Method for shutting down combustion equipment

Abstract

To provide a shutdown method for a combustion apparatus capable of executing shutdown processing safely without igniting residual fuel after extinguishment of flame.SOLUTION: In a shutdown method for a combustion apparatus 1, the combustion apparatus 1 includes: a combustion chamber 11; a fuel jetting part 12 for jetting fuel; an oxidant jetting part 13 for jetting an oxidant; a fuel supply pipe 22 for supplying fuel to the fuel jetting part 12; an oxidant supply pipe 32 for supplying an oxidant to the oxidant jetting part 13; and a purge medium supply pipe 41 for supplying a purge medium to be supplied to the fuel jetting part 12 to the fuel supply pipe 22. While a flame is formed, the purge medium is supplied from the purge medium supply pipe 41 to the fuel supply pipe 22 to extinguish the flame. After extinguishment of the flame, while supply of the purge medium to the fuel supply pipe 22 is continued, supply of the fuel to the fuel supply pipe 22 is shut off, and after the shut-off of the fuel supply, supply of the purge medium to the fuel supply pipe 22 is continued for a predetermined time.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] An embodiment of the present invention relates to a method for shutting down a combustion device. [Background technology]

[0002] In a conventional combustion apparatus equipped with a combustor of a diffusion combustion type, the combustor includes a fuel ejection pipe that ejects fuel into a combustion region, and an oxidizer ejection pipe that ejects an oxidizer into the combustion region from around the fuel ejection pipe.

[0003] When the operation of this combustion device is stopped, after the fuel supply is cut off, air may enter the fuel injection pipe and mix with the remaining fuel, forming a flammable mixture. This mixture may then be ignited by the high temperature part of the combustor. This not only poses a safety problem, but may also cause damage to the combustor.

[0004] In order to prevent ignition of remaining fuel when the operation of such a combustion device is stopped, a process of purging the inside of the fuel injection pipe with air may be carried out in a conventional combustion device using a diffusion combustion method after the fuel is shut off. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-51717 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned conventional combustion apparatus using the diffusion combustion method, when the inside of the fuel injection pipe is purged with air after the fuel is cut off, depending on the flow rate of the air flowing through the fuel injection pipe, the remaining fuel and air may locally mix to form a flammable mixture. This mixture may then be ignited by the high temperature part of the combustor as an ignition source.

[0007] That is, in a conventional combustion device using a diffusion combustion method, even if a purge process using air is performed after the fuel supply is cut off in order to prevent the remaining fuel from igniting, a flammable mixture may be formed during the purge process and may ignite.

[0008] An object of the present invention is to provide a method for shutting down a combustion apparatus, which can safely shut down the apparatus without igniting the remaining fuel after the flame is extinguished. [Means for solving the problem]

[0009] In an embodiment of a method for stopping operation of a combustion device, the combustion device includes a combustion chamber for combusting fuel and an oxidizer, a fuel ejection section for ejecting fuel into the combustion chamber, an oxidizer ejection section for ejecting oxidizer into the combustion chamber, a fuel supply pipe for supplying fuel to the fuel ejection section, an oxidizer supply pipe for supplying oxidizer to the oxidizer ejection section, and a purge medium supply pipe for supplying a purge medium to be supplied to the fuel ejection section to the fuel supply pipe.

[0010] Then, when a flame is formed, the purging medium is supplied from the purging medium supply pipe to the fuel supply pipe to extinguish the flame, and after the flame is extinguished, the supply of fuel to the fuel supply pipe is cut off while continuing to supply the purging medium to the fuel supply pipe, and after the fuel supply is cut off, the supply of the purging medium to the fuel supply pipe is continued for a predetermined time. Effect of the Invention

[0011] According to the method for shutting down the operation of a combustion apparatus of the present invention, the operation shutdown process can be safely performed without igniting the remaining fuel after the flame is extinguished. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a schematic configuration of a combustion apparatus employing an operation shutdown method according to a first embodiment. [Diagram 2]1 is a block diagram showing a configuration of a control device that executes control for stopping operation in a combustion apparatus that employs an operation stopping method according to a first embodiment. FIG. [Diagram 3] 4 is a time chart for explaining a method for stopping the operation of the combustion apparatus according to the first embodiment. [Figure 4] 4 is a flowchart for explaining a method for stopping operation of the combustion apparatus according to the first embodiment. [Diagram 5] FIG. 4 is a diagram showing a schematic configuration of a combustion apparatus employing an operation shutdown method according to a second embodiment. [Figure 6] FIG. 11 is a diagram showing a schematic configuration of a combustion apparatus employing an operation shutdown method according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] (First embodiment) FIG. 1 is a diagram showing a schematic configuration of a combustion apparatus 1 that employs a shutdown method according to a first embodiment.

[0015] 1, the combustion device 1 includes a combustor 10, a fuel supply system 20, an oxidant supply system 30, a purge medium supply system 40, and a control device 50. Note that, here, the combustion device 1 utilizing exhaust gas recirculation (EGR) is illustrated as an example.

[0016] The combustor 10 is a diffusion combustion type combustor in which fuel and an oxidizer are separately injected into a combustion chamber 11. The combustor 10 includes the combustion chamber 11, a fuel injection section 12, and an oxidizer injection section 13. The combustor 10 also includes a flame detection section 14 that detects a flame.

[0017] The combustion chamber 11 is a cylindrical body in which fuel and an oxidizer are combusted. A flame is formed within the combustion chamber 11.

[0018] The fuel ejection part 12 ejects fuel into the combustion chamber 11. The fuel ejection part 12 is composed of a tubular member. The tubular member constituting the fuel ejection part 12 has a predetermined length in the longitudinal direction. The fuel ejection part 12 is provided at one end of the combustion chamber 11, for example. Specifically, one end (outlet end) of the fuel ejection part 12 is connected to one end of the combustion chamber 11, for example.

