Fuel preheater

Abstract

A fuel preheater (10) includes: a first mixer (1) which is provided to a fuel supply line (L1) connected to combustion facilities (100) for burning a fuel including ammonia, the fuel supply line (L1) supplying ammonia to the first mixer (1), the first mixer (1) being connected to an oxidizing-agent supply line (L2) for oxidizing-agent supply and mixing the ammonia flowing through the fuel supply line (L1) with the oxidizing agent from the oxidizing-agent supply line (L2), thereby forming a mixture gas; and a reactor (2) provided downstream from the first mixer (1) in the fuel supply line (L1) and containing a catalyst which accelerates an ammonia reaction to cause an exothermic reaction, the catalyst causing the exothermic reaction due to at least some of the ammonia contained in the mixture gas supplied from the first mixer (1), thereby heating the mixture gas.

Description

Technical Field

[0001] This disclosure relates to a fuel preheater. This application claims the benefit of priority based on Japanese Patent Application No. 2023-097818 filed on June 14, 2023, the content of which is incorporated herein by reference.

Background Art

[0002] In combustion equipment, a catalyst may be used to promote combustion. For example, Patent Document 1 discloses a catalytic flameless combustion device. In this device, a mixed gas of air and natural gas is combusted on a catalyst filled in a combustion chamber.

[0003] Further, Patent Document 2 discloses a catalytic combustion burner. In this burner, a mixed gas of gaseous fuel such as natural gas or city gas and air is combusted on a catalyst.

[0004] Further, Patent Document 3 discloses a burner portion of a gas turbine. In this gas turbine, a mixed gas of natural gas and air is oxidized by a catalyst and further combusted with a pilot flame and a main flame.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] Ammonia is known as a fuel that does not emit CO2. However, its combustion rate is slower than that of other fuels such as natural gas. Therefore, when using ammonia in combustion equipment, it is desirable to increase the combustion rate of ammonia.

[0007] This disclosure aims to provide a fuel preheater that can supply fuel to a combustion facility while increasing the combustion rate when ammonia is used as fuel in the combustion facility. Furthermore, this disclosure aims to provide a method for installing such a fuel preheater in a combustion facility. [Means for solving the problem]

[0008] A fuel preheater according to one aspect of the present disclosure is a first mixer provided in a fuel supply line connected to a combustion facility that burns a fuel containing ammonia, the fuel supply line supplies ammonia to the first mixer, the first mixer is connected to an oxidizer supply line that supplies an oxidizer, and the first mixer mixes ammonia flowing through the fuel supply line with an oxidizer from the oxidizer supply line to produce a mixed gas; and a reactor provided downstream of the first mixer in the fuel supply line, the reactor includes a catalyst that promotes the reaction of ammonia and causes an exothermic reaction, the catalyst causes an exothermic reaction by at least a portion of the ammonia in the mixed gas supplied from the first mixer, and heats the mixed gas. A first valve provided in the oxidizer supply line for adjusting the flow rate of the oxidizer supplied to the first mixer, and a control device connected to the first valve in a manner that enables communication with the first valve, Includes Furthermore, the control device is configured to control the first valve to continue supplying the oxidizer to the reactor while supplying fuel containing ammonia to the combustion equipment. .

[0009] The fuel preheater may include a second mixer located downstream of the reactor in the fuel supply line, the second mixer being connected to the oxidizer supply line by a first bypass line, and mixing the mixed gas supplied from the reactor with the oxidizer supplied from the first bypass line.

[0010] The fuel preheater is , burn A temperature sensor installed downstream of the reactor in the feed supply line to measure the temperature of the mixed gas. The control device may also be equipped with, The temperature sensor is connected in a way that allows it to communicate. But it's fine, The control device stores a predetermined threshold value associated with the temperature at which the material forming the fuel supply line begins to nitride. It is fine to do so, Your device controls the first valve to adjust the flow rate of the oxidizer supplied to the first mixer so that the temperature of the mixed gas, as measured by the temperature sensor, falls below a threshold. You may .

[0011] The reactor may include heating means for heating the catalyst, and the heating means may include a heater.

[0012] Alternatively or additionally, the heating means may include a first heat exchanger that heats the catalyst with exhaust gas from the combustion equipment.

[0013] Alternatively or additionally, the heating means may include a second heat exchanger that heats the catalyst with steam extracted from the combustion equipment.

