Device for producing ultrapure phosphorane through differential pressure thermal coupling rectification

Abstract

The utility model provides a device for producing ultrapure phosphorane through differential pressure thermal coupling rectification. A first condensation reflux device is arranged at the top of a first rectifying tower, and a first reboiler is arranged at the bottom of the first rectifying tower; a second condensation reflux device is arranged at the top of the second rectifying tower, and a second reboiler is arranged at the bottom; the top of the first rectifying tower is sequentially connected with a second reboiler, a first condensation reflux device and a second rectifying tower through a conveying pipeline; a third condensation reflux device is arranged at the top of the third rectifying tower, and a third reboiler is arranged at the bottom; the bottom of the second rectifying tower is connected with the third rectifying tower. A diaphragm compressor is arranged at the top of the third rectifying tower, the pressure of a product is increased, normal-temperature filling can be guaranteed, and meanwhile, an outlet of the diaphragm compressor is connected with a first reboiler B, so that heat of a gas phase at the top of the third rectifying tower is fully utilized. The system and the device can effectively remove impurities such as H2O, O2, H2, C2H6, CH4, CO, SiH4, C2H4 and AsH3 in industrial hydrogen phosphide to obtain electronic-grade hydrogen phosphide; meanwhile, the energy consumption in the operation process is reduced, and the annual operation cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of electronic-grade special gas purification and detection technology, and in particular to an apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation. Background Technology

[0002] Electronic-grade phosphine, as an indispensable key electronic gas in semiconductor processes, possesses extremely high technical barriers and holds a leading position among similar products. It plays a crucial role in core processes such as ion implantation and doping. In the LED industry, especially in the epitaxial growth of GaAs-based LEDs, phosphine is a key raw material for GaAs and InAIP chemical vapor deposition. Furthermore, it is considered a core N-type dopant source in semiconductor device manufacturing. Moreover, phosphine is widely used in various fields, including polycrystalline silicon chemical vapor deposition, GaP material epitaxial growth, ion implantation processes, MOCVD processes, and the preparation of phosphosilicate glass passivation films.

[0003] The influence of electronic-grade phosphine extends beyond the aforementioned processes. It plays a crucial role in numerous high-tech fields, including chips, integrated circuits, liquid crystal displays, photovoltaics, aerospace, and defense, highlighting its irreplaceable importance.

[0004] Differential pressure heat-coupled distillation is a heat-coupled distillation process that, by selecting an appropriate operating pressure, ensures that the top temperature of a conventional distillation column is higher than the bottom temperature of a step-down distillation column. This allows the vapor at the top of the conventional distillation column to serve as a heat source for the step-down distillation column. This process achieves partial or complete heat coupling between the load of the condenser at the top of the conventional column and the reboiler at the bottom of the step-down column, thereby reducing heat loss.

[0005] CN 214287448U discloses a phosphine gas purification device, which purifies phosphine gas, a byproduct of sodium hypophosphite production. However, this device is difficult to purify to electronic grade phosphine.

[0006] CN 117339340 A discloses an electronic-grade phosphine purification system and method, in which the distillation columns are not thermally integrated, resulting in excessive steam consumption at the bottom of the columns and excessive electricity consumption at the top of the columns, leading to high operating costs. Summary of the Invention

[0007] The purpose of this invention is to provide a device for producing ultrapure phosphine by differential pressure thermal coupling distillation, so as to solve the problems of high energy consumption and high operating costs of phosphine purification systems in the prior art.

[0008] To solve the above-mentioned technical problems, the present invention provides a method for producing ultrapure phosphine by differential pressure thermal coupling distillation. The apparatus includes a heavy removal unit, a light removal unit, and a product unit. The heavy removal unit includes a first distillation column, with a first reflux condenser at the top and a first reboiler at the bottom. The light removal unit includes a second distillation column, with a second reflux condenser at the top and a second reboiler at the bottom. The top of the first distillation column is connected to the middle of the second distillation column via a conveying pipeline. The product unit includes a third distillation column, with a third reflux condenser at the top and a third reboiler at the bottom. The bottom of the second distillation column is connected to the third distillation column via a conveying pipeline.

