Self-ignition preventing device

Abstract

In a self-ignition preventing device, increase in cost of a member, maintenance cost is suppressed, and self-ignition of a combustible gas is appropriately suppressed. The self-ignition preventing device is provided with: a pipe which is capable of filling a combustible gas and is capable of communicating with an object region; an enlarged pipe which is provided between the pipe and the object region and has an inner diameter larger than an inner diameter of the pipe; and an ejection portion which ejects a non-combustible gas from an outer peripheral portion of the enlarged pipe toward a central portion side.

Description

Technical Field

[0001] This disclosure relates to a spontaneous combustion prevention device for preventing spontaneous combustion of flammable gases in piping. Background Technology

[0002] For example, in waste incinerators, gasification combined cycle (IGCC) power plants, and power generation boilers, dust contained in the exhaust gas adheres to the inner wall of the furnace and the outer surface of the heat transfer tubes. The dust adhering to the inner wall of the furnace and the outer surface of the heat transfer tubes reduces the heat transfer rate, thus worsening the heat recovery efficiency, or it becomes a resistance to the flow of exhaust gas, thus reducing the performance of the furnace.

[0003] As a device for removing dust adhering to the inner wall of the furnace and the outer surface of the heat transfer tubes, there is, for example, the device described in Patent Document 1. The dust removal device described in Patent Document 1 fills a piping system communicating with the interior of the furnace with a combustible gas, and generates a shock wave from a detonation by igniting the combustible gas. According to this dust removal device, the adhering dust can be dispersed and removed by the shock wave acting on the inner wall surface of the furnace and the outer surface of the heat transfer tubes.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent Application Publication No. 2005 / 0126594 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In existing dust removal devices, multiple isolation valves are installed on the piping. When not in operation, these valves are moved to the closed position to prevent spontaneous combustion of flammable gases filling the piping. However, with large-diameter piping, this leads to larger valves, increasing component and maintenance costs. Furthermore, because the isolation valves are located in high-temperature environments, they may malfunction, making it difficult to effectively prevent spontaneous combustion of flammable gases.

[0009] This disclosure is a technology for solving the above-mentioned problems, and its purpose is to provide a spontaneous combustion prevention device that suppresses the increase in component costs and maintenance costs and appropriately suppresses the spontaneous combustion of flammable gases.

[0010] Solution for solving the problem

[0011] The spontaneous combustion prevention device of this disclosure for achieving the above-mentioned objectives includes: a piping capable of being filled with a flammable gas and capable of communicating with a target area; an enlargement pipe disposed between the piping and the target area and having an inner diameter larger than that of the piping; and an ejection portion that ejects a non-flammable gas from the outer periphery of the enlargement pipe toward the center.

[0012] Invention Effects

[0013] The spontaneous combustion prevention device according to this disclosure can suppress the increase in component costs and maintenance costs, and can appropriately suppress the spontaneous combustion of flammable gases. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of the furnace chamber of the self-ignition prevention device according to the first embodiment.

[0015] Figure 2 This is a front view showing the self-ignition prevention device as seen from the furnace side.

[0016] Figure 3 This is a cross-sectional view of the furnace chamber of the self-ignition prevention device according to the second embodiment.

[0017] Figure 4 This is a cross-sectional view of the furnace chamber of the self-ignition prevention device according to the third embodiment.

[0018] Figure 5 This is a front view showing the self-ignition prevention device as seen from the furnace side.

[0019] Figure 6 This is a cross-sectional view of the furnace chamber of the self-ignition prevention device according to the fourth embodiment.

[0020] Figure 7 This is a cross-sectional view of the furnace chamber of the self-ignition prevention device according to the fifth embodiment.

[0021] Explanation of reference numerals in the attached figures:

[0022] 10, 10A, 10B, 10C, 10D... Spontaneous combustion prevention devices;

[0023] 11...Piping;

[0024] 12...Expanding tube;

[0025] 13, 13A, 13B... ejection section;

[0026] 21...Outer bobbin;

[0027] 22, 22a, 22b... Gas flow sections;

[0028] 23... header;

[0029] 24, 24a, 24b... gas space section;

[0030] Ports 25, 25a, 25b...

[0031] 26, 26a, 26b... gas supply pipelines;

[0032] 27...Gas supply source;

[0033] 28, 28a, 28b... Opening and closing valves;

[0034] 31...Ejection hole, first ejection hole;

[0035] 32...Second ejection port;

[0036] 31a...Upstream side ejection port;

[0037] 31b...downstream ejection port;

[0038] 41... Flow sensor;

[0039] 42...Control Department;

[0040] 43...Temperature sensor;

[0041] 101...furnace;

[0042] 102...furnace wall;

[0043] 103...Internal space (object region);

[0044] G1...exhaust gas;

[0045] G2...flammable gas;

[0046] G3, G3a, G3b, G4... non-flammable gases;

[0047] F...secondary flow. Detailed Implementation

[0048] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to these embodiments. Furthermore, in cases where multiple embodiments exist, embodiments formed by combining various embodiments are also included. Additionally, the constituent elements of the embodiments include elements readily conceived by those skilled in the art, substantially identical elements, and elements of so-called equal scope.

