Liquefied gas seal system

Abstract

The liquefied gas seal system 10 seals a liquefied gas chamber 7 around a rotating shaft 4 which passes from the inside of the liquefied gas chamber 7 to the outside. A liquefied gas seal system 10 includes: a gas / liquid chamber 11 which communicates with the liquefied gas chamber 7; a gas chamber 12 which communicates with the gas / liquid chamber 11 and is filled with sealing gas; and a labyrinth 13 which allows communication between the gas chamber 11 and the outside of the liquefied gas chamber 7. The liquefied gas seal system 10 preferably further includes a buffer chamber 8 which communicates with the gas chamber 12 via the labyrinth 13.

Description

Liquefied Gas Seal System

[0001] The present specification discloses a liquefied gas seal system.

[0002] Patent Document 1 discloses a turbopump. This turbopump is used to supply liquefied gas such as liquid hydrogen or liquid oxygen. This turbopump includes an impeller that pumps the liquefied gas, a shaft that rotates together with the impeller, and a bearing that supports the shaft. The shaft penetrates the wall of a liquefied gas chamber. In this turbopump, a labyrinth prevents the liquefied gas from leaking around the shaft. This turbopump also includes a slinger located between the labyrinth and the bearing, and a decompression chamber that houses the slinger. In this turbopump, the bearing chamber and the decompression chamber are separated by a partition wall to prevent fluid movement from the decompression chamber to the bearing chamber.

[0003] JP 2016-41909 A

[0004] The turbopump of Patent Document 1 transmits rotational power energy to the impeller via a shaft. This creates a gap around the shaft. In turbomachinery such as a turbopump, a seal such as a labyrinth disclosed in Patent Document 1 prevents leakage of liquefied gas.

[0005] It is the applicant's intent to provide a liquefied gas sealing system that reduces leakage of liquefied gas.

[0006] The liquefied gas seal system disclosed in this specification seals a liquefied gas chamber around a rotating shaft that penetrates from the inside to the outside of the liquefied gas chamber. This liquefied gas seal system includes a gas-liquid chamber that communicates with the liquefied gas chamber, a gas chamber that communicates with the gas-liquid chamber and is filled with a seal gas, and a labyrinth that communicates between the gas chamber and the outside of the liquefied gas chamber.

[0007] This liquefied gas seal system can reduce leakage of liquefied gas.

[0008] Fig. 1 is a configuration diagram showing a liquefied gas turbine equipped with a liquefied gas seal system according to one embodiment. Fig. 2 is a partial cross-sectional view showing the liquefied gas seal system equipped in the liquefied gas turbine of Fig. 1. Fig. 3 is a configuration diagram of the liquefied gas seal system equipped in the liquefied gas turbine of Fig. 1.

[0009] Hereinafter, preferred embodiments will be described in detail with reference to the drawings as appropriate.

[0010] 1 shows a liquefied gas turbine 1. This liquefied gas turbine 1 is used, for example, in a liquid hydrogen production facility for obtaining liquefied hydrogen. Note that, although the liquefied gas turbine 1 will be described using liquefied hydrogen as an example, the liquefied gas used in the liquefied gas turbine 1 is not limited to liquefied hydrogen.

[0011] The liquefied gas turbine 1 includes a turbine 2, a blower 3, a shaft 4, a bearing 5, a heat exchanger 6, a liquefied gas chamber 7, a bearing chamber 8, and a brake chamber 9. The liquefied gas turbine 1 further includes a liquefied gas seal system 10. In this liquefied gas turbine 1, the liquefied gas chamber 7, the bearing chamber 8, and the brake chamber 9 are located in this order from bottom to top. The turbine 2 is located in the liquefied gas chamber 7. The blower 3 and the heat exchanger 6 are located in the brake chamber 9. The bearing 5 is located in the bearing chamber 8.

