Device and method for drying silicon tetrachloride containing water hydrogen chloride

Abstract

The silicon tetrachloride drying device comprises a bubbling tank and at least two spraying tanks, the spraying tanks are communicated with the bubbling tank through connecting pipelines, valves are arranged at the positions of the connecting pipelines so as to control the communication state of the bubbling tank and the spraying tanks, and the spraying tanks are communicated with the bubbling tank through the valves. And in a working state, the bubbling tank is communicated with at least one spraying tank, and the communicating pipeline between at least another spraying tank and the bubbling tank is closed. When the bubbling tank and the spraying tank which are separated from each other are blocked and the pressure difference between the spraying tank and the bubbling tank is increased, the drying device can still operate normally, only other standby spraying tanks need to be replaced, the blocked spraying tank is closed and stopped, the system does not need to be stopped for maintenance, and the operation efficiency of equipment is improved. And the stopped spraying tank can be independently cleaned and overhauled, and is reserved after the cleaning operation is completed.

Description

Technical Field

[0001] This application relates to the technical field of hydrogen chloride drying, and in particular to a silicon tetrachloride drying device for hydrogen chloride containing water. Background Art

[0002] When the existing drying tower for hydrogen chloride containing water conducts drying treatment, the hydrogen chloride containing water is sent to the silicon tetrachloride drying tower for drying and water removal. The hydrogen chloride contacts the silicon tetrachloride at -20°C sprayed from the top of the tower in a countercurrent manner. After removing the trace moisture carried by the hydrogen chloride, it is sent out from the top of the silicon tetrachloride drying tower, and the liquid level of the drying tower is maintained at 70%.

[0003] The internal components of the existing drying tower, namely the inlet for hydrogen chloride containing water, the silicon tetrachloride spray, and the wire mesh demister, are all in the same drying tower. After the silicon tetrachloride absorbs the moisture in the hydrogen chloride, silicic acid is formed, and through gas-liquid entrainment, the silicon tetrachloride spray nozzle and the wire mesh demister in the drying tower are prone to blockage, increasing the pressure difference between the inlet and outlet at the top of the tower. Due to the integrated design inside the drying tower, it will lead to system shutdown for maintenance. Summary of the Invention

[0004] The purpose of this application is to provide a silicon tetrachloride drying device for hydrogen chloride containing water that can be maintained without shutdown.

[0005] To achieve the above purpose, the technical solution adopted in this application is: a silicon tetrachloride drying device for hydrogen chloride containing water, including a bubbling tank and at least two spray tanks. Each of the spray tanks is connected to the bubbling tank through a connecting pipe, and a valve is provided at each connecting pipe to respectively control the connection state between the bubbling tank and each spray tank. In the working state, the bubbling tank is connected to at least one spray tank, and the connecting pipe between at least another spray tank and the bubbling tank is closed.

[0006] As a preference, the spray tank includes a hydrogen chloride inlet provided at the bottom and a hydrogen chloride outlet provided at the top. A spray head for downward spraying is provided inside the spray tank; a liquid level gauge is provided inside the spray tank, and the lowest range of the liquid level gauge is set below the spray head. The drying device is adapted to stop running when the liquid level in the spray tank reaches the height of the liquid level gauge, and switch the spray tank communicating with the bubbling tank through the valve.

[0007] As a preference, a pressure gauge is provided inside each spray tank and inside each bubbling tank. A wire mesh plate for preventing gas-liquid entrainment is provided in the upper middle part of the inner cavity of the spray tank, and the pressure gauge in the spray tank is provided above the wire mesh plate. The drying device is adapted to stop running when the pressure in the bubbling tank is greater than the set pressure range inside any spray tank, and switch the spray tank communicating with the bubbling tank through the valve.

[0008] As a preference, the drying device further includes a silicon tetrachloride circulation inlet, a silicon tetrachloride discharge port, a silicon tetrachloride feed port, a silicon tetrachloride circulation outlet, and a circulation refrigeration component that are connected in sequence. The circulation refrigeration component is connected to the silicon tetrachloride circulation inlet to enable liquid silicon tetrachloride to pass through in sequence and form a cycle. The silicon tetrachloride discharge port and the silicon tetrachloride circulation inlet are arranged on the spray tank, and the silicon tetrachloride feed port and the silicon tetrachloride circulation outlet are arranged on the bubbling tank.

[0009] As a preference, the bubbling tank is provided with a hydrogen chloride containing water feed port at the bottom and a hydrogen chloride containing water discharge port at the top. The hydrogen chloride inlet is connected to the hydrogen chloride containing water discharge port. An annular isolation plate is arranged at the bottom inner cavity of the spray tank. The bottom inner cavity of the spray tank and the isolation plate form a liquid collection cylinder together. The annular inner cavity of the isolation plate covers the entire hydrogen chloride inlet. The spray tank is provided with a gas dispersion structure directly above the liquid collection cylinder, and a spray head for downward spraying is arranged at a position in the spray tank inner cavity above the gas dispersion structure.

[0010] As a preference, the gas dispersion structure is set as a rain cap type gas distributor, and the spray head is a spiral sprayer.

[0011] As a preference, a bubble breaking plate is arranged in the inner cavity of the bubbling tank, and the liquid level in the inner cavity of the bubbler is higher than the bubble breaking plate and the hydrogen chloride containing water feed port; a wire mesh plate is arranged 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 preference, the bubbling tank is provided with a high purity silicon tetrachloride inlet, and a silicon tetrachloride drainage port is arranged at the bottom of the connecting pipe, above the valve.

