Helium purification device and method

Abstract

The invention discloses a helium purification device and method. The device comprises a crude helium extraction unit and a refined helium extraction unit, the crude helium extraction unit comprises a steam-water separation tower, a drying tower, a first adsorption tower and a first dehydrogenation tower which are connected in sequence, and a hydrogen storage alloy is arranged in the first dehydrogenation tower; the refined helium extraction unit comprises a first cold box, a second cold box, a first distillation tower, a third cold box, a second dehydrogenation tower, a second distillation tower and a second adsorption tower which are connected in sequence; cellulose source carbon aerogel is used as an adsorbent in the second dehydrogenation tower; in the crude helium extraction process, the hydrogen storage alloy is adopted for dehydrogenation, in the refined helium extraction process, the carbon-based adsorbent is adopted for dehydrogenation, hydrogen removal and secondary utilization are achieved in the mode that the hydrogen storage alloy and the carbon-based adsorbent are combined, gas high pressure and condensation low temperature are fully utilized in the process, and the energy consumption is reduced. Excessive energy secondary input and a heating process are not needed, and the process is safer and more reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of helium purification, and in particular to a helium purification device and method. Background Art

[0002] Helium is an indispensable strategic material for the development of national defense and high-tech industries. It is widely used in cutting-edge scientific research and high-end manufacturing due to its unique properties. Extraction from natural gas containing helium is currently the only industrial way for humans to obtain helium. The technologies used mainly include membrane separation, pressure swing adsorption, catalytic dehydrogenation and cryogenic distillation.

[0003] Among them, the crude helium obtained by membrane separation and pressure swing adsorption technology often contains a high concentration of hydrogen. The cryogenic distillation process can achieve high-purity helium purification, but its equipment occupies a large area and has high energy consumption, resulting in a significant increase in production costs. At present, the catalytic oxidation method is usually used to react hydrogen and oxygen to generate water to remove hydrogen, and finally the adsorption method or membrane separation is used to purify the helium. Due to the high hydrogen content in the tail gas, the amount of pure oxygen required is also high. The reaction of hydrogen and oxygen releases a lot of heat. In order to control the reaction temperature not to exceed the catalyst use temperature, a multi-stage reaction needs to be set up. The higher the hydrogen content, the more reaction levels there are. Hydrogen and oxygen are explosive. A complex control system needs to be set up to prevent the explosion risk. At the same time, hydrogen is converted into water, and the value of hydrogen is not effectively utilized; in addition, the catalytic oxidation technology relies on high-cost catalysts such as palladium and causes the loss of hydrogen resources, which undoubtedly increases production costs. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a helium purification device and method, which can solve the problems existing in dehydrogenation by catalytic oxidation method, does not require excessive secondary energy input and heating process, and the process is safer and more reliable.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, a helium purification device is provided, comprising a crude helium extraction unit and a refined helium extraction unit; the crude helium extraction unit comprises a steam-water separation tower, a drying tower, a first adsorption tower and a first dehydrogenation tower connected in sequence, and a hydrogen storage alloy is arranged in the first dehydrogenation tower; the refined helium extraction unit comprises a first cold box, a second cold box, a first distillation tower, a third cold box, a second dehydrogenation tower, a second distillation tower and a second adsorption tower connected in sequence, and a cellulose-derived carbon aerogel is used as an adsorbent in the second dehydrogenation tower.

[0007] In some embodiments of the present invention, two drying towers and two first adsorption towers are provided, the two drying towers are connected in parallel, and the two first adsorption towers are connected in parallel.

[0008] In some embodiments of the present invention, the adsorption bed in the first adsorption tower includes a lower activated carbon layer and an upper molecular sieve layer, and the lower activated carbon layer is arranged in multiple layers; the tops of the two first adsorption towers are connected by a pipeline so that the two first adsorption towers work alternately in parallel to achieve continuous operation of the system.

[0009] In some embodiments of the present invention, the crude helium exhaust pipeline of the crude helium extraction unit is connected to the first cold box of the refined helium extraction unit.

[0010] In some embodiments of the present invention, the hydrogen storage alloy of the first dehydrogenation tower includes one or more of AB5 rare earth series, AB2 TiMn series and AB Ti Fe series hydrogen storage alloys.

