Neon removal system for producing high-purity helium

Abstract

The invention provides a neon removal system for producing high-purity helium, and particularly relates to the technical field of gas purification, and the neon removal system for producing the high-purity helium comprises a circulation unit and a purification unit, wherein the circulating unit comprises a compressor, an oil filtering device, a first heat exchanger, a second heat exchanger, a first adsorber group, a third heat exchanger, an expansion machine and a fourth heat exchanger; the circulating unit further comprises a liquid nitrogen source, a pipeline of the liquid nitrogen source is connected with one inlet of the second heat exchanger, and the liquid nitrogen source is connected to the outside from an outlet of the second heat exchanger; the purification unit comprises a first heat exchanger, a second heat exchanger, a third heat exchanger and a second adsorber group, through pre-cooling of the liquid nitrogen source and expansion of the expansion machine, the raw material helium is cooled to 20 K, then freezing condensation separation is conducted through the second adsorber group in the 20 K temperature zone, and high-purity helium which is lower in neon content and meets the requirement can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of gas purification, and particularly to a neon removal system for producing high-purity helium gas. Background Art

[0002] Helium is a scarce and important strategic resource. With the progress of technology and the development of society, it is widely used in industries such as national defense, aerospace, cryogenic superconductivity, nuclear magnetic resonance, large science projects, semiconductor chips, and optical fibers, and the annual demand for helium shows an increasing trend.

[0003] Currently, helium mainly comes from natural gas and is extracted through membrane separation, pressure swing adsorption, and cryogenic methods in helium-rich natural gas. During the extraction process, due to the large differences in physical properties between various natural gas hydrocarbons, nitrogen, argon, etc. and helium, it is easy to remove these gases. However, since the melting point and boiling point of neon do not exceed 30K, for trace levels of neon content, it is very difficult to process the neon content to meet the national standard requirements for high-purity helium through condensation adsorption in the liquid nitrogen temperature range. Summary of the Invention

[0004] In order to solve the problem that the existing helium production device cannot remove trace levels of neon, the present invention proposes a neon removal system for producing high-purity helium gas.

[0005] The present invention is achieved through the following technical solutions:

[0006] The neon removal system for producing high-purity helium gas proposed by the present invention includes a circulation unit and a purification unit, wherein:

[0007] The circulation unit includes a compressor, an oil filtering device, a first heat exchanger, a second heat exchanger, a first adsorber group, a third heat exchanger, an expander, and a fourth heat exchanger. The outlet end of the compressor is sequentially connected to the oil filtering device, the first heat exchanger, the second heat exchanger, the first adsorber group, the third heat exchanger, the expander, and the fourth heat exchanger, and is sequentially connected from the outlet end of the fourth heat exchanger to the other side of the third heat exchanger, the first heat exchanger, and the inlet end of the compressor to form a loop;

[0008] The circulation unit further includes a liquid nitrogen source, and the pipeline of the liquid nitrogen source is connected to an inlet of the second heat exchanger and leads out from the outlet of the second heat exchanger to the outside;

[0009] The purification unit includes a first heat exchanger, a second heat exchanger, a third heat exchanger, and a second adsorber group. The gas inlet is sequentially connected to the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, and the second adsorber group, and is sequentially connected back from the outlet end of the second adsorber group to the other end of the third heat exchanger and the other end of the first heat exchanger.

[0010] Further, the second adsorber group includes two second adsorbers, and two branches at the outlet end of the fourth heat exchanger are respectively connected to the two second adsorbers and converge to the inlet end of the three heat exchangers.

[0011] Further, the second adsorber group further includes a first regulating valve, and the two first regulating valves are respectively arranged on the branches from the two second adsorbers to the outlet of the fourth heat exchanger.

[0012] Further, it further includes an inflation unit, and the inflation unit includes a buffer tank. One branch at the outlet end of the buffer tank is connected to the outlet end of the oil filtering device, and the other branch is connected to the inlet end of the compressor.

[0013] Further, it further includes a second regulating valve. The outlet end of the buffer tank is connected to the second regulating valve and is respectively connected to the outlet end of the oil filtering device and the inlet end of the compressor through two branches.

[0014] Further, the inflation unit further includes a third regulating valve. One third regulating valve is arranged on the branch from the oil filtering device to the outlet of the second regulating valve, and the other third regulating valve is arranged on the branch from the compressor to the second regulating valve.

[0015] Further, it further includes a fourth regulating valve, and both ends of the fourth regulating valve are respectively connected to the outlet end of the oil filtering device and the inlet end of the compressor.

