A fuel cell hydrogen circulation system

Abstract

The utility model discloses a kind of fuel cell hydrogen circulation systems, including hydrogen fuel cell, steam-water separator, first eductor, second eductor, third eductor, first flow regulating valve, second flow regulating valve and third flow regulating valve, hydrogen fuel cell's hydrogen road export, steam-water separator's import, steam-water separator's gas export, first eductor's eduction fluid import, first eductor's export, second eductor's eduction fluid import, second eductor's export, third eductor's eduction fluid import, third eductor's export, hydrogen fuel cell's hydrogen road import are sequentially communicated;The circulation system of the utility model is high in efficiency, low in cost, low in noise, simple structure, by the limitation of the connecting position of three eductor, the effect of large circulation flow, large pressure rise can be realized.

Description

Technical Field

[0001] This utility model relates to a fuel cell hydrogen circulation system. Background Technology

[0002] In recent years, the new energy industry has continued to develop rapidly, and hydrogen fuel cells and their systems have gradually gained public recognition for their advantages such as zero emissions, short refueling time, and wide application. The basic structure of a fuel cell consists of a hydrogen circuit, an air circuit, and a water circuit. The water circuit provides the necessary heat dissipation or heating function for the fuel cell, the air circuit provides the compressed air required for the reaction, and the hydrogen circuit provides the hydrogen required for the fuel cell reaction. For the hydrogen circulation system of a fuel cell, the higher the fuel cell power, the greater the required flow rate and pressure rise of the circulation system. Existing technologies have very limited means to increase the circulation flow rate and improve the pressure rise. Most manufacturers choose to equip the fuel cell system with a circulation pump, which increases system cost, reduces system efficiency, and increases operating noise—a necessary but unavoidable choice. Furthermore, ejector methods are difficult to achieve high pressure rises at large circulation flow rates; for example, at hydrogen circulation flow rates above 3000 slpm, it is difficult to break through the 0.2 bar pressure rise barrier. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the problems of low efficiency, high cost and high noise when using circulation pumps in existing fuel cell hydrogen circulation systems, and the difficulty in achieving high pressure rise under large circulation flow when using ejectors. The present utility model provides a fuel cell hydrogen circulation system that can be independently controlled, has low noise, simple structure and low cost.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] This utility model discloses a fuel cell hydrogen circulation system, which includes: a hydrogen fuel cell, a gas-water separator, a first ejector, a second ejector, a third ejector, a first flow regulating valve, a second flow regulating valve, and a third flow regulating valve;

[0006] The hydrogen outlet of the hydrogen fuel cell, the inlet of the gas-water separator, the gas outlet of the gas-water separator, the ejector fluid inlet of the first ejector, the outlet of the first ejector, the ejector fluid inlet of the second ejector, the outlet of the second ejector, the ejector fluid inlet of the third ejector, the outlet of the third ejector, and the hydrogen inlet of the hydrogen fuel cell are connected in sequence.

[0007] The nozzle outlet diameter of the first ejector is d1, and the diameter of the mixing section is dmix1. The nozzle outlet diameter of the second ejector is d2, and the diameter of the mixing section is dmix2. The nozzle outlet diameter of the third ejector is d3, and the diameter of the mixing section is dmix3. d3 > d1 > d2, dmix3 > dmix2 > dmix1, so that the flow rate of the fluid ejected by the second ejector, the first ejector, and the third ejector gradually increases.

[0008] The first flow regulating valve is installed on the working fluid inlet of the first ejector and is used to regulate the flow rate of the working fluid inlet of the first ejector.

[0009] The second flow regulating valve is installed on the working fluid inlet of the second ejector and is used to regulate the flow rate of the working fluid inlet of the second ejector.

[0010] The third flow regulating valve is installed on the working fluid inlet of the third ejector and is used to regulate the flow rate of the working fluid inlet of the third ejector.

