JP2024067366A - Gas Turbine Combustor - Google Patents

Abstract

[Problem] To effectively cool the inner wall of a combustion chamber while satisfactorily mixing combustion gas and air in the combustion chamber. [Solution] A gas turbine combustor is capable of burning the fuel gas and air mixed in the combustion chamber with a burner. The burner includes a first fuel gas nozzle, a second fuel gas nozzle, and a first air nozzle. The first fuel gas nozzle injects fuel gas from a first fuel gas supply system connected to a fuel gas supply source for supplying fuel gas into the combustion chamber as a first fuel gas. The second fuel gas nozzle is disposed radially inward from the first fuel gas nozzle, and injects fuel gas from a second fuel gas supply system connected to the fuel gas supply source into the combustion chamber as a second fuel gas. The first air nozzle is disposed radially outward from the first fuel gas nozzle, and injects air into the combustion chamber. [Selected Figure] FIG.

Description

This disclosure relates to a gas turbine combustor.

For example, a gas turbine for driving a generator in a power generation plant is driven by combustion gas produced by mixing and burning fuel gas and air in a gas turbine combustor. The fuel gas used in this type of gas turbine combustor may be a so-called low-calorie gas with a relatively low calorific value, such as blast furnace gas produced during steelmaking in a steel plant. Low-calorie gas is a flame-retardant gas with a slow burning rate due to its low calorific value, but it also has the advantage of producing less NOx emissions during combustion, and effective use of this gas is being considered.

For example, Patent Document 1 discloses a gas turbine combustor that uses liquefied natural gas (LNG), a high-calorie gas, in addition to stably burning low-calorie fuel gas such as low-calorie gas. This document further proposes a configuration in which the low-calorie fuel gas is divided into two systems and supplied to the inner and outer swirlers of the combustor, respectively, and in the inner swirler, fuel gas nozzles for injecting fuel gas into the combustion chamber and air nozzles for injecting air into the combustion chamber are arranged alternately along the circumferential direction.

JP 2014-52088 A

In the above-mentioned Patent Document 1, low-calorie gas is supplied to both the inner and outer swirlers of the combustor, but air nozzles are provided only in the inner swirler. Therefore, while the low-calorie gas can be mixed well with the air in the inner swirler, there is a risk that it may be difficult to mix the low-calorie gas supplied to the outer swirler well with the air because no air nozzles are provided in the outer swirler.

In addition, in the configuration of Patent Document 1, the air nozzle is located in the inner swirler, so the air from the air nozzle is ejected to a position away from the inner wall that constitutes the combustion chamber. As a result, the inner wall that constitutes the combustion chamber is not easily cooled by the air from the air nozzle, and there is a risk that the temperature of the inner wall of the combustion chamber will rise.

At least one embodiment of the present disclosure has been made in consideration of the above circumstances, and aims to provide a gas turbine combustor that can effectively cool the inner wall of the combustion chamber while satisfactorily mixing the combustion gas and air in the combustion chamber, and a method for controlling the gas turbine combustor.

In order to solve the above problems, a gas turbine combustor according to at least one embodiment of the present disclosure has:
A gas turbine combustor capable of combusting fuel gas and air mixed in a combustion chamber with a burner disposed upstream of the combustion chamber,
The burner is
a first fuel gas nozzle for injecting the fuel gas as a first fuel gas from a first fuel gas supply system connected to a fuel gas supply source for supplying the fuel gas into the combustion chamber;
a second fuel gas nozzle arranged radially inward from the first fuel gas nozzle and configured to inject the fuel gas as a second fuel gas from a second fuel gas supply system connected to the fuel gas supply source into the combustion chamber;
a first air nozzle arranged radially outward from the first fuel gas nozzle and configured to inject the air into the combustion chamber;
Equipped with.

At least one embodiment of the present disclosure provides a gas turbine combustor that can effectively cool the inner wall of a combustion chamber while favorably mixing the combustion gas and air in the combustion chamber, and a method for controlling the gas turbine combustor.

FIG. 1 is an overall configuration diagram of a gas turbine combustor according to a first embodiment. 2 is a view showing a burner of the gas turbine combustor of FIG. 1 from the axial downstream side. FIG. FIG. 2 is a block diagram showing an internal configuration of the control device shown in FIG. 1 . 2 is a flowchart showing a method for controlling a gas turbine combustor implemented by the control device of FIG. 1 . 5 is a graph showing the behavior of the nozzle differential pressure or fuel flow rate with respect to the heat generation amount of the fuel gas in FIG. 4 . FIG. 5 is a diagram showing an operation state of the gas turbine combustor of FIG. 1 in step S103 of FIG. 4 . FIG. 5 is an overall configuration diagram of a gas turbine combustor according to a second embodiment. 8 is a view showing a burner of the gas turbine combustor of FIG. 7 from the axial downstream side. 8 is a flowchart illustrating a method for starting up the gas turbine combustor of FIG. 7. 10 is a graph showing the behavior of nozzle differential pressure with respect to load of a gas turbine started by the start-up method of FIG. 9 .

Below, several embodiments of the present invention will be described with reference to the attached drawings. However, the configurations described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention and are merely illustrative examples.

First Embodiment
FIG. 1 is an overall configuration diagram of a gas turbine combustor 1A according to a first embodiment, and FIG. 2 is a diagram showing a burner 22 of the gas turbine combustor 1A of FIG. 1, viewed from the axial downstream side.

First, as shown in FIG. 1, the gas turbine combustor 1A generates combustion gas for driving a gas turbine by mixing and burning fuel gas Gf and air Ga. The gas turbine combustor 1A has a combustion chamber 20 for mixing and burning the fuel gas Gf and air Ga, and a burner 22 provided upstream of the combustion chamber 20. The fuel gas Gf and air Ga mixed in the combustion chamber 20 are ignited by the burner 22, and are burned by the flame to generate combustion gas.

The gas turbine combustor 1A includes a fuel gas supply system 10 for supplying fuel gas Gf. The fuel gas Gf is a so-called low-calorie gas that has a relatively low calorific value. In this embodiment, blast furnace gas (BFG) generated during steelmaking in a steelmaking plant is used as the low-calorie gas, but coal gasification gas, biomass gas, etc. may also be used. The calorific value of the low-calorie gas may be adjusted by adding a high-calorie gas with a relatively high calorific value. The high-calorie gas may be, for example, coke oven gas (COG), liquefied natural gas (LNG), city gas, etc.

