Fuel cell system water separator efficiency

Abstract

The present disclosure provides fuel cell system water separator efficiency. An apparatus for separating liquid water from a recycle gas stream in a fuel cell system includes an outer cylindrical canister. The canister includes: a side wall having an intake port; a top wall; and the bottom is provided with a water outlet port. The intake port is designed to receive an input flow from an anode side of the fuel cell system. Within the outer cylindrical canister, an inner protective tube is in fluid communication with the outlet port. The inner protection tube allows separated gas to flow to the gas outlet port while preventing liquid water from entering the gas outlet. The inner protective tube has an inlet opening for receiving the separated gas stream. The anode separation device is modified to reduce the formation of water droplets that may be entrained in the recycle gas stream.

Description

Technical Field

[0001] In at least one aspect, methods and systems for separating liquid water from recirculated gas in a fuel cell system are provided. Background Technology

[0002] In a typical fuel cell system, an anode separation (AKO) unit is used to separate water (a byproduct of chemical reactions inside the fuel cell stack) from the recirculated gas for reuse of the remaining hydrogen. Summary of the Invention

[0003] In at least one aspect, an anode separation device is provided for separating liquid water from a recirculated gas stream in a fuel cell system. The anode separation device includes an outer cylindrical canister. The outer cylindrical canister includes: a sidewall including an inlet port; a top wall including an outlet port; and a bottom wall. An outlet port is attached to either the sidewall or the bottom wall. The inlet port includes an inner surface and is configured to receive an input stream from the anode side of the fuel cell system. Inside the outer cylindrical canister, an inner protective tube is in fluid communication with the outlet port. This inner protective tube allows separated gas to flow to the outlet port while inhibiting liquid water from entering the outlet port. The inner protective tube has an inlet opening for receiving the recirculated gas stream. The anode separation device optionally includes a water separator between the inner protective tube and the outlet port, the water separator being configured to inhibit water splashing back into the inner protective tube. Advantageously, the anode separation device is modified to reduce (i.e., inhibit) the formation of water droplets that may be entrained in the recirculated gas stream.

[0004] On the other hand, an apparatus is provided for separating liquid water from a recirculated gas stream in a fuel cell system. The apparatus includes an outer cylindrical canister having: a sidewall having an inlet port; a top wall having an outlet port; and a bottom wall. An outlet port is attached to the sidewall or the bottom wall, and the inlet port includes an inner surface and is configured to receive an input stream from the anode side of the fuel cell system. An inner protective tube is positioned within the outer cylindrical canister in fluid communication with the outlet port. The inner protective tube is configured to allow the separated gas stream to reach the outlet port while preventing liquid water from being carried into the outlet port. The inner protective tube defines an inlet opening for receiving the separated gas stream. Advantageously, the ratio of a first distance from the top of the inner surface of the inlet port to the length of the inner protective tube is optimized to suppress water droplets being entrained in the recirculated gas stream. The apparatus may also include a water separator between the inner protective tube and the outlet port, the water separator being configured to prevent water splashing back into the inner protective tube.

[0005] In another aspect, an anode separation device is provided for separating liquid water from a recirculated gas stream in a fuel cell system. The anode separation device includes an outer cylindrical tank comprising: a sidewall having an inlet port; a top wall having an outlet port; and a bottom wall. The inlet port includes an inner surface and is configured to receive an input stream from the anode side of the fuel cell system. An outlet port is attached to either the sidewall or the bottom wall. The anode separation device also includes an inner protective tube assembly positioned within the outer cylindrical tank in fluid communication with the outlet port. The inner protective tube assembly includes a first inner protective tube component and a second inner protective tube component configured to cooperate to allow separated gas streams to reach the outlet port while preventing liquid water from being carried into the outlet port. Optionally, the anode separation device includes a water separator between the inner protective tube and the outlet port, the water separator being configured to suppress water splashing back into the inner protective tube assembly.

