CN104003396A

CN104003396A - Method and system for preparing polycrystalline silicon and method and system for purifying trichlorosilane

Info

Publication number: CN104003396A
Application number: CN201410260437.9A
Authority: CN
Inventors: 李锋; 王利强; 张艳春; 濮希杰; 张晓峰; 高阳; 隋永亮; 庄志远
Original assignee: State's Electricity Inner Mongol Jing Yang Ltd Energy Co
Current assignee: State's Electricity Inner Mongol Jing Yang Ltd Energy Co
Priority date: 2014-06-12
Filing date: 2014-06-12
Publication date: 2014-08-27
Anticipated expiration: 2034-06-12
Also published as: CN104003396B

Abstract

The invention provides a system and method for preparing polycrystalline silicon and a method and system for purifying trichlorosilane. The method for preparing the polycrystalline silicon comprises the steps that firstly, hydrogen and trichlorosilane are respectively heated through hot water so that cooled hot water and heated hydrogen and trichlorosilane can be obtained; secondly, reduction reaction is carried out on the heated hydrogen and the heated trichlorosilane in a reduction furnace so that the polycrystalline silicon and the reduction tail gas can be obtained, and water cooling is carried out on the reduction furnace to obtain first hot water; thirdly, the cooled hot water is heated through the reduction tail gas to obtain second hot water; fourthly, first hot water and second hot water are mixed to obtain reduction workshop section hot water serving as a heat source of a rectifying tower so that the pure trichlorosilane can be extracted and purification workshop section returning water can be obtained, wherein the temperature of the first hot water and the temperature of the second hot water range from 145 DEG C to 150 DEG C. By means of the method, the water resource and the heat energy can be recycled, and the energy consumption can be obviously saved.

Description

Prepare the method and system of polysilicon and the method and system of purify trichlorosilane

Technical field

The present invention relates to field polysilicon, particularly, the present invention relates to prepare the method and system of polysilicon and the method and system of purify trichlorosilane.

Background technology

In existing production of polysilicon, especially in the preparation of polysilicon and the purifying technique of trichlorosilane, all need a large amount of water resourcess, thermal source and low-temperature receiver, cause the production of polysilicon to have the defect that energy consumption is good, cost is high.Therefore, existing relevant production of polysilicon technique still needs further improvement.

Summary of the invention

The present invention is intended to solve at least to a certain extent one of technical problem in correlation technique.For this reason, one object of the present invention is to propose to prepare the method and system of polysilicon and the method and system of purify trichlorosilane, utilize above-mentioned two kinds of method and systems to mate with thermal source in purify trichlorosilane preparing the reduction furnace water coolant and the heating raw materials water that use in polysilicon, and then make full use of water resources and save energy consumption.

According to an aspect of the present invention, the method for preparing polysilicon of the embodiment of the present invention comprises:

(1) utilize hot water respectively hydrogen and trichlorosilane to be heated, to obtain hydrogen and trichlorosilane through overcooled hot water and process heat treated,

(2) in reduction furnace, there is reduction reaction more in described hydrogen and the trichlorosilane through heat treated that makes to obtain in step (1), to obtain polysilicon and reduction tail gas, wherein, in reduction reaction process, described reduction furnace is carried out to water-cooled, and obtain the first hot water;

(3) utilize described reduction tail gas to heat through overcooled hot water resulting in step (1), to obtain the second hot water; And

(4) described the first hot water and described the second hot water are mixed, to obtain reducing workshop section's hot water, and the thermal source using described reduction workshop section hot water as rectifying tower is for purify trichlorosilane, so that the workshop section that obtains purifying returns to water;

Wherein, the temperature of described the first hot water and described the second hot water is respectively independently within the scope of 145～155 degrees Celsius.

In addition, the method for preparing polysilicon according to the above embodiment of the present invention can also have following additional technical characterictic:

In some embodiments of the invention, the hot water temperature who adopts in step (1) is 130 degrees Celsius, adopts the water of 130 degrees Celsius respectively described water-cooled to be carried out in the chassis of described reduction furnace and chuck in step (2).

In some embodiments of the invention, described is 110 degrees Celsius through the hydrogen of heat treated and the temperature of trichlorosilane, and by before the resulting described hydrogen through heat treated and trichlorosilane are incorporated into described reduction furnace in step (1), adopt in advance described reduction tail gas to be preheated to 180 degrees Celsius.

In some embodiments of the invention, in above-mentioned steps (4), comprising:

Supplementary feed and described reduction workshop section hot water are mixed, and resulting mixing water is heated to after 150 degrees Celsius to the thermal source as rectifying tower.

In some embodiments of the invention, described supplementary feed obtains through the following steps:

(4-1) thermal source using a part for described reduction workshop section hot water as rectifying tower is for purify trichlorosilane, and the workshop section that simultaneously obtains purifying returns to water, and

(4-2) second section of described reduction workshop section hot water being carried out after water-cooled mixing with at least a portion that is selected from described third part of reducing workshop section's hot water and described purification workshop section and returns water, is the described supplementary feed of 130 degrees Celsius to obtain temperature.

In some embodiments of the invention, in step (4), further comprise

(4-1) thermal source using the first part of described reduction workshop section hot water as rectifying tower is for purify trichlorosilane, and the workshop section that simultaneously obtains purifying returns to water;

(4-2) second section of described reduction workshop section hot water being carried out after water-cooled mixing with at least a portion that is selected from described third part of reducing workshop section's hot water and described purification workshop section and returns water, is the water of 130 degrees Celsius to obtain temperature;

(4-3) water that is 130 degrees Celsius using the temperature obtaining in step (4-2) is heated to 150 degrees Celsius of thermals source as rectifying tower for purify trichlorosilane.

According to a further aspect in the invention, the method for the purify trichlorosilane of the embodiment of the present invention, described trichlorosilane contains dichloro-dihydro silicon and tetrachloro hydrogen silicon, it is characterized in that, and described method comprises:

(1) described trichlorosilane is carried out to the first rectification process, so that gas and the first liquid heavy constituent after acquisition trichlorosilane, the first phlegma, the first condensation, wherein, after described the first condensation, liquid contains dichloro-dihydro silicon and trichlorosilane, and in described the first liquid state, component contains tetrachloro hydrogen silicon and trichlorosilane;

(2) described the first liquid heavy constituent is carried out to the second rectification process, to obtain liquid after the second condensation, the second condensation later stage and the second liquid heavy constituent, wherein, after described the second condensation, liquid contains silicon tetrachloride;

(3) by gas after gas after described the first condensation and described the second condensation one of at least carry out condensation process, to obtain after the 3rd condensation gas after liquid and the 3rd condensation; And

(4) liquid after liquid after described the first condensation and described the 3rd condensation one of at least carried out to the 3rd rectification process, to obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation, wherein, after described the 4th condensation, liquid contains dichloro-dihydro silicon, described the 3rd liquid heavy constituent contains trichlorosilane

Wherein, the thermal source one of at least of described the first rectification process, the second rectification process, the 3rd rectification process is reduction workshop section hot water, and described reduction workshop section hot water is by following acquisition:

(2) make resulting described hydrogen and trichlorosilane through heat treated in step (1) that reduction reaction occur in reduction furnace, to obtain polysilicon and reduction furnace tail gas, wherein, in reduction reaction process, described reduction furnace is carried out to water-cooled, and obtain the first hot water;

(4) described the first hot water and described the second hot water are mixed, to obtain reducing workshop section's hot water, wherein, the temperature of described the first hot water and described the second hot water is respectively independently in the scope of 145～155 degrees Celsius.

In accordance with a further aspect of the present invention, the system of preparing polysilicon of the embodiment of the present invention, comprising:

Hydrogen heating unit and trichlorosilane heating unit, described hydrogen heating unit and trichlorosilane add thermal utilization hot water and respectively hydrogen and trichlorosilane are heated, to obtain hydrogen and trichlorosilane through overcooled hot water and process heat treated;

Reduction furnace, described reduction furnace is connected with trichlorosilane heating unit with described hydrogen heating unit respectively, for making described hydrogen and trichlorosilane through heat treated that reduction reaction occur in reduction furnace, to obtain polysilicon and reduction furnace tail gas, wherein, described reduction furnace has water-cooled assembly, and described reduction furnace is carried out to water-cooled, and obtains the first hot water:

Gas-liquid heat exchanger, described gas-liquid exchange device is connected with reduction furnace with described hydrogen heating unit, trichlorosilane heating unit respectively, for utilizing described reduction tail gas to heat through overcooled hot water described, to obtain the second hot water; And

Hot water mixing device, described hot water mixing device is connected with described gas-liquid heat exchanger with described reduction furnace respectively, for described the first hot water and described the second hot water are mixed, to obtain reducing workshop section's hot water;

Trichlorosilane purification devices, described trichlorosilane purification devices comprises rectifying tower, and described rectifying tower is connected with described hot water mixing device, the thermal source using described reduction workshop section hot water as rectifying tower, returns to water for use in the purify trichlorosilane workshop section that obtains purifying; Described trichlorosilane purification devices is connected with reduction furnace with described hydrogen heating unit, trichlorosilane heating unit, to utilize described pure workshop section to return to water respectively to described hydrogen with trichlorosilane heats and described reduction furnace is carried out to water-cooled.

