A crude krypton-xenon re-purification device and method

Abstract

The present application relates to a kind of crude krypton-xenon purification device and method, specifically to a kind of crude krypton-xenon re-purification device and method, for solving the problem that the concentration of existing crude krypton-xenon product purification process is limited by the safety red line of methane concentration, which makes it difficult to further improve the concentration of product.The present application device includes first raw material supply device, first rectifying column, second rectifying column and second raw material supply device;Second rectifying column includes tower body and evaporator;First raw material supply device is used to supply crude krypton-xenon raw material liquid, its outlet is connected with first rectifying column;Second raw material supply device is used to supply low-temperature oxygen, its outlet is connected with first rectifying column;Krypton-xenon product outlet is connected with product storage device, for collecting the krypton-xenon product after purification.This method is used to distill crude krypton-xenon raw material liquid and raw material oxygen into intermediate product by first rectifying column;Second rectifying column evaporates methane in intermediate product, so that krypton-xenon component is further concentrated, so as to obtain the krypton-xenon product after purification.

Description

Technical Field

[0001] This invention relates to a crude krypton xenon purification apparatus and purification method, specifically to a crude krypton xenon re-purification apparatus and a method for re-purifying crude krypton xenon using the crude krypton xenon re-purification apparatus. Background Technology

[0002] Krypton (Kr) and xenon (Xe) are rare gases present in trace amounts in the air. Due to their unique physicochemical properties, they have significant applications in semiconductors, aerospace, lighting, and medical fields. Currently, industrially, krypton and xenon are mainly extracted from liquid air using large-scale air separation units. In the air separation process, krypton and xenon, as high-boiling-point components, are initially concentrated in a crude krypton-xenon column to obtain the crude krypton-xenon product.

[0003] However, the crude krypton-xenon product produced by existing air separation units contains a significant amount of impurities, primarily oxygen, argon, and methane, with xenon concentrations typically only reaching 150 ppm to 200 ppm. At this level, the methane concentration in the crude krypton-xenon product is already close to 3000 ppm. Since methane is a flammable and explosive component, further concentration in an oxygen-rich environment would cause the methane concentration to exceed safety limits, posing a serious safety risk.

[0004] Due to safety requirements for methane concentration control, existing processes are unable to deeply purify crude krypton-xenon feedstock, resulting in a bottleneck in increasing xenon product concentration: if concentration continues to increase krypton-xenon concentration, methane concentration will inevitably rise to dangerous levels simultaneously; if methane concentration is controlled within a safe range, krypton-xenon concentration cannot be further increased.

[0005] Due to the limited concentration of krypton xenon, the existing crude krypton xenon products have a narrow range of applications and low economic added value, making it difficult to meet the demand for high-purity krypton xenon products in fields such as semiconductors and aerospace propulsion. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problem that the concentration of krypton xenon products is difficult to further increase due to the safety limit of methane concentration in the existing crude krypton xenon product purification process, and to provide a crude krypton xenon re-purification device and method.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0008] A crude krypton xenon repurification device is characterized by comprising a first raw material supply device, a first distillation column, a second distillation column, and a second raw material supply device.

[0009] The first distillation column has a first raw material inlet at the top, a first waste gas outlet at the top, a second raw material inlet at the bottom, and an intermediate product outlet at the bottom; the first waste gas outlet is connected to a first pipeline.

[0010] The second distillation column includes a column body and an evaporator disposed within the column body and located at the bottom; the upper part of the column body has an intermediate product inlet, the top has a second waste gas outlet, and the bottom has a krypton-xenon product outlet; the second waste gas outlet is connected to a second pipe; the intermediate product inlet and the intermediate product outlet are connected to each other for introducing the intermediate product obtained after distillation in the first distillation column into the column body; the evaporator has an evaporation channel and a heat source channel, the evaporation channel being connected to the interior of the column body for evaporating the intermediate product;

[0011] The first raw material supply device is used to supply crude krypton xenon raw material liquid, and its outlet is connected to the first raw material inlet, for conveying the crude krypton xenon raw material liquid to the upper part of the first distillation column;

[0012] The second raw material supply device is used to supply low-temperature oxygen, and its outlet is connected to the inlet of the heat source channel and the second raw material inlet, respectively, to introduce low-temperature oxygen into the heat source channel and the lower part of the first distillation column;

[0013] The outlet of the heat source channel is connected to a third pipe, which extends to the outside of the tower body and is used to discharge the mixture of liquid oxygen and uncondensed oxygen obtained after the evaporator provides heat to the bottom of the tower body to the outside of the tower body.

[0014] The krypton-xenon product outlet is connected to a product storage device for collecting the purified krypton-xenon product.

[0015] Furthermore, it also includes a gas-liquid separator;

[0016] The gas-liquid separator has a gas outlet at the top and a liquid outlet at the bottom; the gas outlet is connected to a fourth pipe and the liquid outlet is connected to a fifth pipe.