[0016] Further, it further includes a fifth regulating valve. One fifth regulating valve is arranged between the oil filtering device and the inlet of the first heat exchanger, and the other fifth regulating valve is arranged between the outlet of the first heat exchanger and the inlet of the compressor.

[0017] Further, a sixth regulating valve is provided on the pipeline from the outlet end of the third heat exchanger to the inlet end of the expander.

[0018] Further, it further includes a seventh regulating valve, and the seventh regulating valve is arranged between the inlet of the liquid nitrogen source and one inlet of the first heat exchanger.

[0019] Advantages of the present invention:

[0020] The neon removal system for producing high-purity helium proposed by the present invention uses liquid nitrogen for precooling and an expander for expansion, and in combination with a circulation system, can cool the raw material helium gas to the 20K temperature range. Subsequently, in the 20K temperature range, the purification of trace neon content in high-purity helium gas is achieved by means of refrigeration condensation and cryo-adsorption, with higher applicability and can meet the standard requirements. Description of the Drawings

[0021] Figure 1Structural diagram of the neon removal system for producing high-purity helium of the present invention;

[0022] In the figure: compressor 1, oil filter device 2, first heat exchanger 3, second heat exchanger 4, third heat exchanger 5, fourth heat exchanger 6, first adsorber 7, expander 8, buffer tank 9, second adsorber 10, liquid nitrogen source 11, first regulating valve 12, second regulating valve 13, third regulating valve 14, fourth regulating valve 15, fifth regulating valve 16, sixth regulating valve 17, seventh regulating valve 18;

[0023] The realization, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0024] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0025] Please refer to Figure 1 , the present invention provides a neon removal system for producing high-purity helium, which includes a circulation unit and a purification unit, wherein:

[0026] The circulation unit includes a compressor 1, an oil filter device 2, a first heat exchanger 3, a second heat exchanger 4, a first adsorber 7 group, a third heat exchanger 5, an expander 8 and a fourth heat exchanger 6. The outlet end of the compressor 1 is sequentially connected to the oil filter device 2, the first heat exchanger 3, the second heat exchanger 4, the first adsorber 7 group, the third heat exchanger 5, the expander 8 and the fourth heat exchanger 6, and is sequentially connected from the outlet end of the fourth heat exchanger 6 to the other side of the third heat exchanger 5, the first heat exchanger 3 and the inlet end of the compressor 1 to form a loop;

[0027] The circulation unit further includes a liquid nitrogen source 11. The pipeline of the liquid nitrogen source 11 is connected to an inlet of the second heat exchanger 4 and leads out from the outlet of the second heat exchanger 4 to the outside;

[0028] The purification unit includes a first heat exchanger 3, a second heat exchanger 4, a third heat exchanger 5 and a second adsorber 10 group. The gas inlet is sequentially connected to the first heat exchanger 3, the second heat exchanger 4, the third heat exchanger 5, the fourth heat exchanger 6 and the second adsorber 10 group, and is sequentially connected back from the outlet end of the second adsorber 10 group to the other end of the third heat exchanger 5 and the other end of the first heat exchanger 3.

[0029] In this embodiment:

[0030] The compressor 1 is a screw compressor 1 for compressing helium;

[0031] The oil filter device 2 is used to remove impurities in helium;

[0032] The first heat exchanger 3, the second heat exchanger 4, and the third heat exchanger 5 are arranged in the cold box to recover cold energy and supply part of the cold energy to the purification unit;

[0033] Seven groups of the first adsorbers 7 are used to adsorb nitrogen, and the first adsorbers 7 are 80K adsorbers

[0034] Ten groups of the second adsorbers 10 are used to adsorb neon, and the second adsorbers 10 are 20K adsorbers;

[0035] The liquid nitrogen source 11 is used to precool helium, and the liquid nitrogen source 11 provides cold energy for the second heat exchanger 4 and is converted into nitrogen and flows out from the outlet;

[0036] The expander 8 is used to expand the gas to lower the temperature;

[0037] Specifically, in the circulation unit, the high-pressure helium gas compressed by the compressor 1 and filtered by the oil filtering device 2 enters the cold box. The high-purity helium gas exchanges heat with the refluxing low-temperature helium gas in the first heat exchanger 3 for preliminary precooling and temperature reduction, and then exchanges heat with the liquid nitrogen source 11 in the second heat exchanger 4 to be cooled down to 80K. Subsequently, it enters the first adsorbers 7, and trace nitrogen, oxygen, argon and other impurity gases in the high-purity helium gas are adsorbed. Immediately afterwards, it exchanges heat with the refluxing low-temperature helium gas in the third heat exchanger 5, then enters the expander 8 for temperature reduction. Subsequently, it sequentially passes through the fourth heat exchanger 6, the third heat exchanger 5, and the first heat exchanger 3 to recover cold energy, and then enters the compressor 1 for recycling;

