Helium extraction pre-concentration device and helium extraction pre-concentration method

Abstract

The invention discloses a helium extraction pre-concentration device and a helium extraction pre-concentration method.The device comprises a first-stage heat exchanger, a rectification unit, a second-stage heat exchanger and a gas-liquid separation unit, the first-stage heat exchanger and the rectification unit are connected, and the second-stage heat exchanger and the gas-liquid separation unit are connected; the rectification unit rectifies the cooled first raw material gas to obtain first primary gas and primary liquid; the first-stage heat exchanger cools the second raw material gas to obtain second first-stage gas; the second-stage heat exchanger is used for deeply cooling the first-stage gas to obtain first-stage gas and liquid, and the gas-liquid separation unit is used for carrying out gas-liquid separation on the first-stage gas and liquid to obtain second-stage gas and second-stage liquid; and after the secondary gas is reheated for the second time, a first gas product is discharged. By means of the scheme, efficient recycling of different raw material gases can be achieved, the purity of low-purity helium obtained after pre-concentration is high, the difficulty of subsequent helium refining is lowered, the concentration capture rate of helium in the combined raw material gas is high, and efficiency improvement and emission reduction are achieved.

Description

Technical Field

[0001] This application relates to the field of helium extraction, and in particular to a helium extraction pre-concentration device and a helium extraction pre-concentration method. Background Technology

[0002] Helium, a colorless and odorless inert monatomic gas, is characterized by its difficulty in liquefaction, strong diffusivity, low solubility, and good thermal conductivity. It is widely used in aerospace, electronics industry, medical magnetic resonance imaging, low-temperature superconducting equipment, airtightness inspection of high-end equipment, and preparation of superfluid materials, and is an important strategic resource.

[0003] However, the amount of extractable helium resources on Earth is extremely small, mainly distributed in environments such as the atmosphere, water bodies, coal seams, and oil and gas reservoirs. However, it is difficult to effectively extract helium resources from the atmosphere and water bodies.

[0004] The main methods for industrial helium extraction include: helium extraction from natural gas, helium extraction from liquefied natural gas (LNG) BOG, and helium extraction through air separation. However, existing methods have relatively low helium extraction efficiency. Summary of the Invention

[0005] This application provides a helium extraction pre-concentration device and a helium extraction pre-concentration method, which can achieve efficient recovery and utilization of different raw material gases, increase efficiency and reduce emissions, and improve helium extraction efficiency.

[0006] To solve the above-mentioned technical problems, this application adopts the following technical solution: A helium extraction and pre-concentration device is provided, comprising a connected primary heat exchanger and a distillation unit. The primary heat exchanger is used to sequentially perform primary and secondary cooling treatments on a received first raw material gas. The distillation unit is used to distill the first raw material gas after the secondary cooling treatment to obtain a first primary gas and a primary liquid. The primary heat exchanger is also used to cool a received second raw material gas to obtain a second primary gas. The device further comprises a connected secondary heat exchanger and a gas-liquid separation unit. The secondary heat exchanger is used to perform deep cooling treatment on the primary gas to obtain a primary gas-liquid mixture, wherein the primary gas includes the combined first and second primary gases. The gas-liquid separation unit is used to separate the primary gas and liquid to obtain a secondary gas and a secondary liquid. The secondary heat exchanger and the primary heat exchanger are also used to perform a secondary reheat treatment on the secondary gas and discharge the first gas product.

[0007] The gas-liquid separation unit includes a gas-liquid separator, a first throttling valve, and a flash separator connected in sequence. Both the gas-liquid separator and the flash separator are connected to the secondary heat exchanger. The gas-liquid separator is used to separate the primary gas and liquid to obtain the secondary gas and sub-secondary liquid. The flash separator is used to receive the sub-secondary liquid throttled by the first throttling valve and separate it to obtain internal circulation gas and the secondary liquid. The helium extraction pre-concentration device also includes an internal circulation compressor, which is used to compress and cool the reheated internal circulation gas and then merge it into the second raw material gas to participate in the internal circulation.

