Gas atomizing burner

Abstract

To prevent the elongation of a flame while suppressing the lowering of a flow rate of an oxidant-containing gas to be supplied by favorably suppressing the intrusion of powdery dust derived from a heated object, and liquid fuel which is not atomized out of atomized liquid fuel into an oxidant-containing gas circulation path.SOLUTION: A gas atomization burner comprises an externally-surrounding cylinder part 31 functioning as an oxidant containing gas circulation path R1 in which an oxidant containing gas circulates between a fuel circulation cylinder part 30 and itself in a form for externally surrounding the fuel circulation cylinder part 30, and a cylindrical body 10 which can be inserted into the oxidant containing gas circulation path R1 has a plurality of spiral grooves 10a for guiding the oxidant containing gas to a tip by making it swirl along a cylinder external peripheral region. The gas atomization burner also comprises a compressor for pressure-sending either of combustion air or an air-fuel mixture in which the combustion air and gas fuel are mixed to the oxidant containing gas circulation path R1 as the oxidant containing gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas atomizing burner that includes a fuel flow tube portion that serves as a fuel flow path through which atomized mixed fuel, which is a mixture of atomized liquid fuel atomized from liquid fuel and gas fuel, flows, and a nozzle portion that sprays the atomized mixed fuel flowing through the fuel flow path at the tip of the fuel flow path. [Background technology]

[0002] This gas atomizing burner is used in gas atomizing burners that atomize and burn liquid fuel with gas fuel. The gas atomizing burner is used to heat objects to be heated, for example, in lime kilns for papermaking, glass melting furnaces, etc. Various liquid fuels are used, such as heavy oil, light oil, kerosene, and recycled oil made from recycled waste oil. By using liquid fuel, which is cheaper than gas fuel, as part of the fuel, it is possible to reduce energy costs when heating objects to be heated, such as lime kilns and glass melting furnaces (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-139704 Summary of the Invention [Problem to be solved by the invention]

[0004] Although illustrations and explanations are omitted from the technology disclosed in Patent Document 1, a typical gas atomizing burner has an outer casing that surrounds a burner nozzle that sprays atomized mixed fuel that is a mixture of atomized liquid fuel and gas fuel, and adopts a configuration in which primary combustion air is supplied via a combustion air flow path formed between the burner nozzle and the outer casing. However, when the above-mentioned gas atomizing burner is put into practical use, there is a problem that dust particles such as lime from the object to be heated, and liquid fuels such as heavy oil and recycled oil that are not atomized, enter and accumulate in the combustion air flow path, resulting in an insufficient amount of primary combustion air being supplied through the combustion air flow path. In this way, when the amount of primary combustion air supplied from the combustion air supply passage is insufficient, the atomized mixed fuel injected from the gas atomizing burner does not burn sufficiently immediately after injection due to the lack of combustion air, and is instead burned by the secondary combustion air supplied to the inside of the lime kiln or glass melting furnace. As a result, the flame becomes longer in the axial direction of the burner nozzle, and the temperature rise effect on the base end of the burner nozzle is not sufficient, leaving room for improvement.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a gas atomizing burner that can effectively suppress the intrusion of dust from the object to be heated and the liquid fuel that is not atomized among the atomized liquid fuel into the oxidizer-containing gas flow path, thereby suppressing a decrease in the flow rate of the oxidizer-containing gas supplied while preventing the flame from becoming long. [Means for solving the problem]

[0006] The gas atomizing burner for achieving the above object is a gas atomizing burner including a fuel flow tube portion which serves as a fuel flow path through which atomized mixed fuel, which is a mixture of atomized liquid fuel atomized from liquid fuel and gas fuel, flows, and a nozzle portion at the tip of the fuel flow path which injects the atomized mixed fuel flowing through the fuel flow path, and the gas atomizing burner has the following characteristic configuration: an outer surrounding cylindrical portion that surrounds the fuel flow cylindrical portion and serves as an oxidant-containing gas flow path for flowing an oxidant-containing gas between the outer surrounding cylindrical portion and the fuel flow cylindrical portion; A cylindrical body that can be fitted into the oxidant-containing gas flow passage has a plurality of spiral grooves that swirl the oxidant-containing gas along the outer periphery of the cylinder and guide it to the tip. and a tip-side expanded diameter portion having an outer diameter larger than that of a base-side portion on the base end side in the axial direction. Having and being equipped with The oxidant-containing gas is either combustion air or a mixture of the combustion air and the gas fuel, and the compressor is configured to compress the air into the oxidant-containing gas passage.、 The plurality of spiral grooves are formed continuously from the base end portion to the tip end expanded diameter portion. It's at the point.

