Hydrogen turbine expander

Abstract

The invention relates to the technical field of low-temperature refrigeration, in particular to a hydrogen turbo expander. The first heat exchange channel is formed among the shell, the bearing unit, the motor stator and the rotating shaft, and the cavity is formed in the rotating shaft, so that the first heat exchange channel is communicated with the cavity, an external circulating cooling medium can be used for carrying out heat exchange on hydrogen in the first heat exchange channel, and extra cooling gas is prevented from being provided for the motor stator; the complexity and energy consumption of the device are reduced, heat conduction between the expansion end and the motor rotor can be effectively isolated through the cavity, airflow exchange can be conducted between the cavity and the first heat exchange channel, the temperature of the area where the bearing unit is located can be effectively controlled, and the service life of the bearing unit is prolonged. And the temperature of the bearing unit cannot enter a low-temperature area to fail due to heat conduction of the expansion end. And meanwhile, the bearing unit is a magnetic bearing, and the magnetic bearing has the advantages of no contact, no abrasion, large bearing capacity and the like, so that the magnetic bearing is suitable for large and ultra-large hydrogen liquefaction scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature refrigeration, and in particular to a hydrogen turbine expander. Background Art

[0002] In large and super-large hydrogen liquefaction systems, expansion cycle refrigeration based on hydrogen medium is usually adopted, and its core component is the hydrogen turbine expander (or hydrogen turbine expansion device). The hydrogen turbine expander is a rotating device that uses cryogenic compressed hydrogen to expand and work externally to obtain cooling capacity. It mainly includes an expansion end, a bearing unit, a rotating shaft and a brake unit.

[0003] However, how to effectively reduce the complexity and energy consumption of the device while being suitable for large and ultra-large hydrogen liquefaction scenarios is a technical problem that urgently needs to be solved for the hydrogen turbine expander. Summary of the invention

[0004] The embodiment of the present invention provides a hydrogen turbine expander, which can effectively reduce the complexity and energy consumption of the device and is suitable for large and ultra-large hydrogen liquefaction scenarios.

[0005] An embodiment of the present invention provides a hydrogen turbine expander, comprising an expansion end, a shell, and a bearing unit, a brake unit, and at least a portion of a rotating shaft arranged inside the shell, wherein the expansion end is arranged on the circumference of the rotating shaft located outside the shell, the brake unit comprises a motor stator and a motor rotor, the motor stator is arranged on the circumference of the rotating shaft, the motor rotor is arranged inside the rotating shaft, the bearing unit is arranged on the circumference of the rotating shaft and located on both sides of the motor stator, a heat insulating component and a dynamic seal are arranged between the expansion end and the bearing unit, and the type of the bearing unit is a magnetic bearing; A first heat exchange channel is formed between the shell, the bearing unit, the motor stator and the rotating shaft, and the first heat exchange channel is used to circulate the internally circulated hydrogen to exchange heat between the motor stator and the motor rotor. A cavity is provided inside the rotating shaft, and the cavity is located between the expansion end and the electronic rotor. The first heat exchange channel is connected to the cavity. A second heat exchange channel is formed on the shell, and the second heat exchange channel is used to circulate a cooling medium to exchange heat between the hydrogen in the first heat exchange channel.

[0006] Compared with the related art, the present invention has at least the following beneficial effects: According to the hydrogen turbine expander provided by the embodiment of the present invention, by forming a first heat exchange channel between the housing, the bearing unit, the motor stator and the rotating shaft, and arranging a cavity inside the rotating shaft, and making the first heat exchange channel communicate with the cavity, it is possible to utilize the cooling medium flowing externally to exchange heat with the hydrogen in the first heat exchange channel, thereby avoiding providing additional cooling gas for the motor stator, reducing the complexity and energy consumption of the device, and effectively isolating the heat conduction between the expansion end and the motor rotor by using the cavity. The cavity can also exchange air flow with the first heat exchange channel to effectively control the temperature of the area where the bearing unit is located, so as to ensure that the temperature of the bearing unit will not enter the low-temperature region and fail due to the heat conduction of the expansion end. At the same time, since the type of the bearing unit is a magnetic bearing, and the magnetic bearing has the advantages of non-contact, non-wear and large bearing capacity, it is therefore applicable to large-scale and extra-large-scale hydrogen liquefaction scenarios. Therefore, the above technical solution can effectively reduce the complexity and energy consumption of the device and is applicable to large-scale and extra-large-scale hydrogen liquefaction scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0008] Figure 1 It is a schematic structural diagram of the hydrogen turbine expander provided by the embodiment of the present invention.

