阅读说明：本技术 一种电子级二氟甲烷的纯化装置及其纯化方法 (Purification device and purification method for electronic-grade difluoromethane ) 是由 张建伟 张琴 倪珊珊 郑旭阳 鲁毅 张帅 姜世楠 于 2021-09-27 设计创作，主要内容包括：本发明公开了一种电子级二氟甲烷的纯化装置,该装置包括预反应器和与所述预反应器连接的二级精馏系统,所述预反应器为鼓泡反应器,所述二级精馏系统包括依次连接的脱轻塔和脱重塔；本发明还公开一种使用上述装置纯化电子级二氟甲烷的方法为：将粗品二氟甲烷原料和甲醇-锌粉浆料分别通入鼓泡反应器的下端和上端进口管道,脱除氟化氢、水、二氟一氯甲烷和二氟二氯甲烷等杂质后,再通过脱轻塔和脱重塔进行二级精馏,分别脱除轻组分杂质和重组分杂质,最终得到纯度大于99.998wt％的电子级二氟甲烷。本发明先经鼓泡反应器处理,可有效降低用精馏方法难以脱除的杂质,降低精馏的难度,使塔板数和回流比降低。(The invention discloses a purification device of electronic-grade difluoromethane, which comprises a pre-reactor and a secondary rectification system connected with the pre-reactor, wherein the pre-reactor is a bubble reactor, and the secondary rectification system comprises a light component removal tower and a heavy component removal tower which are sequentially connected; the invention also discloses a method for purifying the electronic-grade difluoromethane by using the device, which comprises the following steps: and (3) respectively introducing the crude difluoromethane raw material and the methanol-zinc powder slurry into inlet pipelines at the lower end and the upper end of the bubbling reactor, removing impurities such as hydrogen fluoride, water, difluorochloromethane, difluorodichloromethane and the like, and then performing secondary rectification by a light component removing tower and a heavy component removing 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 wt%. The invention is treated by the bubbling reactor, which can effectively reduce the impurities which are difficult to be removed by the rectification method, reduce the difficulty of rectification and reduce the number of tower plates and reflux ratio.)

1. The utility model provides a purification device of electron level difluoromethane, characterized in that, including the prereactor with the second grade rectification system that the prereactor is connected, the prereactor is bubbling reactor (R101), second grade rectification system is including lightness-removing tower (T101) and heavy-duty tower (T102) that connect gradually, bubbling reactor (R101) upper end export is provided with condenser (E101), condenser (E101) and lightness-removing tower (T101) inlet pipe connection, the top of the tower of lightness-removing tower (T101) is provided with condenser two (E102), and the tower cauldron is provided with reboiler (E103), the top of the tower of reboiler (T102) is provided with condenser three (E104), and the tower cauldron is provided with two (E105), one (E103) with heavy-duty tower (T102) inlet pipe connection takes off.

2. The purification device of electronic grade difluoromethane according to claim 1, wherein said first condenser (E101) is provided with a reflux pipeline connected to the top of said bubble reactor (R101), said second condenser (E102) is provided with a reflux pipeline connected to the top of said light component removal column (T101), and said third condenser (E104) is provided with a reflux pipeline connected to the top of said heavy component removal column (T102).

3. A method for purifying difluoromethane using the apparatus of any of claims 1-2, comprising the steps of:

s1, introducing a crude difluoromethane raw material flow into an inlet pipeline at the lower end of the bubbling reactor, introducing a methanol-zinc powder slurry flow into an inlet pipeline at the upper end of the bubbling reactor, carrying out pretreatment reaction, discharging a waste material flow from an outlet at the bottom of the bubbling reactor after reaction, and collecting a mixed gas flow in a gas phase after the upper end outlet flow is condensed and refluxed to part of methanol by a condenser I; the operating temperature of the bubbling reactor is 80-110 ℃, and the operating pressure is 0.3-1.0 MPa;

the mixed gas flows through the condenser I in S2 and S1 and then is fed into a light component removal tower for primary rectification to remove light components, the operating temperature of the light component removal tower is-36-7 ℃, the operating pressure is 2-10 bar, the light component flow is extracted from the top of the light component removal tower through the condenser II gas phase, and the flow comprising difluoromethane, monochloromethane, methanol and water is extracted from the tower kettle through the reboiler I;

and in S3 and S2, the material flow comprising difluoromethane, methane chloride, methanol and water is introduced into an inlet pipeline of a de-heavy tower through a reboiler I, secondary rectification is performed in the de-heavy tower to remove heavy components, the operating temperature of the de-heavy tower is-37-0 ℃, the operating pressure is 2-10 bar, electronic-grade difluoromethane is extracted from the top of the de-heavy tower through a condenser in a three-phase mode, and heavy component material flow is extracted from a tower kettle through the reboiler II.