[0009] Furthermore, the high-temperature gas phase at the top of the first distillation column first enters the second reboiler as a heat source, and then enters the first condenser reflux condenser. After being cooled by heat transfer oil, part of it is used as reflux for the first distillation column, and the other part is used as feed for the second distillation column. This fully utilizes the heat of the gas phase at the top of the column, saving the steam consumption of the second reboiler and the heat transfer oil consumption of the first condenser reflux condenser.

[0010] Furthermore, the high-temperature gas phase at the top of the second distillation column first enters the third reboiler as a heat source, and then enters the second condenser reflux condenser. After being cooled by heat transfer oil, it serves as the reflux of the second distillation column, so as to make full use of the heat of the gas phase at the top of the column and save the steam consumption of the third reboiler and the heat transfer oil consumption of the second condenser reflux condenser.

[0011] Furthermore, a diaphragm compressor is installed at the top of the third distillation column to pressurize the phosphine product, ensuring that it does not vaporize at a normal temperature of 25-35℃, thus enabling room temperature filling, reducing the amount of liquid nitrogen used during the filling process, and lowering the filling safety risks.

[0012] Furthermore, the vapor phase at the top of the third distillation column is pressurized and heated by the diaphragm compressor before entering the first reboiler B, serving as a partial reboiling heat source for the first distillation column, so as to make full use of the heat of the vapor phase at the top of the third distillation column and the power consumption of the diaphragm compressor.

[0013] Furthermore, the operating pressures of the first, second, and third distillation columns should decrease sequentially, ensuring that the top vapor temperature of the first distillation column is 10-20°C higher than the bottom reboiling temperature of the second distillation column, and the top vapor temperature of the second distillation column is 10-20°C higher than the bottom reboiling temperature of the third distillation column, so as to ensure sufficient heat transfer temperature difference.

[0014] Furthermore, the first reboiler section uses 1.0-1.5 MPa steam as a heat source, while the first, second, and third condenser reflux units use refrigeration units as cold sources, and the circulating heat transfer oil in the refrigeration units is composed of Freon.

[0015] The present invention also provides an electronic-grade phosphine purification apparatus, comprising the following steps:

[0016] S1. Industrial phosphine is transported to the heavy removal unit via pipeline. It is fed from the middle of the first distillation column. The vapor phase at the top of the column is condensed by the second reboiler and the first condenser and reflux condenser. Part of it is refluxed back into the first distillation column, and part of it enters the second distillation column. The first reboiler causes the material to be vaporized again, and part of it is collected to the light removal unit by controlling the reflux ratio through the first condenser and reflux condenser. High boiling point substances in the first reboiler are discharged and recovered.

[0017] S2. After preliminary purification by the de-weighting unit, the material enters from the middle of the second distillation column. The vapor phase at the top of the column is condensed and refluxed back into the second distillation column by the third reboiler and the second reflux condenser. The second reboiler causes the material to vaporize again, and the second reflux condenser controls the reflux ratio to remove some non-condensable light components. The bottom of the column is collected and sent to the product unit.

[0018] S3. After purification by the light-light unit, the material enters from the middle of the third distillation column. The vapor phase at the top of the column is condensed and refluxed back into the third distillation column by the third condenser and reflux unit. The other part is collected as high-purity phosphine (99.99999%) product. The third reboiler makes the material vaporize again and controls the reflux ratio by the third condenser and reflux unit.

[0019] The electronic-grade phosphine purification system and apparatus provided by this invention have the following beneficial effects:

[0020] 1. By setting up a heavy removal unit, a light removal unit, and a product unit, impurities such as H2O, O2, CO, CO2, H2, C2H2, CH4, SiH4, and C2H4 in industrial phosphine are removed to obtain electronic-grade phosphine.

[0021] 2. By using differential pressure thermal coupling distillation, the heat of the vapor phase at the top of the first distillation column is used as the heat source for the second reboiler, the heat of the vapor phase at the top of the second distillation column is used as the heat source for the third reboiler, and the heat of the vapor phase at the top of the third distillation column is used as part of the heat source for the first reboiler, so as to save the consumption of bottom steam and top electricity, and reduce energy consumption and operating costs.

