System and method for purifying helium from multi-component gas mixture containing helium

Abstract

The present application relates to the technical field of gas purification. Disclosed are a system and method for purifying helium from a multi-component gas mixture containing helium. The system comprises a cryogenic cooling unit, a cryogenic adsorption unit and a helium-product storage tank, which are sequentially in communication with each other, wherein the cryogenic cooling unit comprises a feeding system, a cryogenic Dewar flask I and a gas-liquid separator, the gas-liquid separator being located inside the cryogenic Dewar flask I; the cryogenic adsorption unit comprises a cryogenic Dewar flask II and an adsorption column, the adsorption column being located inside the cryogenic Dewar flask II; and the multi-component gas mixture containing helium enters the gas-liquid separator by means of the feeding system to undergo separation, separated crude helium enters the adsorption column through a pipeline, and a helium product which has been subjected to adsorption separation by means of the adsorption column enters the helium-product storage tank. The purification method using the system is simple and efficient, and needs no catalytic dehydrogenation process. By means of one cryogenic condensation separation and one cryogenic adsorption separation, high-purity helium or ultrapure helium with a purity greater than 99.999% can be obtained by separation.

Description

A system and method for purifying helium from a multi-component mixed gas containing helium TECHNICAL FIELD

[0001] The present application relates to a system and method for purifying helium from a multi-component mixed gas containing helium, and belongs to the field of gas purification. BACKGROUND

[0002] Helium is a very precious rare gas, which has very important uses in the fields of national defense, semiconductors, aerospace and medical treatment. China is short of helium resources, and about 95% of helium is dependent on imports, so helium has been listed as a strategic resource in China.

[0003] Most of China's helium resources are obtained from natural gas, and in addition to helium, other gases are multi-component mixed gases such as nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon, etc. The existing low-temperature helium extraction technology mainly includes deep cooling separation and purification technology, including catalytic dehydrogenation, low-temperature demethanization, catalytic deoxidation, low-temperature denitrification, adsorption and neon removal, etc. to realize the production of high-purity helium (more than 99.999%). This process has many devices, a long technical route, high cost, and lacks market competitiveness. In this process, hydrogen is removed by catalytic oxidation, which has high energy consumption, complex device, and many uncontrollable factors, and the adsorbent used in the adsorption and neon removal process is generally activated carbon, which has weak adsorption capacity for neon and small adsorption amount. Therefore, it is urgent to develop a simpler and more efficient adsorption process and adsorbent for purifying helium from a multi-component mixed gas containing helium. SUMMARY

[0004] The purpose of the present application is to provide a simpler and more efficient system and method for purifying helium from a multi-component mixed gas containing helium in view of the deficiencies in the current technology. By subjecting the multi-component mixed gas containing helium to one low-temperature condensation separation and one low-temperature adsorption separation, high-purity helium or ultrapure helium with a purity of more than 99.999% can be obtained from the multi-component mixed gas containing helium.

[0005] According to a first aspect of the present application, a system for purifying helium from a multi-component mixed gas containing helium is provided.

[0006] A system for purifying helium from a multi-component mixed gas containing helium, the system comprising a low-temperature cooling unit, a low-temperature adsorption unit and a helium product tank connected in sequence;

[0007] The low-temperature cooling unit comprises a feed system, a low-temperature dewar I and a gas-liquid separator;

[0008] The gas-liquid separator is in the low-temperature dewar I;

[0009] The low-temperature adsorption unit comprises a low-temperature Dewar flask II and an adsorption column;

[0010] The adsorption column is in the low-temperature Dewar flask II;

[0011] The multi-component mixed gas containing helium is separated in the gas-liquid separator, and the separated crude helium is introduced into the adsorption column through a pipeline, and the helium product separated by the adsorption column is introduced into the helium product storage tank.

[0012] Optionally, the low-temperature adsorption unit comprises two parallel low-temperature adsorption units, denoted as low-temperature adsorption unit a and low-temperature adsorption unit b;

[0013] The low-temperature adsorption unit a comprises a low-temperature Dewar flask IIa and an adsorption column a;

[0014] The low-temperature adsorption unit b comprises a low-temperature Dewar flask IIb and an adsorption column b.

[0015] According to a second aspect of the present application, a method for purifying helium from a multi-component mixed gas containing helium is provided.

