CN203173826U - Cold wall fluidized bed - Google Patents
Cold wall fluidized bed Download PDFInfo
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- CN203173826U CN203173826U CN 201320171511 CN201320171511U CN203173826U CN 203173826 U CN203173826 U CN 203173826U CN 201320171511 CN201320171511 CN 201320171511 CN 201320171511 U CN201320171511 U CN 201320171511U CN 203173826 U CN203173826 U CN 203173826U
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Abstract
The utility model relates to a cold wall fluidized bed, belonging to the field of polycrystalline silicon preparation technology. The cold wall fluidized bed comprises a fluidized bed; the lower end of the fluidized bed is provided with a gas mixer; the gas mixer is connected with a discharge pipeline; the discharge pipeline is sequentially provided with a second raw material gas inlet and a first raw material gas inlet, wherein the lower end of the first raw material gas inlet is also provided with an outlet valve; and an exit is arranged under the outlet valve. The high-purity granular solar grade polycrystalline silicon is prepared by taking the cold wall fluidized bed as basis, and the production process is simple and convenient, so that the cold wall fluidized bed is suitable for industrial production.
Description
Technical field
The utility model relates to a kind of cold wall fluidized-bed, is specifically related to a kind of cold wall fluidized-bed for the preparation of high purity particulate state solar-grade polysilicon through improvement, belongs to the polysilicon preparing technical field.
Background technology
High-purity polycrystalline silicon is widely used in microelectronics, photoelectron, and industries such as solar cell are electronic information and solar-energy photo-voltaic cell industry basic raw material.At present, preparation polysilicon mainstream technology is the improvement Siemens Method both at home and abroad, the bell-jar reactor can be prepared the thick rod-like polycrystal silicon of diameter 50～300mm, owing to be subjected to the restriction of silicon rod maximum diameter, can not operate continuously, because be subjected to the influence of silicon rod specific surface area and calorific loss, reactor siliceous deposits efficient is low; Because international technology blocks, domestic most of silicon material producer does not also successfully grasp the hydrogenation of silicon tetrachloride technology, and part producer even can't accomplish the material recycle to extinction causes environmental pollution, the general technical situation is energy consumption height, cost height, and a lot of enterprises are in stopping production, bankruptcy status.
Study many silane fluidized bed process and trichlorosilane (SiHCl recently
3) fluidized bed process prepares polysilicon, and technological deficiency is separately arranged.The silane fluidized bed process adopts SiH
4For unstripped gas in high temperature fluidized bed at high temperature silica flour surface deposition polysilicon, the preparation SiH
4Approaches and methods have multiplely, mainly contain Si-Mg alloy method, organoalkoxysilane method, silicon tetrafluoride/silicon tetrachloride (SiF at present both at home and abroad
4/ SiCl
4) method and UCC method.Though the temperature lower (600～800 ℃) of silane fluidized bed process reaction, and the efficient that is converted into polysilicon of silane can reach more than 80%, but, silane gas is inflammable and explosive, very easily leaks, and factory all once took place for preparation silane and use silane producer ruins the explosive incident that the people dies, abnormally dangerous, and silane is not easy preparation, and there is technological deficiency in the preparation technology of every kind of silane.The Si-Mg alloy legal system that with the Zhejiang University is representative is equipped with the silane gas Technology, at home little factory is many, the cost height, silane purity is low, be difficult to reach the technical requirements of solar battery sheet, more serious technical problem is owing to adopt tank reactor, can not serialization production, and can not scale operation.Organoalkoxysilane prepares silane gas, and the silane purity of preparation is the highest, and still, amount of by-products is bigger, if by product can not deep processing, is seriously restricting large-scale production.Silicon fluoride/silicon tetrachloride (SiF
4/ SiCl
4) though legal system is equipped with silane at home and abroad has and produce house and go into operation producing or prepare,, can generate a large amount of HF, HCl gas in the production engineering, environmental pollution is serious.Though the UCC legal system is equipped with silane foreign technology comparative maturity, also be the mainstream technology for preparing granulated polycrystalline silicon at present both at home and abroad, need use SiHCl
3Or SiCl
4Add catalyzer hydrogenation, reduce step by step with hydrogen, finally generate SiH
4, the reaction process flow process is longer, from SiHCl
3Reduction preparation SiH
2Cl
2A transformation efficiency is less than 30%, from SiH
2Cl
2To SiH
4A transformation efficiency is less than 25%, from SiHCl
3To SiH
4One time transformation efficiency is very low, and the circulation that needs material not stop in system is so the reduction energy consumption is higher.