[0017] The inlet of the gas-liquid separator is connected to the outlet of the third pipe, and is used to separate the mixture of liquid oxygen discharged from the evaporator and uncondensed oxygen into gas and liquid, so that the uncondensed oxygen is discharged from the gas outlet and the liquid oxygen is discharged from the liquid outlet.

[0018] Furthermore, it also includes heat exchangers;

[0019] The heat exchanger includes a first heat exchange channel and a second heat exchange channel; the outlet of the second heat exchange channel is connected to a sixth pipe.

[0020] The outlet of the second raw material supply device is connected to the inlet of the first heat exchange channel. The outlet of the first heat exchange channel is connected to the inlet of the heat source channel and the second raw material inlet, respectively, for passing low-temperature oxygen through the heat exchanger into the heat source channel of the evaporator and the lower part of the first distillation column.

[0021] The outlets of the first, second, and fourth pipes are respectively connected to the three inlets of a manifold tee. The outlet of the manifold tee is connected to the inlet of the second heat exchange channel, which is used to allow the exhaust gas to absorb heat in the second heat exchange channel, be heated to high temperature exhaust gas, and then be discharged through the sixth pipe.

[0022] Furthermore, it also includes cold boxes;

[0023] The first distillation column, the second distillation column, the gas-liquid separator, and the heat exchanger are all housed inside the cold box;

[0024] The first raw material supply device, the second raw material supply device, and the product storage device are all located outside the cold box;

[0025] The outlets of the fifth and sixth pipes are both located outside the cold box.

[0026] Furthermore, the product storage device is a vacuum storage tank.

[0027] Meanwhile, the present invention also provides a method for further purification of crude krypton xenon, which is characterized by including the following steps:

[0028] S1. Construct the above-mentioned crude krypton xenon re-purification device;

[0029] S2, Raw Material Supply

[0030] The crude krypton-xenon feedstock liquid is transported to the upper region of the first distillation column using a first feedstock supply device; at the same time, low-temperature oxygen is transported to the lower region of the first distillation column and the heat source channel of the evaporator using a second feedstock supply device.

[0031] S3, Preliminary Distillation

[0032] When the crude krypton-xenon feed liquid in the first distillation column comes into contact with low-temperature oxygen, mass and heat transfer occur, causing the low-boiling-point components to evaporate continuously and the high-boiling-point components to condense continuously. As a result, an intermediate product rich in krypton, xenon and some methane is obtained at the bottom of the column, and a gas rich in low-boiling-point impurities is obtained at the top of the column.

[0033] S4, Intermediate Product Conveying

[0034] The intermediate product obtained from the bottom of the first distillation column is sent to the upper part of the second distillation column through the intermediate product outlet and intermediate product inlet; and the gas rich in low-boiling-point impurities obtained from the top of the first distillation column is discharged through the first pipeline.

[0035] S5, Secondary Distillation

[0036] The intermediate products entering the second distillation column are collected at the bottom of the column; then they enter the evaporation channel of the evaporator, where they exchange heat with the low-temperature oxygen in the heat source channel, causing the low-temperature oxygen in the heat source channel to be further condensed into liquid oxygen, resulting in a mixture of liquid oxygen and uncondensed oxygen. This also causes the low-boiling-point impurities in the intermediate products in the evaporation channel to vaporize, thereby further concentrating the krypton-xenon components. Krypton-xenon products are obtained at the bottom of the column, and waste gas rich in low-boiling-point impurities is obtained at the top of the column.

[0037] S6, Product Collection

[0038] The krypton-xenon product obtained in step S5 is sent to the product storage device for collection via the krypton-xenon product outlet; the waste gas rich in low-boiling-point impurities is discharged through the second pipe; and the mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged through the third pipe, thus completing the repurification of crude krypton-xenon.

[0039] Furthermore, step S2 specifically includes:

[0040] The crude krypton-xenon feedstock liquid is transported to the upper region of the first distillation column using the first feedstock supply device;

[0041] Meanwhile, a second raw material supply device is used to transport low-temperature oxygen to the first heat exchange channel of the heat exchanger. After further condensation through heat exchange with the second heat exchange channel, it is transported to the lower part of the first distillation column and the heat source channel of the evaporator, respectively.

[0042] In step S6, the mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged through the third pipe. The specific method is as follows:

[0043] The mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged to the gas-liquid separator through the third pipe. The gas-liquid separator separates the mixture of liquid oxygen and uncondensed oxygen into uncondensed oxygen and liquid oxygen, which are discharged through the fourth pipe and the fifth pipe, respectively.

