An internal heating type palladium membrane purifier

Abstract

The application discloses an inner heat type palladium membrane purifier, which comprises an outer shell and an inner shell, a heat preservation layer is filled between the outer shell and the inner shell, the inner shell comprises a diffusion chamber and a preheating chamber, the palladium membrane purifier further comprises a heating pipe which is inserted into the diffusion chamber, the heating pipe is internally provided with an electric heating element, a palladium alloy pipe is spirally wound outside the heating pipe, one end of the diffusion chamber is provided with an end face flange, the end face flange is provided with a pure hydrogen interface and a tail gas interface, the pure hydrogen interface is communicated with the diffusion chamber and the outside of the outer shell, the tail gas interface is connected with one end of the palladium alloy pipe, the other end of the palladium alloy pipe is connected with a raw material gas preheating coil pipe, the other end of the preheating coil pipe is extended out of the outer shell and is provided with a raw material hydrogen interface, and the palladium membrane purifier further comprises a temperature measuring sleeve pipe. The hydrogen purifier disclosed by the application has the advantages of compact layout, small device volume, few welding points of a palladium membrane assembly, reliable process, long service life, uniform heating temperature of the device, small heat loss, high purification and separation efficiency of hydrogen, and large gas processing capacity per unit volume.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen purification technology, specifically relating to an internally heated palladium membrane purifier. Background Technology

[0002] In recent years, with the rapid development of hydrogen-oxygen fuel cells, optoelectronics, semiconductors and nuclear energy industries, palladium and palladium alloy membranes have been widely used in hydrogen (and isotope) separation and purification devices, dehydrogenation and hydrogenation reaction devices due to their unique hydrogen permeation selectivity, good thermal stability and catalytic performance.

[0003] Palladium membrane purifiers typically consist of a palladium membrane module, a diffusion chamber shell, interface pipes, and an auxiliary heater. The palladium membrane module is the core component, operating at 300-500℃ and a relatively high pressure differential. Given a fixed palladium membrane composition, thickness, and operating conditions, the purifier's structural form and parameters significantly impact hydrogen purification and separation performance. Current palladium membrane purifiers use a core component where multiple palladium membrane tubes are bundled and welded at one end to a metal flange to increase the hydrogen permeation area. This results in numerous weld points and relatively poor reliability. Furthermore, this type of purifier requires an external heating device to heat the palladium membrane module, leading to a larger overall purifier size, slightly less uniform temperature distribution, and lower thermal efficiency.

[0004] Therefore, an internally heated palladium membrane purifier is needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing an internally heated palladium membrane purifier. This internally heated palladium membrane purifier preheats the raw material gas in a preheating chamber, allowing it to quickly reach the purification reaction temperature upon entering the diffusion chamber. This facilitates faster diffusion and permeation of pure hydrogen, improving hydrogen permeation efficiency. The raw material gas preheating coil in the preheating chamber increases the residence time of the raw material gas, ensuring more thorough preheating. Furthermore, the preheating coil is small in size and compact in structure, which is beneficial to the overall structural layout of the purifier. By incorporating a diffusion chamber with a heating tube spirally wound with palladium alloy tubing, the structure is compact with fewer welding points, reducing the overall volume of the purifier and improving process reliability and service life for high-purity hydrogen purification and separation.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an internally heated palladium membrane purifier, characterized in that the palladium membrane purifier includes an outer shell, an inner shell disposed within the outer shell, and a heat insulation layer filled between the outer shell and the inner shell. The inner shell includes a diffusion chamber and a preheating chamber. The palladium membrane purifier also includes a heating tube inserted into the diffusion chamber at one end, the heating tube having an internal electric heating element. A palladium alloy tube is spirally wound around the end of the heating tube inserted into the diffusion chamber. The end of the diffusion chamber opposite to the inserted heating tube is an end face flange. The end face flange is provided with a pure hydrogen interface and a tail gas interface extending out of the outer shell. The pure hydrogen interface connects the diffusion chamber and the outside of the outer shell. The tail gas interface is connected to one end of the palladium alloy tube. The other end of the palladium alloy tube is connected to a raw material gas preheating coil located in the preheating chamber. The other end of the preheating coil extends out of the outer shell and is provided with a raw material hydrogen interface. The palladium membrane purifier also includes a temperature measuring sleeve extending into the diffusion chamber at one end.

[0007] The aforementioned internally heated palladium membrane purifier is characterized in that the palladium alloy tube is a self-supporting dense tube.

