A krypton-xenon depletion device

Abstract

This utility model relates to a krypton-xenon extraction device, belonging to the technical field of gas purification. The extraction device includes a krypton-xenon extraction system and a temperature control system. The krypton-xenon extraction system is housed in a krypton-xenon cold box, which contains a liquid oxygen adsorber, a distillation column, a liquid nitrogen condenser, and a metering tank. The upper outlet of the distillation column is connected to the inlet of the tube side of the liquid nitrogen condenser; the outlet of the tube side of the liquid nitrogen condenser is connected to the inlet of the metering tank; a reboiler is located at the bottom of the distillation column; the outlet of the reboiler is connected to a product storage tank. The temperature control system includes an expansion agent cold box; the expansion agent cold box contains a second heat exchanger, a third heat exchanger, and an expander. The second and third heat exchangers are connected by two pipes to form a circulation system, with the expander installed on one of the pipes. This utility model can concentrate krypton-xenon liquid product from liquid oxygen and also collect the byproduct liquid oxygen, achieving product diversification.

Description

Technical Field

[0001] This utility model relates to the technical field of gas purification, specifically to a krypton-depleted xenon extraction device. Background Technology

[0002] Krypton-xenon lean is an intermediate product containing krypton and xenon produced during gas purification. High-purity rare gases require purification techniques. Existing krypton-xenon lean extraction devices mainly use medium to large-scale air separation equipment. The extraction process typically involves drawing the feed liquid from the liquid oxygen or liquid air side and adding a krypton-xenon lean distillation column (or cold box). Because krypton and xenon have higher boiling points than oxygen and nitrogen, they condense in the liquid air at the bottom of the krypton-xenon distillation column and then enter the upper column with the liquid oxygen, becoming concentrated in the oxygen product at the top. Further distillation using multi-stage krypton-xenon distillation columns (such as a single-stage and dual-stage krypton-xenon distillation column) gradually separates the oxygen and krypton-xenon mixture, yielding krypton-lean (low-concentration krypton-xenon) or crude krypton (40%–80% krypton-xenon). The existing lean krypton xenon extraction units have three main drawbacks: (1) When the lean krypton xenon is in abnormal operation, it will affect the main distillation operation, causing fluctuations in the production of the air separation unit, increasing the complexity of operation, and relatively reducing safety and stability; (2) The later modification projects have high requirements for site conditions, usually requiring the unit to be close to the main cold box of the air separation unit. The air separation unit must be shut down during construction, which requires a large amount of modification to the original system, and the construction difficulty and technical requirements are high, resulting in a large construction cost; (3) The lean krypton xenon extraction unit usually converts excess liquid oxygen into oxygen as a byproduct and returns it to the original air separation unit, which reduces the liquid oxygen production and storage, and has an impact on the energy use structure of the enterprise. Utility Model Content

[0003] To address the problems of fluctuations, high on-site requirements, and inability to collect liquid oxygen as a byproduct in existing krypton-depleted xenon extraction devices, this invention provides a krypton-depleted xenon extraction device to solve these problems.

[0004] The technical solution of this utility model is as follows:

[0005] A krypton-xenon extraction device includes a krypton-xenon extraction system and a temperature control system. The krypton-xenon extraction system is housed in a krypton-xenon cold box, which contains a liquid oxygen adsorber, a distillation column, a liquid nitrogen condenser, and a metering tank. The feed inlet of the distillation column is connected to the liquid oxygen adsorber. The liquid nitrogen condenser has a tube side and a shell side, with refrigerant flowing in the shell side. The upper outlet of the distillation column is connected to the inlet of the tube side of the liquid nitrogen condenser. The outlet of the tube side of the liquid nitrogen condenser is connected to the inlet of the metering tank. A reboiler is located at the bottom of the distillation column. The outlet of the reboiler is connected to a product storage tank.

[0006] The temperature control system includes an expansion agent cold box; the expansion agent cold box is equipped with heat exchanger two, heat exchanger three and an expander, the heat exchanger two and heat exchanger three are connected by two pipes to form a circulation system, and the expander is installed on one of the pipes.

