CN103950937A - Chlorosilane purification method - Google Patents
Chlorosilane purification method Download PDFInfo
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Abstract
The invention discloses a chlorosilane purification method. The method comprises the following steps: carrying out first to fifth rectification purification on first to fifth chlorosilane to obtain first to fifth tower top steams and first to fifth tower bottom liquids; 2, condensing the first tower top steam to obtain a first chlorosilane condensate liquid, and returning parts of the first chlorosilane condensate liquid into a first rectifying tower; 3, carrying out first to fifth reboiling treatment on the first to fifth tower bottom liquids to obtain first to fifth reboiling steams, and returning the first to fifth reboiling steams into first to fifth rectification towers; and 4, carrying out the first to fourth reboiling treatment by using the second to fifth tower top steams to obtain second to fifth chlorosilane condensate liquids. Compared with simple coupled rectification technologies, the above five tower continuous coupling method has a more obvious energy saving effect, enables the energy consumption to be reduced by 80%, and solves a problem that energy consumed by a purification process of a polysilicon system is high, so the production cost is reduced.
Description
Technical field
The present invention relates to field polysilicon, particularly, the present invention relates to chlorosilane method of purification.
Background technology
Polysilicon is a kind of ultra-pure material, for unicircuit, electron device and solar cell, is the foundation stone of information and New Energy Industry, is that country encourages the strategic material of first developing, and is also the Product and industry of state key encourage growth.2012, be subject to two anti-impacts of global economic crisis and European Union, how the continued downturn of polysilicon market, reduce production of polysilicon cost, how to enhance the core competitiveness of enterprises, and becomes the top priority of the long-term sustainable development of each polysilicon enterprise.
The main production method of current domestic polysilicon is improved Siemens, mainly comprises that trichlorosilane is synthetic, rectification and purification, reduction, reduction tail gas dry process reclaim and five operations of hydrogenation.Rectification and purification, for reduction operation provides high pure raw material, is the important procedure of polysilicon system.The ultra-high purity of polysilicon requires the foreign matter content of refined product to reach ppta rank (10-12), purity reaches 9 " 9 ", inevitable requirement high reflux ratio and high number of theoretical plate, must need relatively high heat exhaustion, the energy consumption of purification process is one of main energy consumption of polysilicon system, and the energy consumption that therefore reduces purification process is one of effective way reducing polysilicon cost.
But, need further improvement for the method for chlorine purification silane at present.
Summary of the invention
The present invention is intended to one of solve the problems of the technologies described above at least to a certain extent.For this reason, one object of the present invention is to propose a kind of chlorosilane method of purification, wherein, chlorosilane method of purification can reach expands as 5 towers by the quantity of coupled by 2 or 3 towers, realize thus the continuous coupled energy-saving effect of five towers more obvious, Energy Intensity Reduction 80%, has solved the problem of purification process high energy consumption in polysilicon system, reduce enterprise's production cost, enhance the core competitiveness of enterprises.
According to an aspect of the present invention, the present invention proposes a kind of chlorosilane method of purification, comprising:
(1) in the first to the 5th rectifying tower, carry out accordingly respectively the first to the 5th rectification and purification by first to pentachloro-silane, to obtain respectively liquid at the bottom of the first to the 5th overhead vapours and the first to the 5th tower;
(2) described the first overhead vapours is carried out to condensation process in condenser, to obtain the first chlorosilane condensate liquid, and a part for described the first chlorosilane condensate liquid is back in described the first rectifying tower;
(3) part for liquid at the bottom of the described first to the 5th tower is carried out respectively accordingly in the first to the 5th reboiler to first to the 5th processing of boiling again, to obtain first to the 5th steam that boils again, and described first to the 5th steam that boils is again back to respectively in the described first to the 5th rectifying tower accordingly; And
(4) the described second to the 5th overhead vapours is back to respectively accordingly in step (3) successively for described first to fourth processing of boiling again, to obtain respectively second to pentachloro-silane phlegma, and described second part to pentachloro-silane phlegma is back to respectively in the described second to the 5th rectifying tower accordingly.
The above embodiment of the present invention chlorosilane method of purification is compared with simple coupling rectification technique, the continuous coupled energy-saving effect of five towers is more obvious, and Energy Intensity Reduction 80% has solved the problem of purification process high energy consumption in polysilicon system, reduce enterprise's production cost, enhance the core competitiveness of enterprises.
In some embodiments of the invention, it is 32～42 degrees Celsius for the temperature of the low-temperature receiver of described the first condensation process.
In some embodiments of the invention, be the high-temperature water of 150 degrees Celsius for the described second thermal source that boils again processing, described high-temperature water is to utilize the waste heat of polysilicon reduction operation to produce.
In some embodiments of the invention, for carrying out respectively the described first to the 5th rectifying tower of the described first to the 5th rectification and purification, the tower top temperature difference of the tower reactor of described the first rectifying tower and Second distillation column is 8-12 degree Celsius, the tower top temperature difference of the tower reactor of described Second distillation column and the 3rd rectifying tower is 8-12 degree Celsius, the tower top temperature difference of the tower reactor of described the 3rd rectifying tower and the 4th rectifying tower is 8-12 degree Celsius, and the tower top temperature difference of the tower reactor of described the 4th rectifying tower and the 5th rectifying tower is 8-12 degree Celsius.
In some embodiments of the invention, in the described first to the 5th rectifying tower, the pressure reduction at the bottom of tower top and the tower of each rectifying tower is 0.01～0.06MPa.
