Device and method for multi-stage flash evaporation purification of germanium tetrafluoride

Abstract

The invention discloses a device and a method for multi-stage flash evaporation purification of germanium tetrafluoride. The device comprises an impurity removal adsorption tank and a flash evaporation tower, the impurity removal adsorber is connected with a flash tower; the flash tower is connected with a first constant-temperature cold bath device, a second constant-temperature cold bath device and a third constant-temperature cold bath device; the impurity removal adsorption tank and the flash tower are connected with a vacuum pump; the flash tower comprises an upper section, a middle section and a lower end temperature control area; the impurity separation in germanium tetrafluoride is realized by simply setting temperature control interface parameters of the constant-temperature cold bath device and cooperating with the operation of the vacuum pump and the corresponding valve; by independently controlling the temperature of the three sections of the flash tower, impurities such as HF, N2 and O2 are effectively removed, a germanium tetrafluoride product with the purity of 3N is finally obtained, and the problem that germanium tetrafluoride is difficult to separate is solved.

Description

Technical Field

[0001] This invention relates to the field of purification and preparation technology, specifically to an apparatus and method for multi-stage flash evaporation purification of germanium tetrafluoride. Background Technology

[0002] Germanium tetrafluoride (GeF4), an important inorganic fluoride, is mainly used to produce isotopes such as germanium-76 and germanium-72, which are widely used in optical fiber communication, semiconductors, and other fields. In optical fiber communication, germanium tetrafluoride serves as a core dopant for quartz optical fibers, significantly improving fiber signal transmission performance. In the semiconductor field, germanium tetrafluoride is used for photolithography, etching, and doping of chips. However, current germanium tetrafluoride purification devices and methods require multiple adsorption towers and distillation towers connected in series to meet separation requirements. Furthermore, the distillation towers have complex structures and are difficult to operate, hindering their industrial application. Summary of the Invention

[0003] The purpose of this invention is to provide an apparatus and method for multi-stage flash evaporation purification of germanium tetrafluoride, thereby solving the problem of difficult separation and purification of germanium tetrafluoride.

[0004] The technical solution of the present invention is as follows: an apparatus for multi-stage flash evaporation purification of germanium tetrafluoride, comprising a purification adsorption tank and a flash evaporation tower; the purification adsorption tank is connected to the flash evaporation tower, and the flash evaporation tower is connected to a first constant temperature cold bath device, a second constant temperature cold bath device, and a third constant temperature cold bath device; the purification adsorption tank and the flash evaporation tower are connected to a vacuum pump; the flash evaporation tower includes an upper section, a middle section, and a lower temperature control zone.

[0005] The connection pipeline between the impurity removal adsorption tank and the flash evaporator has a first stop valve and a second stop valve. A sampling port is provided between the first stop valve and the second stop valve. The sampling port is controlled by a third stop valve. The connection pipeline between the impurity removal adsorption tank and the vacuum pump has a tenth stop valve and an eleventh stop valve. The connection pipeline between the flash evaporator and the vacuum pump has an eleventh stop valve.

[0006] The flash tower is connected to the first constant temperature cold bath device, and the fourth and fifth shut-off valves are respectively connected to the cold coal inlet and outlet pipelines of the first constant temperature cold bath device; the refrigerant pipeline of the first constant temperature cold bath device is wrapped around the tower plate of the upper section of the flash tower to form the upper temperature control zone.

[0007] The flash tower is connected to the second constant temperature cold bath device, and the sixth and seventh stop valves are respectively connected to the cold coal inlet and outlet pipelines of the second constant temperature cold bath device. The refrigerant pipeline of the second constant temperature cold bath device is wrapped around the tower plate in the middle section of the flash tower to form the middle temperature control zone.

[0008] The flash tower is connected to the third constant temperature cold bath device, and the eighth and ninth stop valves are respectively connected to the cold coal inlet and outlet pipelines of the third constant temperature cold bath device; the refrigerant pipeline of the third constant temperature cold bath device is wrapped around the tower plate of the lower section of the flash tower to form the lower temperature control zone.