SiHCl
3Fluidized bed process also is one of technology of heat, the more satisfactory preparation granulated polycrystalline silicon of research both at home and abroad at present.SiHCl
3It mainly is to adopt external heating type " hot wall fluidized-bed " that fluidized bed process prepares polysilicon, the fluidized-bed wall temperature is higher than 900 ℃, the Technology of polysilicon mainly contains following two kinds on the present treatment fluidized bed wall: the one, and ring and outer shroud in distribuor of fluidized bed air inlet port opening is divided into, outer shroud is input into not siliceous gas, is used for intercepting the deposition of silicon-containing gas on wall; The 2nd, discontinuity feeds corrosive gases or feed corrosive gases in the outer shroud pore, erodes the polysilicon that deposits on the wall.SiHCl
3There is following serious technical barrier in the hot wall type fluidized-bed.
(1) equipment materials difficulty: because the trichlorosilane temperature of reaction is between 950～1200 ℃, reactant and product contain the chlorine element, and especially by product contains a large amount of Cl
2, the HCl corrosive gases, this brings very big difficulty to equipment materials.Because it is high and characteristics such as react in acid attack gas to have temperature of reaction, metallic substance can not be used for preparation feedback equipment.The equipment of the fluidized-bed of preparation high purity polycrystalline silicon, the reaction tubes that touches with the HIGH-PURITY SILICON product particularly, be different from the material that uses in the general chemical process, should use the material of avoiding bringing contaminating impurity as far as possible, so the selection of reaction tubes material is strict.The grain silicon that touches high temperature, fluidisation that the reactor wall of the fluidized-bed of preparation polysilicon does not stop is subjected to random vibrations and serious extruding, and therefore, it is breakneck that the silicon thickness that continues to deposit at reactor wall has surpassed the value that allows.Searching not contamination particle silicon product, guarantee that the inorganic materials of when very heavy (even the silicon accumulation that deposits at the wall inwall) of strong mechanical stability is very difficult.
(2) the polysilicon deposition problem is difficult to thorough solution on the hot wall type fluidized bed body inwall: the difficulty of using the hot wall fluidized-bed reactor to prepare the grain silicon maximum is that reactant gases not only deposits on the grain silicon surface of heating, the surface of all hot solids in the fluidized-bed, all unavoidably are exposed to high-temp solid surface in the reactant gases to comprise the inwall of grain silicon surface, reactor, the inwall of inlet pipe etc., the capital deposition goes up polysilicon, and the thickness of the silicon of deposition increases in time.Though the purpose of all fluidized-beds all is depositing silicon gradually on the seed particles silicon face, but, after the polysilicon of other building block surface deposition in the reactor surpasses the thickness that allows, too much the polysilicon of deposition can destroy the mechanical stability of equipment, influence its long-term operation, even blast, consequently catastrophic, operation of equipment has to stop.
The productive rate that increases fluidized-bed is essential, and still, the continuity of fluidized-bed and the physical stability of equipment and materials should will guarantee at first that the stability of fluidized-bed also is the advantage of fluidized-bed polysilicon deposition technology.Therefore, in order to guarantee in the polysilicon deposition process, to guarantee the productive rate of fluidized-bed reactor and the mechanical stability of equipment, need effectively to improve the sedimentation effect of silicon on the reactor endoparticle silicon face, thoroughly eliminate the lip-deep deposit spathic silicon of other high-temp solid in the bed body.
