CN101376078B - Method for recovering and processing tail gas produced from production of polycrystalline silicon - Google Patents
Method for recovering and processing tail gas produced from production of polycrystalline silicon Download PDFInfo
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- CN101376078B CN101376078B CN2007101210581A CN200710121058A CN101376078B CN 101376078 B CN101376078 B CN 101376078B CN 2007101210581 A CN2007101210581 A CN 2007101210581A CN 200710121058 A CN200710121058 A CN 200710121058A CN 101376078 B CN101376078 B CN 101376078B
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Abstract
The invention discloses a recycling method for tail gas from polysilicon production. The tail gas comprises hydrogen, hydrogen chloride and dichlorosilane. The method comprises the following steps: introducing the tail gas into liquid silicon tetrachloride to facilitate the dissolution of hydrogen chloride and dichlorosilane in liquid silicon tetrachloride, so as to separate hydrogen from hydrogen chloride and dichlorosilane, and reclaim hydrogen; heating up or pressurizing silicon tetrachloride which has dissolved hydrogen chloride and dichlorosilane, so as to desorb hydrogen chloride and dichlorosilane from liquid silicon tetrachloride; and ensuring that dichlorosilane is in liquid state and hydrogen chloride in gas state through controlling the temperature or pressure of desorbed hydrogen chloride and dichlorosilane, so that hydrogen chloride and dichlorosilane can be separated and recycled. The invention adopts silicon tetrachloride dry method to process and recycle the tail gas, so as that the tail gas can be recycled in polysilicon production. Therefore, the method has the advantages of fully using the raw material, reducing pollutants, achieving environmental friendliness and reducing the cost.
Description
Technical field
The present invention relates to a kind of recycling industrial and produce the method for the tail gas that polysilicon produced, more specifically, relate to a kind of method of utilizing the silicon tetrachloride recycling to produce the tail gas that polysilicon produced.
Background technology
Polysilicon is the raw material of preparation monocrystalline silicon, finally is used to produce integrated circuit and electronic device, and be one of the highest basic material of information industry consumption maximum, purity requirement, also be the product and the industry of state key encourage growth.
World advanced person's production of polysilicon technology by the company monopolizing of beautiful, day, moral three states always, all there be know-how and technical characterstic separately in each company, through constantly research, exploitation, formed production technology separately, and from national strategy angle separately, strict control technology transfer also monopolizes global polysilicon market.
China's polysilicon industry is started in the fifties, middle nineteen sixties is realized industrialization, early seventies is pell-mell development once, factory is family surplus in the of 20 nearly, and what all adopt is traditional Siemens process, backward in technique, environmental pollution is serious, supplies consumption is big, production cost height, most losses of enterprise and stop production in succession or change the line of production.
The outstanding characteristics of tradition production of polysilicon technology are " tail gas hydrometallurgic recovery " technology, and promptly the tail gas that produces in the polysilicon production process is used water wash, recover hydrogen after preliminary pressurization separates chlorosilane.Yet in the water wash process, foreign gases such as the oxygen in the water, carbon dioxide can be polluted hydrogen, so a large amount of hydrogen that reclaims needs to purify once more.
In addition, chlorosilane hydrolysis in the lessivation produces sewage, needs further to handle, and causes environmental pollution and supplies consumption big.Simultaneously, the hydrogen of generation also fails to be fully utilized, and has both wasted the energy, has increased cost, has caused environmental pollution again.
Summary of the invention
Purpose of the present invention is intended to overcome at least one shortcoming of the prior art, a kind of method of utilizing the silicon tetrachloride recycling to produce the tail gas that polysilicon produced is proposed, the method according to this invention is utilized dry back ending gas, therefore also can be called " tail gas dry process recovery " technology.
Utilize method of the present invention, not only can reclaim fully with recycling, and can significantly reduce the generation of pollutant in the production, made full use of material simultaneously, reduced cost tail gas.
