An argon recovery system and method based on nano-catalysis and membrane separation synergism

Abstract

The application discloses an argon recovery system and method based on nano-catalysis and membrane separation synergism, and the system comprises an argon pretreatment module, a nano-catalysis reaction module, a membrane separation synergism module and a rectification system. The pretreatment module removes particulates, oil and hydrocarbon impurities through a cyclone separator, an activated carbon adsorption tower and a precision filter. The nano-catalysis module adopts a multi-tube fixed bed reactor, and is internally provided with a carbon nanotube loaded with Pt-CeO2 and a ZSM-5 molecular sieve composite catalyst. CO and O2 are catalytically removed at 180-220 DEG C. The membrane separation module realizes argon-nitrogen separation through a parallel hollow fiber membrane group and a pressure swing adsorption unit. The argon-rich gas is rectified and purified in a low-temperature rectification tower at -180 to -190 DEG C, and the nitrogen-containing gas at the top of the tower is returned to the membrane separation for cyclic treatment. The rectification system integrates a condenser-evaporator, and simultaneously drives the condensation of the gas at the top of the tower and the evaporation of the liquid argon in the tower kettle through liquid nitrogen refrigerant, so that cold-heat coupling is realized. The system is provided with an intelligent control module, and catalytic temperature, membrane separation parameters and reflux ratio are adjusted in real time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas recovery, specifically to an argon recovery system and method based on nano-catalysis and membrane separation synergism. BACKGROUND

[0002] Argon is a rare gas widely used in industrial production, especially in hard alloy manufacturing, precision ceramic sintering, semiconductor production, and metal welding and protective atmosphere. However, due to the low content of argon in air, a large amount of argon consumed in industrial production often needs to be recovered and purified to reduce production costs and improve resource utilization.

[0003] Existing argon recovery technology mainly uses noble metal catalysts combined with distillation processes to remove impurities in waste gas and improve argon purity. However, the existing argon recovery technology has the following problems:

[0004] Incomplete impurity removal: recycled argon often contains CO, O2, N2, and VOCs, etc. impurities, and existing pretreatment technology is difficult to purify completely, affecting the efficiency of subsequent catalytic reactions.

[0005] Catalyst deactivation: traditional noble metal catalysts are prone to carbon deposition, with low CO and O2 removal efficiency, requiring high temperature and high pressure, and high energy consumption.

[0006] Low separation efficiency: argon and nitrogen have similar physical properties, and the membrane separation selectivity is poor, making it difficult to obtain electronic-grade argon, and the nitrogen byproduct is not fully recovered.

[0007] Poor system integration: the existing method is single, waste heat is not recovered, lacks intelligent control, and it is difficult to dynamically optimize operating parameters.

[0008] Therefore, it is urgent to develop an integrated system that is efficient, low in energy consumption, and can synergistically recover argon and nitrogen to improve argon purity and reduce operating costs. SUMMARY

[0009] In view of the deficiencies of the prior art, the present application aims to provide an argon recovery system and method based on nano-catalysis and membrane separation synergism to solve the problems raised in the background art.

[0010] According to an aspect of the present application, an argon recovery system based on nano-catalysis and membrane separation synergism comprises an argon pretreatment module, an inlet of the argon pretreatment module being connected to a recovered argon for removing particulate matter, oil and hydrocarbon impurities in the recovered argon, an outlet of the argon pretreatment module being connected to an inlet of a nano-catalytic reaction module, and a screw compressor being arranged between the nano-catalytic reaction module and the argon pretreatment module, the nano-catalytic reaction module comprising at least two catalytic reactors connected in series, the catalytic reactors being filled with a composite nano-catalyst, the composite nano-catalyst being composed of carbon nanotubes loaded with Pt-CeO2 and molecular sieves, an outlet of the nano-catalytic reaction module being connected to an inlet of a membrane separation synergism module through a heat exchange cooling device, the membrane separation synergism module comprising a pressure swing adsorption unit and a hollow fiber membrane group arranged in parallel, the hollow fiber membrane group being used for separating argon and nitrogen by selective permeation, argon-rich gas separated by the hollow fiber membrane group being output to a rectification system after being pre-cooled by a cold box, the rectification system being capable of purifying the argon-rich gas output by the membrane separation synergism module to electronic-grade high-purity argon, nitrogen-rich gas output by the hollow fiber membrane group being output to the pressure swing adsorption unit, the pressure swing adsorption unit being capable of deeply removing residual argon in the nitrogen-rich gas and outputting the residual argon back to the inlet of the nano-catalytic reaction module for recycling, and purifying the nitrogen-rich gas and outputting it to a nitrogen purification device for further purification, the heat exchange cooling device being capable of recovering waste heat for preheating the system, the system further comprising an intelligent control module connected to the argon pretreatment module, the nano-catalytic reaction module, the screw compressor and the rectification system, and capable of dynamically adjusting the heating power of the catalytic reactor and the membrane separation operation parameters by real-time monitoring of the reaction temperature, pressure and gas composition.

[0011] Preferably, the argon pretreatment module comprises a cyclone separator, an activated carbon adsorption tower and a precision filter, an inlet of the cyclone separator being connected to the recovered argon, an outlet of the cyclone separator being connected to an inlet of the activated carbon adsorption tower, an outlet of the activated carbon adsorption tower being connected to an inlet of the precision filter, and an outlet of the precision filter being connected to an inlet end of the screw compressor, the argon pretreatment module being capable of removing solid particulate matter, oil and hydrocarbon compounds, and dust impurities in the recovered argon through the cyclone separator, the activated carbon adsorption tower and the precision filter.

[0012] Preferably, the nanocatalytic reaction module comprises a multitube fixed bed reactor, a catalyst bed and an electric heating wire, the outlet of the screw compressor is connected to the inlet of the multitube fixed bed reactor, the multitube fixed bed reactor is internally provided with 6 groups of parallel catalytic reaction tubes, each of which is filled with a composite nanocatalyst to form a catalyst bed, and each catalytic reaction tube is provided with an independent electric heating wire on the outer wall, the top of the multitube fixed bed reactor is provided with a gas collector, and the outlet thereof is connected to the inlet of the heat exchange cooling device, and the nanocatalytic reaction module removes carbon monoxide and oxygen in the gas through the catalytic reaction of the multitube fixed bed reactor, the catalyst bed and the electric heating wire.

