Combustion system and combustion method

Abstract

To prevent backfire at low cost.SOLUTION: A combustion system 100 includes: a main burner 210; a main fuel supply part 220 that supplies either one or both of fuel gas at least including hydrogen or acetylene and hydrocarbon to the main burner 210 as main fuel; and a control section that controls the main fuel supply part 220. The control section performs in-operation control for operating the main fuel supply part 220 and supplying fuel gas to the main burner as main fuel, and after the in-operation control, performs extinction control for operating the main fuel supply part 220 to supply hydrocarbon to the main burner 210 as main fuel.SELECTED DRAWING: Figure 3

Description

Technical Field

[0008] , ,

[0001] The present invention relates to combustion systems such as industrial heating furnaces, boilers, hot water heaters, and combustion methods.

Background Art

[0011] Furthermore, the system includes a pilot burner with a smaller diameter than the main burner, and a pilot fuel supply unit that supplies either fuel gas or hydrocarbons, or both, to the pilot burner as pilot fuel. The control unit may, in ignition control, operate the pilot fuel supply unit to start supplying pilot fuel to the pilot burner, and after starting to supply pilot fuel to the pilot burner, operate the main fuel supply unit to start supplying hydrocarbons to the main burner.

[0012] Furthermore, the pilot fuel supply unit may supply fuel gas to the pilot burner as pilot fuel, and the control unit may operate the pilot fuel supply unit throughout the ignition control, operation control, and fire extinguishing control processes to continue supplying pilot fuel to the pilot burner.

[0013] Furthermore, the control unit may stop the operation of the pilot fuel supply unit during operation control.

[0014] Also , regulation In fire suppression control, the unit may operate the pilot fuel supply unit to start supplying pilot fuel to the pilot burner, and after starting to supply pilot fuel to the pilot burner, open the first on-off valve and close the second on-off valve. To solve the above problems, another combustion system of the present invention comprises a main burner, a main fuel supply unit that supplies either or both of a fuel gas containing at least hydrogen or acetylene and a hydrocarbon to the main burner as the main fuel, a pilot burner having a smaller diameter than the main burner, a pilot fuel supply unit that supplies fuel gas to the pilot burner as pilot fuel, and a control unit that controls the main fuel supply unit and the pilot fuel supply unit, wherein the main fuel supply unit has a hydrocarbon supply path connecting a hydrocarbon supply source to the main burner and a fuel gas supply path connecting a fuel gas supply source to the hydrocarbon supply path, and the control unit controls the pilot fuel supply The control unit operates the fuel supply unit to start supplying pilot fuel to the pilot burner, and after starting to supply pilot fuel to the pilot burner, it operates the main fuel supply unit to start supplying hydrocarbons as the main fuel to the main burner as ignition control, after ignition control operates the main fuel supply unit to supply fuel gas as the main fuel to the main burner as operating control, after operating control operates the main fuel supply unit to supply hydrocarbons as the main fuel to the main burner as extinguishing control, and the control unit operates the pilot fuel supply unit to continue supplying pilot fuel to the pilot burner throughout the ignition control, operating control and extinguishing control. To solve the above problems, another combustion system of the present invention comprises a main burner, a main fuel supply unit that supplies either or both of a fuel gas containing at least hydrogen or acetylene and a hydrocarbon to the main burner as the main fuel, a pilot burner having a smaller diameter than the main burner, a pilot fuel supply unit that supplies either or both of the fuel gas and hydrocarbon to the pilot burner as pilot fuel, and a control unit that controls the main fuel supply unit and the pilot fuel supply unit, wherein the main fuel supply unit comprises a hydrocarbon supply passage connecting a hydrocarbon supply source to the main burner, a fuel gas supply passage connecting a fuel gas supply source to the hydrocarbon supply passage, a first on-off valve provided in the hydrocarbon supply passage, and a second on-off valve provided in the fuel gas supply passage. The control unit operates the pilot fuel supply unit to start supplying pilot fuel to the pilot burner, and after starting to supply pilot fuel to the pilot burner, operates the main fuel supply unit to start supplying hydrocarbons as the main fuel to the main burner as ignition control, and after the ignition control, operates the main fuel supply unit to start supplying fuel gas to the main burner as the main fuel as operation control, and after the operation control, operates the main fuel supply unit to start supplying hydrocarbons as the main fuel to the main burner as fire extinguishing control, and in the fire extinguishing control, the control unit operates the pilot fuel supply unit to start supplying pilot fuel to the pilot burner, and after starting to supply pilot fuel to the pilot burner, opens the first on-off valve and closes the second on-off valve.

[0015] To solve the above problems, the combustion method of the present invention is as follows: A combustion method using a combustion system comprising a main burner, a hydrocarbon supply line connecting a hydrocarbon supply source to the main burner, a fuel gas supply line connecting a fuel gas supply source containing at least hydrogen or acetylene to the hydrocarbon supply line, a first on-off valve provided in the hydrocarbon supply line, and a second on-off valve provided in the fuel gas supply line, wherein the combustion method involves ignition control to supply hydrocarbons to the main burner, and after the ignition control, During operation, control is performed to supply fuel gas to the main burner. thing After the operation control, extinguishing control is performed to supply hydrocarbons to the main burner. This includes the following, and in ignition control, when the internal temperature of the furnace in which the main burner is installed rises above a predetermined temperature, the second shut-off valve is opened and the first shut-off valve is closed. . To solve the above problems, another combustion method of the present invention is a combustion method using a combustion system comprising a main burner, a hydrocarbon supply line connecting a hydrocarbon supply source to the main burner, a fuel gas supply line connecting a fuel gas supply source containing at least hydrogen or acetylene to the hydrocarbon supply line, and a pilot burner having a smaller diameter than the main burner, the combustion method comprising: performing ignition control to start supplying pilot fuel to the pilot burner, and after starting the supply of pilot fuel to the pilot burner, performing in-operation control to supply fuel gas to the main burner after the ignition control, and performing extinguishing control to supply hydrocarbon to the main burner after the in-operation control, wherein fuel gas is supplied to the pilot burner as pilot fuel, and the supply of pilot fuel to the pilot burner is continued throughout the ignition control, in-operation control, and extinguishing control. To solve the above problems, another combustion method of the present invention is a combustion method using a combustion system comprising: a main burner; a hydrocarbon supply line connecting a hydrocarbon supply source to the main burner; a fuel gas supply line connecting a fuel gas supply source containing at least hydrogen or acetylene to the hydrocarbon supply line; a first on-off valve provided in the hydrocarbon supply line; a second on-off valve provided in the fuel gas supply line; and a pilot burner having a smaller diameter than the main burner, wherein the combustion method includes: performing ignition control to start supplying pilot fuel to the pilot burner, and after starting the supply of pilot fuel to the pilot burner, starting the supply of hydrocarbon to the main burner; performing in-operation control to supply fuel gas to the main burner after the ignition control; and performing extinguishing control to supply hydrocarbon to the main burner after the in-operation control, wherein in the extinguishing control, the supply of pilot fuel to the pilot burner is started, and after starting the supply of pilot fuel to the pilot burner, the first on-off valve is opened and the second on-off valve is closed, and the pilot fuel is either fuel gas or hydrocarbon, or both.

