Fuel cell fuel circulation device and fuel cell

Abstract

The utility model discloses a fuel cell fuel circulating device and a fuel cell, and belongs to the technical field of fuel cells. According to the fuel circulation device of the fuel cell and the fuel cell, the anode tail gas of the first-stage electric pile is divided into two parts, one part is directly sent back to the anode inlet of the first-stage electric pile through the second anode circulation pipeline to be recycled, and the other part is dewatered through the condenser and the first water-gas separator to be recycled. The anode tail gas is introduced into the first-stage electric pile through a first anode circulating pipeline and then is introduced into the second-stage electric pile through a first anode circulating pipeline for recycling, or the anode tail gas of the first-stage electric pile is dewatered through a condenser and a first water-gas separator, and then the dewatered anode tail gas of the first-stage electric pile is divided into two parts; wherein one part is introduced into the anode inlet of the first-stage electric pile through the second anode circulating pipeline for recycling, and the other part is introduced into the second-stage electric pile through the first anode circulating pipeline for recycling, so that the fuel utilization rate and the voltage efficiency of the second-stage electric pile are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cells, in particular to a fuel cell fuel circulation device and a fuel cell. Background Art

[0002] In the prior art, a two-stage fuel cell includes a primary stack and a secondary stack connected in series, wherein air flows through the primary stack and the secondary stack in sequence through an air pipeline, and fuel flows through the primary stack and the secondary stack in sequence through a fuel pipeline. In the two-stage fuel cell, the fuel content in the fuel mixed gas flowing through the secondary stack is low, resulting in a low voltage efficiency of the secondary stack; the fuel circulation volume is large, resulting in a large power consumption. Moreover, the fuel utilization rate is low and the power generation efficiency is low. Utility Model Content

[0003] The utility model aims to provide a fuel cell fuel circulation device and a fuel cell, which improves the fuel utilization rate and the fuel concentration entering the secondary stack, thereby facilitating the improvement of the voltage efficiency of the secondary stack.

[0004] In order to achieve the above objectives, the following technical solutions are provided:

[0005] In one aspect, a fuel cell fuel circulation device is provided, wherein the fuel cell comprises a primary stack and a secondary stack; the fuel cell fuel circulation device comprises:

[0006] A condenser, wherein the inlet of the condenser is used to be connected to the anode outlet of the primary stack;

[0007] a first water-gas separator, wherein an inlet of the first water-gas separator is connected to an outlet of the condenser;

[0008] A first anode circulation pipeline, one end of which is connected to the gas outlet of the first water-gas separator, and the other end of which is used to be connected to the anode inlet of the secondary fuel cell stack;

[0009] A second anode circulation pipeline, one end of which is connected to the gas outlet of the first water-gas separator or used to be connected to the anode outlet of the first-stage fuel cell stack, and the other end is used to be connected to the anode inlet of the first-stage fuel cell stack.

[0010] As an optional scheme for the fuel cell fuel circulation device, when one end of the second anode circulation pipeline is connected to the outlet of the first water-gas separator, a hydrogen separator is provided between the outlet of the first water-gas separator and the second anode circulation pipeline and the first anode circulation pipeline, and the hydrogen separator includes a separation inlet, a hydrogen outlet for outputting hydrogen, and a gas outlet for outputting other gases except hydrogen, the separation inlet is connected to the outlet of the first water-gas separator, the hydrogen outlet is connected to the second anode circulation pipeline, and the gas outlet is connected to the first anode circulation pipeline.

[0011] As an optional solution of the fuel cell fuel circulation device, the first anode circulation pipeline is provided with a circulation preheater.

[0012] As an optional solution for the fuel cell fuel circulation device, the circulation preheater includes a circulation heat exchanger, and the gas in the first anode circulation pipeline and the anode tail gas of the first-level fuel cell stack can exchange heat through the circulation heat exchanger.

[0013] As an optional scheme of the fuel cell fuel circulation device, the fuel cell fuel circulation device also includes a water supply pipeline, through which the liquid water separated by the first water-gas separator can enter the first anode circulation pipeline, and the circulation preheater can convert the liquid water entering the first anode circulation pipeline into water vapor.

[0014] As an optional solution of the fuel cell fuel circulation device, the fuel cell fuel circulation device also includes a burner, which can burn the anode exhaust gas of the secondary stack, and / or the cathode exhaust gas of the secondary stack, and / or the cathode exhaust gas of the primary stack.