[0019] The oxidizer ejection part 13 ejects an oxidizer into the combustion chamber 11. The oxidizer ejection part 13 is configured, for example, by an annular flow path between a tubular member constituting the fuel ejection part 12 and a tubular member surrounding the outer periphery of the fuel ejection part 12. The oxidizer ejection part 13 has a predetermined length in the longitudinal direction, similar to the fuel ejection part 12. The tubular member surrounding the outer periphery of the fuel ejection part 12 is provided, for example, at one end of the combustion chamber 11. Specifically, one end (outlet end) of the tubular member surrounding the outer periphery of the fuel ejection part 12 is connected to, for example, one end of the combustion chamber 11.

[0020] The above-mentioned fuel ejection section 12 and oxidizer ejection section 13 are configured, for example, with a double-pipe structure, in which fuel is ejected from the center and oxidizer is ejected in a ring shape from the periphery of the combustion. Note that the configurations of the fuel ejection section 12 and the oxidizer ejection section 13 are merely examples and are not limited to the above-mentioned configurations. The configurations of the fuel ejection section 12 and the oxidizer ejection section 13 may be any configuration that ejects fuel or oxidizer into the combustion chamber 11 separately.

[0021] The flame detection unit 14 detects the formation of a flame. Note that the flame detection unit 14 may be a detector capable of detecting a flame, and the detection method is not particularly limited.

[0022] The fuel supply system 20 supplies fuel to the fuel ejection unit 12. The fuel supply system 20 includes a fuel supply source 21, a fuel supply pipe 22, and a flow rate adjustment unit .

[0023] The fuel supply source 21 stores fuel to be supplied to the fuel supply pipe 22. The fuel supply pipe 22 connects the fuel supply source 21 and the fuel ejection portion 12, and supplies the fuel supplied from the fuel supply source 21 to the fuel ejection portion 12.

[0024] The flow rate adjusting unit 23 is disposed in the fuel supply pipe 22 and adjusts the flow rate of the fuel supplied to the fuel ejection unit 12. The flow rate adjusting unit 23 is configured, for example, with a flow rate adjustment valve. The flow rate adjusting unit 23 is provided, for example, between the fuel supply source 21 and a connection unit 22a where a purge medium supply pipe 41 described later is connected to the fuel supply pipe 22.

[0025] Here, the state of the fuel supplied to the fuel ejection portion 12 is gas. The type of fuel is not particularly limited. Examples of the fuel include hydrocarbons, hydrogen, and ammonia. In addition, examples of the fuel include a mixed fuel in which some of these are mixed.

[0026] The oxidizing agent supply system 30 supplies an oxidizing agent to the oxidizing agent jetting unit 13. The oxidizing agent supply system 30 includes an oxidizing agent supply source 31, an oxidizing agent supply pipe 32, and a flow rate adjusting unit 33.

[0027] The oxidant supply source 31 supplies the oxidant to the oxidant jetting portion 13 via the oxidant supply pipe 32. When the oxidant is air, the oxidant supply source 31 is composed of, for example, a fan, a blower, a compressor, etc. When the oxidant is oxygen, the oxidant supply source 31 is composed of, for example, an oxygen cylinder that stores high-pressure oxygen. The oxidant supply pipe 32 connects the oxidant supply source 31 and the oxidant jetting portion 13, and supplies the oxidant supplied from the oxidant supply source 31 to the oxidant jetting portion 13.

[0028] The flow rate adjusting unit 33 is disposed in the oxidizer supply pipe 32, and adjusts the flow rate of the oxidizer supplied to the oxidizer jetting unit 13. The flow rate adjusting unit 33 is configured with, for example, a damper, a flow rate adjusting valve, and the like.

[0029] Here, air is used as the oxidizing agent. Alternatively, oxygen may be used as the oxidizing agent. For example, when hydrogen is used as the fuel and oxygen is used as the oxidizing agent, the combustion gas becomes water vapor.

[0030] 1, the oxidant supply system 30 may include a heat exchanger 34 that exchanges heat between the oxidant and a purge medium flowing through a purge medium supply pipe 41 described later. The heat exchanger 34 is provided in the oxidant supply pipe 32 between the flow rate adjustment unit 33 and the oxidant supply source 31, for example.

[0031] Such an arrangement of the heat exchanger 34 is suitable when the temperature of the purge medium is higher than the temperature of the oxidant flowing through the oxidant supply pipe 32 and it is desired to lower the temperature of the purge medium.

[0032] The purge medium supply system 40 supplies a purge medium to the fuel supply pipe 22 to remove fuel remaining in the fuel ejection part 12. The purge medium supply system 40 includes a purge medium supply pipe 41, a purge medium pumping part 42, and a flow rate adjusting part 43. Here, a case where the gas in the combustion chamber 11 of the combustor 10 is used as the purge medium will be exemplified.

[0033] Here, the gas in the combustion chamber 11 is called the combustion chamber gas. The combustion chamber gas includes not only the gas in the combustion chamber 11, but also the gas in the exhaust pipe through which the exhaust gas from the combustion chamber 11 passes. In a combustion state, the combustion chamber gas is a combustion gas generated by the combustion of the fuel and the oxidizer. After the flame is extinguished, the combustion chamber gas is a gas mainly composed of air.

[0034] The purge medium supply pipe 41 supplies the fuel supply pipe 22 with a purge medium to be supplied to the fuel ejection part 12. One end of the purge medium supply pipe 41 is inserted, for example, into the combustion chamber 11 so that the gas in the combustion chamber can be introduced. Note that, for example, one end of the purge medium supply pipe 41 may be inserted into an exhaust pipe or the like that exhausts the gas in the combustion chamber from the combustion chamber 11. The other end of the purge medium supply pipe 41 is connected to the fuel supply pipe 22.

[0035] The purge medium supply pipe 41 is configured to have a heat exchanger 34 interposed therebetween so as to enable heat exchange between the purge medium and the oxidant. In addition, the purge medium supply pipe 41 may be connected to, for example, an oxidant supply branch pipe 35 that introduces a portion of the oxidant from the oxidant supply pipe 32, as shown in FIG.

[0036] When the oxidant supply branch pipe 35 is provided, one end of the oxidant supply branch pipe 35 is connected, for example, to the purge medium supply pipe 41 between the heat exchanger 34 and the connecting portion 22a. The other end of the oxidant supply branch pipe 35 is connected to the oxidant supply pipe 32 between the heat exchanger 34 and the oxidant supply source 31. A flow rate adjustment unit 36 ​​that adjusts the flow rate of the oxidant introduced into the purge medium supply pipe 41 is interposed in the oxidant supply branch pipe 35. The flow rate adjustment unit 36 ​​is formed, for example, of a flow rate adjustment valve.