[0007] Furthermore, the temperature control system also includes a heat exchanger I housed within the krypton-xenon cold chamber. The top outlet of the liquid nitrogen condenser is connected to heat exchanger I via a pipe, allowing the evaporated nitrogen gas to be used as a cooling medium. An external nitrogen gas pipe passes sequentially through heat exchanger I and heat exchanger III, connecting to the jacket inlet of the reboiler. The jacket outlet of the reboiler is connected to the liquid nitrogen condenser via a pipe. External nitrogen gas is depressurized to a working pressure above 0.7 MPa via medium-pressure nitrogen, enters heat exchanger I for heat exchange, and then flows along the pipe into heat exchanger III for further heat exchange, eventually reaching the reboiler as a heat source. The nitrogen gas heated in the reboiler is cooled to liquid nitrogen, which is then used as a makeup liquid in the liquid nitrogen condenser as a coolant. Nitrogen gas escaping from the top of the liquid nitrogen condenser in heat exchanger I undergoes heat exchange and is discharged through nitrogen vent valve I.

[0008] Furthermore, the upper outlet of the distillation column is connected to a heat exchanger via a pipe, and some of the oxygen separated in the distillation column can also be used as a cold source to cool the heat exchanger; the oxygen after heat exchange is discharged through an oxygen vent valve.

[0009] Furthermore, the outlet of the metering tank is connected to the liquid oxygen storage tank; the liquid oxygen separated from the raw liquid oxygen has a high purity and can be recycled, stored, and sold as pure oxygen.

[0010] Furthermore, the metering tank is connected to the distillation column via a pipeline, and liquid oxygen enters the upper part of the distillation column as reflux liquid to participate in the distillation.

[0011] Furthermore, a quick-shut-off valve is installed on the inlet side of the liquid oxygen pump pipeline. The quick-shut-off valve can promptly disconnect the lean krypton xenon extraction unit from the air separation unit without adversely affecting the operation of the air separation system.

[0012] Furthermore, the expander is equipped with a blower brake, with an air filter at the inlet and a silencer at the outlet.

[0013] Furthermore, the top outlet of the liquid nitrogen condenser is connected to heat exchanger II via a pipe. Liquid nitrogen serves as the cold source for the liquid nitrogen condenser. After heat exchange with oxygen, it evaporates, and some nitrogen gas is drawn out from the top. After the cold energy is recovered at the nitrogen cold end of heat exchanger III, some of the nitrogen gas is released into the atmosphere, while most of the nitrogen gas enters the cold box of the expander as the expansion gas.

[0014] Furthermore, a heat exchanger is installed on the pipe connecting the outlet of the reboiler to the product storage tank. The lean krypton xenon obtained in the reboiler is further cooled before entering the product storage tank.

[0015] Furthermore, the second heat exchanger is also equipped with a second nitrogen vent valve.

[0016] The working principle of this invention is as follows: Liquid oxygen, pressurized by a liquid oxygen pump, is sent through a vacuum pipeline into a lean krypton xenon cold box and then into a liquid oxygen adsorber. The adsorber removes nitrous oxide and some hydrocarbons from the liquid oxygen. The purified liquid oxygen then enters a lean krypton xenon distillation column for further distillation. External nitrogen is depressurized to a working pressure above 0.7 MPa by a medium-pressure nitrogen pump, cooled to approximately -171°C by heat exchanger one, and then cooled again by heat exchanger three before entering a reboiler to provide heat for the liquid oxygen. This process evaporates and concentrates the liquid oxygen accumulated at the bottom of the distillation column, forming a lean krypton xenon product with a purity of not less than 700 ppm krypton and 120 ppm xenon. The lean krypton xenon liquid product is stored in a product storage tank. Most of the oxygen evaporated in the distillation column is condensed into liquid oxygen in a liquid nitrogen condenser and then enters a metering tank, where it can be used as a byproduct, pure oxygen. The nitrogen in the expander cold box is liquefied by the expander, providing a cooling source for heat exchangers two and three.