[0013] As a preference, a base is arranged at the bottom of the bubbling tank. The base fixes the silicon tetrachloride circulation outlet, and an inspection port and an exhaust port are respectively arranged on the upper and lower sides of the silicon tetrachloride circulation outlet; a spare port is arranged at the top of the bubbling tank.

[0014] On the other hand, the present application proposes a method for drying hydrogen chloride containing water of the drying device. A liquid level gauge is arranged below the spraying position of the spray tank, and / or a pressure gauge is arranged in the bubbling tank. A wire mesh plate is arranged in the upper middle part of the inner cavity of the spray tank, and a pressure gauge is arranged above the wire mesh plate in the spray tank. The drying method includes: S1. Introduce the hydrogen chloride containing water to be treated into the bubbling tank containing silicon tetrachloride, where the liquid level of the silicon tetrachloride is not lower than the intake port of the hydrogen chloride containing water. S2, the bubbled aqueous hydrogen chloride enters at least one of the spray tanks from the bubbling tank, the aqueous hydrogen chloride is dried by spraying silicon tetrachloride in the spray tank, the silicon tetrachloride sprayed out of the spray tank is suitable for entering the bubbling tank, the silicon tetrachloride in the bubbling tank is suitable for entering the circulating refrigeration component through the silicon tetrachloride circulation outlet for cooling, and the cooled silicon tetrachloride enters the spray tank again for spraying; S3, emptying and replacing the silicon tetrachloride in the bubbling tank and the spray tank every 3-5 hours; S4, obtaining the pressure difference information between the spray tank and the bubbling tank according to the pressure gauge, and / or obtaining the liquid level information in the spray tank according to the liquid level gauge, obtaining the blockage information when the obtained pressure difference is greater than the set range or when the liquid level reaches the height of the liquid level gauge, and closing the valve of the spray tank corresponding to the blockage state according to the blockage information prompt, and opening the valve of at least another spray tank at the same time, so that the drying device maintains the working state without stopping; S5, passing high-purity silicon tetrachloride at 25° C. to 50° C., or silicon tetrachloride that has been filtered in the bubbling tank, into the spray tank in a blocked state, and making the liquid level in the spray tank reach or exceed the height of the wire mesh plate to wet and rinse the impurities and residues that cause the blockage, and emptying the silicon tetrachloride in the spray tank after soaking for a preset time; S6. After repeating step S4 three to five times, the spray tank is restored to standby.

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

[0016] The original integrated drying tower is divided into a split bubbling tank and a spray tank. When a blockage occurs and the pressure difference between the spray tank and the bubbling tank increases, the drying device can still operate normally. It only needs to replace the remaining spare spray tanks and shut down the blocked spray tank. There is no need to shut down the system for maintenance, which increases the operating efficiency of the equipment. The disabled spray tank can be cleaned and repaired separately and put into use after the cleaning operation is completed.

[0017] Through the set liquid level gauge, when impurities block the spray tank, it will affect the discharge of silicon tetrachloride in the spray tank. At this time, silicon tetrachloride accumulates in the spray tank and causes the liquid level to rise. When the liquid level reaches the liquid level gauge, a reading is obtained. At this time, it means that the liquid level has accumulated to a certain extent, indicating that maintenance is needed, so as to facilitate timely processing.

[0018] Through the pressure gauge set up, when blockage occurs, the hydrogen chloride gas in the bubbling tank is difficult to enter the spray tank through the blockage, so that the pressure of the spray tank above the blockage is significantly lower than the pressure in the bubbling tank. When the difference is greater than a certain range, it indicates that maintenance is needed and the pressure will not increase excessively, thereby facilitating timely processing. Brief Description of the Drawings

[0019] Figure 1 is a schematic diagram of the overall structure of an embodiment of the present application.

[0020] Figure 2 is Figure 1 a schematic diagram of the spray tank in

[0021] Figure 3 is Figure 1 a schematic diagram of the bubbling tank in

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

[0023] In the figure: 1. Bubbling tank; 2. Connecting pipeline; 3. Spray tank; 4. Wire mesh plate; 5. Spray rack; 6. Rain cap type gas distributor; 7. Partition board; 8. Fixed pressing plate; 9. Ball valve; 10. Spiral sprayer; 11. Foam breaking plate. Detailed Embodiments

[0024] Next, in combination with the detailed embodiments, the present application will be further described. It should be noted that on the premise of no conflict, the following described embodiments or technical features can be combined arbitrarily to form new embodiments.

[0025] In the description of the present application, it should be noted that for orientation terms, such as terms "center", "horizontal", "vertical", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation and position relationships indicated are based on the orientation or position relationships shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present application.

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

[0027] The terms "including" and "having" in the description and claims of the present application, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0028] See Figures 1 to 4As shown in the figure, the present application proposes a drying device for silicon tetrachloride containing hydrogen chloride, which includes a spraying tank 3 and a bubbling tank 1. One bubbling tank 1 is provided with a plurality of corresponding spraying tanks 3 and is connected through a connecting pipe 2. Valves are respectively arranged at the connection points of the connecting pipe 2 to respectively control the opening and closing. In the working state, one bubbling tank 1 is simultaneously connected to at least one spraying tank 3, and the connecting pipes corresponding to at least another spraying tank 3 are closed.