[0012] The shaft 4 is supported in the axial and radial directions by bearings 5. The shaft 4 extends vertically. The shaft 4 is rotatable. This bearing 5 is not particularly limited, but for example, a fluid bearing is used. Although not particularly limited, a bearing chamber 8 is filled with hydrogen gas as a fluid used in the fluid bearing. The shaft 4 extends from the liquefied gas chamber 7 to the brake chamber 9 via the bearing chamber 8. The shaft 4 connects the turbine 2 and the blower 3. A liquefied gas seal system 10 is located around the shaft 4, which extends from the inside to the outside of the liquefied gas chamber 7.

[0013] In this liquefied gas turbine 1, high-pressure, low-temperature liquid hydrogen flows into the liquefied gas chamber 7 from the inlet 7A. This liquid hydrogen rotates the turbine 2. By rotating the turbine 2, energy is transferred from the liquid hydrogen to the turbine 2, and the pressure of the liquid hydrogen decreases. The liquid hydrogen with reduced pressure flows out from the outlet 7B.

[0014] Meanwhile, the rotation of the turbine 2 rotates the shaft 4 and the blower 3. In particular, although the fluid is not limited to hydrogen gas, hydrogen gas is filled as the fluid in the brake chamber 9. The blower 3 causes the hydrogen gas to flow in the brake chamber 9. Thermal energy is removed from the flowing hydrogen gas by the heat exchanger 6. In this way, the pressure of the liquid hydrogen in the liquefied gas chamber 7 is reduced and energy is extracted from the liquid hydrogen.

[0015] The liquefied gas turbine 1 can reduce the pressure of the liquid hydrogen while extracting energy from the high-pressure liquid hydrogen. A liquid hydrogen production facility using the liquefied gas turbine 1 can improve energy efficiency.

[0016] Fig. 2 shows a liquefied gas seal system 10. Fig. 2 shows a cross section taken along the center line L of the shaft 4. The liquefied gas seal system 10 includes a gas-liquid chamber 11, a gas chamber 12, and a labyrinth 13. The liquefied gas turbine 1 includes a housing 14. The gas-liquid chamber 11, the gas chamber 12, and the labyrinth 13 are formed in the housing 14. Note that the housing 14 may be formed by combining separate members. The liquefied gas seal system 10 further includes a bearing chamber 8 serving as a buffer chamber, a damper chamber 15, a labyrinth 16, and a heat insulating material 17.

[0017] The gas-liquid chamber 11 is a space recessed from the inner peripheral surface 14A of the housing 14. The gas-liquid chamber 11 opens to the outer peripheral surface 4A of the shaft 4. The gas-liquid chamber 11 surrounds the shaft 4 in the circumferential direction. Between the gas-liquid chamber 11 and the liquefied gas chamber 7, there is a gap between the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14. This gap allows the gas-liquid chamber 11 to communicate with the liquefied gas chamber 7 around the shaft 4. In this liquefied gas turbine 1, the gas-liquid chamber 11 communicates with the liquefied gas chamber 7 via a labyrinth 16.

[0018] The gas chamber 12 is a space recessed from the inner peripheral surface 14A of the housing 14. The gas chamber 12 opens to the outer peripheral surface 4A of the shaft 4. The gas chamber 12 surrounds the shaft 4 in the circumferential direction. Between the gas chamber 12 and the gas-liquid chamber 11, there is a gap between the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14. This gap allows the gas chamber 12 to communicate with the gas-liquid chamber 11 around the shaft 4.

[0019] The bearing chamber 8 is a space recessed from the inner peripheral surface 14A of the housing 14. The bearing chamber 8 opens to the outer peripheral surface 4A of the shaft 4. The bearing chamber 8 circumferentially surrounds the shaft 4. Between the bearing chamber 8 and the gas chamber 12, a labyrinth 13 is present between the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14. The bearing chamber 8 communicates with the gas chamber 12 around the shaft 4. The bearing chamber 8 communicates with the gas chamber 12 via the labyrinth 13. This bearing chamber 8 is a buffer chamber into which hydrogen gas leaked from the gas chamber 12 via the labyrinth 13 flows. Note that the bearing chamber 8 is an example of a buffer chamber, and the buffer chamber is not limited to the bearing chamber 8. The buffer chamber may be any space into which hydrogen gas leaked from the gas chamber 12 via the labyrinth 13 flows.