[0015] As an optional solution of the fuel cell fuel circulation device, the fuel cell fuel circulation device also includes a second water-gas separator, the inlet of the second water-gas separator is used to be connected to the anode outlet of the secondary fuel cell stack, and the outlet of the second water-gas separator is connected to the burner.

[0016] As an optional solution of the fuel cell fuel circulation device, the fuel cell fuel circulation device further includes a carbon dioxide collector, and the carbon dioxide collector is arranged between the gas outlet of the second water-gas separator and the burner.

[0017] As an optional solution of the fuel cell fuel circulation device, the fuel cell fuel circulation device further includes a cathode heat exchanger, which can heat the cathode gas introduced into the primary stack through a cathode preheating medium, wherein the cathode preheating medium includes the tail gas of the burner, the cathode tail gas of the primary stack, or the cathode tail gas of the secondary stack;

[0018] The fuel cell fuel circulation device also includes an anode heat exchanger, which can heat the anode gas introduced into the primary stack through an anode preheating medium. The anode preheating medium includes the exhaust gas of the burner, the preheated cathode gas, the cathode exhaust gas of the primary stack, or the cathode exhaust gas of the secondary stack.

[0019] As an optional solution of the fuel cell fuel circulation device, the fuel cell fuel circulation device further includes a first cathode circulation pipeline, one end of which is connected to the cathode outlet of the first-stage fuel cell stack, and the other end is connected to the cathode inlet of the second-stage fuel cell stack;

[0020] The fuel cell fuel circulation device further comprises a second cathode circulation pipeline, one end of which is connected to the cathode outlet of the primary stack, and the other end of which is connected to the cathode inlet of the primary stack;

[0021] The fuel cell fuel circulation device also includes a third cathode circulation pipeline, one end of which is connected to the cathode outlet of the secondary fuel cell stack, and the other end of which is connected to the cathode inlet of the primary fuel cell stack.

[0022] On the other hand, a fuel cell is provided, comprising a primary stack, a secondary stack and a fuel cell fuel circulation device as described in any one of the above items, wherein the inlet of the condenser is connected to the anode outlet of the primary stack, one end of the first anode circulation pipeline is connected to the gas outlet of the first water vapor separator, and the other end is connected to the anode inlet of the secondary stack, one end of the second anode circulation pipeline is connected to the gas outlet of the first water vapor separator or to the anode outlet of the primary stack, and the other end is connected to the anode inlet of the primary stack.

[0023] Compared with the prior art, the utility model has the following beneficial effects:

[0024] The fuel cell fuel circulation device and fuel cell of the utility model divide the anode tail gas of the primary stack into two parts, one part of which is directly sent back to the anode inlet of the primary stack through the second anode circulation pipeline for recycling, and the other part is dehydrated through the condenser and the first water-gas separator, and then passed into the secondary stack through the first anode circulation pipeline for reuse; or the anode tail gas of the primary stack is first dehydrated through the condenser and the first water-gas separator, and then the anode tail gas of the primary stack after dehydration is divided into two parts, one part of which is passed into the anode inlet of the primary stack through the second anode circulation pipeline for recycling, and the other part is passed into the secondary stack through the first anode circulation pipeline for reuse, which improves the fuel utilization rate on the one hand, and improves the fuel concentration entering the secondary stack on the other hand, which is beneficial to improving the voltage efficiency of the secondary stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a first fuel cell in Embodiment 1 of the present utility model;

[0026] Figure 2 This is a schematic diagram of the structure of the second fuel cell in the first embodiment of the utility model;

[0027] Figure 3 This is a schematic diagram of the structure of the third fuel cell in the first embodiment of the utility model;

[0028] Figure 4 This is a schematic structural diagram of a fourth fuel cell in Embodiment 1 of the present utility model;

[0029] Figure 5 This is a schematic structural diagram of the fifth fuel cell in the first embodiment of the utility model;

[0030] Figure 6 This is a schematic diagram of the structure of the first fuel cell in the second embodiment of the utility model;

[0031] Figure 7 This is a schematic diagram of the structure of the second fuel cell in the second embodiment of the utility model;

[0032] Figure 8 This is a schematic diagram of the structure of the third fuel cell in the second embodiment of the present utility model;

[0033] Fig. 9 This is a schematic diagram of the structure of the fourth fuel cell in the second embodiment of the present utility model.

