Method and device for rectifying and purifying pure argon

Abstract

The invention relates to a method and a device for rectifying and purifying pure argon. The method comprises the following steps: carrying out primary rectification and secondary rectification on raw material crude argon; intermediate crude argon generated in the middle section of the first rectification is extracted to be used as a reboiling heat source of the second rectification, and the intermediate crude argon is liquefied into intermediate crude liquid argon to be used as reflux liquid of the first rectification. The device comprises a heat exchange rectification part, the heat exchange rectification part comprises a deoxidation tower for carrying out primary rectification, a denitrification tower for carrying out secondary rectification and a denitrification reboiler arranged at the bottom of the denitrification tower; the middle part of the deoxidation tower is provided with a crude argon outlet for extracting intermediate crude argon generated in the middle section of the first rectification and a crude liquid argon inlet for inputting intermediate crude liquid argon, the crude argon outlet of the deoxidation tower is connected with a gas inlet of the denitrification reboiler, and a liquid outlet of the denitrification reboiler is connected with the crude liquid argon inlet of the deoxidation tower. A reboiling heat source is provided for rectification denitrification in a thermal coupling mode, energy consumption is reduced, and product purity is improved.

Description

Technical Field

[0001] The invention relates to the technical field of gas purification, and in particular to a method and a device for purifying refined argon from crude argon gas by using a rectification method. Background Art

[0002] Argon is an inert gas that is widely used in various industries such as steel production, electronics industry, and machinery industry. The main method of obtaining argon in the world is to produce argon from air through cryogenic separation. Since the content of argon in the air is small, its separation process is much more difficult than oxygen and nitrogen separation. Therefore, argon is of high value and is an important by-product of cryogenic air separation equipment that mainly produces oxygen.

[0003] Taking crude argon from air separation tail gas as an example, at present, some air separation equipment does not produce argon, but only has a booster tower. The crude argon tail gas contains about 84% argon, about 2% nitrogen, and about 14% oxygen. After the crude argon tail gas is reheated through the main heat exchanger, these crude argon gases can only be discharged into the atmosphere or sent to a water-cooled tower, which cannot generate economic benefits and is a huge waste of gas resources. Argon-oxygen separation and argon-nitrogen separation are more difficult than oxygen-nitrogen separation, especially oxygen-argon separation, which is difficult to separate because the boiling point temperature difference is less than 3°C. In order to make the oxygen in argon reach the product requirement of 1.5PPm, the deoxidation tower requires a lot of theoretical plates. Also due to the boiling point difference and component balance, the deoxidation tower can only separate oxygen and argon, but not nitrogen at the same time. The removal of nitrogen in argon is achieved by the denitrification tower. However, the existing equipment combining the deoxidation tower and the denitrification tower still has the problem of high energy consumption, which makes the argon product cost high and the enterprise economic benefits low. Summary of the invention

[0004] The object of the present invention is to provide a method and device for purifying refined argon by distillation, which can reduce the required energy consumption, thereby reducing the cost and improving the economic benefit.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: A method for rectifying and purifying refined argon is used for rectifying raw material crude argon gas to obtain product liquid argon. The method for rectifying and purifying refined argon is as follows: S1: The raw material crude argon gas is subjected to a first distillation in a deoxygenation tower to remove at least part of the oxygen to obtain nitrogen-containing argon gas; during the first distillation process, intermediate crude argon gas is extracted from the middle section of the deoxygenation tower, and at least one of the raw material crude argon gas, nitrogen or air provided externally is introduced into a refrigeration cycle as a circulating medium, and the refrigeration cycle is used to provide a reboiling heat source and a condensation cold source for the first distillation, so that the raw material crude argon gas is fully contacted with the rising steam and the reflux in the deoxygenation tower to exchange heat and mass, and the nitrogen-containing argon gas is obtained at the top of the deoxygenation tower; S2: The nitrogen-containing argon gas is subjected to a second distillation in a denitrification tower to remove nitrogen and obtain the product liquid argon; during the second distillation process, the intermediate crude argon gas extracted from the middle section of the deoxygenation tower is used to provide a reboiling heat source for the second distillation, and the intermediate crude argon gas is liquefied into intermediate crude liquid argon after providing heat, and the intermediate crude liquid argon is sent back to the deoxygenation tower as a reflux liquid for the first distillation to participate in the distillation, and at the same time, the refrigeration cycle is used to provide a condensation cold source for the second distillation, so that the nitrogen-containing argon gas is fully in contact with the rising steam and reflux in the denitrification tower to exchange heat and mass, and the product liquid argon is obtained at the bottom of the denitrification tower.

[0006] The nitrogen-containing argon gas is subjected to hydrogenation catalysis to remove the remaining oxygen, purified to remove water, and then sent to the denitrification tower for a second distillation.