In addition, the system of preparing polysilicon according to the above embodiment of the present invention can also have following additional technical characterictic:

In some embodiments of the invention, the above-mentioned system of preparing polysilicon further comprises:

Gas gas heat exchanger, described gas gas heat exchanger is connected with described hydrogen heating unit, trichlorosilane heating unit, reduction furnace and gas-liquid heat exchanger respectively, described is 110 degrees Celsius through the hydrogen of heat treated and the temperature of trichlorosilane, to obtain, before described hydrogen through heat treated and trichlorosilane be incorporated into described reduction furnace, adopt in advance described reduction furnace to be preheated to 180 degrees Celsius.

In some embodiments of the invention, further comprise:

Supplementary feed device, described supplementary feed device is connected with described hot water mixing device, to add supplementary feed in described reduction workshop section hot water.

Heating unit, described heating unit is connected with described hot water mixing device, so that after adding reduction workshop section hot water heating to 150 after described supplementary feed degree Celsius and as the thermal source of rectifying tower.

In some embodiments of the invention, further comprise:

Refrigerating unit, described refrigerating unit is connected with device for supplying with described hot water mixing device, so that the thermal source using the first part of described reduction workshop section hot water as rectifying tower is for purify trichlorosilane, the workshop section that simultaneously obtains purifying returns to water; And the second section of described reduction workshop section hot water is carried out after cooling returning to one of at least mixing of water with being selected from described third part of reducing workshop section's hot water and described purification workshop section, to obtain temperature, be the described supplementary feed of 130 degrees Celsius.

In some embodiments of the invention, described refrigerating unit, described refrigerating unit is connected with described hot water mixing device, hydrogen heating unit, trichlorosilane heating unit and reduction furnace, so that the thermal source using the first part of described reduction workshop section hot water as rectifying tower is for purify trichlorosilane, the workshop section that simultaneously obtains purifying returns to water; The second section of described reduction workshop section hot water is carried out after cooling returning to one of at least mixing of water with being selected from described third part of reducing workshop section's hot water and described purification workshop section, is the water of 130 degrees Celsius to obtain temperature; And by resulting temperature, be that the water of 130 degrees Celsius is for respectively to described hydrogen with trichlorosilane heats and described reduction furnace is carried out to water-cooled.

In some embodiments of the invention, described supplementary feed device further comprises:

Constant pressure tank, described Constant pressure tank is connected with described hot water mixing device;

Constant pressure tank;

Constant pressure pump, described constant pressure pump is arranged between described Constant pressure tank and described constant pressure tank;

Tensimeter, described tensimeter is connected with described Constant pressure tank and is arranged on a side of the water outlet of proximity thermal water mixing device.

According to a further aspect of the invention, the system of the purify trichlorosilane of the embodiment of the present invention, described trichlorosilane contains dichloro-dihydro silicon and silicon tetrachloride, and described system comprises:

The first rectification cell, described the first rectification cell is for carrying out the first rectification process to described trichlorosilane, to obtain gas and the first liquid heavy constituent after liquid after trichlorosilane, the first condensation, the first condensation, wherein, after described the first condensation, liquid contains dichloro-dihydro silicon and trichlorosilane, and described the first liquid heavy constituent contains silicon tetrachloride and trichlorosilane;

The second rectifier unit, described the second rectifier unit is connected with described the first rectification cell, for described the first liquid heavy constituent is carried out to the second rectification process, to obtain gas and the second liquid heavy constituent after liquid after the second condensation, the second condensation, wherein, after described the second condensation, liquid contains silicon tetrachloride;

Condensing works, described condensing works is connected with described the second rectifier unit with described the first rectification cell, for to gas after gas after described the first condensation and described the second condensation one of at least carry out condensation process, to obtain after the 3rd condensation gas after liquid and the 3rd condensation; And

The 3rd rectifier unit, described the 3rd rectifier unit is connected with described condensing works with described the first rectification cell, for liquid after liquid after described the first condensation and described the 3rd condensation one of at least carried out to the 3rd rectification process, to obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation, wherein, after described the 4th condensation, liquid contains dichloro-dihydro silicon, and described the 3rd liquid heavy constituent contains trichlorosilane;

Wherein, the thermal source one of at least of described the first rectification cell, the second rectifier unit, the 3rd rectifier unit is reduction workshop section hot water, and described reduction workshop section hot water is from the system of preparing polysilicon, and described polysilicon system comprises:

Hot water mixing device, described hot water mixing device is connected with described gas-liquid heat exchanger with described reduction furnace respectively, for described the first hot water and described the second hot water are mixed, to obtain reducing workshop section's hot water.

Accompanying drawing explanation

Fig. 1 is the schema of the method for purify trichlorosilane according to an embodiment of the invention.

Fig. 2 is the structural representation of preparing according to an embodiment of the invention the system of polysilicon.

Fig. 3 is the structural representation of preparing in accordance with another embodiment of the present invention the system of polysilicon.

Fig. 4 is the structural representation of the system of preparing polysilicon of another embodiment according to the present invention.

Fig. 5 is the structural representation of the system of purify trichlorosilane according to an embodiment of the invention.

Fig. 6 is the method flow diagram of preparing according to an embodiment of the invention polysilicon.

Fig. 7 is the method flow diagram of preparing according to an embodiment of the invention polysilicon.

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.Below by the embodiment being described with reference to the drawings, be exemplary, be intended to for explaining the present invention, and can not be interpreted as limitation of the present invention.

The method of preparing according to an embodiment of the invention polysilicon specifically comprises the following steps:

Commonly in the production of polysilicon, need a large amount of water resourcess, the hot water for example raw hydrogen and trichlorosilane being heated, reduction furnace is carried out cooling water coolant and needs a large amount of thermals source to the trichlorosilane purification of boiling again, therefore the present inventor finds, if by between water in the preparation process of polysilicon and the required water of the purification of trichlorosilane by the recycle of mating of heat and the water yield, not only a large amount of water resourcess can be saved, extra cooling and heating energy consumption can also be saved simultaneously.But the number of opening or moving due to reduction furnace can change constantly, and the number of purify trichlorosilane rectifying tower used is unstable, be difficult to meet institute's water requirement and water temperature in two techniques, therefore the water in two techniques recycled to tool great difficulty.

According to an embodiment of the invention, the hot water temperature who adopts in above-mentioned steps (1) is 130 degrees Celsius, adopts the water of 130 degrees Celsius respectively described water-cooled to be carried out in the chassis of reduction furnace and chuck in step (2).That is to say that preparing the needed water temp of polysilicon all can be 130 degrees Celsius, and the temperature of the reduction workshop section hot water obtaining after heating and water-cooled is 145～155 degrees Celsius, and the hot water of this temperature can be further used as rectifying tower thermal source for purify trichlorosilane.Contriver also finds, the temperature that the purification workshop section obtaining after heating rectifying tower returns to water is about 130 degrees Celsius, is just being used on the heat treated of the cooling and raw material of the reduction furnace of reduction reaction, thereby reached hot water temperature's coupling.The present inventor has found above-mentioned two temperature just, for rectifying tower heating, with hot water, can be about 150 degrees Celsius, to rectifying tower temperature after heating near 130 degrees Celsius, further return for the preparation of polysilicon, utilize reduction tail gas further the water of reduction workshop section to be heated and finally obtains 150 degrees Celsius of water again for purify trichlorosilane, and then reach the coupling of water temp.

