CN217895155U - On-line silicon powder discharging system for fluidized bed - Google Patents
On-line silicon powder discharging system for fluidized bed Download PDFInfo
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- CN217895155U CN217895155U CN202222184433.XU CN202222184433U CN217895155U CN 217895155 U CN217895155 U CN 217895155U CN 202222184433 U CN202222184433 U CN 202222184433U CN 217895155 U CN217895155 U CN 217895155U
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Abstract
The utility model discloses an online row silica flour system for fluidized bed belongs to polycrystalline silicon cold hydrogenation production technical field. The device comprises a silicon powder storage tank and a silicon powder filter which are connected with a hydrogenation furnace, wherein the lower part of the hydrogenation furnace is provided with a silicon powder discharge port, and the silicon powder discharge port is connected with a feed inlet of the silicon powder storage tank through a silicon powder discharge pipe; the top of the silicon powder storage tank is connected with the silicon powder filter through an exhaust gas phase pipe, the top of the silicon powder filter is connected with the top of the hydrogenation furnace through a gas phase recycling pipe, and a gas phase recycling circulation passage in the online silicon powder exhaust process is formed among the silicon powder exhaust pipe, the silicon powder storage tank, the exhaust gas phase pipe, the silicon powder filter and the gas phase recycling pipe; the bottom of the silicon powder filter is connected with the silicon powder storage tank through a silicon powder return pipe, and a continuous path for online silicon powder discharge is formed among the exhaust gas phase pipe, the silicon powder filter and the silicon powder return pipe. Ensures the continuous operation of the polysilicon production and reduces the production cost.
Description
Technical Field
The utility model relates to a row's silica flour system especially relates to an online row's silica flour system for fluidized bed, belongs to polycrystalline silicon cold hydrogenation production technical field.
Background
At present, the main process technologies for producing polycrystalline silicon at home and abroad include an improved siemens method, a silane method, a fluidized bed method, a metallurgical method (a physical method) and the like, wherein the improved siemens method is generally recognized as the most mature process technology for purifying polycrystalline silicon, accounts for more than 75% of the total yield, and according to statistics, 40 of 44 large-scale projects which are built and operated at home are improved siemens methods.
The improved siemens method is the mainstream process of the existing polysilicon production, and the cold hydrogenation is the core process, mainly comprising the following steps: industrial silicon powder and silicon tetrachloride are converted into trichlorosilane under high temperature and high pressure in a fluidized bed reactor, the trichlorosilane is treated in a multistage rectifying tower to remove impurities, refined trichlorosilane required by reduction is obtained, and the material is reduced into a final product of polycrystalline silicon by adding hydrogen in a reduction furnace reactor. After the cold hydrogenation fluidized bed operates for a period of time, the cold hydrogenation fluidized bed needs to be stopped for maintenance, and inactivated silicon powder in the fluidized bed is removed. At present, the waste contact body tank adopted can only discharge slag during parking, but cannot realize online silicon powder discharge, the parking can influence the balance of materials in the whole plant, the cost is increased when the vehicle is started and stopped, and the continuous operation of the process cannot be ensured. Under the background of high price of polysilicon, great benefit loss of enterprises is inevitable.
The continuous operation of the cold hydrogenation process is ensured, namely the low efficiency of the polysilicon production process, the low quality of polysilicon products and the like.
In the prior art, CN209890259U discloses a "polysilicon production device without generating slurry", wherein, a "fine powder collection tank is connected with a discharge port at the top of a fluidized bed reactor, the top of the fine powder collection tank is open and is provided with a metal filter, and fine powder in synthesis gas discharged by the fluidized bed reactor is trapped and collected in the fine powder collection tank through the metal filter; the top feed port of the fine silicon powder recovery tank is connected with the bottom discharge port of the fine powder collection tank, and the bottom discharge port of the fine silicon powder recovery tank is connected with the other feed port at the bottom of the fluidized bed reactor; the fine powder collecting tank guides the collected fine powder into the fine silicon powder recovery tank, and the fine powder is guided into the fluidized bed reactor for recycling through the fine silicon powder recovery tank, so that the problems of pipeline and equipment blockage in the subsequent cold hydrogenation are solved, dust removal and slag slurry recovery facilities are reduced, the operation period of a cold hydrogenation system is prolonged, the silicon powder consumption is reduced, and the generation of a large amount of three wastes and the investment of environment-friendly facilities are reduced. CN106904618A discloses a method and a system for on-line recovery of silicon powder in cold hydrogenation reaction tail gas, wherein the silicon powder in the cold hydrogenation reaction tail gas is recovered. CN106554018A discloses a "cold hydrogenation dust removal system and process", wherein a cyclone separator, a gas-gas heat exchanger and a filter are connected in series to perform dry dust removal, silicon powder dust in fluidized bed reaction gas is separated and recovered into a fluidized bed, the reaction gas is conveyed to a washing tower for wet dust removal after the dry dust removal, and the washing and dust removal are performed immediately after the cyclone dust removal and the filter dust removal.
