Fuel cell power generation system

Abstract

The invention discloses a fuel cell power generation system, comprising: a solid oxide fuel cell stack: using hot hydrogen and hot air as raw materials for electrochemical power generation, a burner: connected to the solid oxide fuel cell stack, and burning the tail gas generated by the reaction of the solid oxide fuel cell stack, a first heat exchanger: connected to the solid oxide fuel cell stack and the burner respectively, a reformer: connected to the first heat exchanger, methanol is decomposed through the reformer to generate hydrogen and introduced into the first heat exchanger, a second heat exchanger: connected to the first heat exchanger and the reformer respectively, and the remaining heat after heating the hydrogen and air in the first heat exchanger is used to provide heat for the decomposition reaction in the reformer. Compared with the prior art, the invention reasonably utilizes the various levels of heat energy generated by the tail gas, improves the utilization rate of the tail gas, reduces the input end pressure and back pressure, accelerates the overall startup rate of the system, and effectively prolongs the battery life.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation equipment, and in particular to a fuel cell power generation system. Background Art

[0002] Solid oxide fuel cells (SOFCs) have no combustion process, which greatly reduces fuel energy loss and atmospheric pollutant emissions. Therefore, they have advantages that traditional power generation devices do not have, and have broad application prospects in portable power generation devices, automotive auxiliary power supplies, and distributed power stations.

[0003] SOFC has a high energy conversion efficiency and can achieve an electrical conversion efficiency of more than 50%. The quality of waste heat is very high and can be used in conjunction with gas turbines or steam engines, so that the comprehensive utilization rate of fuel reaches more than 80%. Under the same electrical load, it is much higher than the electrical efficiency of traditional thermal engine power generation devices (less than or equal to 30%). The operating temperature of SOFC is 650℃ to 850℃, which can avoid the poisoning of CO to the metal ceramic electrode (Ni-YSZ), reducing the requirements of SOFC on fuel quality, so it has strong fuel adaptability and can use hydrogen, hydrocarbon gas, diesel, kerosene, etc. as fuel. Although in theory SOFC can directly use hydrocarbons as fuel for power generation, for the most commonly used Ni-YSZ anode, the carbon deposition and sulfur poisoning on the electrode will cause its catalytic performance to drop sharply. Therefore, hydrocarbon fuels such as methane (CH4) and methanol are generally reformed externally into CO and H2, and then introduced into the anode side of the SOFC stack for power generation, but the above structure still has the disadvantages of low tail gas utilization, complex process, and high back pressure. Summary of the invention

[0004] The purpose of the present invention is to provide a fuel cell power generation system that rationally utilizes the various levels of heat energy generated by exhaust gas, improves exhaust gas utilization, reduces input end air pressure and back pressure, speeds up the overall system startup rate, and effectively prolongs battery life.

[0005] To achieve the above object, the present invention provides a fuel cell power generation system, comprising:

[0006] Solid oxide fuel cell stack: uses hot hydrogen and hot air as raw materials for electrochemical power generation;

[0007] Burner: connected to the solid oxide fuel cell stack to burn the tail gas generated by the reaction of the solid oxide fuel cell stack;

[0008] The first heat exchanger is connected to the solid oxide fuel cell stack and the burner respectively, and uses the hot air flow generated by the burner burning the exhaust gas to heat the hydrogen and air entering the first heat exchanger, and transmits the heated hot hydrogen and hot air to the solid oxide fuel cell stack;

[0009] Reformer: connected to the first heat exchanger, methanol is decomposed by the reformer to generate hydrogen which is then passed into the first heat exchanger;

[0010] The second heat exchanger is connected to the first heat exchanger and the reformer respectively, and uses the remaining heat after heating the hydrogen and air in the first heat exchanger to provide heat for the decomposition reaction in the reformer.

[0011] Preferably, it further comprises a fuel tank, which is connected to the reformer and the burner respectively, and provides the reformer with decomposition products and the burner with combustion raw materials.

[0012] Preferably, the fuel tank is connected to the burner via a first electrically controlled valve, and the fuel tank is connected to the reformer via a second electrically controlled valve. Before the solid oxide fuel cell stack starts working, the first electrically controlled valve and the second electrically controlled valve are both opened, and the fuel in the fuel tank enters the burner and the reformer respectively; after the solid oxide fuel cell stack starts working, the first electrically controlled valve is closed, the second electrically controlled valve is opened, and the fuel in the fuel tank enters the reformer.

[0013] Preferably, a variable flow pump and a pressure sensor are provided at the outlet of the fuel tank.

