A multi-component mixed gas separation device integrating LNG cold energy utilization and its use method

Abstract

A multi-component mixed gas separation device and method for integrating LNG cold energy utilization is disclosed. The device consists of a feed inlet, a first cryogenic distillation column, a second cryogenic distillation column, and a heat exchanger, all interconnected by pipelines. The feed inlet is supplied with pronuclear waste gas. The rear of the feed inlet is connected to a shutoff valve inlet and a bypass valve inlet. The shutoff valve outlet is connected to the compressor inlet, the heat exchanger outlet, and the heat exchanger outlet, respectively. The compressor outlet is connected to the bypass valve outlet and the inlet of a buffer tank with a safety valve. The buffer tank outlet is connected to the hot end inlet of the first heat exchanger, which is then connected to the shutoff valve inlet. The shutoff valve outlet is connected to the feed inlet of a cryogenic dewar. Krypton and xenon are initially separated from the multi-component mixed gas by the cryogenic dewar, serving as feed gas for krypton-xenon separation. Cryogenic distillation is then used to separate krypton and xenon. The remaining mixed gas is pre-cooled with LNG and used as feed gas for helium and hydrogen (deuterium and tritium) separation. The distillation cooling is provided by a GM refrigerator.

Description

Technical Field

[0001] The present invention mainly relates to a multi-component mixed gas separation device integrated with LNG cold energy utilization and a use method thereof, and belongs to the field of air separation gas production. Background Art

[0002] In various nuclear fission reactions, byproducts are produced: ① gases such as krypton and xenon, ② a certain amount of hydrogen isotopes protium, deuterium, and tritium. Among them, krypton and xenon will absorb thermal neutrons in nuclear fission reactions, thus causing reactor poisoning; hydrogen isotope tritium produced at high temperatures can diffuse and penetrate through the reactor structural materials into the environment, causing pollution, and the decay products of tritium 3 He also causes helium embrittlement of reactor metal materials, affecting their mechanical properties. Therefore, it is necessary to separate and recycle the waste generated by nuclear reactions. Summary of the Invention

[0003] The present invention develops a multi-component mixed gas separation device and method for integrating LNG cold energy utilization, which separates He-based multi-component mixed gas components and recovers krypton, xenon, and hydrogen (deuterium and tritium), thereby reducing the pollution to the environment caused by nuclear waste gas emissions and recovering the economic value of the waste gas.

[0004] In order to achieve the purpose of the present invention, the present invention provides a multi-component mixed gas separation device for integrated LNG cold energy utilization, which consists of a raw material inlet end, a first low-temperature distillation tower, a second low-temperature distillation tower, and multiple heat exchangers, which are connected to each other through pipelines. The gas entering the raw material inlet end is proto-nuclear waste gas, and the rear of the raw material inlet end is respectively connected to the inlet of the stop valve A and the inlet of the bypass valve, wherein the outlet of the stop valve A is respectively connected to the inlet of the compressor, the outlet of the seventh heat exchanger, and the outlet of the eighth heat exchanger, and the outlet of the compressor is respectively connected to the outlet of the bypass valve and the inlet of the buffer tank with a safety valve, and the outlet of the buffer tank is connected to the The hot end inlet of the first heat exchanger, the hot end outlet of the first heat exchanger is connected to the inlet of the stop valve G, the outlet of the stop valve G is connected to the raw material inlet of the low-temperature Dewar, the cold end outlet of the first heat exchanger is connected to the inlet of the krypton-xenon stop valve, the outlet of the krypton-xenon stop valve is connected to the krypton-xenon filling cylinder, wherein a safety valve is arranged between the inlet of the krypton-xenon stop valve and the cold end outlet of the first heat exchanger, the cold end inlet of the first heat exchanger is connected to the outlet of the stop valve at the bottom outlet of the low-temperature Dewar, the inlet of the stop valve at the bottom outlet of the low-temperature Dewar is connected to the bottom outlet of the low-temperature Dewar, the bypass valve outlet, the compressor outlet, and the buffer tank inlet are all connected to the vacuum system with a vacuum stop valve.

[0005] Preferably, the low-temperature Dewar outlet is connected to the hot end inlet of the second heat exchanger, the hot end outlet of the second heat exchanger is connected to the raw material stop valve inlet of the first low-temperature distillation tower, the raw material stop valve outlet is connected to the raw material inlet of the first low-temperature distillation tower, the top exhaust port of the first low-temperature distillation tower is respectively connected to the stop valve H inlet and the second heat exchanger cold end inlet A, the second heat exchanger cold end outlet A is connected to the stop valve F inlet, the stop valve F outlet is connected to the third heat exchanger inlet, and the third heat exchanger outlet is connected to the helium filling cylinder.