[0044] In steps S4 and S6:

[0045] The gas rich in low-boiling-point impurities discharged from the first pipe, the waste gas rich in low-boiling-point impurities discharged from the second pipe, and the uncondensed oxygen discharged from the fourth pipe are combined through a manifold tee to form a mixed gas. This mixed gas is then output to the second heat exchange channel of the heat exchanger as a cold source to exchange heat with the low-temperature oxygen in the first heat exchange channel, causing the low-temperature oxygen to condense further. The mixed gas itself is heated and then discharged through the sixth pipe for conventional oxygen recovery.

[0046] Furthermore, in step S2, the ratio of crude krypton-xenon feedstock liquid to low-temperature oxygen delivered to the first distillation column is 0.05~0.3.

[0047] Furthermore, in step S2, the ratio of crude krypton-xenon feedstock liquid to low-temperature oxygen delivered to the first distillation column is 0.1~0.18.

[0048] Furthermore, in step S6, the liquid oxygen discharged from the fifth pipe is collected outside the cold box;

[0049] In steps S4 and S6, the heated mixed gas discharged from the sixth pipe is collected outside the cold box.

[0050] Compared with the prior art, the present invention has the following beneficial technical effects:

[0051] 1. The present invention discloses a crude krypton-xenon repurification device, which first removes impurities such as oxygen and argon with low boiling points through a first distillation column, and then further removes low-boiling-point components such as methane through a second distillation column, forming a process architecture of dual-tower relay concentration. Under the premise of ensuring safe and controllable methane concentration, the xenon concentration in the crude krypton-xenon feed liquid can be significantly increased from 150ppm-200ppm to more than 1500ppm, and the krypton concentration can be significantly increased from 1800ppm to more than 9000ppm, thereby significantly improving the economic added value of the product.

[0052] 2. The present invention provides a crude krypton xenon repurification device, which separates the gas-liquid mixture discharged from the evaporator by setting a gas-liquid separator, so that the uncondensed oxygen can be recovered to participate in the system heat exchange, and the liquid oxygen is discharged independently, avoiding the impact of the gas-liquid two-phase mixing on the subsequent pipelines and heat exchangers, and improving the system operation stability.

[0053] 3. This invention provides a crude krypton-xenon repurification device. By incorporating a heat exchanger and utilizing distillation waste gas as a cold source, the device further condenses the low-temperature oxygen entering the system, recovering system cooling capacity and reducing external pre-cooling energy consumption. Simultaneously, the waste gas is heated to a high-temperature state before being discharged, facilitating safe emission without additional treatment. Furthermore, by integrating low-temperature equipment such as the first and second distillation columns, gas-liquid separator, and heat exchanger into a cold box, cold energy loss is reduced, and the insulation effect is improved. The raw material supply and product storage devices are located outside the cold box, facilitating operation, replenishment, and product retrieval. Additionally, a vacuum storage tank is used to collect the krypton-xenon product, utilizing vacuum insulation principles to maintain the product at a low temperature, reducing evaporation loss and ensuring stable product quality.

[0054] 4. The present invention provides a method for further purifying crude krypton xenon, which employs a dual-tower series cryogenic distillation process. The first distillation tower removes most of the low-boiling-point impurities such as oxygen and argon. The second distillation tower utilizes the heat provided by the further condensation and release of low-temperature oxygen in the evaporator to distill off residual low-boiling-point impurities such as methane. This process concentrates the krypton xenon components step by step, and the increase in the xenon concentration of the final product is no longer limited by the safety red line of methane concentration, achieving a dual breakthrough in safety and concentration efficiency.

[0055] 5. This invention provides a method for the repurification of crude krypton xenon, clarifying that the low-boiling-point impurities discharged from the top of the first distillation column are mainly oxygen and argon, facilitating subsequent targeted recovery and utilization or emission treatment of these waste gases. Simultaneously, it clarifies that the low-boiling-point impurities discharged from the top of the second distillation column are mainly methane, helping to understand the division of functions among the columns and facilitating process monitoring and safety control.

[0056] 6. The present invention provides a method for further purifying crude krypton xenon by using the combined waste gas as a cold source for a heat exchanger to further condense low-temperature oxygen, thereby recovering the cold energy of the device and reducing operating energy consumption; the waste gas is discharged after being heated for easy collection, and the liquid oxygen can also be recovered and reused separately.

[0057] 7. This invention provides a method for further purifying crude krypton xenon, which, while ensuring that the methane concentration does not exceed the safety limit of 3000 ppm, achieves a xenon concentration of over 1500 ppm and a krypton concentration of 9237 ppm. Compared to existing crude krypton xenon products (xenon concentration of approximately 150 ppm and krypton concentration of approximately 1893 ppm), this invention increases the xenon concentration by approximately 10 times and the krypton concentration by approximately 4 times. This breaks through the concentration bottleneck caused by methane enrichment in traditional crude krypton xenon purification, significantly improving the product's application range and economic added value. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the structure of a crude krypton-xenon repurification device according to Embodiment 1 of the present invention;

[0059] Figure 2 This is a schematic diagram of the structure of a crude krypton xenon repurification device according to Embodiment 2 of the present invention.