In some embodiments of the invention, the annexation between the described first to the 5th rectifying tower is divided into and is connected in series, is connected in parallel or onrelevant connection with the described first to the 5th opening for feed.
In some embodiments of the invention, described second to pentachloro-silane be respectively a part for liquid at the bottom of the part of described first to fourth chlorosilane condensate liquid or first to fourth tower accordingly.
In some embodiments of the invention, the mean pressure in the described first to the 5th rectifying tower is raise successively or reduce successively.
In some embodiments of the invention, described first in pentachloro-silane at least one from different chlorosilane feedwaies.
In some embodiments of the invention, described first to pentachloro-silane be the hydrogenation condensation material that is selected from hydrogenation process in polysilicon system, dry method recovery process dry back rewinding, process the recovery tower raw material of the each group of low impurity that boils of tower height, further process at least one of rectifying tower raw material of hydrogenation condensation material and recovery tower product.
Additional aspect of the present invention and advantage in the following description part provide, and part will become obviously from the following description, or recognize by practice of the present invention.
Brief description of the drawings
Above-mentioned and/or additional aspect of the present invention and advantage accompanying drawing below combination is understood becoming the description of embodiment obviously and easily, wherein:
Fig. 1 is the structural representation of chlorosilane method of purification according to an embodiment of the invention.
Fig. 2 is the structural representation of chlorosilane method of purification according to another embodiment of the invention.
Fig. 3 is the structural representation of chlorosilane method of purification according to another embodiment of the invention.
Fig. 4 is the structural representation of chlorosilane method of purification according to another embodiment of the invention.
Embodiment
Describe embodiments of the invention below in detail, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has the element of identical or similar functions from start to finish.Be exemplary below by the embodiment being described with reference to the drawings, be intended to for explaining the present invention, and can not be interpreted as limitation of the present invention.
In description of the invention, it will be appreciated that, term " " center ", " longitudinally ", " laterally ", " length ", " width ", " thickness ", " on ", D score, " front ", " afterwards ", " left side ", " right side ", " vertically ", " level ", " top ", " end " " interior ", " outward ", " clockwise ", orientation or the position relationship of instructions such as " counterclockwise " are based on orientation shown in the drawings or position relationship, only the present invention for convenience of description and simplified characterization, instead of device or the element of instruction or hint indication must have specific orientation, with specific orientation structure and operation, therefore can not be interpreted as limitation of the present invention.
In addition, term " first ", " second " be only for describing object, and can not be interpreted as instruction or hint relative importance or the implicit quantity that indicates indicated technical characterictic.Thus, one or more these features can be expressed or impliedly be comprised to the feature that is limited with " first ", " second ".In description of the invention, the implication of " multiple " is two or more, unless otherwise expressly limited specifically.
In the present invention, unless otherwise clearly defined and limited, the terms such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, and for example, can be to be fixedly connected with, and can be also to removably connect, or connect integratedly; Can be mechanical connection, can be also electrical connection; Can be to be directly connected, also can indirectly be connected by intermediary, can be the connection of two element internals.For the ordinary skill in the art, can understand as the case may be above-mentioned term concrete meaning in the present invention.
In the present invention, unless otherwise clearly defined and limited, First Characteristic Second Characteristic it " on " or D score can comprise that the first and second features directly contact, also can comprise that the first and second features are not directly contacts but by the other feature contact between them.And, First Characteristic Second Characteristic " on ", " top " and " above " comprise First Characteristic directly over Second Characteristic and oblique upper, or only represent that First Characteristic level height is higher than Second Characteristic.First Characteristic Second Characteristic " under ", " below " and " below " comprise First Characteristic under Second Characteristic and tiltedly, or only represent that First Characteristic level height is less than Second Characteristic.
Though some tower group of rectification and purification has adopted differential pressure heat coupling at present, has reduced energy consumption, all adopts two towers or three-tower differential pressure thermal coupling, coupled limited amount.While design, for ensureing that tower occurs also normally producing while fluctuation in the fluctuation of tower pressure or heat exchange inventory, two material temperature difference of coupled and heat-exchange are generally 15～30 DEG C in the past; In tower, tower top tower base pressure is poor larger simultaneously, gets 0.05～0.3MPa when design, and this has all limited differential pressure heat coupled quantity, therefore can not farthest reduce energy consumption.
Describe the chlorosilane method of purification of the embodiment of the present invention below in detail.
Comprise according to the chlorosilane method of purification of the embodiment of the present invention:
(1) in the first to the 5th rectifying tower, carry out accordingly respectively the first to the 5th rectification and purification by first to pentachloro-silane, to obtain respectively liquid at the bottom of the first to the 5th overhead vapours and the first to the 5th tower;
(2) the first overhead vapours is carried out in condenser to condensation process, to obtain the first chlorosilane condensate liquid, and a part for the first chlorosilane condensate liquid is back in the first rectifying tower;
(3) part for liquid at the bottom of the first to the 5th tower is carried out respectively accordingly in the first to the 5th reboiler to first to the 5th processing of boiling again, to obtain first to the 5th steam that boils again, and first to the 5th steam that boils is again back to respectively in the first to the 5th rectifying tower accordingly; And
(4) the second to the 5th overhead vapours is back to respectively accordingly in step (3) successively for first to fourth processing of boiling again, to obtain respectively second to pentachloro-silane phlegma, and second part to pentachloro-silane phlegma is back to respectively in the second to the 5th rectifying tower accordingly.
