Ammonia fuel SOFC power generation system

Abstract

The utility model relates to the technical field of power generation equipment, and particularly discloses an ammonia fuel SOFC (solid oxide fuel cell) power generation system, which comprises a fuel supply and processing subsystem, an ammonia fuel pre-heating and cracking subsystem and an ammonia fuel pre-heating and cracking subsystem, the air supply subsystem is used for providing air and preheating the air; the combustion heat supply subsystem serves as a fuel combustion place and supplies heat to the fuel supply and treatment subsystem and the air supply subsystem; the SOFC electric pile subsystem is used as a place for generating electrochemical reaction; and the electric energy conversion subsystem is used for performing power supply type conversion and storage on the current generated in the SOFC pile subsystem. Fuel used by the system is ammonia fuel, other methane auxiliary gas is not needed, ammonia water is not needed, the step of ammonia water vaporization is not needed, energy consumption is reduced, and the whole power generation system is simple in structure, high in power generation efficiency and high in raw material utilization rate.

Description

TECHNICAL FIELD

[0001] The utility model relates to power generation equipment technical field, specifically, it relates to a kind of ammonia fuel SOFC power generation system. BACKGROUND

[0002] Solid oxide fuel cell (SOFC) is a kind of system using electrochemical reaction to generate electricity. For example, the SOFC power generation system of natural gas is under high temperature to reform fuel into hydrogen, and hydrogen ion is ionized into hydrogen ion under the action of cell unit, and oxygen ion in cathode combines to generate water, and releases electric energy.

[0003] The hydrogen supply part of traditional SOFC power generation system is alkane or alcohol reforming hydrogen, however, the fuel using cost of this kind of fuel is higher than that of ammonia, and the tail gas emission contains carbon dioxide, which will increase the greenhouse effect, and the tail gas emission of ammonia fuel SOFC power generation system is nitrogen and water vapor, does not contain carbon dioxide, and is friendly to environment. Therefore, ammonia fuel SOFC power generation system also gradually gets the attention of researchers.

[0004] As disclosed in the patent with authorized announcement number CN113540541B, a SOFC using ammonia water as fuel and a cascading power generation system and operating method thereof are disclosed, the SOFC using ammonia water as fuel includes: an anode layer, an electrolyte layer, a separation layer and a cathode layer; the anode is connected with compressed ammonia water; the mass concentration of the ammonia water is preferably 0.65-0.85, and the utilization rate of hydrogen generated by decomposition of ammonia in the SOFC is 75%. However, the system needs a large bottom circulating system composed of ammonia water turbine, ammonia water separator and other instruments to realize operation, and the equipment system is complex.

[0005] The patent application with publication number CN116470107A also discloses a high-efficiency power generation system of ammonia fuel solid oxide fuel cell, the system includes a porous medium burner, a mixer, an ammonia gas heat exchanger, a first air heat exchanger, a second air heat exchanger, a fan, a solid oxide fuel cell SOFC stack, a supplementary combustor, a reformer, a hydrogen separator, a methane gas cylinder and an ammonia gas cylinder and a plurality of valves connected in a predetermined manner. However, the system still needs methane gas as auxiliary, and does not really realize the full-ammonia fuel solid oxide fuel cell power generation system.

[0006] The ammonia cracking hydrogen production is to produce hydrogen (H2) by decomposing ammonia (NH3), which is an endothermic reaction, and needs to be carried out at high temperature and under the action of a catalyst, and the reaction temperature is 750-850 DEG C. The heating methods of the ammonia cracking hydrogen production include electric heating or fuel combustion heating. The electric heating method needs additional power consumption, so that the overall operation efficiency of the SOFC power generation system is low. The fuel combustion heating directly releases heat, and the fuel does not participate in the electrochemical reaction and discharge, so the power generation efficiency of the SOFC power generation system is also reduced. Practical new type content

[0007] The utility model discloses a kind of more energy-efficient ammonia fuel SOFC power generation systems, to solve the problem of pure ammonia fuel power generation and power generation system complex, power generation efficiency is not high in prior art.

