Chlorosilane condensing apparatus and chlorosilane recovery system

Abstract

The application provides a chlorosilane condensing device and a chlorosilane recovery system. The chlorosilane condensing device is used for condensing chlorosilane contained in tail gas from an upstream process. The inner space of a shell is sequentially divided into a gas inlet area, a condensing area and a buffer area. A tail gas inlet is arranged on the shell and corresponds to the gas inlet area, and the tail gas inlet is used for inputting the tail gas into the gas inlet area. A liquid outlet is arranged on the shell and corresponds to the buffer area. A gas outlet is also arranged on the shell. A condensing pipe is arranged in the condensing area and is used for condensing the chlorosilane contained in the tail gas into liquid chlorosilane. The gas outlet is used for discharging the remaining gas which is not condensed into liquid after passing through the condensing pipe. The liquid outlet is used for discharging the liquid chlorosilane in the buffer area. The liquid chlorosilane condensed from the tail gas can be accumulated in the buffer area, and the volume of the buffer area is arranged to avoid poor liquid discharge of the liquid outlet, so as to avoid poor liquid discharge of the liquid outlet.

Description

Technical Field

[0001] This invention relates to the field of separation technology. Specifically, it relates to a chlorosilane condensation device and a chlorosilane recovery system. Background Technology

[0002] Chlorosilanes are an important raw material for the production of high-purity polysilicon. Currently, the reduction process, hydrogenation process, trichlorosilane synthesis process, and chlorosilane distillation purification process of polysilicon production systems all produce tail gas containing chlorosilanes. However, most manufacturers at home and abroad use the modified Siemens process to produce high-purity polysilicon.

[0003] In the modified Siemens process for polycrystalline silicon production, the reduction furnace generates a large amount of silicon tetrachloride as a byproduct. Silicon tetrachloride is currently typically converted using a cold hydrogenation process. In the cold hydrogenation process, the product gas from the fluidized bed reactor contains components such as microsilica powder, H2, SiHCl3, and SiCl4. After dust removal and washing, the product gas enters a series of sequentially connected condensers in a completely gaseous phase for staged condensation. This process cools the chlorosilanes (SiHCl3 and SiCl4) in the product gas into a liquid phase, while the H2 purity reaches over 99.5% and is then recycled by the compressor. The function of the condenser is to cool the chlorosilane-containing tail gas using a refrigerant. Since the condenser is connected to a chlorosilane storage tank, the liquid chlorosilane formed after condensation directly enters the chlorosilane storage tank through the condenser outlet.

[0004] However, the pipes connecting the condenser and the chlorosilane storage tank often experience poor drainage, leading to a significant increase in the amount of liquid chlorosilane after condensation. This substantial increase in liquid chlorosilane causes it to accumulate in the condenser, and may even result in it being entrained in subsequent condensers by the gas phase, increasing the heat load on those condensers and reducing their heat exchange efficiency. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a chlorosilane condensation device to avoid poor liquid flow at the outlet.

[0006] To achieve the objective of this invention, a chlorosilane condensation device is provided for condensing chlorosilane contained in tail gas from an upstream process. The condensation device includes: a shell, the inner space of which is sequentially divided into an inlet area, a condensation area, and a buffer area; wherein, a tail gas inlet is provided on the shell corresponding to the inlet area for inputting tail gas into the inlet area; a liquid outlet is provided on the shell corresponding to the buffer area; and a gas outlet is also provided on the shell; a condenser tube is provided in the condensation area for condensing the chlorosilane contained in the tail gas into liquid chlorosilane; wherein, the gas outlet is used to discharge any remaining gas that has not condensed into liquid after passing through the condenser tube; and the liquid outlet is used to discharge the liquid chlorosilane in the buffer area; the liquid chlorosilane formed by tail gas condensation can accumulate in the buffer area, and the volume of the buffer area is set to avoid obstruction of liquid flow from the liquid outlet.

[0007] Furthermore, the volume of the buffer zone is larger than the volume of the intake zone.