[0011] In some embodiments of the present invention, the condensed product outlet of the first distillation column is connected to the inlet of the second cold box, and the condensed product outlet of the second distillation column is connected to the inlet of the third cold box.

[0012] In some embodiments of the present invention, the first cold box, the second cold box and the third cold box are connected to a refrigeration cycle system, and the first cold box, the second cold box and the third cold box are cooled to a set temperature respectively by the refrigeration cycle system.

[0013] In some embodiments of the present invention, the refrigerant of the refrigeration cycle system also enters the second dehydrogenation tower to provide cold capacity for the cellulose-derived carbon aerogel in the second dehydrogenation tower to achieve hydrogen adsorption.

[0014] In a second aspect of the present invention, a helium purification method is provided, comprising:

[0015] The mixed natural gas enters the steam-water separation tower for primary water removal, and then enters the drying tower for secondary water removal to achieve complete water removal;

[0016] The gas after the secondary water removal passes through an adsorption tower to remove carbon dioxide and some hydrocarbons, and then enters the first dehydrogenation tower for a primary dehydrogenation treatment to remove some hydrogen and obtain crude helium;

[0017] After the crude helium is cooled once in the first cold box and twice in the second cold box, it enters the first distillation tower for primary distillation to remove some hydrocarbons; after the distilled gas is cooled three times in the third cold box, it enters the second dehydrogenation tower for secondary dehydrogenation to achieve complete removal of hydrogen;

[0018] The gas after the secondary dehydrogenation is distilled in the second distillation tower to completely remove hydrocarbons, and then enters the second adsorption tower for adsorption to completely remove nitrogen and obtain refined helium.

[0019] In some embodiments of the present invention, the condensed products of the first distillation tower and the second distillation tower enter the second cold box and the third cold box respectively for cold energy recovery.

[0020] One or more technical solutions of the present invention have the following beneficial effects:

[0021] (1) The present invention provides a helium purification device. In the process of crude helium extraction, a hydrogen storage alloy is used for dehydrogenation. In the process of refined helium extraction, a carbon-based adsorbent is used for dehydrogenation. By using a combination of hydrogen storage alloy and carbon-based adsorbent, hydrogen removal and secondary utilization are achieved. The process fully utilizes the high gas pressure and low condensation temperature, does not require excessive secondary energy input and heating process, and the process is safer and more reliable.

[0022] (2) The present invention provides a helium purification device with high helium recovery purity. Under the economic recovery rate, its recovery purity reaches more than 99%; in addition, the condensed product produced by the distillation tower is recycled to realize cold recovery, and the process is more energy-saving and efficient; the adsorption tower works alternately to realize the simultaneous adsorption and desorption, thereby ensuring the continuous operation of the equipment.

[0023] (3) The present invention provides a helium purification method. In the process of extracting crude helium, firstly, a steam-water separation tower and a drying tower are used to remove water from BOG gas, then two first adsorption towers are used to remove carbon dioxide and part of hydrocarbons, and finally, a first dehydrogenation tower is used to remove part of hydrogen to obtain crude helium. In the process of extracting refined helium, firstly, a first distillation tower is used to remove part of hydrocarbons, then a second dehydrogenation tower is used to completely remove hydrogen, then a second distillation tower is used to completely remove hydrocarbons, and finally, a second adsorption tower is used to completely remove nitrogen, thereby realizing refined helium extraction. By gradually purifying other components in natural gas, the purified alkanes and hydrogen can be recycled, which meets environmental benefits. At the same time, the entire process is relatively simple and can be used for large-scale helium production, which has certain economic benefits and is conducive to market popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a crude helium extraction unit in the helium purification device of the present invention;

[0025] Figure 2 It is a schematic diagram of a refined helium extraction unit in the helium purification device of the present invention.

