JPH02259331A - Combustion device for catalytic combustion type gas turbine - Google Patents

Abstract

PURPOSE:To provide a high reliability and further low NOx by a method wherein a pre-mixing segment having a premixing device therein and a catalyst segment having catalyst filled therein and storing the premixing device at an upstream side thereof are arranged in parallel and assembled to each other and a large-sized combustion device is formed. CONSTITUTION:A pre-mixing segment 4 having a premixing device 7 therein and a catalyst segment 3 having a small-sized catalyst 5 filled therein and storing a premixing device 6 at an upstream side thereof are arranged in parallel to each other and a large sized burner 1 is constituted by an assembly of these devices. Gas fuel of low calorie such as LNG and LPG and liquid fuel such as Diesel oil or the like are fed into the catalyst segment 3 by an amount corresponding to a temperature lower than a catalyst temperature, i.e. an adiabatic flame temperature of about 800 to 1,300 deg.C so as to perform a catalytic combustion. In turn, the remaining fuel is fed into the premixing segment 4 to generate the premixed gas and then the premixed gas is injected around a hot temperature gas injected from the catalyst segment 3. Then, the hot temperature gas serves as a pilot flame, so that fuel is premixed and ignited to get a combustion gas having an outlet temperature of the combustion device, 1,300 deg.C, for example.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a gas turbine combustor.More specifically, the present invention relates to a gas turbine combustor using OF of catalytic combustion and premix combustion.

(Prior Art) In a combustor for a gas turbine, it is desired to increase the combustion gas temperature at the combustor outlet while reducing NOx in consideration of thermal efficiency and environmental pollution in the power generation system. On the other hand, catalytic combustion has been proposed as one of the promising methods for low NOx combustion, but due to the relationship with the allowable temperature limit of the catalyst, it is possible to generate combustion gas at a high temperature, for example, around 1300°C, while maintaining low NOx properties. Therefore, it has been considered to combine catalytic combustion and gas-phase combustion to maintain the catalyst temperature below the catalyst's heat-resistant temperature to prevent catalyst deterioration while increasing the temperature of the combustion gas at the combustor outlet. There is.

As such a combustor, Japanese Patent Laid-Open No. 175925/1983 proposes a method 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. As shown in FIG. 7, in this combustion method, fuel injected from a nozzle 103 is pre-combusted to generate combustion gas that has been preheated to the temperature required for catalytic combustion, which is then catalytically combusted by a catalyst 101. Auxiliary fuel is injected into the outlet portion of the catalyst 101 through a pipe 102 penetrating inside the catalyst 101 to increase the fuel concentration, diffuse combustion of the flame-retardant fuel, and increase the temperature of the combustion gas.

(Problems to be Solved by the Invention) However, since the entire inside of the combustion chamber is covered with a single catalyst 101, a large catalyst is required when manufacturing a large combustor. However, large-sized catalysts are difficult to manufacture and have the disadvantage that their reliability is significantly impaired by thermal stress, etc., and it is currently considered difficult to put them into practical use industrially. Moreover, it is economically quite expensive.

Furthermore, since the combustor shown in Figure 7 performs diffusion combustion downstream of the catalyst outlet, it is not possible to suppress the influence of increased NOx due to this diffusion combustion, and the gas temperature at the combustor outlet can be reduced while keeping the catalyst combustion temperature low. If you try to increase it, there is a problem that the NOx reduction effect becomes lower.

An object of the present invention is to provide a large-scale combustor for a gas turbine that is highly reliable and low in NOx by using a small-sized catalyst that has already been put into practical use industrially.

(Means for Solving the Problems) In order to achieve the above object, the combustor for a catalytic combustion gas turbine of the present invention includes a premixer segment containing a premixer, a premixer segment filled with a catalyst, and a premixer segment on the upstream side thereof. Catalyst segments with built-in premixers are arranged in parallel and assembled to form a large combustor.