[0007] The gas atomizing burner to achieve the above purpose is as follows: A gas atomizing burner comprising: a fuel flow tube portion serving as a fuel flow path through which atomized mixed fuel, which is a mixture of atomized liquid fuel atomized by atomizing liquid fuel and gas fuel, flows; and a nozzle portion at a tip of the fuel flow path for injecting the atomized mixed fuel flowing through the fuel flow path, an outer surrounding cylindrical portion that surrounds the fuel flow cylindrical portion and serves as an oxidant-containing gas flow path for flowing an oxidant-containing gas between the outer surrounding cylindrical portion and the fuel flow cylindrical portion; a cylindrical body that can be fitted into the oxidant-containing gas flow passage, the cylindrical body having a plurality of spiral grooves that swirl the oxidant-containing gas along the outer periphery of the cylindrical body and guide the gas to the tip; a compressor that pressure-feeds either combustion air or a mixture of the combustion air and the gas fuel as the oxidant-containing gas into the oxidant-containing gas passage; The aforementioned Cylindrical body a plurality of swirl vanes for swirling the oxidant-containing gas flowing through the oxidant-containing gas passage, the swirl vanes being provided on a base end side of the cylindrical body in the axial direction of the oxidant-containing gas passage; The swirling direction of the oxidant-containing gas caused by the plurality of spiral grooves in the cylindrical body is opposite to the swirling direction of the oxidant-containing gas caused by the plurality of swirling blades.

[0008] According to the above characteristic configuration, first, the compressor pressurizes combustion air or a mixture of combustion air and gas fuel as oxidant-containing gas into the oxidant-containing gas flow path, and the oxidant-containing gas that flows through the oxidant-containing gas flow path at high pressure is sprayed from its tip at a relatively high speed, thereby effectively preventing dust from the object to be heated and liquid fuel that is not atomized from the atomized mixed fuel from entering the oxidant-containing gas flow path. However, when a configuration is adopted in which the oxidant-containing gas is injected at high pressure as described above, the speed at which the oxidant-containing gas is ejected from the tip increases, which may result in a longer flame. In contrast, in the above-described characteristic configuration, a cylindrical body having a plurality of spiral grooves that swirl the oxidant-containing gas along the outer periphery of the tube and guide it to the tip is inserted into the oxidant-containing gas flow path. Therefore, by swirling the oxidant-containing gas flowing through the oxidant-containing gas flow path, the overall flow velocity of the oxidant-containing gas in the axial direction of the outer cylindrical portion can be reduced, and the formation of a long flame can be effectively prevented. Furthermore, the swirling flow can effectively blow away dust from the object to be heated, which may accumulate in the oxidant-containing gas passage, and the liquid fuel that is not atomized in the atomized mixed fuel. As a result of the above, a gas atomizing burner can be realized that effectively prevents dust from the object to be heated and the non-atomized liquid fuel from entering the oxidant-containing gas flow path, thereby preventing a decrease in the flow rate of the oxidant-containing gas being supplied while preventing the flame from becoming long.

[0009] According to the above characteristic configuration, the cylindrical body has a tip-side expanded diameter portion that is larger in diameter than the outer diameter of the base-side portion on the base-side, and the multiple spiral grooves are formed continuously from the base-side portion to the tip-side expanded diameter portion.Therefore, the flow rate of the oxidant-containing gas that passes directly through the space between the cylindrical body and the outer cylindrical portion to the outside can be reduced, and the ejection pressure of the oxidant-containing gas that is ejected to the outside as a swirling flow through the spiral grooves of the cylindrical body can be increased, thereby more effectively preventing dust from the object to be heated and liquid fuel that is not atomized from the atomized mixed fuel from entering the oxidant-containing gas flow path from the tip of the oxidant-containing gas flow path. Furthermore, mixing of the oxidizer-containing gas and the atomized mixed fuel immediately after ejection is further promoted, facilitating combustion and further shortening the flame. Furthermore, the cylindrical body may deform over time to a shape that makes it impossible to insert it into the oxidant-containing gas flow path due to deterioration over time. As described above, by expanding only the tip end in the axial direction of the cylinder, even if deformation over time occurs, it can be reused by performing cutting or the like only on the expanded tip end portion, thereby reducing the effort and time required for processing.

[0010] In addition, the inventors of the present invention discovered through experiments described below that by setting the swirling direction of the oxidant-containing gas by the multiple spiral grooves of the cylindrical body and the swirling direction of the oxidant-containing gas by the multiple swirling blades in opposite directions, it is possible to achieve even greater temperature rise immediately after ejection from the tip of the burner nozzle. That is, by adopting this knowledge, it is possible to more effectively achieve a shorter flame and a temperature rise near the tip of the burner nozzle when high-pressure injection is performed.

