Synthetic gas desorption and separation device

Abstract

The present invention discloses a synthetic material gas desorption and separation device, which relates to the technical field of polysilicon production. The main purpose is to desorb and recover hydrogen in the cold hydrogenation synthetic material before rectifying it. The main technical solution of the present invention is as follows: The synthetic material gas desorption and separation device includes: The lower end of a buffer tank is connected to one end of a feed pipe, and the other end of the feed pipe is connected to a rectifying tower; A synthetic material conveying pipe penetrates through the top wall of the buffer tank and is connected to a distribution pipe. The distribution pipe is arranged above the liquid level of the buffer tank, and a plurality of through holes are evenly distributed on the pipe wall of the distribution pipe; A condenser includes a mutually isolated first space and a second space. The first space is used for the flow of a refrigerant. The upper ends of the second space are respectively connected to one end of a recovery pipe and one end of a buffer pipe. The other end of the buffer pipe is connected to the upper end of the buffer tank. The lower end of the second space is connected to one end of a reflux pipe, and the other end of the reflux pipe penetrates through the top wall of the buffer tank and extends below the liquid level of the buffer tank.

Description

Technical Field

[0001] The present invention relates to the technical field of polysilicon production, and particularly to a desorption separation device for synthesis material gas. Background Art

[0002] In the process of producing polysilicon by the improved Siemens method, the synthesis material in the cold hydrogenation section is synthesized by reacting silicon powder, silicon tetrachloride, and hydrogen under high temperature and high pressure conditions. Under high pressure, a large amount of hydrogen is dissolved in the synthesis material. This part of the synthesis material is directly sent to the distillation column for separating components such as silicon tetrachloride, trichlorosilane, and dichlorodihydrogen silane. Since a large amount of hydrogen is dissolved in the synthesis material, desorption will occur in the distillation column, resulting in unstable operating pressure and large pressure relief in the distillation column, bringing difficulties to the operation of the distillation column. At the same time, the desorbed hydrogen enters the tail gas emission system and is not effectively recovered, causing waste, increasing production costs, and the difficulty of operating and controlling the distillation column. Summary of the Invention

[0003] In view of this, the present invention provides a desorption separation device for synthesis material gas, and the main purpose is to desorb and recover hydrogen in the cold hydrogenation synthesis material before distillation.

[0004] To achieve the above object, the present invention mainly provides the following technical solutions:

[0005] The present invention provides a desorption separation device for synthesis material gas, and the device includes: a buffer tank, a synthesis material conveying pipe, and a condenser;

[0006] The lower end of the buffer tank is connected to one end of a feeding pipe, and the other end of the feeding pipe is connected to a distillation column;

[0007] The synthesis material conveying pipe penetrates through the top wall of the buffer tank and is connected to a distribution pipe. The distribution pipe is arranged above the liquid level of the buffer tank, and a plurality of through holes are evenly distributed on the pipe wall of the distribution pipe;

[0008] The condenser includes a first space and a second space that are isolated from each other. The first space is used for the flow of refrigerant. The upper end of the second space is respectively connected to one end of a recovery pipe and one end of a buffer pipe. The other end of the buffer pipe is connected to the upper end of the buffer tank. The lower end of the second space is connected to one end of a reflux pipe, and the other end of the reflux pipe penetrates through the top wall of the buffer tank and extends below the liquid level of the buffer tank.

[0009] The object of the present invention and the technical problems to be solved can be further realized by adopting the following technical measures.

[0010] Optionally, the distribution pipe is annular and is horizontally arranged in the buffer tank.

[0011] Optionally, the condenser is a horizontal shell-and-tube heat exchanger, the first space is the tube side of the shell-and-tube heat exchanger, and the second space is the shell side of the shell-and-tube heat exchanger.

[0012] Optionally, it further includes a pressure sensor and a pressure regulating valve. The pressure sensor is installed at the upper end of the buffer tank, the pressure regulating valve is installed on the recovery pipe, and the pressure sensor and the pressure regulating valve are integrated into the DCS control system.

[0013] Optionally, it further includes a liquid level sensor and a liquid level regulating valve. The liquid level sensor is installed in the buffer tank, the liquid level regulating valve is installed on the feeding pipe, and the liquid level sensor and the liquid level regulating valve are integrated into the DCS control system.

[0014] Optionally, it further includes a purging pipe, which is connected to the upper end of the buffer tank.

