An integrated heat exchange and heating device for high-temperature electrolysis hydrogen production systems and its application

Abstract

This invention discloses an integrated heat exchange and heating device and its application in a high-temperature electrolytic hydrogen production system. Belonging to the field of high-temperature electrolytic hydrogen production, it aims to solve the problem in existing technologies where the heating device and connecting pipes are subject to different temperatures and thermal expansion mismatches, leading to significant thermal stress between the equipment and connecting pipes, and consequently, device failure. The integrated heat exchange and heating device includes a cylinder, an outer insulation body, a heat exchange end plate, heat exchange tubes, a first baffle plate, a porous baffle plate, a third baffle plate, heating tubes, an explosion-proof junction box, a cold-side inlet pipe, a cold-side outlet pipe, a hot-side inlet pipe, and a hot-side outlet pipe. There are multiple heat exchange tubes and heating tubes, and at least two first baffle plates, porous baffle plates, and third baffle plates. This application features small size, high thermal efficiency, and integrated heat exchange and heating, which facilitates compact integration and stable operation.

Description

Technical Field

[0001] This invention relates to the field of high-temperature electrolytic hydrogen production, particularly to the field of integrated heat exchange and heating systems, specifically an integrated heat exchange and heating device and its application in high-temperature electrolytic hydrogen production systems. More specifically, this application provides a method and apparatus for reducing thermal stress in heat exchange and heating devices used in high-temperature electrolytic hydrogen production systems. Background Technology

[0002] High-temperature electrolysis for hydrogen production is a method that produces hydrogen gas by electrolyzing water under high-temperature conditions. The reaction equation is: 2H₂O(g) → 2H₂(g) + O₂(g). This reaction requires high-temperature conditions, typically above 700℃. High temperatures increase the energy of water molecules dissociating into hydrogen and oxygen ions, while high pressure promotes the reaction towards the production of hydrogen and oxygen gas.

[0003] To effectively reduce heat loss, heat exchange devices are typically used for heat recovery in high-temperature hydrogen production systems. Most existing high-temperature hydrogen production systems employ a combination of heat exchangers and electric heaters to heat the feed gas. In this structure, the feed gas flows sequentially through the heat exchanger, pipelines, and electric heater before entering the high-temperature electrolytic reactor for the electrolysis reaction.

[0004] In existing high-temperature hydrogen production systems, heat exchangers and heating devices need to be located in high-temperature environments (600-800℃), and the devices are rigidly connected by pipes. To improve the integration and efficiency of hydrogen production units, a compact layout of equipment is often required. When operating in high-temperature environments, the equipment and connecting pipes are affected by different temperatures and thermal expansion mismatches, which often leads to significant thermal stress between the equipment and connecting pipes, resulting in unit failure.

[0005] How to solve this problem has become a research challenge for researchers. Summary of the Invention

[0006] Thermal stress, also known as variable-temperature stress, refers to the stress generated when an object cannot expand and contract freely due to external constraints and internal constraints between its parts when the temperature changes. The problem of significant thermal stress between heating devices and connecting pipes, and between heat exchange devices and connecting pipes, often caused by different temperatures and thermal expansion mismatches, leading to device failure, is addressed by typically selecting connecting pipes with better thermal expansion matching performance or reducing the temperature variation range. The former solution places higher demands on the materials of the connecting pipes, significantly increasing equipment costs and requiring the discovery of materials with specific performance characteristics. The latter solution inevitably sacrifices integration and efficiency. How to effectively solve these problems has long been a challenge for researchers.

[0007] One of the objectives of this invention is to provide an integrated heat exchange and heating device for a high-temperature electrolysis hydrogen production system, comprising a cylinder, an outer shell insulation body, a heat exchange end plate, a heat exchange tube, a first baffle plate, a porous baffle plate, a third baffle plate, a heating tube, an explosion-proof junction box, a cold-side inlet pipe, a cold-side outlet pipe, a hot-side inlet pipe, and a hot-side outlet pipe, wherein there are a plurality of heat exchange tubes and heating tubes, and at least two first baffle plates, porous baffle plates, and third baffle plates;

[0008] The cylinder includes a first air inlet, a first heat exchange section, a second variable diameter connecting section, and a third heating section. The first air inlet is a sphere with one end open. The first heat exchange section is a tube with a constant diameter. The second variable diameter connecting section is a tube with a variable diameter and is frustum-shaped. The third heating section is a cylinder with one end open and is designed with a constant diameter.

