JP4317628B2 - Oil nozzle purge method for gas turbine combustor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an oil nozzle purge method for a gas turbine combustor, which cuts off oil fuel and gas fuel.ChangeThis is a purge method that is applied to a dual type combustor that can be combusted in order to prevent coking from occurring after the fuel is switched from oil to gas and causing coking and clogging of the nozzle.
[0002]
[Prior art]
  In dual-type gas turbine combustors, fuel is cut from oil to gas.ChangeAfter that, the gas operation is performed, but the fuel is used.gasCut intoChangeAfter that, the gas fuel burns and remains in a high temperature state with the fuel oil remaining, so that the residual oil is coked and the nozzle is blocked by this. So fuel cut to gas burningChangeLater, the remaining oil must be purged in an appropriate manner.
[0003]
FIG. 7 is a cross-sectional view showing a nozzle portion in the dual-type gas turbine combustor described above. In the figure, the outline is described. A pilot nozzle 40 is disposed at the center of a nozzle of a combustor, and eight main nozzles 30 are disposed around the nozzle, as will be described later. The pilot nozzle 40 is supplied with either pilot oil fuel 41 or pilot gas fuel 42 from the rear end, and the pilot oil fuel 41 passes through the central pipe 43 and is supplied from the injection port of the nozzle tip 44 to the oil. The fuel 45 is injected. The pilot gas fuel 42 passes through the periphery of the pipe 43 and is injected as gas fuel 46 from an injection port around the tip, and any of these fuels is ignited to form a pilot flame.
[0004]
  On the other hand, in the main nozzle 30, the oil fuel supplied from the oil supply system flows into the central pipe 32 from the oil distribution flow path 31 and is injected as oil fuel 34 from the outlet of the nozzle tip 33, from the gas supply system. The supplied gas fuel is a gas reservoir.39, Passes through the periphery of the central tube 32, and is ejected from a peripheral injection port immediately after the nozzle tip 33.
[0005]
  FIG. 8 is a front view of the combustor nozzle. As shown in the figure, a pilot nozzle 40 is disposed at the center of the combustor 50, and eight main nozzles 30 are disposed around it. Turn offChangeCan be burned. Of the main nozzles, the hatched nozzles in the figure are the main A nozzles, and the ones without the hatched lines are the main B nozzles, and A and B are alternately arranged. In this way, the nozzle is composed of three systems, ie, a main A system, a main B system, and a pilot system, and fuel is supplied from separate systems.
[0006]
FIG. 9 is a cross-sectional view showing the tip portion of the main nozzle 30 described in FIG. 7. The tip 33 is an oil reservoir 38, and a plurality of injection ports 37 are formed around the wall where the oil reservoir 38 is formed. Inclined. The injection port 37 communicates with an oil reservoir 38 and the oil fuel 34 is injected.
[0007]
The dual-type nozzle of the gas turbine combustor described above has a pilot nozzle 40 at the center as shown in FIGS. 7 and 8, and the pilot nozzle 40 is surrounded by eight main nozzles 30. Since the surroundings are hot, the remaining oil is less likely to coking than the main nozzle 30 and the main nozzle 30 is more likely to be clogged by coking of oil. Therefore, it is necessary to purge (push out) oil remaining after the fuel is switched to gas burning.
[0008]
  FIG. 10 is a diagram showing a conventional oil fuel system and purge method of a gas turbine. In the figure, reference numeral 60 denotes a gas turbine, and a plurality (20) of combustors 50 are arranged around the gas turbine. As shown in FIG. 8, each combustor 50 has a total of eight pilot nozzles 40 at the center and a main nozzle A30 and a main nozzle B30 arranged alternately. As shown in FIG. 10, in the pilot system, the main A system, and the main B system, oil fuel is supplied from different oil fuel systems. The pilot nozzle (P) is from the pilot system 20, the main nozzle (A) is from the main A system 21, and the main nozzle (B) is the main B system.22To each of the 20 combustors 50. Further, in the main A system 21, fuel is equally supplied to each combustor 50 by the distributor 23, and in the main B system 22, fuel is supplied to each combustor by the header 24.
