Air-cooled methanol reforming fuel cell system

Abstract

The invention discloses an air cooling type methanol reforming fuel cell system which comprises a combustion chamber, a reforming chamber, a fuel cell, an integrated heat exchanger and an auxiliary component, and the auxiliary component comprises a gas mixing chamber; the combustion chamber is used for supplying heat to the reforming chamber and generating combustion tail gas, the combustion tail gas flows through the integrated heat exchanger, flows into the gas mixing chamber after heat exchange and is mixed with air to form a heat management medium, and the heat management medium flows into the heat management flow channel and is used for preheating or cooling a fuel cell; methanol reforming raw materials are subjected to heat exchange through the integrated heat exchanger and then flow into the reforming chamber to be subjected to methanol reforming reaction, and a first working medium is generated; a first working medium flows through the integrated heat exchanger from the outlet of the reforming chamber, and flows into the anode reaction runner after heat exchange; and a second working medium flows into the cathode reaction runner after being subjected to heat exchange through the integrated heat exchanger. Mixed gas of air in the external environment and tail gas generated by the combustion chamber in the system is adopted as a heat management medium, heat management components of the system are simplified, and the starting speed and the specific power of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to an air-cooled methanol reforming fuel cell system. Background Art

[0002] Fuel cells are considered to be a new type of energy conversion technology that can convert chemical energy stored in fuel into electrical energy and thermal energy through electrochemical reactions with high energy conversion efficiency. Methanol reforming fuel cells have broad application prospects due to their wide fuel sources, easy transportation and storage, and low operation and maintenance costs. Among them, high-temperature proton exchange membrane fuel cells (HT-PEMFCs) have attracted widespread attention due to their high CO tolerance and the ability to directly use hydrogen-rich gas after methanol reforming.

[0003] However, the operating temperature of HT-PEMFCs is usually high, which requires the battery system to have effective thermal management capabilities to maintain a stable operating state. In the prior art, due to the low ambient air temperature, in order to avoid excessive temperature differences causing battery temperature fluctuations, thermal oil is often used as a thermal management medium to achieve preheating of the battery and effectively transfer and control the internal heat of the battery. Thermal oil has good thermal and chemical stability and can work for a long time in a high temperature environment without decomposition.

[0004] Although thermal oil has certain advantages in thermal management, there are still some problems that need to be solved in the existing system design. First, in order to realize the circulation of thermal oil, the system needs to be equipped with additional components such as thermal oil pump, thermal oil tank and thermal oil radiator. The addition of these components increases the complexity and cost of the system and reduces the specific power of the system. Secondly, due to the large specific heat capacity of thermal oil, its heating rate is relatively slow, which limits the startup speed of the fuel cell system and affects the response performance of the system. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of low specific power and slow start-up speed of the current high-temperature methanol reforming fuel cell system.

[0006] In order to achieve the above object, the present invention provides an air-cooled methanol reforming fuel cell system, comprising a combustion chamber, a reforming chamber, a fuel cell, an integrated heat exchanger and auxiliary components, wherein:

[0007] The fuel cell comprises an anode reaction channel, a cathode reaction channel, and a thermal management channel; the working medium of the fuel cell comprises a first working fluid and a second working fluid;

[0008] The auxiliary component includes a gas mixing chamber;

[0009] The combustion chamber is used to generate combustion exhaust gas; the outlet of the combustion chamber is connected with the integrated heat exchanger, the gas mixing chamber, and the thermal management flow channel in sequence, the combustion exhaust gas flows from the outlet of the combustion chamber through the integrated heat exchanger, after heat exchange, flows into the gas mixing chamber to mix with the air introduced into the gas mixing chamber to form a thermal management medium, and flows into the thermal management flow channel to preheat or cool the fuel cell;

[0010] The inlet of the reforming chamber is connected to the integrated heat exchanger; the methanol reforming raw material flows into the reforming chamber after heat exchange through the integrated heat exchanger to undergo a methanol reforming reaction and generate the first working medium; the outlet of the reforming chamber is connected to the integrated heat exchanger and the anode reaction channel in sequence, and the first working medium flows from the outlet of the reforming chamber through the integrated heat exchanger, and after heat exchange, flows into the anode reaction channel to undergo an anode reaction;

[0011] The integrated heat exchanger is in communication with the cathode reaction channel, and the second working fluid flows into the cathode reaction channel to undergo cathode reaction after heat exchange through the integrated heat exchanger.

[0012] Furthermore, the fuel used to generate the combustion exhaust gas includes a first fuel and / or a second fuel, the first fuel is a methanol solution, and the second fuel is an anode exhaust gas discharged from the outlet of the anode reaction channel of the fuel cell; the oxidant used to generate the combustion exhaust gas is air.