[0014] Preferably, a flow meter is provided between the fuel tank and the first electrically controlled valve and the second electrically controlled valve.

[0015] Preferably, a heat distribution device is further included, which is respectively connected to the burner, the first heat exchanger and the second heat exchanger, and is used to adjust the distribution of heat generated by the burner combustion exhaust gas between the first heat exchanger and the second heat exchanger.

[0016] Preferably, the heat distribution device includes a fan and a third heat exchanger, and the third heat exchanger is respectively connected to the fan, the burner, the first heat exchanger and the second heat exchanger. When the fan is not working, the heat of the third heat exchanger is transferred to the first heat exchanger to heat the hydrogen and air entering the first heat exchanger; when the fan is turned on, the air enters the third heat exchanger and flows in the direction of the second heat exchanger, and takes away part of the heat in the third heat exchanger and transfers it to the second heat exchanger, and the remaining heat in the third heat exchanger is transferred to the first heat exchanger to heat the hydrogen and air.

[0017] Preferably, the fan and the third heat exchanger are connected via a check valve.

[0018] Preferably, a filter is provided at the inlet of the fan for filtering the incoming air.

[0019] Preferably, the first heat exchanger is selected from one of the following: a plate heat exchanger, a tube heat exchanger, and a floating head heat exchanger.

[0020] Preferably, the second heat exchanger is a plate heat exchanger, and the medium in the second heat exchanger is selected from one of oil, ethylene glycol, and a mixture of water and ethylene glycol.

[0021] Preferably, the third heat exchanger is selected from one of the following: a plate heat exchanger, a tube heat exchanger, and a floating head heat exchanger.

[0022] Preferably, a buffer tank is provided between the reformer and the first heat exchanger, and the buffer tank can be used to temporarily store hydrogen generated by the reformer decomposing the fuel.

[0023] Compared with the prior art, the present invention rationally utilizes various levels of heat energy generated by exhaust gas, improves exhaust gas utilization, reduces input end air pressure and back pressure, accelerates the overall system startup rate, and effectively prolongs battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a fuel cell power generation system in Example 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the fuel cell power generation system in Example 2 of the present invention.

[0026] Description of reference numerals:

[0027] 1-solid oxide fuel cell stack; 2-burner; 3-first heat exchanger; 4-reformer; 41-buffer tank; 5-second heat exchanger; 6-fuel tank; 61-first electric control valve; 62-second electric control valve; 63-variable flow pump; 64-pressure sensor; 65-flow meter; 7-heat distribution device; 71-blower; 72-third heat exchanger; 73-check valve; 74-filter. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] like Figure 1 As shown, a fuel cell power generation system comprises:

[0031] Solid oxide fuel cell stack 1: electrochemical power generation using hot hydrogen and hot air as raw materials;

[0032] Burner 2: connected to the solid oxide fuel cell stack 1, and burns the tail gas generated by the reaction of the solid oxide fuel cell stack 1;

[0033] The first heat exchanger 3 is connected to the solid oxide fuel cell stack 1 and the burner 2 respectively, and uses the hot air flow generated by the burner 2 burning the exhaust gas to heat the hydrogen and air entering the first heat exchanger 3, and transmits the heated hot hydrogen and hot air to the solid oxide fuel cell stack 1;

[0034] Reformer 4: connected to the first heat exchanger 3, methanol is decomposed by the reformer 4 to generate hydrogen which is introduced into the first heat exchanger 3;

[0035] The second heat exchanger 5 is connected to the first heat exchanger 3 and the reformer 4 respectively, and uses the remaining heat after heating the hydrogen and air in the first heat exchanger 3 to provide heat for the decomposition reaction in the reformer 4.

[0036] The first heat exchanger 3 is provided with a low-temperature hydrogen inlet, a low-temperature air inlet, a high-temperature hydrogen outlet, and a high-temperature air outlet, and the low-temperature hydrogen inlet on the first heat exchanger 3 is connected to the hydrogen outlet of the reformer 4, the low-temperature air inlet on the first heat exchanger 3 is connected to the air duct, the high-temperature hydrogen outlet on the first heat exchanger 3 is connected to the anode of the solid oxide fuel cell stack 1, the high-temperature air outlet on the first heat exchanger 3 is connected to the cathode of the solid oxide fuel cell stack 1, and the hot gas inlet of the first heat exchanger 3 is connected to the exhaust gas outlet of the burner 2, and the hot gas outlet of the first heat exchanger 3 is connected to the hot gas inlet of the second heat exchanger 5.

