A system for preparing boron trichloride by reacting boron carbide with chlorine

Abstract

The application relates to the field of special gas production, and discloses a system for preparing boron trichloride by reacting boron carbide with chlorine, which comprises the following devices connected by pipelines: a gas source device for providing chlorine; a reaction device connected with the gas source device, wherein the chlorine in the gas source device can enter the reaction device, and the reaction device is used for loading boron carbide; a condensing device connected with a discharge port of the reaction device and used for condensing boron trichloride; a material receiving device connected with a discharge port of the condensing device to receive the condensed boron trichloride; and a tail gas treatment device connected with the reaction device and the condensing device. The application can sufficiently dry the boron carbide, and has a good treatment effect on the chlorine in the tail gas.

Description

Technical Field

[0001] This application relates to the technical field of specialty industrial gases, and in particular to a system for preparing boron trichloride by reacting boron carbide with chlorine. Background Technology

[0002] Currently, boron trichloride is used in processes such as diffusion, ion implantation, dry etching, and the manufacture of solar cell elements in silicon semiconductor devices. With the gradual depletion of global energy resources such as oil, increasing environmental pollution, and the climate impact of the greenhouse effect, countries worldwide are vigorously developing clean energy and energy-saving technologies. Against this backdrop, my country's solar cell, semiconductor light-emitting device, and related industries have experienced rapid development, leading to a growing demand for boron trichloride. In semiconductor applications, electronic-grade boron trichloride is typically required; therefore, industrial-grade boron trichloride must first be prepared and then purified to obtain electronic-grade boron trichloride.

[0003] In some related technologies, boric acid is loaded onto activated carbon and then reacted with chlorine gas. However, if moisture is present in the reaction system, the product boron trichloride is prone to hydrolysis, which can reduce the production efficiency of boron trichloride. Therefore, high-temperature chlorine gas is generally used in the production process to remove moisture from the boric acid and activated carbon. However, boric acid can react with chlorine gas at around 300℃, so the chlorine temperature usually needs to be below 280℃. But at this temperature, the moisture in the activated carbon cannot be removed effectively, and the boron trichloride product will still react with the present moisture to produce byproducts. Therefore, the production of boron trichloride still needs continuous optimization. Summary of the Invention

[0004] To improve the production purity of boron trichloride, this application provides a system for preparing boron trichloride by reacting boron carbide with chlorine.

[0005] This application provides a system for preparing boron trichloride by reacting boron carbide with chlorine gas, which adopts the following technical solution:

[0006] A system for preparing boron trichloride by reacting boron carbide with chlorine gas includes:

[0007] Gas supply device, used to provide chlorine gas;

[0008] The reaction apparatus is connected to the gas source device, wherein chlorine gas from the gas source device can enter the reaction apparatus and the reaction apparatus is used to fill boron carbide.

[0009] A condenser is connected to the outlet of the reaction device and is used to condense boron trichloride;

[0010] A receiving device is connected to the outlet of the condensing device to receive condensed boron trichloride;

[0011] The device includes a tail gas treatment unit. The reaction unit and the condensation unit are both connected to the tail gas treatment unit. The tail gas treatment unit includes a tower body and a spray unit connected to the tower body. The upper end of the tower body is provided with a gas outlet. The spray unit is used to spray a treatment liquid that can neutralize chlorine gas into the tower body from the upper end of the tower body. The upper end of the tower body is provided with a packing layer. The treatment liquid is sprayed above the packing layer.

[0012] By adopting the above technical solution, boron trichloride is prepared by reacting chlorine and boron carbide in this application. The initial reaction temperature of chlorine and boron carbide is about 400°C. Therefore, boron carbide can be dried by blowing chlorine at a temperature below 400°C. The drying effect is good and there is no loss of raw materials. The blown-off chlorine enters the tail gas treatment device to neutralize the chlorine. Other gases that do not participate in the reaction are discharged from the top of the tower.

[0013] Optionally, when chlorine is used to purge air from the pipeline and dry boron carbide, the temperature of the reaction apparatus is controlled between 300-350°C.

[0014] By adopting the above technical solution, the drying effect of boron carbide is good, and most of the moisture can be removed.

[0015] Optionally, the temperature of the reaction apparatus is controlled between 650-800°C during the reaction.

[0016] Optionally, the spraying component includes a spray pipe and a power pump mounted on the spray pipe. The lower end of the spray pipe is connected to the side wall of the tower body, and the upper end of the spray pipe is connected to the upper side wall of the tower body.

