System for switching different medium gases on line for solid oxide fuel cell system

Abstract

The utility model relates to the technical field of solid oxide fuel cells, and particularly provides a system for switching different medium gases on line for a solid oxide fuel cell system, which comprises a nitrogen pipeline, a hydrogen pipeline, a nitrogen-hydrogen mixed gas pipeline and an anode main pipeline, the anode main pipeline communicates with a nitrogen pipeline, a hydrogen pipeline and a nitrogen-hydrogen mixed gas pipeline through equal-diameter four-way pipe fittings, the nitrogen pipeline comprises a nitrogen cylinder, and the gas outlet end of the nitrogen cylinder communicates with a first electromagnetic valve through a pipeline. The anode pipeline disclosed by the utility model integrates all related gases of the anode pipeline, the gases can be conveniently switched on line and can be controlled by opening electromagnetic valves of different media, and the anode pipeline can be conveniently used for different test items and working conditions, so that the SOFC system is more convenient to operate.

Description

Technical Field

[0001] The utility model belongs to the technical field of solid oxide fuel cells, and particularly relates to a system for online switching of different medium gases in a solid oxide fuel cell system. Background Art

[0002] A solid oxide fuel cell (SOFC) is a new type of power generation device. Its high efficiency, pollution-free, all-solid-state structure, and wide adaptability to a variety of fuel gases are the basis for its wide application.

[0003] A solid oxide fuel cell monomer mainly consists of an electrolyte, an anode or fuel electrode, a cathode or air electrode, and a connector or bipolar plate.

[0004] The working principle of a solid oxide fuel cell is the same as that of other fuel cells. In principle, it is the "reverse" device of water electrolysis. Its single cell consists of an anode, a cathode, and a solid oxide electrolyte. The anode is the place where the fuel undergoes oxidation, and the cathode is the place where the oxidant is reduced. Both electrodes contain catalysts that accelerate the electrochemical reaction of the electrodes. When working, it is equivalent to a DC power source, with its anode being the negative electrode of the power source and the cathode being the positive electrode of the power source.

[0005] Fuel gas is continuously introduced on the anode side of the solid oxide fuel cell. For example: hydrogen (H2), methane (CH4), town gas, etc. The fuel gas is adsorbed on the catalytic anode surface and diffuses to the interface between the anode and the electrolyte through the porous structure of the anode. Oxygen or air is continuously introduced on the cathode side. Oxygen is adsorbed on the porous cathode surface. Due to the catalytic action of the cathode itself, O2 gains electrons to become O2-. Under the action of chemical potential, O2- enters the solid oxygen ion conductor that acts as an electrolyte. Due to diffusion caused by the concentration gradient, it finally reaches the interface between the solid electrolyte and the anode and reacts with the fuel gas. The lost electrons return to the cathode through the external circuit.

[0006] The anode pipeline of the existing SOFC system supplies gas from a gas cylinder to provide the gas source. The opening and closing of the gas circuit are controlled by a solenoid valve, and then the gas flow is adjusted by an MFC mass flow controller. After passing through the reformer, the gas finally enters the anode side of the SOFC stack.

[0007] The anode pipeline of the existing SOFC system can only pass one medium gas during each operation process and cannot switch other gas media online, which is inconvenient to use. Summary of the Utility Model

[0008] Aiming at the deficiencies of the existing technology, the purpose of the present utility model is to provide a system for online switching of different medium gases in a solid oxide fuel cell system, which solves the problem that the anode pipeline of the existing SOFC system can only conduct one medium gas during each operation process and cannot switch other gas media online, resulting in inconvenient use.

[0009] To achieve the above purpose, the present utility model provides the following technical solutions: A system for online switching of different medium gases in a solid oxide fuel cell system, including a nitrogen pipeline, a hydrogen pipeline, a nitrogen-hydrogen mixed pipeline, and an anode main pipeline. The anode main pipeline is respectively connected to the nitrogen pipeline, the hydrogen pipeline, and the nitrogen-hydrogen mixed pipeline through an equal-diameter four-way pipe fitting.

[0010] The nitrogen pipeline includes a nitrogen gas cylinder, and the outlet end of the nitrogen gas cylinder is connected with a solenoid valve I through a pipeline.

[0011] The hydrogen pipeline includes a hydrogen gas cylinder, and the outlet end of the hydrogen gas cylinder is connected with a solenoid valve II through a pipeline.

[0012] The nitrogen-hydrogen mixed pipeline includes a nitrogen-hydrogen mixed gas cylinder, and the outlet end of the nitrogen-hydrogen mixed gas cylinder is connected with a solenoid valve III through a pipeline.

[0013] The anode main pipeline includes a solenoid valve IV, a mass flow controller, a reformer, and an SOFC stack connected in sequence.