[0049] [First Implementation Method]

[0050] <Structure of the Spontaneous Combustion Prevention Device>

[0051] Figure 1 This is a cross-sectional view of the furnace chamber showing the self-ignition prevention device of the first embodiment. Figure 2 This is a front view showing the self-ignition prevention device as seen from the furnace side.

[0052] The spontaneous combustion prevention device of the first embodiment is a dust removal device used to remove dust adhering to the inner wall surface and outer surface of heat transfer tubes of furnaces such as waste incinerators, coal gasification combined power generation equipment, and power generation boilers (hereinafter referred to as boilers). The dust removal device supplies combustible gas into the furnace through a pipe communicating with the interior of the furnace, igniting the combustible gas and generating a shock wave from a detonation. The dust removal device disperses and removes the adhering dust by acting on the inner wall of the furnace and the outer surface of the heat transfer tubes through the shock wave generated by the detonation.

[0053] The spontaneous combustion prevention device is installed in the dust removal device to prevent the spontaneous combustion of combustible gases that fill the piping due to heat caused by the rising exhaust gas inside the furnace during boiler operation.

[0054] like Figure 1 and Figure 2 As shown, the spontaneous combustion prevention device 10 includes a piping 11, an expansion pipe 12, and an ejection section 13.

[0055] The furnace 101 has a furnace wall 102. The furnace 101 has an internal space 103 defined by the inner wall surface 102a of the furnace wall 102. Heat transfer tubes constituting a heat exchanger (not shown) are arranged in the internal space 103 of the furnace 101. High-temperature exhaust gas G1 flows in a predetermined direction within the internal space 103 of the furnace 101. The flow direction of the high-temperature exhaust gas G1 varies depending on the position of the internal space 103, its surrounding shape, etc. The following description explains the upward movement of the high-temperature exhaust gas G1 within the internal space 103.

[0056] Pipe 11 is capable of supplying combustible gas G2 to the interior space 103, which is the target area. Pipe 11 is, for example, cylindrical in shape, with the same inner diameter along its length. However, pipe 11 is not limited to a cylindrical shape and may also be a polygonal cylindrical shape. One end of pipe 11 is connected to a supply device for combustible gas G2 (not shown), and the other end is connected to an expansion pipe 12.

[0057] An expansion pipe 12 is disposed between the piping 11 and the furnace wall 102 (internal space 103) of the furnace 101. The inner diameter of the expansion pipe 12 on the furnace wall 102 side is larger than the inner diameter of the piping 11. The expansion pipe 12 continuously and uniformly expands in diameter from the piping 11 side toward the furnace wall 102 (internal space 103) side. That is, one axial end of the expansion pipe 12 has the same diameter as the piping 11 and is connected to the other end of the piping 11. The diameter of the expansion pipe 12 gradually increases from one axial end toward the other end and is connected to the furnace wall 102. It should be noted that, due to the reaction force generated by the shock wave from the detonation of the combustible gas G2 inside the expansion pipe 12, the expansion pipe 12 can also move freely relative to the connection part of the furnace wall 102.

[0058] The ejector 13 ejects non-flammable gas G3 from the outer periphery of the expansion tube 12 toward the center. The ejector 13 is located at the other end of the expansion tube 12, i.e., the furnace 101 (internal space 103) side.

[0059] An outer cylinder 21 is disposed on the outer side of the other end of the expanding tube 12. The outer cylinder 21 is cylindrical with a diameter larger than that of the expanding tube 12, and like the expanding tube 12, it expands continuously and uniformly from one end to the other in the axial direction. The inner circumferential surface of the outer cylinder 21 is disposed with a gap between it and the outer circumferential surface of the expanding tube 12, and the outer circumferential surface is fitted and fixed to the through hole 102b of the furnace wall 102. Therefore, the other end of the expanding tube 12 is disposed inside the furnace wall 102, and the entire outer cylinder 21 is disposed inside the furnace wall 102. It should be noted that the outer cylinder 21 can also be connected to the furnace wall 102 in a way that allows it to move freely, just like the expanding tube 12.

[0060] The outer tube 21 has an outer tube portion 21a and a flange portion 21b. The outer tube portion 21a is disposed with a gap between it and the outer peripheral surface of the expanding tube 12. The flange portion 21b is disposed on the other end side of the outer tube 21 in the axial direction, with its outer peripheral portion connected to the other end of the outer tube portion 21a and its inner peripheral portion connected to the other end of the expanding tube 12. Therefore, a cylindrical gas flow section 22 is formed between the expanding tube 12 and the outer tube 21.