4. The purification process of claim 3, wherein the mass ratio of the crude difluoromethane feed stream to the methanol-zinc dust slurry stream in S1 is 1: (2-5), the methanol-zinc powder slurry material flow comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry material flow is 1: (5-15).

5. The purification process according to claim 3, wherein the gas phase withdrawn mixed gas stream in S1 comprises difluoromethane, hydrogen fluoride, difluoromethane chloride, difluorodichloromethane, water and methanol, and the waste stream comprises zinc chloride and zinc hydroxide.

6. The purification process of claim 3, wherein the lights stream in S2 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane, and carbon tetrafluoride; the heavies stream in S3 includes methyl chloride, methanol, and water.

7. The purification process according to claim 3, wherein the number of theoretical plates of the light ends removal column in S2 is 40 to 60, and the reflux ratio is 100 to 200.

8. The purification method according to claim 3, wherein the number of theoretical plates of the de-heaving column in S3 is 60 to 80, and the reflux ratio is 3 to 8.

Technical Field

The invention belongs to the technical field of electronic gas, and particularly relates to a purification device and a purification method for electronic-grade difluoromethane.

Background

Difluoromethane of the formula CH₂F₂It is non-toxic, non-flammable, easily soluble in oil and insoluble in water, and is a cooling agent with zero ozone depletion potential. Difluoromethane is also used as a source of etching CF radicals as an etchant in RF plasma processing in the manufacture of semiconductors and electronic products. Therefore, the demand of electronic grade difluoromethane is more and more, which is a guarantee for manufacturing high-level and high-quality semiconductor products, and the purity requirement of the products is more than or equal to 99.998%.

The synthesis method of difluoromethane mainly comprises the following four methods: hydrochlorofluorocarbon catalytic hydrogenation, dichloromethane chlorofluorination, formaldehyde fluorination and trioxane processes, with chlorofluorocarbon exchange predominating. The reaction equation is:

CH₂Cl₂+HF＝CH₂ClF+HCl

CH₂ClF+HF＝CH₂F₂+HCl

2CH₂ClF＝CH₂F₂+CH₂Cl₂

in the process of synthesizing difluoromethane by the difluoromethane fluorination method, a large amount of impurities are generated. It mainly contains inorganic impurities such as nitrogen, oxygen, carbon dioxide, carbon monoxide, water, hydrogen fluoride, etc., and also generates fluorocarbons such as dichloromethane, monochloromethane, dichlorodifluoromethane, etc. According to statistics of the United states department of commerce, 2016-2018, import quantities of R32 from China in the United states are respectively 1.11 ten thousand tons, 3.25 ten thousand tons and 4.02 ten thousand tons, which are enough for indicating that the capacity of difluoromethane in China is large, so that the preparation of high-purity difluoromethane only considers the purification and separation technology.

Traditionally, the method of continuously rectifying high-purity difluoromethane gas by adopting two packed towers is difficult to achieve the purity requirement of 99.998 percent, and mainly has the following problems: (1) difluoro dichloromethane and difluoromethane form azeotropy, as the loss product when the light component is removed; (2) impurity water entering a low-temperature rectification system can be solidified, so that equipment is not easy to operate, and safety problems are easily caused; (3) the impurity hydrogen fluoride is acid gas and is easy to corrode equipment. Therefore, it is important to develop a method and apparatus for purifying electronic grade difluoromethane.

Disclosure of Invention

The present invention provides a device and a method for purifying electronic-grade difluoromethane, which are directed to overcome the above-mentioned shortcomings in the prior art. The method comprises the steps of removing impurities such as hydrogen fluoride, water, difluorochloromethane, difluorodichloromethane and the like in a bubble reactor, and respectively removing light components and heavy components in a light component removing tower and a heavy component removing tower to finally obtain the electronic-grade difluoromethane with the purity of more than 99.998 wt%.

