An apparatus for purifying sulfur tetrafluoride by multistage rectification

Abstract

The utility model provides a kind of device of multistage rectification purification sulfur tetrafluoride, can realize rectification purification of sulfur hexafluoride while rectification purification sulfur tetrafluoride, the device further includes heavy component column, the upper middle part of heavy component column is equipped with secondary feed inlet, its bottom is equipped with secondary liquid outlet, its upper part is equipped with secondary gas outlet, secondary condenser is installed on the upper part of heavy component column, main liquid outlet is communicated with secondary feed inlet by intermediate pipe, material pump is equipped on intermediate pipe, heater is installed on intermediate pipe between material pump and heavy component column, main gas outlet is communicated with sulfur tetrafluoride storage tank by main collecting pipe, secondary gas outlet is communicated with sulfur hexafluoride storage tank by secondary collecting pipe, secondary liquid outlet is communicated with residual liquid tank by residual liquid collecting pipe, improve economic value, using gaseous material precooling treatment, can improve the promotion efficiency of sulfur tetrafluoride.

Description

Technical Field

[0001] This utility model relates to the field of sulfur tetrafluoride preparation technology, and in particular to an apparatus for purifying sulfur tetrafluoride by multi-stage distillation. Background Technology

[0002] Sulfur tetrafluoride (SF4) is an important inorganic compound with unique value in industrial and scientific research fields. As a fluoride of sulfur, its molecular structure is a deformed tetrahedral configuration, with the central sulfur atom and four fluorine atoms covalently bonded together, exhibiting high reactivity. Since the mid-20th century, sulfur tetrafluoride has been mainly used as a highly efficient fluorinating reagent in organic synthesis, capable of selectively converting functional groups such as hydroxyl and carbonyl groups into fluorinated derivatives.

[0003] In materials science, sulfur tetrafluoride (SF) is used in etching processes during semiconductor manufacturing due to its unique electronic structure. However, its poor thermal stability and tendency to hydrolyze in humid air to produce toxic hydrogen fluoride and sulfur dioxide limit its large-scale application. In recent years, researchers have discovered the potential of SF in preparing novel fluoropolymers, which exhibit excellent chemical resistance and thermal stability.

[0004] During the production of sulfur tetrafluoride, a certain amount of sulfur hexafluoride is often generated simultaneously. Sulfur hexafluoride is also an important inorganic chemical raw material. Distillation separation and purification of sulfur hexafluoride during the refining and purification process can maximize its economic value. Summary of the Invention

[0005] In view of the above situation and to overcome the defects of the prior art, the purpose of this utility model is to provide a multi-stage distillation purification device for sulfur tetrafluoride, which can simultaneously purify sulfur hexafluoride by distillation, with high purification efficiency.

[0006] A multi-stage distillation apparatus for purifying sulfur tetrafluoride includes a main distillation column with a main gas outlet at the top, a main feed inlet in the middle, and a main liquid outlet at the bottom. A main condenser is installed on the upper part of the main distillation column. The apparatus also includes a secondary fraction column with a secondary feed inlet in the upper middle part, a secondary liquid outlet at the bottom, and a secondary gas outlet at the top. A secondary condenser is installed on the upper part of the secondary fraction column. The main liquid outlet is connected to the secondary feed inlet via an intermediate pipe. A material pump is installed on the intermediate pipe. A heater is installed on the intermediate pipe between the material pump and the secondary fraction column. The main gas outlet is connected to a sulfur tetrafluoride storage tank via a main collection pipe. The secondary gas outlet is connected to a sulfur hexafluoride storage tank via a secondary collection pipe. The secondary liquid outlet is connected to a residual liquid tank via a residual liquid collection pipe. The main feed inlet is connected to a main feed pipe.

[0007] Preferably, the residual liquid collection pipe is equipped with a reflux pipe via a three-way valve, the bottom of the recombinant column is provided with a reflux inlet, the free end of the reflux pipe is connected to the reflux inlet, a reflux pump is installed on the reflux pipe, and a reboiler is installed on the reflux pipe between the reflux pump and the reflux inlet.

[0008] Preferably, a precooler is installed on the main feed pipe, and an atomizing nozzle facing the interior of the main distillation column is installed on the main feed inlet.

[0009] Preferably, the inner wall of the main distillation column is coated with an Al2O3-TiO2 composite coating.

[0010] Preferably, the sulfur tetrafluoride storage tank adopts a double-layer vacuum insulation structure and is equipped with a temperature sensor.

