Device and method for removing olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons

Abstract

The present invention relates to a device and method for removing olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons, belonging to the technical field of gas purification. The oxidation tower, adsorption tower and purification tower in the removal device are connected in sequence, the sodium persulfate storage tank is connected to the upper part of the oxidation tower, and the halogenated hydrocarbon storage tank is connected to the lower part of the oxidation tower; the removal method utilizes the sodium persulfate aqueous solution to react with the baffle plate made of transition metal material inside the oxidation tower to generate strong oxidizing free radicals, oxidizes the olefin, alkyne and cyclic hydrocarbon impurities that are difficult to separate in the halogenated hydrocarbons to form organic or inorganic small molecule impurities that are easy to remove, and then removes them by adsorption and distillation, thereby obtaining halogenated hydrocarbons with a purity of more than 99.999 vol%. The removal device of the present invention has a simple structure, low investment, low operating energy consumption, and the removal method has strong operability and is easy to realize industrial production, thereby solving the problem that olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons are difficult to remove.

Description

Technical Field

[0001] The invention relates to a device and a method for removing olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons, belonging to the technical field of gas purification. Background Art

[0002] The development trend of electronic specialty gases is high purification and trace impurity content, and conventional, single separation technology is difficult to achieve the separation requirements.

[0003] At present, various methods for removing organic impurities of halogenated hydrocarbons have been disclosed in existing documents or patents. In the US5523499A patent applied by DuPont in 1994, it was proposed to use activated carbon or inorganic molecular sieves as adsorbents to adsorb impurities in crude hexafluoroethane. In the CN103664502A patent applied by Foshan Huate Gas Co., Ltd. and Guangdong South China Special Gas Research Institute Co., Ltd. in 2012, it was proposed to purify octafluoropropane through the steps of normal temperature adsorption + distillation + low temperature adsorption + pressurized adsorption. The CN105777483A patent jointly applied by Guangdong Huate Gas Co., Ltd. and Jiangxi Huate Electronic Chemicals Co., Ltd. in 2016 proposed that the raw material intake gas be subjected to initial adsorption, followed by light distillation and heavy distillation, and then subjected to two deep adsorptions to achieve high-purity octafluorocyclobutane. The patent JP10182516A applied by Daikin in 1996 proposed to form octafluorodichlorobutane with a high boiling point by chlorinating octafluorobutene in a mixture of octafluorocyclobutane and octafluorobutene, and then separating octafluorocyclobutane from the mixture by distillation. The above method can remove organic impurities to a certain extent, but the process is complicated and the efficiency is low. In addition, because the organic matter has a complex structure, a wide variety, and great differences in properties, the intermolecular forces of olefin, alkyne or cycloalkane impurities are large or they are easy to azeotropy with the target product. It is difficult to completely and efficiently remove impurities only through adsorption and purification processes, and the product purity is difficult to reach 99.999% or above. Summary of the invention

[0004] In view of this, the present invention provides a device and method for removing olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons. The removal device includes an oxidation tower, an adsorption tower and a purification tower. First, olefins, alkynes and cyclic hydrocarbon impurities that are difficult to separate in halogenated hydrocarbons are removed by oxidation-reduction reaction, and then small molecular organic matter and inorganic impurities such as hydrogen, oxygen, nitrogen and water in the halogenated hydrocarbons are removed by adsorption and distillation. Finally, halogenated hydrocarbons with a purity of more than 99.999 vol% can be obtained, and it is easy to realize industrial production.

[0005] The objectives of the present invention are achieved through the following technical solutions.

