CN102795628B - Improved method for preparing trichlorosilane by using low-pressure synthetic technology - Google Patents
Improved method for preparing trichlorosilane by using low-pressure synthetic technology Download PDFInfo
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- CN102795628B CN102795628B CN201210275343.XA CN201210275343A CN102795628B CN 102795628 B CN102795628 B CN 102795628B CN 201210275343 A CN201210275343 A CN 201210275343A CN 102795628 B CN102795628 B CN 102795628B
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Abstract
The invention discloses an improved method for preparing trichlorosilane by using low-pressure synthetic technology, comprising the process and equipment for preparing the trichlorosilane TCS by using a silicon powder (Si) and hydrogen chloride (HCl) low-temperature synthetic method. The equipment mainly comprises a dichlorosilane DCS evaporator and a fluidized bed reactor. The improved method comprises: gasifying the dichlorosilane DCS of rectification section in the evaporator, feeding the gaseous dichlorosilane DCS into the fluidized bed reactor to react with excess HCl to prepare the trichlorosilane; and after the DSC of the rectification section aggregated in a certain period finishes reaction, transferring to the process for preparing the trichlorosilane TCS by using the silicon powder (Si) and hydrogen chloride (HCl) low-temperature synthetic method. The improved method is both a new method for preparing the TSC, and a solution to a disadvantage of the conventional improved Siemens method: DSC enrichment; and is safe and stable, simple in technology, and easy in operation.
Description
Technical field
The present invention relates to a kind of improved low pressure synthesis technique and prepare the method for trichlorosilane, belong to improved Siemens and prepare solar-grade polysilicon technical field.
Background technology
It is the most universal a kind of technical process that current improved Siemens is prepared solar-grade polysilicon technical process, whole world polysilicon is prepared factory and is surpassed 90% what use is this technical process, and this technique is current also improves the phase in development, also will be in occupation of main flow Technology within following considerable time.
But exploitation and the development of several generations have also been experienced in this technical process, concentrate on especially recently and in TCS preparation technology, occurred several different flow processs: the low-pressure synthesis of silica flour (Si) and hydrogenchloride (HCl), silicon tetrachloride (STC) hydrogenation conversion method (wherein have again hot hydrogenation and cold hydrogenation minute) and the anti-discrimination method of DCS, these three kinds of methods emphasize particularly on different fields a little, and visual concrete different flow processs are selected.
US-5118485[P] reported a kind of method of cold hydrogenation: by STC, in fluidized-bed reactor, be reduced into trichlorosilane, the proportionlity of transformation efficiency and STC and the H2 of silicon tetrachloride has been discussed.Reaction equation is:
3SiCl
4+2H
2+Si→4SiHCl
3
CN201010514102.7[P] the low pressure synthesis technique of a kind of Si and HCl disclosed, by making Si and HCl in the absolute pressure of 0.5-30atm, at the temperature of 250-1100 ℃, in fluidized-bed reactor, agitated bed reactor or fixed-bed reactor, produce the method for trichlorosilane.
Japan postpones publication 56-73617, discloses a kind of copper powder of using as the method for Catalyst Production TCS.Simultaneously by silica flour, HCl, STC, H2 in fluidized-bed, at 350-600 ℃, reaction can generate TCS by Si and HCl, STC is also converted into the method for TCS simultaneously.
Japan postpones publication 60-36318, discloses a kind of method that STC is changed into TCS, and it is that STC and H2 pass through silicon ion, and reaction at 500-700 ℃ adopts CuCl as catalyzer.
Thinking of the present invention, the low pressure synthesis technique based on Si and HCl, selects its major equipment fluidized-bed reactor as reacting environment, carries out new chemical reaction.The present invention has carried out research constantly to the various processing parameters of low-pressure synthesis reaction, foregoing invention is improved: cancelled copper powder, CuCl catalyzer; Temperature of reaction and pressure have been reduced.
