A drying apparatus for silicon tetrachloride containing aqueous hydrogen chloride

Abstract

This application discloses a drying device for silicon tetrachloride containing aqueous hydrogen chloride, comprising a bubbling tank and at least two spray tanks. Each spray tank is connected to the bubbling tank via a connecting pipe. Valves are installed at each connecting pipe to control the connection status between the bubbling tank and each spray tank. In operation, the bubbling tank is connected to at least one spray tank, while the connecting pipe between at least one other spray tank and the bubbling tank is closed. Even when the separate bubbling tank and spray tank become clogged, increasing the pressure difference between the spray tank and the bubbling tank, the drying device can still operate normally. Only the remaining spare spray tanks need to be replaced, and the clogged spray tank needs to be shut down. No system shutdown for maintenance is required, increasing the equipment's operating efficiency. The deactivated spray tanks can be cleaned and repaired individually and then put back into service after cleaning.

Description

Technical Field

[0001] This application relates to the field of hydrogen chloride drying technology, and in particular to a silicon tetrachloride drying apparatus for aqueous hydrogen chloride. Background Technology

[0002] In existing drying towers for hydrochloric acid, the hydrochloric acid is sent to a silicon tetrachloride drying tower for drying and dehydration. The hydrochloric acid comes into countercurrent contact with the -20°C silicon tetrachloride sprayed down from the top of the tower. After removing the trace amounts of moisture carried by the hydrochloric acid, it is sent out from the top of the silicon tetrachloride drying tower, and the liquid level in the drying tower is maintained at 70%.

[0003] The existing drying tower's internal components—the aqueous hydrogen chloride inlet, the silicon tetrachloride spray, and the wire mesh demister—are all located within the same tower. Silicon tetrachloride absorbs moisture from the hydrogen chloride to form silicic acid, which, through gas-liquid entrainment, easily clogs the silicon tetrachloride spray and the wire mesh demister, increasing the pressure difference between the inlet and outlet at the top of the tower. Due to the integrated design within the drying tower, this can lead to system shutdowns for maintenance. Summary of the Invention

[0004] The purpose of this application is to provide a silicon tetrachloride drying device containing aqueous hydrogen chloride that can be maintained without shutting down the system.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: a silicon tetrachloride drying device containing aqueous hydrogen chloride, comprising a bubbling tank and at least two spray tanks, each of the spray tanks being connected to the bubbling tank via a connecting pipe, and a valve being provided at each of the connecting pipes to control the connection state between the bubbling tank and each of the spray tanks respectively. In the working state, the bubbling tank is connected to at least one of the spray tanks, and the connecting pipe between at least one of the spray tanks and the bubbling tank is closed.

[0006] As a preferred embodiment, the spray tank includes a hydrogen chloride inlet at the bottom and a hydrogen chloride outlet at the top, and a downward-spraying spray head is provided inside the spray tank; a level gauge is provided inside the spray tank, with the lowest range of the level gauge located below the spray head; the drying device is adapted to stop operating when the liquid level in the spray tank reaches the height of the level gauge and to switch the spray tank connected to the bubbling tank via the valve.

[0007] As a preferred embodiment, a pressure gauge is provided inside each of the spray tanks and the bubble tanks. A wire mesh plate for preventing gas-liquid entrainment is provided in the upper middle part of the inner cavity of the spray tank. The pressure gauge inside the spray tank is located above the wire mesh plate. The drying device is adapted to stop operating when the pressure inside the bubble tank exceeds the pressure setting range inside any of the spray tanks and to switch the spray tank connected to the bubble tank through the valve.

[0008] As a preferred embodiment, the drying device further includes a silicon tetrachloride circulation inlet, a silicon tetrachloride discharge outlet, a silicon tetrachloride feed inlet, a silicon tetrachloride circulation outlet, and a circulation refrigeration component connected in sequence. The circulation refrigeration component is connected to the silicon tetrachloride circulation inlet so that liquid silicon tetrachloride passes through in sequence and forms a circulation. The silicon tetrachloride discharge outlet and the silicon tetrachloride circulation inlet are located on the spray tank, and the silicon tetrachloride feed inlet and the silicon tetrachloride circulation outlet are located on the bubbling tank.