[0011] In this utility model, the structures of the first ejector, the second ejector, and the third ejector can all be conventional in the art. Specifically, the first ejector includes a nozzle, a converging section, a mixing section, and a diffuser section connected in sequence. One end of the nozzle is provided with the working fluid inlet, and the other end is connected to the converging section. The ejector fluid inlet is provided on the side of the converging section and communicates with the converging section.

[0012] The second ejector and the third ejector have the same structure as the first ejector.

[0013] In this invention, the ratio of dmix1, dmix2 and dmix3 is preferably 1:(1.2~1.75):(1.8~2.71), and more preferably 1:(1.3~1.6):(1.8~2.2).

[0014] In this invention, the ratio of d1, d2 and d3 is preferably (1.2~1.9):1:(2.0~2.8), and more preferably (1.4~1.8):1:(2.1~2.5).

[0015] In this invention, the first, second, and third ejectors have different dimensions, which leads to a gradual increase in the flow rate of the ejected fluid by the second, first, and third ejectors. Generally, the larger the outlet diameter of the ejector nozzle, the larger the dimensions of other parts of the ejector (i.e., the diameter and length of the diffuser section, the length of the mixing section, and the diameter of the ejected fluid inlet).

[0016] In a specific embodiment of this utility model, the diameter and length of the diffuser section of the first ejector are both greater than the diameter and length of the diffuser section of the second ejector, and the diameter and length of the diffuser section of the third ejector are both greater than the diameter and length of the diffuser section of the first ejector; the length of the mixing section of the first ejector is greater than the length of the mixing section of the second ejector and less than the length of the mixing section of the third ejector; the diameter of the ejector fluid inlet of the first ejector is greater than the diameter of the ejector fluid inlet of the second ejector and less than the diameter of the ejector fluid inlet of the third ejector.

[0017] In this invention, preferably, the ejector fluid inlet of the first ejector is connected to the gas outlet of the gas-water separator via a connecting flange. Compared to the traditional method of connecting the ejector and the gas-water separator via pipelines, this solution directly integrates the ejector onto the gas-water separator, reducing the gas path, lowering resistance, and indirectly increasing the circulation flow rate.

[0018] In this invention, the outlet of the steam-water separator is generally equipped with a drain valve.

[0019] In this invention, preferably, a first feed pipe is provided on the working fluid inlet of the first ejector, the first flow regulating valve is provided on the first feed pipe, and the first feed pipe is also connected to a hydrogen storage tank.

[0020] In this invention, preferably, a second feed pipe is provided on the working fluid inlet of the second ejector, a second flow regulating valve is provided on the second feed pipe, and the second feed pipe is also connected to a hydrogen storage tank.

[0021] In this invention, preferably, a third feed pipe is provided on the working fluid inlet of the third ejector, a third flow regulating valve is provided on the third feed pipe, and the third feed pipe is also connected to a hydrogen storage tank.

[0022] When the aforementioned fuel cell hydrogen recirculation system is in operation, its operation method includes the following steps:

[0023] When the operating power of the hydrogen fuel cell is the first preset power P1, the second flow regulating valve opens, and the first flow regulating valve and the third flow regulating valve are both closed, and the second ejector is activated.

[0024] When the operating power of the hydrogen fuel cell is the second preset power P2, both the first flow regulating valve and the second flow regulating valve are open, the third flow regulating valve is closed, and the first ejector and the second ejector are operated.

[0025] When the operating power of the hydrogen fuel cell is a third preset power P3, all of the first flow regulating valve, the second flow regulating valve and the third flow regulating valve are opened, and all of the first ejector, the second ejector and the third ejector are in operation;

[0026] P1< P2< P3.

[0027] In the present utility model, preferably, 0<P1≤20%P; or 15%P<P2≤45%P; or 40%P<P3≤100%P, where P denotes the rated power of the hydrogen fuel cell.

[0028] More preferably, when the operating power of the hydrogen fuel cell rises from low power to high power, 0<P1≤20%P, 20%P<P2≤45%P, 45%P<P3≤100%P; for example, when the power at the previous moment is 20%P and the current power is 30%P, the switching nodes of the three flow regulating valves are 20%P and 45%P.