[0011] Further characteristic features of the gas atomizing burner are: When viewed in the direction of the cylindrical axis of the cylindrical body, The spiral grooves are arranged such that the angle of rotation from the base end to the tip end of the cylindrical body is set within a range of 20° to 60°.

[0012] The inventors of the present invention have experimentally confirmed that in the configuration described above, with regard to the spiral groove of the cylindrical body, the angle of rotation relative to the axis of the cylindrical body from the base end to the tip end of the cylindrical body is assumed to be such that a smaller angle will result in a longer flame and a larger angle will result in a shorter flame, by setting the angle to a range of 20° or more and 60° or less, it is possible to effectively shorten the flame and to effectively increase the temperature immediately after ejection, as will be described in the examples below. To add to the explanation, the inventors have experimentally confirmed that when the swirl angle is less than 20°, the effect of the swirl on the flame is extremely small, and when the swirl angle is more than 60°, the pressure loss becomes large and affects combustion.

[0014] Further characteristic features of the gas atomizing burner are: The compressor adjusts the pressure of the oxidant-containing gas flowing out from the plurality of spiral grooves to 60 kPaG or more and 150 kPaG or less.

[0015] The inventors experimentally confirmed that by setting the pressure of the oxidant-containing gas flowing out from the multiple spiral grooves to 60 kPaG or more and 150 kPaG or less, it is possible to effectively prevent dust from the heated object and non-atomized liquid fuel from the atomized mixed fuel from entering the oxidant-containing gas flow path, while also effectively suppressing flame misfires and long flames. Incidentally, when the oxidant-containing gas is pumped into the oxidant-containing gas passage at a low pressure of less than 60 kPaG, there is a risk that dust from the object to be heated or unatomized liquid fuel may enter the oxidant-containing gas passage and clog the passage. On the other hand, tests described below have confirmed that misfires occur when the pressure is higher than 150 kPaG (for example, 175 kPaG). [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view of a gas atomizing burner according to an embodiment of the present invention; [Figure 2] 1 is a plan view of a gas atomizing burner according to an embodiment of the present invention as viewed in the axial direction. FIG. [Figure 3] 1 is a perspective view of a main configuration of a gas atomizing burner according to an embodiment of the present invention. FIG. [Figure 4] FIG. 1 is a graph showing a combustion test of a gas atomizing burner according to an embodiment of the present invention. [Figure 5] FIG. 1 is a graph showing a combustion test of a gas atomizing burner according to an embodiment of the present invention. [Figure 6] FIG. 1 is a graph showing a combustion test of a gas atomizing burner according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The gas atomizing burner 100 according to an embodiment of the present invention effectively prevents dust particles from the object to be heated and non-atomized liquid fuel from entering the oxidizer-containing gas flow passage, thereby preventing a decrease in the flow rate of the oxidizer-containing gas being supplied while preventing the flame from becoming long. A gas atomizing burner equipped with the gas atomizing burner 100 atomizes liquid fuel such as heavy oil, light oil, kerosene, recycled oil made from recycled waste oil, etc. with gas fuel such as city gas 13A, mixes the atomized liquid fuel with gas fuel, and then sprays the atomized mixed fuel, which is a mixture of the gas fuel and the atomized liquid fuel, from the tip, and ignites the mixture with combustion air to form a flame. The gas atomizing burner is used in various furnaces, such as a glass melting furnace, a lime kiln for paper manufacturing, etc. The manner in which the gas atomizing burner is installed in the furnace is well known, so a detailed description and illustrations will be omitted and a brief description will be given. The furnace is provided with an air passage (not shown) along the furnace wall on the burner installation side for supplying secondary combustion air into the furnace. The gas atomizing burner 100 is provided below or within the air passage in the furnace wall, or within the combustion chamber of the furnace, to combust the sprayed atomized mixed fuel with the secondary combustion air supplied from the air passage.

[0018] As shown in Figures 1 and 2, the gas atomizing burner 100 is configured to include a fuel flow tube portion 30 having a fuel flow path 30a inside which atomized mixed fuel, which is a mixture of atomized liquid fuel and gas fuel, flows, and a nozzle portion 20 having a main ejection hole 21 at the tip of the fuel flow path 30a for ejecting the atomized mixed fuel flowing through the fuel flow path 30a in the direction of the axis P of the fuel flow tube portion 30, and a plurality of auxiliary ejection holes 22 arranged in a ring shape around the main ejection hole 21 when viewed in the direction of the fuel flow path axis P along the axis P of the fuel flow path 30a. Furthermore, the axis of each of the multiple secondary injection holes 22 is set in a direction that moves away radially from the axis P of the fuel flow path 30a of the fuel flow cylindrical portion 30 as it moves forward in the direction of the fuel flow path axis P, and the atomized mixed fuel injected from the secondary injection hole 22 has a fan-shaped configuration. In the gas atomizing burner 100, the size (cross-sectional area) of the main nozzle hole 21 provided in the nozzle section 20, the installation form of the auxiliary nozzle holes 22, the size (cross-sectional area) of each auxiliary nozzle hole 22, etc. can be designed appropriately, and by changing these, the length and thickness of the flame F that can be formed can be changed.