[0009] Reference Signs: 1 - expansion end; 2 - housing; 21 - second fin structure; 22 - third fin structure; 23 - sealing plug; 24 - cable; 3 - bearing unit; 31 - radial magnetic bearing; 32 - axial magnetic bearing; 33 - isolation block; 34 - axial force plate; 35 - hydrogen-blocking coating; 4 - braking unit; 41 - motor stator; 42 - motor rotor; 5 - rotating shaft; 51 - cavity; 52 - booster impeller; 53 - first fin structure; 6 - adiabatic component; 7 - dynamic seal; 8 - first heat exchange channel; 9 - second heat exchange channel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0010] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0011] As shown Figure 1 in the figure, an embodiment of the present invention provides a hydrogen turbine expander, which includes an expansion end 1, a housing 2, and a bearing unit 3, a braking unit 4, and at least a part of a rotating shaft 5 disposed inside the housing 2. The expansion end 1 is disposed on the circumference of the part of the rotating shaft 5 outside the housing 2. The braking unit 4 includes a motor stator 41 and a motor rotor 42. The motor stator 41 is disposed on the circumference of the rotating shaft 5, and the motor rotor 42 is disposed inside the rotating shaft 5. The bearing unit 3 is disposed on the circumference of the rotating shaft 5 and on both sides of the motor stator 41. An adiabatic component 6 and a dynamic seal 7 are disposed between the expansion end 1 and the bearing unit 3. The type of the bearing unit 3 is a magnetic bearing; A first heat exchange channel 8 is formed among the housing 2, the bearing unit 3, the motor stator 41, and the rotating shaft 5. The first heat exchange channel 8 is used for circulating internally recycled hydrogen to exchange heat with the motor stator 41 and the motor rotor 42. A cavity 51 is disposed inside the rotating shaft 5. The cavity 51 is located between the expansion end 1 and the electronic rotor. The first heat exchange channel 8 is communicated with the cavity 51. A second heat exchange channel 9 is formed on the housing 2. The second heat exchange channel 9 is used for circulating a cooling medium to exchange heat with the hydrogen in the first heat exchange channel 8.

[0012] In this embodiment, by forming the first heat exchange channel 8 among the housing 2, the bearing unit 3, the motor stator 41, and the rotating shaft 5, disposing the cavity 51 inside the rotating shaft 5, and making the first heat exchange channel 8 communicated with the cavity 51, on one hand, the cooling medium flowing externally can be used to exchange heat with the hydrogen in the first heat exchange channel 8, thereby avoiding providing additional cooling gas for the motor rotor 42, reducing the complexity and energy consumption of the device. On the other hand, the cavity 51 can be used to effectively isolate the heat conduction between the expansion end 1 and the motor rotor 42. Moreover, the cavity 51 can exchange air flow with the first heat exchange channel 8 to effectively control the temperature of the area where the bearing unit 3 is located, so as to ensure that the temperature of the bearing unit 3 does not enter the low-temperature zone and fail due to the heat conduction of the expansion end 1. At the same time, since the type of the bearing unit 3 is a magnetic bearing, and the magnetic bearing has the advantages of non-contact, non-wear, and large load-bearing capacity, etc., it is applicable to large-scale and extra-large-scale hydrogen liquefaction scenarios. Therefore, the above technical solution can effectively reduce the complexity and energy consumption of the device and is applicable to large-scale and extra-large-scale hydrogen liquefaction scenarios.

[0013] It should be noted that the types of the bearing unit 3 generally include gas bearings, magnetic bearings, and oil bearings, among which: gas bearings use hydrogen as the medium, including hydrostatic gas bearings and hydrodynamic gas bearings. Hydrostatic gas bearings need to extract high-pressure normal-temperature hydrogen from the main path, increasing the system energy consumption. Moreover, since there is a low-pressure area inside the housing 2 of the hydrogen turbine expander, in order to prevent high-pressure low-temperature gas from entering the bearing from the expansion end 1 and affecting its stability, an additional stream of normal-temperature sealing gas needs to be provided, further increasing the energy consumption. Hydrodynamic gas bearings do not consume hydrogen additionally, but their load-carrying capacity is small and it is difficult to be applicable to large and extra-large hydrogen liquefaction scenarios. Oil bearings have a large load-carrying capacity, but they need to use an additional oil supply system. Once there is a leakage, the entire hydrogen liquefaction system will be contaminated. Magnetic bearings have the advantages of non-contact, non-wear, and large load-carrying capacity, and are the development direction of large and extra-large hydrogen liquefaction systems.

