JP4106098B2 - Operation method of combustion chamber of gas turbine and combustion chamber of gas turbine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention, with a mixed burner before fuel is supplied, an operation method of a combustion chamber of a gas turbine, the premixing burner, the fuel flow direction is arranged opposite laterally offset from each other Formed from at least two hollow partial cones such that the cross section of the hollow chamber formed by these hollow partial cones increases in the fuel flow direction, and the respective central axes of said partial cones are offset from each other; Adjacent partial cone walls form tangential slits or passages for the flow of combustion air into the inner chamber formed by the partial cone, and the combustion chamber is connected to the main burner. The invention relates to a method driven by at least one premixing burner having a function and at least one premixing burner having the function of an ignition burner, as well as a combustion chamber of a gas turbine .
[0002]
[Prior art]
According to EP-B1-0321809, a double-conical premixing burner is known, which premixing burner consists of two partial cones with central axes offset from each other. Tangential air inflow slits are formed on both sides of the burner, and in this air inflow slit, gaseous fuel supplied in the radial direction or liquid fuel supplied in the axial direction arrives from the compressor. Mixed with burned air. When a so-called vortex breakdown of this fuel-air mixture with a very high peripheral velocity occurs, an optimal and uniform fuel concentration is produced in the region of the burner mouth. By shifting the partial cones radially relative to each other, the size of the air inlet slit formed between them and thus the peripheral speed of the fuel-air mixture can be changed, so that the vortex is always constant depending on the use conditions. Optimum conditions for the occurrence of decay can be obtained.
[0003]
As is known from the EP-A1-0387532 patent, a plurality of double conical burners of this kind are arranged on the countercurrent side of the combustion chamber of the gas turbine. In that case, these double-cone burners function as ignition burners or main burners depending on the amount of combustion air flowing through them. Both types of burners are arranged in a row and alternately in the combustion chamber. This allows a relatively small ignition burner to be operated with ideal mixing within the full load range, thus allowing relatively little NOx diffusion even at partial loads.
[0004]
From the viewpoint of environmental protection, it has become a challenge to significantly reduce NOx diffusion, but this is not possible with known combustion chambers. A disadvantage of this type of combustion chamber is the relatively large pressure loss in the double cone burner. This is a cause of a large fuel demand and a reduction in output and thus a reduction in gas turbine efficiency.
[0005]
[Problems to be solved by the invention]
In order to eliminate all of the above disadvantages, the object of the present invention is to improve the method and apparatus for operation of the combustion chamber so as to obtain improved turbine efficiency and reduced NOx diffusion. It is in.
[0006]
[Means for Solving the Problems]
According to this object the present invention a method which solves the main burner is driven only as a mixer for the preparation of fuel-air mixture is ignited by the main burners ignition burner, the main burner by driving the main burner A flame front is formed in the outflow area, and the flame front of this main burner is always stabilized by the flame front of the ignition burner during operation of the combustion chamber, and the swirl number of the combustion air introduced into the main burner The main burner and the ignition burner are loaded with combustion air having different swirl numbers so that the swirl number of the combustion air introduced into the burner is kept lower, and the swirl number of the combustion air of the ignition burner is greater than 0.7. I tried to make it bigger.
Further, according to the combustion chamber of the gas turbine that solves the above-mentioned problem, the ratio of the inflow portion cross section in the air inflow slit to the outflow portion cross section of the end portion of the main burner is larger than the corresponding ratio in the ignition burner. I did it.
[0007]
Since it is known that the limit for the occurrence of vortex breakdown is at a swirl number of 0.7, combustion air is introduced into the main burner with a swirl number lower than this limit value and ignition is performed with a swirl number higher than this limit value. It is introduced to the burner. Therefore, the main burner cannot be ignited without an ignition burner in full load operation or partial load operation. On the other hand, the main burner in the conventionally known method is not extinguished in full load operation, but is operated so dilute that partial ignition is not ignited unless it is supported by an ignition burner.
[0008]
The required reduction of the main burner swirl number is advantageously achieved by the fact that the ratio of the air inlet slit to the main burner outlet cross section is made larger than the corresponding ratio in the ignition burner. For this purpose, the inflow slit of the main burner is enlarged or its outflow cross section is reduced. The same objective is achieved by reducing the opening angle of the main burner.
[0009]
According to the advantageous solution of the invention, the pressure loss can be reduced by enlarging the inlet slit of the main burner. This increases the power and efficiency of the turbine.