The fuel gas supply system 10 includes a fuel gas supply source 12 capable of supplying fuel gas Gf, and a first fuel gas supply system 10a and a second fuel gas supply system 10b connected to the fuel gas supply source 12. The first fuel gas supply system 10a and the second fuel gas supply system 10b have a common fuel supply source 12 and are configured to be able to supply fuel gas Gf as first fuel gas Gf1 and second fuel gas Gf2 to the first fuel system 14a and the second fuel system 14b of the gas turbine combustor 1A, respectively.

Figure 1 shows an example of the configuration of such a fuel gas supply system 10. Specifically, one end of a fuel gas main line 16 is connected to the fuel gas supply source 12. The other end of the fuel gas main line 16 branches into a first fuel gas branch line 18a of the first fuel gas supply system 10a and a second fuel gas branch line 18b of the second fuel gas supply system 10b. The first fuel gas branch line 18a and the second fuel gas branch line 18b are connected to the first fuel system 14a and the second fuel system 14b of the gas turbine combustor 1A, respectively.

The first fuel gas branch line 18a and the second fuel gas branch line 18b are provided with a first flow rate adjustment valve Vr1 and a second flow rate adjustment valve Vr2, respectively. The opening degree of the first flow rate adjustment valve Vr1 and the second flow rate adjustment valve Vr2 can be controlled based on a control signal from the control device 100 described below, and the flow rates of the first fuel gas Gf1 and the second fuel gas Gf2 in the first fuel gas supply system 10a and the second fuel gas supply system 10b can be independently adjusted.

The gas turbine combustor 1A also includes an air supply system 24 for supplying air Ga. The air Ga may be air taken in from the outside, or compressed air generated by compressing air using a compressor (not shown).

The burner 22 includes a first fuel system 14a and a second fuel system 14b. The first fuel system 14a has a first fuel gas nozzle 24a on its downstream side, and the first fuel gas Gf1 supplied by the first fuel gas branch line 18a of the first fuel gas supply system 10a can be ejected into the combustion chamber 20. The second fuel system 14b has a second fuel gas nozzle 24b on its downstream side, and the second fuel gas Gf2 supplied by the second fuel gas branch line 18b of the second fuel gas supply system 10b can be ejected into the combustion chamber 20.

As shown in FIG. 2, the first fuel gas nozzle 24a and the second fuel gas nozzle 24b are formed between a plurality of cylindrical members 23a, 23b, and 23c, each of which has a substantially cylindrical shape and extends continuously along the circumferential direction. The cylindrical member 23b has a larger diameter than the cylindrical member 23a, and the cylindrical member 23c has a larger diameter than the cylindrical member 23b. These cylindrical members 23a, 23b, and 23c are arranged concentrically with each other. The first fuel gas nozzle 23a is formed between the cylindrical members 23b and 23c (i.e., the cylindrical member 23b is configured as the inner cylinder and the cylindrical member 23c is configured as the outer cylinder). The second fuel gas nozzle 23b is formed between the cylindrical members 23a and 23b (i.e., the cylindrical member 23a is configured as the inner cylinder and the cylindrical member 23b is configured as the outer cylinder). The first fuel gas nozzle 24a is located radially outside the second fuel gas nozzle 24b.

The first fuel gas nozzle 24a and the second fuel gas nozzle 24b may be provided with swirlers 31a and 31b, respectively, for forming a swirling flow of the fuel gas injected into the combustion chamber 20. In FIG. 2, as an example of the swirlers 31a and 31b, a plurality of inclined plate-shaped members are arranged in the circumferential direction, and the fuel gas is injected from the discharge holes formed between the adjacent plate-shaped members, forming a swirling flow in the combustion chamber 20. The configuration of the swirler 31c is merely one example, and for example, the shape of the hole for discharging the fuel gas into the combustion chamber 20 may be a circle, an ellipse, a square, an annular shape, etc.

The relationship in size between the flow passage areas of the first fuel gas hole 24a and the second fuel gas hole 24b is not limited, but for example, the first fuel gas hole 24a may have a flow passage area larger than that of the second fuel gas hole 24b. In this case, the flow rate of the first fuel gas Gf1 ejected from the first fuel gas hole 24a closer to the first air hole 24c becomes larger than the flow rate of the second fuel gas Gf2 ejected from the second fuel gas hole 24b farther from the first air hole 24c, which can facilitate the mixing of the first fuel gas Gf1 with the air Ga ejected from the first air hole 24c.
The flow passage area of the nozzle hole means the cross-sectional area of the outlet portion of the nozzle hole (on the combustion chamber 20 side) or the cross-sectional area of the narrowest portion between the inner and outer cylinders that constitute the nozzle hole.

The burner 22 also has a first air nozzle 24c for ejecting air Ga supplied from the air supply system 24 into the combustion chamber 20. Such a first air nozzle 24c is provided radially outward from the first fuel gas nozzle 24a. In this embodiment, the first air nozzle 24c is provided adjacent to the first fuel gas nozzle 24a radially outward. This reduces the distance between the first fuel gas nozzle 24a and the first air nozzle 24c, allowing the first fuel gas Gf1 ejected from the first fuel gas nozzle 24a and the air Ga ejected from the first air nozzle 24c to be mixed well in the combustion chamber 20.

In addition, by providing the first air hole 24c radially outward from the first fuel gas hole 24a and the second fuel gas hole 24b, the distance between the first air hole 24c and the inner wall 20a of the combustion chamber 20 downstream of the burner 22 is reduced. Therefore, the air ejected from the first air hole 24c can promote cooling of the inner wall 20a of the combustion chamber 20, and the temperature of the inner wall constituting the combustion chamber 20 can be effectively reduced.

