Shock Wave Generator

Abstract

To provide a shock wave generation device capable of determining the combustion state of fuel.SOLUTION: The shock wave generation device includes a combustion device in which a gas passage is provided in a range from the base end to the front end for combustion gas to flow therein, and at the front end of which an opening part is provided, a combustible gas supply device for supplying combustible gas from the base end of the combustion device to the inside, an ignition device for igniting the combustible gas supplied to the combustion device, a flame generation timing detection sensor for detecting a generation timing for frames due to the combustion of the combustible gas, and a determination device for determining the self-ignition of the combustible gas before the ignition by the ignition device on the basis of the detection result of the frame generation timing detection sensor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a shock wave generating device for generating shock waves by detonation. [Background technology]

[0002] For example, in waste incinerators, integrated coal gasification combined cycle (IGCC) plants, and power generation boilers, dust contained in the exhaust gas adheres to the inner walls of the furnace and the outer surfaces of the heat transfer tubes. Dust adhering to the inner walls of the furnace and the outer surfaces of the heat transfer tubes reduces the heat transfer coefficient, worsening the heat recovery efficiency, and acts as resistance to the flow of exhaust gas, reducing the performance of the furnace. For this reason, it is necessary to periodically remove dust adhering to the inner walls of the furnace and the outer surfaces of the heat transfer tubes using a dust removal device.

[0003] The dust removal device has a shock wave generating device. The shock wave generating device burns fuel to generate shock waves by detonation in which the flame propagation speed exceeds the speed of sound. The dust removal device removes dust by the shock waves generated by the shock wave generating device. Such a conventional shock wave generating device is described in the following patent document. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 60-205120 [Patent Document 2] JP 2002-106826 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional shock wave generating devices ignite a mixture of fuel and oxidizer, and generate a shock wave by detonation as the mixture burns. In this case, depending on the type of combustion, a detonation wave may not be generated, and a deflagration wave may occur, which may result in, for example, dust not being properly removed. In addition, before the mixture is ignited, the mixture may self-ignite and cause a backfire. Therefore, the shock wave generating device needs to determine whether a detonation is occurring properly.

[0006] The present disclosure is devised to solve the above-mentioned problems, and aims to provide a shock wave generating device capable of determining the combustion state of fuel. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the shock wave generating device of the present disclosure includes a combustion device having a gas passage through which combustion gas flows from a base end to a tip end and an opening at the tip end, a combustible gas supply device that supplies combustible gas from the base end of the combustion device to the inside, an ignition device that ignites the combustible gas supplied to the combustion device, a flame generation timing detection sensor that detects the timing of flame generation due to combustion of the combustible gas, and a determination device that determines self-ignition of the combustible gas before ignition by the ignition device based on the detection result of the flame generation timing detection sensor. Effect of the Invention

[0008] According to the shock wave generating device of the present disclosure, the combustion state of fuel can be determined. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a shock wave generating device according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the mounting structure of the optical sensor. [Diagram 3] FIG. 3 is a cross-sectional view showing a modified example of the mounting structure of the optical sensor. [Figure 4]FIG. 4 is a time chart for explaining a method for detecting detonation, deflagration, and flashback. [Diagram 5] FIG. 5 is a flowchart showing a method for determining the combustion state of fuel by the shock wave generating device. [Figure 6] FIG. 6 is a schematic diagram for explaining the strength of detonation in the shock wave generating device of the second embodiment. [Figure 7] FIG. 7 is a schematic diagram showing the configuration of a shock wave generating device according to the third embodiment. [Figure 8] FIG. 8 is a time chart for explaining a method for detecting detonation, deflagration, and flashback. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes a configuration in which each embodiment is combined. In addition, the components in the embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range.

[0011] [First embodiment] <Shock wave generator> FIG. 1 is a schematic diagram showing the configuration of a shock wave generating device according to a first embodiment.

[0012] As shown in FIG. 1, the shock wave generating device 10 of the first embodiment is applied to a dust removing device that removes dust attached to the inner wall surface and the outer surface of a heat transfer tube of a furnace such as a waste incinerator, a coal gasification combined cycle power generation facility, or a power generation boiler (hereinafter referred to as a boiler). The furnace is composed of a wall portion that surrounds the combustion field of the boiler, and the dust removing device can remove dust attached to the inner wall surface of the wall portion that is continuous with the upper and lower parts of the furnace. The dust removing device supplies combustible gas into the furnace through a pipe that communicates with the inside of the furnace, and generates a shock wave S by detonation by igniting the combustible gas. That is, when the combustible gas burns, a detonation wave in which the flame and the shock wave are integrated propagates, and when the combustible gas is gone, it propagates as a shock wave. The dust removing device blows off and removes the attached dust by applying the shock wave S by detonation to the inner wall of the furnace and the outer surface of the heat transfer tube.

[0013] The shock wave generating device 10 is provided in the dust removal device, and generates a shock wave S by detonation caused by burning fuel when the dust removal device operates while the boiler is stopped.

[0014] The shock wave generating device 10 includes a combustion device 11, a combustible gas supply device 12, an ignition device 13, a flame generation timing detection sensor 14, a control device (determination device) 15, and an alarm device 16.

