Adsorption system for removing boron from trichlorosilane

Abstract

The utility model discloses an adsorption system for removing boron from trichlorosilane. The adsorption system comprises a silicon tetrachloride raw material tank, a feeding tank and an adsorption column, the silicon tetrachloride raw material tank, the feeding tank and the adsorption column are sequentially communicated through a pipeline; a pressure pump is arranged on a pipeline between the silicon tetrachloride raw material tank and the feeding tank, and is used for conveying silicon tetrachloride in the silicon tetrachloride raw material tank into the feeding tank; the feeding tank is externally connected with a nitrogen tank through a pipeline, and the nitrogen tank conveys nitrogen to the feeding tank; the feeding tank is used for mixing the nitrogen and the silicon tetrachloride and then conveying the mixture to the adsorption column; the adsorption column is provided with a tail gas discharge port, and the tail gas discharge port is communicated with the tail gas treatment device through a pipeline; the gel is activated in a nitrogen-assisted blowing automatic intermittent feeding manner, so that the temperature of the adsorption column is controlled, and the danger is greatly reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of trichlorosilane boron removal, and in particular relates to an adsorption system for trichlorosilane boron removal. Background Art

[0002] Polysilicon is an important raw material for large-scale integrated circuits and the photovoltaic industry. The main polysilicon production process is the silane fluidized bed method, which requires the use of the raw material trichlorosilane. Currently, after trichlorosilane is produced through the cold hydrogenation process, the trichlorosilane product enters the boron removal device for impurity removal, and the boron element is adsorbed by the adsorption column to reduce the boron content of the product to 10ppm. In the prior art, as the life of the adsorbent gel in the adsorption column decreases, the gel needs to be replaced regularly. After the gel is replaced, the gel needs to be activated with silicon tetrachloride. The activation process releases a lot of heat, and the temperature and pressure rise sharply, which increases the danger. In addition, the temperature rises too quickly during the gel activation process, and the gel is easily deactivated at high temperature, which greatly reduces the adsorption effect of the gel. After being put into use, it will not be able to adsorb the boron element in the product trichlorosilane due to insufficient activation or gel inactivation, affecting the boron removal effect, thereby further affecting the quality of downstream silicon materials. Utility Model Content

[0003] The utility model aims to provide an adsorption system for trichlorosilane boron removal, which activates gel by nitrogen-assisted automatic intermittent feeding, controls the temperature of the adsorption column, greatly reduces the risk, fully stimulates gel activity, improves gel adsorption capacity, and thus improves product quality.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is:

[0005] An adsorption system for removing boron from trichlorosilane, comprising a silicon tetrachloride raw material tank, a feeding tank and an adsorption column; the silicon tetrachloride raw material tank, the feeding tank and the adsorption column are sequentially connected through a pipeline; a pressure pump is arranged on the pipeline between the silicon tetrachloride raw material tank and the feeding tank, and the pressure pump transports the silicon tetrachloride in the silicon tetrachloride raw material tank into the feeding tank;

[0006] The feeding tank is connected to a nitrogen tank through a pipeline, and the nitrogen tank transports nitrogen to the feeding tank; the feeding tank mixes the nitrogen and silicon tetrachloride and transports them to the adsorption column; the adsorption column is provided with a tail gas discharge port, and the tail gas discharge port is connected to the tail gas treatment device through a pipeline.

[0007] Preferably, a first solenoid valve is provided on the pipeline between the silicon tetrachloride raw material tank and the feeding tank; a second solenoid valve is provided on the pipeline between the nitrogen tank and the feeding tank; a third solenoid valve is provided on the pipeline between the feeding tank and the adsorption column; the first solenoid valve, the second solenoid valve, the third solenoid valve and the pressure pump are electrically connected to the controller.

[0008] Preferably, a pressure sensor is arranged in the feeding tank; a plurality of temperature sensors are evenly arranged on the side wall of the adsorption column along the vertical direction; and the pressure sensor and the temperature sensor are electrically connected to the controller.

[0009] Preferably, a fourth solenoid valve and a pressure gauge are provided on the pipeline between the exhaust gas discharge port and the exhaust gas treatment device; the fourth solenoid valve and the pressure gauge are electrically connected to the controller.

[0010] Preferably, a mixing area is provided in the feeding tank; a spray pipe is provided on the top of the mixing area; the spray pipe is connected to the silicon tetrachloride raw material tank through a first feeding pipe; a plurality of atomizing nozzles are provided on the spray pipe; the atomizing nozzles spray silicon tetrachloride downwards;

[0011] The bottom of the mixing area is provided with a jet assembly, and the jet assembly includes a jet main pipe; the jet main pipe is connected to the nitrogen tank through a second feed pipe; the jet main pipe is connected to a plurality of jet branch pipes; a plurality of gas nozzles are evenly distributed on the jet main pipe and the jet branch pipes, and the plurality of gas nozzles spray nitrogen upwards;

[0012] The feeding tank is provided with a discharge pipe; the mixing area is connected with the adsorption column through the discharge pipe.