[0034] Reference numerals:

[0035] 1. Primary stack; 2. Secondary stack;

[0036] 31. Condenser; 32. First water-gas separator; 33. First anode circulation pipeline; 331. Circulating heat exchanger; 3311. Circulating high-temperature flow channel; 3312. Circulating low-temperature flow channel; 34. Second anode circulation pipeline; 341. Fuel circulation pump; 351. Reformer; 352. Fuel pipeline; 353. Water vapor pipeline; 361. Hydrogen separator; 362. Three-way valve; 37. Water supply pipeline; 371. Water pump; 38. Burner; 391. Second water-gas separator; 392. Carbon dioxide collector;

[0037] 3101, first cathode gas supply pipeline; 3102, first cathode circulation pipeline; 3103, cathode exhaust pipeline; 3104, second cathode circulation pipeline; 3105, third cathode circulation pipeline; 3106, second cathode gas supply pipeline. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. 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.

[0040] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0041] In the description of the present utility model, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply 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 a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0042] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set" and "connection" 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 or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0044] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0045] Embodiment 1

[0046] like Figure 1-5 As shown, this embodiment provides a fuel cell fuel circulation device and a fuel cell, wherein the fuel cell comprises a primary stack 1, a secondary stack 2 and a fuel cell fuel circulation device. In this embodiment, the anode gas of the fuel cell is methane, in other words, the fuel cell uses methane as fuel; the cathode gas is air.

[0047] The fuel cell fuel circulation device includes a condenser 31, a first water-gas separator 32, a first anode circulation pipeline 33 and a second anode circulation pipeline 34. The inlet of the condenser 31 is connected to the anode outlet of the first-stage fuel cell stack 1; the inlet of the first water-gas separator 32 is connected to the outlet of the condenser 31, and the gas outlet of the first water-gas separator 32 is connected to the first anode circulation pipeline 33 and the second anode circulation pipeline 34 respectively, the other end of the first anode circulation pipeline 33 is connected to the anode inlet of the second-stage fuel cell stack 2, and the other end of the second anode circulation pipeline 34 is connected to the anode inlet of the first-stage fuel cell stack 1.

[0048] The fuel circulation device of this embodiment first removes water from the anode exhaust gas of the first-stage fuel cell stack 1 through a condenser 31 and a first water-gas separator 32, and then divides the anode exhaust gas of the first-stage fuel cell stack 1 after dehydration into two parts, one part of which is passed into the anode inlet of the first-stage fuel cell stack 1 through a second anode circulation pipeline 34 for recycling, thereby improving the fuel utilization rate of the input fuel cell system under the premise that the fuel utilization rate of the fuel cell stack remains unchanged; the other part is passed into the second-stage fuel cell stack 2 through the first anode circulation pipeline 33 for reuse, that is, the anode sides of the two-stage fuel cell stacks are connected in series, and by removing water from the anode exhaust gas of the first-stage fuel cell stack 1, the fuel concentration entering the second-stage fuel cell stack 2 is increased, which is beneficial to improving the voltage efficiency of the second-stage fuel cell stack 2.

[0049] In this embodiment, the fuel cell fuel circulation device also includes a reformer 351, which is arranged at the anode inlet of the first-stage fuel stack 1, so that the fuel (methane) and water vapor are reformed through the reformer 351 and then introduced into the anode inlet of the first-stage fuel stack 1.

[0050] Furthermore, the fuel cell fuel circulation device also includes a fuel pipeline 352 and a water vapor pipeline 353. The fuel pipeline 352, the water vapor pipeline 353 and the other end of the second anode circulation pipeline 34 are all connected to the inlet of the reformer 351, so that the fuel, water vapor and the anode exhaust gas of the first-stage stack 1 after dehydration are reformed through the reformer 351 and then supplied to the first-stage stack 1.

[0051] It should be noted that the anode tail gas of the first-stage stack 1 after water removal is sent back to the first-stage stack 1 for recycling. Since the anode tail gas itself contains oxygen, if the oxygen-carbon ratio entering the reformer 351 is to be controlled unchanged, the supply of water vapor can be reduced.

[0052] Optionally, the second anode circulation pipeline 34 is provided with a fuel circulation pump 341, and fuel circulation is promoted by the fuel circulation pump 341. Of course, an ejector can also be used instead of the fuel circulation pump 341 to promote fuel circulation.

