Integrated natural gas wellhead helium extraction system

Abstract

The utility model provides an integrated natural gas wellhead helium extraction system, relates to the technical field of natural gas extraction, and solves the technical problems that the existing shale gas wellhead helium extraction recovery rate is low, and the oxygen content, the neon content and the nitrogen content in crude helium after membrane separation are high. The device comprises a membrane separation system for extracting crude helium, and further comprises a cryogenic adsorption system for removing nitrogen and neon, the membrane separation system comprises multiple stages of membrane separation assemblies which are communicated in sequence, and return pipelines for circulating return are arranged among the membrane separation assemblies. According to the utility model, after multi-stage membrane separation, purification is carried out through the purification device, and nitrogen and neon are removed through the cryogenic adsorption system, helium with the concentration reaching 99.999% can be obtained; and the retentate gas is recovered to the previous stage or raw material gas, so that the helium recovery rate is fully improved.

Description

Technical Field

[0001] The utility model relates to the technical field of natural gas extraction, and particularly relates to an integrated natural gas wellhead helium extraction system. Background Technique

[0002] Helium is a rare strategic resource. At room temperature and atmospheric pressure, helium is colorless, odorless, non-toxic, chemically inert, has a small density, good thermal conductivity, and strong diffusivity; while liquid helium has special properties such as λ-transition, no triple point, high quantum mechanical zero-point energy, and low latent heat of vaporization. Therefore, helium gas and liquid helium have been widely used in fields such as space exploration, military industry, superconductivity, protective gas, leak detection, and nuclear industry. Helium is mainly extracted from natural gas.

[0003] Natural gas helium extraction technologies include non-cryogenic methods and cryogenic methods (cryogenic refrigeration method). Non-cryogenic methods mainly include physical adsorption method, solvent absorption method, membrane separation method, and pressure swing adsorption method (PSA method), and the cryogenic method is the condensation method.

[0004] Although the helium recovery rate of helium extraction by the cryogenic refrigeration method is usually high (94%), to produce 1 m 3 of helium by the cryogenic refrigeration method, nearly 600 m 3 of natural gas needs to be processed, with high production costs, large equipment investment, high energy consumption, and poor cold insulation effect. In order to improve the economy of helium extraction, the cryogenic refrigeration method is combined with other helium extraction methods or other separation processes for combined or co-production helium extraction. The combination of the cryogenic refrigeration method and the membrane separation method for helium extraction has significantly reduced energy consumption and equipment investment costs.

[0005] For example, a system and method for extracting helium from natural gas or BOG proposed in the patent with the publication number of CN113501508A, by adopting methods such as membrane separation treatment, catalytic dehydrogenation treatment, and purification treatment, the processing volume of the mixed gas of the equipment after the membrane separation system is small, reducing equipment investment and production costs. However, on the basis of reducing equipment investment in the above treatment, the membrane separation mainly removes methane among them. Neon is a rare inert gas, and pressure swing adsorption (PSA) cannot adsorb neon. Therefore, the neon content in the helium gas finally separated after multi-stage concentration and enrichment is still relatively high, resulting in a relatively low purity of the finally obtained helium gas; and its membrane separation system only includes two-stage membrane modules for separation, which is mainly used to remove most of the methane and is not applicable to the case of complex composition of wellhead natural gas without any treatment, and the processing efficiency is low. Content of the Utility Model

[0006] The purpose of the utility model is to provide an integrated natural gas wellhead helium extraction system to solve the technical problems of relatively low helium recovery rate at the existing shale gas wellhead, and relatively high oxygen content, neon content, and nitrogen content in the crude helium gas after membrane separation.

[0007] The embodiments of the utility model are achieved by the following technical solutions:

[0008] An integrated natural gas wellhead helium extraction system includes a membrane separation system for extracting crude helium and a cryogenic adsorption system for nitrogen and neon removal; the membrane separation system includes a multi-stage membrane separation component connected in sequence, and a reflux pipeline for circulating and refluxing is arranged between the membrane separation components.

[0009] Preferably, the membrane separation component includes a separation tank, an enrichment membrane for helium permeation measurement is arranged at both ends of the separation tank, and a retentate membrane for discharging the retentate gas is arranged, and the enrichment side in the middle section of the separation tank is connected in sequence with the permeation side of the lower-stage separation tank.

[0010] Preferably, the membrane separation system includes a first-stage membrane separation component, a second-stage membrane separation component, a third-stage membrane separation component, and a fourth-stage membrane separation component connected in sequence.