[0013] Furthermore, the integrated heat exchanger includes a first working fluid layer, a second working fluid layer, a combustion tail gas layer, and a methanol reforming raw material layer;

[0014] The combustion tail gas layer is used to cool the combustion tail gas; the outlet of the combustion tail gas layer is connected to the inlet of the gas mixing chamber;

[0015] The methanol reforming raw material layer is used to gasify the methanol reforming raw material, and the outlet of the methanol reforming raw material layer is connected to the inlet of the reforming chamber;

[0016] The first working medium layer is used to cool the first working medium, and the outlet of the first working medium layer is connected to the inlet of the anode reaction channel;

[0017] The second working medium layer is used to preheat the second working medium, and the outlet of the second working medium layer is connected to the inlet of the cathode reaction channel.

[0018] Furthermore, the first working fluid is hydrogen-rich gas generated after a methanol reforming reaction occurs in the reforming chamber, and the second working fluid is air.

[0019] Furthermore, the auxiliary component also includes an air valve, which is connected to the gas mixing chamber and is used to introduce air into the gas mixing chamber. The flow rate of the air flowing into the gas mixing chamber is adjusted by adjusting the opening of the air valve.

[0020] Furthermore, the auxiliary component further includes a fan, which is communicated with an outlet of the thermal management channel and is used to discharge the thermal management medium.

[0021] Furthermore, the fan is a suction fan with an air flow hood.

[0022] Furthermore, the auxiliary component also includes a three-way valve, which includes an inlet valve, a first outlet valve, and a second outlet valve; the inlet valve is connected to the outlet of the combustion exhaust gas layer, and the first outlet valve is connected to the gas mixing chamber, so that the combustion exhaust gas flows into the gas mixing chamber; the second outlet valve is connected to the external environment; the flow rate of the combustion exhaust gas flowing into the gas mixing chamber is adjusted by adjusting the opening of the first outlet valve and the second outlet valve.

[0023] Further, during the startup phase of the fuel cell, the first outlet valve of the three-way valve is opened, and the second outlet valve is closed.

[0024] Furthermore, during the stable operation stage of the fuel cell, the flow rate of the combustion exhaust gas flowing into the gas mixing chamber is controlled by adjusting the openings of the first outlet valve and the second outlet valve of the three-way valve.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] (1) The present invention sets up a gas mixing chamber, and passes air and the combustion exhaust gas generated in the combustion chamber into the gas mixing chamber, and the two are mixed in the gas mixing chamber in appropriate amounts to form a mixed gas of appropriate temperature, thereby realizing that the mixed gas of air and the combustion exhaust gas generated in the combustion chamber is used as the thermal management medium of the fuel cell, replacing the traditional thermal oil. On the one hand, during the startup phase, there is no need to use thermal oil, which saves the step of preheating the thermal oil, and the reaction speed of the catalytic combustion reaction is faster, which significantly speeds up the preheating speed of the fuel cell and shortens the startup time of the entire system; on the other hand, the present invention does not need to set up a thermal oil pump, a thermal oil tank, a thermal oil radiator, etc., which can simplify the thermal management components of the system, reduce the system volume, and thus improve the specific power of the system.

[0027] (2) Furthermore, by adjusting the opening of the first outlet valve, the second outlet valve and the air valve connected to the gas mixing chamber in the three-way valve, the flow ratio of air to combustion exhaust gas in the thermal management medium can be adjusted, thereby achieving rapid adjustment of the temperature of the thermal management medium, alleviating the problems of large temperature difference between the thermal management medium and the fuel cell and poor temperature uniformity of the fuel cell caused by the low ambient temperature in traditional air-cooled high-temperature fuel cells, thereby improving the power generation performance and operational reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the air-cooled methanol reforming fuel cell system of the present invention.

[0029] Description of the accompanying drawings:

[0030] Combustion chamber 10, combustion chamber first inlet 11, combustion chamber second inlet 12, combustion chamber third inlet 13, combustion chamber outlet 14,

[0031] reforming chamber 20, reforming chamber inlet 21, reforming chamber outlet 22,

[0032] Integrated heat exchanger 30, first working medium layer 31, methanol reforming raw material layer 32, combustion tail gas layer 33, second working medium layer 34,

[0033] Fuel cell 40, anode inlet 41, anode outlet 42, cathode inlet 43, cathode outlet 44, thermal management inlet 45, thermal management outlet 46,

[0034] The first methanol pump 50,

[0035] The first fan 60,

[0036] Three-way valve 70, inlet valve 71, first outlet valve 72, second outlet valve 73,

[0037] The second methanol pump 80,

[0038] The second fan 90,

[0039] A gas mixing chamber 100, a first gas mixing chamber inlet 101, a second gas mixing chamber inlet 102,

[0040] Air valve 110,

[0041] Fan 120,

[0042] The flow route R1 of the heat management medium, the flow route R2 of the first working fluid, the flow route R3 of the methanol solution, and the flow route R4 of the second working fluid. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The “methanol reforming reaction” and “methanol steam reforming reaction” described herein are used interchangeably.