[0037] In this example, the combustion device 1 utilizes exhaust gas recirculation (EGR) to mix a portion of the combustion gas generated in the combustor 10 with an oxidizer during normal operation, and therefore an EGR pipe 37 is provided to introduce the combustion gas into the oxidizer supply pipe 32.

[0038] One end of the EGR pipe 37 is connected to the purge medium supply pipe 41, and the other end of the EGR pipe 37 is connected to the oxidant supply pipe 32. A flow rate adjustment unit 38 that adjusts the flow rate of the combustion gas introduced into the oxidant supply pipe 32 is interposed in the EGR pipe 37. The flow rate adjustment unit 38 is formed of, for example, a flow rate adjustment valve.

[0039] The flow rate adjusting unit 43 adjusts the flow rate of the gas in the combustion chamber that is supplied to the fuel supply pipe 22. The flow rate adjusting unit 43 is configured with, for example, a flow rate adjustment valve. The flow rate adjusting unit 43 is interposed in the purge medium supply pipe 41 between the heat exchanger 34 and a connecting portion 41a between the EGR pipe 37 and the purge medium supply pipe 41.

[0040] The purge medium pumping unit 42 has a pumping function for introducing the gas inside the combustion chamber from one end of the purge medium supply pipe 41 and discharging the gas inside the combustion chamber from the other end of the purge medium supply pipe 41 to the fuel supply pipe 22. The purge medium pumping unit 42 is, for example, disposed in the purge medium supply pipe 41 upstream of the connecting unit 41a. The purge medium pumping unit 42 is, for example, configured with a fan, a blower, or the like.

[0041] The control device 50 controls, for example, the flow rate adjustment unit 23 of the fuel supply system 20, the oxidant supply source 31 and flow rate adjustment unit 33 of the oxidant supply system 30, the purge medium pressure feeding unit 42 and flow rate adjustment unit 43 of the purge medium supply system 40, the flow rate adjustment unit 38 of the EGR piping 37, and the flow rate adjustment unit 36 ​​of the oxidant supply branch pipe 35, based on an operation command signal input from the outside, a signal from the flame detection unit 14, etc.

[0042] FIG. 2 is a block diagram showing the configuration of a control device 50 that executes control to stop operation in the combustion apparatus 1 that employs the operation stopping method of the first embodiment.

[0043] As shown in FIG. 2, the control device 50 includes an input unit 60, a storage unit 70, a calculation unit 75, and an output unit 61.

[0044] The input unit 60 inputs an input signal from an external input means such as a control panel, and detection signals from various detection units, etc. The input unit 60 inputs, for example, a signal related to operation stop from an external input means, and a detection signal from the flame detection unit 14, etc.

[0045] The storage unit 70 is configured with a storage medium such as a read only memory (ROM) or a random access memory (RAM), etc. The storage unit 70 includes a purge medium supply storage unit 71.

[0046] The purge medium supply storage unit 71 stores, for example, data for controlling the flow rate adjustment unit 43, the purge medium pressure-feeding unit 42, and the flow rate adjustment units 33, 36, and 38 when supplying the purge medium. The purge medium supply storage unit 71 also stores, for example, various programs and various data for executing control to stop operation of the combustion device 1.

[0047] The calculation unit 75 executes various calculation processes and determination processes using, for example, programs and data stored in the storage unit 70. The calculation unit 75 includes a purge medium supply determination unit 76 and a flame extinction determination unit 77.

[0048] The purge medium supply determination unit 76 determines, based on an input signal, whether or not to execute an operation shutdown process in the combustion device 1. When executing the operation shutdown process, the purge medium supply determination unit 76 controls the purge medium pressure-feed unit 42, the flow rate adjustment units 33, 36, 38, 43, and the like, based on data stored in the memory unit 70, and the like.

[0049] The flame extinction determination unit 77 determines whether or not the flame has been extinguished based on the detection signal from the flame detection unit 14. The flame extinction determination unit 77 also controls the flow rate adjustment unit 23 and the like based on the flame extinction determination result. Furthermore, the flame extinction determination unit 77 outputs a misfire alarm for the combustion device 1 based on the detection signal from the flame detection unit 14, information on the opening degree of the flow rate adjustment unit 23, and the like.

[0050] The output unit 61 outputs, for example, a control signal from the purge medium supply determination unit 76 to the flow rate adjustment unit 43 and the purge medium pressure-feeding unit 42. In addition, the output unit 61 outputs a signal related to a misfire alarm to an external device such as a display panel or an alarm transmitter.

[0051] Here, the processes executed by the control device 50 described above are realized by, for example, a computer device.

[0052] Next, the operation of the combustion device 1 will be described.

[0053] First, the action of the combustion device 1 during steady operation will be described.

[0054] During steady operation, fuel is supplied to the fuel ejection unit 12 via the fuel supply pipe 22. The oxidant is supplied to the oxidant ejection unit 13 via the oxidant supply pipe 32. In the combustion device 1 using exhaust gas recirculation (EGR), a part of the combustion gas is introduced into the oxidant supply pipe 32 via the EGR pipe 37. At this time, the purge medium pressure-feed unit 42 is also used for pressure-feeding the combustion gas to the EGR pipe 37.

[0055] Then, in the combustion chamber 11, the fuel ejected from the fuel ejection portion 12 and the oxidizer including the combustion gas ejected from the oxidizer ejection portion 13 are combusted to form a flame.

[0056] During steady operation, the flow rate adjusting unit 43 of the purge medium supply pipe 41 is closed. When the oxidant supply branch pipe 35 is provided, the flow rate adjusting unit 36 ​​is closed during steady operation.

[0057] Next, the operation of the combustion apparatus 1 when the operation is stopped will be described.

[0058] Here, Fig. 3 is a time chart for explaining the method for stopping the operation of the combustion apparatus 1 according to the first embodiment, and Fig. 4 is a flowchart for explaining the method for stopping the operation of the combustion apparatus 1 according to the first embodiment.

