Tail gas catalytic treatment device, processing method thereof and fuel cell hydrogen elimination system

Abstract

The invention discloses a tail gas catalytic treatment device, a processing method thereof and a fuel cell dehydrogenation system, and relates to the technical field of tail gas treatment. The tail gas catalytic treatment device comprises a catalytic module; the catalytic module comprises a plurality of catalytic honeycomb carrier layers sequentially arranged in the preset exhaust direction and catalytic particle layers located between every two adjacent catalytic honeycomb carrier layers. The catalytic module is of a sandwich type segmented structure formed by a catalytic honeycomb carrier layer and a catalytic particle layer, tail gas alternately flows through the catalytic honeycomb carrier layer and the catalytic particle layer, the advantages of the two catalytic structures can be fully played, and high mass transfer efficiency and high catalytic efficiency are achieved. According to the multi-layer catalytic layer, when the concentration of the to-be-treated component suddenly rises, the reaction load is distributed to each catalytic layer, so that the load amplification of a single catalytic layer can be reduced, each catalytic layer can operate in a safe operation interval, and the conversion rate of the to-be-treated component in the tail gas is ensured.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas treatment technology, and in particular to an exhaust gas catalytic treatment device and its processing method, and a fuel cell hydrogen removal system. Background Technology

[0002] Fuel cells are widely used in vehicle power systems due to their high efficiency and environmental friendliness. Among various types of fuel cells, hydrogen fuel cells use hydrogen and oxygen in an electrochemical reaction to generate electricity and water, and the exhaust gas produced by the reaction contains hydrogen. Because the explosive limits of hydrogen are wide (4% to 46%), fuel cell vehicles must reduce the hydrogen concentration in their exhaust gas to a safe range to ensure safety; in most other applications, hydrogen fuel cells also need to ensure that the hydrogen concentration in the exhaust gas is well below 4% to avoid combustion or explosion.

[0003] Currently, one technology for reducing hydrogen concentration in exhaust gases is to use catalytic reactions or absorption techniques to reduce or eliminate hydrogen in the emissions, thereby effectively lowering the hydrogen concentration in the exhaust gases. Specifically, exhaust hydrogen is mixed with air in a certain proportion and then sent to a catalytic combustion chamber for a catalytic reaction to eliminate hydrogen in the exhaust gases. However, this system lacks a rapid response control strategy for sudden increases in hydrogen concentration, carries the risk of incomplete reaction, affects conversion rate, and has a complex structure.

[0004] Therefore, ensuring the conversion rate of the components to be treated in the exhaust gas is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an exhaust gas catalytic treatment device and its processing method, and a fuel cell hydrogen removal system, which can ensure the conversion rate of the components to be treated in the exhaust gas.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of the present invention provides an exhaust gas catalytic treatment device, including a catalytic module; the catalytic module includes a plurality of catalytic honeycomb carrier layers arranged sequentially along a preset exhaust direction, and catalytic particle layers respectively located between every two adjacent catalytic honeycomb carrier layers.

[0008] In one exemplary embodiment, the three catalytic honeycomb carrier layers are a first honeycomb layer, a second honeycomb layer, and a third honeycomb layer arranged sequentially along the exhaust direction; the two catalytic particle layers are a first particle layer and a second particle layer arranged sequentially along the exhaust direction, with the two sides of the first particle layer respectively attached to the first honeycomb layer and the second honeycomb layer, and the two sides of the second particle layer respectively attached to the second honeycomb layer and the third honeycomb layer.

[0009] In one exemplary embodiment, the system further includes a main housing, a first housing, and a second housing; the catalytic module is built into the main housing; the first housing and the second housing are detachably connected to both sides of the main housing and are respectively sealed to both sides of the catalytic module; along the exhaust direction, the first housing, the main housing, and the second housing are arranged in sequence and connected, and the gas enters the catalytic module through the inlet on the first housing and is then discharged through the outlet on the second housing.

[0010] In one exemplary embodiment, the first housing and the second housing are respectively connected to the main housing by clamps, and the first housing and the second housing are respectively sealed to the catalytic module by gaskets.

[0011] In one exemplary embodiment, the catalytic honeycomb carrier layer includes a honeycomb carrier, the interior of which is filled with an alumina coating and then loaded with a palladium-platinum component.

[0012] In one exemplary embodiment, the catalytic honeycomb carrier layer has a microchannel structure and is made of cordierite ceramic substrate, wherein the number of channels in the catalytic honeycomb carrier layer ranges from 200 to 600 mesh; in the palladium-platinum composition of the catalytic honeycomb carrier layer, the palladium content is 2-3 g / L carrier and the platinum content is 0.5-1 g / L carrier.

[0013] In one exemplary embodiment, the particles of the catalytic particle layer are made of spherical alumina substrate with a palladium-platinum component loaded on the surface.

[0014] In one exemplary embodiment, the spherical alumina substrate has a particle size of 2-4 mm, a specific surface area of ​​≥200 m² / g, a bulk density of 1.2-1.4 g / cm³, a surface-loaded palladium content of 5-8 wt%, a platinum content of 1-2 wt%, and a filling rate of 1 t-400 g.

[0015] A second aspect of the present invention provides a processing method for an exhaust gas catalytic treatment device, applicable to the exhaust gas catalytic treatment device as described above. The processing method includes a step of preparing the catalytic honeycomb carrier layer. The step of preparing the catalytic honeycomb carrier layer includes: first impregnating the honeycomb carrier in a nitrate solution containing palladium-platinum precursors, draining it, and then calcining it, thereby forming a uniformly distributed catalytic active layer on the honeycomb carrier.