[0009]
  In the fuel supply system described above, an air tank 29 for storing air compressed by the compressor is provided, and the pipe 25P and the control valve 26, the pipe 25A and the control valve 27, the pipe 25B and the control valve 28 are connected from the air tank 29. Are connected to the pilot system 20, the main A system 21, and the main B system 22, respectively. In such a system, immediately after the fuel is switched to gas burning, the valves 26, 27, 28 are opened, and the pressurized air from the air tank 29 is supplied to the pilot system 20, the main A system 21, and the main B system 22 respectively. Inject the oil remaining in the piping system to the nozzle for a period of time, and the fuel nozzle30The oil remaining in the pipe and nozzle is discharged.
[0010]
The portions where coking is likely to occur due to the remaining oil are the oil distribution flow path 31 shown in FIG. 7 and the oil sump 38 and the injection port 37 shown in FIG. 9, and the oil remains in these places and is operated by gas burning. If this is continued, the oil will cause coking, solidify in the nozzle, and when the oil fuel is used again, the inside and the tip of the nozzle will be blocked, so the oil is sufficiently purged as described above. There is a need.
[0011]
[Problems to be solved by the invention]
  As described above, in the conventional oil nozzle purge method in the gas turbine combustor, the fuel is switched from oil to gas.ChangeIf the gas fuel is burned with the fuel oil remaining immediately after it is obtained, it is placed in a high temperature state, and the oil in the nozzle is caulked and solidified to close the nozzle. For this purpose, the fuel is switched from oil to gas.ChangeImmediately after feeding, the remaining oil is purged and discharged by sending air. If this purge is insufficient, the oil will not be discharged sufficiently and coking will occur, and if the purge is performed excessively, a large amount of oil fuel will be pushed out in a short time, causing the gas turbine to undergo a sudden output change. This is not preferable.
[0012]
  Therefore, in the present invention, in a dual type gas turbine combustor, fuel is switched from oil to gas.ChangeImmediately after cleaning, a nozzle purge that sends water and air to the nozzle section with appropriate pressure and timing, and pushes out a large amount of oil in a short time during the purge to discharge the residual oil so as not to cause fluctuations in the output of the gas turbine. An object is to provide a method.
[0013]
[Means for Solving the Problems]
The present invention provides the following methods (1) to (8) in order to solve the above-mentioned problems.
[0014]
  (1) In an oil nozzle of a gas turbine combustor that can be used by switching between oil and gas fuel and the fuel supply system has three systems of main A, main B, and pilot, the fuel is switched from oil to gas.ChangeImmediately after the operation, water or gas is passed through each of the main A, main B, and pilot systems in a time-sharing manner for a predetermined time, and finally, the oil remaining in each system is purged by simultaneously passing the gas for a predetermined time. Oil turbine purge method for gas turbine combustor.
[0015]
  (2) The use of water or gas in the time division is as follows: first, water in the main B system, then gas in the main A system, then gas in the main B system, then gas in the pilot system, and finally 3 The purge method according to (1), wherein the purge is performed simultaneously with gas in the system.
(3) The purge method according to (1), wherein the purge is performed only with gas.
[0016]
  (4) The last gas purge is characterized in that it is higher in pressure and shorter in time than the pressure of the previous gas purge (1)From(3)EitherThe described purge method.
[0017]
  (5) The last gas purge is performed with a time lag instead of simultaneously passing in each of the three systems (1)From(3)EitherThe described purge method.
[0018]
  (6) The gas purge in the pilot system is lower than the gas purge pressure in the main A and main B systems (1)From(3)EitherThe described purge method.
[0020]
(7) The purge method according to any one of (1) to (6), wherein the gas is air.
