CN113735683B - Purification device and purification method of electronic grade difluoromethane - Google Patents
Purification device and purification method of electronic grade difluoromethane Download PDFInfo
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- CN113735683B CN113735683B CN202111132681.3A CN202111132681A CN113735683B CN 113735683 B CN113735683 B CN 113735683B CN 202111132681 A CN202111132681 A CN 202111132681A CN 113735683 B CN113735683 B CN 113735683B
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Abstract
The invention discloses a purifying device of electronic grade difluoromethane, which comprises a pre-reactor and a secondary rectifying system connected with the pre-reactor, wherein the pre-reactor is a bubbling reactor, and the secondary rectifying system comprises a light component removing tower and a heavy component removing tower which are sequentially connected; the invention also discloses a method for purifying electronic grade difluoromethane by using the device, which comprises the following steps: and (3) respectively introducing the crude difluoromethane raw material and methanol-zinc powder slurry into inlet pipelines at the lower end and the upper end of a bubbling reactor, removing impurities such as hydrogen fluoride, water, difluoro chloromethane, difluoro dichloromethane and the like, and then carrying out secondary rectification through a light component removal tower and a heavy component removal tower to respectively remove light component impurities and heavy component impurities, thereby finally obtaining the electronic grade difluoromethane with the purity of more than 99.998 weight percent. The invention is treated by the bubbling reactor, which can effectively reduce the impurities which are difficult to remove by the rectification method, reduce the rectification difficulty and reduce the number of tower plates and the reflux ratio.
Description
Technical Field
The invention belongs to the technical field of electronic gas, and particularly relates to a purifying device and a purifying method of electronic grade difluoromethane.
Background
Difluoromethane of formula CH 2 F 2 Is nontoxic, nonflammable, easily soluble in oil and hardly soluble in water, and is a coolant with zero ozone depletion potential. Another main application of difluoromethane is in the manufacture of semiconductor and electronic productsCan be used as a source of etching CF free radicals in the process of radio frequency plasma treatment and as an etchant. Therefore, the demand of electronic grade difluoromethane is increasing, which is the guarantee of manufacturing high-level and high-quality semiconductor products, and the purity requirement of the products is more than or equal to 99.998 percent.
The synthesis method of difluoromethane mainly comprises the following four steps: a hydrochlorofluorocarbon catalytic hydrogenation process, a dichloromethane chlorofluorocarbon exchange process, a formaldehyde fluorination process and a trioxane process, wherein the chlorofluorocarbon exchange process is dominant. The reaction equation is:
CH 2 Cl 2 +HF＝CH 2 ClF+HCl
CH 2 ClF+HF＝CH 2 F 2 +HCl
2CH 2 ClF＝CH 2 F 2 +CH 2 Cl 2
in the process of synthesizing difluoromethane by adopting a difluoromethane fluorination method, a large amount of impurities can be generated. The organic silicon dioxide is mainly prepared from inorganic impurities such as nitrogen, oxygen, carbon dioxide, carbon monoxide, moisture, hydrogen fluoride and the like, and fluorocarbon compounds such as methylene dichloride, monofluoromethane, dichlorodifluoromethane and the like can be generated. According to the statistics of the United states department of commerce, the imported quantities of R32 from China in the United states are 1.11 ten thousand tons, 3.25 ten thousand tons and 4.02 ten thousand tons respectively, which are sufficient to indicate that the productivity of difluoromethane in China is large, so that the preparation of high-purity difluoromethane only considers the purification and separation technology.