[0008] The helium extraction and pre-concentration device further includes a drying unit connected to the primary heat exchanger. The drying unit is used to dehydrate the second raw material gas, and the primary heat exchanger is used to receive the dehydrated second raw material gas.

[0009] The secondary heat exchanger and the primary heat exchanger are also used to perform secondary reheating treatment on the secondary liquid to obtain the first tail gas; the helium extraction pre-concentration device also includes a heater, which is connected to the drying unit, and the heater is used to heat at least a portion of the first tail gas to obtain regeneration gas for introduction into the drying unit.

[0010] The gas-liquid separation unit includes a gas-liquid separator, a first throttling valve, and a flash separator connected in sequence. Both the gas-liquid separator and the flash separator are connected to the secondary heat exchanger. The gas-liquid separator is used to separate the primary gas and liquid to obtain the secondary gas and the sub-secondary liquid. The flash separator is used to receive the sub-secondary liquid throttled by the first throttling valve and separate it to obtain the secondary gas and the secondary liquid.

[0011] The primary heat exchanger is also used to receive the primary liquid and reheat it to obtain a second gaseous product.

[0012] The distillation unit includes a distillation column and a first evaporator-condenser. The condensation side of the first evaporator-condenser is connected to the first-stage heat exchanger, and the evaporation side of the first evaporator-condenser is connected to the bottom of the distillation column. The first evaporator-condenser is used to cool the gas after primary cooling by the first-stage heat exchanger, and then re-enters the cooled gas into the first-stage heat exchanger for secondary cooling. The primary liquid obtained at the bottom of the distillation column is used as the cold source for the first evaporator-condenser.

[0013] The helium pre-concentration device further includes an external circulation device, which includes an external circulation compressor and an expander connected to a primary heat exchanger. The external circulation compressor is used to compress and cool the external circulation gas. The primary heat exchanger is used to cool the external circulation gas compressed and cooled by the external circulation compressor. The expander is used to expand and refrigerate the external circulation gas after it has been cooled by the primary heat exchanger. The primary heat exchanger is also used to reheat the external circulation gas after it has been expanded and refrigerated and then pass it into the external circulation compressor.

[0014] The helium pre-concentration device further includes a second evaporator-condenser and a second throttling valve connected in sequence. The first-stage heat exchanger is used to liquefy the external circulating gas compressed and cooled by the external circulating compressor to obtain a tertiary liquid. The second throttling valve is used to throttle the tertiary liquid and then pass it into the evaporator side of the second evaporator-condenser for evaporation to obtain a tertiary gas. The first-stage heat exchanger is used to reheat the tertiary gas after evaporation and integrate it into the external circulating compressor. The condensation side of the second evaporator-condenser is connected to the top of the distillation column, and the tertiary liquid is used as a cold source for the second evaporator-condenser.

[0015] Wherein, the first raw material gas includes liquefied natural gas flash vapor; and / or, the second raw material gas includes nitrogen, helium, hydrogen and moisture.

[0016] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a helium extraction and pre-concentration method, comprising: a first raw material gas being sequentially passed through a primary heat exchanger and a secondary heat exchanger for primary cooling and secondary cooling treatment; the first raw material gas after the secondary cooling treatment being passed through the distillation unit for distillation treatment to obtain a first primary gas and a primary liquid; and a second raw material gas being passed through the primary heat exchanger for cooling to obtain a second primary gas; The first-stage gas and the second-stage gas are combined to form a first-stage gas. The first-stage gas is passed into the second-stage heat exchanger for deep cooling to obtain a first-stage gas-liquid mixture. The first-stage gas-liquid mixture is passed into a gas-liquid separation unit for gas-liquid separation to obtain a second-stage gas and a second-stage liquid. The second-stage gas is passed into the second-stage heat exchanger and the first-stage heat exchanger in sequence for secondary reheating and then discharged as the first gas product.

