System for treating amorphous silicon powder in electronic-grade polycrystalline silicon tail gas

Abstract

The utility model discloses a system for treating amorphous silicon powder in electronic-grade polycrystalline silicon tail gas, relates to the technical field of polycrystalline silicon production, and mainly aims to remove and reduce the amorphous silicon powder in the tail gas and reduce the failure rate of tail gas recovery unit equipment. According to the main technical scheme, the treatment system for the amorphous silicon powder in the electronic-grade polycrystalline silicon tail gas is characterized in that the upper end of a tower body is connected to an exhaust pipe, and the lower end of the tower body is connected to a filter; the separation part comprises a spraying mechanism and a cyclone separation mechanism, the spraying mechanism and the cyclone separation mechanism are sequentially arranged in the tower body from top to bottom, the spraying mechanism comprises a spraying structure and a filler structure which are sequentially arranged from top to bottom, a tangential inlet pipe of the cyclone separation mechanism penetrates through the side wall of the tower body, and a tangential outlet pipe of the cyclone separation mechanism penetrates through the side wall of the tower body. A cover body is arranged at an upper end outlet of the cyclone separation mechanism and is used for preventing spraying liquid from entering the cyclone separation mechanism through the upper end outlet.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon production, in particular to a system for processing amorphous silicon powder in electronic-grade polysilicon tail gas. Background Art

[0002] At present, electronic-grade polysilicon is mainly produced by the modified Siemens method. Due to factors such as the ratio of the reduction furnace, the different currents and temperatures at different stages, the recovered gaseous chlorosilane contains a large amount of amorphous silicon powder. SiHCl3 and hydrogen undergo chemical vapor deposition reaction in the reduction furnace to prepare polysilicon. The specific reaction equation is: 3SiHCl3+H2→2Si+5HCl+SiCl4. Gaseous chlorosilane, hydrogen and a large amount of amorphous silicon powder are produced during the chemical vapor deposition process. In the process of recovering gaseous chlorosilane and hydrogen, amorphous silicon powder can easily cause wear of the tail gas recovery condensation equipment, leading to leakage, equipment blockage and a short replacement cycle of the compressor wearing parts of the compressor system. Utility Model Content

[0003] In view of this, the utility model provides a system for processing amorphous silicon powder in electronic-grade polysilicon tail gas, the main purpose of which is to remove the amorphous silicon powder in the reduction tail gas and reduce the failure rate of the tail gas recovery unit equipment.

[0004] In order to achieve the above purpose, the utility model mainly provides the following technical solutions:

[0005] The utility model provides a system for processing amorphous silicon powder in electronic-grade polysilicon tail gas, the system comprising: a tower body and a separation part;

[0006] The upper end of the tower body is connected to the exhaust pipe, and the lower end of the tower body is connected to the filter;

[0007] The separation part includes a spray mechanism and a cyclone separation mechanism, and the spray mechanism and the cyclone separation mechanism are arranged in sequence from top to bottom inside the tower body. The spray mechanism includes a spray structure and a packing structure arranged in sequence from top to bottom. The tangential inlet pipe of the cyclone separation mechanism passes through the side wall of the tower body, and the upper end outlet of the cyclone separation mechanism is provided with a cover body for preventing the spray liquid from entering the cyclone separation mechanism through the upper end outlet.

[0008] The purpose of the utility model and the solution to its technical problems can also be further achieved by adopting the following technical measures.

[0009] Optionally, the cover body is a spherical cover body, and the edge of the spherical cover body is fixedly connected to the edge of the upper outlet through a plurality of support rods.

[0010] Optionally, the spray structure includes an infusion tube and a plurality of spray tubes connected to the lower wall of the infusion tube.

[0011] Optionally, the filler structure includes a support plate, a filler and a pressure plate arranged in sequence from bottom to top, the upper surface of the support plate is evenly distributed with a plurality of support tubes, the tube walls of the support tubes are evenly distributed with a plurality of air holes, the upper surface of the pressure plate is arranged with a plurality of overflow grooves, and the plurality of overflow grooves and the plurality of spray pipes are staggered with each other.

[0012] Optionally, the lower end of the tower body is connected to the inlet end of the filter, and the outlet end of the filter is connected to the distillation unit and the liquid infusion pipe.

