JPS63232852A - Catalyst for gas turbine burner and its production - Google Patents

Abstract

PURPOSE:To improve the ignition temp. and combustion efficiency after a long- time use by depositing a noble metal element, nickel, and magnesium in a specified atomic ratio on a heat-resistant carrier to form the title catalyst for a gas turbine burner. CONSTITUTION:An alumina slurry contg. the oxide or salt of a rare-earth element is coated on the surface of a heat-resistant carrier, dried, and baked preferably at 700-1,000 deg.C to form an alumina layer carrying the rare-earth element. The catalyst carrier is dipped in the mixed soln. of a noble metal element compd. and the compds. of the nickel and magnesium as the promoter metallic elements, and then baked at 700-1,000 deg.C to obtain the catalyst for a gas turbine burner. When the atomic ratios of the nickel and magnesium to the noble metal element to be deposited on the catalyst carrier are denoted by (x) and (y), 2<=(x+y)<=3 and 0.5<=y/x<=2 must be fulfilled.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a catalyst body used in a catalytic combustion type gas turbine combustor, and more specifically, it relates to a catalyst body that has excellent low-temperature ignitability and high-temperature durability. The present invention relates to a good catalyst body for a gas turbine combustor.

(Prior art) In recent years, it has become possible to burn mixed gases such as natural gas with high efficiency, and at the same time, it has become possible to burn nitrogen oxides (NO
A catalytic combustion method has been proposed as a combustion method that produces a small amount of
105536) This catalytic combustion method burns the mixed gas using the catalytic action of a noble metal element such as palladium or platinum. As is well known, the catalytic reaction caused by the catalytic action of the noble metal element can proceed efficiently at a low temperature of about 300° C. if a sufficient active surface area is secured. Therefore, according to the catalytic reaction method, combustion can be started at a relatively low temperature, and the combustion temperature rises slowly without reaching a maximum value, and the maximum temperature is as low as about 1500°C. Therefore, especially when a gas containing nitrogen such as air is used as the gas containing oxidizing gas, the generation of NOx can be extremely reduced, and at the same time, thermal deterioration of the combustor itself can be prevented. can do.

Incidentally, the noble metal element serving as the catalyst is generally used by supporting it on a catalyst carrier. That is, a catalyst carrier is formed by forming an alumina carrier layer for increasing the effective surface area on the surface of a catalyst carrier body made of cordierite and having a honeycomb shape, for example, and the alumina carrier layer of this catalyst carrier is The catalyst is made by supporting fine particles of a noble metal element. Here, since the efficiency of the catalytic action increases as the surface area of the catalyst increases, the fine particles of the noble metal element are made as small as possible. Also,
A rare earth metal or the like is supported on the alumina carrier layer in order to prevent a reduction in surface area due to combustion heat.

Among such catalyst bodies, those manufactured for use in gas turbine combustors are catalyst bodies for gas turbine combustors.

However, when using such catalyst bodies for gas turbine combustors for long periods of time at high temperatures, combustion efficiency and
There was a problem that low-temperature ignitability etc. easily deteriorated. This will be explained with reference to the graph of the change in combustion temperature over time shown in FIG.

After being heated by an appropriate heating means, the mixed gas led to the catalyst body is ignited at a predetermined ignition temperature (for example, 300°C) as shown in curve a, and then reaches a steady combustion temperature (for example, 1
It is desirable to maintain this steady combustion temperature for a long time, but in reality, as shown in the curve, the temperature rises to about 1500°C at one time. This resulted in a decrease in combustion efficiency. Although not shown, when the mixed gas is ignited again using the catalyst whose combustion temperature has been lowered as described above,
This time, it did not ignite at a low temperature of around 300°C, and there was also a deterioration in low-temperature ignitability. This tendency is reflected in the song lI in Figure 3.
As shown in C, when the particle size of the noble metal element that is the catalyst is made smaller in order to lower the initial ignition temperature, -[12] becomes extremely high.

The cause of these problems is that, for example, in a temperature range of 600'C or higher, the noble metal particles supported on the alumina carrier layer begin to aggregate, reducing the active surface area required to cause a catalytic reaction with the mixed gas, and reducing its activity. This is thought to be due to a decline in performance.

In order to solve this problem, the above-mentioned "catalyst body for gas turbine combustor in which nickel (N1) is further supported on the alumina carrier layer" (Japanese Patent Application Laid-Open No. 60-196511, Japanese Patent Application Laid-open No. 61-2) was developed.
8455) has been proposed.

However, even in the latter catalyst body for a gas turbine combustor, the high-temperature durability, that is, the ignition temperature and combustion efficiency after long-term use, were still insufficient, and further improvements were desired.

(Problems to be Solved by the Invention) As described above, although various improvements have been attempted in the conventional catalyst bodies for gas turbine combustors, there is still a problem that the high temperature durability is not sufficient. there were.

The purpose of this invention is to solve the above problems,
It is an object of the present invention to provide a catalyst body for a gas turbine combustor, which has significantly superior high-temperature durability compared to conventional catalyst bodies, and a method for manufacturing the same.