[0016] A method for purifying helium from a multi-component mixed gas containing helium, using the system described above;

[0017] The method comprises the following steps:

[0018] S1, using high-purity helium to purge and pressurize the entire system, and introducing liquid nitrogen into the low-temperature Dewar flask I and the low-temperature Dewar flask II;

[0019] S2, introducing the multi-component mixed gas containing helium into the low-temperature Dewar flask I through the feed system of the low-temperature cooling unit, condensing and liquefying, and then performing gas-liquid separation in the gas-liquid separator to obtain a liquid phase and a gas phase, wherein the gas phase is crude helium;

[0020] S3, introducing the crude helium into the adsorption column of the low-temperature adsorption unit for adsorption and separation, and introducing the helium product separated into the helium product storage tank.

[0021] Optionally, the purging and pressurizing use 99.999% high-purity helium.

[0022] Optionally, in step S3, two parallel low-temperature adsorption units are used;

[0023] After the adsorption column a of the low-temperature adsorption unit a is saturated, the crude helium is switched into the adsorption column b of the low-temperature adsorption unit b for adsorption and separation;

[0024] At the same time of switching, the adsorption column a is regenerated, after the adsorption column a is regenerated, liquid nitrogen is introduced into the low-temperature dewar flask IIa of the low-temperature adsorption unit a to perform temperature balancing, after the adsorption column b is saturated, the crude helium gas is switched into the regenerated adsorption column a to perform adsorption separation, at the same time of switching, the adsorption column b is regenerated.

[0025] Optionally, the operation is repeated.

[0026] By repeating the operation, high-purity helium or ultra-pure helium with a purity greater than 99.999% can be continuously obtained.

[0027] Optionally, in step S2, the helium-containing multi-component mixed gas includes He and impurity gas.

[0028] The impurity gas includes at least one of N2, Ar, H2, CO, CO2, Ne, O2, CH4.

[0029] The purity of the separated helium product is greater than 99.999%.

[0030] The gas-liquid separation obtains a liquid phase and a gas phase, the liquid phase is liquid nitrogen and liquid methane, and the gas phase is crude helium gas containing nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon and other impurity gases.

[0031] Optionally, in step S2, the condensation liquefaction pressure is 0.5-10 MPa.

[0032] Optionally, the condensation liquefaction pressure is selected from any value or a range value between any two values of 0.5 MPa, 1.0 MPa, 2.0 MPa, 3.0 MPa, 4.0 MPa, 5.0 MPa, 6.0 MPa, 7.0 MPa, 8.0 MPa, 9.0 MPa, and 10.0 MPa.

[0033] Optionally, in step S3, the adsorption separation pressure is 0.1-5 MPa.

[0034] Optionally, the adsorption separation pressure is selected from any value or a range value between any two values of 0.1 MPa, 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa, 3.5 MPa, 4.0 MPa, 4.5 MPa, and 5.0 MPa.

[0035] Optionally, the adsorption column is provided with an adsorbent, and the adsorbent is a barium ion-exchanged molecular sieve.

[0036] Optionally, the exchange degree of barium ions in the adsorbent is 50%-100%.

[0037] Optionally, the molecular sieve is selected from at least one of LTA, FAU, MFI, BEA, MOR, CHA, EAB, AEL, and TON topologies.

[0038] Optionally, the molecular sieve is selected from at least one of A, X, ZSM-5, Beta, MOR, SAPO-34, EAB, AlPO4-11, and ZSM-22.

[0039] Optionally, the regeneration process comprises:

[0040] First, the liquid nitrogen in the low-temperature dewar bottle where the adsorption column a or b is located is discharged, then high-purity nitrogen gas after heating is used to purge the adsorption column a or b and the associated pipelines of the low-temperature adsorption unit, and finally vacuum is applied.

[0041] Optionally, the low temperature in the operation process is provided by liquid nitrogen under normal pressure or pressure.