[0020] The labyrinth 13 is located between the gas chamber 12 and the bearing chamber 8. The labyrinth 13 is a combination of many uneven gaps between the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14. In Fig. 2, the labyrinth 13 is uneven from the inner peripheral surface 14A of the housing 14, but is not limited to the unevenness shown in Fig. 2. The unevenness of the labyrinth 13 may be uneven from the outer peripheral surface 4A of the shaft 4, or may be uneven from both the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14.

[0021] The damper chamber 15 is located on the outer circumferential side of the gas-liquid chamber 11 in the radial direction of the shaft 4. The damper chamber 15 surrounds the gas-liquid chamber 11 in the circumferential direction of the shaft 4. The damper chamber 15 has a communication hole 15A. The communication hole 15A is an opening that connects the damper chamber 15 to the gas-liquid chamber 11. The opening area of ​​the communication hole 15A is smaller than the cross-sectional area of ​​the damper chamber 15 along the circumferential and axial directions of the shaft 4. The damper chamber 15 may be located on the inner circumferential side of the gas-liquid chamber 11 in the radial direction of the shaft 4. Furthermore, the damper chamber 15 may be located at a different position in the up-down direction (axial direction) relative to the position of the gas-liquid chamber 11 in the axial direction of the shaft 4.

[0022] The labyrinth 16 is located between the liquefied gas chamber 7 and the gas-liquid chamber 11. The labyrinth 16 is a combination of many uneven gaps between the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14. In Fig. 2, the labyrinth 16 is uneven from the inner peripheral surface 14A of the housing 14, but is not limited to the unevenness shown in Fig. 2. The unevenness of the labyrinth 16 may be uneven from the outer peripheral surface 4A of the shaft 4, or may be uneven from both the outer peripheral surface 4A of the shaft 4 and the inner peripheral surface 14A of the housing 14.

[0023] The heat insulating material 17 is located between the gas-liquid chamber 11 and the gas chamber 12. The heat insulating material 17 provides thermal insulation between the gas-liquid chamber 11 and the gas chamber 12.

[0024] The liquefied gas seal system 10 further includes an inlet passage 18 and an outlet passage 19. The inlet passage 18 and the outlet passage 19 each communicate with the gas chamber 12.

[0025] 3, the inlet flow passage 18 and the outlet flow passage 19 each communicate with the bearing chamber 8. That is, the inlet flow passage 18 and the outlet flow passage 19 each communicate the gas chamber 12 with the bearing chamber 8, which serves as a buffer chamber.

[0026] The liquefied gas seal system 10 further includes a control valve 20, a control valve 21, a compressor 22, a heat exchanger 23, an exhaust valve 24, and a controller 25. The control valve 20 is located in the exhaust flow path 19. The control valve 21, the compressor 22, and the heat exchanger 23 are each located in the inlet flow path 18. The exhaust valve 24 is located in a discharge flow path 26 from the bearing chamber 8, which serves as a buffer chamber. The controller 25 can control the control valve 20, the control valve 21, the compressor 22, the heat exchanger 23, and the exhaust valve 24.

[0027] The control valve 20 can adjust the differential pressure between the hydrogen gas in the gas chamber 12 and the hydrogen gas in the bearing chamber 8. The control valve 21 can adjust the flow rate and pressure of the hydrogen gas filled in the gas chamber 12. The compressor 22 can fill the gas chamber 12 with hydrogen gas from the bearing chamber 8. The heat exchanger 23 can adjust the temperature of the hydrogen gas. The exhaust valve 24 can adjust the pressure in the bearing chamber 8 and the flow rate of hydrogen gas exhausted from the bearing chamber 8.

