JPS5924122A - Combustor for gas turbine - Google Patents

Abstract

PURPOSE:To improve ignition property and reduce pressure loss by a method wherein a catalyst bearing part is constituted by three-stage structure consisting of first stage, a ceramic honeycomb structure bearing a precious meral series catalyst, second structure, a refractory honeycomb structure bearing the same catalyst and third structure, a honeycomb structure catalyst body of composite oxide. CONSTITUTION:The ceramic, constituting the first stage of ceramic honeycomb structure, is alpha-alumina, zirconia or the like while the refractory alloy, constituting the second stage of the refractory alloy honeycomb structure, is the alloy of hastelloy, inconel or the like. The precious metal series catalyst, born by the structures of the first and second stages, begins combustion reaction from a comparatively low temperature. The composite oxide honeycomb structural catalyst body, constituting the third stage, has the effect of the catalyst by itself at a high temperature and is made of titanic acid, zirconate or the like of Ba, Mn, Ni, Co, Cu, Fe, Ca or the like added with alumina of high purity or the like, and it is prepared by mixing and forming into the honeycomb shape, thereafter, calcining under a pressure.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a gas turbine combustor used in a gas turbine power generation system, and more specifically, the present invention relates to a gas turbine combustor used in a gas turbine power generation system, and more specifically, it has excellent ignition characteristics at startup and a small pressure loss. The present invention also relates to a gas turbine combustor of a catalytic combustion type having a long life.

[Technical background of the invention and its problems]

In recent years, with the depletion of petroleum resources and the like, various alternative energies have been sought, and on the other hand, efficient use of energy resources has been required. Examples of systems that can meet these demands include a gas turbine/steam turbine combined cycle power generation system that uses natural gas as fuel, or a coal gasification gas turbine/steam turbine combined cycle power generation system, which are currently being considered. .

These gas turbine/steam turbine combined cycle power generation systems have higher power generation efficiency than conventional steam turbine power generation systems that use fossil fuels, so natural gas production is expected to increase in the future. It is expected to be a power generation system that can effectively convert fuels such as coal and gasified gas into electricity.

Soils used in gas turbine power generation systems
BACKGROUND ART A turbine combustor conventionally performs homogeneous combustion by igniting a mixture of fuel and air using a fuel plug or the like. An example of such a combustor is shown in FIG. In the combustor shown in FIG. 1, fuel injected from a fuel nozzle 1 is mixed with combustion air 3, ignited by a spark plug 2, and combusted. The roasted wheat gas is cooled and diluted to a predetermined turbine inlet temperature by adding cooling air 4 and dilution air 5, and then injected into the gas turbine from a turbine nozzle 6.

One of the important points in such a conventional combustor is that a large amount of NOx gas is produced during fuel combustion.

Above 1. The reason why NOx is generated is due to the presence of a high temperature area during combustion of fuel. NO
Normally, when no nitrogen component is present in the fuel, x is generated by the reaction between nitrogen and oxygen in the combustion air according to the formula shown below.

N2 +02 d 2NO The above reaction shifts to the right as the temperature increases, and the amount of nitrogen monoxide (NO) produced increases. Some of the NO is further oxidized to produce nitrogen dioxide (NO2).

FIG. 2 shows the temperature distribution in the fluid flow direction in a conventional gas turbine combustor. As shown in the figure,
The temperature distribution within the combustor has a maximum value, and after reaching the maximum temperature, it is cooled down to a predetermined turbine inlet temperature by cooling and dilution air. The maximum temperature inside the combustor is 200
Since the temperature can reach as high as 0°C, the production of NOx rapidly increases in this vicinity. As described above, the conventional gas turbine combustor has a problem in that a large amount of NOx is produced due to the presence of a partially high-temperature section. Therefore, a flue gas denitrification device or the like must be provided, which poses problems such as the device becoming complicated.

In order to solve these problems with gas turbine combustors, various combustion systems have been studied.

As one of these, recently, a heterogeneous combustion method (hereinafter referred to as
catalytic combustion method) has been proposed. The catalytic combustion method uses a catalyst to combust a mixture of fuel and air. According to this method, combustion can be started at a relatively low temperature, no cooling air is required, and the amount of combustion air is increased, resulting in a lower maximum temperature.
Therefore, it is possible to extremely reduce the generated N0x(u).

