Hydrogen gas combustion device and method for operating the hydrogen gas combustion device

Abstract

A hydrogen gas combustion device is provided that can prevent backfire and can stably form low-power hydrogen flames in a plurality of flame holes. [Solution] A hydrogen gas combustion device comprising: a nozzle having a plurality of flame holes formed therein and spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying inert gas to the nozzle; and a second inert gas line connected to the nozzle and capable of supplying inert gas to the nozzle at a smaller flow rate than the inert gas supplied from the first inert gas line.

Description

[Technical Field]

[0001] The present disclosure relates to a hydrogen gas combustion apparatus and a method of operating a hydrogen gas combustion apparatus. [Background technology]

[0002] Combustion devices that use hydrogen gas as fuel are well known. For example, Patent Document 1 discloses a grilling device that includes a burner that uses hydrogen gas as fuel gas, a moisture release section disposed below the burner, and a flow guide plate that directs moisture released from the moisture release section toward the flame ejected from the burner's flame hole. The grilling device in Patent Document 1 focuses on the fact that hydrogen gas has a fast combustion speed and is less likely to cause poor combustion, and utilizes this high combustion stability even when moisture comes into contact with the flame produced by burning hydrogen to cook food containing moisture.

[0003] Patent Document 2 discloses a fuel control device for a burner that can prevent flashbacks without using a flame arrester in a combustion device that uses hydrogen gas as fuel. The fuel control device of Patent Document 2 includes a supply line that selectively supplies fuel (hydrogen gas) or inert gas (nitrogen gas), and a first valve device and a second valve device disposed in the supply line. The first valve device is a three-way valve, and by switching this three-way valve, either fuel or inert gas is supplied to the burner. The second valve device switches the supply line between open and closed. Patent Document 2 discloses that flashbacks can be prevented by controlling the operation of the first valve device and the second valve device in a predetermined order. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-158434 [Patent Document 2] Patent No. 7515230 Summary of the Invention [Problem to be solved by the invention]

[0005] Hydrogen gas has a fast combustion speed, and when a burner using hydrogen gas as fuel is operated at low output (low flame), the hydrogen gas flow rate and combustion rate become counterbalanced as the hydrogen gas flow rate decreases, increasing the possibility of flashback. Furthermore, a decrease in the hydrogen gas flow rate makes it difficult for the hydrogen gas to reach the tip of the burner, which has a long nozzle, making it difficult to form a uniform flame throughout the burner. On the other hand, as the range of applications for hydrogen gas combustion devices expands, there is a demand for hydrogen gas burners that can form a uniform flame even at low output.

[0006] In view of this situation, one object of the present invention is to provide a hydrogen gas combustion apparatus that can prevent flashback and can stably form hydrogen flames in multiple flame holes even at low power output. Another object of the present invention is to provide a method of operating a hydrogen gas combustion apparatus that can prevent flashback and can stably form hydrogen flames in multiple flame holes even at low power output. [Means for solving the problem]

[0007] The hydrogen gas combustion device according to the present disclosure comprises: a nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; and a second inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line.

[0008] The method for operating a hydrogen gas combustion apparatus according to the present disclosure includes: a nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; The present invention is carried out in a hydrogen gas combustion device including a second inert gas line connected to the nozzle and capable of supplying inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line. The operating method includes: supplying an inert gas to the nozzle through the first inert gas line; a first combustion step of supplying hydrogen gas to the nozzle through the fuel gas line to form a hydrogen combustion flame in the flame hole; a second combustion step in which hydrogen gas is supplied to the nozzle through the fuel gas line while an inert gas is supplied through the second inert gas line, and a hydrogen combustion flame is formed in the flame hole with a lower output than the hydrogen combustion flame in the first combustion step; Includes. [Effects of the Invention]

[0009] The hydrogen gas combustion apparatus according to the present disclosure prevents flashback and allows stable formation of hydrogen flames in multiple flame holes even at low power output. The method of operating the hydrogen gas combustion apparatus according to the present disclosure is a method of operating the hydrogen gas combustion apparatus, which prevents flashback and allows stable formation of hydrogen flames in multiple flame holes even at low power output. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a combustion device according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of a combustion device according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is an explanatory diagram showing the configuration of a combustion device according to one embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram showing one embodiment of a nozzle of a combustion device according to one embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic diagram showing one embodiment of a nozzle of a combustion device according to one embodiment of the present disclosure. [Figure 6] FIG. 6 is a flowchart of a method for operating a combustion apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Outline of the embodiment] First, embodiments of the combustion apparatus and the operating method thereof according to the present disclosure will be listed and described. The hydrogen gas combustion device according to the present disclosure comprises: a nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; and a second inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line.