[0011] Preferably, the reflux pipeline includes a first reflux pipe fitting for recycling the retentate gas of the second-stage membrane separation component to the second-stage membrane separation component, a second reflux pipe fitting for recycling the retentate gas of the third-stage membrane separation component to the second-stage membrane separation component, and a third reflux pipe fitting for recycling the retentate gas of the fourth-stage membrane separation component to the third-stage membrane separation component.

[0012] Preferably, the second-stage membrane separation component includes a first-stage separation membrane connected to the enrichment side of the first-stage membrane separation component and a second-stage separation membrane connected to the retentate side of the first-stage membrane separation component, and the enrichment side of the second-stage separation membrane is connected to the permeation side of the first-stage separation membrane through the first reflux pipe fitting.

[0013] Preferably, the membrane separation system further includes a compressor system for compressing gas to provide permeation power, and the compressor system includes a first compressor for introducing natural gas into the second-stage membrane separation component, a second compressor for introducing natural gas into the third-stage membrane separation component, a third compressor for introducing natural gas into the fourth-stage membrane separation component, and a fourth compressor for introducing natural gas into the subsequent treatment system.

[0014] Preferably, it further includes a pretreatment system for pre-treating natural gas before entering the membrane and a purification device for purifying the natural gas after membrane permeation treatment.

[0015] Preferably, the cryogenic adsorption system includes a helium purifier for nitrogen removal and a neon removal cold box for neon removal.

[0016] By adopting the technical solution, impurity gases in natural gas can be fully separated by the membrane separation system, and helium can be enriched. After multi-stage membrane separation, helium can be purified to 40%. After purification by the purification device and nitrogen and neon removal by the cryogenic adsorption system, helium with a concentration of 99.999% can be easily obtained;

[0017] The membrane separation system fully recovers the retentate gas, gradually enriches the helium gas on the enrichment side in the separation tank, and the retentate gas on the retentate side passes through the reflux pipeline to recover the retentate gas to the previous stage or the raw material gas. At a certain stage of the membrane separation module, two sets of separation membranes are arranged at both ends, namely two sets of separation tanks. The enrichment side of the first-stage separation membrane is introduced into the next-stage membrane separation system, and the retentate gas on the retentate side of the first-stage separation membrane is introduced into the second-stage separation membrane for further enrichment. The helium gas on the enrichment side of the second-stage separation membrane is recovered to the first-stage separation membrane, while the retentate gas of the second-stage separation membrane is not recovered but discharged, ensuring that on the basis of fully recycling the retentate gas, the impurity gas content of the raw material gas will not become higher and higher, and further ensuring the purity of helium gas.

[0018] The technical solution of the embodiment of the present utility model has at least the following advantages and beneficial effects:

[0019] 1. The present utility model fully separates the impurity gas in natural gas through the membrane separation system, enriches helium gas. After multi-stage membrane separation, and then purified by a purification device, and nitrogen and neon are removed by a cryogenic adsorption system, helium gas with a concentration of up to 99.999% can be obtained;

[0020] 2. The membrane separation system of the present utility model fully recovers the retentate gas, gradually enriches the helium gas on the enrichment side in the separation tank, and the retentate gas on the retentate side passes through the reflux pipeline to recover the retentate gas to the previous stage or the raw material gas, fully improving the helium gas recovery rate;

[0021] 3. The retentate gas of the second-stage separation membrane of the present utility model is not recovered but discharged, ensuring that on the basis of fully recycling the retentate gas, the impurity gas content of the raw material gas will not become higher and higher, and further ensuring the purity of helium gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the embodiment of the present utility model, the following will briefly introduce the drawings required to be used in the embodiment. It should be understood that the following drawings only show some embodiments of the present utility model, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of the overall structure of an integrated natural gas wellhead helium extraction system provided in Embodiment 1 of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of the membrane separation system of an integrated natural gas wellhead helium extraction system provided in Embodiment 2 of the present invention;

[0025] Figure 3 It is a schematic diagram of the structure of the membrane separation system of an integrated natural gas wellhead helium extraction system provided in Embodiment 3 of the present invention;

[0026] Icons: 1. Membrane separation system; 11. Primary membrane separation module; 12. Secondary membrane separation module; 121. First-stage separation membrane; 122. Second-stage separation membrane; 13. Tertiary membrane separation module; 14. Quaternary membrane separation module; 15. Quinary membrane separation module; 2. Purification device; 3. Cryogenic adsorption system; 51. First compressor; 52. Second compressor; 53. Third compressor; 54. Fourth compressor; 61. First reflux pipe fitting; 62. Second reflux pipe fitting; 63. Third reflux pipe fitting; 7. Pretreatment system. Detailed implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Components of the embodiments of the present utility model described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present utility model provided in the accompanying drawings is not intended to limit the scope of the claimed present utility model, but merely represents selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0029] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0030] In the description of the present utility model, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the accompanying drawings or the orientation or positional relationship in which the product of this application is usually placed during use. This is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present utility model.