[0013] Preferably, an installation area is provided in the feeding tank, and the installation area is provided below the mixing area; a filter is provided between the installation area and the mixing area; a rotating fan is provided in the installation area; the rotating fan drives the nitrogen and silicon tetrachloride in the mixing area to rotate.

[0014] Preferably, a gearbox and a motor are arranged in the installation area; the motor is drivingly connected to the input shaft of the gearbox; and the output shaft of the gearbox is drivingly connected to the rotating fan.

[0015] Preferably, the top of the feeding tank is arranged as a circular arc top cover, and the discharge pipe is arranged on the top of the circular arc top cover.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] The utility model discloses a pressure pump that conveys silicon tetrachloride in the silicon tetrachloride raw material tank into a feeding tank; the feeding tank is externally connected to a nitrogen tank through a pipeline, and the nitrogen tank conveys nitrogen to the feeding tank; the feeding tank mixes the nitrogen and silicon tetrachloride and conveys them to an adsorption column; the adsorption column is provided with a tail gas discharge port, and the tail gas discharge port is connected to a tail gas treatment device through a pipeline; the nitrogen and silicon tetrachloride are mixed to achieve dilution of the silicon tetrachloride, and the content of silicon tetrachloride entering the adsorption column is controlled by automatic intermittent feeding with nitrogen blowing, so as to achieve control of the temperature of the adsorption column and greatly reduce the danger.

[0018] The present invention controls the content of silicon tetrachloride entering the adsorption column through automatic intermittent feeding with nitrogen-assisted blowing, controls the temperature in the gel activation process, and can effectively avoid the gel itself from losing activity due to loss of control due to excessively high temperature. After the gel is fully activated and put into use, the adsorption capacity of the boron element in the raw material trichlorosilane is enhanced, the boron content of trichlorosilane is reduced, and the product quality is improved, thereby effectively reducing the boron content in the downstream final silicon material product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a structural diagram of an adsorption system for removing boron from trichlorosilane provided in this embodiment;

[0020] Figure 2 It is a structural diagram of the feeding tank provided in this embodiment;

[0021] Figure 3 is a structural diagram of the jet assembly provided in this embodiment;

[0022] In the figure, 1 is a silicon tetrachloride raw material tank, 2 is a feed tank, 21 is an installation area, 22 is a mixing area, 23 is a spray pipe, 24 is a first feed pipe, 25 is a discharge pipe, 26 is an arc top cover, 27 is an atomizing nozzle, 28 is a pressure sensor, 29 is a gas nozzle, 210 is an injection assembly, 2101 is an injection main pipe, 2102 is an injection branch pipe, 211 is a second feed pipe, 212 is a motor, 213 is a gearbox, 214 is a rotating fan, 215 is a filter screen, 216 is a fixed frame, 217 is a bent pipe, 3 is an adsorption column, 4 is an exhaust gas treatment device, 5 is a pressure pump, 6 is a first solenoid valve, 7 is a second solenoid valve, 8 is a third solenoid valve, 9 is a temperature sensor, 10 is a pressure gauge, and 11 is a fourth solenoid valve. DETAILED DESCRIPTION

[0023] The utility model is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and cannot be used to limit the protection scope of the utility model.

[0024] It should be noted that in the description of the present invention, the directions or positional relationships indicated by the terms "front", "rear", "left", "right", "up", "down", "inside", "outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. The terms "front", "rear", "left", "right", "up", and "down" used in the description of the present invention refer to the directions in the accompanying drawings, and the terms "inside" and "outside" refer to the directions toward or away from the geometric center of a specific component, respectively.

[0025] like Figures 1 to 3 As shown, an adsorption system for removing boron from trichlorosilane includes a silicon tetrachloride raw material tank 1, a feed tank 2 and an adsorption column 3; the silicon tetrachloride raw material tank 1, the feed tank 2 and the adsorption column 3 are connected in sequence through pipelines.

[0026] The feeding tank 2 is provided with a mixing area 22 and an installation area 21 ; a spraying pipe 23 is provided on the top of the mixing area 22 ; the spraying pipe 23 is connected to the silicon tetrachloride raw material tank 1 through a first feeding pipe 24 ; and a plurality of atomizing nozzles 27 are provided on the spraying pipe 23 .

