Regenerative burner

Abstract

A regenerative burner is provided that forms a short flame length resulting from direct fire combustion, a long flame length resulting from conventional diffusion combustion, and an intermediate flame length therebetween. The present invention is provided with: supply / exhaust sections (11a, 11b) for supplying combustion-supporting gas and discharging exhaust gas through heat accumulators (12a, 12b) disposed therein; first nozzles (21a, 21b) that are disposed inside the supply / exhaust sections (11a, 11b) and that discharge fuel; second nozzles (22a, 22b) that are disposed separately from the supply / exhaust sections (11a, 11b) and that discharge fuel in the flow direction of the combustion-supporting gas supplied from the supply / exhaust sections (11a, 11b); and third nozzles (23a, 23b) that are disposed between the air supply / exhaust sections (11a, 11b) and the second nozzles (22a, 22b) and that discharge fuel to the combustion-supporting gas supplied from the air supply / exhaust sections (11a, 11b).

Description

Technical Field

[0001] The invention relates to a heat storage burner. Background Art

[0002] Conventionally, a pair of regenerative burners alternately supply combustion-supporting gas and discharge exhaust gas, recovering the exhaust gas heat to preheat the combustion-supporting gas, thereby achieving high thermal efficiency.

[0003] Patent Document 1 discloses a burner capable of varying the flame length and other characteristics by changing the ratio of the inflow and outflow of fuel gas. Patent Documents 2 and 3 disclose regenerative burners that, upon furnace startup or when the furnace temperature is below the ignition temperature, eject premixed air and fuel from a central nozzle to form a linear flame. When the furnace atmosphere reaches the fuel's ignition temperature or above, the fuel ejected directly into the furnace is diffusely combusted.

[0004] Patent document 4 discloses a regenerative burner device that arranges a pair of auxiliary fuel pipes, an air supply and exhaust section, and a main fuel pipe horizontally side by side, and adjusts the flame length and the temperature distribution in the furnace by staggering the combustion timing of the auxiliary fuel pipes and the main fuel pipes. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 60-11018 Patent Document 2: Japanese Patent Application Laid-Open No. 2003-74834 Patent Document 3: Japanese Patent Application Laid-Open No. 2008-232475 Patent Document 4: Japanese Patent No. 6448679 Summary of the Invention Technical problem to be solved by the invention

[0006] Conventionally, regenerative burners used separate methods for direct fire combustion, which has a shorter flame length, and diffusion combustion, which has a longer flame length. By adjusting the combustion rate of each, the flame length was adjusted, thereby regulating the temperature distribution within the furnace. However, in diffusion combustion, even if the combustion rate is reduced to shorten the flame length, in order to maintain stable diffusion combustion, the flame length can only be shortened to, for example, approximately 30% of the normal diffusion combustion flame length. Furthermore, in direct fire combustion, even if the combustion rate is maximized to maximize the flame length, the flame length can only be extended to a length equivalent to approximately 20% of the normal diffusion combustion flame length. To extend the flame length in direct fire combustion, the direct fire nozzle can be enlarged, but the high temperature of the flame increases nitrogen oxide (NOx) emissions. Therefore, in existing regenerative burners, there is a gap in flame length between the flame length of conventional diffusion combustion and the flame length of direct fire combustion.

[0007] Therefore, the technical problem of the present invention is to provide a regenerative burner which forms a flame length intermediate between the short flame length produced by direct-fire combustion and the long flame length produced by conventional diffusion combustion. Technical solutions used to solve technical problems

[0008] In order to solve the above-mentioned technical problems, a regenerative burner according to one embodiment of the present invention is characterized by comprising: The supply and exhaust part supplies combustion-supporting gas and discharges exhaust gas through the internally arranged heat storage body; a first nozzle disposed inside the air supply and exhaust portion and discharging fuel; a second nozzle disposed separately from the supply and exhaust portion and configured to discharge fuel along a flow direction of the combustion-supporting gas supplied from the supply and exhaust portion; and The third nozzle is disposed between the supply and exhaust portion and the second nozzle, and discharges the fuel to the combustion-supporting gas supplied from the supply and exhaust portion. Effects of the Invention

