Electrochemical device
By using a porous structure reducing metal or alloy material in an electrochemical device to react with water vapor to generate hydrogen, protecting the catalyst, the functional failure problem caused by water vapor intrusion is solved, and the full utilization and cost reduction of water vapor are achieved.
Patent Information
- Application Number
- CN202420389832.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-29
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-02-28
AI Technical Summary
Prior Art In solid oxide fuel cells and electrolytic cells, the catalyst has functional failure due to water vapor intrusion caused by emergency stop or failure, and the water vapor is not fully utilized, which is complex and costly.
Design an electrochemical device, including a first hydrogen generation device, which is filled with a porous structure reducing metal or alloy material, reacts with water vapor to generate hydrogen, protects the catalyst in the electrochemical stack, and when the reducing fluid is restored Recycle materials.
Effectively consume water vapor, protect the catalyst, avoid oxidative damage, reduce costs, and improve the service life and efficiency of the device.
Smart Images
Figure CN222261132U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electrochemistry, in particular to an electrochemical device. Background Art
[0002] The mutual conversion between electrical energy and chemical energy is achieved through various electrochemical devices, such as fuel cells, electrolyzers, etc. Common fuel cells include alkaline fuel cells (AFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFF), proton exchange membrane fuel cells (PEMFC), direct methanol fuel cells (DMFC), solid oxide fuel cells (SOFC), etc.; common electrolyzers include alkaline electrolyzers (AWE), proton exchange membrane water electrolyzers (PEMWE), anion exchange membrane water electrolyzers (AEMWE), solid oxide electrolyzers (SOEC), etc. Among them, solid oxide fuel cells (SOFC) and solid oxide electrolyzers (SOEC) can be collectively referred to as solid oxide cells (SOC). Solid oxide cells (SOC) are advanced electrochemical energy conversion devices with broad application prospects in the fields of clean energy generation and CO2 conversion. Solid oxide fuel cell (SOFC) is an energy conversion device that can directly convert chemical energy stored in fuel and oxidant into electrical energy. It has a high operating temperature, usually in the range of 700-1000℃, so its waste heat can be used to achieve combined heat and power while generating electricity, and the energy utilization efficiency can be as high as 90%. Solid oxide electrolyzer (SOEC) is an electrochemical energy conversion device that converts electrical energy and thermal energy into chemical energy, and its reaction is the reverse reaction of solid oxide fuel cell. As one of the main technical routes for hydrogen production by electrolysis of water today, SOEC usually operates at 700-850℃, and the electrolysis efficiency is as high as 85-95%. Solid oxide fuel cells and solid oxide electrolyzers can use the same electrochemical stack for reaction. The difference is that the anode side of the solid oxide fuel cell serves as the cathode side in the solid oxide electrolyzer. For example, on the anode side of the solid oxide fuel cell, hydrogen molecules (H2) lose electrons (e) under the catalytic action of the anode. - ) is oxidized to H + , while hydrogen ions (H + ) receives electrons (e - ) is reduced to hydrogen (H2).
[0003] In SOFC, when using fuels other than hydrogen, the fuel usually needs to be reformed by steam reforming, partial oxidation, catalytic cracking, etc. before entering the anode; in SOEC, water vapor and hydrogen are passed together as reaction gases to the SOEC cathode. The catalysts in the SOFC anode and SOEC cathode are usually easily oxidized metals or alloys (such as nickel). During the normal operation of the electrochemical stack, the catalyst is always in a reduced state because it is in a reducing atmosphere (H2). When the system stops supplying reducing fluid (here, the reducing fluid refers to the fuel to the anode side of the SOFC and the hydrogen to the cathode side of the SOEC, the same below) due to emergency stop or failure, the catalyst in the electrochemical stack will inevitably be invaded by external gases, causing the catalyst to fail. At present, the existing technology usually adopts methods such as sacrificial metal, rapid cooling, and inert gas to prevent the electrochemical stack from being invaded by external gases and causing the catalyst function to fail. However, the existing technology still has many problems: ① The operation is complicated and the cost is high; ② Water vapor is not fully utilized; ③ The hazards and effects of water vapor are not fully considered. Water vapor will cause certain intrusion and damage to the electrochemical stack, for example, oxidizing the catalyst on the anode side of the SOFC or the catalyst on the cathode side of the SOEC.