[0017] The beneficial effects of this application are as follows: Unlike existing technologies, the helium extraction pre-concentration device and method of this application use two raw material gases as raw materials and employ deep freezing to pre-concentrate the raw material gases to obtain low-purity helium gas required for helium refining. The low-purity helium gas obtained after pre-concentration has high purity, reducing the difficulty of subsequent helium refining. The helium extraction pre-concentration device of this application performs joint pre-concentration treatment on two raw material gases, enabling efficient recovery and utilization of different raw material gases. The capture rate of helium concentration in the combined raw material gas reaches 99%, achieving increased efficiency and emission reduction. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the helium pre-concentration device of this application; Figure 2 This is a schematic diagram of another embodiment of the helium pre-concentration device of this application; Figure 3 This is a flowchart illustrating one embodiment of the helium pre-concentration method of this application.

[0019] Reference numerals: 1. Helium pre-concentration unit; 10. Primary heat exchanger; 11. Secondary heat exchanger; 20. Distillation unit; 21. Distillation column; 22. First evaporator-condenser; 22a. Condensation side of the first evaporator-condenser; 22b. Evaporation side of the first evaporator-condenser; 30. Gas-liquid separation unit; 31. Gas-liquid separator; 32. First throttle valve; 33. Flash separator; 40. External circulation unit; 41. External circulation compressor; 42. Expander; 43. Third throttle valve; 44. Second throttle valve; 45. Second evaporator-condenser; 45a. Condensation side of the second evaporator-condenser; 45b. Evaporation side of the second evaporator-condenser; 50. Dry... Drying unit; 51, heater; 60, internal circulation compressor; 100, first raw material gas; 200, second raw material gas; 203, second primary gas; 301, primary liquid; 302, second gas product; 401, first primary gas; 402, primary gas; 403, primary gas-liquid mixture; 404, secondary gas; 406, first gas product; 411, secondary liquid; 413, internal circulation gas; 421, secondary liquid; 424, first tail gas; 426, regenerated gas; 500, external circulation gas replenishment port; 501, external circulation gas; 512, tertiary liquid; 514, tertiary gas; 600, external circulation gas liquid replenishment port. Detailed Implementation

[0020] To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following detailed description is provided with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] See Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the helium extraction pre-concentration apparatus of this application. The arrows in the diagram indicate the flow direction of the fluid. The helium extraction pre-concentration apparatus 1 includes a connected primary heat exchanger 10 and a distillation unit 20. The primary heat exchanger 10 is used to sequentially perform primary and secondary cooling treatments on the received first raw material gas 100. The distillation unit 20 is used to distill the first raw material gas 100 after the secondary cooling treatment to obtain a first primary gas 401 and a first primary liquid 301. Specifically, the first feed gas 100 can be liquefied natural gas flash vapor (LNG-BOG). The first feed gas 100 is first passed into the first-stage heat exchanger 10 for primary cooling. After being cooled to a certain temperature, it returns to the first-stage heat exchanger 10 for secondary cooling. The deeply cooled first feed gas 100 enters the distillation unit 20 to participate in distillation. Through distillation, a primary liquid 301 with a higher boiling point and a first primary gas 401 with a lower boiling point are separated. The primary liquid 301 is liquid methane, which is extracted from the bottom of the distillation unit 20. The first primary gas 401 is helium-rich gas, which is obtained from the top of the distillation unit 20.

[0022] The primary heat exchanger 10 is also used to cool the received second raw material gas 200 to obtain a second primary gas 203. The helium extraction pre-concentration device 1 also includes a connected secondary heat exchanger 11 and a gas-liquid separation unit 30. The secondary heat exchanger 11 is used to deeply cool the primary gas 402 to obtain a primary gas-liquid 403. The primary gas 402 includes a combined first primary gas 401 and a second primary gas 203. The gas-liquid separation unit 30 is used to separate the primary gas-liquid 403 to obtain a secondary gas 404 and a secondary liquid 421. Specifically, the second raw material gas 200 can be a helium-containing chemical tail gas feedstock emitted from a chemical process, including nitrogen, helium, hydrogen, and moisture. The second raw material gas 200 is first passed into the primary heat exchanger 10 for cooling. After cooling to a certain temperature, it becomes the second primary gas 203. The second primary gas 203 merges with the aforementioned first primary gas 401 (i.e., helium-rich gas) to form primary gas 402. This primary gas 402 is then passed into the secondary heat exchanger 11 for deep cooling. After deep cooling, the primary gas 402 is cooled and partially liquefied to obtain primary gas-liquid 403, which is then passed into the gas-liquid separation unit 30. The gas-liquid separation unit 30 separates the primary gas-liquid 403 to obtain secondary gas 404 and secondary liquid 421. Helium, which has the lowest boiling point, remains in the gas phase, while the secondary gas 404 has a higher helium content.