[0009] The opening end of the first air inlet, the first heat exchange section, the second diameter changing connecting section, and the opening end of the third heating section are sequentially connected to form a cylinder; the inner diameter of the first heat exchange section is larger than the inner diameter of the third heating section, and the central axis of the first heat exchange section, the central axis of the second diameter changing connecting section, and the central axis of the third heating section coincide with each other.

[0010] The heat exchange end plates are a set, and the heat exchange end plates are arranged in parallel within the first heat exchange section. The inner wall of the first heat exchange section and the heat exchange end plates form a first heat exchange shell side.

[0011] A first heat exchange inlet space is formed between the first inlet end and the adjacent heat exchange end plate, and a first heat exchange outlet space is formed between the inner wall of the second variable diameter connecting section and the adjacent heat exchange end plate. The heat exchange tube passes through the heat exchange end plate in sequence, and the gas in the first heat exchange inlet space can enter the first heat exchange outlet space through the heat exchange tube.

[0012] There are at least two first baffles, which are staggered in the first heat exchange shell. The heat exchange tubes pass through the first baffles in sequence, and the gas in the first heat exchange shell can flow in an S-shape under the action of the first baffles.

[0013] The porous baffles are staggered in the first heat exchange outlet space, and the porous baffles can fully mix the gas entering the first heat exchange outlet space and improve its turbulent kinetic energy.

[0014] The heating tube includes a heating working section for heating the gas and a heating connecting section for connecting to the heating working section. The heating working section is L-shaped. One end of the heating connecting section is located in the third heating section, and the other end of the heating connecting section passes through the tube wall of the cylinder and is connected to the heating connecting section. The heating connecting section is connected to the explosion-proof junction box.

[0015] The third heating section forms a third heating space, and the third baffles are staggered in the third heating space. The heating tube passes through the third baffles, and the gas in the third heating space can flow in an S-shape under the action of the third baffles.

[0016] The cold-side inlet pipe is connected to the first heat exchange inlet space, and the gas to be heated enters the heat exchange pipe through the first heat exchange inlet space and then enters the first heat exchange outlet space. The cold-side outlet pipe is connected to the third heating space, and the gas in the first heat exchange outlet space is mixed by the porous baffle and then enters the third heating space for heating and is discharged through the cold-side outlet pipe.

[0017] The hot-side inlet pipe is connected to the first heat exchange shell, and the gas that undergoes electrolysis reaction in the electrolytic reactor can enter the first heat exchange shell through the hot-side inlet pipe. The hot-side outlet pipe is connected to the first heat exchange shell, and the gas in the first heat exchange shell can be discharged through the hot-side outlet pipe after heat exchange.

[0018] The outer insulation body is installed on the outer wall of the cylinder.

[0019] One end of the heating connection section passes through the pipe wall of the second reducing connection section and is connected to the heating connection section.

[0020] The first air inlet, the first heat exchange section, the second diameter-changing connecting section and the third heating section are integrally formed.

[0021] The opening end of the first air inlet, the first heat exchange section, the second diameter-changing connecting section, and the opening end of the third heating section are sequentially connected by welding to form a whole.

[0022] The outer insulation body is made of insulation material, which is wrapped around the outer wall of the cylinder.

[0023] There is a gap between the outer insulation body and the cylinder.

[0024] The insulation material is made of one or more of glass fiber and ceramic fiber.

[0025] The thermal insulation material is a mixture of aluminum oxide and silicon oxide.

[0026] The thermal insulation material is composed of alumina and silicon dioxide mixed in a mass ratio of 1:0.2 to 5.