[0006] A device for removing olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons, the device comprising a sodium persulfate storage tank, a halogenated hydrocarbon storage tank, an oxidation tower, an adsorption tower and a purification tower;

[0007] The oxidation tower is provided with baffles inside, and the baffles are transition metal plates. The sodium persulfate aqueous solution is baffled layer by layer through the baffles, which can, on the one hand, make the sodium persulfate aqueous solution react with the transition metal in the baffles to generate strong oxidizing free radicals, and on the other hand, can fully contact with the halogenated hydrocarbons to generate redox reactions, so that the olefins, alkynes and cyclic hydrocarbon impurities that are difficult to remove are converted into organic or inorganic small molecule impurities that are easy to remove; the upper part of the oxidation tower is provided with a liquid inlet and a gas outlet, and the lower part is provided with a gas inlet and a liquid discharge port;

[0008] The adsorption tower removes some impurities in the halogenated hydrocarbons by physical adsorption; the adsorption tower is filled with adsorbents, such as commonly used activated carbon, aluminum oxide and solid alkali; the lower part of the adsorption tower is provided with an air inlet, and the upper part is provided with an air outlet;

[0009] The purification tower removes some impurities in the halogenated hydrocarbons by distillation; the purification tower is filled with packing, such as commonly used θ rings, ball rings, Raschig rings and structured packing, etc.; the lower part of the purification tower is provided with an air inlet, and the upper part is provided with an air outlet;

[0010] The sodium persulfate storage tank is connected to the liquid inlet of the oxidation tower, the halogenated hydrocarbon storage tank is connected to the air inlet of the oxidation tower, the liquid discharge port of the oxidation tower is connected to a liquid discharge pipe, the air outlet of the oxidation tower is connected to the air inlet of the adsorption tower, the air outlet of the adsorption tower is connected to the air inlet of the purification tower, and the air outlet of the purification tower is connected to a halogenated hydrocarbon discharge pipe.

[0011] Furthermore, a gas distributor is provided at the bottom of the oxidation tower. The gas distributor is located below the baffle plate. The halogenated hydrocarbons entering the oxidation tower from the bottom of the oxidation tower can be evenly distributed through the gas distributor.

[0012] Furthermore, the baffle is a fourth period transition metal plate, more preferably an iron plate, a manganese plate, a copper plate or a nickel plate.

[0013] Furthermore, grooves are processed on the surface of the baffle, each groove has a size of 0.1 mm to 2 mm, and the distance between two adjacent grooves is 3 mm to 5 mm, so as to increase the contact and reaction area between the sodium persulfate aqueous solution and the baffle.

[0014] The method for removing olefins, alkynes and cyclic hydrocarbon impurities from halogenated hydrocarbons based on the removal device of the present invention comprises the following steps:

[0015] (1) using an external vacuum pumping device to replace the removal device with nitrogen or an inert gas for more than two times, so that the water content of the removal device is less than 0.5 ppm, and finally the removal device is vacuumed to below -0.095 MPa;

[0016] (2) firstly adding a sodium persulfate aqueous solution with a mass fraction of 10% to 60% in a sodium persulfate storage tank into an oxidation tower; then adding a crude halogenated hydrocarbon product in a halogenated hydrocarbon storage tank into the oxidation tower, and the halogenated hydrocarbon product is baffled by a baffle plate inside the oxidation tower, and the sodium persulfate aqueous solution is fully contacted with the baffle plate and the crude halogenated hydrocarbon product to react so as to remove olefins, alkynes and cyclic hydrocarbon impurities in the halogenated hydrocarbon, that is, the strong oxidizing free radicals generated by the reaction of the sodium persulfate aqueous solution with the baffle plate undergo an oxidation-reduction reaction with the olefins, alkynes and cyclic hydrocarbon impurities in the halogenated hydrocarbon, so as to convert the olefins, alkynes and cyclic hydrocarbon impurities in the halogenated hydrocarbon that are difficult to separate into organic or inorganic small molecules that are easy to remove;

[0017] (3) The gas coming out of the upper part of the oxidation tower enters the adsorption tower for adsorption, wherein the working temperature of the adsorption tower is -10°C to 10°C and the working pressure is 0.05MPa to 0.3MPa, and some impurities are initially removed;

[0018] (4) The gas coming out from the upper part of the adsorption tower enters the purification tower for distillation and purification, wherein the working temperature of the purification tower is -30°C to 35°C and the working pressure is 0.05MPa to 1.0MPa, and halogenated hydrocarbons with a purity of more than 99.999vol% are collected from the halogenated hydrocarbon discharge pipe.

