JPH04124522A - Fuel feeding method for combustion device, fuel feeding system, and diffusion fuel nozzle - Google Patents

Abstract

PURPOSE:To sharply reduce NOX concentration and to prevent the occurrence of failure in ignition or unstable combustion in a combustor by a method wherein after a load is increased to a value higher than a set point, for example, 25%, in the middle of a combustion device, a part of fuel is caused to bypass the premixture fuel nozzle side, and a charging fuel flow rate is decreased with the increase in a load. CONSTITUTION:At a 25% or less load being a set point in the middle between a 0% load and during the starting of a gas turbine and a 100% rated load, only a fuel flow rate regulating valve 4 of a diffusion fuel system 2 is opened by a controller 6 for fuel and fuel is charged only through a diffusion fuel nozzle 31. When a total fuel flow rate available when the rated load of a gas turbine is 100% is 100%, operation is effected in a manner that a fuel flow rate F1 is increased from approximate 20% to 40% according to the increase of the load of the gas turbine. After the load of the gas turbine is increased to 25% or more, in addition to the fuel flow rate regulating valve 4 of the diffusion fuel system 2, a fuel flow rate regulating valve 5 of a premixture fuel system 3 and fuel bypass valve 29 of a fuel bypass system 28 are opened by a controller 6 for fuel, and kept at a constant state so that a predetermined set flow rate, for example, 37.5%, can be fed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fuel supply method, a fuel supply system, and a diffusion fuel nozzle for combustion devices such as gas turbines, jet engines, and boilers. , “N○
It's called "S". ) A fuel supply method for a combustion device that can significantly reduce the concentration and is suitable for stabilizing combustion, a fuel supply system for carrying out the method, and a diffusion fuel nozzle used for the method.

[Prior Art] Fig. 5 is a system diagram showing a fuel supply system of a gas turbine commonly used in the past, and Fig. 6 shows a diffusion fuel nozzle used in the fuel supply system shown in Fig. 5 in the radial direction. FIG.

In the conventional fuel supply system shown in FIG.
A diffusion fuel system 2 and a premix fuel system 3 are connected to.

The diffusion fuel system 2 is provided with a fuel flow control valve 4, and the premix fuel system 3 is provided with another fuel flow control valve 5. The fuel flow control valves 4 and 5 are connected to a fuel controller 6.

The diffusion fuel system 2 is connected to the diffusion fuel nozzle 14 of the combustor 7, and the premix fuel nozzle 18 is connected to the premix fuel passage 16 formed in the premix fuel flange 11 of the combustor 7.
It is connected to the.

The combustor 7 includes a first combustor 7 connected on the same center line and forming a pressure chamber. It has a second outer cylinder 8, 9, an end cover 10 attached to the end of the first outer cylinder 8, and a premixed fuel passage 16, and is located between the first and second outer cylinders 8, 9. a premixed fuel flange 11 attached to the first fuel flange 11;
．． Combustor subchamber 1 installed in the center of the second outer cylinders 8 and 9
2, a combustor main chamber 13 disposed on the same center line as this combustor subchamber 12 and installed on the second outer cylinder 9 side;
a diffusion fuel nozzle 14; a front annular air passage 15 formed inside the first outer cylinder 8; A premixed fuel manifold 17 communicated with the premixed fuel passage 16, and a plurality of premixed fuel manifolds 17 arranged at equal intervals in the circumferential direction on the outer peripheral side of the combustor subchamber 12, one end of which is connected to the premixed fuel manifold 17. a premixed fuel nozzle 18 which is connected and whose other end is provided toward the combustor main chamber 13 side;
A premixer is disposed on the outer peripheral side of the end of the combustor subchamber 12, one end is formed so as to surround the outside of the premixed fuel nozzle 18, and the other end is provided facing the combustor main chamber 13. 1
9, a compressed air introduction part 20 connected to the end of the second outer cylinder 9, and a compressed air introduction part 20 connected to the second outer cylinder 9.
A rear annular air passage 21 is formed throughout the inside of the air passage. Note that the combustor subchamber 12 is supported by the first outer cylinder 8 via a support (not shown),
The combustor main chamber 13 is supported by the second outer cylinder 9 via another support (not shown), and the premixer 19 is fixed to the premix fuel flange 11.

The diffusion fuel nozzle 14 is as shown in FIG.

A diffusion fuel flange 22, a sleeve 24 having a diffusion fuel inlet pipe 23 and attached to one side of the diffusion fuel flange 22, and a truncated cone-shaped sleeve 24 having a diffusion fuel nozzle hole 26 in the head. The diffusion fuel flange 22
a chip 25 fixed to the other surface of the chip 25;
The air swirler 27 is provided on the outside of the air swirler. Further, as shown in FIG. 1, this diffusion fuel nozzle 14 is connected to the combustor 7 through the diffusion fuel flange 22.
It is attached to the end cover 10 of.

In the conventional fuel supply system, fuel 200 is supplied from the fuel system 9 line 1, and a set point is set midway between the load 0% at startup of the gas turbine (not shown) and the rated load 100%. For example, when the load is less than 25%, the fuel 10
0 to the diffusion fuel system 2.

