A hydrogen turbine expander

Abstract

The present invention relates to the field of low-temperature refrigeration technology, and in particular to a hydrogen turbine expander. By forming a first heat exchange channel between a housing, a bearing unit, a motor stator, and a rotating shaft, and providing a cavity inside the rotating shaft, the first heat exchange channel is connected to the cavity. The cooling medium circulating outside can be used to exchange heat with the hydrogen in the first heat exchange channel, avoiding the need to provide additional cooling gas for the motor stator, thereby reducing the complexity and energy consumption of the device. The cavity can also be used to effectively isolate the heat conduction between the expansion end and the motor rotor, and the cavity can also be exchanged with the first heat exchange channel to effectively control the temperature of the area where the bearing unit is located, ensuring that the temperature of the bearing unit will not enter the low-temperature zone and fail due to the heat conduction of the expansion end. At the same time, since the bearing unit is a magnetic bearing, the magnetic bearing has the advantages of no contact, no wear, and large bearing capacity, and is therefore suitable for large and ultra-large hydrogen liquefaction scenarios.

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] Large and ultra-large hydrogen liquefaction systems typically utilize a hydrogen-based expansion cycle refrigeration method. The core component is the hydrogen turbine expander (or hydrogen turbine expansion device). This rotating device generates cooling energy by expanding cryogenically compressed hydrogen. It primarily consists of 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 also making it suitable for large and ultra-large hydrogen liquefaction scenarios is a technical problem that urgently needs to be solved for this hydrogen turbine expander. Summary of the Invention

[0004] An embodiment of the present invention provides a hydrogen turbine expander that 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 housing, and a bearing unit, a brake unit, and at least a portion of a rotating shaft disposed inside the housing. The expansion end is disposed on the circumference of the rotating shaft located outside the housing. The brake unit comprises 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 units are disposed on the circumference of the rotating shaft and on both sides of the motor stator. A heat insulating component and a dynamic seal are disposed between the expansion end and the bearing unit. The bearing unit is a magnetic bearing.

[0006] 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 to circulate internally circulating hydrogen to exchange heat between the motor stator and the motor rotor. A cavity is provided inside the rotating shaft. The cavity is located between the expansion end and the motor rotor. The first heat exchange channel is connected to the cavity. A second heat exchange channel is formed on the housing. The second heat exchange channel is used to circulate a cooling medium to exchange heat with the hydrogen in the first heat exchange channel.

[0007] Compared with the related art, the present invention has at least the following beneficial effects:

[0008] According to the hydrogen turbine expander provided by the embodiment of the present invention, a first heat exchange channel is formed between the housing, the bearing unit, the motor stator and the rotating shaft, and a cavity is provided inside the rotating shaft, and the first heat exchange channel is connected to the cavity. In this way, the hydrogen in the first heat exchange channel can be heat exchanged by the external circulating cooling medium, thereby avoiding providing additional cooling gas for the motor stator, reducing the complexity and energy consumption of the device, and the cavity can be used to effectively isolate the heat conduction between the expansion end and the motor rotor. The cavity and the first heat exchange channel can also exchange airflow to effectively control the temperature of the area where the bearing unit is located, thereby ensuring that the temperature of the bearing unit will not enter the low temperature zone and fail due to the heat conduction of the expansion end. At the same time, since the bearing unit is a magnetic bearing, the magnetic bearing has the advantages of no contact, no wear, and large bearing capacity, and is therefore suitable for large and extra-large hydrogen liquefaction scenarios. Therefore, the above technical solution can effectively reduce the complexity and energy consumption of the device and is suitable for large and extra-large hydrogen liquefaction scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 A schematic structural diagram of a hydrogen turbine expander provided in an embodiment of the present invention.

[0011] Reference numerals:

[0012] 1-expansion end; 2-housing; 21-second rib structure; 22-third rib structure; 23-sealing plug; 24-cable; 3-bearing unit; 31-radial magnetic bearing; 32-axial magnetic bearing; 33-isolating block; 34-axial force disk; 35-hydrogen barrier coating; 4-brake unit; 41-motor stator; 42-motor rotor; 5-rotating shaft; 51-cavity; 52-boost impeller; 53-first rib structure; 6-insulating component; 7-dynamic seal; 8-first heat exchange channel; 9-second heat exchange channel. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0014] like Figure 1 As shown, an embodiment of the present invention provides a hydrogen turbine expander, comprising an expansion end 1, a housing 2, and a bearing unit 3, a brake unit 4, and at least a portion of a rotating shaft 5 arranged inside the housing 2. The expansion end 1 is arranged on the circumference of the rotating shaft 5 located outside the housing 2. The brake unit 4 includes a motor stator 41 and a motor rotor 42. The motor stator 41 is arranged on the circumference of the rotating shaft 5, and the motor rotor 42 is arranged inside the rotating shaft 5. The bearing unit 3 is arranged on the circumference of the rotating shaft 5 and is located on both sides of the motor stator 41. A heat insulating component 6 and a dynamic seal 7 are provided between the expansion end 1 and the bearing unit 3. The bearing unit 3 is a magnetic bearing.