[0008] The utility model discloses a kind of ammonia fuel SOFC power generation systems, comprising:

[0009] Fuel supply and processing subsystem, for providing ammonia fuel and preheating and cracking to ammonia fuel;

[0010] Air supply subsystem, for providing air and preheating to air;

[0011] Combustion heating subsystem, as the place of fuel combustion and heating to fuel supply and processing subsystem and air supply subsystem;

[0012] SOFC stack subsystem, as the place of electrochemical reaction;

[0013] And power conversion subsystem, for power type conversion and storage to the current generated in SOFC stack subsystem;

[0014] The gas inlet of the fuel supply and processing subsystem is connected with ammonia supply pipeline, the gas outlet of the fuel supply and processing subsystem is connected with the anode feed port of SOFC stack subsystem, the air inlet of the air supply subsystem is connected with air supply pipeline, the air outlet of the air supply subsystem is connected with the cathode feed port of SOFC stack subsystem, the inlet of the combustion heating subsystem is connected with the anode tail gas outlet and the cathode tail gas outlet of SOFC stack subsystem, the outlet of the combustion heating subsystem is connected with the flue gas inlet of fuel supply and processing subsystem and the flue gas inlet of air supply subsystem, the flue gas outlet of fuel supply and processing subsystem and the flue gas outlet of fuel supply and processing subsystem are connected with atmosphere, and the current outlet of SOFC stack subsystem is connected with the current inlet of power conversion subsystem.

[0015] Compared with the prior art, the fuel used in the whole process is ammonia fuel, no other methane auxiliary gas is needed, ammonia gas instead of ammonia water is directly used, no ammonia water vaporization step is needed, energy consumption is saved, the whole power generation system is simple in structure, high in power generation efficiency, and high in raw material utilization rate.

[0016] In a possible implementation, the fuel supply and treatment subsystem includes an ammonia gas heat exchanger and an ammonia gas cracker, the fuel side inlet of the ammonia gas heat exchanger is connected with an ammonia gas supply pipeline, the flue gas inlet of the ammonia gas heat exchanger is connected with the flue gas outlet of the air supply subsystem, the fuel side outlet of the ammonia gas heat exchanger is connected with the fuel gas inlet of the ammonia gas cracker, the fuel side outlet of the ammonia gas cracker is connected with the anode inlet of the SOFC stack subsystem, the flue gas inlet of the ammonia gas cracker is connected with the flue gas outlet of the combustion heat supply subsystem, the flue gas outlet of the ammonia gas cracker is connected with the flue gas inlet of the air supply subsystem, and the flue gas outlet of the ammonia gas heat exchanger is connected with the atmosphere.

[0017] In the above scheme, the ammonia gas heat exchanger is used to preheat the ammonia gas coming from outside, the preheated ammonia gas is cracked into hydrogen and nitrogen in the ammonia gas cracker, and the hydrogen is introduced into the anode of the SOFC stack subsystem to perform an electrochemical reaction. The flue gas after preheating the ammonia gas is cooled and discharged into the atmosphere.

[0018] In a possible implementation, the ammonia gas cracker is filled with an ammonia cracking hydrogen production catalyst.

[0019] In a possible implementation, a hydrogen supply pipeline is further connected to the fuel gas inlet of the ammonia gas cracker. This hydrogen supply pipeline is used as a heat source to start the raw material when the system starts from zero. In the initial state, the system needs heat to preheat the ammonia gas so as to crack the ammonia gas into hydrogen and nitrogen, thereby starting the subsequent electrochemical reaction. Therefore, the heat required by the system at the beginning is derived from the high-temperature flue gas generated by the combustion of the external hydrogen in the combustion heat supply subsystem.

[0020] In a possible implementation, the air supply subsystem includes an air supply fan and an air preheater, the preheated air outlet of the air preheater is connected with the cathode inlet of the SOFC stack subsystem, the flue gas inlet of the air preheater is connected with the flue gas outlet of the ammonia gas cracker, the flue gas outlet of the air preheater is connected with the flue gas inlet of the ammonia gas heat exchanger, and the air supply fan is connected with an air supply pipeline.

[0021] In the above scheme, the air supply fan transmits the external air to the air preheater, and the preheated air directly enters the cathode of the SOFC stack subsystem to participate in the electrochemical reaction. The flue gas outlet of the air preheater is connected with the flue gas inlet of the ammonia gas heat exchanger, so that the flue gas heat generated by the system is absorbed by the air preheating and then absorbed by the ammonia gas heat exchange, so that the energy recycling of the system is more sufficient, and the system is simplified while being more efficient.

[0022] In a possible implementation, the combustion heat supply subsystem comprises a burner, the inlet of the burner is connected with the anode tail gas outlet and the cathode tail gas outlet of the SOFC stack subsystem, and the outlet of the burner is connected with the flue gas inlet of the ammonia gas cracker.

[0023] In a possible implementation, the combustion heat supply subsystem further comprises an oxygen sensor, which is arranged on the pipeline connecting the flue gas outlet of the burner with the flue gas inlet of the ammonia gas cracker. The oxygen sensor can monitor the oxygen content in the flue gas from the burner, and control the flow of air to be supplied by the air fan according to the parameter, so as to ensure the normal operation of the system.