[0059] The purge medium supply determining unit 76 of the control device 50 determines whether or not an operation stop signal has been input (step S10).

[0060] When it is determined in step S10 that the operation stop signal has not been input (No in step S10), the purge medium supply determining unit 76 executes the determination in step S10 again.

[0061] When it is determined in step S10 that an operation stop signal has been input (Yes in step S10), the purge medium supply determination unit 76 executes a process for supplying the purge medium to the fuel supply pipe 22 via the purge medium supply pipe 41 (step S11). Here, in FIG. 3, time t1 is the time when the supply of the purge medium to the fuel supply pipe 22 via the purge medium supply pipe 41 is started.

[0062] In step S11, the purge medium supply determination unit 76 refers to the purge medium supply storage unit 71 and outputs a control signal for controlling the opening degree of the flow rate adjustment unit 43, the rotation speed of the purge medium pumping unit 42, etc., to the output unit 61. Then, the output unit 61 outputs the control signal to the flow rate adjustment unit 43 and the purge medium pumping unit 42.

[0063] 3, the supply of the purge medium is started at time t1, and at time t2, a specified flow rate of the purge medium is supplied to the fuel supply pipe 22. The temperature of the purge medium supplied to the fuel supply pipe 22 is lowered by heat exchange with the oxidizer in the heat exchanger 34. The purge medium is mixed with the fuel in the fuel supply pipe 22 and supplied to the fuel ejection part 12. That is, the fuel diluted with the purge medium is ejected from the fuel ejection part 12.

[0064] The specified flow rate of the purge medium is set to a flow rate that can extinguish the flame formed in the combustion chamber 11. The specified flow rate of the purge medium is set, for example, based on the oxygen concentration contained in the gas in the combustion chamber. Note that the mixture is formed by mixing the gas in the combustion chamber containing oxygen with the fuel, and the specified flow rate of the purge medium is set so that the fuel concentration in this mixture is below the lower explosion limit. The specified flow rate of the purge medium may also be set so that the flow velocity of the mixture ejected from the fuel ejection portion 12 is greater than the combustion velocity of this mixture.

[0065] Here, when a flame is formed in the combustion chamber 11, the oxygen concentration of the purge medium when the gas in the combustion chamber 11 is used as the purge medium is, for example, about 1 / 5 of the oxygen concentration of the purge medium when air is used as the purge medium. Therefore, when the gas in the combustion chamber 11 is used as the purge medium, a combustible mixture is less likely to be formed in the fuel supply pipe 22 and the fuel ejection part 12 than when air is used as the purge medium.

[0066] That is, the specified flow rate of the purge medium is set to satisfy at least one of the following conditions: the fuel concentration in the mixture is set below the lower explosion limit, or the flow velocity of the mixture ejected from the fuel ejection portion 12 is set to be greater than the combustion velocity of the mixture. The specified flow rate of the purge medium may also be set to satisfy both of the above conditions.

[0067] Next, the flame extinction determination unit 77 determines whether or not the flame has been extinguished based on the signal from the flame detection unit 14 (step S12).

[0068] When it is determined in step S12 that the flame is not extinguished (No in step S12), the flame detection unit 14 executes the determination in step S12 again.

[0069] If it is determined in step S12 that the flame has been extinguished (Yes in step S12), the flame detection unit 14 executes a process for cutting off the supply of fuel to the fuel supply pipe 22 (step S13). In Fig. 3, the time t3 is the time when the flame extinguishing determination unit 77 determines that the flame has been extinguished. When the flame has been extinguished (time t3), the output of the combustion device 1 becomes zero.

[0070] In the process of step S13, flame detection unit 14 outputs a control signal to output unit 61 to close flow rate adjustment unit 23 of fuel supply pipe 22. Then, output unit 61 outputs the control signal to flow rate adjustment unit 23. In Fig. 3, time t4 is the time when flow rate adjustment unit 23 is closed.

[0071] Here, the flame extinction determination unit 77 performs the determination within a response time of, for example, about 2 seconds. When the flame extinction determination unit 77 determines that the flame has been extinguished, after the response time has elapsed after the determination, it performs a determination as to, for example, whether the flow rate adjustment unit 23 is closed or not. When it determines that the flow rate adjustment unit 23 is not closed, the flame extinction determination unit 77 outputs a signal for outputting a misfire alarm to the output unit 61. Then, the output unit 61 outputs the signal related to the misfire alarm to a display panel, an alarm transmitter, or the like.

[0072] 3, the time from when it is determined that the flame has gone out (time t3) to when the flow rate adjustment unit 23 is closed (time t4) (the time from time t3 to time t4) is set to be shorter than the response time. As a result, even if a state exists in which the flow rate adjustment unit 23 is not closed after it is determined that the flame has gone out, a misfire alarm is not output.

[0073] Here, no flame exists between time t3 and time t4. Furthermore, fuel is injected into the combustion chamber 11 without the presence of a flame between time t3 and time t4. Therefore, the purge medium becomes air mixed with a small amount of fuel. However, the period between time t3 and time t4 is short, and even if the purge medium contains fuel, the fuel concentration in the mixture flowing through the fuel supply pipe 22 is below the lower explosion limit. Note that even after the flame is extinguished (after time t3), a specified flow rate of purge medium is supplied to the fuel supply pipe 22.

[0074] 3, after flow rate adjustment unit 23 is closed at time t4, the fuel present in fuel supply pipe 22 and fuel ejection unit 12 is ejected, and the flow rate of fuel ejected into combustion chamber 11 becomes zero at time t5. In addition, the purge medium after time t5 when no fuel is present becomes air.

[0075] Here, when the oxidant supply branch pipe 35 is provided, after the flame is extinguished (after time t3), the flow rate adjustment unit 36 ​​may be opened and a part of the air flowing through the oxidant supply pipe 32 may be supplied as a purge medium to the fuel supply pipe 22 via the oxidant supply branch pipe 35. In this case, the supply of the purge medium from the combustion chamber 11 by the purge medium pumping unit 42 may be stopped. In addition, after the flame is extinguished (after time t3), the flow rate adjustment unit 38 of the EGR pipe 37 may be closed.