[0013] Preferably, the preparation method of the composite nanocatalyst comprises:

[0014] After the carbon nanotubes are activated by acid treatment, they are immersed in a mixed solution of chloroplatinic acid and cerium nitrate;

[0015] Pt-CeO2 nanoparticles are loaded at 200℃ by microwave-assisted deposition method;

[0016] The loaded carbon nanotubes and ZSM-5 molecular sieves are mechanically mixed in a mass ratio of 1:3 and formed.

[0017] Preferably, the heat exchange cooling device comprises a plate-fin heat exchanger, a water cooler and a molecular sieve adsorption tower, the hot side inlet of the plate-fin heat exchanger is connected to the outlet of the gas collector, the hot side outlet of the plate-fin heat exchanger is connected to the shell side inlet of the water cooler, the shell side outlet of the water cooler is connected to the inlet of the molecular sieve adsorption tower, the outlet of the molecular sieve adsorption tower is connected to the inlet of the membrane separation enhancement module, the cold side of the plate-fin heat exchanger is formed by the refrigerant of the refrigeration unit, the tube side of the water cooler is cooled by circulating water, the heat recovered by the plate-fin heat exchanger is transported to the heating jacket at the bottom of the activated carbon adsorption tower by a heat medium for activated carbon regeneration, the waste heat recovered by the water cooler is transported to the inlet pipeline of the nanocatalytic reaction module by a heat medium for preheating the recovered argon pretreated by the argon pretreatment module, the plate-fin heat exchanger performs primary cooling on the high-temperature gas discharged from the multitube fixed bed reactor, the water cooler performs secondary cooling, and the molecular sieve adsorption tower is used for removing residual water and carbon dioxide in the gas.

[0018] Preferably, the membrane separation enhancement module comprises a hollow fiber membrane group, a gas buffer tank and a four-tower pressure swing adsorption system, the inlet of the hollow fiber membrane group is connected to the outlet of the molecular sieve adsorption tower, the retentate side of the hollow fiber membrane group is enriched with argon gas which is pre-cooled by a cold box and then delivered to the inlet end of the rectification system, the permeate side of the hollow fiber membrane group is enriched with nitrogen gas and delivered to the gas buffer tank, the outlet of the gas buffer tank is connected to the inlet of the four-tower pressure swing adsorption system, the outlet of the four-tower pressure swing adsorption system is connected to a nitrogen gas purification device, the four-tower pressure swing adsorption system performs fine treatment on the nitrogen-rich gas to form product gas and deliver it to the nitrogen gas purification device for further purification, and the four-tower pressure swing adsorption system generates desorption gas rich in argon which is delivered back to the inlet of the multi-tube fixed bed reactor for recycling treatment; the hollow fiber membrane group adopts a double-layer composite structure, the inner layer is a polyimide selective layer, and the outer layer is a polysulfone support layer, and the membrane pore size is 0.5-2 nm.

[0019] Preferably, the rectification system comprises a low-temperature rectification tower, a condenser-evaporator, an argon liquefier and a reflux pipeline, the low-temperature rectification tower is designed as a vertical stand and is internally filled with high-efficiency structured packing, the outlet of the retentate side of the hollow fiber membrane group is connected to the middle inlet of the low-temperature rectification tower through a compressor and a cold box, the top of the low-temperature rectification tower is integrated with the condenser-evaporator, the gas phase outlet at the top of the low-temperature rectification tower is connected to the shell side inlet of the condenser-evaporator, the liquid phase outlet of the shell side of the condenser-evaporator is connected to the low-temperature rectification tower through a reflux pipeline, the gas phase outlet of the shell side of the condenser-evaporator is connected to the inlet of the membrane separation enhancement module, the tube side of the condenser-evaporator is connected to an external refrigerant group and provides low-temperature cold energy by liquid nitrogen refrigerant, the bottom of the low-temperature rectification tower is integrated with the argon liquefier, the bottom outlet of the low-temperature rectification tower is connected to the inlet of the argon liquefier, the outlet of the argon liquefier is connected to a liquid argon storage tank, and the argon liquefier is a spiral-wound tube heat exchanger using liquid nitrogen as a cold source.

[0020] Preferably, the intelligent control module comprises a laser gas analyzer, thermocouples and a frequency converter of the screw compressor, the detection probes of the laser gas analyzer are respectively installed at the outlet of the argon pre-treatment module, the nano-catalytic reaction module, the permeate outlet of the hollow fiber membrane group and the top outlet of the low-temperature rectification tower, for real-time monitoring of dust residues, oil content, carbon monoxide and oxygen concentration, nitrogen / argon ratio and nitrogen content and feeding back to the control system, each catalytic reaction tube of the multi-tube fixed bed reactor is provided with a thermocouple for independent temperature regulation of each zone, and the frequency converter of the screw compressor is set to dynamically adjust the system pressure.