The fuel is injected into the combustor sub-chamber 12 from the diffusion fuel nozzle 14 through the fuel flow control valve 4 . On the other hand, air 104 is introduced into the front annular air passage 15, and the air 104 is introduced into the combustor subchamber 1.
The air flows in from an air hole (not shown) provided in 2 and is swirled by an air swirler 27. The diffusion fuel 101 injected from the diffusion fuel nozzle 14 is mixed with the air 104 swirled by the air swirler 27 and combusted in the combustor subchamber 12 to form a diffusion flame (not shown).

Then, after the load on the gas turbine increases to above 25%, about 30% of the total fuel flow is sent to the diffusion fuel nozzle 14.
Approximately 70% of the total fuel flow is supplied to the premix fuel nozzle 18 via the premix fuel system 3 → fuel flow rate control valve 5 → premix fuel passage 16 → premix fuel manifold 17.

Premixed fuel 10 supplied to the premixed fuel nozzle 18
2 is injected into the premixer ]9. On the other hand, the compressed air 1 passes through the rear annular air passage 21 formed across the compressed air introduction part 20 and the second outer cylinder 9 to the premixer 19.
05 will be introduced. Then, the injected premixed fuel 102 and compressed air 105 are premixed in the premixer 19, and the premixed premixed fuel 102 and compressed air 105 are premixed.
The mixture 106 is combusted at the outlet of the premixer 19 using the diffusion flame formed in the subcombustor chamber 12 as a spark.

As the mixture 106 of the premixed fuel 102 and compressed air 105 burns at the outlet of the premixer 19, high temperature and high pressure combustion gas (not shown) is generated in the combustor main chamber 13,
The combustion gas is introduced into a gas turbine, where the thermal energy of the combustion gas is converted into mechanical energy, which rotates the gas turbine and performs work.

In addition, as a technology related to fuel supply for this type of gas turbine, there is another technology described in Japanese Patent Application Laid-Open No. 1-139919.

[Problems to be Solved by the Invention] In the prior art, if fuel is supplied only from the diffusion fuel nozzle 14 and combusted after the load on the gas turbine increases to 25% or more, as shown in FIG. As shown by the broken line and indicated by the symbol A, as the load on the gas turbine increases, the NOx concentration increases.

On the other hand, after the load on the gas turbine increases to 25% or more, if fuel is supplied from both the diffusion fuel nozzle 14 and the premix fuel nozzle 18 and is combusted,
As shown by the solid line in the figure and indicated by the symbol B, the NOx concentration decreases.

However, in the conventional technology, the diffused fuel flow rate from the point when the gas turbine load exceeds 25% is approximately 30% of the total fuel flow rate.
%, and there is a limit to reducing NOx. In addition, after the load of the gas turbine increases to the above 25% or more,
Experiments using test equipment and actual equipment have shown that lowering the ratio of the diffusion fuel flow rate to the total fuel flow rate and increasing the ratio of the premixed fuel flow rate to the total fuel flow rate can further promote lower NOx. Proven. For example, when the load increases to 25% or more, the ratio of the diffusion fuel flow rate to the total fuel flow rate is set to 5% at the rated load.

It has been found that if the ratio of the premixed fuel flow rate to the total fuel flow rate is 95% at the rated load, the NOx concentration can be significantly reduced.

However, at the load of 25%, the ratio of the diffusion fuel flow rate to the total fuel flow rate needs to be about 40%, and it is necessary to adjust the diffusion fuel flow rate within the range from about 40% to the 5%. The diffusion fuel flow rate is expressed as the total fuel flow rate.
When adjusted in the range of 5 to 40%, the pressure difference between the inside and outside of the diffusion fuel nozzle 4 becomes significantly large.

The fuel flow rate Q and the fuel differential pressure ΔP have the following relationship.

Q Town r lower...(])Also,
The fuel differential pressure ΔP has the following relationship with the average value ΔP of the fuel differential pressure and the fluctuation amount ΔP2 of the fuel differential pressure.

ΔP=Δp, ±ΔP2 (2) When the fuel differential pressure ΔP is small from equations (1) and (2) above.

According to the relationship with the fuel flow rate Q, it can be seen that if the average value ΔP1 of the fuel differential pressure is small and the variation ΔP2 is large, there is a possibility that the Q level will be 0.

Furthermore, since the air supplied to the combustor subchamber 12 contains vortices, the pressure within the combustor subchamber 12 always has a minute vibration component.

Even if the fuel flow rate of the diffusion fuel 101 changes slightly. may become 0, resulting in misfires and unstable combustion.

The first object of the present invention is to be able to significantly reduce the NOx concentration during operation after the load has increased to, for example, 25% or more, which is a set point set from the start of the combustion equipment to the rated load. It is an object of the present invention to provide a fuel supply method for a combustion device that can prevent misfire or unstable combustion within a combustor.

A second object of the present invention is to provide a fuel supply system for a combustion device that can accurately implement the fuel supply method described above.

A third object of the present invention is to provide a diffusion fuel nozzle for a combustion device that can be incorporated into the fuel supply system and function effectively.