[0023] The secondary heat exchanger 11 and the primary heat exchanger 10 are also used to perform a secondary reheating treatment on the secondary gas 404 and discharge the first gas product 406. After the secondary gas 404 returns to the secondary heat exchanger 11 for reheating to a certain temperature, it enters the primary heat exchanger 10 for further reheating to room temperature to obtain the first gas product 406. This first gas product 406 is low-purity helium. Compared with the first raw material gas 100 and the second raw material gas 200, the purity of the helium is improved, and it can be sent to the helium refining system.

[0024] This application uses two feedstock gases as raw materials and employs a deep freezing method to pre-concentrate the feedstock gases to obtain low-purity helium required for helium refining. The low-purity helium obtained after pre-concentration has high purity, reducing the difficulty of subsequent helium refining. The helium extraction pre-concentration device 1 of this application performs joint pre-concentration treatment on the two feedstock gases, enabling efficient recovery and utilization of different feedstock gases, and achieving a high concentration and capture rate of helium in the combined feedstock gas, thus achieving efficiency improvement and emission reduction.

[0025] Optionally, continue reading Figure 1In one embodiment, the helium pre-concentration device 1 further includes an external circulation device 40, which includes an external circulation compressor 41 and an expander 42 connected to the primary heat exchanger 10. The external circulation compressor 41 is used to compress and cool the external circulation gas 501. The primary heat exchanger 10 is used to cool the external circulation gas 501 that has been compressed and cooled by the external circulation compressor 41. The expander 42 is used to expand and refrigerate the external circulation gas 501 that has been cooled by the primary heat exchanger 10. The primary heat exchanger 10 is also used to reheat the external circulation gas 501 that has been expanded and refrigerated and then pass it into the external circulation compressor 41. Specifically, the external circulating gas 501 can be nitrogen or air, preferably nitrogen. The external circulating gas 501 is supplied from outside the device. It is first compressed and cooled by the external circulating compressor 41. After compression and cooling, the external circulating gas 501 is cooled again by the primary heat exchanger 10 before entering the expander 42. After expansion and refrigeration by the expander 42, it returns to the primary heat exchanger 10, is reheated to room temperature, and merges back into the external circulating gas 501, allowing it to re-enter the external circulating compressor 41, forming an external circulating loop. This external circulating loop provides energy to the helium pre-concentration unit 1 and is relatively independent of other loops, resulting in a simple process. Optionally, the external circulating device 40 also includes a third throttle valve 43. A portion of the external circulating gas 501 that has been cooled again by the primary heat exchanger 10 passes through the third throttle valve 43, bypasses the expander 42, and directly merges into the external circulating gas 501 that has been expanded by the expander 42.

[0026] Optionally, continue reading Figure 1 In one embodiment, the helium pre-concentration device 1 further includes a drying unit 50, which is connected to a primary heat exchanger 10. The drying unit 50 is used to dehydrate the second raw material gas 200, and the primary heat exchanger 10 is used to receive the dehydrated second raw material gas 200. The second raw material gas 200 enters the primary heat exchanger 10 for cooling after being dehydrated by the drying unit 50.