[0004] Therefore, it is very necessary to develop an electrochemical device to make full use of water vapor while avoiding catalyst failure caused by water vapor oxidation. Utility Model Content
[0005] Based on the defects of the prior art, the purpose of the utility model is to provide an electrochemical device.
[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:
[0007] An electrochemical device includes an electrochemical stack and a first hydrogen generating device, wherein the electrochemical stack has a first reaction zone inlet, a first reaction zone and a first reaction zone outlet, wherein the first reaction zone inlet and the first reaction zone outlet are respectively connected to the first reaction zone, the first reaction zone inlet of the electrochemical stack is connected to the outlet of the first hydrogen generating device, the first hydrogen generating device is a structure that is hollow inside and open at both ends, the inlet of the first hydrogen generating device is used to receive a reducing fluid and / or water vapor, the first hydrogen generating device is filled with a first hydrogen generating material, the material of the first hydrogen generating material is a reducing metal or a reducing alloy, and the first hydrogen generating material is used to react with water vapor.
[0008] As a preferred embodiment of the present invention, the first hydrogen generating material is a porous structure, and the porosity of the first hydrogen generating material is 10-300ppi.
[0009] As a preferred embodiment of the utility model, the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the first hydrogen generating material in the first hydrogen generating device is P1, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the first reaction zone is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the first hydrogen generating device is P3, P3>P1; when the inlet of the first hydrogen generating device does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack is P4, P4>P2. If P3<P1 when the electrochemical device operates normally, the first hydrogen generating material in the first hydrogen generating device has been oxidized, and when the inlet of the first hydrogen generating device does not receive the reducing fluid due to an emergency stop or failure of the electrochemical device, it no longer has the ability to react with water vapor to generate hydrogen protection gas; if P4<P2 when the inlet of the first hydrogen generating device does not receive the reducing fluid, the catalyst in the reaction zone of the electrochemical stack 1 is oxidized, causing irreversible damage.
[0010] As a preferred embodiment of the present invention, the electrochemical stack is a solid oxide fuel cell, and the electrochemical device further comprises a reformer, wherein the outlet of the reformer, the first hydrogen generating device and the inlet of the first reaction zone of the electrochemical stack are connected in sequence.
[0011] As a preferred embodiment of the present invention, the electrochemical stack is a solid oxide electrolysis cell, and the electrochemical device further comprises a mixer, wherein the outlet of the mixer, the first hydrogen generating device and the inlet of the first reaction zone of the electrochemical stack are connected in sequence.
[0012] As a preferred embodiment of the present utility model, the outlet of the first reaction zone of the electrochemical stack is connected to a second hydrogen generating device, the second hydrogen generating device is a structure that is hollow inside and open at both ends, and a second hydrogen generating material is arranged in the second hydrogen generating device. The material of the second hydrogen generating material is a reducing metal or a reducing alloy, and the second hydrogen generating material is used to react with water vapor.
[0013] Furthermore, the second hydrogen generating material has a porous structure, and the porosity of the second hydrogen generating material is 10-300 ppi.
[0014] Furthermore, the electrochemical stack is a solid oxide fuel cell, and the electrochemical device also includes a burner. The outlet of the first reaction zone of the electrochemical stack, the second hydrogen generation device, and the inlet of the burner are connected in sequence.
[0015] Furthermore, the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the second hydrogen generating material in the second hydrogen generating device is P5, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the first reaction zone is P2; when the electrochemical device is operating normally, the hydrogen partial pressure in the second hydrogen generating device is P6, P6>P5; when the inlet of the first hydrogen generating device is not receiving, the hydrogen partial pressure in the first reaction zone of the electrochemical stack is P4, P4>P2. If P6<P5 when the electrochemical device is operating normally, the second hydrogen generating material in the second hydrogen generating device has been oxidized, and when the inlet of the first hydrogen generating device does not receive the reducing fluid due to an emergency stop or failure of the electrochemical device, it is unable to consume the refluxed water vapor and provide sufficient hydrogen, and loses the protective effect on the electrochemical stack; if P4<P2 when the inlet of the second hydrogen generating device does not receive the reducing fluid, the catalyst in the reaction zone of the electrochemical stack 1 is oxidized, causing irreversible damage.
