DETAILED DESCRIPTION OF THE INVENTION
 The present invention relates to a low calorie gas.
Low for gas turbines capable of stable combustion and reducing NOx
It relates to a NOx combustor.
2. Description of the Related Art In recent years, gas turbines have been
NOx (nitrogen oxides) in flue gas by combustion
Is required. As a result,
Low NOx combustors for bins use a premixed lean burn system.
Main burners that perform lean burn and diffusion
Combination with pilot burner that performs flame holding by combustion method
Matching was mainly used.
In such a premixed lean burn type combustor,
Premix fuel with sufficient air in the main burner.
This causes lean burn of the hot spot.
And eliminates high-temperature flames and achieves low NOx
However, premixed lean fuel
In a combustion type combustor, the fuel and air are well mixed.
It is necessary to generate NOx in areas where the fuel concentration is excessively high.
The production amount increases, and conversely, the combustion temperature
There is a problem that the temperature is low and unburned gas is generated. Also,
The mixture is spontaneously ignited because the mixture is premixed with air
If there is a risk of flashback and these occur, NOx
It causes a sudden increase, oscillating combustion, etc., and the performance only deteriorates.
However, there was also a risk of damaging the equipment.
 The problems of the premixed lean burn combustor described above
To solve the problem and achieve low NOx, FIG.
"Low NOx burner for gas turbine" has been proposed
 The low NOx burner is a first air swirler.
1. The cross section is connected to the first air swirler and the cross section is reduced toward the outlet.
A first air passage 2 which is small or subsequently enlarged, said first air passage
Fuel nozzle for injecting fuel into an airflow flowing through the inside
3. Installed on the outer periphery of the first air passage coaxially with its outlet.
Attached second air swirler 4, the second air swirler
Multiple passages in an annular passage partitioned by vessel blades
Second air passage 5 and air flowing through the second air passage.
With a second fuel nozzle 6 for injecting fuel into the airflow
However, this low NOx burner has the following problems.
There was a title.
(1) Violation by the first air swirler 1 and the second air swirler 4
The turbulence promotes the mixing of air and fuel, causing a pressure drop
(2) Two air passages for combustion (first air passage 2 and first air passage 2)
2) The air swirler 4) makes it difficult to distribute the air flow.
(3) Each according to the amount of air flowing through the two air passages
Need to control the fuel flow and optimize both combustion
As a result, operation control for achieving low NOx is complicated.
(4) The overall structure is complicated.
The present invention has been made in order to solve such a problem.
It was created. That is, the main object of the present invention is to
Spontaneous ignition, flashback, oscillating fuel of premixed lean-burn mixture
Problems such as baking can be essentially solved and pressure loss is small.
Control of air flow and fuel flow is easy, and the structure is simple.
Clean and low NOx equivalent to premixed lean burn
To provide a low NOx combustor for gas turbines
is there. Another object of the present invention is to provide a biomass gas.
It can be applied to low flame-retardant low calorie gas fuel.
For gas turbines that can achieve low NOx and stable combustion
It is to provide a low NOx combustor.
According to the present invention, a central portion is provided.
And has a central fuel injection port (11) at the tip
The central fuel injection pipe (12) and the central fuel injection pipe are spaced apart.
Forming a combustion air flow path (13) therebetween
Annular duct (14) and expands gas exiting the air passage
And a combustion chamber (16) for performing the combustion.
The air flow path (13) gradually increases after the flow path area gradually decreases, during which time
A throat portion (13a), and
Having a throat injection port (15) for injecting a charge
A low NOx combustor for a gas turbine is provided.
According to the configuration of the present invention, the combustion air flow
A central injection port for the combustion air passing through the passage (13)
Inject fuel from (11) and throat injection port (15)
And disperse the fuel injection to make the fuel concentration uniform,
xEmissions can be reduced and combustion efficiency can be improved
That is, a single combustion air passage (13)
Between the central fuel injection pipe (12) and the annular duct (14)
It is easy to control the air flow rate because it is formed between
is there. In addition, the combustion air flow path (13) has a gradually increasing flow path area.
It gradually increases after decreasing and has a throat portion (13a) between
The fuel is injected into the throat of the
Shut down and mix the airflow and fuel efficiently.
