CN101475175A - Method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride - Google Patents
Method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride Download PDFInfo
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- CN101475175A CN101475175A CNA2009100582548A CN200910058254A CN101475175A CN 101475175 A CN101475175 A CN 101475175A CN A2009100582548 A CNA2009100582548 A CN A2009100582548A CN 200910058254 A CN200910058254 A CN 200910058254A CN 101475175 A CN101475175 A CN 101475175A
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Abstract
The invention discloses a method for producing trichlorosilane from silicon tetrachloride through plasma hydrogenation. The method is characterized in that through induction of a high-frequency coil, hydrogenous plasma is produced to treat a gaseous silicon tetrachloride raw material added to a plasma region; two raw materials participate in reaction in a plasma state; and the silicon tetrachloride is hydrogenated into the trichlorosilane. In a high-frequency coil inducted plasma rector, a gas circuit is divided into three circuits of axis central gas, central main gas and protective gas; hydrogenous gas is subjected to plasma arc starting to form a hydrogenous plasma flame region; the gasified silicon tetrachloride is added through an axis center, reacts in the hydrogenous plasma flame region, and is converted into the trichlorosilane; after the reaction, mixed gas is subjected to heat exchange, condensation, cooling and distillation procedures to obtain a trichlorosilane liquid, a silicon tetrachloride liquid, chlorine hydride, hydrogen gas and argon gas respectively, wherein the silicon tetrachloride, circulating hydrogen gas and the argon gas are in the reactor; and the trichlorosilane and the chlorine hydride enter the polysilicon production procedure. The method can concisely treat the silicon tetrachloride as a byproduct of polysilicon with high efficiency and environmental protection, simultaneously obtains raw materials needed by the polysilicon, and greatly reduces the output of waste and production cost for the polysilicon.
Description
Technical field
The invention belongs to hydrogenation and round-robin chemical enginnering process, particularly a kind of method that adopts radio-frequency induction plasma hydrogenization processing silicon chloride to silicon tetrachloride as by-product of polysilicon.
Background technology
In recent years, along with the fast development of photovoltaic industry, greatly stimulated demand to solar cell raw material polysilicon.The polycrystalline silicon raw material supply is the restriction bottleneck of current photovoltaic industry.The photovoltaic generation cost buildup analysis is known the photovoltaic cell cost is over half at present is the polysilicon cost, so by technical renovation, reducing the production of polysilicon cost is the inevitable prerequisite that the whole from now on photovoltaic generation whole world is popularized.
According to statistics, during present global polysilicon is made, production of polysilicon above 70% is to adopt siemens (Siemens) technology (to see B.Ceccaroli etc.Handbook of Photovoltaic Science and Engineering for details, Wiley, New Jersey, 2003, p.156.) obtain, Siemens process unavoidably will produce a large amount of silicon tetrachloride by products at polysilicon production process, under the state-of-the art, silicon tetrachloride in the product/polysilicon output ratio is greater than 10.And silicon tetrachloride is a kind of strong toxicity, and the chemical substance that can not directly drain and bury can only could solve environmental issue by after the chemical conversion.In the actual production at present, the general mode that is hydrogenated to trichlorosilane or the white carbon black of preparation gas phase that adopts is handled (seeing CN1850599A for details).And the industrialization hydrogenation process generally is divided into two kinds of methods at present:
(1) adopt the process furnace hydrogenation process that silicon tetrachloride is converted into trichlorosilane, concrete reactional equation is as follows:
Though calculate at the 1300K free energy of reaction just for negative by thermodynamic argument, yet industrial reaction actuator temperature working temperature generally is selected in 1500K～1800K interval, and conversion reaction transformation efficiency low (transformation efficiency is less than 20%), in addition, this method converting apparatus investment is big, the energy consumption height, low in economic efficiency.
(2) mode of employing silicon fluidized-bed, its chemical reaction equation is as follows:
(2)
This method shortcoming is: reaction conditions High Temperature High Pressure, reactor made are taken expensive, and the equipment corrosion problem causes this technology industrial applications not as the wide model of process furnace hydrogenation mode.