The chlorosilane method of purification of the above embodiment of the present invention is compared with simple coupling rectification technique, the continuous coupled energy-saving effect of five towers is more obvious, and Energy Intensity Reduction 80% has solved the problem of purification process high energy consumption in polysilicon system, reduce enterprise's production cost, enhance the core competitiveness of enterprises.
According to a particular embodiment of the invention, it is 32～42 degrees Celsius for the temperature of the low-temperature receiver of described the first condensation process.Low-temperature receiver particular type is also not particularly limited, for example, can be the recirculated water of 32～42 degrees Celsius.Be the high-temperature water of 150 degrees Celsius for the second thermal source that boils again processing, high-temperature water is to utilize the waste heat of polysilicon reduction operation to produce.The chlorosilane method of purification of the above embodiment of the present invention only need to provide low-temperature receiver and thermal source for condenser and the 5th reboiler thus, and mutually makes full use of by internal system cold and heat.Chlorosilane method of purification according to the abovementioned embodiments of the present invention, can make full use of heat coupling, has saved the second auxiliary condenser to the 5th rectifying tower, and then has significantly saved energy consumption.
According to a particular embodiment of the invention, it is 8 degrees Celsius by adopting the chlorosilane method of purification of the above-mentioned enforcement of the present invention can make the tower reactor of rectifying tower at different levels be down to minimum with the mean temperature difference of the next stage rectifying tower tower top being coupled with it.Be specially, the tower top temperature difference of the tower reactor of the first rectifying tower and Second distillation column is 8-12 degree Celsius, the tower top temperature difference of the tower reactor of described Second distillation column and the 3rd rectifying tower is 8-12 degree Celsius, the tower top temperature difference of the tower reactor of described the 3rd rectifying tower and the 4th rectifying tower is 8-12 degree Celsius, and the tower top temperature difference of the tower reactor of described the 4th rectifying tower and the 5th rectifying tower is 8-12 degree Celsius.By adopting the mode of connection of the above embodiment of the present invention, can reduce the temperature difference pressure reduction thermal coupling tower is counted to quantitative limitation thus.The high-temperature water that simultaneously only the first rectifying tower and the 5th rectifying tower need be adopted respectively to low-temperature receiver-recirculated water and thermal source-150 degree Celsius, can expand pressure reduction thermal coupling tower quantity to 5 towers by 2 or 3 traditional towers.Therefore, five towers only need have a tower to need low-temperature receiver, and a tower needs thermal source, thus can be by low-temperature receiver, thermal source Energy Intensity Reduction to 80%.
According to a particular embodiment of the invention, by adopting above-mentioned annexation, can also, by the tower top of same tower and the poor minimum 0.01MPa that is reduced to of tower base pressure, be specially, the pressure reduction at the bottom of first to the 5th tower top and tower can be 0.01～0.06MPa.According to a particular embodiment of the invention, the pressure in the first to the 5th rectifying tower can be raise successively or reduce successively.
According to a particular embodiment of the invention, the annexation between the first to the 5th rectifying tower is divided into and is connected in series, is connected in parallel or onrelevant connection with the first to the 5th opening for feed.
Be specially, be connected in series and refer to that each rectifying tower connects according to following mode of connection, make second to pentachloro-silane be respectively a part for liquid at the bottom of the part of first to fourth chlorosilane condensate liquid or first to fourth tower accordingly.
First, the opening for feed of the first rectifying tower passes into the pending raw material of chlorosilane, the second opening for feed to the 5th rectifying tower is connected with the liquid outlet of first to fourth rectifying tower or the pump discharge of first to fourth reflux pump respectively successively, so that at least one of the de-light constituent that the pump discharge of the de-heavy constituent that the liquid outlet of first to fourth rectifying tower is discharged and first to fourth reflux pump is discharged is delivered to the second to the 5th rectifying tower.In the time adopting series system and tower to press from low to high, except last step rectifying tower, the tower tower reactor extraction of de-function light arranges a column bottoms pump during to the charging of next stage rectifying tower.
Be connected in parallel and refer to that the opening for feed of at least one rectifying tower in the first to the 5th rectifying tower is connected with same chlorosilane feedway respectively independently.First to pentachloro-silane all from identical chlorosilane feedway.
Onrelevant connection refers to that the opening for feed of at least one rectifying tower in the first to the 5th rectifying tower is connected from different chlorosilane feedwaies respectively independently, also can be understood as and in five rectifying tower, have at least the chlorosilane source of two rectifying tower different, have at least two rectifying tower opening for feeds to be connected from different chlorosilane feedwaies.
Wherein, first to pentachloro-silane can for be selected from hydrogenation process in polysilicon system hydrogenation condensation material, dry method recovery process dry back rewinding, process the recovery tower raw material of the each group of low impurity that boils of tower height, further process the rectifying tower raw material of hydrogenation condensation material and recovery tower product.
According to a particular embodiment of the invention, the chlorosilane method of purification of the embodiment of the present invention can utilize the purifying plant with structure shown in Fig. 1-2 to carry out, and as shown in Figure 1-2, this device specifically comprises:
Chlorosilane method of purification as shown in Figure 1-2, comprising: the first rectifying tower to the five rectifying tower (T1-T5); The first to the 5th reboiler (E2-E6); The first to the 5th reflux pump (P1-P5); A condenser E1.
Wherein, the first to the 5th rectifying tower (T1-T5) have be positioned at this rectifying tower middle part opening for feed (T11-T51), be positioned at this rectifying tower top air outlet (T12-T52), be positioned at this rectifier bottoms liquid outlet (T13-T53), be positioned at this rectifier fluid inlet (T14-T54), be positioned at this rectifying tower bottom inlet mouth (T15-T55).