[0031] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and defined, if the terms "set", "installed", "connected", "connected" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0032] Embodiment 1

[0033] An integrated natural gas wellhead helium extraction system includes a membrane separation system 1 for extracting crude helium, and also includes a cryogenic adsorption system 3 for nitrogen removal and neon removal; the membrane separation system 1 includes a multi-stage membrane separation component connected in sequence, and a reflux pipeline for circulating and refluxing is provided between the membrane separation components.

[0034] In this embodiment, the membrane separation component includes a separation tank, an enrichment membrane for helium measurement by permeation is provided at both ends of the separation tank, and a retentate membrane for discharging the retentate gas is provided, and the enrichment side in the middle section of the separation tank is connected in sequence to the permeation side of the lower-level separation tank.

[0035] In this embodiment, it also includes a pretreatment system 7 for pre-treating natural gas before entering the membrane and a purification device 2 for purifying natural gas after membrane permeation treatment;

[0036] The pretreatment device 7 is used to dehydrate, deoil, desulfurize and remove carbon dioxide from natural gas;

[0037] Glycol dehydration device is used for dehydration; activated carbon adsorption is used for deoiling and desulfurization; amine-based solution is used to absorb carbon dioxide.

[0038] In this embodiment, the cryogenic adsorption system 3 includes a helium purifier for nitrogen removal and a neon removal cold box for neon removal.

[0039] Working principle and usage method:

[0040] By adopting this technical solution, the impurity gas in natural gas can be fully separated by the membrane separation system 1, and helium can be enriched. After multi-stage membrane separation, helium can be purified to 40%. After purification by the purification device 2 and nitrogen and neon removal by the cryogenic adsorption system 3, helium with a concentration of 99.999% can be easily obtained;

[0041] The membrane separation system 1 fully recovers the retentate gas, gradually enriches the helium gas on the enrichment side in the separation tank, and the retentate gas on the retentate side is recycled to the previous stage or the raw material gas through the reflux pipeline. At a certain stage of the membrane separation module, two sets of separation tanks, i.e., two ends of the separation membrane, are provided. The enrichment side of the first-stage separation membrane 121 is connected to the next-stage membrane separation system 1, and the retentate gas on the retentate side of the first-stage separation membrane 121 is further enriched by passing through the second-stage separation membrane 122. The helium gas on the enrichment side of the second-stage separation membrane 122 is recycled to the first-stage separation membrane 121, while the retentate gas of the second-stage separation membrane 122 is not recycled but discharged, ensuring that on the basis of fully recycling the retentate gas, the impurity gas content of the raw material gas will not become higher and higher, and further ensuring the purity of helium gas.

[0042] Example 2

[0043] The difference between this example and Example 1 is only that in this example, the membrane separation system 1 includes a first-stage membrane separation module 11, a second-stage membrane separation module 12, a third-stage membrane separation module 13, and a fourth-stage membrane separation module 14 that are connected in sequence.

[0044] In this example, the reflux pipeline includes a first reflux pipe fitting 61 for recycling the retentate gas of the second-stage membrane separation module 12 to the second-stage membrane separation module 12, a second reflux pipe fitting 62 for recycling the retentate gas of the third-stage membrane separation module 13 to the second-stage membrane separation module 12, and a third reflux pipe fitting 63 for recycling the retentate gas of the fourth-stage membrane separation module 14 to the third-stage membrane separation module 13.

[0045] In this example, the second-stage membrane separation module 12 includes a first-stage separation membrane 121 connected to the enrichment side of the first-stage membrane separation module 11 and a second-stage separation membrane 122 connected to the retentate side of the first-stage membrane separation module 11. The enrichment side of the second-stage separation membrane 122 is connected to the permeation side of the first-stage separation membrane 121 through the first reflux pipe fitting 61.