For achieving the above object, embodiments of the invention propose a kind of method of producing the tail gas that polysilicon produced that recycles, and described tail gas mainly comprises hydrogen (H
2), hydrogen chloride (HCl) and dichloro-dihydro silicon (SiH
2Cl
2), said method comprising the steps of: make described tail gas by liquid silicon tetrachloride, so that hydrogen chloride and dichloro-dihydro silicon are dissolved in the liquid silicon tetrachloride, thereby hydrogen is separated with dichloro-dihydro silicon with hydrogen chloride, thus recover hydrogen; The silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is heated up and/or pressurizes, hydrogen chloride and dichloro-dihydro silicon are desorbed from liquid silicon tetrachloride; With the pressure and/or the temperature of the hydrogen chloride and the dichloro-dihydro silicon of the gaseous state that desorbs by control, make dichloro-dihydro silicon become liquid state and hydrogen chloride remains gaseous state, thereby separate and reclaim hydrogen chloride and dichloro-dihydro silicon respectively.
Further embodiment further comprises according to the present invention: with hydrogen chloride and dichloro-dihydro silicon desorb the silicon tetrachloride circulation be used to reclaim tail gas.
The further embodiment according to the present invention, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is raised to 70～220 ℃.
More specifically, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is warmed up to 70～220 ℃ by classification.
The further embodiment according to the present invention, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is pressurized to 0.1～2.0Mpa.
Particularly, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is pressurized to 0.1～2.0Mpa by classification.
The further embodiment according to the present invention, the temperature of the hydrogen chloride of the gaseous state that desorbs and dichloro-dihydro silicon is controlled as 30～-70 ℃.
The temperature of the hydrogen chloride of the gaseous state that desorbs particularly, and dichloro-dihydro silicon is 30～-70 ℃ by grading control.
The further embodiment according to the present invention, the pressure of the hydrogen chloride of the gaseous state that desorbs and dichloro-dihydro silicon is controlled as 0.1～2.0Mpa.
The pressure of the hydrogen chloride of the gaseous state that more specifically, desorbs and dichloro-dihydro silicon is 0.1～2.0Mpa by grading control.
According to the present invention, owing to adopt the tail gas that produces in the dry process production of polysilicon, therefore, overcome and eliminated the shortcoming of conventional wet recovery technology, tail gas has obtained sufficient recycling simultaneously, especially the tail gas that reclaims is turned back in the production of polysilicon operation, make the means of production can be able to sufficient utilization, and significantly reduced the generation and the quantity of pollutant in the production.
According to the present invention, material is in closed cycle is used, greatly reduce the consumption of raw and auxiliary material, fundamentally solved the problem of environmental pollution that production of polysilicon causes, simultaneously, save project investment, improved product quality and output, reduce cost, made the construction and upgrading of production of polysilicon project obtain sufficient initiative.
According to the present invention, silicon tetrachloride can be recycling, so cost is low, and the efficient height is simple to operate.
The feature and advantage that the present invention adds part in the following description provide, and part will become obviously from the following description, or recognize by practice of the present invention.
Description of drawings
Fig. 1 is the industrial production schematic flow sheet of polysilicon;
Fig. 2 produces the schematic flow sheet of the method for the tail gas that polysilicon produced for the silicon tetrachloride recycling that utilizes according to the embodiment of the invention.
The specific embodiment
So that explain the present invention, described embodiment is exemplary, and can not be interpreted as limitation of the present invention below by describing specific embodiment with reference to the accompanying drawings.
With reference to figure 1, wherein show and to use the FB(flow block) of industrial production polysilicon of producing the method for the tail gas that polysilicon produced according to the recycling of the embodiment of the invention, use production of polysilicon technology of the present invention, be that to utilize industrial silicon and hydrogen chloride (HCl) be primary raw material, generate with trichlorosilane (SiHCl by the control reaction condition
3) be the main chlorosilane and the mixture of hydrogen, then by purification technique to trichlorosilane (SiHCl
3) purify after, send into reduction furnace, make trichlorosilane (SiHCl
3) and auxiliary material hydrogen (H
2) reaction, reduction generates polysilicon.