[Means for solving the problem] The first objective is to reduce the total flow rate of fuel from the diffusion fuel nozzle to the combustor below the set point on the way from 0% load at startup of the combustion device to 100% rated load. After the load rises above the set point, fuel is supplied to the diffusion fuel nozzle at a predetermined set flow rate that is equal to or higher than the combustion stability limit value, and part of the fuel supplied to the diffusion fuel nozzle is bypassing the part to the premixed fuel nozzle side, and reducing the fuel flow rate input from the diffusion fuel nozzle to the combustor in response to an increase in the load of the combustion device, and after the load increases above the set point. is achieved by injecting a fuel flow rate corresponding to the load into the combustor from the premix fuel nozzle, combining the premix fuel directly supplied to the premix fuel nozzle and the fuel bypassed from the diffusion fuel nozzle. be done.

The second purpose is to transfer a portion of the diffused fuel from the diffused fuel nozzle to the premixed fuel system when the load rises above a set point on the way from 0% load at startup to 100% rated load. This is achieved by providing a fuel bypass system that bypasses the

Furthermore, the second purpose is to transmit the total diffusion from the diffusion fuel nozzle to the premixed fuel system via the fuel bypass system when the load of the combustion device exceeds the set point, in response to the increase in load. This can be achieved even better by increasing the ratio of the bypass fuel flow to the fuel flow.

The third object is to provide concentrically an outer sleeve to which a substantially truncated conical outer tip is attached and an inner sleeve to which a substantially truncated conical inner tip is attached, and to provide a space between the outer sleeve and the inner sleeve. forms an annular passage for diffusion fuel, a cylindrical passage for fuel bypass is formed inside the inner sleeve, and a plurality of diffusion fuel nozzle holes are provided at equal intervals in the circumferential direction in the outer tip. , the inner chip is provided with a plurality of fuel bypass holes at equal intervals in the circumferential direction, the annular passage for the diffusion fuel is connected to the diffusion fuel system, and the cylindrical passage for the fuel bypass is connected to the fuel bypass hole. This is achieved by contacting the system.

[Function] In the invention according to claim 1 of the present invention, the diffusion fuel nozzle The entire flow of fuel is injected into the combustor.

Then, after the load increases to 25% or more, fuel is supplied to the diffusion fuel nozzle at a predetermined set flow rate that is equal to or higher than the combustion stability limit value. That is, a fuel flow rate equivalent to 1, for example, 30% of the total fuel flow rate of 100% when the rated load of the combustion device is 100% is always supplied to the diffusion fuel nozzle.

Furthermore, after the load on the combustion device increases to 25% or more, fuel is also supplied to the premixed fuel nozzle.

At this time, the fuel flow rate supplied to the premixed fuel nozzle is increased in response to the increase in the load on the combustion device.

After the load on the combustion device increases to 25% or more, a portion of the fuel is bypassed from the diffusion fuel nozzle to the premixed fuel nozzle. At this time.

The fuel flow rate bypassed from the diffusion fuel nozzle to the premixed fuel nozzle side is increased in response to the increase in the load on the combustion device, while the fuel flow rate injected from the diffusion fuel nozzle into the combustor is increased in response to the increase in the load on the combustion device. When the rated load of the combustion device is 100%, the fuel flow actually injected into the combustor from the diffusion fuel nozzle is reduced to, for example, 5% of the total fuel flow. As a result, a fuel flow rate that is the sum of the fuel flow rate directly supplied to the premix fuel nozzle and the fuel flow rate bypassed from the diffusion fuel nozzle is input from the premix fuel nozzle to the combustor. As the load increases, the amount of fuel that is bypassed from the diffusion fuel nozzle to the premixed fuel nozzle increases, and the amount of fuel that is directly supplied to the premixed fuel nozzle also increases, so that the flow rate from the molecularly mixed fuel nozzle to the combustor increases. The input fuel flow rate increases.

As described above, in the invention according to claim 1 of the present invention, after the load increases to 25% or more, which is a set point halfway from the load 0% of the combustion device to 100% rated load, the diffusion fuel nozzle is A portion of the supplied fuel is bypassed to the premix fuel nozzle, and the fuel flow rate is actually injected into the combustor from the diffusion fuel nozzle.

Since the reduction is made in response to an increase in the load on the combustion device, NOx can be significantly reduced.

Furthermore, after the load on the combustion device rises above the set point, fuel is always supplied to the diffusion fuel nozzle at a set flow rate that is above the combustion stability limit value.
As can be seen from the relationship in equations 1) and (2), it is possible to increase the fuel pressure difference between the inside and outside of the diffusion fuel nozzle, so that the combustion that causes the ignition from the diffusion fuel nozzle to the combustor can be made large. It becomes possible to input the necessary fuel flow rate. Therefore, misfires and unstable combustion can be reliably prevented even when the combustion device is operated after the load has increased above the set point.

Next, in a second aspect of the present invention, a fuel bypass system is provided for bypassing a portion of the diffusion fuel from the diffusion fuel nozzle to the premix fuel system.

Then, the combustion equipment changes from 0% load at startup to 10% rated load.
For example, 25%, which is a set point set on the way to 0%.
After the load increases above, a portion of the fuel supplied to the diffusion fuel nozzle is bypassed to the premix fuel system through the fuel binos system.

Therefore, after the load of the combustion device increases above the set point, the fuel flow rate that is directly supplied to the premix fuel system from the premix fuel system and the fuel flow that is bypassed from the fuel bypass system is changed from the premix fuel system to the premix fuel nozzle. The premixed fuel is supplied together with the fuel flow rate and is injected into the combustor from the premixed fuel nozzle.