[0046] In this example, the membrane separation system 1 further includes a compressor system for compressing gas to provide permeation power. The compressor system includes a first compressor 51 for introducing natural gas into the second-stage membrane separation module 12, a second compressor 52 for introducing natural gas into the third-stage membrane separation module 13, a third compressor 53 for introducing natural gas into the fourth-stage membrane separation module 14, and a fourth compressor 54 for introducing natural gas into the subsequent treatment system.

[0047] In this example, the purification device 2 adopts a pressure swing adsorption device.

[0048] Example 3

[0049] The difference between this embodiment and Embodiment 1 lies only in that, in this embodiment, the membrane separation system 1 includes a primary membrane separation module 11, a secondary membrane separation module 12, a tertiary membrane separation module 13, a quaternary membrane separation module 14, and a quinary membrane separation module 15 that are connected in sequence.

[0050] In this embodiment, the reflux pipeline includes a reflux pipe for recovering the retentate gas of the primary membrane separation module 11, the secondary membrane separation module 12, and the tertiary membrane separation module 13 into the raw material gas.

[0051] In this embodiment, the quaternary membrane separation module 14 includes a first-stage separation membrane 141 connected to the enrichment side of the tertiary membrane separation module 13 and a second-stage separation membrane 142 connected to the retentate side of the tertiary membrane separation module 13. The enrichment side of the second-stage separation membrane 142 is connected to the permeate side of the first-stage separation membrane 141 through the first reflux pipe fitting 61.

[0052] In this embodiment, the purification device 2 uses molecular sieves to remove oxygen.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An integrated natural gas wellhead helium extraction system, comprising a membrane separation system (1) for extracting crude helium, characterized in that: It also includes a cryogenic adsorption system (3) for nitrogen and neon removal; the membrane separation system (1) includes a multi-stage membrane separation component connected in sequence, and a reflux pipeline for circulating and refluxing is provided between the membrane separation components.

2. The integrated natural gas wellhead helium extraction system according to claim 1, wherein: The membrane separation component includes a separation tank, an enrichment membrane for helium permeation measurement is provided at both ends of the separation tank, and a retentate membrane for discharging the retentate gas, and the enrichment side in the middle section of the separation tank is connected to the permeation side of the lower-level separation tank in sequence.

3. The integrated natural gas wellhead helium extraction system according to claim 2, wherein: The membrane separation system (1) includes a primary membrane separation component (11), a secondary membrane separation component (12), a tertiary membrane separation component (13), and a quaternary membrane separation component (14) connected in sequence.

4. The integrated natural gas wellhead helium extraction system according to claim 3, wherein: The reflux pipeline includes a first reflux pipe fitting (61) for recovering the retentate gas of the secondary membrane separation component (12) to the secondary membrane separation component (12), a second reflux pipe fitting (62) for recovering the retentate gas of the tertiary membrane separation component (13) to the secondary membrane separation component (12), and a third reflux pipe fitting (63) for recovering the retentate gas of the quaternary membrane separation component (14) to the tertiary membrane separation component (13).

5. The integrated natural gas wellhead helium extraction system according to claim 4, characterized in that: The secondary membrane separation component (12) includes a first-stage separation membrane (121) connected to the enrichment side of the primary membrane separation component (11) and a second-stage separation membrane (122) connected to the retentate side of the primary membrane separation component (11), and the enrichment side of the second-stage separation membrane (122) is connected to the permeation side of the first-stage separation membrane (121) through the first reflux pipe fitting (61).

6. An integrated natural gas wellhead helium extraction system according to any one of claims 1-5, characterized in that: The membrane separation system (1) also includes a compressor system for compressing gas to provide permeation power, and the compressor system includes a first compressor (51) for introducing natural gas into the secondary membrane separation component (12), a second compressor (52) for introducing natural gas into the tertiary membrane separation component (13), a third compressor (53) for introducing natural gas into the quaternary membrane separation component (14), and a fourth compressor (54) for introducing natural gas into the subsequent treatment system.

7. An integrated natural gas wellhead helium extraction system according to any one of claims 1-5, characterized in that: It also includes a pretreatment system (7) for pre-treating natural gas before membrane entry and a purification device (2) for purifying natural gas after membrane permeation treatment.

8. An integrated natural gas wellhead helium extraction system according to any one of claims 1-5, characterized in that: The cryogenic adsorption system (3) includes a helium purifier for nitrogen removal and a neon removal cold box for neon removal.

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