Device for purifying tetramethylsilane and method for recovering tetramethylsilane in steel cylinder

Abstract

The invention discloses a purification device of tetramethylsilane and a recovery method of tetramethylsilane in a steel cylinder. The tetramethylsilane purification device comprises a vaporizer, an adsorption column, a filter, an intermediate tank and a product tank. The vaporizer is connected with the steel cylinder and used for vaporizing tetramethylsilane in the steel cylinder, and a plurality of sample outlets and sample inlets are formed in the steel cylinder; one end of the adsorption column is connected with the vaporizer, and the adsorption column is used for adsorbing gaseous impurities in tetramethylsilane; the filter is connected with the other end of the adsorption column and is used for filtering particulate impurities in tetramethylsilane; the intermediate tank is communicated with the filter, can be communicated with the steel cylinder and is used for temporarily storing filtered tetramethylsilane; and the product tank is communicated with the intermediate tank and is used for storing purified tetramethylsilane. The purification device disclosed by the invention is simple in structure, and can be connected through a simple pipeline, so that the recovery of raw materials in the steel cylinder and the flushing and replacement of the steel cylinder can be completed on a production site, the production efficiency is improved, and the purification cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical purification and separation, and specifically relates to a tetramethylsilane purification device, a method for recovering tetramethylsilane in a steel cylinder, and a method for treating contaminated steel cylinders. Background Art

[0002] 4MS, Chinese name tetramethylsilane, is an important organic silicon material, which is widely used in medicine, aerospace construction and mechanical materials. Ultra-high purity (mass fraction ≥ 99.99%) 4MS can be used as a precursor for chemical vapor deposition (CVD) or plasma enhanced chemical vapor deposition (PECVD) in the electronics industry to prepare high-quality silicon carbide films.

[0003] The packaging container of 4MS is generally a metal precursor cylinder, which usually has multiple sample inlets and outlets and a liquid level gauge interface. In the production process, tetramethylsilane is generally filled into the cylinder in liquid form, and helium or nitrogen with a certain pressure is filled into the upper part of the cylinder as a means of maintaining pressure. At the same time, this pressure can also be used as a power source for the initial raw material transportation. When the client uses the precursor, it will be connected to the chemical supply system and transported to the corresponding process end through a clean pipeline. In order to ensure the use of the semiconductor process section, a variety of chemicals in the cylinder, including tetramethylsilane and ethyl orthosilicate, will not be completely used. When returning to the supplier, there is often a certain amount of product in the cylinder. Although these residual products do not affect the filling and product quality in the short term, over time, the heavy component impurities and particulate matter in the cylinder will accumulate over time, and eventually the cylinder will become a contaminated cylinder, which needs to be thoroughly treated before it can be restored to use. The residual products in the bottle are often high-value-added semiconductor chemical materials that need to be re-purified.

[0004] For tetramethylsilane, the current mainstream purification process is mainly energy-intensive distillation + adsorption. Due to the special properties of tetramethylsilane, it will produce azeotropy with more organic matter, affecting the distillation effect.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a tetramethylsilane purification device, a method for recovering tetramethylsilane in a steel cylinder and a method for treating contaminated steel cylinders, which can fully recover tetramethylsilane and clean the steel cylinders.

[0007] In order to achieve the above-mentioned purpose, a specific embodiment of the present invention provides a tetramethylsilane purification device, which includes a vaporizer, an adsorption column, a filter, an intermediate tank and a product tank. The vaporizer is connected to a steel cylinder, and is used to vaporize the tetramethylsilane in the steel cylinder, and the steel cylinder is provided with a plurality of sample outlets and sample inlets; one end of the adsorption column is connected to the vaporizer, and is used to adsorb gaseous impurities in the tetramethylsilane; the filter is connected to the other end of the adsorption column, and is used to filter particulate impurities in the tetramethylsilane; the intermediate tank is connected to the filter and can be connected to the steel cylinder, and is used to temporarily store the filtered tetramethylsilane; the product tank is connected to the intermediate tank, and is used to store the purified tetramethylsilane.