[0016] It can be understood that in the present invention, the hydrogen partial pressure in the fuel cell reaction zone and the hydrogen partial pressure at the hydrogen generation device are tested as follows: the concentration of hydrogen in the gas in the corresponding area is obtained by electron bombardment mass spectrometry, and then the hydrogen partial pressure is calculated according to the following formula: hydrogen partial pressure = hydrogen concentration * standard atmospheric pressure.
[0017] Compared with the prior art, the beneficial effects of the utility model are:
[0018] The utility model sets a first hydrogen generating device at the entrance of the first reaction zone of the electrochemical stack. When the electrochemical device interrupts the supply of reducing fluid, the first hydrogen generating material filled in the first hydrogen generating device is used to react with water vapor to consume the water vapor. At the same time, the hydrogen generated by the reaction enters the electrochemical stack as a protective gas, which can protect the catalyst in the electrochemical stack, thereby avoiding the failure of the catalyst caused by water vapor oxidation and making full use of the water vapor. When the electrochemical device resumes the supply of reducing fluid, the oxidized first hydrogen generating material can be reduced by the reducing fluid, so that the first hydrogen generating material can be recycled, with a long service life and low cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of the structure of an electrochemical device provided in one embodiment of the utility model;
[0020] Figure 2 A schematic structural diagram of an electrochemical device provided in another embodiment of the utility model;
[0021] Figure 3 This is a graph showing the voltage variation trend of the fuel cell provided by the utility model before and after the supply of reducing fluid is stopped.
[0022] In the figure, 1-electrochemical stack, 2-first hydrogen generating device, 3-first hydrogen generating material, 4-reformer, 5-mixer, 6-second hydrogen generating device, 7-second hydrogen generating material, 8-burner, 9-pressurized storage system. DETAILED DESCRIPTION
[0023] In order to better illustrate the purpose, technical solutions and advantages of the utility model, the utility model will be further described below in conjunction with specific embodiments and comparative examples, the purpose of which is to understand the content of the utility model in detail, rather than to limit the utility model. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0024] See also Figure 1-2 The utility model provides an electrochemical device, including an electrochemical stack 1, wherein the electrochemical stack 1 has a first reaction zone inlet, a first reaction zone and a first reaction zone outlet, wherein the first reaction zone inlet and the first reaction zone outlet are respectively connected to the first reaction zone, and the first hydrogen generating device 2 is a structure that is hollow inside and open at both ends, wherein the first reaction zone inlet of the electrochemical stack 1 is connected to the outlet of the first hydrogen generating device 2, and the inlet of the first hydrogen generating device 2 is used to receive a reducing fluid and / or water vapor, and the reducing fluid and / or water vapor flows through the first hydrogen generating device 2 and the first reaction zone of the electrochemical stack in sequence, and then flows out from the outlet of the first reaction zone. The first hydrogen generating device 2 is filled with a first hydrogen generating material 3, wherein the material of the first hydrogen generating material 3 is a reducing metal or a reducing alloy, and the first hydrogen generating material 3 can react with water vapor.
[0025] When the electrochemical device fails and the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the water vapor is not stopped in time, resulting in a rapid increase in the water content of the fluid entering through the inlet of the first reaction zone of the electrochemical stack 1, which will cause certain intrusion and damage to the electrochemical stack 1. The utility model sets the first hydrogen generating device 2 to be connected to the inlet of the first reaction zone of the electrochemical stack 1, and utilizes the first hydrogen generating material 3 filled in the first hydrogen generating device 2 to react with the water vapor, thereby consuming the water vapor. The general reaction formula is: xJ+yH2O→J x O y +yH2, where J represents the first hydrogen generating material 3; the hydrogen generated by the reaction enters the electrochemical stack 1 as a protective gas to protect the catalyst in the electrochemical stack 1. When the electrochemical device resumes the supply of reducing fluid, J x O y The first hydrogen generating material 3 can be reduced by the reducing fluid, can be recycled, has a long service life and is low in cost.