[0017] By adopting the above technical solution, the spray pipe can continuously spray the treatment liquid into the tower, so that the treatment liquid can come into contact with chlorine gas for neutralization. Furthermore, the packing layer is located below the spray nozzle, and the gaps in the packing will contain the treatment liquid. When chlorine gas passes through the gaps in the packing, it can also be neutralized, thereby improving the neutralization effect of chlorine gas. In addition, a large amount of treatment liquid can be filled into the tower, and the treatment liquid in the tower can be extracted and recycled by a power pump.

[0018] Optionally, the packing layer includes a first material layer and a second material layer arranged from bottom to top in the tower body. The first material layer and the lower part of the tower body form a first space. Chlorine gas enters the tower body from the side wall of the first space. A second space is formed between the first material layer and the second material layer. The upper outlet of the spray pipe is located above the second material layer.

[0019] By adopting the above technical solution, the first material layer divides the tower body into a first space and a second space. Chlorine is neutralized in the first space, and part of it passes through the first material layer into the second space for neutralization. Then it passes through the second material layer, which is beneficial to the neutralization of chlorine.

[0020] Optionally, the first material layer includes an installation frame, which is a hollow structure filled with filler. The installation frame is rotatably connected to the inner wall of the tower body, and a drive source for driving the installation frame to rotate is installed on the side wall of the tower body. An opening is provided on the installation frame, and a branch pipe is provided on the spray pipe. The branch pipe passes through the second material layer and extends from the opening into the first space. A nozzle is provided at one end of the branch pipe in the first space. A cover plate is slidably provided on the side wall of the branch pipe. The cover plate and the installation frame are linked. When the installation frame rotates, the cover plate can switch between disengaging from the installation frame and abutting against the surface of the installation frame.

[0021] By adopting the above technical solution, the mounting frame is rotatably installed on the inner wall of the tower body. When the mounting frame rotates, the cover plate can close or open the opening. That is, chlorine gas first enters the first space, and the treatment liquid dripping from the first material layer and the treatment liquid sprayed from the nozzle treat the chlorine gas. When the cover plate is opened, the first space and the second space are connected, and chlorine gas can suddenly enter the second space, thereby depressurizing the first space and reducing the situation of high pressure caused by low chlorine treatment efficiency in the first space, ensuring that chlorine gas enters the first space normally.

[0022] Optionally, the cover plate has an internal hollow structure, and an annular protrusion is provided on the upper surface of the cover plate. The annular protrusion abuts against the side wall of the branch pipe, and a water distribution port is provided on the side wall of the branch pipe. When the cover plate abuts against the surface of the mounting frame, the annular protrusion covers the water distribution port. When the cover plate slides upward, the water distribution port can communicate with the inner cavity of the cover plate. An arc-shaped groove is provided on the bottom surface of the cover plate, and the arc-shaped groove is evenly distributed along the circumference of the cover plate.

[0023] By adopting the above technical solution, when the cover moves upward, the treatment liquid can flow into the inner cavity of the cover through the water distribution port and flow downward from the arc groove, thereby forming a water curtain. This allows the chlorine gas to better contact and react with the treatment liquid when it passes through the opening, while some of it enters the second space through the gap between the water curtains.

[0024] Optionally, the lower surface of the cover plate is provided with an extension rod extending downward into the opening, and the side wall of the extension rod is provided with a positioning rod. The inner wall of the opening is provided with an annular groove, and the end of the positioning rod extends into the annular groove. The inner wall of the annular groove has an upper slope section and a lower slope section. When the positioning rod moves in the upper slope section, the cover plate can move upward. When the positioning rod moves in the lower slope section, the cover plate can move downward and abut against the upper surface of the mounting frame.

[0025] By adopting the above technical solution, the positioning rod can move in the annular groove when the mounting frame rotates, and can drive the cover plate to move upward when on the uphill section.

[0026] Optionally, a sleeve is provided on the inner wall of the mounting frame. The sleeve is arranged radially along the mounting frame, with one end extending to the outer wall of the mounting frame and the other end extending to the inner wall of the opening. A sliding rod is slidably arranged inside the sleeve, and an abutment block is provided on the side wall of the sliding rod. A slot is provided on the outer wall of the sleeve for the abutment block to slide. A trigger block is provided on the side wall of the branch pipe. When the mounting frame rotates, the sliding rod at the opening end can be pressed by the trigger block and slide away from the branch pipe. There is a gap between the outer wall of the mounting frame and the inner wall of the tower body, and a protrusion is provided on the inner wall of the tower body. When the mounting frame rotates, one end of the sliding rod can be pressed by the protrusion and slide closer to the branch pipe.