[0061] Additionally, a manifold 23 is disposed at one axial end of the outer cylinder 21. The manifold 23 is annular and has an L-shaped cross-section. One end of the manifold 23 in the width direction is fixed to the outer wall surface 102c of the furnace wall 102, and the other end is fixed to the outer peripheral surface of the expansion pipe 12. Therefore, the manifold 23 divides an annular gas space 24 between the furnace wall 102 and the expansion pipe 12. The gas space 24 is connected to one end of the gas flow section 22. It should be noted that the manifold 23 can also be connected to the furnace wall 102 in a manner similar to the expansion pipe 12 and the outer cylinder 21, allowing for free movement. Alternatively, the manifold 23 can be fixed to the outer cylinder 21 to divide the gas space 24.

[0062] The ejector section 13 has a plurality of ejection holes 31 (eight in this embodiment) for ejecting non-flammable gas G3. The plurality of ejection holes 31 are formed at the other end side of the expansion tube 12 along its axial direction, i.e., the side of the internal space 103 of the furnace 101. The plurality of ejection holes 31 are openings forming slits along the circumference of the expansion tube 12. However, the number of ejection holes 31 is not limited. Furthermore, the ejection holes 31 are not limited to a slit shape and can also be circular holes.

[0063] The plurality of ejection holes 31 constituting the ejection section 13 eject non-combustible gas G3 in an inclined direction relative to the radial direction of the expansion tube 12 toward the internal space 103 of the furnace 101. That is, one end of the expansion tube 12 expands in diameter toward the other end. The plurality of ejection holes 31 are holes that penetrate in a direction orthogonal to the other end of the expanded tube 12. Therefore, the plurality of ejection holes 31 eject non-combustible gas G3 from the outer periphery of the expansion tube 12 toward the internal space 103.

[0064] However, the expanding tube 12 is set to a predetermined expansion ratio. For example, when the inner diameter of the expanding tube 12 at one end is R1 and the inner diameter at the other end is R2, it is preferably set to an area ratio of (R2 / 2). 2 π / (R1 / 2) 2 π = 1.4 to 4.0. Furthermore, the angle α between the inner surface of the expansion tube 12 and the centerline is preferably set to be 10 to 50 degrees. Additionally, the ejection port 31 is preferably set to an ejection angle β of 0 to 45 degrees relative to the radial direction of the non-flammable gas G3 relative to the expansion tube 12.

[0065] The manifold 23 is connected to one end of the gas supply line 26 via port 25. The gas supply line 26 is connected to a gas supply source 27 at the other end, and an on / off valve 28 is provided midway through the line. Here, the gas supply source 27 is, for example, a blower or compressor, supplying air or compressed air as the non-flammable gas G3. However, the gas supply source 27 is not limited to this structure. For example, the non-flammable gas G3 may not be air, but a gas with a lower oxygen ratio than air, or an inert gas (nitrogen, argon, etc.), and the gas supply source 27 may be a tank for storing these gases.

[0066] Therefore, when the on / off valve 28 is opened, non-flammable gas G3 is supplied from the gas supply source 27 to the gas supply line 26 and then to the gas space 24 via the port 25. The non-flammable gas G3 supplied to the gas space 24 flows in the gas flow section 22 toward the other end of the expansion tube 12 and is ejected from the plurality of ejection holes 31 toward the center of the expansion tube 12.

[0067] <Function of Spontaneous Combustion Prevention Devices>

[0068] In the furnace 101, when dust accumulates on the inner wall surface 102a of the furnace wall 102 and the heat transfer tubes of the heat exchanger (not shown) due to long-term use, the dust removal device is activated. Specifically, combustible gas G2 is supplied to and filled into the piping 11 via a supply device, and then ignited. The combustible gas G2 then burns inside the piping 11, generating a shock wave from the detonation. This shock wave propagates through the piping 11 and the expansion pipe 12 into the internal space 103, acting on the inner wall surface 102a of the furnace wall 102 and the outer surface of the heat transfer tubes, blowing away and removing the attached dust. Meanwhile, the shock wave generated by the detonation in the piping 11 propagates through the expanded diameter expansion pipe 12 into the internal space 103 of the furnace 101. Therefore, by expanding the supersonic airflow ejected along with the detonation airflow at an appropriate area ratio, the detonation airflow and jet stream can be efficiently guided into the internal space 103. When using the dust removal device to remove dust adhering to the inner wall surface 102a of the furnace wall 102 and the outer surface of the heat transfer tube, stop the operation of the dust removal device.

[0069] When dust is removed using the dust removal device described above, the flammable gas G2 filled inside the piping 11 and the expansion pipe 12 may spontaneously combust. Therefore, when the dust removal device is operating, the spontaneous combustion prevention device 10 is activated. That is, the on / off valve 28 is opened, and the non-flammable gas G3 is supplied from the gas supply source 27 to the gas space 24 through the gas supply line 26. As a result, the non-flammable gas G3 filled in the gas space 24 flows through the gas flow section 22 toward the other end of the expansion pipe 12 and is ejected from the plurality of ejection holes 31 toward the center of the expansion pipe 12.