[0026] In the figure: 1. crude helium extraction unit; 101. steam-water separation tower; 102. drying tower; 103. first adsorption tower; 104. first dehydrogenation tower; 105. first valve; 106. second valve; 107. third valve; 108. fourth valve; 109. fifth valve; 110. sixth valve; 111. seventh valve; 2. refined helium extraction unit; 201. first cold box; 202. second cold box; 203. first distillation tower; 204. third cold box; 205. second dehydrogenation tower; 206. second distillation tower; 207. second adsorption tower; 208. first expander; 209. second expander; 210. first compressor; 211. air cooler; 212. second compressor. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] Example 1

[0029] In a typical embodiment of the present invention, a helium purification device is provided, such as Figure 1 and Figure 2 As shown, it includes a crude helium extraction unit 1 and a refined helium extraction unit 2; the crude helium extraction unit 1 includes a steam-water separation tower 101, a drying tower 102, a first adsorption tower 103 and a first dehydrogenation tower 104 connected in sequence, and a hydrogen storage alloy is arranged in the first dehydrogenation tower 104; the refined helium extraction unit 2 includes a first cold box 201, a second cold box 202, a first distillation tower 203, a third cold box 204, a second dehydrogenation tower 205, a second distillation tower 206 and a second adsorption tower 207 connected in sequence, and cellulose-derived carbon aerogel is used as an adsorbent in the second dehydrogenation tower 205.

[0030] In this embodiment, the gas source for helium purification is BOG gas containing impurities such as hydrogen, oxygen, hydrocarbons, nitrogen, and carbon dioxide. The BOG gas first enters the steam-water separation tower 101, where most of the water in the BOG gas is removed, and then enters the drying tower 102. The drying tower 102 is provided with anhydrous silica gel, and water is completely removed by the action of the anhydrous silica gel. Two drying towers 102 are provided, and the two drying towers 102 are arranged in parallel.

[0031] In this embodiment, two first adsorption towers 103 are provided, and the two first adsorption towers 103 are connected in parallel. The tops of the two first adsorption towers 103 are connected by a pipeline, and a first valve 105 is provided on the connected pipeline, so that the two first adsorption towers 103 work alternately in parallel to achieve continuous operation of the system. There are many impurities entering the first adsorption tower, and the adsorption towers working alternately ensure that one tower works at high pressure, while the other tower desorbs at low pressure. In addition, the high-pressure gas of one tower can become a gas power source to drive the desorption of the other tower.

[0032] During operation, the first adsorption tower 103 adsorbs hydrocarbons and carbon dioxide. In comparison, these molecules are more non-polar and more easily adsorbed on activated carbon. Generally, adsorption can be achieved by activated carbon with a high specific surface area. At the same time, the adsorption selectivity of activated carbon can be achieved by adjusting the surface chemical properties of activated carbon, such as surface alkalinity, the number of surface functional groups, etc.

[0033] It is also because of this that helium, as an inert gas, and hydrogen, as a difficult-to-adsorb gas at room temperature, will pass through the adsorption tower without being absorbed. Therefore, through the adsorption tower, the hydrocarbons and carbon dioxide adsorbed in the tower are displaced through the van der Waals force, which requires a certain temperature or gas to achieve displacement. The helium under high pressure becomes the power source for displacement, driving out the hydrocarbons and carbon dioxide.

[0034] In this embodiment, the adsorption bed in the first adsorption tower 103 includes a lower activated carbon layer and an upper molecular sieve layer, wherein the activated carbon layer is mainly commercial coconut shell activated carbon, and the lower activated carbon layer is arranged in multiple layers. Preferably, the activated carbon layer is a three-layered structure, the particle size of the bottom bed layer is 10-30 mesh, the particle size of the middle bed layer is 30-60 mesh, and the upper layer is 60-80 mesh; the multi-layer design ensures the difference in bed pressure drop, thereby causing the difference in residence time of different beds, ensuring that the contact time of molecules with different polarities is different; the molecular sieve used in the upper molecular sieve layer is a mixture of 4A molecular sieve, mordenite molecular sieve, USY molecular sieve and 13X molecular sieve, and the specific ratio is 65-75:8-15:3-7:10-20.

[0035] The crude adsorption of hydrocarbons and carbon dioxide is achieved through the activated carbon layer, and the fine adsorption of hydrocarbons and carbon dioxide is achieved through the molecular sieve layer. At the same time, by setting the composition of molecular sieves with different ratios, from a macroscopic perspective, small molecular sieves can fill the gaps, increase the gas contact time, and prevent escape; at the same time, it helps to reduce costs; from a microscopic perspective, different molecular sieves have different adsorption capacities and adsorption selectivities, and a single molecular sieve is difficult to achieve the separation of multiple hydrocarbons. The composition of the molecular sieve is a molecular sieve with high hydrocarbon and carbon dioxide adsorption selectivity selected through experimental verification to ensure a better adsorption effect.