For overcoming the shortcoming of above-mentioned two class methods, Chinese patent literature discloses the hydrogen plasma in September, 2008 and has transformed the method (publication number CN 101254921A) that silicon tetrachloride prepares trichlorosilane.This method is made thermal plasma with hydrogen earlier and is become gas, with silicon tetrachloride gas mixing soaking, sends into reactor reaction then again, generates trichlorosilane.With respect to above-mentioned two class methods, the plasma hydrogenization method since have high temperature, at a high speed, advantage that transformation efficiency is high, receive much concern.
But this method also has some shortcomings, mainly is:
1. this method adopts the direct current-arc plasma treatment technology, because direct current-arc plasma is unavoidably introduced the pollution of electrode metal to reaction mass at high temperature, strong current discharge process, strengthen the distillation purification process burden of back trichlorosilane purifying, increase the production of polysilicon cost indirectly.And the plasma flame of direct current arc is short, short, poor temperature uniformity of temperature field lack of homogeneity, the reactant residence time in plasma flame, and transformation efficiency is lower and unstable.
2. plasma conversion silicon tetrachloride prepares trichlorosilane, it is the high-temperature chemical reaction process, speed of response is exceedingly fast, with millisecond meter (unstripped gas in reactor the residence time＜50ms), can be considered thermodynamic process in theory, when the big flow unstripped gas of industrially scalable enters reaction, there is following difficulty:
After unstripped gas enters reactor, can not be fast with become the gas soaking, directly have influence on the reaction effect of unstripped gas, transformation efficiency is low, product yield is low.
At above-mentioned difficulties, this method adopts symmetrical in opposite directions air inlet method, is about to silicon tetrachloride gas and supplies gas with annular diffuser, forms silicon tetrachloride circulation, and hydrogen plasma stream runs through this circulation, and the two mixes soaking, to reach the purpose of quick soaking.However, it is still limited that unstripped gas mixes equal thermal velocity.
3. this method is from preparing the hydrogen plasma to generating trichlorosilane, total three process, promptly earlier hydrogen is made thermal plasma and become gas, again with silicon tetrachloride gas mixing soaking, send into reactor reaction then and generate trichlorosilane, technical process is long, satisfy the requirement of reaction times Millisecond, difficulty is very big, and the industrially scalable Development Prospect is little.
Summary of the invention
Purpose of the present invention, be to overcome above-mentioned hydrogen plasma to transform the shortcoming that silicon tetrachloride prepares the trichlorosilane method, a kind of method of preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride is provided, and the technical process of present method is succinct, and the plasma of unstripped gas, one step of reaction generation trichlorosilane finish; Present method does not have the pollution of electrode metal to reaction mass, can save follow-up removal of impurities operation, reduces the production of polysilicon cost; The device that present method is used, ability is changeable, and is unrestricted.
The technique means that realizes above-mentioned purpose is:
A kind of plasma hydrogenation of silicon tetrachloride prepares the method for trichlorosilane, hydrogen, silicon tetrachloride pneumatic transmission are gone into to be ionized in the electric field hydrogen plasma (orifice) gas, silicon tetrachloride plasma (orifice) gas, two kinds of plasma (orifice) gass react immediately, generation contains the gas mixture of trichlorosilane, isolates trichlorosilane in this gas mixture with conventional separation method again.
Described electric field is an alternating electric field.
Described alternating electric field is the radio-frequency induction electric field.
The method that described hydrogen, silicon tetrachloride pneumatic transmission are gone in the electric field adopts concentric axial flow inhalation conduction method, and central shaft gas is silicon tetrachloride gas, and peripheral ring gas is hydrogen, or central shaft gas is hydrogen, and peripheral ring gas is silicon tetrachloride gas.
The periphery of described peripheral ring gas also has guard ring gas, and this guard ring gas is a kind of or hydrogen-argon-mixed of argon gas, hydrogen.