[0047] The "methanol reforming fuel cell" described herein is an energy conversion system that uses methanol water as fuel, converts it into hydrogen-rich gas through a reforming process inside the device, and then uses the hydrogen-rich gas obtained by the reforming to undergo an electrochemical reaction with oxygen in a high-temperature proton exchange membrane fuel cell to generate electrical energy. The reforming process includes: methanol vapor and water vapor undergo a reforming reaction at a high temperature (200°C to 300°C) to generate hydrogen-rich gas, and the hydrogen-rich gas includes hydrogen, carbon dioxide, a small amount of carbon monoxide, and unreacted methanol vapor and water vapor, wherein the molar fraction of the hydrogen is greater than or equal to 75%.

[0048] As described in the background technology, in the prior art, high-temperature proton exchange membrane fuel cells use thermal oil as a preheating system and a thermal management medium for system heat dissipation. On the one hand, the thermal oil has a slow heating rate, which reduces the startup speed of the system; on the other hand, controlling the circulation of the thermal oil in the system requires more and larger additional thermal management components, resulting in a lower system power density. The low power density of the system means that the system can provide limited energy output per unit weight or unit volume. This is a significant disadvantage for applications that require high power density, such as portable power supplies, drones, etc.

[0049] To solve the above problems, the present invention provides an air-cooled methanol reforming fuel cell system, which uses a mixture of air and combustion exhaust gas instead of heat transfer oil as the thermal management medium of the fuel cell, which can simplify the thermal management components of the system, reduce the system volume, and improve the system specific power. Moreover, since there is no need to preheat the heat transfer oil, the fuel cell preheating speed can be effectively accelerated and the system startup time can be shortened.

[0050] The present invention provides an air-cooled methanol reforming fuel cell system, wherein the working process of the air-cooled methanol reforming fuel cell system includes a startup phase and a stable operation phase. The present invention comprises a combustion chamber, wherein during the operation of the system, fuel and oxidant are introduced into the combustion chamber, a catalytic combustion reaction occurs, and a combustion exhaust gas is generated. The present invention sets up a gas mixing chamber, and uses a mixture of air and combustion exhaust gas as a heating medium or a cooling medium to control the heat balance of the fuel cell, so that it is maintained at the operating temperature of the fuel cell of 140°C to 220°C. During the startup phase, the fuel is a pumped methanol solution; during the stable operation phase, the fuel is the anode exhaust gas of the fuel cell. The present invention adjusts the flow ratio of the air and combustion exhaust gas so that the mixture of the air and combustion exhaust gas forms a thermal management medium of appropriate temperature, preheats the fuel cell or dissipates heat for the fuel cell.

[0051] Combine the following Figure 1 The present invention will be described in detail.

[0052] like Figure 1 As shown, an air-cooled methanol reforming fuel cell system provided by the present invention includes a fuel cell 40, a combustion chamber 10, a reforming chamber 20, an integrated heat exchanger 30 and auxiliary components.

[0053] The fuel cell 40 includes an anode reaction channel, a cathode reaction channel, and a thermal management channel. The anode reaction channel includes an anode inlet 41 and an anode outlet 42. The cathode reaction channel includes a cathode inlet 43 and a cathode outlet 44. The thermal management channel includes a thermal management inlet 45 and a thermal management outlet 46. The working medium of the fuel cell 40 includes a first working fluid and a second working fluid. In some embodiments, the first working fluid is a hydrogen-rich gas and the second working fluid is air. The first working fluid enters the fuel cell 40 from the anode inlet 41, and an anode reaction occurs: H2→2H + +2e - The unreacted first working medium forms anode tail gas and flows out from the anode outlet 42; the second working medium enters the fuel cell 40 from the cathode inlet 43, and a cathode reaction occurs: O2+4H + +4e - →2H2O, the unreacted second working fluid and the water generated by the reaction are discharged from the cathode outlet 44 to the external environment.

[0054] The combustion chamber 10 includes a first combustion chamber inlet 11, a second combustion chamber inlet 12, a third combustion chamber inlet 13, and a combustion chamber outlet 14. The combustion chamber 10 simultaneously introduces fuel and oxidant into the interior thereof through different inlets, and a catalytic combustion reaction occurs to generate combustion exhaust gas, which flows out from the combustion chamber outlet 14. In some embodiments, the fuel includes a first fuel and / or a second fuel, the first fuel is a methanol solution, the second fuel is the anode exhaust gas, and the oxidant is air.

[0055] The reforming chamber 20 includes a reforming chamber inlet 21 and a reforming chamber outlet 22. Methanol vapor and water vapor are introduced into the reforming chamber inlet 21 to cause a methanol-water vapor reforming reaction to generate the first working fluid, which flows out from the reforming chamber outlet 22.