[0008] The aforementioned internal heating palladium membrane purifier is characterized in that the palladium alloy tube is made of palladium or a palladium alloy tube, and the palladium alloy contains at least one element selected from Ag, Cu, Y, Au, Ru and Ce.

[0009] The aforementioned internal heating palladium membrane purifier is characterized in that the palladium alloy tube is made by winding a single palladium alloy tube, or by winding multiple palladium alloy tubes after butt welding, and the number of weld points of the butt-welded spiral palladium alloy tube is less than 10.

[0010] The aforementioned internally heated palladium membrane purifier is characterized in that the diameter of the palladium alloy tube is 1mm to 6mm and the wall thickness is 0.04mm to 0.1mm.

[0011] The aforementioned internal heating palladium membrane purifier is characterized in that the palladium alloy tube is spirally wound on the heating tube, wherein the diameter of the spiral coil is 50mm to 100mm, the number of spiral coil turns is 20 to 100, and the pitch is 1mm to 10mm.

[0012] The aforementioned internally heated palladium membrane purifier is characterized in that one end of the palladium alloy tube is connected to the exhaust gas interface by brazing, and the other end is connected to the raw material gas preheating coil.

[0013] The aforementioned internally heated palladium membrane purifier is characterized in that the inner shell, heating tube, temperature measuring sleeve, preheating chamber, and end flange are all made of stainless steel or heat-resistant steel.

[0014] The aforementioned internally heated palladium membrane purifier is characterized in that the inner shell is sealed to the heating tube, temperature measuring sleeve, preheating chamber and end flange by argon arc welding.

[0015] The aforementioned internally heated palladium membrane purifier is characterized in that the diameters of the pure hydrogen interface, the exhaust gas interface, and the raw material hydrogen interface are 4mm to 25mm.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. This invention preheats the raw material gas in advance by setting up a preheating chamber, so that the raw material gas quickly reaches the purification reaction temperature after entering the diffusion chamber, which is conducive to accelerating the diffusion and permeation of pure hydrogen and improving the hydrogen permeation efficiency. The raw material gas preheating coil in the preheating chamber increases the residence time of the raw material gas in the preheating chamber, making the preheating of the raw material gas more thorough. At the same time, the raw material gas preheating coil is small in size and compact in structure, which is beneficial to the overall structural layout of the purifier. By setting up a diffusion chamber and setting up a heating tube with a palladium alloy tube spirally wound in it, the structure is relatively compact with fewer welding points, reducing the overall volume of the purifier, which can improve the reliability and service life of the process and complete the purification and separation of high-purity hydrogen.

[0018] 2. In order to improve the hydrogen permeation purity of the palladium alloy tube, the present invention requires the alloy tube to be dense and defect-free. Therefore, the entire palladium alloy tube is wound. However, it is very difficult to process long, defect-free palladium alloy tubes. In addition, in order to meet the large gas throughput requirements of the purifier, multiple palladium alloy tubes are often connected in series by welding and then wound into a spiral tube in industry. However, the strength of the welded parts is low and the reliability is relatively poor. Therefore, in order to ensure the working reliability of the entire spiral palladium tube, the number of welding points is limited to no more than 10.

[0019] 3. The palladium alloy tube spirally wound onto the heating tube in this invention ensures that the gas inside the tube can be fully heated. To reduce the overall volume of the purifier, the diameter of the spiral coil should be as small as possible. However, this increases the difficulty of winding the spiral coil. A smaller diameter spiral tube can easily cause the palladium alloy tube to crack or collapse. The diameter of the spiral coil must match the diameter of the palladium alloy tube. Generally, the smaller the diameter of the palladium alloy tube, the smaller the diameter of the spiral coil. Based on the aforementioned diameter of the palladium alloy tube, the diameter range of the spiral coil is determined. The number of turns of the spiral coil is determined according to the processing capacity of the purifier. The larger the processing capacity, the more turns are needed. The pitch is determined according to the length of the heating tube, and it is necessary to ensure that the entire spiral palladium tube is uniformly wound onto the heating tube.