[0036] During the operation of the adsorption tower, the gas outlet valve at the top of the adsorption tower, namely the sixth valve 110 or the seventh valve 111, is kept closed to ensure the realization of the pressure swing adsorption process.

[0037] The hydrogen storage alloy of the first dehydrogenation tower 104 includes one or more of AB5 rare earth alloy, AB2 TiMn alloy and AB Ti Fe alloy. The hydrogen storage efficiency of the material in the first dehydrogenation tower 104 is as high as 15wt.%, the hydrogen storage working pressure is 5MPa, the dehydrogenation pressure is 0.05-2Mpa, and the number of cycles can reach more than 5000 times.

[0038] In this embodiment, the crude helium exhaust pipe of the crude helium extraction unit 1 is connected to the first cold box 201 of the refined helium extraction unit 2, so that the crude helium gas is cooled to 20°C in the first cold box 201 and then cooled to -120°C through the second cold box 202.

[0039] The crude helium after two coolings enters the first distillation tower 203 for distillation. After distillation, the helium and part of the hydrogen, nitrogen and part of the hydrocarbons enter the third cold box 204, are cooled to -150°C in the third cold box 204, and then enter the second dehydrogenation tower 205 for secondary dehydrogenation. Cellulose-derived carbon aerogel is used as an adsorbent in the second dehydrogenation tower 205. In actual applications, the working pressure in the second dehydrogenation tower 205 is 0.101 MPa, and the temperature in the second dehydrogenation tower is 77K. Carbon aerogel is used to achieve physical adsorption of hydrogen, which makes full use of the cold energy in the condensation process to achieve complete removal of hydrogen. The unit hydrogen storage capacity is more than 15wt.%, and it can desorb quickly to achieve secondary utilization of hydrogen.

[0040] The gas coming out of the second dehydrogenation tower 205 enters the second distillation tower 206 for secondary distillation after multi-stage pressure reduction to achieve complete removal of hydrocarbons. The condensed product of the second distillation tower 206 is liquid hydrocarbons, which enter the cold box cycle with the bottom product of the first distillation tower (liquid hydrocarbons) to achieve cold energy recovery.

[0041] Furthermore, the gas coming out of the second distillation tower 206 enters the interior of the second adsorption tower 207. A 13X molecular sieve is used inside the second adsorption tower 207. The molecular sieve has an adsorption selectivity of 100% for nitrogen. The nitrogen is completely removed by the second adsorption tower 207 to obtain helium with a purity of 99.999%. The product helium is connected to a helium storage tank for sealed transportation.

[0042] In this embodiment, the condensate product outlet of the first distillation tower 203 is connected to the inlet of the second cold box 202, and the condensate product outlet of the second distillation tower 206 is connected to the inlet of the third cold box 204, so as to realize the recovery of cold energy in the condensate product. The condensate product of the second distillation tower 206 enters the third cold box 204 for cold energy recovery, and then merges with the condensate product of the first distillation tower 203 and enters the second cold box 202 for cold energy recovery, and then enters the first cold box 201 for cold energy recovery, and finally is transported out for utilization through the second compressor 212.

[0043] In this embodiment, the first cold box 201, the second cold box 202 and the third cold box 204 use a conventional refrigeration cycle to reduce the temperatures to 20°, -120° and -150° respectively.

[0044] Specifically, the second dehydrogenation tower 205 is connected to the third cold box 204, the second cold box 202, the first cold box 201 and the air cooler 211 in sequence through pipelines to form a refrigerant circulation loop; the refrigerant circulation loop is provided with an expander and a compressor.

[0045] Furthermore, the expander includes a first expander 208 and a second expander 209, the first expander 208 is arranged between the third cold box 204 and the second dehydrogenation tower 205, the second expander 209 is arranged between the first cold box 201 and the air cooler 211; the first compressor 210 is arranged between the first cold box 201 and the second cold box 202.