[0024] In a possible implementation, the electric energy conversion subsystem comprises a converter and a battery, the current outlet of the SOFC stack subsystem is connected with the current inlet of the battery, and the current outlet of the battery is connected with the current inlet of the converter.

[0025] In a possible implementation, the converter is a DC / DC converter or a DC / AC converter. The converter is used to convert the direct current generated by the electrochemical reaction in the electric energy conversion subsystem into alternating current, which is suitable for subsequent use.

[0026] The utility model discloses the beneficial effect that:

[0027] 1、The fuel used in the utility model is ammonia gas, and no hydrocarbon combustion-supporting gas such as methane is needed, which is economical and efficient, and the exhaust gas discharged is nitrogen and water vapor, does not contain carbon dioxide, is friendly to the environment, and will not increase the greenhouse effect.

[0028] 2、In the reforming hydrogen production process of alkane or alcohol fuel, water vapor needs to participate in the reaction, that is, water needs to be added and vaporized, and in the utility model, ammonia gas cracking does not need water vapor to participate, and there is no water vaporization heat absorption process, so that the system efficiency is higher.

[0029] 3、The anode tail gas in the SOFC is discharged to the burner, and after combustion, heat is supplied to the fuel supply and treatment subsystem and the air supply subsystem, without consuming additional fuel or electric power, and the system heat utilization efficiency is high. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1The utility model discloses a structure diagram of ammonia fuel SOFC power generation system.

[0031] In the drawing, 1, fuel supply and processing subsystem;11, ammonia gas heat exchanger;12, ammonia gas cracker;2, air supply subsystem;21, air supply fan;22, air preheater;3, combustion heat supply subsystem;31, combustor;32, oxygen sensor;4, SOFC stack subsystem;5, electric energy conversion subsystem;51, converter;52, battery. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purpose, feature and advantage of the utility model more obvious and easy to understand, the specific embodiment of the utility model is explained in detail below.It is to be explained that the following embodiments are only used for explaining the implementation method and typical parameter of the utility model, and are not used for limiting the parameter range of the utility model described, and the reasonable change deduced still is in the protection scope of the utility model claim.

[0033] In the description of the embodiment of the application, it is to be explained that, unless there is explicit definition and limitation, the term "connects" "connects" should be understood in broad sense, for example, can be fixed connection, also can be detachable connection, or integral connection;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through intermediate medium.For the person skilled in the art, the specific meaning of the above-mentioned term in the embodiment of the application can be understood according to the specific circumstances.

[0034] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0035] Reference Figure 1 As shown in the utility model discloses a kind of ammonia fuel SOFC power generation system, comprising: fuel supply and processing subsystem 1, for providing ammonia fuel and preheating and cracking to ammonia fuel;Air supply subsystem 2, for providing air and preheating to air;Combustion heat supply subsystem 3, as the place of fuel combustion and heat supply to fuel supply and processing subsystem 1 and air supply subsystem 2;SOFC stack subsystem 4, as the place of electrochemical reaction;And electric energy conversion subsystem 5, for converting power type to the current generated in SOFC stack subsystem and storage.

[0036] The fuel supply and processing subsystem 1 comprises an ammonia heat exchanger 11 and an ammonia cracker 12. The fuel side inlet of the ammonia heat exchanger 11 is connected with an ammonia supply pipeline. The ammonia from outside is preheated to 750-850℃ in the ammonia heat exchanger 11 and then enters the ammonia cracker 12. The fuel side outlet of the ammonia heat exchanger 11 is connected with the fuel gas inlet of the ammonia cracker 12. The ammonia cracker 12 is filled with ammonia cracking hydrogen production catalyst which can catalyze the high-temperature ammonia at 750-850℃ to hydrogen and nitrogen. The ammonia cracking hydrogen production catalyst used herein can be any catalyst on the market which can catalyze the ammonia cracking to hydrogen and nitrogen. Preferably, a solid ammonia cracking hydrogen production catalyst such as nickel catalyst is used. The fuel side outlet of the ammonia cracker 12 is connected with the anode inlet of the SOFC stack subsystem 4. That is, the hydrogen obtained by cracking directly enters the anode of the SOFC stack subsystem for electron loss oxidation electrochemical reaction.