Advantages of the Invention

[0016] According to the present invention, it is possible to prevent flashback at low cost.

Brief Description of the Drawings

[0017] [Figure 1] It is a diagram for explaining a combustion system according to an embodiment. [Figure 2] It is a functional block diagram of a control device according to an embodiment. [Figure 3] It is a diagram for explaining a burner device according to an embodiment. [Figure 4] It is a diagram for explaining the control of a flow rate control unit according to an embodiment. [Figure 5] It is a flowchart showing the process flow of a combustion method according to an embodiment. [Figure 6] It is a diagram for explaining a burner device according to a first modification example. [Figure 7] It is a diagram for explaining the control of a flow rate control unit according to a first modification example. [Figure 8] It is a diagram for explaining the control of a flow rate control unit according to a second modification example. [Figure 9] It is a diagram for explaining the control of a flow rate control unit according to a third modification example.

Modes for Carrying Out the Invention

[0018] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0019] Figure 1 is a diagram illustrating the combustion system 100 according to this embodiment. In Figure 1, solid arrows indicate the flow of fuel gas, dashed arrows indicate the flow of hydrocarbons, and dashed arrows indicate the flow of signals. Note that in Figure 1, the dashed arrow indicating the signal flow from the control device 140 to the burner device 120 is omitted.

[0020] As shown in Figure 1, the combustion system 100 includes a combustion device 110, a burner device 120, a temperature sensor 130, and a control device 140.

[0021] The combustion equipment 110 is a furnace for burning fuel gas. The combustion equipment 110 is, for example, an industrial heating furnace, a furnace that makes up a boiler or chiller / heater, etc. The combustion equipment 110 comprises one or more burner devices 120.

[0022] A fuel gas supply source 150 is connected to the burner device 120. A main shut-off valve 152 is provided between the fuel gas supply source 150 and the burner device 120. The main shut-off valve 152 opens and closes the flow path formed between the fuel gas supply source 150 and the burner device 120.

[0023] The fuel gas is either or both a gas with a combustion rate faster than a hydrocarbon and a gas with a higher adiabatic flame temperature than a hydrocarbon. The fuel gas includes, for example, at least one or both of hydrogen and acetylene. The combustion rate of hydrogen is about seven times that of hydrocarbons (e.g., city gas 13A). The adiabatic flame temperature of hydrogen is about 200°C higher than that of methane or city gas 13A. In this embodiment, hydrogen is given as an example of the fuel gas.

[0024] Furthermore, a hydrocarbon supply source 160 is connected to the burner device 120. A main shut-off valve 162 is provided between the hydrocarbon supply source 160 and the burner device 120. The main shut-off valve 162 opens and closes the flow path formed between the hydrocarbon supply source 160 and the burner device 120.

[0025] The hydrocarbon includes, for example, one or more of methane, ethane, propane, and butane. The hydrocarbon is, for example, city gas 13A. The hydrocarbon is supplied to the burner device 120 in gaseous form.

[0026] The burner device 120 burns either or both of the fuel gas and hydrocarbons with an oxidizing gas. The oxidizing gas includes one or more of air, oxygen, and oxygen-enriched gases. In this embodiment, air is given as an example of the oxidizing gas.

[0027] The temperature sensor 130 detects the internal temperature of the combustion equipment 110 (the internal temperature of the furnace).

[0028] The control device 140 manages and controls the entire combustion system 100.

[0029] Figure 2 is a functional block diagram of the control device 140 according to this embodiment. As shown in Figure 2, the control device 140 includes a central control unit 142 and a memory 144.

[0030] The central control unit 142 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit). The central control unit 142 reads programs and parameters for operating the CPU from ROM. The central control unit 142 works in cooperation with RAM, which serves as a work area, and other electronic circuits to manage and control the entire combustion system 100.

[0031] In this embodiment, the central control unit 142 functions as a flow rate control unit 170. The flow rate control unit 170 (control unit) controls the burner device 120. Details of the flow rate control unit 170 will be described later.

[0032] Memory 144 consists of ROM, RAM, flash memory, HDD, etc. Memory 144 stores programs and various data used by the central control unit 142. [Burner device 120] Figure 3 is a diagram illustrating the burner device 120 according to this embodiment. As shown in Figure 3, the burner device 120 includes a main burner 210, a main fuel supply unit 220, a pilot burner 230, and a pilot fuel supply unit 240.

[0033] The main burner 210 is installed in the combustion equipment 110. The outlet of the main burner 210 faces the internal space of the combustion equipment 110. The main burner 210 may be a premixed burner or a premixed burner.

[0034] The main fuel supply unit 220 supplies either fuel gas or hydrocarbons, or both, to the main burner as the main fuel.

[0035] The main fuel supply unit 220 includes an oxidizer supply unit 300, a hydrocarbon supply unit 320, and a fuel gas supply unit 350.

[0036] The oxidizer supply unit 300 supplies air to the main burner 210. In this embodiment, the oxidizer supply unit 300 includes an oxidizer gas supply passage 302, a blower 304, a flow control valve 306, and a flow adjustment valve 308.