[0070] At this time, the ejector section 13 ejects non-flammable gas G3 from multiple ejector holes 31 toward the center of the expansion tube 12, forming an air curtain between the interior of the expansion tube 12 and the interior space 103 of the furnace 101. This air curtain of non-flammable gas G3 separates the interior of the expansion tube 12 from the interior space 103, thus preventing, for example, rising exhaust gas G1 from entering the interior of the expansion tube 12 within the interior space 103. Therefore, spontaneous combustion of the combustible gas G2 filling the piping 11 due to contact with the high-temperature exhaust gas G1 can be suppressed.

[0071] However, due to the flow velocity and deviation of the exhaust gas G1 rising in the internal space 103, a portion of the exhaust gas G1 may pass through the air curtain of the non-combustible gas G3 and enter the expansion pipe 12. At this time, the inner diameter (area) of the expansion pipe 12 on the furnace wall 102 side is larger than that on the piping 11 side. Therefore, the exhaust gas G1 entering the expansion pipe 12 from the internal space 103 becomes... Figure 1The secondary flow F rotates counterclockwise in the middle. Therefore, the exhaust gas G1 that enters into the expansion pipe 12 becomes a secondary flow F and rotates and stagnates in the expansion pipe 12, making it difficult to flow to the side of the piping 11, which can suppress the spontaneous combustion of the combustible gas G2 filled in the piping 11.

[0072] Furthermore, even if a portion of the exhaust gas G1 that enters the expansion pipe 12 comes into contact with the combustible gas G2 filling the piping 11, the temperature of the exhaust gas G1 decreases during its flow through the expansion pipe 12. That is, the combustible gas G2 in the piping 11 mixes with the cooled exhaust gas G1 and is diluted, thus preventing spontaneous combustion and reducing its concentration. Therefore, even if the mixture of combustible gas G2 and exhaust gas G1 returns to the internal space 103 through the expansion pipe 12, the spontaneous combustion of combustible gas G2 can be suppressed.

[0073] It should be noted that, in the above description, the spontaneous combustion prevention device 10 is configured to operate when the dust removal device removes dust adhering to the inner wall surface 102a of the furnace wall 102 and the outer surface of the heat transfer tube, but it is not limited to this structure. The spontaneous combustion prevention device 10 can operate at all times.

[0074] [Second Implementation]

[0075] Figure 3 This is a cross-sectional view of the furnace chamber showing the self-ignition prevention device according to the second embodiment. It should be noted that components having the same functions as those in the first embodiment described above are labeled with the same reference numerals, and detailed descriptions are omitted.

[0076] In the second embodiment, such as Figure 3 As shown, the spontaneous combustion prevention device 10A includes a piping 11, an expansion pipe 12, and an ejection section 13A.

[0077] An expansion pipe 12 is disposed between the piping 11 and the internal space 103 of the furnace 101. One end of the expansion pipe 12 has the same diameter as the piping 11 and is connected to the other end of the piping 11. The diameter gradually increases towards the other end and is connected to the furnace wall 102. An ejection section 13A ejects non-flammable gases G3 and G4 from the outer periphery of the expansion pipe 12 towards the center. The ejection section 13 has multiple first ejection holes 31 and multiple second ejection holes 32. The first ejection holes 31 are disposed on the furnace 101 (internal space 103) side of the expansion pipe 12 and eject non-flammable gas G3. The second ejection holes 32 are disposed on the piping 11 side of the expansion pipe 12 and eject non-flammable gas G4. The multiple first ejection holes 31 and second ejection holes 32 constituting the ejection section 13 eject non-flammable gas G3 in an inclined direction relative to the radial direction of the expansion pipe 12 towards the internal space 103 of the furnace 101.

[0078] An outer tube 21 is disposed on the outer side of the other end of the expanding tube 12, forming a cylindrical gas flow section 22 between the expanding tube 12 and the outer tube 21. Additionally, a manifold 23 is disposed on one axial end of the outer tube 21. The manifold 23 divides into a gas space section 24 that communicates with the gas flow section 22 and the second ejector hole 32. The manifold 23 is connected to one end of a gas supply line 26 via a port 25. A gas supply source 27 is connected to the other end of the gas supply line 26, and an on / off valve 28 is provided in the middle of the line.

[0079] Therefore, when the spontaneous combustion prevention device 10 is activated, non-flammable gas G3 is supplied from the gas supply line 26 to the gas space 24 and ejected from the plurality of second ejection holes 32 toward the center of the expansion tube 12. In addition, non-flammable gas G3 flows from the gas space 24 through the gas flow section 22 toward the other end of the expansion tube 12 and is ejected from the plurality of first ejection holes 31 toward the center of the expansion tube 12.