The traditional method for obtaining high-purity difluoromethane gas by adopting two packed towers for continuous rectification is difficult to reach the purity requirement of 99.998 percent, and mainly has the following problems: (1) The difluoro methylene dichloride and the difluoro methane form azeotropes and are used as a lost product when light components are removed; (2) Impurity water enters a low-temperature rectification system to be solidified, so that the operation of equipment is not facilitated, and the safety problem is easily caused; (3) impurity hydrogen fluoride is acid gas, and equipment is easy to corrode. Therefore, it is important to develop a purification method and a purification device for electronic grade difluoromethane.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a purifying device and a purifying method for electronic grade difluoromethane aiming at the defects of the prior art. The method comprises the steps of removing impurities such as hydrogen fluoride, water, difluoro chloromethane, difluoro dichloromethane and the like in a bubbling reactor, and respectively removing light components and heavy components through a light component removal tower and a heavy component removal tower to finally obtain the electronic grade difluoro methane with the purity of more than 99.998 weight percent.
In order to solve the technical problems, the invention adopts the following technical scheme: the utility model provides a purification device of electronic grade difluoromethane, its characterized in that, include the prereactor and with the secondary rectification system that the prereactor is connected, the prereactor is the bubble reactor, the secondary rectification system is including the light component removal tower and the heavy component removal tower that connect gradually, bubble reactor upper end export is provided with condenser one, condenser one and light component removal tower import pipeline connection, the top of light component removal tower is provided with condenser two, and the tower cauldron is provided with reboiler one, the top of heavy component removal tower is provided with condenser three, and the tower cauldron is provided with reboiler two, reboiler one with heavy component removal tower import pipeline connection.
Preferably, the first condenser is provided with a reflux pipeline connected with the top of the bubbling reactor, the second condenser is provided with a reflux pipeline connected with the top of the light-removal tower, and the third condenser is provided with a reflux pipeline connected with the top of the heavy-removal tower.
The invention also provides a method for purifying electronic grade trifluoromethane by using the device, which is characterized by comprising the following steps:
s1, introducing a crude difluoromethane raw material stream into an inlet pipeline at the lower end of a bubbling reactor, introducing a methanol-zinc powder slurry stream into an inlet pipeline at the upper end of the bubbling reactor, performing pretreatment reaction, discharging a waste material stream from an outlet at the bottom of the bubbling reactor after the reaction, condensing and refluxing part of methanol by an outlet material at the upper end of the bubbling reactor, and gas-phase extracting a mixed gas stream; the operation temperature of the bubbling reactor is 80-110 ℃, and the operation pressure is 0.3-1.0 MPa;
s2, introducing the mixed gas flow in the S1 into a light component removal tower for primary rectification after passing through a condenser I, wherein the operating temperature of the light component removal tower is-36-7 ℃, the operating pressure of the light component removal tower is 2-10 bar, the top of the light component removal tower is used for producing a light component flow through a condenser II gas phase, and the bottom of the light component removal tower is used for producing a flow comprising difluoromethane, chloromethane, methanol and water through a reboiler I;
and S3, introducing the material flow comprising difluoromethane, chloromethane, methanol and water into an inlet pipeline of a heavy removal tower through a first reboiler, performing secondary rectification in the heavy removal tower to remove heavy components, wherein the operating temperature of the heavy removal tower is-37-0 ℃, the operating pressure of the heavy removal tower is 2-10 bar, the top of the heavy removal tower is used for extracting electronic grade difluoromethane through a third gas phase of the condenser, and the tower bottom is used for extracting heavy component material flow through the second reboiler.
Preferably, the mass ratio of the crude difluoromethane feed stream to the methanol-zinc powder slurry stream in S1 is 2-5, the methanol-zinc powder slurry stream comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry stream is 5-15.
Preferably, the gas phase produced mixed gas stream in S1 comprises difluoromethane, hydrogen fluoride, difluoromethane chloride, difluoromethane, water and methanol, and the reject stream comprises zinc chloride and zinc hydroxide.
Preferably, the light component stream in S2 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride; the heavy component stream in S3 comprises methyl chloride, methanol and water.
Preferably, the theoretical plate number of the light component removing tower in the S2 is 40-60, and the reflux ratio is 100-200.
Preferably, the theoretical plate number of the weight removing tower in the step S3 is 60-80, and the reflux ratio is 3-8.