The concrete steps of present method are as follows:
The concrete steps of this method are:
1) plasma reactor is set, feeds the striking gas electric arc that ignites, feed raw hydrogen again, produce hydrogeneous isoionic flame zone;
2) feed protection gas argon gas, shielding reactor wall;
3) feed the silicon tetrachloride unstripped gas to hydrogen plasma flame district, be ionized into the silicon tetrachloride plasma, in the plasma flame district, silicon tetrachloride plasma and hydrogen plasma react, and generate the gas mixture that contains trichlorosilane;
4) isolate trichlorosilane in this gas mixture with conventional separation method.
Described striking gas is argon gas or argon hydrogen gas mixture.
Hydrogen plasma than Chinese patent literature CN101254921A transforms the method that silicon tetrachloride prepares trichlorosilane, the invention has the advantages that:
1) owing to adopts the radio-frequency induction electric field to prepare plasma, there is not electrode corrosion, not having new pollutent produces, and it is little to increase the pollutent probability in the middle of the technological process, if raw material silicon tetrachloride purity height, the product trichlorosilane can not carry out or only handle a little just can entering production of polysilicon, greatly reduces the production of polysilicon cost, corresponding raising polysilicon output.
2) owing to adopt the radio-frequency induction electric field to prepare plasma, plasma flame is longer, the temperature field good uniformity, and reactive behavior is big, and hydrogen plasma, the residence time of silicon tetrachloride plasma in this flame are longer, sufficient reacting, a transformation efficiency is up to 52%.
3) because hydrogen and silicon tetrachloride are all added from the upstream of plasma flame, hydrogen and silicon tetrachloride all are to enter reaction with the high-temperature plasma attitude, need not soaking, unstripped gas mixing soakage device needn't be set; Unstripped gas directly in the reaction of plasma flame district, also needn't be provided with special reactor.Raw material plasma and reaction are almost carried out simultaneously, and a step finishes, and flow process is very succinct, and speed of response satisfies the requirement in reaction times fully.
4) because need not unstripped gas mixing soaking, the ability of production equipment is unrestricted, and be changeable, has the industrially scalable development prospect.
Description of drawings
Fig. 1 is apparatus structure of the present invention and process flow sheet.
Fig. 2 is a high-frequency induction plasma reactor structural representation of the present invention.
Code name implication among the figure: 1 power-supply controller of electric, 2 high-frequency induction plasma reactor, 3 snubbers, 4 heat exchangers; 5 compressors, 6 water coolers, 7 gas-liquid separators; 8 gas delivery towers, 9 distillation towers, 10 hydrogenchloride output channels; 11 trichlorosilane output channels, 12 silicon tetrachloride feedback line, 13 argon hydrogen feedback line; 14 protection argon gas intake pipelines, 15 induction copper coils, 16 plasma flames; 17 outer ring channels, 18 central shaft gas passages, 19 interior ring passages.
Embodiment
Further specify the present invention below in conjunction with accompanying drawing.
Referring to Fig. 1: the inventive system comprises plasma reactor 2, this plasma reactor 2 has power-supply controller of electric 1, the downstream of plasma reactor 2 has snubber 3, heat exchanger 4, compressor 5, water cooler 6, the gas-liquid separator 7 that is disposed in order, the gas phase media outlet of gas-liquid separator 7 connects gas delivery tower 8, and the liquid phase medium outlet connects distillation tower 9.
One of characteristics of the present invention are that plasma reactor 2 adopts high-frequency induction plasma reactor, frequency 5MHz.Have following two advantages:
1. the electric field of this reactor generation is an alternating electric field, does not have fixed electorde, thereby does not have the electrode metal corrosion, can contaminated feedstock.
2. compare with the direct current plasma producer, plasma flame is longer, the temperature field good uniformity, and reactive behavior is big, and hydrogen plasma, the residence time of silicon tetrachloride plasma in this flame are longer, sufficient reacting, thereby transformation efficiency is very high.
Two of characteristics of the present invention are that the raw material air inlet of plasma reactor 2 adopts concentric shafts to flow to the gas mode.