[0076] Next, the purge medium supply determining unit 76 determines whether or not a predetermined time has elapsed since the fuel supply was cut off (step S14). The purge medium supply determining unit 76 also has a function of counting time.

[0077] When it is determined in step S14 that the predetermined time has not elapsed (No in step S14), the purge medium supply determining unit 76 executes the determination in step S14 again.

[0078] If it is determined in step S14 that the predetermined time has elapsed (Yes in step S14), the purge medium supply determination unit 76 executes a process for stopping the supply of the purge medium to the fuel supply pipe 22 (step S15). In step S15, the purge medium supply determination unit 76 outputs a control signal for closing the flow rate adjustment unit 43 and a control signal for stopping the purge medium pumping unit 42 to the output unit 61. Then, the output unit 61 outputs the control signals to the flow rate adjustment unit 43 and the purge medium pumping unit 42.

[0079] As shown in Fig. 3, even after the fuel supply is cut off, a specified flow rate of purge medium is supplied to the fuel supply pipe 22 and the fuel ejection part 12 via the purge medium supply pipe 41. Then, the supply of the purge medium is stopped when a predetermined time has elapsed after the fuel supply is cut off. Here, in Fig. 3, time t6 is the time when a predetermined time has elapsed after the fuel supply is cut off. In other words, time t6 is the time when the supply of the purge medium is stopped.

[0080] In addition, in FIG. 3, after the flow rate adjustment unit 43 is closed at time t6, the purge medium present in the purge medium supply pipe 41, the fuel supply pipe 22, and the fuel ejection unit 12 is ejected, and the flow rate of the purge medium ejected into the combustion chamber 11 becomes zero at time t7.

[0081] As described above, in the method for shutting down the operation of the combustion apparatus 1 according to the first embodiment, a purge medium can be supplied to the fuel supply pipe 22 to extinguish the flame before the supply of fuel is cut off.

[0082] Even after the flame is extinguished, the same specified flow rate of purge medium as that during flame extinguishing is supplied to the fuel supply pipe 22 and the fuel ejection portion 12, so that the fuel concentration in the mixture of the purge medium and fuel remains below the lower explosion limit.

[0083] In addition, even after the fuel supply is cut off, the same specified flow rate of purge medium as that used for extinguishing the flame is supplied to the fuel supply pipe 22 and the fuel ejection portion 12, so that even if fuel remains and an air-fuel mixture is formed, the fuel concentration in the mixture is below the lower explosion limit.

[0084] Furthermore, by continuing to supply the purge medium even after the flame is extinguished, for example, the combustion chamber 11, the fuel ejection part 12, and the oxidizer ejection part 13 in the combustor 10 are cooled. As a result, no high-temperature part that could become an ignition source is generated in the components of the combustor 10, so that, for example, even if a flammable mixture is formed, it will not ignite.

[0085] In this way, according to the method for shutting down the operation of the combustion apparatus 1 of the first embodiment, the remaining fuel is not ignited during the purging process, and the operation shutdown process can be executed safely.

[0086] (Second embodiment) 5 is a diagram showing a schematic configuration of a combustion apparatus 2 employing the operation shutdown method of the second embodiment. In the following embodiments, the same components as those of the combustion apparatus 1 employing the operation shutdown method of the first embodiment are given the same reference numerals, and duplicated explanations are omitted or simplified.

[0087] The combustion apparatus 2 employing the operation shutdown method of the second embodiment uses air as a purge medium, and therefore the configuration of the purge medium supply system 40A is different from the configuration of the purge medium supply system 40 in the combustion apparatus 1 employing the operation shutdown method of the first embodiment. Therefore, the configuration of the purge medium supply system 40A will be mainly described here. Note that exhaust gas recirculation (EGR) is not used in the combustion apparatus 2.

[0088] As shown in FIG. 5, the combustion device 2 includes a combustor 10, a fuel supply system 20, an oxidant supply system 30A, a purge medium supply system 40A, and a control device 50.

[0089] The combustor 10 and the fuel supply system 20 are as described in the first embodiment. The oxidizing agent supply system 30A is the same as the oxidizing agent supply system 30 in the first embodiment, except that it does not include a heat exchanger .

[0090] The purge medium supply system 40A supplies a purge medium to the fuel supply pipe 22 to remove fuel remaining in the fuel ejection part 12. The purge medium supply system 40A includes a purge medium supply pipe 80 and a flow rate adjustment part 81. Here, an example will be shown in which air is used as the purge medium. The air used as the purge medium is air supplied from an oxidizer supply source 31 to an oxidizer supply pipe 32.

[0091] The purge medium supply pipe 80 supplies the purge medium to the fuel supply pipe 22 for supply to the fuel ejection unit 12. One end of the purge medium supply pipe 80 is connected to the oxidizer supply pipe 32 between the oxidizer source 31 and the flow rate adjustment unit 33. The other end of the purge medium supply pipe 80 is connected to the fuel supply pipe 22 between the flow rate adjustment unit 23 and the fuel ejection unit 12.

[0092] The flow rate adjusting unit 81 adjusts the flow rate of air supplied to the fuel supply pipe 22. The flow rate adjusting unit 81 is disposed in the purge medium supply pipe 80. The flow rate adjusting unit 81 is configured with, for example, a flow rate adjustment valve.

[0093] The control device 50 controls, for example, the flow rate adjustment unit 23 of the fuel supply system 20, the oxidant supply source 31 and flow rate adjustment unit 33 of the oxidant supply system 30A, and the flow rate adjustment unit 81 of the purge medium supply system 40A, based on an operation command signal input from the outside, a signal from the flame detection unit 14, etc.

[0094] The configuration of the control device 50 is as shown in Fig. 2. Here, the purge medium supply storage unit 71 stores, for example, data for controlling the flow rate adjustment unit 81 when supplying the purge medium, the oxidant supply source 31, etc. Also, the purge medium supply storage unit 71 stores, for example, various programs and various data for executing control for stopping the operation of the combustion device 2.