[0020] 4. This invention provides an internally heated high-purity hydrogen purifier with a compact layout, small device size, few solder joints in the palladium membrane module, reliable process and long service life, uniform heating temperature, low heat loss, high hydrogen purification and separation efficiency, and suitable for continuous operation.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the internal heating palladium membrane purifier of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1—Outer shell; 2—Inner shell; 3—Insulation layer;

[0025] 4—Diffusion chamber; 5—Preheating chamber; 6—Heating tube;

[0026] 7—Electric heating element; 8—Palladium alloy tube; 9—End flange;

[0027] 10—Pure hydrogen inlet; 11—Exhaust gas inlet; 12—Raw gas preheating coil;

[0028] 13—Raw material hydrogen interface; 14—Temperature measuring sleeve. Detailed Implementation

[0029] Example 1

[0030] like Figure 1 As shown, an internally heated palladium membrane purifier of this embodiment includes an outer shell 1, an inner shell 2 disposed within the outer shell 1, and a heat insulation layer 3 filling the space between the outer shell 1 and the inner shell 2. The inner shell 2 includes a diffusion chamber 4 and a preheating chamber 5. The palladium membrane purifier also includes a heating tube 6 inserted into the diffusion chamber 4 at one end, an electric heating element 7 built into the heating tube 6, and a palladium alloy tube 8 spirally wound around the end of the heating tube 6 inserted into the diffusion chamber 4. The end of the diffusion chamber 4 opposite to the end of the heating tube 6 is an end face flange 9, on which a pure hydrogen interface 10 and a tail gas interface 11 are provided extending out of the outer shell 1. The pure hydrogen interface 10 connects the diffusion chamber 4 and the outside of the outer shell 1. The tail gas interface 11 is connected to one end of the palladium alloy tube 8, and the other end of the palladium alloy tube 8 is connected to a raw material gas preheating coil 12 located in the preheating chamber 5. The other end of the preheating coil extends out of the outer shell 1 and is provided with a raw material hydrogen interface 13. The palladium membrane purifier also includes a temperature measuring sleeve 14 extending into the diffusion chamber 4 at one end.

[0031] It should be noted that by setting up an outer shell 1 and an inner shell 2 with an insulation layer 3 filling the space between them, a diffusion chamber 4 and a preheating chamber 5 are formed inside the inner shell 2. This is a key part of the palladium alloy diffusion hydrogen purification process. By setting up the preheating chamber 5 to preheat the raw material gas, the raw material gas can quickly reach the purification reaction temperature after entering the diffusion chamber 4, which is conducive to accelerating the diffusion and permeation of pure hydrogen and improving the hydrogen permeation efficiency. The raw material gas preheating coil 12 in the preheating chamber 5 increases the residence time of the raw material gas in the preheating chamber 5, making the preheating of the raw material gas more thorough. At the same time, the raw material gas preheating coil 12 is small in size and compact in structure, which is beneficial to the overall structural layout of the purifier. By setting up the diffusion chamber 4 and setting up the heating tube 6 with a palladium alloy tube 8 spirally wound in it, the structure is relatively compact with fewer welding points, reducing the overall volume of the purifier, improving the reliability and service life of the process, and enabling the purification and separation of high-purity hydrogen.

[0032] It should be noted that the outer diameter of the heating tube 6 is 60mm to 100mm, preferably 60mm, 80mm, or 100mm, and the electric heating element 7 is a coil electric heating element or a ceramic electric heating element.

[0033] It should be noted that the diameter of the temperature measuring sleeve 14 is 8mm.

[0034] In this embodiment, the palladium alloy tube 8 is a self-supporting dense tube. The use of a self-supporting dense tube is in contrast to a palladium film composite tube. For example, a palladium film composite tube can be formed by plating a layer of palladium onto porous stainless steel. While palladium film composite tubes have advantages such as low palladium usage and high hydrogen permeation rate, they also have disadvantages such as poor bonding strength, easy peeling during use, and short service life. In contrast, the self-supporting dense tube, due to its greater thickness, possesses a certain strength and can withstand the load, thus improving the stability of the device.

[0035] In this embodiment, the palladium alloy tube 8 is made of palladium or a palladium alloy, and the palladium alloy contains at least one element selected from Ag, Cu, Y, Au, Ru, and Ce. Generally, palladium tubes or palladium alloy tubes containing the above elements have good processing and shaping properties, are easy to manufacture into spiral tubes, and all have high hydrogen permeation rates.

[0036] In this embodiment, the palladium alloy tube 8 is wound from a single palladium alloy tube 8, or wound from multiple palladium alloy tubes 8 after butt welding. The number of weld points in the butt-welded spiral palladium alloy tube 8 is less than 10. To improve the hydrogen permeation purity of the palladium alloy tube 8, the alloy tube must be dense and defect-free. Therefore, it is best to use a single palladium alloy tube for winding. However, processing long, defect-free palladium alloy tubes is very difficult. In addition, to meet the large gas throughput requirements of the purifier, multiple palladium alloy tubes are often connected in series by welding before being wound into a spiral tube in industry. However, the strength of the welded joints is low, and the reliability is relatively poor. Therefore, to ensure the working reliability of the entire spiral palladium tube, the number of weld points is limited to no more than 10.