[0015] Optionally, it further includes a control valve, which is installed on the purging pipe.

[0016] Optionally, the buffer tank adopts a spherical kettle.

[0017] By means of the above technical solution, the present invention has at least the following advantages:

[0018] The cold hydrogenation synthesis material is transported to the buffer tank through the synthesis material conveying pipe, and is sprayed out in a mist form through multiple through holes of the distribution pipe into the gas phase space of the buffer tank, which is beneficial to the dispersion of the synthesis material liquid droplets and the desorption of hydrogen in the synthesis material. The gas phase fluid in the buffer tank is transported to the second space of the condenser through the buffer pipe. Under the action of the refrigerant, the chlorosilane in the gas phase fluid is condensed and returned to the buffer tank through the reflux pipe, thereby realizing the gas-liquid separation of hydrogen and chlorosilane in the synthesis material.

[0019] Moreover, since the other end of the reflux pipe extends below the liquid level of the buffer tank, it avoids the gas phase fluid in the buffer tank from entering the reflux pipe, so that the buffer tank, the buffer pipe, the condenser and the reflux pipe form a path for chlorosilane condensation recovery, improving the efficiency of hydrogen and chlorosilane separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of a synthesis material gas desorption and separation device provided by an embodiment of the present invention.

[0021] The reference numerals in the accompanying drawings of the specification include: buffer tank 1, synthesis material conveying pipe 2, condenser 3, feeding pipe 4, distribution pipe 5, recovery pipe 6, buffer pipe 7, reflux pipe 8, pressure sensor 9, pressure regulating valve 10, liquid level sensor 11, liquid level regulating valve 12, transfer pump 13, purging pipe 14, control valve 15, first baffle 16, second baffle 17. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, elaborate in detail on the specific implementation manners, structures, features, and their effects of the application based on the present invention. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] As Figure 1 shown, a synthetic material gas desorption and separation device provided by an embodiment of the present invention includes: a buffer tank 1, a synthetic material conveying pipe 2, and a condenser 3;

[0025] The lower end of the buffer tank 1 is connected to one end of a feeding pipe 4, and the other end of the feeding pipe 4 is connected to a rectifying column;

[0026] The synthetic material conveying pipe 2 penetrates through the top wall of the buffer tank 1 and is connected to a distribution pipe 5. The distribution pipe 5 is arranged above the liquid level of the buffer tank 1, and a plurality of through holes are evenly distributed on the pipe wall of the distribution pipe 5;

[0027] The condenser 3 includes a first space and a second space that are isolated from each other. The first space is used for the flow of refrigerant. The upper end of the second space is respectively connected to one end of a recovery pipe 6 and one end of a buffer pipe 7. The other end of the buffer pipe 7 is connected to the upper end of the buffer tank 1. The lower end of the second space is connected to one end of a reflux pipe 8. The other end of the reflux pipe 8 penetrates through the top wall of the buffer tank 1 and extends below the liquid level of the buffer tank 1.

[0028] The working process of a synthetic material gas desorption and separation device is as follows:

[0029] The cold hydrogenated synthetic material is transported to the buffer tank 1 through the synthetic material conveying pipe 2 and is sprayed out in a mist form through the plurality of through holes of the distribution pipe 5 into the gas phase space of the buffer tank 1, which is beneficial to the dispersion of the synthetic material liquid droplets and the desorption of hydrogen in the synthetic material. The gas phase fluid in the buffer tank 1 is transported to the second space of the condenser 3 through the buffer pipe 7. Under the action of the refrigerant, the chlorosilane in the gas phase fluid is condensed and returned to the buffer tank 1 through the reflux pipe 8, thereby achieving the gas-liquid separation of hydrogen and chlorosilane in the synthetic material.

[0030] Moreover, because the other end of the reflux pipe 8 extends below the liquid level of the buffer tank 1, it prevents the gas phase fluid in the buffer tank 1 from entering the reflux pipe 8, thereby forming a path for the condensation and recovery of chlorosilane in the buffer tank 1, the buffer pipe 7, the condenser 3, and the reflux pipe 8, improving the efficiency of the separation of hydrogen and chlorosilane, and thus improving the efficiency of desorbing and recovering hydrogen.

[0031] Specifically, the refrigerant uses circulating water, 7°C water, and flowing air to condense the chlorosilane in the gaseous fluid entering the condenser 3.