Therefore, in the invention according to claim 2 of the present invention, the method of the present invention can be carried out accurately.

Furthermore, in the invention according to claim 3 of the present invention, when the load of the combustion device rises above the set point from the diffusion fuel nozzle to the premixed fuel system via the fuel bypass system, the load is adjusted to correspond to the load. In this way, the ratio of the bypass fuel flow rate to the total diffusion fuel flow rate is increased.

As a result, in the invention according to claim 3 of the present invention, the method of the present invention can be carried out even more accurately.

According to the fourth aspect of the present invention, an outer sleeve to which seven substantially truncated conical tips are attached and an inner sleeve to which a substantially truncated inner tip is attached are provided concentrically.

An annular passage for diffusion fuel is formed between the outer sleeve and the inner sleeve. A cylindrical passage for fuel bypass is formed inside the inner sleeve.

A plurality of diffusion fuel nozzle holes are provided in the outer tip at equal intervals in the circumferential direction. A plurality of fuel bypass holes are provided in the inner chip at equal intervals in the circumferential direction. The annular passage for diffusion fuel is connected to a diffusion fuel system, while the cylindrical passage for fuel bypass is connected to a fuel bypass system.

Thereby, the diffusion fuel supplied to the annular passage formed between the outer sleeve and the inner sleeve is injected into the combustor through each diffusion fuel nozzle hole provided in the outer tip.

Furthermore, when the load on the combustion device rises above the set point, communication between the fuel bypass system connected to the diffusion fuel nozzle and the premix fuel system is opened.

When the fuel bypass system and the premix fuel system are opened, a portion of the diffused fuel enters the cylindrical passage formed inside the inner sleeve through each fuel bypass hole provided in the inner chip, and enters the cylindrical passage. from there to the fuel bypass system, and from the fuel bypass system to the premix fuel system.

Therefore, in the invention according to claim 4 of the present invention, by incorporating it into a fuel supply system and using it.

When the load of the combustion device is below the set point, the entire fuel flow supplied to the diffusion fuel system is input into the combustor through the annular passage → the diffusion fuel nozzle hole, and when the load of the combustion device rises above the set point, A part of the fuel flow rate supplied to the diffusion fuel system can be bypassed to the premixed fuel system through the fuel bypass hole → cylindrical passage → fuel bypass system.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a fuel supply system for carrying out the fuel supply method according to the present invention, and FIG. 2 is a system diagram of the fuel supply system applied to a gas turbine as a combustion device. 1 is an enlarged sectional view of the diffusion fuel nozzle taken along a radial section, showing an embodiment of the diffusion fuel nozzle of the present invention that uses gas as fuel.

In the fuel supply system of the embodiment shown in FIG. 1, the same parts as in the fuel supply system shown in FIG. 5 are designated by the same reference numerals, and further explanation thereof will be omitted.

Incidentally, the fuel supply system shown in FIG. 1 is provided with a diffusion fuel nozzle 31 that can bypass a portion of the diffusion fuel.

A fuel bypass system 28 is connected to the diffusion fuel nozzle 31 . This fuel bypass system 11f28.

Premixed fuel system #! It is connected to the downstream side of a check valve 30' provided downstream of the fuel flow rate control valve 5 in No. 3.

The fuel bypass system 28 also includes a fuel bypass valve 2.
9 and a check valve 30 are provided.

The fuel bypass valve 29 is connected to the fuel controller 6.

As shown in an enlarged view in FIG. 2, the diffusion fuel nozzle 31 includes a diffusion fuel introduction pipe 32, an outer sleeve 33, an inner sleeve 34, a fuel flange 35, and a seven-outlet tip 36 having a substantially truncated conical shape. Similarly, the inner tip 37 has a substantially truncated conical shape and a fuel bypass outlet pipe 46.

A diffusion fuel system M2 is connected to the diffusion fuel introduction pipe 32.

The outer sleeve 33 and the inner sleeve 34 are assembled concentrically, and an annular passage 38 for diffused fuel is formed between the outer sleeve 33 and the inner sleeve 34. Further, the outer sleeve 33 and the inner sleeve 34 are welded to one surface of the fuel flange 35.

The fuel flange 35 is provided with a diffusion fuel hole 39 and a fuel bypass hole 44 . A plurality of the diffusion fuel holes 39 are provided near the outer circumferential side of the fuel flange 35 at equal intervals in the circumferential direction.

A plurality of the fuel bypass holes 44 are provided inside the diffusion fuel hole 39 at equal intervals in the circumferential direction.

The outer tip 36 and the inner tip 37 are arranged around the same center line, and a conical annular passage 40 for diffused fuel is formed between the outer tip 36 and the inner tip 37. Further, the outer tip 36 and the inner tip 37 are welded to the other surface of the fuel flange 35.

A plurality of diffusion fuel nozzle holes 41 are provided at the head of the outer tip 36 at equal intervals in the circumferential direction.

A plurality of fuel bypass holes 42 are provided at the head of the inner tip 37 at equal intervals in the circumferential direction.

Further, a conical passage 43 for fuel bypass is formed inside the inner chip 37.

A cylindrical passage 45 for fuel bypass is formed inside the inner sleeve 34 .