Disclosure of Invention
The utility model discloses based on current cold hydrogenation technology, in order to solve the not enough of prior art to and, guarantee the continuous operation of polycrystalline silicon production, reduction in production cost provides an online row silica flour system for fluidized bed.
In order to achieve the technical purpose, the following technical scheme is proposed:
an online silicon powder discharge system for a fluidized bed comprises a silicon powder storage tank and a silicon powder filter, wherein the silicon powder storage tank and the silicon powder filter are connected with a hydrogenation furnace, a silicon powder discharge port is formed in the lower portion of the hydrogenation furnace, and the silicon powder discharge port is connected with a feeding hole of the silicon powder storage tank through a silicon powder discharge pipe; the top of the silicon powder storage tank is connected with the silicon powder filter through an exhaust gas phase pipe, the top of the silicon powder filter is connected with the top of the hydrogenation furnace through a gas phase recycling pipe, and a gas phase recycling circulation passage in the online silicon powder exhaust process is formed among the silicon powder exhaust pipe, the silicon powder storage tank, the exhaust gas phase pipe, the silicon powder filter and the gas phase recycling pipe;
the bottom of the silicon powder filter is connected with the silicon powder storage tank through a silicon powder return pipe, and a continuous path for online silicon powder discharge is formed among the exhaust gas phase pipe, the silicon powder filter and the silicon powder return pipe.
Furthermore, the silicon powder discharging pipe is made of 800H materials, so that high temperature resistance and high pressure resistance are realized. In the hydrogenation furnace, the conditions involved are generally 2.4 to 3.0MPa and 530 to 570 ℃ and the main reactions involved are as follows: 3SiCl 4 +Si+2H 2 =4SiHCl 3 And Q (endothermic reaction), based on the limitation of the 800H silicon powder discharge pipe, the influence of online discharged inactive silicon powder (specifically, gas phase carried by large-particle-size silicon powder, small-particle-size silicon powder and silicon powder, wherein the gas phase comprises trichlorosilane, dichlorosilane, hydrogen and silicon tetrachloride) on the silicon powder discharge pipe is prevented, the service life of the silicon powder discharge pipe is further prolonged, and the stability of the system is improved.
Furthermore, the outside cover of silica flour storage tank is equipped with the heat transfer and presss from both sides the cover, and the heat transfer presss from both sides the cover and is connected with the refrigerant and advances pipe and refrigerant exit tube, and this setting is to carrying out cooling treatment to the deactivation silica flour of arranging, is convenient for carry out subsequent silica flour and filters and retrieve.
Furthermore, the feeding hole of the silicon powder storage tank is arranged at the upper part of the silicon powder storage tank, the bottom of the silicon powder storage tank is connected with an outer silicon powder discharge pipe, and the collected inactivated silicon powder is treated and then recycled.
Further, silica flour storage tank is connected with vacuum apparatus, and vacuum apparatus includes accessory parts such as vacuum pump, should set up, when guaranteeing to shut down cold hydrogenation system, provides vacuum power for the discharge of the interior deactivation silica flour of stove, is about to take out the deactivation silica flour in the hydrogenation stove, and it is used for assisting this online row silica flour system, and then improves the practicality and the application scope of this online row silica flour system.
Furthermore, the filtering precision of the silicon powder filter is less than or equal to 1 mu m, and the silicon powder cut rate is more than 99.99 percent.