[0053] It is understandable that the greater the amount of circulating fuel, the greater the power consumption required. In this embodiment, the anode exhaust gas of the first-level fuel cell stack 1 is dehydrated and then sent back to the first-level fuel cell stack 1 for recycling. The concentrations of fuels such as hydrogen, carbon monoxide, and methane are improved. On the premise of circulating the same amount of fuel, the circulating amount can be reduced, thereby reducing the circulating fuel flow rate and the power consumption of the fuel cell fuel circulation device (such as the fuel circulation pump 341).

[0054] Furthermore, after the anode tail gas of the first-stage fuel cell stack 1 is dehydrated, the oxygen content is reduced, and even at a higher circulation rate, the oxygen-carbon ratio entering the first-stage fuel cell stack 1 can be maintained at a low level.

[0055] In this embodiment, Figure 1As shown, the fuel cell fuel circulation device also includes a hydrogen separator 361, which is arranged between the outlet of the first water-gas separator 32 and the second anode circulation pipeline 34 and the first anode circulation pipeline 33. The hydrogen separator 361 includes a separation inlet, a hydrogen outlet for outputting hydrogen, and a gas outlet for outputting other gases except hydrogen. The separation inlet is connected to the outlet of the first water-gas separator 32; the hydrogen outlet is connected to the second anode circulation pipeline 34; and the gas outlet is connected to the first anode circulation pipeline 33.

[0056] After the anode tail gas of the first-stage fuel cell stack 1 is dehydrated, the concentration of fuels such as hydrogen, carbon monoxide, and methane can be effectively increased, which is more conducive to the hydrogen separator 361 to separate pure hydrogen.

[0057] The anode tail gas of the first-level fuel cell stack 1 after dehydration is separated into pure hydrogen through the hydrogen separator 361, and the separated pure hydrogen is then returned to the anode inlet of the first-level fuel cell stack 1 through the second anode circulation pipeline 34 for recycling, and other gases except hydrogen, such as carbon monoxide, methane, etc., enter the anode inlet of the second-level fuel cell stack 2 through the first anode circulation pipeline 33 for secondary reaction, which not only improves the fuel utilization rate of the first-level fuel cell stack 1 and the overall fuel utilization rate of the fuel cell system, but also does not affect the water-carbon ratio of the first-level fuel cell stack 1.

[0058] In other embodiments, Figure 2 As shown, the hydrogen separator 361 may not be provided, and the anode tail gas of the first-stage fuel cell stack 1 after dehydration may be diverted by a three-way valve 362. Specifically, the three-way valve 362 includes a first valve port, a second valve port and a third valve port. The first valve port is connected to the outlet of the first water-gas separator 32, the second valve port is connected to the first anode circulation pipeline 33, and the third valve port is connected to the second anode circulation pipeline 34.

[0059] It is understandable that after the water is removed by the condenser 31 and the first water-gas separator 32, the temperature of the anode tail gas of the first-stage stack 1 is reduced. In order to ensure the efficiency of the second-stage stack 2, it is necessary to heat the anode tail gas of the first-stage stack 1 after the water is removed. In this embodiment, a circulation preheater is provided in the first anode circulation pipeline 33 to heat the gas in the first anode circulation pipeline 33 before passing it into the anode inlet of the second-stage stack 2.

[0060] Optionally, the circulating preheater includes a circulating heat exchanger 331, and the circulating heat exchanger 331 can heat the gas in the first anode circulation pipeline 33 through the anode tail gas of the first-stage fuel cell stack 1. The anode tail gas of the first-stage fuel cell stack 1 provides heat to heat the gas in the first anode circulation pipeline 33, which makes it easier to match the flow rate and temperature in design and reduces energy consumption.

[0061] Exemplarily, the circulating heat exchanger 331 includes a circulating high-temperature flow channel 3311 and a circulating low-temperature flow channel 3312, one end of the circulating high-temperature flow channel 3311 is connected to the anode outlet of the first-stage fuel cell stack 1, and the other end is connected to the inlet of the condenser 31; the circulating low-temperature flow channel 3312 is connected in series with the first anode circulation pipeline 33.

[0062] It should be noted that the liquid water separated by the first water-gas separator 32 is stored in the first water-gas separator 32 , so that the fuel cell does not need to be supplied with water from the outside.

[0063] It is understandable that the cooling temperature of the condenser 31 can be regulated by controlling the temperature and flow rate of the cooling medium of the condenser 31 .

