CN118063283A - High purification method and high purification device for trifluoromethane - Google Patents
High purification method and high purification device for trifluoromethane Download PDFInfo
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- CN118063283A CN118063283A CN202211471076.3A CN202211471076A CN118063283A CN 118063283 A CN118063283 A CN 118063283A CN 202211471076 A CN202211471076 A CN 202211471076A CN 118063283 A CN118063283 A CN 118063283A
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- trifluoromethane
- tower
- difluoromethane
- recovery tower
- condenser
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- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 title claims abstract description 364
- 238000000746 purification Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title claims abstract description 13
- RWRIWBAIICGTTQ-UHFFFAOYSA-N difluoromethane Chemical compound FCF RWRIWBAIICGTTQ-UHFFFAOYSA-N 0.000 claims abstract description 86
- 239000000047 product Substances 0.000 claims abstract description 34
- 239000006227 byproduct Substances 0.000 claims abstract description 8
- 238000006243 chemical reaction Methods 0.000 claims abstract description 7
- 239000002912 waste gas Substances 0.000 claims abstract description 5
- 238000011084 recovery Methods 0.000 claims description 69
- 238000012856 packing Methods 0.000 claims description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 30
- 239000012267 brine Substances 0.000 claims description 21
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims description 21
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 16
- VOPWNXZWBYDODV-UHFFFAOYSA-N Chlorodifluoromethane Chemical compound FC(F)Cl VOPWNXZWBYDODV-UHFFFAOYSA-N 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 16
- 239000003507 refrigerant Substances 0.000 claims description 16
- 239000003513 alkali Substances 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 15
- 239000007789 gas Substances 0.000 claims description 13
- 229910001220 stainless steel Inorganic materials 0.000 claims description 12
- 239000010935 stainless steel Substances 0.000 claims description 12
- 238000003860 storage Methods 0.000 claims description 12
- 238000004064 recycling Methods 0.000 claims description 9
- 239000001569 carbon dioxide Substances 0.000 claims description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 8
- 230000006835 compression Effects 0.000 claims description 7
- 238000007906 compression Methods 0.000 claims description 7
- 238000009833 condensation Methods 0.000 claims description 7
- 230000005494 condensation Effects 0.000 claims description 7
- 229910000831 Steel Inorganic materials 0.000 claims description 6
- -1 polyethylene Polymers 0.000 claims description 6
- 239000010959 steel Substances 0.000 claims description 6
- 238000007599 discharging Methods 0.000 claims description 5
- 238000010992 reflux Methods 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 3
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 claims description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 229920000573 polyethylene Polymers 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 3
- 230000001105 regulatory effect Effects 0.000 claims description 3
- 239000011780 sodium chloride Substances 0.000 claims description 3
- RZSJYVBYLBNFGQ-UHFFFAOYSA-N difluoromethane hydrochloride Chemical compound FCF.Cl RZSJYVBYLBNFGQ-UHFFFAOYSA-N 0.000 claims 2
- 238000002203 pretreatment Methods 0.000 claims 1
- 238000000926 separation method Methods 0.000 abstract description 7
- 238000005265 energy consumption Methods 0.000 abstract description 2
- 230000001276 controlling effect Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009965 odorless effect Effects 0.000 description 2
- 239000003380 propellant Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 125000002023 trifluoromethyl group Chemical group FC(F)(F)* 0.000 description 2
- MALIONKMKPITBV-UHFFFAOYSA-N 2-(3-chloro-4-hydroxyphenyl)-n-[2-(4-sulfamoylphenyl)ethyl]acetamide Chemical compound C1=CC(S(=O)(=O)N)=CC=C1CCNC(=O)CC1=CC=C(O)C(Cl)=C1 MALIONKMKPITBV-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000000194 supercritical-fluid extraction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a high purification method and a high purification device of trifluoromethane, which can recycle the by-product waste gas trifluoromethane in a reaction tower for preparing difluoromethane, thereby obtaining high-purity trifluoromethane, simplifying the separation process, reducing the separation difficulty and eliminating the need of incineration treatment of the trifluoromethane; and the energy consumption can be effectively reduced, and the purity of the product R23 can reach 99.9 percent.
