JP2774557B2 - Combustor for catalytic combustion type gas turbine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas turbine combustor. More specifically, the present invention relates to a gas turbine combustor using both catalytic combustion and premixed combustion.

(Prior Art) In a gas turbine combustor, it is demanded to increase the combustion gas temperature at the combustor outlet while reducing NOx in consideration of thermal efficiency and environmental pollution in a power generation system. On the other hand, catalytic combustion has been conventionally proposed as one of the prominent methods of low NOx combustion, but a high temperature, for example, about 1300 ° C. combustion gas is obtained while maintaining low NOx properties in relation to the heat resistant temperature of the catalyst. It is difficult. Therefore, it has been considered to increase the temperature of the combustion gas at the outlet of the combustor while maintaining the catalyst temperature at or below the heat-resistant temperature of the catalyst by combining the catalytic combustion and the gas phase combustion to prevent the catalyst from deteriorating.

As such a combustor, Japanese Patent Laid-Open No. 60-175925 proposes a system in which a gas phase combustion zone is provided downstream of a catalyst layer, and fuel is added to high-temperature gas produced by catalytic combustion to perform diffusion combustion. This combustion method uses a nozzle 10 as shown in FIG.
The fuel injected from 3 is pre-burned to generate a combustion gas preheated to a temperature required for catalytic combustion, and the combustion gas is catalyzed by the catalyst 101, while a pipe 102 penetrating through the catalyst 101 is generated.
Auxiliary fuel is injected into the outlet portion of the catalyst 101 to increase the fuel concentration to diffuse and burn the flame-retardant fuel, thereby raising the temperature of the combustion gas.

(Problems to be Solved by the Invention) However, since the entire surface of the combustion chamber is closed with a single catalyst 101, a large-sized catalyst is required when manufacturing a large-sized combustor. However, large catalysts are disadvantageous in that their production is difficult and their reliability is significantly impaired due to thermal stress and the like, and it is said that it is currently difficult to commercialize them industrially. Moreover, it is economically quite expensive.

In addition, since the combustor in FIG. 7 performs diffusion combustion downstream of the catalyst outlet, the effect of the increase in NOx due to the diffusion combustion cannot be suppressed, and the gas temperature at the combustor outlet is reduced while the catalyst combustion temperature is kept low. In the case of trying to increase it, there is a problem that the NOx reduction effect is reduced.

An object of the present invention is to provide a large-sized combustor for a gas turbine with high reliability and low NOx using a small catalyst which has already been industrially put into practical use.

(Means for Solving the Problems) In order to achieve the object, a combustor for a catalytic combustion gas turbine according to the present invention includes a premixer segment having a built-in premixer, a catalyst filled therein and an upstream side thereof. A catalyst segment containing a premixer is arranged in parallel and assembled, and the assembly forms a large combustor in which the premixed gas from the premixer segment is burned by the combustion gas from the catalyst segment. I have.

(Action) Accordingly, while the catalyst is burned while maintaining the catalyst temperature, the catalyst inlet flow rate, and the like at optimal conditions for the catalyst, the premixed gas that is leaner than the normal premixed gas around or inside the high-temperature combustion gas injected from the catalyst. To stably combust the premixed gas whose combustion is unstable by using high temperature gas as a fire, and suppress the generation of NOx by the effects of catalytic combustion and lean premixed combustion. Further, by adjusting the concentration of the premixed gas injected from the premixer segment, the combustor outlet temperature of the combustion gas can be raised to a temperature higher than the catalyst heat-resistant temperature. The size of the catalyst is determined by the number and size of the catalyst segments regardless of the size of the combustor, and the size can be reduced to an optimum size.

Further, since a burner is constituted by an aggregate of segments, catalysts and other parts are exchanged by exchanging segments, and gas turbines of various sizes, large and small, are constituted by increasing or decreasing the number of segments.