[0008] Furthermore, the outer shell includes: an upper shell; and a lower shell, the lower shell being used to form a buffer area, the lower shell being a cone shape that increases from top to bottom.

[0009] Furthermore, the outer shell includes: an upper shell; and a lower shell, the lower shell being used to form a buffer area, and the lower shell being spherical.

[0010] Furthermore, the inner space of the outer casing is also divided into an air outlet area, and an air outlet is provided on the outer casing corresponding to the air outlet area; the air outlet area and the air inlet area are arranged side by side, and both the air inlet area and the air outlet area are located above the condensation area; the condensation tube includes a first tube side located below the air inlet area and a second tube side located below the air outlet area. The first tube side is used to condense the chlorosilane contained in the exhaust gas entering the air inlet area into liquid chlorosilane, and the second tube side is used to condense the chlorosilane contained in the gas that has not condensed into liquid after the exhaust gas passes through the first tube side into liquid chlorosilane.

[0011] Furthermore, the upper shell is used to form the air intake area, condensation area, and air outlet area.

[0012] Furthermore, the condenser also includes a partition, disposed inside the upper housing, which is used to separate the air intake area and the air outlet area.

[0013] Furthermore, an air vent is provided on the outer casing corresponding to the buffer area.

[0014] Furthermore, the upper shell is used to form the intake area and the condensation area.

[0015] On the other hand, the present invention also provides a chlorosilane recovery system for recovering chlorosilane contained in the tail gas of polysilicon production. The chlorosilane recovery system includes: a chlorosilane condensation device provided in the above embodiments; and a storage device connected to the liquid outlet of the chlorosilane condensation device for storing liquid chlorosilane.

[0016] The present invention has the following beneficial effects:

[0017] The chlorosilane condensation device provided by this invention includes not only an inlet area for the exhaust gas and a condensation area for condensing the chlorosilanes in the exhaust gas, but also a buffer area to accommodate the liquid chlorosilanes formed by the condensation of the exhaust gas. By setting the volume of the buffer area, obstruction of liquid flow at the outlet can be avoided. Even if the amount of liquid chlorosilane formed after the exhaust gas condensation increases, the accumulated liquid chlorosilane in the buffer area will not cause obstruction of liquid flow at the outlet. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a structural schematic diagram of the chlorosilane condensation device according to the first embodiment of the present invention.

[0020] Figure 2 This is a structural schematic diagram of a chlorosilane condensation device according to the second embodiment of the present invention.

[0021] Figure 3 This is a structural schematic diagram of a chlorosilane condensation device according to the third embodiment of the present invention.

[0022] Figure 4 This is a structural schematic diagram of a chlorosilane condensation device according to the fourth embodiment of the present invention.

[0023] Figure 5 This is a structural schematic diagram of the chlorosilane recovery system according to the first embodiment of the present invention.

[0024] Figure 6 This is a structural schematic diagram of a chlorosilane recovery system according to the second embodiment of the present invention.

[0025] Figure 7 This is a structural schematic diagram of the chlorosilane recovery system according to the third embodiment of the present invention.

[0026] Figure 8 This is a structural schematic diagram of a chlorosilane condensation device in the prior art.

[0027] Explanation of key component symbols:

[0028] 10. Chlorosilane condensation device;

[0029] 100. Outer shell; 110. Exhaust gas inlet; 120. Liquid outlet; 130. Gas outlet; 140. Inlet area; 150. Condensation area; 160. Buffer area; 170. Upper shell; 180. Lower shell;

[0030] 190. Vent area;

[0031] 200. Condenser; 210. First tube pass; 220. Second tube pass;

[0032] 310. Liquid level measuring device; 320. First valve;

[0033] 410. Pressure detector; 420. Second valve;

[0034] 500, partition;

[0035] 30. Chlorosilane recovery system; 31. Storage device. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] Figure 8 This is a structural schematic diagram of a prior art chlorosilane condensation device. See also... Figure 8 In the prior art, the liquid chlorosilane formed after condensation in the chlorosilane condensation device leaves directly through the liquid outlet 120, which easily causes the liquid outlet 120 to have poor discharge. Therefore, in the embodiment of this application, a buffer area is added to the chlorosilane condensation device, and the volume of the buffer area is set to avoid poor discharge from the liquid outlet, so as to solve the problem of poor discharge that easily occurs in the prior art chlorosilane condensation device.