Referring to Fig. 2: after coil 15 energisings of plasma reactor 2, the zone of corresponding coil 15 forms alternating electric field, in this alternating electric field; medium is ionized, and forms plasma flame 16, in the upstream of plasma flame 16; be provided with three induction trunks; be central shaft gas passage 18, be used to feed silicon tetrachloride gas, interior ring passage 19; be used to feed hydrogen; outer ring channel 17 is used for feeding protection gas (argon hydrogen gas mixture), constitutes concentric shafts and flows to depressed structure.Hydrogen and silicon tetrachloride gas all add from the upstream of plasma flame, all are to enter reaction with the high-temperature plasma attitude, and the plasma of unstripped gas and reaction are almost carried out simultaneously, and a step finishes, and flow process is very succinct.
Also but central shaft gas passage 18 feeds hydrogen, and interior ring passage 19 feeds silicon tetrachloride gas.
Workflow of the present invention is as follows:
1) after employing argon gas or argon hydrogen gas mixture feed 2 strikings of high-frequency induction reactor, feeds raw hydrogen, produce hydrogeneous isoionic flame zone 16 from central shaft gas passage 18;
2) the shielding gas argon gas is fed outer ring channel 17, the shielding reactor wall;
3) the silicon tetrachloride unstripped gas is added from central shaft gas passage 18, gas pressure intensity 1atm, the power of adjusting radio-frequency power supply 1 makes plasma flame stable, flame temperature 〉=2000K, in the plasma flame district, silicon tetrachloride is ionized to plasma, and reacts with the hydrogen plasma, generation contains the gas mixture of trichlorosilane, the component of this gas mixture is: trichlorosilane and hydrogenchloride that reaction generates, still unreacted silicon tetrachloride, hydrogen, and the argon gas of not participating in reaction;
4) reacted gas mixture is introduced into snubber 3 expansion coolings, enters heat exchanger 4 heat exchange cooling again;
5) gas after the heat exchange enters compressor 5 compressions, and wherein trichlorosilane, silicon tetrachloride are compressed to liquid state, form the gas-liquid mixed phase fluid;
6) the gas-liquid mixed phase fluid is entered gas-liquid separator 7, carry out gas-liquid separation;
7) liquid portion enters distillation tower 9 rectifying, obtains trichlorosilane and silicon tetrachloride respectively, and trichlorosilane enters the production of polysilicon operation through export pipeline (road) 11, and silicon tetrachloride feeds back to reactor 2 recycles through pipeline 12; Gas partly separates by gas delivery tower 8, obtains hydrogenchloride and argon hydrogen gas mixture respectively, and hydrogenchloride enters the production of polysilicon operation through export pipeline (road) 10, and argon hydrogen gas mixture feeds back to reactor 2 recycles through pipeline 13.
In the present invention, under the situation of not considering electrode corrosion, also can use the DC electric field plasma reactor, but the unstripped gas air inlet must adopt concentric shafts to flow to the gas mode, from the upstream feeding of plasma zone.
Claims (7)
1. the method for a preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride, hydrogen, silicon tetrachloride pneumatic transmission are gone into to be ionized in the electric field hydrogen plasma (orifice) gas, silicon tetrachloride plasma (orifice) gas, two kinds of plasma (orifice) gass react immediately, generation contains the gas mixture of trichlorosilane, isolates trichlorosilane in this gas mixture with conventional separation method again.
2. the method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride according to claim 1, it is characterized in that: described electric field is an alternating electric field.
3. the method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride according to claim 2, it is characterized in that: described alternating electric field is the radio-frequency induction electric field.
4. the method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride according to claim 1, it is characterized in that: the method that described hydrogen, silicon tetrachloride pneumatic transmission are gone in the electric field adopts concentric axial flow inhalation conduction method, central shaft gas is silicon tetrachloride gas, peripheral ring gas is hydrogen, or central shaft gas is hydrogen, and peripheral ring gas is silicon tetrachloride gas.
5. the method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride according to claim 4 is characterized in that: the periphery of described peripheral ring gas, also have guard ring gas, and this guard ring gas is a kind of or hydrogen-argon-mixed of argon gas, hydrogen.