[0013] Optionally, the filter includes a first filter and a second filter connected in parallel, an outlet end of the first filter and an outlet end of the second filter are respectively connected to a backwash pipe, and a slag discharge port of the filter is connected to a slurry unit.

[0014] Optionally, the filter is provided with a differential pressure sensor.

[0015] By means of the above technical solution, the utility model has at least the following advantages:

[0016] The reduction furnace tail gas containing amorphous silicon powder enters the cyclone separation mechanism through the tangential inlet pipe. The heavy component and the silicon powder with larger particle size spirally settle in the shell of the cyclone separation mechanism, and the light component and the silicon powder with smaller particle size are discharged from the upper end outlet along with the tail gas, and pass over the edge of the cover and rise upward.

[0017] At the same time, the spray structure sprays out spray liquid, and the spray liquid and tail gas contact in countercurrent in the packing structure, silicon powder with smaller particle size is washed away, and the cleaned reduction furnace tail gas enters the tail gas recovery unit through the exhaust pipe.

[0018] At the same time, since the cover covers the upper outlet of the cyclone separation mechanism, the downward-flowing spray liquid is prevented from entering the cyclone separation mechanism from the upper outlet, and the spiral airflow in the cyclone separation mechanism will not be affected by the spray liquid, thereby ensuring that silicon powder with larger particle size can be successfully separated in the cyclone separation mechanism.

[0019] After the above treatment process, the probability of silicon powder wearing out the condensing equipment is reduced, leakage is avoided, and silicon powder is prevented from clogging the equipment, which extends the replacement cycle of the compressor wearing parts and reduces the failure rate of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a system for processing amorphous silicon powder in tail gas of electronic-grade polysilicon provided by an embodiment of the utility model;

[0021] Figure 2 for Figure 1 A magnified view of part A;

[0022] Figure 3A top view of the pressure plate.

[0023] The figure marks in the drawings of the specification include: tower body 1, exhaust pipe 2, cyclone separation mechanism 3, cover body 4, support rod 5, infusion pipe 6, spray pipe 7, support plate 8, pressing plate 9, support pipe 10, air vent 11, overflow trough 12, first filter 13, second filter 14, backwash pipe 15, output pipe 16, distillation main pipe 17, slag discharge port 18, differential pressure sensor 19. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0025] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0026] like Figure 1 As shown, an embodiment of the utility model provides a system for processing amorphous silicon powder in electronic-grade polysilicon tail gas, which comprises: a tower body 1 and a separation part;

[0027] The upper end of the tower body 1 is connected to the exhaust pipe 2, and the lower end of the tower body 1 is connected to the filter;

[0028] The separation part includes a spray mechanism and a cyclone separation mechanism 3, which are arranged in sequence from top to bottom inside the tower body 1. The spray mechanism includes a spray structure and a packing structure arranged in sequence from top to bottom. The tangential inlet pipe of the cyclone separation mechanism 3 passes through the side wall of the tower body 1, and the upper end outlet of the cyclone separation mechanism 3 is provided with a cover body 4 for preventing the spray liquid from entering the cyclone separation mechanism 3 through the upper end outlet.

[0029] The working process of a system for treating amorphous silicon powder in tail gas of electronic grade polysilicon is as follows:

[0030] The reduction furnace tail gas containing amorphous silicon powder enters the cyclone separation mechanism 3 through the tangential inlet pipe, and the heavy component and the silicon powder with larger particle size spirally settle in the shell of the cyclone separation mechanism 3, and the light component and the silicon powder with smaller particle size are discharged from the upper end outlet along with the tail gas, and pass over the edge of the cover body 4 and rise upward.

[0031] At the same time, the spray structure sprays out spray liquid, and the spray liquid and tail gas contact in countercurrent in the packing structure, silicon powder with smaller particle size is washed away, and the cleaned reduction furnace tail gas enters the tail gas recovery unit through the exhaust pipe 2.

[0032] At the same time, since the cover body 4 covers the upper outlet of the cyclone separation mechanism 3, the downwardly flowing spray liquid is prevented from entering the cyclone separation mechanism 3 from the upper outlet, and the spiral airflow in the cyclone separation mechanism 3 will not be affected by the spray liquid, thereby ensuring that silicon powder with larger particle size can be successfully separated in the cyclone separation mechanism 3.