[0032] Specifically, this device is used to desorb the hydrogen dissolved in the synthesis material during the production process in the cold hydrogenation section. The hydrogen returns to the cold hydrogenation section through the recovery pipe 6 for recycling, reducing the production cost.

[0033] Specifically, after the hydrogen is desorbed from the cold hydrogenation synthesis material, it is beneficial for the rectification separation in the subsequent section, ensuring the stability of the process parameters of the rectification column and the operation of the rectification column, and improving the purity of the chlorosilane separated by rectification.

[0034] Specifically, above the liquid level in the buffer tank 1, the synthesis material fluid is atomized and ejected through multiple through-holes of the distribution pipe 5, which is beneficial for the desorption of hydrogen.

[0035] Specifically, the pressure of the cold hydrogenation synthesis material pipe network is 2.5 MPa, and the temperature is about 60°C. The pressure of the buffer tank 1 is set to 0.20 - 0.30 MPa. In the buffer tank 1, due to the sudden decrease in pressure, a large amount of hydrogen dissolved in the chlorosilane is desorbed.

[0036] Specifically, the condenser 3 is located above the buffer tank 1.

[0037] As Figure 1 shown, in the specific embodiment, the distribution pipe 5 is annular, and the distribution pipe 5 is horizontally arranged in the buffer tank 1.

[0038] In this embodiment, specifically, the distribution pipe 5 is annular and horizontally arranged. On this basis, as long as the liquid level in the buffer tank 1 is controlled to be below the distribution pipe 5, the multiple through-holes on the distribution pipe 5 will not be submerged; moreover, the distribution pipe 5 is annular, enabling the pipe wall of the distribution pipe 5 to have as many through-holes as possible, ensuring the atomization degree of the synthesis material fluid and promoting the desorption of hydrogen.

[0039] As Figure 1 shown, in the specific embodiment, the condenser 3 is a horizontal shell-and-tube heat exchanger. The first space is the tube side of the shell-and-tube heat exchanger, and the second space is the shell side of the shell-and-tube heat exchanger.

[0040] In this embodiment, specifically, the travel length of the shell side is greater than the travel length of the tube side. The gaseous fluid to be condensed passes through the shell side of the horizontal shell-and-tube heat exchanger, with a longer residence time and a longer condensation time for the chlorosilane in the gaseous fluid, thereby improving the gas-liquid separation efficiency of hydrogen and chlorosilane and thus improving the desorption efficiency of hydrogen.

[0041] Specifically, a plurality of first baffles 16 and a plurality of second baffles 17 are provided in the shell side of the horizontal shell-and-tube heat exchanger. The first baffles 16 and the second baffles 17 are arranged alternately. Among them, the upper end of the first baffle 16 abuts against the top wall of the shell side of the horizontal shell-and-tube heat exchanger, and the lower end of the second baffle 17 abuts against the bottom wall of the shell side of the horizontal shell-and-tube heat exchanger. A through hole is provided at the lower end edge of the second baffle 17. During the operation of the device, the gas-phase fluid flows in a zigzag manner in the shell side of the horizontal shell-and-tube heat exchanger. The condensed chlorosilane settles at the bottom of the shell side and is concentrated into the reflux pipe 8 through the through hole, and then returns to the buffer tank 1.

[0042] Specifically, the condenser 3 can also be an air cooler.

[0043] As Figure 1 [[ID=^8]]shown, in the specific embodiment, it further includes a pressure sensor 9 and a pressure regulating valve 10. The pressure sensor 9 is installed at the upper end of the buffer tank 1, and the pressure regulating valve 10 is installed on the recovery pipe 6. The pressure sensor 9 and the pressure regulating valve 10 are integrated into the DCS control system.

[0044] In this embodiment, specifically, when the pressure sensor 9 detects that the air pressure in the buffer tank 1 is relatively high, the DCS controller issues an instruction to the pressure regulating valve 10 to increase the opening degree of the pressure regulating valve 10, so that the pressures in the second space of the condenser 3 and the buffer tank 1 are synchronously reduced to the set range, which is beneficial to the condensation recovery of the chlorosilane entrained in the hydrogen.

[0045] As Figure 1 shown, in the specific embodiment, it further includes a liquid level sensor 11 and a liquid level regulating valve 12. The liquid level sensor 11 is installed on the buffer tank 1, and the liquid level regulating valve 12 is installed on the feed pipe 4. The liquid level sensor 11 and the liquid level regulating valve 12 are integrated into the DCS control system.