The first to the 5th reboiler (E2-E6), each in the first to the 5th reboiler (E2-E6) all have be positioned at this reboiler bottom fluid inlet (E21-E61), be positioned at the air outlet (E22-E62) at this reboiler top, the condensate outlet (E24-E64) that is positioned at the steam inlet (E23-E63) on this reboiler top and is positioned at this reboiler bottom
The first to the 5th reflux pump (P1-P5), each pump in the described first to the 5th reflux pump (P1-P5) all has pump inlet (P11-P51) and pump discharge (P12-P52);
The first to the 5th return tank (V1-V5), each return tank in the described first to the 5th return tank (V1-V5) all has the tank import (V11-V51) and the tank outlet (V12-V52) that are positioned on this first to the 5th return tank;
A condenser E1, a described condenser E1 has inlet mouth E11, liquid outlet E12, low-temperature receiver import (not shown) and low-temperature receiver outlet (not shown).
According to a particular embodiment of the invention, as shown in Figure 1-2, the annexation of above-mentioned parts is:
The air outlet T12 of (1) first rectifying tower T1 is connected with the inlet mouth E11 of described condenser E1, the liquid outlet E12 of condenser E1 is connected with the import V11 of return tank V1, the outlet V12 of return tank V1 is connected with the pump inlet P11 of reflux pump P1, the pump discharge P12 of the first reflux pump P1 is connected with the fluid inlet T14 of the first rectifying tower T1, to a part of chlorosilane condensate liquid is back to the first rectifying tower T1, another chlorosilane condensate liquid is as light constituent extraction.
The fluid inlet (E21-E61) of (2) first to the 5th reboilers (E2-E6) is connected with the liquid outlet of the first to the 5th rectifying tower (T13-T53), to a part for liquid at the bottom of chlorosilane tower is heated and boiled, another portion can be used as the feeding liquid of other rectifying tower or as heavy component extraction; The first air outlet to the 5th reboiler (E22-E62) is connected with the first inlet mouth to the 5th rectifying tower (T15-T55).
The air outlet (T22-T52) of (3) second to the 5th rectifying tower (T2-T5) is connected with the steam inlet (E23-E53) of first to fourth reboiler (E2-E5), the condensate outlet (E24-E54) of first to fourth reboiler (E2-E5) be connected with the tank import (V21-V51) of the second to five return tank (V2-V5) respectively successively, the tank of the second to five return tank outlet (V22-V52) is connected with the pump inlet (P21-P51) of the second to the 5th reflux pump (P2-P5) respectively successively; The pump discharge of the second to the 5th reflux pump (P2-P5) is connected with the fluid inlet (T24-T54) of the second to the 5th rectifying tower (T2-T5), to a part for chlorosilane condensate liquid is back to the second to the 5th rectifying tower, another part chlorosilane condensate liquid can be used as that feeding liquid is delivered to the 3rd to the 5th rectifying tower (T3-T5) or as light constituent extraction.
According to a particular embodiment of the invention, the low-temperature receiver import (not shown) of condenser E1 is connected with low-temperature receiver; The steam inlet E63 of the 5th reboiler E6 is connected with thermal source.
Below with reference to Fig. 3, chlorosilane method of purification is according to an embodiment of the invention described, this chlorosilane method of purification is with five tower continuous pressure difference thermal couplings, five tower towers are pressed successively and are raise, five towers adopt series system, the function of tower is respectively de-light, de-light, de-heavy, de-heavy, de-be heavily example, the backflow charge ratio of 5 towers is 1～10.
The structural representation that its concrete chlorosilane is purified and schema are referring to Fig. 3.Operating process is: raw material S01 enters the first rectifying tower T1, overhead vapours S02 is through condenser E1 condensation, phlegma S03 enters return tank V1, phlegma S04 enters reflux pump P1, after pump, liquid is according to certain reflux ratio, a part is returned to the first rectifying tower T1 as phegma S05, and a part is as light constituent extraction S06; Produced Liquid S07 at the bottom of tower, according to certain ratio, a part enters reboiler E2, and after condensation reboiler heating vaporization, gas S08 returns to the first rectifying tower T1, and a part of Produced Liquid S09 enters Second distillation column T2 through column bottoms pump P6; The overhead vapours S11 of Second distillation column T2 enters the shell side heating medium entrance of reboiler E2, through reboiler, condensed material S12 enters return tank V2, phlegma S13 enters reflux pump P2, after pump, liquid is according to certain reflux ratio, a part is returned to Second distillation column tower T2 as phegma S14, a part is as light constituent extraction S15, Produced Liquid S16 at the bottom of tower, according to certain ratio, a part enters reboiler E3, after reboiler heating vaporization, gas S17 returns to Second distillation column T2, and a part of Produced Liquid S18 enters the 3rd rectifying tower T3 through column bottoms pump P7; The overhead vapours S20 of the 3rd rectifying tower T3 enters the shell side heating medium entrance of reboiler E3, through reboiler, condensed material S21 enters return tank V3, phlegma S22 enters reflux pump P3, after pump, liquid is according to certain reflux ratio, a part is returned to the 3rd rectifying tower T3 as phegma S23, a part enters the 4th rectifying tower T4 as extraction S24, Produced Liquid S25 at the bottom of tower, according to certain ratio, a part enters reboiler E4, after reboiler heating vaporization, gas S26 returns to the 3rd rectifying tower T3, and a part is as heavy constituent S27 extraction; The overhead vapours S28 of the 4th rectifying tower T4 enters the shell side heating medium entrance of reboiler E4, through condensation reboiler, condensed material S29 enters return tank V4, phlegma S30 enters reflux pump P4, after pump, liquid is according to certain reflux ratio, a part is returned to the 4th rectifying tower T4 as phegma S31, as product S32, extraction enters the 5th rectifying tower T5 to a part, Produced Liquid S33 at the bottom of tower, according to certain ratio, a part enters reboiler E5, after reboiler heating vaporization, gas S34 returns to the 4th rectifying tower T4, and a part is as heavy constituent S35 extraction; The overhead vapours S36 of the 5th rectifying tower T5 enters the shell side heating medium entrance of condensation reboiler E5, through condensation reboiler, condensed material S37 enters return tank V5, phlegma S38 enters reflux pump P5, after pump, liquid is according to certain reflux ratio, a part is returned to the 5th rectifying tower T5 as phegma S39, a part is as product S40 extraction, Produced Liquid S41 at the bottom of tower, according to certain ratio, a part enters reboiler E6, after reboiler heating vaporization, gas S42 returns to the 5th rectifying tower T5, and a part is as heavy constituent S43 extraction.