[0009] According to the present invention, by using a new type of diffusion combustion using a third nozzle, a flame length intermediate between the short flame length produced by the direct fire combustion of the first nozzle and the long flame length produced by the conventional diffusion combustion of the second nozzle can be formed. Without enlarging the first nozzle, the temperature distribution in the furnace can be adjusted while suppressing the emission of nitrogen oxides (NOx). BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a diagram schematically illustrating direct-fire combustion using an air supply and exhaust section in a regenerative burner. Figure 1 (A) indicates direct fire combustion using the first nozzle on one side, Figure 1 (B) indicates direct flame combustion using the other first nozzle. Figure 2 is a diagram schematically illustrating conventional diffusion combustion in a regenerative burner. Figure 2 (A) represents conventional diffusion combustion using the second nozzle on one side, Figure 2 (B) shows conventional diffusion combustion using a second nozzle on the other side. Figure 3 It is a diagram schematically illustrating the regenerative burner according to the first embodiment. Figure 3 (A) indicates a new type of diffusion combustion using the third nozzle on one side, Figure 3 (B) shows a new type of diffusion combustion using a third nozzle on the other side. Figure 4 It is a diagram schematically illustrating a regenerative burner according to a second embodiment. Figure 4(A) indicates a new type of diffusion combustion using the third nozzle on one side, Figure 4 (B) shows a new type of diffusion combustion using a third nozzle on the other side. Figure 5 This is a diagram schematically illustrating the features of the regenerative burner of the present invention. Figure 5 (A) indicates the maximum flame length when using the first nozzle for direct fire combustion. Figure 5 (B) represents the maximum flame length when conventional diffusion combustion using the second nozzle, Figure 5 (C) represents the minimum flame length when using the conventional diffusion combustion of the second nozzle, Figure 5 (D) represents the flame length when the new diffusion combustion using the third nozzle. DETAILED DESCRIPTION

[0011] Hereinafter, referring to the accompanying drawings, embodiments of the regenerative burners 10a and 10b of the present invention will be described. Figure 1 In the example, the left side is defined as one side and the right side is defined as the other side, sandwiching the center portion of the width direction of the furnace 1. Figure 1 In the diagram, the open valve state is indicated by a blank, and the closed valve state is indicated by a black fill.

[0012] [First embodiment] Reference Figures 1 to 3 and Figure 5 Next, the regenerative burners 10a and 10b according to the first embodiment will be described. Figure 1 This is a diagram schematically illustrating direct-fire combustion using the supply and exhaust portions 11 a and 11 b in the regenerative burners 10 a and 10 b . Figure 1 (A) indicates direct fire combustion using the first nozzle 21a on one side, Figure 1 (B) shows direct fire combustion using the first nozzle 21b on the other side. Figure 2 10a and 10b are diagrams schematically illustrating conventional diffusion combustion in the regenerative burners 10a and 10b. Figure 2 (A) represents conventional diffusion combustion using the second nozzle 22a on one side, Figure 2 (B) shows conventional diffusion combustion using the second nozzle 22b on the other side. Figure 3 It is a diagram schematically illustrating the regenerative burners 10a and 10b according to the first embodiment. Figure 3 (A) shows a new diffusion combustion method using the third nozzle 23a on one side. Figure 3 (B) shows a new diffusion combustion using the third nozzle 23b on the other side. Figure 5 It is a diagram schematically illustrating the features of the regenerative burners 10a and 10b of the present invention. Figure 5(A) represents the maximum flame length L1 during direct fire combustion using the first nozzles 21a and 21b. Figure 5 (B) represents the maximum flame length L2-1 during conventional diffusion combustion using the second nozzles 22a and 22b. Figure 5 (C) represents the minimum flame length L2-2 during conventional diffusion combustion using the second nozzles 22a and 22b. Figure 5 (D) shows the flame length L3 during the new diffusion combustion using the third nozzles 23a and 23b.

[0013] like Figure 1 As shown, for example, a pair of regenerative burners 10a and 10b are disposed opposite each other on the furnace wall 2 of the furnace 1. The regenerative burner 10a includes an air supply and exhaust section 11a including an air supply and exhaust port 14a, a first nozzle 21a, a second nozzle 22a, and a third nozzle 23a. For example, the second nozzles 22a and 22a are spaced apart, sandwiching the air supply and exhaust section 11a. The third nozzles 23a and 23a are disposed between the air supply and exhaust section 11a and the second nozzle 22a. The air supply and exhaust port 14a, the outlet of the second nozzle 22a, and the outlet of the third nozzle 23a are disposed flush with, for example, the wall 2 located on one side.

[0014] The other regenerative burner 10b also includes an air supply section 11b on the other side, including an air supply port 14b on the other side, a first nozzle 21b on the other side, a second nozzle 22b on the other side, and a third nozzle 23b on the other side. For example, a pair of second nozzles 22b, 22b on the other side are spaced apart, sandwiching the air supply section 11b on the other side, and a pair of third nozzles 23b, 23b on the other side are disposed between the air supply section 11b and the second nozzle 22b on the other side. The air supply port 14b on the other side, the discharge port of the second nozzle 22b on the other side, and the discharge port of the third nozzle 23b on the other side are, for example, flush with the wall surface 2 located on the other side.

[0015] The supply and exhaust section 11a on one side has a heat storage body 12a disposed therein, and a first nozzle 21a disposed on the side closer to the furnace interior 3 than the heat storage body 12a on one side. The supply and exhaust section 11b on the other side also has a heat storage body 12b disposed therein, and a first nozzle 21b disposed on the side closer to the furnace interior 3 than the heat storage body 12b on the other side.

