A self-heat storage tubular SOFC power supply device for methane fuel and working method

Abstract

The present invention discloses a methane fuel self-heat storage tubular SOFC power supply device and a working method, the device comprises a fuel tank filled with methane, a water bath heating chamber provided with a water bath heating system, a gas splitter screen, a tubular solid oxide fuel cell stack, heat storage ceramics a and b for collecting tail gas heat, and a tail gas collection device. The device converts the chemical energy of methane into electrical energy, improves power generation efficiency, does not produce harmful pollutants such as nitrogen oxides, and has low working noise; no external thermocouple device is required to maintain the working temperature of the tubular solid oxide fuel cell, reducing the production cost and volume weight of the device; the heat of the tail gas is collected by two heat storage ceramics to achieve efficient heat recovery and utilization; at the same time, the explosion risk of the tubular solid oxide fuel cell is avoided, and the effects of anti-carbon deposition and long-term stable operation can be effectively achieved, and it is a safe, reliable, stable, efficient, portable and environmentally friendly small power source for fuel.

Description

Technical Field

[0001] The invention relates to the technical field of methane utilization, and in particular to a methane fuel self-heat storage tubular SOFC power supply device and a working method. Background Art

[0002] Solid oxide fuel cells (SOFCs) are small power sources with high energy density. Compared with lithium batteries and zinc batteries, SOFCs are smaller in size and lighter in weight when obtaining the same amount of electricity, and can generate electricity at any time. They are a recognized green energy source. In addition, solid oxide fuel cells do not require precious metals as catalysts and have advantages such as no penetration corrosion. my country has abundant natural gas reserves, and natural gas has the advantages of being economical, clean, and efficient. Its main component is methane. The products of methane combustion are only water and carbon dioxide. It is a high-quality energy source that is close to environmental protection and easy to store and transport. Using methane as fuel is of great significance for reducing consumption and reducing the greenhouse effect.

[0003] In view of the current situation of low energy density, short life and environmental pollution of lithium-ion batteries and zinc batteries, as well as the problems of carbon deposition and thermal stress, poor inner anode current collection efficiency, complex sealing, uneven working conditions of single cell tubes in the battery stack, and waste of exhaust heat in traditional tubular batteries in the field of solid oxide fuel cells, there is an urgent need to make systematic improvements to tubular solid oxide fuel cells. Summary of the invention

[0004] One of the purposes of the present invention is to provide a methane fuel self-heat storage tubular SOFC power supply device, which can convert the chemical energy in methane into electrical energy, reduce resource waste, and at the same time be resistant to carbon deposition and thermal stress to achieve higher energy and efficiency.

[0005] A second object of the present invention is to provide a working method for the self-heat storage tubular SOFC power supply device using methane fuel.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] On the one hand, the present invention provides a self-heat storage tubular SOFC power supply device for methane fuel, which includes a fuel tank filled with methane, a water bath heating chamber equipped with a water bath heating system, a gas diversion screen, a tubular solid oxide fuel cell stack, heat storage ceramic a and heat storage ceramic b for collecting exhaust gas heat, and an exhaust gas collecting device, wherein the fuel tank is connected to the water bath heating chamber through an air path, the water bath heating chamber is connected to the gas diversion screen through an air path, the gas diversion screen is connected to the inlet of the tubular solid oxide fuel cell stack and enters the anode gas channel of the battery stack, the heat storage ceramic a and the heat storage ceramic b are respectively connected to the cathode gas channel of the tubular solid oxide fuel cell stack through pipelines, the outlet of the tubular solid oxide fuel cell stack is connected to the exhaust gas collecting device, the exhaust gas collecting device is connected to the heat storage ceramic a and the heat storage ceramic b, and the tubular solid oxide fuel cell stack outputs direct current to the outside.

[0008] Preferably, the battery stack is composed of 5-10 tubular solid oxide fuel cell monomers connected in parallel.

[0009] Preferably, the supporting anode of the solid oxide fuel cell monomer is NiO-YSZ with a thickness of 500-2000 μm; the electrolyte is YSZ with a thickness of 10-20 μm; the cathode is LSCF-GDC with a thickness of 40-50 μm; the battery length is ≥100 mm and the outer diameter is ≥8 mm.

[0010] Preferably, the sieve channels of the gas splitter sieve match the number of battery cells in the tubular solid oxide fuel cell stack.

[0011] Preferably, control valves are respectively provided on the pipelines connecting the tail gas collection device and the heat storage ceramic a and the heat storage ceramic b.

