CN113233422B - Method and system for separating SiF4 and HF mixed gas - Google Patents
Method and system for separating SiF4 and HF mixed gas Download PDFInfo
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- CN113233422B CN113233422B CN202110614281.XA CN202110614281A CN113233422B CN 113233422 B CN113233422 B CN 113233422B CN 202110614281 A CN202110614281 A CN 202110614281A CN 113233422 B CN113233422 B CN 113233422B
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Abstract
The invention discloses a method and a system for separating SiF4 and HF mixed gas, which are used for separating SiF4 from HF mixed gas 4 Introducing the HF mixed gas and hydrogen into a microwave heating device, and rapidly heating the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen to 600-1200 ℃ by the microwave heating device to generate silicon and hydrogen fluoride gas; then, the generated silicon and hydrogen fluoride gas and the unreacted silicon tetrafluoride gas and hydrogen gas enter a gas-solid separation device together, silicon is separated out, and the rest gas is introduced into a condenser together; the hydrogen fluoride gas is condensed into hydrogen fluoride condensed liquid, the hydrogen fluoride condensed liquid enters a rectifying tower for further purification to obtain high-purity hydrogen fluoride, and unreacted hydrogen and silicon tetrafluoride gas return to the microwave heating device for reaction; according to the invention, hydrogen and silicon tetrafluoride gas are circulated in the system, so that silicon tetrafluoride is continuously reduced to generate hydrogen fluoride, and then high-purity hydrogen fluoride is obtained through condensation and rectification.
Description
Technical Field
The invention relates to the technical field of fluorine chemical industry, in particular to SiF 4 A method and a system for separating HF mixed gas.
Background
Anhydrous hydrogen fluoride (hydrogen fluoride) has a boiling point of 19.5 ℃ at normal pressure, is a colorless fuming liquid at the temperature of less than 19.5 ℃, is easy to polymerize and extremely volatile, emits white smoke when placed in the air, and violently releases heat to form hydrofluoric acid when dissolved in water; the silicon tetrafluoride has strong corrosivity, can corrode glass and silicate to generate gaseous silicon tetrafluoride, but does not corrode polyethylene, lead and platinum; hydrogen fluoride is a raw material for producing a refrigerant "freon", a fluorine-containing resin, an organic fluoride, and fluorine. The hydrogen fluoride can be used as a catalyst for organic synthesis such as alkylation, polymerization, condensation, isomerization and the like in chemical production; the method is also used for corroding strata during mining of certain mineral deposits and extracting rare earth elements and radioactive elements; in the atomic energy industry and nuclear weapons production, the raw material for manufacturing uranium hexafluoride, the raw material for producing rocket fuel and additives, and the raw material can be used for corroding glass, impregnating wood and the like.
In the process of preparing polycrystalline silicon by using silicon tetrafluoride and hydrogen, a large amount of hydrogen fluoride is generated, silicon tetrafluoride gas is mixed in a large amount of hydrogen fluoride gas, and if the mixed gas is directly discharged, atmospheric pollution and resource waste are caused. In the prior art, the technical means for separating and purifying hydrogen fluoride is difficult to obtain high-purity hydrogen fluoride products, the separated hydrogen fluoride can be put into the industrial application only by further processing, and a large amount of energy is consumed in the separation process.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a SiF 4 A method and a system for separating HF mixed gas, which at least achieve the purposes of obtaining a hydrogen fluoride product with higher purity and saving energy.
The purpose of the invention is realized by the following technical scheme: siF 4 A separation method of HF mixed gas relates to a microwave heating device, a gas-solid separation device, a condenser and a rectifying tower, and comprises the following steps:
s1, introducing mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device, and rapidly heating the mixed gas of the silicon tetrafluoride, the hydrogen fluoride and the hydrogen to 600-1200 ℃ through the microwave heating device;
s2, introducing the mixed gas heated by the microwave heating device and the generated silicon into a gas-solid separation device for separation;
s3, introducing the mixed gas separated by the gas-solid separation device into a condenser;
s4, introducing the liquid generated by the condenser into a rectifying tower for rectification, introducing the residual gas condensed by the condenser into the microwave heating device, and repeating the steps S1-S3;
s5, collecting the liquid separated from the rectifying tower, introducing the gas separated from the rectifying tower into the microwave heating device, and repeating the steps S1-S4.