[0064] In this embodiment, the cooling medium used by the condenser 31 is the liquid water in the first water-gas separator 32, which is beneficial to reducing the energy consumption and cost of the fuel cell fuel circulation device. Of course, in other embodiments, the cooling medium used by the condenser 31 can also be an externally supplied coolant, or a cathode gas in a low-temperature initial state, or an anode gas in a low-temperature initial state.

[0065] Optionally, the fuel cell fuel circulation device further includes a water supply pipeline 37, through which the liquid water separated by the first water-gas separator 32 can enter the first anode circulation pipeline 33, and the circulation preheater can convert the liquid water entering the first anode circulation pipeline 33 into water vapor. This arrangement facilitates the adjustment of the oxygen-carbon ratio of the fuel entering the secondary stack 2.

[0066] In this embodiment, one end of the water supply pipeline 37 is connected to the water outlet of the first water-gas separator 32 , and the other end is connected to the circulating low-temperature flow channel 3312 .

[0067] Optionally, the water supply pipeline 37 is provided with a water pump 371 .

[0068] In this embodiment, the fuel cell fuel circulation device also includes a burner 38, which can burn the unconsumed fuel in the anode exhaust gas of the secondary fuel cell stack 2 and the oxidizing gas in the cathode exhaust gas of the secondary fuel cell stack 2. Of course, in other embodiments, the burner 38 can also utilize the cathode exhaust gas of the primary fuel cell stack 1 for combustion.

[0069] Optionally, the burner 38 is a flame burner. Of course, when the fuel concentration is low and the flame burner cannot burn stably, a flameless burner such as a catalytic or porous medium burner can also be used.

[0070] Optionally, the fuel cell fuel circulation device further includes a cathode heat exchanger, which can heat the cathode gas introduced into the primary stack 1 through a cathode preheating medium, wherein the cathode preheating medium includes the tail gas of the burner 38. The high-temperature tail gas generated by the burner 38 is used to provide heat to preheat the cathode gas, which is beneficial to reducing energy consumption and costs.

[0071] Exemplarily, the cathode heat exchanger includes a cathode high-temperature flow channel and a cathode low-temperature flow channel. The cathode high-temperature flow channel is used to introduce the high-temperature exhaust gas generated by the burner 38, and the cathode low-temperature flow channel is used to introduce the cathode gas.

[0072] Of course, in other embodiments, the cathode tail gas of the primary fuel cell stack 1 or the cathode tail gas of the secondary fuel cell stack 2 can also be used as the cathode preheating medium.

[0073] Optionally, the fuel cell fuel circulation device further includes an anode heat exchanger, which can heat the anode gas introduced into the primary stack 1 through an anode preheating medium, wherein the anode preheating medium includes the tail gas of the burner 38. The high-temperature tail gas generated by the burner 38 is used to provide heat to preheat the anode gas, thereby promoting the reforming reaction of the reformer 351, which is conducive to reducing energy consumption and costs.

[0074] Exemplarily, the anode heat exchanger includes an anode high-temperature flow channel and an anode low-temperature flow channel. The anode high-temperature flow channel is used to introduce the high-temperature exhaust gas generated by the burner 38, and the anode low-temperature flow channel is used to introduce the anode gas.

[0075] Of course, in other embodiments, the preheated cathode gas, the cathode tail gas of the first-stage fuel cell stack 1 or the cathode tail gas of the second-stage fuel cell stack 2 can also be used as the anode preheating medium.

[0076] Optionally, the fuel cell fuel circulation device further includes a second water-gas separator 391 , the inlet of the second water-gas separator 391 is used to be connected to the anode outlet of the secondary fuel cell stack 2 , and the outlet of the second water-gas separator 391 is connected to the burner 38 .

[0077] Optionally, the fuel cell fuel circulation device further includes a carbon dioxide collector 392 , which is disposed between the gas outlet of the second water-gas separator 391 and the burner 38 .

[0078] After being used in a two-stage fuel cell stack, the fuel is basically converted into water and carbon dioxide. After removing water, the concentration of carbon dioxide is higher, which is more conducive to separating high-purity carbon dioxide.

[0079] After the water and carbon dioxide in the anode tail gas of the secondary fuel cell stack 2 are separated, the gas that inhibits combustion is reduced, which is beneficial to the stable combustion of the burner 38.

[0080] In this embodiment, the fuel cell fuel circulation device further includes a first cathode gas supply pipeline 3101 , and the first cathode gas supply pipeline 3101 is connected to the cathode inlet of the first-stage fuel cell stack 1 .