[0038] Figure 1 This is a structural schematic diagram of the chlorosilane condensation device 10 according to the first embodiment of the present invention. Figure 2 This is a structural schematic diagram of the chlorosilane condensation device 10 according to the second embodiment of the present invention. See also... Figure 1 and Figure 2A chlorosilane condenser 10 is used to condense chlorosilanes contained in the tail gas from the upstream process. The condenser 10 includes a housing 100 and a condenser tube 200. The internal space of the housing 100 is sequentially divided into an inlet region 140, a condensation region 150, and a buffer region 160. A tail gas inlet 110 is provided on the housing 100 corresponding to the inlet region 140, for introducing tail gas into the inlet region 140. A liquid outlet 120 is provided on the housing 100 corresponding to the buffer region 160. An outlet 130 is also provided on the housing 100. The condenser tube 200 is located in the condensation region 150 and is used to condense the chlorosilanes contained in the tail gas into liquid chlorosilanes. The outlet 130 is used to discharge any remaining gas that has not condensed into a liquid state after passing through the condenser tube 200. The liquid outlet 120 is used to discharge the liquid chlorosilanes in the buffer region 160. The liquid chlorosilane formed by the condensation of the exhaust gas can accumulate in the buffer zone 160, and the volume of the buffer zone 160 is set to prevent the liquid from flowing smoothly from the outlet 120.

[0039] Specifically, the exhaust gas from the upstream process enters the outer casing 100 through exhaust gas inlet 110, first reaching the intake area 140, and then passing through the condenser tube 200 in the condensation area 150. Under the action of the refrigerant in the condenser tube 200, the gaseous chlorosilanes contained in the exhaust gas release heat and condense into liquid chlorosilanes. In addition, the exhaust gas also contains residual gases, such as hydrogen, that have not condensed into liquid after passing through the condenser tube 200. The condensed liquid chlorosilanes and hydrogen enter the buffer area 160 together. The hydrogen leaves the chlorosilane condensation device 10 through the outlet 130, while the liquid chlorosilanes are temporarily stored in the buffer area 160 and leave the buffer area 160 through the liquid outlet 120.

[0040] In some embodiments, the volume of the buffer region 160 is related not only to the amount of exhaust gas supplied (the flow rate at the exhaust gas inlet 110), but also to the components in the exhaust gas and the condensation effect of the condenser tube 200.

[0041] Understandably, the relative positions of the intake region 140, the condensation region 150, and the buffer region 160 can be along... Figure 2 The X direction is set sequentially.

[0042] The chlorosilane condensation device 10 of this embodiment not only includes an inlet area 140 for the exhaust gas to enter and a condensation area 150 for condensing the chlorosilane in the exhaust gas, but also a buffer area 160 for accommodating the liquid chlorosilane formed by the condensation of the exhaust gas. By setting the volume of the buffer area 160 to prevent obstruction of liquid flow from the outlet, even if the amount of liquid chlorosilane formed after the exhaust gas condensation increases, the condensed liquid chlorosilane will accumulate in the buffer area 160 without obstructing the flow of liquid from the outlet 120.

[0043] Meanwhile, since liquid chlorosilane is stored in the buffer zone 160, the residual gas that has not condensed into liquid after passing through the condenser 200 can be prevented from leaving through the liquid outlet 120 and entering the storage device connected to the chlorosilane condenser 10.

[0044] See Figure 1 and Figure 2 The volume of the buffer zone 160 can be larger than the volume of the intake zone 140.