[0012] Because hydrogen does not emit CO2 when burned, it can be used as an alternative to fossil fuels, thereby reducing CO2 emissions. In response to societal demands for reducing CO2 emissions, technological development is underway for combustion equipment that uses hydrogen gas as fuel.

[0013] Generally, when adjusting the output of a gas burner, the flame power is adjusted by controlling the fuel flow rate, but at this time, the flow velocity changes along with the change in fuel flow rate. Because hydrogen gas has a faster combustion rate than fossil fuels, a slower fuel flow rate increases the likelihood of backfire, making it difficult to operate at low output. Furthermore, because the flow rate is lower at low output, it has become clear that insufficient fuel gas is supplied to the tip of the nozzle, resulting in uneven combustion in the burner.

[0014] The hydrogen gas combustion device according to the present disclosure has a line that supplies hydrogen gas as fuel to a nozzle and two inert gas lines with different supply flow rates. The hydrogen gas combustion device can supply a mixture of inert gas and hydrogen gas supplied from the low-flow inert gas line to the nozzle. Therefore, even when the flow rate of hydrogen gas is low, the flow rate of the mixture gas that serves as fuel can be maintained. This configuration allows a stable flame to be formed across the entire nozzle even at low output, and prevents flashback.

[0015] In the hydrogen gas combustion device, a first pressure reducing valve is provided in the first inert gas line, The second inert gas line may be provided with a second pressure reducing valve, and the first and second pressure reducing valves may be provided in parallel with each other. With this configuration, the inert gas supplied through the first inert gas line (inert gas for purging the piping) and the inert gas supplied through the second inert gas line (gas to be mixed with hydrogen gas to adjust the fuel flow rate) can be controlled independently.

[0016] In the hydrogen gas combustion apparatus, the first inert gas line may be provided with a first pressure reducing valve, and the second inert gas line may be provided with a second pressure reducing valve, the second pressure reducing valve being provided downstream of the first pressure reducing valve. With this configuration, the pressure and flow rate of the inert gas supplied to the burner can be reduced stepwise by the first and second pressure reducing valves, facilitating fine flow rate adjustment and easier control of a small, low-power flame.

[0017] The combustion device according to the present disclosure comprises the hydrogen gas combustion device and a gas burner equipped with a hydrocarbon gas nozzle arranged in parallel to the nozzle. By providing both the hydrocarbon gas burner and the hydrogen burner, a combustion device is provided that can adjust the heat output over a wide range and has a low environmental impact, by utilizing the stable and powerful flame of the hydrocarbon gas burner and the clean flame of the hydrogen gas burner in combination.

[0018] A method for operating a hydrogen gas combustion apparatus according to the present disclosure is a method carried out in the aforementioned hydrogen gas combustion apparatus, and includes the steps of: supplying an inert gas to the nozzle through the first inert gas line, supplying hydrogen gas to the nozzle through the fuel gas line to form a hydrogen combustion flame in a flame hole of the nozzle (a first combustion step), and supplying an inert gas to the nozzle through the second inert gas line while supplying hydrogen gas through the fuel gas line to form a hydrogen combustion flame in a flame hole of the nozzle that is smaller than the hydrogen combustion flame in the first combustion step.

[0019] The operating method includes a piping purging step of supplying inert gas through the first inert gas line, a step of burning only hydrogen gas (high-power combustion), and a step of supplying a mixture of hydrogen gas and inert gas to form a small hydrogen combustion flame (low-power combustion). The operating method including these steps can stably form both high-power and low-power hydrogen flames across the entire nozzle. Furthermore, backfire is prevented even at low power. This operating method allows for stable heating across a wide range of applications of the hydrogen gas combustion device.

[0020] [Specific example of embodiment] Next, specific embodiments of a hydrogen gas combustion apparatus and a combustion apparatus including a hydrogen gas combustion apparatus according to the present disclosure will be described with reference to the drawings. In the following drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. In this specification, in a hydrogen gas combustion apparatus, the side closer to the gas supply source is referred to as the "upstream side," and the side closer to the nozzle tip is referred to as the "downstream side." However, in operation of the combustion apparatus, the flow direction of gas through each part of the apparatus is not limited to this, and gas may flow in the opposite direction due to purging, cleaning, or other operations.