The reaction principle in the bubbling reactor in S1 is as follows:
(1) Methanol reacts with hydrogen fluoride as follows:
CH 3 OH+HF＝CH 3 F+H 2 O
converting hydrogen fluoride into monofluoromethane which is easy to separate in a subsequent rectification process, and preventing acid gas from entering a subsequent rectification separation system;
(2) Zinc powder is subjected to reduction dechlorination to remove chlorodifluoromethane with a boiling point close to that of difluoromethane, and the reaction is as follows:
2CHClF 2 +2Zn+2H 2 O＝2CH 2 F 2 +ZnCl 2 +Zn(OH) 2
CCl 2 F 2 +2Zn+2H 2 O＝CH 2 F 2 +ZnCl 2 +Zn(OH) 2
converting difluoromethane forming an azeotrope with difluoromethane into a difluoromethane product by means of zinc dust dechlorination; meanwhile, the difluoromethane chloride is converted into a difluoromethane product, so that the separation difficulty in the subsequent rectification process is reduced; methanol is complexed with zinc chloride generated by the reaction, separated from the zinc surface, and zinc in the zinc surface is exposed, so that the reduction dechlorination can be continued.
The mixed gas flow obtained after the pretreatment reaction is easier to remove other impurity components in the subsequent rectification process, and simultaneously, the optimal reaction conditions such as the temperature, the number of tower plates, the pressure and the like of the light component removal tower and the heavy component removal tower in the subsequent rectification process are determined.
Compared with the prior art, the invention has the following advantages:
1. according to the invention, impurities such as hydrogen fluoride, water, difluoro chloromethane, difluoro dichloromethane and the like are removed by adopting the bubbling reactor, and the methyl alcohol converts the hydrogen fluoride into the monofluoromethane which is easy to separate in the subsequent rectification process, so that the acidic gas is prevented from entering a subsequent rectification separation system; converting difluoromethane forming an azeotrope with difluoromethane into a difluoromethane product by means of zinc dust dechlorination; meanwhile, the difluoromethane chloride is converted into a difluoromethane product, so that the separation difficulty in the subsequent rectification process is reduced; methanol is complexed with zinc chloride generated by the reaction, separated from the zinc surface, and zinc in the zinc surface is exposed, so that the reduction dechlorination can be continued.
2. The bubbling reactor is adopted, so that impurities which are difficult to separate are removed firstly, and then the light component and heavy component impurities are removed by the rectification system, so that the technology is stable, and the cost is low; the bubbling reactor absorbs trace water and hydrogen fluoride, and plays a role in extraction and rectification of the water and the hydrogen fluoride in a rectification system.
3. According to the invention, methanol is introduced into the raw materials through the bubbling reactor, so that the freezing point of water is reduced, the water is prevented from being solidified in the low-temperature light component removal tower, low-temperature rectification dehydration is realized, and an additional adsorption dehydration process is avoided.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a schematic diagram of the structure of the purification apparatus of the present invention.
Reference numerals illustrate:
1-a crude difluoromethane feed stream; 2-methanol-zinc powder slurry stream; 3-a waste stream; 4-a mixed gas stream; 5-a lights stream; 6-a stream comprising difluoromethane, chloromethane, methanol and water; 7-an electronic grade difluoromethane product stream; 8—a heavy component stream; r101 is a bubbling reactor; t101-a light component removing tower; t102-a heavy-duty removal tower; e101-condenser one; e102, a second condenser; e103-reboiler one; e104—condenser three; e105—reboiler two.
Detailed Description
Example 1
The purification device of electronic grade difluoromethane in this embodiment, include the prereactor and with the secondary rectification system that prereactor is connected, the prereactor is bubbling reactor R101, secondary rectification system is including the light component removal tower T101 and the heavy component removal tower T102 that connect gradually, bubbling reactor R101 upper end export is provided with condenser one E101, condenser one E101 is connected with light component removal tower T101 import pipeline, light component removal tower T101's top of tower is provided with condenser two E102, and the tower cauldron is provided with reboiler one E103, heavy component removal tower T102's top of tower is provided with condenser three E104, and the tower cauldron is provided with reboiler two E105, reboiler one E103 with heavy component removal tower T102 import pipeline connection. And a reflux pipeline is arranged on the first condenser E101 and connected with the top of the bubbling reactor R101, a reflux pipeline is arranged on the second condenser E102 and connected with the top of the light component removal tower T101, and a reflux pipeline is arranged on the third condenser E104 and connected with the top of the heavy component removal tower T102.