The fuel bypass outlet pipe 46 is connected to the fuel bypass system 28.

An air swirler 4 is provided on the outside of the head of the outer tip 36.
7 is provided.

FIG. 3 is a diagram showing the distribution of gas turbine load and fuel flow rate in the present invention.

Next, an example of the fuel supply method of the present invention will be explained with reference to FIGS. 1, 2, and 3 in relation to the operation of the fuel supply system and the diffusion fuel nozzle in this embodiment.

First, a set point, for example 2
At a load of less than 5%, the fuel controller 6 opens only the fuel flow control valve 4 of the diffusion fuel system 2, and closes the fuel control valve 5 of the premix fuel system 3 and the fuel bypass valve 29 of the fuel bypass system 28. Further, the opening degree of the fuel flow rate control valve 4 of the diffusion fuel system 2 is as shown in FIG.
When the total fuel flow rate is 100% when the rated load of the gas turbine is 100%, the fuel controller 6 adjusts the flow rate from about 20% to 4% in response to the increase in the gas turbine load.
Adjust to supply 0% fuel flow.

Here, when the fuel 100 flows from the fuel system 1, all of the fuel 100 flows to the diffusion fuel system 2, and the diffusion fuel 100 flows into the diffusion fuel system 2.
1 flows from the diffusion fuel system 2 to the diffusion fuel nozzle 31.

The diffusion fuel 101 that has flowed into the diffusion fuel nozzle 31 flows through the diffusion fuel introduction pipe 32 → annular passage 38 → diffusion fuel passage 39 → conical annular passage 40 → each diffusion fuel nozzle hole 4 as shown in FIG.
1, and from the diffusion fuel nozzle hole 41 to the diffusion fuel nozzle 3
The air 1 is injected to the outside 48 of the air 1 by the air swirler 47
04 and is introduced into the combustor subchamber 12 shown in FIG. 1, where it is combusted.

Therefore, when the load of the gas turbine is from 0% to less than the set point, for example, 25%, as can be seen from FIG. The total fuel flow rate of 1
00%, the fuel flow rate Fl is increased from about 20% to 40% in response to an increase in the load of the gas turbine.

Next, after the load on the gas turbine increases to 25% or more, the fuel controller 6 controls the diffusion fuel system 2.
In addition to the fuel flow control valve 4 of the premix fuel system 3, the fuel flow control valve 5 of the premix fuel system 3 and the fuel bypass valve 2 of the fuel bypass system 28
Open 9. The opening degree of the fuel flow rate control valve 4 of the diffusion fuel system 2 is set to a predetermined set flow rate, for example, 37.5%, when the total fuel flow rate at 100% rated load of the gas turbine is 100%. It shall be kept constant so that it can be supplied. The opening degree of the fuel flow control valve 5 of the premixed fuel system 3 is as follows:
When the total fuel flow rate when the gas turbine's rated load is 100% is 100%, the fuel flow rate is adjusted so that, for example, 20% to 95% of the fuel flow rate can be supplied in response to an increase in the gas turbine load. The opening degree of the fuel bypass valve 29 of the fuel bypass system 28 is determined based on the rated load of the gas turbine 100.
When the total fuel flow rate is 100%, the fuel flow rate is adjusted so that, for example, 17.5% to 32.5% of the fuel flow rate can be bypassed in response to an increase in the load of the gas turbine.

Therefore, when fuel 100 is supplied from the fuel system 1 shown in FIG. 1, the fuel 100 is branched into a diffusion fuel system 2 and a premix fuel system 3.

The diffusion fuel 101, which is the fuel branched into the diffusion fuel system 11E2, flows to the diffusion fuel nozzle 31 as described above, and the diffusion fuel introduction pipe 32→annular passage 38→diffusion shown in FIG. 2 of the diffusion fuel nozzle 31 The fuel flows from the fuel passage 39 to the conical annular passage 40 to each diffusion fuel nozzle hole 41.

A portion of the fuel is injected into the outside 48 of the diffusion fuel nozzle 31 through each diffusion fuel nozzle hole 41 . As mentioned above, the fuel flow rate control valve 4 of the diffusion fuel system 2 is a constant valve that can supply a fuel flow rate of 1, for example, 37.5% when the total fuel flow rate at 100% rated load of the gas turbine is 100%. Therefore, the diffusion fuel nozzle 31 is always injected with a fuel flow rate of 37.5%.

In this state, as described above, the fuel bypass valve 29 is open. Therefore, a portion of the diffusion fuel 101 that has flowed to the conical annular passage 40 of the diffusion fuel nozzle 31 shown in FIG. 2 is injected to the outside of the diffusion fuel nozzle 31 from each diffusion fuel nozzle hole 41, as described above.

The remainder flows into the conical passage 43 from each fuel bypass hole 42 . The bypass fuel 103, which is the fuel that has flowed into the conical passage 43, flows through the fuel bypass passage 44 → the cylindrical passage 4.
5 → Fuel bypass system @2 via fuel bypass outlet pipe 46
8 and enters the premix fuel system lA3 from this fuel bypass system 28. As described above, when the total fuel flow rate is 100% when the rated load of the gas turbine is 100%, the fuel 1<I pass valve 29 is adjusted to 17.5%, for example, in response to an increase in the load of the gas turbine. from 32.5%
As a result, as can be seen from FIG. 3, the F1 bypass, which is the fuel flow rate of the bypass fuel 103 from the diffusion fuel nozzle 31 to the fuel bypass system 28, increases to 17.5 in response to the increase in the load of the gas turbine. 5% to 32.5%
increases to On the other hand, the fuel flow rate F1 of the diffusion fuel 101 injected from the diffusion fuel nozzle 31 to the outside 48 decreases from 20% to 5% in response to the increase in the load of the gas turbine.

