CN115040975A - Device for purifying silicon tetrachloride - Google Patents
Device for purifying silicon tetrachloride Download PDFInfo
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- CN115040975A CN115040975A CN202210528352.9A CN202210528352A CN115040975A CN 115040975 A CN115040975 A CN 115040975A CN 202210528352 A CN202210528352 A CN 202210528352A CN 115040975 A CN115040975 A CN 115040975A
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- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
- B01D53/0407—Constructional details of adsorbing systems
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- C01B33/1071—Tetrachloride, trichlorosilane or silicochloroform, dichlorosilane, monochlorosilane or mixtures thereof
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Abstract
The invention discloses a device for purifying silicon tetrachloride, which comprises a purification device, a monitoring system and a pipeline assembly, wherein the purification device comprises a purification device body and a pipeline assembly; the purification device comprises a shell, an air inlet pipeline and an air outlet pipeline, wherein the shell is internally provided with a long strip-shaped cavity; the front section of the strip-shaped cavity is a hydrolysis area, and the rear section of the strip-shaped cavity is a drying area; the air inlet pipeline is communicated with the front end of the hydrolysis area, and the air outlet pipeline is communicated with the rear end of the drying area; the gas outlet pipeline is communicated with a monitoring system; the hydrolysis area is uniformly distributed with an adsorbent which is a crystalline hydrate, and the drying area is uniformly distributed with a drying agent; the drying agent is silica gel or molecular sieve; and the pipeline component comprises an unqualified STC pipeline and a qualified STC pipeline, the qualified STC pipeline is communicated with the monitoring system, and two ends of the unqualified STC pipeline are respectively communicated with the monitoring system and the air inlet pipeline. According to the invention, the crystal water in the crystal hydrate is used for replacing liquid water to carry out hydrolysis reaction, so that safe and effective impurity removal on STC is realized.
Description
Technical Field
The invention relates to the technical field of polycrystalline silicon production, in particular to a device for purifying silicon tetrachloride.
Background
The improved Siemens process is a preparation process for producing polycrystalline silicon, and the principle is that high-purity hydrogen is used for reducing high-purity Trichlorosilane (TCS) on a high-purity silicon core at about 1100 ℃ to generate the polycrystalline silicon deposited on the silicon core, and the method can generate chlorosilane residues rich in Trichlorosilane (TCS), Silicon Tetrachloride (STC) and Dichlorosilane (DSC). At present, two sources of TCS in the improved Siemens method are provided, the first is to generate TCS by reacting hydrogen chloride with silicon powder, and the second is to prepare TCS by hydrogenation reaction of STC and hydrogen in chlorosilane residue. In the second method, the purity of STC affects the purity of TCS as the polysilicon raw material, and further affects the quality of polysilicon products, so that STC must be purified before preparing TCS. The main impurity elements in STC are boron, phosphorus and various metal elements.
The current methods for STC purification are mainly distillation and partial hydrolysis. The rectification method adopts a sieve plate tower, a packed tower, a float valve tower and other distillation devices, and utilizes the difference of the volatility between STC and various impurities for separation. Since the more polar the molecule, the larger the intermolecular force becomes, the more energy is required for the molecule to freely move, and the higher the boiling point is. Therefore, the rectification method has certain limitation on the removal of polar impurities, such as boron trichloride and phosphorus trichloride. The partial hydrolysis method is to remove impurities by utilizing the characteristic that boron trichloride (BCl3) is easy to hydrolyze, hydrate or complex with water with other boron-containing complexes and chlorides of some elements such as iron and aluminum to form nonvolatile compounds.