(3) energy loss is bigger, product silicon productive rate is low: remove the polysilicon that deposits on the reactor wall with chemical corrosion or etching, the grain silicon product of a large amount of fluidisations also can be reacted away simultaneously in the reactor, and the silicon of optionally removing deposition almost is impossible.Therefore, common way is: stop deposit spathic silicon, use H
2, N
2, Ar, He cooling reactor inside, discharge cooled grain silicon product, the reactor of dismantling, more renewing, the refitting reactor, the refitting silica flour fully heats silica flour, imports reactant gases again, prepares grain silicon again.So the silicon that deposits on the etching reactor inwall need be with a large amount of etchant gases, gas can be taken away the heat of reaction; Dismounting and refitting fluidized-bed reactor process are necessary, the reaction needed interruption is carried out, stable control temperature of reaction needs bigger energy consumption, and be the outer wall type of heating, heating rate is slow, efficient is low, deposit spathic silicon still on the wall, and for example patent US2010/0044342A1 and patent US2011/0158857A1 are described.
(4) product particle silicon is contaminated easily.Because the silicon layer of deposition and the different thermal expansivity of reactor wall, reactor is easy to break in process of cooling, and the result is, the silicon grain that is retained in inside reactor is contaminated, and the fragment of reaction tubes makes refitting process difficulty.Because the silicon of accumulating on the reaction tube has reduced the productive rate of fluidized-bed reactor, increased the cost of product.
For addressing the above problem, developed at present and used cold wall fluidized-bed reactor to prepare the granular polycrystalline silicon of diameter 0.5～3mm.In high temperature fluidized bed body, adopt built-in well heater, add the silica flour in the hott bed body, Jia Re silicon-containing gas makes it at built-in heating rod and high temperature silica flour surface deposition silicon simultaneously.SiHCl
3Temperature of reaction is at 900～1100 ℃, and pressure is 0.3～0.5MPa.Because silica flour has higher specific surface area, fluidized-bed reactor is higher 2～3 times than bell-jar reactor productive rate, energy consumption low 1/2～1/3.Because heating rod and be highest temperature district on every side, the fluidized-bed wall temperature is cold zone, and, the fluidized-bed wall jacketed type type of cooling, be that the control of fluidized-bed wall temperature is being lower than below the decomposition temperature of trichlorosilane, solved the technical barrier of the serious deposition of fluidized-bed wall polysilicon.SiHCl
3Cold wall fluidized-bed can substitute the reduction furnace on existing " siemens " fado crystal silicon production line, perhaps with the perfect adaptation of " siemens " method production line, both grown polycrystalline silicon rod, grown granulated polycrystalline silicon again, with the direct combination of domestic " siemens " method production line at present.The granulated polycrystalline silicon product of preparation does not need the technological processs such as fragmentation through polycrystalline silicon rod, directly carries out polycrystalline silicon ingot casting, has reduced the pollution of broken process to product.
The utility model content
The purpose of this utility model is to overcome existing weak point, provides a kind of with improved cold wall fluidized-bed, and reaching with it is equipment, with trichlorosilane (SiHCl
3) and H
2Be raw material, in cold wall fluidized-bed, the reduction reaction take place under the high-temperature pressurizing, prepare the method for high purity particulate state solar-grade polysilicon.
According to the technical solution of the utility model, a kind of cold wall fluidized-bed comprises fluidized-bed, and the fluidized-bed lower end is provided with a gas mixer, described gas mixer connects in discharge pipe, is disposed with the second raw material inlet mouth and the first raw material inlet mouth on the discharge pipe; Wherein the lower end of the first raw material inlet mouth also is provided with an outlet valve, and the below of outlet valve is outlet;
Described fluidized-bed upper end is provided with filling tube and cyclonic separator; The cyclonic separator upper end is the tail gas outlet;
Described fluidized-bed also is provided with a distribuor of fluidized bed between gas mixer, distribuor of fluidized bed is connected with internal heater by two electrodes; Described internal heater is positioned at fluidized-bed inside;
Also be coated with cooling jacket on the outer wall of described fluidized-bed.
Described distribuor of fluidized bed one end is provided with an entrance of cooling water, and the other end is provided with a cooling water outlet.
On the chuck outer wall of described cooling jacket, distribuor of fluidized bed top is provided with the import of a chuck cooling material; Also be provided with chuck cooling material outlet on the chuck outer wall of fluidized-bed top, cooling jacket.