[0006] In at least one aspect, an anode separation device is provided for separating liquid water from a recirculated gas stream in a fuel cell system. The anode separation device includes an outer cylindrical canister. The outer cylindrical canister includes: a sidewall including an inlet port; a top wall including an outlet port; and a bottom wall. An outlet port is attached to either the sidewall or the bottom wall. The inlet port includes an inner surface and is configured to receive an input stream from the anode side of the fuel cell system. Inside the outer cylindrical canister, an inner protective tube is in fluid communication with the outlet port. This inner protective tube allows separated gas to flow to the outlet port while inhibiting liquid water from entering the outlet port. The inner protective tube has an inlet opening for receiving the recirculated gas stream. The anode separation device optionally includes a water separator between the inner protective tube and the outlet port, the water separator being configured to inhibit water splashing back into the inner protective tube. Advantageously, the top wall includes a plurality of concentric ribs to inhibit water from entering the inner protective tube.

[0007] On the other hand, methods and systems for separating liquid water from recirculated gas in a fuel cell system are provided. This method improves water removal efficiency in the fuel cell system by addressing specific problems associated with an anode separation (AKO) device. The AKO device separates water, a byproduct of chemical reactions within the fuel cell stack, from the recirculated gas to allow for the reuse of residual hydrogen.

[0008] On the other hand, the methods and designs for AKO devices in fuel cell systems provide higher efficiency by reducing the gas flow velocity at the critical point, increasing water droplet collection through multiple flow impacts, and providing an effective and comprehensive solution for enhanced water separation.

[0009] On the other hand, the anode separation device provides higher efficiency by reducing the amount of water droplets leaving the outlet pipe and reducing the airflow velocity at the bottom of the protection pipe.

[0010] On the other hand, the anode separation device generates multiple flow impacts to collect water droplets on the surface of the protective tube (non-direct current).

[0011] On the other hand, the anode separation device offers a unique concept characterized by an additional layer of humidity control returning to the fuel cell stack.

[0012] The foregoing description of the invention is merely illustrative and is not intended to be limiting in any way. Other aspects, embodiments, and features will become apparent from the accompanying drawings and the following detailed description, in addition to the illustrative aspects, embodiments, and features described above. Attached Figure Description

[0013] To further understand the nature, objectives, and advantages of this disclosure, reference should be made to the following detailed description, in conjunction with the accompanying drawings, wherein like reference numerals denote like elements, and in the drawings:

[0014] Figure 1 This is a schematic diagram of an existing anode separation device.

[0015] Figure 2 This is a schematic diagram of a fuel cell system including an anode separation unit.

[0016] Figure 3A It is possible Figure 2 A side view of the anode separation device used in a fuel cell system.

[0017] Figure 3B It is possible Figure 2 A top view of the anode separation unit used in a fuel cell system.

[0018] Figure 3C It is possible Figure 2 A vertical cross-sectional view of the anode separation device used in a fuel cell system.

[0019] Figure 4 It is a vertical cross-sectional view of the inner protective tube 60 with chamfered edges.

[0020] Figure 5A This is a vertical cross-sectional view of the anode separation device, in which the exhaust inlet port is modified to redirect the flow of the input exhaust gas.

[0021] Figure 5B This is a horizontal cross-sectional view of the anode separation unit, in which the exhaust inlet port is modified to redirect the flow of the input exhaust gas.

[0022] Figure 6 This is a vertical cross-sectional view of an anode separation device 40 with a modified top wall.

[0023] Figure 7A It is a vertical cross-sectional view of an anode separation device with an inner protective tube, wherein the diameter of at least one section of the inner protective tube is larger than the diameter of the outlet port.

[0024] Figure 7B It is a vertical cross-sectional view of an anode separation device with an inner protective tube, wherein the diameter of at least one section of the inner protective tube is larger than the diameter of the outlet port.

[0025] Figure 7C It is a vertical cross-sectional view of an anode separation device with an inner protective tube, wherein the diameter of at least one section of the inner protective tube is larger than the diameter of the outlet port.

[0026] Figure 8A This is a vertical cross-sectional view of an anode separation device with an inner protective tube assembly having two curved protective covers.

[0027] Figure 8B This is a horizontal cross-sectional view of an anode separation device with an inner protective tube assembly having two curved protective shields.

[0028] Figure 9A This is a vertical cross-sectional view of an anode separation device with an inner protective tube assembly having two centrifuge tubes.

[0029] Figure 9B This is a horizontal cross-sectional view of an anode separation device with an inner protective tube assembly having two centrifuge tubes.

[0030] Figure 10 This is a schematic diagram of a test system used to evaluate an anode separation device.