[0028] In this liquefied gas seal system 10, the controller 25 controls the control valve 20, the control valve 21, the compressor 22, the heat exchanger 23, and the exhaust valve 24. In this way, the controller 25 controls the differential pressure between the gas chamber 12 and the bearing chamber 8. The controller 25 controls the temperature of the hydrogen gas in the gas chamber 12. The controller 25 may also control the differential pressure between the bearing chamber 8 and the exhaust flow path 26.

[0029] The liquefied gas seal system 10 includes a gas-liquid chamber 11 that communicates with the liquefied gas chamber 7, a gas chamber 12 that communicates with the gas-liquid chamber 11 and is filled with hydrogen gas (seal gas), and a labyrinth 13 that connects the gas chamber 12 to the outside of the liquefied gas chamber 7.

[0030] Hydrogen gas leaking from the gas chamber 12 is gradually depressurized as it passes through the labyrinth 13. The labyrinth 13 reduces the pressure of the hydrogen gas, thereby suppressing the amount of leaking hydrogen gas. The labyrinth 13 is suitable for suppressing the leakage of hydrogen gas in a gaseous state. However, the labyrinth 13 is less effective at suppressing the leakage of liquid hydrogen in a liquid phase than it is at suppressing the leakage of hydrogen gas.

[0031] In this liquefied gas seal system 10, liquid hydrogen flows into the gas chamber 12 via the gas-liquid chamber 11. By passing through the gas-liquid chamber 11, liquid hydrogen in a liquid phase is prevented from flowing into the gas chamber 12. Furthermore, the gas chamber 12 is filled with hydrogen gas. The liquid hydrogen that flows into the gas chamber 12 is vaporized by mixing with this hydrogen gas. This prevents liquid hydrogen in a liquid phase from reaching the labyrinth 13. This allows the labyrinth 13 to exhibit high sealing performance.

[0032] Furthermore, liquid hydrogen at a pressure lower than the critical point changes state between liquid and gas phases due to temperature changes. Liquid hydrogen at a pressure lower than the critical point may change state from gas to liquid inside the gas-liquid chamber 11 or on its way from the gas-liquid chamber 11 to the gas chamber 12. As described above, this liquefied gas seal system 10 prevents liquid hydrogen in the liquid state from reaching the labyrinth 13. This allows the labyrinth 13 to exhibit high sealing performance for liquid hydrogen at a pressure lower than the critical point. This liquefied gas seal system 10 is particularly suitable for sealing liquid hydrogen at a pressure lower than the critical point.

[0033] Furthermore, the specific gravity of liquid hydrogen is greater than the specific gravity of hydrogen gas. In this liquefied gas seal system 10, the gas chamber 12 is located above the gas-liquid chamber 11. This prevents liquid hydrogen in a liquid phase from flowing from the gas-liquid chamber 11 into the gas chamber 12. Furthermore, the labyrinth 13 is located above the gas chamber 12. This prevents liquid hydrogen from reaching the labyrinth 13. The labyrinth 13 can exhibit high sealing performance.

[0034] Furthermore, the high sealing performance of the labyrinth 13 allows the length of the labyrinth 13 to be shortened. Reducing the length of the labyrinth 13 can contribute to the miniaturization of the liquefied gas seal system 10.

[0035] This liquefied gas seal system 10 further includes a bearing chamber 8 (buffer chamber) that communicates with the gas chamber 12 via a labyrinth 13. By providing the bearing chamber 8 (buffer chamber), the liquefied gas seal system 10 can control the gas pressure and gas temperature inside the bearing chamber 8 and suppress hydrogen gas leaking from the labyrinth 13 to the bearing chamber 8 (buffer chamber). This allows the labyrinth 13 to exhibit even higher sealing performance.