[0081] Furthermore, the fuel cell fuel circulation device also includes a first cathode circulation pipeline 3102, one end of the first cathode circulation pipeline 3102 is connected to the cathode outlet of the first-level fuel cell stack 1, and the other end is connected to the cathode inlet of the second-level fuel cell stack 2, so as to pass the cathode exhaust gas of the first-level fuel cell stack 1 into the second-level fuel cell stack 2 for secondary utilization, which is beneficial to improving the power generation efficiency of the fuel cell.

[0082] Furthermore, the fuel cell fuel circulation device also includes a cathode exhaust pipeline 3103, one end of which is connected to the cathode outlet of the secondary fuel cell stack 2, and the other end is connected to the burner 38, so as to pass the cathode exhaust gas of the secondary fuel cell stack 2 into the burner 38 for combustion.

[0083] Alternatively, if Figure 4 As shown, the fuel cell fuel circulation device also includes a second cathode circulation pipeline 3104, one end of the second cathode circulation pipeline 3104 is connected to the cathode outlet of the first-stage fuel cell stack 1, and the other end is connected to the cathode inlet of the first-stage fuel cell stack 1.

[0084] Furthermore, the fuel cell fuel circulation device also includes a third cathode circulation pipeline 3105, one end of the third cathode circulation pipeline 3105 is connected to the cathode outlet of the secondary fuel cell stack 2, and the other end is connected to the cathode inlet of the primary fuel cell stack 1.

[0085] Such an arrangement can further increase the circulation rate of the cathode gas and improve the power generation efficiency of the fuel cell.

[0086] Furthermore, the first cathode gas supply pipeline 3101 is provided with an ejector, and the second cathode circulation pipeline 3104 and the third cathode circulation pipeline 3105 are both connected to the ejector.

[0087] Optionally, the second cathode circulation pipeline 3104 is provided with a first control valve, and the first control valve is a switch valve or a flow valve.

[0088] Optionally, the third cathode circulation pipeline 3105 is provided with a second control valve, and the second control valve is a switch valve or a flow valve.

[0089] Of course, in other embodiments, such as Figure 5As shown, it can also be configured as follows: the fuel cell fuel circulation device also includes a second cathode gas supply pipeline 3106, one end of the second cathode gas supply pipeline 3106 is connected to the first cathode gas supply pipeline 3101, and the other end is connected to the cathode inlet of the secondary battery stack 2; and one end of the cathode exhaust pipeline 3103 is respectively connected to the cathode outlet of the first battery stack 1 and the cathode outlet of the secondary battery stack 2, and the other end is connected to the burner 38, so that the cathode exhaust gas of the first battery stack 1 and the secondary battery stack 2 can both be passed into the burner 38 for combustion.

[0090] For example, in this embodiment, the working principle of the fuel cell fuel circulation device is:

[0091] The fuel and water vapor undergo a reforming reaction in the reformer 351, and the generated hydrogen-rich gas enters the primary stack 1 to generate electricity. The anode tail gas of the primary stack 1 enters the circulating heat exchanger 331 to heat the gas in the first anode circulation pipeline 33 and cool the anode tail gas of the primary stack 1 itself. Then, the anode tail gas of the primary stack 1 is further cooled to below the water vapor dew point in the condenser 31 to liquefy the water vapor in the anode tail gas of the primary stack 1, and the separated liquid water is stored in the first water-gas separator 32, and the separated gas enters the hydrogen separator 361. The pure hydrogen separated by the hydrogen separator 361 enters the second anode circulation pipeline 34 and returns to the inlet of the reformer 351 under the pumping action of the fuel circulation pump 341. The separated gases other than hydrogen, such as carbon monoxide, methane, etc., enter the first anode circulation pipeline 33, and enter the secondary stack 2 for power generation after being heated by the circulating heat exchanger 331.

[0092] The water pump 371 can extract a small amount of liquid water from the first water-gas separator 32 and inject it into the circulating low-temperature flow channel 3312 of the circulating heat exchanger 331, so as to absorb heat from the anode tail gas of the first-level fuel cell stack 1 in the circulating high-temperature flow channel 3311 to complete the evaporation phase change process, thereby ensuring that the oxygen-carbon ratio of the gas entering the second-level fuel cell stack 2 is maintained at an appropriate level.

[0093] After the anode tail gas of the secondary fuel cell stack 2 passes through the second water-gas separator 391 to separate the liquid water, the remaining gas enters the carbon dioxide collector 392 to separate the high-purity carbon dioxide, and the remaining gas enters the burner 38 for combustion.