As shown in FIG. 2, the first air nozzle 24c is formed between the cylindrical members 23c and 23d (i.e., the cylindrical member 23c is the inner cylinder and the cylindrical member 23d is the outer cylinder) which extend continuously in the circumferential direction. The cylindrical member 23d has a larger diameter than the cylindrical member 23c, and the cylindrical members 23c and 23d are arranged concentrically with each other. The first air nozzle 24c thus formed is provided adjacent to the first fuel gas nozzle 24a on the radially outer side. This makes it possible to mix the air ejected from the first air nozzle 24c well with the first fuel gas Gf1 and the second fuel gas Gf2 ejected from the first fuel gas nozzle 24a and the second fuel gas nozzle 24b located on the radially inner side, while avoiding a complicated structure. In particular, by providing the first air nozzle 24c radially outward from the first fuel gas nozzle 24a, the distance between the first air nozzle 24c and the first fuel gas nozzle 24a is shortened, and the air Ga can be mixed well with the first fuel gas Gf1 ejected from the first fuel gas nozzle 24a. In addition, by providing the first air nozzle 24c between the cylindrical members 23c and 23d that extend continuously in the circumferential direction, it is possible to cool a wide range of the inner wall 20a that constitutes the combustion chamber 20 by the air Ga ejected from the first air nozzle 24c.

The first air hole 24c may be provided with a swirler 31c for forming a swirling flow of air injected into the combustion chamber 20. In FIG. 2, as an example of the swirler 31c, a plurality of inclined plate-shaped members are arranged in the circumferential direction, and a swirling flow is formed in the combustion chamber 20 by ejecting air from an ejection hole formed between adjacent plate-shaped members. This configuration of the swirler 31c is merely one example, and for example, the shape of the hole for ejecting air into the combustion chamber 20 may be a circle, an ellipse, a square, a ring, etc.

The gas turbine combustor 1A having the above configuration can operate based on a control signal from a control device 100, which is a control unit of the gas turbine combustor 1A. The control device 100 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, for example, and the CPU reads this program into the RAM or the like and executes information processing and arithmetic processing to realize various functions. The program may be installed in a ROM or other storage medium in advance, provided in a state stored in a computer-readable storage medium, or distributed via a wired or wireless communication means. The computer-readable storage medium may be a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

FIG. 3 is a block diagram showing the internal configuration of the control device 100 shown in FIG.
The vehicle driving apparatus includes an operating state acquisition unit 102 and a control unit 104 .

The operating state acquisition unit 102 is configured to acquire the operating state of the gas turbine combustor 1A. The operating state acquired by the operating state acquisition unit 102 includes at least the heat value C of the fuel gas or the load of the gas turbine 1.

The control unit 104 is configured to control each valve provided in the fuel gas supply system 10 based on at least one of the heat value C of the fuel gas included in the operating state acquired by the operating state acquisition unit 102 or the load L of the gas turbine to which the combustion gas generated by the gas turbine combustor 1A is supplied. The control method of each valve by the control unit 104 will be specifically described below. FIG. 4 is a flowchart showing the control method of the gas turbine combustor 1A performed by the control device 100 of FIG. 1, FIG. 5 is a graph showing the behavior of the nozzle differential pressure ΔP or the fuel flow rate with respect to the heat value C of the fuel gas Gf of FIG. 4, and FIG. 6 is a diagram showing the operating state of the gas turbine combustor 1A of FIG. 1 in step S103 of FIG. 4.

The operating state acquisition unit 102 acquires the operating state of the gas turbine combustor 1A (step S100). As described above, the operating state acquired in step S100 includes at least one of the heat generation amount C of the fuel gas, the nozzle differential pressure ΔP (the differential pressure in the fuel injection nozzle including the first fuel gas nozzle 24a and the second fuel gas nozzle 24b), the flow rate of the fuel gas, or the load L of the gas turbine (not shown) driven by the combustion gas generated in the gas turbine combustor 1A.

Then, the control unit 104 determines whether or not a predetermined operating condition is satisfied based on the operating state acquired in step S100 (step S101). In step S101, it is determined whether or not at least one parameter included in the operating state acquired in step S100 satisfies a threshold value previously set as an operating condition. In this embodiment, as an example, attention is focused on the heat value C of the fuel gas Gf, which is one of the parameters included in the operating condition, and in step S101, it is determined whether or not the heat value C of the fuel gas Gf is less than a threshold value Cref.

When the operating state satisfies the predetermined operating conditions (step S101: YES), the control unit 104 controls the first flow rate control valve Vr1 so that the first fuel gas Gf1 is supplied from the first fuel gas supply system 10a to the first fuel gas nozzle 24a, and controls the second flow rate control valve Vr2 so that the second fuel gas Gf2 is supplied from the second fuel gas supply system 10b to the second fuel gas nozzle 24b (step S102). That is, in step S102, each valve of the fuel gas supply system 10 is controlled so that fuel gas Gf is supplied to both of the two fuel systems (the first fuel system 14a and the second fuel system 14b) of the gas turbine combustor 1A.

When the operating state satisfies the predetermined operating conditions in this way, in step S102, the first fuel gas Gf1 and the second fuel gas Gf2 are supplied to the first fuel system 14a and the second fuel system 14b, respectively. In this case, the relationship between the heat generation amount C of the fuel gas and the nozzle differential pressure ΔP or the fuel flow rate changes so that the nozzle differential pressure ΔP or the fuel flow rate decreases as the heat generation amount C of the fuel gas Gf increases, as shown by line K1 in FIG. 5. When the heat generation amount C of the fuel gas Gf is relatively small in this way, the nozzle differential pressure ΔP or the fuel flow rate in the supply path of the fuel gas Gf to the combustion chamber 20 increases, making it easier for combustion oscillation to occur. However, by injecting the fuel gas Gf into the combustion chamber 20 from both the first fuel gas nozzle 24a and the second fuel gas nozzle 24b in this way, the flow area of the fuel gas Gf is increased, suppressing the nozzle differential pressure ΔP or the fuel flow rate, and the occurrence of combustion oscillation in the second combustion oscillation generation region B can be suitably avoided.

On the other hand, if the operating state does not satisfy the predetermined operating conditions (step S101: NO), the control unit 104 controls the first flow rate control valve Vr1 so that the first fuel gas Gf1 is supplied from the first fuel gas supply system 10a to the first fuel gas nozzle 24a, and controls the second flow rate control valve Vr2 so that the supply of the second fuel gas Gf2 from the second fuel gas supply system 10b to the second fuel gas nozzle 24b is stopped (step S103). That is, in step S103, as shown in FIG. 6, each valve of the fuel gas supply system 10 is controlled so that fuel gas (first fuel gas Gf1) is supplied only to the first fuel system 14a located radially outward among the two combustion systems of the gas turbine combustor 1A.