6. the method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride according to claim 1 is characterized in that the concrete steps of this method are:
1) plasma reactor is set, feeds the striking gas electric arc that ignites, feed raw hydrogen again, produce hydrogeneous isoionic flame zone;
2) feed protection gas, the shielding reactor wall;
3) feed the silicon tetrachloride unstripped gas to hydrogen plasma flame district, make it become plasma state, in the plasma flame district, plasma state silicon tetrachloride and hydrogen react, and generate the gas mixture that contains trichlorosilane;
4) isolate trichlorosilane in this gas mixture with conventional separation method.
7. the method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride according to claim 6, it is characterized in that: described striking gas is argon gas or argon hydrogen gas mixture.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009100582548A CN101475175B (en) | 2009-01-21 | 2009-01-21 | Method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride |
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| CN2009100582548A CN101475175B (en) | 2009-01-21 | 2009-01-21 | Method for preparing trichlorosilane by plasma hydrogenization of silicon tetrachloride |
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| CN101475175B CN101475175B (en) | 2011-05-04 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102039082A (en) * | 2010-06-09 | 2011-05-04 | 特变电工新疆硅业有限公司 | Method and device for vaporizing hydrogen chloride in tail gas in polycrystalline silicon production |
| AT508883B1 (en) * | 2009-10-14 | 2011-07-15 | Inocon Technologie Gmbh | HEATING DEVICE FOR POLYSILICIUM REACTORS |
| CN101734666B (en) * | 2009-11-24 | 2012-09-26 | 中国科学院过程工程研究所 | Method for preparing trichlorosilane and dichlorosilane by hydrogenating silicon tetrachloride through microwave plasma |
| CN103787338A (en) * | 2012-10-29 | 2014-05-14 | 王红卫 | Trichlorosilane plasma preparation method and preparation apparatus thereof |
| CN103787337A (en) * | 2012-10-29 | 2014-05-14 | 王红卫 | Plasma preparation apparatus of trichlorosilane |
| CN104261413A (en) * | 2014-09-19 | 2015-01-07 | 天津大学 | Method and device for producing trichlorosilane through reducing silicon tetrachloride by using low-temperature plasmas |
Families Citing this family (1)
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| AT513735B1 (en) * | 2012-11-27 | 2015-02-15 | Activ Solar Gmbh | Process for the plasma-chemical production of chlorosilanes |
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2009
- 2009-01-21 CN CN2009100582548A patent/CN101475175B/en active Active
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT508883B1 (en) * | 2009-10-14 | 2011-07-15 | Inocon Technologie Gmbh | HEATING DEVICE FOR POLYSILICIUM REACTORS |
| CN101734666B (en) * | 2009-11-24 | 2012-09-26 | 中国科学院过程工程研究所 | Method for preparing trichlorosilane and dichlorosilane by hydrogenating silicon tetrachloride through microwave plasma |
| CN102039082A (en) * | 2010-06-09 | 2011-05-04 | 特变电工新疆硅业有限公司 | Method and device for vaporizing hydrogen chloride in tail gas in polycrystalline silicon production |
| CN102039082B (en) * | 2010-06-09 | 2011-08-31 | 特变电工新疆硅业有限公司 | Method and device for vaporizing hydrogen chloride in tail gas in polycrystalline silicon production |
| CN103787338A (en) * | 2012-10-29 | 2014-05-14 | 王红卫 | Trichlorosilane plasma preparation method and preparation apparatus thereof |
| CN103787337A (en) * | 2012-10-29 | 2014-05-14 | 王红卫 | Plasma preparation apparatus of trichlorosilane |
| CN104261413A (en) * | 2014-09-19 | 2015-01-07 | 天津大学 | Method and device for producing trichlorosilane through reducing silicon tetrachloride by using low-temperature plasmas |
| CN104261413B (en) * | 2014-09-19 | 2016-03-23 | 天津大学 | Plasma deoxidization in low termprature producing trichlorosilane by using silicon tetrachloride method and device thereof |
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