Below with reference to Fig. 4, chlorosilane method of purification is in accordance with another embodiment of the present invention described, this chlorosilane method of purification is with five tower continuous pressure difference thermal couplings, (taking the minimum tower of pressure as the first rectifying tower) pressed successively and reduced to five tower towers, five towers adopt series system, the function of tower is respectively de-light, de-light, de-heavy, de-heavy, de-be heavily example, the backflow charge ratio of 5 towers is 1～10.
The difference of Fig. 4 and Fig. 3: for the tower of de-function light, tower reactor extraction is during to the charging of next stage rectifying tower, presses while raising successively when five tower towers, needs column bottoms pump; In the time that five tower towers pressures reduce successively, can utilize pressure reduction charging, without column bottoms pump is set, reduce facility investment and power consumption, simultaneously because materials at bottom of tower mostly is saturated liquid, easily cause mercury vapour erosion or damage, the stability of increase system.
According to embodiments of the invention, it is suitable with the required thermal load of the first tower bottom of rectifying tower vaporizing liquid that Second distillation column overhead vapours is condensed to the required refrigeration duty of supercooled state; The 3rd rectifying tower tower top vapor condensation is suitable with the required thermal load of Second distillation column tower reactor vaporizing liquid to the required refrigeration duty of supercooled state; The 4th rectifying tower tower top vapor condensation is suitable with the required thermal load of the 3rd tower bottom of rectifying tower vaporizing liquid to the required refrigeration duty of supercooled state; The 5th rectifying tower tower top vapor condensation is suitable with the required thermal load of the 4th tower bottom of rectifying tower vaporizing liquid to the required refrigeration duty of supercooled state.The first rectifying tower, Second distillation column, the 3rd rectifying tower, the 4th tower bottom of rectifying tower be without external heat source, thermal source load reduction 80%.Second distillation column, the 3rd rectifying tower, the 4th rectifying tower and the 5th rectifying tower tower top steam total condensation or excessively cold after the condensation of condensation reboiler.Second distillation column, the 3rd rectifying tower, the 4th rectifying tower, the 5th rectifying tower tower top vapor condensation are without additional low-temperature receiver, and cold source load reduces by 80%.
According to embodiments of the invention, Second distillation column, the 3rd rectifying tower, the 4th rectifying tower and the 5th rectifying tower tower top steam total condensation or excessively cold after the condensation of condensation reboiler, without auxiliary condenser, reduce facility investment, the configuration of reduction equipment and pipeline configuration difficulty, expand the use range of differential pressure heat coupled, especially for the tower group of transformation project.
The first rectifying tower and the 5th Rectification column pressure and Temperature Setting, the first rectifying tower tower top temperature is greater than 50 DEG C, ensures that the first rectifying tower is using cheap recirculated water (32～42 DEG C) as condenser low-temperature receiver; When taking high-temperature water (130～150 DEG C) during as reboiler thermal source, the 5th tower bottom of rectifying tower temperature is less than 120 DEG C; The heat-eliminating medium high-temperature water of guarantee polysilicon reduction operation, as the thermal source of rectifying tower, is realized the exchange of purification process and reduction operation cooling and heating load, farthest reduces energy consumption.For certain component, the temperature of saturation of material and pressure are corresponding one by one, and after the first rectifying tower tower top temperature and the 5th tower bottom of rectifying tower temperature are determined, pressure is determined thereupon.The tower top tower bottom pressure difference range of rectifying tower at different levels is 0.01～0.06MPa, and the two mean temperature difference of the next stage rectifying tower tower top of the tower reactor of rectifying tower at different levels, coupling is with it 8～12 DEG C.The tower top tower reactor pressure and temperature of each tower is all definite thus.