Summary of the invention
The object of the invention is the improvement of the fluidized-bed reactor method technique based on silica flour and hydrogenchloride, retain and improved its major equipment fluidized-bed as principal reaction place, provide a kind of improved low pressure synthesis technique to prepare the method for trichlorosilane, used dichloro-dihydro silicon DCS to transform the method for preparing trichlorosilane TCS.The method is the preparation method of a kind of new TCS, has also solved the drawback of a traditional improved Siemens simultaneously: the problem of DCS enrichment.Technique is succinct, easy to operate, safe, stable.
To achieve these goals, the present invention adopts following technical scheme:
Improved low pressure synthesis technique is prepared a method for trichlorosilane, comprises silica flour (Si) and hydrogenchloride
(HCl) low-pressure synthesis is prepared flow process and the equipment of trichlorosilane TCS, described equipment mainly comprises dichloro-dihydro silicon vaporizer and fluidized-bed reactor, the dichloro-dihydro silicon DCS of rectifying workshop section is gasified in vaporizer, then the dichloro-dihydro silicon DCS of gaseous state is passed into fluidized-bed reactor and excessive HCl reacts to prepare trichlorosilane; After the DCS reaction of assembling in rectifying workshop section certain hour finishes, the low-pressure synthesis that proceeds to silica flour (Si) and hydrogenchloride (HCl) is prepared the flow process of trichlorosilane TCS.
Dichloro-dihydro silicon DCS gasification in vaporizer of described rectifying workshop section is: by the silicon tetrachloride STC of the bottom discharge liquid state from the trichlorosilane TCS of rectifying workshop section product rectifying tower, or the liquid STC of other workshop sections or equipment, is transported to DCS vaporizer and meets the requirements of liquid level: 5～70%; Then by the top product from rectifying workshop section cut light tower: the dichloro-dihydro silicon DCS of liquid low-temp low-pressure is transported to the shell side section of vertical DCS vaporizer, by heating medium for heating, arrive certain temperature, and by conveying gas, enter shell side section pressure is brought up in certain pressure range.
Described improved low pressure synthesis technique is prepared the method for trichlorosilane, specifically comprises the following steps:
(1) in fluidized-bed reactor, put in advance the levels of metal silica flour of certain altitude;
(2) by the silicon tetrachloride STC of the bottom discharge liquid state from the trichlorosilane TCS of rectifying workshop section product rectifying tower, or the liquid STC of other workshop sections or equipment, be transported to DCS vaporizer and meet the requirements of liquid level: 5～70%;
(3) by the top product from rectifying workshop section cut light tower: the dichloro-dihydro silicon DCS of liquid low-temp low-pressure is transported to the shell side section of vertical DCS vaporizer, by heating medium for heating to 100～200 ℃, and by conveying gas, enter shell side section pressure is brought up to 0.1～2.0MPa;
(4) a certain amount of pressure is that the HCl gas of 0.1～1.0 MPa sparger by fluidized-bed bottom blows to the silica flour reaction bed that silica flour bed gets up to form the fluidisation of certain altitude;
(5) DCS under the state of above-mentioned (3) is passed into fluidized-bed, DCS and HCl to keep 1:1～5
The feed rate of mol ratio;
(6) often in DCS vaporizer, pass into a certain amount of STC to keep a metastable ratio at regular intervals, also will keep liquid level relatively stable of DCS vaporizer simultaneously, the mass rate of DCS will be controlled within the scope of 100～10000kg/h;
(7) after the DCS reaction of assembling finishes, stop immediately DCS to the charging of vaporizer in rectifying workshop section certain hour, continue again to pass into silicon tetrachloride STC approximately 10～100 min simultaneously;
(8) then, then continue to keep the flow velocity that HCl is identical constant, continue approximately 5～100 min;
(9) then, change the amount of HCl, start to make it to react with silica flour, and adjust both ratios, the low-pressure synthesis that proceeds to silica flour and hydrogenchloride HCl is prepared the technique of trichlorosilane TCS.
The pressure of described fluidized-bed is 0.1～1.0 MPa, and temperature is 100～500 ℃.
Advantage of the present invention:
(1) the present invention has enriched the purposes of fluidized-bed reactor in the low-pressure process of Si and HCl, has realized a kind of new reaction process; Compare with silicon tetrachloride (STC) hydrogenation conversion method, reaction pressure reduces greatly, and security is improved and has reduced energy consumption; Compare with the anti-discrimination method of DCS, realized the conversion process flow process of a kind of new DCS, do not need catalyzer, react flexible, easy to operate.