When the operating state does not satisfy the predetermined operating condition in this way, in step S103, the first fuel gas Gf1 is supplied only to the first fuel system 14a. In this case, the relationship between the heat generation amount C of the fuel gas and the nozzle differential pressure ΔP or the fuel flow rate is similar to the above-mentioned line K1 in that the nozzle differential pressure ΔP or the fuel flow rate changes to decrease as the heat generation amount C of the fuel gas Gf increases, as shown by line K2 in Fig. 5, but the supply of the second fuel gas Gf2 to the second fuel system 14b is stopped, thereby reducing the flow path area of the fuel gas Gf, and thus shifting to the higher pressure side compared to line K1. When the heat generation amount of the fuel gas Gf is relatively large, the nozzle differential pressure ΔP or the fuel flow velocity in the supply path of the fuel gas Gf to the combustion chamber 20 decreases, making it easier for combustion oscillations to occur in the first combustion oscillation occurrence region. However, by injecting the fuel gas Gf only from the first fuel gas nozzle 24a into the combustion chamber 20 in this manner, the flow path area of the fuel gas Gf is reduced and the nozzle differential pressure is increased, making it possible to preferably avoid the occurrence of combustion oscillations in the zone (first combustion oscillation occurrence region).
In this case, by ejecting fuel gas from the first fuel gas hole 24a which is close to the first air hole 24c, the first fuel gas Gf1 from the first fuel gas hole 24a and the air Ga from the first air hole 24c can be mixed favorably and combusted well.

The threshold Cref, which is defined as an operating condition, is set so that the state indicated by the line K1 where the heat generation amount C is relatively small and the state indicated by the line K2 where the heat generation amount C is relatively large avoid the first combustion oscillation generation region A and the second combustion oscillation generation region B, respectively, and fall within the safe operating region. In other words, by switching between a state in which fuel gas is supplied to both the first fuel system 14a and the second fuel system 14b as shown in FIG. 1 and a state in which fuel gas is supplied only to the first fuel system 14a as shown in FIG. 6 according to the magnitude of the heat generation amount C of the fuel gas relative to the threshold Cref, the first combustion oscillation generation region A and the second combustion oscillation generation region B different from the first combustion oscillation generation region A can be suitably avoided, and the operating state of the gas turbine combustor 1A can be maintained in a stable state in which no combustion oscillation occurs.

In this way, even if the heat value of the fuel gas Gf fluctuates, the gas turbine combustor 1A can be controlled to appropriately avoid combustion oscillations for fuel gas Gf having a wide range of heat values C by selecting to switch between the first fuel system 14a and the second fuel system 14b as the supply destination of the fuel gas Gf based on the heat value C of the fuel gas Gf.

In the above embodiment, the heat generation amount C of the fuel gas Gf is used as the parameter to be determined in step S101, but instead of this, the nozzle differential pressure ΔP, which is another parameter included in the operating state acquired in step S100, may be used. In this case, in step S101, it is determined whether the nozzle differential pressure ΔP is equal to or greater than a threshold value corresponding to the preset nozzle differential pressure ΔP. If the nozzle differential pressure ΔP is equal to or greater than the threshold value (step S101: YES), step S102 is performed to supply the first fuel gas Gf1 and the second fuel gas Gf2 to the first fuel system 14a and the second fuel system 14b, respectively. This increases the flow area of the fuel gas Gf of the fuel gas Gf to suppress the nozzle differential pressure ΔP, and the occurrence of combustion oscillation in the second combustion oscillation generation region B can be suitably avoided. On the other hand, if the nozzle differential pressure ΔP is less than the threshold value (step S100: NO), step S103 is performed to supply the first fuel gas Gf1 only to the first fuel system 14a. This reduces the flow area of the fuel gas Gf and increases the nozzle differential pressure ΔP, making it possible to effectively avoid the occurrence of combustion oscillations in the first combustion oscillation occurrence region A.

In another embodiment, the flow rate of the fuel gas Gf may be used as a parameter included in the operating state. The flow rate of the fuel gas Gf is the flow rate at the discharge position from the nozzle hole. In this case, in step S101, it is determined whether the flow rate of the fuel gas Gf is equal to or greater than a threshold value corresponding to a preset flow rate. If the flow rate of the fuel gas Gf is equal to or greater than the threshold value (step S101: YES), step S102 is performed to supply the first fuel gas Gf1 and the second fuel gas Gf2 to the first fuel system 14a and the second fuel system 14b, respectively. This increases the flow area of the fuel gas Gf of the fuel gas Gf to suppress the nozzle differential pressure, and the occurrence of combustion oscillation in the second combustion oscillation generation region B can be suitably avoided. On the other hand, if the flow rate of the fuel gas G is less than the threshold value (step S101: NO), step S103 is performed to supply the first fuel gas Gf1 only to the first fuel system 14a. This reduces the flow area of the fuel gas Gf and increases the nozzle differential pressure, making it possible to effectively avoid the occurrence of combustion oscillations in the first combustion oscillation occurrence region A.

Second Embodiment
Next, a gas turbine combustor 1B according to the second embodiment will be described. Fig. 7 is an overall configuration diagram of the gas turbine combustor 1B according to the second embodiment, and Fig. 8 is a view illustrating a burner 22 of the gas turbine combustor 1B in Fig. 7, viewed from the axial downstream side.
In the following description, components of the gas turbine combustor 1B corresponding to those of the above-described gas turbine combustor 1A are denoted by common reference numerals, and duplicated descriptions will be omitted as appropriate unless otherwise specified.

The gas turbine combustor 1B further includes a third fuel gas supply system 10c for supplying a third fuel gas Gf3. The third fuel gas Gf3 has a higher calorific value than the aforementioned fuel gas Gf (the first fuel gas Gf1 or the second fuel gas Gf2), and is, for example, liquefied natural gas (LNG: Liquid Natural Gas). The third fuel gas supply system 10c is configured to be able to supply the third fuel gas Gf3 to the third fuel system 14c of the gas turbine combustor 1B from a third fuel gas supply source 33 capable of supplying the third fuel gas Gf3.