[0017] The beneficial effects of this utility model are as follows:

[0018] This invention enables the concentration of lean krypton xenon liquid product from liquid oxygen, while also collecting the byproduct liquid oxygen, thus diversifying the product range. A nitrogen expander is used to provide cooling for the entire unit, ensuring the high recovery rate of liquid oxygen in the lean krypton xenon unit and reducing the unit's requirements for on-site conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of this utility model.

[0021] In the diagram, 1-lean krypton-xenon cold box, 2-expander cold box, 3-distillation column, 4-liquid oxygen adsorber, 5-heat exchanger one, 6-liquid nitrogen condenser, 7-metering tank, 8-heat exchanger two, 9-heat exchanger three, 10-product storage tank, 11-expander, 12-liquid oxygen pump, 13-nitrogen vent valve one, 14-oxygen vent valve, 15-nitrogen vent valve two, 16-reboiler. Detailed Implementation

[0022] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0023] Example 1

[0024] A krypton-xenon extraction device includes a krypton-xenon extraction system and a temperature control system. The krypton-xenon extraction system is housed in a krypton-xenon cold box 1, which contains a liquid oxygen adsorber 4, a distillation column 3, a liquid nitrogen condenser 6, and a metering tank 7. The feed inlet of the distillation column 3 is connected to the liquid oxygen adsorber 4. The liquid oxygen adsorber 4 is connected to a liquid oxygen pump 12. The liquid nitrogen condenser 6 has a tube side and a shell side, with refrigerant flowing in the shell side. The upper outlet of the distillation column 3 is connected to the inlet of the tube side of the liquid nitrogen condenser 6. The outlet of the tube side of the liquid nitrogen condenser 6 is connected to the inlet of the metering tank 7. A reboiler 16 is located at the bottom of the distillation column 3. The outlet of the reboiler 16 is connected to a product storage tank 10.

[0025] The temperature control system includes an expansion agent cold box 2; the expansion agent cold box 2 is equipped with a second heat exchanger 8, a third heat exchanger 9 and an expander 11. The second heat exchanger 8 and the third heat exchanger 9 are connected by two pipes to form a circulation system, and the expander 11 is installed on one of the pipes.

[0026] Example 2

[0027] A krypton-xenon extraction device includes a krypton-xenon extraction system and a temperature control system. The krypton-xenon extraction system is housed in a krypton-xenon cold box 1. The krypton-xenon cold box 1 is equipped with a liquid oxygen adsorber 4, a distillation column 3, a liquid nitrogen condenser 6, and a metering tank 7. The outlet of the metering tank 7 is connected to a liquid oxygen storage tank, and the outlet of the metering tank 7 is also connected to the distillation column 3 via a pipeline. The inlet of the distillation column 3 is connected to the liquid oxygen adsorber 4. The liquid oxygen adsorber 4 is connected to a liquid oxygen pump 12, and a quick-closing valve is installed on the inlet side pipeline of the liquid oxygen pump 12. The liquid nitrogen condenser 6 has a tube side and a shell side. The refrigerant flows in the shell side; the upper outlet of the distillation column 3 is connected to the inlet of the tube side of the liquid nitrogen condenser 6; the outlet of the tube side of the liquid nitrogen condenser 6 is connected to the inlet of the metering tank 7; and the pipe passes through the liquid nitrogen condenser 6; a reboiler 16 is provided at the bottom of the distillation column 3; the outlet of the reboiler 16 is connected to the product storage tank 10, and a heat exchanger 9 is provided on the connecting pipe; the upper outlet of the distillation column 3 is connected to the heat exchanger 5 through a pipe, and some of the oxygen separated in the distillation column 3 can also be used as a cold source to cool the heat exchanger 5; the oxygen after heat exchange is discharged through the oxygen vent valve 14.