[0011] The beneficial effects of this invention are as follows: Since the material contains two useful components, sulfur tetrafluoride and sulfur hexafluoride, while sulfur tetrafluoride is purified by distillation, sulfur hexafluoride can also be separated, purified and utilized, thus improving economic value. The pre-cooling treatment of the gaseous material can improve the efficiency of sulfur tetrafluoride extraction. Attached Figure Description

[0012] Figure 1 This is a flowchart illustrating the process of this utility model. Detailed Implementation

[0013] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0014] Depend on Figure 1 Provided is a multi-stage distillation apparatus for purifying sulfur tetrafluoride, comprising a main distillation column 1, with a main gas outlet 2 at the top, a main feed inlet 3 in the middle, and a main liquid outlet 4 at the bottom. A main condenser 5 is installed on the upper part of the main distillation column 1, providing a cooling source for the distillation process of the main distillation column 1. It also includes a heavy fraction column 6, with a secondary feed inlet 7 in the upper middle part, a secondary liquid outlet 8 at the bottom, and a secondary gas outlet 9 at the top. A secondary condenser 10 is installed on the upper part of the heavy fraction column 6, providing cooling for the distillation process of the heavy fraction column 6. The main liquid outlet 4 is connected to the secondary feed inlet 7 via an intermediate pipe 11. A material pump 12 is installed on the intermediate pipe 11, and a heater 13 is installed on the intermediate pipe 11 between the material pump 12 and the heavy fractionation tower 6. The main gas outlet 2 is connected to a sulfur tetrafluoride storage tank 16 via a main collection pipe 15. The secondary gas outlet 9 is connected to a sulfur hexafluoride storage tank 18 via a secondary collection pipe 17. The secondary liquid outlet 8 is connected to a residual liquid tank 19 via a residual liquid collection pipe 23. The residual liquid tank 19 collects and stores the liquid residue for further processing to prevent environmental pollution. The main feed inlet 3 is connected to a main feed pipe 20.

[0015] The main condenser 5 provides a cold source for the main distillation column 1. It adopts a refrigeration unit mode that combines a screw compressor and a plate-fin heat exchanger, which can provide a low temperature below -80 degrees and can stably ensure the system operates stably in the temperature range of -50 degrees to -80 degrees.

[0016] The feed material entering through the main feed pipe 20 contains sulfur tetrafluoride, sulfur hexafluoride, and hydrogen fluoride. The feed material enters the main distillation column 1. Under the action of the packing material in the main distillation column 1, sulfur tetrafluoride remains in a gaseous state and rises, while other components become liquid and begin to descend. Then, the sulfur tetrafluoride enters the sulfur tetrafluoride storage tank 16 through the main outlet 2 and the main collection pipe 15. The separated heavy fraction is divided into a second product, which enters the heavy fraction column 6 through the intermediate pipe 11. After distillation in the heavy fraction column, sulfur hexafluoride rises in a gaseous state and then enters the sulfur hexafluoride storage tank through the secondary outlet 9. The material pump 12 pressurizes and transports the second product from the main distillation column 1 to the heater 13. Under the heating action of the heater 13, the second product can be vaporized and enters the heavy fraction column 6 in a gaseous state for further distillation and purification of the sulfur hexafluoride.

[0017] In this embodiment, a main liquefaction condenser is installed on the main collection pipe 15, and a secondary liquefaction condenser is installed on the secondary collection pipe 17. The main liquefaction condenser liquefies sulfur tetrafluoride into a liquid state, and the secondary liquefaction condenser liquefies sulfur hexafluoride into a liquid state, thus facilitating the collection and storage of sulfur tetrafluoride and sulfur hexafluoride.

[0018] In this embodiment, the residual liquid collection pipe 23 is connected to a reflux pipe 21 via a three-way valve. The bottom of the heavy fractionation tower 6 is provided with a reflux inlet. The free end of the reflux pipe 21 is connected to the reflux inlet. A reflux pump 22 is installed on the reflux pipe 21, and a reboiler 24 is installed on the reflux pipe 21 between the reflux pump 22 and the reflux inlet. A three-way valve is installed on the collection pipe, with one channel connected to the main outlet 4, one channel connected to the heavy fractionation tower 6, and the other channel connected to the reboiler 24. When repeated purification of the material is required, the reboiler 24 is connected for circulating purification of the material. After distillation purification, the other channel is connected for residual liquid collection.