[0016] The first nozzle 21a, the second nozzle 22a, and the third nozzle 23a are each connected to a fuel supply pipe 41 that supplies fuel. The fuel supply pipe 41 is provided with a first valve 31a corresponding to the first nozzle 21a, a second valve 32a corresponding to the second nozzle 22a, and a third valve 33a corresponding to the third nozzle 23a. The first valve 31a, the second valve 32a, and the third valve 33a each adjust the amount of fuel supplied from the fuel supply pipe 41.

[0017] Similarly, the first nozzle 21b, the second nozzle 22b, and the third nozzle 23b are each connected to a fuel supply pipe 41 that supplies fuel. The fuel supply pipe 41 is provided with a first valve 31b corresponding to the first nozzle 21b, a second valve 32b corresponding to the second nozzle 22b, and a third valve 33b corresponding to the third nozzle 23b. The first valve 31b, the second valve 32b, and the third valve 33b each adjust the amount of fuel supplied from the fuel supply pipe 41. Fuel gases such as natural gas (town gas), propane, butane, hydrogen, and ammonia are used.

[0018] The second nozzle 22a on one side and the second nozzle 22b on the other side are respectively configured to discharge fuel along the flow direction of the combustion-supporting gas discharged from the supply and exhaust portion 11a on one side and the supply and exhaust portion 11b on the other side.

[0019] The third nozzle 23a on one side and the third nozzle 23b on the other side are respectively configured to discharge fuel obliquely toward the flow of the combustion-supporting gas discharged from the supply and exhaust portion 11a on one side and the supply and exhaust portion 11b on the other side. In this way, the discharged fuel is diffused in the furnace 3 within a narrower range than the conventional diffusion combustion and burned in a state with good mixing properties, and the flame generated by the new diffusion combustion is made ( Figure 5 (D) is formed in a narrow range, so the flame length ( Figure 5 The flame length (F3) shown in (D) is shorter than that produced by conventional diffusion combustion.

[0020] A combustion-supporting gas supply pipe 45 and an exhaust gas discharge pipe 46 are connected to the supply and exhaust section 11a on one side and the supply and exhaust section 11b on the other side. The combustion-supporting gas supply pipe 45 is equipped with a combustion-supporting gas valve 35a corresponding to the supply and exhaust section 11a on one side and a combustion-supporting gas valve 35b corresponding to the supply and exhaust section 11b on the other side. An air supply fan 51 is provided upstream of the combustion-supporting gas supply pipe 45, and combustion-supporting gas is supplied to the supply and exhaust sections 11a and 11b through the combustion-supporting gas supply pipe 45. The combustion-supporting gas can be, for example, air, but pure oxygen or an oxygen-containing mixed gas can also be used.

[0021] An exhaust fan 53 and a chimney 55 are provided on the downstream side of the exhaust gas discharge pipe 46. After the exhaust gas flows through the exhaust gas discharge pipe 46, it is discharged from the chimney 55. The exhaust gas discharge pipe 46 is provided with an exhaust valve 36a on one side corresponding to the supply and exhaust section 11a on one side, and an exhaust valve 36b on the other side corresponding to the supply and exhaust section 11b on the other side.

[0022] Next, the operation of the pair of regenerative burners 10a and 10b having the above-described structure will be described.

[0023] Although not shown, at the start of operation of the furnace 1, both the regenerative burners 10a and 10b are used simultaneously to heat the furnace 3 by burning fuel ejected from the first nozzles 21a and 21b and combustion-supporting gas supplied from the combustion-supporting gas supply pipe 45. Exhaust gas generated by the combustion is discharged through an exhaust port (not shown) provided in the furnace wall 2.

[0024] When the temperature inside the furnace 3 reaches or exceeds the fuel's ignition temperature (e.g., 800°C), a switch is made to regenerative combustion, in which the operation of one regenerative burner 10a is alternating with the operation of the other regenerative burner 10b. Specifically, during regenerative combustion, the regenerative burners 10a on one side perform combustion while the other regenerative burner 10b performs thermal storage, storing heat from the exhaust gas, and then the regenerative burners 10a on one side perform thermal storage, storing heat from the exhaust gas, while the other regenerative burners 10b perform combustion. As described below, during regenerative combustion, diffusion combustion (hereinafter referred to as "normal diffusion combustion") using the second nozzles 22a and 22b is typically performed.

[0025] Reference Figure 2 , conventional diffusion combustion in the regenerative burner 10a on one side and the regenerative burner 10b on the other side will be described.

[0026] exist Figure 2 In (A), fuel is discharged from the second nozzle 22a by opening the second valve 32a on one side, and the discharged fuel is widely diffused within the furnace 3. The fuel diffused within the furnace 3 encounters the combustion-supporting gas supplied from the supply and exhaust section 11a on one side by opening the combustion-supporting gas valve 35a on one side, causing the regenerative burner 10a on one side to perform normal diffusion combustion. Consequently, the second nozzle 22a on one side generates normal diffusion combustion at a position away from the supply and exhaust section 11a on one side.