[0037] The second heat exchanger 5 is provided with a hot gas inlet, an exhaust gas outlet, a heat medium outlet, and a cold medium inlet. The hot gas inlet on the second heat exchanger 5 is connected to the hot gas outlet of the first heat exchanger 3, and the exhaust gas outlet on the second heat exchanger 5 is discharged into the outside air. The hot medium outlet and the cold medium inlet on the second heat exchanger 5 are both connected to the reformer 4 to supply the heat required for decomposing the fuel in the reformer 4. The cooled medium returns to the second heat exchanger 5 through the cold medium inlet.

[0038] See also Figure 1The working principle of the fuel cell power generation system of this embodiment is as follows: the solid oxide fuel cell stack 1 uses hot hydrogen and hot air as raw materials to perform electrochemical power generation. At the same time, the tail gas generated by the solid oxide fuel cell stack 1 is burned through the burner 2, and the hot gas flow obtained by the combustion flows into the first heat exchanger 3, wherein the first heat exchanger 3 can use the hot air flow generated by the burner 2 burning the tail gas to heat the hydrogen and air entering the first heat exchanger 3, and transmit the heated hot hydrogen and hot air to the solid oxide fuel cell stack 1. The source of hydrogen in the first heat exchanger 3 is the reformer 4. Methanol is passed into the reformer 4, and the hydrogen obtained after decomposition flows into the first heat exchanger 3. In the first heat exchanger 3, when the heat used to heat the hydrogen and air is excessive, the remaining heat is passed into the second heat exchanger 5. The second heat exchanger 5 is connected to the reformer 4, and the hot air flow is passed through the second heat exchanger 5 to exchange heat with the reformer 4, thereby providing the temperature required for the reformer 4 to decompose methanol and complete the cycle.

[0039] Example 2

[0040] like Figure 2 As shown, the fuel cell power generation system in this embodiment includes:

[0041] Solid oxide fuel cell stack 1: electrochemical power generation using hot hydrogen and hot air as raw materials;

[0042] Burner 2: connected to the solid oxide fuel cell stack 1, and burns the tail gas generated by the reaction of the solid oxide fuel cell stack 1;

[0043] The first heat exchanger 3 is connected to the solid oxide fuel cell stack 1 and the burner 2 respectively, and uses the hot air flow generated by the burner 2 burning the exhaust gas to heat the hydrogen and air entering the first heat exchanger 3, and transmits the heated hot hydrogen and hot air to the solid oxide fuel cell stack 1;

[0044] Reformer 4: connected to the first heat exchanger 3, methanol is decomposed by the reformer 4 to generate hydrogen which is introduced into the first heat exchanger 3;

[0045] The second heat exchanger 5 is connected to the first heat exchanger 3 and the reformer 4 respectively, and uses the remaining heat after heating the hydrogen and air in the first heat exchanger 3 to provide heat for the decomposition reaction in the reformer 4;

[0046] The fuel tank 6 is connected to the reformer 4 and the burner 2 respectively, and provides the reformer 4 with decomposition products and the burner 2 with combustion raw materials.

[0047] The heat distribution device 7 includes a fan 71 and a third heat exchanger 72. The third heat exchanger 72 is connected to the fan 71, the burner 2, the first heat exchanger 3 and the second heat exchanger 5 respectively. When the fan 71 is not working, the heat of the third heat exchanger 72 is transmitted to the first heat exchanger 3 to heat the hydrogen and air entering the first heat exchanger 3; when the fan 71 is turned on, the air enters the third heat exchanger 72 and flows toward the second heat exchanger 5, and takes away part of the heat in the third heat exchanger 72 and transmits it to the second heat exchanger 5, and the remaining heat in the third heat exchanger 72 is transmitted to the first heat exchanger 3 to heat the hydrogen and air.

[0048] The third heat exchanger 72 is provided with a hot gas inlet, a hot gas outlet, a hot air outlet and a cold air inlet. The hot gas inlet on the third heat exchanger 72 is connected to the exhaust gas outlet of the burner 2, the hot gas outlet on the third heat exchanger 72 is connected to the first heat exchanger 3, the hot air outlet on the third heat exchanger 72 is connected to the second heat exchanger 5, and the cold air inlet on the third heat exchanger 72 is connected to the outlet of the fan 71.