[0019] A precooler 25 is installed on the main feed pipe 20, and an atomizing nozzle facing the interior of the main distillation column 1 is installed on the main feed inlet 3. The material passing through the precooler 25 exists in both gas and liquid phases. The atomizing nozzle is a dual-fluid nozzle, capable of spraying the material into the main distillation column 1, where it is separated and purified by the packing material. The material is precooled and liquefied by the precooler 25 before entering the main distillation column 1, maintaining a lower temperature, which effectively improves the distillation efficiency of the material, resulting in a faster distillation process in the main distillation column 1.

[0020] In this implementation example, because fluorides and sulfides are highly corrosive, the inner wall of the main distillation column 1 is coated with an Al2O3-TiO2 composite coating. Using a plasma-sprayed Al2O3-TiO2 composite coating on the inner wall of the main distillation column 1 provides better corrosion resistance, reduces the erosion of equipment by HF and sulfides at high temperatures, and extends the service life of the equipment.

[0021] In this embodiment, the sulfur tetrafluoride storage tank is improved. The sulfur tetrafluoride storage tank 16 adopts a double-layer vacuum insulation structure and is equipped with a temperature sensor. The main distillation column 1 is made of 316L stainless steel. The double-layer vacuum structure reduces heat exchange with the outside, making the low-temperature storage of sulfur tetrafluoride more stable and reliable.

[0022] The beneficial effects of this invention are as follows: Since the material contains two useful components, sulfur tetrafluoride and sulfur hexafluoride, while sulfur tetrafluoride is purified by distillation, sulfur hexafluoride can also be separated, purified and utilized, thus improving economic value. The pre-cooling treatment of the gaseous material can improve the efficiency of sulfur tetrafluoride extraction.

[0023] The embodiments described above are not intended to limit the scope of the present invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the inventive concept should be included within the scope of protection defined by the claims of the present invention.

Claims

1. A multi-stage distillation apparatus for purifying sulfur tetrafluoride, comprising a main distillation column (1), wherein the main distillation column (1) has a main gas outlet (2) at the top, a main feed inlet (3) in the middle, and a main liquid outlet (4) at the bottom, and a main condenser (5) is installed on the upper part of the main distillation column (1), characterized in that, It also includes a secondary feed inlet (7) in the middle of the upper part of the secondary feed inlet (6), a secondary liquid outlet (8) at the bottom of the secondary feed inlet (8), a secondary gas outlet (9) at the top of the secondary feed inlet (6), a secondary condenser (10) installed on the upper part of the secondary feed inlet (6), the main liquid outlet (4) being connected to the secondary feed inlet (7) through an intermediate pipe (11), a material pump (12) being installed on the intermediate pipe (11), a heater (13) being installed on the intermediate pipe (11) between the material pump (12) and the secondary feed inlet (6), the main gas outlet (2) being connected to a sulfur tetrafluoride storage tank (16) through a main collection pipe (15), the secondary gas outlet (9) being connected to a sulfur hexafluoride storage tank (18) through a secondary collection pipe (17), the secondary liquid outlet (8) being connected to a residual liquid tank (19) through a residual liquid collection pipe (23), and the main feed inlet (3) being connected to a main feed pipe (20).

2. The apparatus for multi-stage distillation purification of sulfur tetrafluoride according to claim 1, characterized in that, The main collection pipe (15) is equipped with a main liquefaction condenser, and the secondary collection pipe (17) is equipped with a secondary liquefaction condenser.

3. The apparatus for multi-stage distillation purification of sulfur tetrafluoride according to claim 1 or 2, characterized in that, The residual liquid collection pipe (23) is equipped with a reflux pipe (21) through a three-way valve. The bottom of the recombinant column (6) is provided with a reflux inlet. The free end of the reflux pipe (21) is connected to the reflux inlet. A reflux pump (22) is installed on the reflux pipe (21). A reboiler (24) located between the reflux pump (22) and the reflux inlet is installed on the reflux pipe (21).

4. The apparatus for multi-stage distillation purification of sulfur tetrafluoride according to claim 1, characterized in that, A precooler (25) is installed on the main feed pipe (20), and an atomizing nozzle facing the interior of the main distillation column (1) is installed on the main feed port (3).

5. The apparatus for multi-stage distillation purification of sulfur tetrafluoride according to claim 1, characterized in that, Therefore, the inner wall of the main distillation column (1) is coated with an Al2O3-TiO2 composite coating.

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