[0027] exist Figure 2In (B), the second valve 32b is opened, allowing fuel to be discharged from the second nozzle 22b on the other side. The discharged fuel diffuses widely within the furnace 3. The fuel diffused within the furnace 3 encounters the combustion-supporting gas supplied from the supply and exhaust section 11b on the other side by opening the combustion-supporting gas valve 35b on the other side. This causes the regenerative burner 10b on the other side to perform normal diffusion combustion. Consequently, normal diffusion combustion occurs at the second nozzle 22b on the other side, at a position away from the supply and exhaust section 11b on the other side.

[0028] Furthermore, in normal diffusion combustion, the temperature inside the furnace 3 is higher than the ignition temperature of the fuel, so the fuel ejected from the second nozzles 22a and 22b spontaneously ignites when encountering the combustion-supporting gas supplied from the supply and exhaust ports 11a and 11b.

[0029] Therefore, in the normal diffusion combustion using the second nozzles 22 a and 22 b , the fuel supplied into the furnace 3 burns while diffusing widely in the furnace 3 , forming a second flame F2 generated by the diffusion combustion at various locations in the furnace 3 . Figure 2 The second flame F2 shown is also Figure 1 The flame F1 generated by the direct combustion method shown is formed in an area that is not reached by the first flame F1, thereby heating the workpiece (not shown) in the furnace 3. Therefore, heating by conventional diffusion combustion can heat the furnace 3 over a wide range. In conventional diffusion combustion, the flame temperature is low, thereby suppressing nitrogen oxide (NOx) emissions.

[0030] like Figure 2 As shown in (A), during the period when the regenerative burner 10a on one side performs conventional diffusion combustion, the regenerative burner 10b on the other side performs heat storage operation, as shown in FIG. Figure 2 As shown in (B), while the regenerative burner 10a on one side is performing the heat storage operation, the regenerative burner 10b on the other side is performing the normal diffusion combustion.

[0031] The heat storage operation in the heat storage burners 10a and 10b will be described. In the heat storage operation, the heat of the exhaust gas generated by the heat storage burners 10a and 10b is stored. Figure 2In (A), the exhaust gas generated by conventional diffusion combustion in the regenerative burner 10a on one side is drawn into the other supply and exhaust section 11b by opening the other exhaust valve 36b in the other regenerative burner 10b on the other side and being drawn by the exhaust fan 53. As the exhaust gas passes through the other supply and exhaust section 11b, the other regenerative element 12b disposed in the other supply and exhaust section 11b absorbs heat from the exhaust gas, thereby storing heat in the other regenerative element 12b. This heat stored in the other regenerative element 12b preheats the combustion-supporting gas as it passes through the other regenerative element 12b during the subsequent combustion in the other regenerative burner 10b.

[0032] Likewise, in Figure 2 In (B), the exhaust gas generated by the conventional diffusion combustion of the regenerative burner 10b on the other side is drawn into the supply and exhaust section 11a on one side by opening the exhaust valve 36a on one side of the regenerative burner 10a and being sucked by the exhaust fan 53. As the exhaust gas passes through the supply and exhaust section 11a on one side, the regenerative element 12a on one side, provided in the supply and exhaust section 11a on one side, absorbs heat from the exhaust gas, thereby storing heat in the regenerative element 12a on one side. The heat stored in the regenerative element 12a on one side preheats the combustion-supporting gas as it passes through the regenerative element 12a on one side during combustion in the subsequent regenerative burner 10a on the other side. The opening and closing operations of the various valves 31a, 31b, 32a, 32b, 33a, 33b, 35a, 35b, 36a, and 36b are controlled by a control unit (not shown).

[0033] When the minimum flame length required in regenerative combustion is longer than that in conventional diffusion combustion ( Figure 5 (C) shows L2-2) When the flame length is shorter, use direct flame combustion. Figure 1 , the direct-fire combustion in the regenerative burner 10a on one side and the regenerative burner 10b on the other side will be described.

[0034] like Figure 1 As shown in (A), the first valve 31a and the combustion-supporting gas valve 35a on one side are opened, while the other valves 31b, 32a, 32b, 33a, and 33b, as well as the combustion-supporting gas valve 35b on the other side, are closed. This premixes the fuel ejected from the first nozzle 21a on one side and the combustion-supporting gas supplied to the supply and exhaust section 11a on one side. This premixed direct-fire combustion generates a first flame F1 on the one side with high combustion efficiency and linearity.

[0035] Likewise, Figure 1As shown in (B), the other side first valve 31b and the other side combustion-supporting gas valve 35b are opened, while the other valves 31a, 32a, 32b, 33a, 33b and the one side combustion-supporting gas valve 35a are closed. This premixes the fuel ejected from the other side first nozzle 21b and the combustion-supporting gas supplied to the other side supply and exhaust section 11b. This premixed direct-fire combustion forms the other side first flame F1, which has high combustion efficiency and a straight trajectory.