[0021]
(8) The oil nozzle of the gas turbine combustor which can be used by switching between oil and gas fuel and the fuel supply system has three systems of main A, main B and pilot, and the water purge is in both the main A and B systems An oil nozzle purging method for a gas turbine combustor, characterized in that the gas turbine combustor is mixed with the fuel oil before the fuel is switched from the oil to the gas at the same time, and is continued for a predetermined time after the fuel switching, and thereafter the gas purge is performed in a time-sharing manner.
[0022]
  The gas turbine combustor oil nozzle purge method of the present invention is based on (1) as a basic method, and the fuel is switched from oil to gas.ChangeIf the gas is burned, the oil remaining in the oil nozzle system will coke and be fixed and the nozzle will be blocked, so it must be purged. In (1) of the present invention, the main A, main B, and pilot systems are purged by flowing water or gas in a time-sharing manner, and finally the remaining oil is purged with gas simultaneously for the three systems. Purge all residual oil. In (1) of the present invention, the three systems are purged separately and at different timings, so that a large amount of residual oil is not pushed out to the combustor in a short period of time, which causes fluctuations in the output of the gas turbine. There is nothing. In addition, since the three systems are purged with gas at the same time, the residual oil can be completely pushed out.
[0023]
  In (2) of the present invention, the main B system where coking is most likely to occur is first purged with water. Next, the main A system, the main B system, and then the pilot system are purged at different timings in a time-sharing manner, so that the residual oil in the main B system, which is most likely to cause coking, can be reliably purged.Further, in the invention of (3), since the purging is performed only with the gas without using water, the purging can be easily performed with only the gas easily even when there is no water supply facility.
[0024]
  (4), The pressure of the last gas purge is higher than the pressure of the gas purge performed before, and the time is shortened, and the oil remaining at the end is pushed out instantaneously.5In the invention of (3), the last purge is also carried out so that the time is shifted in each of the three systems so that the remaining oil flows out smoothly and continuously, not simultaneously, so that there is no fluctuation in the output of the gas turbine due to the purge. To do.
[0025]
  or(6In the invention of), since coking is relatively difficult to occur in the pilot system, the gas purge pressure can be lowered to reduce the amount of gas used.. FurtherIn the invention of (7), since the gas uses air, it is not necessary to use other expensive gas, and there is no need for gas recovery, etc., and purging can be easily performed only with air equipment. it can.
[0026]
  In (8) of the present invention, BurningEven after the charge switching is completed, the water purge is continued, so that oil remains and is not exposed to high temperatures. Also, water purge is fuel switchingTimeIn this case, the remaining oil is reduced, and the oil is not pushed out and the load is not suddenly changed.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a system diagram of an apparatus for carrying out an oil nozzle purging method for a gas turbine combustor according to the present invention, and is a system diagram for implementing the first to fifth embodiments of the present invention. In the figure, the basic system is shown in the figure.10However, the features of the present invention are the portions indicated by reference numerals 1 to 5 and 10, and other configurations are shown in the figure.10Is the same as These characteristic parts will be described in detail below.
[0028]
  In FIG. 1, 1 is a water tank, 2 and 3 are piping, and 4 and 5 are control valves. A pipe 2 from the water tank 1 is connected to each pipe (20 pipes) of the main A system 21 through a control valve 4. The control valve 4 is provided in each of 20 pipes. Piping2 isOil after branching by distributor 23 is distributedMain A system 2120 eachOn the tubeEach is connected. Similarly, the pipe 3 is connected to each pipe branched by the header 24 of the main B system 22 via the control valve 5.
[0029]
The control valves 4 and 5 are provided in each of the 20 pipes, and the opening degree can be adjusted so as to be a predetermined pressure as will be described later, and the pipes supply water from the water tank 1 by opening and closing at a predetermined time. The opening / closing and pressure setting are controlled by the control device 10.