[0036] The liquefied gas seal system 10 further includes a control valve 20 that adjusts the differential pressure between the gas chamber 12 and the bearing chamber 8. By adjusting the differential pressure between the gas chamber 12 and the bearing chamber 8, the liquefied gas seal system 10 can more stably suppress leakage of liquefied gas.

[0037] This liquefied gas sealing system 10 further includes a heat exchanger 23 that adjusts the gas temperature in the gas chamber 12. By adjusting the gas temperature in the gas chamber 12, the liquefied gas sealing system 10 can easily vaporize the liquefied hydrogen that has flowed into the gas chamber 12. This allows the labyrinth 13 to exhibit even higher sealing performance. In this liquefied gas sealing system 10, the amount of hydrogen gas to be filled into the gas chamber 12 is further adjusted by a control valve 21 and a compressor 22. This liquefied gas sealing system 10 can easily adjust the gas temperature in the gas chamber 12. This allows the liquefied gas sealing system 10 to vaporize the liquefied gas that has flowed into the gas chamber 12 without raising the gas temperature in the gas chamber 12 more than necessary.

[0038] The liquefied gas seal system 10 further includes a damper chamber 15 that communicates with the gas-liquid chamber 11. The damper chamber 15 suppresses changes in pressure in the gas-liquid chamber 11. In the liquefied gas turbine 1, the pressure of the liquefied hydrogen in the liquefied gas chamber 7 fluctuates. This fluctuation in the liquid hydrogen pressure causes fluctuations in the gas pressure in the gas-liquid chamber 11. The damper chamber 15 suppresses sudden fluctuations in the pressure in the gas-liquid chamber 11. This makes it easy to adjust the pressure in the gas chamber 12 that communicates with the gas-liquid chamber 11.

[0039] 2, the communication hole 15A of the damper chamber 15 communicates with the gas-liquid chamber 11 above the center in the vertical direction. The damper chamber 15 prevents liquid hydrogen from flowing in from the gas-liquid chamber 11. However, the communication hole 15A may also communicate with the gas-liquid chamber 11 below the center in the vertical direction.

[0040] Furthermore, the damper chamber 15 communicates with the gas-liquid chamber 11, but may also communicate with the gas chamber 12. The damper chamber 15 may suppress sudden fluctuations in pressure in the gas chamber 12. The damper chamber 15 may be located inside or around the gas chamber 12.

[0041] The liquefied gas seal system 10 further includes a labyrinth 16 that connects the liquefied gas chamber 7 and the gas-liquid chamber 11. This labyrinth 16 suppresses leakage of liquid hydrogen from the liquefied gas chamber 7 to the gas-liquid chamber 11. In addition, this labyrinth 16 suppresses fluctuations in the pressure of the gas-liquid chamber 11 due to fluctuations in the pressure of the liquid hydrogen in the liquefied gas chamber 7. This makes it easy to adjust the pressure in the gas chamber 12 that communicates with the gas-liquid chamber 11.

[0042] The liquefied gas seal system 10 includes a heat insulating material 17. The heat insulating material 17 is located between the gas-liquid chamber 11 and the gas chamber 12. The heat insulating material 17 reduces heat input from the gas chamber 12 to the gas-liquid chamber 11, thereby suppressing evaporation of liquid hydrogen in the gas-liquid chamber 11 and reducing leakage of liquefied gas. The heat insulating material 17 suppresses heat transfer from the gas chamber 12 to the liquefied gas chamber 7. This makes it easy to adjust the temperature of the gas chamber 12. The heat insulating material 17 may be located between the gas-liquid chamber 11 and the liquefied gas chamber 7.

[0043] The liquefied gas turbine 1 includes a turbine 2 that rotates inside a liquefied gas chamber 7, a blower 3 that rotates outside the liquefied gas chamber 7, a shaft 4 that rotates and connects the turbine 2 and the blower 3, and a liquefied gas seal system 10 that seals the liquefied gas chamber 7 around the shaft 4. In this liquefied gas turbine 1, the turbine 2, blower 3, and shaft 4 can extract energy from high-pressure liquid hydrogen while reducing the pressure of the liquid hydrogen. This liquefied gas turbine 1 can contribute to improving energy efficiency.