Description
Technical Field
The invention belongs to the technical field of refining and purifying of trifluoromethane, and relates to a high-purity method and a high-purity device of trifluoromethane.
Background
Trifluoromethane R23 is a colorless, slightly flavored, nonconductive gas of broad utility and stable chemical properties, of the formula CHF3, which is primarily useful as a refrigerant, fire extinguishing agent, and etchant. In addition, CHF3 is one of the basic raw materials for fluoride organic synthesis, is also a supercritical extraction solvent, and can be used as a direct coolant for an infrared detector or used as a propellant to be mixed with other nonflammable propellants for physical and chemical experiments and the like. As an etchant in the semiconductor and microelectronics industries, the purity of CHF3 is critical. CHF3 of high purity is a guarantee for the fabrication of high-level, high-quality silicon wafers. But the trifluoromethyl is mainly derived from byproducts generated in the production and preparation process of the difluoro chloromethane, and the byproducts account for about 1.5-3% (w%) of the content of R22. The raw materials contain more oxygen, nitrogen, carbon dioxide, R22, R21, R23, H 2 O and the like. Wherein the boiling point and the property of the trifluoromethane are very similar to those of the carbon dioxide, and the trifluoromethane and the carbon dioxide are easy to form an azeotrope, so that the separation difficulty is high.
Disclosure of Invention
The invention provides a high purification method and a high purification device for trifluoromethane, which can purify byproduct trifluoromethane in difluoromethane step by step, thereby obtaining high-purity trifluoromethane, simplifying the separation process and reducing the separation difficulty.
The invention adopts the following technical scheme: a process for highly purifying trifluoromethane comprising the steps of:
Firstly, discharging waste gas of the byproduct in a reaction tower for preparing difluoro chloromethane, and then collecting and storing the discharged trifluoro methane by a trifluoro methane buffer tank after the trifluoro methane sequentially passes through pretreatment of a light component removal tower and a water alkali washing tower through a gas transmission pipeline;
Step two, the pretreated trifluoromethane stored in the trifluoromethane buffer tank is subjected to two-stage compression by a compressor and two-stage condensation in a front condenser, and then is collected by a trifluoromethane middle tank;
step three, the gas of the trifluoromethane in the middle tank of the trifluoromethane is conveyed to a difluoromethane recovery tower through a material conveying pump, and the difluoromethane and the trifluoromethane are separated;
And step four, utilizing the refined trifluoromethane separated in the step three of the trifluoromethane recovery tower, discharging the trifluoromethane from the top of the trifluoromethane recovery tower, condensing the trifluoromethane by a trifluoromethane condenser to obtain a high-purity trifluoromethane finished product, and collecting the high-purity trifluoromethane finished product in a trifluoromethane finished product storage tank.
Further, in the first step, the pressure of the light component removing tower is controlled to be 1.5-1.8 MPa, the temperature of the top of the light component removing tower is controlled to be-14 to-20 ℃, and the temperature of the bottom of the light component removing tower is controlled to be 20-40 ℃.
Further, circulating water, cold water at 0 ℃, brine at-15 ℃ or brine at-35 ℃ is selected when secondary compression is carried out in the compressor, and cold water at 0 ℃, brine at-15 ℃ or brine at-35 ℃ is selected when secondary condensation is carried out in the pre-condenser.
Further, in the third step, the difluoromethane and the trifluoromethane are separated by a difluoromethane recovery tower, the pressure of the difluoromethane recovery tower is controlled to be 1.5-1.8 MPa, the temperature of the top of the difluoromethane recovery tower is controlled to be minus 15-10 ℃, the temperature of the bottom of the difluoromethane recovery tower is controlled to be 20-30 ℃, the reflux ratio of the difluoromethane recovery tower is controlled to be 50-100, the refrigerant in the difluoromethane recovery tower adopts brine at minus 35 ℃, and the bottom of the difluoromethane recovery tower is heated by steam or hot water.