[0016] In one exemplary embodiment, during the subsequent calcination after draining, the calcination temperature is T, where 448℃≤T≤452℃, and the calcination time is t hours, where 2.8≤t≤3.2.

[0017] A third aspect of the present invention provides a processing method for an exhaust gas catalytic treatment device, applicable to the exhaust gas catalytic treatment device described above. The processing method includes a step of preparing the catalytic particle layer. The step of preparing the catalytic particle layer includes: first impregnating raw material particles with a solution of palladium chloride and chloroplatinic acid, then pretreating them in air at a first temperature, wherein the raw material particles are spherical alumina substrates; then reducing them in a hydrogen atmosphere at a second temperature to obtain finished particles with metallic active components; and placing the finished particles into the gaps between adjacent catalytic honeycomb carrier layers, thereby achieving close contact and connection with the corresponding catalytic honeycomb carrier layers.

[0018] In one exemplary embodiment, 298℃≤first temperature≤302℃, and 398℃≤second temperature≤402℃.

[0019] In one exemplary embodiment, the finished particles are placed into the gaps between adjacent catalytic honeycomb carrier layers by gravity filling or vibration compaction.

[0020] A third aspect of the present invention provides a hydrogen removal system for a fuel cell, comprising the above-mentioned tail gas catalytic treatment device; a fuel cell stack, wherein the anode outlet is connected to a first branch, the cathode outlet is connected to a second branch, the outlet of the second branch is connected to the inlet of a first air exhaust branch and the inlet of a second air exhaust branch; a water separator, wherein the inlet is connected to the outlet of the first branch, the outlet of the first air exhaust branch and the first outlet of the water separator are both connected to the inlet of the tail gas catalytic treatment device, and the outlet of the tail gas catalytic treatment device is connected to the second air exhaust branch through a third branch.

[0021] In one exemplary embodiment, a first control unit is connected to the first branch or the first air exhaust branch to control the gas flow rate of the first branch or the first air exhaust branch, so that the gas flow rate ratio provided by the outlet of the first air exhaust branch and the first outlet to the exhaust gas catalytic treatment device is within a preset range.

[0022] In one exemplary embodiment, the ratio of hydrogen exhaust gas received by the exhaust gas catalytic treatment device from the water separator to air exhaust gas received from the first air exhaust branch is 1:8 to 1:12.

[0023] In one exemplary embodiment, the third branch and the second air exhaust branch are connected via a vortex mixer.

[0024] In one exemplary embodiment, the second outlet of the water separator is connected to the hydrogen inlet of the fuel cell stack via a recirculation branch.

[0025] In one exemplary embodiment, the flow rate of gas discharged from the water separator through the second outlet is greater than the flow rate of gas discharged through the first outlet.

[0026] In one exemplary embodiment, an exhaust valve is further provided between the first outlet of the water separator and the inlet of the exhaust gas catalytic treatment device; the exhaust valve is communicatively connected to a controller, which controls the exhaust valve to open intermittently.

[0027] The exhaust gas catalytic treatment device provided by the present invention includes a catalytic module; the catalytic module includes multiple catalytic honeycomb carrier layers arranged sequentially along a preset exhaust direction, and catalytic particle layers located between each pair of adjacent catalytic honeycomb carrier layers.

[0028] The above-mentioned exhaust gas catalytic treatment device has a sandwich-style segmented structure consisting of a catalytic honeycomb carrier layer and a catalytic particle layer. The exhaust gas flows alternately through the catalytic honeycomb carrier layer and the catalytic particle layer. Most of the gas can be quickly treated in the catalytic honeycomb carrier layer, while the catalytic particle layer can enhance mass transfer and deeply purify the incoming exhaust gas. This fully leverages the advantages of the two catalytic structures to achieve high mass transfer efficiency and high catalytic efficiency.

[0029] In addition, by using multi-layered catalytic layers, when the concentration of the component to be treated increases sharply, the reaction load is distributed to each catalytic layer, which can reduce the load increase of a single catalytic layer. This allows each catalytic layer to operate within a safe operating range, preventing it from entering an overload protection state due to a sudden increase in load, thus avoiding a sharp drop in conversion rate. This also avoids response delay, reduces the risk of incomplete reaction, and ensures the conversion rate of the component to be treated in the exhaust gas. Furthermore, the layered arrangement of each catalytic layer results in a simple structure that is easy to process. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 A schematic diagram of the exhaust gas catalytic treatment device according to a specific embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of a fuel cell hydrogen removal system according to a specific embodiment of the present invention.

[0033] Figure label:

[0034] First housing 1, first clamp 11, first sealing gasket 12;

[0035] Catalytic module 2, catalytic honeycomb carrier layer 21, first honeycomb layer 211, second honeycomb layer 212, third honeycomb layer 213, catalytic particle layer 22, first particle layer 221, second particle layer 222;

[0036] Second housing 3, second clamp 31, second sealing gasket 32;

[0037] Main shell 4;

[0038] Fuel cell stack 5, first branch 51, second branch 52, first air exhaust branch 521, second air exhaust branch 522, hydrogen inlet 53, air inlet 54;

[0039] Water separator 6, recirculation branch 61;

[0040] Exhaust valve 7;

[0041] Exhaust gas catalytic treatment device 8, third branch 81. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The core of this invention is to provide a tail gas catalytic treatment device and its processing method, and a fuel cell hydrogen removal system, which can ensure the conversion rate of the components to be treated in the tail gas.

[0044] In a specific embodiment one of the exhaust gas catalytic treatment devices provided by the present invention, such as Figure 1 As shown, it includes catalytic module 2.

[0045] The catalytic module 2 includes multiple catalytic layers arranged sequentially along a preset exhaust direction. Some of the catalytic layers are multiple catalytic honeycomb carrier layers 21 arranged sequentially along the preset exhaust direction, and some of the catalytic layers are catalytic particle layers 22 located between every two adjacent catalytic honeycomb carrier layers 21.