(2) the present invention is the improvement of the fluidized-bed reactor method technique based on silica flour and hydrogenchloride, retain and improved its major equipment fluidized-bed as principal reaction place, propose the technical process that a kind of new use DCS transforms preparation TCS, solved the drawback of a traditional improved Siemens: the problem of DCS enrichment.In DCS polycrystalline factory, be a by product, boiling point is 8 ℃, compares with other chlorosilane, and hazard level is the highest, if long-term aggregated surpasses certain proportion, will affect routine operating pressure and the temperature of each technique unit, and forms very large potential safety hazard.The present invention, the high by product of this danger of DCS, is transformed into the raw material TCS that produces polysilicon with a kind of new technique, can be described as and turn waste into wealth.
Accompanying drawing explanation
Fig. 1 is the process flow sheet of DCS vaporizer;
Wherein:
A-DCS gasifier
1.-liquid DCS
2.-gaseous state DCS
3.-drop a hint
4.-heating agent inlet wire
5.-heating agent outlet
Fig. 2 is the process flow sheet of fluidized-bed reactor;
Wherein:
A-fluidized-bed reactor
1.-gaseous state dichloro-dihydro silicon
2.-hydrogen chloride gas
3.-silica flour
4.-hydrogen
5.-heating agent inlet wire
6.-deslagging outlet
7.-gaseous product chlorosilane
8.-drop a hint
9.-heating agent outlet
The process flow sheet of the preparation of the TCS that Fig. 3 is complete, separation and purifying.
Embodiment
Improved low pressure synthesis technique is prepared the method for trichlorosilane, comprises following process:
(1) in fluidized-bed reactor, put in advance the levels of metal silica flour of certain altitude;
(2) by the silicon tetrachloride STC of the bottom discharge liquid state from the trichlorosilane TCS of rectifying workshop section product rectifying tower, or the liquid STC of other workshop sections or equipment, be transported to DCS vaporizer and meet the requirements of liquid level: 5～70%;
(3) by the top product from rectifying workshop section cut light tower: the dichloro-dihydro silicon DCS of liquid low-temp low-pressure is transported to the shell side section of vertical DCS vaporizer, by heating medium for heating to 100～200 ℃, and by conveying gas, enter shell side section pressure is brought up to 0.1～2.0MPa;
(4) the HCl gas that a certain amount of pressure is 0.1～1.0MPa blows to by the sparger of fluidized-bed bottom the silica flour reaction bed that silica flour bed gets up to form the fluidisation of certain altitude;
(5) DCS under the state of above-mentioned (3) is passed into fluidized-bed, DCS and HCl to keep the feed rate of the mol ratio of 1:1～5;
(6) often in DCS vaporizer, pass into a certain amount of STC to keep a metastable ratio at regular intervals, also will keep liquid level relatively stable of DCS vaporizer simultaneously, the mass rate of DCS will be controlled within the scope of 100～10000kg/h;
(7) after the DCS reaction of assembling finishes, stop immediately DCS to the charging of vaporizer in rectifying workshop section certain hour, continue again to pass into silicon tetrachloride STC approximately 10～100 min simultaneously;
(8) then, then continue to keep the flow velocity that HCl is identical constant, continue approximately 5～100 min;
(9) then, change the amount of HCl, start to make it to react with silica flour, and adjust both ratios, the low-pressure synthesis that proceeds to silica flour and hydrogenchloride HCl is prepared the technique of trichlorosilane TCS.
Below in conjunction with embodiment, the present invention is further illustrated.
As Fig. 1, first by rectifying workshop section being taken off to the product of the tower inner top of light constituent: the liquid DCS of gathering is transferred to vaporizer with canned-motor pump or with conveying gas (H2) force feed.Before transmission, the STC of pumping liquid level in advance approximately 1% is to DCS vaporizer, and main purpose is: the pressure and temperature that regulates vaporizer, then the liquid DCS in normal temperature is transmitted, to liquid level, in 90% left and right, then with steam-heated evaporator, arrive approximately 400 ℃, now pressure is in 15bar left and right.The pressure of vaporizer, temperature and liquid level are regulated automatically by teletransmission DCS system.In addition, vaporizer is equipped with: safety relief device (PSV), liquid level and pressure interlocking system (interlock) and emergency venting system (ESD).Start vaporizer, when processing parameter reaches after set(ting)value, gaseous state DCS carries to fluidized-bed.