[0007] A device for rectifying and purifying refined argon, used for rectifying raw material crude argon gas to obtain product liquid argon, the device for rectifying and purifying refined argon comprises a heat exchange rectification part and a circulating refrigeration part; The heat exchange distillation part includes a deoxygenation tower and a denitrification tower; the deoxygenation tower is used to perform a first distillation on the raw material crude argon gas to remove oxygen to obtain nitrogen-containing argon gas; the denitrification tower is used to perform a second distillation on the nitrogen-containing argon gas to remove nitrogen to obtain the product liquid argon; A deoxygenation condenser is provided at the top of the deoxygenation tower, and a deoxygenation reboiler is provided at the bottom of the deoxygenation tower; The middle part of the deoxidation tower is provided with a crude argon outlet and a crude liquid argon inlet, the crude argon outlet is used to extract the intermediate crude argon generated in the middle section of the first distillation, and the crude liquid argon inlet is used to input the intermediate crude liquid argon; A denitrogenation condenser is provided at the top of the denitrogenation tower, and a denitrogenation reboiler is provided at the bottom of the denitrogenation tower; The denitrification reboiler has a gas inlet and a liquid outlet, the crude argon outlet of the deoxidation tower is connected to the gas inlet of the denitrification reboiler, the intermediate crude argon gas extracted from the middle section of the deoxidation tower is used as a reboiling heat source for the second distillation, the intermediate crude argon gas is liquefied into the intermediate crude liquid argon in the denitrification reboiler, the liquid outlet of the denitrification reboiler is connected to the crude liquid argon inlet of the deoxidation tower, and the intermediate crude liquid argon is input into the deoxidation tower as a reflux liquid for the first distillation; The circulating refrigeration part is used to carry out a refrigeration cycle to provide a reboiling heat source and a condensing cold source for the first distillation and a condensing cold source for the second distillation. The deoxygenation condenser, the deoxygenation reboiler and the denitrogenation condenser are connected to the circulating refrigeration part.

[0008] The heat exchange and distillation part also includes a crude argon compressor and a main heat exchanger, which are used to provide a raw gas source of the raw crude argon gas connected to the air inlet of the crude argon compressor, and the air outlet of the crude argon compressor is connected to the inlet of the first heat exchange pipeline in the main heat exchanger, and the outlet of the first heat exchange pipeline in the main heat exchanger is connected to the raw gas inlet of the deoxygenation tower. The nitrogen-containing argon gas outlet of the deoxygenation tower is respectively connected to the nitrogen-containing argon gas inlet of the denitrogenation tower and the gas inlet of the deoxygenation condenser, and the liquid outlet of the deoxygenation condenser is connected to the reflux liquid inlet of the deoxygenation tower. The nitrogen-containing dirty argon gas outlet of the denitrogenation tower is respectively connected to the gas inlet of the denitrogenation condenser and the nitrogen-containing dirty argon gas venting end, and the liquid outlet of the denitrogenation tower is connected to the reflux liquid inlet of the denitrogenation tower.

[0009] The circulating refrigeration part includes an air supply compressor, a circulating compressor and a subcooler, wherein the air outlet of the circulating compressor is connected to the inlet of the second heat exchange pipeline in the main heat exchanger, the outlet of the second heat exchange pipeline in the main heat exchanger is connected to the gas inlet of the deoxygenation reboiler, the liquid outlet of the deoxygenation reboiler is connected to the inlet of the first heat exchange pipeline in the subcooler, the outlet of the first heat exchange pipeline in the subcooler is respectively connected to the liquid inlet of the deoxygenation condenser and the liquid inlet of the denitrification condenser, and the gas outlet of the deoxygenation condenser is connected to the inlet of the second heat exchange pipeline in the subcooler The outlet of the second heat exchange pipeline in the subcooler is connected to the inlet of the third heat exchange pipeline in the main heat exchanger, the outlet of the third heat exchange pipeline in the main heat exchanger is connected to the air inlet of the circulation compressor, the gas outlet of the denitrification condenser is connected to the inlet of the third heat exchange pipeline in the subcooler, the outlet of the third heat exchange pipeline in the subcooler is connected to the inlet of the fourth heat exchange pipeline in the main heat exchanger, the outlet of the fourth heat exchange pipeline in the main heat exchanger is connected to the air inlet of the air supply compressor, and the air outlet of the air supply compressor is connected to the air inlet of the circulation compressor.

[0010] The circulating refrigeration part also includes a booster turbine expander, the air outlet of the circulating compressor is connected to the inlet of the booster end of the booster turbine expander, the outlet of the booster end of the booster turbine expander is connected to the inlet of the second heat exchange pipeline in the main heat exchanger, the outlet of the second heat exchange pipeline in the main heat exchanger is connected to the inlet of the expansion end of the booster turbine expander, and the outlet of the expansion end of the booster turbine expander is connected to the gas inlet of the deoxygenation reboiler.

[0011] The second heat exchange pipeline in the main heat exchanger also branches out a bypass outlet, and the bypass outlet is connected to the inlet of the first heat exchange pipeline in the subcooler.

[0012] The circulating refrigeration part also includes a liquefier, the liquid outlet of the denitrification condenser is connected to the inlet of the first heat exchange pipeline in the liquefier, the outlet of the second heat exchange pipeline in the liquefier is connected to the inlet of the third heat exchange pipeline in the subcooler, the evaporated argon gas outlet of the liquid argon tank for storing the product liquid argon is connected to the inlet of the second heat exchange pipeline in the liquefier, and the outlet of the second heat exchange pipeline in the liquefier is connected to the inlet of the liquid argon tank.