[0009] As a preferred embodiment, the bubbling tank is provided with an aqueous hydrogen chloride inlet at the bottom and an aqueous hydrogen chloride outlet at the top, the hydrogen chloride inlet being connected to the aqueous hydrogen chloride outlet, an annular baffle plate being provided at the bottom of the inner cavity of the spray tank, the bottom inner cavity of the spray tank and the baffle plate being combined to form a liquid collecting cylinder, the annular inner cavity of the baffle plate covering the entire hydrogen chloride inlet, a gas dispersion structure being provided directly above the liquid collecting cylinder of the spray tank, and a downward spraying nozzle being provided at a position in the inner cavity of the spray tank higher than the gas dispersion structure.

[0010] As a preferred embodiment, the gas dispersion structure is configured as a rain cap-type gas distributor, and the spray head is a spiral sprayer.

[0011] As a preferred embodiment, the inner cavity of the bubbling tank is provided with a bubble-breaking plate, and the liquid level in the inner cavity of the bubbling tank is higher than the bubble-breaking plate and the water-containing hydrogen chloride inlet; a wire mesh plate is provided in the upper middle part of the inner cavity of the spray tank, and the wire mesh plate is located above the spiral sprayer.

[0012] As a preferred embodiment, the bubbling tank is provided with a high-purity silicon tetrachloride inlet, and the connecting pipe is provided with a silicon tetrachloride drain outlet at its bottom and above the valve.

[0013] As a preferred embodiment, the bottom of the bubbling tank is provided with a base, the base fixing the silicon tetrachloride circulation outlet, and an inspection port and an exhaust port are respectively provided on the upper and lower sides of the silicon tetrachloride circulation outlet; a spare port is provided on the top of the bubbling tank.

[0014] As a preferred embodiment, both the spray tank and the bubble tank are provided with inspection ports below the wire mesh plate.

[0015] Compared with the prior art, the beneficial effects of this application are as follows:

[0016] The originally integrated drying tower has been divided into separate bubbling tanks and spray tanks. Even in the event of blockage and increased pressure difference between the spray tank and the bubbling tank, the drying unit can still operate normally. Only the spare spray tank needs to be replaced, and the blocked spray tank shut down. No system shutdown for maintenance is required, increasing equipment operating efficiency. The deactivated spray tanks can be cleaned and repaired individually and then put back into service after cleaning.

[0017] The liquid level gauge is set up so that when impurities clog the inside of the spray tank, it will affect the discharge of silicon tetrachloride. At this time, silicon tetrachloride accumulates in the spray tank and causes the liquid level to rise. When the liquid level reaches the level gauge, the reading is obtained. This indicates that the liquid level has accumulated to a certain extent, indicating that maintenance is required, so that timely handling can be carried out.

[0018] By using a pressure gauge, when a blockage occurs, the hydrogen chloride gas in the bubbling tank is difficult to enter the spray tank through the blockage, making the pressure in the spray tank above the blockage significantly lower than the pressure inside the bubbling tank. When the difference exceeds a certain range, it indicates that maintenance is needed, preventing the pressure from increasing excessively and facilitating timely handling. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of one embodiment of this application.

[0020] Figure 2 yes Figure 1 A schematic diagram of the spray tank.

[0021] Figure 3 yes Figure 1 A schematic diagram of a medium-sized bubbling tank.

[0022] Figure 4 This is a schematic diagram of the connecting pipes.

[0023] In the diagram: 1. Bubble tank; 2. Connecting pipe; 3. Spray tank; 4. Wire mesh plate; 5. Spray frame; 6. Rain cap type gas distributor; 7. Isolation plate; 8. Fixed pressure plate; 9. Ball valve; 10. Spiral sprayer; 11. Bubble breaking plate. Detailed Implementation

[0024] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0025] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0026] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0027] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0028] See Figures 1 to 4 As shown, this application proposes a silicon tetrachloride drying device containing aqueous hydrogen chloride, including a spray tank 3 and a bubbling tank 1. Each bubbling tank 1 is provided with multiple spray tanks 3 corresponding to it and connected by a connecting pipe 2. Valves are provided at the connection points of the connecting pipe 2 to control their opening and closing. In the working state, one bubbling tank 1 is simultaneously connected to at least one spray tank 3, and the connecting pipe corresponding to at least another spray tank 3 is closed.