Furthermore, the lower part of the silicon powder filter is connected with a nitrogen inlet pipe, so that the silicon powder in the silicon powder filter is swept into the silicon powder storage tank, and the silicon powder is prevented from flowing backwards and the like; the nitrogen inlet pipe is also connected with the top of the silicon powder filter through a branch pipe, so that the silicon powder in the silicon powder filter is subjected to back flushing, and the normal work of the silicon powder filter is ensured.
Furthermore, the gas phase recycling pipe is provided with a vent pipe, so that the stability of the air pressure of the circulating passage is maintained, and the stability and sustainability of the processes related to the system are improved.
In the technical scheme, a manual valve and an adjusting valve are arranged on the corresponding pipeline according to actual requirements.
The positional relationships such as "lower portion", "top portion", "between portion", "upper portion", "bottom portion" and the like in the present technical solution are defined according to the actual usage state, and are conventional terms in the technical field and also conventional terms during actual usage by those skilled in the art.
By adopting the technical scheme, the beneficial technical effects brought are as follows:
the utility model is provided with a silicon powder discharge port at the lower part of the hydrogenation furnace, and the silicon powder discharge port is connected with a silicon powder storage tank feed inlet through a silicon powder discharge pipe; the top of the silicon powder storage tank is connected with the silicon powder filter through the exhaust gas phase pipe, and the top of the silicon powder filter is connected with the top of the hydrogenation furnace through the gas phase recycling pipe, so that a circulation passage for gas phase recycling in the on-line silicon powder exhaust process is formed among the silicon powder exhaust pipe, the silicon powder storage tank, the exhaust gas phase pipe, the silicon powder filter and the gas phase recycling pipe;
the bottom of the silicon powder filter is connected with the silicon powder storage tank through a silicon powder return pipe, so that a continuous path for online silicon powder discharge is formed among the exhaust gas phase pipe, the silicon powder filter and the silicon powder return pipe;
the influence of cold hydrogenation parking on the whole production line is effectively reduced, the on-line discharge of deactivated silicon powder is realized, the gas phase in the process is recycled, the reasonable utilization of resources is improved, and the problems that the production capacity of an enterprise is influenced by the waste silicon powder needing to be parked and the parking cost is increased in the prior art are solved.
Drawings
FIG. 1 is a schematic flow chart of the present invention;
in the figure, 1, a hydrogenation furnace, 2, a silicon powder storage tank, 3, a silicon powder filter, 4, a silicon powder discharge port, 5, a silicon powder discharge pipe, 6, an exhaust gas phase pipe, 7, a gas phase recycling pipe, 8, a silicon powder return pipe, 9, a heat exchange jacket, 10, a refrigerant inlet pipe, 11, a refrigerant outlet pipe, 12, a silicon powder discharge pipe, 13, a vacuum device, 14, a nitrogen inlet pipe, 15, a branch pipe, 16 and a blow-down pipe.
Detailed Description
In the following, the technical solutions in the embodiments of the present invention are clearly and completely described, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Example 1
As shown in fig. 1: an online silicon powder discharge system for a fluidized bed comprises a silicon powder storage tank 2 and a silicon powder filter 3 which are connected with a hydrogenation furnace 1, wherein a silicon powder discharge port 4 is formed in the lower part of the hydrogenation furnace 1, and the silicon powder discharge port 4 is connected with a feed inlet of the silicon powder storage tank 2 through a silicon powder discharge pipe 5; the top of the silicon powder storage tank 2 is connected with the silicon powder filter 3 through the gas-phase exhaust pipe 6, the top of the silicon powder filter 3 is connected with the top of the hydrogenation furnace 1 through the gas-phase recycling pipe 7, and a gas-phase recycling circulation passage in the online silicon powder exhaust process is formed among the silicon powder exhaust pipe 5, the silicon powder storage tank 2, the gas-phase exhaust pipe 6, the silicon powder filter 3 and the gas-phase recycling pipe 7;
the bottom of the silicon powder filter 3 is connected with the silicon powder storage tank 2 through a silicon powder return pipe 8, and a continuous path for online discharging silicon powder is formed among the gas exhaust gas phase pipe 6, the silicon powder filter 3 and the silicon powder return pipe 8.