[0046] In this embodiment, specifically, the liquid level sensor 11 uses a radar liquid level gauge and is set at the top of the buffer tank 1. When the liquid level sensor 11 detects that the liquid level in the buffer tank 1 is relatively high, the DCS controller issues an instruction to the liquid level regulating valve 12 to increase the opening degree of the liquid level regulating valve 12, so that the material in the buffer tank 1 is discharged quickly through the feed pipe 4, and the liquid level in the buffer tank 1 drops to the set range, ensuring that the liquid level is stable below the distribution pipe 5.

[0047] Specifically, it further includes a delivery pump 13. The inlet of the delivery pump 13 is connected to the lower end of the buffer tank 1, and the outlet of the delivery pump 13 is connected to the feed pipe 4, which is used to provide power for the discharge of the material in the buffer tank 1.

[0048] As Figure 1As shown, in the specific embodiment, it further includes a purge pipe 14, and the purge pipe 14 is connected to the upper end of the buffer tank 1.

[0049] In this embodiment, specifically, before the device is put into use or when maintenance is required, nitrogen is introduced into the buffer tank 1 through the purge pipe 14 to facilitate the replacement of the buffer tank 1 and ensure safety.

[0050] As Figure 1 shown, in the specific embodiment, it further includes a control valve 15, and the control valve 15 is installed on the purge pipe 14.

[0051] In this embodiment, specifically, the control valve 15 adopts a remote control valve 15. When a leak occurs in the buffer tank 1, the control valve 15 is remotely opened for nitrogen replacement.

[0052] As Figure 1 shown, in the specific embodiment, the buffer tank 1 adopts a spherical kettle.

[0053] In this embodiment, specifically, the spherical kettle has good pressure resistance, so that the buffer tank 1 has good compressive performance and reduces the probability of leakage of the buffer tank 1.

[0054] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present invention, and all should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A synthetic material gas desorption and separation device, characterized in that: include: A buffer tank, wherein the lower end of the buffer tank is connected to one end of a feed pipe, and the other end of the feed pipe is connected to a distillation tower; A synthetic material delivery pipe, which passes through the top wall of the buffer tank and is connected to a distribution pipe. The distribution pipe is arranged above the liquid level of the buffer tank, and the wall of the distribution pipe is uniformly distributed with a plurality of through holes; A condenser comprising a first space and a second space isolated from each other, the first space being used for the flow of refrigerant, the upper end of the second space being connected to one end of a recovery pipe and one end of a buffer pipe, respectively, the other end of the buffer pipe being connected to the upper end of the buffer tank, and the lower end of the second space being connected to one end of a return pipe, the other end of the return pipe penetrating the top wall of the buffer tank and extending below the liquid level of the buffer tank; Wherein, the condenser is located above the buffer tank.

2. The synthesis material gas desorption and separation device according to claim 1, characterized in that: The distribution pipe is annular and is horizontally arranged in the buffer tank.

3. The synthesis material gas desorption and separation device according to claim 1, characterized in that: The condenser is a horizontal shell and tube heat exchanger, the first space is the tube side of the shell and tube heat exchanger, and the second space is the shell side of the shell and tube heat exchanger.

4. The synthesis material gas desorption and separation device according to claim 1, characterized in that: It also includes a pressure sensor and a pressure regulating valve. The pressure sensor is installed at the upper end of the buffer tank, and the pressure regulating valve is installed at the recovery pipe. The pressure sensor and the pressure regulating valve are integrated into a DCS control system.

5. The synthesis material gas desorption and separation device according to claim 1, characterized in that: It also includes a liquid level sensor and a liquid level regulating valve. The liquid level sensor is installed on the buffer tank, and the liquid level regulating valve is installed on the feed pipe. The liquid level sensor and the liquid level regulating valve are integrated into a DCS control system.

6. The synthesis material gas desorption and separation device according to any one of claims 1 to 5, characterized in that: It also includes a purge pipe connected to the upper end of the buffer tank.

7. The synthesis material gas desorption and separation device according to claim 6, characterized in that: The device further comprises a control valve, which is installed on the purge pipe.

8. The synthesis material gas desorption and separation device according to any one of claims 1 to 5, characterized in that: The buffer tank adopts a spherical kettle.

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