In order to solve the technical problems, the invention adopts the technical scheme that: the utility model provides a purification device of electron level difluoromethane, its characterized in that, including the prereactor and with the second grade rectification system that the prereactor is connected, the prereactor is the tympanic bulla reactor, second grade rectification system is including the lightness-removing tower that connects gradually and the heavy-duty tower that takes off, tympanic bulla reactor upper end export is provided with condenser one, condenser one with take off light tower inlet pipe connection, the top of the tower of lightness-removing tower is provided with condenser two, and the tower cauldron is provided with reboiler one, the top of the tower of heavy-duty tower is provided with condenser three, and the tower cauldron is provided with reboiler two, reboiler one with take off heavy-duty tower inlet pipe connection.

Preferably, a reflux pipeline is arranged on the first condenser and connected with the top of the bubble reactor, a reflux pipeline is arranged on the second condenser and connected with the top of the light component removal tower, and a reflux pipeline is arranged on the third condenser and connected with the top of the heavy component 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 of:

s1, introducing a crude difluoromethane raw material flow into an inlet pipeline at the lower end of the bubbling reactor, introducing a methanol-zinc powder slurry flow into an inlet pipeline at the upper end of the bubbling reactor, carrying out pretreatment reaction, discharging a waste material flow from an outlet at the bottom of the bubbling reactor after reaction, and collecting a mixed gas flow in a gas phase after the upper end outlet flow is condensed and refluxed to part of methanol by a condenser I; the operating temperature of the bubbling reactor is 80-110 ℃, and the operating pressure is 0.3-1.0 MPa;

the mixed gas flows through the condenser I in S2 and S1 and then is fed into a light component removal tower for primary rectification to remove light components, the operating temperature of the light component removal tower is-36-7 ℃, the operating pressure is 2-10 bar, the light component flow is extracted from the top of the light component removal tower through the condenser II gas phase, and the flow comprising difluoromethane, monochloromethane, methanol and water is extracted from the tower kettle through the reboiler I;

and in S3 and S2, the material flow comprising difluoromethane, methane chloride, methanol and water is introduced into an inlet pipeline of a de-heavy tower through a reboiler I, secondary rectification is performed in the de-heavy tower to remove heavy components, the operating temperature of the de-heavy tower is-37-0 ℃, the operating pressure is 2-10 bar, electronic-grade difluoromethane is extracted from the top of the de-heavy tower through a condenser in a three-phase mode, and heavy component material flow is extracted from a tower kettle through the reboiler II.

Preferably, the mass ratio of the crude difluoromethane raw material flow to the methanol-zinc powder slurry flow in S1 is 2-5, the methanol-zinc powder slurry flow comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry flow is 5-15.

Preferably, the gas phase production mixed gas stream in S1 comprises difluoromethane, hydrogen fluoride, difluoromethane monochloride, difluorodichloromethane, water and methanol, and the waste stream comprises zinc chloride and zinc hydroxide.

Preferably, the lights stream in S2 includes nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane, and carbon tetrafluoride; the heavies stream in S3 includes methyl chloride, methanol, and water.

Preferably, the number of theoretical plates of the light component removal tower in the S2 is 40-60, and the reflux ratio is 100-200.

Preferably, the theoretical plate number of the heavy component removal tower in the S3 is 60-80, and the reflux ratio is 3-8.

The reaction principle in the bubble reactor in S1 is:

(1) methanol reacts with hydrogen fluoride as follows:

CH₃OH+HF＝CH₃F+H₂O

hydrogen fluoride is converted into monofluoromethane which can be easily separated through the subsequent rectification process, so that acid gas is prevented from entering a subsequent rectification separation system;

(2) zinc powder is used for reduction dechlorination, and chlorofluoromethane with the boiling point close to that of difluoromethane is removed, and the reaction is as follows:

2CHClF₂+2Zn+2H₂O＝2CH₂F₂+ZnCl₂+Zn(OH)₂

CCl₂F₂+2Zn+2H₂O＝CH₂F₂+ZnCl₂+Zn(OH)₂

converting difluorodichloromethane which forms azeotropy with difluoromethane into difluoromethane product through zinc powder dechlorination reaction; meanwhile, the monochlorodifluoromethane is converted into a difluoromethane product, so that the separation difficulty in the subsequent rectification process is reduced; the methanol is complexed with the zinc chloride generated by the reaction, is separated from the surface of the zinc, exposes the zinc inside, and can continue to reduce and dechlorinate.