[0080] At this time, the first ejector hole 31 ejects non-flammable gas G3 from the other end of the expander pipe 12 toward the center, forming an air curtain between the interior of the expander pipe 12 and the interior space 103 of the furnace 101. Additionally, the second ejector hole 32 ejects non-flammable gas G4 from one end of the expander pipe 12 toward the center, forming an air curtain between the interior of the expander pipe 12 and the interior of the piping 11. The two air curtains of non-flammable gas G3 separate the interior of the piping 11 from the interior of the expander pipe 12 and the interior space 103. The air curtain of non-flammable gas G3 separates the interior of the expander pipe 12 from the interior space 103. Furthermore, the air curtain of non-flammable gas G4 separates the interior of the piping 11 from the interior of the expander pipe 12. Thus, the intrusion of exhaust gas G1 rising from the interior space 103 into the interior of the expander pipe 12 is suppressed by the air curtain of non-flammable gas G3. Furthermore, the air curtain of non-flammable gas G4 also suppresses the intrusion of combustible gas G2 from the interior of the piping 11 into the interior of the expander pipe 12. Therefore, it is possible to suppress the spontaneous combustion of combustible gas G2 filled in piping 11 caused by exhaust gas G1.

[0081] It should be noted that, in the above description, the ejection section 13 is provided with a first ejection hole 31 and a second ejection hole 32, but it is not limited to this structure. For example, the ejection section 13 may be composed of only the second ejection hole 32.

[0082] [Third Implementation Method]

[0083] Figure 4 This is a cross-sectional view of the furnace chamber showing the self-ignition prevention device according to the third embodiment. Figure 5 This is a front view showing the spontaneous combustion prevention device as seen from the furnace side. It should be noted that components having the same functions as in the first embodiment described above are labeled with the same reference numerals, and detailed descriptions are omitted.

[0084] In the third embodiment, such as Figure 4 and Figure 5 As shown, the spontaneous combustion prevention device 10B includes a piping 11, an expansion pipe 12, and an ejection section 13B.

[0085] An expansion pipe 12 is disposed between the piping 11 and the internal space 103 of the furnace 101. One end of the expansion pipe 12 has the same diameter as the piping 11 and is connected to the other end of the piping 11. The diameter gradually increases towards the other end and is connected to the furnace wall 102. An ejector section 13B ejects non-flammable gases G3a and G3b from the outer periphery of the expansion pipe 12 towards the center. The ejector section 13B has multiple upstream ejector holes (upstream ejector sections) 31a and multiple downstream ejector holes (downstream ejector sections) 31b. The upstream ejector holes 31a and downstream ejector holes 31b are disposed on the furnace 101 side of the expansion pipe 12, respectively ejecting non-flammable gases G3a and G3b.

[0086] The upstream side ejector hole 31a is positioned upstream of the flow direction of the exhaust gas G1 rising in the internal space 103 of the furnace 101. Figure 4 The downstream side ejector hole 31b is located on the downstream side of the flow direction of the exhaust gas G1 rising in the internal space 103 of the furnace 101. Figure 4 (Above side). In this embodiment, four upstream ejector holes 31a are arranged below the expansion pipe 12, and four downstream ejector holes 31b are arranged above the expansion pipe 12, but their number is not limited and may not be the same. Moreover, the amount of non-flammable gas G3b ejected from the downstream ejector holes 31b is greater than the amount of non-flammable gas G3a ejected from the upstream ejector holes 31a. Specifically, it is preferable that the deviation of the flow rates of non-flammable gases G3a and G3b, i.e., the deviation of the dynamic pressure of the air curtain, is set to be at least 0.5 times the dynamic pressure of, for example, the rising exhaust gas G1 in the internal space 103.

[0087] An outer tube 21 is disposed on the outer side of the other end of the expanding tube 12, forming cylindrical gas flow sections 22a and 22b between the expanding tube 12 and the outer tube 21. A partition plate 21c is provided on the inner surface of both horizontally sides of the outer tube 21, dividing the lower gas flow section 22a and the upper gas flow section 22b. Furthermore, a manifold 23 is provided at one axial end of the outer tube 21. The manifold 23 divides into gas spaces 24a and 24b that communicate with the gas flow sections 22a and 22b. A partition plate (not shown) is provided on the inner surface of both horizontally sides of the manifold 23, dividing the lower gas space 24a and the upper gas space 24b. Gas flow section 22a communicates with gas space 24a, and gas flow section 22b communicates with gas space 24b. Manifold 23 is connected to one end of gas supply line 26a via port 25a, which communicates with gas space section 24a, and to gas supply source 27 at the other end. Manifold 23 is connected to one end of gas supply line 26b via port 25b, which communicates with gas space section 24b, and to gas supply source 27 at the other end. Gas supply lines 26a and 26b are equipped with on / off valves 28a and 28b at intermediate points. On / off valves 28a and 28b are flow regulating valves.