In the process of above-mentioned industrial production polysilicon, the tail gas of generation mainly comprises hydrogen (H
2), hydrogen chloride (HCl) and chlorosilane, described chlorosilane mainly comprises dichloro-dihydro silicon (SiH
2Cl
2).In addition, chlorosilane also contains trichlorosilane (SiHCl
3) and silicon tetrachloride (SiCl
4).
Reaction main in the production process is:
Si+HCl→SiHCl
3+SiCl
4+H
2
SiHCl
3→Si+SiCl
4+H
2
SiHCl
3+H
2→Si+HCl
Need to prove, according to the present invention, utilize the tail gas of silicon tetrachloride recycling mainly to comprise hydrogen, hydrogen chloride and dichloro-dihydro silicon, as for trichlorosilane that wherein contains and silicon tetrachloride, can separate in advance, for example, utilize hydrogen, hydrogen chloride and dichloro-dihydro silicon different with the boiling point of trichlorosilane and silicon tetrachloride, by control temperature and/or pressure, just can separate trichlorosilane and silicon tetrachloride in the tail gas through gas-liquid separation, this is readily appreciated that for a person skilled in the art, repeats no more here.
The present invention relates generally to and utilizes the silicon tetrachloride recovery and handle main component is the tail gas of hydrogen, hydrogen chloride and dichloro-dihydro silicon.
The method of producing the tail gas that polysilicon produced according to the recycling of the embodiment of the invention is described below with reference to Fig. 2.
The tail gas that produces in the polysilicon production process is collected, and described tail gas mainly comprises hydrogen, hydrogen chloride and dichloro-dihydro silicon.As mentioned above, as for trichlorosilane in the tail gas and silicon tetrachloride, can separate in advance, this is not the emphasis that the present invention discussed, and therefore omits detailed description.
Utilize liquid silicon tetrachloride (SiCl
4) as absorbent, make the hydrogen chloride (HCl) and the dichloro-dihydro silicon (SiH of gaseous state
2Cl
2) be dissolved in the silicon tetrachloride, so that with the hydrogen (H of gaseous state
2) and hydrogen chloride (HCl) and dichloro-dihydro silicon (SiH
2Cl
2) separate.
Separated hydrogen can be returned the production that is used for polysilicon, and for example separated hydrogen can generate polysilicon with the trichlorosilane reaction after purifying.Thus, made full use of the hydrogen in the tail gas, reduced the consumption of material, reduced cost, and reduced pollution.
Then, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is heated up and/or pressurizes, hydrogen chloride and dichloro-dihydro silicon are desorbed from the silicon tetrachloride of liquid state.For example, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is raised to 70～220 ℃ and/or be pressurized to 0.1～2.0Mpa, yet, above-mentioned process conditions only are exemplary, as long as utilize hydrogen chloride different with the boiling point of silicon tetrachloride with dichloro-dihydro silicon, by gas-liquid separation hydrogen chloride is separated with silicon tetrachloride with dichloro-dihydro silicon, any process conditions can be used.
More specifically, the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon heats up and/or pressurizes is that classification is carried out, that is to say, for example, the temperature of having dissolved the silicon tetrachloride of hydrogen chloride and dichloro-dihydro silicon is not to be heated to 70～220 ℃ quickly, but being heated to 70～220 ℃ step by step, the classification heating can be undertaken by the heat exchange of classification.In like manner, the pressure that has dissolved the silicon tetrachloride of hydrogen chloride and dichloro-dihydro silicon also can classification be pressurized to 0.1～2.0Mpa.