[0027] The thermal insulation material is made of alumina and silicon dioxide mixed in a 1:1 mass ratio.

[0028] The heat exchange tube is made of 310S stainless steel.

[0029] The thickness of the outer shell insulation of the first heat exchange section is 100mm, and the thickness of the outer shell insulation of the third heating section is 300mm.

[0030] The length of the second variable diameter connecting section should meet the installation requirements of the perforated baffle and heating tube.

[0031] The first air inlet is hemispherical, the first heat exchange section is cylindrical, and the inner radius of the first air inlet is the same as the inner radius of the first heat exchange section.

[0032] The third heating section is a cylindrical body with one end open;

[0033] The inner radius of the large end of the second variable diameter connecting section is the same as the inner radius of the first heat exchange section, and the inner radius of the small end of the second variable diameter connecting section is the same as the inner radius of the third heating section.

[0034] The first air inlet, the first heat exchange section, the second variable diameter connecting section, and the third heating section are all made of the same material.

[0035] The cylinder is made of one or more of Incoloy 800 alloy and Incoloy 800H alloy.

[0036] The preparation process of the heating working section is as follows:

[0037] Based on a seamless metal tube, an electric heating wire is filled inside the seamless metal tube, and magnesium oxide powder is filled into the gaps inside the seamless metal tube. Finally, the heating working section is formed by shrinking the tube.

[0038] The preparation process of the heating connection section is as follows:

[0039] It is made by filling the gaps in a seamless metal tube with magnesium oxide powder and finally sealing it with epoxy resin.

[0040] The heating working section and the heating connecting section are made of the same seamless metal tube, and the heating working section and the heating connecting section are connected in sequence to form a whole.

[0041] The seamless metal tube is made of one or more of Incoloy 800 alloy and Incoloy 800H alloy.

[0042] The second objective of this application is to address the problem of significant thermal stress often occurring between heating devices and connecting pipes, and between heat exchange devices and connecting pipes in high-temperature hydrogen production systems. This invention provides a method to reduce thermal stress between heat exchange and heating devices in high-temperature electrolytic hydrogen production systems. The method involves replacing the existing connecting pipes between the heating device and the heat exchange device with a second variable-diameter connecting section. The larger end of the second variable-diameter connecting section is directly connected to the first heat exchange section, and the smaller end of the second variable-diameter connecting section is directly connected to the third heating section. The central axes of the first heat exchange section, the second variable-diameter connecting section, and the third heating section coincide with each other.

[0043] The second variable diameter connecting section is affected by temperature changes, which can cause the first heat exchange section and the third heating section on both sides to shrink or expand synchronously along the central axis of the first heat exchange section to reduce thermal stress.

[0044] An integrated cylindrical body is used as the main structure for heat exchange and heating;

[0045] The cylinder includes a first air inlet, a first heat exchange section, a second variable diameter connecting section, and a third heating section. The first air inlet is a sphere with one end open. The first heat exchange section is a tube with a constant diameter. The second variable diameter connecting section is a tube with a variable diameter and is frustum-shaped. The third heating section is a cylinder with one end open and is designed with a constant diameter.

[0046] The opening ends of the first air inlet, the first heat exchange section, the second diameter-changing connecting section, and the third heating section are sequentially connected to form a cylindrical body; the inner diameter of the first heat exchange section is larger than the inner diameter of the third heating section, and the central axes of the first heat exchange section, the second diameter-changing connecting section, and the third heating section coincide with each other.

[0047] An outer heat insulation body is provided on the outer wall of the cylinder, and there is a gap between the outer heat insulation body and the cylinder, and the cylinder can contract or expand relative to the outer heat insulation body.

[0048] The second variable diameter connecting section is affected by temperature changes, which can cause the first heat exchange section and the third heating section on both sides to shrink or expand synchronously along the central axis of the first heat exchange section to reduce thermal stress.

[0049] The third objective of this application is to provide the application of the aforementioned integrated heat exchange and heating device in a high-temperature electrolysis hydrogen production system.