[0044] The liquefied gas seal system 10 includes the gas-liquid chamber 11, the gas chamber 12, and the labyrinth 13. As a result, as described above, the liquefied gas seal system 10 can suppress leakage of liquid hydrogen from the liquefied gas chamber 7.

[0045] A liquid hydrogen production system using this liquefied gas turbine 1 handles cryogenic liquid hydrogen. Cryogenic liquid hydrogen is obtained through multiple processes. Therefore, preventing leakage of cryogenic liquid hydrogen has a significant impact on the operating costs and economic efficiency of the liquid hydrogen production system. This liquefied gas turbine 1 can improve the operating costs and economic efficiency of the liquid hydrogen production system.

[0046] Although the liquefied gas seal system 10 is used in the liquefied gas turbine 1, it is not limited thereto. For example, the liquefied gas seal system 10 may be used in a power generation facility in which a generator outside the liquefied gas chamber is connected to an impeller rotating inside the liquefied gas chamber.

[0047] Here, the liquefied gas turbine 1 that obtains energy from liquid hydrogen has been described as an example. However, the use of this liquefied gas seal system 10 is not limited to the liquefied gas turbine 1. The liquefied gas seal system 10 may also be used in a pump that pressurizes liquid hydrogen. The liquefied gas seal system 10 can be widely used in turbomachines that include a shaft 4 that converts fluid energy into mechanical kinetic energy and converts mechanical kinetic energy into fluid energy.

[0048] Disclosed Aspects Each of the following aspects discloses a preferred embodiment.

[0049] [Aspect 1] A liquefied gas seal system that seals a liquefied gas chamber around a rotating shaft that penetrates from the inside to the outside of the liquefied gas chamber, the liquefied gas seal system including: a gas-liquid chamber that communicates with the liquefied gas chamber; a gas chamber that communicates with the gas-liquid chamber and is filled with a seal gas; and a labyrinth that communicates between the gas chamber and the outside of the liquefied gas chamber.

[0050] According to the above configuration, the liquefied gas passes through the gas-liquid chamber and the gas chamber and reaches the labyrinth. The liquefied gas in the liquid phase is prevented from reaching the labyrinth. This allows the labyrinth to exhibit high sealing performance. This liquefied gas seal system can reduce liquefied gas leakage.

[0051] [Aspect 2] The liquefied gas seal system according to aspect 1, further comprising a buffer chamber communicating with the gas chamber via the labyrinth.

[0052] According to the above-described configuration, it is possible to easily adjust the gas pressure and gas temperature in the buffer chamber into which the gas leaking from the labyrinth flows, thereby enabling the labyrinth to exhibit even higher sealing performance.

[0053] [Aspect 3] The liquefied gas seal system according to aspect 2, further comprising a control valve that adjusts the differential pressure between the gas chamber and the buffer chamber.

[0054] According to the above configuration, by adjusting the differential pressure between the gas chamber and the buffer chamber, the liquefied gas seal system can more stably suppress leakage of liquefied gas.

[0055] [Aspect 4] The liquefied gas seal system according to any one of Aspects 1 to 3, further comprising a heat exchanger that adjusts the gas temperature in the gas chamber.

[0056] According to the above configuration, by vaporizing the liquid hydrogen in the gas chamber, the labyrinth can exhibit even higher sealing performance.

[0057] [Aspect 5] The liquefied gas seal system according to any one of Aspects 1 to 4, further comprising a damper chamber communicating with at least one of the gas-liquid chamber and the gas chamber.

[0058] According to the above-described configuration, the damper chamber suppresses sudden pressure fluctuations, thereby facilitating pressure adjustment in the gas chamber.