The microwave heating device is used for heating, so that the heating is more uniform and sufficient, the effective collision among molecules can be increased, the reaction limit of silicon tetrafluoride and hydrogen is improved, hydrogen fluoride gas and silicon simple substance are generated, and the content of the silicon tetrafluoride gas in the hydrogen fluoride gas is effectively reduced; the microwave heating has strong penetrability and high heating speed, the heating is started from the inside of the substance, the heat dissipation is less, the heat loss is basically avoided, and the energy can be saved by 30-50% compared with the common heating mode; then, condensing the reacted mixed gas of hydrogen fluoride, hydrogen and silicon tetrafluoride by using a condenser to obtain condensed hydrogen fluoride condensate, circulating the uncondensed silicon tetrafluoride gas and hydrogen fluoride gas to the microwave heater for further reaction, introducing the hydrogen fluoride condensate into the rectifying tower for rectification to obtain a high-purity hydrogen fluoride product, and feeding the silicon tetrafluoride gas generated during rectification into the microwave heater again for reaction; the above steps are repeated in a circulating way, so that a high-purity hydrogen fluoride product can be obtained, the atom utilization rate of the reaction can be improved, and the energy is saved.
Further, the condensing temperature is-13-8 ℃ and the pressure is 0.4-0.6 MPa when the hydrogen fluoride gas is condensed by the condenser; so that the hydrogen fluoride gas is condensed into liquid while the silicon tetrafluoride gas and the hydrogen gas are not substantially condensed.
Furthermore, the volume of the introduced hydrogen is 4-8 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the purity of the hydrogen is 99.9999-99.99999%; promoting the silicon tetrafluoride gas to react and convert into hydrogen fluoride gas, and simultaneously taking the hydrogen as carrier gas to drive the unreacted silicon tetrafluoride, the hydrogen fluoride gas generated by the reaction and the silicon to flow in the system and enter the gas-solid separation device for gas-solid separation.
Further, when the hydrogen fluoride condensed liquid is rectified by the rectifying tower, the temperature of a tower kettle of the rectifying tower is 56-63 ℃, the temperature of a tower top of the rectifying tower is-23 ℃ to-18 ℃, and the operating temperature of the rectifying tower is 0.46MPa to 0.58MPa.
Further, when the rectification tower is used for rectification, the method comprises the following steps:
s41: feeding the liquid produced in the condenser in step S3 from the middle of the rectifying tower at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower reaches 58 ℃, controlling the operating pressure of the rectifying tower to be 0.51MPa, and controlling the condensing temperature at the top of the rectifying tower to be-22 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device for continuous reaction; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the bottom of the tower and is sent to a hydrogen fluoride storage tank for storage.
SiF 4 The separation system for the HF mixed gas comprises a microwave heating device, a gas-solid separation device, a condenser and a rectifying tower; the microwave heating device is communicated with the gas-solid separation device; the gas-solid separation device is communicated with the condenser; the lower end of the condenser is communicated with the rectifying tower; the top end of the condenser is communicated with the microwave heating device through a first circulating pipe and an air inlet pipe; the rectifying tower is communicated with the air inlet pipe through a second circulating pipe so as to be communicated with the microwave heating device; and a gas flowmeter is arranged at one end of the gas inlet pipe, which is far away from the first circulating pipe and the second circulating pipe.
The reaction cavity is heated uniformly by the microwave source and is further heated by the heat absorbed by the microwave absorbing layer, so that the reaction limit of silicon tetrafluoride and hydrogen can be improved, the silicon tetrafluoride gas and the hydrogen fluoride gas are further separated, and a hydrogen fluoride product with higher purity is obtained; the rectification tower rectifies the condensed hydrogen fluoride liquid to obtain high-purity hydrogen fluoride which can be directly used in other industries.