[0012] On the other hand, the present invention also provides a method for operating a methane fuel self-heat storage tubular SOFC power supply device, comprising the following steps:

[0013] S1, directly introducing methane into the thermal storage ceramic a and the thermal storage ceramic b, igniting the methane in the two thermal storage ceramics respectively, thereby raising the temperature of the thermal storage ceramic a and the thermal storage ceramic b to 900°C-1000°C, raising the temperature of the tubular solid oxide fuel cell stack to 650°C-800°C, and then stopping directly introducing methane into the two thermal storage ceramics;

[0014] S2, the methane in the fuel tank enters the water bath heating chamber through the gas path, and after being heated in the water bath, a mixed fuel gas of methane and water vapor is obtained;

[0015] S3, the mixed fuel gas enters the gas splitter screen through the gas path, and then is evenly divided into several streams of the same fuel gas, which enter the battery cells respectively to ensure the uniform working condition of each battery cell. The mixed fuel then enters the anode gas channel of the tubular solid oxide fuel cell stack, participates in the electrochemical reaction, and the stack outputs direct current to the outside;

[0016] S4. After the electrochemical reaction, the high-temperature anode tail gas with a small amount of residual combustible gas enters the tail gas collection device, and then mixes with the outside air and enters the thermal storage ceramic a. The mixed gas is heated to 650℃-800℃ in the thermal storage ceramic a, and then enters the cathode gas channel of the battery stack;

[0017] S5. The combustible gas in the mixed gas undergoes an oxidation reaction with the air at high temperature under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the tubular solid oxide fuel cell stack. The air flows out of the cathode airway and enters the heat storage ceramic b, and the temperature of the heat storage ceramic b rises.

[0018] S6. When the temperature of the thermal storage ceramic a is lower than the required operating temperature of the tubular solid oxide fuel cell stack, the exhaust gas and air in the exhaust gas collection device are mixed and enter the thermal storage ceramic b by controlling the valve. The mixed gas is heated to 650°C-800°C by the thermal storage ceramic b and then enters the cathode gas channel of the tubular solid oxide fuel cell stack;

[0019] S7, the combustible gas in the mixed gas undergoes an oxidation reaction with the air at high temperature under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the tubular solid oxide fuel cell stack, and the air flows out of the cathode airway and enters the heat storage ceramic a, and the temperature of the heat storage ceramic a rises;

[0020] S8, the cycle is repeated to realize the round-trip utilization of heat.

[0021] Preferably, the water-to-carbon ratio of the mixed gas consisting of methane and water vapor is limited to between 3 and 6.

[0022] On the one hand, the present invention heat-treats methane and water by heating in a water bath, and then evenly divides them into several identical fuel gases by a gas splitter screen, and enters the anode gas channel of the tubular solid oxide fuel cell to participate in the electrochemical reaction. Air enters the cathode of the solid oxide fuel cell to participate in the electrochemical reaction, and the tubular solid oxide fuel cell outputs direct current to the outside world. On the other hand, the collection of tail gas by two heat storage ceramics realizes efficient energy recovery and utilization. Compared with the prior art, the present invention has the following advantages:

[0023] (1) The present invention directly converts the chemical energy of methane into electrical energy, is not limited by the Carnot cycle efficiency, has high power generation efficiency, and the obtained tail gas is H 2 O and CO 2 , almost pollution-free, can alleviate the greenhouse effect;

[0024] (2) In the present invention, the two-way flow of gas is achieved by controlling the valve, so that the two heat storage ceramics can recycle the exhaust energy of the solid oxide fuel cell in turn, without using an external power supply, reducing system complexity, lowering costs, and facilitating the integration of a battery stack with a higher power density.

[0025] (3) The tubular solid oxide fuel cell of the present invention has a fast temperature rise, a fast startup speed, good thermal stability in temperature rise and fall, and is easy to seal. A single solid oxide fuel cell tube is sealed into a small fuel cell stack, thereby realizing the portable mobility of a "small power station".

[0026] (4) In the present invention, CH 4 Using direct internal reforming, the reforming reaction includes:

[0027] CH 4 +H 2 O→CO+H 2

[0028] CO+H 2 O→CO 2 +H 2

[0029] CH 4 Mixed with water vapor, the water-to-carbon ratio is limited to 3-6, and the mixed gas completes the reforming reaction at the anode and realizes H 2 The reduction process of CH 4 The chemical energy of the fuel cell is converted into electrical energy. Since the reforming reaction takes place inside the fuel cell stack, the heat of the fuel cell stack itself can be used to complete the reforming, thereby improving fuel utilization and power generation efficiency.