[0037] In this embodiment, the diameter of the palladium alloy tube 8 is 1 mm to 6 mm, and the wall thickness is 0.04 mm to 0.1 mm. To improve the hydrogen permeation rate of the palladium alloy tube 8, the wall thickness of the palladium alloy tube 8 is usually controlled below 0.1 mm. The current tube manufacturing method cannot economically mass-produce tubes with a wall thickness below 0.04 mm. In addition, the smaller the thickness, the lower the strength of the tube, and it cannot withstand a large pressure difference. The outer diameter of the palladium alloy tube 8 is matched with the tube wall; generally, the smaller the diameter, the thinner the wall thickness.

[0038] In this embodiment, the palladium alloy tube 8 is spirally wound around the heating tube 6. The diameter of the spiral coil is 50mm to 100mm, the number of turns is 20 to 100, and the pitch is 1mm to 10mm. The spiral winding of the palladium alloy tube 8 around the heating tube 6 ensures that the gas inside the tube is sufficiently heated. To reduce the overall volume of the purifier, the diameter of the spiral coil should be as small as possible, but this increases the difficulty of winding the coil. A smaller diameter spiral tube can easily cause the palladium alloy tube 8 to crack or collapse. The diameter of the spiral coil must match the diameter of the palladium alloy tube 8. Generally, the smaller the diameter of the palladium alloy tube 8, the smaller the diameter of the spiral coil. Based on the aforementioned diameter of the palladium alloy tube 8, the diameter range of the spiral coil is determined. The number of turns of the spiral coil is determined according to the processing capacity of the purifier; a larger processing capacity requires more turns. The pitch is determined according to the length of the heating tube 6, ensuring that the entire spiral palladium tube is uniformly wound around the heating tube.

[0039] It should be noted that the palladium alloy tube 8 is made of pure Pd tube, with a diameter of 1.5 mm and a wall thickness of 0.04 mm. The length of the palladium alloy tube 8 is approximately 4000 mm. The palladium alloy tube 8 is spirally wound on the heating tube 6, with a spiral diameter of 50 mm, 20 turns, and a pitch of 1 mm.

[0040] It should be noted that the palladium alloy tube 8 is made of PdAg25 alloy tube, with a diameter of 4mm and a wall thickness of 0.08mm. The length of the palladium alloy tube 8 is approximately 16000mm, and it is made of 4 tubes welded together. The palladium alloy tube 8 is spirally wound on the heating tube 6, with a spiral diameter of 100mm, 50 turns, and a pitch of 4mm.

[0041] It should be noted that the palladium alloy tube 8 is made of PdCu40 alloy tube, with a diameter of 6mm and a wall thickness of 0.1mm. The length of the palladium alloy tube 8 is approximately 25000mm, and it is made of 8 tubes welded together. The palladium alloy tube 8 is spirally wound on the heating tube 6, with a spiral diameter of 80mm, 100 turns, and a pitch of 10mm.

[0042] In this embodiment, the palladium alloy tube 8 is connected to the exhaust gas interface 11 at one end and to the raw material gas preheating coil 12 at the other end by brazing. Because the exhaust gas interface 11 and the raw material gas preheating coil 12 are made of stainless steel or heat-resistant steel, which are not the same material as the palladium alloy tube 8, and the wall thickness of the palladium alloy tube 8 is relatively thin, it is impossible to ensure the airtight connection between the two by fusion welding. Therefore, brazing is used for the connection.

[0043] In this embodiment, the inner shell 2, heating tube 6, temperature measuring sleeve 14, preheating chamber 5, and end flange 9 are all made of stainless steel or heat-resistant steel. Stainless steel and heat-resistant steel can be used for a long time at high temperatures and have excellent resistance to hydrogen embrittlement, which can meet the operating conditions of the purifier.

[0044] It should be noted that the inner shell 2, heating tube 6, temperature measuring sleeve 14, preheating chamber 5 and end flange 9 are all made of 316 stainless steel, 304 stainless steel or 310 heat-resistant steel.

[0045] In this embodiment, the inner shell 2 is sealed with the heating tube 6, the temperature measuring sleeve 14, the preheating chamber 5, and the end flange 9 using argon arc welding. Since the materials of the inner shell 2, heating tube 6, temperature measuring sleeve 14, preheating chamber 5, and end flange 9 have been specified as stainless steel and heat-resistant steel, and these materials are typically connected using argon arc welding, this method offers advantages such as simple operation, aesthetically pleasing welds, and reliable quality, thus meeting the process performance requirements of the purifier.