[0029] This drying device divides the originally integral drying tower into a split-type bubbling tank 1 and spraying tank 3. When a blockage occurs and the pressure difference between the spraying tank 3 and the bubbling tank 1 increases, this drying device can still operate normally. Only the remaining spare spraying tank 3 needs to be replaced, and the blocked spraying tank 3 is closed and deactivated. There is no need to stop the system for maintenance, which improves the operating efficiency of the equipment. The deactivated spraying tank 3 can be cleaned and repaired separately and be used as a spare after the cleaning operation is completed.

[0030] For the sake of easy understanding, in this embodiment, it is taken as an example that there is a total of one bubbling tank 1 and one bubbling tank 1 corresponds to two spraying tanks 3. At this time, the connecting pipe 2 is as Figure 4 shown, and it is actually a three-way pipe fitting.

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

[0032] The first one is to judge whether maintenance is needed by the liquid level at the bottom of the spraying tank 3. The spraying tank 3 includes a hydrogen chloride inlet arranged at the bottom and a hydrogen chloride outlet arranged at the top. A spray head for downward spraying is arranged inside the spraying tank 3; a liquid level gauge is arranged inside the spraying tank 3, and the lowest range of the liquid level gauge is set below the spray head. The drying device is adapted to stop operating when the liquid level in the spraying tank 3 reaches the height of the liquid level gauge, and switch the spraying tank 3 communicated with the bubbling tank 1 through a valve. The bubbling tank 1 is provided with a hydrogen chloride containing water inlet N1 below the liquid level and a hydrogen chloride containing water outlet N5 at its top. When impurities block inside the spraying tank 3, it will affect the discharge of silicon tetrachloride in the spraying tank 3. At this time, silicon tetrachloride accumulates in the spraying tank 3 and causes the liquid level to rise. When the liquid level reaches the liquid level gauge and a reading is obtained, it indicates that the liquid level has accumulated to a certain extent and maintenance is needed.

[0033] In this application, the minimum range of the liquid level gauge is set below the spray head instead of being higher or at the bottom of the spray tank 3. The reasons are as follows: (1) When spraying silicon tetrachloride, the spraying volume is relatively large, and it is inevitable that a certain amount of silicon tetrachloride accumulates at the bottom of the spray tank 3. Therefore, the bottom of the liquid level gauge is not set at the bottom of the spray tank 3; (2) At the same time, the liquid level gauge cannot be set too high. If it is set too high, too much silicon tetrachloride accumulates. After exceeding the spray head, the hydrogen chloride gas cannot be sprayed to remove water. Considering the above factors, in this application, the minimum range of the liquid level gauge is set at a certain distance below the spray head, so that maintenance can be prompted before the water cannot be removed by spraying, and this period also gives the operator enough time to react and operate. The liquid level gauge at this time corresponds to Figure 1 the liquid level gauge ports L5 and L8 in TL5 and TL8 in Figure 1 Of course, other liquid level gauges such as liquid level gauge ports L1, L2, L3, L4, L6, and L7 can also be set. The liquid level gauges at L6 and L7 can be used to detect the liquid level height in the spray tank 3, and they can be used when cleaning the spray tank 3; L1 and L2 can detect the liquid level height in the bubbling tank and can be used to detect the liquid level in the bubbling tank during the normal drying process.

[0034] The second method is to judge whether maintenance is required based on the pressure difference between the inside of the spray tank 3 and the inside of the bubbling tank 1. A pressure gauge is provided inside each spray tank 3 and inside each bubbling tank 1. The pressure gauge at the spray tank 3 is set above the easily blocked position (such as Figure 1 P2 and P3, mainly set at the top to detect the pressure. The pressure gauge in the bubbling tank 1 is set at the position of P1). The drying device is adapted to stop operating when the pressure in the bubbling tank 1 is greater than the pressure setting range inside any spray tank 3, and the spray tank 3 communicated with the bubbling tank 1 is switched through a valve. When the ball valve 9 is opened, the pressures inside the spray tank 3 and the bubbling tank 1 are generally the same or similar. When a blockage occurs inside the spray tank 3 (mainly the wire mesh plate 4, or it may also be the hydrogen chloride inlet), it is difficult for the hydrogen chloride gas in the bubbling tank 1 to enter the spray tank 3 through the blocked part (either cannot enter or becomes relatively difficult to enter). At this time, the pressure at the position above the blocked part in the spray tank 3 is significantly less than the pressure in the bubbling tank 1. When this difference is greater than 10 kPa, it generally indicates that maintenance is required. At this time, the wire mesh plate 4 is not completely blocked, so the pressure will not increase excessively, and the operator is prompted in advance to replace the spray tank 3 for maintenance without shutting down the machine. The above-mentioned pressure difference can be adjusted up and down according to actual needs, for example, adjusted to the range of 5 kPa - 15 kPa.

[0035] Obviously, the above two schemes can exist in this drying device at the same time, or can be set separately. When they exist at the same time, the one that reaches first is used as the standard for maintenance.