(Examples) Hereinafter, the configuration of the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 is a central longitudinal sectional view showing a schematic structure of a combustor for a catalytic combustion type gas turbine of the present invention. In this catalytic combustion type gas turbine combustor, a premixer segment 4 containing a premixer 7 and a catalyst segment 3 filled with a small catalyst 5 and having a premixer 6 built in parallel are arranged in parallel. And a large burner 1 is constituted by the assembly. The combustor usually has a double cylinder structure of a casing 11 and a liner 12, an air flow path 13 is formed between the liner 12 and the casing 11, and the compressed air A supplied from the gas turbine side is formed. The premixer segment 4 is provided in the combustion chamber 2 inside the liner 12 so as to be injected from the catalyst segment 3 and the liner cooling air hole 14, respectively. Also,
If the liner 12 is provided with a secondary air hole, the air A is also injected therefrom.

The premixer segment 4 is provided with a premixer 7 therein, and has a predetermined air ratio, such as the catalyst segment 3 during rated operation.
The premixed gas supplied to the combustion chamber is slightly richer than the premixed gas supplied into the combustion chamber, but is thinner than the premixed gas concentration in a normal premixed combustor. The premixer 7 is composed of, for example, a venturi tube 15 and a fuel injection nozzle 10 as shown in FIG. 3 (A), sucks combustion air A around the nozzle 10 by an ejector effect, and It is provided to obtain a premixed gas. As shown in FIG. 3 (B), the premixer segment 4 is provided with a swirler 16 at the outlet so that the premixed gas is swirled and injected into the combustion chamber 2. It is also possible to enhance the diffusion mixing with the combustion gas injected from the fuel gas 3. Further, as shown in FIG. 3 (C), an igniter 17 may be provided at the outlet of the segment 4 to operate as a premix burner when the gas turbine is started. In this case, the combustion air A is sucked by the ejector effect of the fuel F injected from the combustion injection nozzle 10 by an adjusting valve (not shown) or the like at the time of starting with low air pressure and at the time of partial load, for example, at the time of 20% load. Although it is controlled so as to obtain a premixed gas having an appropriate air ratio that burns well and stably burns, at the time of rated operation, the air pressure rises, so that the ejector effect disappears and the fuel concentration decreases. Therefore, it functions as a premix burner at the time of startup, but automatically misfires when shifting to rated operation, and a thin premixed gas is ejected. Premixed burners may also reduce fuel concentration by adjusting the injected fuel and forcibly misfire.
Further, as shown in FIG. 3 (D), the throat 18 and the swivel
The premixing burner / mixer 20 may be configured on the upstream side of the tube 4 by the fuel injection nozzle 10 having the igniter 17 and the igniter 17. In the downstream side of the tube 4 is a pre-combustion chamber
When the gas turbine is started, the premixed gas is burned in the pre-combustion chamber 21 at the time of starting the gas turbine, and the air ratio is increased by the supply pressure of the combustion air which increases with the increase of the gas turbine load. It is provided to misfire and to supply a thin premixture to the combustion chamber 2 downstream of the segment. Further, as shown in FIG. 3 (E), a swirler 16 is provided at the outlet of the embodiment of FIG. 3 (D), and the premixed gas is swirled and supplied into the combustion chamber 2 so that the catalyst mixture 3 The diffusion mixing property of the injected combustion gas may be increased.

The catalyst segment 3 is filled with the catalyst 5 and has a premixer 6 upstream thereof. For example,
As shown in FIG. 2 (A), the catalyst segment 3 has an opening of an outlet of a fuel injection nozzle 9 at a minimum diameter portion of the Venturi tube 22 and a premixer 6 for sucking and premixing fuel with combustion air. 3 and the outlet is filled with a catalyst 5. In addition, as shown in FIG.
By forming a swirler 23 at the outlet side of the catalyst 5 itself, or by providing a swirler 24 independently downstream of the catalyst 5 separately from the catalyst 5 as shown in FIG. May be swirled. Further, as shown in FIG. 2 (D), a diffusion burner having a premixer 6 upstream of the catalyst 5 and an igniter 32 upstream of the premixer 6
25, a pre-combustion chamber is provided between the premixer 6 and the diffusion burner 25.
May form 26. In this case, the primary air A and the secondary air holes 27 in the radial direction are
Supplies secondary air A, and mixes fuel F and air A for combustion. Further, as shown in FIG. 2 (E), a premixer 28 may be provided around the diffusion burner 25 so as to be oblique to the injection axis of the diffusion burner 25. Also, as shown in FIGS. 2 (F) and 2 (G), the diffusion burner 25 of FIGS. 2 (D) and 2 (E) is connected to the throat 30, the swirler 31, and the fuel injection nozzle 9 having the igniter 32. May be replaced with a premixing burner / premixer 29. Further, as shown in FIG. 2 (H), a swirler 33 may be provided between the catalyst 5 and the pre-mixer 6 to improve the mixing property. Further, the premixer may have a structure other than the Venturi tube, and may use, for example, an ejector.