[0049] The first heat exchanger 3 is provided with a low-temperature hydrogen inlet, a low-temperature air inlet, a high-temperature hydrogen outlet, and a high-temperature air outlet, and the low-temperature hydrogen inlet on the first heat exchanger 3 is connected to the hydrogen outlet of the reformer 4, the low-temperature air inlet on the first heat exchanger 3 is connected to the air duct, the high-temperature hydrogen outlet on the first heat exchanger 3 is connected to the anode of the solid oxide fuel cell stack 1, the high-temperature air outlet on the first heat exchanger 3 is connected to the cathode of the solid oxide fuel cell stack 1, and the hot gas inlet of the first heat exchanger 3 is connected to the exhaust gas outlet of the third heat exchanger 72, and the hot gas outlet of the first heat exchanger 3 is connected to the hot gas inlet of the second heat exchanger 5.

[0050] The second heat exchanger 5 is provided with a hot air inlet, a hot gas inlet, an exhaust gas outlet, a hot medium outlet, and a cold medium inlet, wherein the hot air inlet on the second heat exchanger 5 is connected to the hot air outlet of the third heat exchanger 72, the hot gas inlet on the second heat exchanger 5 is connected to the hot gas outlet of the first heat exchanger 3, the exhaust gas outlet on the second heat exchanger 5 is discharged into the external air, the hot medium outlet and the cold medium inlet on the second heat exchanger 5 are both connected to the reformer 4, for supplying the heat required for decomposing the fuel in the reformer 4, and the cooled medium returns to the second heat exchanger 5 through the cold medium inlet on the second heat exchanger 5.

[0051] In this embodiment, the fuel tank 6 is connected to the burner 2 through the first electrically controlled valve 61, and the fuel tank 6 is connected to the reformer 4 through the second electrically controlled valve 62. Before the solid oxide fuel cell stack 1 starts working, the first electrically controlled valve 61 and the second electrically controlled valve 62 are both opened, and the fuel in the fuel tank 6 enters the burner 2 and the reformer 4 respectively; when the solid oxide fuel cell stack 1 starts working, the first electrically controlled valve 61 is closed, the second electrically controlled valve 62 is opened, and the fuel in the fuel tank 6 enters the reformer 4.

[0052] In this embodiment, the fan 71 and the third heat exchanger 72 are connected via a check valve 73 .

[0053] In this embodiment, the first heat exchanger 3 is a plate heat exchanger, the second heat exchanger 5 is a plate heat exchanger, and the medium in the second heat exchanger 5 is selected from oil, and the third heat exchanger 72 is a tube heat exchanger.

[0054] In this embodiment, a filter 74 is provided at the inlet of the fan 71 .

[0055] In this embodiment, a variable flow pump 63 and a pressure sensor 64 are provided at the outlet of the fuel tank 6 .

[0056] In this embodiment, a flow meter 65 is provided between the fuel tank 6 and the first electrically controlled valve 61 and the second electrically controlled valve 62 , and a buffer tank 41 is provided between the reformer 4 and the first heat exchanger 3 .

[0057] See also Figure 2 The working principle of the fuel cell power generation system of this embodiment is as follows: before the solid oxide fuel cell stack 1 does not work normally, the first electrically controlled valve 61 and the second electrically controlled valve 62 are both opened, and the fuel in the fuel tank 6 enters the burner 2 and the reformer 4 respectively. The fuel entering the burner 2 burns and releases heat in the burner 2, and the hot air flow generated by the fuel combustion is transmitted to the first heat exchanger 3 through the third heat exchanger 72. At this time, the fuel in the fuel tank 6 enters the reformer 4, and the hydrogen obtained by the decomposition of the fuel by the reformer 4 is also passed into the first heat exchanger 3. After the hydrogen and air are heated by the first heat exchanger 3, the hot air and the hot hydrogen are transmitted to the solid oxide fuel cell stack 1. At this time, the solid oxide fuel cell stack 1 works normally, the second electrically controlled valve 62 is opened, and the first electrically controlled valve 61 is closed. The fuel in the fuel tank 6 no longer enters the burner 2, and the tail gas generated after the electrochemical power generation of the solid oxide fuel cell stack 1 is passed into the burner 2, and the burner 2 obtains heat by burning the tail gas.

[0058] The heat first passes through the third heat exchanger 72 and then enters the first heat exchanger 3, wherein the first heat exchanger 3 can utilize the hot air flow generated by the burner 2 burning the exhaust gas to heat the hydrogen and air entering the first heat exchanger 3, and transmit the heated hot hydrogen and hot air to the solid oxide fuel cell stack 1 to form a cycle; when the heat introduced into the first heat exchanger 3 is sufficient to maintain the heat required for heating the hydrogen and air, the fan 71 and the check valve 73 are opened to allow air to flow into the third heat exchanger 72, and the air enters the third heat exchanger 72 and flows in the direction of the second heat exchanger 5, and takes away part of the heat in the third heat exchanger 72 and transmits it to the second heat exchanger 5, and the remaining heat in the third heat exchanger 72 is transmitted to the first heat exchanger 3 to heat the hydrogen and air. Therefore, the inventor can accurately adjust the proportional distribution of heat between the first heat exchanger 3 and the second heat exchanger 5 by adjusting the incoming air flow rate, and the heat obtained by the second heat exchanger 5 is exchanged with the reformer 4, thereby providing the temperature required for the reformer to decompose methanol 4, and completing the cycle.