[0036] The material flow of this drying device mainly includes the following two aspects:

[0037] (1) The first is the overall direction of silicon tetrachloride. Silicon tetrachloride is a desiccant. In this embodiment, silicon tetrachloride is discharged from the bubbling tank 1 after drying the aqueous hydrogen chloride, and is returned to the equipment for recycling after cooling and impurity removal. Figure 1 , Figure 3 As shown, the drying device includes a silicon tetrachloride circulation inlet N4, silicon tetrachloride discharge ports N8-N11 (N8\N9 are Figure 2 The discharge port on the left side, N10 / N11 is Figure 2 The outlet on the right side), the silicon tetrachloride feed port N14-15 (the two spray tanks 3 correspond to N14 and N15 respectively), the silicon tetrachloride circulation outlet N2 and the 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, so that the liquid silicon tetrachloride passes through in sequence and forms a cycle, wherein the silicon tetrachloride outlets N8 to N11 and the silicon tetrachloride circulation inlet N4 are arranged on the spray tank 3, and the silicon tetrachloride feed port N14-15 and the silicon tetrachloride circulation outlet N2 are arranged on the bubbling tank 1. The above interfaces that are not directly connected are connected by setting pipelines.

[0038] (2) The second is the overall direction of aqueous hydrogen chloride. Aqueous hydrogen chloride enters from 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 the aqueous hydrogen chloride enters, it is bubbled in the liquid silicon tetrachloride to perform a preliminary drying treatment on the aqueous hydrogen chloride; then the aqueous hydrogen chloride with a portion of water removed enters the connecting pipe 2 from 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. Silicon tetrachloride liquid at about -20°C enters from the silicon tetrachloride circulation inlet N4 and is sprayed through the spray head, so that the hydrogen chloride and silicon tetrachloride are fully contacted in reverse, 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 an aqueous hydrogen chloride feed port N1 located at the bottom and an aqueous hydrogen chloride discharge port N5 located at the top, and the hydrogen chloride inlet (located at the bottom of the spray tank 3) is connected to the aqueous hydrogen chloride discharge port N5.

[0039] When overhauling and cleaning the silicon tetrachloride spray nozzle and the wire mesh plate 4, there is no need for water washing, alkali washing, etc., and the maintenance personnel do not need to enter the equipment for internal work. Only through the operation of flushing, soaking, draining and circulating high-purity silicon tetrachloride multiple times, the cleaning can be completed for standby. Of course, the principle that the present application can complete the cleaning through silicon tetrachloride is not only due to flushing and soaking, but also benefits from the timed replacement of silicon tetrachloride in this drying device. Generally, the silicon tetrachloride is replaced about every four hours. Through such an operation, the precipitate produced after the silicon tetrachloride absorbs water can be discharged regularly, reducing the accumulation time inside the equipment.

[0040] When replacing the silicon tetrachloride, stop feeding hydrogen chloride. The silicon tetrachloride is directly discharged at the N2 of the silicon tetrachloride circulation outlet and no longer enters the circulation refrigeration component for circulation. The spray tank 3 is emptied through the silicon tetrachloride discharge ports N8 to N11. During normal use, there is almost no silicon tetrachloride inside the connecting pipe 2. Therefore, generally no additional operation is required. After emptying, add high-purity silicon tetrachloride through the high-purity silicon tetrachloride inlet N3 to 70% of the liquid level of the bubbling tank 1.

[0041] In order to ensure that no silicon tetrachloride enters the connecting pipe 2, an annular isolation plate 7 is provided at the bottom inner cavity of the spray tank 3. The bottom inner cavity of the spray tank 3 and the isolation plate 7 form a liquid collecting cylinder. The annular inner cavity of the isolation plate 7 covers the entire hydrogen chloride inlet. The spray tank 3 is provided with a gas dispersion structure directly above the liquid collecting cylinder. A downward spraying spray head is provided at a position in the inner cavity of the spray tank 3 lower than the rain cap type gas distributor 6, and the spray head is higher than the gas dispersion structure.

[0042] The gas dispersion structure is preferably set as the rain cap type gas distributor 6, and the spray head is preferably set as the spiral sprayer 10. As Figure 2 shown, a spray rack 5 can be set up to install and fix the spiral sprayer 10, and the spray rack 10 is connected to the silicon tetrachloride circulation inlet N4. The rain cap type gas distributor 6 is as Figure 2 shown, and its cross-sectional projection is in the shape of a rain cap. Its specific structure is generally conical, such as conical. The significance of such a setting is that the rain cap type gas distributor can make the gas diffuse outward along the rain cap structure after being resisted. At this time, spraying silicon tetrachloride downward can make the gas-liquid fully contact, thus ensuring a better drying effect. For the corresponding hydrogen chloride gas containing water in this application, it goes from bottom to top, and the sprayed silicon tetrachloride liquid goes from top to bottom. Due to the guiding effect of the rain cap, the gas will decelerate and move upward along the inner cavity edge of the spray tank 3 relatively closely. When the spiral sprayer 10 preferably used in this application sprays, due to the spiral shape of the nozzle, the liquid often presents a conical shape during spraying, and the hydrogen chloride gas just fits this shape after being guided by the rain cap structure. Therefore, such a combination can greatly improve the utilization rate of the silicon tetrachloride liquid and also greatly improve the drying effect.

[0043] In some embodiments, the gas dispersion structure can also be other structures. For example, it can be set as a plate body with a number of uniformly distributed and relatively dense small holes formed thereon, so that the gas can be dispersed and discharged. However, this requires continuous gas discharge to prevent or reduce the spray liquid from entering the connecting pipe through these small holes or further entering the bubbling tank 1. Therefore, this is not a preferred solution.

