JPS62218727A - Gas turbine combustor - Google Patents

Abstract

PURPOSE:To suppress an abnormal increase in temperature of a catalyst, enable a long life of the catalyst, reduce a pressure loss within a catalyst charging area and improve an efficiency of combustion by a method wherein a temperature of the catalyst charging area and a ratio in volume of fuel gas and air (F/A) are controlled to each other. CONSTITUTION:Fuel and air are injected from a fuel nozzle 11 and an air injection port into an area A indicated by a dotted line in compliance with a set condition of combustion gas within a gas turbine nozzle 6 so as to form first mixture of desired mixing ratio (F/A). A catalyst charging area B filled with a combustion catalyst 13 is arranged at a rear stage of the area A and a part of the first mixture is ignited with catalyst. The rear stage is provided with an area C for supplying a desired amount of fuel from a fuel nozzle 11a to the flowing-out gas containing unburnt material and igniting the mixture. The catalyst charging area B is provided with means 14 for sensing catalyst temperature and means 15 for adjusting air volume operating in cooperation with the sensing means 14. Since the catalyst temperature and F/A are controlled to each other, an abnormal high temperature of the catalyst can be suppressed.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention II relates to a gas turbine combustor used in a gas turbine power generation system, and more specifically, to a method for reducing nitrogen oxides (hereinafter referred to as NOx) during combustion. The amount generated is small,
The present invention also relates to a catalytic combustion type gas turbine combustor that has good combustion efficiency.

[Technical background of the invention and its problems] In recent years, with the depletion of petroleum resources and the like, various types of energy are required, but at the same time, efficient use of energy resources is also required. Examples of systems that meet these demands include gas turbine/steam turbine combined cycle power generation systems that use natural gas as fuel or coal gasification gas turbine/steam turbine combined cycle power generation systems, which are currently being studied.

These gas turbine/steam turbine combined cycle power generation systems are expected to increase their production in the future due to their high power generation (() compared to conventional steam turbine power generation systems that use fossil fuels. It is expected to be a power generation system that can effectively convert fuels such as natural gas and coal gasified gas into electricity.

BACKGROUND ART Conventionally, in a gas turbine combustor used in a gas turbine power generation system, a mixture of fuel and air is ignited using a spark plug or the like to perform homogeneous combustion. An example of such a combustor is shown in FIG. 5. In the combustor shown in FIG. 5, fuel injected from a fuel nozzle 1 is mixed with combustion air 3, ignited by a spark plug 2, and combusted. It is something. Cooling air 4 and dilution air 5 are added to the burned gas, that is, the combustion gas, and after cooling and diluting it to a predetermined turbine inlet temperature, it is injected into the gas turbine from the turbine nozzle 6. 8 is a swirler.

One of the serious problems with such conventional combustors is that a large amount of NO! is produced when the fuel is combusted. Gas is generated and causes environmental pollution.

”: The reason why the NOx described above is generated is that a high temperature section exists in the combustor during combustion of fuel. NO
X is 1. Normally, when there is no nitrogen component in the fuel, it is produced by reacting with nitrogen in the combustion air and oxygen (according to the formula shown below).

)12+02:! 2NO In the above reaction, the higher the temperature, the more the reaction shifts to the right side and the amount of nitrogen monofluoride (MO) produced increases. A portion of this NO is further oxidized to produce nitrogen dioxide (NO2).

FIG. 6 shows the temperature distribution in the fluid flow direction in the conventional gas turbine combustor illustrated in FIG.
As shown in the figure, the temperature distribution within the combustor has a maximum value, and after reaching the maximum temperature, the combustor is cooled to a predetermined turbine inlet temperature by cooling and external water air. Since the maximum temperature inside the combustor can reach as high as 2000° C., the amount of NOx produced rapidly increases around this temperature. 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 installed downstream of the combustor, which inevitably makes the device complicated.

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

If the generated Now 14 can be reduced, the flue gas denitrification device can be omitted or simplified, and the fifth-order combustion method can be cited as a combustion method aimed at such a reduction in NOx. That is, (1) A method of performing water jetting or water injection.