[0029] When the operating power of the hydrogen fuel cell drops from high power to low power, 0<P1≤15%P, 15%P<P2≤40%P, 40%P<P3≤100%P; for example, when the power at the previous moment is 30%P and the current power is 20%P, the switching nodes of the three flow regulating valves are 15%P and 40%P.

[0030] The positive progressive effects of the present utility model lie in:

[0031] (1) The circulation system of the present utility model has high efficiency, low cost, low noise and a simple structure. Specifically: through the arrangement of ejectors with three different ejector flow specifications (i.e., the first ejector, the second ejector, and the third ejector), each of the three ejectors can be independently controlled, and the activation and deactivation of the three ejectors can be flexibly adjusted according to actual power requirements, so as to improve the efficiency of the circulation system and reduce the cost;

[0032] (2) By limiting the connection positions of the three ejectors, this utility model can achieve a large circulation flow rate and a large pressure rise, making it comparable to or even surpassing the performance of a circulation pump. Specifically: the first and second ejectors serve the third ejector. The third ejector itself will generate a large circulation flow rate under a large activation flow rate. However, if the resistance of the other components in the series circuit is high and a large pressure rise is generated, the circulation flow rate will be sharply reduced, restricting the operation of the system. When the first and second ejectors are running, they provide additional kinetic energy for the suction flow rate of the third ejector and help the third ejector overcome most of the resistance of the circulation path. By placing the first ejector, whose flow rate is in the middle, at the gas outlet of the gas-water separator, a higher suction flow rate can be obtained, and the pressure rise and flow rate of the entire system can be improved in a balanced manner. In a specific embodiment of this utility model, the hydrogen circulation flow rate can reach a pressure rise of more than 0.45 bar at 3000 slpm. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the hydrogen circulation system of the fuel cell described in an embodiment of the present invention.

[0034] Figure 2 This is a schematic diagram of the ejector structure described in an embodiment of the present invention, where d represents the diameter of the ejector nozzle outlet and dmix represents the diameter of the mixing section.

[0035] Explanation of the labels in the diagram:

[0036] 1-Hydrogen fuel cell, 2-Gas-water separator, 3-First ejector, 4-Second ejector, 5-Third ejector, 6-First flow regulating valve, 7-Second flow regulating valve, 8-Third flow regulating valve, 9-Drain valve;

[0037] A - Nozzle, B - Contraction section, C - Mixing section, D - Diffusion section, E - Working fluid inlet, F - Ejector fluid inlet. Detailed Implementation

[0038] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the embodiments described herein.

[0039] Example 1

[0040] This embodiment discloses a fuel cell hydrogen circulation system, which includes: a hydrogen fuel cell 1, a gas-water separator 2, a first ejector 3, a second ejector 4, a third ejector 5, a first flow regulating valve 6, a second flow regulating valve 7, and a third flow regulating valve 8.

[0041] The hydrogen outlet of the hydrogen fuel cell 1, the inlet of the gas-water separator 2, the gas outlet of the gas-water separator 2, the ejector fluid inlet of the first ejector 3, the outlet of the first ejector 3, the ejector fluid inlet of the second ejector 4, the outlet of the second ejector 4, the ejector fluid inlet of the third ejector 5, the outlet of the third ejector 5, and the hydrogen inlet of the hydrogen fuel cell 1 are connected in sequence.

[0042] In this embodiment, the first ejector 3 includes a nozzle A, a contraction section B, a mixing section C, and a diffuser section D connected in sequence. One end of the nozzle A is provided with a working fluid inlet E, and the other end is connected to the contraction section B. The ejector fluid inlet F is provided on the side of the contraction section B and communicates with the contraction section B. The structures of the second ejector 4 and the third ejector 5 are the same as those of the first ejector 3.