[0019] Furthermore, the temperature of the replacement treatment in step (1) is 60°C to 150°C.

[0020] Furthermore, the mass fraction of the sodium persulfate aqueous solution is 20% to 40%.

[0021] Furthermore, the flow ratio of the sodium persulfate aqueous solution to the halogenated hydrocarbon crude product entering the oxidation tower is (1.5-3):1.

[0022] Furthermore, the impurity content in the crude halogenated hydrocarbon is 100 ppm to 2×10 5 ppm.

[0023] Furthermore, the halogenated hydrocarbon is hexafluoroethane, octafluoropropane or octafluorocyclobutane; the olefin, alkyne and cyclic hydrocarbon impurities in the halogenated hydrocarbon are at least one of hexafluoropropylene, hexafluorocyclopropane, octafluoroisobutylene, octafluoro-1-butene, perfluoropropyne and tetrafluoroethylene.

[0024] Beneficial effects:

[0025] (1) The removal device of the present invention comprises an oxidation tower, an adsorption tower and a purification tower. By combining the oxidation process, the adsorption process and the distillation process, halogenated hydrocarbons with a purity of more than 99.999 vol% are obtained. The removal device has a simple structure, low investment, low operating energy consumption, and is easy to realize industrial production.

[0026] (2) In the removal method of the present invention, strong oxidizing free radicals generated by the reaction of sodium persulfate aqueous solution with a baffle made of transition metal material can thoroughly, quickly and efficiently oxidize the difficult-to-separate olefins, alkynes and cyclic hydrocarbon impurities in halogenated hydrocarbons into easily removable organic or inorganic small molecule impurities, which are then removed by adsorption and distillation, effectively reducing the difficulty of the adsorption process and the distillation process, and greatly improving the operability of the adsorption process and the distillation process. This removal method solves the problem that olefins, alkynes and cyclic hydrocarbon impurities in halogenated hydrocarbons are difficult to remove, and obtains halogenated hydrocarbons with a purity of more than 99.999 vol%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the device structure used to remove olefins, alkynes and cyclic hydrocarbon impurities in halogenated hydrocarbons in the examples.

[0028] Among them, 1-halogenated hydrocarbon storage tank, 2-halogenated hydrocarbon feed pipe, 3-halogenated hydrocarbon feed valve, 4-gas distributor, 5-baffle, 6-oxidation tower, 7-oxidation tower discharge valve, 8-adsorption tower feed pipe, 9-adsorption tower, 10-adsorption tower discharge valve, 11-purification tower feed pipe, 12-drain valve, 13-drain pipe, 14-sodium persulfate storage tank, 15-sodium persulfate feed valve, 16-inert gas pipe, 17-inert gas valve, 18-vacuum tube, 19-vacuum valve, 20-flow meter, 21-second thermometer, 22-second pressure gauge, 23-first thermometer, 24-purification tower, 25-purification tower feed valve, 26-third thermometer, 27-third pressure gauge, 28-discharge analysis valve, 29-discharge analysis pipe, 30-discharge valve of purification tower, 31-discharge pipe of halogenated hydrocarbon, 32-feed pipe of sodium persulfate. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with specific embodiments, wherein the methods are conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified. In addition, in the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0030] In the following embodiments, the device used to remove olefins, alkynes and cyclic hydrocarbon impurities in halogenated hydrocarbons includes a sodium persulfate storage tank 14, a halogenated hydrocarbon storage tank 1, an oxidation tower 6, an adsorption tower 9 and a purification tower 24, such as Figure 1 As shown;