[0036] When the flame length required in regenerative combustion is between the minimum flame length in conventional diffusion combustion ( Figure 5 (C) is shown as L2-2) and the maximum flame length in the above direct fire combustion ( Figure 5 (A) shows the gap between L1) and the new diffusion combustion. Figure 3 , the novel diffusion combustion in the regenerative burner 10a on one side and the regenerative burner 10b on the other side will be described.

[0037] exist Figure 3 In (A), the third valve 33a on one side is opened, so that fuel is ejected from the third nozzle 23a on one side, and the ejected fuel is diffused in the furnace 3 within a narrower range than in the conventional diffusion combustion described above. The diffused fuel meets the combustion-supporting gas supplied from the supply and exhaust section 11a on one side by opening the combustion-supporting gas valve 35a on one side, thereby forming a flame generated by the new diffusion combustion in a narrow range in the regenerative burner 10a on one side ( Figure 5 Therefore, the third nozzle 23a on one side generates a new type of diffusion combustion at a position closer to the supply and exhaust portion 11a on one side than the conventional diffusion combustion, and the new type of diffusion combustion forms a flame length shorter than the flame length generated by the conventional diffusion combustion ( Figure 5 (D) is shown as F3).

[0038] exist Figure 3 In (B), the third valve 33b on the other side is opened, so that fuel is ejected from the third nozzle 23b on the other side. The ejected fuel diffuses in the furnace 3 within a narrower range than in the conventional diffusion combustion described above. The diffused fuel meets the combustion-supporting gas supplied from the supply and exhaust section 11b on the other side by opening the combustion-supporting gas valve 35b on the other side, thereby forming a flame generated by the new diffusion combustion in a narrow range in the regenerative burner 10b on the other side ( Figure 5 Therefore, the third nozzle 23b on the other side generates a new type of diffusion combustion at a position closer to the supply and exhaust portion 11b on the other side than the conventional diffusion combustion, and the new type of diffusion combustion forms a flame length shorter than the flame length generated by the conventional diffusion combustion ( Figure 5 (D) is shown as F3).

[0039] Furthermore, in the new diffusion combustion, the temperature inside the furnace 3 is also higher than the ignition temperature of the fuel. Therefore, the fuel ejected from the third nozzles 23a and 23b spontaneously ignites when it encounters the combustion-supporting gas supplied from the supply and exhaust ports 11a and 11b.

[0040] Therefore, in the novel diffusion combustion using the third nozzles 23a and 23b, the fuel supplied into the furnace 3 is diffused within the furnace 3 within a narrower range than in conventional diffusion combustion and combusted in a well-mixed state, thereby forming a third flame F3 generated by the novel diffusion combustion at various locations within the furnace 3. In the novel diffusion combustion, the flame temperature is lowered, similarly to conventional diffusion combustion, thereby suppressing nitrogen oxide (NOx) emissions.

[0041] Same as the case of conventional diffusion combustion, e.g. Figure 3 As shown in (A), while the regenerative burner 10a on one side performs the new diffusion combustion, the regenerative burner 10b on the other side performs the heat storage operation based on the regenerative body 12b on the other side. The heat stored in the regenerative body 12b on the other side preheats the combustion-supporting gas when the combustion-supporting gas passes through the regenerative body 12b on the other side when the regenerative burner 10b on the other side burns. In addition, as Figure 3 As shown in (B), while the heat storage burner 10b on the other side is performing the new diffusion combustion, the heat storage burner 10a on one side performs a heat storage action based on the heat storage body 12a on one side. The heat stored in the heat storage body 12a on one side is used to preheat the combustion-supporting gas when the combustion-supporting gas passes through the heat storage body 12a on one side when the next heat storage burner 10a on the side burns.

[0042] Reference Figure 5 , the difference in flame length between the regenerative burners 10a and 10b of the present invention will be described.

[0043] like Figure 5 As shown in (A), the first flame F1 during direct fire combustion using the first nozzles 21a and 21b forms a maximum flame length L1. Figure 5 As shown in (B), the second flame F2 during conventional diffusion combustion using the second nozzles 22a and 22b forms a maximum flame length L2-1. Figure 5 As shown in (C), the second flame F2 during conventional diffusion combustion using the second nozzles 22a and 22b forms a minimum flame length L2-2. Figure 5 As shown in FIG. 5 (D), the third flame F3 in the novel diffusion combustion using the third nozzles 23a and 23b forms a flame length L3.

[0044] exist Figure 5In the first flame F1 produced by direct fire combustion shown in (A), the flame length can also be changed by adjusting the combustion amount, but the variable range of the flame length is small and the maximum is only limited to the maximum flame length L1. The second flame F2 produced by conventional diffusion combustion can be Figure 5 The first flame F1 shown in (A) has a wide range of flame length changes, with Figure 5 The maximum flame length L2-1 shown in (B) Figure 5 The flame length range of the minimum flame length L2-2 shown in (C). Figure 5 The maximum flame length L1 of the direct fire combustion shown in (A) is Figure 5 There is a blank flame length between the minimum flame length L2-2 of conventional diffusion combustion shown in (C).