[0009] The temperature control range of the first constant temperature cold bath device is -30 to 99℃, the temperature control range of the second constant temperature cold bath device is -60 to 99℃, and the temperature control range of the third constant temperature cold bath device is -80 to 99℃. The temperatures of the first, second, and third constant temperature cold bath devices are controlled independently.

[0010] The impurity removal adsorption tank is connected to a differential pressure transmitter and a temperature transmitter; the flash tower is connected to a pressure transmitter.

[0011] The lower layer of the impurity removal adsorption tank is filled with porous spherical sodium fluoride packing, and the upper layer is filled with molecular sieves.

[0012] A method for multi-stage flash evaporation purification of germanium tetrafluoride includes the following steps:

[0013] S1: Close the first shut-off valve, and the crude germanium tetrafluoride gas enters the bottom of the impurity removal adsorption tank through the pipeline to remove HF and CO2 from the crude germanium tetrafluoride gas;

[0014] S2: Open the fourth, fifth, sixth, seventh, eighth, and ninth shut-off valves; start the first, second, and third constant-temperature cold bath devices to control the temperature of the upper, middle, and lower temperature control zones of the flash tower; close the third and tenth shut-off valves; open the first and second shut-off valves; and when all the crude germanium tetrafluoride gas has entered the flash tower, close the first and second shut-off valves; the germanium tetrafluoride gas condenses into a solid in the flash tower.

[0015] S3: Start the vacuum pump and open the eleventh shut-off valve. The vacuum pump will evacuate the flash tower. After the evacuation is completed, close the eleventh shut-off valve and turn off the vacuum pump. Then heat up the flash tower so that the germanium tetrafluoride on the upper section of the flash tower will sublimate from solid to gas.

[0016] S4: The purified germanium tetrafluoride gas is discharged from the top of the flash tower and collected.

[0017] In S2, the temperature of the upper section temperature control zone of the flash tower is controlled at -65℃, the temperature of the middle section temperature control zone is controlled at -40℃, and the temperature of the lower section temperature control zone is controlled at -30℃ by the first constant temperature cold bath device, the second constant temperature cold bath device, and the third constant temperature cold bath device.

[0018] In step S2, the first shut-off valve is slowly opened to an opening degree of 1 / 10.

[0019] In S2, the impurities in the germanium tetrafluoride gas include HF, N2, and O2; at this time, HF is in liquid state and is located at the bottom of the flash tower, and HF is discharged from the bottom of the flash tower; while N2 and O2 are in gaseous state and are located at the top of the flash tower.

[0020] In step S2, the temperature of the upper section of the flash tower 2 is raised to -35°C, while the temperature of the middle and lower sections remains unchanged.

[0021] The significant advantages of this invention are:

[0022] (1) After the germanium tetrafluoride gas flows through the impurity removal adsorption tank, most of the CO2 and HF can be removed, which provides a guarantee for subsequent distillation and purification to obtain high-purity germanium tetrafluoride.

[0023] (2) By simply setting the temperature control interface parameters of the constant temperature cold bath device, and cooperating with the operation of the vacuum pump and corresponding valves, the impurities in germanium tetrafluoride can be separated.

[0024] (3) By controlling the three-stage temperature of the flash tower independently, impurities such as HF, N2, and O2 are effectively removed, and finally germanium tetrafluoride with a purity of 3N is obtained, solving the problem of difficult separation of germanium tetrafluoride. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an apparatus used for multi-stage flash evaporation purification of germanium tetrafluoride.

[0026] The markings in the diagram are as follows: 1-Impurity removal adsorption tank, 2-Flash evaporator, 3-Third constant temperature cold bath device, 4-Second constant temperature cold bath device, 5-First constant temperature cold bath device, 6-Vacuum pump. J1-First shut-off valve, J2-Second shut-off valve, J3-Third shut-off valve, J4-Fourth shut-off valve, J5-Fifth shut-off valve, J6-Sixth shut-off valve, J7-Seventh shut-off valve, J8-Eighth shut-off valve, J9-Ninth shut-off valve, J10-Tenth shut-off valve, J11-Eleventh shut-off valve. Detailed Implementation

[0027] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0028] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.

