WO2023149024A1

WO2023149024A1 - Combustion device and combustion system

Info

Publication number: WO2023149024A1
Application number: PCT/JP2022/039189
Authority: WO
Inventors: 恭幸小林
Original assignee: 株式会社カシワテック
Priority date: 2022-02-04
Filing date: 2022-10-20
Publication date: 2023-08-10
Also published as: JP2023114413A; JP7083211B1; JP2023114324A

Abstract

Provided are a combustion device and a combustion system with an increased rate of use of ammonia as a fuel. A combustion device 100 comprises: a combustion space forming part 1 that forms a first combustion space S1, in which ammonia serving as a first fuel, or a second fuel other than ammonia, is treated as fuel and made to combust; a fuel supply part 2 that supplies fuel to the combustion space forming part 1; an ammonia supply part 3 that supplies ammonia to the fuel supply part 2; and a second fuel supply part 4 that supplies the second fuel to the fuel supply part, wherein the ammonia supply part 3 has a heat exchange part 30 heating the ammonia, and supplies the ammonia which was heated by the heat exchange part 30 to the fuel supply part 2.

Description

Combustion device and combustion system

The present disclosure relates to combustion devices and combustion systems.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2010-269788) discloses that during the transportation of hydrocarbonaceous products by marine vessels, there is a potential for fire and explosion on board the vessel, so fire and explosion should be avoided during transportation. It states that the SOLAS Convention requires ships such as tankers to be equipped with an inert gas system in order to take preventative measures. It also states that the exhaust from a diesel engine may be scrubbed and the scrubbed gas may be used as an inert gas. Also, while scrubbed gas is an inexpensive inert gas source, scrubbing systems may not be completely effective in removing carbon dioxide, nitrogen oxides, sulfur oxides, and the dioxide in scrubbed gas It is noted that carbon can lead to tank corrosion.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2018-96680) describes a coal combustion apparatus capable of co-firing ammonia. The coal combustion apparatus includes a tubular furnace body and a burner connected to an end portion of the tubular furnace body 1 . The burner is provided with a mixture gas flow path body having a double-tube structure, and an ammonia flow path for sending ammonia as a fuel is provided at the center of the mixture gas flow path body. A pulverized coal channel for feeding pulverized coal as a fuel is provided outside the ammonia channel, and a pulverized coal supply channel for conveying pulverized coal and primary air to the pulverized coal channel is connected to the pulverized coal channel. . A two-stage combustion air supply means for supplying air for two-stage combustion is provided on the downstream side of the furnace body. Compared to hydrogen and other hydrocarbon fuels, ammonia has the problem of being difficult to ignite and burning slowly. Can be used as part of fuel. It is described that when pulverized coal and ammonia are used as fuel, ammonia is used, for example, at a calorific value of 20%.

Non-Patent Document 1 describes an inert gas device that produces a gas with a low oxygen concentration as an inert gas. As an inert gas device, it is possible to produce cleaner inert gas by using boiler exhaust gas to produce inert gas, or by burning fuel independently to produce inert gas. A device is described. It is exemplified that the inert gas produced by these inert gas devices is used to prevent ignition and explosion in cargo tanks of tankers carrying combustible hazardous materials such as crude oil.

JP 2010-269788 A JP 2018-96680 A

For the purpose of reducing emissions of greenhouse gases such as carbon dioxide (so-called carbon neutrality), it is desired to reduce the amount of fossil fuels used in various combustion devices. In addition, from the viewpoint of use as an inert gas generator for ships, it is desirable to reduce the amount of carbon dioxide emissions. As an example of a fuel that replaces fossil fuel in a combustion apparatus, a technique of mixing and burning a fossil fuel and ammonia is known, as described in Patent Document 2, for example. However, in the prior art, the rate of use of ammonia as a fuel (for example, the calorie ratio) could not be sufficiently increased, and the reduction of carbon dioxide emissions was not sufficient. Therefore, it is desired to provide a combustion apparatus with a high usage rate of ammonia.

The present disclosure has been made in view of such circumstances, and its purpose is to provide a combustion device and a combustion system in which the usage rate of ammonia as fuel is increased.

A combustion apparatus according to the present disclosure for achieving the above object includes:
a combustion space forming part that forms a first combustion space for burning ammonia as a first fuel or a second fuel different from the ammonia as a fuel;
a fuel supply unit that supplies the fuel to the combustion space forming unit;
an ammonia supply unit that supplies the ammonia to the fuel supply unit;
a second fuel supply unit that supplies the second fuel to the fuel supply unit;
The ammonia supply unit is
Having a heat exchange unit that heats the ammonia,
The ammonia heated by the heat exchange section is supplied to the fuel supply section.

A combustion system according to the present disclosure for achieving the above object includes:
a combustion device as described above;
a combustion vessel in which the combustion device is mounted and which forms a second combustion space;
The combustion vessel accommodates the combustion space forming portion in the second combustion space.

According to the present disclosure, it is possible to provide a combustion device and a combustion system that increase the usage rate of ammonia as fuel.

1 is an explanatory diagram of the configuration of a combustion system according to a first embodiment; FIG. FIG. 4 is an explanatory diagram of the configuration of the combustion system of Modification 1 of the first embodiment; FIG. 7 is an explanatory diagram of the configuration of the combustion system of Modification 2 of the first embodiment; It is an explanatory view of the configuration of the combustion system of the second embodiment.

A combustion device and a combustion system according to an embodiment of the present disclosure will be described based on the drawings.

(First embodiment)
(Description of overview)
FIG. 1 shows an explanatory diagram of the configuration of a combustion system 200 according to this embodiment.

The combustion system 200 includes a combustion device 100 and a combustion vessel 9 to which the combustion device 100 is attached.