[0037] The oxidizer gas supply passage 302 is a passage that connects the blower 304 and the main burner 210. The oxidizer gas supply passage 302 is composed of, for example, piping. The intake side of the blower 304 is open to the atmosphere. The discharge side of the blower 304 is connected to the oxidizer gas supply passage 302. The blower 304 supplies air to the main burner 210 through the oxidizer gas supply passage 302.

[0038] The flow control valve 306 is installed in the oxidizer gas supply passage 302. The opening degree of the flow control valve 306 is adjusted by the flow control unit 170. The flow control valve 306 is, for example, a butterfly valve with a control motor.

[0039] The flow control valve 308 is installed between the flow control valve 306 and the main burner 210 in the oxidizer gas supply passage 302. The flow control valve 308 is, for example, a butterfly valve.

[0040] The hydrocarbon supply unit 320 supplies hydrocarbons to the main burner 210. In this embodiment, the hydrocarbon supply unit 320 includes a hydrocarbon supply passage 322, a pressure regulating valve 324, shut-off valves 326a and 326b, a flow rate regulating valve 328, and a flow rate control valve 330.

[0041] The hydrocarbon supply passage 322 is a flow path connecting the hydrocarbon supply source 160 (main shut-off valve 162) and the main burner 210. The hydrocarbon supply passage 322 is composed of, for example, piping.

[0042] The pressure regulating valve 324 is installed in the hydrocarbon supply passage 322. The pressure regulating valve 324 regulates the pressure of the hydrocarbon supplied downstream to a preset pressure.

[0043] The shut-off valves 326a and 326b (first on / off valves) are installed downstream of the pressure regulating valve 324 in the hydrocarbon supply passage 322. The shut-off valves 326a and 326b open and close the hydrocarbon supply passage 322.

[0044] The flow control valve 328 is located downstream of the shut-off valve 326b in the hydrocarbon supply line 322. The flow control valve 328 is, for example, a butterfly valve.

[0045] The flow control valve 330 is located between the flow regulating valve 328 and the main burner 210 in the hydrocarbon supply line 322. The opening degree of the flow control valve 330 is adjusted by the flow control unit 170. The flow control valve 330 is, for example, a butterfly valve with a control motor.

[0046] The fuel gas supply unit 350 supplies hydrogen to the main burner 210. In this embodiment, the fuel gas supply unit 350 includes a fuel gas supply passage 352, a pressure regulating valve 354, shut-off valves 356a and 356b, a flow rate regulating valve 358, and a flow rate control valve 360.

[0047] The fuel gas supply line 352 is a passage that connects the fuel gas (hydrogen) supply source 150 (main shut-off valve 152) and the hydrocarbon supply line 322. The fuel gas supply line 352 is connected between the flow control valve 330 and the main burner 210 in the hydrocarbon supply line 322. The fuel gas supply line 352 is composed of, for example, piping.

[0048] The pressure regulating valve 354 is installed in the fuel gas supply line 352. The pressure regulating valve 354 regulates the pressure of the hydrogen supplied downstream to a preset pressure.

[0049] The shut-off valves 356a and 356b (second shut-off valves) are installed downstream of the pressure regulating valve 354 in the fuel gas supply passage 352. The shut-off valves 356a and 356b open and close the fuel gas supply passage 352.

[0050] The flow control valve 358 is located downstream of the shut-off valve 356b in the fuel gas supply line 352. The flow control valve 358 is, for example, a butterfly valve.

[0051] The flow control valve 360 ​​is located between the flow regulating valve 358 and the main burner 210 in the fuel gas supply line 352. The opening degree of the flow control valve 360 ​​is adjusted by the flow control unit 170. The flow control valve 360 ​​is, for example, a butterfly valve with a control motor.

[0052] The pilot burner 230 is a burner with a smaller nozzle diameter than the main burner 210. The pilot burner 230 forms a flame toward the flame forming section of the main burner 210. The pilot burner 230 is installed near the main burner 210 in the combustion equipment 110. The nozzle of the pilot burner 230 faces the internal space of the combustion equipment 110. The nozzle of the pilot burner 230 faces, for example, the flow of gas (either fuel gas and hydrocarbons, or both) ejected by the main burner 210. The pilot burner 230 may be a premixed burner or a pre-mixed burner.

[0053] The pilot fuel supply unit 240 supplies hydrocarbons as pilot fuel to the pilot burner 230.

[0054] The pilot fuel supply unit 240 includes an oxidizer supply unit 380 and a hydrocarbon supply unit 390.

[0055] The oxidizer supply unit 380 supplies air to the pilot burner 230. In this embodiment, the oxidizer supply unit 380 includes an oxidizer gas supply passage 382 and a blower 304.

[0056] The oxidizer gas supply passage 382 is a passage that connects the blower 304 and the pilot burner 230. The oxidizer gas supply passage 382 is composed of, for example, piping.

[0057] The hydrocarbon supply unit 390 supplies hydrocarbons to the pilot burner 230. In this embodiment, the hydrocarbon supply unit 390 includes a hydrocarbon supply passage 392, shut-off valves 394a and 394b, and a pressure regulating valve 396.

[0058] The hydrocarbon supply channel 392 is a passage that connects the hydrocarbon supply source 160 (main shut-off valve 162) and the pilot burner 230. The hydrocarbon supply channel 392 is composed of, for example, piping.

[0059] The shut-off valves 394a and 394b are installed in the hydrocarbon supply passage 392. The shut-off valves 394a and 394b open and close the hydrocarbon supply passage 392.

[0060] The pressure regulating valve 396 is located downstream of the shut-off valve 394b in the hydrocarbon supply passage 392. The pressure regulating valve 396 regulates the pressure of the hydrocarbon supplied downstream to a preset pressure.

[0061] [Control by flow control unit 170] Next, we will explain the control of the burner device 120 by the flow control unit 170.

[0062] The flow control unit 170 controls the flow rate of hydrocarbons supplied to the main burner 210 through the hydrocarbon supply passage 322, the flow rate of hydrogen supplied to the main burner 210 through the fuel gas supply passage 352, the flow rate of air supplied to the main burner 210 through the oxidizer gas supply passage 302, and the flow rate of hydrocarbons supplied to the pilot burner 230 through the hydrocarbon supply passage 392 to perform ignition control, operation control, and fire extinguishing control.