[0045] Specifically, the larger volume of the buffer region 160 than the intake region 140 can be achieved through the following embodiments. For example... Figure 3 and Figure 4 As shown, the outer casing 100 may include an upper casing 170 and a lower casing 180. In some embodiments, the minimum inner diameter of the lower casing 180 is still larger than the maximum inner diameter of the upper casing 170; in other words, the inner diameter of the lower casing 180 can be increased. In other embodiments, the inner diameter of the lower casing 180 is approximately equal to the inner diameter of the upper casing 170, while the length of the lower casing 180 is greater than the length of the upper casing 170. In other words, the length of the lower casing 180 can be increased so that the volume of the buffer region 160 inside the lower casing 180 is larger than the air intake region 140 of the upper casing 170.

[0046] See Figure 3 and Figure 4 The outer shell 100 includes an upper shell 170 and a lower shell 180. The lower shell 180 is used to form a buffer area 160, and the lower shell 180 is a cone shape that increases from top to bottom.

[0047] It is understandable that the cone-shaped structure is composed of a frustum, a cylinder, and a sphere in sequence, with the smallest outer diameter of the frustum facing the upper shell at 170°.

[0048] In other embodiments, the outer shell 100 includes an upper shell 170 and a lower shell 180. The lower shell 180 is used to form a buffer region 160, and the lower shell 180 is spherical.

[0049] See Figure 1 The inner space of the outer casing 100 is further divided into an air outlet area 190, and an air outlet 130 is provided on the outer casing 100 corresponding to the air outlet area 190. The air outlet area 190 and the air inlet area 140 are arranged side by side, and both the air inlet area 140 and the air outlet area 190 are located above the condensation area 150. The condensation pipe 200 includes a first pipe section 210 located below the air inlet area 140 and a second pipe section 220 located below the air outlet area 190. The first pipe section 210 is used to condense the chlorosilane contained in the exhaust gas entering the air inlet area 140 into liquid chlorosilane, and the second pipe section 220 is used to condense the chlorosilane contained in the gas that has not condensed into liquid after the exhaust gas passes through the first pipe section 210 into liquid chlorosilane.

[0050] It should be noted that the exhaust gas can pass through the first tube 210 and the second tube 220 in sequence. In other words, the condenser tube 200 performs secondary condensation on the exhaust gas, which can effectively reduce the content of gaseous chlorosilane in the residual gas discharged from the outlet.

[0051] Specifically, the upper shell 170 is used to form the air intake area 140, the condensation area 150, and the air outlet area 190.

[0052] Specifically, the condenser 10 also includes a baffle 500. The baffle 500 is disposed inside the upper housing 170 and is used to separate the air intake area 140 and the air outlet area 190.

[0053] It should be noted that the baffle 500 can be connected to the inner wall of the upper shell 170 to prevent exhaust gas from entering the exhaust area 190 directly from the intake area 140 without passing through the condensation area 150.

[0054] See Figure 2 An air outlet 130 is provided on the outer shell 100 corresponding to the buffer area 160.

[0055] Specifically, the upper shell 170 is used to form the intake area 140 and the condensation area 150.

[0056] In some embodiments, the exhaust gas inlet 110 may be located on the upper left side of the upper shell 170, the exhaust port 130 may be located on the upper right side of the lower shell 180, and the liquid outlet 120 may be located on the lower side of the lower shell 180.

[0057] In some embodiments, the upper shell 170 and the lower shell 180 are connected by a flange.

[0058] It is understandable that the upper shell 170 is provided with a first flange and the lower shell 180 is provided with a second flange. The connection between the upper shell 170 and the lower shell 180 is achieved through the connection of the first flange and the second flange, and the two flanges can be fixed together with bolts.

[0059] In other embodiments, the upper shell 170 and the lower shell 180 may also be connected by welding or by fasteners.

[0060] In other embodiments, the upper shell 170 and the lower shell 180 are integrally formed structures.

[0061] In some embodiments, the condensation device further includes a level measuring device 310 and a first valve 320. The level measuring device 310 is used to collect the real-time level of liquid chlorosilane in the buffer area 160. The first valve 320 is disposed at the outlet 120 and is connected to the level measuring device 310. The first valve 320 determines whether the real-time level of liquid chlorosilane collected by the level measuring device 310 is equal to a first preset value, and adjusts the flow rate of liquid chlorosilane at the outlet 120 when the real-time level is not equal to the first preset value.