[0031] Figure 11 Is using Figure 10 The testing system tests the results of various anode separation device designs. Detailed Implementation

[0032] Reference will now be made in detail to the presently preferred embodiments and methods of the invention, which constitute the best mode of practicing the invention as currently known to the inventors. The drawings are not necessarily drawn to scale. However, it should be understood that the disclosed embodiments are merely examples of the invention that may be embodied in various forms and alternative forms. Therefore, the specific details disclosed herein are not to be construed as limiting, but only as representative of any aspect of the invention and / or as teaching those skilled in the art to adopt the invention in various ways.

[0033] It should also be understood that the present invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may vary. Furthermore, the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting in any way.

[0034] It must also be noted that, unless the context clearly indicates otherwise, as used in the specification and appended claims, the singular forms “a / an” and “described” include a plural of indicators. For example, referring to a component in the singular is intended to include multiple components.

[0035] The term "comprising" is synonymous with "including," "having," "containing," or "characterized in." These terms are inclusive and open-ended and do not exclude additional, undescribed elements or method steps.

[0036] The phrase "consisting of" excludes any element, step, or component not specified in the claims. When this phrase appears in a clause of the body of a claim, rather than immediately following the preamble, it only limits the element set forth in that clause; the entire claim does not exclude other elements.

[0037] The phrase “consistent essentially of” limits the scope of the claim to the specified materials or steps, plus those materials or steps that do not substantially affect one or more essential and novel features of the claimed subject matter.

[0038] In contrast to the terms “comprising,” “consisting of,” and “substantially composed of,” the use of one of these three terms herein may include the use of either of the other two terms.

[0039] It should also be understood that the integer range explicitly includes all intermediate integers. For example, the integer range 1 to 10 explicitly includes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Similarly, the range 1 to 100 includes 1, 2, 3, 4, ..., 97, 98, 99, and 100. Similarly, when any range is needed, intermediate values ​​that are the increments of the difference between the upper and lower limits divided by 10 can be considered as alternative upper or lower limits. For example, if the range is 1.1 to 2.1, the following values ​​1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 can be chosen as lower or upper limits.

[0040] When referring to numerical quantities, in the improved version, the term "less than" includes a non-inclusive lower limit, which is 5% of the number indicated after "less than". A non-inclusive lower limit means that the numerical quantity described is greater than the value indicated as the non-inclusive lower limit. For example, in the improved version, "less than 20" includes a non-inclusive lower limit of 1. Therefore, this improved version of "less than 20" includes the range between 1 and 20. In another improved version, the term "less than" includes non-inclusive lower limits, which are ordered in ascending order of priority as 20%, 10%, 5%, 1%, or 0% of the number indicated after "less than".

[0041] The term "one or more" means "at least one," and the term "at least one" means "one or more." The terms "one or more" and "at least one" include "multiple" as a subset.

[0042] The terms “substantially,” “generally,” or “about” are used herein to describe disclosed or claimed embodiments. The term “substantially” may modify values ​​or relative characteristics disclosed or claimed in this disclosure. In such instances, “substantially” may mean that the value or relative characteristic it modifies is within ±0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, or 10% of the value or relative characteristic.

[0043] As illustrated in the accompanying drawings, the same reference numerals may be used herein to refer to the same parameters and components or similar modifications and alternatives thereof. For the purposes of this description, the directional terms “up,” “down,” “right,” “left,” “back,” “front,” “vertical,” “horizontal,” and their derivatives shall be used in connection with this disclosure, such as… Figure 3A , Figure 3C , Figure 4 , Figure 5A , Figure 6 , Figure 7A , Figure 7B , Figure 7C , Figure 8A and Figure 9A The orientation is as described above. This orientation ensures that the liquid water collects at the bottom under gravity. However, it should be understood that various alternative orientations may be employed in this disclosure unless explicitly stated otherwise. It should also be understood that the specific apparatus and processes shown in the drawings and described in the following description are merely exemplary embodiments of the inventive concept defined in the appended claims. Therefore, the specific dimensions and other physical characteristics relating to the embodiments disclosed herein should not be considered limiting unless otherwise expressly stated in the claims. The drawings referenced herein are schematic, and their related views are not necessarily drawn to scale.

[0044] Abbreviations:

[0045] “AKO” means anode separation.

[0046] "OSA" means that it is the same as in other respects.

[0047] "FCS" stands for Fuel Cell System.