[0031] The oxidation tower 6 is provided with a baffle 5 and a gas distributor 4 inside, and the gas distributor 4 is installed below the baffle 5, the baffle 5 is a transition metal plate (the following embodiment selects one of an iron plate, a manganese plate, a copper plate or a nickel plate), and the baffle 5 is also processed with grooves, the size of each groove is 0.1mm-2mm, and the distance between two adjacent grooves is 3mm-5mm; the upper part of the oxidation tower 6 is provided with a liquid inlet and a gas outlet, and the lower part is provided with an air inlet (or a liquid discharge port, in this case, the air inlet and the liquid discharge port share a port);

[0032] The adsorption tower 9 removes some impurities in the halogenated hydrocarbons by physical adsorption; the adsorption tower 9 is filled with an adsorbent, such as commonly used activated carbon, aluminum oxide and solid alkali, etc. In the following embodiments, activated carbon is used as the adsorbent; the lower part of the adsorption tower 9 is provided with an air inlet, and the upper part is provided with an air outlet;

[0033] The purification tower 24 removes some impurities in the halogenated hydrocarbons by distillation; the purification tower 24 is filled with fillers, such as commonly used θ rings, ball rings, Raschig rings and structured packings, etc., and θ rings are used as fillers in the following embodiments; the purification tower 24 is provided with an air inlet at the bottom and an air outlet at the top;

[0034] The sodium persulfate storage tank 14 is connected to the liquid inlet of the oxidation tower 6 through a sodium persulfate feed pipe 32, and a sodium persulfate feed valve 15 is installed on the sodium persulfate feed pipe 32; the halogenated hydrocarbon storage tank 1 is connected to the air inlet of the oxidation tower 6 through a halogenated hydrocarbon feed pipe 2, and a flow meter 20 and a halogenated hydrocarbon feed valve 3 are installed on the halogenated hydrocarbon feed pipe 2 in sequence according to the gas flow direction; the air inlet of the oxidation tower 6 is also connected to a drain pipe 13, and a drain valve 12 is installed on the drain pipe 13; the air outlet of the oxidation tower 6 The gas inlet of the adsorption tower 9 is connected through the adsorption tower feed pipe 8, and the adsorption tower feed pipe 8 is equipped with an oxidation tower discharge valve 7; the gas outlet of the adsorption tower 9 is connected to the gas inlet of the purification tower 24 through the purification tower feed pipe 11, and the adsorption tower discharge valve 10 and the purification tower feed valve 25 are installed on the purification tower feed pipe 11 in sequence according to the gas flow direction; the gas outlet of the adsorption tower 9 is also connected to the vacuum tube 18 and the inert gas tube 16, and the vacuum tube 18 is equipped with a vacuum valve 19, and the inert gas tube 16 An inert gas valve 17 is installed on it; the gas outlet of the purification tower 24 is connected to a halogenated hydrocarbon discharge pipe 31, and a purification tower discharge valve 30 is installed on the halogenated hydrocarbon discharge pipe 31; the gas outlet of the purification tower 24 is also connected to a discharge analysis pipe 29, and a discharge analysis valve 28 is installed on the discharge analysis pipe 29; the oxidation tower 6 is also installed with a first thermometer 23, the adsorption tower 9 is also installed with a second thermometer 21 and a second pressure gauge 22, and the purification tower 24 is also installed with a third thermometer 26 and a third pressure gauge 27.

[0035] The water content in the following examples is tested in accordance with the national standard GB / T5832.1-2003 "Determination of humidity in gases - Part 1 - Electrolytic method".