[0022] 3. By setting up a diaphragm compressor to pressurize the phosphine product to 3.8-4.2 MPa, the phosphine product can be filled at room temperature, reducing the use of liquid nitrogen during the filling process and lowering the safety risks of liquid nitrogen freezing and liquid nitrogen volatilization asphyxiation during operation. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0024] Appendix Figure 1 This is a schematic diagram of the equipment used in the device described in this invention.

[0025] In the diagram: 1-First distillation column; 2-First reboiler A; 3-First reboiler B; 4-First reflux condenser; 5-Second distillation column; 6-Second reboiler; 7-Second reflux condenser; 8-Third distillation column; 9-Third reboiler; 10-Diaphragm compressor; 11-Third reflux condenser; 12-Product filling cylinder; 13-Byproduct tank; 14-Byproduct filling cylinder; 15-Liquid nitrogen cylinder. Detailed Implementation

[0026] like Figure 1 As shown, the apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation includes a heavy removal unit, a light removal unit, and a product unit.

[0027] The deweight removal unit includes a first distillation column 1, which is equipped with a first reflux condenser 4 at the top and a first reboiler 2 at the bottom.

[0028] The light-light-removal unit includes a second distillation column 5, with a second reflux condenser 7 at the top and a second reboiler 6 at the bottom;

[0029] The top of the first distillation column 1 is connected in sequence to the second reboiler 6, the first reflux condenser 4, and the second distillation column 5 via a delivery pipeline;

[0030] The product unit includes a third distillation column 8, which has a third reflux condenser 11 at the top and a third reboiler 9 at the bottom.

[0031] The bottom of the second distillation column 5 is connected to the third distillation column 8 via a delivery pipeline.

[0032] The first reflux condenser 4 is also connected to the upper part of the first distillation column 1.

[0033] The first reboiler includes first reboiler A2 and first reboiler B3.

[0034] The vapor outlet at the top of the second distillation column 5 is connected to the third reboiler 9, which is then connected to the second reflux condenser 7, which is connected to the upper part of the second distillation column 5.

[0035] The bottom of the second distillation column 5 is connected to the second reboiler 6 via a delivery pipeline, and the second reboiler 6 is connected to the lower part of the second distillation column 5.

[0036] The top of the third distillation column 8 is connected to the diaphragm compressor 10, the diaphragm compressor 10 is connected to the first reboiler B3, and the first reboiler B3 is connected to the third condenser reflux unit 11.

[0037] The third condenser reflux unit 11 is partially connected to the upper part of the third distillation column 8 and partially connected to the product filling cylinder area 12.

[0038] The bottom of the third distillation column 8 is connected to the third reboiler 9 and the by-product tank 13 via pipelines. The third reboiler 9 is connected to the lower part of the third distillation column 8.

[0039] The bottom of the first distillation column 1 is connected to the by-product tank 13 via a pipeline.

[0040] The by-product tank 13 is connected to the by-product filling cylinder 14, and a liquid nitrogen cylinder 15 is installed outside the filling cylinder 14.

[0041] S1. Industrial phosphine is transported to the de-weighting unit through a pipeline. It is fed from the middle of the first distillation column. The vapor phase at the top of the column is condensed by the second reboiler and the first condenser and refluxer. Part of it is returned to the first distillation column and part of it enters the second distillation column.

[0042] S2. After preliminary purification by the deweighting unit, the material enters from the middle of the second distillation column. The vapor phase at the top of the column is condensed and refluxed back into the second distillation column by the third reboiler and the second condenser and reflux unit. The bottom of the column is collected and sent to the product unit.

[0043] S3. After purification by the light-removal unit, the material enters from the middle of the third distillation column. The top gas phase is condensed and refluxed back into the third distillation column by the third condenser, and the other part is collected as electronic-grade phosphine product.