With trichlorosilane SiHCl
3And H
2Be raw material, use above-mentioned cold wall fluidized-bed, the reduction reaction takes place under 900～1200 ℃, 0.1～0.7MPa, preparation high purity particulate state solar-grade polysilicon.
The utlity model has following advantage: the cold wall fluidized-bed that the utility model provides, in fluidized bed body internal heater, make fluidized-bed maximum temperature district at heater surfaces and on every side, bed body inner core regional temperature is higher.The fluidized-bed wall adopts the chuck type of cooling, makes that temperature is lower than the trichlorosilane decomposition temperature on its wall, solves the serious deposition problems of fluidized-bed wall polysilicon.Design fluidized-bed sparger, the high pressure heating electrode is installed on it, is adopted the jacketed type cooling, both satisfied the needs of dust fluidized in the fluidized bed body, reduce the temperature of grid distributor and high voltage electrode again, solve the distribution plate orifices deposit spathic silicon and cause a distribuor of fluidized bed hole plug difficult problem.
Based on this cold wall fluidized-bed, preparation high purity particulate state solar-grade polysilicon, its production process is simple and convenient, is suitable for suitability for industrialized production.
Description of drawings
Fig. 1 the utility model structural representation.
Description of reference numerals: 1, the first raw material inlet mouth, 2, the second raw material inlet mouth, 3, gas mixer, 4, the import of chuck cooling material, 5, cooling water outlet, 6, the chuck outer wall, 7, outer wall, 8, internal heater, 9, fluidized-bed, 10, the outlet of chuck cooling material, 11, cyclonic separator, 12, tail gas outlet, 13, filling tube, 14, cooling jacket, 15, entrance of cooling water, 16, electrode, 17, distribuor of fluidized bed, 18, outlet valve, 19, outlet.
Embodiment
As shown in Figure 1, a kind of cold wall fluidized-bed comprises fluidized-bed 9, and fluidized-bed 9 lower ends are provided with a gas mixer 3, and described gas mixer 3 connects in discharge pipe, is disposed with the second raw material inlet mouth 2 and the first raw material inlet mouth 1 on the discharge pipe; Wherein the lower end of the first raw material inlet mouth 1 also is provided with an outlet valve 18, and the below of outlet valve 18 is outlet 19;
Described fluidized-bed 9 upper ends are provided with filling tube 13 and cyclonic separator 11; Cyclonic separator 11 upper ends are tail gas outlet 12;
Described fluidized-bed 9 also is provided with a distribuor of fluidized bed 17 between gas mixer 3, distribuor of fluidized bed 17 is connected with internal heater 8 by two electrodes 16; Described internal heater 8 is positioned at fluidized-bed 9 inside;
Also be coated with cooling jacket 14 on the outer wall 7 of described fluidized-bed 9.
Described distribuor of fluidized bed 17 1 ends are provided with an entrance of cooling water 15, and the other end is provided with a cooling water outlet 5.
On the chuck outer wall 6 of described cooling jacket 14, distribuor of fluidized bed 17 tops are provided with chuck cooling material import 4; Also be provided with chuck cooling material outlet 10 on the chuck outer wall 6 of fluidized-bed 9 tops, cooling jacket 14.