[0021] Preferably, an argon recovery method based on nano-catalysis and membrane separation enhancement of an argon recovery system, comprising the following steps:

[0022] Step one, the recovered argon gas is transported into a cyclone separator to remove solid large particles in the recovered argon gas by centrifugal force, then transported into an activated carbon adsorption tower to adsorb oil and hydrocarbon compounds, then transported into a precision filter to filter out small particles to obtain pretreated recovered argon gas, the pretreated recovered argon gas is pressurized to 0.8-1.2 MPa by a screw compressor, then enters a multi-tube fixed bed reactor, and reacts to generate carbon dioxide under the catalytic action of composite nano catalyst in the catalyst bed at 180-220℃, to obtain high-temperature crude argon gas;

[0023] Step two, the high-temperature crude argon gas obtained in step one is transported to the hot side of the plate-fin heat exchanger and countercurrently exchanged with the coolant in the cold side, so that the high-temperature crude argon gas is cooled to 80℃, and at the same time the heat recovered by the plate-fin heat exchanger is transported to the heating jacket at the bottom of the activated carbon adsorption tower through the heat conduction oil for activated carbon regeneration, the once-cooled crude argon gas enters the water cooler for secondary cooling to 40℃ and condenses part of the water and carbon dioxide, and at the same time the waste heat recovered by the water cooler is transported to the inlet pipeline of the multi-tube fixed bed reactor through the heat conduction oil for preheating the pretreated recovered argon gas, the secondary-cooled crude argon gas enters the molecular sieve adsorption tower to remove water and carbon dioxide, to obtain clean argon gas;

[0024] Step three, the clean argon gas obtained in step two is transported into a hollow fiber membrane group, and the argon gas is enriched in the retentate side of the hollow fiber membrane group by taking advantage of the difference in permeation rate between argon gas and nitrogen gas, to obtain argon-rich gas with a purity of 99.5%, the permeate of the hollow fiber membrane group is enriched with nitrogen gas and transported to a four-tower pressure swing adsorption system through a gas buffer tank, to obtain nitrogen gas with a purity of 99.99% through fine treatment and transported to a nitrogen gas purification device for further purification and liquefied storage, in addition, the argon-rich desorption gas generated by the four-tower pressure swing adsorption system is transported back to the inlet of the multi-tube fixed bed reactor for recycling;

[0025] Step four, the argon-rich gas with a purity of 99.5% obtained in step three is pressurized to 0.3-0.5 MPa by a compressor and pre-cooled to -150℃ by a cold box, then enters the middle part of a low-temperature rectifying column, the inside of the low-temperature rectifying column is kept at an operating pressure of 0.25 MPa, a column bottom temperature of -185℃ and a column top temperature of -190℃, the argon-rich gas contacts with the downward liquid on the surface of the packing, nitrogen gas is enriched in the top part of the low-temperature rectifying column due to its higher volatility, and high-purity argon gas is enriched in the bottom part of the low-temperature rectifying column, the gas containing nitrogen gas (about 5%-8% nitrogen gas) at the top of the column enters a condenser-evaporator and is partially condensed and liquefied at -195℃, the condensed liquid returns to the low-temperature rectifying column through a reflux pipeline, the uncondensed gas (nitrogen content >90%) returns to the inlet of the membrane separation enhancement module for recycling, and the electronic-grade argon gas (purity ≥99.999%) collected from the bottom of the low-temperature rectifying column is further cooled to below -186℃ by an argon liquefier to form liquid product and stored in a liquid argon storage tank;

[0026] Step five, the intelligent control module monitors the dust residue and oil content at the outlet of the argon pretreatment module, the carbon monoxide and oxygen concentration at the outlet of the multi-tube fixed bed reactor, the nitrogen / argon ratio at the outlet of the hollow fiber membrane group, and the nitrogen content at the top outlet of the low-temperature rectification tower in real time through the laser gas analyzer and the detection probe, and feeds back to the control system, monitors the temperature of the catalyst bed in each catalytic reaction tube through independent thermocouples, so as to independently regulate the temperature of each zone, and dynamically adjusts the system pressure through the setting of the frequency converter of the screw compressor, so that the energy consumption of the system is minimized.

[0027] The above technical scheme is adopted in the present application, and compared with the prior art, has the following technical effects:

[0028] 1. The multi-stage pretreatment module (cyclone separator + activated carbon adsorption tower + precision filter) removes particulate matter, oil and hydrocarbon impurities step by step to ensure the activity of the subsequent catalyst; the composite nano catalyst (Pt-CeO2 / carbon nanotube and ZSM-5 molecular sieve composite) has high specific surface area and anti-carbon deposition performance, and can efficiently catalyze CO and O2 to generate CO2 at a low temperature of 180-220℃, with a reaction efficiency improved by more than 30%; the multi-tube fixed bed reactor (6 groups of parallel catalytic reaction tubes) combines with independent temperature control of each zone to avoid local overheating and deactivate, thereby prolonging the service life of the catalyst.

[0029] 2. The hollow fiber membrane group (polyimide / poly sulfone double-layer composite membrane) realizes preliminary separation by utilizing the difference in the permeation rate of argon and nitrogen, and the argon-rich gas has a purity of 99.5%; the four-tower PSA system in parallel deeply removes argon from the nitrogen-rich gas, and the nitrogen has a purity of 99.99%, and the total recovery rate of argon is increased to more than 98%; the nitrogen-rich gas discharged from the rectification system and the PSA desorption gas are returned to the system inlet for cyclic treatment, thereby maximizing the use of resources and reducing emissions.

[0030] 3. The plate-fin heat exchanger and the water cooler recover the waste heat of the catalytic reaction for regenerating the activated carbon and preheating the raw gas, and the comprehensive energy consumption of the system is reduced by 25%; the low-temperature rectification system adopts a spiral-wound tube type argon liquefier combined with liquid nitrogen refrigerant (-195℃), so that the argon liquefaction efficiency is improved, and the energy consumption is reduced by 15% compared with the traditional process.

[0031] 4. The laser gas analyzer and the thermocouple monitor the gas composition (CO, O2, N2 / Ar ratio) and the reaction temperature in real time, dynamically adjust the heating power of the catalytic reactor, the compressor pressure and the membrane separation parameters, and ensure the stable operation of the system; the frequency conversion speed regulation of the screw compressor automatically adjusts the compression ratio according to the load demand, thereby further reducing the energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a flow diagram of an argon recovery system based on nano-catalysis and membrane separation synergism according to an embodiment of the present application.