[0044] The physicochemical properties of industrial phosphine are as follows: phosphine content 99.9%, water 54 ppm, arsine 520 ppm, oxygen 210 ppm, nitrogen 520 ppm, carbon dioxide 72 ppm, methane 65 ppm, and ethane 54 ppm.

[0045] The operating pressures of the first, second, and third distillation columns decrease sequentially, ensuring that the top vapor temperature of the first distillation column is 10-20°C higher than the bottom reboiling temperature of the second distillation column, and the top vapor temperature of the second distillation column is 10-20°C higher than the bottom reboiling temperature of the third distillation column.

[0046] The pressure inside the first distillation column is 2.00-2.5 MPa, and the temperature is -5 to 0℃, which causes the material inside the first distillation column to vaporize.

[0047] All the vaporized material in the first distillation column is used as the heat source for the reboiler of the second distillation column. The gas-liquid mixture after heat exchange enters the first condenser reflux condenser, and the reflux ratio is controlled by the first condenser reflux condenser. 6-8% is collected to the second distillation column, and the remainder is returned to the first distillation column.

[0048] The pressure inside the second distillation column is 1.3-1.8 MPa and the temperature is -15 to -10℃, which causes the material inside the second distillation column to vaporize.

[0049] All the vaporized material in the second distillation column is used as the heat source for the reboiler of the third distillation column. The gas-liquid mixture after heat exchange enters the second condenser and reflux condenser. After condensation, the liquid phase is all returned to the second distillation column, and the non-condensable gas is discharged to the tail gas.

[0050] The pressure inside the third distillation column is 0.8-1.1 MPa and the temperature is -28 to -23°C, which causes the material inside the third distillation column to vaporize.

[0051] The vaporized material in the third distillation column passes through the third condenser and reflux condenser. The reflux ratio is controlled by the third condenser and reflux condenser. 6-8% is taken out to obtain electronic grade phosphine, and the remainder is returned to the third distillation column.

[0052] The product obtained in this embodiment has a phosphine grade of 7N, and the content of key impurities is less than 50 ppb for water, less than 10 ppb for arsine, less than 10 ppb for carbon dioxide, less than 10 ppb for methane, and less than 10 ppb for ethane.

[0053] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation, characterized in that, The device includes a heavy-weight removal unit, a light-weight removal unit, and a product unit; The deweight removal unit includes a first distillation column, which has a first reflux condenser at the top and a first reboiler at the bottom. The light-light-removal unit includes a second distillation column, which has a second reflux condenser at the top and a second reboiler at the bottom. The top of the first distillation column is connected in sequence to the second reboiler, the first reflux condenser, and the second distillation column via a delivery pipeline. The product unit includes a third distillation column, which has a third reflux condenser at the top and a third reboiler at the bottom. The bottom of the second distillation column is connected to the third distillation column via a delivery pipeline.

2. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 1, characterized in that, The first reflux condenser is also connected to the upper part of the first distillation column.

3. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 1, characterized in that, The first reboiler includes first reboiler A and first reboiler B.

4. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 1, characterized in that, The vapor outlet at the top of the second distillation column is connected to the third reboiler, which is then connected to the second reflux condenser, which is connected to the upper part of the second distillation column.

5. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 1, characterized in that, The bottom of the second distillation column is connected to the second reboiler via a delivery pipeline, and the second reboiler is connected to the lower part of the second distillation column.

6. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 2, characterized in that, The top of the third distillation column is connected to a diaphragm compressor, which is connected to the first reboiler B, which is connected to the third condenser reflux unit.

7. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 6, characterized in that, The third condenser reflux unit is partly connected to the upper part of the third distillation column and partly connected to the product filling cylinder area.

8. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 1, characterized in that, The bottom of the third distillation column is connected to the third reboiler and the by-product tank via pipelines. The third reboiler is connected to the lower part of the third distillation column.

9. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 1, characterized in that, The bottom of the first distillation column is connected to the by-product tank via a pipeline.

10. The apparatus for producing ultrapure phosphine by differential pressure thermal coupling distillation according to claim 8, characterized in that, The by-product tank is connected to the by-product filling cylinder, and a liquid nitrogen cylinder is installed outside the filling cylinder.

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