In the fourth step, the pressure of the trifluoromethane recovery tower is controlled to be 1.2-1.5 MPa, the temperature of the top of the trifluoromethane recovery tower is controlled to be minus 25-minus 15 ℃, the temperature of the bottom of the trifluoromethane recovery tower is controlled to be minus 20-minus 10 ℃, the purity of the high-purity trifluoromethane finished product reaches 99.9%, the carbon dioxide content in the high-purity trifluoromethane finished product is less than or equal to 50ppm, the moisture is less than or equal to 10ppm, the acidity is less than or equal to 0.1ppm, and the refrigerant of the trifluoromethane condenser is selected to be saline water at minus 35 ℃. The refrigerant of the trifluoromethane recovery tower adopts brine at minus 35 ℃, and the refrigerant at +3deg.C is selected from the tower bottom of the trifluoromethane recovery tower.
The invention also discloses a high purification device for the trifluoromethane, which is characterized by mainly comprising a light removal tower, a water-alkali washing tower, a trifluoromethane buffer tank, a compressor, a preposed condenser, a trifluoromethane middle tank, a material conveying pump, a difluoromethane recovery tower, a trifluoromethane condenser and a trifluoromethane finished product storage tank, wherein the reaction tower for preparing the difluoromethane is communicated with the side inlet of the light removal tower through a gas conveying pipeline, the top outlet of the light removal tower is communicated with the inlet of the water-alkali washing tower, the outlet of the water-alkali washing tower is communicated with the side inlet of the trifluoromethane buffer tank, the bottom outlet of the trifluoromethane buffer tank is communicated with the inlet on one side of the trifluoromethane middle tank through the compressor and the preposed condenser in sequence, the outlet on one side of the trifluoromethane middle tank is communicated with the side inlet of the difluoromethane recovery tower through the material conveying pump, and the top outlet of the difluoromethane recovery tower is communicated with the side inlet of the trifluoromethane finished product storage tank through the trifluoromethane condenser.
Further, the light component removing tower is arranged as a packing tower, and the packing I in the packing tower is stainless steel pall ring packing, stainless steel saddle ring packing or regular silk screen packing.
Further, the water alkali washing tower adopts steel lining equipment, and lining materials of the steel lining equipment are propylene oxide, polyethylene or polytetrafluoroethylene; the water wash column can also be a tray column.
Further, a material cut-off valve is arranged on a feeding pipeline of the trifluoromethane buffer tank, a buffer safety valve is arranged in the trifluoromethane buffer tank, a pressure transmitter I is arranged at the top of the trifluoromethane buffer tank and used for monitoring the pressure of the buffer tank, a pressure regulating valve is arranged between an outlet at the bottom of the trifluoromethane buffer tank and an inlet of a compressor, a pressure transmitter II and a temperature transmitter I are sequentially arranged on a pipeline of the outlet of the compressor, jackets are arranged outside the trifluoromethane buffer tank, a trifluoromethane intermediate tank and a trifluoromethane finished product storage tank, and a temperature transmitter II is arranged on the jackets.
Further, the difluoro chloromethane recovery tower and the trifluoro methane recovery tower adopt a packing tower, and the packing II of the packing tower is stainless steel pall ring packing, stainless steel saddle ring packing or regular silk screen packing.
Further, the front condenser and the trifluoromethane condenser are tube type coolers or high-efficiency spiral heat exchangers.
The invention has the following beneficial effects: after the technical scheme is adopted, the device and the method can recycle the waste gas of the byproduct, namely the trifluoromethane, in the reaction tower for preparing the difluoromethane, so that the high-purity trifluoromethane can be obtained, the separation process is simplified, the separation difficulty is reduced, and the trifluoromethane does not need to be subjected to incineration treatment; and the energy consumption can be effectively reduced, and the purity of the product R23 can reach 99.9 percent.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural view of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making clear and defining the scope of the present invention.