On the other hand, the premixed fuel 102, which is the fuel branched to the premixed fuel system 3, flows through the fuel bypass system 28→fuel bypass valve 29→check valve 30 to the connection part of the fuel bypass system 28. And the fuel bypass system 28
The premixed fuel 102 and the fuel bus fuel 103 join together at the connection point, and are sent to the premixed fuel nozzle 18 shown in FIG. The air is premixed with compressed air 105 in the combustor 19, and then introduced into the combustor main chamber 13 where it is combusted.

Therefore, when the load on the gas turbine increases to 25% or more, as can be seen from FIG. F1 which is the fuel flow rate
The combined fuel flow rate with the bypass is input. In addition, when the load on the gas turbine increases to 25% or more,
As mentioned above, when the total fuel flow rate is 100% when the rated load of the gas turbine is 100%, the fuel bypass valve 29 is set to 1, for example, in response to an increase in the load of the gas turbine.
The opening degree is adjusted so that 7.5% to 32.5% of the fuel flow rate can be bypassed, and the fuel flow rate control valve 5 of the premix fuel system 11E3 can supply a fuel flow rate of 20% to 95%, for example. Since the opening is adjusted, at 100% rated load of the gas turbine, as can be seen from FIG. Approximately 62.5% of the total fuel flow is directly supplied, approximately 35% of the fuel flow is bypassed from the diffusion fuel nozzle 31 to the fuel bypass system 928, and approximately 32.5% of the bypassed fuel flow is supplied to the premixed fuel flow. This is combined with approximately 62.5% of the fuel flow supplied directly to the fuel system 3. Therefore, from the premixed fuel nozzle 18 to the combustor 7
Approximately 95% of the fuel flow rate will be injected.

In this way, when the load on the gas turbine increases to 25% or more, the flow rate of fuel injected from the diffusion fuel nozzle 31 into the combustor 7 is significantly reduced in response to the increase in the load on the gas turbine. Therefore, it is possible to significantly reduce the NOX concentration.

Moreover, when the load of the gas turbine increases to the set point, for example, 25% or more, the diffusion fuel nozzle 31 is Since a fuel flow rate of, for example, 37.5% of the set fuel flow rate is always supplied, the minimum necessary fuel flow rate can be injected from the diffusion fuel nozzle 31 into the combustion I17. Therefore, the fuel pressure difference, which is the pressure difference between the conical annular passage 40 inside the diffusion fuel nozzle 31 shown in FIG. 2 and the outside 48 of the diffusion fuel nozzle 31, can be increased.
As can be seen from the relationship in equation (2), it is possible to avoid the influence of fluctuations in fuel differential pressure and reliably prevent misfires and unstable combustion.

In addition, in one or more of the explanations, various numerical values are not limited to the above-mentioned numerical values, and are appropriately set depending on the model.

Next, FIG. 4 shows an embodiment of the diffusion fuel nozzle of the present invention suitable for using oil as the fuel, and is an enlarged sectional view of the main part taken along a radial cutting plane.

The diffusion fuel nozzle 50 shown in FIG. 4 includes an outer sleeve 51, an inner sleeve 52 concentrically arranged and fixed inside the outer sleeve 51, and a distal end portion between the outer sleeve 51 and the inner sleeve 52. swivel 55
It is composed of:

A pair of shoulders 53 and 54 are formed on the distal end sides of the outer sleeve 51 and the inner sleeve 52.

The swivel 55 is incorporated and supported between the shoulders 53 and 54.

Between the outer sleeve 51 and the inner sleeve 52,
A hollow cylindrical passage 56 for diffusion fuel is formed. This hollow cylindrical passage 56 communicates with the upstream side of the swirler 55 . Further, the hollow cylindrical passage 56 is connected to a diffusion fuel system (not shown).

A funnel-shaped spin chamber 5 having a smaller diameter than the outer diameter of the hollow cylindrical passage 56 is provided on the wire end side of the outer sleeve 51.
7 is formed. This spin chamber 57 communicates with the downstream side of the swirler 55 . Further, a diffusion combustion nozzle hole 58 is formed at the tip of the outer sleeve 51 so as to communicate with the tip of the spin chamber 57 .

A frusto-conical fuel bypass hole 59 is provided at the tip of the inner sleeve 52 . This fuel bypass hole 59 communicates with the spin chamber 57 .

A cylindrical fuel bypass passage 60 is formed inside the inner sleeve 52 . One end of this fuel bypass passage 60 communicates with the fuel bypass hole 59, and the other end is connected to a fuel bypass system (not shown).

The fuel bypass system is provided with a fuel bypass valve (not shown), and the fuel bypass system is connected to a premix fuel system (also not shown).