[0050] This integrated heat exchange and heating device is used in a high-temperature electrolysis hydrogen production system. Attached Figure Description

[0051] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0052] Figure 1 This is a schematic diagram of the integrated heat exchange and heating device used in the high-temperature electrolysis hydrogen production system of this application.

[0053] Figure 2 This is a simplified structural diagram of the heat exchange device and the heating device when they are independent in the prior art.

[0054] The markings in the diagram are: 1. Cold side outlet pipe, 2. Hot side inlet pipe, 3. Outer shell insulation, 4. Cylinder, 5. Heat exchange end plate, 6. Cold side inlet pipe, 7. Hot side outlet pipe, 8. Heat exchange tube, 9. First baffle plate, 10. Perforated baffle plate, 11. Heating tube, 12. Explosion-proof junction box, 20. Heat exchange device, 21. Connecting pipe, 22. Heating device. Detailed Implementation

[0055] All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive features and / or steps.

[0056] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0057] Example 1

[0058] (I) Description of the device structure.

[0059] This embodiment provides an integrated heat exchange and heating device for a high-temperature electrolysis hydrogen production system, comprising a cylinder, an outer insulation body, a heat exchange end plate, heat exchange tubes, a first baffle plate, a porous baffle plate, a third baffle plate, heating tubes, an explosion-proof junction box, a cold-side inlet pipe, a cold-side outlet pipe, a hot-side inlet pipe, and a hot-side outlet pipe. The heat exchange tubes and heating tubes are provided in multiples, and the first baffle plate, the porous baffle plate, and the third baffle plate are each provided in at least twos.

[0060] The cylindrical body is used to collect gas, sealing it inside the equipment for heat exchange and heating. In this embodiment, the cylindrical body includes a first inlet end, a first heat exchange section, a second variable-diameter connecting section, and a third heating section. The first inlet end is a sphere open at one end; the first heat exchange section is a tube of constant diameter; the second variable-diameter connecting section is a tube of variable diameter and is frustum-shaped; the third heating section is a cylindrical body open at one end and uses a constant-diameter design. In a specific example, the first inlet end is hemispherical, the first heat exchange section is cylindrical, and the inner radius of the first inlet end is the same as that of the first heat exchange section; the third heating section is a cylindrical body open at one end; the inner radius of the larger end of the second variable-diameter connecting section is the same as that of the first heat exchange section, and the inner radius of the smaller end of the second variable-diameter connecting section is the same as that of the third heating section.

[0061] The open end of the first air inlet, the first heat exchange section, the second diameter-changing connecting section, and the open end of the third heating section are sequentially connected to form a cylindrical body. The inner diameter of the first heat exchange section is larger than that of the third heating section, and the central axes of the first heat exchange section, the second diameter-changing connecting section, and the third heating section coincide. Further, the first air inlet, the first heat exchange section, the second diameter-changing connecting section, and the third heating section are made of the same material. In a specific example, the cylindrical body material can be Incoloy 800 alloy or Incoloy 800H alloy. Further, the first air inlet, the first heat exchange section, the second diameter-changing connecting section, and the third heating section are integrally formed; preferably, the open end of the first air inlet, the first heat exchange section, the second diameter-changing connecting section, and the open end of the third heating section are sequentially connected by welding.

[0062] The heat exchange end plates are arranged in a set, parallel to each other within the first heat exchange section. The inner wall of the first heat exchange section and the two heat exchange end plates form the first heat exchange shell side. As shown in the figure, a first heat exchange inlet space is formed between the first inlet end and the adjacent heat exchange end plate, and a first heat exchange outlet space is formed between the inner wall of the second variable diameter connecting section and the adjacent heat exchange end plate. The heat exchange tubes pass through the heat exchange end plates sequentially, and the gas in the first heat exchange inlet space can enter the first heat exchange outlet space through the heat exchange tubes. There are at least two first baffles, which are staggered within the first heat exchange shell side. The heat exchange tubes pass through the first baffles sequentially, and the gas in the first heat exchange shell side can flow in an S-shape under the action of the first baffles. In this embodiment, the heat exchange part of the integrated heat exchange and heating device is divided into a tube side and a shell side; wherein, the tube side carries the cold fluid, and the shell side carries the hot fluid. The heat exchange tubes are made of multiple seamless steel tubes. To ensure good high-temperature reliability of the device, 310S stainless steel is preferred for the heat exchange tubes. The length, number, inner diameter, and wall thickness of the heat exchange tubes are calculated and selected based on the gas heat exchange capacity, gas flow rate, and gas physical properties under specific operating conditions. The first baffle plate is used to fix and support the heat exchange tubes, so that the heat exchange tubes can be reliably placed inside the equipment.