[0060] The attached figures are labeled as follows:

[0061] 1-First distillation column, 11-First raw material inlet, 12-First waste gas outlet, 13-Second raw material inlet, 14-Intermediate product outlet, 2-Second distillation column, 21-Column body, 22-Intermediate product inlet, 23-Second waste gas outlet, 24-Krypton-xenon product outlet, 3-Evaporator, 4-Gas-liquid separator, 41-Gas outlet, 42-Liquid outlet, 5-Product storage device, 6-Heat exchanger, 61-First heat exchange channel, 62-Second heat exchange channel, 7-Cold box, 81-First pipeline, 82-Second pipeline, 83-Third pipeline, 84-Fourth pipeline, 85-Fifth pipeline, 86-Sixth pipeline. Detailed Implementation

[0062] To make the objectives, advantages, and features of the present invention clearer, the following detailed description of a crude krypton-xenon repurification apparatus and method, in conjunction with the accompanying drawings and specific embodiments, is provided. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0063] This embodiment provides a crude krypton-xenon repurification device, used to concentrate the krypton-xenon components in the crude krypton-xenon feed solution, removing impurities such as oxygen, argon, and methane, so that the xenon concentration reaches above 1500 ppm, while controlling the methane concentration below 3000 ppm; Figure 1 As shown in the figure, the arrows indicate the direction of material flow, including the first raw material supply device, the first distillation column 1, the second distillation column 2, the second raw material supply device, the gas-liquid separator 4, the product storage device 5, the heat exchanger 6, and the cold box 7.

[0064] The first distillation column 1, the second distillation column 2, the gas-liquid separator 4, and the heat exchanger 6 are all located inside the cold box 7; the first raw material supply device, the second raw material supply device, and the product storage device 5 are all located outside the cold box 7.

[0065] The first distillation column 1 has a first raw material inlet 11 at the top, a first waste gas outlet 12 at the top, a second raw material inlet 13 at the bottom, and an intermediate product outlet 14 at the bottom; the first waste gas outlet 12 is connected to a first pipe 81, and the waste gas generated by distillation in the first distillation column 1 is discharged through the first pipe 81.

[0066] The second distillation column 2 includes a column body 21 and an evaporator 3 located at the bottom of the column body. The upper part of the column body 21 has an intermediate product inlet 22, a second waste gas outlet 23 at the top, and a krypton-xenon product outlet 24 at the bottom. The second waste gas outlet 23 is connected to a second pipe 82. The waste gas generated during distillation in the second distillation column 2 is discharged through the second pipe 82. The intermediate product inlet 22 is connected to the intermediate product outlet 14 and is used to introduce the intermediate product obtained after distillation in the first distillation column 1 into the upper part of the column body 21 of the second distillation column 2.

[0067] Evaporator 3 is equipped with an evaporation channel and a heat source channel. The evaporation channel is connected to the interior of column body 21 and is used to evaporate and discharge low-boiling-point impurities in the intermediate product at the bottom of the second distillation column 2, thereby rectifying the intermediate product in the second distillation column 2. Heat exchange occurs between the evaporation channel and the heat source channel through tube walls or plates. The low-temperature oxygen in the heat source channel absorbs heat from the liquid in the evaporation channel and further condenses, while the liquid in the evaporation channel releases heat, causing the low-boiling-point components to vaporize.

[0068] The first raw material supply device is used to supply crude krypton-xenon feedstock liquid. Its outlet is connected to the first raw material inlet 11, and it is used to transport the crude krypton-xenon feedstock liquid to the upper part of the first distillation column 1. In this embodiment, the first raw material supply device is a storage device that stores crude krypton-xenon feedstock liquid.

[0069] In other embodiments, the first raw material supply device may also be a pipeline for supplying crude krypton-xenon raw material liquid.

[0070] The heat exchanger 6 includes a first heat exchange channel 61 and a second heat exchange channel 62; the outlet of the second heat exchange channel 62 is connected to a sixth pipe 86; the sixth pipe 86 is used to extend to the outside of the cold box 7, so that the exhaust gas after heat exchange is collected outside the cold box 7.

[0071] The second raw material supply device is used to supply low-temperature oxygen (e.g., temperature range of 20℃~40℃, pressure of 0.1MPa~0.2MPa). Its outlet is connected to the inlet of the first heat exchange channel 61 of the heat exchanger 6. The outlet of the first heat exchange channel 61 is connected to the inlet of the heat source channel of the evaporator 3 and the second raw material inlet 13, respectively. It is used to further condense the low-temperature oxygen through the heat exchanger 6 and then pass it into the heat source channel of the evaporator 3 and the lower part of the first distillation column 1. The evaporator 3 is used to further condense the low-temperature oxygen entering it into a mixture of liquid oxygen and uncondensed oxygen. The heat released in this condensation process is used to heat the material in the second distillation column 2, so that the low-boiling point impurities (mainly methane) in the intermediate product are vaporized. In this embodiment, the second raw material supply device is a storage device that stores low-temperature oxygen.

