combustor (12) are detected.
Catalyst combustor inlet air amount sensor (S_Four) And
These catalytic combustor inlet temperature sensors (S₁), Catalytic combustor out
Mouth temperature sensor (S₂), And the catalytic combustor inlet air amount
Sensor (S _Four) Output of the combustion gas based on
The control means (46) determines the recirculation amount of the combustion gas.
The catalytic combustor according to claim 1, characterized in that: 5. A catalyst combustor inlet temperature sensor (S ₁ ) for detecting the inlet temperature of the catalyst combustor (12) and a catalyst supporting portion inlet temperature sensor (S ₃ for detecting the inlet temperature of the catalyst supporting portion (43). ) And the temperature detected by the catalyst combustor inlet temperature sensor (S ₁ ) and the catalyst supporting portion inlet temperature sensor (S ₃ ) are respectively above a predetermined value, the combustion gas recirculation amount control means (46) The catalytic combustor according to claim 1, wherein the circulation of the combustion gas is stopped.