[0046] The catalytic honeycomb carrier layer 21 and the catalytic particle layer 22 are each provided with active components. The types of active components in the catalytic honeycomb carrier layer 21 and the catalytic particle layer 22 can be the same or different.

[0047] Specifically, the catalytic honeycomb support layer 21 has a monolithic continuous honeycomb structure with internal microchannels. The pore structure is regular and interconnected, specifically parallel channels. The active component can be uniformly loaded on the inner wall of the channels in the form of a nano-coating. The catalytic honeycomb support layer 21 can have good contact with the gas, and the catalytic efficiency is usually high.

[0048] Specifically, the catalytic particle layer 22 comprises dispersed spherical or cylindrical particles. The particle packing creates voids, increasing the reaction surface area, allowing active components to be impregnated on the inner and outer surfaces of individual particles. The turbulence created by the particle packing in the catalytic particle layer 22 can enhance mass transfer in certain reactions.

[0049] In this embodiment, the component to be eliminated from the exhaust gas is hydrogen. In this case, the exhaust gas catalytic treatment device is a catalytic combustion hydrogen removal device, which can be specifically applied to hydrogen fuel cells. In other embodiments, depending on actual needs, it can also be used to eliminate other components, and appropriate catalysts can be provided accordingly.

[0050] The above-mentioned tail gas catalytic treatment device uses a sandwich-style segmented structure consisting of a catalytic honeycomb carrier layer 21 and a catalytic particle layer 22. The tail gas flows alternately through the catalytic honeycomb carrier layer 21 and the catalytic particle layer 22, which can give full play to the advantages of the two catalytic structures, achieve high mass transfer efficiency and high catalytic efficiency, provide a large specific surface area and high reactivity, and can efficiently convert hydrogen into water vapor in a short reaction time, thereby achieving the complete elimination of hydrogen in the tail gas and enhancing the safety and stability of the system operation.

[0051] In addition, by using multi-layered catalytic layers, when the hydrogen concentration rises sharply, the reaction load is distributed to each catalytic layer, which can reduce the load increase of a single catalytic layer. This allows each catalytic layer to operate within a safe operating range and prevents it from entering an overload protection state due to a sudden increase in load, which would cause a sharp drop in conversion rate. This avoids response delay, reduces the risk of incomplete reaction, and ensures the conversion rate of the components to be treated in the exhaust gas. Furthermore, the catalytic layers are arranged in layers, resulting in a simple structure that is easy to process.

[0052] Furthermore, such as Figure 1 As shown, the catalyst layer consists of 5 layers, of which the catalyst honeycomb carrier layer 21 has three layers and the catalyst particle layer 22 has two layers.

[0053] Specifically, the three-layer catalytic honeycomb carrier layer 21 consists of a first honeycomb layer 211, a second honeycomb layer 212, and a third honeycomb layer 213 arranged sequentially along the exhaust direction. The two-layer catalytic particle layer 22 consists of a first particle layer 221 and a second particle layer 222 arranged sequentially along the exhaust direction. The two sides of the first particle layer 221 are respectively attached to the first honeycomb layer 211 and the second honeycomb layer 212, and the two sides of the second particle layer 222 are respectively attached to the second honeycomb layer 212 and the third honeycomb layer 213.

[0054] At this point, the first honeycomb layer 211 is positioned at the beginning of the catalytic module 2, serving as a preliminary preheating and reaction carrier; the first particle layer 221 fills the space between the first honeycomb layer 211 and the second honeycomb layer 212, and is connected to both the first honeycomb layer 211 and the second honeycomb layer 212 by compression, thereby enhancing mass and heat transfer and reaction activity; the second honeycomb layer 212 is positioned downstream of the first particle layer 221, in close contact with the first particle layer 221, thereby enhancing the intermediate reaction; the second particle layer 222 fills the space between the second honeycomb layer 212 and the third honeycomb layer 213, and is fixedly connected to the second honeycomb layer 212 and the third honeycomb layer 213, thereby further improving the conversion rate; the third honeycomb layer 213 is positioned at the end of the catalytic module 2, connected to the second particle layer 222, and serves as a refining agent.

[0055] High-efficiency hydrogen oxidation can be achieved through the multi-layer catalytic bed in catalytic module 2. In a practical operation, under the condition that the integral of inlet hydrogen gas is ≤3%, the hydrogen removal rate is >93%, the pressure loss is ≤1.5kPa, the start-up time is 5s, the steady-state reaction temperature is controlled within the range of 80-200℃, and the thermal response time is ≤30s.

[0056] Of course, in other embodiments, the number of catalyst layers may also be different, such as 7 layers.

[0057] Furthermore, the exhaust gas catalytic treatment device 8 also includes a main housing 4, a first housing 1, and a second housing 3.

[0058] The main housing 4 is made of 304 stainless steel with a wall thickness of 2mm. The inner surface is polished to reduce flow resistance. The outer diameter of the main housing 4 is φ82mm, the total length is 14cm, and the weight is ≤2kg.

[0059] The catalytic module 2 is built into the main housing 4. Optionally, the catalytic honeycomb carrier layer 21 is embedded in the main housing 4 and connected to adjacent components to ensure uniform gas flow.

[0060] The first housing 1 and the second housing 3 are detachably connected to both sides of the main housing 4, and are respectively sealed to both sides of the catalytic module 2. Along the exhaust direction, the first housing 1, the main housing 4, and the second housing 3 are arranged in sequence and connected. The gas enters the catalytic module 2 through the inlet on the first housing 1, and then exits through the outlet on the second housing 3.