[0013] The device for rectifying and purifying refined argon further comprises a deoxygenation and dehydration system disposed between the crude argon outlet of the deoxygenation tower and the gas inlet of the denitrogenation reboiler, wherein the deoxygenation and dehydration system is used to remove oxygen and water from the nitrogen-containing argon gas; The deoxygenation and dehydration system comprises a catalytic system, a purification system, a hydrogen-rich compressor and a gas-liquid separator. The catalytic system comprises a hydrogenation pipeline for hydrogenation and deoxygenation, and the purification system is used for catalytic dehydration. The nitrogen-containing argon gas outlet of the deoxygenation tower is connected to the inlet of the catalytic system via the main heat exchanger, the outlet of the catalytic system is connected to the inlet of the purification system, the outlet of the purification system is connected to the inlet of the gas-liquid separator via the main heat exchanger, the liquid phase outlet of the gas-liquid separator is connected to the nitrogen-containing argon gas inlet of the denitrogenation tower, the gas phase outlet of the gas-liquid separator is connected to the inlet of the hydrogen-rich booster via the main heat exchanger, and the outlet of the hydrogen-rich booster is connected to the hydrogenation pipeline of the catalytic system.

[0014] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the present invention provides a reboiling heat source for distillation denitrogenation by thermal coupling, and does not need to introduce an external heat source, thereby reducing energy consumption. At the same time, the condensed liquid is used as a reflux liquid for distillation deoxygenation, which improves the separation efficiency and energy utilization efficiency of distillation deoxygenation, helps to optimize diversion or weighing, reduce energy consumption, and improve product purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 This is a schematic diagram of a device according to Embodiment 1 of the present invention.

[0016] Attached Figure 2 This is a schematic diagram of a device according to Embodiment 2 of the present invention.

[0017] Attached Figure 3 This is a schematic diagram of the device of Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0019] A method for distilling raw material crude argon to obtain product liquid argon to purify refined argon, which is achieved by combining deoxygenation distillation and denitrogenation distillation. The method for distilling and purifying refined argon is specifically: S1: The raw material crude argon gas is subjected to a first distillation in a deoxygenation tower to remove at least part of the oxygen to obtain nitrogen-containing argon gas; during the first distillation process, the intermediate crude argon gas is extracted from the middle section of the deoxygenation tower, and at least one of the raw material crude argon gas, nitrogen or air provided externally is introduced into the refrigeration cycle as a circulating medium, and the circulating medium passes through a specific heat exchange path and phase change process in the refrigeration cycle, and the refrigeration cycle is used to provide a reboiling heat source and a condensation cold source for the first distillation, so that the raw material crude argon gas is fully contacted with the rising steam and the reflux in the deoxygenation tower to exchange heat and mass, and the nitrogen-containing argon gas is obtained at the top of the deoxygenation tower; S2: The nitrogen-containing argon gas is subjected to a second distillation in the denitrification tower to remove nitrogen and obtain product liquid argon; in the second distillation process, the intermediate crude argon gas extracted from the middle section of the deoxygenation tower is used to provide a reboiling heat source for the second distillation, and the intermediate crude argon gas is liquefied into intermediate crude liquid argon after providing heat, and the intermediate crude liquid argon is sent back to the deoxygenation tower as the reflux liquid of the first distillation to participate in the distillation, and at the same time, a refrigeration cycle is used to provide a condensation cold source for the second distillation, so that the nitrogen-containing argon gas is fully in contact with the rising steam and reflux in the denitrification tower to exchange heat and mass, and the product liquid argon is obtained at the bottom of the denitrification tower.

[0020] In order to cope with the changes in the oxygen content in the raw crude argon gas of the first distillation and ensure that the intermediate crude argon gas produced in the middle section of the first distillation provides the temperature difference required for the reboiling heat source for the reboiler of the denitrogenation tower, different gas phase outlets and liquid phase reflux ports are set at different heights of the deoxygenation tower.

[0021] After the first distillation, the nitrogen-containing argon can be subjected to hydrogenation catalytic removal of residual oxygen, purification and water removal, and then sent to the denitrification tower for the second distillation. Specifically, the raw material crude argon is subjected to the first distillation to remove most of the oxygen, and the nitrogen-containing argon containing a small amount of remaining oxygen is reheated and first subjected to hydrogenation for oxygen removal, then purified and dehydrated, and then subjected to the second distillation. The hydrogen used for hydrogenation catalysis is recycled through a specific recovery and pressurization path, reducing the amount of external hydrogen supplementation.

[0022] The device for implementing the above-mentioned method of distillation and purification of refined argon is specifically as follows: Embodiment 1: As shown in the attached Figure 1 As shown, a device for distilling and purifying refined argon includes a heat exchange distillation part and a circulating refrigeration part.