Further, the microwave heating device comprises a heating body, a reaction cavity which is arranged in a curve shape is arranged in the heating body, a catalyst layer is attached to the inner wall of the reaction cavity, and a microwave absorption layer is abutted to the outside of the reaction cavity; a microwave source is arranged on one side of the microwave absorption layer, which is far away from the reaction cavity; a heat insulation layer is arranged on one side of the microwave source away from the microwave absorption layer; one side of the heat insulation layer, which is far away from the microwave source, is abutted against the heating body; the catalyst layer accelerates the reaction rate of the hydrogen and the silicon tetrafluoride gas and shortens the reaction time.
Further, the gas-solid separation device comprises a separation device body, a plurality of first positioning grooves are arranged on the upper inner wall of the separation device body at intervals, second positioning grooves are correspondingly arranged on the lower inner wall of the separation device body right below the first positioning grooves, and a fiber gas-solid filter screen is fixedly connected between the corresponding first positioning grooves and the corresponding second positioning grooves; the fiber solid-gas filter screen is vertical to the bottom surface of the separation device body; after the hydrogen carries unreacted silicon tetrafluoride gas and hydrogen fluoride gas and the generated silicon simple substance passes through the gas-solid separation device, the silicon simple substance is filtered by the fiber solid gas filter screen and then is left in the gas-solid separation device, and the rest gas enters a condenser for next treatment.
Furthermore, one end of the first circulating pipe arranged on the condenser is communicated with a suction pump; the air pump is arranged in the condenser and fixedly connected with the top surface of the condenser
The invention has the beneficial effects that: when the mixed gas of silicon tetrafluoride and hydrogen fluoride is separated, silicon which can be directly used in other processes and a high-purity hydrogen fluoride product are obtained; the whole separation process of the silicon tetrafluoride and hydrogen fluoride mixed gas is simple, no by-product is generated, no environmental pollution is caused, and 50 percent of energy is saved at most.
Drawings
FIG. 1 is a schematic diagram of a mixed gas separation system according to the present invention;
1-a microwave heating device, 11-a reaction cavity, 12-a microwave absorption layer, 13-a microwave source and 14-a heat insulation layer; 2-a gas-solid separation device, 21-a first positioning groove, 22-a fiber gas-solid filter screen and 23-a second positioning groove; 3-a condenser, 4-a rectifying tower, 5-an air pump, 6-a first circulating pipe, 7-a second circulating pipe and 8-a gas flowmeter.
Detailed Description
The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.
SiF 4 The separation system with HF mixed gas comprises a microwave heating device 1 and a gas-solid separation device2. A condenser 3 and a rectifying tower 4; the microwave heating device 1 is communicated with the gas-solid separation device 2; the gas-solid separation device 2 is communicated with the condenser 3; the lower end of the condenser 3 is communicated with the rectifying tower 4; the top end of the condenser 3 is communicated with an air inlet pipe through a first circulating pipe 6 so as to be communicated with the microwave heating device 1; the rectifying tower 4 is communicated with the air inlet pipe through a second circulating pipe 7 so as to be communicated with the microwave heating device 1; one end of the air inlet pipe, which is far away from the first circulation pipe 6 and the second circulation pipe 7, is provided with a gas flowmeter 8.