[0019] Now, in order to supply primary combustion air to the radially outside of the fuel flow cylindrical section 30, a first combustion air cylindrical section 31 (an example of an outer surrounding cylindrical section), a second combustion air cylindrical section 32, a third combustion air cylindrical section 33, a fourth combustion air cylindrical section 34, and a fifth combustion air cylindrical section 35 are arranged coaxially with the fuel flow cylindrical section 30 in the order listed from the radially inside. To further explain, the fourth combustion air cylindrical section 34 and the fifth combustion air cylindrical section 35 are configured as a single cylindrical body, and a first annular wall section 36 is provided at the tip thereof. A plurality of straight openings R3a are arranged in an annular shape around the axis P in the first annular wall section 36, and a primary straight combustion air passage R3 through which primary combustion air that moves straight in the direction of the axis P flows between the fourth combustion air cylindrical section 34 and the fifth combustion air cylindrical section 35 is communicated with the plurality of straight openings R3a. Furthermore, the first combustion air cylindrical section 31 and the second combustion air cylindrical section 32 are configured as a single cylindrical body, and a second annular wall section 37 is provided at the tip thereof. A plurality of swirl holes R2a are arranged annularly around the axis P in the second annular wall section 37, and a primary swirl combustion air passage R2, through which primary combustion air that forms a swirl flow swirling around the axis P flows, is connected between the first combustion air cylindrical section 31 and the second combustion air cylindrical section 32 as the plurality of swirl holes R2a. The straight apertures R3a and the swivel apertures R2a have generally flattened arc shapes. The straight apertures R3a are arranged such that the longitudinal direction of the flattened shape is aligned with the arrangement of the straight apertures R3a, and the swivel apertures R2a are arranged such that the longitudinal direction of the flattened shape is aligned with the arrangement of the swivel apertures R2a.

[0020] Furthermore, a primary swirl auxiliary combustion air passage R1 (an example of an oxidant-containing gas passage) is formed between the fuel passage tube 30 and the first combustion air passage tube 31 as a passage for primary combustion air that can prevent the intrusion of dust from the object to be heated and unatomized liquid fuel from the atomized mixed fuel. Primary combustion air compressed by a compressor (not shown) is pumped into the primary swirl auxiliary combustion air passage R1 so that the high-pressure, high-velocity primary combustion air can eject dust, liquid fuel, and other particles that have entered the passage. The pressure of the primary combustion air pumped by the compressor is set to 60 kPaG or more and 150 kPaG or less. The primary combustion air compressed by the compressor is in the range of 1% to 5% of the total combustion air (including primary and secondary) used in glass melting furnaces and lime kilns for papermaking. However, when the primary combustion air is compressed and fed at high pressure and velocity in this manner, the flame formed by the gas atomizing burner 100 becomes long, and there is a risk that the temperature rise at the base end of the flame may not be sufficient.

[0021] Therefore, a cylindrical body 10 that can be fitted between the fuel flow cylindrical section 30 and the first combustion air cylindrical section 31 is provided at the tip end between the fuel flow cylindrical section 30 and the first combustion air cylindrical section 31, and the cylindrical body 10 has multiple spiral grooves 10a that swirl the primary combustion air along the outer periphery of the cylindrical body 10 and lead it to the tip. This allows the primary combustion air to swirl, reducing the speed of the primary combustion air in the direction of the axis P and shortening the flame, which is expected to have a temperature rise effect on the base end of the flame. In this embodiment, the outer diameter L3 of the fuel flow cylindrical portion 30 is set to 60.5 mm, and the inner diameter L4 of the tip end of the first combustion air cylindrical portion 31 is set to 76.3 mm.

[0022] In this embodiment, the multiple spiral grooves 10a are recessed from the outer peripheral surface of the tubular body 10, and 16 of them are provided at equal intervals along the outer periphery of the tubular body 10. When viewed in the direction of the axis P, the rotation angle of each of the multiple spiral grooves 10a relative to the axis of the tubular body 10 from the base end to the tip end is set in the range of 20° to 60° (30° in this embodiment). The depth L5, width L6 and number of grooves of the spiral groove 10a can take various forms, as will be disclosed in the combustion test described later. Incidentally, a female screw portion Na is formed on the inner diameter portion on the base end side of the cylindrical body 10, and a male screw portion Nb is formed on the outer diameter portion on the tip end side of the fuel flow cylindrical portion 30, and the cylindrical body 10 is inserted and positioned in the primary swirl auxiliary combustion air flow path R1 with the two screwed together.