[0056] The integrated heat exchanger 30 includes a first working medium (hydrogen-rich gas) layer 31, a methanol reforming raw material layer 32, a combustion tail gas layer 33, and a second working medium (air) layer 34. The first working medium layer 31, the methanol reforming raw material layer 32, the combustion tail gas layer 33, and the second working medium layer 34 are independent heat exchange units. In the integrated heat exchanger 30, four heat exchange units are integrated in a compact space, and heat exchange can be performed with each other through the heat transfer surface of the heat exchange unit. The integrated heat exchanger 30 of the present invention can simultaneously achieve through heat exchange: cooling the first working medium generated by the methanol steam reforming reaction, preheating the second working medium introduced from the external environment, cooling the combustion tail gas from the combustion chamber 10, and gasifying the pumped-in methanol solution as a reaction raw material for the methanol steam reforming reaction.

[0057] The auxiliary components include a first methanol pump 50, a second methanol pump 80, a first blower 60, a second blower 90, and a gas mixing chamber 100. The gas mixing chamber 100 includes a first gas mixing chamber inlet 101, a second gas mixing chamber inlet 102, and a gas mixing chamber outlet. The first gas mixing chamber inlet 101 allows the combustion exhaust gas to pass through, and the second gas mixing chamber inlet 102 allows the normal temperature air to pass through. The combustion exhaust gas and the normal temperature air are fully mixed in the gas mixing chamber 100 to form a thermal management medium of appropriate temperature, which flows out from the gas mixing chamber outlet.

[0058] The connection relationship between the combustion chamber 10, the reforming chamber 20, the fuel cell 40, the integrated heat exchanger 30 and various auxiliary components, as well as the flow directions of the thermal management medium, the methanol solution, the first working fluid and the second working fluid are described in detail below.

[0059] Figure 1 The R1 shown shows the flow path of the thermal management medium in the air-cooled methanol reforming fuel cell system. The first blower 60 is connected to the first inlet 11 of the combustion chamber for introducing air into the combustion chamber 10; the first methanol pump 50 is connected to the second inlet 12 of the combustion chamber for pumping methanol solution into the combustion chamber 10, and the methanol solution can participate in the catalytic combustion reaction as a fuel; the anode outlet 42 of the fuel cell 40 is connected to the third inlet 13 of the combustion chamber for introducing anode tail gas into the combustion chamber 10, and the anode tail gas mainly contains hydrogen, which can participate in the catalytic combustion reaction as another fuel. After the air as an oxidant and the methanol solution or anode tail gas as a fuel enter the combustion chamber 10, a catalytic combustion reaction of air and methanol solution or a catalytic combustion reaction of air and anode tail gas occurs in the combustion chamber 10, generating a combustion tail gas of 400°C to 600°C, and the combustion tail gas contains carbon dioxide and / or water vapor. The combustion chamber outlet 14 is connected to the inlet of the combustion tail gas layer 33 of the integrated heat exchanger 30. The combustion tail gas carries part of the reaction heat into the combustion tail gas layer 33 of the integrated heat exchanger 30 to perform heat exchange, and heats the integrated heat exchanger 30 to a temperature above the evaporation temperature of the methanol solution. The outlet of the combustion tail gas layer 33 is connected to the first inlet 101 of the gas mixing chamber. The combustion tail gas flows into the gas mixing chamber 100 from the outlet of the combustion tail gas layer 33, and mixes with the normal temperature air introduced into the second inlet 102 of the gas mixing chamber to form a heat management medium of appropriate temperature. The outlet of the gas mixing chamber is connected to the heat management inlet 45 of the fuel cell 40. The heat management medium flows into the heat management inlet 45 from the outlet of the gas mixing chamber to heat or cool the fuel cell 40, and is finally discharged to the external environment from the heat management outlet 46.

[0060] In order to quickly and accurately adjust the temperature of the thermal management medium, the flow rate of the normal temperature air flowing into the gas mixing chamber 100 can be adjusted to adjust the flow rate ratio of the combustion exhaust gas and the air, thereby adjusting the temperature of the thermal management medium. In some embodiments, the auxiliary component further includes an air valve 110. The inlet of the air valve 110 is connected to the external environment, and the outlet of the air valve 110 is connected to the second inlet 102 of the gas mixing chamber, which is used to pass normal temperature air into the second inlet 102 of the gas mixing chamber. The opening of the air valve 110 is adjustable. By adjusting the opening of the air valve 110, the air flow rate flowing into the gas mixing chamber 100 is adjusted to adjust the flow rate ratio of the combustion exhaust gas and the air. The normal temperature air can absorb the heat of the high temperature combustion exhaust gas in the gas mixing chamber 100, so that the temperature of the thermal management medium formed by the mixture can adapt to the requirements of the startup stage and the stable operation stage of the combustion battery 40, and heat or cool the fuel cell 40.