[0021] (Hydrogen gas combustion device) (Embodiment 1) Fig. 1 is an explanatory diagram showing the configuration of a hydrogen gas combustion apparatus according to one embodiment of the present disclosure. Referring to Fig. 1, the hydrogen gas combustion apparatus 1 includes a burner 10 and a gas supply device 30. Gas supplied from a supply source (not shown) is supplied to the burner 10 via the gas supply device 30.

[0022] The burner 10 includes a nozzle 20. The nozzle 20 is a long, straight tube, and a supply pipe 45 is connected to one end of the nozzle 20. The end of the nozzle 20 opposite to the end connected to the supply pipe 45 is closed. A plurality of flame holes 21 are formed along the longitudinal direction of the nozzle 20, spaced apart from one another. The burner 10 may include an ignition device, etc., not shown.

[0023] The gas supply device 30 includes a hydrogen gas line 41, a first inert gas line 42, a second inert gas line 43, and an air supply line 44. The hydrogen gas line 41, the first inert gas line 42, and the second inert gas line 43 are connected to the nozzle 20 via supply piping 45. The air supply line 44 is also connected to the burner 10.

[0024] The hydrogen gas line 41 is a line for supplying hydrogen gas (H2) as fuel. The hydrogen gas line 41 is made of a metal pipe such as a stainless steel pipe. The hydrogen gas may be supplied from a gas storage facility such as a cylinder, tank, or curdle, and the supply source is not particularly limited. Along the hydrogen gas line 41, in order from the upstream side, there are provided a pressure reducing valve PV2, a flow meter FM2, a flow rate adjustment valve FV2, an on-off valve V2, and a check valve CV2.

[0025] The first inert gas line 42 is a line for supplying an inert gas to the nozzle 20. The inert gas may be, for example, nitrogen gas, but is not limited to nitrogen gas. For example, helium gas, argon gas, etc. may also be used. In consideration of versatility, nitrogen gas is preferable. The specific configuration of the first inert gas line 42 is not limited as long as it has the predetermined function, but it is made of a metal pipe such as a stainless steel pipe. The first inert gas line 42 is connected to the hydrogen gas line 41 downstream of the check valve CV2, and is connected to the nozzle 20 via the hydrogen gas line 41 and supply piping 45. When purging the hydrogen gas line 41 and the burner 10, inert gas is supplied from the first inert gas line 42 at a flow rate and pressure suitable for purging.

[0026] Along the first inert gas line 42, there are provided, in order from the upstream side, a pressure reducing valve PV3 as a first pressure reducing valve, a flow meter FM3, a flow rate adjustment valve FV3, an on-off valve V3, and a check valve CV3. These valves adjust the opening and closing of the first inert gas line 42 and the flow rate of the inert gas.

[0027] The second inert gas line 43 is a line for supplying an inert gas to the nozzle 20. The inert gas flowing through the second inert gas line 43 may be the same type of gas as the inert gas in the first inert gas line 42, for example, nitrogen gas. The inert gas may be supplied to both the first inert gas line 42 and the second inert gas line 43 from a single gas supply source (for example, a nitrogen gas cylinder). The second inert gas line 43 is made of a metal pipe such as a stainless steel pipe. The second inert gas line 43 is connected to the hydrogen gas line 41 midway along the hydrogen gas line 41, downstream of the connection point with the first inert gas line 42. The second inert gas line 43 is connected to the nozzle 20 via the hydrogen gas line 41 and a supply pipe 45.

[0028] Along the second inert gas line 43, there are provided, in order from the upstream side, a pressure reducing valve PV4 as a second pressure reducing valve, a flow meter FM4, a flow rate adjustment valve FV4, an on-off valve V4, and a check valve CV4. These valves adjust the opening and closing of the second inert gas line 43 and the flow rate of the inert gas. The amount of inert gas supplied through the second inert gas line 43 is smaller than the amount of inert gas supplied from the first inert gas line 42.

[0029] The second inert gas line 43 can supply the inert gas to the nozzle 20 at a flow rate lower than the inert gas supplied from the first inert gas line 42. By supplying hydrogen gas through the hydrogen gas line 41 while simultaneously supplying inert gas through the second inert gas line 43, a mixed gas of hydrogen gas and inert gas can be sent to the nozzle 20.