[Structure of the Invention] (Means and Effects for Solving the Problems) As a result of intensive research to achieve the above object, the present inventor has developed a catalyst comprising noble metal elements and rare earth elements supported on an alumina carrier layer. The present invention was completed based on the discovery that significant effects can be obtained by simultaneously supporting a predetermined amount of nickel (Ni>) and magnesium (Mg) as promoter metal elements on the medium.

That is, the catalyst body for a gas turbine combustor of the present invention is a catalyst body for a gas turbine combustor, in which at least a noble metal element and nickel/magnesium are supported on a catalyst carrier, and the supported amounts of nickel and magnesium are as follows:
When the respective atomic ratios x and y of the noble metal elements are 2≦(X+y)≦3 and 0.5≦y/x≦2.

The catalyst carrier preferably includes a heat-resistant carrier body and an alumina carrier layer formed on the carrier body to directly support the noble metal element and the like.

The heat-resistant carrier body is not particularly limited as long as it has stable properties in a high-temperature oxidizing atmosphere of about 1300°C, and examples thereof include cordierite, mullite, α-alumina, zirconia spinel, Ceramic carriers such as titania can be used. Further, the shape of this carrier is not particularly limited, but it is preferably honeycomb-shaped in order to reduce pressure loss under high wind speed.

In addition, the alumina carrier layer formed on this carrier body has
It is preferable that a rare earth element is supported in addition to the conventional noble metal element. These rare earth elements include lanthanum (La), praseodymium (Pr), neodymium<Nd
) etc. or mixtures thereof can be mentioned as preferred.

The supported amount of these rare earth elements is preferably set to be 5 to 20% by weight of the alumina carrier layer in terms of oxide.

In addition, examples of noble metal elements supported on the alumina carrier layer include platinum (Pt) and palladium (Pd), and the amount of these supported is set to be 20% by weight or more with respect to the alumina carrier layer. It is preferable to do so.

In the catalyst body of the present invention, the above two
In addition to the seed component elements, nickel (Ni) and magnesium (Mg) are supported as promoter metal elements. The amount of these supported is determined by the atomic ratio to the noble metal element as X −Ni, /Pd, V −M(]
/Pd, then 2≦(×+y)≦3 and 0
．． It is set as 5≦y/x≦2.

In the present invention, it has not been clearly elucidated what role nickel and magnesium play, but in general, nickel and magnesium particles are interposed between fine particles of a noble metal element, which is a catalyst element, and the noble metal element It is thought that this prevents the fine particles from agglomerating due to combustion heat.

Figures 1 and 2 summarize the experimental results of the examples of the present invention, which will be described later, in order to clarify the roles of nickel and magnesium, and show the results for gases with atomic ratios x and y, respectively. The ignition temperature and combustion efficiency of a catalyst body for a turbine combustor are shown.

Referring to FIG. 1, the horizontal axis of this graph represents the sum of the atomic ratios (x + y), and the vertical axis represents the ratio y/x of the atomic ratios. Further, the numbers in the circles represent the ignition temperature of the body after use for 100,100 hours when (X+V>, V/X have the respective values).

As is clear from the figure, in a gas turbine combustor catalyst body supporting arbitrary amounts of nickel and magnesium,
The ignition temperature will be around 400″C, but as mentioned above, 2≦
By setting (x + y)≦3 and 0.5≦y/x≦2, this can be reduced by about 50”C to 100℃3.
The temperature can be around 00°C to 350°C.

Also, referring to FIG. 2, the numbers in the circles drawn on the graph having the same vertical and horizontal axes as above represent the combustion efficiency of the catalyst body after 100 hours of use.

According to this, when the amount of nickel and magnesium supported is arbitrary, the combustion efficiency is 20 to 60%, but 2≦
By setting (x + y)≦3.0.5≦y/x≦2, it can be improved by about 30 to 70% to approximately 90 to 100%.

Therefore, according to the present invention, high-temperature durability can be significantly improved without impairing low-temperature ignitability, which is a characteristic of the catalytic combustion method. Furthermore, even if the supported amount of nickel or magnesium is within the range 2 < (x + y)
<3 and 0.5<y/x 2 If it deviates from 2, the synergistic effect obtained by making both coexist will be lost.

Next, the most suitable method for producing the catalyst body for a gas turbine combustor of the present invention is a co-impregnation method in which the noble metal element and nickel/magnesium are simultaneously supported on the catalyst carrier.

To explain this method specifically, an alumina slurry containing rare earth element oxides or salts is applied to the surface of a heat-resistant carrier body, and then dried and fired to form an alumina carrier layer that supports rare earth elements. Form. The appropriate firing temperature at this time is 700°C to 1000°C. Next, the catalyst carrier on which the alumina carrier layer has been formed is immersed in a mixed solution prepared by dissolving a noble metal element compound and a nickel-magnesium compound as a promoter metal element. At this time, it is preferable to use, for example, chlorides, nitrates, metal organic compounds, etc. as the above-mentioned elemental compounds. The immersion causes the noble metal element and nickel magnetrum to be simultaneously supported on the alumina carrier layer. Thereafter, the entire catalyst carrier is fired at 700 to 1000°C to obtain the catalyst body for a cast turbine combustor of the present invention.