In the configuration example shown in FIG. 7, the third fuel gas supply system 10c has a third fuel gas supply line 34 that connects the third fuel gas supply source 33 and the third fuel system 14c, and a third flow rate control valve Vr3 provided on the third fuel gas supply line 34. The opening degree of the third flow rate control valve Vr3 can be controlled based on a control signal from the control device 100, and the flow rate of the third fuel gas Gf3 in the third fuel gas supply line 34 can be adjusted.

The burner 22 includes a third fuel system 14c in addition to the first fuel system 14a and the second fuel system 14b. The third fuel system 14c has a third fuel gas nozzle 24d downstream thereof, and the third fuel gas Gf3 supplied by the third fuel gas supply line 34 of the third fuel gas supply system 10c can be ejected into the combustion chamber 20. The third fuel gas nozzle 24d is disposed radially inward from the second fuel gas nozzle 24b. For example, when starting the gas turbine combustor 1B, the third fuel gas Gf3 is ejected from the third fuel gas nozzle 24d, which effectively improves the ignition performance at the time of starting in the gas turbine combustor 1B that handles fuel gas with a low calorific value.

8, each of the third fuel gas holes 24d is formed by a generally cylindrical tubular member 23e that extends continuously in the circumferential direction (i.e., the third fuel gas hole 24d is formed with the tubular member 23e as an outer cylinder). The third fuel gas hole 24d is provided concentrically with the first fuel gas hole 24a and the second fuel gas hole 24b, and is located radially inward of the second fuel gas hole 24b.
Although not shown in FIG. 8, a swirler may also be provided in the third fuel gas nozzle hole 24d.

7, the burner 22 is provided with a second air nozzle 24e for ejecting air Ga supplied from the air supply system 24 into the combustion chamber 20. Such second air nozzle 24e is provided radially inward from the second fuel gas nozzle 24b and radially outward from the third fuel gas nozzle 24d (in other words, as shown in FIG. 8, the second air nozzle 24e is provided between the second fuel gas nozzle 24b and the third fuel gas nozzle 24d when viewed from the axial direction). The third fuel gas hole 24d, which is provided radially inward from the second fuel gas hole 24b, is distant from the first air hole 24c, which is provided radially outward from the first fuel gas hole 24a, so the third fuel gas Gf3 from the third fuel gas hole 24d is difficult to mix with the air from the first air hole 24c. However, by providing the second air hole 24e between the second fuel gas hole 24b and the third fuel gas hole 24d, the third fuel gas Gf3 from the third fuel gas hole 24d can be well mixed with the air from the second air hole 24e. As a result, for example, when the third fuel gas Gf3 is ejected from the third fuel gas hole 24d at the start of the gas turbine combustor 1B, the third fuel gas Gf3 can be effectively combusted.

8, the second air nozzle 24e is also formed between the cylindrical members 23a and 23e, which are substantially cylindrical and extend continuously in the circumferential direction (i.e., the cylindrical member 23a is an outer cylinder and the cylindrical member 23e is an inner cylinder). As a result, the air Ga ejected from the second air nozzle 24e is mixed with the third fuel gas Gf3 over the entire circumference in the combustion chamber 20. The second air nozzle 24e is formed by a cylindrical member which is continuously formed in the circumferential direction, similar to the first fuel gas nozzle 24a, the second fuel gas nozzle 24b, and the first air nozzle 24c described above.
Although not shown in FIG. 8, a swirler may also be provided in the second air nozzle 24e.

In this embodiment, the first air nozzle 24c and the second air nozzle 24e are configured to receive air from a common air supply source (outside air), but air may be supplied from different air supply sources.

The gas turbine combustor 1B having the above configuration can operate based on a control signal from the control device 100. The control device 100 includes an operating state acquisition unit 102 and a control unit 104, similar to the case where the control target is the gas turbine combustor 1A described above (see FIG. 3), but differs in that the control target of the control unit 104 further includes a third flow control valve Vr3.

Figure 9 is a flowchart showing a method for starting up a gas turbine combustor 1B implemented by the control device 100 of Figure 7, and Figure 10 is a graph showing the behavior of the nozzle differential pressure ΔP versus the load L of a gas turbine started up by the starting method of Figure 9.

First, it is determined whether the gas turbine combustor 1B, which is in a stopped state, has started up (step S200). When the gas turbine combustor 1B starts up (step S200: YES), the operating state acquisition unit 102 acquires the operating state of the gas turbine combustor 1B (step S201). The operating state acquired in step S201 includes the load L of the gas turbine (not shown) driven by the combustion gas generated in the gas turbine combustor 1B.

Then, the control unit 104 controls the third flow rate adjustment valve Vr3 so that the third fuel gas Gf3 is supplied to the third fuel gas nozzle 24d, and controls the first flow rate adjustment valve Vr1 and the second flow rate adjustment valve Vr2 so that the supply of the first fuel gas Gf1 and the second fuel gas Gf2 to the first fuel gas nozzle 24a and the second fuel gas nozzle 24b is stopped (step S202). As a result, in step S202, the third fuel gas Gf3 is supplied to the combustion chamber 20. The third fuel gas Gf3 has a higher heat value than the fuel gas Gf (the first fuel gas Gf1 and the second fuel gas Gf2), so it has good ignition properties and can be combusted well even in the burner 22 immediately after startup.

In this way, in the early stage of startup of the gas turbine combustor 1B (L<L1), the load L of the gas turbine gradually increases while the third fuel gas Gf3 is being supplied to the combustion chamber 20. At this time, as shown in FIG. 10, as the load L of the gas turbine increases, the supply amount of the third fuel gas Gf3 increases, and the nozzle differential pressure ΔP in the third fuel system 14c gradually increases.