Thus, NOx can be reduced. Also, only with the air swirler,
The pressure loss is small as compared to forming turbulence. further,
Fuel from central injection port (11) and throat injection port (15)
Since the fuel forms a flame at almost the same position, the fuel flow rate
Easy to control.
Further, the combustion chamber (16) has an air passage.
The throat injection port (15)
The combustion speed and the flow velocity match at a position away from
A flame can be formed stably. Furthermore, its mixing efficiency is high,
Simple structure, comparable to premixed lean burn
It was confirmed in Examples that NOx can be reduced. further
For flame-retardant low-calorie gas fuels such as biomass gas
In the meantime, the fuel can be maintained from the central injection port (11) using ordinary fuel.
Flame, low calorie gas fuel from throat injection port (15)
By injecting low calorie gas fuel
It can be stably burned.
According to a preferred embodiment of the present invention,
The combustion chamber (16) gradually removes gas exiting the air passage.
An annular tapered portion (16a) extending in an annular shape in the
An annular recess forming an annular recess with the duct (14)
With this configuration, the throat injection port (15)
The flame burned at a position away from the
The position where the combustion speed and the flow velocity are gradually decelerated in a)
In addition, a floating flame can be formed stably. Also, annular concave
The combustion products (H TwoO, COTwo, Etc.) Lisa
Since curation can be performed, NOx reduction can be realized.
 Further, the combustion air flow path (13)
It has a swirler (13b) for giving a swirling flow to the burning air flow.
With this configuration, the combustion air flow path (13)
A swirl flow can be given to the combustion air flow of
Dispersion of fuel, uniform fuel concentration, suppression of NOx emissions, fuel
The baking efficiency can be more effectively improved.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described.
Will be described with reference to the drawings. In addition, in each figure,
The same reference numerals are given to the same parts, and the duplicated description will be omitted.
FIG. 1 shows a low NOx fuel for a gas turbine according to the present invention.
It is a whole block diagram of a baking machine. As shown in FIG.
Low NOx combustor 10 for gas turbines
Tube 12, annular duct 14, and combustion chamber chamber 16
The center fuel injection pipe 12 has a tip (the right end in the figure)
Is a closed hollow cylindrical tube, and the center of the low NOx combustor 10
Located in the department. Also, the tip of the central fuel injection pipe 12
Central injection port 1 for injecting fuel into combustion chamber 16
The fuel injected at the central injection port 11 will be described later.
The same gas fuel as the fuel injected at the throat injection port 15
(For example, LNG). Also, especially
The fuel injected at the funnel injection port 15 is biomass gas.
Flame-retardant low-calorie gas fuel such as
In order to actually perform the fuel injection,
It is better to use a gaseous fuel with good flammability (for example, LNG)
No. The fuel injection direction of the center injection port 11 is shown in this figure.
To a floating flame formed in the combustion chamber 16
It is good to be obliquely outward.
The annular duct 14 connects the central fuel injection pipe 12
Enclose them at intervals and form a combustion air passage 13 between them
I do. The combustion air passage 13 is formed after the passage area gradually decreases.
It is formed smoothly so as to gradually increase, while the flow area is
It has the smallest throat portion 13a. Also throat
Passes through the combustion air passage 13 upstream of the portion 13a.
A swirler 13b for providing a swirling flow to the combustion air flow is provided.
The throat portion 13a of the annular duct 14
Inject fuel toward the throat 13a in the area surrounding
A throat injection port 15 is provided. This throat squirt
The fuel injection direction of the outlet 15 is slow as shown in this figure.
It is good to be obliquely inward toward the opening 13a.
The central injection port 11 and the throat injection port 1
The relative position of 5 is a throat injection
It is preferred that the outlet 15 is located slightly upstream,
It may be a relation position. In addition, the injection of throat injection port 15
The exit position is preferably the throat 13a, but slightly downstream
May be placed.
The combustion chamber 16 is provided with the air exiting the air passage.
An annular tapered portion 16 that gradually expands the body (air-fuel mixture) in an annular shape
a, the air-fuel mixture exiting the air passage is evenly expanded and reduced.
Speed up. Further, the annular duct 14 and the annular tapered portion 16a
An annular concave portion 16b forming an annular concave portion therebetween,
Combustion products (HTwoO, COTwo, Etc.)
It is supposed to.
According to the configuration of the present invention described above, the combustion air
The air flow path 13 gradually increases after the flow path area gradually decreases,
A throat portion for injecting fuel into the throat portion.