Furthermore, the turbine inlet temperature remains the same as in the conventional case, and the fuel can be pre-combusted. Figure 3 is a conceptual diagram of such a catalytic combustion type fuel;
11 (Part 7 is filled with a catalyst body at the end of the honeycomb groove. In addition, if it is the same device or material as in Fig. 1, the same reference numeral is used. +1 in Fig. 4, Among the above-mentioned gas turbine combustion devices, A: conventional combustion method; B;
Two-stage combustion power type, C: shows the temperature distribution within each combustor in the catalytic combustion type. In the catalytic combustion method, the maximum temperature is lower than in other methods, and it can be seen that a heterogeneous combustion reaction gradually starts from a low temperature, and combustion progresses with a homogeneous combustion reaction halfway through. .

Catalysts that are being considered for use in such catalytic combustion type combustors include those in which a 1λ gold-based catalyst is supported on a ceramic or metal carrier. The fully utilized combustor has not yet been pared down.

Here, a combustor filled with a ceramic carrier carrying a noble metal catalyst and a combustor filled with a thermal alloy carrier carrying a noble metal catalyst are shown.

The functions of each are examined as follows.

First, the ignition characteristics of the catalyst light at the time of starting the turbine, ie, the characteristics at the start of the heterogeneous oxidation reaction, will be discussed. Figure 1B5 is a diagram showing the temporal change in surface temperature at the inlet portion of the catalyst-packed portion, in which a ceramic carrier is used, and a heat-resistant alloy carrier is used in b, respectively. When the temperature of the mixed gas of fuel and air supplied to the catalyst filling section (1) is increased, when the temperature is low, there is almost no combustion reaction for both.Since there is no anchor, the surface temperature is t
The temperature is proportional to the gas temperature, but when the temperature exceeds that temperature, both start a co-combustion reaction and generate heat. When using a heat-resistant alloy carrier (b), when using a ceramic carrier (a)
Compared to this, because the carrier has good thermal conductivity, the reaction heat easily moves to the downstream side of the catalyst-packed part, and the surface temperature of the inlet part does not rise easily. Therefore, when a heat-reducing alloy carrier is used, the preheating temperature of the mixed gas required for ignition (heterogeneous oxidation reaction) is higher than when a ceramic carrier is used, and the ignition characteristics are inferior.

Next, considering the case where a steady state is reached, the heat conductivity of the heat-resistant alloy carrier is better than that of the ceramic carrier, so the combustion heat on the downstream side of the catalyst filling part is reduced. is easily conducted to the inlet portion, and the temperature at the inlet portion of the catalyst filling portion becomes high. Therefore, in a steady state, when a heat-resistant alloy carrier is used, the preheating temperature of the mixed gas is lower and the temperature is better. Also, considering the pressure loss in this case, the ceramic carrier has a thicker recessed wall of the catalyst having a single comb structure, so the opening ratio is smaller, and therefore the pressure loss is larger.

Considering the characteristics of each carrier described above, the present inventors first filled a honeycomb structure ceramic carrier on which a noble metal catalyst was supported in the first stage, and a honeycomb structure heat-resistant alloy in which a noble metal catalyst was supported in the second stage. A gas turbine combustor filled with a carrier was proposed.

However, near the outlet of the catalyst filling section, the temperature is 100
If a heat-resistant alloy carrier is used, the concave walls of the honeycomb structure catalyst will gradually become thinner due to scaling, and there is a possibility of breakage, which is a problem in terms of durability. It has points.

[Purpose of the invention]

It is an object of the present invention to provide a gas turbine combustor which solves the above-mentioned problems, has excellent ignition characteristics at startup, has low pressure loss, and has a long life.

[Summary of the invention]

As a result of extensive studies, the present inventors discovered that the above object could be achieved by using a composite oxide formed into a honeycomb structure near the outlet of the catalyst filling section, and completed the present invention. I came to the conclusion.

That is, in the gas turbine combustor of the present invention, in the catalytic combustion type gas turbine combustor in which a mixture of fuel and air is combusted using a catalyst, the catalyst filling section is made of ceramics supporting a noble metal catalyst in the first stage. The first layer of the honeycomb was made of dead bodies, and the second layer was loaded with Nippon Metals p111B medium.
Three-stage 41η filled with a honeycomb structure made of a thermal alloy and a honeycomb S catalyst made of a composite oxide in the third stage.
It is characterized by being made of artificial material.

