Methane generator and engine system

Abstract

To provide a methane generation device capable of generating methane without separately providing a hydrogen supply source, and an engine system.SOLUTION: A methane generation device 40 comprises: a decomposition device 41 that decomposes ammonia NH3; and a methanation device 42 that receives hydrogen H2 produced by the decomposition of ammonia NH3 in the decomposition device 41, and generates methane CH4 by a methanation reaction between the hydrogen H2 from the decomposition device 41 and carbon dioxide CO2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a methanator and engine system. [Background technology]

[0002] Conventionally, methane generation devices include those that separate carbon dioxide from the exhaust gas of a gas engine using a separation device, generate methane using the separated carbon dioxide and hydrogen in a methanation device, and supply the generated methane as fuel for the gas engine.

[0003] In addition, since the above-mentioned conventional methane generation apparatus uses well-known technology that is generally known in the technical field, description of prior art literature information will be omitted. Summary of the Invention [Problem to be solved by the invention]

[0004] The methane generator requires a hydrogen supply source to supply hydrogen for the methanation reaction to the methanation device. Therefore, when the methane generator is installed on a ship that does not have a hydrogen supply source, a separate hydrogen supply source must be provided on the ship. Since ships have space restrictions, it is difficult to install both the methane generator and the hydrogen supply source on the ship.

[0005] An object of the present invention is to provide a methane generator and an engine system capable of generating methane without providing a separate hydrogen source. [Means for solving the problem]

[0006] One aspect of the present invention provides a methane generation apparatus including a decomposition device that decomposes ammonia, and a methanation device that is supplied with hydrogen produced by the decomposition of ammonia in the decomposition device and produces methane by a methanation reaction between carbon dioxide and the hydrogen from the decomposition device.

[0007] According to this configuration, the methanation device is supplied with hydrogen produced by decomposition of ammonia in the decomposition device, and the methanation device produces methane by a methanation reaction between carbon dioxide and hydrogen from the decomposition device. As a result, when the methanation device is installed on a ship having an ammonia supply source, it is not necessary to provide a separate hydrogen supply source for supplying hydrogen for the methanation reaction to the methanation device. As a result, methane can be produced without providing a separate hydrogen supply source. In other words, even when the methane generation device is installed on a ship having an ammonia supply source but not a hydrogen supply source, it can produce methane. The installation location of the methane generation device is not limited to a ship, and it may be installed in a factory, a research institute, a business establishment, etc.

[0008] Another aspect of the present invention provides an engine system including an ammonia engine that burns ammonia, and the above-mentioned methane generation device to which carbon dioxide generated by the combustion of ammonia in the ammonia engine is supplied, the methanation device generating methane by a methanation reaction between hydrogen from the decomposition device and carbon dioxide from the ammonia engine, and supplying the generated methane to the ammonia engine.

[0009] According to this configuration, the methanation device generates methane from carbon dioxide generated by the combustion of ammonia in the ammonia engine and hydrogen generated by decomposition of ammonia in the decomposition device. The methanation device also supplies the generated methane to the ammonia engine. This allows the carbon dioxide generated in the ammonia engine to be converted into methane and used as fuel for the ammonia engine.

[0010] When an engine system collects and stores carbon dioxide contained in exhaust gas discharged from an ammonia engine in order to suppress the release of carbon dioxide into the atmosphere, a separation device for separating the carbon dioxide and a storage device for storing the carbon dioxide are required. In contrast, with the above configuration, the carbon dioxide contained in exhaust gas discharged from the ammonia engine is converted into methane, which serves as fuel for the ammonia engine. Therefore, it is possible to suppress the release of carbon dioxide into the atmosphere without providing a separation device and a storage device. This is particularly useful when the engine system is an engine system installed on a ship, since there is no need to install a separation device and a storage device on the ship, which has installation space limitations.

[0011] In one embodiment, the engine system includes an ammonia source that supplies ammonia to the ammonia engine and to the cracker.

[0012] According to this configuration, the ammonia supply source supplies ammonia to both the ammonia engine and the decomposition device, which makes it possible to reduce the size of the engine system compared to a case in which a plurality of ammonia supply sources for supplying ammonia to each of the ammonia engine and the decomposition device are provided in the engine system.

[0013] In one embodiment, the cracker supplies a portion of the hydrogen produced by the cracking of ammonia to the ammonia engine.

[0014] According to this configuration, hydrogen can be supplied as a combustion improver to the ammonia engine without providing a separate hydrogen supply source to the engine system, and as a result, the combustion efficiency of the ammonia engine can be improved. Effect of the Invention

[0015] According to the present invention, it is possible to provide a methane generator and an engine system capable of generating methane without providing a separate hydrogen supply source. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram showing a configuration of an engine system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a methane generator and an engine system according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0018] FIG. 1 is a block diagram showing a configuration of an engine system 1 according to an embodiment of the present invention.