The combustion device 100 supplies fuel to the combustion space forming part 1 that forms a first combustion space S1 in which ammonia as the first fuel or a second fuel other than ammonia is burned as fuel, and the combustion space forming part 1. A fuel supply unit 2 , an ammonia supply unit 3 that supplies ammonia to the fuel supply unit 2 , and a second fuel supply unit 4 that supplies a second fuel to the fuel supply unit 2 are provided.

The ammonia supply unit 3 has a heat exchange unit 30 that heats ammonia, and supplies the ammonia heated by the heat exchange unit 30 to the fuel supply unit 2 .

A combustion vessel 9 to which the combustion device 100 is attached forms a furnace space S. The combustion vessel 9 accommodates the combustion space forming part 1 of the combustion device 100 in the furnace space S.

The combustion device 100 and the combustion system 200 having the same can realize combustion with a high usage rate of ammonia as fuel. For example, not only can ammonia and a second fuel be mixed and burned, but ammonia alone can be burned.

Combustion with ammonia alone in the combustion device 100 refers to a case where the fuel supplied to the combustion device 100 during combustion is only ammonia.

(Description of each part)
As described above, the combustion apparatus 100 includes a combustion space forming section 1, a fuel supply section 2 that supplies fuel and an oxygen carrier gas to the combustion space forming section 1, an ammonia supply section 3, a second fuel supply section 4, In addition to , an oxygen carrier gas supply unit 20 that supplies oxygen carrier gas to the fuel supply unit 2 and a return line 5 that supplies combustion exhaust gas to the fuel supply unit 2 are provided. The combustion device 100 is a burner that burns ammonia as a first fuel or a second fuel other than ammonia as a fuel. Examples of the second fuel are fossil fuels, for example, petroleum fuels such as heavy oil A (hereinafter simply referred to as heavy oil), and hydrocarbon gas fuels such as natural gas and propane gas. A case where the second fuel is heavy oil will be described below as an example.

The combustion system 200 includes the combustion device 100, an ammonia supply system 6 that supplies ammonia to the combustion device 100, a second fuel supply system 7 that supplies heavy oil to the combustion device 100, and an oxygen carrier gas to the combustion device 100. It is provided with an oxygen carrier gas supply system 8 that supplies oxygen, a combustion vessel 9 in which a combustion device 100 is mounted, and a controller C that controls the operation of each part. An oxygen carrier gas is a gas that carries oxygen for combustion (ie, a gas containing oxygen), and in this embodiment is air as an example. A case where the oxygen carrier gas is air will be described below as an example.

The control unit C is a functional unit that controls the operation of the combustion system 200 and serves as a central control mechanism of the combustion system 200 . The control unit C receives information on operating conditions and detection conditions from each unit and sensors of the combustion system 200, and also sends operation commands to each unit to control their operations.

The control unit C is implemented in hardware or software by a CPU or a program (software) that causes the CPU to implement control of the combustion system 200 . In this embodiment, the control unit C is implemented by a computer such as a personal computer or a PLC and control software stored in its storage unit. The control unit C is communicably connected to each unit of the combustion system 200 via a communication path configured by a port, a bus, a wired or wireless network (including an Internet line), or the like. As the storage unit, a storage device or storage medium that can be used in a computer, such as a flash memory such as a so-called USB memory, a hard disk, an optical disk such as an SSD or a CDROM, etc., can generally be used.

The combustion vessel 9 is a vessel that forms a space for combustion by the combustion device 100 (hereinafter referred to as a furnace space S). The combustion vessel 9 is formed in a cylindrical shape with a bottom, as an example. FIG. 1 shows a case where the combustion vessel 9 has a bottom wall 91 of a cylinder with a bottom and a tubular wall portion 90 , and a combustion device 100 is fixed to the bottom wall 91 . The combustion vessel 9 may have a temperature sensor 99 that measures the temperature of the flue gas. The combustion space forming part 1 of the combustion device 100 is fixed inside the cylinder of the combustion vessel 9 on the bottom wall 91 and accommodated in the furnace space S. As shown in FIG. The fuel supply portion 2 is fixed to the bottom wall 91 on the side opposite to the side to which the combustion space forming portion 1 is fixed. In the following description, the flow direction of the supply of the fuel and the oxygen carrier gas from the fuel supply section 2 to the combustion space forming section 1 and the direction along this may be simply referred to as the flow direction. Also, the downstream side of the flow of the fuel or oxygen carrier gas is simply referred to as the downstream side, and the upstream side of the flow is simply referred to as the upstream side. In other words, the combustion space forming portion 1 is downstream when viewed from the fuel supply portion 2 . Conversely, when viewed from the combustion space forming portion 1, the fuel supply portion 2 is on the upstream side.

The temperature of the combustion exhaust gas in the combustion vessel 9 can reach 1200°C to 1500°C in the combustion state of heavy oil alone. The temperature of the flue gas in the combustion vessel 9 can reach around 800° C. in a mixed combustion state of heavy oil and ammonia. The temperature of the flue gas in the combustion vessel 9 can reach 600° C. to 800° C. under ammonia-only combustion conditions.

The combustion space forming portion 1 has a tubular portion 10 and a pilot burner 19 fixed to the tubular portion 10 .

The tubular portion 10 is a wall member that partitions the first combustion space S1 for burning fuel within the furnace space S. The tubular portion 10 is a so-called burner cone. The inner space of the cylinder of the tubular portion 10 is the first combustion space S1. Fuel and air are supplied from the fuel supply section 2 to the first combustion space S<b>1 of the cylindrical section 10 . The cylindrical portion 10 has a circular cross section along the axial direction of the cylinder, that is, along the flow direction. The tubular portion 10 may have a trumpet-shaped cross section along the flow direction in which the inner diameter increases from the upstream side to the downstream side.