Next, the control unit 104 determines whether the load L of the gas turbine is equal to or greater than the first load value L1 (step S203). If the load L is less than the first load value L1 (step S203: NO), the process is returned to step S202, and the load L is increased while only the third fuel gas Gf3 is supplied to the combustion chamber 20. On the other hand, when the load L becomes equal to or greater than the first load value L1 (step S203: YES), the control unit 104 controls the first flow control valve Vr1 so that the first fuel gas Gf1 is supplied to the first fuel gas nozzle 24a (step S204). As a result, in step S204, the supply of the first fuel gas Gf1 to the combustion chamber 20 is started. Although the first fuel gas Gf1 has low ignitability, the first fuel gas Gf1 is mixed with the third fuel gas Gf3, which has good ignitability and was started to be supplied in step S202, and the first fuel gas Gf1 is combusted well together with the third fuel gas Gf3 in the combustion chamber 20. In this way, when the gas turbine load L becomes equal to or greater than the first load value L1, the first fuel gas Gf1 is supplied, and as shown in FIG. 10, the nozzle differential pressure ΔP of the first fuel system 14a gradually increases.

Next, the control unit 104 determines whether the load L of the gas turbine is equal to or greater than the second load value L2 (step S205). If the load L is less than the second load value L2 (step S205: NO), the process returns to step S204. On the other hand, if the load L becomes equal to or greater than the second load value L2 (step S205: YES), the control unit 104 controls the first flow rate control valve Vr1 so that the first fuel gas Gf1 is supplied to the first fuel gas nozzle 24a, and controls the second flow rate control valve Vr2 so that the second fuel gas Gf2 is supplied to the second fuel gas nozzle 24b (step S206). In step S206, the second fuel gas Gf2 is supplied to the combustion chamber 20 in addition to the first fuel gas Gf1, thereby promoting the combustion of the fuel gas Gf with a low heat value in the combustion chamber 20. In this way, when the load L of the gas turbine becomes equal to or greater than the second load value L2, the flow area of the fuel gas increases due to the supply of the second fuel gas Gf2 in addition to the first fuel gas Gf1, and as shown in FIG. 10, the nozzle differential pressure ΔP of the first fuel system 14a shifts to the low pressure side, and the nozzle differential pressure ΔP of the second fuel system 14b gradually increases.

The second load value L2 may be set so that the nozzle differential pressure ΔP of the first fuel system 14a and the second fuel system 14b avoids the first combustion oscillation generation region A and the second combustion oscillation generation region B, respectively, as in the gas turbine combustor 1A described above. In this embodiment, as shown in FIG. 10, when the load L is less than the second load value L2, the first fuel gas Gf1 is supplied to the combustion chamber 20, and the second fuel gas Gf2 is stopped, so that the flow area of the fuel gas Gf is small, and the nozzle differential pressure ΔP of the first fuel system 14a is relatively high. On the other hand, when the load L is equal to or greater than the second load value L2, the first fuel gas Gf1 and the second fuel gas Gf2 are supplied to the combustion chamber 20, so that the flow area of the fuel gas Gf increases, and the nozzle differential pressure ΔP of the first fuel system 14a shifts to the low pressure side, avoiding the second combustion oscillation generation region B and causing the nozzle differential pressure of the second fuel system 14b to rise to avoid the first combustion oscillation generation region A. By setting the second load value L2 in this manner, the gas turbine combustor 1B can be started while the nozzle differential pressure of the first fuel system 14a and the second fuel system 14b avoids the first combustion oscillation generation region A and the second combustion oscillation generation region B, respectively.

In addition, in FIG. 10, the third fuel gas Gf3, which is started to be supplied in step S202, is continuously supplied after the start of the gas turbine combustor 1B, but the supply of the third fuel gas Gf3 may be stopped after the low-heat-value fuel gas Gf can be stably burned in the combustion chamber 20. As described above, the third fuel gas Gf3 is supplied to improve ignition in the combustion chamber 20. When the low-heat-value fuel gas Gf can be burned, the supply of the third fuel gas Gf3 can be stopped to reduce excess consumption of the third fuel gas Gf3.

The control unit 104 may also control the third flow rate control valve Vr3 to stop the supply of the third fuel gas Gf3 when the load L of the gas turbine is equal to or greater than the third load value L3. The third load value L3 is set to be greater than the first load value L1, so that the supply of the third fuel gas Gf3 is stopped at least after the supply of the first fuel gas Gf1 has started for a load L that changes to gradually increase.

In some aspects, the third load value L3 may be set to be greater than the first load value L1 and less than the second load value L2. In this case, the supply of the third fuel gas Gf3 is stopped after the first fuel gas Gf1 is supplied and before the supply of the second fuel gas Gf2 is started. As a result, the supply of the third fuel gas Gf3 is stopped at an early timing after the supply of the first fuel gas Gf1 is started, so that the gas turbine combustor 1B can be started while suppressing the consumption of the third fuel gas Gf3.

In some embodiments, the third load value L3 may be set to be greater than the second load value L2. In this case, the supply of the third fuel gas Gf3 is stopped after the supply of the first fuel gas Gf1 is started and then the supply of the second fuel gas Gf2 is started. As a result, the supply of the third fuel gas Gf3 is stopped after the supply of both the first fuel gas Gf1 and the second fuel gas Gf2 is started, so that the combustion of the fuel gas Gf can be performed more stably and the gas turbine combustor 1B can be started more accurately.

When the first fuel gas Gf1 and the second fuel gas Gf2 are supplied to the combustion chamber 20 in this manner, the control unit 104 transitions to normal operation (step S207), and the start-up control sequence is completed.

As described above, according to each of the above embodiments, when starting up the gas turbine combustor 1B, the first fuel gas Gf1, the second fuel gas Gf2, and the third fuel gas Gf3 are supplied to the combustion chamber 20 in a predetermined order as the load L of the gas turbine increases. This improves ignition performance with the third fuel gas Gf3, which has a high heating value, while favorably combusting the fuel gas with a low heating value, thereby enabling the gas turbine combustor 1B to be started up appropriately.

In addition, the components in the above-described embodiments may be replaced with well-known components as appropriate without departing from the spirit of this disclosure, and the above-described embodiments may be combined as appropriate.