[0030] By using a mixture of hydrogen gas and an inert gas as the fuel gas, the flow rate of the entire mixture can be maintained even when the hydrogen gas flow rate is low. This allows a small amount of hydrogen gas to be supplied to the nozzle while maintaining a sufficient flow rate. This not only suppresses flashbacks, but also allows the gas to reach the tip of the nozzle, forming a uniform flame throughout the nozzle.

[0031] In the hydrogen gas combustion device 1, the first inert gas line 42 and the second inert gas line 43 are arranged as independent lines with no shared areas. The pressure reducing valve PV3 (first pressure reducing valve) and the pressure reducing valve PV4 (second pressure reducing valve) are provided in parallel with each other. With this configuration, purging of the nozzles and piping can be performed using the first inert gas line as in the conventional case, and when attempting to form a low-power flame, a small amount of inert gas can be supplied via the second inert gas line 43 as necessary.

[0032] The air supply line 44 is a line for supplying air (secondary air) to the fuel gas (hydrogen gas or mixed gas) in the burner 10. Along the air supply line 44, in this order from the upstream side, there are provided a pressure reducing valve PV5, a flow meter FM5, a flow rate adjusting valve FV5, and an on-off valve V5. The air supplied from the air supply line promotes the combustion of the fuel.

[0033] (Embodiment 2) Fig. 2 is an explanatory diagram showing the configuration of a combustion device according to one embodiment of the present disclosure. Referring to Fig. 2, the combustion device 100 includes a burner 110 and a gas supply device 130. Gas supplied from a supply source (not shown) is supplied to the burner 110 via the gas supply device 130. The combustion device 100 is a combustion device that combines a hydrogen gas burner and a hydrocarbon gas (e.g., propane gas) burner. The combustion device 100 is a device (e.g., a hydrogen-mixed combustion burner) that includes a gas burner that can stably generate an inexpensive hydrocarbon flame with a large amount of heat, and a hydrogen burner that can generate a clean, uniform, low-output flame.

[0034] The burner 110 includes a nozzle 120 that is a hydrogen gas combustion section, and a hydrocarbon gas burner nozzle 150. The hydrocarbon gas burner may be an existing gas burner that uses propane gas or the like as fuel. The nozzle 150 is elongated, and the nozzle 120 and the nozzle 150 are arranged side by side.

[0035] The nozzle 120 and the gas supply device 130 connected to the nozzle 120 are similar to the nozzle 20 and the gas supply device 30 in the hydrogen gas combustion device 1, and therefore a description thereof will be omitted.

[0036] The gas supply device 130 includes a hydrocarbon gas supply line 145 connected to a nozzle 150 of the burner 110. The hydrocarbon gas supply line 145 is a line that supplies hydrocarbon gas supplied from a gas supply source (e.g., a propane gas cylinder, a propane gas line, etc.) to the nozzle 150. Along the hydrocarbon gas supply line 145, a pressure reducing valve PV1, a flow meter FM1, a flow rate adjustment valve FV1, and an on-off valve V1 are provided in this order from the upstream side.

[0037] (Embodiment 3) Fig. 3 is an explanatory diagram showing the configuration of a combustion apparatus according to one embodiment of the present disclosure. Referring to Fig. 3, the combustion apparatus 200 includes a burner 110 and a gas supply device 230. Various gases are supplied to the burner 110 via the gas supply device 230. Like the combustion apparatus 100, the combustion apparatus 200 is a combustion apparatus that combines a hydrogen gas burner and a hydrocarbon gas burner. The burner 110 has the same configuration as that in the combustion apparatus 100, and therefore a description thereof will be omitted. The gas supply device 230 differs from the gas supply device 30 in that a second inert gas line 243 is provided branching off from the first inert gas line 242.

[0038] The gas supply device 230 includes a hydrogen gas line 241, a first inert gas line 242, a second inert gas line 243, an air supply line 44, and a hydrocarbon gas supply line 145. The configurations of the air supply line 44 and the hydrocarbon gas supply line 145 are as described above, and therefore a description thereof will be omitted. The hydrogen gas line 241, the first inert gas line 242, and the second inert gas line 243 are connected to the nozzle 120 via the supply piping 245.