[0033] Figure reference numerals: 1. Argon pretreatment module; 11. Cyclone separator; 12. Activated carbon adsorption tower; 13. Precision filter; 2. Nanocatalytic reaction module; 21. Multi-tube fixed bed reactor; 22. Catalyst bed; 23. Gas collector; 3. Screw compressor; 4. Heat exchange and cooling device; 41. Plate-fin heat exchanger; 42. Water cooler; 43. Molecular sieve adsorption tower; 5. Membrane separation enhancement module; 51. Hollow fiber membrane module; 52. Gas buffer tank; 53. Four-tower pressure swing adsorption system; 54. Nitrogen purification device; 6. Distillation system; 61. Low-temperature distillation tower; 62. Condenser evaporator; 63. Argon liquefaction unit; 64. Reflux pipeline; 65. Cold box; 66. Liquid argon storage tank. Detailed Implementation

[0034] To make the content of this application easier to understand, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0035] Example 1

[0036] like Figure 1 As shown, an argon recovery system based on nanocatalysis and membrane separation enhancement includes an argon pretreatment module 1, a nanocatalytic reaction module 2, a screw compressor 3, a membrane separation enhancement module 5, a distillation system 6, a heat exchange and cooling device 4, and an intelligent control module. The argon pretreatment module 1 includes a cyclone separator 11, an activated carbon adsorption tower 12, and a precision filter 13. The nanocatalytic reaction module 2 includes a multi-tube fixed-bed reactor 21, a catalyst bed 22, and an electric heating wire. The heat exchange and cooling device 4 includes a plate-fin heat exchanger 41, a water cooler 42, and a molecular sieve adsorption tower 43. The membrane separation enhancement module 5 includes a hollow fiber membrane module 51, a gas buffer tank 52, and a four-tower pressure swing adsorption system 53. The distillation system 6 includes a cryogenic distillation tower 61, a condenser-evaporator 62, an argon liquefaction unit 63, and a reflux pipeline 64.

[0037] Specifically, the inlet of the cyclone separator 11 is fed with recovered argon gas. The cyclone separator 11 uses centrifugal force to remove solid particles (such as metal scraps and silicon powder) with a particle size >10μm from the recovered argon gas. The outlet of the cyclone separator 11 is connected to the inlet of the activated carbon adsorption tower 12. The activated carbon adsorption tower 12 is used to adsorb oil mist (lubricating oil, hydraulic oil) and hydrocarbon compounds (CH4, C2H6) from the recovered argon gas. The outlet of the activated carbon adsorption tower 12 is connected to the inlet of the precision filter 13, which is used to filter out 0.1μm particles from the recovered argon gas to ensure that dust residue is <0.1mg / m³. 3 The outlet of the precision filter 13 is connected to the inlet of the screw compressor 3, which raises the gas pressure from atmospheric pressure to 1.2 MPa to meet the requirements of subsequent catalytic reactions.

[0038] The outlet of the screw compressor 3 is connected to the inlet of the multi-tube fixed-bed reactor 21. The multi-tube fixed-bed reactor 21 contains six sets of parallel catalytic reaction tubes, each filled with a composite nanocatalyst to form a catalyst bed 22. The composite nanocatalyst is composed of carbon nanotubes loaded with Pt-CeO2 and molecular sieves. The preparation method of the composite nanocatalyst includes: activating the carbon nanotubes with acid treatment, then impregnating them in a mixed solution of chloroplatinic acid and cerium nitrate; loading Pt-CeO2 nanoparticles at 200℃ using microwave-assisted deposition; and mechanically mixing the loaded carbon nanotubes with ZSM-5 molecular sieves at a mass ratio of 1:3 to form a composite catalyst with a specific surface area of ​​680 m². 2 / g, with high specific surface area and anti-carbon deposition performance, can efficiently catalyze the conversion of CO and O2 to CO2 at low temperatures of 180-220℃, improving the reaction efficiency by more than 30%; and each catalytic reaction tube is equipped with an independent electric heating wire on its outer wall, and each catalytic reaction tube is equipped with a thermocouple. The temperature of the catalyst bed 22 in each catalytic reaction tube is monitored by independent thermocouples, so as to facilitate independent temperature control of each zone, avoid local overheating and deactivation, and extend the catalyst life; the top of the multi-tube fixed bed reactor 21 is equipped with a gas collector 23, and its outlet is connected to the inlet of the hot side of the plate-fin heat exchanger 41.

[0039] The hot-side outlet of the plate-fin heat exchanger 41 is connected to the shell-side inlet of the water cooler 42, the shell-side outlet of the water cooler 42 is connected to the inlet of the molecular sieve adsorption tower 43, and the outlet of the molecular sieve adsorption tower 43 is connected to the inlet of the membrane separation enhancement module 5. The cold side of the plate-fin heat exchanger 41 is formed by the refrigerant of the refrigeration unit, and the tube side of the water cooler 42 is cooled by circulating water. The plate-fin heat exchanger 41 uses the high-temperature gas (250°C) at the reactor outlet to exchange heat countercurrently with the refrigerant, precooling the gas to 80°C. At the same time, the recovered heat is transported to the bottom heating jacket of the activated carbon adsorption tower 12 through the heat medium (heat transfer oil) for activated carbon regeneration. The water cooler 42 cools the gas a second time to 40°C, condensing some moisture and CO2. At the same time, the recovered waste heat is transported to the inlet pipeline of the multi-tube fixed bed reactor 21 through the heat medium for preheating the recovered argon gas after pretreatment in the argon pretreatment module 1, thereby saving energy. The molecular sieve adsorption tower 43 is used to remove residual moisture and carbon dioxide from the cooled gas.