[0023] The cylindrical body 10 has a tip-side expanded diameter portion 10b whose diameter is larger than the outer diameter of the base-side portion 10c on the base-side in the direction along the axis P, and the multiple spiral grooves 10a are continuously formed from the base-side portion 10c to the tip-side expanded diameter portion 10b. By providing the tip-side expanded diameter portion 10b, the gap (radial gap) between the outer peripheral surface of the cylindrical body 10 and the outer peripheral surface of the first combustion air cylindrical portion 31 can be reduced, and the flow rate and flow velocity of the primary swirling auxiliary combustion air flowing out to the outside through the spiral grooves 10a can be increased. The cylindrical body 10 has a cylindrical shape and is provided with a tapered portion at the tip end (downstream in the flow direction of the combustion air), a tip end expanded portion 10b, and a base end portion 10c, which are provided successively in the order shown. The cylindrical body 10 is further provided to surround the nozzle portion 20. Furthermore, the tip end of the spiral groove 10a (downstream in the flow direction of the combustion air) is located between the tip end of the nozzle portion 20 and the tip end of the fuel flow cylindrical portion 30 in the axial direction, and is located between the fuel flow path 30a and the swirl opening R2a in the axial direction. In addition, in the direction along the axis P, the ratio of the length of the tip-side expanded diameter portion 10b to the length of the tubular body 10 is preferably about 10% or more and 30% or less, and is set to 10% in this embodiment. Also, the ratio (L7 / L8) of the outer diameter L7 (67.5 mm in this embodiment) of the tip-side expanded diameter portion 10b to the outer diameter L8 (58.0 mm in this embodiment) of the base-end portion 10c of the tubular body 10 is preferably about 110% or more and 116% or less, and is set to 116% in this embodiment.

[0024] A plurality of swirl vanes 11 for swirling the primary combustion air flowing through the primary swirl auxiliary combustion air passage R1 are provided on the base end side of the cylindrical body 10 in the axial direction, and the swirl vanes 11 are installed and the spiral grooves 10a are cut so that the swirl direction of the primary combustion air by the plurality of swirl vanes 11 is opposite to the swirl direction of the primary combustion air by the plurality of spiral grooves 10a of the cylindrical body 10. The swirl vanes 11 are formed to protrude radially outward from the outer circumferential surface of the fuel flow cylindrical portion 30.

[0025] [First combustion test] A first combustion test using the gas atomizing burner 100 according to the above embodiment will be described. In the first combustion test, a predetermined sample was placed in a furnace as an object to be heated and heated, and the sample was continuously supplied to positions ranging from 0 m to 50 m in the flow direction of the atomized mixed fuel, with the tip of the gas atomizing burner 100 (the tip of the cylindrical body 10) being set as the reference position, and was collected and checked two hours after firing under the following conditions. The cylindrical body 10 of the first nozzle used in the first combustion test had a width L6 of the spiral grooves 10a of 3 mm, a depth L5 of 4 mm, 20 grooves, and a total cross-sectional area of ​​the spiral grooves 10a of 240 mm2 as viewed in the axial direction of the cylindrical body 10. 2 The turning angle was set to 30°. The supply amount of heavy oil as atomized liquid fuel, which is the atomized mixed fuel, supplied through the fuel flow path 30a is 553.1 L / h, and the supply amount of city gas as gas fuel, which is the atomized mixed fuel, is 273 m 3The amount of secondary combustion air supplied into the furnace from sources other than the gas atomizing burner 100 was 5000 m 3 N / h. In addition, the combustion air as an oxidizer-containing gas supplied through the primary swirl auxiliary combustion air flow passage R1 has a head pressure of 125 kPaG at the tip of the cylindrical body 10 and a supply amount of 233 m 3 N / h. Samples of the types and particle sizes shown in Table 1 below were prepared and fired in separate combustions from the first to fifth combustions. Incidentally, the values ​​shown in Table 1 mean that, for example, a sample of 20 mm particle size from the first combustion contains 62 wt% CaO, 24 wt% Ca(CO3), 11 wt% Ca5(PO4)3(OH), 1.8 wt% Ca(OH)2, and 1.0 wt% MgO. As shown in Table 1, the test results showed that an average firing rate of 79.8% was achieved, which was almost sufficient to achieve the target firing rate of 80%. [Table 1]