[0094] Embodiment 2

[0095] like Figure 6-9As shown, the difference between this embodiment and embodiment one is that the fuel of the fuel cell of this embodiment is polycarbon. Since the use of polycarbon fuel requires more water vapor or carbon dioxide for reforming reaction, the connection method of the second anode circulation pipeline 34 in this embodiment is different from that in embodiment one, specifically, one end of the second anode circulation pipeline 34 is connected to the anode outlet of the first-stage fuel cell stack 1, and the other end is connected to the anode inlet of the first-stage fuel cell stack 1.

[0096] The fuel circulation device of this embodiment divides the anode tail gas of the first-stage fuel cell stack 1 into two parts, one part of which is directly sent back to the anode inlet of the first-stage fuel cell stack 1 through the second anode circulation pipeline 34 for recycling, thereby improving the fuel utilization rate. Since the anode tail gas of the first-stage fuel cell stack 1 contains a large amount of water vapor and carbon dioxide, it is suitable for reforming high-carbon fuels such as diesel and gasoline; the other part is dehydrated by the condenser 31 and the first water-gas separator 32, so that the concentration of fuels such as hydrogen, carbon monoxide, and methane therein is increased, and then passed into the second-stage fuel cell stack 2 through the first anode circulation pipeline 33 for reuse, which is beneficial to improving the voltage efficiency of the second-stage stack.

[0097] For example, in this embodiment, the working principle of the fuel cell fuel circulation device is:

[0098] The fuel and water vapor undergo a reforming reaction in the reformer 351, and the generated hydrogen-rich gas enters the first-stage stack 1 to generate electricity. The anode tail gas of the first-stage stack 1 is divided into two parts, one of which enters the second anode circulation pipeline 34 and returns to the inlet of the reformer 351 under the pumping action of the fuel circulation pump 341; the other part enters the circulation heat exchanger 331 to heat the gas in the first anode circulation pipeline 33 and cool the anode tail gas of this part of the first-stage stack 1. Then, the anode tail gas of this part of the first-stage stack 1 is further cooled to below the water vapor dew point in the condenser 31, so that the water vapor in the anode tail gas of this part of the first-stage stack 1 is liquefied, and the separated liquid water is stored in the first water-gas separator 32, and the separated gases such as carbon monoxide, methane, etc. enter the first anode circulation pipeline 33, and enter the second-stage stack 2 for power generation after being heated by the circulation heat exchanger 331.

[0099] The water pump 371 can extract a small amount of liquid water from the first water-gas separator 32 and inject it into the circulating low-temperature flow channel 3312 of the circulating heat exchanger 331, so as to absorb heat from the anode tail gas of the first-level fuel cell stack 1 in the circulating high-temperature flow channel 3311 to complete the evaporation phase change process, thereby ensuring that the oxygen-carbon ratio of the gas entering the second-level fuel cell stack 2 is maintained at an appropriate level.

[0100] After the anode tail gas of the secondary fuel cell stack 2 passes through the second water-gas separator 391 to separate the liquid water, the remaining gas enters the carbon dioxide collector 392 to separate the high-purity carbon dioxide, and the remaining gas enters the burner 38 for combustion.

[0101] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A fuel cell fuel circulation device, characterized in that: The fuel cell comprises a primary stack (1) and a secondary stack (2); the fuel cell fuel circulation device comprises: A condenser (31), wherein an inlet of the condenser (31) is used to be connected to an anode outlet of the first-stage fuel cell stack (1); a first water-gas separator (32), wherein an inlet of the first water-gas separator (32) is connected to an outlet of the condenser (31); A first anode circulation pipeline (33), one end of the first anode circulation pipeline (33) being connected to the gas outlet of the first water-gas separator (32), and the other end of the first anode circulation pipeline (33) being connected to the anode inlet of the secondary fuel cell stack (2); A second anode circulation pipeline (34), one end of which is connected to the gas outlet of the first water-gas separator (32) or is used to be connected to the anode outlet of the first-stage fuel cell stack (1), and the other end is used to be connected to the anode inlet of the first-stage fuel cell stack (1).