[0006] Preferably, the outlet of the stop valve H is connected to the cold head inlet of the GM refrigerator, the cold head outlet of the GM refrigerator is connected to the return port of the first cryogenic distillation tower, the cold end inlet B of the second heat exchanger is connected to the outlet of the LNG stop valve, the inlet of the LNG stop valve and the inlet of the stop valve C are jointly connected to the LNG storage tank, the cold end outlet B of the second heat exchanger is connected to the cold source inlet of the condenser of the second cryogenic distillation tower, and the cold source inlet of the condenser of the second cryogenic distillation tower is also connected to the fourth heat exchanger, the inlet of the fourth heat exchanger is connected to the outlet of the stop valve C, the cold source outlet of the condenser is connected to the inlet of the fifth heat exchanger, and the outlet of the fifth heat exchanger is connected to the raw material inlet of the fuel cell, and the fuel cell transmits electrical energy to the system instrument electronic control through the voltage stabilizer.

[0007] Preferably, the bottom of the first cryogenic distillation tower is connected to the inlet of stop valve B, the outlet of stop valve B is connected to the inlet of the sixth heat exchanger, the outlet of the sixth heat exchanger is connected to the hydrogen (deuterium, tritium) filling cylinder, and an electric heating reboiler is also provided at the bottom of the first cryogenic distillation tower. The top of the second cryogenic distillation tower is connected to the bottom of the condenser, the exhaust port of the condenser is connected to the inlet of stop valve J, and the outlet of stop valve J is connected to the inlet of the seventh heat exchanger.

[0008] Preferably, the bottom outlet of the second cryogenic distillation tower is connected to the inlet of stop valve I, the outlet of stop valve I is connected to the inlet of the eighth heat exchanger, the krypton gas extraction port of the second cryogenic distillation tower is connected to the inlet of stop valve E, the outlet of stop valve E is connected to the inlet of the ninth heat exchanger, the outlet of the ninth heat exchanger is connected to the krypton gas filling cylinder, the xenon gas extraction port of the second cryogenic distillation tower is connected to the inlet of stop valve D, the outlet of stop valve D is connected to the inlet of the tenth heat exchanger, the outlet of the tenth heat exchanger is connected to the xenon gas filling cylinder, an electric heating reboiler is provided at the bottom of the second cryogenic distillation tower, the middle extraction port at the cold end of the first heat exchanger is connected to the inlet of the middle extraction stop valve K, and the outlet of the middle extraction stop valve K is connected to the raw material inlet of the second cryogenic distillation tower.

[0009] A method for using the above-mentioned multi-component mixed gas separation device integrated with LNG cold energy utilization, the method comprising:

[0010] 1) Preprocessing:

[0011] 2) Determine the flow path for the raw material waste gas to enter;

[0012] 3) The krypton-xenon gas produced is filled into the cylinder through the heat exchanger, valve and cryogenic distillation tower, hydrogen is flushed into the hydrogen cylinder, 4N krypton gas is filled into the krypton cylinder, and 5N high-purity xenon gas is filled into the xenon cylinder.

[0013] As a preference: the specific pretreatment method in step 1) is:

[0014] Before starting the system, vacuum must be drawn, and the bypass valve, stop valve A, stop valve B, stop valve D, stop valve E, stop valve F, LNG stop valve, and stop valve C must be closed. The remaining valves must be open, and the vacuum stop valve must be opened to start the vacuum system. When the pressure in the pipeline drops below 10 Pa, stop vacuuming, close the vacuum stop valve, and close all valves of the device of the present invention.

[0015] As a preferred method, the method for determining the flow of the raw material waste gas in step 2) is:

[0016] Determined based on the pressure of the raw waste gas: ① When the pressure of the raw waste gas is high, open the bypass valve and the raw waste gas enters the buffer tank; ② When the pressure of the raw waste gas is low, open the stop valve A, start the compressor, and the raw waste gas enters the buffer tank after being pressurized by the compressor. The buffer tank is equipped with a safety valve to prevent the buffer tank from overpressure.

[0017] As a preferred method, the specific method in step 3) is:

[0018] 1) Open the stop valve G, and the raw waste gas from the buffer tank passes through the first heat exchanger into the low-temperature dewar. In the low-temperature dewar, the krypton-xenon components in the raw waste gas are condensed into a slurry, in which the liquid krypton contains solid xenon. Open the stop valve, and the krypton-xenon slurry returns from the bottom of the low-temperature dewar to the cold end of the first heat exchanger to exchange heat with the raw waste gas from the buffer tank. After the heat exchange is balanced, the raw waste gas is pre-cooled, and the krypton-xenon slurry releases latent heat and absorbs and vaporizes. Open the krypton-xenon stop valve, and the krypton-xenon gas is reheated and filled into the cylinder. A safety valve is installed at the inlet of the krypton-xenon stop valve to prevent pipeline overpressure caused by the vaporization of the krypton-xenon slurry.