According to a particular embodiment of the invention, through the hydrogen of heat treated and the temperature of trichlorosilane, it is 110 degrees Celsius, and by before the resulting hydrogen through heat treated and trichlorosilane are incorporated into reduction furnace in step (1), adopt in advance reduction tail gas to be preheated to 180 degrees Celsius.Can make full use of thus the heat energy of reduction tail gas, improve the efficiency of reduction reaction.According to a particular embodiment of the invention, after first reduction tail gas heat hydrogen and trichlorosilane, further to above-mentioned carrying out preheating and then obtaining the hot water that temperature is about 150 degrees Celsius through overcooled hot water after hydrogen and trichlorosilane are heated.The heat energy of the present invention by making full use of reduction tail gas, by the hot water heating of reduction workshop section to being about 150 degrees Celsius, and then is applicable to purify trichlorosilane thus, for preparing polysilicon process water cycle, provides guarantee.

According to a particular embodiment of the invention, in above-mentioned steps (4), can further include: supplementary feed and reduction workshop section hot water are mixed, and resulting mixing water is heated to after 150 degrees Celsius to the thermal source as rectifying tower.In the time of can guaranteeing that thus the water yield when reduction workshop section hot water can not meet in purifying technique institute's water consumption, the water yield lacking to supply in reduction workshop section hot water in time.According to a particular embodiment of the invention, can adopt tensimeter to monitor constantly the pressure of the water between reduction workshop section's hot water and purification workshop section, and then judge that whether the water yield is not enough.Simultaneously tensimeter with determine power pump and constant pressure tank and be connected, and then according to tensimeter pressure changing supplementary feed in trend is reduced workshop section's hot water.Can avoid thus, because service discharge deficiency causes fluctuating greatly for the rectifying tower of purify trichlorosilane, affecting quality product.

According to a particular embodiment of the invention, first above-mentioned supplementary feed obtains through the following steps:

(4-1) thermal source using a part for reduction workshop section hot water as rectifying tower is for purify trichlorosilane, and the workshop section that simultaneously obtains purifying returns to water, and

According to a particular embodiment of the invention, when hot water amount described in the amount of reduction workshop section hot water has exceeded purify trichlorosilane, the method for preparing polysilicon of the above embodiment of the present invention can also reach the coupling of the water yield through the following steps.According to a particular embodiment of the invention, in above-mentioned steps (4), can further include:

(4-1) thermal source using the first part of reduction workshop section hot water as rectifying tower is for purify trichlorosilane, and the workshop section that simultaneously obtains purifying returns to water;

(4-2) second section of reduction workshop section hot water being carried out after water-cooled reducing the third part of workshop section's hot water and at least a portion that purification workshop section returns to water and mixing with being selected from, is the water of 130 degrees Celsius to obtain temperature.

Thus, by obtaining the water of 130 degrees Celsius after the water of redundance is lowered the temperature, again with purification workshop section, return to water and return to and heating raw material cooling for reduction furnace.And the present invention by the sub-fraction of unnecessary reduction workshop section hot water is carried out cooling after and another part be mixed to get the water of 130 degrees Celsius, and then can save cooling energy consumption.

By adopting the method for preparing polysilicon of the above embodiment of the present invention, when the reduction hot water amount of workshop section is identical with the purification workshop section water yield, only need in advance this water be heated to after 130 degrees Celsius, the heat that only need to make full use of reduction tail gas in follow-up working cycle can arrive whole process water circulation, without extra heat, cold and extra supplementary feed.Can significantly save the water yield and energy consumption thus.

By adopting the method for preparing polysilicon of the above embodiment of the present invention, when the reduction workshop section hot water water yield is less than the purification workshop section water yield, can change after automatically adding supplementary feed in reduction workshop section hot water and again be heated to approximately 150 degrees Celsius by monitor force, and then avoid affecting the quality of purification workshop section trichlorosilane.

By adopting the method for preparing polysilicon of the above embodiment of the present invention, when the reduction workshop section water yield is when with the purification workshop section water yield, by unnecessary hot water is divided into two portions, a part is wherein carried out cooling, and then after making unnecessary hot water temperature be down to 130 degrees Celsius again for reducing workshop section.

According to a further aspect in the invention, the present invention proposes a kind of method of purify trichlorosilane, in described trichlorosilane, contain dichloro-dihydro silicon and tetrachloro hydrogen silicon.According to the method for the purify trichlorosilane of the embodiment of the present invention, comprise:

Below with reference to Fig. 1, describe the method for the purify trichlorosilane of the above embodiment of the present invention in detail.

S100: the first rectification process

According to embodiments of the invention, trichlorosilane carries out the first rectification process, thereby can obtain respectively gas and the first liquid heavy constituent after liquid after trichlorosilane, the first condensation, the first condensation.According to embodiments of the invention, after the first condensation, liquid can contain dichloro-dihydro silicon and trichlorosilane, and the first liquid heavy constituent can contain silicon tetrachloride and trichlorosilane.According to embodiments of the invention, can adopt the rectifying tower of a plurality of series connection to carry out the first rectification process, according to a particular embodiment of the invention, can adopt the rectifying tower of five series connection to carry out the first rectification process.According to concrete example of the present invention, the rectifying tower of five series connection comprises the first to the 5th rectifying tower, and each includes: liquid outlet at the bottom of tower body, overhead gas outlet, tower, opening for feed, condensation separator, well heater, wherein, in tower body, limit rectifying space, be suitable for the material in rectifying space to carry out rectification process, thereby can obtain respectively liquid and overhead gas at the bottom of tower; Overhead gas outlet is arranged on the top of tower body, is suitable for exporting overhead gas; At the bottom of tower, liquid outlet is arranged on the bottom of tower body, is suitable for exporting liquid at the bottom of tower; Opening for feed is arranged on tower body, is suitable for introducing the material for the treatment of rectifying in rectifying space; Condensation separator is connected with overhead gas outlet, is suitable for overhead gas to carry out condensation separation processing, thereby can obtains condensing air and phlegma; Well heater is connected with tower body, is suitable for rectifying space to heat.

Concrete, by well heater, heat treated is carried out in the first rectifying tower rectifying space, then by opening for feed, in rectifying space, add trichlorosilane (coarse fodder that contains 85% left and right trichlorosilane), the light constituent that makes to contain a large amount of dichloro-dihydro silicon and the mixed gas of lower boiling impurity are discharged from top gas outlet, then mixed gas is carried out to condensation separation processing through condensation separator, thereby after the first rectifying tower condensation that can obtain respectively containing dichloro-dihydro silicon and trichlorosilane liquid and the first rectifying tower condensation after gas, and heavy constituent and high boiling impurity as the first rectifying tower at the bottom of liquid from furnace bottom liquid outlet, discharge.According to embodiments of the invention, the first rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.245MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.298MPaG, and service temperature is 77～79 ℃, and reflux ratio is 133.5.At the bottom of the first rectifying tower, liquid carries out rectification process as the rectifying material for the treatment of of Second distillation column, most of heavy constituent silicon tetrachloride and high-boiling-point impurity can be removed, thereby liquid at the bottom of gas and Second distillation column tower can be obtained respectively after liquid after Second distillation column condensation, Second distillation column condensation.According to embodiments of the invention, Second distillation column can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.243MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.297MPaG, and service temperature is 84～87 ℃, and reflux ratio is 14.5.After Second distillation column condensation, liquid carries out rectification process as the rectifying material for the treatment of of the 3rd rectifying tower, can further remove light constituent impurity residual in material, make light constituent foreign matter content in material reach the requirement of electronic-grade trichlorosilane, thereby can obtain respectively after liquid after the 3rd rectifying tower condensation, the 3rd rectifying tower condensation liquid at the bottom of gas and the 3rd rectifying tower.According to embodiments of the invention, the 3rd rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.25MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.304MPaG, and service temperature is 77～79 ℃, and reflux ratio is 128.5.At the bottom of the 3rd rectifying tower, liquid treats that as the 4th rectifying tower rectifying material carries out rectification process, the heavy constituent impurity of the middle remnants in material can be removed, thereby liquid at the bottom of gas and the 4th rectifying tower can be obtained respectively after liquid after the 4th rectifying tower condensation, the 4th rectifying tower condensation.According to embodiments of the invention, the 4th rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is that 32nd～55 blocks of column plates go out, and tower top working pressure is 0.250MPaG, service temperature is 71～73 ℃, tower reactor working pressure 0.303MPaG is, service temperature is 77～79 ℃, and reflux ratio is 18.After the 4th rectifying tower condensation, liquid carries out rectification process as the rectifying material for the treatment of of the 5th rectifying tower, remaining heavy constituent impurity can be further removed in material, thereby liquid at the bottom of gas and the 5th rectifying tower can be obtained after liquid after the 5th rectifying tower condensation, the 5th rectifying tower condensation.According to embodiments of the invention, the 5th rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.246MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.298MPaG, and service temperature is 77～79 ℃, and reflux ratio is 20.