[0046] The first cold box 201, the second cold box 202 and the third cold box 204 are cooled by the refrigerant circulation loop. The refrigerant of the refrigeration cycle system also enters the second dehydrogenation tower 205 to provide coldness for the cellulose-derived carbon aerogel in the second dehydrogenation tower 205 to achieve hydrogen adsorption.

[0047] The working principle of low-temperature pressure swing adsorption helium purification provided in this embodiment is:

[0048] The BOG gas containing impurities such as hydrogen, oxygen, hydrocarbons, nitrogen, carbon dioxide, etc. first enters the steam-water separation tower 101, and most of the water in the BOG gas is removed under the action of the steam-water separation tower 101, and then enters the drying tower 102. The drying tower 102 is provided with anhydrous silica gel, and the water is completely removed through the action of the anhydrous silica gel; under the action of the first adsorption tower 103, part of the hydrocarbons and carbon dioxide are removed, and then the BOG gas enters the first dehydrogenation tower 104 to remove part of the hydrogen; crude helium is obtained.

[0049] The crude helium containing hydrogen, hydrocarbons and nitrogen enters the first cold box 201 to be cooled to 20°C, then enters the second cold box 202 to be cooled to -120°, and then enters the first distillation tower 203 for distillation treatment to remove part of the hydrocarbons; then enters the second dehydrogenation tower 205 for dehydrogenation to achieve complete removal of hydrogen; the gas containing a small amount of hydrocarbons, nitrogen and helium coming out of the second dehydrogenation tower 205 enters the second distillation tower 206 for secondary distillation to remove the remaining hydrocarbons and achieve removal of hydrocarbons; the helium and nitrogen coming out of the second distillation tower 206 enter the second adsorption tower 207 to achieve removal of nitrogen, and obtain a product helium with a purity of 99.99%.

[0050] During the operation of the system, the two first adsorption towers 103 work alternately. Specifically, for example, when the adsorption tower on the left is working, the sixth valve 110 is closed to keep it in a high-pressure operation state, and the seventh valve 111 is opened to keep the adsorption tower on the right in a low-pressure state. At this time, part of the helium coming out of the left adsorption tower enters the top of the right adsorption tower through the first valve 105 to displace and desorb the fixed bed layer. At this time, the desorbed waste gas (hydrocarbons, carbon dioxide) is discharged through the third valve 107 and the fourth valve 108, and the second valve 106 is closed. When the adsorption tower on the right is working, the operation mode is opposite to the above situation.

[0051] At the same time, the seventh valve 111 remains open, and the gas containing nitrogen and hydrogen enters the first dehydrogenation tower 104 for dehydrogenation. During the hydrogen storage process in the first dehydrogenation tower 104, the fifth valve 109 remains closed, and the pressure in the tank is maintained above 5MPa; during the discharge of crude helium, the pressure is maintained between 2 and 5MPa, and this pressure ensures that hydrogen is not desorbed. After being processed by multiple pressure reducing valves, the helium is finely purified; in the hydrogen release process, the hydrogen storage alloy in the first dehydrogenation tower 104 is taken out, and the hydrogen is released and recycled by heating. During the heating process, the pressure is maintained between 0.05-2Mpa to completely displace the residual hydrogen in the hydrogen storage alloy.

[0052] During the operation of the system, the first cold box 201, the second cold box 202 and the third cold box 204 are cooled to 20°, -120° and -150° respectively through the refrigeration cycle formed by the first expander 208, the second expander 209, the first compressor 210 and the air cooler 211. In addition, the refrigerant in the refrigeration cycle also enters the second dehydrogenation tower 205 to provide coldness for the cellulose-derived carbon aerogel in the second dehydrogenation tower 205 to achieve hydrogen adsorption.

[0053] At the same time, the cold energy of the condensed products (liquid hydrocarbons) of the first distillation tower 203 and the second distillation tower 206 enters the cold box for recycling and is finally discharged from the system through the second compressor 212 .