[0026] In one embodiment, the first hydrogen generating material 3 is a porous structure, and the porosity of the first hydrogen generating material 3 is 10-300 ppi.
[0027] The inventor has found through research that the porous structure of the first hydrogen generating material 3 has a large specific surface area, which can accelerate the reaction rate of the first hydrogen generating material 3 with water vapor. If the porosity of the first hydrogen generating material 3 is less than 10ppi, the specific surface area of the first hydrogen generating material 3 is too small, the reaction rate of the first hydrogen generating material 3 with water vapor is too small, and sufficient hydrogen cannot be generated, and the protection effect on the electrochemical stack 1 is poor; if the porosity of the first hydrogen generating material 3 is greater than 300ppi, the path in the pores of the first hydrogen generating material 3 is tortuous and long, which increases the pressure loss at the entrance of the first reaction zone of the electrochemical stack 1, increases the difficulty of gas supply at the entrance of the first reaction zone of the electrochemical stack 1, and increases the energy consumption of the gas supply device.
[0028] It should be understood that the reducing fluid described in the present invention can be hydrogen, or a mixture of hydrogen and methane; if the electrochemical stack is a solid oxide fuel cell, the first reaction zone is the anode reaction zone; if the electrochemical stack is a solid oxide electrolysis cell, the first reaction zone is the cathode reaction zone.
[0029] In one embodiment, the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the first hydrogen generating material 3 in the first hydrogen generating device 2 is P1, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the reaction zone of the electrochemical stack 1 is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the first hydrogen generating device 2 is P3, and P3>P1; when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack 1 is P4, and P4>P2.
[0030] Through research, it is found that the utility model adjusts the loading position and loading amount of the first hydrogen generating material 3 so that P3>P1, P4>P2, thereby ensuring that the first hydrogen generating material 3 remains in a reduced state when the device is operating normally, and when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid due to an emergency stop or failure of the electrochemical device, the first hydrogen generating material 3 can continue to react with water vapor to generate hydrogen protective gas. If P3<P1 during normal operation of the electrochemical device, the first hydrogen generating material 3 in the first hydrogen generating device 2 has been oxidized, and when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid due to an emergency stop or failure of the electrochemical device, it no longer has the ability to react with water vapor to generate hydrogen protective gas; if P4<P2 when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the catalyst in the reaction zone of the electrochemical stack 1 is oxidized, causing irreversible damage.
[0031] In one embodiment, the electrochemical stack 1 is a solid oxide fuel cell, and the electrochemical device further comprises a reformer 4, the outlet of the reformer 4, the first hydrogen generating device 2 and the inlet of the first reaction zone of the electrochemical stack 1 are connected in sequence.
[0032] If the electrochemical stack 1 is a solid oxide fuel cell, the inlet of the first reaction zone of the electrochemical stack 1 is the anode inlet, and the outlet of the first reaction zone of the electrochemical stack 1 is the anode outlet. The reaction gas in the reformer 4 usually includes water vapor and a reducing fluid. Once the electrochemical device stops suddenly or fails, the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, and the water vapor in the reformer 4 flows directly to the anode of the solid oxide fuel cell, which will cause certain damage to the anode structure of the fuel cell. The utility model sets the first hydrogen generating device 2 between the outlet of the reformer 4 and the inlet of the first reaction zone of the electrochemical stack 1. When the electrochemical device stops suddenly or fails, the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the first hydrogen generating material 3 can consume water vapor and generate hydrogen at the same time. The generated hydrogen enters the anode of the gas battery, which can play a good protective role.
[0033] In one embodiment, the electrochemical device is a solid oxide electrolysis cell, and the electrochemical device further comprises a mixer 5, and an outlet of the mixer 5, a first hydrogen generation device 2 and an inlet of a first reaction zone of the electrochemical stack 1 are connected in sequence.