[0014] The fuel preheater is a third mixer located downstream of the reactor in the fuel supply line, and the third mixer may be connected by a second bypass line to a position upstream of the first mixer in the fuel supply line, and mix the mixed gas supplied from the reactor with ammonia supplied from the second bypass line.

[0015] The fuel preheater is located upstream of the first mixer in the fuel supply line and includes a second valve that adjusts the flow rate of ammonia supplied to the first mixer, and a temperature sensor located downstream of the reactor in the fuel supply line that measures the temperature of the mixed gas. The control device may also be equipped with, The second valve and temperature sensor are connected in a communicative manner. But it's fine, The control device stores a predetermined threshold value associated with the temperature at which the material forming the fuel supply line begins to nitride. It is fine to do so, Your device controls the second valve to adjust the flow rate of ammonia supplied to the first mixer so that the temperature of the mixed gas, as measured by the temperature sensor, falls below a threshold. You may .

[0016] The fuel preheater may supply the mixed gas to a plurality of burners of the combustion equipment.

[0017] The exothermic reaction in the catalyst of the reactor may be catalytic combustion.

Advantages of the Invention

[0019] According to the present disclosure, when ammonia is used as a fuel in combustion equipment, the fuel can be supplied to the combustion equipment in a state where the combustion rate is increased.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a schematic view of combustion equipment including a fuel preheater according to the first embodiment. [Figure 2] FIG. 2 is a schematic view of combustion equipment including a fuel preheater according to the second embodiment. [Figure 3] FIG. 3 is a schematic view of combustion equipment including a fuel preheater according to the third embodiment.

Modes for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating understanding and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present disclosure are not shown.

[0022] Figure 1 is a schematic diagram of a combustion equipment 100 equipped with a fuel preheater 10 according to the first embodiment. The fuel preheater 10 is installed in a fuel supply line L1 connected to the combustion equipment 100. A gas containing ammonia flows through the fuel supply line L1. For example, the combustion equipment 100 can be a boiler, an industrial furnace, or a combustion furnace. The combustion equipment 100 is not limited to these and can be various types of equipment that use ammonia as fuel. The combustion equipment 100 may also be existing equipment. In other embodiments, the combustion equipment 100 may be newly installed equipment. For example, the combustion equipment 100 includes one or more burners B.

[0023] Burner B burns a fuel containing ammonia. For example, burner B may burn a mixture of ammonia and other fuels such as pulverized coal. Alternatively, burner B may burn only ammonia. Furthermore, burner B may burn a fuel that does not contain ammonia, if necessary.

[0024] For example, the fuel preheater 10 includes a first mixer 1, a reactor 2, a second mixer 3, and a control device 90. The fuel preheater 10 may further include other components not shown.

[0025] The first mixer 1 is installed in the fuel supply line L1. For example, the first mixer 1 may be installed in an existing fuel supply line L1 connected to an existing combustion equipment 100. For example, the first mixer 1 is a gas mixer. The fuel supply line L1 supplies ammonia to the first mixer 1. For example, the fuel supply line L1 supplies gaseous ammonia to the first mixer 1.

[0026] An oxidizing agent supply line L2 is connected to the first mixer 1. The oxidizing agent supply line L2 supplies an oxidizing agent (for example, air) to the first mixer 1.

[0027] A valve (first valve) V1 is provided in the oxidizer supply line L2. Valve V1 is connected to a control device 90 via wired or wireless communication and is controlled by the control device 90. The control device 90 adjusts the flow rate of the oxidizer supplied to the first mixer 1 by controlling the opening degree of valve V1.

[0028] The first mixer 1 mixes ammonia flowing through the fuel supply line L1 with an oxidizer supplied from the oxidizer supply line L2 to produce a mixed gas containing ammonia and oxidizer. The mixed gas flows through the fuel supply line L1 and is supplied to the reactor 2.

[0029] A nitrogen supply line L3 is connected to the first mixer 1. The nitrogen supply line L3 supplies nitrogen to the first mixer 1.

[0030] A valve V2 is provided in the nitrogen supply line L3. Valve V2 is connected to a control device 90 via wired or wireless communication and is controlled by the control device 90. The control device 90 adjusts the flow rate of nitrogen supplied to the first mixer 1 by controlling the opening degree of valve V2.