[0040] The inlet of the hollow fiber membrane group 51 is connected to the outlet of the molecular sieve adsorption tower 43, the hollow fiber membrane group 51 adopts a double-layer composite structure, the inner layer is a polyimide selective layer, and the outer layer is a polysulfone support layer, the membrane pore size is 0.5-2 nm, the hollow fiber membrane group 51 utilizes the difference in Ar and N2 permeation rate (Ar permeation coefficient 0.5 Barrer, N2 4.2 Barrer), Ar is enriched in the retentate side (non-permeation side), the retentate side of the hollow fiber membrane group 51 is enriched with argon, which is pressurized to 0.3-0.5 MPa by a compressor and pre-cooled to -150°C by a cold box 65 before entering the middle of the low-temperature rectification tower 61, the permeation side of the hollow fiber membrane group 51 is enriched with nitrogen and transported into the gas buffer tank 52, the gas buffer tank 52 balances the flow fluctuation between the membrane separation and the PSA, the volume is designed to be 20% of the system processing capacity, the outlet of the gas buffer tank 52 is connected to the inlet of the four-tower pressure swing adsorption system 53 (PSA), the PSA system can deeply remove the Ar residues in the permeation side gas (the purity is increased to more than 99.9%), the outlet of the four-tower pressure swing adsorption system 53 (PSA) is connected to the nitrogen purification device 54, the four-tower pressure swing adsorption system 53 performs fine treatment on the nitrogen-rich gas to form PSA product gas and transport it to the nitrogen purification device 54 for further purification, and the PSA desorption gas (containing Ar 5-8%) rich in argon generated by the four-tower pressure swing adsorption system 53 is transported back to the inlet of the multi-tube fixed bed reactor 21 for recycling.

[0041] The low-temperature rectification tower 61 is vertically designed and filled with high-efficiency structured packing inside, under the operating conditions of -180 to -190 ℃ and 0.2 to 0.5 MPa, multi-stage gas-liquid mass transfer separation is performed by using the boiling point difference of argon (boiling point -185.9 ℃) and nitrogen (boiling point -195.8 ℃), a liquid distributor is arranged at the feeding position in the middle of the tower to ensure uniform distribution of argon-rich gas; nitrogen-containing residual gas is collected at the top of the tower, and electronic-grade argon with a purity of ≥99.999% is obtained at the bottom of the tower; the outlet of the retentate side of the hollow fiber membrane group 51 is connected to the middle inlet of the low-temperature rectification tower 61 through a compressor and a cold box 65, the top of the low-temperature rectification tower 61 is integrated and connected to a condenser-evaporator 62, and the gas phase outlet at the top of the low-temperature rectification tower 61 is connected to the inlet of the shell side of the condenser-evaporator 62, the liquid phase outlet of the shell side of the condenser-evaporator 62 is connected to the low-temperature rectification tower 61 through a reflux pipeline 64, the gas phase outlet of the shell side of the condenser-evaporator 62 is connected to the inlet of the membrane separation enhancement module 5, and the tube side of the condenser-evaporator 62 is connected to an external refrigerant group and provides low-temperature cold energy by liquid nitrogen refrigerant; the nitrogen-containing mixed gas (containing a small amount of argon) discharged from the top of the low-temperature rectification tower 61 enters the shell side of the condenser-evaporator 62 and exchanges heat with the liquid nitrogen refrigerant (-196 ℃) in the tube side, argon (boiling point -185.9 ℃) is condensed into liquid first due to its higher boiling point than nitrogen (boiling point -195.8 ℃), forming reflux liquid which returns to the top of the tower through the reflux pipeline 64, maintaining the liquid phase reflux of the rectification tower (controlling the reflux ratio to be 1:3 to 1:5), and the uncondensed nitrogen-rich gas (nitrogen content >90%) returns to the membrane separation enhancement module 5 for recycling treatment; after absorbing the heat of the tower top gas of the shell side, the liquid nitrogen refrigerant in the tube side of the condenser-evaporator 62 partially vaporizes, and the latent heat (about 199 kJ / kg) released during the vaporization of the liquid nitrogen refrigerant is transferred to the liquid argon (high-purity argon is liquefied and accumulated in the tower kettle) at the bottom of the low-temperature rectification tower 61 through the heat transfer wall, providing a reboiling heat source to evaporate part of the liquid argon into gas phase, forming an ascending vapor (maintaining the gas-liquid mass transfer power in the tower); the bottom of the low-temperature rectification tower 61 is integrated and connected to an argon liquefier 63, the outlet of the low-temperature rectification tower 61 is connected to the inlet of the argon liquefier 63, the outlet of the argon liquefier 63 is connected to a liquid argon storage tank 66, and the argon liquefier 63 is a spiral-wound tube heat exchanger which uses liquid nitrogen as a cold source to further cool the high-purity argon at the bottom to a liquid state, realizing the final productization of electronic-grade liquid argon; in addition, a pneumatic regulating valve and a flowmeter are arranged on the reflux pipeline 64, the reflux ratio is dynamically adjusted according to the feedback of the tower top temperature sensor (control range 1:3 to 1:5), and the separation efficiency and energy consumption are optimized.

[0042] The intelligent control module is connected with the argon pretreatment module 1, the nanometer catalytic reaction module 2, the screw compressor and the rectification system 6 respectively, through real-time monitoring of the reaction temperature, pressure and gas composition, the catalytic reactor heating power and the membrane separation operation parameters are dynamically adjusted, specifically, the intelligent control module includes a laser gas analyzer, a thermocouple and a frequency converter of the screw compressor 3, the detection probe of the laser gas analyzer is installed at the outlet of the argon pretreatment module 1, the multi-tube fixed bed reactor 21, the permeation measuring outlet of the hollow fiber membrane group 51 and the top outlet of the low-temperature rectification tower 61 respectively, which is used for real-time monitoring of dust residue, oil content, carbon monoxide and oxygen concentration, nitrogen / argon ratio and nitrogen content and feeding back to the control system, the thermocouple is arranged on each catalytic reaction tube of the multi-tube fixed bed reactor 21 for independent temperature regulation, and the frequency converter of the screw compressor 3 is arranged to dynamically adjust the system pressure.

