JPS59108829A - Gas turbine combustor - Google Patents

Abstract

PURPOSE:To reduce NOx and improve efficiency of combustion by detecting outflow temperature at a medium outlet to control air fuel ratio according to said temperature while regulating fuel supply downstream of the medium according to the air fuel ratio. CONSTITUTION:Outflow temperature at a medium outlet is detected by a thermometer 9. When said temperature is lower than fire point of thin fuel, an electromagnetic 10 for supplying fuel to a portion downstream of the medium is closed to reduce fuel supply from said portion and increase and air fuel raio in mixture supplied from a portion upstream of the medium. And when the temperature detected by the thermometer 19 exceeds the heat resisting temperature of the medium, said operation is reversely carried out. Thus, nitrogen oxide is reduced to improve the efficiency of combustion.

Description

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

[Technical background of the invention and its problems]

In recent years, with the depletion of petroleum and other sources of energy, there has been a growing demand for alternative energy sources, and on the other hand, there has also been a demand for efficient use of energy resources. Examples of systems that meet these demands include gas turbine steam turbine combined cycle power generation systems that use natural gas as fuel, coal gasification gas turbine steam turbine combined cycle power generation systems, etc., which are currently being studied. be.

Because Cholera's gas turbine Φ steam turbine complex cycle generation system has higher power generation efficiency than conventional steam turbine power generation systems that use fossil fuels, its production volume is expected to increase in the future. It is expected to be a power generation system that can effectively convert fuels such as natural gas and coal gasified gas into electricity.

Conventionally, a gas turbine combustor used in a gas turbine power generation system performs homogeneous combustion by igniting a mixture of fuel and air using a spark plug. An example of such a combustor is shown in FIG. 1st
In the illustrated combustor, fuel injected from a fuel nozzle 1 is mixed with combustion air 3, ignited by a spark plug 2, and combusted. Then, the combusted 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 serious problems with such conventional combustors is that a large amount of NOx gas is produced when the fuel is combusted.

The reason why the above-mentioned NOx is generated is due to the existence of a cylinder hot section during combustion of fuel. Normally, when no nitrogen components are present in the fuel, NOx is
Nitrogen in the combustion air reacts and is generated according to the formula tC shown below.

N2 + 02: 2NO The above reaction shifts to the right side as the temperature increases, and the amount of nitrogen monoxide (NO) produced increases. A portion 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. The maximum temperature inside the combustor is
Because the temperature can reach as high as 2000'O, the area around here (
In the shaded area in FIG. 2), the amount of NOx produced rapidly decreases and increases. 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 are being studied.

If the generated NOx ii can be reduced, the flue gas denitrification device can be omitted or simplified, and examples of combustion methods aimed at such a reduction in NOx include the following. Namely, (1) a method that uses steam or water injection, (2) a two-stage combustion method that introduces combustion air in two stages and combusts the fuel, and (3) an exhaust gas recirculation method. However, these methods However, it is not necessarily satisfactory (the 00 method has poor thermal efficiency because it injects steam or water). The adjustment must be made with great care, and the maximum temperature within the combustor is not yet low enough to reduce NOx emissions.Furthermore, method (3) does not work well under atmospheric pressure. However, it is unsuitable for combustion under high pressure, such as in gas turbine combustors.

All advanced combustion methods rely on homogeneous reactions only in the gas phase, but recently, a heterogeneous combustion method using an in-phase catalyst (hereinafter referred to as the -1 catalytic combustion method) has been developed. Proposed. The catalytic combustion method uses a catalyst to combust a mixture 1+ of fuel and air. According to this method, combustion can be started at a relatively low temperature, cooling air is not required, and since the amount of combustion air is increased, the maximum sieve temperature is lowered, and therefore, the generated N
It is possible to minimize the number of Ox1 crossings. Father, Turbine Man [] The temperature is no different from the conventional one, and the fuel can be fully combusted. Figure 3 is a conceptual diagram of a combustor using the catalytic combustion method, with catalyst filling.
A catalyst body with a honeycomb structure is horizontally oriented.

Incidentally, when the device or material is the same as in FIG. 1, the same reference numeral is given. Figure 4 shows the temperature distribution within the combustor of each cell in the above hr2 gas turbine combustor: a: conventional combustion method, b: two-stage combustion method, c: catalytic combustion method. It is. In the catalytic combustion method, the maximum iQl temperature is lower than other methods, and a heterogeneous combustion reaction occurs gradually from a low temperature, and combustion progresses with a homogeneous combustion reaction halfway through. I understand.