[0014] Preferably, the inlet end of the solenoid valve IV is connected with the outlet end of the equal-diameter four-way pipe fitting through a pipeline.

[0015] Preferably, the outlet ends of the solenoid valve I, the solenoid valve II, and the solenoid valve III are respectively connected with the inlet end of the equal-diameter four-way pipe fitting through pipelines.

[0016] Compared with the existing technology, the beneficial effects of the present utility model are:

[0017] 1. The anode pipeline in this solution integrates all the gases involved in the anode circuit, and it is convenient to switch gases online. It can be completed as long as the solenoid valves of different media are opened and controlled, which is convenient for different test items and working conditions, making the operation of the SOFC system more convenient.

[0018] 2. For the existing SOFC system, the anode pipeline needs to stop the operation of the SOFC system and then replace the gas cylinders of different media, which is troublesome and time-consuming. After adopting the anode pipeline for online switching of different medium gases in this solution, the time for replacing gas cylinders can be saved, and it is not necessary to stop the SOFC system from working. The SOFC system can switch different medium gases online without stopping work, which is convenient to use. Description of the Drawings

[0019] Figure 1This is a schematic structural diagram of the system of the present utility model.

[0020] In the figure: 1. Nitrogen gas pipeline; 101. Nitrogen gas cylinder; 102. Solenoid valve 1; 2. Hydrogen gas pipeline; 201. Hydrogen gas cylinder; 202. Solenoid valve 2; 3. Nitrogen-hydrogen mixed gas pipeline; 301. Nitrogen-hydrogen mixed gas cylinder; 302. Solenoid valve 3; 4. Anode main pipeline; 401. Solenoid valve 4; 402. Mass flow controller; 403. Reformer; 404. SOFC stack; 5. Equal-diameter four-way pipe fitting. Specific embodiments

[0021] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the following further details the present utility model through examples and in conjunction with the accompanying drawings. It should be understood that the specific examples described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0022] The following refers to Figure 1 to describe a system for online switching of different medium gases in a solid oxide fuel cell system provided by an embodiment of the present application.

[0023] A system for online switching of different medium gases in a solid oxide fuel cell system includes a nitrogen gas pipeline 1, a hydrogen gas pipeline 2, a nitrogen-hydrogen mixed gas pipeline 3 and an anode main pipeline 4. The anode main pipeline 4 is respectively connected to the nitrogen gas pipeline 1, the hydrogen gas pipeline 2 and the nitrogen-hydrogen mixed gas pipeline 3 through an equal-diameter four-way pipe fitting 5;

[0024] The nitrogen gas pipeline 1 includes a nitrogen gas cylinder 101, and the outlet end of the nitrogen gas cylinder 101 is connected with a solenoid valve 102 through a pipeline;

[0025] The hydrogen gas pipeline 2 includes a hydrogen gas cylinder 201, and the outlet end of the hydrogen gas cylinder 201 is connected with a solenoid valve 202 through a pipeline;

[0026] The nitrogen-hydrogen mixed gas pipeline 3 includes a nitrogen-hydrogen mixed gas cylinder 301, and the outlet end of the nitrogen-hydrogen mixed gas cylinder 301 is connected with a solenoid valve 302 through a pipeline;

[0027] The anode main pipeline 4 includes a solenoid valve 401, a mass flow controller 402, a reformer 403 and an SOFC stack 404 connected in sequence. The mass flow controller 402 can control the flow rate of the gas flowing through the pipeline.

[0028] Furthermore, the inlet end of the solenoid valve 401 is connected with the outlet end of the equal-diameter four-way pipe fitting 5 through a pipeline.

[0029] In a further embodiment, the outlet ends of the solenoid valve 102, the solenoid valve 202 and the solenoid valve 302 are respectively connected with the inlet end of the equal-diameter four-way pipe fitting 5 through pipelines.

[0030] Solid oxide fuel cells belong to the third generation of fuel cells and are all-solid-state chemical power generation devices that directly and efficiently convert the chemical energy stored in fuels and oxidants into electrical energy in an environmentally friendly manner at medium and high temperatures.

[0031] Anode: In a fuel cell, under the driving force of oxygen concentration difference, oxygen ions are transferred directionally through oxygen vacancies in the electrolyte and migrate to the anode to react with the fuel. For example, hydrogen and oxygen ions react to form water vapor and electrons under the action of the anode catalyst. The electrons released by the anode reaction flow back to the cathode through the external circuit. Cathode: In a fuel cell, on the porous cathode, oxygen molecules obtain electrons from the external circuit and are reduced to oxygen ions.