[0048] like Figure 1 The existing AKO design 10, as depicted, includes an outer cylinder canister 12 with a small protective tube 14 positioned therein. The protective tube is intended to prevent water droplets from flowing directly into the outlet pipe with the airflow. The AKO design 10 includes: an inlet port 16 that receives exhaust gas from the anode side of the fuel cell system; and a recirculation outlet pipe 18 that recirculates the gas back to the fuel cell stack, where liquid water is removed from the fuel cell stack. This configuration results in a high gas velocity at the inlet port 16. This high velocity can cause dripping water to be blown back into the recirculation outlet pipe 18, thus reducing water separation efficiency. Water is collected at the bottom of the outer cylindrical canister by direct impact on the outer surface of the protective tube and the inner surface of the outer cylindrical canister. However, due to the small size of the protective tube and the high gas velocity at the bottom flow inlet, this can cause dripping.

[0049] refer to Figure 2 A schematic diagram of a fuel cell system, including an anode separation unit, is provided. (Reference) Figure 1 A schematic diagram of a fuel cell system with an anode separation device is provided. The fuel cell system 30 includes a fuel cell stack 32, which includes a plurality of fuel cells 34. Typically, hydrogen is supplied to the anode and oxygen to the cathode. An anode separation device 40 receives exhaust gas from the anode side of the fuel cell stack 32. This exhaust gas may include hydrogen (H2), nitrogen, liquid water, and water vapor. Liquid water can exit from the anode separation device 40 via a drain valve 68.

[0050] refer to Figure 3A , Figure 3B and Figure 3C It provides the option to merge into Figure 1 A schematic diagram of the anode separation device in a fuel cell system. Figure 3A A side view of the anode separation unit is provided, while Figure 3B A top view of the anode separation unit is provided. Figure 3C This is a vertical cross-sectional view of the anode separation device. The anode separation device 40 includes an outer cylindrical tank 42 having sidewalls 44, a top wall 46, and a bottom wall 48. The sidewalls 44 include an air inlet port 50, which is configured to allow air to enter from... Figure 1The anode side of the fuel cell stack 32 receives an input flow 52 (e.g., exhaust gas). A top wall 46 includes an outlet port 54 through which a recirculated gas flow 56 flows. Typically, the recirculated gas flow 56 includes H2, N2, and may include some water vapor. It is desirable that the recirculated gas flow 56 includes a minimal amount of water droplets. An inner protective tube 60 is positioned within the outer cylindrical tank 42 and is in fluid communication with the outlet port 54. The inner protective tube 60 is configured to allow the separated gas flow (i.e., the recirculated gas flow 56) to reach the outlet port while inhibiting (e.g., preventing) liquid water from being carried into the outlet. The inner protective tube defines an inlet opening 62 for receiving the separated gas flow. An outlet port 64 is located at the bottom of the anode separation device 20, at the bottom of the sidewall, or within the bottom wall. In an improved embodiment, an outlet pipe 66, in fluid communication with the outlet port 64, is positioned to collect liquid water separated from the gas flow within the outer cylindrical tank. A drain valve 68 can be used to control the flow of water from the anode separator 40. In an improved embodiment, a water separator 69 is located inside the anode separator 40 between the inner protective tube 60 and the water outlet port 63. Typically, the water separator 69 is a grid (e.g., a stainless steel grid) configured to prevent water splashing back into the inner protective tube 60. Advantageously, the anode separator 40 is modified to reduce (i.e., suppress) the formation of water droplets that may be entrained in the recirculated gas stream 56. In this regard, modifications are made to the top wall 46, the inlet port 50, and the inner protective tube 60 for this purpose.

[0051] It should be understood that the anode separation device 40 is not limited by its construction material, which can be metal (e.g., stainless steel) or plastic (e.g., nylon, polyethylene, Teflon, etc.). The anode separation device 40 can be formed by molding, 3D printing, or any suitable process known in the art. Similarly, the anode separation device 40 is not limited by its spatial dimensions. For example, the walls of the component can have any suitable thickness, typically from 0.1 inches to 0.25 inches.