Then, the hydrogen chloride of the gaseous state that desorbs by control and the pressure of dichloro-dihydro silicon and/or temperature make dichloro-dihydro silicon become liquid state and hydrogen chloride remains gaseous state, thereby separate and reclaim hydrogen chloride and dichloro-dihydro silicon respectively.For example, the pressure of the hydrogen chloride of the gaseous state that desorbs and dichloro-dihydro silicon is controlled as 0.1～2.0Mpa, and temperature is controlled as 30～-70 ℃.Yet, as long as utilize hydrogen chloride different, hydrogen chloride is separated with dichloro-dihydro silicon by gas-liquid separation with the boiling point of dichloro-dihydro silicon, can use any suitable temperature and/or pressure process condition.
Hydrogen chloride and dichloro-dihydro silicon can circulate from the silicon tetrachloride that wherein desorbs and be used to reclaim tail gas, promptly, circulation is used to dissolve the tail gas that mainly comprises hydrogen, hydrogen chloride and dichloro-dihydro silicon, thereby silicon tetrachloride can recycle, and has reduced consumption of raw materials.
And then, the pressure of the hydrogen chloride of the gaseous state that desorbs and dichloro-dihydro silicon and/or temperature controlling also can be that classification is carried out, the pressure of the hydrogen chloride of the gaseous state that for example, desorbs and dichloro-dihydro silicon and/or temperature are controlled to be 0.1～2.0Mpa and 30～-70 ℃ respectively step by step.
According to embodiments of the invention, because the hydrogen chloride of the gaseous state that from silicon tetrachloride, desorbs and dichloro-dihydro silicon temperature is higher, pressure can be constant substantially, therefore particularly be that the hydrogen chloride of the gaseous state that will desorb and the temperature of dichloro-dihydro silicon are reduced to for example 30～-70 ℃, cooling can be undertaken by heat exchange step by step, the heat that exchanges can be used for the silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is heated up, thereby heat can recycle in system, reduce energy resource consumption, reduce cost.Yet the present invention is not limited to above-mentioned concrete pressure and temperature condition.
As mentioned above, the hydrogen of separating can turn back in the polysilicon production process, react with trichlorosilane, produce polysilicon, thereby the hydrogen in the tail gas can be recycling in polysilicon production process, isolated hydrogen chloride can be used in the industrial silicon reaction and generates trichlorosilane, thereby is used for the production of polysilicon.
Thus, method according to recycling tail gas of the present invention, can effectively utilize dry method and reclaim and utilize producing various compositions in the tail gas that polysilicon produced, thereby improved the organic efficiency of tail gas, and can not produce pollution, improve utilization ratio of raw materials, reduced cost and energy resource consumption.
Following table shows the method according to this invention and conventional wet side compares the effect that hydrogen reclaims.
The present invention is to the comparison to the tail gas recycle effect of tail gas recycle effect and conventional art
| Project | The present invention | Conventional wet |
| Tail gas recycle rate % | 99.99％ | 70～85％ |
| Tail gas recycle purity | More than 99.99% | 95～99％ |
As can be seen, utilize method of the present invention from above-mentioned table, the rate of recovery of tail gas and recovery quality all are much higher than traditional wet method, according to dry method of the present invention, tail gas almost completely obtains reclaiming and utilizing, and has reduced consumption of raw materials, save cost, reduced pollution.
Although foregoing has illustrated and has described embodiments of the invention, but for those skilled in the art in this area, without departing from the principles and spirit of the present invention, can change these embodiment, so scope of the present invention is limited by claims and equivalent processes thereof.