[0039] The hydrogen gas line 241 is a line for supplying hydrogen gas (H2) as fuel. The specific configuration of the hydrogen gas line 241 is not particularly limited as long as it has a predetermined function, but it may be made of a metal pipe such as a stainless steel pipe. Along the hydrogen gas line 241, in this order from the upstream side, there are provided a pressure reducing valve PV2, a flow meter FM2, a flow rate adjusting valve FV2, and an on-off valve V2. A check valve (not shown) may also be provided to regulate the flow direction of the gas.

[0040] The first inert gas line 242 is a line for supplying an inert gas, such as nitrogen gas, to the nozzle 120. The first inert gas line 242 may be made of a metal pipe such as a stainless steel pipe. The first inert gas line 242 is connected to the middle of the hydrogen gas line 241, and is connected to the nozzle 120 via the hydrogen gas line 241 and a supply pipe 245. When purging the hydrogen gas line 241 and the burner 110, an inert gas is supplied from the first inert gas line 242 at a flow rate and pressure suitable for purging.

[0041] Along the first inert gas line 242, a pressure reducing valve PV3 serving as a first pressure reducing valve, a flow meter FM3, a flow rate adjustment valve FV3, and an on-off valve V3 are provided in this order from the upstream side. A check valve (not shown) may be provided to regulate the flow direction of the gas. A second inert gas line 243 is connected to the first inert gas line 242 upstream of the inert gas on-off valve V3. The other end of the second inert gas line 243 is connected to the hydrogen gas line 241 downstream of the connection position of the hydrogen gas line 241 to the first inert gas line 242.

[0042] Along the second inert gas line 243, a pressure reducing valve PV4' serving as a second pressure reducing valve, a flow meter FM4', a flow rate adjustment valve FV4', and an on-off valve V4' are provided in this order from the upstream side. That is, the pressure reducing valve PV4' (second pressure reducing valve) is provided downstream of the pressure reducing valve PV3 (first pressure reducing valve) in series. These valves adjust the opening and closing of the second inert gas line 243 and the flow rate of the inert gas. The inert gas supplied through the second inert gas line 243 is the inert gas supplied from the first inert gas line 242, whose pressure has been reduced and whose flow rate has been adjusted by the pressure reducing valve PV4' and the flow rate adjustment valve FV4'.

[0043] When purging the piping of the combustion device 200, inert gas is supplied at a pressure and flow rate suitable for purging through the first inert gas line 242. On the other hand, when forming a hydrogen flame in the nozzle 120, hydrogen gas is supplied through the hydrogen gas line 241, but during low-power combustion, inert gas is simultaneously supplied at an adjusted flow rate through the second inert gas line 243, thereby forming a mixed gas of hydrogen gas and inert gas and sending the mixed gas to the nozzle 120.

[0044] (nozzle) FIG. 4 is a schematic diagram showing one embodiment of a nozzle of a hydrogen gas combustion apparatus according to the present disclosure. The nozzle 20 has a long, cylindrical main body 22, and multiple flame holes 21 are formed in the main body 22 at intervals. A connector 27 is provided at the end of the nozzle 20, and a supply pipe 45 is connected to the nozzle. In the example shown in FIG. 4, the nozzle 20 is a straight cylindrical tube, but this shape is not limited to this. For example, the cross section perpendicular to the axial direction of the nozzle may be a polygonal shape, such as a square, pentagon, or hexagon. The nozzle may also be longer, with multiple straight and curved tube sections alternately connected. Conventionally, it has been difficult to pass a small amount of hydrogen gas through a long tube nozzle. In this regard, the combustion apparatus of the present invention supplies a mixed gas of hydrogen gas and an inert gas to the nozzle, allowing the hydrogen gas to reach the end of the nozzle even when the flow rate is low.

[0045] FIG. 5 is a schematic diagram showing one form of a nozzle of a hydrogen gas combustion apparatus according to an embodiment of the present disclosure. The nozzle 20 has a hollow, annular main body 22, which has a plurality of flame holes 21 formed at a distance from one another. The end of the nozzle 20 is equipped with a connector 27, to which a supply pipe can be connected. Conventionally, when a small amount of hydrogen gas is passed through a small-diameter, long nozzle, the flow rate and pressure are insufficient, making it difficult for the hydrogen gas to reach the end of the nozzle and produce a uniform flame. However, with the hydrogen gas combustion apparatus according to the present disclosure, when the amount of hydrogen gas is small, an inert gas can be mixed in to maintain the flow rate of the gas. This allows for a high degree of freedom in the shape and length of the nozzle in the hydrogen gas combustion apparatus.