[0061] In order to further quickly and accurately adjust the temperature of the thermal management medium, the flow rate of the combustion exhaust gas flowing into the gas mixing chamber 100 can be adjusted to adjust the flow rate ratio of the combustion exhaust gas and the air, thereby adjusting the temperature of the thermal management medium. In some embodiments, the auxiliary component also includes a three-way valve 70. The three-way valve 70 includes an inlet valve 71, a first outlet valve 72, and a second outlet valve 73. The inlet valve 71 is connected to the outlet of the combustion exhaust gas layer 33 of the integrated heat exchanger 30, and the first outlet valve 72 is connected to the first inlet 101 of the gas mixing chamber, so that the combustion exhaust gas flows into the gas mixing chamber 100; the second outlet valve 73 is connected to the external environment. When the second outlet valve 73 is opened, part of the combustion exhaust gas can carry part of the heat and flow out to the external environment through the second outlet valve 73. By adjusting the opening of the first outlet valve 72, the flow rate of the combustion exhaust gas flowing into the gas mixing chamber 100 can be adjusted; by adjusting the opening of the second outlet valve 73, the flow rate of the combustion exhaust gas flowing out to the external environment can be adjusted, thereby adjusting the flow rate of the combustion exhaust gas flowing into the gas mixing chamber 100, and further adjusting the flow rate ratio of the combustion exhaust gas and air in the gas mixing chamber 100, so that the temperature of the mixed thermal management medium can adapt to the requirements of the startup stage and the stable operation stage of the combustion cell 40, and heat or cool the fuel cell 40. As an example, in the startup stage of the fuel cell 40, the first outlet valve 72 is fully opened, the air valve 110 is opened, and the second outlet valve 73 is closed, so that the combustion exhaust gas and the air are respectively passed into the gas mixing chamber 100 through the first outlet valve 72 and the air valve 110, and the opening of the air valve 110 is adjusted, and the flow ratio of the air and the combustion exhaust gas is adjusted, so that the air and the combustion exhaust gas are mixed in the gas mixing chamber 100 to form a heating medium of 140°C to 220°C to preheat the fuel cell 40; in the stable operation stage of the fuel cell 40, the first outlet valve 72, the second outlet valve 73, and the air valve 110 are opened, and the opening of the first outlet valve 72, the second outlet valve 73, and the air valve 110 are adjusted, so that the air and the combustion exhaust gas are mixed in the gas mixing chamber 100 to form a cooling medium of 70°C to 90°C to dissipate heat for the fuel cell 40.

[0062] In order to achieve uniformity of the flow rate of the thermal management medium in the fuel cell 40, in some embodiments, the auxiliary component further includes a fan 120, and the fan 120 is preferably a suction fan with an airflow cover structure. The thermal management outlet 46 of the fuel cell 40 is connected to the fan 120, and the fan 120 is connected to the external environment to drive the flow of the thermal management medium in the fuel cell 40. The airflow cover structure can evenly distribute the airflow sucked by the fan 120, reduce the airflow dead angle inside the fuel cell 40, and help achieve uniformity of the flow rate of the thermal management medium in the fuel cell 40.

[0063] Figure 1 R2 shown shows the flow path of the first working medium, and R3 shows the flow path of the methanol solution. The second methanol pump 80 is connected to the inlet of the methanol reforming raw material layer 32 of the integrated heat exchanger 30, and is used to pump the methanol solution into the methanol reforming raw material layer 32. Since the combustion tail gas layer 33 has heated the integrated heat exchanger 30 to above the evaporation temperature of the methanol solution, the methanol solution can be gasified in the methanol reforming raw material layer 32 to form methanol vapor and water vapor. The outlet of the methanol reforming raw material layer 32 is connected to the reforming chamber inlet 21, and the methanol vapor and water vapor enter the reforming chamber 20 through the outlet of the methanol reforming raw material layer 32 and the reforming chamber inlet 21 in turn, and a methanol water vapor reforming reaction occurs at 200°C to 300°C to generate a first working medium (hydrogen-rich gas), and the first working medium is mainly hydrogen. The reforming chamber outlet 22 is connected to the inlet of the first working medium layer 31 of the integrated heat exchanger 30. The first working medium enters the first working medium layer 31 through the reforming chamber outlet 22 and the inlet of the first working medium layer 31 in sequence. The first working medium layer 31 is used to cool the first working medium at 200°C to 300°C to the operating temperature of 140°C to 220°C of the fuel cell 40. The outlet of the first working medium layer 31 is connected to the anode inlet 41 of the fuel cell 40. The first working medium enters the anode reaction channel through the outlet of the first working medium layer 31 and the anode inlet 41 of the fuel cell 40 in sequence, and an anode reaction occurs in the fuel cell 40. The unreacted first working medium forms the anode tail gas, which flows into the third inlet 13 of the combustion chamber from the anode outlet 42 as the second fuel.