The pilot burner 19 is an ignition device that ignites and burns a pilot flame within the first combustion space S1 when the combustion device 100 starts combustion. When starting combustion by the combustion device 100 , the pilot burner 19 ignites the fuel supplied from the fuel supply section 2 to the tubular portion 10 with the pilot light, thereby realizing the start of combustion by the combustion device 100 . After ignition by the pilot burner 19 , the combustion device 100 is able to continue combustion without pilot light by the pilot burner 19 due to the fuel and air that are continuously supplied to the tubular portion 10 .

The flame generated in the combustion space forming part 1 burns inside the combustion vessel 9, that is, inside the furnace space S. A part of the combustion exhaust gas generated within the combustion vessel 9 is returned to the fuel supply section 2 as will be described later. Other combustion exhaust gases are discharged outside the combustion system 200 after being discharged from the combustion vessel 9 . The flue gas discharged from the combustion system 200 is purified as necessary and used as an inert gas for ships and the like. Moreover, the flue gas discharged from the combustion system 200 is used as a heat source as needed.

An ammonia supply unit 3, a second fuel supply unit 4 that supplies heavy oil, an oxygen carrier gas supply unit 20, and a return line 5 are connected to the fuel supply unit 2, and ammonia, heavy oil, air, and combustion are connected. Exhaust gas can be supplied. The fuel supply section 2 supplies the supplied ammonia or a mixed gas of heavy oil and air to the combustion space forming section 1 . The ammonia supply unit 3, the second fuel supply unit 4, and the oxygen carrier gas supply unit 20 are supplied with ammonia and heavy oil from an ammonia supply system 6, a second fuel supply system 7, and an oxygen carrier gas supply system 8, which will be described later, respectively. and air are supplied.

The fuel supply unit 2 has a mixing mechanism that mixes ammonia or heavy oil, air, and flue gas to form a mixed gas. FIG. 1 illustrates a case where the mixing mechanism is an ejector mechanism that mixes air and heavy oil or ammonia with the energy of the air stream supplied from the oxygen carrier gas supply system 8 and feeds the mixed gas into the combustion space forming section 1. is shown.

The fuel supply unit 2 includes, as the ejector mechanism described above, a suction chamber 22, a nozzle portion 21 for blowing air into the suction chamber 22, and a diffuser portion that communicates and connects the downstream side of the suction chamber 22 and the upstream side of the tubular portion 10. 23.

The suction chamber 22 is a container that forms a space where air, fuel, etc. join. The nozzle part 21 has a nozzle shape in which the tip side from which air is blown out is narrowed, and the tip of the nozzle is accommodated in the suction chamber 22 . An oxygen carrier gas supply unit 20 is connected to the nozzle unit 21 to supply pressurized air.

In the present embodiment, the diffuser portion 23 is an opening formed in the suction chamber 22 that communicates the inside of the suction chamber 22 with the inside of the cylindrical portion 10, and is located downstream of the nozzle portion 21 in the air injection direction. placed on the side. The opening diameter of the diffuser portion 23 is larger than the opening diameter of the tip of the nozzle portion 21 .

In the fuel supply portion 2, the nozzle portion 21, the suction chamber 22, the diffuser portion 23, and the pressurized air flow create a venturi effect, and the fluid in the suction chamber 22 is forced through the diffuser portion 23 into a cylinder. They are dispersed and mixed while being attracted to the shape portion 10 side to form a mixed gas (a gaseous mixed gas or a gas-liquid multiphase flow of atomized heavy oil and air or the like). In addition, due to this attraction, the pressure inside the suction chamber 22 becomes negative.

In addition to the nozzle portion 21 as described above, the suction chamber 22 is connected to the ammonia supply portion 3, the second fuel supply portion 4 that supplies heavy oil, and the return path 5, and supplies air, ammonia, and heavy oil. , and flue gas can be supplied. In the suction chamber 22 and the diffuser section 23 , the air, ammonia, heavy oil, and flue gas are mixed by the energy of the air flow blown into the suction chamber 22 from the nozzle section 21 . In this embodiment, as will be described later, the return path 5 is directly connected to the suction chamber 22, the return path 5 is connected to the ammonia supply unit 3 and the second fuel supply unit 4, and ammonia and heavy oil are returned. It is supplied to the suction chamber 22 via the channel 5 .

The return path 5 is a tubular piping member that supplies combustion exhaust gas to the fuel supply section 2 . One end of the return path 5, which is a suction port for sucking combustion exhaust gas, is arranged in the combustion vessel 9 and communicates with the furnace space S. The return path 5 is connected to the suction chamber 22 at the other end with respect to the suction port, and communicates with the space inside the suction chamber 22 . The suction port of the return path 5 may be arranged at a position adjacent to the tubular portion 10 on the downstream side of the tubular portion 10 , for example. Thereby, the combustion device 100 can be downsized.

As described above, since the suction chamber 22 has a negative pressure, the combustion exhaust gas can be sucked through the return path 5 from the combustion chamber 9 and supplied to the suction chamber 22 due to the pressure difference between the combustion chamber 9 and the combustion chamber 9 . Hereinafter, the combustion exhaust gas supplied to the combustion vessel 9 or the suction chamber 22 may be simply referred to as return gas. Further, the effect of the ejector mechanism in which the return path 5 is sucked by the negative pressure of the suction chamber 22 may be referred to as a suction effect. The return line 5 may be provided with a flow control valve 51 (so-called damper), such as a slide valve or a butterfly valve, which adjusts the opening degree of the valve to adjust the flow rate of the return gas. The return line 5 may have a temperature sensor 59 for measuring the temperature of the return gas upstream of the flow control valve 51 .