[0046] In the hydrogen gas combustion device according to the present disclosure, the specific dimensions of the nozzle are not particularly limited as long as the effects of the invention can be obtained. For example, the area of ​​the cross section perpendicular to the axial direction of the nozzle is 300 to 5,000 mm 2 The nozzle diameter may be about d (mm), and the axial (longitudinal) length may be about 100 to 8,000 mm. When the cross-sectional diameter of the nozzle (the length of the diagonal in the cross section when the cross section is square) is d (mm), and the axial (longitudinal) length is l (mm), the ratio l / d may be in the range of 5 to 100, and is more preferably 20 to 100.

[0047] (How to drive) The operating method according to the present disclosure includes the steps of supplying an inert gas to a nozzle and piping through which hydrogen flows and purging the nozzle with the inert gas, a first combustion step of supplying hydrogen gas to the nozzle to form a hydrogen combustion flame, and a second combustion step of supplying a mixed gas of hydrogen gas and an inert gas to the nozzle to form a hydrogen combustion flame (a low-output flame) smaller than the hydrogen combustion flame in the first combustion step. The apparatus for carrying out the operating method according to the present disclosure is not limited as long as it is capable of carrying out the specified steps, but is preferably carried out in the combustion apparatus described above. The location where the combustion apparatus is used is not particularly limited, but it is used as a heating device in, for example, commercial cooking equipment, food manufacturing equipment such as tunnel ovens, and baking equipment such as rotary kilns and rotary furnaces.

[0048] An operating method will be described below with reference to the combustion apparatus 100 shown in Fig. 2 and the flow shown in Fig. 6. In the combustion apparatus 100, the upstream side of the hydrocarbon gas pressure reducing valve PV1 is connected to an LPG storage facility (LPG cylinder, LPG tank, etc.). The upstream side of the hydrogen pressure reducing valve PV2 is connected to a hydrogen gas storage container (e.g., a hydrogen gas cylinder). The upstream sides of the first inert gas pressure reducing valve PV3 and the second inert gas pressure reducing valve PV4 are connected to a nitrogen gas storage container (e.g., a nitrogen gas cylinder). The upstream side of the air pressure reducing valve PV5 may be connected to a compressor or pump that supplies compressed air.

[0049] (1) Preparation step (pressure adjustment and flow rate adjustment) In the combustion device 100, the hydrocarbon gas pressure reducing valve PV1, the hydrogen pressure reducing valve PV2, the first inert gas pressure reducing valve PV3, the second inert gas pressure reducing valve PV4, and the air pressure reducing valve PV5 are each adjusted to a predetermined pressure. Also, the hydrocarbon gas flow rate control valve FV1, the hydrogen flow rate control valve FV2, the inert gas flow rate control valve FV3, the inert gas flow rate control valve FV4, and the air flow rate control valve FV5 are each adjusted to a predetermined flow rate so that gas flows at a flow rate required for combustion.

[0050] (2) Pilot ignition The hydrocarbon gas on-off valve V1 is opened, and hydrocarbon gas is supplied to and ignited in the nozzle 150. After it is confirmed that the hydrocarbon gas flame in the nozzle 150 has stabilized, the hydrocarbon gas flow control valve FV1 is adjusted to adjust the flow rate to a predetermined level.

[0051] (3) Purging the hydrogen piping After adjusting the hydrocarbon gas to a predetermined flow rate in the nozzle 150, the hydrogen piping is purged (S10 in FIG. 6). The purging is performed by opening the inert gas on-off valve V3 and maintaining the predetermined flow rate for a predetermined time. The inert gas is supplied to the hydrogen gas line 41, the nozzle 120, and the second inert gas line 43 through the first inert gas line 42. Because the hydrogen gas line 41 is equipped with a check valve CV2, the piping downstream of the check valve CV2 is purged. After a predetermined time has elapsed, the inert gas on-off valve V3 is closed to end the purging.

[0052] (4) Hydrogen ignition Next, the hydrogen on-off valve V2 is opened, and hydrogen gas is supplied to the nozzle 120 through the hydrogen gas line 41 and ignited. Note that the first inert gas line 42 is provided with a check valve CV3, so that the hydrogen gas does not flow back upstream of the check valve CV3 (toward the inert gas supply source).