The chlorosilane method of purification of the above embodiment of the present invention has reduced the temperature difference of coupled and heat-exchange two materials, thus the quantity of differential pressure heat coupled is expanded as to 5 towers by 2 or 3 towers, realizes five tower continuous pressure difference thermal couplings.Five tower continuous pressure difference thermal couplings comprise the first rectifying tower, Second distillation column, the 3rd rectifying tower, the 4th rectifying tower and the 5th rectifying tower, the pressure of five towers from low to high or from high to low, can series, parallel or onrelevant tower between tower, at the first rectifying tower tower top, condenser is set, and between the first rectifying tower and Second distillation column, between Second distillation column and the 3rd rectifying tower, between the 3rd rectifying tower and the 4th rectifying tower, a condensation reboiler is respectively set between the 4th rectifying tower and the 5th rectifying tower, the 5th rectifying tower arranges conventional reboiler.According to material feature and product requirement, each tower has dual-use function, can take off and gently can take off again heavily, and production process can be adjusted the function of each tower in real time.Because foreign matter content in chlorosilane purification is less, are all more than 95% trichlorosilanes, the changing function of Gu Ta is tower-coupled substantially without impact on five.Compared with simple coupling rectification technique, the continuous coupled energy-saving effect of five tower of the present invention is more obvious, and Energy Intensity Reduction 80% has solved the problem of purification process high energy consumption in polysilicon system, reduces enterprise's production cost, enhances the core competitiveness of enterprises.
According to a particular embodiment of the invention, the chlorosilane method of purification of the embodiment of the present invention, its low-temperature receiver adopts cheap recirculated water (temperature is 32 degree～42 degree).Thermal source adopts high-temperature-hot-water (150～130 degree), and this high-temperature-hot-water is in polysilicon system, to reduce the low-temperature receiver of operation.High-temperature water reduces in operation as low-temperature receiver in polysilicon system, after reduction operation, high-temperature water is elevated to 150 degree by 130 degree, and rectifying tower of the present invention just in time adopts reduction operation 150 degree high-temperature water out as thermal source, after purifying, high-temperature water is reduced to again 130 degree, and the former operation of returning is again as low-temperature receiver.Thus, whole polysilicon system is accomplished to heat rationally utilizes.
The chlorosilane method of purification of the above embodiment of the present invention has realized 5 tower continuous pressure difference thermal couplings, wherein, only has the first rectifying tower to need low-temperature receiver and the 5th rectifying tower to need thermal source, thus can energy-conservation 80%.
In addition, in existing more chlorosilane method of purification, for liquid heat at the bottom of preventing the tower of next stage overhead gas and upper level does not mate, prevent that overhead gas from can not total condensation be liquid after condensation reboiler, therefore increased auxiliary condenser, further condensation overhead gas, and the present invention finds rectifying tower tower top steam total condensation or excessively cold after the condensation of condensation reboiler, auxiliary condenser can be cancelled, reduce equipment configuration and pipeline configuration difficulty, expanded the use range of differential pressure heat coupled.
Compared with prior art, the chlorosilane method of purification of the embodiment of the present invention has the following advantages:
(1) only having the first rectifying tower that a conventional condenser is set needs low-temperature receiver, and only having the 5th rectifying tower that a conventional reboiler is set needs thermal source, and all the other rectifying tower all do not need low-temperature receiver and thermal source.
(2) the two the mean temperature difference of next stage rectifying tower tower top of the tower reactor of rectifying tower at different levels, coupling is with it reduced to 8～12 DEG C, by the tower top of same tower and the poor minimum 0.01～0.06MPa that is reduced to of tower base pressure, reduce the temperature difference differential pressure heat coupled has been counted to quantitative limitation.In the situation that ensureing that the first rectifying tower and last step rectifying tower are Cooling and Heat Source with recirculated water, high-temperature water respectively, the quantity of differential pressure heat coupled is expanded as to 5 towers by 2 or 3 towers.
(3) except the first rectifying tower, rectifying tower tower top vapor condensations at different levels are suitable with the required thermal load of previous stage tower bottom of rectifying tower vaporizing liquid to the required refrigeration duty of supercooled state, realize five tower continuous pressure difference thermal couplings, coupling heat exchange.The cooling and heating load of five tower continuous pressure difference thermal couplings reduces by 80%, and recirculated water, high-temperature water consumption reduce by 80%, realize the lowest energy consumption of whole rectification and purification method.The thermal source of the 5th rectifying tower adopts the heat-eliminating medium high-temperature water of reduction operation, realizes the exchange of purification process and reduction operation cooling and heating load, at utmost reduces polysilicon cost.
(4) each tower has dual-use function, can take off and gently can take off again heavily, and production process can be adjusted the function of each tower in real time.
(5) five tower relations, can be columns in seriess, can be also towers in parallel, can be also the differential pressure heat couplings between uncorrelated tower, have cancelled the restriction of conventional columns in series differential pressure heat coupling, have expanded the use range of differential pressure heat coupling.
(6) rectifying tower tower top steam total condensation or excessively cold after the condensation of condensation reboiler, auxiliary condenser can be cancelled, and has reduced equipment configuration and pipeline and has configured difficulty, has expanded the use range of differential pressure heat coupled, especially for the tower group of transformation project.
When (7) five towers adopt series system and pressure to reduce gradually, the tower tower reactor extraction of de-function light can utilize pressure reduction charging during to the charging of next stage rectifying tower, without column bottoms pump is set, reduce facility investment and power consumption, simultaneously because materials at bottom of tower mostly is saturated liquid, easily cause mercury vapour erosion or damage, increasing the stability of system.
Below with reference to specific embodiment, present invention is described, it should be noted that, these embodiment are only descriptive, and do not limit the present invention in any way.
Embodiment 1
The same Fig. 3 of technical process, tower inlet amount is 20m
3/ h, feed composition is: trichlorosilane mass content is 98%, silicon tetrachloride and dichloro-dihydro silicon are the metallic impurity trace such as 1%, B, P, Fe.