[0015] A first heat exchange channel 8 is formed between the shell 2, the bearing unit 3, the motor stator 41 and the rotating shaft 5. The first heat exchange channel 8 is used to circulate the internally circulated hydrogen to exchange heat between the motor stator 41 and the motor rotor 42. A cavity 51 is provided inside the rotating shaft 5. The cavity 51 is located between the expansion end 1 and the motor rotor. The first heat exchange channel 8 is connected to the cavity 51. A second heat exchange channel 9 is formed on the shell 2. The second heat exchange channel 9 is used to circulate a cooling medium to exchange heat with the hydrogen in the first heat exchange channel 8.

[0016] In this embodiment, by forming a first heat exchange channel 8 between the housing 2, the bearing unit 3, the motor stator 41 and the rotating shaft 5, and providing a cavity 51 inside the rotating shaft 5, and making the first heat exchange channel 8 connected to the cavity 51, the external circulating cooling medium can be used to exchange heat with the hydrogen in the first heat exchange channel 8, thereby avoiding providing additional cooling gas to the motor rotor 42, reducing the complexity and energy consumption of the device, and the cavity 51 can be used to effectively isolate the heat conduction between the expansion end 1 and the motor rotor 42, and the cavity 51 can also be used to exchange airflow with the first heat exchange channel 8 to effectively control the temperature of the area where the bearing unit 3 is located, thereby ensuring that the temperature of the bearing unit 3 will not enter the low temperature zone due to the heat conduction of the expansion end 1 and fail. At the same time, since the bearing unit 3 is a magnetic bearing, the magnetic bearing has the advantages of no contact, no wear, and large bearing capacity, and is therefore suitable for large and ultra-large hydrogen liquefaction scenarios. Therefore, the above technical solution can effectively reduce the complexity and energy consumption of the device and is suitable for large and ultra-large hydrogen liquefaction scenarios.

[0017] It should be noted that the types of bearing units 3 generally include gas bearings, magnetic bearings, and oil bearings, among which: gas bearings use hydrogen as a medium, including static pressure gas bearings and dynamic pressure gas bearings. Static pressure gas bearings need to extract high-pressure room-temperature hydrogen from the main line, which increases the energy consumption of the system. In addition, since there is a low-pressure area inside the shell 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 room-temperature sealing gas needs to be provided, which further increases energy consumption. Dynamic pressure gas bearings do not consume additional hydrogen, but their bearing capacity is small, making them difficult to apply to large and ultra-large hydrogen liquefaction scenarios. Oil bearings have a large bearing capacity, but they require an additional oil supply system. Once leaked, the entire hydrogen liquefaction system will be contaminated. Magnetic bearings have the advantages of no contact, no wear, and large bearing capacity, and are the development direction of large and ultra-large hydrogen liquefaction systems.

[0018] In some embodiments, the insulation component 6 can be made of a non-metallic material with low thermal conductivity, which is used to separate 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 from the gas inside the bearing unit 3. Since the bearing unit 3 and the brake unit 4 are both closed structures and there is no continuous gas flow with the low-temperature expansion end 1, a dynamic seal 7 is set between the two to establish a pressure gradient. A cavity 51 is set between the motor rotor 42 and the low-temperature expansion end 1, and the cavity 51 is connected to the first heat exchange channel 8. While the cavity 51 significantly reduces the heat leakage from the cold end (i.e., the expansion end 1) to the bearing end (i.e., the expansion unit), it can also perform gas heat exchange with the first heat exchange channel 8 through a small hole (i.e., opened on the rotating shaft 5 and connected to the cavity 51 and the first heat exchange channel 8, respectively), thereby ensuring that the bearing temperature will not fail due to heat conduction from the cold end and enter the low-temperature temperature zone.

[0019] In some embodiments, the cooling medium may be cooling water or cooling oil, which is not specifically limited herein.

[0020] In one embodiment of the present invention, a booster impeller 52 is disposed outside the rotating shaft 5 in the first heat exchange channel 8. This configuration forces the hydrogen in the first heat exchange channel 8 (i.e., the internally circulating hydrogen) to self-circulate, thereby enhancing heat exchange between the internally circulating hydrogen and the external cooling medium.

[0021] In one embodiment of the present invention, the booster impellers 52 include two groups, which are respectively located at both ends of the rotating shaft 5 at the first heat exchange channel 8. This arrangement can further enhance the heat exchange between the internal circulating hydrogen and the external cooling medium.