[0008] In one or more embodiments of the present invention, the product tank can be connected to a cylinder connected to the vaporizer.

[0009] In one or more embodiments of the present invention, the adsorbent in the adsorption column is selected from one or more of 13X, ZSM-5, 4A and mordenite.

[0010] In one or more embodiments of the present invention, the height-to-diameter ratio of the adsorption column is between (10-20):1.

[0011] Compared with the prior art, the purification device of the present invention has a simple structure and can complete the recovery of raw materials in steel cylinders and the flushing and replacement of steel cylinders at the production site through simple pipeline connections, thereby improving production efficiency and reducing purification costs.

[0012] Another specific embodiment of the present invention provides a method for recovering tetramethylsilane in a steel cylinder, which comprises: filling a certain amount of nitrogen into the steel cylinder; pressing the tetramethylsilane in the steel cylinder into a vaporizer for vaporization and conveying it to an adsorption column for adsorption treatment; conveying the tetramethylsilane after adsorption treatment to a filter for filtration treatment; conveying the tetramethylsilane after filtration treatment into an intermediate tank and inspecting the tetramethylsilane in the intermediate tank, and if the inspection is qualified, conveying the tetramethylsilane in the intermediate tank to a product tank; if the inspection is unqualified, repeating the above steps until the tetramethylsilane passes the inspection.

[0013] In one or more embodiments of the present invention, the vaporization temperature of the vaporizer is between 35°C and 40°C.

[0014] In one or more embodiments of the present invention, the adsorption temperature of the adsorption column is between 35°C and 45°C.

[0015] In one or more embodiments of the present invention, the space velocity of the adsorption column is between 30h -1 -50h -1 .

[0016] Compared with the prior art, the method for recovering tetramethylsilane in a steel cylinder of the present invention simplifies the purification steps by utilizing the above-mentioned purification device, has a simple method, and can effectively recover tetramethylsilane in the contaminated steel cylinder, thereby reducing waste and lowering purification costs.

[0017] Another specific embodiment of the present invention provides a method for treating a contaminated steel cylinder, which includes: filling the contaminated steel cylinder with tetramethylsilane of qualified purity and a certain amount of nitrogen; pressing the tetramethylsilane in the contaminated steel cylinder into a vaporizer for vaporization and conveying it to an adsorption column for adsorption treatment; conveying the tetramethylsilane after adsorption treatment to a filter for filtration treatment; conveying the tetramethylsilane after filtration treatment into an intermediate tank and inspecting the tetramethylsilane in the intermediate tank, and if the inspection is qualified, conveying the tetramethylsilane in the intermediate tank to a product tank; if the inspection is unqualified, repeating the above steps until the tetramethylsilane passes the inspection.

[0018] In one or more embodiments of the present invention, the qualified tetramethylsilane is filled into the contaminated cylinder from a product tank or a non-contaminated cylinder.

[0019] Compared with the prior art, the method for treating contaminated steel cylinders of the present invention can effectively treat the contaminated steel cylinders by utilizing a purification device, and combined with a method for recovering tetramethylsilane, the contaminated steel cylinders can be cleaned while recovering tetramethylsilane, thereby reducing the cost of tetramethylsilane recovery and steel cylinder cleaning and simplifying the related operating steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 Schematic diagram of a purification device in one embodiment of the present invention.

[0022] Description of main reference numerals:

[0023] 1-vaporizer, 2-adsorption column, 3-filter, 4-intermediate tank, 5-product tank, 6-steel cylinder. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] like Figure 1 As shown, a purification device in one embodiment of the present invention includes a vaporizer 1, an adsorption column 2, a filter 3, an intermediate tank 4 and a product tank 5. The vaporizer 1 is connected to the steel cylinder 6 and is used to vaporize the tetramethylsilane in the steel cylinder 6. The steel cylinder 6 is provided with a plurality of sample outlets and sample inlets. One end of the adsorption column 2 is connected to the vaporizer 1 and is used to adsorb impurities in the tetramethylsilane. The filter 3 is connected to the other end of the adsorption column 2 and is used to filter particulate impurities in the tetramethylsilane. The intermediate tank 4 is connected to the filter 3 and can be connected to the steel cylinder 6 for temporarily storing the filtered tetramethylsilane. The product tank 5 is connected to the intermediate tank 4 and is used to store the purified tetramethylsilane.