[0064] In the above process, the temperature in the reforming chamber 20 is 200°C to 300°C, and this temperature range is achieved by heat exchange with the combustion chamber 10. Preferably, the combustion chamber 10 and the reforming chamber 20 are arranged closely together, and heat exchange can occur between the two. Part of the reaction heat generated by the catalytic combustion reaction in the combustion chamber 10 will be partially transferred to the reforming chamber 20, so as to preheat the temperature of the reforming chamber 20 to the temperature range of 200°C to 300°C for the methanol steam reforming reaction.

[0065] Figure 1 R4 shows the flow route of the second working fluid. The second fan 90 is connected to the inlet of the second working fluid layer 34 of the integrated heat exchanger 30, and is used to introduce the second working fluid (air) into the second working fluid layer 34. Since the combustion exhaust gas layer 33 has preheated the integrated heat exchanger 30, the second working fluid can be heated to above 100°C in the second working fluid layer 34. The outlet of the second working fluid layer 34 is connected to the cathode inlet 43 of the fuel cell 40, and the second working fluid enters the cathode reaction channel through the outlet of the second working fluid layer 34 and the cathode inlet 43 of the fuel cell 40 in turn, and a cathode reaction occurs in the fuel cell 40. The cathode outlet 44 of the fuel cell 40 is connected to the external environment, and the unreacted second working fluid and the water generated by the reaction are discharged from the cathode outlet 44 to the external environment.

[0066] The working process of the air-cooled methanol reforming fuel cell system of the present invention includes a startup phase and an operation phase, and its working principle is as follows:

[0067] During the startup phase, the methanol solution from the first methanol pump 50 is used as the fuel of the combustion chamber 10. The valve (i.e., the first outlet valve 72) of the three-way valve 70 connected to the first inlet 101 of the gas mixing chamber is fully opened, the valve connected to the external environment is closed (i.e., the second outlet valve 73), and the air valve 110 connected to the second inlet 102 of the gas mixing chamber is opened. The first methanol pump 50 and the first fan 60 respectively transport the methanol solution and air to the combustion chamber 10 for catalytic combustion reaction, and the generated reaction heat maintains the temperature of the combustion chamber 10 at 400°C to 600°C. The temperature of the combustion chamber 10 can be adjusted by the first fan 60, and the temperature can be lowered or raised by increasing or decreasing the exhaust frequency. Part of the heat released by the catalytic combustion reaction in the combustion chamber 10 is transferred to the reforming chamber 20, which is preheated to the temperature range of 200°C to 300°C for the methanol steam reforming reaction. The other part of the heat is taken away by the combustion exhaust gas and flows through the combustion exhaust gas layer 33 of the integrated heat exchanger 30, and the integrated heat exchanger 30 is preheated to above the evaporation temperature of the methanol solution. The combustion exhaust gas flowing through the integrated heat exchanger 30 enters the gas mixing chamber 100 after passing through the three-way valve 70. By adjusting the opening of the air valve 110, the combustion exhaust gas and air are mixed in the gas mixing chamber 100 to form a heating medium of 140°C to 220°C. The heating medium then enters the thermal management inlet 45 of the fuel cell 40, and the fuel cell 40 is preheated to the operating temperature of 140°C to 220°C. When the reforming chamber 20, the integrated heat exchanger 30 and the fuel cell 40 all reach the target temperature, the preheating is completed, and the air-cooled methanol reforming fuel cell system is in operation.

[0068] In the stable operation stage, the anode tail gas from the fuel cell 40 is used as the fuel of the combustion chamber. The first outlet valve 72, the second outlet valve 73, and the air valve 110 are all opened, and the first methanol pump 50 is closed. The second methanol pump 80 delivers methanol solution to the integrated heat exchanger 30. The methanol solution enters the reforming chamber 20 after being gasified in the methanol reforming raw material layer 32 to undergo a methanol steam reforming reaction. The hydrogen-rich gas (200°C to 300°C) generated by the reaction enters the first working medium layer 31 of the integrated heat exchanger 30, and enters the anode inlet 41 of the fuel cell 40 after the first working medium layer 31 is cooled to the operating temperature of the fuel cell 40 (140°C to 220°C). At the same time, the second fan 90 delivers air to the integrated heat exchanger 30, and enters the cathode inlet 43 of the fuel cell 40 after being preheated to above 100°C in the second working medium layer 34. The anode exhaust gas at the anode outlet 42 of the fuel cell 40 enters the combustion chamber 10 to replace the methanol solution delivered by the first methanol pump 50 in the startup phase for catalytic combustion reaction. Part of the heat released is transferred to the reforming chamber 20 for methanol steam reforming reaction, and the other part of the heat is taken away by the combustion exhaust gas, flows through the combustion exhaust gas layer 33 of the integrated heat exchanger 30 and enters the three-way valve 70. A part of the combustion exhaust gas flows out from the first outlet valve 72 of the three-way valve 70 and enters the gas mixing chamber 100. By adjusting the opening of the first outlet valve 72, the second outlet valve 73 and the air valve 110, the mixing ratio of air and combustion exhaust gas is adjusted, so that the combustion exhaust gas and air are mixed in the gas mixing chamber 100 to form a cooling medium with a temperature of 70°C to 90°C. The cooling medium then enters the thermal management inlet 45 of the fuel cell 40, and the reaction heat of the fuel cell 40 is discharged through the thermal management outlet 46 of the fuel cell 40 and the fan 120 in turn.