(Function) Therefore, while catalytic combustion is performed while maintaining the catalyst temperature, catalyst inlet flow rate, etc. at R week conditions, a thinner premixture than normal premixture is created around or inside the high temperature combustion gas injected from the catalyst. The combustion engine uses high-temperature gas as a spark to stably burn the premixed air, which is unstable in combustion, and suppresses the generation of NOx through the effects of catalytic combustion and lean premixed combustion. Further, by adjusting the concentration of the premixture injected from the premixer segment, the combustor outlet temperature of the combustion gas can be raised to a high temperature higher than the catalyst heat resistance temperature. Additionally, the catalyst is determined by the number and size of the catalyst segments, regardless of the size of the combustor, and can be downsized to an optimal size.

Furthermore, since the burner is constituted by an assembly of segments, the catalyst and other parts can be replaced by replacing the segments, and gas turbines of various sizes can be constructed by increasing or decreasing the number of segments.

(Example) Hereinafter, the configuration of the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows a schematic structure of a combustor for a catalytic combustion type gas turbine according to the present invention in a central vertical cross-sectional view. , a catalyst segment 3 filled with a small catalyst 5 and having a built-in premixer 6 on its upstream side is arranged in parallel,
A large burner 1 is configured by the aggregate.

The combustor usually has a 2100M4 structure consisting of a casing 11 and a liner 12, and an air flow path 13 is formed between the liner 12 and gauging 11 to allow compressed air A supplied from the gas turbine side. A premixer segment 4, a catalyst segment 3, and a liner cooling air hole 14 are provided to inject air into the combustion chamber 2 inside the liner 12, respectively. Furthermore, when the liner 12 is provided with secondary air holes, air A is also injected from the secondary air holes.

The premixer segment 4 is provided with a premixer 7 therein,
At a predetermined air ratio during rated operation, for example, a premixture that is slightly richer than the premixture supplied to the catalyst segment 3 but thinner than the premixture concentration in a normal premix combustor is supplied into the combustion chamber. ing. The premixer 7 is formed into an oval shape by a venturi tube 15 and a fuel injection nozzle 10, as shown in FIG. It is provided to obtain a premixture of .

Further, as shown in FIG. 3(B), the premixer segment 4 is provided with a swirler 16 at the outlet so as to swirl and inject the premixture into the combustion chamber 2, and the catalyst segment 4 is provided in the combustion chamber 2. It is also possible to improve the diffusive mixing property with the combustion gas injected from No. 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 fuel F injected from the fuel injection nozzle 10 is controlled by a regulating valve (not shown) or the like, and combustion air A is sucked in by the ejector effect during startup when the air pressure is low and at partial loads, for example, up to 20% load. However, during rated operation, the ejector effect disappears and the fuel concentration decreases because the air pressure increases during rated operation. Therefore, at startup, it functions as a premix burner, but when it shifts to rated operation, it automatically misfires and ejects a thin premix burner. Premix burners may also lower the fuel concentration by adjusting the injected fuel, forcing a misfire. Furthermore, as shown in FIG. 3(D),
A premix burner/mixer 20 may be configured on the upstream side of the tube 4 by the throat 18, the swirler 19, and the fuel injection nozzle 10 having the igniter 17. A combustion chamber 21 is formed, and a premixture is combusted in the precombustion chamber 21 when the gas turbine is started.
It is provided to increase the air ratio by the supply pressure of combustion air which increases as the gas turbine load increases, automatically or forcibly misfires, and supplies a thin premixture to the combustion chamber 2 downstream of the segment. There is. Furthermore, Figure 3 (E
), a swirler 16 is provided at the outlet of the embodiment shown in FIG. It is also possible to improve the diffusive mixing properties of .