[0027] A jet assembly 210 is provided at the bottom of the mixing area 22, and the jet assembly 210 includes a jet main pipe 2101; a bent pipe 217 is provided on the jet main pipe 2101; the bent pipe 217 is connected to the nitrogen tank through a second feeding pipe 211; a plurality of jet branch pipes 2102 are connected to the jet main pipe 2101; the jet main pipe 2101 and the jet branch pipe 2102 are installed in the feeding tank 2 through a fixing frame 216; a plurality of gas nozzles 29 are evenly distributed on the jet main pipe 2101 and the jet branch pipe 2102, the atomizing nozzle 27 sprays silicon tetrachloride downward, and the plurality of gas nozzles 29 spray nitrogen upward, so that the nitrogen and silicon tetrachloride are fully mixed.

[0028] The top of the feeding tank 2 is provided with a circular arc top cover 26 , and the discharge pipe 25 is provided on the top of the circular arc top cover 26 ; the mixing area 22 is connected with the adsorption column 3 through the discharge pipe 26 .

[0029] The installation area 21 is arranged below the mixing area 22; a filter 215 is arranged between the installation area 21 and the mixing area 22; a rotating fan 214, a gearbox 213 and a motor 212 are arranged in the installation area 21; the motor 212 is drivingly connected to the input shaft of the gearbox 213; the output shaft of the gearbox 213 is drivingly connected to the rotating fan 214.

[0030] A pressure pump 5 is provided on the pipeline between the silicon tetrachloride raw material tank 1 and the feeding tank 2, and the pressure pump 5 transports the silicon tetrachloride in the silicon tetrachloride raw material tank 1 into the feeding tank 2; the feeding tank 2 is externally connected to a nitrogen tank through a pipeline, and the nitrogen tank transports nitrogen to the feeding tank; the rotating fan 214 drives the nitrogen and silicon tetrachloride in the mixing area 22 to rotate; when discharging is required, the rotating fan 214 blows the nitrogen and silicon tetrachloride mixture upward, and at the same time uses the arc top cover 26 to collect the nitrogen and silicon tetrachloride mixture into the discharge pipe 25.

[0031] A first solenoid valve 6 is arranged on the pipeline between the silicon tetrachloride raw material tank 1 and the feeding tank 2; a second solenoid valve 7 is arranged on the pipeline between the nitrogen tank and the feeding tank 2; a third solenoid valve 8 is arranged on the pipeline between the feeding tank 2 and the adsorption column 3; the first solenoid valve 6, the second solenoid valve 7, the third solenoid valve 8 and the pressure pump 5 are electrically connected to the controller; a pressure sensor 28 is arranged in the mixing area of ​​the feeding tank 2; a plurality of temperature sensors 9 are evenly arranged on the side wall of the adsorption column 3 in the vertical direction; the pressure sensor 28 and the temperature sensor 9 are electrically connected to the controller.

[0032] The feeding tank 2 mixes the nitrogen and silicon tetrachloride and transports them to the adsorption column 3; the adsorption column 3 is provided with a tail gas discharge port, and the tail gas discharge port is connected to the tail gas treatment device 4 through a pipeline; a fourth solenoid valve 11 and a pressure gauge 10 are provided on the pipeline between the tail gas discharge port and the tail gas treatment device 4; the fourth solenoid valve 11 and the pressure gauge 10 are electrically connected to the controller.

[0033] Working process: when the adsorption column needs to activate the gel, the controller controls the first solenoid valve to open, and controls the pressure pump 5 to transport the silicon tetrachloride in the silicon tetrachloride raw material tank 1 into the feeding tank 2; the controller controls the second solenoid valve to open, and the nitrogen tank transports nitrogen to the feeding tank 2;

[0034] The controller controls the motor 212 to drive the rotating fan 214 to rotate, and the rotating fan 214 drives the nitrogen and silicon tetrachloride in the mixing area 22 to fully mix and rotate, so as to avoid excessively rapid local heating of the adsorption column 3 due to uneven silicon tetrachloride concentration in the mixture fed into the adsorption column.

[0035] When the pressure detected by the pressure sensor 28 in the feeding tank 2 is greater than the set threshold value A, the controller controls the first solenoid valve 6 to close; the controller controls the third solenoid valve 8 and the second solenoid valve 7 to open, and the fan 214 is rotated to blow the nitrogen and silicon tetrachloride mixture upward, and the arc top cover 26 is used to collect the nitrogen and silicon tetrachloride mixture to the discharge pipe 25, and the nitrogen and silicon tetrachloride mixture is sent to the adsorption column 3 through the discharge pipe 25;

[0036] When the temperature sensor 9 detects that the temperature of the adsorption column rises by 5°C / min, the controller controls the third solenoid valve 8 and the second solenoid valve 7 to close; when the temperature sensor 9 detects that the temperature of the adsorption column rises by less than 2°C / min, the controller controls the third solenoid valve 8 and the second solenoid valve 7 to open.