[0043] The nozzle outlet diameter of the first ejector 3 is d1, and the diameter of the mixing section is dmix1. The nozzle outlet diameter of the second ejector 4 is d2, and the diameter of the mixing section is dmix2. The nozzle outlet diameter of the third ejector 5 is d3, and the diameter of the mixing section is dmix3. d3 > d1 > d2, dmix3 > dmix2 > dmix1, so that the flow rate of the fluid ejected by the second ejector 4, the first ejector 3, and the third ejector 5 gradually increases. Specifically, in this embodiment, the ratio of dmix1, dmix2, and dmix3 is 1:(1.3~1.6):(1.8~2.2), and the ratio of d1, d2, and d3 is (1.4~1.8):1:(2.1~2.5). The diameter and length of the diffuser section D of the first ejector 3 are both greater than those of the diffuser section D of the second ejector 4, and the diameter and length of the diffuser section D of the third ejector 5 are both greater than those of the diffuser section D of the first ejector 3; the length of the mixing section C of the first ejector 3 is greater than that of the mixing section C of the second ejector 4 and less than that of the mixing section C of the third ejector 5; the diameter of the ejector fluid inlet F of the first ejector 3 is greater than that of the ejector fluid inlet F of the second ejector 4 and less than that of the ejector fluid inlet F of the third ejector 5.

[0044] The first flow regulating valve 6 is installed on the working fluid inlet of the first ejector 3 and is used to regulate the flow rate of the working fluid inlet of the first ejector 3.

[0045] The second flow regulating valve 7 is installed on the working fluid inlet of the second ejector 4 and is used to regulate the flow rate of the working fluid inlet of the second ejector 4.

[0046] The third flow regulating valve 8 is installed on the working fluid inlet of the third ejector 5 and is used to regulate the flow rate of the working fluid inlet of the third ejector 5.

[0047] The outlet of the steam-water separator 2 is equipped with a drain valve 9.

[0048] In this embodiment, the ejection fluid inlet of the first ejector 3 is connected to the gas outlet of the steam-water separator via a connecting flange.

[0049] In this embodiment, a first feed pipe is disposed at the working fluid inlet of the first ejector 3, a first flow regulating valve 6 is disposed on the first feed pipe, and the first feed pipe is further communicated with the hydrogen storage tank; a second feed pipe is disposed at the working fluid inlet of the second ejector 4, a second flow regulating valve 7 is disposed on the second feed pipe, and the second feed pipe is further communicated with the hydrogen storage tank; a third feed pipe is disposed at the working fluid inlet of the third ejector 5, a third flow regulating valve 8 is disposed on the third feed pipe, and the third feed pipe is further communicated with the hydrogen storage tank.

[0050] Embodiment 2

[0051] This embodiment discloses an operation method of the fuel cell hydrogen circulation system in Embodiment 1, which includes the following steps:

[0052] When the operating power of the hydrogen fuel cell 1 is a first preset power P1, the second flow regulating valve 7 is opened, the first flow regulating valve 6 and the third flow regulating valve 8 are both closed, and the second ejector 4 is operated;

[0053] When the operating power of the hydrogen fuel cell 1 is a second preset power P2, the first flow regulating valve 6 and the second flow regulating valve 7 are both opened, the third flow regulating valve 8 is closed, and the first ejector 3 and the second ejector 4 are operated;

[0054] When the operating power of the hydrogen fuel cell 1 is a third preset power P3, the first flow regulating valve 6, the second flow regulating valve 7 and the third flow regulating valve 8 are all opened, and the first ejector 3, the second ejector 4 and the third ejector 5 are all operated;

[0055] In this embodiment, when the operating power of the hydrogen fuel cell 1 increases from low power to high power, 0<P1≤20%P, 20%P<P2≤45%P, 45%P<P3≤100%P; when the operating power of the hydrogen fuel cell 1 decreases from high power to low power, 0<P1≤15%P, 15%P<P2≤40%P, 40%P<P3≤100%P, where P represents the rated power of the hydrogen fuel cell 1. In this embodiment, P=250-300kw.

[0056] The results show that: under the hydrogen circulation flow rate of 3000slpm, this embodiment achieves a pressure rise effect of more than 0.45bar.