[0063] Porous baffles are staggered within the first heat exchange outlet space, enabling thorough mixing of the gas entering this space and enhancing its turbulent kinetic energy. In this application, the first heat exchange section is connected to the third heating section via a second diameter-reducing connecting section. The pipe diameter decreases from the heat exchange section to the heating section, and porous baffles are installed within the first heat exchange outlet space. In this structure, the porous baffles are used to thoroughly mix the tube-side fluid after heat exchange, while simultaneously enhancing its turbulent kinetic energy and improving the heating efficiency of the downstream section.

[0064] In this embodiment, the heating tube includes a heating working section for heating the gas and a heating connecting section for connecting to the heating working section. The heating working section is L-shaped. One end of the heating connecting section is disposed within the third heating section, and the other end passes through the tube wall of the cylinder and connects to the heating connecting section. The heating connecting section is connected to an explosion-proof junction box. The interior of the third heating section forms a third heating space, within which third baffles are staggered. The heating tube passes through the third baffles, and the gas within the third heating space can flow in an S-shape under the action of the third baffles. Furthermore, one end of the heating connecting section passes through the tube wall of the second reducing connecting section and connects to the heating connecting section.

[0065] The heating tube is formed by inserting a heating wire into a seamless metal tube, filling the gaps with magnesium oxide powder, which has good thermal conductivity and insulation, and then shrinking the tube. Because high-temperature magnesium oxide powder exposed to air readily absorbs moisture and carbon dioxide, gradually becoming basic magnesium carbonate and losing its insulating properties, it must be externally sealed. In this embodiment, epoxy resin is used for sealing; however, since epoxy resin is not heat-resistant, the heating tube outside the cylinder in this embodiment is a non-heating section used for heat dissipation and cooling. The length and number of heating tubes are selected according to the required electric heating power under actual working conditions. In a specific example, the seamless metal tube used for the heating tube can be Incoloy 800 or Incoloy 800H alloy. The cold end of the heating tube extends from the connection between the heat exchange section and the heating section; the temperature is lower at this point, which is beneficial for heat dissipation of the explosion-proof junction box and reduces the overall length of the equipment. The explosion-proof junction box contains wires for connecting the electrical wires; during use, the power supply is provided to the heating tube through the wires connected to the explosion-proof junction box. The explosion-proof junction box can be designed according to environmental requirements to meet different explosion-proof ratings.

[0066] The cold-side inlet pipe is connected to the first heat exchange inlet space, and the gas to be heated enters the heat exchange tube through the first heat exchange inlet space for heat exchange, and then enters the first heat exchange outlet space. At the same time, the cold-side outlet pipe is connected to the third heating space, and the gas in the first heat exchange outlet space is mixed by the porous baffle plate, can enter the third heating space for heating, and then be discharged through the cold-side outlet pipe.

[0067] The hot-side inlet pipe is connected to the first heat exchange shell side, and the gas that has undergone electrolysis in the electrolytic reactor can enter the first heat exchange shell side through the hot-side inlet pipe. The hot-side outlet pipe is connected to the first heat exchange shell side, and the gas in the first heat exchange shell side can be discharged through the hot-side outlet pipe after heat exchange.