Even in the fuel supply system using the diffusion fuel nozzle 50 of the embodiment shown in FIG. 4, only the fuel flow control valve provided in the diffusion fuel system is opened when the load on the gas turbine is less than the set point. The fuel flow control valve provided in the premix fuel system and the fuel bypass valve provided in the fuel bypass system are closed.

Here, the diffusion fuel 107 supplied from the diffusion fuel system flows into the hollow cylindrical passage 56 of the diffusion fuel nozzle 50, is swirled by the swirler 55, is sent to the spin chamber 57, and is passed through the diffusion fuel nozzle hole 58 into the combustor. (not shown). Note that in this state, as described above.

Since the fuel bypass valve is closed, all of the diffusion fuel 107 sent to the diffusion fuel nozzle 50 is injected into the combustor through the diffusion fuel nozzle hole 58.

Then, when the load on the gas turbine increases above the set point, in addition to the fuel flow control valve installed in the diffusion fuel system, the fuel flow control valve installed in the premix fuel system and the fuel bypass system are activated. The closed fuel bypass valve is also opened.

Then, the diffusion fuel 107 sent from the diffusion fuel system to the diffusion fuel nozzle 5o is transferred to the hollow cylindrical passage 56 as described above.
→The fuel is sent to the spin chamber 57, a part of which is introduced into the combustor through the diffusion fuel nozzle hole 58, and the remainder is bypassed into the fuel bypass passage 60 through the fuel bypass hole 59. The bypass fuel 108 then flows from the fuel bypass passage 60 to the fuel bypass system, enters the premixed fuel system from the fuel bypass system, joins the premixed fuel supplied directly to the premixed fuel system, and flows through the premixed fuel nozzle. (not shown), the premixed fuel and bypass fuel are together fed into the combustor.

Regarding other effects of the embodiment shown in FIG.

This is similar to the embodiment shown in FIGS. 1 and 2 above.

Note that the present invention is applicable not only to gas turbines but also to combustion devices such as jet engines and boilers.

[Effects of the Invention] According to the invention described in claim 1 of the present invention described above, when the load is below the set point on the way from 0% load at startup of the gas turbine to 100% rated load, the flow from the diffusion fuel nozzle to the combustor After the fuel has risen above the set point, the fuel is supplied to the diffusion fuel nozzle at a predetermined set flow rate that is equal to or higher than the combustion stability limit value, and the fuel is supplied to the diffusion fuel nozzle. A portion of the fuel is bypassed to the premix fuel nozzle side, and the fuel flow rate input from the diffusion fuel nozzle to the combustor is reduced in response to an increase in the load of the combustion device, so that the load increases above the set point. Then, from the premixed fuel nozzle to the combustor, the premixed fuel directly supplied to the premixed fuel nozzle and the fuel bypassed from the diffusion fuel nozzle are combined, and a fuel flow rate corresponding to the load is injected. After the load increases to 25% or more, which is a set point halfway between the rated load of the combustion device from 0% to 100%, a portion of the fuel supplied to the diffusion fuel nozzle is converted to premixed fuel. Since the fuel is bypassed to the nozzle side and the flow rate of fuel actually injected into the combustor from the diffusion fuel nozzle is reduced in response to the increase in load on the combustion device, it has the effect of significantly reducing NOx concentration. , and after the load on the combustion device rises above the set point,
Since fuel is always supplied to the diffusion fuel nozzle at a set flow rate that is equal to or higher than the combustion stability limit value, the above (1) is satisfied.
, As can be seen from the relationship in equation (2), it is possible to increase the fuel pressure difference between the inside and outside of the diffusion fuel nozzle, which has the effect of reliably preventing misfires and unstable combustion. be.

Further, according to the second aspect of the present invention, when the load increases from 0% of the load at startup of the combustion device to a set point on the way from 100% of the rated load, the premixed fuel is discharged from the diffusion fuel nozzle. Since a fuel bypass system is provided for bypassing a portion of the diffused fuel to the fuel system, there is an effect that the method of the present invention can be carried out accurately.

Furthermore, according to the invention according to claim 3 of the present invention.

From the diffusion fuel nozzle to the premixed fuel system via the fuel bypass system, when the load of the combustion device increases above the set point, the bypass fuel flow rate is increased relative to the total diffusion fuel flow rate in response to the increase in load. Since the ratio is increased, there is an effect that the method of the present invention can be carried out more accurately.

According to the invention according to claim 4 of the present invention.

An outer sleeve to which a substantially truncated conical outer tip is attached and an inner sleeve to which a substantially truncated conical inner tip is attached are provided concentrically, and an annular passage for diffusion fuel is provided between the outer sleeve and the inner sleeve. form,
A cylindrical passage for fuel bypass is formed inside the inner sleeve, a plurality of diffusion fuel nozzle holes are provided in the outer tip at equal intervals in the circumferential direction, and a plurality of diffusion fuel nozzle holes are provided in the inner tip at equal intervals in the circumferential direction. A plurality of fuel bypass holes are provided at intervals, and the annular passage for diffusion fuel is connected to the diffusion fuel system, and the cylindrical passage for fuel bypass is connected to the fuel bypass system, so that the fuel supply system When the load on the combustion device is below the set point.