[0061] In some embodiments, the first housing 1 and the second housing 3 are respectively connected to the main housing 4 by clamps, and the first housing 1 and the second housing 3 are respectively sealed to the catalyst module 2 by sealing gaskets.

[0062] Specifically, the first housing 1 is located at the first end of the main housing 4 and is connected to the upstream gas branch through a pipe interface, serving to introduce the mixed gas into the catalytic module 2. The first clamp 11 is fixedly installed on the first housing 1, and the first clamp 11 is fixedly connected to the main housing 4 by bolts, serving to quickly fix and seal the gas. The first sealing gasket 12 is located between the first clamp 11 and the first honeycomb layer 211, and is tightly fitted to both of them, serving to prevent gas leakage.

[0063] Specifically, the second housing 3 is located downstream of the main housing 4 and is connected to the downstream branch via a pipe interface, serving to discharge the gas treated by the catalytic module 2. A second clamp 31 is installed on the second housing 3, and the second clamp 31 is bolted to the second end of the main housing 4 for quick disassembly. A second sealing gasket 32 ​​is located between the third honeycomb layer 213 and the second clamp 31, and is tightly fitted to both, providing a seal between the catalytic module 2 and the second housing 3.

[0064] Optionally, the clamp is made of 316L stainless steel with a passivated surface, and is connected to the main housing 4 via bolts for quick assembly and disassembly. The bolts can be M8 bolts. The inner surface of the clamp features a trapezoidal toothed structure, combined with an O-ring design, to form a reliable mechanical locking and seal with the main housing 4. In other embodiments, the clamp can be connected to the main housing 4 using a magnetic quick-release structure as an alternative to bolt connections.

[0065] Optionally, the sealing gasket is made of high-temperature resistant fluororubber material with an operating temperature of -40℃ to +250℃. The gasket is 2mm thick and has a Shore A hardness of 80, exhibiting excellent heat resistance and chemical stability. It is fitted and connected to the clamp on the same side of the catalytic module 2 and the catalytic module 2, ensuring the sealing performance of the exhaust gas catalytic treatment device 8 under high-temperature catalytic reaction conditions. In other embodiments, the sealing gasket can also be replaced with a metal corrugated gasket to suit even higher temperature environments.

[0066] In this embodiment, the components of the exhaust gas catalytic treatment device 8 are connected by sequential assembly and mechanical fixing to form a sealed reaction channel system, which has the advantages of compact structure, small size and easy maintenance.

[0067] Furthermore, the catalyst in the catalytic honeycomb support layer 21 includes palladium-platinum. Specifically, the catalytic honeycomb support layer 21 includes a honeycomb support, the interior of which is filled with an alumina coating and then loaded with the palladium-platinum component. The alumina coating provides a nanomesh, which can physically isolate the palladium-platinum particles at various locations, allowing each palladium-platinum particle to participate in the reaction, improving the utilization rate of palladium-platinum, and also improving the thermal shock resistance and mechanical stability of the catalytic honeycomb support layer 21.

[0068] Optionally, the catalytic honeycomb support layer 21 has a microchannel structure, is made of cordierite ceramic substrate, has an outer diameter of φ78mm, a length of 20mm, a channel count of 400 mesh, a wall thickness of 0.15mm, a filling rate of 1m³-300g, and a weight of approximately 150g for a single catalytic honeycomb support layer 21. In other embodiments, the channel count of the catalytic honeycomb support layer 21 can be adjusted to other numbers between 200-600 mesh to accommodate different gas flow rates.

[0069] In addition, a γ-Al₂O₃ coating is disposed inside the catalytic honeycomb support layer 21 as a support, and then coated with palladium-platinum catalytic active components. Optionally, the palladium content is 2-3 g / L of the support, and the platinum content is 0.5-1 g / L of the support. Of course, in other embodiments, the catalyst components can be replaced with a palladium-rhodium alloy to achieve cost optimization.

[0070] In some embodiments, the processing method of the exhaust gas catalytic treatment device includes the preparation step of the catalytic honeycomb carrier layer 21. The catalytic coating of the catalytic honeycomb carrier layer 21 is prepared by an impregnation-calcination process, which can make the active components highly dispersed and the coating bonding strength high.

[0071] Specifically, the preparation steps of the catalytic honeycomb support layer 21 include: first, impregnating the honeycomb support in a nitrate solution containing palladium-platinum precursors, draining, and then calcining to form a uniformly distributed catalytic active layer on the honeycomb support. For example, first impregnating in a nitrate solution containing palladium-platinum precursors for 5-10 minutes, draining, and then calcining at T = 450℃ (or other values ​​within the range of 448℃≤T≤452℃) for t = 3 hours (or other values ​​within the range of 2.8≤t≤3.2) to form a uniformly distributed catalytic active layer with a coating thickness of approximately 20-30 μm.

[0072] Furthermore, the catalyst in the catalytic particle layer 22 includes palladium and platinum. Specifically, the particles in the catalytic particle layer 22 are made of spherical alumina substrate, with palladium and platinum components loaded on the surface. The spherical shape is isotropic, ensuring equal mass transfer resistance regardless of the gas contact direction. The stacking also forms regular voids, achieving uniform gas flow. Furthermore, alumina has a high melting point, typically much higher than the catalyst's operating temperature, ensuring structural stability. Optionally, the spherical alumina support has a particle size of 2-4 mm, a specific surface area ≥200 m² / g, a bulk density of 1.2-1.4 g / cm³, a palladium content of 5-8 wt%, a platinum content of 1-2 wt%, and a filling rate of 1 t-400 g, meaning 400 g of particles per ton of gas processed. In other embodiments, the catalytic particle size can be adjusted to 1-5 mm, and the layer thickness to 2-6 cm.