[0036] Example 1

[0037] Octafluoropropane with an impurity content of 100 ppm is used as a crude halogenated hydrocarbon, wherein the impurities are hexafluoropropylene and hexafluorocyclopropane; the baffle 5 is processed with regular hexagonal grooves, the side length of the regular hexagon is 0.1 mm, and the distance between two adjacent grooves is 3 mm; the specific operation of using the above device to remove impurities in the crude halogenated hydrocarbon described in this embodiment is as follows:

[0038] (1) connecting an external vacuum pump to the vacuum tube 18, connecting an external nitrogen cylinder to the inert gas tube 16, setting the temperatures of the oxidation tower 6, the adsorption tower 9 and the purification tower 24 to 60° C., using the vacuum pump, performing a nitrogen replacement treatment on the device for three times, so that the water content of the device is less than 0.5 ppm, and finally evacuating the device to below -0.095 MPa;

[0039] (2) firstly open the sodium persulfate feed valve 15, and add the sodium persulfate aqueous solution with a mass fraction of 20% in the sodium persulfate storage tank 14 to the oxidation tower 6 at a flow rate of 15 L / min; then open the halogenated hydrocarbon feed valve 3, and add the halogenated hydrocarbon crude product in the halogenated hydrocarbon storage tank 1 to the oxidation tower 6 at a flow rate of 10 L / min. After being baffled layer by layer by the baffle plates 5 inside the oxidation tower 6, the sodium persulfate aqueous solution fully contacts and reacts with the baffle plates 5 and the halogenated hydrocarbon crude product, and the olefins, alkynes and cyclic hydrocarbon impurities that are difficult to separate in the halogenated hydrocarbons are converted into organic or inorganic small molecular impurities that are easy to remove;

[0040] (3) The gas coming out of the upper part of the oxidation tower 6 enters the adsorption tower 9 for adsorption, wherein the working temperature of the adsorption tower 9 is -10°C and the working pressure is 0.05MPa, and some impurities are initially removed;

[0041] (4) The gas coming out from the upper part of the adsorption tower 9 enters the purification tower 24 for distillation and purification, wherein the working temperature of the purification tower 24 is -30°C and the working pressure is 0.05 MPa, and the halogenated hydrocarbons output from the halogenated hydrocarbon discharge pipe 31 are collected; wherein, samples are taken from the discharge analysis pipe 29 for analysis, and the contents of hexafluorocyclopropane, hexafluoropropylene and other impurities are less than the instrument detection limit, and the total content of other inorganic impurities such as hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, etc. is 0.8 ppm, so the purity of the collected halogenated hydrocarbons reaches 99.999 vol% or more.

[0042] Example 2

[0043] With an impurity content of 2×10 5 ppm of octafluorocyclobutane as the crude halogenated hydrocarbon, wherein the impurities are octafluoroisobutylene and octafluoro-1-butene; the baffle 5 is processed with a regular hexagonal groove, the side length of the regular hexagon is 1 mm, and the distance between two adjacent grooves is 5 mm; the specific operation of removing impurities from the crude halogenated hydrocarbon described in this embodiment using the above device is as follows:

[0044] (1) connecting an external vacuum pump to the vacuum tube 18, connecting an external nitrogen cylinder to the inert gas tube 16, setting the temperatures of the oxidation tower 6, the adsorption tower 9 and the purification tower 24 to 150° C., using the vacuum pump, performing a nitrogen replacement treatment on the device for 5 times, so that the water content of the device is less than 0.5 ppm, and finally evacuating the device to below -0.095 MPa;

[0045] (2) firstly opening the sodium persulfate feed valve 15, and adding the sodium persulfate aqueous solution with a mass fraction of 60% in the sodium persulfate storage tank 14 to the oxidation tower 6 at a flow rate of 1500 L / min; then opening the halogenated hydrocarbon feed valve 3, and adding the halogenated hydrocarbon crude product in the halogenated hydrocarbon storage tank 1 to the oxidation tower 6 at a flow rate of 500 L / min, and the sodium persulfate aqueous solution is fully contacted and reacted with the baffles 5 and the halogenated hydrocarbon crude product after being baffled layer by layer by the internal baffles 5 of the oxidation tower 6, so that the olefins, alkynes and cyclic hydrocarbon impurities in the halogenated hydrocarbons that are difficult to separate are converted into organic or inorganic small molecular impurities that are easy to remove;