[0062] In some embodiments, the real-time liquid level of liquid chlorosilane in the buffer area 160 collected by the level measuring device 310 can be transmitted to a display, and the operator can directly know the real-time liquid level of liquid chlorosilane accumulated in the chlorosilane condensing device 10 through the display, making the liquid chlorosilane in the chlorosilane condensing device 10 visible.

[0063] Specifically, the liquid level measuring device 310 can directly display the collected real-time liquid level to the operator via a monitor. The operator can then determine whether the real-time liquid level of the liquid chlorosilane collected by the liquid level measuring device 310 is equal to the first preset value. If the real-time liquid level is not equal to the first preset value, the operator can adjust the flow rate of the liquid chlorosilane at the outlet 120. This allows for visualization of the liquid chlorosilane level within the buffer area 160 of the condensation device 10, facilitating the operator to check and control the real-time liquid level of the liquid chlorosilane at any time.

[0064] It is understandable that when the real-time liquid level of the liquid chlorosilane in the buffer zone 160 is equal to the first preset value, the flow rate of the liquid chlorosilane at the outlet 120 is the first preset flow rate.

[0065] In some embodiments, when the real-time liquid level of liquid chlorosilane collected by the liquid level measuring device 310 exceeds the first preset value, the first valve 320 controls the flow rate of liquid chlorosilane at the outlet 120 to be greater than the first preset flow rate, so as to accelerate the speed at which liquid chlorosilane leaves the buffer area 160 and prevent excessive accumulation of liquid chlorosilane in the buffer area 160, or even reaching the outlet 130.

[0066] In other embodiments, when the real-time liquid level of the liquid chlorosilane collected by the liquid level measuring device 310 is lower than the first preset value, the first valve 320 controls the flow rate of the liquid chlorosilane from the outlet 120 to be less than the first preset flow rate, so as to slow down the speed at which the liquid chlorosilane leaves the buffer area 160, and prevent the liquid chlorosilane accumulated in the buffer area 160 from being too little or even the remaining gas from leaving through the outlet 120.

[0067] Figure 3 This is a structural schematic diagram of the chlorosilane condensation device 10 according to the third embodiment of the present invention. Figure 4 This is a structural schematic diagram of the chlorosilane condensation device 10 according to the fourth embodiment of the present invention. See also... Figure 3 and Figure 4The condensation device 10 also includes a level measuring device 310, a first valve 320, and a level controller. The level controller is connected to both the level measuring device 310 and the first valve 320. The level measuring device 310 sends real-time liquid level data to the level controller; the level controller determines whether the real-time liquid level of the liquid chlorosilane collected by the level measuring device 310 is equal to a first preset value, and if the real-time liquid level is not equal to the first preset value, controls the opening of the first valve 320 to adjust the flow rate of the liquid chlorosilane at the outlet 120.

[0068] Specifically, the level controller, level measuring device 310, and first valve 320 form a control loop to regulate the level of liquid chlorosilane in the buffer zone. When the real-time level of liquid chlorosilane in the buffer zone 160 is not equal to the first preset value, the first valve 320 controls the flow rate of liquid chlorosilane at the outlet 120 to cause the real-time level of liquid chlorosilane in the buffer zone 160 to drop rapidly or slowly. In other words, the opening degree of the first valve 320 is controlled by the real-time level of liquid chlorosilane in the buffer zone 160.

[0069] In some embodiments, the condensation device 10 further includes an on / off valve. The on / off valve is located at the exhaust gas inlet 110, and a level controller is also connected to the on / off valve. The level controller is further configured to determine whether the real-time liquid chlorosilane level collected by the level meter 310 is greater than or equal to a second preset value, and when the real-time liquid level is greater than or equal to the second preset value, control the on / off state of the on / off valve to stop the input of exhaust gas into the intake region 140. The second preset value is greater than a first preset value. When the real-time liquid chlorosilane level is equal to the second preset value, the liquid chlorosilane level in the buffer region 160 is at most at the lowest point of the outlet 130.