2. The fuel cell fuel circulation device according to claim 1, characterized in that: When one end of the second anode circulation pipeline (34) is connected to the gas outlet of the first water-gas separator (32), a hydrogen separator (361) is provided between the gas outlet of the first water-gas separator (32), the second anode circulation pipeline (34) and the first anode circulation pipeline (33), and the hydrogen separator (361) comprises a separation inlet, a hydrogen outlet for outputting hydrogen and a gas outlet for outputting other gases except hydrogen, the separation inlet is connected to the gas outlet of the first water-gas separator (32), the hydrogen outlet is connected to the second anode circulation pipeline (34), and the gas outlet is connected to the first anode circulation pipeline (33).

3. The fuel cell fuel circulation device according to claim 1, characterized in that: The first anode circulation pipeline (33) is provided with a circulation preheater.

4. The fuel cell fuel circulation device according to claim 3, characterized in that: The circulating preheater comprises a circulating heat exchanger (331), and the gas in the first anode circulation pipeline (33) and the anode tail gas of the first-stage fuel cell stack (1) can exchange heat through the circulating heat exchanger (331).

5. The fuel cell fuel circulation device according to claim 3, characterized in that: The fuel cell fuel circulation device also includes a water replenishment pipeline (37), through which the liquid water separated by the first water-gas separator (32) can enter the first anode circulation pipeline (33), and the circulation preheater can convert the liquid water entering the first anode circulation pipeline (33) into water vapor.

6. The fuel cell fuel circulation device according to claim 1, characterized in that: The fuel cell fuel circulation device also includes a burner (38), which is capable of burning the anode tail gas of the secondary stack (2), and / or the cathode tail gas of the secondary stack (2), and / or the cathode tail gas of the primary stack (1).

7. The fuel cell fuel circulation device according to claim 6, characterized in that: The fuel cell fuel circulation device also includes a second water-gas separator (391), the inlet of the second water-gas separator (391) is used to be connected to the anode outlet of the secondary fuel cell stack (2), and the outlet of the second water-gas separator (391) is connected to the burner (38).

8. The fuel cell fuel circulation device according to claim 7, characterized in that: The fuel cell fuel circulation device further comprises a carbon dioxide collector (392), wherein the carbon dioxide collector (392) is arranged between the gas outlet of the second water-gas separator (391) and the burner (38).

9. The fuel cell fuel circulation device according to claim 6, characterized in that: The fuel cell fuel circulation device further comprises a cathode heat exchanger, wherein the cathode heat exchanger is capable of heating the cathode gas introduced into the primary stack (1) through a cathode preheating medium, wherein the cathode preheating medium comprises the tail gas of the burner (38), the cathode tail gas of the primary stack (1) or the cathode tail gas of the secondary stack (2); The fuel cell fuel circulation device also includes an anode heat exchanger, which can heat the anode gas introduced into the primary stack (1) through an anode preheating medium, and the anode preheating medium includes the exhaust gas of the burner (38), the preheated cathode gas, the cathode exhaust gas of the primary stack (1) or the cathode exhaust gas of the secondary stack (2).

10. The fuel cell fuel circulation device according to claim 1, characterized in that: The fuel cell fuel circulation device further comprises a first cathode circulation pipeline (3102), one end of the first cathode circulation pipeline (3102) being connected to the cathode outlet of the first-stage fuel cell stack (1), and the other end of the first cathode circulation pipeline (3102) being connected to the cathode inlet of the second-stage fuel cell stack (2); The fuel cell fuel circulation device further comprises a second cathode circulation pipeline (3104), one end of the second cathode circulation pipeline (3104) being connected to the cathode outlet of the first-stage fuel cell stack (1), and the other end of the second cathode circulation pipeline (3104) being connected to the cathode inlet of the first-stage fuel cell stack (1); The fuel cell fuel circulation device also includes a third cathode circulation pipeline (3105), one end of which is connected to the cathode outlet of the secondary fuel cell stack (2), and the other end is connected to the cathode inlet of the primary fuel cell stack (1).

11. A fuel cell, characterized in that It comprises a primary stack (1), a secondary stack (2) and a fuel cell fuel circulation device as claimed in any one of claims 1 to 10, wherein the inlet of the condenser (31) is connected to the anode outlet of the primary stack (1), one end of the first anode circulation pipeline (33) is connected to the gas outlet of the first water-gas separator (32), and the other end is connected to the anode inlet of the secondary stack (2), one end of the second anode circulation pipeline (34) is connected to the gas outlet of the first water-gas separator (32) or to the anode outlet of the primary stack (1), and the other end is connected to the anode inlet of the primary stack (1).

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