The contents described in each of the above embodiments can be understood, for example, as follows:

(1) A gas turbine combustor according to one aspect includes:
A gas turbine combustor capable of combusting fuel gas and air mixed in a combustion chamber with a burner disposed upstream of the combustion chamber,
The burner is
a first fuel gas nozzle for injecting the fuel gas as a first fuel gas from a first fuel gas supply system connected to a fuel gas supply source for supplying the fuel gas into the combustion chamber;
a second fuel gas nozzle arranged radially inward from the first fuel gas nozzle and configured to inject the fuel gas as a second fuel gas from a second fuel gas supply system connected to the fuel gas supply source into the combustion chamber;
a first air nozzle arranged radially outward from the first fuel gas nozzle and configured to inject the air into the combustion chamber;
Equipped with.

According to the above aspect (1), the first air nozzle for injecting air into the combustion chamber is provided radially outward from the first fuel gas nozzle and the second fuel gas nozzle for injecting fuel gas into the combustion chamber. This allows the air injected from the first air nozzle to be mixed well with the first fuel gas injected from the first fuel gas nozzle radially outward from the second fuel gas nozzle, compared to a case in which the fuel gas and the air nozzle are provided alternately along the circumferential direction. Furthermore, by providing the first air nozzle radially outward from the first fuel gas nozzle and the second fuel gas nozzle, the distance between the first air nozzle and the inner wall of the combustion chamber downstream of the burner is reduced, so that the cooling of the inner wall of the combustion chamber can be promoted by the air injected from the first air nozzle, and the temperature of the inner wall constituting the combustion chamber can be effectively reduced.
The first fuel gas and the second fuel gas are the same fuel gas supplied from a fuel gas supply source via each fuel gas supply system.

(2) In another embodiment, in the above embodiment (1),
The first fuel gas nozzle hole and the second fuel gas nozzle hole are connected to the first fuel gas supply system and the second fuel gas supply system, which are branched off from the common fuel gas supply source, respectively.

According to the above aspect (2), the fuel gas from the common fuel gas supply source is supplied to the first fuel gas nozzle and the second fuel gas nozzle as the first fuel gas and the second fuel gas, respectively, by the first fuel gas supply system and the second fuel gas supply system branching off from the fuel gas supply source.

(3) In another aspect, in the above (1) or (2),
At least one of a flow passage area of the first fuel gas in the first fuel gas supply system and a flow passage area of the second fuel gas in the second fuel gas supply system is adjustable.

According to the above aspect (3), by adjusting the flow path area of the fuel gas in each fuel gas supply system, the nozzle differential pressure of the fuel gas ejected from each fuel gas nozzle hole can be changed, and the occurrence of combustion oscillation can be suitably avoided.

(4) In another aspect, in any one of the above (1) to (3),
The first fuel gas supply system includes:
a first fuel gas branch line branching off from a fuel gas main line connected to the fuel gas supply source;
a first flow rate control valve provided in the first fuel gas branch line;
having
The second fuel gas supply system includes:
a second fuel gas branch line branching off from the fuel gas main line;
a second flow rate control valve provided in the second fuel gas branch line;
having
The opening degree of the first flow rate adjustment valve or the second flow rate adjustment valve can be adjusted independently.

According to the above aspect (4), the opening degree of the flow control valve provided in the line through which the fuel gas flows in each fuel gas supply system is configured to be independently adjustable. This makes it possible to adjust the flow path area of the fuel gas in each fuel gas supply system by adjusting the opening degree of the flow control valve in each fuel gas supply system.

(5) In another embodiment, in the above embodiment (4),
The system is capable of switching between a state in which the openings of the first flow control valve and the second flow control valve are adjusted so as to supply the first fuel gas and the second fuel gas to the first fuel gas hole and the second fuel gas hole, respectively, and a state in which the openings of the first flow control valve and the second flow control valve are adjusted so as to supply the first fuel gas to the first fuel gas hole and stop the supply of the second fuel gas to the second fuel hole.

According to the above aspect (5), by independently adjusting the opening degree of the first flow rate adjustment valve and the second flow rate adjustment valve, it is possible to switch between a state in which the first fuel gas and the second fuel gas are supplied to the first fuel gas nozzle and the second fuel gas nozzle, respectively, and a state in which the first fuel gas is supplied to the first fuel gas nozzle and the supply of the second fuel gas to the second fuel nozzle is stopped.

(6) In another aspect, in any one of the above (1) to (5),
The first air nozzle holes are formed between a plurality of cylindrical members which extend continuously in the circumferential direction.

According to the above aspect (6), the first air nozzle is configured as a space between a plurality of cylindrical members that extend continuously along the circumferential direction. This makes it possible to effectively mix the air ejected from the first air nozzle with the fuel gas ejected from the fuel gas nozzle located radially inward, while avoiding a complicated structure. In particular, by providing the first air nozzle radially outward from the first fuel gas nozzle, the distance between the first air nozzle and the first fuel gas nozzle is shortened, and the air can be effectively mixed with the first fuel gas ejected from the first fuel gas nozzle. In addition, by providing the first air nozzle so as to extend continuously along the circumferential direction, it is possible to cool a wide range of the inner wall that constitutes the combustion chamber with the air ejected from the first air nozzle.

(7) In another embodiment, in the above embodiment (6),
The first air nozzle has a swirler provided along a circumferential direction for swirling the air ejected from the first air nozzle.

According to the above configuration (7), a swirler is provided along the circumferential direction for the first air nozzle formed between a plurality of cylindrical members that extend continuously in the circumferential direction. This allows the air from the first air nozzle to be rectified by the swirler, and allows the air to be mixed favorably with the fuel gas in the downstream combustion chamber, and promotes heat exchange with the inner wall of the combustion chamber, thereby favorably cooling the inner wall that constitutes the combustion chamber.

(8) In another aspect, in any one of the above (1) to (7),
The first fuel gas hole has a larger flow passage area than the second fuel gas hole.

According to the above configuration (8), the flow area of the first fuel gas nozzle provided on the radially outer side is configured to be larger than the flow area of the second fuel gas nozzle provided on the radially inner side. This increases the flow rate of the fuel gas ejected from the first fuel gas nozzle close to the first air nozzle, making it easier to promote mixing with the air ejected from the first air nozzle.

(9) In another aspect, in any one of the above (1) to (8),
The nozzle further includes a third fuel gas hole that is disposed radially inward of the second fuel gas hole and that ejects a third fuel gas having a higher heat value than the fuel gas.