[0095] When performing the operation shutdown process, the purge medium supply determination unit 76 controls the flow rate adjustment unit 81, the oxidizing agent supply source 31, etc., based on the data stored in the memory unit 70. The flame extinction determination unit 77 is as described in the first embodiment.

[0096] The output unit 61 outputs, for example, a control signal from the purge medium supply determination unit 76 to the flow rate adjustment unit 81 and the oxidizing agent supply source 31.

[0097] Next, the operation of the combustion device 2 will be described.

[0098] First, the action of the combustion device 1 during steady operation will be described.

[0099] During steady operation, fuel is supplied to the fuel ejection portion 12 through the fuel supply pipe 22. The oxidizer is supplied to the oxidizer ejection portion 13 through the oxidizer supply pipe 32. Then, in the combustion chamber 11, the fuel ejected from the fuel ejection portion 12 and the oxidizer ejected from the oxidizer ejection portion 13 combust to form a flame. During steady operation, the flow rate adjustment portion 81 of the purge medium supply pipe 80 is closed.

[0100] Next, the operation of the combustion device 2 when the operation is stopped will be described.

[0101] Here, the following mainly describes the operation of the combustion device 1 when the operation is stopped, which is different from the operation of the combustion device 1 in the first embodiment. Note that the time charts and flow charts for explaining the method for stopping the operation of the combustion device 2 are the same as those for explaining the method for stopping the operation of the combustion device 1, and therefore will be described with reference to Figs. 3 and 4.

[0102] When the purge medium supply determining unit 76 determines in step S10 that an operation stop signal has been input (Yes in step S10), the purge medium supply determining unit 76 executes a process for supplying the purge medium to the fuel supply pipe 22 via the purge medium supply pipe 80 (step S11). Here, in FIG. 3, time t1 is the time when the supply of the purge medium to the fuel supply pipe 22 via the purge medium supply pipe 80 is started.

[0103] In step S11, the purge medium supply determination unit 76 refers to the purge medium supply storage unit 71 and outputs a control signal for controlling the opening degree of the flow rate adjustment unit 81, the flow rate of air supplied from the oxidant supply source 31, and the like to the output unit 61. Then, the output unit 61 outputs the control signal to the flow rate adjustment unit 81 and the oxidant supply source 31. After the supply of the purge medium starts, the supply of air from the oxidant supply source 31 increases.

[0104] 3, the supply of the purge medium is started from time t1, and at time t2, a specified flow rate of the purge medium is supplied to the fuel supply pipe 22. The purge medium is mixed with the fuel in the fuel supply pipe 22 and supplied to the fuel ejection part 12. That is, the fuel diluted by the purge medium is ejected from the fuel ejection part 12.

[0105] The specified flow rate of the purge medium is set to a flow rate that can extinguish the flame formed in the combustion chamber 11. The mixture is formed by mixing air and fuel, and the specified flow rate of the purge medium is set so that the fuel concentration in the mixture is below the lower explosion limit. The specified flow rate of the purge medium may also be set so that the flow velocity of the mixture ejected from the fuel ejection portion 12 is greater than the combustion velocity of the mixture.

[0106] That is, the specified flow rate of the purge medium is set to satisfy at least one of the following conditions: the fuel concentration in the mixture is set below the lower explosion limit, or the flow velocity of the mixture ejected from the fuel ejection portion 12 is set to be greater than the combustion velocity of the mixture. The specified flow rate of the purge medium may also be set to satisfy both of the above conditions.

[0107] In step S14, the purge medium supply determining unit 76 determines whether or not a predetermined time has elapsed after the fuel supply was shut off (step S14).

[0108] If it is determined in step S14 that the predetermined time has elapsed (Yes in step S14), the purge medium supply determination unit 76 executes a process for stopping the supply of the purge medium to the fuel supply pipe 22 (step S15). In step S15, the purge medium supply determination unit 76 outputs a control signal for closing the flow rate adjustment unit 81 and a control signal for stopping the supply of air from the oxidant supply source 31 to the output unit 61. Then, the output unit 61 outputs the control signals to the flow rate adjustment unit 81 and the oxidant supply source 31.

[0109] 3, even after the fuel supply is cut off, a specified flow rate of the purge medium is supplied to the fuel supply pipe 22 and the fuel ejection part 12 via the purge medium supply pipe 80. Then, when a predetermined time has elapsed after the fuel supply is cut off, the supply of the purge medium is stopped.

[0110] As described above, the method for stopping the operation of the combustion apparatus 2 according to the second embodiment has the same effect as the method for stopping the operation of the combustion apparatus 1 according to the first embodiment. That is, before the supply of fuel is cut off, a purge medium can be supplied to the fuel supply pipe 22 to extinguish the flame.

[0111] Even after the flame is extinguished, the same specified flow rate of purge medium as that during flame extinguishing is supplied to the fuel supply pipe 22 and the fuel ejection portion 12, so that the fuel concentration in the mixture of the purge medium and fuel remains below the lower explosion limit.

[0112] In addition, even after the fuel supply is cut off, the same specified flow rate of purge medium as that used for extinguishing the flame is supplied to the fuel supply pipe 22 and the fuel ejection portion 12, so that even if fuel remains and an air-fuel mixture is formed, the fuel concentration in the mixture is below the lower explosion limit.

[0113] Furthermore, by continuing to supply the purge medium even after the flame is extinguished, no high temperature parts that could become an ignition source are generated in the components of the combustor 10, so that even if a flammable mixture is formed, it will not ignite.

[0114] In this way, according to the method for shutting down the operation of the combustion apparatus 2 of the second embodiment, the remaining fuel is not ignited during the purging process, and the operation shutdown process can be executed safely.

[0115] (Third embodiment) FIG. 6 is a diagram showing a schematic configuration of a combustion apparatus 3 that employs a method for shutting down operation according to the third embodiment.

[0116] The combustion apparatus 3 employing the operation shutdown method of the third embodiment has a configuration in which the purge medium in the combustion apparatus 2 employing the operation shutdown method of the second embodiment is an inert gas. The other configurations of the combustion apparatus 3 are the same as those of the combustion apparatus 2. Here, the configuration of the purge medium supply system 40B that supplies an inert gas as a purge medium will be mainly described.