Chinese patent CN103420381A relates to a method and a device for recycling and disposing silicon tetrachloride slag slurry produced in polysilicon production, wherein the adopted method is a partial hydrolysis method, and the specific method comprises the steps of carrying out hydrolysis reaction on dried chlorosilane residues and water, removing hydrogen chloride gas generated by hydrolysis through leaching and absorption, carrying out neutralization reaction by using alkali liquor until the pH value is neutral so as to generate compound sediment containing a large amount of impurity elements, and removing the sediment containing the impurity elements through solid-liquid separation. In general, this process allows easy removal of impurities which hydrolyze preferentially to silicon-hydrogen bonds and silicon-chlorine bonds, while on the other hand a slight excess of water hydrolyzes a small portion of STC to orthosilicic acid. The generated silicic acid is easy to lose water after standing to form silica gel, and the silica gel has good adsorption effect on boron simple substance, phosphorus trichloride and other polar impurities. However, a large amount of water needs to be introduced into the hydrolysis device to perform the hydrolysis reaction, and when the chlorosilane undergoes the hydrolysis reaction, a large amount of heat released by the hydrolysis reaction easily causes the phenomena of bumping, volatilization and the like of residual liquid water inside the hydrolysis device, so that the pressure inside the hydrolysis device is increased, and even the hydrolysis device explodes in a severe case. In order to reduce the possibility of explosion, a flow controller for monitoring the water adding amount is arranged in the patent, but the patent still has certain safety hazards due to uncontrollable heat released by hydrolysis.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a device for purifying silicon tetrachloride, which carries out hydrolysis reaction by adopting crystal water in a crystal hydrate to replace liquid water, thereby realizing safe and effective impurity removal on STC.
In order to achieve the purpose, the invention provides the following technical scheme: a device for purifying silicon tetrachloride comprises a purifying device, a monitoring system and a pipeline assembly;
the purification device comprises a shell, an air inlet pipeline and an air outlet pipeline, wherein the shell is internally provided with a long-strip-shaped cavity; the front section of the strip-shaped cavity is a hydrolysis area, and the rear section of the strip-shaped cavity is a drying area; the air inlet pipeline is communicated with the front end of the hydrolysis area, and the air outlet pipeline is communicated with the rear end of the drying area; the gas outlet pipeline is communicated with a monitoring system; the hydrolysis area is uniformly distributed with an adsorbent which is a crystalline hydrate, and the drying area is uniformly distributed with a drying agent; the drying agent is silica gel or molecular sieve;
and the pipeline assembly comprises an unqualified STC pipeline and a qualified STC pipeline, the qualified STC pipeline is communicated with the monitoring system, and two ends of the unqualified STC pipeline are respectively communicated with the monitoring system and the air inlet pipeline.
By adopting the technical scheme, STC can uniformly contact with crystal water in the hydrolysis zone in the process of passing through the hydrolysis zone, so that impurities in the STC can fully react with the crystal water, and the impurity removal effect is improved; meanwhile, moisture in the drying zone is fully removed through STC in the hydrolysis zone, and the residual water content in the strip-shaped cavity is reduced, so that the possibility of explosion caused by the internal bumping evaporation of the purification device is reduced. In addition, the invention utilizes the crystal water in the crystal hydrate to replace liquid water for hydrolysis reaction, and utilizes the dehydration of the crystal hydrate to absorb the heat generated by the hydrolysis reaction, thereby further reducing the possibility of explosion of the hydrolysis device due to overhigh temperature and overlarge air pressure.
The invention is further configured to: the crystalline hydrate is acetamide containing crystal water, sodium alginate containing crystal water, or cellulose containing crystal water.
By adopting the technical scheme, the invention adsorbs the metal element impurities in STC by means of the characteristics of the three substances as the organic complexing agent, and the three substances have larger molecules, higher boiling points and stable properties, are difficult to leave the purification device along with STC gas, and reduce the possibility of introducing new impurities.
The invention is further configured to: the purification device also comprises an adsorbent carrier, wherein the adsorbent is uniformly distributed on the adsorbent carrier, and the adsorbent carrier is uniformly distributed in the hydrolysis area; the adsorbent carrier is silica gel or modified resin.
By adopting the technical scheme, when STC passes through the silica gel, water molecules and other polar impurities in the STC can be adsorbed and removed by the silica gel. When STC passes through the modified resin, the modified resin can adsorb water molecules in the STC and perform complexation on polar impurity elements in the STC.