(2) Two-stage combustion method in which combustion air is introduced in two stages and combustion is carried out in two stages, and (3) +JI gas ref + recirculation method.However, these methods have the following problems. be. In other words, in method (2), the thermal efficiency of the combustor deteriorates because steam or water is injected, and in method (2),
Since air is introduced in two stages, the amount of air introduced must be carefully adjusted, and the maximum temperature inside the combustor is still not low enough, resulting in NOx 51
Furthermore, although method (3) can be used for combustion under atmospheric pressure, it is not suitable for combustion under high pressure, such as in gas turbine combustors. be. This is the problem.

The above methods (1), (2), and (3) are all based on homogeneous reactions only in the gas phase, but recently, as an alternative to this, heterogeneous combustion using a solid phase catalyst has been proposed. A method (hereinafter referred to as a catalytic combustion method) has been proposed. This 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 increases, resulting in the formation of a high temperature zone where the maximum temperature is low and NOx is rapidly generated. Therefore, it is possible to extremely reduce the amount of NOX l generated. Furthermore, the turbine inlet temperature remains unchanged from conventional turbines, allowing complete combustion of the fuel.

FIG. 7 is a conceptual diagram showing an example of a combustor used in a catalytic combustion system. The numbers in FIG. 7 represent the same elements as in FIG. It is a structural feature. The catalyst filling area 7 is normally filled with a combustion catalyst having a honeycomb structure, in which a mixture of fuel and air is combusted. In this system, it is not necessarily necessary to supply combustion air downstream of the catalyst filling area 7.

However, this type of combustor also has the following problems. That is, the first problem is that the temperature of the fuel gas supplied to the turbine in the combustor currently being tested is 1100 to 1200°C, and the heat resistance temperature of the combustion catalyst is about 1200°C at most. It is. In other words, when the fuel is completely combusted in the catalyst filling area 7, the temperature of the catalyst may rise to over 1200 degrees Celsius, and as a result, the catalyst may undergo thermal deterioration or thermal damage, resulting in a reduction in its function or It is a matter of loss.

The second problem is that the higher the temperature inside the catalyst-filled area 7, the higher the flow rate of the combustion gas flowing through the catalyst-filled area 7, which causes the gas pressure loss in the catalyst-filled area 7 to increase. This is a problem that reduces the efficiency of the gas turbine.

As a countermeasure to this problem, the present inventors have proposed
The fuel is divided and supplied to the upstream and downstream regions of the
hl, ratio of fuel gas and air in the upstream region (hereinafter referred to as F
/A) is defined to a predetermined value, and the temperature rise in the catalyst filling area is set below the gas phase ignition temperature in the defined F/A, but a method is developed to obtain the desired temperature in the turbine population, This has already been filed as Japanese Patent Application No. 58-229887.

However, when processing a large amount of gas fluid as in a gas turbine combustor, it is very difficult to maintain the F/A at a predetermined value, and the value usually fluctuates around the set value. What is the change in F/A?

Even if it is minute, the effect on the combustion catalyst is extremely large. In other words, although it differs depending on the type of combustion catalyst, if the F/A value is even slightly smaller than the allowable limit, catalytic combustion will not occur within the charging region, and conversely, if it becomes even slightly larger, catalytic combustion will proceed rapidly. If the catalyst temperature rises above its heat-resistant temperature, causing thermal deterioration or damage to the catalyst, or if the components of the supplied fuel change, for example, if a fuel that is easily combustible is suddenly supplied. Situations like the above also occur.

[Object of the Invention] The present invention relates to the improvement of the combustor disclosed in the above-mentioned Japanese Patent Application No. 58-2299 [17], by mutually controlling the temperature of the catalyst filling area and the F/A in the upstream area The purpose of the present invention is to provide a gas turbine combustor using a catalytic combustion method that successfully suppresses the abnormally high temperature of the catalyst and extends its life, and also reduces the pressure loss in the catalyst filling area and increases combustion efficiency. shall be.

[Summary of the Invention] The gas turbine combustor of the present invention includes: a region where fuel and air are mixed to form a first mixture; a catalyst-filled region where a portion of the first mixture is catalytically combusted;

Further, fuel is mixed with the gas flowing out from the catalyst filling area to produce a second
A gas turbine combustor comprising: a region for producing a mixture and combusting the mixture in a gas phase; a catalyst temperature detecting means disposed in the catalyst filling region; and a catalyst temperature detecting means disposed in the first mixture forming region; A mixture ratio 2g1 node means for controlling the fuel/air mixture ratio (F/A) of the first mixture based on a signal from the detection means.