[0019] 2) Open the LNG shut-off valve, allowing LNG to enter the cold-end inlet B of the second heat exchanger. Simultaneously, open the raw material shut-off valve. The raw material waste gas exiting the cryogenic Dewar enters the first cryogenic distillation tower after being pre-cooled by LNG. Start the GM refrigerator and open the shut-off valve H. The raw material waste gas exiting the cryogenic Dewar is liquefied at the top of the first cryogenic distillation tower and accumulates at the bottom. Start the electric heating reboiler, and the accumulated liquid at the bottom of the first cryogenic distillation tower is evaporated. The distillation process in the first cryogenic distillation tower is established.

[0020] 3) After the distillation equilibrium is reached in the first cryogenic distillation tower, the opening of the stop valve H is reduced, and part of the exhaust gas from the top of the tower is used as the product 6N high-purity helium to enter the cold end inlet A of the second heat exchanger. The stop valve F is opened, and the product 6N high-purity helium participates in heat exchange and then passes through the third heat exchanger to be charged into the helium cylinder from the cold end outlet A of the second heat exchanger. The 6N high-purity helium product from the top of the first cryogenic distillation tower is pre-cooled with LNG to produce low-temperature Dewar raw material waste gas. The stop valve B is opened, and the liquid 4N hydrogen (deuterium and tritium) at the bottom of the first cryogenic distillation tower is charged into the hydrogen cylinder through the sixth heat exchanger;

[0021] 4) LNG exiting the cold end of the second heat exchanger passes through the condenser and the fifth heat exchanger into the fuel cell, generating electricity. After being stabilized by the pressure regulator, it is delivered to the power equipment in the device. It should be noted that LNG is split into two paths before entering the cold end of the second heat exchanger: ① One path enters the cold end inlet B of the second heat exchanger; ② When the stop valve C is opened, the LNG vaporizes through the fourth heat exchanger and merges with the cold end outlet BNG of the second heat exchanger at the condenser inlet.

[0022] 5) When further separation of the krypton-xenon mixed gas is required, the krypton-xenon stop valve is closed, and stop valve K is opened. Krypton-xenon liquid is pumped from the cold end of the first heat exchanger into the second cryogenic distillation tower. When the liquid accumulation at the bottom of the second cryogenic distillation tower reaches a specified value, the electric heating reboiler is turned on to evaporate the liquid accumulated at the bottom of the second cryogenic distillation tower. The vapor is partially condensed in the condenser and serves as reflux liquid. The cooling capacity of the condenser is provided by the low-temperature NG. When the distillation equilibrium of the second cryogenic distillation tower is reached, stop valve J is opened, and the exhaust gas at the top of the second cryogenic distillation tower is discharged through the seventh heat exchanger to the compressor inlet. Stop valve I is opened, and the effluent from the second cryogenic distillation tower is discharged through the eighth heat exchanger to the compressor inlet.

[0023] 6) Open stop valve E, and 4N krypton gas is charged into the krypton gas cylinder through the ninth heat exchanger. Open stop valve D, and 5N high-purity xenon gas is charged into the xenon gas cylinder through the tenth heat exchanger.

[0024] The present invention uses a cryogenic dewar to initially separate krypton and xenon from the diversified gas mixture, which serves as feed gas for krypton-xenon separation. Cryogenic distillation is then used to separate krypton and xenon. The remaining mixed gas is pre-cooled with LNG and used as feed gas for helium and hydrogen (deuterium and tritium) separation. The distillation cooling capacity is provided by a GM refrigerator. The cooling capacity for krypton-xenon separation is provided by cryogenic natural gas (NG). The reheated NG can be used in fuel cells, generating electricity that meets the power needs of the present invention's device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of the invention. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings: Figure 1As shown, a multi-component mixed gas separation device integrating LNG cold energy utilization is composed of a raw material inlet end, a first cryogenic distillation tower 13, a second cryogenic distillation tower 22, and a plurality of heat exchangers, which are connected to each other by pipelines. The gas entering the raw material inlet end is proto-nuclear waste gas, and the rear of the raw material inlet end is respectively connected to the inlet of the stop valve A1 and the inlet of the bypass valve 3, wherein the outlet of the stop valve A1 is respectively connected to the inlet of the compressor 2, the outlet of the seventh heat exchanger 27, and the outlet of the eighth heat exchanger 32, the outlet of the compressor 2 is respectively connected to the outlet of the bypass valve 3 and the inlet of the buffer tank 4 with a safety valve 5, and the outlet of the buffer tank 4 is connected to the hot end inlet of the first heat exchanger 8. The hot end outlet of the first heat exchanger 8 is connected to the inlet of the stop valve G44, the outlet of the stop valve G44 is connected to the raw material inlet of the low-temperature Dewar 9, the cold end outlet of the first heat exchanger 8 is connected to the inlet of the krypton-xenon stop valve 7, and the outlet of the krypton-xenon stop valve 7 is connected to the krypton-xenon filling cylinder, wherein a safety valve 6 is arranged between the inlet of the krypton-xenon stop valve 7 and the cold end outlet of the first heat exchanger 8, the cold end inlet of the first heat exchanger 8 is connected to the outlet of the low-temperature Dewar bottom outlet stop valve 10, and the inlet of the low-temperature Dewar bottom outlet stop valve 10 is connected to the bottom outlet of the low-temperature Dewar 9, the outlet of the bypass valve 3, the outlet of the compressor 2, and the inlet of the buffer tank 4 are all connected to the vacuum system with a vacuum stop valve.