The invention is further configured to: purification device still includes the first air guide board in the district of hydrolysising is fixed to the polylith, and the first air guide board of polylith is arranged along the district length direction linearity of hydrolysising, separates into a plurality of regions with the district of hydrolysising, and the blow vent has all been seted up to one side of every first air guide board, and the blow vent of two adjacent first air guide boards misplaces each other, evenly fills the adsorbent carrier in every two adjacent first air guide boards.
By adopting the technical scheme, the arrangement of the first air guide plate increases the path of STC in the hydrolysis zone, and increases the retention time of STC in the hydrolysis zone, so that the hydrolysis reaction is more uniform and sufficient.
The invention is further configured to: the purification device also comprises a first porous baffle fixed at the tail end of the drying zone, and the drying agent is uniformly filled between the hydrolysis zone and the first porous baffle.
Through adopting above-mentioned technical scheme, the setting of first porous baffle can reduce silica gel and get into the possibility that the gas outlet pipe left rectangular shape cavity along with the STC under the prerequisite that does not hinder STC to get into the gas outlet pipe way.
The invention is further configured to: the purification device also comprises two second porous baffle plates which are respectively fixed at two ends of the desiccant, and the desiccant is uniformly filled between the two second porous baffle plates.
The invention is further configured to: the purification device also comprises a plurality of adsorption boxes fixed in the long-strip-shaped cavity, wherein the front end of each adsorption box is positioned at the front end of the hydrolysis area, and the rear end of each adsorption box is positioned at the rear end of the drying area; each adsorption box is strip-shaped and is provided with a plurality of holes; the part of each adsorption box, which is positioned in the hydrolysis area, is filled with an adsorbent carrier, and the part, which is positioned in the drying area, is filled with a drying agent; all adsorb the box and all be on a parallel with rectangular shape cavity length direction, and leave the clearance each other.
The invention is further configured to: the purification device further comprises a second gas path guide plate, the space in the strip-shaped cavity is divided into a plurality of channels which are linearly arranged by the adsorption boxes, one end of each channel is plugged with the second gas path guide plate, and the two gas path guide plates corresponding to the two adjacent channels are respectively located in the hydrolysis area and the drying area.
Through adopting above-mentioned technical scheme, the setting of second gas circuit baffle makes STC can be even before getting into the gas outlet pipeline and contact with adsorbent and drier.
The invention is further configured to: the system also comprises two gas circuit control valves, wherein one gas circuit control valve controls the on-off of a gas circuit between the monitoring system and the unqualified STC pipeline, and the other gas circuit control valve controls the on-off of a gas circuit for outputting the qualified STC by the monitoring system.
By adopting the technical scheme, the gas circuit control valve is convenient for an operator to interrupt the gas circuit for maintenance when the gas circuit of qualified STC of the monitoring system or the gas circuit of unqualified STC has a problem.
The invention is further configured to: the purification device is used for purifying the output STC of the gas outlet pipeline and is communicated with the monitoring system.
By adopting the technical scheme, the metal impurities in the STC are further separated and removed by the purification device.
In summary, compared with the prior art, the invention has the following beneficial effects:
1. the method can ensure that STC uniformly contacts with the crystal water in the hydrolysis zone in the process of passing through the hydrolysis zone, so that impurities in the STC can fully react with the crystal water, and the impurity removal effect is improved.
2. According to the invention, moisture in the drying zone is fully removed through STC in the hydrolysis zone, so that the residual water content in the strip-shaped cavity is reduced, the possibility of explosive boiling and evaporation of the residual water caused by heat released by hydrolysis of the purification device is reduced, and the possibility of explosion of the purification device is reduced.
3. The invention utilizes the crystal water in the crystal hydrate to replace liquid water for hydrolysis reaction, and utilizes the dehydration of the crystal hydrate to absorb the heat generated by the hydrolysis reaction, thereby further reducing the possibility of explosion of the hydrolysis device due to overhigh temperature and overlarge air pressure.