Example 2
The crude difluoromethane feed stream 1 used in this example was of the specification (mass percent): crude difluoromethane of purity 98.60% with impurities including 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% chloromethane, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluoromethane and 0.1% water.
The method for purifying electronic grade trifluoromethane by using the device of the embodiment 1 comprises the following steps:
s1, introducing a crude difluoromethane raw material stream 1 into a lower inlet pipeline of a bubbling reactor R101, introducing a methanol-zinc powder slurry stream 2 into an upper inlet pipeline, performing pretreatment reaction, discharging a waste material stream 3 from an outlet at the bottom of the bubbling reactor R101 after the reaction, condensing and refluxing part of methanol by an upper outlet material stream through a condenser E101, and gas-phase extracting a mixed gas stream 4; the operating temperature of the bubbling reactor R101 is 90 ℃ and the operating pressure is 0.3MPa; the mass flow rate of the crude difluoromethane feed stream 1 to the bubbling reactor R101 is 100kg/hr, the mass flow rate of the methanol-zinc powder slurry stream 2 is 44kg/hr, and the mass ratio of the crude difluoromethane feed stream 1 to the methanol-zinc powder slurry stream 2 is 1:3, the methanol-zinc powder slurry stream 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry stream 2 is 1:10;
the purity of difluoromethane in the mixed gas stream 4 is 98.99wt%, the content of hydrogen fluoride is 0.1ppm, the content of difluoromethane chloride is less than 0.1ppm, the content of difluoromethane is less than 0.1ppm, the content of water is 0.15%, the content of methanol is 0.4%, the content of gas impurities is reduced to below 0.1ppm after passing through the bubbling reactor R101 to meet the requirement of the final product, and the content of methanol and water is increased; waste stream 3 comprises zinc chloride and zinc hydroxide;
s2, introducing the mixed gas stream 4 in S1 into a light component removal tower T101 for primary rectification after passing through a condenser I E101, wherein the operation temperature of the light component removal tower T101 is minus 37 ℃, the operation pressure is 2bar, the theoretical plate number is 40, the position of an inlet pipeline of the light component removal tower is at a 20 th plate, the reflux rate is 200kg/h, the reflux ratio is 100, the light component stream 5 is obtained from the tower top of the light component removal tower T101 through a condenser II E102 in a gas phase, and the stream 6 comprising difluoromethane, chloromethane, methanol and water is obtained from the tower bottom through a reboiler I E103; light component stream 5 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;
s3, introducing the material flow 6 comprising difluoromethane, chloromethane, methanol and water into an inlet pipeline of a heavy removal tower T102 through a reboiler E103, performing secondary rectification in the heavy removal tower T102 to remove heavy components, wherein the operating temperature of the heavy removal tower T102 is minus 33 ℃, the operating pressure is 2bar, the theoretical plate number is 60, the position of the inlet pipeline of the heavy removal tower is at a 20 th plate, the reflux ratio is 3, the top of the heavy removal tower T102 is subjected to gas phase extraction of an electronic grade difluoromethane product material flow 7 through a condenser E104, and the tower bottom is subjected to gas phase extraction of a heavy component material flow 8 through a reboiler E105; stream 6 comprising difluoromethane, chloromethane, methanol and water has a mass flow rate of 98kg/hr, wherein the difluoromethane purity is 99.27% by weight; heavy component stream 8 comprises methyl chloride, methanol, and water;
and (3) detecting: the mass flow rate of the electronic grade difluoromethane 7 is 94kg/hr, the purity is more than 99.998wt%, the nitrogen content is less than 8ppm, the oxygen content is less than 2ppm, the water content is less than 5ppm, the hydrogen fluoride content is less than 0.1ppm, the carbon dioxide content is less than 5ppm, the other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20ppm.