[0031] Reactor 2 is located downstream of the first mixer 1 in the fuel supply line L1. Similar to the first mixer 1, reactor 2 may be installed in relation to an existing fuel supply line L1 connected to an existing combustion facility 100. Reactor 2 receives the mixed gas from the first mixer 1. Reactor 2 includes a catalyst that promotes the reaction of ammonia to cause an exothermic reaction. Specifically, the catalyst promotes the reaction of at least some of the ammonia in the mixed gas supplied from the first mixer 1, causing catalytic combustion. The mixed gas is heated by catalytic combustion. The heated mixed gas flows through the fuel supply line L1 and is supplied to the second mixer 3.

[0032] For example, the catalyst contains transition elements (which may also be called transition metals). For example, the catalyst may contain noble metals such as Ru. Alternatively, for example, the catalyst may contain non-noble metals among the transition elements, such as Fe, Co, and Ni. Non-noble metals may exhibit high activity when combined with certain supports. As the support, for example, oxides such as Al2O3 or SiO2 may be used. Also, if necessary, a support that can suppress sintering, such as CeO2, may be used.

[0033] A temperature sensor S1 is provided in reactor 2. The temperature sensor S1 is configured to measure the temperature of the catalyst. The temperature sensor S1 is connected to the control device 90 via wired or wireless communication and transmits the measurement data to the control device 90.

[0034] The reactor 2 is provided with a heating means H. The heating means H heats the catalyst. For example, the heating means H may include an electric heater. Alternatively or additionally, the heating means H may include a first heat exchanger that heats the catalyst with exhaust gas from the combustion equipment 100. Further alternatively or additionally, if the combustion equipment 100 includes a boiler, the heating means H may include a second heat exchanger that heats the catalyst with steam extracted from the combustion equipment 100. The heating means H is communicated with and controlled by a control device 90 via wired or wireless means.

[0035] For example, when the fuel preheater 10 starts operation, the control device 90 starts the operation of the heating means H and heats the catalyst until the temperature measured by the temperature sensor S1 reaches the temperature at which the catalyst begins to activate (e.g., 400°C). When the temperature measured by the temperature sensor S1 reaches the temperature at which the catalyst begins to activate, the control device 90 stops the operation of the heating means H. From this point onward, the catalyst is maintained at a sufficient temperature by catalytic combustion.

[0036] The second mixer 3 is located downstream of the reactor 2 in the fuel supply line L1. Similar to the first mixer 1 and reactor 2, the second mixer 3 may be installed in relation to an existing fuel supply line L1 connected to an existing combustion facility 100. For example, the second mixer 3 is a gas mixer. The second mixer 3 receives a heated mixed gas from the reactor 2.

[0037] The second mixer 3 is connected to the oxidant supply line L2 by a bypass line (first bypass line) BL1. Bypass line BL1 directly connects the oxidant supply line L2 to the second mixer 3 without passing through the first mixer 1 and reactor 2. Therefore, at least a portion of the oxidant flowing through the oxidant supply line L2 is supplied to the first mixer 1, and the remainder of the oxidant is supplied to the second mixer 3.

[0038] A valve V3 is provided in the bypass line BL1. Valve V3 is connected to the control device 90 via wired or wireless communication and is controlled by the control device 90. The control device 90 adjusts the flow rate of the oxidizer supplied to the second mixer 3 by controlling the opening degree of valve V3.

[0039] The second mixer 3 further mixes the mixed gas flowing through the fuel supply line L1 with the oxidizer supplied from the bypass line BL1. The mixed gas flows through the fuel supply line L1 and is supplied to the burner B as fuel (premixed combustion method). In other embodiments, the burner B may be a diffusion combustion method.

[0040] A temperature sensor S2 is provided in the fuel supply line L1 downstream of the reactor 2, specifically downstream of the second mixer 3 in this embodiment. The temperature sensor S2 is configured to measure the temperature of the mixed gas flowing through the fuel supply line L1. The temperature sensor S2 is connected to the control device 90 via wired or wireless communication and transmits the measurement data to the control device 90.

[0041] The fuel supply line L1 branches into multiple lines downstream of the temperature sensor S2, and each of these lines is connected to a separate burner B.

[0042] The control device 90 controls the fuel preheater 10. The control device 90 may also control at least some of the components of the combustion equipment 100. For example, the combustion equipment 100 may include a main control device (not shown), and the control device 90 may communicate with the main control device. The control device 90 includes components such as a processor 90a, a storage device 90b, and a connector 90c, which are connected to each other via a bus. For example, the processor 90a includes a CPU (Central Processing Unit), etc. For example, the storage device 90b This includes a hard disk, a ROM for storing programs, and RAM as a work area. The control device 90 is connected to each component of the fuel preheater 10 via a connector 90c so as to be able to communicate with it by wire or wirelessly. For example, the control device 90 may further include other components such as a display device such as a liquid crystal display or a touch panel, and an input device such as a keyboard, buttons, or a touch panel. For example, the operation of the control device 90 may be realized by having the processor 90a execute a program stored in the storage device 90b.