The entire fuel flow rate supplied to the diffusion fuel system is injected into the combustor through the annular passage → the diffusion fuel nozzle hole, and when the load of the combustion device rises above the set point, the fuel flow rate supplied to the diffusion fuel system is reduced. There is an effect that a part of the fuel can be bypassed to the premixed fuel system side via the fuel bypass hole → cylindrical passage → fuel bypass system.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a fuel supply system for carrying out the fuel supply method according to the present invention. FIG. 2, a system diagram of a fuel supply system applied to a gas turbine as a combustion device, shows an embodiment of the diffusion fuel nozzle of the present invention, which targets gas as fuel. FIG. 3 is an enlarged sectional view taken along a cutting plane, and a line diagram showing the load and fuel flow distribution of the gas turbine in the present invention. Fig. 4 shows an embodiment of the diffusion fuel nozzle of the present invention suitable for oil as a fuel, and is an enlarged sectional view of the main part taken along a radial cutting plane, Fig. 5 is a system diagram showing the prior art, and Fig. 6 is a system diagram showing the prior art. The figure is an enlarged sectional view of the diffusion fuel nozzle used in the prior art taken along a radial cutting plane, No. 71! ! i is a diagram showing the relationship between the load on the gas turbine and the concentration of NOx generated during fuel combustion. DESCRIPTION OF SYMBOLS 1... Fuel system, 2... Diffusion fuel system, 3... Premix fuel system, 4, 5... Fuel flow control valve, 6... Fuel controller, 7... Combustor, 12 ... Combustor subchamber, 13... Combustor main chamber, 15... Front annular air passage, 16... Premix fuel passage, 17... Premix fuel manifold, 18... Premix Fuel nozzle, 19.
...Premixer, 20...Compressed air introduction section, 21...
Rear annular air passage, 28...Fuel bypass system, 29
... Fuel bypass valve, 31 ... Diffusion fuel nozzle, 3
2... Diffusion fuel introduction pipe, 33... Outer sleeve,
34... Inner sleeve, 35... Fuel flange,
36...Outer tip, 37...Inner tip, 3
8... Annular passage for diffusion fuel, 39... Diffusion fuel hole, 40... Conical annular passage, 41... Diffusion fuel nozzle hole, 42... Fuel bypass hole, 43... Fuel Conical passage for bypass, 44...Fuel bypass hole, 4
5... Cylindrical passage, 46... Fuel bypass outlet pipe,
47... Air swirler, 50... Diffusion fuel nozzle, 5
1... Outer sleeve, 52... Inner sleeve, 5
5... Fuel swirler, 56... Hollow cylindrical passage for diffusion fuel, 57... Spin chamber, 58... Diffusion fuel nozzle hole, 59... Fuel bypass hole, 60... Fuel bypass passage, 100...Fuel (gas) + 10
1... Diffusion fuel, 102... Premixed fuel. 103... Bypass fuel, 104... Air, 105
···Compressed air. 106.--Mixture of premixed fuel and compressed air, 107.
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Claims (1)

[Claims] 1. From 0% load to 100% rated load when starting the combustion device
When the load is below the set point on the way to , the full flow of fuel is injected from the diffusion fuel nozzle to the combustor, and after the load rises above the set point, the fuel is injected into the diffusion fuel nozzle at a rate above the combustion stability limit value and at a predetermined rate. A predetermined set flow rate is supplied, a part of the fuel supplied to this diffusion fuel nozzle is bypassed to the premixed fuel nozzle side, and the fuel flow rate input from the diffusion fuel nozzle to the combustor is controlled by the load of the combustion device. When the load increases above the set point, the premixed fuel is supplied directly to the premixed fuel nozzle and the premixed fuel is bypassed from the diffusion fuel nozzle. A method for supplying fuel to a combustion device, characterized by supplying fuel at a flow rate corresponding to the load. 2. Supply diffusion fuel from the diffusion fuel system to the diffusion fuel nozzle, inject this diffusion fuel into the combustor and cause diffusion combustion, supply premixed fuel from the premixed fuel system to the premixed fuel nozzle, and perform the premixed fuel nozzle. In a fuel supply system for a combustion device that injects fuel into a combustor for premix combustion, when the load rises above a set point on the way from 0% load at startup of the combustion device to 100% rated load, the diffusion 1. A fuel supply system for a combustion device, comprising a fuel bypass system that bypasses a portion of diffused fuel from a fuel nozzle to a premixed fuel system. 3. From the diffusion fuel nozzle to the premixed fuel system via the fuel bypass system, when the load of the combustion device exceeds the set point, the bypass fuel flow rate is increased relative to the total diffusion fuel flow rate in response to the increase in load. 3. The fuel supply system for a combustion device according to claim 2, wherein the fuel supply system is configured to increase the ratio of . 4. An outer sleeve to which a substantially truncated conical outer tip is attached and an inner sleeve to which a substantially truncated conical inner tip is attached are provided concentrically, and an annular for diffusion fuel is provided between the outer sleeve and the inner sleeve. a cylindrical passage for fuel bypass is formed inside the inner sleeve; a plurality of diffusion fuel nozzle holes are provided at equal intervals in the circumferential direction on the outer tip; A plurality of fuel bypass holes are provided at equal intervals in the circumferential direction, and the annular passage for the diffusion fuel is connected to the diffusion fuel system, and the cylindrical passage for the fuel bypass is connected to the fuel bypass system. The combustion device features a diffusion fuel nozzle.