[0043] Embodiment 2

[0044] An argon recovery method of an argon recovery system based on nanometer catalysis and membrane separation synergism, comprising the following steps:

[0045] Step one, the recovered argon is transported into the cyclone separator 11 to remove solid particles (such as metal scraps and silicon powder) with a particle size of >10 μm by centrifugal force, then transported into the activated carbon adsorption tower 12 to adsorb oil (lubricating oil and hydraulic oil) and hydrocarbon compounds (CH4 and C2H6), then transported into the precision filter 13 to filter out 0.1 μm particles, to ensure that the dust residue is <0.1 mg / m 3 , to obtain pretreated recovered argon, after the pretreated recovered argon is pressurized to 1.2 MPa by the screw compressor 3, it enters the multi-tube fixed bed reactor 21, and under the catalytic action of the composite nanometer catalyst in the catalyst bed 22 inside the reactor, carbon monoxide and oxygen react to generate carbon dioxide, to obtain high-temperature crude argon;

[0046] Step two, the high-temperature crude argon obtained in step one is transported to the hot side of the plate-fin heat exchanger 41 and countercurrently exchanged with the coolant in the cold side, so that the high-temperature crude argon is cooled to 80℃, and at the same time, the heat recovered by the plate-fin heat exchanger 41 is transported to the activated carbon regeneration heating jacket at the bottom of the activated carbon adsorption tower 12 through the heat conduction oil, the once-cooled crude argon enters the water cooler 42 for secondary cooling to 40℃ and condenses part of the water and carbon dioxide, at the same time, the waste heat recovered by the water cooler 42 is transported to the inlet pipeline of the multi-tube fixed bed reactor 21 through the heat conduction oil for preheating the pretreated recovered argon, and the secondary-cooled crude argon enters the molecular sieve adsorption tower 43 to remove water and carbon dioxide, to obtain clean argon;

[0047] Step three, the clean argon obtained in step two is transported into the hollow fiber membrane group 51, using the difference in permeation rate of argon and nitrogen, argon is enriched in the retentate side of the hollow fiber membrane group 51, obtaining argon-rich gas with a purity of 99.5%, the permeate enriched nitrogen in the hollow fiber membrane group 51 is transported into the four-tower pressure swing adsorption system 53 through the gas buffer tank 52, and the nitrogen gas with a purity of 99.99% obtained by fine treatment is transported into the nitrogen purification device 54 for further purification and liquefied storage. In addition, the argon-rich desorption gas generated by the four-tower pressure swing adsorption system 53 is transported back to the inlet of the multi-tube fixed bed reactor 21 for recycling treatment.

[0048] Step four, the argon-rich gas with a purity of 99.5% obtained in step three is pressurized to 0.3-0.5MPa by a compressor and pre-cooled to -150℃ by a cold box 65, then enters the middle of the low-temperature rectification tower 61. The inside of the low-temperature rectification tower 61 maintains an operating pressure of 0.25MPa and a tower bottom temperature of -185℃ and a tower top temperature of -190℃. The argon-rich gas contacts with the downward liquid on the surface of the packing. Nitrogen gas is enriched at the top of the low-temperature rectification tower 61 due to its higher volatility. High-purity argon gas is enriched at the bottom of the low-temperature rectification tower 61. The gas containing nitrogen gas (about 5%-8% nitrogen gas) at the top of the tower enters the condenser evaporator 62 and is partially condensed and liquefied at -195℃. The condensed liquid returns to the low-temperature rectification tower 61 through the reflux pipeline 64. The uncondensed gas (nitrogen content >90%) returns to the inlet of the membrane separation enhancement module 5 for recycling treatment. The electronic-grade argon gas (purity ≥99.999%) taken from the bottom of the low-temperature rectification tower 61 is further cooled to below -186℃ by the argon liquefier 63 to form a liquid product stored in the liquid argon storage tank 66.

[0049] Step five, the intelligent control module monitors the dust residue and oil content at the outlet of the argon pretreatment module 1, the carbon monoxide and oxygen concentration at the outlet of the multi-tube fixed bed reactor 21, the nitrogen / argon ratio at the outlet of the hollow fiber membrane group 51, and the nitrogen content at the top outlet of the low-temperature rectification tower 61 in real time through the laser gas analyzer and detection probe, and feeds back to the control system. The temperature of the catalyst bed 22 in each catalytic reaction tube is monitored by independent thermocouples to independently regulate the temperature of each zone. The system pressure can be dynamically adjusted by setting the frequency converter of the screw compressor 3 to minimize energy consumption.

[0050] The above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, and not to limit them. Although the embodiments of the present application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified or some technical features can be replaced by equivalents without departing from the spirit and scope defined by the claims of the present application.

Claims

1. An argon recovery system based on the synergistic effect of nanocatalysis and membrane separation, characterized in that, The system comprises an argon pretreatment module (1), an inlet of the argon pretreatment module (1) is connected with recycled argon, the argon pretreatment module (1) is used for removing particulate matter, oil and hydrocarbon impurities in the recycled argon, an outlet of the argon pretreatment module (1) is connected with an inlet of a nano-catalytic reaction module (2), a screw compressor (3) is arranged between the nano-catalytic reaction module (2) and the argon pretreatment module (1), the nano-catalytic reaction module (2) comprises at least two catalytic reactors connected in series, the catalytic reactors are filled with a composite nano-catalyst, the composite nano-catalyst is composed of carbon nanotubes loaded with Pt-CeO2 and molecular sieves, an outlet of the nano-catalytic reaction module (2) is connected with an inlet of a membrane separation and enhancement module (5) through a heat exchange and cooling device (4), the membrane separation and enhancement module (5) comprises a pressure swing adsorption unit and a hollow fiber membrane group (51) arranged in parallel, the hollow fiber membrane group (51) is used for separating argon and nitrogen by selective permeation, argon-rich gas separated by the hollow fiber membrane group (51) is pre-cooled by a cold box (65) and then output to a rectification system (6), the rectification system (6) can purify the argon-rich gas output by the membrane separation and enhancement module (5) to electronic-grade high-purity argon, nitrogen-rich gas discharged from the rectification system (6) is returned to the inlet of the membrane separation and enhancement module (5) for recycling, nitrogen-rich gas separated by the hollow fiber membrane group (51) is output to the pressure swing adsorption unit, the pressure swing adsorption unit can deeply remove residual argon in the nitrogen-rich gas and output the residual argon to the inlet of the nano-catalytic reaction module (2) for recycling, purify the nitrogen-rich gas and output the nitrogen-rich gas to a nitrogen purification device (54) for further purification, the heat exchange and cooling device (4) can recover waste heat for preheating the system, the system further comprises an intelligent control module, the intelligent control module is connected with the argon pretreatment module (1), the nano-catalytic reaction module (2), the screw compressor (3) and the rectification system (6) respectively, and the intelligent control module can dynamically adjust the heating power of the catalytic reactor and the membrane separation operation parameters by real-time monitoring of the reaction temperature, pressure and gas composition.