[0026] [Second combustion test] A second combustion test using the gas atomizing burner 100 according to the above embodiment will be described. In the second combustion test, when the gas atomizing burner 100 is burned in a furnace, the head pressure at the tip of the burner nozzle (the tip of the cylindrical body 10) and the supply amount of combustion air as an oxidant-containing gas supplied through the primary swirl auxiliary combustion air flow path R1 are changed, and temperatures at seven predetermined points from the tip of the burner nozzle in the direction of flame formation to the exhaust port of the furnace are measured. The cylindrical body 10 of the second nozzle used in the second combustion test does not have a tip-side expanded diameter portion 10b. Except for the "standard" combustion test described later, the width L6 of the spiral groove 10a is 6 mm, the depth L5 is 4 mm, the number of grooves is 16, and the total cross-sectional area of ​​the spiral grooves as viewed in the axial direction of the cylindrical body 10 is 480 mm. 2 The turning angle was set to 45°. The supply amount of heavy oil as atomized liquid fuel, which is the atomized mixed fuel supplied through the fuel flow path 30a, is 440 L / h, and the supply amount of city gas as gas fuel, which is the atomized mixed fuel, is 210 m 3 N / h. The amount of secondary combustion air supplied to the furnace from sources other than the gas atomizing burner 100 was 7000 m 3 N / h.

[0027] In the second combustion test, in each legend, the amount of combustion air supplied into the furnace through the primary straight combustion air passage R3 was set to the same flow rate, the opening of the primary swirling combustion air passage R2 was set to 50% under normal conditions and adjusted to 20% to simulate blockage, and multiple combustion tests were conducted by adjusting the pressure loss in the primary swirling auxiliary combustion air passage R1 and the head pressure at the tip of the cylindrical body 10. The "target value" shown in the legend of Figure 4 is when the control valve opening of the primary swirling combustion air passage R2 is set to 50%, and the "standard" shown in the legend of Figure 4 is when the control valve opening is set to 20% to simulate blockage of the primary swirling combustion air passage R2 and a cylindrical body 10 without a spiral groove 10a is used, and the combustion test was conducted without supplying compressed air to the primary swirling auxiliary combustion air passage R1. In the "second nozzle (head pressure 60 kPaG)" shown in the legend of Figure 4, the control valve opening was set to 20% to simulate the blockage of the primary swirl auxiliary combustion air flow path R1, and the combustion air was supplied at a head pressure of 60 kPaG with a volume of 143 m 3 In the "second nozzle (head pressure 100 kPaG)" shown in the legend of Figure 4, the control valve opening was set to 20% to simulate blockage of the primary swirl auxiliary combustion air flow path R1, and the combustion air was supplied at a head pressure of 100 kPaG with a supply volume of 183 m 3 / h (assumed value). For the "second nozzle (head pressure 150 kPaG)" shown in the legend of Figure 4, the control valve opening is set to 20% to simulate blockage of the primary swirl auxiliary combustion air flow path R1, and the combustion air is supplied at a head pressure of 150 kPaG and a volume of 225 m 3 / h (estimated value).

[0028] In this second combustion test, the aim is to raise the temperature at the third point (third plot) that is the third distance from the tip of the burner nozzle above the "reference" temperature and approach the "target value" of approximately 720°C. As can be seen from Figure 4, in all cases where the second nozzle (head pressure 60 kPaG), second nozzle (head pressure 100 kPaG), or second nozzle (head pressure 150 kPaG) was used, no misfires occurred and good combustion was achieved, and the temperature at the third point (third plot) from the vicinity of the tip of the burner nozzle exceeded the "reference" temperature, indicating an improvement in combustion. Although not shown in the drawings, it has been confirmed through experiments that misfires occur when the head pressure is set to 175 kPaG or higher.

[0029] [Third combustion test] The third combustion test was carried out using a third nozzle and a fourth nozzle in which the conditions of the spiral groove 10a of the cylindrical body 10 were changed. In the third combustion test, similar to the second combustion test, when a gas atomizing burner 100 is burned in a furnace, the head pressure and supply amount of combustion air as an oxidizer-containing gas supplied through the primary swirl auxiliary combustion air flow path R1 at the tip of the burner nozzle (tip of the cylindrical body 10) are changed, and the temperature at seven specified points from the tip of the burner nozzle in the direction of flame formation to the exhaust outlet of the furnace is measured. The cylindrical body 10 of the second nozzle used in the third combustion test does not have the tip-side expanded diameter portion 10b. Except for the "standard" combustion test described later, the third nozzle according to the test results in FIG. 5 has a width L6 of 6 mm, a depth L5 of 4 mm, 16 grooves, and a total cross-sectional area of ​​the spiral grooves as viewed in the axial direction of the cylindrical body 10 of 384 mm. 2 The rotation angle is 30° (please tell us the value), and in the fourth nozzle according to the test results of Figure 6, the width L6 of the spiral groove 10a is 3 mm, the depth L5 is 5 mm, the number of grooves is 16, and the total cross-sectional area of ​​the spiral grooves as viewed in the axial direction of the cylindrical body 10 is 240 mm 2 The turning angle was set to 30° (please let us know the value). The supply amount of heavy oil as atomized liquid fuel, which is the atomized mixed fuel supplied through the fuel flow path 30a, is 440 L / h, and the supply amount of city gas as gas fuel, which is the atomized mixed fuel, is 210 m 3 N / h. The amount of secondary combustion air supplied to the furnace from sources other than the gas atomizing burner 100 was 7000 m 3 N / h.