[0088] Therefore, when the spontaneous combustion prevention device 10 is activated, non-flammable gases G3a and G3b are supplied from gas supply lines 26a and 26b to gas spaces 24a and 24b, and flow through gas flow sections 22a and 22b toward the other end of the expansion pipe 12. Furthermore, non-flammable gas G3a is ejected from multiple upstream ejection holes 31a toward the center of the expansion pipe 12, and non-flammable gas G3b is ejected from multiple downstream ejection holes 31b toward the center of the expansion pipe 12.

[0089] That is, the upstream ejector hole 31a ejects non-flammable gas G3a along the rising exhaust gas G1 in the internal space 103, and the downstream ejector hole 31b ejects non-flammable gas G3a opposite to the rising exhaust gas G1 in the internal space 103. At this time, the opening degree of the opening and closing valves 28a and 28b is adjusted so that the amount of non-flammable gas G3b ejected from the downstream ejector hole 31b is greater than the amount of non-flammable gas G3a ejected from the upstream ejector hole 31a.

[0090] The exhaust gas G1 rising in the internal space 103 may, due to flow velocity, flow deviation, etc., partially pass through the air curtain of the non-flammable gas G3 and enter the expansion pipe 12. Furthermore, the exhaust gas G1 entering the expansion pipe 12 from the internal space 103 becomes... Figure 4The secondary flow F rotates counterclockwise. Here, the downstream ejector hole 31b ejects a large amount of non-flammable gas G3b in a manner opposite to the flow of exhaust gas G1 that enters the expansion pipe 12 from the internal space 103. Therefore, the large amount of non-flammable gas G3b hinders the flow of exhaust gas G1 that enters the expansion pipe 12 from the internal space 103, suppresses the intrusion of exhaust gas G1 into the expansion pipe 12, and suppresses the spontaneous combustion of flammable gas G2 filled in the piping 11.

[0091] It should be noted that, in the above description, the ejector section 13B is provided with multiple upstream ejector holes 31a and multiple downstream ejector holes 31b, so that the ejection amounts of non-flammable gas G3a from the upstream ejector holes 31a and non-flammable gas G3b from the downstream ejector holes 31b are different, but this structure is not limited to this. For example, the types of ejector holes that cause different ejection amounts are not limited to two, but may be three or more.

[0092] [Fourth Implementation Method]

[0093] Figure 6 This is a cross-sectional view of the furnace chamber showing the self-ignition prevention device according to the fourth embodiment. It should be noted that components having the same functions as those in the first embodiment described above are labeled with the same reference numerals, and detailed descriptions are omitted.

[0094] In the fourth embodiment, such as Figure 6 As shown, the spontaneous combustion prevention device 10C includes a piping 11, an expansion pipe 12, and an ejection section 13. Furthermore, the spontaneous combustion prevention device 10C can adjust the flow rate of the non-flammable gas G3 ejected by the ejection section 13 according to the properties of the flammable gas G2, etc. Here, the properties of the flammable gas G2 refer to, for example, the flow rate of the flammable gas G2 flowing in the piping 11.

[0095] Pipeline 11 is internally equipped with a flow sensor 41 that measures the flow rate of combustible gas G2. Control unit 42 adjusts the opening degree of on / off valve 28 based on the flow rate of combustible gas G2 detected by flow sensor 41. The greater the flow rate of combustible gas G2 in pipeline 11, the greater the opening degree of on / off valve 28 adjusted by control unit 42. That is, the greater the flow rate of combustible gas G2 in pipeline 11, the greater the flow rate of non-combustible gas G3 injected from multiple injection holes 31 by ejection unit 13.

[0096] It should be noted that, in the above description, the detection unit for detecting the properties of combustible gas G2 is not limited to flow sensor 41. As a detection unit for detecting properties such as flow rate and concentration of combustible gas G2, a speed sensor for detecting the flow rate of combustible gas G2, a concentration sensor for detecting the concentration of combustible gas G2, a supply quantity setting value in the combustible gas G2 supply device, a valve opening sensor, a combustible gas G2 sampling and measuring device, a laser measuring device, etc., can also be used. Furthermore, a map can be prepared in advance, showing the injection quantity of non-combustible gas G3 relative to the supply quantity setting value in the combustible gas G2 supply device, and the opening of the on / off valve 28 can be adjusted based on this map.

[0097] [Fifth Implementation]

[0098] Figure 7 This is a cross-sectional view of the furnace chamber showing the self-ignition prevention device according to the fifth embodiment. It should be noted that components having the same functions as those in the first embodiment described above are labeled with the same reference numerals, and detailed descriptions are omitted.

[0099] In the fifth embodiment, such as Figure 7 As shown, the spontaneous combustion prevention device 10D includes a piping 11, an expansion pipe 12, and an ejection section 13. Furthermore, the spontaneous combustion prevention device 10C can adjust the flow rate of the non-flammable gas G3 ejected from the ejection section 13 according to the characteristics of the exhaust gas G1. Here, the characteristics of the exhaust gas G1 refer to, for example, the temperature of the exhaust gas G1 immersed in the piping 11.