[0063] Ignition control is the process of starting the supply of pilot fuel (hydrocarbons) to the pilot burner 230, and then starting the supply of hydrocarbons to the main burner 210. On-board control is the process performed after ignition control. On-board control is the process of supplying hydrogen to the main burner 210. Fire extinguishing control is the process performed after on-board control. Fire extinguishing control is the process of supplying hydrocarbons to the main burner 210.

[0064] In this embodiment, the flow control unit 170 controls the flow rate of air supplied to the main burner 210 by controlling the flow control valve 306. The flow control unit 170 also controls the flow rate of hydrocarbons supplied to the main burner 210 by controlling the shut-off valves 326a, 326b and the flow control valve 330. The flow control unit 170 also controls the flow rate of hydrogen supplied to the main burner 210 by controlling the shut-off valves 356a, 356b and the flow control valve 360. The flow control unit 170 also controls the flow rate of hydrocarbons supplied to the pilot burner 230 by controlling the shut-off valves 394a and 394b.

[0065] Figure 4 is a diagram illustrating the control of the flow control unit 170 according to this embodiment. In Figure 4, the vertical axis represents the flow rate. In Figure 4, the horizontal axis represents time. At time T0, the main shut-off valves 152 and 162 are open, and the shut-off valves 326a, 326b, 356a, 356b, 394a, and 394b are closed. Between time T0 and time T1, the furnace pre-purging (scavenging of the combustion chamber) operation, in which air is supplied from the blower 304, is completed, and the opening of the flow control valve 306 is adjusted to supply air at the ignition flow rate to the main burner 210 while waiting.

[0066] As shown in Figure 4, the flow control unit 170 performs ignition control from time T1 to time T6. The flow control unit 170 also performs operation control from time T6 to time T7. Finally, the flow control unit 170 performs fire extinguishing control from time T7 to time T9. Each control is described in detail below.

[0067] [Ignition control] At time T1, the flow control unit 170 operates the pilot fuel supply unit 240 to start supplying hydrocarbons to the pilot burner 230. In this embodiment, the flow control unit 170 opens the shut-off valves 394a and 394b and ignites the pilot burner using an ignition device (not shown). Hydrocarbons at a flow rate PC are supplied to the hydrocarbon supply passage 392. Flow rate PC is the minimum flow rate required to ignite the pilot burner 230.

[0068] Then, at time T2, a predetermined time after time T1, the flow control unit 170 operates the main fuel supply unit 220 to supply hydrocarbons as the main fuel to the main burner 210. In this embodiment, the flow control unit 170 opens the shut-off valves 326a and 326b to ignite. Also, as shown in Figure 4, the flow control unit 170 controls the flow control valve 330 to control the hydrocarbons supplied to the main burner 210 to a flow rate MC1. The flow rate MC1 is the minimum flow rate required to ignite the main burner 210. As a result, the main burner 210 is ignited.

[0069] From time T2 until time T3, after a predetermined time has elapsed, the flow control unit 170 maintains the hydrocarbon supplied to the main burner 210 at flow rate MC1. Furthermore, at a predetermined timing between time T2 and time T3, the flow control unit 170 closes the shut-off valves 394a and 394b to stop the supply of hydrocarbons to the pilot burner 230, thereby extinguishing the pilot burner 230.

[0070] Then, from time T3 to time T4, after a predetermined time has elapsed, the flow control unit 170 gradually increases the opening of the flow control valves 306 and 330, thereby gradually increasing the amount of air supplied to the main burner 210 and gradually increasing the amount of hydrocarbons from flow rate MC1 to flow rate MC2. Flow rate MC2 is the flow rate required for the rated combustion of the main burner 210.

[0071] From time T4 until time T5, after a predetermined time has elapsed, the flow control unit 170 maintains the opening of the flow control valve 330 to maintain the hydrocarbon supplied to the main burner 210 at a flow rate of MC2.

[0072] Then, from time T5 until time T6, after a predetermined time has elapsed, the flow control unit 170 gradually decreases the opening of the flow control valve 330 to gradually reduce the hydrocarbon supplied to the main burner 210 from flow rate MC2 to 0 (zero), and gradually increases the opening of the flow control valve 360 ​​to gradually increase the hydrogen supplied to the main burner 210 from 0 to flow rate MH. Flow rate MH is the flow rate required for the rated combustion of the main burner 210. During this time, the flow control unit 170 also gradually decreases the opening of the flow control valve 306 to gradually reduce the hydrogen to the set air flow rate for rated combustion. At time T6, the flow control unit 170 closes the shut-off valves 326a and 326b.

[0073] [Control during operation] Then, the flow control unit 170 operates the main fuel supply unit 220 from time T6 until time T7, after a predetermined time has elapsed, to perform in-operation control to supply hydrogen as the main fuel to the main burner 210. For example, the flow control unit 170 controls the opening degree of the flow control valves 306 and 360 according to the value detected by the temperature sensor 130 and the required heat quantity (required temperature) of the combustion equipment 110, thereby controlling the flow rate of air and hydrogen supplied to the main burner 210.

[0074] [Fire extinguishing control] From time T7 until time T8, after a predetermined time has elapsed, the flow control unit 170 operates the main fuel supply unit 220 to supply hydrocarbons as the main fuel to the main burner 210. In this embodiment, at time T7, the flow control unit 170 opens the shut-off valves 326a and 326b. As shown in Figure 4, the flow control unit 170 gradually increases the opening of the flow control valve 330 to gradually increase the amount of hydrocarbons supplied to the main burner 210 from 0 to flow rate MC2, and gradually decreases the opening of the flow control valve 360 ​​to gradually decrease the amount of hydrogen supplied to the main burner 210 from flow rate MH to 0. During this time, the flow control unit 170 also gradually increases the opening of the flow control valve 306 to gradually increase the amount of air flow to the set air flow rate when the hydrocarbon flow rate is MC2. At time T8, the flow control unit 170 closes the shut-off valves 356a and 356b.