According to the above aspect (9), a third fuel gas nozzle is provided that can eject a third fuel gas having a higher heat value than the fuel gas that can be ejected from the first fuel gas nozzle and the second fuel gas nozzle. The third fuel gas nozzle is disposed radially inward from the second fuel gas nozzle, and for example, when starting up a gas turbine combustor, the third fuel gas is ejected from the third fuel gas nozzle, thereby effectively improving ignition performance at the time of startup in a gas turbine combustor that handles a fuel gas with a low heat value.

(10) In another embodiment, in the above embodiment (9),
The fuel cell further includes a second air nozzle arranged between the second fuel gas nozzle and the third fuel gas nozzle for ejecting the air.

According to the above aspect (10), a second air nozzle for ejecting air is provided between the second fuel gas nozzle and the third fuel gas nozzle. The third fuel gas nozzle provided radially inward from the second fuel gas nozzle is distant from the first air nozzle provided radially outward from the first fuel gas nozzle, so the third fuel gas from the third fuel gas nozzle is difficult to mix with the air from the first air nozzle. However, by providing the second air nozzle between the second fuel gas nozzle and the third fuel gas nozzle, the third fuel gas from the third fuel gas nozzle can be well mixed with the air from the second air nozzle. This allows the third fuel gas to be effectively combusted when ejecting the third fuel gas from the third fuel gas nozzle at the start of a gas turbine combustor, for example.

(11) In another embodiment, in the above embodiment (10),
The second air nozzle holes are formed between a plurality of cylindrical members which extend continuously in the circumferential direction.

According to the above aspect (9), the second air nozzle is configured as a space between a plurality of cylindrical members that extend continuously along the circumferential direction. This makes it possible to effectively mix the air ejected from the second air nozzle with the fuel gas ejected from the third fuel gas nozzle located radially inward, while avoiding a complicated structure.

(12) In another aspect, in any one of the above (1) to (10),
The fuel gas is a low calorie gas.

The above aspect (12) is suitable for a gas turbine combustor that uses, as fuel gas, a low-calorie gas such as blast furnace gas generated during steelmaking in a steelmaking plant.

Reference Signs List 1A, 1B Gas turbine combustor 10 Fuel gas supply system 10a First fuel gas supply system 10b Second fuel gas supply system 10c Third fuel gas supply system 12 Fuel gas supply source 14a First fuel system 14b Second fuel system 14c Third fuel system 16 Fuel gas main line 18a First fuel gas branch line 18b Second fuel gas branch line 20 Combustion chamber 20a Inner wall 22 Burner 24 Air supply system 24a First fuel gas nozzle 24b Second fuel gas nozzle 24c First air nozzle 24d Third fuel gas nozzle 24e Second air nozzle 31a to 31d Swirler 33 Third fuel gas supply source 34 Third fuel gas supply line 100 Control device 102 Operation state acquisition unit 104 Control unit A First combustion oscillation occurrence region B Second combustion oscillation occurrence region Ga Air Gf Fuel gas Gf1 First fuel gas Gf2 Second fuel gas Gf3 Third fuel gas Vr1 First flow rate control valve Vr2 Second flow rate control valve Vr3 Third flow rate control valve

Claims (12)

A gas turbine combustor capable of combusting fuel gas and air mixed in a combustion chamber with a burner disposed upstream of the combustion chamber,
The burner is
a first fuel gas nozzle for injecting the fuel gas as a first fuel gas from a first fuel gas supply system connected to a fuel gas supply source for supplying the fuel gas into the combustion chamber;
a second fuel gas nozzle arranged radially inward from the first fuel gas nozzle and configured to inject the fuel gas as a second fuel gas from a second fuel gas supply system connected to the fuel gas supply source into the combustion chamber;
a first air nozzle arranged radially outward from the first fuel gas nozzle and configured to inject the air into the combustion chamber;
A gas turbine combustor comprising: The gas turbine combustor according to claim 1, wherein the first fuel gas nozzle and the second fuel gas nozzle are connected to the first fuel gas supply system and the second fuel gas supply system, respectively, which are branched off from the common fuel gas supply source. The gas turbine combustor according to claim 1 or 2, wherein at least one of the flow area of the first fuel gas in the first fuel gas supply system and the flow area of the second fuel gas in the second fuel gas supply system is adjustable. The first fuel gas supply system includes:
a first fuel gas branch line branching off from a fuel gas main line connected to the fuel gas supply source;
a first flow rate control valve provided in the first fuel gas branch line;
having
The second fuel gas supply system includes:
a second fuel gas branch line branching off from the fuel gas main line;
a second flow rate control valve provided in the second fuel gas branch line;
having
3. The gas turbine combustor according to claim 1, wherein an opening degree of the first flow rate control valve or an opening degree of the second flow rate control valve is independently adjustable. The gas turbine combustor according to claim 4, which is switchable between a state in which the apertures of the first flow rate control valve and the second flow rate control valve are adjusted so as to supply the first fuel gas and the second fuel gas to the first fuel gas nozzle and the second fuel gas nozzle, respectively, and a state in which the apertures of the first flow rate control valve and the second flow rate control valve are adjusted so as to supply the first fuel gas to the first fuel gas nozzle and stop the supply of the second fuel gas to the second fuel nozzle. The gas turbine combustor according to claim 1 or 2, wherein the first air injection hole is formed between a plurality of cylindrical members that extend continuously in the circumferential direction. The gas turbine combustor according to claim 6, wherein the first air nozzle has a swirler arranged along the circumferential direction for swirling the air ejected from the first air nozzle. The gas turbine combustor according to claim 1 or 2, wherein the first fuel gas nozzle has a flow area larger than that of the second fuel gas nozzle. The gas turbine combustor according to claim 1 or 2, further comprising a third fuel gas nozzle arranged radially inward from the second fuel gas nozzle for ejecting a third fuel gas having a higher heat value than the fuel gas. The gas turbine combustor according to claim 9, further comprising a second air nozzle arranged between the second fuel gas nozzle and the third fuel gas nozzle for ejecting the air. The gas turbine combustor according to claim 10, wherein the second air injection holes are formed between a plurality of cylindrical members that extend continuously in the circumferential direction. The gas turbine combustor according to claim 1 or 2, wherein the fuel gas is a low-calorie gas.

Images