[0015] The combustion device 11 has a gas passage 21 through which combustion gas flows from the base end to the tip end. The combustion device 11 has a detonator 22 and a combustor 23. The gas passage 21 is composed of a first passage 24 provided inside the detonator 22 and a second passage 25 provided inside the combustor 23.

[0016] The detonation tube 22 has a cylindrical shape, a base end 22a is closed, and a tip 22b is open. The detonation tube 22 has a first passage 24 of a predetermined length provided therein. The detonation tube 22 has a base end 22a connected to the combustible gas supply device 12. The combustor 23 has a cylindrical shape, a base end 23a is connected to the tip 22b of the detonation tube 22 and communicates with it, and the tip 23b is open and provides an opening 23c. The gas passage 21 of the detonation tube 22 and the second passage 25 of the combustor 23 are concentric. However, the gas passage 21 of the detonation tube 22 and the second passage 25 of the combustor 23 do not have to be concentric and may have different shapes. The combustor 23 has a second passage 25 of a predetermined length provided therein. The second passage 25 of the combustor 23 has a larger diameter than the first passage 24 of the detonation tube 22. The second passage 25 of the combustor 23 has the same diameter from the base end 23a to the tip 22b, but the tip 22b may have a larger diameter than the base end 23a. The opening 23c of the tip 23b of the combustor 23 communicates with an internal space 103 defined by a furnace wall 102 of the furnace 101.

[0017] The combustible gas supplying device 12 has a fuel supplying unit 31 and an oxidizing agent supplying unit 41. The fuel supplying unit 31 supplies fuel F. The oxidizing agent supplying unit 41 supplies oxygen or air as an oxidizing agent A. The combustible gas supplying device 12 supplies a mixture of the fuel F supplied by the fuel supplying unit 31 and the oxidizing agent A supplied by the oxidizing agent supplying unit 41 as combustible gas M from the base end of the combustion device 11 to the inside.

[0018] The fuel supply unit 31 has a fuel supply path 32, a fuel cylinder 33, a pressure reducing valve 34, a mass flow controller 35, a safety device 36, a fuel supply valve 37, and a check valve 38. The fuel supply path 32 has the fuel cylinder 33 connected to its upstream end, and is provided with the pressure reducing valve 34, the mass flow controller 35, the safety device 36, the fuel supply valve 37, and the check valve 38 toward the downstream side. The fuel cylinder 33 stores fuel F. The pressure reducing valve 34 reduces the pressure of the fuel F in the fuel cylinder 33 and adjusts the pressure of the fuel F to be supplied. The mass flow controller 35 measures the mass flow rate of the fuel F, compares the measured mass flow rate of the fuel F with a preset set value of the fuel F, and adjusts the opening of the flow control valve so that the mass flow rate of the fuel F becomes the set value. The safety device 36 prevents flashback. The fuel supply valve 37 is an on-off valve that supplies the fuel F when open and stops the supply of the fuel F when closed. The check valve 38 prevents the fuel F and the flammable gas M from flowing back upstream.

[0019] The oxidizer supply unit 41 has an oxidizer supply path 42, an oxidizer cylinder 43, a pressure reducing valve 44, a mass flow controller 45, a safety device 46, an oxidizer supply valve 47, and a check valve 48. The oxidizer supply path 42 has an oxidizer cylinder 43 connected to its upstream end, and is provided with a pressure reducing valve 44, a mass flow controller 45, a safety device 46, an oxidizer supply valve 47, and a check valve 48 toward its downstream side. The oxidizer cylinder 43 stores oxidizer A. The pressure reducing valve 44 reduces the pressure of the oxidizer A in the oxidizer cylinder 43, and adjusts the pressure of the oxidizer A to be supplied. The mass flow controller 45 measures the mass flow rate of the oxidizer A, compares the measured mass flow rate of the oxidizer A with a preset set value of the oxidizer A, and adjusts the opening of the flow control valve so that the mass flow rate of the oxidizer A becomes the set value. The safety device 46 prevents backfire. The oxidant supply valve 47 is an on-off valve that supplies the oxidant A when open and stops the supply of the oxidant A when closed. The check valve 48 prevents the backflow of the oxidant A and the flammable gas M to the upstream side.

[0020] The downstream ends of the fuel supply path 32 and the oxidizer supply path 42 are connected to the upstream end of the combustible gas supply path 52 via a cross joint 51, and the downstream end of the combustible gas supply path 52 is connected to the base end 22a of the detonator 22. The upstream end of the purge gas path 53 is connected to a blower 54, and the downstream end is connected to the cross joint 51. The purge gas path 53 is provided with a purge gas supply valve 55. The cross joint 51 communicates the fuel supply path 32, the oxidizer supply path 42, the combustible gas supply path 52, and the purge gas path 53. The blower 54 supplies a purge gas (e.g., air, an inert gas, etc.) P to the combustible gas supply path 52. The purge gas supply valve 55 is an open / close valve that supplies the purge gas P when opened and stops the supply of the purge gas P when closed.