[0072] In other embodiments, the second raw material supply device may also be a pipeline that continuously supplies cryogenic oxygen.

[0073] The outlet of the heat source channel of the evaporator 3 is connected to a third pipe 83, which extends to the outside of the tower body 21. The third pipe 83 is used to discharge the mixture of liquid oxygen and uncondensed oxygen obtained after the evaporator 3 provides heat to the bottom of the tower body 21 to the outside of the tower body 21.

[0074] The gas-liquid separator 4 has a gas outlet 41 at its top and a liquid outlet 42 at its bottom. The gas outlet 41 is connected to a fourth pipe 84, and the liquid outlet 42 is connected to a fifth pipe 85. The inlet of the gas-liquid separator 4 is connected to the outlet of the third pipe 83, used to separate the mixture of liquid oxygen and uncondensed oxygen discharged from the evaporator 3, allowing the uncondensed oxygen to exit from the gas outlet 41 and the liquid oxygen to exit from the liquid outlet 42. The fifth pipe 85, connected to the liquid outlet 42, extends to the outside of the cold box 7, facilitating the collection of the separated liquid from the gas-liquid separator 4 outside the cold box 7.

[0075] The heat exchanger 6 includes a first heat exchange channel 61 and a second heat exchange channel 62. The outlet of the second raw material supply device is connected to the inlet of the first heat exchange channel 61. The outlet of the first heat exchange channel 61 is connected to the inlet of the evaporator 3 and the second raw material inlet 13, respectively, for further condensation of low-temperature oxygen in the heat exchanger 6 before it is introduced into the evaporator 3 and the lower part of the first distillation column 1. The first waste gas outlet 12, the second waste gas outlet 23, and the gas outlet 41 are connected to the inlet of the second heat exchange channel 62 via a pipeline, for the waste gas to absorb heat in the second heat exchange channel 62, be heated to a high-temperature gas, and then discharged. The outlet of the second heat exchange channel 62 extends to the outside of the cold box 7 via a pipeline.

[0076] The outlets of the first pipe 81, the second pipe 82, and the fourth pipe 84 are respectively connected to the three inlets of a manifold tee. The outlet of the manifold tee is connected to the inlet of the second heat exchange channel 62, which is used to allow the exhaust gas to absorb heat in the second heat exchange channel 62, and after being heated to high temperature exhaust gas, it is discharged through the sixth pipe 86.

[0077] The krypton-xenon product outlet 24 is connected to a product storage device 5 for collecting the purified krypton-xenon product. In this embodiment, the product storage device 5 is a vacuum storage tank. The vacuum storage tank has a double-walled structure with a vacuum in the interlayer to achieve heat insulation and cold preservation.

[0078] The principle of this invention is as follows:

[0079] Employing a dual-tower distillation principle, the crude krypton-xenon feedstock utilizes the different boiling points of various impurity components. The first distillation column 1 removes lower-boiling-point impurities such as argon, oxygen, and some methane. The second distillation column 2 further removes methane and other impurities, ultimately yielding a concentrated krypton-xenon product. The evaporator 3 at the bottom of the second distillation column 2 utilizes the heat released from the further condensation of low-temperature oxygen as a heat source to drive the distillation process in the second distillation column 2.

[0080] This embodiment provides a method for further purifying crude krypton xenon, including the following specific steps:

[0081] S1. Construct the above-mentioned crude krypton xenon re-purification device. The specific structure is the same as above and will not be described in detail here.

[0082] S2, Raw Material Supply

[0083] The crude krypton-xenon feed liquid (analyzed by an analyzer, with a krypton concentration of 1893.38 ppm, a xenon concentration of 154.16 ppm, a methane concentration of 2963.35 ppm, and the remainder being impurities such as oxygen, nitrogen, and argon) is transported to the upper region of the first distillation column 1 using the first feed supply device.

[0084] Simultaneously, a second raw material supply device is used to deliver low-temperature oxygen to the lower region of the first distillation column 1 and the heat source channel of the evaporator 3; specifically:

[0085] A second raw material supply device supplies low-temperature oxygen (temperature 20℃~40℃, pressure 0.1MPa~0.2MPa) into the first heat exchange channel 61 of heat exchanger 6. After further condensation and heat exchange with waste gas in the second heat exchange channel 62, the oxygen is then delivered to the lower region of the first distillation column 1 and the heat source channel of the evaporator 3. The low-temperature oxygen can also originate from the oxygen pipeline in the air separation unit, with a purity ≥99.6%.