[0043] The catalyst in reactor 2 accelerates the reaction of ammonia, causing the following reactions (1), (2), or a combination thereof. (1)NH3→1.5H2+0.5N2ΔH=45.4(kJ / mol) (2)2NH3+1.5O2→N2+3H2O ΔH=-382.6(kJ / mol)

[0044] For example, in this embodiment, the catalyst can cause both reactions (1) and (2). For example, the control device 90 may control valve V1 to adjust the amount of oxidant allocated from the oxidant supply line L2 to the first mixer 1, i.e., the amount of oxidant supplied to the reactor 2, so that most of the oxidant in the mixed gas supplied to the reactor 2 is used by reaction (2), which is an exothermic reaction. The control device 90 may also control valve V3 as needed.

[0045] For example, if reactor 2 requires more oxidant for catalytic combustion, the control device 90 increases the flow rate of oxidant supplied to reactor 2 from the oxidant supply line L2. Conversely, if, for example, the amount of oxidant supplied to reactor 2 is excessive, the control device 90 reduces the flow rate of oxidant supplied to reactor 2 from the oxidant supply line L2.

[0046] The oxidizer required for combustion in burner B is supplied from the oxidizer supply line L2 to the second mixer 3 via the bypass line BL1, where it is mixed with the heated mixed gas. The control device 90 controls valve V3 to adjust the amount of oxidizer allocated from the oxidizer supply line L2 to the bypass line BL1, i.e., the amount of oxidizer supplied to the second mixer 3. The control device 90 may also control valve V1 as needed.

[0047] For example, if burner B requires more oxidant for combustion, the control device 90 may increase the flow rate of oxidant supplied from the oxidant supply line L2 to the second mixer 3. Conversely, if, for example, the amount of oxidant supplied to burner B is excessive, the control device 90 may decrease the flow rate of oxidant supplied from the oxidant supply line L2 to the second mixer 3.

[0048] Furthermore, the control device 90 stores a predetermined threshold in the storage device 90b. This threshold is associated with the temperature at which the material forming the fuel supply line L1 begins to undergo nitriding. For example, the fuel supply line L1 may be formed of steel such as stainless steel. Many types of steel are known to undergo nitriding when exposed to an ammonia-containing environment at approximately 400°C to 600°C. Therefore, many types of steel will not undergo nitriding even when exposed to an ammonia-containing environment at temperatures below the above range. Specifically, for example, the threshold may be 400°C.

[0049] Furthermore, the threshold may be determined by testing. For example, a test specimen made of the same material as the material forming the fuel supply line L1 is placed in an environment simulating the inside of the fuel supply line L1. The environment is maintained for a predetermined period (e.g., one month, several months, one year, or several years). Then, the nitrided layer depth of the test specimen is measured, and the nitriding rate per year (mm / year) is calculated. This test is performed at multiple temperatures. For example, the temperature at which the nitriding rate is below a predetermined value may be determined as the threshold (e.g., less than 1 mm / year). For example, the nitrided layer depth may be measured by the "measurement method by hardness test" or the "measurement method by metallographic test" of the "Method for measuring nitrided layer depth of steel" specified in JIS G0562.

[0050] The control device 90 may adjust the flow rate of the oxidizer supplied to the reactor 2 and the flow rate of the oxidizer supplied to the second mixer 3 by controlling at least one of valves V1 and V3 so that the temperature of the mixed gas measured by the temperature sensor S2 is below a threshold.

[0051] Furthermore, if the temperature of the mixed gas measured by the temperature sensor S2 is excessively high, that is, if the catalyst is excessively heated by the exothermic reaction, the control device 90 may open the valve V2 and add nitrogen to the mixed gas as an emergency coolant.

[0052] Furthermore, the fuel supply line L1 may be provided with a valve (not shown) for adjusting the flow rate of ammonia supplied to the first mixer 1. Also, each of lines L1, L2, and L3 may be provided with a pump (not shown) for transporting fluid. These valves and pumps may be connected to the control device 90 via wired or wireless communication and may be controlled by the control device 90.