[0073] Specifically, palladium-platinum catalyst particles are filled between adjacent catalytic honeycomb support layers 21 to form catalytic honeycomb support layers 21. Optionally, each catalytic honeycomb support layer 21 has a thickness of 4 cm.

[0074] In some embodiments, the processing method of the exhaust gas catalytic treatment device includes a step of preparing a catalytic particle layer 22. The catalytic particle layer 22 is prepared by an impregnation method, which can ensure uniformity of loading and enrich the load on the particle surface.

[0075] Specifically, the preparation steps of the catalytic particle layer 22 are as follows:

[0076] The preparation steps of the catalytic particle layer 22 include: first impregnating the raw material particles with a solution of palladium chloride and chloroplatinic acid, then pretreating them in air at a first temperature (e.g., 298℃≤first temperature≤302℃), wherein the raw material particles are spherical alumina substrates; then reducing them in a hydrogen atmosphere at a second temperature (e.g., 398℃≤second temperature≤402℃) to obtain finished particles with metallic active components; and placing the finished particles into the gaps between adjacent catalytic honeycomb carrier layers 21, so that they are in close contact with the corresponding catalytic honeycomb carrier layers 21.

[0077] For example, the active component is first impregnated with a solution of palladium chloride and chloroplatinic acid, then pretreated in air at 300°C for 2 hours, and then reduced at 400°C for 2 hours in a hydrogen atmosphere to obtain the metallic active component. These finished particles are placed into the gaps of the catalytic honeycomb carrier layer 21 by gravity filling or vibration compaction, and are in close contact with the catalytic honeycomb carrier layer 21. The finished particles can increase the active surface area of ​​the catalytic reaction, and also play a role in uniform airflow distribution and enhanced mass and heat transfer.

[0078] In this embodiment, the catalyst module 2 has a palladium-platinum alloy as the main catalyst in each catalyst layer. The honeycomb carrier is filled with an alumina coating and then loaded with palladium-platinum components, prepared through an impregnation-calcination process. The catalyst particles are spherical alumina substrates with palladium-platinum loaded on their surfaces, prepared through an impregnation-reduction process. This composition of the catalyst layers enhances the reaction activity and optimizes mass and heat transfer, enabling low-temperature start-up and long lifespan.

[0079] The exhaust gas catalytic treatment device 8 in this embodiment has the following advantages: the catalytic module 2 fully utilizes the high reactivity of palladium-platinum catalysts for hydrogen catalytic combustion, and combined with the multi-stage gas path of the multi-layer catalytic layer, it can greatly optimize the response speed and safety; the exhaust gas catalytic treatment device 8 adopts a modular and compact structure, including a multi-layer catalytic honeycomb carrier layer 21 and a catalytic particle layer 22 alternately arranged with the catalytic honeycomb carrier layer 21. The multi-layer layout provides a large specific surface area and uniform airflow distribution, which can ensure that the device has a small size and low pressure loss, and is suitable for space-constrained systems; the exhaust gas catalytic treatment device 8 is placed in a stainless steel main housing 4, and the two ends of the catalytic module 2 are equipped with sealing gaskets and quick-release clamps, which facilitates installation, disassembly and material replacement.

[0080] In addition to the aforementioned exhaust gas catalytic treatment device 8 and processing method, this invention also provides a fuel cell hydrogen removal system integrated into a fuel cell system, specifically a hydrogen fuel cell, and more specifically a proton exchange membrane fuel cell. This fuel cell hydrogen removal system includes an exhaust gas catalytic treatment device 8, which can specifically be the exhaust gas catalytic treatment device 8 provided in any of the above embodiments. The beneficial effects can be referred to the respective embodiments above. This fuel cell hydrogen removal system, through gas splitting, multi-stage mixing, and catalytic combustion, employs a gradient hydrogen removal strategy to achieve gradual elimination of hydrogen.

[0081] For details, please refer to the following: Figure 2 The hydrogen removal system of the fuel cell includes components such as fuel cell stack 5, water separator 6, recirculation branch 61, exhaust valve 7, and exhaust gas catalytic treatment device 8. These components are connected by pipes and valves to form a closed-loop control system.

[0082] The fuel cell stack 5 is located at the core of the system and produces exhaust gas after combustion. The anode outlet of the fuel cell stack 5 is connected to the first branch 51, and the cathode outlet of the fuel cell stack 5 is connected to the second branch 52. The first branch 51 discharges hydrogen exhaust gas, which requires hydrogen removal treatment. The second branch 52 discharges air exhaust gas. The outlet of the second branch 52 is connected to the inlet of the first air exhaust branch 521 and the inlet of the second air exhaust branch 522, further discharging exhaust gas in two separate paths and also serving to provide dilution air.

[0083] The inlet of water separator 6 is connected to the outlet of the first branch 51. In addition, water separator 6 is connected to a drain valve through guide vanes and a settling chamber, which serves to separate condensate.

[0084] The inlet of the exhaust gas catalytic converter 8 is connected to the outlet of the first air exhaust branch 521 and the first outlet of the water separator 6. The catalytic converter 8 plays a core role in catalytic combustion. The outlet of the exhaust gas catalytic converter 8 is connected to the second air exhaust branch 522 through the third branch 81. The third branch 81 is used to discharge the treated gas.