The ammonia supply unit 3 is a mechanism that supplies heated ammonia gas to the fuel supply unit 2 . The ammonia supply unit 3 includes a heat exchange unit 30 that heats the ammonia supplied from the ammonia supply system 6 by heat exchange within the combustion vessel 9, and supplies the ammonia heated by the heat exchange unit 30 to the fuel supply unit 2. Ammonia piping 31 is provided.

The heat exchange section 30 is a member having a heat exchanger and the like. The heat exchange section 30 may have, for example, a heat exchanger in which a metal tube through which ammonia can flow is coiled. The heat exchange section 30 is arranged, for example, downstream of the flow of flue gas generated in the combustion space forming section 1, and heat-exchanges with the flue gas, that is, takes in the heat of the flue gas to heat ammonia. The heat exchange section 30 may be arranged, for example, immediately downstream of the combustion space forming section 1 and directly exposed to the flames jetted into the furnace space S from the combustion space forming section 1 . By setting it as such arrangement|positioning, the heat exchange part 30 can heat ammonia efficiently. The heat exchange section 30 may be arranged at a position where it is not directly exposed to the flame that blows out from the combustion space forming section 1 into the furnace space S, and may exchange heat with the flue gas. In this way, the life of the heat exchange section 30 may be extended.

As described above, in this embodiment, the return line 5 is connected to the ammonia supply unit 3 , and ammonia is supplied to the fuel supply unit 2 via the return line 5 . In FIG. 1, as an example, the ammonia supply port 32 of the ammonia pipe 31 is connected between the suction chamber 22 and the flow control valve 51 in the return line 5, and ammonia is supplied from the ammonia pipe 31 to the return line 5. indicates the case. In addition, FIG. 1 illustrates a case where a temperature sensor 39 for measuring the temperature of ammonia is provided between the ammonia supply port 32 and the heat exchange section 30 in the ammonia pipe 31 .

The ammonia supply unit 3 heats the ammonia to a high temperature using the heat exchange unit 30, thereby facilitating combustion of ammonia in the combustion space forming unit 1 and enabling combustion of ammonia alone. In the heat exchange section 30, ammonia is heated from 400°C to 800°C. Ammonia is preferably heated to 500° C. or higher. When ammonia is heated to 500° C. or higher, the combustion stability of ammonia alone is improved.

In the heat exchange section 30, when ammonia is heated to a high temperature, some of the ammonia may be thermally decomposed to generate hydrogen. This hydrogen is supplied to the combustion space forming part 1 through the fuel supply part 2 together with ammonia, and is burned in the furnace space S. This hydrogen may improve combustion stability during combustion of ammonia alone.

Hydrogen generated by thermal decomposition of ammonia in the heat exchange unit 30 has a molar concentration of 0.5 in the mixed gas (mixed gas of ammonia and hydrogen generated by decomposition of ammonia) on the downstream side of the heat exchange unit 30. % or more and 20% or less. The molar concentration of hydrogen in the mixed gas is preferably 1% or more and 12% or less.

The second fuel supply section 4 is a mechanism that supplies heated heavy oil to the fuel supply section 2 . The second fuel supply unit 4 heats the heavy oil supplied from the second fuel supply system 7 with combustion exhaust gas and supplies the fuel oil to the fuel supply unit 2 .

As described above, in this embodiment, the return path 5 is connected to the second fuel supply section 4 , and heavy oil is supplied to the fuel supply section 2 via the return path 5 . In FIG. 1, as an example, a heavy oil supply port 41 as the second fuel supply unit 4 is connected between the suction chamber 22 and the ammonia supply port 32 in the return route 5, and the return route from the second fuel supply unit 4 5 is supplied with heavy oil.

By supplying the heavy oil to the return path 5, the second fuel supply unit 4 can heat the heavy oil by exchanging heat between the heavy oil and the return gas as combustion exhaust gas. When the heavy oil is heated, its viscosity is reduced, making it easier to atomize, and vaporizing it to improve its mixing with air or the like in the fuel supply section 2 . As a result, the supply of heavy oil to the combustion space forming portion 1 from the fuel supply portion 2 is stabilized, and the combustion of the heavy oil in the combustion space forming portion 1 is stabilized.

The operation of the combustion system 200 will be described below. The operation of the combustion system 200 is realized by the control of the controller C in this embodiment. In the following explanation, the operation of each part is assumed to be performed based on the operation command of the control unit C unless otherwise specified, and the explanation of the operation command of the control unit C will be omitted as appropriate.

In the combustion system 200 , when starting combustion in the combustion device 100 , first, the pilot burner 19 ignites the seed flame, and the supply of fuel and air from the fuel supply unit 2 is started. An igniter can be used to ignite the seed light in the pilot burner 19 . Heavy oil or combustible gas may be used as fuel for the seed light ignited by the pilot burner 19 . This embodiment shows a case where the pilot burner 19 uses heavy oil as fuel to burn pilot light. The fuel supply unit 2 preferably supplies only heavy oil as fuel to the combustion space forming unit 1 at the start of combustion in the combustion device 100 and immediately after the start of combustion.

In this embodiment, heavy oil is supplied from the second fuel supply system 7 to the second fuel supply section 4 based on the operation command of the control section C. That is, the controller C starts combustion in the combustion device 100 using heavy oil. The control unit C, for example, outputs the flow rate sensor 73 provided in the heavy oil supply pipe 71 connected to the second fuel tank 70 as a heavy oil tank of the second fuel supply system 7 and the second fuel supply unit 4 Based on the signal, the output of the pump 72 provided in the supply pipe 71 is adjusted to adjust the amount of heavy oil supplied from the second fuel tank 70 to the second fuel supply section 4 . As the pump 72, a turbine pump, a diaphragm pump, or the like can be used. The output of the pump 72 may be adjusted by adjusting the number of revolutions or the number of pistons. In the case of a turbine pump, a valve element may be provided on the downstream side, and the output may be adjusted by the degree of opening of the valve while the number of revolutions of the turbine is kept constant.