SiF 4 The separation system for HF mixed gas comprises a microwave heating device 1, a gas-solid separation device 2, a condenser 3 and a rectifying tower 4; the microwave heating device 1 is communicated with the gas-solid separation device 2; the gas-solid separation device 2 is communicated with the condenser 3; the lower end of the condenser 3 is communicated with the rectifying tower 4; the top end of the condenser 3 is communicated with an air inlet pipe through a first circulating pipe 6 so as to be communicated with the microwave heating device 1; the rectifying tower 4 is communicated with the air inlet pipe through a second circulating pipe 7 so as to be communicated with the microwave heating device 1; one end of the air inlet pipe, which is far away from the first circulating pipe 6 and the second circulating pipe 7, is provided with a gas flowmeter 8; the microwave heating device 1 comprises a heating body, a reaction cavity 11 which is arranged in a curve shape is arranged in the heating body, a catalyst layer is attached to the inner wall of the reaction cavity 11, and a microwave absorption layer 12 is abutted to the outside of the reaction cavity 11; a microwave source 13 is arranged on one side of the microwave absorption layer 12 far away from the reaction cavity 11; a heat insulation layer 14 is arranged on one side of the microwave source 13 far away from the microwave absorption layer 12; the side of the insulating layer 14 remote from the microwave source 13 abuts the heating body.
As shown in FIG. 1, a SiF 4 The separation system for HF mixed gas comprises a microwave heating device 1, a gas-solid separation device 2, a condenser 3 and a rectifying tower 4; the microwave heating device 1 is communicated with the gas-solid separation device 2; the gas-solid separation device 2 is communicated with the condenser 3; the lower end of the condenser 3 is communicated with the rectifying tower 4; the top end of the condenser 3 is communicated with an air inlet pipe through a first circulating pipe 6 so as to be communicated with the microwave heating device 1; the rectifying tower 4 passes through the secondThe circulating pipe 7 is communicated with the air inlet pipe to be communicated with the microwave heating device 1; one end of the air inlet pipe, which is far away from the first circulating pipe 6 and the second circulating pipe 7, is provided with a gas flowmeter 8; the microwave heating device 1 comprises a heating body, a reaction cavity 11 which is arranged in a curve shape is arranged in the heating body, a catalyst layer is attached to the inner wall of the reaction cavity 11, and a microwave absorption layer 12 is abutted to the outside of the reaction cavity 11; a microwave source 13 is arranged on one side of the microwave absorption layer 12 far away from the reaction cavity 11; a heat insulation layer 14 is arranged on one side of the microwave source 13 far away from the microwave absorption layer 12; the side of the heat insulation layer 14 far away from the microwave source 13 is abutted against the heating body; the gas-solid separation device 2 comprises a separation device body, a plurality of first positioning grooves 21 are arranged on the upper inner wall of the separation device body at intervals, second positioning grooves 23 are correspondingly arranged on the lower inner wall of the separation device body right below the first positioning grooves 21, and a fiber gas-fixing filter screen 22 is fixedly connected between the corresponding first positioning grooves 21 and the corresponding second positioning grooves 23; the fiber solid-gas filter screen 22 is arranged perpendicular to the bottom surface of the separation device body; one end of the first circulating pipe 6 arranged on the condenser 3 is communicated with the air suction pump 5; the air pump 5 is arranged in the condenser 3, and the air pump 5 is fixedly connected with the top surface of the condenser 3.