In the catalytic combustion type combustor currently being considered,
The heat resistance of the catalyst used is about 1200°0 at most. However, since the temperature of the combustion gas supplied from the combustor to the turbine is 1,100 to 1,200° C., complete combustion of the fuel within the catalyst body results in deterioration of the catalyst and thermal damage to the fusion medium. Furthermore, the higher the gas temperature within the catalyst body, the higher the gas flow rate passing through the catalyst body, which increases the pressure loss within the catalyst body, causing a reduction in the efficiency of the gas turbine.

As a countermeasure for this, when the temperature of the fuel-air mixture rises to a certain degree, combustion proceeds smoothly even with a catalyst with low catalytic activity.
A method to prevent heat damage to the catalyst body by placing a highly active catalyst in the rear stage and a catalyst with low activity but good heat resistance, or to supply fuel to the combustor by placing a catalyst upstream and downstream of the catalyst body. A method of adjusting the F/A on the upstream side of the catalyst so that the adiabatic flame temperature is below the allowable temperature of the catalyst, and finally supplying fuel downstream of the catalyst to obtain the desired temperature. is being considered.

However, the activity of the catalyst generally decreases over time, which slows down the reaction rate of catalytic combustion, and because the fuel and air mixture does not rise to the temperature within the catalyst body that would burn without a catalyst, the fuel is not completely combusted and the turbine Not only is it impossible to obtain the desired outflow velocity and temperature at the inlet, but a large amount of unburned fuel is released into the atmosphere.

[Purpose of the invention]

The purpose of the present invention is to provide catalytic combustion with extremely high combustion efficiency, which eliminates the above-mentioned problems, prevents the catalyst from becoming hot, extends the life of the catalyst, and reduces pressure loss within the catalyst. The object of the present invention is to provide a gas turbine combustor of the same type.

[Outline of the Invention] The gas turbine combustor of the present invention supplies fuel to the upstream and downstream parts of the catalyst body, and the mixture of air and fuel supplied upstream of the catalyst body passes through the catalyst body. It is characterized by detecting the temperature of the catalyst and adjusting the amount of fuel supplied to the upstream and downstream parts of the catalyst according to the detected temperature.

1'J, below, the invention will be explained in more detail with the aid of the figures. FIG. 5 shows an example of the present invention.

Once the combustion gas conditions in the gas turbine nozzle 6 are set, the necessary fuel and air values per unit time are determined. If all the fuel is supplied only from the fuel nozzle 1 in the early stage when the catalyst activity is high, all the fuel will be burned inside the catalyst body. That is, the temperature reaches within the catalyst body, causing damage to the catalyst due to heat. Furthermore, as the temperature of the mixture increases, the rate of passage through the catalyst body increases and the pressure loss within the catalyst body increases. Also,
Passing a large amount of fuel through the catalyst body also increases pressure loss within the catalyst body. Therefore, in the present invention,
First, the predetermined fuel is divided into upstream and downstream parts of the catalyst body, and the amount of fuel passing through the catalyst body is minimized.
A process is used to reduce pressure loss within the catalyst body.

In the early stage when the activity of the catalyst is high, catalytic combustion easily occurs even if the F/A of the air and fuel passing through the catalyst body is small to some extent, and the temperature of the effluent at the outlet of the catalyst body rises sufficiently to the ignition point of the lean fuel. , the mixture produced by being supplied from the fuel nozzle 8 downstream of the catalyst body can be combusted.

However, when the activity of the catalyst decreases, if the F/A passing through the catalyst is small, catalytic combustion will not be sufficient, and the temperature of the effluent at the outlet of the catalyst will not rise to the ignition point of the lean fuel, and the fuel will be supplied from the downstream part of the catalyst. The resulting mixture cannot be combusted, resulting in incomplete combustion.