[0027] Optionally, continue reading Figure 1In one embodiment, the secondary heat exchanger 11 and the primary heat exchanger 10 are further used to perform a secondary reheating treatment on the secondary liquid 421 to obtain the first tail gas 424. Specifically, the gas-liquid separation unit 30 separates the primary gas-liquid 403 to obtain a secondary gas 404 and a secondary liquid 421. The secondary liquid 421 is a helium-free liquid, which is first vaporized in the secondary heat exchanger 11 and reheated to a certain temperature, and then further reheated to room temperature in the primary heat exchanger 10 to obtain the first tail gas 424, which includes nitrogen. The helium extraction pre-concentration device 1 also includes a heater 51, which is connected to the drying unit 50. The heater 51 is used to heat at least a portion of the first tail gas 424 to obtain a regeneration gas 426 for introduction into the drying unit 50. Specifically, a portion of the first exhaust gas 424 can be introduced into the drying unit 50 as regeneration gas for drying the adsorbent, desorbing impurities adsorbed on the adsorbent and thereby restoring the adsorbent's adsorption capacity. This application enables the effective utilization of the pre-concentrated exhaust gas. In other embodiments, the regeneration gas 426 may not be extracted from the first exhaust gas 424, but may be supplied separately.

[0028] Optionally, continue reading Figure 1 In one embodiment, the gas-liquid separation unit 30 includes a gas-liquid separator 31, a first throttling valve 32, and a flash separator 33 connected in sequence. Both the gas-liquid separator 31 and the flash separator 33 are connected to the secondary heat exchanger 11. The gas-liquid separator 31 is used to separate the primary gas-liquid 403 to obtain a secondary gas 404 and a sub-secondary liquid 411. The flash separator 33 is used to receive the sub-secondary liquid 411 throttled by the first throttling valve 32 and separate it to obtain an internal circulation gas 413 and a secondary liquid 421. The helium pre-concentration device 1 also includes an internal circulation compressor 60, which is used to compress and cool the reheated internal circulation gas 413 before it is incorporated into the second raw material gas 200 for internal circulation.

[0029] Specifically, in this embodiment, the gas-liquid separation unit 30 is a two-stage separation device. The primary gas-liquid 403, after being deeply cooled by the secondary heat exchanger 11, first enters the gas-liquid separator 31 for the first gas-liquid separation to obtain a secondary gas 404 and a sub-secondary liquid 411. The secondary gas 404 obtained from the first gas-liquid separation in the gas-liquid separator 31 includes helium and hydrogen with low boiling points, and the sub-secondary liquid 411 includes liquid nitrogen with high boiling points, as well as a small amount of incompletely separated liquid helium and liquid hydrogen. The gas phase secondary gas 404 is returned to the secondary heat exchanger 11 and the primary heat exchanger 10 for reheating. As mentioned above, this portion of secondary gas 404 is discharged as the first gas product 406. The liquid phase sub-secondary liquid 411 is throttled by the first throttle valve 32 and then fed into the flash separator 33 for a second gas-liquid separation. After the flash separator 33 depressurizes the pressure, it lowers the boiling point of the sub-secondary liquid 411, further separating the residual helium and hydrogen with lower boiling points. This portion of gas is then continuously reheated to room temperature by the secondary heat exchanger 11 and the primary heat exchanger 10 and then fed into the internal circulation compressor 60 as internal circulation gas 413. The internal circulation compressor 60 compresses and cools the internal circulation gas 413. Since the internal circulation gas 413 contains helium, when the internal circulation gas 413 merges into the second raw material gas 200, it is used as a raw material gas again to participate in the next purification, forming an internal circulation loop. This internal circulation loop can ensure the capture rate and purity of helium and greatly reduce the loss of helium.

[0030] Optionally, see Figure 2 In another embodiment, the gas-liquid separation unit 30 includes only a gas-liquid separator 31, and the helium pre-concentration device 1 does not include an internal circulation compressor 60. In this embodiment, the gas-liquid separator 31 is used to separate the primary gas-liquid 403 to obtain a secondary gas 404 and a secondary liquid 421. The secondary gas 404 is returned to the secondary heat exchanger 11 and the primary heat exchanger 10 for two reheating cycles. After reheating to room temperature, the first gas product 406 is directly obtained. In this embodiment, the helium pre-concentration device 1 obtains low-purity helium through only one gas-liquid separation and does not include an internal circulation loop.