In FIG. 1 which shows one structural example of the combustor of the present invention, 11 is a fuel nozzle, and 12 is an air jet port. These fuel nozzles! ■ From the air jet port, in accordance with the setting conditions of combustion gas in the gas turbine nozzle 8,
The required amount of fuel and air is injected into the dotted line area A in the figure,
A first mixture having a predetermined mixing ratio (F/A) is formed.

At this time, if the air supply is small, most of the fuel will be combusted in the catalyst filling area 11, which will be described later, because the combustion speed in the catalytic combustion reaction generally increases in proportion to the increase in fuel concentration. As a result, the catalyst temperature becomes high and thermal deterioration and thermal damage progress, and at the same time, pressure loss also increases.

Therefore, in the combustor of the present invention, not only fuel but a mixture (first mixture) obtained by diluting this "fuel to a predetermined ratio with air" is supplied to the catalyst filling area to be described later. This suppresses the high concentration of fuel in the catalytic converter region, thereby preventing the catalyst from increasing in temperature and preventing pressure loss.

Note that the fuel nozzle 11 and air jet port 12 are located in area A.
It is preferable to arrange the mixing space as far upstream as possible within the first mixture, in order to enlarge the mixing space in order to make the concentration distribution of the first mixture as uniform as possible.

A catalyst filling area B (indicated by a dotted line) filled with, for example, a honeycomb-shaped combustion catalyst 13 is disposed after the first mixture forming area A, and the first mixture is supplied here so that a part of it is Subjected to catalytic combustion.

After this catalyst filling area B, a predetermined amount of fuel is further supplied from the fuel nozzle +1a to the effluent gas containing unburned substances flowing out from the filling area B and mixed with the effluent gas, and the obtained A region C (indicated by dotted lines) is provided in which the second mixture is combusted in a gas phase.

In this structure example, catalyst temperature detection means 14 is provided in the catalyst filling area B.
and an air amount adjusting means 15 which operates in conjunction with the detecting means 14 as a mixing ratio adjusting means.

As the catalyst temperature detection means 14, for example, a thermocouple type,
Any high temperature detection method such as an infrared method may be used. The detection means 14 may be placed anywhere in the catalyst filling area B, but is preferably placed near the lowermost region where the temperature rises the most. Furthermore, the number of detection means may be one, or a plurality of detection means may be provided at required locations.

The temperature information (for example, an electric signal) obtained by this detection means 14 is transmitted to the air amount adjustment means 15, and its operation mode is determined, and the amount of air ejected into the area A is adjusted. An example of the means 15 is an electromagnetic valve.

In operation of the combustor, first, the F/A of the first mixture to be formed in region A is determined according to the condition setting of the combustion gas in the gas turbine nozzle 6.

During operation of the combustor, if this F/A decreases for some reason, the catalytic combustion of the fuel will decrease and the temperature of the catalyst-filled area B will decrease, eventually causing homogeneous combustion in area C for the gas flowing out from here. There may be cases where the temperature necessary to raise the temperature is no longer possible.

The detection means 14 detects the temperature of the combustion catalyst 13, and transmits the information signal to the air ff1yJ node means 15 to reduce the amount of air ejected from the air outlet 12 and increase the F/A.

Conversely, if F/A in area A becomes larger than the set value, the detection means! Since the catalyst temperature detected in step 4 becomes too high, in that case, the air amount adjusting means 15 is adjusted based on the temperature information.
The F/A can be lowered by increasing the amount of air supplied by activating the air conditioner.

The relationship between this F/A control, that is, the control of the amount of supplied air, and the catalyst temperature differs depending on the type of catalyst, the type of fuel, etc., so it is recommended to test these relationships in advance by experiment. , the above control operations are easily possible.

In FIG. 1, llb is a fuel nozzle and 2 is a spark plug, which are incidental elements for pre-combustion to raise the first mixture to the temperature necessary to cause catalytic combustion. This is not necessarily necessary if the combustion catalyst 13 has high activity and catalytic combustion is possible even at low temperatures.