In the technical scheme, the related process flow is as follows:
1. in the hydrogenation furnace 1, the cold hydrogenation process involved comprises: the vaporized silicon tetrachloride is mixed with hydrogen to form mixed gas, the mixed gas is heated by an electric heater, meanwhile, raw material silicon powder in a hydrogenation furnace 1 is relatively uniformly suspended in a fluidized bed through a distributor, and the heated mixed gas reacts with the raw material silicon powder under the conditions of 2.4-3.0Mpa and 530-570 ℃ to generate mixed gas containing trichlorosilane, dichlorosilane and silicon tetrachloride (silicon powder and hydrogen are also mixed in the mixed gas); wherein, in order to maintain the reaction temperature in the fluidized bed, the electric heater is mainly used for heating. After the fluidized bed runs for a period of time, the inactive silicon powder is accumulated at the lower part of the hydrogenation furnace 1, and in order to ensure the stability, sustainability and high efficiency of the cold hydrogenation process of the hydrogenation furnace 1, the online silicon powder discharge is realized based on the online silicon powder discharge system;
2. in combination with the material balance of the cold hydrogenation process, the gas phase (gas phase comprises mixed gas of trichlorosilane, dichlorosilane, hydrogen and silicon tetrachloride) which is carried by the large-particle-size silicon powder, the small-particle-size silicon powder and the silicon powder is discharged into a silicon powder storage tank 2 through a silicon powder discharge pipe 5;
3. in the silicon powder storage tank 2, large-particle-size silicon powder is deposited, and gas phase mixed with small-particle-size silicon powder is gathered to the top of the silicon powder storage tank 2; then the silicon powder is discharged into the silicon powder filter 3 through the gas exhaust pipe 6, the silicon powder with small particle size is intercepted and deposited at the bottom of the silicon powder filter 3 through the filtration of a filter element, and the silicon powder returns to the silicon powder storage tank 2 through the silicon powder return pipe 8, and finally the silicon powder with large particle size is discharged outside together, and the treated silicon powder is reused; the gas phase returns to the hydrogenation furnace 1 from the gas phase recycling pipe 7 and then participates in the cold hydrogenation process;
wherein, in the reflux of the small-particle-size silicon powder, purging can be carried out through nitrogen without blocking a pipeline; meanwhile, the nitrogen is blown back to the filter element in the silicon powder filter 3, so that the service life of the filter element is prolonged, the filtering efficiency is improved, and the like.
Example 2
Based on example 1, this example further defines the deactivated silicon powder discharged on-line under the high-temperature and high-pressure condition of the hydrogenation furnace 1, so as to further explain the technical scheme.
Wherein, arrange silica flour pipe 5 for the silica flour pipe 5 of 800H material, realize high temperature resistant and high pressure resistant. In the hydrogenation furnace 1, the conditions involved are generally between 2.4 and 3.0MPa and between 530 and 570 ℃ and the main reactions involved are as follows: based on the limitation of the 800H silicon powder discharge pipe 5, the influence of online discharged inactivated silicon powder (specifically, large-particle-size silicon powder, small-particle-size silicon powder and gas phase carried by the silicon powder, wherein the gas phase comprises mixed gas of trichlorosilane, dichlorosilane, hydrogen and silicon tetrachloride) on the silicon powder discharge pipe 5 is prevented, the service life of the system is further prolonged, and the stability of the system is improved.
And, the outside cover of above-mentioned silica flour storage tank 2 is equipped with heat exchange jacket 9, and heat exchange jacket 9 is connected with refrigerant and advances pipe 10 and refrigerant exit tube 11, and this setting mainly carries out the cooling treatment to the deactivation silica flour of arranging, is convenient for carry out subsequent silica flour and filters and retrieve.
In addition, the feeding hole of the silicon powder storage tank 2 is arranged at the upper part of the silicon powder storage tank 2, the bottom of the silicon powder storage tank 2 is connected with an outer silicon powder discharge pipe 12, and the collected inactivated silicon powder is treated and reused.
Example 3
Based on examples 1-2, this example further defines how to discharge the deactivated silicon powder when the hydrogenation furnace 1 is stopped, so as to further explain the technical scheme.
Silica flour storage tank 2 is connected with vacuum apparatus 13, and vacuum apparatus 13 includes vacuum pump and accessory part, and this setting is guaranteed when cold hydrogenation system parks, provides vacuum power for devitalizing silica flour in arranging hydrogenation furnace 1, is about to take the devitalizing silica flour in hydrogenation furnace 1 out, and it is used for assisting this online row silica flour system, and then improves practicality and the application scope of this online row silica flour system.