[0053] (5) Increased output (high-power combustion) The combustion output is increased so that the object to be heated or the atmosphere reaches a predetermined temperature (S20 in FIG. 6). The openings of the hydrocarbon gas flow control valve FV1, hydrogen flow control valve FV2, and air flow control valve FV5 are adjusted to increase the flow rates of fuel and air.

[0054] (6) Maintaining the target temperature (low-power combustion) After it is confirmed that the specified temperature has been reached, the combustion output is adjusted to a lower level in order to maintain the target temperature. The openings of the hydrocarbon gas flow control valve FV1, hydrogen flow control valve FV2, and air flow control valve FV5 are adjusted to reduce the flow rates of fuel and air.

[0055] At this time, if the hydrogen gas falls below a specified flow rate, the mixed gas of hydrogen gas and inert gas is combusted (S30 in FIG. 6). That is, the inert gas on-off valve V4 is opened and inert gas is supplied through the second inert gas line 43. The inert gas and hydrogen gas are mixed in the flow path, and the mixed gas is supplied to the nozzle 120. The mixed gas maintains the gas flow rate and prevents flashback. Furthermore, because the mixed gas reaches the tip of the nozzle 120, a uniform hydrogen flame is formed throughout the entire nozzle 120. If it is desired to further reduce the output, the openings of the hydrogen flow control valve FV2 and the air flow control valve FV5 are narrowed, and the inert gas flow control valve FV4 is adjusted to maintain the mixed gas flow rate above the combustion speed.

[0056] The order in which the high-power combustion step and the low-power combustion step are performed is not necessarily limited to the above order. For example, high-power combustion may be performed again after high-power combustion and low-power combustion have been performed, or high-power combustion and low-power combustion may be switched between as needed depending on the purpose of heating.

[0057] The embodiments disclosed herein are illustrative in all respects and should not be construed as limiting. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0058] 1 hydrogen gas combustion device, 10, 110 burner, 20, 120, 150 nozzle, 21 flame hole, 22 main body, 27 connector, 30, 130, 230 gas supply device, 41, 241 hydrogen gas line, 42, 242 first inert gas line, 43, 243 second inert gas line, 44 air supply line, 145 hydrocarbon gas supply line, 45, 245 supply piping, 100, 200 combustion device, CV1, CV2, CV3, CV4, CV5 check valve, FM1, FM2, FM3, FM4, FM4', FM5 flow meter, FV1, FV2, FV3, FV4, FV4', FV5 flow control valve, PV1, PV2, PV3, PV4, PV4' pressure reducing valve, V1, V2, V3, V4, V4'V5 on-off valve.

Claims

1. a nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; a second inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line; the first inert gas line is a supply line for a purge gas, the second inert gas line is an inert gas supply line for mixing with the hydrogen gas supplied from the hydrogen gas line to form a fuel mixture gas; Hydrogen gas combustion device.

2. a first pressure reducing valve is provided in the first inert gas line; the second inert gas line is provided with a second pressure reducing valve; The first pressure reducing valve and the second pressure reducing valve are provided in parallel with each other. The hydrogen gas combustion device according to claim 1 .

3. A nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; a second inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line; a first pressure reducing valve is provided in the first inert gas line; the second inert gas line is provided with a second pressure reducing valve; The second pressure reducing valve is provided downstream of the first pressure reducing valve. Hydrogen gas combustion device.

4. A nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; a second inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line; and a hydrocarbon gas burner having a nozzle arranged in parallel with the nozzle; Combustion device.

5. a nozzle having a plurality of flame holes spaced apart from one another; a hydrogen gas line connected to the nozzle and capable of supplying hydrogen gas to the nozzle; a first inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle; a second inert gas line connected to the nozzle and capable of supplying an inert gas to the nozzle at a flow rate smaller than that of the inert gas supplied from the first inert gas line; A hydrogen gas combustion device comprising: supplying an inert gas to the nozzle through the first inert gas line; a first combustion step of supplying hydrogen gas to the nozzle through the hydrogen gas line to form a hydrogen combustion flame in the flame hole; a second combustion step in which hydrogen gas is supplied to the nozzle through the hydrogen gas line while inert gas is supplied through the second inert gas line, and a hydrogen combustion flame smaller than the hydrogen combustion flame in the first combustion step is formed in the flame hole; A method for operating a hydrogen gas combustion device, comprising:

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