[0052] On the other hand, the ratio of the distance d1 from the bottom surface of the top wall 46 to the top of the inner surface 70 of the air inlet port 50 (i.e., the closest point from the inner surface 70 to the top wall 46) to the distance d2 from the bottom surface of the top wall 46 to the top surface of the water separator 69 is optimized to suppress water droplets from being entrained in the recirculated gas flow 56. In some improvements, the ratio of d1 to d2 is at least 0.1. In some improvements, the ratio of d1 to d2 is at least 0.07, 0.08, 0.09, 0.1, 0.12, 0.125, 0.13, or 0.14, and at most 0.16, 0.15, 0.14, or 0.13. These values ​​are greater than the prior art design where the ratio of d1 to d2 is 0.054.

[0053] On the other hand, the ratio of the distance d3 from the bottom surface of the top wall 46 to the bottom of the inner surface 70 of the air inlet port 50 (i.e., the farthest point from the inner surface 70 to the top wall 46) to the length d4 of the inner protective tube 60 is optimized to suppress water droplets from being entrained in the recirculated gas flow 56. The length d4 is the extent to which the inner protective tube 60 enters the cylindrical tank 42. In some improvements, the ratio of d3 to d4 is at least 0.5. In some improvements, the ratio of d3 to d4 is at least 0.48, 0.49, 0.5, 0.51, or 0.52, and at most 0.8, 0.7, 0.6, 0.59, 0.58, 0.56, or 0.54. These values ​​are greater than the prior art design where the ratio of d3 to d4 is 0.445.

[0054] refer to Figure 4 A cross-sectional view of an inner protective tube 60 with chamfered edges is provided. As depicted, the edge 76 of the inner protective tube 60 is chamfered (e.g., angled). The chamfered edge can be on the inner or outer surface of the inner protective tube 60. In an improved embodiment, the chamfered edge extends 0.25 inches to 1 inch from the bottom of the inner protective tube 60. As described below, this configuration reduces the formation of water droplets and thus reduces the entrainment of such water droplets in the recirculated gas stream 56.

[0055] refer to Figure 5A and Figure 5B A cross-sectional view of the anode separation device 40 is provided, wherein the inlet port 50 is modified to redirect the flow of the input flow 52. As depicted, the inner surface 70 is configured to guide the airflow (of the inlet flow 52) downward and laterally away from the inner protective tube 60. In this respect, protrusions or contours 72 may be formed on the inner surface 70 to guide the flow in this manner.

[0056] refer to Figure 6 A cross-sectional view of an anode separation device 40 with a modified top wall is provided. The top wall 46 of the cylindrical tank 42 includes a plurality of concentric ribs 74, 76 to prevent water from entering the inner protective tube. In an improved embodiment, the top wall 46 includes two concentric ribs.

[0057] refer to Figure 7A , Figure 7B and Figure 7CA cross-sectional view of an anode separation device 40 with an inner protective tube is provided, the inner protective tube having at least one section with a diameter larger than that of the outlet port 54. In an improved embodiment, the inner protective tube 60 has a section with a diameter at least twice that of the outlet port. In another improved embodiment, these designs use a larger protective tube with a diverging cone shape at the bottom, instead of a small, straight protective tube. This design provides two significant benefits: First, the increased gas velocity outside the protective tube enhances the direct impact of water droplets on the outer surface of the protective tube, thereby reducing the number of water droplets inside the device. Second, the reduced gas velocity at the bottom of the protective tube minimizes the possibility of water droplets at the bottom edge of the protective tube being blown into the outlet pipe.

[0058] refer to Figure 7A At least a portion of the inner protective tube 60 flares outward in the direction of the inlet opening. Therefore, an inverted inner cone 80 is incorporated within the inner protective tube 60. The inlet 82 of the inner cone 80 is smaller than its outlet 84, thereby effectively collecting water droplets and films before they enter the inlet of the inner cone 80.

[0059] refer to Figure 7B The inner protective tube 60 comprises a two-stage protective tube. As depicted, the inner protective tube 60 includes a first section 90 and a second section 92, wherein during operation of the anode separation unit 40, the first section 90 is downstream of the second section 92. The downstream section 90 has a larger diameter than the second section 92, thereby reducing the gas velocity as gas enters the two-stage protective tube.

[0060] refer to Figure 7C The inner protective tube 60 also includes a two-section protective tube. The top portion 100 is shaped as a diverging cone, and the bottom portion 102 is shaped as a straight tube with a significantly larger diameter. During operation of the anode separation unit 40, the top portion 100 is downstream of the bottom portion 102. These design concepts collectively reduce the velocity of the gas after entering the protective tube and prevent water droplets from being blown upwards into the protective tube.