[0019] 1, an engine system 1 includes an ammonia supply source 10, an ammonia engine 20, an exhaust gas purification device 30, and a methane generator 40. The methane generator 40 includes a decomposition device 41 that decomposes ammonia NH3, and a methanation device 42 that generates methane CH4 by a methanation reaction between carbon dioxide CO2 and hydrogen H2. The engine system 1 of this embodiment is an engine system for a ship.

[0020] The ammonia supply source 10 of this embodiment is a storage tank that stores liquid ammonia NH3. The ammonia supply source 10 supplies the stored ammonia NH3 to the ammonia engine 20 and the decomposition device 41. The liquid ammonia NH3 stored in the ammonia supply source 10 is vaporized by a vaporization device (not shown), thereby supplying gaseous ammonia NH3 to the ammonia engine 20 and the methane generation device 40.

[0021] The ammonia engine 20 is supplied with gaseous ammonia NH3 from the ammonia supply source 10. The ammonia engine 20 is a gas engine that generates power by combusting the gaseous ammonia NH3 (ammonia gas) supplied from the ammonia supply source 10. The ammonia engine 20 is a marine diesel engine. The ammonia engine 20 of this embodiment uses heavy oil, particularly heavy oil A, as pilot fuel.

[0022] The ammonia engine 20 is supplied with hydrogen H2 from the decomposition device 41. The ammonia engine 20 of this embodiment uses the hydrogen H2 supplied from the decomposition device 41 as a combustion improver.

[0023] Methane CH4 is supplied to the ammonia engine 20 from the methanation device 42. The ammonia engine 20 of the present embodiment uses the methane CH4 supplied from the methanation device 42 as part of the fuel.

[0024] The exhaust gas generated by the combustion of ammonia (NH3) in the ammonia engine 20 contains carbon dioxide (CO2), nitrous oxide (N2O), and nitrogen oxide (NO x and unburned ammonia NH3.

[0025] The exhaust gas purification device 30 is supplied with exhaust gas from the ammonia engine 20. The exhaust gas purification device 30 purifies the exhaust gas of the ammonia engine 20. In other words, the exhaust gas purification device 30 purifies nitrous oxide (NO) and nitrogen oxide (NO) contained in the exhaust gas of the ammonia engine 20. x and unburned ammonia NH3.

[0026] The exhaust gas purification device 30 decomposes nitrous oxide N2O contained in the exhaust gas of the ammonia engine 20 to generate nitrogen N2 and oxygen O2.

[0027] The exhaust gas purification device 30 purifies nitrogen oxides NO contained in the exhaust gas of the ammonia engine 20. x and ammonia NH3 to produce nitrogen N2 and water H2O.

[0028] The exhaust gas purification device 30 generates nitrogen N2 and water H2O through an oxidation reaction of unburned ammonia NH3 contained in the exhaust gas of the ammonia engine 20.

[0029] From the exhaust gas purification device 30, carbon dioxide CO2, nitrogen N2, oxygen O2, and water H2O are exhausted.

[0030] As described above, the methane generation device 40 includes the decomposition device 41 and the methanation device 42.

[0031] The decomposition device 41 is supplied with ammonia NH3 from the ammonia supply source 10. The decomposition device 41 decomposes (cracks) the ammonia NH3 supplied from the ammonia supply source 10 to generate nitrogen N2 and hydrogen H2. The decomposition device 41 supplies a portion of the generated hydrogen H2 to the ammonia engine 20. The decomposition device 41 also supplies a portion of the generated hydrogen H2 to the methanation device 42.

[0032] A portion of the exhaust gas that has passed through the exhaust gas purification device 30 is supplied to the methanation device 42. Alternatively, the entire amount of exhaust gas that has passed through the exhaust gas purification device 30 may be supplied to the methanation device 42. The methanation device 42 generates methane CH4 by subjecting carbon dioxide CO2 in the exhaust gas supplied from the exhaust gas purification device 30 to a methanation reaction using a catalyst with hydrogen H2 supplied from the decomposition device 41. The methanation device 42 supplies the generated methane CH4 to the ammonia engine 20. The methanation reaction is represented by the following chemical reaction formula. CO2+ 4H2→ CH4+ 2H2O

[0033] In the present embodiment, the exhaust gas discharged from the ammonia engine 20 and passed through the exhaust gas purification device 30 is supplied to the methanation device 42, but this is not limited thereto. The engine system 1 may include a separation device that separates carbon dioxide CO2 from the gas discharged from the exhaust gas purification device 30. In this case, the methanation device 42 may be supplied with the carbon dioxide CO2 separated by the separation device.