[0026] The working principle of the purification device is as follows: the steel cylinder 6 with residual tetramethylsilane is connected to the vaporizer 1, and then the tetramethylsilane in the steel cylinder 6 is transported into the vaporizer 1 for vaporization. The vaporized tetramethylsilane is transported into the adsorption column 2 to remove gaseous impurities in the tetramethylsilane, and then the tetramethylsilane is transported into the filter 3 to filter the particulate impurities in the tetramethylsilane. The filtered tetramethylsilane is transported to the intermediate tank 4 to wait for inspection. If the inspection is qualified, the tetramethylsilane in the intermediate tank 4 can be transported to the product tank 5 to wait for filling. If the inspection fails, the tetramethylsilane is returned to the steel cylinder 6 and then re-vaporized, adsorbed and filtered until it passes the inspection.

[0027] In one embodiment, the product tank 5 can be connected to the steel cylinder 6 connected to the vaporizer 1 so that the qualified product stored in the product tank 5 can be directly filled into the steel cylinder 6.

[0028] In addition, a mass flow controller (MFC) may be provided between the cylinder 6 and the vaporizer 1 to control the amount of tetramethylsilane entering the vaporizer 1 .

[0029] In one embodiment, the adsorbent in the adsorption column 2 can be selected from one or more of 13X, ZSM-5, XX and XX. For example, the adsorbent can be only 13X, or a mixture of 13X and ZSM-5. The height-to-diameter ratio of the adsorption column 2 is between (10-20): 1 to ensure that impurities in the product can be fully adsorbed in the adsorption column 2.

[0030] In summary, the purification device of the present invention has a simple structure and can complete the recovery of raw materials in the steel cylinder 6 and the flushing and replacement of the steel cylinder 6 at the production site through simple pipeline connection, thereby improving production efficiency and reducing purification costs.

[0031] A method for recovering tetramethylsilane in a steel cylinder in another embodiment of the present invention comprises steps S1-S4.

[0032] S1: Fill a certain amount of nitrogen into the contaminated steel cylinder 6.

[0033] Specifically, in step S1 , the steel cylinder 6 is connected to the vaporizer 1 and 0.1 MPa-0.3 MPa of nitrogen is charged into the steel cylinder 6 to provide pressure to press out the tetramethylsilane in the steel cylinder 6 .

[0034] S2: The tetramethylsilane in the cylinder 6 is pressed into the vaporizer 1 for vaporization and transported to the adsorption column 2 for adsorption treatment.

[0035] Specifically, in step S2, tetramethylsilane in cylinder 6 is pressed into vaporizer 1 through MFC for vaporization. The vaporization temperature of the vaporization chamber is set at 35°C-40°C. Then, the vaporized tetramethylsilane is transported to adsorption column 2 for adsorption, and the adsorption temperature of adsorption column 2 is controlled at 35°C-45°C. The air velocity of adsorption column 2 is controlled for 30h. -1 -50h -1 .

[0036] S3: The tetramethylsilane after the adsorption treatment is transported to the filter 3 for filtration treatment.

[0037] Specifically, in step S3, the tetramethylsilane after the adsorption treatment is transported to the filter 3 for filtration treatment. The filtration accuracy of the filter 3 is 3 nm.

[0038] S4: The filtered tetramethylsilane is transported into the intermediate tank 4 and the tetramethylsilane in the intermediate tank 4 is inspected. If the inspection is qualified, the tetramethylsilane in the intermediate tank 4 is transported to the product tank 5; if the inspection is unqualified, the above steps are repeated until the tetramethylsilane passes the inspection.