[0027] By adopting the above technical solution, when the mounting frame rotates, one end of the sliding rod abuts against the protrusion or trigger block, so that the sliding rod can slide back and forth in the sleeve, driving the abutting block to slide in the slot. The abutting block can then drive the packing to move, causing the treatment liquid in the packing gap to flow downward.

[0028] Optionally, both ends of the sliding rod are arc-shaped structures.

[0029] In summary, this application includes at least one of the following beneficial effects:

[0030] 1. Boron trichloride is prepared by reacting boron carbide with chlorine. The boron carbide can be dried by controlling the temperature and the flow rate of chlorine, resulting in good drying effect. The prepared boron trichloride is condensed in a condenser and then loaded into the receiving device. The chlorine tail gas is treated by a tail gas treatment device. Attached Figure Description

[0031] Figure 1 This is a process flow diagram of an embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the exhaust gas treatment device in the embodiments of this application;

[0033] Figure 3This is a three-dimensional structural schematic diagram of the exhaust gas treatment device in the embodiments of this application;

[0034] Figure 4 This is a schematic diagram of the internal structure of the tower body in an embodiment of this application;

[0035] Figure 5 This is a schematic diagram of the mounting frame structure in an embodiment of this application;

[0036] Figure 6 This is an exploded view of the cover plate in an embodiment of this application;

[0037] Figure 7 This is a cross-sectional schematic diagram of the mounting frame in an embodiment of this application;

[0038] Figure 8 This is a structural diagram illustrating the protrusion;

[0039] Figure 9 This is a schematic diagram of the sleeve structure.

[0040] Explanation of reference numerals in the attached drawings: 1. Gas source device; 2. Reaction device; 3. Condensation device; 4. Feeding device; 5. Tail gas treatment device; 51. Tower body; 52. Spray component; 521. Spray pipe; 522. Circulating pump; 6. Gas outlet; 7. Packing layer; 8. First material layer; 81. Mounting frame; 82. Opening; 9. Second material layer; 10. First space; 11. Second space; 12. Drive source; 121. Gear 122. Wheel; 123. Motor; 124. Tooth; 13. Branch pipe; 14. Nozzle; 15. Cover plate; 16. Ring protrusion; 17. Water outlet; 18. Arc groove; 19. Extension rod; 20. Positioning rod; 21. Ring groove; 22. Uphill section; 23. Downhill section; 24. Sleeve; 25. Sliding rod; 26. Contact block; 27. Slot; 28. Trigger block; 29. ​​Protrusion; 30. Limiting ring; 31. Guide groove. Detailed Implementation

[0041] The following is in conjunction with the appendix Figure 1-9 This application will be described in further detail.

[0042] This application discloses a system for preparing boron trichloride by reacting boron carbide with chlorine gas. (Refer to...) Figure 1The system comprises a gas source device 1, a reaction device 2, a condenser device 3, a receiving device 4, and a tail gas treatment device 5, all connected sequentially via pipelines. The gas source device 1 can use a 40-liter 16-cylinder chlorine cylinder container as raw material and a nitrogen-containing cylinder container. The gas source device 1 is connected to the gas supply pipeline to provide chlorine and nitrogen. The gas source device 1 is connected to the reaction device 2, which is a reactor made of quartz glass tube and heated by a far-infrared electric heater. Boron carbide is added to the reactor, and the reactor's heating temperature is set between 300-350℃. First, nitrogen is used to purge air and moisture from the pipeline. When the moisture content is below a specified value, the reactor temperature is then raised to 650℃, and chlorine is introduced. The chlorine reacts exothermically with boron carbide in the reactor at a reaction temperature of 650-800℃. In this application, two sets of reaction devices 2 are installed in parallel in the pipeline connection. Since the boron carbide will be consumed after the reaction time, when one reactor is working, the other reactor performs pretreatment work such as boron carbide replacement and impurity discharge, thereby saving downtime and improving production efficiency.