The invention provides a high purification method of trifluoromethane, which comprises the following steps: firstly, discharging waste gas of a byproduct in a reaction tower 11 for preparing difluoro chloromethane, then pretreating the discharged trifluoro methane sequentially through a light component removing tower 1 and a water alkali washing tower 2 by a gas pipeline 12, collecting and storing the trifluoro methane by a trifluoro methane buffer tank 3, controlling the pressure of the light component removing tower 1 at 1.5-1.8 MPa, controlling the temperature of the tower top of the light component removing tower 1 at-14 to-20 ℃, controlling the temperature of the tower bottom of the light component removing tower 1 at 20-40 ℃, controlling the pressure of the light component removing tower 1 at 1.5MPa, controlling the temperature of the tower top of the light component removing tower 1 at-14 ℃, the temperature of the tower bottom of the light component removing tower 1 is controlled at 20 ℃; step two, the pre-treated trifluoromethane stored in the trifluoromethane buffer tank 3 is subjected to two-stage compression by a compressor 4 and two-stage condensation in a pre-condenser 5, then is collected again by a trifluoromethane middle tank 6, circulating water, cold water at 0 ℃, brine at 15 ℃ or brine at 35 ℃ below zero are selected when the two-stage compression is performed in the compressor 4, cold water at 0 ℃, brine at 15 ℃ or brine at 35 ℃ below zero are selected when the two-stage condensation is performed in the pre-condenser 5, cold water at 0 ℃ is selected when the two-stage compression is performed in the compressor 4, and cold water at 0 ℃ is selected when the two-stage condensation is performed in the pre-condenser 5; step three, the trifluoromethane gas in the trifluoromethane intermediate tank 6 is conveyed to a difluoromethane recovery tower 7 through a material conveying pump 23, the difluoromethane and the trifluoromethane are separated, the difluoromethane is separated by the difluoromethane recovery tower 7, the pressure of the difluoromethane recovery tower 7 is controlled to be 1.5-1.8 MPa, the temperature of the top of the difluoromethane recovery tower 7 is controlled to be minus 15 to minus 10 ℃, the temperature of the bottom of the difluoromethane recovery tower 7 is controlled to be 20-30 ℃, the reflux ratio of the difluoromethane recovery tower 7 is controlled to be 50-100, the refrigerant in the difluoromethane recovery tower 7 adopts brine at minus 35 ℃, the steam heating or hot water heating is selected for the tower bottom of the difluoro chloromethane recovery tower 7, the difluoro chloromethane recovery tower 7 is used for separating difluoro chloromethane and trifluoromethyl, the pressure of the difluoro chloromethane recovery tower 7 is controlled to be 1.5MPa, the temperature of the tower top of the difluoro chloromethane recovery tower 7 is controlled to be minus 15 ℃, the temperature of the tower bottom of the difluoro chloromethane recovery tower 7 is controlled to be 20 ℃, the reflux ratio of the difluoro chloromethane recovery tower 7 is controlled to be 50, brine at minus 35 ℃ is adopted for the refrigerant in the difluoro chloromethane recovery tower 7, and the steam heating or hot water heating is selected for the tower bottom of the difluoro chloromethane recovery tower 7; step four, refined trifluoromethane separated in the step three of a trifluoromethane recovery tower 8 is utilized, the trifluoromethane is discharged from the top of the trifluoromethane recovery tower 8, a high-purity trifluoromethane finished product is obtained after the material is condensed by a trifluoromethane condenser 9, the high-purity trifluoromethane finished product is collected in a trifluoromethane finished product storage tank 10, the pressure of the trifluoromethane recovery tower 8 is controlled to be 1.2-1.5 MPa, the temperature of the top of the trifluoromethane recovery tower 8 is controlled to be minus 25-minus 15 ℃, the temperature of the bottom of the trifluoromethane recovery tower 8 is controlled to be minus 20-minus 10 ℃, the purity of the high-purity trifluoromethane finished product reaches 99.9%, and the carbon dioxide content in the high-purity trifluoromethane finished product is less than or equal to 50ppm, the water content is less than or equal to 10ppm, the acidity is less than or equal to 