Drawings
FIG. 1 is a schematic diagram showing the basic structure of embodiment 1 of the present invention;
FIG. 2 is a full sectional view of a purification apparatus in example 1 of the present invention;
FIG. 3 is a full sectional view of a purification apparatus in example 2 of the present invention;
FIG. 4 is a full sectional view of a purification apparatus in example 3 of the present invention.
In the figure: 1. a purification device; 11. a housing; 111. a strip-shaped chamber; 12. an air intake line; 13. an air outlet pipeline; 14. a first air passage guide plate; 141. a vent; 15. a first porous baffle; 16. a second porous baffle; 17. an adsorption box; 18. a second gas path guide plate; 2. a monitoring system; 3. a purification device; 5. an adsorbent carrier; 6. a desiccant; 7. qualified STC pipeline; 8. unqualified STC pipeline.
Detailed Description
The technical solutions of the present invention will be described in detail with reference to the accompanying drawings, and it is obvious that the described embodiments are not all embodiments of the present invention, and all other embodiments obtained by those skilled in the art without any inventive work belong to the protection scope of the present invention.
It is to be understood that the terms "center," "upper," "lower," "horizontal," "left," "right," "front," "rear," "lateral," "longitudinal," and the like are used in the illustrated orientation or positional relationship as shown in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting.
Example 1
As shown in fig. 1-2, which is a schematic view of embodiment 1 of the present invention, a device for purifying silicon tetrachloride comprises a purification device 1, a monitoring system 2 for detecting whether the content of impurities in STC is qualified, and a pipeline assembly; the purification device 1 comprises a shell 11, an air inlet pipeline 12 and an air outlet pipeline 13, wherein the shell is internally provided with a strip-shaped chamber 111; the two ends of the elongated cavity 111 are respectively communicated with the air inlet pipeline 12 and the air outlet pipeline 13; the gas outlet pipeline 13 is also communicated with the monitoring system 2 so as to conveniently send the purified STC to the monitoring system 2; the front section of the elongated cavity 111 is a hydrolysis area, the rear section is a drying area, adsorbents are uniformly distributed in the hydrolysis area, and drying agents 6 are uniformly distributed in the drying area; the adsorbent is a crystalline hydrate and the desiccant 6 is a granular silica gel capable of adsorbing polar molecules. The pipeline assembly comprises an unqualified STC pipeline 8 and a qualified STC pipeline 7, and the qualified STC pipeline 7 is communicated with the monitoring system 2 to output STC with qualified impurity content; two ends of the unqualified STC pipeline 8 are respectively communicated with the monitoring system 2 and the air inlet pipeline 12, so that the STC with unqualified impurity content can be fed into the elongated chamber 111 again through the air inlet pipeline 12.
When STC enters the hydrolysis zone from the air inlet pipeline 12, as the STC is in a gaseous state and has higher temperature, when the STC contacts with the crystalline hydrate, the crystalline hydrate is easy to dehydrate, so that the crystalline water is easy to perform hydrolysis reaction with impurities such as boron trichloride in the STC, and non-volatile compounds are generated; taking boron trichloride hydrolysis as an example, the reaction mechanism is as follows: BCl 3 +3H 2 O＝B(OH) 3 +3 HCl. Furthermore, the crystal water can be complexed with impurities such as boron trichloride in STC to form a non-volatile complex, such as B (OH) 3 (ii) a Another small part of STC can be hydrolyzed with crystal water to produce ortho-silicic acid (H) 2 SiO 4 ) The reaction formula is as follows: SiCl 4 +4H 2 O＝H 2 SiO4+4HCl, by virtue of the characteristic of orthosilicic acid that volatilizes water to silica gel, produces silica gel to help adsorb water molecules and polar impurities. And then STC passing through the hydrolysis zone enters a drying zone, and water molecules and polar impurities in the STC are further adsorbed and removed by silica gel. The STC leaving the drying zone will then leave the purification device 1 through the gas outlet line 13 and enter the monitoring system 2 for impurity content detection to output STC with qualified impurity content.