Generally, the speed of the catalytic combustion reaction increases as the fuel concentration increases, so if the catalytic activity decreases, increasing the F/A that passes through the catalytic body will raise the temperature of the mixture at the outlet of the catalytic body to the ignition point of the lean fuel. Can be stirred up. Here, increase F/A to 71! Except for this, the temperature must be adjusted so that the temperature of the effluent at the outlet of the catalyst is below the heat-resistant temperature of the catalyst. Here, the ignition point of the lean fuel must be determined in advance by experiment. therefore,
The temperature of the effluent at the outlet of the catalyst is detected by a thermometer 9, and if the temperature is lower than the ignition point of the lean fuel, the electromagnetic valve 10 for supplying fuel to the downstream part of the catalyst is closed, and the fuel from the downstream part of the catalyst is stopped. What is necessary is to reduce the supply amount and increase the F/A of the mixture supplied from the upstream part of the catalyst body. If the temperature measured by the thermometer 9 exceeds the allowable temperature limit of the catalyst, the previous operation may be reversed. Note that here, an example of the present invention has been shown for the case where one catalyst body is used, but when two catalyst bodies are used,
The same applies to the case where there are more than one catalyst body, but in this case, the fuel supply port and temperature detection may be provided at all or several locations of each catalyst body outlet.

〔Effect of the invention〕

The gas turbine combustor of the present invention is capable of efficiently burning fuel by catalytic combustion and with almost no NOx generation, and has a long lifespan and a low pressure inside the catalyst body. This reduces losses.

[Embodiments of the invention]

The catalyst body uses a honeycomb structure with a length of 150 mm.
A ceramic short body with a diameter of 25.4111 mm and a diameter of 25.4111 mm was used, and 2 wt % of Pt was supported as a catalyst.

This honeycomb catalyst body was filled into a combustion tube having a diameter of 26", and using methane as fuel, a mixture of methane and air was heated to 500°C, and the total supply amount was 3.
00Ω/min (F'/A=0.035). Then, the temperature distribution inside and outside the catalyst body and the concentration of unresolved methane in the turbine nozzle were measured with respect to fuel supply and the catalyst.

As a result, at the initial stage of the catalyst, the temperature inside the catalyst body (I exceeded 11 (10'Q) (d), and the methane concentration at the turbine nozzle was less than 10 ppm, but after heat treatment at 1000°C for 100 hours, If you do, 1r is enough
No uptake was obtained ('@-f7 (De)) and the methane frugality at the turbine nozzle was also over 10,000 ppm.

On the other hand, in this case, even when using a catalyst body heat-treated at 1000°0 for 100 hours, the F/
When A is set to 0.032 and the remainder is supplied from the outlet of the medium, a temperature rise of approximately 950'O is obtained at the outlet of the catalyst body, and uniform combustion of the mixture occurs downstream, and the temperature rises by more than 1100γ]. The methane key level at the turbine nozzle is also 10p.
It was confirmed that it was below pm.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram of a normal gas turbine combustor, Figure 2 d
, Diagram showing weekly gas turbine combustor temperature distribution, 3rd
The figure is a conceptual diagram of a catalytic combustion type gas turbine combustor.
The figure shows temperature distributions in a conventional gas turbine combustor (a), a two-stage gas turbine combustor (b), and a catalytic combustion type gas turbine combustor (c), and Fig. 5 shows a catalyst according to the present invention. Figure 6, a conceptual diagram of a combustion type Kasturbine combustor, shows the case where a No. 31 type combustor is used.
In the early stage of the catalyst (a), the catalyst body'f was heat-treated at 1000'O for t00 hours: (e), and in the case of using the combustor of the present invention, it was heat-treated at 1000'O for 10.0 hours. A diagram showing the temperature distribution inside and outside the catalyst body in case (f) when the catalyst body is used is shown below. 1.8...Fuel nozzle, 2...Spark plug, 3
... Combustion air, 4... Cooling air, 5... Dilution air, 6... Turbine nozzle, 7... Catalyst body,
9...Thermometer, 10...Solenoid valve. Agent: Patent attorney: Noriyuki Chika (and 1 other person) Figure 1: Tenkei-nada Mokugata 1st scale ml Takumi Kusei

Claims (1)

Claims: Passing the first mixture through a catalyst to leave and combust at least a portion of the first mixture of fuel and air; further supplying fuel to the catalyst outlet effluent; In a catalytic combustion gas turbine combustor forming a second mixture and uniformly combusting the second mixture to produce a gas effluent, a. sensing a catalyst outlet effluent temperature; b.
a step of changing the fuel concentration in the first mixture according to the temperature of the effluent on the previous day, and adjusting the ratio of fuel to air (hereinafter referred to as F/A) in the first mixture; c, hσ; A gas turbine combustor comprising a step of adjusting the amount of fuel supplied downstream of the catalyst for producing the second mixture according to F/A.