[0029] This drying unit divides the originally integrated drying tower into separate bubbling tank 1 and spray tank 3. Even in the event of blockage, when the pressure difference between spray tank 3 and bubbling tank 1 increases, the drying unit can still operate normally. Only a spare spray tank 3 needs to be installed, and the blocked spray tank 3 needs to be shut down. No system shutdown for maintenance is required, increasing equipment operating efficiency. The disabled spray tank 3 can be cleaned and inspected individually and then put back into service after cleaning.

[0030] For ease of understanding, this embodiment uses a scenario with one bubbling tank 1 and two spray tanks 3 as an example. The connecting pipe 2 is as follows: Figure 4 As shown, it is actually a tee fitting.

[0031] Preferably, the following two maintenance judgment criteria are given:

[0032] The first method involves determining the need for maintenance by monitoring the liquid level at the bottom of spray tank 3. Spray tank 3 includes a hydrogen chloride inlet at the bottom and a hydrogen chloride outlet at the top. It contains downward-facing spray heads and a level gauge with its lowest range located below the spray heads. The drying device is designed to stop operating when the liquid level in spray tank 3 reaches the gauge height and to switch the connection between spray tank 3 and bubbling tank 1 via a valve. Bubbling tank 1 has a water-containing hydrogen chloride inlet N1 below the liquid level and a water-containing hydrogen chloride outlet N5 at its top. When impurities clog spray tank 3, they affect the discharge of silicon tetrachloride, causing it to accumulate and raise the liquid level. A reading is taken when the liquid level reaches the gauge level, indicating that maintenance is required.

[0033] The application sets the lowest range of the level gauge below the spray head, rather than above it or at the bottom of the spray tank 3, for the following reasons: (1) When silicon tetrachloride is sprayed, the spray volume is relatively large, and a certain amount of silicon tetrachloride will inevitably accumulate at the bottom of the spray tank 3. Therefore, the bottom of the level gauge is not set at the bottom of the spray tank 3; (2) At the same time, the level gauge cannot be set too high. If it is set too high, too much silicon tetrachloride will accumulate, exceeding the spray head, and the hydrogen chloride gas cannot be sprayed to remove water. Considering the above, the application sets the lowest range of the level gauge at a certain distance below the spray head. This allows for a prompt for maintenance before water removal is impossible, and also gives the operator enough time to perform the reaction operation. The level gauge at this time corresponds to Figure 1 The liquid level gauge ports L5 and L8 in TL5 and TL8; of course, it can also be like... Figure 1 The remaining liquid level gauges are set up with L1, L2, L3, L4, L6, L7, etc. Among them, the liquid level gauges at L6 and L7 can be used to detect the liquid level in spray tank 3, and can be used when cleaning spray tank 3; L1 and L2 can detect the liquid level in bubbling tank, and can be used to detect the liquid level in bubbling tank during normal drying process.

[0034] The second method determines whether maintenance is needed by measuring the pressure difference between the spray tank 3 and the bubbling tank 1. Each spray tank 3 and each bubbling tank 1 is equipped with a pressure gauge, with the pressure gauge in the spray tank 3 positioned above the area prone to clogging (e.g., ...). Figure 1The pressure gauges P2 and P3 are mainly located at the top to detect pressure, while the pressure gauge in the bubbling tank 1 is located at position P1. The drying device is adapted to stop operation when the pressure inside the bubbling tank 1 exceeds the pressure setting range inside any of the spray tanks 3, and to switch the spray tank 3 connected to the bubbling tank 1 via a valve. When the ball valve 9 is open, the pressure inside the spray tank 3 and the bubbling tank 1 is generally the same or similar. When a blockage occurs inside the spray tank 3 (mainly the wire mesh plate 4, or possibly the hydrogen chloride inlet), the hydrogen chloride gas in the bubbling tank 1 has difficulty entering the spray tank 3 through the blockage (it cannot enter or entering becomes relatively difficult). At this time, the pressure in the spray tank 3 above the blockage is significantly lower than the pressure inside the bubbling tank 1. When this difference is greater than 10 kPa, it generally indicates that maintenance is needed. At this time, the wire mesh plate 4 is not completely blocked, so the pressure will not increase excessively, prompting the operator to replace the spray tank 3 for maintenance without stopping the machine. The pressure difference mentioned above can be adjusted up or down according to actual needs, for example, to the range of 5 kPa-15 kPa.