[0027] The outlet of the low-temperature Dewar 9 is connected to the hot end inlet of the second heat exchanger 11, the hot end outlet of the second heat exchanger 11 is connected to the inlet of the raw material stop valve 12 of the first low-temperature distillation tower 13, the outlet of the raw material stop valve 12 is connected to the raw material inlet of the first low-temperature distillation tower 13, the top exhaust port of the first low-temperature distillation tower 13 is respectively connected to the inlet of the stop valve H16 and the cold end inlet A36 of the second heat exchanger 11, the cold end outlet A37 of the second heat exchanger 11 is connected to the inlet of the stop valve F41, the outlet of the stop valve F41 is connected to the inlet of the third heat exchanger 31, and the outlet of the third heat exchanger 31 is connected to the helium filling cylinder.

[0028] The outlet of the stop valve H16 is connected to the cold head inlet of the GM refrigerator 17, the cold head outlet of the GM refrigerator 17 is connected to the return port of the first low-temperature distillation tower 13, the cold end inlet B38 of the second heat exchanger 11 is connected to the outlet of the LNG stop valve 18, the inlet of the LNG stop valve 18 and the inlet of the stop valve C19 are jointly connected to the LNG storage tank, the cold end outlet B39 of the second heat exchanger 11 is connected to the cold source inlet of the condenser 21 of the second low-temperature distillation tower 22, and the cold source inlet of the condenser 21 of the second low-temperature distillation tower 22 is also connected to the fourth heat exchanger 20, the inlet of the fourth heat exchanger 20 is connected to the outlet of the stop valve C19, the cold source outlet of the condenser 21 is connected to the inlet of the fifth heat exchanger 40, and the outlet of the fifth heat exchanger 40 is connected to the raw material inlet of the fuel cell 34, and the fuel cell 34 transmits electrical energy to the system instrument electronic control through the regulator 35.

[0029] The bottom of the first cryogenic distillation tower 13 is connected to the inlet of the stop valve B15, the outlet of the stop valve B15 is connected to the inlet of the sixth heat exchanger 42, the outlet of the sixth heat exchanger 42 is connected to the hydrogen (deuterium, tritium) filling cylinder, and an electric heating reboiler 14 is also provided at the bottom of the first cryogenic distillation tower 13. The top of the second cryogenic distillation tower 22 is connected to the bottom of the condenser 21, the exhaust port of the condenser 21 is connected to the inlet of the stop valve J26, and the outlet of the stop valve J26 is connected to the inlet of the seventh heat exchanger 27.

[0030] The bottom outlet of the second cryogenic distillation tower 22 is connected to the inlet of the stop valve I24, the outlet of the stop valve I24 is connected to the inlet of the eighth heat exchanger 32, the krypton gas extraction port of the second cryogenic distillation tower 22 is connected to the inlet of the stop valve E28, the outlet of the stop valve E28 is connected to the inlet of the ninth heat exchanger 29, the outlet of the ninth heat exchanger 29 is connected to the krypton gas filling cylinder, the xenon gas extraction port of the second cryogenic distillation tower 22 is connected to the inlet of the stop valve D25, the outlet of the stop valve D25 is connected to the inlet of the tenth heat exchanger 30, the outlet of the tenth heat exchanger 30 is connected to the xenon gas filling cylinder, an electric heating reboiler 23 is provided at the bottom of the second cryogenic distillation tower 22, the extraction port at the cold end of the first heat exchanger 8 is connected to the inlet of the stop valve K33, and the stop valve K33 is connected to the raw material inlet of the second cryogenic distillation tower 22.

[0031] A method for using the above-mentioned multi-component mixed gas separation device integrated with LNG cold energy utilization, the method comprising:

[0032] 1) Preprocessing:

[0033] 2) Determine the flow path for the raw material waste gas to enter;

[0034] 3) The krypton-xenon gas produced is filled into the cylinder through the heat exchanger, valve and cryogenic distillation tower, hydrogen is flushed into the hydrogen cylinder, 4N krypton gas is filled into the krypton cylinder, and 5N high-purity xenon gas is filled into the xenon cylinder.