[0042] As a specific embodiment, the method for purifying helium from a multi-component mixed gas containing helium comprises the following steps:

[0043] (1) high-purity helium of 99.999% is used to purge and pressurize the entire system, and the liquid nitrogen in the liquid nitrogen tank is introduced into the low-temperature condensing liquid nitrogen dewar and the low-temperature adsorption liquid nitrogen dewar through a pump;

[0044] (2) the multi-component mixed gas containing helium enters the low-temperature condensing unit, and the high-boiling-point gas in the mixed gas is condensed and liquefied at a liquid nitrogen temperature and a certain pressure, most of the nitrogen and methane in the mixed gas are condensed, and then gas-liquid separation is performed, the liquid phase is liquid nitrogen and liquid methane, and the gas phase is crude helium;

[0045] (3) the gas phase crude helium not condensed in step (2) enters the adsorption column a of the low-temperature adsorption unit, and the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon, etc. in the gas phase crude helium are adsorbed by the adsorbent in the adsorption column a at a liquid nitrogen temperature and a certain adsorption pressure, and then high-purity helium or ultrapure helium with a purity greater than 99.999% is obtained and introduced into a helium product storage tank;

[0046] (4) after the adsorption column a of the low-temperature adsorption unit is saturated, the gas phase crude helium not condensed in step (2) is switched into the adsorption column b of the low-temperature adsorption unit, and high-purity helium or ultrapure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a certain adsorption pressure; at the same time, the adsorption column a is regenerated;

[0047] (5) After the regeneration of adsorption column a is completed, 99.999% high-purity helium is used to purge and pressurize the adsorption column a, and liquid nitrogen is introduced into the low-temperature dewar in which the adsorption column a is located to perform temperature balancing. After the adsorption column b of the low-temperature adsorption unit is saturated, the gaseous crude helium gas that is not condensed in step (3) is switched into the adsorption column a of the low-temperature adsorption unit to continue to obtain high-purity helium or ultrapure helium with a purity greater than 99.999% at a liquid nitrogen temperature and a certain adsorption pressure. At the same time, the adsorption column b is regenerated.

[0048] (6) After the regeneration of adsorption column b is completed, 99.999% high-purity helium is used to purge and pressurize the adsorption column b, and liquid nitrogen is introduced into the low-temperature dewar in which the adsorption column b is located to perform temperature balancing. After the adsorption column a is saturated, the gaseous crude helium gas that is not condensed in step (3) is switched into the adsorption column b of the low-temperature adsorption unit to continue to obtain high-purity helium or ultrapure helium with a purity greater than 99.999% at a liquid nitrogen temperature and a certain adsorption pressure. At the same time, the adsorption column a is regenerated.

[0049] (7) The steps (4) to (6) are repeated to continuously obtain high-purity helium or ultrapure helium with a purity greater than 99.999%.

[0050] The beneficial effects that can be produced by the present application include:

[0051] The system and method for purifying helium from a multi-component mixed gas containing helium provided by the present application is simple and efficient in the process of purifying helium from a multi-component mixed gas containing helium, and does not need a catalytic dehydrogenation process. The adsorbent in the present application has strong adsorption capacity for various impurity gases in helium, such as nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon, etc. High-purity helium or ultrapure helium with a purity greater than 99.999% can be continuously obtained. BRIEF DESCRIPTION OF DRAWINGS

[0052] FIG. 1 is a process flow diagram for purifying helium from a multi-component mixed gas containing helium.

[0053] List of components and reference numerals: 1, low-temperature condensation unit 2, low-temperature adsorption unit a 3, low-temperature adsorption unit b 4, feed system 5, low-temperature condensation liquid nitrogen dewar 6, gas-liquid separator 7, low-temperature adsorption liquid nitrogen dewar a 8, adsorption column a 9, low-temperature adsorption liquid nitrogen dewar b 10, adsorption column b 11, helium product storage tank DETAILED DESCRIPTION

[0054] The present application will be described in detail below in conjunction with examples, but the present application is not limited to these examples.

[0055] Unless otherwise specified, the raw materials in the examples of the present application are purchased through commercial channels.

[0056] As shown in FIG. 1, the process flow diagram for purifying helium from a multi-component mixed gas containing helium used in the examples is shown.