Example 3
The crude difluoromethane feed stream 1 used in this example was of the specification (mass percent): crude difluoromethane of purity 98.60% with impurities including 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% chloromethane, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluoromethane and 0.1% water.
The method for purifying electronic grade trifluoromethane by using the device of the embodiment 1 comprises the following steps:
s1, introducing a crude difluoromethane raw material stream 1 into a lower inlet pipeline of a bubbling reactor R101, introducing a methanol-zinc powder slurry stream 2 into an upper inlet pipeline, performing pretreatment reaction, discharging a waste material stream 3 from an outlet at the bottom of the bubbling reactor R101 after the reaction, condensing and refluxing part of methanol by an upper outlet material stream through a condenser E101, and gas-phase extracting a mixed gas stream 4; the operating temperature of the bubbling reactor R101 is 100 ℃ and the operating pressure is 0.6MPa; the mass flow rate of the crude difluoromethane feed stream 1 to the bubbling reactor R101 is 100kg/hr, the mass flow rate of the methanol-zinc powder slurry stream 2 is 48kg/hr, and the mass ratio of the crude difluoromethane feed stream 1 to the methanol-zinc powder slurry stream 2 is 1:5, the methanol-zinc powder slurry stream 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry stream 2 is 1:15;
the purity of difluoromethane in the mixed gas stream 4 is 98.59wt%, the content of hydrogen fluoride is lower than 0.1ppm, the content of difluoromethane chloride is lower than 0.1ppm, the content of difluoromethane is lower than 0.1ppm, the content of water is 0.2%, and the content of methanol is 0.4%; waste stream 3 comprises zinc chloride and zinc hydroxide;
s2, introducing the mixed gas stream 4 in S1 into a light component removal tower T101 for primary rectification after passing through a condenser I E101, wherein the operation temperature of the light component removal tower T101 is minus 19 ℃, the operation pressure is 5bar, the theoretical plate number is 50, the reflux ratio is 150, the light component stream 5 is obtained from the tower top of the light component removal tower T101 through a condenser II E102 in a gas phase, and the stream 6 comprising difluoromethane, chloromethane, methanol and water is obtained from the tower bottom through a reboiler I E103; light component stream 5 treasury nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;
s3, introducing a stream 6 comprising difluoromethane, chloromethane, methanol and water into an inlet pipeline of a heavy removal tower T102 through a reboiler E103, performing secondary rectification in the heavy removal tower T102 to remove heavy components, wherein the operating temperature of the heavy removal tower T102 is minus 9 ℃, the operating pressure is 5bar, the theoretical plate number is 70, the reflux ratio is 5, the top of the heavy removal tower T102 is subjected to gas phase extraction of an electronic grade difluoromethane product stream 7 through a condenser E104, and the bottom of the tower is subjected to gas phase extraction of a heavy component stream 8 through a reboiler E105; stream 6 comprising difluoromethane, chloromethane, methanol and water has a mass flow rate of 97kg/hr, wherein the difluoromethane purity is 99.08% by weight; heavy component stream 8 comprises methyl chloride, methanol, and water;
and (3) detecting: the mass flow rate of the electronic grade difluoromethane product stream 7 is 94kg/hr, the purity is more than 99.998wt%, the nitrogen content is less than 8ppm, the oxygen content is less than 2ppm, the water content is less than 5ppm, the hydrogen fluoride content is less than 0.1ppm, the carbon dioxide content is less than 5ppm, the other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20ppm.
Example 4
The crude difluoromethane feed stream 1 used in this example was of the specification (mass percent): crude difluoromethane of purity 98.60% with impurities including 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% chloromethane, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluoromethane and 0.1% water.