[0035] Obviously, both of the above solutions can coexist in this drying device, or they can be set up separately. When both solutions exist, the one that is achieved first will be used as the standard for maintenance.

[0036] This drying device mainly includes the following two material flow paths:

[0037] (1) The first is the overall flow of silicon tetrachloride. Silicon tetrachloride is a desiccant. In this embodiment, after the silicon tetrachloride is dried to remove aqueous hydrogen chloride, it is discharged from the bubbling tank 1 and, after cooling and impurity removal, is returned to the equipment for recycling. Specifically, as follows: Figure 1 , Figure 3 As shown, the drying device includes a silicon tetrachloride circulation inlet N4 and silicon tetrachloride outlets N8-N11 connected in sequence (N8 and N9 are...). Figure 2 The discharge port on the left, N10 / N11 is Figure 2 The system includes a discharge port on the right side, silicon tetrachloride inlets N14-15 (corresponding to N14 and N15 in the two spray tanks 3 respectively), a silicon tetrachloride circulation outlet N2, and a circulation refrigeration component (not shown in the figure, mainly including a pump body for circulating liquid and a refrigeration component for silicon tetrachloride). The circulation refrigeration component is connected to the silicon tetrachloride circulation inlet N4 to allow liquid silicon tetrachloride to pass through sequentially and form a circulation. Silicon tetrachloride discharge ports N8 to N11 and silicon tetrachloride circulation inlet N4 are located on spray tank 3, while silicon tetrachloride inlets N14-15 and silicon tetrachloride circulation outlet N2 are located on bubbling tank 1. The interfaces that are not directly connected are connected by pipes.

[0038] (2) The second is the overall flow of aqueous hydrogen chloride. Aqueous hydrogen chloride enters through the aqueous hydrogen chloride inlet N1 at the lower position of the bubbling tank 1. The initial silicon tetrachloride liquid level in the bubbling tank 1 is about 70%. After entering, the aqueous hydrogen chloride undergoes bubbling treatment in the liquid silicon tetrachloride to perform preliminary drying treatment. Subsequently, the aqueous hydrogen chloride, with some water removed, enters the connecting pipe 2 through the aqueous hydrogen chloride outlet N5 and the hydrogen chloride inlet (also corresponding to N5, the inlet at the bottom of the spray tank 3 is regarded as the hydrogen chloride inlet), and then enters the spray tank 3 after passing through the ball valve 9. The silicon tetrachloride liquid at about -20℃ enters through the silicon tetrachloride circulation inlet N4 and is sprayed through the spray head, so that the hydrogen chloride and silicon tetrachloride come into full contact in opposite directions, thereby removing most of the water. Then, the dried hydrogen chloride gas is discharged from the hydrogen chloride outlets N6 and N7 at the top of the spray tank 3. Figure 1 , Figure 3 As shown, the bubbling tank 1 is provided with a water-containing hydrogen chloride inlet N1 at the bottom and a water-containing hydrogen chloride outlet N5 at the top. The hydrogen chloride inlet (located at the bottom of the spray tank 3) is connected to the water-containing hydrogen chloride outlet N5.

[0039] When inspecting and cleaning the silicon tetrachloride spray nozzles and wire mesh plate 4, no water washing or alkaline washing is required, and maintenance personnel do not need to enter the equipment. Cleaning is completed simply by rinsing, soaking, draining, and circulating high-purity silicon tetrachloride multiple times, preparing the equipment for future use. Of course, the principle behind this cleaning method using silicon tetrachloride, besides rinsing and soaking, also benefits from the timed replacement of the silicon tetrachloride in this drying device. Generally, the silicon tetrachloride is replaced approximately every four hours. Through this operation, the precipitate produced after the silicon tetrachloride absorbs water can be discharged regularly, reducing the time it accumulates inside the equipment.

[0040] When replacing silicon tetrachloride, stop feeding hydrogen chloride and discharge silicon tetrachloride directly from the silicon tetrachloride circulation outlet N2, without it entering the circulating refrigeration unit for circulation. The spray tank 3 is emptied through the silicon tetrachloride outlets N8 to N11. Under normal use, there is almost no silicon tetrachloride inside the connecting pipe 2, so no additional operation is usually required. After emptying, feed through the high-purity silicon tetrachloride inlet N3 until the liquid level of the bubbling tank 1 is 70%.