0.1ppm, and the refrigerant of the trifluoromethane condenser 9 is brine at minus 35 ℃. The refrigerant of the trifluoromethane recovery tower 8 adopts brine at minus 35 ℃, the tower bottom of the trifluoromethane recovery tower 8 selects refrigerant at +3deg.C, the pressure of the trifluoromethane recovery tower 8 is controlled at 1.2MPa, the temperature of the tower top of the trifluoromethane recovery tower 8 is controlled at minus 25 ℃, the temperature of the tower bottom of the trifluoromethane recovery tower 8 is controlled at minus 20 ℃, the purity of the high-purity trifluoromethane product reaches 99.9%, the carbon dioxide content in the high-purity trifluoromethane product is less than or equal to 50ppm, the water content is less than or equal to 10ppm, the acidity is less than or equal to 0.1ppm, and the refrigerant of the trifluoromethane condenser 9 selects brine at minus 35 ℃. The refrigerant of the trifluoromethane recovery tower 8 adopts brine at minus 35 ℃, and the tower bottom of the trifluoromethane recovery tower 8 selects refrigerant at +3℃.
The invention also discloses a high purification device of the trifluoromethane, which mainly comprises a light component removing tower 1, a water-alkali washing tower 2, a trifluoromethane buffer tank 3, a compressor 4, a pre-condenser 5, a trifluoromethane intermediate tank 6, a material conveying pump 23, a difluoromethane recycling tower 7, a trifluoromethane recycling tower 8, a trifluoromethane condenser 9 and a trifluoromethane finished product storage tank 10, wherein the prepared difluoromethane recycling tower 11 is communicated with the side inlet of the light component removing tower 1 through a gas transmission pipeline 12, the top outlet of the light component removing tower 1 is communicated with the inlet of the water-alkali washing tower 2, the outlet of the water-alkali washing tower 2 is communicated with the side inlet of the trifluoromethane buffer tank 3, the bottom outlet of the trifluoromethane buffer tank 3 is communicated with the inlet on one side of the trifluoromethane intermediate tank 6 through the compressor 4 and the pre-condenser 5, the outlet on one side of the trifluoromethane intermediate tank 6 is communicated with the side inlet of the difluoromethane recycling tower 7 through the material conveying pump 23, the top outlet of the difluoromethane recycling tower 7 is communicated with the side inlet of the trifluoromethane finished product recycling tower 8, and the top outlet of the trifluoromethane recycling tower 8 is communicated with the side inlet of the trifluoromethane finished product storage tank 10 through the trifluoromethane recycling tower 9.
The light component removal tower 1 of the embodiment is set as a packing tower, and a packing I22 in the packing tower is stainless steel pall ring packing, stainless steel saddle ring packing or regular silk screen packing, and the water alkali washing tower 2 of the embodiment adopts steel lining equipment, and lining materials of the steel lining equipment are propylene oxide, polyethylene or polytetrafluoroethylene; the material cut-off valve 13 is arranged on the feeding pipe of the trifluoromethane buffer tank 3, the buffer safety valve 14 is arranged in the trifluoromethane buffer tank 3, the pressure transmitter I15 is arranged at the top of the trifluoromethane buffer tank 3, the pressure transmitter 15 is used for monitoring the pressure of the buffer tank, the pressure regulating valve 16 is arranged between the outlet at the bottom of the trifluoromethane buffer tank 3 and the inlet of the compressor 4, the pressure transmitter II 17 and the temperature transmitter I18 are sequentially arranged on the pipeline at the outlet of the compressor 4, jackets 19 are arranged outside the trifluoromethane buffer tank 3, the trifluoromethane intermediate tank 6 and the trifluoromethane finished product storage tank 10, the temperature transmitter II 20 is arranged on the jackets 19, the difluoromethane recovery tower 11 and the trifluoromethane recovery tower 8 of the embodiment adopt a packing tower, the packing II 21 of the packing tower is stainless steel pall ring packing, stainless steel rectangular saddle ring packing or regular silk screen packing, and the front condenser 5 and the trifluoromethane condenser 9 of the embodiment are tubular coolers or high-efficiency spiral heat exchangers.