[0031] Optionally, continue reading Figure 1The primary heat exchanger 10 is also used to receive the primary liquid 301 and reheat it to obtain the second gaseous product 302. Specifically, the primary liquid 301, i.e., liquid methane, obtained from the bottom of the distillation unit 20 can be reheated in the primary heat exchanger 10 to obtain the second gaseous product 302, i.e., methane gas. This second gaseous product 302 can be directly sold. At the same time, the liquid methane entering the primary heat exchanger 10 can provide cooling capacity for the primary heat exchanger 10, used to cool the first feed gas 100 and the second feed gas 200. In other embodiments, the primary liquid 301 may also be sent out directly as a liquid product without reheating in the primary heat exchanger 10. In this case, in order to ensure that the helium extraction pre-concentration device 1 has sufficient energy, the supply of external circulating gas 501 should be increased.

[0032] Optionally, continue reading Figure 1 The distillation unit 20 includes a distillation column 21 and a first evaporator-condenser 22. The condensation side 22a of the first evaporator-condenser 22 is connected to the first-stage heat exchanger 10, and the evaporation side 22b of the first evaporator-condenser 22 is connected to the bottom of the distillation column 21. The first evaporator-condenser 22 is used to cool the gas after primary cooling treatment by the first-stage heat exchanger 10, and to pass the cooled gas back into the first-stage heat exchanger 10 for secondary cooling treatment. The primary liquid 301 obtained at the bottom of the distillation column 21 is used as the cold source of the first evaporator-condenser 22. Specifically, the first feed gas 100, after undergoing primary cooling in the first heat exchanger 10, is introduced into the condensation side of the first evaporator-condenser 22. After being cooled by the condensation side 22a of the first evaporator-condenser 22, the first feed gas 100 undergoes secondary cooling in the first heat exchanger 10. Thus, after undergoing three cooling processes, the first feed gas 100 is introduced into the lower part of the distillation column 21 for distillation. At the bottom of the distillation column 21, i.e., the evaporation side 22b of the first evaporator-condenser 22, a primary liquid 301 is obtained. This primary liquid 301 serves as a cold source for the first evaporator-condenser 22, cooling the first feed gas 100 that has passed through the condensation side 22a. Meanwhile, primary gas 402 is obtained at the top of the distillation column 21.

[0033] Optionally, continue reading Figure 1The helium pre-concentration device 1 also includes a second evaporator-condenser 45 and a second throttle valve 44 connected in sequence; a first-stage heat exchanger 10 is used to liquefy the external circulating gas 501 compressed and cooled by the external circulating compressor 41 to obtain a third-stage liquid 512; the second throttle valve 44 is used to throttle the third-stage liquid 512 and then pass it into the evaporation side 45b of the second evaporator-condenser 45 for evaporation to obtain a third-stage gas 514; the first-stage heat exchanger 10 is used to reheat the evaporated third-stage gas 514 and integrate it into the external circulating compressor 41; the condensation side 45a of the second evaporator-condenser 45 is connected to the top of the distillation column 21, and the third-stage liquid 512 is used as a cold source for the second evaporator-condenser 45. Specifically, after being compressed and cooled by the external circulation compressor 41, part of the external circulation gas 501 enters the external circulation loop, while the other part enters the first-stage heat exchanger 10 for deep cooling and liquefaction to obtain tertiary liquid 512. The tertiary liquid 512 is then throttled by the second throttling valve 44 and fed into the evaporation side 45b of the second evaporator-condenser 45, providing a continuous cold source for the condensation side 45a of the second evaporator-condenser 45, i.e., the top of the distillation column 21, ensuring continuous distillation processing in the distillation column 21. The tertiary liquid 512 is evaporated into tertiary gas 514 via the evaporation side 45b of the second evaporator-condenser 45. The tertiary gas 514 is reheated to room temperature by the first-stage heat exchanger 10 and then merged into the external circulation gas 501, both flowing into the external circulation compressor 41. Optionally, the unevaporated portion of the tertiary liquid 512 (shown as 601 in the figure) can also be directly fed into the first-stage heat exchanger 10 for reheating to room temperature before merging into the external circulation gas 501 and flowing into the external circulation compressor 41.