[0085] In operation, this fuel cell hydrogen removal system involves the exhaust gas from the anode outlet of the fuel cell stack 5 passing through a water separator 6. The exhaust gas is then mixed and diluted for the first time with the exhaust gas from the first air exhaust branch 521. This mixing process significantly dilutes the hydrogen concentration in the exhaust gas, achieving an initial reduction in hydrogen concentration and thus reducing the load on subsequent processing units. The mixed gas then enters the exhaust gas catalytic treatment device 8 for multi-layer catalytic combustion to remove hydrogen. This device, through a catalytic combustion reaction mechanism, under appropriate temperature and catalyst conditions, fully oxidizes the hydrogen in the exhaust gas into water vapor, further reducing the content of combustible components in the gas, thereby effectively improving system safety. The gas treated by the catalytic treatment device 8 is then mixed and diluted a second time with the exhaust gas from the second air exhaust branch 522. This secondary dilution process further reduces the volume fraction of hydrogen in the gas, minimizing the risk of hydrogen leakage and ensuring the environmental safety and operational reliability of the fuel cell system during operation. Finally, the gas is safely discharged through the second air exhaust branch 522. This multi-stage, progressive treatment and gradient hydrogen removal of the hydrogen exhaust gas ensures low-concentration hydrogen emissions.

[0086] Optionally, a first control unit is connected to the first branch 51 or the first air exhaust branch 521 to perform mass flow control, thereby adjusting the mixing ratio of the mixed gas entering the exhaust gas catalytic treatment device 8, so that the gas flow ratio supplied from the outlet of the first air exhaust branch 521 to the exhaust gas catalytic treatment device is within a preset range. For example, for the mixed gas entering the exhaust gas catalytic treatment device 8, the flow ratio of hydrogen exhaust gas received from the water separator 6 to air exhaust gas received from the first air exhaust branch 521 is approximately 1:8 to 1:12, so that the hydrogen gas fraction in the mixed gas is reduced to 0.1-0.4%, and the oxygen volume fraction is maintained at 12-16%, providing a suitable hydrogen-oxygen molar ratio for subsequent reactions, for example, approximately 1:6 to 1:10.

[0087] Optionally, the exhaust gas catalytic treatment unit 8 is also equipped with a temperature monitoring point and an automatic adjustment system connected to the controller to prevent overheating. For example, when the bed temperature exceeds 220°C, the dilution air flow rate is automatically increased or the inlet air flow rate is decreased to extend the catalyst life.

[0088] Optionally, the third branch 81 and the second air exhaust branch 522 are connected by a vortex mixer to achieve further cooling of the exhaust.

[0089] Furthermore, the fuel cell stack 5 has a hydrogen inlet 53 and an air inlet 54. The hydrogen inlet 53 is connected to a hydrogen source, and the air inlet 54 is connected to an air source. The second outlet of the water separator 6 is connected to the hydrogen inlet 53 of the fuel cell stack 5 via a recirculation branch 61, which serves to transport hydrogen exhaust gas.

[0090] At this time, the exhaust gas discharged from the anode outlet of the fuel cell stack 5 enters the water separator 6 through the first branch 51, and is split through the first outlet and the second outlet of the water separator 6. Part of it returns to the fuel cell stack 5 for recirculation, so as to realize the recovery and reuse of unreacted hydrogen, thereby improving the overall hydrogen utilization rate of the system and reducing fuel consumption. The other part is discharged to the exhaust gas catalytic treatment device 8 for hydrogen removal treatment.

[0091] Specifically, the water separator 6 employs a combination of cyclone separation and gravity settling, and is equipped with guide vanes and a settling chamber, achieving a separation efficiency of ≥95%. The separated condensate is periodically discharged through a drain valve. The water separator 6 is connected to the hydrogen inlet 53 of the fuel cell stack 5 via a recirculation branch 61, on which a recirculation pump is installed. For example, the exhaust gas from the water separator 6 contains approximately 0.8-2.8% hydrogen, approximately 60-80% nitrogen, and the remainder consists of water vapor and trace impurities.

[0092] Optionally, regarding the exhaust ratio of the first and second outlets of the water separator 6, the flow rate of the gas discharged from the second outlet of the water separator 6 is greater than the flow rate of the gas discharged from the first outlet to ensure hydrogen utilization. For example, approximately 85% of the dried gas separated by the water separator 6 is returned to the hydrogen inlet 53 of the fuel cell stack 5, i.e., the anode inlet of the fuel cell stack 5, via the second outlet through a recirculation pump for recycling; approximately 15% is discharged into the exhaust gas catalytic treatment device 8 through the first outlet for hydrogen removal treatment.

[0093] Furthermore, an exhaust valve 7 is installed between the first outlet of the water separator 6 and the inlet of the tail gas catalytic treatment unit. The exhaust valve 7 is used to promptly release the mixed gas discharged from the first outlet, which is rich in inert gases (such as nitrogen) and a small amount of unreacted hydrogen, preventing its continuous accumulation in the anode circuit. The exhaust valve 7 is communicatively connected to a controller, which controls the exhaust valve 7 to open intermittently, maximizing hydrogen utilization while removing impurities. For example, the exhaust valve 7 can open for 3-5 seconds every 30-60 seconds to achieve intermittent venting. Through a pre-stored program in the controller, the hydrogen removal process can be automatically adjusted to improve overall safety control and rapid response.

[0094] In addition, the outlet of exhaust valve 7 and the outlet of the first air exhaust branch 521 are connected to the inlet of exhaust gas catalytic treatment device 8.

[0095] This fuel cell hydrogen removal system achieves hydrogen removal through catalytic combustion of the exhaust gas catalytic treatment device. By combining a multi-layer catalytic layer structure of microchannel honeycomb carrier and palladium-platinum catalytic particles, quick-release clamps, and gradient treatment of exhaust gas diversion, pre-dilution, catalytic combustion, and secondary dilution, it can achieve efficient and safe hydrogen removal. For example, in exhaust gas with a hydrogen concentration of 2-5%, the conversion rate can reach over 99%.