First raw material enters the first rectifying tower T1, and material flow is from the first rectifying tower T1 to the five rectifying tower T5, and wherein the first rectifying tower T1 to the five rectifying tower T5 pressure raise successively.
The tower top pressure of the first rectifying tower and temperature are respectively 0.25MPa(absolute pressure) and 54.9 DEG C, ensure that the tower top low-temperature receiver of the first rectifying tower (being the tower that pressure is minimum) is recirculated water; The tower reactor temperature of the 5th rectifying tower should be lower than 120 DEG C, ensure that the tower reactor thermal source of the 5th rectifying tower is high-temperature water, and the tower top tower base pressure of each tower is poor according to 0.02MPa simultaneously, and the coupling temperature difference is according to 10 DEG C, and the tower top tower sill strip part of each tower is in table 1.
The tower top tower bottom pressure temperature of the each rectifying tower of table 1.
| Title | Tower top pressure MPa | Tower top temperature DEG C | Tower reactor pressure MPa | Tower reactor temperature DEG C |
| The first rectifying tower | 0.25 | 54.9 | 0.27 | 63.6 |
| Second distillation column | 0.35 | 73 | 0.37 | 76.4 |
| The 3rd rectifying tower | 0.5 | 87.3 | 0.52 | 88.9 |
| The 4th rectifying tower | 0.65 | 98.5 | 0.67 | 99.9 |
| The 5th rectifying tower | 0.85 | 110.9 | 0.87 | 112 |
Ensure that by adjusting reflux ratio rectifying tower tower top vapor condensations at different levels are suitable with the required thermal load of previous stage tower bottom of rectifying tower vaporizing liquid to the required refrigeration duty of supercooled state, only have the first rectifying tower tower top condenser to need low-temperature receiver, the tower reactor reboiler of the 5th rectifying tower needs thermal source, between the first rectifying tower and Second distillation column, between Second distillation column and the 3rd rectifying tower, between the 3rd rectifying tower and the 4th rectifying tower, between the 4th rectifying tower and the 5th rectifying tower, a condensation reboiler is respectively set, do not need thermal source, and Second distillation column, the 3rd rectifying tower, the 4th rectifying tower, the auxiliary condenser of the 5th rectifying tower can be cancelled according to research above, therefore do not need low-temperature receiver yet, therefore five towers only have a tower to need low-temperature receiver, a tower needs thermal source, low-temperature receiver and thermal source Energy Intensity Reduction 80%.
After said process, refined product meets the requirement that electronic-grade polycrystalline silicon is produced.
Embodiment 2
The same Fig. 4 of technical process, tower inlet amount is 20m
3/ h, feed composition is: trichlorosilane mass content is 98%, silicon tetrachloride and dichloro-dihydro silicon are the metallic impurity trace such as 0.1%, B, P, Fe.
First raw material enters the 5th rectifying tower T5, and material flow is from the 5th rectifying tower T5 to the first rectifying tower T1, and wherein the 5th rectifying tower T5 to the first rectifying tower T1 pressure reduces successively.
The tower top pressure of the first rectifying tower and temperature are respectively 0.25MPa(absolute pressure) and 54.9 DEG C, ensure that the tower top low-temperature receiver of the first rectifying tower (being the tower that pressure is minimum) is recirculated water; The tower reactor temperature of the 5th rectifying tower should be lower than 120 DEG C, ensure that the tower reactor thermal source of the 5th rectifying tower is high-temperature water, and the tower top tower base pressure of each tower is poor according to 0.02MPa simultaneously, and the coupling temperature difference is according to 10 DEG C, and the tower top tower sill strip part of each tower is in table 2.
The tower top tower bottom pressure temperature of the each rectifying tower of table 2.
| Title | Tower top pressure MPa | Tower top temperature DEG C | Tower reactor pressure MPa | Tower reactor temperature DEG C |
| The 5th rectifying tower | 0.85 | 110.9 | 0.87 | 112 |
| The 4th rectifying tower | 0.65 | 98.5 | 0.67 | 99.9 |
| The 3rd rectifying tower | 0.5 | 87.3 | 0.52 | 88.9 |
| Second distillation column | 0.35 | 73 | 0.37 | 76.4 |
| The first rectifying tower | 0.25 | 54.9 | 0.27 | 63.6 |
Ensure that by adjusting reflux ratio rectifying tower tower top vapor condensations at different levels are suitable with the required thermal load of previous stage tower bottom of rectifying tower vaporizing liquid to the required refrigeration duty of supercooled state, only have the first rectifying tower tower top condenser to need low-temperature receiver, the tower reactor reboiler of the 5th rectifying tower needs thermal source, between the first rectifying tower and Second distillation column, between Second distillation column and the 3rd rectifying tower, between the 3rd rectifying tower and the 4th rectifying tower, between the 4th rectifying tower and the 5th rectifying tower, a condensation reboiler is respectively set, do not need thermal source, and Second distillation column, the 3rd rectifying tower, the 4th rectifying tower, the auxiliary condenser of the 5th rectifying tower can be cancelled according to research above, therefore do not need low-temperature receiver yet, therefore five towers only have a tower to need low-temperature receiver, a tower needs thermal source, low-temperature receiver and thermal source Energy Intensity Reduction 80%.
After said process, refined product meets the requirement that electronic-grade polycrystalline silicon is produced.
In the description of this specification sheets, the description of reference term " embodiment ", " some embodiment ", " example ", " concrete example " or " some examples " etc. means to be contained at least one embodiment of the present invention or example in conjunction with specific features, structure, material or the feature of this embodiment or example description.In this manual, the schematic statement of above-mentioned term is not necessarily referred to identical embodiment or example.And specific features, structure, material or the feature of description can be with suitable mode combination in any one or more embodiment or example.