[0034] Optionally, continue reading Figure 1 The helium pre-concentration device 1 also includes an external circulation gas replenishment port 500 connected to the external circulation compressor 41, which is used to replenish the small amount of external circulation gas 501 lost due to mechanical leakage, etc.

[0035] Optionally, continue reading Figure 1 The helium pre-concentration unit 1 also includes an external circulation gas replenishment port 600 connected to the evaporation side of the second evaporator condenser 45, which is used to quickly cool down the unit during hot start-up to accelerate the start-up speed or to replenish the unit with cooling capacity when the expander 42 temporarily fails, so as to maintain the unit's continued operation.

[0036] See Figure 3 This application also provides a helium extraction pre-enrichment method, which includes the following steps: S100: The first raw material gas is sequentially fed into the first-stage heat exchanger and the second-stage heat exchanger for primary and secondary cooling treatment.

[0037] S200: The first raw material gas after secondary cooling is fed into the distillation unit for distillation to obtain the first stage gas and the first stage liquid.

[0038] S300: The second raw material gas is introduced into the first-stage heat exchanger for cooling and to obtain the second-stage gas.

[0039] S400: The first-stage gas and the second-stage gas are combined to form the first-stage gas. The first-stage gas is then passed into the second-stage heat exchanger for deep cooling to obtain the first-stage gas-liquid mixture.

[0040] S500: The primary gas-liquid mixture is fed into the gas-liquid separation unit for gas-liquid separation to obtain secondary gas and secondary liquid; optionally, the primary gas-liquid mixture is fed into the gas-liquid separation unit for gas-liquid separation to obtain internal circulating gas, which is then fed into the secondary heat exchanger and the primary heat exchanger for secondary reheating, and then pressurized by the internal circulating compressor and fed into the second raw material gas.

[0041] S600: The secondary gas is sequentially passed through the secondary heat exchanger and the primary heat exchanger for secondary reheating treatment, and the first gas product is discharged. The above steps can be referred to the helium pre-concentration unit 1 mentioned above, and will not be repeated here.

[0042] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A helium lift pre-concentrator, comprising: Comprise: a connected primary heat exchanger and a rectification unit, the primary heat exchanger is used for sequentially performing a primary cooling treatment and a secondary cooling treatment on a received first raw gas, and the rectification unit is used for performing a rectification treatment on the first raw gas after the secondary cooling treatment and obtaining a first primary gas and a primary liquid; the primary heat exchanger is also used for performing a cooling treatment on a received second raw gas and obtaining a second primary gas; a connected secondary heat exchanger and a gas-liquid separation unit, the secondary heat exchanger is used for performing a deep cooling treatment on a primary gas to obtain a primary gas-liquid, wherein the primary gas comprises the first primary gas and the second primary gas, and the gas-liquid separation unit is used for performing a gas-liquid separation on the primary gas-liquid to obtain a secondary gas and a secondary liquid; The secondary heat exchanger and the primary heat exchanger are also used for performing a secondary reheat treatment on the secondary gas and discharging a first gas product.

2. The helium extraction and pre-concentration device according to claim 1, wherein The gas-liquid separation unit comprises a gas-liquid separator, a first throttle valve and a flash separator connected in sequence, and the gas-liquid separator and the flash separator are connected with the secondary heat exchanger, wherein the gas-liquid separator is used for performing a gas-liquid separation on the primary gas-liquid to obtain the secondary gas and a sub-secondary liquid, and the flash separator is used for receiving the sub-secondary liquid throttled by the first throttle valve and separating to obtain an internal circulation gas and the secondary liquid; The helium extraction and pre-concentration device further comprises an internal circulation compressor, which is used for compressing and cooling the reheat internal circulation gas and then merging into the second raw gas for internal circulation.