According to embodiments of the invention, by first to one of being at least connected with the opening for feed of the first rectifying tower of liquid outlet at the bottom of the tower of the 5th rectifying tower, to make liquid at the bottom of tower that the second to the 5th rectifying tower one of at least discharges treat the use of rectifying material as the first rectifying tower.For example, can return as the treating rectifying material of the first rectifying tower and use using the 4th to liquid at the bottom of the tower of the 5th rectifying tower.Particularly, at the bottom of tower, in liquid, contain the trichlorosilane of part, by liquid at the bottom of tower is returned and proceeds rectification process, can significantly improve the utilization ratio of material.

S200: the second rectification process

According to embodiments of the invention, the liquid heavy constituent of above gained first is carried out to the second rectification process, thereby can obtain gas and the second liquid heavy constituent after liquid after the second condensation, the second condensation.According to embodiments of the invention, after the second condensation, in liquid, contain silicon tetrachloride.According to a particular embodiment of the invention, liquid at the bottom of the first to the 5th rectifying tower tower one of at least can be carried out to the second rectification process, for example, liquid at the bottom of Second distillation column tower can be carried out to the second rectification process as the first liquid heavy constituent.According to embodiments of the invention, the second liquid restructuring is divided into waste liquid, can directly be delivered to liquid waste disposal operation and process.Contriver finds, contains silicon tetrachloride and a large amount of heavy constituent impurity at the bottom of Second distillation column tower in liquid, can effectively remove most heavy constituent impurity, thereby can obtain finished product silicon tetrachloride by carrying out the second rectification process.Particularly, the second rectification process device can be high-efficiency guide sieve-plate tower, tower internal diameter is 2200mm, stage number is 60, and opening for feed is 25th～45 blocks of column plates, and tower top working pressure is 0.213MPaG, service temperature is 89～92 ℃, tower reactor working pressure is 0.223MPaG, and service temperature is 128～131 ℃, and reflux ratio is 4.5.

S300: condensation process

According to embodiments of the invention, by gas after gas and the second condensation after above gained the first condensation one of at least carry out condensation process, thereby can obtain after the 3rd condensation gas after liquid and the 3rd condensation.According to embodiments of the invention, the condition of condensation process is also not particularly limited, and according to a particular embodiment of the invention, condensation process can be to carry out under-40～-38 degrees Celsius and the pressure condition that is 0.1～0.15MPaG in temperature.Contriver finds, the condensation process of carrying out under this condition can obviously improve after condensation the separation efficiency of liquid after gas and condensation.According to embodiments of the invention, after the condensation one of at least producing that can the using first to the 5th rectifying tower, gas gas after the first condensation carries out condensation process.Contriver finds, contains a large amount of dichloro-dihydro silicon and a small amount of trichlorosilane after the first condensation after gas and the second condensation in gas, is carried out carrying out subsequent disposal after condensation process again, can significantly improve the utilization ratio of material, can reduce exhaust emissions amount simultaneously.According to embodiments of the invention, after the 3rd condensation, in gas, contain noncondensable gas, can directly be sent to off gas treatment operation and process.According to a particular embodiment of the invention, the device of condensation process can be double-tube sheet shell and tube heat exchanger, heat exchanger tube pass fluid is gas after each tower condensation, shell-side fluid is-38 ℃ of chilled brines, in upper cover, there is a pass partition, dividing plate one side has gas admission port after each tower condensation, and opposite side has noncondensable gas discharge outlet, and lower cover has a condensate discharge mouth.

S400: the 3rd rectification process

According to embodiments of the invention, by liquid after liquid after the first condensation and the 3rd condensation one of at least carry out the 3rd rectification process, thereby can obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation.According to a particular embodiment of the invention, after the 4th condensation, in liquid, contain dichloro-dihydro silicon, the 3rd liquid heavy constituent contains trichlorosilane.According to embodiments of the invention, after the condensation can the using first to the 5th rectifying tower one of at least producing, liquid liquid after the first condensation carries out the 3rd rectification process.For example, after the condensation that, the first and the 3rd rectifying tower can be produced, after liquid and the 3rd condensation, liquid carries out the 3rd rectification process.Contriver finds, after the first and the 3rd rectifying tower condensation, in liquid, contain more than 99% trichlorosilane, the dichloro-dihydro silicon less than 1% and a large amount of light constituent impurity (as the compound of boron), by the 3rd rectification process, can remove most of dichloro-dihydro silicon and the lower-boiling impurity in light constituent material, and can reach more than 99.99% through trichlorosilane content in the 3rd rectification process gained the 3rd liquid heavy constituent.According to embodiments of the invention, the 3rd rectifier unit can be high-efficiency guide sieve-plate tower, tower internal diameter is 1200mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.248MPaG, service temperature is 55～58 ℃, tower reactor working pressure is 0.298MPaG, and service temperature is 77～79 ℃, and reflux ratio is 47.

According to the method for the purify trichlorosilane of the embodiment of the present invention, can prepare the required trichlorosilane of electronic-grade polycrystalline silicon, and by gas centralized recovery after gas and the second condensation after the condensation that the first to the 5th rectifying tower is produced, and gas after condensation is concentrated and carried out condensation process, can obviously reduce the consumption of cold and the discharge of tail gas, liquid at the bottom of Second distillation column tower is proceeded to rectification process simultaneously, can obtain silicon tetrachloride product, in addition, after the condensation that the first to the 5th rectifying tower one of is at least produced, after liquid and the 3rd condensation, liquid is proceeded rectification process, can effectively trichlorosilane wherein be carried out separated with dichloro-dihydro silicon.

According to a particular embodiment of the invention, above-mentioned the first to the 5th rectifying tower for the first rectification process and can adopt reduction workshop section hot water for the rectifying tower of the second rectification process and the 3rd rectification process thermal source one of at least, and reduction workshop section hot water is by following acquisition:

(2) make resulting hydrogen and trichlorosilane through heat treated in step (1) that reduction reaction occur in reduction furnace, to obtain polysilicon and reduction furnace tail gas, wherein, in reduction reaction process, reduction furnace is carried out to water-cooled, and obtain the first hot water;

(3) utilize reduction tail gas to heat through overcooled hot water resulting in step (1), to obtain the second hot water; And

(4) the first hot water and described the second hot water are mixed, to obtain reducing workshop section's hot water, wherein, the temperature of the first hot water and described the second hot water is respectively independently in the scope of 145～155 degrees Celsius.

Thus the present invention by the reduction workshop section hot water that produces in preparing polysilicon as the thermal source of rectifying tower for purify trichlorosilane, and the present invention makes full use of reduction tail gas heat quantity, and to make the temperature of the reduction workshop section hot water that finally obtains be 145～155 degrees Celsius, and then can meet the requirement of purify trichlorosilane technique to water temp.The method of the purify trichlorosilane of the above embodiment of the present invention adopts reduction workshop section hot water to heat rectifying tower, can save a large amount of water resourcess and heat energy.Especially the temperature of hot water of workshop section of reducing is 145～155 degrees Celsius, can effectively maintain the stability of the rectifying tower adopting in purify trichlorosilane, and then guarantee that quality product is unaffected.In addition, the beneficial effect in the method for preparing polysilicon according to the above embodiment of the present invention is equally applicable to the method for the purify trichlorosilane of above-described embodiment, does not repeat them here.

According to a further aspect of the invention, the invention allows for a kind of system of preparing polysilicon, below with reference to Fig. 2, describe the system of preparing polysilicon of the embodiment of the present invention in detail.

As shown in Figure 2, the system of preparing polysilicon of the embodiment of the present invention comprises: hydrogen heating unit 100, trichlorosilane heating unit 200, reduction furnace 300, gas-liquid heat exchanger 400, hot water mixing device 500 and trichlorosilane purification devices 600.