In this embodiment, air is supplied from the oxygen carrier gas supply system 8 to the oxygen carrier gas supply unit 20 based on the operation command of the control unit C. For example, the control unit C receives the output signal of a flow rate sensor 83 or a pressure sensor 84 provided in a blower pipe 81 connected to a blower 80 such as a fan or a blower of the oxygen carrier gas supply system 8 and the oxygen carrier gas supply unit 20. , the opening of the air volume control valve 82 provided in the blower pipe 81 or the output of the blower 80 is adjusted to adjust the amount of air supplied from the blower 80 to the oxygen carrier gas supply unit 20 . The air volume control valve 82 is, for example, an opening control valve (damper) such as a butterfly valve.

When the supply of air to the fuel supply unit 2 is started, the inside of the combustion vessel 9 is sucked through the return path 5 by the suction effect of the ejector mechanism of the fuel supply unit 2, and the return gas starts to be returned. In the combustion state of heavy oil alone, the flow rate of the return gas is preferably 0.05 or more and 1.0 or less, assuming that the flow rate of the air supplied to the fuel supply unit 2 is 1.

As the combustion by the combustion space forming part 1 continues, the temperature of the flue gas in the combustion vessel 9 gradually rises. As the temperature of the return gas rises as the temperature of the flue gas rises, the return gas heats the heavy oil in the return line 5 . When the temperature of the combustion exhaust gas reaches a predetermined value (e.g., 800° C. or higher), atomization and vaporization of the heavy oil in the fuel supply section 2 become favorable, and the combustion flame in the combustion space forming section 1 becomes stable. reach.

When the temperature of the combustion exhaust gas reaches a predetermined temperature or higher (e.g., 800 degrees or higher) after combustion starts in the combustion device 100, the control unit C causes the ammonia supply unit 3 to stop supplying ammonia to the fuel supply unit 2. Start. That is, when the temperature of the combustion exhaust gas reaches a predetermined temperature or higher, the control unit C starts combustion of ammonia in the combustion device 100 and switches the combustion device 100 to a mixed combustion state of ammonia and heavy oil. For example, the control unit C detects that the temperature of the combustion exhaust gas has reached a predetermined temperature or higher based on the output signal of the temperature sensor 99 provided in the combustion vessel 9 or the temperature sensor 59 provided in the return path 5, Supply of ammonia to the fuel supply unit 2 by the ammonia supply unit 3 can be started. Ammonia supplied to the fuel supply section 2 is supplied to the combustion space forming section 1 and combusted.

In this embodiment, ammonia is supplied from the ammonia supply system system 6 to the ammonia supply unit 3 based on the operation command of the control unit C. For example, the control unit C adjusts the flow rate provided in the ammonia supply pipe 61 based on the output signal of the flow sensor 63 provided in the ammonia supply pipe 61 connected to the ammonia cylinder 60 and the ammonia supply unit 3. The amount of ammonia supplied from the ammonia cylinder 60 to the ammonia supply unit 3 is adjusted by adjusting the opening degree of the valve 62 . The flow rate control valve 62 is an opening degree control valve such as a diaphragm valve or a needle valve, which can adjust the flow rate by adjusting the opening degree of the valve.

Based on the temperature of the flue gas or the temperature of the ammonia flowing through the ammonia pipe 31, the control unit C adjusts the supply amounts of air, heavy oil and ammonia to an appropriate ratio. The control unit C switches combustion in the combustion space forming unit 1 to combustion of ammonia alone, as required or based on an operator or a predetermined operation program.

For example, when the temperature of the flue gas reaches a predetermined temperature or higher after the combustion in the combustion device 100 has started, the control unit C starts supplying ammonia while continuing to supply heavy oil, thereby controlling the combustion device 100 as heavy oil and ammonia. Mixed combustion with After that, the amount of ammonia supplied is increased while the amount of heavy oil supplied is decreased, and the ratio of ammonia in the calorific value ratio is gradually increased. At this time, the control unit C monitors (maintains) the temperature of the combustion exhaust gas so that the temperature of the combustion exhaust gas does not drop below a predetermined temperature (for example, does not drop below 600° C.) using the temperature sensor 99 or the temperature sensor 59. Increase the proportion of ammonia. In addition, while monitoring (maintaining) the temperature of ammonia so that the temperature of ammonia does not fall below a predetermined temperature (for example, does not fall below 400 ° C.) by the temperature sensor 39, the ratio of ammonia in the calorific value ratio is increased, and ammonia alone to the combustion state of When the temperature sensor 99 or the temperature sensor 59 detects that the temperature of the combustion exhaust gas has decreased below a predetermined temperature, or when the temperature sensor 39 detects that the temperature of ammonia has decreased below a predetermined temperature. may stop increasing the proportion of ammonia in the heat ratio and temporarily reduce the proportion of ammonia in the heat ratio. As a result, the temperature of the combustion exhaust gas and the temperature of ammonia can be prevented from further decreasing, and the temperature can be recovered to a predetermined temperature or higher.