Claims (6)
1. one kind recycles the method for producing the tail gas that polysilicon produced, and described tail gas mainly comprises hydrogen, hydrogen chloride and dichloro-dihydro silicon, said method comprising the steps of:
Make described tail gas by liquid silicon tetrachloride, so that hydrogen chloride and dichloro-dihydro silicon are dissolved in the liquid silicon tetrachloride, thereby hydrogen is separated with dichloro-dihydro silicon with hydrogen chloride, thus recover hydrogen;
The silicon tetrachloride that has dissolved hydrogen chloride and dichloro-dihydro silicon is warmed up to 70～220 ℃, hydrogen chloride and dichloro-dihydro silicon are desorbed from liquid silicon tetrachloride; With
The hydrogen chloride of the gaseous state that desorbs by control and the pressure and/or the temperature of dichloro-dihydro silicon make dichloro-dihydro silicon become liquid state and hydrogen chloride remains gaseous state, thereby separate and reclaim hydrogen chloride and dichloro-dihydro silicon respectively.
2. the method for the tail gas that polysilicon produced is produced in recycling according to claim 1, further comprises: the silicon tetrachloride circulation that hydrogen chloride and dichloro-dihydro silicon are desorbed is used to reclaim tail gas.
3. the method for the tail gas that polysilicon produced is produced in recycling according to claim 1, and the silicon tetrachloride that has wherein dissolved hydrogen chloride and dichloro-dihydro silicon is warmed up to 70～220 ℃ by classification.
4. the method for the tail gas that polysilicon produced is produced in recycling according to claim 1, and the temperature of the hydrogen chloride of the gaseous state that wherein desorbs and dichloro-dihydro silicon is controlled as 30～-70 ℃.
5. the method for the tail gas that polysilicon produced is produced in recycling according to claim 4, and the temperature of the hydrogen chloride of the gaseous state that wherein desorbs and dichloro-dihydro silicon is 30～-70 ℃ by grading control.
6, the method for the tail gas that polysilicon produced is produced in recycling according to claim 1, and the pressure of the hydrogen chloride of the gaseous state that wherein desorbs and dichloro-dihydro silicon is controlled as 0.1～2.0Mpa.
7. the method for the tail gas that polysilicon produced is produced in recycling according to claim 1, and the pressure of the hydrogen chloride of the gaseous state that wherein desorbs and dichloro-dihydro silicon is 0.1～2.0Mpa by grading control.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101210581A CN101376078B (en) | 2007-08-29 | 2007-08-29 | Method for recovering and processing tail gas produced from production of polycrystalline silicon |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101210581A CN101376078B (en) | 2007-08-29 | 2007-08-29 | Method for recovering and processing tail gas produced from production of polycrystalline silicon |
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| CN101376078A CN101376078A (en) | 2009-03-04 |
| CN101376078B true CN101376078B (en) | 2011-04-13 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101885473B (en) * | 2010-06-28 | 2012-01-11 | 天津大学 | Green and environment-friendly recycling method of trichlorosilane tail gas |
| CN102389687B (en) * | 2011-09-28 | 2014-07-02 | 四川瑞能硅材料有限公司 | Method for promoting purity of chlorine hydride recycled by reduction unit of polysilicon tail gas separating system |
| CN103466548A (en) * | 2013-09-03 | 2013-12-25 | 新特能源股份有限公司 | Method and device for separating and recycling tail gas based on polycrystalline silicon dry method |
| CN110240165B (en) * | 2018-03-07 | 2021-05-11 | 新特能源股份有限公司 | Method and device for recovering dichlorosilane from polycrystalline silicon reduction tail gas |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005011095A1 (en) * | 2005-03-08 | 2006-09-14 | Schäffer, Lars | Process to dispose of surplus silane arising from manufacture of electronic components by surrendering to wet washing with hydrogen fluoride |
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2007
- 2007-08-29 CN CN2007101210581A patent/CN101376078B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005011095A1 (en) * | 2005-03-08 | 2006-09-14 | Schäffer, Lars | Process to dispose of surplus silane arising from manufacture of electronic components by surrendering to wet washing with hydrogen fluoride |
Non-Patent Citations (1)
| Title |
|---|
| 刘建军.多晶硅生产中回收氢气的净化.《有色冶炼》.2000,第29卷(第6期),第17－19页. * |
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