Wherein, hydrogen heating unit 100 and trichlorosilane heating unit 200 utilize hot water respectively hydrogen and trichlorosilane to be heated, to obtain hydrogen and trichlorosilane through overcooled hot water and process heat treated;

Reduction furnace 300 is connected with trichlorosilane heating unit 200 with hydrogen heating unit 100 respectively, for making through the hydrogen of heat treated and trichlorosilane in the interior generation reduction reaction of reduction furnace 300, to obtain polysilicon and reduction furnace tail gas, wherein, reduction furnace has water-cooled assembly, reduction furnace is carried out to water-cooled, and obtain the first hot water;

Gas-liquid heat exchanger 400 is connected with hydrogen heating unit 100, trichlorosilane heating unit 200 and reduction furnace 300 respectively, for utilizing reduction tail gas to heating through overcooled hot water, to obtain the second hot water; And

Hot water mixing device 500 is connected with gas-liquid heat exchanger 400 with reduction furnace 300 respectively, for the first hot water and the second hot water are mixed, to obtain reducing workshop section's hot water;

Trichlorosilane purification devices 600 comprises rectifying tower, and rectifying tower is connected with hot water mixing device 500, will reduction workshop section hot water as the thermal source of rectifying tower, for use in the purify trichlorosilane workshop section that obtains purifying, return to water; Trichlorosilane purification devices 600 is connected with hydrogen heating unit 100, trichlorosilane heating unit 200 and reduction furnace 300, to utilize pure workshop section to return to water respectively to hydrogen with trichlorosilane heats and reduction furnace 300 is carried out to water-cooled.

Thus, the present invention is by designing the above-mentioned system of preparing polysilicon, can using the reduction workshop section hot water finally obtaining for trichlorosilane purification devices 600 the thermal source purify trichlorosilane as rectifying tower.Can significantly save water resources and energy consumption thus.In addition, by recycle and the heat energy that adopts the above-mentioned system of preparing polysilicon can realize water resources, mate.Particularly, the above-mentioned system of preparing polysilicon is to implement and circulation and the heat energy of realizing water resources mates by following manner.First hydrogen heating unit 100, trichlorosilane heating unit 200, reduction furnace 300 adopts respectively the water of 130 degrees Celsius carry out reduction reaction heating raw materials and carry out cooling to reduction furnace, in the interior temperature that can obtain of hot water mixing device 500, be finally the reduction workshop section hot water of 150 degrees Celsius, further the reduction workshop section hot water of 150 degrees Celsius is used for to trichlorosilane purification devices 600 as the thermal source purify trichlorosilane of rectifying tower, and to obtain temperature be that the purification workshop section of 130 degrees Celsius returns to water, and returning to water, the purification workshop section that this temperature is 130 degrees Celsius just in time can return to hydrogen heating unit 100, trichlorosilane heating unit 200, in reduction furnace 300.By adopting the system of preparing polysilicon of the above embodiment of the present invention that water cycle can be realized and heat energy mates, significantly save energy consumption thus.

As shown in Figure 3, according to the system of preparing polysilicon of the embodiment of the present invention, also further comprise: gas gas heat exchanger 410, gas gas heat exchanger 410 is connected with hydrogen heating unit 100, trichlorosilane heating unit 200, reduction furnace 300 and gas-liquid heat exchanger 400 respectively, through the hydrogen of heat treated and the temperature of trichlorosilane, it is 110 degrees Celsius, to before obtaining being incorporated into reduction furnace 300 through the hydrogen of heat treated and trichlorosilane, adopt in advance reduction tail gas to be preheated to 180 degrees Celsius.Thus the heat energy of reduction tail gas is made full use of and improves reduction reaction efficiency.

According to a particular embodiment of the invention, the above-mentioned system of preparing polysilicon further comprises: supplementary feed device 700 and heating unit 800, supplementary feed device 700 is connected with hot water mixing device 500, to add supplementary feed in reduction workshop section hot water.Heating unit 800 is connected with hot water mixing device 500, so that after adding reduction workshop section hot water heating to 150 after supplementary feed degree Celsius and as the thermal source of rectifying tower.In the time of can guaranteeing that thus the water yield when reduction workshop section hot water can not meet in purifying technique institute's water consumption, the water yield lacking to supply in reduction workshop section hot water in time.

As shown in Figure 4, according to a particular embodiment of the invention, above-mentioned supplementary feed device 700 further comprises: Constant pressure tank 710, constant pressure tank 720, constant pressure pump 730 and tensimeter 740, and wherein, Constant pressure tank 710 is connected with hot water mixing device 500; Constant pressure pump 730 is arranged between Constant pressure tank 710 and constant pressure tank 720; Tensimeter 740 is connected with Constant pressure tank 710 and cuts a side of the water outlet that is arranged on proximity thermal water mixing device 500.Can adopt thus tensimeter 740 to monitor constantly the pressure of the water between reduction workshop section's hot water and purification workshop section, and then judge that whether the water yield is not enough.Simultaneously tensimeter 740 with determine power pump 730 and constant pressure tank 720 is connected, and then according to supplementary feed in the automatic thermotropism water mixing device 500 of tensimeter 740 pressure changing.Can avoid thus, because service discharge deficiency causes the rectifying tower fluctuation of trichlorosilane purification devices 600 large, affecting quality product.

Therefore, according to a particular embodiment of the invention, the above-mentioned system of preparing polysilicon can further include: refrigerating unit 900, refrigerating unit 900 is connected with device for supplying 700 with hot water mixing device 500, so that the thermal source using the first part of reduction workshop section hot water as rectifying tower is for purify trichlorosilane, the workshop section that simultaneously obtains purifying returns to water; And the second section of reduction workshop section hot water is carried out after cooling reducing the third part of workshop section's hot water and purification workshop section and returning to one of at least mixing of water with being selected from, to obtain temperature, be the supplementary feed of 130 degrees Celsius.

According to a particular embodiment of the invention, when hot water amount described in the amount of the reduction workshop section hot water that hot water mixing device 500 provides has exceeded trichlorosilane purification devices 600, the system of preparing polysilicon of the above embodiment of the present invention can also be by adopting lower array apparatus to reach the coupling of the water yield.According to a particular embodiment of the invention, refrigerating unit 900 is connected with hot water mixing device 500, hydrogen heating unit 100, trichlorosilane heating unit 200 and reduction furnace 300, so that the thermal source using the first part of reduction workshop section hot water as rectifying tower is for purify trichlorosilane, the workshop section that simultaneously obtains purifying returns to water; The second section of reduction workshop section hot water is carried out after cooling reducing the third part of workshop section's hot water and purification workshop section and returning to one of at least mixing of water with being selected from, and is the water of 130 degrees Celsius to obtain temperature; And by resulting temperature, be that the water of 130 degrees Celsius is for respectively to hydrogen with trichlorosilane heats and reduction furnace is carried out to water-cooled.

Thus, obtaining the water of 130 degrees Celsius after the water of redundance can being lowered the temperature by refrigerating unit 900 again returns to water with purification workshop section to return to hydrogen heating unit 100, trichlorosilane heating unit 200 and reduction furnace 300 cooling for heating and the reduction furnace of raw material.And the present invention by the sub-fraction of reduction workshop section hot water unnecessary in hot water mixing device 500 is carried out cooling after and another part be mixed to get the water of 130 degrees Celsius, and then can save cooling energy consumption.

By adopting the system of preparing polysilicon of the above embodiment of the present invention, the hot water amount of reduction workshop section in hot water mixing device 500 and trichlorosilane purification devices 600 rectifying tower institute water requirements are when identical, only need in advance hydrogen heating unit 100, trichlorosilane heating unit 200 and the required water of reduction furnace 300 be heated to after 130 degrees Celsius, the heat that makes full use of reduction tail gas in follow-up working cycle can arrive whole process water circulation, without extra heat, cold and extra supplementary feed.Can significantly save the water yield and energy consumption thus.

By adopting the system of preparing polysilicon of the above embodiment of the present invention, when the hot water amount of reduction workshop section in hot water mixing device 500 is less than trichlorosilane purification devices 600 rectifying tower institute water requirement, can tensimeter 740 monitor force by device for supplying 700 change after automatically adding supplementary feed in the reduction workshop section hot water of thermotropism water mixing devices 500 and utilize heating unit 800 to be heated to approximately 150 degrees Celsius, and then avoid affecting not due to water shortage or temperature the quality product of trichlorosilane purification devices 600.

By adopting the system of preparing polysilicon of the above embodiment of the present invention, the hot water amount of reduction workshop section in hot water mixing device 500 is when with trichlorosilane purification devices 600 rectifying tower institute water requirement, unnecessary hot water can be divided into two portions, utilize refrigerating unit 900 to carry out a part wherein cooling, and then be again delivered in hydrogen heating unit 100, trichlorosilane heating unit 200 and reduction furnace 300 after making unnecessary hot water temperature be down to 130 degrees Celsius.