Example 4
Based on examples 1 to 3, the present example further defines the silicon powder filter 3 to further describe the technical solution.
Wherein, the filtering precision of the silicon powder filter 3 is less than or equal to 1 μm, and the silicon powder cut-off rate is more than 99.99 percent.
In addition, the lower part of the silicon powder filter 3 is connected with a nitrogen inlet pipe 14, so that silicon powder in the silicon powder filter 3 is conveyed into the silicon powder storage tank 2, and the silicon powder is prevented from flowing backwards and the like; the nitrogen inlet pipe 14 is also connected with the top of the silicon powder filter 3 through a branch pipe 15, so that the silicon powder in the silicon powder filter 3 is subjected to back flushing, and the silicon powder interception rate of the silicon powder filter 3 is improved.
Example 5
The present embodiment will be further described with reference to the following embodiments 1 to 4, which are intended to further limit the process of recycling the gaseous phase.
Wherein, gas phase retrieval and utilization pipe 7 is equipped with blow-down pipe 16, maintains the atmospheric pressure of circulation route stable, improves the stability and the sustainability of the process that this system relates to promptly.
Claims (7)
1. The utility model provides an online row silica flour system for fluidized bed which characterized in that: the device comprises a silicon powder storage tank (2) and a silicon powder filter (3) which are connected with a hydrogenation furnace (1), wherein a silicon powder discharge port (4) is formed in the lower part of the hydrogenation furnace (1), and the silicon powder discharge port (4) is connected with a feed inlet of the silicon powder storage tank (2) through a silicon powder discharge pipe (5); the top of the silicon powder storage tank (2) is connected with the silicon powder filter (3) through an exhaust gas phase pipe (6), the top of the silicon powder filter (3) is connected with the top of the hydrogenation furnace (1) through a gas phase recycling pipe (7), and a circulation passage for gas phase recycling in the on-line silicon powder exhaust process is formed among the silicon powder exhaust pipe (5), the silicon powder storage tank (2), the exhaust gas phase pipe (6), the silicon powder filter (3) and the gas phase recycling pipe (7);
the bottom of the silicon powder filter (3) is connected with the silicon powder storage tank (2) through a silicon powder return pipe (8), and a continuous path for online discharging silicon powder is formed among the exhaust gas phase pipe (6), the silicon powder filter (3) and the silicon powder return pipe (8).
2. The on-line silicon powder discharge system for a fluidized bed according to claim 1, characterized in that: the silicon powder discharge pipe (5) is made of 800H materials.
3. The on-line silicon powder discharge system for a fluidized bed according to claim 1 or 2, characterized in that: the outside cover of silica flour storage tank (2) is equipped with heat transfer and presss from both sides cover (9), and heat transfer presss from both sides cover (9) and is connected with refrigerant and advances pipe (10) and refrigerant exit tube (11).
4. The on-line silicon powder discharging system for the fluidized bed as set forth in claim 3, characterized in that: the feeding hole of the silicon powder storage tank (2) is formed in the upper portion of the silicon powder storage tank (2), and the bottom of the silicon powder storage tank (2) is connected with an outer silicon powder discharge pipe (12).
5. The on-line silicon powder discharge system for a fluidized bed according to claim 1, characterized in that: the silicon powder storage tank (2) is connected with a vacuum device (13), and the vacuum device (13) comprises a vacuum pump.
6. The on-line silicon powder discharging system for the fluidized bed according to claim 1, characterized in that: the filtering precision of the silicon powder filter (3) is less than or equal to 1 mu m.
7. The on-line silicon powder discharging system for the fluidized bed according to claim 1, characterized in that: the lower part of the silicon powder filter (3) is connected with a nitrogen inlet pipe (14), and the nitrogen inlet pipe (14) is also connected with the top of the silicon powder filter (3) through a branch pipe (15).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202222184433.XU CN217895155U (en) | 2022-08-18 | 2022-08-18 | On-line silicon powder discharging system for fluidized bed |
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| CN202222184433.XU CN217895155U (en) | 2022-08-18 | 2022-08-18 | On-line silicon powder discharging system for fluidized bed |
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