[0041] To prevent silicon tetrachloride from entering the connecting pipe 2, an annular baffle plate 7 is installed at the bottom of the inner cavity of the spray tank 3. The bottom inner cavity of the spray tank 3 and the baffle plate 7 are combined to form a liquid collection cylinder. The annular inner cavity of the baffle plate 7 covers the entire hydrogen chloride inlet. A gas dispersion structure is installed directly above the liquid collection cylinder of the spray tank 3. A downward spray head is installed in the inner cavity of the spray tank 3 at a position lower than the rain cap-type gas distributor 6. The spray head is higher than the gas dispersion structure.

[0042] The gas dispersion structure is preferably configured as a rain cap-type gas distributor 6, and the spray head is preferably configured as a spiral sprayer 10, such as... Figure 2 As shown, a spray frame 5 can be installed to fix the spiral sprayer 10. The spray frame 10 is connected to the silicon tetrachloride circulation inlet N4. A rain cap-type gas distributor 6 is shown... Figure 2 As shown, its cross-sectional projection is shaped like a rain cap, and its specific structure is generally conical, such as a cone. The significance of this design is that the rain cap-type gas distributor allows the gas to diffuse outward along the rain cap structure after passing through the obstruction. At this time, the downward spraying of silicon tetrachloride allows for full contact between the gas and liquid, thereby ensuring a better drying effect. In this application, the aqueous hydrogen chloride gas is sprayed from bottom to top, and the sprayed silicon tetrachloride liquid is sprayed from top to bottom. Due to the guiding effect of the rain cap, the gas will slow down and rise along the relatively close inner edge of the spray tank 3. The spiral sprayer 10 preferably used in this application, due to the spiral shape of the nozzle, often produces a conical spray of liquid during spraying. The hydrogen chloride gas, after being guided by the rain cap structure, perfectly matches this shape. Therefore, this combination can greatly improve the utilization rate of silicon tetrachloride liquid and also significantly improve the drying effect.

[0043] In some embodiments, the gas dispersion structure may also be other structures, such as a plate with several evenly distributed and relatively dense small holes on the plate, so that the gas can be dispersed and discharged. However, this requires the gas to be continuously discharged, thereby preventing or reducing the spray liquid from entering the connecting pipe or further into the bubble tank 1 from these small holes, so it is not a preferred solution.

[0044] like Figure 1 , Figure 3As shown, the inner cavity of the bubbling tank 1 is equipped with a bubble-breaking plate 11. During normal operation, the liquid level in the inner cavity of the bubbling tank is higher than the bubble-breaking plate 11 and the water-containing hydrogen chloride inlet N1. The bubble-breaking plate 11 has a relatively large aperture. Its function is to reduce the gas-liquid entrainment effect when hydrogen chloride gas is bubbled, when silicon tetrachloride itself volatilizes to form gas / mist, or when the gas generated by bubbling passes through. Due to the high viscosity and poor solubility of the silicic acid formed after silicon tetrachloride absorbs water, if a large amount enters the subsequent pipeline or spray tank 3, it will adhere and form impurities / scale at the flow point. Cleaning impurities in the closed pipeline is relatively difficult, so it is necessary to reduce the generation of such impurities. The bubble-breaking plate 11 can effectively reduce the above-mentioned entrainment effect, thereby reducing the generation of impurities and scale. Similarly, a wire mesh plate 4 is provided in the upper middle part of the inner cavity of the spray tank 3. The wire mesh plate 4 is located above the spiral sprayer 10. The wire mesh plate 4 can also be called a wire mesh defoaming plate. When silicon tetrachloride atomized by the spiral sprayer 10 comes into contact with the upward-moving hydrogen chloride gas, foam may be generated. During the gas rising process, such foam / bubbles will be discharged together, resulting in the material after discharge not being pure enough. Therefore, this application sets a wire mesh plate 4 with relatively small mesh size to prevent or reduce the inclusion of silicon tetrachloride or other impurities (such as silicic acid) after hydrogen chloride is dried.