The method for purifying electronic grade trifluoromethane by using the device of the embodiment 1 comprises the following steps:
s1, introducing a crude difluoromethane raw material stream 1 into a lower inlet pipeline of a bubbling reactor R101, introducing a methanol-zinc powder slurry stream 2 into an upper inlet pipeline, performing pretreatment reaction, discharging a waste material stream 3 from an outlet at the bottom of the bubbling reactor R101 after the reaction, condensing and refluxing part of methanol by an upper outlet material stream through a condenser E101, and gas-phase extracting a mixed gas stream 4; the operating temperature of the bubbling reactor R101 is 105 ℃ and the operating pressure is 1.0MPa; the mass flow rate of the crude difluoromethane feed stream 1 to the bubbling reactor R101 is 100kg/hr, the mass flow rate of the methanol-zinc powder slurry stream 2 is 48kg/hr, and the mass ratio of the crude difluoromethane feed stream 1 to the methanol-zinc powder slurry stream 2 is 1:2, the methanol-zinc powder slurry stream 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry stream 2 is 1:5;
the purity of difluoromethane in the mixed gas stream 4 is 98.99wt%, the content of hydrogen fluoride is lower than 0.1ppm, the content of difluoromethane chloride is lower than 0.1ppm, the content of difluoromethane is lower than 0.1ppm, the water content is 0.4%, and the content of methanol is 0.4%; waste stream 3 comprises zinc chloride and zinc hydroxide;
s2, introducing the mixed gas stream 4 in S1 into a light component removal tower T101 for primary rectification after passing through a condenser I E101, wherein the operation temperature of the light component removal tower T101 is-0.4 ℃, the operation pressure is 8bar, the theoretical plate number is 60, the reflux ratio is 200, the light component stream 5 is obtained from the tower top of the light component removal tower T101 through a condenser II E102 in a gas phase mode, and the stream 6 comprising difluoromethane, chloromethane, methanol and water is obtained from the tower bottom through a reboiler I E103; light component stream 5 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;
s3, introducing a stream 6 containing difluoromethane, chloromethane, methanol and water in S2 into an inlet pipeline of a heavy component removal tower T102 through a reboiler E103, performing secondary rectification in the heavy component removal tower T102, wherein the operating temperature of the heavy component removal tower T102 is-10 ℃, the operating pressure is 6bar, the theoretical plate number is 80, the reflux ratio is 6, the top of the heavy component removal tower T102 is subjected to gas phase extraction of an electronic grade difluoromethane product stream 7 through a condenser E104, and the tower bottom is subjected to gas phase extraction of a heavy component stream 8 through a reboiler E105; stream 6 comprising difluoromethane, chloromethane, methanol and water has a mass flow rate of 97kg/hr, wherein the difluoromethane purity is 99.08% by weight; heavy component stream 8 comprises methyl chloride, methanol, and water;
and (3) detecting: the mass flow rate of the electronic grade difluoromethane product stream 7 is 94kg/hr, the purity is more than 99.998wt%, the nitrogen content is less than 8ppm, the oxygen content is less than 2ppm, the water content is less than 5ppm, the hydrogen fluoride content is less than 0.1ppm, the carbon dioxide content is less than 5ppm, the other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20ppm.
Example 5
The crude difluoromethane feed stream 1 used in this example was of the specification (mass percent): crude difluoromethane of purity 98.60% with impurities including 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% chloromethane, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluoromethane and 0.1% water.