[0021] The ignition device 13 ignites the combustible gas M supplied to the detonation tube 22 in the combustion device 11. The ignition device 13 is provided at a base end 22a of the detonation tube 22.

[0022] The flame occurrence timing detection sensor 14 detects the occurrence timing of a flame C due to combustion of the combustible gas M. The flame occurrence timing detection sensor 14 is provided at the base end 23a of the combustor 23 in the combustion device 11. The flame occurrence timing detection sensor 14 is disposed facing the opening 23c from the base end 23a of the combustor 23, thereby having a sensor area 14a of a predetermined angle.

[0023] The flame occurrence time detection sensor 14 is preferably an optical sensor that detects light emitted from the flame C generated in the combustor 23. As the optical sensor, an ultraviolet light detection sensor is preferable. A flame radiates electromagnetic waves with wavelengths of infrared light (IR), visible light, and ultraviolet light (UV). However, since infrared light and visible light are emitted from sources other than the flame C, an ultraviolet light detection sensor is used to insensitively detect infrared light and visible light and detect ultraviolet light to detect a signal only from the flame C. In particular, by selectively detecting ultraviolet light with a short wavelength (for example, wavelengths of 100 nm to 315 nm that are difficult to reach the ground as a component of sunlight due to absorption by the atmosphere, particularly the solar blind region of 100 nm to 280 nm that hardly reaches the ground), erroneous detection of extrasolar light is prevented.

[0024] However, the optical sensor is not limited to the ultraviolet light detection sensor, and for example, a photodiode or a phototube may be used as the optical sensor.

[0025] The control device 15 is connected to the ignition device 13, the flame occurrence timing detection sensor 14, the mass flow controller 35, the fuel supply valve 37, the mass flow controller 45, the oxidizer supply valve 47, and the purge gas supply valve 55.

[0026] The control device 15 can control the timing of ignition of the combustible gas M by the ignition device 13. The detection result of the flame generation timing detection sensor 14 is input to the control device 15. The control device 15 can adjust and control the mass flow controller 35 and the mass flow controller 45. The control device 15 can control the opening and closing of the fuel supply valve 37, the oxidizer supply valve 47, and the purge gas supply valve 55.

[0027] The control device 15 also functions as a determination device. That is, the control device 15 determines whether the combustible gas M has spontaneously ignited before ignition by the ignition device 13 based on the detection result of the flame occurrence timing detection sensor 14. The control device 15 also determines whether the combustible gas M has spontaneously ignited before ignition by the ignition device 13 based on the propagation speed of the flame C detected by the flame occurrence timing detection sensor 14.

[0028] Then, when the control device 15 determines the spontaneous ignition of the combustible gas M, it controls the combustible gas supply device 12 to stop the supply of the combustible gas M to the combustion device 11. That is, the control device 15 closes the fuel supply valve 37 and the oxidizing agent supply valve 47. Furthermore, when the control device 15 determines the spontaneous ignition of the combustible gas M, it supplies the purge gas P into the combustion device 11. That is, the control device 15 closes the fuel supply valve 37 and the oxidizing agent supply valve 47, and then opens the purge gas supply valve 55.

[0029] The control device 15 is connected to an alarm device 16. The control device 15 is capable of controlling the operation of the alarm device 16. The control device 15 activates the alarm device 16 when it determines that the combustible gas M has spontaneously ignited or deflagrated.

[0030] Here, the control device 15 is a controller, and is realized by, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) executing various programs stored in a storage unit using a RAM as a working area.

[0031] <Optical sensor mounting structure> FIG. 2 is a cross-sectional view showing the mounting structure of the optical sensor.

[0032] As shown in Fig. 2, the combustor 23 is provided with an optical window 62 on a wall 61 on the base end 23a side. An optical sensor as the flame onset timing detection sensor 14 is disposed on the outer side of the wall 61 of the combustor 23 so as to cover the optical window 62. The flame onset timing detection sensor 14 has a sensor area 14a of a predetermined angle set through the optical window 62. The flame onset timing detection sensor 14 detects light emitted from the flame C through the optical window 62. The optical window 62 may be transparent and have a filtering performance for extracting only light of a specific wavelength (e.g., ultraviolet light). The optical window 62 may be provided with a mechanism for ejecting purge gas against the inner surface to ensure visibility and cooling.

[0033] The mounting structure of the optical sensor is not limited to the above-mentioned one, and Fig. 3 is a cross-sectional view showing a modified example of the mounting structure of the optical sensor.

[0034] As shown in Fig. 3, the combustor 23 is provided with an optical window 62 in a wall portion 61 on the base end 23a side. An optical sensor serving as the flame onset timing detection sensor 14 is disposed at a predetermined position spaced apart from the combustor 23. An optical fiber 63 is provided between the flame onset timing detection sensor 14 and the optical window 62. One end of the optical fiber 63 is connected to the flame onset timing detection sensor 14, and the other end is attached by an attachment member 64 to the outside of the wall portion 61 of the combustor 23 so as to face the optical window 62. The flame onset timing detection sensor 14 has a sensor area 14a of a predetermined angle set via the optical fiber 63 and the optical window 62. The flame onset timing detection sensor 14 detects light emission from the flame C through the optical window 62 by the optical fiber 63.