When the noble metal element as a catalyst and nickel/magnesium as a co-catalyst are supported on the catalyst carrier at the same time,
It is believed that the noble metal elements and nickel/magnesium are uniformly supported on the alumina support. Therefore, it is expected that the fine particles of the noble metal element will be sufficiently separated from each other, and the high temperature durability will be further improved. In order to support this prediction, the data marked with asterisks in FIGS. 1 and 2 show the ignition temperature and combustion efficiency of a catalyst body for a gas turbine combustor manufactured by the alternate impregnation method for comparison. From this data, it can be seen that the performance of the catalyst body manufactured by the alternate impregnation method is about 20°C in loading/unloading temperature and around 10% in combustion efficiency compared to the catalyst body of the same composition manufactured by the co-impregnation method. Each is inferior. Therefore, according to the co-impregnation method of the present invention, it is possible to produce a catalyst body for a gas turbine combustor that has even better high-temperature durability.

Examples of the present invention will be shown below, but the invention is not limited thereto.

(Example) Example 1 (1) Production of gas turbine combustor catalyst body Add 24g of lanthanum nitrate to 125a of alumina sol (solid content: 80% by weight)
After mixing in a ball mill for 2 hours, the resulting mixture was mixed on a nisilitic honeycomb carrier (200 t/in2).
Alumina support layer supporting lanthanum was formed by applying the mixture to L, body +111), drying, and firing at 900° C. for 5 hours.

Next, the honeycomb-shaped carrier obtained above was immersed in an aqueous solution containing 27 g of palladium chloride, 17 o of nickel chloride, and 119 g of magnesium chloride, dried, and then calcined at 800° C. for 3 hours to form PD into the alumina carrier layer.
A catalyst body of the present invention was obtained by supporting Ni and Mg.

Further, this catalyst body was activated by heat treatment at 550° C. for 3 hours in a hydrogen atmosphere.

(2) Catalyst body evaluation test (gas turbine combustion test)
The catalyst body obtained above was installed in a simulating device for a catalytic combustion type gas turbine combustor, and its combustion characteristics were evaluated. The combustion conditions at this time were a gas flow rate of 30w/sea, a fuel concentration of methane of 3%, a catalyst amount of 3Qcc, and a combustion time of 10
The methane ignition temperature and combustion efficiency after 0 hours were measured and the results are shown in the table.

Examples 2 to 11 Comparative Examples 1 to 8 Catalyst bodies were produced in the same manner as in Example 1, except that the amount or type of promoter metal element supported on the alumina carrier layer was varied as shown in the table. After that, similar evaluation tests were conducted and the results are shown in the table.

Roughly as Example 12, a sample was produced in the same manner as in Example 1 above, except that the noble metal element and the promoter metal element were impregnated and supported from separate solutions, and then the same evaluation test was conducted and the results were evaluated. Shown in the table.

(Left below) 'NO12 is produced by alternate impregnation method and co-impregnation method [Advantage of the invention 1] As explained above, according to the present invention, it is possible to obtain The durability, that is, the ignition temperature and combustion efficiency after long-term use, can be significantly improved compared to conventional catalyst bodies.Furthermore, the catalyst body for gas turbine combustors of the present invention also prevents the generation of NOx, etc. Therefore, it is expected to be used in gas turbine combustors in various fields, and its industrial value is extremely large.

[Brief explanation of drawings]

1 and 2 are graphs showing the ignition temperature and combustion efficiency of gas turbine combustor catalyst bodies according to an embodiment of the present invention and a conventional example, respectively, after long-term use, and FIG. FIG. 2 is a graph diagram showing a change over time in combustion temperature in a gas turbine combustor using a conventional catalyst body for a gas turbine combustor.

Claims (5)

[Claims] (1) A catalyst body for a gas turbine combustor comprising at least a noble metal element and nickel/magnesium supported on a catalyst carrier, wherein the supported amounts of nickel and magnesium are determined by x and y, respectively, in their respective atomic ratios to the noble metal elements. When 2≦(x+y)≦3, and 0.5≦y/x≦
2. A catalyst body for a gas turbine combustor, characterized in that: (2) A patent claim characterized in that the catalyst carrier comprises a heat-resistant carrier body and an alumina carrier layer formed on the carrier body to directly support the noble metal element and nickel/magnesium. A catalyst body for a gas turbine combustor according to item 1. (3) The catalyst body for a gas turbine combustor according to claim 2, wherein the alumina carrier layer supports a rare earth element in addition to the noble metal element and nickel/magnesium. (4) The catalyst body for a gas turbine combustor according to claim 3, wherein the noble metal element is palladium. (5) At least a noble metal element and nickel/magnesium are supported on a catalyst carrier, and the amount of nickel and magnesium supported is 2≦(x+y)≦, where x and y are the respective atomic ratios to the noble metal element. 3 and 0.5≦y/x≦2, the method for manufacturing a catalyst body for a gas turbine combustor, wherein the noble metal element and nickel/magnesium are simultaneously supported on the catalyst carrier. A method for producing a catalyst body for a combustor.