[0037] The fuel gas inlet pipeline of the ammonia cracker 12 is also connected with a hydrogen supply pipeline. This hydrogen supply pipeline is used to supply starting fuel for the heat source of the system starting from zero. At the initial operation of the system, the hydrogen directly supplied from outside is introduced into the combustion heat supply subsystem 3 to be ignited and burned. The heat generated after combustion is used to preheat ammonia and air, to provide a high-temperature environment for the ammonia cracker 12, and then the ammonia fuel is cracked and the subsequent electrochemical reaction produces tail gas which is recycled as the next combustion heat supply subsystem 3 combustion process.

[0038] The air supply subsystem 2 comprises an air supply fan 21 and an air preheater 22. The preheated air outlet of the air preheater 21 is connected with the cathode inlet of the SOFC stack subsystem 4. The air supply fan 21 is connected with an air supply pipeline. The air supply fan 21 compresses the air from outside and pumps it into the air preheater 22 of the system. The air is heated in the air preheater 22 and then enters the cathode of the SOFC stack subsystem 4 to undergo electron receiving reduction reaction. The flue gas inlet of the air preheater 22 is connected with the flue gas outlet of the ammonia cracker 12. The flue gas outlet of the air preheater 22 is connected with the flue gas inlet of the ammonia heat exchanger 11. The flue gas outlet of the air preheater 22 is connected with the flue gas inlet of the ammonia heat exchanger 11. The flue gas outlet of the ammonia heat exchanger 11 is connected with the atmosphere. The flue gas heat generated by the system is absorbed by the air preheater 22 and then absorbed by the ammonia heat exchanger, so that the energy recycling of the system is more sufficient and the system is simplified while the energy utilization is more sufficient. The flue gas generated by combustion is actually nitrogen and water vapor which becomes nitrogen and water after heat exchange and can be directly discharged into the atmosphere.

[0039] The combustion heat supply subsystem 3 comprises a burner 31, the inlet of the burner 31 is connected with the anode tail gas outlet and the cathode tail gas outlet of the SOFC stack subsystem 4, and the outlet of the burner 31 is connected with the flue gas inlet of the ammonia cracker 12. The combustion reaction in the system burner 31 is the combustion of the mixed gas composed of the anode tail gas hydrogen and the cathode tail gas oxygen from the SOFC stack subsystem 4, and the high-temperature flue gas generated after combustion firstly enters the ammonia cracker 12 to provide a high-temperature environment for ammonia cracking. Then the flue gas enters the air preheater 22 and the ammonia preheater 11 to preheat the air and the ammonia. The combustion heat supply subsystem 3 further comprises an oxygen sensor 32, which is arranged on the pipeline connecting the outlet of the burner 31 with the flue gas inlet of the ammonia cracker 12. The oxygen sensor 32 can monitor the oxygen content in the flue gas from the burner 31, and judge whether the hydrogen in the anode tail gas is completely combusted, and further control the flow of the air supplied by the air blower 21, so as to ensure the normal operation of the system and realize the automatic adaptation of complete combustion.

[0040] In the SOFC stack subsystem 4, the electrochemical reactions occurring in the anode and the cathode at the same time generate direct current in the system. The direct current directly enters the electric energy conversion subsystem 5 for conversion or storage. The electric energy conversion subsystem 5 comprises a converter 51 and a storage battery 52, the current outlet of the SOFC stack subsystem 4 is connected with the storage battery 52, and the current outlet of the storage battery 52 is connected with the current inlet of the converter 51. The converter 51 can be a DC / DC converter or a DC / AC converter. After conversion by the converter, alternating current that can be connected to the grid is obtained.

[0041] In summary, the working principle of the utility model is that the hydrogen and oxygen from the anode tail gas outlet and the cathode tail gas outlet of the SOFC stack subsystem 4 are combusted in the combustion heat supply subsystem 3, the high-temperature flue gas after combustion enters the fuel supply and treatment subsystem 3 and the air supply subsystem 2 to preheat the ammonia and the air from the outside, so that the high-temperature ammonia enters the fuel supply and treatment subsystem 1 to be cracked (the high-temperature flue gas also provides a high-temperature environment in the ammonia cracker 12), the cracked gas enters the SOFC stack subsystem 4 to generate direct current through chemical reaction, the tail gas generated by the chemical reaction of the SOFC stack subsystem 4 enters the combustion heat supply subsystem 3 again to be combusted, so as to realize cyclic heat supply, and finally the cold flue gas after preheating of the ammonia and the air is directly discharged into the atmosphere from the flue gas outlet of the fuel supply and treatment subsystem 1, so as to realize sustainable operation of the whole system.