[0035] <Detection methods for detonation, deflagration and flashback> FIG. 4 is a time chart for explaining a method for detecting detonation, deflagration, and flashback.

[0036] As shown in Fig. 1 and Fig. 4, the combustible gas supplying device 12 supplies the combustible gas M, which is a mixture of fuel and oxidizer, to the detonation tube 22 by the fuel supplying section 31 and the oxidizer supplying section 41 to fill the detonation tube 22. Then, at time t2, the ignition device 13 is activated to ignite the combustible gas M in the detonation tube 22. Then, the combustible gas M is ignited while flowing through the first passage 24 of the detonation tube 22, and burns so that the flame C spreads from the base end 22a to the tip 22b. Then, when the flame C of the detonation tube 22 reaches the combustor 23, the flame C spreads from the base end 23a through the second passage 25 to the tip 23b, and a shock wave S is generated by detonation.

[0037] The control device 15 judges detonation, deflagration, and flashback (autoignition) based on the occurrence timing (propagation speed) of the flame C detected by the flame occurrence timing detection sensor 14. The flame occurrence timing detection sensor 14 is an optical sensor that detects the flame C (e.g., ultraviolet light). The flame occurrence timing detection sensor 14 turns on a pulse when the flame C occurs, and turns off a pulse when the flame C is extinguished. Therefore, the control device 15 calculates a pulse length τd, which is the time during which the flame C occurs, from the time when the flame occurs (pulse ON) to the time when the flame is extinguished (pulse OFF), detected by the flame occurrence timing detection sensor 14. The pulse length τd is inversely proportional to the propagation speed of the flame C. The control device 15 judges the combustion state of the fuel (combustible gas M) based on the pulse length τd (propagation speed of the flame C) during the occurrence period of the flame C.

[0038] When fuel burns, it becomes a deflagration or a detonation depending on the propagation speed of the flame C. When the propagation speed of the flame C is equal to or less than the speed of sound, it becomes a deflagration, and when the propagation speed of the flame C exceeds the speed of sound, it becomes a detonation and a shock wave S is generated. When it becomes a detonation, a shock wave S is generated. Here, a threshold value τt according to the propagation speed of the flame C is set between the deflagration and the detonation. The threshold value τt according to the propagation speed between the deflagration and the detonation is, for example, a pulse length according to a propagation speed of 1000 m / s. In other words, when the calculated pulse length τd is equal to or less than the threshold value τt, it is a detonation, and when the pulse length τd (propagation speed of the flame C) exceeds the threshold value τt, it is a deflagration. In general, the propagation speed of the shock wave S due to the detonation (propagation speed of the flame C) is 1000 m / s or more, so the pulse length τd becomes shorter.

[0039] Therefore, when the pulse length τd is equal to or less than the threshold value τt, the control device 15 judges it as a detonation, and when the pulse length τd (the propagation speed of the flame C) exceeds the threshold value τt, the control device 15 judges it as a deflagration. In other words, when the pulse turns ON at time t3 and OFF at time t4, the pulse length τd is equal to or less than the threshold value τt, so the control device 15 judges it as a detonation. On the other hand, when the pulse turns ON at time t3 and OFF at time t6, the pulse length τd exceeds the threshold value τt, so the control device 15 judges it as a deflagration.

[0040] During the operation of the boiler, the combustible gas M filled in the combustor 23 may spontaneously ignite due to heat from the exhaust gas rising in the internal space 103 of the furnace 101. The control device 15 judges backfire due to spontaneous ignition based on the occurrence time of the flame C detected by the flame occurrence time detection sensor 14. That is, at time t2, the ignition device 13 is activated and the combustible gas M in the detonator 22 is ignited, and then the combustible gas M is ignited and a shock wave S is generated by detonation. However, when the combustible gas M filled in the combustor 23 spontaneously ignites, the flame occurrence time detection sensor 14 detects the flame C before the ignition device 13 is activated. When the ignition device 13 is activated at time t2 to ignite the combustible gas M, if a backfire (spontaneous ignition) occurs, the pulse is turned ON at time t1, which is the time Ta before time t2, and the pulse is turned OFF at time t5. When the pulse turns ON at time t1 before time t2 when the ignition device 13 is activated, the control device 15 determines that a flashback has occurred.

[0041] Then, when the control device 15 determines that a detonation has occurred, since the combustion device 11 is burning normally, the control device 15 operates the combustion device 11, the combustible gas supply device 12, and the ignition device 13 in the same manner at the next operating timing.

[0042] On the other hand, when the control device 15 determines that a deflagration has occurred, since the combustion device 11 is in an abnormal combustion state, the control device 15 operates the combustion device 11, the combustible gas supply device 12, and the ignition device 13 by different control at the next operation timing. That is, the control device 15 adjusts the mixture ratio of fuel and oxidizer in the combustible gas M generated by the combustible gas supply device 12, for example.