Although illustrated and described embodiments of the invention above, be understandable that, above-described embodiment is exemplary, can not be interpreted as limitation of the present invention, those of ordinary skill in the art can change above-described embodiment within the scope of the invention in the situation that not departing from principle of the present invention and aim, amendment, replacement and modification.
Claims (10)
1. a chlorosilane method of purification, is characterized in that, comprising:
(1) in the first to the 5th rectifying tower, carry out accordingly respectively the first to the 5th rectification and purification by first to pentachloro-silane, to obtain respectively liquid at the bottom of the first to the 5th overhead vapours and the first to the 5th tower;
(2) described the first overhead vapours is carried out to condensation process in condenser, to obtain the first chlorosilane condensate liquid, and a part for described the first chlorosilane condensate liquid is back in described the first rectifying tower;
(3) part for liquid at the bottom of the described first to the 5th tower is carried out respectively accordingly in the first to the 5th reboiler to first to the 5th processing of boiling again, to obtain first to the 5th steam that boils again, and described first to the 5th steam that boils is again back to respectively in the described first to the 5th rectifying tower accordingly; And
(4) the described second to the 5th overhead vapours is back to respectively accordingly in step (3) successively for described first to fourth processing of boiling again, to obtain respectively second to pentachloro-silane phlegma, and described second part to pentachloro-silane phlegma is back to respectively in the described second to the 5th rectifying tower accordingly.
2. chlorosilane method of purification according to claim 1, is characterized in that, is 32～42 degrees Celsius for the temperature of the low-temperature receiver of described the first condensation process.
3. chlorosilane method of purification according to claim 1, is characterized in that, is the high-temperature water of 150 degrees Celsius for the described second thermal source that boils again processing, and described high-temperature water is to utilize the waste heat of polysilicon reduction operation to produce.
4. chlorosilane method of purification according to claim 1, it is characterized in that, for carrying out respectively the described first to the 5th rectifying tower of the described first to the 5th rectification and purification, the tower top temperature difference of the tower reactor of described the first rectifying tower and Second distillation column is 8-12 degree Celsius, the tower top temperature difference of the tower reactor of described Second distillation column and the 3rd rectifying tower is 8-12 degree Celsius, the tower top temperature difference of the tower reactor of described the 3rd rectifying tower and the 4th rectifying tower is 8-12 degree Celsius, and the tower top temperature difference of the tower reactor of described the 4th rectifying tower and the 5th rectifying tower is 8-12 degree Celsius.
5. chlorosilane method of purification according to claim 1, is characterized in that, in the described first to the 5th rectifying tower, the pressure reduction at the bottom of tower top and the tower of each rectifying tower is 0.01～0.06MPa.
6. chlorosilane method of purification according to claim 1, is characterized in that, the annexation between the described first to the 5th rectifying tower is divided into and is connected in series, is connected in parallel or onrelevant connection with the described first to the 5th opening for feed.
7. chlorosilane method of purification according to claim 1, is characterized in that, described second to pentachloro-silane be respectively a part for liquid at the bottom of the part of described first to fourth chlorosilane condensate liquid or first to fourth tower accordingly.
8. chlorosilane method of purification according to claim 7, is characterized in that, the mean pressure in the described first to the 5th rectifying tower is raise successively or reduce successively.
9. chlorosilane method of purification according to claim 1, is characterized in that, described first in pentachloro-silane at least one from different chlorosilane feedwaies.
10. chlorosilane method of purification according to claim 1, it is characterized in that, described first to pentachloro-silane be the hydrogenation condensation material that is selected from hydrogenation process in polysilicon system, dry method recovery process dry back rewinding, process the recovery tower raw material of the each group of low impurity that boils of tower height, further process at least one of rectifying tower raw material of hydrogenation condensation material and recovery tower product.
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| CN110282655A (en) * | 2019-08-08 | 2019-09-27 | 中国恩菲工程技术有限公司 | Titanium tetrachloride rectificating method |
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|---|---|---|---|---|
| CN101538045A (en) * | 2009-04-21 | 2009-09-23 | 天津大学 | Trichlorosilane differential pressure coupling rectification system and operation method thereof |
| CN101786630A (en) * | 2010-01-29 | 2010-07-28 | 天津大学 | Trichlorosilane three-tower differential pressure coupling energy-saving rectifying and purifying system and operating method |
| CN103449448A (en) * | 2013-08-23 | 2013-12-18 | 中国恩菲工程技术有限公司 | Equipment for purifying trichlorosilane |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101538045A (en) * | 2009-04-21 | 2009-09-23 | 天津大学 | Trichlorosilane differential pressure coupling rectification system and operation method thereof |
| CN101786630A (en) * | 2010-01-29 | 2010-07-28 | 天津大学 | Trichlorosilane three-tower differential pressure coupling energy-saving rectifying and purifying system and operating method |
| CN103449448A (en) * | 2013-08-23 | 2013-12-18 | 中国恩菲工程技术有限公司 | Equipment for purifying trichlorosilane |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110282655A (en) * | 2019-08-08 | 2019-09-27 | 中国恩菲工程技术有限公司 | Titanium tetrachloride rectificating method |
| CN110282655B (en) * | 2019-08-08 | 2021-12-03 | 中国恩菲工程技术有限公司 | Titanium tetrachloride rectification method |
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