[0030]
  As shown in FIG. 1, the dual type oil fuel nozzle is composed of three systems of a pilot system 20, a main A system 21, and a main B system 22.10However, as described above, due to the difference in the structure and arrangement of the nozzles, in the main A system 21, there are considerable differences in the mounting positions of the 20 combustors, for example, a difference of 4 m, and oil fuel is supplied to these fuel nozzles. Distributors 23 are provided to distribute evenly, and fuel oil is also supplied to the main B system 22 via the header 24. Water from the water tank 1 is supplied to the distributors 23, Each of the 20 pipes distributed by the header 24 flows into the pipe. Further, due to the difference in structure and system, coking that occurs due to residual oil tends to occur in the order of the main B system, the main A system, and the pilot system.
[0031]
FIG. 2 is a timing diagram of purging of the oil nozzle purging method for the gas turbine combustor according to the first embodiment of the present invention, which is carried out in the system shown in FIG. As shown in the figure, when purging, the main A, main B, and pilot systems are purged separately to suppress the output fluctuation of the gas turbine, and the purge method is also performed at different timings to reduce the output fluctuation. First, a low-pressure purge is performed, and then a high-pressure purge is performed.
[0032]
In FIG. 2, first, in the main B system where coking is most likely to occur, 5 seconds after the end of fuel switching (t₀= 5 seconds), water purge W (B) is performed. The water purge W (B) is performed by opening the control valve 5 shown in FIG. 1 with a predetermined opening, and the flow rate is 6 t / hour and the time is t₁= 60 seconds. Then t₂= After 5 seconds, air purge LP (A) is performed with low-pressure air in the main A system. The air purge LP (A) has a low pressure of +0.7 bar and the time is t_Three= 112 seconds.
[0033]
Then t_Four= 5 seconds later, this time, air purge LP (B) with low-pressure air is performed in the main B system. The time of the air purge LP (B) is t_Five= 90 seconds, the pressure is the cabin pressure + 0.7 bar. Then t₆= After 5 seconds, air purge LP (P) with low-pressure air is performed in the pilot system. The time of this air purge LP (P) is t₇= 315 seconds, the pressure is the cabin pressure +0.3 bar. In the pilot system, since caulking is relatively difficult, 0.3 bar is set. When the air purge LP (P) of this pilot system is finished, finally t₈= After 5 seconds, air purge HP (A), HP (B), HP (P) is performed with high-pressure air at the same time for each of the main A, main B, and pilot systems. The time at this time is t₉= 30 seconds, and the pressure in the passenger compartment is +1.3 bar.
[0034]
As described above, in each system, the remaining oil is not purged at once in a short time, but the air purge is divided into the purge with the low-pressure air in the previous stage and the purge with the high-pressure air in the subsequent stage. When purging at the same time, a large amount of oil fuel is discharged, which burns in a short period of time and causes fluctuations in the output of the gas turbine. Further, since coking is most likely to occur in the main B system, the water purge W (B) is performed first, then the air purge and finally the high pressure air purge.
[0035]
The purge pressure must be controlled so that the difference between the supply pressure of the purge air and the pressure in the vehicle interior is constant. As described above, based on the vehicle interior pressure, +0.7 bar for low pressure, Set to +1.3 bar. In addition, since the purge operation time of the valve is about 0.5 seconds, for example, in the air purge LP (A) in the main A system, the valve operation time t₂, T_FourT₂+ T_Three+ T_FourIs the actual opening time, and the actual opening time when the air flows out is t_ThreeIt will be.
[0036]
According to the first embodiment, the main A, main B, and pilot systems are purged at different timings, respectively. In the main A system, the low-pressure air purge LP (A), and then High pressure air purge HP (A) in the main B system, water purge W (B) first, then low pressure air purge LP (B), and finally high pressure air purge HP (B). In the pilot system, low pressure air purge LP (P) is performed, and then high pressure high air purge HP (P) is performed. In addition, the last air purge HP (A), HP (B), HP (P) is performed at a high pressure at the same time in a short time, and all remaining oil is discharged. Even if the fuel is switched from oil to gas by such a purging method, there is almost no remaining oil in the oil nozzle system, so that coking does not occur and the nozzle is not clogged. Therefore, the output fluctuation of the gas turbine does not occur. Note that the air purges HP (A), HP (B), and HP (P) performed at the same time do not always have to be the same, and the time may be shifted from each other.