The method for purifying electronic grade trifluoromethane by using the device of the embodiment 1 comprises the following steps:
s1, introducing a crude difluoromethane raw material stream 1 into a lower inlet pipeline of a bubbling reactor R101, introducing a methanol-zinc powder slurry stream 2 into an upper inlet pipeline, performing pretreatment reaction, discharging a waste material stream 3 from an outlet at the bottom of the bubbling reactor R101 after the reaction, condensing and refluxing part of methanol by an upper outlet material stream through a condenser E101, and gas-phase extracting a mixed gas stream 4; the operating temperature of the bubbling reactor R101 is 110 ℃, and the operating pressure is 1.0MPa; the mass flow rate of the crude difluoromethane feed stream 1 to the bubbling reactor R101 is 100kg/hr, the mass flow rate of the methanol-zinc powder slurry stream 2 is 48kg/hr, and the mass ratio of the crude difluoromethane feed stream 1 to the methanol-zinc powder slurry stream 2 is 1:4, the methanol-zinc powder slurry stream 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry stream 2 is 1:13;
the purity of difluoromethane in the mixed gas stream 4 is 98.99wt%, the content of hydrogen fluoride is lower than 0.1ppm, the content of difluoromethane chloride is lower than 0.1ppm, the content of difluoromethane is lower than 0.1ppm, the water content is 0.4%, and the content of methanol is 0.4%; waste stream 3 comprises zinc chloride and zinc hydroxide;
s2, introducing the mixed gas stream 4 in S1 into a light component removal tower T101 for primary rectification after passing through a condenser I E101, wherein the operation temperature of the light component removal tower T101 is 7 ℃, the operation pressure is 10bar, the theoretical plate number is 60, the reflux ratio is 200, the light component stream 5 is obtained from the tower top of the light component removal tower T101 through a condenser II E102 in a gas phase, and the stream 6 comprising difluoromethane, chloromethane, methanol and water is obtained from the tower bottom through a reboiler I E103; light component stream 5 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;
s3, introducing a stream 6 comprising difluoromethane, chloromethane, methanol and water into an inlet pipeline of a heavy removal tower T102 through a reboiler E103, performing secondary rectification in the heavy removal tower T102 to remove heavy components, wherein the operating temperature of the heavy removal tower T102 is 0 ℃, the operating pressure is 10bar, the theoretical plate number is 80, the reflux ratio is 8, the top of the heavy removal tower T102 is subjected to gas phase extraction of an electronic grade difluoromethane product stream 7 through a condenser E104, and the bottom of the tower is subjected to gas phase extraction of a heavy component stream 8 through a reboiler E105; stream 6 comprising difluoromethane, chloromethane, methanol and water has a mass flow rate of 97kg/hr, wherein the difluoromethane purity is 99.08% by weight; heavy component stream 8 comprises methyl chloride, methanol, and water;
and (3) detecting: the mass flow rate of the electronic grade difluoromethane product stream 7 is 94kg/hr, the purity is more than 99.998wt%, the nitrogen content is less than 8ppm, the oxygen content is less than 2ppm, the water content is less than 5ppm, the hydrogen fluoride content is less than 0.1ppm, the carbon dioxide content is less than 5ppm, the other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20ppm.
The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention. Any simple modification, variation and equivalent variation of the above embodiments according to the technical substance of the invention still fall within the scope of the technical solution of the invention.
Claims (8)
1. The purifying device for the electronic grade difluoromethane is characterized by comprising a pre-reactor and a secondary rectifying system connected with the pre-reactor, wherein the pre-reactor is a bubbling reactor (R101), the secondary rectifying system comprises a light component removing tower (T101) and a heavy component removing tower (T102) which are sequentially connected, a condenser I (E101) is arranged at an outlet at the upper end of the bubbling reactor (R101), the condenser I (E101) is connected with an inlet pipeline of the light component removing tower (T101), a condenser II (E102) is arranged at the top of the light component removing tower (T101), a reboiler I (E103) is arranged at the tower bottom, a condenser III (E104) is arranged at the top of the heavy component removing tower (T102), a reboiler II (E105) is arranged at the tower bottom, and the reboiler I (E103) is connected with the inlet pipeline of the heavy component removing tower (T102);
the lower inlet pipeline of the bubbling reactor (R101) is filled with a crude difluoromethane raw material stream (1), the upper inlet pipeline is filled with a methanol-zinc powder slurry stream (2), pretreatment reaction is carried out, and methanol converts hydrogen fluoride into monofluoromethane which is easy to separate in the subsequent rectification process; the zinc powder is subjected to reduction dechlorination reaction, so that the difluoro methylene dichloride which forms an azeotrope with the difluoro methane is converted into a difluoro methane product, and the difluoro chloromethane is converted into the difluoro methane product, and the separation difficulty in the subsequent rectification process is reduced; the methanol is complexed with zinc chloride generated by the reductive dechlorination reaction, is separated from the surface of zinc, exposes zinc in the interior, and can continue reductive dechlorination.