[0057] (1) The whole system is purged and pressurized with 99.999% high-purity helium, and the liquid nitrogen in the liquid nitrogen tank is pumped into the low-temperature condensing liquid nitrogen Dewar flask 5 and the low-temperature adsorbing liquid nitrogen Dewar flask a 7 and the low-temperature adsorbing liquid nitrogen Dewar flask b 9;

[0058] (2) The multi-component mixed gas containing helium enters the low-temperature condensing unit 1 through the feeding system 4, and the high-boiling-point gas in the mixed gas is condensed and liquefied at a liquid nitrogen temperature and a certain pressure, most of the nitrogen and methane in the mixed gas are condensed, and then the gas-liquid separation is performed through the gas-liquid separator 6, the liquid phase is liquid nitrogen and liquid methane, and the gas phase is crude helium gas;

[0059] (3) The crude helium gas in the gas phase which is not condensed in step (2) enters the adsorption column a 8 of the low-temperature adsorbing unit a 2, and the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon and other gases in the crude helium gas are adsorbed by the adsorbent in the adsorption column a 8 at a liquid nitrogen temperature and a certain adsorption pressure, and then high-purity helium or ultra-pure helium with a purity greater than 99.999% is obtained and introduced into the helium product storage tank 11;

[0060] (4) After the adsorption column a 8 of the low-temperature adsorbing unit a 2 is saturated, the crude helium gas in the gas phase which is not condensed in step (2) is switched to enter the adsorption column b 10 of the low-temperature adsorbing unit b 3, and high-purity helium or ultra-pure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a certain adsorption pressure; at the same time, the adsorption column a 8 is regenerated;

[0061] (5) After the regeneration of the adsorption column a 8 is completed, the adsorption column a 8 is purged and pressurized with 99.999% high-purity helium again, and liquid nitrogen is introduced into the low-temperature Dewar flask in which the adsorption column a 8 is located to perform temperature balancing, and the adsorption column b 10 of the low-temperature adsorbing unit is saturated, the crude helium gas in the gas phase which is not condensed in step (3) is switched to enter the adsorption column a 8 of the low-temperature adsorbing unit, and high-purity helium or ultra-pure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a certain adsorption pressure; at the same time, the adsorption column b 10 is regenerated.

[0062] (6) After the regeneration of the adsorption column b 10 is completed, the adsorption column b 10 is purged and pressurized with 99.999% high-purity helium again, and liquid nitrogen is introduced into the low-temperature Dewar flask in which the adsorption column b 10 is located to perform temperature balancing, and the adsorption column a 8 is saturated;

[0063] (7) The steps (4) to (6) are repeated to continuously obtain high-purity helium or ultra-pure helium with a purity greater than 99.999%.

[0064] Example 1

[0065] The whole system is purged and pressurized with 99.999% high-purity helium, and the liquid nitrogen in the liquid nitrogen tank is pumped into the low-temperature condensing liquid nitrogen dewar and the low-temperature adsorbing liquid nitrogen dewar. The multi-component mixed gas containing helium (He, N2, Ar, H2, CO, CO2, Ne, O2, CH4) is introduced into the low-temperature condensing unit, and the high-boiling-point gas in the mixed gas is condensed and liquefied at a liquid nitrogen temperature and a pressure of 5 MPa. Subsequently, gas-liquid separation is performed, and the uncondensed gas-phase crude helium gas enters the adsorption column a of the low-temperature adsorbing unit, and the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon and other gases therein are adsorbed by the Ba-X adsorbent (the exchange degree of barium ions is 50%) in the adsorption column at a liquid nitrogen temperature and a pressure of 2 MPa. Thus, high-purity helium or ultrapure helium with a purity greater than 99.999% is obtained and introduced into a helium product storage tank.

[0066] After the adsorption column a of the low-temperature adsorbing unit is saturated, the gas-phase crude helium gas that has not been condensed after passing through the low-temperature condensing system is switched into the adsorption column b of the low-temperature adsorbing unit, and high-purity helium or ultrapure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a pressure of 2 MPa. At the same time, the adsorption column a is regenerated. The regeneration process is as follows: the liquid nitrogen in the dewar bottle where the low-temperature adsorption column a is located is pumped out to the liquid nitrogen tank, then high-purity nitrogen gas after heating is used to purge the adsorption column a of the adsorbing unit and the auxiliary pipelines, and finally vacuumization is performed. After the regeneration of the adsorption column a is completed, 99.999% high-purity helium is used to purge and pressurize the adsorption column a, and liquid nitrogen is introduced into the low-temperature dewar where the adsorption column a is located for temperature balancing. After the adsorption column b is saturated, the adsorption column a is switched back.