[0039] Specifically, in step S4, the tetramethylsilane after filtration is transported into the intermediate tank 4 and the tetramethylsilane in the intermediate tank 4 is tested. The intermediate tank 4 needs to control the temperature and cool the gaseous tetramethylsilane to 15°C. The tetramethylsilane in the intermediate tank 4 is sampled and analyzed. After confirming that the purity meets the requirements, the tetramethylsilane in the intermediate tank 4 is transported into the product tank 5 by pressure. If the inspection fails, it is pressed back to the contaminated bottle by pressure, and re-adsorbed and filtered until the purity meets the requirements.

[0040] A method for treating a contaminated steel cylinder 6 in another embodiment of the present invention includes steps S11 - S41 .

[0041] S11: Fill the contaminated cylinder 6 with tetramethylsilane of qualified purity and a certain amount of nitrogen.

[0042] Specifically, in step S11, the contaminated steel cylinder 6 is connected to the vaporizer 1 and tetramethylsilane with qualified purity and 0.1MPa-0.3MPa nitrogen are charged into the contaminated steel cylinder 6 to provide a certain gas pressure to fill the steel cylinder 6. The amount of tetramethylsilane with qualified purity entering the contaminated steel cylinder 6 is measured by weight and cannot exceed 80% of the weight that the connected contaminated steel cylinder 6 can contain. Tetramethylsilane with qualified purity can be provided by the product tank 5 connected to the contaminated steel cylinder 6 or the non-contaminated steel cylinder 6.

[0043] S21: The tetramethylsilane in the contaminated cylinder 6 is pressed into the vaporizer 1 for vaporization and transported to the adsorption column 2 for adsorption treatment.

[0044] Specifically, in step S21, the tetramethylsilane in the contaminated cylinder 6 is pressed into the vaporizer 1 through the MFC for vaporization. The vaporization temperature of the vaporization chamber is set at 35°C-40°C. Then, the vaporized tetramethylsilane is transported to the adsorption column 2 for adsorption, and the adsorption temperature of the adsorption column 2 is controlled at 35°C-45°C. The air velocity of the adsorption column 2 is controlled at 30h. -1 -50h -1 .

[0045] S31: The tetramethylsilane after the adsorption treatment is transported to the filter 3 for filtration treatment.

[0046] Specifically, in step S31, the tetramethylsilane after the adsorption treatment is transported to the filter 3 for filtration treatment. The filtration accuracy of the filter 3 is 3 nm.

[0047] S41: The tetramethylsilane after filtration is transported into the intermediate tank 4 and the tetramethylsilane in the intermediate tank 4 is inspected. If the inspection is qualified, the tetramethylsilane in the intermediate tank 4 is transported to the product tank 5; if the inspection is unqualified, the above steps are repeated until the tetramethylsilane passes the inspection.

[0048] Specifically, in step S41, the tetramethylsilane after filtration is transported into the intermediate tank 4 and the tetramethylsilane in the intermediate tank 4 is tested. The intermediate tank 4 needs to control the temperature and cool the gaseous tetramethylsilane to 15°C. The tetramethylsilane in the intermediate tank 4 is sampled and analyzed. After confirming that the purity meets the requirements, the tetramethylsilane in the intermediate tank 4 is transported into the product tank 5 by pressure. If the inspection fails, it is pressed back to the contaminated bottle by pressure, and re-adsorbed and filtered until the purity meets the requirements.

[0049] Since the contaminated steel cylinder 6 becomes a non-contaminated steel cylinder 6 after the above steps, the product tank 5 connected thereto can also directly fill the tetramethylsilane of qualified purity into the steel cylinder 6, thereby realizing the treatment and filling of the contaminated steel cylinder 6 at the same time, simplifying the operation steps and processes. Moreover, the treatment method of the contaminated steel cylinder 6 can be combined with the recovery method of the tetramethylsilane in the contaminated steel cylinder 6, and the cleaning of the contaminated steel cylinder 6 can be realized after the recovery of the tetramethylsilane is completed.