The process of losing water of crystallization of crystalline hydrates is the breaking of chemical bonds, which requires the absorption of heat. In the embodiment, STC uniformly contacts with the crystal water in the hydrolysis zone in the process of passing through the hydrolysis zone, so that impurities in the STC can fully react with the crystal water, and the impurity removal effect is improved; meanwhile, moisture in the drying zone is fully removed through STC in the hydrolysis zone, so that the content of residual water in the elongated chamber 111 is reduced, the possibility of explosive boiling and evaporation of the residual water caused by heat released by hydrolysis of the purification device 1 is reduced, and the possibility of explosion of the purification device 1 is reduced. In addition, in the embodiment, the crystal water in the crystal hydrate is used for replacing liquid water to perform the hydrolysis reaction, and the heat generated by the hydrolysis reaction is absorbed by dehydration of the crystal hydrate, so that the possibility of explosion of the hydrolysis device due to overhigh temperature and overlarge air pressure is further reduced.
Specifically, the elongated cavity 111 in this embodiment is in the shape of a capsule, and two ends of the elongated cavity are respectively and smoothly contracted towards the air inlet pipeline 12 and the air outlet pipeline 13, so that the STC can smoothly enter the hydrolysis zone and smoothly leave the elongated cavity 111.
Specifically, the method comprises the following steps. The pipe diameter of the air inlet pipeline 12 is greater than that of the air outlet pipeline 13 in this embodiment, so that the flow velocity of the air outlet pipeline 13 is less than that of the air inlet pipeline 12, the retention time of the STC in the elongated cavity 111 is prolonged, and the STC can be conveniently and fully contacted with the crystal water and the silica gel in the elongated cavity 111.
Specifically, the purification device 1 further comprises an adsorbent carrier 5, the adsorbent is uniformly distributed on the adsorbent carrier 5, and the adsorbent carrier 5 is uniformly distributed in the hydrolysis area; the adsorbent carrier 5 is silica gel, and can be filled in an adsorption column or a functional container similar to the adsorption column.
Specifically, purification device 1 still includes that the polylith is located the district of hydrolysising and with shell 11 inside wall fixed connection's first air guide plate 14, all first air guide plates 14 are arranged along the district length direction linearity of hydrolysising, separate into a plurality of regions with the district of hydrolysising, the vent 141 that the STC of being convenient for passed through is all seted up to one side of every first air guide plate 14, vent 141 of two adjacent first air guide plates 14 misplaces each other, evenly fill adsorbent carrier 5 in every two adjacent first air guide plates 14. The arrangement of the first gas circuit guide plate 14 enables the STC to only pass through the hydrolysis zone through the vent port 141, the path of the STC in the hydrolysis zone is increased, the retention time of the STC in the hydrolysis zone is increased, and the hydrolysis reaction is more uniform and sufficient.
Specifically, in the present embodiment, the first air guiding plates 14 are divided into two groups, the two groups of first air guiding plates 14 are disposed at intervals, the vent holes 141 of one group of first air guiding plates 14 are located at the top of the elongated cavity 111, and the vent holes 141 of the other group of first air guiding plates 14 are located at the bottom of the elongated cavity 111, so as to further increase the path of STC in the hydrolysis area.
Specifically, the purification device 1 further comprises a first porous baffle 15 positioned at the end of the drying zone and fixedly connected with the inner side wall of the housing 11, and the drying agent 6 is uniformly filled between the hydrolysis zone and the first porous baffle 15. The arrangement of the first porous baffle 15 can reduce the possibility that silica gel enters the air outlet pipeline 13 along with the STC and leaves the elongated cavity 111 on the premise of not obstructing the STC from entering the air outlet pipeline 13.
The embodiment also comprises two gas path control valves, wherein one gas path control valve controls the on-off of a gas path between the monitoring system 2 and the unqualified STC pipeline, and the other gas path control valve controls the on-off of a gas path between the monitoring system 2 and the qualified STC pipeline 7. The gas path control valve is arranged to facilitate the control of the on-off of the gas path between the monitoring system 2 and the qualified STC pipeline 7 or the unqualified STC pipeline 8 by an operator so as to facilitate the maintenance.