[0034] According to the methane generation device 40 of this embodiment, hydrogen H2 generated by decomposition of ammonia NH3 in the decomposition device 41 is supplied to the methanation device 42, and the methanation device 42 generates methane CH4 by methanation reaction of carbon dioxide CO2 and hydrogen H2 from the decomposition device 41. As a result, when the methanation device 42 is installed on a ship having an ammonia supply source 10 as in this embodiment, it is not necessary to separately provide a hydrogen supply source that supplies hydrogen for the methanation reaction to the methanation device 42. As a result, methane CH4 can be generated without separately providing a hydrogen supply source. In other words, even if the methane generation device 40 is installed on a ship having an ammonia supply source 10 but not a hydrogen supply source, it can generate methane CH4. The installation location of the methane generation device 40 is not limited to a ship, and it may be installed in a factory, a research institute, a business office, etc.

[0035] According to the engine system 1 according to this embodiment, the methanation device 42 generates methane CH4 from carbon dioxide CO2 generated by combustion of ammonia NH3 in the ammonia engine 20 and hydrogen H2 generated by decomposition of ammonia NH3 in the decomposition device 41. The methanation device 42 also supplies the generated methane CH4 to the ammonia engine 20. This allows the carbon dioxide CO2 generated in the ammonia engine 20 to be converted into methane CH4 and used as fuel for the ammonia engine 20.

[0036] In order to suppress the release of carbon dioxide CO2 into the atmosphere, when the engine system 1 collects and stores the carbon dioxide CO2 contained in the exhaust gas discharged from the ammonia engine 20, a separation device that separates the carbon dioxide CO2 from the exhaust gas and a storage device that stores the carbon dioxide CO2 are required. In contrast, according to the above configuration, the carbon dioxide CO2 contained in the exhaust gas discharged from the ammonia engine 20 is converted into methane CH4, which serves as fuel for the ammonia engine 20. Therefore, it is possible to suppress the release of carbon dioxide CO2 into the atmosphere without providing a separation device and a storage device. When the engine system 1 is an engine system mounted on a ship as in this embodiment, it is particularly useful because there is no need to install a separation device and a storage device on the ship, which has installation space restrictions.

[0037] According to the engine system 1 according to this embodiment, the ammonia supply source 10 supplies ammonia NH3 to both the ammonia engine 20 and the decomposition device 41. Therefore, compared to a case in which a plurality of ammonia supply sources 10 for supplying ammonia NH3 to each of the ammonia engine 20 and the decomposition device 41 are provided in the engine system 1, the engine system 1 can be made smaller in size.

[0038] According to the engine system 1 according to this embodiment, hydrogen H2 can be supplied as a combustion improver to the ammonia engine 20 without providing a separate hydrogen supply source to the engine system 1. As a result, the combustion efficiency of the ammonia engine 20 can be improved.

[0039] Although the present invention has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art, and such changes and modifications should be understood to be included within the scope of the present disclosure as defined by the appended claims unless they depart therefrom.

[0040] For example, in the present embodiment, the carbon dioxide CO2 contained in the exhaust gas discharged from the ammonia engine 20 is used in the methanation reaction in the methanation device 42, but the present invention is not limited to this. For example, the engine system 1 may have a carbon dioxide supply source such as a carbon dioxide tank, and the carbon dioxide CO2 supplied from the carbon dioxide tank may be used in the methanation reaction in the methanation device 42. [Explanation of symbols]

[0041] 1 Engine System 10. Ammonia Source 20 Ammonia Engine 30 Exhaust gas purification device 40 Methane Generator 41 Decomposition equipment 42 Methanation device

Claims

1. An engine system installed on a ship, comprising: an ammonia engine, which is a diesel engine that uses ammonia as the main fuel and heavy oil as the pilot fuel; A decomposition device for decomposing ammonia; a methanation device that generates methane by a methanation reaction between hydrogen generated by the decomposition of ammonia in the decomposition device and carbon dioxide contained in exhaust gas discharged from the ammonia engine; Equipped with Supplying methane produced in the methanation device to the ammonia engine; The engine system does not have a storage device for storing carbon dioxide.

2. The engine system of claim 1 , further comprising an ammonia source that supplies ammonia to the ammonia engine and to the cracker.

3. 3. The engine system according to claim 1, wherein the decomposition device supplies a portion of hydrogen produced by decomposition of ammonia to the ammonia engine.

4. An engine system as described in claim 1 or 2, wherein the methanation device directly supplies the generated methane to the ammonia engine.

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