[0037] When the pressure detected by the pressure sensor 28 in the feeding tank 2 is less than the set threshold value B, the controller controls the first solenoid valve 6 to open, and controls the pressure pump 5 to continue to transport the silicon tetrachloride in the silicon tetrachloride raw material tank 1 into the feeding tank 2 .

[0038] In this embodiment, nitrogen and silicon tetrachloride are mixed to dilute the silicon tetrachloride, and the silicon tetrachloride content entering the adsorption column is controlled by automatic intermittent feeding with nitrogen blowing, so that the temperature of the adsorption column is controlled, which greatly reduces the danger.

[0039] At the same time, by controlling the temperature during the gel activation process, it is possible to effectively avoid the gel itself from losing activity due to loss of control over excessively high temperatures. After the gel is fully activated and put into use, it can enhance its adsorption capacity for the boron element in the raw material trichlorosilane, reduce the boron content of trichlorosilane, and improve product quality, thereby effectively reducing the boron content in the downstream final silicon material product.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An adsorption system for removing boron from trichlorosilane, characterized in that: It comprises a silicon tetrachloride raw material tank, a feeding tank and an adsorption column; the silicon tetrachloride raw material tank, the feeding tank and the adsorption column are connected in sequence through a pipeline; a pressure pump is arranged on the pipeline between the silicon tetrachloride raw material tank and the feeding tank, and the pressure pump transports the silicon tetrachloride in the silicon tetrachloride raw material tank into the feeding tank; The feeding tank is connected to a nitrogen tank through a pipeline, and the nitrogen tank transports nitrogen to the feeding tank; the feeding tank mixes the nitrogen and silicon tetrachloride and transports them to the adsorption column; the adsorption column is provided with a tail gas discharge port, and the tail gas discharge port is connected to the tail gas treatment device through a pipeline.

2. The adsorption system for removing boron from trichlorosilane according to claim 1, characterized in that: A first solenoid valve is arranged on the pipeline between the silicon tetrachloride raw material tank and the feeding tank; a second solenoid valve is arranged on the pipeline between the nitrogen tank and the feeding tank; a third solenoid valve is arranged on the pipeline between the feeding tank and the adsorption column; the first solenoid valve, the second solenoid valve, the third solenoid valve and the pressure pump are electrically connected to the controller.

3. The adsorption system for removing boron from trichlorosilane according to claim 2, characterized in that: A pressure sensor is arranged in the feeding tank; a plurality of temperature sensors are evenly arranged on the side wall of the adsorption column along the vertical direction; and the pressure sensor and the temperature sensor are electrically connected to the controller.

4. The adsorption system for removing boron from trichlorosilane according to claim 2, characterized in that: A fourth solenoid valve and a pressure gauge are provided on the pipeline between the exhaust gas discharge port and the exhaust gas treatment device; the fourth solenoid valve and the pressure gauge are electrically connected to the controller.

5. The adsorption system for removing boron from trichlorosilane according to claim 1, characterized in that: The feed tank is provided with a mixing area; a spray pipe is provided on the top of the mixing area; the spray pipe is connected to the silicon tetrachloride raw material tank through a first feed pipe; a plurality of atomizing nozzles are provided on the spray pipe; the atomizing nozzles spray silicon tetrachloride downwards; The bottom of the mixing area is provided with a jet assembly, and the jet assembly includes a jet main pipe; the jet main pipe is connected to the nitrogen tank through a second feed pipe; the jet main pipe is connected to a plurality of jet branch pipes; a plurality of gas nozzles are evenly distributed on the jet main pipe and the jet branch pipes, and the plurality of gas nozzles spray nitrogen upwards; The feeding tank is provided with a discharge pipe; the mixing area is connected with the adsorption column through the discharge pipe.

6. The adsorption system for removing boron from trichlorosilane according to claim 5, characterized in that: An installation area is provided in the feeding tank, and the installation area is provided below the mixing area; a filter screen is provided between the installation area and the mixing area; a rotating fan is provided in the installation area; the rotating fan drives the nitrogen and silicon tetrachloride in the mixing area to rotate.

7. The adsorption system for removing boron from trichlorosilane according to claim 6, characterized in that: A gearbox and a motor are arranged in the installation area; the motor is drivingly connected to the input shaft of the gearbox; and the output shaft of the gearbox is drivingly connected to the rotating fan.

8. The adsorption system for removing boron from trichlorosilane according to claim 6, characterized in that: The top of the feeding tank is arranged as a circular arc top cover, and the discharge pipe is arranged on the top of the circular arc top cover.

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