[0096] The working principle of the fuel cell hydrogen removal system in this embodiment includes:

[0097] First, the anode exhaust gas of the fuel cell stack 5 enters the water separator 6 through the first branch 51.

[0098] Then, the discharged hydrogen-containing tail gas is mixed and diluted for the first time with the gas in the second branch 52. The gas in the second branch 52 comes from the cathode outlet of the fuel cell stack 5 and contains unreacted air with an oxygen volume fraction of 15-18%, a nitrogen volume fraction of about 78-80%, and a flow rate of about 150-250 standard liters per minute.

[0099] Next, the pre-diluted mixed gas enters the exhaust gas catalytic treatment device 8 for catalytic combustion. This exhaust gas catalytic treatment device 8 is connected to the upstream mixing pipeline via a flange. The reaction mechanism is as follows: This is a strongly exothermic reaction. In the tail gas catalytic treatment device 8, the gas passes sequentially through a composite catalytic bed consisting of a three-layer catalytic honeycomb carrier layer 21 and two-layer catalytic particle layers 22: the first honeycomb layer 211 mainly serves as a preheating and initial reaction layer, achieving a hydrogen conversion rate of 50-60%, with the bed temperature rising from ambient temperature to 60-80℃; the first particle layer 221 further improves the conversion rate to 75-85%, with the temperature rising to 90-120℃; the second honeycomb layer 212 increases the conversion rate to 85-92%, with the temperature rising to 110-150℃; the second particle layer 222 achieves a conversion rate of 90-95%, with the temperature rising to 130-180℃; the third honeycomb layer 213 serves as a refining unit, ultimately achieving a hydrogen conversion rate >93%, an outlet hydrogen integral <0.02%, and a bed outlet temperature stabilized at 140-200℃. The exhaust gas catalytic treatment unit 8 is equipped with a temperature monitoring point and an automatic adjustment system connected to the controller. When the bed temperature exceeds 220℃, it automatically increases the dilution air flow or decreases the inlet air flow to ensure long-term stable operation of the catalyst. The expected service life of the catalyst is ≥8000 hours. After deactivation, the catalytic component can be replaced by removing the clamps.

[0100] Finally, the treated high-temperature gas is discharged from the outlet of the tail gas catalytic treatment device 8. Its main components are water vapor (volume fraction 8-12%), carbon dioxide (<0.1%), nitrogen (80-85%), and oxygen (5-10%). This gas is then mixed again with the low-temperature gas from the second air exhaust branch 522 for a second dilution and cooling. Furthermore, the third branch 81 and the second air exhaust branch 522 are connected by a vortex mixer, achieving a temperature reduction to 40-60℃ and further reducing the hydrogen volume fraction to <0.005%, far below 1 / 800 of the hydrogen explosion limit of 4%. The gas is then safely discharged through the exhaust outlet on the second air exhaust branch 522, achieving full-process safety control from source to emission. The total pressure loss of the entire gradient hydrogen removal process is ≤3kPa, and the system response time is ≤10s. Under various operating conditions, the emitted hydrogen concentration can be guaranteed to meet safety requirements, significantly improving the safety and reliability of the fuel cell system.

[0101] The hydrogen removal system for fuel cells in this embodiment has the following advantages: Through the structural design of the compact catalytic combustion tail gas catalytic treatment device 8, the composition of the internal catalytic materials, and the supporting gradient hydrogen removal method, and through the combination of multi-layer palladium-platinum honeycomb carriers and catalytic particles, as well as multi-stage gas path treatment (splitting, dilution, combustion, and secondary dilution), it achieves a high hydrogen conversion rate (>93%), rapid response (≤10s), and low concentration emissions (<0.05%). This solves the problems of high hydrogen concentration, low removal efficiency, incomplete reaction, slow response speed, lag in regulation, complex structure, large size, and inconvenient maintenance in existing fuel cell tail gas hydrogen treatment. It can save equipment maintenance costs, simplify the operation process, improve the hydrogen removal rate (>93%) by increasing the catalytic combustion efficiency, and enhance the safety and reliability of the system.

[0102] It should be noted that when an element is referred to as "fixing" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as "connecting" another element, it can be directly connected to the other element or there may be an intervening element. Furthermore, in the description of this invention, unless otherwise stated, "multiple," "multiple roots," and "multiple groups" mean two or more.

[0103] The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0104] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0105] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0106] The exhaust gas catalytic treatment device and its processing method, as well as the fuel cell hydrogen removal system provided by this invention, have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A tail gas catalytic treatment device, characterized in that, It includes a catalytic module (2); the catalytic module (2) includes multiple catalytic honeycomb carrier layers (21) arranged sequentially along a preset exhaust direction, and catalytic particle layers (22) located between each two adjacent catalytic honeycomb carrier layers (21).

2. The exhaust gas catalytic treatment device according to claim 1, characterized in that, The three catalytic honeycomb carrier layers (21) are respectively the first honeycomb layer (211), the second honeycomb layer (212) and the third honeycomb layer (213) arranged sequentially along the exhaust direction. The two catalytic particle layers (22) are a first particle layer (221) and a second particle layer (222) arranged sequentially along the exhaust direction. The two sides of the first particle layer (221) are respectively attached to the first honeycomb layer (211) and the second honeycomb layer (212), and the two sides of the second particle layer (222) are respectively attached to the second honeycomb layer (212) and the third honeycomb layer (213).

3. The exhaust gas catalytic treatment device according to claim 1, characterized in that, It also includes the main housing (4), the first housing (1), and the second housing (3); The catalytic module (2) is built into the main housing (4). The first housing (1) and the second housing (3) are detachably connected to both sides of the main housing (4) and are respectively sealed to both sides of the catalyst module (2); Along the exhaust direction, the first housing (1), the main housing (4), and the second housing (3) are arranged and connected in sequence. The gas enters the catalytic module (2) through the inlet on the first housing (1) and is discharged through the outlet on the second housing (3).