Further, the catalyst segment 3 is filled with a catalyst 5 and is provided with a premixer 6 on the upstream side of the catalyst segment. The outlet of the fuel injection nozzle 9 is opened at the smallest diameter part, a premixer 6 for suctioning and premixing fuel with combustion air is formed oval on the upstream side of the tube 3, and the outlet is filled with a catalyst 5. Further, as shown in FIG. 2(B), the catalyst 5
The swirler 23 may be formed on the outlet side of the catalyst 5 itself, or the catalyst 5 may be formed separately from the catalyst 5 as shown in FIG. 2(C).
By independently providing a swirler 24 downstream of the second swirler 24, the combustion gas may be swirled and injected.
As shown in Figure (D), a premixer 6 is installed upstream of the catalyst 5.
Furthermore, a diffusion burner 25 having an igniter 32 may be provided upstream of the premixer 6, and a precombustion chamber 26 may be formed between the premixer 6 and the diffusion burner 25. In this case, primary air A is supplied to the pre-combustion chamber 26 in parallel with the fuel F, and secondary air A is supplied from the radial secondary air holes 27, so that the fuel F and air A are mixed and combusted. I have to. Also,
As shown in FIG. 2(E), a premixer 28 may be installed around the diffusion burner 25 so as to be oblique to the injection axis of the diffusion burner 25, or as shown in FIG. 2(F). as well as(
As shown in FIG. 2G, the diffusion burner section 25 in FIGS. Furthermore, as shown in FIG. 2(H), a swirler 33 may be provided between the catalyst 5 and the premixer 6 to improve the mixing property. The mixer may have a structure other than a Venturi tube, for example, one using an ejector.

As the 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 ceramics9. For example, each segment 3.4 is made entirely of ceramics. It is formed into a tube shape by applying a ceramic lining to 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.

Moreover, as the catalyst 5, an integrated catalyst having a large number of through holes can be used, and a catalyst in which the active ingredient is supported on the surface of a honeycomb-shaped, sponge-shaped, or fiber-type integrated matrix is preferable, and most preferable. is the use of a honeycomb type base material.

Further, as the constituent materials of the catalyst 5, it is preferable to use a base material such as a heat-resistant alloy or ceramics and an active ingredient such as a noble metal or a base metal oxide.Here, the heat-resistant alloy is Inconel or Hastelloy, and the ceramic is Cordierite. , silicon nitride, platinum as a noble metal,
As palladium and base metal oxides, it is preferable to use chromium oxide, cobalt oxide, etc. The size of this catalyst 5 is determined by considering thermal stress, reliability, etc., but it is preferable that it has a small diameter. For example, it is preferable to use a diameter of 15(2) or less.

As shown in FIG. 6, this catalyst 5 is fixed to the segment 3 using a snap ring 34 made of ceramics. The snap ring 34 is formed by forming a claw 35 for fixing the catalyst 5 on, for example, -rm@ of a C-shaped snap ring, and is formed to have a thin wall thickness so as to have sufficient elasticity to allow deformation during attachment and detachment. This snap ring 34 is fitted into the annular sleeves 36 at the front and rear of the catalyst 5 in the tube 3 to fix the catalyst 5. Further, it is also possible to form some thick portions in some places of the snap ring 34 and to lock the catalyst 5 with the thick portions.

Moreover, each segment 3.4 can be freely arranged so as to obtain stable combustion.

For example, as illustrated in FIG.
The catalyst segments 3 are arranged in an annular manner around [(A)
[Figure], the premixer segments 4 may be arranged in an annular manner around one catalyst segment 3 [Figure (B)], or a plurality of sets of premixers may be arranged between a plurality of catalyst segments 3. The premixer segment 4 is arranged in the center, and the catalyst segments 3 are arranged circumferentially around it, and the premixer segment 4 is arranged on the outside thereof. It is possible to surround it [Figure (D)].

Further, the cross-sectional shape of each segment 3.4 may be either circular or non-circular as shown in FIG.
), the premixer segment 4 may be arranged on a different plane from the catalyst segment 3 so as to open downstream, or as shown in FIG.
It is also possible to arrange the premixer segment 4 transversely to the injection axis of the premixer segment 4 .