The mixed gas stream obtained after the pretreatment reaction is easier to remove other impurity components in the subsequent rectification process, and simultaneously, the optimal reaction conditions of the light component removal tower and the heavy component removal tower in the subsequent rectification process, such as temperature, tower plate number, pressure and the like, are determined.

Compared with the prior art, the invention has the following advantages:

1. according to the invention, impurities such as hydrogen fluoride, water, difluorochloromethane, difluorodichloromethane and the like are removed by adopting a bubbling reactor, and the hydrogen fluoride is converted into monofluoromethane which is easy to separate in the subsequent rectification process by using methanol, so that acid gas is prevented from entering a subsequent rectification separation system; converting difluorodichloromethane which forms azeotropy with difluoromethane into difluoromethane product through zinc powder dechlorination reaction; meanwhile, the monochlorodifluoromethane is converted into a difluoromethane product, so that the separation difficulty in the subsequent rectification process is reduced; the methanol is complexed with the zinc chloride generated by the reaction, is separated from the surface of the zinc, exposes the zinc inside, and can continue to reduce and dechlorinate.

2. According to the invention, the bubbling reactor is adopted, impurities which are difficult to separate are removed firstly, and then the light component and heavy component impurities are removed by using 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 extracting and rectifying the water and the hydrogen fluoride in a rectifying 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, the low-temperature rectification dehydration is realized, and the additional adsorption dehydration process is avoided.

The technical solution of the present invention is further described in detail by the accompanying drawings and examples.

Drawings

FIG. 1 is a schematic view of the structure of the purification apparatus of the present invention.

Description of reference numerals:

1-a crude difluoromethane feed stream; 2-a methanol-zinc dust slurry stream; 3-a waste stream; 4-a mixed gas stream; 5-a lights stream; 6-a stream comprising difluoromethane, methyl chloride, methanol and water; 7-an electronic grade difluoromethane product stream; 8-a heavy ends stream; r101-bubbling reactor; t101-lightness-removing tower; t102-heavy component removal tower; e101, a first condenser; e102, a second condenser; e103-reboiler one; e104-condenser III; e105-reboiler II.

Detailed Description

Example 1

Purification device of electron level difluoromethane in this embodiment, including the prereactor and with the second grade rectification system that the prereactor is connected, the prereactor is bubbling reactor R101, second grade rectification system is including lightness-removing tower T101 and heavy-removing tower T102 that connect gradually, bubbling reactor R101 upper end export is provided with a condenser E101, a condenser E101 and lightness-removing tower T101 inlet pipe connection, lightness-removing tower T101's top of the tower is provided with two condenser E102, and the tower cauldron is provided with reboiler E103, the top of the tower of heavy-removing tower T102 is provided with three condenser E104, and the tower cauldron reboiler is provided with two E105, reboiler E103 with heavy-removing tower T102 inlet pipe connection. 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 in the following specification (mass percent): crude difluoromethane with a purity of 98.60%, its impurities included 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% methyl chloride, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluorodichloromethane, and 0.1% water.

The method for purifying electronic grade trifluoromethane using the apparatus of example 1 of this example comprises the following steps:

s1, introducing a crude difluoromethane raw material flow 1 through a lower end inlet pipeline of a bubble reactor R101, introducing a methanol-zinc powder slurry flow 2 through an upper end inlet pipeline, performing pretreatment reaction, discharging a waste material flow 3 from a bottom outlet of the bubble reactor R101 after the reaction, condensing and refluxing partial methanol through a condenser E101 on an upper end outlet flow, and extracting a mixed gas flow 4 from a gas phase; the operating temperature of the bubbling reactor R101 is 90 ℃, and the operating pressure is 0.3 MPa; the mass flow of a crude difluoromethane raw material flow 1 introduced into a bubbling reactor R101 is 100kg/hr, the mass flow of a methanol-zinc powder slurry flow 2 is 44kg/hr, and the mass ratio of the crude difluoromethane raw material flow 1 to the methanol-zinc powder slurry flow 2 is 1: 3, the methanol-zinc powder slurry material flow 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry material flow 2 is 1: 10;