[0023] The heat exchange and distillation part includes a deoxygenation tower C1, a denitrification tower C2, a deoxygenation condenser K3, a deoxygenation reboiler K1, a denitrification condenser K4, a denitrification reboiler K2, a crude argon compressor NC3 and a main heat exchanger E1. The deoxygenation tower C1 is used to perform the first distillation of the raw crude argon gas to remove oxygen to obtain nitrogen-containing argon gas, and the denitrification tower C2 is used to perform the second distillation of the nitrogen-containing argon gas to remove nitrogen to obtain product liquid argon. The front end of the deoxygenation tower C1 is connected to a gas source that provides raw crude argon gas, such as an air separation unit, and the rear end of the denitrification tower C2 is connected to a liquid argon tank / storage tank for storing product liquid argon. The deoxygenation condenser K3 is arranged at the top of the deoxygenation tower C1, which is used to provide reflux liquid for the deoxygenation tower C1. The deoxygenation reboiler K1 is arranged at the bottom of the deoxygenation tower C1, which is used to provide rising gas for the deoxygenation tower C1. The denitrogenation condenser K4 is arranged at the top of the denitrogenation tower C2, and is used to provide reflux liquid for the denitrogenation tower C2. The denitrogenation reboiler K2 is arranged at the bottom of the denitrogenation tower C2, and is used to provide rising gas for the denitrogenation tower C2. The deoxygenation tower C1 has the following multiple ports: a raw gas inlet located at its lower part, a nitrogen-containing argon outlet located at its top, a reflux liquid inlet located at its top, a crude argon outlet and a crude liquid argon inlet located in its middle part, wherein the crude argon outlet is used to extract the intermediate crude argon produced in the middle section of the first distillation, and the crude liquid argon inlet is used to input the intermediate crude liquid argon. The denitrogenation tower C2 has the following multiple ports: a nitrogen-containing argon inlet located at its upper part, a nitrogen-containing dirty argon outlet located at its top, and a reflux liquid inlet located at its top. The deoxygenation condenser K3 has the following multiple ports: a gas inlet, a liquid outlet, a liquid inlet, and a gas outlet. The deoxygenation reboiler K1 has the following multiple ports: a gas inlet and a liquid outlet. The denitrification condenser K4 has the following multiple ports: gas inlet, liquid outlet, liquid inlet, gas outlet. The denitrification reboiler K2 has the following multiple ports: gas inlet, liquid outlet. The crude argon compressor NC3 has an air inlet and an air outlet. The main heat exchanger E1 has multiple heat exchange pipelines numbered in sequence, and the subcooler E2 also has multiple heat exchange pipelines numbered in sequence.

[0024] The specific connection method of the heat exchange and distillation part is as follows: the raw gas source is connected to the air inlet of the crude argon compressor NC3, the air outlet of the crude argon compressor NC3 is connected to the inlet of the first heat exchange pipeline in the main heat exchanger E1, the outlet of the first heat exchange pipeline in the main heat exchanger E1 is connected to the raw gas inlet of the deoxygenation tower C1, the nitrogen-containing argon gas outlet of the deoxygenation tower C1 is divided into two paths and are respectively connected to the nitrogen-containing argon gas inlet of the deoxygenation tower C2 and the gas inlet of the deoxygenation condenser K3, the liquid outlet of the deoxygenation condenser K3 is connected to the reflux liquid inlet of the deoxygenation tower C1, the nitrogen-containing dirty argon gas outlet of the deoxygenation tower C2 is divided into two paths and are respectively connected to the gas inlet of the denitrogenation condenser K4 and the nitrogen-containing dirty argon gas venting end, and the liquid outlet of the denitrogenation tower C2 is connected to the reflux liquid inlet of the denitrogenation tower C2. The crude argon outlet of the deoxidation tower C1 is connected to the gas inlet of the denitrogenation reboiler K2, so that the intermediate crude argon is extracted from the middle of the deoxidation tower C1 and used as the reboiling heat source for the second distillation. The intermediate crude argon is liquefied into intermediate crude liquid argon in the denitrogenation reboiler K2, and the liquid outlet of the denitrogenation reboiler K2 is connected to the crude liquid argon inlet of the deoxidation tower C1, so that the intermediate crude liquid argon is input into the deoxidation tower C1 as part of the reflux liquid for the first distillation. In order to cope with the changes in the composition of the raw crude argon gas and ensure the temperature difference between the heat source and the denitrogenation reboiler K2, the deoxidation tower C1 needs to set its crude argon outlet and crude liquid argon inlet at an appropriate height position of the deoxidation tower C1.

[0025] The circulating refrigeration part is used to carry out the refrigeration cycle and provide the reboiling heat source and condensation cold source for the first distillation and the condensation cold source for the second distillation. The deoxygenation condenser K3, deoxygenation reboiler K1 and denitrification condenser K4 in the heat exchange distillation part are all connected to the refrigeration cycle of the circulating refrigeration part.