[0067] Example 2

[0068] The whole system is purged and pressurized with 99.999% high-purity helium, and the liquid nitrogen in the liquid nitrogen tank is pumped into the low-temperature condensing liquid nitrogen dewar and the low-temperature adsorbing liquid nitrogen dewar. The multi-component mixed gas containing helium (He, N2, Ar, H2, CO, CO2, Ne, O2, CH4) is introduced into the low-temperature condensing unit, and the high-boiling-point gas in the mixed gas is condensed and liquefied at a liquid nitrogen temperature and a pressure of 0.5 MPa. Subsequently, gas-liquid separation is performed, and the uncondensed gas-phase crude helium gas enters the adsorption column a of the low-temperature adsorbing unit, and the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon and other gases therein are adsorbed by the Ba-A adsorbent (the exchange degree of barium ions is 75%) in the adsorption column at a liquid nitrogen temperature and a pressure of 0.1 MPa. Thus, high-purity helium or ultrapure helium with a purity greater than 99.999% is obtained and introduced into a helium product storage tank.

[0069] After the adsorption column a of the low-temperature adsorption unit is saturated, the gaseous crude helium gas that is not condensed after passing through the low-temperature condensation system is switched into the adsorption column b of the low-temperature adsorption unit, and high-purity helium or ultrapure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a pressure of 0.1 MPa; at the same time, the adsorption column a is regenerated, and the regeneration process is as follows: first, the liquid nitrogen in the dewar flask in which the low-temperature adsorption column a is located is pumped out to a liquid nitrogen tank, then high-purity nitrogen gas that is heated is used to purge the adsorption column a of the adsorption unit and the auxiliary pipelines, and finally, vacuumization is performed. After the regeneration of the adsorption column a is completed, 99.999% high-purity helium gas is used to purge and pressurize the adsorption column a, and liquid nitrogen is introduced into the low-temperature dewar flask in which the adsorption column a is located to perform temperature balancing, and after the adsorption column b is saturated, the adsorption column a is switched back.

[0070] Example 3

[0071] The entire system is purged and pressurized using 99.999% high-purity helium gas, the liquid nitrogen in the liquid nitrogen tank is pumped into the low-temperature condensation liquid nitrogen dewar flask and the low-temperature adsorption liquid nitrogen dewar flask, and the multi-component mixed gas containing helium (He, N2, Ar, H2, CO, CO2, Ne, O2, CH4) is introduced into the low-temperature condensation unit, so that the high-boiling-point gases in the mixed gas are condensed and liquefied at a liquid nitrogen temperature and a pressure of 10 MPa, and then gas-liquid separation is performed. The gaseous crude helium gas that is not condensed is introduced into the adsorption column a of the low-temperature adsorption unit, so that the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon, and the like in the gaseous crude helium gas are adsorbed by the Ba-Beta adsorbent (the exchange degree of barium ions is 100%) in the adsorption column a at a liquid nitrogen temperature and a pressure of 5 MPa, and high-purity helium or ultrapure helium with a purity greater than 99.999% is obtained and introduced into a helium product storage tank.

[0072] After the adsorption column a of the low-temperature adsorption unit is saturated, the gaseous crude helium gas that is not condensed after passing through the low-temperature condensation system is switched into the adsorption column b of the low-temperature adsorption unit, and high-purity helium or ultrapure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a pressure of 5 MPa; at the same time, the adsorption column a is regenerated, and the regeneration process is as follows: first, the liquid nitrogen in the dewar flask in which the low-temperature adsorption column a is located is pumped out to a liquid nitrogen tank, then high-purity nitrogen gas that is heated is used to purge the adsorption column a of the adsorption unit and the auxiliary pipelines, and finally, vacuumization is performed. After the regeneration of the adsorption column a is completed, 99.999% high-purity helium gas is used to purge and pressurize the adsorption column a, and liquid nitrogen is introduced into the low-temperature dewar flask in which the adsorption column a is located to perform temperature balancing, and after the adsorption column b is saturated, the adsorption column a is switched back.