the purity of difluoromethane in the mixed gas stream 4 is 98.99 wt%, the content of hydrogen fluoride is 0.1ppm, the content of monochlorodifluoromethane is lower than 0.1ppm, the content of dichlorodifluoromethane is lower 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 be lower than 0.1ppm after passing through a bubbling reactor R101, the requirements of final products are met, and the contents of methanol and water are increased; waste stream 3 comprises zinc chloride and zinc hydroxide;

the mixed gas stream 4 in S2 and S1 passes through the condenser I E101 and then is fed into a light component removal tower T101 for primary rectification to remove light components, the operating temperature of the light component removal tower T101 is-37 ℃, the operating pressure is 2bar, the number of theoretical plates is 40, the inlet pipeline position of the light component removal tower is arranged at the 20 th plate, the reflux rate is 200kg/h, the reflux ratio is 100, a light component stream 5 is extracted from the gas phase of the top of the light component removal tower T101 through the condenser II E102, and a stream 6 comprising difluoromethane, methane chloride, methanol and water is extracted from the tower bottom through the reboiler I E103; light component stream 5 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;

introducing the material flow 6 containing difluoromethane, monochloromethane, methanol and water in S3 and S2 into an inlet pipeline of a de-heavy tower T102 through a reboiler I E103, carrying out secondary rectification in the de-heavy tower T102 to remove heavy components, wherein the operation temperature of the de-heavy tower T102 is-33 ℃, the operation pressure is 2bar, the theoretical plate number is 60, the inlet pipeline position of the de-heavy tower is at a 20 th plate, the reflux ratio is 3, an electronic-grade difluoromethane product material flow 7 is extracted from the top of the de-heavy tower T102 through a condenser III E104 in a gas phase, and a heavy component material flow 8 is extracted from a tower kettle through a reboiler II E105; the mass flow of stream 6 containing difluoromethane, monochloromethane, methanol and water was 98kg/hr, with a difluoromethane purity of 99.27 wt%; the heavies stream 8 comprises methyl chloride, methanol, and water;

through detection: the mass flow of the electronic-grade difluoromethane 7 is 94kg/hr, the purity reaches more than 99.998 wt%, 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, other fluorocarbons are less than 10ppm, and the total amount of impurities is not more than 20 ppm.

Example 3

The crude difluoromethane feed stream 1 used in this example was in the following specification (mass percent): crude difluoromethane with a purity of 98.60%, its impurities included 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% methyl chloride, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluorodichloromethane, and 0.1% water.

The method for purifying electronic grade trifluoromethane using the apparatus of example 1 of this example comprises the following steps:

s1, introducing a crude difluoromethane raw material flow 1 through a lower end inlet pipeline of a bubble reactor R101, introducing a methanol-zinc powder slurry flow 2 through an upper end inlet pipeline, performing pretreatment reaction, discharging a waste material flow 3 from a bottom outlet of the bubble reactor R101 after the reaction, condensing and refluxing partial methanol through a condenser E101 on an upper end outlet flow, and extracting a mixed gas flow 4 from a gas phase; the operating temperature of the bubbling reactor R101 is 100 ℃, and the operating pressure is 0.6 MPa; the mass flow of a crude difluoromethane raw material flow 1 introduced into a bubbling reactor R101 is 100kg/hr, the mass flow of a methanol-zinc powder slurry flow 2 is 48kg/hr, and the mass ratio of the crude difluoromethane raw material flow 1 to the methanol-zinc powder slurry flow 2 is 1:5, the methanol-zinc powder slurry material flow 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry material flow 2 is 1: 15;

the purity of difluoromethane in mixed gas stream 4 was 98.59 wt%, the hydrogen fluoride content was less than 0.1ppm, the difluoromethane content was less than 0.1ppm, the difluoromethylene chloride content was less than 0.1ppm, the water content was 0.2%, the methanol content was 0.4%; waste stream 3 comprises zinc chloride and zinc hydroxide;

the mixed gas stream 4 in S2 and S1 passes through the condenser I E101 and then is fed into a light component removal tower T101 for primary rectification to remove light components, the operation temperature of the light component removal tower T101 is-19 ℃, the operation pressure is 5bar, the number of theoretical plates is 50, the reflux ratio is 150, a light component stream 5 is extracted from the top of the light component removal tower T101 through the gas phase of the condenser II E102, and a stream 6 comprising difluoromethane, monochloromethane, methanol and water is extracted from the tower bottom through the reboiler I E103; light component stream 5 treasury nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;