[0042] In the description of the embodiments of the present application, it should be noted that the terms "inner", "outer", and the like indicating the direction or positional relationship in the description of the present application are based on the direction or positional relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or member must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0043] The above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An ammonia-fueled SOFC power generation system, characterized by comprising: The system comprises: a fuel supply and treatment subsystem (1) for providing ammonia fuel and preheating and cracking the ammonia fuel; an air supply subsystem (2) for providing air and preheating the air; a combustion heat supply subsystem (3) as a place for fuel combustion and supplying heat to the fuel supply and treatment subsystem and the air supply subsystem; an SOFC stack subsystem (4) as a place for electrochemical reaction; and an electric energy conversion subsystem (5) for converting the electric current generated in the SOFC stack subsystem into a power supply type and storing it; the fuel gas inlet of the fuel supply and treatment subsystem (1) is connected to an ammonia gas supply pipeline, the fuel gas outlet of the fuel supply and treatment subsystem (1) is connected to the anode feed inlet of the SOFC stack subsystem (4), the air inlet of the air supply subsystem (2) is connected to an air supply pipeline, the air outlet of the air supply subsystem (2) is connected to the cathode feed inlet of the SOFC stack subsystem (4), the inlet of the combustion heat supply subsystem (3) is connected to the anode tail gas outlet and the cathode tail gas outlet of the SOFC stack subsystem (4), the outlet of the combustion heat supply subsystem (3) is connected to the flue gas inlet of the fuel supply and treatment subsystem (1) and the flue gas inlet of the air supply subsystem (2), the flue gas outlet of the fuel supply and treatment subsystem (1) and the flue gas outlet of the fuel supply and treatment subsystem (1) are connected to the atmosphere, and the current outlet of the SOFC stack subsystem (4) is connected to the current inlet of the electric energy conversion subsystem (5).

2. The ammonia-fueled SOFC power generation system according to claim 1, characterized by, The fuel supply and treatment subsystem (1) comprises an ammonia gas heat exchanger (11) and an ammonia gas cracker (12), the fuel gas inlet of the ammonia gas heat exchanger (11) is connected to an ammonia gas supply pipeline, the flue gas inlet of the ammonia gas heat exchanger (11) is connected to the flue gas outlet of the air supply subsystem (2), the fuel gas outlet of the ammonia gas heat exchanger (11) is connected to the fuel gas inlet of the ammonia gas cracker (12), the fuel gas outlet of the ammonia gas cracker (12) is connected to the anode inlet of the SOFC stack subsystem (4), the flue gas inlet of the ammonia gas cracker (12) is connected to the outlet of the combustion heat supply subsystem (3), the flue gas outlet of the ammonia gas cracker (12) is connected to the flue gas inlet of the air supply subsystem (2), and the flue gas outlet of the ammonia gas heat exchanger (11) is connected to the atmosphere.

3. The ammonia-fueled SOFC power generation system according to claim 2, characterized by, The ammonia gas cracker (12) is filled with an ammonia cracking hydrogen production catalyst.

4. The ammonia-fueled SOFC power generation system according to claim 2, characterized by, A hydrogen supply pipeline is further connected to the fuel gas inlet pipeline of the ammonia gas cracker (12).

5. The ammonia-fueled SOFC power generation system according to claim 2, wherein The air supply subsystem (2) comprises an air supply fan (21) and an air preheater (22), the air outlet of the air preheater (22) is connected to the cathode inlet of the SOFC stack subsystem (4), the flue gas inlet of the air preheater (22) is connected to the flue gas outlet of the ammonia gas cracker (12), the flue gas outlet of the air preheater (22) is connected to the flue gas inlet of the ammonia gas heat exchanger (11), and the air supply fan (21) is connected to an air supply pipeline.

6. The ammonia-fueled SOFC power generation system according to claim 1, wherein The combustion heat supply subsystem (3) comprises a burner (31), the inlet of the burner (31) is connected with the anode tail gas outlet and the cathode tail gas outlet of the SOFC stack subsystem (4), and the outlet of the burner (31) is connected with the flue gas inlet of the ammonia cracker (12).

7. The ammonia-fueled SOFC power generation system according to claim 6, characterized by The combustion heat supply subsystem (3) further comprises an oxygen sensor (32), which is arranged on the pipeline connecting the outlet of the burner (31) with the flue gas inlet of the ammonia cracker (12).

8. The ammonia-fueled SOFC power generation system according to claim 1, characterized by, The electric energy conversion subsystem (5) comprises a converter (51) and a battery (52), the current outlet of the SOFC stack subsystem (4) is connected with the current inlet of the battery (52), and the current outlet of the battery (52) is connected with the current inlet of the converter (51).

9. The ammonia-fueled SOFC power generation system according to claim 8, characterized by, The converter (51) is a DC / DC converter or a DC / AC converter.

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