[0117] As shown in FIG. 6, the combustion device 3 includes a combustor 10, a fuel supply system 20, an oxidizing agent supply system 30A, a purge medium supply system 40B, and a control device 50.

[0118] The combustor 10 and the fuel supply system 20 are as described in the first embodiment. The oxidizing agent supply system 30A is as described in the second embodiment.

[0119] The purge medium supply system 40B supplies a purge medium to the fuel supply pipe 22 to remove fuel remaining in the fuel ejection section 12. The purge medium supply system 40B includes a purge medium supply source 90, a purge medium supply pipe 91, and a flow rate adjustment section 92. The purge medium is an inert gas. Examples of the inert gas that can be used include nitrogen gas, argon gas, and helium gas. Among these inert gases, nitrogen gas has the advantage that it is inexpensive. Here, an example will be described in which nitrogen gas is used as the purge medium.

[0120] The purge medium supply source 90 supplies nitrogen gas to the fuel supply pipe 22 via a purge medium supply pipe 91. The purge medium supply source 90 is formed, for example, from a nitrogen cylinder that stores high-pressure nitrogen.

[0121] The purge medium supply pipe 91 supplies the purge medium to the fuel supply pipe 22 for supply to the fuel ejection part 12. One end of the purge medium supply pipe 91 is connected to the fuel supply pipe 22 between the flow rate adjustment part 23 and the fuel ejection part 12. The other end of the purge medium supply pipe 91 is connected to a purge medium supply source 90.

[0122] The flow rate adjusting unit 92 adjusts the flow rate of the nitrogen gas supplied to the fuel supply pipe 22. The flow rate adjusting unit 92 is disposed in the purge medium supply pipe 91. The flow rate adjusting unit 92 is formed of, for example, a flow rate adjustment valve.

[0123] The control device 50 controls, for example, the flow rate adjustment unit 23 of the fuel supply system 20, the oxidant supply source 31 and flow rate adjustment unit 33 of the oxidant supply system 30A, and the flow rate adjustment unit 92 of the purge medium supply system 40B, based on an operation command signal input from the outside, a signal from the flame detection unit 14, etc.

[0124] The configuration of the control device 50 is as shown in Fig. 2. The purge medium supply storage unit 71 stores, for example, data for controlling the flow rate adjustment unit 92 when supplying the purge medium. The purge medium supply storage unit 71 also stores, for example, various programs and various data for executing control for stopping the operation of the combustion device 3.

[0125] When performing the operation shutdown process, the purge medium supply determination unit 76 controls the flow rate adjustment unit 92 and the like based on the data stored in the memory unit 70. The flame extinction determination unit 77 is as described in the first embodiment.

[0126] The output unit 61 outputs, for example, a control signal from the purge medium supply determination unit 76 to the flow rate adjustment unit 92.

[0127] Next, the operation of the combustion device 3 will be described.

[0128] First, the action of the combustion device 3 during steady operation will be described.

[0129] During steady operation, fuel is supplied to the fuel ejection portion 12 through the fuel supply pipe 22. The oxidizer is supplied to the oxidizer ejection portion 13 through the oxidizer supply pipe 32. Then, in the combustion chamber 11, the fuel ejected from the fuel ejection portion 12 and the oxidizer ejected from the oxidizer ejection portion 13 combust to form a flame. Note that during steady operation, the flow rate adjustment portion 92 of the purge medium supply pipe 91 is closed.

[0130] Next, the action of the combustion device 3 when the operation is stopped will be described.

[0131] Here, the following mainly describes the operation of the combustion device 1 when the operation is stopped in the first embodiment. Note that the time charts and flow charts for explaining the method for stopping the operation of the combustion device 3 are the same as those for explaining the method for stopping the operation of the combustion device 1, and therefore will be described with reference to Figs. 3 and 4.

[0132] When the purge medium supply determining unit 76 determines in step S10 that an operation stop signal has been input (Yes in step S10), the purge medium supply determining unit 76 executes a process for supplying the purge medium to the fuel supply pipe 22 via the purge medium supply pipe 91 (step S11). Here, in FIG. 3, time t1 is the time when the supply of the purge medium to the fuel supply pipe 22 via the purge medium supply pipe 91 is started.

[0133] In step S11, the purge medium supply determination unit 76 refers to the purge medium supply storage unit 71 and outputs a control signal for controlling the opening degree of the flow rate adjustment unit 92 to the output unit 61. Then, the output unit 61 outputs the control signal to the flow rate adjustment unit 92.

[0134] 3, the supply of the purge medium is started from time t1, and at time t2, a specified flow rate of the purge medium is supplied to the fuel supply pipe 22. The purge medium is mixed with the fuel in the fuel supply pipe 22 and supplied to the fuel ejection part 12. That is, the fuel diluted by the purge medium is ejected from the fuel ejection part 12.

[0135] The specified flow rate of the purge medium is set to a flow rate that can extinguish the flame formed in the combustion chamber 11. Although an air-fuel mixture is formed by mixing nitrogen gas with fuel, this mixture does not contain an oxidizer and therefore does not form a flammable mixture.

[0136] During the purging process, it is preferable that the surrounding air does not enter the inside through the nozzle holes of the fuel ejection part 12. The specified flow rate of the purge medium may be set, for example, so that the flow velocity of the mixture ejected from the fuel ejection part 12 is greater than the maximum combustion velocity of the fuel in the air.

[0137] In step S14, the purge medium supply determining unit 76 determines whether or not a predetermined time has elapsed after the fuel supply was shut off (step S14).

[0138] When it is determined in step S14 that the predetermined time has elapsed (Yes in step S14), the purge medium supply determining unit 76 executes a process for stopping the supply of the purge medium to the fuel supply pipe 22 (step S15). In step S15, the purge medium supply determining unit 76 outputs a control signal for closing the flow rate adjusting unit 92 to the output unit 61. At this time, the purge medium supply determining unit 76 outputs a control signal for stopping the supply of air from the oxidizing agent supply source 31 to the output unit 61. Then, the output unit 61 outputs the control signal to the flow rate adjusting unit 92.