[0034] If the electrochemical stack 1 is a solid oxide electrolytic cell, the inlet of the first reaction zone of the electrochemical stack 1 is the cathode inlet of the solid oxide electrolytic cell, and the outlet of the first reaction zone of the electrochemical stack 1 is the cathode outlet of the solid oxide electrolytic cell. The reaction gas of the mixer 5 usually includes water vapor and a reducing fluid. Once the electrochemical device stops suddenly or stops due to a fault, the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, and the water vapor in the mixer 5 flows to the cathode of the solid oxide electrolytic cell through the first hydrogen generating device 2, which will cause certain damage to the cathode structure of the electrolytic cell. The utility model arranges the first hydrogen generating device 2 between the outlet of the mixer 5 and the inlet of the first reaction zone of the electrochemical stack 1. When the electrochemical device stops suddenly or stops due to a fault, the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the first hydrogen generating material 3 can consume water vapor and generate hydrogen at the same time. The generated hydrogen enters the cathode of the electrolytic cell, which can play a good protective role.
[0035] Specifically, the electrochemical device also includes a pressurized storage system 9. The outlet of the first reaction zone of the electrochemical stack 1, the second hydrogen generating device 6, and the inlet of the pressurized storage system 9 are connected in sequence. The pressurized storage system 9 is used to store the gas output by the second hydrogen generating device 6.
[0036] In one embodiment, the outlet of the first reaction zone of the electrochemical stack 1 is connected to a second hydrogen generating device 6. The second hydrogen generating device 6 is a structure that is hollow inside and open at both ends. A second hydrogen generating material 7 is arranged in the second hydrogen generating device 6. The material of the second hydrogen generating material 7 is a reducing metal or a reducing alloy. The second hydrogen generating material 7 can react with water vapor.
[0037] When the electrochemical device fails so that the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, water vapor reflux is likely to occur at the outlet of the first reaction zone of the electrochemical stack 1, and the water vapor reflux may cause certain intrusion and damage to the electrochemical stack 1. The utility model sets a second hydrogen generating device 6 connected to the outlet of the first reaction zone of the electrochemical stack 1, and utilizes the second hydrogen generating material 7 filled in the second hydrogen generating device 6 to react with the refluxed water vapor, consume the water vapor and react with the water vapor to produce hydrogen protection gas, thereby preventing the water vapor from refluxing to the electrochemical stack 1 and avoiding damage to the electrochemical stack 1.
[0038] Specifically, the second hydrogen generating material 7 is a porous structure, and the porosity of the second hydrogen generating material 7 is 10-300 ppi.
[0039] The inventor has found through research that the second hydrogen generating material 7 with a porous structure has a large specific surface area, which can accelerate the reaction rate of the second hydrogen generating material 7 with water vapor. If the porosity of the second hydrogen generating material 7 is less than 10ppi, the specific surface area of the second hydrogen generating material 7 is too small, and the reaction rate of the second hydrogen generating material 7 with water vapor is too small, which is not enough to quickly consume the refluxed water vapor, and cannot provide sufficient hydrogen, and the protection effect on the electrochemical stack 1 is poor; if the porosity of the second hydrogen generating material 7 is greater than 300ppi, the path in the pores of the second hydrogen generating material 7 is tortuous and long, which increases the pressure loss at the outlet of the first reaction zone of the electrochemical stack 1, on the one hand, increases the energy consumption of the gas supply device, and on the other hand, increases the operating pressure of the electrochemical stack 1, which is easy to cause its sealing failure.
[0040] Specifically, the electrochemical stack is a solid oxide fuel cell, and the electrochemical device further includes a burner 8. The outlet of the first reaction zone of the electrochemical stack 1, the second hydrogen generation device 6, and the inlet of the burner 8 are connected in sequence.
[0041] Specifically, the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the second hydrogen generating material 7 in the second hydrogen generating device 6 is P5, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the reaction zone of the electrochemical stack 1 is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the second hydrogen generating device 6 is P6, and P6>P5; when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack 1 is P4, and P4>P2.