[0033] After the above treatment process, the probability of silicon powder in the exhaust gas wearing out the condensing equipment of the exhaust gas recovery unit is reduced, leakage is avoided, and silicon powder is prevented from clogging the equipment, extending the replacement cycle of the compressor wearing parts and reducing the failure rate of the equipment.

[0034] Specifically, the spray liquid is chlorosilane liquid.

[0035] Specifically, the cyclone separation mechanism 3 and the spray mechanism cooperate with each other to efficiently remove the amorphous silicon powder in the tail gas.

[0036] In a specific embodiment, the cover body 4 is a spherical cover body 4 , and the edge of the spherical cover body 4 is fixedly connected to the edge of the upper outlet through a plurality of support rods 5 .

[0037] In this embodiment, specifically, the spray liquid is eluted to the spherical cover body 4, flows along the curved surface of the spherical cover body 4 toward the edge of the cover body 4, and finally settles to the bottom of the tower body 1; at the same time, there is a gap between adjacent support rods 5, and the tail gas removing the larger particles of silicon powder passes through the gap and then passes over the spherical cover body 4, rising upward, and the gas-solid separation process and the downward flow of the spray liquid do not interfere with each other.

[0038] like Figure 1 As shown, in a specific embodiment, the spray structure includes a liquid infusion tube 6 and a plurality of spray tubes 7 connected to the lower wall of the liquid infusion tube 6 .

[0039] In this embodiment, specifically, the liquid infusion pipe 6 is horizontally arranged above the interior of the tower body 1, and the inlet end of the liquid infusion pipe 6 passes through the side wall of the tower body 1, which is used to drain the external spray liquid into the tower body 1 and spray it to the packing structure through the spray pipe 7.

[0040] like Figures 1 to 3 As shown, in a specific embodiment, the filler structure includes a support plate 8, a filler and a pressure plate 9 arranged in sequence from bottom to top, a plurality of support tubes 10 are evenly distributed on the upper surface of the support plate 8, a plurality of air holes 11 are evenly distributed on the tube wall of the support tube 10, a plurality of overflow grooves 12 are arranged on the upper surface of the pressure plate 9, and the plurality of overflow grooves 12 and the plurality of spray pipes 7 are staggered with each other.

[0041] In this embodiment, the packing is a rectangular saddle ring, 80*40*0.5 (outer diameter*height*thickness mm), and the number of stacking is 5800 / m 3 , bulk density 148kg / m 3 , specific surface area 74.9m2 / m 3 , porosity 0.96.

[0042] In this embodiment, a plurality of first mounting ports are provided on the surface of the support plate 8, the lower end of the support tube 10 is welded to the first mounting port, a plurality of second mounting ports are provided on the surface of the pressing plate 9, and the lower end of the overflow groove 12 is welded to the second mounting port; the spray liquid sprayed from the spray pipe 7 is first deposited above the pressing plate 9, and when the liquid level of the spray liquid rises to the upper end of the overflow groove 12, the spray liquid passes through the second mounting port and contacts the filler.

[0043] Meanwhile, compared with the case where a plurality of air holes 11 are directly provided on the support plate 8 , a plurality of air holes 11 are evenly distributed on the tube wall of the support tube 10 , and the packing structure can arrange more air holes 11 .

[0044] Specifically, the diameter of the support tube 10 gradually decreases from top to bottom, so that the tube wall of the support tube 10 can share a part of the weight of the stacked filler.

[0045] Through the above structure, the spray liquid first contacts the pressing plate 9 and then overflows the upper end of the overflow groove 12, consuming the kinetic energy of the spray liquid just leaving the spray pipe 7, thereby preventing the spray liquid from violently impacting the filler and destroying the stacking structure of the filler.

[0046] like Figure 1 As shown, in a specific embodiment, the lower end of the tower body 1 is connected to the inlet end of the filter, and the outlet end of the filter is connected to the distillation unit and the liquid infusion pipe 6.