[0139] 3, even after the fuel supply is cut off, a specified flow rate of the purge medium is supplied to the fuel supply pipe 22 and the fuel ejection part 12 via the purge medium supply pipe 91. Then, when a predetermined time has elapsed after the fuel supply is cut off, the supply of the purge medium is stopped.

[0140] As described above, in the method for shutting down the operation of the combustion apparatus 3 according to the third embodiment, a purge medium can be supplied to the fuel supply pipe 22 to extinguish the flame before the supply of fuel is cut off.

[0141] Even after the flame is extinguished, the same specified flow rate of purge medium as that used for extinguishing the flame is supplied to the fuel supply pipe 22 and the fuel ejection part 12, so that a flammable mixture is not formed in the fuel supply pipe 22 and the fuel ejection part 12 even if fuel is being supplied.

[0142] In addition, even after the fuel supply is cut off, the same specified flow rate of purge medium as used for extinguishing is supplied to the fuel supply pipe 22 and the fuel ejection part 12, so that even if fuel remains, a flammable mixture is not formed in the fuel supply pipe 22 and the fuel ejection part 12.

[0143] Furthermore, by continuing to supply the purge medium even after the flame is extinguished, for example, the combustion chamber 11, the fuel ejection part 12, and the oxidizer ejection part 13 in the combustor 10 are cooled. As a result, no high-temperature part that can become an ignition source is generated in the components of the combustor 10, so that even if air enters the inside through the ejection hole of the fuel ejection part 12 and a flammable mixture is formed, it will not ignite.

[0144] In this way, according to the method for shutting down the operation of the combustion apparatus 3 of the third embodiment, the remaining fuel is not ignited during the purging process, and the operation shut down process can be executed safely.

[0145] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0146] 1, 2, 3... Combustion device, 10... Combustor, 11... Combustion chamber, 12... Fuel ejection section, 13... Oxidizer ejection section, 14... Flame detection section, 20... Fuel supply system, 21... Fuel supply source, 22... Fuel supply pipe, 22a, 41a... Connection section, 23, 33, 36, 38, 43, 81, 92... Flow rate adjustment section, 30, 30A... Oxidizer supply system, 31... Oxidizer supply source, 32... Oxidizer supply pipe, 34... Heat exchanger Exchanger, 35...oxidizer supply branch pipe, 37...EGR piping, 40, 40A, 40B...purge medium supply system, 41, 80, 91...purge medium supply pipes, 42...purge medium pressure delivery section, 50...control device, 60...input section, 61...output section, 70...memory section, 71...purge medium supply memory section, 75...calculation section, 76...purge medium supply determination section, 77...flame extinction determination section, 90...purge medium supply source.

Claims

1. a combustion chamber for combusting a fuel and an oxidizer; a fuel ejection portion that ejects fuel into the combustion chamber; An oxidizer ejection portion that ejects an oxidizer into the combustion chamber; a fuel supply pipe for supplying fuel to the fuel ejection portion; an oxidant supply pipe for supplying an oxidant to the oxidant jetting portion; a purge medium supply pipe that supplies a purge medium to be supplied to the fuel injection portion to the fuel supply pipe; A method for shutting down a combustion apparatus comprising: In a state where a flame is formed, the purge medium is supplied from the purge medium supply pipe to the fuel supply pipe to extinguish the flame; After the flame is extinguished, the supply of fuel to the fuel supply pipe is cut off while the supply of the purge medium to the fuel supply pipe is continued; A method for shutting down a combustion apparatus, comprising the steps of: continuing to supply the purging medium to the fuel supply pipe for a predetermined time after the supply of fuel is cut off.

2. The purge medium is a gas in the combustion chamber, 2. A method for shutting down an operation of a combustion apparatus according to claim 1, wherein the gas is introduced from one end of the purge medium supply pipe, and the gas is supplied to the fuel supply pipe from the other end of the purge medium supply pipe.

3. 3. The method for shutting down a combustion apparatus according to claim 2, wherein a flow rate of the gas supplied to the fuel supply pipe is set so that a fuel concentration in a mixture formed by mixing the gas and the fuel in the fuel supply pipe is below a lower explosion limit.

4. 3. The method for stopping operation of a combustion device according to claim 2, wherein a flow rate of the gas supplied to the fuel supply pipe is set so that a flow velocity of the mixture formed by mixing the gas and the fuel in the fuel supply pipe when ejected from the fuel ejection portion is greater than a combustion velocity of the mixture.

5. 5. The method for shutting down an operation of a combustion apparatus according to claim 2, wherein the combustion apparatus is provided with a heat exchanger for exchanging heat between the gas flowing through the purge medium supply pipe and the oxidizer flowing through the oxidizer supply pipe.

6. The purge medium is air; The air is introduced from one end of the purge medium supply pipe, and the air is supplied from the other end of the purge medium supply pipe to the fuel supply pipe; 2. The method for shutting down a combustion apparatus according to claim 1, wherein a flow rate of the air supplied to the fuel supply pipe is set so that a fuel concentration in a mixture formed by mixing the air and fuel in the fuel supply pipe is below a lower explosion limit.

7. The purge medium is air; The air is introduced from one end of the purge medium supply pipe, and the air is supplied from the other end of the purge medium supply pipe to the fuel supply pipe; 2. The method for shutting down a combustion apparatus according to claim 1, wherein a flow rate of the air supplied to the fuel supply pipe is set so that a flow velocity of the mixture formed by mixing the air and fuel in the fuel supply pipe when ejected from the fuel ejection portion is greater than a combustion velocity of the mixture.

8. 8. The method for shutting down an operation of a combustion apparatus according to claim 6, wherein one end of the purge medium supply pipe is connected to the oxidizer supply pipe, and the air is introduced from the oxidizer supply pipe.

9. The purge medium is an inert gas; The inert gas is introduced from one end of the purge medium supply pipe, and the inert gas is supplied to the fuel supply pipe from the other end of the purge medium supply pipe; 2. The method for shutting down a combustion apparatus according to claim 1, wherein a flow rate of the inert gas supplied to the fuel supply pipe is set so that a flow velocity of the mixture formed by mixing the inert gas and the fuel in the fuel supply pipe when ejected from the fuel ejection portion is greater than a maximum combustion velocity of the fuel in air.

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