As a constituent material of the premixer segment 4 and the catalyst segment 3, it is preferable to use a heat-resistant material such as a heat-resistant alloy or ceramics, and most preferably to use ceramics. For example, each of the segments 3 and 4 is formed in a tube shape by entirely using ceramics or by lining the ceramics with a heat-resistant alloy or the like. Here, as the ceramic, it is preferable to use, for example, silicon carbide ceramics, silicon nitride ceramics, Sialon, or the like.

Further, as the catalyst 5, an integrated catalyst having a large number of through holes can be used, and a catalyst in which an active component is supported on the surface of a honeycomb, sponge or fiber integrated base material is preferable, and most preferable. Is the use of a honeycomb-type base material. Further, as a constituent material of the catalyst 5, it is preferable to use a base material such as a heat-resistant alloy or ceramics and an active component such as a noble metal or a base metal oxide. Here, Inconel, Hastelloy as the heat-resistant alloy, cordierite, silicon nitride as the ceramics, platinum and palladium as the noble metals, chromium oxide as the base metal oxide,
Use of cobalt oxide or the like is preferred. The size of the catalyst 5 is determined in consideration of thermal stress, reliability, and the like. However, it is preferable that the catalyst 5 has a small diameter, for example, a catalyst having a diameter of 15 cm or less.

As shown in FIG. 6, the catalyst 5 is fixed to the segment 3 using a snap ring 34 made of ceramics. The snap ring 34 is formed, for example, by forming a claw 35 for fixing the catalyst 5 on one side end of the C-shaped ring, and is formed to have a small thickness so as to obtain elasticity such that deformation at the time of attachment and detachment is possible. Insert this snap ring 34 into the tube 3
The catalyst 5 is fixed by being fitted into the annular grooves 36 before and after the catalyst 5 inside. Further, it is also possible to form a thick part to some extent in the snap ring 34 and to provide the catalyst 5 at the thick part. The segments 3 and 4 can be freely arranged so that stable combustion can be obtained. For example, as illustrated in FIG. 4, the catalyst segment 3 is annularly arranged around the premixer segment 4 (see FIG. 4A), or the premixer segment 4 is annularly arranged around one catalyst segment 3. [Figure (B)], or a plurality of sets of premixer segments 4 each including a plurality of catalyst segments 3 [Figure (C)], and premixing in the center. It is possible to arrange the reactor segment 4 around which the catalyst segment 3 is circumferentially arranged and further surround the outside thereof with the premixer segment 4 [FIG. Further, the cross-sectional shape of each of the segments 3 and 4 may be either circular or non-circular as shown in FIG.
It is also possible to arrange them three-dimensionally. For example, as shown in FIG. 5 (A), the premixer segment 4 is arranged on a different plane so as to open downstream on the catalyst segment 3, or as shown in FIG. 5 (B). It is also possible to arrange the premixer segment 4 crossing the injection axis of the catalyst segment 3.

According to the gas turbine combustor of the present invention configured as described above, LNG, LPG, low-calorie gas and other gas fuels such as coal gasification gas and diesel fuel, liquid fuel such as methanol, the catalyst heat-resistant temperature or less, Adiabatic flame temperature 800 ℃ ~ 1
The remaining fuel is injected into the premixer segment 4 to generate a premixed gas, which is injected into the catalyst segment 3 by an amount corresponding to 300 ° C. to generate catalytic combustion. And a premixed combustion using the high-temperature gas as an ignition source to obtain a combustion gas having a combustor outlet temperature of, for example, 1300 ° C. necessary for a gas turbine combustor.