4. The exhaust gas catalytic treatment device according to claim 3, characterized in that, The first housing (1) and the second housing (3) are respectively connected to the main housing (4) by clamps, and the first housing (1) and the second housing (3) are respectively sealed to the catalyst module (2) by sealing gaskets.

5. The exhaust gas catalytic treatment device according to any one of claims 1 to 4, characterized in that, The catalytic honeycomb carrier layer (21) includes a honeycomb carrier, the interior of which is filled with an alumina coating and then loaded with a palladium-platinum component.

6. The exhaust gas catalytic treatment device according to claim 5, characterized in that, The catalytic honeycomb carrier layer (21) has a microchannel structure and is made of cordierite ceramic substrate. The number of channels in the catalytic honeycomb carrier layer (21) ranges from 200 to 600 mesh. In the palladium-platinum composition of the catalytic honeycomb carrier layer (21), the palladium content is 2-3 g / L carrier and the platinum content is 0.5-1 g / L carrier.

7. The exhaust gas catalytic treatment device according to any one of claims 1 to 4, characterized in that, The particles of the catalytic particle layer (22) are made of spherical alumina substrate and the surface is loaded with palladium-platinum components.

8. The exhaust gas catalytic treatment device according to claim 7, characterized in that, The spherical alumina substrate has a particle size of 2-4 mm, a specific surface area of ​​≥200 m² / g, a bulk density of 1.2-1.4 g / cm³, a surface-loaded palladium content of 5-8 wt%, a platinum content of 1-2 wt%, and a filling rate of 1 t-400 g.

9. A processing method for a tail gas catalytic treatment device, characterized in that, Applied to the tail gas catalytic treatment device according to any one of claims 1 to 8, the processing method includes the preparation step of the catalytic honeycomb carrier layer (21); The preparation steps of the catalytic honeycomb carrier layer (21) include: The honeycomb carrier is first impregnated in a nitrate solution containing palladium-platinum precursors, drained, and then calcined to form a uniformly distributed catalytic active layer on the honeycomb carrier.

10. The processing method according to claim 9, characterized in that, In the process of draining and then calcining, the calcination temperature is T, where 448℃≤T≤452℃, and the calcination time is t hours, where 2.8≤t≤3.

2.

11. A processing method for a tail gas catalytic treatment device, characterized in that, Applied to the tail gas catalytic treatment device according to any one of claims 1 to 8, the processing method includes the step of preparing the catalytic particle layer (22); The preparation steps of the catalytic particle layer (22) include: The raw material particles were first impregnated with a solution of palladium chloride and chloroplatinic acid, and then pretreated in air at a first temperature. The raw material particles were spherical alumina substrates. Then, the particles are reduced at a second temperature in a hydrogen atmosphere to obtain finished particles with metallic active components. The finished particles are placed in the gap between adjacent catalytic honeycomb carrier layers (21) and are in close contact with the corresponding catalytic honeycomb carrier layer (21).

12. The processing method according to claim 11, characterized in that, 298℃≤first temperature≤302℃, 398℃≤second temperature≤402℃.

13. The processing method according to claim 11, characterized in that, The finished particles are placed into the gaps between adjacent catalytic honeycomb carrier layers (21) by gravity filling or vibration compaction.

14. A hydrogen removal system for a fuel cell, characterized in that, Includes the exhaust gas catalytic treatment device according to any one of claims 1 to 8; The fuel cell stack (5) has its anode outlet connected to the first branch (51) and its cathode outlet connected to the second branch (52). The outlet of the second branch (52) is connected to the inlet of the first air exhaust branch (521) and the inlet of the second air exhaust branch (522). The water separator (6) has its inlet connected to the outlet of the first branch (51). The outlet of the first air exhaust branch (521) and the first outlet of the water separator (6) are both connected to the inlet of the exhaust gas catalytic treatment device. The outlet of the exhaust gas catalytic treatment device is connected to the second air exhaust branch (522) through the third branch (81).

15. The fuel cell hydrogen removal system according to claim 14, characterized in that, A first control unit is connected to the first branch (51) or the first air exhaust branch (521) to control the flow rate of the gas in the first branch (51) or the first air exhaust branch (521), so that the ratio of the gas flow rate supplied from the outlet of the first air exhaust branch (521) to the exhaust gas catalytic treatment device is within a preset range.

16. The fuel cell hydrogen removal system according to claim 15, characterized in that, The ratio of the flow rate of hydrogen exhaust gas received by the exhaust gas catalytic treatment device from the water separator (6) to the flow rate of air exhaust gas received from the first air exhaust branch (521) is 1:8-1:

12.

17. The fuel cell hydrogen removal system according to claim 14, characterized in that, The third branch (81) and the second air exhaust branch (522) are connected by a vortex mixer.

18. The fuel cell hydrogen removal system according to claim 14, characterized in that, The second outlet of the water separator (6) is connected to the hydrogen inlet (53) of the fuel cell stack (5) via a recirculation branch (61).

19. The fuel cell hydrogen removal system according to claim 18, characterized in that, The flow rate of gas discharged from the water separator (6) through the second outlet is greater than the flow rate of gas discharged through the first outlet.

20. The fuel cell hydrogen removal system according to any one of claims 14 to 19, characterized in that, An exhaust valve (7) is also provided between the first outlet of the water separator (6) and the inlet of the exhaust gas catalytic treatment device; the exhaust valve (7) is communicatively connected to the controller, and the controller controls the exhaust valve (7) to open intermittently.

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