3. The helium pre-concentration device of claim 1, wherein, The helium extraction and pre-concentration device further comprises: a drying unit connected with the primary heat exchanger, the drying unit is used for performing a dehydration treatment on the second raw gas, and the primary heat exchanger is used for receiving the second raw gas after the dehydration treatment.

4. The helium extraction and pre-concentration device according to claim 3, wherein The secondary heat exchanger and the primary heat exchanger are also used for performing a secondary reheat treatment on the secondary liquid and obtaining a first tail gas; The helium extraction and pre-concentration device further comprises a heater connected with the drying unit, the heater is used for heating at least part of the first tail gas to obtain a regeneration gas for entering the drying unit.

5. The helium extraction and pre-concentration device according to claim 1, wherein The primary heat exchanger is also used for receiving the primary liquid and performing a reheat treatment to obtain a second gas product.

6. The helium extraction and pre-concentration device according to claim 1, wherein The rectification unit comprises a rectification tower and a first evaporation condenser, a condensing side of the first evaporation condenser is connected with the primary heat exchanger, and an evaporation side of the first evaporation condenser is connected with a bottom of the rectification tower; The first evaporation condenser is used for cooling the gas after the first cooling treatment by the primary heat exchanger, and the gas after the cooling treatment is introduced into the primary heat exchanger again for secondary cooling treatment; the primary liquid obtained from the bottom of the rectifying tower is used as the cold source of the first evaporation condenser.

7. The helium pre-concentration device of claim 2, wherein, The helium extraction pre-concentration device further comprises: The outer circulation device comprises an outer circulation compressor and an expander connected with the primary heat exchanger respectively, the outer circulation compressor is used for compressing and cooling the outer circulation gas, the primary heat exchanger is used for cooling the outer circulation gas compressed and cooled by the outer circulation compressor, the expander is used for expanding the outer circulation gas cooled by the primary heat exchanger for refrigeration treatment, and the primary heat exchanger is further used for reheating the outer circulation gas after the refrigeration treatment and introducing it into the outer circulation compressor.

8. A helium pre-concentration device according to claim 7, wherein The helium extraction pre-concentration device further comprises a second evaporation condenser and a second throttling valve connected in sequence; The primary heat exchanger is used for liquefying the outer circulation gas compressed and cooled by the outer circulation compressor to obtain tertiary liquid, the second throttling valve is used for throttling the tertiary liquid and introducing it into the evaporation side of the second evaporation condenser for evaporation treatment to obtain tertiary gas, and the primary heat exchanger is used for reheating the tertiary gas after the evaporation treatment and introducing it into the outer circulation compressor; the condensing side of the second evaporation condenser is connected with the top of the rectifying tower, and the tertiary liquid is used as the cold source of the second evaporation condenser.

9. The helium extraction pre-concentration device according to any one of claims 1-8, wherein, The first raw gas comprises liquefied natural gas flash gas; and / or, The second raw gas comprises nitrogen, helium, hydrogen and moisture.

10. A helium extraction pre-concentration method, comprising the steps of: a first raw gas is introduced into a primary heat exchanger and a secondary heat exchanger in sequence for primary cooling treatment and secondary cooling treatment; the first raw gas after the secondary cooling treatment is introduced into the rectifying unit for rectification treatment to obtain a first primary gas and a primary liquid; a second raw gas is introduced into a primary heat exchanger for cooling treatment to obtain a second primary gas; the first primary gas and the second primary gas are combined to form a primary gas, and the primary gas is introduced into the secondary heat exchanger for deep cooling treatment to obtain a primary gas-liquid; the primary gas-liquid is introduced into a gas-liquid separation unit for gas-liquid separation to obtain a secondary gas and a secondary liquid; the secondary gas is introduced into a secondary heat exchanger and a primary heat exchanger in sequence for secondary reheating treatment, and a first gas product is discharged.

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