[0050] In summary, the method for recovering tetramethylsilane in the steel cylinder 6 of the present invention simplifies the purification steps by using the above-mentioned purification device, and the method is simple, and can effectively recover tetramethylsilane in the contaminated steel cylinder 6, thereby reducing waste and reducing purification costs. The method for treating the contaminated steel cylinder 6 of the present invention can effectively treat the contaminated steel cylinder 6 by using the above-mentioned purification device, and combined with the above-mentioned method for recovering tetramethylsilane, it can realize the cleaning of the contaminated steel cylinder 6 while realizing the recovery of tetramethylsilane, thereby reducing the cost of recovering tetramethylsilane and cleaning of the steel cylinder 6, and simplifying the relevant operation steps.

[0051] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0052] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A tetramethylsilane purification device, characterized in that, include: A vaporizer connected to the steel cylinder and used to vaporize the tetramethylsilane in the steel cylinder, wherein the steel cylinder is provided with a plurality of sample outlets and sample inlets; an adsorption column, one end of which is connected to the vaporizer and is used to adsorb gaseous impurities in the tetramethylsilane; A filter connected to the other end of the adsorption column and used to filter particulate impurities in the tetramethylsilane; An intermediate tank, which is in communication with the filter and can be in communication with the steel cylinder, and is used for temporarily storing the filtered tetramethylsilane; The product tank is connected to the intermediate tank and is used to store purified tetramethylsilane.

2. The tetramethylsilane purification device according to claim 1, characterized in that: The product tank can communicate with a cylinder connected to the vaporizer.

3. The tetramethylsilane purification device according to claim 1, characterized in that: The adsorbent in the adsorption column is selected from one or more of 13X, ZSM-5, 4A and mordenite.

4. The tetramethylsilane purification device according to claim 1, characterized in that: The height-to-diameter ratio of the adsorption column is between (10-20):

1.

5. A method for recovering tetramethylsilane in a steel cylinder, characterized in that: include: Fill a certain amount of nitrogen into the cylinder; The tetramethylsilane in the cylinder is pressed into a vaporizer for vaporization and transported to an adsorption column for adsorption treatment; The adsorbed tetramethylsilane is transported to a filter for filtration; The filtered tetramethylsilane is transported to the intermediate tank and the tetramethylsilane in the intermediate tank is inspected. If the inspection is qualified, the tetramethylsilane in the intermediate tank is transported to the product tank; if the inspection is unqualified, the above steps are repeated until the tetramethylsilane passes the inspection.

6. The method for recovering tetramethylsilane in a steel cylinder according to claim 5, characterized in that: The vaporization temperature of the vaporizer is between 35°C and 40°C.

7. The method for recovering tetramethylsilane in a steel cylinder according to claim 5, characterized in that: The adsorption temperature of the adsorption column is between 35°C and 45°C.

8. The method for recovering tetramethylsilane in a steel cylinder according to claim 5, characterized in that: The space velocity of the adsorption column is between 30h -1 -50h -1 .

9. A method for treating contaminated steel cylinders, characterized in that: include: Fill the contaminated cylinder with tetramethylsilane of qualified purity and a certain amount of nitrogen; The tetramethylsilane in the contaminated cylinder is pressed into a vaporizer for vaporization and transported to an adsorption column for adsorption treatment; The adsorbed tetramethylsilane is transported to a filter for filtration; The filtered tetramethylsilane is transported to the intermediate tank and the tetramethylsilane in the intermediate tank is inspected. If the inspection is qualified, the tetramethylsilane in the intermediate tank is transported to the product tank; if the inspection is unqualified, the above steps are repeated until the tetramethylsilane passes the inspection.

10. The method for treating contaminated steel cylinders according to claim 9, characterized in that: The qualified tetramethylsilane is filled into the contaminated cylinder from a product tank or a non-contaminated cylinder.

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