Therefore, flashback can be effectively prevented, and airflow and fuel
Since mixing can be performed efficiently, NOx can be reduced. Also,
Compared to forming a severe turbulence with the air swirler alone,
Loss can be reduced. Furthermore, the central injection port 11 and throat
Fuel from injection port 15 forms floating flame 7 at almost the same position
Control of combustion air and fuel flow rate is easy.
The combustion chamber chamber 16 exits the air passage.
Gas (mixture) is evenly expanded, so throat injection
At a position distant from the outlet 15, the combustion velocity and the flow velocity match,
Played flame 7 can be formed stably. Furthermore, its mixed effect
High efficiency, simple structure, and premixed lean burn system
NOx reduction comparable to
In addition, low flame retardancy such as biomass gas
For calorie gas fuel, more general than central injection port 11
Holds flame using fuel, low calorie from throat injection port 15
-Low-calorie gas fuel by injecting gas fuel
However, stable combustion can be achieved.
FIG. 2 shows a low NOx fuel for a gas turbine according to the present invention.
FIG. 3 is a configuration diagram showing an embodiment of a baking apparatus, and FIG.
It is a performance comparison figure in an example. The fuel of the present invention shown in FIG.
The following four combustion tests were performed using the same fuel
A: Upstream (premixing): combustion air flow path
Lean combustion premixed with air and fuel upstream of 13
B: center: expanded fuel injected only from central injection port 11
C: Outer circumference 1 ... fuel injection only from throat injection port 15
D: Outer circumference 2... Only from the downstream side of throat injection port 15
Diffusion combustion with fuel injection
In FIG. 3, the horizontal axis is the combustor outlet temperature and the vertical axis is
Is the generated NOx amount. The four curves in the figure are
It is a test result corresponding to AD. From this figure, the conventional
Combustor outlet temperature almost equal to the premixed lean burn system (A)
In the case of only the throat injection port 15 of C (outer circumference 1)
In this case, it can be seen that the generated NOx amounts are also substantially equal. Also,
At B (center) and D (perimeter 2), lower combustor exit temperature
It is the same level of generated NOx
Understand. Therefore, B (center) and C (outer circumference 1) or D
Low NOx fuel of the present invention corresponding to the combination of (outer circumference 2)
Problems such as spontaneous ignition of the mixture, flashback, oscillating combustion, etc.
Not only can be essentially solved, but also the mixed lean burn method
It can be seen that NOx reduction comparable to that of the above can be achieved.
The present invention is not limited to the above-described embodiments and examples.
The invention is not limited thereto, and various modifications may be made without departing from the gist of the present invention.
Of course, it can be changed.
As described above, according to the present invention, the burner flow
Central and peripheral burner throat or
Inject fuel from the downstream, disperse the fuel injection, and concentrate the fuel.
Level, reducing NOx emissions and improving combustion efficiency
Improve. It also has low flame retardancy such as biomass gas.
For calorie gas fuel, use general fuel from the center
To keep flame and inject low calorie gas fuel from the outer periphery
Thereby, stable combustion can be achieved.
Therefore, the low NOx for gas turbine of the present invention
The combustor uses a premixed lean-burn type air-fuel mixture
Problems such as fire and vibration combustion can be essentially solved, and
Low loss, easy control of air flow and fuel flow,
Simple structure, low N comparable to premixed lean burn
Can be converted to Ox and flame retardant like biomass gas
Of low calorie gas fuel
Has excellent effects such as being able to achieve Oxification and stable combustion
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of a low NOx combustor for a gas turbine of the present invention. FIG. 2 is a configuration diagram showing an embodiment of a low NOx combustor for a gas turbine of the present invention. FIG. 3 is a performance comparison diagram in the example of the present invention. FIG. 4 is a configuration diagram of a conventional low NOx combustor. [Description of Signs] 1 first air swirler, 2 first air passage, 3 first fuel nozzle, 4 second air swirler, 5 second air passage, 6
2nd fuel nozzle, 7 floating flame, 10 low NOx combustor for gas turbine, 11 central injection port, 12 central fuel injection pipe, 13 combustion air flow path, 13a throat section, 1
3b swirler, 14 annular duct, 15 throat injection port, 16 combustion chamber chamber, 16a annular taper portion,
16b annular recess