Even after the combustion device 100 shifts to the combustion state of ammonia alone, the control unit C continues to monitor the temperature of any one or more of the

temperature sensors

39, 59, 99 as necessary, and the fuel supply unit 2 You may adjust the amount of ammonia supplied, the amount of air supplied, or the amount of heavy oil supplied to. For example, when the temperature of the combustion exhaust gas drops extremely or the temperature of ammonia drops below a predetermined value, the supply of heavy oil may be started again to create a mixed combustion state of heavy oil and ammonia. Further, depending on the application of the combustion device 100 or the combustion system 200, the control unit C may continue the mixed combustion state of ammonia and heavy oil.

The controller C may adjust the amount of return gas supplied from the return path 5 as necessary. Through such adjustment control, the turndown ratio of the combustion device 100 can be increased. For example, in a combustion state of ammonia alone, the flow control valve 51 may be closed to stop the supply of return gas. By stopping the return gas supply, it is possible to increase the turndown ratio in the combustion state of ammonia alone.

In this embodiment, since the heavy oil supply port 41 and the ammonia supply port 32 are connected to the return path 5, when the supply of ammonia is started, the return amount of the return gas naturally decreases, The oxygen concentration of the mixed gas supplied to the combustion space forming section 1 is increased and automatically adjusted to a state suitable for ammonia combustion. The reason why the return amount of the return gas naturally decreases when the supply of ammonia is started is that the proportion of ammonia in the fluid sucked from the return passage 5 by the suction effect of the ejector mechanism of the fuel supply unit 2 is relatively low. , and the ratio of the return gas decreases accordingly. That is, by connecting the heavy oil supply port 41 and the ammonia supply port 32 to the return path 5, the turndown ratio of the combustion device 100, that is, the turndown ratio of the combustion system 200 can be increased.

(Modification 1 of the first embodiment)
In the first embodiment, the oxygen carrier gas is used to increase the turndown ratio of the combustion system 200, improve the combustion state in the combustion vessel 9, and reduce the oxygen concentration in the combustion exhaust gas. In addition to air as the oxygen carrier gas supplied to the supply unit 20, the combustion vessel 9 may supply secondary air as the second oxygen carrier gas to the furnace space S.

FIG. 2 shows the configuration of the combustion system 200 when the secondary air is supplied to the second combustion space S2, which is the space outside the first combustion space S1 in the combustion vessel 9, that is, the furnace space S. 2 shows an explanatory diagram.

In this modification, the combustion vessel 9 includes a secondary air supply port 95 for introducing secondary air into the combustion vessel 9, and a secondary air supply port 95 provided in the combustion vessel 9 and connected to the secondary air supply port 95. A supply container 96 is shown. The secondary air supply port 95 is formed, for example, as a through hole penetrating through the cylindrical wall portion 90 . The secondary air supply container 96 is supplied with secondary air from the secondary air supply port 95 .

The secondary air supply container 96 may have, for example, a tubular secondary air nozzle portion 97 that accommodates the tubular portion 10 of the combustion space forming portion 1 . The secondary air supply container 96 is an opening portion of the secondary air nozzle portion 97 positioned downstream of the combustion space forming portion 1 by the secondary air nozzle portion 97, and is connected to the cylindrical wall of the secondary air nozzle portion 97. Secondary air may be supplied into the combustion vessel 9 through a gap with the secondary air nozzle portion 97 . Secondary air may be supplied to the secondary air supply port 95 via, for example, a second blower pipe 85 branched from the blower pipe 81 . A flow rate sensor 86 and a second air volume adjustment valve 87 may be provided in the second blower pipe 85, and the control unit C adjusts the opening degree of the second air volume adjustment valve 87 based on the output signal of the flow sensor 86. to adjust the amount of secondary air supplied.

By enabling the supply of secondary air into the combustion vessel 9, it is possible to increase the turndown ratio of the combustion system 200, improve the combustion state in the combustion vessel 9, or increase the oxygen concentration in the combustion exhaust gas. It may be possible to reduce

Also, by enabling the supply of secondary air into the combustion vessel 9, it may be possible to reduce the amount of nitrogen oxides (NOx) generated within the combustion vessel 9. For example, when secondary air is not supplied into the combustion vessel 9, nitrogen oxides generated with combustion in the combustion vessel 9 may be 5000 ppm or more. On the other hand, when secondary air is supplied into the combustion vessel 9, if the ratio between the ammonia supplied to the combustion device 100 and the secondary air supplied to the combustion vessel 9 is appropriately adjusted, the combustion vessel In some cases, nitrogen oxides generated with combustion in 9 can be reduced to 100 ppm or less.

(Modification 2 of the first embodiment)
In the first embodiment, in order to increase the turndown ratio of the combustion system 200, improve the combustion state in the combustion vessel 9, and reduce the oxygen concentration in the combustion exhaust gas, the combustion vessel 9 is Ammonia may be supplied as a secondary fuel to the in-furnace space S in addition to the ammonia supplied to the oxygen carrier gas supply unit 20 .

FIG. 3 shows an explanatory diagram of a configuration in which ammonia can be additionally supplied into the furnace space S as a secondary fuel in the combustion system 200 of Modification 1 above. In Modification 2, the second supply pipe 64 branched from the supply pipe 61 is connected to the downstream side of the flow rate sensor 86 and the second air volume control valve 87 in the second blower pipe 85 . The combustion vessel 9 can supply ammonia into the furnace space S via the secondary air supply port 95 and the secondary air supply vessel 96 .

A flow sensor 66 and a second flow control valve 65 may be provided on the second supply pipe 64 . The controller C can adjust the opening degree of the second flow control valve 65 based on the output signal of the flow sensor 66 to adjust the amount of ammonia supplied to the secondary air supply container 96 . In addition, the second flow control valve 65 is, for example, an opening control valve such as a diaphragm valve or a needle valve.