[0068] In this embodiment, the outer insulation body is disposed on the outer wall of the cylinder. The outer insulation body is used for overall equipment outer wall insulation, reducing heat loss. A gap exists between the outer insulation body and the cylinder. In a specific example, the outer insulation body is composed of insulation material, which is wound around the outer wall of the cylinder. The insulation material can be glass fiber, ceramic fiber, or other similar materials. Furthermore, the length of the second variable diameter connecting section is sufficient to meet the installation requirements of the porous baffle and heating tube.

[0069] (ii) Here, the specific sample preparation process is explained as follows.

[0070] The design and operation steps of the integrated heat exchange and heating device for the high-temperature hydrogen production system are as follows: To raise the temperature of a mixture of hydrogen (10%) and water vapor (90%) (i.e., the volume ratio of hydrogen to water vapor in the mixture is 10:90) from 150°C to 700°C.

[0071] 1. Based on the external piping dimensions and gas flow rate, determine the dimensions of the four gas inlet and outlet pipes (i.e., cold-side inlet pipe, cold-side outlet pipe, hot-side inlet pipe, and hot-side outlet pipe). The gas inlet and outlet pipes of this equipment are butt-welded to the external piping. In a specific example, the gas inlet and outlet pipes are all selected with an outer diameter of 60mm and a wall thickness of 3mm.

[0072] 2. Based on the operating conditions such as the flow rate and pressure of the hydrogen and water vapor mixture, the diameter, wall thickness, effective length, and number of heat exchange tubes are calculated. Simultaneously, the length, number, and power of the heating tubes, as well as the cylinder diameter, are calculated. In one example, the flow rate of the hydrogen and water vapor mixture is 200 L / min, and the inlet pressure is 45 Pa. The heat exchange tubes have a diameter of 20 mm, a wall thickness of 1 mm, an effective length of 1000 mm, and a quantity of 135 tubes. The heating tubes have a length of 1000 mm, a quantity of 6 tubes, are bent and folded, and have a power of 1500 W. The length of the first heat exchange section in the cylinder is consistent with the effective heat exchange length, with a diameter of 300 mm and a wall thickness of 3 mm. The second diameter-changing connecting section and the third heating section in the cylinder change from a diameter of 300 mm to 100 mm and a length of 500 mm (of which, the length of the second diameter-changing connecting section is 100 mm, and the length of the third heating section is 400 mm).

[0073] 3. The various parts are integrated together by welding, and insulation material is wrapped around the outermost layer of the cylinder to form an outer insulation body. In one embodiment, the thickness of the insulation material on the outer side of the first heat exchange section of the cylinder is 100 mm, and the thickness of the insulation material on the outer side of the third heating section of the cylinder is 300 mm. The insulation material is selected as 50 wt% Al2O3-50 wt% SiO2.

[0074] 4. After the equipment is completed, connect the wires to the explosion-proof junction box.

[0075] 5. A mixture of hydrogen and water vapor at 150°C enters the device through the cold-side inlet pipe and flows through the inner side of the heat exchange tubes (i.e., the tube side). The mixture is heated to 450-500°C within the heat exchange tubes. It then flows into the second variable-diameter connecting section, where the turbulence coefficient increases after passing through the porous baffles, and the temperature mixing becomes more uniform. Next, it flows into the third heating section, where the heating tubes reheat the gas. The heated gas then exits through the cold-side outlet pipe at a temperature of 700-750°C. After passing through the electrolytic reactor and undergoing electrolysis, the gas temperature remains at 700-750°C. It then flows back into the shell side of the heat exchange section through the hot-side inlet pipe, further heating the gas flowing through the heat exchange tubes. The heated gas then exits through the hot-side outlet pipe at a temperature of 300-350°C.

[0076] (III) Experimental comparison.

[0077] 1. When the heat exchange device and the heating device are independent, their simplified structural diagram is as follows: Figure 2 As shown. Figure 2 In the diagram, 20 is a heat exchanger, 21 is a connecting pipe, and 22 is a heating device. Separate heat exchangers and heating devices require independent arrangement, occupying integrated space and increasing the overall heat dissipation area, which is detrimental to improving the thermal efficiency of the electrolytic high-temperature hydrogen production system.