2. The purification device of electronic grade difluoromethane according to claim 1, wherein a reflux pipeline is arranged on the first condenser (E101) and connected with the top of the bubbling reactor (R101), a reflux pipeline is arranged on the second condenser (E102) and connected with the top of the light component removal tower (T101), and a reflux pipeline is arranged on the third condenser (E104) and connected with the top of the heavy component removal tower (T102).
3. A method of purifying difluoromethane using the apparatus of claim 1 or 2, comprising the steps of:
s1, introducing a crude difluoromethane raw material stream into an inlet pipeline at the lower end of a bubbling reactor, introducing a methanol-zinc powder slurry stream into an inlet pipeline at the upper end of the bubbling reactor, performing pretreatment reaction, discharging a waste material stream from an outlet at the bottom of the bubbling reactor after the reaction, condensing and refluxing part of methanol by an outlet material at the upper end of the bubbling reactor, and gas-phase extracting a mixed gas stream; the operation temperature of the bubbling reactor is 80-110 ℃, and the operation pressure is 0.3-1.0 MPa; the crude difluoromethane feed stream comprises difluoromethane, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, hydrogen fluoride, chloromethane, trifluoromethane, ethane, carbon tetrafluoride, difluoromethane and water; the mixed gas stream comprises difluoromethane, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, chloromethane, trifluoromethane, ethane, carbon tetrafluoride, water and methanol;
s2, introducing the mixed gas flow into a light component removal tower to carry out primary rectification after passing through a first condenser, wherein the operating temperature of the light component removal tower is-36-7 ℃, the operating pressure of the light component removal tower is 2b ar-10 bar, the top of the light component removal tower is subjected to gas phase extraction through a second condenser, and the bottom of the light component removal tower is subjected to gas phase extraction through a first reboiler to obtain a material flow comprising difluoromethane, chloromethane, methanol and water;
and S3, introducing the material flow comprising difluoromethane, chloromethane, methanol and water into an inlet pipeline of a heavy removal tower through a first reboiler, performing secondary rectification in the heavy removal tower to remove heavy components, wherein the operating temperature of the heavy removal tower is-37-0 ℃, the operating pressure of the heavy removal tower is 2b ar-10 bar, the top of the heavy removal tower is used for extracting electronic grade difluoromethane through a third gas phase of the condenser, and the bottom of the heavy removal tower is used for extracting heavy component material flow through the second reboiler.
4. A process for purifying difluoromethane according to claim 3, wherein the mass ratio of said crude difluoromethane feed stream and methanol-zinc powder slurry stream in S1 is 1: (2-5), wherein the methanol-zinc powder slurry stream comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry stream is 1: (5-15).
5. A method of purifying difluoromethane according to claim 3, wherein said waste stream in S1 comprises zinc chloride and zinc hydroxide.
6. A method of purifying difluoromethane according to claim 3, wherein said light component stream in S2 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride; the heavy component stream in S3 comprises methyl chloride, methanol and water.
7. The method for purifying difluoromethane according to claim 3, wherein the theoretical plate number of the light component removal column in S2 is 40 to 60, and the reflux ratio is 100 to 200.
8. The method for purifying difluoromethane according to claim 3, wherein the theoretical plate number of the de-weight column in S3 is 60 to 80, and the reflux ratio is 3 to 8.
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| CN115385772A (en) * | 2022-07-04 | 2022-11-25 | 中船(邯郸)派瑞特种气体股份有限公司 | Purification method of electronic-grade monofluoromethane |
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