[0030] (5) The present invention increases the voltage by connecting the single cell tubes in parallel. A pair of multi-gas diffusion splitter screens are installed in front of the fuel inlet of the battery stack. The fuel gas enters the splitter screen and is then evenly divided into 10 streams of the same fuel gas flow, which enter the single cell tubes respectively, to ensure that the working condition of each single cell tube is uniform.

[0031] (6) In the present invention, when the electrolyte and cathode slurry are spin-coated, 1 / 5 of the anode support is left vacant so that it is exposed outside the battery tube. When current collection is performed, the silver wire only needs to be completely wrapped around the outside of the battery, making current collection more convenient and more efficient, and the battery sealing effect is simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a system device diagram of the present invention;

[0033] In the figure: 1. fuel tank; 2. water bath heating chamber; 3. gas diversion screen; 4. tubular solid oxide fuel cell stack; 5. heat storage ceramic a; 6. heat storage ceramic b; 7. exhaust gas collection device. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0035] The present invention provides a methane fuel self-heat storage tubular SOFC power supply device, such as Figure 1 As shown, the device includes a fuel tank 1 filled with methane, a water bath heating chamber 2 provided with a water bath heating system, a gas diversion screen 3, a tubular solid oxide fuel cell stack 4, heat storage ceramics a5 and heat storage ceramics b6 for collecting exhaust gas heat, and an exhaust gas collecting device 7. The fuel tank 1 is connected to the water bath heating chamber 2 through an air path, the water bath heating chamber 2 is connected to the inlet of the gas diversion screen 3 through the air path, the outlet of the gas diversion screen 3 is connected to the anode gas channel of the tubular solid oxide fuel cell stack 4, the heat storage ceramics a5 and the heat storage ceramics b6 are respectively connected to the cathode gas channel of the tubular solid oxide fuel cell stack 4 through pipelines, the outlet of the tubular solid oxide fuel cell stack 4 is connected to the exhaust gas collecting device 7, the exhaust gas collecting device 7 is respectively connected to the heat storage ceramics a5 and the heat storage ceramics b6, and the tubular solid oxide fuel cell stack 4 outputs direct current to the outside.

[0036] In one of the preferred embodiments of the present invention, the tubular solid oxide fuel cell stack 4 is composed of 5 to 10 tubular solid oxide fuel cell monomers connected in parallel.

[0037] In order to meet the requirements of rapid start-up of portable small power sources, ensure a certain resistance to mechanical stress and thermal stress, and be able to better parallelize to form a large-scale battery stack to achieve a practical size, the supporting anode of the solid oxide fuel cell monomer adopts NiO-YSZ, and the supporting anode layer thickness is 500-2000μm; the electrolyte is YSZ, with a thickness of 10-20μm; the cathode is LSCF-GDC, with a thickness of 40-50μm; the battery length is ≥100mm, and the outer diameter is ≥8mm.

[0038] In order to achieve higher current collection efficiency, the traditional method of collecting current on the anode on the inside of the tubular battery is changed. When spin-coating the electrolyte and cathode slurry, 1 / 5 of the anode support is left empty to expose it to the outside of the single cell tube. When collecting current, the silver wire only needs to be wrapped around the outside of the battery.

[0039] In order to ensure that the tubular solid oxide fuel cell has a higher power generation capacity, does not affect the long-term stability of the battery operation, and reduces the performance requirements of the fuel cell stack materials, the operating temperature of the tubular solid oxide fuel cell stack 4 is 650°C to 800°C.

[0040] In order to control the flow direction of the gas, control valves are respectively provided on the pipelines connecting the tail gas collection device 7 and the heat storage ceramics a5 and b6.

[0041] The present invention also provides a working method of a methane fuel self-heat storage tubular SOFC power supply device, which includes two aspects: on the one hand, the fuel gas obtained by mixing methane and water vapor is evenly divided into several bundles of the same fuel gas through a gas splitter screen 3, and the fuel gas flows into the anode gas channel of the tubular solid oxide fuel cell stack 4 to participate in the electrochemical reaction, and the air flows into the cathode gas channel of the solid oxide fuel cell stack 4 through the heat storage ceramic a5 or the heat storage ceramic b6 to participate in the electrochemical reaction, and at the same time, the tubular solid oxide fuel cell stack 4 outputs direct current to the outside to realize the conversion of chemical energy into electrical energy;

[0042] On the other hand, the solid oxide fuel cell stack 4 releases high-heat exhaust gas when working, and the exhaust gas collection device 7 first transfers the anode exhaust gas to the heat storage ceramic a5 to maintain the temperature of the heat storage ceramic a5. At the same time, the combustible gas contained in the exhaust gas undergoes an oxidation reaction with the air in the high-temperature chamber containing the cathode under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the solid oxide fuel cell stack 4.