[0010]
By disposing the main burner and the ignition burner at intervals in at least two rows, the combustion chamber can be ignited satisfactorily and its operation is ensured, and the temperature distribution at partial load is only one row. More effective than burner. By arranging double conical burners of the same structure in each row, a good lateral ignition of the ignition burner is ensured. On the other hand, when each row of double cone burners has a main burner and an ignition burner alternately, good ignitability of the main burner and a uniform temperature distribution in the radial direction in the combustion chamber Is possible.
[0011]
It is particularly advantageous if the main burner is operated at a load that does not produce NOx and the flame temperature of the ignition burner is increased until it guarantees the stability of the combustion chamber in all operating conditions.
[0012]
According to another embodiment of the invention, the combustion chamber is formed as an annular combustion chamber, the double conical burners are arranged in three rows and are circular in a common vertical plane in a known manner. Is arranged. In this case, one row of ignition burners is arranged between two rows of main burners. This arrangement achieves a particularly effective ratio of ignition burner to main burner, which further reduces NOx diffusion due to the relatively small number of ignition burners. If both rows of the main burner are arranged in common or separately connected or disconnected, the radial temperature distribution can be controlled as expected, so that the turbine is The load can be increased accordingly.
[0013]
Increasing the flame temperature of the ignition burner can improve the fire extinguishing behavior of the combustion chamber without significantly increasing NOx diffusion.
[0014]
Next, a plurality of embodiments of the present invention are shown in the drawings, and a silo combustion chamber or an annular combustion chamber and respective burners will be described below.
[0015]
【Example】
In the silo combustion chamber 1 of the gas turbine, a plurality of double conical burners are arranged in a circle in a common plane as the ignition burner 2 or the main burner 3. In that case, one row of ignition burners 2 is arranged successively from one row to the other inside one row of main burners 3 (see FIG. 1).
[0016]
The ignition burner 2 formed as a conventional double-cone burner consists of two half-divided hollow partial cones 4, 5, which are located laterally offset from each other. (See FIG. 2). Correspondingly, the central axes 6, 7 of the partial cones 4, 5 are likewise laterally offset and positioned side by side (see FIG. 4). In this way, one tangential air inflow slit 8, 9 is formed on both sides of the ignition burner 2 in a mirror-symmetric manner. The combustion air 10 flows into the inner chamber of the ignition burner 2 through these air inflow slits 8 and 9, in other words, into the conical hollow chamber 11 (see FIG. 2).
[0017]
Both partial cones 4, 5 each have one cylindrical starting end 12, 13, which is arranged offset from each other and facing each other like the partial cones 4, 5. ing. Thus, the tangential air inlet slits 8 and 9 are formed over the entire length of the ignition burner 2 on the counterflow side. A nozzle 14 is arranged at the cylindrical start ends 12, 13, and its fuel injection 15 takes place at the narrowest cross section of the conical hollow chamber 11 formed by the two partial cones 14, 15. Is called. Of course, the ignition burner 2 can also be formed in a purely conical shape, i.e. without the cylindrical start ends 12,13.
[0018]
Both partial cones 4, 5 are provided with one fuel conduit 16, 17 at the outer end of the tangential air inlet slit 8, 9, respectively. These fuel conduits 16, 17 are provided with openings 18 through which gaseous fuel 19 reaches the conical hollow chamber 11 of the ignition burner 2. The gaseous fuel 19 is then mixed with the combustion air 10 flowing in through the tangential air inlet slits 8, 9. This mixing takes place in the region of the tangential air inlet slits 8,9. Both partial cones 4, 5 have a flat opening angle 20. The ignition burner 2 is provided with a collar-like closing plate 22 which serves to fix the partial cones 4 and 5 on the combustion chamber side 21.
[0019]
The liquid fuel 23 flowing through the nozzle 14 is injected into the conical hollow chamber 11 at an acute angle, so that a fuel spray that is as uniform as possible is prepared in the plane of the outlet cross section 24 of the ignition burner 2. Is done. This conical liquid fuel profile 25 is surrounded by combustion air 10 which flows in a tangential direction and rotates, ie, swirls. The concentration of the liquid fuel 23 is diluted by the combustion air 10 that is sequentially mixed in the axial direction. A uniform optimum combustion concentration across the cross section is obtained in the region of vortex breakdown, in other words in the region of the backflow zone 26. Ignition is performed at the tip of the backflow zone 26. Only at this point is a stable flame front 27 produced.