[0053] Next, we will explain the operation of the fuel preheater 10.

[0054] When the fuel preheater 10 starts operation, the control device 90 starts the operation of the heating means H. The catalyst is heated until the temperature measured by the temperature sensor S1 reaches the temperature at which the catalyst begins to activate.

[0055] When the temperature measured by the temperature sensor reaches the temperature at which the catalyst begins to activate, the control device 90 controls the valve V1 and starts supplying the oxidizer to the first mixer 1. The first mixer 1 also receives ammonia from the fuel supply line L1. The first mixer 1 mixes the ammonia and the oxidizer to produce a mixed gas. The mixed gas is supplied to the reactor 2 via the fuel supply line L1.

[0056] Furthermore, the control device 90 stops the operation of the heating means H. From this point onward, the catalyst is maintained at a sufficient temperature by catalytic combustion.

[0057] At least some of the oxidizing agent in the gas mixture, for example, most of the oxidizing agent in the gas mixture, reacts with ammonia on the catalyst in reactor 2, causing catalytic combustion. This heats the gas mixture. The heated gas mixture is supplied to the second mixer 3 by the fuel supply line L1.

[0058] The control device 90 controls valve V3 and starts supplying the oxidizer necessary for combustion in burner B to the second mixer 3. The second mixer 3 also receives heated mixed gas from fuel supply line L1. The second mixer 3 further mixes the ammonia and oxidizer. The heated mixed gas is supplied as premixed fuel to multiple burners B via fuel supply line L1.

[0059] The fuel preheater 10 described above comprises a first mixer 1 located in a fuel supply line L1 connected to a combustion equipment 100 that burns a fuel containing ammonia, and a reactor 2 located downstream of the first mixer 1 in the fuel supply line L1. The fuel supply line L1 supplies ammonia to the first mixer 1. The first mixer 1 is connected to an oxidizer supply line L2 that supplies an oxidizer, and mixes the ammonia flowing through the fuel supply line L1 with the oxidizer from the oxidizer supply line L2 to produce a mixed gas. The reactor 2 contains a catalyst that promotes the reaction of ammonia and causes an exothermic reaction. The catalyst causes an exothermic reaction by at least a portion of the ammonia in the mixed gas supplied from the first mixer 1, heating the mixed gas. With this configuration, a mixed gas containing ammonia and heated by the exothermic reaction in the reactor 2 can be supplied to the combustion equipment 100. Because the mixed gas is heated by the exothermic reaction, the ammonia in the mixed gas is also heated, and the combustion rate of ammonia is increased. Therefore, fuel can be supplied to the combustion equipment 100 with an increased combustion rate.

[0060] Furthermore, the fuel preheater 10 includes a second mixer 3 located downstream of the reactor 2 in the fuel supply line L1. The second mixer 3 is connected to the oxidizer supply line L2 by a bypass line BL1 and mixes the mixed gas supplied from the reactor 2 with the oxidizer supplied from the bypass line BL1. With this configuration, the amount of oxidizer supplied from the oxidizer supply line L2 to the reactor 2 can be adjusted more precisely.

[0061] Furthermore, the fuel preheater 10 includes a valve V1 provided in the oxidizer supply line L2 for adjusting the flow rate of the oxidizer, a temperature sensor S2 provided downstream of the reactor 2 in the fuel supply line L1 for measuring the temperature of the mixed gas, and a control device 90 that is communicatively connected to the valve V1 and the temperature sensor S2. The control device 90 stores a predetermined threshold value associated with the temperature at which the material forming the fuel supply line L1 begins to undergo nitriding. The control device 90 controls the valve V1 to adjust the flow rate of the oxidizer supplied to the first mixer 1 so that the temperature of the mixed gas measured by the temperature sensor S2 is below the threshold value. With this configuration, embrittlement of the fuel supply line L1 due to nitriding can be suppressed.

[0062] Furthermore, reactor 2 includes a heating means H for heating the catalyst, and the heating means H may include a heater. With this configuration, the catalyst can be quickly heated to the temperature at which it begins to become active.

[0063] Alternatively or additionally, the heating means H may include a first heat exchanger that heats the catalyst with exhaust gas from the combustion equipment 100. With such a configuration, the catalyst can be quickly heated to a temperature at which it begins to activate, and the exhaust gas can be reused.

[0064] Alternatively or additionally, the heating means H may include a second heat exchanger that heats the catalyst with steam extracted from the combustion equipment 100. With such a configuration, the catalyst can be quickly heated to a temperature at which it begins to activate.