[0029] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first.

[0030] The specific technical content of the present invention will now be described with reference to the accompanying drawings;

[0031] A process apparatus for multi-stage flash evaporation purification of germanium tetrafluoride includes a purification adsorption tank 1, a flash evaporation tower 2, a vacuum pump 6, a first constant-temperature cold bath device 5, a second constant-temperature cold bath device 4, and a third constant-temperature cold bath device 3. The purification adsorption tank 1 is connected to the flash evaporation tower 2 via pipelines, and the flash evaporation tower 2 is connected to the first constant-temperature cold bath device 5, the second constant-temperature cold bath device 4, and the third constant-temperature cold bath device 3 via pipelines. The purification adsorption tank 1 and the flash evaporation tower 2 are connected to the vacuum pump 6 via pipelines.

[0032] Furthermore, a first shut-off valve J1 and a second shut-off valve J2 are installed on the pipeline between the impurity removal adsorption tank 1 and the flash tower 2. A sampling port is provided between the first shut-off valve J1 and the second shut-off valve J2, and the sampling port is controlled by a third shut-off valve J3.

[0033] The flash evaporator 2 and the first constant temperature cold bath device 5 are respectively connected to the fourth shut-off valve J4 and the fifth shut-off valve J5 on the cold coal inlet and outlet pipelines.

[0034] Flash evaporator 2 and the second constant temperature cold bath device 4 are respectively connected to the sixth stop valve J6 and the seventh stop valve J7 on the cold coal inlet and outlet pipelines.

[0035] The flash tower 2 and the third constant temperature cold bath device 3 are respectively connected to the eighth stop valve J8 and the ninth stop valve J9 on the cold coal inlet and outlet pipelines.

[0036] The adsorption tank 1 and the vacuum pump 6 are connected by a tenth shut-off valve J10 and an eleventh shut-off valve J11, and the flash tower 2 and the vacuum pump 6 are connected by an eleventh shut-off valve J11.

[0037] Furthermore, the temperature control range of the first constant temperature cold bath device 5 is -30 to 99°C, the temperature control range of the second constant temperature cold bath device 4 is -60 to 99°C, and the temperature control range of the third constant temperature cold bath device 3 is -80 to 99°C.

[0038] Furthermore, the three temperature sections of the flash tower 2 are independently controlled, and each of the three temperature control zones is connected to a constant-temperature cooling bath device. Each of the three temperature control zones in the flash tower 2 consists of three staggered layers of trays, with refrigerant circulation pipes tightly attached to each tray to improve cooling efficiency. The three temperature control sections of the flash tower 2 form an internal circulation system with the three constant-temperature cooling bath devices, ensuring the reliability of temperature control.

[0039] Furthermore, the impurity removal adsorption tank 1 is connected to a differential pressure and temperature transmitter; the flash tower 2 is connected to a pressure transmitter; and the three temperature control zones are respectively connected to temperature transmitters.

[0040] Furthermore, the lower layer of the impurity removal adsorption tank 1 is filled with porous spherical sodium fluoride packing material for removing HF, and the upper layer is filled with molecular sieves for removing CO2; the flash tower 2 is used to remove impurities such as HF, N2, and O2.

[0041] Furthermore, the constant temperature cold bath device uses anhydrous ethanol as a refrigerant.

[0042] Furthermore, the impurity removal adsorption tank 1 has a diameter of 147 mm and a height of 900 mm; the flash evaporation tower 2 has a diameter of 300 mm and a height of 1500 mm.

[0043] After analysis and testing, the germanium tetrafluoride product obtained from the flash distillation tower has a purity of 99.9%.

[0044] The specific work includes the following steps:

[0045] S1: Close the first shut-off valve J1. The crude germanium tetrafluoride gas enters the bottom of the impurity removal adsorption tank 1 through the pipeline. The HF in the crude germanium tetrafluoride gas is removed by the porous spherical sodium fluoride packing material in the lower layer of the impurity removal adsorption tank 1. The upper layer of the adsorption tank 1 is equipped with molecular sieves to remove CO2.