[0061] In another aspect, an anode separation device is provided for separating liquid water from a recirculated gas stream in a fuel cell system. The anode separation device includes an outer cylindrical canister having a sidewall with an inlet port. The anode separation device also includes a top wall having an outlet port and an inner surface, and a bottom wall having a water outlet port. The inlet port is configured to receive an input stream from the anode side of the fuel cell system. The anode separation device also includes an inner protective tube assembly positioned within the outer cylindrical canister in fluid communication with the outlet port. The inner protective tube assembly includes a first inner protective tube component and a second inner protective tube component, configured to cooperate to allow the separated gas stream to reach the outlet port while preventing liquid water from being carried into the outlet port. Figure 8A , Figure 8B , Figure 9A and Figure 9B It describes a certain variation in this aspect.

[0062] refer to Figure 8A and Figure 8B A cross-sectional view of an anode separation device with an inner protective tube is provided, which has two curved protective shields instead of a small, straight, circular protective tube. The anode separation device 40 includes an inner protective tube assembly 110, which includes a first protective shield 112 and a second protective shield 114. The first protective shield 112 is larger than the second protective shield 114. Furthermore, the first protective shield 112 is closer to the inlet port 50, with its outer side facing the inlet port 50. In other words, the larger front protective shield 112 is designed and mounted such that its opening section faces the device inlet port 50. The smaller rear protective shield 114 is designed and mounted such that its opening section faces the device inlet port 50, opposite the opening section of the front protective shield 112. This design provides three significant benefits: large water droplets are collected on the outer surface of the front protective shield due to their large momentum; medium-sized water droplets are collected on the rear inner surface of the outer tube of the device; and small water droplets are collected on the outer surface of the rear protective shield.

[0063] refer to Figure 9A and Figure 9BA cross-sectional view of an anode separation device with two concentrically mounted circular protective tubes is shown. The anode separation device 40 includes an inner tube 120 and an outer tube 122. The inner tube 120 has a smaller diameter than the outer tube 122. Furthermore, the smaller inner tube 120 is positioned inside the larger outer tube 122. The outer tube 122 is characterized by having a first row of perforations 124 on its rear side opposite to the air inlet port 50, while the inner tube 120 has a second row of perforations 128 on its front side facing the air inlet port 50. The bottom side 130 of the inner tube 120 is completely sealed. A drain hole 132 is designed on the rear side of the bottom seal 134 of the outer tube 122. This design provides four benefits: large water droplets are collected on the outer surface of the outer protective tube due to their large momentum; medium water droplets are collected on the rear inner surface of the outer tube of the device; small water droplets are collected on the outer surface of the inner protective tube; and very small water droplets are collected on the inner surface of the outer protective tube.

[0064] It should be understood that two or more of the anode separation devices in Figures 3 to 9 can be combined into a single anode separation device.

[0065] The following examples illustrate various embodiments of the invention. Those skilled in the art will recognize many variations within the spirit and scope of the claims.

[0066] Evaluate the efficiency of the anode separator in collecting water and preventing water droplets from leaving with the gas. Compare several AKO designs (C1 to C4) with a baseline design to assess efficiency.

[0067] The design specifications are as follows:

[0068] C1: Adjust the position of the intake port relative to the length of the inner protective tube. Figure 3C ).

[0069] C2: Chamfered edge on the inner protective tube ( Figure 4 ).

[0070] C3: Guides the inlet gas flow away from the inner protective tube. Figure 5A and Figure 5B ).

[0071] C4: Includes ribs on the top wall of the outer cylinder canister. Figure 6 ).

[0072] Features include: reduced airflow velocity, multiple flow impacts for water collection, and unique characteristic variations for controlling humidity re-entry into the fuel cell stack. Designs C1 through C4 are injection moldable compatible with baseline designs. The tests provide an understanding of the deviation between the changing airflow direction / droplets and the following main airflow direction.

[0073] Figure 10A schematic diagram of a test system for evaluating the anode separation design described above is provided. Figure 11 Test results were provided. Based on the liquid Liq from the outlet pipe (i.e., the tank). E And liquid Liq from the recirculated gas stream (i.e., the cap) R The efficiency was determined by the data collection. The results are also summarized in Table 1.

[0074] Table 1. Efficiency Results

[0075]

[0076] from Figure 11 As observed in Table 1, efficiency gradually increases as AKO design features are combined. The combination of all features from C1 to C4 provides the maximum efficiency.