[0100] The expansion pipe 12 is internally equipped with a temperature sensor 43 that measures the temperature of the exhaust gas G1. The control unit 42 adjusts the opening degree of the on / off valve 28 based on the temperature of the exhaust gas G1 detected by the temperature sensor 43. The higher the temperature of the exhaust gas G1 entering the expansion pipe 12, the larger the opening degree of the on / off valve 28 is adjusted by the control unit 42. That is, the higher the temperature of the exhaust gas G1 entering the expansion pipe 12, the greater the flow rate of the non-flammable gas G3 injected from the multiple injection holes 31 by the ejection unit 13.

[0101] It should be noted that, in the above description, the detection unit for detecting the properties of exhaust gas G1 is not limited to temperature sensor 43. Other detection units for the properties of exhaust gas G1 may include temperature sensors that detect the temperature of the inner circumferential surface of the expansion pipe 12, temperature sensors that detect the temperature of exhaust gas G1 rising in the internal space 103, temperature sensors that detect the temperature of the inner wall surface 102a of the furnace wall 102, and flow sensors (velocity sensors) that detect the flow rate (velocity) of exhaust gas G1 entering the expansion pipe 12. Furthermore, a pre-set image of the injection volume of non-flammable gas G3 relative to the temperature of exhaust gas G1 entering the expansion pipe 12 is prepared, and the opening degree of the on / off valve 28 is adjusted based on this image. Alternatively, PID control can be performed based on the detected properties of exhaust gas G1 to adjust the opening degree of the on / off valve 28.

[0102] [Effects of this implementation method]

[0103] The self-ignition prevention device of the first embodiment includes: a pipe 11 that can be filled with flammable gas G2 and can communicate with the internal space (target area) 103 of the furnace 101; an expansion pipe 12 disposed between the pipe 11 and the furnace wall 102 (internal space 103) and having an inner diameter larger than the inner diameter of the pipe 11; and an ejection portion 13, 13A, 13B that ejects non-flammable gas G3 from the outer periphery of the expansion pipe 12 toward the center.

[0104] According to the first embodiment of the spontaneous combustion prevention device, when combustible gas G2 is filled into the piping 11, the ejector parts 13A and 13B eject non-combustible gas G3 from the outer periphery of the expansion pipe 12 toward the center, thereby forming an air curtain between the expansion pipe 12 and the internal space 103 of the furnace 101. The air curtain of non-combustible gas G3 separates the interior of the expansion pipe 12 from the internal space 103, thus suppressing the intrusion of exhaust gas G1 into the interior of the expansion pipe 12 and suppressing the spontaneous combustion of combustible gas G2 filled in the piping 11 caused by exhaust gas G1.

[0105] Additionally, a portion of the exhaust gas G1 may pass through the air curtain of the non-flammable gas G3 and infiltrate the interior of the expansion pipe 12. This exhaust gas G1 forms a secondary flow F that circulates within the expansion pipe 12 and remains there. Therefore, the exhaust gas G1 is unlikely to flow towards the piping 11 side, thus suppressing the spontaneous combustion of the flammable gas G2 filling the piping 11.

[0106] Furthermore, even if a portion of the exhaust gas G1 that enters the expansion pipe 12 comes into contact with the combustible gas G2 filling the piping 11, the combustible gas G2 will be diluted by the mixture with the exhaust gas G1, which has a lower temperature, thus reducing the concentration of the combustible gas G2. Therefore, even if the combustible gas G2 diluted by the mixture with the exhaust gas G1 returns to the internal space 103 through the expansion pipe 12, the spontaneous combustion of the combustible gas G2 can be suppressed.

[0107] As a result, the increase in component and maintenance costs can be suppressed without the need for large valves. In addition, the non-flammable gas G3 gas curtain that separates the expansion pipe 12 and the internal space 103 only needs to be provided with an outlet 13 in the expansion pipe 12. Even if it is installed in a high-temperature environment, it will not malfunction and can appropriately suppress the spontaneous combustion of flammable gas G2.

[0108] In the second embodiment of the spontaneous combustion prevention device, the expansion pipe 12 continuously expands in diameter from the piping 11 toward the internal space 103. As a result, by expanding the diameter of the inner surface of the expansion pipe 12 without any height difference, the exhaust gas G1 that enters the expansion pipe 12 can be properly rotated and become a stagnant secondary flow F, which can suppress the spontaneous combustion of the combustible gas G2 filled in the piping 11.

[0109] In the third embodiment of the spontaneous combustion prevention device, the ejector sections 13, 13A, and 13B eject non-flammable gas G3 in an inclined direction relative to the radial direction of the expansion pipe 12 toward the internal space 103. As a result, a curtain of non-flammable gas G3 is formed in such a way that it protrudes toward the internal space 103, which can effectively suppress the intrusion of exhaust gas G1 from the internal space 103 into the expansion pipe 12 and the piping 11.