[0035] The specific pretreatment method in step 1) is:

[0036] Before starting the system, vacuum must be drawn. Close the bypass valve 3, stop valve A1, stop valve B15, stop valve D25, stop valve E28, stop valve F41, LNG stop valve 18, and stop valve C19. Open the remaining valves. Open the vacuum stop valve 43 and start the vacuum system. When the pressure in the pipeline drops below 10 Pa, stop vacuuming, close the vacuum stop valve 43, and close all valves of the device of the present invention.

[0037] The specific method for determining the flow of the raw material waste gas in step 2) is:

[0038] Determined according to the pressure of the raw waste gas: ① When the pressure of the raw waste gas is high, open the bypass valve 3 and the raw waste gas enters the buffer tank 4; ② When the pressure of the raw waste gas is low, open the stop valve A1, start the compressor 2, and the raw waste gas enters the buffer tank 4 after being pressurized by the compressor 2. The buffer tank 4 is equipped with a safety valve 5 to prevent the buffer tank 4 from overpressure.

[0039] The specific method in step 3) is:

[0040] 1) Open the stop valve G44, and the raw waste gas from the buffer tank 4 passes through the first heat exchanger 8 and enters the low-temperature dewar 9. In the low-temperature dewar 9, the krypton-xenon components in the raw waste gas are condensed into a slurry, wherein the liquid krypton contains solid xenon. Open the stop valve 10 at the bottom outlet of the low-temperature dewar, and the krypton-xenon slurry returns from the bottom of the low-temperature dewar 9 to the cold end of the first heat exchanger 8 to exchange heat with the raw waste gas from the buffer tank 4. After the heat exchange is balanced, the raw waste gas is pre-cooled, and the krypton-xenon slurry releases latent heat and absorbs and vaporizes. Open the krypton-xenon stop valve 7, and the reheated krypton-xenon gas is filled into the cylinder. A safety valve 6 is provided at the inlet of the krypton-xenon stop valve 7 to prevent pipeline overpressure caused by the vaporization of the krypton-xenon slurry.

[0041] 2) Open the LNG shut-off valve 18, allowing LNG to enter the cold-end inlet B38 of the second heat exchanger 11. Simultaneously, open the raw material shut-off valve 12, allowing the raw material waste gas exiting the cryogenic Dewar 9 to enter the first cryogenic distillation tower 13 after being pre-cooled by LNG. Start the GM refrigerator, open the shut-off valve H16, and the raw material waste gas exiting the cryogenic Dewar 9 is liquefied at the top of the first cryogenic distillation tower 13 and accumulated at the bottom. Start the electrically heated reboiler 14, and the accumulated liquid at the bottom of the first cryogenic distillation tower 13 is evaporated, thus establishing the distillation process in the first cryogenic distillation tower 13.

[0042] 3) After the distillation equilibrium is reached in the first cryogenic distillation tower 13, the opening of the stop valve H16 is reduced, and part of the exhaust gas from the top of the tower enters the cold end inlet A36 of the second heat exchanger 11 as the product 6N high-purity helium. The stop valve F41 is opened, and the product 6N high-purity helium participates in heat exchange and is then charged into the helium cylinder from the cold end outlet A37 of the second heat exchanger 11 through the third heat exchanger 31. The 6N high-purity helium product from the top of the first cryogenic distillation tower 13 is pre-cooled with LNG to produce the low-temperature Dewar 9 raw material waste gas. The stop valve B15 is opened, and the liquid 4N hydrogen (deuterium and tritium) at the bottom of the first cryogenic distillation tower 13 is charged into the hydrogen cylinder through the sixth heat exchanger 42;

[0043] 4) LNG exiting the cold-end outlet B39 of the second heat exchanger 11 passes through the condenser 21 and the fifth heat exchanger 40 and enters the fuel cell, generating electricity. The electricity is then stabilized by the pressure regulator 35 and delivered to the electrical equipment in the device. It should be noted that the LNG is split into two paths before entering the cold-end of the second heat exchanger 11: ① One path enters the cold-end inlet B38 of the second heat exchanger 11; ② Upon opening the shut-off valve C19, the LNG is vaporized through the fourth heat exchanger 20 and merges with the cold-end outlet B39NG of the second heat exchanger 11 at the inlet of the condenser 21.