[0070] In other embodiments, an on / off valve may also be installed at the refrigerant inlet inside the condenser tube 200. The level controller is also used to determine whether the real-time liquid level of liquid chlorosilane collected by the level measuring device 310 is greater than or equal to a second preset value, and when the real-time liquid level is greater than or equal to the second preset value, to control the on / off of the on / off valve to stop the input of refrigerant to the refrigerant inlet, thereby preventing the tail gas from condensing to form liquid chlorosilane.

[0071] It is understandable that the lowest point of the liquid chlorosilane outlet 130 in the buffer zone 160 indicates that the liquid chlorosilane in the buffer zone 160 has not yet left the chlorosilane condenser 10 through the outlet 130.

[0072] When the real-time liquid level of the liquid chlorosilane is equal to the second preset value, the liquid level of the liquid chlorosilane in the buffer zone 160 can still be located 0.5m below the lowest point of the outlet 130.

[0073] This invention prevents the condensed liquid chlorosilane from being carried away from the chlorosilane condenser 10 by the exhaust gas through the outlet 130 by making the volume of the buffer zone 160 larger than that of the inlet zone 140. However, if the amount of liquid chlorosilane formed after the exhaust gas condenses increases rapidly in a short period of time, even if the opening of the first valve 320 is increased to allow the liquid chlorosilane to leave the buffer zone 160 quickly, if the real-time liquid level of the liquid chlorosilane still reaches the lowest point of the outlet 130, the input of exhaust gas into the inlet zone 140 is stopped, further preventing the liquid chlorosilane from being carried away from the chlorosilane condenser 10 by the exhaust gas through the outlet 130.

[0074] The condensation device also includes a pressure detector 410 and a second valve 420. The pressure detector 410 is used to collect the real-time pressure inside the housing 100. The second valve 420 is located at the gas outlet 130 and is connected to the pressure detector 410. The valve 420 determines whether the real-time pressure inside the housing 100 collected by the pressure detector 410 is greater than a third preset value, and adjusts the flow rate of the remaining gas at the gas outlet 130 when the real-time pressure is greater than the third preset value.

[0075] In some embodiments, the real-time pressure inside the housing 100 collected by the pressure detector 410 can be transmitted to a display, allowing staff to directly know the real-time pressure inside the housing 100, thus making the real-time pressure inside the housing 100 visible.

[0076] Specifically, the pressure detector 410 can directly display the collected real-time pressure to the operator via a monitor. The operator can then determine whether the real-time pressure inside the housing 100 collected by the pressure detector 410 is greater than a third preset value. If the real-time pressure is equal to the third preset value, the operator can adjust the flow rate of the remaining gas at the outlet 130. This allows for visualization of the real-time pressure inside the housing 100 of the condensing device 10, making it convenient for the operator to check and control the real-time pressure inside the housing 100 at any time.

[0077] It is understandable that when the real-time pressure inside the outer casing 100 is equal to the third preset value, the flow rate of the remaining gas at the outlet 130 is the second preset flow rate.

[0078] In some embodiments, when the real-time pressure inside the housing 100 is greater than a third preset value, the flow rate of the remaining gas at the outlet 130 is greater than a second preset flow rate, so as to accelerate the speed at which the remaining gas leaves the outlet 130, and avoid system pressure buildup or exhaust gas being unable to enter the intake area 140 through the exhaust gas inlet 110 or exhaust gas causing air blockage in the condensation area 150.

[0079] See Figure 3 and Figure 4The condensation device also includes a pressure detector 410, a second valve 420, and a pressure controller. The pressure controller is connected to both the pressure detector and the second valve. Specifically, the pressure controller determines whether the real-time pressure inside the housing, as collected by the pressure detector, exceeds a third preset value. If the real-time pressure exceeds the third preset value, the controller controls the opening of the second valve to regulate the flow rate of the remaining gas at the outlet.

[0080] In some embodiments, the first preset value, the second preset value, and the third preset value can be set in advance by staff.