[0042] Through research, it is found that the utility model can ensure that the second hydrogen generating material 7 remains in a reduced state when the device is operating normally by adjusting the loading position and loading amount of the second hydrogen generating material 7 so that P6>P5, P4>P2. When the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the second hydrogen generating material 7 can continue to react with water vapor to generate hydrogen protective gas. If P6<P5 during the normal operation of the electrochemical device, the second hydrogen generating material 7 in the second hydrogen generating device 6 has been oxidized. When the inlet of the first hydrogen generating device 2 does not receive the reducing fluid due to an emergency stop or failure of the electrochemical device, the refluxed water vapor cannot be consumed and sufficient hydrogen cannot be provided, and the protective effect on the electrochemical stack 1 is lost; if P4<P2 when the inlet of the second hydrogen generating device 6 does not receive the reducing fluid, the catalyst in the reaction zone of the electrochemical stack 1 is oxidized, causing irreversible damage.
[0043] In the present invention, the reducing metal may be any one of iron, nickel and cobalt, and the components of the reducing alloy include at least two of iron, nickel and cobalt.
[0044] The present invention provides the following examples and comparative examples to facilitate understanding of the present invention. The present invention provides these examples but is not intended to limit the scope of the claims. The experimental reagents and instruments involved in the implementation of the present invention are all commonly used common reagents and instruments unless otherwise specified.
[0045] Example 1
[0046] This embodiment provides an electrochemical device, the structure of which is as follows Figure 1 shown.
[0047] The electrochemical device includes an electrochemical stack 1, a first hydrogen generating device 2, a reformer 4, a second hydrogen generating device 6 and a burner 8. The electrochemical stack 1 has a first reaction zone inlet, a first reaction zone and a first reaction zone outlet. The first reaction zone inlet and the first reaction zone outlet are respectively connected to the first reaction zone. The electrochemical stack 1 is a solid oxide fuel cell, and the first reaction zone is an anode reaction zone. The first hydrogen generating device 2 is a structure that is hollow inside and open at both ends, and the second hydrogen generating device 6 is a structure that is hollow inside and open at both ends. The outlet of the reformer 4, the first hydrogen generating device 2 and the first reaction zone inlet of the electrochemical stack 1 are connected in sequence. The first reaction zone outlet of the electrochemical stack 1, the second hydrogen generating device 6 and the inlet of the burner 8 are connected in sequence. The first hydrogen generating device 2 is filled with a first hydrogen generating material 3, and the second hydrogen generating device 6 is filled with a second hydrogen generating material 7.
[0048] The thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the first hydrogen generating material 3 in the first hydrogen generating device 2 is P1, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the reaction zone of the electrochemical stack 1 is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the first hydrogen generating device 2 is P3, and P3>P1; when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack 1 is P4, and P4>P2.
[0049] The thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the second hydrogen generating material 7 in the second hydrogen generating device 6 is P5; when the electrochemical device operates normally, the hydrogen partial pressure in the second hydrogen generating device 6 is P6, and P6>P5; when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack 1 is P4, and P4>P2.
[0050] The material of the first hydrogen generating material 3 is iron, and the porosity of the first hydrogen generating material 3 is 110 ppi; the material of the second hydrogen generating material 7 is iron, and the porosity of the second hydrogen generating material 7 is 110 ppi.
[0051] Example 2
[0052] This embodiment provides an electrochemical device, the structure of which is as follows Figure 2 shown.
[0053] The electrochemical device includes an electrochemical stack 1, a first hydrogen generating device 2, a mixer 5, a second hydrogen generating device 6 and a pressurized storage system 9. The electrochemical stack 1 has a first reaction zone inlet, a first reaction zone and a first reaction zone outlet. The first reaction zone inlet and the first reaction zone outlet are respectively connected to the first reaction zone. The electrochemical stack 1 is a solid oxide electrolysis cell, and the first reaction zone is a cathode reaction zone. The first hydrogen generating device 2 is a structure that is hollow inside and open at both ends, and the second hydrogen generating device 6 is a structure that is hollow inside and open at both ends. The outlet of the mixer 5, the first hydrogen generating device 2 and the first reaction zone inlet of the electrochemical stack 1 are connected in sequence. The first reaction zone outlet of the electrochemical stack 1, the second hydrogen generating device 6 and the inlet of the pressurized storage system 9 are connected in sequence. The first hydrogen generating device 2 is filled with a first hydrogen generating material 3, and the second hydrogen generating device 6 is filled with a second hydrogen generating material 7.