[0065] Furthermore, the fuel preheater 10 supplies the mixed gas to multiple burners B of the combustion equipment 100. With this configuration, there is no need to provide a fuel preheater for each burner B.

[0066] Furthermore, the exothermic reaction in the catalyst of reactor 2 is catalytic combustion. With this configuration, reactor 2 operates primarily as a surface reaction without flame, thus ensuring high safety. In addition, by changing the flow rate of the oxidizer, the air ratio in reactor 2 can be changed, and the temperature of the mixed gas can be controlled. Increasing the temperature of the mixed gas can improve the ignition and combustion stability of the flame-retardant ammonia in burner B.

[0067] Furthermore, the fuel preheater 10 described above can be installed on an existing combustion equipment 100. The method for installing the fuel preheater 10 on the combustion equipment 100 according to this embodiment includes preparing a first mixer 1 configured to mix ammonia and an oxidizer, preparing a reactor 2 containing a catalyst that causes an exothermic reaction by ammonia, and installing the first mixer 1 on a fuel supply line L1 connected to a combustion equipment 100 that burns ammonia-containing fuel. As a result, the fuel supply line L1 supplies ammonia to the first mixer 1. The method according to this embodiment also includes connecting an oxidizer supply line L2 that supplies an oxidizer to the first mixer 1. As a result, the first mixer 1 mixes the ammonia flowing through the fuel supply line L1 with the oxidizer from the oxidizer supply line L2 to produce a mixed gas. The method according to this embodiment also includes installing the reactor 2 downstream of the first mixer 1 on the fuel supply line L1. As a result, the catalyst causes an exothermic reaction by at least a portion of the ammonia in the mixed gas supplied from the first mixer 1, heating the mixed gas. With this configuration, fuel can be supplied to the existing combustion equipment 100 at an increased combustion rate without requiring major construction work.

[0068] In Figure 1 and the following Figures 2 and 3, the fuel preheaters 10, 10A, and 10B include components enclosed by dashed lines. Therefore, the method of installing the fuel preheaters 10, 10A, or 10B to the combustion equipment 100 according to this disclosure may further include installing components other than the first mixer 1 and reactor 2 within the dashed lines relative to the existing fuel supply line L1.

[0069] Next, other embodiments will be described.

[0070] Figure 2 is a schematic diagram of a combustion system 100 equipped with a fuel preheater 10A according to the second embodiment. The fuel preheater 10A differs from the fuel preheater 10 according to the first embodiment in that it is equipped with an ammonia bypass line (second bypass line) BL2 and a third mixer 4 instead of an oxidizer bypass line BL1 and a second mixer 3. The other configurations of the fuel preheater 10A may be the same as those of the fuel preheater 10.

[0071] The third mixer 4 is located downstream of the reactor 2 in the fuel supply line L1. The third mixer 4 may be installed in relation to an existing fuel supply line L1 connected to an existing combustion facility 100. For example, the third mixer 4 is a gas mixer. The third mixer 4 receives a heated mixed gas from the reactor 2.

[0072] The third mixer 4 is connected to the fuel supply line L1 upstream of the first mixer 1 by a bypass line BL2. The bypass line BL2 directly connects the fuel supply line L1 to the third mixer 4 without passing through the first mixer 1 and reactor 2. Therefore, at least a portion of the ammonia flowing through the fuel supply line L1 is supplied to the first mixer 1, and the remainder of the ammonia is supplied to the third mixer 4.

[0073] In this embodiment, a valve (second valve) V4 is provided in the fuel supply line L1 between the connection point to the bypass line BL2 and the first mixer 1. The valve V4 is connected to the control device 90 via wired or wireless communication and is controlled by the control device 90. The control device 90 adjusts the flow rate of ammonia supplied to the first mixer 1 by controlling the opening degree of the valve V4.

[0074] A valve V5 is provided in the bypass line BL2. Valve V5 is connected to the control device 90 via wired or wireless communication and is controlled by the control device 90. The control device 90 adjusts the flow rate of ammonia supplied to the third mixer 4 by controlling the opening degree of valve V5.

[0075] The third mixer 4 further mixes the mixed gas flowing through the fuel supply line L1 with ammonia supplied from the bypass line BL2. The mixed gas flows through the fuel supply line L1 and is supplied to the burner B as fuel.