[0046] (3) The gas coming out of the upper part of the oxidation tower 6 enters the adsorption tower 9 for adsorption, wherein the working temperature of the adsorption tower 9 is 10° C. and the working pressure is 0.3 MPa, and some impurities are initially removed;

[0047] (4) The gas coming out from the upper part of the adsorption tower 9 enters the purification tower 24 for distillation and purification, wherein the working temperature of the purification tower 24 is 35° C. and the working pressure is 0.32 MPa, and the halogenated hydrocarbons output from the halogenated hydrocarbon discharge pipe 31 are collected; wherein, samples are taken from the discharge analysis pipe 29 for analysis, and the contents of octafluoroisobutylene, octafluoro-1-butene and other impurities are less than the instrument detection limit, and the total content of other inorganic impurities such as hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, etc. is 1.2 ppm, so the purity of the collected halogenated hydrocarbons reaches 99.999 vol% or more.

[0048] Example 3

[0049] Taking the impurity content as 1×10 4 ppm of hexafluoroethane as the crude halogenated hydrocarbon, wherein the impurities are hexafluoropropylene and tetrafluoroethylene; the baffle 5 is processed with a regular hexagonal groove, the side length of the regular hexagon is 0.5 mm, and the distance between two adjacent grooves is 4 mm; the specific operation of removing impurities from the crude halogenated hydrocarbon described in this embodiment using the above device is as follows:

[0050] (1) connecting an external vacuum pump to the vacuum tube 18, connecting an external nitrogen cylinder to the inert gas tube 16, setting the temperatures of the oxidation tower 6, the adsorption tower 9 and the purification tower 24 to 100° C., using the vacuum pump, performing a nitrogen replacement treatment on the device 4 times, so that the water content of the device is less than 0.5 ppm, and finally evacuating the device to below -0.095 MPa;

[0051] (2) firstly open the sodium persulfate feed valve 15, and add the sodium persulfate aqueous solution with a mass fraction of 40% in the sodium persulfate storage tank 14 to the oxidation tower 6 at a flow rate of 500 L / min; then open the halogenated hydrocarbon feed valve 3, and add the halogenated hydrocarbon crude product in the halogenated hydrocarbon storage tank 1 to the oxidation tower 6 at a flow rate of 250 L / min. After being baffled layer by layer by the baffle plates 5 inside the oxidation tower 6, the sodium persulfate aqueous solution fully contacts and reacts with the baffle plates 5 and the halogenated hydrocarbon crude product, and the olefins, alkynes and cyclic hydrocarbon impurities that are difficult to separate in the halogenated hydrocarbons are converted into organic or inorganic small molecular impurities that are easy to remove;

[0052] (3) The gas coming out of the upper part of the oxidation tower 6 enters the adsorption tower 9 for adsorption, wherein the working temperature of the adsorption tower 9 is 0° C. and the working pressure is 0.15 MPa, and some impurities are initially removed;

[0053] (4) The gas coming out from the upper part of the adsorption tower 9 enters the purification tower 24 for distillation and purification, wherein the working temperature of the purification tower 24 is -19°C and the working pressure is 1.0 MPa, and the halogenated hydrocarbons output from the halogenated hydrocarbon discharge pipe 31 are collected; wherein, samples are taken from the discharge analysis pipe 29 for analysis, and the contents of tetrafluoroethylene, hexafluoropropylene and other impurities are less than the instrument detection limit, and the total content of other inorganic impurities such as hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, etc. is 1.5 ppm, so the purity of the collected halogenated hydrocarbons reaches more than 99.999 vol%.