[0054] The thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the first hydrogen generating material 3 in the first hydrogen generating device 2 is P1, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the reaction zone of the electrochemical stack 1 is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the first hydrogen generating device 2 is P3, and P3>P1; when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack 1 is P4, and P4>P2.
[0055] The thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the second hydrogen generating material 7 in the second hydrogen generating device 6 is P5; when the electrochemical device operates normally, the hydrogen partial pressure in the second hydrogen generating device 6 is P6, and P6>P5; when the inlet of the first hydrogen generating device 2 does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack 1 is P4, and P4>P2.
[0056] The material of the first hydrogen generating material 3 is iron-nickel alloy (iron and nickel ratio 1:1), and the porosity of the first hydrogen generating material 3 is 60ppi; the material of the second hydrogen generating material 7 is iron-nickel alloy (iron and nickel ratio 1:1), and the porosity of the second hydrogen generating material 7 is 60ppi.
[0057] Comparative Example 1
[0058] The difference between this comparative example and Example 1 is that the first hydrogen generating material is not loaded in the first hydrogen generating device 2, and the second hydrogen generating material is not loaded in the second hydrogen generating device 6.
[0059] The functions of the first hydrogen generating device 2 and the second hydrogen generating device 6 in the electrochemical devices of the above-mentioned embodiment 1 and comparative example 1 are verified. Before the verification, the electrochemical device is applied to a solid oxide fuel cell (SOFC) system. The verification steps are as follows:
[0060] The SOFC system is in a normal operating insulation state (660°C), the reducing fluid supplied is natural gas and water vapor, the corresponding molar flow ratio is 1:3, and the reformer outlet temperature is 440°C. The internal temperature of the first hydrogen generating device 2 is 790°C, and the corresponding internal fluid composition is H2O (54.24%), CH4 (15.55%), H2 (23.94%), CO2 (5.95%), CO (0.31%), that is, the hydrogen partial pressure P3 in the first hydrogen generating device 2 is 0.24 bar, while the thermodynamic equilibrium hydrogen partial pressure P1 of the first hydrogen generating material 3 undergoing oxidation reaction is 0.03 bar, P3>P1, which indicates that the first hydrogen generating material 3 is in a reduced state.
[0061] An emergency stop command is issued to the SOFC system, the reducing fluid is automatically cut off, the system is in a natural cooling state, and a DC-DC converter is used to detect the open circuit voltage of the electrochemical stack 1. The test results are as follows Figure 3 shown.
[0062] from Figure 3 It can be seen that after the supply of the reducing fluid is stopped, the voltage value of Example 1 is significantly greater than the voltage value of Comparative Example 1. Since the open circuit voltage is directly related to the hydrogen partial pressure in the reaction zone, at the same temperature, the higher the open circuit voltage, the higher the hydrogen partial pressure. It can be seen that the hydrogen generated by the reaction of the first hydrogen generating material 3 with water vapor in Example 1 enters the anode of the fuel cell, thereby making the hydrogen partial pressure of the anode higher, which plays a role in protecting the anode structure of the electrochemical stack 1.