[0045] In the novel diffusion combustion method, the discharged fuel diffuses within the furnace 3 within a narrower range than in conventional diffusion combustion and burns in a well-mixed state. Consequently, a flame length L3 is formed that is shorter than the flame length produced by conventional diffusion combustion. The flame length L3 of the third flame F3 produced by the novel diffusion combustion is configured to include the minimum flame length L2-2 of the second flame F2 produced by conventional diffusion combustion. Furthermore, the flame length L3 is configured to include the maximum flame length L1 of the first flame F1 produced by direct-fire combustion. In other words, the fuel flow rate adjustment range achieved by the third valves 33a and 33b is configured such that the flame length L3 of the third flame F3 produced by the third nozzles 23a and 23b includes the maximum flame length L1 of the first flame F1 produced by the first nozzles 21a and 21b and the minimum flame length L2-2 of the second flame F2 produced by the second nozzles 22a and 22b. Therefore, the third flame F3 generated by the novel diffusion combustion forms an intermediate flame length L3, which fills the gap between the maximum flame length L1 of the first flame F1 generated by direct-fire combustion and the minimum flame length L2-2 of the second flame F2 generated by conventional diffusion combustion. Thus, the novel diffusion combustion can fill the gap in flame length with an intermediate flame length L3 between the maximum flame length L1 generated by direct-fire combustion and the minimum flame length L2-2 generated by conventional diffusion combustion.

[0046] Therefore, by using the new diffusion combustion of the third nozzles 23a and 23b, a flame length L3 that is intermediate between the short flame length produced by the direct fire combustion of the first nozzles 21a and 21b and the long flame length produced by the conventional diffusion combustion of the second nozzles 22a and 22b can be formed. Without enlarging the first nozzles 21a and 21b, the temperature distribution in the furnace can be adjusted while suppressing the emission of nitrogen oxides (NOx).

[0047] [Second embodiment] Reference Figure 4 Next, the regenerative burners 10a and 10b according to the second embodiment will be described. Figure 4 (A) is a cross-sectional view of the regenerative burners 10a and 10b according to the second embodiment, schematically illustrating a novel diffusion combustion using the third nozzle 23a on one side. Figure 4 (B) is a cross-sectional view of the regenerative burners 10a and 10b according to the second embodiment, schematically illustrating the new diffusion combustion using the third nozzle 23b on the other side.

[0048] like Figure 4 As shown, the third nozzle 23a on one side and the third nozzle 23b on the other side are respectively located near the supply and exhaust section 11a on one side and the supply and exhaust section 11b on the other side. At the same time, the third nozzle 23a on one side and the third nozzle 23b on the other side are respectively configured to discharge fuel along the flow direction of the combustion-supporting gas discharged from the supply and exhaust section 11a on one side and the supply and exhaust section 11b on the other side.

[0049] exist Figure 4 In (A), the third valve 33a is opened, allowing the fuel ejected from the third nozzle 23a to flow along the direction of the combustion-supporting gas. The ejected fuel diffuses within the furnace 3 within a narrower range than during conventional diffusion combustion. The diffused fuel encounters the combustion-supporting gas supplied from the supply and exhaust section 11a by opening the combustion-supporting gas valve 35a, thereby enabling the regenerative burner 10a to perform a novel diffusion combustion. Consequently, the third nozzle 23a generates a novel diffusion combustion at a position closer to the supply and exhaust section 11a than during conventional diffusion combustion.

[0050] exist Figure 4 In (B), the third valve 33b on the other side is opened, allowing the fuel ejected from the third nozzle 23b on the other side to flow along the direction of the combustion-supporting gas. This ejected fuel diffuses within the furnace 3 within a narrower range than during conventional diffusion combustion. The diffused fuel encounters the combustion-supporting gas supplied from the other supply and exhaust section 11b by opening the combustion-supporting gas valve 35b on the other side, thereby causing the regenerative burner 10b on the other side to perform a novel diffusion combustion. Consequently, the third nozzle 23b on the other side generates a novel diffusion combustion at a position closer to the supply and exhaust section 11b than during conventional diffusion combustion.

[0051] Furthermore, similarly to the first embodiment, the temperature inside the furnace 3 is higher than the ignition temperature of the fuel. Therefore, the fuel ejected from the third nozzles 23a and 23b spontaneously ignites when it encounters the combustion-supporting gas supplied from the supply and exhaust ports 11a and 11b.

[0052] In the new diffusion combustion of the second embodiment, the fuel supplied to the furnace 3 is diffused in the furnace 3 and burned in a well-mixed state within a narrower range than in the conventional diffusion combustion, forming a third flame F3 generated by the new diffusion combustion at various locations in the furnace 3. Therefore, by using the new diffusion combustion of the third nozzles 23a and 23b, a flame length L3 can be formed that is intermediate between the short flame length generated by the direct fire combustion of the first nozzles 21a and 21b and the long flame length generated by the conventional diffusion combustion of the second nozzles 22a and 22b. Without enlarging the first nozzles 21a and 21b, the temperature distribution in the furnace can be adjusted while suppressing the emission of nitrogen oxides (NOx). Moreover, unlike the first embodiment ( Figure 3 Compared to the Figure 3 The flame length shown is long. As a result, the adjustment range of the flame length can be moved along the length side, which can expand the application range.