The process control and the finished product detection of the invention are obtained by gas chromatography analysis, and the analysis results of the finished product of the trifluoromethane are shown as follows:
Table-results of product quality analysis:
| Sequence number | Index name | Index unit | Superior product | Qualified product |
| 1 | Appearance smell | Colorless transparent odorless | Colorless transparent odorless | |
| 2 | Purity of | % | ≥ 99.9 | ≥ 99.8 |
| 3 | Moisture content | PPm | ≤ 10 | ≤ 20 |
| 4 | Acidity (in HCL) | PPm | ≤ 0.1 | ≤ 1 |
| 5 | Carbon dioxide | PPm | ≤ 30 | ≤ 50 |
| 6 | Non-condensable gas in gas phase | % | --- |
Without being limited thereto, any changes or substitutions that are not contemplated by the inventors are intended to be included within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.
Claims (10)
1. A process for highly purifying trifluoromethane comprising the steps of:
Firstly, discharging waste gas of the by-product gas in a reaction tower (11) for preparing the difluoro chloromethane, and then collecting and storing the discharged trifluoro methane by a trifluoro methane buffer tank (3) after the pre-treatment of a light component removal tower (1) and a water alkali washing tower (2) sequentially through a gas transmission pipeline (12);
Step two, the pre-treated trifluoromethane stored in the trifluoromethane buffer tank (3) is subjected to two-stage compression by the compressor (4) and two-stage condensation in the pre-condenser (5), and then is collected by the trifluoromethane intermediate tank (6);
step three, the trifluoromethane gas in the trifluoromethane intermediate tank (6) is conveyed to a difluoromethane-chloride recovery tower (7) through a material conveying pump (23) to separate difluoromethane-chloride and trifluoromethane;
And step four, utilizing the refined trifluoromethane separated in the step three of the trifluoromethane recovery tower (8), discharging the trifluoromethane from the top of the trifluoromethane recovery tower (8), condensing the trifluoromethane by a trifluoromethane condenser (9) to obtain a high-purity trifluoromethane finished product, and collecting the high-purity trifluoromethane finished product in a trifluoromethane finished product storage tank (10).
2. The method for purifying high-purity trifluoromethane according to claim 1, wherein in the first step, the pressure of the light component removing column (1) is controlled to be 1.5-1.8 MPa, the temperature of the top of the light component removing column (1) is controlled to be-14 to-20 ℃, and the temperature of the bottom of the light component removing column (1) is controlled to be 20-40 ℃.
3. The method for purifying high-purity trifluoromethane according to claim 1, wherein the compressor (4) is internally provided with circulating water, cold water at 0 ℃, brine at-15 ℃ or brine at-35 ℃ during secondary compression, and the pre-condenser (5) is internally provided with cold water at 0 ℃, brine at-15 ℃ or brine at-35 ℃ during secondary condensation.
4. The high-purity trifluoromethane purification method according to claim 1, wherein in the third step, difluoromethane and trifluoromethane are separated by a difluoromethane recovery tower (7), the pressure of the difluoromethane recovery tower (7) is controlled to be 1.5-1.8 MPa, the temperature of the top of the difluoromethane recovery tower (7) is controlled to be minus 15-10 ℃, the temperature of the bottom of the difluoromethane recovery tower (7) is controlled to be 20-30 ℃, the reflux ratio of the difluoromethane recovery tower (7) is controlled to be 50-100, a refrigerant in the difluoromethane recovery tower (7) adopts brine at minus 35 ℃, and the bottom of the difluoromethane recovery tower (7) is heated by steam or hot water.