[0110] In the fourth embodiment of the spontaneous combustion prevention device, the ejection section 13 is provided on the side of the internal space 103 of the expansion pipe 12. As a result, the air curtain of non-flammable gas G3 can appropriately suppress the intrusion of exhaust gas G1 from the internal space 103 into the expansion pipe 12.

[0111] In the fifth embodiment of the spontaneous combustion prevention device, the ejection section 13A is provided on the piping 11 side of the expansion pipe 12. As a result, the air curtain of non-flammable gas G3 can appropriately suppress the intrusion of exhaust gas G1 from the expansion pipe 12 into the piping 11.

[0112] In the sixth embodiment of the spontaneous combustion prevention device, the ejection section 13B is provided with an upstream ejection hole (upstream ejection section) 31a located upstream of the flow direction of the exhaust gas G1 flowing in the internal space 103, and a downstream ejection hole (downstream ejection section) 31b located downstream of the flow direction of the exhaust gas G1 in the internal space 103. The amount of non-flammable gas G3b ejected from the downstream ejection hole 31b is greater than the amount of non-flammable gas G3a ejected from the upstream ejection hole 31a. As a result, the large amount of non-flammable gas G3b ejected from the downstream ejection hole 31b is opposed to the flow of exhaust gas G1 that is about to enter the internal space 103, which can appropriately suppress the intrusion of exhaust gas G1 from the internal space 103 into the expansion pipe 12 and the piping 11.

[0113] In the seventh embodiment of the spontaneous combustion prevention device, the flow rate of the non-flammable gas G3 ejected from the ejection sections 13, 13A, and 13B is set according to the properties of the flammable gas G2. Therefore, by setting the flow rate of the non-flammable gas G3 according to the flow rate and concentration, which are properties of the flammable gas G2, the intrusion of exhaust gas G1 from the internal space 103 into the expansion pipe 12 and the piping 11 can be appropriately suppressed by utilizing the air curtain of the non-flammable gas G3.

[0114] In the self-ignition prevention device of the eighth embodiment, the flow rate of the non-flammable gas G3 ejected from the ejection sections 13, 13A, and 13B is set according to the characteristics of the exhaust gas G1 in the internal space 103. Therefore, by setting the flow rate of the non-flammable gas G3 according to the characteristics of the exhaust gas G1, such as temperature and flow rate, the intrusion of the exhaust gas G1 from the internal space 103 into the expansion pipe 12 and the piping 11 can be appropriately suppressed by utilizing the air curtain of the non-flammable gas G3.

[0115] It should be noted that in the above embodiments, the expanding pipe 12 is designed to continuously and uniformly expand in diameter from one end connected to the piping 11 toward the other end connected to the furnace 101, but this is not a limitation. For example, the expanding pipe 12 may also be designed to expand in a discontinuous manner from one end toward the other.

[0116] In addition, in the above embodiments, the spontaneous combustion prevention devices 10, 10A, 10B, 10C, and 10D are applied to dust removal devices such as waste incinerators, coal gasification combined power generation equipment, and power generation boilers, but they can also be applied to various equipment that treat combustible gas G2.

Claims

1. A self-ignition prevention device, which is a self-ignition prevention device applied to a dust removal device for removing dust adhering to the inner wall of a furnace or the outer surface of heat transfer tubes, wherein, The spontaneous combustion prevention device includes: Piping that can be filled with flammable gas and can connect to the target area; An expansion pipe, disposed between the piping and the target area, having an inner diameter larger than the inner diameter of the piping; and The ejector section ejects non-flammable gas from the outer periphery of the expanding tube toward the center to form a gas curtain. The air curtain separates the expanding tube from the target area.

2. The spontaneous combustion prevention device according to claim 1, wherein, The enlarger pipe continuously expands in diameter from the piping toward the target area.

3. The spontaneous combustion prevention device according to claim 1 or 2, wherein, The ejector section ejects non-flammable gas in an inclined direction relative to the radial direction of the expansion tube toward the target area.

4. The spontaneous combustion prevention device according to claim 1 or 2, wherein, The ejector portion is located on the target area side of the enlarged tube.

5. The spontaneous combustion prevention device according to claim 1 or 2, wherein, The ejector portion is located on the piping side of the expansion pipe.

6. The spontaneous combustion prevention device according to claim 1 or 2, wherein, The ejector portion includes: an upstream ejector portion disposed upstream of the flow direction of the gas flowing in the target region; and a downstream ejector portion disposed downstream of the flow direction of the gas in the target region. The amount of non-flammable gas ejected from the downstream ejector is greater than the amount of non-flammable gas ejected from the upstream ejector.

7. The spontaneous combustion prevention device according to claim 1 or 2, wherein, The flow rate of the non-flammable gas ejected from the ejector is set according to the properties of the flammable gas.

8. The spontaneous combustion prevention device according to claim 1 or 2, wherein, The flow rate of the non-flammable gas ejected from the ejector is set according to the properties of the gas flowing in the target area.

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