[0026] The circulating refrigeration part includes a supplementary air compressor NC1, a circulating compressor NC2, a booster turbine expander B-ETA and a subcooler E2. The gas outlet of the circulating compressor NC2 is connected to the inlet of the boosting end of the booster turbine expander B-ETA, the outlet of the boosting end of the booster turbine expander B-ETA is connected to the inlet of the second heat exchange pipeline in the main heat exchanger E1, a cooler WC1 can be arranged between the outlet of the boosting end of the booster turbine expander B-ETA and the inlet of the second heat exchange pipeline in the main heat exchanger E1, the outlet of the second heat exchange pipeline in the main heat exchanger E1 is connected to the inlet of the expansion end of the booster turbine expander B-ETA, and the outlet of the expansion end of the booster turbine expander B-ETA is connected to the gas inlet of the deoxygenation reboiler K1. At the same time, the second heat exchange pipeline in the main heat exchanger E1 also branches out a bypass outlet, and the bypass outlet is connected to the inlet of the first heat exchange pipeline in the subcooler E2. The liquid outlet of the deoxygenation reboiler K1 is also connected to the inlet of the first heat exchange pipeline in the subcooler E2. The outlet of the first heat exchange pipeline in the subcooler E2 is divided into two paths and respectively connected to the liquid inlet of the deoxygenation condenser K3 and the liquid inlet of the denitrification condenser K4. The gas outlet of the deoxygenation condenser K3 is connected to the inlet of the second heat exchange pipeline in the subcooler E2. The outlet of the second heat exchange pipeline in the subcooler E2 is connected to the inlet of the third heat exchange pipeline in the main heat exchanger E1. The outlet of the third heat exchange pipeline in 1 is connected to the air inlet of the circulation compressor NC2, the gas outlet of the denitrification condenser K4 is connected to the inlet of the third heat exchange pipeline in the subcooler E2, the outlet of the third heat exchange pipeline in the subcooler E2 is connected to the inlet of the fourth heat exchange pipeline in the main heat exchanger E1, the outlet of the fourth heat exchange pipeline in the main heat exchanger E1 is connected to the air inlet of the supplementary air compressor NC1, and the air outlet of the supplementary air compressor NC1 is connected to the air inlet of the circulation compressor NC2.

[0027] In addition, the circulating refrigeration part also includes a liquefier E3, the liquid outlet of the denitrification condenser K4 is connected to the inlet of the first heat exchange pipeline in the liquefier E3, the outlet of the second heat exchange pipeline in the liquefier E3 is connected to the inlet of the third heat exchange pipeline in the subcooler E2, the evaporated argon gas outlet of the liquid argon tank for storing product liquid argon is connected to the inlet of the second heat exchange pipeline in the liquefier E3, and the outlet of the second heat exchange pipeline in the liquefier E3 is connected to the inlet of the liquid argon tank.

[0028] In the circulating refrigeration part, from the perspective of energy consumption, using crude argon as the circulating medium is the most energy-saving. From a process perspective, air, argon, and nitrogen can all be used as the circulating medium. This embodiment takes air as an example.

[0029] The bottom of the deoxygenation tower C1 also has an oxygen-containing dirty argon gas outlet, which is connected to the inlet of the fifth heat exchange pipeline in the main heat exchanger E1, and the outlet of the fifth heat exchange pipeline in the main heat exchanger E1 is connected to the venting end of the oxygen-containing dirty argon gas. One branch of the nitrogen-containing dirty argon gas outlet of the denitrification tower C2 is connected to the inlet of the fourth heat exchange pipeline in the subcooler E2, and the outlet of the fourth heat exchange pipeline in the subcooler E2 is connected to the inlet of the sixth heat exchange pipeline in the main heat exchanger E1, and the outlet of the sixth heat exchange pipeline in the main heat exchanger E1 is connected to the venting end of the nitrogen-containing dirty argon gas.

[0030] The process flow of the above-mentioned device for rectifying and purifying refined argon to rectify the raw material crude argon gas to obtain the product liquid argon is as follows: the raw material crude argon gas from the air separation unit is compressed to a certain pressure by the crude argon compressor NC3 and then sent to the main heat exchanger E1. In the main heat exchanger E1, the raw material crude argon gas is heat exchanged with the reflux exhaust gas and circulating air. The raw material crude argon gas is cooled to about the saturation temperature and enters the lower part of the deoxidation tower C1. In the deoxidation tower C1, the raw material crude argon gas is repeatedly heat and mass exchanged with the reflux liquid flowing down from the top of the deoxidation tower C1 in the tower, so that nitrogen-containing argon gas with an oxygen content of less than 1.5 ppm is obtained at the top of the deoxidation tower C1. A part of the nitrogen-containing argon gas drawn out from the top of the deoxidation tower C1 is drawn out as the rising steam of the deoxidation tower C2, and the rest of the nitrogen-containing argon gas is condensed by liquid air in the deoxidation condenser K3, and then returned to the top of the deoxidation tower C1 as the reflux liquid of the deoxidation tower C1 to maintain the rectification condition of the deoxidation tower C1. A stream of oxygen-containing dirty argon gas with high oxygen content is drawn out from the bottom of the deoxygenation tower C1 for reheating and venting. In the deoxygenation reboiler K1, the air expanded at the expansion end of the booster turbine expander B-ETA is used as its heat source to vaporize the crude liquid argon at the bottom of the deoxygenation tower C1 and provide a part of the rising gas of the deoxygenation tower C1, thereby improving the distillation capacity of the deoxygenation tower C1. The air in the deoxygenation reboiler K1 is supercooled after condensation, and a part of it is throttled to enter the deoxygenation condenser K3 as a cold source. This part of the liquid air is vaporized in the deoxygenation condenser K3, and then reheated to room temperature through the main heat exchanger E1 and sent to the circulating compressor NC2.