[0046] In this embodiment, the diameters of the pure hydrogen inlet 10, the exhaust gas inlet 11, and the raw material hydrogen inlet 13 are 4mm to 25mm. Since the spiral palladium alloy has different specifications and dimensions, the amount of gas it can process also varies. Therefore, the dimensions of the gas inlets should also be adjusted to improve the purifier's processing efficiency.

[0047] It should be noted that the diameters of the pure hydrogen interface 10 and the exhaust gas interface 11 are both 4mm to 20mm, preferably 4mm, 10mm or 20mm, and the diameter of the raw material hydrogen interface 13 is 8mm to 25mm, preferably 8mm, 12mm or 25mm.

[0048] In actual use, the raw material gas enters the preheating coil 12 through the raw material gas interface 10 and is fully preheated in the preheating chamber 5. The preheated raw material gas then enters the spiral palladium alloy tube 8, which is heated by the heating tube 6. At this time, pure hydrogen permeates from the inner wall of the palladium alloy tube 8 into the diffusion chamber 4 and is discharged from the pure hydrogen interface 13, while the impurity gas that has not permeated is discharged from the tail gas interface 11, thus achieving complete purification and separation of high-purity hydrogen.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An internally heated palladium membrane air purifier, characterized in that, The palladium membrane purifier includes an outer shell (1), an inner shell (2) inside the outer shell (1), and a heat insulation layer (3) between the outer shell (1) and the inner shell (2). The inner shell (2) includes a diffusion chamber (4) and a preheating chamber (5). The palladium membrane purifier also includes a heating tube (6) with one end inserted into the diffusion chamber (4). The heating tube (6) has an electric heating element (7) built into it. A palladium alloy tube (8) is spirally wound around the end of the heating tube (6) inserted into the diffusion chamber (4). The end of the diffusion chamber (4) opposite to the end of the heating tube (6) is a face flange (9). The face flange (9) is provided with a pure hydrogen port (10) and a tail gas port (11) extending out of the outer shell (1). The pure hydrogen interface (10) connects the diffusion chamber (4) and the outside of the outer shell (1). The tail gas interface (11) is connected to one end of the palladium alloy tube (8). The other end of the palladium alloy tube (8) is connected to the raw material gas preheating coil (12) in the preheating chamber (5). The other end of the preheating coil extends out of the outer shell (1) and is provided with a raw material hydrogen interface (13). The palladium membrane purifier also includes a temperature measuring sleeve (14) with one end extending into the diffusion chamber (4). The palladium alloy tube (8) is a self-supporting dense tube. The palladium alloy tube (8) is made by winding a whole palladium alloy tube (8) or by welding multiple palladium alloy tubes (8) together and then winding them. The number of welding points of the welded spiral palladium alloy tube (8) is less than 10.

2. The internally heated palladium membrane purifier according to claim 1, characterized in that, The palladium alloy tube (8) is made of palladium or a palladium alloy, and the palladium alloy contains at least one element selected from Ag, Cu, Y, Au, Ru and Ce.

3. The internally heated palladium membrane purifier according to claim 1, characterized in that, The palladium alloy tube (8) has a diameter of 1 mm to 6 mm and a wall thickness of 0.04 mm to 0.1 mm.

4. The internally heated palladium membrane purifier according to claim 1, characterized in that, The palladium alloy tube (8) is spirally wound on the heating tube (6), wherein the diameter of the spiral coil is 50mm~100mm, the number of spiral coil turns is 20~100 turns, and the pitch is 1mm~10mm.

5. The internally heated palladium membrane purifier according to claim 1, characterized in that, The palladium alloy tube (8) is connected to the exhaust gas interface (11) by brazing at one end and to the raw material gas preheating coil (12) at the other end.

6. The internally heated palladium membrane purifier according to claim 1, characterized in that, The inner shell (2), heating tube (6), temperature measuring sleeve (14), preheating chamber (5) and end flange (9) are all made of stainless steel or heat-resistant steel.

7. The internally heated palladium membrane purifier according to claim 1, characterized in that, The inner shell (2) is sealed with the heating tube (6), the temperature measuring sleeve (14), the preheating chamber (5) and the end flange (9) by argon arc welding.

8. The internally heated palladium membrane purifier according to claim 1, characterized in that, The diameters of the pure hydrogen interface (10), the exhaust gas interface (11), and the raw material hydrogen interface (13) are 4mm to 25mm.

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