As Fig. 2, before DCS is transferred to fluidized-bed, first the HCl of corresponding proportion is passed into wherein, then gaseous state DCS is transferred to fluidized-bed by pressure-acting, now the pressure of fluidized-bed is 0.1bar, and temperature is 500 ℃, and the temperature of fluidized-bed adopts thermal oil to control as heating agent, due to pressure and temperature is had relatively high expectations, the pressure and temperature of fluidized-bed has warning and emergency stopping system to guarantee that it is in normal range of operation.Above-mentioned two kinds of gases main generation in fluidized-bed reacted as follows:
SiH
2Cl
4+HCl→SiHCl
3+H
2
DCS vaporizer adopts heating medium for heating, processing flow 10～13000kg/h of DCS, and the flow of heating agent should be mutually: 15～300kg/h.
The corresponding rate of flow meter of table 1.DCS and steam
| DCS?(Kg/h) | Heating agent (Kg/h) |
| 10 | 15 |
| 50 | 20 |
| 100 | 30 |
| 300 | 45 |
| 400 | 60 |
| 500 | 75 |
| 600 | 11.54 |
| 700 | 23.08 |
| 800 | 34.62 |
| 900 | 46.16 |
| … | … |
| 13000 | 300 |
The molar ratio of HCl and DCS is about 0～3, and its upper limit is determined depending on adding the amount of silica flour, and a wider range is easier to realize.
The feed rate of table 2.DCS and HCl
| DCS?(Kg/h) | HCl?(Kg/h) |
| 50 | 17.8 |
| 100 | 38.30 |
| 200 | 80.30? |
| 300 | 125.92 |
| 400 | 175.20 |
| 500 | 228.13 |
| … | … |
| 13000 | 5000 |
Result:
We are furnished with sampling system on the outlet line of fluidized-bed, analyze the laboratory report that draws table 3.
The analysis report of table 3. fluidized-bed gas product
From analysis report result, can draw: fixed bed has improved transformation efficiency and the production efficiency of product widely to the improvement of fluidized-bed, a transformation efficiency is for being not less than 81%(molar percentage).Can find out in addition, leaving DCS and HCl in the product gas of fluidized-bed does not have complete reaction, it is separated to recirculation and return in reactor and react.
Claims (3)
1. an improved low pressure synthesis technique is prepared the method for trichlorosilane, comprise that the low-pressure synthesis of silica flour (Si) and hydrogenchloride (HCl) prepares flow process and the equipment of trichlorosilane TCS, described equipment mainly comprises dichloro-dihydro silicon (DCS) vaporizer and fluidized-bed reactor, it is characterized in that: the dichloro-dihydro silicon DCS of rectifying workshop section is gasified in vaporizer, then the dichloro-dihydro silicon DCS of gaseous state is passed into fluidized-bed reactor and excessive HCl reacts to prepare trichlorosilane; After the DCS reaction of assembling in rectifying workshop section certain hour finishes, the low-pressure synthesis that proceeds to silica flour (Si) and hydrogenchloride (HCl) is prepared the flow process of trichlorosilane TCS;
Specifically comprise the following steps:
(1) in fluidized-bed reactor, put in advance the levels of metal silica flour of certain altitude;
(2) by the silicon tetrachloride STC of the bottom discharge liquid state from the trichlorosilane TCS of rectifying workshop section product rectifying tower, or the liquid STC of other workshop sections or equipment, be transported to DCS vaporizer and meet the requirements of liquid level: 5～70%;
(3) by the top product from rectifying workshop section cut light tower: the dichloro-dihydro silicon DCS of liquid low-temp low-pressure is transported to the shell side section of vertical DCS vaporizer, by heating medium for heating to 100～200 ℃, and by conveying gas, enter shell side section pressure is brought up to 0.1～2.0MPa;
(4) the HCl gas that a certain amount of pressure is 0.1～1.0MPa blows to by the sparger of fluidized-bed bottom the silica flour reaction bed that silica flour bed gets up to form the fluidisation of certain altitude;
(5) DCS under the state of above-mentioned (3) is passed into fluidized-bed, DCS and HCl to keep the feed rate of the mol ratio of 1:1～5;
(6) often in DCS vaporizer, pass into a certain amount of STC to keep a metastable ratio at regular intervals, also will keep liquid level relatively stable of DCS vaporizer simultaneously, the mass rate of DCS will be controlled within the scope of 100～10000kg/h;
(7) after the DCS reaction of assembling finishes, stop immediately DCS to the charging of vaporizer in rectifying workshop section certain hour, continue again to pass into silicon tetrachloride STC approximately 10～100 min simultaneously;
(8) then, then continue to keep the flow velocity that HCl is identical constant, continue approximately 5～100 min;
(9) then, change the amount of HCl, start to make it to react with silica flour, and adjust both ratios, the low-pressure synthesis that proceeds to silica flour and hydrogenchloride HCl is prepared the technique of trichlorosilane TCS.