[0037]
  FIG. 3 is a timing chart of the oil nozzle air purge of the gas turbine combustor according to the second embodiment of the present invention, and is an example in which only the air purge is performed without using water. First, in the main B system where coking is most likely to occur,ChangeAfter t₀= After 5 seconds, the low pressure air purge LP (B ′) is t₁₁= 120 seconds, the pressure is increased at the cabin pressure + 0.7 bar. Then t₁₂= After 5 seconds, the low pressure air purge LP (A ′) is t in the main A system.₁₃= 60 seconds, the pressure is similarly set to +0.7 bar, then t₁₄= Low pressure air purge LP (P) t in pilot system after 5 seconds₁₅= 315 seconds, pressure is +0.3 bar and finally t₁₆= High pressure air purge HP (A), HP (B), HP (P) at the same time after 5 seconds₁₇= 30 seconds, pressure is +1.3 bar.
[0038]
In the second embodiment described above, the water purge W (B) of the first embodiment shown in FIG. 2 is eliminated, and only the air purge LP (B ′) is used in the main B system. t₁₁= It is carried out with a length of about 120 seconds. This second embodiment is a particularly effective method when there is no water facility, and is an economical method because water is not used, and the same effect as the first embodiment can be obtained. It is.
[0039]
FIG. 4 is a timing diagram of an oil nozzle purging method for a gas turbine combustor according to a third embodiment of the present invention. In the figure, in the third embodiment, water purging W (A) is added to the main A system in the system of the first embodiment shown in FIG. is there. In the third embodiment, water purging can also be performed in the main A system, so this is an effective method when coking is likely to occur in the A system for some reason. It has the same effect.
[0040]
  FIG. 5 is a timing diagram of an oil nozzle purging method for a gas turbine combustor according to a fourth embodiment of the present invention. In the figure, T is the fuel switching time, during which the fuel is switched from oil to gas.ChangeFirst, the pilot system switches from oil to gas.ChangeThen, the main system is switched from oil to gas. In the main A and B systems, the water injection W / I is made in the oil fuel before the fuel switching time T, the water injection is stopped immediately before the switching, and then the fuel is cut in the order of the pilot system and the main A and B systems. Change.
[0041]
After the fuel is switched, the water purge W is first performed in the main A and B systems, and then the main A and B systems and the pilot system are simultaneously purged with low pressure air.₁Followed by high pressure purge HP with high pressure air, followed by low pressure purge LP with low pressure air₂Perform for a relatively long time. The air purge time in this case is LP as shown in the figure.₂> LP₁It is preferred to purge as> HP.
[0042]
The fourth embodiment has an effect of preventing coking as in the third embodiment, but the oil remaining for a short time Δt until the oil runs out and the water purge W starts is short. Although it is time, it will be exposed to high temperatures. When the number of purges overlaps, there is a risk of coking, and there is a method of the fifth embodiment shown in FIG. 6 to prevent coking more reliably.
[0043]
FIG. 6 is a timing chart of an oil nozzle purge method for a gas turbine combustor according to a fifth embodiment of the present invention. In the figure, the oil fuel runs out and switches to gas at the fuel switching time T, but before the switching, the water purge WP is performed on the oil fuel, water is mixed into the oil fuel, and the flow rate of the oil fuel is gradually increased as the switching proceeds. At the end of switching, only water flows in the oil nozzle, and the water purge WP is continued for a predetermined time from the end of switching. After the water purge WP is cut off, for example, after 5 seconds, the low pressure air purge LP_ThreeFor a predetermined time, followed by lower pressure air purge LP_FourFor a predetermined time. Air purge LP_ThreeIs a purge in place of the air purges LP and HP shown in FIG. 5, and the above-described water purge is extended, so that a high-pressure HP purge is unnecessary.