[0063] The devices of the above-mentioned embodiments 1-2 were tested as follows:
[0064] 1. Install the first hydrogen generating device filled with the first hydrogen generating material or the second hydrogen generating device filled with the second hydrogen generating material in the furnace and connect it to the gas supply pipeline with a humidification function. Set the furnace temperature to 800°C, introduce 2L / min dry H2 for 2h, then switch the gas to 2L / min dry hydrogen-nitrogen mixed gas (4% H2) and cool the furnace to room temperature. Take out the first hydrogen generating material or the second hydrogen generating material and weigh it to obtain its initial mass;
[0065] 2. Reinstall the first hydrogen generating material or the second hydrogen generating material taken out into the furnace, and raise the furnace temperature to 800° C. in an atmosphere of 2 L / min dry hydrogen-nitrogen mixed gas (4% H2);
[0066] 3. The gas is switched to 2 L / min N2 (20% humidification) for 2 hours to force oxidation of the first hydrogen generating material or the second hydrogen generating material;
[0067] 4. Switch the gas to 2 L / min dry H2 for 2 h to reduce the first hydrogen generating material or the second hydrogen generating material;
[0068] 5. Repeat steps 3 and 4 20 times in sequence, then switch the gas to 2 L / min dry hydrogen-ammonia mixture (4% H2), cool the furnace to room temperature, take out the first hydrogen generating material or the second hydrogen generating material and weigh it to obtain its final mass.
[0069] The test results show that after the device of Example 1-2 repeated step 3 and step 4 20 times (ie, after 20 times of cutting off and restoring the reducing fluid supply), the mass losses of the first hydrogen generating material and the second hydrogen generating material were both ≤1%.
[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit the protection scope of the utility model. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.
Claims
1. An electrochemical device, characterized in that: It includes an electrochemical stack and a first hydrogen generating device, the electrochemical stack has a first reaction zone inlet, a first reaction zone and a first reaction zone outlet, the first reaction zone inlet and the first reaction zone outlet are respectively connected to the first reaction zone, the first reaction zone inlet of the electrochemical stack is connected to the outlet of the first hydrogen generating device, the inlet of the first hydrogen generating device is used to receive a reducing fluid and / or water vapor, the first hydrogen generating device is filled with a first hydrogen generating material, and the material of the first hydrogen generating material is a reducing metal or a reducing alloy.
2. The electrochemical device according to claim 1, characterized in that: The first hydrogen generating material has a porous structure, and the porosity of the first hydrogen generating material is 10-300 ppi.
3. The electrochemical device according to claim 1, characterized in that: The thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the first hydrogen generating material in the first hydrogen generating device is P1, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the first reaction zone is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the first hydrogen generating device is P3, and P3>P1.
4. The electrochemical device according to claim 3, characterized in that: When the inlet of the first hydrogen generating device does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack is P4, and P4>P2.
5. The electrochemical device according to claim 1, characterized in that: The electrochemical stack is a solid oxide fuel cell. The electrochemical device further comprises a reformer. The outlet of the reformer, the first hydrogen generating device and the inlet of the first reaction zone of the electrochemical stack are connected in sequence.
6. The electrochemical device according to claim 1, characterized in that: The electrochemical device is a solid oxide electrolysis cell, and the electrochemical device further comprises a mixer, wherein an outlet of the mixer, a first hydrogen generating device and an inlet of a first reaction zone of the electrochemical stack are connected in sequence.
7. The electrochemical device according to claim 1, characterized in that: The outlet of the first reaction zone of the electrochemical stack is connected to a second hydrogen generating device, and a second hydrogen generating material is arranged in the second hydrogen generating device. The material of the second hydrogen generating material is a reducing metal or a reducing alloy.
8. The electrochemical device according to claim 7, characterized in that: The second hydrogen generating material has a porous structure, and the porosity of the second hydrogen generating material is 10-300 ppi.
9. The electrochemical device according to claim 7, characterized in that: The electrochemical stack is a solid oxide fuel cell, and the electrochemical device further comprises a burner. The outlet of the first reaction zone of the electrochemical stack, the second hydrogen generating device, and the inlet of the burner are connected in sequence.
10. The electrochemical device according to claim 7, characterized in that: The thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the second hydrogen generating material in the second hydrogen generating device is P5, and the thermodynamic equilibrium hydrogen partial pressure of the oxidation reaction of the catalyst in the first reaction zone is P2; when the electrochemical device operates normally, the hydrogen partial pressure in the second hydrogen generating device is P6, and P6>P5; when the inlet of the first hydrogen generating device does not receive the reducing fluid, the hydrogen partial pressure in the first reaction zone of the electrochemical stack is P4, and P4>P2.