By making it possible to supply ammonia as a secondary fuel into the combustion vessel 9, the turndown ratio of the combustion system 200 can be increased, the combustion state within the combustion vessel 9 can be improved, or the oxygen concentration in the flue gas can be improved. can be realized in some cases.

(Second embodiment)
In the above-described first embodiment, the case where the second fuel is heavy oil has been exemplified and explained. In the second embodiment, the second fuel is propane gas instead of heavy oil, and as shown in FIG. 4, the second fuel supply unit 4 and the second fuel supply system 7 are configured to supply propane gas. Further, the combustion apparatus 100 differs from the first embodiment in that it does not have the return path 5 (see FIG. 1, etc.) shown in the first embodiment, and the rest is the same. Below, it demonstrates centering around difference with 1st embodiment.

In this embodiment, the ammonia supply port 32 of the ammonia pipe 31 is directly connected to the suction chamber 22 , and ammonia is directly supplied from the ammonia supply section 3 to the suction chamber 22 .

Also, the gaseous fuel supply port 45 as the second fuel supply section 4 is connected to the suction chamber 22 , and the propane gas is directly supplied from the second fuel supply section 4 to the suction chamber 22 . Alternatively, the gaseous fuel supply port 45 may be connected to the oxygen carrier gas supply unit 20 so that the propane gas is supplied to the suction chamber 22 together with the air.

Propane gas is supplied from the second fuel supply system 7 to the second fuel supply unit 4 based on the operation command from the control unit C. For example, the control unit C controls the flow rate sensor 73 provided in the propane gas supply pipe 71 connected to the second fuel cylinder 79 as a propane gas cylinder of the second fuel supply system 7 and the second fuel supply unit 4. Based on the output signal, the valve opening degree of the flow control valve 74 provided in the supply pipe 71 is controlled to adjust the amount of propane gas supplied from the second fuel cylinder 79 to the second fuel supply unit 4. . The flow control valve 74 is an opening degree control valve such as a diaphragm valve or a needle valve.

The pilot burner 19 may use propane gas as fuel to burn pilot flames.

In this embodiment, a combustion state of propane gas alone, a mixed combustion state of propane gas and ammonia, and a combustion state of ammonia alone are possible.

Natural gas may be used as the second fuel instead of propane gas.

According to the combustion system 200 of the second embodiment, return gas is not supplied to the combustion space forming section 1, so it is easy to increase the turndown ratio of the combustion device 100.

The combustion apparatus 100 and the combustion system 200 including the combustion apparatus 100 described above are widely used, for example, as fuel for ships at present. Hydrocarbon gas such as propane gas and natural gas, which are low-carbon fuels that have the potential to be used in the future, and ammonia, which is expected to be a next-generation fuel that does not emit carbon dioxide, can be burned as fuel, especially for ships. Suitable for installed applications. The combustion device 100 and the combustion system 200 including the same are not only used as a general heat source such as a boiler, but also as an inert gas production device mounted on a ship, the amount of carbon dioxide generated is small and excellent. .

As described above, it is possible to provide a combustion device and a combustion system that increase the usage rate of ammonia as fuel.

[Another embodiment]
(1) In the above embodiment, when the temperature of the combustion exhaust gas reaches a predetermined temperature or higher after the combustion device 100 starts burning, the control unit C causes the ammonia supply unit 3 to supply ammonia to the fuel supply unit 2. Explained how to start. Further, the control unit C detects that the temperature of the combustion exhaust gas has reached a predetermined temperature or more based on the output signal of the temperature sensor 99 provided in the combustion vessel 9 or the temperature sensor 59 provided in the return line 5, for example. and the supply of ammonia to the fuel supply unit 2 by the ammonia supply unit 3 can be started.

However, instead of starting the supply of ammonia to the fuel supply unit 2 based on the temperature of the combustion exhaust gas, the control unit C supplies ammonia to the fuel supply unit 2 based on the state of the flame in the combustion space forming unit 1. It is also possible to adopt a mode in which the supply of is started. In this case, the combustion device 100 may include a flame sensor that detects the state of the flame in the combustion space forming section 1, and the supply of ammonia to the fuel supply section 2 is controlled based on the state of the flame detected by the flame sensor. you can start. As the flame sensor, a sensor that determines the state of the flame based on the light emitted by the flame (for example, ultraviolet light or visible light) or a sensor that determines the state of the flame based on the electrical conductivity of the flame may be used. That is, the control unit C can also cause the ammonia supply unit 3 to start supplying ammonia to the fuel supply unit 2 when the flame reaches a predetermined combustion state after combustion has started in the combustion device 100. .

(2) In the above embodiment, the control unit C monitors the temperature of one or more of the

temperature sensors

39, 59, and 99 as necessary even after the combustion device 100 transitions to the combustion state of ammonia alone. , and explained that the amount of ammonia supplied to the fuel supply unit 2, the amount of air supplied, or the amount of heavy oil supplied may be adjusted.
bottom.

However, instead of monitoring the temperature of one or more of the

temperature sensors

39, 59, and 99, the control unit C controls the amount of ammonia supplied to the fuel supply unit 2 based on the state of the flame in the combustion space forming unit 1. , the supply of air or the supply of heavy oil may be adjusted. In this case, the combustion device 100 may include a flame sensor that detects the state of the flame in the combustion space forming section 1, and the amount of ammonia supplied to the fuel supply section 2 based on the state of the flame detected by the flame sensor. , the supply of air or the supply of heavy oil may be adjusted. A frame sensor similar to that described above may be used.

It should be noted that the configurations disclosed in the above embodiments (including other embodiments, the same shall apply hereinafter) can be applied in combination with configurations disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in this specification are exemplifications, and the embodiments of the present disclosure are not limited thereto, and can be modified as appropriate without departing from the scope of the present disclosure.