[0086] In this embodiment, the ratio of crude krypton xenon feedstock liquid to low-temperature oxygen delivered to the first distillation column 1 is 0.05~0.3 (this ratio can be further optimized to 0.1~0.18).

[0087] S3, Preliminary Distillation

[0088] When the crude krypton-xenon feedstock liquid in the first distillation column 1 comes into contact with low-temperature oxygen, mass and heat transfer occur, causing the low-boiling-point components to continuously evaporate and the high-boiling-point components to continuously condense. As a result, an intermediate product rich in krypton, xenon and some methane is obtained at the bottom of the column, and a gas rich in low-boiling-point impurities is obtained at the top of the column. The gas rich in low-boiling-point impurities mainly contains oxygen and argon.

[0089] Example of operating parameters: The top temperature of the first distillation column 1 is controlled at -177℃ to -174℃, the bottom temperature is controlled at -177℃ to -174℃, and the operating pressure is 0.05MPa to 0.15MPa. The temperature is controlled by adjusting the flow rate of cryogenic oxygen and / or the operating pressure of the first distillation column 1.

[0090] S4, Intermediate Product Conveying

[0091] The intermediate product obtained from the bottom of the first distillation column 1 is sent to the upper part of the second distillation column 2 through the intermediate product outlet 14 and the intermediate product inlet 22; and the gas rich in low-boiling-point impurities obtained from the top of the first distillation column 1 is discharged through the first pipe 81.

[0092] S5, Secondary Distillation

[0093] The intermediate product entering the second distillation column 2 collects at the bottom of column body 21; it then enters the evaporation channel of evaporator 3, where it exchanges heat with the low-temperature oxygen in the heat source channel of evaporator 3. This causes the low-temperature oxygen in the heat source channel of evaporator 3 to further condense into liquid oxygen, resulting in a mixture of liquid oxygen and uncondensed oxygen. Simultaneously, the low-boiling-point impurities in the intermediate product in the evaporation channel of evaporator 3 are vaporized, thereby further concentrating the krypton-xenon component. Krypton-xenon product is obtained at the bottom of column body 21, while a waste gas rich in low-boiling-point impurities is obtained at the top of column body 21. This waste gas rich in low-boiling-point impurities mainly contains methane.

[0094] Example of operating parameters: Top temperature of the second distillation column: -177℃~-175℃, bottom temperature: -177℃~-174℃.

[0095] S6, Product Collection

[0096] The krypton-xenon product obtained in step S5 (analyzed again by an analyzer, with a krypton concentration of 9237.70 ppm, a xenon concentration of 1528.56 ppm, and a methane concentration of 2901.30 ppm) is sent to product storage device 5 for collection via krypton-xenon product outlet 24; waste gas rich in low-boiling-point impurities is discharged through the second pipe 82; and the mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged through the third pipe 83. Specifically, the method for discharging the mixture of liquid oxygen and uncondensed oxygen in the heat source channel through the third pipe 83 is as follows:

[0097] The mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged to the gas-liquid separator 4 through the third pipe 83. The gas-liquid separator 4 separates the mixture of liquid oxygen and uncondensed oxygen into uncondensed oxygen and liquid oxygen, which are discharged through the fourth pipe 84 and the fifth pipe 85, respectively. The liquid oxygen discharged through the fifth pipe 85 is collected outside the cold box 7.

[0098] The xenon concentration in the krypton-xenon product reaches over 1500 ppm, while the methane concentration is controlled below 3000 ppm. The contents of krypton, xenon, and methane are shown in Table 1. Table 1 lists the contents of each key component in the crude krypton-xenon feedstock and the krypton-xenon product, respectively. While controlling the methane content to no more than 3000 ppm, the xenon concentration in the crude krypton-xenon feedstock was increased from 154 ppm to 1529 ppm.

[0099] Table 1. Schematic diagram of krypton, xenon, and methane content in krypton-xenon products.

[0100]

[0101] Note: The remaining components are impurities such as oxygen, nitrogen, and argon, which are not listed.

[0102] This invention uses the principle of cryogenic distillation to purify crude krypton-xenon feedstock while controlling the purity of methane.

[0103] In steps S4 and S6:

[0104] The gas rich in low-boiling-point impurities discharged from the first pipe 81, the waste gas rich in low-boiling-point impurities discharged from the second pipe 82, and the uncondensed oxygen discharged from the fourth pipe 84 are combined through a manifold tee to form a mixed gas (i.e., conventional oxygen). This mixed gas is then output to the second heat exchange channel 62 of the heat exchanger 6 as a cold source, where it exchanges heat with the low-temperature oxygen in the first heat exchange channel 61, causing the low-temperature oxygen to condense further. The mixed gas itself is heated and then discharged through the sixth pipe 86. The heated mixed gas discharged from the sixth pipe 86 is collected outside the cold box 7 (it can be recovered as conventional oxygen or directly vented).