[0044]
In the fifth embodiment described above, even when the water purge WP completes the fuel switching, the water purge is continuously performed, so that oil remains and is not exposed to high temperatures. Further, since the water purge WP continues even when the fuel is switched, the remaining oil is reduced, and the oil is not pushed out and the load is not suddenly changed.
[0045]
In the fourth and fifth embodiments, the water purge W, WP, air purge LP only for the main A and B systems.₁, LP₂, LP_Three, LP_FourAlthough an example of performing HP has been described, the same air purge may be performed in the pilot system, and the pilot system may naturally perform the air purge shown in FIG.
[0046]
  In the first to fifth embodiments described above, the control of the air purge and water purge timing is already performed by the control device 10. As shown in FIG. 1, the control device 10 receives a fuel switching signal S and a vehicle interior pressure P, and these signals cause the main A system.21Control valve 4 of water system and control valve 2 of air system connected to7, Main B system22Control valve 5 of water system and control valve 28 of air system connected to the pilot system20Each air system control valve 26 is controlled.
[0047]
  The control device 10 stores in advance the opening / closing sequence of each valve at each timing shown in FIGS.ChangeStarting with the signal S, the pressure to be increased is calculated from the signal of the vehicle interior pressure P, and the opening of the control valve is controlled to be the pressure, and each control valve is controlled based on the set timing. Open and close.
[0048]
In the first to fifth embodiments described above, an example of air purge has been described. However, instead of air, N₂Even if gas or fuel gas is used, the same effect can be obtained. These air, N₂Gas and fuel gas temperatures of 100 ° C. or lower are used. Since the residual oil causes coking at a temperature of about 150 ° C. to 160 ° C., it is preferable to use air or gas of 150 ° C. to 160 ° C. or less that does not cause coking.
[0049]
【The invention's effect】
  The oil nozzle purge method for a gas turbine combustor according to the present invention includes: (1) an oil nozzle for a gas turbine combustor that can be used by switching between oil and gas fuel and that has three fuel supply systems: main A, main B, and pilot. The fuel from oil to gasChangeBasically, water or gas is passed through each of the main A, main B, and pilot systems in a time-sharing manner for a predetermined time, and finally gas is passed simultaneously for a predetermined time to purge oil remaining in each system. It's a way. By purging the three systems separately and at different timings by such a method, a large amount of residual oil is not pushed out to the combustor in a short time, which causes fluctuations in the output of the gas turbine. There is no. In addition, since the three systems are purged with gas at the same time, the residual oil can be completely pushed out.
[0050]
  In (2) of the present invention, the main B system where coking is most likely to occur is first purged with water. Next, the main A system, the main B system, and then the pilot system are purged at different timings in a time-sharing manner, so that the residual oil in the main B system, which is most likely to cause coking, can be reliably purged.Further, in the invention of (3), since the purging is performed only with the gas without using water, the purging can be easily performed with only the gas easily even when there is no water supply facility.
[0051]
  (4), The pressure of the last gas purge is higher than the pressure of the gas purge performed before, and the time is shortened, and the oil remaining at the end is pushed out instantaneously.5In the invention of (3), the last purge is also carried out so that the time is shifted in each of the three systems so that the remaining oil flows out smoothly and continuously, not simultaneously, so that there is no fluctuation in the output of the gas turbine due to the purge. To do.
[0052]
  or(6In the invention of), since coking is relatively difficult to occur in the pilot system, the gas purge pressure can be lowered to reduce the amount of gas used.. FurtherIn the invention of (7), since the gas uses air, it is not necessary to use other expensive gas, and there is no need for gas recovery, etc., and purging can be easily performed only with air equipment. it can.