[0028] The temperature control system includes an expanding agent cold box 2; the expanding agent cold box 2 is equipped with a second heat exchanger 8, a third heat exchanger 9, and an expander 11. The second heat exchanger 8 and the third heat exchanger 9 are connected by two pipes to form a circulation system. The expander 11 is installed on one of the pipes. The expander 11 is braked by a fan. An air filter is installed at the inlet of the expander 11, and a silencer is installed at the outlet of the expander 11. The temperature control system also includes a first heat exchanger 5 installed in the depleted krypton xenon cold box 1. The top outlet of the liquid nitrogen condenser 6 is connected to the second heat exchanger 8 through a pipe. The top outlet of the liquid nitrogen condenser 6 is connected to the first heat exchanger 5 through a pipe. An external nitrogen pipe passes through the first heat exchanger 5 and the third heat exchanger 9 in sequence and is connected to the jacket inlet of the reboiler 16. The jacket outlet of the reboiler 16 is connected to the liquid nitrogen condenser 6 through a pipe. External nitrogen gas is depressurized to a working pressure of over 0.7 MPa via a medium-pressure nitrogen system. It then enters heat exchanger 5 for heat exchange, and subsequently flows through pipelines to heat exchanger 9 for further heat exchange. Finally, it reaches reboiler 16, serving as its heat source. The heated nitrogen gas in reboiler 16 is cooled to liquid nitrogen, which is then used as a makeup liquid in liquid nitrogen condenser 6 as a coolant. Nitrogen gas escaping from the top of liquid nitrogen condenser 6 in heat exchanger 5 undergoes heat exchange and is discharged through nitrogen vent valve 13. Heat exchanger 8 is also equipped with nitrogen vent valve 15.

[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A krypton-lean xenon extraction device, comprising a krypton-lean xenon extraction system and a temperature control system; characterized in that, The lean krypton xenon extraction system is housed in a lean krypton xenon cold box, which includes a liquid oxygen adsorber, a distillation column, a liquid nitrogen condenser, and a metering tank. The feed inlet of the distillation column is connected to the liquid oxygen adsorber, which is connected to a liquid oxygen pump. The liquid nitrogen condenser has a tube side and a shell side, with refrigerant flowing in the shell side. The upper outlet of the distillation column is connected to the inlet of the tube side of the liquid nitrogen condenser, and the outlet of the tube side of the liquid nitrogen condenser is connected to the inlet of the metering tank. A reboiler is located at the bottom of the distillation column, and its outlet is connected to a product storage tank. The temperature control system includes an expansion agent cold box; the expansion agent cold box is equipped with heat exchanger two, heat exchanger three and an expander, the heat exchanger two and heat exchanger three are connected by two pipes to form a circulation system, and the expander is installed on one of the pipes.

2. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, The temperature control system includes a heat exchanger 1 installed in a krypton-xenon cold box. The top outlet of the liquid nitrogen condenser is connected to the heat exchanger 1 by a pipe. An external nitrogen pipe passes through the heat exchanger 1 and the heat exchanger 3 in sequence and is connected to the jacket inlet of the reboiler. The jacket outlet of the reboiler is connected to the liquid nitrogen condenser by a pipe.

3. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, The upper outlet of the distillation column is connected to a heat exchanger via a pipe.

4. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, The outlet of the metering tank is connected to the liquid oxygen storage tank.

5. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, The metering tank and the distillation column are connected by a pipeline.

6. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, A quick-shut-off valve is installed on the inlet side of the liquid oxygen pump.

7. The krypton-poor xenon extraction device as described in claim 1, characterized in that, The expander is equipped with a blower brake, an air filter at the inlet, and a silencer at the outlet.

8. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, The top outlet of the liquid nitrogen condenser is connected to heat exchanger II via a pipe.

9. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, A heat exchanger is installed on the pipeline connecting the outlet of the reboiler to the product storage tank.

10. The krypton-depleted xenon extraction device as described in claim 1, characterized in that, The second heat exchanger is also equipped with a second nitrogen vent valve.

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