2. The argon recovery system based on the synergism of nanocatalysis and membrane separation according to claim 1, characterized in that, The argon pretreatment module (1) comprises a cyclone separator (11), an activated carbon adsorption tower (12) and a precision filter (13), an inlet of the cyclone separator (11) is connected with recycled argon, an outlet of the cyclone separator (11) is connected with an inlet of the activated carbon adsorption tower (12), an outlet of the activated carbon adsorption tower (12) is connected with an inlet of the precision filter (13), and an outlet of the precision filter (13) is connected with an inlet end of the screw compressor (3), the argon pretreatment module (1) can remove solid particulate matter, oil, hydrocarbon compounds and dust impurities in the recycled argon through the cyclone separator (11), the activated carbon adsorption tower (12) and the precision filter (13).

3. The argon recovery system based on the synergistic effect of nanocatalysis and membrane separation according to claim 2, characterized in that, The nano-catalytic reaction module (2) comprises a multi-tube fixed bed reactor (21), a catalyst bed (22) and an electric heating wire, the inlet of the multi-tube fixed bed reactor (21) is connected to the outlet end of the screw compressor (3), the inside of the multi-tube fixed bed reactor (21) is provided with 6 groups of parallel catalytic reaction tubes, each of the catalytic reaction tubes is filled with a composite nano-catalyst to form a catalyst bed (22), and the outer wall of each of the catalytic reaction tubes is provided with an independent electric heating wire, the top of the multi-tube fixed bed reactor (21) is provided with a gas collector (23) and the outlet thereof is connected to the inlet of the heat exchange cooling device (4), the nano-catalytic reaction module (2) removes carbon monoxide and oxygen in the gas by catalytic reaction of the multi-tube fixed bed reactor (21), the catalyst bed (22) and the electric heating wire.

4. The argon recovery system based on the synergism of nanocatalysis and membrane separation according to claim 3, characterized in that, The preparation method of the composite nano-catalyst comprises: After the carbon nanotube is activated by acid treatment, it is immersed in a mixed solution of chloroplatinic acid and cerium nitrate; Pt-CeO2 nanoparticles are loaded at 200 DEG C by a microwave-assisted deposition method; The loaded carbon nanotube is mechanically mixed with ZSM-5 molecular sieve at a mass ratio of 1:3 to form a shape.

5. The argon recovery system based on the synergistic effect of nanocatalysis and membrane separation according to claim 4, characterized in that, The heat exchange cooling device (4) comprises a plate-fin heat exchanger (41), a water cooler (42) and a molecular sieve adsorption tower (43), the hot side inlet of the plate-fin heat exchanger (41) is connected to the outlet of the gas collector (23), the hot side outlet of the plate-fin heat exchanger (41) is connected to the shell side inlet of the water cooler (42), the shell side outlet of the water cooler (42) is connected to the inlet of the molecular sieve adsorption tower (43), the outlet of the molecular sieve adsorption tower (43) is connected to the inlet of the membrane separation enhancement module (5), the cold side of the plate-fin heat exchanger (41) is formed by the refrigerant of a refrigerating unit, the tube side of the water cooler (42) is cooled by circulating water, the heat recovered by the plate-fin heat exchanger (41) is delivered to the heating jacket at the bottom of the activated carbon adsorption tower (12) through a heat medium to be used for activated carbon regeneration, the waste heat recovered by the water cooler (42) is delivered to the inlet pipeline of the nano-catalytic reaction module (2) through a heat medium to be used for preheating the recovered argon after pretreatment of the argon pretreatment module (1), the plate-fin heat exchanger (41) performs primary cooling on the high-temperature gas from the multi-tube fixed bed reactor (21), the water cooler (42) performs secondary cooling, and the molecular sieve adsorption tower (43) is used for removing residual water and carbon dioxide in the gas.

6. The argon recovery system based on the synergistic effect of nanocatalysis and membrane separation according to claim 5, characterized in that, The membrane separation synergistic module (5) comprises a hollow fiber membrane group (51), a gas buffer tank (52) and a four-tower pressure swing adsorption system (53), the inlet of the hollow fiber membrane group (51) is connected to the outlet of the molecular sieve adsorption tower (43), the retentate side of the hollow fiber membrane group (51) is enriched with argon and is delivered to the inlet end of the rectification system (6) after being pre-cooled by a cold box (65), the permeate side of the hollow fiber membrane group (51) is enriched with nitrogen and is delivered to the gas buffer tank (52), the outlet of the gas buffer tank (52) is connected to the inlet of the four-tower pressure swing adsorption system (53), the outlet of the four-tower pressure swing adsorption system (53) is connected to the nitrogen purification device (54), the four-tower pressure swing adsorption system (53) performs fine treatment on the nitrogen-rich gas to form product gas and deliver the product gas to the nitrogen purification device (54) for further purification, and the desorption gas rich in argon generated by the four-tower pressure swing adsorption system (53) is delivered back to the inlet of the multi-tube fixed bed reactor (21) for recycling treatment. The hollow fiber membrane group (51) adopts a double-layer composite structure, the inner layer is a polyimide selective layer, and the outer layer is a polysulfone support layer, and the membrane pore size is 0.5-2 nm.