[0053]
In (8) of the present invention, in the oil nozzle of a gas turbine combustor that can be used by switching between oil and gas fuel and the fuel supply system has three systems of main A, main B, and pilot, the water purge is the main A In both systems B and B, the fuel is mixed into the fuel oil before the change from oil to gas and is continued for a predetermined time after the fuel change, and then the gas purge is performed in a time division manner. With such a configuration, even if the water purge is completed after the fuel switching is completed, the water purge is continuously performed, so that oil remains and is not exposed to a high temperature. Further, since the water purge is continued even when the fuel is switched, the remaining oil is reduced, and the oil is not pushed out and the load is not suddenly changed.
[Brief description of the drawings]
FIG. 1 is a system diagram of an apparatus for carrying out an oil nozzle purging method for a gas turbine combustor according to first to third embodiments of the present invention.
FIG. 2 is a timing chart of the oil nozzle purging method according to the first embodiment of the present invention.
FIG. 3 is a timing diagram of an oil nozzle purging method according to a second embodiment of the present invention.
FIG. 4 is a timing diagram of an oil nozzle purging method according to a third embodiment of the present invention.
FIG. 5 is a timing diagram of an oil nozzle purging method according to a fourth embodiment of the present invention.
FIG. 6 is a timing chart of an oil nozzle purge method according to a fifth embodiment of the present invention.
FIG. 7 is a typical sectional view of a nozzle of a dual type gas turbine combustor.
FIG. 8 is a front view of the combustor nozzle shown in FIG. 5;
9 is a cross-sectional view showing a tip portion of a main nozzle in the combustor nozzle shown in FIG.
FIG. 10 is a diagram of a purge system in a conventional dual type fuel system.
[Explanation of symbols]
1 Water tank
2,3 piping
4,5 Control valve
10 Control device
20 Pilot system
21 Main A system
22 Main B system
23 Distributor
24 header
25A, 25B, 25P Piping
26, 27, 28 Control valve
29 Air tank
50 combustor
60 Gas turbine

Claims (8)

  In an oil nozzle of a gas turbine combustor that can be used by switching between oil and gas fuel and the fuel supply system has three systems of main A, main B, and pilot, the main A is immediately after the fuel is switched from oil to gas. Purging oil remaining in each system by passing water or gas through each of the main B and pilot systems in a time-sharing manner for a predetermined time and finally passing gas simultaneously for a predetermined time. Method.   The use of water or gas in the time division is as follows: first, water in the main B system, then gas in the main A system, then gas in the main B system, then gas in the pilot system, and finally in the three systems simultaneously. 2. The method of purging an oil nozzle in a gas turbine combustor according to claim 1, wherein the method is performed with gas. The purge claim 1 Symbol placement of oil nozzle purging method for a gas turbine combustor, characterized in that all are performed only with gas. The oil nozzle purge method for a gas turbine combustor according to any one of claims 1 to 3, wherein the last gas purge has a pressure higher than that of the previous gas purge and is shorter in time. The oil nozzle purge method for a gas turbine combustor according to any one of claims 1 to 3, wherein the last gas purge is performed at different times instead of being simultaneously passed through each of the three systems. Gas purge the main A in the pilot system, the oil nozzle purging method for a gas turbine combustor according to any one of claims 1 to 3, characterized in that lower than the pressure of the gas purging in the main B lineage.   The oil nozzle purge method for a gas turbine combustor according to any one of claims 1 to 6, wherein the gas is air.   In the oil nozzle of a gas turbine combustor that can be used by switching between oil and gas fuel and the fuel supply system has three main A, main B, and pilot systems, the water purge is simultaneously performed in both the main A and B systems, and An oil nozzle purge method for a gas turbine combustor, characterized in that the fuel is mixed into the fuel oil before switching from oil to gas and is continued for a predetermined time after the fuel switching, and then gas purge is performed in a time-sharing manner thereafter.

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