[0031] The nitrogen-containing argon gas with an oxygen content of less than 1.5 ppm obtained from the top of the deoxygenation tower C1 is introduced from the upper part of the deoxygenation tower C2. A stream of nitrogen-containing dirty argon gas with a high nitrogen content is drawn out from the top of the deoxygenation tower C2 and then discharged after reheating. The deoxygenation reboiler K2 adopts a thermal coupling method. The heat source of the deoxygenation reboiler K2 is taken from a stream of crude argon gas drawn out from the lower part of the deoxygenation tower C1 according to the temperature difference, so that the liquid argon at the bottom of the deoxygenation tower C2 is vaporized to provide the rising gas of the deoxygenation tower C2. Thermal coupling is achieved between the deoxygenation tower C1 and the deoxygenation tower C2, that is, a reboiling heat source for the deoxygenation tower C2 is provided, and there is no need to introduce an external heat source, thereby reducing the energy consumption of the circulating machine. After the gas of the deoxygenation tower C1 is condensed and liquefied by the deoxygenation reboiler K2, it can return to the deoxygenation tower C1 as a reflux liquid, thereby improving the distillation capacity of the deoxygenation tower C1. The cold source of the denitrification condenser K4 is provided by another part of the liquid air throttling after being supercooled by the subcooler E2. This part of the throttled liquid air is vaporized by the denitrification condenser K4, and then reheated to room temperature by the main heat exchanger E1 and enters the air supply compressor NC1 for compression, and then enters the circulation compressor NC2. Qualified liquid argon products are obtained at the bottom of the denitrification tower C2.

[0032] The circulating air is pressurized by the circulating compressor NC2, and the pressurized air is then sent to the pressurizing end of the booster expander B-ETA. The air that is pressurized again by the pressurizing end of the booster expander B-ETA enters the main heat exchanger E1, and is divided into two streams after cooling. The first stream is further cooled into liquid air in the main heat exchanger E1, and the second stream is extracted in the middle of the main heat exchanger E1, and then expanded by the expansion end of the booster expander B-ETA. The expanded circulating air serves as the heat source of the deoxygenation reboiler K1. The first stream of liquid air after condensation merges with the liquid air output from the deoxygenation reboiler K1, and is supercooled by the cooler E2, and then sent to the deoxygenation condenser K3 and the denitrification condenser K4 as cold sources.

[0033] A stream of liquid air is drawn from the denitrification condenser K4, and the argon gas evaporated from the top of the liquid argon tank is recovered and liquefied again in the liquefier E3, thereby reducing the evaporation amount of liquid argon, allowing all the evaporated argon products at the top to be recovered, thereby improving the recovery rate of argon.

[0034] The application scope of this process is not limited to air separation crude argon, and it can be applied if the tail gas contains high- and low-boiling point component impurities.

[0035] Embodiment 2: As shown in the attached Figure 2 As shown, based on the first embodiment, the device for rectifying and purifying refined argon further comprises a deoxygenation and dehydration system for removing oxygen and water from nitrogen-containing argon. The deoxygenation and dehydration system is arranged between the crude argon outlet of the deoxygenation tower C1 and the gas inlet of the denitrogenation reboiler K2.

[0036] The deoxygenation and dehydration system includes a catalytic system A for hydrogenation and deoxygenation, a purification system B for catalytic dehydration, a hydrogen-rich booster NC4 and a gas-liquid separator F1. The catalytic system A includes a hydrogenation pipeline, a heater and a catalytic furnace, wherein the heater includes a regenerator and an electric heater arranged in sequence. The nitrogen-containing argon outlet of the deoxygenation tower C1 is merged with the hydrogenation pipeline after passing through the main heat exchanger E1, and then connected to the inlet of the catalytic furnace after passing through the regenerator and the electric heater, and the outlet of the catalytic furnace forms the outlet of the catalytic system A after passing through the regenerator and is connected to the inlet of the purification system B. The purification system B includes a plurality of purification tanks for alternate purification and regeneration, and is equipped with corresponding pipelines and valves. The outlet of the catalytic furnace is connected to the inlet of each purification tank, and the outlet of the purification tank is connected to the inlet of the gas-liquid separator F1 through the main heat exchanger E1. The liquid phase outlet of the gas-liquid separator F1 is connected to the nitrogen-containing argon inlet of the denitrification tower C2, and the gas phase outlet of the gas-liquid separator F1 is connected to the inlet of the hydrogen-rich booster NC4 through the main heat exchanger E1. The outlet of the hydrogen-rich booster NC4 is connected to the hydrogenation pipeline of the catalytic system A.

[0037] The process flow of the deoxygenation and dehydration system is as follows: the nitrogen-containing argon gas with an oxygen content of about 1% obtained from the top of the deoxygenation tower C1 is reheated to room temperature by the main heat exchanger E1 and then enters the catalytic system A. It is hydrogenated and deoxygenated in the catalytic system A and then enters the purification system B. After the water is removed, it enters the main heat exchanger E1 for cooling. After cooling, the gas with some liquid is separated by the gas-liquid separator F1. The separated gas phase containing hydrogen is reheated to room temperature by the main heat exchanger E1 and then compressed by the hydrogen-rich booster NC4 before entering the hydrogenation pipeline, thereby rationally utilizing gas resources, reducing hydrogen consumption, and reducing energy waste. The nitrogen-containing argon liquid in the separated liquid phase is introduced from the upper part of the denitrification tower C2 to continue the second distillation.

[0038] By combining distillation deoxygenation with hydrodeoxygenation, the circulation volume can be reduced and energy consumption can be lowered.