[0075] Then, from time T8 until time T9, after a predetermined time has elapsed, the flow control unit 170 maintains the opening of the flow control valve 330 to maintain the hydrocarbon supplied to the main burner 210 at a flow rate of MC2.

[0076] At time T9, the flow control unit 170 closes the shut-off valves 326a and 326b to extinguish the main burner 210, performs post-purge (scavenging of the combustion chamber) operation in the furnace as necessary, and then stops the blower 304.

[0077] [Method of combustion] Next, a combustion method using the combustion system 100 described above will be explained. Figure 5 is a flowchart showing the processing flow of the combustion method according to this embodiment.

[0078] As shown in Figure 5, the combustion method includes ignition S110, in-operation processing S120, and fire extinguishing processing S130.

[0079] [Ignition process S110] In the ignition process S110, ignition control is performed by the flow control unit 170. As described above, the ignition control is to start supplying hydrocarbons to the pilot burner 230, and then to start supplying hydrocarbons to the main burner 210.

[0080] [Processing during operation S120] In the in-operation processing S120, the flow control unit 170 performs in-operation control. As described above, in-operation control is performed after ignition control and is the control of supplying hydrogen to the main burner 210.

[0081] [Fire extinguishing procedure S130] In the fire extinguishing process S130, fire extinguishing control is performed by the flow control unit 170. As described above, fire extinguishing control is performed after the operation control and is a control that supplies hydrocarbons to the main burner 210.

[0082] As described above, in the combustion system 100 and combustion method according to this embodiment, hydrocarbons are supplied to the fuel gas supply passage 352 via the hydrocarbon supply passage 322 during fire suppression control. This makes it possible to replace hydrogen with hydrocarbons in the fuel gas supply passage 352. Therefore, even if hydrogen is supplied to the fuel gas supply passage 352 during the next ignition control, it is possible to avoid the formation of a combustible mixture of hydrogen and air in the fuel gas supply passage 352. For this reason, the combustion system 100 can prevent flashback.

[0083] Furthermore, in ignition control, the combustion system 100 supplies hydrocarbons to the fuel gas supply passage 352 via the hydrocarbon supply passage 322 before starting the hydrogen supply. Therefore, it is possible to avoid the formation of a combustible mixture of hydrogen and air in the fuel gas supply passage 352.

[0084] Thus, the combustion system 100, with its simple configuration of filling the fuel gas supply passage 352 with hydrocarbons after stopping the hydrogen supply and before starting the hydrogen supply, can minimize the risk of equipment damage due to flashback without installing flashback prevention and suppression devices such as flame arresters and inert gas supply devices in the fuel gas supply passage 352. As a result, the combustion system 100 can prevent flashback at low cost. Furthermore, a flame arrester is merely a device that minimizes flashback and cannot be considered a measure that essentially prevents flashback from occurring. In contrast, the combustion system 100 can prevent flashback from occurring.

[0085] Furthermore, as described above, the burner device 120 is equipped with a pilot burner 230, and the flow control unit 170 operates the pilot fuel supply unit 240 to start supplying pilot fuel (hydrocarbons) to the pilot burner 230 during ignition control. After starting to supply pilot fuel to the pilot burner 230, the main fuel supply unit 220 operates to start supplying hydrocarbons to the main burner 210. As a result, the burner device 120 can stably perform the ignition operation of the main burner 210 during ignition control.

[0086] Furthermore, as described above, the flow control unit 170 stops the operation of the pilot fuel supply unit 240 during operation control. In other words, the flow control unit 170 operates the pilot fuel supply unit 240 only during ignition control. This shortens the combustion time of hydrocarbons. Consequently, it becomes possible to reduce CO2 emissions.

[0087] [First variation] In the above embodiment, an example was given in which the pilot fuel supply unit 240 supplies hydrocarbons as pilot fuel to the pilot burner 230. However, the pilot fuel supply unit 440 may supply hydrogen (fuel gas) as pilot fuel to the pilot burner 230.

[0088] Figure 6 illustrates a burner device 420 according to the first modified example. As shown in Figure 6, the burner device 420 includes a main burner 210, a main fuel supply unit 220, a pilot burner 230, and a pilot fuel supply unit 440. Components that are substantially the same as those in the burner device 120 are given the same reference numerals and their descriptions are omitted.

[0089] In the first modification, the pilot fuel supply unit 440 supplies fuel gas (hydrogen) as pilot fuel to the pilot burner 230.

[0090] The pilot fuel supply unit 440 includes an oxidizer supply unit 380 and a fuel gas supply unit 450.

[0091] The fuel gas supply unit 450 supplies hydrogen to the pilot burner 230. In this embodiment, the fuel gas supply unit 450 includes a fuel gas supply passage 452, shut-off valves 454a and 454b, and a pressure regulating valve 456.

[0092] The fuel gas supply line 452 is a passage that connects the hydrogen supply source 150 (main shut-off valve 152) and the pilot burner 230. The fuel gas supply line 452 is composed of, for example, piping.

[0093] The shut-off valves 454a and 454b are installed in the fuel gas supply passage 452. The shut-off valves 454a and 454b open and close the fuel gas supply passage 452.

[0094] The pressure regulating valve 456 is located downstream of the shut-off valve 454b in the fuel gas supply line 452. The pressure regulating valve 456 regulates the pressure of the hydrogen supplied downstream to a preset pressure.

[0095] [Control by flow control unit 170] Next, we will explain the control of the burner device 420 by the flow control unit 170.

[0096] Figure 7 is a diagram illustrating the control of the flow rate control unit 170 according to the first modified example. In Figure 7, the vertical axis represents the flow rate. In Figure 7, the horizontal axis represents time.

[0097] As shown in Figure 7, in the first modified example, the flow control unit 170 operates the pilot fuel supply unit 440 at ignition control time T1 to start supplying hydrogen to the pilot burner 230. In the first modified example, the flow control unit 170 opens the shut-off valves 454a and 454b and ignites using an ignition device (not shown). Hydrogen at a flow rate PH is supplied to the fuel gas supply passage 452. Flow rate PH is the minimum flow rate required to ignite the pilot burner 230.