[0077] While exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the terms used in this specification are descriptive rather than restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the invention. Furthermore, features of various embodiments can be combined to form other embodiments of the invention.

[0078] According to the present invention, an apparatus for separating liquid water from a recirculated gas stream in a fuel cell system is provided, the apparatus comprising: an outer cylindrical can having: a sidewall having an inlet port; a top wall including an outlet port; and a bottom wall having an outlet port attached to either the sidewall or the bottom wall, the inlet port including an inner surface and configured to receive an input stream from the anode side of the fuel cell system; an inner protective tube positioned within the outer cylindrical can in fluid communication with the outlet port, the inner protective tube being configured to allow separated gas streams to reach the outlet port while preventing liquid water from being carried into the outlet port, the inner protective tube defining an inlet opening for receiving the separated gas streams, wherein a first distance from the top of the inner surface of the inlet port to the length of the inner protective tube is optimized to suppress water droplets being entrained in the recirculated gas stream; and a water separator between the inner protective tube and the outlet port, the water separator being configured to suppress water splashing back into the inner protective tube.

[0079] According to an embodiment, the ratio of the distance from the bottom surface of the top wall to the top of the inner surface of the air inlet port to the distance from the bottom surface of the top wall to the top surface of the water separator is at least 0.1.

[0080] According to an embodiment, the ratio of the distance from the bottom surface of the top wall to the bottom of the inner surface of the air intake port to the length of the inner protective tube is at least 0.5.

[0081] According to an embodiment, the outlet pipe is in fluid communication with the outlet port, which is positioned to collect liquid water separated from the gas flow inside the outer cylindrical tank.

[0082] According to an embodiment, the inner protective tube includes a chamfered edge.

[0083] According to an embodiment, the air intake port has a shape configured to guide airflow downwards and laterally away from the inner protective tube.

[0084] According to an embodiment, the top wall includes a plurality of concentric ribs to prevent water from entering the inner protective tube.

[0085] According to an embodiment, at least a portion of the inner protective tube is flared outward in the direction toward the inlet opening.

[0086] According to an embodiment, the inner protective tube includes a section with a diameter larger than that of the air outlet port.

[0087] According to an embodiment, the inner protective tube has a section with a diameter at least twice the diameter of the air outlet port.

[0088] According to an embodiment, the inner protective tube has an inverted cone positioned therein.

[0089] According to an embodiment, a fuel cell stack includes means in fluid communication with the anode side of the fuel cell stack as described in the previous embodiment.

[0090] According to the present invention, an apparatus for separating liquid water from a recirculated gas stream in a fuel cell system is provided, the apparatus comprising: an outer cylindrical can having: a sidewall having an inlet port; a top wall including an outlet port; and a bottom wall having an outlet port attached to either the sidewall or the bottom wall, the inlet port including an inner surface and configured to receive an input stream from the anode side of the fuel cell system; an inner protective tube assembly positioned within the outer cylindrical can in fluid communication with the outlet port, the inner protective tube assembly including a first inner protective tube component and a second inner protective tube component configured to cooperate to allow separated gas streams to reach the outlet port while preventing liquid water from being carried into the outlet port; and a water separator between the inner protective tube assembly and the outlet port, the water separator being configured to suppress water splashing back into the inner protective tube assembly.

[0091] According to an embodiment, the inner protective tube assembly includes a first protective cover and a second protective cover, wherein the first protective cover is larger than the second protective cover.

[0092] According to an embodiment, the first protective cover is closer to the air intake port than the second protective cover, wherein the outer side of the first protective cover faces the air intake port and the opening section of the second protective cover, and is opposite to the opening section of the first protective cover.

[0093] According to an embodiment, the inner protective tube assembly includes an inner tube and an outer tube, wherein the inner tube has a smaller diameter than the outer tube.

[0094] According to an embodiment, the outer tube includes a first row of perforations on its rear side opposite to the air intake port, while the inner tube has a second row of perforations on its front side facing the air intake port.

[0095] According to an embodiment, the bottom side of the inner tube is completely sealed.

[0096] According to an embodiment, the bottom side of the outer tube includes a drain hole.