[0039] Embodiment 3: As shown in the attached Figure 3 As shown, the difference between this embodiment and the first embodiment is that the circulating refrigeration part includes a make-up air compressor NC1, a circulating compressor NC2 and a subcooler E2, but does not include a booster turbine expander B-ETA, and the gas outlet of the circulating compressor NC2 is connected to the inlet of the second heat exchange pipeline in the main heat exchanger E1, and the outlet of the second heat exchange pipeline in the main heat exchanger E1 is connected to the gas inlet of the deoxygenation reboiler K1.

[0040] The circulating medium in the circulating refrigeration part is nitrogen. In the deoxygenation reboiler K1, the cooled circulating nitrogen is used as the reboiling heat source, and after condensation, the circulating nitrogen enters the deoxygenation condenser K3 and the denitrogenation condenser K4 respectively as the condensation cold source.

[0041] In addition, in this embodiment, part of the condensation cold source required by the denitrification condenser K4 is provided by the supplementary liquid nitrogen from the liquid nitrogen tank. By adopting the liquid nitrogen refilling method, the circulation volume of the circulator is reduced, the energy consumption is significantly reduced, and the expansion machine is not required to reduce equipment investment.

[0042] The above scheme uses thermal coupling to achieve the purpose of energy saving and consumption reduction, thereby recovering argon in the tail gas to produce high-purity liquid argon, which can save costs for the enterprise and improve economic benefits.

[0043] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for distilling and purifying refined argon, used for distilling raw material crude argon gas to obtain product liquid argon, characterized in that: The method for purifying refined argon by distillation is: S1: The raw material crude argon gas is subjected to a first distillation in a deoxygenation tower to remove at least part of the oxygen to obtain nitrogen-containing argon gas; during the first distillation process, intermediate crude argon gas is extracted from the middle section of the deoxygenation tower, and at least one of the raw material crude argon gas, nitrogen or air provided externally is introduced into a refrigeration cycle as a circulating medium, and the refrigeration cycle is used to provide a reboiling heat source and a condensation cold source for the first distillation, so that the raw material crude argon gas is fully contacted with the rising steam and the reflux in the deoxygenation tower to exchange heat and mass, and the nitrogen-containing argon gas is obtained at the top of the deoxygenation tower; S2: The nitrogen-containing argon gas is subjected to a second distillation in a denitrification tower to remove nitrogen and obtain the product liquid argon; during the second distillation process, the intermediate crude argon gas extracted from the middle section of the deoxygenation tower is used to provide a reboiling heat source for the second distillation, and the intermediate crude argon gas is liquefied into intermediate crude liquid argon after providing heat, and the intermediate crude liquid argon is sent back to the deoxygenation tower as a reflux liquid for the first distillation to participate in the distillation, and at the same time, the refrigeration cycle is used to provide a condensation cold source for the second distillation, so that the nitrogen-containing argon gas is fully in contact with the rising steam and reflux in the denitrification tower to exchange heat and mass, and the product liquid argon is obtained at the bottom of the denitrification tower.

2. The method for purifying refined argon by distillation according to claim 1, characterized in that: The nitrogen-containing argon gas is subjected to hydrogenation catalysis to remove the remaining oxygen, purified to remove water, and then sent to the denitrification tower for a second distillation.

3. A device for distilling and purifying refined argon, used for distilling raw material crude argon gas to obtain product liquid argon, characterized in that: The device for rectifying and purifying refined argon comprises a heat exchange rectification part and a circulating refrigeration part; The heat exchange distillation part includes a deoxygenation tower and a denitrification tower; the deoxygenation tower is used to perform a first distillation on the raw material crude argon gas to remove oxygen to obtain nitrogen-containing argon gas; the denitrification tower is used to perform a second distillation on the nitrogen-containing argon gas to remove nitrogen to obtain the product liquid argon; A deoxygenation condenser is provided at the top of the deoxygenation tower, and a deoxygenation reboiler is provided at the bottom of the deoxygenation tower; The middle part of the deoxidation tower is provided with a crude argon outlet and a crude liquid argon inlet, the crude argon outlet is used to extract the intermediate crude argon generated in the middle section of the first distillation, and the crude liquid argon inlet is used to input the intermediate crude liquid argon; A denitrogenation condenser is provided at the top of the denitrogenation tower, and a denitrogenation reboiler is provided at the bottom of the denitrogenation tower; The denitrification reboiler has a gas inlet and a liquid outlet, the crude argon outlet of the deoxidation tower is connected to the gas inlet of the denitrification reboiler, the intermediate crude argon gas extracted from the middle section of the deoxidation tower is used as a reboiling heat source for the second distillation, the intermediate crude argon gas is liquefied into the intermediate crude liquid argon in the denitrification reboiler, the liquid outlet of the denitrification reboiler is connected to the crude liquid argon inlet of the deoxidation tower, and the intermediate crude liquid argon is input into the deoxidation tower as a reflux liquid for the first distillation; The circulating refrigeration part is used to carry out a refrigeration cycle to provide a reboiling heat source and a condensing cold source for the first distillation and a condensing cold source for the second distillation. The deoxygenation condenser, the deoxygenation reboiler and the denitrogenation condenser are connected to the circulating refrigeration part.