[0059] [Aspect 6] The liquefied gas seal system according to any one of Aspects 1 to 5, wherein the labyrinth is a first labyrinth, and further includes a second labyrinth that connects the liquefied gas chamber and the gas-liquid chamber.

[0060] According to the above configuration, the second labyrinth suppresses sudden pressure fluctuations, making it easy to adjust the pressure in the gas chamber.

[0061] [Aspect 7] The liquefied gas seal system according to any one of Aspects 1 to 6, wherein the gas chamber is located above the gas-liquid chamber in the vertical direction, and the labyrinth is located above the gas chamber.

[0062] According to the above configuration, the liquefied gas is prevented from reaching the labyrinth, thereby enabling the labyrinth to exhibit high sealing performance.

[0063] [Aspect 8] The liquefied gas seal system according to any one of Aspects 1 to 7, further comprising a heat insulating material for insulating between the gas-liquid chamber and the gas chamber.

[0064] According to the above configuration, the heat insulating material suppresses heat transfer from the gas chamber to the liquefied gas chamber or the gas-liquid chamber, thereby facilitating temperature control of the gas chamber.

[0065] [Aspect 9] A turbomachine comprising: a first impeller rotating within a liquefied gas chamber; a second impeller rotating outside the liquefied gas chamber; a shaft rotating and connecting the first impeller and the second impeller; and a liquefied gas seal system sealing the liquefied gas chamber around the shaft, wherein the liquefied gas seal system includes: a gas-liquid chamber communicating with the liquefied gas chamber; a gas chamber communicating with the gas-liquid chamber and filled with a seal gas; and a labyrinth communicating between the gas chamber and the outside of the liquefied gas chamber.

[0066] According to the above configuration, the turbomachine can suppress leakage of liquefied gas from the liquefied gas chamber by the liquefied gas seal system, and this turbomachine can improve the operating costs and economic efficiency of the liquefied gas production device.

[0067] The liquefied gas seal system described above can be widely applied as a seal system for suppressing leakage of liquefied gas.

Claims

1. A liquefied gas seal system for sealing a liquefied gas chamber around a shaft which penetrates from the inside to the outside of the liquefied gas chamber and rotates, comprising: a gas-liquid chamber communicating with the liquefied gas chamber; a gas chamber communicating with the gas-liquid chamber and filled with a seal gas; and a labyrinth communicating between the gas chamber and the outside of the liquefied gas chamber.

2. The liquefied gas seal system according to claim 1, further comprising a buffer chamber communicating with said gas chamber via said labyrinth.

3. The liquefied gas seal system according to claim 2, further comprising a control valve for adjusting a pressure difference between said gas chamber and said buffer chamber.

4. The liquefied gas seal system according to claim 2 or 3, further comprising a heat exchanger for adjusting the gas temperature in the gas chamber.

5. A liquefied gas seal system as described in claim 1 or 2, further comprising a damper chamber communicating with at least one of the gas / liquid chamber and the gas chamber.

6. A liquefied gas seal system as claimed in claim 1 or 2, wherein the labyrinth is a first labyrinth, and further comprising a second labyrinth communicating between the liquefied gas chamber and the gas-liquid chamber.

7. A liquefied gas seal system as described in claim 1 or 2, wherein the gas chamber is located above the gas-liquid chamber in the vertical direction, and the labyrinth is located above the gas chamber.

8. A liquefied gas seal system as described in claim 1 or 2, further comprising an insulating material for insulating between the gas / liquid chamber and the gas chamber.

9. A turbomachine comprising: a first impeller rotating within a liquefied gas chamber; a second impeller rotating outside the liquefied gas chamber; a shaft rotating and connecting the first impeller and the second impeller; and a liquefied gas seal system sealing the liquefied gas chamber around the shaft, wherein the liquefied gas seal system includes: a gas-liquid chamber communicating with the liquefied gas chamber; a gas chamber communicating with the gas-liquid chamber and filled with a seal gas; and a labyrinth communicating between the gas chamber and the outside of the liquefied gas chamber.

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