[0053] Although the specific embodiments and numerical values ​​of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

[0054] In the above embodiment, the example illustrates the use of direct-fire combustion, conventional diffusion combustion, and novel diffusion combustion by opening any one of the first valves 31a, 31b, second valves 32a, 32b, and third valves 33a, 33b, which function as on-off valves (while the remaining valves are closed). However, the first valves 31a, 31b, second valves 32a, 32b, and third valves 33a, 33b may each be a regulating valve capable of adjusting the valve opening, thereby varying the ratio of the discharge flow rate from the first nozzles 21a, 21b, the discharge flow rate from the second nozzles 22a, 22b, and the discharge flow rate from the third nozzles 23a, 23b. This allows the third flame F3 generated by the novel diffusion combustion to have an appropriate flame length L3, which is between the maximum flame length L1 generated by direct-fire combustion and the minimum flame length L2-2 generated by conventional diffusion combustion. This allows the formation of an intermediate flame length L3 by novel diffusion combustion using the third nozzles 23a and 23b, and allows the temperature distribution in the furnace to be adjusted while suppressing nitrogen oxide (NOx) emissions without increasing the size of the first nozzles 21a and 21b.

[0055] The aforementioned novel diffusion combustion method discloses a method in which only the third valve 33a or 33b is opened and the third nozzle 23a or 23b is used to achieve this. However, it is also possible to open both the first valve 31a or 31b and the third valve 33a or 33b, allowing fuel to be ejected from both the first nozzle 21a or 21b and the third nozzle 23a or 23b. This method can produce a newer type of combustion that combines the novel diffusion combustion with direct-fire combustion, resulting in a flame with a higher temperature than the novel diffusion combustion described above. Furthermore, the ejection of fuel from the first nozzle 21a or 21b and the third nozzle 23a or 23b can occur simultaneously or with slightly staggered timing.

[0056] In the above embodiment, the regenerative burners 10a and 10b are provided pre-equipped with the supply and exhaust sections 11a and 11b, the first nozzles 21a and 21b, the second nozzles 22a and 22b, and the third nozzles 23a and 23b. However, existing regenerative burners 10a and 10b equipped with the supply and exhaust sections 11a and 11b, the first nozzles 21a and 21b, and the second nozzles 22a and 22b can also be retrofitted to add the new diffusion combustion system including the third nozzles 23a and 23b. This makes it easy to add the new diffusion combustion system to existing regenerative burners 10a and 10b.

[0057] A summary of the present invention and embodiments follows.

[0058] The regenerative burners 10a and 10b according to one embodiment of the present invention are characterized by comprising: The supply and exhaust parts 11a and 11b supply combustion-supporting gas and discharge exhaust gas through the internally arranged heat storage bodies 12a and 12b; The first nozzles 21a and 21b are disposed inside the air supply and exhaust sections 11a and 11b and discharge fuel; second nozzles 22a and 22b, which are separated from the supply and exhaust parts 11a and 11b and discharge the fuel along the flow direction of the combustion-supporting gas supplied from the supply and exhaust parts 11a and 11b; and The third nozzles 23a and 23b are disposed between the supply and exhaust sections 11a and 11b and the second nozzles 22a and 22b, and discharge the fuel to the combustion-supporting gas supplied from the supply and exhaust sections 11a and 11b.

[0059] According to the above structure, by using the new diffusion combustion of the third nozzles 23a and 23b, a flame length L3 that is intermediate between the short flame length generated by the direct fire combustion of the first nozzles 21a and 21b and the long flame length generated by the conventional diffusion combustion of the second nozzles 22a and 22b can be formed. Without enlarging the first nozzles 21a and 21b, the temperature distribution in the furnace can be adjusted while suppressing the emission of nitrogen oxides (NOx).

[0060] In addition, in the regenerative burners 10a and 10b according to one embodiment, The third nozzles 23a and 23b are configured to discharge the fuel obliquely toward the flow of the combustion-supporting gas.

[0061] According to the above embodiment, in order to make the ejected fuel diffuse in the furnace 3 within a range narrower than that of conventional diffusion combustion and burn in a well-mixed state, the flame generated by the new diffusion combustion is formed within a narrow range, so the flame length L3 generated by the new diffusion combustion is shorter than the flame length generated by conventional diffusion combustion.