[0044] When further separation of the krypton-xenon mixed gas is required, the krypton-xenon stop valve 7 is closed, the stop valve K33 is opened, and the krypton-xenon liquid is pumped from the cold end of the first heat exchanger 8 into the second cryogenic distillation tower 22. When the liquid accumulated at the bottom of the second cryogenic distillation tower 22 reaches a specified value, the electric heating reboiler 23 is opened to evaporate the liquid accumulated at the bottom of the second cryogenic distillation tower 22. The vapor is partially condensed in the condenser 21 and serves as reflux liquid. The cooling capacity of the condenser 21 is provided by the low-temperature NG. When the distillation equilibrium of the second cryogenic distillation tower 22 is reached, the stop valve J26 is opened, and the exhaust gas from the top of the second cryogenic distillation tower 22 is discharged through the seventh heat exchanger 27 to the inlet of the compressor 2. The stop valve I24 is opened, and the effluent from the second cryogenic distillation tower 22 is discharged through the eighth heat exchanger 32 to the inlet of the compressor 2.

[0045] 6 Open the stop valve E28, and 4N krypton gas is charged into the krypton gas cylinder through the ninth heat exchanger 29. Open the stop valve D25, and 5N high-purity xenon gas is charged into the xenon gas cylinder through the tenth heat exchanger 30.

[0046] The present invention integrates LNG cold energy utilization with a multi-component mixed gas separation device and method of use. Specifically, ① a booster is used to raise the mixed gas pressure to 1 MPa (A) and stabilize it in a buffer tank. ② A cryogenic dewar is then used to remove most of the krypton and xenon in the mixed gas (volume fraction of krypton and xenon <1%). A krypton-xenon slurry (140.7K) is discharged from the bottom of the cryogenic dewar and heat-exchanged with the pressurized mixed gas, pre-cooling the pressurized mixed gas. The krypton-xenon slurry (140.7K) pre-cools the pressurized mixed gas and then vaporizes. This slurry can be directly charged to a cylinder or used as feed gas for krypton-xenon separation. Cryogenic distillation is then used to separate the krypton and xenon, yielding 5N high-purity xenon and 4N krypton. ③ The mixed gas (volume fraction of krypton and xenon <1%) exiting the cryogenic dewar is used as feed gas for helium and hydrogen (deuterium and tritium) separation. The pre-cooling cold source for the mixed gas at the cryogenic dewar outlet is provided by reflux helium and LNG. After pre-cooling, the mixed gas (at 111.7K) enters a cryogenic distillation tower for separation of helium and hydrogen (deuterium and tritium). The distillation cold source is provided by a GM refrigerator. After cryogenic distillation, 6N helium and 4N hydrogen (deuterium and tritium) are obtained. The krypton-xenon separation cold source is provided by cryogenic NG. After reheating, the NG can be used in a fuel cell, generating electricity that meets the power needs of the device.

Claims

1. A multi-component mixed gas separation device integrated with LNG cold energy utilization, the device comprising a raw material gas inlet, a first cryogenic distillation tower (13), a second cryogenic distillation tower (22), and a plurality of heat exchangers, which are interconnected by pipelines, and is characterized by: The gas entering the raw material inlet end is proto-nuclear waste gas. The rear of the raw material inlet end is connected to the inlet of the stop valve A (1) and the inlet of the bypass valve (3), wherein the outlet of the stop valve A (1) is connected to the inlet of the compressor (2), the outlet of the seventh heat exchanger (27), and the outlet of the eighth heat exchanger (32), respectively. The outlet of the compressor (2) is connected to the outlet of the bypass valve (3) and the inlet of the buffer tank (4) with a safety valve (5), respectively. The outlet of the buffer tank (4) is connected to the inlet of the hot end of the first heat exchanger (8), and the outlet of the hot end of the first heat exchanger (8) is connected to the inlet of the stop valve G (44). The outlet of the stop valve G (44) is connected to the low-temperature The cold end outlet of the first heat exchanger (8) is connected to the inlet of the krypton-xenon stop valve (7), and the outlet of the krypton-xenon stop valve (7) is connected to the krypton-xenon filling cylinder, wherein a safety valve (6) is provided between the inlet of the krypton-xenon stop valve (7) and the cold end outlet of the first heat exchanger (8), the cold end inlet of the first heat exchanger (8) is connected to the outlet of the low-temperature Dewar bottom outlet stop valve (10), and the inlet of the low-temperature Dewar bottom outlet stop valve (10) is connected to the bottom outlet of the low-temperature Dewar (9), and the outlet of the bypass valve (3), the outlet of the compressor (2), and the inlet of the buffer tank (4) are all connected to a vacuum system with a vacuum stop valve.

2. The multi-component mixed gas separation device integrated with LNG cold energy utilization according to claim 1, characterized in that: The outlet of the low-temperature dewar (9) is connected to the hot end inlet of the second heat exchanger (11), the hot end outlet of the second heat exchanger (11) is connected to the inlet of the raw material stop valve (12) of the first low-temperature distillation tower (13), the outlet of the raw material stop valve (12) is connected to the raw material inlet of the first low-temperature distillation tower (13), the top exhaust port of the first low-temperature distillation tower (13) is respectively connected to the inlet of the stop valve H (16) and the cold end inlet A (36) of the second heat exchanger (11), the cold end outlet A (37) of the second heat exchanger (11) is connected to the inlet of the stop valve F (41), the outlet of the stop valve F (41) is connected to the inlet of the third heat exchanger (31), and the outlet of the third heat exchanger (31) is connected to the helium filling cylinder.