[0045] Hydrogen chloride gas comes into full contact with silicon tetrachloride in the bubbling tank 1 through bubbling, thus performing a preliminary dehydration operation. During this operation, due to the volatility of the silicon tetrachloride liquid and the gas-liquid entrainment of hydrogen chloride, hydrogen chloride gas will be entrained with silicon tetrachloride liquid, and some "mist" will be generated by the volatilization of silicon tetrachloride. The bubble-breaking plate 11 can reduce the gas-liquid entrainment and the volatilization loss of silicon tetrachloride through collision, interception and other principles, thereby ensuring the purity of the hydrogen chloride discharged after the preliminary treatment by the bubbling tank 1.

[0046] Wire mesh plate 4 Figure 2 As shown, since wire mesh is generally made of relatively soft material, it can be fixed by setting fixing plates 8 at both ends. This fixing method is preferably a detachable installation method, which facilitates subsequent maintenance and replacement.

[0047] Obviously, the aforementioned wire mesh plate 4 and bubble-breaking plate 11, due to their obstruction of gas-liquid entrainment during actual production, become the places where impurities are most easily accumulated in the entire equipment. This is especially true for wire mesh plate 4, which has a smaller pore size, resulting in stronger filtration of high-viscosity impurities and higher adhesion to them. Therefore, the degree of clogging of wire mesh plate 4 is usually higher. Furthermore, as... Figure 1The silicon tetrachloride outlets N8, N9, N10, and N11 shown are prone to blockage because the silicon tetrachloride liquid contains impurities after absorbing moisture from the aqueous hydrogen chloride. To facilitate the cleaning of internal impurities, a high-purity silicon tetrachloride inlet N3 is provided inside the bubbling tank 1, and a silicon tetrachloride drain port is provided at the bottom of the connecting pipe 2 above the valve.

[0048] The wire mesh plate 4 is used to separate liquid droplets entrained in the gas in the separation tower, especially mist droplets with a size of 3-5 micrometers. Through mechanisms such as collision, inertia, and interception, the droplets are captured and coalesced to fall, while the purified gas continues to flow. By removing hydrogen chloride droplets, the wire mesh plate 4 can reduce the material loss of silicon tetrachloride, ensure the relative purity of the hydrogen chloride gas after water removal, and reduce production costs.

[0049] Although silicon tetrachloride is recyclable in this application, to reduce the frequency of maintenance of the spray tank 3 and to ensure overall cleanliness of the equipment, this application preferably replaces the silicon tetrachloride periodically. The replaced silicon tetrachloride is then purified and reused. The advantage of providing a high-purity silicon tetrachloride inlet N3 in the bubbling tank 1 is that it facilitates the replenishment of silicon tetrachloride after periodic replacement. The high-purity silicon tetrachloride inlet N3 is initially closed, opened when feeding is needed, and closed after feeding is complete.

[0050] During maintenance, sufficient silicon tetrachloride is generally added through the silicon tetrachloride circulation inlet N4 or the high-purity silicon tetrachloride inlet N3. The amount of silicon tetrachloride should be sufficient to ensure that the silicon tetrachloride level in the spray tank 3 reaches about 90%, with a fluctuation of 5%-10% to ensure that the silicon tetrachloride can completely immerse the wire mesh plate 4. Adding directly through the silicon tetrachloride circulation inlet N4 is more convenient, as it can be added directly under pressure. When adding through the high-purity silicon tetrachloride inlet N3, it is necessary to store it first through the bubble tank 1. Then, the silicon tetrachloride is drawn through the silicon tetrachloride circulation outlet N2 and then through a pressurized device (which can be a circulating refrigeration component, but it is not refrigerating at this time) to the silicon tetrachloride circulation inlet N4, and then enters the spray tank 3. Although adding through the high-purity silicon tetrachloride inlet N3 is relatively troublesome, this method can also maintain a certain level in the bubble tank 1, thus having a certain cleaning effect on the bubble tank 1. However, in this case, both the bubble tank 1 and the spray tank 3 need to be stopped, that is, this operation can be performed in the idle state.