In accordance with a further aspect of the present invention, the present invention proposes a kind of system of purify trichlorosilane, wherein trichlorosilane contains dichloro-dihydro silicon and silicon tetrachloride, as shown in Figure 5, according to the system of the purify trichlorosilane of the embodiment of the present invention, comprises:

The first rectification cell 100, the first rectification cell 100 is for carrying out the first rectification process to trichlorosilane, to obtain gas and the first liquid heavy constituent after liquid after trichlorosilane, the first condensation, the first condensation, wherein, after the first condensation, liquid contains dichloro-dihydro silicon and trichlorosilane, and the first liquid heavy constituent contains silicon tetrachloride and trichlorosilane;

The second rectifier unit 200, the second rectifier unit 200 is connected with the first rectification cell 100, for the first liquid heavy constituent is carried out to the second rectification process, to obtain gas and the second liquid heavy constituent after liquid after the second condensation, the second condensation, wherein, after the second condensation, liquid contains silicon tetrachloride;

Condensing works 300, condensing works 300 is connected with the second rectifier unit 200 with the first rectification cell 100, for to gas after gas after the first condensation and the second condensation one of at least carry out condensation process, to obtain after the 3rd condensation gas after liquid and the 3rd condensation; And

The 3rd rectifier unit 400, the 3rd rectifier unit 400 is connected with condensing works 300 with the first rectification cell 100, for liquid after liquid after the first condensation and the 3rd condensation one of at least carried out to the 3rd rectification process, to obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation, wherein, after the 4th condensation, liquid contains dichloro-dihydro silicon, and the 3rd liquid heavy constituent contains trichlorosilane;

Wherein, the thermal source one of at least of the first rectification cell 100, the second rectifier unit 200, the 3rd rectifier unit 400 is reduction workshop section hot water, and reduction workshop section hot water is from the system of preparing polysilicon, as shown in Figure 2, prepares polysilicon system and comprises:

Hydrogen heating unit 100, trichlorosilane heating unit 200, reduction furnace 300, gas-liquid heat exchanger 400, hot water mixing device 500 and trichlorosilane purification devices 600.

Wherein, described hot water mixing device 500 and the first rectification cell 100, the second rectifier unit 200, the 3rd rectifier unit 400 one of is at least connected.

Below with reference to Fig. 5, the system of the purify trichlorosilane of the embodiment of the present invention is described in detail.According to embodiments of the invention, this system comprises:

The first rectification cell 100: according to embodiments of the invention, the first rectification cell 100 carries out the first rectification process for trichlorosilane, thus gas and the first liquid heavy constituent after liquid after trichlorosilane, the first condensation, the first condensation can be obtained respectively.According to embodiments of the invention, after the first condensation, liquid can contain dichloro-dihydro silicon and trichlorosilane, and the first liquid heavy constituent can contain silicon tetrachloride and trichlorosilane.According to embodiments of the invention, can adopt the rectifying tower of a plurality of series connection to carry out the first rectification process, according to a particular embodiment of the invention, can adopt the rectifying tower of five series connection to carry out the first rectification process.According to concrete example of the present invention, the rectifying tower of five series connection comprises the first to the 5th rectifying tower, and each includes: liquid outlet at the bottom of tower body, overhead gas outlet, tower, opening for feed, condensation separator, well heater, wherein, in tower body, limit rectifying space, be suitable for the material in rectifying space to carry out rectification process, thereby can obtain respectively liquid and overhead gas at the bottom of tower; Overhead gas outlet is arranged on the top of tower body, is suitable for exporting overhead gas; At the bottom of tower, liquid outlet is arranged on the bottom of tower body, is suitable for exporting liquid at the bottom of tower; Opening for feed is arranged on tower body, is suitable for introducing the material for the treatment of rectifying in rectifying space; Condensation separator is connected with overhead gas outlet, is suitable for overhead gas to carry out condensation separation processing, thereby can obtains condensing air and phlegma; Well heater is connected with tower body, is suitable for rectifying space to heat.

Concrete, by well heater, heat treated is carried out in the first rectifying tower rectifying space, then by opening for feed, in rectifying space, add trichlorosilane (coarse fodder that contains 85% left and right trichlorosilane), the light constituent that makes to contain a large amount of dichloro-dihydro silicon and the mixed gas of lower boiling impurity are discharged from top gas outlet, then mixed gas is carried out to condensation separation processing through condensation separator, thereby after the first rectifying tower condensation that can obtain respectively containing dichloro-dihydro silicon and trichlorosilane liquid and the first rectifying tower condensation after gas, and heavy constituent and high boiling impurity as the first rectifying tower at the bottom of liquid from furnace bottom liquid outlet, discharge.According to embodiments of the invention, the first rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.245MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.298MPaG, and service temperature is 77～79 ℃, and reflux ratio is 133.5.At the bottom of the first rectifying tower, liquid carries out rectification process as the rectifying material for the treatment of of Second distillation column, most of silicon tetrachloride, heavy constituent impurity and high-boiling-point impurity can be removed, thereby liquid at the bottom of gas and Second distillation column tower can be obtained respectively after liquid after Second distillation column condensation, Second distillation column condensation.According to embodiments of the invention, Second distillation column can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.243MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.297MPaG, and service temperature is 84～87 ℃, and reflux ratio is 14.5.After Second distillation column condensation, liquid carries out rectification process as the rectifying material for the treatment of of the 3rd rectifying tower, can further remove light constituent impurity residual in material, make light constituent foreign matter content in material reach the requirement of electronic-grade trichlorosilane, thereby can obtain respectively after liquid after the 3rd rectifying tower condensation, the 3rd rectifying tower condensation liquid at the bottom of gas and the 3rd rectifying tower.According to embodiments of the invention, the 3rd rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.25MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.304MPaG, and service temperature is 77～79 ℃, and reflux ratio is 128.5.At the bottom of the 3rd rectifying tower, liquid treats that as the 4th rectifying tower rectifying material carries out rectification process, the heavy constituent impurity of the middle remnants in material can be removed, thereby liquid at the bottom of gas and the 4th rectifying tower can be obtained respectively after liquid after the 4th rectifying tower condensation, the 4th rectifying tower condensation.According to embodiments of the invention, the 4th rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is that 32nd～55 blocks of column plates go out, and tower top working pressure is 0.250MPaG, service temperature is 71～73 ℃, tower reactor working pressure 0.303MPaG is, service temperature is 77～79 ℃, and reflux ratio is 18.After the 4th rectifying tower condensation, liquid carries out rectification process as the rectifying material for the treatment of of the 5th rectifying tower, remaining heavy constituent impurity can be further removed in material, thereby liquid at the bottom of gas and the 5th rectifying tower can be obtained after liquid after the 5th rectifying tower condensation, the 5th rectifying tower condensation.According to embodiments of the invention, the 5th rectifying tower can be high-efficiency guide sieve-plate tower, tower internal diameter is 1500mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.246MPaG, service temperature is 71～73 ℃, tower reactor working pressure is 0.298MPaG, and service temperature is 77～79 ℃, and reflux ratio is 20.

The second rectifier unit 200: according to embodiments of the invention, the second rectifier unit 200 is connected with the first rectification cell, for the liquid heavy constituent of above gained first is carried out to the second rectification process, thereby can obtain gas and the second liquid heavy constituent after liquid after the second condensation, the second condensation.According to embodiments of the invention, after the second condensation, in liquid, contain silicon tetrachloride.According to a particular embodiment of the invention, liquid at the bottom of the first to the 5th rectifying tower tower one of at least can be carried out to the second rectification process, for example, liquid at the bottom of Second distillation column tower can be carried out to the second rectification process as the first liquid heavy constituent.According to embodiments of the invention, the second liquid restructuring is divided into waste liquid, can directly be delivered to liquid waste disposal operation and process.Contriver finds, contains silicon tetrachloride and a large amount of heavy constituent impurity at the bottom of Second distillation column tower in liquid, can effectively remove most heavy constituent impurity, thereby can obtain finished product silicon tetrachloride by carrying out the second rectification process.Particularly, the second rectifier unit can be high-efficiency guide sieve-plate tower, tower internal diameter is 2200mm, stage number is 60, and opening for feed is 25th～45 blocks of column plates, and tower top working pressure is 0.213MPaG, service temperature is 89～92 ℃, tower reactor working pressure is 0.223MPaG, and service temperature is 128～131 ℃, and reflux ratio is 4.5.