[0044] As Figure 1 , Figure 3 shown, a foam-breaking plate 11 is provided in the inner cavity of the bubbling tank 1. During normal operation, the liquid level in the inner cavity of the bubbler is higher than the foam-breaking plate 11 and the feed port N1 for hydrogen chloride hydrate. The aperture of the foam-breaking plate 11 is relatively large, and its function is to reduce the gas-liquid entrainment effect when the hydrogen chloride gas forms bubbles after bubbling, the gas / mist formed by the volatilization of silicon tetrachloride itself, or the gas generated by bubbling passes through. Due to the relatively large viscosity and poor solubility of the silicic acid finally formed after silicon tetrachloride absorbs water, if a large amount enters the subsequent pipeline or the spray tank 3, impurities / wall scales will form and adhere at the flowing-through locations. It is relatively difficult to clean impurities in a closed pipeline. Therefore, it is necessary to reduce the generation of such impurities, and the provided foam-breaking plate 11 can effectively reduce the above-mentioned entrainment effect, thereby reducing the generation of impurity blockage / wall scales. Similarly, a wire mesh plate 4 is provided in the upper middle part of the inner cavity of the spray tank 3, and the wire mesh plate 4 is located above the spiral sprayer 10. The wire mesh plate 4 can also be called a wire mesh demisting plate. After the silicon tetrachloride sprayed and atomized by the spiral sprayer 10 comes into contact with the upward-moving hydrogen chloride gas, foam may also be generated. Such foam / bubbles will be discharged together during the upward movement of the gas, resulting in the material not being pure enough after discharging. Therefore, in this application, a wire mesh plate 4 with relatively small mesh holes is provided to prevent or reduce the entrainment of silicon tetrachloride or other impurities (such as silicic acid) by the dried hydrogen chloride.

[0045] The hydrogen chloride gas is in full contact with the silicon tetrachloride in the bubbling tank 1 in a bubbling manner, so that a preliminary water removal operation can be carried out. During this operation, due to the volatility of the silicon tetrachloride liquid and the gas-liquid entrainment of hydrogen chloride, hydrogen chloride gas will entrain silicon tetrachloride liquid and some "fog" will be generated due to the volatilization of silicon tetrachloride. By setting the foam-breaking plate 11, the gas-liquid entrainment and the volatilization loss of silicon tetrachloride can be reduced through principles such as collision and interception, thereby ensuring the purity of the hydrogen chloride discharged after preliminary treatment by the bubbling tank 1.

[0046] The wire mesh plate 4 is as Figure 2 shown. Since the wire mesh is generally made of relatively soft material, fixed pressing plates 8 can be provided at both the upper and lower ends for fixation. Such a fixation method preferably adopts a detachable installation method, so as to facilitate subsequent maintenance and replacement.

[0047] Obviously, during actual production, the above-mentioned wire mesh plate 4 and the bubble-breaking plate 11 are the places in the entire equipment where impurities are most likely to accumulate due to blocking gas-liquid entrainment. Especially for the wire mesh plate 4, its pore size is small, it has a stronger filtering effect on high-viscosity impurities, and it also has a higher adhesion to impurities. Therefore, the degree of blockage of the wire mesh plate 4 is usually relatively high. In addition, as Figure 1 shown by the silicon tetrachloride outlets N8, N9, N10, and N11, since the liquid of silicon tetrachloride will also entrain impurities after absorbing the moisture in the hydrogen chloride containing water, these outlets are also prone to blockage. In order to facilitate the cleaning of internal impurities, a high-purity silicon tetrachloride inlet N3 is provided in the bubbling tank 1, and a silicon tetrachloride drainage port is provided at the bottom of the connecting pipe 2, above the valve.

[0048] The wire mesh plate 4 provided is used to separate the liquid droplets entrained in the gas in the separation tower, especially the mist droplets with a size of 3-5 microns. Through mechanisms such as collision, inertia, and interception, the liquid droplets are captured and coalesced and fall, and the purified gas continues to flow. By removing the liquid droplets of hydrogen chloride, 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 the production cost.

[0049] Although the silicon tetrachloride in this application can be recycled, in order to reduce the maintenance frequency of the spray tank 3 and the overall cleanliness inside the equipment, it is preferred in this application to replace the silicon tetrachloride regularly, and the replaced silicon tetrachloride is purified and then reused. Then the advantage of setting the high-purity silicon tetrachloride inlet N3 in the bubbling tank 1 is that it is convenient to supplement the silicon tetrachloride in the equipment after regular replacement. The high-purity silicon tetrachloride inlet N3 is in a closed state initially and is opened when feeding is required and closed after feeding is completed.

[0050] During maintenance, generally, a sufficient amount of silicon tetrachloride needs to be 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 make the liquid level of silicon tetrachloride in the spray tank 3 reach about 90%, with a floating range of 5%-10% up and down, so that the silicon tetrachloride can completely immerse the wire mesh plate 4. It is more convenient to directly add the material through the silicon tetrachloride circulation inlet N4, and it can be directly added under pressure; when adding the material through the high-purity silicon tetrachloride inlet N3, it needs to be stored in the bubbling tank 1 first, and then the silicon tetrachloride is pumped to the silicon tetrachloride circulation inlet N4 through the silicon tetrachloride circulation outlet N2 by a pressurizing device (which can be a circulating refrigeration component, but it does not refrigerate at this time), and then enters the spray tank 3. Although adding the material through the high-purity silicon tetrachloride inlet N3 is relatively troublesome, in this way, there can also be a certain liquid level in the bubbling tank 1, so it also has a certain cleaning effect on the bubbling tank 1. However, at this time, both the bubbling tank 1 and the spray tank 3 need to be shut down, that is, this operation can be carried out when they are in an idle state.