[0073] Example 4

[0074] The whole system is purged and pressurized with 99.999% high-purity helium, and the liquid nitrogen in the liquid nitrogen tank is pumped into the low-temperature condensation liquid nitrogen dewar and the low-temperature adsorption liquid nitrogen dewar. The multi-component gas containing helium (He, N2, Ar, H2, CO, CO2, Ne, O2, CH4) is introduced into the low-temperature condensation unit, and the high-boiling-point gas in the mixed gas is condensed and liquefied at a liquid nitrogen temperature and a pressure of 7 MPa. Subsequently, gas-liquid separation is performed, and the uncondensed gas-phase crude helium gas enters the adsorption column a of the low-temperature adsorption unit, and the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon, etc. in the gas are adsorbed by the Ba-MOR adsorbent (the exchange degree of barium ions is 88%) in the adsorption column at a liquid nitrogen temperature and a pressure of 3 MPa, and then high-purity helium or ultrapure helium with a purity greater than 99.999% is obtained and introduced into the helium product storage tank.

[0075] After the adsorption column a of the low-temperature adsorption unit is saturated, the gas-phase crude helium gas that has not been condensed after passing through the low-temperature condensation system is switched into the adsorption column b of the low-temperature adsorption unit, and high-purity helium or ultrapure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a pressure of 3 MPa. At the same time, the adsorption column a is regenerated. The regeneration process is as follows: first, the liquid nitrogen in the dewar bottle where the low-temperature adsorption column a is located is pumped out to the liquid nitrogen tank, then high-purity nitrogen gas after heating is used to purge the adsorption column a of the adsorption unit and the auxiliary pipeline, and finally vacuumization is performed. After the regeneration of the adsorption column a is completed, 99.999% high-purity helium is used to purge and pressurize the adsorption column a, and liquid nitrogen is introduced into the low-temperature dewar where the adsorption column a is located for temperature balancing. After the adsorption column b is saturated, the adsorption column a is switched back.

[0076] Example 5

[0077] The whole system is purged and pressurized with 99.999% high-purity helium, and the liquid nitrogen in the liquid nitrogen tank is pumped into the low-temperature condensation liquid nitrogen dewar and the low-temperature adsorption liquid nitrogen dewar. The multi-component gas containing helium (He, N2, Ar, H2, CO, CO2, Ne, O2, CH4) is introduced into the low-temperature condensation unit, and the high-boiling-point gas in the mixed gas is condensed and liquefied at a liquid nitrogen temperature and a pressure of 7 MPa. Subsequently, gas-liquid separation is performed, and the uncondensed gas-phase crude helium gas enters the adsorption column a of the low-temperature adsorption unit, and the nitrogen, methane, carbon monoxide, carbon dioxide, oxygen, argon, hydrogen, neon, etc. in the gas are adsorbed by the Ba-MOR adsorbent (the exchange degree of barium ions is 88%) in the adsorption column at a liquid nitrogen temperature and a pressure of 3 MPa, and then high-purity helium or ultrapure helium with a purity greater than 99.999% is obtained and introduced into the helium product storage tank.

[0078] After the adsorption column a of the low-temperature adsorption unit is saturated, the gaseous crude helium gas that is not condensed after passing through the low-temperature condensation system is switched into the adsorption column b of the low-temperature adsorption unit, and high-purity helium or ultrapure helium with a purity greater than 99.999% is continuously obtained at a liquid nitrogen temperature and a pressure of 1.5 MPa; at the same time, the adsorption column a is regenerated, and the regeneration process is as follows: first, the liquid nitrogen in the Dewar flask in which the low-temperature adsorption column a is located is pumped out to a liquid nitrogen tank, then high-purity nitrogen gas that is heated is used to purge the adsorption column a of the adsorption unit and the auxiliary pipelines, and finally, vacuumization is performed. After the regeneration of the adsorption column a is completed, the adsorption column a is purged and pressurized with 99.999% high-purity helium gas, liquid nitrogen is introduced into the low-temperature Dewar in which the adsorption column a is located for temperature balancing, and after the adsorption column b is saturated, the adsorption column a is switched back.

[0079] The above is only a few embodiments of the present application, and does not limit the present application in any form. Although the preferred embodiments are disclosed above, the present application is not limited thereto. Any person skilled in the art can make some changes or modifications to the disclosed technical content without departing from the scope of the technical solutions of the present application, and such changes or modifications are equivalent to equivalent embodiments, and are within the scope of the technical solutions.