3. The multi-component mixed gas separation device integrated with LNG cold energy utilization according to claim 2, characterized in that: The outlet of the stop valve H (16) is connected to the cold head inlet of the GM refrigerator (17), and the cold head outlet of the GM refrigerator (17) is connected to the return port of the first low-temperature distillation tower (13). The cold end inlet B (38) of the second heat exchanger (11) is connected to the outlet of the LNG stop valve (18). The inlet of the LNG stop valve (18) and the inlet of the stop valve C (19) are connected to the LNG storage tank. The cold end outlet B (39) of the second heat exchanger (11) is connected to the cold source inlet of the condenser (21) of the second low-temperature distillation tower (22), and the cold source inlet of the condenser (21) of the second low-temperature distillation tower (22) is also connected to the fourth heat exchanger (20). The inlet of the fourth heat exchanger (20) is connected to the outlet of the stop valve C (19). The cold source outlet of the condenser (21) is connected to the inlet of the fifth heat exchanger (40). The outlet of the fifth heat exchanger (40) is connected to the raw material inlet of the fuel cell (34). The fuel cell (34) transmits electric energy to the system instrument electronic control through the voltage stabilizer (35).

4. The multi-component mixed gas separation device integrated with LNG cold energy utilization according to claim 1 is characterized in that: The bottom of the first cryogenic distillation tower (13) is connected to the inlet of the stop valve B (15), the outlet of the stop valve B (15) is connected to the inlet of the sixth heat exchanger (42), the outlet of the sixth heat exchanger (42) is connected to the hydrogen (deuterium, tritium) filling cylinder, and an electric heating reboiler (14) is also provided at the bottom of the first cryogenic distillation tower (13). The top of the second cryogenic distillation tower (22) is connected to the bottom of the condenser (21), the exhaust port of the condenser (21) is connected to the inlet of the stop valve J (26), and the outlet of the stop valve J (26) is connected to the inlet of the seventh heat exchanger (27).

5. The multi-component mixed gas separation device integrated with LNG cold energy utilization according to claim 1 is characterized in that: The bottom outlet of the second cryogenic distillation tower (22) is connected to the inlet of the stop valve I (24), and the outlet of the stop valve I (24) is connected to the inlet of the eighth heat exchanger (32). The krypton gas extraction port of the second cryogenic distillation tower (22) is connected to the inlet of the stop valve E (28), and the outlet of the stop valve E (28) is connected to the inlet of the ninth heat exchanger (29). The outlet of the ninth heat exchanger (29) is connected to the krypton gas filling cylinder. The xenon gas extraction port of the second cryogenic distillation tower (22) is connected to the inlet of the stop valve D (25), and the outlet of the stop valve D (25) is connected to the inlet of the tenth heat exchanger (30). The outlet of the tenth heat exchanger (30) is connected to the xenon gas filling cylinder. An electric heating reboiler (23) is provided at the bottom of the second cryogenic distillation tower (22). The middle extraction port of the cold end of the first heat exchanger (8) is connected to the inlet of the middle extraction stop valve K (33), and the outlet of the middle extraction stop valve K (33) is connected to the raw material inlet of the second cryogenic distillation tower (22).

6. A method for using the multi-component mixed gas separation device integrated with LNG cold energy utilization according to any one of claims 1 to 5, characterized in that: The method comprises: 1) Preprocessing: 2) Determine the flow path for the raw material waste gas to enter; 3) The krypton-xenon gas produced is filled into the cylinder through the heat exchanger, valve and cryogenic distillation tower, hydrogen is flushed into the hydrogen cylinder, 4N krypton gas is filled into the krypton cylinder, and 5N high-purity xenon gas is filled into the xenon cylinder.

7. The method according to claim 6, characterized in that: The specific pretreatment method in step 1) is: Before starting the system, it is necessary to evacuate the system, close the bypass valve (3), stop valve A (1), stop valve B (15), stop valve D (25), stop valve E (28), stop valve F (41), LNG stop valve (18), and stop valve C (19), and open the remaining valves. Open the vacuum stop valve (43) and start the vacuum system. When the pressure in the pipeline drops below 10 Pa, stop evacuating the system, close the vacuum stop valve (43), and close all valves of the device of the present invention.