[0046] S2: Open the fourth shut-off valve J4, the fifth shut-off valve J5, the sixth shut-off valve J6, the seventh shut-off valve J7, the eighth shut-off valve J8, and the ninth shut-off valve J9; start the first constant temperature cold bath device 5, the second constant temperature cold bath device 4, and the third constant temperature cold bath device 3; through the first constant temperature cold bath device 5, the second constant temperature cold bath device 4, and the third constant temperature cold bath device 3, control the temperature of the upper section temperature control zone of the flash tower 2 to -65℃, the middle section temperature control zone to -40℃, and the lower section temperature control zone to -30℃; close the third shut-off valve J3 and the tenth shut-off valve. Slowly open the first shut-off valve J1 (J1 valve opening degree is 1 / 10), then open the second shut-off valve J2. Once all the crude germanium tetrafluoride gas has entered the flash tower 2, close the first shut-off valve J1 and the second shut-off valve J2. The crude germanium tetrafluoride gas remains in the flash tower 2 for 2 hours, condensing into a solid. Impurities in the germanium tetrafluoride gas include HF, N2, and O2. At this time, HF is in a liquid state and located at the bottom of the flash tower 2, and is discharged from the bottom of the flash tower 2. N2 and O2 are in a gaseous state and located at the top of the flash tower 2.

[0047] S3: Start vacuum pump 6 and open eleventh shut-off valve J11. Vacuum pump 6 evacuates flash tower 2, thereby extracting N2 and O2 to the tail gas system. After evacuation, close eleventh shut-off valve J11 and vacuum pump 6. Then raise the temperature of the upper section of flash tower 2 to -35℃, while keeping the temperature of the middle section and the lower section constant. This causes germanium tetrafluoride on the upper and middle sections of the flash tower 2 to sublimate from solid to gas.

[0048] S4: Discharge and collect the purified germanium tetrafluoride gas from the top of flash tower 2; after collection, close the fourth stop valve J4, the fifth stop valve J5, the sixth stop valve J6, the seventh stop valve J7, the eighth stop valve J8, and the ninth stop valve J9, and close the first constant temperature cold bath device 5, the second constant temperature cold bath device 4, and the third constant temperature cold bath device 3.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0050] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0051] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0052] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. An apparatus for multi-stage flash evaporation purification of germanium tetrafluoride, characterized in that: It includes a purification adsorption tank (1) and a flash tower (2); the purification adsorber (1) is connected to the flash tower (2), and the flash tower (2) is connected to the first constant temperature cold bath device (5), the second constant temperature cold bath device (4), and the third constant temperature cold bath device (3); the purification adsorption tank (1) and the flash tower (2) are connected to a vacuum pump (6); the flash tower (2) includes an upper section, a middle section, and a lower temperature control zone; The connection pipeline between the impurity removal adsorption tank (1) and the flash tower (2) has a first shut-off valve (J1) and a second shut-off valve (J2). A sampling port is provided between the first shut-off valve (J1) and the second shut-off valve (J2). The sampling port is controlled by a third shut-off valve (J3). The connection pipeline between the impurity removal adsorption tank (1) and the vacuum pump (6) has a tenth shut-off valve (J10) and an eleventh shut-off valve (J11). The connection pipeline between the flash tower (2) and the vacuum pump (6) has an eleventh shut-off valve (J11).

2. The apparatus for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 1, characterized in that: The flash tower (2) is connected to the first constant temperature cold bath device (5), and the fourth stop valve (J4) and the fifth stop valve (J5) are respectively connected to the cold coal inlet and outlet pipelines of the first constant temperature cold bath device (5); the refrigerant pipeline of the first constant temperature cold bath device (5) is wrapped around the tower plate of the upper section of the flash tower (2) to form the upper temperature control zone. The flash tower (2) is connected to the second constant temperature cold bath device (4), and the sixth stop valve (J6) and the seventh stop valve (J7) are respectively connected to the cold coal inlet and outlet pipelines of the second constant temperature cold bath device (4). The refrigerant pipeline of the second constant temperature cold bath device (4) is wrapped around the tower plate in the middle section of the flash tower (2) to form the middle section temperature control zone. The flash tower (2) is connected to the third constant temperature cold bath device (3), and the eighth stop valve (J8) and the ninth stop valve (J9) are respectively connected to the cold coal inlet and outlet pipelines of the third constant temperature cold bath device (3); the refrigerant pipeline of the third constant temperature cold bath device (3) is wrapped around the tower plate of the lower section of the flash tower (2) to form the lower temperature control zone.