[0020]
When the gaseous fuel 19 burns, it is mixed with the combustion air at the outer ends of the tangential air inlet slits 8 and 9, resulting in a fuel-air mixture 28 being similarly formed at that location. .
[0021]
The main burner 3 is likewise provided with a conventional double-cone burner, whose partial cones 4 ′ and 5 ′ are arranged so as to be opposed to each other with a significant deviation compared to the ignition burner 2. ing. As a result, the central axes 6 ′ and 7 ′ thereof have a larger mutual distance in the lateral direction than that of the central axes 6 and 7 of the ignition burner 2 (see FIGS. 4 and 5). As a result, the gap width of the air inlet slits 8 ', 9' of the main burner 3 in the tangential direction is increased, and therefore the swirl number of the combustion air 10 'is reduced. In this way, the occurrence of vortex breakdown is eliminated, in other words, the main burner 3 acts only as a mixer, does not ignite itself and does not form a stable flame front.
[0022]
In the silo combustion chamber 1 of the gas turbine, the combustion air 10 ′ is introduced into the main burner 3 with a low swirl number, or the combustion air 10 is introduced into the ignition burner 2 with a high swirl number. Thereby, the stable flame front 27 already demonstrated about the ignition burner 2 can be formed. The fuel / air mixture 25 ′, 28 ′ of the main burner 3 is ignited by the adjacent ignition burner 2. The flame front 27 'of the main burner 3 is always stabilized by the flame front 27 of the ignition burner 2 during the operation of the silo combustion chamber 1 (see FIGS. 1 to 3).
[0023]
In the second embodiment, the combustion chamber of the gas turbine is formed as an annular combustion chamber and comprises two rows of double-cone burners that are circular in a common vertical plane. Is arranged. Each row comprises only double cone cone burners of the same structure, in which case the rows of ignition burners 2 are arranged on the outside and the rows of main burners 3 are arranged on the inside (see FIG. 6). Both burner rows may be arranged in the reverse order. Furthermore, it is also possible to arrange the ignition burner 2 as well as the main burner 3 in each row of double-cone burners, in which case these burners are arranged alternately and adjacent to each other in the row. Are spaced (see FIG. 7).
[0024]
In yet another embodiment, the annular combustion chamber 29 of the gas turbine comprises three rows of double-cone burners arranged in a circle in a common vertical plane, in which case a row of ignition burners 2 Are arranged between two rows of main burners 3 (see FIG. 8).
[0025]
【The invention's effect】
The advantage of the present invention is, in particular, that the NOx diffusion that has conventionally been generated by the main burner can be almost completely avoided. However, in order to realize such combustion with almost no generation of NOx, the residence time of the fuel-air mixture in the main burner must be relatively short. Therefore, the swirl number of the combustion air entering the main burner is reduced to the extent that vortex breakdown can no longer occur. This makes the main burner unstable and only acts as a mixer.
[Brief description of the drawings]
FIG. 1 is a schematic illustration of an embodiment in which a gas turbine silo combustion chamber is provided with various double conical burners.
FIG. 2 is a partially broken perspective view of an ignition burner formed as a double cone burner.
FIG. 3 is a partially broken perspective view of a main burner formed as a double conical burner.
4 is a schematic cross-sectional view taken along the line IV-IV in FIG. 2;
5 is a schematic cross-sectional view taken along the line VV in FIG. 3. FIG.
FIG. 6 is a partial schematic view of an embodiment with various double conical burners in the annular combustion chamber of a gas turbine.
FIG. 7 is a schematic view similar to FIG. 6 of another embodiment.
FIG. 8 is a schematic view similar to FIG. 6 of another embodiment.