[0054] Example 2

[0055] In a typical embodiment of the present invention, a helium purification method is provided. The helium purification device described in Example 1 comprises:

[0056] The mixed natural gas enters the steam-water separation tower for primary water removal, and then enters the drying tower for secondary water removal to achieve complete water removal;

[0057] The gas after the secondary water removal passes through an adsorption tower to remove carbon dioxide and some hydrocarbons, and then enters the first dehydrogenation tower for a primary dehydrogenation treatment to remove some hydrogen and obtain crude helium;

[0058] After the crude helium is cooled once in the first cold box and twice in the second cold box, it enters the first distillation tower for primary distillation to remove some hydrocarbons; after the distilled gas is cooled three times in the third cold box, it enters the second dehydrogenation tower for secondary dehydrogenation to achieve complete removal of hydrogen;

[0059] The gas after the secondary dehydrogenation is distilled in the second distillation tower to completely remove hydrocarbons, and then enters the second adsorption tower for adsorption to completely remove nitrogen and obtain refined helium.

[0060] Furthermore, the condensed products of the first distillation tower and the second distillation tower enter the second cold box and the third cold box respectively for cold energy recovery.

[0061] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A helium purification device, characterized in that: It comprises a crude helium extraction unit and a refined helium extraction unit; the crude helium extraction unit comprises a steam-water separation tower, a drying tower, a first adsorption tower and a first dehydrogenation tower connected in sequence, wherein a hydrogen storage alloy is arranged in the first dehydrogenation tower; the refined helium extraction unit comprises a first cold box, a second cold box, a first distillation tower, a third cold box, a second dehydrogenation tower, a second distillation tower and a second adsorption tower connected in sequence, wherein a cellulose-derived carbon aerogel is used as an adsorbent in the second dehydrogenation tower.

2. The helium purification device according to claim 1, characterized in that: The drying tower and the first adsorption tower are both provided with two, the two drying towers are connected in parallel, and the two first adsorption towers are connected in parallel.

3. The helium purification device according to claim 2, characterized in that: The adsorption bed in the first adsorption tower includes a lower activated carbon layer and an upper molecular sieve layer, and the lower activated carbon layer is arranged in multiple layers; the tops of the two first adsorption towers are connected by a pipeline so that the two first adsorption towers work alternately in parallel to realize continuous operation of the system.

4. The helium purification device according to claim 1, characterized in that: The crude helium exhaust pipeline of the crude helium extraction unit is connected to the first cold box of the refined helium extraction unit.

5. The helium purification device according to claim 1, characterized in that: The hydrogen storage alloy of the first dehydrogenation tower includes one or more of AB5 rare earth series, AB2 TiMn series and AB Ti Fe series hydrogen storage alloys.

6. The helium purification device according to claim 1, characterized in that: The condensed product outlet of the first distillation tower is connected to the inlet of the second cold box, and the condensed product outlet of the second distillation tower is connected to the inlet of the third cold box.

7. The helium purification device according to claim 1, characterized in that: The first cold box, the second cold box and the third cold box are connected to a refrigeration cycle system, and the first cold box, the second cold box and the third cold box are cooled to a set temperature respectively through the refrigeration cycle system.

8. The helium purification device according to claim 7, characterized in that: The refrigerant of the refrigeration cycle system also enters the second dehydrogenation tower to provide cold capacity for the cellulose-derived carbon aerogel in the second dehydrogenation tower to achieve hydrogen adsorption.

9. A helium purification method, using the helium purification device according to any one of claims 1 to 8, characterized in that: include: The mixed natural gas enters the steam-water separation tower for primary water removal, and then enters the drying tower for secondary water removal to achieve complete water removal; The gas after the secondary water removal passes through an adsorption tower to remove carbon dioxide and some hydrocarbons, and then enters the first dehydrogenation tower for a primary dehydrogenation treatment to remove some hydrogen and obtain crude helium; After the crude helium is cooled once in the first cold box and twice in the second cold box, it enters the first distillation tower for primary distillation to remove some hydrocarbons; after the distilled gas is cooled three times in the third cold box, it enters the second dehydrogenation tower for secondary dehydrogenation to achieve complete removal of hydrogen; The gas after the secondary dehydrogenation is distilled in the second distillation tower to completely remove hydrocarbons, and then enters the second adsorption tower for adsorption to completely remove nitrogen and obtain refined helium.

10. The helium purification method according to claim 9, characterized in that: The condensed products of the first distillation tower and the second distillation tower enter the second cold box and the third cold box respectively for cold energy recovery.

Images