[0014] In some embodiments, the adiabatic component 6 can be made of a non-metallic material with a low thermal conductivity and is used to isolate the expansion end 1 and the bearing unit 3, thereby reducing heat leakage. The dynamic seal 7 is used to block the low-temperature compressed hydrogen at the expansion end 1 and the gas inside the bearing unit 3. Since both the bearing unit 3 and the braking unit 4 are closed structures and there is no continuous gas flow with the low-temperature expansion end 1, a dynamic seal 7 is provided between them to establish a pressure gradient. A cavity 51 is provided between the motor rotor 42 and the low-temperature expansion end 1, and the cavity 51 communicates with the first heat exchange channel 8. While significantly reducing the heat leakage from the cold end (i.e., the expansion end 1) to the bearing end (i.e., the expansion unit), gas heat exchange can also be carried out with the first heat exchange channel 8 through small holes (i.e., opened on the rotating shaft 5 and communicating with the cavity 51 and the first heat exchange channel 8) to ensure that the bearing temperature will not enter the low-temperature region and fail due to heat conduction from the cold end.

[0015] In some embodiments, the cooling medium can be cooling water, cooling oil, and no specific limitation is made here.

[0016] In an embodiment of the present invention, a booster impeller 52 is provided outside the rotating shaft 5 located in the first heat exchange channel 8. By setting it in this way, the hydrogen (i.e., the internal circulating hydrogen) in the first heat exchange channel 8 can be forced to circulate to enhance the heat exchange between the internal circulating hydrogen and the external cooling medium.

[0017] In an embodiment of the present invention, the booster impeller 52 includes two groups, and the two groups of booster impellers 52 are respectively located at both ends of the rotating shaft 5 in the first heat exchange channel 8. By setting it in this way, the heat exchange between the internal circulating hydrogen and the external cooling medium can be further enhanced.

[0018] In an embodiment of the present invention, a first fin structure 53 is formed outside the rotating shaft 5 located in the first heat exchange channel 8. By setting it in this way, the forced convection heat exchange between the internal circulating hydrogen and the motor stator 41 can be enhanced.

[0019] In an embodiment of the present invention, the first fin structure 53 is formed on the surface of the rotating shaft 5 by etching, and the first fin structure 53 includes at least one of straight fins and spiral channels.

[0020] In an embodiment of the present invention, the housing 2 located in the first heat exchange channel 8 forms a second fin structure 21, and the housing 2 located in the second heat exchange channel 9 forms a third fin structure 22. With such an arrangement, the forced convective heat transfer between the internally circulated hydrogen and the cooling medium can be enhanced by the second fin structure 21, and the forced convective heat transfer between the cooling medium and the housing 2 can be enhanced by the third fin structure 22.

[0021] In an embodiment of the present invention, the second fin structure 21 is formed on the inner surface of the housing 2 by machining or etching, the third fin structure 22 is formed on the outer surface of the housing 2 by machining or etching, and both the second fin structure 21 and the third fin structure 22 include at least one of straight fins and spiral channels.

[0022] In an embodiment of the present invention, the bearing unit 3 includes two radial magnetic bearings 31 and two axial magnetic bearings 32. The two radial magnetic bearings 31 are located on both sides of the motor stator 41. The adiabatic component 6 and the dynamic seal 7 are arranged between the expansion end 1 and one of the radial magnetic bearings 31. The two axial magnetic bearings 32 are arranged outside the other radial magnetic bearing 31, and an isolation block 33 and an axial force disk 34 are arranged on the outer periphery of the axial magnetic bearing 32.

[0023] In an embodiment of the present invention, a sealing plug 23 is provided on the housing 2 (for example, installed on the housing 2 through a gasket and screws). A cable 24 is connected between the motor stator 41 and the sealing plug 23. The cable 24 passes through the first heat exchange channel 8, and the outer skin of the cable 24 is made of an insulating material.