[0043] After a certain discharge working time, the temperature of the heat storage ceramic a5 is lower than the SOFC operating temperature. At this time, the valve is switched, and the exhaust gas collection device 7 transfers the exhaust gas to the heat storage ceramic b6. The air enters the cathode gas channel of the SOFC battery stack through the heat storage ceramic b6 that absorbs enough heat, and heats the heat storage ceramic a5 after being discharged. When the temperature of the heat storage ceramic b6 is lower than the SOFC operating temperature, the mixture of the anode exhaust gas and the air passes through the heat storage ceramic a5 and then enters the cathode gas channel of the battery stack, and heats the heat storage ceramic b6 after being discharged. This cycle is repeated to realize the round-trip utilization of heat.

[0044] The specific steps are as follows:

[0045] S1, directly introducing methane into the thermal storage ceramic a5 and the thermal storage ceramic b6, igniting the methane in the two thermal storage ceramics respectively, thereby raising the temperature of the thermal storage ceramic a5 and the thermal storage ceramic b6 to 900°C-1000°C, raising the temperature of the tubular solid oxide fuel cell stack 4 to 650°C-800°C, and then stopping directly introducing methane into the two thermal storage ceramics;

[0046] S2, the methane in the fuel tank enters the water bath heating chamber 2 through the gas path, and after being heated in the water bath, a mixed fuel gas of methane and water vapor is obtained;

[0047] S3, the mixed fuel gas enters the gas splitter screen 3 through the gas path, and then is evenly divided into several streams of the same fuel gas flow, which enter the battery cells respectively to ensure the uniform working condition of each battery cell; the mixed fuel enters the anode gas channel of the tubular solid oxide fuel cell stack 4, participates in the electrochemical reaction, and the stack outputs direct current to the outside;

[0048] S4, after the electrochemical reaction, the high-temperature anode tail gas with a small amount of residual combustible gas enters the tail gas collection device 7, and then mixes with the outside air and enters the heat storage ceramic a5. The mixed gas is heated to 650℃-800℃ in the heat storage ceramic a5, and then enters the cathode gas channel of the battery stack;

[0049] S5, the combustible gas in the mixed gas undergoes an oxidation reaction with the air at high temperature under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the tubular solid oxide fuel cell stack 4, and the air flows out of the cathode airway and enters the heat storage ceramic b6, and the temperature of the heat storage ceramic b6 increases;

[0050] S6, when the temperature of the thermal storage ceramic a5 is lower than the required operating temperature of the SOFC, the exhaust gas and air in the exhaust gas collection device are mixed and enter the thermal storage ceramic b6 by controlling the valve. The mixed gas is heated to 650℃-800℃ by the thermal storage ceramic b6 and then enters the cathode gas channel of the SOFC battery stack;

[0051] S7. The combustible gas in the mixed gas undergoes an oxidation reaction with the air at high temperature under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the tubular solid oxide fuel cell stack 4. The air flows out of the cathode airway and enters the heat storage ceramic a5, and the temperature of the heat storage ceramic a5 increases.

[0052] S8, the cycle is repeated to realize the round-trip utilization of heat.

[0053] In order to reduce carbon deposits generated by internal reforming of methane, the water-to-carbon ratio of the gas after the methane and water are mixed is limited to 3-6.

[0054] In order to realize the recycling of its own heat and improve the overall utilization efficiency of the fuel, the flow direction of the gas is controlled by two control valves, and the exhaust gas energy is collected and stored by an exhaust gas collection device and two heat storage ceramics, thereby realizing the recycling of energy. The temperature of the heat storage ceramics is maintained between 900℃ and 1000℃.