[0051] Under the condition of maintenance without shutdown, generally, it can be directly fed through the silicon tetrachloride circulation inlet N4 corresponding to the spray tank 3 for maintenance. After feeding, the liquid level in the spray tank 3 reaches about 90% and soaks for a certain time. Subsequently, the silicon tetrachloride is discharged through the silicon tetrachloride outlet N8 to N11 corresponding to the spray tank 3. At the same time, since the liquid level in the spray tank 3 reaches about 90% at this time and the top of the isolation plate 7 is submerged by the liquid, the 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] As Figure 1 , 3 shown, a base is provided at the bottom of the bubbling tank 1. The base fixes the silicon tetrachloride circulation outlet N2, and 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; spare ports R1 and R2 are provided at the top of the bubbling tank 1. Among them, the diameter of R1 is preferably 50 mm, and the size of R2 is preferably 80 mm. R1 is generally used as the spare inlet for silicon tetrachloride, and R2 is used as the spare outlet for silicon tetrachloride. Figure 1 The position of R1 is shown in

[0053] As Figure 2 , Figure 3 shown, a maintenance port M is provided below the wire mesh plate 4 of the spray tank 3 and below the bubble-breaking plate 11 of the bubbling tank 1. The maintenance port M can refer to Figure 2 , Figure 3 . The significance of setting the maintenance port M correspondingly below the wire mesh plate 4 / below the bubble-breaking plate 11 is that hydrogen chloride gas generally moves upward. Therefore, when gas-liquid entrainment and other effects are formed, impurities usually accumulate at the bottom of the wire mesh plate 4 / bubble-breaking plate 11. Therefore, when manual cleaning is required, such a setting is more convenient for cleaning the places where impurities are generated in the container.

[0054] When this drying device operates normally, one of the two spray tanks 3 is in use and the other is in standby, that is, as Figure 1 shown, one of the two ball valves 9 is open and the other is closed. Its specific working principle is as follows:

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

[0056] (2) After the bubbled hydrogen chloride contacts the bubble-breaking plate 11, it is sent to the spray tank 3 (the ball valve 9 is open) through the hydrogen chloride outlet N5, and the spray tank 3 (the ball valve 9 is closed) does not receive hydrogen chloride.

[0057] (3) The preliminarily dehydrated hydrogen chloride is led out through the rain hat type gas distributor 6 and contacts with the -20°C recycled 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 discharge port.

[0058] (4) The silicon tetrachloride liquid in the spray tank 3 flows from the silicon tetrachloride discharge ports N8 to N11 into the silicon tetrachloride inlet N14 - 15 of the bubbling tank 1 through the silicon tetrachloride inlet of the bubbling tank 1. Then, the silicon tetrachloride is introduced into the silicon tetrachloride circulation inlet N4 after being processed by the circulation refrigeration assembly through the silicon tetrachloride circulation outlet N2, thus completing the silicon tetrachloride circulation.

[0059] (5) During normal operation, there is no liquid level display in the spray tank 3. If there is a liquid level display, it indicates that the spray tank 3 is blocked and another set of spray tank 3 needs to be switched to operate. During normal operation, the pressure in the spray tank 3 is similar to the pressure in the bubbling tank 1. When blocked, it is difficult for the pressure in the bubbling tank 1 to enter the spray tank 3, resulting in the pressure in the bubbling tank 1 being greater than the pressure in the spray tank 3. After exceeding a certain degree, another set of spray tank 3 needs to be switched to operate.

[0060] In some embodiments, a thermometer can also be set to detect whether the temperature inside the device is within a suitable range. For example Figure 1 thermometers corresponding to them can be installed at both the T and T2 ports in

[0061] The present application also proposes a drying method for a silicon tetrachloride drying device for hydrogen chloride containing water. A liquid level gauge is provided below the spraying position in the spray tank 3, and / or a pressure gauge is provided inside the bubbling tank 1. A wire mesh plate 4 is provided in the upper middle part of the inner cavity of the spray tank 3. A pressure gauge is provided above the easily blocked wire mesh plate 4 in the spray tank 3. The drying method mainly includes:

[0062] S1. Introduce the hydrogen chloride containing water to be processed into the bubbling tank 1 filled with silicon tetrachloride, where the liquid level of the silicon tetrachloride is not lower than the inlet of the hydrogen chloride containing water.

[0063] S2. The bubbled hydrogen chloride containing water enters at least one spray tank 3 from the bubbling tank 1. In the spray tank 3, the hydrogen chloride containing water is dried by spraying silicon tetrachloride. The silicon tetrachloride sprayed in the spray tank 3 is suitable for entering the bubbling tank 1. The silicon tetrachloride in the bubbling tank 1 is suitable for being discharged and a circulation refrigeration assembly is set to cool it down. The cooled silicon tetrachloride enters the spray tank 3 again for spraying.