[0076] For example, the control device 90 may control valve V4 to adjust the flow rate of ammonia allocated from the fuel supply line L1 to the first mixer 1, i.e., the flow rate of ammonia supplied to the reactor 2, so that most of the ammonia in the mixed gas supplied to the reactor 2 is used by reaction (2), which is an exothermic reaction. The control device 90 may also control valve V5 as needed.

[0077] For example, if reactor 2 needs to heat the mixed gas more, the control device 90 may increase the flow rate of ammonia supplied from fuel supply line L1 to reactor 2. Conversely, if reactor 2 is overheating the mixed gas, for example, the control device 90 may decrease the flow rate of oxidizer supplied from fuel supply line L1 to reactor 2.

[0078] The ammonia required for combustion in burner B is supplied from fuel supply line L1 to third mixer 4 via bypass line BL2, where it is mixed with the heated mixed gas. The control device 90 controls valve V5 to adjust the amount of ammonia allocated from fuel supply line L1 to bypass line BL2, i.e., the amount of ammonia supplied to third mixer 4. The control device 90 may also control valve V4 as needed.

[0079] For example, if burner B requires more ammonia for combustion, the control device 90 may increase the flow rate of ammonia supplied from fuel supply line L1 to third mixer 4. Conversely, if, for example, the amount of ammonia supplied to burner B is excessive, the control device 90 may decrease the flow rate of ammonia supplied from fuel supply line L1 to third mixer 4.

[0080] Furthermore, similar to the first embodiment, the control device 90 may control at least one of valves V4 and V5 so that the temperature of the mixed gas measured by the temperature sensor S2 is below a threshold (e.g., 400°C), thereby adjusting the flow rate of ammonia supplied to the reactor 2 and the flow rate of ammonia supplied to the third mixer 4.

[0081] The fuel preheater 10A described above provides generally the same effects as the fuel preheater 10 according to the first embodiment. The fuel preheater 10A also includes a third mixer 4 located downstream of the reactor 2 in the fuel supply line L1. The third mixer 4 is connected to the fuel supply line L1 at a position upstream of the first mixer 1 by a bypass line BL2, and mixes the mixed gas supplied from the reactor 2 with ammonia supplied from the bypass line BL2. With this configuration, the amount of ammonia supplied from the fuel supply line L1 to the reactor 2 can be adjusted more precisely.

[0082] Furthermore, the fuel preheater 10A is provided upstream of the first mixer 1 in the fuel supply line L1 and includes a valve V4 that adjusts the flow rate of ammonia supplied to the first mixer 1, a temperature sensor S2 provided downstream of the reactor 2 in the fuel supply line L1 and measures the temperature of the mixed gas, and a control device 90 that is communicatively connected to the valve V4 and the temperature sensor S2. The control device 90 stores a predetermined threshold value associated with the temperature at which the material forming the fuel supply line L1 begins nitriding. The control device 90 controls the valve V4 to adjust the flow rate of ammonia supplied to the first mixer 1 so that the temperature of the mixed gas measured by the temperature sensor S2 is below the threshold value. With this configuration, embrittlement of the fuel supply line L1 due to nitriding can be suppressed.

[0083] Figure 3 is a schematic diagram of a combustion system 100 equipped with a fuel preheater 10B according to the third embodiment. The fuel preheater 10B differs from the fuel preheater 10 according to the first embodiment in that it does not have a bypass line BL1 and a second mixer 3. The other configurations of the fuel preheater 10B may be the same as those of the fuel preheater 10.

[0084] In this embodiment, each burner B of the combustion equipment 100 uses a diffusion combustion method. Each burner B is supplied with the air necessary for diffusion combustion. The combustion equipment 100 may include components not shown, such as air registers and dampers, for adjusting the amount of air supplied to each burner B. Note that in Figure 3, air is shown only for the uppermost burner B.

[0085] For example, the control device 90 controls valve V1 to adjust the amount of oxidant supplied from the oxidant supply line L2 to the reactor 2 via the first mixer 1, so that most of the oxidant in the mixed gas supplied to the reactor 2 is used by reaction (2), which is an exothermic reaction.

[0086] Furthermore, similar to the first embodiment, the control device 90 controls the valve V1 so that the temperature of the mixed gas measured by the temperature sensor S2 is below a threshold (for example, 400°C), thereby adjusting the flow rate of the oxidizer supplied to the reactor 2.

[0087] The fuel preheater 10B described above provides generally the same effects as the fuel preheater 10 according to the first embodiment.