[0043] Chlorine gas enters the reactor from the top, and the produced boron trichloride exits from the bottom. A radiator and a filter valve are connected to the outlet pipe of the reactor. The boron trichloride passes through the radiator and filter valve before entering the condenser unit 3 for condensation. The pipe passing through the radiator and filter valve is also connected to the tail gas treatment device. Initially, when the purity of the synthesis gas is insufficient, it is first discharged to the tail gas treatment device; once the purity meets the standard, it is sent to the condenser unit 3. The condenser unit 3 in this application uses a shell-and-tube condenser made of Ф108×4 stainless steel tubing. The cold source of the condenser consists of an ethylene glycol cold source tank, dry carbon dioxide ice, and a circulating pump. The cold source temperature is -15℃. During use, dry carbon dioxide ice is added as needed based on the temperature rise. The refrigerant is sent to the boron trichloride condenser by the circulating pump 522, and after heat exchange, it returns to the refrigerant storage tank for repeated use.

[0044] Boron trichloride gas from reaction device 2 enters the condenser through the condenser inlet. After condensation and liquefaction, the gas enters the receiving device 4 through the condenser outlet. In this application, the receiving device 4 is a steel cylinder, which needs to be insulated, such as by wrapping an insulation layer around its outer wall. The steel cylinder is placed on an electronic scale to easily monitor the amount of boron trichloride in it.

[0045] Reference Figure 2The gas exiting the reactor includes condensable boron trichloride gas and non-condensable chlorine gas. The outlet 6 of the condenser is connected to the tail gas treatment device 5, and the tail gas exiting the condenser is treated by the tail gas treatment device 5. Both the reaction device 2 and the condenser 3 are connected to the tail gas treatment device 5, and the chlorine gas in the reaction device 2 and the condenser 3 can be directly discharged into the tail gas treatment device 5. At the beginning of the reaction, the purity of the boron trichloride product is not yet sufficient, so the gas exiting the reactor does not enter the condenser temporarily but is first discharged into the tail gas treatment device 5. When the purity of the boron trichloride exiting the reactor meets the standard, the synthesis gas is then sent to the condenser.

[0046] Reference Figure 3 and Figure 4 The exhaust gas treatment device 5 includes a tower body 51 and a spray unit 52 installed on the tower body 51. An exhaust port 6 is provided at the upper end of the tower body 51. The reaction device 2 and the condensation device 3 are both connected to the side wall of the tower body 51 via gas supply pipes, allowing the exhaust gases from the reaction device 2 and the condensation device 3 to enter the tower body 51. The main exhaust gas treated in this application is chlorine gas. The spray unit 52 is used to spray a treatment liquid capable of neutralizing the chlorine gas phase into the tower body 51; sodium hydroxide solution is selected as the appropriate choice. There is also a certain amount of sodium hydroxide solution inside the tower body 51. The spraying component 52 includes a spray pipe 521 and a circulation pump 522 installed on the spray pipe 521. The lower end of the spray pipe 521 is connected to the lower side wall of the tower body 51, and the upper end of the spray pipe 521 is connected to the upper end of the tower body 51. The circulation pump 522 extracts sodium hydroxide from the tower body 51 and sprays it into the tower from the upper end of the tower body 51, thereby improving the neutralization effect of chlorine and sodium hydroxide.

[0047] Reference Figure 4 To improve the treatment effect of chlorine gas, a packing layer 7 is also provided on the inner wall of the upper end of the tower body 51. The upper end of the spray pipe 521 is located above the packing layer 7, that is, the water sprayed from the spray pipe 521 can fall on the packing, and then flow downward and drip through the gaps between the packing. The packing can be granular materials such as zeolite. When the gas enters the tower body 51, the chlorine gas can react with sodium hydroxide. Some of the gas moves upward through the gaps between the packing. The chlorine gas can react with the treatment liquid in the gaps between the packing. The sodium chloride and sodium hypochlorite produced by the reaction fall to the bottom of the tower with the treatment liquid. The unreacted gas moves upward and is discharged from the gas outlet 6 of the tower body 51.

[0048] Reference Figure 4The packing layer 7 includes a first material layer 8 and a second material layer 9, with the first material layer 8 located below the second material layer 9. A first space 10 is formed between the first material layer 8 and the tower body 51, and a second space 11 is formed between the first material layer 8 and the second material layer 9. The upper outlet of the spray pipe 521 is located above the second material layer 9. The treatment liquid can drip down from the second material layer 9 and from the first material layer 8, thus neutralizing chlorine gas in both the first space 10 and the second space 11. Furthermore, the chlorine gas can be neutralized in the gaps between the packing layers as it passes between the first material layer 8 and the second material layer 9, thereby improving the neutralization effect.