[0032] Combined with the above embodiments, the working principle and specific working process of a system for online switching of different medium gases in a solid oxide fuel cell system of the present application will be described: During the operation of a solid oxide fuel cell (SOFC), it needs to go through five stages: anode circuit airtightness, anode circuit purging, initial heating and temperature rise, stack temperature rise and reduction, and stack power generation and output.

[0033] Anode circuit airtightness: Nitrogen is introduced into the anode pipeline of the SOFC, and the airtightness of the anode pipeline is tested by the pressure drop method.

[0034] Anode circuit purging: Nitrogen is introduced into the anode pipeline of the SOFC, and the fuel gas in the anode pipeline is replaced by nitrogen purging.

[0035] Initial heating and temperature rise: A nitrogen-hydrogen mixture (5% H2-mol) is introduced into the anode pipeline of the SOFC to heat and raise the temperature of the stack.

[0036] Stack temperature rise and reduction: Hydrogen is introduced into the anode pipeline of the SOFC system, and the catalyst on the anode surface of the stack is reduced by hydrogen, making the stack more active, accelerating the reaction rate, and improving the output performance of the stack.

[0037] Stack power generation and output: When the stack has completed temperature rise and reduction, fuel gas can be introduced to carry the load and generate power output.

[0038] Specifically, it includes the following working process:

[0039] Step 1: When an anode circuit airtightness test is required, open the nitrogen cylinder 101, open the solenoid valve 102, and open the solenoid valve 401. The hydrogen pipeline 2 and the nitrogen-hydrogen mixture pipeline 3 are closed, so that nitrogen can be introduced into the anode main pipeline 4 of the SOFC for airtightness pressure holding; when other gases need to be switched, only open the solenoid valve corresponding to the response gas, and the normal operation of the SOFC system is not affected during the online switching process.

[0040] Step 2: After the anode airtightness test is completed, purge the anode main pipeline 4 with nitrogen to displace the fuel gas in the anode main pipeline 4. When switching to other gases, only open the solenoid valve of the corresponding gas, and the normal operation of the SOFC system will not be affected during the online switching process.

[0041] Step 3: After the anode pipeline purge test is completed, the nitrogen-hydrogen mixed gas cylinder 301 can be opened first, the solenoid valve three 302 can be opened, and then the solenoid valve one 102 can be closed, so that the online switching of nitrogen to nitrogen-hydrogen mixed gas is realized. The anode main pipeline 4 is filled with nitrogen-hydrogen mixed gas, and the stack can be heated up.

[0042] Step 4: After the stack heating-up test is completed, open the hydrogen cylinder 201, open the solenoid valve two 202, and then close the solenoid valve three 302, so that the online switching of nitrogen-hydrogen mixed gas to hydrogen is realized. The anode main pipeline 4 is filled with hydrogen, and the stack can be heated up and reduced.

[0043] Step 5: After the stack heating-up and reduction test is completed, hydrogen can continue to be supplied to generate power output of the stack. When switching to other gases, only open the solenoid valve of the corresponding gas, and the normal operation of the SOFC system will not be affected during the online switching process.

[0044] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0045] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A system for online switching of different medium gases in a solid oxide fuel cell system, comprising a nitrogen gas pipeline (1), a hydrogen gas pipeline (2), a nitrogen-hydrogen mixed gas pipeline (3), and an anode main pipeline (4), characterized in that: The total anode pipeline (4) is connected to the nitrogen pipeline (1), the hydrogen pipeline (2), and the nitrogen-hydrogen mixed gas pipeline (3) respectively through an equal-diameter four-way pipe fitting (5); The nitrogen pipeline (1) includes a nitrogen gas cylinder (101), and the outlet end of the nitrogen gas cylinder (101) is connected with a solenoid valve I (102) through a pipeline; The hydrogen pipeline (2) includes a hydrogen gas cylinder (201), and the outlet end of the hydrogen gas cylinder (201) is connected with a solenoid valve II (202) through a pipeline; The nitrogen-hydrogen mixed gas pipeline (3) includes a nitrogen-hydrogen mixed gas cylinder (301), and the outlet end of the nitrogen-hydrogen mixed gas cylinder (301) is connected with a solenoid valve III (302) through a pipeline; The total anode pipeline (4) includes a solenoid valve IV (401), a mass flow controller (402), a reformer (403), and a SOFC stack (404) connected in sequence; 2. The system for online switching of different medium gases in a solid oxide fuel cell system according to claim 1, characterized in that: The inlet end of the solenoid valve IV (401) is connected with the outlet end of the equal-diameter four-way pipe fitting (5) through a pipeline; 3. The system for online switching of different medium gases in a solid oxide fuel cell system according to claim 1, wherein: The outlet ends of the solenoid valve I (102), the solenoid valve II (202), and the solenoid valve III (302) are respectively connected with the inlet end of the equal-diameter four-way pipe fitting (5) through pipelines;

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