[0064] S3. Drain and replace the silicon tetrachloride in the bubbling tank 1 and the spray tank 3 every 3 - 5 hours. Preferably, it is every 4 hours.

[0065] S4. Obtain the pressure difference information between the spray tank 3 and the bubbling tank 1 according to the pressure gauge, and / or obtain the liquid level information in the spray tank 3 according to the liquid level gauge, obtain blockage information when the obtained pressure difference is greater than the set range or the liquid level reaches the height of the liquid level gauge, and close the valve of the spray tank 3 corresponding to the blocked state according to the blockage information, and open the valve of at least another spray tank 3 at the same time to keep the drying device in a non-stop working state.

[0066] S5. Pass high-purity silicon tetrachloride at 25℃~50℃ or filtered silicon tetrachloride in the bubbling tank into the blocked spray tank, and make the liquid level in the spray tank reach or exceed the height of the wire mesh plate to soak and rinse the impurities and residues that cause the blockage. After soaking for a preset time, empty the silicon tetrachloride in the spray tank. Soaking helps the impurities and residues to soften, heat up and fall off, and the impurities and residues are taken away with the emptying of silicon tetrachloride.

[0067] S6. After repeating step S5 three to five times, the spray tank 3 is restored to standby.

[0068] In step S5, the temperature range of high-purity silicon tetrachloride is selected to be 25°C to 50°C, and silicon tetrachloride is rinsed at room temperature or slightly higher temperature. Since the silicon tetrachloride used for hydrogen chloride drying reacts with water to produce silicic acid precipitate and hydrogen chloride gas, which is an exothermic reaction, the temperature of the silicon tetrachloride itself used for recycling after drying increases. Generally speaking, the silicon tetrachloride needs to be cooled to about -20°C before entering the spray tank 3 for spraying. During the maintenance process, the temperature of the silicon tetrachloride used in the previous production increases significantly. Of course, the circulation flow rate of the silicon tetrachloride in the spray tank 3 will be controlled during actual production, so that the silicon tetrachloride can be controlled to enter the circulation after refrigeration, thereby preventing the spray tank from 3 is vaporized, so in fact, the temperature of the controlled silicon tetrachloride after drying with hydrogen chloride gas can generally be raised to 30°C to 55°C (lower than the boiling point of 57.6°C), and since the above reaction does not reduce the concentration of silicon tetrachloride, the silicon tetrachloride can be used to directly rinse the spray tank 3 after simple filtration (the temperature of silicon tetrachloride in this process is slightly reduced to about 25°C to 50°C); obviously, the viscosity of the silicic acid precipitate produced by drying hydrogen chloride gas with silicon tetrachloride is relatively large, but the viscosity of silicic acid has the characteristics of increasing fluidity with increasing temperature, so when using silicon tetrachloride at room temperature or slightly higher temperature for rinsing, the adhesion of silicic acid can be reduced, thereby making the rinsing effect better. Generally, the temperature of silicon tetrachloride is relatively high when it flows into the bubbling tank 1 from the spray tank 3 after the reaction, for example, 45°C. After multiple rinsing and emptying steps, its temperature can still be maintained at about 25°C, so the use of the silicon tetrachloride does not require additional heating treatment.

[0069] The purity of the silicon tetrachloride used for rinsing in step S5 is 95-99% (mass fraction), preferably 98%. The higher the purity, the better, but the corresponding cost will increase significantly with the increase in purity.

[0070] In step S5 during soaking, the liquid level height in the spray tank 3 is 70%-95%, preferably 90%. When the liquid level height is too low, the distance from the liquid level to the blockage position is short, and the flow contact time between the silicon tetrachloride and the blockage position is relatively short. The silicon tetrachloride will act on the blockage position both when added and discharged. Therefore, relatively increasing the liquid level of the added silicon tetrachloride can act on the blockage position twice during the addition and emptying processes, greatly improving the rinsing effect. Since the silicon tetrachloride used for rinsing generally does not undergo chemical reactions, it can be reused after simple filtration, and the cost will not increase significantly. However, the liquid level height should not be too high, otherwise the liquid level reaching the top may bring in and adhere some impurity residues to the top of the spray tank 3, making it difficult to clean later.

[0071] In step S5, the soaking time range is 30s - 60s, so that the temperature of the impurity residues at the blockage position is fully increased to reduce their viscosity, and then rinsing is carried out, which helps to improve the rinsing effect.

[0072] In step S6, the preferred number of repetitions is four times.

[0073] The above describes the basic principle, main features and advantages of the present application. Those skilled in the art of this industry should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A silicon tetrachloride drying device for hydrogen chloride containing water, characterized in that, It includes a bubbling tank and at least two spray tanks. Each of the spray tanks is communicated with the bubbling tank through a connecting pipeline, and a valve is arranged at each connecting pipeline to respectively control the communication state between the bubbling tank and each spray tank. In the working state, the bubbling tank is communicated with at least one spray tank, and the connecting pipeline between at least another spray tank and the bubbling tank is closed.

2. The silicon tetrachloride drying device for hydrogen chloride hydrate according to claim 1, characterized in that, A spray head for downward spraying is arranged inside the spray tank; a liquid level gauge is arranged in the spray tank, and the lowest range of the liquid level gauge is arranged 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 liquid level gauge and switch the spray tank communicated with the bubbling tank through the valve at the connecting pipeline.