[0069] Example

[0070] The system startup phase is a transient process. As the startup process progresses, the heat transfer changes in real time. Therefore, this embodiment only describes the specific operating parameters of the stable operation phase.

[0071] When the system is in the stable operation stage, the first methanol pump 50 is turned off, and the second methanol pump 80 delivers a 25°C methanol solution (the molar ratio of methanol to water is 4:6) to the integrated heat exchanger 30, with a liquid inlet rate of 3.4 kg / h. After absorbing 1.98 kW of heat in the integrated heat exchanger 30, the mixed gas of methanol vapor and water vapor is heated to 180°C and enters the reforming chamber 20.

[0072] A methanol steam reforming reaction occurs in the reforming chamber 20, with a conversion rate of 95%, a reaction temperature of 250°C, an endothermic reaction of 1.06kW, and an outlet of 250°C first working fluid (hydrogen-rich gas), wherein the molar fraction of CO is 1%, and the mass flow rate of hydrogen is 0.3kg / h. The hydrogen-rich gas enters the integrated heat exchanger 30, releases 0.17kW of heat, and cools down to 180°C, and enters the anode inlet 41 of the fuel cell 40, and the stoichiometric ratio of the hydrogen-rich gas is 1.5.

[0073] The second fan 90 delivers air at 25°C to the integrated heat exchanger 30 with an intake volume of 15.5kg / h. After absorbing 0.25kW of heat in the integrated heat exchanger 30, the air is heated to 100°C and enters the cathode inlet 43 of the fuel cell 40. The second working fluid (air) metering ratio is 2.

[0074] According to the test and calculation, the power generation efficiency of the fuel cell 40 is 50%. The mass flow rate of hydrogen in the anode tail gas after power generation is 0.1kg / h, and the temperature is 160°C, and it enters the combustion chamber 10 for catalytic combustion. 1.06kW of the combustion heat is transferred to the reforming chamber 20, so that the reforming chamber 20 is maintained at 250°C, and the remaining heat is taken away by the combustion tail gas. The mass flow rate of the combustion tail gas is 28.5kg / h and the temperature is 450°C. The combustion tail gas releases 2.06kW of heat in the integrated heat exchanger 30, which is used to gasify the methanol solution and preheat the second working medium (air). The outlet temperature of the combustion tail gas layer 33 of the integrated heat exchanger 30 is 217°C.

[0075] The first outlet valve 72 of the three-way valve 70 is fully opened, and the second outlet valve 73 is closed. The temperature of the combustion exhaust layer 33 outlet of the integrated heat exchanger 30 is 217°C, and the combustion exhaust gas with a mass flow rate of 28.5kg / h all enters the gas mixing chamber 100, and is mixed with air with a temperature of 25°C and a mass flow rate of 110.0kg / h to form a cooling medium of 75°C, which enters the thermal management inlet 45 of the fuel cell 40. After absorbing the reaction heat generated by the fuel cell 40, the temperature of the thermal management outlet is 160°C, which is discharged to the surrounding environment through the fan 120.

[0076] In summary, the present invention uses a mixture of air and combustion exhaust gas as the thermal management medium of the fuel cell, replacing the traditional heat transfer oil, thereby achieving rapid preheating and system simplification. In the startup phase, the catalytic combustion reaction in the combustion chamber produces high-temperature combustion exhaust gas, which is mixed with air through an integrated heat exchanger and a three-way valve to form a heating medium, eliminating the process of heating the thermal oil, speeding up the preheating speed of the fuel cell and shortening the startup time. During stable operation, the anode exhaust gas is used as the combustion chamber fuel, reducing emissions and improving energy efficiency. In the integrated heat exchanger preheated by the combustion exhaust gas, the temperature regulation of the working fluid and the gasification of the methanol solution are achieved through heat exchange, maintaining the efficient operation of the fuel cell. By adjusting the three-way valve and the air valve, the temperature of the thermal management medium can be quickly adjusted, and the temperature difference between the thermal management medium and the fuel cell can be reduced, so as to better control the temperature inside the fuel cell, maintain a uniform temperature, and thus improve the power generation performance and reliability of the system.