[0105] This completes the re-purification of crude krypton xenon.

[0106] The above process has been subjected to extensive process simulation calculations, and the results show that the xenon concentration in the crude krypton xenon solution can be increased from 150 ppm to over 1500 ppm while controlling the methane concentration to no more than 3000 ppm.

[0107] Example 2

[0108] like Figure 2 As shown, the difference between this embodiment and embodiment 1 is that the gas-liquid separator 4 and the heat exchanger 6 are not provided.

[0109] The outlet of the second raw material supply device is directly connected to the inlet of the heat source channel of the evaporator 3 and the second raw material inlet 13, respectively, for directly introducing low-temperature oxygen into the heat source channel of the evaporator 3 and the lower part of the first distillation column 1.

[0110] After the third pipe 83 extends to the outside of the tower body 21, it extends directly to the outside of the cold box 7, so that the mixture of liquid oxygen and uncondensed oxygen obtained after the evaporator 3 provides heat to the bottom of the tower body 21 is discharged to the outside of the cold box 7 to collect the mixture of liquid oxygen and uncondensed oxygen.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A crude krypton-xenon repurification device, characterized in that: It includes a first raw material supply device, a first distillation column (1), a second distillation column (2), and a second raw material supply device; The first distillation column (1) is provided with a first raw material inlet (11) at the top, a first waste gas outlet (12) at the top, a second raw material inlet (13) at the bottom, and an intermediate product outlet (14) at the bottom; the first waste gas outlet (12) is connected to a first pipe (81); The second distillation column (2) includes a column body (21) and an evaporator (3) located inside the column body and at the bottom. The upper part of the column body (21) is provided with an intermediate product inlet (22), the top is provided with a second waste gas outlet (23), and the bottom is provided with a krypton-xenon product outlet (24). The second waste gas outlet (23) is connected to a second pipe (82). The intermediate product inlet (22) is connected to the intermediate product outlet (14) and is used to pass the intermediate product obtained after distillation of the first distillation column (1) into the column body (21). The evaporator (3) is provided with an evaporation channel and a heat source channel. The evaporation channel is connected to the interior of the column body (21) and is used for the evaporation of the intermediate product. The first raw material supply device is used to supply crude krypton xenon raw material liquid, and its outlet is connected to the first raw material inlet (11) to transport the crude krypton xenon raw material liquid to the upper part of the first distillation column (1); The second raw material supply device is used to supply low-temperature oxygen. Its outlet is connected to the inlet of the heat source channel and the second raw material inlet (13) respectively, and is used to introduce low-temperature oxygen into the heat source channel and the lower part of the first distillation column (1); The outlet of the heat source channel is connected to a third pipe (83), which extends to the outside of the tower body (21) to discharge the mixture of liquid oxygen and uncondensed oxygen obtained after the evaporator (3) provides heat to the bottom of the tower body (21) to the outside of the tower body (21). The krypton-xenon product outlet (24) is connected to a product storage device (5) for collecting the purified krypton-xenon product.

2. The crude krypton-xenon repurification apparatus according to claim 1, characterized in that: It also includes a gas-liquid separator (4); The gas-liquid separator (4) has a gas outlet (41) at the top and a liquid outlet (42) at the bottom; the gas outlet (41) is connected to a fourth pipe (84) and the liquid outlet (42) is connected to a fifth pipe (85). The inlet of the gas-liquid separator (4) is connected to the outlet of the third pipe (83) for gas-liquid separation of the mixture of liquid oxygen discharged from the evaporator (3) and uncondensed oxygen, so that the uncondensed oxygen is discharged from the gas outlet (41) and the liquid oxygen is discharged from the liquid outlet (42).

3. The crude krypton-xenon repurification apparatus according to claim 2, characterized in that: It also includes heat exchangers (6); The heat exchanger (6) includes a first heat exchange channel (61) and a second heat exchange channel (62); the outlet of the second heat exchange channel (62) is connected to a sixth pipe (86). The outlet of the second raw material supply device is connected to the inlet of the first heat exchange channel (61). The outlet of the first heat exchange channel (61) is connected to the inlet of the heat source channel and the second raw material inlet (13) respectively. It is used to further condense low-temperature oxygen through the heat exchanger (6) and then pass it into the heat source channel of the evaporator (3) and the lower part of the first distillation column (1). The outlets of the first pipe (81), the second pipe (82) and the fourth pipe (84) are respectively connected to the three inlets of a manifold tee. The outlet of the manifold tee is connected to the inlet of the second heat exchange channel (62), which is used to allow the waste gas to absorb heat in the second heat exchange channel (62), and after being heated to high temperature, it is discharged through the sixth pipe (86).