[0078] Under the premise that the heat exchanger and heating device are the same, a comparison is made between the existing independent solutions and the integrated heat exchanger and heating solution of this application:

[0079] (1) Before the improvement (when the heat exchange device and the heating device are independent), the separated heat dissipation area is 4.9028m². 2 The thermal efficiency during separation is 67.49%;

[0080] (2) After improvement (when using the integrated heat exchange and heating of this application), the integrated heat dissipation area is 3.3429m². 2 The integrated thermal efficiency is 71.64%.

[0081] (3) Compared with the original design (when the heat exchanger and heating device were independent), the heat dissipation area of ​​the improved integrated design was reduced by 1.5599 m². 2 .

[0082] 2. When the heat exchanger and heating device are independent, the temperature of the cold-side inlet pipe of the heat exchanger is approximately room temperature -200℃, the temperature of the cold-side outlet pipe is approximately 500-600℃, the temperature of the hot-side inlet pipe is approximately 700-800℃, and the temperature of the hot-side outlet pipe is approximately 300-400℃. The temperature of the connecting pipe between the cold-side outlet of the heat exchanger and the inlet of the heating device is approximately 500-600℃. Due to the uncoordinated thermal expansion and deformation of the connecting pipe, its stress can reach 100-200MPa or more, far exceeding the allowable stress of the pipe material at this temperature. In addition, the pipe openings at the cold-side outlet of the heat exchanger and the inlet of the heating device are also prone to stress exceeding 100MPa due to the thermal expansion of the connecting pipes, which can lead to pipe breakage.

[0083] Unlike existing technologies, to reduce the impact of thermal stress on the equipment and high-temperature connecting pipes, this application eliminates the connecting pipe at that location and uses a second variable-diameter connecting section to connect the first heat exchange section and the third heating section. The overall structure is also redesigned to achieve integrated heat exchange and heating. In this structure, the second variable-diameter connecting section between the first heat exchange section and the third heating section can freely move its left and right parts, thus reducing its thermal stress to a few MPa or lower.

[0084] Theoretical analysis and experimental results show that the integrated design of this application can effectively improve the large temperature difference caused by uneven temperature distribution in high-temperature hot zones and the thermal stress caused by the incoordination of thermal expansion between components. Furthermore, because the equipment in this application is axially arranged, the internal thermal expansion of the equipment proceeds freely along the axial direction, resulting in lower thermal stress.

[0085] This application adopts an integrated design, tightly integrating all components together, and directly connecting the first heat exchange section and the third heating section via a second variable-diameter connecting section. This structure further improves system efficiency. Simultaneously, this application effectively reduces internal thermal stress, ensures reliable connections between equipment and pipelines, and effectively extends the equipment's continuous operating time and work cycle.

[0086] In summary, the integrated device of this application can meet the requirements of efficient heat exchange and heating of raw gas in high-temperature electrolysis hydrogen production systems. The device is characterized by small size, high thermal efficiency, and integrated heat exchange and heating, which is conducive to the overall high efficiency, compact integration, and stable operation.

[0087] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A heat exchange and heating integrated device for a high-temperature electrolytic hydrogen production system, characterized in that, The cylinder, the shell heat preservation body, the heat exchange end plate, the heat exchange pipe, the first baffle, the porous baffle, the third baffle, the heating pipe, the explosion-proof junction box, the cold side inlet pipe, the cold side outlet pipe, the hot side inlet pipe and the hot side outlet pipe are arranged in the cylinder. The cylinder comprises a first gas inlet end, a first heat exchange section, a second variable-diameter connecting section and a third heating section. The first gas inlet end, the first heat exchange section, the second variable-diameter connecting section and the third heating section are connected in sequence and form the cylinder. The heat exchange end plate is arranged in the first heat exchange section. The first gas inlet end and the adjacent heat exchange end plate form a first heat exchange gas inlet space. The first baffle is arranged in the first heat exchange shell side. The porous baffle is arranged in the first heat exchange outlet space. The heating pipe comprises a heating working section and a heating connecting section. The third heating section forms a third heating space. The cold side inlet pipe is connected to the first heat exchange gas inlet space. The cold side outlet pipe is connected to the third heating space. The hot side inlet pipe is connected to the first heat exchange gas inlet space. The hot side outlet pipe is connected to the third heating space. The hot side inlet pipe is communicated with the first heat exchange shell passage, and the gas generated by electrolysis reaction in the electrolysis stack can enter the first heat exchange shell passage through the hot side inlet pipe; the hot side outlet pipe is communicated with the first heat exchange shell passage, and the gas in the first heat exchange shell passage can be discharged through the hot side outlet pipe after heat exchange; The outer shell heat insulating body is arranged on the outer wall of the cylinder body.