3. The silicon tetrachloride drying device for hydrogen chloride hydrate according to claim 1 or 2, characterized in that, A pressure gauge is arranged inside each spray tank and inside each bubbling tank. A wire mesh plate is arranged in the upper middle part of the inner cavity of the spray tank, and the pressure gauge is arranged above the wire mesh plate. The drying device is adapted to stop operating when the pressure in the bubbling tank is greater than the set pressure range inside any spray tank and switch the spray tank communicated with the bubbling tank through the valve.

4. The silicon tetrachloride drying device for hydrogen chloride hydrate according to claim 1, characterized in that, It further includes a silicon tetrachloride circulation inlet, a silicon tetrachloride discharge port, a silicon tetrachloride feed port, a silicon tetrachloride circulation outlet and a circulation refrigeration component which are communicated in sequence. The circulation refrigeration component is communicated with the silicon tetrachloride circulation inlet to enable liquid silicon tetrachloride to pass through in sequence and form a circulation. The silicon tetrachloride discharge port and the silicon tetrachloride circulation inlet are arranged on the spray tank, and the silicon tetrachloride feed port and the silicon tetrachloride circulation outlet are arranged on the bubbling tank.

5. The silicon tetrachloride drying device for hydrogen chloride hydrate according to claim 4, characterized in that, The spray tank includes a hydrogen chloride inlet arranged at the bottom and a hydrogen chloride outlet arranged at the top. The bubbling tank is provided with a water-containing hydrogen chloride feed port at the bottom and a water-containing hydrogen chloride discharge port at the top. The hydrogen chloride inlet is communicated with the water-containing hydrogen chloride discharge port. An annular isolation plate is arranged at the bottom inner cavity of the spray tank. The bottom inner cavity of the spray tank and the isolation plate form a liquid collection cylinder together. The annular inner cavity of the isolation plate covers the entire hydrogen chloride inlet. A gas dispersion structure is arranged directly above the liquid collection cylinder in the spray tank, and a spray head for downward spraying is arranged at a position in the inner cavity of the spray tank higher than the gas dispersion structure.

6. The silicon tetrachloride drying device for hydrogen chloride hydrate according to claim 5, characterized in that, The gas dispersion structure is set as a rain cap type gas distributor, and the spray head is a spiral sprayer.

7. The silicon tetrachloride drying device for hydrogen chloride hydrate according to claim 5, characterized in that, A bubble breaking plate is arranged in the inner cavity of the bubbling tank, and the liquid level in the inner cavity of the bubbling device is higher than the bubble breaking plate and the water-containing hydrogen chloride feed port.

8. The silicon tetrachloride drying device containing hydrogen chloride in water according to claim 5, characterized in that, A wire mesh plate is arranged 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 device for hydrogen chloride hydrate according to claim 1 or 5, characterized in that, The bubbling tank is provided with a high-purity silicon tetrachloride inlet. The connecting pipeline is provided with a silicon tetrachloride drainage port at a position at its bottom and above the valve; a base is arranged at the bottom of the bubbling tank. The base fixes the silicon tetrachloride circulation outlet, and an inspection port and an exhaust port are respectively arranged on the upper and lower sides of the silicon tetrachloride circulation outlet; a spare port is arranged at the top of the bubbling tank.

10. A method for drying water-containing hydrogen chloride by using the drying device according to any one of claims 1-9, characterized in that The spray tank is provided with a liquid level gauge below the spray position, and / or the bubbling tank is provided with a pressure gauge, a wire mesh plate for preventing gas-liquid entrainment is provided in the middle and upper part of the inner cavity of the spray tank, and the spray tank is provided with a pressure gauge above the wire mesh plate, and the drying method comprises: S1, passing the aqueous hydrogen chloride to be treated into the bubbling tank containing silicon tetrachloride, wherein the liquid level of silicon tetrachloride is not lower than the air inlet of the aqueous hydrogen chloride; S2, the bubbled aqueous hydrogen chloride enters at least one of the spray tanks from the bubbling tank, the aqueous hydrogen chloride is dried by spraying silicon tetrachloride in the spray tank, the silicon tetrachloride sprayed out of the spray tank is suitable for entering the bubbling tank, the silicon tetrachloride in the bubbling tank is suitable for being discharged and a circulating refrigeration component is set for cooling, and the cooled silicon tetrachloride enters the spray tank again for spraying; S3, emptying and replacing the silicon tetrachloride in the bubbling tank and the spray tank every 3-5 hours; S4, obtaining the pressure difference information between the spray tank and the bubbling tank according to the pressure gauge, and / or obtaining the liquid level information in the spray tank according to the liquid level gauge, obtaining the blockage information when the obtained pressure difference is greater than the set range or when the liquid level reaches the height of the liquid level gauge, and closing the valve of the spray tank corresponding to the blockage state according to the blockage information prompt, and opening the valve of at least another spray tank at the same time, so that the drying device maintains the working state without stopping; S5, passing high-purity silicon tetrachloride at 25° C. to 50° C., or silicon tetrachloride that has been filtered in the bubbling tank, into the spray tank in a blocked state, and making the liquid level in the spray tank reach or exceed the height of the wire mesh plate to wet and rinse the impurities and residues that cause the blockage, and emptying the silicon tetrachloride in the spray tank after soaking for a preset time; S6. After repeating step S4 three to five times, the spray tank is restored to standby.

Images