[0051] During maintenance without shutting down the system, the silicon tetrachloride can generally be added directly through the silicon tetrachloride circulation inlet N4 corresponding to the spray tank 3 under maintenance. After adding the material, the liquid level in the spray tank 3 reaches about 90% and is soaked for a certain period of time. Then, the silicon tetrachloride is discharged through the silicon tetrachloride outlets N8 to N11 corresponding to the spray tank 3. At the same time, since the liquid level in the spray tank 3 has reached about 90% at this time, the top of the isolation plate 7 is submerged in liquid. Therefore, liquid will also enter the connection pipe 2 to the ball valve 9. The liquid here can be discharged through the silicon tetrachloride drain ports N12 and N13.

[0052] like Figure 1 , 3 As shown, the bottom of the bubbling tank 1 is equipped with a base, which fixes the silicon tetrachloride circulation outlet N2. Inspection ports W1 and W2 and exhaust ports V1 to V4 are respectively provided on the upper and lower sides of the silicon tetrachloride circulation outlet N2. The top of the bubbling tank 1 is equipped with spare ports R1 and R2, wherein R1 preferably has a diameter of 50mm and R2 preferably has a size of 80mm. R1 is generally used as a spare inlet for silicon tetrachloride, and R2 is used as a spare outlet for silicon tetrachloride. Figure 1 The location of R1 is shown in the diagram. R2 is also usually located at the top of the bubbling tank 1, but it overlaps with R1 in the diagram and is therefore not shown. Inspection ports W1 and W2 can be used to check for blockages, flow rates, etc., in the silicon tetrachloride circulation outlet N2, while exhaust ports V1 to V4 can help relieve pressure when a large pressure is formed inside the bubbling tank 1.

[0053] like Figure 2 , Figure 3 As shown, both the spray tank 3 and the bubble tank 1 have inspection ports M located below the wire mesh plate 4 and below the bubble breaking plate 11, respectively. The inspection ports M can be found in [reference needed]. Figure 2 , Figure 3 The significance of setting the inspection port M below the wire mesh plate 4 / below the bubble breaking plate 11 is that hydrogen chloride gas generally moves upward. Therefore, when it forms gas-liquid entrainment, impurities usually accumulate at the bottom of the wire mesh plate 4 / bubble breaking plate 11. Thus, when manual cleaning is required, this setting makes it easier to clean the places where impurities are generated in the container.

[0054] During normal operation of this drying device, spray tank 3 is configured with one tank in operation and one in standby mode, i.e. Figure 1 The two ball valves 9 shown are one open and one closed. Their specific working principle is as follows:

[0055] (1) Hydrogen chloride containing water enters the bubbling tank 1 through the hydrogen chloride inlet N1. The liquid level in the bubbling tank 1 is controlled at 70% to ensure that the liquid level is higher than the hydrogen chloride inlet N1.

[0056] (2) After the bubbling hydrogen chloride comes into contact with the bubble-breaking plate 11, it is sent to the spray tank 3 (ball valve 9 is open) through the hydrogen chloride outlet N5. The spray tank 3 (ball valve 9 is closed) does not receive hydrogen chloride.

[0057] (3) The hydrogen chloride gas that has been initially dehydrated is discharged through the rain cap-type gas distributor 6 and comes into contact with the -20℃ circulating silicon tetrachloride sprayed by the spiral sprayer 10 to further remove the moisture in the hydrogen chloride gas. Then the hydrogen chloride gas passes through the wire mesh plate 4 and is sent out of the spray tank 3 through the hydrogen chloride outlet.

[0058] (4) The silicon tetrachloride liquid in the spray tank 3 flows into the bubbling tank 1 through the silicon tetrachloride outlet N8 to N11 and the silicon tetrachloride inlet N14-15. The silicon tetrachloride then passes through the silicon tetrachloride circulation outlet N2 and is processed by the circulation refrigeration component before being introduced into the silicon tetrachloride circulation inlet N4, thus completing the silicon tetrachloride circulation.

[0059] (5) During normal operation, there is no liquid level display in spray tank 3. If there is a liquid level display, it means that spray tank 3 is blocked and it is necessary to switch to another set of spray tank 3. During normal operation, the internal pressure of spray tank 3 is similar to that of bubbling tank 1. However, when blocked, the pressure in bubbling tank 1 is difficult to enter spray tank 3, making the pressure in bubbling tank 1 greater than the pressure in spray tank 3. After a certain degree, it is necessary to switch to another set of spray tank 3.