4. The crude krypton-xenon repurification apparatus according to claim 3, characterized in that: It also includes cold boxes (7); The first distillation column (1), the second distillation column (2), the gas-liquid separator (4) and the heat exchanger (6) are all installed inside the cold box (7); The first raw material supply device, the second raw material supply device, and the product storage device (5) are all located outside the cold box (7); The outlets of the fifth pipe (85) and the sixth pipe (86) are both located outside the cold box (7).

5. The crude krypton-xenon repurification apparatus according to claim 1, characterized in that: The product storage device (5) is a vacuum storage tank.

6. A method for further purifying crude krypton xenon, characterized in that, Includes the following steps: S1. Construct the crude krypton xenon repurification apparatus as described in any one of claims 1-5; S2, Raw Material Supply The crude krypton-xenon feedstock liquid is transported to the upper region of the first distillation column (1) using the first feedstock supply device; at the same time, the low-temperature oxygen is transported to the lower region of the first distillation column (1) and the heat source channel of the evaporator (3) using the second feedstock supply device. S3, Preliminary Distillation When the crude krypton-xenon feed liquid in the first distillation column (1) comes into contact with low-temperature oxygen, mass and heat transfer occurs, causing the low-boiling-point components to evaporate continuously and the high-boiling-point components to condense continuously, thereby obtaining an intermediate product rich in krypton, xenon and some methane at the bottom of the column and a gas rich in low-boiling-point impurities at the top of the column. S4, Intermediate Product Conveying The intermediate product obtained from the bottom of the first distillation column (1) is sent to the upper part of the second distillation column (2) through the intermediate product outlet (14) and the intermediate product inlet (22); and the gas rich in low-boiling-point impurities obtained from the top of the first distillation column (1) is discharged through the first pipe (81). S5, Secondary Distillation The intermediate products entering the second distillation column (2) are collected at the bottom of the column body (21); then they enter the evaporation channel of the evaporator (3) and exchange heat with the low-temperature oxygen in the heat source channel, so that the low-temperature oxygen in the heat source channel is further condensed into liquid oxygen, resulting in a mixture of liquid oxygen and uncondensed oxygen, and the low-boiling-point impurities in the intermediate products in the evaporation channel are vaporized, thereby further concentrating the krypton-xenon components, obtaining krypton-xenon products at the bottom of the column body (21), and obtaining waste gas rich in low-boiling-point impurities at the top of the column body (21); S6, Product Collection The krypton-xenon product obtained in step S5 is sent to the product storage device (5) for collection via the krypton-xenon product outlet (24); the waste gas rich in low-boiling-point impurities is discharged through the second pipe (82); and the mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged through the third pipe (83), thus completing the repurification of crude krypton-xenon.

7. The method for further purifying crude krypton xenon according to claim 6, characterized in that: Step S2 is as follows: The crude krypton-xenon feedstock liquid is transported to the upper region of the first distillation column (1) using the first raw material supply device; Meanwhile, a second raw material supply device is used to transport low-temperature oxygen to the first heat exchange channel (61) of the heat exchanger (6), and after further condensation through heat exchange with the second heat exchange channel (62), it is transported to the lower area of ​​the first distillation column (1) and the heat source channel of the evaporator (3), respectively. In step S6, the mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged through the third pipe (83). The specific method is as follows: The mixture of liquid oxygen and uncondensed oxygen in the heat source channel is discharged to the gas-liquid separator (4) through the third pipe (83). The gas-liquid separator (4) separates the mixture of liquid oxygen and uncondensed oxygen into uncondensed oxygen and liquid oxygen, which are discharged through the fourth pipe (84) and the fifth pipe (85) respectively. In steps S4 and S6: The gas rich in low-boiling-point impurities discharged from the first pipe (81), the waste gas rich in low-boiling-point impurities discharged from the second pipe (82), and the uncondensed oxygen discharged from the fourth pipe (84) are combined through a manifold tee to form a mixed gas. The mixed gas is then output to the second heat exchange channel (62) of the heat exchanger (6) as a cold source to exchange heat with the low-temperature oxygen in the first heat exchange channel (61), so that the low-temperature oxygen is further condensed. The mixed gas itself is heated and then discharged through the sixth pipe (86) as a conventional oxygen recovery.

8. The method for further purifying crude krypton xenon according to claim 6 or 7, characterized in that: In step S2, the ratio of crude krypton xenon feed liquid to low-temperature oxygen delivered to the first distillation column (1) is 0.05~0.

3.

9. The method for further purifying crude krypton xenon according to claim 8, characterized in that: In step S2, the ratio of crude krypton xenon feedstock liquid to low-temperature oxygen delivered to the first distillation column (1) is 0.1~0.

18.

10. The method for further purifying crude krypton xenon according to claim 7, characterized in that: In step S6, the liquid oxygen discharged from the fifth pipe (85) is collected outside the cold box (7); In steps S4 and S6, the heated mixed gas discharged from the sixth pipe (86) is collected outside the cold box (7).

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