2. The heat exchange and heating integrated device according to claim 1, characterized in that, The first gas inlet end is hemispherical, the first heat exchange section is circular tubular, and the inner diameter radius of the first gas inlet end is the same as that of the first heat exchange section; The third heating section is a circular cylinder with one end open; The inner diameter radius of the large end of the second variable diameter connecting section is the same as that of the first heat exchange section, and the inner diameter radius of the small end of the second variable diameter connecting section is the same as that of the third heating section.

3. The heat exchange and heating integrated device according to claim 1 or 2, characterized by The first gas inlet end, the first heat exchange section, the second variable diameter connecting section and the third heating section are made of the same material.

4. The heat exchange and heating integrated device according to claim 3, characterized in that, The preparation process of the heating working section is as follows: Based on a seamless metal pipe, the heating wire is filled in the seamless metal pipe, and the magnesium oxide powder is filled in the gap in the seamless metal pipe, and finally the heating working section is formed by pipe shrinking; The preparation process of the heating connecting section is as follows: Based on a seamless metal pipe, the magnesium oxide powder is filled in the gap in the seamless metal pipe, and finally the heating connecting section is sealed by using epoxy resin glue; The heating working section and the heating connecting section adopt the same seamless metal pipe, and the heating working section and the heating connecting section are sequentially connected to be integrated.

5. A method for reducing thermal stress between heat exchange heating devices in a high-temperature electrolytic hydrogen production system, characterized in that, The second variable diameter connecting section is adopted to replace the connecting pipeline between the existing heating device and the heat exchange device, the large end of the second variable diameter connecting section is directly connected with the first heat exchange section, the small end of the second variable diameter connecting section is directly connected with the third heating section, and the central axes of the first heat exchange section, the second variable diameter connecting section and the third heating section coincide with each other; The second variable diameter connecting section can drive the first heat exchange section and the third heating section on both sides thereof to synchronously contract or expand along the central axis direction of the first heat exchange section to reduce thermal stress under the influence of temperature change.

6. The method of claim 5, wherein, An integrated cylinder body is adopted as the main structure of heat exchange and heating; The cylinder body includes a first gas inlet end, a first heat exchange section, a second variable diameter connecting section and a third heating section, the first gas inlet end is a spherical body with one end open, the first heat exchange section is a constant-diameter pipe body, the second variable diameter connecting section is a variable-diameter pipe body and is in the shape of a circular truncated cone, and the third heating section is a cylinder body with one end open, and the third heating section adopts constant-diameter design; The open end of the first gas inlet end, the first heat exchange section, the second variable diameter connecting section and the open end of the third heating section are sequentially connected to be integrated and constitute the cylinder body, the inner diameter of the first heat exchange section is greater than that of the third heating section, and the central axes of the first heat exchange section, the second variable diameter connecting section and the third heating section coincide with each other; An outer shell heat insulating body is arranged on the outer wall of the cylinder body, and there is a gap between the outer shell heat insulating body and the cylinder body, and the cylinder body can contract or expand relative to the outer shell heat insulating body; The second variable diameter connecting section can drive the first heat exchange section and the third heating section on both sides thereof to synchronously contract or expand along the central axis direction of the first heat exchange section to reduce thermal stress under the influence of temperature change.

7. Use of the heat exchange and heating integrated device according to any one of the preceding claims 1-4 in a high-temperature electrolysis hydrogen production system.

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