[0097] According to the present invention, an apparatus for separating liquid water from a recirculated gas stream in a fuel cell system is provided, the apparatus comprising: an outer cylindrical can having: a sidewall having an inlet port; a top wall including an outlet port; and a bottom wall having an outlet port attached to the sidewall or the bottom wall, the inlet port including an inner surface and configured to receive an input stream from the anode side of the fuel cell system; an inner protective tube positioned within the outer cylindrical can in fluid communication with the outlet port, the inner protective tube being configured to allow separated gas streams to reach the outlet port while preventing liquid water from being carried into the outlet port, the inner protective tube defining an inlet opening for receiving the separated gas streams, wherein a plurality of concentric ribs on the top wall inhibit water from entering the inner protective tube; and a water separator between the inner protective tube and the outlet port, the water separator being configured to inhibit water splashing back into the inner protective tube.

Claims

1. An apparatus for separating liquid water from a recirculated gas stream in a fuel cell system, comprising: an outer cylindrical can having: a sidewall having a gas inlet port; a top wall including a gas outlet port; and a bottom wall, a water outlet port attached to the sidewall or the bottom wall, the gas inlet port including an inner surface and configured to receive an input stream from an anode side of the fuel cell system; an inner guard tube positioned within the outer cylindrical can in fluid communication with the gas outlet port, the inner guard tube configured to allow a separated gas stream to reach the gas outlet port while preventing liquid water from being carried into the gas outlet port, the inner guard tube defining an inlet opening for receiving the separated gas stream, wherein a ratio of a first distance from a top of the inner surface of the gas inlet port to a length of the inner guard tube is optimized to suppress water droplets from being entrained in the recirculated gas stream; and a water separator between the inner guard tube and the water outlet port, the water separator configured to suppress water from splashing back into the inner guard tube.

2. The apparatus of claim 1, wherein a ratio of a distance from a bottom surface of the top wall to the top of the inner surface of the gas inlet port to a distance from the bottom surface of the top wall to a top surface of the water separator is at least 0.

1.

3. The apparatus of claim 1, wherein a ratio of a distance from a bottom surface of the top wall to a bottom of the inner surface of the gas inlet port to the length of the inner guard tube is at least 0.

5.

4. The apparatus of claim 1, wherein a water outlet tube is in fluid communication with the water outlet port, the water outlet port positioned to collect the liquid water separated from a gas stream within the outer cylindrical can.

5. The apparatus of claim 1, wherein the inner guard tube includes a chamfered edge.

6. The apparatus of claim 5, wherein the gas inlet port has a shape configured to direct a gas stream downward and laterally away from the inner guard tube.

7. The apparatus of claim 5, wherein the top wall includes a plurality of concentric ribs to suppress water from entering the inner guard tube.

8. The apparatus of claim 1, wherein at least a portion of the inner guard tube flares outward in a direction toward the inlet opening.

9. The apparatus of claim 1, wherein the inner guard tube includes a section having a diameter greater than a diameter of the gas outlet port.

10. The apparatus of claim 1, wherein the inner guard tube has a section having a diameter at least twice as great as the diameter of the gas outlet port.

11. The apparatus of claim 1, wherein the inner guard tube has an inverted cone positioned therein.

12. A fuel cell stack comprising the apparatus of claim 1 in fluid communication with an anode side of the fuel cell stack.

13. An apparatus for separating liquid water from a recirculated gas stream in a fuel cell system, comprising: an outer cylindrical can having: a sidewall having a gas inlet port; a top wall including a gas outlet port; and a bottom wall, the water outlet port attached to the side wall or the bottom wall, the gas inlet port comprising an inner surface and configured to receive an input flow from an anode side of the fuel cell system; an inner guard tube assembly positioned within the outer cylindrical can in fluid communication with the gas outlet port, the inner guard tube assembly comprising a first inner guard tube component and a second inner guard tube component, the first and second inner guard components configured to cooperate to allow a separate gas flow to the gas outlet port while preventing liquid water from being carried into the gas outlet port; and a water separator between the inner guard tube assembly and the water outlet port, the water separator configured to inhibit water from splashing back into the inner guard tube assembly.

14. The apparatus of claim 13, wherein the inner guard tube assembly comprises a first guard and a second guard, the first guard being larger than the second guard.

15. The apparatus of claim 14, wherein the first guard is closer to the gas inlet port than the second guard, wherein an outer side of the first guard faces the gas inlet port and an open section of the second guard, opposite the open section of the first guard.

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