[0054] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for removing olefins, alkynes and cyclic hydrocarbon impurities from halogenated hydrocarbons, characterized in that: The device used in the method is a device for removing olefin, alkyne and cyclic hydrocarbon impurities in halogenated hydrocarbons, and the device comprises a sodium persulfate storage tank, a halogenated hydrocarbon storage tank, an oxidation tower, an adsorption tower and a purification tower; The oxidation tower is provided with a baffle plate inside, and the baffle plate is a transition metal plate; the upper part of the oxidation tower is provided with a liquid inlet and a gas outlet, and the lower part is provided with a gas inlet and a liquid discharge port; The adsorption tower removes some impurities in the halogenated hydrocarbons by physical adsorption; the lower part of the adsorption tower is provided with an air inlet, and the upper part is provided with an air outlet; The purification tower removes some impurities in the halogenated hydrocarbons by distillation; the purification tower is provided with an air inlet at the bottom and an air outlet at the top; The sodium persulfate storage tank is connected to the liquid inlet of the oxidation tower, the halogenated hydrocarbon storage tank is connected to the air inlet of the oxidation tower, the liquid discharge port of the oxidation tower is connected to a liquid discharge pipe, the air outlet of the oxidation tower is connected to the air inlet of the adsorption tower, the air outlet of the adsorption tower is connected to the air inlet of the purification tower, and the air outlet of the purification tower is connected to a halogenated hydrocarbon discharge pipe; The method steps are as follows: (1) using an external vacuum pumping device to replace the removal device with nitrogen or an inert gas for more than two times, so that the water content of the removal device is less than 0.5 ppm, and finally the removal device is vacuumed to below -0.095 MPa; (2) firstly adding a sodium persulfate aqueous solution with a mass fraction of 10% to 60% in a sodium persulfate storage tank into an oxidation tower; then adding a crude halogenated hydrocarbon product in a halogenated hydrocarbon storage tank into the oxidation tower, and the sodium persulfate aqueous solution is fully contacted and reacted with the baffle plate and the crude halogenated hydrocarbon product to remove olefins, alkynes and cyclic hydrocarbon impurities in the halogenated hydrocarbon after being baffled by the baffle plate inside the oxidation tower; (3) The gas coming out of the upper part of the oxidation tower enters the adsorption tower for adsorption, wherein the working temperature of the adsorption tower is -10°C to 10°C and the working pressure is 0.05MPa to 0.3MPa; (4) The gas coming out from the upper part of the adsorption tower enters the purification tower for distillation and purification, wherein the working temperature of the purification tower is -30°C to 35°C and the working pressure is 0.05MPa to 1.0MPa, and halogenated hydrocarbons with a purity of more than 99.999vol% are collected from the halogenated hydrocarbon discharge pipe.

2. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: The temperature of the replacement treatment in step (1) is 60°C to 150°C.

3. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: The mass fraction of the sodium persulfate aqueous solution is 20% to 40%.

4. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: The flow ratio of the sodium persulfate aqueous solution to the halogenated hydrocarbon crude product entering the oxidation tower is 1.5 to 3:

1.

5. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: The impurity content in the crude halogenated hydrocarbon is 100 ppm to 2×10 5 ppm.

6. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: The halogenated hydrocarbon is hexafluoroethane, octafluoropropane or octafluorocyclobutane; the olefin, alkyne and cyclic hydrocarbon impurities in the halogenated hydrocarbon are at least one of hexafluoropropylene, hexafluorocyclopropane, octafluoroisobutylene, octafluoro-1-butene, perfluoropropyne and tetrafluoroethylene.

7. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: A gas distributor is also provided at the bottom of the oxidation tower, and the gas distributor is located below the baffle.

8. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: The baffle is an iron plate, a manganese plate, a copper plate or a nickel plate.

9. The method for removing olefin, alkyne and cyclic hydrocarbon impurities from halogenated hydrocarbons according to claim 1, characterized in that: Grooves are processed on the surface of the baffle, the size of each groove is 0.1mm-2mm, and the distance between two adjacent grooves is 3mm-5mm.

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