The condenser 3 is preferably an LQF-series graphite quench tower; the rectifying tower 4 is preferably a 4 ZXT-graphite rectifying tower; the microwave source 13 is preferably a MUEGGE microwave generator
Example 1
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 4 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 600 ℃ through the microwave heating device 1 when the purity of the hydrogen is 99.9999%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-11 ℃, and the pressure is 0.6MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower kettle 4 of the rectifying tower reaches 56 percent of the height of the tower kettle after feeding, heating to ensure that the temperature of the tower kettle 4 of the rectifying tower reaches 56 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.46MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-23 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 2
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 8 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 1200 ℃ through the microwave heating device 1 when the purity of the hydrogen is 99.99999%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-13 ℃, and the pressure is 0.53MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower 4 reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower 4 reaches 58 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.51MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-22 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 3
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and the method comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 5 times of that of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 600 ℃ through the microwave heating device 1 when the purity of the hydrogen is 99.99999%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-13 ℃, and the pressure is 0.6MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower kettle 4 of the rectifying tower reaches 56 percent of the height of the tower kettle after feeding, heating to ensure that the temperature of the tower kettle 4 of the rectifying tower reaches 58 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.51MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-22 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 4
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 5 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 1200 ℃ by the microwave heating device 1 when the purity of the hydrogen is 99.9999%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-13 ℃, and the pressure is 0.6MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower 4 reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower 4 reaches 58 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.51MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-22 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 5
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 4 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the purity of the hydrogen is 99.99993%, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 890 ℃ through the microwave heating device 1;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-12 ℃, and the pressure is 0.57MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower 4 reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower 4 reaches 61 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.51MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-22 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 6
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 6 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 890 ℃ through the microwave heating device 1 when the purity of the hydrogen is 99.99995%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-11 ℃, and the pressure is 0.4MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower 4 reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower 4 reaches 56 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.46MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-18 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 7
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 5 times of that of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 890 ℃ through the microwave heating device 1 when the purity of the hydrogen is 99.99996%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-11 ℃, and the pressure is 0.53MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower 4 reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower 4 reaches 58 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.51MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-21 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Example 8
SiF 4 A separation method of HF mixed gas relates to the gas separation system, and comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, wherein the volume of the introduced hydrogen is 6 times of the volume of the mixed gas of silicon tetrafluoride and hydrogen fluoride, and the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen is rapidly heated to 890 ℃ through the microwave heating device 1 when the purity of the hydrogen is 99.99999%;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-11 ℃, and the pressure is 0.6MPa;
s41: introducing the residual gas condensed by the condenser 3 into the microwave heating device 1, repeating the steps S1-S3, and feeding the liquid generated by the condenser 3 in the step S3 from the middle part of the rectifying tower 4 at a feeding speed of 1 kg/h;
s42: when the liquid level of the tower kettle 4 of the rectifying tower reaches 56 percent of the height of the tower kettle after feeding, heating to ensure that the temperature of the tower kettle 4 of the rectifying tower reaches 63 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.58MPa, and controlling the condensing temperature at the top of the rectifying tower 4 to be-23 ℃;
s43: feeding the mixed gas extracted from the top of the tower into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S4 on the extracted mixed gas; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4.
Comparative example 1:
SiF 4 A method for separating HF mixed gas relates to a gas-solid separation device 2, a condenser 3 and a rectifying tower 4 of the separation system in embodiment 1, and comprises the following steps:
s1, introducing mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a common heating device, and rapidly heating the mixed gas of the silicon tetrafluoride, the hydrogen fluoride and the hydrogen to 890 ℃ through the common heating device;
s2, introducing the mixed gas heated by the common heating device and the generated silicon into a gas-solid separation device 2 for separation;
s3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-11 ℃, and the pressure is 0.53MPa;
s41: feeding the liquid produced in the condenser 3 in step S3 from the middle of the rectification column 4 at a feed rate of 1 kg/h;
s42: when the liquid level of the tower bottom of the rectifying tower 4 reaches 56% of the height of the tower bottom after feeding, heating to ensure that the temperature of the tower bottom of the rectifying tower 4 reaches 58 ℃, controlling the operating pressure of the rectifying tower 4 to be 0.51MPa, and controlling the temperature of a condenser 3 at the top of the rectifying tower 4 to be-22 ℃;
s43: sending the mixed gas extracted from the tower top into the microwave heating device 1 for continuous reaction, and repeating the steps S1-S3; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the tower bottom and is sent to a hydrogen fluoride storage tank for storage;
and S5, collecting the liquid separated from the rectifying tower 4, introducing the gas separated from the rectifying tower 4 into the microwave heating device 1, and repeating the steps S1-S4.
Comparative example 2
SiF 4 A separation method of HF mixed gas relates to a microwave heating device 1, a gas-solid separation device 2 and a condenser 3 in embodiment 1, and the method comprises the following steps:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device 1, and rapidly heating the mixed gas of the silicon tetrafluoride, the hydrogen fluoride and the hydrogen to 890 ℃ through the microwave heating device 1;
s2, introducing the mixed gas heated by the microwave heating device 1 and the generated silicon into a gas-solid separation device 2 for separation;
and S3, introducing the mixed gas separated by the gas-solid separation device 2 into a condenser 3 for condensation, wherein the condensation temperature of the condenser 3 is-11 ℃, and the pressure is 0.53MPa, so as to obtain a hydrogen fluoride product.