[0038] In the purification unit, the high-purity helium gas is first precooled in the first heat exchanger 3, then exchanges heat with the liquid nitrogen in the second heat exchanger 4, and then exchanges heat with the low-temperature helium gas in the third heat exchanger 5 from the circulation unit. The temperature of the high-purity helium gas is reduced to below the melting point of neon. Subsequently, it enters the ten groups of the second adsorbers 10 to adsorb neon in the helium gas, completing the purification of high-purity helium gas to remove neon. Then it sequentially passes through the third heat exchanger 5 and the first heat exchanger 3 to recover cold energy, and uses the combination of freeze condensation and low-temperature adsorption to purify the high-purity helium gas to remove neon;

[0039] The present invention can reduce the content of trace-level neon in high-purity helium gas. By making the neon-removing adsorption in the low-temperature hydrogen temperature region, which is lower than the melting point of neon under normal pressure, neon can be changed into solid particles or liquid, and then neon stays in the 20K adsorbers to complete adsorption. Compared with simply using low-temperature adsorption to remove neon in the liquid nitrogen temperature region, the content of neon in high-purity helium gas can be reduced.

[0040] Further, the ten groups of the second adsorbers 10 include two second adsorbers 10. The two branches at the outlet end of the fourth heat exchanger 6 are respectively connected to the two second adsorbers 10 and converge to the inlet end of the three heat exchangers;

[0041] The second adsorber group of 10 also includes a first regulating valve 12. Two first regulating valves 12 are respectively arranged on the branch paths from the two second adsorbers 10 to the outlet of the fourth heat exchanger 6.

[0042] In the embodiment:

[0043] The second adsorber 10 is a 20K adsorber;

[0044] The first regulating valve 12 can be used to regulate the two adsorbers;

[0045] Specifically, the two first regulating valves 12 can regulate the opening or closing of the branch paths for the gas to enter the adsorbers. The second adsorber group of 10 is provided with two second adsorbers 10 that can be switched. By using the two second adsorbers 10 for switching, a high-purity helium production mode of working while regenerating can be achieved.

[0046] Furthermore, it also includes an inflation unit. The inflation unit includes a buffer tank 9. One branch path at the outlet end of the buffer tank 9 is connected to the outlet end of the oil filtering device 2, and the other branch path is connected to the inlet end of the compressor 1;

[0047] It also includes a second regulating valve 13. The outlet end of the buffer tank 9 is connected to the second regulating valve 13 and is respectively connected to the outlet end of the oil filtering device 2 and the inlet end of the compressor 1 through two branch paths;

[0048] The inflation unit also includes a third regulating valve 14. One third regulating valve 14 is arranged on the branch path from the oil filtering device 2 to the outlet of the second regulating valve 13, and the other third regulating valve 14 is arranged on the branch path from the compressor 1 to the outlet of the second regulating valve 13.

[0049] In this embodiment:

[0050] The buffer tank 9 is used to introduce high-purity helium;

[0051] The second regulating valve 13 is used to open and close the buffer tank 9;

[0052] The third regulating valve 14 is used to control the helium to enter the circuit before compression or the circuit after compression;

[0053] Specifically, the high-purity helium from the buffer tank 9 passes through the second regulating valve 13 and is then respectively transported to different branch paths through the two third regulating valves 14 and is transported to the circuit to complete the removal of neon.

[0054] Furthermore, it also includes a fourth regulating valve 15. The two ends of the fourth regulating valve 15 are respectively connected to the outlet end of the oil filtering device 2 and the inlet end of the compressor 1.

[0055] In this embodiment:

[0056] The fourth regulating valve 15 is used to regulate the air pressure balance

[0057] Specifically, the fourth regulating valve 15 is connected to the outlet end of the oil filtering device 2 and the inlet end of the compressor 1. When the pressure at one end is too high or too low, opening the fourth regulating valve 15 can connect the gases at both ends, thereby regulating the air pressure balance.

[0058] Furthermore, it further includes a fifth regulating valve 16. One fifth regulating valve 16 is arranged between the oil filtering device 2 and the inlet of the first heat exchanger 3, and the other fifth regulating valve 16 is arranged between the outlet of the first heat exchanger 3 and the inlet of the compressor 1;

[0059] A sixth regulating valve 17 is provided between the outlet end of the third heat exchanger 5 and the inlet end of the expander 8.