[0030] In the third combustion test, in each legend, the amount of combustion air supplied into the furnace through the primary straight combustion air flow path R3 was set to the same flow rate, the primary swirling combustion air flow path R2 was set to zero, and multiple combustion tests were conducted by adjusting the pressure loss in the primary swirling auxiliary combustion air flow path R1 and the head pressure at the tip of the cylindrical body 10. In the "target value" shown in the legend of FIG. 5, the opening degree of the control valve of the primary swirl auxiliary combustion air passage R1 is set to 50%, and in the "standard" shown in the legend of FIG. 5, the opening degree of the control valve is set to 20% to simulate the blockage of the primary swirl auxiliary combustion air passage R2, and combustion is performed using a cylindrical body 10 without spiral grooves 10a. In the "third nozzle (head pressure 32 kPaG)" shown in the legend of FIG. 5, the opening degree of the control valve is set to 20% to simulate the blockage of the primary swirl auxiliary combustion air passage R1, and the combustion air is supplied at a head pressure of 32 kPaG and a volume of 150 m 3 In the "Nozzle 3 (head pressure 58 kPaG)" shown in the legend of Figure 5, the control valve opening was set to 20% to simulate blockage of the primary swirl auxiliary combustion air flow path R1, and the combustion air was supplied at a head pressure of 58 kPaG and a rate of 200 m 3 / h.

[0031] On the other hand, in the "target value" shown in the legend of FIG. 6, the opening degree of the control valve of the primary swirl auxiliary combustion air passage R1 is set to 50%, and in the "standard" shown in the legend of FIG. 6, the opening degree of the control valve is set to 20% to simulate the blockage of the primary swirl auxiliary combustion air passage R2, and combustion is performed using a cylindrical body 10 without spiral grooves 10a. In the "fourth nozzle (head pressure 28 kPaG)" shown in the legend of FIG. 6, the opening degree of the control valve is set to 20% to simulate the blockage of the primary swirl auxiliary combustion air passage R1, and the combustion air is supplied at a head pressure of 28 kPaG and a flow rate of 100 m 3 In the "fourth nozzle (head pressure 62 kPaG)" shown in the legend of Figure 6, the control valve opening was set to 20% to simulate blockage of the primary swirl auxiliary combustion air passage R1, and the combustion air was supplied at a head pressure of 62 kPaG with a supply volume of 150 m 3 In the "fourth nozzle (head pressure 100 kPaG)" shown in the legend of Figure 6, the control valve opening is set to 20% to simulate blockage of the primary swirl auxiliary combustion air flow path R1, and the combustion air is supplied at a head pressure of 100 kPaG and a supply rate of 200 m 3 / h.

[0032] In this third combustion test, the aim is to raise the temperature of the third point (third plot), which is the third distance from the tip of the burner nozzle, above the "reference" temperature and approaching the "target value" of approximately 720°C. As can be seen from the test results in Figures 5 and 6, in the third plot, the temperature exceeds the "reference" temperature for both the third and fourth nozzles, and it is recognized that there is a temperature-raising effect even when the pressure loss in the primary swirl auxiliary combustion air flow path R1 is high. In particular, the temperature of the third plot is 3 / h, and when comparing the "3rd nozzle (head pressure 32 kPaG)" and the "4th nozzle (head pressure 62 kPaG)" which have the same flow rate, and when the flow rate is 200 m 3 When comparing the "third nozzle (head pressure 58 kPaG)" and the "fourth nozzle (head pressure 100 kPaG)" which have the same flow rate / h, it can be seen that a higher head pressure results in a greater temperature rise effect, and therefore it is preferable to use head pressure rather than flow rate as the control indicator.

[0033] [Another embodiment] (1) In the above embodiment, the primary swirl-assisted combustion air passage R1 is configured such that primary combustion air flows as an oxidant-containing gas containing an oxidant. As another example of the oxidant-containing gas containing an oxidant, a gas mixture containing a gas fuel such as city gas 13A may be used.