In the following, the invention will be explained in more detail.

Any ceramic can be used as long as it has good heat resistance and mechanical strength as the ceramic constituting the first stage ceramic honeycomb structure used in the present invention. Such ceramics include, for example, α-
Examples include alumina, zirconia spinel, mullite, cordierite, and titania.

In the present invention, there is no particular restriction on the side heating alloy constituting the second-stage heat-resistant alloy structure, as long as it has good heat resistance; for example, alloys such as Hastelloy and Inconel are used. used.

The noble metal catalyst supported on the first and second stage honeycomb structures may be any catalyst as long as it is capable of starting a combustion reaction at a relatively low temperature. Examples of such noble metal catalysts include platinum (Pt), radium (Pd), rhodium (R), and ruthenium (Ru).
) and iridium (Ir), and one or more selected from the group consisting of these may be used. Specifically, for example, Pt, Pd5Pt, -P
d, PL-N10. Pt-AP, Pt-Coos,
Pd-Ni0, Pt-Pd-NiO, etc. are praised.

The noble metal catalyst may be supported on the honeycomb structure by a conventional method.

In the present invention, the honeycomb-structured catalyst body made of a composite oxide constituting the third stage of the catalyst filling section is such that the composite oxide itself has a large effect as a catalyst at high temperatures, and is heat resistant. Unlike alloys, there is no need to worry about scaling. Examples of such composite oxides include barium titanate (BaTiQg), manganese titanate (MnTiOs), and nickel titanate (NiTiOs).
), cobalt titanate (COTD3), titanate@
(CuTiOs), iron titanate (FeTiOa), calcium titanate (CaTi03), magnesium titanate (MgTiOs), cobalt zirconate (Co
ZrOs), nickel zirconate (NiZrO3)
Alternatively, calcium zirconate (CaZrO3) to which high-purity alumina is added may be mentioned, and one or more selected from the group consisting of these may be used.

In order to make the above-mentioned composite oxide into a honeycomb structured catalyst body,
For example, it can be easily prepared by kneading a composite oxide, forming it into a honeycomb shape using a conventional method, and then firing it under pressure. Alternatively, these composite oxides may be supported on a ceramic carrier as in the preparation of a normal honeycomb catalyst.

It constitutes the catalyst filling part of the gas turbine combustor of the present invention.

It is preferable that each honeycomb structure is filled with honeycomb structures from the first stage to the third stage in succession in order to improve thermal conductivity. However, in the present invention, there is no problem in the present invention even if a gap is provided between each honeycomb structure.

When a gap is provided, the combustion efficiency is improved because the mixed gas of fuel and air creates turbulent flow in the gap and diffuses.

〔Effect of the invention〕

The gas turbine combustor of the present invention eliminates the risk of scaling due to the use of a honeycomb structured catalyst body made of a composite oxide near the outlet where the highest temperature occurs in the first part of the catalyst. , has excellent durability. In addition, since this catalyst body itself has catalytic activity, there is no need to first support activated alumina on the support and then further support the noble metal catalyst, unlike a normal ceramic support on which a catalyst is supported. . Therefore, at high temperatures, unlike noble metal catalysts supported on ceramic carriers, problems such as a drop in catalytic activity due to peeling off of the activated alumina layer do not occur.

Furthermore, in the catalyst filling section, since a ceramic carrier is used in the first stage and a heat-resistant alloy phase is used in the second stage, the gas turbine combustor of the present invention has excellent ignition characteristics and low pressure. The loss is small.

The present invention will be explained in more detail below with reference to Examples.

[Embodiments of the invention]

Practical series 1 Honeycomb structure 5 (1"η) in which a precious metal catalyst is supported on a ceramic carrier with almost the same catalytic activity, and a honeycomb structure in which a metal J+Ci catalyst is supported on a heat-resistant alloy carrier, respectively. Platinum was used as the noble metal catalyst, and cordierite was used as the ceramic support in (5).
Inconel 601 was used as the heat-resistant alloy carrier in Q3). Furthermore, honeycomb +t made of composite oxide
Q-formed catalyst body (as Q, 10λ%J-,% of high purity alumina is added to barium titanate powder, kneaded and formed into a honeycomb structure, and then pressure-fired to form a honeycomb structure catalyst body. Each of the )-Nicum structures was prepared so that the unit cross-sectional area, υ, cell number was 31 cells/Gnt, and the outer diameter was 25 cells/Gnt.