[0049] Reference Figure 5 and Figure 6 The first material layer 8 includes a mounting frame 81, which has a hollow internal structure and porous upper and lower surfaces. The packing material fills the mounting frame 81, allowing the treatment liquid to flow out. The upper end of the tower body 51 has a circular structure. The mounting frame 81 and the tower body 51 are coaxially arranged, and the mounting frame 81 is rotatably mounted on the inner wall of the tower body 51. A drive source 12 for driving the mounting frame 81 to rotate is installed on the side wall of the tower body 51. An opening 82 is provided at the center of the mounting frame 81. A branch pipe 13 is connected to the upper end of the spray pipe 521. The branch pipe 13 passes through the second material layer 9 and through the opening 82, extending into the first space 10. A nozzle 14, preferably an atomizing nozzle, is installed at the lower end of the branch pipe 13. When the upper end of the spray pipe 521 sprays the treatment liquid, the nozzle 14 also sprays the treatment liquid, thereby improving the treatment efficiency of chlorine gas in the first space 10.

[0050] Reference Figure 4 and Figure 6 A cover plate 15 is slidably installed vertically on the outer wall of branch pipe 13. The cover plate 15 and the mounting frame 81 are linked. When the mounting frame 81 rotates, it can drive the cover plate 15 to slide upward. After sliding upward, the cover plate 15 can disengage from the upper surface of the mounting frame 81. When the cover plate 15 slides downward, it can abut against the upper surface of the mounting frame 81 to close the opening 82. After the cover plate 15 moves upward, the first space 10 and the second space 11 are connected instantly. The pressure in the first space 10 can be reduced, allowing chlorine gas to enter the first space 10 normally.

[0051] Reference Figure 6 and Figure 7The cover plate 15 has a hollow internal structure. An annular protrusion 16 is coaxially fixed to the upper surface of the cover plate 15, and the annular protrusion 16 abuts against the outer wall of the branch pipe 13. A water distribution port 17 is provided on the outer wall of the branch pipe 13. When the cover plate 15 abuts against the upper surface of the mounting frame 81, the annular protrusion 16 can cover the water distribution port 17. When the cover plate 15 slides up and down, the water distribution port 17 can coincide with the inner cavity of the cover plate 15, allowing the treatment fluid in the branch pipe 13 to enter the inner cavity of the cover plate 15. An arc-shaped groove 18 is provided on the inner bottom surface of the cover plate 15, and three arc-shaped grooves 18 are evenly arranged along the circumference of the cover plate 15. After the cover plate 15 slides upward, the treatment liquid inside the cover plate 15 can flow downward from the arc-shaped groove 18, thereby forming a water curtain. When the chlorine gas in the first space 10 enters the second space 11 through the opening 82, it can come into contact with the water curtain and finally enter the second space 11 through the gap between the water curtains, thereby neutralizing most of the chlorine gas when passing through the water curtain. In order to make the cover plate 15 slide up and down without rotating circumferentially, the side wall of the branch pipe 13 is provided with a guide groove 31, and the inner wall of the annular protrusion 16 is fixed with a guide block (not shown in the figure) that can slide in the guide groove 31.

[0052] Reference Figure 4 and Figure 5 Two limiting rings 30 are installed on the inner wall of the tower body 51 using screws or other means. The mounting frame 81 is rotatably mounted between the two limiting rings 30. To improve the stability of the mounting frame 81, the limiting rings 30 can have stepped edges, and the mounting frame 81 abuts against the stepped edges. The upper surface of the mounting frame 81 is uniformly fixed with teeth 123 along the circumference of the mounting frame 81. The drive source 12 includes a gear 121 rotatably mounted on the side wall of the tower body 51, and a motor 122 for driving the gear 121 to rotate. The gear 121 can mesh with the teeth 123, thereby driving the mounting frame 81 to rotate. The upper surface of the mounting frame 81 can be detachably connected to a sealing plate by screws, which facilitates the replacement of the packing in the later stage. The second material layer 9 is formed by fixing a porous filter plate on the inner wall of the tower body 51, and the packing is placed directly on the filter plate.