[0062] In addition, in the regenerative burners 10a and 10b according to one embodiment, On the fuel supply pipe 41 that supplies the fuel to the first nozzle 21a, 21b, the second nozzle 22a, 22b and the third nozzle 23a, 23b, there are provided first valves 31a, 31b, second valves 32a, 32b and third valves 33a, 33b for respectively adjusting the supply amount of the fuel, so that the flame length L3 of the third flame F3 generated by the third nozzle 23a, 23b can be adjusted to: the maximum flame length L1 of the first flame F1 generated by the first nozzle 21a, 21b and the minimum flame length L2-2 of the second flame F2 generated by the second nozzle 22a, 22b.

[0063] According to the above embodiment, the missing flame length can be filled by the intermediate flame length L3 between the maximum flame length L1 generated by direct fire combustion and the minimum flame length L2-2 generated by conventional diffusion combustion.

[0064] In addition, in the regenerative burners 10a and 10b according to one embodiment, The fuel is ejected from the first nozzles 21 a and 21 b and the third nozzles 23 a and 23 b.

[0065] According to the above embodiment, by ejecting fuel from both the first nozzle 21a or 21b and the third nozzle 23a or 23b, a new type of combustion that is a mixture of new diffusion combustion and direct combustion can be formed, and a flame having a higher temperature than the new diffusion combustion can be formed.

[0066] In another embodiment, the regenerative burners 10a and 10b are modified as follows: The regenerative burners 10a and 10b are provided with: supply and exhaust parts 11a and 11b, which supply combustion-supporting gas and discharge exhaust gas through regenerative bodies 12a and 12b provided therein; first nozzles 21a and 21b, which are disposed inside the air supply and exhaust portions 11a and 11b and discharge fuel; and The second nozzles 22a and 22b are separated from the supply and exhaust parts 11a and 11b and discharge fuel along the flow direction of the combustion-supporting gas supplied from the supply and exhaust parts 11a and 11b. Its characteristic is that third nozzles 23a and 23b are added relative to the regenerative burners 10a and 10b, and the third nozzles 23a and 23b are arranged between the supply and exhaust parts 11a and 11b and the second nozzles 22a and 22b, and discharge the fuel to the combustion-supporting gas supplied from the supply and exhaust parts 11a and 11b.

[0067] According to the above method, the above-mentioned novel diffusion combustion can be easily added to the existing regenerative burners 10a and 10b. Explanation of symbols

[0068] 1 furnace; 2 furnace wall; 3. Inside the furnace; 10a, 10b regenerative burners; 11a, 11b supply and exhaust parts; 12a, 12b heat storage body; 14a, 14b supply and exhaust ports; 21a, 21b first nozzle; 22a, 22b second nozzle; 23a, 23b third nozzle; 31a, 31b first valve; 32a, 32b second valve; 33a, 33b third valve; 35a, 35b combustion-supporting gas valve; 36a, 36b wastegate valves; 41 fuel supply pipe; 45 combustion-supporting gas supply pipe; 46 exhaust gas discharge pipe; 51 air supply fan; 53 exhaust fan; 55 chimney; F1 First Flame; F2 second flame; F3 Third Flame; L1 Maximum flame length of the first flame; L2-1 Maximum flame length of the second flame; L2-2 Minimum flame length of the second flame; L3 Flame length of the third flame.

Claims

1. A regenerative burner, characterized in that: have: The supply and exhaust part supplies combustion-supporting gas and discharges exhaust gas through the internally arranged heat storage body; a first nozzle disposed inside the air supply and exhaust portion and discharging fuel; a second nozzle disposed separately from the supply and exhaust portion and configured to discharge the fuel along a flow direction of the combustion-supporting gas supplied from the supply and exhaust portion; and The third nozzle is disposed between the supply and exhaust portion and the second nozzle, and discharges the fuel to the combustion-supporting gas supplied from the supply and exhaust portion.

2. The regenerative burner according to claim 1, characterized in that: The third nozzle is configured to discharge the fuel obliquely toward the flow of the combustion-supporting gas.

3. The regenerative burner according to claim 1, characterized in that: A first valve, a second valve and a third valve are provided on the fuel supply pipe that supplies the fuel to the first nozzle, the second nozzle and the third nozzle, respectively adjusting the supply amount of the fuel, so that the flame length of the third flame generated by the third nozzle can be adjusted to include the maximum flame length of the first flame generated by the first nozzle and the minimum flame length of the second flame generated by the second nozzle.

4. The regenerative burner according to claim 1, characterized in that: The fuel is discharged from the first nozzle and the third nozzle.

5. A method for modifying a regenerative burner. The regenerative burner comprises: an air supply and exhaust portion for supplying combustion-supporting gas and discharging exhaust gas via a regenerative body provided inside; a first nozzle disposed inside the air supply and exhaust portion and discharging fuel; and The second nozzle is arranged separately from the supply and exhaust portion and discharges fuel along the flow direction of the combustion-supporting gas supplied from the supply and exhaust portion. It is characterized in that A third nozzle is added to the regenerative burner. The third nozzle is disposed between the supply and exhaust portion and the second nozzle and discharges the fuel to the combustion-supporting gas supplied from the supply and exhaust portion.

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