[0043] Furthermore, when the control device 15 determines that a flashback has occurred, since abnormal combustion is occurring in the combustion device 11, the control device 15 stops the supply of the combustible gas M to the combustion device 11 by the combustible gas supply device 12. Then, the control device 15 supplies the purge gas P to the combustion device 11 to suppress the progression of the flashback.

[0044] <Method for determining fuel combustion state> FIG. 5 is a flowchart showing a method for determining the combustion state of fuel by the shock wave generating device.

[0045] 1 and 5, in step S11, the control device 15 closes the purge gas supply valve 55 to stop the supply of purge gas P to the combustion device 11. In step S12, the control device 15 opens the fuel supply valve 37 to start the supply of fuel F, and opens the oxidizer supply valve 47 to start the supply of oxidizer A. Then, the combustible gas M, which is a mixture of the fuel F and the oxidizer A, is supplied to the detonator 22 of the combustion device 11.

[0046] In step S13, the control device 15 judges whether the flame occurrence timing detection sensor 14 has detected a pulse (ON) generated with the occurrence of a flame. Here, when the control device 15 judges that the flame occurrence timing detection sensor 14 has detected a pulse (ON) (Yes), in step S14, the control device 15 judges that a backfire has occurred, and in step S15, judges that the combustion device 11 has abnormal combustion. That is, the control device 15 judges that the abnormal combustion has occurred with a backfire because the flame occurrence timing detection sensor 14 detected the flame C generated in the combustor 23 even before the ignition device 13 was activated. Then, in step S16, the alarm device 16 is activated. In step S17, the supply of the combustible gas M to the combustion device 11 is stopped, and in step S18, the purge gas P is supplied to the combustion device 11.

[0047] On the other hand, if the control device 15 determines in step S13 that the flame generation timing detection sensor 14 has not detected a pulse (ON) (No), the process proceeds to step S19. In step S19, the control device 15 determines whether a preset predetermined elapsed time has elapsed since the combustible gas M was supplied to the detonator 22. Here, the elapsed time refers to the time until a predetermined amount of combustible gas M is filled inside the detonator 22 and the combustor 23 in the combustion device 11. If the control device 15 determines that the predetermined elapsed time has not elapsed (No), the process returns to step S13.

[0048] On the other hand, when the control device 15 determines that the predetermined time has elapsed (Yes), in step S20, the control device 15 closes the fuel supply valve 37 to stop the supply of the fuel F, and closes the oxidizer supply valve 47 to stop the supply of the oxidizer A. Then, the supply of the combustible gas M to the detonator 22 of the combustion device 11 is stopped. Then, in step S21, the control device 15 operates the ignition device 13 to ignite the combustible gas M filled in the detonator 22. Then, the combustible gas M is ignited while flowing through the first passage 24 of the detonator 22, and the flame C burns so as to spread from the base end 22a to the tip 22b. Then, when the flame C of the detonator 22 reaches the combustor 23, the flame C burns so as to spread from the base end 23a through the second passage 25 to the tip 23b.

[0049] In step S22, the control device 15 judges whether or not the flame occurrence timing detection sensor 14 has detected a pulse (ON) that is generated in association with the occurrence of a flame. Here, when the control device 15 judges that the flame occurrence timing detection sensor 14 has not detected a pulse (ON) (No), in step S31, the control device 15 judges whether or not a preset predetermined waiting time has elapsed since the ignition device 13 was activated. Here, when the control device 15 judges that the waiting time has not elapsed (No), the control device 15 waits as is. However, when the control device 15 judges that the waiting time has elapsed (Yes), in step S32, the control device 15 presumes that the ignition device 13 has failed to ignite the combustible gas M, and in step S33, the control device 15 activates the alarm device 16.

[0050] On the other hand, when the control device 15 determines that the flame occurrence timing detection sensor 14 has detected a pulse (ON) (Yes), the control device 15 determines in step S23 whether the detected pulse length τd is equal to or less than the threshold value τt. Here, when the control device 15 determines that the detected pulse length τd is not equal to or less than the threshold value τt (No), the control device 15 determines in step S24 that a deflagration has occurred, and determines in step S25 that there is abnormal combustion in the combustion device 11. Then, in step S26, the alarm device 16 is activated. In step S27, the mixture ratio of the fuel F and the oxidizer A in the combustible gas M supplied to the combustion device 11 is adjusted.

[0051] On the other hand, if in step S23 the control device 15 determines that the detected pulse length τd is equal to or less than the threshold value τt (Yes), in step S28 the control device 15 determines that a detonation has occurred, and in step S29 determines that the combustion device 11 is burning normally.

[0052] [Second embodiment] Fig. 6 is a schematic diagram for explaining the strength of the detonation in the shock wave generating device of the second embodiment. The basic configuration of the second embodiment is the same as that of the first embodiment described above, and will be explained using Fig. 1. The same reference numerals are given to members having the same functions as those of the first embodiment described above, and detailed explanations will be omitted.

[0053] As shown in FIG. 1, the shock wave generating device 10 includes a combustion device 11, a combustible gas supply device 12, an ignition device 13, a flame generation timing detection sensor 14, a control device (determination device) 15, and an alarm device 16.