[0053] Reference Figure 6 and Figure 7 An extension rod 19 extending downward into the opening 82 is fixed to the lower surface of the cover plate 15, and a positioning rod 20 is fixed to the side wall of the extension rod 19. An annular groove 21 is formed on the inner wall of the opening 82, and the end of the positioning rod 20 away from the extension rod 19 extends into the annular groove 21. The inner wall of the annular groove 21 has an upper slope section 22 and a lower slope section 23. When the mounting frame 81 rotates, the positioning rod 20 can move relative to the opening 82, and can first move upward on the upper slope section 22, thereby driving the cover plate 15 to move upward. When it moves to the lower slope section 23 and opens the lower slope, the cover plate 15 moves downward, thereby causing the cover plate 15 to close again in the opening 82, thus realizing the reciprocating up and down movement of the cover plate 15 when the mounting frame 81 rotates.

[0054] Reference Figure 7 and Figure 8 Furthermore, a sleeve 24 is fixed to the inner wall of the mounting frame 81. The sleeve 24 extends radially along the mounting frame 81, with one end opening 82 penetrating to the side wall of the mounting frame 81 and the other end penetrating to the inner wall of the opening 82. A sliding rod 25 is slidably disposed inside the sleeve 24, with both ends of the sliding rod 25 having an arc-shaped structure. When the mounting frame 81 is installed on the inner wall of the tower body 51, there is a certain gap between the outer wall of the mounting frame 81 and the inner wall of the tower body 51. Figure 9 Protrusions 29 are fixed at intervals along the circumference of the inner wall of the tower body 51, and trigger blocks 28 are symmetrically fixed on the side wall of the branch pipe 13. When the mounting frame 81 rotates, one end of the sliding rod 25 abuts against the protrusion 29, thereby causing the sliding rod 25 to slide towards the branch pipe 13, and the end of the sliding rod 25 can extend into the opening 82. As the mounting frame 81 continues to rotate, the sliding rod 25 and the protrusion 29 disengage, the end of the sliding rod 25 abuts against the trigger block 28, and the sliding rod 25 slides back into the sleeve 24, so that the sliding rod 25 can slide back and forth in the sleeve 24 when the mounting frame 81 rotates. The sliding rod 25 has abutment blocks 26 fixed at intervals on its side wall. The outer wall of the sleeve 24 has a slot 27 for sliding the abutment blocks 26. The abutment blocks 26 extend beyond the surface of the sleeve 24. When the sliding rod 25 slides, it can push the packing to shake through the abutment blocks 26, which helps the flow of the treatment liquid in the packing.

[0055] The implementation principle of the system for preparing boron trichloride by reacting boron carbide with chlorine in this application embodiment is as follows: First, the air in the pipeline and reactor is purged with nitrogen at a pressure of 0.2 MPa. Then, the infrared electric heater is started to adjust the reactor temperature to 300-350°C. Nitrogen is then used to remove moisture from the boron carbide until the moisture level is below a predetermined value. The nitrogen inlet is then shut off, and the infrared electric heater temperature is set to 650°C. After the reactor temperature reaches 650°C, chlorine is supplied, allowing the chlorine and boron carbide to undergo an exothermic reaction in the reactor at a temperature of 650-800°C. The initial synthesis gas (boron trichloride) is first introduced into the tail gas treatment device 5. Once the purity of the synthesis gas reaches a predetermined value, it can be introduced into the condenser for condensation and liquefaction. The liquefied boron trichloride is then sent to the receiving device 4, while the non-condensable gas exits the condenser and enters the tail gas treatment device 5 for chlorine removal.