The embodiment further comprises a purification device 3 for purifying STC output by the gas outlet pipeline 13, wherein the gas outlet pipeline 13 is communicated with the purification device 3, and the purification device 3 further separates and removes impurities in the STC. The STC purified again by the purifying device 3 is sent to the monitoring system 2 for impurity content assessment.
Specifically, in this embodiment, the purifying apparatus 3 is an apparatus for removing impurities in STC by using a rectification method, so as to further remove metal element impurities therein, and remove a very small amount of macromolecular substances such as acetamide and HCl which are included in STC by using a rectification method.
Specifically, the monitoring system 2 in this embodiment detects impurities in STC by using infrared spectroscopy.
In this example, the crystalline hydrate is acetamide containing water of crystallization. Acetamide is used as an organic complexing agent, can adsorb metal element impurities in STC, has large molecules, high boiling point and stable property, is difficult to leave a purification device along with STC gas, and reduces the possibility of introducing new impurities. And because the heat brought by gaseous STC and the heat generated by hydrolysis reaction exist in the hydrolysis zone, the temperature is higher, so that acetamide (CH3CONH2) has a certain probability to be dehydrated to generate acetonitrile (CH3CN), and the acetonitrile also has good complexation effect on metal element impurities, so that the metal element impurities in STC can be removed. Because the boiling point of the acetonitrile is higher than STC, the property is stable, the acetonitrile is difficult to leave the purification device along with STC gas, and new impurities are difficult to introduce.
The proportion of acetamide crystalline water adsorbent to silica gel desiccant is 10: 1-1: 1, optimal ratio 4: purification of the resulting STC and the impurity levels in the original STC are shown in Table 1:
TABLE 1 corresponding STC impurity content
| Impurities (Unit) | Original content | Final content of |
| P(ppba) | 0.68 | 0.09 |
| B(ppba) | 0.58 | 0.02 |
| Fe(pptw，10-9) | 3 | 0.39 |
| Cr(pptw，10-9) | 2 | 0.23 |
| Zn(pptw，10-9) | 1 | 0.14 |
In conclusion, the embodiment can enable STC to uniformly contact with the crystal water in the hydrolysis zone in the process of passing through the hydrolysis zone, so that impurities in the STC can fully react with the crystal water, and the impurity removal effect is improved; meanwhile, moisture in the drying zone is fully removed through STC in the hydrolysis zone, so that the content of residual water in the elongated chamber 111 is reduced, the possibility of explosive boiling and evaporation of the residual water caused by heat released by hydrolysis of the purification device 1 is reduced, and the possibility of explosion of the purification device 1 is reduced. In addition, in the embodiment, the crystal water in the crystal hydrate is used for replacing liquid water to perform the hydrolysis reaction, and the dehydration of the crystal hydrate is used for absorbing the heat generated by the hydrolysis reaction, so that the possibility of explosion of the hydrolysis device due to overhigh temperature and overlarge air pressure is further reduced.
Example 2
FIG. 3 is a schematic sectional view of the purification apparatus 1 according to example 2 of the present invention. The present embodiment differs from embodiment 1 as follows:
in this example, the adsorbent carrier 5 is weakly basic modified resin and has a bulk density of 0.40-0.60/ml. The modified resin can adsorb water molecules in STC and perform complexation on polar impurity elements in STC. The drying agent 6 is a molecular sieve which is artificially synthesized hydrated aluminosilicate or natural zeolite with the function of screening molecules. The crystal cavities of the molecular sieve have stronger polarity, so that the molecular sieve can generate stronger adsorption force on molecules containing polar groups.