[0081] Figure 5 This is a structural schematic diagram of the chlorosilane recovery system 30 according to the first embodiment of the present invention. Figure 6 This is a structural schematic diagram of the chlorosilane recovery system 30 according to the second embodiment of the present invention. See also... Figure 5 and Figure 6 The chlorosilane recovery system 30 is used to recover chlorosilanes contained in the tail gas of polysilicon production. The chlorosilane recovery system 30 includes a chlorosilane condenser 10 and a storage device 31, as described in any of the above embodiments. The storage device 31 is connected to the liquid outlet 120 of the chlorosilane condenser 10 and is used to store liquid chlorosilane.

[0082] Figure 7 This is a structural schematic diagram of the chlorosilane recovery system 30 according to the third embodiment of the present invention. See also... Figure 7 The chlorosilane recovery system 30 can also use multi-stage condensation to recover liquid chlorosilane and hydrogen, in order to avoid residual gaseous chlorosilane in the remaining gas leaving the outlet 130. The tail gas inlet 110 of the chlorosilane condensation unit 10 connected to the upstream process is used to supply tail gas into the inlet area 140, while the tail gas inlet 110 of the next stage condensation unit connected to the previous stage chlorosilane condensation unit is connected to the outlet 130 of the previous stage chlorosilane condensation unit.

[0083] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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 therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0084] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0085] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0086] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0087] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A chlorosilane condensing apparatus for condensing chlorosilane contained in an off-gas from an upstream process, characterized by, The condensation device includes: The outer casing has its internal space divided into an air intake area, a condensation area, and a buffer area. A tail gas inlet is provided on the outer casing corresponding to the air intake area, for introducing tail gas into the air intake area. A liquid outlet is provided on the outer casing corresponding to the buffer area. An air outlet is also provided on the outer casing. A condenser is provided in the condensation area. The condenser is used to condense the chlorosilane contained in the exhaust gas into liquid chlorosilane. The liquid chlorosilane formed by condensation and the remaining gas of the exhaust gas that has not condensed into liquid after passing through the condenser enter the buffer area together. The outer shell is provided with an air outlet corresponding to the buffer area. The air outlet is used to discharge the remaining gas that has not condensed into liquid after the exhaust gas passes through the condenser tube; the liquid outlet is used to discharge the liquid chlorosilane in the buffer area. The liquid chlorosilane formed by the condensation of the exhaust gas can accumulate in the buffer area, and the volume of the buffer area is set to prevent the liquid from flowing out of the outlet; the volume of the buffer area is larger than the volume of the air inlet area. The condensation device further includes a liquid level measuring device and a first valve. The liquid level measuring device is used to collect the real-time liquid level of liquid chlorosilane in the buffer area. The first valve is located at the liquid outlet and is connected to the liquid level measuring device. The device determines whether the real-time liquid level of liquid chlorosilane collected by the liquid level measuring device is equal to a first preset value, and adjusts the flow rate of liquid chlorosilane at the liquid outlet when the real-time liquid level is not equal to the first preset value. When the real-time liquid level of the liquid chlorosilane collected by the liquid level measuring device is lower than the first preset value, the first valve controls the flow rate of the liquid chlorosilane at the outlet to be less than the first preset flow rate.

2. The condensing apparatus according to claim 1, wherein The outer casing includes: Top shell; The lower shell, which forms the buffer area, is a cone-shaped structure that increases in size from top to bottom.

3. The condensation device according to claim 1, characterized in that, The outer casing includes: Top shell; The lower shell is used to form the buffer area, and the lower shell is spherical.

4. The condensation device according to claim 2 or 3, characterized in that, The upper shell is used to form the air intake area and the condensation area.

5. A chlorosilane recovery system for recovering chlorosilanes contained in the tail gas of polysilicon production, characterized in that, The chlorosilane recovery system includes: The chlorosilane condensation apparatus according to any one of claims 1 to 4; A storage device is connected to the outlet of the chlorosilane condenser, and the storage device is used to store the liquid chlorosilane.

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