[0098] Furthermore, the flow control unit 170 closes the shut-off valves 454a and 454b at a predetermined timing between time T2 and time T3, stopping the supply of hydrogen to the pilot burner 230 and extinguishing the pilot burner 230.

[0099] As described above, the flow control unit 170 of the first modified example supplies hydrogen to the pilot burner 230 during ignition control. This allows the burner device 420 of the first modified example to avoid supplying hydrocarbons to the pilot burner 230. Therefore, the burner device 420 of the first modified example can further reduce CO2 emissions compared to the above embodiment.

[0100] [Second variation] In the above embodiment, an example was given in which the pilot fuel supply unit 240 supplies hydrocarbons to the pilot burner 230 only during ignition control. However, the pilot fuel supply unit 240 may also supply hydrocarbons to the pilot burner 230 during operation control and fire extinguishing control, in addition to ignition control.

[0101] Figure 8 illustrates the control of the flow rate control unit 170 according to the second modified example. In Figure 8, the vertical axis represents the flow rate. In Figure 8, the horizontal axis represents time.

[0102] [Ignition control] In the second modification, the flow control unit 170 operates the pilot fuel supply unit 240 at time T1 to start supplying hydrocarbons to the pilot burner 230. In the second modification, the flow control unit 170 also opens the shut-off valves 394a and 394b and ignites using an ignition device (not shown). Hydrocarbons at a flow rate PC are supplied to the hydrocarbon supply passage 392.

[0103] [Control during operation] The flow control unit 170 then maintains the supply of hydrocarbons to the pilot burner 230 until a predetermined timing after time T6, when the supply of hydrocarbons to the main burner 210 is stopped. At the predetermined timing, it closes the shut-off valves 394a and 394b to stop the supply of hydrocarbons to the pilot burner 230 and extinguishes the pilot burner 230.

[0104] Furthermore, the flow control unit 170 opens the shut-off valves 394a and 394b at a predetermined timing prior to the time T7 when the supply of hydrocarbons to the main burner 210 is resumed, that is, at a predetermined timing prior to the start of fire extinguishing control, thereby resuming the supply of hydrocarbons to the pilot burner 230.

[0105] [Fire extinguishing control] At time T9, when the supply of hydrocarbons to the main burner 210 is to be stopped, the flow control unit 170 closes the shut-off valves 394a and 394b to stop the supply of hydrocarbons to the pilot burner 230 and extinguishes the pilot burner 230.

[0106] As described above, the burner device 120 according to the second modification maintains the supply of hydrocarbons to the pilot burner 230 until a predetermined timing after the time T6 in which the supply of hydrocarbons to the main burner 210 is stopped. This makes it possible for the burner device 120 to stabilize the combustion by the main burner 210, at least while the flow rate of hydrocarbons supplied to the main burner 210 is gradually decreasing and the flow rate of hydrogen is gradually increasing.

[0107] Furthermore, the burner device 120 according to the second modification restarts the supply of hydrocarbons to the pilot burner 230 from a predetermined timing prior to the time T7 when fire suppression control is initiated. This makes it possible for the burner device 120 to stabilize combustion by the main burner 210, at least while the flow rate of hydrocarbons supplied to the main burner 210 is gradually increasing and the flow rate of hydrogen is gradually decreasing.

[0108] [Third variation] In the second modification described above, an example was given in which the pilot fuel supply unit 240 supplies hydrocarbons as pilot fuel to the pilot burner 230. However, the pilot fuel supply unit 440 may also supply hydrogen (fuel gas) as pilot fuel to the pilot burner 230.

[0109] Figure 9 is a diagram illustrating the control of the flow rate control unit 170 according to the third modified example. In Figure 9, the vertical axis represents the flow rate. In Figure 9, the horizontal axis represents time.

[0110] [Ignition control] In the third modification, the flow control unit 170 operates the pilot fuel supply unit 440 at time T1 to start supplying hydrogen to the pilot burner 230. In the third modification, the flow control unit 170 also opens the shut-off valves 454a and 454b and ignites using an ignition device (not shown). Hydrogen at a flow rate of PH is supplied to the fuel gas supply line 452.

[0111] [Control during operation] The flow control unit 170 then maintains the supply of hydrogen to the pilot burner 230 until a predetermined timing after time T6, when the supply of hydrocarbons to the main burner 210 is stopped. At the predetermined timing, it closes the shut-off valves 454a and 454b to stop the supply of hydrogen to the pilot burner 230 and extinguishes the pilot burner 230.

[0112] Furthermore, the flow control unit 170 opens the shut-off valves 454a and 454b at a predetermined timing prior to the time T7 when the supply of hydrocarbons to the main burner 210 is resumed, that is, at a predetermined timing prior to the start of fire extinguishing control, thereby resuming the supply of hydrogen to the pilot burner 230.

[0113] [Fire extinguishing control] At time T9, when the supply of hydrocarbons to the main burner 210 is stopped, the flow control unit 170 closes the shut-off valves 454a and 454b to stop the supply of hydrogen to the pilot burner 230 and extinguishes the pilot burner 230.

[0114] As described above, the burner device 420 according to the third modification maintains the supply of hydrogen to the pilot burner 230 until a predetermined timing after the time T6 in which the supply of hydrocarbons to the main burner 210 is stopped. This makes it possible for the burner device 420 to stabilize the combustion by the main burner 210, at least while the flow rate of hydrocarbons supplied to the main burner 210 is gradually decreasing and the flow rate of hydrogen is gradually increasing.

[0115] Furthermore, the burner device 420 according to the third modification restarts the supply of hydrogen to the pilot burner 230 at a predetermined timing prior to the time T7 when fire suppression control is initiated. This makes it possible for the burner device 420 to stabilize combustion by the main burner 210, at least while the flow rate of hydrocarbons supplied to the main burner 210 is gradually increasing and the flow rate of hydrogen is gradually decreasing.

[0116] Furthermore, the burner device 420 according to the third modification can further reduce CO2 emissions compared to the burner device 120 according to the second modification.