7. The argon recovery system based on the synergistic effect of nanocatalysis and membrane separation according to claim 6, characterized in that, The rectification system (6) comprises a low-temperature rectification tower (61), a condenser-evaporator (62), an argon liquefier (63) and a reflux pipeline (64), the low-temperature rectification tower (61) is designed as a vertical stand and is internally filled with high-efficiency structured packing, the outlet of the retentate side of the hollow fiber membrane group (51) is connected to the middle inlet of the low-temperature rectification tower (61) through a compressor and a cold box (65), the top of the low-temperature rectification tower (61) is integrally connected to the condenser-evaporator (62), the top gas phase outlet of the low-temperature rectification tower (61) is connected to the shell side inlet of the condenser-evaporator (62), the liquid phase outlet of the shell side of the condenser-evaporator (62) is connected to the low-temperature rectification tower (61) through the reflux pipeline (64), the gas phase outlet of the shell side of the condenser-evaporator (62) is connected to the inlet of the membrane separation synergistic module (5), the tube side of the condenser-evaporator (62) is connected to an external refrigerant group and provides low-temperature cold energy by means of liquid nitrogen refrigerant, the bottom of the low-temperature rectification tower (61) is integrally connected to the argon liquefier (63), the bottom outlet of the low-temperature rectification tower (61) is connected to the inlet of the argon liquefier (63), the outlet of the argon liquefier (63) is connected to a liquid argon storage tank (66), and the argon liquefier (63) is a spiral-wound tube heat exchanger and uses liquid nitrogen as a cold source.

8. The argon recovery system based on the synergistic effect of nanocatalysis and membrane separation according to claim 7, characterized in that, The intelligent control module includes a laser gas analyzer, thermocouples and a frequency converter of the screw compressor (3), the detection probe of the laser gas analyzer is respectively installed at the outlet of the argon pretreatment module (1), the nanometer catalytic reaction module (2), the permeation measurement outlet of the hollow fiber membrane group (51) and the top outlet of the low-temperature rectifying tower (61), which is used for real-time monitoring of dust residues, oil content, carbon monoxide and oxygen concentration, nitrogen / argon ratio and nitrogen content and feeding back to the control system, the thermocouples are arranged on each catalytic reaction tube of the multi-tube fixed bed reactor (21) for independent regulation of the temperature of each zone, and the frequency converter of the screw compressor (3) can dynamically adjust the system pressure.

9. An argon recovery method based on the argon recovery system according to any one of claims 1 to 8, characterized by, The method comprises the following steps: Step one, the recovered argon is transported into a cyclone separator (11) to remove solid large particles in the recovered argon by centrifugal force, then transported into an activated carbon adsorption tower (12) to adsorb oil and hydrocarbon compounds, then transported into a precision filter (13) to filter out small particles to obtain pretreated recovered argon, the pretreated recovered argon is pressurized to 0.8-1.2 MPa by a screw compressor (3) and then enters a multi-tube fixed bed reactor (21), where carbon monoxide and oxygen react to generate carbon dioxide under the catalytic action of the composite nanometer catalyst in the catalyst bed (22) inside the reactor at 180-220℃, to obtain high-temperature crude argon; Step two, the high-temperature crude argon obtained in step one is transported to the hot side of a plate-fin heat exchanger (41) and countercurrently exchanged with the coolant in the cold side, so that the high-temperature crude argon is cooled to 80℃, and at the same time, the heat recovered by the plate-fin heat exchanger (41) is transported to the heating jacket at the bottom of the activated carbon adsorption tower (12) through heat-conducting oil for activated carbon regeneration, the once-cooled crude argon enters a water cooler (42) for secondary cooling to 40℃ and condenses part of the water and carbon dioxide, at the same time, the waste heat recovered by the water cooler (42) is transported to the inlet pipeline of the multi-tube fixed bed reactor (21) through heat-conducting oil for preheating the pretreated recovered argon, the twice-cooled crude argon enters a molecular sieve adsorption tower (43) to remove water and carbon dioxide, to obtain clean argon; Step three, the clean argon obtained in step two is transported into a hollow fiber membrane group (51), and the argon is enriched on the permeation residue side of the hollow fiber membrane group (51) by using the difference in permeation rate between argon and nitrogen, to obtain argon-rich gas with a purity of 99.5%, the permeation measurement nitrogen is enriched in the hollow fiber membrane group (51) and transported to a four-tower pressure swing adsorption system (53) through a gas buffer tank (52), to obtain nitrogen with a purity of 99.99% through fine treatment and transported to a nitrogen purification device (54) for further purification and liquefied storage, in addition, the argon-rich desorption gas produced by the four-tower pressure swing adsorption system (53) is transported back to the inlet of the multi-tube fixed bed reactor (21) for recycling treatment; Step four, the argon-rich gas with 99.5% purity obtained in step three is pressurized to 0.3-0.5 MPa by a compressor and pre-cooled to -150°C by a cold box (65) before entering the middle of a low-temperature rectification column (61), which is kept at an operating pressure of 0.25 MPa, a column bottom temperature of -185°C and a column top temperature of -190°C. The argon-rich gas contacts with the liquid flowing downward on the surface of the packing. Nitrogen gas is enriched at the top of the low-temperature rectification column (61) due to its higher volatility, and high-purity argon gas is enriched at the bottom of the low-temperature rectification column (61). The gas containing 5%-8% nitrogen at the top of the low-temperature rectification column (61) enters a condenser-evaporator (62) and is partially condensed and liquefied at -195°C. The condensed liquid returns to the low-temperature rectification column (61) through a reflux line (64). The uncondensed gas with a nitrogen content of >90% returns to the inlet of the membrane separation enhancement module (5) for recycling. The electronic-grade argon gas with a purity of ≥99.999% collected from the bottom of the low-temperature rectification column (61) is further cooled to below -186°C by an argon liquefier (63) to form a liquid product, which is stored in a liquid argon storage tank (66); Step five, the intelligent control module monitors the dust and oil residues at the outlet of the argon pretreatment module (1), the carbon monoxide and oxygen concentrations at the outlet of the multi-tube fixed-bed reactor (21), the nitrogen / argon ratio at the outlet of the hollow fiber membrane group (51), and the nitrogen content at the top outlet of the low-temperature rectification column (61) in real time through laser gas analyzers and detection probes, and feeds back to the control system. The temperature of the catalyst bed (22) in each catalytic reaction tube is monitored by independent thermocouples to independently regulate the temperature of each zone. The system pressure is dynamically adjusted by the frequency converter of the screw compressor (3) to minimize energy consumption.

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