[0024] In this embodiment, the rotating shaft 5 is used to transmit mechanical energy. The internally enclosed motor rotor 42 and the external motor stator 41 form a braking motor (i.e., the braking unit 4), and electric energy is transmitted externally through the cable 24.

[0025] In an embodiment of the present invention, the outer surfaces of the two radial magnetic bearings 31 and the two axial magnetic bearings 32 are both coated with a hydrogen-resistant coating 35. The sealing plug 23 uses an explosion-proof glass-sealed aviation plug, and the insulating material includes Teflon.

[0026] Considering that the magnetic bearings are in direct contact with high-purity hydrogen and are prone to hydrogen embrittlement, hydrogen-resistant coatings 35 are coated on the outer surfaces of the two radial magnetic bearings 31 and the two axial magnetic bearings 32 to ensure that conventional magnetic bearings can be applied to hydrogen turbine expanders.

[0027] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0028] Finally, it should be noted that the above description is only a preferred embodiment of the present invention, and is only used to illustrate the technical solution of the present invention, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included within the protection scope of the present invention.

Claims

1. A hydrogen turbine expander, characterized in that, It includes an expansion end, a housing, and a bearing unit, a braking unit, and at least a part of a rotating shaft disposed inside the housing. The expansion end is disposed on the circumference of the part of the rotating shaft outside the housing. The braking unit includes a motor stator and a motor rotor. The motor stator is disposed on the circumference of the rotating shaft. The motor rotor is disposed inside the rotating shaft. The bearing unit is disposed on the circumference of the rotating shaft and on both sides of the motor stator. An adiabatic component and a dynamic seal are disposed between the expansion end and the bearing unit. The type of the bearing unit is a magnetic bearing; A first heat exchange channel is formed between the housing, the bearing unit, the motor stator, and the rotating shaft. The first heat exchange channel is used for circulating internally recycled hydrogen to exchange heat between the motor stator and the motor rotor. A cavity is disposed inside the rotating shaft. The cavity is located between the expansion end and the electronic rotor. The first heat exchange channel is communicated with the cavity. A second heat exchange channel is formed on the housing. The second heat exchange channel is used for circulating a cooling medium to exchange heat with the hydrogen in the first heat exchange channel.

2. The hydrogen turbine expander according to claim 1, wherein A booster impeller is disposed outside the rotating shaft in the first heat exchange channel.

3. The hydrogen turbine expander according to claim 2, wherein There are two groups of the booster impellers. The two groups of the booster impellers are respectively located at both ends of the rotating shaft in the first heat exchange channel.

4. The hydrogen turbine expander according to claim 2, characterized in that, A first fin structure is formed outside the rotating shaft in the first heat exchange channel.

5. The hydrogen turbine expander according to claim 4, characterized in that, The first fin structure is formed on the surface of the rotating shaft by etching. The first fin structure includes at least one of straight fins and spiral channels.

6. The hydrogen turbine expander according to claim 4, characterized in that, The housing in the first heat exchange channel forms a second fin structure, and the housing in the second heat exchange channel forms a third fin structure.

7. The hydrogen turbine expander according to claim 6, characterized in that, The second fin structure is formed on the inner surface of the housing by machining or etching. The third fin structure is formed on the outer surface of the housing by machining or etching. Both the second fin structure and the third fin structure include at least one of straight fins and spiral channels.

8. The hydrogen turbine expander according to any one of claims 1-7, characterized in that, The bearing unit includes two radial magnetic bearings and two axial magnetic bearings. The two radial magnetic bearings are located on both sides of the motor stator. The adiabatic component and the dynamic seal are disposed between the expansion end and one of the radial magnetic bearings. The two axial magnetic bearings are disposed outside the other radial magnetic bearing. An isolation block and an axial force disk are disposed on the outer circumference of the axial magnetic bearing.

9. The hydrogen turbine expander according to claim 8, characterized in that, A sealed plug is disposed on the housing. A cable is connected between the motor stator and the sealed plug. The cable passes through the first heat exchange channel. The outer skin of the cable is made of an insulating material.

10. The hydrogen turbine expander according to claim 9, characterized in that, The outer surfaces of the two radial magnetic bearings and the two axial magnetic bearings are coated with a hydrogen barrier coating. The sealed plug is an explosion-proof glass-sealed aviation plug. The insulating material includes Teflon.

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