(Effects of the Invention) As is apparent from the above description, the present invention provides a large-sized combustion apparatus in which the premixed gas from the premixer segment is burned by the combustion gas from the catalyst segment by the aggregate of the premixer segment and the catalyst segment. Since the combustor is configured, the size of the catalyst can be reduced regardless of the size of the combustor, and the stress and thermal stress generated in the catalyst can be reduced, and the reliability of the structure of the catalyst can be ensured. Further, since the catalyst temperature can be kept low, the life of the catalyst can be extended, the frequency of catalyst replacement can be reduced, and maintenance costs can be reduced. In particular, when the segment tube is made of ceramics, the replacement frequency can be reduced because the life of the segment is extended. Furthermore, by adjusting the concentration of the premixed gas injected from the premixer segment, the combustor outlet temperature can be raised to an arbitrary temperature equal to or higher than the catalyst heat-resistant temperature, so that the power generation efficiency of the gas turbine can be improved.

On the other hand, the segmentation makes it easy to replace parts, and the increase and decrease of the segments makes it easy to cope with gas turbines of various sizes.

Furthermore, NOx generation can be suppressed to a very small amount by catalytic combustion and stable premixed combustion using the combustion gas as a kind of fire, so that a catalyst device for power generation equipment can be unnecessary or simplified,
NOx countermeasure costs can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a principle view of the present invention, FIGS. 2 (A) to 2 (H) are central longitudinal sectional views each showing an embodiment of a catalyst segment, and FIGS. 3 (A) to 3 (E) are each a premixer segment. 4 (A) to 4 (E) are front views each showing an example of the arrangement of segments, and FIGS. 5 (A) and 5 (B) show the arrangement of the segments three-dimensionally. FIG. 6 (A) is a central longitudinal sectional view showing an example of a structure for attaching a catalyst to a segment tube. FIG. 6 (B) is a central longitudinal sectional view showing an example of a structure for attaching a catalyst to a segment tube. It is a perspective view showing an example. FIG. 7 is a schematic structural view showing an example of a conventional combustor for a catalytic combustion type gas turbine. DESCRIPTION OF SYMBOLS 1 ... Burner part, 2 ... Combustion chamber, 3 ... Catalyst segment, 4 ... Premixer segment, 5 ... Catalyst, 6 ... Premixer, 7 ... Premixer, 20 ... Premix Burner, 17,32
... igniter, 25 ... diffusion burner, 29 ... premix burner / premixer, 34 ... snap ring, 36 ... groove.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-108332 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23R 3/40

Claims (6)

(57) [Claims] 1. A premixer segment containing a premixer and a catalyst segment filled with a catalyst and containing a premixer upstream of the premixer segment are arranged in parallel and assembled. A combustor for a catalytic combustion type gas turbine, wherein a large-sized combustor for burning a premixed gas from a mixer segment with a combustion gas from the catalyst segment is formed. 2. A combustor for a catalytic combustion type gas turbine according to claim 1, wherein said premixer segment or said catalyst segment is made of ceramics. 3. The catalyst segment upstream of a premixer,
3. A combustor for a catalytic combustion type gas turbine according to claim 1, further comprising a preheating burner having an igniter. 4. The premixer of the premixer segment has an igniter, and has a function as a premix burner from the start of the gas turbine to a partial load. Item 4. A combustor for a catalytic combustion type gas turbine according to any one of Items 3 to 4. 5. An igniter is provided inside the premixer segment, and the premixed gas is burned inside the segment between the time of starting the gas turbine and the time of partial load, and is caused to misfire with the increase of the gas turbine load. 4. The combustor for a catalytic combustion type gas turbine according to claim 1, wherein the combustor has a function of supplying a premixed gas downstream of the segment. 6. The catalyst according to claim 1, wherein a circumferential annular groove is provided on an inner peripheral surface of the ceramic tube before and after the catalyst, and a ceramic snap ring is fitted into the groove. A combustor for a catalytic combustion type gas turbine according to any one of claims 2 to 5.