[Example of the Invention] A combustor shown schematically in FIG. 2 was manufactured. That is, the combustion tube 21 was filled with a refractory honeycomb catalyst 22 having a length of 90 mm and a diameter of 100 mm. A platinum-platinum-rhodium thermocouple 23 was set at a position 51 points from the downstream outlet of the catalyst zone 22. 24 is an electromagnetic valve that opens and closes in response to a signal from the thermocouple 23. First, methane is supplied from conduit P1 and air is supplied from conduit P2 to mix them, and this first mixture is electrically heated to 450°C to adjust the amount of supply to area A to F/A = 0.040° catalyst area. Enter 22 11 flow rate approx. 30
It was set to 1/sec. Note that the area C is supplied with the amount of fuel supplied to the area A via P□°.

Since the honeycomb catalyst used has a heat resistance temperature of about 1100°C, when the thermocouple temperature exceeds 1000°C, the electromagnetic valve 24 is opened and the F/A of the first mixture to area A is 0.
．． I set it to be 035. Note that the catalyst temperature is 10
When the temperature is below 00° C., the valve 24 is always in the closed state fE.

The combustor was operated in this state and the change in catalyst temperature over time was measured, and the results are shown as the solid line (a) in FIG. For comparison, thermocouple 23. The result when the electromagnetic valve 24 is not provided is shown as a dotted line (b) in FIG.

As is clear from the figure, in the case of the combustor of the present invention, the catalyst temperature is stable at about 1000°C, whereas in the combustor of the comparative example, the catalyst temperature fluctuates rapidly and even at high temperatures. If the heat resistance temperature is exceeded, there is a high risk of thermal deterioration and thermal damage.

In addition, if 1ul is burned for less than 200 hours, the combustion efficiency is 98% or more in any case, and the N in the exhaust gas is reduced.
Ox was below 3 ppgz, but after 300 hours, there was almost no change in the combustor of the present invention, whereas in the comparative example, the catalyst temperature decreased to 900''C and its combustion The efficiency also dropped to 86%.

Example 2 The same procedure as in Example 1 was carried out using the apparatus of Example 1, except that propane was mixed into methane as a fuel for 20 seconds every 20 minutes so that the planting rate was 4%. Changes in catalyst temperature over time were measured. The results are shown in Figure 4. In Figure 4, the solid line (ao) is for the present invention, and the dotted line (b) is for the comparative example. Although the catalyst remained stable despite the mixing of propane, in the case of the comparative example, the catalyst temperature rose rapidly each time propane was mixed, resulting in damage and deterioration of the catalyst.

[Effect of the invention] As is clear from the above explanation, the combustor of the present invention has ■N
Less Ox generation; (1) Since the catalyst temperature and F/A are controlled mutually, it is possible to suppress abnormally high temperatures of the catalyst. ■Therefore, thermal deterioration and thermal damage of the catalyst can be prevented and the catalyst life can be maintained for a long period of time. (2) Moreover, since there is little fluctuation in catalyst temperature, high and stable combustion efficiency can be maintained, which is of great industrial value.

[Brief explanation of drawings]

FIG. 1 is a structural example of the combustor of the present invention, and FIG. 2 is a schematic diagram of the device used in the example. Figure 3. FIG. 4 is a diagram showing the change in catalyst temperature over time in each example. Figure 5 is a conceptual diagram of a normal gas turbine combustor, Figure 6 is a diagram of the relationship between fluid flow direction and temperature in the combustor of Figure 5, and Figure 7 is an example of a catalytic combustion type gas turbine combustor. It is a conceptual diagram. 1, II, lla, 1lb-Fuel nozzle, 2... Spark plug, 3... Combustion air, 4... Cooling air, 5... Dilution air, 6... Turbine nozzle, ? , 13... Combustion catalyst, 8... Swirler 112... Air jet port, ]4... Catalyst temperature detection means, +5... Air amount 3Jf'n means 1st F! 1 Fig. 2 - Fig. 3 - Kuchiku (hr) - Fig. 4 Meze-style loading (hr) ' Fig. 5

Claims (1)

[Claims] A region where fuel and air are mixed to form a first mixture; A catalyst-filled region where a portion of the first mixture is catalytically combusted; and a region where fuel is further added to the gas flowing out from the catalyst-filled region. A gas turbine combustor comprising: a region for mixing to form a second mixture and combust it in a gas phase; a catalyst temperature detection means disposed in the catalyst filling region; and a catalyst temperature detecting means disposed in the first mixture forming region. A gas turbine combustor comprising: a mixture ratio adjusting means for controlling a mixture ratio of fuel and air in the first mixture based on a signal from the catalyst temperature sensing means.