[0060] In some embodiments, a thermometer may also be provided to detect whether the internal temperature of the device is within a suitable range, for example... Figure 1 Both the T and T2 ports can be fitted with corresponding thermometers.

[0061] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A drying apparatus for silicon tetrachloride containing hydrated hydrogen chloride, characterized in that, It includes a bubbling tank and at least two spray tanks. Each of the spray tanks is connected to the bubbling tank via a connecting pipe. A valve is installed at each of the connecting pipes to control the connection status between the bubbling tank and each of the spray tanks. In the working state, the bubbling tank is connected to at least one of the spray tanks, and the connecting pipe between at least one of the spray tanks and the bubbling tank is closed.

2. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 1, characterized in that, The spray tank is equipped with a downward spray head; the spray tank is equipped with a level gauge, the lowest range of which is located below the spray head; the drying device is adapted to stop operating when the liquid level in the spray tank reaches the height of the level gauge and to switch the spray tank connected to the bubbling tank through a valve at the connecting pipe.

3. The drying apparatus for silicon tetrachloride containing aqueous hydrogen chloride as described in claim 1 or 2, characterized in that, Each of the spray tanks and each of the bubbling tanks is equipped with a pressure gauge. A wire mesh plate is provided in the upper middle part of the inner cavity of the spray tank. The pressure gauge is located above the wire mesh plate. The drying device is adapted to stop operating when the pressure in the bubbling tank exceeds the pressure setting range of any of the spray tanks and to switch the spray tanks connected to the bubbling tanks through the valve.

4. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 1, characterized in that, It also includes a silicon tetrachloride circulation inlet, a silicon tetrachloride discharge outlet, a silicon tetrachloride feed inlet, a silicon tetrachloride circulation outlet, and a circulation refrigeration component connected in sequence. The circulation refrigeration component is connected to the silicon tetrachloride circulation inlet so that liquid silicon tetrachloride passes through in sequence and forms a circulation. The silicon tetrachloride discharge outlet and the silicon tetrachloride circulation inlet are located on the spray tank, and the silicon tetrachloride feed inlet and the silicon tetrachloride circulation outlet are located on the bubbling tank.

5. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 4, characterized in that, The spray tank includes a hydrogen chloride inlet at the bottom and a hydrogen chloride outlet at the top. The bubbling tank has a water-containing hydrogen chloride inlet at the bottom and a water-containing hydrogen chloride outlet at the top. The hydrogen chloride inlet and the water-containing hydrogen chloride outlet are connected. An annular baffle plate is provided at the bottom of the inner cavity of the spray tank. The bottom inner cavity of the spray tank and the baffle plate are combined to form a liquid collecting cylinder. The annular inner cavity of the baffle plate covers the entire hydrogen chloride inlet. A gas dispersion structure is provided directly above the liquid collecting cylinder of the spray tank. A downward spraying nozzle is provided at a position in the inner cavity of the spray tank above the gas dispersion structure.

6. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 5, characterized in that, The gas dispersion structure is configured as a rain cap-type gas distributor, and the spray head is a spiral sprayer.

7. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 5, characterized in that, The inner cavity of the bubbling tank is equipped with a bubble-breaking plate, and the liquid level in the inner cavity of the bubbling tank is higher than the bubble-breaking plate and the water-containing hydrogen chloride inlet.

8. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 7, characterized in that, A wire mesh plate is provided in the upper middle part of the inner cavity of the spray tank, and the wire mesh plate is located above the spray head.

9. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 5, characterized in that, The bubbling tank is equipped with a high-purity silicon tetrachloride inlet, and the connecting pipe is equipped with a silicon tetrachloride drain port at its bottom and above the valve; the bottom of the bubbling tank is equipped with a base, which fixes the silicon tetrachloride circulation outlet, and an inspection port and an exhaust port are respectively provided on the upper and lower sides of the silicon tetrachloride circulation outlet; the top of the bubbling tank is equipped with a spare port.

10. The silicon tetrachloride drying apparatus containing aqueous hydrogen chloride as described in claim 8, characterized in that, The spray tank is provided with an inspection port below the wire mesh plate, and the bubble tank is provided with an inspection port below the bubble breaking plate.

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