[0054] The control device 15 functions as a determination device and determines whether a detonation, deflagration, or flashback (autoignition) occurs based on the detection result of the flame occurrence timing detection sensor 14. When the control device 15 determines that a detonation has occurred based on the detection result of the flame occurrence timing detection sensor 14, it estimates the intensity of the detonation wave based on the propagation speed of the flame.

[0055] The intensity of the detonation is estimated according to the generation time of the flame C generated in the combustor 23, that is, the pulse length τd from when the flame generation timing detection sensor 14 detects the flame C and the pulse turns ON to when the pulse turns OFF. That is, the intensity of the flame detonation changes according to the filling amount of the combustible gas M supplied to the combustor 23. Therefore, it can be estimated that the intensity of the detonation is higher when the pulse length τd is equal to or less than the threshold value τt and the longer the pulse length τd is.

[0056] As shown in FIG. 6, when the pulse length τd of the shock wave S (flame) is defined as being equal to or less than the threshold value τt, the maximum shock wave with the highest intensity is when the pulse length τd=threshold value τt. For example, when the pulse length τd is a pulse length τd1 that is shorter than 1 / 2 the threshold value τt, the first shock wave has a low intensity. On the other hand, when the pulse length τd is a pulse length τd2 that is longer than 1 / 2 the threshold value τt, the second shock wave has a high intensity. The threshold value τt is set with a margin of error in mind.

[0057] 1, the control device 15 controls the combustible gas supply device 12 based on the intensity of the detonation (shock wave S) estimated from the pulse length τd of the shock wave S. For example, the control device 15 increases or decreases the amount of combustible gas M charged into the combustion device 11, or adjusts the mixture ratio of the fuel F and the oxidizer A in the combustible gas M, based on the intensity of the detonation (shock wave S). Therefore, the intensity of the shock wave S can be set to an optimal intensity according to the volume of the furnace 101.

[0058] [Third embodiment] 7 is a schematic diagram showing the configuration of a shock wave generating device according to a third embodiment. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals and detailed description thereof will be omitted.

[0059] 7, the shock wave generating device 10A includes a combustion device 11, a combustible gas supply device 12, an ignition device 13, flame generation timing detection sensors 14A and 14B, a control device (determination device) 15, and an alarm device 16. The combustion device 11, the combustible gas supply device 12, the ignition device 13, the control device 15, and the alarm device 16 have substantially the same configurations as those in the first embodiment.

[0060] The first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B detect the occurrence timing of a flame C due to the combustion of the combustible gas M. The flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B are arranged at intervals in the gas flow direction of the combustor 23 in the combustion device 11 (two in this embodiment). The flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B are arranged facing a direction intersecting the flow direction of the combustible gas M or the flame C (shock wave S) in the second passage 25 of the combustor 23. The flame occurrence timing detection sensor 14A is arranged on the upstream side of the second passage 25, and the second flame occurrence timing detection sensor 14B is arranged on the upstream side of the second passage 25. The first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B detect a flame at two points in different gas flow directions in the second passage 25 of the combustor 23. The first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B are optical sensors that detect light emission from the flame C generated in the combustor 23, and the detection method is the same as in the first embodiment.

[0061] FIG. 8 is a time chart for explaining a method for detecting detonation, deflagration, and flashback.

[0062] As shown in Fig. 7 and Fig. 8, the combustible gas supplying device 12 supplies the combustible gas M, which is a mixture of fuel and oxidizer, to the detonation tube 22 by the fuel supplying section 31 and the oxidizer supplying section 41 to fill the detonation tube 22. Then, at time t2, the ignition device 13 is activated to ignite the combustible gas M in the detonation tube 22. Then, the combustible gas M is ignited while flowing through the first passage 24 of the detonation tube 22, and burns so that the flame C spreads from the base end 22a to the tip 22b. Then, when the flame C of the detonation tube 22 reaches the combustor 23, the flame C spreads from the base end 23a through the second passage 25 to the tip 23b, and a shock wave S is generated by detonation.

[0063] The control device 15 judges detonation, deflagration, and flashback (autoignition) based on the occurrence timing (propagation speed) of the flame C detected by the first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B. The first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B are optical sensors that detect the flame C (e.g., ultraviolet light). The first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B turn on the pulse when the flame C occurs, and turn off the pulse when the flame C disappears. When the fuel burns, it becomes a deflagration or a detonation depending on the propagation speed of the flame C. When the propagation speed of the flame C is equal to or less than the speed of sound, it becomes a deflagration, and when the propagation speed of the flame C exceeds the speed of sound, it becomes a detonation and a shock wave S is generated.

[0064] The first flame occurrence timing detection sensor 14A and the second flame occurrence timing detection sensor 14B are disposed at a distance L apart in the gas flow direction of the second passage 25. Therefore, a time difference Δt occurs between the time when the flame is detected (pulse ON) by the first flame occurrence timing detection sensor 14A and the time when the flame is detected (pulse ON) by the second flame occurrence timing detection sensor 14B. The time difference Δt is inversely proportional to the propagation speed of the flame C. The control device 15 determines the combustion state of the fuel (combustible gas M) based on the time difference Δt of the shock wave S (propagation speed of the flame C).