Claims

1. A methane fuel self-heat storage tubular SOFC power supply device, It is characterized in that The device comprises a fuel tank (1) containing methane, a water bath heating chamber (2) provided with a water bath heating system, a gas diversion screen (3), a tubular solid oxide fuel cell stack (4), heat storage ceramics a (5) and heat storage ceramics b (6) for collecting tail gas heat, and a tail gas collection device (7). The fuel tank (1) is connected to the water bath heating chamber (2) through a gas path, the water bath heating chamber (2) is connected to the gas diversion screen (3) through a gas path, the gas diversion screen (3) is connected to the anode gas channel of the tubular solid oxide fuel cell stack (4), the heat storage ceramics a (5) and the heat storage ceramics b (6) are respectively connected to the cathode gas channel of the tubular solid oxide fuel cell stack (4) through pipelines, the outlet of the tubular solid oxide fuel cell stack (4) is connected to the tail gas collection device (7), the tail gas collection device (7) is respectively connected to the heat storage ceramics a (5) and the heat storage ceramics b (6), and the tubular solid oxide fuel cell stack (4) outputs direct current to the outside.

2. A methane fuel self-heat storage tubular SOFC power supply device according to claim 1, It is characterized in that The tubular solid oxide fuel cell stack (4) is composed of 5 to 10 tubular solid oxide fuel cell monomers connected in parallel.

3. The methane fuel self-heat storage tubular SOFC power supply device according to claim 2, It is characterized in that The supporting anode of the solid oxide fuel cell monomer is NiO-YSZ with a thickness of 500-2000 μm; the electrolyte is YSZ with a thickness of 10-20 μm; The cathode is LSCF-GDC with a thickness of 40-50 μm; the battery length is ≥100 mm and the outer diameter is ≥8 mm.

4. The methane fuel self-heat storage tubular SOFC power supply device according to claim 1, It is characterized in that The sieve channels of the gas splitter sieve (3) match the number of battery cells in the tubular solid oxide fuel cell stack (4).

5. The methane fuel self-heat storage tubular SOFC power supply device according to claim 1, It is characterized in that Control valves are respectively provided on the pipelines connecting the tail gas collection device (7) and the heat storage ceramic a (5) and the heat storage ceramic b (6).

6. A method for operating the methane fuel self-heat storage tubular SOFC power supply device according to any one of claims 1 to 5, It is characterized in that The following steps are involved: S1, directly introducing methane into the thermal storage ceramic a (5) and the thermal storage ceramic b (6), igniting the methane in the two thermal storage ceramics respectively, thereby raising the temperature of the thermal storage ceramic a (5) and the thermal storage ceramic b (6) to 900° C.-1000° C., raising the temperature of the tubular solid oxide fuel cell stack (4) to 650° C.-800° C., and then stopping directly introducing methane into the two thermal storage ceramics; S2, the methane in the fuel tank (1) enters the water bath heating chamber (2) through the gas path, and after being heated in the water bath, a mixed fuel gas of methane and water vapor is obtained; S3, the mixed fuel gas enters the gas splitter screen (3) through the gas path, and then is evenly divided into several streams of the same fuel gas, which enter the battery cells respectively to ensure the uniform working condition of each battery cell. The mixed fuel then enters the anode gas channel of the tubular solid oxide fuel cell stack (4), participates in the electrochemical reaction, and the stack outputs direct current to the outside; S4, after the electrochemical reaction, the anode tail gas with high temperature and a small amount of residual combustible gas enters the tail gas collection device (7), and then mixes with the outside air and enters the heat storage ceramic a (5). The mixed gas is heated to 650°C-800°C in the heat storage ceramic a (5), and then enters the cathode gas channel of the tubular solid oxide fuel cell stack (4); S5, the combustible gas in the mixed gas undergoes an oxidation reaction with the air at high temperature under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the tubular solid oxide fuel cell stack (4), and the air flows out of the cathode air channel and enters the heat storage ceramic b (6), and the temperature of the heat storage ceramic b (6) increases; S6. When the temperature of the heat storage ceramic a (5) is lower than the required operating temperature of the tubular solid oxide fuel cell stack (4), the exhaust gas and air in the exhaust gas collection device (7) are mixed and enter the heat storage ceramic b (6) by controlling the valve. The mixed gas is heated to 650° C.-800° C. by the heat storage ceramic b (6) and then enters the cathode gas channel of the tubular solid oxide fuel cell stack (4); S7, the combustible gas in the mixed gas undergoes an oxidation reaction with the air at high temperature under the catalytic action of the battery cathode material, releasing heat to maintain the temperature of the tubular solid oxide fuel cell stack (4), and the air flows out of the cathode air channel and enters the heat storage ceramic a (5), and the temperature of the heat storage ceramic a (5) increases; S8, the cycle is repeated to realize the round-trip utilization of heat.

7. The method for operating the methane fuel self-heat storage tubular SOFC power supply device according to claim 6, It is characterized in that The water-to-carbon ratio of the mixed fuel gas is limited to 3-6.

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