[0117] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0118] For example, in the above embodiment and the first to third modifications, the burner devices 120 and 420 are configured to include a pilot burner 230 and pilot fuel supply units 240 and 440. However, the pilot burner 230 and pilot fuel supply units 240 and 440 are not essential components. If the pilot burner 230 and pilot fuel supply units 240 and 440 are not provided, the flow control unit 170 operates the main fuel supply unit 220 to supply hydrocarbons as the main fuel to the main burner 210 and performs ignition control. After the ignition control, the flow control unit 170 operates the main fuel supply unit 220 to supply fuel gas (hydrogen) to the main burner 210 and performs in-operation control. After the in-operation control, the flow control unit 170 operates the main fuel supply unit 220 to supply hydrocarbons as the main fuel to the main burner 210 and performs fire extinguishing control. Even in configurations without pilot burners 230 and pilot fuel supply units 240 and 440, the combustion system can supply hydrocarbons to the fuel gas supply line 352 via the hydrocarbon supply line 322 during fire suppression control. This allows for the replacement of hydrogen with hydrocarbons in the fuel gas supply line 352. Therefore, even if hydrogen is supplied to the fuel gas supply line 352 during the next ignition control, it is possible to avoid the formation of a combustible mixture of hydrogen and air in the fuel gas supply line 352. Furthermore, even in configurations without pilot burners 230 and pilot fuel supply units 240 and 440, the combustion system also supplies hydrocarbons to the fuel gas supply line 352 via the hydrocarbon supply line 322 before starting the hydrogen supply during ignition control. Therefore, it is possible to avoid the formation of a combustible mixture of hydrogen and air in the fuel gas supply line 352.

[0119] Furthermore, in the above embodiments and the first to third modifications, the case in which the flow control unit 170 performs ignition control was given as an example. However, if the flow control unit 170 can perform fire extinguishing control and operation control, ignition control may be omitted. Even in such a configuration, even if hydrogen is supplied to the fuel gas supply passage 352 during the next ignition control, it is possible to avoid the formation of a combustible mixture of hydrogen and air in the fuel gas supply passage 352.

[0120] Furthermore, in the above embodiments and the first to third modifications, the flow control unit 170, in ignition control, takes the example of gradually reducing the flow rate of hydrocarbons and gradually reducing the flow rate of hydrogen when switching the main fuel supplied to the main burner 210 from hydrocarbons to hydrogen. However, in ignition control, the flow control unit 170 may, by referring to the value detected by the temperature sensor 130, open the shut-off valves 356a and 356b (second shut-off valves) to start supplying hydrogen and close the shut-off valves 326a and 326b (first shut-off valves) to stop supplying hydrocarbons when the internal temperature of the combustion equipment 110 in which the main burner 210 is installed reaches a predetermined temperature or higher. This makes it possible to omit the flow control valve 330.

[0121] Similarly, in the above embodiments and the first to third modifications, the flow control unit 170, in fire extinguishing control, takes as an example the case in which, when switching the main fuel supplied to the main burner 210 from hydrogen to hydrocarbons, gradually reduces the flow rate of hydrogen and gradually reduces the flow rate of hydrocarbons. However, in fire extinguishing control, the flow control unit 170 may operate the pilot fuel supply units 240 and 440 to start supplying pilot fuel to the pilot burner 230, and after starting to supply pilot fuel to the pilot burner 230, open the shut-off valves 326a and 326b (first on-off valves) to start supplying hydrocarbons, and close the shut-off valves 356a and 356b (second on-off valves) to stop supplying hydrogen.

[0122] Furthermore, in the second and third modifications described above, the flow control unit 170 was shown as an example in which it stops supplying pilot fuel to the pilot burner 230 for a predetermined period during operation control. However, the flow control unit 170 may operate the pilot fuel supply units 240 and 440 throughout ignition control, operation control, and fire extinguishing control to continue supplying pilot fuel to the pilot burner 230. In this case, it becomes possible to stabilize the combustion by the main burner 210 throughout ignition control, operation control, and fire extinguishing control. [Explanation of symbols]

[0123] 100 Combustion Systems 110 Combustion equipment (furnace) 170 Flow Control Unit (Control Unit) 210 Main Burner 220 Main fuel supply unit 230 Pilot Burner 240 Pilot Fuel Supply Unit 322 Hydrocarbon supply routes 326a Shut-off valve (first shut-off valve) 326b Shut-off valve (first shut-off valve) 352 Fuel gas supply line 356a Shut-off valve (second shut-off valve) 356b Shut-off valve (second shut-off valve) 440 Pilot Fuel Supply Unit

Claims

1. Main burner and A main fuel supply unit that supplies a fuel gas containing at least hydrogen or acetylene, and one or both of a hydrocarbon, to the main burner as the main fuel, A control unit that controls the main fuel supply unit, Equipped with, The control unit, The main fuel supply unit is operated to perform ignition control, supplying the hydrocarbon as the main fuel to the main burner. After the ignition control, the main fuel supply unit is operated to supply the fuel gas as the main fuel to the main burner in an in-operation control manner. After the aforementioned in-operation control, the main fuel supply unit is activated to perform fire extinguishing control, supplying the hydrocarbon as the main fuel to the main burner. The aforementioned main fuel supply unit is A hydrocarbon supply path connecting the hydrocarbon source and the main burner, A fuel gas supply line connecting the fuel gas supply source and the hydrocarbon supply line, A first on / off valve provided in the hydrocarbon supply passage, A second on / off valve is provided in the fuel gas supply line, It has, The control unit, in the ignition control, opens the second on-off valve and closes the first on-off valve when the internal temperature of the furnace in which the main burner is provided rises above a predetermined temperature, in a combustion system.

2. A pilot burner with a smaller diameter than the main burner, A pilot fuel supply unit that supplies either or both of the fuel gas and the hydrocarbon to the pilot burner as pilot fuel, Equipped with, The control unit, In the ignition control described above, the pilot fuel supply unit is operated to start supplying the pilot fuel to the pilot burner, The combustion system according to claim 1, wherein after starting to supply the pilot fuel to the pilot burner, the main fuel supply unit is operated to start supplying the hydrocarbon to the main burner.