[0057] Comparative Example 1

[0058] The fuel cell hydrogen circulation system of this comparative example is basically the same as that of Embodiment 1, and the difference lies in:

[0059] Replace the positions of the first ejector 3 and the second ejector 4, that is: the hydrogen outlet of the hydrogen fuel cell 1, the inlet of the gas-water separator 2, the gas outlet of the gas-water separator 2, the ejector fluid inlet of the second ejector 4, the outlet of the second ejector 4, the ejector fluid inlet of the first ejector 3, the outlet of the first ejector 3, the ejector fluid inlet of the third ejector 5, the outlet of the third ejector 5, and the hydrogen inlet of the hydrogen fuel cell 1 are connected in sequence; and the ratio of dmix2, dmix1 and dmix3 is 1:(1.3~1.6):(1.8~2.2), so that the three ejectors are arranged in order of increasing size along the hydrogen flow direction.

[0060] The hydrogen fuel cell 1 was operated using the operating method of the hydrogen circulation system described in Example 2, and the rated power P of the hydrogen fuel cell 1 was the same as that in Example 2.

[0061] The results showed that the pressure rise in this comparative example was 0.3~0.38 bar at a hydrogen circulation flow rate of 3000 slpm.

[0062] Comparative Example 2

[0063] The hydrogen circulation system of the fuel cell in this comparative example is basically the same as that in Example 1, except that the ratio of the nozzle diameters d1, d2 and d3 in this comparative example is 1:1:1, and the ratio of dmix1, dmix2 and dmix3 is 1:1:1.

[0064] The hydrogen fuel cell 1 was operated using the operating method of the hydrogen circulation system described in Example 2, and the rated power P of the hydrogen fuel cell 1 was the same as that in Example 2.

[0065] The results showed that the pressure rise in this comparative example was 0.25~0.31 bar at a hydrogen circulation flow rate of 3000 slpm.

[0066] Comparative Example 3

[0067] The hydrogen circulation system of the fuel cell in this comparative example is basically the same as that in Example 1, except that: this comparative example does not have a second ejector 4 and a second flow regulating valve 7. That is, the hydrogen outlet of the hydrogen fuel cell 1, the inlet of the gas-water separator 2, the gas outlet of the gas-water separator 2, the ejector fluid inlet of the first ejector 3, the outlet of the first ejector 3, the ejector fluid inlet of the third ejector 5, the outlet of the third ejector 5, and the hydrogen inlet of the hydrogen fuel cell 1 are connected in sequence.

[0068] The operation method of the fuel cell hydrogen cycle system in this comparative example includes the following steps:

[0069] When the operating power of the hydrogen fuel cell 1 is the second preset power P2, the first flow regulating valve 6 opens and the third flow regulating valve 8 closes, and the first ejector 3 is activated.

[0070] When the operating power of the hydrogen fuel cell 1 is at the third preset power P3, both the first flow regulating valve 6 and the third flow regulating valve 8 are open, and both the first ejector 3 and the third ejector 5 are in operation;

[0071] In this embodiment, when the operating power of the hydrogen fuel cell 1 rises from low power to high power, 0<P2≤45%P, 45%P<P3≤100%P; when the operating power of the hydrogen fuel cell 1 drops from high power to low power, 0<P2≤40%P, 40%P<P3≤100%P, where P is the same as that in Embodiment 2.

[0072] The results show that: in this comparative example, under a hydrogen circulation flow rate of 3000slpm, the pressure rise is 0.25~0.34bar.

[0073] Although the specific embodiments of the present utility model have been described above, those skilled in the art should understand that these are only illustrative, and the protection scope of the present utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present utility model, and all such changes and modifications shall fall within the protection scope of the present utility model.