Application Example
(1) purge: open high pure nitrogen, purge whole cold wall fluidised bed system by the first raw material inlet mouth 1 and the second raw material inlet mouth 2, purge 30min, after use high-purity hydrogen instead and purge whole cold wall fluidised bed system, purge 60min;
(2) startup of system: start the water coolant on the distribuor of fluidized bed 17, water coolant is entered by entrance of cooling water 15, and cooling water outlet 5 flows out; Start the thermal conductivity of cooling jacket 14, cooling material enters from chuck cooling material import 4, and chuck cooling material outlet 10 is flowed out; Start deionization water coolant on the high voltage electrode 16, water coolant is entered by entrance of cooling water 15, and cooling water outlet 5 flows out;
Start the high-voltage power supply of 25000V, puncture the internal heater 8 that arranges in the fluidized-bed 9 by electrode 16, normally conduct electricity until internal heater 8, voltage descends; (3) deposition reaction: import trichlorosilane SiHCl by the second raw material inlet mouth 2
3With high-purity H
2Mixed gas, both ratios are 1:3; The first raw material inlet mouth (1) leads to high-purity H
2Gas is regulated H
2Gas flow rate is 35L/min; And by filling tube 13 adding process H
2Gas is in the technical grade silica flour of 400 ℃ of heat-activated 90min, and feed rate is 30g/min;
Described technical grade silica flour is heated to 1050 ℃ by internal heater 8 in fluidized-bed 9 after, trichlorosilane SiHCl
3On internal heater 8 and technical grade silica flour, deposit;
(4) discharging: technical grade silica flour grain silicon of gained after particle growth falls to distribuor of fluidized bed 17 lower ends, open outlet valve 18 after, flow out cold wall fluidized-bed through outlet 19, at high-purity H
2Or high-purity N
2In tightness system, be cooled to room temperature under the protection of gas, through tightness system, enter the grain silicon stocking system and carry out Vacuum Package, namely get high product purity particulate state solar-grade polysilicon.
The purity of described high purity particulate state solar-grade polysilicon is 99.99999%.
The heater material of described internal heater 8 is hot metal, is tungsten.The inwall material of described fluidized-bed is pottery.Described cooling material is liquid coolant, is specially thermal oil.
Claims (3)
1. cold wall fluidized-bed, comprise fluidized-bed (9), fluidized-bed (9) lower end is provided with a gas mixer (3), and described gas mixer (3) connects in discharge pipe, is disposed with the second raw material inlet mouth (2) and the first raw material inlet mouth (1) on the discharge pipe; Wherein the lower end of the first raw material inlet mouth (1) also is provided with an outlet valve (18), and the below of outlet valve (18) is outlet (19);
Described fluidized-bed (9) upper end is provided with filling tube (13) and cyclonic separator (11); Cyclonic separator (11) upper end is tail gas outlet (12);
It is characterized in that: described fluidized-bed (9) also is provided with a distribuor of fluidized bed (17) between gas mixer (3), and distribuor of fluidized bed (17) is connected with internal heater (8) by two electrodes (16); Described internal heater (8) is positioned at fluidized-bed (9) inside;
Also be coated with cooling jacket (14) on the outer wall (7) of described fluidized-bed (9).
2. cold wall fluidized-bed according to claim 1, it is characterized in that: described distribuor of fluidized bed (17) one ends are provided with an entrance of cooling water (15), and the other end is provided with a cooling water outlet (5).
3. cold wall fluidized-bed according to claim 1, it is characterized in that: the chuck outer wall (6) of described cooling jacket (14) is gone up, distribuor of fluidized bed (17) top is provided with chuck cooling material import (4); Also be provided with chuck cooling material outlet (10) on the chuck outer wall (6) of fluidized-bed (9) top, cooling jacket (14).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320171511 CN203173826U (en) | 2013-04-08 | 2013-04-08 | Cold wall fluidized bed |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320171511 CN203173826U (en) | 2013-04-08 | 2013-04-08 | Cold wall fluidized bed |
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|---|---|
| CN203173826U true CN203173826U (en) | 2013-09-04 |
Family
ID=49070559
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|---|---|---|---|
| CN 201320171511 Withdrawn - After Issue CN203173826U (en) | 2013-04-08 | 2013-04-08 | Cold wall fluidized bed |
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|---|---|
| CN (1) | CN203173826U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103172067A (en) * | 2013-04-08 | 2013-06-26 | 无锡中彩科技有限公司 | Cold wall fluidized bed and application thereof |
-
2013
- 2013-04-08 CN CN 201320171511 patent/CN203173826U/en not_active Withdrawn - After Issue
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103172067A (en) * | 2013-04-08 | 2013-06-26 | 无锡中彩科技有限公司 | Cold wall fluidized bed and application thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20130904 Effective date of abandoning: 20140924 |
|
| RGAV | Abandon patent right to avoid regrant |