Condensing works 300: according to embodiments of the invention, condensing works 300 is connected with the second rectifier unit 200 with the first rectification cell 100, for to gas after gas and the second condensation after above gained the first condensation one of at least carry out condensation process, thereby can obtain after the 3rd condensation gas after liquid and the 3rd condensation.According to embodiments of the invention, the condition of condensation process is also not particularly limited, and according to a particular embodiment of the invention, condensation process can be to carry out under-40～-38 degrees Celsius and the pressure condition that is 0.1～0.15MPaG in temperature.Contriver finds, the condensation process of carrying out under this condition can obviously improve after condensation the separation efficiency of liquid after gas and condensation.According to embodiments of the invention, after the condensation one of at least producing that can the using first to the 5th rectifying tower, gas gas after the first condensation carries out condensation process.Contriver finds, contains a large amount of dichloro-dihydro silicon and a small amount of trichlorosilane after the first condensation after gas and the second condensation in gas, is carried out carrying out subsequent disposal after condensation process again, can significantly improve the utilization ratio of material, can reduce exhaust emissions amount simultaneously.According to embodiments of the invention, after the 3rd condensation, in gas, contain noncondensable gas, can directly be sent to off gas treatment operation and process.According to a particular embodiment of the invention, condensing works can be double-tube sheet shell and tube heat exchanger, heat exchanger tube pass fluid is gas after each tower condensation, shell-side fluid is-38 ℃ of chilled brines, in upper cover, there is a pass partition, dividing plate one side has gas admission port after each tower condensation, and opposite side has noncondensable gas discharge outlet, and lower cover has a condensate discharge mouth.

The 3rd rectifier unit 400: according to embodiments of the invention, the 3rd rectifier unit is connected with condensing works 300 with the first rectification cell 100, for to liquid after liquid after the first condensation and the 3rd condensation one of at least carry out the 3rd rectification process, thereby can obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation.According to a particular embodiment of the invention, after the 4th condensation, in liquid, contain dichloro-dihydro silicon, the 3rd liquid heavy constituent contains trichlorosilane.According to embodiments of the invention, after the condensation can the using first to the 5th rectifying tower one of at least producing, liquid liquid after the first condensation carries out the 3rd rectification process.For example, after the condensation that, the first and the 3rd rectifying tower can be produced, after liquid and the 3rd condensation, liquid carries out the 3rd rectification process.Contriver finds, after the first and the 3rd rectifying tower condensation, in liquid, contain more than 99% trichlorosilane, the dichloro-dihydro silicon less than 1% and a large amount of light constituent impurity (as the compound of boron), by the 3rd rectification process, can remove most of dichloro-dihydro silicon and the lower-boiling impurity in light constituent material, and can reach more than 99.99% through trichlorosilane content in the 3rd rectification process gained the 3rd liquid heavy constituent.According to embodiments of the invention, the 3rd rectifier unit can be high-efficiency guide sieve-plate tower, tower internal diameter is 1200mm, stage number is 76, and opening for feed is 32nd～55 blocks of column plates, and tower top working pressure is 0.248MPaG, service temperature is 55～58 ℃, tower reactor working pressure is 0.298MPaG, and service temperature is 77～79 ℃, and reflux ratio is 47.

According to the system of the purify trichlorosilane of the embodiment of the present invention, can prepare the required trichlorosilane of electronic-grade polycrystalline silicon, and by gas centralized recovery after gas and the second condensation after the condensation that the first to the 5th rectifying tower is produced, and gas after condensation is concentrated and carried out condensation process, can obviously reduce the consumption of cold and the discharge of tail gas, liquid at the bottom of Second distillation column tower is proceeded to rectification process simultaneously, can obtain silicon tetrachloride product, in addition, after the condensation that the first to the 5th rectifying tower one of is at least produced, after liquid and the 3rd condensation, liquid is proceeded rectification process, can effectively trichlorosilane wherein be carried out separated with dichloro-dihydro silicon.

According to a particular embodiment of the invention, one of being at least connected with the hot water mixing device 500 in the system of preparing polysilicon of above-described embodiment of above-mentioned the first rectification cell, the second rectifier unit, the 3rd rectifier unit, utilize thus reduction workshop section hot water to heat the first rectification cell, the second rectifier unit, the 3rd rectifier unit, the cold water of simultaneously discharging and the hot water inlet 130 of hydrogen heating unit 100 and trichlorosilane heating unit 200 are connected with 230 and the cooling water inlet 340 of water-cooled assembly.

Embodiment

With reference to figure 6-7, high temperature water inlet (24) after each rectifying tower system heat exchange is with 0.6MPaG, 130 ℃ to enter respectively each chassis of reducing furnace cooling, chuck is cooling, tail gas is cooling, the cooling water inlet in chassis (6) through with chassis of reducing furnace heat exchange after be heated to 150 ℃, the cooling water inlet of chuck (4) through with the heat exchange of reduction furnace bell jar after be heated to 150 ℃, the cooling water inlet of tail gas (1) and reduction furnace feeding trichlorosilane liquid (9) well heater (E1), hydrogen gas (8) well heater (E2) carries out heat exchange, trichlorosilane, hydrogen is vaporized through 130 ℃ of hot water heatings, mix by a certain percentage, form 110 ℃ of mixed gass (10), mixed gas (10) enters reduction furnace mixed gas preheater (E3), enter and in reduction furnace, carry out polysilicon deposition with 580 ℃ of-610 ℃ of reduction furnace tail gas (12) heat exchange gas mixture (11) that is 180 ℃, after mixed gas well heater (E3) heat exchange, reduce tail gas (13), enter again reduction exhaust gas cooler (E4) and carry out heat exchange with the tail gas water coolant (2) of trichlorosilane, hydrogen heater outlet, by 100 ℃ of-110 ℃ of reduction furnace tail gas of heat exchange (14) to device for recovering tail gas,

(3) 140 ℃-145 ℃, tail gas water coolant backwater and chuck cooling backwater (5), chassis water coolant backwater (7) are mixed into reduction furnace high-temperature tempering house steward (25), with pump (P2), boost to 1.0MPaG and be sent to steam heater (E5), enter again each rectifying tower reboiler heat exchange, reduction furnace high-temperature tempering (22) and each rectifying tower reboiler heat exchange to 130 ℃, after water recirculator (E6), (23) are returned to each reduction furnace and are carried out cooling heat transferring, recycle.

High-temperature water system adopts closed type, for making high-temperature water system pressure and stability of flow, between reduction furnace high-temperature water pipeline (23) and constant pressure pump (P1), increased a Constant pressure tank, on the pipeline being connected with reduction furnace high-temperature water, (17) increase tensimeter simultaneously, tensimeter will directly show jacket water (J.W.) system pressure, when system pressure is when arranging minimum pressure 0.97MPaG, tensimeter is by the given water pump of transmission signal (P1), level pressure water pump (P1) is started working, and by (14), high-temperature tempering pipeline (15) is carried out to supercharging; When system pressure is greater than when top pressure 1.05MPAG is set, tensimeter is by the given water pump of transmission signal (P1), and level pressure water pump (P1) quits work.After level pressure water pump (P1) quits work, high-temperature water system pressure compensates by Constant pressure tank, when high-temperature water system pressure drop, the gas in Constant pressure tank is wanted naturally to expand, and interior water automatically fills into high-temperature tempering pipeline (15) through (14) under gaseous tension; Water in Constant pressure tank is reduced to a certain degree, by level pressure water pump, realizes supercharging, and the gas in tank is again compressed.Work and so forth, high-temperature water system carries out voltage stabilizing and moisturizing.

Reduction furnace high-temperature tempering is as the direct heat source of rectifying tower system reboiler, reduction furnace start-stop can be to rectifying tower system temperature in process of production, flow causes fluctuation and the system system hot water temperature that drives for the first time not to reach rectifying tower reboiler temperature, flow, before entering rectifying tower system reboiler, reduction furnace high-temperature tempering (20) increases a steam heater (E5), steam (28) is with 1.2MPaG, 190 ℃ are heated to 150 ℃ by reduction steam heater (E5) by reduction furnace high-temperature tempering (20), reduction steam heater (E5) bottom steam water of condensation (29) is got back to boiler, high-temperature tempering house steward (23) and reduction high-temperature water house steward enter, going out bypass (15) regulates, make to enter rectifying tower system high-temperature water (21) temperature and stability of flow at 150 ℃, 1700m ³/ h, has guaranteed that rectifying tower processing parameter is stable, rectifying tower system partly stops tower to operation reduction furnace high temperature water inlet (23) temperature in process of production, flow can cause fluctuation, at rectifying tower reboiler, enter (17), return main (22) increases a set of recirculated water plate-type heat exchanger (E6), recirculated water enters (26), recirculated water water outlet (27) is undertaken cooling by recirculated water plate-type heat exchanger (E6) by high-temperature cooling water (19), enter steam heater (E5) reduction furnace high temperature water inlet manifold (17) bypass (18) and arrive rectifying tower system water plate-type heat exchanger reboiler backwater (22) afterwards, rely on bypass (18) to regulate, guaranteed to enter reducing furnace system high temperature cooling water inlet (23) temperature, stability of flow is at 130 ℃, 2100m ³/ h.