4. The device for rectifying and purifying refined argon according to claim 3, characterized in that: The heat exchange and distillation part also includes a crude argon compressor and a main heat exchanger, which are used to provide a raw gas source of the raw crude argon gas connected to the air inlet of the crude argon compressor, and the air outlet of the crude argon compressor is connected to the inlet of the first heat exchange pipeline in the main heat exchanger, and the outlet of the first heat exchange pipeline in the main heat exchanger is connected to the raw gas inlet of the deoxygenation tower. The nitrogen-containing argon gas outlet of the deoxygenation tower is respectively connected to the nitrogen-containing argon gas inlet of the denitrogenation tower and the gas inlet of the deoxygenation condenser, and the liquid outlet of the deoxygenation condenser is connected to the reflux liquid inlet of the deoxygenation tower. The nitrogen-containing dirty argon gas outlet of the denitrogenation tower is respectively connected to the gas inlet of the denitrogenation condenser and the nitrogen-containing dirty argon gas venting end, and the liquid outlet of the denitrogenation tower is connected to the reflux liquid inlet of the denitrogenation tower.

5. The device for rectifying and purifying refined argon according to claim 4, characterized in that: The circulating refrigeration part includes an air supply compressor, a circulating compressor and a subcooler, wherein the air outlet of the circulating compressor is connected to the inlet of the second heat exchange pipeline in the main heat exchanger, the outlet of the second heat exchange pipeline in the main heat exchanger is connected to the gas inlet of the deoxygenation reboiler, the liquid outlet of the deoxygenation reboiler is connected to the inlet of the first heat exchange pipeline in the subcooler, the outlet of the first heat exchange pipeline in the subcooler is respectively connected to the liquid inlet of the deoxygenation condenser and the liquid inlet of the denitrification condenser, and the gas outlet of the deoxygenation condenser is connected to the inlet of the second heat exchange pipeline in the subcooler The outlet of the second heat exchange pipeline in the subcooler is connected to the inlet of the third heat exchange pipeline in the main heat exchanger, the outlet of the third heat exchange pipeline in the main heat exchanger is connected to the air inlet of the circulation compressor, the gas outlet of the denitrification condenser is connected to the inlet of the third heat exchange pipeline in the subcooler, the outlet of the third heat exchange pipeline in the subcooler is connected to the inlet of the fourth heat exchange pipeline in the main heat exchanger, the outlet of the fourth heat exchange pipeline in the main heat exchanger is connected to the air inlet of the air supply compressor, and the air outlet of the air supply compressor is connected to the air inlet of the circulation compressor.

6. The device for rectifying and purifying refined argon according to claim 5, characterized in that: The circulating refrigeration part also includes a booster turbine expander, the air outlet of the circulating compressor is connected to the inlet of the booster end of the booster turbine expander, the outlet of the booster end of the booster turbine expander is connected to the inlet of the second heat exchange pipeline in the main heat exchanger, the outlet of the second heat exchange pipeline in the main heat exchanger is connected to the inlet of the expansion end of the booster turbine expander, and the outlet of the expansion end of the booster turbine expander is connected to the gas inlet of the deoxygenation reboiler.

7. The device for rectifying and purifying refined argon according to claim 6, characterized in that: The second heat exchange pipeline in the main heat exchanger also branches out a bypass outlet, and the bypass outlet is connected to the inlet of the first heat exchange pipeline in the subcooler.

8. The device for rectifying and purifying refined argon according to claim 5, characterized in that: The circulating refrigeration part also includes a liquefier, the liquid outlet of the denitrification condenser is connected to the inlet of the first heat exchange pipeline in the liquefier, the outlet of the second heat exchange pipeline in the liquefier is connected to the inlet of the third heat exchange pipeline in the subcooler, the evaporated argon gas outlet of the liquid argon tank for storing the product liquid argon is connected to the inlet of the second heat exchange pipeline in the liquefier, and the outlet of the second heat exchange pipeline in the liquefier is connected to the inlet of the liquid argon tank.

9. The device for rectifying and purifying refined argon according to any one of claims 3 to 8, characterized in that: The device for rectifying and purifying refined argon further comprises a deoxygenation and dehydration system disposed between the crude argon outlet of the deoxygenation tower and the gas inlet of the denitrogenation reboiler, wherein the deoxygenation and dehydration system is used to remove oxygen and water from the nitrogen-containing argon gas; The deoxygenation and dehydration system comprises a catalytic system, a purification system, a hydrogen-rich compressor and a gas-liquid separator. The catalytic system comprises a hydrogenation pipeline for hydrogenation and deoxygenation, and the purification system is used for catalytic dehydration. The nitrogen-containing argon gas outlet of the deoxygenation tower is connected to the inlet of the catalytic system via the main heat exchanger, the outlet of the catalytic system is connected to the inlet of the purification system, the outlet of the purification system is connected to the inlet of the gas-liquid separator via the main heat exchanger, the liquid phase outlet of the gas-liquid separator is connected to the nitrogen-containing argon gas inlet of the denitrogenation tower, the gas phase outlet of the gas-liquid separator is connected to the inlet of the hydrogen-rich booster via the main heat exchanger, and the outlet of the hydrogen-rich booster is connected to the hydrogenation pipeline of the catalytic system.

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