3. The apparatus for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 2, characterized in that: The temperature control range of the first constant temperature cold bath device (5) is -30 to 99℃, the temperature control range of the second constant temperature cold bath device (4) is -60 to 99℃, and the temperature control range of the third constant temperature cold bath device (3) is -80 to 99℃. The temperatures of the first constant temperature cold bath device (5), the second constant temperature cold bath device (4), and the third constant temperature cold bath device (3) are independently controlled.

4. The apparatus for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 3, characterized in that: The impurity removal adsorption tank (1) is connected to a differential pressure transmitter and a temperature transmitter; the flash tower (2) is connected to a pressure transmitter.

5. The apparatus for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 4, characterized in that: The lower layer of the impurity removal adsorption tank (1) is filled with porous spherical sodium fluoride packing, and the upper layer is filled with molecular sieve.

6. A method for multi-stage flash evaporation purification of germanium tetrafluoride, using the apparatus described in claim 5, characterized in that: Includes the following steps: S1: Close the first shut-off valve (J1), and the crude germanium tetrafluoride gas enters the bottom of the impurity removal adsorption tank (1) through the pipeline to remove HF and CO2 from the crude germanium tetrafluoride gas; S2: Open the fourth shut-off valve (J4), fifth shut-off valve (J5), sixth shut-off valve (J6), seventh shut-off valve (J7), eighth shut-off valve (J8), and ninth shut-off valve (J9), and start the first constant temperature cold bath device (5), the second constant temperature cold bath device (4), and the third constant temperature cold bath device (3) to control the temperature of the upper, middle, and lower temperature control zones of the flash tower (2); close the third shut-off valve (J3) and the tenth shut-off valve (J10), open the first shut-off valve (J1), open the second shut-off valve (J2), and when all the crude germanium tetrafluoride gas has entered the flash tower (2), close the first shut-off valve (J1) and the second shut-off valve (J2); the germanium tetrafluoride gas condenses into a solid in the flash tower (2); S3: Start the vacuum pump (6), open the eleventh shut-off valve (J11), and the vacuum pump (6) evacuates the flash tower (2). After the evacuation is completed, close the eleventh shut-off valve (J11), turn off the vacuum pump (6), and then heat up the flash tower (2) so that the germanium tetrafluoride on the upper section of the flash tower (2) sublimates from solid to gas. S4: The purified germanium tetrafluoride gas is discharged from the top of the flash tower (2) and collected.

7. The method for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 6, characterized in that: In S2, the temperature of the upper section of the flash tower (2) is controlled at -65℃, the temperature of the middle section is controlled at -40℃, and the temperature of the lower section is controlled at -30℃ by the first constant temperature cold bath device (5), the second constant temperature cold bath device (4), and the third constant temperature cold bath device (3).

8. The method for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 6, characterized in that: In step S2, the first shut-off valve (J1) is slowly opened to an opening degree of 1 / 10.

9. The method for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 6, characterized in that: In S2, the impurities in the germanium tetrafluoride gas include HF, N2, and O2; at this time, HF is in liquid state and is located at the bottom of the flash tower (2), and HF is discharged from the bottom of the flash tower (2); while N2 and O2 are in gaseous state and are located at the top of the flash tower (2).

10. The method for multi-stage flash evaporation purification of germanium tetrafluoride according to claim 6, characterized in that: In S2, the temperature of the upper section of the flash tower (2) is raised to -35°C, while the temperature of the middle section and the lower section remain unchanged.

Images