Claims

1. A fuel cell hydrogen recirculation system, characterized in that, It includes: Hydrogen fuel cell, gas-liquid separator, first ejector, second ejector, third ejector, first flow control valve, second flow control valve and third flow control valve; The hydrogen outlet of the hydrogen fuel cell, the inlet of the gas-water separator, the gas outlet of the gas-water separator, the ejector fluid inlet of the first ejector, the outlet of the first ejector, the ejector fluid inlet of the second ejector, the outlet of the second ejector, the ejector fluid inlet of the third ejector, the outlet of the third ejector, and the hydrogen inlet of the hydrogen fuel cell are connected in sequence. The nozzle outlet diameter of the first ejector is d1, and the diameter of the mixing section is dmix1. The nozzle outlet diameter of the second ejector is d2, and the diameter of the mixing section is dmix2. The nozzle outlet diameter of the third ejector is d3, and the diameter of the mixing section is dmix3. d3 > d1 > d2, dmix3 > dmix2 > dmix1, so that the flow rate of the fluid ejected by the second ejector, the first ejector, and the third ejector gradually increases. The first flow regulating valve is installed on the working fluid inlet of the first ejector and is used to regulate the flow rate of the working fluid inlet of the first ejector. The second flow regulating valve is installed on the working fluid inlet of the second ejector and is used to regulate the flow rate of the working fluid inlet of the second ejector. The third flow regulating valve is installed on the working fluid inlet of the third ejector and is used to regulate the flow rate of the working fluid inlet of the third ejector.

2. The fuel cell hydrogen recirculation system as described in claim 1, characterized in that, The ratio of dmix1, dmix2 and dmix3 is 1:(1.2~1.75):(1.8~2.71).

3. The fuel cell hydrogen recirculation system as described in claim 2, characterized in that, The ratio of dmix1, dmix2 and dmix3 is 1:(1.3~1.6):(1.8~2.2).

4. The fuel cell hydrogen recirculation system as described in claim 1, characterized in that, The ratio of d1, d2 and d3 is (1.2~1.9):1:(2.0~2.8).

5. The fuel cell hydrogen recirculation system as described in claim 4, characterized in that, The ratio of d1, d2 and d3 is (1.4~1.8):1:(2.1~2.5).

6. The fuel cell hydrogen recirculation system as described in claim 1, characterized in that, The first ejector includes a nozzle, a converging section, a mixing section, and a diffuser connected in sequence. One end of the nozzle is provided with the working fluid inlet, and the other end is connected to the converging section. The ejector fluid inlet is located on the side of the converging section and communicates with the converging section. The second ejector and the third ejector have the same structure as the first ejector.

7. The fuel cell hydrogen recirculation system as described in claim 6, characterized in that, The diameter and length of the diffuser section of the first ejector are both greater than the diameter and length of the diffuser section of the second ejector, and the diameter and length of the diffuser section of the third ejector are both greater than the diameter and length of the diffuser section of the first ejector; the length of the mixing section of the first ejector is greater than the length of the mixing section of the second ejector and less than the length of the mixing section of the third ejector; the diameter of the ejector fluid inlet of the first ejector is greater than the diameter of the ejector fluid inlet of the second ejector and less than the diameter of the ejector fluid inlet of the third ejector.

8. The fuel cell hydrogen recirculation system as described in claim 1, characterized in that, The ejector fluid inlet of the first ejector is connected to the gas outlet of the gas-water separator via a connecting flange.

9. The fuel cell hydrogen recirculation system as described in claim 1, characterized in that, The outlet of the steam-water separator is equipped with a drain valve.

10. The fuel cell hydrogen recirculation system as described in claim 1, characterized in that, The first ejector is provided with a first feed pipe at its working fluid inlet, and the first flow regulating valve is provided on the first feed pipe. The first feed pipe is also connected to a hydrogen storage tank. And / or, a second feed pipe is provided on the working fluid inlet of the second ejector, the second flow regulating valve is provided on the second feed pipe, and the second feed pipe is also connected to a hydrogen storage tank; And / or, a third feed pipe is provided on the working fluid inlet of the third ejector, the third flow regulating valve is provided on the third feed pipe, and the third feed pipe is also connected to the hydrogen storage tank.

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