[0077] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. An air-cooled methanol reforming fuel cell system, characterized in that: It includes a combustion chamber, a reforming chamber, a fuel cell, an integrated heat exchanger and auxiliary components, wherein: The fuel cell comprises an anode reaction channel, a cathode reaction channel, and a thermal management channel; the working medium of the fuel cell comprises a first working fluid and a second working fluid; The auxiliary component includes a gas mixing chamber; The combustion chamber is used to generate combustion exhaust gas; the outlet of the combustion chamber is connected with the integrated heat exchanger, the gas mixing chamber, and the thermal management flow channel in sequence, the combustion exhaust gas flows from the outlet of the combustion chamber through the integrated heat exchanger, after heat exchange, flows into the gas mixing chamber to mix with the air introduced into the gas mixing chamber to form a thermal management medium, and flows into the thermal management flow channel to preheat or cool the fuel cell; The inlet of the reforming chamber is connected to the integrated heat exchanger; the methanol reforming raw material flows into the reforming chamber after heat exchange through the integrated heat exchanger to undergo a methanol reforming reaction and generate the first working medium; the outlet of the reforming chamber is connected to the integrated heat exchanger and the anode reaction channel in sequence, and the first working medium flows from the outlet of the reforming chamber through the integrated heat exchanger, and after heat exchange, flows into the anode reaction channel to undergo an anode reaction; The integrated heat exchanger is in communication with the cathode reaction channel, and the second working fluid flows into the cathode reaction channel to undergo cathode reaction after heat exchange through the integrated heat exchanger.

2. The air-cooled methanol reforming fuel cell system according to claim 1, characterized in that: The fuel used to generate the combustion exhaust gas includes a first fuel and / or a second fuel, the first fuel is a methanol solution, and the second fuel is the anode exhaust gas discharged from the outlet of the anode reaction channel of the fuel cell; the oxidant used to generate the combustion exhaust gas is air.

3. The air-cooled methanol reforming fuel cell system according to claim 1, characterized in that: The integrated heat exchanger comprises a first working medium layer, a second working medium layer, a combustion tail gas layer, and a methanol reforming raw material layer; The combustion tail gas layer is used to cool the combustion tail gas; the outlet of the combustion tail gas layer is connected to the inlet of the gas mixing chamber; The methanol reforming raw material layer is used to gasify the methanol reforming raw material, and the outlet of the methanol reforming raw material layer is connected to the inlet of the reforming chamber; The first working medium layer is used to cool the first working medium, and the outlet of the first working medium layer is connected to the inlet of the anode reaction channel; The second working medium layer is used to preheat the second working medium, and the outlet of the second working medium layer is connected to the inlet of the cathode reaction channel.

4. The air-cooled methanol reforming fuel cell system according to claim 1, characterized in that: The first working fluid is hydrogen-rich gas generated by a methanol reforming reaction in the reforming chamber, and the second working fluid is air.

5. The air-cooled methanol reforming fuel cell system according to claim 1, characterized in that: The auxiliary component also includes an air valve, which is communicated with the gas mixing chamber and is used to introduce air into the gas mixing chamber. The flow rate of the air flowing into the gas mixing chamber is adjusted by adjusting the opening of the air valve.

6. The air-cooled methanol reforming fuel cell system according to claim 1, characterized in that: The auxiliary component further includes a fan, which is communicated with an outlet of the thermal management channel and is used to discharge the thermal management medium.

7. The air-cooled methanol reforming fuel cell system according to claim 6, characterized in that: The fan is a suction fan with an air flow cover.

8. The air-cooled methanol reforming fuel cell system according to claim 3, characterized in that: The auxiliary component also includes a three-way valve, which includes an inlet valve, a first outlet valve, and a second outlet valve; the inlet valve is connected to the outlet of the combustion exhaust gas layer, and the first outlet valve is connected to the gas mixing chamber, so that the combustion exhaust gas flows into the gas mixing chamber; the second outlet valve is connected to the external environment; the flow rate of the combustion exhaust gas flowing into the gas mixing chamber is adjusted by adjusting the opening of the first outlet valve and the second outlet valve.

9. The air-cooled methanol reforming fuel cell system according to claim 8, characterized in that: During the startup phase of the fuel cell, the first outlet valve of the three-way valve is opened, and the second outlet valve is closed.

10. The air-cooled methanol reforming fuel cell system according to claim 8, characterized in that: In the stable operation stage of the fuel cell, the flow rate of the combustion exhaust gas flowing into the gas mixing chamber is controlled by adjusting the openings of the first outlet valve and the second outlet valve of the three-way valve.

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