[0022] In one embodiment of the present invention, a first fin structure 53 is formed outside the rotating shaft 5 in the first heat exchange channel 8. This arrangement can enhance the forced convection heat exchange between the internal circulating hydrogen and the motor stator 41.

[0023] In one embodiment of the present invention, the first rib structure 53 is formed on the surface of the rotating shaft 5 by etching, and the first rib structure 53 includes at least one of straight ribs and spiral grooves.

[0024] In one 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 this arrangement, the second fin structure 21 can be used to enhance the forced convection heat exchange between the internally circulating hydrogen and the cooling medium, and the third fin structure 22 can be used to enhance the forced convection heat exchange between the cooling medium and the housing 2.

[0025] In one embodiment of the present invention, the second fin structure 21 is formed on the inner surface of the shell 2 by machining or etching, and the third fin structure 22 is formed on the outer surface of the shell 2 by machining or etching, and the second fin structure 21 and the third fin structure 22 both include at least one of straight ribs and spiral grooves.

[0026] In one 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 insulation 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 on the outside of the other radial magnetic bearing 31. The outer periphery of the axial magnetic bearing 32 is provided with an isolation block 33 and an axial force disk 34.

[0027] In one embodiment of the present invention, a sealing plug 23 is provided on the housing 2 (for example, installed on the housing 2 by a sealing gasket and screws), and a cable 24 is connected between the motor stator 41 and the sealing plug 23. The cable 24 is passed through the first heat exchange channel 8, and the outer sheath of the cable 24 is made of insulating material.

[0028] 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 brake motor (ie, the brake unit 4 ), and transmit electrical energy to the outside through the cable 24 .

[0029] In one embodiment of the present invention, the outer surfaces of the two radial magnetic bearings 31 and the two axial magnetic bearings 32 are coated with a hydrogen barrier coating 35 , and the sealing plug 23 is an explosion-proof glass-sealed aviation plug, and the insulating material includes Teflon.

[0030] Considering that the magnetic bearings are in direct contact with high-purity hydrogen and are prone to hydrogen embrittlement, the outer surfaces of the two radial magnetic bearings 31 and the two axial magnetic bearings 32 are coated with a hydrogen barrier coating 35 to ensure that conventional magnetic bearings can be applied to hydrogen turbine expanders.

[0031] It should be noted that, in this article, relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device comprising the elements.

[0032] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is intended only to illustrate the technical solution of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A hydrogen turboexpander, characterized in that: The invention comprises an expansion end, a housing, a bearing unit, a brake unit and at least a part of a rotating shaft arranged inside the housing, wherein the expansion end is arranged on the circumference of the rotating shaft located outside the housing, the brake unit comprises a motor stator and a motor rotor, the motor stator is arranged radially outside 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 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 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 to circulate hydrogen circulating inside to exchange heat between the motor stator and the motor rotor. A cavity is provided inside the rotating shaft. The cavity is located between the expansion end and the motor 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 to circulate a cooling medium to exchange heat with the hydrogen in the first heat exchange channel. A boost impeller is provided outside the rotating shaft located in the first heat exchange channel; The boost impellers include two groups, and the two groups of boost impellers are respectively located at two ends of the rotating shaft in the first heat exchange channel.

2. The hydrogen turboexpander according to claim 1, characterized in that: A first fin structure is formed outside the rotating shaft located in the first heat exchange channel.

3. The hydrogen turboexpander according to claim 2, characterized in that: The first fin structure is formed on the surface of the rotating shaft by etching, and the first fin structure includes at least one of straight ribs and spiral grooves.

4. The hydrogen turboexpander according to claim 2, characterized in that: The shell located in the first heat exchange channel forms a second fin structure, and the shell located in the second heat exchange channel forms a third fin structure.

5. The hydrogen turboexpander according to claim 4, characterized in that: The second fin structure is formed on the inner surface of the shell by machining or etching, and the third fin structure is formed on the outer surface of the shell by machining or etching. The second fin structure and the third fin structure both include at least one of straight ribs and spiral grooves.

6. The hydrogen turboexpander according to any one of claims 1 to 5, 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 insulation component and the dynamic seal are arranged between the expansion end and one of the radial magnetic bearings. The two axial magnetic bearings are arranged on the outside of the other radial magnetic bearing. The outer periphery of the axial magnetic bearing is provided with an isolation block and an axial force disk.

7. The hydrogen turboexpander according to claim 6, characterized in that: A sealing plug is provided on the shell, and a cable is connected between the motor stator and the sealing plug. The cable is passed through the first heat exchange channel, and the outer sheath of the cable is made of insulating material.

8. The hydrogen turboexpander according to claim 7, 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 sealing plug adopts an explosion-proof glass-sealed aviation plug, and the insulating material includes Teflon.

Images