introducing the material flow 6 containing difluoromethane, monochloromethane, methanol and water in S3 and S2 into an inlet pipeline of a heavy component removal tower T102 through a reboiler I E103, carrying out secondary rectification in the heavy component removal tower T102 to remove heavy components, wherein the operating temperature of the heavy component removal tower T102 is-9 ℃, the operating pressure is 5bar, the number of theoretical plates is 70, the reflux ratio is 5, an electronic-grade difluoromethane product material flow 7 is extracted from the top of the heavy component removal tower T102 through a condenser III E104 in a gas phase, and a heavy component material flow 8 is extracted from the bottom of the tower through a reboiler II E105; the mass flow of stream 6 containing difluoromethane, monochloromethane, methanol and water was 97kg/hr, with a difluoromethane purity of 99.08 wt%; the heavies stream 8 comprises methyl chloride, methanol, and water;

through detection: the mass flow of the electronic grade difluoromethane product material flow 7 is 94kg/hr, the purity reaches more than 99.998 wt%, 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, other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20 ppm.

Example 4

The crude difluoromethane feed stream 1 used in this example was in the following specification (mass percent): crude difluoromethane with a purity of 98.60%, its impurities included 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% methyl chloride, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluorodichloromethane, and 0.1% water.

The method for purifying electronic grade trifluoromethane using the apparatus of example 1 of this example comprises the following steps:

s1, introducing a crude difluoromethane raw material flow 1 through a lower end inlet pipeline of a bubble reactor R101, introducing a methanol-zinc powder slurry flow 2 through an upper end inlet pipeline, performing pretreatment reaction, discharging a waste material flow 3 from a bottom outlet of the bubble reactor R101 after the reaction, condensing and refluxing partial methanol through a condenser E101 on an upper end outlet flow, and extracting a mixed gas flow 4 from a gas phase; the operating temperature of the bubbling reactor R101 is 105 ℃, and the operating pressure is 1.0 MPa; the mass flow of a crude difluoromethane raw material flow 1 introduced into a bubbling reactor R101 is 100kg/hr, the mass flow of a methanol-zinc powder slurry flow 2 is 48kg/hr, and the mass ratio of the crude difluoromethane raw material flow 1 to the methanol-zinc powder slurry flow 2 is 1: 2, the methanol-zinc powder slurry material flow 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry material flow 2 is 1: 5;

the purity of difluoromethane in mixed gas stream 4 is 98.99 wt%, the content of hydrogen fluoride is lower than 0.1ppm, the content of difluoromethane is lower than 0.1ppm, the content of difluoromethylene chloride is lower than 0.1ppm, the content of water is 0.4%, the content of methanol is 0.4%; waste stream 3 comprises zinc chloride and zinc hydroxide;

the mixed gas stream 4 in S2 and S1 passes through the first condenser E101 and then is fed into a light component removal tower T101 for primary rectification to remove light components, the operating temperature of the light component removal tower T101 is-0.4 ℃, the operating pressure is 8bar, the number of theoretical plates is 60, the reflux ratio is 200, a light component stream 5 is extracted from the top of the light component removal tower T101 through the second condenser E102 in a gas phase, and a stream 6 comprising difluoromethane, monochloromethane, methanol and water is extracted from the bottom of the tower through the first reboiler E103; light component stream 5 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;

introducing the material flow 6 containing difluoromethane, monochloromethane, methanol and water in S3 and S2 into an inlet pipeline of a heavy component removal tower T102 through a reboiler I E103, carrying out secondary rectification in the heavy component removal tower T102 to remove heavy components, wherein the operating temperature of the heavy component removal tower T102 is-10 ℃, the operating pressure is 6bar, the number of theoretical plates is 80, the reflux ratio is 6, an electronic-grade difluoromethane product material flow 7 is extracted from the top of the heavy component removal tower T102 through a condenser III E104 in a gas phase, and a heavy component material flow 8 is extracted from the bottom of the tower through a reboiler II E105; the mass flow of stream 6 containing difluoromethane, monochloromethane, methanol and water was 97kg/hr, with a difluoromethane purity of 99.08 wt%; the heavies stream 8 comprises methyl chloride, methanol, and water;

through detection: the mass flow of the electronic grade difluoromethane product material flow 7 is 94kg/hr, the purity reaches more than 99.998 wt%, 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, other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20 ppm.