2. improved low pressure synthesis technique according to claim 1 is prepared the method for trichlorosilane, it is characterized in that: the process that the dichloro-dihydro silicon DCS of described rectifying workshop section gasifies in vaporizer is: by the silicon tetrachloride STC of the bottom discharge liquid state from the trichlorosilane TCS of rectifying workshop section product rectifying tower, or the liquid STC of other workshop sections or equipment, is transported to DCS vaporizer and meets the requirements of liquid level: 5～70%; Then by the top product from rectifying workshop section cut light tower: the dichloro-dihydro silicon DCS of liquid low-temp low-pressure is transported to the shell side section of vertical DCS vaporizer, by heating medium for heating, arrive certain temperature, and by conveying gas, enter shell side section pressure is brought up in certain pressure range.
3. improved low pressure synthesis technique according to claim 1 is prepared the method for trichlorosilane, it is characterized in that: the pressure of described fluidized-bed is 0.1～1.0MPa, and temperature is 100～500 ℃.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100001236A1 (en) * | 2008-07-01 | 2010-01-07 | Yongchae Chee | Method of producing trichlorosilane (TCS) rich product stably from a fluidized gas phase reactor (FBR) and the structure of the reactor |
| CN101808938A (en) * | 2007-08-29 | 2010-08-18 | 动力工程公司 | Process for producing trichlorosilane |
| CN101955187A (en) * | 2010-10-21 | 2011-01-26 | 天津大学 | Method and apparatus for preparing trichlorosilane through reaction rectification by using proportionate reaction |
| CN201809177U (en) * | 2010-09-30 | 2011-04-27 | 河南尚宇新能源股份有限公司 | Rectifying equipment for purifying trichlorosilane |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009096678A (en) * | 2006-11-30 | 2009-05-07 | Mitsubishi Materials Corp | Apparatus for production of trichlorosilane |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101808938A (en) * | 2007-08-29 | 2010-08-18 | 动力工程公司 | Process for producing trichlorosilane |
| US20100001236A1 (en) * | 2008-07-01 | 2010-01-07 | Yongchae Chee | Method of producing trichlorosilane (TCS) rich product stably from a fluidized gas phase reactor (FBR) and the structure of the reactor |
| CN201809177U (en) * | 2010-09-30 | 2011-04-27 | 河南尚宇新能源股份有限公司 | Rectifying equipment for purifying trichlorosilane |
| CN101955187A (en) * | 2010-10-21 | 2011-01-26 | 天津大学 | Method and apparatus for preparing trichlorosilane through reaction rectification by using proportionate reaction |
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Address after: 230088 in the high tech Industrial Development Zone, No. 669, Changjiang West Road, Hefei City, Anhui Province Patentee after: EAST CHINA ENGINEERING SCIENCE AND TECHNOLOGY Co.,Ltd. Address before: 230024 No. 70 Wangjiang East Road, Anhui, Hefei Patentee before: EAST CHINA ENGINEERING SCIENCE AND TECHNOLOGY Co.,Ltd. |