[0060] In this embodiment:

[0061] The fifth regulating valve 16 is used for switching control of the connection of the cold box;

[0062] The sixth regulating valve 17 is used for controlling the flow rate after helium gas;

[0063] Specifically, when the fifth regulating valve 16 is closed, it can prevent helium gas from entering the heat exchanger inside the cold box, thereby closing the circulation unit. The sixth regulating valve 17 can regulate the pressure and flow rate of the helium gas after heat exchange and cooling, so as to facilitate the subsequent expansion of the expander 8.

[0064] Furthermore, it further includes a seventh regulating valve 18, and the seventh regulating valve 18 is arranged between the inlet of the liquid nitrogen source 11 and one inlet of the first heat exchanger 3.

[0065] In this embodiment:

[0066] The seventh regulating valve 18 regulates the connection of the liquid nitrogen source 11;

[0067] Specifically, the seventh regulating valve 18 is opened and closed to control the inflow of the liquid nitrogen source 11 into the first heat exchanger 3 and to control the flow rate of the liquid nitrogen flowing into the first heat exchanger 3 from the liquid nitrogen source 11.

[0068] Of course, the present invention can also have many other embodiments. Based on this embodiment, other embodiments obtained by those of ordinary skill in the art without any creative labor belong to the scope protected by the present invention.

Claims

1. A neon removal system for producing high-purity helium gas, characterized in that, It includes a circulation unit and a purification unit, where: The circulation unit includes a compressor, an oil filtering device, a first heat exchanger, a second heat exchanger, a first adsorber group, a third heat exchanger, an expander, and a fourth heat exchanger. The outlet end of the compressor is sequentially connected to the oil filtering device, the first heat exchanger, the second heat exchanger, the first adsorber group, the third heat exchanger, the expander, and the fourth heat exchanger, and is sequentially connected from the outlet end of the fourth heat exchanger to the other side of the third heat exchanger, the first heat exchanger, and the inlet end of the compressor to form a loop; The circulation unit further includes a liquid nitrogen source. The pipeline of the liquid nitrogen source is connected to an inlet of the second heat exchanger and leads out from the outlet of the second heat exchanger to the outside; The purification unit includes a first heat exchanger, a second heat exchanger, a third heat exchanger, and a second adsorber group. The gas inlet is sequentially connected to the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, and the second adsorber group, and is sequentially connected back from the outlet end of the second adsorber group to the other end of the third heat exchanger and the other end of the first heat exchanger.

2. The neon removal system for producing high-purity helium according to claim 1, characterized in that, The second adsorber group includes two second adsorbers. Two branches at the outlet end of the fourth heat exchanger are respectively connected to the two second adsorbers and converge to the inlet end of the third heat exchanger.

3. The neon removal system for producing high-purity helium according to claim 2, characterized in that, The second adsorber group further includes a first regulating valve. The two first regulating valves are respectively arranged on the branches from the two second adsorbers to the outlet of the fourth heat exchanger.

4. The neon removal system for producing high-purity helium according to claim 1, characterized in that, It further includes an inflation unit. The inflation unit includes a buffer tank. One branch at the outlet end of the buffer tank is connected to the outlet end of the oil filtering device, and the other branch is connected to the inlet end of the compressor.

5. The neon removal system for producing high-purity helium according to claim 4, characterized in that, It further includes a second regulating valve. The outlet end of the buffer tank is connected to the second regulating valve and is respectively connected to the outlet end of the oil filtering device and the inlet end of the compressor through two branches.

6. The neon removal system for producing high-purity helium according to claim 5, characterized in that, The inflation unit further includes a third regulating valve. One third regulating valve is arranged on the branch from the oil filtering device to the outlet of the second regulating valve, and the other third regulating valve is arranged on the branch from the compressor to the outlet of the second regulating valve.

7. The neon removal system for producing high-purity helium according to claim 6, characterized in that, It further includes a fourth regulating valve. The two ends of the fourth regulating valve are respectively connected to the outlet end of the oil filtering device and the inlet end of the compressor.

8. The neon removal system for producing high-purity helium according to claim 7, characterized in that, It further includes a fifth regulating valve. One fifth regulating valve is arranged between the oil filtering device and the inlet of the first heat exchanger, and the other fifth regulating valve is arranged between the outlet of the first heat exchanger and the inlet of the compressor.

9. The neon removal system for producing high-purity helium according to claim 1, characterized in that, A sixth regulating valve is provided on the pipeline from the outlet end of the third heat exchanger to the inlet end of the expander.

10. The neon removal system for producing high-purity helium according to claim 1, characterized in that, It further includes a seventh regulating valve. The seventh regulating valve is arranged between the inlet of the liquid nitrogen source and an inlet of the first heat exchanger.

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