In this embodiment, the purification apparatus 1 further comprises two second porous baffles 16, the two second porous baffles 16 are respectively located at two ends of the drying region and are fixedly connected to the inner side wall of the housing 11, and the molecular sieve is uniformly filled between the two porous baffles. Because the hydrolysis area contains more water molecules, the two second porous baffle plates 16 and the inner side wall of the shell 11 form an isolation space which can isolate the water molecules in the hydrolysis area outside the drying area as much as possible, and the drying effect of the drying agent 6 is improved. In this embodiment, a gap is left between the hydrolysis zone and the drying zone to further separate the hydrolysis zone from the drying zone, thereby reducing the possibility of water molecules entering the drying zone in the hydrolysis zone.
In this embodiment, there is no purification device 3, and the gas outlet pipeline 13 is directly connected to the monitoring system 2.
The STC finally obtained by purification and the impurity content in the original STC are shown in the table 2, and the impurity content in the STC is effectively reduced after passing through the purification device;
TABLE 2 corresponding STC impurity content
| Impurities (Unit) | Original content | Final content of |
| P(ppba) | 0.68 | 0.08 |
| B(ppba) | 0.58 | 0.03 |
| Fe(pptw，10-9) | 3 | 0.32 |
| Cr(pptw，10-9) | 2 | 0.20 |
| Zn(pptw，10-9) | 1 | 0.22 |
Example 3
Fig. 4 is a full sectional view of the purification apparatus 1 according to example 3 of the present invention. The present embodiment differs from embodiment 2 as follows:
specifically, the purification device 1 further comprises a plurality of adsorption boxes 17 fixedly connected with the inner side wall of the shell 11, wherein the front end of each adsorption box 17 is positioned at the front end of the hydrolysis area, and the rear end is positioned at the rear end of the drying area; each adsorption box 17 is strip-shaped, and the box body is uniformly provided with a plurality of holes; the part of each adsorption box 17 positioned in the hydrolysis zone is filled with adsorbent carriers 5, and the part positioned in the drying zone is filled with molecular sieves; all the adsorption boxes 17 are parallel to the length direction of the elongated cavity 111, and gaps are reserved between the adsorption boxes. Four adsorption cassettes 17 are provided in this embodiment.
Specifically, the purification device 1 further includes a second gas path guide plate 18; the four adsorption boxes 17 divide the elongated cavity 111 into five linearly arranged channels, and all the channels are communicated with the air inlet pipeline 12 and the air outlet pipeline 13; one end of each channel is blocked with a second gas circuit guide plate 18, and two gas circuit guide plates corresponding to two adjacent channels are respectively positioned at the front end of the hydrolysis area and the rear end of the drying area. The second air path guide plate 18 is arranged to enable the STC to enter the air outlet pipeline 13 only through the adsorption boxes 17, and since the path of the STC passing through one adsorption box 17 is not a straight line along the length direction of the channel, the STC is likely to contact with another adsorption box 17 on the side wall of the channel, even pass through another adsorption box 17, so that the STC can sufficiently contact with the adsorbent and the desiccant 6 to carry out hydrolysis reaction and remove excessive moisture.
The STC finally obtained by purification and the impurity content in the original STC are shown in the table 3, and the impurity content in the STC is effectively reduced after passing through the purification device;
TABLE 3 corresponding STC impurity content
| Impurities (Unit) | Original content | Final content of |
| P(ppba) | 0.68 | 0.13 |
| B(ppba) | 0.58 | 0.05 |
| Fe(pptw，10-9) | 3 | 0.42 |
| Cr(pptw，10-9) | 2 | 0.10 |
| Zn(pptw，10-9) | 1 | 0.12 |
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A device for purifying silicon tetrachloride is characterized in that: comprises a purification device (1), a monitoring system (2) and a pipeline component;
the purification device (1) comprises a shell (11) with a strip-shaped chamber (111) arranged inside, an air inlet pipeline (12) and an air outlet pipeline (13); the front section of the strip-shaped cavity (111) is a hydrolysis area, and the rear section is a drying area; the air inlet pipeline (12) is communicated with the front end of the hydrolysis area, and the air outlet pipeline (13) is communicated with the rear end of the drying area; the gas outlet pipeline (13) is communicated with the monitoring system (2); adsorbents are uniformly distributed in the hydrolysis area, and are crystalline hydrates; drying agents (6) are uniformly distributed in the drying area, and the drying agents (6) are silica gel or molecular sieves;
the pipeline assembly comprises an unqualified STC pipeline (8) and a qualified STC pipeline (7), the qualified STC pipeline (7) is communicated with the monitoring system (2), and two ends of the unqualified STC pipeline (8) are respectively communicated with the monitoring system (2) and the air inlet pipeline (12).