3. The pilot fuel supply unit supplies the fuel gas as the pilot fuel to the pilot burner. The combustion system according to claim 2, wherein the control unit operates the pilot fuel supply unit to continue supplying the pilot fuel to the pilot burner during the ignition control, the operation control, and the fire extinguishing control.

4. The combustion system according to claim 2, wherein the control unit stops the operation of the pilot fuel supply unit during the operation control.

5. The control unit is In the fire extinguishing control described above, the pilot fuel supply unit is operated to start supplying the pilot fuel to the pilot burner, The combustion system according to claim 2, wherein after starting to supply the pilot fuel to the pilot burner, the first on-off valve is opened and the second on-off valve is closed.

6. Main burner and A main fuel supply unit that supplies a fuel gas containing at least hydrogen or acetylene, and one or both of a hydrocarbon, to the main burner as the main fuel, A pilot burner with a smaller diameter than the main burner, A pilot fuel supply unit that supplies the aforementioned fuel gas to the pilot burner as pilot fuel, A control unit that controls the main fuel supply unit and the pilot fuel supply unit, Equipped with, The aforementioned main fuel supply unit is A hydrocarbon supply path connecting the hydrocarbon source and the main burner, A fuel gas supply line connecting the fuel gas supply source and the hydrocarbon supply line, It has, The control unit, The pilot fuel supply unit is activated to begin supplying the pilot fuel to the pilot burner, and after the pilot fuel has been supplied to the pilot burner, the main fuel supply unit is activated to begin supplying the hydrocarbon as the main fuel to the main burner, thereby performing ignition control. After the ignition control, the main fuel supply unit is operated to supply the fuel gas as the main fuel to the main burner in an in-operation control manner. After the aforementioned in-operation control, the main fuel supply unit is activated to perform fire extinguishing control, supplying the hydrocarbon as the main fuel to the main burner. A combustion system in which the control unit operates the pilot fuel supply unit to continue supplying the pilot fuel to the pilot burner during the ignition control, the operation control, and the fire extinguishing control.

7. Main burner and A main fuel supply unit that supplies a fuel gas containing at least hydrogen or acetylene, and one or both of a hydrocarbon, to the main burner as the main fuel, A pilot burner with a smaller diameter than the main burner, A pilot fuel supply unit that supplies either or both of the fuel gas and the hydrocarbon to the pilot burner as pilot fuel, A control unit that controls the main fuel supply unit and the pilot fuel supply unit, Equipped with, The aforementioned main fuel supply unit is A hydrocarbon supply path connecting the hydrocarbon source and the main burner, A fuel gas supply line connecting the fuel gas supply source and the hydrocarbon supply line, A first on / off valve provided in the hydrocarbon supply passage, A second on / off valve is provided in the fuel gas supply line, It has, The control unit, The pilot fuel supply unit is activated to begin supplying the pilot fuel to the pilot burner, and after the pilot fuel has been supplied to the pilot burner, the main fuel supply unit is activated to begin supplying the hydrocarbon as the main fuel to the main burner, thereby performing ignition control. After the ignition control, the main fuel supply unit is operated to supply the fuel gas as the main fuel to the main burner in an in-operation control manner. After the aforementioned in-operation control, the main fuel supply unit is activated to perform fire extinguishing control, supplying the hydrocarbon as the main fuel to the main burner. The control unit, In the fire extinguishing control described above, the pilot fuel supply unit is operated to start supplying the pilot fuel to the pilot burner, A combustion system that, after starting to supply the pilot fuel to the pilot burner, opens the first on-off valve and closes the second on-off valve.

8. A main burner, A hydrocarbon supply path connecting the hydrocarbon source and the main burner, A fuel gas supply line connecting a fuel gas supply source containing at least hydrogen or acetylene to the hydrocarbon supply line, A first on / off valve provided in the hydrocarbon supply passage, A second on / off valve is provided in the fuel gas supply line, A combustion method using a combustion system comprising: The ignition control is performed to supply the hydrocarbon to the main burner, After the ignition control, an in-operation control is performed to supply the fuel gas to the main burner. After the aforementioned in-operation control, fire extinguishing control is performed to supply the hydrocarbon to the main burner. Includes, In the ignition control described above, when the internal temperature of the furnace in which the main burner is installed reaches a predetermined temperature or higher, the second on-off valve is opened and the first on-off valve is closed. Method of combustion.

9. A main burner, A hydrocarbon supply path connecting the hydrocarbon source and the main burner, A fuel gas supply line connecting a fuel gas supply source containing at least hydrogen or acetylene to the hydrocarbon supply line, A pilot burner with a smaller diameter than the main burner, A combustion method using a combustion system comprising: The ignition control involves starting the supply of pilot fuel to the pilot burner, and after starting the supply of pilot fuel to the pilot burner, starting the supply of hydrocarbons to the main burner. After the ignition control, an in-operation control is performed to supply the fuel gas to the main burner. After the aforementioned in-operation control, fire extinguishing control is performed to supply the hydrocarbon to the main burner. Includes, The fuel gas is supplied to the pilot burner as the pilot fuel. The supply of pilot fuel to the pilot burner is continued throughout the ignition control, the operation control, and the fire extinguishing control. Method of combustion.

10. A main burner, A hydrocarbon supply path connecting the hydrocarbon source and the main burner, A fuel gas supply line connecting a fuel gas supply source containing at least hydrogen or acetylene to the hydrocarbon supply line, A first on / off valve provided in the hydrocarbon supply passage, A second on / off valve is provided in the fuel gas supply line, A pilot burner with a smaller diameter than the main burner, A combustion method using a combustion system comprising: The ignition control involves starting the supply of pilot fuel to the pilot burner, and after starting the supply of pilot fuel to the pilot burner, starting the supply of hydrocarbons to the main burner. After the ignition control, an in-operation control is performed to supply the fuel gas to the main burner. After the aforementioned in-operation control, fire extinguishing control is performed to supply the hydrocarbon to the main burner. Includes, In the fire extinguishing control described above, the supply of the pilot fuel to the pilot burner is initiated. After starting to supply the pilot fuel to the pilot burner, the first on-off valve is opened and the second on-off valve is closed. A combustion method wherein the pilot fuel is either the fuel gas or the hydrocarbon, or both.

Images