5000 tons/year of polycrystalline silicon production lines, reduction direct consumption of electr ic energy 70kw.h/kgsi, product 625kg silicon per hour, chuck, chassis, tail gas water coolant are taken away approximately 80% heat, the heat of reduction furnace chuck, chassis, the recovery per hour of tail gas water coolant: 35000KW.Reduction furnace chuck, chassis, tail gas water coolant by 130 ℃ of water inlets, 150 ℃ of water outlets, 20 ℃ of calculating of the temperature difference, the total Water needing: 35000*860.6/20=1506m ³/ h;

Distillation system amounts to 13 towers, and 6, synthetic material rectifying tower, reverts back 6, rewinding rectifying tower, 1, silicon tetrachloride rectifying tower, and each tower reboiler institute thermal losses of synthetic material rectifying tower is 1870KW, the heat dissipation water 78m of institute ³/ h, reverting back each tower reboiler institute thermal losses of rewinding rectifying tower is 3920KW, the heat dissipation water 164m of institute ³/ h, silicon tetrachloride rectifying tower reboiler institute thermal losses is 3950KW, the heat dissipation water 165m of institute ³/ h; It is 38690KW that rectifying tower system amounts to institute's thermal losses, the heat dissipation water 1617m of institute ³/ h;

After reduction furnace chuck, chassis, the comprehensive utilization of tail gas cooled water heat energy, whole distillation system only need to supplement 5.2t/h steam and can meet, reduction furnace high-temperature water does not need circulating water, distillation system does not need steam heating, can amount to steam 50t/h for rectifying tower system minimizing heat per hour 35000KW, steam is by 140 yuan/ton of calculating, per hourly 7000 yuan can be saved, 5,040 ten thousand yuan can be saved the whole year.Reduction chuck, chassis, tail gas water coolant are pressed circulating water, 5 ℃ of temperature difference of recirculated water, and quantity of circulating water is exactly 35000X861.24 ÷ 5 ÷ 1000=6028m so ³/ h, a water circulating pump flow is 5000m ³/ h, a water circulating pump power is 1000kw.h, separate unit power of fan is 180kw.h, by 0.5 yuan/kw.h, calculates: per hourly can save 590 yuan, can save 424.8 ten thousand yuan the whole year; Circulating water system year is saved moisturizing 100000m ³, every Fang Shui is by 5 yuan of calculating, and year is saved 500,000 yuan.

Three add up to save the whole year: ten thousand yuan of 5040+424.8+50=5514.8

The technology transformation can make distillation system reduce by 91% steam consumption, makes device for recovering tail gas reduce refrigerator load 5%, and reduction power consumption reduces by 10%, and full factory recirculated water consumption reduces approximately 33.4%.

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, to the schematic statement of above-mentioned term needn't for be identical embodiment or example.And, the specific features of description, structure, material or feature can one or more embodiment in office or example in suitable mode combination.In addition,, not conflicting in the situation that, those skilled in the art can carry out combination and combination by the feature of the different embodiment that describe in this specification sheets or example and different 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, and those of ordinary skill in the art can change above-described embodiment within the scope of the invention, modification, replacement and modification.

Claims

1. a method of preparing polysilicon, is characterized in that, comprising:

2. method according to claim 1, is characterized in that, the hot water temperature who adopts in step (1) is 130 degrees Celsius, adopts the water of 130 degrees Celsius respectively described water-cooled to be carried out in the chassis of described reduction furnace and chuck in step (2).

3. method according to claim 1, it is characterized in that, described is 110 degrees Celsius through the hydrogen of heat treated and the temperature of trichlorosilane, and by before the resulting described hydrogen through heat treated and trichlorosilane are incorporated into described reduction furnace in step (1), adopt in advance described reduction tail gas to be preheated to 180 degrees Celsius.

4. method according to claim 1, is characterized in that, in step (4), comprising:

5. method according to claim 1, is characterized in that, described supplementary feed obtains through the following steps:

6. method according to claim 1, is characterized in that, in step (4), further comprises

7. a method for purify trichlorosilane, contains dichloro-dihydro silicon and tetrachloro hydrogen silicon in described trichlorosilane, it is characterized in that, described method comprises:

(4) liquid after liquid after described the first condensation and described the 3rd condensation one of at least carried out to the 3rd rectification process, to obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation, wherein, after described the 4th condensation, liquid contains dichloro-dihydro silicon, and described the 3rd liquid heavy constituent contains trichlorosilane

(1) utilize hot water respectively hydrogen and trichlorosilane to be heated, to obtain through the hot water of overcooled hot water and hydrogen and the trichlorosilane of process heat treated,

(4) described the first hot water and described the second hot water are mixed, to obtain described reduction workshop section hot water, wherein, the temperature of described the first hot water and described the second hot water is distinguished independently in the scope of 145～155 degrees Celsius.

8. a system of preparing polysilicon, is characterized in that, comprising:

Hydrogen heating unit and trichlorosilane heating unit, described hydrogen heating unit and trichlorosilane heating unit utilize hot water respectively hydrogen and trichlorosilane to be heated, to obtain hydrogen and trichlorosilane through overcooled hot water and process heat treated;

Reduction furnace, described reduction furnace is connected with trichlorosilane heating unit with described hydrogen heating unit respectively, for making described hydrogen and trichlorosilane through heat treated that reduction reaction occur in reduction furnace, to obtain polysilicon and reduction furnace tail gas, wherein, described reduction furnace has water-cooled assembly, and described reduction furnace is carried out to water-cooled, and obtains the first hot water;

9. the system of preparing polysilicon according to claim 8, is characterized in that, further comprises:

Gas gas heat exchanger, described gas gas heat exchanger is connected with described hydrogen heating unit, trichlorosilane heating unit, reduction furnace and gas-liquid heat exchanger respectively, described is 110 degrees Celsius through the hydrogen of heat treated and the temperature of trichlorosilane, to obtain, before described hydrogen through heat treated and trichlorosilane be incorporated into described reduction furnace, adopt in advance described reduction tail gas to be preheated to 180 degrees Celsius.

10. the system of preparing polysilicon according to claim 9, is characterized in that, further comprises:

Supplementary feed device, described supplementary feed device is connected with described hot water mixing device, to add supplementary feed in described reduction workshop section hot water;

11. systems of preparing polysilicon according to claim 10, is characterized in that, further comprise:

12. systems of preparing polysilicon according to claim 11, it is characterized in that, described refrigerating unit is connected with described hot water mixing device, hydrogen heating unit, trichlorosilane heating unit and reduction furnace, so that the thermal source using the first part of described reduction workshop section hot water as rectifying tower is for purify trichlorosilane, the workshop section that simultaneously obtains purifying returns to water; The second section of described reduction workshop section hot water is carried out after cooling returning to one of at least mixing of water with being selected from described third part of reducing workshop section's hot water and described purification workshop section, is the water of 130 degrees Celsius to obtain temperature; And by resulting temperature, be that the water of 130 degrees Celsius is for respectively to described hydrogen with trichlorosilane heats and described reduction furnace is carried out to water-cooled.

13. systems of preparing polysilicon according to claim 10, is characterized in that, described supplementary feed device further comprises:

Constant pressure tank;

Tensimeter, described tensimeter is connected with described Constant pressure tank and is arranged on a side of the water outlet of contiguous described hot water mixing device.

The system of 14. 1 kinds of purify trichlorosilanes, described trichlorosilane contains dichloro-dihydro silicon and silicon tetrachloride, it is characterized in that, and described system comprises:

The 3rd rectifier unit, described the 3rd rectifier unit is connected with described condensing works with described the first rectification cell, for liquid after liquid after described the first condensation and described the 3rd condensation one of at least carried out to the 3rd rectification process, to obtain gas and the 3rd liquid heavy constituent after liquid after the 4th condensation, the 4th condensation, wherein, after described the 4th condensation, liquid contains dichloro-dihydro silicon, and described the 3rd liquid heavy constituent contains trichlorosilane