5. The high-purity trifluoromethane purification method according to claim 1, wherein in the fourth step, the pressure of a trifluoromethane recovery tower (8) is controlled to be 1.2-1.5 MPa, the temperature of the top of the trifluoromethane recovery tower (8) is controlled to be minus 25-minus 15 ℃, the temperature of the tower bottom of the trifluoromethane recovery tower (8) is controlled to be minus 20-minus 10 ℃, the purity of a high-purity trifluoromethane finished product reaches 99.9%, the carbon dioxide content in the high-purity trifluoromethane finished product is less than or equal to 50ppm, the water content is less than or equal to 10ppm, the acidity is less than or equal to 0.1ppm, the refrigerant of a trifluoromethane condenser (9) is selected to be minus 35 ℃ saline, the refrigerant of the trifluoromethane recovery tower (8) is selected to be minus 35 ℃ saline, and the tower bottom of the trifluoromethane recovery tower (8) is selected to be +3℃.
6. A high purification device for trifluoromethane is characterized by mainly comprising a light component removal tower (1), a water alkali washing tower (2), a trifluoromethane buffer tank (3), a compressor (4), a pre-condenser (5), a trifluoromethane intermediate tank (6), a material conveying pump (23), a difluoromethane recovery tower (7), a trifluoromethane recovery tower (8), a trifluoromethane condenser (9) and a trifluoromethane finished product storage tank (10), wherein a reaction tower (11) for preparing difluoromethane is communicated with the side inlet of the light component removal tower (1) through a gas conveying pipeline (12), the top outlet of the light component removal tower (1) is communicated with the inlet of the water alkali washing tower (2), the outlet of the water alkali washing tower (2) is communicated with the side inlet of the trifluoromethane buffer tank (3), the bottom outlet of the trifluoromethane buffer tank (3) is communicated with the inlet at one side of the trifluoromethane intermediate tank (6) through the compressor (4) and the pre-condenser (5), the outlet at one side of the trifluoromethane intermediate tank (6) is communicated with the side inlet of the difluoromethane recovery tower (7) through the material conveying pump (23), the top outlet of the trifluoromethane recycling tower (8) is communicated with a trifluoromethane finished product storage tank (10) through a trifluoromethane condenser (9).
7. The high purification device of the trifluoromethane according to claim 6, wherein the light component removing tower (1) is a packed tower, the packing I (22) in the packed tower is stainless steel pall ring packing, stainless steel saddle ring packing or regular silk screen packing, and the water alkali washing tower (2) adopts steel lining equipment, and lining materials of the steel lining equipment are propylene oxide, polyethylene or polytetrafluoroethylene; the water wash column can also be a tray column.
8. The high purification device of trifluoromethane according to claim 6, wherein a material cut-off valve (13) is arranged on a feed pipeline of the trifluoromethane buffer tank (3), a buffer safety valve (14) is arranged in the trifluoromethane buffer tank (3), a pressure transmitter I (15) is arranged at the top of the trifluoromethane buffer tank (3), the pressure transmitter (15) is used for monitoring the pressure of the buffer tank, a pressure regulating valve (16) is arranged between an outlet at the bottom of the trifluoromethane buffer tank (3) and an inlet of the compressor (4), a pressure transmitter II (17) and a temperature transmitter I (18) are sequentially arranged on a pipeline at the outlet of the compressor (4), jackets (19) are arranged outside the trifluoromethane buffer tank (3), the trifluoromethane intermediate tank (6) and a trifluoromethane finished product storage tank (10), and a temperature transmitter II (20) is arranged on the jackets (19).
9. The high purification device of the trifluoromethane according to claim 6, wherein the difluoromethane recovery tower (11) and the trifluoromethane recovery tower (8) are packed towers, and the packing II (21) of the packed towers is stainless steel pall ring packing, stainless steel saddle ring packing or regular silk screen packing.
10. The high purification device of trifluoromethane according to claim 6, wherein the pre-condenser (5) and the trifluoromethane condenser (9) are shell-and-tube coolers or high-efficiency spiral heat exchangers.
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