[0034] (2) In the above embodiment, the cylindrical body 10 may have either a configuration including the distal end expanded diameter portion 10b or a configuration not including the distal end expanded diameter portion 10b.

[0035] (3) In the above embodiment, a configuration may be adopted in which multiple swirl vanes 11 are not provided, or the swirling direction of the primary combustion air caused by the multiple swirl vanes 11 may be the same as the swirling direction of the primary combustion air caused by the multiple spiral grooves 10a of the cylindrical body 10.

[0036] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0037] The gas atomizing burner of the present invention can be effectively used as a gas atomizing burner that can effectively suppress the intrusion of dust from the object to be heated and the non-atomized liquid fuel from the atomized liquid fuel into the oxidizer-containing gas flow path, thereby suppressing a decrease in the flow rate of the oxidizer-containing gas supplied while preventing the flame from becoming long. [Explanation of symbols]

[0038] 10: Cylindrical body 10a: Spiral groove 10b: Expanded diameter part on the tip side 10c: Proximal part 11: Swivel wings 30:Fuel flow cylinder part 30a: Fuel flow path 31: First combustion air cylinder 100: Gas atomizing burner F:Flame P: Axial center R1: Primary swirl auxiliary combustion air passage

Claims

1. A gas atomizing burner comprising: a fuel flow tube portion serving as a fuel flow path through which atomized mixed fuel, which is a mixture of atomized liquid fuel atomized by atomizing liquid fuel and gas fuel, flows; and a nozzle portion at a tip of the fuel flow path for injecting the atomized mixed fuel flowing through the fuel flow path, an outer surrounding cylindrical portion that surrounds the fuel flow cylindrical portion and serves as an oxidant-containing gas flow path for flowing an oxidant-containing gas between the outer surrounding cylindrical portion and the fuel flow cylindrical portion; a cylindrical body that can be fitted into the oxidant-containing gas flow passage, the cylindrical body having a plurality of spiral grooves that swirl the oxidant-containing gas along an outer circumferential portion of the cylindrical body and guide it to a tip end, and a tip end side expanded diameter portion that is expanded in diameter in the axial direction relative to the outer diameter of a base end side portion of the cylindrical body; a compressor that pressure-feeds either combustion air or a mixture of the combustion air and the gas fuel as the oxidant-containing gas into the oxidant-containing gas passage; The gas atomizing burner has a plurality of spiral grooves formed continuously from the base end portion to the tip end expanded diameter portion.

2. a plurality of swirl vanes for swirling the oxidant-containing gas flowing through the oxidant-containing gas passage, the swirl vanes being provided on a base end side of the cylindrical body in the axial direction of the oxidant-containing gas passage; 2. The gas atomizing burner according to claim 1, wherein the swirling direction of the oxidant-containing gas caused by the plurality of spiral grooves in the cylindrical body is opposite to the swirling direction of the oxidant-containing gas caused by the plurality of swirling blades.

3. A gas atomizing burner comprising: a fuel flow tube portion serving as a fuel flow path through which atomized mixed fuel, which is a mixture of atomized liquid fuel atomized by atomizing liquid fuel and gas fuel, flows; and a nozzle portion at a tip of the fuel flow path for injecting the atomized mixed fuel flowing through the fuel flow path, an outer surrounding cylindrical portion that surrounds the fuel flow cylindrical portion and serves as an oxidant-containing gas flow path for flowing an oxidant-containing gas between the outer surrounding cylindrical portion and the fuel flow cylindrical portion; a cylindrical body that can be fitted into the oxidant-containing gas flow passage, the cylindrical body having a plurality of spiral grooves that swirl the oxidant-containing gas along the outer periphery of the cylindrical body and guide the gas to the tip; a compressor that pressure-feeds either combustion air or a mixture of the combustion air and the gas fuel as the oxidant-containing gas into the oxidant-containing gas passage; a plurality of swirl vanes for swirling the oxidant-containing gas flowing through the oxidant-containing gas flow path are provided on a base end side of the tubular body in the axial direction of the tubular body in the oxidant-containing gas flow path, A gas atomizing burner in which the swirling direction of the oxidant-containing gas caused by the plurality of spiral grooves in the cylindrical body is opposite to the swirling direction of the oxidant-containing gas caused by the plurality of swirling blades.

4. When viewed in the direction of the cylindrical axis of the cylindrical body, A gas atomizing burner as described in any one of claims 1 to 3, wherein the rotation angle of the multiple spiral grooves from the base end to the tip end of the cylindrical body is set in the range of 20° or more and 60° or less.

5. 5. The gas atomizing burner according to claim 1, wherein the compressor controls the pressure of the oxidizer-containing gas flowing out from the plurality of spiral grooves to be 60 kPaG or more and 150 kPaG or less.

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