Example 5

The crude difluoromethane feed stream 1 used in this example was in the following specification (mass percent): crude difluoromethane with a purity of 98.60%, its impurities included 0.01% nitrogen, 0.01% oxygen, 0.01% carbon monoxide, 0.05% carbon dioxide, 0.01% methane, 0.1% hydrogen fluoride, 0.5% methyl chloride, 0.2% trifluoromethane, 0.01% ethane, 0.2% carbon tetrafluoride, 0.1% difluoromethane chloride, 0.1% difluorodichloromethane, and 0.1% water.

The method for purifying electronic grade trifluoromethane using the apparatus of example 1 of this example comprises the following steps:

s1, introducing a crude difluoromethane raw material flow 1 through a lower end inlet pipeline of a bubble reactor R101, introducing a methanol-zinc powder slurry flow 2 through an upper end inlet pipeline, performing pretreatment reaction, discharging a waste material flow 3 from a bottom outlet of the bubble reactor R101 after the reaction, condensing and refluxing partial methanol through a condenser E101 on an upper end outlet flow, and extracting a mixed gas flow 4 from a gas phase; the operating temperature of the bubbling reactor R101 is 110 ℃, and the operating pressure is 1.0 MPa; the mass flow of a crude difluoromethane raw material flow 1 introduced into a bubbling reactor R101 is 100kg/hr, the mass flow of a methanol-zinc powder slurry flow 2 is 48kg/hr, and the mass ratio of the crude difluoromethane raw material flow 1 to the methanol-zinc powder slurry flow 2 is 1: 4, the methanol-zinc powder slurry material flow 2 comprises methanol and zinc powder, and the mass ratio of the methanol to the zinc powder in the methanol-zinc powder slurry material flow 2 is 1: 13;

the purity of difluoromethane in mixed gas stream 4 is 98.99 wt%, the content of hydrogen fluoride is lower than 0.1ppm, the content of difluoromethane is lower than 0.1ppm, the content of difluoromethylene chloride is lower than 0.1ppm, the content of water is 0.4%, the content of methanol is 0.4%; waste stream 3 comprises zinc chloride and zinc hydroxide;

the mixed gas stream 4 in S2 and S1 passes through the condenser I E101 and then is fed into a light component removal tower T101 for primary rectification to remove light components, the operation temperature of the light component removal tower T101 is 7 ℃, the operation pressure is 10bar, the number of theoretical plates is 60, the reflux ratio is 200, a light component stream 5 is extracted from the top of the light component removal tower T101 through the condenser II E102 in a gas phase, and a stream 6 comprising difluoromethane, monochloromethane, methanol and water is extracted from the tower bottom through the reboiler I E103; light component stream 5 comprises nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, trifluoromethane, ethane, monofluoromethane and carbon tetrafluoride;

introducing the material flow 6 containing difluoromethane, monochloromethane, methanol and water in S3 and S2 into an inlet pipeline of a heavy component removal tower T102 through a reboiler I E103, carrying out secondary rectification in the heavy component removal tower T102 to remove heavy components, wherein the operation temperature of the heavy component removal tower T102 is 0 ℃, the operation pressure is 10bar, the number of theoretical plates is 80, the reflux ratio is 8, an electronic-grade difluoromethane product material flow 7 is extracted from the top of the heavy component removal tower T102 through a condenser III E104 in a gas phase, and a heavy component material flow 8 is extracted from the bottom of the tower through a reboiler II E105; the mass flow of stream 6 containing difluoromethane, monochloromethane, methanol and water was 97kg/hr, with a difluoromethane purity of 99.08 wt%; the heavies stream 8 comprises methyl chloride, methanol, and water;

through detection: the mass flow of the electronic grade difluoromethane product material flow 7 is 94kg/hr, the purity reaches more than 99.998 wt%, 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, other fluorocarbon is less than 10ppm, and the total amount of impurities is not more than 20 ppm.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, change and equivalent changes of the above embodiments according to the technical essence of the invention are still within the protection scope of the technical solution of the invention.