[0056] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A system for preparing boron trichloride by reacting boron carbide with chlorine gas, characterized in that: Including those connected by pipes: Gas source device (1) is used to supply chlorine gas; The reaction device (2) is connected to the gas source device (1), and the chlorine gas in the gas source device (1) can enter the reaction device (2) and the reaction device (2) is used to fill boron carbide. A condenser (3) is connected to the outlet of the reaction device (2) and is used to condense boron trichloride; The receiving device (4) is connected to the outlet of the condensing device (3) to receive the condensed boron trichloride; And a tail gas treatment device (5), the reaction device (2) and the condensation device (3) are connected to the tail gas treatment device (5). The tail gas treatment device (5) includes a tower body (51) and a spray element (52) connected to the tower body (51). The upper end of the tower body (51) is provided with an outlet (6). The spray element (52) is used to spray a treatment liquid that can neutralize chlorine into the tower body (51) from the upper end of the tower body (51). The upper end of the tower body (51) is provided with a packing layer (7). The position of the treatment liquid spraying is above the packing layer (7). The spraying component (52) includes a spray pipe (521) and a power pump installed on the spray pipe (521). The lower end of the spray pipe (521) is connected to the side wall of the tower body (51), and the upper end of the spray pipe (521) is connected to the upper side wall of the tower body (51). The packing layer (7) includes a first material layer (8) and a second material layer (9) arranged from bottom to top in the tower body (51). A first space (10) is formed below the first material layer (8) and the tower body (51). Chlorine gas enters the tower body (51) from the side wall of the first space (10). A second space (11) is formed between the first material layer (8) and the second material layer (9). The upper outlet of the spray pipe (521) is located above the second material layer (9). The first material layer (8) includes a mounting frame (81), which is a hollow structure. The packing filler is placed inside the mounting frame (81). The mounting frame (81) is rotatably connected to the inner wall of the tower body (51), and a drive source (12) for driving the mounting frame (81) to rotate is installed on the side wall of the tower body (51). An opening (82) is provided on the mounting frame (81), and a branch pipe (13) is provided on the spray pipe (521). The branch pipe (13) passes through... The second material layer (9) extends from the opening (82) into the first space (10). The branch pipe (13) is provided with a nozzle (14) at one end in the first space (10). The side wall of the branch pipe (13) is provided with a cover plate (15) that slides up and down. The cover plate (15) and the mounting frame (81) are linked together. When the mounting frame (81) rotates, the cover plate (15) can switch between disengaging from the mounting frame (81) and abutting against the surface of the mounting frame (81). The cover plate (15) has an internal hollow structure, and an annular protrusion (16) is provided on the upper surface of the cover plate (15). The annular protrusion (16) abuts against the side wall of the branch pipe (13). A water outlet (17) is provided on the side wall of the branch pipe (13). When the cover plate (15) abuts against the surface of the mounting frame (81), the annular protrusion (16) covers the water outlet (17). When the cover plate (15) slides upward, the water outlet (17) can communicate with the inner cavity of the cover plate (15). An arc groove (18) is provided on the bottom surface of the cover plate (15). The arc groove (18) is evenly arranged along the circumference of the cover plate (15). The lower surface of the cover plate (15) is provided with an extension rod (19) extending downward into the opening (82), and the side wall of the extension rod (19) is provided with a positioning rod (20). The inner wall of the opening (82) is provided with an annular groove (21), and the end of the positioning rod (20) extends into the annular groove (21). The inner wall of the annular groove (21) has an upslope section (22) and a downslope section (23). When the positioning rod (20) moves in the upslope section (22), the cover plate (15) can move upward. When the positioning rod (20) moves in the downslope section (23), the cover plate (15) can move downward and abut against the upper surface of the mounting frame (81).

2. The system for preparing boron trichloride by reacting boron carbide with chlorine gas according to claim 1, characterized in that: When chlorine is used to purge air from the pipeline and dry boron carbide, the temperature of the reaction device (2) is controlled between 300-350°C.

3. The system for preparing boron trichloride by reacting boron carbide with chlorine gas according to claim 1, characterized in that: During the reaction, the temperature of the reaction device (2) is controlled between 650-800℃.

4. The system for preparing boron trichloride by reacting boron carbide with chlorine gas according to claim 3, characterized in that: A sleeve (24) is provided on the inner wall of the mounting frame (81). The sleeve (24) is arranged along the radial direction of the mounting frame (81), and one end of the sleeve (24) extends through to the outer wall of the mounting frame (81), and the other end extends through to the inner wall of the opening (82). A sliding rod (25) is slidably arranged inside the sleeve (24). An abutment block (26) is provided on the side wall of the sliding rod (25). A slot (27) is opened on the outer wall of the sleeve (24) for the abutment block (26) to slide. The branch pipe (13) The side wall is provided with a trigger block (28). When the mounting frame (81) rotates, the sliding rod (25) at one end of the opening (82) can be pressed by the trigger block (28) and slide away from the branch pipe (13). There is a gap between the outer wall of the mounting frame (81) and the inner wall of the tower body (51), and a protrusion (29) is provided on the inner wall of the tower body (51). When the mounting frame (81) rotates, one end of the sliding rod (25) can be pressed by the protrusion (29) and slide towards the branch pipe (13).

5. The system for preparing boron trichloride by reacting boron carbide with chlorine gas according to claim 4, characterized in that: Both ends of the sliding rod (25) are arc-shaped structures.

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