Claims

1. A system for purifying helium from a multi-component gas mixture containing helium, characterized by, The system comprises a low-temperature cooling unit, a low-temperature adsorption unit and a helium product storage tank connected in sequence; The low-temperature cooling unit comprises a feeding system, a low-temperature Dewar I and a gas-liquid separator; The gas-liquid separator is in the low-temperature Dewar I; The low-temperature adsorption unit comprises a low-temperature Dewar II and an adsorption column; The adsorption column is in the low-temperature Dewar II; The multi-component mixed gas containing helium enters the gas-liquid separator through the feeding system for separation, the separated crude helium gas enters the adsorption column through a pipeline, and the helium product separated by the adsorption column enters the helium product storage tank.

2. The system of claim 1, wherein, The low-temperature adsorption unit comprises two parallel low-temperature adsorption units, which are denoted as low-temperature adsorption unit a and low-temperature adsorption unit b; The low-temperature adsorption unit a comprises a low-temperature Dewar IIa and an adsorption column a; The low-temperature adsorption unit b comprises a low-temperature Dewar IIb and an adsorption column b.

3. A method of purifying helium from a multi-component gas mixture containing helium, characterized by, The system of claim 1 or 2 is adopted; The method comprises the following steps: S1, using high-purity helium to purge and pressurize the entire system, and introducing liquid nitrogen into the low-temperature Dewar I and the low-temperature Dewar II; S2, the multi-component mixed gas containing helium enters the low-temperature Dewar I through the feeding system of the low-temperature cooling unit, is condensed and liquefied, and then is subjected to gas-liquid separation in the gas-liquid separator to obtain a liquid phase and a gas phase, and the gas phase is crude helium gas; S3, the crude helium gas enters the adsorption column of the low-temperature adsorption unit for adsorption separation, and the helium product separated by the adsorption column enters the helium product storage tank.

4. The method of claim 3, wherein, In step S3, two parallel low-temperature adsorption units are used; After the adsorption column a of the low-temperature adsorption unit a is saturated, the crude helium gas is switched into the adsorption column b of the low-temperature adsorption unit b for adsorption separation; At the same time of switching, the adsorption column a is regenerated, and after the regeneration of the adsorption column a, liquid nitrogen is introduced into the low-temperature Dewar IIa of the low-temperature adsorption unit a for temperature balance; after the adsorption column b is saturated, the crude helium gas is switched into the regenerated adsorption column a for adsorption separation, and at the same time of switching, the adsorption column b is regenerated.

5. The method according to claim 3 or 4, characterized in that, The operation is repeated.

6. The method according to any one of claims 3 to 5, characterized in that, In step S2, the multi-component mixed gas containing helium comprises He and impurity gas; The impurity gas comprises at least one of N2, Ar, H2, CO, CO2, Ne, O2 and CH4; The purity of the helium product separated is greater than 99.999%.

7. The method according to any one of claims 3 to 6, characterized in that, In step S2, the condensation and liquefaction pressure is 0.5-10 MPa.

8. The method according to any one of claims 3 to 7, characterized in that, In step S3, the adsorption separation pressure is 0.1-5 MPa.

9. The method according to any one of claims 3 to 8, characterized in that, The adsorption column is provided with an adsorbent, and the adsorbent is barium ion-exchanged molecular sieve.

10. The method according to any one of claims 3 to 9, characterized in that, The exchange degree of barium ions in the adsorbent is 50%-100%.

11. The method according to any one of claims 3 to 10, characterized in that, The molecular sieve is selected from at least one of LTA, FAU, MFI, BEA, MOR, CHA, EAB, AEL and TON topological structures.

12. The method according to any one of claims 3 to 11, characterized in that, The molecular sieve is selected from at least one of A, X, ZSM-5, Beta, MOR, SAPO-34, EAB, AlPO4-11 and ZSM-22.

13. The method according to any one of claims 3 to 12, characterized in that, The regeneration process comprises: First, the liquid nitrogen in the low-temperature Dewar bottle where the adsorption column a or b is located is discharged, then the adsorption column a or b and the associated pipelines of the low-temperature adsorption unit are purged by using the heated high-purity nitrogen gas, and finally, vacuum is drawn.

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