[Explanation of symbols]
1 silo combustion chamber, 2 ignition burner, 3 main burner, 4, 4'5, 5 'partial cone, 6, 6', 7, 7 'central axis, 8, 8', 9, 9 'air inlet slit, 10, 10 'combustion air, 11 conical hollow chamber, 12, 13 starting end, 14 nozzle, 15 fuel injection, 16, 17 fuel conduit, 18 opening, 19, 19' gaseous fuel, 20, 20 'opening Angle, 21 Combustion chamber, 22 Closure plate, 23 Liquid fuel, 24, 24 'Outflow cross section, 25, 25' Liquid fuel profile, 26 Backflow zone, 27, 27 'Flame front, 28, 28' Fuel air mixture 29 Annular combustion chamber

Claims (13)

A method of operating a combustion chamber of a gas turbine comprising a premix burner to which fuel is supplied, wherein the premix burner is at least two hollow, arranged opposite each other in the fuel flow direction. Adjacent partial cones are formed from partial cones such that the cross-section of the hollow chamber formed by these hollow partial cones increases in the fuel flow direction and the respective central axes of the partial cones are shifted from each other. The body wall portion forms a tangential slit or passage for flowing combustion air into the inner chamber formed by the partial cone, and the combustion chamber has at least one function as a main burner. In a method driven by two premixing burners and at least one premixing burner having the function of an ignition burner,
By driving the main burner (3) only as a mixer for the preparation of the fuel-air mixture (25 ', 28'), igniting the main burner with the ignition burner (2) and driving the main burner (3) A flame front (27 ') is formed in the region of the outflow part of the main burner, and the flame front (27') of the main burner is always used during the operation of the combustion chamber (1, 29). 27) so that the swirl number of the combustion air (10 ') introduced into the main burner (3) is kept lower than the swirl number of the combustion air introduced into the ignition burner (2). In addition, the main burner (3) and the ignition burner (2) are loaded with combustion air (10 ') having different swirl numbers, and the swirl number of the combustion air (10) of the ignition burner (2) is made larger than 0.7. Gaster characterized by The method for driving the emission of the combustion chamber.   Most of the fuel used for the operation of the combustion chamber, consisting of gaseous and / or liquid fuel, is combusted through the main burner (3), and the flame temperature of the ignition burner (2) is reduced to the combustion chamber ( The method of claim 1, wherein the method is raised until stability of 1,29) is assured.   3. The method according to claim 2, wherein the combustion chamber is driven by a main burner (3) and an ignition burner (2) arranged in at least two rows adjacent to each other.   A row of ignition burners (2) is driven by two rows of main burners (3) adjacent to this row of ignition burners (2), and both rows of the main burners (3) are shared or separated The method according to claim 1, wherein the method is connected or disconnected.   2. The method according to claim 1, wherein the main burner (3) is operated with a combustion air charge which is less than half that of the ignition burner (2). Fuel with a mixing burner before it is supplied to a combustion chamber of a gas turbine, the premixing burner, the at least two hollow conical sectional bodies which are arranged opposite offset laterally from one another in the fuel flow direction The cross section of the hollow chamber formed by these hollow partial cones is increased in the fuel flow direction, and the central axes of said partial cones are offset from each other so that adjacent partial cones The body wall forms a tangential slit or passage for the flow of combustion air into the inner chamber formed by the partial cone, the combustion chamber having at least one function as a main burner In a type comprising two premix burners and at least one premix burner having the function of an ignition burner,
The main burner (3) is driven only as a mixer for the preparation of the fuel-air mixture (25 ', 28'), the main burner is ignited by the ignition burner (2), and the main burner (3) By driving, a flame front (27 ') is formed in the region of the outflow of the main burner, and the flame front (27') of this main burner is always ignited during operation of the combustion chamber (1, 29). The number of swirls of the combustion air (10 ′) introduced into the main burner (3) is more than the number of swirls of the combustion air introduced into the ignition burner (2). The ratio of the inflow section cross section in the air inflow slit (8 ', 9') to the outflow section cross section (24 ') at the end of the main burner (3) is set so that the ignition burner (2 corresponding magnitude than the ratio Kuna' in) Characterized in that there, the combustion chamber of a gas turbine.   The combustion chamber according to claim 6, wherein the air inflow slits (8 ', 9') of the main burner (3) are formed to be enlarged with respect to the air inflow slit of the ignition burner (2).   7. Combustion chamber according to claim 6, wherein the outflow section cross section (24 ') of the main burner (3) is reduced relative to the outflow cross section of the ignition burner (2).   The opening angle (20 ′) of the main burner (3) formed by increasing the cross section of the hollow chamber in the fuel flow direction is made smaller than the opening angle (20) of the ignition burner (2). The combustion chamber according to claim 6.   The combustion chamber according to any one of claims 6 to 9, wherein the main burner (3) and the ignition burner (2) are arranged at intervals in at least two rows.   11. Combustion chamber according to claim 10, wherein a structurally identical main burner (3) or ignition burner (2) is arranged in each row.   The combustion chamber according to claim 10, wherein the main burners (3) and the ignition burners (2) are alternately arranged in one row.   The combustion chamber according to any one of claims 6 to 12, wherein the combustion chamber is an annular combustion chamber (29).

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