8. The method according to claim 6, wherein: The specific method for determining the flow of the raw material waste gas in step 2) is: Determined based on the pressure of the raw waste gas: ① When the pressure of the raw waste gas is high, open the bypass valve (3) and the raw waste gas enters the buffer tank (4); ② When the pressure of the raw waste gas is low, open the stop valve A (1), start the compressor (2), and the raw waste gas is pressurized by the compressor (2) and enters the buffer tank (4). The buffer tank (4) is equipped with a safety valve (5) to prevent the buffer tank (4) from overpressure.

9. The method according to claim 6, wherein: The specific method in step 3) is: 1) Open the stop valve G (44), and the raw waste gas from the buffer tank (4) enters the low-temperature dewar (9) through the first heat exchanger (8). In the low-temperature dewar (9), the krypton-xenon components in the raw waste gas are condensed into slurry, wherein the liquid krypton contains solid xenon. Open the stop valve (10) at the bottom outlet of the low-temperature dewar, and the krypton-xenon slurry returns from the bottom of the low-temperature dewar (9) to the cold end of the first heat exchanger (8) to exchange heat with the raw waste gas from the buffer tank (4). After the heat exchange is balanced, the raw waste gas is pre-cooled, and the krypton-xenon slurry releases latent heat and absorbs and vaporizes. Open the krypton-xenon stop valve (7), and the krypton-xenon gas is reheated and filled into the cylinder. A safety valve (6) is provided at the inlet of the krypton-xenon stop valve (7) to prevent pipeline overpressure caused by the vaporization of the krypton-xenon slurry. 2) Open the LNG stop valve (18), and LNG enters the cold end inlet B (38) of the second heat exchanger (11). At the same time, open the raw material stop valve (12), and the raw material waste gas exiting the low-temperature dewar (9) enters the first low-temperature distillation tower (13) after being pre-cooled by LNG. Start the GM refrigerator, open the stop valve H (16), and the raw material waste gas exiting the low-temperature dewar (9) is liquefied at the top of the first low-temperature distillation tower (13) and accumulates at the bottom. Start the electric heating reboiler (14), and the accumulated liquid at the bottom of the first low-temperature distillation tower (13) is evaporated. The distillation process of the first low-temperature distillation tower (13) is established. 3) After the distillation equilibrium is reached in the first cryogenic distillation tower (13), the valve opening of the stop valve H (16) is reduced, and part of the exhaust gas at the top of the tower is used as the product 6N high-purity helium to enter the cold end inlet A (36) of the second heat exchanger (11). The stop valve F (41) is opened. The product 6N high-purity helium participates in the heat exchange and is then charged into the helium cylinder from the cold end outlet A (37) of the second heat exchanger (11) through the third heat exchanger (31). The product 6N high-purity helium at the top of the first cryogenic distillation tower (13) and LNG are pre-cooled together to produce the low-temperature Dewar (9) raw material waste gas. The stop valve B (15) is opened, and the liquid 4N hydrogen (deuterium, tritium) at the bottom of the first cryogenic distillation tower (13) is charged into the hydrogen cylinder through the sixth heat exchanger (42); 4) The LNG exiting the cold end outlet B (39) of the second heat exchanger (11) passes through the condenser (21) and the fifth heat exchanger (40) and enters the fuel cell (34), generating electrical energy. The LNG is then stabilized by the pressure regulator (35) and then delivered to the electrical equipment of the device. It should be noted that the LNG is divided into two paths before entering the cold end of the second heat exchanger (11): ① one path enters the cold end inlet B (38) of the second heat exchanger (11); ② the stop valve C (19) is opened, the LNG is vaporized through the fourth heat exchanger (20), and merges with the cold end outlet B (39) of the second heat exchanger (11) at the inlet of the condenser (21); 5) When it is necessary to further separate the krypton-xenon mixed gas, close the krypton-xenon stop valve (7), open the stop valve K (33), and draw the krypton-xenon liquid from the cold end of the first heat exchanger (8) into the second cryogenic distillation tower (22). When the liquid accumulated at the bottom of the second cryogenic distillation tower (22) reaches a specified value, open the electric heating reboiler (23), evaporate the liquid accumulated at the bottom of the second cryogenic distillation tower (22), and partially condense the steam in the condenser (21) as reflux liquid. The cooling capacity of the condenser (21) is provided by the low-temperature NG. When the distillation equilibrium of the second cryogenic distillation tower (22) is reached, open the stop valve J (26), and the exhaust gas at the top of the second cryogenic distillation tower (22) is converged to the inlet of the compressor (2) through the seventh heat exchanger (27). Open the stop valve I (24), and the discharge liquid of the second cryogenic distillation tower (22) is converged to the inlet of the compressor (2) through the eighth heat exchanger (32); 6) Open the stop valve E (28), and 4N krypton gas is charged into the krypton gas cylinder through the ninth heat exchanger (29). Open the stop valve D (25), and 5N high-purity xenon gas is charged into the xenon gas cylinder through the tenth heat exchanger (30).

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