The present disclosure is applicable to combustion devices and combustion systems.

Reference Signs List 1: Combustion space forming part 10: Cylindrical part 100: Combustion device 19: Pilot burner 2: Fuel supply part 20: Oxygen carrier gas supply part 200: Combustion system 21: Nozzle part 22: Suction chamber 23: Diffuser part 3: Ammonia Supply unit 30 : Heat exchange unit 31 : Ammonia pipe 32 : Ammonia supply port 39 : Temperature sensor 4 : Second fuel supply unit 41 : Heavy oil supply port 45 : Gaseous fuel supply port 5 : Return line 51 : Flow rate adjustment valve 59 : Temperature Sensor 6: Ammonia supply system 60: Ammonia cylinder 61: Supply pipe 62: Flow control valve 63: Flow sensor 64: Second supply pipe 65: Second flow control valve 66: Flow sensor 7: Second fuel supply system 70: Second Second fuel tank 71 : Supply pipe 72 : Fuel pump 73 : Flow rate sensor 74 : Flow rate adjustment valve 79 : Second fuel cylinder 8 : Oxygen carrier gas supply system 80 : Blower 81 : Blower tube 82 : Air volume adjustment valve 83 : Flow rate sensor 84 : Pressure sensor 85 : Second blower pipe (second oxygen carrier gas passage)
86 : Flow rate sensor 87 : Second air volume control valve 9 : Combustion vessel 90 : Cylindrical wall 91 : Bottom wall 95 : Secondary air supply port 96 : Secondary air supply container 97 : Secondary air nozzle 99 : Temperature sensor C : Control unit S : In-furnace space S1 : First combustion space S2 : Second combustion space

Claims

a combustion space forming part that forms a first combustion space for burning ammonia as a first fuel or a second fuel different from the ammonia as a fuel;
a fuel supply unit that supplies the fuel to the combustion space forming unit;
an ammonia supply unit that supplies the ammonia to the fuel supply unit;
a second fuel supply unit that supplies the second fuel to the fuel supply unit;
The ammonia supply unit is
Having a heat exchange unit that heats the ammonia,
A combustion device that supplies the ammonia heated in the heat exchange section to the fuel supply section.
the fuel supply is supplied with an oxygen carrier gas,
a mixing mechanism for mixing the ammonia or the second fuel and the oxygen carrier gas to form a mixed gas;
2. The combustion apparatus according to claim 1, wherein said mixed gas is supplied to said combustion space forming portion.
3. The mixing mechanism according to claim 2, wherein the mixing mechanism is an ejector mechanism that mixes the oxygen carrier gas and the second fuel or the ammonia by the energy of the airflow of the oxygen carrier gas and feeds the mixed gas into the combustion space forming portion. combustion device.
The ejector mechanism is
a suction chamber to which the ammonia is supplied from the ammonia supply unit;
a nozzle section for blowing the oxygen carrier gas into the suction chamber;
4. The combustion apparatus according to claim 3, further comprising a diffuser section connected in communication with the downstream side of the suction chamber.
further comprising a return passage for supplying combustion exhaust gas generated in the combustion space forming portion to the fuel supply portion;
5. The combustion apparatus according to claim 4, wherein said return path is connected to said suction chamber.
The combustion apparatus according to claim 5, wherein the second fuel supply section supplies the second fuel to the fuel supply section through the return path.
The combustion apparatus according to claim 5 or 6, wherein the ammonia supply section supplies the ammonia to the fuel supply section through the return path.
The combustion apparatus according to any one of claims 5 to 7, wherein the return path has a flow control valve for adjusting the flow rate of the combustion exhaust gas.
The combustion apparatus according to any one of claims 4 to 8, wherein the second fuel supply section supplies the second fuel together with the oxygen carrier gas to the suction chamber through the nozzle section.
The combustion apparatus according to any one of claims 2 to 9, further comprising an oxygen carrier gas supply section for supplying the oxygen carrier gas to the fuel supply section.
11. The heat exchange section according to any one of claims 1 to 10, wherein the heat exchange section is arranged downstream of the flow of combustion exhaust gas generated in the combustion space forming section, and performs heat exchange between the combustion exhaust gas and the ammonia. Combustion device.
A combustion device according to any one of claims 1 to 11;
A combustion vessel in which the combustion device is mounted and which forms a furnace space,
The combustion system, wherein the combustion vessel accommodates the combustion space forming part in the furnace space.
13. The combustion system of claim 12, wherein the combustion vessel is within the furnace space and supplies a second oxygen carrier gas to a space outside the first combustion space.
14. The combustion system according to claim 12 or 13, wherein the combustion vessel supplies ammonia as a second fuel to a space outside the first combustion space inside the furnace space.
further comprising a control unit,
The control unit controls the amount of ammonia supplied to the fuel supply unit based on the temperature of the combustion exhaust gas generated in the combustion vessel, the temperature of the ammonia heated in the heat exchange unit, or the state of the flame. 15. The combustion system according to any one of claims 12 to 14, wherein the ratio of the second fuel supply to the fuel supply unit is adjusted.
The control unit
starting the combustion device with the second fuel;
When the temperature of the combustion exhaust gas reaches a predetermined temperature or higher, the combustion device is switched to a mixed combustion state of the ammonia and the second fuel, and then to a combustion state of the ammonia alone,
When switching from the mixed combustion state to the combustion state of the ammonia alone, the ratio of the ammonia in the mixed combustion state is increased while maintaining the temperature of the ammonia heated in the heat exchange unit at a predetermined value or higher. 16. The combustion system according to claim 15, wherein the combustion state is shifted to a combustion state in which only the ammonia is used.