[0065] Here, a threshold value Vt of the propagation speed of the flame C is set between the deflagration and the detonation. The threshold value Vt of the propagation speed between the deflagration and the detonation is, for example, a propagation speed of 1000 m / s. In other words, when the propagation speed L / Δt calculated from the distance L and the calculated time difference Δt is equal to or greater than the threshold value Vt, it is a detonation, and when the propagation speed L / Δt is less than the threshold value Vt, it is a deflagration.

[0066] Therefore, when the propagation speed L / Δt is equal to or greater than the threshold value Vt, the control device 15 judges it to be a detonation, and when the propagation speed L / Δt is less than the threshold value Vt, the control device 15 judges it to be a deflagration. That is, when the pulse of the first flame occurrence time detection sensor 14A turns ON at time t3 and the pulse of the second flame occurrence time detection sensor 14B turns ON at time t4, the time difference Δt1 is short and the propagation speed L / Δt1 is equal to or greater than the threshold value Vt, so the control device 15 judges it to be a detonation. On the other hand, when the pulse of the first flame occurrence time detection sensor 14A turns ON at time t3 and the pulse of the second flame occurrence time detection sensor 14B turns ON at time t5, the time difference Δt2 is long and the propagation speed L / Δt2 is less than the threshold value Vt, so the control device 15 judges it to be a deflagration.

[0067] During operation of the boiler, the combustible gas M filled in the combustor 23 may spontaneously ignite due to heat from the exhaust gas rising in the internal space 103 of the furnace 101. The control device 15 determines backfire due to spontaneous ignition based on the occurrence timing of the flame C detected by the first flame occurrence timing detection sensor 14A or the second flame occurrence timing detection sensor 14B. That is, at time t2, the ignition device 13 is activated and ignites the combustible gas M in the detonator 22, and then the combustible gas M is ignited and a shock wave S is generated by detonation. However, when the combustible gas M filled in the combustor 23 spontaneously ignites, the flame occurrence timing detection sensors 14, 14B detect the flame C before the ignition device 13 is activated. When the ignition device 13 is activated at time t2 to ignite the combustible gas M, if backfire (self-ignition) occurs, the pulse turns ON at time t1, which is the time Ta before time t2, and turns OFF at time t4. The control device 15 determines that backfire has occurred when the pulse turns ON at time t1, which is before time t2 when the ignition device 13 is activated.

[0068] Third embodiment The method of determining the combustion state of fuel by the shock wave generating device 10A is almost the same as that in the first embodiment, and therefore a description thereof will be omitted.

[0069] In the third embodiment, the position of the flame occurrence timing detection sensors 14, 14B is changed from that of the first embodiment. However, the flame occurrence timing detection sensors 14, 14B of the third embodiment may be added to the flame occurrence timing detection sensor 14 of the first embodiment. In this case, the detonation can be determined with higher accuracy.

[0070] [Effects of this embodiment] The shock wave generating device of the first embodiment includes a combustion device 11 having a gas passage 21 through which combustion gas flows from a base end to a tip end and an opening at the tip end, a combustible gas supply device 12 that supplies combustible gas M from the base end of the combustion device 11 to the inside, an ignition device 13 that ignites the combustible gas M supplied to the combustion device 11, flame generation timing detection sensors 14, 14A, 14B that detect the timing of generation of a flame C by combustion of the combustible gas M, and a control device (determination device) 15 that determines the self-ignition of the combustible gas M before ignition by the ignition device 13 based on the detection results of the flame generation timing detection sensors 14, 14A, 14B.

[0071] According to the shock wave generating device of the first aspect, the control device 15 determines the self-ignition of the combustible gas M before ignition by the ignition device 13 based on the timing of generation of the flame C by the combustion of the combustible gas M. As a result, the combustion state of the fuel can be determined.

[0072] The shock wave generating device according to the second embodiment is the shock wave generating device according to the first embodiment, and further, the control device 15 judges detonation and deflagration based on the propagation speed of the flame C detected by the flame occurrence timing detection sensor 14. This makes it possible to judge the combustion state of the fuel in detail.

[0073] The shock wave generating device according to the third embodiment is the shock wave generating device according to the second embodiment, and further, when the control device 15 judges that a detonation has occurred, estimates the intensity of the detonation wave based on the propagation speed of the flame C. In this way, by estimating the intensity of the detonation wave, the intensity of the detonation wave can be adjusted according to the application destination of the shock wave.

[0074] The shock wave generating device according to the fourth aspect is the shock wave generating device according to any one of the first to third aspects, and further, the flame occurrence timing detection sensors 14, 14A, and 14B are optical sensors that detect light emitted from the flame. This makes it possible to easily identify the flame by detecting infrared light, visible light, and ultraviolet light.

[0075] The shock wave generating device according to the fifth aspect is the shock wave generating device according to any one of the first to fourth aspects, and further includes a combustion device 11 having a detonator 22 with a base end 22a connected to a combustible gas supply device 12 and a combustor 23 with a base end 23a connected to a tip 22b of the detonator 22, and a flame occurrence timing detection sensor 14 is disposed facing an opening 23c of the combustor 23. This allows the single flame occurrence timing detection sensor 14 to easily detect a flame occurring in the combustor 23.