Table 1: examples 1-8, comparative example 1 and comparative example 2
As can be seen from table 1, the purity of the obtained hydrogen fluoride liquid is effectively improved by the microwave heating, and the purity of the obtained hydrogen fluoride liquid is further improved by the combination of the microwave heating, the condensation and the rectification, so that the high-purity hydrogen fluoride liquid is obtained, and the purity of the hydrogen fluoride obtained in example 8 is the highest, but is close to that of the hydrogen fluoride obtained in example 7, and the embodiment of example 7 is preferred in terms of economic cost.
The foregoing is illustrative of the preferred embodiments of this invention, and it is to be understood that the invention is not limited to the precise form disclosed herein and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the concept as disclosed herein, either as described above or as apparent to those skilled in the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (5)
1. SiF 4 The separation method of HF mixed gas is characterized by comprising the following steps of:
s1, introducing a mixed gas of silicon tetrafluoride and hydrogen fluoride and hydrogen into a microwave heating device (1), and rapidly heating the mixed gas of silicon tetrafluoride, hydrogen fluoride and hydrogen to 600-1200 ℃ through the microwave heating device (1);
s2, introducing the mixed gas heated by the microwave heating device (1) and the generated silicon into a gas-solid separation device (2) for separation;
s3, introducing the mixed gas separated by the gas-solid separation device (2) into a condenser (3); the condensing temperature of the condenser (3) for condensing the hydrogen fluoride gas is-13 ℃ to-8 ℃, and the pressure is 0.4MPa to 0.6MPa;
s4, introducing the residual gas condensed by the condenser (3) into the microwave heating device (1) to repeat the steps S1-S3, and introducing the liquid generated by the condenser (3) into a rectifying tower (4) for rectification;
and S5, introducing the gas separated from the rectifying tower (4) into the microwave heating device (1) to repeat the steps S1-S4, and collecting the liquid separated from the rectifying tower (4).
2. A SiF according to claim 1 4 The method for separating HF mixed gas is characterized in that: the volume of the introduced hydrogen is 4 to 8 times of the volume of the mixed gas of the silicon tetrafluoride and the hydrogen fluoride.
3. A SiF according to claim 2 4 The method for separating HF mixed gas is characterized in that: the purity of the introduced hydrogen is 99.9999-99.99999%.
4. A SiF according to claim 1 4 The method for separating HF mixed gas is characterized in that: when the rectifying tower (4) is used for rectifying in the S4, the tower kettle temperature of the rectifying tower (4) is 56-63 ℃, the tower top temperature of the rectifying tower (4) is-23-18 ℃, and the operating pressure of the rectifying tower (4) is 0.46-0.58 MPa.
5. A SiF according to claim 4 4 The method for separating HF mixed gas is characterized in that: when the rectification is carried out by utilizing the rectification tower (4), the method comprises the following steps:
s41: feeding the liquid produced in the condenser (3) of step S3 from the middle of the rectification column (4) at a feed rate of 1 kg/h;
s42: when the liquid level of the tower kettle of the rectifying tower (4) reaches 56% of the height of the tower kettle after feeding, heating to ensure that the temperature of the tower kettle of the rectifying tower (4) reaches 58 ℃, controlling the operating pressure of the rectifying tower (4) to be 0.51MPa, and controlling the top condensing temperature of the rectifying tower (4) to be-22 ℃;
s43: feeding the mixed gas extracted from the tower top into the microwave heating device (1) for continuous reaction; liquid hydrogen fluoride with the purity of more than or equal to 99.9wt% is extracted from the bottom of the tower and is sent to a hydrogen fluoride storage tank for storage.
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