[0047] In the present embodiment, specifically, after the filtering action of the filter, the silicon powder is intercepted to produce a relatively clean chlorosilane liquid component, a part of the chlorosilane liquid enters the distillation unit for multi-stage distillation, thereby reducing the difficulty of the distillation treatment; another part of the chlorosilane liquid component reaches the infusion pipe 6 and is again used as a spray liquid to wash the reduction furnace exhaust gas.

[0048] like Figure 1 As shown, in a specific embodiment, the filter includes a first filter 13 and a second filter 14 connected in parallel, the outlet end of the first filter 13 and the outlet end of the second filter 14 are respectively connected to a backwash pipe 15, and the slag discharge port 18 of the filter is connected to a slurry unit.

[0049] In this embodiment, specifically, the upper head of the first filter 13 and the upper head of the second filter 14 are respectively connected to one end of the backwash pipe 15 and one end of the output pipe 16, and the other end of the backwash pipe 15 and the other end of the output pipe 16 are connected to the distillation main pipe 17.

[0050] When the pressure difference of the first filter 13 is large, the operator can switch the first filter 13 to the second filter 14, and then open the slag discharge port 18 valve and the backwash pipe 15 valve of the first filter 13 to flush and discharge the silicon powder in the first filter 13 to the slurry unit. The slurry unit heats the chlorosilane in the backwash liquid through a spiral dryer for recovery, and also safely and environmentally recovers the amorphous silicon powder in the backwash liquid, so that the filter element of the first filter 13 is restored to cleanliness and the switched first filter 13 is in standby state.

[0051] like Figure 1 As shown, in a specific embodiment, the filter is provided with a differential pressure sensor 19 .

[0052] In this embodiment, specifically, the differential pressure sensor 19 is integrated into the DCS control system, so that the operator can remotely control the differential pressure and backwash time of the filter, control the filter inlet valve, outlet valve, and slag discharge port 18 valve, and circulate the filter backwash and put it into use.

[0053] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A system for processing amorphous silicon powder in electronic grade polysilicon tail gas, characterized in that: include: A tower body, wherein the upper end of the tower body is connected to the exhaust pipe, and the lower end of the tower body is connected to the filter; The separation part comprises a spray mechanism and a cyclone separation mechanism, the spray mechanism and the cyclone separation mechanism are arranged in sequence from top to bottom inside the tower body, the spray mechanism comprises a spray structure and a packing structure arranged in sequence from top to bottom, the tangential inlet pipe of the cyclone separation mechanism passes through the side wall of the tower body, and the upper end outlet of the cyclone separation mechanism is provided with a cover body for preventing the spray liquid from entering the cyclone separation mechanism through the upper end outlet.

2. The system for processing amorphous silicon powder in electronic-grade polysilicon tail gas according to claim 1, characterized in that: The cover body is a spherical cover body, and the edge of the spherical cover body is fixedly connected to the edge of the upper end outlet through a plurality of support rods.

3. The system for processing amorphous silicon powder in electronic-grade polysilicon tail gas according to claim 1, characterized in that: The spray structure comprises a liquid infusion pipe and a plurality of spray pipes connected to the lower side wall of the liquid infusion pipe.

4. The system for processing amorphous silicon powder in electronic-grade polysilicon tail gas according to claim 3, characterized in that: The packing structure includes a support plate, a packing and a pressure plate arranged in sequence from bottom to top, a plurality of support tubes are evenly distributed on the upper surface of the support plate, a plurality of air holes are evenly distributed on the tube wall of the support tube, a plurality of overflow grooves are arranged on the upper surface of the pressure plate, and the plurality of overflow grooves and the plurality of spray pipes are staggered with each other.

5. The system for processing amorphous silicon powder in electronic-grade polysilicon tail gas according to claim 3, characterized in that: The lower end of the tower body is connected to the inlet end of the filter, and the outlet end of the filter is connected to the distillation unit and the liquid infusion pipe.

6. The system for processing amorphous silicon powder in electronic-grade polysilicon tail gas according to claim 5, characterized in that: The filter comprises a first filter and a second filter connected in parallel with each other, the outlet end of the first filter and the outlet end of the second filter are respectively connected to the backwash pipe, and the slag discharge port of the filter is connected to the slurry unit.

7. The system for processing amorphous silicon powder in electronic-grade polysilicon tail gas according to claim 5, characterized in that: The filter is provided with a differential pressure sensor.

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