[0088] Although embodiments have been described above with reference to the attached drawings, this disclosure is not limited to the embodiments described above. It will be 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 this disclosure. Furthermore, the steps of the method of the above embodiments do not have to be carried out in the order described above, and may be carried out in a different order as long as there is no technical inconsistency.

[0089] This disclosure can promote the use of ammonia, which leads to a reduction in CO2 emissions, and thus can contribute, for example, to Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable and modern energy," and Goal 13, "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0090] 1 1st mixer 2 Reactors 3 Second mixer 4 Third mixer 10 Fuel preheater 10A Fuel Preheater 10B Fuel Preheater 90 Control device 100 Combustion equipment B Burner BL1 Bypass Line (First Bypass Line) BL2 Bypass Line (Second Bypass Line) H Heating means L1 Fuel Supply Line L2 Oxidizer Supply Line L3 Nitrogen Supply Line S1 Temperature Sensor S2 Temperature Sensor V1 valve (first valve) V4 valve (second valve)

Claims

1. A first mixer installed in a fuel supply line connected to a combustion facility that burns ammonia-containing fuel, The fuel supply line supplies ammonia to the first mixer. The first mixer is connected to an oxidizer supply line that supplies an oxidizer, and mixes ammonia flowing through the fuel supply line with the oxidizer from the oxidizer supply line to produce a mixed gas. First mixer, A reactor located downstream of the first mixer in the fuel supply line, The reactor contains a catalyst that accelerates the reaction of ammonia and causes an exothermic reaction. The catalyst causes the exothermic reaction by at least a portion of the ammonia in the mixed gas supplied from the first mixer, thereby heating the mixed gas. Reactor and A first valve is provided in the oxidizing agent supply line and adjusts the flow rate of the oxidizing agent supplied to the first mixer, A control device that is communicatively connected to the first valve, Equipped with, The control device is While the fuel containing ammonia is being supplied to the combustion equipment, the first valve is controlled to continue supplying the oxidizer to the reactor. Configured to perform, Fuel preheater.

2. The fuel preheater according to claim 1, comprising a second mixer provided downstream of the reactor in the fuel supply line, the second mixer being connected to the oxidizer supply line by a first bypass line, and mixing the mixed gas supplied from the reactor with the oxidizer supplied from the first bypass line.

3. The fuel supply line further comprises a temperature sensor provided downstream of the reactor for measuring the temperature of the mixed gas, The control device is connected to the temperature sensor in a manner that allows communication. The control device stores a predetermined threshold value associated with the temperature at which the material forming the fuel supply line begins to undergo nitriding. The control device controls the first valve to adjust the flow rate of the oxidizer supplied to the first mixer so that the temperature of the mixed gas measured by the temperature sensor is below the threshold. A fuel preheater according to claim 1 or 2.

4. The fuel preheater according to claim 1, wherein the reactor includes heating means for heating the catalyst, and the heating means includes a heater.

5. The fuel preheater according to claim 1, wherein the reactor includes a heating means for heating the catalyst, and the heating means includes a first heat exchanger that heats the catalyst with exhaust gas from the combustion equipment.

6. The fuel preheater according to claim 1, wherein the reactor includes a heating means for heating the catalyst, and the heating means includes a second heat exchanger for heating the catalyst with steam extracted from the combustion equipment.

7. The fuel preheater according to claim 1, comprising a third mixer provided downstream of the reactor in the fuel supply line, the third mixer being connected by a second bypass line to a position upstream of the first mixer in the fuel supply line, and the third mixer mixing the mixed gas supplied from the reactor with ammonia supplied from the second bypass line.

8. A second valve is provided upstream of the first mixer in the fuel supply line and adjusts the flow rate of ammonia supplied to the first mixer, A temperature sensor is provided downstream of the reactor in the fuel supply line to measure the temperature of the mixed gas, Furthermore, The control device is connected to the second valve and the temperature sensor in a manner that allows communication between them. The control device stores a predetermined threshold value associated with the temperature at which the material forming the fuel supply line begins to undergo nitriding. The control device controls the second valve to adjust the flow rate of ammonia supplied to the first mixer so that the temperature of the mixed gas measured by the temperature sensor is below the threshold. A fuel preheater according to claim 1 or 7.

9. The fuel preheater according to claim 1, wherein the fuel preheater supplies the mixed gas to a plurality of burners of the combustion equipment.

10. The fuel preheater according to claim 1, wherein the exothermic reaction in the catalyst of the reactor is catalytic combustion.

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