Using the above honeycomb structure, place the above honeycomb structure (A) 15c1rL in a reaction tube with an internal diameter of 25nφ.

b 2 above honeycomb off + g corpse (B) 15 cx-,
And 3 (1
In the second stage, the honeycomb structure (B) was connected to the first stage, and in the third stage, the honeycomb structure catalyst (a 31-layer catalyst filled with 4 cTL of Q) was prepared.

Next, a mixed gas of air and methane at a constant concentration was passed through the catalyst-filled portion of each reaction tube while being heated at a constant rate, and the surface temperature of the inlet portion of the catalyst-filled portion at that time was measured. The results are shown in FIG.

As is clear from FIG. 6, it has been confirmed that C, which has the same configuration as the IL filling part of the gas turbine combustor according to the present invention, ignites at approximately the same temperature as A, which uses a ceramic holder. It was done. In addition, it was confirmed that in the steady state, C, which is one thread in the present invention, has a, l:, and j) at a high temperature.

Example 2 Using the same equipment as in Example 1, the mixing ratio of air and methane was adjusted so that the adiabatic flame temperature (calculated value of 11°) of the combustion gas at the outlet of the catalyst filling part was constant. The temperature of the mixed gas was raised at a constant rate while flowing through the catalyst filling section. At that time, the combustion gas temperature at the outlet of the catalyst filling section was measured for each of a to e. The results are shown in FIG.

As is clear from the 71st case, it was confirmed that C according to the present invention reached the steady state fastest.

Example 3 The three types of 7-two cam groove ends a to e used in Example 1 were heated in an electric furnace at 1300°C for 24 hours and then cooled for 2 hours, which was repeated five times.

These No. 2 cam structures were filled in the reaction tube used in Example 1, and a mixed gas of methane/air = 0.03 (1 mole) preheated to 500 °C was passed through it. The temperature of the combustion gas at the outlet of the catalyst filling section was measured. The above operation was repeated for each of the fourteenth honeycomb structures a"'-c, and the temperature of the combustion gas at the outlet of the catalyst light no. 1 was measured every 130 hours. It is shown in FIG.

As is clear from FIG. 8, it was confirmed that configuration C according to the present invention caused the least decrease in the combustion gas temperature at the outlet portion, and had excellent durability.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a normal gas turbine combustor, Fig. 2 is a diagram showing the temperature distribution of a normal gas turbine combustor, Fig. 3 is a conceptual diagram of a catalytic combustion type gas turbine combustor, and Fig. 4 are a normal gas turbine combustor 5, a two-stage combustion type gas turbine combustor B, and a catalytic combustion type gas turbine combustor,
Figure 5 is a diagram showing the temperature distribution of each of C., Figure 5 is a diagram showing the surface temperature of the inlet part of the catalyst filling part when the mixed gas of air and fuel is heated and flowing through the catalyst filling part, and Figure 6 is is a diagram showing the same relationship as FIG. 5 in Example 1, and FIG. 7 shows the combustion gas temperature at the outlet of the catalyst filling section when the mixed gas of air and fuel is heated and flows through the catalyst-packing section. The figure shown in FIG. 8 is a diagram showing a change in combustion gas temperature at the outlet portion of the catalyst filling part after the heating/cooling cycle is repeated for the honeycomb structure. 1...Fuel nozzle, 2...Spark plug, 3...
・Combustion air, 4... Cooling air, 5... Dilution air, 6... Turbine nozzle, 7... No. 4f
# Catalyst-forming body, a... A honeycomb structure made of a ceramic carrier supporting a ul metal catalyst, b... A honeycomb structure made of a heat-suppressing liquid carrier supporting a precious metal catalyst, C. ...A three-stage structure catalyst body according to the present invention. Fig. 3 Collection of 100 yen Fig. 5 Saitama (min) Fig. 6 7J1 (min)

Claims (1)

[Claims] In a catalytic combustion type gas turbine combustor that burns a mixture of fuel and air using a catalyst, the catalyst filling part is a ceramic structure with a noble metal catalyst supported on the first stage, and the second stage is a ceramic structure that supports a precious metal catalyst. It is characterized by having a three-stage structure, each filled with a heat-resistant alloy-made nicum structure on which a noble metal catalyst is supported, and a nicum-structured catalyst made of a composite moltenide in the third stage. Gas turbine combustor.