[0076] The shock wave generating device according to the sixth aspect is the shock wave generating device according to any one of the first to fifth aspects, and further includes a combustion device 11 having a detonator 22 with a base end 22a connected to a combustible gas supply device 12 and a combustor 23 with a base end 23a connected to a tip 22b of the detonator 22, and a plurality of flame occurrence timing detection sensors 14A, 14B are arranged at intervals in the gas flow direction in the combustor 23. This allows the flame occurring in the combustor 23 to be appropriately detected.

[0077] The shock wave generating device according to the seventh aspect is the shock wave generating device according to any one of the first to sixth aspects, and further, when the control device 15 determines the spontaneous ignition of the flammable gas M, the flammable gas supply device 12 stops the supply of the flammable gas M. This can improve safety.

[0078] The shock wave generating device according to the eighth aspect is the shock wave generating device according to the seventh aspect, and further, when the control device 15 determines the self-ignition of the combustible gas M, the purge gas P is supplied to the inside of the combustion device 11. This can improve safety.

[0079] In the above-mentioned embodiment, the shock wave generating device is applied to a dust removing device that removes dust attached to the inner wall surface or the outer surface of a heat transfer tube of a furnace such as a waste incinerator, a coal gasification combined cycle power generation facility, or a power boiler for power generation, but the application is not limited to these. The shock wave generating device can be applied to, for example, a propulsion engine that radiates a shock wave from an opening of a combustion device and receives the reaction force to generate thrust, a power engine that rotates a turbine, a device that radiates a shock wave from an opening of a combustor and exerts a physical action on an object placed near the opening by using the high pressure of the shock wave (destruction of a structure, separation of materials, etc.), and a device that exerts a physical action on an object placed inside the combustion device by using the high pressure of the shock wave (destruction of a structure, separation of materials, etc.). [Explanation of symbols]

[0080] 10,10A shock wave generator 11 Combustion equipment 12. Flammable gas supply equipment 13 Ignition system 14 Flame occurrence detection sensor 14A First flame occurrence detection sensor 14B Second flame occurrence detection sensor 15 Control device (judgment device) 21 Gas passage 22 Detonator 23 Combustor 24 1st aisle 25 2nd aisle 31 Fuel supply section 32 Fuel supply route 33 Fuel Cylinder 34 Pressure reducing valve 35 Mass Flow Controller 36 Safety device 37 Fuel supply valve 38 Check valve 41 Oxidant supply section 42 Oxidant supply route 43 Oxidizer Cylinder 44 Pressure reducing valve 45 Mass Flow Controller 46 Safety device 47 Oxidizer supply valve 48 Check valve 51 Cross Joint 52 Combustible gas supply route 53 Purge gas path 54 Blower 55 Purge gas supply valve 61 Wall 62 Optical window 63 Optical Fiber 64 Mounting material F fuel A Oxidizing agent M Flammable gas C Flame S shock wave

Claims

1. a combustion device provided with a gas passage through which a combustion gas flows from a base end to a tip end and with an opening provided at the tip end; a combustible gas supply device that supplies combustible gas from the base end of the combustion device to an inside of the combustion device; an ignition device that ignites the flammable gas supplied to the combustion device; a flame occurrence timing detection sensor for detecting a timing of a flame occurrence due to combustion of the combustible gas; a determination device that determines self-ignition of the flammable gas before ignition by the ignition device based on a detection result of the flame generation timing detection sensor; Equipped with The determination device is a device for determining whether a detonation or deflagration is occurring based on the propagation speed of the flame detected by the flame occurrence timing detection sensor, A threshold value is set between deflagration and detonation, which is a pulse length according to the propagation speed of the flame, and the determination device estimates the intensity of the detonation wave based on the pulse length detected by the flame occurrence time detection sensor when the pulse length, which is the time from the flame occurrence to the flame extinction detected by the flame occurrence time detection sensor, is equal to or less than the threshold value and determines that the detonation is occurring. Shock wave generator.

2. The flame occurrence timing detection sensor is an optical sensor that detects light emission from the flame. The shock wave generating device according to claim 1 .

3. The combustion device includes a detonator having a base end connected to a combustible gas supply device, and a combustor having a base end connected to a tip end of the detonator, and the flame generation timing detection sensor is disposed facing the opening of the combustor. The shock wave generating device according to claim 1 .

4. The combustion device includes a detonator having a base end connected to a combustible gas supply device, and a combustor having a base end connected to a tip end of the detonator, and the flame generation timing detection sensor is disposed in the combustor at intervals in a gas flow direction. The shock wave generating device according to claim 1 .

5. When the determination device determines that the flammable gas has spontaneously ignited, the flammable gas supply device stops supplying the flammable gas. The shock wave generating device according to claim 1 .

6. When the determination device determines that the combustible gas has spontaneously ignited, a purge gas is supplied to the inside of the combustion device. The shock wave generating device according to claim 5.

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