According to the gas turbine combustor of the present invention configured as described above, low calorie gas such as LNG, LPG, coal gasified gas, other gas fuels, and liquid fuels such as diesel oil and methanol are heated to temperatures below the catalyst heat resistance temperature, that is, Adiabatic flame temperature 80
An amount equivalent to 0°C to 1300°C is injected into the catalyst segment 3 for catalytic combustion, while the remaining fuel is injected into the premixer segment 4 to generate a premixture, which is injected from the catalyst segment t-3. The combustor outlet temperature required for a gas turbine combustor, for example, 13
00"C combustion gas is obtained.

(Effects of the Invention) As is clear from the above explanation, the present invention configures a large combustor by an assembly of premixer segments and catalyst segments, so regardless of the size of the combustor, The catalyst can be made smaller, the stress and thermal stress generated within the catalyst can be reduced, and the reliability of the catalyst as a horizontal body can be ensured.

Furthermore, 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 life of the segment is extended and the frequency of replacement can be reduced. Furthermore, by adjusting the concentration of the premixture injected from the premixer segment, the combustor outlet temperature can be raised to any temperature above the catalyst heat resistance temperature, thereby improving the power generation efficiency of the gas turbine.

On the other hand, segmentation makes it easy to replace parts, and by increasing or decreasing the number of segments, gas turbines of various sizes can be easily accommodated.

Furthermore, the production of NOx can be suppressed to a very small amount through catalytic combustion and stable premixed combustion using the combustion gas as the spark, making it possible to eliminate or simplify the need for a catalytic device in power generation equipment.
NOx countermeasure costs can be significantly reduced.

[Brief explanation of drawings]

Figure 1 is a diagram of the principle of the present invention, Figures 2 (^) to (H) are central vertical sectional views showing examples of catalyst segments, and Figure 3 (
^) to ([) are central vertical cross-sectional views showing examples of premixer segments, Figures 4 (^) to (E) are front views showing examples of segment arrangement, and Figures 5 (A> and (B) is a central vertical cross-sectional view showing a schematic structure of the burner portion of an embodiment in which the segments are arranged three-dimensionally, and FIG. 6 (A) is a central vertical cross-sectional view showing an example of the structure in which the catalyst is attached to the segment tube. The top view and FIG. 6 CB) are perspective views showing an example of a snap ring. FIG. 7 is a schematic structural diagram showing an example of a conventional catalytic combustion gas turbine combustor. ■... Burner section, 2... Combustion chamber, 3... Catalyst segment, 4... Premixer segment, 5... Catalyst, 6... Premixer, 7... Premixing vessel, 20... premix burner, 17.32... igniter,
25... Diffusion burner, 29... Premix burner/premixer, 34... Snap ring, 36... Groove. Patent applicant: Central Research Institute of Electric Power Industry, Nishiden
Power Co., Ltd.

Claims (6)

[Claims] (1) A premixer segment with a built-in premixer and a catalyst segment filled with a catalyst and with a built-in premixer on the upstream side are arranged in parallel and assembled, and the assembly enables a large combustor. A combustor for a catalytic combustion gas turbine, characterized in that: (2) The combustor for a catalytic combustion gas turbine according to claim 1, wherein the tube is made of ceramic. (3) A preheating burner having an igniter is provided upstream of the premixer of the catalyst segment.
The combustor for a catalytic combustion gas turbine described above. (4) The premixer of the premixer segment has an igniter and functions as a premix burner from the start of the gas turbine until partial load.
The combustor for a catalytic combustion gas turbine described above. (5) providing an igniter inside the premixer segment;
It is characterized by having a function of combusting the premixture inside the segment from the time of starting the gas turbine to the time of partial load, causing a misfire as the gas turbine load increases, and supplying the premixture downstream of the segment. The combustor for a catalytic combustion gas turbine according to claim 1. (6) The catalyst is fixed by providing a circumferential annular groove in the inner peripheral surface of the ceramic tubes before and after the catalyst, and fitting a ceramic snap ring into the groove. The combustor for a catalytic combustion gas turbine described above.