2. A device for purifying silicon tetrachloride according to claim 1, which is characterized in that: the crystalline hydrate is acetamide containing crystal water, sodium alginate containing crystal water, or cellulose containing crystal water.
3. A device for purifying silicon tetrachloride according to claim 1, characterized in that: the purification device (1) also comprises adsorbent carriers (5), the adsorbent is uniformly distributed on the adsorbent carriers (5) between the baffles, and the adsorbent carriers (5) are uniformly distributed in the hydrolysis area; the adsorbent carrier (5) can be silica gel or modified resin, and can be filled in an adsorption column or a functional container similar to the adsorption column.
4. A device for purifying silicon tetrachloride according to claim 3, wherein the device comprises: purification device (1) still includes that the first air guide board (14) in the district of hydrolysising is fixed to the polylith, and polylith first air guide board (14) are arranged along the district length direction linearity of hydrolysising, and blow vent (141) have all been seted up to one side of every first air guide board (14), and blow vent (141) of two adjacent first air guide boards (14) misplace each other, evenly fill adsorbent carrier (5) in every two adjacent first air guide boards (14).
5. A device for purifying silicon tetrachloride according to claim 4, characterized in that: the purification device (1) also comprises a first porous baffle (15) fixed at the tail end of the drying zone, and the drying agent (6) is uniformly filled between the hydrolysis zone and the first porous baffle (15).
6. A device for purifying silicon tetrachloride according to claim 4, characterized in that: the purification device (1) further comprises two second porous baffles (16) which are respectively fixed at two ends of the desiccant (6), and the desiccant (6) is uniformly filled between the two second porous baffles (16).
7. A device for purifying silicon tetrachloride according to claim 3, wherein the device comprises: the purification device (1) also comprises a plurality of adsorption boxes (17) fixed in the elongated chamber (111), wherein the front end of each adsorption box (17) is positioned at the front end of the hydrolysis area, and the rear end of each adsorption box (17) is positioned at the rear end of the drying area; each adsorption box (17) is strip-shaped and is provided with a plurality of holes; each adsorption box (17) is positioned in the hydrolysis area, is partially filled with an adsorbent carrier (5), and is positioned in the drying area, is partially filled with a drying agent (6); all the adsorption boxes (17) are parallel to the length direction of the strip-shaped chamber (111), and gaps are reserved among the adsorption boxes.
8. A device for purifying silicon tetrachloride according to claim 7, characterized in that: purification device (1) still includes second gas circuit baffle (18), and a plurality of absorption box (17) are cut apart into the space in rectangular shape cavity (111) many channels of linearly arranging, and one end of every channel all blocks up a second gas circuit baffle (18), and two gas circuit baffles that two adjacent channels correspond are located hydrolysis area and drying zone respectively.
9. A device for purifying silicon tetrachloride according to claim 1, characterized in that: the automatic air-path control system further comprises two air-path control valves, one air-path control valve controls the connection and disconnection of an air path between the monitoring system (2) and an unqualified STC pipeline, and the other air-path control valve controls the connection and disconnection of an air path for outputting the qualified STC by the monitoring system (2).
10. A device for purifying silicon tetrachloride according to claim 1, characterized in that: the purification device (3) for purifying STC output by the gas outlet pipeline (13) is further included, and the purification device (3) is communicated with the monitoring system (2).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210528352.9A CN115040975A (en) | 2022-05-16 | 2022-05-16 | Device for purifying silicon tetrachloride |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210528352.9A CN115040975A (en) | 2022-05-16 | 2022-05-16 | Device for purifying silicon tetrachloride |
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