[0059] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A fuel cell power generation system, characterized in that: The invention comprises a solid oxide fuel cell stack (1) which uses hot hydrogen and hot air as raw materials to perform electrochemical power generation; a burner (2) which is connected to the solid oxide fuel cell stack (1) and burns the tail gas generated by the reaction of the solid oxide fuel cell stack (1); a first heat exchanger (3) which is respectively connected to the solid oxide fuel cell stack (1) and the burner (2) and uses the hot air flow generated by the burner (2) burning the tail gas to heat the hydrogen and air entering the first heat exchanger (3), and heats the heated air to generate a hot gas. Hydrogen and hot air are transmitted to the solid oxide fuel cell stack (1); the reformer (4) is connected to the first heat exchanger (3), and methanol is decomposed through the reformer (4) to generate hydrogen and then introduced into the first heat exchanger (3); the second heat exchanger (5) is respectively connected to the first heat exchanger (3) and the reformer (4), and the remaining heat after heating the hydrogen and air in the first heat exchanger (3) is used to provide heat for the decomposition reaction in the reformer (4); and the heat distribution device (7) is also included, and the heat distribution device (7) is respectively connected to the burner The heat distribution device (7) is connected to the first heat exchanger (3) and the second heat exchanger (5) and is used to adjust the distribution of heat generated by the exhaust gas of the burner (2) between the first heat exchanger (3) and the second heat exchanger (5); the heat distribution device (7) comprises a fan (71) and a third heat exchanger (72); the third heat exchanger (72) is respectively connected to the fan (71), the burner (2), the first heat exchanger (3) and the second heat exchanger (5); when the fan 71 is not working, the heat of the third heat exchanger (72) is transferred to The first heat exchanger (3) is used to heat the hydrogen and air entering the first heat exchanger (3); when the fan (71) is turned on, the air enters the third heat exchanger (72) and flows in the direction of the second heat exchanger (5), and takes away part of the heat in the third heat exchanger (72) and transmits it to the second heat exchanger (5), and the remaining heat in the third heat exchanger (72) is transmitted to the first heat exchanger (3) to heat the hydrogen and air. A buffer tank (41) is provided between the reformer (4) and the first heat exchanger (3).

2. The fuel cell power generation system according to claim 1, characterized in that: It also includes a fuel tank (6) which is connected to the reformer (4) and the burner (2) respectively, and provides the reformer (4) with decomposition products and the burner (2) with combustion raw materials.

3. The fuel cell power generation system according to claim 2, characterized in that: The fuel tank (6) is connected to the burner (2) via a first electrically controlled valve (61), and the fuel tank (6) is connected to the reformer (4) via a second electrically controlled valve (62). Before the solid oxide fuel cell stack (1) starts working, the first electrically controlled valve (61) and the second electrically controlled valve (62) are both opened, and the fuel in the fuel tank (6) enters the burner (2) and the reformer (4) respectively; after the solid oxide fuel cell stack (1) starts working, the first electrically controlled valve (61) is closed, the second electrically controlled valve (62) is opened, and the fuel in the fuel tank (6) enters the reformer (4).

4. The fuel cell power generation system according to claim 2, characterized in that: A variable flow pump (63) and a pressure sensor (64) are provided at the outlet of the fuel tank (6).

5. The fuel cell power generation system according to claim 1, characterized in that: The fan (71) and the third heat exchanger (72) are connected via a check valve (73).

6. The fuel cell power generation system according to claim 1, characterized in that: The first heat exchanger (3) is selected from one of the following: a plate heat exchanger, a tube heat exchanger, and a floating head heat exchanger.

7. The fuel cell power generation system according to claim 1, characterized in that: The second heat exchanger (5) is a plate heat exchanger, and the medium in the second heat exchanger (5) is selected from one of oil, ethylene glycol, and a mixture of water and ethylene glycol.

8. The fuel cell power generation system according to claim 1, characterized in that: The third heat exchanger (72) is selected from one of the following: a plate heat exchanger, a tube heat exchanger, and a floating head heat exchanger.

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